@phdthesis{ALRawi2020,
  author    = {AL-Rawi, Shadha},
  title     = {Biochemical studies to determine the role of Early Starvation 1 (ESV1) protein and its homologue Like-Early Starvation 1 (LESV) during starch degradation},
  doi       = {10.25932/publishup-48395},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-483956},
  school      = {Universit{\"a}t Potsdam},
  pages     = {215},
  year      = {2020},
  abstract  = {Depending on the biochemical and biotechnical approach, the aim of this work was to understand the mechanism of protein-glucan interactions in regulation and control of starch degradation. Although starch degradation starts with the phosphorylation process, the mechanisms by which this process is controlling and adjusting starch degradation are not yet fully understood. Phosphorylation is a major process performed by the two dikinases enzymes α-glucan, water dikinase (GWD) and phosphoglucan water dikinase (PWD). GWD and PWD enzymes phosphorylate the starch granule surface; thereby stimulate starch degradation by hydrolytic enzymes. Despite these important roles for GWD and PWD, so far the biochemical processes by which these enzymes are able to regulate and adjust the rate of phosphate incorporation into starch during the degradation process haven't been understood. Recently, some proteins were found associated with the starch granule. Two of these proteins are named Early Starvation Protein 1 (ESV1) and its homologue Like-Early Starvation Protein 1 (LESV). It was supposed that both are involved in the control of starch degradation, but their function has not been clearly known until now. To understand how ESV1 and LESV-glucan interactions are regulated and affect the starch breakdown, it was analyzed the influence of ESV1 and LESV proteins on the phosphorylating enzyme GWD and PWD and hydrolysing enzymes ISA, BAM, and AMY. However, the analysis determined the location of LESV and ESV1 in the chloroplast stroma of Arabidopsis. Mass spectrometry data predicted ESV1and LESV proteins as a product of the At1g42430 and At3g55760 genes with a predicted mass of ~50 kDa and ~66 kDa, respectively. The ChloroP program predicted that ESV1 lacks the chloroplast transit peptide, but it predicted the first 56 amino acids N-terminal region as a chloroplast transit peptide for LESV. Usually, the transit peptide is processed during transport of the proteins into plastids. Given that this processing is critical, two forms of each ESV1 and LESV were generated and purified, a full-length form and a truncated form that lacks the transit peptide, namely, (ESV1and tESV1) and (LESV and tLESV), respectively. Both protein forms were included in the analysis assays, but only slight differences in glucan binding and protein action between ESV1 and tESV1 were observed, while no differences in the glucan binding and effect on the GWD and PWD action were observed between LESV and tLESV. The results revealed that the presence of the N-terminal is not massively altering the action of ESV1 or LESV. Therefore, it was only used the ESV1 and tLESV forms data to explain the function of both proteins. However, the analysis of the results revealed that LESV and ESV1 proteins bind strongly at the starch granule surface. Furthermore, not all of both proteins were released after their incubation with starches after washing the granules with 2\% [w/v] SDS indicates to their binding to the deeper layers of the granule surface. Supporting of this finding comes after the binding of both proteins to starches after removing the free glucans chains from the surface by the action of ISA and BAM. Although both proteins are capable of binding to the starch structure, only LESV showed binding to amylose, while in ESV1, binding was not observed. The alteration of glucan structures at the starch granule surface is essential for the incorporation of phosphate into starch granule while the phosphorylation of starch by GWD and PWD increased after removing the free glucan chains by ISA. Furthermore, PWD showed the possibility of starch phosphorylation without prephosphorylation by GWD. Biochemical studies on protein-glucan interactions between LESV or ESV1 with different types of starch showed a potentially important mechanism of regulating and adjusting the phosphorylation process while the binding of LESV and ESV1 leads to altering the glucan structures of starches, hence, render the effect of the action of dikinases enzymes (GWD and PWD) more able to control the rate of starch degradation. Despite the presence of ESV1 which revealed an antagonistic effect on the PWD action as the PWD action was decreased without prephosphorylation by GWD and increased after prephosphorylation by GWD (Chapter 4), PWD showed a significant reduction in its action with or without prephosphorylation by GWD in the presence of ESV1 whether separately or together with LESV (Chapter 5). However, the presence of LESV and ESV1 together revealed the same effect compared to the effect of each one alone on the phosphorylation process, therefore it is difficult to distinguish the specific function between them. However, non-interactions were detected between LESV and ESV1 or between each of them with GWD and PWD or between GWD and PWD indicating the independent work for these proteins. It was also observed that the alteration of the starch structure by LESV and ESV1 plays a role in adjusting starch degradation rates not only by affecting the dikinases but also by affecting some of the hydrolysing enzymes since it was found that the presence of LESV and ESV1leads to the reduction of the action of BAM, but does not abolish it.},
  language  = {en}
}
@phdthesis{Alirezaeizanjani2020,
  author    = {Alirezaeizanjani, Zahra},
  title     = {Movement strategies of a multi-mode bacterial swimmer},
  doi       = {10.25932/publishup-47580},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-475806},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xix, 111},
  year      = {2020},
  abstract  = {Bacteria are one of the most widespread kinds of microorganisms that play essential roles in many biological and ecological processes. Bacteria live either as independent individuals or in organized communities. At the level of single cells, interactions between bacteria, their neighbors, and the surrounding physical and chemical environment are the foundations of microbial processes. Modern microscopy imaging techniques provide attractive and promising means to study the impact of these interactions on the dynamics of bacteria. The aim of this dissertation is to deepen our understanding four fundamental bacterial processes - single-cell motility, chemotaxis, bacterial interactions with environmental constraints, and their communication with neighbors - through a live cell imaging technique. By exploring these processes, we expanded our knowledge on so far unexplained mechanisms of bacterial interactions. Firstly, we studied the motility of the soil bacterium Pseudomonas putida (P. putida), which swims through flagella propulsion, and has a complex, multi-mode swimming tactic. It was recently reported that P. putida exhibits several distinct swimming modes - the flagella can push and pull the cell body or wrap around it. Using a new combined phase-contrast and fluorescence imaging set-up, the swimming mode (push, pull, or wrapped) of each run phase was automatically recorded, which provided the full swimming statistics of the multi-mode swimmer. Furthermore, the investigation of cell interactions with a solid boundary illustrated an asymmetry for the different swimming modes; in contrast to the push and pull modes, the curvature of runs in wrapped mode was not affected by the solid boundary. This finding suggested that having a multi-mode swimming strategy may provide further versatility to react to environmental constraints. Then we determined how P. putida navigates toward chemoattractants, i.e. its chemotaxis strategies. We found that individual run modes show distinct chemotactic responses in nutrition gradients. In particular, P. putida cells exhibited an asymmetry in their chemotactic responsiveness; the wrapped mode (slow swimming mode) was affected by the chemoattractant, whereas the push mode (fast swimming mode) was not. These results can be seen as a starting point to understand more complex chemotaxis strategies of multi-mode swimmers going beyond the well-known paradigm of Escherichia coli, that exhibits only one swimming mode. Finally we considered the cell dynamics in a dense population. Besides physical interactions with their neighbors, cells communicate their activities and orchestrate their population behaviors via quorum-sensing. Molecules that are secreted to the surrounding by the bacterial cells, act as signals and regulate the cell population behaviour. We studied P. putida's motility in a dense population by exposing the cells to environments with different concentrations of chemical signals. We found that higher amounts of chemical signals in the surrounding influenced the single-cell behaviourr, suggesting that cell-cell communications may also affect the flagellar dynamics. In summary, this dissertation studies the dynamics of a bacterium with a multi-mode swimming tactic and how it is affected by the surrounding environment using microscopy imaging. The detailed description of the bacterial motility in fundamental bacterial processes can provide new insights into the ecology of microorganisms.},
  language  = {en}
}
@phdthesis{Amaechi2020,
  author    = {Amaechi, Mary Chimaobi},
  title     = {A'-movement dependencies and their reflexes in Igbo},
  doi       = {10.25932/publishup-47152},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471524},
  school      = {Universit{\"a}t Potsdam},
  pages     = {i, 195},
  year      = {2020},
  abstract  = {In this thesis, I examine different A-bar movement dependencies in Igbo, a Benue-Congo language spoken in southern Nigeria. Movement dependencies are found in constructions where an element is moved to the left edge of the clause to express information-structural categories such as in questions, relativization and focus. I show that these constructions in Igbo are very uniform from a syntactic point of view. The constructions are built on two basic fronting operations: relativization and focus movement, and are biclausal. I further investigate several morphophonological effects that are found in these A-bar constructions. I propose that these effects are reflexes of movement that are triggered when an element is moved overtly in relativization or focus. This proposal helps to explain the tone patterns that have previously been assumed to be a property of relative clauses. The thesis adds to the growing body of tonal reflexes of A-bar movement reported for a few African languages. The thesis also provides an insight into the complementizer domain (C-domain) of Igbo.},
  language  = {en}
}
@phdthesis{Anda2020,
  author    = {Anda, Carolin},
  title     = {Reisen mit/durch/auf Facebook},
  doi       = {10.25932/publishup-62489},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-624896},
  school      = {Universit{\"a}t Potsdam},
  pages     = {237},
  year      = {2020},
  abstract  = {Die vorliegende Arbeit untersucht Urlaubsfotografien bei Facebook und beschreibt, welche sozio-technischen Medienpraktiken sich innerhalb der Social-Media Plattform {\"u}ber die Fotografien vollziehen. Fotografische Praktiken sind durch aktive Handlungen und soziale Gebrauchsweisen bestimmt. Urlaubsfotografien tragen zum Beispiel zur Strukturierung von Reiserouten und Vorstellungen bei, indem genrespezifische Motive und Rahmungen mit Hilfe von Medien reproduziert und wiederholt werden. Praktiken des Zeigens, Teilens und Kommunizierens werden durch Social Plug-Ins (Like/Share Buttons) und Tagging-Funktionen auch in die Benutzeroberfl{\"a}chen von Facebook integriert. Dadurch werden Nutzer*innen Aktivit{\"a}ten und technische Prozesse miteinander verbunden. Am Beispiel der automatischen Generierung von Urlaubsfotografien auf Geotagseiten wird gezeigt, dass Social-Tagging zur Entstehung und Aushandlung geographischer R{\"a}ume und Ortsvorstellungen beitr{\"a}gt. Mithilfe technischer Strukturierungen von Fotografien auf Taggingseiten werden genrespezifische Motive, fotografische Trends und {\"A}sthetiken besonders sichtbar. Allerdings wird ihre Visualisierung auch durch algorithmische Priorisierung einzelner Inhalte mitbestimmt. Dadurch werden Urlaubsfotografien f{\"u}r ein fotografisches Profiling genutzt, da sie das algorithmische Erfassen und Auswerten von Nutzer*innen-Informationen erm{\"o}glichen. Die Arbeit zeigt, dass der Einsatz von Bilderkennungsverfahren und fotografischen Datenanalysen zu einer optimierten Informationsgewinnung und zu einer Standardisierung von Fotografien beitr{\"a}gt.},
  language  = {de}
}
@phdthesis{Aneley2020,
  author    = {Aneley, Gedif Mulugeta},
  title     = {Drought tolerance prediction of potato by automatic phenotyping of morphological and physiological traits},
  doi       = {10.25932/publishup-48683},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-486836},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xi, 176},
  year      = {2020},
  abstract  = {Potato is the 4th most important food crop in the world. Especially in tropical and sub-tropical potato production, drought is a yield limiting factor. Potato is sensitive to water stress. Potato yield loss under water stress could be reduced by using tolerant varieties and adjusted agronomic practices. Direct selection for yield under water-stressed conditions requires long selection cycles. Thus, identification of markers for marker-assisted selection may speed up breeding. The objective of this thesis is to identify morphological markers for drought tolerance by continuously monitoring plant growth and canopy temperature with an automatic phenotyping system. The phenotyping was performed in drought-stress experiments that were conducted in population A with 64 genotypes and population B with 21 genotypes in the screenhouse in 2015 and 2016 (population A) and in 2017 and 2018 (population B). Drought tolerance was quantified as deviation of the relative tuber starch yield from the experimental median (DRYM) and parent median (DRYMp). Relative tuber starch yield is starch yield under drought stress relative to the average starch yield of the respective cultivar under control conditions in the same experiment. The specific DRYM value was calculated based on the yield data of the same experiment or the global DRYM that was calculated from yield data derived from data combined over yeas of respective population or across multiple experiments including VALDIS and TROST experiments (2011-2016). Analysis of variance found a significant effect of genotype on DRYM indicating that the tolerance variation required for marker identification was given in both populations. Canopy growth was monitored continuously six times a day over five to ten weeks by a laser scanner system and yielded information on leaf area, plant height and leaf angle for population A and additionally on leaf inclination and light penetration depth for population B. Canopy temperature was measured 48 times a day over six to seven weeks by infrared thermometry in population B. From the continuous IRT surface temperature data set, the canopy temperature for each plant was selected by matching the time stamp of the IRT data with laser scanner data. Mean, maximum, range and growth rate values were calculated from continuous laser scanner measurements of respective canopy parameters. Among the canopy parameters, the maximum and mean values in long-term stress conditions showed better correlation with DRYM values calculated in the same experiment than growth rate and diurnal range values. Therefore, drought tolerance index prediction was done from maximum and mean values of canopy parameters. The tolerance index in specific experiment condition was linearly predicted by simple regression model from different single canopy parameters under long-term stress condition in population A (2016) and population B (2017 and 2018). Among the canopy parameters maximum light penetration depth (2017), mean leaf angle (2017, 2018, and 2016), mean leaf inclination or mean canopy temperature depression (2017 and 2018), maximum plant height (2017) were selected as tolerance predictors. However, no single parameters were sufficient to predict DRYM. Therefore, several independent parameters were integrated in a multiple regression model. In multiple regression model, specific experiment DRYM values in population A was predicted from mean leaf angle (2016). In population B, specific tolerance could be predicted from maximum light penetration depth and mean leaf inclination (2017) and mean leaf inclination (2018) or mean canopy temperature depression and mean leaf angle (2018). In data combined over season of population A, the multiple linear regression model selected maximum plant height and mean leaf angle as tolerance predictor. In Population B, mean leaf inclination was selected as tolerance predictor. However, in population A, the variation explained by the final model was too low. Furthermore, the average tolerances respective to parent median (2011-2018) across FGH plants or all plants (FGH and field) were predicted from maximum plant height (population A) and maximum plant height and mean leaf inclination (population B). Altogether, canopy parameters could be used as markers for drought tolerance. Therefore, water stress breeding in potato could be speed up through using leaf inclination, light penetration depth, plant height and canopy temperature depression as markers for drought tolerance, especially in long-term stress conditions.},
  language  = {en}
}
@phdthesis{Arentsen2020,
  author    = {Arentsen, Anke},
  title     = {Galactic archaeology with the oldest stars in the Milky Way},
  doi       = {10.25932/publishup-47602},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-476022},
  school      = {Universit{\"a}t Potsdam},
  year      = {2020},
  abstract  = {In einer dunklen Nacht kann man tausende Sterne sehen. All diese Sterne befinden sich innerhalb der Milchstraße, unsere Heimatgalaxie. Nicht alle Sterne sind gleich, sie k{\"o}nnen zum Beispiel unterschiedliche Gr{\"o}ßen, Massen, Temperaturen und Alter haben. Die schwereren Sterne leben (aus astronomischer Sicht) nicht lange, nur wenige Millionen Jahren, aber Sterne kleiner als die Sonne k{\"o}nnen mehr als zehn Milliarden Jahren alt werden. Kleine Sterne die ganz am Anfang des Universums entstanden sind leuchten immer noch. Diese uralten Sterne sind sehr hilfreich um mehr {\"u}ber das fr{\"u}he Universum, die erste Sterne und die Geschichte der Milchstraße zu erfahren. Aber wie erkennt man uralte Sterne? Anhand ihrer chemischen Fingerabdr{\"u}cke! Am Anfang des Universums gab es nur zwei chemische Elemente: Wasserstoff und Helium (und ein klein bisschen Lithium). Alle schwereren Elementen wie zum Beispiel Kohlenstoff, Kalzium und Eisen sind erst sp{\"a}ter innerhalb von Sternen und in Sternexplosionen entstanden. Je mehr Sternen geboren werden, sich entwickeln und explodieren, desto mehr chemische Elemente gibt es im Universum. Sterne die sp{\"a}ter entstehen werden mit einer gr{\"o}ßeren Menge an schweren Elementen, beziehungsweise einer gr{\"o}ßeren Metallizit{\"a}t, geboren. Im Bereich der Astronomie der sich „Galaktische Arch{\"a}ologie" nennt benutzt man Sterne mit unterschiedlichen Metallizit{\"a}ten um die Geschichte der Milchstraße zu erforschen. In dieser Doktorarbeit liegt der Fokus auf den metallarmen Sterne, da man erwartet dass diese Sterne am {\"a}ltesten sind und uns deswegen viel {\"u}ber die fr{\"u}he Geschichte erz{\"a}hlen k{\"o}nnen. Bis heute haben wir noch keinen metallfreien Stern entdeckt, aber die metall{\"a}rmsten Sterne geben uns wichtige Einblicke in das Leben und Sterben der ersten Sterne. Viele von diesen {\"a}ltesten, metall{\"a}rmsten Sternen haben unerwartet viel Kohlenstoff im Vergleich zu zum Beispiel Eisen. Diese kohlenstoffreichen, metallarmen Sterne (CEMP Sterne) erz{\"a}hlen uns etwas {\"u}ber die allerersten Sterne im Universum: sie haben relativ viel Kohlenstoff produziert. Wenn wir uns die genauen chemischen Fingerabdr{\"u}cke von CEMP Sterne angucken, erz{\"a}hlen sie uns noch viel mehr. Aber unsere Interpretation h{\"a}ngt von der Annahme ab, dass der chemische Fingerabdruck sich w{\"a}hrend des Lebens eines Sternes nicht ge{\"a}ndert hat. In dieser Dissertation werden neue Daten pr{\"a}sentiert die zeigen dass diese Annahme vielleicht zu einfach ist: viele extrem metallarme CEMP Sterne befinden sich in Doppelsternsystemen. Interaktion zwischen zwei Sternen in einem Doppelsternsystem k{\"o}nnte die Oberfl{\"a}che von CEMP Sternen verschmutzt haben. Zwar wurden die meisten CEMP Sterne h{\"o}chstwahrscheinlich nicht verschmutzt, aber wir sollten vorsichtig sein mit unserer Interpretation. Die CEMP Sterne und andere metallarme Sterne sind auch wichtig f{\"u}r unser Verst{\"a}ndnis der fr{\"u}hen Geschichte der Milchstraße. Die meisten Forscher, die metallarme Sterne studieren, suchen diese Sterne im Halo der Milchstraße: einer riesigen, diffuse Komponente die ungef{\"a}hr 1\% der Sterne in unserer Galaxie enth{\"a}lt. Modelle sagen aber vorher dass die {\"a}ltesten metallarmen Sterne sich im Zentrum der Milchstraße befinden (im „Bulge"). Das Zentrum ist leider, wegen großer Mengen Staub zwischen uns und dem Zentrum und einer {\"u}berw{\"a}ltigenden Mehrheit an metallreichen Sternen, schwierig zu beobachten. Diese Dissertation pr{\"a}sentiert Ergebnisse des „Pristine Inner Galaxy Survey" (PIGS), einer neuen Himmelsdurchmusterung, die die {\"a}ltesten Sterne im Bulge der Milchstraße sucht (und findet). PIGS benutzt Bilder mit einer Farbe, die f{\"u}r die Metallizit{\"a}t der Sterne empfindlich ist, und kann deswegen sehr effektiv die metallarmen Sterne aus Millionen anderer Sterne ausw{\"a}hlen. Von interessanten Kandidaten wurden Spektren aufgenommen und mit zwei unabh{\"a}ngigen Methoden analysiert. Mit dieser Strategie hat PIGS die bislang gr{\"o}ßte Anzahl an metallarmen Sternen in der inneren Galaxie entdeckt. Ein neues Ergebnis aus den PIGS Daten ist, dass die metall{\"a}rmeren Sterne langsamer um das Galaktische Zentrum drehen als die metallreichen Sterne, und dass sie mehr willk{\"u}rliche Bewegung zeigen. Eine zweite wichtige Leistung von PIGS ist die Entdeckung von dutzenden CEMP Sternen in der innere Galaxie, wo vorher nur zwei bekannt waren. Die neuen Ergebnisse aus dieser Dissertation helfen uns die ersten Sterne und die Geschichte der Milchstraße besser zu verstehen. Laufende und neue Himmelsdurchmusterungen in den n{\"a}chsten Jahren werden uns noch viel mehr Informationen geben: es ist eine aufregende Zeit f{\"u}r die Galaktische Arch{\"a}ologie.},
  language  = {en}
}
@phdthesis{Arya2020,
  author    = {Arya, Pooja},
  title     = {Light controlled active and passive motion of colloidal particles},
  doi       = {10.25932/publishup-48388},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-483880},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvii, 183},
  year      = {2020},
  abstract  = {In this dissertation we introduce a concept of light driven active and passive manipulation of colloids trapped at solid/liquid interface. The motion is induced due to generation of light driven diffusioosmotic flow (LDDO) upon irradiation with light of appropriate wavelength. The origin of the flow is due to osmotic pressure gradient resulting from a concentration gradient at the solid/liquid interface of the photosensitive surfactant present in colloidal dispersion. The photosensitive surfactant consists of a cationic head group and a hydrophobic tail in which azobenzene group is integrated in. The azobenzene is known to undergo reversible photo-isomerization from a stable trans to a meta stable cis state under irradiation with UV light. Exposure to light of larger wavelength results in back photo-isomerization from cis to trans state. The two isomers have different molecular properties, for instance, trans isomer has a rod like structure and low polarity (0 dipole moment), whereas cis one is bent and has a dipole moment of ~3 Debye. Being integrated in the hydrophobic tail of the surfactant molecule, the azobenzene state determines the hydrophobicity of the whole molecule: in the trans state the surfactant is more hydrophobic than in the cis-state. In this way many properties of the surfactant such as the CMC, solubility and the interaction potential with a solid surface can be altered by light. When the solution containing such a surfactant is irradiated with focused light, a concentration gradient of different isomers is formed near the boundary of the irradiated area near the solid surface resulting in osmotic pressure gradient. The generated diffusioosmotic (DO) flow carries the particles passively along. The local-LDDO flow can be generated around and by each particle when mesoporous silica colloids are dispersed in the surfactant solution. This is because porous particles act as a sink/source which absorbs azobenzene molecule in trans state and expels it when it is in the cis state. The DO flows generated at each particle interact resulting in aggregation or separation depending upon the initial state of surfactant molecules. The kinetic of aggregation and separation can be controlled and manipulated by altering the parameters such as the wavelength and intensity of the applied light, as well as surfactant and particle concentration. Using two wavelengths simultaneously allows for dynamic gathering and separation creating fascinating patterns such as 2D disk of well separated particles or establishing collective complex behaviour of particle ensemble as described in this thesis. The mechanism of l-LDDO is also used to generate self-propelled motion. This is possible when half of the porous particle is covered by metal layer, basically blocking the pores on one side. The LDDO flow generated on uncapped side pushes the particle forward resulting in a super diffusive motion. The system of porous particle and azobenzene containing surfactant molecule can be utilized for various application such as drug delivery, cargo transportation, self-assembling, micro motors/ machines or micro patterning.},
  language  = {en}
}
@phdthesis{Aseev2020,
  author    = {Aseev, Nikita},
  title     = {Modeling and understanding dynamics of charged particles in the Earth's inner magnetosphere},
  doi       = {10.25932/publishup-47921},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-479211},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxii, 154},
  year      = {2020},
  abstract  = {The Earth's inner magnetosphere is a very dynamic system, mostly driven by the external solar wind forcing exerted upon the magnetic field of our planet. Disturbances in the solar wind, such as coronal mass ejections and co-rotating interaction regions, cause geomagnetic storms, which lead to prominent changes in charged particle populations of the inner magnetosphere - the plasmasphere, ring current, and radiation belts. Satellites operating in the regions of elevated energetic and relativistic electron fluxes can be damaged by deep dielectric or surface charging during severe space weather events. Predicting the dynamics of the charged particles and mitigating their effects on the infrastructure is of particular importance, due to our increasing reliance on space technologies. The dynamics of particles in the plasmasphere, ring current, and radiation belts are strongly coupled by means of collisions and collisionless interactions with electromagnetic fields induced by the motion of charged particles. Multidimensional numerical models simplify the treatment of transport, acceleration, and loss processes of these particles, and allow us to predict how the near-Earth space environment responds to solar storms. The models inevitably rely on a number of simplifications and assumptions that affect model accuracy and complicate the interpretation of the results. In this dissertation, we quantify the processes that control electron dynamics in the inner magnetosphere, paying particular attention to the uncertainties of the employed numerical codes and tools. We use a set of convenient analytical solutions for advection and diffusion equations to test the accuracy and stability of the four-dimensional Versatile Electron Radiation Belt (VERB-4D) code. We show that numerical schemes implemented in the code converge to the analytical solutions and that the VERB-4D code demonstrates stable behavior independent of the assumed time step. The order of the numerical scheme for the convection equation is demonstrated to affect results of ring current and radiation belt simulations, and it is crucially important to use high-order numerical schemes to decrease numerical errors in the model. Using the thoroughly tested VERB-4D code, we model the dynamics of the ring current electrons during the 17 March 2013 storm. The discrepancies between the model and observations above 4.5 Earth's radii can be explained by uncertainties in the outer boundary conditions. Simulation results indicate that the electrons were transported from the geostationary orbit towards the Earth by the global-scale electric and magnetic fields. We investigate how simulation results depend on the input models and parameters. The model is shown to be particularly sensitive to the global electric field and electron lifetimes below 4.5 Earth's radii. The effects of radial diffusion and subauroral polarization streams are also quantified. We developed a data-assimilative code that blends together a convection model of energetic electron transport and loss and Van Allen Probes satellite data by means of the Kalman filter. We show that the Kalman filter can correct model uncertainties in the convection electric field, electron lifetimes, and boundary conditions. It is also demonstrated how the innovation vector - the difference between observations and model prediction - can be used to identify physical processes missing in the model of energetic electron dynamics. We computed radial profiles of phase space density of ultrarelativistic electrons, using Van Allen Probes measurements. We analyze the shape of the profiles during geomagnetically quiet and disturbed times and show that the formation of new local minimums in the radial profiles coincides with the ground observations of electromagnetic ion-cyclotron (EMIC) waves. This correlation indicates that EMIC waves are responsible for the loss of ultrarelativistic electrons from the heart of the outer radiation belt into the Earth's atmosphere.},
  language  = {en}
}
@phdthesis{Banerjee2020,
  author    = {Banerjee, Pallavi},
  title     = {Glycosylphosphatidylinositols (GPIs) and GPI-anchored proteins tethered to lipid bilayers},
  doi       = {10.25932/publishup-48956},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-489561},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xv, 141},
  year      = {2020},
  abstract  = {Glycosylphosphatidylinositols (GPIs) are highly complex glycolipids that serve as membrane anchors to a large variety of eukaryotic proteins. These are covalently attached to a group of peripheral proteins called GPI-anchored proteins (GPI-APs) through a post-translational modification in the endoplasmic reticulum. The GPI anchor is a unique structure composed of a glycan, with phospholipid tail at one end and a phosphoethanolamine linker at the other where the protein attaches. The glycan part of the GPI comprises a conserved pseudopentasaccharide core that could branch out to carry additional glycosyl or phosphoethanolamine units. GPI-APs are involved in a diverse range of cellular processes, few of which are signal transduction, protein trafficking, pathogenesis by protozoan parasites like the malaria- causing parasite Plasmodium falciparum. GPIs can also exist freely on the membrane surface without an attached protein such as those found in parasites like Toxoplasma gondii, the causative agent of Toxoplasmosis. These molecules are both structurally and functionally diverse, however, their structure-function relationship is still poorly understood. This is mainly because no clear picture exists regarding how the protein and the glycan arrange with respect to the lipid layer. Direct experimental evidence is rather scarce, due to which inconclusive pictures have emerged, especially regarding the orientation of GPIs and GPI-APs on membrane surfaces and the role of GPIs in membrane organization. It appears that computational modelling through molecular dynamics simulations would be a useful method to make progress. In this thesis, we attempt to explore characteristics of GPI anchors and GPI-APs embedded in lipid bilayers by constructing molecular models at two different resolutions - all-atom and coarse-grained. First, we show how to construct a modular molecular model of GPIs and GPI-anchored proteins that can be readily extended to a broad variety of systems, addressing the micro-heterogeneity of GPIs. We do so by creating a hybrid link to which GPIs of diverse branching and lipid tails of varying saturation with their optimized force fields, GLYCAM06 and Lipid14 respectively, can be attached. Using microsecond simulations, we demonstrate that GPI prefers to "flop-down" on the membrane, thereby, strongly interacting with the lipid heads, over standing upright like a "lollipop". Secondly, we extend the model of the GPI core to carry out a systematic study of the structural aspects of GPIs carrying different side chains (parasitic and human GPI variants) inserted in lipid bilayers. Our results demonstrate the importance of the side branch residues as these are the most accessible, and thereby, recognizable epitopes. This finding qualitatively agrees with experimental observations that highlight the role of the side branches in immunogenicity of GPIs and the specificity thereof. The overall flop-down orientation of the GPIs with respect to the bilayer surface presents the side chain residues to face the solvent. Upon attaching the green fluorescent protein (GFP) to the GPI, it is seen to lie in close proximity to the bilayer, interacting both with the lipid heads and glycan part of the GPI. However the orientation of GFP is sensitive to the type of GPI it is attached to. Finally, we construct a coarse-grained model of the GPI and GPI-anchored GFP using a modified version of the MARTINI force-field, using which the timescale is enhanced by at least an order of magnitude compared to the atomistic system. This study provides a theoretical perspective on the conformational behavior of the GPI core and some of its branched variations in presence of lipid bilayers, as well as draws comparisons with experimental observations. Our modular atomistic model of GPI can be further employed to study GPIs of variable branching, and thereby, aid in designing future experiments especially in the area of vaccines and drug therapies. Our coarse-grained model can be used to study dynamic aspects of GPIs and GPI-APs w.r.t plasma membrane organization. Furthermore, the backmapping technique of converting coarse-grained trajectory back to the atomistic model would enable in-depth structural analysis with ample conformational sampling.},
  language  = {en}
}
@phdthesis{Barbosa2020,
  author    = {Barbosa, Lu{\´i}s Romero},
  title     = {Groundwater recharge in tropical wet regions via GIS-based and cosmic-ray neutron sensing},
  doi       = {10.25932/publishup-46064},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-460641},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XXVI, 175},
  year      = {2020},
  abstract  = {Studies on the unsustainable use of groundwater resources are still considered incipient since it is frequently a poorly understood and managed, devalued and inadequately protected natural resource. Groundwater Recharge (GWR) is one of the most challenging elements to estimate since it can rarely be measured directly and cannot easily be derived from existing data. To overcome these limitations, many hydro(geo)logists have combined different approaches to estimate large-scale GWR, namely: remote sensing products, such as IMERG product; Water Budget Equation, also in combination with hydrological models, and; Geographic Information System (GIS), using estimation formulas. For intermediary-scale GWR estimation, there exist: Non-invasive Cosmic-Ray Neutron Sensing (CRNS); wireless networks from local soil probes; and soil hydrological models, such as HYDRUS. Accordingly, this PhD thesis aims, on the one hand, to demonstrate a GIS-based model coupling for estimating the GWR distribution on a large scale in tropical wet basins. On the other hand, it aims to use the time series from CRNS and invasive soil moisture probes to inversely calibrate the soil hydraulic properties, and based on this, estimating the intermediary-scale GWR using a soil hydrological model. For such purpose, two tropical wet basins located in a complex sedimentary aquifer in the coastal Northeast region of Brazil were selected. These are the Jo{\~a}o Pessoa Case Study Area and the Guara{\´i}ra Experimental Basin. Several satellite products in the first area were used as input to the GIS-based water budget equation model for estimating the water balance components and GWR in 2016 and 2017. In addition, the point-scale measurement and CRNS data were used in the second area to determine the soil hydraulic properties, and to estimate the GWR in the 2017-2018 and 2018-2019 hydrological years. The resulting values of GWR on large- and intermediary-scale were then compared and validated by the estimates obtained by groundwater table fluctuations. The GWR rates for IMERG- and rain-gauge-based scenarios showed similar coefficients between 68\% and 89\%, similar mean errors between 30\% and 34\%, and slightly-different bias between -13\% and 11\%. The results of GWR rates for soil probes and CRNS soil moisture scenarios ranged from -5.87 to -61.81 cm yr-1, which corresponds to 5\% and 38\% of the precipitation. The calculations of the mean GWR rates on large-scale, based on remote sensing data, and on intermediary-scale, based on CRNS data, held similar results for the Podzol soil type, namely 17.87\% and 17\% of the precipitation. It is then concluded that the proposed methodologies allowed for estimating realistically the GWR over the study areas, which can be a ground-breaking step towards improving the water management and decision-making in the Northeast of Brazil.},
  language  = {en}
}
@phdthesis{Barrionuevo2020,
  author    = {Barrionuevo, Mat{\´i}as},
  title     = {The role of the upper plate in the Andean tectonic evolution (33-36°S): insights from structural geology and numerical modeling},
  doi       = {10.25932/publishup-51590},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-515909},
  school      = {Universit{\"a}t Potsdam},
  pages     = {148, S2},
  year      = {2020},
  abstract  = {Los Andes Centrales del Sur (33-36°S) son un gran laboratorio para el estudio de los procesos de deformaci{\´o}n orog{\´e}nica, donde las condiciones de borde, como la geometr{\´i}a de la placa subductada, imponen un importante control sobre la deformaci{\´o}n andina. Por otro lado, la Placa Sudamericana presenta una serie de heterogeneidades que tambi{\´e}n imparten un control sobre el modo de deformaci{\´o}n. El objetivo de esta tesis es probar el control de este {\´u}ltimo factor sobre la construcci{\´o}n del sistema orog{\´e}nico andino. A partir de la integraci{\´o}n de la informaci{\´o}n superficial y de subsuelo en el {\´a}rea sur (34°-36°S), se estudi{\´o} la evoluci{\´o}n de la deformaci{\´o}n andina sobre el segmento de subducci{\´o}n normal. Se desarroll{\´o} un modelo estructural que eval{\´u}a el estado de esfuerzos desde el Mioceno hasta la actualidad, el rol de estructuras previas y su influencia en la migraci{\´o}n de fluidos. Con estos datos y publicaciones previas de la zona norte del {\´a}rea de estudio (33°-34ºS), se realiz{\´o} un modelado num{\´e}rico geodin{\´a}mico para probar la hip{\´o}tesis del papel de las heterogeneidades de la placa superior en la evoluci{\´o}n andina. Se utilizaron dos c{\´o}digos (LAPEX-2D y ASPECT) basados en elementos finitos/diferencias finitas, que simulan el comportamiento de materiales con reolog{\´i}as elastoviscopl{\´a}sticas bajo deformaci{\´o}n. Los resultados del modelado sugieren que la deformaci{\´o}n contraccional de la placa superior est{\´a} significativamente controlada por la resistencia de la lit{\´o}sfera, que est{\´a} definida por la composici{\´o}n de la corteza superior e inferior y por la proporci{\´o}n del manto litosf{\´e}rico, que a su vez est{\´a} definida por eventos tect{\´o}nicos previos. Estos eventos previos tambi{\´e}n definieron la composici{\´o}n de la corteza y su geometr{\´i}a, que es otro factor que controla la localizaci{\´o}n de la deformaci{\´o}n. Con una composici{\´o}n de corteza inferior m{\´a}s f{\´e}lsica, la deformaci{\´o}n sigue un modo de cizalla pura mientras que las composiciones m{\´a}s m{\´a}ficas provocan un modo de deformaci{\´o}n tipo cizalla simple. Por otro lado, observamos que el espesor inicial de la lit{\´o}sfera controla la localizaci{\´o}n de la deformaci{\´o}n, donde zonas con lit{\´o}sfera m{\´a}s fina es propensa a concentrar la deformaci{\´o}n. Un l{\´i}mite lit{\´o}sfera-asten{\´o}sfera asim{\´e}trico, como resultado del flujo de la cu{\~n}a mant{\´e}lica tiende a generar despegues vergentes al E.},
  language  = {en}
}
@phdthesis{Biedermann2020,
  author    = {Biedermann, Nicole},
  title     = {Carbonate-silicate reactions at conditions of the Earth's mantle and the role of carbonates as possible trace-element carriers},
  doi       = {10.25932/publishup-48277},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-482772},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvii, 127},
  year      = {2020},
  abstract  = {Carbonates play a key role in the chemistry and dynamics of our planet. They are directly connected to the CO2 budget of our atmosphere and have a great impact on the deep carbon cycle. Moreover, recent studies have shown that carbonates are stable along the geothermal gradient down to Earth's lower mantle conditions, changing their crystal structure and related properties. Subducted carbonates may also react with silicates to form new phases. These reactions will redistribute elements, such as calcium (Ca), magnesium (Mg), iron (Fe) and carbon in the form of carbon dioxide (CO2), but also trace elements, that are carried by the carbonates. The trace elements of most interest are strontium (Sr) and rare earth elements (REE) which have been found to be important constituents in the composition of the primitive lower mantle and in mineral inclusions found in super-deep diamonds. However, the stability of carbonates in presence of mantle silicates at relevant temperatures is far from being well understood. Related to this, very little is known about distribution processes of trace elements between carbonates and mantle silicates. To shed light on these processes, we studied reactions between Sr- and REE-containing CaCO3 and Mg/Fe-bearing silicates of the system (Mg,Fe)2SiO4 - (Mg,Fe)SiO3 at high pressure and high temperature using synchrotron radiation based μ-X-ray diffraction (μ-XRD) and μ-X-ray fluorescence (μ-XRF) with μm-resolution in a laser-heated diamond anvil cell. X-ray diffraction is used to derive the structural changes of the phase reactions whereas X-ray fluorescence gives information on the chemical changes in the sample. In-situ experiments at high pressure and high temperature were performed at beamline P02.2 at PETRA III (Hamburg, Germany) and at beamline ID27 at ESRF (Grenoble, France). In addition to μ-XRD and μ-XRF, ex-situ measurements were made on the recovered sample material using transmission electron microscopy (TEM) and provided further insights into the reaction kinetics of carbonate-silicate reactions. Our investigations show that CaCO3 is unstable in presence of mantle silicates above 1700 K and a reaction takes place in which magnesite plus CaSiO3-perovskite are formed. In addition, we observed that a high content of iron in the carbonate-silicate system favours dolomite formation during the reaction. The subduction of natural carbonates with significant amounts of Sr leads to a comprehensive investigation of the stability not only of CaCO3 phases in contact with mantle silicates but also of SrCO3 (and of Sr-bearing CaCO3). We found that SrCO3 reacts with (Mg,Fe)SiO3-perovskite to form magnesite and gained evidence for the formation of SrSiO3-perovskite. To complement our study on the stability of SrCO3 at conditions of the Earth's lower mantle, we performed powder X-ray diffraction and single crystal X-ray diffraction experiments at ambient temperature and up to 49 GPa. We observed a transformation from SrCO3-I into a new high-pressure phase SrCO3-II at around 26 GPa with Pmmn crystal structure and a bulk modulus of 103(10) GPa. This information is essential to fully understand the phase behaviour and stability of carbonates in the Earth's lower mantle and to elucidate the possibility of introducing Sr into mantle silicates by carbonate-silicate reactions. Simultaneous recording of μ-XRD and μ-XRF in the μm-range over the heated areas provides spatial information not only about phase reactions but also on the elemental redistribution during the reactions. A comparison of the spatial intensity distribution of the XRF signal before and after heating indicates a change in the elemental distribution of Sr and an increase in Sr-concentration was found around the newly formed SrSiO3-perovskite. With the help of additional TEM analyses on the quenched sample material the elemental redistribution was studied at a sub-micrometer scale. Contrary to expectations from combined μ-XRD and μ-XRF measurements, we found that La and Eu were not incorporated into the silicate phases, instead they tend to form either isolated oxide phases (e.g. Eu2O3, La2O3) or hydroxyl-bastn{\"a}site (La(CO3)(OH)). In addition, we observed the transformation from (Mg,Fe)SiO3-perovskite to low-pressure clinoenstatite during pressure release. The monoclinic structure (P21/c) of this phase allows the incorporation of Ca as shown by additional EDX analyses and, to a minor extent, Sr too. Based on our experiments, we can conclude that a detection of the trace elements in-situ at high pressure and high temperature remains challenging. However, our first findings imply that silicates may incorporate the trace elements provided by the carbonates and indicate that carbonates may have a major effect on the trace element contents of mantle phases.},
  language  = {en}
}
@phdthesis{Bombart2020,
  author    = {Bombart, Diane},
  title     = {The geometry of a complex institution},
  doi       = {10.25932/publishup-48872},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-488724},
  school      = {Universit{\"a}t Potsdam},
  pages     = {181},
  year      = {2020},
  abstract  = {Organizations incorporate the institutional demands from their environment in order to be deemed legitimate and survive. Yet, complexifying societies promulgate multiple and sometimes inconsistent institutional prescriptions. When these prescriptions collide, organizations are said to face "institutional complexity". How does an organization then incorporate incompatible demands? What are the consequences of institutional complexity for an organization? The literature provides contradictory conceptual and empirical insights on the matter. A central assumption, however, remains that internal incompatibilities generate tensions that, under certain conditions, can escalate into intractable conflicts, resulting in dysfunctionality and loss of legitimacy. The present research is an inquiry into what happens inside an organization when it incorporates complex institutional demands. To answer this question, I focus on how individuals inside an organization interpret a complex institutional prescription. I examine how members of the French Development Agency interpret 'results-based management', a central but complex concept of organizing in the field of development aid. I use an inductive mixed methods design to systematically explore how different interpretations of results-based management relate to one another and to the organizational context in which they are embedded. The results reveal that results-based management is a contested concept in the French Development Agency. I find multiple interpretations of the concept, which are attached to partly incompatible rationales about "who we are" and "what we do as an organization". These rationales nevertheless coexist as balanced forces, without escalating into open conflict. The analysis points to four reasons for this peaceful coexistence of diverging rationales inside one and the same organization: 1) individuals' capacity to manipulate different interpretations of a complex institutional demand, 2) the nature of interpretations, which makes them more or less prone to conflict, 3) the balanced distribution of rationales across the organizational sub-contexts and 4) the shared rules of interpretation provided by the larger socio-cultural context. This research shows that an organization that incorporates institutional complexity comes to represent different, partly incompatible things to its members without being at war with itself. In doing so, it contributes to our knowledge of institutional complexity and organizational hybridity. It also advances our understanding of internal organizational legitimacy and of the translation of managerial concepts in organizations.},
  language  = {en}
}
@phdthesis{Borghini2020,
  author    = {Borghini, Alessia},
  title     = {Melt inclusions in mafic rocks as witnesses of metasomatism in the Bohemian Massif},
  doi       = {10.25932/publishup-47363},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473639},
  school      = {Universit{\"a}t Potsdam},
  pages     = {205},
  year      = {2020},
  abstract  = {Orogenic peridotites represent portions of upper subcontinental mantle now incorporated in mountain belts. They often contain layers, lenses and irregular bodies of pyroxenite and eclogite. The origin of this heterogeneity and the nature of these layers is still debated but it is likely to involve processes such as transient melts coming from the crust or the mantle and segregating in magma conduits, crust-mantle interaction, upwelling of the asthenosphere and metasomatism. All these processes occur in the lithospheric mantle and are often related with the subduction of crustal rocks to mantle depths. In fact, during subduction, fluids and melts are released from the slab and can interact with the overlying mantle, making the study of deep melts in this environment crucial to understand mantle heterogeneity and crust-mantle interaction. The aim of this thesis is precisely to better constrain how such processes take place studying directly the melt trapped as primary inclusions in pyroxenites and eclogites. The Bohemian Massif, crystalline core of the Variscan belt, is targeted for these purposes because it contains orogenic peridotites with layers of pyroxenite and eclogite and other mafic rocks enclosed in felsic high pressure and ultra-high pressure crustal rocks. Within this Massif mafic rocks from two areas have been selected: the garnet clinopyroxenite in orogenic peridotite of the Granulitgebirge and the ultra-high pressure eclogite in the diamond-bearing gneisses of the Erzgebirge. In both areas primary melt inclusions were recognized in the garnet, ranging in size between 2-25 µm and with different degrees of crystallization, from glassy to polycrystalline. They have been investigated with Micro Raman spectroscopy and EDS mapping and the mineral assemblage is kumdykolite, phlogopite, quartz, kokchetavite, phase with a main Raman peak at 430 cm-1, phase with a main Raman peak at 412 cm-1, white mica and calcite with some variability in relative abundance depending on the case study. In the Granulitgebirge osumilite and pyroxene are also present, whereas calcite is one of the main phases in the Erzgebirge. The presence of glass and the mineral assemblage in the nanogranitoids suggest that they were former droplets of melt trapped in the garnet while it was growing. Glassy inclusions and re-homogenized nanogranitoids show a silicate melt that is granitic, hydrous, high in alkalis and weakly peraluminous. The melt is also enriched in both case studies in Cs, Pb, Rb, U, Th, Li and B suggesting the involvement of crustal component, i.e. white mica (main carrier of Cs, Pb, Rb, Li and B), and a fluid (Cs, Th and U) in the melt producing reaction. The whole rock in both cases mainly consists of garnet and clinopyroxene with, in Erzgebirge samples, the additional presence of quartz both in the matrix and as a polycrystalline inclusion in the garnet. The latter is interpreted as a quartz pseudomorph after coesite and occurs in the same microstructural position as the melt inclusions. Both rock types show a crustal and subduction zone signature with garnet and clinopyroxene in equilibrium. Melt was likely present during the metamorphic peak of the rock, as it occurs in garnet. Our data suggest that the processes most likely responsible for the formation of the investigated rocks in both areas is a metasomatic reaction between a melt produced in the crust and mafic layers formerly located in the mantle wedge for the Granulitgebirge and in the subducted continental crust itself in the Erzgebirge. Thus metasomatism in the first case took place in the mantle overlying the slab, whereas in the second case metasomatism took place in the continental crust that already contained, before subduction, mafic layers. Moreover, the presence of former coesite in the same microstructural position of the melt inclusions in the Erzgebirge garnets suggest that metasomatism took place at ultra-high pressure conditions. Summarizing, in this thesis we provide new insights into the geodynamic evolution of the Bohemian Massif based on the study of melt inclusions in garnet in two different mafic rock types, combining the direct microstructural and geochemical investigation of the inclusions with the whole-rock and mineral geochemistry. We report for the first time data, directly extracted from natural rocks, on the metasomatic melt responsible for the metasomatism of several areas of the Bohemian Massif. Besides the two locations here investigated, belonging to the Saxothuringian Zone, a signature similar to the investigated melt is clearly visible in pyroxenite and peridotite of the T-7 borehole (again Saxothuringian Zone) and the durbachite suite located in the Moldanubian Zone.},
  language  = {en}
}
@phdthesis{Brose2020,
  author    = {Brose, Robert},
  title     = {From dawn till dusk},
  doi       = {10.25932/publishup-47086},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-470865},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiii, 146},
  year      = {2020},
  abstract  = {Supernova remnants are believed to be the source of cosmic rays with energies up to 10^15 eV that are produced within our Galaxy. The acceleration mechanism associated with the collision-less shocks in supernova remnants - diffusive shock acceleration - predicts a spectral index of the accelerated non-thermal particles of s = 2. However, measurements of non-thermal emission in radio, X-rays and gamma-rays reveal significant deviations of the particles spectral index from the canonical value of s = 2. The youngest Galactic supernova remnant G1.9+0.3 is an interesting target for next-generation gamma-ray observatories. So far, the remnant is only detected in the radio and the X-ray bands, but its young age of ≈100 yrs and inferred shock speed of ≈ 14, 000 km/s could make it an efficient particle accelerator. I performed spherical symmetric 1D simulations with the RATPaC code, in which I simultaneously solved the transport equation for cosmic rays, the transport equation for magnetic turbulence, and the hydro-dynamical equations for the gas flow. Separately computed distributions of the particles accelerated at the forward and the reverse shock were then used to calculate the spectra of synchrotron, inverse Compton, and Pion-decay radiation from the source. The emission from G1.9+0.3 can be self-consistently explained within the test-particle limit. I find that the X-ray flux is dominated by emission from the forward shock while most of the radio emission originates near the reverse shock, which makes G1.9+0.3 the first remnant with non-thermal radiation detected from the reverse shock. The flux of very-high-energy gamma-ray emission from G1.9+0.3 is expected to be close to the sensitivity threshold of the Cherenkov Telescope Array. The limited time available to grow large-scale turbulence limits the maximum energy of particles to values below 100 TeV, hence G1.9+0.3 is not a PeVatron. Although there are many models for the acceleration of cosmic rays in Supernova remnants, the escape of cosmic rays from these sources is yet understudied. I use our time-dependent acceleration code RATPaC to study the acceleration of cosmic rays and their escape in post-adiabatic Supernova remnants and calculate the subsequent gamma-ray emission from inverse-Compton scattering and Pion decay. My simulations span 100,000 years, thus covering the free-expansion, the Sedov-Taylor, and the beginning of the post-adiabatic phase of the remnant's evolution. At later stages of the evolution cosmic rays over a wide range of energy can reside outside of the remnant, creating spectra that are softer than predicted by standard diffusive shock acceleration and feature breaks in the 10 - 100 GeV-range. The total spectrum of cosmic rays released into the interstellar medium has a spectral index of s ≈ 2.4 above roughly 10 GeV which is close to that required by Galactic propagation models. I further find the gamma-ray luminosity to peak around an age of 4,000 years for inverse-Compton-dominated high-energy emission. Remnants expanding in low-density media emit generally more inverse-Compton radiation matching the fact that the brightest known supernova remnants - RCW86, Vela Jr, HESSJ1721-347 and RXJ1713.7-3946 - are all expanding in low density environments. The importance of feedback from the cosmic-rays on the hydrodynamical evolution of the remnants is debated as a possibility to obtain soft cosmic-ray spectra at low energies. I performed spherically symmetric 1-D simulations with a modified version of the RATPaC code, in which I simultaneously solve the transport equation for cosmic rays and the hydrodynamical equations, including the back-reaction of the cosmic-ray pressure on the flow profiles. Besides the known modification of the flow profiles and the consequently curved cosmic-ray spectra, steady-state models for non-linear diffusive shock acceleration overpredict the total compression ratio that can be reached with cosmic-ray feedback, as there is limited time for building these modifications. Further, I find modifications to the downstream flow structure that change the evolutionary behavior of the remnant and trigger a cosmic-ray-induced instability close to the contact discontinuity, if and when the cosmic-ray pressure becomes dominant there.},
  language  = {en}
}
@phdthesis{Buechele2020,
  author    = {B{\"u}chele, Dominique},
  title     = {Entwicklung einer robusten Online-Methode zur Bestimmung von N{\"a}hrelementen in Ackerb{\"o}den mit einem Energie-dispersiven RFA-Sensor},
  doi       = {10.25932/publishup-48373},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-483735},
  school      = {Universit{\"a}t Potsdam},
  pages     = {IX, 106, XLV},
  year      = {2020},
  abstract  = {Im Rahmen der vom Bundesministerium f{\"u}r Bildung und -forschung gef{\"o}rderten Forschungsinitiative „BonaRes - Boden als nachhaltige Ressource der Bio{\"o}konomie" soll sich das Teilprojekt „I4S - integrated system for site-specific soil fertility management" der Entwicklung eines integrierten Systems zum ortsspezifischen Management der Bodenfruchtbarkeit widmen. Hierf{\"u}r ist eine Messplattform zur Bestimmung relevanter Bodeneigenschaften und der quantitativen Analyse ausgew{\"a}hlter Makro- und Mikron{\"a}hrstoffe geplant. In der ersten Phase dieses Projekts liegt das Hauptaugenmerk auf der Kalibrierung und Validierung der verschiedenen Sensoren auf die Matrix Boden, der Probennahme auf dem Acker und der Planung sowie dem Aufbau der Messplattform. Auf dieser Plattform sollen in der zweiten Phase des Projektes die verschiedenen Bodensensoren installiert, sowie Modelle und Entscheidungsalgorithmen zur Steuerung der D{\"u}ngung und dementsprechend Verbesserung der Bodenfunktionen erstellt werden. Ziel der vorliegenden Arbeit ist die Grundlagenuntersuchung und Entwicklung einer robusten Online-Analyse mittels Energie-dispersiver R{\"o}ntgenfluoreszenzspektroskopie (EDRFA) zur Quantifizierung ausgew{\"a}hlter Makro- und Mikron{\"a}hrstoffe in B{\"o}den f{\"u}r eine kosteng{\"u}nstige und fl{\"a}chendeckende Kartierung von Ackerfl{\"a}chen. F{\"u}r die Entwicklung eines Online-Verfahrens wurde ein dem Stand der Technik entsprechender R{\"o}ntgenfluoreszenzmesskopf in Betrieb genommen und die dazugeh{\"o}rigen Ger{\"a}teparameter auf die Matrix Boden optimiert. Die Bestimmung der analytischen Qualit{\"a}ts-merkmale wie Pr{\"a}zision und Nachweisgrenzen fand f{\"u}r eine Auswahl an N{\"a}hrelementen von Aluminium bis Zink statt. Um eine m{\"o}glichst Matrix-angepasste Kalibrierung zu erhalten, wurde sowohl mit zertifizierten Referenzmaterialien (CRM), als auch mit Ackerb{\"o}den kalibriert. Da einer der gr{\"o}ßten Nachteile der R{\"o}ntgenfluoreszenzanalyse die Beeinflussung durch Matrixeffekte ist, wurde neben der klassischen univariaten Datenauswertung auch die chemometrische multivariate Methode der Partial Least Squares Regression (PLSR) eingesetzt. Die PLSR bietet dabei den Vorteil, Matrixeffekte auszugleichen, wodurch robustere Kalibriermodelle erhalten werden k{\"o}nnen. Zus{\"a}tzlich wurde eine Hauptkomponentenanalyse (PCA) durchgef{\"u}hrt, um Gemeinsamkeiten und Ausreißer innerhalb des Probensets zu identifizieren. Es zeigte sich, dass eine Klassifizierung der B{\"o}den anhand ihrer Textur Sand, Schluff, Lehm und Ton m{\"o}glich ist. Aufbauend auf den Ergebnissen idealer Bodenproben (zu Tabletten gepresste luftgetrocknete Proben mit Korngr{\"o}ßen < 0,5 mm) wurde im Verlauf dieser Arbeit die Probenvorbereitung immer weiter reduziert und der Einfluss verschiedener Kenngr{\"o}ßen untersucht. Diese Einflussfaktoren k{\"o}nnen die Dichte und die Homogenit{\"a}t der Probe, sowie Korngr{\"o}ßeneffekte und die Feuchtigkeit sein. Anhand des RMSE (Wurzel der mittleren Fehlerquadratsumme) und unter Ber{\"u}cksichtigung der Residuen werden die jeweils erstellten Kalibriermodelle miteinander verglichen. Um die G{\"u}te der Modelle zu bewerten, wurden diese mit einem Testset validiert. Hierf{\"u}r standen 662 Bodenproben von 15 verschiedenen Standorten in Deutschland zur Verf{\"u}gung. Da die Ergebnisse an gepressten Tabletten f{\"u}r die Elemente Al, Si, K, Ca, Ti, Mn, Fe und Zn den Anforderungen f{\"u}r eine sp{\"a}tere Online-Analyse entsprechen, wurden im weiteren Verlauf dieser Arbeit Kalibriermodelle mit losen Bodenproben erstellt. Auch hier konnten gute Ergebnisse durch ausreichende Nachweisgrenzen und eine niedrige gemittelte Messabweichung bei der Vorhersage unbekannter Testproben erzielt werden. Es zeigte sich, dass die Vorhersagef{\"a}higkeit mit der multivariaten PLSR besser ist als mit der univariaten Datenauswertung, insbesondere f{\"u}r die Elemente Mn und Zn. Der untersuchte Einfluss der Feuchtigkeit und der Korngr{\"o}ßen auf die Quantifizierung der Elementgehalte war vor allem bei leichteren Elementen deutlich zu sehen. Es konnte schließlich eine multivariate Kalibrierung unter Ber{\"u}cksichtigung dieser Faktoren f{\"u}r die Elemente Al bis Zn erstellt werden, so dass ein Einsatz an B{\"o}den auf dem Acker m{\"o}glich sein sollte. Eine h{\"o}here Messunsicherheit muss dabei einkalkuliert werden. F{\"u}r eine sp{\"a}tere Probennahme auf dem Feld wurde zudem der Unterschied zwischen statischen und dynamischen Messungen betrachtet, wobei sich zeigte, dass beide Varianten genutzt werden k{\"o}nnen. Zum Abschluss wurde der hier eingesetzte Sensor mit einem kommerziell erh{\"a}ltlichen Hand-Ger{\"a}t auf sein Quantifizierungspotential hin verglichen. Der Sensor weist anhand seiner Ergebnisse ein großes Potential als Online-Sensor f{\"u}r die Messplattform auf. Die Ergebnisse unter Laborbedingungen zeigen, dass eine robuste Analyse Ackerb{\"o}den unter Ber{\"u}cksichtigung der Einflussfaktoren m{\"o}glich ist.},
  language  = {de}
}
@phdthesis{Caprioglio2020,
  author    = {Caprioglio, Pietro},
  title     = {Non-radiative recombination losses in perovskite solar cells},
  doi       = {10.25932/publishup-47763},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-477630},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vi, 242},
  year      = {2020},
  abstract  = {In the last decade the photovoltaic research has been preponderantly overturned by the arrival of metal halide perovskites. The introduction of this class of materials in the academic research for renewable energy literally shifted the focus of a large number of research groups and institutions. The attractiveness of halide perovskites lays particularly on their skyrocketing efficiencies and relatively simple and cheap fabrication methods. Specifically, the latter allowed for a quick development of this research in many universities and institutes around the world at the same time. The outcome has been a fast and beneficial increase in knowledge with a consequent terrific improvement of this new technology. On the other side, the enormous amount of research promoted an immense outgrowth of scientific literature, perpetually published. Halide perovskite solar cells are now effectively competing with other established photovoltaic technologies in terms of power conversion efficiencies and production costs. Despite the tremendous improvement, a thorough understanding of the energy losses in these systems is of imperative importance to unlock the full thermodynamic potential of this material. This thesis focuses on the understanding of the non-radiative recombination processes in the neat perovskite and in complete devices. Specifically, photoluminescence quantum yield (PLQY) measurements were applied to multilayer stacks and cells under different illumination conditions to accurately determine the quasi-Fermi levels splitting (QFLS) in the absorber, and compare it with the external open-circuit voltage of the device (V_OC). Combined with drift-diffusion simulations, this approach allowed us to pinpoint the sites of predominant recombination, but also to investigate the dynamics of the underlying processes. As such, the internal and external ideality factors, associated to the QFLS and V_OC respectively, are studied with the aim of understanding the type of recombination processes taking place in the multilayered architecture of the device. Our findings highlight the failure of the equality between QFLS and V_OC in the case of strong interface recombination, as well as the detrimental effect of all commonly used transport layers in terms of V_OC losses. In these regards, we show how, in most perovskite solar cells, different recombination processes can affect the internal QFLS and the external V_OC and that interface recombination dictates the V_OC losses. This line of arguments allowed to rationalize that, in our devices, the external ideality factor is completely dominated by interface recombination, and that this process can alone be responsible for values of the ideality factor between 1 and 2, typically observed in perovskite solar cells. Importantly, our studies demonstrated how strong interface recombination can lower the ideality factor towards values of 1, often misinterpreted as pure radiative second order recombination. As such, a comprehensive understanding of the recombination loss mechanisms currently limiting the device performance was achieved. In order to reach the full thermodynamic potential of the perovskite absorber, the interfaces of both the electron and hole transport layers (ETL/HTL) must be properly addressed and improved. From here, the second part of the research work is devoted on reducing the interfacial non-radiative energy losses by optimizing the structure and energetics of the relevant interface in our solar cell devices, with the aim of bringing their quasi-Fermi level splitting closer to its radiative limit. As such, the interfaces have been carefully addressed and optimized with different methodologies. First, a small amount of Sr is added into the perovskite precursor solution with the effect of effectively reducing surface and interface recombination. In this case, devices with V_OC up to 1.23 V were achieved and the energy losses were minimized to as low as 100 meV from the radiative limit of the material. Through a combination of different methods, we showed that these improvements are related to a strong n-type surface doping, which repels the holes in the perovskite from the surface and the interface with the ETL. Second, a more general device improvement was achieved by depositing a defect-passivating poly(ionic-liquid) layer on top of the perovskite absorber. The resulting devices featured a concomitant improvement of the V_OC and fill factor, up to 1.17 V and 83\% respectively, reaching efficiency as high as 21.4\%. Moreover, the protecting polymer layer helped to enhance the stability of the devices under prolonged maximum power point tracking measurements. Lastly, PLQY measurements are used to investigate the recombination mechanisms in halide-segregated large bandgap perovskite materials. Here, our findings showed how few iodide-rich low-energy domains act as highly efficient radiative recombination centers, capable of generating PLQY values up to 25\%. Coupling these results with a detailed microscopic cathodoluminescence analysis and absorption profiles allowed to demonstrate how the emission from these low energy domains is due to the trapping of the carriers photogenerated in the Br-rich high-energy domains. Thereby, the strong implications of this phenomenon are discussed in relation to the failure of the optical reciprocity between absorption and emission and on the consequent applicability of the Shockley-Queisser theory for studying the energy losses such systems. In conclusion, the identification and quantification of the non-radiative QFLS and V_OC losses provided a base knowledge of the fundamental limitation of perovskite solar cells and served as guidance for future optimization and development of this technology. Furthermore, by providing practical examples of solar cell improvements, we corroborated the correctness of our fundamental understanding and proposed new methodologies to be further explored by new generations of scientists.},
  language  = {en}
}
@phdthesis{Chandra2020,
  author    = {Chandra, Johan},
  title     = {The role of the oculomotor control in eye movements during reading},
  doi       = {10.25932/publishup-47593},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-475930},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiii, 115},
  year      = {2020},
  abstract  = {Most reading theories assume that readers aim at word centers for optimal information processing. During reading, saccade targeting turns out to be imprecise: Saccades' initial landing positions often miss the word centers and have high variance, with an additional systematic error that is modulated by the distance from the launch site to the center of the target word. The performance of the oculomotor system, as reflected in the statistics of within-word landing positions, turns out to be very robust and mostly affected by the spatial information during reading. Hence, it is assumed that the saccade generation is highly automated. The main goal of this thesis is to explore the performance of the oculomotor system under various reading conditions where orthographic information and the reading direction were manipulated. Additionally, the challenges in understanding the eye movement data to represent the oculomotor process during reading are addressed. Two experimental studies and one simulation study were conducted for this thesis, which resulted in the following main findings: (i) Reading texts with orthographic manipulations leads to specific changes in the eye movement patterns, both in temporal and spatial measures. The findings indicate that the oculomotor control of eye movements during reading is dependent on reading conditions (Chapter 2 \& 3). (ii) Saccades' accuracy and precision can be simultaneously modulated under reversed reading condition, supporting the assumption that the random and systematic oculomotor errors are not independent. By assuming that readers increase the precision of sensory observation while maintaining the learned prior knowledge when reading direction was reversed, a process-oriented Bayesian model for saccade targeting can account for the simultaneous reduction of oculomotor errors (Chapter 2). (iii) Plausible parameter values serving as proxies for the intended within-word landing positions can be estimated by using the maximum a posteriori estimator from Bayesian inference. Using the mean value of all observations as proxies is insufficient for studies focusing on the launch-site effect because the method exhibits the strongest bias when estimating the size of the effect. Mislocated fixations remain a challenge for the currently known estimation methods, especially when the systematic oculomotor error is large (Chapter 4). The results reported in this thesis highlight the role of the oculomotor system, together with underlying cognitive processes, in eye movements during reading. The modulation of oculomotor control can be captured through a precise analysis of landing positions.},
  language  = {en}
}
@phdthesis{Chao2020,
  author    = {Chao, Madlen},
  title     = {Entwicklung und Validierung eines Online-LIBS-Verfahrens f{\"u}r die Bestimmung von N{\"a}hrelementen in B{\"o}den},
  doi       = {10.25932/publishup-47677},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-476772},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XII, 130},
  year      = {2020},
  abstract  = {In den letzten Jahrzehnten ist die Nachfrage nach kosteng{\"u}nstigen und fl{\"a}chendeckenden Kartierungsm{\"o}glichkeiten im Hinblick auf eine ertragssteigernde und umweltfreundlichere Bewirtschaftung von landwirtschaftlichen Nutzfl{\"a}chen stark gestiegen. Hierf{\"u}r eignen sich spektroskopische Methoden wie die R{\"o}ntgenfluoreszenzanalyse (RFA), Raman- und Gammaspektroskopie sowie die laserinduzierte Plasmaspektroskopie (LIBS). In Abh{\"a}ngigkeit von der Funktionsweise der jeweiligen Methoden werden Informationen zu verschiedensten Bodeneigenschaften wie N{\"a}hrelementgehalt, Textur und pH-Wert erhalten. Ziel dieser Arbeit ist die Entwicklung eines Online-LIBS-Verfahrens zur N{\"a}hrelementbestimmmung und Kartierung von Ackerfl{\"a}chen. Die LIBS ist eine schnelle und simultane Multielementanalyse bei der durch das Fokussieren eines hochenergetischen Laserpulses Probenmaterial von der Probenoberfl{\"a}che ablatiert wird und in ein Plasma {\"u}berf{\"u}hrt wird. Beim Abk{\"u}hlen des Plasmas wird Strahlung emittiert, welche R{\"u}ckschl{\"u}sse {\"u}ber die elementare Zusammensetzung der Probe gibt. Diese Arbeit ist im Teilprojekt I4S (Intelligenz f{\"u}r B{\"o}den) im Forschungsprogramm BonaRes (Boden als nachhaltige Ressource f{\"u}r die Bio{\"o}konomie) des Bundesministerium f{\"u}r Bildung und Forschung (BMBF) entstanden. Es wurden insgesamt 651 Bodenproben von verschiedenen Test-Agrarfl{\"a}chen unterschiedlichster Standorte Deutschlands gemessen, ausgewertet und zu Validierungszwecken mit entsprechender Referenzanalytik wie die Optische Emissionsspektroskopie mittels induktiv gekoppeltem Plasma (ICP-OES) und die wellenl{\"a}ngendispersive R{\"o}ntgenfluoreszenzanalyse (WDRFA) charakterisiert. F{\"u}r die Quantifizierung wurden zun{\"a}chst die Messparameter des LIBS-Systems auf die Bodenmatrix optimiert und f{\"u}r die Elemente geeignete Linien ausgew{\"a}hlt sowie deren Nachweisgrenzen bestimmt. Es hat sich gezeigt, dass eine absolute Quantifizierung basierend auf einem univariaten Ansatz aufgrund der starken Matrixeffekte und der schlechten Reproduzierbarkeit des Plasmas nur eingeschr{\"a}nkt m{\"o}glich ist. Bei Verwendung eines multivariaten Ansatz wie der Partial Least Squares Regression (PLSR) f{\"u}r die Kalibrierung konnten f{\"u}r die N{\"a}hrelemente im Vergleich zur univariaten Variante Analyseergebnisse mit h{\"o}herer G{\"u}te und geringeren Messunsicherheiten ermittelt werden. Die Untersuchungen haben gezeigt, dass das multivariate Modell weiter verbessert werden kann, indem mit einer Vielzahl von gut analysierten B{\"o}den verschiedener Standorte, Bodenarten und einem breiten Gehaltsbereich kalibriert wird. Mithilfe der Hauptkomponentenanalyse (PCA) wurde eine Klassifizierung der B{\"o}den nach der Textur realisiert. Weiterhin wurde auch eine Kalibrierung mit losem Bodenmaterial erstellt. Trotz der Signalabnahme konnten f{\"u}r die verschiedenen N{\"a}hrelemente Kalibriergeraden mit ausreichender, analytischer G{\"u}te erstellt werden. F{\"u}r den Einsatz auf dem Acker wurde außerdem der Einfluss von Korngr{\"o}ße und Feuchtigkeit auf das LIBS-Signal untersucht. Die unterschiedlichen Korngr{\"o}ßen haben nur einen geringen Einfluss auf das LIBS-Signal und das Kalibriermodell l{\"a}sst sich durch entsprechende Proben leicht anpassen. Dagegen ist der Einfluss der Feuchtigkeit deutlich st{\"a}rker und h{\"a}ngt stark von der Bodenart ab, sodass f{\"u}r jede Bodenart ein separates Kalibriermodell f{\"u}r verschiedene Feuchtigkeitsgehalte erstellt werden muss. Mithilfe der PCA kann der Feuchtigkeitsgehalt im Boden grob abgesch{\"a}tzt werden und die entsprechende Kalibrierung ausgew{\"a}hlt werden. Diese Arbeit liefert essentielle Informationen f{\"u}r eine Echtzeit-Analyse von N{\"a}hrelementen auf dem Acker mittels LIBS und leistet einen wichtigen Beitrag zu einer fortschrittlichen und zukunftsf{\"a}higen Nutzung von Ackerfl{\"a}chen.},
  language  = {de}
}
@phdthesis{Christ2020,
  author    = {Christ, Simon},
  title     = {Morphological transitions of vesicles exposed to nonuniform spatio-temporal conditions},
  doi       = {10.25932/publishup-48078},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-480788},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 105},
  year      = {2020},
  abstract  = {Giant unilamellar vesicles are an important tool in todays experimental efforts to understand the structure and behaviour of biological cells. Their simple structure allows the isolation of the physical elastic properties of the lipid membrane. A central physical property is the bending energy of the membrane, since the many different shapes of giant vesicles can be obtained by finding the minimum of the bending energy. In the spontaneous curvature model the bending energy is a function of the bending rigidity as well as the mean curvature and an additional parameter called the spontaneous curvature, which describes an internal preference of the lipid-bilayer to bend towards one side or the other. The spontaneous and mean curvature are local properties of the membrane. Additional constraints arise from the conservation of the membrane surface area and the enclosed volume, which are global properties. In this thesis the spontaneous curvature model is used to explain the experimental observation of a periodic shape oscillation of a giant unilamellar vesicle that was filled with a protein complex that periodically binds to and unbinds from the membrane. By assuming that the binding of the proteins to the membrane induces a change in the spontaneous curvature the experimentally observed shapes could successfully be explained. This involves the numerical solution of the differential equations as obtained from the minimization of the bending energy respecting the area and volume constraints, the so called shape equations. Vice versa this approach can be used to estimate the spontaneous curvature from experimentally measurable quantities. The second topic of this thesis is the analysis of concentration gradients in rigid conic membrane compartments. Gradients of an ideal gas due to gravity and gradients generated by the directed stochastic movement of molecular motors along a microtubulus were considered. It was possible to calculate the free energy and the bending energy analytically for the ideal gas. In the case of the non-equilibrium system with molecular motors, the characteristic length of the density profile, the jam-length, and its dependency on the opening angle of the conic compartment have been calculated in the mean-field limit. The mean field results agree qualitatively with stochastic particle simulations.},
  language  = {en}
}
@phdthesis{Ciaccio2020,
  author    = {Ciaccio, Laura Anna},
  title     = {Prefixed words in morphological processing and morphological impairments},
  doi       = {10.25932/publishup-48465},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-484651},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 276},
  year      = {2020},
  abstract  = {In recent years, a substantial number of psycholinguistic studies and of studies on acquired language impairments have investigated the case of morphologically complex words. These have provided evidence for what is known as 'morphological decomposition', i.e. a mechanism that decomposes complex words into their constituent morphemes during online processing. This is believed to be a fundamental, possibly universal mechanism of morphological processing, operating irrespective of a word's specific properties. However, current accounts of morphological decomposition are mostly based on evidence from suffixed words and compound words, while prefixed words have been comparably neglected. At the same time, it has been consistently observed that, across languages, prefixed words are less widespread than suffixed words. This cross-linguistic preference for suffixing morphology has been claimed to be grounded in language processing and language learning mechanisms. This would predict differences in how prefixed words are processed and therefore also affected in language impairments, challenging the predictions of the major accounts of morphological decomposition. Against this background, the present thesis aims at reducing the gap between the accounts of morphological decomposition and the accounts of the suffixing preference, by providing a thorough empirical investigation of prefixed words. Prefixed words are examined in three different domains: (i) visual word processing in native speakers; (ii) visual word processing in non-native speakers; (iii) acquired morphological impairments. The processing studies employ the masked priming paradigm, tapping into early stages of visual word recognition. Instead, the studies on morphological impairments investigate the errors produced in reading aloud tasks. As for native processing, the present work first focuses on derivation (Publication I), specifically investigating whether German prefixed derived words, both lexically restricted (e.g. inaktiv 'inactive') and unrestricted (e.g. unsauber 'unclean') can be efficiently decomposed. I then present a second study (Publication II) on a Bantu language, Setswana, which offers the unique opportunity of testing inflectional prefixes, and directly comparing priming with prefixed inflected primes (e.g. dikgeleke 'experts') to priming with prefixed derived primes (e.g. bokgeleke 'talent'). With regard to non-native processing (Publication I), the priming effects obtained from the lexically restricted and unrestricted prefixed derivations in native speakers are additionally compared to the priming effects obtained in a group of non-native speakers of German. Finally, in the two studies on acquired morphological impairments, the thesis investigates whether prefixed derived words yield different error patterns than suffixed derived words (Publication III and IV). For native speakers, the results show evidence for morphological decomposition of both types of prefixed words, i.e. lexically unrestricted and restricted derivations, as well as of prefixed inflected words. Furthermore, non-native speakers are also found to efficiently decompose prefixed derived words, with parallel results to the group of native speakers. I therefore conclude that, for the early stages of visual word recognition, the relative position of stem and affix in prefixed versus suffixed words does not affect how efficiently complex words are decomposed, either in native or in non-native processing. In the studies on acquired language impairments, instead, prefixes are consistently found to be more impaired than suffixes. This is explained in terms of a learnability disadvantage for prefixed words, which may cause weaker representations of the information encoded in affixes when these precede the stem (prefixes) as compared to when they follow it (suffixes). Based on the impairment profiles of the individual participants and on the nature of the task, this dissociation is assumed to emerge from later processing stages than those that are tapped into by masked priming. I therefore conclude that the different characteristics of prefixed and suffixed words do come into play at later processing stages, during which the lexical-semantic information contained in the different constituent morphemes is processed. The findings presented in the four manuscripts significantly contribute to our current understanding of the mechanisms involved in processing prefixed words. Crucially, the thesis constrains the processing disadvantage for prefixed words to later processing stages, thereby suggesting that theories trying to establish links between language universals and processing mechanisms should more carefully consider the different stages involved in language processing and what factors are relevant for each specific stage.},
  language  = {en}
}
@phdthesis{Crawford2020,
  author    = {Crawford, Michael Scott},
  title     = {Using individual-based modeling to understand grassland diversity and resilience in the Anthropocene},
  doi       = {10.25932/publishup-47941},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-479414},
  school      = {Universit{\"a}t Potsdam},
  pages     = {174},
  year      = {2020},
  abstract  = {The world's grassland systems are increasingly threatened by anthropogenic change. Susceptible to a variety of different stressors, from land-use intensification to climate change, understanding the mechanisms driving the maintenance of these systems' biodiversity and stability, and how these mechanisms may shift under human-mediated disturbance, is thus critical for successfully navigating the next century. Within this dissertation, I use an individual-based and spatially-explicit model of grassland community assembly (IBC-grass) to examine several processes, thought key to understanding their biodiversity and stability and how it changes under stress. In the first chapter of my thesis, I examine the conditions under which intraspecific trait variation influences the diversity of simulated grassland communities. In the second and third chapters of my thesis, I shift focus towards understanding how belowground herbivores influence the stability of these grassland systems to either a disturbance that results in increased, stochastic, plant mortality, or eutrophication. Intraspecific trait variation (ITV), or variation in trait values between individuals of the same species, is fundamental to the structure of ecological communities. However, because it has historically been difficult to incorporate into theoretical and statistical models, it has remained largely overlooked in community-level analyses. This reality is quickly shifting, however, as a consensus of research suggests that it may compose a sizeable proportion of the total variation within an ecological community and that it may play a critical role in determining if species coexist. Despite this increasing awareness that ITV matters, there is little consensus of the magnitude and direction of its influence. Therefore, to better understand how ITV changes the assembly of grassland communities, in the first chapter of my thesis, I incorporate it into an established, individual-based grassland community model, simulating both pairwise invasion experiments as well as the assembly of communities with varying initial diversities. By varying the amount of ITV in these species' functional traits, I examine the magnitude and direction of ITV's influence on pairwise invasibility and community coexistence. During pairwise invasion, ITV enables the weakest species to more frequently invade the competitively superior species, however, this influence does not generally scale to the community level. Indeed, unless the community has low alpha- and beta- diversity, there will be little effect of ITV in bolstering diversity. In these situations, since the trait axis is sparsely filled, the competitively inferior may suffer less competition and therefore ITV may buffer the persistence and abundance of these species for some time. In the second and third chapters of my thesis, I model how one of the most ubiquitous trophic interactions within grasslands, herbivory belowground, influences their diversity and stability. Until recently, the fundamental difficulty in studying a process within the soil has left belowground herbivory "out of sight, out of mind." This dilemma presents an opportunity for simulation models to explore how this understudied process may alter community dynamics. In the second chapter of my thesis, I implement belowground herbivory - represented by the weekly removal of plant biomass - into IBC-grass. Then, by introducing a pulse disturbance, modelled as the stochastic mortality of some percentage of the plant community, I observe how the presence of belowground herbivores influences the resistance and recovery of Shannon diversity in these communities. I find that high resource, low diversity, communities are significantly more destabilized by the presence of belowground herbivores after disturbance. Depending on the timing of the disturbance and whether the grassland's seed bank persists for more than one season, the impact of the disturbance - and subsequently the influence of the herbivores - can be greatly reduced. However, because human-mediated eutrophication increases the amount of resources in the soil, thus pressuring grassland systems, our results suggest that the influence of these herbivores may become more important over time. In the third chapter of my thesis, I delve further into understanding the mechanistic underpinnings of belowground herbivores on the diversity of grasslands by replicating an empirical mesocosm experiment that crosses the presence of herbivores above- and below-ground with eutrophication. I show that while aboveground herbivory, as predicted by theory and frequently observed in experiments, mitigates the impact of eutrophication on species diversity, belowground herbivores counterintuitively reduce biodiversity. Indeed, this influence positively interacts with the eutrophication process, amplifying its negative impact on diversity. I discovered the mechanism underlying this surprising pattern to be that, as the herbivores consume roots, they increase the proportion of root resources to root biomass. Because root competition is often symmetric, herbivory fails to mitigate any asymmetries in the plants' competitive dynamics. However, since the remaining roots have more abundant access to resources, the plants' competition shifts aboveground, towards asymmetric competition for light. This leads the community towards a low-diversity state, composed of mostly high-performance, large plant species. We further argue that this pattern will emerge unless the plants' root competition is asymmetric, in which case, like its counterpart aboveground, belowground herbivory may buffer diversity by reducing this asymmetry between the competitively superior and inferior plants. I conclude my dissertation by discussing the implications of my research on the state of the art in intraspecific trait variation and belowground herbivory, with emphasis on the necessity of more diverse theory development in the study of these fundamental interactions. My results suggest that the influence of these processes on the biodiversity and stability of grassland systems is underappreciated and multidimensional, and must be thoroughly explored if researchers wish to predict how the world's grasslands will respond to anthropogenic change. Further, should researchers myopically focus on understanding central ecological interactions through only mathematically tractable analyses, they may miss entire suites of potential coexistence mechanisms that can increase the coviability of species, potentially leading to coexistence over ecologically-significant timespans. Individual-based modelling, therefore, with its focus on individual interactions, will prove a critical tool in the coming decades for understanding how local interactions scale to larger contexts, and how these interactions shape ecological communities and further predicting how these systems will change under human-mediated stress.},
  language  = {en}
}
@phdthesis{Dahlke2020,
  author    = {Dahlke, Sandro},
  title     = {Rapid climate changes in the arctic region of Svalbard},
  doi       = {10.25932/publishup-44554},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445542},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xv, 123},
  year      = {2020},
  abstract  = {Over the last decades, the Arctic regions of the earth have warmed at a rate 2-3 times faster than the global average- a phenomenon called Arctic Amplification. A complex, non-linear interplay of physical processes and unique pecularities in the Arctic climate system is responsible for this, but the relative role of individual processes remains to be debated. This thesis focuses on the climate change and related processes on Svalbard, an archipelago in the North Atlantic sector of the Arctic, which is shown to be a "hotspot" for the amplified recent warming during winter. In this highly dynamical region, both oceanic and atmospheric large-scale transports of heat and moisture interfere with spatially inhomogenous surface conditions, and the corresponding energy exchange strongly shapes the atmospheric boundary layer. In the first part, Pan-Svalbard gradients in the surface air temperature (SAT) and sea ice extent (SIE) in the fjords are quantified and characterized. This analysis is based on observational data from meteorological stations, operational sea ice charts, and hydrographic observations from the adjacent ocean, which cover the 1980-2016 period. It is revealed that typical estimates of SIE during late winter range from 40-50\% (80-90\%) in the western (eastern) parts of Svalbard. However, strong SAT warming during winter of the order of 2-3K per decade dictates excessive ice loss, leaving fjords in the western parts essentially ice-free in recent winters. It is further demostrated that warm water currents on the west coast of Svalbard, as well as meridional winds contribute to regional differences in the SIE evolution. In particular, the proximity to warm water masses of the West Spitsbergen Current can explain 20-37\% of SIE variability in fjords on west Svalbard, while meridional winds and associated ice drift may regionally explain 20-50\% of SIE variability in the north and northeast. Strong SAT warming has overruled these impacts in recent years, though. In the next part of the analysis, the contribution of large-scale atmospheric circulation changes to the Svalbard temperature development over the last 20 years is investigated. A study employing kinematic air-back trajectories for Ny-{\AA}lesund reveals a shift in the source regions of lower-troposheric air over time for both the winter and the summer season. In winter, air in the recent decade is more often of lower-latitude Atlantic origin, and less frequent of Arctic origin. This affects heat- and moisture advection towards Svalbard, potentially manipulating clouds and longwave downward radiation in that region. A closer investigation indicates that this shift during winter is associated with a strengthened Ural blocking high and Icelandic low, and contributes about 25\% to the observed winter warming on Svalbard over the last 20 years. Conversely, circulation changes during summer include a strengthened Greenland blocking high which leads to more frequent cold air advection from the central Arctic towards Svalbard, and less frequent air mass origins in the lower latitudes of the North Atlantic. Hence, circulation changes during winter are shown to have an amplifying effect on the recent warming on Svalbard, while summer circulation changes tend to mask warming. An observational case study using upper air soundings from the AWIPEV research station in Ny-{\AA}lesund during May-June 2017 underlines that such circulation changes during summer are associated with tropospheric anomalies in temperature, humidity and boundary layer height. In the last part of the analysis, the regional representativeness of the above described changes around Svalbard for the broader Arctic is investigated. Therefore, the terms in the diagnostic temperature equation in the Arctic-wide lower troposphere are examined for the Era-Interim atmospheric reanalysis product. Significant positive trends in diabatic heating rates, consistent with latent heat transfer to the atmosphere over regions of increasing ice melt, are found for all seasons over the Barents/Kara Seas, and in individual months in the vicinity of Svalbard. The above introduced warm (cold) advection trends during winter (summer) on Svalbard are successfully reproduced. Regarding winter, they are regionally confined to the Barents Sea and Fram Strait, between 70°-80°N, resembling a unique feature in the whole Arctic. Summer cold advection trends are confined to the area between eastern Greenland and Franz Josef Land, enclosing Svalbard.},
  language  = {en}
}
@phdthesis{DeVeaughGeiss2020,
  author    = {De Veaugh-Geiss, Joseph P.},
  title     = {Cleft exhaustivity},
  doi       = {10.25932/publishup-44642},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-446421},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 243},
  year      = {2020},
  abstract  = {In this dissertation a series of experimental studies are presented which demonstrate that the exhaustive inference of focus-background it-clefts in English and their cross-linguistic counterparts in Akan, French, and German is neither robust nor systematic. The inter-speaker and cross-linguistic variability is accounted for with a discourse-pragmatic approach to cleft exhaustivity, in which -- following Pollard \& Yasavul 2016 -- the exhaustive inference is derived from an interaction with another layer of meaning, namely, the existence presupposition encoded in clefts.},
  language  = {en}
}
@phdthesis{Dehm2020,
  author    = {Dehm, Daniel},
  title     = {Development of concepts for the genomic mining of novel secondary metabolites in symbiotic cyanobacteria},
  doi       = {10.25932/publishup-47834},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-478342},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VIII, 122, XII},
  year      = {2020},
  abstract  = {Naturstoffe sind seit der goldenen {\"A}ra der Antibiotika von immer gr{\"o}ßerem Interesse, sowohl f{\"u}r die Grundlagenforschung als auch die Angewandten Wissenschaften, da sie die Hauptquelle f{\"u}r neuartige Pharmazeutika mit starken antibiotischen, anti-entz{\"u}ndlichen und Antitumor-Aktivit{\"a}ten darstellen. Neben den technologischen Fortschritten im Bereich der Hochdurchsatz Genomsequenzierung und dem verbesserten Verst{\"a}ndnis des modularen Aufbaus der Biosynthesewege von Sekund{\"a}rmetaboliten, kam es auch zu einem Wechsel vom labor-gest{\"u}tzten Screening aktiver Zellextrakte hin zum Algorithmen-basierten in silico Screening nach neuen Naturstoff-Biosyntheseclustern. Obwohl die steigende Zahl verf{\"u}gbarer Genomsequenzen zeigte, dass nicht-ribosomale Peptid-Synthetasen (NRPS), Polyketid-Synthasen (PKS), und ribosomal synthetisierte und posttranslational modifizierte Peptide (RiPPs) ubiquit{\"a}r in allen Sparten des Lebens gefunden werden k{\"o}nnen, so zeigen einige Phyla wie Actinobakterien oder Cyanobakterien eine besonders hohe Dichte an Sekund{\"a}rmetabolitclustern. Der fakultativ symbiotische, N2-fixierende Modellorganismus N. punctiforme PCC73102 ist ein terrestrisches typ-IV Cyanobakterium, welches nicht nur einen besonders hohen Anteil seines Genoms der Produktion von Sekund{\"a}rmetaboliten widmet, sondern zus{\"a}tzlich noch genetisch modifizierbar ist. Eine AntiSMASH Analyse des Genoms zeigte, dass N. punctiforme insgesamt sechzehn potentielle Sekund{\"a}rmetabolitcluster besitzt, von denen aber bis heute nur zweien ein spezifisches Produkt zugewiesen werden konnte. Das macht N. punctiforme zu einem perfekten Testorganismus f{\"u}r die Entwicklung eines neuartigen kombinatorischen Genomic Mining Ansatzes zur Detektion von bislang unbeschriebenen Naturstoffen. Der neuartige Ansatz, der im Rahmen dieser Studie entwickelt wurde, stellt eine Kombination aus Genomic Mining, unabh{\"a}ngigen Monitoring-Techniken sowie modifizierten Kultivierungsbedingungen dar und f{\"u}hrte nicht nur zu neuen Erkenntnissen im Bereich cyanobakterieller Naturstoffsynthese, sondern letztlich auch zur Entdeckung eines neuen, von N. punctiforme produzierten, Naturstoffs. Die Herstellung und Untersuchung einer Reporterstamm Bibliothek, bestehend aus je einem CFP-produzierenden Transkriptionsreporter f{\"u}r jedes der sechzehn Sekund{\"a}rmetabolitcluster von N. punctiforme, zeigte, dass im Gegensatz zur Erwartung nicht alle Biosynthesecluster f{\"u}r die man kein Produkt nachweisen kann auch nicht exprimiert werden. Stattdessen konnten klar definierbare Expressionsmuster beschrieben werden, was deutlich machte, dass die Naturstoffproduktion einer engen Regulation unterliegt und nur ein kleiner Teil der Biosynthesecluster unter Standardbedingungen tats{\"a}chlich still sind. Dar{\"u}ber hinaus f{\"u}hrte die Erh{\"o}hung der Lichtintensit{\"a}t sowie der Kohlenstoffdioxid-Verf{\"u}gbarkeit zusammen mit der Kultivierung von N. punctiforme zu extrem hohen Zelldichten zu einer starken Erh{\"o}hung der gesamten metabolischen Aktivit{\"a}t des Organismus. N{\"a}here Untersuchungen der Zellextrakte dieser hoch-dichte Kultivierungen f{\"u}hrten letztlich zur Entdeckung einer neuartigen Gruppe von Microviridinen mit verl{\"a}ngerter Peptidsequenz, welche Microviridin N3-N9 genannt wurden. Sowohl die Kultivierung der Transkriptionsreporter als auch die RTqPCR-basierte Untersuchung der Transkriptionslevel der verschiedenen Biosynthesecluster zeigten, dass die hoch-Zelldichte Kultivierung von N. punctiforme zu einer Aktivierung von 50\% der vorhandenen Sekund{\"a}rmetabolitcluster f{\"u}hrt. Im Gegensatz zu dieser sehr breit-gef{\"a}cherten Aktivierung, f{\"u}hrt die Co-Kultivierung von N. punctiforme in chemischen oder physischen Kontakt zu einer N-gehungerten Wirtspflanze (Blasia pusilla) zu einer sehr spezifischen Aktivierung der RIPP4 und RiPP3 Biosynthesecluster. Obwohl dieser Effekt mittels verschiedener unabh{\"a}ngiger Methoden best{\"a}tigt werden konnte und trotz intensiver Analysebem{\"u}hungen, konnte jedoch keinem der beiden Cluster ein Produkt zugeordnet werden. Diese Studie stellt die erste weitreichende, systematische Analyse eines cyanobakteriellen Sekund{\"a}rmetaboloms durch einen kombinatorischen Ansatz aus Genomic Mining und unabh{\"a}ngigen Monitoring-Techniken dar und kann als neue strategische Herangehensweise f{\"u}r die Untersuchung anderer Organismen hinsichtlich ihrer Sekund{\"a}rmetabolit-Produktion dienen. Obwohl es bereits gut beschriebene einzelne Sekund{\"a}rmetabolite gibt, wie beispielweise den Zelldifferenzierungsfaktor PatS in Anabaena sp. PCC7120, so ist der Grad an Regulation der in dieser Studie gezeigt werden konnte bislang beispiellos und die Entschl{\"u}sselung dieser Mechanismen k{\"o}nnte die Entdeckung neuer Naturstoffe stark beschleunigen. Daneben lassen die Ergebnisse aber auch darauf schließen, dass die Induktion der Biosynthesewege nicht das eigentliche Problem darstellt, sondern vielmehr die verl{\"a}ssliche Detektion deren Produkte. Die Erarbeitung neuer Analytik-Strategien k{\"o}nnte somit auch einen deutlichen Einfluss auf die Geschwindigkeit der Entdeckung neuer Naturstoffe haben.},
  language  = {en}
}
@phdthesis{Dunsing2020,
  author    = {Dunsing, Valentin},
  title     = {Fluorescence fluctuation spectroscopy techniques to quantify molecular interactions and dynamics in complex biological systems},
  doi       = {10.25932/publishup-47849},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-478494},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VII, 164, XXV},
  year      = {2020},
  abstract  = {Living cells rely on transport and interaction of biomolecules to perform their diverse functions. A powerful toolbox to study these highly dynamic processes in the native environment is provided by fluorescence fluctuation spectroscopy (FFS) techniques. In more detail, FFS takes advantage of the inherent dynamics present in biological systems, such as diffusion, to infer molecular parameters from fluctuations of the signal emitted by an ensemble of fluorescently tagged molecules. In particular, two parameters are accessible: the concentration of molecules and their transit times through the observation volume. In addition, molecular interactions can be measured by analyzing the average signal emitted per molecule - the molecular brightness - and the cross-correlation of signals detected from differently tagged species. In the present work, several FFS techniques were implemented and applied in different biological contexts. In particular, scanning fluorescence correlation spectroscopy (sFCS) was performed to measure protein dynamics and interactions at the plasma membrane (PM) of cells, and number and brightness (N\&B) analysis to spatially map molecular aggregation. To account for technical limitations and sample related artifacts, e.g. detector noise, photobleaching, or background signal, several correction schemes were explored. In addition, sFCS was combined with spectral detection and higher moment analysis of the photon count distribution to resolve multiple species at the PM. Using scanning fluorescence cross-correlation spectroscopy and cross-correlation N\&B, the interactions of amyloid precursor-like protein 1 (APLP1), a synaptic membrane protein, were investigated. It is shown for the first time directly in living cells, that APLP1 undergoes specific interactions at cell-cell contacts. It is further demonstrated that zinc ions induce formation of large APLP1 clusters that enrich at contact sites and bind to clusters on the opposing cell. Altogether, these results provide direct evidence that APLP1 is a zinc ion dependent neuronal adhesion protein. In the context of APLP1, discrepancies of oligomeric state estimates were observed, which were attributed to non-fluorescent states of the chosen red fluorescent protein (FP) tag mCardinal (mCard). Therefore, multiple FPs and their performance in FFS based measurements of protein interactions were systematically evaluated. The study revealed superior properties of monomeric enhanced green fluorescent protein (mEGFP) and mCherry2. Furthermore, a simple correction scheme allowed unbiased in situ measurements of protein oligomerization by quantifying non-fluorescent state fractions of FP tags. The procedure was experimentally confirmed for biologically relevant protein complexes consisting of up to 12 monomers. In the last part of this work, fluorescence correlation spectroscopy (FCS) and single particle tracking (SPT) were used to characterize diffusive transport dynamics in a bacterial biofilm model. Biofilms are surface adherent bacterial communities, whose structural organization is provided by extracellular polymeric substances (EPS) that form a viscous polymer hydrogel. The presented study revealed a probe size and polymer concentration dependent (anomalous) diffusion hindrance in a reconstituted EPS matrix system caused by polymer chain entanglement at physiological concentrations. This result indicates a meshwork-like organization of the biofilm matrix that allows free diffusion of small particles, but strongly hinders diffusion of larger particles such as bacteriophages. Finally, it is shown that depolymerization of the matrix by phage derived enzymes rapidly facilitated free diffusion. In the context of phage infections, such enzymes may provide a key to evade trapping in the biofilm matrix and promote efficient infection of bacteria. In combination with phage application, matrix depolymerizing enzymes may open up novel antimicrobial strategies against multiresistant bacterial strains, as a promising, more specific alternative to conventional antibiotics.},
  language  = {en}
}
@phdthesis{Dyck2020,
  author    = {Dyck, Johannes},
  title     = {Verification of graph transformation systems with k-inductive invariants},
  doi       = {10.25932/publishup-44274},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-442742},
  school      = {Universit{\"a}t Potsdam},
  pages     = {X, 364},
  year      = {2020},
  abstract  = {With rising complexity of today's software and hardware systems and the hypothesized increase in autonomous, intelligent, and self-* systems, developing correct systems remains an important challenge. Testing, although an important part of the development and maintainance process, cannot usually establish the definite correctness of a software or hardware system - especially when systems have arbitrarily large or infinite state spaces or an infinite number of initial states. This is where formal verification comes in: given a representation of the system in question in a formal framework, verification approaches and tools can be used to establish the system's adherence to its similarly formalized specification, and to complement testing. One such formal framework is the field of graphs and graph transformation systems. Both are powerful formalisms with well-established foundations and ongoing research that can be used to describe complex hardware or software systems with varying degrees of abstraction. Since their inception in the 1970s, graph transformation systems have continuously evolved; related research spans extensions of expressive power, graph algorithms, and their implementation, application scenarios, or verification approaches, to name just a few topics. This thesis focuses on a verification approach for graph transformation systems called k-inductive invariant checking, which is an extension of previous work on 1-inductive invariant checking. Instead of exhaustively computing a system's state space, which is a common approach in model checking, 1-inductive invariant checking symbolically analyzes graph transformation rules - i.e. system behavior - in order to draw conclusions with respect to the validity of graph constraints in the system's state space. The approach is based on an inductive argument: if a system's initial state satisfies a graph constraint and if all rules preserve that constraint's validity, we can conclude the constraint's validity in the system's entire state space - without having to compute it. However, inductive invariant checking also comes with a specific drawback: the locality of graph transformation rules leads to a lack of context information during the symbolic analysis of potential rule applications. This thesis argues that this lack of context can be partly addressed by using k-induction instead of 1-induction. A k-inductive invariant is a graph constraint whose validity in a path of k-1 rule applications implies its validity after any subsequent rule application - as opposed to a 1-inductive invariant where only one rule application is taken into account. Considering a path of transformations then accumulates more context of the graph rules' applications. As such, this thesis extends existing research and implementation on 1-inductive invariant checking for graph transformation systems to k-induction. In addition, it proposes a technique to perform the base case of the inductive argument in a symbolic fashion, which allows verification of systems with an infinite set of initial states. Both k-inductive invariant checking and its base case are described in formal terms. Based on that, this thesis formulates theorems and constructions to apply this general verification approach for typed graph transformation systems and nested graph constraints - and to formally prove the approach's correctness. Since unrestricted graph constraints may lead to non-termination or impracticably high execution times given a hypothetical implementation, this thesis also presents a restricted verification approach, which limits the form of graph transformation systems and graph constraints. It is formalized, proven correct, and its procedures terminate by construction. This restricted approach has been implemented in an automated tool and has been evaluated with respect to its applicability to test cases, its performance, and its degree of completeness.},
  language  = {en}
}
@phdthesis{Erler2020,
  author    = {Erler, Alexander},
  title     = {Entwicklung von online-Detektionsverfahren f{\"u}r landwirtschaftlich relevante Analyten},
  doi       = {10.25932/publishup-47340},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473406},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 123},
  year      = {2020},
  abstract  = {Die Entwicklung nachhaltiger Bewirtschaftungs- und Produktionsmethoden ist eine der zentralen Fragestellungen der modernen Agrarwirtschaft. Die vorliegende Arbeit besch{\"a}ftigt sich mit zwei Forschungsthemen, die das Konzept Nachhaltigkeit beinhalten. In beiden F{\"a}llen werden analytische Grundlagen f{\"u}r die Entwicklung entsprechender landwirtschaftlicher Arbeitsmethoden gelegt. Das erste Thema ist an den sogenannten Pr{\"a}zisionsackerbau angelehnt. Bei diesem wird die Bearbeitung von Agrarfl{\"a}chen ortsabh{\"a}ngig ausgef{\"u}hrt. Das heißt, die Ausbringung von Saatgut, D{\"u}nger, Bew{\"a}sserung usw. richtet sich nach den Eigenschaften des jeweiligen Standortes und wird nicht pauschal gleichm{\"a}ßig {\"u}ber ein ganzes Feld verteilt. Voraussetzung hierf{\"u}r ist eine genaue Kenntnis der Bodeneigenschaften. In der vorliegenden Arbeit sollten diese Parameter mittels der analytischen Technik der Laser-induzierten Breakdown Spektroskopie (LIBS), die eine Form der Elementaranalyse darstellt, bestimmt werden. Bei den hier gesuchten Bodeneigenschaften handelte es sich um die Gehalte von N{\"a}hrstoffen sowie einige sekund{\"a}re Parameter wie den Humusanteil, den pH-Wert und den pflanzenverf{\"u}gbaren Anteil einzelner N{\"a}hrstoffe. Diese Eigenschaften wurden durch etablierte Referenzanalysen bestimmt. Darauf aufbauend wurden die Messergebnissen der LIBS-Untersuchungen durch verschiedene Methoden der sogenannten multivariaten Datenanalyse (MVA) ausgewertet. Daraus sollten Modelle zur Vorhersage der Bodenparameter in zuk{\"u}nftigen LIBS-Messungen erarbeitet werden. Die Ergebnisse dieser Arbeit zeigten, dass mit der Kombination von LIBS und MVA s{\"a}mtliche Bodenparameter erfolgreich vorhergesagt werden konnten. Dies beinhaltete sowohl die tats{\"a}chlich messbaren Elemente als auch die sekund{\"a}ren Eigenschaften, welche durch die MVA mit den Elementgehalten in Zusammenhang gebracht wurden. Das zweite Thema besch{\"a}ftigt sich mit der Vermeidung von Verlusten durch Sch{\"a}dlingsbefall bei der Getreidelagerung. Hier sollten mittels der Ionenmobilit{\"a}tsspektrometrie (IMS) Schimmelpilzkontaminationen detektiert werden. Dabei wurde nach den fl{\"u}chtigen Stoffwechselprodukten der Pilze gesucht. Die durch Referenzmessungen mit Massenspektrometern identifizierten Substanzen konnten durch IMS im Gasvolumen {\"u}ber den Proben, dem sogenannten Headspace, nachgewiesen werden. Dabei wurde nicht nur die Anwesenheit einer Kontamination festgestellt, sondern diese auch charakterisiert. Die freigesetzten Substanzen bildeten spezifische Muster, anhand derer die Pilze identifiziert werden konnten. Hier wurden sowohl verschiedene Gattungen als auch einzelne Arten unterschieden. Die Messungen fanden auf verschiedenen N{\"a}hrb{\"o}den statt um den Einfluss dieser auf die Stoffwechselprodukte zu beobachten. Auch die sekund{\"a}ren Stoffwechselprodukte der Schimmelpilze, die Mykotoxine, konnten durch IMS detektiert werden. Beide in dieser Arbeit vorgestellten Forschungsthemen konnten erfolgreich abgeschlossen werden. Sowohl LIBS als auch IMS erwiesen sich f{\"u}r den Nachweis der jeweiligen Analyten als geeignet, und der Einsatz moderner computergest{\"u}tzter Auswertemethoden erm{\"o}glichte die genaue Charakterisierung der gesuchten Parameter. Beide Techniken k{\"o}nnen in Form von mobilen Ger{\"a}ten verwendet werden und zeichnen sich durch eine schnelle und sichere Analyse aus. In Kombination mit entsprechenden Modellen der MVA sind damit alle Voraussetzungen f{\"u}r Vor-Ort-Untersuchungen und damit f{\"u}r den Einsatz in der Landwirtschaft erf{\"u}llt.},
  language  = {de}
}
@phdthesis{Folkertsma2020,
  author    = {Folkertsma, Remco},
  title     = {Evolutionary adaptation to climate in microtine mammals},
  doi       = {10.25932/publishup-47680},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-476807},
  school      = {Universit{\"a}t Potsdam},
  pages     = {135},
  year      = {2020},
  abstract  = {Understanding how organisms adapt to their local environment is a major focus of evolutionary biology. Local adaptation occurs when the forces of divergent natural selection are strong enough compared to the action of other evolutionary forces. An improved understanding of the genetic basis of local adaptation can inform about the evolutionary processes in populations and is of major importance because of its relevance to altered selection pressures due to climate change. So far, most insights have been gained by studying model organisms, but our understanding about the genetic basis of local adaptation in wild populations of species with little genomic resources is still limited. With the work presented in this thesis I therefore set out to provide insights into the genetic basis of local adaptation in populations of two voles species: the common vole (Microtus arvalis) and the bank vole (Myodes glareolus). Both voles species are small mammals, they have a high evolutionary potential compared to their dispersal capabilities and are thus likely to show genetic responses to local conditions, moreover, they have a wide distribution in which they experience a broad range of different environmental conditions, this makes them an ideal species to study local adaptation. The first study focused on producing a novel mitochondrial genome to facilitate further research in M. arvalis. To this end, I generated the first mitochondrial genome of M. arvalis using shotgun sequencing and an iterative mapping approach. This was subsequently used in a phylogenetic analysis that produced novel insights into the phylogenetic relationships of the Arvicolinae. The following two studies then focused on the genetic basis of local adaptation using ddRAD-sequencing data and genome scan methods. The first of these involved sequencing the genomic DNA of individuals from three low-altitude and three high-altitude M. arvalis study sites in the Swiss Alps. High-altitude environments with their low temperatures and low levels of oxygen (hypoxia) pose considerable challenges for small mammals. With their small body size and proportional large body surface they have to sustain high rates of aerobic metabolism to support thermogenesis and locomotion, which can be restricted with only limited levels of oxygen available. To generate insights into high-altitude adaptation I identified a large number of single nucleotide polymorphisms (SNPs). These data were first used to identify high levels of differentiation between study sites and a clear pattern of population structure, in line with a signal of isolation by distance. Using genome scan methods, I then identified signals of selection associated with differences in altitude in genes with functions related to oxygen transport into tissue and genes related to aerobic metabolic pathways. This indicates that hypoxia is an important selection pressure driving local adaptation at high altitude in M. arvalis. A number of these genes were linked with high-altitude adaptation in other species before, which lead to the suggestion that high-altitude populations of several species have evolved in a similar manner as a response to the unique conditions at high altitude The next study also involved the genetic basis of local adaptation, here I provided insights into climate-related adaptation in M. glareolus across its European distribution. Climate is an important environmental factor affecting the physiology of all organisms. In this study I identified a large number of SNPs in individuals from twelve M. glareolus populations distributed across Europe. I used these, to first establish that populations are highly differentiated and found a strong pattern of population structure with signal of isolation by distance. I then employed genome scan methods to identify candidate loci showing signals of selection associated with climate, with a particular emphasis on polygenic loci. A multivariate analysis was used to determine that temperature was the most important climate variable responsible for adaptive genetic variation among all variables tested. By using novel methods and genome annotation of related species I identified the function of genes of candidate loci. This showed that genes under selection have functions related to energy homeostasis and immune processes. Suggesting that M. glareolus populations have evolved in response to local temperature and specific local pathogenic selection pressures. The studies presented in this thesis provide evidence for the genetic basis of local adaptation in two vole species across different environmental gradients, suggesting that the identified genes are involved in local adaptation. This demonstrates that with the help of novel methods the study of wild populations, which often have little genomic resources available, can provide unique insights into evolutionary processes.},
  language  = {en}
}
@phdthesis{Fontana2020,
  author    = {Fontana, Federica},
  title     = {Antagonistic activities of Vegfr3/Flt4 and Notch1b fine-tune mechanosensitive signaling during zebrafish cardiac valvulogenesis},
  doi       = {10.25932/publishup-48751},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-487517},
  school      = {Universit{\"a}t Potsdam},
  pages     = {III, 110},
  year      = {2020},
  abstract  = {Cardiac valves are essential for the continuous and unidirectional flow of blood throughout the body. During embryonic development, their formation is strictly connected to the mechanical forces exerted by blood flow. The endocardium that lines the interior of the heart is a specialized endothelial tissue and is highly sensitive to fluid shear stress. Endocardial cells harbor a signal transduction machinery required for the translation of these forces into biochemical signaling, which strongly impacts cardiac morphogenesis and physiology. To date, we lack a solid understanding on the mechanisms by which endocardial cells sense the dynamic mechanical stimuli and how they trigger different cellular responses. In the zebrafish embryo, endocardial cells at the atrioventricular canal respond to blood flow by rearranging from a monolayer to a double-layer, composed of a luminal cell population subjected to blood flow and an abluminal one that is not exposed to it. These early morphological changes lead to the formation of an immature valve leaflet. While previous studies mainly focused on genes that are positively regulated by shear stress, the mechanisms regulating cell behaviors and fates in cells that lack the stimulus of blood flow are largely unknown. One key discovery of my work is that the flow-sensitive Notch receptor and Kr{\"u}ppel-like factor (Klf) 2, one of the best characterized flow-regulated transcriptional factors, are activated by shear stress but that they function in two parallel signal transduction pathways. Each of these two pathways is essential for the rearrangement of atrioventricular cells into an immature double-layered valve leaflets. A second key discovery of my study is the finding that both Notch and Klf2 signaling negatively regulate the expression of the angiogenesis receptor Vegfr3/Flt4, which becomes restricted to abluminal endocardial cells of the valve leaflet. Within these cells, Flt4 downregulates the expressions of the cell adhesion proteins Alcam and VE-cadherin. A loss of Flt4 causes abluminal endocardial cells to ectopically express Notch, which is normally restricted to luminal cells, and impairs valve morphology. My study suggests that abluminal endocardial cells that do not experience mechanical stimuli loose Notch expression and this triggers expression of Flt4. In turn, Flt4 negatively regulates Notch on the abluminal side of the valve leaflet. These antagonistic signaling activities and fine-tuned gene regulatory mechanisms ultimately shape cardiac valve leaflets by inducing unique differences in the fates of endocardial cells.},
  language  = {en}
}
@phdthesis{Friedrich2020,
  author    = {Friedrich, Alexander},
  title     = {Minimizers of generalized Willmore energies and applications in general relativity},
  doi       = {10.25932/publishup-48142},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-481423},
  school      = {Universit{\"a}t Potsdam},
  pages     = {100},
  year      = {2020},
  abstract  = {Das Willmore Funktional ist eine Funktion die jeder Fl{\"a}che in einer Riemannschen Mannigfaltigkeit, ihre totale mittlere Kr{\"u}mmung zuweist. Ein klassisches Problem der Differentialgeometrie ist es geschlossene (kompakt und ohne Rand) Fl{\"a}chen zu finden die das Willmore funktional minimieren, beziehungsweise die kritische Punkte des Willmore Funktionals sind. In dieser Doktorarbeit entwickeln wir ein Konzept von verallgemeinerten Willmore Funktionalen f{\"u}r Fl{\"a}chen in Riemannschen Mannigfaltigkeiten, wobei wir uns von physikalischen Modellen leiten lassen. Insbesondere ist hier die Hawking Energie der allgemeinen Relativit{\"a}tstheorie und die Biegungsenergie von d{\"u}nnen Membranen zu nennen. F{\"u}r dieses verallgemeinerten Willmore Funktionale beweisen wir die Existenz von Minimieren mit vorgeschriebenen Fl{\"a}cheninhalt, in einer geeigneten Klasse von verallgemeinerten Fl{\"a}chen. Insbesondere konstruieren wir Minimierer der oben erw{\"a}hnten Biegungsenergie mit vorgeschrieben Fl{\"a}cheninhalt und vorgeschriebenen, eingeschlossenem Volumen. Außerdem beweisen wir, dass kritische Punkte von verallgemeinerten Willmore Funktionalen mit vorgeschriebenen Fl{\"a}cheninhalt abseits endlich vieler Punkte glatt sind. Dabei st{\"u}tzen wir uns, wie auch im folgenden, auf die bestehende Theorie f{\"u}r das Willmore Funktional. An diese allgemeinen Resultate schließen wir eine detailliertere Analyse der Hawking Energie an. Im Kontext der allgemeinen Relativit{\"a}tstheorie beschreibt die Umgebungsmannigfaltigkeit den Raum zu einem Zeitpunkt. Daher sind wir an dem Wechselspiel zwischen der Hawking Energie und der umgebenden Mannigfaltigkeit interessiert. Wir charakterisieren Punkte in der umgebenden Mannigfaltigkeit f{\"u}r die es in jeder Umgebung eine kritische Fl{\"a}che mit vorgeschriebenem, kleinem Fl{\"a}cheninhalt gibt. Diese Punnkte werden als Konzentrationspunkte der Hawking Energie interpretiert. Außerdem berechnen wir eine Entwicklung der Hawking Energie auf kleinen, runden Sph{\"a}ren. Dadurch k{\"o}nnen wir eine Art Energiedichte der Hawking Energie identifizieren. Hierbei ist anzumerken, dass unsere Resultate im Kontrast zu Ergebnissen in der Literatur stehen. Dort wurde berechnet, dass die Entwicklung der Hawking Energie auf Sph{\"a}ren im Lichtkegel eines Punktes der umgebenden Mannigfaltigkeit in f{\"u}hrender Ordnung proportional zur der klassischen Energiedichte der allgemeinen Relativit{\"a}tstheorie ist. Zu diesem Zeitpunkt ist nicht klar wie diese Diskrepanz zu begr{\"u}nden ist. Ferner betrachten wir asymptotisch Schwarzschild Mannigfaltigkeiten. Sie sind ein Spezialfall von asymptotisch flachen Mannigfaltigkeiten, welche in der allgemeinen Relativit{\"a}tstheorie als Modelle f{\"u}r isolierte Systeme dienen. Die Schwarzschild Raumzeit selbst ist eine rotationssymmetrische Raumzeit die schwarzen Loch beschreibt. In diesen asymptotisch Schwarzschild Mannigfaltigkeiten konstruieren wir eine Bl{\"a}tterung des {\"a}ußeren Bereiches durch kritische Fl{\"a}chen der Hawking Energie mit vorgeschriebenen Fl{\"a}cheninhalt. Diese Bl{\"a}tterung kann in einem verallgemeinertem Sinne als Schwerpunkt des isolierten Systems betrachtet werden. Außerdem zeigen wir, dass die Hawking Energie entlang der Bl{\"a}tterung w{\"a}chst je gr{\"o}ßer die Fl{\"a}chen werden.},
  language  = {en}
}
@phdthesis{Friese2020,
  author    = {Friese, Andr{\´e}},
  title     = {Biogeochemistry of ferruginous sediments of Lake Towuti, Sulawesi, Indonesia},
  doi       = {10.25932/publishup-47535},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-475355},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxiv, 233},
  year      = {2020},
  abstract  = {Ferruginous conditions were a prominent feature of the oceans throughout the Precambrian Eons and thus throughout much of Earth's history. Organic matter mineralization and diagenesis within the ferruginous sediments that deposited from Earth's early oceans likely played a key role in global biogeochemical cycling. Knowledge of organic matter mineralization in ferruginous sediments, however, remains almost entirely conceptual, as modern analogue environments are extremely rare and largely unstudied, to date. Lake Towuti on the island of Sulawesi, Indonesia is such an analogue environment and the purpose of this PhD project was to investigate the rates and pathways of organic matter mineralization in its ferruginous sediments. Lake Towuti is the largest tectonic lake in Southeast Asia and is hosted in the mafic and ultramafic rocks of the East Sulawesi Ophiolite. It has a maximum water depth of 203 m and is weakly thermally stratified. A well-oygenated surface layer extends to 70 m depth, while waters below 130 m are persistently anoxic. Intensive weathering of the ultramafic catchment feeds the lake with large amounts of iron(oxy)hydroxides while the runoff contains only little sulfate, leading to sulfate-poor (< 20 µM) lake water and anoxic ferruginous conditions below 130 m. Such conditions are analogous to the ferruginous water columns that persisted throughout much of the Archean and Proterozoic eons. Short (< 35 cm) sediment cores were collected from different water depths corresponding to different bottom water redox conditions. Also, a drilling campaign of the International Continental Scientific Drilling Program (ICDP) retrieved a 114 m long sediment core dedicated for geomicrobiological investigations from a water depth of 153 m, well below the depth of oxygen penetration at the time of sampling. Samples collected from these sediment cores form the fundament of this thesis and were used to perform a suite of biogeochemical and microbiological analyses. Geomirobiological investigations depend on uncontaminated samples. However, exploration of subsurface environments relies on drilling, which requires the use of a drilling fluid. Drilling fluid infiltration during drilling can not be avoided. Thus, in order to trace contamination of the sediment core and to identify uncontaminated samples for further analyses a simple and inexpensive technique for assessing contamination during drilling operations was developed and applied during the ICDP drilling campaign. This approach uses an aqeous fluorescent pigment dispersion commonly used in the paint industry as a particulate tracer. It has the same physical properties as conventionally used particulate tracers. However, the price is nearly four orders of magnitude lower solving the main problem of particulate tracer approaches. The approach requires only a minimum of equipment and allows for a rapid contamination assessment potentially even directly on site, while the senstitivity is in the range of already established approaches. Contaminated samples in the drill core were identified and not included for further geomicrobiological investigations. Biogeochemical analyses of short sediment cores showed that Lake Towutis sediments are strongly depleted in electron acceptors commonly used in microbial organic matter mineralization (i.e. oxygen, nitrate, sulfate). Still, the sediments harbor high microbial cell densities, which are a function of redox conditions of Lake Towuti's bottom water. In shallow water depths bottom water oxygenation leads to a higher input of labile organic matter and electron acceptors like sulfate and iron, which promotes a higher microbial abundance. Microbial analyses showed that a versatile microbial community with a potential to perform metabolisms related to iron and sulfate reduction, fermentation as well as methanogenesis inhabits Lake Towuti's surface sediments. Biogeochemical investigations of the upper 12 m of the 114 m sediment core showed that Lake Towuti's sediment is extremely rich in iron with total concentrations up to 2500 µmol cm-3 (20 wt. \%), which makes it the natural sedimentary environment with the highest total iron concentrations studied to date. In the complete or near absence of oxygen, nitrate and sulfate, organic matter mineralization in ferruginous sediments would be expected to proceed anaerobically via the energetically most favorable terminal electron acceptors available - in this case ferric iron. Astonishingly, however, methanogenesis is the dominant (>85 \%) organic matter mineralization process in Lake Towuti's sediment. Reactive ferric iron known to be available for microbial iron reduction is highly abundant throughout the upper 12 m and thus remained stable for at least 60.000 years. The produced methane is not oxidized anaerobically and diffuses out of the sediment into the water column. The proclivity towards methanogenesis, in these very iron-rich modern sediments, implies that methanogenesis may have played a more important role in organic matter mineralization thoughout the Precambrian than previously thought and thus could have been a key contributor to Earth's early climate dynamics. Over the whole sequence of the 114 m long sediment core siderites were identified and characterized using high-resolution microscopic and spectroscopic imaging together with microchemical and geochemical analyses. The data show early diagenetic growth of siderite crystals as a response to sedimentary organic matter mineralization. Microchemical zoning was identified in all siderite crystals. Siderite thus likely forms during diagenesis through growth on primary existing phases and the mineralogical and chemical features of these siderites are a function of changes in redox conditions of the pore water and sediment over time. Identification of microchemical zoning in ancient siderites deposited in the Precambrian may thus also be used to infer siderite growth histories in ancient sedimentary rocks including sedimentary iron formations.},
  language  = {en}
}
@phdthesis{GaeteRojas2020,
  author    = {Gaete Rojas, Ayleen Barbara},
  title     = {Monitoring and modeling observations of plumbing systems at caldera-like topography},
  doi       = {10.25932/publishup-44613},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-446135},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 96},
  year      = {2020},
  abstract  = {In this dissertation, I describe the mechanisms involved in magmatic plumbing system establishment and evolution. Magmatic plumbing systems play a key role in determining volcanic activity style and recognizing its complexities can help in forecasting eruptions, especially within hazardous volcanic systems such as calderas. I explore the mechanisms of dike emplacement and intrusion geometry that shape magmatic plumbing systems beneath caldera-like topographies and how their characteristics relate to precursory activity of a volcanic eruption. For this purpose, I use scaled laboratory models to study the effect of stress field reorientation on a propagating dike induced by caldera topography. I construct these models by using solid gelatin to mimic the elastic properties of the earth's crust with a caldera on the surface. I inject water as the magma analog and track the evolution of the experiments through qualitative (geometry and stress evolution) and quantitative (displacement and strain computation) descriptions. The results show that a vertical dike deviates towards and outside of the caldera-like margin due to stress field reorientation beneath the caldera-like topography. The propagating intrusion forms a circumferential-eruptive dike when the caldera-like size is small, whereas a cone sheet develops beneath the large caldera-like topography. To corroborate the results obtained from the experimental models, this thesis also describes the results of a case study utilizing seismic monitoring data associated with the unrest period of the 2015 phreatic eruption of Lascar volcano. Lascar has a crater with a small-scale caldera-like topography and exhibited long-lasting anomalous evolution of the number of long-period (LP) events preceding the 2015 eruption. I apply seismic techniques to constrain the hypocentral locations of LP events and characterize their spatial distribution, obtaining an image of Lascar's plumbing system. I observe an agreement in shallow hypocentral locations obtained through four different seismic techniques; nevertheless, the cross-correlation technique provides the best results. These results depict a plumbing system with a narrow sub-vertical deep conduit and a shallow hydrothermal system, where most LP events are located. These two regions are connected through an intermediate region of path divergence, whose geometry and orientation likely is influenced by stress reorientation due to topographic effects of the caldera-like crater. Finally, in order to further enhance the interpretations of the previous case study, the seismic data was analyzed in tandem with a complementary multiparametric monitoring dataset. This complementary study confirms that the anomalous LP activity occurred as a sign of unrest in the preparatory phase of the phreatic eruption. In addition, I show how changes observed in other monitored parameters enabled to detect further signs of unrest in the shallow hydrothermal system. Overall, this study demonstrates that detecting complex geometric regions within plumbing systems beneath volcanoes is fundamental to produce an effective forecast of eruptions that from a first view seem to occur without any precursory activity. Furthermore, through the development of this research I show that combining methods that include both observations and models allows one to obtain a more precise interpretation of the volcanic processes.},
  language  = {en}
}
@phdthesis{Ghandour2020,
  author    = {Ghandour, Rabea},
  title     = {Identification of chloroplast translational feedback regulation and establishment of aptamer based mRNA purification to unravel involved regulatory factors},
  doi       = {10.25932/publishup-48289},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-482896},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIII, 173},
  year      = {2020},
  abstract  = {After endosymbiosis, chloroplasts lost most of their genome. Many former endosymbiotic genes are now nucleus-encoded and the products are re-imported post-translationally. Consequently, photosynthetic complexes are built of nucleus- and plastid-encoded subunits in a well-defined stoichiometry. In Chlamydomonas, the translation of chloroplast-encoded photosynthetic core subunits is feedback-regulated by the assembly state of the complexes they reside in. This process is called Control by Epistasy of Synthesis (CES) and enables the efficient production of photosynthetic core subunits in stoichiometric amounts. In chloroplasts of embryophytes, only Rubisco subunits have been shown to be feedback-regulated. That opens the question if there is additional CES regulation in embryophytes. I analyzed chloroplast gene expression in tobacco and Arabidopsis mutants with assembly defects for each photosynthetic complex to broadly answer this question. My results (i) confirmed CES within Rubisco and hint to potential translational feedback regulation in the synthesis of (ii) cytochrome b6f (Cyt b6f) and (iii) photosystem II (PSII) subunits. This work suggests a CES network in PSII that links psbD, psbA, psbB, psbE, and potentially psbH expression by a feedback mechanism that at least partially differs from that described in Chlamydomonas. Intriguingly, in the Cyt b6f complex, a positive feedback regulation that coordinates the synthesis of PetA and PetB was observed, which was not previously reported in Chlamydomonas. No evidence for CES interactions was found in the expression of NDH and ATP synthase subunits of embryophytes. Altogether, this work provides solid evidence for novel assembly-dependent feedback regulation mechanisms controlling the expression of photosynthetic genes in chloroplasts of embryophytes. In order to obtain a comprehensive inventory of the rbcL and psbA RNA-binding proteomes (including factors that regulate their expression, especially factors involved in CES), an aptamer based affinity purification method was adapted and refined for the specific purification these transcripts from tobacco chloroplasts. To this end, three different aptamers (MS2, Sephadex ,and streptavidin binding) were stably introduced into the 3' UTRs of psbA and rbcL by chloroplast transformation. RNA aptamer based purification and subsequent chip analysis (RAP Chip) demonstrated a strong enrichment of psbA and rbcL transcripts and currently, ongoing mass spectrometry analyses shall reveal potential regulatory factors. Furthermore, the suborganellar localization of MS2 tagged psbA and rbcL transcripts was analyzed by a combined affinity, immunology, and electron microscopy approach and demonstrated the potential of aptamer tags for the examination of the spatial distribution of chloroplast transcripts.},
  language  = {en}
}
@phdthesis{Harmanli2020,
  author    = {Harmanli, İpek},
  title     = {Towards catalytic activation of nitrogen in ionic liquid/nanoporous carbon interfaces for electrochemical ammonia synthesis},
  doi       = {10.25932/publishup-48359},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-483591},
  school      = {Universit{\"a}t Potsdam},
  pages     = {v, 126},
  year      = {2020},
  abstract  = {Ammonia is a chemical of fundamental importance for nature`s vital nitrogen cycle. It is crucial for the growth of living organisms as well as food and energy source. Traditionally, industrial ammonia production is predominated by Haber- Bosch process (HBP) which is based on direct conversion of N2 and H2 gas under high temperature and high pressure (~500oC, 150-300 bar). However, it is not the favorite route because of its thermodynamic and kinetic limitations, and the need for the energy intense production of hydrogen gas by reforming processes. All these disfavors of HBP open a target to search for an alternative technique to perform efficient ammonia synthesis via electrochemical catalytic processes, in particular via water electrolysis, using water as the hydrogen source to save the process from gas reforming. In this study, the investigation of the interface effects between imidazolium-based ionic liquids and the surface of porous carbon materials with a special interest in the nitrogen absorption capability. As the further step, the possibility to establish this interface as the catalytically active area for the electrochemical N2 reduction to NH3 has been evaluated. This particular combination has been chosen because the porous carbon materials and ionic liquids (IL) have a significant importance in many scientific fields including catalysis and electrocatalysis due to their special structural and physicochemical properties. Primarily, the effects of the confinement of ionic liquid (EmimOAc, 1-Ethyl-3-methylimidazolium acetate) into carbon pores have been investigated. The salt-templated porous carbons, which have different porosity (microporous and mesoporous) and nitrogen species, were used as model structures for the comparison of the IL confinement at different loadings. The nitrogen uptake of EmimOAc can be increased by about 10 times by the confinement in the pores of carbon materials compared to the bulk form. In addition, the most improved nitrogen absorption was observed by IL confinement in micropores and in nitrogen-doped carbon materials as a consequence of the maximized structural changes of IL. Furthermore, the possible use of such interfaces between EmimOAc and porous carbon for the catalytic activation of dinitrogen during the kinetically challenging NRR due to the limited gas absorption in the electrolyte, was examined. An electrocatalytic NRR system based on the conversion of water and nitrogen gas to ammonia at ambient operation conditions (1 bar, 25 °C) was performed in a setup under an applied electric potential with a single chamber electrochemical cell, which consists of the combination of EmimOAc electrolyte with the porous carbon-working electrode and without a traditional electrocatalyst. Under a potential of -3 V vs. SCE for 45 minutes, a NH3 production rate of 498.37 μg h-1 cm-2 and FE of 12.14\% were achieved. The experimental observations show that an electric double-layer, which serves the catalytically active area, occurs between a microporous carbon material and ions of the EmimOAc electrolyte in the presence of sufficiently high provided electric potential. Comparing with the typical NRR systems which have been reported in the literature, the presented electrochemical ammonia synthesis approach provides a significantly higher ammonia production rate with a chance to avoid the possible kinetic limitations of NRR. In terms of operating conditions, ammonia production rate and the faradic efficiency without the need for any synthetic electrocatalyst can be resulted of electrocatalytic activation of nitrogen in the double-layer formed between carbon and IL ions.},
  language  = {en}
}
@phdthesis{Harmouch2020,
  author    = {Harmouch, Hazar},
  title     = {Single-column data profiling},
  doi       = {10.25932/publishup-47455},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-474554},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 115},
  year      = {2020},
  abstract  = {The research area of data profiling consists of a large set of methods and processes to examine a given dataset and determine metadata about it. Typically, different data profiling tasks address different kinds of metadata, comprising either various statistics about individual columns (Single-column Analysis) or relationships among them (Dependency Discovery). Among the basic statistics about a column are data type, header, the number of unique values (the column's cardinality), maximum and minimum values, the number of null values, and the value distribution. Dependencies involve, for instance, functional dependencies (FDs), inclusion dependencies (INDs), and their approximate versions. Data profiling has a wide range of conventional use cases, namely data exploration, cleansing, and integration. The produced metadata is also useful for database management and schema reverse engineering. Data profiling has also more novel use cases, such as big data analytics. The generated metadata describes the structure of the data at hand, how to import it, what it is about, and how much of it there is. Thus, data profiling can be considered as an important preparatory task for many data analysis and mining scenarios to assess which data might be useful and to reveal and understand a new dataset's characteristics. In this thesis, the main focus is on the single-column analysis class of data profiling tasks. We study the impact and the extraction of three of the most important metadata about a column, namely the cardinality, the header, and the number of null values. First, we present a detailed experimental study of twelve cardinality estimation algorithms. We classify the algorithms and analyze their efficiency, scaling far beyond the original experiments and testing theoretical guarantees. Our results highlight their trade-offs and point out the possibility to create a parallel or a distributed version of these algorithms to cope with the growing size of modern datasets. Then, we present a fully automated, multi-phase system to discover human-understandable, representative, and consistent headers for a target table in cases where headers are missing, meaningless, or unrepresentative for the column values. Our evaluation on Wikipedia tables shows that 60\% of the automatically discovered schemata are exact and complete. Considering more schema candidates, top-5 for example, increases this percentage to 72\%. Finally, we formally and experimentally show the ghost and fake FDs phenomenon caused by FD discovery over datasets with missing values. We propose two efficient scores, probabilistic and likelihood-based, for estimating the genuineness of a discovered FD. Our extensive set of experiments on real-world and semi-synthetic datasets show the effectiveness and efficiency of these scores.},
  language  = {en}
}
@phdthesis{Haupt2020,
  author    = {Haupt, Maria},
  title     = {The Magellanic Clouds in VHE gamma rays as seen by H.E.S.S.},
  doi       = {10.25932/publishup-47460},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-474601},
  school      = {Universit{\"a}t Potsdam},
  pages     = {iv, 182},
  year      = {2020},
  abstract  = {Das Gebiet der Gammastrahlungsastronomie hat ein neues Fenster in das nicht-thermische Universum geöffnet, welches erlaubt, die Beschleunigungsorte der kosmischen Strahlung und ihrer Rolle in evolutionären Prozessen in Galaxien zu untersuchen. Der Nachweis von fast einhundert sehr hochenergetischen Gammastrahlungsquellen in unserer Milchstraße zeigt, dass Teilchenbeschleunigung bis in den zweistelligen TeV-Energiebereich ein häufiges Phänomen ist. Dar{\"u}ber hinaus hat der Nachweis von sehr hochenergetischer Gammastrahlung von anderen Galaxien bestätigt, dass die kosmische Strahlung nicht ausschließlich in der Milchstraße beschleunigt wird. Die rasante Entwicklung der Gammastrahlungsastronomie in den letzten zwei Jahrzehnten f{\"u}hrte zu einem Übergang von der Detektion und Untersuchung einzelner Quellen hin zu Quellpopulationsstudien. Um die Frage zu beantworten, ob die Quellpopulationen hochenergetischer Gammastrahlung in der Milchstraße einzigartig sind, sind Beobachtungen von anderen Galaxien erforderlich, f{\"u}r die es möglich ist, trotz ihrer Entfernung, einzelne Quellen aufzulösen. Die Magellanschen Wolken, zwei Satellitengalaxien der Milchstraße, sind solche Galaxien, welche im letzten Jahrzehnt durch das H.E.S.S.-Experiment intensiv beobachtet wurden. In dieser Arbeit werden die Daten von insgesamt 450 Stunden H.E.S.S.-Beobachtungen der Großen Magellanschen Wolke und der Kleinen Magellanschen Wolke vorgestellt. Während der Analyse der Datensätze wird besonderer Wert auf die Evaluierung der systematischen Unsicherheiten des Experiments gelegt, um eine unverfälschte Flussabschätzung der potentiellen hochenergetischen Gammastrahlungsquellen der Magellanschen Wolken zu gewährleisten. Die detaillierte Analyse der Beobachtungen f{\"u}hrte zur Detektion hochenergetischer Gammastrahlung des Binärsystems LMC P3 in der Großen Magellanschen Wolke und erhöht somit die Anzahl der detektierten Gammastrahlungsquellen in dieser Galaxie auf vier. Dieses neuentdeckte Binärsystem ist das bisher leuchtstärkste in der Quellklasse der Gammastrahlungsbinärsysteme. F{\"u}r keine andere Quelle in den Magellanschen Wolken wird hochenergetische Gammastrahlung nachgewiesen und es werden Obergrenzen auf den integralen Fluss ermittelt. Diese Flussobergrenzen werden verwendet, um Populationsstudien auf der Grundlage bekannter hochenergetischer Quellklassen sowie bestehender Quellkataloge anderer Wellenlängen durchzuf{\"u}hren. Ein systematischer Vergleich zwischen den Quellpopulationen der Magellanschen Wolken und der Milchstraße ergab, dass keine andere Quelle der Magellanschen Wolken so leuchtstark ist wie die leuchtstärkste hochenergetische Gammastrahlungsquelle in der LMC: der Pulsarwindnebel N157B. Des Weiteren ist ein Drittel der untersuchten Quellpopulation der Magellanschen Wolken weniger leuchtstark als die vier bekannten Gammastrahlungsquellen in der Großen Magellanschen Wolke. F{\"u}r einige wenige Quellen kann gezeigt werden, dass sie weniger leuchtstark sind als die leuchtstärksten Objekte in der Milchstraße, deren Leuchtkraft um mehr als eine Größenordnung schwächer ist als die der detektierten Quellen in der Großen Magellanschen Wolke. Basierend auf den Flussobergrenzen werden Unterschiede in den Quellpopulationen der Magellanschen Wolken und der Milchstraße sowie die Bedeutung der Quellumgebungen diskutiert.},
  language  = {en}
}
@phdthesis{Helm2020,
  author    = {Helm, Norman},
  title     = {Optimierung der Leistungsdiagnostik und Entwicklung von effektiven Trainingsprogrammen in der Zweikampfsportart Judo unter Verwendung des Mess- und Informationssystems JERGo f{\"u}r judospezifische Anrissbewegungen},
  doi       = {10.25932/publishup-47176},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471765},
  school      = {Universit{\"a}t Potsdam},
  pages     = {IX,145},
  year      = {2020},
  abstract  = {Eine sportartspezifische Anforderungsanalyse ist die Grundlage f{\"u}r die Leistungsdiagnostik und eine wichtige Voraussetzung f{\"u}r die Trainingssteuerung im Spitzensport. Im Rahmen der Leistungsdiagnostik in der Zweikampfsportart Judo besitzen judospezifische Anrissleistungen bei Anrissbewegungen ein hohes Potenzial, um Defizite im Kraft-Weg-Verlauf bzw. in den kinetischen Parametern (z. B. mechanische Arbeit, dynamische Maximalkraft) zu identifizieren und ableitend daraus entsprechende trainingsmethodische Anpassungen zur Verbesserung vorzunehmen. Die Rumpfstabilit{\"a}t und die Rumpfkraft stellen wichtige Leistungsvoraussetzungen f{\"u}r sportliche Bewegungen dar, um den optimalen Transfer von Kr{\"a}ften und Drehmomenten von den unteren Extremit{\"a}ten {\"u}ber den stabilen Rumpf hin zu den oberen Extremit{\"a}ten zu erm{\"o}glichen. Im Trainingsprozess der Judoka erf{\"a}hrt das spezifische Krafttraining immer mehr Aufmerksamkeit, um die sportartrelevanten Muskelgruppen zu entwickeln und somit die finale Effektivit{\"a}t einer Wurftechnik zu verbessern. Die wesentliche Zielstellung dieser Arbeit bestand darin, die Leistungsdiagnostik im Judo zu optimieren und effektive Trainingsprogramme zur Verbesserung von judospezifischen Anrissbewegungen zu entwickeln. Im Einzelnen wurde daf{\"u}r eine systematische Anforderungsanalyse f{\"u}r die Sportart Judo erarbeitet. Basierend auf dieser Analyse wurden die Validit{\"a}t und die Reliabilit{\"a}t von kinetischen Parametern w{\"a}hrend Anrissbewegungen mit einem judospezifischen Ergometer-System (JERGo) untersucht. Zudem wurden die Zusammenh{\"a}nge zwischen der Rumpfkraft und kinetischen Parametern bei judospezifischen Anrissbewegungen analysiert. Schließlich wurde die Wirksamkeit eines spezifischen Anrisstrainings am JERGo-System gegen{\"u}ber einem Anrisstraining mit Partner auf kinetische Parameter und Muskelaktivit{\"a}t {\"u}berpr{\"u}ft. Die sportartspezifische Anforderungsanalyse wurde unter Ber{\"u}cksichtigung der metabolischen und muskul{\"a}ren Anforderungen sowie sportartspezifischen Verletzungsrisiken erarbeitet. An den zwei Querstudien bzw. einer L{\"a}ngsschnittstudie nahmen gesunde m{\"a}nnliche Judoka mit unterschiedlichem Expertiseniveau teil. Die kinetischen Parameter bei judospezifischen Anrissbewegungen wurden mit dem JERGo-System in allen Experimentalstudien erfasst. Die Rumpfkraft wurde mit einem isokinetischen Dynamometer gemessen, um Assoziationen zwischen der Rumpfkraft und judospezifischen Anrissleistungen zu bestimmen. Zudem wurde die Aktivit{\"a}t ausgew{\"a}hlter Rumpf-/Schultermuskeln bei der Anrissbewegung im Standf{\"u}r die Validierung des JERGo-Systems und f{\"u}r die {\"U}berpr{\"u}fung der Effekte eines Anrisstrainings erfasst. Die Ermittlung von sportmotorischen Leistungen erfolgte durch die {\"U}bungen Liegend-Anreißen und Klimmziehen, um die Wirkungen eines judospezifischen Anrisstrainings auf sportartunspezifische Kraftleistungen zu untersuchen. Unter Ber{\"u}cksichtigung der muskul{\"a}ren Anforderungen im Judo wird die Ausf{\"u}hrung einer explosiven Anrissbewegung bzw. Wurftechnik durch die koordinierte Aktivit{\"a}t vieler Muskelgruppen und vor allem durch die unteren Extremit{\"a}ten sowie den Rumpf realisiert. Aus trainingswissenschaftlicher Sicht ist das JERGo-System ein valides und reliables Messinstrument f{\"u}r die Diagnostik von kinetischen Parametern w{\"a}hrend judospezifischer Anrissbewegungen. Die Rumpfkraft, insbesondere bei der Rumpfrotation, ist mit kinetischen Parametern bei judospezifischen Anrissbewegungen assoziiert. Ein Anrisstraining am JERGo-System zeigt in den kinetischen Parametern und Muskelaktivierungen vor allem bei der Anrissbewegung im Stand signifikant gr{\"o}ßere Zuwachsraten im Vergleich zu einem Anrisstraining mit Partner. Die Ergebnisse dieser Arbeit zeigen, dass die Verbesserung der muskul{\"a}ren Leistungsf{\"a}higkeit (z. B. Explosivkraft) in den unteren Extremit{\"a}ten und der Rumpfmuskulatur eine wichtige Basis f{\"u}r judospezifische Anrissleistungen bei Anrissbewegungen und Wurftechniken darstellt. Zudem empfiehlt es sich, dass JERGo-System zur Diagnostik von kinetischen Parametern bei judospezifischen Anrissbewegungen in die judospezifische Testbatterie einzubinden. Weiterhin kann davon ausgegangen werden, dass durch rumpfextensions- und vor allem durch rumpfrotationskr{\"a}ftigende {\"U}bungen unter maximal schellkr{\"a}ftigender Muskelaktivierung Einfluss auf kinetische Parameter bei judospezifischen Anrissbewegungen genommen wird. Letztendlich empfiehlt es sich, ein Antrisstraining am JERGo-System in den judospezifischen Trainingsprozess zu integrieren.},
  language  = {de}
}
@phdthesis{HernandezAnguizola2020,
  author    = {Hernandez Anguizola, Eloy Luis},
  title     = {Numerical simulations in multimode fibres for astronomical spectroscopy},
  doi       = {10.25932/publishup-47236},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-472363},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvi, 114},
  year      = {2020},
  abstract  = {The goal of this thesis was to thoroughly investigate the behavior of multimode fibres to aid the development of modern and forthcoming fibre-fed spectrograph systems. Based on the Eigenmode Expansion Method, a field propagation model was created that can emulate effects in fibres relevant for astronomical spectroscopy, such as modal noise, scrambling, and focal ratio degradation. These effects are of major concern for any fibre-coupled spectrograph used in astronomical research. Changes in the focal ratio, modal distribution of light or non-perfect scrambling limit the accuracy of measurements, e.g. the flux determination of the astronomical object, the sky-background subtraction and detection limit for faint galaxies, or the spectral line position accuracy used for the detection of extra-solar planets. Usually, fibres used for astronomical instrumentation are characterized empirically through tests. The results of this work allow to predict the fibre behaviour under various conditions using sophisticated software tools to simulate the waveguide behaviour and mode transport of fibres. The simulation environment works with two software interfaces. The first is the mode solver module FemSIM from Rsoft. It is used to calculate all the propagation modes and effective refractive indexes of a given system. The second interface consists of Python scripts which enable the simulation of the near- and far-field outputs of a given fibre. The characteristics of the input field can be manipulated to emulate real conditions. Focus variations, spatial translation, angular fluctuations, and disturbances through the mode coupling factor can also be simulated. To date, complete coherent propagation or complete incoherent propagation can be simulated. Partial coherence was not addressed in this work. Another limitation of the simulations is that they work exclusively for the monochromatic case and that the loss coefficient of the fibres is not considered. Nevertheless, the simulations were able to match the results of realistic measurements. To test the validity of the simulations, real fibre measurements were used for comparison. Two fibres with different cross-sections were characterized. The first fibre had a circular cross-section, and the second one had an octagonal cross-section. The utilized test-bench was originally developed for the prototype fibres of the 4MOST fibre feed characterization. It allowed for parallel laser beam measurements, light cone measurements, and scrambling measurements. Through the appropriate configuration, the acquisition of the near- and/or far-field was feasible. By means of modal noise analysis, it was possible to compare the near-field speckle patterns of simulations and measurements as a function of the input angle. The spatial frequencies that originate from the modal interference could be analyzed by using the power spectral density analysis. Measurements and simulations yielded similar results. Measurements with induced modal scrambling were compared to simulations using incoherent propagation and once again similar results were achieved. Through both measurements and simulations, the enlargement of the near-field distribution could be observed and analyzed. The simulations made it possible to explain incoherent intensity fluctuations that appear in real measurements due to the field distribution of the active propagation modes. By using the Voigt analysis in the far-field distribution, it was possible to separate the modal diffusion component in order to compare it with the simulations. Through an appropriate assessment, the modal diffusion component as a function of the input angle could be translated into angular divergence. The simulations gave the minimal angular divergence of the system. Through the mean of the difference between simulations and measurements, a figure of merit is given which can be used to characterize the angular divergence of real fibres using the simulations. Furthermore, it was possible to simulate light cone measurements. Due to the overall consistent results, it can be stated that the simulations represent a good tool to assist the fibre characterization process for fibre-fed spectrograph systems. This work was possible through the BMBF Grant 05A14BA1 which was part of the phase A study of the fibre system for MOSAIC, a multi-object spectrograph for the Extremely Large Telescope (ELT-MOS).},
  language  = {en}
}
@phdthesis{HerreraBorquez2020,
  author    = {Herrera Borquez, Kenya},
  title     = {La cabrona aqu{\´i} soy yo},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-460-9},
  issn      = {2629-2548},
  doi       = {10.25932/publishup-42727},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427274},
  school      = {Universit{\"a}t Potsdam},
  year      = {2020},
  abstract  = {La {\´u}ltima d{\´e}cada ha visto un inter{\´e}s creciente en el fen{\´o}meno del narcotr{\´a}fico en M{\´e}xico a nivel global. Las diversas expresiones de violencia extrema que acompa{\~n}an al negocio ilegal de drogas se narran en artefactos medi{\´a}ticos que provocan fascinaci{\´o}n e intriga. As{\´i}, la literatura y el cine, la m{\´u}sica y la televisi{\´o}n presentan im{\´a}genes e historias sobre el narcotr{\´a}fico que alimentan el imaginario colectivo. En este contexto, a nivel global hay representaciones medi{\´a}ticas de la mujer mexicana narcotraficante que reproducen estereotipos femeninos donde la mujer se cosifica, exagerando los atributos sexuales del cuerpo de las mujeres. Esta representaci{\´o}n cultural hace de la mujer un objeto de deseo, cuya belleza sirve como una marca de prestigio y ostentaci{\´o}n para el hombre narcotraficante. La cultura del narcotr{\´a}fico impone a las mujeres un ideal est{\´e}tico particular distintivo, que las mujeres reproducen meticulosamente para emular esta representaci{\´o}n. Aunado a la belleza f{\´i}sica, la mujer es retratada violenta y sin escr{\´u}pulos, usa su belleza y poder de seducci{\´o}n para acumular dinero y poder a costa de los hombres que conquista. Para los que no pertenecen al mundo del narcotr{\´a}fico, este tipo de mujer, hipersexualizada, inspira juicios negativos, discriminaci{\´o}n, desconfianza y temor. La intenci{\´o}n de la pregunta y objetivos de investigaci{\´o}n de este trabajo fue rebasar estas representaciones para observar las complejidades de las experiencias de vida de estas mujeres. El prop{\´o}sito de esta tesis de doctorado fue explorar c{\´o}mo cambian las vidas de las mujeres mexicanas cuando se involucran en la narcocultura, en la frontera M{\´e}xico-Estados Unidos. En espec{\´i}fico, la investigaci{\´o}n analiz{\´o} las transformaciones en la corporalidad y en las subjetividades de estas mujeres, y c{\´o}mo estas transformaciones influ{\´i}an en el lugar que ocupan en el espacio social y cultural que configura el narcotr{\´a}fico. Adem{\´a}s, se analiz{\´o} qu{\´e} m{\´a}rgenes de negociaci{\´o}n tienen las mujeres en la narcocultura, para poder actuar y definirse a s{\´i} mismas. Las preguntas que guiaron el trabajo indagaban sobre c{\´o}mo las mujeres cambiaban su cuerpo para encarnar el ideal est{\´e}tico y qu{\´e} significados se atribu{\´i}an a estos cambios. Fue importante analizar qu{\´e} din{\´a}micas de poder se pon{\´i}an en juego a partir de estos cuerpos femeninos, en las relaciones con los hombres y con otras mujeres. Tambi{\´e}n, otro objetivo fue qu{\´e} procesos de subjetivaci{\´o}n operaban en las mujeres que participan en la narcocultura, y qu{\´e} m{\´a}rgenes de negociaci{\´o}n ten{\´i}an para actuar y definirse a s{\´i} mismas. Esta es una investigaci{\´o}n inscrita dentro de los estudios culturales y con una perspectiva feminista interseccional. La investigaci{\´o}n se realiz{\´o} en la frontera mexicana con Estados Unidos, en el noroeste, espec{\´i}ficamente en las ciudades de Mexicali, Tijuana y San Diego, California. La frontera, en esta tesis, se observa como un espacio con m{\´u}ltiples contextos de interpretaci{\´o}n, polis{\´e}mico y heterog{\´e}neo. Estas cualidades hacen que los fen{\´o}menos culturales que ocurren en {\´e}l sean diversos y contradictorios. Para entender los fen{\´o}menos culturales que emergen de la frontera norte de M{\´e}xico, fue {\´u}til el concepto de transfrontera de Jos{\´e} Valenzuela Arce (2014). La propuesta de este acad{\´e}mico es que las transfronteras son "espacios que se niegan a una sola de las condiciones o los lados que la integran" (p. 9). As{\´i}, el concepto habla de los procesos de conectividad y simultaneidad que la globalizaci{\´o}n genera y que redefinen a los Estados-territorio. Al mismo tiempo, habla tambi{\´e}n de los l{\´i}mites que estos mismos Estados utilizan para sostener narrativas nacionales que son "referentes organizadores de adscripciones identitarias y culturales" (p. 18) que crean diferencias y desigualdades. Si esto es as{\´i}, una frontera no se explica completamente desde la demarcaci{\´o}n territorial o desde la diferenciaci{\´o}n jer{\´a}rquica que incluye a algunos y excluye a otros, pero tampoco puede entenderse si nos concentramos solamente en los procesos de hibridaci{\´o}n cultural que ocurren en esos espacios. Por eso, para Valenzuela las fronteras son entre espacios y entre tiempos. Este concepto ayuda a entender c{\´o}mo se intersecta lo global y local en los sistemas semi{\´o}ticos que componen el universo cultural del narcotr{\´a}fico mexicano, al mismo tiempo que explica c{\´o}mo se estructuran mecanismos de exclusi{\´o}n y jerarqu{\´i}as a partir del g{\´e}nero, la posici{\´o}n social y otras marcas de diferenciaci{\´o}n social. En {\´u}ltima instancia, ayuda a localizar estos procesos culturales, materializados en el cuerpo de las mujeres. El concepto de narcocultura tambi{\´e}n fue una herramienta heur{\´i}stica {\´u}til. La cultura aqu{\´i} se entiende como un proceso de producci{\´o}n y reproducci{\´o}n de modelos simb{\´o}licos, materializados en artefactos o representaciones y, adem{\´a}s, interiorizados en l{\´o}gicas de vida, sistemas de valores y creencias, que circulan a trav{\´e}s de las pr{\´a}cticas individuales y colectivas de mujeres y hombres, en contextos hist{\´o}ricos y espaciales espec{\´i}ficos. La narcocultura ser{\´i}a entonces el sistema semi{\´o}tico producido en torno al negocio transnacional de tr{\´a}fico ilegal de drogas, tal como se vive en la frontera norte de M{\´e}xico. La narcocultura, tal como se define en este trabajo es un sistema semi{\´o}tico con l{\´i}mites difusos. As{\´i}, las distinciones entre el mundo ilegal del narcotr{\´a}fico y el mundo de la legalidad externo a este negocio, en el mejor de los casos son borrosas, en el peor, ficticias. La narcocultura trasciende l{\´i}mites territoriales, es un fen{\´o}meno cultural transnacional. Fue necesario delinear las caracter{\´i}sticas de los estudios culturales latinoamericanos y los Kulturwissenschaften en Alemania, para distinguir las genealog{\´i}as de estas dos diferentes perspectivas, entender sus diferencias, pero, sobre todo, encontrar los puntos en com{\´u}n entre ellas. La coincidencia central fue el car{\´a}cter transdisciplinario de estas dos tradiciones acad{\´e}micas. Los estudios culturales entonces se entienden como un espacio de articulaci{\´o}n entre disciplinas (Castro G{\´o}mez, 2002), que no tiene como objetivo la unificaci{\´o}n sino la pluralizaci{\´o}n de significados, actitudes y modos de percepci{\´o}n (Bachmann-Medick, 2016). La transdisciplina permite trazar las complejidades de los fen{\´o}menos culturales, creando puentes entre diferentes formas de conocimiento y pr{\´a}cticas de investigaci{\´o}n. El feminismo interseccional es una perspectiva central en el trabajo de investigaci{\´o}n. Una contribuci{\´o}n del feminismo a los estudios culturales que influye en esta investigaci{\´o}n es cuestionar "Hombre" y "Mujer" como esencias naturales dadas e inmutables, desde la premisa que "los signos "hombre" y "mujer" son construcciones discursivas que el lenguaje de la cultura proyecta e inscribe en el escenario de los cuerpos, disfrazando sus montajes de signos tras la falsa apariencia de que lo masculino y lo femenino son verdades naturales, ahist{\´o}ricas" (Richard, 2009, p. 77). Los estudios culturales feministas suponen que estos signos se construyen en un sistema de representaciones que articulan subjetividades en mundos culturales concretos. Su objetivo entonces es develar en las pr{\´a}cticas significantes, los elementos ideol{\´o}gicos que configuran los signos y los conflictos que se suscitan a trav{\´e}s del uso e interpretaci{\´o}n de {\´e}stos. Estos signos adquieren m{\´u}ltiples significados y lecturas de acuerdo con especificidades que se distinguen en la diferencia. La interseccionalidad, dentro del feminismo es un discurso te{\´o}rico y metodol{\´o}gico que aboga por reconocer que el signo "mujer" no es una categor{\´i}a absoluta, y por lo tanto no puede explicar por s{\´i} misma las variadas experiencias vitales de las mujeres. Las diferencias se vuelven legibles cuando se ponen en juego con otras categor{\´i}as sociales como la posici{\´o}n social, la raza, la edad y la discapacidad. Las diferencias sociales est{\´a}n fincadas en diferentes discursos que naturalizan los diferentes atributos de estas categor{\´i}as sociales cuando, para esta perspectiva, son socialmente construidos y cambiantes. El objetivo de una perspectiva interseccional es identificar c{\´o}mo interact{\´u}an diferentes categor{\´i}as sociales en instituciones, pr{\´a}cticas y subjetividades, para entender c{\´o}mo se materializan las desigualdades a trav{\´e}s del tiempo. Los conceptos te{\´o}ricos que gu{\´i}an esta tesis son cuerpo y subjetividad. Para esta tesis, el cuerpo se entiende como un sitio de articulaci{\´o}n, donde se materializan c{\´o}digos culturales y el orden social. El cuerpo puede entenderse como una frontera din{\´a}mica y mutable, donde convergen lo f{\´i}sico, lo simb{\´o}lico y lo social. Sujeto y cuerpo son mutuamente constitutivos; el cuerpo es el medio a trav{\´e}s del cual el sujeto vive experiencias en el mundo social, y son esas experiencias las que llevan al sujeto a encarnar las diferencias sociales, materializadas en g{\´e}nero, sexo, clase social y raza. A pesar de esta relaci{\´o}n indisociable, para facilitar el an{\´a}lisis, una parte se concentra en el cuerpo y otra en la subjetividad. As{\´i}, para entender la dimensi{\´o}n corporal se puso en tensi{\´o}n la representaci{\´o}n con la experiencia vivida, a trav{\´e}s del an{\´a}lisis audiovisual y la observaci{\´o}n etnogr{\´a}fica le{\´i}da en conjunto. En el caso de la subjetividad, se puso en tensi{\´o}n la vida en la narrativa de ficci{\´o}n con las narraciones de vida en entrevistas, para tambi{\´e}n encontrar los puentes entre las representaciones y la experiencia vital. Esta investigaci{\´o}n fue un estudio cualitativo y transdisciplinario. Se utilizaron diversos recursos metodol{\´o}gicos para construir el an{\´a}lisis. Se realiz{\´o} observaci{\´o}n etnogr{\´a}fica en diversos bares y clubs a ambos lados de la frontera, que son frecuentados por personas que se adscriben al mundo de la narcocultura o bien, que trabajan dentro de las redes del narcotr{\´a}fico. En las incursiones a estos sitios, se observ{\´o} el f{\´i}sico de las mujeres: su manera de vestir, su arreglo personal, sus formas corporales. Se observ{\´o} la conducta: las gestualidades y las interacciones con otros sujetos en el espacio. Adem{\´a}s, se observ{\´o} el espacio, para ver c{\´o}mo se establec{\´i}an reglas, l{\´i}mites y jerarquizaciones en la disposici{\´o}n f{\´i}sica de los lugares visitados. Se analizaron tres videos de narcocorridos a trav{\´e}s de la video hermen{\´e}utica, para determinar c{\´o}mo se representan las mujeres en estos artefactos culturales, usando los mismos criterios f{\´i}sicos y conductuales que mencion{\´e} anteriormente. El an{\´a}lisis de los videos de la mano del trabajo etnogr{\´a}fico ayud{\´o} a profundizar en los significados atribuidos a la corporalidad femenina, y tambi{\´e}n a los impactos que estos significados tienen en las vivencias y relaciones de estas mujeres. Se realizaron 5 entrevistas semi estructuradas con mujeres que se identificaban con la narcocultura. Algunas s{\´o}lo simpatizan con el estilo de vida, otras estuvieron involucradas de alguna manera en el negocio ilegal de drogas. En las entrevistas se exploraron narraciones sobre sus vidas donde se revelaban discursos sobre qu{\´e} es lo femenino, qu{\´e} significa ser mujer y c{\´o}mo se vive el ser mujer en el mundo del narcotr{\´a}fico. Adicionalmente, utilic{\´e} las narraciones de dos textos literarios de la narrativa sobre narcotr{\´a}fico del norte de M{\´e}xico. En estos dos textos, los personajes principales son mujeres. Analic{\´e} c{\´o}mo se construye al sujeto femenino en la narraci{\´o}n y qu{\´e} discursos se transparentan en el texto sobre la feminidad y ser una mujer en el mundo del narco. Aqu{\´i} tambi{\´e}n se puso en tensi{\´o}n la representaci{\´o}n y la experiencia de vida, buscando en el an{\´a}lisis de la narraci{\´o}n literaria y las experiencias narradas por las mujeres, discursos comunes que explicaran los procesos de subjetivaci{\´o}n femenina dentro de la narcocultura mexicana. La primera parte del an{\´a}lisis articul{\´o} la observaci{\´o}n etnogr{\´a}fica con el material audiovisual para entender las exigencias est{\´e}ticas que la narcocultura demanda a las mujeres y las maneras en que ellas transforman su cuerpo para complacer esta demanda. La narcocultura impone a las mujeres un ideal est{\´e}tico que se convierte en un medio de acceso a un tipo de poder. Este ideal exige un tipo particular de fisonom{\´i}a y de apariencia personal, que las mujeres intentan reproducir a trav{\´e}s de intervenciones en el cuerpo, con el maquillaje y el peinado y/o la cirug{\´i}a est{\´e}tica. Adem{\´a}s, demanda cierto estilo de moda, en ropa y accesorios, de marcas de lujo de consumo global. Entre m{\´a}s fielmente se reproduzca este ideal, las mujeres est{\´a}n en posibilidad de acceder a beneficios econ{\´o}micos y sociales que les dan m{\´a}rgenes de acci{\´o}n dentro de este entorno social. El cuerpo de las mujeres se convierte en el recurso primario para la movilidad social y la agencia dentro de este mundo. El cuerpo es el signo principal para determinar el lugar de las mujeres dentro de los sistemas de jerarquizaci{\´o}n, de inclusi{\´o}n y exclusi{\´o}n en los espacios f{\´i}sicos y sociales que fabrica el narcotr{\´a}fico. Estos mecanismos de diferencia reproducen las desigualdades sociales, de g{\´e}nero, edad, posici{\´o}n social y raza que se observan en otros {\´a}mbitos de la sociedad mexicana. La observaci{\´o}n etnogr{\´a}fica y el an{\´a}lisis audiovisual revelan que las posibilidades para performar la feminidad est{\´a} confinado a limites muy estrechos. Alicia Gaspar de Alba llama a esto The Three Maria Syndrome, que ella define como "the patriarchal social discourse of Chicano/Mexicano culture that constructs women's gender and sexuality according to three Biblical archetypes -virgins, mothers and whores-" (Gaspar de Alba, 2014, pos.3412). Estas representaciones femeninas son alegor{\´i}as a las constricciones que la cultura machista mexicana impone sobre las mujeres, someti{\´e}ndolas a un repertorio restringido de opciones de vida y al control social de su sexualidad. Las mujeres dentro de la narcocultura tienen un lugar en {\´e}l en funci{\´o}n de su belleza f{\´i}sica, el cuerpo es el referente principal para definirse como sujetos. Las mujeres son objetos de deseo, cuya belleza es una joya m{\´a}s para la corona de un narcotraficante, una posesi{\´o}n m{\´a}s para ostentar su poder{\´i}o. Al mismo tiempo, aparecen cada vez m{\´a}s las representaciones femeninas como sujetos activos, participando del negocio y de la violencia a la par de los hombres. Se observan transgresiones al ideal de feminidad que se exige a la mujer tradicional en la cultura mexicana. La docilidad, la suavidad y la sumisi{\´o}n que se espera, el recato y la compostura, no est{\´a} presente. Las mujeres adoptan cualidades consideradas masculinas, tomando para s{\´i} el ejercicio de la violencia y la agresividad sexual para demostrar que ellas tambi{\´e}n pueden navegar un mundo agresivo e hipermasculino. A pesar de esto, esta mujer guerrera y valiente est{\´a} dentro de los confines limitados que la cultura patriarcal impone al r{\´e}gimen heterosexual. Siguen al pie de la letra la prescripci{\´o}n del Three Maria Syndrome. Esto queda patente un sistema de jerarquizaci{\´o}n a trav{\´e}s de la cual se eval{\´u}a a las mujeres dentro de la narcocultura. Las mujeres son juzgadas a partir de criterios que intersectan componentes raciales, de g{\´e}nero y de clase. Aunque las maneras en las que estas marcas de diferencia se encarnan en un cuerpo femenino de manera muy diversa, se puede identificar, a trav{\´e}s de las representaciones y la observaci{\´o}n etnogr{\´a}fica, que las mujeres m{\´a}s privilegiadas, son mujeres que encarnan los signos de una posici{\´o}n econ{\´o}mica alta: tienen tez clara, son atractivas y cuidan su apariencia para presentar signos de feminidad de manera discreta, y su conducta proyecta compostura y respetabilidad, en funci{\´o}n de su restricci{\´o}n, particularmente en la expresi{\´o}n de la sexualidad. A las mujeres que encarnan estos signos de feminidad se les respeta y se consideran valiosas. Su valor se formaliza a trav{\´e}s de la respetabilidad del contrato matrimonial: este tipo de performance de g{\´e}nero lo reproducen, por lo general, mujeres esposas de narcotraficantes. En el otro extremo del espectro est{\´a}n las mujeres menos valoradas: son mujeres morenas, que utilizan una est{\´e}tica asociada con la clase trabajadora, por lo general ostentosa y recargada de decoraciones. La conducta de estas mujeres se juzga como vulgar y sin restricciones. A las mujeres que encarnan este tipo de feminidad se les discrimina y cosifica, son las m{\´a}s vulnerables a la violencia en funci{\´o}n del poco valor que tienen dentro del mundo del narcotr{\´a}fico. La buchona representa una versi{\´o}n devaluada de la feminidad, que choca con el decoro y la discreci{\´o}n que exigen las normas tradicionales de g{\´e}nero. Son mujeres que se consideran vulgares, porque sus cuerpos portan signos de una sexualidad agresiva, porque adoptan conductas que irrumpen las restricciones sociales impuestas a las mujeres, porque sus pr{\´a}cticas y consumos culturales est{\´a}n asociadas a las clases trabajadoras y rurales. En las mujeres que entrevist{\´e} hay un conflicto entre la atractiva libertad que promete la transgresi{\´o}n de ser buchona y el deseo de respetabilidad que otorga ser una mujer que cumple con lo que la sociedad exige. Uno de los dilemas al centro de performar el cuerpo buch{\´o}n es la batalla entre una feminidad aceptada socialmente, pero restrictiva y una feminidad que otorga poder, pero castiga. Por este motivo, las mujeres que entrevist{\´e} rechazaban ser nombradas como buchonas y prefer{\´i}an llamarse a s{\´i} mismas cabronas. En este contexto particular, la palabra cabrona es una resignificaci{\´o}n de un t{\´e}rmino coloquial castellano, usado para ofender. Aqu{\´i}, la mujer cabrona se convierte en un eje articulador para la constituci{\´o}n de subjetividades femeninas dentro de la narcocultura. La cabrona es un tropo femenino que entrelaza narrativas sobre ser mujer que circulan a nivel global con narrativas locales sobre la feminidad. Asumirse "cabrona", se convierte en un recurso para enfrentar un mundo violento y encontrar estrategias de acci{\´o}n en un espacio claramente dominado por los hombres. La cabrona representa independencia y fuerza, autonom{\´i}a y acci{\´o}n. La cabrona confronta los discursos tradicionales de una feminidad abnegada y d{\´o}cil, con diferentes matices, aparentemente interpelando la dominaci{\´o}n masculina. Por lo mismo, carga un fuerte estigma. La cultura de masas tambi{\´e}n produce representaciones sobre la cabrona. Se transmiten en discursos de g{\´e}nero que circulan a trav{\´e}s de im{\´a}genes en las redes sociales, en libros y workshops del mercado de autoayuda en el mundo entero, y que promueven una idea de mujer ind{\´o}cil frente a la gente de su entorno, suscrita al consumo y al individualismo de la cultura capitalista. En estas representaciones culturales contempor{\´a}neas, la mujer es fuerte e insumisa, pero conservando c{\´o}digos corporales y pr{\´a}cticas femeninas. En el contexto concreto de la narcocultura, los discursos globales sobre una mujer fuerte e independiente con poder econ{\´o}mico y a cargo de su sexualidad, se encuentran con las condiciones particulares del norte mexicano. La violencia extrema, el machismo, las desigualdades sociales pronunciadas y la crisis de legitimidad del Estado intervienen para que estos discursos globales sobre la mujer muten en la representaci{\´o}n de la buchona y la cabrona, interpretaciones locales de un discurso de g{\´e}nero global. Para las mujeres, asumirse cabrona es un recurso para enfrentar un mundo violento y encontrar estrategias de acci{\´o}n en un espacio claramente dominado por los hombres. Ayuda a enfrentar la violencia perpetrada sobre ella, abre la posibilidad a ser la victimaria. La cabrona es la reacci{\´o}n que provoca el cuerpo femenino vulnerable y vulnerado, pero tambi{\´e}n, es la posibilidad de apropiarse de la violencia para ejercerla sobre otros cuerpos. Implica independencia, libertad sexual y {\´e}xito econ{\´o}mico, evidenciadas por el consumo y el estilo de vida. Cuando niegan ser buchonas, est{\´a}n rechazando todos los estigmas que acarrea la palabra. No se reconocen en la discriminaci{\´o}n de clase, las connotaciones raciales y los prejuicios sexistas que contiene. Prefieren cabrona porque es una manera de escindirse de los discursos negativos que se vuelcan sobre ellas, es un camino de acceso a una feminidad global que los medios de comunicaci{\´o}n masiva presentan como ideal. El an{\´a}lisis explor{\´o} qu{\´e} elementos compon{\´i}an este tropo femenino a trav{\´e}s de las entrevistas a mujeres y de personajes femeninos en novelas sobre narcotr{\´a}fico, para encontrar puentes entre la ficci{\´o}n y la experiencia vital. La belleza y la capacidad de seducir tiene una utilidad ambivalente. Por un lado, todo el tiempo, dinero y cuidado que se invierte en apropiarse de un ideal est{\´e}tico, es para convertirse en una mujer que un narco pueda presumir. Para las mujeres es un motivo de orgullo saberse deseadas y puestas en aparador. Las mujeres est{\´a}n sometidas a las presiones que genera la creencia de que, para sobrevivir, hay que ser bella. En los textos literarios y en las entrevistas, se transparenta una naturalizaci{\´o}n del lugar de la mujer como objeto de ostentaci{\´o}n para el hombre y, adem{\´a}s, la validaci{\´o}n que sienten las mujeres al ser reconocidas como bellas. La ficci{\´o}n y la vida nos presentan la precaria condici{\´o}n del sujeto femenino en la narcocultura. Es una subjetividad anclada a los discursos que demandan un ideal de belleza imposible para las mujeres y que encajonan el ser mujer a los caprichos y necesidades del hombre. Sin embargo, la belleza femenina tiene otra faceta. La subjetividad femenina en la narcocultura no s{\´o}lo es resultado del sometimiento de la mujer a los discursos que regulan su apariencia y su conducta. La belleza tambi{\´e}n es un instrumento al servicio de las mujeres para acceder a dinero y poder. La belleza y el poder de seducci{\´o}n femenino se convierten en estrategias de subsistencia, y esto transforma a la mujer de un objeto sometido a un sujeto que somete. La belleza y la seducci{\´o}n podr{\´a}n dar a las mujeres ciertos m{\´a}rgenes de acci{\´o}n, pero esto tiene l{\´i}mites muy claros. Aunque estas estrategias femeninas muevan la balanza de poder hac{\´i}a el sujeto femenino, hay que recordar el contexto. Est{\´a}n insertas en un mundo violento y machista, as{\´i} que ejercer ese poder es un ejercicio de equilibrio muy delicado y arriesgado. Las mujeres que habitan la narcocultura est{\´a}n inmersas es un mundo de violencia, y no conocer y respetar las reglas y l{\´i}mites significa un riesgo de muerte. La muerte violenta es una consecuencia muy real por cometer errores en este mundo. Esto lleva a tercer componente de ser cabrona: el riesgo. Para los hombres y mujeres que se involucran en el mundo cultural del narcotr{\´a}fico, perseguir el riesgo es parte integral de vivir y es una parte importante de la constituci{\´o}n de subjetividades en la narcocultura. En las narraciones de las entrevistas y en las narraciones literarias, hay muchos momentos donde las mujeres viven situaciones de riesgo que ponen en peligro hasta sus vidas. A trav{\´e}s de las narraciones se asoma la manera en qu{\´e} ellas interpretan su papel en la situaci{\´o}n y c{\´o}mo se ven a s{\´i} mismas en funci{\´o}n de esas experiencias. El riesgo le da sentido al car{\´a}cter recio y atrevido que demanda asumir el rol de una cabrona, pero tambi{\´e}n expone la vulnerabilidad de la condici{\´o}n de las mujeres en un mundo violento. Tomar riesgos es otra manera de afirmarse como mujeres fuertes y poner distancia con las disposiciones de g{\´e}nero que les exigen ser d{\´o}ciles y pasivas. Tienen que demostrar lo que valen frente a un mundo dominado por hombres y el control de sus emociones juega un rol fundamental en lograr esto. Sin embargo, el reconocimiento del miedo y vulnerabilidad es, parad{\´o}jicamente, lo que las ayuda a sobrevivir. Detr{\´a}s de los discursos de fuerza y poder femenino, se revela la fragilidad de unas vidas sumergidas en un mundo donde la violencia y el machismo deja a las mujeres en el filo de la vida y de la muerte. Para el caso que nos compete, el vac{\´i}o institucional para garantizar seguridad a las mujeres en M{\´e}xico deja a estas mujeres absolutamente expuestas, y cobra sentido la adopci{\´o}n del discurso de la cabrona como estrategia de persistencia. Al investirse como cabronas, encuentran una manera de enfrentarse al mundo violento al que deciden pertenecer, aunque al final de cuentas, permanecen atrapadas en {\´e}l.},
  language  = {es}
}
@phdthesis{Ilic2020,
  author    = {Ilic, Ivan},
  title     = {Design of sustainable cathodes for Li-ion batteries},
  doi       = {10.25932/publishup-48368},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-483689},
  school      = {Universit{\"a}t Potsdam},
  pages     = {iv, 154},
  year      = {2020},
  abstract  = {In recent years people have realised non-renewability of our modern society which relays on spending huge amounts of energy mostly produced from fosil fuels, such as oil and coal, and the shift towards more sustainable energy sources has started. However, sustainable sources of energy, such as wind-, solar- and hydro-energy, produce primarily electrical energy and can not just be poured in canister like many fosil fuels, creating necessity for rechragable batteries. However, modern Li-ion batteries are made from toxic heavy metals and sustainable alternatives are needed. Here we show that naturally abundant catecholic and guaiacyl groups can be utilised to replace heavy metals in Li-ion batteries. Foremost vanillin, a naturally occurring food additive that can be sustainably synthesised from industrial biowaste, lignin, was utilised to synthesise materials that showed extraordinary performance as cathodes in Li-ion batteries. Furthermore, behaviour of catecholic and guiacyl groups in Li-ion system was compared, confirming usability of guiacayl containing biopolymers as cathodes in Li-ion batteries. Lastly, naturally occurring polyphenol, tannic acid, was incorporated in fully bioderived hybrid material that shows performance comparable to commercial Li-ion batteries and good stability. This thesis presents an important advancement in understanding of biowaste derived cathode materials for Li-ion batteries. Further research should be conducted to better understand behaviour of guaiacyl groups during Li-ion battery cycling. Lastly, challenges of incorporation of lignin, an industrial biowaste, have to be addressed and lignin should be incorporated as a cathode material in Li-ion batteries.},
  language  = {en}
}
@phdthesis{Irmscher2020,
  author    = {Irmscher, Tobias},
  title     = {Enzymatic remodelling of the exopolysaccharide stewartan network},
  doi       = {10.25932/publishup-47248},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-472486},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiv, 170},
  year      = {2020},
  abstract  = {In nature, bacteria are found to reside in multicellular communities encased in self-produced extracellular matrices. Indeed, biofilms are the default lifestyle of the bacteria which cause persistent infections in humans. The biofilm assembly protects bacterial cells from desiccation and limits the effectiveness of antimicrobial treatments. A myriad of biomolecules in the extracellular matrix, including proteins, exopolysaccharides, lipids, extracellular DNA and other, form a dense and viscoelastic three dimensional network. Many studies emphasized that a destabilization of the mechanical integrity of biofilm architectures potentially eliminates the protective shield and renders bacteria more susceptible to the immune system and antibiotics. Pantoea stewartii is a plant pathogen which infects monocotyledons such as maize and sweet corn. These bacteria produce dense biofilms in the xylem of infected plants which cause wilting of plants and crops. Stewartan is an exopolysaccharide which is produced by Pantoea stewartii and secreted as the major component to the extracellular matrix. It consists of heptasaccharide repeating units with a high degree of polymerization (2-4 MDa). In this work, the physicochemical properties of stewartan were investigated to understand the contributions of this exopolysaccharide to the mechanical integrity and cohesiveness of Pantoea stewartii biofilms. Therefore, a coarse-grained model of stewartan was developed with computational techniques to obtain a model for its three dimensional structural features. Here, coarse-grained molecular dynamic simulations revealed that the exopolysaccharide forms a hydrogel in which the exopolysaccharide chains arrange into a three dimensional mesh-like network. Simulations at different concentrations were used to investigate the influence of the water content on the network formation. Stewartan was further purified from 72 h grown Pantoea stewartii biofilms and the diffusion of bacteriophage and differently-sized nanoparticles (which ranged from 1.1 to 193 nm diameter) was analyzed in reconstituted stewartan solutions. Fluorescence correlation spectroscopy and single-particle tracking revealed that the stewartan network impeded the mobility of a set of differently-sized fluorescent particles in a size-dependent manner. Diffusion of these particles became more anomalous, as characterized by fitting the diffusion data to an anomalous diffusion model, with increasing stewartan concentrations. Further bulk and microrheological experiments were used to analyze the transitions in stewartan fluid behavior and stewartan chain entanglements were described. Moreover, it was noticed, that a small fraction of bacteriophage particles was trapped in small-sized pores deviating from classical random walks which highlighted the structural heterogeneity of the stewartan network. Additionally, the mobility of fluorescent particles also depended on the charge of the stewartan exopolysaccharide and a model of a molecular sieve for the stewartan network was proposed. The here reported structural features of the stewartan polymers were used to provide a detailed description of the mechanical properties of typically glycan-based biofilms such as the one from Pantoea stewartii. In addition, the mechanical properties of the biofilm architecture are permanently sensed by the embedded bacteria and enzymatic modifications of the extracellular matrix take place to address environmental cues. Hence, in this work the influence of enzymatic degradation of the stewartan exopolysaccharides on the overall exopolysaccharide network structure was analyzed to describe relevant physiological processes in Pantoea stewartii biofilms. Here, the stewartan hydrolysis kinetics of the tailspike protein from the ΦEa1h bacteriophage, which is naturally found to infect Pantoea stewartii cells, was compared to WceF. The latter protein is expressed from the Pantoea stewartii stewartan biosynthesis gene cluster wce I-III. The degradation of stewartan by the ΦEa1h tailspike protein was shown to be much faster than the hydrolysis kinetics of WceF, although both enzymes cleaved the β D GalIII(1→3)-α-D-GalI glycosidic linkage from the stewartan backbone. Oligosaccharide fragments which were produced during the stewartan cleavage, were analyzed in size-exclusion chromatography and capillary electrophoresis. Bioinformatic studies and the analysis of a WceF crystal structure revealed a remarkably high structural similarity of both proteins thus unveiling WceF as a bacterial tailspike-like protein. As a consequence, WceF might play a role in stewartan chain length control in Pantoea stewartii biofilms.},
  language  = {en}
}
@phdthesis{Jelken2020,
  author    = {Jelken, Joachim},
  title     = {Surface relief and bulk birefringence gratings in photo-sensitive polymer films},
  doi       = {10.25932/publishup-48398},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-483988},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiv, 194, lxxxi},
  year      = {2020},
  abstract  = {This thesis is focused on a better understanding of the formation mechanism of bulk birefringence gratings (BBG) and a surface relief gratings (SRG) in photo-sensitive polymer films. A new set-up is developed enabling the in situ investigation how the polymer film is being structured during irradiation with modulated light. The new aspect of the equipment is that it combines several techniques such as a diffraction efficiency (DE) set-up, an atomic force microscope (AFM) and an optical set-up for controlled illumination of the sample. This enables the simultaneous acquiring and differentiation of both gratings (BBG and SRG), while changing the irradiation conditions in desired way. The dissertation is based on five publications. The first publication (I) is focused on the description of the set-up and interpretation of the measured data. A fine structure within the 1st-order diffraction spot is observed, which is a result of the inhomogeneity of the inscribed gratings. In the second publication (II) the interplay of BBG and SRG in the DE is discussed. It has been found, that, dependent on the polarization of a weak probe beam, the diffraction components of the SRG and BBG either interfere constructively or destructively in the DE, altering the appearance of the intensity distribution within the diffracted spot. The third (III) and fourth (IV) publications describe the light-induced reconfiguration of surface structures. Special attention is payed to conditions influencing the erasure of topography and bulk gratings. This can be achieved via thermal treatment or illumination of the polymer film. Using the translation of the interference pattern (IP) in a controlled way, the optical erase speed is significantly increased. Additionally, a dynamic reconfigurable surface is generated, which could move surface attached objects by the continuous translation of the interference pattern during irradiation of the polymer films. The fifth publication (V) deals with the understanding of polymer deformation under irradiation with SP-IP, which is the only IP generating a half-period topography grating (compared to the period of the IP) on the photo-sensitive polymer film. This mechanism is used, e.g. to generate a SRG below the diffraction limit of light. It also represents an easy way of changing the period of the surface grating just by a small change in polarization angle of the interfering beams without adjusting the optical pass of the two beams. Additionally, complex surface gratings formed in mixed polarization- and intensity interference patterns are shown. I J. Jelken, C. Henkel and S. Santer, Applied Physics B, 125 (2019), 218 II J. Jelken, C. Henkel and S. Santer, Appl. Phys. Lett., 116 (2020), 051601 III J. Jelken and S. Santer, RSC Advances, 9 (2019), 20295 IV J. Jelken, M. Brinkjans, C. Henkel and S. Santer, SPIE Proceedings, 11367 (2020), 1136710 V J. Jelken, C. Henkel and S. Santer, Formation of Half-Period Surface Relief Gratings in Azobenzene Containing Polymer Films (submitted to Applied Physics B)},
  language  = {en}
}
@phdthesis{KaramzadehToularoud2020,
  author    = {Karamzadeh Toularoud, Nasim},
  title     = {Earthquake source and receiver array optimal configuration},
  doi       = {10.25932/publishup-45982},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459828},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 94},
  year      = {2020},
  abstract  = {Seismic receiver arrays have variety of applications in seismology, particularly when the signal enhancement is a prerequisite to detect seismic events, and in situations where installing and maintaining sparse networks are impractical. This thesis has mainly focused on the development of a new approach for seismological source and receiver array design.The proposed approach deals with the array design task as an optimization problem. The criteria and prerequisite constraints in array design task are integrated in objective function definition and evaluation of a optimization process. Three cases are covered in this thesis: (1) a 2-D receiver array geometry optimization, (2) a 3-D source array optimization, and (3) an array application to monitor microseismic data, where the effect of different types of noise are evaluated. A flexible receiver array design framework implements a customizable scenario modelling and optimization scheme by making use of synthetic seismograms. Using synthetic seismograms to evaluate array performance makes it possible to consider additional constraints, e.g. land ownership, site-specific noise levels or characteristics of the seismic sources under investigation. The use of synthetic array beamforming as an array design criteria is suggested. The framework is customized by designing a 2-D small scale receiver array to monitor earthquake swarm activity in northwest Bohemia/ Vogtland in central Europe. Two sub-functions are defined to verify the accuracy of horizontal slowness estimation; one to suppress aliasing effects due to possible secondary lobes of synthetic array beamforming calculated in horizontal slowness space, and the other to reduce the event's mislocation caused by miscalculation of the horizontal slowness vector. Subsequently, a weighting technique is applied to combine the sub-functions into one single scalar objective function to use in the optimization process. The idea of optimal array is employed to design a 3-D source array, given a well-located catalog of events. The conditions to make source arrays are formulated in four objective functions and a weighted sum technique is used to combine them in one single scalar function. The criteria are: (1) accurate slowness vector estimation, (2) high waveform coherency, (3) low location error and (4) high energy of coda phases. The method is evaluated by two experiments, (1) a synthetic test using realistic synthetic seismograms, (2) using real seismograms, and for each case optimized SA elements are configured using the data from the Vogtland area. The location of a possible scatterer in the velocity model, that makes the converted/reflected phases, e.g. sp-phases, is retrieved by a grid search method using the optimized SA. The accuracy of the approach and the obtained results demonstrated that the method is applicable to study the crustal structure and the location of crustal scatterers when the strong converted phases are observed in the data and a well-located catalog is available. Small aperture arrays are employed in seismology for a variety of applications, ranging from pure event detection to monitor and study of microcosmic activities. The monitoring of microseismicity during temporary human activities is often difficult, as the signal-to-noise ratio is very low and noise is strongly increased during the operation. The combination of small aperture seismic arrays with shallow borehole sensors offers a solution. We tested this monitoring approach at two different sites, (1) accompanying a fracking experiment in sedimentary shale at 4~km depth, and (2) above a gas field under depletion. Arrays recordings are compared with recordings available from shallow borehole sensors and examples of detection and location performance of the array are given. The effect of different types of noise at array and borehole stations are compared and discussed.},
  language  = {en}
}
@phdthesis{Kaya2020,
  author    = {Kaya, Mustafa},
  title     = {Cretaceous-Paleogene evolution of the proto-Paratethys Sea in Central Asia},
  doi       = {10.25932/publishup-48329},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-483295},
  school      = {Universit{\"a}t Potsdam},
  pages     = {iv, 237},
  year      = {2020},
  abstract  = {Unlike today's prevailing terrestrial features, the geologic past of Central Asia witnessed marine environments and conditions as well. A vast, shallow sea, known as proto-Paratethys, extended across Eurasia from the Mediterranean Tethys to the Tarim Basin in western China during Cretaceous to Paleogene times. This sea formed about 160 million years ago (during Jurassic times) when the waters of the Tethys Ocean flooded into Eurasia. It drastically retreated to the west and became isolated as the Paratethys during the Late Eocene-Oligocene (ca. 34 Ma). Having well-constrained timing and paleogeography for the Cretaceous-Paleogene proto-Paratethys sea incursions in Central Asia is essential to properly understand and distinguish the controlling mechanisms and their link to Asian paleoenvironmental and paleoclimatic change. The Cretaceous-Paleogene tectonic evolution of the Pamir and Tibet and their far-field effects play a significant role on the sedimentological and structural evolution of the Central Asian basins and on the evolution of the proto-Paratethys sea fluctuations as well. Comparing the records of the sea incursions to the tectonic and eustatic events has paramount importance to reveal the controlling mechanisms behind the sea incursions. However, due to inaccuracies in the dating of rocks (mostly continental rocks and marine rocks with benthic microfossils providing low-resolution biostratigraphic constraints) and conflicting results, there has been no consensus on the timing of the sea incursions and interpretation of their records has been in question. Here, we present a new chronostratigraphic framework based on biostratigraphy and magnetostratigraphy as well as a detailed paleoenvironmental analysis for the Cretaceous and Paleogene proto-Paratethys Sea incursions in the Tajik and Tarim basins, in Central Asia. This enables us to identify the major drivers of marine fluctuations and their potential consequences on regional and global climate, particularly Asian aridification and the global carbon cycle perturbations such as the Paleocene-Eocene Thermal Maximum (PETM). To estimate the paleogeographic evolution of the proto-Paratethys Sea, the refined age constraints and detailed paleoenvironmental interpretations are combined with successive paleogeographic maps. Regional coastlines and depositional environments during the Cretaceous-Paleogene sea advances and retreats were drawn based on the results of this thesis and integrated with existing literature to generate new paleogeographic maps. Before its final westward retreat in the Eocene, a total of six Cretaceous and Paleogene major sea incursions have been distinguished from the sedimentary records of the Tajik and Tarim basins in Central Asia. All have been studied and documented here. We identify the presence of marine conditions already in the Early Cretaceous in the western Tajik Basin, followed by the Cenomanian (ca. 100 Ma) and Santonian (ca. 86 Ma) major marine incursions far into the eastern Tajik and Tarim basins separated by a Turonian-Coniacian (ca. 92-86 Ma) regression. Basin-wide tectonic subsidence analyses imply that the Early Cretaceous invasion of the sea into the Tajik Basin is related to increased Pamir tectonism (at ca. 130 - 90 Ma) in a retro-arc basin setting inferred to be linked to collision and subduction. This tectonic event mainly governed the Cenomanian (ca. 100 Ma) sea incursion in conjunction with a coeval global eustatic high resulting in the maximum geographic extent of the sea. The following Turonian-Coniacian (ca. 92-86 Ma) major regression, driven by eustasy, coincides with a sharp slowdown in tectonic subsidence related to a regime change in Pamir tectonism from compression to extension. The Santonian (ca. 86 Ma) major sea incursion was more likely controlled dominantly by eustasy as also evidenced by the coeval fluctuations in the west Siberian Basin. During the early Maastrichtian, the global Late Cretaceous cooling is inferred from the disappearance of mollusk-rich limestones and the dominance of bryozoan-rich and echinoderm-rich limestones in the Tajik Basin documenting the first evidence for the Late Cretaceous cooling event in Central Asia. Following the last Cretaceous sea incursion, a major regional restriction event, marked by the exceptionally thick (≤ 400 m) shelf evaporites is assigned a Danian-Selandian age (ca. 63-59 Ma). This is followed by the largest recorded proto-Paratethys sea incursion with a transgression estimated as early Thanetian (ca. 59-57 Ma) and a regression within the Ypresian (ca. 53-52 Ma). The transgression of the next incursion is now constrained as early Lutetian (ca. 47-46 Ma), whereas its regression is constrained as late Lutetian (ca. 41 Ma) and is associated with a drastic increase in both tectonic subsidence and basin infilling. The age of the final and least pronounced sea incursion restricted to the westernmost margin of the Tarim Basin is assigned as Bartonian-Priabonian (ca. 39.7-36.7 Ma). We interpret the long-term westward retreat of the proto-Paratethys Sea starting at ca. 41 Ma to be associated with far-field tectonic effects of the Indo-Asia collision and Pamir/Tibetan plateau uplift. Short-term eustatic sea level transgressions are superimposed on this long-term regression and seem coeval with the transgression events in the other northern Peri-Tethyan sedimentary provinces for the 1st and 2nd Paleogene sea incursions. However, the last Paleogene sea incursion is interpreted as related to tectonism. The transgressive and regressive intervals of the proto-Paratethys Sea correlate well with the reported humid and arid phases, respectively in the Qaidam and Xining basins, thus demonstrating the role of the proto-Paratethys Sea as an important moisture source for the Asian interior and its regression as a contributor to Asian aridification. We lastly study the mechanics, relative contribution and preservation efficiency of ancient epicontinental seas as carbon sinks with new and existing data, using organic rich (sapropel) deposits dated to the PETM from the extensive epicontinental proto-Paratethys and West Siberian seas. We estimate ca. 1390±230 Gt organic C burial, a substantial amount compared to previously estimated global total excess organic C burial (ca. 1700-2900 Gt) is focused in the proto-Paratethys and West Siberian seas alone. We also speculate that enhanced organic carbon burial later over much of the proto-Paratethys (and later Paratethys) basin (during the deposition of the Kuma Formation and Maikop series, repectively) may have majorly contributed to drawdown of atmospheric carbon dioxide before and during the EOT cooling and glaciation of Antarctica. For past periods with smaller epicontinental seas, the effectiveness of this negative carbon cycle feedback was arguably diminished, and the same likely applies to the present-day.},
  language  = {en}
}
@phdthesis{Khalfa2020,
  author    = {Khalfa, Zehava},
  title     = {מאירועי ההתנתקות ועד לאירועי - תג מחיר},
  doi       = {10.25932/publishup-47446},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-474465},
  school      = {Universit{\"a}t Potsdam},
  pages     = {180, יז},
  year      = {2020},
  abstract  = {תקציר העבודה בערב יום העצמאות 1967, שבועות אחדים ערב מלחמת ששת הימים זעק הרב צבי יהודה קוק (1891-1982) "איפה חברון שלנו - אתם שוכחים את זה?! ואיפה שכם שלנו - אנחנו שוכחים את זה?! ואיפה עבר הירדן שלנו איפה כל רגב ורגב? כל חלק וחלק, של ארבע אמות ארץ ד'. הבידינו לוותר על איזה מילימטר מהן? חלילה וחס ושלום" דבריו הנחרצים של הרב, יחד עם כיבוש שטחי הגדה המערבית, חברון שכם וירושלים כמו גם חצי האי סיני ורצועת עזה במהלך ששת ימי הלחימה ביוני 1967, הביאו להתפרצות העוצמתית ביותר של תחושת פעמי משיח בקרב הציבור הציוני דתי. וכפי שצויין בדבריו של הרב ישראל אריאל, בואו של המשיח היה עניין של שעות אחדות. אולם כעשר שנים מאוחר יותר בשנת 1978, חתמה ממשלת ישראל על הסכם שלום עם מצרים. במסגרת הסכם השלום, הוחזרו כל שטחי חצי האי סיני לידי המצרים ופורקה ההתיישבות בחבל ימית . תושבי חבל ימית נעקרו מבתיהם (בהם התגוררו משנת 1971- אפריל 1982). גם הציבור הציוני דתי נאלץ למצוא הסברים לכך שמדינת ישראל פועלת בניגוד לציפיות שנתלו בה מבחינת היותה אבן דרך בדרך לגאולה. תלמידיו של הרב צבי יהודה קוק, שרובם כבר החזיקו במשרות רבניות. חוו את חוויית העקירה בשיא פועלם. הרב צבי ישראל טאו, מתלמידיו הקרובים של הרב צבי יהודה קוק, אסר על תלמידיו להשתתף בהפגנות. הוא פסק כי חייבים לכבד את החלטת הממשלה שנבחרה על ידי רוב יהודי. הוא דבק בדבריו של הרב צבי יהודה קוק כשאמר "העם לא איתנו" ו"דינא דמלכותא דינא" בייחוד כשמדובר בממשלה יהודית הנבחרת על העם. אולם השבר הגדול, כפי שמוטי ענברי כתב "the profound theological crisis " היה ההתנתקות מרצועת עזה בשנת 2005. הקושייה היתה - האם מדינה שעוקרת התיישבות יהודית ומוסרת שטחים מארץ ישראל לידי אויביה, יכולה עוד להיקרא מדינה קדושה. הדיסוננס הקוגניטיבי במסגרת ההתנתקות מרצועת עזה כדי להבין את משבר ההתנתקות - יש לחלקו לשניים. האחד: המשבר האמוני כלפי המדינה - הציבור הציוני דתי החזיק באמונה כי זאת המדינה שהיא "יסוד כיסא השם בעולם" וזאת המדינה "אותה חזו הנביאים " (דבריו של הרב צבי יהודה קוק בעקבות אכזבתו מהעדרם של המקומות הקדושים בשטחה של מדינת ישראל, לפני מלחמת ששת הימים). והמשבר השני הוא: המשבר האמוני כלפי האלוקות אשר "איפשרה" לתוכנית זאת לצאת לפועל. ישנו, אם כן, את הקונפליקט כלפי החלטות המדינה החילונית הקיימת לבין התפיסה האמונית המתעקשת לראות אותה כמדינה קדושה. וכן הקונפליקט כלפי האמונה בה הם מחזיקים - אשר לפיה, עם ישראל נמצא בשעת גאולה וזו הולכת ומתעצמת לקראת בואו של המשיח. לפי תפיסת מציאות אמונית זו - תוכנית ההתנתקות אינה אמורה להתממש כלל. וזו אכן התממשה. אם כן, כיצד התגבר ציבור זה ושיקם את התפיסה האמונית שלו כלפי האלוקות, זאת שאלה אחת. והשאלה השניה כיצד הוא שיקם את יחסו כלפי המדינה, והאם הוא עדיין רואה בה את "זאת המדינה שחזו הנביאים". השתמשתי בתיאוריית הדיסוננס הקוגניטיבי של ליאון ופסטינגר ועמיתיו כדי לנתח ולהעריך את המשבר האמוני שעבר ציבור זה. מאמריו של ענברי וניתוחו את המשבר האמוני שחל בקרב הציבור הדתי ציוני בתום תוכנית ההתנתקות. שימשו גם כן כלי בעבודה זו, על מנת להעריך את ההתפתחויות הנוספות שחלו בקרב הציבור הזה במלאת עשר שנים מאז מימוש תוכנית ההתנתקות. כמו גם הופעת אירועי האלימות והטרור המכונים "אירועי תג מחיר". לפי חמשת העקרונות של פסטינגר ועמיתיו ניתן לצפות שחברי קבוצה כלשהיא יגבירו את להט האמונה בעקבות הפרכת אמונתם, כלומר "כישלון הנבואי" במידה ומתקיימים חמשת התנאים הבאים: 1. על האמונה לנבוע מתוך שכנוע עמוק ועליה להיות רלונטית לפעולה שהמאמין עושה או איך שהוא מתנהג, 2. המאמין, האדם המחזיק באמונה זו חייב למסור את עצמו למענה, עליו לבצע החלטות חשובות שלא ניתן לבטלם. ככל שהפעולות חשובות יותר, וככל שקשה יותר לבטלם, כך גדלה בהתאמה המחוייבות של הפרט לאמונה. לדוגמא: להתפטר מעבודה, לעבור דירה. 3. האמונה חייבת להיות ספציפית למדי ומעורבת מספיק במציאות כך שאירועים מציאותיים יכולים באופן חד משמעי להפריך את האמונה. 4. אירוע הסותר את האמונה חייב להתרחש ולהיות מזוהה על ידי הפרט המאמין. 5. המאמין חייב לקבל תמיכה חברתית, כמעט לא יתכן שפרט מאמין מבודד יכול יהיה לעמוד בפני ראיות סותרות שהדגשנו מעלה. בהנתן חמשת התנאים האלו, יש לצפות שהפרט המאמין -החבר בקבוצה של פרטים המשוכנעים באמונתם ויכולים לתמוך אחד בשני, ימשיך להחזיק באמונתו באופן יציב, ובנוסף, הוא וחבריו ימשיכו לגייס מאמינים חדשים. אולם בניגוד למקרים שנבחנו על ידי פסטינגר ועמיתיו, תוכנית ההתנתקות מרצועת עזה, התאפיינה בכך שתאריך הפינוי לא נקבע על ידי מנהיגי הציבור הציוני דתי, אלא על ידי ראש ממשלת ישראל דאז אריאל שרון. הוא החליט יחד עם ממשלת ישראל על פינוי רצועת עזה ב15 באוגוסט 2005 (י' באב תשס"ה) מכל תושביה היהודים, פירוק הבסיסים הצבאיים וחיסול כל סממן של ריבונות ישראלית בה. יש כאן בעצם, תמונת תשליל, אירוע קיצוני עם תאריך יעד מוגדר שהציבור הציוני דתי נלחם כדי לבטלו. תגובות הרבנים, תגובות שנבחנו על פי תיאוריית הדיסוננס הקוגניטיבי של המתנחלים לפני הנסיגה ולאחריה בעבודה, בחנתי את תיאולוגיות רבני הציונות הדתית הפעילים ביותר בתקופה מדוברת זו והם: הרב דב ליאור, הרב זלמן מלמד, הרב צבי ישראל טאו, הרב חנן פורת ז"ל והרב שלמה אבינר. התיאולוגיות נבחנו לפני ההתנתקות ולאחריה, כמו גם עשר שנים לאחר ההתנתקות. בין השאלות שנבחנו הם: כיצד השתנה היחס לממלכתיות, האם יש חובה לסרב פקודה, כיצד הם נימקו את הגזירה לציבור תלמידיהם. בנוסף לכך, נבחנה תופעת ה"תג מחיר", בדקתי האם היא תוצאה ממשבר ההתנתקות מרצועת עזה או המשך ישיר של התפתחות "תנועת גוש אמונים" וההתמודדיות היומיומית בין המדינה הממשית החילונית לבין המדינה הדתית האוטופית, אליה הם שואפים. כמו כן בחנתי את יחסם של הרבנים כלפי הפעילים בטרור זה, כלפי הפלסטינים וכלפי הצבא. הרב דב ליאור הרב דב ליאור, היה רב הישוב קרית ארבע - חברון וראש ישיבת ההסדר ניר שבמקום. נולד בשנת 1933 בירוסלב בגליציה למשפחת חסידי בעלז, בשנת 1939 עם פרוץ הכוחות הגרמניים לפולין, נמלטה משפחתו לרוסיה. בשנת 1948 עלה באוניית המעפילים "נגבה" לארץ ישראל, ובשנת 1949 עבר לישיבת "מרכז הרב" בירושלים, ולמד עם הרב צבי יהודה קוק. הרב ליאור היה הרב הראשון שנשלח על ידי הרב צבי לכהן כרב הישוב כפר הרא"ה, ומאוחר יותר עבר לקריית ארבע, שם הוא כיהן כרב היישוב עד לפרישתו. גישתו להחלטה על ההתנתקות מרצועת עזה היתה: "אחרי עשרות שנים של חוסר חינוך" תוצאה היא -"התנתקות מארץ ישראל". אולם על הציבור הציוני דתי: "לבלום את הרשעות הזאת. [...] אם זה יבוצע זה עלול לפגוע בקיומנו כעם וקיומנו כמדינה". הדרך להיאבק לשיטתו היא: "בהתנגדות פסיבית". למרות שהציבור הציוני דתי הוא ממלכתי "דינא דמלכותא דינא" אבל לא דבר שכנגד תורת ישראל, אם ממשלת ישראל מחליטה להרוס ישוב ולהסגיר שטח לידי האויב, יש להראות זאת כגזירה וצריכים לעמוד כנגד זה מכל המשתמע מכך. [...] הם יכולים לקבוע בענייני מיסים, מהירות הנסיעה. החזון, לפי הרב ליאור הוא ש "לא ירחק היום והציבור שלנו יחליט בכל מערכות החיים הציבוריים, במשפט בכלכלה. לדעתו: "מערכת המשפט זה החילול הגדול שיותר שיש במדינה. להתכונן לקראת הנהגת עם ישראל ואם הציבור שלנו יקח את ההנהגה יהיה שלום אמת, אימתם של ישראל תהיה מוטלת על כל המחבלים ותורת ישראל ברוחה והשפעתה תהיה ניכרת בכל תחומי חיינו הציבוריים. נעבור את התקופה הקשה הזאת ולא ניפול ביאוש ונזכה לראות בישועת ה'" . מצד אחד הרב ליאור קרא למאבק שהכלים שלו אינם סטדנדרטים שדרש שלא ללכת כמו צאן ולקרוא על החלטות הכנסת "קדוש". ומצד שני הוא קרא למאבק פסיבי. מאחרית דבריו של הרב ליאור במאמר לעיל בפסקה האחרונה, ניכר כי הוא השלים עם הגזירה של תוכנית ההתנתקות ונותר רק לקרוא לציבור הציוני דתי לקחת את ההנהגה לידיים. לאחר ההתנתקות כחודש לאחר ההתנתקות, בכנס שנערך ב- ג' באלול תשס"ה, הביע הרב ליאור את דעתו. הוא נתן במה לשאלות ולטרדות שקיימות בקרב הציבור הציוני דתי, כמו איך להתייחס למדינה, האם להתנתק ממנה, האם יש צורך לפשפש במעשינו, לחזור בתשובה? "ומכאן עולות שאלות כבדות משקל: האם אנחנו חטאנו, האם אנשי הגוש חטאו, האם עם ישראל חטא. אנחנו מחפשים מהי בדיוק נקודת החולשה, לא מתוך כוונה להטיל אשמות במישהו, אלא כדי לדעת לתקן." הוא הוסיף כי: "מי שחש את פעמי הגאולה, לא ייפול בייאוש ובחולשת הדעת גם במצבים של מעין נסיגה. לא נאבד בגלל זה את האמון שלנו במהלך האלוקי הגדול של שיבת עם ישראל לארצו. כמו כן, הרב ליאור כתב בגליון י' של ירחון „קומי אורי" בעקבות המלחמה בלבנון השניה בשנת 2006: "אין לי ספק שהיסורים הקשים שפוקדים את עמנו במלחמה הזאת, שנמשכה למעלה מחודש, באו בעקבות הפשע החמור לפני כשנה, הגליית היהודים מגוש קטיף, החרבת ביתם והסגרת חבלי ארץ לידי אויב " לפי הרב ליאור אין צורך בתשובה או היטהרות, או חזרה לערכים שננטשו, אלא הסבר תכליתי מחודש לאירוע ה'הכישלון הנבואי'. מדבריו של הרב ליאור לפני ההתנתקות, הוא הניח שתוכנית ההתנתקות יכולה להתבטל, וזה תלוי במאבק של מיישמי התוכנית, כלומר החיילים והמפקדים. במידה והם יסרבו פקודה, אז התוכנית תתבטל. הרב זלמן ברוך מלמד הרב זלמן ברוך מלמד, נולד בתל אביב בשנת 1937. הוא ראש ישיבת בית אל וממקימי ערוץ 7 ואתר האינטרנט Yeshiva, אתר האינטרנט הראשון להפצת שיעורי תורה של רבני הציונות הדתית. הוא למד בישיבת "מרכז הרב" אצל הרב צבי יהודה קוק משנת 1954. לאחר כעשר שנים כתלמידו הקרוב, הוא התמנה לר"מ (רב ומלמד) בישיבה. בשנת 1978 נשלח בתמיכת הרב צבי יהודה קוק להקים ישיבה בבסיס הצבאי שליד בית אל. מאוחר יותר הוקמה במקום ההתנחלות בית אל. לפי גישתו, המאבק על גוש קטיף הוא מאבק סמוי שיש בין שני חלקי העם: "אין כאן הבדלים פוליטים של הערכות מדיניות אם הצעד הזה נכון או לא נכון. לא זו המחלוקת, אלא איזה מהות תהיה למדינה - מדינה לכל אזרחיה חסרת זהות או מדינה יהודית בעלת תוכן יהודי" . הוא ציין שמדובר ב"משבר זהות הציונות", משבר שחל בקרב חלק מהציבור וכעת מתנהל מאבק בין שני חלקי ציבור זה. יחסו לסירוב פקודה היה ברור: "ואני אומר לצבא ולשוטרים, אם תכשלו ולא תוכלו לעקור את הישובים, הצלחתם. אתם יכולים כבר עכשיו לומר שזו משימה בלתי אפשרית וכבר עכשיו להצליח, צה"ל לא צריך לנצח את היהודים, צה"ל צריך לנצח את האוייב." הרב מלמד קרא לשוטרים וחיילים לסרב פקודה על מנת לעשות הכל כדי לסכל את תכנית ההתנתקות. לפי גישתו האמונית: "המכות האלו שאנו מקבלים הם מפני שהשקפת השמאל החילוני מתרסקת, אין קיום לעם ישראל בלי אמונה, ותוך כדי פרפורי הגסיסה של השמאל הוא מכה בכוחותיו האחרונים. לאחר מכן תקום הנהגה יהודית אמונית שתוביל את המדינה לקראת הגאולה " הרב חנן פורת (1943-2011) חנן פורת היה ממייסדי תנועת "גוש אמונים". הוא הגיע לכפר עציון עם משפחתו בשנת 1943 בהיותו בן חצי שנה. המשפחה פונתה מכפר עציון בהיותו כבן שש בתחילת מלחמת העצמאות, 1948. מאוחר יותר למד חנן פורת מספר שנים בישיבת "כרם ביבנה", לפני שעבר יחד עם גרעין הגחלת לישיבת "מרכז הרב". שם למד עם הרב צבי יהודה קוק. בשנת 2000 ייסד הרב פורת את עלון פרשת השבוע "מעט מן האור", בו פירסם חידושי תורה. העלון חולק חינם בבתי כנסת בכניסת השבת והופיע עד שנת 2014 (כשלוש שנים לאחר מותו). תגובתו לפני ההתנתקות: "אנו קוראים לכל הדבקים בארץ ישראל, ולכל המאמינים בחי-עולמים וזורעים: אל תגררו אחרי קמפיין-תקשורתי זה שכל מגמתו להעצים את הציפיה ל'יום פקודה' ולקובעו כעובדה מוגמרת כבר עתה. [...] אנחנו ממשיכים יום יום לנטוע ולזרוע, ובזכותם יהפוך בעזרת ה' יתברך יום הפקודה, מיום 'בשורת איוב' ליום 'בשורת גאולה'." הרב פורת קרא להמשיך ולפעול כרגיל ולא להתייחס להוראות הפינוי על כל סעיפיהם, (פנייה למנהלת ההתנתקות על מנת להסדיר מקום חלופי כמו גם אומדן הרכוש לצורך קבלת כספי הפיצויים). הוא התנגד לאלימות, והסביר כי פעולות אלימות נובעות מכעס שאין לו מקום: "שלטון הכעס על האדם הריהו חלילה בבחינת שלטון זר של אל נכר" בעלון הראשון של הגליון "מעט מן האור" אשר הופיע זמן קצר אחרי ההתנתקות, באה לידי ביטוי תגובת האבל החריפה על האובדן של ההתיישבות בגוש קטיף, אך יחד איתה גם נבואת נחמה: "עשינו מה שגזרת עלינו, עשה אתה מה שעליך לעשות!" "בחסדי ה' יתברך עוד נשוב לגוש קטיף לבנות ולהבנות בו, חרף הייסורים שראו עלינו מידי אדם ובשובנו בשנית...והפכתי אבלם למחול ושימחתים מיגונם" (ירמיה ל"א ז-יב) . אכזבתו ממוסדות המדינה בעקבות הגירוש, בא לידי ביטוי בעלון שיצא כחודש לאחר ההתנתקות. "הריקבון הזה - שפשה בכל רקמות השלטון, מחייב אותנו לחשבון נפש עמוק ונוקב, באשר ליחסינו לכל הנהגת המדינה, ולא רק כלפי העומד בראשה." במלאות חמש שנים להתנתקות, הוא התייחס לכישלון המאבק בשיחה שהתנהלה בדצמבר 2009 ב"מכון מאיר" בין הרב פורת לבין חגי לונדין. בשיחה - "הוא הירבה להתייחס לפסוק "ושבו בנים לגבולם" שהינו חלק מנבואת הנביא ירמיהו לגבי שיבת עם ישראל לארצו. "התגשמות החלום של ילדי כפר עציון שידענו שיום יבוא ואנחנו נשוב". "עקירת הישובים היא פצע פתוח שותת דם. כדאי לא לשכוח שמעבר לפגיעה בזכויות האדם, היא העובדה כאילו סטרו בפרצופה של רחל שאלוקים הבטיח לה בנבואה "ושבו בנים לגבולם"". מבחינתו של פורת - הציונות החילונית היתה מבחינת החוצפה כלפי שמיים, של "אנחנו נעקור בנים מגבולם". הרב שלמה חיים אבינר ראש ישיבת עטרת ירושלים, השוכנת ברובע היהודי וגם רב הישוב "בית אל" א', נולד בצרפת בשנת 1943 ועלה לישראל בשנת 1966. לאחר שירותו הצבאי הצטרף לישיבת "מרכז הרב". לאחר מלחמת ששת הימים, הצטרף לקבוצה ששהתה במלון "פארק" במטרה לחדש את הישוב היהודי בחברון (אפריל 1968). לימים, רב הישוב קשת ברמת הגולן. ומשנת 1981 ועד היום, רב הישוב "בית אל" א'. מבחינת הרב אבינר התגשמות הגאולה הארצית חלה על ידי ייסודה של מדינת ישראל ומוסדותיה על אדמות ארץ ישראל. הוא הדגיש ומדגיש את "קדושת הממלכתיות", וזאת באה לידי ביטוי ביחסו לצבא, להחלטות הממשלה ולחוקיה. מבחינתו אלה הם בגדר קודש, שאין לערער עליו. אולם מצד שני, הוא קרא לסרבנות אזרחית, לא לשתף פעולה אזרחית עם מנהלת ההתנתקות בכל שלבי הפינוי. ואף קרא לחרם צרכני על אותם אזרחים המשתפים פעולה עימה. בפרק על הרב אבינר בעבודת הדוקטורט, התייחסתי גם לנושא 'מסירות הנפש'. נושא שהתמלא בתוכן חדש, זאת לראשונה על ידי הרב צבי יהודה קוק ותלמידיו. למרות שהרב אבינר ראה את עצמו כרב בעל גישה ממלכתית ולא פסל את הקריאה לסרבנות. הוא היה בין הכוחות המסייעים אקטיבית להרגעת הציבור המפונה, כשתפקידו היה למנוע את ההתנגדות לפינוי. בנוסף לכך, הרב אבינר קרע את בגדי הציבור המפונה, לאות אבל. הרב צבי ישראל טאו לפי תיאולוגיית הרב טאו, שורש הסיבה לגזירת ההתנתקות היא ההתנתקות מהחילונים, אותם הוא מכנה "המנותקים מן הקודש". אנשים שמבחינתו שייכים לעם ישראל, אך ריקים בתוכנם ולכן האובססיה שהם גילו כלפי תוכנית ההתנתקות מהווה עבורם חלופה לאובססיה דתית: "רוממות הרוח שבאה בעקבות 'מלחמת ששת הימים' שככה במהרה, ואת מקומה תפסו הספקנות וחוסר הודאות בכל השייך לענייננו הלאומי. [...] כיצד נקלענו לשבר אידיאלוגי כה עמוק עד כדי 'פוסט ציונות' מוצהרת ועד כדי 'תוכנית ההתנתקות' בימינו". לפי הרב טאו יש חשיבות גדולה להבנה, שהעולם בשיח תמידי המתנהל פנים מול פנים. כלומר ברגע שישנו ניתוק בעם מן התכלית האמיתית, אזי מאיימת תוכנית התנתקות חיצונית. וזאת אמורה לעורר את האומה כולה לחשיבה מחודשת לחזרה לעקרונות, וממנה לעשייה. "לכן, לא בחסימת כבישים ובהפגנות אלימות וכוחניות נהיה פועלים עם אל לישועת עמנו, פעולה זו מתייחסת לסימפטומים ולתופעות החיצוניות ולא לשורשיהן וסיבותיהן, וכמוה כנשיכת הכלב את המקל". הוא המליץ לתלמידיו, להתרחק מן הזעם (הפגנות וחסימת כבישים) ומהיאוש: "התמלאות בזעם וביאוש מזיקה לכל המצב הכללי, ומוסיפה נפילה על נפילה. התייחסותו לסירוב פקודה: הרב טאו התנגד לסירוב הפקודה, מאחר ולהשקפתו אין לנשוך במקל המכה, אלא להאבק בשורש הבעיה, שהיא הניתוק בעם. אלא שככל שתוכנית ההתנתקות קרבה למועדה המתוכנן, חל שינוי בהשקפתו. החוקר יאיר שלג, התייחס לשינוי הזה במאמר שפירסם ב"הארץ": "הסרבנות האפורה של הרב טאו" לפיה: "סרבנות מפורשת אכן אסורה, אבל על התלמידים להבהיר למפקדיהם ש"אינם מסוגלים" למלא פקודה מעין זו." הרב טאו קרא למאמיניו תלמידיו ותומכיו שלא להתנגד לסירוב פקודה, אלא להמנע מקיום הפקודה. ומדברים שפורסמו כעשר שנים לאחר ההתנתקות בהם אמר הרב "לא היינו צריכים להיות בהתנתקות". הרב טאו האמין גם כן שלהתנתקות יש סיכוי טוב להתבטל, אם השורש והבסיס לקיומה יתבטל. כלומר, הוא האמין ביכולתו של הפרט בקבוצה לפעול למען כישלון תוכנית ההתנתקות. קריאתו של הרב טאו לפעולות "פנים אל פנים" על מנת לקרב את עם ישראל לאידיאולוגיה שלו, אפשר לראותה כקריאה לגיוס מאמינים, אולם קריאה זו נשארה רק בין כתלי בית המדרש. כעשר שנים לאחר ההתנתקות מרצועת עזה מסיכום הממצאים בעבודה זו, יש לציין כי - גם הרבנים שקראו לסירוב פקודה וגם הרבנים שקראו לכבד את החלטת הממשלה יישרו קו בסופו של דבר והם רואים את תוכנית ההתנתקות כמשבר מקומי. כמעט כל הרבנים, מלבד הרב טאו- טוענים שיש לראות את התמונה כולה שהיא בכללה חיובית. שהרי ההתיישבות היהודית ממשיכה להתרחב כמו גם עולם התורה ועולם הישיבות. הרב חנן פורת ז"ל האמין שעם ישראל עוד יחזור למקומות מהם הוא גורש, כפי שקרה בעבר עם משפחתו אשר גורשה מכפר עציון. הרב זלמן מלמד אמר במספר ניסוחים: "יש פה ושם צרה, אך החיבור שלנו לארץ-ישראל לא נעצר מלכת והוא הולך ומתחזק. הארץ נבנית בגליל ובנגב, בשרון ובשומרון ובכל רחבי ארץ-ישראל. יש מקומות שיש עליהם מאבק, אבל בסך הכול ההתרחבות וההתקדמות לא נעצרו" הרב דב ליאור: "לא נאבד בגלל זה את האמון שלנו במהלך האלוקי הגדול של שיבת עם ישראל לארצו" . הרב אבינר: "אך כאמור איננו מתייאשים, איננו עוסקים בהאשמה עצמית או בהאשמת הזולת ביחס לעבר, אלא מושכים קדימה אל העתיד מתוך כיסופים גדולים עוד יותר" . הרב טאו: "המשך הבניין: אבל אנחנו מבינים שלא ביום אחד אפשר לבנות את ירושלים ואת גאולת-ישראל. לכן אבותיכם הלכו להמשיך את ההתיישבות כבר באותו לילה של הפינוי, ובבוקר כבר עלו על הקרקע בחבל חלוצה. הם לא נשברו. ודאי הם הצטערו על האובדן" . אירועי „תג מחיר" אולם יחד עם תמונה אופטימית זאת, קיימת התפתחות נוספת שאינה המשך ישיר של תלמידי הרב צבי קוק וישיבת "מרכז הרב". התפתחות אירועי האלימות והטרור המכונות „תג מחיר". כשלוש שנים לקח לציבור הציוני דתי להחלים ממשבר ההתנתקות ולתכנן תגובה נאותה כלפי אכזבתו העמוקה מהמדינה. אולם כבר בפינוי עמונה ב1 לפברואר 2006, מספר חודשים לאחר ההתנתקות, חלה תפנית חדה ביחס לקדושת החלטות המדינה. כשצעירי הציבור הציוני דתי פעלו בכל כוחם כדי למנוע את פינוי ההתנחלות עמונה. פינוי שהתבצע באלימות כוחות הביטחון. זאת בניגוד בוטה למאבק נגד ההתנתקות שהיה לרוב, נקי מאלימות . פעולות „תג מחיר" התחילו במהלך 2008 בעקבות פינוי מבנים במאחז יצהר. בכתבה שסיקרה את האירוע נכתב כי השיטה היא: "לגבות „תג מחיר" גבוה על כל פעולה מסוג זה של הצבא או המשטרה". בפעולה הראשונה זו של „תג מחיר": "נחסמו לתנועה צומת שילה, צומת הטי, צומת רחלים, חווארה, צומת חטיבת שומרון ועוד. ביצהר יודעים לספר שצה"ל הודיע שאין ביכולתו לשלוח כוחות לכל המקומות על מנת לעצור את המחאה, כך שהשיטה הוכיחה את עצמה. במקום התפתחו עימותים קשים בין יהודים לערבים, ושטחים גדולים של מרעה וזיתים נשרפו. גם בעסירה אל קבלייה התפתח עימות גדול ובמהלכו נשרף בית, תוך כדי שהצבא מודיע בקשר ש"אין לו כוחות לשלוח למקום." אירועים אלו ניתנים לבחינה הן כתוצאה ישירה של תוכנית ההתנתקות והן כתופעה בפני עצמה: • „תג מחיר" השפעתה של תוכנית ההתנתקות על הציונות הדתית: הפעילים בפעולות אלו שייכים לציבור הציוני דתי ולאותם משפחות אשר גורשו מחבל גוש קטיף, ואשר חוו את המשבר באופן אישי ולא רק באופן פוליטי ואמוני. מכאן לקשר האפשרי שאירועי „תג מחיר" הינם בעצם, תוצר ישיר של המשבר האמוני שחווה ציבור זה כתוצאה מההתנתקות מרצועת עזה. והם, הפעילים מביעים בצורה זו את חוסר האמון שלהם כלפי המדינה, כמו גם את יכולתה לקחת אחריות על עתידם. בדרך זו הם מביעים גם את האכזבה שחשו כלפי רבני הציונות הדתית הממלכתיים. שלדעתם, יישרו קו עם החלטת המדינה ואין הם עוד מוחים כלפיה - כפי שנקטו בתקופת ההתנתקות. חוסר האותנטיות של הרבנים, כפי שכתבתי על כך בפרק הסיכום בעבודה. כחיזוק לכך ראו במאמרה של ענת רוט: "הציונות הדתית במבחן הממלכתיות - מכפר מימון לעמונה". בו היא מתארת את השינוי שחל בקרב הציבור הציוני דתי שתמך במדינה. ציבור אשר נמנע מאלימות מתוך אידיאולוגיה, ואת התעוררותו למציאות ביום שאחרי. התעוררות שהביאה לאלימות כפי שנחזתה. "משהוכח כביכול שניתן לנצח את המתנחלים ולפנות יישובים בנקל, במהירות ובלא אלימות, יגבר תאבונם של אלה ותיסלל הדרך להתנתקות הבאה". , • אירועי „תג מחיר" - כתוצאה מהתפתחות רדיקליזם פוליטי בישראל: אירועי „תג מחיר" יתכן והיו יכולים להתפתח ללא קשר להתנתקות מרצועת עזה. כפי שנראה במאמרו של דון יחיא אליעזר משנת 2003 . במאמרו, הוא ציין שההתנגדות למדינה היהודית החילונית, היא בעצם "הדיסוננס הקוגניטיבי" שהציבור הציוני דתי מנסה ליישב בתוכו. אולם ללא הצלחה רבה. הוא מפרט כיצד מערך הישיבות הלאומיות תרם רבות לתהליך הרדיקליזציה הפוליטית של הציבור הציוני דתי וזאת לפני שדובר על תוכנית ההתנתקות או פינוי מאחזים: "בגישת ההרחבה הפונדמנטליסטית בנוסח הרב קוק היה טמון מלכתחילה הפוטנציאל של רדיקליזם לאומי - פוליטי, שכן הרחבת תחומה של הקדושה הדתית בגישה זו והחלתה (של הקדושה,) על ערכי הלאומיות המודרנית עשויות להביא למאבק בלתי מתפשר למען המטרות הלאומיות, הנתפסות כחלק בלתי נפרד מן המכלול המקודש של עולם הערכים הדתי". בדבריו אלה של דון יחיא הוא תיאר את הרדיקליות המתבקשת במצב בו עלולה להתרחש התנגשות בין עולם הערכים הלאומי דתי לבין החלטותיה של המדינה. לפי דון יחיא, פעולות אלו - הן תוצאה של הקושי להכיל את החילוניות של מוסדות המדינה. קושי שקשה ליישבו ועל כן הוא מתפרץ בצורה של פעולות טרור. הפעילים מנסים כביכול, לפתור את הדיסוננס מתוכם, בדרך פעולות תג מחיר. דבריו נכתבו לפני ההחלטה על ההתנתקות מרצועת עזה. • „תג מחיר" - כתוצאה ממעבר בין תודעת מהגר לתודעת קולוניאליסט: דרך נוספת להסבר תופעת „תג מחיר" היא: המעבר קטגורי ממצב של תודעת מהגר לתודעת קולוניאליסט. בנובמבר 1995, רצח יגאל אמיר את ראש הממשלה דאז יצחק רבין. הציבור הציוני דתי כולו הפך ברחוב כמו גם בתקשורת, לנרדף והואשם ברצח זה . המאבק הלא אלים בתוכנית ההתנתקות, היתה הזדמנות להראות לציבור החילוני ולמעצבי דעת הקהל, כי דוקא הציבור שנחשב לרצחני ואלים ונדחק הצידה בכלימה, נמנע מאלימות לחלוטין. ההנחה היתה שאם יעברו את המבחן, הם יתקבלו לקבוצת האליטה. כלומר, ההתרחקות מאלימות היתה כלי למטרה גבוהה יותר מאשר סיכול תוכנית ההתנתקות. כמה שנים מאוחר יותר, בניהם של המשפחות שפונו מגוש קטיף ומרצועת עזה, חשים ביטחון בצדקת דרכם וקובעים סדר יום המתאים לעקרונותיהם ומעל הכל, לא מנסים למצוא חן. כלומר אצל נערי הגבעות חל תהליך של התקרבות ברמה ההתנהגותית לשבט הציוני החילוני, שניהם אינם מתנצלים ומשדרים ביטחון ויוהרה, כדמות היהודי החדש של בן גוריון. שתי קבוצות אלו: הציוני החילוני וקבוצת נוער הגבעות, שתיהן קוראות להקים יישות ציונית על האדמה שנכבשה מתושבים המקומיים. לפי ההיסטוריונים החדשים המפעל הציוני הוא מפעל קולוניאליסטי: שהמשאב העיקרי בו הוא האדמה, מעבר לכך לא היה רצון להטמע בחברה המקומית הטבעית, בדיוק כמו הקולוניות הצרפתיות והבריטיות ברחבי אפריקה, שהיו מבודדות וניזונו מכוח עבודה זול של התושבים הטבעיים, תוך כדי ניצול משאבי המקום. קבוצת המהגרים הלבנים - הבורים- שנטמעה במרחב הטבעי של דרום אפריקה והפכה לשליט על קבוצת הילידים בה, תוך דבקות בתנ"ך ובאדמה . היא נסיון להבין את העתיד האפשרי של נוער הגבעות ופעולות „תג מחיר". בחינה של קבוצה זו, יכולה גם להסביר את דבקותם של נערי הגבעות בתורתו של הרב גינזבורג. שכן הרב גינזבורג הינו מהגר על פי הגדרה, הוא נולד בארצות הברית ועלה לישראל. אולם, זה לא מנע ממנו להרגיש שייך למקום בו לא נולד, ויתרה מזו לראות במקום זה כמקום הטבעי לו ולא לאותה אוכלוסיה שנולדה במקום וניהלה את חייה במשך דורות רבים בו. כך בדומה לבורים בדרום אפריקה אשר נדדו למרכז היבשת על מנת לברוח מעימות עם הכובשים הבריטים ולבסוף החליטו לשתף עימם פעולה על מנת לקדם את עקרונותיהם, כך גם נדדו אנשי הציונות הדתית לשטחים הכבושים על מנת לחיות על פי חוקי אמונתם. משבר ההתנתקות הבהיר להם שעליהם ליטול חלק בממשל החילוני הישראלי ולהשפיע על החלטותיו. התייחסות רבני הציונות הדתית לפעולות „תג מחיר" הרב צבי ישראל טאו התגובה לפעולות „תג מחיר" נמצאה במאמרו של דר' גדי גבריהו יושב ראש הפורום "תג מאיר" בעיתון הארץ, פורום הפועל כנגד פעולות „תג מחיר": "מוכרחים לחזור ולשנן דברים שאמר הרב צבי טאו - מנהיג ישיבות הקו - על אנשי המחתרת היהודית הראשונה(המחתרת היהודית פעלה בראשית שנות השמונים ונתפסה ב27.4.1984: "יש לנו עסק עם כת משיחית, שרוצה להביא את הגאולה לעם ישראל עם נשק ביד; [...]זוהי תפיסה של לומדי קבלה שטחיים, קטנוניים, והם גורמים בזה להרס ולחורבן" (חגי סגל, "אחים יקרים") . לפי מקור זה, הרב טאו, בהנחה שנשאר נאמן לדעותיו מאז ראה בפעילי „תג מחיר", כת משיחית המעוניינת להביא גאולה לעם ישראל באמצעות אלימות, פגיעה באיסלאם או בחפים מפשע. והם אלו הפוגעים בתהליך הגאולה ומביאים לחורבנו. הרב שלמה אבינר באתר הציוני דתי "כיפה", פרסם אורי פולק את התייחסותו של הרב שלמה אבינר לפעולות „תג מחיר", תחת הכותרת "אסור לפגוע ברכוש ערבי": "הויכוח שלנו עם הערבים הוא בשאלה של מי הארץ הזאת אבל זה לא מרשה לנו להעליב אותם, לגנוב אותם, או להציק להם". הרב זלמן מלמד לאחר מספר פעולות „תג מחיר", הוא התייחס אליהן בשיעורו השבועי וענה שראשית כל, לפני שמגנים את הפעולה יש לבדוק האם המפגע הוא יהודי ואם אכן כן, אז לברר מהיכן הוא, כלומר מאיזה חוגים המפגעים מגיעים. הוא הוסיף כי, הפיגועים אינם מסייעים לציבור הציוני הדתי במטרתו, ואף "ויש סיכוי שזה מזיק" . תגובתו של הרב לא היתה נחרצת ואף ניסתה להפנות את פעולות אלה לשוליו של הציבור הציוני דתי. הרב דוב ליאור הרב ליאור והתייחסותו לפעולות „תג מחיר": לא ניתן למצוא התייחסות מדוייקת של הרב ליאור לפעולות אלו. אולם חשוב לציין שהוא נעצר בחשד להסתה מאחר ונתן את הסכמתו ואת המלצתו לספר תורת המלך המתאר את האופן ההלכתי המאפשר לפגוע בשאינם יהודים. עלייתו של הרב יצחק גינזבורג הרב גינזבורג דוגל בשני עיקרים: ארץ ישראל השלמה והמשיחיות. את רעיון "ארץ ישראל השלמה" הוא לא רואה כמטרה בפני עצמה אלא כדרך. הדרך היחידה המאפשרת ליהודי להגיע למהות. ציטוט מדבריו: "אבל מדוע צריך את כל הארץ? מי שאומר כך אינו מבין מהי באמת ארץ ישראל, "אֶרֶץ אֲשֶׁר ה' אֱלֹהֶיךָ דֹּרֵשׁ אֹתָהּ תָּמִיד עֵינֵי ה' אֱלֹהֶיךָ בָּהּ" - אשר כולה ניתנה רק לעם ישראל, ואיננו רשאים לתת לנכרים גם חלק קטן ממנה . הרב גינזבורג אינו משתייך לאידיאולוגית הציונות הדתית של תורת הרב קוק. ומתחילת דרכו הדתית, נחשב לקיצוני בדיעותיו שלא חשש להשמיען כמו גם לפרסם חוברת שבה הוא משבח מעשה אלימות קיצוני בברכת "ברוך", "ברוך הגבר" , . הקריאה בדבריו של הרב גינזבורג היא לחזרה לטבע, חזרה לרגש המקורי הטהור, אותו רגש שאימצו גם נערי הגבעות בבחירתם לעסוק בחקלאות, רעיית בעלי חיים וקרבה מיידית לאדמה. התייחסות הרב גינזבורג לפעולות „תג מחיר": "זה קרה ביצהר בחול המועד פסח. כינס הרב יצחק גינזבורג, התוועדות תחת הכותרת "בארעא דישראל בני חורין"". יהודה יפרח הוסיף: "נדמה שזו הפעם הראשונה שבה הוגה בסדר גודל של הרב יצחק גינזבורג מתייחס ישירות לתופעה הספציפית של מעשי „תג מחיר" ומכיל אותה. אז אין באמת ואקום. מאחורי האירועים שמשגעים את המדינה יש תפיסת עולם מגובשת עם כיוון ועם יעד" הרב גינזבורג רואה בפעולות אלה, חלק הכרחי בהתפתחות הנפש היהודית וחירותה משלטון זר. המשבר האמוני לפי ענברי ענברי בחן את המשבר האמוני בקרב אנשי הציונות הדתית לאחר ההתנתקות מרצועת עזה וכתב במאמרו : "תהליך ההתנתקות מהווה מקרה בחן לבדיקת התמודדותו של הציבור הציוני דתי בכללותו עם משבר האמונה, ובפרט - בדיקת התמודדותם של מורי ההלכה של ציבור זה, אלה המבקשים לעצב את דפוסי התנהלותו הדתית." הוא הדגיש עוד: "שבחינת עמדותיו של הפלג האקטיביסטי של רבני גוש אמונים, המזוהה עם אסכולת מרכז הרב, איננה יכולה לשקף את עמדותיה של תנועת ההתנחלות בכללותה" . לפי ענברי, מדובר בשתי אסכולות חשיבה שהתפצלו מהאידיאולוגיה הציונית דתית. ושאין הבדל מהותי באידיאולוגיה של הפלגים השונים בציונות הדתית, אלא בהבדלים שעל דרך הפעולה: "אף שבדיעבד כבר הצטמצמו הפערים בין שני הזרמים. מתגובות שני הצדדים נראה ששני המחנות המנוגדים שואפים במהותם לכינונה של מדינת תורה שתחליף את המדינה החילונית חסרת ייעוד הקודש, אולם הפולמוס ביניהם הוא בעיקר על דרך הפעולה הנכונה. ענברי סיים את מאמרו בשאלה, מה ניתן לחזות לעתיד, כיצד ולאן תתפתח האידיאולוגיה הציונית דתית: "עולה השאלה, לאן נוטה המערכת של הציונות הדתית וגוש אמונים, ואיזו מן המגמות אני מעריך שתגבר. לשם כך מן הראוי ראשית לומר שבחינה כנה של התנהלות ציבור גוש אמונים ערב תוכנית ההתנתקות מלמדת שרק מיעוט ממנו השתתף בהפגנות נגד התוכנית". אלא שבשנת 2012 בראיון עם תומר פרסיקו שהתפרסם באתר "לולאת האל" . שבע שנים לאחר ההתנתקות, הדגיש ענברי את הרדיקליזציה שחלה בעקבות ההתנתקות: "אני רואה את התחזקות עמדות המיעוט, ותוהה לאן פונה תנועה זו. אני רואה שתי מגמות פוטנציאליות - האחת היא שהאכזבה והכשלון יביאו להתפרצות אלימה ותקיפה." סיכום הבאתי את תגובותיהם של הרבנים להתנתקות מרצועת עזה וניתחתי אותה על פי תיאוריית הדיסוננס קוגניטיבי. אירועי תג מחיר נכללו בעבודה מסיבות שצויינו לעיל. אולם בהכרח קשר בין אירועי תג מחיר לבין הרבנים שדיעותיהם נבחנו בעבודה זו. הם אינם תומכים בפעולות אלו וכן פעולות אלו לא יצאו מבית מדרשם. ההתפתחות הנ"ל, קרי, אירועי תג מחיר משקפת את התרחקותו של הדור ההמשך מדרך רבני הציונות הדתית. בעצם העבודה מהווה מבט פנוראמי על תהליך חילופי הגברא, כלומר חילופי דיעות והחלפתם של המנהיגים, תהליך שנעשה מתוך השטח. מכאן שאפשר להניח כי תם תפקידם של הרבנים הללו אשר היו תלמידיו של הרב צבי יהודה קוק. תם עידן הברית בין מדינת ישראל החילונית לבין הציבור הציוני הדתי. יתכן כי אנחנו כעת חווים עידן בו למנהיגים החדשים של הציונות הדתית כמו גם לציבור הצעיר יש דרישות שכבר לא ניתן להדחיק למען המטרה הגדולה (הקמת מדינת ישראל), כפי שהיה בעבר. היום הדור הצעיר דורש את מקומו בהנהגה של המדינה ובעיצוב עתידה הקרוב והרחוק. והנה דבריו של מנהיג מפלגת "בית היהודי" נפתלי בנט בכנס לציון העשור להתנתקות אמר כך: "מטרת הניתוח - מות ההתיישבות ושבירת רוח הימין. מטרת ההתנתקות היתה עצירת עליית אליטות שבמשך שנים צברו השפעה לגיטימית אבל מסוכנת לדעת אנשי השמאל. הם הרגישו שמישהו שינה את החוקים ולא טרח לספר להם". לטענתו, ההתנתקות היתה הדרך למנוע את ייהוד החברה הישראלית, כמו גם מאבק בין אליטות ישנות לחדשות. נפתלי בנט הטיב להציג את הדברים נכונה, אכן לא מדובר בחילוקי דיעות על עניין החזרת שטחים או שלום עם הפלסטינים אלא מדובר על מהותה של המדינה ולאן מועדות פניה. התחזקותו של המחנה הציוני דתי בראשות נפתלי בנט מראה כי אכן הוא צדק. אולם, השאלה הרלונטית למחקרי זה היתה, האם רדיקליזציה זו, היא צעד נוסף שתחילתו היא בשורשיו של גוש אמונים או שהרדיקליזציה נבעה מהמשבר האמוני שחל בעקבות ההתנתקות. על התגברות האלימות מעיר ענברי, כי מאחר ואין גינוי מצד המנהיגים של הציונות הדתית, לא באופן נחרץ, אזי נראה כי היא תגבר. "במצב שבו אין גינוי לאלימות מצד האוטוריטות המרכזיות , במצב שבו היריב הפוליטי מתואר באופן דמנולוגי (ערב רב, קליפה וכו') ובמצב שבו אידיאולוגיה המצדיקה אלימות ספונטנית תופסת תאוצה בקרב חוגים רדיקלים, אין להתפלא שהאלימות הופכת לחלק בלתי נפרד ממפעל ההתנחלויות. " מה היתה המטרה העיקרית במניעת האלימות במהלך ההתנתקות? במאמרה של ענת רוט התקבל הרושם כי היה חשוב לציבור הציוני דתי להיות חלק מהתרבות הדמוקרטית ולהתרחק מהשם הרע שיצא לציונות הדתית שלאחר רצח רבין: "המתנחלים" חזרו וטענו כי למרות שהם רואים בהתנתקות מהלך "אנטי ציוני, לא מוסרי ולא דמוקרטי", הם מחויבים לכללי הדמוקרטיה ואינם מתכוונים להתנגד לו באלימות" . נראה כי הטיעונים האלו, של ענברי מצד אחד ושל רוט מצד שני, הם שחקנים במפה הכללית של המהפך שחל בציונות הדתית והתקדמותה לעבר עמדות שלטוניות בהם יבואו לידי ביטוי תפישותיה האמוניות והמדיניות. שורות אלו נכתבות ערב הבחירות לכנסת העשרים ואחת והן יהוו ראיה לחלק מההנחות שהונחו בסיכום זה.},
  language  = {mul}
}
@phdthesis{Kirschbaum2020,
  author    = {Kirschbaum, Martin},
  title     = {Die {\"O}konomie der Konventionen und der Aufbau Ost},
  doi       = {10.25932/publishup-47562},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-475629},
  school      = {Universit{\"a}t Potsdam},
  pages     = {479},
  year      = {2020},
  abstract  = {Ein wesentlicher Grund f{\"u}r den fortdauernden wirtschaftlichen R{\"u}ckstand Ostdeutschlands, im Vergleich zu Westdeutschland, liegt am geringeren Gewicht technologieintensiver Branchen und, damit zusammenh{\"a}ngend, an fehlenden regionalen Wachstumszentren („Clustern"). Die {\´E}conomie des conventions (EC), ein wirtschaftswissenschaftliches und wirtschaftssoziologisches Paradigma, das in Frankreich in den 80er Jahren entstanden ist, erm{\"o}glicht die Analyse von Unternehmen und M{\"a}rkten und wurde f{\"u}r die vorliegende Dissertation verwendet, um unterschiedliche „Qualit{\"a}tskonventionen" in einer vergleichenden Analyse in der west- und ostdeutschen Maschinenbaubranche zu identifizieren. Anhand von Studien des Instituts f{\"u}r Wirtschaftsforschung in Halle (IWH), der Baden-W{\"u}rttembergischen Landesregierung und des Verbandes des Deutschen Maschinen- und Anlagenbaus e. V. (VDMA) wurde das Feld auf f{\"u}nf ostdeutsche und acht baden-w{\"u}rttembergische Raumordungsregionen eingegrenzt und ein qualitativer Stichprobenplan entwickelt. Empirisch wurden 21 leitfadengest{\"u}tzte Experteninterviews mit Gesch{\"a}ftsf{\"u}hrern der Maschinen- und Anlagenbaubranche durchgef{\"u}hrt, die mit der Qualitativen Inhaltsanalyse methodisch ausgewertet und dann mit Bezug zur EC zu Idealtypen verdichtet wurden. Im Ost-West-Vergleich zeigte sich, dass f{\"u}r ostdeutsche Unternehmen eine Entwicklung hin zum Systemanbieter, die Projekte koordinieren (Netzwerkkonvention), um damit auf (internationalen) M{\"a}rkten h{\"o}here Preise durchzusetzen (Marktkonvention), am vielversprechendsten ist. Damit einher geht der Aufbau und die Aufrechterhaltung von Netzwerken (Netzwerkkonvention), die Herausforderung besteht aber darin, auch mit Wettbewerbern (Marktkonvention) vertrauensvoll zusammen zu arbeiten. Des Weiteren zeigte sich, dass bei {\"o}ffentlich gef{\"o}rderten Verbundprojekten („Clusterpolitik") die Marktkonvention ebenfalls nicht dominant sein darf bzw. sie zumindest Kompromisse mit anderen Konventionen eingehen muss, damit diese Netzwerke nicht nach Ende der F{\"o}rderperiode auseinander fallen. Diese Befunde decken sich mit Arbeiten aus der Wirtschaftsgeographie und verwandter F{\"a}cher, bei denen gezeigt wurde, dass erst ein Gebilde aus spezifischen regionale Institutionen technologisches Lernen erm{\"o}glicht bzw. dass insbesondere die gleichzeitige Auspr{\"a}gung von Konkurrenz- und Kooperationsprinzipien („Coopetition") auf der gleichen Wertsch{\"o}pfungsstufe, es Unternehmen erm{\"o}glicht, neue wettbewerbsf{\"a}hige Produkte auf den Markt zu bringen. Eine theoretisch fundierte Clusterpolitik sollte daher nicht nur Vernetzungsaktivit{\"a}ten (Netzwerkkonvention), sondern auch den Wettbewerb (Marktkonvention) im Cluster mit f{\"o}rdern. Im Fazit wurden dann die Instrumente, die in der Literatur genannt werden, um vorhandene Clusterstrukturen weiter zu entwickeln, mit der rekonstruierten Typologie der Qualit{\"a}tskonventionen verkn{\"u}pft.},
  language  = {de}
}
@phdthesis{Knauf2020,
  author    = {Knauf, Jan},
  title     = {Synthesis of highly fluorinated precursors and their deposition conditions for self-assembled monolayers with defined small-scale surface structures as templates for the manipulation of wetting behavior},
  doi       = {10.25932/publishup-47380},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473804},
  school      = {Universit{\"a}t Potsdam},
  pages     = {X, 204},
  year      = {2020},
  abstract  = {"How Wenzel and Cassie were wrong" - this was the eye-catching title of an article published by Lichao Gao and Thomas McCarthy in 2007, in which fundamental interpretations of wetting behavior were put into question. The authors initiated a discussion on a subject, which had been generally accepted a long time ago and they showed that wetting phenomena were not as fully understood as imagined. Similarly, this thesis tries to put a focus on certain aspects of liquid wetting, which so far have been widely neglected in terms of interpretation and experimental proof. While the effect of surface roughness on the macroscopically observed wetting behavior is commonly and reliably interpreted according to the well-known models of Wenzel and Cassie/Baxter, the size-scale of the structures responsible for the surface's rough texture has not been of further interest. Analogously, the limits of these models have not been described and exploited. Thus, the question arises, what will happen when the size of surface structures is reduced to the size of the contacting liquid molecules itself? Are common methods still valid or can deviations from macroscopic behavior be observed? This thesis wants to create a starting point regarding these questions. In order to investigate the effect of smallest-scale surface structures on liquid wetting, a suitable model system is developed by means of self-assembled monolayer (SAM) formation from (fluoro)organic thiols of differing lengths of the alkyl chain. Surface topographies are created which rely on size differences of several {\AA}ngstr{\"o}ms and exhibit surprising wetting behavior depending on the choice of the individual precursor system. Thus, contact angles are experimentally detected, which deviate considerably from theoretical calculations based on Wenzel and Cassie/Baxter models and confirm that sub-nm surface topographies affect wetting. Moreover, experimentally determined wetting properties are found to correlate well to an assumed scale-dependent surface tension of the contacting liquid. This behavior has already been described for scattering experiments taking into account capillary waves on the liquid surface induced by temperature and had been predicted earlier by theoretical calculations. However, the investigation of model surfaces requires the provision of suitable precursor molecules, which are not commercially available and opens up a door to the exotic chemistry of fluoro-organic materials. During the course of this work, the synthesis of long-chain precursors is examined with a particular focus put on oligomerically pure semi-fluorinated n-alkyl thiols and n-alkyl trichlorosilanes. For this, general protocols for the syntheses of the desired compounds are developed and product mixtures are assayed to be separated into fractions of individual chain lengths by fluorous-phase high-performance liquid chromatography (F-HPLC). The transition from model systems to technically more relevant surfaces and applications is initiated through the deposition of SAMs from long-chain fluorinated n-alkyl trichlorosilanes. Depositions are accomplished by a vapor-phase deposition process conducted on a pilot-scale set-up, which enables the exact control of relevant process parameters. Thus, the influence of varying deposition conditions on the properties of the final coating is examined and analyzed for the most important parameters. The strongest effect is observed for the partial pressure of reactive water vapor, which directly controls the extent of precursor hydrolysis during the deposition process. Experimental results propose that the formation of ordered monolayers rely on the amount of hydrolyzed silanol species present in the deposition system irrespective of the exact grade of hydrolysis. However, at increased amounts of species which are able to form cross-linked molecules due to condensation reactions, films deteriorate in quality. This effect is assumed to be caused by the introduction of defects within the film and the adsorption of cross linked agglomerates. Deposition conditions are also investigated for chain extended precursor species and reveal distinct differences caused by chain elongation.},
  language  = {en}
}
@phdthesis{Knigge2020,
  author    = {Knigge, Xenia},
  title     = {Einzelmolek{\"u}l-Manipulation mittels Nano-Elektroden und Dielektrophorese},
  doi       = {10.25932/publishup-44313},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-443137},
  school      = {Universit{\"a}t Potsdam},
  pages     = {106, xxxii},
  year      = {2020},
  abstract  = {In dieser Arbeit wurden Nano-Elektroden-Arrays zur Einzel-Objekt-Immobilisierung mittels Dielektrophorese verwendet. Hierbei wurden fluoreszenzmarkierte Nano-Sph{\"a}ren als Modellsystem untersucht und die gewonnenen Ergebnisse auf biologische Proben {\"u}bertragen. Die Untersuchungen in Kombination mit verschiedenen Elektrodenlayouts f{\"u}hrten zu einer deterministischen Vereinzelung der Nano-Sph{\"a}ren ab einem festen Gr{\"o}ßenverh{\"a}ltnis zwischen Nano-Sph{\"a}re und Durchmesser der Elektrodenspitzen. An den Proteinen BSA und R-PE konnte eine dielektrophoretische Immobilisierung ebenfalls demonstriert und R-PE Molek{\"u}le zur Vereinzelung gebracht werden. Hierf{\"u}r war neben einem optimierten Elektrodenlayout, das durch Feldsimulationen den Feldgradienten betreffend gesucht wurde, eine Optimierung der Feldparameter, insbesondere von Spannung und Frequenz, erforderlich. Neben der Dielektrophorese erfolgten auch Beobachtungen anderer Effekte des elektrischen Feldes, wie z.B. Elektrolyse an Nano-Elektroden und Str{\"o}mungen {\"u}ber dem Elektroden-Array, hervorgerufen durch Joulesche W{\"a}rme und AC-elektroosmotischen Fluss. Zudem konnte Dielektrophorese an Silberpartikeln beobachtet werden und mittels Fluoreszenz-, Atom-Kraft-, Raster-Elektronen-Mikroskopie und energiedispersiver R{\"o}ntgenspektroskopie untersucht werden. Schließlich wurden die verwendeten Objektive und Kameras auf ihre Lichtempfindlichkeit hin analysiert, so dass die Vereinzelung von Biomolek{\"u}len an Nano-Elektroden nachweisbar war. Festzuhalten bleibt also, dass die Vereinzelung von Nano-Objekten und Biomolek{\"u}len an Nano-Elektroden-Arrays gelungen ist. Durch den parallelen Ansatz erlaubt dies, Aussagen {\"u}ber das Verhalten von Einzelmolek{\"u}len mit guter Statistik zu treffen.},
  language  = {de}
}
@phdthesis{Koumarelas2020,
  author    = {Koumarelas, Ioannis},
  title     = {Data preparation and domain-agnostic duplicate detection},
  doi       = {10.25932/publishup-48913},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-489131},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 97},
  year      = {2020},
  abstract  = {Successfully completing any data science project demands careful consideration across its whole process. Although the focus is often put on later phases of the process, in practice, experts spend more time in earlier phases, preparing data, to make them consistent with the systems' requirements or to improve their models' accuracies. Duplicate detection is typically applied during the data cleaning phase, which is dedicated to removing data inconsistencies and improving the overall quality and usability of data. While data cleaning involves a plethora of approaches to perform specific operations, such as schema alignment and data normalization, the task of detecting and removing duplicate records is particularly challenging. Duplicates arise when multiple records representing the same entities exist in a database. Due to numerous reasons, spanning from simple typographical errors to different schemas and formats of integrated databases. Keeping a database free of duplicates is crucial for most use-cases, as their existence causes false negatives and false positives when matching queries against it. These two data quality issues have negative implications for tasks, such as hotel booking, where users may erroneously select a wrong hotel, or parcel delivery, where a parcel can get delivered to the wrong address. Identifying the variety of possible data issues to eliminate duplicates demands sophisticated approaches. While research in duplicate detection is well-established and covers different aspects of both efficiency and effectiveness, our work in this thesis focuses on the latter. We propose novel approaches to improve data quality before duplicate detection takes place and apply the latter in datasets even when prior labeling is not available. Our experiments show that improving data quality upfront can increase duplicate classification results by up to 19\%. To this end, we propose two novel pipelines that select and apply generic as well as address-specific data preparation steps with the purpose of maximizing the success of duplicate detection. Generic data preparation, such as the removal of special characters, can be applied to any relation with alphanumeric attributes. When applied, data preparation steps are selected only for attributes where there are positive effects on pair similarities, which indirectly affect classification, or on classification directly. Our work on addresses is twofold; first, we consider more domain-specific approaches to improve the quality of values, and, second, we experiment with known and modified versions of similarity measures to select the most appropriate per address attribute, e.g., city or country. To facilitate duplicate detection in applications where gold standard annotations are not available and obtaining them is not possible or too expensive, we propose MDedup. MDedup is a novel, rule-based, and fully automatic duplicate detection approach that is based on matching dependencies. These dependencies can be used to detect duplicates and can be discovered using state-of-the-art algorithms efficiently and without any prior labeling. MDedup uses two pipelines to first train on datasets with known labels, learning to identify useful matching dependencies, and then be applied on unseen datasets, regardless of any existing gold standard. Finally, our work is accompanied by open source code to enable repeatability of our research results and application of our approaches to other datasets.},
  language  = {en}
}
@phdthesis{Krivenkov2020,
  author    = {Krivenkov, Maxim},
  title     = {Spin textures and electron scattering in nanopatterned monolayer graphene},
  doi       = {10.25932/publishup-48701},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-487017},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 176},
  year      = {2020},
  abstract  = {The current thesis is focused on the properties of graphene supported by metallic substrates and specifically on the behaviour of electrons in such systems. Methods of scanning tunneling microscopy, electron diffraction and photoemission spectroscopy were applied to study the structural and electronic properties of graphene. The purpose of the first part of this work is to introduce the most relevant aspects of graphene physics and the methodical background of experimental techniques used in the current thesis. The scientific part of this work starts with the extensive study by means of scanning tunneling microscopy of the nanostructures that appear in Au intercalated graphene on Ni(111). This study was aimed to explore the possible structural explanations of the Rashba-type spin splitting of ~100 meV experimentally observed in this system — much larger than predicted by theory. It was demonstrated that gold can be intercalated under graphene not only as a dense monolayer, but also in the form of well-periodic arrays of nanoclusters, a structure previously not reported. Such nanocluster arrays are able to decouple graphene from the strongly interacting Ni substrate and render it quasi-free-standing, as demonstrated by our DFT study. At the same time calculations confirm strong enhancement of the proximity-induced SOI in graphene supported by such nanoclusters in comparison to monolayer gold. This effect, attributed to the reduced graphene-Au distance in the case of clusters, provides a large Rashba-type spin splitting of ~60 meV. The obtained results not only provide a possible mechanism of SOI enhancement in this particular system, but they can be also generalized for graphene on other strongly interacting substrates intercalated by nanostructures of heavy noble d metals. Even more intriguing is the proximity of graphene to heavy sp-metals that were predicted to induce an intrinsic SOI and realize a spin Hall effect in graphene. Bismuth is the heaviest stable sp-metal and its compounds demonstrate a plethora of exciting physical phenomena. This was the motivation behind the next part of the current thesis, where structural and electronic properties of a previously unreported phase of Bi-intercalated graphene on Ir(111) were studied by means of scanning tunneling microscopy, spin- and angle-resolved photoemission spectroscopy and electron diffraction. Photoemission experiments revealed a remarkable, nearly ideal graphene band structure with strongly suppressed signatures of interaction between graphene and the Ir(111) substrate, moreover, the characteristic moir{\´e} pattern observed in graphene on Ir(111) by electron diffraction and scanning tunneling microscopy was strongly suppressed after intercalation. The whole set of experimental data evidences that Bi forms a dense intercalated layer that efficiently decouples graphene from the substrate. The interaction manifests itself only in the n-type charge doping (~0.4 eV) and a relatively small band gap at the Dirac point (~190 meV). The origin of this minor band gap is quite intriguing and in this work it was possible to exclude a wide range of mechanisms that could be responsible for it, such as induced intrinsic spin-orbit interaction, hybridization with the substrate states and corrugation of the graphene lattice. The main origin of the band gap was attributed to the A-B symmetry breaking and this conclusion found support in the careful analysis of the interference effects in photoemission that provided the band gap estimate of ~140 meV. While the previous chapters were focused on adjusting the properties of graphene by proximity to heavy metals, graphene on its own is a great object to study various physical effects at crystal surfaces. The final part of this work is devoted to a study of surface scattering resonances by means of photoemission spectroscopy, where this effect manifests itself as a distinct modulation of photoemission intensity. Though scattering resonances were widely studied in the past by means of electron diffraction, studies about their observation in photoemission experiments started to appear only recently and they are very scarce. For a comprehensive study of scattering resonances graphene was selected as a versatile model system with adjustable properties. After the theoretical and historical introduction to the topic of scattering resonances follows a detailed description of the unusual features observed in the photoemission spectra obtained in this work and finally the equivalence between these features and scattering resonances is proven. The obtained photoemission results are in a good qualitative agreement with the existing theory, as verified by our calculations in the framework of the interference model. This simple model gives a suitable explanation for the general experimental observations. The possibilities of engineering the scattering resonances were also explored. A systematic study of graphene on a wide range of substrates revealed that the energy position of the resonances is in a direct relation to the magnitude of charge transfer between graphene and the substrate. Moreover, it was demonstrated that the scattering resonances in graphene on Ir(111) can be suppressed by nanopatterning either by a superlattice of Ir nanoclusters or by atomic hydrogen. These effects were attributed to strong local variations of tork function and/or destruction of long-range order of thephene lattice. The tunability of scattering resonances can be applied for optoelectronic devices based on graphene. Moreover, the results of this study expand the general understanding of the phenomenon of scattering resonances and are applicable to many other materials besides graphene.},
  language  = {en}
}
@phdthesis{Kaergell2020,
  author    = {K{\"a}rgell, Martin},
  title     = {Layer formation from perovskite nanoparticles with tunable optical and electronic properties},
  doi       = {10.25932/publishup-47566},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-475667},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 233},
  year      = {2020},
  abstract  = {Hybrid organic-inorganic perovskites have attracted attention in recent years, caused by the incomparable increase in efficiency in energy convergence, which implies the application as an absorber material for solar cells. A disadvantage of these materials is, among others, the instability to moisture and UV-radiation. One possible solution for these problems is the reduction of the size towards the nano world. With that nanosized perovskites are showing superior stability in comparison to e.g. perovskite layers. Additionally to this the nanosize even enables stable perovskite structures, which could not be achieved otherwise at room temperature. This thesis is separated into two major parts. The separation is done by the composition and the band gap of the material and at the same time the shape and size of the nanoparticles. Here the division is made by the methylammonium lead tribromide nanoplatelets and the caesium lead triiodide nanocubes. The first part is focusing on the hybrid organic-inorganic perovskite (methylammonium lead tribromide) nanoplatelets with a band gap of 2.35 eV and their thermal behaviour. Due to the challenging character of this material, several analysis methods are used to investigate the sub nano and nanostructures under the influence of temperature. As a result, a shift of phase-transition temperatures towards higher temperatures is observed. This unusual behaviour can be explained by the ligand, which is incorporated in the perovskite outer structure and adds phase-stability into the system. The second part of this thesis is focusing on the inorganic caesium lead triiodide nanocubes with a band gap of 1.83 eV. These nanocrystals are first investigated and compared by TEM, XRD and other optical methods. Within these methods, a cuboid and orthorhombic structure are revealed instead of the in literature described cubic shape and structure. Furthermore, these cuboids are investigated towards their self-assembly on a substrate. Here a high degree in self-assembly is shown. As a next step, the ligands of the nanocuboids are exchanged against other ligands to increase the charge carrier mobility. This is further investigated by the above-mentioned methods. The last section is dealing with the enhancement of the CsPbI3 structure, by incorporating potassium in the crystal structure. The results are suggesting here an increase in stability.},
  language  = {en}
}
@phdthesis{Koehler2020,
  author    = {K{\"o}hler, Raphael},
  title     = {Towards seasonal prediction: stratosphere-troposphere coupling in the atmospheric model ICON-NWP},
  doi       = {10.25932/publishup-48723},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-487231},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 119},
  year      = {2020},
  abstract  = {Stratospheric variability is one of the main potential sources for sub-seasonal to seasonal predictability in mid-latitudes in winter. Stratospheric pathways play an important role for long-range teleconnections between tropical phenomena, such as the quasi-biennial oscillation (QBO) and El Ni{\~n}o-Southern Oscillation (ENSO), and the mid-latitudes on the one hand, and linkages between Arctic climate change and the mid-latitudes on the other hand. In order to move forward in the field of extratropical seasonal predictions, it is essential that an atmospheric model is able to realistically simulate the stratospheric circulation and variability. The numerical weather prediction (NWP) configuration of the ICOsahedral Non-hydrostatic atmosphere model ICON is currently being used by the German Meteorological Service for the regular weather forecast, and is intended to produce seasonal predictions in future. This thesis represents the first extensive evaluation of Northern Hemisphere stratospheric winter circulation in ICON-NWP by analysing a large set of seasonal ensemble experiments. An ICON control climatology simulated with a default setup is able to reproduce the basic behaviour of the stratospheric polar vortex. However, stratospheric westerlies are significantly too weak and major stratospheric warmings too frequent, especially in January. The weak stratospheric polar vortex in ICON is furthermore connected to a mean sea level pressure (MSLP) bias pattern resembling the negative phase of the Arctic Oscillation (AO). Since a good representation of the drag exerted by gravity waves is crucial for a realistic simulation of the stratosphere, three sensitivity experiments with reduced gravity wave drag are performed. Both a reduction of the non-orographic and orographic gravity wave drag respectively, lead to a strengthening of the stratospheric vortex and thus a bias reduction in winter, in particular in January. However, the effect of the non-orographic gravity wave drag on the stratosphere is stronger. A third experiment, combining a reduced orographic and non-orographic drag, exhibits the largest stratospheric bias reductions. The analysis of stratosphere-troposphere coupling based on an index of the Northern Annular Mode demonstrates that ICON realistically represents downward coupling. This coupling is intensified and more realistic in experiments with a reduced gravity wave drag, in particular with reduced non-orographic drag. Tropospheric circulation is also affected by the reduced gravity wave drag, especially in January, when the strongly improved stratospheric circulation reduces biases in the MSLP patterns. Moreover, a retuning of the subgrid-scale orography parameterisations leads to a significant error reduction in the MSLP in all months. In conclusion, the combination of these adjusted parameterisations is recommended as a current optimal setup for seasonal simulations with ICON. Additionally, this thesis discusses further possible influences on the stratospheric polar vortex, including the influence of tropical phenomena, such as QBO and ENSO, as well as the influence of a rapidly warming Arctic. ICON does not simulate the quasi-oscillatory behaviour of the QBO and favours weak easterlies in the tropical stratosphere. A comparison with a reanalysis composite of the easterly QBO phase reveals, that the shift towards the easterly QBO in ICON further weakens the stratospheric polar vortex. On the other hand, the stratospheric reaction to ENSO events in ICON is realistic. ICON and the reanalysis exhibit a weakened stratospheric vortex in warm ENSO years. Furthermore, in particular in winter, warm ENSO events favour the negative phase of the Arctic Oscillation, whereas cold events favour the positive phase. The ICON simulations also suggest a significant effect of ENSO on the Atlantic-European sector in late winter. To investigate the influence of Arctic climate change on mid-latitude circulation changes, two differing approaches with transient and fixed sea ice conditions are chosen. Neither ICON approach exhibits the mid-latitude tropospheric negative Arctic Oscillation circulation response to amplified Arctic warming, as it is discussed on the basis of observational evidence. Nevertheless, adding a new model to the current and active discussion on Arctic-midlatitude linkages, further contributes to the understanding of divergent conclusions between model and observational studies.},
  language  = {en}
}
@phdthesis{Kuecholl2020,
  author    = {K{\"u}choll, Denise},
  title     = {Kompetenzeinsch{\"a}tzungen Lehramtsstudierender in schulischen Praxisphasen},
  doi       = {10.25932/publishup-47337},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473376},
  school      = {Universit{\"a}t Potsdam},
  pages     = {188},
  year      = {2020},
  abstract  = {Die vorliegende Arbeit widmet sich subjektiven Kompetenzeinsch{\"a}tzungen Lehramtsstudierender in einem zentralen Element des Lehramtsstudiums - den schulischen Praxisphasen. Dabei stehen Selbstwirksamkeitserwartungen als bedeutender Aspekt professioneller Kompetenz sowie deren Bedeutung f{\"u}r das Beraten im schulischen Bereich und f{\"u}r den Umgang mit Beanspruchungsfolgen im Mittelpunkt der Arbeit. Im ersten Abschnitt werden Ans{\"a}tze zur Professionsforschung im Lehrberuf sowie das Modell der professionellen Kompetenz dargestellt (Baumert \& Kunter, 2011). Zudem werden individuelle Eingangsvoraussetzungen Lehramtsstudierender wie Pers{\"o}nlichkeitsmerkmale und p{\"a}dagogische Vorerfahrungen als bedeutende Determinanten f{\"u}r den Erwerb professioneller Kompetenz betrachtet (Kunter, Kleickmann, Klusmann \& Richter, 2011). Anschließend werden Lerngelegenheiten und zentrale Zielstellungen spezifiziert, die f{\"u}r schulische Praxisphasen kennzeichnend sind (K{\"o}nig \& Rothland, 2018). Dabei steht das Praxissemester als bedeutende Phase der Schulpraktischen Studien im Mittelpunkt der Betrachtung. Zudem werden spezifische Herausforderungen gekennzeichnet, die mit schulischen Praxisphasen verbunden sind sowie damit in Zusammenhang stehende Belastungen und Beanspruchungsfolgen (z.B. Keller-Schneider 2016b). Anschließend wird die empirische Befundlage zu negativen Beanspruchungsfolgen in schulischen Praxisphasen dargelegt und es wird auf essentielle Ressourcen im Umgang mit emotionaler Ersch{\"o}pfung und reduzierter Leistungsf{\"a}higkeit eingegangen (z.B. Rothland \& Klusmann, 2016). Zum einen wird die Bedeutsamkeit sozialer Unterst{\"u}tzung durch Mentoring als zentrale umgebungsbezogene Ressource spezifiziert, zum anderen werden Selbstwirksamkeitserwartungen als bedeutende personengebundene Ressource betrachtet. Danach wird auf den hochrelevanten Kompetenzaspekt Beraten eingegangen. Dabei werden spezifische F{\"a}higkeiten betrachtet, die essentiell f{\"u}r die schulische Beratungsarbeit sind sowie besondere Merkmale, Formen und Beratungsanl{\"a}sse. Zudem werden M{\"o}glichkeiten zur Erfassung von Beratungskompetenz aufgezeigt sowie damit verbundene Forschungsdesiderate. Abschließend wird der Blick auf die F{\"o}rderung von Beratungskompetenz im Lehramtsstudium gerichtet. Am Ende des Theoriekapitels werden die Forschungsfragen systematisiert, die sich aus der dargestellten Befundlage ergeben sowie damit in Verbindung stehende Forschungsdesiderate. Studie 1 widmet sich der Fragestellung inwieweit Selbstwirksamkeitserwartungen und soziale Unterst{\"u}tzung durch Mentoring bedeutend sind f{\"u}r den Umgang mit negativen Beanspruchungsfolgen von Burnout wie emotionaler Ersch{\"o}pfung und verminderter Leistungsf{\"a}higkeit. Zudem wird untersucht, inwieweit Mentoring den Effekt von Selbstwirksamkeitserwartungen auf die benannten Burnout-Dimensionen moderiert. In der l{\"a}ngsschnittlichen Studie konnte anhand der Daten von 192 Lehramtsstudierenden im Praxissemester gezeigt werden, dass hohe Selbstwirksamkeitserwartungen zu Beginn des Praxissemesters mit geringerer emotionaler Ersch{\"o}pfung als auch mit h{\"o}herer Leistungsf{\"a}higkeit zum Ende des Praxissemesters einhergehen. Zudem konnte gezeigt werden, dass der Effekt von Selbstwirksamkeitserwartungen auf Leistungsf{\"a}higkeit durch Mentoring moderiert wird. Zur Auswertung der Daten wurden multiple Regressionsanalysen berechnet. Studie 2 widmet sich der Entwicklung und Validierung einer Skala zur Erfassung der Beratungskompetenz, die bereits im Rahmen des Lehramtsstudiums eingesetzt werden kann. In Faktorenanalysen konnte mithilfe der Daten von 200 Lehramtsstudierenden gezeigt werden, dass sich Beratungskompetenz anhand von vier Subskalen beschreiben l{\"a}sst. Die Skalen wurden als Personale Ressourcen, Kooperation- und Perspektiven{\"u}bernahme, Berater-Skills sowie Ressourcen- und L{\"o}sungsorientierung bezeichnet und erwiesen sich hinsichtlich der internen Konsistenz insgesamt als akzeptabel. F{\"u}r die einzelnen Subskalen ergaben sich zudem schwache bis mittlere Zusammenh{\"a}nge mit den Validierungsvariablen Selbstwirksamkeit in Beratungen, der Beratungsmotivation sowie P{\"a}dagogische Vorerfahrungen. Studie 3 ging der Frage nach, inwieweit zentrale individuelle Eingangsvoraussetzungen von Lehramtsstudierenden wie Pers{\"o}nlichkeitsmerkmale und p{\"a}dagogische Vorerfahrungen bedeutend sind f{\"u}r Selbstwirksamkeitserwartungen in Sch{\"u}ler-Beratungen. Ebenfalls basierend auf Fragebogendaten von 200 Praxissemesterstudierenden konnte anhand multipler Regressionsanalysen gezeigt werden, dass hohe Offenheit f{\"u}r neue Erfahrungen und geringer Neurotizismus mit hohen Selbstwirksamkeitserwartungen einhergehen. Zudem stehen p{\"a}dagogische Vorerfahrungen in positivem und signifikantem Zusammenhang mit Selbstwirksamkeitserwartungen. Die Studie widmet sich abschließend insbesondere der F{\"o}rderung von Beratungskompetenz im Lehramtsstudium. In Studie 4 wird ein Seminarbaustein pr{\"a}sentiert, mithilfe dessen Beratungskompetenz im Lehramtsstudium gef{\"o}rdert werden kann. Mit dem Konzept k{\"o}nnen s{\"a}mtliche Aspekte professioneller Kompetenz im Bereich Beraten sowohl theoretisch vermittelt als auch praktisch erprobt werden. Die R{\"u}ckmeldungen von Lehramtsstudierenden, die den Seminarbaustein erprobt haben, geben erste Hinweise darauf, dass F{\"a}higkeiten im Bereich schulischer Beratungen gef{\"o}rdert werden k{\"o}nnen. Die vorliegende Arbeit wird durch die Gesamtdiskussion der Ergebnisse beendet und es werden Grenzen der Arbeit, Anschlussfragen und p{\"a}dagogischen Implikationen besprochen.},
  language  = {de}
}
@phdthesis{Latza2020,
  author    = {Latza, Victoria Maria},
  title     = {Interactions involving lipid-based surfaces},
  doi       = {10.25932/publishup-44559},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445593},
  school      = {Universit{\"a}t Potsdam},
  pages     = {217},
  year      = {2020},
  abstract  = {Interactions involving biological interfaces such as lipid-based membranes are of paramount importance for all life processes. The same also applies to artificial interfaces to which biological matter is exposed, for example the surfaces of drug delivery systems or implants. This thesis deals with the two main types of interface interactions, namely (i) interactions between a single interface and the molecular components of the surrounding aqueous medium and (ii) interactions between two interfaces. Each type is investigated with regard to an important scientific problem in the fields of biotechnology and biology: 1.) The adsorption of proteins to surfaces functionalized with hydrophilic polymer brushes; a process of great biomedical relevance in context with harmful foreign-body-response to implants and drug delivery systems. 2.) The influence of glycolipids on the interaction between lipid membranes; a hitherto largely unexplored phenomenon with potentially great biological relevance. Both problems are addressed with the help of (quasi-)planar, lipid-based model surfaces in combination with x-ray and neutron scattering techniques which yield detailed structural insights into the interaction processes. Regarding the adsorption of proteins to brush-functionalized surfaces, the first scenario considered is the exposure of the surfaces to human blood serum containing a multitude of protein species. Significant blood protein adsorption was observed despite the functionalization, which is commonly believed to act as a protein repellent. The adsorption consists of two distinct modes, namely strong adsorption to the brush grafting surface and weak adsorption to the brush itself. The second aspect investigated was the fate of the brush-functionalized surfaces when exposed to aqueous media containing immune proteins (antibodies) against the brush polymer, an emerging problem in current biomedical applications. To this end, it was found that antibody binding cannot be prevented by variation of the brush grafting density or the polymer length. This result motivates the search for alternative, strictly non-antigenic brush chemistries. With respect to the influence of glycolipids on the interaction between lipid membranes, this thesis focused on the glycolipids' ability to crosslink and thereby to tightly attract adjacent membranes. This adherence is due to preferential saccharide-saccharide interactions occurring among the glycolipid headgroups. This phenomenon had previously been described for lipids with special oligo-saccharide motifs. Here, it was investigated how common this phenomenon is among glycolipids with a variety of more abundant saccharide-headgroups. It was found that glycolipid-induced membrane crosslinking is equally observed for some of these abundant glycolipid types, strongly suggesting that this under-explored phenomenon is potentially of great biological relevance.},
  language  = {en}
}
@phdthesis{LeGallMboro2020,
  author    = {LeGall, Yann and Mboro, Mnyaka Sururu},
  title     = {Remembering the dismembered},
  doi       = {10.25932/publishup-50850},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-508502},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 346},
  year      = {2020},
  abstract  = {This thesis - written in co-authorship with Tanzanian activist Mnyaka Sururu Mboro - examines different cases of repatriation of ancestral remains to African countries and communities through the prism of postcolonial memory studies. It follows the theft and displacement of prominent ancestors from East and Southern Africa (Sarah Baartman, Dawid Stuurman, Mtwa Mkwawa, Songea Mbano, King Hintsa and the victims of the Ovaherero and Nama genocides) and argues that efforts made for the repatriation of their remains have contributed to a transnational remembrance of colonial violence. Drawing from cultural studies theories such as "multidirectional memory", "rehumanisation" and "necropolitics", the thesis argues for a new conceptualisation or "re-membrance" in repatriation, through processes of reunion, empowerment, story-telling and belonging. Besides, the afterlives of the dead ancestors, who stand at the centre of political debates on justice and reparations, remind of their past struggles against colonial oppression. They are therefore "memento vita", fostering counter-discourses that recognize them as people and stories. This manuscript is accompanied by a "(web)site of memory" where some of the research findings are made available to a wider audience. This blog also hosts important sound material which appears in the thesis as interventions by external contributors. Through QR codes, both the written and the digital version are linked with each other to problematize the idea of a written monograph and bring a polyphonic perspective to those diverse, yet connected, histories.},
  language  = {en}
}
@phdthesis{Liu2020,
  author    = {Liu, Qi},
  title     = {Influence of CO2 degassing on microbial community distribution and activity in the Hartoušov degassing system, western Eger Rift (Czech Republic)},
  doi       = {10.25932/publishup-47534},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-475341},
  school      = {Universit{\"a}t Potsdam},
  pages     = {146},
  year      = {2020},
  abstract  = {The Cheb Basin (CZ) is a shallow Neogene intracontinental basin located in the western Eger Rift. The Cheb Basin is characterized by active seismicity and diffuse degassing of mantle-derived CO2 in mofette fields. Within the Cheb Basin, the Hartoušov mofette field shows a daily CO2 flux of 23-97 tons. More than 99\% of CO2 released over an area of 0.35 km2. Seismic active periods have been observed in 2000 and 2014 in the Hartoušov mofette field. Due to the active geodynamic processes, the Cheb Basin is considered to be an ideal region for the continental deep biosphere research focussing on the interaction of biological processes with geological processes. To study the influence of CO2 degassing on microbial community in the surface and subsurface environments, two 3-m shallow drillings and a 108.5-m deep scientific drilling were conducted in 2015 and 2016 respectively. Additionally, the fluid retrieved from the deep drilling borehole was also recovered. The different ecosystems were compared regarding their geochemical properties, microbial abundances, and microbial community structures. The geochemistry of the mofette is characterized by low pH, high TOC, and sulfate contents while the subsurface environment shows a neutral pH, and various TOC and sulfate contents in different lithological settings. Striking differences in the microbial community highlight the substantial impact of elevated CO2 concentrations and high saline groundwater on microbial processes. In general, the microorganisms had low abundance in the deep subsurface sediment compared with the shallow mofette. However, within the mofette and the deep subsurface sediment, the abundance of microbes does not show a typical decrease with depth, indicating that the uprising CO2-rich groundwater has a strong influence on the microbial communities via providing sufficient substrate for anaerobic chemolithoautotrophic microorganisms. Illumina MiSeq sequencing of the 16S rRNA genes and multivariate statistics reveals that the pH strongly influences the microbial community composition in the mofette, while the subsurface microbial community is significantly influenced by the groundwater which motivated by the degassing CO2. Acidophilic microorganisms show a much higher relative abundance in the mofette. Meanwhile, the OTUs assigned to family Comamonadaceae are the dominant taxa which characterize the subsurface communities. Additionally, taxa involved in sulfur cycling characterizing the microbial communities in both mofette and CO2 dominated subsurface environments. Another investigated important geo-bio interaction is the influence of the seismic activity. During seismic events, released H2 may serve as the electron donor for microbial hydrogenotrophic processes, such as methanogenesis. To determine whether the seismic events can potentially trigger methanogenesis by the elevated geogenic H2 concentration, we performed laboratory simulation experiments with sediments retrieved from the drillings. The simulation results indicate that after the addition of hydrogen, substantial amounts of methane were produced in incubated mofette sediments and deep subsurface sediments. The methanogenic hydrogenotrophic genera Methanobacterium was highly enriched during the incubation. The modeling of the in-situ observation of the earthquake swarm period in 2000 at the Novy Kostel focal area/Czech Republic and our laboratory simulation experiments reveals a close relation between seismic activities and microbial methane production via earthquake-induced H2 release. We thus conclude that H2 - which is released during seismic activity - can potentially trigger methanogenic activity in the deep subsurface. Based on this conclusion, we further hypothesize that the hydrogenotrophic early life on Earth was boosted by the Late Heavy Bombardment induced seismic activity in approximately 4.2 to 3.8 Ga.},
  language  = {en}
}
@phdthesis{Liu2020,
  author    = {Liu, Sibiao},
  title     = {Controls of foreland-deformation patterns in the orogen-foreland shortening system},
  doi       = {10.25932/publishup-44573},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445730},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vi, 150},
  year      = {2020},
  abstract  = {The Andean Plateau (Altiplano-Puna Plateau) of the southern Central Andes is the second-highest orogenic plateau on our planet after Tibet. The Andean Plateau and its foreland exhibit a pronounced segmentation from north to south regarding the style and magnitude of deformation. In the Altiplano (northern segment), more than 300 km of tectonic shortening has been recorded, which started during the Eocene. A well-developed thin-skinned thrust wedge located at the eastern flank of the plateau (Subandes) indicates a simple-shear shortening mode. In contrast, the Puna (southern segment) records approximately half of the shortening of the Altiplano - and the shortening started later. The tectonic style in the Puna foreland switches to a thick-skinned mode, which is related to pure-shear shortening. In this study, carried out in the framework of the StRATEGy project, high-resolution 2D thermomechanical models were developed to systematically investigate controls of deformation patterns in the orogen-foreland pair. The 2D and 3D models were subsequently applied to study the evolution of foreland deformation and surface topography in the Altiplano-Puna Plateau. The models demonstrate that three principal factors control the foreland-deformation patterns: (i) strength differences in the upper lithosphere between the orogen and its foreland, rather than a strength difference in the entire lithosphere; (ii) gravitational potential energy of the orogen (GPE) controlled by crustal and lithospheric thicknesses, and (iii) the strength and thickness of foreland-basin sediments. The high-resolution 2D models are constrained by observations and successfully reproduce deformation structures and surface topography of different segments of the Altiplano-Puna plateau and its foreland. The developed 3D models confirm these results and suggest that a relatively high shortening rate in the Altiplano foreland (Subandean foreland fold-and-thrust belt) is due to simple-shear shortening facilitated by thick and mechanically weak sediments, a process which requires a much lower driving force than the pure-shear shortening deformation mode in the adjacent broken foreland of the Puna, where these thick sedimentary basin fills are absent. Lower shortening rate in the Puna foreland is likely accommodated in the forearc by the slab retreat.},
  language  = {en}
}
@phdthesis{LopezdeGuerenu2020,
  author    = {L{\´o}pez de Guere{\~n}u, Anna},
  title     = {Tm3+-doped NaYF4 nanoparticles},
  doi       = {10.25932/publishup-47559},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-475593},
  school      = {Universit{\"a}t Potsdam},
  pages     = {119},
  year      = {2020},
  abstract  = {Lately, the integration of upconverting nanoparticles (UCNP) in industrial, biomedical and scientific applications has been increasingly accelerating, owing to the exceptional photophysical properties that UCNP offer. Some of the most promising applications lie in the field of medicine and bioimaging due to such advantages as, among others, deeper tissue penetration, reduced optical background, possibility for multicolor imaging, and lower toxicity, compared to many known luminophores. However, some questions regarding not only the fundamental photophysical processes, but also the interaction of the UCNP with other luminescent reporters frequently used for bioimaging and the interaction with biological media remain unanswered. These issues were the primary motivation for the presented work. This PhD thesis investigated several aspects of various properties and possibilities for bioapplications of Yb3+,Tm3+-doped NaYF4 upconverting nanoparticles. First, the effect of Gd3+ doping on the structure and upconverting behaviour of the nanocrystals was assessed. The ageing process of the UCNP in cyclohexane was studied over 24 months on the samples with different Gd3+ doping concentrations. Structural information was gathered by means of X-ray diffraction (XRD), transmission electron microscopy (TEM), dynamic light scattering (DLS), and discussed in relation to spectroscopic results, obtained through multiparameter upconversion luminescence studies at various temperatures (from 4 K to 295 K). Time-resolved and steady-state emission spectra recorded over this ample temperature range allowed for a deeper understanding of photophysical processes and their dependence on structural changes of UCNP. A new protocol using a commercially available high boiling solvent allowed for faster and more controlled production of very small and homogeneous UCNP with better photophysical properties, and the advantages of a passivating NaYF4 shell were shown. F{\"o}rster resonance energy transfer (FRET) between four different species of NaYF4: Yb3+, Tm3+ UCNP (synthesized using the improved protocol) and a small organic dye was studied. The influence of UCNP composition and the proximity of Tm3+ ions (donors in the process of FRET) to acceptor dye molecules have been assessed. The brightest upconversion luminescence was observed in the UCNP with a protective inert shell. UCNP with Tm3+ ions only in the shell were the least bright, but showed the most efficient energy transfer. In the final part, two surface modification strategies were applied to make UCNP soluble in water, which simultaneously allowed for linking them via a non-toxic copper-free click reaction to the liposomes, which served as models for further cell experiments. The results were assessed on a confocal microscope system, which was made possible by lesser known downshifting properties of Yb3+, Tm3+-doped UCNP. Preliminary antibody-staining tests using two primary and one dye-labelled secondary antibodies were performed on MDCK-II cells.},
  language  = {en}
}
@phdthesis{Mamo2020,
  author    = {Mamo, Shai},
  title     = {משנתו ההלכתית של הרב משה כלפון הכהן מג'רבה כפי שהיא משתקפת בחיבוריו ההלכתיים ברית כהותה ושות שואל ונשאל},
  doi       = {10.25932/publishup-46956},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-469567},
  school      = {Universit{\"a}t Potsdam},
  pages     = {200},
  year      = {2020},
  abstract  = {מחקר זה מתמקד במשנתו ההלכתית של הרב כלפון, כפי שהשתקפה בחיבוריו 'שואל ונשאל' ו'ברית כהונה' שהם ספרי שו"ת (responsa) הפורשים היקף נרחב של יחסיו לתמורות שחלו באותן שנים בקהילה היהודית באי ג'רבה שליד תוניס. נבחנים יחסו למודרנה, לחינוך כללי, למעמד האשה ועוד. כמו"כ נבדקה דרכו ההלכתית, הדומיננטיות שהעניק למסורת הג'רבאית גם לעומת פסיקותיו של רבי יוסף קארו.},
  language  = {mul}
}
@phdthesis{Mandal2020,
  author    = {Mandal, Partha Sarathi},
  title     = {Controlling the surface band gap in topological states of matter},
  doi       = {10.25932/publishup-48045},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-480459},
  school      = {Universit{\"a}t Potsdam},
  pages     = {122},
  year      = {2020},
  abstract  = {In the present study, we employ the angle-resolved photoemission spectroscopy (ARPES) technique to study the electronic structure of topological states of matter. In particular, the so-called topological crystalline insulators (TCIs) Pb1-xSnxSe and Pb1-xSnxTe, and the Mn-doped Z2 topological insulators (TIs) Bi2Te3 and Bi2Se3. The Z2 class of strong topological insulators is protected by time-reversal symmetry and is characterized by an odd number of metallic Dirac type surface states in the surface Brillouin zone. The topological crystalline insulators on the other hand are protected by the individual crystal symmetries and exhibit an even number of Dirac cones. The topological properties of the lead tin chalcogenides topological crystalline insulators can be tuned by temperature and composition. Here, we demonstrate that Bi-doping of the Pb1-xSnxSe(111) epilayers induces a quantum phase transition from a topological crystalline insulator to a Z2 topological insulator. This occurs because Bi-doping lifts the fourfold valley degeneracy in the bulk. As a consequence a gap appears at ⌈¯, while the three Dirac cones at the M̅ points of the surface Brillouin zone remain intact. We interpret this new phase transition is caused by lattice distortion. Our findings extend the topological phase diagram enormously and make strong topological insulators switchable by distortions or electric field. In contrast, the bulk Bi doping of epitaxial Pb1-xSnxTe(111) films induces a giant Rashba splitting at the surface that can be tuned by the doping level. Tight binding calculations identify their origin as Fermi level pinning by trap states at the surface. Magnetically doped topological insulators enable the quantum anomalous Hall effect (QAHE) which provide quantized edge states for lossless charge transport applications. The edge states are hosted by a magnetic energy gap at the Dirac point which has not been experimentally observed to date. Our low temperature ARPES studies unambiguously reveal the magnetic gap of Mn-doped Bi2Te3. Our analysis shows a five times larger gap size below the Tc than theoretically predicted. We assign this enhancement to a remarkable structure modification induced by Mn doping. Instead of a disordered impurity system, a self-organized alternating sequence of MnBi2Te4 septuple and Bi2Te3quintuple layers is formed. This enhances the wave-function overlap and gives rise to a large magnetic gap. Mn-doped Bi2Se3 forms similar heterostructure, but only a nonmagnetic gap is observed in this system. This correlates with the difference in magnetic anisotropy due to the much larger spin-orbit interaction in Bi2Te3 compared to Bi2Se3. These findings provide crucial insights for pushing lossless transport in topological insulators towards room-temperature applications.},
  language  = {en}
}
@phdthesis{Mardoukhi2020,
  author    = {Mardoukhi, Yousof},
  title     = {Random environments and the percolation model},
  doi       = {10.25932/publishup-47276},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-472762},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxii, 103},
  year      = {2020},
  abstract  = {Percolation process, which is intrinsically a phase transition process near the critical point, is ubiquitous in nature. Many of its applications embrace a wide spectrum of natural phenomena ranging from the forest fires, spread of contagious diseases, social behaviour dynamics to mathematical finance, formation of bedrocks and biological systems. The topology generated by the percolation process near the critical point is a random (stochastic) fractal. It is fundamental to the percolation theory that near the critical point, a unique infinite fractal structure, namely the infinite cluster, would emerge. As de Gennes suggested, the properties of the infinite cluster could be deduced by studying the dynamical behaviour of the random walk process taking place on it. He coined the term the ant in the labyrinth. The random walk process on such an infinite fractal cluster exhibits a subdiffusive dynamics in the sense that the mean squared displacement grows as ~t2/dw, where dw, called the fractal dimension of the random walk path, is greater than 2. Thus, the random walk process on the infinite cluster is classified as a process exhibiting the properties of anomalous diffusions. Yet near the critical point, the infinite cluster is not the sole emergent topology, but it coexists with other clusters whose size is finite. Though finite, on specific length scales these finite clusters exhibit fractal properties as well. In this work, it is assumed that the random walk process could take place on these finite size objects as well. Bearing this assumption in mind requires one address the non-equilibrium initial condition. Due to the lack of knowledge on the propagator of the random walk process in stochastic random environments, a phenomenological correspondence between the renowned Ornstein-Uhlenbeck process and the random walk process on finite size clusters is established. It is elucidated that when an ensemble of these finite size clusters and the infinite cluster is considered, the anisotropy and size of these finite clusters effects the mean squared displacement and its time averaged counterpart to grow in time as ~t(d+df (t-2))/dw, where d is the embedding Euclidean dimension, df is the fractal dimension of the infinite cluster, and , called the Fisher exponent, is a critical exponent governing the power-law distribution of the finite size clusters. Moreover, it is demonstrated that, even though the random walk process on a specific finite size cluster is ergodic, it exhibits a persistent non-ergodic behaviour when an ensemble of finite size and the infinite clusters is considered.},
  language  = {en}
}
@phdthesis{Markushyna2020,
  author    = {Markushyna, Yevheniia},
  title     = {Modern photoredox transformations applied to the needs of organic synthesis},
  doi       = {10.25932/publishup-47766},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-477661},
  school      = {Universit{\"a}t Potsdam},
  pages     = {275},
  year      = {2020},
  abstract  = {Abstract. Catalysis is one of the most effective tools for the highly efficient assembly of complex molecular structures. Nevertheless, it is mainly represented by transition metal-based catalysts and typically is an energy consuming process. Therefore, photocatalysis utilizing solar energy is one of the appealing approaches to overcome these problems. A great alternative to classic transition metal-based photocatalysts, carbon nitrides, a group of organic polymeric semiconductors, have already shown their efficiency in water splitting, CO2 reduction, and organic pollutants degradation. However, these materials have also a great potential for the use in functionalization of complex organic molecules for synthetic needs as it was shown in recent years. This work addresses the challenge to develop efficient system for heterogeneous organic photocatalysis, employing cheap and environmentally benign photocatalysts - carbon nitrides. Herein, fundamental properties of semiconductors are studied from the organic chemistry standpoint; the inherent properties of carbon nitrides, such as ability to accumulate electrons, are deeply investigated and their effect on the reaction outcome is established. Thus, understanding of the electron charging processes allowed for the synthesis of otherwise hardly-achieved diazetidines-1,3 by tetramerization of benzylamines. Furthermore, the high electron capacity of Potassium Poly(heptazine imide)s (K-PHI) made possible a multi-electron reduction of aromatic nitro compounds to bare or formylated anilines. Additionally, two deep eutectic solvents (DES) were designed as a sustainable reaction media and reducing reagent for this reaction. Eventually, the high oxidation ability of carbon nitride K-PHI is employed in a challenging reaction of halide anion oxidation (Cl―, Br―) to accomplish electrophilic substitution in aromatic ring. The possibility to utilize NaCl solution (seawater mimetic) for the chlorination of electron rich arenes was shown. Eventually, light itself is used as a tool in a chromoselective photocatalytic oxidation of aromatic thiols and thioacetatas to three different compounds, using UV, blue, and red LEDs. All in all, the work enhances understanding the mechanism of heterogeneous photocatalysis in synthetic organic reactions and therefore, is a step forward to the sustainable methods of synthesis in organic chemistry.},
  language  = {en}
}
@phdthesis{Massolt2020,
  author    = {Massolt, Joost Willem},
  title     = {Perceived relevance of physics problems},
  doi       = {10.25932/publishup-47292},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-472925},
  school      = {Universit{\"a}t Potsdam},
  pages     = {102},
  year      = {2020},
  abstract  = {Pre-service physics teachers often have difficulties seeing the relevance of the content of the content knowledge courses they attend in their study; they regularly do not see the connection with the physics they need in their later profession as a secondary school teacher. A lower perceived relevance is however connected to motivational problems which leads to both a qualitative and quantitative problem: not only is there a relation between the drop-out of students and their motivation, but their level of conceptual understanding is also suffering under this lower motivation. In order to increase the perceived relevance of the problems that pre-service physics teachers have to solve for the courses Experimentalphysik 1 and 2, an intervention study has been designed and implemented. In these content knowledge courses, first- and second semester students attend lectures, do experiments and they solve problems on weekly problem sets which are discussed in tutorial sessions. The problems on a typical problem set are however mainly quantitative problems that have no connection to school. In the intervention study, regular, quantitative problems are used next to two newly designed conceptual (qualitative) problem types. One of these problem types are conceptual problems that have no implicit or explicit school-relevance; the other problems are based on school-related content knowledge. This content knowledge category describes knowledge that leads to a deeper understanding of school knowledge, relevant for teachers: a teacher-specific content knowledge. A new model for this category, SRCK, has been conceptualised and operationalised as a cross-disciplinary model that consists of conceptual knowledge and skills necessary for this deeper understanding of content that is relevant to teaching at a secondary school. During two semesters in both the courses Experimentalphysik 1 and 2 (N = 75 and N = 43 respectively) students had to solve the problems on the problem sets. At the start of every tutorial session, they were asked to rate all the problems with respect to perceived relevance and difficulty. Analyses show that the problems based on SRCK were perceived as more relevant than the regular, quantitative problems. However, this difference is only statistically significant for the course Experimentalphysik 2. The SRCK-problems show the connection between the content of the problems and school physics and are therefore seen as more relevant. In Experimentalphysik 1, the content is not that distant to school physics. This might be the reason that the students see all the problem types as just as relevant to them. When we however only look at the final third of the first semester, where more advanced subjects - that are not necessarily discussed in secondary school physics - are discussed, we see that in this part the SRCK-problems are seen as more relevant than the regular problems too. We can therefore conclude that if the content is distant to school physics, the SRCK-problems are seen as more relevant than the regular problems. We do not see a statistically significant difference between the (conceptual) problems based on SRCK and the conceptual problems that are not based on SRCK (and therefore have no school relevance). This means that we do not know whether the conceptual problems based on SRCK are more relevant because they are based on SRCK or because they are conceptual. In order to find out what problem properties have an influence on the perceived relevance of these problems by pre-service teachers, an interview study with N = 7 pre-service teachers was conducted. This interview was done using the repertory grid technique, based on the personal construct theory by Kelly (1955). This technique makes it possible to find personal constructs of students: how do students determine for themselves how relevant a problem is to them? It allows to capture their intuition or gut feeling. These personal constructs could then give us information about the problem properties that have a positive influence on relevance. Six categories of personal constructs were found that have a high similarity to relevance. According to the personal constructs that were generated in the interviews, physics problems are more relevant when they are more conceptual (compared to calculational), are close to everyday life, have a lower level of mathematical requirement, have a content that is more school-relevant, give the students the idea that they have learned something, and contain a situation that has to be analysed. Of the six problem properties described above, one can be connected to the facets of SRCK: many problems based on SRCK contain a situation (e.g. a textbook with a simplified explanation, a student solution with an error) that has to be analysed. The expectation is that problems that are based on the six properties described above would be perceived as more relevant to pre-service physics teachers.},
  language  = {en}
}
@phdthesis{Meijer2020,
  author    = {Meijer, Niels},
  title     = {Asian dust, monsoons and westerlies during the Eocene},
  doi       = {10.25932/publishup-48868},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-488687},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 155},
  year      = {2020},
  abstract  = {The East Asian monsoons characterize the modern-day Asian climate, yet their geological history and driving mechanisms remain controversial. The southeasterly summer monsoon provides moisture, whereas the northwesterly winter monsoon sweeps up dust from the arid Asian interior to form the Chinese Loess Plateau. The onset of this loess accumulation, and therefore of the monsoons, was thought to be 8 million years ago (Ma). However, in recent years these loess records have been extended further back in time to the Eocene (56-34 Ma), a period characterized by significant changes in both the regional geography and global climate. Yet the extent to which these reconfigurations drive atmospheric circulation and whether the loess-like deposits are monsoonal remains debated. In this thesis, I study the terrestrial deposits of the Xining Basin previously identified as Eocene loess, to derive the paleoenvironmental evolution of the region and identify the geological processes that have shaped the Asian climate. I review dust deposits in the geological record and conclude that these are commonly represented by a mix of both windblown and water-laid sediments, in contrast to the pure windblown material known as loess. Yet by using a combination of quartz surface morphologies, provenance characteristics and distinguishing grain-size distributions, windblown dust can be identified and quantified in a variety of settings. This has important implications for tracking aridification and dust-fluxes throughout the geological record. Past reversals of Earth's magnetic field are recorded in the deposits of the Xining Basin and I use these together with a dated volcanic ash layer to accurately constrain the age to the Eocene period. A combination of pollen assemblages, low dust abundances and other geochemical data indicates that the early Eocene was relatively humid suggesting an intensified summer monsoon due to the warmer greenhouse climate at this time. A subsequent shift from predominantly freshwater to salt lakes reflects a long-term aridification trend possibly driven by global cooling and the continuous uplift of the Tibetan Plateau. Superimposed on this aridification are wetter intervals reflected in more abundant lake deposits which correlate with highstands of the inland proto-Paratethys Sea. This sea covered the Eurasian continent and thereby provided additional moisture to the winter-time westerlies during the middle to late Eocene. The long-term aridification culminated in an abrupt shift at 40 Ma reflected by the onset of windblown dust, an increase in steppe-desert pollen, the occurrence of high-latitude orbital cycles and northwesterly winds identified in deflated salt deposits. Together, these indicate the onset of a Siberian high atmospheric pressure system driving the East Asian winter monsoon as well as dust storms and was triggered by a major sea retreat from the Asian interior. These results therefore show that the proto-Paratethys Sea, though less well recognized than the Tibetan Plateau and global climate, has been a major driver in setting up the modern-day climate in Asia.},
  language  = {en}
}
@phdthesis{Menting2020,
  author    = {Menting, Thijs},
  title     = {Purposiveness of nature in Kant's third critique},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-484-5},
  doi       = {10.25932/publishup-44433},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-444336},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xii, 304},
  year      = {2020},
  abstract  = {This dissertation aims to deliver a transcendental interpretation of Immanuel Kant's Kritik der Urteilskraft, considering both its coherence with other critical works as well as the internal coherence of the work itself. This interpretation is called transcendental insofar as special emphasis is placed on the newly introduced cognitive power, namely the reflective power of judgement, guided by the a priori principle of purposiveness. In this way the seeming manifold of themes, varying from judgements of taste through culture to teleological judgements about natural purposes, are discussed exclusively in regard of their dependence on this faculty and its transcendental principle. In contrast, in contemporary scholarship the book is often treated as a fragmented work, consisting of different independent parts, while my focus lies on the continuity comprised primarily of the activity of the power of judgement. Going back to certain central yet silently presupposed concepts, adopted from previous critical works, the main contribution of this study is to integrate the KU within the overarching critical project. More specifically, I have argue how the need for the presupposition by the reflective power of judgement follows from the peculiar character of our sense-dependent discursive mind. Because we are sense-dependent discursive minds, we do not and cannot have immediate insight into all of nature's features. The particular constitution of our mind rather demands conceptually informed representations which mediately refer to objects. Having said that, the principle of purposiveness, namely the presupposition that nature is organized in concert with the particular constitution of our mind, is a necessary condition for the possibility of reflection on nature's empirical features. Reflection refers on my account to a process of selecting features in order to allow a classification, including reflection on the method, means and selection criteria. Rather than directly contributing to cognition, like the categories, reflective judgements thus express our ignorance when it comes to the motivation behind nature's design, and this is most forcefully expressed by judgements of taste and teleological judgements about organized matter. In this way, reflection, regardless whether it is manifested in concept acquisition, scientific systematization, judgements of taste or judgements about organized matter, relies on a principle of the power of judgement which is revealed and justified in this transcendental inquiry.},
  language  = {en}
}
@phdthesis{Milewski2020,
  author    = {Milewski, Robert},
  title     = {Potential of optical remote sensing for the analysis of salt pan environments},
  doi       = {10.25932/publishup-47373},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473732},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xii, 145},
  year      = {2020},
  abstract  = {Salt pans also termed playas are common landscape features of hydrologically closed basins in arid and semiarid zones, where evaporation significantly exceeds the local precipitation. The analysis and monitoring of salt pan environments is important for the evaluation of current and future impact of these landscape features. Locally, salt pans have importance for the ecosystem, wildlife and human health, and through dust emissions they influence the climate on regional and global scales. Increasing economic exploitation of these environments in the last years, e.g. by brine extraction for raw materials, as well as climate change severely affect the water, material and energy balance of these systems. Optical remote sensing has the potential to characterise salt pan environments and to increase the understanding of processes in playa basins, as well as to assess wider impacts and feedbacks that exist between climate forcing and human intervention in their regions. Remote sensing techniques can provide information for extensive regions on a high temporal basis compared to traditional field samples and ground observations. Specifically, for salt pans that are often challenging to study because of their large size, remote location, and limited accessibility due to missing infrastructure and ephemeral flooding. Furthermore, the availability of current and upcoming hyperspectral remote sensing data opened the opportunity for the analyses of the complex reflectance signatures that relate to the mineralogical mixtures found in the salt pan sediments. However, these new advances in sensor technology, as well as increased data availability currently have not been fully explored for the study of salt pan environments. The potential of new sensors needs to be assessed and state of the art methods need to be adapted and improved to provide reliable information for in depth analysis of processes and characterisation of the recent condition, as well as to support long-term monitoring and to evaluate environmental impacts of changing climate and anthropogenic activity. This thesis provides an assessment of the capabilities of optical remote sensing for the study of salt pan environments that combines the information of hyperspectral data with the increased temporal coverage of multispectral observations for a more complete understanding of spatial and temporal complexity of salt pan environments using the Omongwa salt pan located in the south-west Kalahari as a test site. In particular, hyperspectral data are used for unmixing of the mineralogical surface composition, spectral feature-based modelling for quantification of main crust components, as well as time-series based classification of multispectral data for the assessment of the long-term dynamic and the analysis of the seasonal process regime. The results show that the surface of the Omongwa pan can be categorized into three major crust types based on diagnostic absorption features and mineralogical ground truth data. The mineralogical crust types can be related to different zones of surface dynamic as well as pan morphology that influences brine flow during the pan inundation and desiccation cycles. Using current hyperspectral imagery, as well as simulated data of upcoming sensors, robust quantification of the gypsum component could be derived. For the test site the results further indicate that the crust dynamic is mainly driven by flooding events in the wet season, but it is also influenced by temperature and aeolian activity in the dry season. Overall, the scientific outcomes show that optical remote sensing can provide a wide range of information helpful for the study of salt pan environments. The thesis also highlights that remote sensing approaches are most relevant, when they are adapted to the specific site conditions and research scenario and that upcoming sensors will increase the potential for mineralogical, sedimentological and geomorphological analysis, and will improve the monitoring capabilities with increased data availability.},
  language  = {en}
}
@phdthesis{Mitzscherling2020,
  author    = {Mitzscherling, Julia},
  title     = {Microbial communities in submarine permafrost and their response to permafrost degradation and warming},
  doi       = {10.25932/publishup-47124},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471240},
  school      = {Universit{\"a}t Potsdam},
  pages     = {I, 231},
  year      = {2020},
  abstract  = {The Arctic region is especially impacted by global warming as temperatures in high latitude regions have increased and are predicted to further rise at levels above the global average. This is crucial to Arctic soils and the shallow shelves of the Arctic Ocean as they are underlain by permafrost. Perennially frozen ground is a habitat for a large number and great diversity of viable microorganisms, which can remain active even under freezing conditions. Warming and thawing of permafrost makes trapped soil organic carbon more accessible to microorganisms. They can transform it to the greenhouse gases carbon dioxide, methane and nitrous oxide. On the other hand, it is assumed that thawing of the frozen ground stimulates microbial activity and carbon turnover. This can lead to a positive feedback loop of warming and greenhouse gas release. Submarine permafrost covers most areas of the Siberian Arctic Shelf and contains a large though unquantified carbon pool. However, submarine permafrost is not only affected by changes in the thermal regime but by drastic changes in the geochemical composition as it formed under terrestrial conditions and was inundated by Holocene sea level rise and coastal erosion. Seawater infiltration into permafrost sediments resulted in an increase of the pore water salinity and, thus, in thawing of permafrost in the upper sediment layers even at subzero temperatures. The permafrost below, which was not affected by seawater, remained ice-bonded, but warmed through seawater heat fluxes. The objective of this thesis was to study microbial communities in submarine permafrost with a focus on their response to seawater influence and long-term warming using a combined approach of molecular biological and physicochemical analyses. The microbial abundance, community composition and structure as well as the diversity were investigated in drill cores from two locations in the Laptev Sea, which were subjected to submarine conditions for centuries to millennia. The microbial abundance was measured through total cell counts and copy numbers of the 16S rRNA gene and of functional genes. The latter comprised genes which are indicative for methane production (mcrA) and sulfate reduction (dsrB). The microbial community was characterized by high-throughput-sequencing of the 16S rRNA gene. Physicochemical analyses included the determination of the pore water geochemical and stable isotopic composition, which were used to describe the degree of seawater influence. One major outcome of the thesis is that the submarine permafrost stratified into different so-called pore water units centuries as well as millennia after inundation: (i) sediments that were mixed with seafloor sediments, (ii) sediments that were infiltrated with seawater, and (iii) sediments that were unaffected by seawater. This stratification was reflected in the submarine permafrost microbial community composition only millennia after inundation but not on time-scales of centuries. Changes in the community composition as well as abundance were used as a measure for microbial activity and the microbial response to changing thermal and geochemical conditions. The results were discussed in the context of permafrost temperature, pore water composition, paleo-climatic proxies and sediment age. The combination of permafrost warming and increasing salinity as well as permafrost warming alone resulted in a disturbance of the microbial communities at least on time-scales of centuries. This was expressed by a loss of microbial abundance and bacterial diversity. At the same time, the bacterial community of seawater unaffected but warmed permafrost was mainly determined by environmental and climatic conditions at the time of sediment deposition. A stimulating effect of warming was observed only in seawater unaffected permafrost after millennia-scale inundation, visible through increased microbial abundance and reduced amounts of substrate. Despite submarine exposure for centuries to millennia, the community of bacteria in submarine permafrost still generally resembled the community of terrestrial permafrost. It was dominated by phyla like Actinobacteria, Chloroflexi, Firmicutes, Gemmatimonadetes and Proteobacteria, which can be active under freezing conditions. Moreover, the archaeal communities of both study sites were found to harbor high abundances of marine and terrestrial anaerobic methane oxidizing archaea (ANME). Results also suggested ANME populations to be active under in situ conditions at subzero temperatures. Modeling showed that potential anaerobic oxidation of methane (AOM) could mitigate the release of almost all stored or microbially produced methane from thawing submarine permafrost. Based on the findings presented in this thesis, permafrost warming and thawing under submarine conditions as well as permafrost warming without thaw are supposed to have marginal effects on the microbial abundance and community composition, and therefore likely also on carbon mobilization and the formation of methane. Thawing under submarine conditions even stimulates AOM and thus mitigates the release of methane.},
  language  = {en}
}
@phdthesis{Maerz2020,
  author    = {M{\"a}rz, Moses},
  title     = {{\´E}douard Glissant's politics of relation},
  doi       = {10.25932/publishup-50948},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-509486},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xv, 530},
  year      = {2020},
  abstract  = {The political legacy of the Martinican poet, novelist and philosopher {\´E}douard Glissant (1928-2011) is the subject of an ongoing debate among postcolonial literary scholars. Responding to an influential view shaping this debate, that Glissant's work can be categorised into an early political and late apolitical phase, this dissertation claims that this division is based on a narrow conception of 'engaged political writing' that prevents a more comprehensive view of the changing political strategies Glissant pursued throughout his life from emerging. Proceeding from this conceptual basis, the dissertation is concerned with re-reading the dimensions of Glissant's work that have hitherto been relegated as apolitical, literary or poetic, with the aim of conceptualising the politics of relation as an integral part of his overall poetic project. In methodological terms, the dissertation therefore proposes a relational reading of Glissant's life-work across literary genres, epochs, as well as the conventional divisions between political thought, writing and activism. This perspective is informed by Glissant's philosophy of relation, and draws on a conception of political practice that includes both explicit engagements with established political systems and institutions, as well as literary and cultural interventions geared towards their transformation and the creation of alternatives to them. Theoretically the work thus combines a poststructuralist lens on the conceptual difference between 'politics' and 'the political' with arguments for an inherent political quality of literature, and perspectives from the Afro-Caribbean radical tradition, in which writers and intellectuals have historically sought to combine discursive interventions with organisational actions. Applying this theoretical angle to the analysis of Glissant's politics of relation results in an interdisciplinary research framework designed to explore the synergies between postcolonial political and literary studies. In order to comprehensively describe Glissant's politics of relation without recourse to evolutionary or digressive models, the concept of an intellectual marronage is proposed as a framework to map the strategies making up Glissant's political archive. Drawing on a variety of historic, political theoretical and literary sources, intellectual marronage is understood as a mode of radical resistance to the neocolonial subjugation for which the plantation system stands historically and metaphorically, as an inherently innovative political practice invested in the creation of communities marked by relational ontologies, and as a commitment to fostering an imagination of the world and the human that differs fundamentally from the Enlightenment paradigm. This specific conception of intellectual marronage forms the basis on which three key strategies that consistently shape Glissant's political practice are identified and mapped. They revolve around Glissant's engagement with history (chapter 2), his commitment to fostering an imagination of the Tout-Monde (whole-world) as a political point of reference (chapter 3), and the continuous exploration of alternative forms of community on the levels of the island, the archipelago and the Tout-Monde (chapter 4). Together these strategies constitute Glissant's personal politics of relation. Its abstract characteristics can be put in a productive conversation with related theoretical traditions invested in exploring the political potentials of fugitivity (chapters 5), as well as with the work of other postcolonial actors whose holistic practice warrants to be described as a politics of relation (chapter 6).},
  language  = {en}
}
@phdthesis{Moerl2020,
  author    = {M{\"o}rl, Susann},
  title     = {Entwicklung und Erprobung konzeptioneller Grundlagen zur lernf{\"o}rderlichen Gestaltung von Kompetenzr{\"u}ckmeldungen bei der Praktischen Fahrerlaubnispr{\"u}fung},
  doi       = {10.25932/publishup-46854},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-468543},
  school      = {Universit{\"a}t Potsdam},
  pages     = {146},
  year      = {2020},
  abstract  = {Die Praktische Fahrerlaubnispr{\"u}fung dient der Erfassung und Beurteilung der Fahrkompe-tenz von Fahrerlaubnisbewerbern. Die aus dieser Pr{\"u}fung gewonnenen R{\"u}ckschl{\"u}sse auf das Niveau der Fahrkompetenz sollen insbesondere auch der Weiterentwicklung des Bewerbers dienen. Bisher erhalten Bewerber nur bei nicht bestandener Praktischer Fahrerlaubnispr{\"u}-fung eine Auflistung der wichtigsten Fehler, die zum Nichtbestehen gef{\"u}hrt haben. F{\"u}r ein zielgerichtetes Weiterlernen ist es aber notwendig, dass die Ergebnisse der Leistungserfas-sung und der Leistungsbewertung gem{\"a}ß pr{\"u}fungsdidaktischer Grunds{\"a}tze p{\"a}dagogisch an-spruchsvoll an alle Fahranf{\"a}nger (unabh{\"a}ngig vom Pr{\"u}fungsergebnis) zur{\"u}ckgemeldet wer-den. Das Ziel der vorliegenden Arbeit besteht darin, die Gestaltungsgrundlagen und einen Umset-zungsvorschlag f{\"u}r ein kompetenzbezogenes und lernf{\"o}rderliches R{\"u}ckmeldesystem f{\"u}r die Praktische Fahrerlaubnispr{\"u}fung zu erarbeiten. Dieses R{\"u}ckmeldesystem soll in der Praxis erprobt werden. Dar{\"u}ber hinaus sollen anhand einer Bewerberbefragung zur Nutzerzufrie-denheit Erkenntnisse f{\"u}r die Weiterentwicklung gewonnen werden. Der Entwicklungs- und Erprobungsprozess des optimierten R{\"u}ckmeldesystems l{\"a}sst sich in drei Projektphasen auf-teilen: 1. Im Zuge der Optimierungsarbeiten zur Praktischen Fahrerlaubnispr{\"u}fung wurde in der ersten Projektphase ein neues R{\"u}ckmeldesystem erarbeitet, das aus einem kompetenz-bezogenen m{\"u}ndlichen Auswertungsgespr{\"a}ch und einer erg{\"a}nzenden schriftlichen R{\"u}ckmeldung einschließlich weiterf{\"u}hrender Lernhinweise f{\"u}r alle Bewerber besteht. Dieses R{\"u}ckmeldesystem soll einerseits die Fahranf{\"a}nger dabei unterst{\"u}tzen, die Leis-tungsbewertung inhaltlich besser zu verstehen sowie ein zielgerichtetes Weiterlernen erm{\"o}glichen. Andererseits soll es die Bewerber dazu motivieren, die festgestellten Kompetenzdefizite weiter zu bearbeiten, und dadurch Lernzuwachs f{\"o}rdern. 2. Das R{\"u}ckmeldesystem wurde in der zweiten Projektphase in verschiedenen Modell- regionen Deutschlands anhand von ca. 9.000 realen Praktischen Fahrerlaubnispr{\"u}fun-gen erprobt. Die Fahrerlaubnisbewerber, die in den Modellregionen an einer optimier-ten Praktischen Fahrerlaubnispr{\"u}fung teilgenommen und somit eine schriftliche R{\"u}ckmeldung gem{\"a}ß der optimierten Vorgaben bzw. einen individuellen Zugangscode zum Downloadbereich erhalten haben, wurden zu einer Befragung eingeladen. Dabei wurden vor allem Aspekte der Akzeptanz und der Lernwirksamkeit aus Sicht der Be-werber erfasst. Ziel war es, die Qualit{\"a}t der verkehrsp{\"a}dagogischen Gestaltung des R{\"u}ckmeldesystems und seinen Nutzen zu untersuchen, um die erprobte R{\"u}ckmeldung weiterzuentwickeln. F{\"u}r die Bewerberbefragung wurde eine Onlinebefragung mit ei-nem standardisierten Fragebogen durchgef{\"u}hrt. 3. Die Erprobungs- und Befragungsergebnisse dienten in der dritten Projektphase der Ableitung von Schlussfolgerungen f{\"u}r die Weiterentwicklung des R{\"u}ckmeldesystems. Die vorliegenden Ergebnisse der Felderprobung deuten darauf hin, dass die Bereitstel-lung einer schriftlichen, ausf{\"u}hrlichen R{\"u}ckmeldung zu den Pr{\"u}fungsleistungen der Praktischen Fahrerlaubnispr{\"u}fungen insgesamt als n{\"u}tzlich und gewinnbringend ange-sehen wird. Allerdings wurde auch deutlich, dass bez{\"u}glich der Umsetzung noch Op-timierungspotenzial besteht. Im Anschluss an die Erprobung wurde die schriftliche R{\"u}ckmeldung daher - ausgehend von den Nutzererfahrungen w{\"a}hrend der Felderpro-bung - umfassend {\"u}berarbeitet und eine revidierte Version vorgelegt. Als Ergebnis der Arbeit liegt ein in mehreren Schritten entwickeltes, empirisch fundiertes und erprobtes R{\"u}ckmeldesystem vor, das eine differenzierte Kompetenzr{\"u}ckmeldung er-m{\"o}glicht. Die umfassende R{\"u}ckmeldung bietet k{\"u}nftig einerseits eine verbesserte Ausgangs-lage f{\"u}r eine ggf. anschließende Wiederholungspr{\"u}fung und andererseits ist es dem Bewer-ber anhand der aufgezeigten St{\"a}rken und Schw{\"a}chen auch nach einer bestandenen Pr{\"u}fung m{\"o}glich, diese R{\"u}ckmeldung f{\"u}r das weitere Lernen zu nutzen.},
  language  = {de}
}
@phdthesis{Mueller2020,
  author    = {M{\"u}ller, Jirka},
  title     = {Untersuchungen zum flow-Erleben bei Experimenten als physikalische Lerngelegenheit},
  doi       = {10.25932/publishup-48287},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-482879},
  school      = {Universit{\"a}t Potsdam},
  pages     = {150},
  year      = {2020},
  abstract  = {In der vorliegenden Arbeit wird untersucht, in wie weit physikalische Experimente ein flow-Erleben bei Lernenden hervorrufen. Flow-Erleben wird als Motivationsursache gesehen und soll den Weg zu Freude und Gl{\"u}ck darstellen. Insbesondere wegen dem oft zitierten Fachkr{\"a}ftemangel in naturwissenschaftlichen und technischen Berufen ist eine Motivationssteigerung in naturwissenschaftlichen Unterrichtsf{\"a}chern wichtig. Denn trotz Leistungssteigerungen in internationalen Vergleichstests m{\"o}chten in Deutschland deutlich weniger Sch{\"u}ler*innen einen solchen Beruf ergreifen als in anderen Industriestaaten. Daher gilt es, m{\"o}glichst fr{\"u}h Sch{\"u}ler*innen f{\"u}r naturwissenschaftlich-technische F{\"a}cher zu begeistern und insbesondere im regelrecht verhassten Physikunterricht flow-Erleben zu erzeugen. Im Rahmen dieser Arbeit wird das flow-Erleben von Studierenden in klassischen Laborexperimenten und FELS (Forschend-Entdeckendes Lernen mit dem Smartphone) als Lernumgebung untersucht. FELS ist eine an die Lebenswelt der Sch{\"u}ler*innen angepasste Lernumgebung, in der sie mit Smartphones ihre eigene Lebenswelt experimentell untersuchen. Es zeigt sich, dass sowohl klassische Laborexperimente als auch in der Lebenswelt durchgef{\"u}hrte, smartphonebasierte Experimente flow-Erleben erzeugen. Allerdings verursachen die smartphonebasierten Experimente kaum Stressgef{\"u}hle. Die in dieser Arbeit herausgefundenen Ergebnisse liefern einen ersten Ansatz, der durch Folgestudien erweitert werden sollte.},
  language  = {de}
}
@phdthesis{Nardini2020,
  author    = {Nardini, Livia},
  title     = {Influence of heterogeneities on the initiation of shear zones in the ductile regime},
  doi       = {10.25932/publishup-44616},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-446165},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIX, 121},
  year      = {2020},
  abstract  = {The current thesis contains the results from two experimental and one modelling study focused on the topic of ductile strain localization in the presence of material heterogeneities. Localization of strain in the high temperature regime is a well known feature of rock deformation occurring in nature at different scales and in a variety of lithologies. Large scale shear zones at the roots of major crustal fault zones are considered responsible for the activity of plate tectonics on our planet. A large number of mechanisms are suggested to be associated with strain softening and nucleation of localization. Among these, the presence of material heterogeneities within homogeneous host rocks is frequently observed in field examples to trigger shear zone development. Despite a number of studies conducted on the topic, the mechanisms controlling initiation and evolution of localization are not fully understood yet. We investigated, experimentally and by means of numerical modelling, phenomenological and microphysical aspects of high temperature strain localization in a homogeneous body containing single and paired inclusions of weaker material. A monomineralic carbonate system composed of Carrara marble (homogeneous, strong matrix) and Solnhofen limestone (weak planar inclusions) is selected for our studies based on its versatility as an experimental material and on the frequent occurrence of carbonate rocks at the core of natural shear zones. To explore the influence of different loading conditions on heterogeneity-induced high temperature shear zones we conducted torsion experiments under constant twist (deformation) rate and constant torque (stress) conditions in a Paterson-type deformation apparatus on hollow cylinders of marble containing single planar inclusions of limestone. At the imposed experimental conditions (900 ◦C temperature and 400 MPa confining pressure) both materials deform plastically and the marble is ≈ 9 times stronger than the limestone. The viscosity contrast between the two materials induces a perturbation of the stress field within the marble matrix at the tip of the planar inclusion. Early on along the deformation path (at bulk shear strains ≈ 0.3), heterogeneous distribution of strain can be observed under both loading conditions and a small area of incipient strain localization is formed at the tip of the weak limestone inclusion. Strongly deformed grains, incipient dynamic recrystallization and a weak crystallographic preferred orientation characterize the marble within an area a few mm in front of the inclusion. As the bulk strain is increased (up to γ ≈ 1), the area of microstructural modification is expanded along the inclusion plane, the texture strengthens and grain size refinement by dynamic recrystallization becomes pervasive. Locally, evidences for coexisting brittle deformation are also observed regardless of the imposed loading conditions. A shear zone is effectively formed within the deforming Carrara marble, its geometry controlled by the plane containing the thin plate of limestone. Thorough microstructural and textural analysis, however, do not reveal substantial differences in the mechanisms or magnitude of strain localization at the different loading conditions. We conclude that, in the presence of material heterogeneities capable of inducing strain softening, the imposed loading conditions do not affect ductile localization in its nucleating and transient stages. As the ultimate goal of experimental rock deformation is the extrapolation of results to geologically relevant time and space scales, we developed 2D numerical models reproducing (and benchmarked to) our experimental results. Our cm-scaled models have been implemented with a first-order strain-dependent softening law to reproduce the effect of rheological weakening in the deforming material. We successfully reproduced the local stress concentration at the inclusion tips and the strain localization initiated in the marble matrix. The heterogeneous distribution of strain and its evolution with imposed bulk deformation (i.e. the shape and extent of the nucleating shear zone) are observed to depend on the degree of softening imposed to the deforming matrix. When a second (artificial) softening step is introduced at elevated bulk strains in the model, the formation of a secondary high strain layer is observed at the core of the initial shear zone, analogous to the development of ultramylonite bands in high strain natural shear zones. Our results do not only reproduce the nucleation and transient evolution of a heterogeneity-induced high temperature shear zone with high accuracy, but also confirm the importance of introducing reliable softening laws capable of mimicking strain weakening to numerical models of crustal scale ductile processes. Material heterogeneities inducing strain localization in the field are often consisting of brittle precursors (joints and fractures). More generally, the interaction of brittle and ductile deformation mechanisms and its effect on the localization of strain have been a key topic in the structural geology community for a long time. The positive feedback between (micro)fracturing and ductile strain localization is a well recognized effect in a number of field examples. We experimentally investigated the influence of brittle deformation on the initiation and evolution of high temperature shear zones in a strong matrix containing pairs of weak material heterogeneities. Our Carrara marble-Solnhofen limestone inclusions system was tested in triaxial compression under constant strain rate and high temperature (900 ◦C) conditions in a Paterson deformation apparatus. The inclusion pairs were arranged in non-overlapping step-over geometries of either compressional or extensional nature. Experimental runs were conducted at different confining pressures (30, 50, 100 and 300 MPa) to induce various amounts of brittle deformation within the marble matrix. At low confinement (30 and 50 MPa) abundant brittle deformation is observed in all configurations, but the spatial distribution of cracks is dependent on the kinematics of the step-over region: concentrated along the shearing plane between the inclusions in the extensional samples, or broadly distributed around the inclusions but outside the step-over region in the compressional configuration. Accordingly, brittle-assisted ductile processes tend to localize deformation along the inclusions plane in the extensional geometry or to distribute widely across large areas of the matrix in the compressional step-over. At pressures of 100 and 300 MPa fracturing is mostly suppressed in both configurations and strain is accommodated almost entirely by viscous creep. In extensional samples this leads to progressive de-localization with increasing confinement. Our results show that, while ductile localization of strain is indeed more efficient where assisted by brittle processes, these latter are only effective if themselves heterogeneously distributed, ultimately a function of the local stress perturbations.},
  language  = {en}
}
@phdthesis{Neumann2020,
  author    = {Neumann, Justus},
  title     = {Secular evolution in galaxies},
  doi       = {10.25932/publishup-48270},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-482701},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 97},
  year      = {2020},
  abstract  = {Galaxies are gravitationally bound systems of stars, gas, dust and - probably - dark matter. They are the building blocks of the Universe. The morphology of galaxies is diverse: some galaxies have structures such as spirals, bulges, bars, rings, lenses or inner disks, among others. The main processes that characterise galaxy evolution can be separated into fast violent events that dominated evolution at earlier times and slower processes, which constitute a phase called secular evolution, that became dominant at later times. Internal processes of secular evolution include the gradual rearrangement of matter and angular momentum, the build-up and dissolution of substructures or the feeding of supermassive black holes and their feedback. Galaxy bulges - bright central components in disc galaxies -, on one hand, are relics of galaxy formation and evolution. For instance, the presence of a classical bulge suggests a relatively violent history. In contrast, the presence of a disc-like bulge instead indicates the occurrence of secular evolution processes in the main disc. Galaxy bars - elongated central stellar structures -, on the other hand, are the engines of secular evolution. Studying internal properties of both bars and bulges is key to comprehending some of the processes through which secular evolution takes place. The main objectives of this thesis are (1) to improve the classification of bulges by combining photometric and spectroscopic approaches for a large sample of galaxies, (2) to quantify star formation in bars and verify dependencies on galaxy properties and (3) to analyse stellar populations in bars to aid in understanding the formation and evolution of bars. Integral field spectroscopy is fundamental to the work presented in this thesis, which consists of three different projects as part of three different galaxy surveys: the CALIFA survey, the CARS survey and the TIMER project. The first part of this thesis constitutes an investigation of the nature of bulges in disc galaxies. We analyse 45 galaxies from the integral-field spectroscopic survey CALIFA by performing 2D image decompositions, growth curve measurements and spectral template fitting to derive stellar kinematics from CALIFA data cubes. From the obtained results, we present a recipe to classify bulges that combines four different parameters from photometry and kinematics: The bulge Sersic index nb, the concentration index C20;50, the Kormendy relation and the inner slope of the radial velocity dispersion profile ∇σ. The results of the different approaches are in good agreement and allow a safe classification for approximately 95\% of the galaxies. We also find that our new 'inner' concentration index performs considerably better than the traditionally used C50;90 and, in combination with the Kormendy relation, provides a very robust indication of the physical nature of the bulge. In the second part, we study star formation within bars using VLT/MUSE observations for 16 nearby (0.01 < z < 0.06) barred active-galactic-nuclei (AGN)-host galaxies from the CARS survey. We derive spatially-resolved star formation rates (SFR) from Hα emission line fluxes and perform a detailed multi-component photometric decomposition on images derived from the data cubes. We find a clear separation into eight star-forming (SF) and eight non-SF bars, which we interpret as indication of a fast quenching process. We further report a correlation between the SFR in the bar and the shape of the bar surface brightness profile: only the flattest bars (nbar < 0.4) are SF. Both parameters are found to be uncorrelated with Hubble type. Additionally, owing to the high spatial resolution of the MUSE data cubes, for the first time, we are able to dissect the SFR within the bar and analyse trends parallel and perpendicular to the bar major axis. Star formation is 1.75 times stronger on the leading edge of a rotating bar than on the trailing edge and is radially decreasing. Moreover, from testing an AGN feeding scenario, we report that the SFR of the bar is uncorrelated with AGN luminosity. Lastly, we present a detailed analysis of star formation histories and chemical enrichment of stellar populations (SP) in galaxy bars. We use MUSE observations of nine very nearby barred galaxies from the TIMER project to derive spatially resolved maps of stellar ages and metallicities, [α/Fe] abundances, star formation histories, as well as Hα as tracer of star formation. Using these maps, we explore in detail variations of SP perpendicular to the bar major axes. We find observational evidence for a separation of SP, supposedly caused by an evolving bar. Specifically, intermediate-age stars (∼ 2-6 Gyr) get trapped on more elongated orbits forming a thinner bar, while old stars (> 8 Gyr) form a rounder and thicker bar. This evidence is further strengthened by very similar results obtained from barred galaxies in the cosmological zoom-in simulations from the Auriga project. In addition, we find imprints of typical star formation patterns in barred galaxies on the youngest populations (< 2 Gyr), which continuously become more dominant from the major axis towards the sides of the bar. The effect is slightly stronger on the leading side. Furthermore, we find that bars are on average more metal-rich and less α-enhanced than the inner parts of the discs that surrounds them. We interpret this result as an indication of a more prolonged or continuous formation of stars that shape the bar as compared to shorter formation episodes in the disc within the bar region.},
  language  = {en}
}
@phdthesis{Nooshiri2020,
  author    = {Nooshiri, Nima},
  title     = {Improvement of routine seismic source parameter estimation based on regional and teleseismic recordings},
  doi       = {10.25932/publishup-45946},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459462},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 118},
  year      = {2020},
  abstract  = {Seismological agencies play an important role in seismological research and seismic hazard mitigation by providing source parameters of seismic events (location, magnitude, mechanism), and keeping these data accessible in the long term. The availability of catalogues of seismic source parameters is an important requirement for the evaluation and mitigation of seismic hazards, and the catalogues are particularly valuable to the research community as they provide fundamental long-term data in the geophysical sciences. This work is well motivated by the rising demand for developing more robust and efficient methods for routine source parameter estimation, and ultimately generation of reliable catalogues of seismic source parameters. Specifically, the aim of this work is to develop some methods to determine hypocentre location and temporal evolution of seismic sources based on regional and teleseismic observations more accurately, and investigate the potential of these methods to be integrated in near real-time processing. To achieve this, a location method that considers several events simultaneously and improves the relative location accuracy among nearby events has been provided. This method tries to reduce the biasing effects of the lateral velocity heterogeneities (or equivalently to compensate for limitations and inaccuracies in the assumed velocity model) by calculating a set of timing corrections for each seismic station. The systematic errors introduced into the locations by the inaccuracies in the assumed velocity structure can be corrected without explicitly solving for a velocity model. Application to sets of multiple earthquakes in complex tectonic environments with strongly heterogeneous structure such as subduction zones and plate boundary region demonstrate that this relocation process significantly improves the hypocentre locations compared to standard locations. To meet the computational demands of this location process, a new open-source software package has been developed that allows for efficient relocation of large-scale multiple seismic events using arrival time data. Upon that, a flexible location framework is provided which can be tailored to various application cases on local, regional, and global scales. The latest version of the software distribution including source codes, a user guide, an example data set, and a change history, is freely available to the community. The developed relocation algorithm has been modified slightly and then its performance in a simulated near real-time processing has been evaluated. It has been demonstrated that applying the proposed technique significantly reduces the bias in routine locations and enhance the ability to locate the lower magnitude events using only regional arrival data. Finally, to return to emphasis on global seismic monitoring, an inversion framework has been developed to determine the seismic source time function through direct waveform fitting of teleseismic recordings. The inversion technique can be systematically applied to moderate- size seismic events and has the potential to be performed in near real-time applications. It is exemplified by application to an abnormal seismic event; the 2017 North Korean nuclear explosion. The presented work and application case studies in this dissertation represent the first step in an effort to establish a framework for automatic, routine generation of reliable catalogues of seismic event locations and source time functions.},
  language  = {en}
}
@phdthesis{Nordmann2020,
  author    = {Nordmann, Paul-Patrick},
  title     = {Fehlerkorrektur von Speicherfehlern mit Low-Density-Parity-Check-Codes},
  doi       = {10.25932/publishup-48048},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-480480},
  school      = {Universit{\"a}t Potsdam},
  pages     = {IV, 99, XII},
  year      = {2020},
  abstract  = {Die Fehlerkorrektur in der Codierungstheorie besch{\"a}ftigt sich mit der Erkennung und Behebung von Fehlern bei der {\"U}bertragung und auch Sicherung von Nachrichten. Hierbei wird die Nachricht durch zus{\"a}tzliche Informationen in ein Codewort kodiert. Diese Kodierungsverfahren besitzen verschiedene Anspr{\"u}che, wie zum Beispiel die maximale Anzahl der zu korrigierenden Fehler und die Geschwindigkeit der Korrektur. Ein g{\"a}ngiges Codierungsverfahren ist der BCH-Code, welches industriell f{\"u}r bis zu vier Fehler korrigiere Codes Verwendung findet. Ein Nachteil dieser Codes ist die technische Durchlaufzeit f{\"u}r die Berechnung der Fehlerstellen mit zunehmender Codel{\"a}nge. Die Dissertation stellt ein neues Codierungsverfahren vor, bei dem durch spezielle Anordnung kleinere Codel{\"a}ngen eines BCH-Codes ein langer Code erzeugt wird. Diese Anordnung geschieht {\"u}ber einen weiteren speziellen Code, einem LDPC-Code, welcher f{\"u}r eine schneller Fehlererkennung konzipiert ist. Hierf{\"u}r wird ein neues Konstruktionsverfahren vorgestellt, welches einen Code f{\"u}r einen beliebige L{\"a}nge mit vorgebbaren beliebigen Anzahl der zu korrigierenden Fehler vorgibt. Das vorgestellte Konstruktionsverfahren erzeugt zus{\"a}tzlich zum schnellen Verfahren der Fehlererkennung auch eine leicht und schnelle Ableitung eines Verfahrens zu Kodierung der Nachricht zum Codewort. Dies ist in der Literatur f{\"u}r die LDPC-Codes bis zum jetzigen Zeitpunkt einmalig. Durch die Konstruktion eines LDPC-Codes wird ein Verfahren vorgestellt wie dies mit einem BCH-Code kombiniert wird, wodurch eine Anordnung des BCH-Codes in Bl{\"o}cken erzeugt wird. Neben der allgemeinen Beschreibung dieses Codes, wird ein konkreter Code f{\"u}r eine 2-Bitfehlerkorrektur beschrieben. Diese besteht aus zwei Teilen, welche in verschiedene Varianten beschrieben und verglichen werden. F{\"u}r bestimmte L{\"a}ngen des BCH-Codes wird ein Problem bei der Korrektur aufgezeigt, welche einer algebraischen Regel folgt. Der BCH-Code wird sehr allgemein beschrieben, doch existiert durch bestimmte Voraussetzungen ein BCH-Code im engerem Sinne, welcher den Standard vorgibt. Dieser BCH-Code im engerem Sinne wird in dieser Dissertation modifiziert, so dass das algebraische Problem bei der 2-Bitfehler Korrektur bei der Kombination mit dem LDPC-Code nicht mehr existiert. Es wird gezeigt, dass nach der Modifikation der neue Code weiterhin ein BCH-Code im allgemeinen Sinne ist, welcher 2-Bitfehler korrigieren und 3-Bitfehler erkennen kann. Bei der technischen Umsetzung der Fehlerkorrektur wird des Weiteren gezeigt, dass die Durchlaufzeiten des modifizierten Codes im Vergleich zum BCH-Code schneller ist und weiteres Potential f{\"u}r Verbesserungen besitzt. Im letzten Kapitel wird gezeigt, dass sich dieser modifizierte Code mit beliebiger L{\"a}nge eignet f{\"u}r die Kombination mit dem LDPC-Code, wodurch dieses Verfahren nicht nur umf{\"a}nglicher in der L{\"a}nge zu nutzen ist, sondern auch durch die schnellere Dekodierung auch weitere Vorteile gegen{\"u}ber einem BCH-Code im engerem Sinne besitzt.},
  language  = {de}
}
@phdthesis{Perovic2020,
  author    = {Perovic, Milena},
  title     = {Functionalization of nanoporous carbon materials for chiral separation and heterogeneous oxidation catalysis},
  doi       = {10.25932/publishup-48659},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-486594},
  school      = {Universit{\"a}t Potsdam},
  pages     = {140},
  year      = {2020},
  abstract  = {The impact that catalysis has on global economy and environment is substantial, since 85\% of all chemical industrial processes are catalytic. Among those, 80\% of the processes are heterogeneously catalyzed, 17\% make use of homogeneous catalysts, and 3\% are biocatalytic processes. Especially in the pharmaceutical and agrochemical industry, a significant part of these processes involves chiral compounds. Obtaining enantiomerically pure compounds is necessary and it is usually accomplished by asymmetric synthesis and catalysis, as well as chiral separation. The efficiency of these processes may be vastly improved if the chiral selectors are positioned on a porous solid support, thereby increasing the available surface area for chiral recognition. Similarly, the majority of commercial catalysts are also supported, usually comprising of metal nanoparticles (NPs) dispersed on highly porous oxide or nanoporous carbon material. Materials that have exceptional thermal and chemical stability, and are electrically conductive are porous carbons. Their stability in extreme pH regions and temperatures, the possibility to tailor their pore architecture and chemical functionalization, and their electric conductivity have already established these materials in the fields of separation and catalysis. However, their heterogeneous chemical structure with abundant defects make it challenging to develop reliable models for the investigation of structure-performance relationships. Therefore, there is a necessity for expanding the fundamental understanding of these robust materials under experimental conditions to allow for their further optimization for particular applications. This thesis gives a contribution to our knowledge about carbons, through different aspects, and in different applications. On the one hand, a rather exotic novel application was investigated by attempts in synthesizing porous carbon materials with an enantioselective surface. Chapter 4.1 described an approach for obtaining mesoporous carbons with an enantioselective surface by direct carbonization of a chiral precursor. Two enantiomers of chiral ionic liquids (CIL) based on amino acid tyrosine were used as carbon precursors and ordered mesoporous silica SBA-15 served as a hard template for obtaining porosity. The chiral recognition of the prepared carbons has been tested in the solution by isothermal titration calorimetry with enantiomers of Phenylalanine as probes, as well as chiral vapor adsorption with 2-butanol enantiomers. Measurements in both solution and the gas phase revealed the differences in the affinity of carbons towards two enantiomers. The atomic efficiency of the CIL precursors was increased in Chapter 4.2, and the porosity was developed independently from the development of chiral carbons, through the formation of stable composites of pristine carbon and CIL-derived coating. After the same set of experiments for the investigation of chirality, the enantiomeric ratios of the composites reported herein were even higher than in the previous chapter. On the other hand, the structure‒activity relationship of carbons as supports for gold nanoparticles in a rather traditional catalytic model reaction, on the interface between gas, liquid, and solid, was studied. In Chapter 5.1 it was shown on the series of catalysts with different porosities that the kinetics of ᴅ-glucose oxidation reaction can be enhanced by increasing the local concentration of the reactants around the active phase of the catalyst. A large amount of uniform narrow mesopores connected to the surface of the Au catalyst supported on ordered mesoporous carbon led to the water confinement, which increased the solubility of the oxygen in the proximity of the catalyst and thereby increased the apparent catalytic activity of this catalyst. After increasing the oxygen concentration in the internal area of the catalyst, in Chapter 5.2 the concentration of oxygen was increased in the external environment of the catalyst, by the introduction of less cohesive liquids that serve as efficient solvent for oxygen, perfluorinated compounds, near the active phase of the catalyst. This was achieved by a formation of catalyst particle-stabilized emulsions of perfluorocarbon in aqueous ᴅ-glucose solution, that further promoted the catalytic activity of gold-on-carbon catalyst. The findings reported within this thesis are an important step in the understanding of the structure-related properties of carbon materials.},
  language  = {en}
}
@phdthesis{Phung2020,
  author    = {Phung, Thi Thuy Nga},
  title     = {Defect chemistry in halide perovskites},
  doi       = {10.25932/publishup-47652},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-476529},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vi, 231},
  year      = {2020},
  abstract  = {Metallhalogenid-Perowskite haben sich aufgrund ihrer hervorragenden optoelektronischen Eigenschaften zu einer attraktiven Materialklasse f{\"u}r die Photovoltaikindustrie entwickelt. Die Langzeitstabilit{\"a}t ist jedoch noch immer ein Hindernis f{\"u}r die industrielle Realisierung dieser Materialklasse. Zunehmend zeigen sich Hinweise daf{\"u}r, dass intrinsische Defekte im Perowskit die Material-Degradation f{\"o}rdern. Das Verst{\"a}ndnis der Defekte im Perowskit ist wichtig, um seine Stabilit{\"a}t und optoelektronische Qualit{\"a}t weiter zu verbessern. Diese Dissertation konzentriert sich daher auf das Thema Defektchemie im Perowskit. Der erste Teil der Dissertation gibt einen kurzen {\"U}berblick {\"u}ber die Defekteigenschaften von Halogenid-Perowskiten. Anschließend zeigt der zweite Teil, dass das Dotieren von Methylammoniumbleiiodid mit einer kleinen Menge von Erdalkalimetallen (Sr und Mg) ein h{\"o}herwertiges, weniger fehlerhaftes Material erzeugt, was zu hohen Leerlaufspannungen sowohl in der n-i-p als auch in der p-i-n Architektur von Solarzellen f{\"u}hrt. Es wurde beobachtet, dass die Dotierung in zwei Dom{\"a}nen stattfindet: eine niedrige Dotierungskonzentration f{\"u}hrt zum Einschluss der entsprechenden Elemente in das Kristallgitter erm{\"o}glicht, w{\"a}hrend eine hohe Dotierungskonzentration zu einer Phasentrennung f{\"u}hrt. Das Material kann im Niedrigdotierungsbereich mehr n-dotiert sein, w{\"a}hrend es im Hochdotierungsbereich weniger n-dotiert ist. Die Schwelle dieser beiden Regime h{\"a}ngt von der Atomgr{\"o}ße der Dotierelemente ab. Der n{\"a}chste Teil der Dissertation untersucht die photoinduzierte Degradation von Methylammonium-Bleiiodid. Dieser Abbaumechanismus h{\"a}ngt eng mit der Bildung und Migration von defekten zusammen. Nach der Bildung k{\"o}nnen sich diese in Abh{\"a}ngigkeit von der Defektdichte und ihrer Verteilung bewegen. Demnach kann eine hohe Defektdichte wie an den Korngrenzen eines Perowskitfilms die Beweglichkeit von ionischen Punktdefekten hemmen. Diese Erkenntnis ließe sich auf das zuk{\"u}nftige Materialdesign in der Photovoltaikindustrie anwenden, da die Perowskit-Solarzellen normalerweise einen polykristallinen D{\"u}nnfilm mit hoher Korngrenzendichte verwenden. Die abschließende Studie, die in dieser Dissertation vorgestellt wird, konzentriert sich auf die Stabilit{\"a}t der neuesten „dreifach-kationen" Perowskit-basierten Solarzellen unter dem Einfluss einer permanent angelegten elektrischen Spannung. Eine l{\"a}ngere Betriebsdauer (mehr als drei Stunden permanente Spannung) f{\"o}rdert die Amorphisierung im Halogenid-Perowskiten. Es wird hierbei vermutet, dass sich eine amorphe Phase an den Grenzfl{\"a}chen bildet, insbesondere zwischen der lochselektiven Schicht und dem Perowskit. Diese amorphe Phase hemmt den Ladungstransport und beeintr{\"a}chtigt die Leistung der Perowskit-Solarzelle erheblich. Sobald jedoch keine Spannung mehr anliegt k{\"o}nnen sich die Perowskitschichten im Dunkeln bereits nach einer kurzen Pause regenerieren. Die Amorphisierung wird auf die Migration von ionischen Fehlordnungen zur{\"u}ckgef{\"u}hrt, h{\"o}chstwahrscheinlich auf die Migration von Halogeniden. Dieser Ansatz zeigt ein neues Verst{\"a}ndnis des Abbau-Mechanismus in Perowskit-Solarzellen unter Betriebsbedingungen.},
  language  = {en}
}
@phdthesis{Pick2020,
  author    = {Pick, Leonie Johanna Lisa},
  title     = {The centennial evolution of geomagnetic activity and its driving mechanisms},
  doi       = {10.25932/publishup-47275},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-472754},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 135},
  year      = {2020},
  abstract  = {This cumulative thesis is concerned with the evolution of geomagnetic activity since the beginning of the 20th century, that is, the time-dependent response of the geomagnetic field to solar forcing. The focus lies on the description of the magnetospheric response field at ground level, which is particularly sensitive to the ring current system, and an interpretation of its variability in terms of the solar wind driving. Thereby, this work contributes to a comprehensive understanding of long-term solar-terrestrial interactions. The common basis of the presented publications is formed by a reanalysis of vector magnetic field measurements from geomagnetic observatories located at low and middle geomagnetic latitudes. In the first two studies, new ring current targeting geomagnetic activity indices are derived, the Annual and Hourly Magnetospheric Currents indices (A/HMC). Compared to existing indices (e.g., the Dst index), they do not only extend the covered period by at least three solar cycles but also constitute a qualitative improvement concerning the absolute index level and the ~11-year solar cycle variability. The analysis of A/HMC shows that (a) the annual geomagnetic activity experiences an interval-dependent trend with an overall linear decline during 1900-2010 of ~5 \% (b) the average trend-free activity level amounts to ~28 nT (c) the solar cycle related variability shows amplitudes of ~15-45 nT (d) the activity level for geomagnetically quiet conditions (Kp<2) lies slightly below 20 nT. The plausibility of the last three points is ensured by comparison to independent estimations either based on magnetic field measurements from LEO satellite missions (since the 1990s) or the modeling of geomagnetic activity from solar wind input (since the 1960s). An independent validation of the longterm trend is problematic mainly because the sensitivity of the locally measured geomagnetic activity depends on geomagnetic latitude. Consequently, A/HMC is neither directly comparable to global geomagnetic activity indices (e.g., the aa index) nor to the partly reconstructed open solar magnetic flux, which requires a homogeneous response of the ground-based measurements to the interplanetary magnetic field and the solar wind speed. The last study combines a consistent, HMC-based identification of geomagnetic storms from 1930-2015 with an analysis of the corresponding spatial (magnetic local time-dependent) disturbance patterns. Amongst others, the disturbances at dawn and dusk, particularly their evolution during the storm recovery phases, are shown to be indicative of the solar wind driving structure (Interplanetary Coronal Mass Ejections vs. Stream or Co-rotating Interaction Regions), which enables a backward-prediction of the storm driver classes. The results indicate that ICME-driven geomagnetic storms have decreased since 1930 which is consistent with the concurrent decrease of HMC. Out of the collection of compiled follow-up studies the inclusion of measurements from high-latitude geomagnetic observatories into the third study's framework seems most promising at this point.},
  language  = {en}
}
@phdthesis{Pilz2020,
  author    = {Pilz, Tobias},
  title     = {Pursuing the understanding of uncertainties in hydrological modelling},
  doi       = {10.25932/publishup-47664},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-476643},
  school      = {Universit{\"a}t Potsdam},
  pages     = {136},
  year      = {2020},
  abstract  = {Hydrological models are important tools for the simulation and quantification of the water cycle. They therefore aid in the understanding of hydrological processes, prediction of river discharge, assessment of the impacts of land use and climate changes, or the management of water resources. However, uncertainties associated with hydrological modelling are still large. While significant research has been done on the quantification and reduction of uncertainties, there are still fields which have gained little attention so far, such as model structural uncertainties that are related to the process implementations in the models. This holds especially true for complex process-based models in contrast to simpler conceptual models. Consequently, the aim of this thesis is to improve the understanding of structural uncertainties with focus on process-based hydrological modelling, including methods for their quantification. To identify common deficits of frequently used hydrological models and develop further strategies on how to reduce them, a survey among modellers was conducted. It was found that there is a certain degree of subjectivity in the perception of modellers, for instance with respect to the distinction of hydrological models into conceptual groups. It was further found that there are ambiguities on how to apply a certain hydrological model, for instance how many parameters should be calibrated, together with a large diversity of opinion regarding the deficits of models. Nevertheless, evapotranspiration processes are often represented in a more physically based manner, while processes of groundwater and soil water movement are often simplified, which many survey participants saw as a drawback. A large flexibility, for instance with respect to different alternative process implementations or a small number of parameters that needs to be calibrated, was generally seen as strength of a model. Flexible and efficient software, which is straightforward to apply, has been increasingly acknowledged by the hydrological community. This work further elaborated on this topic in a twofold way. First, a software package for semi-automated landscape discretisation has been developed, which serves as a tool for model initialisation. This was complemented by a sensitivity analysis of important and commonly used discretisation parameters, of which the size of hydrological sub-catchments as well as the size and number of hydrologically uniform computational units appeared to be more influential than information considered for the characterisation of hillslope profiles. Second, a process-based hydrological model has been implemented into a flexible simulation environment with several alternative process representations and a number of numerical solvers. It turned out that, even though computation times were still long, enhanced computational capabilities nowadays in combination with innovative methods for statistical analysis allow for the exploration of structural uncertainties of even complex process-based models, which up to now was often neglected by the modelling community. In a further study it could be shown that process-based models may even be employed as tools for seasonal operational forecasting. In contrast to statistical models, which are faster to initialise and to apply, process-based models produce more information in addition to the target variable, even at finer spatial and temporal scales, and provide more insights into process behaviour and catchment functioning. However, the process-based model was much more dependent on reliable rainfall forecasts. It seems unlikely that there exists a single best formulation for hydrological processes, even for a specific catchment. This supports the use of flexible model environments with alternative process representations instead of a single model structure. However, correlation and compensation effects between process formulations, their parametrisation, and other aspects such as numerical solver and model resolution, may lead to surprising results and potentially misleading conclusions. In future studies, such effects should be more explicitly addressed and quantified. Moreover, model functioning appeared to be highly dependent on the meteorological conditions and rainfall input generally was the most important source of uncertainty. It is still unclear, how this could be addressed, especially in the light of the aforementioned correlations. The use of innovative data products, e.g.\ remote sensing data in combination with station measurements, and efficient processing methods for the improvement of rainfall input and explicit consideration of associated uncertainties is advisable to bring more insights and make hydrological simulations and predictions more reliable.},
  language  = {en}
}
@phdthesis{Pudell2020,
  author    = {Pudell, Jan-Etienne},
  title     = {Lattice dynamics},
  doi       = {10.25932/publishup-48445},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-484453},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XII, 259},
  year      = {2020},
  abstract  = {In this thesis I summarize my contribution to the research field of ultrafast structural dynamics in condensend matter. It consists of 17 publications that cover the complex interplay between electron, magnon, and phonon subsystems in solid materials and the resulting lattice dynamics after ultrafast photoexcitation. The investigation of such dynamics is necessary for the physical understanding of the processes in materials that might become important in the future as functional materials for technological applications, for example in data storage applications, information processing, sensors, or energy harvesting. In this work I present ultrafast x-ray diffraction (UXRD) experiments based on the optical pump - x-ray probe technique revealing the time-resolved lattice strain. To study these dynamics the samples (mainly thin film heterostructures) are excited by femtosecond near-infrared or visible light pulses. The induced strain dynamics caused by stresses of the excited subsystems are measured in a pump-probe scheme with x-ray diffraction (XRD) as a probe. The UXRD setups used during my thesis are a laser-driven table-top x-ray source and large-scale synchrotron facilities with dedicated time-resolved diffraction setups. The UXRD experiments provide quantitative access to heat reservoirs in nanometric layers and monitor the transient responses of these layers with coupled electron, magnon, and phonon subsystems. In contrast to optical probes, UXRD allows accessing the material-specific information, which is unavailable for optical light due to the detection of multiple indistinguishable layers in the range of the penetration depth. In addition, UXRD facilitates a layer-specific probe for layers buried opaque heterostructures to study the energy flow. I extended this UXRD technique to obtain the driving stress profile by measuring the strain dynamics in the unexcited buried layer after excitation of the adjacent absorbing layers with femtosecond laser pulses. This enables the study of negative thermal expansion (NTE) in magnetic materials, which occurs due to the loss of the magnetic order. Part of this work is the investigation of stress profiles which are the source of coherent acoustic phonon wave packets (hypersound waves). The spatiotemporal shape of these stress profiles depends on the energy distribution profile and the ability of the involved subsystems to produce stress. The evaluation of the UXRD data of rare-earth metals yields a stress profile that closely matches the optical penetration profile: In the paramagnetic (PM) phase the photoexcitation results in a quasi-instantaneous expansive stress of the metallic layer whereas in the antiferromagnetic (AFM) phase a quasi-instantaneous contractive stress and a second contractive stress contribution rising on a 10 ps time scale adds to the PM contribution. These two time scales are characteristic for the magnetic contribution and are in agreement with related studies of the magnetization dynamics of rare-earth materials. Several publications in this thesis demonstrate the scientific progress in the field of active strain control to drive a second excitation or engineer an ultrafast switch. These applications of ultrafast dynamics are necessary to enable control of functional material properties via strain on ultrafast time scales. For this thesis I implemented upgrades of the existing laser-driven table-top UXRD setup in order to achieve an enhancement of x-ray flux to resolve single digit nanometer thick layers. Furthermore, I developed and built a new in-situ time-resolved magneto-optic Kerr effect (MOKE) and optical reflectivity setup at the laser-driven table-top UXRD setup to measure the dynamics of lattice, electrons and magnons under the same excitation conditions.},
  language  = {en}
}
@phdthesis{Purinton2020,
  author    = {Purinton, Benjamin},
  title     = {Remote sensing applications to earth surface processes in the Eastern Central Andes},
  doi       = {10.25932/publishup-44592},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445926},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiii, 134},
  year      = {2020},
  abstract  = {Geomorphology seeks to characterize the forms, rates, and magnitudes of sediment and water transport that sculpt landscapes. This is generally referred to as earth surface processes, which incorporates the influence of biologic (e.g., vegetation), climatic (e.g., rainfall), and tectonic (e.g., mountain uplift) factors in dictating the transport of water and eroded material. In mountains, high relief and steep slopes combine with strong gradients in rainfall and vegetation to create dynamic expressions of earth surface processes. This same rugged topography presents challenges in data collection and process measurement, where traditional techniques involving detailed observations or physical sampling are difficult to apply at the scale of entire catchments. Herein lies the utility of remote sensing. Remote sensing is defined as any measurement that does not disturb the natural environment, typically via acquisition of images in the visible- to radio-wavelength range of the electromagnetic spectrum. Remote sensing is an especially attractive option for measuring earth surface processes, because large areal measurements can be acquired at much lower cost and effort than traditional methods. These measurements cover not only topographic form, but also climatic and environmental metrics, which are all intertwined in the study of earth surface processes. This dissertation uses remote sensing data ranging from handheld camera-based photo surveying to spaceborne satellite observations to measure the expressions, rates, and magnitudes of earth surface processes in high-mountain catchments of the Eastern Central Andes in Northwest Argentina. This work probes the limits and caveats of remote sensing data and techniques applied to geomorphic research questions, and presents important progress at this disciplinary intersection.},
  language  = {en}
}
@phdthesis{RamezaniZiarani2020,
  author    = {Ramezani Ziarani, Maryam},
  title     = {Characterization of atmospheric processes related to hydro-meteorological extreme events over the south-central Andes},
  doi       = {10.25932/publishup-47175},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471755},
  school      = {Universit{\"a}t Potsdam},
  pages     = {i, 88},
  year      = {2020},
  abstract  = {The significant environmental and socioeconomic consequences of hydrometeorological extreme events, such as extreme rainfall, are constituted as a most important motivation for analyzing these events in the south-central Andes of NW Argentina. The steep topographic and climatic gradients and their interactions frequently lead to the formation of deep convective storms and consequently trigger extreme rainfall generation. In this dissertation, I focus on identifying the dominant climatic variables and atmospheric conditions and their spatiotemporal variability leading to deep convection and extreme rainfall in the south-central Andes. This dissertation first examines the significant contribution of temperature on atmospheric humidity (dew-point temperature, Td) and on convection (convective available potential energy, CAPE) for deep convective storms and hence, extreme rainfall along the topographic and climatic gradients. It was found that both climatic variables play an important role in extreme rainfall generation. However, their contributions differ depending on topographic and climatic sub-regions, as well as rainfall percentiles. Second, this dissertation explores if (near real-time) the measurements conducted by the Global Navigation Satellite System (GNSS) on integrated water vapor (IWV) provide reliable data for explaining atmospheric humidity. I argue that GNSS-IWV, in conjunction with other atmospheric stability parameters such as CAPE, is able to decipher the extreme rainfall in the eastern central Andes. In my work, I rely on a multivariable regression analysis described by a theoretical relationship and fitting function analysis. Third, this dissertation identifies the local impact of convection on extreme rainfall in the eastern Andes. Relying on a Principal Component Analysis (PCA) it was found that during the existence of moist and warm air, extreme rainfall is observed more often during local night hours. The analysis includes the mechanisms for this observation. Exploring the atmospheric conditions and climatic variables leading to extreme rainfall is one of the main findings of this dissertation. The conditions and variables are a prerequisite for understanding the dynamics of extreme rainfall and predicting these events in the eastern Andes.},
  language  = {en}
}
@phdthesis{Reinhardt2020,
  author    = {Reinhardt, Maria},
  title     = {Hybrid filters and multi-scale models},
  doi       = {10.25932/publishup-47435},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-474356},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiii, 102},
  year      = {2020},
  abstract  = {This thesis is concerned with Data Assimilation, the process of combining model predictions with observations. So called filters are of special interest. One is inter- ested in computing the probability distribution of the state of a physical process in the future, given (possibly) imperfect measurements. This is done using Bayes' rule. The first part focuses on hybrid filters, that bridge between the two main groups of filters: ensemble Kalman filters (EnKF) and particle filters. The first are a group of very stable and computationally cheap algorithms, but they request certain strong assumptions. Particle filters on the other hand are more generally applicable, but computationally expensive and as such not always suitable for high dimensional systems. Therefore it exists a need to combine both groups to benefit from the advantages of each. This can be achieved by splitting the likelihood function, when assimilating a new observation and treating one part of it with an EnKF and the other part with a particle filter. The second part of this thesis deals with the application of Data Assimilation to multi-scale models and the problems that arise from that. One of the main areas of application for Data Assimilation techniques is predicting the development of oceans and the atmosphere. These processes involve several scales and often balance rela- tions between the state variables. The use of Data Assimilation procedures most often violates relations of that kind, which leads to unrealistic and non-physical pre- dictions of the future development of the process eventually. This work discusses the inclusion of a post-processing step after each assimilation step, in which a minimi- sation problem is solved, which penalises the imbalance. This method is tested on four different models, two Hamiltonian systems and two spatially extended models, which adds even more difficulties.},
  language  = {en}
}
@phdthesis{Renz2020,
  author    = {Renz, Jan},
  title     = {Lebensbegleitendes Lernen in einer digitalen Welt},
  doi       = {10.25932/publishup-47257},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-472573},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vii, 184},
  year      = {2020},
  abstract  = {In unserer digitalisierten Welt verlagert sich das Lernen in die Cloud. Vom Unterricht in der Schule und der Tafel zum Tablet, hin zu einem lebenslangen Lernen in der Arbeitswelt und sogar dar{\"u}ber hinaus. Wie erfolgreich und attraktiv dieses zeitgem{\"a}ße Lernen erfolgt, h{\"a}ngt nicht unwesentlich von den technologischen M{\"o}glichkeiten ab, die digitale Lernplattformen rund um MOOCs und Schul-Clouds bieten. Bei deren Weiterentwicklung sollten statt {\"o}konomischen Messgr{\"o}ßen und KPIs die Lernenden und ihre Lernerfahrungen im Vordergrund stehen. Hierf{\"u}r wurde ein Optimierungsframework entwickelt, das f{\"u}r die Entwicklung von Lernplattformen anhand verschiedener qualitativer und quantitative Methoden Verbesserungen identifiziert, priorisiert und deren Beurteilung und Umsetzung steuert. Datengest{\"u}tzte Entscheidungen sollten auf einer ausreichenden Datenbasis aufbauen. Moderne Web-Anwendungen bestehen aber oft aus mehreren Microservices mit jeweils eigener Datenhaltung. Viele Daten sind daher nicht mehr einfach zug{\"a}nglich. Daher wird in dieser Arbeit ein Learning Analytics Dienst eingef{\"u}hrt, der diese Daten sammelt und verarbeitet. Darauf aufbauend werden Metriken eingef{\"u}hrt, auf deren Grundlage die erfassten Daten nutzbar werden und die somit zu verschiedenen Zwecken verwendet werden k{\"o}nnen. Neben der Visualisierung der Daten in Dashboards werden die Daten f{\"u}r eine automatisierte Qualit{\"a}tskontrolle herangezogen. So kann festgestellt werden, wenn Tests zu schwierig oder die soziale Interaktion in einem MOOC zu gering ist. Die vorgestellte Infrastruktur l{\"a}sst sich aber auch verwenden, um verschiedene A/B/n-Tests durchzuf{\"u}hren. In solchen Tests gibt es mehrere Varianten, die an verschiedene Nutzergruppen in einem kontrollierten Experiment erprobt werden. Dank der vorgestellten Testinfrastruktur, die in der HPI MOOC Plattform eingebaut wurde, kann ermittelt werden, ob sich f{\"u}r diese Gruppen statistisch signifikante {\"A}nderungen in der Nutzung feststellen lassen. Dies wurde mit f{\"u}nf verschiedenen Verbesserungen der HPI MOOC Plattform evaluiert, auf der auch openHPI und openSAP basieren. Dabei konnte gezeigt werden, dass sich Lernende mit reaktivierenden Mails zur{\"u}ck in den Kurs holen lassen. Es ist prim{\"a}r die Kommunikation der unbearbeiteten Lerninhalte des Nutzers, die eine reaktivierende Wirkung hat. Auch {\"U}bersichtsmails, die die Forenaktivit{\"a}t zusammenfassen, haben einen positiven Effekt erzielt. Ein gezieltes On-Boarding kann dazu f{\"u}hren, dass die Nutzer die Plattform besser verstehen und hierdurch aktiver sind. Der vierte Test konnte zeigen, dass die Zuordnung von Forenfragen zu einem bestimmten Zeitpunkt im Video und die grafische Anzeige dieser Informationen zu einer erh{\"o}hten Forenaktivit{\"a}t f{\"u}hrt. Auch die experimentelle Erprobung von unterschiedlichen Lernmaterialien, wie sie im f{\"u}nften Test durchgef{\"u}hrt wurde, ist in MOOCs hilfreich, um eine Verbesserung der Kursmaterialien zu erreichen. Neben diesen funktionalen Verbesserungen wird untersucht wie MOOC Plattformen und Schul-Clouds einen Nutzen bieten k{\"o}nnen, wenn Nutzern nur eine schwache oder unzuverl{\"a}ssige Internetanbindung zur Verf{\"u}gung steht (wie dies in vielen deutschen Schulen der Fall ist). Hier wird gezeigt, dass durch ein geschicktes Vorausladen von Daten die Internetanbindungen entlastet werden k{\"o}nnen. Teile der Lernanwendungen funktionieren dank dieser Anpassungen, selbst wenn keine Verbindung zum Internet besteht. Als Letztes wird gezeigt, wie Endger{\"a}te sich in einem lokalen Peer-to-Peer CDN gegenseitig mit Daten versorgen k{\"o}nnen, ohne dass diese aus dem Internet heruntergeladen werden m{\"u}ssen.},
  language  = {de}
}
@phdthesis{Rietze2020,
  author    = {Rietze, Clemens},
  title     = {Optimierung und Analyse von molekularen Schaltern in komplexen Umgebungen: thermische Stabilit{\"a}t, Auslesbarkeit und Schaltbarkeit},
  doi       = {10.25932/publishup-45959},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-459594},
  school      = {Universit{\"a}t Potsdam},
  pages     = {131},
  year      = {2020},
  abstract  = {Seit Jahrzehnten stellen die molekularen Schalter ein wachsendes Forschungsgebiet dar. Im Rahmen dieser Dissertation stand die Verbesserung der thermischen Stabilit{\"a}t, der Auslesbarkeit und Schaltbarkeit dieser molekularen Schalter in komplexen Umgebungen mithilfe computergest{\"u}tzter Chemie im Vordergrund. Im ersten Projekt wurde die Kinetik der thermischen E → Z-Isomerisierung und die damit verbundene thermische Stabilit{\"a}t eines Azobenzol-Derivats untersucht. Daf{\"u}r wurde Dichtefunktionaltheorie (DFT) in Verbindung mit der Eyring-Theorie des {\"U}bergangszustandes (TST) angewendet. Das Azobenzol-Derivat diente als vereinfachtes Modell f{\"u}r das Schalten in einer komplexen Umgebung (hier in metallorganischen Ger{\"u}sten). Es wurden thermodynamische und kinetische Gr{\"o}ßen unter verschiedenen Einfl{\"u}ssen berechnet, wobei gute {\"U}bereinstimmungen mit dem Experiment gefunden wurden. Die hier verwendete Methode stellte einen geeigneten Ansatz dar, um diese Gr{\"o}ßen mit angemessener Genauigkeit vorherzusagen. Im zweiten Projekt wurde die Auslesbarkeit der Schaltzust{\"a}nde in Form des nichtlinearen optischen (NLO) Kontrastes f{\"u}r die Molek{\"u}lklasse der Fulgimide untersucht. Die daf{\"u}r ben{\"o}tigten dynamischen Hyperpolarisierbarkeiten unter Ber{\"u}cksichtigung der Elektronenkorrelation wurden mittels einer etablierten Skalierungsmethode berechnet. Es wurden verschiedene Fulgimide analysiert, wobei viele experimentelle Befunde best{\"a}tigt werden konnten. Dar{\"u}ber hinaus legte die theoretische Vorhersage f{\"u}r ein weiteres System nahe, dass insbesondere die Erweiterung des π-Elektronensystems ein vielversprechender Ansatz zur Verbesserung von NLO-Kontrasten darstellt. Die Fulgimide verf{\"u}gen somit {\"u}ber n{\"u}tzliche Eigenschaften, sodass diese in Zukunft als Bauelemente in photonischen und optoelektronischen Bereichen Anwendungen finden k{\"o}nnten. Im dritten Projekt wurde die E → Z-Isomerisierung auf ein quantenmechanisch (QM) behandeltes Dimer mit molekularmechanischer (MM) Umgebung und zwei Fluorazobenzol-Monomeren durch Molek{\"u}ldynamik simuliert. Dadurch wurde die Schaltbarkeit in komplexer Umgebung (hier selbstorgansierte Einzelschichten = SAMs) bzw. von Azobenzolderivaten analysiert. Mit dem QM/MM Modell wurden sowohl Van-der-Waals-Interaktionen mit der Umgebung als auch elektronische Kopplung (nur zwischen QM-Molek{\"u}len) ber{\"u}cksichtigt. Dabei wurden systematische Untersuchungen zur Packungsdichte durchgef{\"u}hrt. Es zeigte sich, dass bereits bei einem Molek{\"u}labstand von 4.5 {\AA} die Quantenausbeute (prozentuale Anzahl erfolgreicher Schaltprozesse) des Monomers erreicht wird. Die gr{\"o}ßten Quantenausbeuten wurden f{\"u}r die beiden untersuchten Fluorazobenzole erzielt. Es wurden die Effekte des Molek{\"u}labstandes und der Einfluss von Fluorsubstituenten auf die Dynamik eingehend untersucht, sodass der Weg f{\"u}r darauf aufbauende Studien geebnet ist.},
  language  = {de}
}
@phdthesis{Risch2020,
  author    = {Risch, Julian},
  title     = {Reader comment analysis on online news platforms},
  doi       = {10.25932/publishup-48922},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-489222},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xi, 135},
  year      = {2020},
  abstract  = {Comment sections of online news platforms are an essential space to express opinions and discuss political topics. However, the misuse by spammers, haters, and trolls raises doubts about whether the benefits justify the costs of the time-consuming content moderation. As a consequence, many platforms limited or even shut down comment sections completely. In this thesis, we present deep learning approaches for comment classification, recommendation, and prediction to foster respectful and engaging online discussions. The main focus is on two kinds of comments: toxic comments, which make readers leave a discussion, and engaging comments, which make readers join a discussion. First, we discourage and remove toxic comments, e.g., insults or threats. To this end, we present a semi-automatic comment moderation process, which is based on fine-grained text classification models and supports moderators. Our experiments demonstrate that data augmentation, transfer learning, and ensemble learning allow training robust classifiers even on small datasets. To establish trust in the machine-learned models, we reveal which input features are decisive for their output with attribution-based explanation methods. Second, we encourage and highlight engaging comments, e.g., serious questions or factual statements. We automatically identify the most engaging comments, so that readers need not scroll through thousands of comments to find them. The model training process builds on upvotes and replies as a measure of reader engagement. We also identify comments that address the article authors or are otherwise relevant to them to support interactions between journalists and their readership. Taking into account the readers' interests, we further provide personalized recommendations of discussions that align with their favored topics or involve frequent co-commenters. Our models outperform multiple baselines and recent related work in experiments on comment datasets from different platforms.},
  language  = {en}
}
@phdthesis{RodriguezZuluaga2020,
  author    = {Rodriguez Zuluaga, Juan},
  title     = {Electric and magnetic characteristics of equatorial plasma depletions},
  doi       = {10.25932/publishup-44587},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445873},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvi, 87},
  year      = {2020},
  abstract  = {Near-Earth space represents a significant scientific and technological challenge. Particularly at magnetic low-latitudes, the horizontal magnetic field geometry at the dip equator and its closed field-lines support the existence of a distinct electric current system, abrupt electric field variations and the development of plasma irregularities. Of particular interest are small-scale irregularities associated with equatorial plasma depletions (EPDs). They are responsible for the disruption of trans-ionospheric radio waves used for navigation, communication, and Earth observation. The fast increase of satellite missions makes it imperative to study the near-Earth space, especially the phenomena known to harm space technology or disrupt their signals. EPDs correspond to the large-scale structure (i.e., tens to hundreds of kilometers) of topside F region irregularities commonly known as Spread F. They are observed as depleted-plasma density channels aligned with the ambient magnetic field in the post-sunset low-latitude ionosphere. Although the climatological variability of their occurrence in terms of season, longitude, local time and solar flux is well-known, their day to day variability is not. The sparse observations from ground-based instruments like radars and the few simultaneous measurements of ionospheric parameters by space-based instruments have left gaps in the knowledge of EPDs essential to comprehend their variability. In this dissertation, I profited from the unique observations of the ESA's Swarm constellation mission launched in November 2013 to tackle three issues that revealed novel and significant results on the current knowledge of EPDs. I used Swarm's measurements of the electron density, magnetic, and electric fields to answer, (1.) what is the direction of propagation of the electromagnetic energy associated with EPDs?, (2.) what are the spatial and temporal characteristics of the electric currents (field-aligned and diamagnetic currents) related to EPDs, i.e., seasonal/geographical, and local time dependencies?, and (3.) under what conditions does the balance between magnetic and plasma pressure across EPDs occur? The results indicate that: (1.) The electromagnetic energy associated with EPDs presents a preference for interhemispheric flows; that is, the related Poynting flux directs from one magnetic hemisphere to the other and varies with longitude and season. (2.) The field-aligned currents at the edges of EPDs are interhemispheric. They generally close in the hemisphere with the highest Pedersen conductance. Such hemispherical preference presents a seasonal/longitudinal dependence. The diamagnetic currents increase or decrease the magnetic pressure inside EPDs. These two effects rely on variations of the plasma temperature inside the EPDs that depend on longitude and local time. (3.) EPDs present lower or higher plasma pressure than the ambient. For low-pressure EPDs the plasma pressure gradients are mostly dominated by variations of the plasma density so that variations of the temperature are negligible. High-pressure EPDs suggest significant temperature variations with magnitudes of approximately twice the ambient. Since their occurrence is more frequent in the vicinity of the South Atlantic magnetic anomaly, such high temperatures are suggested to be due to particle precipitation. In a broader context, this dissertation shows how dedicated satellite missions with high-resolution capabilities improve the specification of the low-latitude ionospheric electrodynamics and expand knowledge on EPDs which is valuable for current and future communication, navigation, and Earth-observing missions. The contributions of this investigation represent several 'firsts' in the study of EPDs: (1.) The first observational evidence of interhemispheric electromagnetic energy flux and field-aligned currents. (2.) The first spatial and temporal characterization of EPDs based on their associated field-aligned and diamagnetic currents. (3.) The first evidence of high plasma pressure in regions of depleted plasma density in the ionosphere. These findings provide new insights that promise to advance our current knowledge of not only EPDs but the low-latitude post-sunset ionosphere environment.},
  language  = {en}
}
@phdthesis{Rolf2020,
  author    = {Rolf, Werner},
  title     = {Peri-urban farmland included in green infrastructure strategies promotes transformation pathways towards sustainable urban development},
  doi       = {10.25932/publishup-47700},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-477002},
  school      = {Universit{\"a}t Potsdam},
  pages     = {IV, 116},
  year      = {2020},
  abstract  = {Urbanization and agricultural land use are two of the main drivers of global changes with effects on ecosystem functions and human wellbeing. Green Infrastructure is a new approach in spatial planning contributing to sustainable urban development, and to address urban challenges, such as biodiversity conservation, climate change adaptation, green economy development, and social cohesion. Because the research focus has been mainly on open green space structures, such as parks, urban forest, green building, street green, but neglected spatial and functional potentials of utilizable agricultural land, this thesis aims at fill this gap. This cumulative thesis addresses how agricultural land in urban and peri-urban landscapes can contribute to the development of urban green infrastructure as a strategy to promote sustainable urban development. Therefore, a number of different research approaches have been applied. First, a quantitative, GIS-based modeling approach looked at spatial potentials, addressing the heterogeneity of peri-urban landscape that defines agricultural potentials and constraints. Second, a participatory approach was applied, involving stakeholder opinions to evaluate multiple urban functions and benefits. Finally, an evidence synthesis was conducted to assess the current state of research on evidence to support future policy making at different levels. The results contribute to the conceptual understanding of urban green infrastructures as a strategic spatial planning approach that incorporates inner-urban utilizable agricultural land and the agriculturally dominated landscape at the outer urban fringe. It highlights the proposition that the linkage of peri-urban farmland with the green infrastructure concept can contribute to a network of multifunctional green spaces to provide multiple benefits to the urban system and to successfully address urban challenges. Four strategies are introduced for spatial planning with the contribution of peri-urban farmland to a strategically planned multifunctional network, namely the connecting, the productive, the integrated, and the adapted way. Finally, this thesis sheds light on the opportunities that arise from the integration of the peri- urban farmland in the green infrastructure concept to support transformation towards a more sustainable urban development. In particular, the inherent core planning principle of multifunctionality endorses the idea of co-benefits that are considered crucial to trigger transformative processes. This work concludes that the linkage of peri-urban farmland with the green infrastructure concept is a promising action field for the development of new pathways for urban transformation towards sustainable urban development. Along with these outcomes, attention is drawn to limitations that remain to be addressed by future research, especially the identification of further mechanisms required to support policy integration at all levels.},
  language  = {en}
}
@phdthesis{Rothe2020,
  author    = {Rothe, Viktoria},
  title     = {Das Yamabe-Problem auf global-hyperbolischen Lorentz-Mannigfaltigkeiten},
  doi       = {10.25932/publishup-48601},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-486012},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 65},
  year      = {2020},
  abstract  = {Im Jahre 1960 behauptete Yamabe folgende Aussage bewiesen zu haben: Auf jeder kompakten Riemannschen Mannigfaltigkeit (M,g) der Dimension n ≥ 3 existiert eine zu g konform {\"a}quivalente Metrik mit konstanter Skalarkr{\"u}mmung. Diese Aussage ist {\"a}quivalent zur Existenz einer L{\"o}sung einer bestimmten semilinearen elliptischen Differentialgleichung, der Yamabe-Gleichung. 1968 fand Trudinger einen Fehler in seinem Beweis und infolgedessen besch{\"a}ftigten sich viele Mathematiker mit diesem nach Yamabe benannten Yamabe-Problem. In den 80er Jahren konnte durch die Arbeiten von Trudinger, Aubin und Schoen gezeigt werden, dass diese Aussage tats{\"a}chlich zutrifft. Dadurch ergeben sich viele Vorteile, z.B. kann beim Analysieren von konform invarianten partiellen Differentialgleichungen auf kompakten Riemannschen Mannigfaltigkeiten die Skalarkr{\"u}mmung als konstant vorausgesetzt werden. Es stellt sich nun die Frage, ob die entsprechende Aussage auch auf Lorentz-Mannigfaltigkeiten gilt. Das Lorentz'sche Yamabe Problem lautet somit: Existiert zu einer gegebenen r{\"a}umlich kompakten global-hyperbolischen Lorentz-Mannigfaltigkeit (M,g) eine zu g konform {\"a}quivalente Metrik mit konstanter Skalarkr{\"u}mmung? Das Ziel dieser Arbeit ist es, dieses Problem zu untersuchen. Bei der sich aus dieser Fragestellung ergebenden Yamabe-Gleichung handelt es sich um eine semilineare Wellengleichung, deren L{\"o}sung eine positive glatte Funktion ist und aus der sich der konforme Faktor ergibt. Um die f{\"u}r die Behandlung des Yamabe-Problems ben{\"o}tigten Grundlagen so allgemein wie m{\"o}glich zu halten, wird im ersten Teil dieser Arbeit die lokale Existenztheorie f{\"u}r beliebige semilineare Wellengleichungen f{\"u}r Schnitte auf Vektorb{\"u}ndeln im Rahmen eines Cauchy-Problems entwickelt. Hierzu wird der Umkehrsatz f{\"u}r Banachr{\"a}ume angewendet, um mithilfe von bereits existierenden Existenzergebnissen zu linearen Wellengleichungen, Existenzaussagen zu semilinearen Wellengleichungen machen zu k{\"o}nnen. Es wird bewiesen, dass, falls die Nichtlinearit{\"a}t bestimmte Bedingungen erf{\"u}llt, eine fast zeitglobale L{\"o}sung des Cauchy-Problems f{\"u}r kleine Anfangsdaten sowie eine zeitlokale L{\"o}sung f{\"u}r beliebige Anfangsdaten existiert. Der zweite Teil der Arbeit befasst sich mit der Yamabe-Gleichung auf global-hyperbolischen Lorentz-Mannigfaltigkeiten. Zuerst wird gezeigt, dass die Nichtlinearit{\"a}t der Yamabe-Gleichung die geforderten Bedingungen aus dem ersten Teil erf{\"u}llt, so dass, falls die Skalarkr{\"u}mmung der gegebenen Metrik nahe an einer Konstanten liegt, kleine Anfangsdaten existieren, so dass die Yamabe-Gleichung eine fast zeitglobale L{\"o}sung besitzt. Mithilfe von Energieabsch{\"a}tzungen wird anschließend f{\"u}r 4-dimensionale global-hyperbolische Lorentz-Mannigfaltigkeiten gezeigt, dass unter der Annahme, dass die konstante Skalarkr{\"u}mmung der konform {\"a}quivalenten Metrik nichtpositiv ist, eine zeitglobale L{\"o}sung der Yamabe-Gleichung existiert, die allerdings nicht notwendigerweise positiv ist. Außerdem wird gezeigt, dass, falls die H2-Norm der Skalarkr{\"u}mmung bez{\"u}glich der gegebenen Metrik auf einem kompakten Zeitintervall auf eine bestimmte Weise beschr{\"a}nkt ist, die L{\"o}sung positiv auf diesem Zeitintervall ist. Hierbei wird ebenfalls angenommen, dass die konstante Skalarkr{\"u}mmung der konform {\"a}quivalenten Metrik nichtpositiv ist. Falls zus{\"a}tzlich hierzu gilt, dass die Skalarkr{\"u}mmung bez{\"u}glich der gegebenen Metrik negativ ist und die Metrik gewisse Bedingungen erf{\"u}llt, dann ist die L{\"o}sung f{\"u}r alle Zeiten in einem kompakten Zeitintervall positiv, auf dem der Gradient der Skalarkr{\"u}mmung auf eine bestimmte Weise beschr{\"a}nkt ist. In beiden F{\"a}llen folgt unter den angef{\"u}hrten Bedingungen die Existenz einer zeitglobalen positiven L{\"o}sung, falls M = I x Σ f{\"u}r ein beschr{\"a}nktes offenes Intervall I ist. Zum Schluss wird f{\"u}r M = R x Σ ein Beispiel f{\"u}r die Nichtexistenz einer globalen positiven L{\"o}sung angef{\"u}hrt.},
  language  = {de}
}
@phdthesis{Schill2020,
  author    = {Schill, Denisa},
  title     = {Employer Branding in der Gesundheitswirtschaft},
  doi       = {10.25932/publishup-47333},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473330},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIV, 237},
  year      = {2020},
  abstract  = {Die Gesundheitswirtschaft in Deutschland steht vor zahlreichen Ver{\"a}nderungen in ihrem Umfeld. Dabei mangelt es der Krankenhauslandschaft an {\"a}rztlichem Personal. Es fehlt insbesondere an Arztstunden bei zugleich steigendem Bedarf an medizinischen Leistungen. Der demografische Wandel, Abwanderung ins Ausland (z. B. in die Schweiz) und Extrapolationen wie Feminisierung des Arztberufs und der Wertewandel respektive Generationenforschung beg{\"u}nstigen diese Entwicklung. Zudem wird der Arbeitsplatz Krankenhaus zunehmend als unattraktiv von zuk{\"u}nftigen Arbeitnehmerkohorten angesehen. Nachwuchs{\"a}rzte entscheiden sich bereits im Studium vermehrt gegen die kurative Medizin beziehungsweise gegen eine medizinisch-klinische T{\"a}tigkeit. Ein virulentes Beschaffungsproblem zeichnet sich ab, das es zu l{\"o}sen gilt. Das Forschungsziel ist die Entwicklung eines ganzheitlichen strategischen L{\"o}sungsansatzes mit marktorientierter Akzentuierung f{\"u}r den Arbeitgeber Krankenhaus. Dabei wird das Krankenhaus als wissens- und kompetenzintensive Dienstleistungsorganisation definiert. Employer Branding stellt den Bezugsrahmen eines marktorientierten Personalmanagements dar. Ein forschungstheoretischer Unterbau wird durch strategische Managementans{\"a}tze integriert. Employer Branding schl{\"a}gt die Br{\"u}cke vom Market-based View zum Competence-based View und ist Markenmanagement im Kontext des strategischen Personalmanagements. In der vorliegenden Arbeit wird ein holistischer Bezugsrahmen vorgestellt, der die Wirkungszusammenh{\"a}nge respektive Employer Branding darstellt. Das Herzst{\"u}ck ist die Employer Value Proposition, die auf der Markenidentit{\"a}t der Organisation basiert. Ziel des Employer Branding Ansatzes ist es, unter anderem eine pr{\"a}ferenzerzeugende Wirkung im Prozess der Arbeitsplatzwahl sicherzustellen. Die Zielrichtung und die Erkenntnis-Interessen erfordern einen breit angelegten Forschungsansatz, der qualitative und quantitative Methoden kombiniert. Ziel der leitfadengesteuerten Tiefeninterviews (exploratives Studiendesign) ist es, bestehende und noch zu entwickelnde Kompetenzst{\"a}rken der Krankenhausorganisationen zu identifizieren. Bei der Stichprobe handelt es sich um ein „Typical Case Sampling" (N=12). Defizit{\"a}re Befunde, welche Werte und Attraktivit{\"a}tsfaktoren bei angehenden {\"A}rzten ausgepr{\"a}gt sind, werden best{\"a}tigt. In der Krankenhauslandschaft wird eine fragmentarische und reaktive Herangehensweise identifiziert, die die erfolgreiche Rekrutierung von qualifiziertem Krankenhauspersonal erschwert. Durch die qualitative Marktforschung werden Anforderungen des Marktes - also zuk{\"u}nftiges, {\"a}rztliches Krankenhauspersonal - auf faktorenanalytischer Basis analysiert. Die Stichprobe (N=475) ist isomorph. Dabei wird der Prozess der Einstellungsbildung in das neobehavioristische Erkl{\"a}rungsmodell des K{\"a}uferverhaltens eingeordnet. Die Vereinbarkeit von Beruf, Karriere und Familie sowie die betriebliche Kinderbetreuung werden als Schl{\"u}sselkomponenten erkannt. Wichtigste Arbeitswerte in Bezug auf einen attraktiven Arbeitgeber sind Verl{\"a}sslichkeit, Verantwortung und Respekt. Diese Komponenten haben kommunikativen Nutzen und Differenzierungskraft. Schließlich bewerten Bewerber ein Krankenhaus positiver im Prozess der Arbeitsplatzwahl, je mehr die Werte des potentiellen Arbeitnehmers mit dem Werteprofil der Person {\"u}bereinstimmen (Person-Organisation Fit). Krankenhausorganisationen, die den Employer Branding Ansatz implementieren und als Chance zur Definition ihrer St{\"a}rken, ihrer Vorz{\"u}ge und ihres Leistungsangebots als Arbeitgeber annehmen, r{\"u}sten sich f{\"u}r das verst{\"a}rkte Werben um Jungmediziner. Schließlich setzt Employer Branding als marktorientierter Strategieansatz intern und extern Kr{\"a}fte frei, die Differenzierungsvorteile gegen{\"u}ber anderen Arbeitgebern bringen. Dabei hat Employer Branding positive Auswirkungen auf den Human Ressource-Bereich entlang der Wertsch{\"o}pfungskette und mindert das gesamtwirtschaftliche Problem.},
  language  = {de}
}
@phdthesis{Schinkoeth2020,
  author    = {Schink{\"o}th, Michaela},
  title     = {Automatic affective reactions to exercise-related stimuli},
  doi       = {10.25932/publishup-47111},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471115},
  school      = {Universit{\"a}t Potsdam},
  pages     = {II, 117},
  year      = {2020},
  abstract  = {Even though the majority of individuals know that exercising is healthy, a high percentage struggle to achieve the recommended amount of exercise. The (social-cognitive) theories that are commonly applied to explain exercise motivation refer to the assumption that people base their decisions mainly on rational reasoning. However, behavior is not only bound to reflection. In recent years, the role of automaticity and affect for exercise motivation has been increasingly discussed. In this dissertation, central assumptions of the affective-reflective theory of physical inactivity and exercise (ART; Brand \& Ekkekakis, 2018), an exercise-specific dual-process theory that emphasizes the role of a momentary automatic affective reaction for exercise-decisions, were examined. The central aim of this dissertation was to investigate exercisers and non-exercisers automatic affective reactions to exercise-related stimuli (i.e., type-1 process). In particular, the two components of the ART's type-1 process, that are, automatic associations with exercise and the automatic affective valuation to exercise, were under study. In the first publication (Schinkoeth \& Antoniewicz, 2017), research on automatic (evaluative) associations with exercise was summarized and evaluated in a systematic review. The results indicated that automatic associations with exercise appeared to be relevant predictors for exercise behavior and other exercise-related variables, providing evidence for a central assumption of the ART's type-1 process. Furthermore, indirect methods seem to be suitable to assess automatic associations. The aim of the second publication (Schinkoeth, Weymar, \& Brand, 2019) was to approach the somato-affective core of the automatic valuation of exercise using analysis of reactivity in vagal HRV while viewing exercise-related pictures. Results revealed that differences in exercise volume could be regressed on HRV reactivity. In light of the ART, these findings were interpreted as evidence of an inter-individual affective reaction elicited at the thought of exercise and triggered by exercise-stimuli. In the third publication (Schinkoeth \& Brand, 2019, subm.), it was sought to disentangle and relate to each other the ART's type-1 process components—automatic associations and the affective valuation of exercise. Automatic associations to exercise were assessed with a recoding-free variant of an implicit association test (IAT). Analysis of HRV reactivity was applied to approach a somatic component of the affective valuation, and facial reactions in a facial expression (FE) task served as indicators of the automatic affective reaction's valence. Exercise behavior was assessed via self-report. The measurement of the affective valuation's valence with the FE task did not work well in this study. HRV reactivity was predicted by the IAT score and did also statistically predict exercise behavior. These results thus confirm and expand upon the results of publication two and provide empirical evidence for the type-1 process, as defined in the ART. This dissertation advances the field of exercise psychology concerning the influence of automaticity and affect on exercise motivation. Moreover, both methodical implications and theoretical extensions for the ART can be derived from the results.},
  language  = {en}
}
@phdthesis{Schuck2020,
  author    = {Schuck, Bernhard},
  title     = {Geomechanical and petrological characterisation of exposed slip zones, Alpine Fault, New Zealand},
  doi       = {10.25932/publishup-44612},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-446129},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XVII, 143},
  year      = {2020},
  abstract  = {The Alpine Fault is a large, plate-bounding, strike-slip fault extending along the north-western edge of the Southern Alps, South Island, New Zealand. It regularly accommodates large (MW > 8) earthquakes and has a high statistical probability of failure in the near future, i.e., is late in its seismic cycle. This pending earthquake and associated co-seismic landslides are expected to cause severe infrastructural damage that would affect thousands of people, so it presents a substantial geohazard. The interdisciplinary study presented here aims to characterise the fault zone's 4D (space and time) architecture, because this provides information about its rheological properties that will enable better assessment of the hazard the fault poses. The studies undertaken include field investigations of principal slip zone fault gouges exposed along strike of the fault, and subsequent laboratory analyses of these outcrop and additional borehole samples. These observations have provided new information on (I) characteristic microstructures down to the nanoscale that indicate which deformation mechanisms operated within the rocks, (II) mineralogical information that constrains the fault's geomechanical behaviour and (III) geochemical compositional information that allows the influence of fluid- related alteration processes on material properties to be unraveled. Results show that along-strike variations of fault rock properties such as microstructures and mineralogical composition are minor and / or do not substantially influence fault zone architecture. They furthermore provide evidence that the architecture of the fault zone, particularly its fault core, is more complex than previously considered, and also more complex than expected for this sort of mature fault cutting quartzofeldspathic rocks. In particular our results strongly suggest that the fault has more than one principal slip zone, and that these form an anastomosing network extending into the basement below the cover of Quaternary sediments. The observations detailed in this thesis highlight that two major processes, (I) cataclasis and (II) authigenic mineral formation, are the major controls on the rheology of the Alpine Fault. The velocity-weakening behaviour of its fault gouge is favoured by abundant nanoparticles promoting powder lubrication and grain rolling rather than frictional sliding. Wall-rock fragmentation is accompanied by co-seismic, fluid-assisted dilatancy that is recorded by calcite cementation. This mineralisation, along with authigenic formation of phyllosilicates, quickly alters the petrophysical fault zone properties after each rupture, restoring fault competency. Dense networks of anastomosing and mutually cross-cutting calcite veins and intensively reworked gouge matrix demonstrate that strain repeatedly localised within the narrow fault gouge. Abundantly undeformed euhedral chlorite crystallites and calcite veins cross-cutting both fault gouge and gravels that overlie basement on the fault's footwall provide evidence that the processes of authigenic phyllosilicate growth, fluid-assisted dilatancy and associated fault healing are processes active particularly close to the Earth's surface in this fault zone. Exposed Alpine Fault rocks are subject to intense weathering as direct consequence of abundant orogenic rainfall associated with the fault's location at the base of the Southern Alps. Furthermore, fault rock rheology is substantially affected by shallow-depth conditions such as the juxtaposition of competent hanging wall fault rocks on poorly consolidated footwall sediments. This means microstructural, mineralogical and geochemical properties of the exposed fault rocks may differ substantially from those at deeper levels, and thus are not characteristic of the majority of the fault rocks' history. Examples are (I) frictionally weak smectites found within the fault gouges being artefacts formed at temperature conditions, and imparting petrophysical properties that are not typical for most of fault rocks of the Alpine Fault, (II) grain-scale dissolution resulting from subaerial weathering rather than deformation by pressure-solution processes and (III) fault gouge geometries being more complex than expected for deeper counterparts. The methodological approaches deployed in analyses of this, and other fault zones, and the major results of this study are finally discussed in order to contextualize slip zone investigations of fault zones and landslides. Like faults, landslides are major geohazards, which highlights the importance of characterising their geomechanical properties. Similarities between faults, especially those exposed to subaerial processes, and landslides, include mineralogical composition and geomechanical behaviour. Together, this ensures failure occurs predominantly by cataclastic processes, although aseismic creep promoted by weak phyllosilicates is not uncommon. Consequently, the multidisciplinary approach commonly used to investigate fault zones may contribute to increase the understanding of landslide faulting processes and the assessment of their hazard potential.},
  language  = {en}
}
@phdthesis{SchulzBehrendt2020,
  author    = {Schulz-Behrendt, Claudia},
  title     = {Entwicklung und Evaluation eines berufsorientierten Gruppenprogramms Sozialer Arbeit in der medizinischen Rehabilitation am Beispiel kardiovaskul{\"a}rer Erkrankungen},
  doi       = {10.25932/publishup-49139},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-491397},
  school      = {Universit{\"a}t Potsdam},
  pages     = {142},
  year      = {2020},
  abstract  = {Die vorliegende Untersuchung analysierte den direkten Zusammenhang eines berufsbezogenen Angebots Sozialer Gruppenarbeit mit dem Ergebnis beruflicher Wiedereingliederung bei Rehabilitandinnen und Rehabilitanden in besonderen beruflichen Problemlagen. Sie wurde von der Deutschen Rentenversicherung Bund als Forschungsprojekt vom 01.01.2013 bis 31.12. 2015 gef{\"o}rdert und an der Professur f{\"u}r Rehabilitationswissenschaften der Universit{\"a}t Potsdam realisiert. Die Forschungsfrage lautete: Kann eine intensive sozialarbeiterische Gruppenintervention im Rahmen der station{\"a}ren medizinischen Rehabilitation soweit auf die St{\"a}rkung sozialer Kompetenzen und die Soziale Unterst{\"u}tzung von Rehabilitandinnen und Rehabilitanden einwirken, dass sich dadurch langfristige Verbesserungen hinsichtlich der beruflichen Wiedereingliederung im Vergleich zur konventionellen Behandlung ergeben? Die Studie gliederte sich in eine qualitative und eine quantitative Erhebung mit einer zwischenliegenden Intervention. Eingeschlossen waren 352 Patientinnen und Patienten im Alter zwischen 18 und 65 Jahren mit kardiovaskul{\"a}ren Diagnosen, deren Krankheitsbilder h{\"a}ufig von komplexen Problemlagen begleitet sind, verbunden mit einer schlechten sozialmedizinischen Prognose. Die Evaluation der Gruppenintervention erfolgte in einem clusterrandomisierten kontrollierten Studiendesign, um einen empirischen Nachweis dar{\"u}ber zu erbringen, inwieweit die Intervention gegen{\"u}ber der regul{\"a}ren sozialarbeiterischen Behandlung h{\"o}here Effekte erzielen kann. Die Interventionsgruppen nahmen am Gruppenprogramm teil, die Kontrollgruppen erhielten die regul{\"a}re sozialarbeiterische Behandlung. Im Ergebnis konnte mit dieser Stichprobe kein Nachweis zur Verbesserung der beruflichen Wiedereingliederung, der gesundheitsbezogenen Arbeitsf{\"a}higkeit, der Lebensqualit{\"a}t sowie der Sozialen Unterst{\"u}tzung durch die Teilnahme am sozialarbeiterischen Gruppenprogramm erbracht werden. Die Return-To-Work-Rate betrug 43,7 \%, ein Viertel der Untersuchungsgruppe befand sich nach einem Jahr in Arbeitslosigkeit. Die durchgef{\"u}hrte Gruppenintervention ist dem konventionellen Setting Sozialer Arbeit als gleichwertig anzusehen. Schlussfolgernd wurde auf eine sozialarbeiterische Unterst{\"u}tzung der beruflichen Wiedereingliederung {\"u}ber einen l{\"a}ngeren Zeitraum nach einer kardiovaskul{\"a}ren Erkrankung verwiesen, insbesondere durch wohnortnahe Angebote zu einem sp{\"a}teren Zeitpunkt bei stabilerer Gesundheit. Aus den Erhebungen ließen sich m{\"o}gliche Erfolge bei engerer Kooperation zwischen dem Fachbereich der Sozialen Arbeit und der Psychologie ableiten. Ebenfalls gab es Hinweise auf die einflussreiche Rolle der Angeh{\"o}rigen, die durch Einbindung in die Soziale Beratung unterst{\"u}tzend auf den Wiedereingliederungsprozess wirken k{\"o}nnten. Die Passgenauigkeit der untersuchten sozialarbeiterischen Gruppeninterventionen ist durch eine gezielte Soziale Diagnostik zu verbessern.},
  language  = {de}
}
@phdthesis{Schuster2020,
  author    = {Schuster, Maja},
  title     = {High resolution decoding of the tobacco chloroplast translatome and its dynamics during light-intensity acclimation},
  doi       = {10.25932/publishup-51268},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-512680},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvii, 155},
  year      = {2020},
  abstract  = {Chloroplasts are the photosynthetic organelles in plant and algae cells that enable photoautotrophic growth. Due to their prokaryotic origin, modern-day chloroplast genomes harbor 100 to 200 genes. These genes encode for core components of the photosynthetic complexes and the chloroplast gene expression machinery, making most of them essential for the viability of the organism. The regulation of those genes is predominated by translational adjustments. The powerful technique of ribosome profiling was successfully used to generate highly resolved pictures of the translational landscape of Arabidopsis thaliana cytosol, identifying translation of upstream open reading frames and long non-coding transcripts. In addition, differences in plastidial translation and ribosomal pausing sites were addressed with this method. However, a highly resolved picture of the chloroplast translatome is missing. Here, with the use of chloroplast isolation and targeted ribosome affinity purification, I generated highly enriched ribosome profiling datasets of the chloroplasts translatome for Nicotiana tabacum in the dark and light. Chloroplast isolation was found unsuitable for the unbiased analysis of translation in the chloroplast but adequate to identify potential co-translational import. Affinity purification was performed for the small and large ribosomal subunit independently. The enriched datasets mirrored the results obtained from whole-cell ribosome profiling. Enhanced translational activity was detected for psbA in the light. An alternative translation initiation mechanism was not identified by selective enrichment of small ribosomal subunit footprints. In sum, this is the first study that used enrichment strategies to obtain high-depth ribosome profiling datasets of chloroplasts to study ribosome subunit distribution and chloroplast associated translation. Ever-changing light intensities are challenging the photosynthetic capacity of photosynthetic organism. Increased light intensities may lead to over-excitation of photosynthetic reaction centers resulting in damage of the photosystem core subunits. Additional to an expensive repair mechanism for the photosystem II core protein D1, photosynthetic organisms developed various features to reduce or prevent photodamage. In the long-term, photosynthetic complex contents are adjusted for the efficient use of experienced irradiation. However, the contribution of chloroplastic gene expression in the acclimation process remained largely unknown. Here, comparative transcriptome and ribosome profiling was performed for the early time points of high-light acclimation in Nicotiana tabacum chloroplasts in a genome-wide scale. The time- course data revealed stable transcript level and only minor changes in translational activity of specific chloroplast genes during high-light acclimation. Yet, psbA translation was increased by two-fold in the high light from shortly after the shift until the end of the experiment. A stress-inducing shift from low- to high light exhibited increased translation only of psbA. This study indicate that acclimation fails to start in the observed time frame and only short-term responses to reduce photoinhibition were observed.},
  language  = {en}
}
@phdthesis{Schuetze2020,
  author    = {Sch{\"u}tze, Franziska},
  title     = {Finance for a sustainable economy},
  doi       = {10.25932/publishup-48441},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-484415},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xi, 128},
  year      = {2020},
  abstract  = {With his September 2015 speech "Breaking the tragedy of the horizon", the President of the Central Bank of England, Mark Carney, put climate change on the agenda of financial market regulators. Until then, climate change had been framed mainly as a problem of negative externalities leading to long-term economic costs, which resulted in countries trying to keep the short-term costs of climate action to a minimum. Carney argued that climate change, as well as climate policy, can also lead to short-term financial risks, potentially causing strong adjustments in asset prices. Analysing the effect of a sustainability transition on the financial sector challenges traditional economic and financial analysis and requires a much deeper understanding of the interrelations between climate policy and financial markets. This dissertation thus investigates the implications of climate policy for financial markets as well as the role of financial markets in a transition to a sustainable economy. The approach combines insights from macroeconomic and financial risk analysis. Following an introduction and classification in Chapter 1, Chapter 2 shows a macroeconomic analysis that combines ambitious climate targets (negative externality) with technological innovation (positive externality), adaptive expectations and an investment program, resulting in overall positive macroeconomic outcomes. The analysis also reveals the limitations of climate economic models in their representation of financial markets. Therefore, the subsequent part of this dissertation is concerned with the link between climate policies and financial markets. In Chapter 3, an empirical analysis of stock-market responses to the announcement of climate policy targets is performed to investigate impacts of climate policy on financial markets. Results show that 1) international climate negotiations have an effect on asset prices and 2) investors increasingly recognize transition risks in carbon-intensive investments. In Chapter 4, an analysis of equity markets and the interbank market shows that transition risks can potentially affect a large part of the equity market and that financial interconnections can amplify negative shocks. In Chapter 5, an analysis of mortgage loans shows how information on climate policy and the energy performance of buildings can be integrated into risk management and reflected in interest rates. While costs of climate action have been explored at great depth, this dissertation offers two main contributions. First, it highlights the importance of a green investment program to strengthen the macroeconomic benefits of climate action. Second, it shows different approaches on how to integrate transition risks and opportunities into financial market analysis. Anticipating potential losses and gains in the value of financial assets as early as possible can make the financial system more resilient to transition risks and can stimulate investments into the decarbonization of the economy.},
  language  = {en}
}
@phdthesis{Seebeck2020,
  author    = {Seebeck, Nicole},
  title     = {Regulation of the organokines FGF21 and chemerin by diet},
  doi       = {10.25932/publishup-47114},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471140},
  school      = {Universit{\"a}t Potsdam},
  pages     = {i, 132},
  year      = {2020},
  abstract  = {The hepatokine FGF21 and the adipokine chemerin have been implicated as metabolic regulators and mediators of inter-tissue crosstalk. While FGF21 is associated with beneficial metabolic effects and is currently being tested as an emerging therapeutic for obesity and diabetes, chemerin is linked to inflammation-mediated insulin resistance. However, dietary regulation of both organokines and their role in tissue interaction needs further investigation. The LEMBAS nutritional intervention study investigated the effects of two diets differing in their protein content in obese human subjects with non-alcoholic fatty liver disease (NAFLD). The study participants consumed hypocaloric diets containing either low (LP: 10 EN\%, n = 10) or high (HP: 30 EN\%, n = 9) dietary protein 3 weeks prior to bariatric surgery. Before and after the intervention the participants were anthropometrically assessed, blood samples were drawn, and hepatic fat content was determined by MRS. During bariatric surgery, paired subcutaneous and visceral adipose tissue biopsies as well as liver biopsies were collected. The aim of this thesis was to investigate circulating levels and tissue-specific regulation of (1) FGF21 and (2) chemerin in the LEMBAS cohort. The results were compared to data obtained in 92 metabolically healthy subjects with normal glucose tolerance and normal liver fat content. (1) Serum FGF21 concentrations were elevated in the obese subjects, and strongly associated with intrahepatic lipids (IHL). In accordance, FGF21 serum concentrations increased with severity of NAFLD as determined histologically in the liver biopsies. Though both diets were successful in reducing IHL, the effect was more pronounced in the HP group. FGF21 serum concentrations and mRNA expression were bi-directionally regulated by dietary protein, independent from metabolic improvements. In accordance, in the healthy study subjects, serum FGF21 concentrations dropped by more than 60\% in response to the HP diet. A short-term HP intervention confirmed the acute downregulation of FGF21 within 24 hours. Lastly, experiments in HepG2 cell cultures and primary murine hepatocytes identified nitrogen metabolites (NH4Cl and glutamine) to dose-dependently suppress FGF21 expression. (2) Circulating chemerin concentrations were considerably elevated in the obese versus lean study participants and differently associated with markers of obesity and NAFLD in the two cohorts. The adipokine decreased in response to the hypocaloric interventions while an unhealthy high-fat diet induced a rise in chemerin serum levels. In the lean subjects, mRNA expression of RARRES2, encoding chemerin, was strongly and positively correlated with expression of several cytokines, including MCP1, TNFα, and IL6, as well as markers of macrophage infiltration in the subcutaneous fat depot. However, RARRES2 was not associated with any cytokine assessed in the obese subjects and the data indicated an involvement of chemerin not only in the onset but also resolution of inflammation. Analyses of the tissue biopsies and experiments in human primary adipocytes point towards a role of chemerin in adipogenesis while discrepancies between the in vivo and in vitro data were detected. Taken together, the results of this thesis demonstrate that circulating FGF21 and chemerin levels are considerably elevated in obesity and responsive to dietary interventions. FGF21 was acutely and bi-directionally regulated by dietary protein in a hepatocyte-autonomous manner. Given that both, a lack in essential amino acids and excessive nitrogen intake, exert metabolic stress, FGF21 may serve as an endocrine signal for dietary protein balance. Lastly, the data revealed that chemerin is derailed in obesity and associated with obesity-related inflammation. However, future studies on chemerin should consider functional and regulatory differences between secreted and tissue-specific isoforms.},
  language  = {en}
}
@phdthesis{Senftleben2020,
  author    = {Senftleben, Robin},
  title     = {Earth's magnetic field over the last 1000 years},
  doi       = {10.25932/publishup-47315},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473150},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xii, 104},
  year      = {2020},
  abstract  = {To investigate the reliability and stability of spherical harmonic models based on archeo/-paleomagnetic data, 2000 Geomagnetic models were calculated. All models are based on the same data set but with randomized uncertainties. Comparison of these models to the geomagnetic field model gufm1 showed that large scale magnetic field structures up to spherical harmonic degree 4 are stable throughout all models. Through a ranking of all models by comparing the dipole coefficients to gufm1 more realistic uncertainty estimates were derived than the authors of the data provide. The derived uncertainty estimates were used in further modelling, which combines archeo/-paleomagnetic and historical data. The huge difference in data count, accuracy and coverage of these two very different data sources made it necessary to introduce a time dependent spatial damping, which was constructed to constrain the spatial complexity of the model. Finally 501 models were calculated by considering that each data point is a Gaussian random variable, whose mean is the original value and whose standard deviation is its uncertainty. The final model arhimag1k is calculated by taking the mean of the 501 sets of Gauss coefficients. arhimag1k fits different dependent and independent data sets well. It shows an early reverse flux patch at the core-mantle boundary between 1000 AD and 1200 AD at the location of the South Atlantic Anomaly today. Another interesting feature is a high latitude flux patch over Greenland between 1200 and 1400 AD. The dipole moment shows a constant behaviour between 1600 and 1840 AD. In the second part of the thesis 4 new paleointensities from 4 different flows of the island Fogo, which is part of Cape Verde, are presented. The data is fitted well by arhimag1k with the exception of the value at 1663 of 28.3 microtesla, which is approximately 10 microtesla lower than the model suggest.},
  language  = {en}
}
@phdthesis{Shaabani2020,
  author    = {Shaabani, Nuhad},
  title     = {On discovering and incrementally updating inclusion dependencies},
  doi       = {10.25932/publishup-47186},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-471862},
  school      = {Universit{\"a}t Potsdam},
  pages     = {119},
  year      = {2020},
  abstract  = {In today's world, many applications produce large amounts of data at an enormous rate. Analyzing such datasets for metadata is indispensable for effectively understanding, storing, querying, manipulating, and mining them. Metadata summarizes technical properties of a dataset which rang from basic statistics to complex structures describing data dependencies. One type of dependencies is inclusion dependency (IND), which expresses subset-relationships between attributes of datasets. Therefore, inclusion dependencies are important for many data management applications in terms of data integration, query optimization, schema redesign, or integrity checking. So, the discovery of inclusion dependencies in unknown or legacy datasets is at the core of any data profiling effort. For exhaustively detecting all INDs in large datasets, we developed S-indd++, a new algorithm that eliminates the shortcomings of existing IND-detection algorithms and significantly outperforms them. S-indd++ is based on a novel concept for the attribute clustering for efficiently deriving INDs. Inferring INDs from our attribute clustering eliminates all redundant operations caused by other algorithms. S-indd++ is also based on a novel partitioning strategy that enables discording a large number of candidates in early phases of the discovering process. Moreover, S-indd++ does not require to fit a partition into the main memory--this is a highly appreciable property in the face of ever-growing datasets. S-indd++ reduces up to 50\% of the runtime of the state-of-the-art approach. None of the approach for discovering INDs is appropriate for the application on dynamic datasets; they can not update the INDs after an update of the dataset without reprocessing it entirely. To this end, we developed the first approach for incrementally updating INDs in frequently changing datasets. We achieved that by reducing the problem of incrementally updating INDs to the incrementally updating the attribute clustering from which all INDs are efficiently derivable. We realized the update of the clusters by designing new operations to be applied to the clusters after every data update. The incremental update of INDs reduces the time of the complete rediscovery by up to 99.999\%. All existing algorithms for discovering n-ary INDs are based on the principle of candidate generation--they generate candidates and test their validity in the given data instance. The major disadvantage of this technique is the exponentially growing number of database accesses in terms of SQL queries required for validation. We devised Mind2, the first approach for discovering n-ary INDs without candidate generation. Mind2 is based on a new mathematical framework developed in this thesis for computing the maximum INDs from which all other n-ary INDs are derivable. The experiments showed that Mind2 is significantly more scalable and effective than hypergraph-based algorithms.},
  language  = {en}
}
@phdthesis{Sianipar2020,
  author    = {Sianipar, Johannes Harungguan},
  title     = {Towards scalable and secure virtual laboratory for cybersecurity e-learning},
  doi       = {10.25932/publishup-50279},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-502793},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xviii, 156},
  year      = {2020},
  abstract  = {Distance Education or e-Learning platform should be able to provide a virtual laboratory to let the participants have hands-on exercise experiences in practicing their skill remotely. Especially in Cybersecurity e-Learning where the participants need to be able to attack or defend the IT System. To have a hands-on exercise, the virtual laboratory environment must be similar to the real operational environment, where an attack or a victim is represented by a node in a virtual laboratory environment. A node is usually represented by a Virtual Machine (VM). Scalability has become a primary issue in the virtual laboratory for cybersecurity e-Learning because a VM needs a significant and fix allocation of resources. Available resources limit the number of simultaneous users. Scalability can be increased by increasing the efficiency of using available resources and by providing more resources. Increasing scalability means increasing the number of simultaneous users. In this thesis, we propose two approaches to increase the efficiency of using the available resources. The first approach in increasing efficiency is by replacing virtual machines (VMs) with containers whenever it is possible. The second approach is sharing the load with the user-on-premise machine, where the user-on-premise machine represents one of the nodes in a virtual laboratory scenario. We also propose two approaches in providing more resources. One way to provide more resources is by using public cloud services. Another way to provide more resources is by gathering resources from the crowd, which is referred to as Crowdresourcing Virtual Laboratory (CRVL). In CRVL, the crowd can contribute their unused resources in the form of a VM, a bare metal system, an account in a public cloud, a private cloud and an isolated group of VMs, but in this thesis, we focus on a VM. The contributor must give the credential of the VM admin or root user to the CRVL system. We propose an architecture and methods to integrate or dis-integrate VMs from the CRVL system automatically. A Team placement algorithm must also be investigated to optimize the usage of resources and at the same time giving the best service to the user. Because the CRVL system does not manage the contributor host machine, the CRVL system must be able to make sure that the VM integration will not harm their system and that the training material will be stored securely in the contributor sides, so that no one is able to take the training material away without permission. We are investigating ways to handle this kind of threats. We propose three approaches to strengthen the VM from a malicious host admin. To verify the integrity of a VM before integration to the CRVL system, we propose a remote verification method without using any additional hardware such as the Trusted Platform Module chip. As the owner of the host machine, the host admins could have access to the VM's data via Random Access Memory (RAM) by doing live memory dumping, Spectre and Meltdown attacks. To make it harder for the malicious host admin in getting the sensitive data from RAM, we propose a method that continually moves sensitive data in RAM. We also propose a method to monitor the host machine by installing an agent on it. The agent monitors the hypervisor configurations and the host admin activities. To evaluate our approaches, we conduct extensive experiments with different settings. The use case in our approach is Tele-Lab, a Virtual Laboratory platform for Cyber Security e-Learning. We use this platform as a basis for designing and developing our approaches. The results show that our approaches are practical and provides enhanced security.},
  language  = {en}
}
@phdthesis{Siemiatkowska2020,
  author    = {Siemiatkowska, Beata},
  title     = {Redox signalling in plants},
  doi       = {10.25932/publishup-48911},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-489119},
  school      = {Universit{\"a}t Potsdam},
  pages     = {127},
  year      = {2020},
  abstract  = {Once proteins are synthesized, they can additionally be modified by post-translational modifications (PTMs). Proteins containing reactive cysteine thiols, stabilized in their deprotonated form due to their local environment as thiolates (RS-), serve as redox sensors by undergoing a multitude of oxidative PTMs (Ox-PTMs). Ox-PTMs such as S-nitrosylation or formation of inter- or intra-disulfide bridges induce functional changes in these proteins. Proteins containing cysteines, whose thiol oxidation state regulates their functions, belong to the so-called redoxome. Such Ox-PTMs are controlled by site-specific cellular events that play a crucial role in protein regulation, affecting enzyme catalytic sites, ligand binding affinity, protein-protein interactions or protein stability. Reversible protein thiol oxidation is an essential regulatory mechanism of photosynthesis, metabolism, and gene expression in all photosynthetic organisms. Therefore, studying PTMs will remain crucial for understanding plant adaptation to external stimuli like fluctuating light conditions. Optimizing methods suitable for studying plants Ox-PTMs is of high importance for elucidation of the redoxome in plants. This study focusses on thiol modifications occurring in plant and provides novel insight into in vivo redoxome of Arabidopsis thaliana in response to light vs. dark. This was achieved by utilizing a resin-assisted thiol enrichment approach. Furthermore, confirmation of candidates on the single protein level was carried out by a differential labelling approach. The thiols and disulfides were differentially labelled, and the protein levels were detected using immunoblot analysis. Further analysis was focused on light-reduced proteins. By the enrichment approach many well studied redox-regulated proteins were identified. Amongst those were fructose 1,6-bisphosphatase (FBPase) and sedoheptulose-1,7-bisphosphatase (SBPase) which have previously been described as thioredoxin system targeted enzymes. The redox regulated proteins identified in the current study were compared to several published, independent results showing redox regulated proteins in Arabidopsis leaves, root, mitochondria and specifically S-nitrosylated proteins. These proteins were excluded as potential new candidates but remain as a proof-of-concept to the enrichment experiments to be effective. Additionally, CSP41A and CSP41B proteins, which emerged from this study as potential targets of redox-regulation, were analyzed by Ribo-Seq. The active translatome study of csp41a mutant vs. wild-type showed most of the significant changes at end of the night, similarly as csp41b. Yet, in both mutants only several chloroplast-encoded genes were altered. Further studies of CSP41A and CSP41B proteins are needed to reveal their functions and elucidate the role of redox regulation of these proteins.},
  language  = {en}
}