@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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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{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} }