@phdthesis{AbdelwahabHusseinAbdelwahabElsayed2019,
  author    = {Abdelwahab Hussein Abdelwahab Elsayed, Ahmed},
  title     = {Probabilistic, deep, and metric learning for biometric identification from eye movements},
  doi       = {10.25932/publishup-46798},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-467980},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vi, 65},
  year      = {2019},
  abstract  = {A central insight from psychological studies on human eye movements is that eye movement patterns are highly individually characteristic. They can, therefore, be used as a biometric feature, that is, subjects can be identified based on their eye movements. This thesis introduces new machine learning methods to identify subjects based on their eye movements while viewing arbitrary content. The thesis focuses on probabilistic modeling of the problem, which has yielded the best results in the most recent literature. The thesis studies the problem in three phases by proposing a purely probabilistic, probabilistic deep learning, and probabilistic deep metric learning approach. In the first phase, the thesis studies models that rely on psychological concepts about eye movements. Recent literature illustrates that individual-specific distributions of gaze patterns can be used to accurately identify individuals. In these studies, models were based on a simple parametric family of distributions. Such simple parametric models can be robustly estimated from sparse data, but have limited flexibility to capture the differences between individuals. Therefore, this thesis proposes a semiparametric model of gaze patterns that is flexible yet robust for individual identification. These patterns can be understood as domain knowledge derived from psychological literature. Fixations and saccades are examples of simple gaze patterns. The proposed semiparametric densities are drawn under a Gaussian process prior centered at a simple parametric distribution. Thus, the model will stay close to the parametric class of densities if little data is available, but it can also deviate from this class if enough data is available, increasing the flexibility of the model. The proposed method is evaluated on a large-scale dataset, showing significant improvements over the state-of-the-art. Later, the thesis replaces the model based on gaze patterns derived from psychological concepts with a deep neural network that can learn more informative and complex patterns from raw eye movement data. As previous work has shown that the distribution of these patterns across a sequence is informative, a novel statistical aggregation layer called the quantile layer is introduced. It explicitly fits the distribution of deep patterns learned directly from the raw eye movement data. The proposed deep learning approach is end-to-end learnable, such that the deep model learns to extract informative, short local patterns while the quantile layer learns to approximate the distributions of these patterns. Quantile layers are a generic approach that can converge to standard pooling layers or have a more detailed description of the features being pooled, depending on the problem. The proposed model is evaluated in a large-scale study using the eye movements of subjects viewing arbitrary visual input. The model improves upon the standard pooling layers and other statistical aggregation layers proposed in the literature. It also improves upon the state-of-the-art eye movement biometrics by a wide margin. Finally, for the model to identify any subject — not just the set of subjects it is trained on — a metric learning approach is developed. Metric learning learns a distance function over instances. The metric learning model maps the instances into a metric space, where sequences of the same individual are close, and sequences of different individuals are further apart. This thesis introduces a deep metric learning approach with distributional embeddings. The approach represents sequences as a set of continuous distributions in a metric space; to achieve this, a new loss function based on Wasserstein distances is introduced. The proposed method is evaluated on multiple domains besides eye movement biometrics. This approach outperforms the state of the art in deep metric learning in several domains while also outperforming the state of the art in eye movement biometrics.},
  language  = {en}
}
@phdthesis{AlHalbouni2019,
  author    = {Al-Halbouni, Djamil},
  title     = {Photogrammetry and distinct element geomechanical modelling of sinkholes and large-scale karstic depressions},
  doi       = {10.25932/publishup-43215},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432159},
  school      = {Universit{\"a}t Potsdam},
  pages     = {137},
  year      = {2019},
  abstract  = {Sinkholes and depressions are typical landforms of karst regions. They pose a considerable natural hazard to infrastructure, agriculture, economy and human life in affected areas worldwide. The physio-chemical processes of sinkholes and depression formation are manifold, ranging from dissolution and material erosion in the subsurface to mechanical subsidence/failure of the overburden. This thesis addresses the mechanisms leading to the development of sinkholes and depressions by using complementary methods: remote sensing, distinct element modelling and near-surface geophysics. In the first part, detailed information about the (hydro)-geological background, ground structures, morphologies and spatio-temporal development of sinkholes and depressions at a very active karst area at the Dead Sea are derived from satellite image analysis, photogrammetry and geologic field surveys. There, clusters of an increasing number of sinkholes have been developing since the 1980s within large-scale depressions and are distributed over different kinds of surface materials: clayey mud, sandy-gravel alluvium and lacustrine evaporites (salt). The morphology of sinkholes differs depending in which material they form: Sinkholes in sandy-gravel alluvium and salt are generally deeper and narrower than sinkholes in the interbedded evaporite and mud deposits. From repeated aerial surveys, collapse precursory features like small-scale subsidence, individual holes and cracks are identified in all materials. The analysis sheds light on the ongoing hazardous subsidence process, which is driven by the base-level fall of the Dead Sea and by the dynamic formation of subsurface water channels. In the second part of this thesis, a novel, 2D distinct element geomechanical modelling approach with the software PFC2D-V5 to simulating individual and multiple cavity growth and sinkhole and large-scale depression development is presented. The approach involves a stepwise material removal technique in void spaces of arbitrarily shaped geometries and is benchmarked by analytical and boundary element method solutions for circular cavities. Simulated compression and tension tests are used to calibrate model parameters with bulk rock properties for the materials of the field site. The simulations show that cavity and sinkhole evolution is controlled by material strength of both overburden and cavity host material, the depth and relative speed of the cavity growth and the developed stress pattern in the subsurface. Major findings are: (1) A progressively deepening differential subrosion with variable growth speed yields a more fragmented stress pattern with stress interaction between the cavities. It favours multiple sinkhole collapses and nesting within large-scale depressions. (2) Low-strength materials do not support large cavities in the material removal zone, and subsidence is mainly characterised by gradual sagging into the material removal zone with synclinal bending. (3) High-strength materials support large cavity formation, leading to sinkhole formation by sudden collapse of the overburden. (4) Large-scale depression formation happens either by coalescence of collapsing holes, block-wise brittle failure, or gradual sagging and lateral widening. The distinct element based approach is compared to results from remote sensing and geophysics at the field site. The numerical simulation outcomes are generally in good agreement with derived morphometrics, documented surface and subsurface structures as well as seismic velocities. Complementary findings on the subrosion process are provided from electric and seismic measurements in the area. Based on the novel combination of methods in this thesis, a generic model of karst landform evolution with focus on sinkhole and depression formation is developed. A deepening subrosion system related to preferential flow paths evolves and creates void spaces and subsurface conduits. This subsequently leads to hazardous subsidence, and the formation of sinkholes within large-scale depressions. Finally, a monitoring system for shallow natural hazard phenomena consisting of geodetic and geophysical observations is proposed for similarly affected areas.},
  language  = {en}
}
@phdthesis{Amirkhanyan2019,
  author    = {Amirkhanyan, Aragats},
  title     = {Methods and frameworks for GeoSpatioTemporal data analytics},
  doi       = {10.25932/publishup-44168},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441685},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxiv, 133},
  year      = {2019},
  abstract  = {In the era of social networks, internet of things and location-based services, many online services produce a huge amount of data that have valuable objective information, such as geographic coordinates and date time. These characteristics (parameters) in the combination with a textual parameter bring the challenge for the discovery of geospatiotemporal knowledge. This challenge requires efficient methods for clustering and pattern mining in spatial, temporal and textual spaces. In this thesis, we address the challenge of providing methods and frameworks for geospatiotemporal data analytics. As an initial step, we address the challenges of geospatial data processing: data gathering, normalization, geolocation, and storage. That initial step is the basement to tackle the next challenge -- geospatial clustering challenge. The first step of this challenge is to design the method for online clustering of georeferenced data. This algorithm can be used as a server-side clustering algorithm for online maps that visualize massive georeferenced data. As the second step, we develop the extension of this method that considers, additionally, the temporal aspect of data. For that, we propose the density and intensity-based geospatiotemporal clustering algorithm with fixed distance and time radius. Each version of the clustering algorithm has its own use case that we show in the thesis. In the next chapter of the thesis, we look at the spatiotemporal analytics from the perspective of the sequential rule mining challenge. We design and implement the framework that transfers data into textual geospatiotemporal data - data that contain geographic coordinates, time and textual parameters. By this way, we address the challenge of applying pattern/rule mining algorithms in geospatiotemporal space. As the applicable use case study, we propose spatiotemporal crime analytics -- discovery spatiotemporal patterns of crimes in publicly available crime data. The second part of the thesis, we dedicate to the application part and use case studies. We design and implement the application that uses the proposed clustering algorithms to discover knowledge in data. Jointly with the application, we propose the use case studies for analysis of georeferenced data in terms of situational and public safety awareness.},
  language  = {en}
}
@phdthesis{Angwenyi2019,
  author    = {Angwenyi, David},
  title     = {Time-continuous state and parameter estimation with application to hyperbolic SPDEs},
  doi       = {10.25932/publishup-43654},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436542},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xi, 101},
  year      = {2019},
  abstract  = {Data assimilation has been an active area of research in recent years, owing to its wide utility. At the core of data assimilation are filtering, prediction, and smoothing procedures. Filtering entails incorporation of measurements' information into the model to gain more insight into a given state governed by a noisy state space model. Most natural laws are governed by time-continuous nonlinear models. For the most part, the knowledge available about a model is incomplete; and hence uncertainties are approximated by means of probabilities. Time-continuous filtering, therefore, holds promise for wider usefulness, for it offers a means of combining noisy measurements with imperfect model to provide more insight on a given state. The solution to time-continuous nonlinear Gaussian filtering problem is provided for by the Kushner-Stratonovich equation. Unfortunately, the Kushner-Stratonovich equation lacks a closed-form solution. Moreover, the numerical approximations based on Taylor expansion above third order are fraught with computational complications. For this reason, numerical methods based on Monte Carlo methods have been resorted to. Chief among these methods are sequential Monte-Carlo methods (or particle filters), for they allow for online assimilation of data. Particle filters are not without challenges: they suffer from particle degeneracy, sample impoverishment, and computational costs arising from resampling. The goal of this thesis is to:— i) Review the derivation of Kushner-Stratonovich equation from first principles and its extant numerical approximation methods, ii) Study the feedback particle filters as a way of avoiding resampling in particle filters, iii) Study joint state and parameter estimation in time-continuous settings, iv) Apply the notions studied to linear hyperbolic stochastic differential equations. The interconnection between It{\^o} integrals and stochastic partial differential equations and those of Stratonovich is introduced in anticipation of feedback particle filters. With these ideas and motivated by the variants of ensemble Kalman-Bucy filters founded on the structure of the innovation process, a feedback particle filter with randomly perturbed innovation is proposed. Moreover, feedback particle filters based on coupling of prediction and analysis measures are proposed. They register a better performance than the bootstrap particle filter at lower ensemble sizes. We study joint state and parameter estimation, both by means of extended state spaces and by use of dual filters. Feedback particle filters seem to perform well in both cases. Finally, we apply joint state and parameter estimation in the advection and wave equation, whose velocity is spatially varying. Two methods are employed: Metropolis Hastings with filter likelihood and a dual filter comprising of Kalman-Bucy filter and ensemble Kalman-Bucy filter. The former performs better than the latter.},
  language  = {en}
}
@phdthesis{AppiahDwomoh2019,
  author    = {Appiah-Dwomoh, Edem Korkor},
  title     = {Postural control and back pain in adolescent athletes},
  doi       = {10.25932/publishup-44269},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-442692},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VI, 77, X},
  year      = {2019},
  abstract  = {Back pain is a problem in adolescent athletes affecting postural control which is an important requirement for physical and daily activities whether under static or dynamic conditions. One leg stance and star excursion balance postural control tests are effective in measuring static and dynamic postural control respectively. These tests have been used in individuals with back pain, athletes and non-athletes without first establishing their reliabilities. In addition to this, there is no published literature investigating dynamic posture in adolescent athletes with back pain using the star excursion balance test. Therefore, the aim of the thesis was to assess deficit in postural control in adolescent athletes with and without back pain using static (one leg stance test) and dynamic postural (SEBT) control tests. Adolescent athletes with and without back pain participated in the study. Static and dynamic postural control tests were performed using one leg stance and SEBT respectively. The reproducibility of both tests was established. Afterwards, it was determined whether there was an association between static and dynamic posture using the measure of displacement of the centre pressure and reach distance respectively. Finally, it was investigated whether there was a difference in postural control in adolescent athletes with and without back pain using the one leg stance test and the SEBT. Fair to excellent reliabilities was recorded for the static (one leg stance) and dynamic (star excursion balance) postural control tests in the subjects of interest. No association was found between variables of the static and dynamic tests for the adolescent athletes with and without back pain. Also, no statistically significant difference was obtained between adolescent athletics with and without back pain using the static and dynamic postural control test. One leg stance test and SEBT can be used as measures of postural control in adolescent athletes with and without back pain. Although static and dynamic postural control might be related, adolescent athletes with and without back pain might be using different mechanisms in controlling their static and dynamic posture. Consequently, static and dynamic postural control in adolescent athletes with back pain was not different from those without back pain. These outcome measures might not be challenging enough to detect deficit in postural control in our study group of interest.},
  language  = {en}
}
@phdthesis{Aretz2019,
  author    = {Aretz, Sarah},
  title     = {Entwicklung und Evaluation eines Testinstruments zur Untersuchung von Vorkenntnissen und Pr{\"a}konzepten in der Kosmologie},
  doi       = {10.25932/publishup-42542},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-425421},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 133},
  year      = {2019},
  abstract  = {Kosmologie beschreibt die Entwicklung des Universums als Ganzes. Kosmologische Entdeckungen in Theorie und Praxis haben daher unser modernes wissenschaftliches Weltbild entscheidend ge­pr{\"a}gt. Die Vermittlung eines modernen Weltbildes durch Unterricht ist ein h{\"a}ufiger Wunsch in der naturwissenschaftlichen Bildungsdiskussion. Dennoch exis­tieren weiterhin Forschungs- und Entwicklungsbedarfe. Kosmologische Themen finden sich h{\"a}ufig in den Medien und sind gleichzeitig weiter vom Alltag entfernt, so dass sich hier besonders leicht wissenschaftlich inkorrekte Vorstellungen entwickeln k{\"o}nnen, die zu Problemen im Unterricht f{\"u}hren k{\"o}nnen. Das Ziel dieser wissenschaftlichen Arbeit ist es, zu diesem Forschungsgebiet beizutragen und die Voraussetzungen hinsichtlich vorhandener Vorkenntnisse und Pr{\"a}konzepte in Kosmologie, mit denen Sch{\"u}lerinnen und Sch{\"u}ler in den Unterricht kommen, zu untersuchen und anschließend mit denen anderer L{\"a}nder zu vergleichen. Dies erfolgt anhand einer qualitativen Inhaltsanalyse eines offenen Fragebogens. Auf dieser Grundlage wird schließlich ein Multiple-Choice Frage­bogen entwickelt, angewendet und evaluiert. Die Ergebnisse zeigen große Wissensl{\"u}cken im Bereich der Kosmologie auf und geben erste Hin­weise auf vorhandene Unterschiede zwischen den L{\"a}ndern. Es existieren ebenfalls einige teils weit verbreitete wissenschaftlich inkorrekte Vorstellungen wie beispiels­weise die Assoziation des Urknalls mit einer Explosion, der Urknall verursacht durch eine Kollision von Teilchen oder gr{\"o}ßeren Objekten, oder die Vorstellung der Ausdehnung des Universums als neue Entdeckungen und/oder Wissen. Des Weiteren gab nur etwa jeder F{\"u}nfte das korrekte Alter des Universums oder die Ausdehnung des Universums als einen der drei Belege der Urknalltheorie an, w{\"a}hrend fast 40\% keinen einzigen Beleg nennen konn­ten. F{\"u}r den geschlossenen Fragebogen konnten gute Hinweise f{\"u}r verschiedene Validit{\"a}tsa­spekte herausgearbeitet werden und es existieren erste Hinweise darauf, dass der Fragebogen Wissenszu­wachs messen kann und damit wahrscheinlich zur Unter­suchung der Wirksamkeit von Lerneinhei­ten eingesetzt werden kann. Auch ein entsprechendes Modell zur Verst{\"a}ndnisentwicklung der Aus­dehnung des Universums zeigte sich vielversprechend. Diese Arbeit liefert insgesamt einen Forschungsbeitrag zum Sch{\"u}lervorwissen und Vorstellungen in der Kosmologie und deren Large Scale Assessment. Dies er{\"o}ffnet die M{\"o}glichkeit zuk{\"u}nftiger For­schungen im Bereich von Gruppenvergleichen insbesondere hinsichtlich objektiver L{\"a}nderverglei­che sowie der Untersuchungen der Wirksamkeit von einzelnen Ler­neinheiten als auch Vergleiche verschiedener Lerneinheiten untereinander.},
  language  = {de}
}
@phdthesis{Arf2019,
  author    = {Arf, Shelan Ali},
  title     = {Women's everyday reality of social insecurity},
  doi       = {10.25932/publishup-43433},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434333},
  school      = {Universit{\"a}t Potsdam},
  pages     = {334},
  year      = {2019},
  abstract  = {Since 1980 Iraq passed through various wars and conflicts including Iraq-Iran war, Saddam Hussein's the Anfals and Halabja campaigns against the Kurds and the killing campaigns against Shiite in 1986, Saddam Hussein's invasion of Kuwait in August 1990, the Gulf war in 1990, Iraq war in 2003 and the fall of Saddam, the conflicts and chaos in the transmission of power after the death of Saddam, and the war against ISIS . All these wars left severe impacts in most households in Iraq; on women and children in particular. The consequences of such long wars could be observed in all sectors including economic, social, cultural and religious sectors. The social structure, norms and attitudes are intensely affected. Many women specifically divorced women found them-selves in challenging different difficulties such as social as well as economic situations. Thus the divorced women in Iraqi Kurdistan are the focus of this research. Considering the fact that there is very few empirical researches on this topic, a constructivist grounded theory methodology (CGT) is viewed as reliable in order to come up with a comprehensive picture about the everyday life of divorced women in Iraqi Kurdistan. Data collected in Sulaimani city in Iraqi Kurdistan. The work of Kathy Charmaz was chosen to be the main methodological context of the research and the main data collection method was individual intensive narrative interviews with divorced women. Women generally and divorced women specifically in Iraqi Kurdistan are living in a patriarchal society that passing through many changes due to the above mentioned wars among many other factors. This research is trying to study the everyday life of divorced women in such situations and the forms of social insecurity they are experiencing. The social institutions starting from the family as a very significant institution for women to the governmental and non-governmental institutions that are working to support women, and the copying strategies, are in focus in this research. The main research argument is that the family is playing ambivalent roles in divorced women's life. For instance, on one side families are revealed to be an essential source of security to most respondents, on the other side families posed also many threats and restrictions on those women. This argument supported by what called by Suad joseph "the paradox of support and suppression" . Another important finding is that the stat institution(laws , constitutions ,Offices of combating violence against woman and family) are supporting women somehow and offering them protection from the insecurities but it is clear that the existence of the laws does not stop the violence against women in Iraqi Kurdistan, As explained by Pateman because the laws /the contract is a sexual-social contract that upholds the sex rights of males and grants them more privileges than females. The political instability, Tribal social norms also play a major role in influencing the rule of law. It is noteworthy to refer that analyzing the interviews in this research showed that in spite that divorced women living in insecurities and facing difficulties but most of the respondents try to find a coping strategies to tackle difficult situations and to deal with the violence they face; these strategies are bargaining, sometimes compromising or resisting …etc. Different theories used to explain these coping strategies such as bargaining with patriarchy. Kandiyoti who stated that women living under certain restraints struggle to find way and strategies to enhance their situations. The research finding also revealed that the western liberal feminist view of agency is limited this is agree with Saba Mahmood and what she explained about Muslim women agency. For my respondents, who are divorced women, their agency reveals itself in different ways, in resisting or compromising with or even obeying the power of male relatives, and the normative system in the society. Agency is also explained the behavior of women contacting formal state institutions in cases of violence like the police or Offices of combating violence against woman and family.},
  language  = {en}
}
@phdthesis{BarqueroPipin2019,
  author    = {Barquero Pip{\´i}n, Antonio Carlos},
  title     = {Lengua, cultura, interculturalidad},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-480-7},
  doi       = {10.25932/publishup-43902},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-439023},
  school      = {Universit{\"a}t Potsdam},
  pages     = {429},
  year      = {2019},
  abstract  = {Ohne Pragmatik w{\"a}re Kommunikation nicht m{\"o}glich, da wir sprachliche Aussagen nicht interpretieren k{\"o}nnten. F{\"u}r jeden Lernenden einer Sprache, die er nicht beherrscht, reicht es nicht aus, sprachlich kompetent zu sein, da der Zweck der Kommunikation darin besteht, mit anderen Menschen und in bestimmten Kontexten zu kommunizieren. Nur eine Lehre, die es erm{\"o}glicht, Aussagen zur Durchf{\"u}hrung von Sprachhandlungen zu erstellen und zu verstehen und die f{\"u}r einen bestimmten Kontext am besten geeigneten auszuw{\"a}hlen, kann sich als effizient erweisen. Die hier vorgestellte Arbeit zielt darauf ab, der wissenschaftlichen Gemeinschaft und insbesondere denjenigen, die direkt und indirekt am Unterrichtsprozess beteiligt sind, das Konzept der verbalen Pragmatik bekannt zu machen und es anderen wie Grammatik, Kultur oder Interkulturalit{\"a}t gegen{\"u}ber zu stellen. Ferner wendet sie sich der Frage zu, wie man auf die Bedeutung und die dringende Notwendigkeit aufmerksam macht, Pragmatik als relevante Disziplin im Kommunikationsprozess zu etablieren; dabei wird insbesondere auf ihre systematische Einbeziehung in Lehrb{\"u}chern f{\"u}r Spanisch als Fremdsprache, die f{\"u}r den schulischen Kontext konzipiert wurden, abgestellt. Dazu werden das Vorhandensein pragmatischer Elemente und die F{\"o}rderung pragmatischer Kompetenz in Lehrb{\"u}chern f{\"u}r Anf{\"a}nger sowie ihre Relevanz bei der Festlegung von Inhalten, Fortschrittsart und Methodik untersucht.},
  language  = {es}
}
@phdthesis{Bartel2019,
  author    = {Bartel, Melanie},
  title     = {Kernresonanz-Strukturuntersuchungen an alternativen Precursoren und deren Zwischenprodukten f{\"u}r die Herstellung von Carbonfasern f{\"u}r den Massenmarkt},
  doi       = {10.25932/publishup-46930},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-469301},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XII, 101, XXV},
  year      = {2019},
  abstract  = {Carbonfasern haben sich in der Luft- und Raumfahrt etabliert und gewinnen in Alltagsanwendungen wie dem Automobilbereich, Windkraft- und Sportbereich durch ihre hohen Zugfestigkeiten, insbesondere ihrer hohen E-Moduli, und ihrer geringen Dichte immer mehr an Bedeutung. Auf Grund ihrer hohen Kosten, welche sich zur H{\"a}lfte aus der Precursorherstellung, inklusive seiner Synthese und seinem Verspinnprozess, dem L{\"o}sungsspinnverfahren, ergeben, erhalten zunehmend alternative und schmelzspinnbare Precursoren Interesse. F{\"u}r die Carbonfaserherstellung wird fast ausschließlich Polyacrylnitril (PAN) verwendet, das vor dem Schmelzen irreversible exotherme Zyklisierungsreaktionen aufweist, welchen sich seine Zersetzung anschließt. Eine M{\"o}glichkeit der Reduzierung der Schmelztemperatur von Polymeren ist die Einbringung von Comonomeren zur Erh{\"o}hung des freien Volumens und die Reduzierung der intermolekularen Wechselwirkungen als interne Weichmacher. Wie am Fraunhofer IAP gezeigt wurde, kann mittels 2-Methoxyethylacrylat (MEA) die Schmelztemperatur zu neuartigen PAN-basierten Precursoren verringert werden. Um den PAN-co-MEA-Precursor f{\"u}r die nachfolgenden Prozessschritte der Carbonfaserherstellung zu verwenden, m{\"u}ssen die thermoplastischen Fasern in thermisch stabile Fasern ohne thermoplastisches Verhalten {\"u}berf{\"u}hrt werden. Es wurde ein neuer Prozessschritt (Pr{\"a}stabilisierung) eingef{\"u}hrt, welcher unter alkalischen Bedingungen zur Abspaltung der Comonomerseitenkette f{\"u}hrt. Neben der Esterhydrolyse finden Reaktionen statt, welche an diesem Material noch nicht hinreichend untersucht wurden. Weiterhin stellt sich die Frage nach der Kinetik der Pr{\"a}stabilisierung und der Ermittlung einer geeigneten Prozessf{\"u}hrung. Hierzu wurde die Pr{\"a}stabilisierung in den Labormaßstab {\"u}berf{\"u}hrt und die m{\"o}glichen Zusammensetzungen des aus DMSO und einer KOH-L{\"o}sung bestehenden Reaktionsmediums evaluiert. Weiterhin wurde die Behandlung bei verschiedenen Pr{\"a}stabilisierungszeiten von maximal 30 min und Temperaturen von 40, 50 und 60 °C durchgef{\"u}hrt, um prim{\"a}r mittels NMR-Spektroskopie die chemischen Struktur{\"a}nderungen aufzukl{\"a}ren. Die Esterhydrolyse des Comonomers, welche zur Abspaltung des 2-Methoxyethanols f{\"u}hrt, wurde mittels 1H-NMR-spektroskopischer Untersuchungen detektiert. Es wurde ein Modell aufgestellt, das die chemisch-physikalischen Struktur{\"a}nderungen w{\"a}hrend der Pr{\"a}stabilisierung aufzeigt. Die zuerst ablaufende Reaktion ist die Esterhydrolyse am Comonomer, welche vom Faserrand nach innen verl{\"a}uft und durch die Pr{\"a}senz des DMSO in Kombination mit der KOH-L{\"o}sung (Superbase) initiiert wird. Der zeitliche Reaktionsverlauf der Esterhydrolyse kann in drei Bereiche eingeteilt werden. Der erste Bereich ab dem Pr{\"a}stabilisierungsbeginn wird durch die Diffusion der basischen Anionen in die Faser, der zweite Bereich durch die Reaktion an der Estergruppe des Comonomers und der dritte Bereich durch letzte Reaktionen im Faserinneren und diffusiven Prozessen der Produkte und Edukte charakterisiert. Der zweite Bereich kann mit einer Reaktion pseudo 1. Ordnung abgebildet werden, da in diesem Bereich bereits eine ausreichende Diffusion der Edukte in die Faser stattgefunden hat. Bei 50 °C spielt die Diffusion im ersten Bereich im Vergleich zur Reaktion eine untergeordnete Rolle. Mit Erh{\"o}hung der Temperatur auf 60 °C kann eine im Verh{\"a}ltnis geringere Diffusions- als Reaktionsgeschwindigkeit beobachtet werden. Die Nebenreaktionen wurden mittels 13C-CP/MAS-NMR-spektroskopischen, elementaranlaytischen Untersuchungen sowie Doppelbrechungsmessungen charakterisiert. W{\"a}hrend der alkalischen Esterhydrolyse beginnt die Reduzierung der Nitrilgruppen unter der Bildung von prim{\"a}ren Carbons{\"a}ureamiden und Carbons{\"a}uren. Zur Beschreibung dieser Umsetzung wurde eine Methode entwickelt, welche die Addition von 13C-CP/MAS-NMR-Spektren der Modellsubstanzen PAN, PAM und PAA beinhaltet. Weitere stattfindende Reaktionen sind die Bildung von konjugierten Doppelbindungen, welche insbesondere auf eine Zyklisierung der Nitrile hinweisen. Die nasschemisch initiierte Zyklisierung der Nitrilgruppen kann zu k{\"u}rzeren Stabilisierungszeiten und einem besser kontrollierbaren Stabilisierungsprozess durch geringere W{\"a}rmefreisetzung und schlussendlich zu einer Kostenersparnis des gesamten Verfahrens f{\"u}hren. Die Umsetzung der Nitrilgruppen konnte mit einer Reaktion pseudo 1. Ordnung gut abgebildet werden. DMSO initiiert die Esterhydrolyse, wobei die KOH-Konzentration einen h{\"o}heren Einfluss auf die Reaktionsgeschwindigkeit der Ester- und Nitrilhydrolyse als die DMSO-Konzentration besitzt. Beide Reaktionen zeigen eine vergleichbare Abh{\"a}ngigkeit von der Temperatur. Die Erh{\"o}hung der Pr{\"a}stabilisierungszeit und der KOH- bzw. DMSO-Konzentration f{\"u}hrt zur Migration niedermolekularer Bestandteile des Fasermaterials an die Oberfl{\"a}che und der Bildung punktueller Ablagerungen bis hin zu miteinander verbundenen Einzelfasern. Eine weitere Erh{\"o}hung der Pr{\"a}stabilisierungszeit bzw. der Konzentration f{\"u}hrt zu einem steigenden Carbons{\"a}ureanteil und zur Quellung des Fasermaterials, wodurch die Ablagerungen in das Reaktionsmedium diffundieren. Die Ablagerungen enthalten Chlor, welches durch den Waschvorgang mit HCl in das Materialsystem gelangt ist und durch Parameteranpassungen reduziert wurde. Die schmelzbaren Fasern konnten durch die Pr{\"a}stabilisierung erfolgreich {\"u}ber eine Kern-Mantel-Struktur in nicht-thermoplastische Fasern {\"u}berf{\"u}hrt werden. Zur Ermittlung eines geeigneten Prozessfensters f{\"u}r nachfolgende thermische Beanspruchungen der pr{\"a}stabilisierten Fasern wurden drei Kriterien identifiziert, anhand welcher die Evaluation erfolgte. Das erste Kriterium beinhaltet die Notwendigkeit der vollst{\"a}ndigen Aufhebung der thermoplastischen Eigenschaft der Fasern. Als zweites Kriterium diente die Fasermorphologie. Anhand von REM-Aufnahmen wurden Faserb{\"u}ndel mit separierten Einzelfasern ohne Ablagerungen f{\"u}r die nachfolgende Stabilisierung ausgew{\"a}hlt. Das dritte Kriterium bezieht sich auf eine m{\"o}glichst geringe Umsetzung der Nitrilgruppen, um Pr{\"a}stabilisierungsbedingungen mit Nebenreaktionen zu vermeiden. Aus den Untersuchungen konnte eine Pr{\"a}stabilisierungstemperatur von 60 °C als geeignet identifiziert werden. Weiterhin f{\"u}hren hoch alkalische Zusammensetzungen des Reaktionsmediums mit KOH-Konzentrationen von 1, 1,5 und 2 M, vorzugsweise 1,5 M und 50 vol\% DMSO mit Reaktionszeiten von unter 10 min zu geeigneten Fasern. Ein MEA-Anteil unterhalb von 2 mol\% bewirkt eine {\"U}berf{\"u}hrung in die Unschmelzbarkeit. Thermisch stabile und f{\"u}r die nachfolgende Stabilisierung geeignete Fasern besitzen weiterhin 68 - 80 mol\% Nitrilgruppen, 20 - 25 mol\% Carbons{\"a}uren, bis zu 15 mol\% prim{\"a}re Carbons{\"a}ureamide und zyklisierte Strukturen.},
  language  = {de}
}
@phdthesis{Batoulis2019,
  author    = {Batoulis, Kimon},
  title     = {Sound integration of process and decision models},
  doi       = {10.25932/publishup-43738},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-437386},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xviii, 155},
  year      = {2019},
  abstract  = {Business process management is an established technique for business organizations to manage and support their processes. Those processes are typically represented by graphical models designed with modeling languages, such as the Business Process Model and Notation (BPMN). Since process models do not only serve the purpose of documentation but are also a basis for implementation and automation of the processes, they have to satisfy certain correctness requirements. In this regard, the notion of soundness of workflow nets was developed, that can be applied to BPMN process models in order to verify their correctness. Because the original soundness criteria are very restrictive regarding the behavior of the model, different variants of the soundness notion have been developed for situations in which certain violations are not even harmful. All of those notions do only consider the control-flow structure of a process model, however. This poses a problem, taking into account the fact that with the recent release and the ongoing development of the Decision Model and Notation (DMN) standard, an increasing number of process models are complemented by respective decision models. DMN is a dedicated modeling language for decision logic and separates the concerns of process and decision logic into two different models, process and decision models respectively. Hence, this thesis is concerned with the development of decisionaware soundness notions, i.e., notions of soundness that build upon the original soundness ideas for process models, but additionally take into account complementary decision models. Similar to the various notions of workflow net soundness, this thesis investigates different notions of decision soundness that can be applied depending on the desired degree of restrictiveness. Since decision tables are a standardized means of DMN to represent decision logic, this thesis also puts special focus on decision tables, discussing how they can be translated into an unambiguous format and how their possible output values can be efficiently determined. Moreover, a prototypical implementation is described that supports checking a basic version of decision soundness. The decision soundness notions were also empirically evaluated on models from participants of an online course on process and decision modeling as well as from a process management project of a large insurance company. The evaluation demonstrates that violations of decision soundness indeed occur and can be detected with our approach.},
  language  = {en}
}
@phdthesis{Bauch2019,
  author    = {Bauch, Marcel},
  title     = {Untersuchungen an neuartigen sauerstoffsubstituierten Donoren und Akzeptoren f{\"u}r Singulettsauerstoff},
  doi       = {10.25932/publishup-42514},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-425140},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VI, 196, xiv, A-27},
  year      = {2019},
  abstract  = {Im Verlauf dieser Arbeit wurden Aromaten wie Naphthaline und Anthracene mit Singulettsauerstoff, einer reaktiven Form des gew{\"o}hnlichen Sauerstoffs, zu sogenannten Endoperoxiden umgesetzt. Die hier eingesetzten Systeme wurden mit funktionellen Gruppen modifiziert, die {\"u}ber eine Sauerstoffbr{\"u}cke mit dem Aromaten verkn{\"u}pft sind. Die daraus entstandenen Endoperoxide sind meist besonders labil und konnten in dieser Arbeit isoliert und umfassend untersucht werden. Hierbei wurde zum einen das Reaktionsverhalten untersucht. Es konnte gezeigt werden, dass die Aromaten in Abh{\"a}ngigkeit ihrer funktionellen Gruppen unterschiedlich schnell mit Singulettsauerstoff reagieren. Die so ermittelten Reaktivit{\"a}ten wurden zus{\"a}tzlich durch theoretische Berechnungen gest{\"u}tzt. Die resultierenden Endoperoxide wurden unter verschiedenen Bedingungen wie erh{\"o}hter Temperatur oder einem sauren bzw. basischen Milieu auf ihre Stabilit{\"a}t hin untersucht. Dabei konnte gezeigt werden, dass die auf Naphthalinen basierenden Endoperoxiden den gebundenen Singulettsauerstoff in guten Ausbeuten oft schon bei sehr niedrigen Temperaturen (-40 bis 0 °C) freisetzen. Diese Verbindungen k{\"o}nnen daher als milde Quellen dieser reaktiven Sauerstoffspezies eingesetzt werden. Weiterhin konnten bei den Anthracenendoperoxiden Zerfallsmechanismen aufgekl{\"a}rt und andere reaktive Sauerstoffspezies wie Wasserstoffperoxid oder Pers{\"a}uren nachgewiesen werden. Zu den Modifikationen der Aromaten geh{\"o}ren auch Glucosereste. Dadurch k{\"o}nnten sich die hier hergestellten Endoperoxide als vielversprechende Verbindungen in der Krebstherapie herausstellen, da Krebszellen deutlich st{\"a}rker als gesunde Zellen kohlenhydratreiche Verbindungen f{\"u}r ihren Stoffwechsel ben{\"o}tigen. Bei der Spaltung von Endoperoxiden mit Glucosesubstituenten werden ebenfalls reaktive Sauerstoffspezies frei, die so zum Zelltod f{\"u}hren k{\"o}nnten.},
  language  = {de}
}
@phdthesis{Beamish2019,
  author    = {Beamish, Alison Leslie},
  title     = {Hyperspectral remote sensing of the spatial and temporal heterogeneity of low Arctic vegetation},
  doi       = {10.25932/publishup-42592},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-425922},
  school      = {Universit{\"a}t Potsdam},
  pages     = {v, 102},
  year      = {2019},
  abstract  = {Arctic tundra ecosystems are experiencing warming twice the global average and Arctic vegetation is responding in complex and heterogeneous ways. Shifting productivity, growth, species composition, and phenology at local and regional scales have implications for ecosystem functioning as well as the global carbon and energy balance. Optical remote sensing is an effective tool for monitoring ecosystem functioning in this remote biome. However, limited field-based spectral characterization of the spatial and temporal heterogeneity limits the accuracy of quantitative optical remote sensing at landscape scales. To address this research gap and support current and future satellite missions, three central research questions were posed: • Does canopy-level spectral variability differ between dominant low Arctic vegetation communities and does this variability change between major phenological phases? • How does canopy-level vegetation colour images recorded with high and low spectral resolution devices relate to phenological changes in leaf-level photosynthetic pigment concentrations? • How does spatial aggregation of high spectral resolution data from the ground to satellite scale influence low Arctic tundra vegetation signatures and thereby what is the potential of upcoming hyperspectral spaceborne systems for low Arctic vegetation characterization? To answer these questions a unique and detailed database was assembled. Field-based canopy-level spectral reflectance measurements, nadir digital photographs, and photosynthetic pigment concentrations of dominant low Arctic vegetation communities were acquired at three major phenological phases representing early, peak and late season. Data were collected in 2015 and 2016 in the Toolik Lake Research Natural Area located in north central Alaska on the North Slope of the Brooks Range. In addition to field data an aerial AISA hyperspectral image was acquired in the late season of 2016. Simulations of broadband Sentinel-2 and hyperspectral Environmental and Mapping Analysis Program (EnMAP) satellite reflectance spectra from ground-based reflectance spectra as well as simulations of EnMAP imagery from aerial hyperspectral imagery were also obtained. Results showed that canopy-level spectral variability within and between vegetation communities differed by phenological phase. The late season was identified as the most discriminative for identifying many dominant vegetation communities using both ground-based and simulated hyperspectral reflectance spectra. This was due to an overall reduction in spectral variability and comparable or greater differences in spectral reflectance between vegetation communities in the visible near infrared spectrum. Red, green, and blue (RGB) indices extracted from nadir digital photographs and pigment-driven vegetation indices extracted from ground-based spectral measurements showed strong significant relationships. RGB indices also showed moderate relationships with chlorophyll and carotenoid pigment concentrations. The observed relationships with the broadband RGB channels of the digital camera indicate that vegetation colour strongly influences the response of pigment-driven spectral indices and digital cameras can track the seasonal development and degradation of photosynthetic pigments. Spatial aggregation of hyperspectral data from the ground to airborne, to simulated satel-lite scale was influenced by non-photosynthetic components as demonstrated by the distinct shift of the red edge to shorter wavelengths. Correspondence between spectral reflectance at the three scales was highest in the red spectrum and lowest in the near infra-red. By artificially mixing litter spectra at different proportions to ground-based spectra, correspondence with aerial and satellite spectra increased. Greater proportions of litter were required to achieve correspondence at the satellite scale. Overall this thesis found that integrating multiple temporal, spectral, and spatial data is necessary to monitor the complexity and heterogeneity of Arctic tundra ecosystems. The identification of spectrally similar vegetation communities can be optimized using non-peak season hyperspectral data leading to more detailed identification of vegetation communities. The results also highlight the power of vegetation colour to link ground-based and satellite data. Finally, a detailed characterization non-photosynthetic ecosystem components is crucial for accurate interpretation of vegetation signals at landscape scales.},
  language  = {en}
}
@phdthesis{Behm2019,
  author    = {Behm, Laura Vera Johanna},
  title     = {Thermoresponsive Zellkultursubstrate f{\"u}r zeitlich-r{\"a}umlich gesteuertes Auswachsen neuronaler Zellen},
  doi       = {10.25932/publishup-43619},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-436196},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VII, 105},
  year      = {2019},
  abstract  = {Ein wichtiges Ziel der Neurowissenschaften ist das Verst{\"a}ndnis der komplexen und zugleich faszinierenden, hochgeordneten Vernetzung der Neurone im Gehirn, welche neuronalen Prozessen, wie zum Beispiel dem Wahrnehmen oder Lernen wie auch Neuropathologien zu Grunde liegt. F{\"u}r verbesserte neuronale Zellkulturmodelle zur detaillierten Untersuchung dieser Prozesse ist daher die Rekonstruktion von geordneten neuronalen Verbindungen dringend erforderlich. Mit Oberfl{\"a}chenstrukturen aus zellattraktiven und zellabweisenden Beschichtungen k{\"o}nnen neuronale Zellen und ihre Neuriten in vitro strukturiert werden. Zur Kontrolle der neuronalen Verbindungsrichtung muss das Auswachsen der Axone zu benachbarten Zellen dynamisch gesteuert werden, zum Beispiel {\"u}ber eine ver{\"a}nderliche Zug{\"a}nglichkeit der Oberfl{\"a}che. In dieser Arbeit wurde untersucht, ob mit thermoresponsiven Polymeren (TRP) beschichtete Zellkultursubstrate f{\"u}r eine dynamische Kontrolle des Auswachsens neuronaler Zellen geeignet sind. TRP k{\"o}nnen {\"u}ber die Temperatur von einem zellabweisenden in einen zellattraktiven Zustand geschaltet werden, womit die Zug{\"a}nglichkeit der Oberfl{\"a}che f{\"u}r Zellen dynamisch gesteuert werden kann. Die TRP-Beschichtung wurde mikrostrukturiert, um einzelne oder wenige neuronale Zellen zun{\"a}chst auf der Oberfl{\"a}che anzuordnen und das Auswachsen der Zellen und Neuriten {\"u}ber definierte TRP-Bereiche in Abh{\"a}ngigkeit der Temperatur zeitlich und r{\"a}umlich zu kontrollieren. Das Protokoll wurde mit der neuronalen Zelllinie SH-SY5Y etabliert und auf humane induzierte Neurone {\"u}bertragen. Die Anordnung der Zellen konnte bei Kultivierung im zellabweisenden Zustand des TRPs f{\"u}r bis zu 7 Tage aufrecht erhalten werden. Durch Schalten des TRPs in den zellattraktiven Zustand konnte das Auswachsen der Neuriten und Zellen zeitlich und r{\"a}umlich induziert werden. Immunozytochemische F{\"a}rbungen und Patch-Clamp-Ableitungen der Neurone demonstrierten die einfache Anwendbarkeit und Zellkompatibilit{\"a}t der TRP-Substrate. Eine pr{\"a}zisere r{\"a}umliche Kontrolle des Auswachsens der Zellen sollte durch lokales Schalten der TRP-Beschichtung erreicht werden. Daf{\"u}r wurden Mikroheizchips mit Mikroelektroden zur lokalen Jouleschen Erw{\"a}rmung der Substratoberfl{\"a}che entwickelt. Zur Evaluierung der generierten Temperaturprofile wurde eine Temperaturmessmethode entwickelt und die erhobenen Messwerte mit numerisch simulierten Werten abgeglichen. Die Temperaturmessmethode basiert auf einfach zu applizierenden Sol-Gel-Schichten, die den temperatursensitiven Fluoreszenzfarbstoff Rhodamin B enthalten. Sie erm{\"o}glicht oberfl{\"a}chennahe Temperaturmessungen in trockener und w{\"a}ssriger Umgebung mit hoher Orts- und Temperaturaufl{\"o}sung. Numerische Simulationen der Temperaturprofile korrelierten gut mit den experimentellen Daten. Auf dieser Basis konnten Geometrie und Material der Mikroelektroden hinsichtlich einer lokal stark begrenzten Temperierung optimiert werden. Ferner wurden f{\"u}r die Kultvierung der Zellen auf den Mikroheizchips eine Zellkulturkammer und Kontaktboard f{\"u}r die elektrische Kontaktierung der Mikroelektroden geschaffen. Die vorgestellten Ergebnisse demonstrieren erstmalig das enorme Potential thermoresponsiver Zellkultursubstrate f{\"u}r die zeitlich und r{\"a}umlich gesteuerte Formation geordneter neuronaler Verbindungen in vitro. Zuk{\"u}nftig k{\"o}nnte dies detaillierte Studien zur neuronalen Informationsverarbeitung oder zu Neuropathologien an relevanten, humanen Zellmodellen erm{\"o}glichen.},
  language  = {de}
}
@phdthesis{BernaschinaSchuermann2019,
  author    = {Bernaschina Sch{\"u}rmann, Vicente},
  title     = {{\´A}ngeles que cantan de continuo},
  isbn      = {978-3-86956-459-3},
  issn      = {2629-2548},
  doi       = {10.25932/publishup-42645},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426450},
  school      = {Universit{\"a}t Potsdam},
  pages     = {387},
  year      = {2019},
  abstract  = {Objeto de esta investigaci{\´o}n es el auge y ca{\´i}da de una legitimaci{\´o}n teol{\´o}gica de la poes{\´i}a que tuvo lugar en el virreinato del Per{\´u} entre fines del siglo XVI y la segunda mitad del siglo XVII. Su punto c{\´u}lmine est{\´a} marcado por el surgimiento de una "Academia Ant{\´a}rtica" en las primeras d{\´e}cadas del siglo XVII, mientras que su fin, se aprecia a fines del mismo siglo, cuando eruditos de las {\´o}rdenes religiosas, especialmente Juan de Espinosa y Medrano en sus textos en defensa de la poes{\´i}a y las ciencias, negaron a la poes{\´i}a cualquier estatuto teol{\´o}gico, sirvi{\´e}ndose sin embargo de ella para escribir sus sermones y textos. A partir del auge y ca{\´i}da de esta legitimaci{\´o}n teol{\´o}gica en el virreinato del Per{\´u}, este estudio muestra la existencia de dos movimientos que forman un quiasmo entre una teologizaci{\´o}n de la poes{\´i}a y una poetizaci{\´o}n de la teolog{\´i}a, en cuyo centro velado se encuentra en disputa el saber te{\´o}rico y pr{\´a}ctico de la poes{\´i}a. Lo que est{\´a} en disputa en este sentido no es la poes{\´i}a, entendida como una cumbre de las bellas letras, sino la posesi{\´o}n leg{\´i}tima de un modo de lectura anal{\´o}gico y tipol{\´o}gico del orden del universo, fundado en las Sagradas Escrituras y en la historia de la salvaci{\´o}n, y un modo po{\´e}tico para doctrinar a todos los miembros de la sociedad virreinal en concordancia con aquel modo de lectura.},
  language  = {es}
}
@phdthesis{Bieri2019,
  author    = {Bieri, Pascal},
  title     = {Topmanager im Kreuzfeuer ihrer Dilemmata},
  doi       = {10.25932/publishup-44106},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441062},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIII, 301},
  year      = {2019},
  abstract  = {Die vorliegende Forschungsarbeit untersucht den Umgang mit Dilemmata von Topmanagern. Dilemmata sind ein allt{\"a}gliches Gesch{\"a}ft im Topmanagement. Die entsprechenden Akteure sind daher immer wieder mit diesen konfrontiert und mit ihnen umzugehen, geh{\"o}rt gewissermaßen zu ihrer Berufsbeschreibung. Hinzu kommen Dilemmata im nicht direkt gesch{\"a}ftlichen Bereich, wie zum Beispiel jene zwischen Familien- und Arbeitszeit. Doch stellt dieses Feld ein kaum untersuchtes Forschungsgebiet dar. W{\"a}hrend Dilemmata in anderen Bereichen eine zunehmende Aufmerksamkeit erfuhren, wurden deren Besonderheiten im Topmanagement genauso wenig differenziert betrachtet wie zugeh{\"o}rige Umgangsweisen. Theorie und Praxis stellen bez{\"u}glich Dilemmata von Topmanagern vor allem einen Gegensatz dar, beziehungsweise fehlt es an einer theoretischen Fundierung der Empirie. Diesem Umstand wird mittels dieser Studie begegnet. Auf der Grundlage einer differenzierten und breiten Erfassung von Theorien zu Dilemmata, so diese auch noch nicht auf Topmanager bezogen wurden, und einer empirischen Erhebung, die im Mittelpunkt dieser Arbeit stehen, soll das Feld Dilemmata von Topmanagern der Forschung ge{\"o}ffnet werden. Empirische Grundlage sind vor allem narrative Interviews mit Topmanagern {\"u}ber ihre Dilemmata-Wahrnehmung, ausgemachte Ursachen, Umgangsweisen und Resultate. Dies erlaubt es, Topmanagertypen sowie Dilemmata-Arten, mit denen sie konfrontiert sind oder waren, analytisch herauszuarbeiten. Angesichts der Praxisrelevanz von Dilemmata von Topmanagern wird jedoch nicht nur ein theoretisches Modell zu dieser Thematik erarbeitet, es werden auch Reflexionen auf die Praxis in Form von Handlungsempfehlungen vorgenommen. Schließlich gilt es, die allgemeine Theorie zu Dilemmata, ohne konkreten Bezug zu Topmanagern, mit den theoretischen Erkenntnissen dieser Studie auf empirischer Basis zu kontrastieren. Dabei wird im Rahmen der empirischen Erfassung und Auswertung dem Ansatz der Grounded-Theory-Methodologie gefolgt.},
  language  = {de}
}
@phdthesis{Brandt2019,
  author    = {Brandt, Christopher Georg},
  title     = {"… when the legend becomes fact …"},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-429-6},
  doi       = {10.25932/publishup-41044},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-410441},
  school      = {Universit{\"a}t Potsdam},
  pages     = {377},
  year      = {2019},
  abstract  = {Der historische Spielfilm z{\"a}hlt zu den popul{\"a}rsten Formen geschichtskultureller Artikulation. Als solche ist er Gegenstand kontroverser Diskussionen {\"u}ber einen angemessenen didaktischen Umgang. Vor diesem Hintergrund ist es das Ziel der vorliegenden Arbeit, ein integratives, theoretisch und empirisch abgesichertes Analysemodell zu entwickeln, das nach den Tiefenstrukturen historischen Erz{\"a}hlens im Medium des Spielfilms fragt und dabei unterschiedliche Erscheinungsformen historischer Spielfilme ber{\"u}cksichtigt. Die {\"U}berlegungen bewegen sich deshalb in einem interdisziplin{\"a}ren Spannungsfeld von Theorien zum historischen Erz{\"a}hlen und Konzepten der Literatur- und Filmwissenschaft. Die Diskussion und Synthese dieser unterschiedlichen Konzepte geht dabei - auf der Grundlage einer großen Materialbasis - vom Gegenstand aus und ist induktiv angelegt. Als Orientierung f{\"u}r die praktische Arbeit werden am Ende der einzelnen Kapitel Toolkits entwickelt, die zu einer vertieften Auseinandersetzung mit historischen Spielfilmen anregen sollen.},
  language  = {de}
}
@phdthesis{Brase2019,
  author    = {Brase, Alexa Kristin},
  title     = {Spiele um Studium und Lehre? Zur mikropolitischen Nutzung von Qualit{\"a}tsmanagementsystemen an Hochschulen in Deutschland},
  doi       = {10.25932/publishup-43737},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-437377},
  school      = {Universit{\"a}t Potsdam},
  pages     = {IX, 228},
  year      = {2019},
  abstract  = {Die Wissenschaftsfreiheit ist ein Grundrecht, dessen Sinn und Auslegung im Rahmen von Reformen des Hochschulsystems nicht nur der Justiz, sondern auch der Wissenschaft selbst immer wieder Anlass zur Diskussion geben, so auch im Zuge der Einf{\"u}hrung des so genannten Qualit{\"a}tsmanagements von Studium und Lehre an deutschen Hochschulen. Die vorliegende Dissertationsschrift stellt die Ergebnisse einer empirischen Studie vor, die mit einer soziologischen Betrachtung des Qualit{\"a}tsmanagements unterschiedlicher Hochschulen zu dieser Diskussion beitr{\"a}gt. Auf Grundlage der Pr{\"a}misse, dass Verlauf und Folgen einer organisationalen Innovation nur verstanden werden k{\"o}nnen, wenn der allt{\"a}gliche Umgang der Organisationsmitglieder mit den neuen Strukturen und Prozessen in die Analyse einbezogen wird, geht die Studie von der Frage aus, wie Akteurinnen und Akteure an deutschen Hochschulen die Qualit{\"a}tsmanagementsysteme ihrer Organisationen nutzen. Die qualitative inhaltsanalytische Auswertung von 26 Leitfaden-Interviews mit Prorektorinnen und -rektoren, Qualit{\"a}tsmanagement-Personal und Studiendekaninnen und -dekanen an neun Hochschulen ergibt, dass die Strategien der Akteursgruppen an den Hochschulen im Zusammenspiel mit strukturellen Aspekten unterschiedliche Dynamiken entstehen lassen, mit denen Implikationen f{\"u}r die Lehrfreiheit verbunden sind: W{\"a}hrend die Autonomie der Lehrenden durch das Qualit{\"a}tsmanagement an einigen Hochschulen unterst{\"u}tzt wird, sind sowohl Autonomie als auch Verantwortung f{\"u}r Studium und Lehre an anderen Hochschulen Gegenstand andauernder Konflikte, die auch das Qualit{\"a}tsmanagement einschließen.},
  language  = {de}
}
@phdthesis{Brechun2019,
  author    = {Brechun, Katherine E.},
  title     = {Development and application of genetic networks for engineering photo-controlled proteins},
  doi       = {10.25932/publishup-43092},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430924},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxiv, 195},
  year      = {2019},
  abstract  = {Light-switchable proteins are being used increasingly to understand and manipulate complex molecular systems. The success of this approach has fueled the development of tailored photo-switchable proteins, to enable targeted molecular events to be studied using light. The development of novel photo-switchable tools has to date largely relied on rational design. Complementing this approach with directed evolution would be expected to facilitate these efforts. Directed evolution, however, has been relatively infrequently used to develop photo-switchable proteins due to the challenge presented by high-throughput evaluation of switchable protein activity. This thesis describes the development of two genetic circuits that can be used to evaluate libraries of switchable proteins, enabling optimization of both the on- and off-states. A screening system is described, which permits detection of DNA-binding activity based on conditional expression of a fluorescent protein. In addition, a tunable selection system is presented, which allows for the targeted selection of protein-protein interactions of a desired affinity range. This thesis additionally describes the development and characterization of a synthetic protein that was designed to investigate chromophore reconstitution in photoactive yellow protein (PYP), a promising scaffold for engineering photo-controlled protein tools.},
  language  = {en}
}
@phdthesis{Burmester2019,
  author    = {Burmester, Juliane},
  title     = {Linguistic and visual salience in sentence comprehension},
  doi       = {10.25932/publishup-44315},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-443155},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XI, 165},
  year      = {2019},
  abstract  = {Interlocutors typically link their utterances to the discourse environment and enrich communication by linguistic (e.g., information packaging) and extra-linguistic (e.g., eye gaze, gestures) means to optimize information transfer. Psycholinguistic studies underline that ‒for meaning computation‒ listeners profit from linguistic and visual cues that draw their focus of attention to salient information. This dissertation is the first work that examines how linguistic compared to visual salience cues influence sentence comprehension using the very same experimental paradigms and materials, that is, German subject-before-object (SO) and object-before-subject (OS) sentences, across the two cue modalities. Linguistic salience was induced by indicating a referent as the aboutness topic. Visual salience was induced by implicit (i.e., unconscious) or explicit (i.e., shared) manipulations of listeners' attention to a depicted referent. In Study 1, a selective, facilitative impact of linguistic salience on the context-sensitive OS word order was found using offline comprehensibility judgments. More precisely, during online sentence processing, this impact was characterized by a reduced sentence-initial Late positivity which reflects reduced processing costs for updating the current mental representation of discourse. This facilitative impact of linguistic salience was not replicated by means of an implicit visual cue (Study 2) shown to modulate word order preferences during sentence production. However, a gaze shift to a depicted referent as an indicator of shared attention eased sentence-initial processing similar to linguistic salience as revealed by reduced reading times (Study 3). Yet, this cue did not modulate the strong subject-antecedent preference during later pronoun resolution like linguistic salience. Taken together, these findings suggest a significant impact of linguistic and visual salience cues on sentence comprehension, which substantiates that both the information delivered via language and via the visual environment is integrated into the mental representation of the discourse; but, the way how salience is induced is crucial to its impact.},
  language  = {en}
}
@phdthesis{Boehne2019,
  author    = {B{\"o}hne, Sebastian},
  title     = {Different degrees of formality},
  doi       = {10.25932/publishup-42379},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-423795},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VI, 167},
  year      = {2019},
  abstract  = {In this thesis we introduce the concept of the degree of formality. It is directed against a dualistic point of view, which only distinguishes between formal and informal proofs. This dualistic attitude does not respect the differences between the argumentations classified as informal and it is unproductive because the individual potential of the respective argumentation styles cannot be appreciated and remains untapped. This thesis has two parts. In the first of them we analyse the concept of the degree of formality (including a discussion about the respective benefits for each degree) while in the second we demonstrate its usefulness in three case studies. In the first case study we will repair Haskell B. Curry's view of mathematics, which incidentally is of great importance in the first part of this thesis, in light of the different degrees of formality. In the second case study we delineate how awareness of the different degrees of formality can be used to help students to learn how to prove. Third, we will show how the advantages of proofs of different degrees of formality can be combined by the development of so called tactics having a medium degree of formality. Together the three case studies show that the degrees of formality provide a convincing solution to the problem of untapped potential.},
  language  = {en}
}
@phdthesis{Cecchini2019,
  author    = {Cecchini, Gloria},
  title     = {Improving network inference by overcoming statistical limitations},
  doi       = {10.25932/publishup-42670},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426705},
  school      = {Universit{\"a}t Potsdam},
  pages     = {124},
  year      = {2019},
  abstract  = {A reliable inference of networks from data is of key interest in many scientific fields. Several methods have been suggested in the literature to reliably determine links in a network. These techniques rely on statistical methods, typically controlling the number of false positive links, but not considering false negative links. In this thesis new methodologies to improve network inference are suggested. Initial analyses demonstrate the impact of falsepositive and false negative conclusions about the presence or absence of links on the resulting inferred network. Consequently, revealing the importance of making well-considered choices leads to suggest new approaches to enhance existing network reconstruction methods. A simulation study, presented in Chapter 3, shows that different values to balance false positive and false negative conclusions about links should be used in order to reliably estimate network characteristics. The existence of type I and type II errors in the reconstructed network, also called biased network, is accepted. Consequently, an analytic method that describes the influence of these two errors on the network structure is explored. As a result of this analysis, an analytic formula of the density of the biased vertex degree distribution is found (Chapter 4). In the inverse problem, the vertex degree distribution of the true underlying network is analytically reconstructed, assuming the probabilities of type I and type II errors. Chapters 4-5 show that the method is robust to incorrect estimates of α and β within reasonable limits. In Chapter 6, an iterative procedure to enhance this method is presented in the case of large errors on the estimates of α and β. The investigations presented so far focus on the influence of false positive and false negative links on the network characteristics. In Chapter 7, the analysis is reversed - the study focuses on the influence of network characteristics on the probability of type I and type II errors, in the case of networks of coupled oscillators. The probabilities of α and β are influenced by the shortest path length and the detour degree, respectively. These results have been used to improve the network reconstruction, when the true underlying network is not known a priori, introducing a novel and advanced concept of threshold.},
  language  = {en}
}
@phdthesis{Civitillo2019,
  author    = {Civitillo, Sauro},
  title     = {Teachers' cultural diversity beliefs and culturally responsive practices},
  doi       = {10.25932/publishup-42776},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427763},
  school      = {Universit{\"a}t Potsdam},
  pages     = {161},
  year      = {2019},
  abstract  = {The present dissertation about teachers' cultural diversity beliefs and culturally responsive practices includes a general introduction (Chapter 1), a systematic literature review (Chapter 2), three empirical studies (Chapter 3, 4, and 5) and it ends with a general discussion and conclusion (Chapter 6). The major focus of investigation laid in creating a deeper understanding of teachers' beliefs about cultural diversity and how those beliefs are related to teaching practices, which could or could not be considered to be culturally responsive. In this dissertation, I relied on insights from theoretical perspectives that derived from the field of psychology such as social cognitive theory and intergroup ideologies, as well as from the field of multicultural education such as culturally responsive teaching. In Chapter 1, I provide the background of this dissertation, with contextual information regarding the German educational system, the theoretical framework used and the main research objectives of each study. In Chapter 2, I conducted a systematic review of the existing international studies on trainings addressing cultural diversity beliefs with pre-service teachers. More specifically, the aims of the systematic literature review were (1) to provide a description of main components and contextual characteristics of teacher trainings targeting cultural diversity beliefs, (2) report the training effects, and (3) detail the methodological strengths and weaknesses of these studies. By examining the main components and contextual characteristics of teacher trainings, the effects on beliefs about cultural diversity as well as the methodological strengths and weaknesses of these studies in a single review, I took an integrated approach to these three processes. To review the final pool of studies (N = 36) I used a descriptive and narrative approach, relying primarily on the use of words and text to summarise and explain findings of the synthesis. The three empirical studies that follow, all highlight aspects of how far and how teacher beliefs about cultural diversity translate into real-world practices in schools. In Chapter 3, to expand the validity of culturally responsive teaching to the German context, I aimed at verifying the dimensional structure of German version of the Culturally Responsive Classroom Management Self-Efficacy Scale (CRCMSES; Siwatu, Putman, Starker-Glass, \& Lewis, 2015). I conducted Exploratory and Confirmatory Factor Analysis, and run correlations between the subscales of the CRCMSES and a measure of cultural diversity- related stress. Data (n = 504) used for the first empirical study (Chapter 3) were collected in the InTePP-project (Inclusive Teaching Professionalization Panel) in which pre-service teachers' competencies and beliefs were assessed longitudinally at two universities: the University of Potsdam and the University of Cologne. In the second empirical study, which forms Chapter 4, the focus is on teachers' practices resembling school approaches to cultural diversity. In this study, I investigated two research questions: (1a) What types of descriptive norms regarding cultural diversity are perceived by teachers and students with and without an immigrant background and (1b) what is their degree of congruence? Additionally, I was also interested in how are teachers' and students' perceptions of descriptive norms about cultural diversity related to practices and artefacts in the physical and virtual school environment? Data for the second empirical study (Chapter 4) were previously collected in a dissertation project of doctor Maja Schachner funded by the federal program "ProExzellenz" of the Free State of Thuringia. Adopting a mixed-methods research design I conducted a secondary analysis of data from teachers' (n = 207) and students' (n = 1,644) gathered in 22 secondary schools in south-west Germany. Additional sources of data in this study were based on pictures of school interiors (hall and corridors) and sixth-grade classrooms' walls (n = 2,995), and screenshots from each school website (n = 6,499). Chapter 5 addresses the question of how culturally responsive teaching, teacher cultural diversity beliefs, and self-reflection on own teaching are related. More specifically, in this study I addressed two research questions: (1) How does CRT relate to teachers' beliefs about incorporating cultural diversity content into daily teaching and learning activities? And (2) how does the level of teachers' self-reflection on their own teaching relate to CRT? For this last empirical chapter, I conducted a multiple case study with four ethnic German teachers who work in one culturally and ethnically diverse high school in Berlin, using classroom video observations and post-observation interviews. In the final chapter (Chapter 6), I summarised the main findings of the systematic literature review and three empirical studies, and discuss their scientific and practical implications. This dissertation makes a significant contribution to the field of educational science to understanding culturally responsive teaching in terms of its measurement, focus on both beliefs and practices and the link between the two, and theoretical, practical, and future study implications.},
  language  = {en}
}
@phdthesis{Codeco2019,
  author    = {Codeco, Marta Sofia Ferreira},
  title     = {Constraining the hydrology at Minas da Panasqueira W-Sn-Cu deposit, Portugal},
  doi       = {10.25932/publishup-42975},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429752},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxviii, 232},
  year      = {2019},
  abstract  = {This dissertation combines field and geochemical observations and analyses with numerical modeling to understand the formation of vein-hosted Sn-W ore in the Panasqueira deposit of Portugal, which is among the ten largest worldwide. The deposit is located above a granite body that is altered by magmatic-hydrothermal fluids in its upper part (greisen). These fluids are thought to be the source of metals, but that was still under debate. The goal of this study is to determine the composition and temperature of hydrothermal fluids at Panasqueira, and with that information to construct a numerical model of the hydrothermal system. The focus is on analysis of the minerals tourmaline and white mica, which formed during mineralization and are widespread throughout the deposit. Tourmaline occurs mainly in alteration zones around mineralized veins and is less abundant in the vein margins. White mica is more widespread. It is abundant in vein margins as well as alteration zones, and also occurs in the granite greisen. The laboratory work involved in-situ microanalysis of major- and trace elements in tourmaline and white mica, and boron-isotope analysis in both minerals by secondary ion mass spectrometry (SIMS). The boron-isotope composition of tourmaline and white mica suggests a magmatic source. Comparison of hydrothermally-altered and unaltered rocks from drill cores shows that the ore metals (W, Sn, Cu, and Zn) and As, F, Li, Rb, and Cs were introduced during the alteration. Most of these elements are also enriched in tourmaline and mica, which confirms their potential value as exploration guides to Sn-W ores elsewhere. The thermal evolution of the hydrothermal system was estimated by B-isotope exchange thermometry and the Ti-in-quartz method. Both methods yielded similar temperatures for the early hydrothermal phase: 430° to 460°C for B-isotopes and 503° ± 24°C for Ti-in-quartz. Mineral pairs from a late fault zone yield significantly lower median temperatures of 250°C. The combined results of thermometry with variations in chemical and B-isotope composition of tourmaline and mica suggest that a similar magmatic-hydrothermal fluid was active at all stages of mineralization. Mineralization in the late stage shows the same B-isotope composition as in the main stage despite a ca. 250°C cooling, which supports a multiple injection model of magmatic-hydrothermal fluids. Two-dimensional numerical simulations of convection in a multiphase NaCl hydrothermal system were conducted: (a) in order to test a new approach (lower dimensional elements) for flow through fractures and faults and (b) in order to identify conditions for horizontal fluid flow as observed in the flat-lying veins at Panasqueira. The results show that fluid flow over an intrusion (heat and fluid source) develops a horizontal component if there is sufficient fracture connectivity. Late, steep fault zones have been identified in the deposit area, which locally contain low-temperature Zn-Pb mineralization. The model results confirm that the presence of subvertical faults with enhanced permeability play a crucial role in the ascent of magmatic fluids to the surface and the recharge of meteoric waters. Finally, our model results suggest that recharge of meteoric fluids and mixing processes may be important at later stages, while flow of magmatic fluids dominate the early stages of the hydrothermal fluid circulation.},
  language  = {en}
}
@phdthesis{Crisologo2019,
  author    = {Crisologo, Irene},
  title     = {Using spaceborne radar platforms to enhance the homogeneity of weather radar calibration},
  doi       = {10.25932/publishup-44570},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-445704},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvii, 61},
  year      = {2019},
  abstract  = {Accurate weather observations are the keystone to many quantitative applications, such as precipitation monitoring and nowcasting, hydrological modelling and forecasting, climate studies, as well as understanding precipitation-driven natural hazards (i.e. floods, landslides, debris flow). Weather radars have been an increasingly popular tool since the 1940s to provide high spatial and temporal resolution precipitation data at the mesoscale, bridging the gap between synoptic and point scale observations. Yet, many institutions still struggle to tap the potential of the large archives of reflectivity, as there is still much to understand about factors that contribute to measurement errors, one of which is calibration. Calibration represents a substantial source of uncertainty in quantitative precipitation estimation (QPE). A miscalibration of a few dBZ can easily deteriorate the accuracy of precipitation estimates by an order of magnitude. Instances where rain cells carrying torrential rains are misidentified by the radar as moderate rain could mean the difference between a timely warning and a devastating flood. Since 2012, the Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) has been expanding the country's ground radar network. We had a first look into the dataset from one of the longest running radars (the Subic radar) after devastating week-long torrential rains and thunderstorms in August 2012 caused by the annual southwestmonsoon and enhanced by the north-passing Typhoon Haikui. The analysis of the rainfall spatial distribution revealed the added value of radar-based QPE in comparison to interpolated rain gauge observations. However, when compared with local gauge measurements, severe miscalibration of the Subic radar was found. As a consequence, the radar-based QPE would have underestimated the rainfall amount by up to 60\% if they had not been adjusted by rain gauge observations—a technique that is not only affected by other uncertainties, but which is also not feasible in other regions of the country with very sparse rain gauge coverage. Relative calibration techniques, or the assessment of bias from the reflectivity of two radars, has been steadily gaining popularity. Previous studies have demonstrated that reflectivity observations from the Tropical Rainfall Measuring Mission (TRMM) and its successor, the Global Precipitation Measurement (GPM), are accurate enough to serve as a calibration reference for ground radars over low-to-mid-latitudes (± 35 deg for TRMM; ± 65 deg for GPM). Comparing spaceborne radars (SR) and ground radars (GR) requires cautious consideration of differences in measurement geometry and instrument specifications, as well as temporal coincidence. For this purpose, we implement a 3-D volume matching method developed by Schwaller and Morris (2011) and extended by Warren et al. (2018) to 5 years worth of observations from the Subic radar. In this method, only the volumetric intersections of the SR and GR beams are considered. Calibration bias affects reflectivity observations homogeneously across the entire radar domain. Yet, other sources of systematic measurement errors are highly heterogeneous in space, and can either enhance or balance the bias introduced by miscalibration. In order to account for such heterogeneous errors, and thus isolate the calibration bias, we assign a quality index to each matching SR-GR volume, and thus compute the GR calibration bias as a qualityweighted average of reflectivity differences in any sample of matching SR-GR volumes. We exemplify the idea of quality-weighted averaging by using beam blockage fraction (BBF) as a quality variable. Quality-weighted averaging is able to increase the consistency of SR and GR observations by decreasing the standard deviation of the SR-GR differences, and thus increasing the precision of the bias estimates. To extend this framework further, the SR-GR quality-weighted bias estimation is applied to the neighboring Tagaytay radar, but this time focusing on path-integrated attenuation (PIA) as the source of uncertainty. Tagaytay is a C-band radar operating at a lower wavelength and is therefore more affected by attenuation. Applying the same method used for the Subic radar, a time series of calibration bias is also established for the Tagaytay radar. Tagaytay radar sits at a higher altitude than the Subic radar and is surrounded by a gentler terrain, so beam blockage is negligible, especially in the overlapping region. Conversely, Subic radar is largely affected by beam blockage in the overlapping region, but being an SBand radar, attenuation is considered negligible. This coincidentally independent uncertainty contributions of each radar in the region of overlap provides an ideal environment to experiment with the different scenarios of quality filtering when comparing reflectivities from the two ground radars. The standard deviation of the GR-GR differences already decreases if we consider either BBF or PIA to compute the quality index and thus the weights. However, combining them multiplicatively resulted in the largest decrease in standard deviation, suggesting that taking both factors into account increases the consistency between the matched samples. The overlap between the two radars and the instances of the SR passing over the two radars at the same time allows for verification of the SR-GR quality-weighted bias estimation method. In this regard, the consistency between the two ground radars is analyzed before and after bias correction is applied. For cases when all three radars are coincident during a significant rainfall event, the correction of GR reflectivities with calibration bias estimates from SR overpasses dramatically improves the consistency between the two ground radars which have shown incoherent observations before correction. We also show that for cases where adequate SR coverage is unavailable, interpolating the calibration biases using a moving average can be used to correct the GR observations for any point in time to some extent. By using the interpolated biases to correct GR observations, we demonstrate that bias correction reduces the absolute value of the mean difference in most cases, and therefore improves the consistency between the two ground radars. This thesis demonstrates that in general, taking into account systematic sources of uncertainty that are heterogeneous in space (e.g. BBF) and time (e.g. PIA) allows for a more consistent estimation of calibration bias, a homogeneous quantity. The bias still exhibits an unexpected variability in time, which hints that there are still other sources of errors that remain unexplored. Nevertheless, the increase in consistency between SR and GR as well as between the two ground radars, suggests that considering BBF and PIA in a weighted-averaging approach is a step in the right direction. Despite the ample room for improvement, the approach that combines volume matching between radars (either SR-GR or GR-GR) and quality-weighted comparison is readily available for application or further scrutiny. As a step towards reproducibility and transparency in atmospheric science, the 3D matching procedure and the analysis workflows as well as sample data are made available in public repositories. Open-source software such as Python and wradlib are used for all radar data processing in this thesis. This approach towards open science provides both research institutions and weather services with a valuable tool that can be applied to radar calibration, from monitoring to a posteriori correction of archived data.},
  language  = {en}
}
@phdthesis{Damour2019,
  author    = {Damour, Jean-Claude},
  title     = {Hegel und Wittgenstein {\"u}ber den Sinn der Sprache},
  doi       = {10.25932/publishup-43103},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431036},
  school      = {Universit{\"a}t Potsdam},
  pages     = {132},
  year      = {2019},
  abstract  = {The key objectives of this dissertation are to justify the use of dialectic methodology in the realm of the philosophy of language and to conduct a systematic processing of a limited part of this field. In order to explain and determine this approach, which is found rarely, if ever, in contemporary research, I will begin by referring to two philosophical authors: Hegel and Wittgenstein. Although Hegel and Wittgenstein are, prima facie, two authors who have very little in common, the primary supposition of this dissertation regarding the history of ideas is that Hegel's concept of "Spirit" and Wittgenstein's concept of "Form of life" are nevertheless both approaches and the results of philosophical effort that imply the necessity of solving a sceptical challenge. Wittgenstein actually developed an argument in his Philosophical Investigations that has been described as the "rule-following paradox" and has been considered in secondary literature (especially Kripke) as the main tenet of a sceptical argument. Consequently, Wittgenstein's theory of language as developed in Philosophical Investigations has been interpreted by various authors either as a solution to this scepticism or as a sceptical, or "aporetic", text in itself (Brandom). The first section of my dissertation aims to demonstrate that dealing with this paradox does not constitute a full sceptical argument and can be considered as the first moment of a higher form of sceptical challenge, an antinomy. A full sceptical challenge implies both the possibility that the theory corresponding to the unique solution of the paradox, the negation of any explicit normativity ("dispositionalism"), and the negation of the principle of this solution, can be proved. I'll therefore attempt to establish an antinomy of the concept of normativity with respect to the rule of language, similar to Kant's exposure of his cosmological antinomy (thesis cum antithesis). The second aim of my dissertation is to show: that Kant's approach to solving his antinomy is ineffective concerning the antinomy of normativity; that this antinomy implies a confrontation with radical scepticism in a sense that we are committed not to simply challenging or reconsidering some theories, but to engaging in a deep revision of our methodology (This in turn entails a deep revision of the current norms of rationality); that the Hegelian dialectic emerges as the solution to such a radical sceptical challenge, as the true solution to antinomy. A further goal of this dissertation is to use this methodological result to gain a new knowledge of language, consisting of two contradictory moments of cognition that are constructively combined: normativity by means of disposition, and normativity by means of an explicit rule-following. The tangible benefit of such a methodological approach is the possibility of building a systematic philosophy of language that enables the establishment of a dialectical deduction of the moments of the concept of language as moments of the concept of the spirit, in other words, to establish the sense of language. Nonetheless, I must limit myself to exposure to the doctrine of imagination, which encompasses general semiotics and the system of grammar.},
  language  = {de}
}
@phdthesis{Debsharma2019,
  author    = {Debsharma, Tapas},
  title     = {Cellulose derived polymers},
  doi       = {10.25932/publishup-44131},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441312},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 103},
  year      = {2019},
  abstract  = {Plastics, such as polyethylene, polypropylene, and polyethylene terephthalate are part of our everyday lives in the form of packaging, household goods, electrical insulation, etc. These polymers are non-degradable and create many environmental problems and public health concerns. Additionally, these polymers are produced from finite fossils resources. With the continuous utilization of these limited resources, it is important to look towards renewable sources along with biodegradation of the produced polymers, ideally. Although many bio-based polymers are known, such as polylactic acid, polybutylene succinate adipate or polybutylene succinate, none have yet shown the promise of replacing conventional polymers like polyethylene, polypropylene and polyethylene terephthalate. Cellulose is one of the most abundant renewable resources produced in nature. It can be transformed into various small molecules, such as sugars, furans, and levoglucosenone. The aim of this research is to use the cellulose derived molecules for the synthesis of polymers. Acid-treated cellulose was subjected to thermal pyrolysis to obtain levoglucosenone, which was reduced to levoglucosenol. Levoglucosenol was polymerized, for the first time, by ring-opening metathesis polymerization (ROMP) yielding high molar mass polymers of up to ~150 kg/mol. The poly(levoglucosenol) is thermally stable up to ~220 ℃, amorphous, and is exhibiting a relatively high glass transition temperature of ~100 ℃. The poly(levoglucosenol) can be converted to a transparent film, resembling common plastic, and was found to degrade in a moist acidic environment. This means that poly(levoglucosenol) may find its use as an alternative to conventional plastic, for instance, polystyrene. Levoglucosenol was also converted into levoglucosenyl methyl ether, which was polymerized by cationic ring-opening metathesis polymerization (CROP). Polymers were obtained with molar masses up to ~36 kg/mol. These polymers are thermally stable up to ~220 ℃ and are semi-crystalline thermoplastics, having a glass transition temperature of ~35 ℃ and melting transition of 70-100 ℃. Additionally, the polymers underwent cross-linking, hydrogenation and thiol-ene click chemistry.},
  language  = {en}
}
@phdthesis{Desanois2019,
  author    = {Desanois, Louis},
  title     = {On the origin of epithermal Sn-Ag-Zn mineralization at the Pirquitas mine, NW Argentina},
  doi       = {10.25932/publishup-43082},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430822},
  school      = {Universit{\"a}t Potsdam},
  pages     = {104},
  year      = {2019},
  abstract  = {The Central Andes host large reserves of base and precious metals. The region represented, in 2017, an important part of the worldwide mining activity. Three principal types of deposits have been identified and studied: 1) porphyry type deposits extending from central Chile and Argentina to Bolivia, and Northern Peru, 2) iron oxide-copper-gold (IOCG) deposits, extending from central Peru to central Chile, and 3) epithermal tin polymetallic deposits extending from Southern Peru to Northern Argentina, which compose a large part of the deposits of the Bolivian Tin Belt (BTB). Deposits in the BTB can be divided into two major types: (1) tin-tungsten-zinc pluton-related polymetallic deposits, and (2) tin-silver-lead-zinc epithermal polymetallic vein deposits. Mina Pirquitas is a tin-silver-lead-zinc epithermal polymetallic vein deposit, located in north-west Argentina, that used to be one of the most important tin-silver producing mine of the country. It was interpreted to be part of the BTB and it shares similar mineral associations with southern pluton related BTB epithermal deposits. Two major mineralization events related to three pulses of magmatic fluids mixed with meteoric water have been identified. The first event can be divided in two stages: 1) stage I-1 with quartz, pyrite, and cassiterite precipitating from fluids between 233 and 370 °C and salinity between 0 and 7.5 wt\%, corresponding to a first pulse of fluids, and 2) stage I-2 with sphalerite and tin-silver-lead-antimony sulfosalts precipitating from fluids between 213 and 274 °C with salinity up to 10.6 wt\%, corresponding to a new pulse of magmatic fluids in the hydrothermal system. The mineralization event II deposited the richest silver ores at Pirquitas. Event II fluids temperatures and salinities range between 190 and 252 °C and between 0.9 and 4.3 wt\% respectively. This corresponds to the waning supply of magmatic fluids. Noble gas isotopic compositions and concentrations in ore-hosted fluid inclusions demonstrate a significant contribution of magmatic fluids to the Pirquitas mineralization although no intrusive rocks are exposed in the mine area. Lead and sulfur isotopic measurements on ore minerals show that Pirquitas shares a similar signature with southern pluton related polymetallic deposits in the BTB. Furthermore, the major part of the sulfur isotopic values of sulfide and sulfosalt minerals from Pirquitas ranges in the field for sulfur derived from igneous rocks. This suggests that the main contribution of sulfur to the hydrothermal system at Pirquitas is likely to be magma-derived. The precise age of the deposit is still unknown but the results of wolframite dating of 2.9 ± 9.1 Ma and local structural observations suggest that the late mineralization event is younger than 12 Ma.},
  language  = {en}
}
@phdthesis{Doering2019,
  author    = {D{\"o}ring, Matthias},
  title     = {The public encounter},
  doi       = {10.25932/publishup-50227},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-502276},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xi, 115},
  year      = {2019},
  abstract  = {This thesis puts the citizen-state interaction at its center. Building on a comprehensive model incorporating various perspectives on this interaction, I derive selected research gaps. The three articles, comprising this thesis, tackle these gaps. A focal role plays the citizens' administrative literacy, the relevant competences and knowledge necessary to successfully interact with public organizations. The first article elaborates on the different dimensions of administrative literacy and develops a survey instrument to assess these. The second study shows that public employees change their behavior according to the competences that citizens display during public encounters. They treat citizens preferentially that are well prepared and able to persuade them of their application's potential. Thereby, they signal a higher success potential for bureaucratic success criteria which leads to the employees' cream-skimming behavior. The third article examines the dynamics of employees' communication strategies when recovering from a service failure. The study finds that different explanation strategies yield different effects on the client's frustration. While accepting the responsibility and explaining the reasons for a failure alleviates the frustration and anger, refusing the responsibility leads to no or even reinforcing effects on the client's frustration. The results emphasize the different dynamics that characterize the nature of citizen-state interactions and how they establish their short- and long-term outcomes.},
  language  = {en}
}
@phdthesis{Ehrlich2019,
  author    = {Ehrlich, Elias},
  title     = {On the role of trade-offs in predator-prey interactions},
  doi       = {10.25932/publishup-43063},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430631},
  school      = {Universit{\"a}t Potsdam},
  pages     = {192},
  year      = {2019},
  abstract  = {Predation drives coexistence, evolution and population dynamics of species in food webs, and has strong impacts on related ecosystem functions (e.g. primary production). The effect of predation on these processes largely depends on the trade-offs between functional traits in the predator and prey community. Trade-offs between defence against predation and competitive ability, for example, allow for prey speciation and predator-mediated coexistence of prey species with different strategies (defended or competitive), which may stabilize the overall food web dynamics. While the importance of such trade-offs for coexistence is widely known, we lack an understanding and the empirical evidence of how the variety of differently shaped trade-offs at multiple trophic levels affect biodiversity, trait adaptation and biomass dynamics in food webs. Such mechanistic understanding is crucial for predictions and management decisions that aim to maintain biodiversity and the capability of communities to adapt to environmental change ensuring their persistence. In this dissertation, after a general introduction to predator-prey interactions and tradeoffs, I first focus on trade-offs in the prey between qualitatively different types of defence (e.g. camouflage or escape behaviour) and their costs. I show that these different types lead to different patterns of predator-mediated coexistence and population dynamics, by using a simple predator-prey model. In a second step, I elaborate quantitative aspects of trade-offs and demonstrates that the shape of the trade-off curve in combination with trait-fitness relationships strongly affects competition among different prey types: Either specialized species with extreme trait combinations (undefended or completely defended) coexist, or a species with an intermediate defence level dominates. The developed theory on trade-off shapes and coexistence is kept general, allowing for applications apart from defence-competitiveness trade-offs. Thirdly, I tested the theory on trade-off shapes on a long-term field data set of phytoplankton from Lake Constance. The measured concave trade-off between defence and growth governs seasonal trait changes of phytoplankton in response to an altering grazing pressure by zooplankton, and affects the maintenance of trait variation in the community. In a fourth step, I analyse the interplay of different tradeoffs at multiple trophic levels with plankton data of Lake Constance and a corresponding tritrophic food web model. The results show that the trait and biomass dynamics of the different three trophic levels are interrelated in a trophic biomass-trait cascade, leading to unintuitive patterns of trait changes that are reversed in comparison to predictions from bitrophic systems. Finally, in the general discussion, I extract main ideas on trade-offs in multitrophic systems, develop a graphical theory on trade-off-based coexistence, discuss the interplay of intra- and interspecific trade-offs, and end with a management-oriented view on the results of the dissertation, describing how food webs may respond to future global changes, given their trade-offs.},
  language  = {en}
}
@phdthesis{Farhy2019,
  author    = {Farhy, Yael},
  title     = {Universals and particulars in morphology},
  doi       = {10.25932/publishup-47003},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-470033},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VI, 167},
  year      = {2019},
  abstract  = {For many years, psycholinguistic evidence has been predominantly based on findings from native speakers of Indo-European languages, primarily English, thus providing a rather limited perspective into the human language system. In recent years a growing body of experimental research has been devoted to broadening this picture, testing a wide range of speakers and languages, aiming to understanding the factors that lead to variability in linguistic performance. The present dissertation investigates sources of variability within the morphological domain, examining how and to what extent morphological processes and representations are shaped by specific properties of languages and speakers. Firstly, the present work focuses on a less explored language, Hebrew, to investigate how the unique non-concatenative morphological structure of Hebrew, namely a non-linear combination of consonantal roots and vowel patterns to form lexical entries (L-M-D + CiCeC = limed 'teach'), affects morphological processes and representations in the Hebrew lexicon. Secondly, a less investigated population was tested: late learners of a second language. We directly compare native (L1) and non-native (L2) speakers, specifically highly proficient and immersed late learners of Hebrew. Throughout all publications, we have focused on a morphological phenomenon of inflectional classes (called binyanim; singular: binyan), comparing productive (class Piel, e.g., limed 'teach') and unproductive (class Paal, e.g., lamad 'learn') verbal inflectional classes. By using this test case, two psycholinguistic aspects of morphology were examined: (i) how morphological structure affects online recognition of complex words, using masked priming (Publications I and II) and cross-modal priming (Publication III) techniques, and (ii) what type of cues are used when extending morpho-phonological patterns to novel complex forms, a process referred to as morphological generalization, using an elicited production task (Publication IV). The findings obtained in the four manuscripts, either published or under review, provide significant insights into the role of productivity in Hebrew morphological processing and generalization in L1 and L2 speakers. Firstly, the present L1 data revealed a close relationship between productivity of Hebrew verbal classes and recognition process, as revealed in both priming techniques. The consonantal root was accessed only in the productive class (Piel) but not the unproductive class (Paal). Another dissociation between the two classes was revealed in the cross-modal priming, yielding a semantic relatedness effect only for Paal but not Piel primes. These findings are taken to reflect that the Hebrew mental representations display a balance between stored undecomposable unstructured stems (Paal) and decomposed structured stems (Piel), in a similar manner to a typical dual-route architecture, showing that the Hebrew mental lexicon is less unique than previously claimed in psycholinguistic research. The results of the generalization study, however, indicate that there are still substantial differences between inflectional classes of Hebrew and other Indo-European classes, particularly in the type of information they rely on in generalization to novel forms. Hebrew binyan generalization relies more on cues of argument structure and less on phonological cues. Secondly, clear L1/L2 differences were observed in the sensitivity to abstract morphological and morpho-syntactic information during complex word recognition and generalization. While L1 Hebrew speakers were sensitive to the binyan information during recognition, expressed by the contrast in root priming, L2 speakers showed similar root priming effects for both classes, but only when the primes were presented in an infinitive form. A root priming effect was not obtained for primes in a finite form. These patterns are interpreted as evidence for a reduced sensitivity of L2 speakers to morphological information, such as information about inflectional classes, and evidence for processing costs in recognition of forms carrying complex morpho-syntactic information. Reduced reliance on structural information cues was found in production of novel verbal forms, when the L2 group displayed a weaker effect of argument structure for Piel responses, in comparison to the L1 group. Given the L2 results, we suggest that morphological and morphosyntactic information remains challenging for late bilinguals, even at high proficiency levels.},
  language  = {en}
}
@phdthesis{Fuhr2019,
  author    = {Fuhr, Antonie},
  title     = {Eine Hypothese {\"u}ber die Grundlagen von Moral und einige Implikationen},
  doi       = {10.25932/publishup-44309},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-443091},
  school      = {Universit{\"a}t Potsdam},
  pages     = {172},
  year      = {2019},
  abstract  = {In der Dissertationsarbeit mit dem Titel „Eine Hypothese {\"u}ber die Grundlagen von Moral und einige Implikationen" unternimmt die Autorin den Versuch, die anthropologischen Pr{\"a}missen moralischen Handelns herauszuarbeiten. Es wird eine Hypothese aufgestellt und erl{\"a}utert, die behauptet, dass moralisches Handeln nur dann verst{\"a}ndlich wird, wenn der Handelnde erstens die F{\"a}higkeit der Phantasie aufweist, zweitens auf Erfahrungen (mittels seines Ged{\"a}chtnisses) zugreifen kann und durch Konversation mit anderen Personen interagierte und interagiert, denn nur auf der Basis dieser drei Grundlagen von Moral k{\"o}nnen sich diejenigen F{\"a}higkeiten ent¬wickeln, die als Voraussetzungen moralischen Handeln gesehen werden m{\"u}ssen: Selbstbewusstsein, Freiheit, die Entwicklung eines Wir-Gef{\"u}hls, die Genese eines moralischen Ideals und die F{\"a}higkeit, sich im Entscheiden und Handeln nach diesem Ideal richten zu k{\"o}nnen. Außerdem werden in dieser Dissertation einige Implikationen dieser Hypothese auf individueller und zwischenmenschlicher Ebene diskutiert.},
  language  = {de}
}
@phdthesis{Gabriel2019,
  author    = {Gabriel, Christina},
  title     = {Entwicklung neuer St{\"a}rkederivate f{\"u}r die Anwendung als wasserbasierte Filmbildner in Farben und Lacken},
  doi       = {10.25932/publishup-43294},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432942},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XVIII, 160, xxxix, x1},
  year      = {2019},
  abstract  = {In den letzten Jahrzehnten fand auch in der Beschichtungsindustrie ein Umdenken hin zu umweltfreundlicheren Farben und Lacken statt. Allerdings basieren auch neue L{\"o}sungen meist nicht auf Biopolymeren und in einem noch geringeren Anteil auf wasserbasierten Beschichtungssystemen aus nachwachsenden Rohstoffen. Dies stellt den Ankn{\"u}pfungspunkt dieser Arbeit dar, in der untersucht wurde, ob das Biopolymer St{\"a}rke das Potenzial zum wasserbasierten Filmbildner f{\"u}r Farben und Lacke besitzt. Dabei m{\"u}ssen angelehnt an etablierte synthetische Marktprodukte die folgenden Kriterien erf{\"u}llt werden: Die w{\"a}ssrige Dispersion muss mindestens einen 30\%igen Feststoffgehalt haben, bei Raumtemperatur verarbeitet werden k{\"o}nnen und Viskosit{\"a}ten zwischen 10^2-10^3 mPa·s aufweisen. Die finale Beschichtung muss einen geschlossenen Film bilden und sehr gute Haftfestigkeiten zu einer spezifischen Oberfl{\"a}che, in dieser Arbeit Glas, besitzen. Als Grundlage f{\"u}r die Modifizierung der St{\"a}rke wurde eine Kombination von molekularem Abbau und chemischer Funktionalisierung ausgew{\"a}hlt. Da nicht bekannt war, welchen Einfluss die St{\"a}rkeart, die gew{\"a}hlte Abbaureaktion als auch verschiedene Substituenten auf die Dispersionsherstellung und deren Eigenschaften sowie die Beschichtungseigenschaften aus{\"u}ben k{\"o}nnten, wurden die strukturellen Parameter getrennt voneinander untersucht. Das erste Themengebiet beinhaltete den oxidativen Abbau von Kartoffel- und Palerbsenst{\"a}rke mittels des Hypochlorit-Abbaus (OCl-) und des ManOx-Abbaus (H2O2, KMnO4). Mit beiden Abbaureaktionen konnten vergleichbare gewichtsmittlere Molmassen (Mw) von 2·10^5-10^6 g/mol (GPC-MALS) hergestellt werden. Allerdings f{\"u}hrten die gew{\"a}hlten Reaktionsbedingungen beim ManOx-Abbau zur Bildung von Gelpartikeln. Diese lagen im µm-Bereich (DLS und Kryo-REM-Messungen) und hatten zur Folge, dass die ManOx-Proben deutlich erh{\"o}hte Viskosit{\"a}ten (c: 7,5 \%; 9-260 mPa·s) im Vergleich zu den OCl--Proben (4-10 mPa·s) bei scherverd{\"u}nnendem Verhalten besaßen und die Eigenschaften von viskoelastischen Gelen (G' > G'') zeigten. Des Weiteren wiesen sie reduzierte Heißwasserl{\"o}slichkeiten (95 °C, vorrangig: 70-99 \%) auf. Der OCl--Abbau f{\"u}hrte zu hydrophileren (Carboxylgruppengehalt bis zu 6,1 \%; ManOx: bis zu 3,1 \%), nach 95 °C-Behandlung vollst{\"a}ndig wasserl{\"o}slichen abgebauten St{\"a}rken, die ein Newtonsches Fließverhalten mit Eigenschaften einer viskoelastischen Fl{\"u}ssigkeit (G'' > G') hatten. Die OCl--Proben konnten im Vergleich zu den ManOx-Produkten (10-20 \%) zu konzentrierteren Dispersionen (20-40 \%) verarbeitet werden, die gleichzeitig die Einschr{\"a}nkung von anwendungsrelevanten Mw auf < 7·10^5 g/mol zuließen (Konzentration sollte > 30 \% sein). Außerdem f{\"u}hrten nur die OCl--Proben der Kartoffelst{\"a}rke zu transparenten (alle anderen waren opak) geschlossenen Beschichtungsfilmen. Somit hebt sich die Kombination von OCl--Abbau und Kartoffelst{\"a}rke mit Hinblick auf die Endanwendung ab. Das zweite Themengebiet umfasste Untersuchungen zum Einfluss von Ester- und Hydroxyalkylether-Substituenten auf Basis einer industriell abgebauten Kartoffelst{\"a}rke (Mw: 1,2·10^5 g/mol) vor allem auf die Dispersionsherstellung, die rheologischen Eigenschaften der Dispersionen und die Beschichtungseigenschaften in Kombination mit Glassubstraten. Dazu wurden Ester und Ether mit DS/MS-Werten von 0,07-0,91 synthetisiert. Die Derivate konnten zu wasserbasierten Dispersionen mit Konzentrationen von 30-45 \% verarbeitet werden, wobei bei hydrophoberen Modifikaten ein Co-L{\"o}semittel, Diethylenglycolmonobutylether (DEGBE), eingesetzt werden musste. Die Feststoffgehalte sanken dabei f{\"u}r beide Derivatklassen vor allem mit zunehmender Alkylkettenl{\"a}nge. Die anwendungsrelevanten Viskosit{\"a}ten (323-1240 mPa·s) stiegen auf Grund von Wechselwirkungen tendenziell mit DS/MS und Alkylkettenl{\"a}nge an. Hinsichtlich der Beschichtungseigenschaften erwiesen sich die Ester vergleichend zu den Ethern als die bevorzugte Substituentenklasse, da nur die Ester geschlossene, defektfreie und mehrheitlich transparente Beschichtungsfilme bildeten, die exzellente bis sehr gute Haftfestigkeiten (ISO Klasse: 0 und 1) auf Glas besaßen. Die Ether bildeten mehrheitlich br{\"u}chige Filme. Basierend auf der Kombination der Ergebnisse aus L{\"o}semittelaustausch, den rheologischen Untersuchungen und zus{\"a}tzlichen Oberfl{\"a}chenspannungsmessungen (30-61 mN/m) konnte geschlossen werden, dass wahrscheinlich fehlende oder schlechte Haftfestigkeiten vorrangig akkumuliertem Wasser in den Beschichtungsfilmen (visuell: tr{\"u}b oder weiß) geschuldet sind, w{\"a}hrend die Br{\"u}chigkeit vermutlich auf Wechselwirkungen (H-Br{\"u}cken Wechselwirkungen, hydrophobe Wechselwirkungen) zwischen den Polymeren zur{\"u}ckgef{\"u}hrt werden kann. Insgesamt scheint die Kombination aus Kartoffelst{\"a}rke basierend auf dem OCl--Abbau mit Mw < 7·10^5 g/mol und einem Estersubstituenten eine gute Wahl f{\"u}r wasserbasierte Dispersionen mit hohen Feststoffkonzentrationen (> 30 \%), guter Filmbildung und exzellenten Haftungen auf Glas zu sein.},
  language  = {de}
}
@phdthesis{Gawron2019,
  author    = {Gawron, Marian},
  title     = {Towards automated advanced vulnerability analysis},
  doi       = {10.25932/publishup-42635},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426352},
  school      = {Universit{\"a}t Potsdam},
  pages     = {149},
  year      = {2019},
  abstract  = {The identification of vulnerabilities in IT infrastructures is a crucial problem in enhancing the security, because many incidents resulted from already known vulnerabilities, which could have been resolved. Thus, the initial identification of vulnerabilities has to be used to directly resolve the related weaknesses and mitigate attack possibilities. The nature of vulnerability information requires a collection and normalization of the information prior to any utilization, because the information is widely distributed in different sources with their unique formats. Therefore, the comprehensive vulnerability model was defined and different sources have been integrated into one database. Furthermore, different analytic approaches have been designed and implemented into the HPI-VDB, which directly benefit from the comprehensive vulnerability model and especially from the logical preconditions and postconditions. Firstly, different approaches to detect vulnerabilities in both IT systems of average users and corporate networks of large companies are presented. Therefore, the approaches mainly focus on the identification of all installed applications, since it is a fundamental step in the detection. This detection is realized differently depending on the target use-case. Thus, the experience of the user, as well as the layout and possibilities of the target infrastructure are considered. Furthermore, a passive lightweight detection approach was invented that utilizes existing information on corporate networks to identify applications. In addition, two different approaches to represent the results using attack graphs are illustrated in the comparison between traditional attack graphs and a simplistic graph version, which was integrated into the database as well. The implementation of those use-cases for vulnerability information especially considers the usability. Beside the analytic approaches, the high data quality of the vulnerability information had to be achieved and guaranteed. The different problems of receiving incomplete or unreliable information for the vulnerabilities are addressed with different correction mechanisms. The corrections can be carried out with correlation or lookup mechanisms in reliable sources or identifier dictionaries. Furthermore, a machine learning based verification procedure was presented that allows an automatic derivation of important characteristics from the textual description of the vulnerabilities.},
  language  = {en}
}
@phdthesis{Ghani2019,
  author    = {Ghani, Humaad},
  title     = {Structural evolution of the Kohat and Potwar fold and thrust belts of Pakistan},
  doi       = {10.25932/publishup-44077},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-440775},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 121},
  year      = {2019},
  abstract  = {Fold and thrust belts are characteristic features of collisional orogen that grow laterally through time by deforming the upper crust in response to stresses caused by convergence. The deformation propagation in the upper crust is accommodated by shortening along major folds and thrusts. The formation of these structures is influenced by the mechanical strength of d{\´e}collements, basement architecture, presence of preexisting structures and taper of the wedge. These factors control not only the sequence of deformation but also cause differences in the structural style. The Himalayan fold and thrust belt exhibits significant differences in the structural style from east to west. The external zone of the Himalayan fold and thrust belt, also called the Subhimalaya, has been extensively studied to understand the temporal development and differences in the structural style in Bhutan, Nepal and India; however, the Subhimalaya in Pakistan remains poorly studied. The Kohat and Potwar fold and thrust belts (herein called Kohat and Potwar) represent the Subhimalaya in Pakistan. The Main Boundary Thrust (MBT) marks the northern boundary of both Kohat and Potwar, showing that these belts are genetically linked to foreland-vergent deformation within the Himalayan orogen, despite the pronounced contrast in structural style. This contrast becomes more pronounced toward south, where the active strike-slip Kalabagh Fault Zone links with the Kohat and Potwar range fronts, known as the Surghar Range and the Salt Range, respectively. The Surghar and Salt Ranges developed above the Surghar Thrust (SGT) and Main Frontal Thrust (MFT). In order to understand the structural style and spatiotemporal development of the major structures in Kohat and Potwar, I have used structural modeling and low temperature thermochronolgy methods in this study. The structural modeling is based on construction of balanced cross-sections by integrating surface geology, seismic reflection profiles and well data. In order to constrain the timing and magnitude of exhumation, I used apatite (U-Th-Sm)/He (AHe) and apatite fission track (AFT) dating. The results obtained from both methods are combined to document the Paleozoic to Recent history of Kohat and Potwar. The results of this research suggest two major events in the deformation history. The first major deformation event is related to Late Paleozoic rifting associated with the development of the Neo-Tethys Ocean. The second major deformation event is related to the Late Miocene to Pliocene development of the Himalayan fold and thrust belt in the Kohat and Potwar. The Late Paleozoic rifting is deciphered by inverse thermal modelling of detrital AFT and AHe ages from the Salt Range. The process of rifting in this area created normal faulting that resulted in the exhumation/erosion of Early to Middle Paleozoic strata, forming a major unconformity between Cambrian and Permian strata that is exposed today in the Salt Range. The normal faults formed in Late Paleozoic time played an important role in localizing the Miocene-Pliocene deformation in this area. The combination of structural reconstructions and thermochronologic data suggest that deformation initiated at 15±2 Ma on the SGT ramp in the southern part of Kohat. The early movement on the SGT accreted the foreland into the Kohat deforming wedge, forming the range front. The development of the MBT at 12±2 Ma formed the northern boundary of Kohat and Potwar. Deformation propagated south of the MBT in the Kohat on double d{\´e}collements and in the Potwar on a single basal d{\´e}collement. The double d{\´e}collement in the Kohat adopted an active roof-thrust deformation style that resulted in the disharmonic structural style in the upper and lower parts of the stratigraphic section. Incremental shortening resulted in the development of duplexes in the subsurface between two d{\´e}collements and imbrication above the roof thrust. Tectonic thickening caused by duplexes resulted in cooling and exhumation above the roof thrust by removal of a thick sequence of molasse strata. The structural modelling shows that the ramps on which duplexes formed in Kohat continue as tip lines of fault propagation folds in the Potwar. The absence of a double d{\´e}collement in the Potwar resulted in the preservation of a thick sequence of molasse strata there. The temporal data suggest that deformation propagated in-sequence from ~ 8 to 3 Ma in the northern part of Kohat and Potwar; however, internal deformation in the Kohat was more intense, probably required for maintaining a critical taper after a significant load was removed above the upper d{\´e}collement. In the southern part of Potwar, a steeper basement slope (β≥3°) and the presence of salt at the base of the stratigraphic section allowed for the complete preservation of the stratigraphic wedge, showcased by very little internal deformation. Activation of the MFT at ~4 Ma allowed the Salt Range to become the range front of the Potwar. The removal of a large amount of molasse strata above the MFT ramp enhanced the role of salt in shaping the structural style of the Salt Range and Kalabagh Fault Zone. Salt accumulation and migration resulted in the formation of normal faults in both areas. Salt migration in the Kalabagh fault zone has triggered out-of-sequence movement on ramps in the Kohat. The amount of shortening calculated between the MBT and the SGT in Kohat is 75±5 km and between the MBT and the MFT in Potwar is 65±5 km. A comparable amount of shortening is accommodated in the Kohat and Potwar despite their different widths: 70 km Kohat and 150 km Potwar. In summary, this research suggests that deformation switched between different structures during the last ~15 Ma through different modes of fault propagation, resulting in different structural styles and the out-of-sequence development of Kohat and Potwar.},
  language  = {en}
}
@phdthesis{Goktas2019,
  author    = {Goktas, Melis},
  title     = {Coiled coils as molecular force sensors for the extracellular matrix},
  doi       = {10.25932/publishup-42749},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427493},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiv, 124},
  year      = {2019},
  abstract  = {Kraft spielt eine fundamentale Rolle bei der Regulation von biologischen Prozessen. Zellen messen mechanische Eigenschaften der extrazellul{\"a}ren Matrix und benutzen diese Information zur Regulierung ihrer Funktion. Dazu werden im Zytoskelett Kr{\"a}fte generiert und auf extrazellul{\"a}re Rezeptor-Ligand Wechselwirkungen {\"u}bertragen. Obwohl der grundlegende Einfluss von mechanischen Signalen f{\"u}r das Zellschicksal eindeutig belegt ist, sind die auf molekularer Ebene wirkenden Kr{\"a}fte kaum bekannt. Zur Messung dieser Kr{\"a}fte wurden verschiedene molekulare Kraftsensoren entwickelt, die ein mechanisches Inputsignal aufnehmen und in einen optischen Output (Fluoreszenz) umwandeln. Diese Arbeit etabliert einen neuen Kraftsensor-Baustein, der die mechanischen Eigenschaften der extrazellul{\"a}ren Matrix nachbildet. Dieser Baustein basiert auf nat{\"u}rlichen Matrixproteinen, sogenannten coiled coils (CCs), die α-helikale Strukturen im Zytoskelett und der Matrix formen. Eine Serie an CC-Heterodimeren wurde konzipiert und mittels Einzelmolek{\"u}l-Kraftspektroskopie und Molekulardynamik-Simulationen charakterisiert. Es wurde gezeigt, dass eine anliegende Scherkraft die Entfaltung der helikalen Struktur induziert. Die mechanische Stabilit{\"a}t (Separation der CC Helices) wird von der CC L{\"a}nge und der Zuggeschwindigkeit bestimmt. Im Folgenden wurden 2 CCs unterschiedlicher L{\"a}nge als Kraftsensoren verwendet, um die Adh{\"a}sionskr{\"a}fte von Fibroblasten und Endothelzellen zu untersuchen. Diese Kraftsensoren deuten an, dass diese Zelltypen unterschiedlich starke Kr{\"a}ften generieren und mittels Integrin-Rezeptoren auf einen extrazellul{\"a}ren Liganden (RGD-Peptid) {\"u}bertragen. Dieses neue CC-basierte Sensordesign ist ein leistungsstarkes Werkzeug zur Betrachtung zellul{\"a}rer Kraftwahrnehmungsprozesse auf molekularer Ebene, das neue Erkenntnisse {\"u}ber die involvierten Mechanismen und Kr{\"a}fte an der Zell-Matrix-Schnittstelle erm{\"o}glicht. Dar{\"u}ber hinaus wird dieses Sensordesign auch Anwendung bei der Entwicklung mechanisch kontrollierter Biomaterialien finden. Dazu k{\"o}nnen mechanisch charakterisierte, und mit einem Fluoreszenzreporter versehene, CCs in Hydrogele eingef{\"u}gt werden. Dies erlaubt die Untersuchung der Zusammenh{\"a}nge zwischen molekularer und makroskopischer Mechanik und er{\"o}ffnet neue M{\"o}glichkeiten zur Diskriminierung von lokalen und globalen Faktoren, die die zellul{\"a}re Antwort auf mechanische Signale bestimmen.},
  language  = {en}
}
@phdthesis{Gong2019,
  author    = {Gong, Chen Chris},
  title     = {Synchronization of coupled phase oscillators},
  doi       = {10.25932/publishup-48752},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-487522},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xvii, 115},
  year      = {2019},
  abstract  = {Oscillatory systems under weak coupling can be described by the Kuramoto model of phase oscillators. Kuramoto phase oscillators have diverse applications ranging from phenomena such as communication between neurons and collective influences of political opinions, to engineered systems such as Josephson Junctions and synchronized electric power grids. This thesis includes the author's contribution to the theoretical framework of coupled Kuramoto oscillators and to the understanding of non-trivial N-body dynamical systems via their reduced mean-field dynamics. The main content of this thesis is composed of four parts. First, a partially integrable theory of globally coupled identical Kuramoto oscillators is extended to include pure higher-mode coupling. The extended theory is then applied to a non-trivial higher-mode coupled model, which has been found to exhibit asymmetric clustering. Using the developed theory, we could predict a number of features of the asymmetric clustering with only information of the initial state provided. The second part consists of an iterated discrete-map approach to simulate phase dynamics. The proposed map --- a Moebius map --- not only provides fast computation of phase synchronization, it also precisely reflects the underlying group structure of the dynamics. We then compare the iterated-map dynamics and various analogous continuous-time dynamics. We are able to replicate known phenomena such as the synchronization transition of the Kuramoto-Sakaguchi model of oscillators with distributed natural frequencies, and chimera states for identical oscillators under non-local coupling. The third part entails a particular model of repulsively coupled identical Kuramoto-Sakaguchi oscillators under common random forcing, which can be shown to be partially integrable. Via both numerical simulations and theoretical analysis, we determine that such a model cannot exhibit stationary multi-cluster states, contrary to the numerical findings in previous literature. Through further investigation, we find that the multi-clustering states reported previously occur due to the accumulation of discretization errors inherent in the integration algorithms, which introduce higher-mode couplings into the model. As a result, the partial integrability condition is violated. Lastly, we derive the microscopic cross-correlation of globally coupled non-identical Kuramoto oscillators under common fluctuating forcing. The effect of correlation arises naturally in finite populations, due to the non-trivial fluctuations of the meanfield. In an idealized model, we approximate the finite-sized fluctuation by a Gaussian white noise. The analytical approximation qualitatively matches the measurements in numerical experiments, however, due to other periodic components inherent in the fluctuations of the mean-field there still exist significant inconsistencies.},
  language  = {en}
}
@phdthesis{Grafe2019,
  author    = {Grafe, Marianne Erika},
  title     = {Analysis of supramolecular assemblies of NE81, the first lamin protein in a non-metazoan organism},
  doi       = {10.25932/publishup-44180},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-441802},
  school      = {Universit{\"a}t Potsdam},
  pages     = {V, 94},
  year      = {2019},
  abstract  = {Lamine sind Proteine an der inneren Kernh{\"u}lle und bilden zusammen mit verbundenen Proteinen die nukle{\"a}re Lamina. Dieses Netzwerk sorgt f{\"u}r die Stabilit{\"a}t des Zellkerns und unterst{\"u}tzt die Organisation des Zell-Zytoskeletts. Zus{\"a}tzlich sind Lamine und ihre verbundenen Proteine in viele Prozesse wie Genregulation und Zelldifferenzierung involviert. Bis 2012 war der Stand der Forschung, dass nur bei mehrzelligen Organismen eine nukle{\"a}re Lamina zu finden ist. NE81 ist das erste lamin-{\"a}hnliche Protein, das in einem nicht-mehrzelligen Organismus (Dictyostelium discoideum) entdeckt wurde. Es hat viele Eigenschaften und Strukturmerkmale mit Laminen gemeinsam. Dazu z{\"a}hlt der dreiteilige Aufbau des Proteins, eine Phosphorylierungsstelle f{\"u}r ein Zellzyklus-abh{\"a}ngiges Enzym, ein Kernlokalisationssignal, wodurch das Protein in den Kern transportiert wird, sowie eine C-terminale Sequenz zur Verankerung des Proteins in der Kernh{\"u}lle. In dieser Arbeit wurden verschiedene Methoden zur vereinfachten Untersuchung von Laminstrukturen getestet, um zu zeigen, dass sich NE81 wie bereits bekannte Lamin-Proteine verh{\"a}lt und supramolekulare Netzwerke aus Laminfilamenten bildet. Zur Analyse der Struktur supramolekularer Anordnungen wurde das Protein durch Entfernen des Kernlokalisationssignals auf der {\"a}ußeren Kernh{\"u}lle von Dictyostelium gebildet. Die anschließende Untersuchung der Oberfl{\"a}che der Kerne mit einem Rasterelektronenmikroskop zeigte, dass NE81 Strukturen in der Gr{\"o}ße von Laminen bildet, allerdings nicht in regelm{\"a}ßigen filament{\"o}sen Anordnungen. Um die Entstehung der Laminfilamente zu untersuchen, wurde l{\"o}sliches NE81 aus Dictyostelium aufgereinigt und mit verschiedenen mikroskopischen Methoden untersucht. Dabei wurde festgestellt, dass NE81 unter Niedrigsalz-Bedingungen d{\"u}nne, fadenf{\"o}rmige Strukturen und Netzwerke ausbildet, die denen von S{\"a}ugetier-Laminen sehr {\"a}hnlich sind. Die Mutation der Phosphorylierungsstelle von NE81 zu einer imitierenden dauerhaften Phosphorylierung von NE81 in der Zelle, zeigte zun{\"a}chst ein gel{\"o}stes Protein, das {\"u}berraschenderweise unter Blaulichtbestrahlung der Zelle wieder lamin-{\"a}hnliche Anordnungen formte. Die Ergebnisse dieser Arbeit zeigen, dass NE81 echte Laminstrukturen ausbilden kann und hebt Dictyostelium als Nicht-S{\"a}ugetier-Modellorganismus mit einer gut charakterisierten Kernh{\"u}lle, mit allen relevanten, aus tierischen Zellen bekannten Proteinen, hervor.},
  language  = {en}
}
@phdthesis{Grishina2019,
  author    = {Grishina, Yulia},
  title     = {Assessing the applicability of annotation projection methods for coreference relations},
  doi       = {10.25932/publishup-42537},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-425378},
  school      = {Universit{\"a}t Potsdam},
  pages     = {viii, 198},
  year      = {2019},
  abstract  = {The main goal of this thesis is to explore the feasibility of using cross-lingual annotation projection as a method of alleviating the task of manual coreference annotation. To reach our goal, we build a first trilingual parallel coreference corpus that encompasses multiple genres. For the annotation of the corpus, we develop common coreference annotation guidelines that are applicable to three languages (English, German, Russian) and include a novel domain-independent typology of bridging relations as well as state-of-the-art near-identity categories. Thereafter, we design and perform several annotation projection experiments. In the first experiment, we implement a direct projection method with only one source language. Our results indicate that, already in a knowledge-lean scenario, our projection approach is superior to the most closely related work of Postolache et al. (2006). Since the quality of the resulting annotations is to a high degree dependent on the word alignment, we demonstrate how using limited syntactic information helps to further improve mention extraction on the target side. As a next step, in our second experiment, we show how exploiting two source languages helps to improve the quality of target annotations for both language pairs by concatenating annotations projected from two source languages. Finally, we assess the projection quality in a fully automatic scenario (using automatically produced source annotations), and propose a pilot experiment on manual projection of bridging pairs. For each of the experiments, we carry out an in-depth error analysis, and we conclude that noisy word alignments, translation divergences and morphological and syntactic differences between languages are responsible for projection errors. We systematically compare and evaluate our projection methods, and we investigate the errors both qualitatively and quantitatively in order to identify problematic cases. Finally, we discuss the applicability of our method to coreference annotations and propose several avenues of future research.},
  language  = {en}
}
@phdthesis{Guislain2019,
  author    = {Guislain, Alexis},
  title     = {Eco-physiological consequences of fluctuating light on phytoplankton},
  doi       = {10.25932/publishup-46927},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-469272},
  school      = {Universit{\"a}t Potsdam},
  pages     = {161},
  year      = {2019},
  abstract  = {Phytoplankton growth depends not only on the mean intensity but also on the dynamics of the light supply. The nonlinear light-dependency of growth is characterized by a small number of basic parameters: the compensation light intensity PARcompμ, where production and losses are balanced, the growth efficiency at sub-saturating light αµ, and the maximum growth rate at saturating light µmax. In surface mixed layers, phytoplankton may rapidly move between high light intensities and almost darkness. Because of the different frequency distribution of light and/or acclimation processes, the light-dependency of growth may differ between constant and fluctuating light. Very few studies measured growth under fluctuating light at a sufficient number of mean light intensities to estimate the parameters of the growth-irradiance relationship. Hence, the influence of light dynamics on µmax, αµ and PARcompμ are still largely unknown. By extension, accurate modelling predictions of phytoplankton development under fluctuating light exposure remain difficult to make. This PhD thesis does not intend to directly extrapolate few experimental results to aquatic systems - but rather improving the mechanistic understanding of the variation of the light-dependency of growth under light fluctuations and effects on phytoplankton development. In Lake TaiHu and at the Three Gorges Reservoir (China), we incubated phytoplankton communities in bottles placed either at fixed depths or moved vertically through the water column to mimic vertical mixing. Phytoplankton at fixed depths received only the diurnal changes in light (defined as constant light regime), while phytoplankton received rapidly fluctuating light by superimposing the vertical light gradient on the natural sinusoidal diurnal sunlight. The vertically moved samples followed a circular movement with 20 min per revolution, replicating to some extent the full overturn of typical Langmuir cells. Growth, photosynthesis, oxygen production and respiration of communities (at Lake TaiHu) were measured. To complete these investigations, a physiological experiment was performed in the laboratory on a toxic strain of Microcystis aeruginosa (FACBH 1322) incubated under 20 min period fluctuating light. Here, we measured electron transport rates and net oxygen production at a much higher time resolution (single minute timescale). The present PhD thesis provides evidence for substantial effects of fluctuating light on the eco-physiology of phytoplankton. Both experiments performed under semi-natural conditions in Lake TaiHu and at the Three Gorges Reservoir gave similar results. The significant decline in community growth efficiencies αµ under fluctuating light was caused for a great share by different frequency distribution of light intensities that shortened the effective daylength for production. The remaining gap in community αµ was attributed to species-specific photoacclimation mechanisms and to light-dependent respiratory losses. In contrast, community maximal growth rates µmax were similar between incubations at constant and fluctuating light. At daily growth saturating light supply, differences in losses for biosynthesis between the two light regimes were observed. Phytoplankton experiencing constant light suffered photo-inhibition - leading to photosynthesis foregone and additional respiratory costs for photosystems repair. On the contrary, intermittent exposure to low and high light intensities prevented photo-inhibition of mixed algae but forced them to develop alternative light strategy. They better harvested and exploited surface irradiance by enhancing their photosynthesis. In the laboratory, we showed that Microcystis aeruginosa increased its oxygen consumption by dark respiration in the light few minutes only after exposure to increasing light intensities. More, we proved that within a simulated Langmuir cell, the net production at saturating light and the compensation light intensity for production at limiting light are positively related. These results are best explained by an accumulation of photosynthetic products at increasing irradiance and mobilization of these fresh resources by rapid enhancement of dark respiration for maintenance and biosynthesis at decreasing irradiance. At the daily timescale, we showed that the enhancement of photosynthesis at high irradiance for biosynthesis of species increased their maintenance respiratory costs at limiting light. Species-specific growth at saturating light µmax and compensation light intensity for growth PARcompμ of species incubated in Lake TaiHu were positively related. Because of this species-specific physiological tradeoff, species displayed different light affinities to limiting and saturating light - thereby exhibiting a gleaner-opportunist tradeoff. In Lake TaiHu, we showed that inter-specific differences in light acquisition traits (µmax and PARcompμ) allowed coexis¬tence of species on a gradient of constant light while avoiding competitive exclusion. More interestingly we demonstrated for the first time that vertical mixing (inducing fluctuating light supply for phytoplankton) may alter or even reverse the light utilization strategies of species within couple of days. The intra-specific variation in traits under fluctuating light increased the niche space for acclimated species, precluding competitive exclusion. Overall, this PhD thesis contributes to a better understanding of phytoplankton eco-physiology under fluctuating light supply. This work could enhance the quality of predictions of phytoplankton development under certain weather conditions or climate change scenarios.},
  language  = {en}
}
@phdthesis{Hanschmann2019,
  author    = {Hanschmann, Raffael Tino},
  title     = {Stalling the engine? EU climate politics after the 'Great Recession'},
  doi       = {10.25932/publishup-44044},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-440441},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XXVIII, 303},
  year      = {2019},
  abstract  = {This dissertation investigates the impact of the economic and fiscal crisis starting in 2008 on EU climate policy-making. While the overall number of adopted greenhouse gas emission reduction policies declined in the crisis aftermath, EU lawmakers decided to introduce new or tighten existing regulations in some important policy domains. Existing knowledge about the crisis impact on EU legislative decision-making cannot explain these inconsistencies. In response, this study develops an actor-centred conceptual framework based on rational choice institutionalism that provides a micro-level link to explain how economic crises translate into altered policy-making patterns. The core theoretical argument draws on redistributive conflicts, arguing that tensions between 'beneficiaries' and 'losers' of a regulatory initiative intensify during economic crises and spill over to the policy domain. To test this hypothesis and using social network analysis, this study analyses policy processes in three case studies: The introduction of carbon dioxide emission limits for passenger cars, the expansion of the EU Emissions Trading System to aviation, and the introduction of a regulatory framework for biofuels. The key finding is that an economic shock causes EU policy domains to polarise politically, resulting in intensified conflict and more difficult decision-making. The results also show that this process of political polarisation roots in the industry that is the subject of the regulation, and that intergovernmental bargaining among member states becomes more important, but also more difficult in times of crisis.},
  language  = {en}
}
@phdthesis{He2019,
  author    = {He, Hai},
  title     = {Exploring and engineering formaldehyde assimilation},
  doi       = {10.25932/publishup-47386},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-473867},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vi, 105},
  year      = {2019},
  abstract  = {Increasing concerns regarding the environmental impact of our chemical production have shifted attention towards possibilities for sustainable biotechnology. One-carbon (C1) compounds, including methane, methanol, formate and CO, are promising feedstocks for future bioindustry. CO2 is another interesting feedstock, as it can also be transformed using renewable energy to other C1 feedstocks for use. While formaldehyde is not suitable as a feedstock due to its high toxicity, it is a central intermediate in the process of C1 assimilation. This thesis explores formaldehyde metabolism and aims to engineer formaldehyde assimilation in the model organism Escherichia coli for the future C1-based bioindustry. The first chapter of the thesis aims to establish growth of E. coli on formaldehyde via the most efficient naturally occurring route, the ribulose monophosphate pathway. Linear variants of the pathway were constructed in multiple-gene knockouts strains, coupling E. coli growth to the activities of the key enzymes of the pathway. Formaldehyde-dependent growth was achieved in rationally designed strains. In the final strain, the synthetic pathway provides the cell with almost all biomass and energy requirements. In the second chapter, taking advantage of the unique feature of its reactivity, formaldehyde assimilation via condensation with glycine and pyruvate by two promiscuous aldolases was explored. Facilitated by these two reactions, the newly designed homoserine cycle is expected to support higher yields of a wide array of products than its counterparts. By dividing the pathway into segments and coupling them to the growth of dedicated strains, all pathway reactions were demonstrated to be sufficiently active. The work paves a way for future implementation of a highly efficient route for C1 feedstocks into commodity chemicals. In the third chapter, the in vivo rate of the spontaneous formaldehyde tetrahydrofolate condensation to methylene-tetrahydrofolate was assessed in order to evaluate its applicability as a biotechnological process. Tested within an E. coli strain deleted in essential genes for native methylene-tetrahydrofolate biosynthesis, the reaction was shown to support the production of this essential intermediate. However, only low growth rates were observed and only at high formaldehyde concentrations. Computational analysis dependent on in vivo evidence from this strain deduced the slow rate of this spontaneous reaction, thus ruling out its substantial contribution to growth on C1 feedstocks. The reactivity of formaldehyde makes it highly toxic. In the last chapter, the formation of thioproline, the condensation product of cysteine and formaldehyde, was confirmed to contribute this toxicity effect. Xaa-Pro aminopeptidase (PepP), which genetically links with folate metabolism, was shown to hydrolyze thioproline-containing peptides. Deleting pepP increased strain sensitivity to formaldehyde, pointing towards the toxicity of thioproline-containing peptides and the importance of their removal. The characterization in this study could be useful in handling this toxic intermediate. Overall, this thesis identified challenges related to formaldehyde metabolism and provided novel solutions towards a future bioindustry based on sustainable C1 feedstocks in which formaldehyde serves as a key intermediate.},
  language  = {en}
}
@phdthesis{Herrmann2019,
  author    = {Herrmann, Johannes},
  title     = {The mechanical behavior of shales},
  doi       = {10.25932/publishup-42968},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429683},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIII, 156},
  year      = {2019},
  abstract  = {The thesis comprises three experimental studies, which were carried out to unravel the short- as well as the long-term mechanical properties of shale rocks. Short-term mechanical properties such as compressive strength and Young's modulus were taken from recorded stress-strain curves of constant strain rate tests. Long-term mechanical properties are represented by the time- dependent creep behavior of shales. This was obtained from constant stress experiments, where the test duration ranged from a couple minutes up to two weeks. A profound knowledge of the mechanical behavior of shales is crucial to reliably estimate the potential of a shale reservoir for an economical and sustainable extraction of hydrocarbons (HC). In addition, healing of clay-rich forming cap rocks involving creep and compaction is important for underground storage of carbon dioxide and nuclear waste. Chapter 1 introduces general aspects of the research topic at hand and highlights the motivation for conducting this study. At present, a shift from energy recovered from conventional resources e.g., coal towards energy provided by renewable resources such as wind or water is a big challenge. Gas recovered from unconventional reservoirs (shale plays) is considered a potential bridge technology. In Chapter 2, short-term mechanical properties of two European mature shale rocks are presented, which were determined from constant strain rate experiments performed at ambient and in situ deformation conditions (confining pressure, pc ≤ 100 MPa, temperature, T ≤ 125 °C, representing pc, T - conditions at < 4 km depth) using a Paterson- type gas deformation apparatus. The investigated shales were mainly from drill core material of Posidonia (Germany) shale and weathered material of Bowland (United Kingdom) shale. The results are compared with mechanical properties of North American shales. Triaxial compression tests performed perpendicular to bedding revealed semibrittle deformation behavior of Posidonia shale with pronounced inelastic deformation. This is in contrast to Bowland shale samples that deformed brittle and displayed predominantly elastic deformation. The static Young's modulus, E, and triaxial compressive strength, σTCS, determined from recorded stress-strain curves strongly depended on the applied confining pressure and sample composition, whereas the influence of temperature and strain rate on E and σTCS was minor. Shales with larger amounts of weak minerals (clay, mica, total organic carbon) yielded decreasing E and σTCS. This may be related to a shift from deformation supported by a load-bearing framework of hard phases (e.g., quartz) towards deformation of interconnected weak minerals, particularly for higher fractions of about 25 - 30 vol\% weak phases. Comparing mechanical properties determined at reservoir conditions with mechanical data applying effective medium theories revealed that E and σTCS of Posidonia and Bowland shale are close to the lower (Reuss) bound. Brittleness B is often quoted as a measure indicating the response of a shale formation to stimulation and economic production. The brittleness, B, of Posidonia and Bowland shale, estimated from E, is in good agreement with the experimental results. This correlation may be useful to predict B from sonic logs, from which the (dynamic) Young's modulus can be retrieved. Chapter 3 presents a study of the long-term creep properties of an immature Posidonia shale. Constant stress experiments (σ = const.) were performed at elevated confining pressures (pc = 50 - 200 MPa) and temperatures (T = 50 - 200 °C) to simulate reservoir pc, T - conditions. The Posidonia shale samples were acquired from a quarry in South Germany. At stresses below ≈ 84 \% compressive strength of Posidonia shale, at high temperature and low confining pressure, samples showed pronounced transient (primary) creep with high deformation rates in the semibrittle regime. Sample deformation was mainly accommodated by creep of weak sample constituents and pore space reduction. An empirical power law relation between strain and time, which also accounts for the influence of pc, T and σ on creep strain was formulated to describe the primary creep phase. Extrapolation of the results to a creep period of several years, which is the typical time interval for a large production decline, suggest that fracture closure is unlikely at low stresses. At high stresses as expected for example at the contact between the fracture surfaces and proppants added during stimulation measures, subcritical crack growth may lead to secondary and tertiary creep. An empirical power law is suggested to describe secondary creep of shale rocks as a function of stress, pressure and temperature. The predicted closure rates agree with typical production decline curves recorded during the extraction of hydrocarbons. At the investigated conditions, the creep behavior of Posidonia shale was found to correlate with brittleness, calculated from sample composition. In Chapter 4 the creep properties of mature Posidonia and Bowland shales are presented. The observed long-term creep behavior is compared to the short-term behavior determined in Chapter 2. Creep experiments were performed at simulated reservoir conditions of pc = 50 - 115 MPa and T = 75 - 150 °C. Similar to the mechanical response of immature Posidonia shale samples investigated in Chapter 3, creep strain rates of mature Bowland and Posidonia shales were enhanced with increasing stress and temperature and decreasing confining pressures. Depending on applied deformation conditions, samples displayed either only a primary (decelerating) or in addition also a secondary (quasi-steady state) and subsequently a tertiary (accelerating) creep phase before failure. At the same deformation conditions, creep strain of Posidonia shale, which is rich in weak constituents, is tremendously higher than of quartz-rich Bowland shale. Typically, primary creep strain is again mostly accommodated by deformation of weak minerals and local pore space reduction. At the onset of tertiary creep most of the deformation was accommodated by micro crack growth. A power law was used to characterize the primary creep phase of Posidonia and Bowland shale. Primary creep strain of shale rocks is inversely correlated to triaxial compressive strength and brittleness, as described in Chapter 2. Chapter 5 provides a synthesis of the experimental findings and summarizes the major results of the studies presented in Chapters 2 - 4 and potential applications in the Exploration \& Production industry. Chapter 6 gives a brief outlook on potential future experimental research that would help to further improve our understanding of processes leading to fracture closure involving proppant embedment in unconventional shale gas reservoirs. Such insights may allow to improve stimulation techniques aimed at maintaining economical extraction of hydrocarbons over several years.},
  language  = {en}
}
@phdthesis{Hoang2019,
  author    = {Hoang, Yen},
  title     = {De novo binning strategy to analyze and visualize multi-dimensional cytometric data},
  doi       = {10.25932/publishup-44307},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-443078},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vii, 81, xxxii},
  year      = {2019},
  abstract  = {Since half a century, cytometry has been a major scientific discipline in the field of cytomics - the study of system's biology at single cell level. It enables the investigation of physiological processes, functional characteristics and rare events with proteins by analysing multiple parameters on an individual cell basis. In the last decade, mass cytometry has been established which increased the parallel measurement to up to 50 proteins. This has shifted the analysis strategy from conventional consecutive manual gates towards multi-dimensional data processing. Novel algorithms have been developed to tackle these high-dimensional protein combinations in the data. They are mainly based on clustering or non-linear dimension reduction techniques, or both, often combined with an upstream downsampling procedure. However, these tools have obstacles either in comprehensible interpretability, reproducibility, computational complexity or in comparability between samples and groups. To address this bottleneck, a reproducible, semi-automated cytometric data mining workflow PRI (pattern recognition of immune cells) is proposed which combines three main steps: i) data preparation and storage; ii) bin-based combinatorial variable engineering of three protein markers, the so called triploTs, and subsequent sectioning of these triploTs in four parts; and iii) deployment of a data-driven supervised learning algorithm, the cross-validated elastic-net regularized logistic regression, with these triploT sections as input variables. As a result, the selected variables from the models are ranked by their prevalence, which potentially have discriminative value. The purpose is to significantly facilitate the identification of meaningful subpopulations, which are most distinguish between two groups. The proposed workflow PRI is exemplified by a recently published public mass cytometry data set. The authors found a T cell subpopulation which is discriminative between effective and ineffective treatment of breast carcinomas in mice. With PRI, that subpopulation was not only validated, but was further narrowed down as a particular Th1 cell population. Moreover, additional insights of combinatorial protein expressions are revealed in a traceable manner. An essential element in the workflow is the reproducible variable engineering. These variables serve as basis for a clearly interpretable visualization, for a structured variable exploration and as input layers in neural network constructs. PRI facilitates the determination of marker levels in a semi-continuous manner. Jointly with the combinatorial display, it allows a straightforward observation of correlating patterns, and thus, the dominant expressed markers and cell hierarchies. Furthermore, it enables the identification and complex characterization of discriminating subpopulations due to its reproducible and pseudo-multi-parametric pattern presentation. This endorses its applicability as a tool for unbiased investigations on cell subsets within multi-dimensional cytometric data sets.},
  language  = {en}
}
@phdthesis{Hoffmann2019,
  author    = {Hoffmann, Mathias},
  title     = {Improving measurement and modelling approaches of the closed chamber method to better assess dynamics and drivers of carbon based greenhouse gas emissions},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-421302},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xx, 204, xxix},
  year      = {2019},
  abstract  = {The trace gases CO2 and CH4 pertain to the most relevant greenhouse gases and are important exchange fluxes of the global carbon (C) cycle. Their atmospheric quantity increased significantly as a result of the intensification of anthropogenic activities, such as especially land-use and land-use change, since the mid of the 18th century. To mitigate global climate change and ensure food security, land-use systems need to be developed, which favor reduced trace gas emissions and a sustainable soil carbon management. This requires the accurate and precise quantification of the influence of land-use and land-use change on CO2 and CH4 emissions. A common method to determine the trace gas dynamics and C sink or source function of a particular ecosystem is the closed chamber method. This method is often used assuming that accuracy and precision are high enough to determine differences in C gas emissions for e.g., treatment comparisons or different ecosystem components. However, the broad range of different chamber designs, related operational procedures and data-processing strategies which are described in the scientific literature contribute to the overall uncertainty of closed chamber-based emission estimates. Hence, the outcomes of meta-analyses are limited, since these methodical differences hamper the comparability between studies. Thus, a standardization of closed chamber data acquisition and processing is much-needed. Within this thesis, a set of case studies were performed to: (I) develop standardized routines for an unbiased data acquisition and processing, with the aim of providing traceable, reproducible and comparable closed chamber based C emission estimates; (II) validate those routines by comparing C emissions derived using closed chambers with independent C emission estimates; and (III) reveal processes driving the spatio-temporal dynamics of C emissions by developing (data processing based) flux separation approaches. The case studies showed: (I) the importance to test chamber designs under field conditions for an appropriate sealing integrity and to ensure an unbiased flux measurement. Compared to the sealing integrity, the use of a pressure vent and fan was of minor importance, affecting mainly measurement precision; (II) that the developed standardized data processing routines proved to be a powerful and flexible tool to estimate C gas emissions and that this tool can be successfully applied on a broad range of flux data sets from very different ecosystem; (III) that automatic chamber measurements display temporal dynamics of CO2 and CH4 fluxes very well and most importantly, that they accurately detect small-scale spatial differences in the development of soil C when validated against repeated soil inventories; and (IV) that a simple algorithm to separate CH4 fluxes into ebullition and diffusion improves the identification of environmental drivers, which allows for an accurate gap-filling of measured CH4 fluxes. Overall, the proposed standardized data acquisition and processing routines strongly improved the detection accuracy and precision of source/sink patterns of gaseous C emissions. Hence, future studies, which consider the recommended improvements, will deliver valuable new data and insights to broaden our understanding of spatio-temporal C gas dynamics, their particular environmental drivers and underlying processes.},
  language  = {en}
}
@phdthesis{Hornick2019,
  author    = {Hornick, Thomas},
  title     = {Impact of climate change effects on diversity and function of pelagic heterotrophic bacteria studied in large-scale mesocosm facilities},
  doi       = {10.25932/publishup-42893},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428936},
  school      = {Universit{\"a}t Potsdam},
  pages     = {199},
  year      = {2019},
  abstract  = {Seit der Industriellen Revolution steigt die Konzentration von Kohlenstoffdioxid (CO2) und anderen Treibhausgasen in der Erdatmosph{\"a}re stetig an, wodurch wesentliche Prozesse im Erdsystem beeinflusst werden. Dies wird mit dem Begriff „Klimawandel" umschrieben. Aquatische {\"O}kosysteme sind sehr stark davon betroffen, da sie als Integral vieler Prozesse in einer Landschaft fungieren. Ziel dieser Doktorarbeit war zu bestimmen, wie verschiedene Auswirkungen des Klimawandels die Gemeinschaftsstruktur und Aktivit{\"a}t von heterotrophen Bakterien in Gew{\"a}ssern ver{\"a}ndert, welche eine zentrale Rolle bei biogeochemischen Prozessen einnehmen. Diese Arbeit konzentriert sich auf zwei Aspekte des Klimawandels: (1) Ozeane nehmen einen Großteil des atmosph{\"a}rischen CO2 auf, welches im Meerwasser das chemische Gleichgewicht des Karbonatsystems verschiebt („Ozeanversauerung"). (2) Durch kontinuierlichen Anstieg der Erdoberfl{\"a}chentemperatur werden Ver{\"a}nderungen im Klimasystem der Erde vorhergesagt, welche u. a. die H{\"a}ufigkeit und Heftigkeit von episodischen Wetterereignissen (z.B. St{\"u}rme) verst{\"a}rken wird. Insbesondere Sommer-St{\"u}rme sind dabei in der Lage die sommerliche Temperaturschichtung der Wassers{\"a}ule in Seen zu zerst{\"o}ren. Beide Effekte des Klimawandels k{\"o}nnen weitreichende Auswirkungen auf Wasserchemie/-physik sowie die Verteilung von Organismen haben, was mittels Mesokosmen simuliert wurde. Dabei untersuchten wir den Einfluss der Ozeanversauerung auf heterotrophe bakterielle Prozesse in der Ostsee bei geringen Konzentrationen an gel{\"o}sten N{\"a}hrstoffen. Unsere Ergebnisse zeigen, dass Ozeanversauerungseffekte in Kombination mit N{\"a}hrstofflimitation indirekt das Wachstum von heterotrophen Bakterien durch ver{\"a}nderte trophische Interaktionen beeinflussen k{\"o}nnen und potentiell zu einer Erh{\"o}hung der Autotrophie des {\"O}kosystems f{\"u}hren. In einer weiteren Studie analysierten wir, wie Ozeanversauerung die Umsetzung und Qualit{\"a}t gel{\"o}sten organischen Materials (DOM) durch heterotrophe Bakterien beeinflussen kann. Die Ergebnisse weisen jedoch darauf hin, dass {\"A}nderungen in der DOM-Qualit{\"a}t durch heterotrophe bakterielle Prozesse mit zunehmender Ozeanversauerung unwahrscheinlich sind. Desweiteren wurde der Einfluss eines starken Sommer-Sturmes auf den stratifizierten, oligotroph-mesotrophen Stechlinsee simuliert. Mittels oberfl{\"a}chlicher Durchmischung in Mesokosmen wurde die bestehende Thermokline zerst{\"o}rt und die durchmischte Oberfl{\"a}chenwasserschicht vergr{\"o}ßert. Dies {\"a}nderte die physikalischen und chemischen Gradienten innerhalb der Wassers{\"a}ule. Effekte der Einmischung von Tiefenwasser {\"a}nderten in der Folge die Zusammensetzung der bakteriellen Gemeinschaftsstruktur und stimulierten das Wachstum filament{\"o}ser Cyanobakterien, die zu einer Cyanobakterien-Bl{\"u}te f{\"u}hrte und so maßgeblich die metabolischen Prozesse von heterotrophen Bakterien bestimmte. Unsere Studie gibt ein mechanistisches Verst{\"a}ndnis, wie Sommer-St{\"u}rme bakterielle Gemeinschaften und Prozesse f{\"u}r l{\"a}ngere Zeit w{\"a}hrend der sommerlichen Stratifizierung beeinflussen k{\"o}nnen. Die in dieser Arbeit pr{\"a}sentierten Ergebnisse zeigen Ver{\"a}nderungen bakterieller Gemeinschaften und Prozesse, welche mit dem einhergehenden Klimawandel erwartet werden k{\"o}nnen. Diese sollten bei Beurteilung klimarelevanter Fragen hinsichtlich eines zuk{\"u}nftigen Gew{\"a}sser-managements Ber{\"u}cksichtigung finden.},
  language  = {en}
}
@phdthesis{JadhavSudam2019,
  author    = {Jadhav Sudam, Sagar},
  title     = {Metabolic regulation and key genes of tomato secondary metabolism},
  doi       = {10.25932/publishup-42447},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-424478},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 149},
  year      = {2019},
  abstract  = {Domestication syndrome has resulted in the large loss of genetic variation of crop plants. Because of such genetic loss, productivity of various beneficial secondary (specialized) metabolites that protect against abiotic/biotic stresses, has been narrowed in many domesticated crops. Many key regulators or structural genes of secondary metabolic pathways in the domesticated as well as wild tomatoes are still largely unknown. In recent studies, metabolic quantitative trait loci (mQTL) analysis using the population of introgression lines (ILs), each containing a single introgression from Solanum pennellii (wild tomato) in the genetic background of domesticated tomato (M82, Solanum lycopersicum), has been used for investigation of metabolic regulation and key genes involved in both primary and secondary metabolism. In this thesis, three research projects, i) understanding of metabolic linkage between branched chain amino acids (BCAAs) and secondary metabolism using antisense lines of BCAAs metabolic genes, ii) investigation of novel key genes involved in tomato secondary metabolism and fruit ripening, iii) mapping of drought stress responsive mQTLs in tomato, are presented and discussed. In the first part, metabolic linkage between leucine and secondary metabolism is investigated by analyzing antisense lines of four key genes (ketol-acid reductoisomerase, KARI; dihydroxy-acid dehydratase, DHAD; isopropylmalate dehydratase, IPMD and branched chain aminotransferases1, BCAT1) found previously in mQTL of leucine contents. Obtained results indicate that KARI might be a rate limiting enzyme for iC5 acyl-sucrose synthesis in young leaf but not in red ripe fruits. By integrating obtained results with previous reports, inductive metabolic linkage between BCAAs and other secondary metabolic pathways at DHAD transcriptional levels in fruit is proposed. In the second part, candidate genes that are involved in secondary metabolism and fruit ripening in tomato were found by the approach of expression quantitative trait loci (eQTL) analysis. To predict functions of those candidate genes, functional validation by virus induced gene silencing and transient overexpression were performed. Results obtained by analyzing T0 overexpression and artificial miRNA lines for some of those candidates confirm their predicted functions, for example involved in fruit ripening (WD40, Solyc04g005020) and iC5 acyl-sucrose synthesis (P450, Solyc03g111940). In the third part, mapping of drought stress responsive mQTLs was performed using 57 S. pennellii ILs population. Evaluation of genetic architecture of mQTL analysis resulted in identifying drought responsive ILs (11-2, 8-3-1, 10-1-1 and 3-1). Location of well characterized regulators in these ILs helped to filter potential new key genes involved in drought stress tolerance. Obtained results suggests us our approaches could be viable for narrowing down potential candidates involved in creating interspecific variation in secondary metabolite content and at the level of fruit ripening.},
  language  = {en}
}
@phdthesis{Jakobs2019,
  author    = {Jakobs, Friedrich},
  title     = {Dubrovin-rings and their connection to Hughes-free skew fields of fractions},
  doi       = {10.25932/publishup-43556},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-435561},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 62},
  year      = {2019},
  abstract  = {One method of embedding groups into skew fields was introduced by A. I. Mal'tsev and B. H. Neumann (cf. [18, 19]). If G is an ordered group and F is a skew field, the set F((G)) of formal power series over F in G with well-ordered support forms a skew field into which the group ring F[G] can be embedded. Unfortunately it is not suficient that G is left-ordered since F((G)) is only an F-vector space in this case as there is no natural way to define a multiplication on F((G)). One way to extend the original idea onto left-ordered groups is to examine the endomorphism ring of F((G)) as explored by N. I. Dubrovin (cf. [5, 6]). It is possible to embed any crossed product ring F[G; η, σ] into the endomorphism ring of F((G)) such that each non-zero element of F[G; η, σ] defines an automorphism of F((G)) (cf. [5, 10]). Thus, the rational closure of F[G; η, σ] in the endomorphism ring of F((G)), which we will call the Dubrovin-ring of F[G; η, σ], is a potential candidate for a skew field of fractions of F[G; η, σ]. The methods of N. I. Dubrovin allowed to show that specific classes of groups can be embedded into a skew field. For example, N. I. Dubrovin contrived some special criteria, which are applicable on the universal covering group of SL(2, R). These methods have also been explored by J. Gr{\"a}ter and R. P. Sperner (cf. [10]) as well as N.H. Halimi and T. Ito (cf. [11]). Furthermore, it is of interest to know if skew fields of fractions are unique. For example, left and right Ore domains have unique skew fields of fractions (cf. [2]). This is not the general case as for example the free group with 2 generators can be embedded into non-isomorphic skew fields of fractions (cf. [12]). It seems likely that Ore domains are the most general case for which unique skew fields of fractions exist. One approach to gain uniqueness is to restrict the search to skew fields of fractions with additional properties. I. Hughes has defined skew fields of fractions of crossed product rings F[G; η, σ] with locally indicable G which fulfill a special condition. These are called Hughes-free skew fields of fractions and I. Hughes has proven that they are unique if they exist [13, 14]. This thesis will connect the ideas of N. I. Dubrovin and I. Hughes. The first chapter contains the basic terminology and concepts used in this thesis. We present methods provided by N. I. Dubrovin such as the complexity of elements in rational closures and special properties of endomorphisms of the vector space of formal power series F((G)). To combine the ideas of N.I. Dubrovin and I. Hughes we introduce Conradian left-ordered groups of maximal rank and examine their connection to locally indicable groups. Furthermore we provide notations for crossed product rings, skew fields of fractions as well as Dubrovin-rings and prove some technical statements which are used in later parts. The second chapter focuses on Hughes-free skew fields of fractions and their connection to Dubrovin-rings. For that purpose we introduce series representations to interpret elements of Hughes-free skew fields of fractions as skew formal Laurent series. This 1 Introduction allows us to prove that for Conradian left-ordered groups G of maximal rank the statement "F[G; η, σ] has a Hughes-free skew field of fractions" implies "The Dubrovin ring of F [G; η, σ] is a skew field". We will also prove the reverse and apply the results to give a new prove of Theorem 1 in [13]. Furthermore we will show how to extend injective ring homomorphisms of some crossed product rings onto their Hughes-free skew fields of fractions. At last we will be able to answer the open question whether Hughes--free skew fields are strongly Hughes-free (cf. [17, page 53]).},
  language  = {en}
}
@phdthesis{Jantzen2019,
  author    = {Jantzen, Friederike},
  title     = {Genetic basis and adaptive significance of repeated scent loss in selfing Capsella species},
  doi       = {10.25932/publishup-43525},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-435253},
  school      = {Universit{\"a}t Potsdam},
  pages     = {124},
  year      = {2019},
  abstract  = {Floral scent is an important way for plants to communicate with insects, but scent emission has been lost or strongly reduced during the transition from pollinator-mediated outbreeding to selfing. The shift from outcrossing to selfing is not only accompanied by scent loss, but also by a reduction in other pollinator-attracting traits like petal size and can be observed multiple times among angiosperms. These changes are summarized by the term selfing syndrome and represent one of the most prominent examples of convergent evolution within the plant kingdom. In this work the genus Capsella was used as a model to study convergent evolution in two closely related selfers with separate transitions to self-fertilization. Compared to their outbreeding ancestor C. grandiflora, the emission of benzaldehyde as main compound of floral scent is lacking or strongly reduced in the selfing species C. rubella and C. orientalis. In C. rubella the loss of benzaldehyde was caused by mutations to cinnamate:CoA ligase CNL1, but the biochemical basis and evolutionary history of this loss remained unknown, together with the genetic basis of scent loss in C. orientalis. Here, a combination of plant transformations, in vitro enzyme assays, population genetics and quantitative genetics has been used to address these questions. The results indicate that CNL1 has been inactivated twice independently by point mutations in C. rubella, leading to a loss of benzaldehyde emission. Both inactivated haplotypes can be found around the Mediterranean Sea, indicating that they arose before the species´ geographical spread. This study confirmed CNL1 as a hotspot for mutations to eliminate benzaldehyde emission, as it has been suggested by previous studies. In contrast to these findings, CNL1 in C. orientalis remains active. To test whether similar mechanisms underlie the convergent evolution of scent loss in C. orientalis a QTL mapping approach was used and the results suggest that this closely related species followed a different evolutionary route to reduce floral scent, possibly reflecting that the convergent evolution of floral scent is driven by ecological rather than genetic factors. In parallel with studying the genetic basis of repeated scent loss a method for testing the adaptive value of individual selfing syndrome traits was established. The established method allows estimating outcrossing rates with a high throughput of samples and detects successfully insect-mediated outcrossing events, providing major advantages regarding time and effort compared to other approaches. It can be applied to correlate outcrossing rates with differences in individual traits by using quasi-isogenic lines as demonstrated here or with environmental or morphological parameters. Convergent evolution can not only be observed for scent loss in Capsella but also for the morphological evolution of petal size. Previous studies detected several QTLs underlying the petal size reduction in C. orientalis and C. rubella, some of them shared among both species. One shared QTL is PAQTL1 which might map to NUBBIN, a growth factor. To better understand the morphological evolution and genetic basis of petal size reduction, this QTL was studied. Mapping this QTL to a gene might identify another example for a hotspot gene, in this case for the convergent evolution of petal size.},
  language  = {en}
}
@phdthesis{Kagel2019,
  author    = {Kagel, Heike},
  title     = {Light-induced pH cycle},
  doi       = {10.25932/publishup-43435},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-434353},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VI, 118},
  year      = {2019},
  abstract  = {Background Many biochemical reactions depend on the pH of their environment and some are strongly accelerated in an acidic surrounding. A classical approach to control biochemical reactions non-invasivly is by changing the temperature. However, if the pH could be controlled by optical means using photo-active chemicals, this would mean to be able to accelerate suitable biochemical reactions. Optically switching the pH can be achieved by using photoacids. A photoacid is a molecule with a functional group that releases a proton upon irradiation with the suitable wavelength, acidifying the environmental aqueous surrounding. A major goal of this work was to establish a non-invasive method of optically controlling the pH in aqueous solutions, offering the opportunity to enhance the known chemical reactions portfolio. To demonstrate the photo-switchable pH cycling we chose an enzymatic assay using acid phosphatase, which is an enzyme with a strong pH dependent activity. Results In this work we could demonstrate a light-induced, reversible control of the enzymatic activity of acid phosphatase non-invasivly. To successfully conduct those experiments a high power LED array was designed and built, suitable for a 96 well standard microtiter plate, not being commercially available. Heat management and a lateral ventilation system to avoid heat accumulation were established and a stable light intensity achieved. Different photoacids were characterised and their pH dependent absorption spectra recorded. By using the reversible photoacid G-acid as a proton donor, the pH can be changed reversibly using high power UV 365 nm LEDs. To demonstrate the pH cycling, acid phosphatase with hydrolytic activity under acidic conditions was chosen. An assay using the photoacid together with the enzyme was established, also providing that G-acid does not inhibit acid phosphatase. The feasibility of reversibly regulating the enzyme's pH dependent activity by optical means was demonstrated, by controlling the enzymatic activity with light. It was demonstrated that the enzyme activity depends on the light exposure time only. When samples are not illuminated and left in the dark, no enzymatic activity was recorded. The process can be rapidly controlled by simply switching the light on and off and should be applicable to a wide range of enzymes and biochemical reactions. Conclusions Reversible photoacids offer a light-dependent regulation of pH, making them extremely attractive for miniaturizable, non-invasive and time-resolved control of biochemical reactions. Many enzymes have a sharp pH dependent activity, thus the established setup in this thesis could be used for a versatile enzyme portfolio. Even though the demonstrated photo-switchable strategy could also be used for non-enzymatic assays, greatly facilitating the assay establishment. Photoacids have the potential for high throughput methods and automation. We demonstrated that it is possible to control photoacids using commonly available LEDs, making their use in highly integrated devices and instruments more attractive. The successfully designed 96 well high power UV LED array presents an opportunity for general combinatorial analysis in e.g. photochemistry, where a high light intensity is needed for the investigation of various reactions.},
  language  = {en}
}
@phdthesis{Kav2019,
  author    = {Kav, Batuhan},
  title     = {Membrane adhesion mediated via lipid-anchored saccharides},
  doi       = {10.25932/publishup-42879},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428790},
  school      = {Universit{\"a}t Potsdam},
  pages     = {125},
  year      = {2019},
  abstract  = {Membrane adhesion is a fundamental biological process in which membranes are attached to neighboring membranes or surfaces. Membrane adhesion emerges from a complex interplay between the binding of membrane-anchored receptors/ligands and the membrane properties. In this work, we study membrane adhesion mediated by lipid-anchored saccharides using microsecond-long full-atomistic molecular dynamics simulations. Motivated by neutron scattering experiments on membrane adhesion via lipid-anchored saccharides, we investigate the role of LeX, Lac1, and Lac2 saccharides and membrane fluctuations in membrane adhesion. We study the binding of saccharides in three different systems: for saccharides in water, for saccharides anchored to essentially planar membranes at fixed separations, and for saccharides anchored to apposing fluctuating membranes. Our simulations of two saccharides in water indicate that the saccharides engage in weak interactions to form dimers. We find that the binding occurs in a continuum of bound states instead of a certain number of well-defined bound structures, which we term as "diffuse binding". The binding of saccharides anchored to essentially planar membranes strongly depends on separation of the membranes, which is fixed in our simulation system. We show that the binding constants for trans-interactions of two lipid-anchored saccharides monotonically decrease with increasing separation. Saccharides anchored to the same membrane leaflet engage in cis-interactions with binding constants comparable to the trans-binding constants at the smallest membrane separations. The interplay of cis- and trans-binding can be investigated in simulation systems with many lipid-anchored saccharides. For Lac2, our simulation results indicate a positive cooperativity of trans- and cis-binding. In this cooperative binding the trans-binding constant is enhanced by the cis-interactions. For LeX, in contrast, we observe no cooperativity between trans- and cis-binding. In addition, we determine the forces generated by trans-binding of lipid-anchored saccharides in planar membranes from the binding-induced deviations of the lipid-anchors. We find that the forces acting on trans-bound saccharides increase with increasing membrane separation to values of the order of 10 pN. The binding of saccharides anchored to the fluctuating membranes results from an interplay between the binding properties of the lipid-anchored saccharides and membrane fluctuations. Our simulations, which have the same average separation of the membranes as obtained from the neutron scattering experiments, yield a binding constant larger than in planar membranes with the same separation. This result demonstrates that membrane fluctuations play an important role at average membrane separations which are seemingly too large for effective binding. We further show that the probability distribution of the local separation can be well approximated by a Gaussian distribution. We calculate the relative membrane roughness and show that our results are in good agreement with the roughness values reported from the neutron scattering experiments.},
  language  = {en}
}