@phdthesis{Yishai2019, author = {Yishai, Oren}, title = {Engineering the reductive glycine pathway in Escherichia coli}, school = {Universit{\"a}t Potsdam}, pages = {86}, year = {2019}, language = {en} } @phdthesis{RuizRodriguez2019, author = {Ruiz Rodriguez, Janete Lorena}, title = {Osmotic pressure effects on collagen mimetic peptides}, school = {Universit{\"a}t Potsdam}, pages = {139}, year = {2019}, abstract = {Collagen is the most abundant protein in mammals. In many tissues, collagen molecules assemble to form a hierarchical structure. In the smallest supramolecular unit, named fibril, each molecule is displaced in the axial direction with respect to its neighbors. This staggering creates a periodic gap and overlap regions, where the gap regions exhibit 20\% less density. These fibril-forming collagens play an essential role in the strength of connective tissues. Despite much effort, directed at understanding collagen function and regulation, the influence of the chemical environment on the local structural and mechanical properties remains poorly understood. Recent studies, aimed at elucidating the effect of osmotic pressure, showed that collagen contracts upon water removal. This observation highlights the importance of water for the stabilization and mechanics of the collagen molecule. Using collagen mimetic peptides (CMPs), which fold into triple helical structures reminiscent of natural collagen, the primary goal of this work was to investigate the effect of the osmotic pressure on specific collagen-mimetic sequences. CMPs were used as the model system as they provide sequence control, which is essential for discriminating local from global structural changes and for relating the observed effects to existing knowledge about the full-length collagen molecule. Of specific interest was the structure of individual collagen triple helices as well as their organization into self-assembled higher order structures. These key structural features were monitored with infrared spectroscopy (IR) and synchrotron X-ray scattering, while varying the osmotic pressure. For controlling the osmotic pressure, CMP powder samples were incubated in air of defined relative humidity, ranging from dry conditions to highly "humid". In addition, to obtain more biologically relevant conditions, the CMPs were measured in ultrapure water and in solutions containing small molecule osmolytes. Using the sequences (Pro-Pro-Gly)10, (Pro-Hyp-Gly)10 and (Hyp-Hyp-Gly)10, it was shown that CMPs with different degrees of proline hydroxylation (Hyp = hydroxyproline) exhibit a sequence-specific response to osmotic pressure. IR spectroscopy revealed that osmotic pressure changes affect the strength of the triple helix stabilizing, interchain hydrogen bond and that the extent of this change depends on the degree of hydroxylation. X-ray scattering experiments further showed that changes in osmotic pressure affect both the molecular length as well as the higher order organization of CMPs. Starting from a pseudo-hexagonal packing in the dry state, all three CMPs showed isotropic swelling when increasing the water content to approximately 1.2 water molecules per amino acid, again to different extents depending on the degree of hydroxylation. When increasing the water content further, this pseudo-hexagonal arrangement breaks down. In the fully hydrated state, each CMP is characterized by its own specific and more complex packing geometry. While these changes in the lateral packing arrangement suggest swelling upon hydration, an overall decrease of the molecular length (i.e. contraction) was observed in the axial direction. Also for this structural feature, a strong dependency on the specific amino acid sequence was found. Interestingly, the observed contraction is the opposite of what has been reported for natural collagen. As (Pro-Pro-Gly)n, (Pro-Hyp-Gly)n and (Hyp-Hyp-Gly)n repeat units are found in collagen with a relatively high abundance, this suggests that other collagen sequence fragments need to respond to hydration in the opposite way to obtain a net elongation of the full-length collagen molecule. To test this hypothesis, sequences predicted to be sensitive to osmotic pressure were considered. One such sequence, consisting of two repeat units (Ala-Arg-Gly-Ser-Asp-Gly), was inserted as a guest into a (Pro-Pro-Gly) host. When compared to the canonical CMP sequences investigated earlier, the lateral helix packing follows a similar trend with increasing hydration; however, the host-guest CMP axially elongates with increasing water content. This behavior is more similar to what has been found for natural collagen and suggests that different sequences do determine the molecular length of collagen sequences differently. Interestingly, the canonical sequences are more abundant in the overlap region while the guest sequence is found in the gap region. This allows to speculate that sequences in the gap and overlap regions possess a specifically fine-tuned local response to osmotic pressure changes. Clearly, more experiments with additional sequences are needed to confirm this. In conclusion, the results obtained in this work indicate a highly sequence specific interaction between collagen and water. Osmotic pressure-induced conformational changes mostly originate from local geometries and bonding patterns and affect both the structure of individual triple helices as well as higher order assemblies. One key remaining question is how these conformational changes affect the local mechanical properties of the collagen molecule. As a first step, the stiffness (persistence length) of full-length collagen was determined using atomic force microscopy. In the future, experimental strategies need to be developed that allow for investigating the mechanical properties of specific collagen sequences, e.g. performing single-molecule force spectroscopy of CMPs.}, language = {en} } @techreport{BruttelFelgendreherGuethetal.2019, type = {Working Paper}, author = {Bruttel, Lisa Verena and Felgendreher, Simon and G{\"u}th, Werner and Hertwig, Ralph}, title = {Strategic ignorance in repeated prisoners' dilemma experiments and its effects on the dynamics of voluntary cooperation}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {10}, issn = {2628-653X}, doi = {10.25932/publishup-43188}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431881}, pages = {30}, year = {2019}, abstract = {Being ignorant of key aspects of a strategic interaction can represent an advantage rather than a handicap. We study one particular context in which ignorance can be beneficial: iterated strategic interactions in which voluntary cooperation may be sustained into the final round if players voluntarily forego knowledge about the time horizon. We experimentally examine this option to remain ignorant about the time horizon in a finitely repeated two-person prisoners' dilemma game. We confirm that pairs without horizon knowledge avoid the drop in cooperation that otherwise occurs toward the end of the game. However, this effect is superposed by cooperation declining more rapidly in pairs without horizon knowledge during the middle phase of the game, especially if players do not know that the other player also wanted to remain ignorant of the time horizon.}, 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} } @article{Šimik2019, author = {Šim{\´i}k, Radek}, title = {On doubling unconditionals}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43226}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432267}, pages = {155 -- 169}, year = {2019}, language = {en} } @article{Mueller2019, author = {M{\"u}ller, Gereon}, title = {Can unaccusative verbs undergo passivization in German?}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43225}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432257}, pages = {135 -- 154}, year = {2019}, language = {en} } @article{Błaszczak2019, author = {Błaszczak, Joanna}, title = {Why is a predicate inversion analysis problematic?}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43224}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432240}, pages = {119 -- 133}, year = {2019}, language = {en} } @article{Alexiadou2019, author = {Alexiadou, Artemis}, title = {A form-function mismatch?}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43223}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432235}, pages = {107 -- 117}, year = {2019}, language = {en} } @article{BacskaiAtkari2019, author = {Bacskai-Atkari, Julia}, title = {Towards a Fanselownian analysis of degree expressions}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43222}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432222}, pages = {95 -- 106}, year = {2019}, language = {en} } @article{Georgi2019, author = {Georgi, Doreen}, title = {Intermediate reflexes of movement}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43221}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432217}, pages = {77 -- 93}, year = {2019}, language = {en} } @article{Cavar2019, author = {Cavar, Damir}, title = {Measuring lexical semantic variation using word embeddings}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43220}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-432201}, pages = {61 -- 74}, year = {2019}, language = {en} } @phdthesis{Tiwari2019, author = {Tiwari, Abhishek}, title = {Enhancing Users' Privacy: Static Resolution of the Dynamic Properties of Android}, school = {Universit{\"a}t Potsdam}, pages = {xiii, 111}, year = {2019}, abstract = {The usage of mobile devices is rapidly growing with Android being the most prevalent mobile operating system. Thanks to the vast variety of mobile applications, users are preferring smartphones over desktops for day to day tasks like Internet surfing. Consequently, smartphones store a plenitude of sensitive data. This data together with the high values of smartphones make them an attractive target for device/data theft (thieves/malicious applications). Unfortunately, state-of-the-art anti-theft solutions do not work if they do not have an active network connection, e.g., if the SIM card was removed from the device. In the majority of these cases, device owners permanently lose their smartphone together with their personal data, which is even worse. Apart from that malevolent applications perform malicious activities to steal sensitive information from smartphones. Recent research considered static program analysis to detect dangerous data leaks. These analyses work well for data leaks due to inter-component communication, but suffer from shortcomings for inter-app communication with respect to precision, soundness, and scalability. This thesis focuses on enhancing users' privacy on Android against physical device loss/theft and (un)intentional data leaks. It presents three novel frameworks: (1) ThiefTrap, an anti-theft framework for Android, (2) IIFA, a modular inter-app intent information flow analysis of Android applications, and (3) PIAnalyzer, a precise approach for PendingIntent vulnerability analysis. ThiefTrap is based on a novel concept of an anti-theft honeypot account that protects the owner's data while preventing a thief from resetting the device. We implemented the proposed scheme and evaluated it through an empirical user study with 35 participants. In this study, the owner's data could be protected, recovered, and anti-theft functionality could be performed unnoticed from the thief in all cases. IIFA proposes a novel approach for Android's inter-component/inter-app communication (ICC/IAC) analysis. Our main contribution is the first fully automatic, sound, and precise ICC/IAC information flow analysis that is scalable for realistic apps due to modularity, avoiding combinatorial explosion: Our approach determines communicating apps using short summaries rather than inlining intent calls between components and apps, which requires simultaneously analyzing all apps installed on a device. We evaluate IIFA in terms of precision, recall, and demonstrate its scalability to a large corpus of real-world apps. IIFA reports 62 problematic ICC-/IAC-related information flows via two or more apps/components. PIAnalyzer proposes a novel approach to analyze PendingIntent related vulnerabilities. PendingIntents are a powerful and universal feature of Android for inter-component communication. We empirically evaluate PIAnalyzer on a set of 1000 randomly selected applications and find 1358 insecure usages of PendingIntents, including 70 severe vulnerabilities.}, language = {en} } @phdthesis{Teckentrup2019, author = {Teckentrup, Lisa}, title = {Understanding predator-prey interactions}, doi = {10.25932/publishup-43162}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431624}, school = {Universit{\"a}t Potsdam}, pages = {ix, 133}, year = {2019}, abstract = {Predators can have numerical and behavioral effects on prey animals. While numerical effects are well explored, the impact of behavioral effects is unclear. Furthermore, behavioral effects are generally either analyzed with a focus on single individuals or with a focus on consequences for other trophic levels. Thereby, the impact of fear on the level of prey communities is overlooked, despite potential consequences for conservation and nature management. In order to improve our understanding of predator-prey interactions, an assessment of the consequences of fear in shaping prey community structures is crucial. In this thesis, I evaluated how fear alters prey space use, community structure and composition, focusing on terrestrial mammals. By integrating landscapes of fear in an existing individual-based and spatially-explicit model, I simulated community assembly of prey animals via individual home range formation. The model comprises multiple hierarchical levels from individual home range behavior to patterns of prey community structure and composition. The mechanistic approach of the model allowed for the identification of underlying mechanism driving prey community responses under fear. My results show that fear modified prey space use and community patterns. Under fear, prey animals shifted their home ranges towards safer areas of the landscape. Furthermore, fear decreased the total biomass and the diversity of the prey community and reinforced shifts in community composition towards smaller animals. These effects could be mediated by an increasing availability of refuges in the landscape. Under landscape changes, such as habitat loss and fragmentation, fear intensified negative effects on prey communities. Prey communities in risky environments were subject to a non-proportional diversity loss of up to 30\% if fear was taken into account. Regarding habitat properties, I found that well-connected, large safe patches can reduce the negative consequences of habitat loss and fragmentation on prey communities. Including variation in risk perception between prey animals had consequences on prey space use. Animals with a high risk perception predominantly used safe areas of the landscape, while animals with a low risk perception preferred areas with a high food availability. On the community level, prey diversity was higher in heterogeneous landscapes of fear if individuals varied in their risk perception compared to scenarios in which all individuals had the same risk perception. Overall, my findings give a first, comprehensive assessment of the role of fear in shaping prey communities. The linkage between individual home range behavior and patterns at the community level allows for a mechanistic understanding of the underlying processes. My results underline the importance of the structure of the landscape of fear as a key driver of prey community responses, especially if the habitat is threatened by landscape changes. Furthermore, I show that individual landscapes of fear can improve our understanding of the consequences of trait variation on community structures. Regarding conservation and nature management, my results support calls for modern conservation approaches that go beyond single species and address the protection of biotic interactions.}, language = {en} } @article{Stiebels2019, author = {Stiebels, Barbara}, title = {Bienenfresserortungsversuch}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43192}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431921}, pages = {15 -- 26}, year = {2019}, language = {en} } @phdthesis{Devkar2019, author = {Devkar, Vikas Suresh}, title = {Functional characterization of NAC transcription factors ATAF1 and SITAF1 in growth and abiotic stress tolerance in tomato}, school = {Universit{\"a}t Potsdam}, year = {2019}, language = {en} } @phdthesis{RomeroMujalli2019, author = {Romero Mujalli, Daniel}, title = {Ecological modeling of adaptive evolutionary responses to rapid climate change}, doi = {10.25932/publishup-43062}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430627}, school = {Universit{\"a}t Potsdam}, pages = {167}, year = {2019}, abstract = {A contemporary challenge in Ecology and Evolutionary Biology is to anticipate the fate of populations of organisms in the context of a changing world. Climate change and landscape changes due to anthropic activities have been of major concern in the contemporary history. Organisms facing these threats are expected to respond by local adaptation (i.e., genetic changes or phenotypic plasticity) or by shifting their distributional range (migration). However, there are limits to their responses. For example, isolated populations will have more difficulties in developing adaptive innovations by means of genetic changes than interconnected metapopulations. Similarly, the topography of the environment can limit dispersal opportunities for crawling organisms as compared to those that rely on wind. Thus, populations of species with different life history strategy may differ in their ability to cope with changing environmental conditions. However, depending on the taxon, empirical studies investigating organisms' responses to environmental change may become too complex, long and expensive; plus, complications arising from dealing with endangered species. In consequence, eco-evolutionary modeling offers an opportunity to overcome these limitations and complement empirical studies, understand the action and limitations of underlying mechanisms, and project into possible future scenarios. In this work I take a modeling approach and investigate the effect and relative importance of evolutionary mechanisms (including phenotypic plasticity) on the ability for local adaptation of populations with different life strategy experiencing climate change scenarios. For this, I performed a review on the state of the art of eco-evolutionary Individual-Based Models (IBMs) and identify gaps for future research. Then, I used the results from the review to develop an eco-evolutionary individual-based modeling tool to study the role of genetic and plastic mechanisms in promoting local adaption of populations of organisms with different life strategies experiencing scenarios of climate change and environmental stochasticity. The environment was simulated through a climate variable (e.g., temperature) defining a phenotypic optimum moving at a given rate of change. The rate of change was changed to simulate different scenarios of climate change (no change, slow, medium, rapid climate change). Several scenarios of stochastic noise color resembling different climatic conditions were explored. Results show that populations of sexual species will rely mainly on standing genetic variation and phenotypic plasticity for local adaptation. Population of species with relatively slow growth rate (e.g., large mammals) - especially those of small size - are the most vulnerable, particularly if their plasticity is limited (i.e., specialist species). In addition, whenever organisms from these populations are capable of adaptive plasticity, they can buffer fitness losses in reddish climatic conditions. Likewise, whenever they can adjust their plastic response (e.g., bed-hedging strategy) they will cope with bluish environmental conditions as well. In contrast, life strategies of high fecundity can rely on non-adaptive plasticity for their local adaptation to novel environmental conditions, unless the rate of change is too rapid. A recommended management measure is to guarantee interconnection of isolated populations into metapopulations, such that the supply of useful genetic variation can be increased, and, at the same time, provide them with movement opportunities to follow their preferred niche, when local adaptation becomes problematic. This is particularly important for bluish and reddish climatic conditions, when the rate of change is slow, or for any climatic condition when the level of stress (rate of change) is relatively high.}, language = {en} } @phdthesis{Yang2019, author = {Yang, Haojin}, title = {Deep representation learning for multimedia data analysis}, school = {Universit{\"a}t Potsdam}, pages = {278}, year = {2019}, language = {en} } @phdthesis{Jehle2019, author = {Jehle, Franziska}, title = {Tracking self-assembly of hierarchically structured soft matter}, school = {Universit{\"a}t Potsdam}, pages = {88}, year = {2019}, language = {en} } @phdthesis{Ehnert2019, author = {Ehnert, Franziska}, title = {Climate Policy in Denmark, Germany, Estonia and Poland}, series = {New horizons in environmental politics}, journal = {New horizons in environmental politics}, publisher = {Edward Elgar Publishing}, address = {Cheltenham, UK and Northampton, MA, USA}, isbn = {978-1-78897-939-9}, school = {Universit{\"a}t Potsdam}, pages = {220}, year = {2019}, abstract = {Ministerial administrations are pivotal in the process of defining problems and developing policy solutions due to their technocratic expertise, particularly when this process is applied to climate policy. This innovative book explores how and why policies are changed or continued by employing in-depth studies from a diverse range of EU countries. Climate Policy in Denmark, Germany, Estonia and Poland works to narrow the research gap surrounding administrative institutions within the field of climate policy change by integrating ideas, discourses and institutions to provide a better understanding of both climate policy and policy change. Differences in approach to democratization and Europeanization between Western and Central Eastern European countries provide rich empirical material for the study of policy formulation. This timely book demonstrates how the substance and formation of policies are shaped by their political and administrative institutional contexts. Analytical and accessible, this discerning book will be of value to scholars and students of climate policy, public policy and public administration alike. Providing lessons on institutional reform in climate and energy policy, this explorative book will also be of interest to practitioners and policy-makers.}, language = {en} } @phdthesis{Yan2019, author = {Yan, Runyu}, title = {Nitrogen-doped and porous carbons towards new energy storage mechanisms for supercapacitors with high energy density}, doi = {10.25932/publishup-43141}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-431413}, school = {Universit{\"a}t Potsdam}, pages = {152}, year = {2019}, abstract = {Supercapacitors are electrochemical energy storage devices with rapid charge/discharge rate and long cycle life. Their biggest challenge is the inferior energy density compared to other electrochemical energy storage devices such as batteries. Being the most widely spread type of supercapacitors, electrochemical double-layer capacitors (EDLCs) store energy by electrosorption of electrolyte ions on the surface of charged electrodes. As a more recent development, Na-ion capacitors (NICs) are expected to be a more promising tactic to tackle the inferior energy density due to their higher-capacity electrodes and larger operating voltage. The charges are simultaneously stored by ion adsorption on the capacitive-type cathode surface and via faradic process in the battery-type anode, respectively. Porous carbon electrodes are of great importance in these devices, but the paramount problems are the facile synthetic routes for high-performance carbons and the lack of fundamental understanding of the energy storage mechanisms. Therefore, the aim of the present dissertation is to develop novel synthetic methods for (nitrogen-doped) porous carbon materials with superior performance, and to reveal a deeper understanding energy storage mechanisms of EDLCs and NICs. The first part introduces a novel synthetic method towards hierarchical ordered meso-microporous carbon electrode materials for EDLCs. The large amount of micropores and highly ordered mesopores endow abundant sites for charge storage and efficient electrolyte transport, respectively, giving rise to superior EDLC performance in different electrolytes. More importantly, the controversial energy storage mechanism of EDLCs employing ionic liquid (IL) electrolytes is investigated by employing a series of porous model carbons as electrodes. The results not only allow to conclude on the relations between the porosity and ion transport dynamics, but also deliver deeper insights into the energy storage mechanism of IL-based EDLCs which is different from the one usually dominating in solvent-based electrolytes leading to compression double-layers. The other part focuses on anodes of NICs, where novel synthesis of nitrogen-rich porous carbon electrodes and their sodium storage mechanism are investigated. Free-standing fibrous nitrogen-doped carbon materials are synthesized by electrospinning using the nitrogen-rich monomer (hexaazatriphenylene-hexacarbonitrile, C18N12) as the precursor followed by condensation at high temperature. These fibers provide superior capacity and desirable charge/discharge rate for sodium storage. This work also allows insights into the sodium storage mechanism in nitrogen-doped carbons. Based on this mechanism, further optimization is done by designing a composite material composed of nitrogen-rich carbon nanoparticles embedded in conductive carbon matrix for a better charge/discharge rate. The energy density of the assembled NICs significantly prevails that of common EDLCs while maintaining the high power density and long cycle life.}, language = {en} } @article{Hennemann2019, author = {Hennemann, Anja}, title = {"I mean, no soy psic{\´o}loga"}, doi = {10.25932/publishup-43098}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430984}, pages = {23}, year = {2019}, abstract = {This paper is concerned with the qualitative analysis of the use of the English discourse marker I mean in Spanish and Portuguese online discourses (in online fora, blogs or user comments on websites). The examples are retrieved from the Corpus del Espa{\~n}ol (Web/ Dialects) as well as the Corpus do Portugu{\^e}s (Web/ Dialects).}, 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} } @misc{HeckKanehiraKneippetal.2019, author = {Heck, Christian and Kanehira, Yuya and Kneipp, Janina and Bald, Ilko}, title = {Amorphous Carbon Generation as a Photocatalytic Reaction on DNA-Assembled Gold and Silver Nanostructures}, series = {Mathematisch-Naturwissenschaftliche Reihe}, journal = {Mathematisch-Naturwissenschaftliche Reihe}, number = {732}, issn = {1866-8372}, doi = {10.25932/publishup-43081}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430812}, pages = {10}, year = {2019}, abstract = {Background signals from in situ-formed amorphous carbon, despite not being fully understood, are known to be a common issue in few-molecule surface-enhanced Raman scattering (SERS). Here, discrete gold and silver nanoparticle aggregates assembled by DNA origami were used to study the conditions for the formation of amorphous carbon during SERS measurements. Gold and silver dimers were exposed to laser light of varied power densities and wavelengths. Amorphous carbon prevalently formed on silver aggregates and at high power densities. Time-resolved measurements enabled us to follow the formation of amorphous carbon. Silver nanolenses consisting of three differently-sized silver nanoparticles were used to follow the generation of amorphous carbon at the single-nanostructure level. This allowed observation of the many sharp peaks that constitute the broad amorphous carbon signal found in ensemble measurements. In conclusion, we highlight strategies to prevent amorphous carbon formation, especially for DNA-assembled SERS substrates.}, language = {en} } @article{HeckKanehiraKneippetal.2019, author = {Heck, Christian and Kanehira, Yuya and Kneipp, Janina and Bald, Ilko}, title = {Amorphous Carbon Generation as a Photocatalytic Reaction on DNA-Assembled Gold and Silver Nanostructures}, series = {Molecules}, volume = {24}, journal = {Molecules}, number = {12}, publisher = {MDPI}, address = {Basel}, issn = {1420-3049}, doi = {10.3390/molecules24122324}, pages = {10}, year = {2019}, abstract = {Background signals from in situ-formed amorphous carbon, despite not being fully understood, are known to be a common issue in few-molecule surface-enhanced Raman scattering (SERS). Here, discrete gold and silver nanoparticle aggregates assembled by DNA origami were used to study the conditions for the formation of amorphous carbon during SERS measurements. Gold and silver dimers were exposed to laser light of varied power densities and wavelengths. Amorphous carbon prevalently formed on silver aggregates and at high power densities. Time-resolved measurements enabled us to follow the formation of amorphous carbon. Silver nanolenses consisting of three differently-sized silver nanoparticles were used to follow the generation of amorphous carbon at the single-nanostructure level. This allowed observation of the many sharp peaks that constitute the broad amorphous carbon signal found in ensemble measurements. In conclusion, we highlight strategies to prevent amorphous carbon formation, especially for DNA-assembled SERS substrates.}, language = {en} } @article{Kleemann2019, author = {Kleemann, Steven}, title = {The Forgotten War: Yemen}, series = {Staat, Recht und Politik - Forschungs- und Diskussionspapiere}, journal = {Staat, Recht und Politik - Forschungs- und Diskussionspapiere}, number = {8}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {2509-6974}, doi = {10.25932/publishup-43071}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430716}, year = {2019}, abstract = {The conflict in Yemen seems forgotten considering the worldwide severe humanitarian catastrophes. Nevertheless, since the conflict escalated around four years ago, it became one of the worst humanitarian crises in recent history and has no end in sight. Thousands of people were killed even more displaced and the country is facing tremendous food insecurity as well as the world's largest cholera outbreak. It is no longer just a civil war between the Houthi- and Hadi-Faction. International interests play a major role and made it a proxy war between Saudi Arabia (and its allies) on one side and Iran on the other. This all happens at the expense of the civilian population. Therefore, it is urgent to analyse the actors involved, their interests within the conflict and furthermore searching for possibilities to overcome it.}, 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} } @article{Olsen2019, author = {Olsen, Susan}, title = {The instrumental -er suffix}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43060}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430607}, pages = {3 -- 14}, year = {2019}, language = {en} } @article{BrownSchmidtWierzba2019, author = {Brown, Jessica M. M. and Schmidt, Andreas and Wierzba, Marta}, title = {Preface}, series = {Of trees and birds. A Festschrift for Gisbert Fanselow}, journal = {Of trees and birds. A Festschrift for Gisbert Fanselow}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-43057}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430575}, pages = {xiii -- xvi}, year = {2019}, language = {en} } @phdthesis{Baleka2019, author = {Baleka, Sina Isabelle}, title = {Palaeogenetic analyses of extinct Elephantidae from temperate and subtropical climates}, school = {Universit{\"a}t Potsdam}, pages = {xiii, 114}, year = {2019}, language = {en} } @misc{AgarwalCaesarMarwanetal.2019, author = {Agarwal, Ankit and Caesar, Levke and Marwan, Norbert and Maheswaran, Rathinasamy and Merz, Bruno}, title = {Network-based identification and characterization of teleconnections on different scales}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {731}, issn = {1866-8372}, doi = {10.25932/publishup-43052}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430520}, pages = {12}, year = {2019}, abstract = {Sea surface temperature (SST) patterns can - as surface climate forcing - affect weather and climate at large distances. One example is El Ni{\~n}o-Southern Oscillation (ENSO) that causes climate anomalies around the globe via teleconnections. Although several studies identified and characterized these teleconnections, our understanding of climate processes remains incomplete, since interactions and feedbacks are typically exhibited at unique or multiple temporal and spatial scales. This study characterizes the interactions between the cells of a global SST data set at different temporal and spatial scales using climate networks. These networks are constructed using wavelet multi-scale correlation that investigate the correlation between the SST time series at a range of scales allowing instantaneously deeper insights into the correlation patterns compared to traditional methods like empirical orthogonal functions or classical correlation analysis. This allows us to identify and visualise regions of - at a certain timescale - similarly evolving SSTs and distinguish them from those with long-range teleconnections to other ocean regions. Our findings re-confirm accepted knowledge about known highly linked SST patterns like ENSO and the Pacific Decadal Oscillation, but also suggest new insights into the characteristics and origins of long-range teleconnections like the connection between ENSO and Indian Ocean Dipole.}, language = {en} } @article{AgarwalCaesarMarwanetal.2019, author = {Agarwal, Ankit and Caesar, Levke and Marwan, Norbert and Maheswaran, Rathinasamy and Merz, Bruno}, title = {Network-based identification and characterization of teleconnections on different scales}, series = {Scientific Reports}, volume = {9}, journal = {Scientific Reports}, publisher = {Macmillan Publishers Limited}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-019-45423-5}, pages = {12}, year = {2019}, abstract = {Sea surface temperature (SST) patterns can - as surface climate forcing - affect weather and climate at large distances. One example is El Ni{\~n}o-Southern Oscillation (ENSO) that causes climate anomalies around the globe via teleconnections. Although several studies identified and characterized these teleconnections, our understanding of climate processes remains incomplete, since interactions and feedbacks are typically exhibited at unique or multiple temporal and spatial scales. This study characterizes the interactions between the cells of a global SST data set at different temporal and spatial scales using climate networks. These networks are constructed using wavelet multi-scale correlation that investigate the correlation between the SST time series at a range of scales allowing instantaneously deeper insights into the correlation patterns compared to traditional methods like empirical orthogonal functions or classical correlation analysis. This allows us to identify and visualise regions of - at a certain timescale - similarly evolving SSTs and distinguish them from those with long-range teleconnections to other ocean regions. Our findings re-confirm accepted knowledge about known highly linked SST patterns like ENSO and the Pacific Decadal Oscillation, but also suggest new insights into the characteristics and origins of long-range teleconnections like the connection between ENSO and Indian Ocean Dipole.}, language = {en} } @phdthesis{Haase2019, author = {Haase, Nadin}, title = {The nascent peptide chain in the ribosomal exit tunnel}, school = {Universit{\"a}t Potsdam}, pages = {105}, year = {2019}, language = {en} } @phdthesis{Jiang2019, author = {Jiang, Yi}, title = {Tailoring surface functions of micro/nanostructured polymeric substrates by thermo-mechanical treatments}, school = {Universit{\"a}t Potsdam}, pages = {93}, year = {2019}, language = {en} } @phdthesis{Liu2019, author = {Liu, Jiabo}, title = {Dynamics of the geomagnetic field during the last glacial}, doi = {10.25932/publishup-42946}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429461}, school = {Universit{\"a}t Potsdam}, pages = {xv, 158}, year = {2019}, abstract = {Geomagnetic paleosecular variations (PSVs) are an expression of geodynamo processes inside the Earth's liquid outer core. These paleomagnetic time series provide insights into the properties of the Earth's magnetic field, from normal behavior with a dominating dipolar geometry, over field crises, such as pronounced intensity lows and geomagnetic excursions with a distorted field geometry, to the complete reversal of the dominating dipole contribution. Particularly, long-term high-resolution and high-quality PSV time series are needed for properly reconstructing the higher frequency components in the spectrum of geomagnetic field variations and for a better understanding of the effects of smoothing during the recording of such paleomagnetic records by sedimentary archives. In this doctorate study, full vector paleomagnetic records were derived from 16 sediment cores recovered from the southeastern Black Sea. Age models are based on radiocarbon dating and correlations of warming/cooling cycles monitored by high-resolution X-ray fluorescence (XRF) elementary ratios as well as ice-rafted debris (IRD) in Black Sea sediments to the sequence of 'Dansgaard-Oeschger' (DO) events defined from Greenland ice core oxygen isotope stratigraphy. In order to identify the carriers of magnetization in Black Sea sediments, core MSM33-55-1 recovered from the southeast Black Sea was subjected to detailed rock magnetic and electron microscopy investigations. The younger part of core MSM33-55-1 was continuously deposited since 41 ka. Before 17.5 ka, the magnetic minerals were dominated by a mixture of greigite (Fe3S4) and titanomagnetite (Fe3-xTixO4) in samples with SIRM/κLF >10 kAm-1, or exclusively by titanomagnetite in samples with SIRM/κLF ≤10 kAm-1. It was found that greigite is generally present as crustal aggregates in locally reducing micro-environments. From 17.5 ka to 8.3 ka, the dominant magnetic mineral in this transition phase was changing from greigite (17.5 - ~10.0 ka) to probably silicate-hosted titanomagnetite (~10.0 - 8.3 ka). After 8.3 ka, the anoxic Black Sea was a favorable environment for the formation of non-magnetic pyrite (FeS2) framboids. Aiming to avoid compromising of paleomagnetic data by erroneous directions carried by greigite, paleomagnetic data from samples with SIRM/κLF >10 kAm-1, shown to contain greigite by various methods, were removed from obtained records. Consequently, full vector paleomagnetic records, comprising directional data and relative paleointensity (rPI), were derived only from samples with SIRM/κLF ≤10 kAm-1 from 16 Black Sea sediment cores. The obtained data sets were used to create a stack covering the time window between 68.9 and 14.5 ka with temporal resolution between 40 and 100 years, depending on sedimentation rates. At 64.5 ka, according to obtained results from Black Sea sediments, the second deepest minimum in relative paleointensity during the past 69 ka occurred. The field minimum during MIS 4 is associated with large declination swings beginning about 3 ka before the minimum. While a swing to 50°E is associated with steep inclinations (50-60°) according to the coring site at 42°N, the subsequent declination swing to 30°W is associated with shallow inclinations of down to 40°. Nevertheless, these large deviations from the direction of a geocentric axial dipole field (I=61°, D=0°) still can not yet be termed as 'excursional', since latitudes of corresponding VGPs only reach down to 51.5°N (120°E) and 61.5°N (75°W), respectively. However, these VGP positions at opposite sides of the globe are linked with VGP drift rates of up to 0.2° per year in between. These extreme secular variations might be the mid-latitude expression of the Norwegian-Greenland Sea excursion found at several sites much further North in Arctic marine sediments between 69°N and 81°N. At about 34.5 ka, the Mono Lake excursion is evidenced in the stacked Black Sea PSV record by both a rPI minimum and directional shifts. Associated VGPs from stacked Black Sea data migrated from Alaska, via central Asia and the Tibetan Plateau, to Greenland, performing a clockwise loop. This agrees with data recorded in the Wilson Creek Formation, USA., and Arctic sediment core PS2644-5 from the Iceland Sea, suggesting a dominant dipole field. On the other hand, the Auckland lava flows, New Zealand, the Summer Lake, USA., and Arctic sediment core from ODP Site-919 yield distinct VGPs located in the central Pacific Ocean due to a presumably non-dipole (multi-pole) field configuration. A directional anomaly at 18.5 ka, associated with pronounced swings in inclination and declination, as well as a low in rPI, is probably contemporaneous with the Hilina Pali excursion, originally reported from Hawaiian lava flows. However, virtual geomagnetic poles (VGPs) calculated from Black Sea sediments are not located at latitudes lower than 60° N, which denotes normal, though pronounced secular variations. During the postulated Hilina Pali excursion, the VGPs calculated from Black Sea data migrated clockwise only along the coasts of the Arctic Ocean from NE Canada (20.0 ka), via Alaska (18.6 ka) and NE Siberia (18.0 ka) to Svalbard (17.0 ka), then looping clockwise through the Eastern Arctic Ocean. In addition to the Mono Lake and the Norwegian-Greenland Sea excursions, the Laschamp excursion was evidenced in the Black Sea PSV record with the lowest paleointensities at about 41.6 ka and a short-term (~500 years) full reversal centered at 41 ka. These excursions are further evidenced by an abnormal PSV index, though only the Laschamp and the Mono Lake excursions exhibit excursional VGP positions. The stacked Black Sea paleomagnetic record was also converted into one component parallel to the direction expected from a geocentric axial dipole (GAD) and two components perpendicular to it, representing only non-GAD components of the geomagnetic field. The Laschamp and the Norwegian-Greenland Sea excursions are characterized by extremely low GAD components, while the Mono Lake excursion is marked by large non-GAD contributions. Notably, negative values of the GAD component, indicating a fully reversed geomagnetic field, are observed only during the Laschamp excursion. In summary, this doctoral thesis reconstructed high-resolution and high-fidelity PSV records from SE Black Sea sediments. The obtained record comprises three geomagnetic excursions, the Norwegian-Greenland Sea excursion, the Laschamp excursion, and the Mono Lake excursion. They are characterized by abnormal secular variations of different amplitudes centered at about 64.5 ka, 41.0 ka and 34.5 ka, respectively. In addition, the obtained PSV record from the Black Sea do not provide evidence for the postulated 'Hilina Pali excursion' at about 18.5 ka. Anyway, the obtained Black Sea paleomagnetic record, covering field fluctuations from normal secular variations, over excursions, to a short but full reversal, points to a geomagnetic field characterized by a large dynamic range in intensity and a highly variable superposition of dipole and non-dipole contributions from the geodynamo during the past 68.9 to 14.5 ka.}, language = {en} } @book{OlsenStiebelsBierwischetal.2019, author = {Olsen, Susan and Stiebels, Barbara and Bierwisch, Manfred and Zimmermann, Ilse and Cavar, Damir and Georgi, Doreen and Bacskai-Atkari, Julia and Alexiadou, Artemis and Błaszczak, Joanna and M{\"u}ller, Gereon and Šim{\´i}k, Radek and Meinunger, Andr{\´e} and Thiersch, Craig and Arnhold, Anja and F{\´e}ry, Caroline and Bayer, Josef and Titov, Elena and Fominyam, Henry and Tran, Thuan and Bornkessel-Schlesewsky, Ina D. and Schlesewsky, Matthias and Zimmermann, Malte and H{\"a}ussler, Jana and Mucha, Anne and Schmidt, Andreas and Weskott, Thomas and Wierzba, Marta and Stede, Manfred and Skopeteas, Stavros and Gafos, Adamantios I. and Haider, Hubert and Wunderlich, Dieter and Staudacher, Peter and Rauh, Gisa}, title = {Of Trees and Birds}, editor = {Brown, Jessica M. M. and Schmidt, Andreas and Wierzba, Marta}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-457-9}, doi = {10.25932/publishup-42654}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426542}, publisher = {Universit{\"a}t Potsdam}, pages = {xvi, 435}, year = {2019}, abstract = {Gisbert Fanselow's work has been invaluable and inspiring to many ­researchers working on syntax, morphology, and information ­structure, both from a ­theoretical and from an experimental perspective. This ­volume comprises a collection of articles dedicated to Gisbert on the occasion of his 60th birthday, covering a range of topics from these areas and beyond. The contributions have in ­common that in a broad sense they have to do with language structures (and thus trees), and that in a more specific sense they have to do with birds. They thus cover two of Gisbert's major interests in- and outside of the linguistic world (and ­perhaps even at the interface).}, 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} } @book{OPUS4-43002, title = {Service Design and Service Thinking in Healthcare and Hospital Management}, editor = {Pfannstiel, Mario Alexander and Rasche, Christoph}, publisher = {Springer International Publishing}, address = {Cham}, isbn = {978-3-030-00748-5}, doi = {10.1007/978-3-030-00749-2}, publisher = {Universit{\"a}t Potsdam}, pages = {XVII, 535}, year = {2019}, language = {en} } @misc{SmithRheinwaltBookhagen2019, author = {Smith, Taylor and Rheinwalt, Aljoscha and Bookhagen, Bodo}, title = {Determining the optimal grid resolution for topographic analysis on an airborne lidar dataset}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {725}, issn = {1866-8372}, doi = {10.25932/publishup-43016}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430165}, pages = {475 -- 489}, year = {2019}, abstract = {Digital elevation models (DEMs) are a gridded representation of the surface of the Earth and typically contain uncertainties due to data collection and processing. Slope and aspect estimates on a DEM contain errors and uncertainties inherited from the representation of a continuous surface as a grid (referred to as truncation error; TE) and from any DEM uncertainty. We analyze in detail the impacts of TE and propagated elevation uncertainty (PEU) on slope and aspect. Using synthetic data as a control, we define functions to quantify both TE and PEU for arbitrary grids. We then develop a quality metric which captures the combined impact of both TE and PEU on the calculation of topographic metrics. Our quality metric allows us to examine the spatial patterns of error and uncertainty in topographic metrics and to compare calculations on DEMs of different sizes and accuracies. Using lidar data with point density of ∼10 pts m-2 covering Santa Cruz Island in southern California, we are able to generate DEMs and uncertainty estimates at several grid resolutions. Slope (aspect) errors on the 1 m dataset are on average 0.3∘ (0.9∘) from TE and 5.5∘ (14.5∘) from PEU. We calculate an optimal DEM resolution for our SCI lidar dataset of 4 m that minimizes the error bounds on topographic metric calculations due to the combined influence of TE and PEU for both slope and aspect calculations over the entire SCI. Average slope (aspect) errors from the 4 m DEM are 0.25∘ (0.75∘) from TE and 5∘ (12.5∘) from PEU. While the smallest grid resolution possible from the high-density SCI lidar is not necessarily optimal for calculating topographic metrics, high point-density data are essential for measuring DEM uncertainty across a range of resolutions.}, language = {en} } @article{SmithRheinwaltBookhagen2019, author = {Smith, Taylor and Rheinwalt, Aljoscha and Bookhagen, Bodo}, title = {Determining the optimal grid resolution for topographic analysis on an airborne lidar dataset}, series = {Earth Surface Dynamics}, volume = {7}, journal = {Earth Surface Dynamics}, publisher = {Copernicus Publ.}, address = {G{\"o}ttingen}, issn = {2196-6311}, doi = {10.5194/esurf-7-475-2019}, pages = {475 -- 489}, year = {2019}, abstract = {Digital elevation models (DEMs) are a gridded representation of the surface of the Earth and typically contain uncertainties due to data collection and processing. Slope and aspect estimates on a DEM contain errors and uncertainties inherited from the representation of a continuous surface as a grid (referred to as truncation error; TE) and from any DEM uncertainty. We analyze in detail the impacts of TE and propagated elevation uncertainty (PEU) on slope and aspect. Using synthetic data as a control, we define functions to quantify both TE and PEU for arbitrary grids. We then develop a quality metric which captures the combined impact of both TE and PEU on the calculation of topographic metrics. Our quality metric allows us to examine the spatial patterns of error and uncertainty in topographic metrics and to compare calculations on DEMs of different sizes and accuracies. Using lidar data with point density of ∼10 pts m-2 covering Santa Cruz Island in southern California, we are able to generate DEMs and uncertainty estimates at several grid resolutions. Slope (aspect) errors on the 1 m dataset are on average 0.3∘ (0.9∘) from TE and 5.5∘ (14.5∘) from PEU. We calculate an optimal DEM resolution for our SCI lidar dataset of 4 m that minimizes the error bounds on topographic metric calculations due to the combined influence of TE and PEU for both slope and aspect calculations over the entire SCI. Average slope (aspect) errors from the 4 m DEM are 0.25∘ (0.75∘) from TE and 5∘ (12.5∘) from PEU. While the smallest grid resolution possible from the high-density SCI lidar is not necessarily optimal for calculating topographic metrics, high point-density data are essential for measuring DEM uncertainty across a range of resolutions.}, language = {en} } @techreport{SultanowKochCox2019, author = {Sultanow, Eldar and Koch, Christian and Cox, Sean}, title = {Collatz Sequences in the Light of Graph Theory}, doi = {10.25932/publishup-43008}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-430089}, pages = {15}, year = {2019}, abstract = {The Collatz conjecture is a number theoretical problem, which has puzzled countless researchers using myriad approaches. Presently, there are scarcely any methodologies to describe and treat the problem from the perspective of the Algebraic Theory of Automata. Such an approach is promising with respect to facilitating the comprehension of the Collatz sequences "mechanics". The systematic technique of a state machine is both simpler and can fully be described by the use of algebraic means. The current gap in research forms the motivation behind the present contribution. The present authors are convinced that exploring the Collatz conjecture in an algebraic manner, relying on findings and fundamentals of Graph Theory and Automata Theory, will simplify the problem as a whole.}, language = {en} } @phdthesis{Nikkhoo2019, author = {Nikkhoo, Mehdi}, title = {Analytical and numerical elastic dislocation models of volcano deformation processes}, doi = {10.25932/publishup-42972}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429720}, school = {Universit{\"a}t Potsdam}, pages = {x, 175}, year = {2019}, abstract = {The advances in modern geodetic techniques such as the global navigation satellite system (GNSS) and synthetic aperture radar (SAR) provide surface deformation measurements with an unprecedented accuracy and temporal and spatial resolutions even at most remote volcanoes on Earth. Modelling of the high-quality geodetic data is crucial for understanding the underlying physics of volcano deformation processes. Among various approaches, mathematical models are the most effective for establishing a quantitative link between the surface displacements and the shape and strength of deformation sources. Advancing the geodetic data analyses and hence, the knowledge on the Earth's interior processes, demands sophisticated and efficient deformation modelling approaches. Yet the majority of these models rely on simplistic assumptions for deformation source geometries and ignore complexities such as the Earth's surface topography and interactions between multiple sources. This thesis addresses this problem in the context of analytical and numerical volcano deformation modelling. In the first part, new analytical solutions for triangular dislocations (TDs) in uniform infinite and semi-infinite elastic media have been developed. Through a comprehensive investigation, the locations and causes of artefact singularities and numerical instabilities associated with TDs have been determined and these long-standing drawbacks have been addressed thoroughly. This approach has then been extended to rectangular dislocations (RDs) with full rotational degrees of freedom. Using this solution in a configuration of three orthogonal RDs a compound dislocation model (CDM) has been developed. The CDM can represent generalized volumetric and planar deformation sources efficiently. Thus, the CDM is relevant for rapid inversions in early warning systems and can also be used for detailed deformation analyses. In order to account for complex source geometries and realistic topography in the deformation models, in this thesis the boundary element method (BEM) has been applied to the new solutions for TDs. In this scheme, complex surfaces are simulated as a continuous mesh of TDs that may possess any displacement or stress boundary conditions in the BEM calculations. In the second part of this thesis, the developed modelling techniques have been applied to five different real-world deformation scenarios. As the first and second case studies the deformation sources associated with the 2015 Calbuco eruption and 2013-2016 Copahue inflation period have been constrained by using the CDM. The highly anisotropic source geometries in these two cases highlight the importance of using generalized deformation models such as the CDM, for geodetic data inversions. The other three case studies in this thesis involve high-resolution dislocation models and BEM calculations. As the third case, the 2013 pre-explosive inflation of Volc{\´a}n de Colima has been simulated by using two ellipsoidal cavities, which locate zones of pressurization in the volcano's lava dome. The fourth case study, which serves as an example for volcanotectonics interactions, the 3-D kinematics of an active ring-fault at Tend{\"u}rek volcano has been investigated through modelling displacement time series over the 2003-2010 time period. As the fifth example, the deformation sources associated with North Korea's underground nuclear test in September 2017 have been constrained. These examples demonstrate the advancement and increasing level of complexity and the general applicability of the developed dislocation modelling techniques. This thesis establishes a unified framework for rapid and high-resolution dislocation modelling, which in addition to volcano deformations can also be applied to tectonic and humanmade deformations.}, 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{Riedel2019, author = {Riedel, Simona}, title = {Characterization of Mitochondrial ABC Transporter Homologues in Rhodobacter capsulatus}, school = {Universit{\"a}t Potsdam}, pages = {127}, year = {2019}, abstract = {ABC-Transporter (ABC abgeleitet von ATP-Binding Cassette) geh{\"o}ren zur Klasse der Transmembran-Proteine und kommen in allen drei Dom{\"a}nen des Lebens vor. Ihr struktureller Aufbau ist dabei stets {\"a}hnlich, wohingegen konservierte Proteinsequenzen selten vorkommen. Die Transporter sind aus zwei lipophilen, membran-durchspannenden Dom{\"a}nen, welche auch TMDs (abgeleitet von Transmembrane spanning Domains) genannt werden, und zwei hydrophilen Dom{\"a}nen, die auch NBDs (abgeleitet von Nucleotide Binding Domains) genannt werden, aufgebaut. Die Vielzahl der durch ABC-Transporter bef{\"o}rderten Molek{\"u}le erkl{\"a}rt dabei die enorme Anzahl diverser TMDs. In den Mitochondrien des Menschen findet man vier ABC-Transporter (ABCB6, ABCB7, ABCB8 und ABCB10) mit funktionellen Homologen in Hefen und Pflanzen. In Bakterien hingegen k{\"o}nnen, mit Ausnahme von Rickettsiae und verwandten Bakterien, keine Homologen zu mitochondrialen ABC-Transportern identifiziert werden. Die transportierten Molek{\"u}le sowie die damit verbundenen Funktionen sind im Einzelnen bislang weitgehend unbekannt. ABCB7 und die entsprechenden Homologen in Hefen (Atm1) und in Pflanzen (ATM3) konnten mit der cytosolischen Eisen-Schwefel-Cluster-Biosynthese in Zusammenhang gebracht werden. Eine schwefelhaltige Verbindung der mitochondrialen Matrix wird mit Hilfe dieses Transporters der cytosolischen Eisen-Schwefel-Cluster-Assemblierung zur Verf{\"u}gung gestellt. Die 2014 publizierten Kristallstrukturen von Atm1 (Hefe) und Atm1 aus Novosphingobium aromaticivorans offenbarten dabei eine hoch konservierte Glutathion-Bindetasche innerhalb der TMDs f{\"u}r ABCB7 Homologe. In der Modellpflanze Arabidopsis thaliana konnte ATM3 zus{\"a}tzlich mit der Biosynthese des Molybd{\"a}n-Cofaktors in Verbindung gebracht werden. In der vorliegenden Arbeit wurde das α-Proteobacterium Rhodobacter capsulatus als Modellorganismus genutzt, um mitochondriale ABC-Transporter Homologe zu untersuchen. Das Bakterium enth{\"a}lt zwei ABC-Transporter-Gene, rcc03139 und rcc02305, die mit den humanen mitochondrialen Transportern große Sequenz{\"u}bereinstimmungen aufweisen (rcc03139: 41 \% respektive 38 \% Identit{\"a}t mit ABCB8 und ABCB10, rcc02305: 47 \% identisch mit ABCB7 und ABCB6). Mit Hilfe erzeugter Interposon-Mutanten (Δrcc02305I und Δrcc03139I) konnte erstmals gezeigt werden, dass bakterielle Transporter funktionell sehr {\"a}hnliche Aufgaben wie die mitochondrialen ABC-Transporter {\"u}bernehmen. Beispielsweise akkumulierten beide Interposon-Mutanten reaktive Sauerstoff-Spezies (ROS) ohne gleichzeitige Akkumulation von Glutathion oder Eisen. Weiterhin konnten wir zeigen, dass, {\"a}hnlich wie bereits f{\"u}r ATM3 postuliert, die Biosynthese des Molybd{\"a}n-Cofaktors in Δrcc02305I ver{\"a}ndert ist. Mit Hilfe einer lebensf{\"a}higen Doppelmutante, in der beide ABC-Transporter-Gene gleichzeitig deletiert wurden, konnten wir ausschließen, dass die beiden bakteriellen ABC-Transporter grunds{\"a}tzlich redundante Funktionen haben. Durch die Analyse des Proteoms von Δrcc03139I im Vergleich zu der des Wildtyps, konnte eine extreme Beeinflussung der Tetrapyrrol Biosynthese sowie entsprechender Zielproteine identifiziert werden. Dies konnte zus{\"a}tzlich durch die Quantifizierung einzelner Zwischenprodukte der Biosynthese best{\"a}tigt werden. Im Gegensatz dazu konnte anhand der Analyse des Proteoms in Verbindung mit analytischen Methoden in Δrcc02305I ein Ungleichgewicht in der Schwefelverteilung identifiziert werden. Zusammen mit der Entdeckung einer Pyridoxalphosphat (PLP) Bindestelle in Rcc02305 und anderen ABCB7-artigen Transportern, welche direkt mit dem Walker-A-Motiv der NBD {\"u}berlappt, erm{\"o}glichte dies eine v{\"o}llig neue Theorie, wie die schwefelhaltige Verbindung transportiert werden kann. Wir gehen davon aus, dass an PLP zun{\"a}chst ein Persulfid produziert wird, welches unmittelbar mit dem Glutathion der transmembranen Bindetasche zu einem gemischten Polysulfid reagiert. Im Anschluss daran wird die ATP-Bindestelle frei und die Hydrolyse des ATPs l{\"o}st eine Konformations{\"a}nderung aus, welche das gemischte Polysulfid ins Periplasma bzw. in den intermembranen Raum freigibt.}, language = {en} } @phdthesis{LopezGarcia2019, author = {L{\´o}pez Garc{\´i}a, Patricia}, title = {Coiled coils as mechanical building blocks}, doi = {10.25932/publishup-42956}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429568}, school = {Universit{\"a}t Potsdam}, pages = {xi, 130}, year = {2019}, abstract = {The natural abundance of Coiled Coil (CC) motifs in cytoskeleton and extracellular matrix proteins suggests that CCs play an important role as passive (structural) and active (regulatory) mechanical building blocks. CCs are self-assembled superhelical structures consisting of 2-7 α-helices. Self-assembly is driven by hydrophobic and ionic interactions, while the helix propensity of the individual helices contributes additional stability to the structure. As a direct result of this simple sequence-structure relationship, CCs serve as templates for protein design and sequences with a pre-defined thermodynamic stability have been synthesized de novo. Despite this quickly increasing knowledge and the vast number of possible CC applications, the mechanical function of CCs has been largely overlooked and little is known about how different CC design parameters determine the mechanical stability of CCs. Once available, this knowledge will open up new applications for CCs as nanomechanical building blocks, e.g. in biomaterials and nanobiotechnology. With the goal of shedding light on the sequence-structure-mechanics relationship of CCs, a well-characterized heterodimeric CC was utilized as a model system. The sequence of this model system was systematically modified to investigate how different design parameters affect the CC response when the force is applied to opposing termini in a shear geometry or separated in a zipper-like fashion from the same termini (unzip geometry). The force was applied using an atomic force microscope set-up and dynamic single-molecule force spectroscopy was performed to determine the rupture forces and energy landscape properties of the CC heterodimers under study. Using force as a denaturant, CC chain separation is initiated by helix uncoiling from the force application points. In the shear geometry, this allows uncoiling-assisted sliding parallel to the force vector or dissociation perpendicular to the force vector. Both competing processes involve the opening of stabilizing hydrophobic (and ionic) interactions. Also in the unzip geometry, helix uncoiling precedes the rupture of hydrophobic contacts. In a first series of experiments, the focus was placed on canonical modifications in the hydrophobic core and the helix propensity. Using the shear geometry, it was shown that both a reduced core packing and helix propensity lower the thermodynamic and mechanical stability of the CC; however, with different effects on the energy landscape of the system. A less tightly packed hydrophobic core increases the distance to the transition state, with only a small effect on the barrier height. This originates from a more dynamic and less tightly packed core, which provides more degrees of freedom to respond to the applied force in the direction of the force vector. In contrast, a reduced helix propensity decreases both the distance to the transition state and the barrier height. The helices are 'easier' to unfold and the remaining structure is less thermodynamically stable so that dissociation perpendicular to the force axis can occur at smaller deformations. Having elucidated how canonical sequence modifications influence CC mechanics, the pulling geometry was investigated in the next step. Using one and the same sequence, the force application points were exchanged and two different shear and one unzipping geometry were compared. It was shown that the pulling geometry determines the mechanical stability of the CC. Different rupture forces were observed in the different shear as well as in the unzipping geometries, suggesting that chain separation follows different pathways on the energy landscape. Whereas the difference between CC shearing and unzipping was anticipated and has also been observed for other biological structures, the observed difference for the two shear geometries was less expected. It can be explained with the structural asymmetry of the CC heterodimer. It is proposed that the direction of the α-helices, the different local helix propensities and the position of a polar asparagine in the hydrophobic core are responsible for the observed difference in the chain separation pathways. In combination, these factors are considered to influence the interplay between processes parallel and perpendicular to the force axis. To obtain more detailed insights into the role of helix stability, helical turns were reinforced locally using artificial constraints in the form of covalent and dynamic 'staples'. A covalent staple bridges to adjacent helical turns, thus protecting them against uncoiling. The staple was inserted directly at the point of force application in one helix or in the same terminus of the other helix, which did not experience the force directly. It was shown that preventing helix uncoiling at the point of force application reduces the distance to the transition state while slightly increasing the barrier height. This confirms that helix uncoiling is critically important for CC chain separation. When inserted into the second helix, this stabilizing effect is transferred across the hydrophobic core and protects the force-loaded turns against uncoiling. If both helices were stapled, no additional increase in mechanical stability was observed. When replacing the covalent staple with a dynamic metal-coordination bond, a smaller decrease in the distance to the transition was observed, suggesting that the staple opens up while the CC is under load. Using fluorinated amino acids as another type of non-natural modification, it was investigated how the enhanced hydrophobicity and the altered packing at the interface influences CC mechanics. The fluorinated amino acid was inserted into one central heptad of one or both α-helices. It was shown that this substitution destabilized the CC thermodynamically and mechanically. Specifically, the barrier height was decreased and the distance to the transition state increased. This suggests that a possible stabilizing effect of the increased hydrophobicity is overruled by a disturbed packing, which originates from a bad fit of the fluorinated amino acid into the local environment. This in turn increases the flexibility at the interface, as also observed for the hydrophobic core substitution described above. In combination, this confirms that the arrangement of the hydrophobic side chains is an additional crucial factor determining the mechanical stability of CCs. In conclusion, this work shows that knowledge of the thermodynamic stability alone is not sufficient to predict the mechanical stability of CCs. It is the interplay between helix propensity and hydrophobic core packing that defines the sequence-structure-mechanics relationship. In combination, both parameters determine the relative contribution of processes parallel and perpendicular to the force axis, i.e. helix uncoiling and uncoiling-assisted sliding as well as dissociation. This new mechanistic knowledge provides insight into the mechanical function of CCs in tissues and opens up the road for designing CCs with pre-defined mechanical properties. The library of mechanically characterized CCs developed in this work is a powerful starting point for a wide spectrum of applications, ranging from molecular force sensors to mechanosensitive crosslinks in protein nanostructures and synthetic extracellular matrix mimics.}, language = {en} } @misc{UnuabonahNoeskeWeberetal.2019, author = {Unuabonah, Emmanuel Iyayi and N{\"o}ske, Robert and Weber, Jens and G{\"u}nter, Christina and Taubert, Andreas}, title = {New micro/mesoporous nanocomposite material from low-cost sources for the efficient removal of aromatic and pathogenic pollutants from water}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {720}, doi = {10.25932/publishup-42621}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426214}, pages = {119 -- 131}, year = {2019}, abstract = {A new micro/mesoporous hybrid clay nanocomposite prepared from kaolinite clay, Carica papaya seeds, and ZnCl2 via calcination in an inert atmosphere is presented. Regardless of the synthesis temperature, the specific surface area of the nanocomposite material is between ≈150 and 300 m2/g. The material contains both micro- and mesopores in roughly equal amounts. X-ray diffraction, infrared spectroscopy, and solid-state nuclear magnetic resonance spectroscopy suggest the formation of several new bonds in the materials upon reaction of the precursors, thus confirming the formation of a new hybrid material. Thermogravimetric analysis/differential thermal analysis and elemental analysis confirm the presence of carbonaceous matter. The new composite is stable up to 900 °C and is an efficient adsorbent for the removal of a water micropollutant, 4-nitrophenol, and a pathogen, E. coli, from an aqueous medium, suggesting applications in water remediation are feasible.}, language = {en} } @phdthesis{Peter2019, author = {Peter, Franziska}, title = {Transition to synchrony in finite Kuramoto ensembles}, doi = {10.25932/publishup-42916}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429168}, school = {Universit{\"a}t Potsdam}, pages = {vi, 93}, year = {2019}, abstract = {Synchronisation - die Ann{\"a}herung der Rhythmen gekoppelter selbst oszillierender Systeme - ist ein faszinierendes dynamisches Ph{\"a}nomen, das in vielen biologischen, sozialen und technischen Systemen auftritt. Die vorliegende Arbeit befasst sich mit Synchronisation in endlichen Ensembles schwach gekoppelter selbst-erhaltender Oszillatoren mit unterschiedlichen nat{\"u}rlichen Frequenzen. Das Standardmodell f{\"u}r dieses kollektive Ph{\"a}nomen ist das Kuramoto-Modell - unter anderem aufgrund seiner L{\"o}sbarkeit im thermodynamischen Limes unendlich vieler Oszillatoren. {\"A}hnlich einem thermodynamischen Phasen{\"u}bergang zeigt im Fall unendlich vieler Oszillatoren ein Ordnungsparameter den {\"U}bergang von Inkoh{\"a}renz zu einem partiell synchronen Zustand an, in dem ein Teil der Oszillatoren mit einer gemeinsamen Frequenz rotiert. Im endlichen Fall treten Fluktuationen auf. In dieser Arbeit betrachten wir den bisher wenig beachteten Fall von bis zu wenigen hundert Oszillatoren, unter denen vergleichbar starke Fluktuationen auftreten, bei denen aber ein Vergleich zu Frequenzverteilungen im unendlichen Fall m{\"o}glich ist. Zun{\"a}chst definieren wir einen alternativen Ordnungsparameter zur Feststellung einer kollektiven Mode im endlichen Kuramoto-Modell. Dann pr{\"u}fen wir die Abh{\"a}ngigkeit des Synchronisationsgrades und der mittleren Rotationsfrequenz der kollektiven Mode von Eigenschaften der nat{\"u}rlichen Frequenzverteilung f{\"u}r verschiedene Kopplungsst{\"a}rken. Wir stellen dabei zun{\"a}chst numerisch fest, dass der Synchronisationsgrad stark von der Form der Verteilung (gemessen durch die Kurtosis) und die Rotationsfrequenz der kollektiven Mode stark von der Asymmetrie der Verteilung (gemessen durch die Schiefe) der nat{\"u}rlichen Frequenzen abh{\"a}ngt. Beides k{\"o}nnen wir im thermodynamischen Limes analytisch verifizieren. Mit diesen Ergebnissen k{\"o}nnen wir Erkenntnisse anderer Autoren besser verstehen und verallgemeinern. Etwas abseits des roten Fadens dieser Arbeit finden wir außerdem einen analytischen Ausdruck f{\"u}r die Volumenkontraktion im Phasenraum. Der zweite Teil der Arbeit konzentriert sich auf den ordnenden Effekt von Fluktuationen, die durch die Endlichkeit des Systems zustande kommen. Im unendlichen Modell sind die Oszillatoren eindeutig in koh{\"a}rent und inkoh{\"a}rent und damit in geordnet und ungeordnet getrennt. Im endlichen Fall k{\"o}nnen die auftretenden Fluktuationen zus{\"a}tzliche Ordnung unter den asynchronen Oszillatoren erzeugen. Das grundlegende Prinzip, die rauschinduzierte Synchronisation, ist aus einer Reihe von Publikationen bekannt. Unter den gekoppelten Oszillatoren n{\"a}hern sich die Phasen aufgrund der Fluktuationen des Ordnungsparameters an, wie wir einerseits direkt numerisch zeigen und andererseits mit einem Synchronisationsmaß aus der gerichteten Statistik zwischen Paaren passiver Oszillatoren nachweisen. Wir bestimmen die Abh{\"a}ngigkeit dieses Synchronisationsmaßes vom Verh{\"a}ltnis von paarweiser nat{\"u}rlicher Frequenzdifferenz zur Varianz der Fluktuationen. Dabei finden wir eine gute {\"U}bereinstimmung mit einem einfachen analytischen Modell, in welchem wir die deterministischen Fluktuationen des Ordnungsparameters durch weißes Rauschen ersetzen.}, language = {en} } @phdthesis{Kurpiers2019, author = {Kurpiers, Jona}, title = {Probing the pathways of free charge generation and recombination in organic solar cells}, doi = {10.25932/publishup-42909}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429099}, school = {Universit{\"a}t Potsdam}, pages = {VI, 128, xxi}, year = {2019}, abstract = {Organic semiconductors are a promising class of materials. Their special properties are the particularly good absorption, low weight and easy processing into thin films. Therefore, intense research has been devoted to the realization of thin film organic solar cells (OPVs). Because of the low dielectric constant of organic semiconductors, primary excitations (excitons) are strongly bound and a type II heterojunction needs to be introduced to split these excitations into free charges. Therefore, most organic solar cells consist of at least an electron donor and electron acceptor material. For such donor acceptor systems mainly three states are relevant; the photoexcited exciton on the donor or acceptor material, the charge transfer state at the donor-acceptor interface and the charge separated state of a free electron and hole. The interplay between these states significantly determines the efficiency of organic solar cells. Due to the high absorption and the low charge carrier mobilities, the active layers are usually thin but also, exciton dissociation and free charge formation proceeds rapidely, which makes the study of carrier dynamics highly challenging. Therefore, the focus of this work was first to install new experimental setups for the investigation of the charge carrier dynamics in complete devices with superior sensitivity and time resolution and, second, to apply these methods to prototypical photovoltaic materials to address specific questions in the field of organic and hybrid photovoltaics. Regarding the first goal, a new setup combining transient absorption spectroscopy (TAS) and time delayed collection field (TDCF) was designed and installed in Potsdam. An important part of this work concerned the improvement of the electronic components with respect to time resolution and sensitivity. To this end, a highly sensitive amplifier for driving and detecting the device response in TDCF was developed. This system was then applied to selected organic and hybrid model systems with a particular focus on the understanding of the loss mechanisms that limit the fill factor and short circuit current of organic solar cells. The first model system was a hybrid photovoltaic material comprising inorganic quantum dots decorated with organic ligands. Measurements with TDCF revealed fast free carrier recombination, in part assisted by traps, while bias-assisted charge extraction measurements showed high mobility. The measured parameters then served as input for a successful description of the device performance with an analytical model. With a further improvement of the instrumentation, a second topic was the detailed analysis of non-geminate recombination in a disordered polymer:fullerene blend where an important question was the effect of disorder on the carrier dynamics. The measurements revealed that early time highly mobile charges undergo fast non-geminate recombination at the contacts, causing an apparent field dependence of free charge generation in TDCF experiments if not conducted properly. On the other hand, recombination the later time scale was determined by dispersive recombination in the bulk of the active layer, showing the characteristics of carrier dynamics in an exponential density of state distribution. Importantly, the comparison with steady state recombination data suggested a very weak impact of non-thermalized carriers on the recombination properties of the solar cells under application relevant illumination conditions. Finally, temperature and field dependent studies of free charge generation were performed on three donor-acceptor combinations, with two donor polymers of the same material family blended with two different fullerene acceptor molecules. These particular material combinations were chosen to analyze the influence of the energetic and morphology of the blend on the efficiency of charge generation. To this end, activation energies for photocurrent generation were accurately determined for a wide range of excitation energies. The results prove that the formation of free charge is via thermalized charge transfer states and does not involve hot exciton splitting. Surprisingly, activation energies were of the order of thermal energy at room temperature. This led to the important conclusion that organic solar cells perform well not because of predominate high energy pathways but because the thermalized CT states are weakly bound. In addition, a model is introduced to interconnect the dissociation efficiency of the charge transfer state with its recombination observable with photoluminescence, which rules out a previously proposed two-pool model for free charge formation and recombination. Finally, based on the results, proposals for the further development of organic solar cells are formulated.}, language = {en} } @phdthesis{Sterzel2019, author = {Sterzel, Till}, title = {Analyzing global typologies of socio-ecological vulnerability}, doi = {10.25932/publishup-42883}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428837}, school = {Universit{\"a}t Potsdam}, pages = {137}, year = {2019}, abstract = {On a planetary scale human populations need to adapt to both socio-economic and environmental problems amidst rapid global change. This holds true for coupled human-environment (socio-ecological) systems in rural and urban settings alike. Two examples are drylands and urban coasts. Such socio-ecological systems have a global distribution. Therefore, advancing the knowledge base for identifying socio-ecological adaptation needs with local vulnerability assessments alone is infeasible: The systems cover vast areas, while funding, time, and human resources for local assessments are limited. They are lacking in low an middle-income countries (LICs and MICs) in particular. But places in a specific socio-ecological system are not only unique and complex - they also exhibit similarities. A global patchwork of local rural drylands vulnerability assessments of human populations to socio-ecological and environmental problems has already been reduced to a limited number of problem structures, which typically cause vulnerability. However, the question arises whether this is also possible in urban socio-ecological systems. The question also arises whether these typologies provide added value in research beyond global change. Finally, the methodology employed for drylands needs refining and standardizing to increase its uptake in the scientific community. In this dissertation, I set out to fill these three gaps in research. The geographical focus in my dissertation is on LICs and MICs, which generally have lower capacities to adapt, and greater adaptation needs, regarding rapid global change. Using a spatially explicit indicator-based methodology, I combine geospatial and clustering methods to identify typical configurations of key factors in case studies causing vulnerability to human populations in two specific socio-ecological systems. Then I use statistical and analytical methods to interpret and appraise both the typical configurations and the global typologies they constitute. First, I improve the indicator-based methodology and then reanalyze typical global problem structures of socio-ecological drylands vulnerability with seven indicator datasets. The reanalysis confirms the key tenets and produces a more realistic and nuanced typology of eight spatially explicit problem structures, or vulnerability profiles: Two new profiles with typically high natural resource endowment emerge, in which overpopulation has led to medium or high soil erosion. Second, I determine whether the new drylands typology and its socio-ecological vulnerability concept advance a thematically linked scientific debate in human security studies: what drives violent conflict in drylands? The typology is a much better predictor for conflict distribution and incidence in drylands than regression models typically used in peace research. Third, I analyze global problem structures typically causing vulnerability in an urban socio-ecological system - the rapidly urbanizing coastal fringe (RUCF) - with eleven indicator datasets. The RUCF also shows a robust typology, and its seven profiles show huge asymmetries in vulnerability and adaptive capacity. The fastest population increase, lowest income, most ineffective governments, most prevalent poverty, and lowest adaptive capacity are all typically stacked in two profiles in LICs. This shows that beyond local case studies tropical cyclones and/or coastal flooding are neither stalling rapid population growth, nor urban expansion, in the RUCF. I propose entry points for scaling up successful vulnerability reduction strategies in coastal cities within the same vulnerability profile. This dissertation shows that patchworks of local vulnerability assessments can be generalized to structure global socio-ecological vulnerabilities in both rural and urban socio-ecological systems according to typical problems. In terms of climate-related extreme events in the RUCF, conflicting problem structures and means to deal with them are threatening to widen the development gap between LICs and high-income countries unless successful vulnerability reduction measures are comprehensively scaled up. The explanatory power for human security in drylands warrants further applications of the methodology beyond global environmental change research in the future. Thus, analyzing spatially explicit global typologies of socio-ecological vulnerability is a useful complement to local assessments: The typologies provide entry points for where to consider which generic measures to reduce typical problem structures - including the countless places without local assessments. This can save limited time and financial resources for adaptation under rapid global change.}, 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} } @misc{AyzelHeistermannWinterrath2019, author = {Ayzel, Georgy and Heistermann, Maik and Winterrath, Tanja}, title = {Optical flow models as an open benchmark for radar-based precipitation nowcasting (rainymotion v0.1)}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {709}, issn = {1866-8372}, doi = {10.25932/publishup-42933}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429333}, pages = {16}, year = {2019}, abstract = {Quantitative precipitation nowcasting (QPN) has become an essential technique in various application contexts, such as early warning or urban sewage control. A common heuristic prediction approach is to track the motion of precipitation features from a sequence of weather radar images and then to displace the precipitation field to the imminent future (minutes to hours) based on that motion, assuming that the intensity of the features remains constant ("Lagrangian persistence"). In that context, "optical flow" has become one of the most popular tracking techniques. Yet the present landscape of computational QPN models still struggles with producing open software implementations. Focusing on this gap, we have developed and extensively benchmarked a stack of models based on different optical flow algorithms for the tracking step and a set of parsimonious extrapolation procedures based on image warping and advection. We demonstrate that these models provide skillful predictions comparable with or even superior to state-of-the-art operational software. Our software library ("rainymotion") for precipitation nowcasting is written in the Python programming language and openly available at GitHub (https://github.com/hydrogo/rainymotion, Ayzel et al., 2019). That way, the library may serve as a tool for providing fast, free, and transparent solutions that could serve as a benchmark for further model development and hypothesis testing - a benchmark that is far more advanced than the conventional benchmark of Eulerian persistence commonly used in QPN verification experiments.}, language = {en} } @article{AyzelHeistermannWinterrath2019, author = {Ayzel, Georgy and Heistermann, Maik and Winterrath, Tanja}, title = {Optical flow models as an open benchmark for radar-based precipitation nowcasting (rainymotion v0.1)}, series = {Geoscientific model development}, journal = {Geoscientific model development}, number = {12}, publisher = {Copernicus Publications}, address = {G{\"o}ttingen}, issn = {1991-9603}, doi = {10.5194/gmd-12-1387-2019}, pages = {1387 -- 1402}, year = {2019}, abstract = {Quantitative precipitation nowcasting (QPN) has become an essential technique in various application contexts, such as early warning or urban sewage control. A common heuristic prediction approach is to track the motion of precipitation features from a sequence of weather radar images and then to displace the precipitation field to the imminent future (minutes to hours) based on that motion, assuming that the intensity of the features remains constant ("Lagrangian persistence"). In that context, "optical flow" has become one of the most popular tracking techniques. Yet the present landscape of computational QPN models still struggles with producing open software implementations. Focusing on this gap, we have developed and extensively benchmarked a stack of models based on different optical flow algorithms for the tracking step and a set of parsimonious extrapolation procedures based on image warping and advection. We demonstrate that these models provide skillful predictions comparable with or even superior to state-of-the-art operational software. Our software library ("rainymotion") for precipitation nowcasting is written in the Python programming language and openly available at GitHub (https://github.com/hydrogo/rainymotion, Ayzel et al., 2019). That way, the library may serve as a tool for providing fast, free, and transparent solutions that could serve as a benchmark for further model development and hypothesis testing - a benchmark that is far more advanced than the conventional benchmark of Eulerian persistence commonly used in QPN verification experiments.}, language = {en} } @phdthesis{Reeg2019, author = {Reeg, Jette}, title = {Simulating the impact of herbicide drift exposure on non-target terrestrial plant communities}, doi = {10.25932/publishup-42907}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429073}, school = {Universit{\"a}t Potsdam}, pages = {178}, year = {2019}, abstract = {In Europe, almost half of the terrestrial landscape is used for agriculture. Thus, semi-natural habitats such as field margins are substantial for maintaining diversity in intensively managed farmlands. However, plants located at field margins are threatened by agricultural practices such as the application of pesticides within the fields. Pesticides are chemicals developed to control for undesired species within agricultural fields to enhance yields. The use of pesticides implies, however, effects on non-target organisms within and outside of the agricultural fields. Non-target organisms are organisms not intended to be sprayed or controlled for. For example, plants occurring in field margins are not intended to be sprayed, however, can be impaired due to herbicide drift exposure. The authorization of plant protection products such as herbicides requires risk assessments to ensure that the application of the product has no unacceptable effects on the environment. For non-target terrestrial plants (NTTPs), the risk assessment is based on standardized greenhouse studies on plant individual level. To account for the protection of plant populations and communities under realistic field conditions, i.e. extrapolating from greenhouse studies to field conditions and from individual-level to community-level, assessment factors are applied. However, recent studies question the current risk assessment scheme to meet the specific protection goals for non-target terrestrial plants as suggested by the European Food Safety Authority (EFSA). There is a need to clarify the gaps of the current risk assessment and to include suitable higher tier options in the upcoming guidance document for non-target terrestrial plants. In my thesis, I studied the impact of herbicide drift exposure on NTTP communities using a mechanistic modelling approach. I addressed main gaps and uncertainties of the current risk assessment and finally suggested this modelling approach as a novel higher tier option in future risk assessments. Specifically, I extended the plant community model IBC-grass (Individual-based community model for grasslands) to reflect herbicide impacts on plant individuals. In the first study, I compared model predictions of short-term herbicide impacts on artificial plant communities with empirical data. I demonstrated the capability of the model to realistically reflect herbicide impacts. In the second study, I addressed the research question whether or not reproductive endpoints need to be included in future risk assessments to protect plant populations and communities. I compared the consequences of theoretical herbicide impacts on different plant attributes for long-term plant population dynamics in the community context. I concluded that reproductive endpoints only need to be considered if the herbicide effect is assumed to be very high. The endpoints measured in the current vegetative vigour and seedling emergence studies had high impacts for the dynamic of plant populations and communities already at lower effect intensities. Finally, the third study analysed long-term impacts of herbicide application for three different plant communities. This study highlighted the suitability of the modelling approach to simulate different communities and thus detecting sensitive environmental conditions. Overall, my thesis demonstrates the suitability of mechanistic modelling approaches to be used as higher tier options for risk assessments. Specifically, IBC-grass can incorporate available individual-level effect data of standardized greenhouse experiments to extrapolate to community-level under various environmental conditions. Thus, future risk assessments can be improved by detecting sensitive scenarios and including worst-case impacts on non-target plant communities.}, language = {en} } @misc{SiegShinkoVogeletal.2019, author = {Sieg, Tobias and Shinko, Thomas and Vogel, Kristin and Mechler, Reinhard and Merz, Bruno and Kreibich, Heidi}, title = {Integrated assessment of short-term direct and indirect economic flood impacts including uncertainty quantification}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {708}, doi = {10.25932/publishup-42911}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429119}, pages = {21}, year = {2019}, abstract = {Understanding and quantifying total economic impacts of flood events is essential for flood risk management and adaptation planning. Yet, detailed estimations of joint direct and indirect flood-induced economic impacts are rare. In this study an innovative modeling procedure for the joint assessment of short-term direct and indirect economic flood impacts is introduced. The procedure is applied to 19 economic sectors in eight federal states of Germany after the flood events in 2013. The assessment of the direct economic impacts is object-based and considers uncertainties associated with the hazard, the exposed objects and their vulnerability. The direct economic impacts are then coupled to a supply-side Input-Output-Model to estimate the indirect economic impacts. The procedure provides distributions of direct and indirect economic impacts which capture the associated uncertainties. The distributions of the direct economic impacts in the federal states are plausible when compared to reported values. The ratio between indirect and direct economic impacts shows that the sectors Manufacturing, Financial and Insurance activities suffered the most from indirect economic impacts. These ratios also indicate that indirect economic impacts can be almost as high as direct economic impacts. They differ strongly between the economic sectors indicating that the application of a single factor as a proxy for the indirect impacts of all economic sectors is not appropriate.}, language = {en} } @article{SiegSchinkoVogeletal.2019, author = {Sieg, Tobias and Schinko, Thomas and Vogel, Kristin and Mechler, Reinhard and Merz, Bruno and Kreibich, Heidi}, title = {Integrated assessment of short-term direct and indirect economic flood impacts including uncertainty quantification}, series = {PLoS ONE}, volume = {14}, journal = {PLoS ONE}, number = {4}, publisher = {Public Library of Science}, address = {San Francisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0212932}, pages = {21}, year = {2019}, abstract = {Understanding and quantifying total economic impacts of flood events is essential for flood risk management and adaptation planning. Yet, detailed estimations of joint direct and indirect flood-induced economic impacts are rare. In this study an innovative modeling procedure for the joint assessment of short-term direct and indirect economic flood impacts is introduced. The procedure is applied to 19 economic sectors in eight federal states of Germany after the flood events in 2013. The assessment of the direct economic impacts is object-based and considers uncertainties associated with the hazard, the exposed objects and their vulnerability. The direct economic impacts are then coupled to a supply-side Input-Output-Model to estimate the indirect economic impacts. The procedure provides distributions of direct and indirect economic impacts which capture the associated uncertainties. The distributions of the direct economic impacts in the federal states are plausible when compared to reported values. The ratio between indirect and direct economic impacts shows that the sectors Manufacturing, Financial and Insurance activities suffered the most from indirect economic impacts. These ratios also indicate that indirect economic impacts can be almost as high as direct economic impacts. They differ strongly between the economic sectors indicating that the application of a single factor as a proxy for the indirect impacts of all economic sectors is not appropriate.}, language = {en} } @techreport{McLachlan2019, type = {Working Paper}, author = {McLachlan, Campbell}, title = {The Double-facing Foreign Relations Function of the Executive and Its Self-enforcing Obligation to Comply with International Law}, series = {KFG Working Paper Series}, journal = {KFG Working Paper Series}, number = {30}, doi = {10.25932/publishup-42908}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-429088}, pages = {35}, year = {2019}, abstract = {How does the international Rule of Law apply to constrain the conduct of the Executive within a constitutional State that adopts a dualist approach to the reception of international law? This paper argues that, so far from being inconsistent with the concept of the Rule of Law, the Executive within a dualist constitution has a self-enforcing obligation to abide by the obligations of the State under international law. This is not dependent on Parliament's incorporation of treaty obligations into domestic law. It is the correlative consequence of the allocation to the Executive of the power to conduct foreign relations. The paper develops this argument in response to recent debate in the United Kingdom on whether Ministers have an obligation to comply with international law-a reference that the Government removed from the Ministerial Code. It shows that such an obligation is consistent with both four centuries of the practice of the British State and with principle.}, 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} } @phdthesis{Schleicher2019, author = {Schleicher, Anja Maria}, title = {The significance of clay minerals in active fault zones}, school = {Universit{\"a}t Potsdam}, pages = {167}, year = {2019}, abstract = {Die vorliegende Habilitationsschrift umfasst Forschungsergebnisse aus Studien, die sich mit Fluid-Gesteins-Wechselwirkungen und Deformationsprozessen in aktiven St{\"o}rungszonen befassen, wobei der Einfluss der Tonminerale auf das geochemische und hydromechanische Verhalten dieser St{\"o}rungen im Vordergrund steht. Kernproben (core) und Bohrklein (cuttings) aus vier verschiedenen Bohrprojekten an der San Andreas St{\"o}rung (USA), der Nankai Trough Subduktionszone und der Japan Trench Subduktionszone (Japan), sowie der Alpine St{\"o}rung in Neuseeland wurden untersucht. Die von ICDP (International Continental Scientific Drilling Program) und IODP (International Ocean Discovery Program) unterst{\"u}tzten Projekte verfolgen alle das Ziel, das Verhalten von Erdbeben besser zu verstehen. In Kapitel 1 werden in einer kurzen Einleitung die allgemeinen thematischen Grundlagen und Ziele der Arbeit beschrieben. Kapitel 2 umfasst den Stand der Forschung, eine kurze Beschreibung der einzelnen Bohrprojekte und Standorte, sowie eine Zusammenfassung der wichtigsten Messmethoden. Kapitel 3 beinhaltet insgesamt zehn wissenschaftliche Arbeiten, die alle in einem methodisch-thematischen Zusammenhang stehen. Die Manuskripte wurden in den Jahren 2006-2015 ver{\"o}ffentlicht, wobei weitere Arbeiten aus diesem Themenbereich im Literaturverzeichnis vermerkt sind. Sie gehen auf unterschiedliche Fragestellungen um die Bildung und das Verhalten von Tonmineralen in aktiven St{\"o}rungszonen ein. Insgesamt sechs Publikationen beinhalten Daten und Forschungsergebnisse, die im Rahmen des SAFOD Projektes, USA (San Andreas Fault Observatory at Depth) erstellt wurden. Hier wurde vor allem auf die Fluid-Gesteins-Wechselwirkungsprozesse im St{\"o}rungsgestein und die daraus resultierende Bildung von Tonmineralen eingegangen. Drei weitere Arbeiten wurden im Rahmen des NanTroSEIZE Projektes, Japan (Nankai Trough Seismogenic Zone Experiment) und des JFAST Projektes, Japan (Japan Trench Fast Drilling Project) erstellt. Hier steht vor allem das Verhalten von quellf{\"a}higen Tonmineralen auf sich {\"a}ndernde Umgebungsbedingungen (z.B. Temperatur und Feuchtigkeit) im Mittelpunkt. Die zehnte hier vorgestellte Ver{\"o}ffentlichung betrifft Analysen rund um das DFDP Projekt (Deep Fault Drilling Project) in Neuseeland, wobei hier die Deformation von Tonmineralen und das hydro-mechanische Verhalten der St{\"o}rungszone im Vordergrund stehen. In neun Ver{\"o}ffentlichungen war ich als Erstautor f{\"u}r die Vorbereitung des Projektes, das Erstellen der Daten und die Fertigstellung der Manuskripte zust{\"a}ndig. In einer Publikation war ich als Mitautorin f{\"u}r die elektronenmikroskopischen Analysen und deren Interpretation verantwortlich. Die wichtigsten Ergebnisse der in Kapitel 3 vorgelegten Arbeiten werden in Kapitel 4 unter Ber{\"u}cksichtigung neuer Publikationen diskutiert. Nach der Beschreibung der Thesen in Kapitel 5 werden in Kapitel 6 „Outlook" die Highlights zuk{\"u}nftiger Forschungspl{\"a}ne am GFZ n{\"a}her beschrieben. Die Habilitationsschrift endet mit dem Anhang, in welchem unter anderem das Laborequipment genauer beschrieben wird, sowie die Publikationen, Konferenzbeitr{\"a}ge und Lehrbeitr{\"a}ge aufgelistet sind.}, language = {en} } @phdthesis{Moffitt2019, author = {Moffitt, Ursula Elinor}, title = {On being and belonging}, series = {Othering, islamophobia, and identity in contemporary Germany}, journal = {Othering, islamophobia, and identity in contemporary Germany}, school = {Universit{\"a}t Potsdam}, pages = {149}, year = {2019}, language = {en} } @phdthesis{Tinpun2019, author = {Tinpun, Kittisak}, title = {Relative rank of infinite full transformation semigroups with restricted range}, school = {Universit{\"a}t Potsdam}, year = {2019}, language = {en} } @techreport{MuellerWrohlich2019, type = {Working Paper}, author = {M{\"u}ller, Kai-Uwe and Wrohlich, Katharina}, title = {Does subsidized care for toddlers increase maternal labor supply?}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {9}, issn = {2628-653X}, doi = {10.25932/publishup-42772}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427727}, pages = {50}, year = {2019}, abstract = {Expanding public or publicly subsidized childcare has been a top social policy priority in many industrialized countries. It is supposed to increase fertility, promote children's development and enhance mothers' labor market attachment. In this paper, we analyze the causal effect of one of the largest expansions of subsidized childcare for children up to three years among industrialized countries on the employment of mothers in Germany. Identification is based on spatial and temporal variation in the expansion of publicly subsidized childcare triggered by two comprehensive childcare policy reforms. The empirical analysis is based on the German Microcensus that is matched to county level data on childcare availability. Based on our preferred specification which includes time and county fixed effects we find that an increase in childcare slots by one percentage point increases mothers' labor market participation rate by 0.2 percentage points. The overall increase in employment is explained by the rise in part-time employment with relatively long hours (20-35 hours per week). We do not find a change in full-time employment or lower part-time employment that is causally related to the childcare expansion. The effect is almost entirely driven by mothers with medium-level qualifications. Mothers with low education levels do not profit from this reform calling for a stronger policy focus on particularly disadvantaged groups in coming years.}, 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} } @techreport{BorckSchrauth2019, type = {Working Paper}, author = {Borck, Rainald and Schrauth, Philipp}, title = {Population density and urban air quality}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {8}, issn = {2628-653X}, doi = {10.25932/publishup-42771}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427719}, pages = {53}, year = {2019}, abstract = {We use panel data from Germany to analyze the effect of population density on urban air pollution (nitrogen oxides, particulate matter and ozone). To address unobserved heterogeneity and omitted variables, we present long difference/fixed effects estimates and instrumental variables estimates, using historical population and soil quality as instruments. Our preferred estimates imply that a one-standard deviation increase in population density increases air pollution by 3-12\%.}, language = {en} } @techreport{BruttelNithammerStolley2019, type = {Working Paper}, author = {Bruttel, Lisa Verena and Nithammer, Juri and Stolley, Florian}, title = {"Thanks in Advance"}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {7}, issn = {2628-653X}, doi = {10.25932/publishup-42770}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427706}, pages = {18}, year = {2019}, abstract = {This paper studies the effect of the commonly used phrase "thanks in advance" on compliance with a small request. In a controlled laboratory experiment we ask participants to give a detailed answer to an open question. The treatment variable is whether or not they see the phrase "thanks in advance." Our participants react to the treatment by exerting less effort in answering the request even though they perceive the phrase as polite.}, language = {en} } @techreport{CaliendoTuebbicke2019, type = {Working Paper}, author = {Caliendo, Marco and T{\"u}bbicke, Stefan}, title = {New Evidence on Long-Term Effects of Start-Up Subsidies}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {6}, issn = {2628-653X}, doi = {10.25932/publishup-42679}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426798}, pages = {41}, year = {2019}, abstract = {The German start-up subsidy (SUS) program for the unemployed has recently undergone a major make-over, altering its institutional setup, adding an additional layer of selection and leading to ambiguous predictions of the program's effectiveness. Using propensity score matching (PSM) as our main empirical approach, we provide estimates of long-term effects of the post-reform subsidy on individual employment prospects and labor market earnings up to 40 months after entering the program. Our results suggest large and persistent long-term effects of the subsidy on employment probabilities and net earned income. These effects are larger than what was estimated for the pre-reform program. Extensive sensitivity analyses within the standard PSM framework reveal that the results are robust to different choices regarding the implementation of the weighting procedure and also with respect to deviations from the conditional independence assumption. As a further assessment of the results' sensitivity, we go beyond the standard selection-on-observables approach and employ an instrumental variable setup using regional variation in the likelihood of receiving treatment. Here, we exploit the fact that the reform increased the discretionary power of local employment agencies in allocating active labor market policy funds, allowing us to obtain a measure of local preferences for SUS as the program of choice. The results based on this approach give rise to similar estimates. Thus, our results indicating that SUS are still an effective active labor market program after the reform do not appear to be driven by "hidden bias".}, language = {en} } @misc{ZeuschnerParpiievPezeriletal.2019, author = {Zeuschner, Steffen Peer and Parpiiev, Tymur and Pezeril, Thomas and Hillion, Arnaud and Dumesnil, Karine and Anane, Abdelmadjid and Pudell, Jan-Etienne and Willig, Lisa and R{\"o}ssle, Matthias and Herzog, Marc and Reppert, Alexander von and Bargheer, Matias}, title = {Tracking picosecond strain pulses in heterostructures that exhibit giant magnetostriction}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-naturwissenschaftliche Reihe}, number = {706}, issn = {1866-8372}, doi = {10.25932/publishup-42845}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428457}, pages = {9}, year = {2019}, abstract = {We combine ultrafast X-ray diffraction (UXRD) and time-resolved Magneto-Optical Kerr Effect (MOKE) measurements to monitor the strain pulses in laser-excited TbFe2/Nb heterostructures. Spatial separation of the Nb detection layer from the laser excitation region allows for a background-free characterization of the laser-generated strain pulses. We clearly observe symmetric bipolar strain pulses if the excited TbFe2 surface terminates the sample and a decomposition of the strain wavepacket into an asymmetric bipolar and a unipolar pulse, if a SiO2 glass capping layer covers the excited TbFe2 layer. The inverse magnetostriction of the temporally separated unipolar strain pulses in this sample leads to a MOKE signal that linearly depends on the strain pulse amplitude measured through UXRD. Linear chain model simulations accurately predict the timing and shape of UXRD and MOKE signals that are caused by the strain reflections from multiple interfaces in the heterostructure.}, language = {en} } @article{ZeuschnerParpiievPezeriletal.2019, author = {Zeuschner, Steffen Peer and Parpiiev, Tymur and Pezeril, Thomas and Hillion, Arnaud and Dumesnil, Karine and Anane, Abdelmadjid and Pudell, Jan-Etienne and Willig, Lisa and R{\"o}ssle, Matthias and Herzog, Marc and Reppert, Alexander von and Bargheer, Matias}, title = {Tracking picosecond strain pulses in heterostructures that exhibit giant magnetostriction}, series = {Structural Dynamics}, volume = {6}, journal = {Structural Dynamics}, number = {2}, publisher = {AIP Publishing LLC}, address = {Melville, NY}, issn = {2329-7778}, doi = {10.1063/1.5084140}, pages = {9}, year = {2019}, abstract = {We combine ultrafast X-ray diffraction (UXRD) and time-resolved Magneto-Optical Kerr Effect (MOKE) measurements to monitor the strain pulses in laser-excited TbFe2/Nb heterostructures. Spatial separation of the Nb detection layer from the laser excitation region allows for a background-free characterization of the laser-generated strain pulses. We clearly observe symmetric bipolar strain pulses if the excited TbFe2 surface terminates the sample and a decomposition of the strain wavepacket into an asymmetric bipolar and a unipolar pulse, if a SiO2 glass capping layer covers the excited TbFe2 layer. The inverse magnetostriction of the temporally separated unipolar strain pulses in this sample leads to a MOKE signal that linearly depends on the strain pulse amplitude measured through UXRD. Linear chain model simulations accurately predict the timing and shape of UXRD and MOKE signals that are caused by the strain reflections from multiple interfaces in the heterostructure.}, language = {en} } @techreport{Bruttel2019, type = {Working Paper}, author = {Bruttel, Lisa Verena}, title = {Is There a Loyalty-Enhancing Effect of Retroactive Price-Reduction Schemes?}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {5}, issn = {2628-653X}, doi = {10.25932/publishup-42768}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427688}, pages = {25}, year = {2019}, abstract = {This paper presents an experiment on the effect of retroactive price-reduction schemes on buyers' repeated purchase decisions. Such schemes promise buyers a reduced price for all units that are bought in a certain time frame if the total quantity that is purchased passes a given threshold. This study finds a loyalty-enhancing effect of retroactive price-reduction schemes only if the buyers ex-ante expected that entering into the scheme would maximize their monetary gain, but later learn that they should leave the scheme. Furthermore, the effect crucially hinges on the framing of the price reduction.}, language = {en} } @techreport{AudretschHafensteinKritikosetal.2019, type = {Working Paper}, author = {Audretsch, David B. and Hafenstein, Marian and Kritikos, Alexander and Schiersch, Alexander}, title = {Firm Size and Innovation in the Service Sector}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {4}, issn = {2628-653X}, doi = {10.25932/publishup-42767}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427670}, pages = {46}, year = {2019}, abstract = {A rich literature links knowledge inputs with innovative outputs. However, most of what is known is restricted to manufacturing. This paper analyzes whether the three aspects involving innovative activity - R\&D; innovative output; and productivity - hold for knowledge intensive services. Combining the models of Crepon et al. (1998) and of Ackerberg et al. (2015), allows for causal interpretation of the relationship between innovation output and labor productivity. We find that knowledge intensive services benefit from innovation activities in the sense that these activities causally increase their labor productivity. Moreover, the firm size advantage found for manufacturing in previous studies nearly disappears for knowledge intensive services.}, language = {en} } @techreport{MuellerNeumannWrohlich2019, type = {Working Paper}, author = {M{\"u}ller, Kai-Uwe and Neumann, Michael and Wrohlich, Katharina}, title = {Labor supply under participation and hours constraints}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {3}, issn = {2628-653X}, doi = {10.25932/publishup-42765}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427656}, pages = {50}, year = {2019}, abstract = {The paper extends a static discrete-choice labor supply model by adding participation and hours constraints. We identify restrictions by survey information on the eligibility and search activities of individuals as well as actual and desired hours. This provides for a more robust identification of preferences and constraints. Both, preferences and restrictions are allowed to vary by and are related through observed and unobserved characteristics. We distinguish various restrictions mechanisms: labor demand rationing, working hours norms varying across occupations, and insufficient public childcare on the supply side of the market. The effect of these mechanisms is simulated by relaxing different constraints at a time. We apply the empirical frame- work to evaluate an in-work benefit for low-paid parents in the German institutional context. The benefit is supposed to increase work incentives for secondary earners. Based on the structural model we are able to disentangle behavioral reactions into the pure incentive effect and the limiting impact of constraints at the intensive and extensive margin. We find that the in-work benefit for parents substantially increases working hours of mothers of young children, especially when they have a low education. Simulating the effects of restrictions shows their substantial impact on employment of mothers with young children.}, language = {en} } @phdthesis{Solopow2019, author = {Solopow, Sergej}, title = {Wavelength dependent demagnetization dynamics in Co2MnGa Heusler-alloy}, doi = {10.25932/publishup-42786}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427860}, school = {Universit{\"a}t Potsdam}, pages = {91}, year = {2019}, abstract = {In dieser Arbeit haben wir ultraschnelle Entmagnetisierung an einer Heusler-Legierung untersucht. Es handelt sich um ein Halbmetall, das sich in einer ferromagnetischen Phase befindet. Die Besonderheit dieses Materials besteht im Aufbau einer Bandstruktur. Diese bildet Zustandsdichten, in der die Majorit{\"a}tselektronen eine metallische B{\"a}nderbildung aufweisen und die Minorit{\"a}tselektronen eine Bandl{\"u}cke in der N{\"a}he des Fermi-Niveaus aufweisen, das dem Aufbau eines Halbleiters entspricht. Mit Hilfe der Pump-Probe-Experimente haben wir zeitaufgel{\"o}ste Messungen durchgef{\"u}hrt. F{\"u}r das Pumpen wurden ultrakurze Laserpulse mit einer Pulsdauer von 100 fs benutzt. Wir haben dabei zwei verschiedene Wellenl{\"a}ngen mit 400 nm und 1240 nm benutzt, um den Effekt der Prim{\"a}ranregung und der Bandl{\"u}cke in den Minorit{\"a}tszust{\"a}nden zu untersuchen. Dabei wurde zum ersten Mal OPA (Optical Parametrical Amplifier) f{\"u}r die Erzeugung der langwelligen Pulse an der FEMTOSPEX-Beamline getestet und erfolgreich bei den Experimenten verwendet. Wir haben Wellenl{\"a}ngen bedingte Unterschiede in der Entmagnetisierungszeit gemessen. Mit der Erh{\"o}hung der Photonenenergie ist der Prozess der Entmagnetisierung deutlich schneller als bei einer niedrigeren Photonenenergie. Wir verkn{\"u}pften diese Ergebnisse mit der Existenz der Energiel{\"u}cke f{\"u}r Minorit{\"a}tselektronen. Mit Hilfe lokaler Elliot-Yafet-Streuprozesse k{\"o}nnen die beobachteten Zeiten gut erkl{\"a}rt werden. Wir haben in dieser Arbeit auch eine neue Probe-Methode f{\"u}r die Magnetisierung angewandt und somit experimentell deren Effektivit{\"a}t, n{\"a}mlich XMCD in Refletiongeometry, best{\"a}tigen k{\"o}nnen. Statische Experimente liefern somit deutliche Indizien daf{\"u}r, dass eine magnetische von einer rein elektronischen Antwort des Systems getrennt werden kann. Unter der Voraussetzung, dass die Photonenenergie der R{\"o}ntgenstrahlung auf die L3 Kante des entsprechenden Elements eingestellt, ein geeigneter Einfallswinkel gew{\"a}hlt und die zirkulare Polarisation fixiert wird, ist es m{\"o}glich, diese Methode zur Analyse magnetischer und elektronischer Respons anzuwenden.}, language = {en} } @phdthesis{Vietze2019, author = {Vietze, Jana}, title = {Social context as a resource for cultural belonging and adjustment}, school = {Universit{\"a}t Potsdam}, pages = {148}, year = {2019}, language = {en} } @misc{ChoiSchmidtTinnefeldetal.2019, author = {Choi, Youngeun and Schmidt, Carsten and Tinnefeld, Philip and Bald, Ilko and R{\"o}diger, Stefan}, title = {A new reporter design based on DNA origami nanostructures for quantification of short oligonucleotides using microbeads}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-naturwissenschaftliche Reihe}, number = {705}, issn = {1866-8372}, doi = {10.25932/publishup-42827}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428271}, pages = {8}, year = {2019}, abstract = {The DNA origami technique has great potential for the development of brighter and more sensitive reporters for fluorescence based detection schemes such as a microbead-based assay in diagnostic applications. The nanostructures can be programmed to include multiple dye molecules to enhance the measured signal as well as multiple probe strands to increase the binding strength of the target oligonucleotide to these nanostructures. Here we present a proof-of-concept study to quantify short oligonucleotides by developing a novel DNA origami based reporter system, combined with planar microbead assays. Analysis of the assays using the VideoScan digital imaging platform showed DNA origami to be a more suitable reporter candidate for quantification of the target oligonucleotides at lower concentrations than a conventional reporter that consists of one dye molecule attached to a single stranded DNA. Efforts have been made to conduct multiplexed analysis of different targets as well as to enhance fluorescence signals obtained from the reporters. We therefore believe that the quantification of short oligonucleotides that exist in low copy numbers is achieved in a better way with the DNA origami nanostructures as reporters.}, language = {en} } @article{ChoiSchmidtTinnefeldetal.2019, author = {Choi, Youngeun and Schmidt, Carsten and Tinnefeld, Philip and Bald, Ilko and R{\"o}diger, Stefan}, title = {A new reporter design based on DNA origami nanostructures for quantification of short oligonucleotides using microbeads}, series = {Scientific Reports}, journal = {Scientific Reports}, number = {9}, publisher = {Macmillan Publishers Limited}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-019-41136-x}, pages = {8}, year = {2019}, abstract = {The DNA origami technique has great potential for the development of brighter and more sensitive reporters for fluorescence based detection schemes such as a microbead-based assay in diagnostic applications. The nanostructures can be programmed to include multiple dye molecules to enhance the measured signal as well as multiple probe strands to increase the binding strength of the target oligonucleotide to these nanostructures. Here we present a proof-of-concept study to quantify short oligonucleotides by developing a novel DNA origami based reporter system, combined with planar microbead assays. Analysis of the assays using the VideoScan digital imaging platform showed DNA origami to be a more suitable reporter candidate for quantification of the target oligonucleotides at lower concentrations than a conventional reporter that consists of one dye molecule attached to a single stranded DNA. Efforts have been made to conduct multiplexed analysis of different targets as well as to enhance fluorescence signals obtained from the reporters. We therefore believe that the quantification of short oligonucleotides that exist in low copy numbers is achieved in a better way with the DNA origami nanostructures as reporters.}, language = {en} } @misc{HadzicEcksteinSchugardt2019, author = {Hadzic, Miralem and Eckstein, Max Lennart and Schugardt, Monique}, title = {The Impact of Sodium Bicarbonate on Performance in Response to Exercise Duration in Athletes}, series = {Potsprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Potsprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, number = {548}, issn = {1866-8364}, doi = {10.25932/publishup-42807}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428078}, pages = {11}, year = {2019}, abstract = {According to recent literature sodium bicarbonate (NaHCO3) has been proposed as a performance enhancing aid by reducing acidosis during exercise. The aim of the current review is to investigate if the duration of exercise is an essential factor for the effect of NaHCO3. To collect the latest studies from electronic database of PubMed, study publication time was restricted from December 2006 to December 2016. The search was updated in July 2018. The studies were divided into exercise durations of > 4 or ≤ 4 minutes for easier comparability of their effects in different exercises. Only randomized controlled trials were included in this review. Of the 775 studies, 35 met the inclusion criteria. Study design, subjects, effects as well as outcome criteria were inconsistent throughout the studies. Seventeen of these studies reported performance enhancing effects after supplementing NaHCO3. Eleven of twenty studies with exercise duration of ≤ 4 minutes showed positive and four diverse results after supplementing NaHCO3. On the other hand six of fifteen studies with an exercise duration of >4 minutes showed performance enhancing and two studies showed diverse results. Consequently, the duration of exercise might be influential for inducing a performance enhancing effect when supplementing NaHCO3, but to which extent, remains unclear due to the inconsistencies in the study results.}, language = {en} } @article{HadzicEckesteinSchugardt2019, author = {Hadzic, Miralem and Eckestein, Max Lennart and Schugardt, Monique}, title = {The Impact of Sodium Bicarbonate on Performance in Response to Exercise Duration in Athletes}, series = {Journal of sports science \& medicine : JSSM}, journal = {Journal of sports science \& medicine : JSSM}, number = {18}, publisher = {Department of Sports Medicine, Medical Faculty of Uludag University}, address = {Bursa, Turkey}, issn = {1303-2968}, pages = {271 -- 281}, year = {2019}, abstract = {According to recent literature sodium bicarbonate (NaHCO3) has been proposed as a performance enhancing aid by reducing acidosis during exercise. The aim of the current review is to investigate if the duration of exercise is an essential factor for the effect of NaHCO3. To collect the latest studies from electronic database of PubMed, study publication time was restricted from December 2006 to December 2016. The search was updated in July 2018. The studies were divided into exercise durations of > 4 or ≤ 4 minutes for easier comparability of their effects in different exercises. Only randomized controlled trials were included in this review. Of the 775 studies, 35 met the inclusion criteria. Study design, subjects, effects as well as outcome criteria were inconsistent throughout the studies. Seventeen of these studies reported performance enhancing effects after supplementing NaHCO3. Eleven of twenty studies with exercise duration of ≤ 4 minutes showed positive and four diverse results after supplementing NaHCO3. On the other hand six of fifteen studies with an exercise duration of >4 minutes showed performance enhancing and two studies showed diverse results. Consequently, the duration of exercise might be influential for inducing a performance enhancing effect when supplementing NaHCO3, but to which extent, remains unclear due to the inconsistencies in the study results.}, language = {en} } @techreport{BruttelStolleyUtikal2019, type = {Working Paper}, author = {Bruttel, Lisa Verena and Stolley, Florian and Utikal, Verena}, title = {Getting a Yes}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {2}, issn = {2628-653X}, doi = {10.25932/publishup-42763}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427638}, year = {2019}, abstract = {This paper studies how the request for a favor has to be devised in order to maximize its chance of success. We present results from a mini-dictator game, in which the recipient can send a free-form text message to the dictator before the latter decides. We find that putting effort into the message, writing in a humorous way and mentioning reasons why the money is needed pays off. Additionally, we find differences in the behavior of male and female dictators. Only men react positively to efficiency arguments, while only women react to messages that emphasize the dictator's power and responsibility.}, language = {en} } @misc{GrubicWierzba2019, author = {Grubic, Mira and Wierzba, Marta}, title = {Presupposition Accommodation of the German Additive Particle auch (= "too")}, series = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe}, number = {547}, issn = {1866-8364}, doi = {10.25932/publishup-42800}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-428003}, year = {2019}, abstract = {Presupposition triggers differ with respect to whether their presupposition is easily accommodatable. The presupposition of focus-sensitive additive particles like also or too is often classified as hard to accommodate, i.e., these triggers are infelicitous if their presupposition is not entailed by the immediate linguistic or non-linguistic context. We tested two competing accounts for the German additive particle auch concerning this requirement: First, that it requires a focus alternative to the whole proposition to be salient, and second, that it merely requires an alternative to the focused constituent (e.g., an individual) to be salient. We conducted two experiments involving felicity judgments as well as questions asking for the truth of the presupposition to be accommodated. Our results suggest that the latter account is too weak: mere previous mention of a potential alternative to the focused constituent is not enough to license the use of auch. However, our results also suggest that the former account is too strong: when an alternative of the focused constituent is prementioned and certain other accommodation-enhancing factors are present, the context does not have to entail the presupposed proposition. We tested the following two potentially accommodation-enhancing factors: First, whether the discourse can be construed to be from the perspective of the individual that the presupposition is about, and second, whether the presupposition is needed to establish coherence between the host sentence of the additive particle and the preceding context. The factor coherence was found to play a significant role. Our results thus corroborate the results of other researchers showing that discourse participants go to great lengths in order to identify a potential presupposition to accommodate, and we contribute to these results by showing that coherence is one of the factors that enhance accommodation.}, language = {en} } @article{GrubicWierzba2019, author = {Grubic, Mira and Wierzba, Marta}, title = {Presupposition Accommodation of the German Additive Particle auch (= "too")}, series = {Frontiers in Communication}, volume = {4}, journal = {Frontiers in Communication}, publisher = {Frontiers Media}, address = {Lausanne}, issn = {2297-900X}, doi = {10.3389/fcomm.2019.00015}, pages = {18}, year = {2019}, abstract = {Presupposition triggers differ with respect to whether their presupposition is easily accommodatable. The presupposition of focus-sensitive additive particles like also or too is often classified as hard to accommodate, i.e., these triggers are infelicitous if their presupposition is not entailed by the immediate linguistic or non-linguistic context. We tested two competing accounts for the German additive particle auch concerning this requirement: First, that it requires a focus alternative to the whole proposition to be salient, and second, that it merely requires an alternative to the focused constituent (e.g., an individual) to be salient. We conducted two experiments involving felicity judgments as well as questions asking for the truth of the presupposition to be accommodated. Our results suggest that the latter account is too weak: mere previous mention of a potential alternative to the focused constituent is not enough to license the use of auch. However, our results also suggest that the former account is too strong: when an alternative of the focused constituent is prementioned and certain other accommodation-enhancing factors are present, the context does not have to entail the presupposed proposition. We tested the following two potentially accommodation-enhancing factors: First, whether the discourse can be construed to be from the perspective of the individual that the presupposition is about, and second, whether the presupposition is needed to establish coherence between the host sentence of the additive particle and the preceding context. The factor coherence was found to play a significant role. Our results thus corroborate the results of other researchers showing that discourse participants go to great lengths in order to identify a potential presupposition to accommodate, and we contribute to these results by showing that coherence is one of the factors that enhance accommodation.}, language = {en} } @article{PilzDelgadoVossetal.2019, author = {Pilz, Tobias and Delgado, Jos{\´e} Miguel Martins and Voss, Sebastian and Vormoor, Klaus Josef and Francke, Till and Cunha Costa, Alexandre and Martins, Eduardo and Bronstert, Axel}, title = {Seasonal drought prediction for semiarid northeast Brazil}, series = {Hydrology and Earth System Sciences}, volume = {23}, journal = {Hydrology and Earth System Sciences}, publisher = {Copernicus Publications}, address = {G{\"o}ttingen}, issn = {1027-5606}, doi = {10.5194/hess-23-1951-2019}, pages = {1951 -- 1971}, year = {2019}, abstract = {The semiarid northeast of Brazil is one of the most densely populated dryland regions in the world and recurrently affected by severe droughts. Thus, reliable seasonal forecasts of streamflow and reservoir storage are of high value for water managers. Such forecasts can be generated by applying either hydrological models representing underlying processes or statistical relationships exploiting correlations among meteorological and hydrological variables. This work evaluates and compares the performances of seasonal reservoir storage forecasts derived by a process-based hydrological model and a statistical approach. Driven by observations, both models achieve similar simulation accuracies. In a hindcast experiment, however, the accuracy of estimating regional reservoir storages was considerably lower using the process-based hydrological model, whereas the resolution and reliability of drought event predictions were similar by both approaches. Further investigations regarding the deficiencies of the process-based model revealed a significant influence of antecedent wetness conditions and a higher sensitivity of model prediction performance to rainfall forecast quality. Within the scope of this study, the statistical model proved to be the more straightforward approach for predictions of reservoir level and drought events at regionally and monthly aggregated scales. However, for forecasts at finer scales of space and time or for the investigation of underlying processes, the costly initialisation and application of a process-based model can be worthwhile. Furthermore, the application of innovative data products, such as remote sensing data, and operational model correction methods, like data assimilation, may allow for an enhanced exploitation of the advanced capabilities of process-based hydrological models.}, language = {en} } @misc{PilzDelgadoVossetal.2019, author = {Pilz, Tobias and Delgado, Jos{\´e} Miguel Martins and Voss, Sebastian and Vormoor, Klaus Josef and Francke, Till and Cunha Costa, Alexandre and Martins, Eduardo and Bronstert, Axel}, title = {Seasonal drought prediction for semiarid northeast Brazil}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {702}, issn = {1866-8372}, doi = {10.25932/publishup-42795}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427950}, pages = {21}, year = {2019}, abstract = {The semiarid northeast of Brazil is one of the most densely populated dryland regions in the world and recurrently affected by severe droughts. Thus, reliable seasonal forecasts of streamflow and reservoir storage are of high value for water managers. Such forecasts can be generated by applying either hydrological models representing underlying processes or statistical relationships exploiting correlations among meteorological and hydrological variables. This work evaluates and compares the performances of seasonal reservoir storage forecasts derived by a process-based hydrological model and a statistical approach. Driven by observations, both models achieve similar simulation accuracies. In a hindcast experiment, however, the accuracy of estimating regional reservoir storages was considerably lower using the process-based hydrological model, whereas the resolution and reliability of drought event predictions were similar by both approaches. Further investigations regarding the deficiencies of the process-based model revealed a significant influence of antecedent wetness conditions and a higher sensitivity of model prediction performance to rainfall forecast quality. Within the scope of this study, the statistical model proved to be the more straightforward approach for predictions of reservoir level and drought events at regionally and monthly aggregated scales. However, for forecasts at finer scales of space and time or for the investigation of underlying processes, the costly initialisation and application of a process-based model can be worthwhile. Furthermore, the application of innovative data products, such as remote sensing data, and operational model correction methods, like data assimilation, may allow for an enhanced exploitation of the advanced capabilities of process-based hydrological models.}, language = {en} } @phdthesis{Weber2019, author = {Weber, Marie-Christin}, title = {Performance Enhancing Strategies in Different Negotiation Phases}, publisher = {Kovac}, address = {Hamburg}, isbn = {978-3-339-10946-0}, school = {Universit{\"a}t Potsdam}, pages = {78}, year = {2019}, abstract = {The present dissertation investigates profit-maximizing behavior in different phases of the negotiation process. Over the last decades, research dealt in detail with behavior of negotiation actors with the aim of identifying performance enhancing factors. The majority of those studies focused on behavior within the main negotiation phase. This work, however, considers phases which are, so far, underrepresented in research but show an impact on the negotiation process and outcome. Those phases are the pre-negotiation, the first offer, and the main negotiation phase which is further divided by breaks into several rounds. Within these phases, traits of behavior are analyzed that can be used strategically in order to impact the negotiation outcome. The dissertation contains three papers, each one dealing with a specific strategy within one phase. The first paper investigates communication behavior in the pre-negotiation phase. Content analysis of a negotiation experiment shows that the employment of positive communication elements such as the generation of enthusiasm for an upcoming project results in an increase of agreements on entering a negotiation and also leads to a higher willingness to make concessions. The second paper explores the impact of a semantic first anchor, which does not contain a specific number but only gives a numerical direction, on the opponent's concession behavior and the final outcome. By means of two scenario-based questionnaires and a negotiation experiment it is demonstrated that semantic offers reveal an anchoring effect and lead to better negotiation outcomes. The third paper deals with the introduction of breaks and their effect on the following negotiation process. Therefore, content and outcome of another negotiation experiment are investigated. The analysis shows that breaks evoke a dominant impression but can negatively impact the atmosphere and thereby also the outcome. Finally, the gathered insights are brought together and discussed. The dissertation closes with implications for practice, limitations of the work, and ideas for future research.}, language = {en} } @misc{AbbasVranicHoffmannetal.2019, author = {Abbas, Ioana M. and Vranic, Marija and Hoffmann, Holger and El-Khatib, Ahmed H. and Montes-Bay{\´o}n, Mar{\´i}a and M{\"o}ller, Heiko Michael and Weller, Michael G.}, title = {Investigations of the Copper Peptide Hepcidin-25 by LC-MS/MS and NMR⁺}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {701}, issn = {1866-8372}, doi = {10.25932/publishup-42792}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427926}, year = {2019}, abstract = {Hepcidin-25 was identified as themain iron regulator in the human body, and it by binds to the sole iron-exporter ferroportin. Studies showed that the N-terminus of hepcidin is responsible for this interaction, the same N-terminus that encompasses a small copper(II) binding site known as the ATCUN (amino-terminal Cu(II)- and Ni(II)-binding) motif. Interestingly, this copper-binding property is largely ignored in most papers dealing with hepcidin-25. In this context, detailed investigations of the complex formed between hepcidin-25 and copper could reveal insight into its biological role. The present work focuses on metal-bound hepcidin-25 that can be considered the biologically active form. The first part is devoted to the reversed-phase chromatographic separation of copper-bound and copper-free hepcidin-25 achieved by applying basic mobile phases containing 0.1\% ammonia. Further, mass spectrometry (tandemmass spectrometry (MS/MS), high-resolutionmass spectrometry (HRMS)) and nuclear magnetic resonance (NMR) spectroscopy were employed to characterize the copper-peptide. Lastly, a three-dimensional (3D)model of hepcidin-25with bound copper(II) is presented. The identification of metal complexes and potential isoforms and isomers, from which the latter usually are left undetected by mass spectrometry, led to the conclusion that complementary analytical methods are needed to characterize a peptide calibrant or referencematerial comprehensively. Quantitative nuclear magnetic resonance (qNMR), inductively-coupled plasma mass spectrometry (ICP-MS), ion-mobility spectrometry (IMS) and chiral amino acid analysis (AAA) should be considered among others.}, language = {en} } @misc{SpiekermannHarderGilmoreetal.2019, author = {Spiekermann, Georg and Harder, M. and Gilmore, Keith and Zalden, Peter and Sahle, Christoph J. and Petitgirard, Sylvain and Wilke, Max and Biedermann, Nicole and Weis, Thomas and Morgenroth, Wolfgang and Tse, John S. and Kulik, E. and Nishiyama, Norimasa and Yava{\c{s}}, Hasan and Sternemann, Christian}, title = {Persistent Octahedral Coordination in Amorphous GeO₂ Up to 100 GPa by Kβ'' X-Ray Emission Spectroscopy}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {699}, issn = {1866-8372}, doi = {10.25932/publishup-42775}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427755}, year = {2019}, abstract = {We measure valence-to-core x-ray emission spectra of compressed crystalline GeO₂ up to 56 GPa and of amorphous GeO₂ up to 100 GPa. In a novel approach, we extract the Ge coordination number and mean Ge-O distances from the emission energy and the intensity of the Kβ'' emission line. The spectra of high-pressure polymorphs are calculated using the Bethe-Salpeter equation. Trends observed in the experimental and calculated spectra are found to match only when utilizing an octahedral model. The results reveal persistent octahedral Ge coordination with increasing distortion, similar to the compaction mechanism in the sequence of octahedrally coordinated crystalline GeO₂ high-pressure polymorphs.}, language = {en} } @article{SpiekermannHarderGilmoreetal.2019, author = {Spiekermann, Georg and Harder, M. and Gilmore, Keith and Zalden, Peter and Sahle, Christoph J. and Petitgirard, Sylvain and Wilke, Max and Biedermann, Nicole and Weis, Thomas and Morgenroth, Wolfgang and Tse, John S. and Kulik, E. and Nishiyama, Norimasa and Yava{\c{s}}, Hasan and Sternemann, Christian}, title = {Persistent Octahedral Coordination in Amorphous GeO₂ Up to 100 GPa by Kβ'' X-Ray Emission Spectroscopy}, series = {Physical Review X}, volume = {9}, journal = {Physical Review X}, number = {1}, publisher = {American Physical Society by the American Institute of Physics}, address = {Melville, NY}, issn = {2469-9926}, doi = {10.1103/PhysRevX.9.011025}, pages = {10}, year = {2019}, abstract = {We measure valence-to-core x-ray emission spectra of compressed crystalline GeO₂ up to 56 GPa and of amorphous GeO₂ up to 100 GPa. In a novel approach, we extract the Ge coordination number and mean Ge-O distances from the emission energy and the intensity of the Kβ'' emission line. The spectra of high-pressure polymorphs are calculated using the Bethe-Salpeter equation. Trends observed in the experimental and calculated spectra are found to match only when utilizing an octahedral model. The results reveal persistent octahedral Ge coordination with increasing distortion, similar to the compaction mechanism in the sequence of octahedrally coordinated crystalline GeO₂ high-pressure polymorphs.}, language = {en} } @phdthesis{Farhan2019, author = {Farhan, Muhammad}, title = {Multifunctional reprogrammable actuators based on polymer networks with crystallizable segments}, school = {Universit{\"a}t Potsdam}, year = {2019}, abstract = {Soft polymeric materials, which can change their shape reversibly in response to external stimuli, can serve as actuating components in robotic systems. Besides electroactive polymers (EAP), hydrogels and liquid crystalline elastomers (LCE), crosslinked crystallizable shape-memory polymers networks have been introduced recently as reprogrammable thermo-reversible actuators. The integration of additional functions in such materials will lead to multifunctional polymeric actuators, which meet the complex requirements of modern robotic applications. The primary aim of this thesis was to achieve multifunctional reprogrammable thermo-reversible actuators based on thermoplastic polymers. Here, three different actuators providing additional functionalities such as surface modification capability (i), self-healing capability (ii) or a tailorable non-response function enabling noncontinuous multi-step motions (iii) were realized. At first, it was hypothesized that surface modifiable polymeric actuators (i) can be achieved by crosslinking of crystallizable thermoplastic terpolymers having reactive moieties, where subsequent thermomechanical programming enables reversible actuations while the sustained reactive groups allow post surface modification. For the second actuator type (ii) it was hypothesized that self-healing during reprogramming of polymeric actuators prepared by crosslinking of crystallizable linear homopolymers, can be achieved by adjusting the amount of freely interpenetrating extractable polymer moieties. Finally, it was hypothesized that thermo-reversible actuators providing a non-response function (iii) and thus enable multistep motions upon continuous normal stimulation, can be achieved by a crosslinked blend of two thermoplastic polymers with co-continuous morphology having a well-separated melting and crystallization transitions. In addition, these actuators can be physically reprogrammed by heating above all melting transitions to provide a different actuating shape. In this study, surface functionalizable actuators were realized from crosslinked poly[(ethylene)-co-(ethyl acrylate)-co-(maleic anhydride)] (cPEEAMA) based networks. Here crystallizable polyethylene (PE) segments should serve as actuation segments, ethyl acrylate (EA) provides elasticity to the system required for deformation, while reactive maleic anhydride (MA) will be used as chemically modifiable entities for post surface modification. Networks with varied crosslink density were prepared and its effect on thermomechanical properties as well as actuation performance was analyzed. Cyclic thermomechanical experiments were employed to investigate the actuation capability, which revealed a reversible actuation (ε׳rev) between 5 and 15\%. Fourier-transform infrared spectroscopy (FTIR) measurements confirmed that MA groups were sustained at the sample surface after processing and programming, which could be modified by reaction with ethylene diamine. Such amine functionalization allows the attachment of bioactive molecules to the actuator surface, which might provide a route to actuating substrates for biotechnology. Self-healable actuating materials were realized by poly(ε-caprolactone) (PCL) polymer networks with extractable linear PCL fractions of 5 to 60 wt\%. A detailed evaluation of the actuation capabilities by cyclic experiments revealed the highest reversible change in strain of Δε = 24\% for the cPCL network with 30 wt\% of linear polymer. The thermal treatment of damaged samples resulted in the healing of the network when heated to 80 °C. Here a linear polymer fraction ≥ 30 wt\% was necessary to achieve a self-healing efficiency of ≥ 50\%. The application of such high temperatures erases the programmed actuator shape and at the same time allows to reprogram a new actuating shape. Such sustainable actuators with self-healing function are of great interest for future robotic devices. Afore mentioned actuators operate continuously between two shapes and their movements can only be interrupted when the temperature is stopped. To overcome this limitation, noncontinuously responding actuators enabling multi-step actuation were realized from crosslinked blend networks prepared from PCL and poly[(ethylene)-co-(vinyl acetate)] (PEVA). These polymers (PCL and PEVA) were selected due to their immiscible character, where crystallizable PE and PCL segments provide two different actuation units, while vinyl acetate (VA) segment enabled sufficient elasticity of the system. A gap of 20 K in the melting and crystallization temperature of PE and PCL was achieved by selecting PEVA with 5 wt\% VA content (cPCL-PEVA5) providing a co-continuous phase morphology. Cyclic thermomechanical investigations were employed to investigate noncontinuous actuation, which revealed a high Δε = 25\% with a similar contribution from PCL and PE actuation units with a non-response region in the temperature range from 50 to 71 °C in heating step and 30 to 60 °C in cooling step. The actuation related to PCL part changed from 13 to 2\% by altering the heating and cooling rates from 3 to 10 K·min-1. Free-standing reversible noncontinuous actuation was realized by rotating demonstrator which exhibits reversible angle change in a custom-made setup. For this purpose, cPCL-PEVA5 stripe was programmed by twisting and reversible rotational actuation was realized from 0 to 180° while pausing in the 90° position during non-response. These blends can be physically programmed to perform reversible noncontinuous actuations, while the programmed geometry can be erased by heating it to temperature above all melting transitions. By physically reprogramming of the material various different actuation modes can be obtained. Such a noncontinuous actuator would be relevant for designing interruptive actuating soft robots at continuous trigger signals.}, language = {en} } @phdthesis{Lefebvre2019, author = {Lefebvre, Marie G.}, title = {Two stages of skarn formation - two tin enrichments}, doi = {10.25932/publishup-42717}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427178}, school = {Universit{\"a}t Potsdam}, pages = {87}, year = {2019}, abstract = {Skarn deposits are found on every continents and were formed at different times from Precambrian to Tertiary. Typically, the formation of a skarn is induced by a granitic intrusion in carbonates-rich sedimentary rocks. During contact metamorphism, fluids derived from the granite interact with the sedimentary host rocks, which results in the formation of calc-silicate minerals at the expense of carbonates. Those newly formed minerals generally develop in a metamorphic zoned aureole with garnet in the proximal and pyroxene in the distal zone. Ore elements contained in magmatic fluids are precipitated due to the change in fluid composition. The temperature decrease of the entire system, due to the cooling of magmatic fluids and the entering of meteoric water, allows retrogression of some prograde minerals. The H{\"a}mmerlein skarn deposit has a multi-stage history with a skarn formation during regional metamorphism and a retrogression of primary skarn minerals during the granitic intrusion. Tin was mobilized during both events. The 340 Ma old tin-bearing skarn minerals show that tin was present in sediments before the granite intrusion, and that the first Sn enrichment occurred during the skarn formation by regional metamorphism fluids. In a second step at ca. 320 Ma, tin-bearing fluids were produced with the intrusion of the Eibenstock granite. Tin, which has been added by the granite and remobilized from skarn calc-silicates, precipitated as cassiterite. Compared to clay or marl, the skarn is enriched in Sn, W, In, Zn, and Cu. These metals have been supplied during both regional metamorphism and granite emplacement. In addition, the several isotopic and chemical data of skarn samples show that the granite selectively added elements such as Sn, and that there was no visible granitic contribution to the sedimentary signature of the skarn The example of H{\"a}mmerlein shows that it is possible to form a tin-rich skarn without associated granite when tin has already been transported from tin-bearing sediments during regional metamorphism by aqueous metamorphic fluids. These skarns are economically not interesting if tin is only contained in the skarn minerals. Later alteration of the skarn (the heat and fluid source is not necessarily a granite), however, can lead to the formation of secondary cassiterite (SnO2), with which the skarn can become economically highly interesting.}, 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} } @techreport{CaliendoSchroederWittbrodt2019, type = {Working Paper}, author = {Caliendo, Marco and Schr{\"o}der, Carsten and Wittbrodt, Linda}, title = {The Causal Effects of the Minimum Wage Introduction in Germany}, series = {CEPA Discussion Papers}, journal = {CEPA Discussion Papers}, number = {1}, issn = {2628-653X}, doi = {10.25932/publishup-42692}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426929}, year = {2019}, abstract = {In 2015, Germany introduced a statutory hourly minimum wage that was not only universally binding but also set at a relatively high level. We discuss the short-run effects of this new minimum wage on a wide set of socio-economic outcomes, such as employment and working hours, earnings and wage inequality, dependent and self-employment, as well as reservation wages and satisfaction. We also discuss difficulties in the implementation of the minimum wage and the measurement of its effects related to non-compliance and suitability of data sources. Two years after the minimum wage introduction, the following conclusions can be drawn: while hourly wages increased for low-wage earners, some small negative employment effects are also identifiable. The effects on aspired goals, such as poverty and inequality reduction, have not materialized in the short run. Instead, a tendency to reduce working hours is found, which alleviates the desired positive impact on monthly income. Additionally, the level of non-compliance was substantial in the short run, thus drawing attention to problems when implementing such a wide-reaching policy.}, language = {en} } @article{LonnemannLiZhaoetal.2019, author = {Lonnemann, Jan and Li, Su and Zhao, Pei and Linkersd{\"o}rfer, Janosch and Lindberg, Sven and Hasselhorn, Marcus}, title = {Differences in Counting Skills Between Chinese and German Children Are Accompanied by Differences in Processing of Approximate Numerical Magnitude Information}, series = {Frontiers in Psychology}, volume = {9}, journal = {Frontiers in Psychology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2018.02656}, pages = {8}, year = {2019}, abstract = {Human beings are supposed to possess an approximate number system (ANS) dedicated to extracting and representing approximate numerical magnitude information as well as an object tracking system (OTS) for the rapid and accurate enumeration of small sets. It is assumed that the OTS and the ANS independently contribute to the acquisition of more elaborate numerical concepts. Chinese children have been shown to exhibit more elaborate numerical concepts than their non-Chinese peers, but it is still an open question whether similar cross-national differences exist with regard to the underlying systems, namely the ANS and the OTS. In the present study, we investigated this question by comparing Chinese and German preschool children with regard to their performance in a non-symbolic numerical magnitude comparison task (assessing the ANS) and in an enumeration task (assessing the OTS). In addition, we compared children's counting skills. To ensure that possible between-group differences could not be explained by differences in more general performance factors, we also assessed children's reasoning ability and processing speed. Chinese children showed a better counting performance and a more accurate performance in the non-symbolic numerical magnitude comparison task. These differences in performance could not be ascribed to differences in reasoning abilities and processing speed. In contrast, Chinese and German children did not differ significantly in the enumeration of small sets. The superior counting performance of Chinese children was thus found to be reflected in the ANS but not in the OTS.}, language = {en} } @misc{FayUrbachScheithauer2019, author = {Fay, Doris and Urbach, Tina and Scheithauer, Linda}, title = {What motivates you right now?}, series = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe}, number = {545}, issn = {1866-8364}, doi = {10.25932/publishup-42735}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427350}, pages = {17}, year = {2019}, abstract = {Regulatory focus is a motivational construct that describes humans' motivational orientation during goal pursuit. It is conceptualized as a chronic, trait-like, as well as a momentary, state-like orientation. Whereas there is a large number of measures to capture chronic regulatory focus, measures for its momentary assessment are only just emerging. This paper presents the development and validation of a measure of Momentary-Chronic Regulatory Focus. Our development incorporates the distinction between self-guide and reference-point definitions of regulatory focus. Ideals and ought striving are the promotion and prevention dimension in the self-guide system; gain and non-loss regulatory focus are the respective dimensions within the reference-point system. Three-survey-based studies test the structure, psychometric properties, and validity of the measure in its version to assess chronic regulatory focus (two samples of working participants, N = 389, N = 672; one student sample [time 1, N = 105; time 2, n = 91]). In two further studies, an experience sampling study with students (N = 84, k = 1649) and a daily-diary study with working individuals (N = 129, k = 1766), the measure was applied to assess momentary regulatory focus. Multilevel analyses test the momentary measure's factorial structure, provide support for its sensitivity to capture within-person fluctuations, and provide evidence for concurrent construct validity.}, language = {en} } @article{FayUrbachScheithauer2019, author = {Fay, Doris and Urbach, Tina and Scheithauer, Linda}, title = {What motivates you right now?}, series = {Measurement Instruments for the Social Sciences}, volume = {2}, journal = {Measurement Instruments for the Social Sciences}, number = {5}, publisher = {BioMed Central}, address = {London}, issn = {2523-8930}, doi = {10.1186/s42409-019-0007-7}, pages = {17}, year = {2019}, abstract = {Regulatory focus is a motivational construct that describes humans' motivational orientation during goal pursuit. It is conceptualized as a chronic, trait-like, as well as a momentary, state-like orientation. Whereas there is a large number of measures to capture chronic regulatory focus, measures for its momentary assessment are only just emerging. This paper presents the development and validation of a measure of Momentary-Chronic Regulatory Focus. Our development incorporates the distinction between self-guide and reference-point definitions of regulatory focus. Ideals and ought striving are the promotion and prevention dimension in the self-guide system; gain and non-loss regulatory focus are the respective dimensions within the reference-point system. Three-survey-based studies test the structure, psychometric properties, and validity of the measure in its version to assess chronic regulatory focus (two samples of working participants, N = 389, N = 672; one student sample [time 1, N = 105; time 2, n = 91]). In two further studies, an experience sampling study with students (N = 84, k = 1649) and a daily-diary study with working individuals (N = 129, k = 1766), the measure was applied to assess momentary regulatory focus. Multilevel analyses test the momentary measure's factorial structure, provide support for its sensitivity to capture within-person fluctuations, and provide evidence for concurrent construct validity.}, language = {en} } @misc{WrightWachs2019, author = {Wright, Michelle F. and Wachs, Sebastian}, title = {Does Peer Rejection Moderate the Associations among Cyberbullying Victimization, Depression, and Anxiety among Adolescents with Autism Spectrum Disorder?}, series = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe}, doi = {10.25932/publishup-42726}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427266}, pages = {12}, year = {2019}, abstract = {While the consequences of cyberbullying victimization have received some attention in the literature, to date, little is known about the multiple types of strains in adolescents' lives, such as whether cyberbullying victimization and peer rejection increase their vulnerability to depression and anxiety. Even though some research found that adolescents with disabilities show higher risk for cyberbullying victimization, most research has focused on typically developing adolescents. Thus, the present study focused on examining the moderating effect of peer rejection in the relationships between cyberbullying victimization, depression, and anxiety among adolescents with autism spectrum disorder. There were 128 participants (89\% male; ages ranging from 11-16 years old) with autism spectrum disorder in the sixth, seventh, or eighth grade at 16 middle schools in the United States. Participants completed questionnaires on cyberbullying victimization, peer rejection, depression, and anxiety. Results revealed that cyberbullying victimization was associated positively with peer rejection, anxiety, and depression among adolescents with autism spectrum disorder. Further, peer rejection was linked positively with depression and anxiety. Peer rejection moderated the positive relationship between cyberbullying victimization and depression, but not anxiety. Implications for prevention programs and future research are discussed.}, language = {en} } @article{WrightWachs2019, author = {Wright, Michelle F. and Wachs, Sebastian}, title = {Does Peer Rejection Moderate the Associations among Cyberbullying Victimization, Depression, and Anxiety among Adolescents with Autism Spectrum Disorder?}, series = {Children}, volume = {6}, journal = {Children}, publisher = {MDPI}, address = {Basel}, issn = {2227-9067}, doi = {10.3390/children6030041}, pages = {12}, year = {2019}, abstract = {While the consequences of cyberbullying victimization have received some attention in the literature, to date, little is known about the multiple types of strains in adolescents' lives, such as whether cyberbullying victimization and peer rejection increase their vulnerability to depression and anxiety. Even though some research found that adolescents with disabilities show higher risk for cyberbullying victimization, most research has focused on typically developing adolescents. Thus, the present study focused on examining the moderating effect of peer rejection in the relationships between cyberbullying victimization, depression, and anxiety among adolescents with autism spectrum disorder. There were 128 participants (89\% male; ages ranging from 11-16 years old) with autism spectrum disorder in the sixth, seventh, or eighth grade at 16 middle schools in the United States. Participants completed questionnaires on cyberbullying victimization, peer rejection, depression, and anxiety. Results revealed that cyberbullying victimization was associated positively with peer rejection, anxiety, and depression among adolescents with autism spectrum disorder. Further, peer rejection was linked positively with depression and anxiety. Peer rejection moderated the positive relationship between cyberbullying victimization and depression, but not anxiety. Implications for prevention programs and future research are discussed.}, language = {en} } @misc{KalinowskiGronostajVock2019, author = {Kalinowski, Eva and Gronostaj, Anna and Vock, Miriam}, title = {Effective Professional Development for Teachers to Foster Students' Academic Language Proficiency Across the Curriculum}, series = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe}, number = {543}, issn = {1866-8364}, doi = {10.25932/publishup-42721}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-427219}, pages = {23}, year = {2019}, abstract = {This review summarizes features of professional development programs that aim to prepare in-service teachers to improve students' academic language proficiency when teaching subject areas. The 38 studies reviewed suggest that all of the profiled interventions were effective to some extent. The programs share many characteristics considered important in successful teacher professional development across different subject areas. They also include some features that appear to be specific to teacher training in this particular domain. This review supports the idea that professional development helps change teachers' thinking and practice and benefits students, if certain features are taken into consideration in its design and implementation.}, language = {en} } @article{KalinowskiGronostajVock2019, author = {Kalinowski, Eva and Gronostaj, Anna and Vock, Miriam}, title = {Effective Professional Development for Teachers to Foster Students' Academic Language Proficiency Across the Curriculum}, series = {AERA Open}, volume = {5}, journal = {AERA Open}, number = {1}, publisher = {Sage}, address = {Thousand Oaks}, issn = {2332-8584}, doi = {10.1177/2332858419828691}, pages = {1 -- 23}, year = {2019}, abstract = {This review summarizes features of professional development programs that aim to prepare in-service teachers to improve students' academic language proficiency when teaching subject areas. The 38 studies reviewed suggest that all of the profiled interventions were effective to some extent. The programs share many characteristics considered important in successful teacher professional development across different subject areas. They also include some features that appear to be specific to teacher training in this particular domain. This review supports the idea that professional development helps change teachers' thinking and practice and benefits students, if certain features are taken into consideration in its design and implementation.}, language = {en} } @article{SarhanKoopmanSchuetzetal.2019, author = {Sarhan, Radwan Mohamed and Koopman, Wouter-Willem Adriaan and Schuetz, Roman and Schmid, Thomas and Liebig, Ferenc and Koetz, Joachim and Bargheer, Matias}, title = {The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol}, series = {Scientific Reports}, volume = {9}, journal = {Scientific Reports}, publisher = {Macmillan Publishers Limited}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-019-38627-2}, pages = {8}, year = {2019}, abstract = {Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding.}, language = {en} } @phdthesis{Raatz2019, author = {Raatz, Michael}, title = {Strategies within predator-prey interactions - from individuals to ecosystems}, doi = {10.25932/publishup-42658}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426587}, school = {Universit{\"a}t Potsdam}, pages = {175}, year = {2019}, abstract = {Predator-prey interactions provide central links in food webs. These interaction are directly or indirectly impacted by a number of factors. These factors range from physiological characteristics of individual organisms, over specifics of their interaction to impacts of the environment. They may generate the potential for the application of different strategies by predators and prey. Within this thesis, I modelled predator-prey interactions and investigated a broad range of different factors driving the application of certain strategies, that affect the individuals or their populations. In doing so, I focused on phytoplankton-zooplankton systems as established model systems of predator-prey interactions. At the level of predator physiology I proposed, and partly confirmed, adaptations to fluctuating availability of co-limiting nutrients as beneficial strategies. These may allow to store ingested nutrients or to regulate the effort put into nutrient assimilation. We found that these two strategies are beneficial at different fluctuation frequencies of the nutrients, but may positively interact at intermediate frequencies. The corresponding experiments supported our model results. We found that the temporal structure of nutrient fluctuations indeed has strong effects on the juvenile somatic growth rate of {\itshape Daphnia}. Predator colimitation by energy and essential biochemical nutrients gave rise to another physiological strategy. High-quality prey species may render themselves indispensable in a scenario of predator-mediated coexistence by being the only source of essential biochemical nutrients, such as cholesterol. Thereby, the high-quality prey may even compensate for a lacking defense and ensure its persistence in competition with other more defended prey species. We found a similar effect in a model where algae and bacteria compete for nutrients. Now, being the only source of a compound that is required by the competitor (bacteria) prevented the competitive exclusion of the algae. In this case, the essential compounds were the organic carbon provided by the algae. Here again, being indispensable served as a prey strategy that ensured its coexistence. The latter scenario also gave rise to the application of the two metabolic strategies of autotrophy and heterotrophy by algae and bacteria, respectively. We found that their coexistence allowed the recycling of resources in a microbial loop that would otherwise be lost. Instead, these resources were made available to higher trophic levels, increasing the trophic transfer efficiency in food webs. The predation process comprises the next higher level of factors shaping the predator-prey interaction, besides these factors that originated from the functioning or composition of individuals. Here, I focused on defensive mechanisms and investigated multiple scenarios of static or adaptive combinations of prey defense and predator offense. I confirmed and extended earlier reports on the coexistence-promoting effects of partially lower palatability of the prey community. When bacteria and algae are coexisting, a higher palatability of bacteria may increase the average predator biomass, with the side effect of making the population dynamics more regular. This may facilitate experimental investigations and interpretations. If defense and offense are adaptive, this allows organisms to maximize their growth rate. Besides this fitness-enhancing effect, I found that co-adaptation may provide the predator-prey system with the flexibility to buffer external perturbations. On top of these rather internal factors, environmental drivers also affect predator-prey interactions. I showed that environmental nutrient fluctuations may create a spatio-temporal resource heterogeneity that selects for different predator strategies. I hypothesized that this might favour either storage or acclimation specialists, depending on the frequency of the environmental fluctuations. We found that many of these factors promote the coexistence of different strategies and may therefore support and sustain biodiversity. Thus, they might be relevant for the maintenance of crucial ecosystem functions that also affect us humans. Besides this, the richness of factors that impact predator-prey interactions might explain why so many species, especially in the planktonic regime, are able to coexist.}, language = {en} } @phdthesis{PerlazaJimenez2019, author = {Perlaza-Jimenez, Laura}, title = {Discerning functional associations and relationships between molecules in Arabidopsis thaliana using genome-wide correlated mutations}, school = {Universit{\"a}t Potsdam}, pages = {118}, year = {2019}, 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} } @techreport{Krieger2019, type = {Working Paper}, author = {Krieger, Heike}, title = {Populist governments and international law}, series = {KFG Working Paper Series}, journal = {KFG Working Paper Series}, number = {29}, doi = {10.25932/publishup-42686}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-426863}, pages = {29}, year = {2019}, abstract = {The worldwide populist wave has contributed to a perception that international law is currently in a state of crisis. This article examines in how far populist governments have challenged prevailing interpretations of international law. The article links structural features of populism with an analysis of populist governmental strategies and argumentative practices. It demonstrates that, in their rhetoric, populist governments promote an understanding of international law as a mere law of coordination. This is, however, not entirely reflected in their legal practices where an instrumental, cherry-picking approach prevails. The article concludes that policies of populist governments affect the current state of international law on two different levels: In the political sphere their practices alter the general environment in which legal rules are interpreted. In the legal sphere populist governments push for changes in the interpretation of established international legal rules. The article substantiates these propositions by focusing on the principle of nonintervention and foreign funding for NGOs.}, language = {en} }