TY - JOUR A1 - Siegel, Björn T1 - “They Took to the Sea” – Jewish History and Culture in Maritime Perspective(s) JF - PaRDeS : Journal of the Association for Jewish Studies in Germany JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien e.V. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-585509 SN - 978-3-86956-552-1 SN - 1614-6492 SN - 1862-7684 IS - 28 SP - 11 EP - 16 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Schlör, Joachim T1 - “Israel am Meere” BT - The Sea Voyage as a Place and Time for Questions about Jewish Identity JF - PaRDeS : Journal of the Association for Jewish Studies in Germany JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien e.V. N2 - For Jews in Germany, the period following the Nazis’ rise to power in January 1933 was a period of decision-making on many levels: How should they respond to the persecution? If they decided to emigrate, many more decisions had to be made: How does one leave a country, and where should one go? A key moment in the process and in the cultural practice of emigration is the beginning of the sea voyage – when the need for departure and the hope for a new arrival jointly create a period of liminality. Looking at reports from sea voyages of exploration and emigration from the 1930s, this contribution discusses the question whether, and in what ways, such reflections can be read in the context of religious experiences and in the search for Jewish identities in times of turmoil. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-585537 SN - 978-3-86956-552-1 SN - 1614-6492 SN - 1862-7684 IS - 28 SP - 18 EP - 32 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Siegel, Björn T1 - “Creating a Maritime Future” BT - Hamburg and the Revival of Jewish Seafaring and Fishing Traditions in the 1940s and 1950s JF - PaRDeS : Journal of the Association for Jewish Studies in Germany JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien e.V. N2 - This article explores the importance of the port city of Hamburg in the evolving discourses on the creation of a maritime future, a vision which became influential in the 1930s, 1940s and 1950s. While some Jewish representatives in the city aimed at preserving and intertwining Hanseatic and Jewish traditions in order to secure a Jewish presence in the port city under the pressure of the Nazi regime and thereafter, others wanted to create new emigration opportunities, especially to Mandatory Palestine, and create a Jewish maritime future in Eretz Israel. Different Zionist organizations supported the newly evolving maritime ideas, such as the “conquest of the sea”, and promoted the image of a Jewish seafaring nation. Despite the difficulties in the 1940s, these concepts gained influence post-1945 and led to the foundation of the fishery kibbutz “Zerubavel” in Blankenese/Hamburg. However, the idea of a Hanseatic Jewish future also remained influential and illustrates how differently a “Jewish maritime future” was imagined and used to link past, present and future. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-585575 SN - 978-3-86956-552-1 SN - 1614-6492 SN - 1862-7684 IS - 28 SP - 68 EP - 82 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Barth-Weingarten, Dagmar A1 - Ogden, Richard T1 - “Chunking” spoken language BT - Introducing weak cesuras JF - Open linguistics N2 - In this introductory paper to the special issue on “Weak cesuras in talk-in-interaction”, we aim to guide the reader into current work on the “chunking” of naturally occurring talk. It is conducted in the methodological frameworks of Conversation Analysis and Interactional Linguistics – two approaches that consider the interactional aspect of humans talking with each other to be a crucial starting point for its analysis. In doing so, we will (1) lay out the background of this special issue (what is problematic about “chunking” talk-in-interaction, the characteristics of the methodological approach chosen by the contributors, the cesura model), (2) highlight what can be gained from such a revised understanding of “chunking” in talk-in-interaction by referring to previous work with this model as well as the findings of the contributions to this special issue, and (3) indicate further directions such work could take starting from papers in this special issue. We hope to induce a fruitful exchange on the phenomena discussed, across methodological divides. KW - Conversation Analysis KW - Interactional Linguistics KW - prosody KW - phonetics KW - intonation units KW - talk-in-interaction KW - syntax KW - kinetics Y1 - 2021 U6 - https://doi.org/10.1515/opli-2020-0173 SN - 2300-9969 VL - 7 IS - 1 SP - 531 EP - 548 PB - De Gruyter CY - Berlin ER - TY - JOUR A1 - Gallas, Elisabeth A1 - Rürup, Miriam T1 - “Advocate of the Jewish People” BT - Nehemia Robinson’s Legal Activism after 1945 : An Introduction JF - PaRDeS : Journal of the Association for Jewish Studies in Germany JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien KW - Modern Jewish history KW - United States KW - legal history KW - 20th century KW - Nehemia Robinson KW - German history KW - moderne jüdische Geschichte KW - USA KW - Rechtsgeschichte KW - 20. Jahrhundert KW - Nehemia Robinson KW - deutsche Geschichte Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-537501 SN - 978-3-86956-520-0 SN - 1614-6492 SN - 1862-7684 IS - 27 SP - 135 EP - 142 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - CHAP A1 - Gebser, Martin A1 - Hinrichs, Henrik A1 - Schaub, Torsten H. A1 - Thiele, Sven T1 - xpanda: a (simple) preprocessor for adding multi-valued propositions to ASP N2 - We introduce a simple approach extending the input language of Answer Set Programming (ASP) systems by multi-valued propositions. Our approach is implemented as a (prototypical) preprocessor translating logic programs with multi-valued propositions into logic programs with Boolean propositions only. Our translation is modular and heavily benefits from the expressive input language of ASP. The resulting approach, along with its implementation, allows for solving interesting constraint satisfaction problems in ASP, showing a good performance. Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-41466 ER - TY - CHAP A1 - Raassen, A. J. J. A1 - Hucht, K. A. van der A1 - Miller, N. A. A1 - Cassinelli, Joseph P. T1 - XMM-Newton observations of zeta Orionis (O9.7 Ib) : a collisional ionization equilibrium model N2 - We present the analysis of XMM-Newton observations of ζ Orionis. The analysis is based on fitting to the total spectrum as well as diagnostics of individual line. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17747 ER - TY - CHAP A1 - Cassinelli, Joseph P. A1 - Ignace, R. A1 - Waldron, W. A1 - Cho, J. A1 - Murphy, N. A1 - Lazarian, A. T1 - X-ray line emission produced in clump bow shocks N2 - We summarize Chandra observations of the emission line profiles from 17 OB stars. The lines tend to be broad and unshifted. The forbidden/intercombination line ratios arising from Helium-like ions provide radial distance information for the X-ray emission sources, while the H-like to He-like line ratios provide X-ray temperatures, and thus also source temperature versus radius distributions. OB stars usually show power law differential emission measure distributions versus temperature. In models of bow shocks, we find a power law differential emission measure, a wide range of ion stages, and the bow shock flow around the clumps provides transverse velocities comparable to HWHM values. We find that the bow shock results for the line profile properties, consistent with the observations of X-ray line emission for a broad range of OB star properties. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18057 ER - TY - JOUR A1 - Nobari, Hadi A1 - Mahmoudzadeh Khalili, Sara A1 - Denche Zamorano, Angel Manuel A1 - Bowman, ‪Thomas G. A1 - Granacher, Urs T1 - Workload is associated with the occurrence of non-contact injuries in professional male soccer players: A pilot study JF - Frontiers in Psychology N2 - Injuries in professional soccer are a significant concern for teams, and they are caused amongst others by high training load. This cohort study describes the relationship between workload parameters and the occurrence of non-contact injuries, during weeks with high and low workload in professional soccer players throughout the season. Twenty-one professional soccer players aged 28.3 ± 3.9 yrs. who competed in the Iranian Persian Gulf Pro League participated in this 48-week study. The external load was monitored using global positioning system (GPS, GPSPORTS Systems Pty Ltd) and the type of injury was documented daily by the team's medical staff. Odds ratio (OR) and relative risk (RR) were calculated for non-contact injuries for high- and low-load weeks according to acute (AW), chronic (CW), acute to chronic workload ratio (ACWR), and AW variation (Δ-Acute) values. By using Poisson distribution, the interval between previous and new injuries were estimated. Overall, 12 non-contact injuries occurred during high load and 9 during low load weeks. Based on the variables ACWR and Δ-AW, there was a significantly increased risk of sustaining non-contact injuries (p < 0.05) during high-load weeks for ACWR (OR: 4.67), and Δ-AW (OR: 4.07). Finally, the expected time between injuries was significantly shorter in high load weeks for ACWR [1.25 vs. 3.33, rate ratio time (RRT)] and Δ-AW (1.33 vs. 3.45, RRT) respectively, compared to low load weeks. The risk of sustaining injuries was significantly larger during high workload weeks for ACWR, and Δ-AW compared with low workload weeks. The observed high OR in high load weeks indicate that there is a significant relationship between workload and occurrence of non-contact injuries. The predicted time to new injuries is shorter in high load weeks compared to low load weeks. Therefore, the frequency of injuries is higher during high load weeks for ACWR and Δ-AW. ACWR and Δ-AW appear to be good indicators for estimating the injury risk, and the time interval between injuries. KW - ACWR KW - external load KW - football KW - prevention KW - performance KW - injury risk Y1 - 2022 U6 - https://doi.org/10.3389/fpsyg.2022.925722 SN - 1664-1078 SP - 1 EP - 9 PB - Frontiers CY - Lausanne, Schweiz ER - TY - JOUR A1 - Draude, Claude T1 - Working with Diversity in Informatics JF - Hochschuldidaktik Informatik HDI 2021 (Commentarii informaticae didacticae) N2 - Diversity is a term that is broadly used and challenging for informatics research, development and education. Diversity concerns may relate to unequal participation, knowledge and methodology, curricula, institutional planning etc. For a lot of these areas, measures, guidelines and best practices on diversity awareness exist. A systemic, sustainable impact of diversity measures on informatics is still largely missing. In this paper I explore what working with diversity and gender concepts in informatics entails, what the main challenges are and provide thoughts for improvement. The paper includes definitions of diversity and intersectionality, reflections on the disciplinary basis of informatics and practical implications of integrating diversity in informatics research and development. In the final part, two concepts from the social sciences and the humanities, the notion of “third space”/hybridity and the notion of “feminist ethics of care”, serve as a lens to foster more sustainable ways of working with diversity in informatics. KW - Gender KW - Diversity KW - Intersectionality KW - Sociotechnical Design KW - Informatics Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-613787 SN - 978-3-86956-548-4 SN - 1868-0844 SN - 2191-1940 IS - 13 SP - 13 EP - 33 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - GEN A1 - Höhle, Barbara A1 - van de Vijver, Ruben A1 - Weissenborn, Jürgen T1 - Word processing at 19 months and its relation to language performance at 30 months : a retrospective analysis of data from German learning children N2 - Recent research has shown that the early lexical representations children establish in their second year of life already seem to be phonologically detailed enough to allow differentiation from very similar forms. In contrast to these findings children with specific language impairment show problems in discriminating phonologically similar word forms up to school age. In our study we investigated the question whether there would be differences in the processing of phonological details in normally developing and in children with low language performance in the second year of life. This was done by a retrospective study in which in the processing of phonological details was tested by a preferential looking experiment when the children were 19 months old. At the age of 30 months children were tested with a standardized German test of language comprehension and production (SETK2). The preferential looking data at 19 months revealed an opposite reaction pattern for the two groups: while the children scoring normally in the SETK2 increase their fixations of a pictured object only when it was named with the correct word, children with later low language performance did so only when presented with a phonologically slightly deviant mispronunciation. We suggest that this pattern does not point to a specific deficit in processing phonological information in these children but might be related to an instability of early phonological representations, and/or a generalized problem of information processing as compared to typically developing children. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 025 KW - Word processing KW - late talker KW - early indicators for SLI KW - processing of phonological details Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16302 ER - TY - CHAP A1 - Szeifert, T. T1 - Wind variabilities and asymmetries in Luminous Blue Variables N2 - Luminous Blue Variables show strong changes in their stellar wind on time scales of typically years to decades when they expand and contract radially at approximately constant luminosity. Micro-variability on shorter time scales and amplitudes can be observed superimposed to the larger scale radial changes. I will show long-term time series of high resolution spectra which we have collected in the past 20 years for many of the well known LBVs together with a few time series of weekly sampling (HR Car, R40, R71, R110, R127, S Dor) covering a time windows of up to a few months. Wind variability is seen on short and intermediate time scales with the line profiles changing from P Cygni to inverse P Cygni and double peeked profiles sometimes for the same star and spectral line. On longer time scales the ionisation levels for all chemical elements change drastically due to the strong change of the temperature on the stellar surface. While on the long term the characteristic radial changes may have impact on the over all mass loss rates, the variabilities and asymmetries on short and intermediate time scales may cause false estimates of the mass loss rates when confronting models with the observed line profiles Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18146 ER - TY - CHAP A1 - Weis, K. T1 - Wind relics : clumps, inhomogeneities and outflows in LBV nebulae N2 - The most massive stars are those with the shortest but most active life. One group of massive stars, the Luminous Blue Variables (LBVs), of which only a few objects are known, are in particular of interest concerning the stability of stars. They have a high mass loss rate and are close to being instable. This is even more likely as rotation becomes an important factor in stellar evolution of these stars. Through massive stellar winds and sometimes giant eruptions, LBV nebulae are formed. Various aspects in the evolution in the LBV phase lead, beside the large scale morphological and kinematical differences, to a diversity of small structures like clumps, rims, and outflows in these nebulae. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18235 ER - TY - CHAP A1 - Marchenko, S. V. T1 - Wind inhomogeneities in low-Z environment : observations N2 - We discuss the results of time-resolved spectroscopy of three presumably single Population I Wolf-Rayet stars in the Small Magellanic Cloud, where the ambient metallicity is $\sim 1/5 Z_\odot$. We were able to detect and follow numerous small-scale wind-embedded inhomogeneities in all observed stars. The general properties of the moving features, such as their velocity dispersions, emissivities and average accelerations, closely match the corresponding characteristics of small-scale inhomogeneities in the winds of Galactic Wolf-Rayet stars. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17769 ER - TY - CHAP A1 - Kraus, M. A1 - Kubát, Jiří A1 - Krtička, Jiri T1 - Wind emission of OB supergiants and the influence of clumping N2 - The influence of the wind to the total continuum of OB supergiants is discussed. For wind velocity distributions with β > 1.0, the wind can have strong influence to the total continuum emission, even at optical wavelengths. Comparing the continuum emission of clumped and unclumped winds, especially for stars with high β values, delivers flux differences of up to 30% with maximum in the near-IR. Continuum observations at these wavelengths are therefore an ideal tool to discriminate between clumped and unclumped winds of OB supergiants. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17757 ER - TY - THES A1 - Siegmund, Nicole T1 - Wind driven soil particle uptake Quantifying drivers of wind erosion across the particle size spectrum T1 - Partikelaufwirbelung durch Wind - Über die Quantifizierung von Winderosion über das ganze Partikel-Größenspektrum N2 - Among the multitude of geomorphological processes, aeolian shaping processes are of special character, Pedogenic dust is one of the most important sources of atmospheric aerosols and therefore regarded as a key player for atmospheric processes. Soil dust emissions, being complex in composition and properties, influence atmospheric processes and air quality and has impacts on other ecosystems. In this because even though their immediate impact can be considered low (exceptions exist), their constant and large-scale force makes them a powerful player in the earth system. dissertation, we unravel a novel scientific understanding of this complex system based on a holistic dataset acquired during a series of field experiments on arable land in La Pampa, Argentina. The field experiments as well as the generated data provide information about topography, various soil parameters, the atmospheric dynamics in the very lower atmosphere (4m height) as well as measurements regarding aeolian particle movement across a wide range of particle size classes between 0.2μm up to the coarse sand. The investigations focus on three topics: (a) the effects of low-scale landscape structures on aeolian transport processes of the coarse particle fraction, (b) the horizontal and vertical fluxes of the very fine particles and (c) the impact of wind gusts on particle emissions. Among other considerations presented in this thesis, it could in particular be shown, that even though the small-scale topology does have a clear impact on erosion and deposition patterns, also physical soil parameters need to be taken into account for a robust statistical modelling of the latter. Furthermore, specifically the vertical fluxes of particulate matter have different characteristics for the particle size classes. Finally, a novel statistical measure was introduced to quantify the impact of wind gusts on the particle uptake and its application on the provided data set. The aforementioned measure shows significantly increased particle concentrations during points in time defined as gust event. With its holistic approach, this thesis further contributes to the fundamental understanding of how atmosphere and pedosphere are intertwined and affect each other. N2 - Unter der Vielzahl geomorphologischer Prozesse nehmen äolische Formgebungsprozesse eine besondere Stellung ein, denn obwohl ihre unmittelbaren Auswirkungen als gering einzuschätzen sind (Ausnahmen existieren), sind sie aufgrund ihrer konstanten und großen Kraft ein mächtiger Akteur im Erdsystem. Pedogener Staub ist eine der wichtigsten Quellen atmosphärischer Aerosole und kann daher als Schlüsselfaktor für atmosphärische Prozesse angesehen werden. Bodenstaubemissionen, die in Zusammensetzung und Eigenschaften komplex sind, beeinflussen atmosphärische Prozesse und Luftqualität und haben Auswirkungen auf andere Ökosysteme. Um zum wissenschaftlichen Verständnis dieses komplexen Systems beizutragen, dokumentiert diese Arbeit eine Reihe von Veröffentlichungen, die alle auf einem ganzheitlichen Datensatz basieren, die während einer Reihe von Feldexperimenten auf Ackerland in La Pampa, Argentinien, gewonnen wurden. Die Feldexperimente sowie die generierten Daten liefern Informationen über Topographie, verschiedene Bodenparameter, die atmosphärische Dynamik in der unteren Atmosphäre (4 m Höhe) sowie Messungen zur äolischen Partikelbewegung über einen weiten Bereich von Partikelgrößenklassen zwischen 0,2μm und groben Sand. Die Untersuchungen konzentrieren sich auf drei Themen: Die Auswirkungen kleinräumiger Landschaftsstrukturen auf äolische Transportprozesse der groben Partikelfraktion, die horizontalen und vertikalen Strömungen der sehr feinen Partikel und der Einfluss von Windböen auf die Partikelemissionen. Neben anderen in dieser Arbeit vorgestellten Überlegungen konnte insbesondere gezeigt werden, dass, obwohl die kleinräumige Topologie einen deutlichen Einfluss auf Erosions- und Ablagerungsmuster hat, auch physikalische Bodenparameter für eine robuste statistische Modellierung berücksichtigt werden müssen. Darüber hinaus weisen speziell die vertikalen Feinstaubflüsse unterschiedliche Eigenschaften für die Partikelgrößenklassen auf. Schließlich wurde ein neuartiges statistisches Maß eingeführt, um den Einfluss von Windböen auf die Partikelkonzentration der Luft zu quantifizieren, und seine Anwendung auf den bereitgestellten Datensatz zeigt signifikant erhöhte Partikelkonzentrationen zu Zeitpunkten, die als Böen definiert wurden. Mit ihrem ganzheitlichen Ansatz trägt diese Arbeit weiter zum grundlegenden Verständnis bei, wie Atmosphäre und Pedosphäre miteinander verflochten sind und sich gegenseitig beeinflussen. KW - Winderosion KW - winderosion KW - PM10, PM2, PM1 KW - Horizontal flux KW - horizontaler Fluss KW - Vertical flux KW - vertikaler Fluss KW - Argentina KW - Argentinien KW - wind gusts KW - Windböen Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-574897 ER - TY - JOUR A1 - Richter, Eric A1 - Kunter, Mareike A1 - Marx, Alexandra A1 - Richter, Dirk T1 - Who participates in content-focused teacher professional development? BT - Evidence from a large scale study JF - Frontiers in education N2 - This study investigates the relationship between teacher quality and teachers’ engagement in professional development (PD) activities using data on 229 German secondary school mathematics teachers. We assessed different aspects of teacher quality (e.g. professional knowledge, instructional quality) using a variety of measures, including standardised tests of teachers’ content knowledge, to determine what characteristics are associated with high participation in PD. The results show that teachers with higher scores for teacher quality variables take part in more content-focused PD than teachers with lower scores for these variables. This suggests that teacher learning may be subject to a Matthew effect, whereby more proficient teachers benefit more from PD than less proficient teachers. KW - teacher learning KW - professional development KW - content knowledge KW - teacher quality KW - in-service training KW - Matthew effect KW - continuing education activities Y1 - 2021 U6 - https://doi.org/10.3389/feduc.2021.722169 SN - 2504-284X IS - 6 SP - 1 EP - 10 PB - Frontiers Media CY - Lausanne, Schweiz ER - TY - JOUR A1 - Raatz, Larissa A1 - Pirhofer-Walzl, Karin A1 - Müller, Marina E.H. A1 - Scherber, Christoph A1 - Joshi, Jasmin Radha T1 - Who is the culprit: Is pest infestation responsible for crop yield losses close to semi-natural habitats? JF - Ecology and Evolution N2 - Semi-natural habitats (SNHs) are becoming increasingly scarce in modern agricultural landscapes. This may reduce natural ecosystem services such as pest control with its putatively positive effect on crop production. In agreement with other studies, we recently reported wheat yield reductions at field borders which were linked to the type of SNH and the distance to the border. In this experimental landscape-wide study, we asked whether these yield losses have a biotic origin while analyzing fungal seed and fungal leaf pathogens, herbivory of cereal leaf beetles, and weed cover as hypothesized mediators between SNHs and yield. We established experimental winter wheat plots of a single variety within conventionally managed wheat fields at fixed distances either to a hedgerow or to an in-field kettle hole. For each plot, we recorded the fungal infection rate on seeds, fungal infection and herbivory rates on leaves, and weed cover. Using several generalized linear mixed-effects models as well as a structural equation model, we tested the effects of SNHs at a field scale (SNH type and distance to SNH) and at a landscape scale (percentage and diversity of SNHs within a 1000-m radius). In the dry year of 2016, we detected one putative biotic culprit: Weed cover was negatively associated with yield values at a 1-m and 5-m distance from the field border with a SNH. None of the fungal and insect pests, however, significantly affected yield, neither solely nor depending on type of or distance to a SNH. However, the pest groups themselves responded differently to SNH at the field scale and at the landscape scale. Our findings highlight that crop losses at field borders may be caused by biotic culprits; however, their negative impact seems weak and is putatively reduced by conventional farming practices. KW - arable weeds KW - cereal leaf beetle KW - fungal pathogens KW - herbivory KW - structural equation model KW - wheat Y1 - 2021 U6 - https://doi.org/10.1002/ece3.8046 SN - 1467-6435 VL - 11 SP - 13232 EP - 13246 PB - Wiley-Blackwell CY - Oxford ET - 19 ER - TY - JOUR A1 - Ladleif, Jan A1 - Weske, Mathias T1 - Which event happened first? BT - Deferred choice on blockchain using oracles JF - Frontiers in blockchain N2 - First come, first served: Critical choices between alternative actions are often made based on events external to an organization, and reacting promptly to their occurrence can be a major advantage over the competition. In Business Process Management (BPM), such deferred choices can be expressed in process models, and they are an important aspect of process engines. Blockchain-based process execution approaches are no exception to this, but are severely limited by the inherent properties of the platform: The isolated environment prevents direct access to external entities and data, and the non-continual runtime based entirely on atomic transactions impedes the monitoring and detection of events. In this paper we provide an in-depth examination of the semantics of deferred choice, and transfer them to environments such as the blockchain. We introduce and compare several oracle architectures able to satisfy certain requirements, and show that they can be implemented using state-of-the-art blockchain technology. KW - business processes KW - business process management KW - deferred choice KW - workflow patterns KW - blockchain KW - smart contracts KW - oracles KW - formal semantics Y1 - 2021 U6 - https://doi.org/10.3389/fbloc.2021.758169 SN - 2624-7852 VL - 4 SP - 1 EP - 16 PB - Frontiers in Blockchain CY - Lausanne, Schweiz ER - TY - JOUR A1 - Kitagawa, Yoshihisa ED - Ishihara, Shinichiro ED - Petrova, Svetlana ED - Schwarz, Anne T1 - When we fail to question in Japanese JF - Interdisciplinary studies on information structure : ISIS ; working papers of the SFB 632 N2 - When we pay close attention to the prosody of Wh-questions in Japanese, we discover many novel and interesting empirical puzzles that would require us to devise a much finer syntactic component of grammar. This paper addresses the issues that pose some problems to such an elaborated grammar, and offers solutions, making an appeal to the information structure and sentence processing involved in the interpretation of interrogative and focus constructions. KW - focus KW - (implicit) prosody KW - information structure KW - processing KW - Wh-question Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-24481 SN - 1866-4725 SN - 1614-4708 VL - 9 SP - 29 EP - 64 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Bellettini, Carlo A1 - Lonati, Violetta A1 - Malchiodi, Dario A1 - Monga, Mattia A1 - Morpurgo, Anna A1 - Torelli, Mauro T1 - What you see is what you have in mind BT - constructing mental models for formatted text processing JF - Commentarii informaticae didacticae : (CID) N2 - In this paper we report on our experiments in teaching computer science concepts with a mix of tangible and abstract object manipulations. The goal we set ourselves was to let pupils discover the challenges one has to meet to automatically manipulate formatted text. We worked with a group of 25 secondary school pupils (9-10th grade), and they were actually able to “invent” the concept of mark-up language. From this experiment we distilled a set of activities which will be replicated in other classes (6th grade) under the guidance of maths teachers. Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-64612 SN - 1868-0844 SN - 2191-1940 IS - 6 SP - 139 EP - 147 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - RPRT A1 - Bachelet, Marion A1 - Kalkuhl, Matthias A1 - Koch, Nicolas T1 - What if working from home will stick? BT - Distributional and climate impacts for Germany T2 - CEPA Discussion Papers N2 - The COVID-19 pandemic created the largest experiment in working from home. We study how persistent telework may change energy and transport consumption and costs in Germany to assess the distributional and environmental implications when working from home will stick. Based on data from the German Microcensus and available classifications of working-from-home feasibility for different occupations, we calculate the change in energy consumption and travel to work when 15% of employees work full time from home. Our findings suggest that telework translates into an annual increase in heating energy expenditure of 110 euros per worker and a decrease in transport expenditure of 840 euros per worker. All income groups would gain from telework but high-income workers gain twice as much as low-income workers. The value of time saving is between 1.3 and 6 times greater than the savings from reduced travel costs and almost 9 times higher for high-income workers than low-income workers. The direct effects on CO₂ emissions due to reduced car commuting amount to 4.5 millions tons of CO₂, representing around 3 percent of carbon emissions in the transport sector. T3 - CEPA Discussion Papers - 41 KW - commuting KW - home office KW - COVID-19 KW - energy expenditure KW - carbon emissions Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-532384 SN - 2628-653X IS - 41 ER - TY - CHAP A1 - Zhou, Neng-Fa T1 - What I have learned from all these solver competitions N2 - In this talk, I would like to share my experiences gained from participating in four CSP solver competitions and the second ASP solver competition. In particular, I’ll talk about how various programming techniques can make huge differences in solving some of the benchmark problems used in the competitions. These techniques include global constraints, table constraints, and problem-specific propagators and labeling strategies for selecting variables and values. I’ll present these techniques with experimental results from B-Prolog and other CLP(FD) systems. Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-41431 ER - TY - JOUR A1 - Scheffler, Christiane A1 - Hermanussen, Michael T1 - What does stunting tell us? JF - Human biology and public health N2 - Stunting is commonly linked with undernutrition. Yet, already after World War I, German pediatricians questioned this link and stated that no association exists between nutrition and height. Recent analyses within different populations of Low- and middle-income countries with high rates of stunted children failed to support the assumption that stunted children have a low BMI and skinfold sickness as signs of severe caloric deficiency. So, stunting is not a synonym of malnutrition. Parental education level has a positive influence on body height in stunted populations, e.g., in India and in Indonesia. Socially disadvantaged children tend to be shorter and lighter than children from affluent families. Humans are social mammals; they regulate growth similar to other social mammals. Also in humans, body height is strongly associated with the position within the social hierarchy, reflecting the personal and group-specific social, economic, political, and emotional environment. These non-nutritional impact factors on growth are summarized by the concept of SEPE (Social-Economic-Political-Emotional) factors. SEPE reflects on prestige, dominance-subordination, social identity, and ego motivation of individuals and social groups. KW - SEPE Factors KW - physical fitness KW - height in history KW - malnutrition Y1 - 2023 U6 - https://doi.org/10.52905/hbph2022.3.36 SN - 2748-9957 VL - 2022 IS - 3 SP - 1 EP - 15 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - CHAP A1 - Kholtygin, A. F. T1 - Wavelets for looking for clumping in the wind of OB stars N2 - Clumping in hot-star winds : proceedings of an international workshop held in Potsdam, Germany, 18. - 22. June 2007 Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17796 ER - TY - JOUR A1 - Meyer, Roland T1 - VP-fronting in Czech and Polish BT - a case study in corpus-oriented grammar research JF - Interdisciplinary studies on information structure : ISIS ; working papers of the SFB 632 N2 - Fronting of an infinite VP across a finite main verb-akin to German "VP-topicalization"-can be found also in Czech and Polish. The paper discusses evidence from large corpora for this process and some of its properties, both syntactic and information-structural. Based on this case, criteria for more user-friedly searching and retrieval of corpus data in syntactic research are being developed. Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-8662 SN - 1866-4725 SN - 1614-4708 IS - 2 SP - 87 EP - 115 ER - TY - THES A1 - Ruch, Joël T1 - Volcano deformation analysis in the Lazufre area (central Andes) using geodetic and geological observations T1 - Vulkan Deformationsanalyse im Bereich Lazufre (Zentral-Anden) mit geodätischen und geologischen Beobachtungen N2 - Large-scale volcanic deformation recently detected by radar interferometry (InSAR) provides new information and thus new scientific challenges for understanding volcano-tectonic activity and magmatic systems. The destabilization of such a system at depth noticeably affects the surrounding environment through magma injection, ground displacement and volcanic eruptions. To determine the spatiotemporal evolution of the Lazufre volcanic area located in the central Andes, we combined short-term ground displacement acquired by InSAR with long-term geological observations. Ground displacement was first detected using InSAR in 1997. By 2008, this displacement affected 1800 km2 of the surface, an area comparable in size to the deformation observed at caldera systems. The original displacement was followed in 2000 by a second, small-scale, neighbouring deformation located on the Lastarria volcano. We performed a detailed analysis of the volcanic structures at Lazufre and found relationships with the volcano deformations observed with InSAR. We infer that these observations are both likely to be the surface expression of a long-lived magmatic system evolving at depth. It is not yet clear whether Lazufre may trigger larger unrest or volcanic eruptions; however, the second deformation detected at Lastarria and the clear increase of the large-scale deformation rate make this an area of particular interest for closer continuous monitoring. N2 - Vulkanische Deformationen in großem Maßstab, die mittels InSAR gemessen wurden, liefern neue Informationen und dadurch einen neuen Blickwinkel auf vulkan-tektonische Aktivitäten und das Verständnis von langlebigen, magmatischen Systemen. Die Destabilisierung eines solchen Systems in der Tiefe beeinflusst dauerhaft die Oberfläche durch Versatz des Bodens, magmatische Einflüsse und vulkanische Unruhen. Mit der Kombination aus kleinräumigem Bodenversatz gemessen mittels InSAR, numerischer Modellierung und langfristigen geologischen Beobachtungen, analysieren wir die Gegend um den Vulkan Lazufre in den Zentralanden, um die raumzeitliche Entwicklung der Region zu bestimmen. Bodenversatz wurde hierbei im Jahr 1997 mittels Radar-Interferrometrie (InSAR) gemessen, was eine Fläche von 1800 km² ausmacht, vergleichbar mit der Größe der Deformation des Kraters. Im Jahr 2000 wurde zusätzlich eine kleinräumige Deformation am Nachbarvulkan Lastarria entdeckt. Wir sehen räumliche als auch zeitliche Verbindungen zwischen der Deformation des Vulkans und vulkanischen Strukturen innerhalb der betroffenen Gegend. Wir folgern daraus, dass diese Beobachtungen der Ausdruck eines langlebigen, magmatischen Systems in der Tiefe an der Oberfläche sind. Es ist noch nicht klar, ob Lazufre größere vulkanische Unruhen, wie zum Beispiel Eruptionen auslösen könnte, aber die Deformation am Vulkan Lastarria und ein Anstieg der großräumigen Deformationsrate, machen diese Region interessant für eine zukünftige, kontinuierliche Überwachung. KW - Vulkan Verformung KW - InSAR KW - zentralen Anden KW - Spannungsfeld KW - volcano deformation KW - InSAR KW - central Andes KW - stress field Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-47361 ER - TY - JOUR A1 - Hecker, Pascal A1 - Steckhan, Nico A1 - Eyben, Florian A1 - Schuller, Björn Wolfgang A1 - Arnrich, Bert T1 - Voice Analysis for Neurological Disorder Recognition – A Systematic Review and Perspective on Emerging Trends JF - Frontiers in Digital Health N2 - Quantifying neurological disorders from voice is a rapidly growing field of research and holds promise for unobtrusive and large-scale disorder monitoring. The data recording setup and data analysis pipelines are both crucial aspects to effectively obtain relevant information from participants. Therefore, we performed a systematic review to provide a high-level overview of practices across various neurological disorders and highlight emerging trends. PRISMA-based literature searches were conducted through PubMed, Web of Science, and IEEE Xplore to identify publications in which original (i.e., newly recorded) datasets were collected. Disorders of interest were psychiatric as well as neurodegenerative disorders, such as bipolar disorder, depression, and stress, as well as amyotrophic lateral sclerosis amyotrophic lateral sclerosis, Alzheimer's, and Parkinson's disease, and speech impairments (aphasia, dysarthria, and dysphonia). Of the 43 retrieved studies, Parkinson's disease is represented most prominently with 19 discovered datasets. Free speech and read speech tasks are most commonly used across disorders. Besides popular feature extraction toolkits, many studies utilise custom-built feature sets. Correlations of acoustic features with psychiatric and neurodegenerative disorders are presented. In terms of analysis, statistical analysis for significance of individual features is commonly used, as well as predictive modeling approaches, especially with support vector machines and a small number of artificial neural networks. An emerging trend and recommendation for future studies is to collect data in everyday life to facilitate longitudinal data collection and to capture the behavior of participants more naturally. Another emerging trend is to record additional modalities to voice, which can potentially increase analytical performance. KW - neurological disorders KW - voice KW - speech KW - everyday life KW - multiple modalities KW - machine learning KW - disorder recognition Y1 - 2022 U6 - https://doi.org/10.3389/fdgth.2022.842301 SN - 2673-253X PB - Frontiers Media SA CY - Lausanne, Schweiz ER - TY - JOUR A1 - Pawassar, Christian Matthias A1 - Tiberius, Victor T1 - Virtual reality in health care BT - Bibliometric analysis JF - JMIR Serious Games N2 - Background: Research into the application of virtual reality technology in the health care sector has rapidly increased, resulting in a large body of research that is difficult to keep up with. Objective: We will provide an overview of the annual publication numbers in this field and the most productive and influential countries, journals, and authors, as well as the most used, most co-occurring, and most recent keywords. Methods: Based on a data set of 356 publications and 20,363 citations derived from Web of Science, we conducted a bibliometric analysis using BibExcel, HistCite, and VOSviewer. Results: The strongest growth in publications occurred in 2020, accounting for 29.49% of all publications so far. The most productive countries are the United States, the United Kingdom, and Spain; the most influential countries are the United States, Canada, and the United Kingdom. The most productive journals are the Journal of Medical Internet Research (JMIR), JMIR Serious Games, and the Games for Health Journal; the most influential journals are Patient Education and Counselling, Medical Education, and Quality of Life Research. The most productive authors are Riva, del Piccolo, and Schwebel; the most influential authors are Finset, del Piccolo, and Eide. The most frequently occurring keywords other than “virtual” and “reality” are “training,” “trial,” and “patients.” The most relevant research themes are communication, education, and novel treatments; the most recent research trends are fitness and exergames. Conclusions: The analysis shows that the field has left its infant state and its specialization is advancing, with a clear focus on patient usability. KW - virtual reality KW - healthcare KW - bibliometric analysis KW - literature review KW - citation analysis KW - VR KW - usability KW - review KW - health care Y1 - 2021 U6 - https://doi.org/10.2196/32721 SN - 2291-9279 VL - 9 SP - 1 EP - 19 PB - JMIR Publications CY - Toronto, Kanada ET - 4 ER - TY - JOUR A1 - Scheffler, Christiane A1 - Nguyen, Thi Hong A1 - Hermanussen, Michael T1 - Vietnamese migrants are as tall as they want to be JF - Human biology and public health N2 - Background: Members of the same social group tent to have the same body height. Migrants tend to adjust in height to their host communities. Objectives: Social-Economic-Political-Emotional (SEPE) factors influence growth. We hypothesized that Vietnamese young adult migrants in Germany (1) are taller than their parents, (2) are as tall as their German peers, and (3) are as tall as predicted by height expectation at age 13 years. Sample: The study was conducted in 30 male and 54 female Vietnamese migrants (mean age 26.23 years. SD=4.96) in Germany in 2020. Methods: Information on age, sex, body height, school and education, job, height and ethnicity of best friend, migration history and cultural identification, parental height and education, and recalled information on their personal height expectations at age 13 years were obtained by questionnaire. The data were analyzed by St. Nicolas House Analysis (SNHA) and multiple regression. Results: Vietnamese young adults are taller than their parents (females 3.85cm, males 7.44cm), but do not fully attain height of their German peers. The body height is positively associated with the height of best friend (p < 0.001), the height expectation at age 13 year (p < 0.001), and father’s height (p=0.001). Conclusion: Body height of Vietnamese migrants in Germany reflects competitive growth and strategic growth adjustments. The magnitude of this intergenerational trend supports the concept that human growth depends on SEPE factors. KW - body height KW - regulation of growth KW - migrants KW - Social-Economic-Political-Emotional (SEPE) factors Y1 - 2021 U6 - https://doi.org/10.52905/hbph.v2.12 SN - 2748-9957 IS - 2 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - CHAP A1 - Reimer, O. A1 - Aharonian, Felix A. A1 - Hinton, J. A1 - Hofmann, W. A1 - Hoppe, S. A1 - Raue, M. A1 - Reimer, A. T1 - VHE gamma-rays from Westerlund 2 and implications for the inferred energetics N2 - The H.E.S.S. collaboration recently reported the discovery of VHE γ-ray emission coincident with the young stellar cluster Westerlund 2. This system is known to host a population of hot, massive stars, and, most particularly, the WR binary WR 20a. Particle acceleration to TeV energies in Westerlund 2 can be accomplished in several alternative scenarios, therefore we only discuss energetic constraints based on the total available kinetic energy in the system, the actual mass loss rates of respective cluster members, and implied gamma-ray production from processes such as inverse Compton scattering or neutral pion decay. From the inferred gammaray luminosity of the order of 1035erg/s, implications for the efficiency of converting available kinetic energy into non-thermal radiation associated with stellar winds in the Westerlund 2 cluster are discussed under consideration of either the presence or absence of wind clumping. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18172 ER - TY - THES A1 - Giuri, Chiara T1 - VERITAS Dark Matter search in dwarf spheroidal galaxies: an extended analysis T1 - VERITAS-Suche nach dunkler Materie in sphäroidischen Zwerggalaxien: eine erweiterte Analyse” N2 - In the last century, several astronomical measurements have supported that a significant percentage (about 22%) of the total mass of the Universe, on galactic and extragalactic scales, is composed of a mysterious ”dark” matter (DM). DM does not interact with the electromagnetic force; in other words it does not reflect, absorb or emit light. It is possible that DM particles are weakly interacting massive particles (WIMPs) that can annihilate (or decay) into Standard Model (SM) particles, and modern very- high-energy (VHE; > 100 GeV) instruments such as imaging atmospheric Cherenkov telescopes (IACTs) can play an important role in constraining the main properties of such DM particles, by detecting these products. One of the most privileged targets where to look for DM signal are dwarf spheroidal galaxies (dSphs), as they are expected to be high DM-dominated objects with a clean, gas-free environment. Some dSphs could be considered as extended sources, considering the angular resolution of IACTs; their angu- lar resolution is adequate to detect extended emission from dSphs. For this reason, we performed an extended-source analysis, by taking into account in the unbinned maximum likelihood estimation both the energy and the angular extension dependency of observed events. The goal was to set more constrained upper limits on the velocity-averaged cross-section annihilation of WIMPs with VERITAS data. VERITAS is an array of four IACTs, able to detect γ-ray photons ranging between 100 GeV and 30 TeV. The results of this extended analysis were compared against the traditional spectral analysis. We found that a 2D analysis may lead to more constrained results, depending on the DM mass, channel, and source. Moreover, in this thesis, the results of a multi-instrument project are presented too. Its goal was to combine already published 20 dSphs data from five different experiments, such as Fermi-LAT, MAGIC, H.E.S.S., VERITAS and HAWC, in order to set upper limits on the WIMP annihilation cross-section in the widest mass range ever reported. N2 - Im letzten Jahrhundert haben verschiedene mehrere astronomische Messungen gezeigt, dass ein erheblicher Prozentsatz (etwa 22 %) der Gesamtmasse des Universums auf galaktischer und extragalaktischer Ebene aus einer geheimnisvollen ”dunklen” Materie (DM) besteht. DM interagiert nicht mit der elektromagnetischen Kraft und reflektiert, absorbiert oder emittiert daher kein Licht. Es ist möglich, dass es sich bei DM-Teilchen um schwach wechselwirkende massive Teilchen (engl. weakly interacting massive particles, WIMPs) handelt, die in Teilchen des Standardmodells (SM) annihilieren (oder zerfallen) können. Indem sie diese Produkte nachweisen, können moderne Detektoren für sehr hoch energetische (engl. very-high-energy, VHE; 100 GeV) Gammastrahlung, wie zum Beispiel bildgebende atmosphärische Cherenkov-Teleskope (engl. imaging atmospheric Cherenkov telescopes, IACTs), eine wichtige Rolle bei der Bestimmung der Haupteigenschaften solcher DM-Teilchen spielen. Eines der am besten geeignetsten Ziele für die Suche nach DM-Signalen sind sphäroidische Zwerggalaxien (engl. dwarf spheroidal galaxies, dSphs), da diese stark DM-dominierte Objekte mit einer gasfreien Umgebung sind. Die Winkelauflösung von IACTs ist ausreichend, um ausgedehnte Emission von dSphs zu entdecken. Aus diesem Grund haben wir eine Analyse dieser Quellen durchgeführt, indem wir in der unbinned Maximum-Likelihood-Schätzung sowohl die Energie als auch die Abhängigkeit der Winkelausdehnung der beobachteten Gammastrahlung berücksichtigt haben. Das Ziel war es, mit Hilfe der VERITAS-Daten genauere Obergrenzen für den geschwindigkeitsgemittelten Annihilationsquerschnitt von WIMPs zu bestimmen. VERITAS ist eine Anordnung von vier IACTs, die Gammastrahlen im Bereich von 100 GeV bis 30 TeV detektieren können. Die Ergebnisse dieser erweiterten Analyse wurden mit der traditionellen Spektralanalyse verglichen. Es zeigte sich, dass je nach DM-Masse, Kanal und Quelle eine 2D-Analyse zu aussagekräftigeren Ergebnissen führen kann. Darüber hinaus werden in dieser Arbeit auch die Ergebnisse eines Multi-Instrumenten-Projekts vorgestellt. Das Ziel war es, die bereits veröffentlichte 20 dSphs-Datensätze von Fermi-LAT, MAGIC, H.E.S.S., VERITAS und HAWC zu kombinieren, um obere Grenzwerte für den WIMP-Annihilationsquerschnitt im breitesten jemals veröffentlichten Massenbereich zu bestimmen. KW - Dark Matter KW - data analysis KW - Cherenkov telescopes KW - dwarf spheroidal galaxies KW - Dunkle Materie KW - Datenanalyse KW - Cherenkov-Teleskope KW - sphäroidische Zwerggalaxien Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-575869 ER - TY - CHAP A1 - Bergmann, Kirsten A1 - Kopp, Stefan T1 - Verbal or visual? : How information is distributed across speech and gesture in spatial dialog N2 - In spatial dialog like in direction giving humans make frequent use of speechaccompanying gestures. Some gestures convey largely the same information as speech while others complement speech. This paper reports a study on how speakers distribute meaning across speech and gesture, and depending on what factors. Utterance meaning and the wider dialog context were tested by statistically analyzing a corpus of direction-giving dialogs. Problems of speech production (as indicated by discourse markers and disfluencies), the communicative goals, and the information status were found to be influential, while feedback signals by the addressee do not have any influence. Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10375 ER - TY - JOUR A1 - Kiemel, Katrin A1 - Gurke, Marie A1 - Paraskevopoulou, Sofia A1 - Havenstein, Katja A1 - Weithoff, Guntram A1 - Tiedemann, Ralph T1 - Variation in heat shock protein 40 kDa relates to divergence in thermotolerance among cryptic rotifer species JF - Scientific Reports N2 - Genetic divergence and the frequency of hybridization are central for defining species delimitations, especially among cryptic species where morphological differences are merely absent. Rotifers are known for their high cryptic diversity and therefore are ideal model organisms to investigate such patterns. Here, we used the recently resolved Brachionus calyciflorus species complex to investigate whether previously observed between species differences in thermotolerance and gene expression are also reflected in their genomic footprint. We identified a Heat Shock Protein gene (HSP 40 kDa) which exhibits cross species pronounced sequence variation. This gene exhibits species-specific fixed sites, alleles, and sites putatively under positive selection. These sites are located in protein binding regions involved in chaperoning and may therefore reflect adaptive diversification. By comparing three genetic markers (ITS, COI, HSP 40 kDa), we revealed hybridization events between the cryptic species. The low frequency of introgressive haplotypes/alleles suggest a tight, but not fully impermeable boundary between the cryptic species. Y1 - 2022 U6 - https://doi.org/10.1038/s41598-022-27137-3 SN - 2045-2322 VL - 12 PB - Springer Nature CY - London ER - TY - JOUR A1 - Schjeide, Brit-Maren A1 - Schenke, Maren A1 - Seeger, Bettina A1 - Püschel, Gerhard T1 - Validation of a novel double control quantitative copy number PCR method to quantify off-target transgene integration after CRISPR-induced DNA modification JF - Methods and protocols : M&Ps N2 - In order to improve a recently established cell-based assay to assess the potency of botulinum neurotoxin, neuroblastoma-derived SiMa cells and induced pluripotent stem-cells (iPSC) were modified to incorporate the coding sequence of a reporter luciferase into a genetic safe harbor utilizing CRISPR/Cas9. A novel method, the double-control quantitative copy number PCR (dc-qcnPCR), was developed to detect off-target integrations of donor DNA. The donor DNA insertion success rate and targeted insertion success rate were analyzed in clones of each cell type. The dc-qcnPCR reliably quantified the copy number in both cell lines. The probability of incorrect donor DNA integration was significantly increased in SiMa cells in comparison to the iPSCs. This can possibly be explained by the lower bundled relative gene expression of a number of double-strand repair genes (BRCA1, DNA2, EXO1, MCPH1, MRE11, and RAD51) in SiMa clones than in iPSC clones. The dc-qcnPCR offers an efficient and cost-effective method to detect off-target CRISPR/Cas9-induced donor DNA integrations. KW - CRISPR editing validation KW - copy number analyses KW - homology-directed repair KW - homologous recombination deficiency Y1 - 2022 U6 - https://doi.org/10.3390/mps5030043 SN - 2409-9279 VL - 5 IS - 3 SP - 1 EP - 14 PB - MDPI CY - Basel, Schweiz ER - TY - JOUR A1 - Berry, Carol A1 - Kusterer, Peter T1 - Using Teachers’ TryScience to support educators and improve teaching JF - Commentarii informaticae didacticae : (CID) N2 - The challenge is providing teachers with the resources they need to strengthen their instructions and better prepare students for the jobs of the 21st Century. Technology can help meet the challenge. Teachers’ Tryscience is a noncommercial offer, developed by the New York Hall of Science, TeachEngineering, the National Board for Professional Teaching Standards and IBM Citizenship to provide teachers with such resources. The workshop provides deeper insight into this tool and discussion of how to support teaching of informatics in schools. KW - science KW - teacher KW - collaboration KW - teaching material KW - instruction KW - lesson KW - social networking Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-64665 SN - 1868-0844 SN - 2191-1940 IS - 6 SP - 161 EP - 162 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - CHAP A1 - Doktor, Daniel A1 - Badeck, Franz-Werner A1 - Bondeau, Alberte A1 - Koslowsky, Dirk A1 - Schaber, Jörg A1 - McAllister, Murdock T1 - Using satellite imagery and ground observations to quantify the effect of intra-annually changing temperature patterns on spring time phenology N2 - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006 Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7244 N1 - [Poster] ER - TY - THES A1 - Schmitz, Seán T1 - Using low-cost sensors to gather high resolution measurements of air quality in urban environments and inform mobility policy N2 - Air pollution has been a persistent global problem in the past several hundred years. While some industrialized nations have shown improvements in their air quality through stricter regulation, others have experienced declines as they rapidly industrialize. The WHO’s 2021 update of their recommended air pollution limit values reflects the substantial impacts on human health of pollutants such as NO2 and O3, as recent epidemiological evidence suggests substantial long-term health impacts of air pollution even at low concentrations. Alongside developments in our understanding of air pollution's health impacts, the new technology of low-cost sensors (LCS) has been taken up by both academia and industry as a new method for measuring air pollution. Due primarily to their lower cost and smaller size, they can be used in a variety of different applications, including in the development of higher resolution measurement networks, in source identification, and in measurements of air pollution exposure. While significant efforts have been made to accurately calibrate LCS with reference instrumentation and various statistical models, accuracy and precision remain limited by variable sensor sensitivity. Furthermore, standard procedures for calibration still do not exist and most proprietary calibration algorithms are black-box, inaccessible to the public. This work seeks to expand the knowledge base on LCS in several different ways: 1) by developing an open-source calibration methodology; 2) by deploying LCS at high spatial resolution in urban environments to test their capability in measuring microscale changes in urban air pollution; 3) by connecting LCS deployments with the implementation of local mobility policies to provide policy advice on resultant changes in air quality. In a first step, it was found that LCS can be consistently calibrated with good performance against reference instrumentation using seven general steps: 1) assessing raw data distribution, 2) cleaning data, 3) flagging data, 4) model selection and tuning, 5) model validation, 6) exporting final predictions, and 7) calculating associated uncertainty. By emphasizing the need for consistent reporting of details at each step, most crucially on model selection, validation, and performance, this work pushed forward with the effort towards standardization of calibration methodologies. In addition, with the open-source publication of code and data for the seven-step methodology, advances were made towards reforming the largely black-box nature of LCS calibrations. With a transparent and reliable calibration methodology established, LCS were then deployed in various street canyons between 2017 and 2020. Using two types of LCS, metal oxide (MOS) and electrochemical (EC), their performance in capturing expected patterns of urban NO2 and O3 pollution was evaluated. Results showed that calibrated concentrations from MOS and EC sensors matched general diurnal patterns in NO2 and O3 pollution measured using reference instruments. While MOS proved to be unreliable for discerning differences among measured locations within the urban environment, the concentrations measured with calibrated EC sensors matched expectations from modelling studies on NO2 and O3 pollution distribution in street canyons. As such, it was concluded that LCS are appropriate for measuring urban air quality, including for assisting urban-scale air pollution model development, and can reveal new insights into air pollution in urban environments. To achieve the last goal of this work, two measurement campaigns were conducted in connection with the implementation of three mobility policies in Berlin. The first involved the construction of a pop-up bike lane on Kottbusser Damm in response to the COVID-19 pandemic, the second surrounded the temporary implementation of a community space on Böckhstrasse, and the last was focused on the closure of a portion of Friedrichstrasse to all motorized traffic. In all cases, measurements of NO2 were collected before and after the measure was implemented to assess changes in air quality resultant from these policies. Results from the Kottbusser Damm experiment showed that the bike-lane reduced NO2 concentrations that cyclists were exposed to by 22 ± 19%. On Friedrichstrasse, the street closure reduced NO2 concentrations to the level of the urban background without worsening the air quality on side streets. These valuable results were communicated swiftly to partners in the city administration responsible for evaluating the policies’ success and future, highlighting the ability of LCS to provide policy-relevant results. As a new technology, much is still to be learned about LCS and their value to academic research in the atmospheric sciences. Nevertheless, this work has advanced the state of the art in several ways. First, it contributed a novel open-source calibration methodology that can be used by a LCS end-users for various air pollutants. Second, it strengthened the evidence base on the reliability of LCS for measuring urban air quality, finding through novel deployments in street canyons that LCS can be used at high spatial resolution to understand microscale air pollution dynamics. Last, it is the first of its kind to connect LCS measurements directly with mobility policies to understand their influences on local air quality, resulting in policy-relevant findings valuable for decisionmakers. It serves as an example of the potential for LCS to expand our understanding of air pollution at various scales, as well as their ability to serve as valuable tools in transdisciplinary research. N2 - Luftverschmutzung ist seit hundert Jahren ein anhaltendes globales Problem. Während sich die Luftqualität in einigen Industrieländern durch strengere Vorschriften verbessert hat, hat sie sich in anderen Ländern im Zuge der schnell fortschreitenden Industrialisierung verschlechtert. Die Aktualisierung der von der WHO für das Jahr 2021 empfohlenen Grenzwerte für die Luftverschmutzung spiegelt die erheblichen Aus-wirkungen von Schadstoffen wie Stickstoffdioxid (NO2) und Ozon (O3) auf die menschliche Gesundheit wider, da neuere epidemiologische Erkenntnisse darauf hindeuten, dass Luft-verschmutzung selbst bei niedrigen Konzentrationen erhebliche langfristige gesundheitliche Auswirkungen hat. Parallel zu den Entwicklungen in unserem Verständnis der gesundheitlichen Auswirkungen von Luftverschmutzung wurde die neue Technologie der Low-Cost-Sensoren (LCS) sowohl von der Wissenschaft als auch von der Industrie als neue Methode zur Messung der Luftverschmutzung aufgegriffen. Vor allem aufgrund ihrer geringeren Kosten und kleineren Größe können sie in einer Vielzahl von Anwendungen eingesetzt werden, u. a. bei der Entwicklung von Messnetzen mit höherer räumlicher Auf-lösung, bei der Identifizierung von Quellen und bei der Messung der Luftverschmutzung. Es wurden zwar erhebliche Anstrengungen unternommen, um LCS mit Hilfe von Referenzinstrumenten und verschiedenen statistischen Modellen genau zu kalibrieren, aber die Genauigkeit und Präzision bleiben durch die variable Sensorempfindlichkeit begrenzt. Darüber hinaus gibt es immer noch keine Standardverfahren für die Kalibrierung, und die meisten proprietären Kalibrierungsalgorithmen sind Blackboxen, die für die Öffentlichkeit nicht zugänglich sind. Mit dieser Arbeit soll die Wissensbasis über LCS auf verschiedene Weise erweitert werden: 1) durch die Entwicklung einer Open-Source-Kalibrierungsmethodik; 2) durch den Einsatz von LCS mit hoher räumlicher Auflösung in städtischen Umgebungen, um ihre Fähigkeit zur Messung kleinräumlicher Veränderungen der städtischen Luftverschmutzung zu testen; 3) durch die Verknüpfung von LCS-Einsätzen mit der Umsetzung lokaler Verkehrsmaßnahmen, um politische Empfehlungen zu den daraus resultierenden Veränderungen der Luftqualität geben zu können. In einem ersten Schritt wurde festgestellt, dass LCS mit Hilfe von sieben allgemeinen Schritten konsistent und mit guter Leistung gegenüber Referenzinstrumenten kalibriert werden können: 1) Bewertung der Rohdatenverteilung, 2) Datenbereinigung, 3) Kenn-zeichnung von Daten, 4) Modellauswahl und -abstimmung, 5) Modellvalidierung, 6) Export der endgültigen Vorhersagen und 7) Berechnung der damit verbundenen Unsicherheit. Durch die Betonung der Notwendigkeit einer konsistenten Berichterstattung über Details bei jedem Schritt, insbesondere bei der Modellauswahl, -validierung und -leistung, hat diese Arbeit die Bemühungen um eine Standardisierung der Kalibrierungs-methoden vorangetrieben. Darüber hinaus wurden mit der Open-Source-Veröffentlichung von Code und Daten für die siebenstufige Methodik Fortschritte bei der Reformierung der weitgehenden Blackbox-Natur von LCS-Kalibrierungen erzielt. Nach der Einführung einer transparenten und zuverlässigen Kalibrierungsmethode wurden die LCS zwischen 2017 und 2020 an verschiedenen Straßen eingesetzt. Unter Ver-wendung von zwei Arten von LCS, Metalloxid (MOS) und elektrochemisch (EC), wurde ihre Leistung bei der Erfassung der erwarteten Muster der NO2- und O3-Belastung in Städten bewertet. Die Ergebnisse zeigten, dass die kalibrierten Konzentrationen der MOS- und EC-Sensoren mit den allgemeinen Tagesmustern der NO2- und O3-Belastung überein-stimmten, die mit Referenzgeräten gemessen wurden. Während sich MOS als unzuverlässig erwies, wenn es darum ging, Unterschiede zwischen den gemessenen Orten inner-halb der städtischen Umgebung zu erkennen, entsprachen die mit kalibrierten EC-Sensoren gemessenen Konzentrationen den Erwartungen aus Modellierungsstudien zur Verteilung der NO2- und O3-Belastung in Straßenschluchten. Daraus wurde der Schluss gezogen, dass LCS für die Messung der Luftqualität in Städten geeignet sind, auch zur Unterstützung der Entwicklung von Luftverschmutzungsmodellen auf städtischer Ebene, und dass sie neue Erkenntnisse über die Luftverschmutzung in städtischen Umgebungen liefern können. Um das letzte Ziel dieser Arbeit zu erreichen, wurden zwei Messkampagnen im Zusammenhang mit der Umsetzung von drei verkehrspolitischen Maßnahmen in Berlin durchgeführt. Bei der ersten handelte es sich um den Bau einer Pop-up-Radweg auf dem Kottbusser Damm als Reaktion auf die COVID-19-Pandemie, bei der zweiten um die vorübergehende Einrichtung eines Gemeinschaftsraums in der Böckhstraße und bei der letzten um die Sperrung eines Teils der Friedrichstraße für den gesamten motorisierten Verkehr. In allen Fällen wurden NO2-Messungen vor und nach der Durchführung der Maßnahme durchgeführt, um die Veränderungen der Luftqualität infolge dieser Maßnahmen zu bewerten. Die Ergebnisse des Experiments am Kottbusser Damm zeigten, dass die NO2-Konzentrationen, denen die Radfahrer ausgesetzt waren, durch den Radweg um 22 ± 19 % gesenkt wurden. In der Friedrichstraße sank die NO2-Konzentration durch die Straßensperrung auf das Niveau des städtischen Hintergrunds, ohne dass sich die Luft-qualität in den Seitenstraßen verschlechterte. Diese wertvollen Ergebnisse wurden den verantwortlichen Ansprechpersonen in der Stadtverwaltung, die für die Bewertung des Erfolgs und der Zukunft der Maßnahmen verantwortlich sind, schnell mitgeteilt, was die Fähigkeit von LCS unterstreicht, politisch relevante Ergebnisse zu liefern. Da es sich um eine neue Technologie handelt, muss noch viel über LCS und ihren Wert für die akademische Forschung im Bereich der Atmosphärenwissenschaften gelernt werden. Dennoch hat diese Arbeit den Stand der Technik in mehrfacher Hinsicht verbessert. Erstens wurde eine neuartige Open-Source-Kalibrierungsmethode entwickelt, die von LCS-Anwender*innen für verschiedene Luftschadstoffe verwendet werden kann. Zweitens wurde die Beweisgrundlage für die Zuverlässigkeit von LCS zur Messung der Luftqualität in Städten gestärkt, indem durch neuartige Einsätze in Straßenschluchten festgestellt wurde, dass LCS mit hoher räumlicher Auflösung zum Verständnis der Dynamik der Luftverschmutzung auf kleinräumlicher Ebene eingesetzt werden kann. Schließlich ist es die erste Studie dieser Art, die LCS-Messungen direkt mit verkehrspolitischen Maßnahmen verknüpft, um deren Einfluss auf die lokale Luftqualität zu verstehen, was zu politisch relevanten Erkenntnissen führt, die für Entscheidungsträger*innen wertvoll sind. Die Studie ist ein Beispiel für das Potenzial von LCS, unser Verständnis von Luftverschmutzung in verschiedenen Maßstäben zu erweitern, sowie für ihre Fähigkeit, als wert-volle Werkzeuge in der transdisziplinären Forschung zu dienen. T2 - Verwendung kostengünstiger Sensoren zur Erfassung hochauflösender Messungen der Luftqualität in städtischen Umgebungen und zur Information über die Mobilitätspolitik KW - air pollution KW - urban KW - low-cost sensor KW - transdisciplinary KW - sustainability KW - mobility KW - policy KW - Luftverschmutzung KW - Mobilität KW - Politik KW - Nachhaltigkeit KW - Transdisziplinarität KW - Städte Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-601053 ER - TY - CHAP A1 - Romero, G. E. A1 - Owocki, S. P. A1 - Araudo, A. T. A1 - Townsend, R. H. D. A1 - Benaglia, P. T1 - Using gamma-rays to probe the clumped structure of stellar winds N2 - Gamma-rays can be produced by the interaction of a relativistic jet and the matter of the stellar wind in the subclass of massive X-ray binaries known as “microquasars”. The relativistic jet is ejected from the surroundings of the compact object and interacts with cold protons from the stellar wind, producing pions that then quickly decay into gamma-rays. Since the resulting gamma-ray emissivity depends on the target density, the detection of rapid variability in microquasars with GLAST and the new generation of Cherenkov imaging arrays could be used to probe the clumped structure of the stellar wind. In particular, we show here that the relative fluctuation in gamma rays may scale with the square root of the ratio of porosity length to binary separation, $\sqrt{h/a}$, implying for example a ca. 10% variation in gamma ray emission for a quite moderate porosity, h/a ∼ 0.01. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-18210 ER - TY - JOUR A1 - Brand, Ralf A1 - Nosrat, Sanaz A1 - Späth, Constantin A1 - Timme, Sinika T1 - Using COVID-19 Pandemic as a Prism: A Systematic Review of Methodological Approaches and the Quality of Empirical Studies on Physical Activity Behavior Change JF - Frontiers in Sports and Active Living N2 - Background: The COVID-19 pandemic has highlighted the importance of scientific endeavors. The goal of this systematic review is to evaluate the quality of the research on physical activity (PA) behavior change and its potential to contribute to policy-making processes in the early days of COVID-19 related restrictions. Methods: We conducted a systematic review of methodological quality of current research according to PRISMA guidelines using Pubmed and Web of Science, of articles on PA behavior change that were published within 365 days after COVID-19 was declared a pandemic by the World Health Organization (WHO). Items from the JBI checklist and the AXIS tool were used for additional risk of bias assessment. Evidence mapping is used for better visualization of the main results. Conclusions about the significance of published articles are based on hypotheses on PA behavior change in the light of the COVID-19 pandemic. Results: Among the 1,903 identified articles, there were 36% opinion pieces, 53% empirical studies, and 9% reviews. Of the 332 studies included in the systematic review, 213 used self-report measures to recollect prepandemic behavior in often small convenience samples. Most focused changes in PA volume, whereas changes in PA types were rarely measured. The majority had methodological reporting flaws. Few had very large samples with objective measures using repeated measure design (pre and during the pandemic). In addition to the expected decline in PA duration, these studies show that many of those who were active prepandemic, continued to be active during the pandemic. Conclusions: Research responded quickly at the onset of the pandemic. However, most of the studies lacked robust methodology, and PA behavior change data lacked the accuracy needed to guide policy makers. To improve the field, we propose the implementation of longitudinal cohort studies by larger organizations such as WHO to ease access to data on PA behavior, and suggest those institutions set clear standards for this research. Researchers need to ensure a better fit between the measurement method and the construct being measured, and use both objective and subjective measures where appropriate to complement each other and provide a comprehensive picture of PA behavior. KW - meta-science KW - exercise KW - methods KW - quality KW - study designs KW - standards Y1 - 2022 U6 - https://doi.org/10.3389/fspor.2022.864468 SN - 2624-9367 VL - 4 SP - 1 EP - 17 PB - Frontiers CY - Lausanne, Schweiz ER - TY - RPRT A1 - Borck, Rainald A1 - Schrauth, Philipp T1 - Urban pollution BT - A global perspective T2 - CEPA Discussion Papers N2 - We use worldwide satellite data to analyse how population size and density affect urban pollution. We find that density significantly increases pollution exposure. Looking only at urban areas, we find that population size affects exposure more than density. Moreover, the effect is driven mostly by population commuting to core cities rather than the core city population itself. We analyse heterogeneity by geography and income levels. By and large, the influence of population on pollution is greatest in Asia and middle-income countries. A counterfactual simulation shows that PM2.5 exposure would fall by up to 36% and NO2 exposure up to 53% if within countries population size were equalized across all cities. T3 - CEPA Discussion Papers - 60 KW - population density KW - air pollution KW - gridded data Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-572049 SN - 2628-653X IS - 60 ER - TY - JOUR A1 - Jones, Eppie R. A1 - González-Fortes, Gloria M. A1 - Connell, Sarah A1 - Siska, Veronika A1 - Eriksson, Anders A1 - Martiniano, Rui A1 - McLaughlin, Russell L. A1 - Llorente, Marcos Gallego A1 - Cassidy, Lara M. A1 - Gamba, Cristina A1 - Meshveliani, Tengiz A1 - Bar-Yosef, Ofer A1 - Mueller, Werner A1 - Belfer-Cohen, Anna A1 - Matskevich, Zinovi A1 - Jakeli, Nino A1 - Higham, Thomas F. G. A1 - Currat, Mathias A1 - Lordkipanidze, David A1 - Hofreiter, Michael A1 - Manica, Andrea A1 - Pinhasi, Ron A1 - Bradley, Daniel G. T1 - Upper Palaeolithic genomes reveal deep roots of modern Eurasians JF - Nature Communications N2 - We extend the scope of European palaeogenomics by sequencing the genomes of Late Upper Palaeolithic (13,300 years old, 1.4-fold coverage) and Mesolithic (9,700 years old, 15.4-fold) males from western Georgia in the Caucasus and a Late Upper Palaeolithic (13,700 years old, 9.5-fold) male from Switzerland. While we detect Late Palaeolithic-Mesolithic genomic continuity in both regions, we find that Caucasus hunter-gatherers (CHG) belong to a distinct ancient clade that split from western hunter-gatherers similar to 45 kya, shortly after the expansion of anatomically modern humans into Europe and from the ancestors of Neolithic farmers similar to 25 kya, around the Last Glacial Maximum. CHG genomes significantly contributed to the Yamnaya steppe herders who migrated into Europe similar to 3,000 BC, supporting a formative Caucasus influence on this important Early Bronze age culture. CHG left their imprint on modern populations from the Caucasus and also central and south Asia possibly marking the arrival of Indo-Aryan languages. Y1 - 2015 U6 - https://doi.org/10.1038/ncomms9912 SN - 2041-1723 VL - 6 PB - Nature Publishing Group CY - London ER - TY - JOUR A1 - Wagner, Andreas T1 - Unity in diversity BT - integrating different linguistic data in TUSNELDA JF - Interdisciplinary studies on information structure : ISIS ; working papers of the SFB 632 N2 - This paper describes the creation and preparation of TUSNELDA, a collection of corpus data built for linguistic research. This collection contains a number of linguistically annotated corpora which differ in various aspects such as language, text sorts / data types, encoded annotation levels, and linguistic theories underlying the annotation. The paper focuses on this variation on the one hand and the way how these heterogeneous data are integrated into one resource on the other hand. Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-8625 SN - 1866-4725 SN - 1614-4708 IS - 2 SP - 1 EP - 20 ER - TY - RPRT A1 - Drechsler, Denis T1 - Unemployment in Germany and the Eurosclerosis debate BT - Can the Hartz reforms induce higher employment? N2 - Many European countries have experienced a significant increase of unemployment in recent years. This paper reviews several theoretical models that try to explain this phenomenon. Predominantly, these models claim a link between the poor performance of European labor markets and the high level of market regulation. Commonly referred to as the Eurosclerosis debate, prominent approaches consider insider-outsider relationships, search-models, and the influence of hiring and firing costs on equilibrium employment. The paper presents empirical evidence of each model and studies the relevance of the identified rigidities as a determinant of high unemployment in Europe. Furthermore, a case study analyzes the unemployment problem in Germany and critically discusses new reform efforts. In particular this section analyzes whether the recently enacted Hartz reforms can induce higher employment. T3 - Finanzwissenschaftliche Diskussionsbeiträge - 48 Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-9036 ER - TY - GEN A1 - Stone, Kate A1 - Nicenboim, Bruno A1 - Vasishth, Shravan A1 - Rösler, Frank T1 - Understanding the effects of constraint and predictability in ERP T2 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Intuitively, strongly constraining contexts should lead to stronger probabilistic representations of sentences in memory. Encountering unexpected words could therefore be expected to trigger costlier shifts in these representations than expected words. However, psycholinguistic measures commonly used to study probabilistic processing, such as the N400 event-related potential (ERP) component, are sensitive to word predictability but not to contextual constraint. Some research suggests that constraint-related processing cost may be measurable via an ERP positivity following the N400, known as the anterior post-N400 positivity (PNP). The PNP is argued to reflect update of a sentence representation and to be distinct from the posterior P600, which reflects conflict detection and reanalysis. However, constraint-related PNP findings are inconsistent. We sought to conceptually replicate Federmeier et al. (2007) and Kuperberg et al. (2020), who observed that the PNP, but not the N400 or the P600, was affected by constraint at unexpected but plausible words. Using a pre-registered design and statistical approach maximising power, we demonstrated a dissociated effect of predictability and constraint: strong evidence for predictability but not constraint in the N400 window, and strong evidence for constraint but not predictability in the later window. However, the constraint effect was consistent with a P600 and not a PNP, suggesting increased conflict between a strong representation and unexpected input rather than greater update of the representation. We conclude that either a simple strong/weak constraint design is not always sufficient to elicit the PNP, or that previous PNP constraint findings could be an artifact of smaller sample size. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 829 KW - N400 KW - anterior PNP KW - posterior P600 KW - probabilistic processing KW - constraint KW - predictability KW - entropy Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-587594 SN - 1866-8364 IS - 829 ER - TY - JOUR A1 - Stone, Kate A1 - Nicenboim, Bruno A1 - Vasishth, Shravan A1 - Rösler, Frank T1 - Understanding the effects of constraint and predictability in ERP JF - Neurobiology of language N2 - Intuitively, strongly constraining contexts should lead to stronger probabilistic representations of sentences in memory. Encountering unexpected words could therefore be expected to trigger costlier shifts in these representations than expected words. However, psycholinguistic measures commonly used to study probabilistic processing, such as the N400 event-related potential (ERP) component, are sensitive to word predictability but not to contextual constraint. Some research suggests that constraint-related processing cost may be measurable via an ERP positivity following the N400, known as the anterior post-N400 positivity (PNP). The PNP is argued to reflect update of a sentence representation and to be distinct from the posterior P600, which reflects conflict detection and reanalysis. However, constraint-related PNP findings are inconsistent. We sought to conceptually replicate Federmeier et al. (2007) and Kuperberg et al. (2020), who observed that the PNP, but not the N400 or the P600, was affected by constraint at unexpected but plausible words. Using a pre-registered design and statistical approach maximising power, we demonstrated a dissociated effect of predictability and constraint: strong evidence for predictability but not constraint in the N400 window, and strong evidence for constraint but not predictability in the later window. However, the constraint effect was consistent with a P600 and not a PNP, suggesting increased conflict between a strong representation and unexpected input rather than greater update of the representation. We conclude that either a simple strong/weak constraint design is not always sufficient to elicit the PNP, or that previous PNP constraint findings could be an artifact of smaller sample size. KW - N400 KW - anterior PNP KW - posterior P600 KW - probabilistic processing KW - constraint KW - predictability KW - entropy Y1 - 2022 U6 - https://doi.org/10.1162/nol_a_00094 SN - 2641-4368 VL - 4 IS - 2 SP - 221 EP - 256 PB - MIT Press CY - Cambridge, MA, USA ER - TY - CHAP A1 - Dzikovska, Myroslava O. A1 - Callaway, Charles B. A1 - Stone, Matthew A1 - Moore, Johanna D. T1 - Understanding student input for tutorial dialogue in procedural domains N2 - We present an analysis of student language input in a corpus of tutoring dialogue in the domain of symbolic differentiation. Our focus on procedural tutoring makes the dialogue comparable to collaborative problem-solving (CPS). Existing CPS models describe the process of negotiating plans and goals, which also fits procedural tutoring. However, we provide a classification of student utterances and corpus annotation which shows that approximately 28% of non-trivial student language in this corpus is not accounted for by existing models, and addresses other functions, such as evaluating past actions or correcting mistakes. Our analysis can be used as a foundation for improving models of tutoring dialogue. Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-10193 ER - TY - THES A1 - Trautmann, Tina T1 - Understanding global water storage variations using model-data integration T1 - Verständnis der Variabilität globaler Wasserspeicher mittels Modell-Daten Integration N2 - Climate change is one of the greatest challenges to humanity in this century, and most noticeable consequences are expected to be impacts on the water cycle – in particular the distribution and availability of water, which is fundamental for all life on Earth. In this context, it is essential to better understand where and when water is available and what processes influence variations in water storages. While estimates of the overall terrestrial water storage (TWS) variations are available from the GRACE satellites, these represent the vertically integrated signal over all water stored in ice, snow, soil moisture, groundwater and surface water bodies. Therefore, complementary observational data and hydrological models are still required to determine the partitioning of the measured signal among different water storages and to understand the underlying processes. However, the application of large-scale observational data is limited by their specific uncertainties and the incapacity to measure certain water fluxes and storages. Hydrological models, on the other hand, vary widely in their structure and process-representation, and rarely incorporate additional observational data to minimize uncertainties that arise from their simplified representation of the complex hydrologic cycle. In this context, this thesis aims to contribute to improving the understanding of global water storage variability by combining simple hydrological models with a variety of complementary Earth observation-based data. To this end, a model-data integration approach is developed, in which the parameters of a parsimonious hydrological model are calibrated against several observational constraints, inducing GRACE TWS, simultaneously, while taking into account each data’s specific strengths and uncertainties. This approach is used to investigate 3 specific aspects that are relevant for modelling and understanding the composition of large-scale TWS variations. The first study focusses on Northern latitudes, where snow and cold-region processes define the hydrological cycle. While the study confirms previous findings that seasonal dynamics of TWS are dominated by the cyclic accumulation and melt of snow, it reveals that inter-annual TWS variations on the contrary, are determined by variations in liquid water storages. Additionally, it is found to be important to consider the impact of compensatory effects of spatially heterogeneous hydrological variables when aggregating the contribution of different storage components over large areas. Hence, the determinants of TWS variations are scale-dependent and underlying driving mechanism cannot be simply transferred between spatial and temporal scales. These findings are supported by the second study for the global land areas beyond the Northern latitudes as well. This second study further identifies the considerable impact of how vegetation is represented in hydrological models on the partitioning of TWS variations. Using spatio-temporal varying fields of Earth observation-based data to parameterize vegetation activity not only significantly improves model performance, but also reduces parameter equifinality and process uncertainties. Moreover, the representation of vegetation drastically changes the contribution of different water storages to overall TWS variability, emphasizing the key role of vegetation for water allocation, especially between sub-surface and delayed water storages. However, the study also identifies parameter equifinality regarding the decay of sub-surface and delayed water storages by either evapotranspiration or runoff, and thus emphasizes the need for further constraints hereof. The third study focuses on the role of river water storage, in particular whether it is necessary to include computationally expensive river routing for model calibration and validation against the integrated GRACE TWS. The results suggest that river routing is not required for model calibration in such a global model-data integration approach, due to the larger influence other observational constraints, and the determinability of certain model parameters and associated processes are identified as issues of greater relevance. In contrast to model calibration, considering river water storage derived from routing schemes can already significantly improve modelled TWS compared to GRACE observations, and thus should be considered for model evaluation against GRACE data. Beyond these specific findings that contribute to improved understanding and modelling of large-scale TWS variations, this thesis demonstrates the potential of combining simple modeling approaches with diverse Earth observational data to improve model simulations, overcome inconsistencies of different observational data sets, and identify areas that require further research. These findings encourage future efforts to take advantage of the increasing number of diverse global observational data. N2 - Der Klimawandel stellt mit Abstand eine der größten Herausforderungen für die Menschheit in diesem Jahrhundert da, und die spürbarsten Folgen werden voraussichtlich die Auswirkungen auf den Wasserkreislauf sein - insbesondere auf die Verteilung und Verfügbarkeit von Wasser, welches Grundlage allen Lebens dieser Erde ist. In diesem Zusammenhang ist es von entscheidender Bedeutung, besser zu verstehen, wo und wann Wasser verfügbar ist und welche Prozesse natürliche Schwankungen der Wasserspeicher beeinflussen. Obwohl Schätzungen der Gesamtschwankungen der terrestrischen Wasserspeicher (TWS) basierend auf Daten der GRACE-Satelliten vorliegen, stellen diese nur das vertikal integrierte Signal über alles in Eis, Schnee, Bodenfeuchtigkeit, Grundwasser und Oberflächengewässern gespeicherte Wasser dar. Daher sind ergänzende Beobachtungsdaten und hydrologische Modelle notwendig, um die Aufteilung des gemessenen Signals auf verschiedenen Wasserspeicher zu bestimmen und die zugrunde liegenden Prozesse zu verstehen. Die Verwendung von großmaßstäblichen Beobachtungsdaten ist jedoch durch ihre spezifischen Unsicherheiten und die Unfähigkeit, bestimmte Wasserflüsse und -speicher zu messen, eingeschränkt. Hydrologische Modelle hingegen unterscheiden sich stark in ihrer Struktur und Prozessdarstellung und beziehen nur selten zusätzliche Beobachtungsdaten ein, um Unsicherheiten zu minimieren, die sich aus ihrer vereinfachten Darstellung des komplexen Wasserkreislaufs ergeben. In diesem Zusammenhang gibt diese Arbeit einen Beitrag zum besseren Verständnis der Schwankungen globaler Wasserspeicher, indem einfache hydrologische Modelle mit einer Vielzahl sich ergänzender Erdbeobachtungsdaten kombiniert werden. Dafür wird ein Ansatz zur Integration von Modellen und Daten entwickelt, bei dem die Parameter eines einfachen hydrologischen Modells gleichzeitig gegen mehrere Beobachtungsdaten, inklusive GRACE TWS, kalibriert werden, wobei deren spezifischen Stärken und Unsicherheiten berücksichtigt werden. Dieser Ansatz wird genutzt, um drei spezifische Aspekte, die für die Modellierung und das Verständnis der Zusammensetzung großskaliger TWS-Schwankungen relevant sind, zu untersuchen. Die erste Studie konzentriert sich auf die nördlichen Breiten, wo Schnee und Prozesse kalter Regionen den hydrologischen Kreislauf bestimmen. Während die Studie frühere Erkenntnisse darin bestätigt, dass die saisonale Dynamik des TWS von der zyklischen Akkumulation und Schmelze von Schnee dominiert wird, zeigt sie, dass die zwischenjährlichen TWS-Schwankungen im Gegenteil durch Variationen der Flüssigwasserspeicher bestimmt werden. Darüber hinaus wird festgestellt, dass es wichtig ist, die Auswirkungen kompensatorischer Effekte räumlich heterogener hydrologischer Variablen zu berücksichtigen, wenn der Beitrag verschiedener Speicherkomponenten über große Gebiete aggregiert wird. Die Determinanten der TWS-Schwankungen sind skalenabhängig, und die zugrunde liegenden Antriebsmechanismen lassen sich nicht einfach zwischen räumlichen und zeitlichen Skalen übertragen. Diese Ergebnisse werden durch die zweite Studie auch auf globaler Skale bestätigt. Diese zweite Studie zeigt außerdem, dass die Art und Weise, wie Vegetation in hydrologischen Modellen dargestellt wird, einen erheblichen Einfluss auf die Aufteilung der TWS-Variationen hat. Die Verwendung von raum-zeitlich variierenden Erdbeobachtungsdaten zur Parametrisierung der Vegetationsaktivität verbessert nicht nur die Modellleistung erheblich, sondern verringert auch die Parameterequifinalität und somit die Prozessunsicherheiten. Darüber hinaus beeinflusst die Repräsentation der Vegetation drastisch den Einfluss verschiedener Wasserspeicher zur Gesamtvariabilität des TWS und unterstreicht damit die Schlüsselrolle der Vegetation für die Wasserverteilung, insbesondere zwischen unterirdischen und verzögerten Wasserspeichern. Die Studie zeigt jedoch auch, dass die Parameter für den Verringerung der unterirdischen und verzögerten Wasserspeichern, entweder via Evapotranspiration oder via Abfluss, äquivalent sind, und unterstreicht damit die Notwendigkeit weiterer Eingrenzung durch Beobachtungsdaten. Die dritte Studie befasst sich mit der Rolle der Wasserspeicherung in Flüssen, insbesondere mit der Frage, ob es notwendig ist, das rechenintensive Abfluss-Routing für die Kalibrierung und Validierung des Modells gegen GRACE TWS Daten zu berücksichtigen. Die Ergebnisse deuten darauf hin, dass das Abfluss-Routing für die Modellkalibrierung in einem solchen globalen Modell-Daten-Integrationsansatz nicht erforderlich ist, da andere Beobachtungsdaten einen größeren Einfluss haben und die Definierbarkeit bestimmter Modellparameter und damit zusammenhängender Prozesse relevantere Probleme darstellen. Im Gegensatz zur Modellkalibrierung kann die Berücksichtigung von Flusswasserspeichern jedoch den modellierten TWS im Vergleich zu GRACE-Beobachtungen bereits erheblich verbessern und sollte daher bei der Modellevaluierung gegen GRACE-Daten berücksichtigt werden. Über diese spezifischen Ergebnisse hinaus, die zum besseren Verständnis und Modellierung großskaliger TWS-Variationen beitragen, zeigt diese Arbeit das Potenzial der Kombination einfacher Modellierungsansätze mit verschiedenen Erdbeobachtungsdaten zur Verbesserung von Modellsimulationen, zur Überwindung von Inkonsistenzen zwischen verschiedenen Beobachtungsdatensätzen und zur Identifizierung von Themen, die weitere Forschung erfordern. Diese Ergebnisse ermutigen künftige Forschungen, die zunehmende Zahl unterschiedlicher globaler Beobachtungsdaten zu nutzen. KW - global hydrological modeling KW - model-data integration KW - terrestrial water storage variation KW - model calibration KW - globale hydrologische Modellierung KW - Modellkalibrierung KW - Model-Daten Integration KW - Variationen terrestrischer Wasserspeicher Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-565954 ER - TY - GEN A1 - Ciuciu, Adina I. A1 - Cywiński, Piotr J. T1 - Two-photon polymerization of hydrogels – versatile solutions to fabricate well-defined 3D structures N2 - Hydrogels are cross-linked water-containing polymer networks that are formed by physical, ionic or covalent interactions. In recent years, they have attracted significant attention because of their unique physical properties, which make them promising materials for numerous applications in food and cosmetic processing, as well as in drug delivery and tissue engineering. Hydrogels are highly water-swellable materials, which can considerably increase in volume without losing cohesion, are biocompatible and possess excellent tissue-like physical properties, which can mimic in vivo conditions. When combined with highly precise manufacturing technologies, such as two-photon polymerization (2PP), well-defined three-dimensional structures can be obtained. These structures can become scaffolds for selective cell-entrapping, cell/drug delivery, sensing and prosthetic implants in regenerative medicine. 2PP has been distinguished from other rapid prototyping methods because it is a non-invasive and efficient approach for hydrogel cross-linking. This review discusses the 2PP-based fabrication of 3D hydrogel structures and their potential applications in biotechnology. A brief overview regarding the 2PP methodology and hydrogel properties relevant to biomedical applications is given together with a review of the most important recent achievements in the field. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 286 Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-99450 ER - TY - THES A1 - Canil, Laura T1 - Tuning Interfacial Properties in Perovskite Solar Cells through Defined Molecular Assemblies T1 - Anpassung von Grenzflächeneigenschaften von Perowskit-Solarzellen durch den Einsatz von molekularen Schichten N2 - In the frame of a world fighting a dramatic global warming caused by human-related activities, research towards the development of renewable energies plays a crucial role. Solar energy is one of the most important clean energy sources and its role in the satisfaction of the global energy demand is set to increase. In this context, a particular class of materials captured the attention of the scientific community for its attractive properties: halide perovskites. Devices with perovskite as light-absorber saw an impressive development within the last decade, reaching nowadays efficiencies comparable to mature photovoltaic technologies like silicon solar cells. Yet, there are still several roadblocks to overcome before a wide-spread commercialization of this kind of devices is enabled. One of the critical points lies at the interfaces: perovskite solar cells (PSCs) are made of several layers with different chemical and physical features. In order for the device to function properly, these properties have to be well-matched. This dissertation deals with some of the challenges related to interfaces in PSCs, with a focus on the interface between the perovskite material itself and the subsequent charge transport layer. In particular, molecular assemblies with specific properties are deposited on the perovskite surface to functionalize it. The functionalization results in energy level alignment adjustment, interfacial losses reduction, and stability improvement. First, a strategy to tune the perovskite’s energy levels is introduced: self-assembled monolayers of dipolar molecules are used to functionalize the surface, obtaining simultaneously a shift in the vacuum level position and a saturation of the dangling bonds at the surface. A shift in the vacuum level corresponds to an equal change in work function, ionization energy, and electron affinity. The direction of the shift depends on the direction of the collective interfacial dipole. The magnitude of the shift can be tailored by controlling the deposition parameters, such as the concentration of the solution used for the deposition. The shift for different molecules is characterized by several non-invasive techniques, including in particular Kelvin probe. Overall, it is shown that it is possible to shift the perovskite energy levels in both directions by several hundreds of meV. Moreover, interesting insights on the molecules deposition dynamics are revealed. Secondly, the application of this strategy in perovskite solar cells is explored. Devices with different perovskite compositions (“triple cation perovskite” and MAPbBr3) are prepared. The two resulting model systems present different energetic offsets at the perovskite/hole-transport layer interface. Upon tailored perovskite surface functionalization, the devices show a stabilized open circuit voltage (Voc) enhancement of approximately 60 meV on average for devices with MAPbBr3, while the impact is limited on triple-cation solar cells. This suggests that the proposed energy level tuning method is valid, but its effectiveness depends on factors such as the significance of the energetic offset compared to the other losses in the devices. Finally, the above presented method is further developed by incorporating the ability to interact with the perovskite surface directly into a novel hole-transport material (HTM), named PFI. The HTM can anchor to the perovskite halide ions via halogen bonding (XB). Its behaviour is compared to that of another HTM (PF) with same chemical structure and properties, except for the ability of forming XB. The interaction of perovskite with PFI and PF is characterized through UV-Vis, atomic force microscopy and Kelvin probe measurements combined with simulations. Compared to PF, PFI exhibits enhanced resilience against solvent exposure and improved energy level alignment with the perovskite layer. As a consequence, devices comprising PFI show enhanced Voc and operational stability during maximum-power-point tracking, in addition to hysteresis reduction. XB promotes the formation of a high-quality interface by anchoring to the halide ions and forming a stable and ordered interfacial layer, showing to be a particularly interesting candidate for the development of tailored charge transport materials in PSCs. Overall, the results exposed in this dissertation introduce and discuss a versatile tool to functionalize the perovskite surface and tune its energy levels. The application of this method in devices is explored and insights on its challenges and advantages are given. Within this frame, the results shed light on XB as ideal interaction for enhancing stability and efficiency in perovskite-based devices. N2 - Im Kampf gegen den menschengemachten Klimawandel spielt die Forschung und Entwicklung von erneuerbaren Energien eine tragende Rolle. Solarenergie ist eine der wichtigsten grünen Energiequellen und von steigender Bedeutung für die Deckung des globalen Energiebedarfs. In diesem Kontext hat eine bestimme Materialklasse aufgrund ihrer attraktiven Eigenschaften die Aufmerksamkeit der Wissenschaft erregt: Halogenid-Perowskit. Perowskit-Solarzellen haben im letzten Jahrzehnt eine beeindruckende Entwicklung durchgemacht und erreichen heutzutage Effizienzen, die mit weit entwickelten Photovoltaik-Technologien wie Silizium-Solarzellen vergleichbar sind. Jedoch existieren immer noch mehrere Hürden, die einer marktweiten Kommerzialisierung dieser jungen Technologie im Wege stehen. Eines der kritischen Probleme befindet sich an den Grenzflächen. Perowskit-Solarzellen bestehen aus mehreren Schichten mit unterschiedlichen chemischen und physikalischen Eigenschaften. Damit die Solarzelle bestmöglich funktioniert, müssen diese Eigenschaften aufeinander abgestimmt sein. Diese Dissertation beschäftigt sich mit einigen Herausforderungen im Zusammenhang mit Grenzflächen in Perowskit-Solarzellen, dabei liegt der Fokus auf der Grenzfläche zwischen Perowskit-Absorber und der angrenzenden Ladungstransportschicht. Insbesondere werden organische Moleküle mit spezifischen Eigenschaften verwendet um die Oberfläche des Perowskiten zu funktionalisieren. Dadurch wird eine Bandanpassung erreicht, Grenzflächenverluste reduziert und die Stabilität der Solarzellen erhöht. Zunächst wird eine Strategie zum Anpassen der Bandenergien vorgestellt: Selbst-organisierende Monoschichten dipolarer Moleküle werden auf die Perowskit-Oberfläche abgeschieden, um diese zu funktionalisieren. Dadurch wird eine Anpassung des Energie-Levels im Perowskiten und die Sättigung von ungebundenen Elektronenbindungen (engl. dangling bonds) an der Oberfläche erreicht. Die Richtung der Energielevel-Verschiebung hängt von der Richtung des kollektiven Grenzflächen-Dipols ab. Der Betrag der Energielevel-Verschiebung kann über die Depositionsparameter während der Schichtherstellung eingestellt werden. Die Energielevel-Verschiebung bei der Verwendung verschiedener Moleküle wird mit Hilfe verschiedener non-invasiver Charakterisierungsmethoden untersucht, insbesondere mit der Hilfe von Kelvin-Sonde Messungen. Diese Messungen ermöglichen interessante Erkenntnisse über die Dynamik der Deposition der Moleküle. Es ist möglich die Energielevel in beide Richtungen um mehrere hundert meV zu verschieben. Als Zweites wird die Anwendung dieser Stategie in Perowskit-Solarzellen erforscht. Solarzellen mit Perowskit-Absorbern unterschiedlicher Zusammensetzung (“Dreifach-Kationen-Perowskit” und MAPbBr3) werden präpariert; die beiden Modellsysteme besitzen dann unterschiedliche energetische Offsets an der Perowskit-Lochleiter Grenzfläche. Mit einer maßgeschneiderter Funktionalisierung der Perowskit-Oberfläche zeigen die MAPbBr3 Solarzellen eine permanente Verbesserung der offene-Klemmen-Spannung (engl. open circuit voltage, Voc) um durchschnittlich 60 meV, während der Einfluss auf die Solarzellen mit Dreifach-Kationen-Perowskit gering ist. Dies zeigt, dass die vorgestellte Methode zur Bandanpassung funktioniert, aber ihre Effektivität zudem von weiteren Faktoren abhängt: Die Relevanz des energetischen Offsets im Vergleich zu anderen Verlustmechanismen beeinflusst unter anderem die Effektivität der Funktionalisierung. Abschließend wird beschrieben, wie die präsentierte Methode zur Bandanpassung weiterentwickelt wird, indem das Vermögen, mit der Perowskit-Oberfläche zu interagieren, direkt in einen neuartigen Lochleiter („PFI“) integriert wird. Der Lochleiter kann sich über Halogenbindungen an den Perowskiten anlagern. Das Verhalten von PFI wird verglichen mit dem eines anderen Lochleiters („PF“), welcher die fast gleiche chemische Struktur und sehr ähnliche Eigenschaften aufweist, ausgenommen der Fähigkeit eine Halogenbindung zu formen. Die PFI-Perowskit und PF-Perowskit Interaktion wird durch UV-Vis Spektroskopie, Rasterkraftmikroskopie und Kelvin-Sonde Messungen, kombiniert mit Simulationen, charakterisiert. Beim direkten Vergleich von PFI und PF zeigt sich die Bildung der Halogenbindung in einer bei PFI verbesserten Widerstandskraft gegen Lösungsmittel und Bandanpassung zum Perowskiten. Beim Folgerichtig zeigen Solarzellen mit PFI zusätzlich zu einer verringerten Hysterese einen höheren Voc und eine erhöhte Stabilität während des Betriebs unter Maximum-Power-Point Tracking Zusammenfassend stellt diese Dissertation somit ein vielseitiges Werkzeug zur Funktionalisierung von Perowskit-Oberflächen und der dadurch erreichten Bandanpassung vor. Die Anwendung dieses Werkzeugs an Solarzellen wird erprobt und Einsichten in seine Vorteile und Nachteile erlangt. Die Halogenbindung wird als spezifische Interaktion identifiziert, die sich ideal zur Steigerung von Effizienz und Stabilität von Perowskit-basierten optoelektronischen Bauteilen erweisen könnte. KW - photovoltaic KW - perovskite solar cells KW - interfaces KW - energy levels KW - halogen bonding KW - Grenzflächen KW - Perowskit Solarzellen KW - Photovoltaik KW - Bandenenergien KW - Halogenbindung Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-546333 ER - TY - JOUR A1 - Francisco Vásquez Carruthers, Juan T1 - Transitional Justice and Political Opportunism JF - Transitional Justice : Theoretical and Practical Approaches (Potsdamer Studien zu Staat, Recht und Politik ; 7) N2 - This paper aims to contribute a different approach to transitional justice, one in which political decisions are rocketed to the forefront of the research. Theory asserts that, after a transition to democracy, it is the constituency who defines the direction a country will take. Therefore, pleasing them should be at the fore of the responses taken by those in power. However, reality distances itself from theory. History provides us with many examples of the contrary, which indicates that the politicization of transitional justice is an ever-present event. The first section will outline current definitions and obstacles faced by transitional justice, focusing on the implicit ties between them and the aforementioned politicization. An original categorization of Transitional Justice as a method of analysis will also be introduced, which I denominate Political Opportunism. The case of Argentina, a country that is usually described as a model to export but that after 35 years is still dealing with the consequences brought by the contradictions of using several methods of justice, will then be reinterpreted through this perspective. At the end of the paper, the inevitable question will be posed: can this new angle be exported and implemented in every transition? Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-570153 SN - 978-3-86956-473-9 SN - 1869-2443 SN - 1867-2663 IS - 7 SP - 39 EP - 71 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Maaser, Lucas T1 - Transitional Justice and Nonviolent Resistance BT - Mutually Reinforcing Frameworks for the Consolidation of Democracies? JF - Transitional Justice : Theoretical and Practical Approaches (Potsdamer Studien zu Staat, Recht und Politik ; 7) N2 - At different times and places, civic engagement in nonviolent resistance (NVR) has repeatedly shown to be an effective tool in times of conflict to initiate societal change from below. History teaches us that there have been successes (Mahatma Gandhi in India) and failures (the Tiananmen Square protests in China). Along with the recognition of the duality between transformative potential and stark consequences, the historical development of NVR was accompanied by the emergence of scholarly debate, fractured along disputes around purpose, character and effectivity of nonviolent actions taken by civil society stakeholders engaged in making their voices heard. One of the field’s current points of interest is the examination of the long-term effects of NVR movements resulting in societal transformation on the stability and adequacy of a subsequently altered or emerging democracy, suggesting that NVR contributes positively to the sustainable and representative design of an egalitarian governing system. The conclusion of the Nepalese civil war in 2006 should pose as an unambiguous example for the illustration of this phenomenon, but simultaneously raises the question why there was no successful implementation of a transitional process focusing on the needs of the victims. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-570470 SN - 978-3-86956-473-9 SN - 1869-2443 SN - 1867-2663 IS - 7 SP - 139 EP - 165 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - BOOK A1 - Weiß, Norman A1 - Verlaan, Stephanie A1 - Vasquez Carruthers, Juan Francisco A1 - Mair, Theresa A1 - Conner, Sean A1 - Maaser, Lucas A1 - Röthlisberger, Livia ED - Weiß, Norman T1 - Transitional Justice BT - Theoretical and Practical Approaches T3 - Potsdamer Studien zu Staat, Recht und Politik N2 - This publication deals with the topic of transitional justice. In six case studies, the authors link theoretical and practical implications in order to develop some innovative approaches. Their proposals might help to deal more effectively with the transition of societies, legal orders and political systems. Young academics from various backgrounds provide fresh insights and demonstrate the relevance of the topic. The chapters analyse transitions and conflicts in Sierra Leone, Argentina, Nicaragua, Nepal, and South Sudan as well as Germany’s colonial genocide in Namibia. Thus, the book provides the reader with new insights and contributes to the ongoing debate about transitional justice. N2 - Gegenstand dieser Publikation ist das Thema „Transitional Justice“. In sechs Fallstudien verknüpfen die Autoren theoretische und praktische Implikationen, um innovative Ansätze zu entwickeln. Ihre Vorschläge wollen dazu beitragen, den Übergangsprozess von Gesellschaften, Rechtsordnungen und politischen Systemen effektiver zu gestalten. Nachwuchswissenschaftler mit unterschiedlichem fachlichem Hintergrund geben hier neue Einblicke und zeigen die fortdauernde Relevanz des Themas. Die Kapitel analysieren Übergänge und Konflikte in Sierra Leone, Argentinien, Nicaragua, Nepal und Süd-Sudan sowie den kolonialen Völkermord in Namibia. So liefert das Buch dem Leser neue Erkenntnisse und trägt zur laufenden Debatte über das Thema „Transitional Justice“ bei. T3 - Potsdamer Studien zu Staat, Recht und Politik - 7 KW - transitional justice KW - transformation KW - transformative justice KW - reconciliation KW - political opportunism KW - Übergangsjustiz KW - Transformation KW - Versöhnung KW - Demokratisierung Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431711 SN - 978-3-86956-473-9 SN - 1869-2443 SN - 1867-2663 IS - 7 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Mair, Theresa T1 - Transforming Transitional Justice to Address Colonial Crime BT - The Nama’s and Herero’s Claim for Justice for Germany’s Colonial Genocide in Namibia JF - Transitional Justice : Theoretical and Practical Approaches (Potsdamer Studien zu Staat, Recht und Politik ; 7) N2 - While the concept of transitional justice and its range of measures have gained importance on an international level to come to terms with major crimes of the past, colonial crimes and mass violence committed by Western actors have not been addressed by transitional justice so far. In this chapter, the Herero’s and Nama’s struggle for justice for the genocide on their ancestors by Germany from 1904 – 1908 and the arising challenges are set in relation to conceptual debates in the field of transitional justice. Building on current debates in the field, suggesting more structural and transformative conceptualizations of transitional justice and an approach ‘from below’, it is argued that decolonial activism of formerly colonized communities and transitional justice debates can inform each other in a dialogic and fruitful form to formulate suggestions for a process towards post-colonial justice. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-570160 SN - 978-3-86956-473-9 SN - 1869-2443 SN - 1867-2663 IS - 7 SP - 73 EP - 109 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - CHAP A1 - Abdennadher, Slim A1 - Ismail, Haythem A1 - Khoury, Frederick T1 - Transforming imperative algorithms to constraint handling rules N2 - Different properties of programs, implemented in Constraint Handling Rules (CHR), have already been investigated. Proving these properties in CHR is fairly simpler than proving them in any type of imperative programming language, which triggered the proposal of a methodology to map imperative programs into equivalent CHR. The equivalence of both programs implies that if a property is satisfied for one, then it is satisfied for the other. The mapping methodology could be put to other beneficial uses. One such use is the automatic generation of global constraints, at an attempt to demonstrate the benefits of having a rule-based implementation for constraint solvers. Y1 - 2010 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-41533 ER - TY - JOUR A1 - Röthlisberger, Livia T1 - Transformative Justice in South Sudan BT - The Transformative Potential of a Contextualized Transitional Justice Process JF - Transitional Justice : Theoretical and Practical Approaches (Potsdamer Studien zu Staat, Recht und Politik ; 7) N2 - This chapter takes the ongoing conflict in South Sudan as a starting point for assessing the concept of transitional justice as such and its implementation in the country in particular. Following a brief description of the conflict and the peace processes, the author sheds light on the shortcomings of the established concept of transitional justice in the situation at hand. Then, the author outlines the alternate concept of transformational justice und takes a closer look at its implications on the situation in South Sudan. The author highlights existing initiatives of transformative justice and is very much in favour of their victim-centered approach. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-570480 SN - 978-3-86956-473-9 SN - 1869-2443 SN - 1867-2663 IS - 7 SP - 167 EP - 191 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - CHAP A1 - Yli-Jyrä, Anssi T1 - Transducers from parallel replace rules and modes with generalized lenient composition N2 - Generalized Two-Level Grammar (GTWOL) provides a new method for compilation of parallel replacement rules into transducers. The current paper identifies the role of generalized lenient composition (GLC) in this method. Thanks to the GLC operation, the compilation method becomes bipartite and easily extendible to capture various application modes. In the light of three notions of obligatoriness, a modification to the compilation method is proposed. We argue that the bipartite design makes implementation of parallel obligatoriness, directionality, length and rank based application modes extremely easy, which is the main result of the paper. Y1 - 2008 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-27246 ER - TY - JOUR A1 - Prasad, Sushma A1 - Baier, Janina T1 - Tracking the impact of mid- to late Holocene climate change and anthropogenic activities on Lake Holzmaar using an updated Holocene chronology JF - Global and planetary change N2 - The mid- to late Holocene interval is characterised by a highly variable climate in response to a gradual change in orbital insolation. The seasonal impact of these changes on the Eifel Maar region is not yet well documented largely due to uncertainties about the completeness of this archive ("missing varves" in the well known Lake Holzmaar) and a limited understanding of the factors (e.g. temperature, precipitation) influencing the seasonality archived within the lamination/varves. In this study we approach these challenges from a different perspective. Using detailed microfacies investigations we: (1) demonstrate that the ambiguity about the "missing varves" is related to the climate induced complex biotic and abiotic laminations that led to mis-identification of varves; (2) use a combination of detailed microfacies investigations (varve structure, seasonality of biotic and abiotic signals), lamination quality, varve counts on multiple cores, published and new radiocarbon dates to develop a continuous master chronology based on the Bayesian modelling approach. The dates of major climate, volcanic, and archaeological event(s) determined using our model are in good agreement with the independently determined ages of the same events from other archives, confirming the accuracy of our age model; (3) test the sensitivity of the seasonal proxies to the available data on mid-Holocene changes in temperature and precipitation; (4) demonstrate that the changes in lake eutrophicity are correlative with temperature changes in NW Europe and probably triggered by solar variability; and (5) show that the early Iron Age onset of eutrophication in Lake Holzmaar was climate induced and began several decades before the impact of anthropogenic activity was seen in the form of intensified detrital erosion in the catchment area. Our work has implications for understanding the impact of climate change and anthropogenic activities on limnological systems. (C) 2014 Elsevier B.V. All rights reserved. KW - Lake Holzmaar KW - varves KW - microfacies KW - Bayesian modelling KW - Iron Age KW - Ulmener Maar Tephra Y1 - 2014 U6 - https://doi.org/10.1016/j.gloplacha.2014.08.020 SN - 0921-8181 SN - 1872-6364 VL - 122 SP - 251 EP - 264 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Najarro, F. A1 - Puls, Joachim A1 - Herrero, A. A1 - Hanson, M. M. A1 - Martín-Pintado, J. A1 - Hillier, D. J. T1 - Tracking the Clumping in OB Stars from UV to radio N2 - We review different line and continua diagnostics from the UV to radio, which can be utilized to simultaneously constrain the clumping structure throughout the stellar wind of massive OB stars. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17701 ER - TY - JOUR A1 - Timme, Sinika A1 - Wolff, Wanja A1 - Englert, Chris A1 - Brand, Ralf T1 - Tracking Self-Control – Task Performance and Pupil Size in a Go/No-Go Inhibition Task JF - Frontiers in Psychology N2 - There is an ongoing debate about how to test and operationalize self-control. This limited understanding is in large part due to a variety of different tests and measures used to assess self-control, as well as the lack of empirical studies examining the temporal dynamics during the exertion of self-control. In order to track changes that occur over the course of exposure to a self-control task, we investigate and compare behavioral, subjective, and physiological indicators during the exertion of self-control. Participants completed both a task requiring inhibitory control (Go/No-Go task) and a control task (two-choice task). Behavioral performance and pupil size were measured during the tasks. Subjective vitality was measured before and after the tasks. While pupil size and subjective vitality showed similar trajectories in the two tasks, behavioral performance decreased in the inhibitory control-demanding task, but not in the control task. However, behavioral, subjective, and physiological measures were not significantly correlated. These results suggest that there is a disconnect between different measures of self-control with high intra- and interindividual variability. Theoretical and methodological implications for self-control theory and future empirical work are discussed. KW - self-control KW - response inhibition KW - psychophysiological KW - behavioral and self-report measures KW - pupil diameter Y1 - 2022 U6 - https://doi.org/10.3389/fpsyg.2022.915016 SN - 1664-1078 VL - 13 PB - Frontiers CY - Lausanne, Schweiz ER - TY - JOUR A1 - Eckert, Silvia A1 - Herden, Jasmin A1 - Stift, Marc A1 - Durka, Walter A1 - Kleunen, Mark van A1 - Joshi, Jasmin T1 - Traces of genetic but not epigenetic adaptation in the invasive goldenrod Solidago canadensis despite the absence of population structure JF - Frontiers in Ecology and Evolution N2 - Biological invasions may result from multiple introductions, which might compensate for reduced gene pools caused by bottleneck events, but could also dilute adaptive processes. A previous common-garden experiment showed heritable latitudinal clines in fitness-related traits in the invasive goldenrod Solidago canadensis in Central Europe. These latitudinal clines remained stable even in plants chemically treated with zebularine to reduce epigenetic variation. However, despite the heritability of traits investigated, genetic isolation-by-distance was non-significant. Utilizing the same specimens, we applied a molecular analysis of (epi)genetic differentiation with standard and methylation-sensitive (MSAP) AFLPs. We tested whether this variation was spatially structured among populations and whether zebularine had altered epigenetic variation. Additionally, we used genome scans to mine for putative outlier loci susceptible to selection processes in the invaded range. Despite the absence of isolation-by-distance, we found spatial genetic neighborhoods among populations and two AFLP clusters differentiating northern and southern Solidago populations. Genetic and epigenetic diversity were significantly correlated, but not linked to phenotypic variation. Hence, no spatial epigenetic patterns were detected along the latitudinal gradient sampled. Applying genome-scan approaches (BAYESCAN, BAYESCENV, RDA, and LFMM), we found 51 genetic and epigenetic loci putatively responding to selection. One of these genetic loci was significantly more frequent in populations at the northern range. Also, one epigenetic locus was more frequent in populations in the southern range, but this pattern was lost under zebularine treatment. Our results point to some genetic, but not epigenetic adaptation processes along a large-scale latitudinal gradient of S. canadensis in its invasive range. KW - AFLP KW - MSAP KW - cytosine methylation KW - spatial autocorrelation KW - genome scan Y1 - 2022 U6 - https://doi.org/10.3389/fevo.2022.856453 SN - 2296-701X VL - 10 SP - 1 EP - 17 PB - Frontiers CY - Lausanne, Schweiz ER - TY - THES A1 - Drobyshev, Evgenii T1 - Toxic or beneficial? What is the role of food-relevant selenium species selenoneine? T1 - Giftig oder nützlich? Welche Rolle spielt die lebensmittelrelevante Selenspezies Selenonein? N2 - Selenium (Se) is an essential trace element that is ubiquitously present in the environment in small concentrations. Essential functions of Se in the human body are manifested through the wide range of proteins, containing selenocysteine as their active center. Such proteins are called selenoproteins which are found in multiple physiological processes like antioxidative defense and the regulation of thyroid hormone functions. Therefore, Se deficiency is known to cause a broad spectrum of physiological impairments, especially in endemic regions with low Se content. Nevertheless, being an essential trace element, Se could exhibit toxic effects, if its intake exceeds tolerable levels. Accordingly, this range between deficiency and overexposure represents optimal Se supply. However, this range was found to be narrower than for any other essential trace element. Together with significantly varying Se concentrations in soil and the presence of specific bioaccumulation factors, this represents a noticeable difficulty in the assessment of Se epidemiological status. While Se is acting in the body through multiple selenoproteins, its intake occurs mainly in form of small organic or inorganic molecular mass species. Thus, Se exposure not only depends on daily intake but also on the respective chemical form, in which it is present. The essential functions of selenium have been known for a long time and its primary forms in different food sources have been described. Nevertheless, analytical capabilities for a comprehensive investigation of Se species and their derivatives have been introduced only in the last decades. A new Se compound was identified in 2010 in the blood and tissues of bluefin tuna. It was called selenoneine (SeN) since it is an isologue of naturally occurring antioxidant ergothioneine (ET), where Se replaces sulfur. In the following years, SeN was identified in a number of edible fish species and attracted attention as a new dietary Se source and potentially strong antioxidant. Studies in populations whose diet largely relies on fish revealed that SeN represents the main non-protein bound Se pool in their blood. First studies, conducted with enriched fish extracts, already demonstrated the high antioxidative potential of SeN and its possible function in the detoxification of methylmercury in fish. Cell culture studies demonstrated, that SeN can utilize the same transporter as ergothioneine, and SeN metabolite was found in human urine. Until recently, studies on SeN properties were severely limited due to the lack of ways to obtain the pure compound. As a predisposition to this work was firstly a successful approach to SeN synthesis in the University of Graz, utilizing genetically modified yeasts. In the current study, by use of HepG2 liver carcinoma cells, it was demonstrated, that SeN does not cause toxic effectsup to 100 μM concentration in hepatocytes. Uptake experiments showed that SeN is not bioavailable to the used liver cells. In the next part a blood-brain barrier (BBB) model, based on capillary endothelial cells from the porcine brain, was used to describe the possible transfer of SeN into the central nervous system (CNS). The assessment of toxicity markers in these endothelial cells and monitoring of barrier conditions during transfer experiments demonstrated the absence of toxic effects from SeN on the BBB endothelium up to 100 μM concentration. Transfer data for SeN showed slow but substantial transfer. A statistically significant increase was observed after 48 hours following SeN incubation from the blood-facing side of the barrier. However, an increase in Se content was clearly visible already after 6 hours of incubation with 1 μM of SeN. While the transfer rate of SeN after application of 0.1 μM dose was very close to that for 1 μM, incubation with 10 μM of SeN resulted in a significantly decreased transfer rate. Double-sided application of SeN caused no side-specific transfer of SeN, thus suggesting a passive diffusion mechanism of SeN across the BBB. This data is in accordance with animal studies, where ET accumulation was observed in the rat brain, even though rat BBB does not have the primary ET transporter – OCTN1. Investigation of capillary endothelial cell monolayers after incubation with SeN and reference selenium compounds showed no significant increase of intracellular selenium concentration. Speciesspecific Se measurements in medium samples from apical and basolateral compartments, as good as in cell lysates, showed no SeN metabolization. Therefore, it can be concluded that SeN may reach the brain without significant transformation. As the third part of this work, the assessment of SeN antioxidant properties was performed in Caco-2 human colorectal adenocarcinoma cells. Previous studies demonstrated that the intestinal epithelium is able to actively transport SeN from the intestinal lumen to the blood side and accumulate SeN. Further investigation within current work showed a much higher antioxidant potential of SeN compared to ET. The radical scavenging activity after incubation with SeN was close to the one observed for selenite and selenomethionine. However, the SeN effect on the viability of intestinal cells under oxidative conditions was close to the one caused by ET. To answer the question if SeN is able to be used as a dietary Se source and induce the activity of selenoproteins, the activity of glutathione peroxidase (GPx) and the secretion of selenoprotein P (SelenoP) were measured in Caco-2 cells, additionally. As expected, reference selenium compounds selenite and selenomethionine caused efficient induction of GPx activity. In contrast to those SeN had no effect on GPx activity. To examine the possibility of SeN being embedded into the selenoproteome, SelenoP was measured in a culture medium. Even though Caco-2 cells effectively take up SeN in quantities much higher than selenite or selenomethionine, no secretion of SelenoP was observed after SeN incubation. Summarizing, we can conclude that SeN can hardly serve as a Se source for selenoprotein synthesis. However, SeN exhibit strong antioxidative properties, which appear when sulfur in ET is exchanged by Se. Therefore, SeN is of particular interest for research not as part of Se metabolism, but important endemic dietary antioxidant. N2 - Selen (Se) ist ein essentielles Spurenelement, das in geringen Konzentrationen ubiquitär in der Umwelt vorkommt. Essentielle Funktionen von Se im menschlichen Körper manifestieren sich in einer Vielzahl von Proteinen, die Selenocystein als aktives Zentrum enthalten. Solche Proteine werden Selenoproteine genannt, die in zahlreichen physiologischen Prozessen wie der antioxidativen Abwehr und der Regulierung der Schilddrüsenhormonfunktionen vorkommen. Daher ist bekannt, dass ein Se-Mangel ein breites Spektrum physiologischer Beeinträchtigungen verursacht, insbesondere in solchen Regionen mit niedrigem Se-Bodengahlten. Dennoch kann Se als essentielles Spurenelement auch toxische Wirkungen entfalten, wenn seine Aufnahme das tolerierbare Maß überschreitet. Dementsprechend stellt dieser Bereich zwischen Mangel und Überbelichtung eine optimale Se-Versorgung dar. Dieser Bereich erwies sich jedoch als enger als bei jedem anderen essentiellen Spurenelement. Zusammen mit stark schwankenden SeKonzentrationen im Boden und dem Vorliegen spezifischer Bioakkumulationsfaktoren stellt dies eine deutliche Schwierigkeit bei der Beurteilung des epidemiologischen Selenstatus dar. Während im Körper mehrere Selenoproteine vorliegen, erfolgt seine Aufnahme hauptsächlich in Form kleiner organischer oder anorganischer Moleküle. Somit hängt die Se-Exposition nicht nur von der täglichen Aufnahme ab, sondern auch von der jeweiligen chemischen Form, in der es vorliegt. Die essentiellen Funktionen von Selen sind seit langem bekannt und seine Primärformen in verschiedenen Nahrungsquellen dominierenden Formen wurden bereits gut beschrieben. Dennoch wurden erst in den letzten Jahrzehnten neue analytische Möglichkeiten für eine umfassendere Untersuchung von Se-Spezies und ihren Derivaten entwickelt. Beispielsweise wurde 2010 eine neue Se-Verbindung im Blut und im Gewebe von Rotem Thunfisch identifiziert. Es wurde Selenonein (SeN) genannt, da es ein Isolog des natürlich vorkommenden Antioxidans Ergothionein (ET) ist, bei dem Se durch Schwefel ersetzt ist. In den folgenden Jahren wurde SeN in einer Reihe von essbaren Fischarten identifiziert und erregte einerseits als neue Nahrungsquelle für Se und andererseits als potenziell starkes Antioxidans Aufmerksamkeit. Studien an Probanden, deren Ernährung hauptsächlich von Fisch geprägt ist, haben gezeigt, dass SeN den hauptsächlichen nicht-proteingebundenen Se-Pool in ihrem Blut darstellt. Erste Studien mit angereicherten Fischextrakten zeigten bereits das hohe antioxidative Potenzial von SeN und seine mögliche Funktion bei der Entgiftung von Methylquecksilber im Fisch. Zellkulturstudien zeigten, dass SeN den gleichen Transporter wie Ergothionein nutzen kann und ein weiterer SeN-Metabolit wurde im menschlichen Urin gefunden. Bis vor kurzem waren Studien zu den Eigenschaften von SeN aufgrund fehlender Möglichkeiten, die reine Verbindung zu erwerben, stark eingeschränkt. Als wichtige Grundlage für die vorliegende Arbeit diente zunächst die erfolgreiche Synthese des SeN, welche an der Universität Graz unter Verwendung gentechnisch veränderter Hefen erfolgte. In der aktuellen Studie wurde unter Verwendung von HepG2-Leberkarzinomzellen gezeigt, dass SeN in physiologisch relevanten Konzentrationen keine toxischen Effekte in diesen Hepatozyten induziert. Bioverfügbarkeitsexperimente zeigten, dass SeN für die verwendeten Leberzellen nicht bioverfügbar ist. Im nächsten Teil wurde ein Modell der Blut-Hirn-Schranke (BHS) verwendet, das auf kapillaren Endothelzellen aus dem Schweinehirn basiert, um den möglichen Transfer von SeN in das zentrale Nervensystem (ZNS) zu untersuchen. Die Bewertung von Toxizitätsmarkern in diesen Endothelzellen und die online Überwachung der Barriere-Bedingungen während der Transferexperimente zeigten, dass bei physiologisch relevanten Konzentrationen keine toxischen Wirkungen von SeN auf das BHS-Endothel auftreten. Daten bezüglich des Übergangs der Selenspezies SeN zeigten zwar eine langsame, jedoch eine nicht zu vernachlässigenden Menge, die die Barriere passieren kann. Die gleichzeitige Inkubation von SeN auf beiden Barriere-Seiten verursachte keinen seitenspezifischen Transfer von SeN, was auf einen passiven Diffusionsmechanismus von SeN über die BHS hindeutet. Diese Daten stimmen mit Tierstudien überein, in denen eine ET-Akkumulation im Rattengehirn beobachtet wurde, obwohl die BHS der Ratte nicht über den primären ET-Transporter – OCTN1 – verfügt. Die Untersuchung von Monolayern aus kapillaren Endothelzellen nach Inkubation mit SeN und Referenzselenverbindungen zeigte keinen signifikanten Anstieg der intrazellulären Selenkonzentration. Speziesspezifische Se-Messungen in Mediumproben aus den apikalen und basolateralen Kompartimenten, sowie in den Zelllysaten zeigten keine SeN-Metabolisierung. Daraus kann geschlossen werden, dass SeN das Gehirn ohne signifikante Transformation erreichen kann. Als dritter Teil dieser Arbeit wurde die Bewertung der antioxidativen Eigenschaften von SeN in menschlichen Caco-2, also kolorektale Adenokarzinomzellen, durchgeführt. Frühere Studien zeigten, dass das Darmepithel in der Lage ist, SeN aktiv vom Darmlumen zur Blutseite zu transportieren und dort SeN anzureichern. Weitere Untersuchungen im Rahmen der aktuellen Arbeiten zeigten ein viel höheres antioxidatives Potenzial von SeN im Vergleich zu ET. Die Aktivität als Radikalfänger nach Inkubation mit SeN war ähnlich wie bei Selenit und Selenomethionin. Wobei die Wirkung von SeN auf die Lebensfähigkeit von Darmzellen unter oxidativen Bedingungen jedoch ähnlich der durch ET verursachten war. Um die Frage zu beantworten, ob SeN als diätetische Se-Quelle verwendet werden kann um die Aktivität von Selenoproteinen zu induzieren, wurden zusätzlich die Aktivität der Glutathionperoxidase (GPx) und die Sekretion von Selenoprotein P (SelenoP) in Caco-2-Zellen gemessen. Wie erwartet, bewirkten die Referenz-Selenverbindungen Selenit und Selenomethionin eine effiziente Induktion der GPx-Aktivität, im Gegensatz zu diesen hatte SeN keinen Einfluss auf die GPx-Aktivität. Um die Möglichkeit einer Einbettung von SeN in das Selenoproteom zu untersuchen, wurde SelenoP im Kulturmedium gemessen. Obwohl Caco-2-Zellen SeN effektiv in viel höherenMengen als Selenit oder Selenomethionin aufnehmen, wurde nach der SeN-Inkubation keine Sekretion von SelenoP beobachtet. Zusammenfassend können wir schlussfolgern, dass SeN kaum als Se-Quelle für die Selenoproteinsynthese dienen kann. SeN weist jedoch starke antioxidative Eigenschaften auf, die auftreten, wenn Schwefel in ET durch Se ausgetauscht wird. Daher ist SeN von besonderem Interesse für die Forschung, nicht als Teil des Se-Stoffwechsels, sondern als wichtiges endemisches diätetisches Antioxidans. KW - selenium KW - selenoneine KW - HepG2 KW - Caco-2 KW - PBCEC KW - Caco-2 KW - HepG2 KW - PBCEC KW - Selen KW - Selenonein Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-573794 ER - TY - JOUR A1 - Corbett, Tim A1 - Siegel, Björn A1 - Thulin, Mirjam T1 - Towards Pluricultural and Connected Histories BT - Intersections between Jewish and Habsburg Studies JF - PaRDeS Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-645988 SN - 978-3-86956-574-3 SN - 1614-6492 SN - 1862-7684 IS - 29 SP - 15 EP - 27 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Sposini, Vittoria A1 - Krapf, Diego A1 - Marinari, Enzo A1 - Sunyer, Raimon A1 - Ritort, Felix A1 - Taheri, Fereydoon A1 - Selhuber-Unkel, Christine A1 - Benelli, Rebecca A1 - Weiss, Matthias A1 - Metzler, Ralf A1 - Oshanin, Gleb T1 - Towards a robust criterion of anomalous diffusion JF - Communications Physics N2 - Anomalous-diffusion, the departure of the spreading dynamics of diffusing particles from the traditional law of Brownian-motion, is a signature feature of a large number of complex soft-matter and biological systems. Anomalous-diffusion emerges due to a variety of physical mechanisms, e.g., trapping interactions or the viscoelasticity of the environment. However, sometimes systems dynamics are erroneously claimed to be anomalous, despite the fact that the true motion is Brownian—or vice versa. This ambiguity in establishing whether the dynamics as normal or anomalous can have far-reaching consequences, e.g., in predictions for reaction- or relaxation-laws. Demonstrating that a system exhibits normal- or anomalous-diffusion is highly desirable for a vast host of applications. Here, we present a criterion for anomalous-diffusion based on the method of power-spectral analysis of single trajectories. The robustness of this criterion is studied for trajectories of fractional-Brownian-motion, a ubiquitous stochastic process for the description of anomalous-diffusion, in the presence of two types of measurement errors. In particular, we find that our criterion is very robust for subdiffusion. Various tests on surrogate data in absence or presence of additional positional noise demonstrate the efficacy of this method in practical contexts. Finally, we provide a proof-of-concept based on diverse experiments exhibiting both normal and anomalous-diffusion. Y1 - 2022 U6 - https://doi.org/10.1038/s42005-022-01079-8 SN - 2399-3650 VL - 5 PB - Springer Nature CY - London ER - TY - JOUR A1 - Tofelde, Stefanie A1 - Bernhardt, Anne A1 - Guerit, Laure A1 - Romans, Brian W. T1 - Times Associated With Source-to-Sink Propagation of Environmental Signals During Landscape Transience JF - Frontiers in Earth Science N2 - Sediment archives in the terrestrial and marine realm are regularly analyzed to infer changes in climate, tectonic, or anthropogenic boundary conditions of the past. However, contradictory observations have been made regarding whether short period events are faithfully preserved in stratigraphic archives; for instance, in marine sediments offshore large river systems. On the one hand, short period events are hypothesized to be non-detectable in the signature of terrestrially derived sediments due to buffering during sediment transport along large river systems. On the other hand, several studies have detected signals of short period events in marine records offshore large river systems. We propose that this apparent discrepancy is related to the lack of a differentiation between different types of signals and the lack of distinction between river response times and signal propagation times. In this review, we (1) expand the definition of the term ‘signal’ and group signals in sub-categories related to hydraulic grain size characteristics, (2) clarify the different types of ‘times’ and suggest a precise and consistent terminology for future use, and (3) compile and discuss factors influencing the times of signal transfer along sediment routing systems and how those times vary with hydraulic grain size characteristics. Unraveling different types of signals and distinctive time periods related to signal propagation addresses the discrepancies mentioned above and allows a more comprehensive exploration of event preservation in stratigraphy – a prerequisite for reliable environmental reconstructions from terrestrially derived sedimentary records. KW - signal propagation KW - landscape transience KW - source-to-sink KW - stratigraphy KW - response time Y1 - 2021 U6 - https://doi.org/10.3389/feart.2021.628315 SN - 2296-6463 VL - 9 SP - 1 EP - 26 PB - Frontiers Media CY - Lausanne, Schweiz ER - TY - THES A1 - Rodriguez Piceda, Constanza T1 - Thermomechanical state of the southern Central Andes T1 - Thermomechanischer Zustand der südlichen Zentral Anden BT - implications for active deformation patterns in the transition from flat to steep subduction BT - Implikationen für aktive Deformationsmuster beim Übergang von flacher zu steiler Subduktion N2 - The Andes are a ~7000 km long N-S trending mountain range developed along the South American western continental margin. Driven by the subduction of the oceanic Nazca plate beneath the continental South American plate, the formation of the northern and central parts of the orogen is a type case for a non-collisional orogeny. In the southern Central Andes (SCA, 29°S-39°S), the oceanic plate changes the subduction angle between 33°S and 35°S from almost horizontal (< 5° dip) in the north to a steeper angle (~30° dip) in the south. This sector of the Andes also displays remarkable along- and across- strike variations of the tectonic deformation patterns. These include a systematic decrease of topographic elevation, of crustal shortening and foreland and orogenic width, as well as an alternation of the foreland deformation style between thick-skinned and thin-skinned recorded along- and across the strike of the subduction zone. Moreover, the SCA are a very seismically active region. The continental plate is characterized by a relatively shallow seismicity (< 30 km depth) which is mainly focussed at the transition from the orogen to the lowland areas of the foreland and the forearc; in contrast, deeper seismicity occurs below the interiors of the northern foreland. Additionally, frequent seismicity is also recorded in the shallow parts of the oceanic plate and in a sector of the flat slab segment between 31°S and 33°S. The observed spatial heterogeneity in tectonic and seismic deformation in the SCA has been attributed to multiple causes, including variations in sediment thickness, the presence of inherited structures and changes in the subduction angle of the oceanic slab. However, there is no study that inquired the relationship between the long-term rheological configuration of the SCA and the spatial deformation patterns. Moreover, the effects of the density and thickness configuration of the continental plate and of variations in the slab dip angle in the rheological state of the lithosphere have been not thoroughly investigated yet. Since rheology depends on composition, pressure and temperature, a detailed characterization of the compositional, structural and thermal fields of the lithosphere is needed. Therefore, by using multiple geophysical approaches and data sources, I constructed the following 3D models of the SCA lithosphere: (i) a seismically-constrained structural and density model that was tested against the gravity field; (ii) a thermal model integrating the conversion of mantle shear-wave velocities to temperature with steady-state conductive calculations in the uppermost lithosphere (< 50 km depth), validated by temperature and heat-flow measurements; and (iii) a rheological model of the long-term lithospheric strength using as input the previously-generated models. The results of this dissertation indicate that the present-day thermal and rheological fields of the SCA are controlled by different mechanisms at different depths. At shallow depths (< 50 km), the thermomechanical field is modulated by the heterogeneous composition of the continental lithosphere. The overprint of the oceanic slab is detectable where the oceanic plate is shallow (< 85 km depth) and the radiogenic crust is thin, resulting in overall lower temperatures and higher strength compared to regions where the slab is steep and the radiogenic crust is thick. At depths > 50 km, largest temperatures variations occur where the descending slab is detected, which implies that the deep thermal field is mainly affected by the slab dip geometry. The outcomes of this thesis suggests that long-term thermomechanical state of the lithosphere influences the spatial distribution of seismic deformation. Most of the seismicity within the continental plate occurs above the modelled transition from brittle to ductile conditions. Additionally, there is a spatial correlation between the location of these events and the transition from the mechanically strong domains of the forearc and foreland to the weak domain of the orogen. In contrast, seismicity within the oceanic plate is also detected where long-term ductile conditions are expected. I therefore analysed the possible influence of additional mechanisms triggering these earthquakes, including the compaction of sediments in the subduction interface and dehydration reactions in the slab. To that aim, I carried out a qualitative analysis of the state of hydration in the mantle using the ratio between compressional- and shear-wave velocity (vp/vs ratio) from a previous seismic tomography. The results from this analysis indicate that the majority of the seismicity spatially correlates with hydrated areas of the slab and overlying continental mantle, with the exception of the cluster within the flat slab segment. In this region, earthquakes are likely triggered by flexural processes where the slab changes from a flat to a steep subduction angle. First-order variations in the observed tectonic patterns also seem to be influenced by the thermomechanical configuration of the lithosphere. The mechanically strong domains of the forearc and foreland, due to their resistance to deformation, display smaller amounts of shortening than the relatively weak orogenic domain. In addition, the structural and thermomechanical characteristics modelled in this dissertation confirm previous analyses from geodynamic models pointing to the control of the observed heterogeneities in the orogen and foreland deformation style. These characteristics include the lithospheric and crustal thickness, the presence of weak sediments and the variations in gravitational potential energy. Specific conditions occur in the cold and strong northern foreland, which is characterized by active seismicity and thick-skinned structures, although the modelled crustal strength exceeds the typical values of externally-applied tectonic stresses. The additional mechanisms that could explain the strain localization in a region that should resist deformation are: (i) increased tectonic forces coming from the steepening of the slab and (ii) enhanced weakening along inherited structures from pre-Andean deformation events. Finally, the thermomechanical conditions of this sector of the foreland could be a key factor influencing the preservation of the flat subduction angle at these latitudes of the SCA. N2 - Die Anden sind eine ~7000 km lange N-S-verlaufende Hochgebirgskette, die entlang des westlichen südamerikanischen Kontinentalrandes entstanden ist. Aufgrund der Subduktion der ozeanischen Nazca-Platte unter die kontinentale südamerikanische Platte ist die Bildung des nördlichen und zentralen Teils des Gebirges typisch für eine nicht-kollisionale Orogenese. In den südlichen Zentralanden (SZA, 29-39° S) verändert sich der Subduktionswinkel der ozeanischen Platte zwischen 33 ° S und 35 ° S von fast horizontal (< 5° Einfallen) im Norden zu einem steileren Winkel (~ 30 ° Einfallen) im Süden. Begleitet wird dieser Trend von systematischen, Süd-gerichteten Abnahmen der topographischen Erhebung, der Krusteneinengung und der Vorland- und Orogenbreite, sowie von Variationen im Deformationsstil des Vorlandes, wo die Einengung des Deckgebirges in unterschiedlichem Maße von einer entsprechenden Deformation des Grundgebirges begleitet wird. . Darüber hinaus sind die SZA eine seismisch sehr aktive Region. Die Kontinentalplatte zeichnet sich durch eine relativ flache Seismizität (< 30 km Tiefe) aus, die sich hauptsächlich auf die Übergänge vom Orogen zu den Vorlandbereichen konzentriert; im Gegensatz dazu tritt tiefere Seismizität in den zentralen Bereichen des nördlichen Vorlandes auf. Darüber hinaus ist häufig auftretende Seismizität auch in den flachen Teilen der ozeanischen Platte und im Plattensegment mit flach einfallender Subduktion zwischen 31 ° S und 33 ° S festzustellen. Die beobachtete räumliche Heterogenität der tektonischen und seismischen Deformation in den SZA wurde auf mehrere Ursachen zurückgeführt, darunter Schwankungen der Sedimentmächtigkeit, das Vorhandensein vererbter Strukturen und Veränderungen des Subduktionswinkels der ozeanischen Platte. Es gibt jedoch bislang keine Studie, die den Zusammenhang zwischen der langfristigen rheologischen Konfiguration der SZA und den räumlichen Deformationsmustern untersucht hat. Darüber hinaus wurden die Auswirkungen der Dichte- und Mächtigkeitsvariationen in der kontinentalen Oberplatte und der verschiedenen Subduktionswinkel auf den rheologischen Zustand der Lithosphäre noch nicht grundlegend untersucht. Da die Rheologie von der Gesteinsart, dem Druck und der Temperatur abhängt, ist eine detaillierte Charakterisierung der Zusammensetzung, Struktur und des thermischen Feldes der Lithosphäre erforderlich. Daher habe ich unter Verwendung kombinierter Modellierungsansätze und geophysikalischer Daten die folgenden 3D Modelle für die Lithosphäre der SZA konstruiert: (i) ein auf seismischen Daten basierendes Struktur- und Dichtemodell, das anhand des beobachteten Schwerefeldes validiert wurde; (ii) ein thermisches Modell, das die Umwandlung von Mantelscherwellengeschwindigkeiten in Temperaturen mit Berechnungen des konduktiven Wärmetransports für stationäre Bedingungen in der obersten Lithosphäre (<50 km Tiefe) integriert und durch Temperatur- und Wärmeflussmessungen validiert wurde; und (iii) ein rheologisches Modell der langfristig bedingten Lithosphärenfestigkeit, das auf den zuvor erzeugten Modellen gründet. Die Ergebnisse dieser Dissertation zeigen, dass die thermischen und rheologischen Bedingungen in den heutigen SZA durch verschiedene Mechanismen in unterschiedlichen Tiefen gesteuert werden. In flachen Tiefen (< 50 km) wird das thermomechanische Feld durch die heterogene Zusammensetzung der kontinentalen Lithosphäre differenziert. Eine Überprägung durch die ozeanische Platte ist dort nachweisbar, wo die ozeanische Platte flach (< 85 km tief) und die radiogene Kruste dünn ist, was insgesamt zu niedrigeren Temperaturen und einer höheren Festigkeit im Vergleich zu Bereichen führt, in denen die Platte steil einfällt und die radiogene Kruste dick ist. In Tiefen > 50 km treten die größten Temperaturschwankungen dort auf, wo die subduzierten Platte nachgewiesen wurde, was bedeutet, dass das tiefe thermische Feld den Subduktionswinkel gesteuert wird. Die Ergebnisse dieser Doktorarbeit legen nahe, dass der langfristige thermomechanische Zustand der Lithosphäre die räumliche Verteilung rezenter Seismizität beeinflusst. Der größte Anteil innerhalb der Kontinentalplatte registrierter Erdbebentätigkeit tritt oberhalb des modellierten Übergangs von spröden zu duktilen Bedingungen auf. Außerdem besteht eine räumliche Korrelation zwischen Erdbebenclustern und den Übergängen von den mechanisch rigideren Vorlandbereichen (Forearc und Foreland) zum mechanisch schwächeren Orogen. Demgegenüber wird vermehrte Seismizität innerhalb der ozeanischen Platte auch dort nachgewiesen, wo entsprechend der Modellierung langfristig duktile Bedingungen erwartet werden. Ich habe daher den möglichen Einfluss zusätzlicher Mechanismen untersucht, die ein Auslösen dieser Erdbeben begünstigen könnten, darunter die Kompaktion von Sedimenten an der Subduktionsgrenzfläche und Dehydrationsreaktionen innerhalb der Platte. Dazu habe ich eine qualitative Analyse des Hydratationszustandes des Mantels unter Verwendung des Verhältnisses zwischen Kompressions- und Scherwellengeschwindigkeit (Vp/Vs-Verhältnis aus einemseismischen Tomographiemodell) durchgeführt. Die Ergebnisse dieser Analyse zeigen, dass der Großteil der Seismizität räumlich mit hydratisierten Bereichen in der subduzierten Platte und im darüber liegenden kontinentalen Mantel korreliert, mit Ausnahme eines Erdbebenclusters, das innerhalb des flachen Plattensegments auftritt. In diesem Bereich wechselt die subduzierte Platte von einem flachen in einen steilen Subduktionswinkel und Erdbeben werden wahrscheinlich durch Biegevorgänge in der Platte ausgelöst. Auch die wichtigsten Variationen in den beobachteten tektonischen Mustern scheinen durch die thermomechanische Konfiguration der Lithosphäre beeinflusst zu sein. Die mechanisch starken Bereiche von Forearc und Foreland zeigen aufgrund ihrer Verformungsbeständigkeit geringere Verkürzungsraten als der relativ schwache Bereich des Orogens. Darüber hinaus bestätigen die in dieser Dissertation modellierten strukturellen und thermomechanischen Eigenschaften der Lithosphäre auch frühere Analysen geodynamischer Simulationen, denen zufolge der Deformationsstil im Orogen- und Vorlandbereich jeweils von Variationen in der Lithosphären- und Krustendicke, im Vorhandensein schwacher Sedimente und in der gravitativen potentiellen Energie kontrolliert wird. Eine Sonderstellung nimmt der nordöstliche Vorlandbereich der SZA ein, wo eine verstärkte Seismizität und eine das Deck-und Grundgebirge erfassende Deformation zu beobachten sind, obwohl die modellierte Krustenfestigkeit dort Werte übersteigt, die für die in diesem Gebiet anzunehmenden tektonischen Spannungen typisch wären. . Mechanismen zur Lokalisierung verstärkter Deformation in einem Gebiet beitragen können, das nach den vorliegenden Modellen einer tektonischen Verformung widerstehen sollte, sind: (i) erhöhte tektonische Kräfte durch ein steileres Abtauchen der Platte und (ii) Schwächezonen in der Kruste, die auf prä-andine Deformationsereignisse zurückgehen. Schließlich könnten die thermomechanischen Bedingungen in diesem Teil des Vorlands einchlüsselfaktor für die Erhaltung des flachen Subduktionswinkels in diesen Breiten der SZA sein. KW - Andes KW - Anden KW - subduction KW - Subduktion KW - lithosphere KW - Lithosphäre KW - earthquakes KW - Erdbeben KW - modelling KW - Modellierung Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-549275 ER - TY - THES A1 - Lenz, Josefine T1 - Thermokarst dynamics in central-eastern Beringia T1 - Thermokarstdynamik im zentral-östlichen Beringia BT - insights from permafrost and lacustrine sediment cores BT - Einblicke durch Permafrost- und Seesedimentkerne N2 - Widespread landscape changes are presently observed in the Arctic and are most likely to accelerate in the future, in particular in permafrost regions which are sensitive to climate warming. To assess current and future developments, it is crucial to understand past environmental dynamics in these landscapes. Causes and interactions of environmental variability can hardly be resolved by instrumental records covering modern time scales. However, long-term environmental variability is recorded in paleoenvironmental archives. Lake sediments are important archives that allow reconstruction of local limnogeological processes as well as past environmental changes driven directly or indirectly by climate dynamics. This study aims at reconstructing Late Quaternary permafrost and thermokarst dynamics in central-eastern Beringia, the terrestrial land mass connecting Eurasia and North America during glacial sea-level low stands. In order to investigate development, processes and influence of thermokarst dynamics, several sediment cores from extant lakes and drained lake basins were analyzed to answer the following research questions: 1. When did permafrost degradation and thermokarst lake development take place and what were enhancing and inhibiting environmental factors? 2. What are the dominant processes during thermokarst lake development and how are they reflected in proxy records? 3. How did, and still do, thermokarst dynamics contribute to the inventory and properties of organic matter in sediments and the carbon cycle? Methods applied in this study are based upon a multi-proxy approach combining sedimentological, geochemical, geochronological, and micropaleontological analyses, as well as analyses of stable isotopes and hydrochemistry of pore-water and ice. Modern field observations of water quality and basin morphometrics complete the environmental investigations. The investigated sediment cores reveal permafrost degradation and thermokarst dynamics on different time scales. The analysis of a sediment core from GG basin on the northern Seward Peninsula (Alaska) shows prevalent terrestrial accumulation of yedoma throughout the Early to Mid Wisconsin with intermediate wet conditions at around 44.5 to 41.5 ka BP. This first wetland development was terminated by the accumulation of a 1-meter-thick airfall tephra most likely originating from the South Killeak Maar eruption at 42 ka BP. A depositional hiatus between 22.5 and 0.23 ka BP may indicate thermokarst lake formation in the surrounding of the site which forms a yedoma upland till today. The thermokarst lake forming GG basin initiated 230 ± 30 cal a BP and drained in Spring 2005 AD. Four years after drainage the lake talik was still unfrozen below 268 cm depth. A permafrost core from Mama Rhonda basin on the northern Seward Peninsula preserved a full lacustrine record including several lake phases. The first lake generation developed at 11.8 cal ka BP during the Lateglacial-Early Holocene transition; its old basin (Grandma Rhonda) is still partially preserved at the southern margin of the study basin. Around 9.0 cal ka BP a shallow and more dynamic thermokarst lake developed with actively eroding shorelines and potentially intermediate shallow water or wetland phases (Mama Rhonda). Mama Rhonda lake drainage at 1.1 cal ka BP was followed by gradual accumulation of terrestrial peat and top-down refreezing of the lake talik. A significant lower organic carbon content was measured in Grandma Rhonda deposits (mean TOC of 2.5 wt%) than in Mama Rhonda deposits (mean TOC of 7.9 wt%) highlighting the impact of thermokarst dynamics on biogeochemical cycling in different lake generations by thawing and mobilization of organic carbon into the lake system. Proximal and distal sediment cores from Peatball Lake on the Arctic Coastal Plain of Alaska revealed young thermokarst dynamics since about 1,400 years along a depositional gradient based on reconstructions from shoreline expansion rates and absolute dating results. After its initiation as a remnant pond of a previous drained lake basin, a rapidly deepening lake with increasing oxygenation of the water column is evident from laminated sediments, and higher Fe/Ti and Fe/S ratios in the sediment. The sediment record archived characterizing shifts in depositional regimes and sediment sources from upland deposits and re-deposited sediments from drained thaw lake basins depending on the gradually changing shoreline configuration. These changes are evident from alternating organic inputs into the lake system which highlights the potential for thermokarst lakes to recycle old carbon from degrading permafrost deposits of its catchment. The lake sediment record from Herschel Island in the Yukon (Canada) covers the full Holocene period. After its initiation as a thermokarst lake at 11.7 cal ka BP and intense thermokarst activity until 10.0 cal ka BP, the steady sedimentation was interrupted by a depositional hiatus at 1.6 cal ka BP which likely resulted from lake drainage or allochthonous slumping due to collapsing shore lines. The specific setting of the lake on a push moraine composed of marine deposits is reflected in the sedimentary record. Freshening of the maturing lake is indicated by decreasing electrical conductivity in pore-water. Alternation of marine to freshwater ostracods and foraminifera confirms decreasing salinity as well but also reflects episodical re-deposition of allochthonous marine sediments. Based on permafrost and lacustrine sediment records, this thesis shows examples of the Late Quaternary evolution of typical Arctic permafrost landscapes in central-eastern Beringia and the complex interaction of local disturbance processes, regional environmental dynamics and global climate patterns. This study confirms that thermokarst lakes are important agents of organic matter recycling in complex and continuously changing landscapes. N2 - Derzeit werden deutliche Landschaftsveränderungen in der Arktis beobachtet, welche sich höchstwahrscheinlich zukünftig v.a. in den Permafrostregionen verstärken, da diese besonders empfindlich auf Klimaveränderungen reagieren. Um derzeitige und zukünftige Entwicklungen einschätzen zu können, ist es wichtig vergangene Umweltprozesse zu verstehen. Ursachen und Wechselwirkungen von Umweltveränderungen können nur bedingt durch instrumentelle Aufzeichnungen erklärt werden, doch Paleo-Umweltarchive können weit in die Vergangenheit reichende Umweltdynamiken aufzeichnen. Seesedimente sind wichtige Archive, die lokale limnogeologische Prozesse, aber auch direkt oder indirekt klimatisch gesteuerte Umweltveränderungen der Vergangenheit aufzeichnen. Ziel der vorliegenden Arbeit ist es, spätquartäre Permafrost- und Thermokarstdynamik im zentral-östlichen Beringia zu rekonstruieren. Beringia umfasst jene terrestrische Landmasse, welche Eurasien und Nord-Amerika zu Zeiten von Meeresspiegeltiefständen verband. Um die Entwicklung, die Prozesse und den Einfluss von Thermokarstdynamik zu untersuchen, wurden mehrere Sedimentkerne von rezenten Seen und ausgelaufenen Seebecken analysiert, um folgende Forschungsfragen zu beantworten: 1. Zu welcher Zeit degradierte Permafrost und wann entwickelten sich Thermokarstseen? Was waren hemmende oder verstärkende Faktoren? 2. Was sind dominierende Prozesse während der Entwicklung von Thermokarstseen und wie spiegeln sich diese in Proxy-Aufzeichnungen wieder? 3. Wie hat Thermokarstdynamik damals und heute zur Bedeutung von organischer Substanz in Sedimenten und im Kohlenstoffkreislauf beigetragen? Die in dieser Arbeit angewandten Methoden basieren auf einem sogenannten „multi-proxy“ Ansatz, der sedimentologische, geochemische, geochronologische und mikropaläontologische Analysen, sowie die Untersuchung von stabilen Isotopen und die Hydrochemie von Porenwasser und -eis, verbindet. Feldmessungen der modernen Wasserqualität und Beckenmorphometrie komplettieren die Umweltuntersuchungen. Auf Grundlage der untersuchten Sedimentkerne lässt sich die Degradation von Permafrost und die Dynamik von Thermokarst auf zeitlich verschiedenen Skalen rekonstruieren. Die Analyse eines Sedimentkerns vom GG-Becken auf der nördlichen Seward-Halbinsel (Alaska) zeigt eine vorwiegend terrestrische Akkumulation von Yedoma während des Früh- und Mittel-Wisconsin mit zwischenzeitlich feuchteren Verhältnissen zwischen 44,5 und 41,5 ka BP. Diese frühe Feuchtgebietsphase wurde durch die Akkumulation einer 1 m dicken Tephra-Lage beendet, welche sehr wahrscheinlich von der Eruption des heutigen South Killeak Maar vor etwa 42.000 Jahren stammt. Eine Schichtlücke im Sedimentkern von etwa 22,5 und 0,23 ka BP gibt einen Hinweis auf Thermokarstentwicklung in der Umgebung der Kernlokation, welche bis heute ein Yedoma-Rudiment bildet. Der Thermokarstsee, der GG-Becken formte, entstand 230 ± 30 cal a BP und drainierte im Frühling 2005 AD. Vier Jahre nach der Drainage war der Talik des Sees in einer Tiefe von 268 cm noch ungefroren. Ein Permafrostkern vom Mama Rhonda-Becken auf der nördlichen Seward-Halbinsel archivierte eine vollständige limnische Fazies mit mehreren Seephasen. Die erste Seegeneration entstand am Übergang vom Spätglazial zum Frühholozän um etwa 11,8 cal ka BP; das alte Seebecken (Grandma Rhonda) ist bis heute südlich der Kernlokation erhalten. Etwa um 9,0 cal ka BP entwickelte sich ein eher flaches und dynamisches Seesystem mit aktiv erodierenden Ufern und potenziell zwischengeschalteten Flachwasser- oder Feuchtgebietsphasen (Mama Rhonda). Die Drainage vom Mama Rhonda-See etwa 1,1 cal ka BP wurde gefolgt von gradueller Torfakkumulation und einem von oben zurückfrierenden See-Talik Es wurde ein deutlich geringerer organischer Kohlenstoff-Gehalt in Grandma Rhonda-Ablagerungen (TOC im Mittel 2,5 Gew.-%) festgestellt, als in Mama Rhonda Ablagerungen (TOC im Mittel 7,9 Gew.-%). Dies zeigt den bedeutenden Einfluss von Thermokarst auf biogeochemische Kreisläufe, da in verschiedenen Seegenerationen organischen Kohlenstoff durch Permafrost-Tauen im Seesystem mobilisiert wird. Seesedimentkerne aus der Uferzone und dem zentralen Bereich von Peatball Lake auf der Arktischen Küstenebene von Alaska, ergaben eine junge Thermokarstdynamik von 1.400 Jahren, welche auf der Basis von absoluten Datierungen und Uferexpansionsraten rekonstruiert wurde. Nach der Seeinitiierung als Rest-See eines zuvor ausgelaufenen Seebeckens, vertiefte sich Peatball Lake verhältnismäßig schnell mit zunehmender Sauerstoffanreicherung der Wassersäule, wie aus laminierten Sedimenten und hohen Fe/Ti- und Fe/S-Verhältnissen im Sediment ersichtlich ist. Die Sedimente von Peatball Lake archivierten einen Wechsel des Ablagerungsregimes bei Ausdehnung der Seefläche und einen Wechsel der Sedimentquelle von ursprünglichen, rein terrestrischen Ablagerungen und bereits umgelagerten Sedimenten aus drainierten Seebecken. Angezeigt wird dieser Wechsel durch eine Veränderung im Eintrag organischen Materials in das Seesystem, was wiederum das Potential von Thermokarstseen bei der Aufarbeitung alten Kohlenstoffs aus degradierendem Permafrost im Einzugsgebiet verdeutlicht. Der Seesedimentkern von der Herschel Insel im Yukon (Kanada) deckt das gesamte Holozän ab. Nach der Seeentstehung um 11,7 cal ka BP und einer Zeit intensiver Thermokarstaktivität bis 11,0 cal ka BP, wird die Phase einer eher kontinuierlichen Sedimentation von einer Schichtlücke um 1,6 cal ka BP unterbrochen. Diese wurde entweder durch die Drainage des Sees oder einer allochthonen Rutschung instabiler Uferlinien verursacht. Die spezielle Situation des Sees auf einer Stauchendmoräne aus marinem Material spiegelt sich auch in dem Seesedimentarchiv wieder. Das Aussüßen des wachsenden Sees wird durch die abnehmende elektrische Leitfähigkeit im Porenwasser angezeigt. Der Wechsel von marinen und Süßwasserostrakoden- und Foraminiferengemeinschaften bestätigt zum einen die abnehmende Salinität des Sees, aber zeigt zum anderen auch episodische Umlagerung von allochthonem, marinem Sediment. Auf der Grundlange von Permafrost- und Seesedimentkernen zeigt diese Arbeit Beispiele spätquartärer Entwicklungsgeschichte typischer Arktischer Permafrostlandschaften im zentral-östlichen Beringia. Es werden komplexe Zusammenhänge zwischen lokalen Störungsprozessen, regionaler Umweltdynamik und globalen Klimaveränderungen aufgezeigt. Thermokarstseen spielen dabei eine wichtige Rolle im sich kontinuierlich verändernden Landschaftsbild der hohen Breiten und im Stoffkreislauf bei der Aufarbeitung organischer Substanz. KW - paleolimnology KW - permafrost degradation KW - periglacial landscape evolution KW - thermokarst processes KW - carbon cycling KW - central-eastern Beringia KW - Paläolimnologie KW - Permafrostdegradation KW - periglaziale Landschaftsentwicklung KW - Thermokarstprozesse KW - Kohlenstoffkreislauf KW - zentral-östliches Beringia Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-101364 ER - TY - THES A1 - Morgenstern, Anne T1 - Thermokarst and thermal erosion : degradation of Siberian ice-rich permafrost T1 - Thermokarst und Thermoerosion : Degradation von sibirischem eisreichem Permafrost N2 - Current climate warming is affecting arctic regions at a faster rate than the rest of the world. This has profound effects on permafrost that underlies most of the arctic land area. Permafrost thawing can lead to the liberation of considerable amounts of greenhouse gases as well as to significant changes in the geomorphology, hydrology, and ecology of the corresponding landscapes, which may in turn act as a positive feedback to the climate system. Vast areas of the east Siberian lowlands, which are underlain by permafrost of the Yedoma-type Ice Complex, are particularly sensitive to climate warming because of the high ice content of these permafrost deposits. Thermokarst and thermal erosion are two major types of permafrost degradation in periglacial landscapes. The associated landforms are prominent indicators of climate-induced environmental variations on the regional scale. Thermokarst lakes and basins (alasses) as well as thermo-erosional valleys are widely distributed in the coastal lowlands adjacent to the Laptev Sea. This thesis investigates the spatial distribution and morphometric properties of these degradational features to reconstruct their evolutionary conditions during the Holocene and to deduce information on the potential impact of future permafrost degradation under the projected climate warming. The methodological approach is a combination of remote sensing, geoinformation, and field investigations, which integrates analyses on local to regional spatial scales. Thermokarst and thermal erosion have affected the study region to a great extent. In the Ice Complex area of the Lena River Delta, thermokarst basins cover a much larger area than do present thermokarst lakes on Yedoma uplands (20.0 and 2.2 %, respectively), which indicates that the conditions for large-area thermokarst development were more suitable in the past. This is supported by the reconstruction of the development of an individual alas in the Lena River Delta, which reveals a prolonged phase of high thermokarst activity since the Pleistocene/Holocene transition that created a large and deep basin. After the drainage of the primary thermokarst lake during the mid-Holocene, permafrost aggradation and degradation have occurred in parallel and in shorter alternating stages within the alas, resulting in a complex thermokarst landscape. Though more dynamic than during the first phase, late Holocene thermokarst activity in the alas was not capable of degrading large portions of Pleistocene Ice Complex deposits and substantially altering the Yedoma relief. Further thermokarst development in existing alasses is restricted to thin layers of Holocene ice-rich alas sediments, because the Ice Complex deposits underneath the large primary thermokarst lakes have thawed completely and the underlying deposits are ice-poor fluvial sands. Thermokarst processes on undisturbed Yedoma uplands have the highest impact on the alteration of Ice Complex deposits, but will be limited to smaller areal extents in the future because of the reduced availability of large undisturbed upland surfaces with poor drainage. On Kurungnakh Island in the central Lena River Delta, the area of Yedoma uplands available for future thermokarst development amounts to only 33.7 %. The increasing proximity of newly developing thermokarst lakes on Yedoma uplands to existing degradational features and other topographic lows decreases the possibility for thermokarst lakes to reach large sizes before drainage occurs. Drainage of thermokarst lakes due to thermal erosion is common in the study region, but thermo-erosional valleys also provide water to thermokarst lakes and alasses. Besides these direct hydrological interactions between thermokarst and thermal erosion on the local scale, an interdependence between both processes exists on the regional scale. A regional analysis of extensive networks of thermo-erosional valleys in three lowland regions of the Laptev Sea with a total study area of 5,800 km² found that these features are more common in areas with higher slopes and relief gradients, whereas thermokarst development is more pronounced in flat lowlands with lower relief gradients. The combined results of this thesis highlight the need for comprehensive analyses of both, thermokarst and thermal erosion, in order to assess past and future impacts and feedbacks of the degradation of ice-rich permafrost on hydrology and climate of a certain region. N2 - Die gegenwärtige Klimaerwärmung wirkt sich auf arktische Regionen stärker aus als auf andere Gebiete der Erde. Das hat weitreichende Konsequenzen für Permafrost, der weite Teile der terrestrischen Arktis unterlagert. Das Tauen von Permafrost kann zur Freisetzung erheblicher Mengen an Treibhausgasen sowie zu gravierenden Änderungen in der Geomorphologie, Hydrologie und Ökologie betroffener Landschaften führen, was wiederum als positive Rückkopplung auf das Klimasystem wirken kann. Ausgedehnte Gebiete der ostsibirischen Tiefländer, die mit Permafrost des Yedoma Eiskomplex unterlagert sind, gelten aufgrund des hohen Eisgehalts dieser Permafrostablagerungen als besonders empfindlich gegenüber Klimaerwärmungen. Thermokarst und Thermoerosion sind zwei Hauptformen der Permafrostdegradation in periglazialen Landschaften. Die zugehörigen Landschaftsformen sind auf der regionalen Skala bedeutende Indikatoren klimainduzierter Umweltvariationen. Thermokarstseen und senken (Alasse) sowie Thermoerosionstäler sind in den Küstentiefländern der Laptewsee weit verbreitet. Die vorliegende Dissertation untersucht die räumliche Verbreitung und die morphometrischen Eigenschaften dieser Degradationsformen mit dem Ziel, ihre Entwicklungsbedingungen während des Holozäns zu rekonstruieren und Hinweise auf potenzielle Auswirkungen zukünftiger Permafrostdegradation im Zuge der erwarteten Klimaerwärmung abzuleiten. Der methodische Ansatz ist eine Kombination aus Fernerkundungs-, Geoinformations- und Geländeuntersuchungen, die Analysen auf lokalen bis regionalen räumlichen Skalen integriert. Thermokarst und Thermoerosion haben die Untersuchungsregion tiefgreifend geprägt. Im Eiskomplexgebiet des Lena-Deltas nehmen Thermokarstsenken eine weitaus größere Fläche ein als Thermokarstseen auf Yedoma-Hochflächen (20,0 bzw. 2,2 %), was darauf hin deutet, dass die Bedingungen für die Entwicklung von großflächigem Thermokarst in der Vergangenheit wesentlich günstiger waren als heute. Die Rekonstruktion der Entwicklung eines einzelnen Alas im Lena-Delta belegt eine andauernde Phase hoher Thermokarstaktivität seit dem Übergang vom Pleistozän zum Holozän, die zur Entstehung einer großen und tiefen Senke führte. Nach der Drainage des primären Thermokarstsees im mittleren Holozän erfolgten Permafrostaggradation und degradation parallel und in kürzeren abwechselnden Etappen innerhalb des Alas und führten zu einer komplexen Thermokarstlandschaft. Trotzdem die spätholozäne Thermokarstentwicklung im Alas dynamischer ablief als die erste Entwicklungsphase, resultierte sie nicht in der Degradation großer Teile pleistozäner Eiskomplexablagerungen und einer wesentlichen Veränderung des Yedoma-Reliefs. Weitere Thermokarstentwicklung in bestehenden Alassen ist begrenzt auf geringmächtige Lagen holozäner eisreicher Alas-Sedimente, da die Eiskomplexablagerungen unter den großen primären Thermokarstseen vollständig getaut waren und die unterlagernden Sedimente aus eisarmen, fluvialen Sanden bestehen. Thermokarstprozesse auf ungestörten Yedoma-Hochflächen wirken am stärksten verändernd auf Eiskomplexablagerungen, werden aber in Zukunft auf geringere Ausmaße begrenzt sein, da die Verfügbarkeit großer ungestörter, schwach drainierter Yedoma-Hochflächen abnimmt. Auf der Insel Kurungnakh im zentralen Lena-Delta beträgt der für zukünftige Thermokarstentwicklung verfügbare Anteil an Yedoma-Hochflächen nur 33,7 %. Die zunehmende Nähe von sich entwickelnden Thermokarstseen auf Yedoma-Hochflächen zu bestehenden Degradationsstrukturen und anderen negativen Reliefformen verringert die Möglichkeit der Thermokarstseen, große Ausmaße zu erreichen bevor sie drainieren. Die Drainage von Thermokarstseen durch Thermoerosion ist in der Untersuchungsregion weit verbreitet, aber Thermoerosionstäler versorgen Thermokarstseen und –senken auch mit Wasser. Neben diesen direkten hydrologischen Wechselwirkungen zwischen Thermokarst und Thermoerosion auf der lokalen Ebene existiert auch eine Interdependenz zwischen beiden Prozessen auf der regionalen Ebene. Eine regionale Analyse weitreichender Netze von Thermoerosionstälern in drei Tieflandgebieten der Laptewsee mit einer Fläche von insgesamt 5800 km² zeigte, dass diese Formen häufiger in Gebieten mit höheren Geländeneigungen und Reliefgradienten auftreten, während Thermokarstentwicklung stärker in flachen Tiefländern mit geringeren Reliefgradienten ausgeprägt ist. Die kombinierten Ergebnisse dieser Dissertation zeigen die Notwendigkeit von umfassenden Analysen beider Prozesse und Landschaftsformen, Thermokarst und Thermoerosion, im Hinblick auf die Abschätzung vergangener und zukünftiger Auswirkungen der Degradation eisreichen Permafrosts auf Hydrologie und Klima der betrachteten Region und deren Rückkopplungen. KW - Fernerkundung KW - GIS KW - räumliche Analyse KW - periglaziale Landschaften KW - Arktis KW - remote sensing KW - GIS KW - spatial analyses KW - periglacial landscapes KW - Arctic Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-62079 ER - TY - THES A1 - Meeßen, Christian T1 - The thermal and rheological state of the Northern Argentinian foreland basins T1 - Der thermische und rheologische Zustand der Nordargentinischen Vorlandbecken N2 - The foreland of the Andes in South America is characterised by distinct along strike changes in surface deformational styles. These styles are classified into two end-members, the thin-skinned and the thick-skinned style. The superficial expression of thin-skinned deformation is a succession of narrowly spaced hills and valleys, that form laterally continuous ranges on the foreland facing side of the orogen. Each of the hills is defined by a reverse fault that roots in a basal décollement surface within the sedimentary cover, and acted as thrusting ramp to stack the sedimentary pile. Thick-skinned deformation is morphologically characterised by spatially disparate, basement-cored mountain ranges. These mountain ranges are uplifted along reactivated high-angle crustal-scale discontinuities, such as suture zones between different tectonic terranes. Amongst proposed causes for the observed variation are variations in the dip angle of the Nazca plate, variation in sediment thickness, lithospheric thickening, volcanism or compositional differences. The proposed mechanisms are predominantly based on geological observations or numerical thermomechanical modelling, but there has been no attempt to understand the mechanisms from a point of data-integrative 3D modelling. The aim of this dissertation is therefore to understand how lithospheric structure controls the deformational behaviour. The integration of independent data into a consistent model of the lithosphere allows to obtain additional evidence that helps to understand the causes for the different deformational styles. Northern Argentina encompasses the transition from the thin-skinned fold-and-thrust belt in Bolivia, to the thick-skinned Sierras Pampeanas province, which makes this area a well suited location for such a study. The general workflow followed in this study first involves data-constrained structural- and density-modelling in order to obtain a model of the study area. This model was then used to predict the steady-state thermal field, which was then used to assess the present-day rheological state in northern Argentina. The structural configuration of the lithosphere in northern Argentina was determined by means of data-integrative, 3D density modelling verified by Bouguer gravity. The model delineates the first-order density contrasts in the lithosphere in the uppermost 200 km, and discriminates bodies for the sediments, the crystalline crust, the lithospheric mantle and the subducting Nazca plate. To obtain the intra-crustal density structure, an automated inversion approach was developed and applied to a starting structural model that assumed a homogeneously dense crust. The resulting final structural model indicates that the crustal structure can be represented by an upper crust with a density of 2800 kg/m³, and a lower crust of 3100 kg/m³. The Transbrazilian Lineament, which separates the Pampia terrane from the Río de la Plata craton, is expressed as a zone of low average crustal densities. In an excursion, we demonstrate in another study, that the gravity inversion method developed to obtain intra-crustal density structures, is also applicable to obtain density variations in the uppermost lithospheric mantle. Densities in such sub-crustal depths are difficult to constrain from seismic tomographic models due to smearing of crustal velocities. With the application to the uppermost lithospheric mantle in the north Atlantic, we demonstrate in Tan et al. (2018) that lateral density trends of at least 125\,km width are robustly recovered by the inversion method, thereby providing an important tool for the delineation of subcrustal density trends. Due to the genetic link between subduction, orogenesis and retroarc foreland basins the question rises whether the steady-state assumption is valid in such a dynamic setting. To answer this question, I analysed (i) the impact of subduction on the conductive thermal field of the overlying continental plate, (ii) the differences between the transient and steady-state thermal fields of a geodynamic coupled model. Both studies indicate that the assumption of a thermal steady-state is applicable in most parts of the study area. Within the orogenic wedge, where the assumption cannot be applied, I estimated the transient thermal field based on the results of the conducted analyses. Accordingly, the structural model that had been obtained in the first step, could be used to obtain a 3D conductive steady-state thermal field. The rheological assessment based on this thermal field indicates that the lithosphere of the thin-skinned Subandean ranges is characterised by a relatively strong crust and a weak mantle. Contrarily, the adjacent foreland basin consists of a fully coupled, very strong lithosphere. Thus, shortening in northern Argentina can only be accommodated within the weak lithosphere of the orogen and the Subandean ranges. The analysis suggests that the décollements of the fold-and-thrust belt are the shallow continuation of shear zones that reside in the ductile sections of the orogenic crust. Furthermore, the localisation of the faults that provide strain transfer between the deeper ductile crust and the shallower décollement is strongly influenced by crustal weak zones such as foliation. In contrast to the northern foreland, the lithosphere of the thick-skinned Sierras Pampeanas is fully coupled and characterised by a strong crust and mantle. The high overall strength prevents the generation of crustal-scale faults by tectonic stresses. Even inherited crustal-scale discontinuities, such as sutures, cannot sufficiently reduce the strength of the lithosphere in order to be reactivated. Therefore, magmatism that had been identified to be a precursor of basement uplift in the Sierras Pampeanas, is the key factor that leads to the broken foreland of this province. Due to thermal weakening, and potentially lubrication of the inherited discontinuities, the lithosphere is locally weakened such that tectonic stresses can uplift the basement blocks. This hypothesis explains both the spatially disparate character of the broken foreland, as well as the observed temporal delay between volcanism and basement block uplift. This dissertation provides for the first time a data-driven 3D model that is consistent with geophysical data and geological observations, and that is able to causally link the thermo-rheological structure of the lithosphere to the observed variation of surface deformation styles in the retroarc foreland of northern Argentina. N2 - Das Vorland der südamerikanischen Anden ist durch lateral variierende Deformationsregimes des östlichen Vorlands geprägt. Dabei treten zwei grundlegend verschiedene Endglieder mit charakteristischer Architektur auf: flach abgescherte Falten- und Überschiebungsgürtel einerseits und Vorland-Sockelüberschiebungen ("zerbrochenes Vorland") andererseits. Das morphologische Erscheinungsbild der Falten- und Überschiebungsgürtel entspricht lateral ausgedehnten, dicht aneinander gereihten Abfolgen von Hügeln und Tälern. Die Hügel werden durch eine darunter liegende Überschiebung definiert, die in einem subhorizontalen Abscherhorizont in 10 bis 20 km Tiefe endet. Sockelüberschiebungen hingegen sind in Gebieten mit geringer Sedimentmächtigkeit zu finden und sind durch weit auseinander liegende Erhebungen charakterisiert, welche von steil einfallenden, reaktivierten krustenskaligen Verwerfungen begrenzt werden. Als Ursachen der beobachteten Deformationsvariationen wurden präexistente Schwächezonen, Sedimentmächtigkeiten, Lithosphärenverdickung, Vulkanismus oder kompositionelle Eigenschaften aufgeführt. Diese Vorschläge waren überwiegend konzeptuell und meist auf Grundlage von Feldbeobachtungen oder synthetischen numerischen, thermo-mechanischen Modelle abgeleitet. Die vorliegende Dissertation beleuchtet zum ersten mal die Ursachen der beobachteten Deformationsstile aus der Perspektive von dreidimensionaler, Daten-integrativer Modellierung. Durch die Integration voneinander unabhängiger Daten erlaubt diese Art der Beschreibung des physikalischen Zustands der Lithosphäre die Erlangung zusätzliche Hinweise auf die zugrundeliegenden Ursachen der verschiedenen Derformationsregimes. Für eine solche Studie bietet sich Nord-Argentinien an, da dort beide Vorland-Endglieder vorzufinden sind. Die dafür im wesentlichen durchgeführten Arbeitsschritte beinhalten die Erstellung eines strukturellen Dichtemodells des Untersuchungsgebiets, die Berechnung des 3D stationären thermischen Feldes, sowie die Analyse der rheologischen Eigenschaften der Lithosphäre. Das datenbasierte strukturelle Dichtemodell ist mit verschiedenen geologischen und geophysikalischen Beobachtungen sowie dem Bouguer-Schwerefeld konsistent. Dieses Modell bildet die primären Dichtekontraste der oberen 200 km der Lithosphäre ab und differenziert Körper für die Sedimente, die kristalline Kruste, den lithosphärischen Mantel, und die subduzierende Nazca-Platte. Um die krusteninterne Dichteverteilung zu erhalten wurde ein automatisierter Inversionsprozess entworfen der es erlaubt eine leichtere Oberkruste und eine schwerere Unterkruste geometrisch zu definieren. Die Modellierung zeigt, dass die Kruste in Nord-Argentinien durch eine leichtere Oberkruste (2800 kg/m³) und eine dichtere Unterkruste (3100 kg/m³) repräsentiert werden kann. Das Transbrasilianische Linement, welches das Pampia Terran im Westen vom Río de La Plata Kraton im Osten trennt, ist durch eine im Vergleich zur Umgebung geringere durchschnittliche Krustendichte charakterisiert. In einem Exkurs wird anschließend demonstriert, dass die hier entwickelte Inversionsmethodik zur Ermittlung von intrakrustalen Dichtekontrasten auch im obersten lithosphärischen Mantel angewandt werden kann. Dichten zwischen der Kruste-Mantel-Grenze und etwa 50\,km Tiefe sind besonders schwer zu bestimmen, da tomographische Modelle die Geschwindigkeitsvariationen von seismischen Wellen in diesen Bereichen nicht auflösen. In Tan u.a. (2018) demonstrieren wir, dass die Inversionsmethode Dichteverläufe mit einer lateralen Ausdehnung von 125 km oder weniger ermitteln kann, und somit einen wichtigen Beitrag zur Bestimmung von subkrustalen Dichteverteilungen im Mantel liefert. Wegen der genetischen Verbindung zwischen Subduktion, Orogenese und Retroarc Vorlandbecken stellt sich die Frage, ob die Annahme eines stationären thermischen Feldes für solch ein dynamisches Modelliergebiet zulässig ist. Um diese Frage zu beantworten wurde zum einen der Einfluss von Subduktion auf das konduktive thermische Feld auf die kontinentale Lithosphäre untersucht. Zum anderen wurde die Abweichung zwischen transientem und stationären thermischen Feld eines gekoppelten geodynamischen Modells untersucht. Beide Untersuchungen weisen darauf hin, dass die Annahme eines stationären thermischen Felds für den Großteil des Modelliergebiets zulässig ist. Im orogenen Keil, in dem diese Annahme nicht gilt, wurde das transiente thermische Feld mithilfe der erfolgten Untersuchungen abgeschätzt. Entsprechend kann für das Arbeitsgebiet im Vorland das strukturelle Modell aus dem ersten Schritt zur Berechnung des stationären 3D konduktiven thermischen Feldes herangezogen werden. Basierend auf der ermittelten Dichte- und Temperatur-Konfigurationen konnte anschließend die rheologische Konfiguration berechnet werden. Die rheologischen Analysen zeigen, dass die Lithosphäre in Falten- und Überschiebungsgürteln nur eine gerine Festigkeit besitzt und die Kruste Großteil zur integrierten Festigkeit beiträgt. Das benachbarte Vorlandbecken jedoch weist eine vollständig gekoppelte und starke Lithosphäre auf, weshalb Krustenverkürzung nur im vergleichsweise schwachen orogenen Keil aufgenommen werden kann. Daher komme ich zu der Schlussfolgerung, dass die Abscherhorizonte der Falten- und Überschiebungsgürtel die oberflächennahe Fortsetzung von Scherzonen in der duktilen Kruste unterhalb des Orogens sind. Die Lokalisation der Transferzonen zwischen der duktilen Kruste und dem Abscherhorizont sind dabei maßgeblich durch präexistente Schwächezonen in der Kruste beeinflusst. Im zerbrochenen Vorland der Sierras Pampeanas ist die Lithosphäre vollständig gekoppelt und durch einen Mantel hoher Festigkeit charakterisiert. Die sehr hohe integrierte lithosphärische Festigkeit des zerbrochenen Vorlands verhindert die Bildung von Störungen durch tektonische Kräfte. Selbst krustenskalige Schwächezonen können die Festigkeit nicht ausreichend reduzieren, weshalb eine thermische Schwächung benötigt wird. Daher spielt der Magmatismus, der in direkter Nachbarschaft zu den Schwächezonen in der Sierras Pampeanas nachgewiesen wurde, eine Schlüsselrolle in der Entstehung des zerbrochenen Vorlands. Diese Hypothese erklärt die große räumliche Distanz zwischen den Vorlandsockelüberschiebungen, sowie die beobachtete zeitliche Verzögerung zwischen Magmatismus und Hebung der Gebirgskämme. Die vorliegende Studie kann somit aufgrund Daten-integrativer Modellierung einen kausalen Zusammenhang zwischen der Lithosphärenstruktur, den beobachteten Deformationsmechanismen und unabhängigen geologischen Beobachtungen herstellen. KW - Argentina KW - Rheology KW - Foreland basin KW - Foreland basins KW - Density modelling KW - Chaco-Paraná basin KW - Andes KW - Argentinien KW - Rheologie KW - Vorlandbecken KW - Dichtemodellierung KW - Chaco-Paraná Becken KW - Anden Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-439945 ER - TY - JOUR A1 - Mawa, Michael T1 - The Sustainability Mechanisms for Higher Education Quality Assurance Training in Uganda JF - Potsdamer Beiträge zur Hochschulforschung N2 - The paper investigates the question of sustainability of capacity building initiatives by reporting about the multiplication training in the frame of DIES NMT Programme on quality assurance in Uganda and how it could make use of the social capital within the existing quality assurance network to sustain and address challenges during its implementation. The purpose of the article is to explore the nature of networking (social and institutional) which was established by the Ugandan Universities Quality Assurance Forum (UUQAF) and share the strategies used in this training experience for future sustainable capacity building training initiatives in emerging economies. The paper employed a qualitative research method to describe and analyse the training framework based on primary and secondary documents. KW - social network KW - social capital KW - quality assurance KW - training for sustainability KW - benchmarking Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-493931 SN - 978-3-86956-496-8 SN - 2192-1075 SN - 2192-1083 IS - 5 SP - 205 EP - 223 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Elbourne, Paul T1 - The Semantics of Ellipsis JF - Interdisciplinary studies on information structure : ISIS ; working papers of the SFB 632 N2 - There are four phenomena that are particularly troublesome for theories of ellipsis: the existence of sloppy readings when the relevant pronouns cannot possibly be bound; an ellipsis being resolved in such a way that an ellipsis site in the antecedent is not understood in the way it was there; an ellipsis site drawing material from two or more separate antecedents; and ellipsis with no linguistic antecedent. These cases are accounted for by means of a new theory that involves copying syntactically incomplete antecedent material and an analysis of silent VPs and NPs that makes them into higher order definite descriptions that can be bound into. KW - VP-ellipsis KW - NP-deletion KW - definite descriptions Y1 - 2005 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-8722 SN - 1866-4725 SN - 1614-4708 IS - 3 SP - 63 EP - 109 ER - TY - THES A1 - Paganini, Claudio Francesco T1 - The role of trapping in black hole spacetimes T1 - Über die Rolle gefangener lichtartiger Kurven in Raumzeiten mit Schwarzen Löchern N2 - In the here presented work we discuss a series of results that are all in one way or another connected to the phenomenon of trapping in black hole spacetimes. First we present a comprehensive review of the Kerr-Newman-Taub-NUT-de-Sitter family of black hole spacetimes and their most important properties. From there we go into a detailed analysis of the bahaviour of null geodesics in the exterior region of a sub-extremal Kerr spacetime. We show that most well known fundamental properties of null geodesics can be represented in one plot. In particular, one can see immediately that the ergoregion and trapping are separated in phase space. We then consider the sets of future/past trapped null geodesics in the exterior region of a sub-extremal Kerr-Newman-Taub-NUT spacetime. We show that from the point of view of any timelike observer outside of such a black hole, trapping can be understood as two smooth sets of spacelike directions on the celestial sphere of the observer. Therefore the topological structure of the trapped set on the celestial sphere of any observer is identical to that in Schwarzschild. We discuss how this is relevant to the black hole stability problem. In a further development of these observations we introduce the notion of what it means for the shadow of two observers to be degenerate. We show that, away from the axis of symmetry, no continuous degeneration exists between the shadows of observers at any point in the exterior region of any Kerr-Newman black hole spacetime of unit mass. Therefore, except possibly for discrete changes, an observer can, by measuring the black holes shadow, determine the angular momentum and the charge of the black hole under observation, as well as the observer's radial position and angle of elevation above the equatorial plane. Furthermore, his/her relative velocity compared to a standard observer can also be measured. On the other hand, the black hole shadow does not allow for a full parameter resolution in the case of a Kerr-Newman-Taub-NUT black hole, as a continuous degeneration relating specific angular momentum, electric charge, NUT charge and elevation angle exists in this case. We then use the celestial sphere to show that trapping is a generic feature of any black hole spacetime. In the last chapter we then prove a generalization of the mode stability result of Whiting (1989) for the Teukolsky equation for the case of real frequencies. The main result of the last chapter states that a separated solution of the Teukolsky equation governing massless test fields on the Kerr spacetime, which is purely outgoing at infinity, and purely ingoing at the horizon, must vanish. This has the consequence, that for real frequencies, there are linearly independent fundamental solutions of the radial Teukolsky equation which are purely ingoing at the horizon, and purely outgoing at infinity, respectively. This fact yields a representation formula for solutions of the inhomogenous Teukolsky equation, and was recently used by Shlapentokh-Rothman (2015) for the scalar wave equation. N2 - In Newtons Gravitationstheorie bewegt sich Licht auf geraden Linien durch den Raum. Entsprechend beeinflussen Massen den Verlauf von Lichtstrahlen nicht. In Einsteins Allgemeiner Relativitätstheorie führt die Präsenz von Massen dazu, dass sich die Raumzeit, sprich das Koordinatensystem für alle physikalischen Vorgänge, verkrümmt. Da das Licht immer den kürzesten Weg nimmt, wird es nun auch abgelenkt wenn es nahe an einem Körper mit grosser Masse vorbeikommt. Der Nachweis der Lichtablenkung durch die Masse der Sonne bei einer Sonnenfinsternis durch Eddington 1919 war der erste direkte Nachweis, dass Einstein mit seiner Allgemeinen Relativitätstheorie richtig liegt. Eine der erstaunlichsten Vorhersagen aus Einsteins Relativitätstheorie ist die Existenz von Schwarzen Löchern. Es wird gemeinhin angenommen, dass Schwarzen Löcher die dichtesten Objekte sind, welche im Universum existieren können. Ein Schwarzes Loch ist eine Raumzeit, die so stark verkrümmt ist, dass ein Bereich existiert aus welchem nicht einmal mehr Licht entfliehen kann. Die Grenze dieses Bereiches bezeichnet man als Ereignishorizont. Beobachter, welche den Ereignishorizont überqueren, können danach nicht mehr mit Beobachtern ausserhalb kommunizieren. Die Krümmung der Raumzeit in der Nähe des Ereignishorizontes ist so stark, dass sehr gewisse Lichtstrahlen, ähnlich der Planeten im Sonnensystem, auf Kreisbahnen bewegen. Das heisst, dass das Licht weder ins Schwarze Loch fällt, noch ins unendliche davon läuft. Die Bahn solcher Lichtstrahlen bezeichnet man als gefangene lichtartige Kurven. Solche Kurven existieren nur in einem beschränkten Bereich in der Nähe des Ereignishorizontes. Allerdings ist es an jedem Ort der Raumzeit möglich, lichtartige Kurven durch diesen Punkt zu finden, welche sich in der Zukunft einer gefangenen lichtartigen Kurve beliebig annähern und weder ins Schwarze Loch fallen noch ins unendliche davon laufen. Die Gesamtheit aller möglichen Lichtstrahlen durch einen Punkt kann durch eine Kugel, der Himmelssphäre des Beobachters, bestehend aus allen möglichen Raumrichtungen beschrieben werden. In unserer Arbeit zeigen wir, dass die Strahlen, welche sich in der Zukunft einer gefangenen lichtartigen Kurve annähern, die Himmelssphäre in zwei Bereiche unterteilt. Der eine Teil besteht aus jenen Richtungen, in welche der Lichtstrahl im Schwarzen Loch endet, der andere Teil aus jenen Richtungen in welche der Lichtstrahl ins unendliche davon läuft. Die Richtungen in welcher sich die Lichtstrahlen in der Zukunft einer gefangenen lichtartigen Kurve annähern bilden eine geschlossene Kurve auf der Himmelssphäre. Diese Kurve, zusammen mit den Richtungen unter welchen das Licht im Schwarzen Loch endet, bilden den Schatten des Schwarzen Loches auf der Himmelssphäre des Beobachters. Wir konnten zeigen, dass die Form dieses Schattens Rückschlüsse auf die physikalischen Parameter, wie Ladung und Drehmoment des Schwarzen Loches, sowie die Distanz zwischen Beobachter und Schwarzem Loch zulässt. Ausserdem haben wir gezeigt, dass für masselose Felder (Skalarfelder, elektromagnetische Felder, linearisierte Gravitation) auf Raumzeiten mit einem rotierenden Schwarzen Loch, die sogenannte Modenstabillität gilt. Modenlösungen für partielle Differentialgleichungen sind Lösungen, welche ein Produkt von Lösungen in einzelner Koordinatenrichtungen sind. Modenstäbilität bedeutet nun, dass es zu diesen Feldgleichungen, auf diesen Raumzeiten keine Modenlösungen mit realen Frequenzen gibt, welche nur Energie aus der Raumzeit hinaustragen. KW - black hole KW - trapping KW - black hole shadows KW - Teukolsky master equation KW - mode stability KW - Schwarzes Loch KW - gefangene lichtartige Kurven KW - Schatten eines Schwarzen Lochs KW - Teukolsky Gleichung KW - Moden Stabilität Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-414686 ER - TY - JOUR A1 - Dordevic, Milos A1 - Hölzer, Sonja A1 - Russo, Augusta A1 - García Alanis, José Carlos A1 - Müller, Notger Germar T1 - The Role of the Precuneus in Human Spatial Updating in a Real Environment Setting—A cTBS Study JF - Life N2 - As we move through an environment, we update positions of our body relative to other objects, even when some objects temporarily or permanently leave our field of view—this ability is termed egocentric spatial updating and plays an important role in everyday life. Still, our knowledge about its representation in the brain is still scarce, with previous studies using virtual movements in virtual environments or patients with brain lesions suggesting that the precuneus might play an important role. However, whether this assumption is also true when healthy humans move in real environments where full body-based cues are available in addition to the visual cues typically used in many VR studies is unclear. Therefore, in this study we investigated the role of the precuneus in egocentric spatial updating in a real environment setting in 20 healthy young participants who underwent two conditions in a cross-over design: (a) stimulation, achieved through applying continuous theta-burst stimulation (cTBS) to inhibit the precuneus and (b) sham condition (activated coil turned upside down). In both conditions, participants had to walk back with blindfolded eyes to objects they had previously memorized while walking with open eyes. Simplified trials (without spatial updating) were used as control condition, to make sure the participants were not affected by factors such as walking blindfolded, vestibular or working memory deficits. A significant interaction was found, with participants performing better in the sham condition compared to real stimulation, showing smaller errors both in distance and angle. The results of our study reveal evidence of an important role of the precuneus in a real-environment egocentric spatial updating; studies on larger samples are necessary to confirm and further investigate this finding. KW - precuneus KW - spatial updating KW - TMS KW - cTBS Y1 - 2022 U6 - https://doi.org/10.3390/life12081239 SN - 2075-1729 VL - 12 SP - 1 EP - 13 PB - MDPI CY - Basel, Schweiz ET - 8 ER - TY - JOUR A1 - Tiedemann, Kim A1 - Iobbi-Nivol, Chantal A1 - Leimkühler, Silke T1 - The Role of the Nucleotides in the Insertion of the bis-Molybdopterin Guanine Dinucleotide Cofactor into apo-Molybdoenzymes JF - Molecules N2 - The role of the GMP nucleotides of the bis-molybdopterin guanine dinucleotide (bis-MGD) cofactor of the DMSO reductase family has long been a subject of discussion. The recent characterization of the bis-molybdopterin (bis-Mo-MPT) cofactor present in the E. coli YdhV protein, which differs from bis-MGD solely by the absence of the nucleotides, now enables studying the role of the nucleotides of bis-MGD and bis-MPT cofactors in Moco insertion and the activity of molybdoenzymes in direct comparison. Using the well-known E. coli TMAO reductase TorA as a model enzyme for cofactor insertion, we were able to show that the GMP nucleotides of bis-MGD are crucial for the insertion of the bis-MGD cofactor into apo-TorA. KW - bis-MGD KW - chaperone KW - molybdenum cofactor KW - TMAO reductase Y1 - 2022 U6 - https://doi.org/10.3390/molecules27092993 SN - 1420-3049 VL - 27 SP - 1 EP - 15 PB - MDPI CY - Basel, Schweiz ET - 9 ER - TY - THES A1 - Radloff, Katrin T1 - The role of the fatty acid profile and its modulation by cytokines in the systemic inflammation in cancer cachexia T1 - O papel e a modulação do perfil de ácidos graxos por citocinas na inflamação da caquexia associada ao câncer T1 - Die Rolle des Fettsäure-Profils und dessen entzündungsbedingten Veränderungen in der Tumorkachexie N2 - Systemic inflammation is a hallmark of cancer cachexia. Among tumor-host interactions, the white adipose tissue (WAT) is an important contributor to inflammation as it suffers morphological reorganization and lipolysis, releasing free fatty acids (FA), bioactive lipid mediators (LM) and pro-inflammatory cytokines, which accentuate the activation of pro-inflammatory signaling pathways and the recruitment of immune cells to the tissue. This project aimed to investigate which inflammatory factors are involved in the local adipose tissue inflammation and what is the influence of such factors upon enzymes involved in FA or LM metabolism in healthy individuals (Control), weight stable gastro-intestinal cancer patients (WSC) and cachectic cancer patients (CC). The results demonstrated that the inflammatory signature of systemic inflammation is different from local adipose tissue inflammation. The systemic inflammation of the cachectic cancer patients was characterized by higher levels of circulating saturated fatty acids (SFA), tumor-necrosis-factor-α (TNF-α), interleukins IL-6, IL-8 and CRP while levels of polyunsaturated fatty acids (PUFAs), especially n3-PUFAs, were lower in CC than in the other groups. In vitro and in adipose tissue explants, pro-inflammatory cytokines and SFAs were shown to increase the chemokines IL-8 and CXCL10 that were found to be augmented in adipose tissue inflammation in CC which was more profound in the visceral adipose tissue (VAT) than in subcutaneous adipose tissue (SAT). Systemic inflammation was negatively associated with the expression of PUFA synthesizing enzymes, though gene and protein expression did hardly differ between groups. The effects of inflammatory factors on enzymes in the whole tissue could have been masked by differentiated modulation of the diverse cell types in the same tissue. In vitro experiments showed that the expression of FA-modifying enzymes such as desaturases and elongases in adipocytes and macrophages was regulated into opposing directions by TNF-α, IL-6, LPS or palmitate. The higher plasma concentration of the pro-resolving LM resolvin D1 in CC cannot compensate the overall inflammatory status and the results indicate that inflammatory cytokines interfere with synthesis pathways of pro-resolving LM. In summary, the data revealed a complex inter-tissue and inter-cellular crosstalk mediated by pro-inflammatory cytokines and lipid compounds enhancing inflammation in cancer cachexia by feed-forward mechanisms. N2 - Systemische Entzündung ist ein grundlegendes Merkmal der Tumorkachexie. Bei den entzündungstreibenden Wechselwirkungen zwischen Tumor und Wirt spielt das weiße Fettgewebe eine besondere Rolle, da es, bedingt durch morphologische Veränderungen und Lipolyse, freie Fettsäuren, bioaktive Lipidmediatoren (LM) und pro-inflammatorische Cytokine freisetzt. Diese verschiedenen Substanzen verstärken die Aktivierung entzündungsfördernder Signalwege und eine Rekrutierung von Immunzellen in das Gewebe. Das Ziel dieser Arbeit war es daher zu untersuchen, welche Faktoren an der Entwicklung der lokalen Fettgewebsentzündung beteiligt sind und wie diese Faktoren Syntheseenzyme von Fettsäuren und Lipidmediatoren beeinflussen könnten. Dazu wurden Plasma und Fettgewebeproben von gesunden Kontrollpersonen (Control) und normalgewichtigen (WSC) sowie kachektischen Magen-Darm-Krebs-Patienten (CC) untersucht. Die Ergebnisse zeigten, dass sich die inflammatorischen Charakteristiken der systemischen Entzündung von denen der lokalen Fettgewebsentzündung unterscheiden. Die systemische Entzündung war gekennzeichnet durch höhere Spiegel gesättigter Fettsäuren (SFA), Tumor-necrosis-factor alpha (TNF-α), Interleukin IL-6, IL-8 und C-reactive protein (CRP) während die Konzentrationen von mehrfachungesättigten Fettsäuren (PUFA) –besonders n3-Fettsäuren- geringer in CC waren als in den anderen Gruppen. In vitro und in ex vivo kultivierten Fettgewebssegmenten konnte gezeigt werden, dass die Inkubation mit pro-inflammatorischen Cytokinen und gesättigten Fettsäuren zu einem Anstieg der Chemokine IL-8 sowie CXCL10 führte. Erhöhte Spiegel dieser Moleküle wurden auch in der Fettgewebsentzündung bei kachektischen Patienten beobachtet, welche im viszeralen Fettgewebe ausgeprägter war als im subkutanen. Systemische Entzündungsmarker waren negativ mit der Expression PUFA-synthetisierender Enzyme assoziiert, obwohl sich Gesamt-mRNA-sowie Proteingehalt kaum zwischen den Studiengruppen unterschieden. Die Effekte von Entzündungsfaktoren auf diese Enzyme im Gesamtgewebe könnten durch eine differenzielle Modulierung in diversen Zelltypen des Gewebes maskiert sein. Denn in in vitro-Experimenten zeigte die Inkubation mit TNF-α, IL-6, LPS oder Palmitat, dass die GeneExpression von Fettsäure-modifizierenden Enzymen wie Desaturasen oder Elongasen in Adipozyten und Makrophagen in entgegengesetzte Richtungen reguliert wird. Die höhere Plasmakonzentration des entzündungslösenden LM Resolvin D1 in CC konnte dem inflammatorischen Zustand nicht entgegenwirken und die Ergebnisse deuten darauf hin, dass inflammatorische Cytokine in die Synthesewege von entzündungslösenden LM eingreifen. Zusammenfassend demonstrieren die Daten das komplexe Zusammenspiel zwischen verschiedenen Geweben und Zelltypen, in dem Cytokine und Lipidverbindungen aus dem Blutkreislauf die Entzündung der Tumorkachexie durch selbst-verstärkende Mechanismen vorantreiben. N2 - A inflamação sistêmica é uma das características que marcam o diagnóstico da caquexia associada ao câncer. Entre as interações tumor-hospedeiro, o tecido adiposo branco contribui à inflamação, uma vez que ele sofre uma reorganização morfológica e lipólise, liberando ácidos graxos livres (AGLs), mediadores lipídicos (LMs) e citocinas pró-inflamatórias, que acentuam a ativação de vias de sinalização pró-inflamatória e o recrutamento de células do sistema imunológico para o tecido. O objetivo deste projeto foi investigar quais fatores inflamatórios sistêmicos estão envolvidos na inflamação do tecido adiposo e qual é a influência desses fatores sobre as enzimas envolvidas no metabolismo dos AGs ou LMs em indivíduos saudáveis (Controle), pacientes com câncer gastrointestinal com peso estável (WSC) e pacientes com câncer e caquexia (CC). Os resultados demonstraram que a resposta inflamatória sistêmica é diferente da resposta encontrada no tecido adiposo. A inflamação sistêmica dos pacientes com câncer e caquexia (CC) foi caracterizada por níveis circulantes mais elevados de ácidos graxos saturados (SFAs), tumor-necrosis-factor-α (TNF-α), Interleukin IL-6, IL-8 e proteina C-reativa (PCR), enquanto os níveis de ácidos graxos poliinsaturados (PUFAs), especialmente n3-PUFAs, foram menores em CC que nos demais grupos. In vitro e em explantes de tecido adiposo, citocinas pró-inflamatórias e SFAs aumentaram a expressão das quimiocinas IL-8 e CXCL10. E tambêm observamos um aumento na expressão destas quimiocinas na inflamação do tecido adiposo no CC, que era mais profundo no tecido adiposo visceral (VAT) quando comparado ao tecido adiposo subcutâneo (SAT). A inflamação sistêmica foi negativamente associada com a expressão de enzimas sintetizadoras dos PUFAs, embora a expressão gênica e protéica mostraram somente pequenas diferencias entre os grupos. Os efeitos dos fatores inflamatórios sobre as enzimas no tecido adiposo podem ter sido mascarados pela modulação diferenciada dos diversos tipos celulares constituintes desse tecido. Experimentos in vitro mostraram que a expressão de enzimas que modificam os AGs, tais como as dessaturases e elongases em adipócitos e macrófagos, foram reguladas em direções opostas por TNF-α, IL-6, LPS e palmitato. Mesmo os pacientes CC demonstrando uma maior concentração plasmática da Resolvina D1, que é um mediador lipídico de resolução da inflamação, ainda assim, a inflamação sistêmica é maior nesses pacientes, e os resultados indicam que as citoquinas inflamatórias interferem com as vias de síntese das LMs da resolução. Concluímos que, os dados revelaram um crosstalk inter-tecidual e intercelular complexo mediado por citocinas pró-inflamatórias e compostos lipídicos que aumentam a inflamação na caquexia associada ao câncer por mecanismos autoregulação. KW - cancer cachexia KW - inflammation KW - adipose tissue KW - cytokines KW - chemokines KW - SFA KW - PUFA Y1 - 2018 ER - TY - RPRT A1 - Amoroso, Sara A1 - Herrmann, Benedikt A1 - Kritikos, Alexander T1 - The Role of Regulation and Regional Government Quality for High Growth Firms BT - The Good, the Bad, and the Ugly T2 - CEPA Discussion Papers N2 - High growth firms (HGFs) are important for job creation and considered to be precursors of economic growth. We investigate how formal institutions, like product- and labor-market regulations, as well as the quality of regional governments that implement these regulations, affect HGF development across European regions. Using data from Eurostat, OECD, WEF, and Gothenburg University, we show that both regulatory stringency and the quality of the regional government influence the regional shares of HGFs. More importantly, we find that the effect of labor- and product-market regulations ultimately depends on the quality of regional governments: in regions with high quality of government, the share of HGFs is neither affected by the level of product market regulation, nor by more or less flexibility in hiring and firing practices. Our findings contribute to the debate on the effects of regulations by showing that regulations are not, per se, “good, bad, and ugly”, rather their impact depends on the efficiency of regional governments. Our paper offers important building blocks to develop tailored policy measures that may influence the development of HGFs in a region. T3 - CEPA Discussion Papers - 71 KW - High growth firms KW - Regulation KW - Quality of regional governments KW - Regions Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-612771 SN - 2628-653X IS - 71 ER - TY - JOUR A1 - Lessner, Daniel T1 - The role of algorithm in general secondary education revisited JF - Commentarii informaticae didacticae : (CID) N2 - The traditional purpose of algorithm in education is to prepare students for programming. In our effort to introduce the practically missing computing science into Czech general secondary education, we have revisited this purpose.We propose an approach, which is in better accordance with the goals of general secondary education in Czechia. The importance of programming is diminishing, while recognition of algorithmic procedures and precise (yet concise) communication of algorithms is gaining importance. This includes expressing algorithms in natural language, which is more useful for most of the students than programming. We propose criteria to evaluate such descriptions. Finally, an idea about the limitations is required (inefficient algorithms, unsolvable problems, Turing’s test). We describe these adjusted educational goals and an outline of the resulting course. Our experience with carrying out the proposed intentions is satisfactory, although we did not accomplish all the defined goals. KW - computing science education KW - general secondary education KW - mandatory computer science foundations KW - concept of algorithm Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-64534 SN - 1868-0844 SN - 2191-1940 IS - 6 SP - 99 EP - 110 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - THES A1 - Münch, Steffen T1 - The relevance of the aeolian transport path for the spread of antibiotic-resistant bacteria on arable fields T1 - Die Bedeutung des äolischen Transportpfads für die Ausbreitung antibiotikaresistenter Bakterien von Ackerböden N2 - The spread of antibiotic-resistant bacteria poses a globally increasing threat to public health care. The excessive use of antibiotics in animal husbandry can develop resistances in the stables. Transmission through direct contact with animals and contamination of food has already been proven. The excrements of the animals combined with a binding material enable a further potential path of spread into the environment, if they are used as organic manure in agricultural landscapes. As most of the airborne bacteria are attached to particulate matter, the focus of the work will be the atmospheric dispersal via the dust fraction. Field measurements on arable lands in Brandenburg, Germany and wind erosion studies in a wind tunnel were conducted to investigate the risk of a potential atmospheric dust-associated spread of antibiotic-resistant bacteria from poultry manure fertilized agricultural soils. The focus was to (i) characterize the conditions for aerosolization and (ii) qualify and quantify dust emissions during agricultural operations and wind erosion. PM10 (PM, particulate matter with an aerodynamic diameter smaller than 10 µm) emission factors and bacterial fluxes for poultry manure application and incorporation have not been previously reported before. The contribution to dust emissions depends on the water content of the manure, which is affected by the manure pretreatment (fresh, composted, stored, dried), as well as by the intensity of manure spreading from the manure spreader. During poultry manure application, PM10 emission ranged between 0.05 kg ha-1 and 8.37 kg ha-1. For comparison, the subsequent land preparation contributes to 0.35 – 1.15 kg ha-1 of PM10 emissions. Manure particles were still part of dust emissions but they were accounted to be less than 1% of total PM10 emissions due to the dilution of poultry manure in the soil after manure incorporation. Bacterial emissions of fecal origin were more relevant during manure application than during the subsequent manure incorporation, although PM10 emissions of manure incorporation were larger than PM10 emissions of manure application for the non-dried manure variants. Wind erosion leads to preferred detachment of manure particles from sandy soils, when poultry manure has been recently incorporated. Sorting effects were determined between the low-density organic particles of manure origin and the soil particles of mineral origin close above the threshold of 7 m s-1. In dependence to the wind speed, potential erosion rates between 101 and 854 kg ha-1 were identified, if 6 t ha-1 of poultry manure were applied. Microbial investigation showed that manure bacteria got detached more easily from the soil surface during wind erosion, due to their attachment on manure particles. Although antibiotic-resistant bacteria (ESBL-producing E. coli) were still found in the poultry barns, no further contamination could be detected with them in the manure, fertilized soils or in the dust generated by manure application, land preparation or wind erosion. Parallel studies of this project showed that storage of poultry manure for a few days (36 – 72 h) is sufficient to inactivate ESBL-producing E. coli. Further antibiotic-resistant bacteria, i.e. MRSA and VRE, were only found sporadically in the stables and not at all in the dust. Therefore, based on the results of this work, the risk of a potential infection by dust-associated antibiotic-resistant bacteria can be considered as low. N2 - Die Ausbreitung antibiotikaresistenter Bakterien stellt eine global zunehmende Gefahr für die öffentliche Gesundheitsfürsorge dar. Über den unsachgemäßen Einsatz von Antibiotika in der Tierhaltung können sich in den Ställen Resistenzen entwickeln. Übertragungen über den direkten Kontakt mit Tieren und der Kontaminierung von Lebensmitteln wurden bisher schon nachgewiesen. Die Exkremente der Tiere in Verbindung mit einem Bindemedium ermöglichen einen weiteren potentiellen Ausbreitungspfad in die Umwelt, wenn sie als organische Wirtschaftsdünger in Agrarlandschaften verwendet werden. Im Rahmen dieser Arbeit wurden Feld- und Windkanalmessungen durchgeführt, um dem von den Ackerflächen ausgehenden potentiellen Risiko einer partikulären Ausbreitung antibiotikaresistenter Bakterien nachzugehen. Kern der Arbeit ist zum einen die Bedingungen zu charakterisieren, die zu Staubemissionen während der Prozesskette (Düngerausbringung mit Geflügelmist, nachfolgende Feldbearbeitungen, Winderosion) führen, zum anderen Staubemissionen dieser Prozesskette zu klassifizieren und quantifizieren. Flächenbezogene Emissionen für PM10 als ein Teil des Schwebstaubs (sogenannte PM10 Emissionsfaktoren) wurden zum ersten Mal für die Düngerausbringung mit Geflügelmist bestimmt. Sie lagen zwischen 0,05 und 8,37 kg ha-1 PM10 und waren abhängig vom Wassergehalt des Materials, der durch die Vorbehandlungen (frisch, kompostiert, gelagert, getrocknet) der Düngervarianten bestimmt war. Im Vergleich dazu wurden für die nachfolgenden Bodenbearbeitungen zwischen 0,35 kg ha-1 und 1,15 kg ha-1 PM10 freigesetzt. Zwar waren Mistpartikel weiterhin Bestanteil der Staubemissionen während der Bodenbearbeitung, jedoch sank ihr Anteil durch die Verdünnung des Düngers im Boden nach der Düngereinarbeitung auf unter 1 % ab. Ähnliche Tendenzen ergaben sich bei der mikrobiellen Betrachtung der freigesetzten Bakterien während der Ausbringung und Einarbeitung des Geflügelmists. Trotz eines höheren PM10 Austrags während der Düngereinarbeitung, verglichen mit der Ausbringung des Düngers, waren die Bakterienemissionen während der Düngerausbringung relevanter als bei der Düngereinarbeitung. Winderosion sorgt für eine bevorzugte Verfrachtung des Geflügelmists auf sandigen Böden, nachdem der Dünger frisch eingearbeitet wurde. Da vor allem organische Bestandteile im Boden durch ihre geringe Dichte von der Auswehung betroffen sind, führt Winderosion auch bei mit Geflügelmist gedüngten Böden bereits kurz nach Erreichen der Schwellenwindgeschwindigkeit von 7 m s-1 zu einer Entmischung der eingebrachten organischen Mistpartikel und der mineralischen Bestandteile des Bodens. Diese Effekte treten vor allem dann auf, wenn in trockenen Böden der Gefügezustand zwischen mineralischen und organischen Partikeln kaum oder nicht vorhanden ist. In Abhängigkeit der Windgeschwindigkeit konnten potentielle Austräge zwischen 101 und 854 kg ha-1 bei einer eingebrachten Düngermenge von 6 t ha-1 bestimmt werden. Der bevorzugte Austrag von Mistpartikeln bedingt auch einen bevorzugten Austrag von Bakterien fäkalen Ursprungs, da diese nach der Einarbeitung an den Mistpartikeln mit geringerer Dichte anhaften. Obwohl in den Geflügelställen antibiotikaresistente Bakterien in Form von ESBL bildenden Escherichia Coli (E. coli) in hohen Keimzahlen gefunden wurden, konnten keine weiteren Kontaminationen mit resistenten E.coli im Mist, in gedüngten Böden oder im Staub nachgewiesen werden. Parallelstudien aus dem Projekt zeigten, dass eine mehrtägige Lagerung von Hühnerstreu ausreichend ist (36 – 72 h), die Mehrzahl resistenter E.coli zu reduzieren, sodass sie sich nach der Düngerausbringung nicht mehr über Agrarflächen ausbreiten konnten. Weitere antibiotikaresistente Bakterien (MRSA, VRE) wurden nur vereinzelt in den Ställen und überhaupt nicht im Staub nachgewiesen. Aus unseren Versuchen kann daher das Risiko einer möglichen Infektion durch staubassoziierte antibiotikaresistente Bakterien als gering eingeschätzt werden. KW - wind erosion KW - dust emission KW - PM10 KW - manure application KW - tillage KW - sandy soils KW - poultry manure KW - antibiotic resistance KW - airborne bacteria KW - agricultural KW - fecal contamination KW - fertilization KW - PM10 KW - landwirtschaftlich KW - luftgetragene Bakterien KW - Antibiotikaresistenz KW - Staubemission KW - fäkale Kontamination KW - Düngung KW - Mistausbringung KW - Geflügelmist KW - sandige Böden KW - Bodenbearbeitung KW - Winderosion Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-536089 ER - TY - GEN A1 - Höhle, Barbara A1 - Schmitz, Michaela A1 - Müller, Anja A1 - Weissenborn, Jürgen T1 - The recognition of discontinuous verbal dependencies by German 19-month-olds : evidence for lexical and structural influences on children’s early processing capacities N2 - Recent work has shown that English-learning 18-month-olds can detect the relationship between discontinuous morphemes such as is and -ing in Grandma is always running (Gomez, 2002; Santelmann & Jusczyk, 1998) but only at a maximum of 3 intervening syllables. In this article we examine the tracking of discontinuous dependencies in children acquiring German. Due to freer word order, German allows for greater distances between dependent elements and a greater syntactic variety of the intervening elements than English does. The aim of this study was to investigate whether factors other than distance may influence the child’s capacity to recognize discontinuous elements. Our findings provide evidence that children’s recognition capacities are affected not only by distance but also by their ability to linguistically analyze the material intervening between the dependent elements. We speculate that this result supports the existence of processing mechanisms that reduce a discontinuous relation to a local one based on subcategorization relations. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - paper 024 Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-16297 ER - TY - RPRT A1 - Kritikos, Alexander A1 - Schiersch, Alexander A1 - Stiel, Caroline T1 - The productivity puzzle in business services T2 - CEPA Discussion Papers N2 - In Germany, the productivity of professional services, a sector dominated by micro and small firms, declined by 40 percent between 1995 and 2014. This productivity decline also holds true for professional services in other European countries. Using a German firm-level dataset of 700,000 observations between 2003 and 2017, we analyze this largely uncovered phenomenon among professional services, the 4th largest sector in the EU15 business economy, which provide important intermediate services for the rest of the economy. We show that changes in the value chain explain about half of the decline and the increase in part-time employment is a further minor part of the decline. In contrast to expectations, the entry of micro and small firms, despite their lower productivity levels, is not responsible for the decline. We also cannot confirm the conjecture that weakening competition allows unproductive firms to remain in the market. T3 - CEPA Discussion Papers - 37 KW - business services KW - labor productivity KW - productivity slowdown Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-514536 SN - 2628-653X IS - 37 ER - TY - JOUR A1 - Wassner, Dalia T1 - The Port Jew and Nuestra América BT - Narratives of Collective Responsibility and Belonging JF - PaRDeS : Journal of the Association for Jewish Studies in Germany JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien e.V. N2 - Jacob Brandon Maduro’s Memoirs and Related Observations (Havana, 1953) speak to the lasting yet malleable legacy of Jewish Caribbean/Atlantic mercantile communities that defined early modern settlement in the Americas. A close reading of the Memoirs, alongside relevant archival records and community narratives, lends new perspectives to scholarship on Port Jewries and the Atlantic Diaspora. Specifically concerned with Jacob’s adoption of such leading intellectual and political tropes as the Monroe doctrine, José Martí’s Nuestra America, and a Zionism that evolved from an ideology to a reality, the Memoirs reveal a narrative at once defined by the tremendous upheavals of the first half of the 20th century, and an enduring sense of Jewish diasporic peoplehood defined through a Port Jew paradigm whereby the preservation of Jewish ethnicity is understood as synonymous with the championing of modernity. Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-585580 SN - 978-3-86956-552-1 SN - 1614-6492 SN - 1862-7684 IS - 28 SP - 84 EP - 99 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Große-Bölting, Gregor A1 - Scheppach, Lukas A1 - Mühling, Andreas T1 - The Place of Ethics in Computer Science Education JF - Hochschuldidaktik Informatik HDI 2021 (Commentarii informaticae didacticae) N2 - Ethical issues surrounding modern computing technologies play an increasingly important role in the public debate. Yet, ethics still either doesn’t appear at all or only to a very small extent in computer science degree programs. This paper provides an argument for the value of ethics beyond a pure responsibility perspective and describes the positive value of ethical debate for future computer scientists. It also provides a systematic analysis of the module handbooks of 67 German universities and shows that there is indeed a lack of ethics in computer science education. Finally, we present a principled design of a compulsory course for undergraduate students. KW - Ethics KW - Diversity KW - Social impact KW - Bachelor KW - Curriculum analysis KW - Course development Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-615982 SN - 978-3-86956-548-4 SN - 1868-0844 SN - 2191-1940 IS - 13 SP - 173 EP - 187 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Baritello, Omar A1 - Salzwedel, Annett A1 - Sündermann, Simon A1 - Niebauer, Josef A1 - Völler, Heinz T1 - The Pandora's Box of frailty assessments: Which is the best for clinical purposes in TAVI patients? A critical review JF - Journal of Clinical Medicine N2 - Frailty assessment is recommended before elective transcatheter aortic valve implantation (TAVI) to determine post-interventional prognosis. Several studies have investigated frailty in TAVI-patients using numerous assessments; however, it remains unclear which is the most appropriate tool for clinical practice. Therefore, we evaluate which frailty assessment is mainly used and meaningful for ≤30-day and ≥1-year prognosis in TAVI patients. Randomized controlled or observational studies (prospective/retrospective) investigating all-cause mortality in older (≥70 years) TAVI patients were identified (PubMed; May 2020). In total, 79 studies investigating frailty with 49 different assessments were included. As single markers of frailty, mostly gait speed (23 studies) and serum albumin (16 studies) were used. Higher risk of 1-year mortality was predicted by slower gait speed (highest Hazard Ratios (HR): 14.71; 95% confidence interval (CI) 6.50–33.30) and lower serum albumin level (highest HR: 3.12; 95% CI 1.80–5.42). Composite indices (five items; seven studies) were associated with 30-day (highest Odds Ratio (OR): 15.30; 95% CI 2.71–86.10) and 1-year mortality (highest OR: 2.75; 95% CI 1.55–4.87). In conclusion, single markers of frailty, in particular gait speed, were widely used to predict 1-year mortality. Composite indices were appropriate, as well as a comprehensive assessment of frailty. View Full-Text KW - frailty tool KW - TAVI KW - older patients KW - elderly KW - cardiology KW - mortality Y1 - 2021 U6 - https://doi.org/10.3390/jcm10194506 SN - 2077-0383 VL - 10 SP - 1 EP - 17 PB - MDPI CY - Basel, Schweiz ET - 19 ER - TY - JOUR A1 - Nakano, Yoshiaki A1 - Izutsu, Katsunobu T1 - The new course of study and a prospect of information studies education in Japan JF - Commentarii informaticae didacticae : (CID) N2 - Japan launched the new Course of Study in April 2012, which has been carried out in elementary schools and junior high schools. It will also be implemented in senior high schools from April 2013. This article presents an overview of the information studies education in the new Course of Study for K-12. Besides, the authors point out what role experts of informatics and information studies education should play in the general education centered around information studies that is meant to help people of the nation to lead an active, powerful, and flexible life until the satisfying end. KW - General subject “Information” KW - Course of Study KW - Scientific understanding of Information KW - Information Ethics Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-64522 SN - 1868-0844 SN - 2191-1940 IS - 6 SP - 89 EP - 96 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - THES A1 - Pons, Michaël T1 - The Nature of the tectonic shortening in Central Andes T1 - Die Beschaffenheit der tektonischen Verkürzung in den Zentralanden N2 - The Andean Cordillera is a mountain range located at the western South American margin and is part of the Eastern- Circum-Pacific orogenic Belt. The ~7000 km long mountain range is one of the longest on Earth and hosts the second largest orogenic plateau in the world, the Altiplano-Puna plateau. The Andes are known as a non-collisional subduction-type orogen which developed as a result of the interaction between the subducted oceanic Nazca plate and the South American continental plate. The different Andean segments exhibit along-strike variations of morphotectonic provinces characterized by different elevations, volcanic activity, deformation styles, crustal thickness, shortening magnitude and oceanic plate geometry. Most of the present-day elevation can be explained by crustal shortening in the last ~50 Ma, with the shortening magnitude decreasing from ~300 km in the central (15°S-30°S) segment to less than half that in the southern part (30°S-40°S). Several factors were proposed that might control the magnitude and acceleration of shortening of the Central Andes in the last 15 Ma. One important factor is likely the slab geometry. At 27-33°S, the slab dips horizontally at ~100 km depth due to the subduction of the buoyant Juan Fernandez Ridge, forming the Pampean flat-slab. This horizontal subduction is thought to influence the thermo-mechanical state of the Sierras Pampeanas foreland, for instance, by strengthening the lithosphere and promoting the thick-skinned propagation of deformation to the east, resulting in the uplift of the Sierras Pampeanas basement blocks. The flat-slab has migrated southwards from the Altiplano latitude at ~30 Ma to its present-day position and the processes and consequences associated to its passage on the contemporaneous acceleration of the shortening rate in Central Andes remain unclear. Although the passage of the flat-slab could offer an explanation to the acceleration of the shortening, the timing does not explain the two pulses of shortening at about 15 Ma and 4 Ma that are suggested from geological observations. I hypothesize that deformation in the Central Andes is controlled by a complex interaction between the subduction dynamics of the Nazca plate and the dynamic strengthening and weakening of the South American plate due to several upper plate processes. To test this hypothesis, a detailed investigation into the role of the flat-slab, the structural inheritance of the continental plate, and the subduction dynamics in the Andes is needed. Therefore, I have built two classes of numerical thermo-mechanical models: (i) The first class of models are a series of generic E-W-oriented high-resolution 2D subduction models thatinclude flat subduction in order to investigate the role of the subduction dynamics on the temporal variability of the shortening rate in the Central Andes at Altiplano latitudes (~21°S). The shortening rate from the models was then validated with the observed tectonic shortening rate in the Central Andes. (ii) The second class of models are a series of 3D data-driven models of the present-day Pampean flat-slab configuration and the Sierras Pampeanas (26-42°S). The models aim to investigate the relative contribution of the present-day flat subduction and inherited structures in the continental lithosphere on the strain localization. Both model classes were built using the advanced finite element geodynamic code ASPECT. The first main finding of this work is to suggest that the temporal variability of shortening in the Central Andes is primarily controlled by the subduction dynamics of the Nazca plate while it penetrates into the mantle transition zone. These dynamics depends on the westward velocity of the South American plate that provides the main crustal shortening force to the Andes and forces the trench to retreat. When the subducting plate reaches the lower mantle, it buckles on it-self until the forced trench retreat causes the slab to steepen in the upper mantle in contrast with the classical slab-anchoring model. The steepening of the slab hinders the trench causing it to resist the advancing South American plate, resulting in the pulsatile shortening. This buckling and steepening subduction regime could have been initiated because of the overall decrease in the westwards velocity of the South American plate. In addition, the passage of the flat-slab is required to promote the shortening of the continental plate because flat subduction scrapes the mantle lithosphere, thus weakening the continental plate. This process contributes to the efficient shortening when the trench is hindered, followed by mantle lithosphere delamination at ~20 Ma. Finally, the underthrusting of the Brazilian cratonic shield beneath the orogen occurs at ~11 Ma due to the mechanical weakening of the thick sediments covered the shield margin, and due to the decreasing resistance of the weakened lithosphere of the orogen. The second main finding of this work is to suggest that the cold flat-slab strengthens the overriding continental lithosphere and prevents strain localization. Therefore, the deformation is transmitted to the eastern front of the flat-slab segment by the shear stress operating at the subduction interface, thus the flat-slab acts like an indenter that “bulldozes” the mantle-keel of the continental lithosphere. The offset in the propagation of deformation to the east between the flat and steeper slab segments in the south causes the formation of a transpressive dextral shear zone. Here, inherited faults of past tectonic events are reactivated and further localize the deformation in an en-echelon strike-slip shear zone, through a mechanism that I refer to as “flat-slab conveyor”. Specifically, the shallowing of the flat-slab causes the lateral deformation, which explains the timing of multiple geological events preceding the arrival of the flat-slab at 33°S. These include the onset of the compression and of the transition between thin to thick-skinned deformation styles resulting from the crustal contraction of the crust in the Sierras Pampeanas some 10 and 6 Myr before the Juan Fernandez Ridge collision at that latitude, respectively. N2 - Die Andenkordillere ist ein Gebirgszug am westlichen Rand Südamerikas und Teil des östlichen zirkumpazifischen Gebirgsgürtels. Der ~7000 km lange Gebirgszug ist einer der längsten der Erde und beherbergt mit dem Altiplano-Puna-Plateau das zweitgrößte orogenetische Plateau der Welt. Die Anden sind als nicht-kollisionsbedingtes Subduktionsgebirge bekannt, das durch die Wechselwirkung zwischen der subduzierten ozeanischen Nazca-Platte und der südamerikanischen Kontinentalplatte entstanden ist. Entlang des Höhenzugs der Anden lassen sich Segmente unterschiedlicher morphotektonischer Provinzen ausmachen, die durch Variationen in topographischer Höhe, vulkanischer Aktivität, Deformationsform, Krustendicke, Krustenverkürzung und ozeanischer Plattengeometrie gekennzeichnet sind. Der größte Teil der heutigen Hebung lässt sich durch die Krustenverkürzung der letzten 50 Mio. Jahre erklären, wobei das Ausmaß der Verkürzung von ca. 300 km im zentralen Segment (15°S-30°S) auf weniger als die Hälfte im südlichen Teil (30°S-40°S) abnimmt. Es wurden mehrere Faktoren vorgeschlagen, die das Ausmaß und die Beschleunigung der Verkürzung der zentralen Anden in den letzten 15 Mio. Jahren beeinflusst haben könnten. Ein wichtiger Faktor ist wahrscheinlich die Plattengeometrie. Durch die Subduktion des Juan-Fernandez-Rückens und dessen hohe Auftriebskraft fällt die Platte bei 27-33°S in ~100 km Tiefe horizontal ein und bildet den pampeanischen flat-slab. Es wird angenommen, dass die horizontale Subduktion den thermomechanischen Zustand des Sierras-Pampeanas-Vorlandes beeinflusst, indem sie beispielsweise die Lithosphäre stärkt und die dickschalige Verlagerung der Deformation nach Osten sowie die Hebung der kristallinen Basis der Sierras-Pampeanas fördert. Vor etwa 30 Mio. Jahren verschob sich der flat-slab von der geographischen Breite des Altiplano zu seiner heutigen Position nach Süden. Die mit der Positionsverlagerung verbundenen Prozesse und Folgen für die gleichzeitige Beschleunigung der Verkürzungsraten in den zentralen Anden sind noch immer unklar. Obwohl die Passage des flat-slab eine Erklärung für dafür sein könnte, erklärt ihr Zeitpunkt nicht die beiden aus der Geologie abgeleiteten Verkürzungsimpulse vor etwa 15 und 4 Mio. Jahren. Ich stelle die Hypothese auf, dass die Deformation in den zentralen Anden durch eine komplexe Wechselwirkung zwischen der Subduktionsdynamik der Nazca-Platte und der dynamischen Materialschwächung der südamerikanischen Platte aufgrund einer Reihe von Prozessen in der oberen Platte gesteuert wird. Um diese Hypothese zu prüfen, ist eine detaillierte Untersuchung der Rolle des flat-slab, sowie der strukturellen Vererbung der Kontinentalplatte und der Subduktionsdynamik in den Anden erforderlich. Daher habe ich zwei Klassen von numerischen thermomechanischen Modellen erstellt: (i) Die erste Klasse von Modellen umfasst eine Reihe von generischen E-W-orientierten 2D-Subduktionsmodellen mit hoher Auflösung. Diese beinhalten subhorizontalen Subduktion um die Rolle der Subduktionsdynamik auf die zeitliche Variabilität der Verkürzungsrate in den zentralen Anden auf dem Altiplano (~21°S) zu untersuchen. Die modellierte Verkürzungsrate wurde mit der beobachteten tektonischen Verkürzungsrate in den zentralen Anden validiert. (ii) Die zweite Klasse von Modellen besteht aus einer Reihe von datengesteuerten 3D-Modellen der heutigen pampeanischen flat-slab-Konfiguration und der Sierras Pampeanas (26-42°S). Diese Modelle zielen darauf ab, den relativen Beitrag der heutigen subhorizontalen Subduktion und der ererbten Strukturen in der kontinentalen Lithosphäre zur Dehnungslokalisierung zu untersuchen. Beide Modellklassen wurden mit Hilfe des fortschrittlichen geodynamischen Finite-Elemente-Codes ASPECT erstellt. Das erste Hauptergebnis dieser Arbeit ist die Vermutung, dass zeitliche Änderungen der Verkürzung in den Zentralanden in erster Linie durch die Subduktionsdynamik der Nazca-Platte gesteuert werden, während diese in die Mantelübergangszone eindringt. Die Dynamik hängt von der westwärts gerichteten Geschwindigkeit der südamerikanischen Platte ab, die die Hauptantriebskraft für die Krustenverkürzung in den Anden darstellt und den Subduktionsgraben zum Zurückziehen zwingt. Wenn die subduzierende Platte den unteren Erdmantel erreicht, wölbt sie sich auf, bis der erzwungene Rückzug des Grabens dazu führt, dass auch die Platte im oberen Erdmantel steiler wird. Die aufgesteilte Platte behindert wiederum den Graben, der sich der vorrückenden südamerikanischen Platte widersetzt, was eine pulsierende Verkürzung zur Folge hat. Dieses Subduktionsregime, bestehend aus Aufwölbung und Aufsteilung, könnte durch die allgemeine westwärts gerichtete Geschwindigkeitsabnahme der südamerikanischen Platte ausgelöst worden sein. Der Durchgang des flat-slab ist zudem eine notwendige Bedingung, um die Verkürzung der Kontinentalplatte voran zu treiben, da subhorizontale Subduktion Teile der Mantellithosphäre abträgt und so die Kontinentalplatte schwächt. Dieser Prozess trägt somit zur effizienten Verkürzung bei während der Graben behindert wird und ist gefolgt von der Ablösung der Mantellithosphäre vor etwa 20 Mio. Jahren. Das Subduzieren des brasilianischen kratonischen Schildes unter das Orogen erfolgte schließlich vor etwa 11 Mio. Jahren aufgrund der mechanischen Schwächung der dicken Sedimentschicht, die den Schildrand bedeckte, sowie wegen des abnehmenden Widerstands der geschwächten Gebirgslithosphäre. Das zweite Hauptergebnis dieser Arbeit ist die Vermutung, dass der kalte flat-slab die darüber liegende kontinentale Lithosphäre stärkt und damit verhindert, dass sich Verformungen lokalisieren können. Daher wird die Deformation durch die an der Subduktionsfläche wirkende Scherspannung auf die östliche Front des flat-slab-Segments übertragen. Der flat-slab wirkt wie ein Eindringling, der die unter mantle-keel bekannte Anhäufung von abgelöstem Mantelmaterial beiseite schiebt. Der Versatz in der ostwärts gerichteten Deformationsausbreitung der flachen und der steileren Plattensegmenten im Süden führt zur Bildung einer transpressiven dextralen Scherungszone. Hier werden ererbte Verwerfungen vergangener tektonischer Ereignisse reaktiviert und helfen bei der Lokalisierung neuer Deformation in einer en-echelon-artigen Scherungszone. Dies geschieht durch einen Mechanismus, den ich als "flat-slab-Conveyor" bezeichne. Das laterale Zusammenschieben wird besonders durch das Flacherwerden des flat-slab beeinflusst, welches den Zeitpunkt mehrerer geologischer Ereignisse erklärt, die der Ankunft des flat-slab bei 33°S vorangehen. Dazu gehören der Beginn der Kompression und der Übergang von dünn- zu dickschaliger Deformation, die sich aus der Krustenkontraktion in den Sierras Pampeanas etwa 10 bzw. 6 Mio. Jahre vor der Kollision mit dem Juan-Fernandez-Rücken auf diesem Breitengrad ergaben. KW - Andes KW - Orogen KW - tectonics KW - Subduction KW - Deformation KW - Shortening KW - Flat subduction KW - Geodynamics KW - Altiplano KW - Puna KW - Sierras Pampeanas KW - Foreland KW - Altiplano KW - Anden KW - Deformation KW - Flache Subduktion KW - Vorland KW - Geodynamik KW - Orogen KW - Puna KW - Verkürzung KW - Sierras Pampeanas KW - Subduktion KW - Tektonik Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-600892 ER - TY - JOUR A1 - Verlaan, Stephanie T1 - The Misapplication of Western Conflict and Reconciliation Theories on New World Wars JF - Transitional Justice : Theoretical and Practical Approaches (Potsdamer Studien zu Staat, Recht und Politik ; 7) N2 - This chapter deals with the problem that theories of peace building, conflict resolution and reconciliation were predominately created in the West and, therefore, do not necessarily fit the understanding of peace, conflict, and resolution in non-Western societies and cultures. Within these societies, the acceptance of suffering may also be higher, which leads to different priorities of conflict resolution approaches. Furthermore, this chapter deals with the question of whether the current understanding of wars and the nature of conflict change the basis of established conflict theories. These theoretical approaches are then applied in Sierra Leone as a non-Western negotiation scenario. Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-570149 SN - 978-3-86956-473-9 SN - 1869-2443 SN - 1867-2663 IS - 7 SP - 11 EP - 38 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - THES A1 - De Andrade Queiroz, Anna Barbara T1 - The Milky Way disks, bulge, and bar sub-populations T1 - Die Scheiben, der Bulge und der Balken der Milchstraße Subpopulationen BT - a chemo-dynamical view of our Galaxy in the APOGEE + Gaia era BT - ein chemodynamischer Blick auf unsere Galaxie in der APOGEE + Gaia Ära N2 - In recent decades, astronomy has seen a boom in large-scale stellar surveys of the Galaxy. The detailed information obtained about millions of individual stars in the Milky Way is bringing us a step closer to answering one of the most outstanding questions in astrophysics: how do galaxies form and evolve? The Milky Way is the only galaxy where we can dissect many stars into their high-dimensional chemical composition and complete phase space, which analogously as fossil records can unveil the past history of the genesis of the Galaxy. The processes that lead to large structure formation, such as the Milky Way, are critical for constraining cosmological models; we call this line of study Galactic archaeology or near-field cosmology. At the core of this work, we present a collection of efforts to chemically and dynamically characterise the disks and bulge of our Galaxy. The results we present in this thesis have only been possible thanks to the advent of the Gaia astrometric satellite, which has revolutionised the field of Galactic archaeology by precisely measuring the positions, parallax distances and motions of more than a billion stars. Another, though not less important, breakthrough is the APOGEE survey, which has observed spectra in the near-infrared peering into the dusty regions of the Galaxy, allowing us to determine detailed chemical abundance patterns in hundreds of thousands of stars. To accurately depict the Milky Way structure, we use and develop the Bayesian isochrone fitting tool/code called StarHorse; this software can predict stellar distances, extinctions and ages by combining astrometry, photometry and spectroscopy based on stellar evolutionary models. The StarHorse code is pivotal to calculating distances where Gaia parallaxes alone cannot allow accurate estimates. We show that by combining Gaia, APOGEE, photometric surveys and using StarHorse, we can produce a chemical cartography of the Milky way disks from their outermost to innermost parts. Such a map is unprecedented in the inner Galaxy. It reveals a continuity of the bimodal chemical pattern previously detected in the solar neighbourhood, indicating two populations with distinct formation histories. Furthermore, the data reveals a chemical gradient within the thin disk where the content of 𝛼-process elements and metals is higher towards the centre. Focusing on a sample in the inner MW we confirm the extension of the chemical duality to the innermost regions of the Galaxy. We find stars with bar shape orbits to show both high- and low-𝛼 abundances, suggesting the bar formed by secular evolution trapping stars that already existed. By analysing the chemical orbital space of the inner Galactic regions, we disentangle the multiple populations that inhabit this complex region. We reveal the presence of the thin disk, thick disk, bar, and a counter-rotating population, which resembles the outcome of a perturbed proto-Galactic disk. Our study also finds that the inner Galaxy holds a high quantity of super metal-rich stars up to three times solar suggesting it is a possible repository of old super-metal-rich stars found in the solar neighbourhood. We also enter into the complicated task of deriving individual stellar ages. With StarHorse, we calculate the ages of main-sequence turn-off and sub-giant stars for several public spectroscopic surveys. We validate our results by investigating linear relations between chemical abundances and time since the 𝛼 and neutron capture elements are sensitive to age as a reflection of the different enrichment timescales of these elements. For further study of the disks in the solar neighbourhood, we use an unsupervised machine learning algorithm to delineate a multidimensional separation of chrono-chemical stellar groups revealing the chemical thick disk, the thin disk, and young 𝛼-rich stars. The thick disk is shown to have a small age dispersion indicating its fast formation contrary to the thin disk that spans a wide range of ages. With groundbreaking data, this thesis encloses a detailed chemo-dynamical view of the disk and bulge of our Galaxy. Our findings on the Milky Way can be linked to the evolution of high redshift disk galaxies, helping to solve the conundrum of galaxy formation. N2 - In den letzten Jahrzehnten hat die Astronomie mit großen galaktischen Durchmusterungen einen Boom erlebt. Die dadurch gewonnenen detaillierten Informationen über Millionen von Einzelsternen in der Milchstraße bringen uns der Beantwortung einer der wichtigsten Fragen der Astrophysik einen Schritt näher: Wie entstehen und entwickeln sich Galaxien? Die Milchstraße ist die einzige Galaxie, in der wir viele Sterne in ihre hochdimensionale chemische Zusammensetzung und ihren vollständigen Phasenraum zerlegen können, was analog zu fossilen Aufzeichnungen die Entstehungsgeschichte der Galaxie enthüllen kann. Für kosmologische Modelle ist es von entscheidender Bedeutung, die Prozesse zu verstehen, die zur Bildung großer Strukturen wie der Milchstraße führen; wir nennen diese Studienrichtung Galaktische Archäologie oder Nahfeldkosmologie. Im Mittelpunkt dieser Arbeit stehen die Bemühungen, die Scheiben und den Bulge unserer Galaxie chemisch und dynamisch zu charakterisieren. Die Ergebnisse, die wir in dieser Arbeit vorstellen, waren nur dank des starts des astrometrischen Satelliten Gaia möglich, der das Gebiet der galaktischen Archäologie durch die präzise Messung der Positionen, Parallaxenwinkel und Eigenbewegungen von mehr als einer Milliarde Sterne revolutioniert hat. Ein weiterer, aber nicht minder wichtiger Durchbruch ist die APOGEE-Durchmusterung, die Spektren im nahen Infrarot beobachtet hat, was es uns erlaubt, durch die staubigen Regionen der Milchstraße hindurchzublicken und die chemischen Fingerabdrücke von Hunderttausenden von Sternen zu bestimmen. Um die Struktur der Milchstraße genau darzustellen, verwenden und entwickeln wir das Isochrone-fitting-Tool StarHorse; diese Software kann Sternentfernungen, Aussterbezeiten und Alter vorhersagen, indem sie Astrometrie, Photometrie und Spektroskopie auf der Grundlage von Modellen der Sternentwicklung kombiniert. Der Code StarHorse ist von zentraler Bedeutung für die Berechnung von Entfernungen, bei denen Gaia -Parallaxen allein keine Bestimmung ermöglichen. Wir zeigen, dass wir durch die Kombination von Gaia, APOGEE und StarHorse eine chemische Kartographie der Milchstraßenscheiben von ihrem äußersten bis zum innersten Teil erstellen können. Eine solche Karte ist in der inneren Galaxis beispiellos und zeigt ein bimodales chemisches Muster, das auf zwei Populationen mit unterschiedlichen Entstehungsgeschichten hinweist. Darüber hinaus bestätigen die Daten einen chemischen Gradienten innerhalb der dünnen Scheibe, bei dem der Gehalt an Elementen und Metallen aus 𝛼-Prozessen zum Zentrum hin zunimmt ist. Eine Überdichte in der Anzahl der Sterne bestätigt zudem die Signatur eines Balkens in der inneren Galaxie. Modelle der Galaxienentstehung sagen gewöhnlich deren Beginn im galaktischen Zentrum voraus. Wir konzentrieren uns auf eine Stichprobe in der inneren Galaxie und erwarten, dass wir primordiale stellare Populationen finden. Wir bestätigen die chemische Bimodalität der inneren Galaxie und dass der galaktische Balken sowohl aus Sternen mit hohem als auch mit niedrigem 𝛼 besteht, was darauf hindeutet, dass sich der Balken durch säkulare Evolution gebildet hat, bei der bereits existierende Sterne eingefangen wurden. Durch die Analyse des chemischen Orbitalraums der inneren galaktischen Regionen können wir die verschiedenen Populationen, die diese komplexe Region bewohnen, unterscheiden. Wir zeigen das Vorhandensein einer dünnen Scheibe, einer dicken Scheibe, eines Balkens und einer gegenläufig rotierenden Population, die dem Ergebnis einer gestörten proto-galaktischen Scheibe ähnelt. Unsere Studie zeigt auch, dass die innere Galaxie eine große Menge an supermetallreichen Sternen enthält, die bis zum Dreifachen der solaren Metallizität reichen. Möglicherweise handelt es sich bei der Gruppe alter supermetallreicher Sterne, die in der Sonnenumgebung gefunden wurden um Kandidaten für Migranten aus den innersten Regionen. Wir befassen uns auch mit der komplizierten Aufgabe der Bestimmung individueller Sternalter. Mit StarHorse berechnen wir das Alter von Hauptreihenabzweig- und Unterriesensternen für mehrere öffentliche spektroskopische Durchmusterungen. Wir validieren unsere Ergebnisse, indem wir lineare Abhängigkeiten zwischen den chemischen Häufigkeiten und der Zeit untersuchen, da die 𝛼- und Neutroneneinfang-Elemente empfindlich auf das Alter reagieren, was auf die unterschiedlichen Zeitskalen der Anreicherung dieser Elemente zurückzuführen ist. Zur weiteren Untersuchung der Scheiben in der Sonnenumgebung verwenden wir einen nicht überwachten Algorithmus für maschinelles Lernen, um eine mehrdimensionale Trennung der chrono-chemischen Sterngruppen vorzunehmen. Dies macht die chemisch dicke Scheibe, die dünne Scheibe und junge 𝛼 Sterne erkennbar. Es zeigt sich, dass die dicke Scheibe eine geringe Altersstreuung aufweist, was auf ihre schnelle Entstehung hindeutet, während die dünne Scheibe eine große Altersspanne abdeckt. Mit bahnbrechenden Daten liefert diese Arbeit ein detailliertes chemodynamisches Bild der Scheibe und des Bulge der Galaxis. Unsere Erkenntnisse über die Milchstraße können mit der Entwicklung von Scheibengalaxien mit hoher Rotverschiebung in Verbindung gebracht werden und so zur Lösung des Rätsels der Galaxienbildung beitragen. KW - stars: distances KW - fundamental parameters KW - statistics KW - galaxy: general KW - disc KW - bulge KW - stellar content KW - Bulge KW - Scheibe KW - fundamentale Parameter KW - Galaxie: allgemein KW - Sterne: Entfernungen KW - Statistik KW - stellarer Inhalt Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-590615 ER - TY - JOUR A1 - Heissel, Andreas A1 - Pietrek, Anou F. A1 - Kangas, Maria A1 - Van der Kaap-Deeder, Jolene A1 - Rapp, Michael A. T1 - The Mediating Role of Rumination in the Relation between Basic Psychological Need Frustration and Depressive Symptoms JF - Journal of Clinical Medicine N2 - Research within the framework of Basic Psychological Need Theory (BPNT) finds strong associations between basic need frustration and depressive symptoms. This study examined the role of rumination as an underlying mechanism in the association between basic psychological need frustration and depressive symptoms. A cross-sectional sample of N = 221 adults (55.2% female, mean age = 27.95, range = 18–62, SD = 10.51) completed measures assessing their level of basic psychological need frustration, rumination, and depressive symptoms. Correlational analyses and multiple mediation models were conducted. Brooding partially mediated the relation between need frustration and depressive symptoms. BPNT and Response Styles Theory are compatible and can further advance knowledge about depression vulnerabilities. KW - psychopathology KW - elf-determination theory KW - response styles theory KW - frustration KW - depressive disorder KW - emotional regulation KW - rumination Y1 - 2023 U6 - https://doi.org/10.3390/jcm12020395 SN - 2077-0383 VL - 12 SP - 1 EP - 10 PB - MDPI CY - Basel, Schweiz ET - 2 ER - TY - THES A1 - Kolk, Jens T1 - The long-term legacy of historical land cover changes T1 - Die Langzeitfolgen historischer Landbedeckungsveränderungen BT - patterns and dynamics in herb-layer species richness in deciduous forests of the Prignitz region (NE Germany) BT - Muster und Dynamik der Artenvielfalt von Waldpflanzengemeinschaften in Laubwäldern der Prignitz (Nordostdeutschland) N2 - Over the last years there is an increasing awareness that historical land cover changes and associated land use legacies may be important drivers for present-day species richness and biodiversity due to time-delayed extinctions or colonizations in response to historical environmental changes. Historically altered habitat patches may therefore exhibit an extinction debt or colonization credit and can be expected to lose or gain species in the future. However, extinction debts and colonization credits are difficult to detect and their actual magnitudes or payments have rarely been quantified because species richness patterns and dynamics are also shaped by recent environmental conditions and recent environmental changes. In this thesis we aimed to determine patterns of herb-layer species richness and recent species richness dynamics of forest herb layer plants and link those patterns and dynamics to historical land cover changes and associated land use legacies. The study was conducted in the Prignitz, NE-Germany, where the forest distribution remained stable for the last ca. 100 years but where a) the deciduous forest area had declined by more than 90 per cent (leaving only remnants of "ancient forests"), b) small new forests had been established on former agricultural land ("post-agricultural forests"). Here, we analyzed the relative importance of land use history and associated historical land cover changes for herb layer species richness compared to recent environmental factors and determined magnitudes of extinction debt and colonization credit and their payment in ancient and post-agricultural forests, respectively. We showed that present-day species richness patterns were still shaped by historical land cover changes that ranged back to more than a century. Although recent environmental conditions were largely comparable we found significantly more forest specialists, species with short-distance dispersal capabilities and clonals in ancient forests than in post-agricultural forests. Those species richness differences were largely contingent to a colonization credit in post-agricultural forests that ranged up to 9 species (average 4.7), while the extinction debt in ancient forests had almost completely been paid. Environmental legacies from historical agricultural land use played a minor role for species richness differences. Instead, patch connectivity was most important. Species richness in ancient forests was still dependent on historical connectivity, indicating a last glimpse of an extinction debt, and the colonization credit was highest in isolated post-agricultural forests. In post-agricultural forests that were better connected or directly adjacent to ancient forest patches the colonization credit was way smaller and we were able to verify a gradual payment of the colonization credit from 2.7 species to 1.5 species over the last six decades. N2 - In den vergangenen Jahren reift immer mehr die Erkenntnis, dass historische Landnutzungsveränderungen und deren Folgewirkungen einen wichtigen Einfluss auf die heutige Artenvielfalt und Biodiversität haben können. In Habitaten, deren Landnutzung und Fläche sich in historischer Zeit verändert hat kann aufgrund von verzögerten Aussterbe- und Einwanderungsprozessen eine erhöhte oder verringerte Artenvielfalt vorliegen, die nicht den heutigen Umweltbedingungen entspricht. Es liegen Aussterbeschulden oder Einwanderungs- bzw. Kolonisierungskredite vor, welcher über die Zeit mit Artverlusten oder Zugewinnen von Arten bezahlt werden. Aussterbeschulden oder Einwanderungskredite und deren Bezahlung sind schwierig zu ermitteln, da einerseits Informationen zu historischen Landnutzungsveränderungen oft fehlen und andererseits auch heutige Umweltfaktoren einen wichtigen Einfluss auf die Artenvielfalt haben. Das Ziel dieser Arbeit war es die heutigen Muster der Artenvielfalt von Waldbodenpflanzen in Laub- und Mischwäldern und deren Veränderungen über die letzten 60 Jahre zu ermitteln und diese Muster im Hinblick auf historische Landnutzungsveränderungen zu untersuchen. Das Studiengebiet umfasst große Teile der Prignitz (Brandenburg und angrenzende Teile von Sachsen-Anhalt), ein Gebiet, dessen Waldanteil sich in den letzten 100 Jahren kaum verändert hat, in dem sich jedoch seit dem Ende des 19ten Jahrhunderts der Anteil historisch alter Wälder (ohne historische nachgewiesene agrarliche Nutzung) um mehr als 90% reduziert hat, während an anderer Stelle wenige neue Wälder auf vorigen Agrarflächen etabliert wurden. Im Rahmen dieser Studie wurde zunächst die Artenvielfalt und deren aktuelle Veränderung in historisch-alten Wäldern und neu etablierten Wäldern untersucht und verglichen. Um den Einfluss von historischen Landnutzungsveränderungen auf die Artenvielfalt zu ermittlen, wurde die historische und heutige Vernetzung der Waldflächen analysiert, die Umweltbedingungen in historisch-alten Wäldern und neu etablierten Wäldern verglichen und der Umfang und die Bezahlung der Aussterbeschulden und der Kolonisierungskredite ermittelt. Die Arbeit zeigt, dass historische Landnutzungsveränderungen die heutige Artenvielfalt noch immer beeinflussen. Obwohl die heutigen Umweltbedingungen in historisch-alten und neu etablierten Wäldern vergleichbar waren, war die Gesamtartenzahl in historisch-alten Wäldern signifikant höher und in diesen Wäldern wurden insbesondere mehr Waldspezialisten und sich nur über kurze Enfernung ausbreitende Pflanzenarten gefunden. Die Unterschiede in den Artenzahlen sind vor allem auf einen Kolonisierungskredit in neu etablierten Wäldern zurückzuführen, während die Aussterbeschulden in historisch-alten Wäldern weitgehend bezahlt wurden. Der Kolonisierungskredits war am höchsten in isoliert gelegenen Waldflächen und belief sich auf bis zu 9 Arten (im Mittel 4,7). Der Kolonisierungskredit in besser vernetzten und in direkt an historisch-alten Wäldern angrenzenden Flächen war deutlich geringer. In diesen Wäldern konnte eine Verringerung des Kolonisierungskredites von im Mittel 2,7 zu 1,5 Arten über die letzten sechs Jahrzehnte nachgewiesen werden. KW - ecology KW - plant science KW - extinction debt KW - colonization credit KW - species richness KW - land use history KW - Ökologie KW - Pflanzenwissenschaften KW - Botanik KW - Aussterbeschuld KW - Einwanderungskredit KW - Biodiversität KW - Landnutzungshistorie Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-439398 ER - TY - RPRT A1 - Marcus, Jan A1 - Siedler, Thomas A1 - Ziebarth, Nicolas R. T1 - The Long-Run Effects of Sports Club Vouchers for Primary School Children T2 - CEPA Discussion Papers N2 - Starting in 2009, the German state of Saxony distributed sports club membership vouchers among all 33,000 third graders in the state. The policy’s objective was to encourage them to develop a long-term habit of exercising. In 2018, we carried out a large register-based survey among several cohorts in Saxony and two neighboring states. Our difference-in-differences estimations show that, even after a decade, awareness of the voucher program was significantly higher in the treatment group. We also find that youth received and redeemed the vouchers. However, we do not find significant short- or long-term effects on sports club membership, physical activity, overweightness, or motor skills. T3 - CEPA Discussion Papers - 34 KW - physical activity KW - voucher KW - primary school KW - obesity KW - habit formation KW - objective health measures KW - school health examinations KW - windfall gains KW - crowding out KW - taxpayer subsidies Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-508978 SN - 2628-653X IS - 34 ER - TY - RPRT A1 - Caliendo, Marco A1 - Künn, Steffen A1 - Mahlstedt, Robert T1 - The Intended and Unintended Effects of Promoting Labor Market Mobility T2 - CEPA Discussion Papers N2 - Subsidizing the geographical mobility of unemployed workers may improve welfare by relaxing their financial constraints and allowing them to find jobs in more prosperous regions. We exploit regional variation in the promotion of mobility programs along administrative borders of German employment agency districts to investigate the causal effect of offering such financial incentives on the job search behavior and labor market integration of unemployed workers. We show that promoting mobility – as intended – causes job seekers to increase their search radius, apply for and accept distant jobs. At the same time, local job search is reduced with adverse consequences for reemployment and earnings. These unintended negative effects are provoked by spatial search frictions. Overall, the unconditional provision of mobility programs harms the welfare of unemployed job seekers. T3 - CEPA Discussion Papers - 42 KW - Job Search KW - Active Labor Market Policy KW - Labor Market Mobility KW - Unintended Consequence KW - Search Frictions Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-535229 SN - 2628-653X ER - TY - JOUR A1 - Endriss, Cornelia A1 - Hinterwimmer, Stefan T1 - The influence of tense in adverbial quantification JF - Interdisciplinary studies on information structure : ISIS ; working papers of the SFB 632 N2 - We argue that there is a crucial difference between determiner and adverbial quantification. Following Herburger [2000] and von Fintel [1994], we assume that determiner quantifiers quantify over individuals and adverbial quantifiers over eventualities. While it is usually assumed that the semantics of sentences with determiner quantifiers and those with adverbial quantifiers basically come out the same, we will show by way of new data that quantification over events is more restricted than quantification over individuals. This is because eventualities in contrast to individuals have to be located in time which is done using contextual information according to a pragmatic resolution strategy. If the contextual information and the tense information given in the respective sentence contradict each other, the sentence is uninterpretable. We conclude that this is the reason why in these cases adverbial quantification, i.e. quantification over eventualities, is impossible whereas quantification over individuals is fine. KW - Adverbial Quantification KW - Covert Variables KW - Domain Restriction KW - Quantificational Variability Y1 - 2004 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-8409 SN - 1866-4725 SN - 1614-4708 IS - 1 SP - 121 EP - 151 ER - TY - RPRT A1 - Caliendo, Marco A1 - Kritikos, Alexander A1 - Stier, Claudia T1 - The Influence of Start-up Motivation on Entrepreneurial Performance T2 - CEPA Discussion Papers N2 - Predicting entrepreneurial development based on individual and business-related characteristics is a key objective of entrepreneurship research. In this context, we investigate whether the motives of becoming an entrepreneur influence the subsequent entrepreneurial development. In our analysis, we examine a broad range of business outcomes including survival and income, as well as job creation, expansion and innovation activities for up to 40 months after business formation. Using self-determination theory as conceptual background, we aggregate the start-up motives into a continuous motivational index. We show – based on a unique dataset of German start-ups from unemployment and non-unemployment – that the later business performance is better, the higher they score on this index. Effects are particularly strong for growth oriented outcomes like innovation and expansion activities. In a next step, we examine three underlying motivational categories that we term opportunity, career ambition, and necessity. We show that individuals driven by opportunity motives perform better in terms of innovation and business expansion activities, while career ambition is positively associated with survival, income, and the probability of hiring employees. All effects are robust to the inclusion of a large battery of covariates that are proven to be important determinants of entrepreneurial performance. T3 - CEPA Discussion Papers - 59 KW - Entrepreneurship KW - Push and Pull Theories KW - Start-up Motivation KW - Survival KW - Job Creation KW - Firm Growth KW - Innovation Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-571152 SN - 2628-653X IS - 59 ER - TY - CHAP A1 - Krtička, Jiri A1 - Puls, Joachim A1 - Kubát, Jiří T1 - The influence of clumping on predicted O star wind parameters N2 - We study the influence of clumping on the predicted wind structure of O-type stars. For this purpose we artificially include clumping into our stationary wind models. When the clumps are assumed to be optically thin, the radiative line force increases compared to corresponding unclumped models, with a similar effect on either the mass-loss rate or the terminal velocity (depending on the onset of clumping). Optically thick clumps, alternatively, might be able to decrease the radiative force. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17969 ER - TY - THES A1 - Ketzer, Laura T1 - The impact of stellar activity evolution on atmospheric mass loss of young exoplanets T1 - Der Einfluss der stellaren Aktivitätsentwicklung auf den atmosphärischen Massenverlust von jungen Exoplaneten N2 - The increasing number of known exoplanets raises questions about their demographics and the mechanisms that shape planets into how we observe them today. Young planets in close-in orbits are exposed to harsh environments due to the host star being magnetically highly active, which results in high X-ray and extreme UV fluxes impinging on the planet. Prolonged exposure to this intense photoionizing radiation can cause planetary atmospheres to heat up, expand and escape into space via a hydrodynamic escape process known as photoevaporation. For super-Earth and sub-Neptune-type planets, this can even lead to the complete erosion of their primordial gaseous atmospheres. A factor of interest for this particular mass-loss process is the activity evolution of the host star. Stellar rotation, which drives the dynamo and with it the magnetic activity of a star, changes significantly over the stellar lifetime. This strongly affects the amount of high-energy radiation received by a planet as stars age. At a young age, planets still host warm and extended envelopes, making them particularly susceptible to atmospheric evaporation. Especially in the first gigayear, when X-ray and UV levels can be 100 - 10,000 times higher than for the present-day sun, the characteristics of the host star and the detailed evolution of its high-energy emission are of importance. In this thesis, I study the impact of stellar activity evolution on the high-energy-induced atmospheric mass loss of young exoplanets. The PLATYPOS code was developed as part of this thesis to calculate photoevaporative mass-loss rates over time. The code, which couples parameterized planetary mass-radius relations with an analytical hydrodynamic escape model, was used, together with Chandra and eROSITA X-ray observations, to investigate the future mass loss of the two young multiplanet systems V1298 Tau and K2-198. Further, in a numerical ensemble study, the effect of a realistic spread of activity tracks on the small-planet radius gap was investigated for the first time. The works in this thesis show that for individual systems, in particular if planetary masses are unconstrained, the difference between a young host star following a low-activity track vs. a high-activity one can have major implications: the exact shape of the activity evolution can determine whether a planet can hold on to some of its atmosphere, or completely loses its envelope, leaving only the bare rocky core behind. For an ensemble of simulated planets, an observationally-motivated distribution of activity tracks does not substantially change the final radius distribution at ages of several gigayears. My simulations indicate that the overall shape and slope of the resulting small-planet radius gap is not significantly affected by the spread in stellar activity tracks. However, it can account for a certain scattering or fuzziness observed in and around the radius gap of the observed exoplanet population. N2 - Die steigende Anzahl bekannter Exoplaneten wirft Fragen zu ihrer Demografie und den Mechanismen auf, die Planeten in ihre heutige beobachtete Form bringen. Junge Planeten, die sehr nah um ihren Wirtsstern kreisen, sind extremen Umgebungen ausgesetzt, da der Stern eine hohe magnetische Aktivität aufweist. Das führt wiederum dazu, dass der Planet einer enormen Röntgen- und Extrem-UV-Strahlung ausgesetzt ist. Ist der Planet über einen längeren Zeitraum dieser intensiven photoionisierenden Strahlung ausgesetzt, kann dies dazu führen, dass Planetenatmosphären sich aufheizen, ausdehnen und durch einen hydrodynamischen Entweichungsprozess namens Photoevaporation ins All entweichen, sozusagen verdampfen. Bei Planeten, in der Größenordnung von Super-Erden und Sub-Neptunen, kann dies sogar zur vollständigen Erosion ihrer Ur-Atmosphären führen. Ein interessanter Faktor, der für diesen Massenverlustprozess eine Rolle spielt, ist die Aktivitätsentwicklung des Wirtssterns. Die Rotation eines Sterns, die den Dynamo und damit die magnetische Aktivität antreibt, ändert sich im Laufe der Lebensdauer eines Sterns erheblich. Dies hat einen starken Einfluss auf die Menge der hochenergetischen Strahlung, den ein Planet mit zunehmendem Alter des Sterns empfängt. In jungen Jahren besitzen Planeten noch warme und ausgedehnte Hüllen, was sie besonders anfällig für atmosphärische Verdunstung macht. Insbesondere in den ersten Gigajahren, wenn die Röntgen- und UV-Strahlung 100 - 10,000 Mal höher sein kann als bei der heutigen Sonne, sind die Eigenschaften des Wirtssterns und die detaillierte Entwicklung seiner hochenergetischen Emission von Bedeutung. In dieser Arbeit untersuche ich die Auswirkungen der Entwicklung der stellaren Aktivität auf den durch hochenergetische Strahlung verursachten atmosphärischen Massenverlust junger Exoplaneten. Der PLATYPOS-Code wurde im Rahmen dieser Arbeit entwickelt, um die photoevaporativen Massenverlustraten für verschiedene stellare Alter zu berechnen. Der Code verknüpft parametrisierte Planetenmasse-Radius-Beziehungen mit einem analytischen Modell für den hydrodynamischen Massenverlust. Er wurde zusammen mit Chandra- und eROSITA-Röntgenbeobachtungen dazu verwendet, den zukünftigen Massenverlust der beiden jungen Mehrplanetensysteme V1298 Tau und K2-198 zu untersuchen. Darüber hinaus wurde in einer numerischen Ensemblestudie erstmals der Effekt einer realistischen Verteilung von stellaren Aktivitäts-Tracks auf das sogenannte Radius-Tal bei kleinen Planeten untersucht. Die Arbeiten in dieser Dissertation zeigen, dass für einzelne Systeme, insbesondere wenn die Planetenmassen unbestimmt sind, der Unterschied zwischen einem jungen Wirtsstern, der einem Track mit niedriger Aktivität gegenüber einem solchen mit hoher Aktivität folgt, gravierende Auswirkungen haben kann: Die genaue Form der Aktivitätsentwicklung kann darüber entscheiden, ob ein Planet einen Teil seiner Atmosphäre behält oder seine Hülle vollständig verliert und nur den nackten Gesteinskern behält. Für ein Ensemble von simulierten Planeten ändert eine durch Beobachtungen motivierte Verteilung von Aktivitäts-Tracks die endgültige Radiusverteilung der Planeten nach mehreren Gigajahren nicht wesentlich. Meine Simulationen deuten darauf hin, dass die Form und Steigung des sich ergebenden Radius-Tals bei Kleinplaneten nicht wesentlich von der Streuung der stellaren Aktivitäts-Tracks beeinflusst wird. Eine gewisse Streuung oder Unschärfe im Radius-Tal der beobachteten Exoplanetenpopulation kann damit allerdings durchaus erklärt werden. KW - Exoplaneten KW - star-planet interaction KW - stellar physics KW - exoplanets KW - exoplanet atmospheres KW - Sternphysik KW - Stern-Planeten-Wechselwirkung KW - Exoplanetenatmosphären Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-626819 ER - TY - CHAP A1 - Hirschi, Raphael T1 - The impact of reduced mass loss rates on the evolution of massive stars N2 - Mass loss is a very important aspect of the life of massive stars. After briefly reviewing its importance, we discuss the impact of the recently proposed downward revision of mass loss rates due to clumping (difficulty to form Wolf-Rayet stars and production of critically rotating stars). Although a small reduction might be allowed, large reduction factors around ten are disfavoured. We then discuss the possibility of significant mass loss at very low metallicity due to stars reaching break-up velocities and especially due to the metal enrichment of the surface of the star via rotational and convective mixing. This significant mass loss may help the first very massive stars avoid the fate of pair-creation supernova, the chemical signature of which is not observed in extremely metal poor stars. The chemical composition of the very low metallicity winds is very similar to that of the most metal poor star known to date, HE1327-2326 and offer an interesting explanation for the origin of the metals in this star. We also discuss the importance of mass loss in the context of long and soft gamma-ray bursts and pair-creation supernovae. Finally, we would like to stress that mass loss in cooler parts of the HR-diagram (luminous blue variable and yellow and red supergiant stages) are much more uncertain than in the hot part. More work needs to be done in these areas to better constrain the evolution of the most massive stars. Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-17616 ER - TY - JOUR A1 - Jafarnezhadgero, Amir Ali A1 - Noroozi, Raha A1 - Fakhri Mirzanag, Ehsan A1 - Granacher, Urs A1 - de Souza Castelo Oliveira, Anderson T1 - The Impact of COVID-19 and Muscle Fatigue on Cardiorespiratory Fitness and Running Kinetics in Female Recreational Runners JF - Frontiers in Physiology N2 - Background: There is evidence that fully recovered COVID-19 patients usually resume physical exercise, but do not perform at the same intensity level performed prior to infection. The aim of this study was to evaluate the impact of COVID-19 infection and recovery as well as muscle fatigue on cardiorespiratory fitness and running biomechanics in female recreational runners. Methods: Twenty-eight females were divided into a group of hospitalized and recovered COVID-19 patients (COV, n = 14, at least 14 days following recovery) and a group of healthy age-matched controls (CTR, n = 14). Ground reaction forces from stepping on a force plate while barefoot overground running at 3.3 m/s was measured before and after a fatiguing protocol. The fatigue protocol consisted of incrementally increasing running speed until reaching a score of 13 on the 6–20 Borg scale, followed by steady-state running until exhaustion. The effects of group and fatigue were assessed for steady-state running duration, steady-state running speed, ground contact time, vertical instantaneous loading rate and peak propulsion force. Results: COV runners completed only 56% of the running time achieved by the CTR (p < 0.0001), and at a 26% slower steady-state running speed (p < 0.0001). There were fatigue-related reductions in loading rate (p = 0.004) without group differences. Increased ground contact time (p = 0.002) and reduced peak propulsion force (p = 0.005) were found for COV when compared to CTR. Conclusion: Our results suggest that female runners who recovered from COVID-19 showed compromised running endurance and altered running kinetics in the form of longer stance periods and weaker propulsion forces. More research is needed in this area using larger sample sizes to confirm our study findings. KW - hospitalization KW - running mechanics KW - ground reaction forces KW - virus infection KW - COVID-19 Y1 - 2022 U6 - https://doi.org/10.3389/fphys.2022.942589 SN - 1664-042X VL - 13 SP - 1 EP - 10 PB - Frontiers CY - Lausanne, Schweiz ER - TY - JOUR A1 - Ogunkola, Moses Olalekan A1 - Guiraudie-Capraz, Gaelle A1 - Féron, François A1 - Leimkühler, Silke T1 - The Human Mercaptopyruvate Sulfurtransferase TUM1 Is Involved in Moco Biosynthesis, Cytosolic tRNA Thiolation and Cellular Bioenergetics in Human Embryonic Kidney Cells JF - Biomolecules N2 - Sulfur is an important element that is incorporated into many biomolecules in humans. The incorporation and transfer of sulfur into biomolecules is, however, facilitated by a series of different sulfurtransferases. Among these sulfurtransferases is the human mercaptopyruvate sulfurtransferase (MPST) also designated as tRNA thiouridine modification protein (TUM1). The role of the human TUM1 protein has been suggested in a wide range of physiological processes in the cell among which are but not limited to involvement in Molybdenum cofactor (Moco) biosynthesis, cytosolic tRNA thiolation and generation of H2S as signaling molecule both in mitochondria and the cytosol. Previous interaction studies showed that TUM1 interacts with the L-cysteine desulfurase NFS1 and the Molybdenum cofactor biosynthesis protein 3 (MOCS3). Here, we show the roles of TUM1 in human cells using CRISPR/Cas9 genetically modified Human Embryonic Kidney cells. Here, we show that TUM1 is involved in the sulfur transfer for Molybdenum cofactor synthesis and tRNA thiomodification by spectrophotometric measurement of the activity of sulfite oxidase and liquid chromatography quantification of the level of sulfur-modified tRNA. Further, we show that TUM1 has a role in hydrogen sulfide production and cellular bioenergetics. KW - Moco biosynthesis KW - sulfite oxidase KW - cytosolic tRNA thiolation KW - 5-methoxycarbonylmethyl-2-thiouridine KW - H2S biosynthesis KW - cellular bioenergetics Y1 - 2023 U6 - https://doi.org/10.3390/biom13010144 SN - 2218-273X VL - 13 SP - 1 EP - 23 PB - MDPI CY - Basel, Schweiz ET - 1 ER - TY - THES A1 - Kerutt, Josephine Victoria T1 - The high-redshift voyage of Lyman alpha and Lyman continuum emission as told by MUSE T1 - Die Reise der Lyman alpha- und Lyman Kontinuumsemission bei hoher Rotverschiebung erzählt von MUSE N2 - Most of the matter in the universe consists of hydrogen. The hydrogen in the intergalactic medium (IGM), the matter between the galaxies, underwent a change of its ionisation state at the epoch of reionisation, at a redshift roughly between 6>z>10, or ~10^8 years after the Big Bang. At this time, the mostly neutral hydrogen in the IGM was ionised but the source of the responsible hydrogen ionising emission remains unclear. In this thesis I discuss the most likely candidates for the emission of this ionising radiation, which are a type of galaxy called Lyman alpha emitters (LAEs). As implied by their name, they emit Lyman alpha radiation, produced after a hydrogen atom has been ionised and recombines with a free electron. The ionising radiation itself (also called Lyman continuum emission) which is needed for this process inside the LAEs could also be responsible for ionising the IGM around those galaxies at the epoch of reionisation, given that enough Lyman continuum escapes. Through this mechanism, Lyman alpha and Lyman continuum radiation are closely linked and are both studied to better understand the properties of high redshift galaxies and the reionisation state of the universe. Before I can analyse their Lyman alpha emission lines and the escape of Lyman continuum emission from them, the first step is the detection and correct classification of LAEs in integral field spectroscopic data, specifically taken with the Multi-Unit Spectroscopic Explorer (MUSE). After detecting emission line objects in the MUSE data, the task of classifying them and determining their redshift is performed with the graphical user interface QtClassify, which I developed during the work on this thesis. It uses the strength of the combination of spectroscopic and photometric information that integral field spectroscopy offers to enable the user to quickly identify the nature of the detected emission lines. The reliable classification of LAEs and determination of their redshifts is a crucial first step towards an analysis of their properties. Through radiative transfer processes, the properties of the neutral hydrogen clouds in and around LAEs are imprinted on the shape of the Lyman alpha line. Thus after identifying the LAEs in the MUSE data, I analyse the properties of the Lyman alpha emission line, such as the equivalent width (EW) distribution, the asymmetry and width of the line as well as the double peak fraction. I challenge the common method of displaying EW distributions as histograms without taking the limits of the survey into account and construct a more independent EW distribution function that better reflects the properties of the underlying population of galaxies. I illustrate this by comparing the fraction of high EW objects between the two surveys MUSE-Wide and MUSE-Deep, both consisting of MUSE pointings (each with the size of one square arcminute) of different depths. In the 60 MUSE-Wide fields of one hour exposure time I find a fraction of objects with extreme EWs above EW_0>240A of ~20%, while in the MUSE-Deep fields (9 fields with an exposure time of 10 hours and one with an exposure time of 31 hours) I find a fraction of only ~1%, which is due to the differences in the limiting line flux of the surveys. The highest EW I measure is EW_0 = 600.63 +- 110A, which hints at an unusual underlying stellar population, possibly with a very low metallicity. With the knowledge of the redshifts and positions of the LAEs detected in the MUSE-Wide survey, I also look for Lyman continuum emission coming from these galaxies and analyse the connection between Lyman continuum emission and Lyman alpha emission. I use ancillary Hubble Space Telescope (HST) broadband photometry in the bands that contain the Lyman continuum and find six Lyman continuum leaker candidates. To test whether the Lyman continuum emission of LAEs is coming only from those individual objects or the whole population, I select LAEs that are most promising for the detection of Lyman continuum emission, based on their rest-frame UV continuum and Lyman alpha line shape properties. After this selection, I stack the broadband data of the resulting sample and detect a signal in Lyman continuum with a significance of S/N = 5.5, pointing towards a Lyman continuum escape fraction of ~80%. If the signal is reliable, it strongly favours LAEs as the providers of the hydrogen ionising emission at the epoch of reionisation and beyond. N2 - Die Materie zwischen den Galaxien im Universum, das sogenannte intergalaktische Medium, besteht zum größten Teil aus Wasserstoff, welcher sich zusammensetzt aus einem Proton und einem Elektron. Etwa ~10^8 Jahre nach dem Urknall änderte sich der Ionisationszustand des Wasserstoffs im intergalaktischen Medium. Durch Strahlung wurden Proton und Elektronen getrennt, der Wasserstoff wurde ionisiert. Die Strahlung mit der nötigen Energie um Wasserstoff zu ionisieren nennt man Lyman Kontinuum Strahlung. Woher diese stammt ist bis heute eine offene Frage. In der vorliegenden Arbeit diskutiere ich die wahrscheinlichsten Kandidaten für die Emission dieser ionisierenden Strahlung: die Lyman alpha Emitter (LAE), eine Gruppe von Galaxien die man im frühen Universum antrifft. Hat nämlich ein Lyman Kontinuum Photon ein Wasserstoffatom ionisiert, kommt es häufig vor, dass sich Proton und Elektron wieder zu einem neutralen Wasserstoffatom verbinden. Bei diesem Prozess wird dann ein Lyman alpha Photon freigesetzt, was den LAE ihren Namen gibt. Da wir in den Spektren dieser Galaxien die Lyman alpha Photonen beobachten können, deren Voraussetzung die Existenz von Lyman Kontinuum Emission in der Galaxie ist, liegt es nahe anzunehmen, dass die Lyman Kontinuum Emission auch in das intergalaktische Medium vordringen kann um den Wasserstoff dort ebenfalls zu ionisieren. Durch diesen Mechanismus sind Lyman alpha und Lyman-Kontinuumsstrahlung eng miteinander verbunden und werden in dieser Arbeit beide untersucht, um die Eigenschaften von Galaxien im frühen Universum und den Zustand des Wasserstoffs im intergalaktischen Medium besser zu verstehen. Der erste Schritt ist jedoch die Detektion und korrekte Klassifizierung von LAE. Dafür benutze ich Daten des Multi-Unit Spectroscopic Explorer (MUSE), ein Instrument mit dem Beobachtungen möglich sind, die zwei räumliche Dimensionen mit einer spektralen Dimension verbinden. Somit ist in jedem Pixel der Daten ein Spektrum zur Verfügung, in dem nach Emissionslinien gesucht werden kann. Nach der Detektion von Emissionslinien in den MUSE-Daten wird die Aufgabe der Klassifizierung von der grafischen Benutzeroberfläche QtClassify unterstützt, die ich in dieser Arbeit entwickelt habe. Sie bietet dem Benutzer eine schnelle und übersichtliche Identifizierung der gefundenen Emissionslinien, was einen entscheidenden ersten Schritt zur Analyse der Eigenschaften der LAE darstellt. Da Lyman alpha Photonen in neutralem Wasserstoff, der im Inneren von Galaxien in Gaswolken vorkommt, gestreut wird, verändert sich die Form der Lyman alpha Emissionslinie im Spektrum. Nachdem also die LAE mit Hilfe von QtClassify identifiziert werden konnten, analysiere ich die Lyman alpha Linie hinsichtlich ihrer Breite, ihrer Symmetrie und ihrer Stärke und suche nach Doppellinien, die Hinweise auf die Kinematik der Wasserstoff Gaswolken geben. Besonders wichtig dabei ist die Stärke der Linie im Vergleich zum restlichen Spektrum, die sogenannte Äquivalentbreite. Dabei zeige ich, dass die übliche Methode die Verteilung der Äquivalentbreiten als Histogramme darzustellen ohne die Detektionsgrenzen der Beobachtungen miteinzubeziehen keine Aussage über die Eigenschaften der LAE, sondern lediglich über die Grenzen der Beobachtungen treffen. Daher konstruiere ich eine unabhängigere Verteilungsfunktion, die diese Grenzen mit einbezieht. Ich verdeutliche dies durch einen Vergleich des Anteils von Objekten mit hoher Äquivalentbreite in zwei verschiedenen Datensätzen, die auf Beobachtungen mit unterschiedlicher Belichtungszeit beruhen. Dabei finde ich in dem Datensatz mit der kürzeren Belichtungszeit einen Anteil von ~20% an Objekten mit hohen Äquivalentbreiten (über >240A) und nur ~1% im Datensatz mit der zehnfach längeren Belichtungszeit obwohl die Eigenschaften der LAE gleich sind. Zudem finde ich eine Galaxie mit einer Äquivalentbreite der Lyman alpha Linie von 600 +- 110A, was auf eine ungewöhnliche Sternpopulation hindeutet. Als letzten Schritt suche ich in den klassifizierten LAE nach Lyman Kontinuum, was für die Ionisierung des Wasserstoffs im intergalaktischen Medium verantwortlich ist, und untersuche den Zusammenhang zwischen der Lyman alpha und der Lyman Kontinuumsstrahlung. Um das Lyman Kontinuum detektieren zu können benutze ich Daten des Hubble-Weltraumteleskops (HST) und finde sechs Lyman Kontinuum Kandidaten unter den LAE. Um zu testen ob die Lyman Kontinuumsstrahlung lediglich von diesen Objekten ausgeht oder auch im der Gesamtheit der LAE zu finden ist, addiere ich die Daten des HST und finde ein Signal, was darauf hindeutet, dass ~80% der Lyman Kontinuumsstrahlung aus den Galaxien entkommen und in das intergalaktische Medium vordringen kann. Wenn das gefundene Signal zuverlässig ist deutet es darauf hin, dass in der Tat LAE für die Ionisierung des Wasserstoffs im Universum verantwortlich sein könnten. KW - astronomy KW - LAEs KW - reionization KW - Lyman alpha KW - Lyman continuum KW - VLT/MUSE KW - emission line classification KW - QtClassify KW - LAEs KW - Lyman alpha KW - Lyman Kontinuum KW - QtClassify KW - VLT/MUSE KW - Astronomie KW - Emissionslinienklassifikation KW - Reionisierung Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-478816 ER - TY - CHAP A1 - Demske, Ulrike ED - Szczepaniak, Renata ED - Flick, Johanna T1 - The grammaticalization of the definite article in German BT - from demonstratives to weak definites T2 - Walking on the Grammaticalization Path of the Definite Article in German: Functional Main and Side Roads N2 - The present paper looks into the grammaticalization of the definite article in the history of German. Starting with the well-known emergence of the definite article from a demonstrative pronoun over the course of Old High German (750–1050), I will consider the rise of so-called weak definites in Early New High German (1350–1650) as a new piece of evidence for the grammaticalization process. Here, the subclass of possessive weak definites is of particular interest for the grammaticalization of the definite article in German, because of a word order change affecting the position of possessor phrases. As soon as the possessor systematically follows the head noun (except for proper names), we observe three alternatives for the prenominal determiner slot: it may remain empty, or it may be filled either by the indefinite or the definite article in Early New High German. In Present-Day German, the definite article is used in the unmarked case, thus pointing to a second stage in the grammaticalization process of the definite article in German, which has so far not been acknowledged in the literature. KW - grammaticalization KW - definite article KW - weak definites KW - Old High German KW - Early New High German KW - Present-Day German Y1 - 2020 SN - 978-9-027204943 SN - 978-9-027261564 SP - 43 EP - 73 PB - John Benjamins Publishing Company CY - Amsterdam ER -