TY - GEN A1 - Cao, Xianyong A1 - Herzschuh, Ulrike A1 - Ni, Jian A1 - Zhao, Yan A1 - Böhmer, Thomas T1 - Spatial and temporal distributions of major tree taxa in eastern continental Asia during the last 22,000 years T2 - The Holocene N2 - This study investigates the spatial and temporal distributions of 14 key arboreal taxa and their driving forces during the last 22,000 calendar years before ad 1950 (kyr BP) using a taxonomically harmonized and temporally standardized fossil pollen dataset with a 500-year resolution from the eastern part of continental Asia. Logistic regression was used to estimate pollen abundance thresholds for vegetation occurrence (presence or dominance), based on modern pollen data and present ranges of 14 taxa in China. Our investigation reveals marked changes in spatial and temporal distributions of the major arboreal taxa. The thermophilous (Castanea, Castanopsis, Cyclobalanopsis, Fagus, Pterocarya) and eurythermal (Juglans, Quercus, Tilia, Ulmus) broadleaved tree taxa were restricted to the current tropical or subtropical areas of China during the Last Glacial Maximum (LGM) and spread northward since c. 14.5 kyr BP. Betula and conifer taxa (Abies, Picea, Pinus), in contrast, retained a wider distribution during the LGM and showed no distinct expansion direction during the Late Glacial. Since the late mid-Holocene, the abundance but not the spatial extent of most trees decreased. The changes in spatial and temporal distributions for the 14 taxa are a reflection of climate changes, in particular monsoonal moisture, and, in the late Holocene, human impact. The post-LGM expansion patterns in eastern continental China seem to be different from those reported for Europe and North America, for example, the westward spread for eurythermal broadleaved taxa. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 417 KW - China KW - Holocene KW - Last Glacial Maximum KW - pollen mapping KW - vegetation expansion Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-404176 VL - 25 IS - 1 ER - TY - GEN A1 - Liu, W. A1 - Tkachov, R. A1 - Komber, H. A1 - Senkovskyy, V. A1 - Schubert, M. A1 - Wei, Z. A1 - Facchetti, A. A1 - Neher, Dieter A1 - Kiriy, A. T1 - Chain-growth polycondensation of perylene diimide-based copolymers BT - a new route to regio-regular perylene diimide-based acceptors for all-polymer solar cells and n-type transistors N2 - Herein, we report the chain-growth tin-free room temperature polymerization method to synthesize n-type perylene diimide-dithiophene-based conjugated polymers (PPDIT2s) suitable for solar cell and transistor applications. The palladium/electron-rich tri-tert-butylphosphine catalyst is effective to enable the chain-growth polymerization of anion-radical monomer Br-TPDIT-Br/Zn to PPDIT2 with a molecular weight up to Mw ≈ 50 kg mol−1 and moderate polydispersity. This is the second example of the polymerization of unusual anion-radical aromatic complexes formed in a reaction of active Zn and electron-deficient diimide-based aryl halides. As such, the discovered polymerization method is not a specific reactivity feature of the naphthalene-diimide derivatives but is rather a general polymerization tool. This is an important finding, given the significantly higher maximum external quantum efficiency that can be reached with PDI-based copolymers (32–45%) in all-polymer solar cells compared to NDI-based materials (15–30%). Our studies revealed that PPDIT2 synthesized by the new method and the previously published polymer prepared by step-growth Stille polycondensation show similar electron mobility and all-polymer solar cell performance. At the same time, the polymerization reported herein has several technological advantages as it proceeds relatively fast at room temperature and does not involve toxic tin-based compounds. Because several chain-growth polymerization reactions are well-suited for the preparation of well-defined multi-functional polymer architectures, the next target is to explore the utility of the discovered polymerization in the synthesis of end-functionalized polymers and block copolymers. Such materials would be helpful to improve the nanoscale morphology of polymer blends in all-polymer solar cells. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 273 Y1 - 2014 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-98724 ER - TY - GEN A1 - Bondü, Rebecca A1 - Scheithauer, Herbert T1 - Leaking and death-threats by students BT - a study in German schools T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Leaking comprises observable behavior or statements that signal intentions of committing a violent offense and is considered an important warning sign for school shootings. School staff who are confronted with leaking have to assess its seriousness and react appropriately - a difficult task, because knowledge about leaking is sparse. The present study, therefore, examined how frequently leaking occurs in schools and how teachers identify leaking and respond to it. To achieve this aim, we informed teachers from eight schools in Germany about the definition of leaking and other warning signs and risk factors for school shootings in a one-hour information session. Teachers were then asked to report cases of leaking over a six- to nine-month period and to answer a questionnaire on leaking and its treatment after the information session and six to nine months later. Our results suggest that leaking is a relevant problem in German schools. Teachers mostly rated the information session positively and benefited in several aspects (e.g. reported more perceived courses of action or improved knowledge about leaking), but also expressed a constant need for support. Our findings highlight teachers' needs for further support and training and may be used in the planning of prevention measures for school shootings. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 388 KW - death-threats KW - leaking KW - prevention KW - school shooting KW - violence in schools Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-404121 IS - 388 ER - TY - GEN A1 - Bondü, Rebecca A1 - Beier, Sophia T1 - Two of a kind? BT - differences and similarities of attacks in schools and in institutes of higher education T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - School attacks are attracting increasing attention in aggression research. Recent systematic analyses provided new insights into offense and offender characteristics. Less is known about attacks in institutes of higher education (e.g., universities). It is therefore questionable whether the term “school attack” should be limited to institutions of general education or could be extended to institutions of higher education. Scientific literature is divided in distinguishing or unifying these two groups and reports similarities as well as differences. We researched 232 school attacks and 45 attacks in institutes of higher education throughout the world and conducted systematic comparisons between the two groups. The analyses yielded differences in offender (e.g., age, migration background) and offense characteristics (e.g., weapons, suicide rates), and some similarities (e.g., gender). Most differences can apparently be accounted for by offenders’ age and situational influences. We discuss the implications of our findings for future research and the development of preventative measures. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 391 KW - school attack KW - IHE attack KW - rampage KW - higher education KW - characteristics KW - prevention Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-404199 IS - 391 ER - TY - GEN A1 - Tian, Fang A1 - Herzschuh, Ulrike A1 - Mischke, Steffen A1 - Schlütz, Frank T1 - What drives the recent intensified vegetation degradation in Mongolia BT - Climate change or human activity? T2 - The Holocene N2 - This study examines the course and driving forces of recent vegetation change in the Mongolian steppe. A sediment core covering the last 55years from a small closed-basin lake in central Mongolia was analyzed for its multi-proxy record at annual resolution. Pollen analysis shows that highest abundances of planted Poaceae and highest vegetation diversity occurred during 1977-1992, reflecting agricultural development in the lake area. A decrease in diversity and an increase in Artemisia abundance after 1992 indicate enhanced vegetation degradation in recent times, most probably because of overgrazing and farmland abandonment. Human impact is the main factor for the vegetation degradation within the past decades as revealed by a series of redundancy analyses, while climate change and soil erosion play subordinate roles. High Pediastrum (a green algae) influx, high atomic total organic carbon/total nitrogen (TOC/TN) ratios, abundant coarse detrital grains, and the decrease of C-13(org) and N-15 since about 1977 but particularly after 1992 indicate that abundant terrestrial organic matter and nutrients were transported into the lake and caused lake eutrophication, presumably because of intensified land use. Thus, we infer that the transition to a market economy in Mongolia since the early 1990s not only caused dramatic vegetation degradation but also affected the lake ecosystem through anthropogenic changes in the catchment area. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 418 KW - central Mongolia KW - grain size KW - human impact KW - lake eutrophication KW - pollen KW - vegetation degradation Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-404201 ER - TY - GEN A1 - Hägele, Claudia A1 - Schlagenhauf, Florian A1 - Rapp, Michael A. A1 - Sterzer, Philipp A1 - Beck, Anne A1 - Bermpohl, Felix A1 - Stoy, Meline A1 - Ströhle, Andreas A1 - Wittchen, Hans-Ulrich A1 - Dolan, Raymond J. A1 - Heinz, Andreas T1 - Dimensional psychiatry BT - reward dysfunction and depressive mood across psychiatric disorders T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - A dimensional approach in psychiatry aims to identify core mechanisms of mental disorders across nosological boundaries. We compared anticipation of reward between major psychiatric disorders, and investigated whether reward anticipation is impaired in several mental disorders and whether there is a common psychopathological correlate (negative mood) of such an impairment. We used functional magnetic resonance imaging (fMRI) and a monetary incentive delay (MID) task to study the functional correlates of reward anticipation across major psychiatric disorders in 184 subjects, with the diagnoses of alcohol dependence (n = 26), schizophrenia (n = 44), major depressive disorder (MDD, n = 24), bipolar disorder (acute manic episode, n = 13), attention deficit/hyperactivity disorder (ADHD, n = 23), and healthy controls (n = 54). Subjects' individual Beck Depression Inventory-and State-Trait Anxiety Inventory-scores were correlated with clusters showing significant activation during reward anticipation. During reward anticipation, we observed significant group differences in ventral striatal (VS) activation: patients with schizophrenia, alcohol dependence, and major depression showed significantly less ventral striatal activation compared to healthy controls. Depressive symptoms correlated with dysfunction in reward anticipation regardless of diagnostic entity. There was no significant correlation between anxiety symptoms and VS functional activation. Our findings demonstrate a neurobiological dysfunction related to reward prediction that transcended disorder categories and was related to measures of depressed mood. The findings underline the potential of a dimensional approach in psychiatry and strengthen the hypothesis that neurobiological research in psychiatric disorders can be targeted at core mechanisms that are likely to be implicated in a range of clinical entities. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 653 KW - dimensional KW - fMRI KW - reward system KW - ventral striatum KW - monetary incentive delay task KW - depressive symptoms Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-431064 SN - 1866-8364 IS - 653 SP - 331 EP - 341 ER - TY - GEN A1 - Friedel, Eva A1 - Schlagenhauf, Florian A1 - Beck, Anne A1 - Dolan, Raymond J. A1 - Huys, Quentin J. M. A1 - Rapp, Michael A. A1 - Heinz, Andreas T1 - The effects of life stress and neural learning signals on fluid intelligence T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Fluid intelligence (fluid IQ), defined as the capacity for rapid problem solving and behavioral adaptation, is known to be modulated by learning and experience. Both stressful life events (SLES) and neural correlates of learning [specifically, a key mediator of adaptive learning in the brain, namely the ventral striatal representation of prediction errors (PE)] have been shown to be associated with individual differences in fluid IQ. Here, we examine the interaction between adaptive learning signals (using a well-characterized probabilistic reversal learning task in combination with fMRI) and SLES on fluid IQ measures. We find that the correlation between ventral striatal BOLD PE and fluid IQ, which we have previously reported, is quantitatively modulated by the amount of reported SLES. Thus, after experiencing adversity, basic neuronal learning signatures appear to align more closely with a general measure of flexible learning (fluid IQ), a finding complementing studies on the effects of acute stress on learning. The results suggest that an understanding of the neurobiological correlates of trait variables like fluid IQ needs to take socioemotional influences such as chronic stress into account. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 621 KW - reinforcement learning KW - prediction error signal KW - ventral striatum KW - stress KW - intelligence Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-435140 SN - 1866-8372 IS - 621 SP - 35 EP - 43 ER -