TY - GEN A1 - Kashkarov, Egor B. A1 - Obrosov, Aleksei A1 - Sutygina, Alina N. A1 - Uludintceva, Elena A1 - Mitrofanov, Andrei A1 - Weiß, Sabine T1 - Hydrogen permeation, and mechanical and tribological behavior, of CrNx coatings deposited at various bias voltages on IN718 by direct current reactive sputtering T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - In the current work, the microstructure, hydrogen permeability, and properties of chromium nitride (CrNx) thin films deposited on the Inconel 718 superalloy using direct current reactive sputtering are investigated. The influence of the substrate bias voltage on the crystal structure, mechanical, and tribological properties before and after hydrogen exposure was studied. It was found that increasing the substrate bias voltage leads to densification of the coating. X-ray diffraction (XRD) results reveal a change from mixed fcc-CrN + hcp-Cr2N to the approximately stoichiometric hcp-Cr2N phase with increasing substrate bias confirmed by wavelength-dispersive X-ray spectroscopy (WDS). The texture coefficients of (113), (110), and (111) planes vary significantly with increasing substrate bias voltage. The hydrogen permeability was measured by gas-phase hydrogenation. The CrN coating deposited at 60 V with mixed c-CrN and (113) textured hcp-Cr2N phases exhibits the lowest hydrogen absorption at 873 K. It is suggested that the crystal orientation is only one parameter influencing the permeation resistance of the CrNx coating together with the film structure, the presence of mixing phases, and the packing density of the structure. After hydrogenation, the hardness increased for all coatings, which could be related to the formation of a Cr2O3 oxide film on the surface, as well as the defect formation after hydrogen loading. Tribological tests reveal that hydrogenation leads to a decrease of the friction coefficient by up to 40%. The lowest value of 0.25 +/- 0.02 was reached for the CrNx coating deposited at 60 V after hydrogenation. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1017 KW - CrNx coatings KW - Physical Vapour Deposition (PVD) KW - hydrogenation KW - Tribology KW - mechanical properties KW - X-ray diffraction Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459846 SN - 1866-8372 IS - 1017 ER - TY - GEN A1 - Prát, Tomáš A1 - Hajny ́, Jakub A1 - Grunewald, Wim A1 - Vasileva, Mina A1 - Molnár, Gergely A1 - Tejos, Ricardo A1 - Schmid, Markus A1 - Sauer, Michael A1 - Friml, Jiří T1 - WRKY23 is a component of the transcriptional network mediating auxin feedback on PIN polarity T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Auxin is unique among plant hormones due to its directional transport that is mediated by the polarly distributed PIN auxin transporters at the plasma membrane. The canalization hypothesis proposes that the auxin feedback on its polar flow is a crucial, plant-specific mechanism mediating multiple self-organizing developmental processes. Here, we used the auxin effect on the PIN polar localization in Arabidopsis thaliana roots as a proxy for the auxin feedback on the PIN polarity during canalization. We performed microarray experiments to find regulators of this process that act downstream of auxin. We identified genes that were transcriptionally regulated by auxin in an AXR3/IAA17-and ARF7/ARF19-dependent manner. Besides the known components of the PIN polarity, such as PID and PIP5K kinases, a number of potential new regulators were detected, among which the WRKY23 transcription factor, which was characterized in more detail. Gain-and loss-of-function mutants confirmed a role for WRKY23 in mediating the auxin effect on the PIN polarity. Accordingly, processes requiring auxin-mediated PIN polarity rearrangements, such as vascular tissue development during leaf venation, showed a higher WRKY23 expression and required the WRKY23 activity. Our results provide initial insights into the auxin transcriptional network acting upstream of PIN polarization and, potentially, canalization-mediated plant development. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1123 KW - apical-basal axis KW - arabidopsis-thaliana KW - root gravitropism KW - DNA-binding KW - gene-expression KW - transport KW - efflux KW - canalization KW - plants KW - phosphorylation Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446331 SN - 1866-8372 IS - 1123 ER - TY - GEN A1 - Lemaire, Olivier N. A1 - Infossi, Pascale A1 - Chaouche, Amine Ali A1 - Espinosa, Leon A1 - Leimkühler, Silke A1 - Giudici-Orticoni, Marie-Thérèse A1 - Méjean, Vincent A1 - Iobbi-Nivol, Chantal T1 - Small membranous proteins of the TorE/NapE family, crutches for cognate respiratory systems in Proteobacteria T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - In this report, we investigate small proteins involved in bacterial alternative respiratory systems that improve the enzymatic efficiency through better anchorage and multimerization of membrane components. Using the small protein TorE of the respiratory TMAO reductase system as a model, we discovered that TorE is part of a subfamily of small proteins that are present in proteobacteria in which they play a similar role for bacterial respiratory systems. We reveal by microscopy that, in Shewanella oneidensis MR1, alternative respiratory systems are evenly distributed in the membrane contrary to what has been described for Escherichia coli. Thus, the better efficiency of the respiratory systems observed in the presence of the small proteins is not due to a specific localization in the membrane, but rather to the formation of membranous complexes formed by TorE homologs with their c-type cytochrome partner protein. By an in vivo approach combining Clear Native electrophoresis and fluorescent translational fusions, we determined the 4: 4 stoichiometry of the complexes. In addition, mild solubilization of the cytochrome indicates that the presence of the small protein reinforces its anchoring to the membrane. Therefore, assembly of the complex induced by this small protein improves the efficiency of the respiratory system. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 933 KW - trimethylamine n-oxide KW - molybdenum cofactor biosynthesis KW - cytochrome bd oxidase KW - c-type cytochromes KW - escherichia-coli KW - swiss-model KW - native electrophoresis KW - mutational analysis KW - reductase KW - nitrate KW - microbiology KW - microbiology techniques Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459208 SN - 1866-8372 IS - 933 ER - TY - GEN A1 - Senczuk, Gabriele A1 - Havenstein, Katja A1 - Milana, Valentina A1 - Ripa, Chiara A1 - De Simone, Emanuela A1 - Tiedemann, Ralph A1 - Castiglia, Riccardo T1 - Spotlight on islands BT - on the origin and diversification of an ancient lineage of the Italian wall lizard Podarcis siculus in the western Pontine Islands T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Groups of proximate continental islands may conceal more tangled phylogeographic patterns than oceanic archipelagos as a consequence of repeated sea level changes, which allow populations to experience gene flow during periods of low sea level stands and isolation by vicariant mechanisms during periods of high sea level stands. Here, we describe for the first time an ancient and diverging lineage of the Italian wall lizard Podarcis siculus from the western Pontine Islands. We used nuclear and mitochondrial DNA sequences of 156 individuals with the aim of unraveling their phylogenetic position, while microsatellite loci were used to test several a priori insular biogeographic models of migration with empirical data. Our results suggest that the western Pontine populations colonized the islands early during their Pliocene volcanic formation, while populations from the eastern Pontine Islands seem to have been introduced recently. The inter-island genetic makeup indicates an important role of historical migration, probably due to glacial land bridges connecting islands followed by a recent vicariant mechanism of isolation. Moreover, the most supported migration model predicted higher gene flow among islands which are geographically arranged in parallel. Considering the threatened status of small insular endemic populations, we suggest this new evolutionarily independent unit be given priority in conservation efforts. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 991 KW - mitochondrial dna sequences KW - genetic diversity KW - haplotype reconstruction KW - evolutionary history KW - geological evolution KW - population structure KW - Tyrrhenian Sea KW - endemic lizard KW - genotype data KW - biogeography Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446360 SN - 1866-8372 IS - 991 ER - TY - GEN A1 - Pauly, Maren A1 - Helle, Gerhard A1 - Miramont, Cécile A1 - Büntgen, Ulf A1 - Treydte, Kerstin A1 - Reinig, Frederick A1 - Guibal, Frédéric A1 - Sivan, Olivier A1 - Heinrich, Ingo A1 - Riedel, Frank A1 - Kromer, Bernd A1 - Balanzategui, Daniel A1 - Wacker, Lukas A1 - Sookdeo, Adam Sookdeo A1 - Brauer, Achim T1 - Subfossil trees suggest enhanced Mediterranean hydroclimate variability at the onset of the Younger Dryas T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Nearly 13,000 years ago, the warming trend into the Holocene was sharply interrupted by a reversal to near glacial conditions. Climatic causes and ecological consequences of the Younger Dryas (YD) have been extensively studied, however proxy archives from the Mediterranean basin capturing this period are scarce and do not provide annual resolution. Here, we report a hydroclimatic reconstruction from stable isotopes (delta O-18, delta C-13) in subfossil pines from southern France. Growing before and during the transition period into the YD (12 900-12 600 cal BP), the trees provide an annually resolved, continuous sequence of atmospheric change. Isotopic signature of tree sourcewater (delta O-18(sw)) and estimates of relative air humidity were reconstructed as a proxy for variations in air mass origin and precipitation regime. We find a distinct increase in inter-annual variability of sourcewater isotopes (delta O-18(sw)), with three major downturn phases of increasing magnitude beginning at 12 740 cal BP. The observed variation most likely results from an amplified intensity of North Atlantic (low delta O-18(sw)) versus Mediterranean (high delta O-18(sw)) precipitation. This marked pattern of climate variability is not seen in records from higher latitudes and is likely a consequence of atmospheric circulation oscillations at the margin of the southward moving polar front. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1135 KW - annually laminated sediments KW - lake Meerfelder Maar KW - isotopic composition KW - oxygen isotope KW - climate KW - cellulose KW - radiocarbon KW - temperature KW - record KW - model Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459169 SN - 1866-8372 IS - 1135 ER - TY - GEN A1 - Mann, Michael E. A1 - Rahmstorf, Stefan A1 - Kornhuber, Kai A1 - Steinman, Byron A. A1 - Miller, Sonya K. A1 - Petri, Stefan A1 - Coumou, Dim T1 - Projected changes in persistent extreme summer weather events BT - the role of quasi-resonant amplification T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Persistent episodes of extreme weather in the Northern Hemisphere summer have been associated with high-amplitude quasi-stationary atmospheric Rossby waves, with zonal wave numbers 6 to 8 resulting from the phenomenon of quasi-resonant amplification (QRA). A fingerprint for the occurrence of QRA can be defined in terms of the zonally averaged surface temperature field. Examining state-of-the-art [Coupled Model Intercomparison Project Phase 5 (CMIP5)] climate model projections, we find that QRA events are likely to increase by similar to 50% this century under business-as-usual carbon emissions, but there is considerable variation among climate models. Some predict a near tripling of QRA events by the end of the century, while others predict a potential decrease. Models with amplified Arctic warming yield the most pronounced increase in QRA events. The projections are strongly dependent on assumptions regarding the nature of changes in radiative forcing associated with anthropogenic aerosols over the next century. One implication of our findings is that a reduction in midlatitude aerosol loading could actually lead to Arctic de-amplification this century, ameliorating potential increases in persistent extreme weather events. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 994 KW - planetary wave resonance KW - northern KW - atmosphere KW - attribution KW - circulation Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446416 SN - 1866-8372 IS - 994 ER - TY - GEN A1 - Mainka, Stefan A1 - Wissel, Jörg A1 - Völler, Heinz A1 - Evers, Stefan T1 - The use of rhythmic auditory stimulation to optimize treadmill training for stroke patients BT - a randomized controlled trial T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - The use of functional music in gait training termed rhythmic auditory stimulation (RAS) and treadmill training (TT) have both been shown to be effective in stroke patients (SP). The combination of RAS and treadmill training (RAS-TT) has not been clinically evaluated to date. The aim of the study was to evaluate the efficacy of RAS-TT on functional gait in SR The protocol followed the design of an explorative study with a rater-blinded three arm prospective randomized controlled parallel group design. Forty-five independently walking SP with a hemiparesis of the lower limb or an unsafe and asymmetrical walking pattern were recruited. RAS-TT was carried out over 4 weeks with TT and neurodevelopmental treatment based on Bobath approach (NDT) serving as control interventions. For RAS-TT functional music was adjusted individually while walking on the treadmill. Pre and post-assessments consisted of the fast gait speed test (FGS), a gait analysis with the locometre (LOC), 3 min walking time test (3MWT), and an instrumental evaluation of balance (IEB). Raters were blinded to group assignments. An analysis of covariance (ANCOVA) was performed with affiliated measures from pre-assessment and time between stroke and start of study as covariates. Thirty-five participants (mean age 63.6 +/- 8.6 years, mean time between stroke and start of study 42.1 +/- 23.7 days) completed the study (11 RAS-TT, 13 TT, 11 NDT). Significant group differences occurred in the FGS for adjusted post-measures in gait velocity [F-(2,F- (34)) = 3.864, p = 0.032; partial eta(2) = 0.205] and cadence [F-(2,F- 34) = 7.656, p = 0.002; partial eta(2) = 0.338]. Group contrasts showed significantly higher values for RAS-TT. Stride length results did not vary between the groups. LOC, 3MWT, and IEB did not indicate group differences. One patient was withdrawn from TT because of pain in one arm. The study provides first evidence for a higher efficacy of RAS-TT in comparison to the standard approaches TT and NDT in restoring functional gait in SP. The results support the implementation of functional music in neurological gait rehabilitation and its use in combination with treadmill training. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 655 KW - stroke rehabilitation KW - exercise movement techniques KW - music therapy KW - music KW - gait Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459179 SN - 1866-8364 IS - 655 ER - TY - GEN A1 - Kruse, Julia A1 - Kummer, Volker A1 - Shivas, Roger G. A1 - Thines, Marco T1 - The first smut fungus, Thecaphora anthemidis sp. nov. (Glomosporiaceae), described from Anthemis (Asteraceae) T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - There are 63 known species of Thecaphora (Glomosporiaceae, Ustilaginomycotina), a third of which occur on Asteraceae. These smut fungi produce yellowish-brown to reddish-brown masses of spore balls in specific, mostly regenerative, plant organs. A species of Thecaphora was collected in the flower heads of Anthemis chia (Anthemideae, Asteraceae) on Rhodes Island, Greece, in 2015 and 2017, which represents the first smut record of a smut fungus on a host plant species in this tribe. Based on its distinctive morphology, host species and genetic divergence, this species is described as Thecaphora anthemidis sp. nov. Molecular barcodes of the ITS region are provided for this and several other species of Thecaphora. A phylogenetic and morphological comparison to closely related species showed that Th. anthemidis differed from other species of Thecaphora. Thecaphora anthemidis produced loose spore balls in the flower heads and peduncles of Anthemis chia unlike other flower-infecting species. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 995 KW - Glomosporiaceae KW - host specificity KW - internal transcribed spacer KW - molecular phylogenetics KW - smut fungi Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446377 SN - 1866-8372 SP - 39 EP - 50 ER - TY - GEN A1 - Krasotkina, Anna A1 - Götz, Antonia A1 - Höhle, Barbara A1 - Schwarzer, Gudrun T1 - Perceptual narrowing in speech and face recognition BT - evidence for intra-individual cross-domain relations T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - During the first year of life, infants undergo perceptual narrowing in the domains of speech and face perception. This is typically characterized by improvements in infants' abilities in discriminating among stimuli of familiar types, such as native speech tones and same-race faces. Simultaneously, infants begin to decline in their ability to discriminate among stimuli of types with which they have little experience, such as nonnative tones and other-race faces. The similarity in time-frames during which perceptual narrowing seems to occur in the domains of speech and face perception has led some researchers to hypothesize that the perceptual narrowing in these domains could be driven by shared domain-general processes. To explore this hypothesis, we tested 53 Caucasian 9-month-old infants from monolingual German households on their ability to discriminate among non-native Cantonese speech tones, as well among same-race German faces and other-race Chinese faces. We tested the infants using an infant-controlled habituation-dishabituation paradigm, with infants' preferences for looking at novel stimuli versus the habituated stimuli (dishabituation scores) acting as indicators of discrimination ability. As expected for their age, infants were able to discriminate between same-race faces, but not between other-race faces or non-native speech tones. Most interestingly, we found that infants' dishabituation scores for the non-native speech tones and other-race faces showed significant positive correlations, while the dishabituation scores for non-native speech tones and same-race faces did not. These results therefore support the hypothesis that shared domain-general mechanisms may drive perceptual narrowing in the domains of speech and face perception. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 639 KW - perceptual narrowing KW - perceptual reorganization KW - other-race effect KW - face perception KW - speech perception KW - habituation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459180 SN - 1866-8364 IS - 639 ER - TY - GEN A1 - König, Johanna A1 - Block, Andrea A1 - Becker, Matthias A1 - Fenske, Kristin A1 - Hertel, Johannes A1 - Van der Auwera, Sandra A1 - Zymara, Kathleen A1 - Völzke, Henry A1 - Freyberger, Harald Jürgen A1 - Grabe, Hans Jörgen T1 - Assessment of subjective emotional valence and long-lasting impact of life events BT - development and psychometrics of the Stralsund Life Event List (SEL) T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Background: Life events (LEs) are associated with future physical and mental health. They are crucial for understanding the pathways to mental disorders as well as the interactions with biological parameters. However, deeper insight is needed into the complex interplay between the type of LE, its subjective evaluation and accompanying factors such as social support. The "Stralsund Life Event List" (SEL) was developed to facilitate this research. Methods: The SEL is a standardized interview that assesses the time of occurrence and frequency of 81 LEs, their subjective emotional valence, the perceived social support during the LE experience and the impact of past LEs on present life. Data from 2265 subjects from the general population-based cohort study "Study of Health in Pomerania" (SHIP) were analysed. Based on the mean emotional valence ratings of the whole sample, LEs were categorized as "positive" or "negative". For verification, the SEL was related to lifetime major depressive disorder (MDD; Munich Composite International Diagnostic Interview), childhood trauma (Childhood Trauma Questionnaire), resilience (Resilience Scale) and subjective health (SF-12 Health Survey). Results: The report of lifetime MDD was associated with more negative emotional valence ratings of negative LEs (OR = 2.96, p < 0.0001). Negative LEs (b = 0.071, p < 0.0001, beta = 0.25) and more negative emotional valence ratings of positive LEs (b = 3.74, p < 0.0001, beta = 0.11) were positively associated with childhood trauma. In contrast, more positive emotional valence ratings of positive LEs were associated with higher resilience (b = -7.05, p < 0.0001, beta = 0.13), and a lower present impact of past negative LEs was associated with better subjective health (b = 2.79, p = 0.001, beta = 0.05). The internal consistency of the generated scores varied considerably, but the mean value was acceptable (averaged Cronbach's alpha > 0.75). Conclusions: The SEL is a valid instrument that enables the analysis of the number and frequency of LEs, their emotional valence, perceived social support and current impact on life on a global score and on an individual item level. Thus, we can recommend its use in research settings that require the assessment and analysis of the relationship between the occurrence and subjective evaluation of LEs as well as the complex balance between distressing and stabilizing life experiences. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 704 KW - positive life events KW - negative life events KW - general population KW - emotional valence KW - depressive disorder Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459856 SN - 1866-8364 IS - 704 ER - TY - GEN A1 - Rizzo, Giovanna A1 - Laurita, Salvatore A1 - Altenberger, Uwe T1 - The Timpa delle Murge ophiolitic gabbros, southern Apennines BT - insights from petrology and geochemistry and consequences to the geodynamic setting T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The Timpa delle Murge ophiolite in the North Calabrian Unit is part of the Liguride Complex (southern Apennines). The study is concentrated on the gabbroic part of the ophiolite of the Pollino area. They preserve the high-grade ocean floor metamorphic and locally developed flaser textures under ocean floor conditions. The primary magmatic assemblages are clinopyroxene, plagioclase, and opaques. Brown hornblende is a late magmatic phase. Green hornblende, actinolite, albite, chlorite and epidote display metamorphic recrystallization under lower amphibolite facies conditions, followed by greenschist facies. The gabbros show subalkaline near to alkaline character with a tendency to a more calkalkaline trend. The normalization to primitive mantle and mid-ocean ridge basalt (N-MORB) compositions indicates a considerable depletion in Nb, P, Zr and Ti and an enrichment in Ba, Rb, K, Sr and Eu. This points to a mantle source, which is not compatible with a "normal" mid-ocean ridge situation. Rather, the gabbros are generated from a N-MORB-like melt with a strong crustal component, which was influenced by subduction related fluids and episodic melting during mid-ocean-ridge processes. Plausible geodynamic settings of the Timpa delle Murge gabbros are oceanic back-arc positions with embryonic MORB-activities. Similar slab contaminated magmatism is also known from the early stage of island arc formation in supra-subduction zone environments like the Izu-Bonin-Mariana island arc. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1002 KW - Southern Apennines KW - Liguride Complex KW - North Calabrian Unit KW - ophiolite KW - gabbros Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459928 SN - 1866-8372 IS - 1002 SP - 5 EP - 20 ER - TY - GEN A1 - Bridwell, David A. A1 - Cavanagh, James F. A1 - Collins, Anne G. E. A1 - Nunez, Michael D. A1 - Srinivasan, Ramesh A1 - Stober, Sebastian A1 - Calhoun, Vince D. T1 - Moving beyond ERP components BT - a selective review of approaches to integrate EEG and behavior T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Relationships between neuroimaging measures and behavior provide important clues about brain function and cognition in healthy and clinical populations. While electroencephalography (EEG) provides a portable, low cost measure of brain dynamics, it has been somewhat underrepresented in the emerging field of model-based inference. We seek to address this gap in this article by highlighting the utility of linking EEG and behavior, with an emphasis on approaches for EEG analysis that move beyond focusing on peaks or "components" derived from averaging EEG responses across trials and subjects (generating the event-related potential, ERP). First, we review methods for deriving features from EEG in order to enhance the signal within single-trials. These methods include filtering based on user-defined features (i.e., frequency decomposition, time-frequency decomposition), filtering based on data-driven properties (i.e., blind source separation, BSS), and generating more abstract representations of data (e.g., using deep learning). We then review cognitive models which extract latent variables from experimental tasks, including the drift diffusion model (DDM) and reinforcement learning (RL) approaches. Next, we discuss ways to access associations among these measures, including statistical models, data-driven joint models and cognitive joint modeling using hierarchical Bayesian models (HBMs). We think that these methodological tools are likely to contribute to theoretical advancements, and will help inform our understandings of brain dynamics that contribute to moment-to-moment cognitive function. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 656 KW - EEG KW - ERP KW - blind source separation KW - partial least squares KW - canonical correlations analysis KW - representational similarity analysis KW - deep learning KW - hierarchical Bayesian model Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459667 SN - 1866-8364 IS - 656 ER - TY - GEN A1 - Hodgkins, Suzanne B. A1 - Richardson, Curtis J. A1 - Dommain, René A1 - Wang, Hongjun A1 - Glaser, Paul H. A1 - Verbeke, Brittany A1 - Winkler, B. Rose A1 - Cobb, Alexander R. A1 - Rich, Virginia I. A1 - Missilmani, Malak A1 - Flanagan, Neal A1 - Ho, Mengchi A1 - Hoyt, Alison M. A1 - Harvey, Charles F. A1 - Vining, S. Rose A1 - Hough, Moira A. A1 - Moore, Tim R. A1 - Richard, Pierre J. H. A1 - De La Cruz, Florentino B. A1 - Toufaily, Joumana A1 - Hamdan, Rasha A1 - Cooper, William T. A1 - Chanton, Jeffrey P. T1 - Tropical peatland carbon storage linked to global latitudinal trends in peat recalcitrance T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Peatlands represent large terrestrial carbon banks. Given that most peat accumulates in boreal regions, where low temperatures and water saturation preserve organic matter, the existence of peat in (sub)tropical regions remains enigmatic. Here we examined peat and plant chemistry across a latitudinal transect from the Arctic to the tropics. Near-surface low-latitude peat has lower carbohydrate and greater aromatic content than near-surface high-latitude peat, creating a reduced oxidation state and resulting recalcitrance. This recalcitrance allows peat to persist in the (sub)tropics despite warm temperatures. Because we observed similar declines in carbohydrate content with depth in high-latitude peat, our data explain recent field-scale deep peat warming experiments in which catotelm (deeper) peat remained stable despite temperature increases up to 9 degrees C. We suggest that high-latitude deep peat reservoirs may be stabilized in the face of climate change by their ultimately lower carbohydrate and higher aromatic composition, similar to tropical peats. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1125 KW - dissolved organic matter KW - greenhouse gas fluxes KW - permafrost thaw KW - Northern Minnesota KW - FTIR spectroscopy KW - lignin content KW - brown rot KW - decomposition KW - chemistry KW - dynamics Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459658 SN - 1866-8372 IS - 1125 ER - TY - GEN A1 - Alonso, Sergio A1 - Stange, Maike A1 - Beta, Carsten T1 - Modeling random crawling, membrane deformation and intracellular polarity of motile amoeboid cells T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - Amoeboid movement is one of the most widespread forms of cell motility that plays a key role in numerous biological contexts. While many aspects of this process are well investigated, the large cell-to-cell variability in the motile characteristics of an otherwise uniform population remains an open question that was largely ignored by previous models. In this article, we present a mathematical model of amoeboid motility that combines noisy bistable kinetics with a dynamic phase field for the cell shape. To capture cell-to-cell variability, we introduce a single parameter for tuning the balance between polarity formation and intracellular noise. We compare numerical simulations of our model to experiments with the social amoeba Dictyostelium discoideum. Despite the simple structure of our model, we found close agreement with the experimental results for the center-of-mass motion as well as for the evolution of the cell shape and the overall intracellular patterns. We thus conjecture that the building blocks of our model capture essential features of amoeboid motility and may serve as a starting point for more detailed descriptions of cell motion in chemical gradients and confined environments. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1014 KW - signaling system KW - eukaryotic chemotaxis KW - Dictyostelium cells KW - actin cytoskeleton KW - excitable networks KW - PIP3 waves KW - migration KW - dynamics KW - oscillations KW - transduction Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459745 SN - 1866-8372 IS - 1014 ER - TY - GEN A1 - Krupkova, Olga A1 - Sadowska, Aleksandra A1 - Kameda, Takuya A1 - Hitzl, Wolfgang A1 - Hausmann, Oliver Nic A1 - Klasen, Jürgen A1 - Wuertz-Kozak, Karin T1 - p38 MaPK facilitates crosstalk between endoplasmic reticulum stress and IL-6 release in the intervertebral Disc T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Degenerative disc disease is associated with increased expression of pro-inflammatory cytokines in the intervertebral disc (IVD). However, it is not completely clear how inflammation arises in the IVD and which cellular compartments are involved in this process. Recently, the endoplasmic reticulum (ER) has emerged as a possible modulator of inflammation in age-related disorders. In addition, ER stress has been associated with the microenvironment of degenerated IVDs. Therefore, the aim of this study was to analyze the effects of ER stress on inflammatory responses in degenerated human IVDs and associated molecular mechanisms. Gene expression of ER stress marker GRP78 and pro-inflammatory cytokines IL-6, IL-8, IL-1 beta, and TNF-alpha was analyzed in human surgical IVD samples (n = 51, Pfirrmann grade 2-5). The expression of GRP78 positively correlated with the degeneration grade in lumbar IVDs and IL-6, but not with IL-1 beta and TNF-alpha. Another set of human surgical IVD samples (n = 25) was used to prepare primary cell cultures. ER stress inducer thapsigargin (Tg, 100 and 500 nM) activated gene and protein expression of IL-6 and induced phosphorylation of p38 MAPK. Both inhibition of p38 MAPK by SB203580 (10 mu M) and knockdown of ER stress effector CCAAT-enhancer-binding protein homologous protein (CHOP) reduced gene and protein expression of IL-6 in Tg-treated cells. Furthermore, the effects of an inflammatory microenvironment on ER stress were tested. TNF-alpha (5 and 10 ng/mL) did not activate ER stress, while IL-1 beta (5 and 10 ng/mL) activated gene and protein expression of GRP78, but did not influence [Ca2+](i) flux and expression of CHOP, indicating that pro-inflammatory cytokines alone may not induce ER stress in vivo. This study showed that IL-6 release in the IVD can be initiated following ER stress and that ER stress mediates IL-6 release through p38 MAPK and CHOP. Therapeutic targeting of ER stress response may reduce the consequences of the harsh microenvironment in degenerated IVD. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 705 KW - intervertebral disc KW - inflammation KW - endoplasmic reticulum stress KW - p38 MAPK KW - CHOP KW - GADD153 KW - GRP78 KW - IL-6 Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468698 SN - 1866-8364 IS - 705 ER - TY - GEN A1 - Siddiqui, Tarique Adnan A1 - Maute, Astrid A1 - Pedatella, Nick A1 - Yamazaki, Yosuke A1 - Lühr, Hermann A1 - Stolle, Claudia T1 - On the variability of the semidiurnal solar and lunar tides of the equatorial electrojet during sudden stratospheric warmings T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The variabilities of the semidiurnal solar and lunar tides of the equatorial electrojet (EEJ) are investigated during the 2003, 2006, 2009 and 2013 major sudden stratospheric warming (SSW) events in this study. For this purpose, ground-magnetometer recordings at the equatorial observatories in Huancayo and Fúquene are utilized. Results show a major enhancement in the amplitude of the EEJ semidiurnal lunar tide in each of the four warming events. The EEJ semidiurnal solar tidal amplitude shows an amplification prior to the onset of warmings, a reduction during the deceleration of the zonal mean zonal wind at 60∘ N and 10 hPa, and a second enhancement a few days after the peak reversal of the zonal mean zonal wind during all four SSWs. Results also reveal that the amplitude of the EEJ semidiurnal lunar tide becomes comparable or even greater than the amplitude of the EEJ semidiurnal solar tide during all these warming events. The present study also compares the EEJ semidiurnal solar and lunar tidal changes with the variability of the migrating semidiurnal solar (SW2) and lunar (M2) tides in neutral temperature and zonal wind obtained from numerical simulations at E-region heights. A better agreement between the enhancements of the EEJ semidiurnal lunar tide and the M2 tide is found in comparison with the enhancements of the EEJ semidiurnal solar tide and the SW2 tide in both the neutral temperature and zonal wind at the E-region altitudes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1075 KW - middle atmosphere KW - latitude ionosphere KW - temperature changes KW - lower thermosphere KW - magnetic field KW - TIME-GCM KW - winds KW - circulation KW - events KW - winter Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468389 SN - 1866-8372 IS - 1075 SP - 1545 EP - 1562 ER - TY - GEN A1 - Omori, Toshihiro A1 - Winter, Katja A1 - Shinohara, Kyosuke A1 - Hamada, Hiroshi A1 - Ishikawa, Takuji T1 - Simulation of the nodal flow of mutant embryos with a small number of cilia BT - comparison of mechanosensing and vesicle transport hypotheses T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - Left-right (L-R) asymmetry in the body plan is determined by nodal flow in vertebrate embryos. Shinohara et al. (Shinohara K et al. 2012 Nat. Commun. 3, 622 (doi:10.1038/ncomms1624)) used Dpcd and Rfx3 mutant mouse embryos and showed that only a few cilia were sufficient to achieve L-R asymmetry. However, the mechanism underlying the breaking of symmetry by such weak ciliary flow is unclear. Flow-mediated signals associated with the L-R asymmetric organogenesis have not been clarified, and two different hypotheses-vesicle transport and mechanosensing-are now debated in the research field of developmental biology. In this study, we developed a computational model of the node system reported by Shinohara et al. and examined the feasibilities of the two hypotheses with a small number of cilia. With the small number of rotating cilia, flow was induced locally and global strong flow was not observed in the node. Particles were then effectively transported only when they were close to the cilia, and particle transport was strongly dependent on the ciliary positions. Although the maximum wall shear rate was also influenced by ciliary position, the mean wall shear rate at the perinodal wall increased monotonically with the number of cilia. We also investigated the membrane tension of immotile cilia, which is relevant to the regulation of mechanotransduction. The results indicated that tension of about 0.1 mu Nm(-1) was exerted at the base even when the fluid shear rate was applied at about 0.1 s(-1). The area of high tension was also localized at the upstream side, and negative tension appeared at the downstream side. Such localization may be useful to sense the flow direction at the periphery, as time-averaged anticlockwise circulation was induced in the node by rotation of a few cilia. Our numerical results support the mechanosensing hypothesis, and we expect that our study will stimulate further experimental investigations of mechanotransduction in the near future. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1056 KW - nodal flow KW - left-right asymmetry KW - boundary element method KW - fluid-structure interaction Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468734 SN - 1866-8372 IS - 1056 ER - TY - GEN A1 - Beermann, Jan A1 - Westbury, Michael V. A1 - Hofreiter, Michael A1 - Hilgers, Leon A1 - Deister, Fabian A1 - Neumann, Hermann A1 - Raupach, Michael J. T1 - Cryptic species in a well-known habitat BT - applying taxonomics to the amphipod genus Epimeria (Crustacea, Peracarida) T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - Taxonomy plays a central role in biological sciences. It provides a communication system for scientists as it aims to enable correct identification of the studied organisms. As a consequence, species descriptions should seek to include as much available information as possible at species level to follow an integrative concept of 'taxonomics'. Here, we describe the cryptic species Epimeria frankei sp. nov. from the North Sea, and also redescribe its sister species, Epimeria cornigera. The morphological information obtained is substantiated by DNA barcodes and complete nuclear 18S rRNA gene sequences. In addition, we provide, for the first time, full mitochondrial genome data as part of a metazoan species description for a holotype, as well as the neotype. This study represents the first successful implementation of the recently proposed concept of taxonomics, using data from high-throughput technologies for integrative taxonomic studies, allowing the highest level of confidence for both biodiversity and ecological research. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1059 KW - multiple sequence alignment KW - Oxidase Subunit-I KW - mitochondrial genome KW - control region KW - Ribosomal-RNA KW - asellota crustacea KW - gammarus crustacea KW - deep-sea KW - DNA KW - evolution Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-460792 SN - 1866-8372 IS - 1059 ER - TY - GEN A1 - Kucian, Karin A1 - Zuber, Isabelle A1 - Kohn, Juliane A1 - Poltz, Nadine A1 - Wyschkon, Anne A1 - Esser, Günter A1 - von Aster, Michael G. T1 - Relation between mathematical performance, math anxiety, and affective priming in children with and without developmental dyscalculia T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Many children show negative emotions related to mathematics and some even develop mathematics anxiety. The present study focused on the relation between negative emotions and arithmetical performance in children with and without developmental dyscalculia (DD) using an affective priming task. Previous findings suggested that arithmetic performance is influenced if an affective prime precedes the presentation of an arithmetic problem. In children with DD specifically, responses to arithmetic operations are supposed to be facilitated by both negative and mathematics-related primes (= negative math priming effect). We investigated mathematical performance, math anxiety, and the domain-general abilities of 172 primary school children (76 with DD and 96 controls). All participants also underwent an affective priming task which consisted of the decision whether a simple arithmetic operation (addition or subtraction) that was preceded by a prime (positive/negative/neutral or mathematics-related) was true or false. Our findings did not reveal a negative math priming effect in children with DD. Furthermore, when considering accuracy levels, gender, or math anxiety, the negative math priming effect could not be replicated. However, children with DD showed more math anxiety when explicitly assessed by a specific math anxiety interview and showed lower mathematical performance compared to controls. Moreover, math anxiety was equally present in boys and girls, even in the earliest stages of schooling, and interfered negatively with performance. In conclusion, mathematics is often associated with negative emotions that can be manifested in specific math anxiety, particularly in children with DD. Importantly, present findings suggest that in the assessed age group, it is more reliable to judge math anxiety and investigate its effects on mathematical performance explicitly by adequate questionnaires than by an affective math priming task. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 684 KW - developmental dyscalculia KW - mathematics KW - affective priming KW - calculation KW - arithmetic KW - anxiety KW - gender KW - children Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-460671 SN - 1866-8364 IS - 684 ER - TY - GEN A1 - Totz, Sonja Juliana A1 - Löber, Jakob A1 - Totz, Jan Frederik A1 - Engel, Harald T1 - Control of transversal instabilities in reaction-diffusion systems T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - In two-dimensional reaction-diffusion systems, local curvature perturbations on traveling waves are typically damped out and vanish. However, if the inhibitor diffuses much faster than the activator, transversal instabilities can arise, leading from flat to folded, spatio-temporally modulated waves and to spreading spiral turbulence. Here, we propose a scheme to induce or inhibit these instabilities via a spatio-temporal feedback loop. In a piecewise-linear version of the FitzHugh-Nagumo model, transversal instabilities and spiral turbulence in the uncontrolled system are shown to be suppressed in the presence of control, thereby stabilizing plane wave propagation. Conversely, in numerical simulations with the modified Oregonator model for the photosensitive Belousov-Zhabotinsky reaction, which does not exhibit transversal instabilities on its own, we demonstrate the feasibility of inducing transversal instabilities and study the emerging wave patterns in a well-controlled manner. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 962 KW - traveling waves KW - control KW - transversal instabilities Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469762 SN - 1866-8372 IS - 962 ER - TY - GEN A1 - Mkaouer, Bessem A1 - Hammoudi-Nassib, Sarra A1 - Amara, Samiha A1 - Chaabène, Helmi T1 - Evaluating the physical and basic gymnastics skills assessment for talent identification in men’s artistic gymnastics proposed by the International Gymnastics Federation T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - This study aimed to determine the specific physical and basic gymnastics skills considered critical in gymnastics talent identification and selection as well as in promoting men’s artistic gymnastics performances. Fifty-one boys from a provincial gymnastics team (age 11.03 ± 0.95 years; height 1.33 ± 0.05 m; body mass 30.01 ± 5.53 kg; body mass index [BMI] 16.89 ± 3.93 kg/m²) regularly competing at national level voluntarily participated in this study. Anthropometric measures as well as the men’s artistic gymnastics physical test battery (i.e., International Gymnastics Federation [FIG] age group development programme) were used to assess the somatic and physical fitness profile of participants, respectively. The physical characteristics assessed were: muscle strength, flexibility, speed, endurance, and muscle power. Test outcomes were subjected to a principal components analysis to identify the most representative factors. The main findings revealed that power speed, isometric and explosive strength, strength endurance, and dynamic and static flexibility are the most determinant physical fitness aspects of the talent selection process in young male artistic gymnasts. These findings are of utmost importance for talent identification, selection, and development. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 691 KW - young male gymnast KW - fitness performance KW - assessment KW - selection KW - development Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-460049 SN - 1866-8364 IS - 691 SP - 383 EP - 392 ER - TY - GEN A1 - Lara, Mark J. A1 - Nitze, Ingmar A1 - Große, Guido A1 - McGuire, David T1 - Tundra landform and vegetation productivity trend maps for the Arctic Coastal Plain of northern Alaska T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Arctic tundra landscapes are composed of a complex mosaic of patterned ground features, varying in soil moisture, vegetation composition, and surface hydrology over small spatial scales (10-100 m). The importance of microtopography and associated geomorphic landforms in influencing ecosystem structure and function is well founded, however, spatial data products describing local to regional scale distribution of patterned ground or polygonal tundra geomorphology are largely unavailable. Thus, our understanding of local impacts on regional scale processes (e.g., carbon dynamics) may be limited. We produced two key spatiotemporal datasets spanning the Arctic Coastal Plain of northern Alaska (similar to 60,000 km(2)) to evaluate climate-geomorphological controls on arctic tundra productivity change, using (1) a novel 30m classification of polygonal tundra geomorphology and (2) decadal-trends in surface greenness using the Landsat archive (1999-2014). These datasets can be easily integrated and adapted in an array of local to regional applications such as (1) upscaling plot-level measurements (e.g., carbon/energy fluxes), (2) mapping of soils, vegetation, or permafrost, and/or (3) initializing ecosystem biogeochemistry, hydrology, and/or habitat modeling. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1035 KW - spatial-distribution KW - lake basins KW - microtopography KW - water KW - ice KW - accumulation KW - degradation KW - permafrost KW - dynamics KW - barrow Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459875 SN - 1866-8372 IS - 1035 ER - TY - GEN A1 - Krstic, Jelena A1 - Galhuber, Markus A1 - Schulz, Tim Julius A1 - Schupp, Michael A1 - Prokesch, Andreas T1 - p53 as a dichotomous regulator of liver disease BT - the dose makes the medicine T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Lifestyle-related disorders, such as the metabolic syndrome, have become a primary risk factor for the development of liver pathologies that can progress from hepatic steatosis, hepatic insulin resistance, steatohepatitis, fibrosis and cirrhosis, to the most severe condition of hepatocellular carcinoma (HCC). While the prevalence of liver pathologies is steadily increasing in modern societies, there are currently no approved drugs other than chemotherapeutic intervention in late stage HCC. Hence, there is a pressing need to identify and investigate causative molecular pathways that can yield new therapeutic avenues. The transcription factor p53 is well established as a tumor suppressor and has recently been described as a central metabolic player both in physiological and pathological settings. Given that liver is a dynamic tissue with direct exposition to ingested nutrients, hepatic p53, by integrating cellular stress response, metabolism and cell cycle regulation, has emerged as an important regulator of liver homeostasis and dysfunction. The underlying evidence is reviewed herein, with a focus on clinical data and animal studies that highlight a direct influence of p53 activity on different stages of liver diseases. Based on current literature showing that activation of p53 signaling can either attenuate or fuel liver disease, we herein discuss the hypothesis that, while hyper-activation or loss of function can cause disease, moderate induction of hepatic p53 within physiological margins could be beneficial in the prevention and treatment of liver pathologies. Hence, stimuli that lead to a moderate and temporary p53 activation could present new therapeutic approaches through several entry points in the cascade from hepatic steatosis to HCC. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 963 KW - p53 KW - liver disease KW - insulin resistance KW - non-alcoholic fatty liver disease KW - non-alcoholic steatohepatitis KW - hepatocellular carcinoma KW - liver regeneration KW - mouse models Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468127 SN - 1866-8372 IS - 963 ER - TY - GEN A1 - van der Kant, Anne A1 - Biro, Szilvia A1 - Levelt, Claartje A1 - Huijbregts, Stephan T1 - Negative affect is related to reduced differential neural responses to social and non-social stimuli in 5-to-8-month-old infants BT - a functional near-infrared spectroscopy-study T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Both social perception and temperament in young infants have been related to social functioning later in life. Previous functional Near-Infrared Spectroscopy (fNIRS) data (Lloyd-Fox et al., 2009) showed larger blood-oxygenation changes for social compared to non-social stimuli in the posterior temporal cortex of five-month-old infants. We sought to replicate and extend these findings by using fNIRS to study the neural basis of social perception in relation to infant temperament (Negative Affect) in 37 five-to-eight-month-old infants. Infants watched short videos displaying either hand and facial movements of female actors (social dynamic condition) or moving toys and machinery (non-social dynamic condition), while fNIRS data were collected over temporal brain regions. Negative Affect was measured using the Infant Behavior Questionnaire. Results showed significantly larger blood-oxygenation changes in the right posterior-temporal region in the social compared to the non-social condition. Furthermore, this differential activation was smaller in infants showing higher Negative Affect. Our results replicate those of Lloyd-Fox et al. and confirmed that five-to-eight-month-old infants show cortical specialization for social perception. Furthermore, the decreased cortical sensitivity to social stimuli in infants showing high Negative Affect may be an early biomarker for later difficulties in social interaction. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 643 KW - functional near-infrared spectroscopy KW - fNIRS KW - social perception KW - infants KW - temperament KW - negative affect Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468136 SN - 1866-8364 IS - 643 SP - 23 EP - 30 ER - TY - GEN A1 - Taffarello, Denise A1 - Srinivasan, Raghavan A1 - Samprogna Mohor, Guilherme A1 - Guimarães, João Luis Bittencourt A1 - Calijuri, Maria do Carmo A1 - Mendiondo, Eduardo Mario T1 - Modeling freshwater quality scenarios with ecosystem-basedadaptation in the headwaters of the Cantareira system, Brazil T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Although hydrologic models provide hypothesis testing of complex dynamics occurring at catchments, fresh-water quality modeling is still incipient at many subtropical headwaters. In Brazil, a few modeling studies assess freshwater nutrients, limiting policies on hydrologic ecosystem services. This paper aims to compare freshwater quality scenarios under different land-use and land-cover (LULC) change, one of them related to ecosystem-based adaptation (EbA), in Brazilian headwaters. Using the spatially semi-distributed Soil and Water Assessment Tool (SWAT) model, nitrate, total phosphorous (TP) and sediment were modeled in catchments ranging from 7.2 to 1037 km(2). These head-waters were eligible areas of the Brazilian payment for ecosystem services (PES) projects in the Cantareira water supply system, which had supplied water to 9 million people in the Sao Paulo metropolitan region (SPMR). We considered SWAT modeling of three LULC scenarios: (i) recent past scenario (S1), with historical LULC in 1990; (ii) current land-use scenario (S2), with LULC for the period 2010-2015 with field validation; and (iii) future land-use scenario with PES (S2 + EbA). This latter scenario proposed forest cover restoration through EbA following the river basin plan by 2035. These three LULC scenarios were tested with a selected record of rainfall and evapotranspiration observed in 2006-2014, with the occurrence of extreme droughts. To assess hydrologic services, we proposed the hydrologic service index (HSI), as a new composite metric comparing water pollution levels (WPL) for reference catchments, related to the grey water footprint (greyWF) and water yield. On the one hand, water quality simulations allowed for the regionalization of greyWF at spatial scales under LULC scenarios. According to the critical threshold, HSI identified areas as less or more sustainable catchments. On the other hand, conservation practices simulated through the S2 + EbA scenario envisaged not only additional and viable best management practices (BMP), but also preventive decision-making at the headwaters of water supply systems. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 935 KW - assessment tool swat KW - international trade KW - atlantic forest KW - soil KW - management KW - services KW - drought KW - trends KW - calibration KW - catchments Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459253 SN - 1866-8372 IS - 935 SP - 4699 EP - 4723 ER - TY - GEN A1 - Goodwin, Guillaume C. H. A1 - Mudd, Simon M. A1 - Clubb, Fiona J. T1 - Unsupervised detection of salt marsh platforms BT - a topographic method T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Salt marshes filter pollutants, protect coastlines against storm surges, and sequester carbon, yet are under threat from sea level rise and anthropogenic modification. The sustained existence of the salt marsh ecosystem depends on the topographic evolution of marsh platforms. Quantifying marsh platform topography is vital for improving the management of these valuable landscapes. The determination of platform boundaries currently relies on supervised classification methods requiring near-infrared data to detect vegetation, or demands labour-intensive field surveys and digitisation. We propose a novel, unsupervised method to reproducibly isolate salt marsh scarps and platforms from a digital elevation model (DEM), referred to as Topographic Identification of Platforms (TIP). Field observations and numerical models show that salt marshes mature into subhorizontal platforms delineated by subvertical scarps. Based on this premise, we identify scarps as lines of local maxima on a slope raster, then fill landmasses from the scarps upward, thus isolating mature marsh platforms. We test the TIP method using lidar-derived DEMs from six salt marshes in England with varying tidal ranges and geometries, for which topographic platforms were manually isolated from tidal flats. Agreement between manual and unsupervised classification exceeds 94% for DEM resolutions of 1 m, with all but one site maintaining an accuracy superior to 90% for resolutions up to 3 m. For resolutions of 1 m, platforms detected with the TIP method are comparable in surface area to digitised platforms and have similar elevation distributions. We also find that our method allows for the accurate detection of local block failures as small as 3 times the DEM resolution. Detailed inspection reveals that although tidal creeks were digitised as part of the marsh platform, unsupervised classification categorises them as part of the tidal flat, causing an increase in false negatives and overall platform perimeter. This suggests our method may benefit from combination with existing creek detection algorithms. Fallen blocks and high tidal flat portions, associated with potential pioneer zones, can also lead to differences between our method and supervised mapping. Although pioneer zones prove difficult to classify using a topographic method, we suggest that these transition areas should be considered when analysing erosion and accretion processes, particularly in the case of incipient marsh platforms. Ultimately, we have shown that unsupervised classification of marsh platforms from high-resolution topography is possible and sufficient to monitor and analyse topographic evolution. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 936 KW - accuracy assessment KW - tidal flats KW - vegetation KW - extraction KW - elevation KW - sedimentation KW - opportunity KW - ecosystems KW - morphology KW - salinity Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459329 SN - 1866-8372 IS - 936 SP - 239 EP - 255 ER - TY - GEN A1 - Schütz, Felina A1 - Winterleitner, Gerd A1 - Huenges, Ernst T1 - Geothermal exploration in a sedimentary basin BT - new continuous temperature data and physical rock properties from northern Oman T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The lateral and vertical temperature distribution in Oman is so far only poorly understood, particularly in the area between Muscat and the Batinah coast, which is the area of this study and which is composed of Cenozoic sediments developed as part of a foreland basin of the Makran Thrust Zone. Temperature logs (T-logs) were run and physical rock properties of the sediments were analyzed to understand the temperature distribution, thermal and hydraulic properties, and heat-transport processes within the sedimentary cover of northern Oman. An advective component is evident in the otherwise conduction-dominated geothermal play system, and is caused by both topography and density driven flow. Calculated temperature gradients (T-gradients) in two wells that represent conductive conditions are 18.7 and 19.5 degrees C km(-1), corresponding to about 70-90 degrees C at 2000-3000 m depth. This indicates a geothermal potential that can be used for energy intensive applications like cooling or water desalinization. Sedimentation in the foreland basin was initiated after the obduction of the Semail Ophiolite in the late Campanian, and reflects the complex history of alternating periods of transgressive and regressive sequences with erosion of the Oman Mountains. Thermal and hydraulic parameters were analyzed of the basin's heterogeneous clastic and carbonate sedimentary sequence. Surface heat-flow values of 46.4 and 47.9 mW m(-2) were calculated from the T-logs and calculated thermal conductivity values in two wells. The results of this study serve as a starting point for assessing different geothermal applications that may be suitable for northern Oman. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 934 KW - continuous temperature logging KW - physical rock properties KW - sedimentary basin KW - geothermal applications in Oman Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459317 SN - 1866-8372 IS - 934 ER - TY - GEN A1 - Giulbudagian, Michael A1 - Yealland, Guy A1 - Hönzke, Stefan A1 - Edlich, Alexander A1 - Geisendörfer, Birte A1 - Kleuser, Burkhard A1 - Hedtrich, Sarah A1 - Calderón, Marcelo T1 - Breaking the barrier BT - potent anti-inflammatory activity following efficient topical delivery of etanercept using thermoresponsive nanogels T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Topical administration permits targeted, sustained delivery of therapeutics to human skin. Delivery to the skin, however, is typically limited to lipophilic molecules with molecular weight of < 500 Da, capable of crossing the stratum corneum. Nevertheless, there are indications protein delivery may be possible in barrier deficient skin, a condition found in several inflammatory skin diseases such as psoriasis, using novel nanocarrier systems. Methods: Water in water thermo-nanoprecipitation; dynamic light scattering; zeta potential measurement; nanoparticle tracking analysis; atomic force microscopy; cryogenic transmission electron microscopy; UV absorption; centrifugal separation membranes; bicinchoninic acid assay; circular dichroism; TNF alpha binding ELISA; inflammatory skin equivalent construction; human skin biopsies; immunohistochemistry; fluorescence microscopy; western blot; monocyte derived Langerhans cells; ELISA Results: Here, we report the novel synthesis of thermoresponsive nanogels (tNG) and the stable encapsulation of the anti-TNFa fusion protein etanercept (ETR) (similar to 150 kDa) without alteration to its structure, as well as temperature triggered release from the tNGs. Novel tNG synthesis without the use of organic solvents was conducted, permitting in situ encapsulation of protein during assembly, something that holds great promise for easy manufacture and storage. Topical application of ETR loaded tNGs to inflammatory skin equivalents or tape striped human skin resulted in efficient ETR delivery throughout the SC and into the viable epidermis that correlated with clear anti-inflammatory effects. Notably, effective ETR delivery depended on temperature triggered release following topical application. Conclusion: Together these results indicate tNGs hold promise as a biocompatible and easy to manufacture vehicle for stable protein encapsulation and topical delivery into barrier-deficient skin. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1030 KW - thermoresponsive-nanogel KW - topical KW - anti-inflammatory therapy KW - etanercept KW - skin equivalents Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-459301 SN - 1866-8372 IS - 1030 SP - 450 EP - 463 ER - TY - GEN A1 - Krstic, Jelena A1 - Reinisch, Isabel A1 - Schupp, Michael A1 - Schulz, Tim Julius A1 - Prokesch, Andreas T1 - p53 functions in adipose tissue metabolism and homeostasis T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - As a tumor suppressor and the most frequently mutated gene in cancer, p53 is among the best-described molecules in medical research. As cancer is in most cases an age-related disease, it seems paradoxical that p53 is so strongly conserved from early multicellular organisms to humans. A function not directly related to tumor suppression, such as the regulation of metabolism in nontransformed cells, could explain this selective pressure. While this role of p53 in cellular metabolism is gradually emerging, it is imperative to dissect the tissue-and cell-specific actions of p53 and its downstream signaling pathways. In this review, we focus on studies reporting p53's impact on adipocyte development, function, and maintenance, as well as the causes and consequences of altered p53 levels in white and brown adipose tissue (AT) with respect to systemic energy homeostasis. While whole body p53 knockout mice gain less weight and fat mass under a high-fat diet owing to increased energy expenditure, modifying p53 expression specifically in adipocytes yields more refined insights: (1) p53 is a negative regulator of in vitro adipogenesis; (2) p53 levels in white AT are increased in diet-induced and genetic obesity mouse models and in obese humans; (3) functionally, elevated p53 in white AT increases senescence and chronic inflammation, aggravating systemic insulin resistance; (4) p53 is not required for normal development of brown AT; and (5) when p53 is activated in brown AT in mice fed a high-fat diet, it increases brown AT temperature and brown AT marker gene expression, thereby contributing to reduced fat mass accumulation. In addition, p53 is increasingly being recognized as crucial player in nutrient sensing pathways. Hence, despite existence of contradictory findings and a varying density of evidence, several functions of p53 in adipocytes and ATs have been emerging, positioning p53 as an essential regulatory hub in ATs. Future studies need to make use of more sophisticated in vivo model systems and should identify an AT-specific set of p53 target genes and downstream pathways upon different (nutrient) challenges to identify novel therapeutic targets to curb metabolic diseases. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1047 KW - p53 KW - adipose tissue KW - metabolic syndrome KW - obesity KW - adipogenesis KW - insulin resistance Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469069 SN - 1866-8372 IS - 1047 ER - TY - GEN A1 - Randall, Matthew J. A1 - Jüngel, Astrid A1 - Rimann, Markus A1 - Wuertz-Kozak, Karin T1 - Advances in the biofabrication of 3D skin in vitro BT - healthy and pathological models T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - The relevance for in vitro three-dimensional (3D) tissue culture of skin has been present for almost a century. From using skin biopsies in organ culture, to vascularized organotypic full-thickness reconstructed human skin equivalents, in vitro tissue regeneration of 3D skin has reached a golden era. However, the reconstruction of 3D skin still has room to grow and develop. The need for reproducible methodology, physiological structures and tissue architecture, and perfusable vasculature are only recently becoming a reality, though the addition of more complex structures such as glands and tactile corpuscles require advanced technologies. In this review, we will discuss the current methodology for biofabrication of 3D skin models and highlight the advantages and disadvantages of the existing systems as well as emphasize how new techniques can aid in the production of a truly physiologically relevant skin construct for preclinical innovation. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 680 KW - 3D tissue model KW - skin KW - in vitro KW - bioprinting KW - electrospinning KW - skin disease KW - biofabrication KW - preclinical testing Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468844 SN - 1866-8364 IS - 680 ER - TY - GEN A1 - Sadowska, Aleksandra A1 - Kameda, Takuya A1 - Krupkova, Olga A1 - Würtz-Kozak, Karin T1 - Osmosensing, osmosignalling and inflammation BT - how intervertebral disc cells respond to altered osmolarity T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Intervertebral disc (IVD) cells are naturally exposed to high osmolarity and complex mechanical loading, which drive microenvironmental osmotic changes. Age- and degeneration-induced degradation of the IVD's extracellular matrix causes osmotic imbalance, which, together with an altered function of cellular receptors and signalling pathways, instigates local osmotic stress. Cellular responses to osmotic stress include osmoadaptation and activation of pro-inflammatory pathways. This review summarises the current knowledge on how IVD cells sense local osmotic changes and translate these signals into physiological or pathophysiological responses, with a focus on inflammation. Furthermore, it discusses the expression and function of putative membrane osmosensors (e.g. solute carrier transporters, transient receptor potential channels, aquaporins and acid-sensing ion channels) and osmosignalling mediators [e.g. tonicity responseelement-binding protein/nuclear factor of activated T-cells 5 (TonEBP/NFAT5), nuclear factor kappa-lightchain-enhancer of activated B cells (NF-kappa B)] in healthy and degenerated IVDs. Finally, an overview of the potential therapeutic targets for modifying osmosensing and osmosignalling in degenerated IVDs is provided. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 693 KW - intervertebral disc degeneration KW - degenerative disc disease KW - osmolarity KW - hyper-osmolarity KW - hypo-osmolarity KW - osmotic KW - inflammatory KW - transient receptor potential channel KW - aquaporin KW - tonicity-responsive enhancer binding protein Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469080 SN - 1866-8364 IS - 693 ER - TY - GEN A1 - Möser, Christin A1 - Lorenz, Jessica S. A1 - Sajfutdinow, Martin A1 - Smith, David M. T1 - Pinpointed stimulation of EphA2 receptors via DNA-templated oligovalence T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - DNA nanostructures enable the attachment of functional molecules to nearly any unique location on their underlying structure. Due to their single-base-pair structural resolution, several ligands can be spatially arranged and closely controlled according to the geometry of their desired target, resulting in optimized binding and/or signaling interactions. Here, the efficacy of SWL, an ephrin-mimicking peptide that binds specifically to EphrinA2 (EphA2) receptors, increased by presenting up to three of these peptides on small DNA nanostructures in an oligovalent manner. Ephrin signaling pathways play crucial roles in tumor development and progression. Moreover, Eph receptors are potential targets in cancer diagnosis and treatment. Here, the quantitative impact of SWL valency on binding, phosphorylation (key player for activation) and phenotype regulation in EphA2-expressing prostate cancer cells was demonstrated. EphA2 phosphorylation was significantly increased by DNA trimers carrying three SWL peptides compared to monovalent SWL. In comparison to one of EphA2’s natural ligands ephrin-A1, which is known to bind promiscuously to multiple receptors, pinpointed targeting of EphA2 by oligovalent DNA-SWL constructs showed enhanced cell retraction. Overall, we show that DNA scaffolds can increase the potency of weak signaling peptides through oligovalent presentation and serve as potential tools for examination of complex signaling pathways. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1041 KW - DNA nanostructure KW - ephrin KW - EphA2 KW - SWL KW - PC-3 cells KW - multivalence Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-468828 SN - 1866-8372 IS - 1041 ER - TY - GEN A1 - Maares, Maria A1 - Keil, Claudia A1 - Koza, Jenny A1 - Straubing, Sophia A1 - Schwerdtle, Tanja A1 - Haase, Hajo T1 - In Vitro Studies on Zinc Binding and Buffering by Intestinal Mucins T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The investigation of luminal factors influencing zinc availability and accessibility in the intestine is of great interest when analyzing parameters regulating intestinal zinc resorption. Of note, intestinal mucins were suggested to play a beneficial role in the luminal availability of zinc. Their exact zinc binding properties, however, remain unknown and the impact of these glycoproteins on human intestinal zinc resorption has not been investigated in detail. Thus, the aim of this study is to elucidate the impact of intestinal mucins on luminal uptake of zinc into enterocytes and its transfer into the blood. In the present study, in vitro zinc binding properties of mucins were analyzed using commercially available porcine mucins and secreted mucins of the goblet cell line HT-29-MTX. The molecular zinc binding capacity and average zinc binding affinity of these glycoproteins demonstrates that mucins contain multiple zinc-binding sites with biologically relevant affinity within one mucin molecule. Zinc uptake into the enterocyte cell line Caco-2 was impaired by zinc-depleted mucins. Yet this does not represent their form in the intestinal lumen in vivo under zinc adequate conditions. In fact, zinc-uptake studies into enterocytes in the presence of mucins with differing degree of zinc saturation revealed zinc buffering by these glycoproteins, indicating that mucin-bound zinc is still available for the cells. Finally, the impact of mucins on zinc resorption using three-dimensional cultures was studied comparing the zinc transfer of a Caco-2/HT-29-MTX co-culture and conventional Caco-2 monoculture. Here, the mucin secreting co-cultures yielded higher fractional zinc resorption and elevated zinc transport rates, suggesting that intestinal mucins facilitate the zinc uptake into enterocytes and act as a zinc delivery system for the intestinal epithelium. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1079 KW - intestinal zinc resorption KW - zinc binding KW - mucus layer KW - intestinal mucins KW - in vitro intestinal model KW - goblet cells KW - Caco-2/HT-29-MTX-model Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469078 SN - 1866-8372 IS - 1079 ER - TY - GEN A1 - Sauermann, Antje A1 - Höhle, Barbara T1 - Word order in German child language and child-directed speech BT - A corpus analysis on the ordering of double objects in the German middlefield T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - We report two corpus analyses to examine the impact of animacy, definiteness, givenness and type of referring expression on the ordering of double objects in the spontaneous speech of German-speaking two- to four-year-old children and the child-directed speech of their mothers. The first corpus analysis revealed that definiteness, givenness and type of referring expression influenced word order variation in child language and child-directed speech when the type of referring expression distinguished between pronouns and lexical noun phrases. These results correspond to previous child language studies in English (e.g., de Marneffe et al. 2012). Extending the scope of previous studies, our second corpus analysis examined the role of different pronoun types on word order. It revealed that word order in child language and child-directed speech was predictable from the types of pronouns used. Different types of pronouns were associated with different sentence positions but also showed a strong correlation to givenness and definiteness. Yet, the distinction between pronoun types diminished the effects of givenness so that givenness had an independent impact on word order only in child-directed speech but not in child language. Our results support a multi-factorial approach to word order in German. Moreover, they underline the strong impact of the type of referring expression on word order and suggest that it plays a crucial role in the acquisition of the factors influencing word order variation. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 687 KW - German KW - word order KW - corpus study KW - language acquisition KW - information structure KW - referring expression Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-470174 SN - 1866-8364 IS - 687 ER - TY - GEN A1 - Kleuser, Burkhard T1 - Divergent role of sphingosine 1-phosphate in liver health and disease T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Two decades ago, sphingosine 1-phosphate (S1P) was discovered as a novel bioactive molecule that regulates a variety of cellular functions. The plethora of S1P-mediated effects is due to the fact that the sphingolipid not only modulates intracellular functions but also acts as a ligand of G protein-coupled receptors after secretion into the extracellular environment. In the plasma, S1P is found in high concentrations, modulating immune cell trafficking and vascular endothelial integrity. The liver is engaged in modulating the plasma S1P content, as it produces apolipoprotein M, which is a chaperone for the S1P transport. Moreover, the liver plays a substantial role in glucose and lipid homeostasis. A dysfunction of glucose and lipid metabolism is connected with the development of liver diseases such as hepatic insulin resistance, non-alcoholic fatty liver disease, or liver fibrosis. Recent studies indicate that S1P is involved in liver pathophysiology and contributes to the development of liver diseases. In this review, the current state of knowledge about S1P and its signaling in the liver is summarized with a specific focus on the dysregulation of S1P signaling in obesity-mediated liver diseases. Thus, the modulation of S1P signaling can be considered as a potential therapeutic target for the treatment of hepatic diseases. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1051 KW - sphingolipids KW - sphingosine kinase KW - fibrosis KW - non-alcoholic fatty liver disease KW - insulinresistance KW - liver fibrosis Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-474398 SN - 1866-8372 IS - 1051 ER - TY - GEN A1 - Lukan, Tjaša A1 - Machens, Fabian A1 - Coll, Anna A1 - Baebler, Špela A1 - Messerschmidt, Katrin A1 - Gruden, Kristina T1 - Plant X-tender BT - an extension of the AssemblX system for the assembly and expression of multigene constructs in plants T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Cloning multiple DNA fragments for delivery of several genes of interest into the plant genome is one of the main technological challenges in plant synthetic biology. Despite several modular assembly methods developed in recent years, the plant biotechnology community has not widely adopted them yet, probably due to the lack of appropriate vectors and software tools. Here we present Plant X-tender, an extension of the highly efficient, scarfree and sequence-independent multigene assembly strategy AssemblX,based on overlapdepended cloning methods and rare-cutting restriction enzymes. Plant X-tender consists of a set of plant expression vectors and the protocols for most efficient cloning into the novel vector set needed for plant expression and thus introduces advantages of AssemblX into plant synthetic biology. The novel vector set covers different backbones and selection markers to allow full design flexibility. We have included ccdB counterselection, thereby allowing the transfer of multigene constructs into the novel vector set in a straightforward and highly efficient way. Vectors are available as empty backbones and are fully flexible regarding the orientation of expression cassettes and addition of linkers between them, if required. We optimised the assembly and subcloning protocol by testing different scar-less assembly approaches: the noncommercial SLiCE and TAR methods and the commercial Gibson assembly and NEBuilder HiFi DNA assembly kits. Plant X-tender was applicable even in combination with low efficient homemade chemically competent or electrocompetent Escherichia coli. We have further validated the developed procedure for plant protein expression by cloning two cassettes into the newly developed vectors and subsequently transferred them to Nicotiana benthamiana in a transient expression setup. Thereby we show that multigene constructs can be delivered into plant cells in a streamlined and highly efficient way. Our results will support faster introduction of synthetic biology into plant science. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 990 KW - ligation cloning extract KW - DNA cloning KW - synthetic biology KW - multiple genes KW - vector system KW - transformation KW - recombination KW - protein KW - RNA KW - Methylation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446281 SN - 1866-8372 IS - 990 ER - TY - GEN A1 - Schaal, Frederik A1 - Rutloh, Michael A1 - Weidenfeld, Susanne A1 - Stumpe, Joachim A1 - Michler, Peter A1 - Pruss, Christof A1 - Osten, Wolfgang T1 - Optically addressed modulator for tunable spatial polarization control T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - We present an optically addressed non-pixelated spatial light modulator. The system is based on reversible photoalignment of a LC cell using a red light sensitive novel azobenzene photoalignment layer. It is an electrode-free device that manipulates the liquid crystal orientation and consequently the polarization via light without artifacts caused by electrodes. The capability to miniaturize the spatial light modulator allows the integration into a microscope objective. This includes a miniaturized 200 channel optical addressing system based on a VCSEL array and hybrid refractive-diffractive beam shapers. As an application example, the utilization as a microscope objective integrated analog phase contrast modulator is shown. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1001 KW - nematic liquid crystals KW - command surfaces KW - light modulator KW - alignment KW - films KW - polymer Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446263 SN - 1866-8372 IS - 1001 SP - 28119 EP - 28130 ER - TY - GEN A1 - Laepple, Thomas A1 - Münch, Thomas A1 - Casado, Mathieu A1 - Hoerhold, Maria A1 - Landais, Amaelle A1 - Kipfstuhl, Sepp T1 - On the similarity and apparent cycles of isotopic variations in East Antarctic snow pits T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Stable isotope ratios delta O-18 and delta D in polar ice provide a wealth of information about past climate evolution. Snow-pit studies allow us to relate observed weather and climate conditions to the measured isotope variations in the snow. They therefore offer the possibility to test our understanding of how isotope signals are formed and stored in firn and ice. As delta O-18 and delta D in the snowfall are strongly correlated to air temperature, isotopes in the near-surface snow are thought to record the seasonal cycle at a given site. Accordingly, the number of seasonal cycles observed over a given depth should depend on the accumulation rate of snow. However, snow-pit studies from different accumulation conditions in East Antarctica reported similar isotopic variability and comparable apparent cycles in the delta O-18 and delta D profiles with typical wavelengths of similar to 20 cm. These observations are unexpected as the accumulation rates strongly differ between the sites, ranging from 20 to 80mmw.e.yr(-1) (similar to 6-21 cm of snow per year). Various mechanisms have been proposed to explain the isotopic variations individually at each site; however, none of these are consistent with the similarity of the different profiles independent of the local accumulation conditions. Here, we systematically analyse the properties and origins of delta O-18 and delta D variations in high-resolution firn profiles from eight East Antarctic sites. First, we confirm the suggested cycle length (mean distance between peaks) of similar to 20 cm by counting the isotopic maxima. Spectral analysis further shows a strong similarity between the sites but indicates no dominant periodic features. Furthermore, the appar-ent cycle length increases with depth for most East Antarctic sites, which is inconsistent with burial and compression of a regular seasonal cycle. We show that these results can be explained by isotopic diffusion acting on a noise-dominated isotope signal. The firn diffusion length is rather stable across the Antarctic Plateau and thus leads to similar power spectral densities of the isotopic variations. This in turn implies a similar distance between isotopic maxima in the firn profiles. Our results explain a large set of observations discussed in the literature, providing a simple explanation for the interpretation of apparent cycles in shallow isotope records, without invoking complex mechanisms. Finally, the results underline previous suggestions that isotope signals in single ice cores from low-accumulation regions have a small signal-to-noise ratio and thus likely do not allow the reconstruction of interannual to decadal climate variations. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 932 KW - Dronning-Maud-Land KW - ice-core KW - climate variability KW - surface snow KW - stable-isotopes KW - water-isotopes KW - oxygen-isotope KW - south-pole KW - athmospheric circulation KW - mathematical-analysis Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446052 SN - 1866-8372 IS - 932 SP - 169 EP - 187 ER - TY - GEN A1 - Tabben, Montassar A1 - Ihsan, Mohammed A1 - Ghoul, Nihel A1 - Coquart, Jeremy A1 - Chaouachi, Anis A1 - Chaabene, Helmi A1 - Tourny, Claire A1 - Chamari, Karim T1 - Cold Water Immersion Enhanced Athletes’ Wellness and 10-m Short Sprint Performance 24-h After a Simulated Mixed Martial Arts Combat T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Objective: The aim of the present study was to examine the effect of Cold Water Immersion (CWI) on the recovery of physical performance, hematological stress markers and perceived wellness (i.e., Hooper scores) following a simulated Mixed Martial Arts (MMA) competition. Methods: Participants completed two experimental sessions in a counter-balanced order (CWI or passive recovery for control condition: CON), after a simulated MMAs competition (3 x 5-min MMA rounds separated by 1-min of passive rest). During CWI, athletes were required to submerge their bodies, except the trunk, neck and head, in the seated position in a temperature-controlled bath (similar to 10 degrees C) for 15-min. During CON, athletes were required to be in a seated position for 15-min in same room ambient temperature. Venous blood samples (creatine kinase, cortisol, and testosterone concentrations) were collected at rest (PRE-EX, i.e., before MMAs), immediately following MMAs (POST-EX), immediately following recovery (POST-R) and 24 h post MMAs (POST-24), whilst physical fitness (squat jump, countermovement-jump and 5- and 10-m sprints) and perceptual measures (well-being Hooper index: fatigue, stress, delayed onset muscle soreness (DOMS), and sleep) were collected at PRE-EX, POST-R and POST-24, and at PRE-EX and POST-24, respectively. Results: The main results indicate that POST-R sprint (5- and 10-m) performances were 'likely to very likely' (d = 0.64 and 0.65) impaired by prior CWI. However, moderate improvements were in 10-m sprint performance were 'likely' evident at POST-24 after CWI compared with CON (d = 0.53). Additionally, the use of CWI 'almost certainly' resulted in a large overall improvement in Hooper scores (d = 1.93). Specifically, CWI 'almost certainly' resulted in improved sleep quality (d = 1.36), stress (d = 1.56) and perceived fatigue (d = 1.51), and 'likely' resulted in a moderate decrease in DOMS (d = 0.60). Conclusion: The use of CWI resulted in an enhanced recovery of 10-m sprint performance, as well as improved perceived wellness 24-h following simulated MMA competition. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 707 KW - recovery KW - combat sports KW - MMA KW - delayed onset muscle soreness KW - stress KW - fatigue Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-446068 SN - 1866-8364 IS - 707 ER - TY - GEN A1 - Raatz, Michael A1 - van Velzen, Ellen A1 - Gaedke, Ursula T1 - Co‐adaptation impacts the robustness of predator–prey dynamics against perturbations T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Global change threatens the maintenance of ecosystem functions that are shaped by the persistence and dynamics of populations. It has been shown that the persistence of species increases if they possess larger trait adaptability. Here, we investigate whether trait adaptability also affects the robustness of population dynamics of interacting species and thereby shapes the reliability of ecosystem functions that are driven by these dynamics. We model co‐adaptation in a predator–prey system as changes to predator offense and prey defense due to evolution or phenotypic plasticity. We investigate how trait adaptation affects the robustness of population dynamics against press perturbations to environmental parameters and against pulse perturbations targeting species abundances and their trait values. Robustness of population dynamics is characterized by resilience, elasticity, and resistance. In addition to employing established measures for resilience and elasticity against pulse perturbations (extinction probability and return time), we propose the warping distance as a new measure for resistance against press perturbations, which compares the shapes and amplitudes of pre‐ and post‐perturbation population dynamics. As expected, we find that the robustness of population dynamics depends on the speed of adaptation, but in nontrivial ways. Elasticity increases with speed of adaptation as the system returns more rapidly to the pre‐perturbation state. Resilience, in turn, is enhanced by intermediate speeds of adaptation, as here trait adaptation dampens biomass oscillations. The resistance of population dynamics strongly depends on the target of the press perturbation, preventing a simple relationship with the adaptation speed. In general, we find that low robustness often coincides with high amplitudes of population dynamics. Hence, amplitudes may indicate the robustness against perturbations also in other natural systems with similar dynamics. Our findings show that besides counteracting extinctions, trait adaptation indeed strongly affects the robustness of population dynamics against press and pulse perturbations. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 809 KW - disturbance KW - evolutionary rescue KW - population dynamics KW - stability KW - trait adaptation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-442489 SN - 1866-8372 IS - 809 ER - TY - GEN A1 - Marelja, Zvonimir A1 - Leimkühler, Silke A1 - Missirlis, Fanis T1 - Iron sulfur and molybdenum cofactor enzymes regulate the Drosophila life cycle by controlling cell metabolism T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Iron sulfur (Fe-S) clusters and the molybdenum cofactor (Moco) are present at enzyme sites, where the active metal facilitates electron transfer. Such enzyme systems are soluble in the mitochondrial matrix, cytosol and nucleus, or embedded in the inner mitochondrial membrane, but virtually absent from the cell secretory pathway. They are of ancient evolutionary origin supporting respiration, DNA replication, transcription, translation, the biosynthesis of steroids, heme, catabolism of purines, hydroxylation of xenobiotics, and cellular sulfur metabolism. Here, Fe-S cluster and Moco biosynthesis in Drosophila melanogaster is reviewed and the multiple biochemical and physiological functions of known Fe-S and Moco enzymes are described. We show that RNA interference of Mocs3 disrupts Moco biosynthesis and the circadian clock. Fe-S-dependent mitochondrial respiration is discussed in the context of germ line and somatic development, stem cell differentiation and aging. The subcellular compartmentalization of the Fe-S and Moco assembly machinery components and their connections to iron sensing mechanisms and intermediary metabolism are emphasized. A biochemically active Fe-S core complex of heterologously expressed fly Nfs1, Isd11, IscU, and human frataxin is presented. Based on the recent demonstration that copper displaces the Fe-S cluster of yeast and human ferredoxin, an explanation for why high dietary copper leads to cytoplasmic iron deficiency in flies is proposed. Another proposal that exosomes contribute to the transport of xanthine dehydrogenase from peripheral tissues to the eye pigment cells is put forward, where the Vps16a subunit of the HOPS complex may have a specialized role in concentrating this enzyme within pigment granules. Finally, we formulate a hypothesis that (i) mitochondrial superoxide mobilizes iron from the Fe-S clusters in aconitase and succinate dehydrogenase; (ii) increased iron transiently displaces manganese on superoxide dismutase, which may function as a mitochondrial iron sensor since it is inactivated by iron; (iii) with the Krebs cycle thus disrupted, citrate is exported to the cytosol for fatty acid synthesis, while succinyl-CoA and the iron are used for heme biosynthesis; (iv) as iron is used for heme biosynthesis its concentration in the matrix drops allowing for manganese to reactivate superoxide dismutase and Fe-S cluster biosynthesis to reestablish the Krebs cycle. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 925 KW - aldehyde oxidase KW - DNA polymerase KW - electron transport chain KW - ecdysone KW - iron regulatory protein KW - quiescent mitochondria KW - magnetoreceptor KW - mitoflashes Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-445670 SN - 1866-8372 IS - 925 ER - TY - GEN A1 - Zwieback, Simon A1 - Kokelj, Steven V. A1 - Günther, Frank A1 - Boike, Julia A1 - Grosse, Guido A1 - Hajnsek, Irena T1 - Sub-seasonal thaw slump mass wasting is not consistently energy limited at the landscape scale T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Predicting future thaw slump activity requires a sound understanding of the atmospheric drivers and geomorphic controls on mass wasting across a range of timescales. On sub-seasonal timescales, sparse measurements indicate that mass wasting at active slumps is often limited by the energy available for melting ground ice, but other factors such as rainfall or the formation of an insulating veneer may also be relevant. To study the sub-seasonal drivers, we derive topographic changes from single-pass radar interferometric data acquired by the TanDEM-X satellites. The estimated elevation changes at 12m resolution complement the commonly observed planimetric retreat rates by providing information on volume losses. Their high vertical precision (around 30 cm), frequent observations (11 days) and large coverage (5000 km(2)) allow us to track mass wasting as drivers such as the available energy change during the summer of 2015 in two study regions. We find that thaw slumps in the Tuktoyaktuk coastlands, Canada, are not energy limited in June, as they undergo limited mass wasting (height loss of around 0 cm day 1) despite the ample available energy, suggesting the widespread presence of early season insulating snow or debris veneer. Later in summer, height losses generally increase (around 3 cm day 1), but they do so in distinct ways. For many slumps, mass wasting tracks the available energy, a temporal pattern that is also observed at coastal yedoma cliffs on the Bykovsky Peninsula, Russia. However, the other two common temporal trajectories are asynchronous with the available energy, as they track strong precipitation events or show a sudden speed-up in late August respectively. The observed temporal patterns are poorly related to slump characteristics like the headwall height. The contrasting temporal behaviour of nearby thaw slumps highlights the importance of complex local and temporally varying controls on mass wasting. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 926 KW - ground-ice KW - Tandem-X KW - Northeast Siberia KW - thermal regime KW - Peel Plateau KW - permafrost KW - erosion KW - Island KW - delta KW - yedoma Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-445688 SN - 1866-8372 IS - 926 SP - 549 EP - 564 ER - TY - GEN A1 - Eckstein, Lars T1 - Recollecting bones BT - the remains of German-Australian colonial entanglements T2 - Postcolonial Studies N2 - This article critically engages with the different politics of memory involved in debates over the restitution of Indigenous Australian ancestral remains stolen by colonial actors in the nineteenth and early twentieth centuries and brought to Berlin in the name of science. The debates crystallise how deeply divided German scientific discourses still are over the question of whether the historical and moral obligations of colonial injustice should be accepted or whether researchers should continue to profess scientific disinterest'. The debates also reveal an almost unanimous disavowal of Indigenous Australian knowledges and mnemonic conceptions across all camps. The bitter ironies of this disavowal become evident when Indigenous Australian quests for the remains of their ancestral dead lost in the limbo of German scientific collections are juxtaposed with white Australian (fictional) quests for the remains of Ludwig Leichhardt, lost in the Australian interior. T3 - Zweitveröffentlichungen der Universität Potsdam : Philosophische Reihe - 147 KW - memory KW - ancestral remains KW - museums and anthropological collections KW - restorative justice KW - indigenous knowledge KW - Ludwig Leichhardt Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-413654 ER - TY - GEN A1 - Eckstein, Lars A1 - Schwarz, Anja T1 - The Making of Tupaia’s Map BT - a Story of the Extent and Mastery of Polynesian Navigation, Competing Systems of Wayfinding on James Cook’s Endeavour, and the Invention of an Ingenious Cartographic System T2 - Postprints der Universität Potsdam Philosophische Reihe N2 - Tupaia’s Map is one of the most famous and enigmatic artefacts to emerge from the early encounters between Europeans and Pacific Islanders. It was drawn by Tupaia, an arioi priest, chiefly advisor and master navigator from Ra‘iātea in the Leeward Society Islands in collaboration with various members of the crew of James Cook’s Endeavour, in two distinct moments of mapmaking and three draft stages between August 1769 and February 1770. To this day, the identity of many islands on the chart, and the logic of their arrangement have posed a riddle to researchers. Drawing in part on archival material hitherto overlooked, in this long essay we propose a new understanding of the chart’s cartographic logic, offer a detailed reconstruction of its genesis, and thus for the first time present a comprehensive reading of Tupaia’s Map. The chart not only underscores the extent and mastery of Polynesian navigation, it is also a remarkable feat of translation between two very different wayfinding systems and their respective representational models. T3 - Zweitveröffentlichungen der Universität Potsdam : Philosophische Reihe - 154 KW - artography KW - first contact KW - wayfinding KW - star navigation KW - sea of islands KW - translation KW - Indigenous knowledges and ontologies KW - Tupaia Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-423091 SN - 1866-8380 IS - 154 ER - TY - GEN A1 - Puppe, Daniel A1 - Wanner, Manfred A1 - Sommer, Michael T1 - Data on euglyphid testate amoeba densities, corresponding protozoic silicon pools, and selected soil parameters of initial and forested biogeosystems T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The dataset in the present article provides information on protozoic silicon (Si) pools represented by euglyphid testate amoebae (TA) in soils of initial and forested biogeosystems. Protozoic Si pools were calculated from densities of euglyphid TA shells and corresponding Si contents. The article also includes data on potential annual biosilicification rates of euglyphid TA at the examined sites. Furthermore, data on selected soil parameters (e.g., readily-available Si, soil pH) and site characteristics (e.g., soil groups, climate data) can be found. The data might be interesting for researchers focusing on biological processes in Si cycling in general and euglyphid TA and corresponding protozoic Si pools in particular. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1039 KW - silicon cycling KW - biogenic silica KW - terrestrial biogeosystems KW - biosilicification KW - Euglyphida Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-471160 SN - 1866-8372 IS - 1039 ER - TY - GEN A1 - Schönemann, Eric A1 - Laschewsky, André A1 - Rosenhahn, Axel T1 - Exploring the long-term hydrolytic behavior of zwitterionic polymethacrylates and polymethacrylamides T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The hydrolytic stability of polymers to be used for coatings in aqueous environments, for example, to confer anti-fouling properties, is crucial. However, long-term exposure studies on such polymers are virtually missing. In this context, we synthesized a set of nine polymers that are typically used for low-fouling coatings, comprising the well-established poly(oligoethylene glycol methylether methacrylate), poly(3-(N-2-methacryloylethyl-N,N-dimethyl) ammoniopropanesulfonate) (“sulfobetaine methacrylate”), and poly(3-(N-3-methacryamidopropyl-N,N-dimethyl)ammoniopropanesulfonate) (“sulfobetaine methacrylamide”) as well as a series of hitherto rarely studied polysulfabetaines, which had been suggested to be particularly hydrolysis-stable. Hydrolysis resistance upon extended storage in aqueous solution is followed by ¹H NMR at ambient temperature in various pH regimes. Whereas the monomers suffered slow (in PBS) to very fast hydrolysis (in 1 M NaOH), the polymers, including the polymethacrylates, proved to be highly stable. No degradation of the carboxyl ester or amide was observed after one year in PBS, 1 M HCl, or in sodium carbonate buffer of pH 10. This demonstrates their basic suitability for anti-fouling applications. Poly(sulfobetaine methacrylamide) proved even to be stable for one year in 1 M NaOH without any signs of degradation. The stability is ascribed to a steric shielding effect. The hemisulfate group in the polysulfabetaines, however, was found to be partially labile. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1091 KW - polyzwitterions KW - stability KW - polymer degradation KW - hydrolysis KW - polysulfobetaine KW - polysulfabetaine KW - anti-fouling materials Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-473052 SN - 1866-8372 IS - 1091 ER - TY - GEN A1 - Shan, Yuli A1 - Guan, Dabo A1 - Hubacek, Klaus A1 - Zheng, Bo A1 - Davis, Steven J. A1 - Jia, Lichao A1 - Liu, Jianghua A1 - Liu, Zhu A1 - Fromer, Neil A1 - Mi, Zhifu A1 - Meng, Jing A1 - Deng, Xiangzheng A1 - Li, Yuan A1 - Lin, Jintai A1 - Schroeder, Heike A1 - Weisz, Helga A1 - Schellnhuber, Hans Joachim T1 - City-level climate change mitigation in China T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - As national efforts to reduce CO2 emissions intensify, policy-makers need increasingly specific, subnational information about the sources of CO2 and the potential reductions and economic implications of different possible policies. This is particularly true in China, a large and economically diverse country that has rapidly industrialized and urbanized and that has pledged under the Paris Agreement that its emissions will peak by 2030. We present new, city level estimates of CO2 emissions for 182 Chinese cities, decomposed into 17 different fossil fuels, 46 socioeconomic sectors, and 7 industrial processes. We find that more affluent cities have systematically lower emissions per unit of gross domestic product (GDP), supported by imports from less affluent, industrial cities located nearby. In turn, clusters of industrial cities are supported by nearby centers of coal or oil extraction. Whereas policies directly targeting manufacturing and electric power infrastructure would drastically undermine the GDP of industrial cities, consumption based policies might allow emission reductions to be subsidized by those with greater ability to pay. In particular, sector based analysis of each city suggests that technological improvements could be a practical and effective means of reducing emissions while maintaining growth and the current economic structure and energy system. We explore city-level emission reductions under three scenarios of technological progress to show that substantial reductions (up to 31%) are possible by updating a disproportionately small fraction of existing infrastructure. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1096 KW - carbon-dioxide emissions KW - fired power plants KW - co2 emissions KW - energy use KW - cluster analysis KW - uncertainties KW - urbanization KW - methodology KW - combustion KW - inventory Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-471541 SN - 1866-8372 IS - 1096 ER - TY - GEN A1 - Schulze, Sven A1 - Wehrhold, Michel A1 - Hille, Carsten T1 - Femtosecond-pulsed laser written and etched fiber bragg gratings for fiber-optical biosensing T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - We present the development of a label-free, highly sensitive fiber-optical biosensor for online detection and quantification of biomolecules. Here, the advantages of etched fiber Bragg gratings (eFBG) were used, since they induce a narrowband Bragg wavelength peak in the reflection operation mode. The gratings were fabricated point-by-point via a nonlinear absorption process of a highly focused femtosecond-pulsed laser, without the need of prior coating removal or specific fiber doping. The sensitivity of the Bragg wavelength peak to the surrounding refractive index (SRI), as needed for biochemical sensing, was realized by fiber cladding removal using hydrofluoric acid etching. For evaluation of biosensing capabilities, eFBG fibers were biofunctionalized with a single-stranded DNA aptamer specific for binding the C-reactive protein (CRP). Thus, the CRP-sensitive eFBG fiber-optical biosensor showed a very low limit of detection of 0.82 pg/L, with a dynamic range of CRP detection from approximately 0.8 pg/L to 1.2 µg/L. The biosensor showed a high specificity to CRP even in the presence of interfering substances. These results suggest that the proposed biosensor is capable for quantification of CRP from trace amounts of clinical samples. In addition, the adaption of this eFBG fiber-optical biosensor for detection of other relevant analytes can be easily realized. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1073 KW - fiber Bragg gratings KW - ultra-fast laser inscription KW - fiber etching KW - nanostructure fabrication KW - fiber-optical sensors KW - aptamers KW - C-reactive Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472692 SN - 1866-8372 IS - 1073 ER - TY - GEN A1 - Marrucci, Monica A1 - Zeilinger, Gerold A1 - Ribolini, Adriano A1 - Schwanghart, Wolfgang T1 - Origin of knickpoints in an alpine context subject to different perturbing factors, Stura Valley, Maritime Alps (North-Western Italy) T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Natural catchments are likely to show the existence of knickpoints in their river networks. The origin and genesis of the knickpoints can be manifold, considering that the present morphology is the result of the interactions of different factors such as tectonic movements, quaternary glaciations, river captures, variable lithology, and base-level changes. We analyzed the longitudinal profiles of the river channels in the Stura di Demonte Valley (Maritime Alps) to identify the knickpoints of such an alpine setting and to characterize their origins. The distribution and the geometry of stream profiles were used to identify the possible causes of the changes in stream gradients and to define zones with genetically linked knickpoints. Knickpoints are key geomorphological features for reconstructing the evolution of fluvial dissected basins, when the different perturbing factors affecting the ideally graded fluvial system have been detected. This study shows that even in a regionally small area, perturbations of river profiles are caused by multiple factors. Thus, attributing (automatically)-extracted knickpoints solely to one factor, can potentially lead to incomplete interpretations of catchment evolution. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1070 KW - knickpoint KW - river longitudinal profile KW - Maritime Alps Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472642 SN - 1866-8372 IS - 1070 ER - TY - GEN A1 - Kleuser, Burkhard T1 - The enigma of sphingolipids in health and disease T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1040 KW - sphingosine-1-phosphate Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472637 SN - 1866-8372 IS - 1040 ER - TY - GEN A1 - Gabriel, Marvin A1 - Toader, Camelia A1 - Faul, Franziska A1 - Rosskopf, Niko A1 - Grundling, Piet-Louis A1 - Van Huyssteen, Cornelius W. A1 - Grundling, Althea T. A1 - Zeitz, Jutta T1 - Physical and hydrological properties of peat as proxies for degradation of South African peatlands BT - Implications for conservation and restoration T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The physical and hydrological properties of peat from seven peatlands in northern Maputaland (South Africa) were investigated and related to the degradation processes of peatlands in different hydrogeomorphic settings. The selected peatlands are representative of typical hydrogeomorphic settings and different stages of human modification from natural to severely degraded. Nineteen transects (141 soil corings in total) were examined in order to describe peat properties typical of the distinct hydrogeomorphic settings. We studied degree of decomposition, organic matter content, bulk density, water retention, saturated hydraulic conductivity and hydrophobicity of the peats. From these properties we derived pore size distribution, unsaturated hydraulic conductivity and maximum capillary rise. We found that, after drainage, degradation advances faster in peatlands containing wood peat than in peatlands containing radicell peat. Eucalyptus plantations in catchment areas are especially threatening to peatlands in seeps, interdune depressions and unchannelled valley bottoms. All peatlands and their recharge areas require wise management, especially valley-bottom peatlands with swamp forest vegetation. Blocking drainage ditches is indispensable as a first step towards achieving the restoration of drained peatland areas, and further measures may be necessary to enhance the distribution of water. The sensitive swamp forest ecosystems should be given conservation priority. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1103 KW - moorsh forming process KW - swamp forest KW - restoration KW - unsaturated hydraulic conductivity Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-470514 SN - 1866-8372 IS - 1103 ER - TY - GEN A1 - Afantenos, Stergos A1 - Peldszus, Andreas A1 - Stede, Manfred T1 - Comparing decoding mechanisms for parsing argumentative structures T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Parsing of argumentative structures has become a very active line of research in recent years. Like discourse parsing or any other natural language task that requires prediction of linguistic structures, most approaches choose to learn a local model and then perform global decoding over the local probability distributions, often imposing constraints that are specific to the task at hand. Specifically for argumentation parsing, two decoding approaches have been recently proposed: Minimum Spanning Trees (MST) and Integer Linear Programming (ILP), following similar trends in discourse parsing. In contrast to discourse parsing though, where trees are not always used as underlying annotation schemes, argumentation structures so far have always been represented with trees. Using the 'argumentative microtext corpus' [in: Argumentation and Reasoned Action: Proceedings of the 1st European Conference on Argumentation, Lisbon 2015 / Vol. 2, College Publications, London, 2016, pp. 801-815] as underlying data and replicating three different decoding mechanisms, in this paper we propose a novel ILP decoder and an extension to our earlier MST work, and then thoroughly compare the approaches. The result is that our new decoder outperforms related work in important respects, and that in general, ILP and MST yield very similar performance. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1062 KW - argumentation structure KW - argument mining KW - parsing Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-470527 SN - 1866-8372 IS - 1062 ER - TY - GEN A1 - Coesfeld, Jacqueline A1 - Anderson, Sharolyn J. A1 - Baugh, Kimberly A1 - Elvidge, Christopher D. A1 - Schernthanner, Harald A1 - Kyba, Christopher C. M. T1 - Variation of individual location radiance in VIIRS DNB monthly composite images T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - With the growing size and use of night light time series from the Visible Infrared Imaging Radiometer Suite Day/Night Band (DNB), it is important to understand the stability of the dataset. All satellites observe differences in pixel values during repeat observations. In the case of night light data, these changes can be due to both environmental effects and changes in light emission. Here we examine the stability of individual locations of particular large scale light sources (e.g., airports and prisons) in the monthly composites of DNB data from April 2012 to September 2017. The radiances for individual pixels of most large light emitters are approximately normally distributed, with a standard deviation of typically 15-20% of the mean. Greenhouses and flares, however, are not stable sources. We observe geospatial autocorrelation in the monthly variations for nearby sites, while the correlation for sites separated by large distances is small. This suggests that local factors contribute most to the variation in the pixel radiances and furthermore that averaging radiances over large areas will reduce the total variation. A better understanding of the causes of temporal variation would improve the sensitivity of DNB to lighting changes. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1113 KW - artificial light at night KW - light pollution KW - night lights KW - VIIRS DNB Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472326 SN - 1866-8372 IS - 1113 ER - TY - GEN A1 - Gräf, Ralph T1 - Comparative biology of centrosomal structures in eukaryotes T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The centrosome is not only the largest and most sophisticated protein complex within a eukaryotic cell, in the light of evolution, it is also one of its most ancient organelles. This special issue of "Cells" features representatives of three main, structurally divergent centrosome types, i.e., centriole-containing centrosomes, yeast spindle pole bodies (SPBs), and amoebozoan nucleus-associated bodies (NABs). Here, I discuss their evolution and their key-functions in microtubule organization, mitosis, and cytokinesis. Furthermore, I provide a brief history of centrosome research and highlight recently emerged topics, such as the role of centrioles in ciliogenesis, the relationship of centrosomes and centriolar satellites, the integration of centrosomal structures into the nuclear envelope and the involvement of centrosomal components in non-centrosomal microtubule organization. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1063 KW - centrosome KW - centriole KW - cilium KW - basal body KW - spindle pole body KW - SPB KW - nucleus-associated body KW - NAB KW - microtubules Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-472294 SN - 1866-8372 IS - 1063 ER - TY - GEN A1 - Nakamura, Moritaka A1 - Claes, Andrea R. A1 - Grebe, Tobias A1 - Hermkes, Rebecca A1 - Viotti, Corrado A1 - Ikeda, Yoshihisa A1 - Grebe, Markus T1 - Auxin and ROP GTPase signaling of polar nuclear migration in root epidermal hair cells T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Polar nuclear migration is crucial during the development of diverse eukaryotes. In plants, root hair growth requires polar nuclear migration into the outgrowing hair. However, knowledge about the dynamics and the regulatory mechanisms underlying nuclear movements in root epidermal cells remains limited. Here, we show that both auxin and Rho-of-Plant (ROP) signaling modulate polar nuclear position at the inner epidermal plasma membrane domain oriented to the cortical cells during cell elongation as well as subsequent polar nuclear movement to the outer domain into the emerging hair bulge in Arabidopsis (Arabidopsis thaliana). Auxin signaling via the nuclear AUXIN RESPONSE FACTOR7 (ARF7)/ARF19 and INDOLE ACETIC ACID7 pathway ensures correct nuclear placement toward the inner membrane domain. Moreover, precise inner nuclear placement relies on SPIKE1 Rho-GEF, SUPERCENTIPEDE1 Rho-GDI, and ACTIN7 (ACT7) function and to a lesser extent on VTI11 vacuolar SNARE activity. Strikingly, the directionality and/or velocity of outer polar nuclear migration into the hair outgrowth along actin strands also are ACT7 dependent, auxin sensitive, and regulated by ROP signaling. Thus, our findings provide a founding framework revealing auxin and ROP signaling of inner polar nuclear position with some contribution by vacuolar morphology and of actin-dependent outer polar nuclear migration in root epidermal hair cells. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 992 KW - Arabidopsis-thaliana KW - planar polarity KW - tip growth KW - morphogenesis KW - gene KW - proteins KW - dynamics KW - transformation KW - activation KW - initiation Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-441278 SN - 1866-8372 IS - 992 SP - 378 EP - 391 ER - TY - GEN A1 - Nakamura, Moritaka A1 - Grebe, Markus T1 - Outer, inner and planar polarity in the Arabidopsis root T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Plant roots control uptake of water and nutrients and cope with environmental challenges. The root epidermis provides the first selective interface for nutrient absorption, while the endodermis produces the main apoplastic diffusion barrier in the form of a structure called the Casparian strip. The positioning of root hairs on epidermal cells, and of the Casparian strip around endodermal cells, requires asymmetries along cellular axes (cell polarity). Cell polarity is termed planar polarity, when coordinated within the plane of a given tissue layer. Here, we review recent molecular advances towards understanding both the polar positioning of the proteo-lipid membrane domain instructing root hair initiation, and the cytoskeletal, trafficking and polar tethering requirements of proteins at outer or inner plasma membrane domains. Finally, we highlight progress towards understanding mechanisms of Casparian strip formation and underlying endodermal cell polarity. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 911 KW - binding cassette transporter KW - casparian strip formation KW - boric-acid channel KW - cell polarity KW - plasma-membrane KW - tip growth KW - hair development KW - soil interface KW - ROP2 GTPASE KW - D-galactose Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-441266 SN - 1866-8372 IS - 911 SP - 46 EP - 53 ER - TY - GEN A1 - Götz, Antonia A1 - Yeung, H. Henny A1 - Krasotkina, Anna A1 - Schwarzer, Gudrun A1 - Höhle, Barbara T1 - Perceptual Reorganization of Lexical Tones BT - Effects of Age and Experimental Procedure T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Findings on the perceptual reorganization of lexical tones are mixed. Some studies report good tone discrimination abilities for all tested age groups, others report decreased or enhanced discrimination with increasing age, and still others report U-shaped developmental curves. Since prior studies have used a wide range of contrasts and experimental procedures, it is unclear how specific task requirements interact with discrimination abilities at different ages. In the present work, we tested German and Cantonese adults on their discrimination of Cantonese lexical tones, as well as German-learning infants between 6 and 18 months of age on their discrimination of two specific Cantonese tones using two different types of experimental procedures. The adult experiment showed that German native speakers can discriminate between lexical tones, but native Cantonese speakers show significantly better performance. The results from German-learning infants suggest that 6- and 18-month-olds discriminate tones, while 9-month-olds do not, supporting a U-shaped developmental curve. Furthermore, our results revealed an effect of methodology, with good discrimination performance at 6 months after habituation but not after familiarization. These results support three main conclusions. First, habituation can be a more sensitive procedure for measuring infants' discrimination than familiarization. Second, the previous finding of a U-shaped curve in the discrimination of lexical tones is further supported. Third, discrimination abilities at 18 months appear to reflect mature perceptual sensitivity to lexical tones, since German adults also discriminated the lexical tones with high accuracy. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 433 KW - perceptual reorganization KW - lexical tones KW - U-shaped curve KW - habituation KW - familiarization Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-411759 IS - 433 ER - TY - GEN A1 - Kühne, Franziska A1 - Lesser, Hannah A1 - Petri, Franziska A1 - Weck, Florian T1 - Do mental health patients learn what their cognitive-behaviour therapists think they do? BT - a short report on qualitative interviews comparing perspectives T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Purpose: The acquisition of skills is essential to the conceptualization of cognitive-behavioural therapy. Yet, what experiences are encountered and what skills actually learned during therapy, and whether patients and therapists have concurrent views hereof, remains poorly understood. Method: An explorative pilot study with semi-structured, corresponding interview guides was conducted. Pilot data from our outpatient unit were transcribed and content-analyzed following current guidelines. Results: The responses of 18 participants (patients and their psychotherapists) were assigned to six main categories. Educational and cognitive aspects were mentioned most frequently and consistently by both groups. Having learned Behavioural alternatives attained the second highest agreement between perspectives. Conclusions: Patients and therapists valued CBT as an opportunity to learn new skills, which is an important prerequisite also for the maintenance of therapeutic change. We discuss limitations to generalizability but also theoretical and therapy implications. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 490 KW - cognitive-behavioural therapy (CBT) KW - psychotherapy KW - interview study KW - learning KW - skills Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-420607 SN - 1866-8364 IS - 490 ER - TY - GEN A1 - Ijiri, Akira A1 - Inagaki, Fumio A1 - Kubo, Yusuke A1 - Adhikari, Rishi Ram A1 - Hattori, Shohei A1 - Hoshino, Tatsuhiko A1 - Imachi, Hiroyuki A1 - Kawagucci, Shinsuke A1 - Morono, Yuki A1 - Ohtomo, Yoko A1 - Ono, Shuhei A1 - Sakai, Sanae A1 - Takai, Ken A1 - Toki, Tomohiro A1 - Wang, David T. A1 - Yoshinaga, Marcos Y. A1 - Arnold, Gail L. A1 - Ashi, Juichiro A1 - Case, David H. A1 - Feseker, Tomas A1 - Hinrichs, Kai-Uwe A1 - Ikegawa, Yojiro A1 - Ikehara, Minoru A1 - Kallmeyer, Jens A1 - Kumagai, Hidenori A1 - Lever, Mark Alexander A1 - Morita, Sumito A1 - Nakamura, Ko-ichi A1 - Nakamura, Yuki A1 - Nishizawa, Manabu A1 - Orphan, Victoria J. A1 - Røy, Hans A1 - Schmidt, Frauke A1 - Tani, Atsushi A1 - Tanikawa, Wataru A1 - Terada, Takeshi A1 - Tomaru, Hitoshi A1 - Tsuji, Takeshi A1 - Tsunogai, Urumu A1 - Yamaguchi, Yasuhiko T. A1 - Yoshida, Naohiro T1 - Deep-biosphere methane production stimulated by geofluids in the Nankai accretionary complex T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Microbial life inhabiting subseafloor sediments plays an important role in Earth’s carbon cycle. However, the impact of geodynamic processes on the distributions and carbon-cycling activities of subseafloor life remains poorly constrained. We explore a submarine mud volcano of the Nankai accretionary complex by drilling down to 200 m below the summit. Stable isotopic compositions of water and carbon compounds, including clumped methane isotopologues, suggest that ~90% of methane is microbially produced at 16° to 30°C and 300 to 900 m below seafloor, corresponding to the basin bottom, where fluids in the accretionary prism are supplied via megasplay faults. Radiotracer experiments showed that relatively small microbial populations in deep mud volcano sediments (10 2 to 10 3 cells cm −3 ) include highly active hydrogenotrophic methanogens and acetogens. Our findings indicate that subduction-associated fluid migration has stimulated microbial activity in the mud reservoir and that mud volcanoes may contribute more substantially to the methane budget than previously estimated. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 802 KW - multiply-substituted isotopologues KW - marine subsurface sediments KW - carbon isotopic composition KW - submarine mud volcano KW - intact polar lipids KW - fore-arc basin KW - subseafloor sediments KW - microbial lipids KW - Cascadia margin KW - organic-acids Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427002 SN - 1866-8372 IS - 802 ER - TY - GEN A1 - Otto, Nils A1 - Marelja, Zvonimir A1 - Schoofs, Andreas A1 - Kranenburg, Holger A1 - Bittern, Jonas A1 - Yildirim, Kerem A1 - Berh, Dimitri A1 - Bethke, Maria A1 - Thomas, Silke A1 - Rode, Sandra A1 - Risse, Benjamin A1 - Jiang, Xiaoyi A1 - Pankratz, Michael A1 - Leimkühler, Silke A1 - Klämbt, Christian T1 - The sulfite oxidase Shopper controls neuronal activity by regulating glutamate homeostasis in Drosophila ensheathing glia T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - Specialized glial subtypes provide support to developing and functioning neural networks. Astrocytes modulate information processing by neurotransmitter recycling and release of neuromodulatory substances, whereas ensheathing glial cells have not been associated with neuromodulatory functions yet. To decipher a possible role of ensheathing glia in neuronal information processing, we screened for glial genes required in the Drosophila central nervous system for normal locomotor behavior. Shopper encodes a mitochondrial sulfite oxidase that is specifically required in ensheathing glia to regulate head bending and peristalsis. shopper mutants show elevated sulfite levels affecting the glutamate homeostasis which then act on neuronal network function. Interestingly, human patients lacking the Shopper homolog SUOX develop neurological symptoms, including seizures. Given an enhanced expression of SUOX by oligodendrocytes, our findings might indicate that in both invertebrates and vertebrates more than one glial cell type may be involved in modulating neuronal activity. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 975 KW - molybdenum cofactor deficiency KW - blood-brain-barrier KW - larval locomotion KW - energy-metabolism KW - cerebral-cortex KW - astrocytes KW - behavior KW - cells KW - transmission KW - disease KW - Diseases of the nervous system KW - Glial biology KW - Glial development KW - Neurotransmitters Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426205 SN - 1866-8372 IS - 975 ER - TY - GEN A1 - Unterberger, Christian A1 - Hudson, Paul A1 - Botzen, W. J. Wouter A1 - Schroeer, Katharina A1 - Steininger, Karl W. T1 - Future public sector flood risk and risk sharing arrangements BT - an assessment for Austria T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Climate change, along with socio-economic development, will increase the economic impacts of floods. While the factors that influence flood risk to private property have been extensively studied, the risk that natural disasters pose to public infrastructure and the resulting implications on public sector budgets, have received less attention. We address this gap by developing a two-staged model framework, which first assesses the flood risk to public infrastructure in Austria. Combining exposure and vulnerability information at the building level with inundation maps, we project an increase in riverine flood damage, which progressively burdens public budgets. Second, the risk estimates are integrated into an insurance model, which analyzes three different compensation arrangements in terms of the monetary burden they place on future governments' budgets and the respective volatility of payments. Formalized insurance compensation arrangements offer incentives for risk reduction measures, which lower the burden on public budgets by reducing the vulnerability of buildings that are exposed to flooding. They also significantly reduce the volatility of payments and thereby improve the predictability of flood damage expenditures. These features indicate that more formalized insurance arrangements are an improvement over the purely public compensation arrangement currently in place in Austria. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 634 KW - climate change KW - adaptation KW - flood risk KW - insurance KW - public sector KW - risk reduction Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-424629 SN - 1866-8372 IS - 634 ER - TY - GEN A1 - Ventura-Bort, Carlos A1 - Wirkner, Janine A1 - Genheimer, Hannah A1 - Wendt, Julia A1 - Hamm, Alfons O. A1 - Weymar, Mathias T1 - Effects of Transcutaneous Vagus Nerve Stimulation (tVNS) on the P300 and Alpha-Amylase Level BT - A Pilot Study T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - Recent research suggests that the P3b may be closely related to the activation of the locus coeruleus-norepinephrine (LC-NE) system. To further study the potential association, we applied a novel technique, the non-invasive transcutaneous vagus nerve stimulation (tVNS), which is speculated to increase noradrenaline levels. Using a within-subject cross-over design, 20 healthy participants received continuous tVNS and sham stimulation on two consecutive days (stimulation counterbalanced across participants) while performing a visual oddball task. During stimulation, oval non-targets (standard), normal-head (easy) and rotated-head (difficult) targets, as well as novel stimuli (scenes) were presented. As an indirect marker of noradrenergic activation we also collected salivary alpha-amylase (sAA) before and after stimulation. Results showed larger P3b amplitudes for target, relative to standard stimuli, irrespective of stimulation condition. Exploratory post hoc analyses, however, revealed that, in comparison to standard stimuli, easy (but not difficult) targets produced larger P3b (but not P3a) amplitudes during active tVNS, compared to sham stimulation. For sAA levels, although main analyses did not show differential effects of stimulation, direct testing revealed that tVNS (but not sham stimulation) increased sAA levels after stimulation. Additionally, larger differences between tVNS and sham stimulation in P3b magnitudes for easy targets were associated with larger increase in sAA levels after tVNS, but not after sham stimulation. Despite preliminary evidence for a modulatory influence of tVNS on the P3b, which may be partly mediated by activation of the noradrenergic system, additional research in this field is clearly warranted. Future studies need to clarify whether tVNS also facilitates other processes, such as learning and memory, and whether tVNS can be used as therapeutic tool. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 473 KW - EEG KW - P300 KW - tVNS KW - norepinephrine KW - locus coeruleus KW - salivary alpha-amylase Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419259 IS - 473 ER - TY - GEN A1 - Mischke, Dennis T1 - A universal, uniform humanity BT - the German newspaper Der Kosmopolit and entangled nation-building in nineteenth-century Australia T2 - Postcolonial Studies N2 - The focus in this article, through a reading of the German-Australian newspaper Der Kosmopolit, is on the legacies of entangled imperial identities in the period of the nineteenth-century German Enlightenment. Attention is drawn to members of the liberal nationalist generation of 1848 who emigrated to the Australian colonies and became involved in intellectual activities there. The idea of entanglement is applied to the philosophical orientation of the German-language newspaper that this group formed, Der Kosmopolit, which was published between 1856 and 1957. Against simplistic notions that would view cosmopolitanism as the opposite of nationalism, it is argued that individuals like Gustav Droege and Carl Muecke deployed an entangled ‘cosmo- nationalism’ in ways that both advanced German nationalism and facilitated their own engagement with and investment in Australian colonial society. T3 - Zweitveröffentlichungen der Universität Potsdam : Philosophische Reihe - 142 KW - German-Australian entanglements KW - German colonialism KW - cosmopolitanism and nationalism KW - nineteenth- century newspapers KW - Carl Muecke Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412942 ER - TY - GEN A1 - Schwarz, Anja T1 - Schomburgk’s Chook BT - the entangled South Australian collections of a German naturalist T2 - Postprints der Universität Potsdam : Philosophische Reihe N2 - Focusing on the politics of museums, collections and the untold stories of the scientific ‘specimens’ that travelled between Germany and Australia, this article reconstructs the historical, interpersonal and geopolitical contexts that made it possible for the stuffed skin of an Australian malleefowl to become part of the collections of Berlin’s Museum für Naturkunde. The author enquires into the kinds of contexts that are habitually considered irrelevant when a specimen of natural history is treated as an object of taxonomic information only. In case of this particular specimen human and non-human history become entangled in ways that link the fate of this one small Australian bird to the German revolutionary generation of 1848, to Germany’s nineteenth-century colonial aspirations, to settler–Indigenous relations, to the cruel realities that underpinned the production of scientific knowledge in colonial Australia, and to a present-day interest in reconstructing Indigenous knowledges. T3 - Zweitveröffentlichungen der Universität Potsdam : Philosophische Reihe - 141 KW - German colonialism KW - colonial Australia KW - natural history collections KW - Richard Schomburgk KW - malleefowl (Leipoa ocellata) Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412959 SN - 1866-8380 IS - 141 ER - TY - GEN A1 - Pathe-Neuschäfer-Rube, Andrea A1 - Neuschäfer-Rube, Frank A1 - Haas, Gerald A1 - Langoth-Fehringer, Nina A1 - Püschel, Gerhard Paul T1 - Cell-Based Reporter Release Assay to Determine the Potency of Proteolytic Bacterial Neurotoxins T2 - Toxins N2 - Despite the implementation of cell-based replacement methods, the mouse lethality assay is still frequently used to determine the activity of botulinum toxin (BoNT) for medical use. One explanation is that due to the use of neoepitope-specific antibodies to detect the cleaved BoNT substrate, the currently devised assays can detect only one specific serotype of the toxin. Recently, we developed a cell-based functional assay, in which BoNT activity is determined by inhibiting the release of a reporter enzyme that is liberated concomitantly with the neurotransmitter from neurosecretory vesicles. In theory, this assay should be suitable to detect the activity of any BoNT serotype. Consistent with this assumption, the current study shows that the stimulus-dependent release of a luciferase from a differentiated human neuroblastoma-based reporter cell line (SIMA-hPOMC1-26-GLuc cells) was inhibited by BoNT-A and-C. Furthermore, this was also inhibited by BoNT-B and tetanus toxin to a lesser extent and at higher concentrations. In order to provide support for the suitability of this technique in practical applications, a dose–response curve obtained with a pharmaceutical preparation of BoNT-A closely mirrored the activity determined in the mouse lethality assay. In summary, the newly established cell-based assay may represent a versatile and specific alternative to the mouse lethality assay and other currently established cell-based assays. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 473 KW - botulinum toxin KW - BoNT KW - tetanus toxin KW - RRR KW - replacement Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-418141 ER - TY - GEN A1 - Henkel, Janin A1 - Coleman Mac Gregor of Inneregny, Charles Dominic A1 - Schraplau, Anne A1 - Jöhrens, Korinna A1 - Weiss, Thomas Siegfried A1 - Jonas, Wenke A1 - Schürmann, Annette A1 - Püschel, Gerhard Paul T1 - Augmented liver inflammation in a microsomal prostaglandin E synthase 1 (mPGES-1)-deficient diet-induced mouse NASH model T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - In a subset of patients, non-alcoholic fatty liver disease (NAFLD) is complicated by cell death and inflammation resulting in non-alcoholic steatohepatitis (NASH), which may progress to fibrosis and subsequent organ failure. Apart from cytokines, prostaglandins, in particular prostaglandin E-2 (PGE(2)), play a pivotal role during inflammatory processes. Expression of the key enzymes of PGE(2) synthesis, cyclooxygenase 2 and microsomal PGE synthase 1 (mPGES-1), was increased in human NASH livers in comparison to controls and correlated with the NASH activity score. Both enzymes were also induced in NASH-diet-fed wild-type mice, resulting in an increase in hepatic PGE(2) concentration that was completely abrogated in mPGES-1-deficient mice. PGE(2) is known to inhibit TNF-alpha synthesis in macrophages. A strong infiltration of monocyte-derived macrophages was observed in NASH-diet-fed mice, which was accompanied with an increase in hepatic TNF-alpha expression. Due to the impaired PGE(2) production, TNF-alpha expression increased much more in livers of mPGES-1-deficient mice or in the peritoneal macrophages of these mice. The increased levels of TNF-alpha resulted in an enhanced IL-1 beta production, primarily in hepatocytes, and augmented hepatocyte apoptosis. In conclusion, attenuation of PGE(2) production by mPGES-1 ablation enhanced the TNF-alpha-triggered inflammatory response and hepatocyte apoptosis in diet-induced NASH. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 483 KW - suppress VLDL secretion KW - mice lacking KW - nonalcoholic steatohepatthis KW - insulin-resistance KW - rat hepatocytes KW - kupffer cells KW - E-2 KW - disease KW - expression KW - accumulation Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-420879 SN - 1866-8372 IS - 483 ER - TY - JOUR A1 - Thulin, Mirjam A1 - Krah, Markus T1 - Disciplining Jewish Knowledge BT - Cultures of Wissenschaft des Judentums at 200 JF - PaRDES : Zeitschrift der Vereinigung für Jüdische Studien e. V. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-417743 SP - 9 EP - 16 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Albeck-Gidron, Rachel T1 - At Opposite Ends of Asia – Contact between East Asian Culture and Modern Hebrew Literature from the Late Nineteenth Century until Today. A Historiographical and Linguistic Study JF - Sprache Deutsch PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien [23 (2017)] = JewBus, Jewish Hindus & other Jewish Encounters with East Asian Religions JF - PaRDeS : Journal of the Association of Jewish Studies [23 (2017)] = JewBus, Jewish Hindus & other Jewish Encounters with East Asian Religions N2 - This article deals with contact between East Asian thought and modern Hebrew Literature from the late nineteenth century through the twentieth century, until today. In the first part, the article suggests that from a historiographical perspective, one may outline three waves of contact between these two cultural phenomena, at opposite ends of Asia. In the first wave, which began in the early twentieth century, Asian influence on Hebrew literature written in Europe was mediated mainly through the philosophers Schopenhauer and Nietzsche. The second wave, which emerged in the 1950s, relates to the influence of the leaders of the Beat Generation, who, in turn, were influenced by modernist poetry in English, which was colored by contact with Asian poetry. The third wave is part of the glocal New Age phenomenon and its appropriation of certain Buddhist traits. The second part of the article presents several theoretical possibilities of symbioses between cultures, as they appear within language. The third part presents the symptomatic example of the work of contemporary Hebrew writer Yoel Hoffmann, who appears to be a representative of the second wave; however, his work maintains dialogue with the first wave, and its current popularity is part of the third wave. Hoffmann’s work serves as an example of how to apply the theoretical possibilities presented in the second part of the article, as an instance of literary contact between two cultures and their respective languages. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-408931 SN - 978-3-86956-418-0 SN - 1614-6492 SN - 1862-7684 IS - 23 SP - 95 EP - 118 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - THES A1 - Valliappan, Senthamizh Pavai T1 - Solar Activity Reconstruction from Historical Observations of Sunspots T1 - Rekonstruktion der Sonnenaktivität aus historischen Beobachtungen von Sonnenflecken N2 - The solar activity and its consequences affect space weather and Earth’s climate. The solar activity exhibits a cyclic behaviour with a period of about 11 years. The solar cycle properties are governed by the dynamo taking place in the interior of the Sun, and they are distinctive. Extending the knowledge about solar cycle properties into the past is essential for understanding the solar dynamo and forecasting space weather. It can be acquired through the analysis of historical sunspot drawings. Sunspots are the dark areas, which are associated with strong magnetic fields, on the solar surface. Sunspots are the oldest and longest available observed features of solar activity. One of the longest available records of sunspot drawings is the collection by Samuel Heinrich Schwabe during 1825–1867. The sunspot sizes measured from digitized Schwabe drawings are not to scale and need to be converted into physical sunspot areas. We employed a statistical approach assuming that the area distribution of sunspots was the same in the 19th century as it was in the 20th century. Umbral areas for about 130 000 sunspots observed by Schwabe were obtained. The annually averaged sunspot areas correlate reasonably well with the sunspot number. Tilt angles and polarity separations of sunspot groups were calculated assuming them to be bipolar. There is, of course, no polarity information in the observations. We derived an average tilt angle by attempting to exclude unipolar groups with a minimum separation of the two surmised polarities and an outlier rejection method, which follows the evolution of each group and detects the moment, when it turns unipolar as it decays. As a result, the tilt angles, although displaying considerable natural scatter, are on average 5.85° ± 0.25°, with the leading polarity located closer to the equator, in good agreement with tilt angles obtained from 20th century data sets. Sources of uncertainties in the tilt angle determination are discussed and need to be addressed whenever different data sets are combined. Digital images of observations printed in the books Rosa Ursina and Prodromus pro sole mobili by Christoph Scheiner, as well as the drawings from Scheiner’s letters to Marcus Welser, are analyzed to obtain information on the positions and sizes of sunspots that appeared before the Maunder minimum. In most cases, the given orientation of the ecliptic is used to set up the heliographic coordinate system for the drawings. Positions and sizes are measured manually displaying the drawings on a computer screen. Very early drawings have no indication of the solar orientation. A rotational matching using common spots of adjacent days is used in some cases, while in other cases, the assumption that images were aligned with a zenith–horizon coordinate system appeared to be the most likely. In total, 8167 sunspots were measured. A distribution of sunspot latitudes versus time (butterfly diagram) is obtained for Scheiner’s observations. The observations of 1611 are very inaccurate, but the drawings of 1612 have at least an indication of the solar orientation, while the remaining part of the spot positions from 1618–1631 have good to very good accuracy. We also computed 697 tilt angles of apparent bipolar sunspot groups, which were observed in the period 1618–1631. We find that the average tilt angle of nearly 4° does not significantly differ from the 20th century values. The solar cycle properties seem to be related to the tilt angles of sunspot groups, and it is an important parameter in the surface flux transport models. The tilt angles of bipolar sunspot groups from various historical sets of solar drawings including from Schwabe and Scheiner are analyzed. Data by Scheiner, Hevelius, Staudacher, Zucconi, Schwabe, and Spörer deliver a series of average tilt angles spanning a period of 270 years, in addition to previously found values for 20th-century data obtained by other authors. We find that the average tilt angles before the Maunder minimum were not significantly different from modern values. However, the average tilt angles of a period 50 years after the Maunder minimum, namely for cycles 0 and 1, were much lower and near zero. The typical tilt angles before the Maunder minimum suggest that abnormally low tilt angles were not responsible for driving the solar cycle into a grand minimum. With the Schwabe (1826–1867) and Spörer (1866–1880) sunspot data, the butterfly diagram of sunspot groups extends back till 1826. A recently developed method, which separates the wings of the butterfly diagram based on the long gaps present in sunspot group occurrences at different latitudinal bands, is used to separate the wings of the butterfly diagram. The cycle-to-cycle variation in the start (F), end (L), and highest (H) latitudes of the wings with respect to the strength of the wings are analyzed. On the whole, the wings of the stronger cycles tend to start at higher latitudes and have a greater extent. The time spans of the wings and the time difference between the wings in the northern hemisphere display a quasi-periodicity of 5–6 cycles. The average wing overlap is zero in the southern hemisphere, whereas it is 2–3 months in the north. A marginally significant oscillation of about 10 solar cycles is found in the asymmetry of the L latitudes. This latest, extended database of butterfly wings provides new observational constraints, regarding the spatio-temporal distribution of sunspot occurrences over the solar cycle, to solar dynamo models. N2 - Die Sonnenaktivität und ihre Folgen beeinflussen das Weltraumwetter und das Klima. Sie zeigt ein zyklisches Verhalten mit einer Periode von etwa 11 Jahren. Die Eigenschaften des Sonnenzyklus werden durch den magnetischen Dynamo bestimmt, der im Innern der Sonne Wärmeenergie über Bewegungsenergie in magnetische Energie umwandelt. Unser Wissen über den Sonnenzyklus in der Vergangenheit zu verbessern ist wichtig für das Verständnis des Sonnendynamos und die Vorhersage des Weltraumwetters. Durch die Auswertung historischer Sonnenfleckenzeichnungen können wir diese Kenntnisse erweitern. Sonnenflecken sind die dunklen Bereiche auf der Sonnenoberfläche, die mit starken Magnetfeldern verbunden sind. Sonnenflecken sind das am längsten beobachtete Phänomen der Sonnenaktivität. Eine der umfangreichsten Beobachtungsreihen von Sonnenflecken ist die Sammlung von Samuel Heinrich Schwabe aus den Jahren 1825–1867. Die in den Zeichnungen eingetragenen Sonnenflecken sind jedoch nicht maßstäblich. In der vorliegenden Arbeit wurde ein Verfahren entwickelt, mit dem die Fleckendaten des 19. Jahrhunderts unter der Annahme rekonstruiert werden können, dass deren Größnverteilung identisch zu der heutigen ist. Insgesamt konnten wir Positionen und Flächen von etwa 130 000 Sonnenflecken aus Schwabes Archiv bestimmen. Die Jahresmittel der Flächen korrelieren gut mit der so genannten Sonnenfleckenrelativzahl, einer Größe, die aus der Anzahl der Fleckengruppen und der Gesamtzahl der Flecken konstruiert wird und üblicherweise als Standardmaß für die Sonnenaktivität verwendet wird. Fleckengruppen sind zumeist bipolar mit einer magnetisch positiven und einer magnetisch negativen Teilgruppe. Der Neigungswinkel dieser Gruppen gegen den Sonnenäquator wurde ebenfalls bestimmt. Ihr Mittelwert von 5.85° ± 0.25° stimmt gut mit Werten aus dem 20. Jahrhundert überein. Zusätzlich wurden Digitalsierte Beobachtungen von Christoph Scheiner aus dem 17. Jahrhundert analysiert, um Informationen über die Zeit vor dem Maunder-Minimum, einer Periode äußerst geringer Sonnenaktivität, zu erlangen. Bei den frühesten Beobachtungen gibt es keinen Hinweis auf die Ausrichtung des Sonnenbildes. Durch die Nutzung der Sonnenrotation über zwei oder mehr Tage können wir jedoch die Ausrichtungen fixieren. Insgesamt wurden 8167 Sonnenflecken vermessen. Darüberhinaus wurden auch 697 Neigungswinkel von bipolaren Gruppen aus den Jahren 1618–1631 berechnet. Der durchschnittliche Neigungswinkel von fast 4° unterscheidet sich nicht signifikant von den Werten im 20. Jahrhundert. Die Neigungswinkel der Sonnenfleckengruppen scheinen Einfluss auf den Dynamo zu haben. Es wurden in der vorliegenden Arbeit noch weitere Neigungen bipolarer Sonnenfleckengruppen aus verschiedenen historischen Beobachtungsreihen aus 270 Jahren bestimmt, insgesamt von den Beobachtern Scheiner, Hevelius, Staudacher, Zucconi, Schwabe und Spörer. Die durchschnittlichen Neigungswinkel vor dem Maunder-Minimum unterschieden sich nicht wesentlich von modernen Werten, außer etwa 50 Jahren nach dem Maunder-Minimum, als die mittlere Neigung nahe Null war. Da die typischen Neigungswinkel vor dem Maunder-Minimum sich jedoch nicht wesentlich von modernen Werten unterscheiden, legt dies nahe, dass die ungewöhnlich niedrige Werte nicht für das Eintreten der Sonne in eine solche Minimums-Periode verantwortlich waren. Mit den Sonnenfleckendaten von Schwabe (1826–1867) und Spörer (1866–1880) reicht das so genannte Schmetterlingsdiagramm von Sonnenfleckengruppen bis 1826 zurück. Eine kürzlich entwickelte Methode, die Nord- und Südhälften des Schmetterlingsdiagramms zu trennen, zeigte Zyklus-zu-Zyklus-Variationen in der Start-, End-, und höchsten Breite der Teilflächen. Die “Schmetterlingsflächen” der stärkeren Zyklen tendieren dazu, in höheren Breiten zu starten und eine größere Ausdehnung zu haben. Nord- und Südhemisphäre der Sonne zeigen einen neu beginnenden Zyklus zu leicht unterschiedlichen Zeiten. Der Phasenunterschied schwankt langsam mit einer Quasiperiode von 5–6 Zyklen. Die oben erwähnten Resultate zeigen, wie hilfreich historische langzeit Analysen sind, um die Parameter des Sonnendynamos zu bestimmen und so Rückschlüsse auf die ihm zugrunde liegenden Prozesse ziehen zu können. KW - solar activity KW - sunspot group tilt angle KW - cycle-averaged tilt angle KW - history and philosophy of astronomy KW - Sonnenaktivität KW - Neigungswinkel Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-413600 ER - TY - THES A1 - Steiglechner, Peter T1 - Estimating global warming from anthropogenic heat emissions T1 - Abschätzung der globalen Erwärmung durch anthropogene Abwärme BT - conceptual and numerical modelling approaches BT - konzeptionelle und numerische Modellierungsansätze N2 - The forcing from the anthropogenic heat flux (AHF), i.e. the dissipation of primary energy consumed by the human civilisation, produces a direct climate warming. Today, the globally averaged AHF is negligibly small compared to the indirect forcing from greenhouse gas emissions. Locally or regionally, though, it has a significant impact. Historical observations show a constant exponential growth of worldwide energy production. A continuation of this trend might be fueled or even amplified by the exploration of new carbon-free energy sources like fusion power. In such a scenario, the impacts of the AHF become a relevant factor for anthropogenic post-greenhouse gas climate change on the global scale, as well. This master thesis aims at estimating the climate impacts of such a growing AHF forcing. In the first part of this work, the AHF is built into simple and conceptual, zero- and one-dimensional Energy Balance Models (EBMs), providing quick order of magnitude estimations of the temperature impact. In the one-dimensional EBM, the ice-albedo feedback from enhanced ice melting due to the AHF increases the temperature impact significantly compared to the zero-dimensional EBM. Additionally, the forcing is built into a climate model of intermediate complexity, CLIMBER-3α. This allows for the investigation of the effect of localised AHF and gives further insights into the impact of the AHF on processes like the ocean heat uptake, sea ice and snow pattern changes and the ocean circulation. The global mean temperature response from the AHF today is of the order of 0.010 − 0.016 K in all reasonable model configurations tested. A transient tenfold increase of this forcing heats up the Earth System additionally by roughly 0.1 − 0.2 K in the presented models. Further growth can also affect the tipping probability of certain climate elements. Most renewable energy sources do not or only partially contribute to the AHF forcing as the energy from these sources dissipates anyway. Hence, the transition to a (carbon-free) renewable energy mix, which, in particular, does not rely on nuclear power, eliminates the local and global climate impacts from the increasing AHF forcing, independent of the growth of energy production. N2 - Das Forcing durch die Emission von anthropogener Abwärme (AHF), d.h. die Dissipation von konsumierter Primärenergie, stellt einen Beitrag zu einer direkten Klimaerwärmung dar. Der global gemittelte AHF ist heutzutage vernachlässigbar klein im Vergleich zu dem indirekten Forcing durch Treibhausgasemissionen. Auf lokaler oder regionaler Ebene hat das Forcing jedoch einen signifikanten Einfluss. Die Energieproduktion hat in der Vergangenheit ein konstant exponentielles Wachstum aufgezeigt. Dieser Trend kann durch die Erschließung neuer CO2-neutraler Energiequellen, wie zum Beispiel Fusionsenergie, weiter bestärkt und angetrieben werden. In solch einem Szenario führt das AHF Forcing zu einem auch global relevanten Beitrag zum menschengemachten Klimawandel abseits der Treibhausgasemissionen. In dieser Arbeit sollen die Auswirkungen eines wachsenden AHF auf das Klima abgeschätzt werden. Im ersten Teil wird das zusätzliche Forcing in einfache und konzeptionelle, null- und eindimensionale Energiebilanzmodelle (EBM) eingebaut. Diese bieten schnelle Größenordnungsabschätzungen des Temperaturanstiegs. Im eindimensionalen EBM erhöht die Eis-Albedo-Rückkopplung die Temperatur signifikant im Verlgeich zum nulldimensionalen Fall aufgrund von verstärkter Eisschmelze. Zusätzlich, wird das AHF Forcing in das Erdsystemmodell mittlerer Komplexität CLIMBER-3α eingebaut. Dieses erlaubt eine Analyse des Effekts eines heterogenen AHF Forcings und gibt weitere Einblicke in die Einflüsse auf Prozessse wie den Wärmefluss in den Ozean, Veränderungen in Meereis und Schneebedeckung und die Ozeanzirkulation. Der global gemittelte Temperaturanstieg für das heutige AHF Forcing beträgt 0.010 − 0.016 K in allen realistischen, getesteten Modellkonfigurationen. Ein transienter Anstieg des Forcings auf den zehnfachen Wert erwärmt die Erde um weitere 0.1 − 0.2 K in den vorgestellten Modellen. Weiteres Wachstum kann zusätzlich auch das Kippen von bestimmten Klimaelementen beeinflussen. Die meisten erneuerbaren Energiequellen tragen nicht oder nur kaum zu der anthropogenen Abwärme bei, da deren Energie sowieso dissipiert. Daher beseitigt ein Wechsel auf einen CO2-neutralen, erneuerbaren Energiemix, der explizit nicht auf nuklearen Brennstoffen basiert, unabhängig von dem Wachstum der Energieproduktion die lokalen wie auch globalen Auswirkungen des AHF Effekts. KW - climate change KW - waste heat KW - heat island KW - energy balance model KW - climate model of intermediate complexity KW - Klimawandel KW - Abwärme KW - Wärmeinsel KW - Energiebilanzmodell KW - Klimamodell mittlerer Komplexität Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-498866 ER - TY - THES A1 - Jovanovic, Nenad T1 - The comprehension of the passive voice by different populations and the effects of structural priming on this process N2 - This thesis investigates the comprehension of the passive voice in three distinct populations. First, the comprehension of passives by adult German speakers was studied, followed by an examination of how German-speaking children comprehend the structure. Finally, bilingual Mandarin-English speakers were tested on their comprehension of the passive voice in English, which is their L2. An integral part of testing the comprehension in all three populations is the use of structural priming. In each of the three distinct parts of the research, structural priming was used for a specific reason. In the study involving adult German speakers, productive and receptive structural priming was directly compared. The goal was to see the effect the two priming modalities have on language comprehension. In the study on German-acquiring children, structural priming was an important tool in answering the question regarding the delayed acquisition of the passive voice. Finally, in the study on the bilingual population, cross-linguistic priming was used to investigate the importance of word order in the priming effect, since Mandarin and English have different word orders in passive voice sentences. N2 - Diese Doktorarbeit untersucht das Verständnis von Passivsätzen in drei spezifischen Populationen. Zunächst wurde das Passivverständnis von erwachsenen deutschen Muttersprachlern erforscht, gefolgt von einer Untersuchung des Verständnisses von Passivsätzen deutschsprachiger Kinder. Schließlich wurden bilinguale Mandarin-Sprecher hinsichtlich ihres Verständnisses von Passivsätzen in der englischen Sprache, welche ihre Zweitsprache darstellt, getestet. Ein wesentlicher Bestandteil der Untersuchung des Sprachverständnisses in allen drei Populationen ist der Gebrauch des Structural Priming. In jedem der drei verschiedenen Teile der Untersuchung gab es spezifische Gründe, die Methode des Structural Priming anzuwenden. So wurden in der Studie mit deutschen erwachsenen Muttersprachlern Productive und Receptive Structural Priming unmittelbar mit einander verglichen. Das Ziel war es, die Wirkung von zwei verschiedenen Priming-Modalitäten auf das Sprachverständnis herauszufinden. In der Studie mit deutschsprachigen Kindern war Structural Priming ein wichtiges Hilfsmittel, um die Frage nach dem verzögerten Erwerb des Passivverständnisses zu beantworten. In der Studie der bilingualen Population schließlich wurde Cross-Linguistik (sprachübergreifendes) Priming genutzt um die Bedeutung des Satzbaus auf den Priming-Effekt zu untersuchen, da Mandarin und Englisch in Passivsätzen einen unterschiedlichen Satzbau verwenden. T2 - Das Verständnis von Passivkonstruktionen in verschiedenen Populationen unter Einfluss von strukturellem Priming KW - priming KW - eye-tracing KW - syntax KW - comprehension KW - cross-linguistic KW - passive voice KW - acquisition KW - children KW - bilingual KW - Erwerb KW - cross-linguistisch KW - Augenblickmessung KW - Passive KW - Priming KW - Syntax KW - Verständnis KW - Kinder KW - bilingual Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-475900 ER - TY - CHAP A1 - Petsche, Hans-Joachim T1 - In honour of Seymour Papert BT - "Empirical Modelling" of Logo in Forth N2 - Forth is nice and flexible but to a philosopher and teacher educator Logo is the more impressing language. Both are relatives of Lisp, but Forth has a reverse Polish notation where as Logo has an infix notation. Logo allows top down programming, Forth only bottom up. Logo enables recursive programming, Forth does not. Logo includes turtle graphics, Forth has nothing comparable. So what to do if you can't get Logo and have no information about its inner architecture? This should be a case of "empirical modelling": How can you model observable results of the behaviour of Logo in terms of Forth? The main steps to solve this problem are shown in the first part of the paper. The second part of the paper discusses the problem of modelling and shows that the modelling of making and the modelling of recognition have the same mathematical structure. So "empirical modelling" can also serve for modelling desired behaviour of technical systems. The last part of the paper will show that the heuristic potential of a problem which should be modeled is more important than the programming language. The Picasso construal shows, in a very simple way, how children of different ages can model emotional relations in human behaviour with a simple Logo system. KW - Papert KW - LOGO KW - FORTH KW - Empirical Modelling KW - Construal Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-497302 ER - TY - GEN A1 - Brzezinka, Krzysztof A1 - Altmann, Simone A1 - Bäurle, Isabel T1 - BRUSHY1/TONSOKU/MGOUN3 is required for heat stress memory T2 - Postprints der Universität Potsdam Mathematisch-Naturwissenschaftliche Reihe N2 - Plants encounter biotic and abiotic stresses many times during their life cycle and this limits their productivity. Moderate heat stress (HS) primes a plant to survive higher temperatures that are lethal in the naive state. Once temperature stress subsides, the memory of the priming event is actively retained for several days preparing the plant to better cope with recurring HS. Recently, chromatin regulation at different levels has been implicated in HS memory. Here, we report that the chromatin protein BRUSHY1 (BRU1)/TONSOKU/MGOUN3 plays a role in the HS memory in Arabidopsis thaliana. BRU1 is also involved in transcriptional gene silencing and DNA damage repair. This corresponds with the functions of its mammalian orthologue TONSOKU-LIKE/NF Kappa BIL2. During HS memory, BRU1 is required to maintain sustained induction of HS memory-associated genes, whereas it is dispensable for the acquisition of thermotolerance. In summary, we report that BRU1 is required for HS memory in A. thaliana, and propose a model where BRU1 mediates the epigenetic inheritance of chromatin states across DNA replication and cell division. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 788 KW - Arabidopsis thaliana KW - BRU1 KW - chromatin KW - priming Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-436219 SN - 1866-8372 IS - 788 ER - TY - JOUR A1 - Ichikawa, Hiroshi T1 - Prospects of Japanese Translation of the Babylonian Talmud JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien [23 (2017)] = JewBus, Jewish Hindus & other Jewish Encounters with East Asian Religions JF - PaRDeS : Journal of the Association of Jewish Studies [23 (2017)] = JewBus, Jewish Hindus & other Jewish Encounters with East Asian Religions N2 - An academic project of translating the Babylonian Talmud into Japanese was initiated by a president of private jewelry company in 1986 and sixteen volumes of it were published with the collaboration of more than ten Japanese scholars of the Bible and Judaism until 2016. In order to make an assessment for possible impacts of this translation on Japanese cultural revitalization, the author tried to perceive the collision and struggles the Talmud has faced in transmitting itself to later generations even to the present days as it has still claimed its universal validity. It will be helpful to envisage Jewish intellectuals of the subsequent generations wondering what it was to live according to the Torah and the Talmud and how they coped with difficulties in facing the collision of foreign cultural impacts especially in the modern era. As the Japanese people had been profoundly influenced by Buddhism before the modern era, the assumption of the similarity between the Buddhist notion of enlightenment through transmission of the ineffable truth and the similar notion of Rabbinic Judaism will help prospect the possible influence of the Jewish scripture. This Buddhist notion had been most successfully developed in the tradition of Zen Buddhism in Japan. Furthermore this notion was fully and more influentially developed in the sphere of education of Japanese military ruling class and their cultural achievements before the modern era. So we suppose that Jewish endeavors in the Talmudic studies facing collisions and struggles against western impacts will give some insights in considering Japanese struggles against, and responses to, the forceful impacts of the modern West upon our traditional value system. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-408982 SN - 978-3-86956-418-0 SN - 1614-6492 SN - 1862-7684 IS - 23 SP - 183 EP - 198 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Sigalow, Emily T1 - From Jewish Prominence to Buddhist Prominence BT - Julius Goldwater and the Jewish-Buddhist Encounter from 1924–1958 JF - PaRDeS : Zeitschrift der Vereinigung für Jüdische Studien [23 (2017)] = JewBus, Jewish Hindus & other Jewish Encounters with East Asian Religions JF - PaRDeS : Journal of the Association of Jewish Studies [23 (2017)] = JewBus, Jewish Hindus & other Jewish Encounters with East Asian Religions N2 - The 1920s witnessed a growing appearance of individual American Jews– largely from wealthy and prominent families – who received training by Asian teachers and pursued Buddhist practices in Asian-founded Buddhist groups. Some of these American Jews gained prominence and leadership status in Buddhist communities and also ran their own semi-established Buddhist groups, with limited success. The social position and material success of these Jewish Buddhists allowed them the time and means to study and practice Buddhism. This paper illustrates these developments through the story of Julius Goldwater, a member of the prominent German Jewish family that included Senator Barry Goldwater. After encountering Buddhism in Hawaii and being ordained in Kyoto, Goldwater moved to Los Angeles to become one of the first European-American Jodo Shinshu ministers in America. This paper demonstrates how he was an early convert, teacher, and wartime proponent of American Buddhism. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-408943 SN - 978-3-86956-418-0 SN - 1614-6492 SN - 1862-7684 IS - 23 SP - 119 EP - 131 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Ette, Ottmar T1 - Languages about Languages BT - Two Brothers and one Humboldtian Science JF - HiN : Alexander von Humboldt im Netz ; International Review for Humboldtian Studies N2 - In the history of Humboldt research both brothers have been traditionally seen as representing the dichotomy between the humanities and the natural sciences. Today however, their similar approach to using and forming scientific language could be used as a starting point for conceiving a university, museum and even forum under one single Humboldtian science. N2 - En la investigación humboldtiana, los hermanos tradicionalmente representaban la oposición entre las humanidades y las ciencias naturales. Hoy, en cambio, su enfoque similar de usar y construir las lenguas y los discursos de sus respectivas disciplinas se puede usar como punto de partida en concebir una universidad, un museo y un fórum desde una sola ciencia humboldtiana. N2 - In der Vergangenheit sah die Humboldt-Forschung beide Brüder als Vertreter gegenteiliger wissenschaftlicher Ansätze. Heute jedoch kann ihr ähnlicher Zugang zu wissenschaftlicher Sprache als Ausgangspunkt für die Konzipierung einer Universität, eines Museums und Forums unter einer einzigen Humboldtschen Wissenschaft genutzt werden. KW - Wilhelm von Humboldt KW - Alexander von Humboldt KW - cooperation KW - Humboldt brothers KW - Humboldtian science KW - world science KW - epistemology of expansion KW - critical convivence KW - convivence of languages KW - multilingualism KW - energeia KW - Weltansicht KW - Totaleindruck KW - multi-logical Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419414 SN - 1617-5239 SN - 2568-3543 VL - XIX IS - 36 SP - 47 EP - 61 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - GEN A1 - Bösel, Bernd T1 - Affect Disposition(ing) BT - A Genealogical Approach to the Organization and Regulation of Emotions T2 - Media and Communication N2 - The “affective turn” has been primarily concerned not with what affect is, but what it does. This article focuses on yet another shift towards how affect gets organized, i.e., how it is produced, classified, and controlled. It proposes a genealogical as well as a critical approach to the organization of affect and distinguishes between several “affect disposition(ing) regimes”—meaning paradigms of how to interpret and manage affects, for e.g., encoding them as byproducts of demonic possession, judging them in reference to a moralistic framework, or subsuming them under an industrial regime. Bernard Stiegler’s concept of psychopower will be engaged at one point and expanded to include social media and affective technologies, especially Affective Computing. Finally, the industrialization and cybernetization of affect will be contrasted with poststructuralist interpretations of affects as events. T3 - Zweitveröffentlichungen der Universität Potsdam : Philosophische Reihe - 151 KW - affect KW - Affective Computing KW - disposition KW - emotions KW - event KW - eventology KW - genealogy KW - psychopower KW - theory Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-418309 SP - 15 EP - 21 ER - TY - GEN A1 - Wetzel, Maria A1 - Kempka, Thomas A1 - Kühn, Michael T1 - Quantifying rock weakening due to decreasing calcite mineral content by numerical simulations T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The quantification of changes in geomechanical properties due to chemical reactions is of paramount importance for geological subsurface utilisation, since mineral dissolution generally reduces rock stiffness. In the present study, the effective elastic moduli of two digital rock samples, the Fontainebleau and Bentheim sandstones, are numerically determined based on micro-CT images. Reduction in rock stiffness due to the dissolution of 10% calcite cement by volume out of the pore network is quantified for three synthetic spatial calcite distributions (coating, partial filling and random) using representative sub-cubes derived from the digital rock samples. Due to the reduced calcite content, bulk and shear moduli decrease by 34% and 38% in maximum, respectively. Total porosity is clearly the dominant parameter, while spatial calcite distribution has a minor impact, except for a randomly chosen cement distribution within the pore network. Moreover, applying an initial stiffness reduced by 47% for the calcite cement results only in a slightly weaker mechanical behaviour. Using the quantitative approach introduced here substantially improves the accuracy of predictions in elastic rock properties compared to general analytical methods, and further enables quantification of uncertainties related to spatial variations in porosity and mineral distribution. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1092 KW - digital rock physics KW - micro-CT KW - elastic properties KW - numerical simulation KW - chemical-mechanical interaction KW - Code_Aster KW - composite properties Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-473089 SN - 1866-8372 IS - 1092 ER - TY - GEN A1 - Martens, Sonja A1 - Juhlin, Christopher A1 - Bruckman, Viktor J. A1 - Mitchell, Kristen A1 - Griffiths, Luke A1 - Kühn, Michael T1 - Editorial: energy, resources and the environment BT - interdisciplinary answers to approach the sustainable energy and resources conundrum T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - Every year, the European Geosciences Union (EGU) brings together experts from all over the world at its General Assembly, covering all disciplines of the Earth, planetary and space sciences. The EGU Division on Energy, Resources and the Environment (ERE) is concerned with one of the humankind's most challenging goals – providing affordable, reliable and sustainable energy and other georesources. A collection of contributions from the ERE Division at the EGU General Assembly 2018 is assembled within the present special issue in Advances in Geosciences. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 834 Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427880 SN - 1866-8372 IS - 834 ER - TY - RPRT A1 - Krieger, Heike A1 - Zimmermann, Andreas T1 - Sentenza 238/2014 of the Italian Constitutional Court and the International Rule of Law T2 - KFG Working Paper Series N2 - The German-Italian dispute over the scope of sovereign immunities and claims of reparations for war crimes committed by German armed forces during World War II in Italy is in many ways specific and historically contingent. At the same time, it touches upon a number of fundamental challenges which the international community has to address in the interest of furthering the international rule of law. In this working paper both authors address the question whether the current law of sovereign immunities should be changed or interpreted in a manner as to allow for exceptions from State immunities in cases of grave violations of human rights. While the first part of the paper focusses on the perspective of general international law the second part addresses the question through the lense of European law. Both authors agree that unilateral efforts to push for what many consider a progressive development of international law actually may entail adverse effects for the international rule of law and thus may even contribute to a broader crisis of the international legal order. T3 - KFG Working Paper Series - 15 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-422140 SN - 2509-3770 SN - 2509-3762 IS - 15 ER - TY - GEN A1 - Olmer, Ruth A1 - Engels, Lena A1 - Usman, Abdulai A1 - Menke, Sandra A1 - Malik, Muhammad Nasir Hayat A1 - Pessler, Frank A1 - Göhring, Gudrun A1 - Bornhorst, Dorothee A1 - Bolten, Svenja A1 - Abdelilah-Seyfried, Salim A1 - Scheper, Thomas A1 - Kempf, Henning A1 - Zweigerdt, Robert A1 - Martin, Ulrich T1 - Differentiation of Human Pluripotent Stem Cells into Functional Endothelial Cells in Scalable Suspension Culture T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Endothelial cells (ECs) are involved in a variety of cellular responses. As multifunctional components of vascular structures, endothelial (progenitor) cells have been utilized in cellular therapies and are required as an important cellular component of engineered tissue constructs and in vitro disease models. Although primary ECs from different sources are readily isolated and expanded, cell quantity and quality in terms of functionality and karyotype stability is limited. ECs derived from human induced pluripotent stem cells (hiPSCs) represent an alternative and potentially superior cell source, but traditional culture approaches and 2D differentiation protocols hardly allow for production of large cell numbers. Aiming at the production of ECs, we have developed a robust approach for efficient endothelial differentiation of hiPSCs in scalable suspension culture. The established protocol results in relevant numbers of ECs for regenerative approaches and industrial applications that show in vitro proliferation capacity and a high degree of chromosomal stability. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1182 KW - virus infection KW - progenitor cells KW - in vitro KW - telomere dysfunction KW - cord blood KW - cardiomyogenic differentiation KW - angiogenesis KW - efficient KW - aberrations KW - expression Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427095 SN - 1866-8372 IS - 5 ER - TY - GEN A1 - Waller, Nicole T1 - Connecting Atlantic and Pacific BT - theorizing the Arctic T2 - Atlantic Studies: Global Currents N2 - This essay sets out to theorize the “new” Arctic Ocean as a pivot from which our standard map of the world is currently being reconceptualized. Drawing on theories from the fields of Atlantic and Pacific studies, I argue that the changing Arctic, characterized by melting ice and increased accessibility, must be understood both as a space of transit that connects Atlantic and Pacific worlds in unprecedented ways, and as an oceanic world and contact zone in its own right. I examine both functions of the Arctic via a reading of the dispute over the Northwest Passage (which emphasizes the Arctic as a space of transit) and the contemporary assessment of new models of sovereignty in the Arctic region (which concentrates on the circumpolar Arctic as an oceanic world). However, both of these debates frequently exclude indigenous positions on the Arctic. By reading Canadian Inuit theories on the Arctic alongside the more prominent debates, I argue for a decolonizing reading of the Arctic inspired by Inuit articulations of the “Inuit Sea.” In such a reading, Inuit conceptions provide crucial interventions into theorizing the Arctic. They also, in turn, contribute to discussions on indigeneity, sovereignty, and archipelagic theory in Atlantic and Pacific studies. T3 - Zweitveröffentlichungen der Universität Potsdam : Philosophische Reihe - 146 KW - Atlantic studies KW - Pacific studies KW - Arctic studies KW - Northwest Passage KW - indigeneity KW - sovereignty KW - archipelagic theory Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412692 ER - TY - GEN A1 - Class, Fabian A1 - Kohler, Ulrich A1 - Krawietz, Marian T1 - The Potsdam Grievance Statistics File BT - new data on quality of life and political participation for the German Democratic Republic 1970–1989 T2 - Historical Methods: A Journal of Quantitative and Interdisciplinary History N2 - The newly collected “Potsdam Grievance Statistics File” (PGSF) holds data on the number and topics of grievances (“Eingaben”) that were addressed to local authorities of the German Democratic Republic (GDR) in the years 1970 to 1989. The PGSF allows quantitative analyses on topics such as participation, quality of life, and value change in the German Democratic Republic. This paper introduces the concepts of the data set and discusses the validity of its contents. T3 - Zweitveröffentlichungen der Universität Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe - 97 KW - Potsdam Grievance Statistics File (PGSF) KW - German Democratic Republic (GDR) KW - Eingaben KW - Participation KW - Quality of Life Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412843 ER - TY - GEN A1 - Taron, Ulrike H. A1 - Lell, Moritz A1 - Barlow, Axel A1 - Paijmans, Johanna L. A. T1 - Testing of Alignment Parameters for Ancient Samples BT - Evaluating and Optimizing Mapping Parameters for Ancient Samples Using the TAPAS Tool T2 - Genes N2 - High-throughput sequence data retrieved from ancient or other degraded samples has led to unprecedented insights into the evolutionary history of many species, but the analysis of such sequences also poses specific computational challenges. The most commonly used approach involves mapping sequence reads to a reference genome. However, this process becomes increasingly challenging with an elevated genetic distance between target and reference or with the presence of contaminant sequences with high sequence similarity to the target species. The evaluation and testing of mapping efficiency and stringency are thus paramount for the reliable identification and analysis of ancient sequences. In this paper, we present ‘TAPAS’, (Testing of Alignment Parameters for Ancient Samples), a computational tool that enables the systematic testing of mapping tools for ancient data by simulating sequence data reflecting the properties of an ancient dataset and performing test runs using the mapping software and parameter settings of interest. We showcase TAPAS by using it to assess and improve mapping strategy for a degraded sample from a banded linsang (Prionodon linsang), for which no closely related reference is currently available. This enables a 1.8-fold increase of the number of mapped reads without sacrificing mapping specificity. The increase of mapped reads effectively reduces the need for additional sequencing, thus making more economical use of time, resources, and sample material. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 415 KW - ancient DNA KW - short-read mapping KW - palaeogenomics KW - alignment sensitivity / specificity Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-409683 ER - TY - THES A1 - Lee, Hui-Chun T1 - Toward ultimate control of polymerization and catalytic property T1 - In Richtung ultimative Kontrolle der Polymerisation und der katalytischen Eigenschaft BT - a combination of metal-organic frameworks and ATRP BT - eine Kombination von Metall-organischen Gerüsten und ATRP N2 - Reversible-deactivation radical polymerization (RDRP) is without any doubt one of the most prevalent and powerful strategies for polymer synthesis, by which well-defined living polymers with targeted molecular weight (MW), low molar dispersity (Ɖ) and diverse morphologies can be prepared in a controlled fashion. Atom transfer radical polymerization (ATRP) as one of the most extensive studied types of RDRP has been particularly emphasized due to the high accessibility to hybrid materials, multifunctional copolymers and diverse end group functionalities via commercially available precursors. However, due to catalyst-induced side reactions and chain-chain coupling termination in bulk environment, synthesis of high MW polymers with uniform chain length (low Ɖ) and highly-preserved chain-end fidelity is usually challenging. Besides, owing to the inherited radical nature, the control of microstructure, namely tacticity control, is another laborious task. Considering the applied catalysts, the utilization of large amounts of non-reusable transition metal ions which lead to cumbersome purification process, product contamination and complicated reaction procedures all delimit the scope ATRP techniques. Metal-organic frameworks (MOFs) are an emerging type of porous materials combing the properties of both organic polymers and inorganic crystals, characterized with well-defined crystalline framework, high specific surface area, tunable porous structure and versatile nanochannel functionalities. These promising properties of MOFs have thoroughly revolutionized academic research and applications in tremendous aspects, including gas processing, sensing, photoluminescence, catalysis and compartmentalized polymerization. Through functionalization, the microenvironment of MOF nanochannel can be precisely devised and tailored with specified functional groups for individual host-guest interactions. Furthermore, properties of high transition metal density, accessible catalytic sites and crystalline particles all indicate MOFs as prominent heterogeneous catalysts which open a new avenue towards unprecedented catalytic performance. Although beneficial properties in catalysis, high agglomeration and poor dispersibility restrain the potential catalytic capacity to certain degree. Due to thriving development of MOF sciences, fundamental polymer science is undergoing a significant transformation, and the advanced polymerization strategy can eventually refine the intrinsic drawbacks of MOF solids reversely. Therefore, in the present thesis, a combination of low-dimensional polymers with crystalline MOFs is demonstrated as a robust and comprehensive approach to gain the bilateral advantages from polymers (flexibility, dispersibility) and MOFs (stability, crystallinity). The utilization of MOFs for in-situ polymerizations and catalytic purposes can be realized to synthesize intriguing polymers in a facile and universal process to expand the applicability of conventional ATRP methodology. On the other hand, through the formation of MOF/polymer composites by surface functionalization, the MOF particles with environment-adjustable dispersibility and high catalytic property can be as-prepared. In the present thesis, an approach via combination of confined porous textures from MOFs and controlled radical polymerization is proposed to advance synthetic polymer chemistry. Zn2(bdc)2(dabco) (Znbdc) and the initiator-functionalized Zn MOFs, ZnBrbdc, are utilized as a reaction environment for in-situ polymerization of various size-dependent methacrylate monomers (i.e. methyl, ethyl, benzyl and isobornyl methacrylate) through (surface-initiated) activators regenerated by electron transfer (ARGET/SI-ARGET) ATRP, resulting in polymers with control over dispersity, end functionalities and tacticity with respect to distinct molecular size. While the functionalized MOFs are applied, due to the strengthened compartmentalization effect, the accommodated polymers with molecular weight up to 392,000 can be achieved. Moreover, a significant improvement in end-group fidelity and stereocontrol can be observed. The results highlight a combination of MOFs and ATRP is a promising and universal methodology to synthesize versatile well-defined polymers with high molecular weight, increment in isotactic trial and the preserved chain-end functionality. More than being a host only, MOFs can act as heterogeneous catalysts for metal-catalyzed polymerizations. A Cu(II)-based MOF, Cu2(bdc)2(dabco), is demonstrated as a heterogeneous, universal catalyst for both thermal or visible light-triggered ARGET ATRP with expanded monomer range. The accessible catalytic metal sites enable the Cu(II) MOF to polymerize various monomers, including benzyl methacrylate (BzMA), styrene, methyl methacrylate (MMA), 2-(dimethylamino)ethyl methacrylate (DMAEMA) in the fashion of ARGET ATRP. Furthermore, due to the robust frameworks, surpassing the conventional homogeneous catalyst, the Cu(II) MOF can tolerate strongly coordinating monomers and polymerize challenging monomers (i.e. 4-vinyl pyridine, 2-vinyl pyridine and isoprene), in a well-controlled fashion. Therefore, a synthetic procedure can be significantly simplified, and catalyst-resulted chelation can be avoided as well. Like other heterogeneous catalysts, the Cu(II) MOF catalytic complexes can be easily collected by centrifugation and recycled for an arbitrary amount of times. The Cu(II) MOF, composed of photostimulable metal sites, is further used to catalyze controlled photopolymerization under visible light and requires no external photoinitiator, dye sensitizer or ligand. A simple light trigger allows the photoreduction of Cu(II) to the active Cu(I) state, enabling controlled polymerization in the form of ARGET ATRP. More than polymerization application, the synergic effect between MOF frameworks and incorporated nucleophilic monomers/molecules is also observed, where the formation of associating complexes is able to adjust the photochemical and electrochemical properties of the Cu(II) MOF, altering the band gap and light harvesting behavior. Owing to the tunable photoabsorption property resulting from the coordinating guests, photoinduced Reversible-deactivation radical polymerization (PRDRP) can be achieved to further simplify and fasten the polymerization. More than the adjustable photoabsorption ability, the synergistic strategy via a combination of controlled/living polymerization technique and crystalline MOFs can be again evidenced as demonstrated in the MOF-based heterogeneous catalysts with enhanced dispersibility in solution. Through introducing hollow pollen pivots with surface immobilized environment-responsive polymer, PDMAEMA, highly dispersed MOF nanocrystals can be prepared after associating on polymer brushes via the intrinsic amine functionality in each DMAEMA monomer. Intriguingly, the pollen-PDMAEMA composite can serve as a “smart” anchor to trap nanoMOF particles with improved dispersibility, and thus to significantly enhance liquid-phase photocatalytic performance. Furthermore, the catalytic activity can be switched on and off via stimulable coil-to-globule transition of the PDMAEMA chains exposing or burying MOF catalytic sites, respectively. N2 - Die sogenannte „Reversible-Deactivation Radical Polymerization (RDRP)“ ist eine der am häufigsten genutzten und leistungsstärksten Methoden für die Polymersynthese, mit Hilfe derer genau definierte Polymere mit gezieltem Molekulargewicht (MW), niedriger molarer Dispersität (Ɖ) und verschiedenen Morphologien hergestellt werden können. Die sogenannte „Atom Transfer Radical Polymerization (ATRP) ist eine der am intensivsten untersuchten RDRP Methoden, da sie eine hohe Zugänglichkeit zu Hybridmaterialien, multifunktionellen Copolymeren und diversen Endgruppenfunktionalitäten ermöglicht. Jedoch ist die Synthese von Polymeren mit hohem Molekulargewicht, niedriger Dispersität, exakten Endgruppen und der Steuerung der Taktizität für gewöhnlich schwierig. Außerdem führt die Verwendung von großen Mengen an nichtwiederverwendbaren Übergangsmetallionen zu einem umständlichen Reinigungsprozess, wobei Produktverunreinigungen und komplizierte Reaktionsverfahren die Anwendungsbereiche der ATRP Techniken weiter begrenzen. “Metal-organic frameworks (MOFs)“ sind eine vielversprechende Art von porösen Materialien, die die Eigenschaften von organischen Polymeren und anorganischen Kristallen in sich vereinen und sich durch ein kristallines Gerüst, hohe spezifische Oberflächen, einstellbare poröse Strukturen und vielseitige Nanokanal-Funktionalitäten auszeichnen. Diese vielversprechenden Eigenschaften von MOFs haben die akademische Forschung und ihre Anwendung vielseitig revolutioniert, einschließlich der Photolumineszenz, Katalyse und kompartimentierter Polymerisation. Durch gezielte Funktionalisierung kann die Mikroumgebung von MOF-Nanokanälen mit spezifischen funktionellen Gruppen für individuelle Schlüssel-Schloss-Wechselwirkungen präzise entworfen und maßgeschneidert werden. Darüber hinaus weist die hohe Übergangsmetalldichte, zugängliche katalytische Zentren und die kristallinen Partikel auf MOFs als herausragende heterogene Katalysatoren hin, welche eine vielversprechende Möglichkeit für zukünftige Anwendungen erlauben. Ungeachtet der vorteilhaften Eigenschaften in der Katalyse halten eine hohe Agglomerationstendenz und die schlechte Dispergierbarkeit die potentiellen katalytischen Vorteile bis zu einem gewissen Grad zurück. In der vorliegenden Arbeit wurde eine Kombination von niederdimensionalen Polymeren mit kristallinen MOFs als robuster und umfassender Ansatz zur Erzielung der bilateralen Vorteile von Polymeren (Flexibilität, Dispergierbarkeit) und MOFs (Stabilität, Kristallinität) gezeigt. Die Verwendung von MOFs für in-situ-Polymerisationen und katalytische Zwecke kann realisiert werden, um verblüffende Polymere in einem einfachen und universellen Prozess zu synthetisieren, um die Anwendbarkeit herkömmlicher ATRP Methoden zu erweitern. MOFs können nicht nur als Gerüst dienen, sondern auch selbst als heterogene Katalysatoren für metall-katalysierte Polymerisationen, bedingt durch thermische Behandlung oder sichtbares Licht, fungieren. Auf der anderen Seite können MOF / Polymer-Komposite durch Oberflächenfunktionalisierung hergestellt werden, welche sich schließlich durch einstellbare Dispergierbarkeit und guter katalytischer Eigenschaften auszeichnen. KW - metal organic framework KW - controlled polymerization KW - environmental response KW - liquid-phase catalysis KW - confined polymerization KW - ATRP KW - visible light photocatalysis KW - metallorganischen Gerüstverbindungen KW - kontrollierte Polymerisation KW - Umweltreaktion KW - Flüssigphasenkatalyse KW - begrenzte Polymerisation KW - ATRP KW - sichtbares Licht Photokatalyse Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-414973 ER - TY - THES A1 - Lama, Sandy M. G. T1 - Functionalization of Porous Carbon Materials with Heteroatoms and Application as Supports in Industrial Heterogeneous Catalysis T1 - Funktionalisierung von porösen Kohlenstoffmaterialien mit Heteroatomen und Anwendung als Träger in der industriellen heterogenen Katalyse N2 - Due to a challenging population growth and environmental changes, a need for new routes to provide required chemicals for human necessities arises. An effective solution discussed in this thesis is industrial heterogeneous catalysis. The development of an advanced industrial heterogeneous catalyst is investigated herein by considering porous carbon nano-material as supports and modifying their surface chemistry structure with heteroatoms. Such modifications showed a significant influence on the performance of the catalyst and provided a deeper insight regarding the interaction between the surface structure of the catalyst and the surrounding phase. This thesis contributes to the few present studies about heteroatoms effect on the catalyst performance and emphasizes on the importance of understanding surface structure functionalization in a catalyst in different phases (liquid and gaseous) and for different reactions (hydrogenolysis, oxidation, and hydrogenation/ polymerization). Herein, the heteroatoms utilized for the modifications are hydrogen (H), oxygen (O), and nitrogen (N). The heteroatoms effect on the metal particle size, on the polarity of the support/ the catalyst, on the catalytic performance (activity, selectivity, and stability), and on the interaction with the surrounding phase has been explored. First hierarchical porous carbon nanomaterials functionalized with heteroatoms (N) is synthesized and applied as supports for nickel nanoparticles for hydrogenolysis process of kraft lignin in liquid phase. This reaction has been performed in batch and flow reactors for three different catalysts, two of comparable hierarchical porosity, yet one is modified with N and the other is not, and a third is a prepared catalyst from a commercial carbon support. The reaction production and analyses show that the catalysts with hierarchical porosity perform catalytically much better than in presence of a commercial carbon support with lower surface area. Moreover, the modification with N-heteroatoms enhanced the catalytic performance because the heteroatom modified porous carbon material with nickel nanoparticles catalyst (Ni-NDC) performed highest among the other catalysts. In the flow reactor, Ni-NDC selectively degraded the ether bonds (β-O-4) in kraft lignin with an activity of 2.2 x10^-4 mg lignin mg Ni-1 s-1 for 50 h at 350°C and 3.5 mL min-1 flow, providing ~99 % conversion to shorter chained chemicals (mainly guaiacol derivatives). Then, the functionalization of carbon surface was further studied in selective oxidation of glucose to gluconic acid using < 1 wt. % of gold (Au) deposited on the previously-mentioned synthesized carbon (C) supports with different functionalities (Au-CGlucose, Au-CGlucose-H, Au-CGlucose-O, Au-CGlucoseamine). Except for Au-CGlucose-O, the other catalysts achieved full glucose conversion within 40-120 min and 100% selectivity towards gluconic acid with a maximum activity of 1.5 molGlucose molAu-1 s-1 in an aqueous phase at 45 °C and pH 9. Each heteroatom influenced the polarity of the carbon differently, affecting by that the deposition of Au on the support and thus the activity of the catalyst and its selectivity. The heteroatom effect was further investigated in a gas phase. The Fischer-Tropsch reaction was applied to convert synthetic gas (CO and H2) to short olefins and paraffins using surface-functionalized carbon nanotubes (CNTs) with heteroatoms as supports for ion (Fe) deposition in presence and absence of promoters (Na and S). The results showed the promoted Fe-CNT doped with nitrogen catalyst to be stable up to 180 h and selective to the formation of olefins (~ 47 %) and paraffins (~6 %) with a conversion of CO ~ 92 % at a maximum activity of 94 *10^-5 mol CO g Fe-1 s-1. The more information given regarding this topic can open wide range of applications not only in catalysis, but in other approaches as well. In conclusion, incorporation of heteroatoms can be the next approach for an advanced industrial heterogeneous catalyst, but also for other applications (e.g. electrocatalysis, gas adsorption, or supercapacitors). N2 - Herausforderungen wie Bevölkerungszuwachs und Umweltveränderungen erfordern neue Wege, chemische Substanzen zu erzeugen, um menschliche Anforderungen zu befriedigen. Eine mögliche effektive Lösung dafür, welche in dieser Arbeit diskutiert wird ist die industrielle heterogene Katalyse. Es werden unter dem Einsatz poröser Kohlenstoffträger neue industrielle Katalysatoren untersucht und entwickelt wobei die Oberflächenstruktur dieser Trägermaterialien mit Heteroatomen modifiziert wird. Diese Modifikationen zeigten einen signifikanten Einfluss auf die Eigenschaften der Katalysatoren und erlaubten Rückschlüsse hinsichtlich der Interaktion zwischen Katalysatoroberfläche und umgebender Phase. Die vorliegende Arbeit trägt zu einigen wenigen existierenden Studien bei die sich mit den Einflüssen solcher Heteroatome auf Katalysatoren beschäftigen. Es wird versucht, die Wichtigkeit dieser Oberflächeneigenschaften in Reaktionen (Hydrogenolyse, Oxidation, Hydrierung/ Polymerisation) in verschiedenen Phasen (flüssig oder gasförmig) zu verstehen. Die für die Modifikationen eingesetzten Heteroatome sind Wasserstoff (H), Sauerstoff (O) und Stickstoff (N). Ihr Effekt auf die Größe der Metallpartikel, die Polarität der Träger bzw. Katalysatoren, die eigentlichen katalytischen Eigenschaften und die Interaktion mit der umgebenden Phase wurde untersucht. Zuerst wurden hierarchisch poröse Kohlenstoffmaterialien hergestellt, die mit Stickstoff als Heteroatome funktionalisiert wurden. Diese wurden als Trägermaterialien für Nickel-Nanopartikel in der Hydrogenolyse von Kraft Lignin in flüssiger Phase eingesetzt. Diese Reaktion wurde mit drei unterschiedlichen Katalysatoren in Batch- und Flussreaktoren durchgeführt. Zwei der Katalysatoren hatten vergleichbare hierarchische Porosität. Einer davon war mit Heteroatomen funktionalisiert, einer dagegen nicht. Ein dritter Katalysator wurde mit einem kommerziell erhältlichen Kohlenstoffmaterial hergestellt. Die Reaktion zeigte, dass die Katalysatoren mit hierarchischer Porosität deutlich bessere Eigenschaften zeigen als das kommerzielle Trägermaterial mit geringerer Oberfläche. Darüber hinaus zeigte sich, dass die Modifizierung mit Stickstoffatomen die katalytischen Eigenschaften verbessert, da das modifizierte Kohlenstoffmaterial mit den Nickelpartikeln (Ni-NDC) die besten Ergebnisse aller untersuchten Katalysatoren zeigte. Im Durchflussreaktor wurden von Ni-NDC die Etherbindungen des Kraft Lignins (β-O-4) selektiv mit einer Aktivität von 2.2 x10^-4 mg lignin mg Ni-1 s-1 für 50 h bei 99% Umsatz zu kurzkettigeren Strukturen (hauptsächlich Guajakol-Derivat) gespalten. Außerdem wurde der Einfluss der Funktionalisierung der Kohlenstoffoberfläche in der selektiven Oxidation von Glucose zu Gluconsäure mit 1 Gew.% Gold (Au) auf den vorher angesprochenen Kohlenstoffträgermaterialien mit unterschiedlichen Oberflächenfunktionalitäten (Au-CGlucose, Au-CGlucose-H, Au-CGlucose-O, Au-CGlucoseamine) untersucht. Mit Ausnahme von Au-CGlucose-O erreichten alle Katalysatoren innerhalb von 40-120 min 100% Glucose Umsatz bei 100%iger Selektivität zu Gluconsäure und einer maximalen katalytischen Aktivität von 1.5 molGlucose molAu-1 s-1 in wässriger Phase bei 45°C und pH 9. Die unterschiedlichen Heteroatome wirkten sich unterschiedlich auf die Polarität der Kohlenstoffe und damit auch auf die Abscheidung der Goldpartikel auf die Trägermaterialien und die Katalysatoraktivität und -selektivität aus. Der Einfluss der Heteroatome wurde außerdem in einer Gasphasenreaktion untersucht. Die Fischer-Tropsch Reaktion kam zum Einsatz um Synthesegas (CO und H2) mit Hilfe von Katalysatoren bestehend aus Eisen (Fe) auf Heteroatomfunktionalisierten Kohlenstoffnanoröhrchen (engl. Carbon nanotubes, CNTs) in Gegenwart und Abwesenheit von Promotoren (Na und S) zu kurzkettigen Olefinen und Paraffinen umzuwandeln. Die Ergebnisse zeigten dass die Fe-CNT Katalysatoren mit Promotoren und stickstoffdotierten Trägern bis zu 180 h stabil waren und Olefine (~ 47 %) sowie Paraffine (~6 %) mit guten Selektivitäten bei einem CO Umsatz von 92% und einer maximalen Aktivität von 94 *10^-5 mol CO gFe-1 s-1 hergestellt werden konnten. Je mehr Informationen zu diesem Thema zur Verfügung gestellt werden, kann dies zu einer großen Bandbreite von Anwendungen nicht nur in der Katalyse, sondern auch in anderen Ansätzen beitragen. Zusammenfassend kann der Einbau von Heteroatomen der nächste Ansatz für einen fortgeschrittenen industriellen heterogenen Katalysator sein, aber auch für andere Anwendungen (z.B. Elektrokatalyse, Gasadsorption oder Superkondensatoren). KW - catalysis KW - carbon material KW - carbon supports KW - glucose oxidation KW - Kraft lignin hydrogenolysis KW - Fischer-Tropsch Synthesis KW - Syngas Hydrogenation KW - gold-carbon catalysts KW - nickel-carbon catalysts KW - iron-carbon nanotube catalysts KW - hierarchical porosity KW - heteroatom modification KW - catalyst functionalization KW - Katalyse KW - Kohlenstoffmaterial KW - Kohlenstoffträger KW - Glukoseoxidation KW - Kraftlignin KW - Hydrogenolyse KW - Fischer-Tropsch-Synthese KW - Syngashydrierung KW - Gold-Kohlenstoff-Katalysatoren KW - Nickel-Kohlenstoff-Katalysatoren KW - Eisen-Kohlenstoff-Nanoröhrchen-Katalysatoren KW - hierarchische Porosität KW - Heteroatom-Modifikation KW - Funktionalisierung von Katalysatoren Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-415797 ER - TY - THES A1 - Chaleawlert-Umpon, Saowaluk T1 - Sustainable electrode materials based on lignin T1 - Ligninbasierte nachhaltige Elektrodenmaterialien N2 - The utilization of lignin as renewable electrode material for electrochemical energy storage is a sustainable approach for future batteries and supercapacitors. The composite electrode was fabricated from Kraft lignin and conductive carbon and the charge storage contribution was determined in terms of electrical double layer (EDL) and redox reactions. The important factors at play for achieving high faradaic charge storage capacity contribute to high surface area, accessibility of redox sites in lignin and their interaction with conductive additives. A thinner layer of lignin covering the high surface area of carbon facilitates the electron transfer process with a shorter pathway from the active sites of nonconductive lignin to the current collector leading to the improvement of faradaic charge storage capacity. Composite electrodes from lignin and carbon would be even more sustainable if the fluorinated binder can be omitted. A new route to fabricate a binder-free composite electrode from Kraft lignin and high surface area carbon has been proposed by crosslinking lignin with glyoxal. A high molecular weight of lignin is obtained to enhance both electroactivity and binder capability in composite electrodes. The order of the processing step of crosslinking lignin on the composite electrode plays a crucial role in achieving a stable electrode and high charge storage capacity. The crosslinked lignin based electrodes are promising since they allow for more stable, sustainable, halogen-free and environmentally benign devices for energy storage applications. Furthermore, improvement of the amount of redox active groups (quinone groups) in lignin is useful to enhance the capacity in lithium battery applications. Direct oxidative demethylation by cerium ammonium nitrate has been carried out under mild conditions. This proves that an increase of quinone groups is able to enhance the performance of lithium battery. Thus, lignin is a promising material and could be a good candidate for application in sustainable energy storage devices. N2 - Die Verwendung von Lignin als erneuerbares Ausgangsmaterial für Elektroden ist ein nachhaltiger Ansatz für die Herstellung der nächsten Generation von Batterien und Superkondensatoren. In dieser Arbeit werden Verbundelektroden auf der Basis von Kraft-Lignin und leitfähigem Kohlenstoff hergestellt und getestet. Die Beiträge des Aufbaus einer elektrischen Doppelschicht (EDL) und der Redoxreaktionen zur Kapazität der Elektrode werden diskutiert. Die wichtigsten Faktoren um eine hohe faradaysche Kapazität der aktiven Gruppen in Lignin zu erreichen sind eine große Oberfläche, die Zugänglichkeit der redoxaktiven Gruppen, sowie die Wechselwirkung mit leitfähigen Additiven. Dabei verringert eine dünnere Ligninschicht auf der Oberfläche des leitfähigen Kohlenstoffs den Elektronentransportweg zwischen den redoxaktiven Gruppen und dem Stromabnehmer und wirkt sich somit positiv auf die faradaysche Kapazität aus. Traditionelle Verbundelektroden enthalten in der Regel fluorierte Bindemittel, was deren Nachhaltigkeit in Frage stellt. Die Verwendung von Glyoxal als Quervernetzer für Lignin stellt eine Alternative zur Herstellung von bindemittelfreien ligninbasierten Verbundelektroden dar. Durch die Quervernetzung wird Lignin mit hohem Molekulargewicht erhalten, was sich insbesondere vorteilhaft auf die Stabilität der Elektroden auswirkt. Für das Erreichen einer hohen Kapazität spielt allerdings die Reihenfolge der Produktionsschritte eine entscheidende Rolle, was hier auch diskutiert wird. Eine Erhöhung der Anzahl an redoxativen Gruppen, insbesondere Chinon-Funktionalitäten, im Lignin führt darüber hinaus zur Erhöhung der Kapazität in primären Lithiumbatterien. Die direkte oxidative Demethylierung von Phenylethern mit Hilfe von Cerammoniumnitrat wurde in dieser Arbeit unter milden Reaktionsbedingungen durchgeführt und die verbesserte Kapazität in Lithiumbatterien aufgrund der erhöhten Anzahl an redoxaktiven Gruppen aufgezeigt. Abschließend kann Lignin, quervernetzt oder oxidiert, als vielversprechender Wegbereiter für nachhaltige Materialen in der Energiespeicherung angesehen werden. KW - lignin KW - energy storage KW - sustainable energy storage materials KW - Lignin KW - Energiespeicher KW - nachhaltige Energiespeichermaterialien Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-411793 ER - TY - THES A1 - Li, Lina T1 - Preparation of novel photoactive materials T1 - Herstellung von neuen photoaktiven Materialien BT - different pre-compositions, post-modifications and improved performance BT - verschiedene Vorzusammensetzungen, Post-Modifikationen und verbesserte Leistung N2 - Photocatalysis is considered significant in this new energy era, because the inexhaustibly abundant, clean, and safe energy of the sun can be harnessed for sustainable, nonhazardous, and economically development of our society. In the research of photocatalysis, the current focus was held by the design and modification of photocatalyst. As one of the most promising photocatalysts, g-C3N4 has gained considerable attention for its eye-catching properties. It has been extensively explored in photocatalysis applications, such as water splitting, organic pollutant degradation, and CO2 reduction. Even so, it also has its own drawbacks which inhibit its further application. Inspired by that, this thesis will mainly present and discuss the process and achievement on the preparation of some novel photocatalysts and their photocatalysis performance. These materials were all synthesized via the alteration of classic g-C3N4 preparation method, like using different pre-compositions for initial supramolecular complex and functional group post-modification. By taking place of cyanuric acid, 2,5-Dihydroxy-1,4-benzoquinone and chloranilic acid can form completely new supramolecular complex with melamine. After heating, the resulting products of the two complex shown 2D sheet-like and 1D fiber-like morphologies, respectively, which maintain at even up to high temperature of 800 °C. These materials cover crystals, polymers and N-doped carbons with the increase of synthesis temperature. Based on their different pre-compositions, they show different dye degradation performances. For CLA-M-250, it shows the highest photocatalytic activity and strong oxidation capacity. It shows not only great photo-performance in RhB degradation, but also oxygen production in water splitting. In the post-modification method, a novel photocatalysis solution was proposed to modify carbon nitride scaffold with cyano group, whose content can be well controlled by the input of sodium thiocyanate. The cyanation modification leads to narrowed band gap as well as improved photo-induced charges separation. Cyano group grafted carbon nitride thus shows dramatically enhanced performance in the photocatalytic coupling reaction between styrene and sodium benzenesulfinate under green light irradiation, which is in stark contrast with the inactivity of pristine g-C3N4. N2 - Die Sonne stellt eine Quelle für unerschöpfliche, saubere und sichere Energie dar, die für eine nachhaltige, ungefährliche und ökonomische Entwicklung unserer Gesellschaft genutzt werden kann, daher wird Photokatalyse heutzutage als äußerst vielversprechend angesehen. Bei der Erforschung der Photokatalyse lag der Fokus auf dem Design und der Modifizierung von Photokatalysatoren. Als einer der vielversprechendsten Photokatalysatoren hat sich g-C3N4 erwiesen. Es wurde ausführlich für Anwendungen wie z.B. Wasserspaltung, den Abbau organischer Schadstoffe und CO2-Reduktion untersucht. Trotzdem hat es auch Nachteile, die eine weitere Anwendung erschweren. Deshalb wird in dieser Arbeit hauptsächlich die Herstellung und Eigenschaften von neuartigen auf auf g-C3N4 basierenden Photokatalysatoren vorgestellt und diskutiert. Diese Materialien wurden mittels Verfahren hergestellt, bei denen die klassische g-C3N4-Herstellungsmethode geändert wurde, wie z.B. durch die Verwendung unterschiedlicher Zusammensetzungen und durch die Modifizierung von funktionellen Gruppen. Im Vergleich zu g-C3N4 weisen diese neu hergestellten Materialien unterschiedliche photokatalytische Eigenschaften auf. KW - photocatalysis KW - Photokatalyse KW - CN materials KW - CN-Materialien KW - supramolecular KW - Supramolekular KW - post-modification KW - Post-Modifikationen Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-410952 ER - TY - GEN A1 - Martin-Creuzburg, Dominik A1 - Massier, Tamara A1 - Wacker, Alexander T1 - Sex-specific differences in essential lipid requirements of Daphnia magna T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Sex-specific differences in nutritional requirements may crucially influence the performances of the sexes, which may have implications for sexual reproduction and thus is of great ecological and evolutionary interest. In the freshwater model species Daphnia magna, essential lipid requirements have been extensively studied. Dietary deficiencies in sterols and polyunsaturated fatty acids (PUFA) have been shown to constrain somatic growth and parthenogenetic reproduction of female Daphnia. In contrast, nutrient requirements of male Daphnia have not been studied yet. Supplementation experiments were conducted to investigate differences in sterol (cholesterol) and PUFA (eicosapentaenoic acid, EPA) requirements between female and male D. magna. Thresholds for sterol-limited juvenile growth were higher in females than in males, suggesting that females are more susceptible to dietary sterol deficiencies than males. Sex-specific differences in maximum somatic growth rates were evident primarily in the presence of dietary EPA; females could not exploit their generally higher growth potential in the absence of dietary PUFA. However, the thresholds for EPA-limited growth did not differ between sexes, suggesting that both sexes have similar dietary EPA requirements during juvenile growth. During a life history experiment, the gain in body dry mass was higher in females than in males, irrespective of food treatment. In both sexes, the gain in body dry mass increased significantly upon EPA supplementation, indicating that both sexes benefited from dietary EPA supply also later in life. However, the positive effects of EPA supplementation were most pronounced for female reproduction-related traits (i.e., clutch sizes, egg dry masses, and total dry mass investment in reproduction). The high maternal investment in reproduction resulted in a depletion of nutrients in female somata. In contrast, the comparatively low paternal investment in reproduction allowed for the accumulation of nutrients in male somata. We conclude that males are generally less susceptible to dietary nutrient deficiencies than females, because they can rely more on internal body stores. Our data suggest that the performances of the sexes are differentially influenced by lipid-mediated food quality, which may have consequences for sexual reproduction and thus the production of resting eggs and the maintenance of Daphnia populations. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1050 KW - allocation KW - cholesterol KW - eicosapentaenoic acid KW - food quality KW - male Daphnia KW - polyunsaturated fatty acids KW - sterols KW - lipid limitation thresholds Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-469099 SN - 1866-8372 IS - 1050 ER - TY - THES A1 - Kruse, Sebastian T1 - Scalable data profiling T1 - Skalierbares Data Profiling BT - distributed discovery and analysis of structural metadata BT - Entdecken und Analysieren struktureller Metadaten N2 - Data profiling is the act of extracting structural metadata from datasets. Structural metadata, such as data dependencies and statistics, can support data management operations, such as data integration and data cleaning. Data management often is the most time-consuming activity in any data-related project. Its support is extremely valuable in our data-driven world, so that more time can be spent on the actual utilization of the data, e. g., building analytical models. In most scenarios, however, structural metadata is not given and must be extracted first. Therefore, efficient data profiling methods are highly desirable. Data profiling is a computationally expensive problem; in fact, most dependency discovery problems entail search spaces that grow exponentially in the number of attributes. To this end, this thesis introduces novel discovery algorithms for various types of data dependencies – namely inclusion dependencies, conditional inclusion dependencies, partial functional dependencies, and partial unique column combinations – that considerably improve over state-of-the-art algorithms in terms of efficiency and that scale to datasets that cannot be processed by existing algorithms. The key to those improvements are not only algorithmic innovations, such as novel pruning rules or traversal strategies, but also algorithm designs tailored for distributed execution. While distributed data profiling has been mostly neglected by previous works, it is a logical consequence on the face of recent hardware trends and the computational hardness of dependency discovery. To demonstrate the utility of data profiling for data management, this thesis furthermore presents Metacrate, a database for structural metadata. Its salient features are its flexible data model, the capability to integrate various kinds of structural metadata, and its rich metadata analytics library. We show how to perform a data anamnesis of unknown, complex datasets based on this technology. In particular, we describe in detail how to reconstruct the schemata and assess their quality as part of the data anamnesis. The data profiling algorithms and Metacrate have been carefully implemented, integrated with the Metanome data profiling tool, and are available as free software. In that way, we intend to allow for easy repeatability of our research results and also provide them for actual usage in real-world data-related projects. N2 - Data Profiling bezeichnet das Extrahieren struktureller Metadaten aus Datensätzen. Stukturelle Metadaten, z.B. Datenabhängigkeiten und Statistiken, können bei der Datenverwaltung unterstützen. Tatsächlich beansprucht das Verwalten von Daten, z.B. Datenreinigung und -integration, in vielen datenbezogenen Projekten einen Großteil der Zeit. Die Unterstützung solcher verwaltenden Aktivitäten ist in unserer datengetriebenen Welt insbesondere deswegen sehr wertvoll, weil so mehr Zeit auf die eigentlich wertschöpfende Arbeit mit den Daten verwendet werden kann, z.B. auf das Erstellen analytischer Modelle. Allerdings sind strukturelle Metadaten in den meisten Fällen nicht oder nur unvollständig vorhanden und müssen zunächst extahiert werden. Somit sind effiziente Data-Profiling-Methoden erstrebenswert. Probleme des Data Profiling sind in der Regel sehr berechnungsintensiv: Viele Datenabhängigkeitstypen spannen einen exponentiell in der Anzahl der Attribute wachsenden Suchraum auf. Aus diesem Grund beschreibt die vorliegende Arbeit neue Algorithmen zum Auffinden verschiedener Arten von Datenabhängigkeiten – nämlich Inklusionsabhängigkeiten, bedingter Inklusionsabhängigkeiten, partieller funktionaler Abhängigkeiten sowie partieller eindeutiger Spaltenkombinationen – die bekannte Algorithmen in Effizienz und Skalierbarkeit deutlich übertreffen und somit Datensätze verarbeiten können, an denen bisherige Algorithmen gescheitert sind. Um die Nützlichkeit struktureller Metadaten für die Datenverwaltung zu demonstrieren, stellt diese Arbeit des Weiteren das System Metacrate vor, eine Datenbank für strukturelle Metadaten. Deren besondere Merkmale sind ein flexibles Datenmodell; die Fähigkeit, verschiedene Arten struktureller Metadaten zu integrieren; und eine umfangreiche Bibliothek an Metadatenanalysen. Mithilfe dieser Technologien führen wir eine Datenanamnese unbekannter, komplexer Datensätze durch. Insbesondere beschreiben wir dabei ausführlicher, wie Schemata rekonstruiert und deren Qualität abgeschätzt werden können. Wir haben oben erwähnte Data-Profiling-Algorithmen sowie Metacrate sorgfältig implementiert, mit dem Data-Profiling-Programm Metanome integriert und stellen beide als freie Software zur Verfügung. Dadurch wollen wir nicht nur die Nachvollziehbarkeit unserer Forschungsergebnisse möglichst einfach gestalten, sondern auch deren Einsatz in der Praxis ermöglichen. KW - data profiling KW - metadata KW - inclusion dependencies KW - functional dependencies KW - distributed computation KW - metacrate KW - Data Profiling KW - Metadaten KW - Inklusionsabhängigkeiten KW - funktionale Abhängigkeiten KW - verteilte Berechnung KW - Metacrate Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412521 ER - TY - THES A1 - Brune, Sascha T1 - Modelling continental rift dynamics T1 - Modellierung kontinentaler Riftdynamik N2 - Continental rift systems open up unique possibilities to study the geodynamic system of our planet: geodynamic localization processes are imprinted in the morphology of the rift by governing the time-dependent activity of faults, the topographic evolution of the rift or by controlling whether a rift is symmetric or asymmetric. Since lithospheric necking localizes strain towards the rift centre, deformation structures of previous rift phases are often well preserved and passive margins, the end product of continental rifting, retain key information about the tectonic history from rift inception to continental rupture. Current understanding of continental rift evolution is based on combining observations from active rifts with data collected at rifted margins. Connecting these isolated data sets is often accomplished in a conceptual way and leaves room for subjective interpretation. Geodynamic forward models, however, have the potential to link individual data sets in a quantitative manner, using additional constraints from rock mechanics and rheology, which allows to transcend previous conceptual models of rift evolution. By quantifying geodynamic processes within continental rifts, numerical modelling allows key insight to tectonic processes that operate also in other plate boundary settings, such as mid ocean ridges, collisional mountain chains or subduction zones. In this thesis, I combine numerical, plate-tectonic, analytical, and analogue modelling approaches, whereas numerical thermomechanical modelling constitutes the primary tool. This method advanced rapidly during the last two decades owing to dedicated software development and the availability of massively parallel computer facilities. Nevertheless, only recently the geodynamical modelling community was able to capture 3D lithospheric-scale rift dynamics from onset of extension to final continental rupture. The first chapter of this thesis provides a broad introduction to continental rifting, a summary of the applied rift modelling methods and a short overview of previews studies. The following chapters, which constitute the main part of this thesis feature studies on plate boundary dynamics in two and three dimension followed by global scale analyses (Fig. 1). Chapter II focuses on 2D geodynamic modelling of rifted margin formation. It highlights the formation of wide areas of hyperextended crustal slivers via rift migration as a key process that affected many rifted margins worldwide. This chapter also contains a study of rift velocity evolution, showing that rift strength loss and extension velocity are linked through a dynamic feed-back. This process results in abrupt accelerations of the involved plates during rifting illustrating for the first time that rift dynamics plays a role in changing global-scale plate motions. Since rift velocity affects key processes like faulting, melting and lower crustal flow, this study also implies that the slow-fast velocity evolution should be imprinted in rifted margin structures. Chapter III relies on 3D Cartesian rift models in order to investigate various aspects of rift obliquity. Oblique rifting occurs if the extension direction is not orthogonal to the rift trend. Using 3D lithospheric-scale models from rift initialisation to breakup I could isolate a characteristic evolution of dominant fault orientations. Further work in Chapter III addresses the impact of rift obliquity on the strength of the rift system. We illustrate that oblique rifting is mechanically preferred over orthogonal rifting, because the brittle yielding requires a lower tectonic force. This mechanism elucidates rift competition during South Atlantic rifting, where the more oblique Equatorial Atlantic Rift proceeded to breakup while the simultaneously active but less oblique West African rift system became a failed rift. Finally this Chapter also investigates the impact of a previous rift phase on current tectonic activity in the linkage area of the Kenyan with Ethiopian rift. We show that the along strike changes in rift style are not caused by changes in crustal rheology. Instead the rift linkage pattern in this area can be explained when accounting for the thinned crust and lithosphere of a Mesozoic rift event. Chapter IV investigates rifting from the global perspective. A first study extends the oblique rift topic of the previous chapter to global scale by investigating the frequency of oblique rifting during the last 230 million years. We find that approximately 70% of all ocean-forming rift segments involved an oblique component of extension where obliquities exceed 20°. This highlights the relevance of 3D approaches in modelling, surveying, and interpretation of many rifted margins. In a final study, we propose a link between continental rift activity, diffuse CO2 degassing and Mesozoic/Cenozoic climate changes. We used recent CO2 flux measurements in continental rifts to estimate worldwide rift-related CO2 release, which we based on the global extent of rifts through time. The first-order correlation to paleo-atmospheric CO2 proxy data suggests that rifts constitute a major element of the global carbon cycle. N2 - Kontinentale Grabensysteme eröffnen einzigartige Einsichten in das geodynamische System unseres Planeten: Geodynamische Lokalisierungs-prozesse prägen die Morphologie von Riftsystemen, indem sie die zeitabhängige Aktivität von Störungen, die topographische Entwicklung des Rifts oder dessen Symmetrieentwicklung kontrollieren. Da die Verformung oft in Richtung des Riftzentrums lokalisiert, sind die Deformationsstrukturen früherer Riftphasen meist gut erhalten und passive Ränder, die Endprodukte kontinentalen Riftings, beinhalten wichtige Informationen über die tektonische Geschichte vom Riftbeginn bis zum kontinentalen Zerbrechen. Unser gegenwärtiges Verständnis der Riftentwicklung basiert auf der Kombination von Beobachtungen in aktiven Rifts mit Informationen, die an passiven Kontinental-rändern gesammelt wurden. Die Einbindung dieser isolierten Datensätze erfolgt oft konzeptionell und lässt Raum für subjektive Interpretationen. Geodynamische Vorwärtsmodelle haben jedoch das Potenzial, einzelne Datensätze quantitativ zu verknüpfen, wobei zusätzliche Informationen aus der Gesteinsmechanik und Rheologie verwendet werden, die es ermöglichen, frühere konzeptionelle Riftmodelle weiter zu entwickeln. In dieser Arbeit kombiniere ich numerische, plattentektonische, analytische und analoge Modellierungsansätze, wobei die numerische thermomechanische Modellierung das primäre Werkzeug darstellt. Diese Methode hat sich in den letzten zwei Jahrzehnten aufgrund dedizierter Softwareentwicklung und der Verfügbarkeit von massiv parallelisierten Supercomputern sehr schnell entwickelt. Dennoch gelang es der geodynamischen Modellierungsgemeinschaft erst vor kurzem, die dreidimensionale lithosphärenskalige Riftentwicklung vom Beginn der Dehnung bis zum endgültigen Zerbrechen eines Kontinents zu erfassen. Meine Habilitationsschrift beinhaltet eine Einführung in kontinentale Rifttektonik, eine Zusammenfassung der angewendeten Modellierungsmethoden und einen kurzen Überblick über Vorstudien. In dem Hauptteil dieser Arbeit werden Untersuchungen auf Plattenrandskala in zwei und drei Dimensionen durchgeführt, gefolgt von globalen Analysen der Riftentwicklung. Dabei beschreibe ich die Bildung extrem ausgedehnter kontinentaler Kruste, die an vielen gerifteten Kontinentalrändern beobachtet wurde, die Rückkopplung zwischen Riftdynamik und Plattenbewegungen, der Wirkung von Riftschrägheit und tektonischer Vererbung auf die Riftarchitektur sowie den Einfluss von Riftsystemen auf CO2-Entgasung in Bezug auf die paläoklimatische Entwicklung der Erde seit dem Zerbrechen Pangäas. KW - rifting KW - modelling KW - plate tectonics KW - geodynamics KW - Grabenbruch KW - Modellierung KW - Plattentektonik KW - Geodynamik Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-432364 ER - TY - THES A1 - Choi, Youngeun T1 - DNA origami structures as versatile platforms for nanophotonics T1 - DNA Origami Struktruen als Vielseitige Plattform für Nanophotonik N2 - Nanophotonics is the field of science and engineering aimed at studying the light-matter interactions on the nanoscale. One of the key aspects in studying such optics at the nanoscale is the ability to assemble the material components in a spatially controlled manner. In this work, DNA origami nanostructures were used to self-assemble dye molecules and DNA coated plasmonic nanoparticles. Optical properties of dye nanoarrays, where the dyes were arranged at distances where they can interact by Förster resonance energy transfer (FRET), were systematically studied according to the size and arrangement of the dyes using fluorescein (FAM) as the donor and cyanine 3 (Cy 3) as the acceptor. The optimized design, based on steady-state and time-resolved fluorometry, was utilized in developing a ratiometric pH sensor with pH-inert coumarin 343 (C343) as the donor and pH-sensitive FAM as the acceptor. This design was further applied in developing a ratiometric toxin sensor, where the donor C343 is unresponsive and FAM is responsive to thioacetamide (TAA) which is a well-known hepatotoxin. The results indicate that the sensitivity of the ratiometric sensor can be improved by simply arranging the dyes into a well-defined array. The ability to assemble multiple fluorophores without dye-dye aggregation also provides a strategy to amplify the signal measured from a fluorescent reporter, and was utilized here to develop a reporter for sensing oligonucleotides. By incorporating target capturing sequences and multiple fluorophores (ATTO 647N dye molecules), a reporter for microbead-based assay for non-amplified target oligonucleotide sensing was developed. Analysis of the assay using VideoScan, a fluorescence microscope-based technology capable of conducting multiplex analysis, showed the DNA origami nanostructure based reporter to have a lower limit of detection than a single stranded DNA reporter. Lastly, plasmonic nanostructures were assembled on DNA origami nanostructures as substrates to study interesting optical behaviors of molecules in the near-field. Specifically, DNA coated gold nanoparticles, silver nanoparticles, and gold nanorods, were placed on the DNA origami nanostructure aiming to study surface-enhanced fluorescence (SEF) and surface-enhanced Raman scattering (SERS) of molecules placed in the hotspot of coupled plasmonic structures. N2 - Nanophotonik bezeichnet die Untersuchung von Licht in Wechselwirkung mit Materie im Nanometermaßstab. Die exakte Kontrolle über den Aufbau und die räumliche Anordnung der beteiligten Komponenten ist ein entscheidender Faktor für die Erforschung der Optik nanoskalierter Systeme. Eine mögliche Lösung bietet die selbstorganisatorische Eigenschaft von DNA-Origami-Nanostrukturen, die im Rahmen dieser Dissertation, insbesondere zur Kopplung verschiedener Farbstoffe bzw. plasmonisch aktiver Nanopartikel, verwendet wurden. Im ersten Teil dieser Dissertation wurden unterschiedliche Förster-Resonanzenergietransfer- (FRET) Farbstoff-Matrizen, bestehend aus Fluorescein (FAM) als FRET-Donor und Cyanine 3 (Cy 3) als FRET-Akzeptor, hergestellt und nachfolgend hinsichtlich des Einflusses ihrer Gesamtgröße und ihrer Anordnung via statischer und zeitaufgelöster Fluoreszenzspektroskopie untersucht. Daraufhin erfolgte die Weiterentwicklung der ermittelten optimalen Anordnung der Farbstoffe in einen ratiometrischen pH-Sensor, bestehend aus dem pH stabilen Coumarin 343 (C343) als FRET-Donor und dem pH sensitiven FAM als FRET-Akzeptor. Die erhaltenen Ergebnisse zeigten, dass sich die Sensitivität ratiometrischer Sensoren, insbesondere durch die wohldefinierte Anordnung der beteiligten Farbstoffe in der Matrize, deutlich steigern lassen. Selbige Anordnung konnte auch erfolgreich zur Entwicklung eines Giftstoffsensors, zum Nachweis des Hepatoxins Thioacetamid (TAA), verwendet werden. Die Möglichkeit der Anordnung mehrerer Farbstoffe, unter Vermeidung ungewollter Farbstoff-Aggregation, ermöglicht außerdem die Verstärkung der Signale sogenannter Fluoreszenzreporter. Dies führte, im Rahmen dieser Arbeit, zur erfolgreichen Entwicklung eines auf Mikroperlen basierenden Oligonukleotid-Sensors, welcher ohne die Notwendigkeit einer vorherigen Zielverstärkung (z.B. durch Polymerase-Kettenreaktion) auskommt. Die anschließende Analyse mittels VideoScan, einer Multiplex-Analyse-Technik basierend auf der Fluoreszenzmikroskopie, ergab deutlich niedrigere Nachweisgrenzen für auf DNA-Origami basierende Reporter im Vergleich zu DNA-Einzelstrang basierenden Reportern. Abschließend erfolgte die Verwendung der DNA-Origamis als Substrat für die präzise räumliche Anordnung verschiedener plasmonisch aktiver Nanopartikel zur Untersuchung des optischen Verhaltens von Zielmolekülen im plasmonischen Nahfeld. Die Untersuchung der oberflächenverstärkten Fluoreszenz (SEF) und oberflächenverstärkten Raman-Streuung (SERS) von Molekülen im plasmonischer Hotspots erfolgte insbesondere mit Fokus auf den Einfluss der unterschiedlichen Anordnung von Gold-Nanostäbchen, Gold-Nanopartikel, und Silber-Nanopartikel. KW - DNA origami KW - Förster resonance energy transfer KW - plasmonics KW - DNA Origami KW - Förster-Resonanzenergietransfer KW - Plasmonik Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-421483 ER - TY - THES A1 - Vogel, Stefanie T1 - Sequence dependency of photon and electron induced DNA strand breaks T1 - Sequenzabhängigkeit von photonen-und elektroneninduzierten DNA Strangbrüchen N2 - Deoxyribonucleic acid (DNA) is the carrier of human genetic information and is exposed to environmental influences such as the ultraviolet (UV) fraction of sunlight every day. The photostability of the DNA against UV light is astonishing. Even if the DNA bases have a strong absorption maximum at around 260 nm/4.77 eV, their quantum yield of photoproducts remains very low 1. If the photon energies exceed the ionization energy (IE) of the nucleobases ( ̴ 8-9 eV) 2, the DNA can be severely damaged. Photoexcitation and -ionization reactions occur, which can induce strand breaks in the DNA. The efficiency of the excitation and ionization induced strand breaks in the target DNA sequences are represented by cross sections. If Si as a substrate material is used in the VUV irradiation experiments, secondary electrons with an energy below 3.6 eV are generated from the substrate. This low energy electrons (LEE) are known to induce dissociative electron attachment (DEA) in DNA and with it DNA strand breakage very efficiently. LEEs play an important role in cancer radiation therapy, since they are generated secondarily along the radiation track of ionizing radiation. In the framework of this thesis, different single stranded DNA sequences were irradiated with 8.44 eV vacuum UV (VUV) light and cross sections for single strand breaks (SSB) were determined. Several sequences were also exposed to secondary LEEs, which additionally contributed to the SSBs. First, the cross sections for SSBs depending on the type of nucleobases were determined. Both types of DNA sequences, mono-nucleobase and mixed sequences showed very similar results upon VUV radiation. The additional influence of secondarily generated LEEs resulted in contrast in a clear trend for the SSB cross sections. In this, the polythymine sequence had the highest cross section for SSBs, which can be explained by strong anionic resonances in this energy range. Furthermore, SSB cross sections were determined as a function of sequence length. This resulted in an increase in the strand breaks to the same extent as the increase in the geometrical cross section. The longest DNA sequence (20 nucleotides) investigated in this series, however, showed smaller cross section values for SSBs, which can be explained by conformational changes in the DNA. Moreover, several DNA sequences that included the radiosensitizers 5-Bromouracil (5BrU) and 8-Bromoadenine (8BrA) were investigated and the corresponding SSB cross sections were determined. It was shown that 5BrU reacts very strongly to VUV radiation leading to high strand break yields, which showed in turn a strong sequence-dependency. 8BrA, on the other hand, showed no sensitization to the applied VUV radiation, since almost no increase in strand breakage yield was observed in comparison to non-modified DNA sequences. In order to be able to identify the mechanisms of radiation damage by photons, the IEs of certain DNA sequences were further explored using photoionization tandem mass spectrometry. By varying the DNA sequence, both the IEs depending on the type of nucleobase as well as on the DNA strand length could be identified and correlated to the SSB cross sections. The influence of the IE on the photoinduced reaction in the brominated DNA sequences could be excluded. N2 - Desoxyribonukleinsäure (DNA) ist als Träger der menschlichen Erbinformation täglich vielen Einflüssen ausgesetzt. Diese Einflüsse können Teil unserer Umwelt sein, wie der ultraviolette (UV) Anteil des Sonnenlichts. Die Photostabilität der DNA gegen UV-Licht ist erstaunlich, denn trotz eines starkes Absorptionsmaximum der DNA-Basen bei etwa 260 nm/4,77 eV, bleibt ihre Quantenausbeute an Photoprodukten sehr gering 1. Überschreiten die Photonenenergien die Ionisationsenergie (IE) der Nukleinbasen ( ̴ 8-9 eV) 2, kann die DNA schwer geschädigt werden. Es treten Anregungs- und Ionisierungsreaktionen auf, die zu Strangbrüchen in der DNA führen. Die Effizienz der induzierten Strangbrüche in den untersuchten DNA-Sequenzen wird durch Wirkungsquerschnitte dargestellt. Wird in den Bestrahlungsexperimenten Silizium als Substratmaterial verwendet, werden aus dem Substrat zusätzliche Sekundärelektronen mit einer Energie unter 3,6 eV erzeugt, die weiteren Schaden an der DNA verursachen. Diese niederenergetischen Elektronen (LEE) sind dafür bekannt, dissoziative Elektronenanlagerung (DEA) und damit Strangbrüche in der DNA zu erzeugen. LEEs entstehen sekundär entlang des Strahlungsweges von ionisierender Strahlung im biologischen Gewebe, wenn in der Behandlung der Krankheit Krebs Strahlentherapie eingesetzt wird. Im Rahmen dieser Arbeit wurden verschiedene Einzelstrang-DNA-Sequenzen mit 8.44 eV Vakuum-UV (VUV) Licht bestrahlt und Wirkungsquerschnitte für Einzel-strangbrüche (SSB) bestimmt. Ein Teil der Sequenzen wurde außerdem sekundär erzeugten LEEs ausgesetzt, die einen zusätzlichen Beitrag zu den SSBs liefern. Als erstes wurde der Wirkungsquerschnitt für SSBs in Abhängigkeit der Nukleinbasen bestimmt. Hierbei weisen sowohl die DNA Sequenzen, die nur ein Sorte an Nukleinbasen besitzen als auch die gemischte Sequenzen sehr ähnliche Werte auf. Durch den zusätzlichen Einfluss der LEEs hat sich wiederum für die DNA Sequenzen mit nur einer Sorte an Nukleinbasen ein stark ausgeprägter Trend gezeigt. Die Polythymin-Sequenz weist den höchsten Wirkungsquerschnitt für SSBs auf, was durch ausgeprägte anionische Resonanzen in diesem Energiebereich begründet werden kann. Des Weiteren wurden Wirkungsquerschnitte für SSBs in Abhängigkeit Sequenzlänge ermittelt. Dabei ergab sich eine Erhöhung der SSBs im gleichen Maße wie die Vergrößerung des geometrischen Wirkungsquerschnitts. Die längste DNA Sequenz (20 Nukleotide), die in dieser Reihe untersucht wurde, zeigte hingegen kleinere Werte für den SSB Wirkungsquerschnitt, was durch Konformationsänderungen in der DNA erklärt werden kann. Einige der untersuchten DNA Sequenzen wurden zusätzlich mit den Radiosensibilisatoren 5-Bromouracil (5BrU) und 8-Bromoadenine (8BrA) modifiziert und entsprechende SSB Wirkungsquerschnitte bestimmt. Hierbei hat sich gezeigt, dass 5BrU mittels einer hohen Strangbruchausbeute sehr stark auf VUV Strahlung reagiert, wobei das Ausmaß der Reaktion stark sequenzabhängig ist. 8BrA hingegen, weist keine Sensibilisierung gegenüber der verwendeten VUV Strahlung auf, da keine Erhöhung der Strangbruchausbeute gegenüber unmodifizierten DNA Sequenzen ersichtlich ist. Um die Mechanismen der Strahlenschädigung durch Photonen besser einschätzen zu können, wurden zusätzlich die IEs bestimmter DNA Sequenzen mit Hilfe der Photoionisations-Tandem-Massenspektrometrie untersucht. Durch Variation der DNA-Sequenzen konnte sowohl ein Trend der IEs in Abhängigkeit der Nukleinbasen und der DNA-Stranglänge identifiziert und als auch eine Abhängigkeit der Reaktivität von 5BrU von seinem IE in der entsprechenden DNA Sequenz ausgeschlossen werden. Die IE Trends und die Wirkungsquerschnitte für SSBs wurden abschließend in Korrelation gebracht. KW - DNA KW - photo ionization KW - dissociative electron attachment KW - DNA origami KW - radiosensitizer KW - ionization energy KW - tandem mass spectrometry KW - DNS KW - Photoionisation KW - Dissoziative Elektronenanlagerung KW - DNA Origami KW - Radiosensibilisator KW - Ionisierungsenergie KW - Tandemmassenspektrometrie Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419669 ER - TY - THES A1 - Behrendt, Felix Nicolas T1 - New bio-based polymers T1 - Neue biobasierte Polymere BT - synthesis and polymerization of cystine-based macrocycles BT - Synthese und Polymerisation von cystinbasierten Makrozyklen N2 - Redox-responsive polymers, such as poly(disulfide)s, are a versatile class of polymers with potential applications including gene- and drug-carrier systems. Their degradability under reductive conditions allows for a controlled response to the different redox states that are present throughout the body. Poly(disulfide)s are typically synthesized by step growth polymerizations. Step growth polymerizations, however, may suffer from low conversions and therefore low molar masses, limiting potential applications. The purpose of this thesis was therefore to find and investigate new synthetic routes towards the synthesis of amino acid-based poly(disulfide)s. The different routes in this thesis include entropy-driven ring opening polymerizations of novel macrocyclic monomers, derived from cystine derivatives. These monomers were obtained with overall yields of up to 77% and were analyzed by mass spectrometry as well as by 1D and 2D NMR spectroscopy. The kinetics of the entropy-driven ring-opening metathesis polymerization (ED-ROMP) were thoroughly investigated in dependence of temperature, monomer concentration, and catalyst concentration. The polymerization was optimized to yield poly(disulfide)s with weight average molar masses of up to 80 kDa and conversions of ~80%, at the thermodynamic equilibrium. Additionally, an alternative metal free polymerization, namely the entropy-driven ring-opening disulfide metathesis polymerization (ED-RODiMP) was established for the polymerization of the macrocyclic monomers. The effect of different solvents, concentrations and catalyst loadings on the polymerization process and its kinetics were studied. Polymers with very high weight average molar masses of up to 177 kDa were obtained. Moreover, various post-polymerization reactions were successfully performed. This work provides the first example of the homopolymerization of endo-cyclic disulfides by ED-ROMP and the first substantial study into the kinetics of the ED-RODiMP process. N2 - Redoxresponsive Polymere, wie etwa Polydisulfide, sind eine vielseitige Klasse von Polymeren, die unter anderem als Gen- und Wirkstoffträgersysteme eingesetzt werden können. Ihre Abbaubarkeit unter reduktiven Bedingungen ermöglicht eine kontrollierte Reaktion auf die verschiedenen Redoxzustände im Körper. Polydisulfide werden jedoch häufig durch Stufenwachstums-polymerisationen synthetisiert. Diese führen oft zu niedrigen Umsätzen und daher zu niedrigen molaren Massen. Das Ziel dieser Arbeit war daher neue Synthesewege für aminosäurebasierte Polydisulfide zu finden und zu untersuchen. Diese Wege beinhalteten entropiegetriebene ringöffnende Polymerisationen von neuen makrozyklischen Monomeren, auf der Basis von Cystin-Derivaten. Diese Monomere konnten mit einer Gesamtausbeute von bis zu 77% synthetisiert werden und wurden mit Massenspektrometrie sowie mit 1D- und 2D-NMR-Spektroskopie analysiert. Die Kinetik der entropiegetriebenen ringöffnenden Metathese Polymerisation (ED-ROMP) wurde im Hinblick auf Temperatur, Monomerkonzentration und Katalysatormenge sorgfältig untersucht. Durch Optimierungen konnten Polydisulfide mit gewichtsmittleren Molmassen von bis zu 80 kDa und Umsätzen von ~80%, im thermodynamischen Gleichgewicht synthetisiert werden. Zusätzlich wurde eine alternative metallfreie Polymerisation, die entropiegetriebene ringöffnende Disulfidmetathese Polymerisation (ED-RODiMP), für die Polymerisation der makrozyklischen Monomere etabliert. Die Auswirkungen verschiedener Lösungsmittel, Konzentrationen und Katalysatorkonzentrationen auf die Kinetik dieses Polymerisationsprozesses wurden untersucht. Hierdurch wurden Polymere mit sehr hohen gewichtsmittleren Molmassen von bis zu 177 kDa erhalten. Darüber hinaus wurden verschiedene Postpolymerisationsreaktionen erfolgreich durchgeführt. Diese Arbeit liefert das erste Beispiel für die Homopolymerisation endo-zyklischer Disulfide durch ROMP und eine erste substanzielle Studie der Kinetik des ED-RODiMP-Prozesses. KW - polymers KW - ADMET KW - ROMP KW - disulfide KW - macrocycles KW - ring-opening polymerization KW - amino acids KW - Polymere KW - ADMET KW - ROMP KW - Disulfide KW - Makrozyklen KW - ringöffnende Polymerisation KW - Aminosäuren Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-418316 ER - TY - THES A1 - Kumru, Baris T1 - Utilization of graphitic carbon nitride in dispersed media T1 - Anwendung von graphitischem Kohlenstoffnitrid in dispergierten Medien N2 - Utilization of sunlight for energy harvesting has been foreseen as sustainable replacement for fossil fuels, which would also eliminate side effects arising from fossil fuel consumption such as drastic increase of CO2 in Earth atmosphere. Semiconductor materials can be implemented for energy harvesting, and design of ideal energy harvesting devices relies on effective semiconductor with low recombination rate, ease of processing, stability over long period, non-toxicity and synthesis from abundant sources. Aforementioned criteria have attracted broad interest for graphitic carbon nitride (g-CN) materials, metal-free semiconductor which can be synthesized from low cost and abundant precursors. Furthermore, physical properties such as band gap, surface area and absorption can be tuned. g-CN was investigated as heterogeneous catalyst, with diversified applications from water splitting to CO2 reduction and organic coupling reactions. However, low dispersibility of g-CN in water and organic solvents was an obstacle for future improvements. Tissue engineering aims to mimic natural tissues mechanically and biologically, so that synthetic materials can replace natural ones in future. Hydrogels are crosslinked networks with high water content, therefore are prime candidates for tissue engineering. However, the first requirement is synthesis of hydrogels with mechanical properties that are matching to natural tissues. Among different approaches for reinforcement, nanocomposite reinforcement is highly promising. This thesis aims to investigate aqueous and organic dispersions of g-CN materials. Aqueous g-CN dispersions were utilized for visible light induced hydrogel synthesis, where g-CN acts as reinforcer and photoinitiator. Varieties of methodologies were presented for enhancing g-CN dispersibility, from co-solvent method to prepolymer formation, and it was shown that hydrogels with diversified mechanical properties (from skin-like to cartilage-like) are accessible via g-CN utilization. One pot photografting method was introduced for functionalization of g-CN surface which provides functional groups towards enhanced dispersibility in aqueous and organic media. Grafting vinyl thiazole groups yields stable additive-free organodispersions of g-CN which are electrostatically stabilized with increased photophysical properties. Colloidal stability of organic systems provides transparent g-CN coatings and printing g-CN from commercial inkjet printers. Overall, application of g-CN in dispersed media is highly promising, and variety of materials can be accessible via utilization of g-CN and visible light with simple chemicals and synthetic conditions. g-CN in dispersed media will bridge emerging research areas from tissue engineering to energy harvesting in near future. N2 - Sonnenlicht kann fossile Brennstoffe in der Energieerzeugung ersetzen und ermöglicht neben der Nutzung einer nachhaltigen Ressource dabei auch die deutliche Reduktion der Umweltbelastung in der Energieerzeugung. Die Verfügbarkeit geeigneter Energiegewinnungstechnologien hängt entscheidend von der Verfügbarkeit geeigneter Superkondensatoren (SC) ab. Ideale SC sollten sich in diesem Zusammenhang durch eine geringe Rekombinationsrate, gute Verarbeitbarkeit, Langzeitstabilität, Ungiftigkeit und die Verfügbarkeit aus nachhaltigen Ressourcen auszeichnen. Graphitisches Kohlenstoffnitrid (graphitic carbon nitride – g-CN), ein metall-freier Halbleiter, der aus nachhaltigen und in großer Menge verfügbaren Ausgangsstoffen hergestellt werden kann, ist als Material für dieses Eigenschaftsprofil hervorragend geeignet. Darüber hinaus können die Eigenschaften dieses Materials (innere Oberfläche, Bandlücke, Lichtabsorption) eingestellt werden. Daraus ergibt sich ein großes Forschungsinteresse z.B. im Bereich heterogener Katalyse, wie in der Kohlenstoffdioxidreduktion, elektrolytischen Wasserspaltung und verschiedener organischer Kupplungsreaktionen. Unglücklicherweise ist die schlechte Dispergierbarkeit von g-CN in organischen Lösungsmitteln und Wasser ein wesentlicher Hinderungsgrund für die erfolgreiche Nutzbarmachung dieser hervorragenden Eigenschaften. Das Design von Materialien, die biologisches Gewebe in seinen mechanischen und biologischen Eigenschaften nachahmen und ersetzen können, ist das Ziel der Gewebekonstruktion (Tissue Engineering – TE). Hydrogele, also Netzwerke mit hohem Wassergehalt, gelten als die vielversprechendsten Materialen in diesem Forschungsfeld. Die Herstellung von Hydrogelen, die biologischem Gewebe in seinen mechanischen Eigenschaften ähnelt gilt allerdings als äußerst schwierig und erfordert die Stabilisierung der Netzwerke. Besonders der Einsatz von Nanoverbundstrukturen (nanocomposites) erscheint in diesem Zusammenhang vielversprechend. Die vorliegende Arbeit beschäftigt sich mit der Untersuchung von g-CN in sowohl wässrigen, als auch organischen Dispersionen. Im Zuge dessen werden wässrige Dispersionen für die Synthese von Hydrogelen, bei der g-CN sowohl als Photoinitiator für die durch sichtbares Licht ausgelöste Vernetzung, als auch als Strukturverstärker fungiert. Zur Verbesserung der Dispergierbarkeit des g CN werden vielseitige Ansätze präsentiert, welche von der Verwendung von Co-Lösungsmitteln bis zur Präpolymerbildung reichen. Durch die aufgezeigten Ansätze können Hydrogele mit unterschiedlichen mechanischen Eigenschaften hergestellt werden (hautartig bis knorpelig). Darüber hinaus wird eine Ein-Topf Synthese für die Oberflächenfunktionalisierung vorgestellt, durch die die Dispergierbarkeit von g-CN in organischen und wässrigen Medien verbessert werden kann. Beispielsweise erlaubt die Oberflächenfunktionalisierung mit Vinylthiazol die Herstellung von kolloidal dispergiertem g-CN mit verbesserten photophysikalischen Eigenschaften ohne zusätzliche Additive und eröffnet damit die Möglichkeit transparenter g-CN Beschichtungen und ermöglicht die Druckbarkeit von g-CN aus handelsüblichen Tintenstrahldruckern. Die Anwendung von g-CN in dispergierten Medien ist vielversprechend, da eine große Zahl sehr vielfältiger Materialien durch die Kombination von g-CN mit sichtbarem Licht aus günstigen, nachhaltigen Ressourcen verfügbar ist. Daher ist zu erwarten, dass g-CN in dispergierten Medien verschiedene im Entstehen begriffene Forschungsfelder von TE bis zur Energiegewinnung überspannen wird. KW - polymer chemistry KW - Polymerchemie KW - photochemistry KW - Photochemie KW - colloid chemistry KW - kolloidchemie KW - hydrogels KW - Hydrogelen Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-427339 ER - TY - THES A1 - Rothkegel, Lars Oliver Martin T1 - Human scanpaths in natural scene viewing and natural scene search T1 - Menschliche Blickspuren beim Betrachten und Durchsuchen natürlicher Szenen BT - the role of systematic eye-movement tendencies N2 - Understanding how humans move their eyes is an important part for understanding the functioning of the visual system. Analyzing eye movements from observations of natural scenes on a computer screen is a step to understand human visual behavior in the real world. When analyzing eye-movement data from scene-viewing experiments, the impor- tant questions are where (fixation locations), how long (fixation durations) and when (ordering of fixations) participants fixate on an image. By answering these questions, computational models can be developed which predict human scanpaths. Models serve as a tool to understand the underlying cognitive processes while observing an image, especially the allocation of visual attention. The goal of this thesis is to provide new contributions to characterize and model human scanpaths on natural scenes. The results from this thesis will help to understand and describe certain systematic eye-movement tendencies, which are mostly independent of the image. One eye-movement tendency I focus on throughout this thesis is the tendency to fixate more in the center of an image than on the outer parts, called the central fixation bias. Another tendency, which I will investigate thoroughly, is the characteristic distribution of angles between successive eye movements. The results serve to evaluate and improve a previously published model of scanpath generation from our laboratory, the SceneWalk model. Overall, six experiments were conducted for this thesis which led to the following five core results: i) A spatial inhibition of return can be found in scene-viewing data. This means that locations which have already been fixated are afterwards avoided for a certain time interval (Chapter 2). ii) The initial fixation position when observing an image has a long-lasting influence of up to five seconds on further scanpath progression (Chapter 2 & 3). iii) The often described central fixation bias on images depends strongly on the duration of the initial fixation. Long-lasting initial fixations lead to a weaker central fixation bias than short fixations (Chapter 2 & 3). iv) Human observers adjust their basic eye-movement parameters, like fixation dura- tions and saccade amplitudes, to the visual properties of a target they look for in visual search (Chapter 4). v) The angle between two adjacent saccades is an indicator for the selectivity of the upcoming saccade target (Chapter 4). All results emphasize the importance of systematic behavioral eye-movement tenden- cies and dynamic aspects of human scanpaths in scene viewing. N2 - Die Art und Weise, wie wir unsere Augen bewegen, ist ein bedeutender Aspekt des visuellen Systems. Die Analyse von Augenbewegungen beim Betrachten natürlicher Szenen auf einem Bildschirm soll helfen, natürliches Blickverhalten zu verstehen. Durch Beantwortung der Fragen wohin (Fixationsposition), wie lange (Fixationsdauern) und wann (Reihenfolge von Fixationen) Versuchspersonen auf einem Bild fixieren, lassen sich computationale Modelle entwickeln, welche Blickspuren auf natürlichen Bildern vorhersagen. Modelle sind ein Werkzeug, um zugrunde liegende kognitive Prozesse, insbesondere die Zuweisung visueller Aufmerksamkeit, während der Betrachtung von Bildern zu verstehen. Das Ziel der hier vorliegenden Arbeit ist es, neue Beitr¨age zur Modellierung und Charakterisierung menschlicher Blickspuren auf natürlichen Szenen zu liefern. Speziell systematische Blicksteuerungstendenzen, welche größtenteils unabhängig vom betrachteten Bild sind, sollen durch die vorliegenden Studien besser verstanden und beschrieben werden. Eine dieser Tendenzen, welche ich gezielt untersuche, ist die Neigung von Versuchspersonen, die Mitte eines Bildes häufiger als äußere Bildregionen zu fixieren. Außerdem wird die charakteristische Verteilung der Winkel zwischen zwei aufeinanderfolgenden Sakkaden systematisch untersucht. Die Ergebnisse dienen der Evaluation und Verbesserung des SceneWalk Modells für Blicksteuerung aus unserer Arbeitsgruppe. Insgesamt wurden 6 Experimente durchgeführt, welche zu den folgenden fünf Kernbefunden führten: i) Ein örtlicher inhibition of return kann in Blickbewegungsdaten von Szenenbetrachtungsexperimenten gefunden werden. Das bedeutet, fixierte Positionen werden nach der Fixation für einen bestimmten Zeitraum gemieden (Kapitel 2). ii) Die Startposition der Betrachtung eines Bildes hat einen langanhaltenden Einfluss von bis zu fünf Sekunden auf die nachfolgende Blickspur (Kapitel 2 & 3). iii) Die viel beschriebene zentrale Fixationstendenz auf Bildern hängt davon ab, wie lange die erste Fixation dauert. Lange initiale Fixationen führen zu deutlich geringerer zentraler Fixationstendenz als kurze Fixationen (Kapitel 2 & 3). iv) Menschliche Betrachter passen Fixationsdauern und Sakkadenamplituden an die visuellen Eigenschaften eines Zielreizes in visueller Suche an (Kapitel 4). v) Der Winkel zwischen zwei Sakkaden ist ein Indikator dafür, wie selektiv das Ziel der zweiten Sakkade ist (Kapitel 4). Alle Ergebnisse betonen die Wichtigkeit von systematischem Blickbewegungsverhalten und dynamischen Aspekten menschlicher Blickspuren beim Betrachten von natürlichen Szenen. KW - eye movements KW - scene viewing KW - computational modeling KW - scanpaths KW - visual attention KW - Augenbewegungen KW - Szenenbetrachtung KW - Computationale Modellierung KW - Blickspuren KW - Visuelle Aufmerksamkeit Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-420005 ER - TY - THES A1 - Stettner, Samuel T1 - Exploring the seasonality of rapid Arctic changes from space T1 - Erkundung der Saisonalität schneller arktischer Veränderungen aus dem Weltraum BT - monitoring of permafrost disturbance, snow cover and vegetation in tundra environments with TerraSAR-X BT - Überwachung von Permafroststörungen, Schneebedeckung und Vegetation in Tundra-Umgebungen mit TerraSAR-X N2 - Arctic warming has implications for the functioning of terrestrial Arctic ecosystems, global climate and socioeconomic systems of northern communities. A research gap exists in high spatial resolution monitoring and understanding of the seasonality of permafrost degradation, spring snowmelt and vegetation phenology. This thesis explores the diversity and utility of dense TerraSAR-X (TSX) X-Band time series for monitoring ice-rich riverbank erosion, snowmelt, and phenology of Arctic vegetation at long-term study sites in the central Lena Delta, Russia and on Qikiqtaruk (Herschel Island), Canada. In the thesis the following three research questions are addressed: • Is TSX time series capable of monitoring the dynamics of rapid permafrost degradation in ice-rich permafrost on an intra-seasonal scale and can these datasets in combination with climate data identify the climatic drivers of permafrost degradation? • Can multi-pass and multi-polarized TSX time series adequately monitor seasonal snow cover and snowmelt in small Arctic catchments and how does it perform compared to optical satellite data and field-based measurements? • Do TSX time series reflect the phenology of Arctic vegetation and how does the recorded signal compare to in-situ greenness data from RGB time-lapse camera data and vegetation height from field surveys? To answer the research questions three years of TSX backscatter data from 2013 to 2015 for the Lena Delta study site and from 2015 to 2017 for the Qikiqtaruk study site were used in quantitative and qualitative analysis complimentary with optical satellite data and in-situ time-lapse imagery. The dynamics of intra-seasonal ice-rich riverbank erosion in the central Lena Delta, Russia were quantified using TSX backscatter data at 2.4 m spatial resolution in HH polarization and validated with 0.5 m spatial resolution optical satellite data and field-based time-lapse camera data. Cliff top lines were automatically extracted from TSX intensity images using threshold-based segmentation and vectorization and combined in a geoinformation system with manually digitized cliff top lines from the optical satellite data and rates of erosion extracted from time-lapse cameras. The results suggest that the cliff top eroded at a constant rate throughout the entire erosional season. Linear mixed models confirmed that erosion was coupled with air temperature and precipitation at an annual scale, seasonal fluctuations did not influence 22-day erosion rates. The results highlight the potential of HH polarized X-Band backscatter data for high temporal resolution monitoring of rapid permafrost degradation. The distinct signature of wet snow in backscatter intensity images of TSX data was exploited to generate wet snow cover extent (SCE) maps on Qikiqtaruk at high temporal resolution. TSX SCE showed high similarity to Landsat 8-derived SCE when using cross-polarized VH data. Fractional snow cover (FSC) time series were extracted from TSX and optical SCE and compared to FSC estimations from in-situ time-lapse imagery. The TSX products showed strong agreement with the in-situ data and significantly improved the temporal resolution compared to the Landsat 8 time series. The final combined FSC time series revealed two topography-dependent snowmelt patterns that corresponded to in-situ measurements. Additionally TSX was able to detect snow patches longer in the season than Landsat 8, underlining the advantage of TSX for detection of old snow. The TSX-derived snow information provided valuable insights into snowmelt dynamics on Qikiqtaruk previously not available. The sensitivity of TSX to vegetation structure associated with phenological changes was explored on Qikiqtaruk. Backscatter and coherence time series were compared to greenness data extracted from in-situ digital time-lapse cameras and detailed vegetation parameters on 30 areas of interest. Supporting previous results, vegetation height corresponded to backscatter intensity in co-polarized HH/VV at an incidence angle of 31°. The dry, tall shrub dominated ecological class showed increasing backscatter with increasing greenness when using the cross polarized VH/HH channel at 32° incidence angle. This is likely driven by volume scattering of emerging and expanding leaves. Ecological classes with more prostrate vegetation and higher bare ground contributions showed decreasing backscatter trends over the growing season in the co-polarized VV/HH channels likely a result of surface drying instead of a vegetation structure signal. The results from shrub dominated areas are promising and provide a complementary data source for high temporal monitoring of vegetation phenology. Overall this thesis demonstrates that dense time series of TSX with optical remote sensing and in-situ time-lapse data are complementary and can be used to monitor rapid and seasonal processes in Arctic landscapes at high spatial and temporal resolution. N2 - Die Erwärmung der Arktis hat Auswirkungen auf die Stabilität und Funktion terrestrischer arktischer Ökosysteme, auf das globale Klima, sowie auf sozioökonomische Systeme nördlicher Gemeinden. Es besteht eine Forschungslücke bei der Überwachung der Saisonalität von Permafrostdegradation, Schneebedeckung und Vegetationsphänologie. Diese Dissertation untersucht den Nutzen von TerraSAR-X (TSX) X-Band Daten für die Überwachung eisreicher Ufererosion, Schneeschmelze, sowie Phänologie arktischer Vegetation im zentralen Lena Delta in Russland und auf Qikiqtaruk (Herschel Island), Kanada. Die Dynamik intrasaisonaler eisreicher Ufererosion im zentralen Lena-Delta in Russland wurde mit TSX Rückstreuintensitätsbildern quantifiziert und mit optischen Satelliten-Daten und Feldmessungen validiert. Kliff Kanten wurden automatisch aus TSX-Intensitätsbildern extrahiert und in einem Geoinformationssystem mit manuell digitalisierten Kliff Kanten aus optischen Satellitendaten, sowie mit Erosionsraten aus Zeitrafferkameras zusammengeführt. Die Ergebnisse deuten darauf hin, dass sich die Kliff Kante während der gesamten Auftauzeit mit konstanter Geschwindigkeit zurückzog. Die Verwendung von linearen Mischmodellen bestätigte, dass die Erosion im jährlichen Maßstab mit der Lufttemperatur und dem Niederschlag gekoppelt war, saisonale Schwankungen beeinflussten die Erosionsrate nicht. Die Ergebnisse stützen die Verwendung von TSX zur Überwachung schneller Permafrostdegradation mit hoher zeitlicher Auflösung. Die eindeutige Signatur von nassem Schnee in TSX Rückstreuintensitätsbildern wurde genutzt, um Schneeverteilungskarten (SCE) auf Qikiqtaruk in hoher zeitlicher Auflösung zu erzeugen. Aus TSX abgeleitete SCE zeigten eine große Ähnlichkeit zu SCE aus Landsat 8 Daten. Zeitreihen von prozentualer Schneebedeckung (FSC) wurden aus TSX und optischen SCE extrahiert und mit FSC-Schätzungen aus in-situ Zeitrafferkamera Daten verglichen. Auch hier zeigte TSX eine starke Übereinstimmung mit den in-situ-Daten und verbesserte die zeitliche Auflösung im Vergleich zur Landsat 8 Zeitreihe erheblich. Aus einer finalen kombinierten FSC-Zeitreihe konnten zwei Muster von Schneeschmelzen in ausgewählten Einzugsgebieten abgeleitet werden, die sich mit den in-situ Messungen deckten. Zusätzlich konnte TSX später in der Saison Schnee länger erkennen als Landsat 8, was den Vorteil von TSX zur Erkennung von Altschnee unterstreicht. Die TSX-abgeleiteten Schnee-Informationen lieferten wertvolle Einblicke in die Schneeschmelz-Dynamik auf Qikiqtaruk, welche zuvor nicht verfügbar waren. Die Empfindlichkeit von TSX für Vegetationsstruktur, die mit phänologischen Veränderungen einhergeht, wurde auf Qikiqtaruk untersucht. Rückstreu- und Kohärenzzeitreihen wurden aus 30 Testgebieten extrahiert. Die Rückstreu- und Kohärenzsignale wurden mit Vitalitäts-Daten verglichen, die aus in-situ-Zeitrafferkamera Zeitreihen extrahiert wurden. Die Ergebnisse zeigten einen Zusammenhang zwischen Vegetationshöhe und der Rückstreuintensität in HH / VV polarisierten Daten bei einem Einfallswinkel von 31 °. Ferner zeigte die ökologische Klasse mit einer Kombination von hohen Sträuchern und trockenen Oberflächenbedingungen eine zunehmende Rückstreuung mit zunehmende Pflanzenvitalität, wenn der kreuzpolarisierte VH / HH-Kanal bei 32 ° Einfallswinkel verwendet wurde. Die Ergebnisse aus strauchdominierten Klassen sind vielversprechend und liefern eine ergänzende Datenquelle für zeitlich hochaufgelöste Beobachtung der Vegetationsphänologie. Insgesamt zeigt diese Arbeit, dass TSX X-Band-Daten schnelle und saisonale Prozesse in arktischen Landschaften mit hoher räumlicher und zeitlicher Auflösung überwachen können. KW - SAR KW - remote sensing KW - arctic KW - SAR KW - Fernerkundung KW - Arktis Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-425783 ER - TY - GEN A1 - Henkel, Janin A1 - Alfine, Eugenia A1 - Saín, Juliana A1 - Jöhrens, Korinna A1 - Weber, Daniela A1 - Castro, José Pedro A1 - König, Jeannette A1 - Stuhlmann, Christin A1 - Vahrenbrink, Madita A1 - Jonas, Wenke A1 - Kleinridders, André A1 - Püschel, Gerhard Paul T1 - Soybean Oil-Derived Poly-Unsaturated Fatty Acids Enhance Liver Damage in NAFLD Induced by Dietary Cholesterol T2 - Nutrients N2 - While the impact of dietary cholesterol on the progression of atherosclerosis has probably been overestimated, increasing evidence suggests that dietary cholesterol might favor the transition from blunt steatosis to non-alcoholic steatohepatitis (NASH), especially in combination with high fat diets. It is poorly understood how cholesterol alone or in combination with other dietary lipid components contributes to the development of lipotoxicity. The current study demonstrated that liver damage caused by dietary cholesterol in mice was strongly enhanced by a high fat diet containing soybean oil-derived ω6-poly-unsaturated fatty acids (ω6-PUFA), but not by a lard-based high fat diet containing mainly saturated fatty acids. In contrast to the lard-based diet the soybean oil-based diet augmented cholesterol accumulation in hepatocytes, presumably by impairing cholesterol-eliminating pathways. The soybean oil-based diet enhanced cholesterol-induced mitochondrial damage and amplified the ensuing oxidative stress, probably by peroxidation of poly-unsaturated fatty acids. This resulted in hepatocyte death, recruitment of inflammatory cells, and fibrosis, and caused a transition from steatosis to NASH, doubling the NASH activity score. Thus, the recommendation to reduce cholesterol intake, in particular in diets rich in ω6-PUFA, although not necessary to reduce the risk of atherosclerosis, might be sensible for patients suffering from non-alcoholic fatty liver disease. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 479 KW - non-alcoholic fatty liver disease (NAFLD) KW - NASH KW - cholesterol KW - PUFA KW - inflammation KW - oxidative stress Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419773 ER - TY - THES A1 - Stolle, Amelie T1 - Catastrophic Sediment Pulses in the Pokhara Valley, Nepal T1 - Katastrophale Sediment Ablagerungen im Pokhara Tal, Nepal N2 - Fluvial terraces, floodplains, and alluvial fans are the main landforms to store sediments and to decouple hillslopes from eroding mountain rivers. Such low-relief landforms are also preferred locations for humans to settle in otherwise steep and poorly accessible terrain. Abundant water and sediment as essential sources for buildings and infrastructure make these areas amenable places to live at. Yet valley floors are also prone to rare and catastrophic sedimentation that can overload river systems by abruptly increasing the volume of sediment supply, thus causing massive floodplain aggradation, lateral channel instability, and increased flooding. Some valley-fill sediments should thus record these catastrophic sediment pulses, allowing insights into their timing, magnitude, and consequences. This thesis pursues this theme and focuses on a prominent ~150 km2 valley fill in the Pokhara Valley just south of the Annapurna Massif in central Nepal. The Pokhara Valley is conspicuously broad and gentle compared to the surrounding dissected mountain terrain, and is filled with locally more than 70 m of clastic debris. The area’s main river, Seti Khola, descends from the Annapurna Sabche Cirque at 3500-4500 m asl down to 900 m asl where it incises into this valley fill. Humans began to settle on this extensive fan surface in the 1750’s when the Trans-Himalayan trade route connected the Higher Himalayas, passing Pokhara city, with the subtropical lowlands of the Terai. High and unstable river terraces and steep gorges undermined by fast flowing rivers with highly seasonal (monsoon-driven) discharge, a high earthquake risk, and a growing population make the Pokhara Valley an ideal place to study the recent geological and geomorphic history of its sediments and the implication for natural hazard appraisals. The objective of this thesis is to quantify the timing, the sedimentologic and geomorphic processes as well as the fluvial response to a series of strong sediment pulses. I report diagnostic sedimentary archives, lithofacies of the fan terraces, their geochemical provenance, radiocarbon-age dating and the stratigraphic relationship between them. All these various and independent lines of evidence show consistently that multiple sediment pulses filled the Pokhara Valley in medieval times, most likely in connection with, if not triggered by, strong seismic ground shaking. The geomorphic and sedimentary evidence is consistent with catastrophic fluvial aggradation tied to the timing of three medieval Himalayan earthquakes in ~1100, 1255, and 1344 AD. Sediment provenance and calibrated radiocarbon-age data are the key to distinguish three individual sediment pulses, as these are not evident from their sedimentology alone. I explore various measures of adjustment and fluvial response of the river system following these massive aggradation pulses. By using proxies such as net volumetric erosion, incision and erosion rates, clast provenance on active river banks, geomorphic markers such as re-exhumed tree trunks in growth position, and knickpoint locations in tributary valleys, I estimate the response of the river network in the Pokhara Valley to earthquake disturbance over several centuries. Estimates of the removed volumes since catastrophic valley filling began, require average net sediment yields of up to 4200 t km−2 yr−1 since, rates that are consistent with those reported for Himalayan rivers. The lithological composition of active channel-bed load differs from that of local bedrock material, confirming that rivers have adjusted 30-50% depending on data of different tributary catchments, locally incising with rates of 160-220 mm yr−1. In many tributaries to the Seti Khola, most of the contemporary river loads come from a Higher Himalayan source, thus excluding local hillslopes as sources. This imbalance in sediment provenance emphasizes how the medieval sediment pulses must have rapidly traversed up to 70 km downstream to invade the downstream reaches of the tributaries up to 8 km upstream, thereby blocking the local drainage and thus reinforcing, or locally creating new, floodplain lakes still visible in the landscape today. Understanding the formation, origin, mechanism and geomorphic processes of this valley fill is crucial to understand the landscape evolution and response to catastrophic sediment pulses. Several earthquake-triggered long-runout rock-ice avalanches or catastrophic dam burst in the Higher Himalayas are the only plausible mechanisms to explain both the geomorphic and sedimentary legacy that I document here. In any case, the Pokhara Valley was most likely hit by a cascade of extremely rare processes over some two centuries starting in the early 11th century. Nowhere in the Himalayas do we find valley fills of comparable size and equally well documented depositional history, making the Pokhara Valley one of the most extensively dated valley fill in the Himalayas to date. Judging from the growing record of historic Himalayan earthquakes in Nepal that were traced and dated in fault trenches, this thesis shows that sedimentary archives can be used to directly aid reconstructions and predictions of both earthquake triggers and impacts from a sedimentary-response perspective. The knowledge about the timing, evolution, and response of the Pokhara Valley and its river system to earthquake triggered sediment pulses is important to address the seismic and geomorphic risk for the city of Pokhara. This thesis demonstrates how geomorphic evidence on catastrophic valley infill can help to independently verify paleoseismological fault-trench records and may initiate re-thinking on post-seismic hazard assessments in active mountain regions. N2 - Der Transport von Sedimenten in Flüssen ist wichtig, um Landschaftsformen in Gebirgsregionen entstehen zu lassen. Eine erhöhte, plötzliche Sedimentzufuhr, beispielsweise durch Massenbewegungen ausgelöst, kann ein Flusssystem schnell aus dem Gleichgewicht bringen. Innerhalb kurzer Zeit transportiertes Sediment wird häufig an Überschwemmungsflächen abgelagert, was zu instabilen Flussverläufen, erhöhtem Sedimentabtrag und vermehrten Überschwemmungen führen kann. Talverfüllungen, Schwemmmfächer, Flussterrassen und Überschwemmungsebenen sind in diesem Zusammenhang die am häufigsten vorkommenden Landschaftsformen, um große Materialvolumen zu speichern. Weil Wasser und Sediment als Baustoff in ausreichenden Mengen zur Verfügung stehen, sind sie bevorzugte Siedlungsflächen. Diese Dissertation untersucht in drei Studien die Entstehung, geomorphologische und sedimentologische Prozesse, sowie die Anpassung des Flusssystems auf einen erhöhten Sedimenteintrag des heute mit Sedimenten verfüllten Pokhara Tals im zentralen Himalaya. Die Stadt Pokhara liegt am Fuße des bis zu 8000 m hohen Annapurna Massivs auf einem ~150 km2 großen, aus klastischen Sedimentablagerungen bestehender Fächer. Das Tal ist von bis zu 70 m hohen Terrassen gekennzeichnen und auffallend flach im Vergleich zur umliegenden Topographie. Der Seti Khola entwässert das Annapurna Massiv in einer Höhe von 3500-5000 m ü.N.N. und erreicht nach kurzer Distanz den Pokhara Fächer. Erste Bewohner siedelten sich in den 1750er Jahren an als die frühere Handelsroute den Hohen Himalaya mit dem subtropischen Tiefland (Terai) verbunden hat. Seither wächst die Stadt stetig und ist heute, nach Kathmandu, die zweitgrößte Stadt Nepals. Durch die Nähe der geologischen Hauptstörung zwischen dem Hohen Himalaya und dem tiefer liegenden Vorderen Himalaya herrscht ein hohes Erdbebenrisiko im Pokhara Tal. Die Kombination aus hohen Terrassen und tiefen, von schnell fließenden Flüssen ausgespülten Schluchten, machen das Tal zu einem geeigneten Ort, um die kaum untersuchte geologische und geomorphologische Geschichte der in diesem Tal abgelagernten Sedimente zu erforschen. Um Landschaftsveränderungen und -entwicklungen zu verstehen sowie die Reaktion des Flussnetzes auf erhöhte Sedimentzufuhr zu überblicken, ist es unabdingbar, den Ursprung des Materials, die sedimentologischen Prozesse und mögliche Auslöser der Talverfüllung zu analysieren. Daten und Proben aus dem Gelände, die später im Labor datiert, ausgewertet, mit sedimentologischen Aufzeichnungen kombiniert und durch fernerkundliche Methoden ergänzt und analysiert wurden, bilden die Basis der Ergebnisse dieser Dissertation. Da solche massiven, in sehr kurzer Zeit abgelagerten Sedimente auf eine katastrophale Entstehung hindeuten, spielt auch der zeitliche Aspekt eine wichtige Rolle. erschiedene Beweise zeigen, dass mindestens drei Sedimentereignisse das Pokhara Tal verfüllt haben. Ich dokumentiere ein aufschlussreiches Sedimentarchiv, Sedimentabfolgen geochemische Provenienz, Radiokarbonalter und die stratigraphische Beziehung zwischen diesen Ergebnissen. Diese unabhängig voneinander gewonnen Ergebnisse zeigen, dass geomorphologische und sedimentologische Beweise mit den Altersdatierungen konsistent sind und wir mit diesen Untersuchungen die abgelagerten Geröllmassen mit historischen Starkbeben in Verbindung bringen können (~1100, 1255, 1344 AD). Provenienz in Kombination mit den Altersdatierungen lassen uns wiederum die drei Ereignisse in ihren Mächtigkeit unterscheiden und individuel das Volumen bestimmen. Messungen zur Anpassung des Flusssystems ergeben, dass das System noch stark von seinem Gleichgewicht abweicht, da erst 30-70% des über kurze Zeit abgelagerten Materials aus dem Flussbett ausgeräumt wurden. Hierfür benutzte Marker sind unter Anderem volumetrische Berechnungen, Erosionsund Einschneideraten der Flüsse, Bäume in ihrer Wachstumsposition zur Altersdatierung und Stufen im Längsgerinneprofil der Seitenflüsse. Das bis heute abgetragene Volumen ergibt Sedimentaustragsraten von bis zu 4200 t km−2 yr−1 am Fuß des Fächers. Die lithologische Zusammensetzung aktiver Flussbänke in Seitentälern zeigt, dass Material der Formation gegenüber lokalem Grundgestein immer noch dominiert. Dieses lithologische Ungleichgewicht verdeutlicht, wie schnell Sedimentmassen in drei Ereignissen über 70 km talabwärts und bis zu 8 km flussaufwärts (in die Seitentäler) abgelagert wurden. Lokale Einschneideraten in die Pokhara Formation liegen zwischen 0.16-0.22 m yr−1 und weisen auf einen sich schnell verändernden Flussverlauf hin. Um die Landschaftsentwicklung nach solch massiven Sedimentablagerungen analysieren zu können, müssen die Sedimentologie, die geomorphologischen Prozesse, der Ursprung und die Mechanismen der Talverfüllung verstanden und als Basiswissen vorausgesetzt werden. Aus den gewonnen Resultaten schließen wir, dass das Pokhara Tal von mehreren katastrophal aufeinanderfolgenden Naturereignissen in einem Zeitraum von ~200 Jahren seit dem 12. Jahrhundert heimgesucht wurde. Nirgendwo im Himalaya finden wir vergleichbare Talverfüllungen, weder in ihrer Größe, noch in dieser detailliert aufgenommenen geomorphologischen Geschichte und sedimentologischen Aufzeichnungen. Das Pokhara Tals ist damit eine der am besten datierten Talverfüllungen des gesamten Himalaya. Diese Arbeit zeigt, dass in sedimentären Archiven - unabhängig von der Paleoseismologie - historische Starkbeben datiert und erkannt werden können. So hilft das Wissen über den zeitlichen Verlauf der Talverfüllung, die Entwicklung des Fächers und die Anpassung des Flusssystems in Zukunft Entscheidungen zu treffen, die das geomorphologische Risiko für die Stadt Pokhara vermindern und gleichzeitig bauliche Maßnahmen besser an die lokalen Risikofaktoren angepasst werden können. KW - geomorphology KW - geohazards KW - Himalaya KW - radiocarbon age dating KW - Geomorphologie KW - Naturgefahren KW - Himalaya KW - Radiokarbondatierung Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-413341 ER - TY - THES A1 - Rosenwinkel, Swenja T1 - Rock glaciers and natural dams in Central Asia T1 - Blockgletscher und natürliche Staudämme in Zentralasien N2 - The formation and breaching of natural dammed lakes have formed the landscapes, especially in seismically active high-mountain regions. Dammed lakes pose both, potential water resources, and hazard in case of dam breaching. Central Asia has mostly arid and semi-arid climates. Rock glaciers already store more water than ice-glaciers in some semi-arid regions of the world, but their distribution and advance mechanisms are still under debate in recent research. Their impact on the water availability in Central Asia will likely increase as temperatures rise and glaciers diminish. This thesis provides insight to the relative age distribution of selected Kyrgyz and Kazakh rock glaciers and their single lobes derived from lichenometric dating. The size of roughly 8000 different lichen specimens was used to approximate an exposure age of the underlying debris surface. We showed that rock-glacier movement differs signifcantly on small scales. This has several implications for climatic inferences from rock glaciers. First, reactivation of their lobes does not necessarily point to climatic changes, or at least at out-of-equilibrium conditions. Second, the elevations of rock-glacier toes can no longer be considered as general indicators of the limit of sporadic mountain permafrost as they have been used traditionally. In the mountainous and seismically active region of Central Asia, natural dams, besides rock glaciers, also play a key role in controlling water and sediment infux into river valleys. However, rock glaciers advancing into valleys seem to be capable of infuencing the stream network, to dam rivers, or to impound lakes. This influence has not previously been addressed. We quantitatively explored these controls using a new inventory of 1300 Central Asian rock glaciers. Elevation, potential incoming solar radiation, and the size of rock glaciers and their feeder basins played key roles in predicting dam appearance. Bayesian techniques were used to credibly distinguish between lichen sizes on rock glaciers and their lobes, and to find those parameters of a rock-glacier system that are most credibly expressing the potential to build natural dams. To place these studies in the region's history of natural dams, a combination of dating of former lake levels and outburst flood modelling addresses the history and possible outburst flood hypotheses of the second largest mountain lake of the world, Issyk Kul in Kyrgyzstan. Megafoods from breached earthen or glacial dams were found to be a likely explanation for some of the lake's highly fluctuating water levels. However, our detailed analysis of candidate lake sediments and outburst-flood deposits also showed that more localised dam breaks to the west of Issyk Kul could have left similar geomorphic and sedimentary evidence in this Central Asian mountain landscape. We thus caution against readily invoking megafloods as the main cause of lake-level drops of Issyk Kul. In summary, this thesis addresses some new pathways for studying rock glaciers and natural dams with several practical implications for studies on mountain permafrost and natural hazards. N2 - Die Entstehung und das Ausbrechen natürlicher Stauseen prägen die Landschaft, insbesondere in seinsmisch aktiven Hochgebirgsregionen. Stauseen bergen zugleich Potential für Wasserressourcen, aber Gefahr durch Überflutungen. Mit steigenden Temperaturen und voranschreitender Gletscherschmelze wird der Bedarf an alternativen Wasserressourcen steigen. Zentralasien unterliegt größtenteils ariden und semiariden Klimabedingungen. In manchen semiariden Gebieten der Welt speichern Blockgletscher heute schon mehr Wasser als Eisgletscher. Ihr Anteil an der Wasserverfügbarkeit in Zentralasien wird in Zukunft vermutlich steigen. Die Verteilung und die Mechanismen, die das Auftreten und das Vorrücken der Blockgletscher beeinflussen, sind allerdings noch nicht gut erforscht. In der vorliegenden Arbeit wurden Blockgletscher in Kirgistan und Kasachstan ausgewählt, um die Altersverteilung ihrer Loben relativ mit Lichenometrie zu bestimmen. Dafür wurden etwa 8000 Flechtendurchmesser gemessen, die, bei bekannter Wachstumsrate, Aussagen über das Expositionsalter des unterliegenden Gesteins zulassen und somit über die Zeit, seitdem keine Bewegungen mehr stattgefunden haben, die eine andere Seite des Gesteins exponiert hätten. Es zeigte sich, dass die Blockgletscherbewegungen auf kleinräumiger Skala sehr unterschiedlich sind und nicht allein von großräumigen topoklimatischen Gegebenheiten abhängen. Diese Erkenntnis bedeutet eine Einschränkung des in der Literatur häufig gezogenen Rückschlusses von Blockgletscherbewegungen auf klimatische Veränderungen oder der Nutzung von Blockgletscherhöhen als Indikator für die untere Grenze des Permafrostbereiches. Natürliche Staudämme spielen eine Schlüsselrolle dabei den Wasser- und Sedimenteintrag in die Flüsse zu kontrollieren. Blockgletscher können ebenfalls so weit in das Tal vorrücken, dass sie Flussläufe beeinflussen und Seen aufstauen. Diesem Phenomen wurde in dieser Arbeit erstmals nachgegangen und mit einem neu erstellten Inventar von 1300 Blockgletschern die möglichen Kontrollfaktoren, die zu der Bildung eines Blockglestcherdamms führen, ausgewertet. Die Blockgletscherhöhe, die potentielle Sonneneinstrahlung, sowie die Größe der Blockgletscher und ihrer Einzugsgebiete spielen dabei eine große Rolle für die Vorhersage des Auftretens von Blockgletscherdämmen. Für die beiden eben genannten Studien wurde ein Bayesisches Verfahren gewählt, um die mit Hilfe der Größenunterschiede der Flechtendurchmesser auf den einzelnen Blockgletschern und ihren Loben gewonnenen relativen Gesteinsexpositonsaltersunterschiede zu identifizieren. Desweiteren wurde die Methode genutzt, um die Parameter ausfindig zu machen, die am wahrscheinlichsten dazu führen, dass Blockgletscher Dämme bilden. Mit einer Kombination aus Datierungen vergangener Seespiegelstände und Flutmodellierungen möglicher Seeausbrüche des Issyk Kul in Kirgistan, des zweitgrößten Bergsees der Welt, geht diese Arbeit der Plausibilit ät der Zusammenhänge zwischen Seespiegelschwankungen und -ausbrüchen nach, die sich im Quartär zugetragen haben. Dabei wurde ein zeitlicher Zusammenhang zwischen Seespiegelsenkung und Flutablagerungen bestätigt. Die Modellierungen deuten auf groÿe Seeausbrüche hin, zeigen allerdings auch die Möglichkeit auf, dass ein kleinerer aufgestauter See westlich des Issyk Kul auch ähnliche Spuren im Sedimentarchiv hinterlassen haben könnte. Somit sind die Seespiegelabfälle nicht eindeutig katastrophalen Seeausbrüchen zuzuordnen. Zusammenfassend zeigt diese Arbeit neueWege Blockgletscher und natürliche Staudämme zu analysieren und die Ergebnisse liefern praktische Hinweise für die Permafrost- und Naturgefahrenforschung. KW - rock glaciers KW - natural dams KW - natural hazard KW - lichenometry KW - lake-level change KW - cosmogenic nuclide dating KW - Bayes KW - Bayesische Statistik KW - Altersdatierung mit kosmogenen Nukliden KW - Seespiegelschwankungen KW - Lichenometrie KW - Natürliche Staudämme KW - Naturgefahren KW - Blockgletscher Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-410386 ER -