TY - THES A1 - Wagner, Dirk T1 - Microbial perspectives of the methane cycle in permafrost ecosystems in the Eastern Siberian Arctic : implications for the global methane budget N2 - The Arctic plays a key role in Earth’s climate system as global warming is predicted to be most pronounced at high latitudes and because one third of the global carbon pool is stored in ecosystems of the northern latitudes. In order to improve our understanding of the present and future carbon dynamics in climate sensitive permafrost ecosystems, the present study concentrates on investigations of microbial controls of methane fluxes, on the activity and structure of the involved microbial communities, and on their response to changing environmental conditions. For this purpose an integrated research strategy was applied, which connects trace gas flux measurements to soil ecological characterisation of permafrost habitats and molecular ecological analyses of microbial populations. Furthermore, methanogenic archaea isolated from Siberian permafrost have been used as potential keystone organisms for studying and assessing life under extreme living conditions. Long-term studies on methane fluxes were carried out since 1998. These studies revealed considerable seasonal and spatial variations of methane emissions for the different landscape units ranging from 0 to 362 mg m-2 d-1. For the overall balance of methane emissions from the entire delta, the first land cover classification based on Landsat images was performed and applied for an upscaling of the methane flux data sets. The regionally weighted mean daily methane emissions of the Lena Delta (10 mg m-2 d-1) are only one fifth of the values calculated for other Arctic tundra environments. The calculated annual methane emission of the Lena Delta amounts to about 0.03 Tg. The low methane emission rates obtained in this study are the result of the used remotely sensed high-resolution data basis, which provides a more realistic estimation of the real methane emissions on a regional scale. Soil temperature and near soil surface atmospheric turbulence were identified as the driving parameters of methane emissions. A flux model based on these variables explained variations of the methane budget corresponding to continuous processes of microbial methane production and oxidation, and gas diffusion through soil and plants reasonably well. The results show that the Lena Delta contributes significantly to the global methane balance because of its extensive wetland areas. The microbiological investigations showed that permafrost soils are colonized by high numbers of microorganisms. The total biomass is comparable to temperate soil ecosystems. Activities of methanogens and methanotrophs differed significantly in their rates and distribution patterns along both the vertical profiles and the different investigated soils. The methane production rates varied between 0.3 and 38.9 nmol h-1 g-1, while the methane oxidation ranged from 0.2 to 7.0 nmol h-1 g-1. Phylogenetic analyses of methanogenic communities revealed a distinct diversity of methanogens affiliated to Methanomicrobiaceae, Methanosarcinaceae and Methanosaetaceae, which partly form four specific permafrost clusters. The results demonstrate the close relationship between methane fluxes and the fundamental microbiological processes in permafrost soils. The microorganisms do not only survive in their extreme habitat but also can be metabolic active under in situ conditions. It was shown that a slight increase of the temperature can lead to a substantial increase in methanogenic activity within perennially frozen deposits. In case of degradation, this would lead to an extensive expansion of the methane deposits with their subsequent impacts on total methane budget. Further studies on the stress response of methanogenic archaea, especially Methanosarcina SMA-21, isolated from Siberian permafrost, revealed an unexpected resistance of the microorganisms against unfavourable living conditions. A better adaptation to environmental stress was observed at 4 °C compared to 28 °C. For the first time it could be demonstrated that methanogenic archaea from terrestrial permafrost even survived simulated Martian conditions. The results show that permafrost methanogens are more resistant than methanogens from non-permafrost environments under Mars-like climate conditions. Microorganisms comparable to methanogens from terrestrial permafrost can be seen as one of the most likely candidates for life on Mars due to their physiological potential and metabolic specificity. N2 - Die Arktis spielt eine Schlüsselrolle im Klimasystem unserer Erde aus zweierlei Gründen. Zum einen wird vorausgesagt, dass die globale Erwärmung in den hohen Breiten am ausgeprägtesten sein wird. Zum anderen ist ein Drittel des globalen Kohlenstoffs in Ökosystemen der nördlichen Breiten gespeichert. Um ein besseres Verständnis der gegenwärtigen und zukünftigen Entwicklung der Kohlenstoffdynamik in klimaempfindlichen Permafrostökosystemen zu erlangen, konzentriert sich die vorliegende Arbeit auf Untersuchungen zur Kontrolle der Methanflüsse durch Mikroorganismen, auf die Aktivität und Struktur der beteiligten Mikroorganismen-gemeinschaften und auf ihre Reaktion auf sich ändernde Umweltbedingungen. Zu diesem Zweck wurde eine integrierte Forschungsstrategie entwickelt, die Spurengasmessungen mit boden- und molekularökologischen Untersuchungen der Mikroorganismengemeinschaften verknüpft. Langzeitmessungen zu den Methanflüssen werden seit 1998 durchgeführt. Diese Untersuchungen zeigten beträchtliche saisonale und räumliche Schwankungen der Methanemissionen auf, die zwischen 0 und 362 mg m-2 d-1 für die untersuchten Landschaftseinheiten schwankten. Für die Bilanzierung der Methanemissionen für das gesamte Delta wurde erstmals eine Klassifikation der unterschiedlichen Landschaftseinheiten anhand von Landsat-Aufnahmen durchgeführt und für eine Hochrechnung der Methandaten genutzt. Die Mittelwerte der regional gewichteten täglichen Methanemissionen des Lenadeltas (10 mg m-2 d-1) sind nur ein Fünftel so hoch wie die berechneten Werte für andere arktische Tundren. Die errechnete jährliche Methanemission des Lenadeltas beträgt demnach ungefähr 0,03 Tg. Die geringen Methanemissionsraten dieser Studie können durch den bisher noch nicht realisierten integrativen Ansatz, der Langzeitmessungen und Landschafts-klassifizierungen beinhaltet, erklärt werden. Bodentemperatur und oberflächennahe atmosphärische Turbulenzen wurden als die antreibenden Größen der Methanfreisetzung identifiziert. Ein Modell, das auf diesen Variablen basiert, erklärt die Veränderungen der Methanflüsse gemäß der dynamischen mikrobiellen Prozesse und der Diffusion von Methan durch den Boden und die Pflanzen zutreffend. Die Ergebnisse zeigen, dass das Lenadelta erheblich zur globalen Methanemission aufgrund seiner weitreichenden Feuchtgebiete beiträgt. Die mikrobiologischen Untersuchungen zeigten, dass Permafrostböden durch eine hohe Anzahl von Mikroorganismen besiedelt wird. Die Gesamtbiomasse ist dabei mit Bodenökosystemen gemäßigter Klimate vergleichbar. Die Stoffwechselaktivitäten von methanogenen Archaeen und methanotrophen Bakterien unterschieden sich erheblich in ihrer Rate und Verteilung im Tiefenprofil sowie zwischen den verschiedenen untersuchten Böden. Die Methanbildungsrate schwankte dabei zwischen 0,3 und 38,9 nmol h-1 g-1, während die Methanoxidation eine Rate von 0,2 bis 7,0 nmol h-1 g-1 aufwies. Phylogenetische Analysen der methanogenen Mikro-organismengemeinschaften zeigten eine ausgeprägte Diversität der methanogenen Archaeen auf. Die Umweltsequenzen bildeten vier spezifische Permafrostcluster aus, die den Gruppen Methanomicrobiaceae, Methanosarcinaceae und Methano-saetaceae zugeordnet werden konnten. Die Ergebnisse zeigen, dass die Methanfreisetzung durch die zugrunde liegenden mikrobiologischen Prozesse im Permafrostboden gesteuert wird. Die beteiligten Mikroorganismen überleben nicht nur in ihrem extremen Habitat, sondern zeigten auch Stoffwechselaktivität unter in-situ-Bedingungen. Ferner konnte gezeigt werden, dass eine geringfügige Zunahme der Temperatur zu einer erheblichen Zunahme der Methanbildungsaktivität in den ständig gefrorenen Permafrostablagerungen führen kann. Im Falle der Permafrostdegradation würde dieses zu einer gesteigerten Freisetzung von Methan führen mit bisher unbekannten Auswirkungen auf das Gesamtbudget der Methanfreistzung aus arktischen Gebieten. Weitere Untersuchungen zur Stresstoleranz von methanogenen Archaeen – insbesondere des neuen Permafrostisolates Methanosarcina SMA-21 - weisen eine unerwartete Widerstandsfähigkeit der Mikroorganismen gegenüber ungünstigen Lebensbedingungen auf. Eine bessere Anpassung an Umweltstress wurde bei 4°C im Vergleich zu 28°C beobachtet. Zum ersten Mal konnte gezeigt werden, dass methanogene Archaeen aus terrestrischem Permafrost unter simulierten Marsbedingungen unbeschadet überleben. Die Ergebnisse zeigen, dass methanogene Archaeen aus Permafrostböden resistenter gegenüber Umweltstress und Marsbedingungen sind als entsprechende Mikroorganismen aus Habitaten, die nicht durch Permafrost gekennzeichnet sind. Mikroorganismen, die den Archaeen aus terrestrischen Permafrosthabitaten ähneln, können als die wahrscheinlichsten Kandidaten für mögliches Leben auf dem Mars angesehen werden. KW - Methankreislauf KW - mikrobielle Prozesse KW - Diversität KW - Spurengasflüsse KW - Permafrostökosysteme KW - methane cycle KW - microbial processes KW - diversity KW - trace gas fluxes KW - permafrost ecosystems Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-15434 ER - TY - BOOK A1 - Roggan, Alfred A1 - Preßler, Tobias T1 - Das Modell Friedland BT - Vom Zusammenleben deutscher, jüdischer und wendischer Bewohner in einer Niederlausitzer Kleinstadt T3 - Podstupimske pśinoski k Sorabistice = Potsdamer Beiträge zur Sorabistik N2 - Mit dem Band 14 „Das Modell Friedland: Vom Zusammenleben deutscher, jüdischer und wendischer Bewohner in einer Niederlausitzer Kleinstadt“ haben die Herausgeber den Autoren Alfred Roggan und Tobias Preßler die Erweiterung ihrer Forschungen ermöglicht: Widmete sich deren Band 12 „Sorbische/Wendische Spuren in der nördlichen Niederlausitz“ (2019) noch Befunden einer binationalen, weil deutsch-wendischen Geschichte, so wird mit dem Band 14 erstmalig für Ostdeutschland die Dokumentation einer ‚trinationalen‘, also deutsch-jüdisch-wendischen Lebenswelt vorgenommen. Die Untersuchungen verdeutlichen, wie sich drei, im 18. Jahrhundert annähernd gleich große Einwohner-Gruppen, mit ihren Gotteshäusern, ihren Sprachen und einem differenzierten Einwohnerstatus etablierten bzw. arrangiert haben. Es zeigten sich Alleinstellungsmerkmale in Lebens- sowie Kultorganisation, Wirtschaftstätigkeiten und der Kommunikation zwischen den Beheimateten. Mit der Amts-Verwaltung des Johanniter-Ritterordens und dem Stadtrat befanden sie sich in berechenbaren (deutschdominierten) Strukturen. Aus diesem Gefüge und der territorialen Grenzlage zum Kurfürstentum Brandenburg begründeten sich Bedingungen, ohne die es wohl zu keinem „Modell Friedland“ gekommen wäre. Die Autoren sind dankbar, dass sich mit Friedland die gnädige Chance bot, einen Bereich zu untersuchen, in dem Prozesse der wendisch-deutschen Assimilierung in einer eigenen Stetigkeit abliefen, jedoch das Ende jüdischen Lebens auf die Abwanderungen infolge der preußischen Emanzipations-Gesetze des 19. Jahrhunderts und nicht auf die Demütigungen, Verfolgungen sowie dem Völkermord des faschistischen deutschen Staates, zurückzuführen sind. T3 - Podstupimske pśinoski k Sorabistice = Potsdamer Beiträge zur Sorabistik - 14 KW - Brandenburgisch-Niederlausitzische Landesgeschichte KW - Friedland KW - Sorbisch-Deutsch-Jüdische Kulturkontakte Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-525427 SN - 978-3-86956-523-1 SN - 1615-2476 SN - 2192-1016 IS - 14 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Gebel, Arnd A1 - Busch, Aglaja A1 - Stelzel, Christine A1 - Hortobágyi, Tibor A1 - Granacher, Urs T1 - Effects of Physical and Mental Fatigue on Postural Sway and Cortical Activity in Healthy Young Adults JF - Frontiers in Human Neuroscience N2 - Physical fatigue (PF) negatively affects postural control, resulting in impaired balance performance in young and older adults. Similar effects on postural control can be observed for mental fatigue (MF) mainly in older adults. Controversial results exist for young adults. There is a void in the literature on the effects of fatigue on balance and cortical activity. Therefore, this study aimed to examine the acute effects of PF and MF on postural sway and cortical activity. Fifteen healthy young adults aged 28 ± 3 years participated in this study. MF and PF protocols comprising of an all-out repeated sit-to-stand task and a computer-based attention network test, respectively, were applied in random order. Pre and post fatigue, cortical activity and postural sway (i.e., center of pressure displacements [CoPd], velocity [CoPv], and CoP variability [CV CoPd, CV CoPv]) were tested during a challenging bipedal balance board task. Absolute spectral power was calculated for theta (4–7.5 Hz), alpha-2 (10.5–12.5 Hz), beta-1 (13–18 Hz), and beta-2 (18.5–25 Hz) in frontal, central, and parietal regions of interest (ROI) and baseline-normalized. Inference statistics revealed a significant time-by-fatigue interaction for CoPd (p = 0.009, d = 0.39, Δ 9.2%) and CoPv (p = 0.009, d = 0.36, Δ 9.2%), and a significant main effect of time for CoP variability (CV CoPd: p = 0.001, d = 0.84; CV CoPv: p = 0.05, d = 0.62). Post hoc analyses showed a significant increase in CoPd (p = 0.002, d = 1.03) and CoPv (p = 0.003, d = 1.03) following PF but not MF. For cortical activity, a significant time-by-fatigue interaction was found for relative alpha-2 power in parietal (p < 0.001, d = 0.06) areas. Post hoc tests indicated larger alpha-2 power increases after PF (p < 0.001, d = 1.69, Δ 3.9%) compared to MF (p = 0.001, d = 1.03, Δ 2.5%). In addition, changes in parietal alpha-2 power and measures of postural sway did not correlate significantly, irrespective of the applied fatigue protocol. No significant changes were found for the other frequency bands, irrespective of the fatigue protocol and ROI under investigation. Thus, the applied PF protocol resulted in increased postural sway (CoPd and CoPv) and CoP variability accompanied by enhanced alpha-2 power in the parietal ROI while MF led to increased CoP variability and alpha-2 power in our sample of young adults. Potential underlying cortical mechanisms responsible for the greater increase in parietal alpha-2 power after PF were discussed but could not be clearly identified as cause. Therefore, further future research is needed to decipher alternative interpretations. KW - balance KW - cognitive/muscular fatigue KW - EEG KW - theta KW - alpha-2 Y1 - 2022 U6 - https://doi.org/10.3389/fnhum.2022.871930 SN - 1662-5161 VL - 16 SP - 1 EP - 14 PB - Frontiers Media S.A. CY - Lausanne, Schweiz ER - TY - THES A1 - Cruz Lemus, Saul Daniel T1 - Enhancing Efficiency of Inverted Perovskite Solar Cells BT - Employing Carbon Nitride and Poly (Ionic -Liquid)s as Interlayers N2 - Carbon nitride and poly(ionic liquid)s (PILs) have been successfully applied in various fields of materials science owing to their outstanding properties. This thesis aims at the successful application of these polymers as innovative materials in the interfaces of hybrid organic–inorganic perovskite solar cells. A critical problem in harnessing the full thermodynamic potential of halide perovskites in solar cells is the design and modification of interfaces to reduce carrier recombination. Therefore, the interface must be properly studied and improved. This work investigated the effect of applying carbon nitride and PILs on a perovskite surface on the device performance. The facile synthetic method for modifying carbon nitride with vinyl thiazole and barbituric acid (CMB-vTA) yields 2.3 nm layers when solution processing is performed using isopropanol. The nanosheets were applied as a metal-free electron transport layer in inverted perovskite solar cells. The application of carbon nitride layers (CMB-vTA) resulted in negligible current-voltage hysteresis with a high open circuit voltage (Voc) of 1.1 V and a short-circuit current (Jsc) of 20.28 mA cm-2, which afforded efficiencies of up to 17%. Thus, the successful implementation of a carbon nitride-based structure enabled good charge extraction with minimized interface recombination between the perovskite and PCBM. Similarly, PILs represent a new strategy of interfacial modification using an ionic polymer in an n-i-p perovskite architecture.. The application of PILs as an interfacial modifier resulted in solar cell devices with an extraordinarily high efficiency of 21.8% and a Voc of 1.17 V. The implementation reduced non-radiative recombination at the perovskite surface through defect passivation. Finally, our work proposes a novel method to efficiently suppress non-radiative charge recombination using the unexplored properties of carbon nitride and PILs in the solar cell field. Additionally, the method for interfacial modification has general applicability because of the simplicity of the post-treatment approach, and therefore has potential applicability in other solar cells. Thus, this work opens the door to a new class of materials to be implemented. Y1 - 2020 ER - TY - JOUR A1 - Aloui, Ali A1 - Tayech, Amel A1 - Arbi Mejri, Mohamed A1 - Makhlouf, Issam A1 - Clark, Cain C. T. A1 - Granacher, Urs A1 - Zouhal, Hassane A1 - Ben Abderrahman, Abderraouf T1 - Reliability and Validity of a New Taekwondo-Specific Change-of-Direction Speed Test With Striking Techniques in Elite Taekwondo Athletes: A Pilot Study JF - Frontiers in Physiology N2 - The purpose of this study was to examine the test-retest reliability, and convergent and discriminative validity of a new taekwondo-specific change-of-direction (COD) speed test with striking techniques (TST) in elite taekwondo athletes. Twenty (10 males and 10 females) elite (athletes who compete at national level) and top-elite (athletes who compete at national and international level) taekwondo athletes with an average training background of 8.9 ± 1.3 years of systematic taekwondo training participated in this study. During the two-week test-retest period, various generic performance tests measuring COD speed, balance, speed, and jump performance were carried out during the first week and as a retest during the second week. Three TST trials were conducted with each athlete and the best trial was used for further analyses. The relevant performance measure derived from the TST was the time with striking penalty (TST-TSP). TST-TSP performances amounted to 10.57 ± 1.08 s for males and 11.74 ± 1.34 s for females. The reliability analysis of the TST performance was conducted after logarithmic transformation, in order to address the problem of heteroscedasticity. In both groups, the TST demonstrated a high relative test-retest reliability (intraclass correlation coefficients and 90% compatibility limits were 0.80 and 0.47 to 0.93, respectively). For absolute reliability, the TST’s typical error of measurement (TEM), 90% compatibility limits, and magnitudes were 4.6%, 3.4 to 7.7, for males, and 5.4%, 3.9 to 9.0, for females. The homogeneous sample of taekwondo athletes meant that the TST’s TEM exceeded the usual smallest important change (SIC) with 0.2 effect size in the two groups. The new test showed mostly very large correlations with linear sprint speed (r = 0.71 to 0.85) and dynamic balance (r = −0.71 and −0.74), large correlations with COD speed (r = 0.57 to 0.60) and vertical jump performance (r = −0.50 to −0.65), and moderate correlations with horizontal jump performance (r = −0.34 to −0.45) and static balance (r = −0.39 to −0.44). Top-elite athletes showed better TST performances than elite counterparts. Receiver operating characteristic analysis indicated that the TST effectively discriminated between top-elite and elite taekwondo athletes. In conclusion, the TST is a valid, and sensitive test to evaluate the COD speed with taekwondo specific skills, and reliable when considering ICC and TEM. Although the usefulness of the TST is questioned to detect small performance changes in the present population, the TST can detect moderate changes in taekwondo-specific COD speed. KW - taekwondo-specific testing KW - sport-specific performance KW - striking combat sports KW - sensitivity KW - taekwondo electronic scoring system Y1 - 2022 U6 - https://doi.org/10.3389/fphys.2022.774546 SN - 1664-042X VL - 13 SP - 1 EP - 15 PB - Frontiers CY - Lausanne, Schweiz ER - TY - JOUR A1 - Tittel, Jörg A1 - Bork, Rudolf A1 - Röpke, Björn A1 - Geldmacher, Karl A1 - Schnur, Tilo A1 - Faust, Berno A1 - Schaphoff, Sibyll A1 - Dalchow, Claus A1 - Woithe, Franka A1 - Bronstert, Axel A1 - Jeltsch, Florian A1 - Jessel, Beate A1 - Zschalich, Andrea A1 - Rößling, Holger A1 - Spindler, Joris A1 - Gaedke, Ursula A1 - Tielbörger, Katja A1 - Kadmon, R. A1 - Müller, J. A1 - Bissinger, Vera A1 - Weithoff, Guntram A1 - Wallschläger, Hans-Dieter A1 - Wiegleb, Gerhard T1 - Umweltforschung für das Land Brandenburg BT - Projekt Ökologie und Naturschutz / Landschaftsplanung / Landschaftsentwicklung JF - Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam N2 - BISSINGER, V.; TITTEL, J.: Process rates and growth limiting factors of planktonic algae (Chlamydomonas sp.) from extremely acidic (pH 2,5 - 3) mining lakes in Germany ; BORK, H.-R. et al.: Erodierte Autos und Brunnen in Oregon, USA ; BRONSTERT, A. et al.: Bewirtschaftunsmöglichkeiten im Einzugsgebiet der Havel ; JELTSCH, F. et al.: Beweidung als Degradationsfaktor in ariden und semiariden Weidesystemen ; JELTSCH, F. et al.: Entstehung und Bedeutung räumlicher Vegetationsstrukturen in Trockensavannen: Baum-Graskoexistenz und Artenvielfalt ; JESSEL, B. et al.: Bodenbewertung für Planungs- und Zulassungsverfahren in Brandenburg ; JESSEL, B.; ZSCHALICH, A.: Erarbeitung von Ausgleichs- und Ersatzmaßnahmen für die Wert- und Funktionselemente des Landschaftsbildes ; RÖßLING, H. et al.: Umsetzung von Ausgleichs- und Ersatzmaßnahmen beim Ausbau der Bundesautobahn A 9 ; SPINDLER, J.; GAEDKE, U.: Estimating production in plankton food webs from biomass size spectra and allometric relationships ; TIELBÖRGER, K. et al.: Sukzessionsprozesse in einem Sanddünengebiet nach Ausschluß von Beweidung ; TIELBÖRGER, K. et al.: Populationsdynamische Funktionen von Ausbreitung und Dormanz ; TIELBÖRGER, K. et al.: Raum-zeitliche Populationsdynamik von einjährigen Wüstenpflanzen ; TITTEL, J. et al.: Ressourcennutzung und -weitergabe im planktischen Nahrungsnetz eines extrem sauren (pH 2,7) Tagebausees ; WALLSCHLÄGER, D.; WIEGLEB, G.: Offenland-Management auf ehemaligen und in Nutzung befindlichen Truppenübungsplätzen im pleistozänen Flachland Nordostdeutschlands: Naturschutzfachliche Grundlagen und praktische Anwendungen ; WEITHOFF, G.; GAEDKE, U.: Planktische Räuber-Beute-Systeme: Experimentelle Untersuchung von ökologischen Synchronisationen Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3828 SN - 1434-2375 SN - 1611-9339 VL - 8 SP - 80 EP - 134 ER - TY - JOUR A1 - Blumenstein, Oswald A1 - Bronstert, Axel A1 - Günter, A. A1 - Katzenmeier, D. A1 - Friedrich, Sabine A1 - Geldmacher, Karl A1 - Bork, Rudolf A1 - Röpke, Björn A1 - Schaphoff, Sibyll A1 - Schnur, Tilo A1 - Woithe, Franka A1 - Dalchow, Claus A1 - Faust, Berno A1 - Itzerott, Sibylle A1 - Kaden, Klaus A1 - Knösche, Rüdiger T1 - Umweltforschung für das Land Brandenburg BT - Projekt Schutzgüter Wasser, Boden, Luft JF - Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam N2 - BLUMENSTEIN, O.: Investigation of Environmental Quality and Social Structures in a Mining Area in the North West Province of South Africa ; BRONSTERT, A.; GÜNTNER, A.: A large-scale hydrological model for the semi-arid environment of north-eastern Brazil ; BRONSTERT, A. et al.: Hochwasserproblematik und der Zusammenhang mit Landnutzungs- und Klimaänderungen ; FRIEDRICH, S.: Vergleichende Untersuchungen zur Wasserqualität des anfallenden Regenwassers an den 14 Regenwassereinläufen der Stadt Potsdam ; GELDMACHER, K. et al.: Bodenzerstörung im Palouse, Washington, USA ; ITZEROTT, S.; KADEN, K.: Modellierung der flächenhaften Verdunstung im Gebiet der Unteren Havel ; KNÖSCHE, R.: Das remobilisierbare Nährstoffpotential in Augewässersedimenten einer Tieflandflußaue Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3845 SN - 1434-2375 SN - 1611-9339 VL - 8 SP - 136 EP - 173 ER - TY - CHAP A1 - Lück, Erika A1 - Balderjahn, Ingo A1 - Kamm, Birgit A1 - Greil, Holle A1 - Wallschläger, Hans-Dieter A1 - Jessel, Beate A1 - Böckmann, Christine A1 - Oberhänsli, Roland A1 - Soyez, Konrad A1 - Schmeer, Ernst A1 - Blumenstein, Oswald A1 - Berndt, Klaus-Peter A1 - Edeling, Thomas A1 - Friedrich, Sabine A1 - Kaden, Klaus A1 - Scheller, Frieder W. A1 - Petersen, Hans-Georg A1 - Asche, Hartmut A1 - Bronstert, Axel A1 - Giest, Hartmut A1 - Gaedke, Ursula A1 - Löhmannsröben, Hans-Gerd A1 - Jeltsch, Florian A1 - Jänkel, Ralph A1 - Gzik, Axel A1 - Bork, Hans-Rudolf A1 - Bork, Hans-Rudolf T1 - Umweltforschung für das Land Brandenburg : Arbeitsgruppen und Professuren Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3797 ER - TY - JOUR A1 - Jafarnezhadgero, Amir Ali A1 - Noroozi, Raha A1 - Fakhri Mirzanag, Ehsan A1 - Granacher, Urs A1 - de Souza Castelo Oliveira, Anderson T1 - The Impact of COVID-19 and Muscle Fatigue on Cardiorespiratory Fitness and Running Kinetics in Female Recreational Runners JF - Frontiers in Physiology N2 - Background: There is evidence that fully recovered COVID-19 patients usually resume physical exercise, but do not perform at the same intensity level performed prior to infection. The aim of this study was to evaluate the impact of COVID-19 infection and recovery as well as muscle fatigue on cardiorespiratory fitness and running biomechanics in female recreational runners. Methods: Twenty-eight females were divided into a group of hospitalized and recovered COVID-19 patients (COV, n = 14, at least 14 days following recovery) and a group of healthy age-matched controls (CTR, n = 14). Ground reaction forces from stepping on a force plate while barefoot overground running at 3.3 m/s was measured before and after a fatiguing protocol. The fatigue protocol consisted of incrementally increasing running speed until reaching a score of 13 on the 6–20 Borg scale, followed by steady-state running until exhaustion. The effects of group and fatigue were assessed for steady-state running duration, steady-state running speed, ground contact time, vertical instantaneous loading rate and peak propulsion force. Results: COV runners completed only 56% of the running time achieved by the CTR (p < 0.0001), and at a 26% slower steady-state running speed (p < 0.0001). There were fatigue-related reductions in loading rate (p = 0.004) without group differences. Increased ground contact time (p = 0.002) and reduced peak propulsion force (p = 0.005) were found for COV when compared to CTR. Conclusion: Our results suggest that female runners who recovered from COVID-19 showed compromised running endurance and altered running kinetics in the form of longer stance periods and weaker propulsion forces. More research is needed in this area using larger sample sizes to confirm our study findings. KW - hospitalization KW - running mechanics KW - ground reaction forces KW - virus infection KW - COVID-19 Y1 - 2022 U6 - https://doi.org/10.3389/fphys.2022.942589 SN - 1664-042X VL - 13 SP - 1 EP - 10 PB - Frontiers CY - Lausanne, Schweiz ER - TY - JOUR A1 - Granacher, Urs A1 - Nobari, Hadi A1 - Ruivo Alves, Ana A1 - Clemente, Filipe Manuel A1 - Pérez-Gómez, Jorge A1 - Clark, Cain Craig Truman A1 - Zouhal, Hassane T1 - Associations Between Variations in Accumulated Workload and Physiological Variables in Young Male Soccer Players Over the Course of a Season JF - Frontiers in physiology N2 - This study sought to analyze the relationship between in-season training workload with changes in aerobic power (VO2max), maximum and resting heart rate (HRmax and HRrest), linear sprint medium (LSM), and short test (LSS), in soccer players younger than 16 years (under-16 soccer players). We additionally aimed to explain changes in fitness levels during the in-season through regression models, considering accumulated load, baseline levels, and peak height velocity (PHV) as predictors. Twenty-three male sub-elite soccer players aged 15.5 ± 0.2 years (PHV: 13.6 ± 0.4 years; body height: 172.7 ± 4.2 cm; body mass: 61.3 ± 5.6 kg; body fat: 13.7% ± 3.9%; VO2max: 48.4 ± 2.6 mL⋅kg–1⋅min–1), were tested three times across the season (i.e., early-season (EaS), mid-season (MiS), and end-season (EnS) for VO2max, HRmax, LSM, and LSS. Aerobic and speed variables gradually improved over the season and had a strong association with PHV. Moreover, the HRmax demonstrated improvements from EaS to EnS; however, this was more evident in the intermediate period (from EaS to MiS) and had a strong association with VO2max. Regression analysis showed significant predictions for VO2max [F(2, 20) = 8.18, p ≤ 0.001] with an R2 of 0.45. In conclusion, the meaningful variation of youth players’ fitness levels can be observed across the season, and such changes can be partially explained by the load imposed. KW - internal load KW - heart rate KW - linear sprint KW - aerobic power KW - football Y1 - 2021 U6 - https://doi.org/10.3389/fphys.2021.638180 SN - 1664-042X VL - 12 SP - 1 EP - 12 PB - Frontiers Research Foundation CY - Lausanne, Schweiz ER - TY - JOUR A1 - Sariati, Dorsaf A1 - Zouhal, Hassane A1 - Hammami, Raouf A1 - Clark, Cain Craig Truman A1 - Nebigh, Ammar A1 - Chtara, Moktar A1 - Hackney, Anthony C. A1 - Souissi, Nizar A1 - Granacher, Urs A1 - Ben Ounis, Omar T1 - Association Between Mental Imagery and Change of Direction Performance in Young Elite Soccer Players of Different Maturity Status JF - Frontiers in Psychology N2 - Previous studies have not considered the potential influence of maturity status on the relationship between mental imagery and change of direction (CoD) speed in youth soccer. Accordingly, this cross-sectional study examined the association between mental imagery and CoD performance in young elite soccer players of different maturity status. Forty young male soccer players, aged 10-17 years, were assigned into two groups according to their predicted age at peak height velocity (PHV) (Pre-PHV; n = 20 and Post-PHV; n = 20). Participants were evaluated on soccer-specific tests of CoD with (CoDBall-15m) and without (CoD-15m) the ball. Participants completed the movement imagery questionnaire (MIQ) with the three- dimensional structure, internal visual imagery (IVI), external visual imagery (EVI), as well as kinesthetic imagery (KI). The Post-PHV players achieved significantly better results than Pre-PHV in EVI (ES = 1.58, large; p < 0.001), CoD-15m (ES = 2.09, very large; p < 0.001) and CoDBall-15m (ES = 1.60, large; p < 0.001). Correlations were significantly different between maturity groups, where, for the pre-PHV group, a negative very large correlation was observed between CoDBall-15m and KI (r = –0.73, p = 0.001). For the post-PHV group, large negative correlations were observed between CoD-15m and IVI (r = –0.55, p = 0.011), EVI (r = –062, p = 0.003), and KI (r = –0.52, p = 0.020). A large negative correlation of CoDBall-15m with EVI (r = –0.55, p = 0.012) and very large correlation with KI (r = –0.79, p = 0.001) were also observed. This study provides evidence of the theoretical and practical use for the CoD tasks stimulus with imagery. We recommend that sport psychology specialists, coaches, and athletes integrated imagery for CoD tasks in pre-pubertal soccer players to further improve CoD related performance. KW - mental imagery KW - football KW - maturation KW - speed KW - adolescents Y1 - 2021 U6 - https://doi.org/10.3389/fpsyg.2021.665508 SN - 1664-1078 VL - 12 SP - 1 EP - 9 PB - Frontiers Research Foundation CY - Lausanne, Schweiz ER - TY - JOUR A1 - Delfan, Maryam A1 - Juybari, Raheleh Amadeh A1 - Gorgani-Firuzjaee, Sattar A1 - Nielsen, Jens Høiriis A1 - Delfan, Neda A1 - Laher, Ismail A1 - Saeidi, Ayoub A1 - Granacher, Urs A1 - Zouhal, Hassane T1 - High-Intensity Interval Training Improves Cardiac Function by miR-206 Dependent HSP60 Induction in Diabetic Rats JF - Frontiers in Cardiovascular Medicine N2 - Objective: A role for microRNAs is implicated in several biological and pathological processes. We investigated the effects of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on molecular markers of diabetic cardiomyopathy in rats. Methods: Eighteen male Wistar rats (260 ± 10 g; aged 8 weeks) with streptozotocin (STZ)-induced type 1 diabetes mellitus (55 mg/kg, IP) were randomly allocated to three groups: control, MICT, and HIIT. The two different training protocols were performed 5 days each week for 5 weeks. Cardiac performance (end-systolic and end-diastolic dimensions, ejection fraction), the expression of miR-206, HSP60, and markers of apoptosis (cleaved PARP and cytochrome C) were determined at the end of the exercise interventions. Results: Both exercise interventions (HIIT and MICT) decreased blood glucose levels and improved cardiac performance, with greater changes in the HIIT group (p < 0.001, η2: 0.909). While the expressions of miR-206 and apoptotic markers decreased in both training protocols (p < 0.001, η2: 0.967), HIIT caused greater reductions in apoptotic markers and produced a 20% greater reduction in miR-206 compared with the MICT protocol (p < 0.001). Furthermore, both training protocols enhanced the expression of HSP60 (p < 0.001, η2: 0.976), with a nearly 50% greater increase in the HIIT group compared with MICT. Conclusions: Our results indicate that both exercise protocols, HIIT and MICT, have the potential to reduce diabetic cardiomyopathy by modifying the expression of miR-206 and its downstream targets of apoptosis. It seems however that HIIT is even more effective than MICT to modulate these molecular markers. KW - diabetes KW - apoptosis KW - miRNAs KW - exercise KW - cardiomyopathy Y1 - 2022 U6 - https://doi.org/10.3389/fcvm.2022.927956 SN - 2297-055X VL - 9 SP - 1 EP - 11 PB - Frontiers CY - Lausanne, Schweiz ER - TY - JOUR A1 - Gäbler, Martijn A1 - Berberyan, Hermine S. A1 - Prieske, Olaf A1 - Elferink-Gemser, Marije Titia A1 - Hortobágyi, Tibor A1 - Warnke, Torsten A1 - Granacher, Urs T1 - Strength Training Intensity and Volume Affect Performance of Young Kayakers/Canoeists JF - Frontiers in physiology N2 - Purpose: The aim of this study was to compare the effects of moderate intensity, low volume (MILV) vs. low intensity, high volume (LIHV) strength training on sport-specific performance, measures of muscular fitness, and skeletal muscle mass in young kayakers and canoeists. Methods: Semi-elite young kayakers and canoeists (N = 40, 13 ± 0.8 years, 11 girls) performed either MILV (70–80% 1-RM, 6–12 repetitions per set) or LIHV (30–40% 1-RM, 60–120 repetitions per set) strength training for one season. Linear mixed-effects models were used to compare effects of training condition on changes over time in 250 and 2,000 m time trials, handgrip strength, underhand shot throw, average bench pull power over 2 min, and skeletal muscle mass. Both between- and within-subject designs were used for analysis. An alpha of 0.05 was used to determine statistical significance. Results: Between- and within-subject analyses showed that monthly changes were greater in LIHV vs. MILV for the 2,000 m time trial (between: 9.16 s, SE = 2.70, p < 0.01; within: 2,000 m: 13.90 s, SE = 5.02, p = 0.01) and bench pull average power (between: 0.021 W⋅kg–1, SE = 0.008, p = 0.02; within: 0.010 W⋅kg–1, SE = 0.009, p > 0.05). Training conditions did not affect other outcomes. Conclusion: Young sprint kayakers and canoeists benefit from LIHV more than MILV strength training in terms of 2,000 m performance and muscular endurance (i.e., 2 min bench pull power). KW - youth sports KW - water sports KW - exercise test KW - athletic performance KW - anthropometry Y1 - 2021 U6 - https://doi.org/10.3389/fphys.2021.686744 SN - 1664-042X VL - 12 SP - 1 EP - 10 PB - Frontiers Research Foundation CY - Lausanne, Schweiz ER - TY - THES A1 - Herrero Alonso, Yohana T1 - Properties of high-redshift galaxies in different environments T1 - Eigenschaften von Galaxien mit hoher Rotverschiebung in verschiedenen Umgebungen N2 - The Lyman-𝛼 (Ly𝛼) line commonly assists in the detection of high-redshift galaxies, the so-called Lyman-alpha emitters (LAEs). LAEs are useful tools to study the baryonic matter distribution of the high-redshift universe. Exploring their spatial distribution not only reveals the large-scale structure of the universe at early epochs, but it also provides an insight into the early formation and evolution of the galaxies we observe today. Because dark matter halos (DMHs) serve as sites of galaxy formation, the LAE distribution also traces that of the underlying dark matter. However, the details of this relation and their co-evolution over time remain unclear. Moreover, theoretical studies predict that the spatial distribution of LAEs also impacts their own circumgalactic medium (CGM) by influencing their extended Ly𝛼 gaseous halos (LAHs), whose origin is still under investigation. In this thesis, I make several contributions to improve the knowledge on these fields using samples of LAEs observed with the Multi Unit Spectroscopic Explorer (MUSE) at redshifts of 3 < 𝑧 < 6. N2 - Die Lyman-𝛼 (Ly𝛼)-Linie erleichtert die Detektion von Galaxien bei hoher Rotverschiebung, sogenannten den Lyman-Alpha-Emittern (LAEs). Die Erforschung ihrer Verteilung enthüllt nicht nur die großräumige Struktur des Universums in frühen Epochen, sondern bietet auch einen Einblick in die Entstehung und Entwicklung der Galaxien, die wir heute beobachten. Da Halos aus Dunkler Materie (DMHs) als Orte der Galaxienentstehung dienen, spiegelt die LAE-Verteilung auch die der zugrunde liegenden Dunklen Materie wider. Darüber hinaus sagen theoretische Studien voraus, dass die Verteilung von LAEs auch Auswirkungen auf ihr eigenes zirkumgalaktisches Medium (CGM) hat, indem sie ihre ausgedehnten gasförmigen Ly𝛼-Halos (LAHs) beeinflusst. In dieser Dissertation leiste ich mehrere Beiträge zur Verbesserung des Wissens über diese Felder anhand von Stichproben von LAEs, die mit dem Multi Unit Spectroscopic Explorer (MUSE) bei Rotverschiebungen von 3 < 𝑧 < 6 beobachtet wurden. KW - high-redshift KW - Lyman-alpha emitters KW - clustering KW - large-scale structure KW - Lyman-Alpha-Emitter KW - Clustering KW - hoher Rotverschiebung KW - großräumige Struktur des Universums Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-613288 ER - TY - THES A1 - Sarnes-Nitu, Juliane T1 - Mit der Schuldenbremse zu nachhaltigen Staatsfinanzen? T1 - Will the debt brake ensure fiscal sustainability? BT - Wirkungen der neuen Fiskalregel auf die deutschen Bundesländer BT - the new fiscal rule‘s impact on German regional governments N2 - The core question of this paper is: Does the debt brake secure fiscal sustainability in Germany? To answer this question, we will first examine the effects of the introduction of the debt brake on the German federal states in the period 2010-16. For this purpose, the observed consolidation performance and the consolidation incentive or pressure experienced by the federal states were evaluated with the help of a scorecard specifically developed for this purpose. Multiple regression analysis was used to analyze how the scorecard factors affect the consolidation performance of the federal states. It found that nearly 90% of the variation was explained by the independent variables budgetary position, debt burden, revenue growth and pension burden. Thus the debt brake likely played a subordinate role in the 2009-2016 consolidation episode. Subsequently, the data collected in 65 expert interviews was used to analyze the limits of the new fiscal rule, and to determine which potential risks could hinder or prevent the debt brake in the future: municipal debt, FEUs, contingent liabilities in the form of guarantees for financial institutions and pension obligations. The frequently expressed criticism that the debt brake impedes economic growth and public investments is also reviewed and rejected. Finally, we discuss potential future developments regarding the debt brake and the German public administration as well as future consolidation efforts of the Länder. N2 - Die Kernfrage der vorliegenden Arbeit lautet: Sichert die Schuldenbremse die fiskalische Nachhaltigkeit in Deutschland? Zur Beantwortung dieser Frage wird zunächst untersucht, welche Vor-Wirkungen die Einführung der Schuldenbremse im Zeitraum 2010-16 auf die deutschen Bundesländer zeitigte. Dafür wurden die beobachtete Konsolidierungsleistung und der 2009 bestehende Konsolidierungsanreiz bzw. –druck der Bundesländer mit Hilfe einer eigens zu diesem Zweck entwickelten Scorecard evaluiert. Mittels multipler Regressionsanalyse wurde dann analysiert, wie die Faktoren der Scorecard die Konsolidierungsleistung der Bun- desländer beeinflussen. Dabei wurde festgestellt, dass beinahe 90% der Variation, durch die unabhängigen Variablen Haushaltslage, Schuldenlast, Einnahmenwachstum und Pensionslast erklärt werden und der Schuldenbremse bei der Konsolidierungsepisode 2009-2016 eher eine untergeordnete Rolle zugefallen sein dürfte. Anschließend wurde mithilfe der in 65 Expertinneninterviews gesammelten Daten analysiert, welche Grenzen der neuen Fiskalregel in ihrem Wirken gesetzt sind, bzw. welche Risiken zukünftig die Einhaltung der Schuldenbremse erschweren oder verhindern könnten: Kommunalverschuldung, FEUs, Eventualverpflichtungen in Form von Bürgschaften für Finanzinstitute und Pensionsverpflichtungen. Die häufig geäußerten Kritikpunkte, die Schuldenbremse sei eine Konjunktur- und Investitionsbremse werden ebenfalls überprüft und zurückgewiesen. Schließlich werden potentielle zukünftige Entwicklungen hinsichtlich der Schuldenbremse und der öffentlichen Verwaltung in Deutschland sowie der Konsolidierungsbemühungen der Länder erörtert. KW - public finance KW - fiscal rules KW - debt brake KW - rational choice KW - Germany KW - governance KW - consolidation KW - Schuldenbremse KW - Fiskalregeln KW - Deutschland KW - Bundesländer KW - Staatsverschuldung Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-413804 ER - TY - JOUR A1 - Warschburger, Petra A1 - Wortmann, Hanna Rosalie A1 - Gisch, Ulrike Alexandra A1 - Baer, Nadja-Raphaela A1 - Schenk, Liane A1 - Anton, Verena A1 - Bergmann, Manuela M. T1 - An experimental approach to training interoceptive sensitivity BT - study protocol for a pilot randomized controlled trial JF - Nutrition Journal N2 - Background Eating in absence of hunger is quite common and often associated with an increased energy intake co-existent with a poorer food choice. Intuitive eating (IE), i.e., eating in accordance with internal hunger and satiety cues, may protect from overeating. IE, however, requires accurate perception and processing of one’s own bodily signals, also referred to as interoceptive sensitivity. Training interoceptive sensitivity might therefore be an effective method to promote IE and prevent overeating. As most studies on eating behavior are conducted in younger adults and close social relationships influence health-related behavior, this study focuses on middle-aged and older couples. Methods The present pilot randomized intervention study aims at investigating the feasibility and effectiveness of a 21-day mindfulness-based training program designed to increase interoceptive sensitivity. A total of N = 60 couples participating in the NutriAct Family Study, aged 50–80 years, will be recruited. This randomized-controlled intervention study comprises three measurement points (pre-intervention, post-intervention, 4-week follow-up) and a 21-day training that consists of daily mindfulness-based guided audio exercises (e.g., body scan). A three-arm intervention study design is applied to compare two intervention groups (training together as a couple vs. training alone) with a control group (no training). Each measurement point includes the assessment of self-reported and objective indicators of interoceptive sensitivity (primary outcome), self-reported indicators of intuitive and maladaptive eating (secondary outcomes), and additional variables. A training evaluation applying focus group discussions will be conducted to assess participants’ overall acceptance of the training and its feasibility. Discussion By investigating the feasibility and effectiveness of a mindfulness-based training program to increase interoceptive sensitivity, the present study will contribute to a deeper understanding of how to promote healthy eating in older age. KW - Digital intervention KW - Older adults KW - Interoception KW - Eating behavior KW - Intuitive eating KW - Partnership KW - Mindfulness KW - Randomized-controlled trial KW - NutriAct Family Study KW - Mixed methods Y1 - 2022 U6 - https://doi.org/10.1186/s12937-022-00827-4 SN - 1475-2891 VL - 21 PB - Springer Nature CY - London ER - TY - JOUR A1 - Stone, Kate A1 - Nicenboim, Bruno A1 - Vasishth, Shravan A1 - Rösler, Frank T1 - Understanding the effects of constraint and predictability in ERP JF - Neurobiology of language N2 - Intuitively, strongly constraining contexts should lead to stronger probabilistic representations of sentences in memory. Encountering unexpected words could therefore be expected to trigger costlier shifts in these representations than expected words. However, psycholinguistic measures commonly used to study probabilistic processing, such as the N400 event-related potential (ERP) component, are sensitive to word predictability but not to contextual constraint. Some research suggests that constraint-related processing cost may be measurable via an ERP positivity following the N400, known as the anterior post-N400 positivity (PNP). The PNP is argued to reflect update of a sentence representation and to be distinct from the posterior P600, which reflects conflict detection and reanalysis. However, constraint-related PNP findings are inconsistent. We sought to conceptually replicate Federmeier et al. (2007) and Kuperberg et al. (2020), who observed that the PNP, but not the N400 or the P600, was affected by constraint at unexpected but plausible words. Using a pre-registered design and statistical approach maximising power, we demonstrated a dissociated effect of predictability and constraint: strong evidence for predictability but not constraint in the N400 window, and strong evidence for constraint but not predictability in the later window. However, the constraint effect was consistent with a P600 and not a PNP, suggesting increased conflict between a strong representation and unexpected input rather than greater update of the representation. We conclude that either a simple strong/weak constraint design is not always sufficient to elicit the PNP, or that previous PNP constraint findings could be an artifact of smaller sample size. KW - N400 KW - anterior PNP KW - posterior P600 KW - probabilistic processing KW - constraint KW - predictability KW - entropy Y1 - 2022 U6 - https://doi.org/10.1162/nol_a_00094 SN - 2641-4368 VL - 4 IS - 2 SP - 221 EP - 256 PB - MIT Press CY - Cambridge, MA, USA ER - TY - THES A1 - Breitenbach, Sebastian Franz Martin T1 - Changes in monsoonal precipitation and atmospheric circulation during the Holocene reconstructed from stalagmites from Northeastern India T1 - Veränderungen monsunalen Niederschlages und atmosphärischer Zirkulation während des Holozäns, rekonstruiert aus Stalagmiten aus Nordostindien N2 - Recent years witnessed a vast advent of stalagmites as palaeoclimate archives. The multitude of geochemical and physical proxies and a promise of a precise and accurate age model greatly appeal to palaeoclimatologists. Although substantial progress was made in speleothem-based palaeoclimate research and despite high-resolution records from low-latitudinal regions, proving that palaeo-environmental changes can be archived on sub-annual to millennial time scales our comprehension of climate dynamics is still fragmentary. This is in particular true for the summer monsoon system on the Indian subcontinent. The Indian summer monsoon (ISM) is an integral part of the intertropical convergence zone (ITCZ). As this rainfall belt migrates northward during boreal summer, it brings monsoonal rainfall. ISM strength depends however on a variety of factors, including snow cover in Central Asia and oceanic conditions in the Indic and Pacific. Presently, many of the factors influencing the ISM are known, though their exact forcing mechanism and mutual relations remain ambiguous. Attempts to make an accurate prediction of rainfall intensity and frequency and drought recurrence, which is extremely important for South Asian countries, resemble a puzzle game; all interaction need to fall into the right place to obtain a complete picture. My thesis aims to create a faithful picture of climate change in India, covering the last 11,000 ka. NE India represents a key region for the Bay of Bengal (BoB) branch of the ISM, as it is here where the monsoon splits into a northwestward and a northeastward directed arm. The Meghalaya Plateau is the first barrier for northward moving air masses and receives excessive summer rainfall, while the winter season is very dry. The proximity of Meghalaya to the Tibetan Plateau on the one hand and the BoB on the other hand make the study area a key location for investigating the interaction between different forcings that governs the ISM. A basis for the interpretation of palaeoclimate records, and a first important outcome of my thesis is a conceptual model which explains the observed pattern of seasonal changes in stable isotopes (d18O and d2H) in rainfall. I show that although in tropical and subtropical regions the amount effect is commonly called to explain strongly depleted isotope values during enhanced rainfall, alone it cannot account for observed rainwater isotope variability in Meghalaya. Monitoring of rainwater isotopes shows no expected negative correlation between precipitation amount and d18O of rainfall. In turn I find evidence that the runoff from high elevations carries an inherited isotopic signature into the BoB, where during the ISM season the freshwater builds a strongly depleted plume on top of the marine water. The vapor originating from this plume is likely to memorize' and transmit further very negative d18O values. The lack of data does not allow for quantication of this plume effect' on isotopes in rainfall over Meghalaya but I suggest that it varies on seasonal to millennial timescales, depending on the runoff amount and source characteristics. The focal point of my thesis is the extraction of climatic signals archived in stalagmites from NE India. High uranium concentration in the stalagmites ensured excellent age control required for successful high-resolution climate reconstructions. Stable isotope (d18O and d13C) and grey-scale data allow unprecedented insights into millennial to seasonal dynamics of the summer and winter monsoon in NE India. ISM strength (i. e. rainfall amount) is recorded in changes in d18Ostalagmites. The d13C signal, reflecting drip rate changes, renders a powerful proxy for dry season conditions, and shows similarities to temperature-related changes on the Tibetan Plateau. A sub-annual grey-scale profile supports a concept of lower drip rate and slower stalagmite growth during dry conditions. During the Holocene, ISM followed a millennial-scale decrease of insolation, with decadal to centennial failures resulting from atmospheric changes. The period of maximum rainfall and enhanced seasonality corresponds to the Holocene Thermal Optimum observed in Europe. After a phase of rather stable conditions, 4.5 kyr ago, the strengthening ENSO system dominated the ISM. Strong El Nino events weakened the ISM, especially when in concert with positive Indian Ocean dipole events. The strongest droughts of the last 11 kyr are recorded during the past 2 kyr. Using the advantage of a well-dated stalagmite record at hand I tested the application of laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) to detect sub-annual to sub-decadal changes in element concentrations in stalagmites. The development of a large ablation cell allows for ablating sample slabs of up to 22 cm total length. Each analyzed element is a potential proxy for different climatic parameters. Combining my previous results with the LAICP- MS-generated data shows that element concentration depends not only on rainfall amount and associated leaching from the soil. Additional factors, like biological activity and hydrogeochemical conditions in the soil and vadose zone can eventually affect the element content in drip water and in stalagmites. I present a theoretical conceptual model for my study site to explain how climatic signals can be transmitted and archived in stalagmite carbonate. Further, I establish a first 1500 year long element record, reconstructing rainfall variability. Additionally, I hypothesize that volcanic eruptions, producing large amounts of sulfuric acid, can influence soil acidity and hence element mobilization. N2 - Stalagmiten erfuhren in den letzten Jahren vermehrt Aufmerksamkeit als bedeutende Paläoklima- Archive. Paläoklimatologen sind beeindruckt von der grossen Zahl geochemischer und physikalischer Indikatoren (Proxies) und der Möglichkeit, präzise absolute Altersmodelle zu erstellen. Doch obwohl substantielle Fortschritte in der speleothem-basierten Klimaforschung gemacht wurden, und trotz hochaufgelöster Archive aus niederen Breiten, welche zeigen, das Umweltveränderungen auf Zeitskalen von Jahren bis Jahrtausenden archiviert und rekonstruiert werden können, bleibt unser Verständnis der Klimadynamik fragmentarisch. Ganz besonders gilt dies für den Indischen Sommermonsun (ISM) auf dem Indischen Subkontinent. Der ISM ist heute als ein integraler Bestandteil der intertropischen Konvergenzzone verstanden. Sobald dieser Regengürtel während des borealen Sommer nordwärts migriert kann der ISM seine feuchten Luftmassen auf dem Asiatischen Festland entladen. Dabei hängt die Stärke des ISM von einer Vielzahl von Faktoren ab. Zu diesen gehören die Schneedicke in Zentralasien im vorhergehenden Winter und ozeanische Bedingungen im Indischen und Pazifschen Ozean. Heute sind viele dieser Faktoren bekannt. Trotzdem bleiben deren Mechanismen und internen Verbindungen weiterhin mysteriös. Versuche, korrekte Vorhersagen zu Niederschlagsintensität und Häufigkeit oder zu Dürreereignissen zu erstellen ähneln einem Puzzle. All die verschiedenen Interaktionen müssen an die richtige Stelle gelegt werden, um ein sinnvolles Bild entstehen zu lassen. Meine Dissertation versucht, ein vertrauenswürdiges Bild des sich wandelnden Holozänen Klimas in Indien zu erstellen. NE Indien ist eine Schlüsselregion für den östlichen Arm des ISM, da sich hier der ISM in zwei Arme aufteilt, einen nordwestwärts und einen nordostwärts gerichteten. Das Meghalaya Plateau ist das erste Hindernis für die sich nordwärts bewegenden Luftmassen und erhält entsprechend exzessive Niederschläge während des Sommers. Die winterliche Jahreszeit dagegen ist sehr trocken. Die Nähe zum Tibetplateau einerseits und der Bucht von Bengalen andererseits determinieren die Schlüsselposition dieser Region für das Studium der Interaktionen der den ISM beeinflussenden Kräfte. Ein Fundament für die Interpretation der Paläoklimarecords und ein erstes wichtiges Ergebnis meiner Arbeit ist ein konzeptuelles Modell, welches die beobachteten saisonalen Veränderungen stabiler Isotope (d18O und d2H) im Niederschlag erklärt. Ich zeige, das obwohl in tropischen und subtropischen Regionen meist der amount effect zur Erklärung stark negativer Isotopenwerte während starker Niederschläge herangezogen wird, dieser allein nicht ausreicht, um die Isotopenvariabilität im Niederschlag Meghalaya's zu erklären. Die Langzeitbeobachtung der Regenwasserisotopie zeigt keine negative Korrelation zwischen Niederschlagsmenge und d18O. Es finden sich Hinweise, das der Abfluss aus den Hochgebirgsregionen Tibets und des Himalaya eine Isotopensignatur an das Oberflächenwasser der Bucht von Bengalen vererbt. Dort bildet sich aus isotopisch stark abgereicherten Wässern während des ISM eine Süsswasserlinse aus. Es ist wahrscheinlich, das Wasserdampf, der aus dieser Linse stammt, ein Isotopensignal aufgeprägt bekommt, welches abgereichertes d18O weitertransportiert. Der Mangel an Daten lässt es bisher leider nicht zu, quantitative Aussagen über den Einfluss dieses plume effect' auf Niederschläge in Meghalaya zu treffen. Es lässt sich allerdings vermuten, das dieser Einfluss auf saisonalen wie auch auf langen Zeitskalen variabel ist, abhängig vom Abfluss und der Quellencharacteristik. Der Fokus meiner Arbeit liegt in der Herauslösung klimatischer Signale aus nordostindischen Stalagmiten. Hohe Urankonzentrationen in diesen Stalagmiten erlaubt eine exzellente Alterskontrolle, die für hochauflösende Klimarekonstruktionen unerlässlich ist. Die stabilen Isotope (d18O und d13C), sowie Grauwertdaten, erlauben einmalige Einblicke in die Dynamik des Sommer und auch des Wintermonsun in NE Indien. Die ISM Stärke (d. h. Niederschlagsmenge) wird in Veränderungen in den d18Ostalagmites reflektiert. Das d13C Signal, welches Tropfratenänderungen speichert, dient als potenter Indikator für winterliche Trockenheitsbedingungen. Es zeigt Ähnlichkeit zu temperaturabhängigen Veränderungen auf dem Tibetplateau. Das sub-annuell aufgelöste Grauwertprofil stärkt das Konzept, das verminderte Tropfraten und langsameres Stalagmitenwachstum eine Folge von Trockenheit sind. Während des Holozäns folgte der ISM der jahrtausendelangen Verringerung der Insolation. Es finden sich aber ebenso rapide Anomalien, die aus atmosphärischen Veränderungen resultieren. Die Phase des höchsten Niederschlages und erhöhter Saisonalität korrespondiert mit dem Holozänen Thermalen Maximum. Nach einer Phase einigermassen stabilen Bedingungen begann vor ca. 4500 Jahren ENSO einen zunehmenden Einfluss auf den ISM auszuüben. Starke El Nino Ereignisse schwächen den ISM, besonders wenn diese zeitgleich mit positiven Indian Ocean Dipole Ereignissen auftreten. Die stärksten Dürren des gesamten Holozäns traten in den letzten 2000 Jahren auf. Um zusätzliche Informationen aus den hervorragenden Proben zu gewinnen nutzte ich die Vorteile der laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Diese erlaubt die Detektion sub-annueller bis sub-dekadischer Elementkonzentrationsveränderungen in Stalagmiten. Mittels einer neu entwickelten Ablationszelle konnten Proben von maximal 22 cm Länge untersucht werden. Jedes analysierte Element ist ein potentieller Träger einer Klimainformation. Die Kombination der früheren Ergebnisse mit denen der LA-IPC-MS zeigt, das die Elementkonzentrationen nicht nur von Niederschlagsveränderungen und assoziiertem Auswaschen aus dem Boden abhängen. Zusätzlich können auch die biologische Aktivität und hydrogeochemische Bedingungen in der vadosen Zone Einfluss auf die Elementzusammensetzung im Tropfwasser und in den Stalagmiten haben. Darum entwickelte ich ein theoretisches Modell für meinen Standort, um zu klären, wie Klimasignale von der Atmosphäre in die Höhle transportiert werden können. Ein anschliessend rekonstruierter 1500 Jahre langer Proxyrecord zeigt Niederschlagsvariabilität an. Zudem besteht die Möglichkeit, das Vulkaneruptionen, welche grosse Mengen an Schwefelsäure produzieren, eine Bodenversauerung verursachen und damit die Elementmobilisierung verstärken können. KW - Indischer Sommermonsun KW - Stabile Isotope KW - Stalagmiten KW - Holozän KW - Bucht von Bengalen KW - Indian Summer Monsoon KW - Bay of Bengal KW - stable isotopes KW - stalagmites KW - Laser ablation Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-37807 ER - TY - THES A1 - Sieg, Tobias T1 - Reliability of flood damage estimations across spatial scales T1 - Verlässlichkeit von Hochwasserschadensschätzungen über räumliche Skalen N2 - Extreme Naturereignisse sind ein integraler Bestandteil der Natur der Erde. Sie werden erst dann zu Gefahren für die Gesellschaft, wenn sie diesen Ereignissen ausgesetzt ist. Dann allerdings können Naturgefahren verheerende Folgen für die Gesellschaft haben. Besonders hydro-meteorologische Gefahren wie zum Beispiel Flusshochwasser, Starkregenereignisse, Winterstürme, Orkane oder Tornados haben ein hohes Schadenspotential und treten rund um den Globus auf. Einhergehend mit einer immer wärmer werdenden Welt, werden auch Extremwetterereignisse, welche potentiell Naturgefahren auslösen können, immer wahrscheinlicher. Allerdings trägt nicht nur eine sich verändernde Umwelt zur Erhöhung des Risikos von Naturgefahren bei, sondern auch eine sich verändernde Gesellschaft. Daher ist ein angemessenes Risikomanagement erforderlich um die Gesellschaft auf jeder räumlichen Ebene an diese Veränderungen anzupassen. Ein essentieller Bestandteil dieses Managements ist die Abschätzung der ökonomischen Auswirkungen der Naturgefahren. Bisher allerdings fehlen verlässliche Methoden um die Auswirkungen von hydro-meteorologischen Gefahren abzuschätzen. Ein Hauptbestandteil dieser Arbeit ist daher die Entwicklung und Anwendung einer neuen Methode, welche die Verlässlichkeit der Schadensschätzung verbessert. Die Methode wurde beispielhaft zur Schätzung der ökonomischen Auswirkungen eines Flusshochwassers auf einzelne Unternehmen bis hin zu den Auswirkungen auf das gesamte Wirtschaftssystem Deutschlands erfolgreich angewendet. Bestehende Methoden geben meist wenig Information über die Verlässlichkeit ihrer Schätzungen. Da diese Informationen Entscheidungen zur Anpassung an das Risiko erleichtern, wird die Verlässlichkeit der Schadensschätzungen mit der neuen Methode dargestellt. Die Verlässlichkeit bezieht sich dabei nicht nur auf die Schadensschätzung selber, sondern auch auf die Annahmen, die über betroffene Gebäude gemacht werden. Nach diesem Prinzip kann auch die Verlässlichkeit von Annahmen über die Zukunft dargestellt werden, dies ist ein wesentlicher Aspekt für Prognosen. Die Darstellung der Verlässlichkeit und die erfolgreiche Anwendung zeigt das Potential der Methode zur Verwendung von Analysen für gegenwärtige und zukünftige hydro-meteorologische Gefahren. N2 - Natural extreme events are an integral part of nature on planet earth. Usually these events are only considered hazardous to humans, in case they are exposed. In this case, however, natural hazards can have devastating impacts on human societies. Especially hydro-meteorological hazards have a high damage potential in form of e.g. riverine and pluvial floods, winter storms, hurricanes and tornadoes, which can occur all over the globe. Along with an increasingly warm climate also an increase in extreme weather which potentially triggers natural hazards can be expected. Yet, not only changing natural systems, but also changing societal systems contribute to an increasing risk associated with these hazards. These can comprise increasing exposure and possibly also increasing vulnerability to the impacts of natural events. Thus, appropriate risk management is required to adapt all parts of society to existing and upcoming risks at various spatial scales. One essential part of risk management is the risk assessment including the estimation of the economic impacts. However, reliable methods for the estimation of economic impacts due to hydro-meteorological hazards are still missing. Therefore, this thesis deals with the question of how the reliability of hazard damage estimates can be improved, represented and propagated across all spatial scales. This question is investigated using the specific example of economic impacts to companies as a result of riverine floods in Germany. Flood damage models aim to describe the damage processes during a given flood event. In other words they describe the vulnerability of a specific object to a flood. The models can be based on empirical data sets collected after flood events. In this thesis tree-based models trained with survey data are used for the estimation of direct economic flood impacts on the objects. It is found that these machine learning models, in conjunction with increasing sizes of data sets used to derive the models, outperform state-of-the-art damage models. However, despite the performance improvements induced by using multiple variables and more data points, large prediction errors remain at the object level. The occurrence of the high errors was explained by a further investigation using distributions derived from tree-based models. The investigation showed that direct economic impacts to individual objects cannot be modeled by a normal distribution. Yet, most state-of-the-art approaches assume a normal distribution and take mean values as point estimators. Subsequently, the predictions are unlikely values within the distributions resulting in high errors. At larger spatial scales more objects are considered for the damage estimation. This leads to a better fit of the damage estimates to a normal distribution. Consequently, also the performance of the point estimators get better, although large errors can still occur due to the variance of the normal distribution. It is recommended to use distributions instead of point estimates in order to represent the reliability of damage estimates. In addition current approaches also mostly ignore the uncertainty associated with the characteristics of the hazard and the exposed objects. For a given flood event e.g. the estimation of the water level at a certain building is prone to uncertainties. Current approaches define exposed objects mostly by the use of land use data sets. These data sets often show inconsistencies, which introduce additional uncertainties. Furthermore, state-of-the-art approaches also imply problems of missing consistency when predicting the damage at different spatial scales. This is due to the use of different types of exposure data sets for model derivation and application. In order to face these issues a novel object-based method was developed in this thesis. The method enables a seamless estimation of hydro-meteorological hazard damage across spatial scales including uncertainty quantification. The application and validation of the method resulted in plausible estimations at all spatial scales without overestimating the uncertainty. Mainly newly available data sets containing individual buildings make the application of the method possible as they allow for the identification of flood affected objects by overlaying the data sets with water masks. However, the identification of affected objects with two different water masks revealed huge differences in the number of identified objects. Thus, more effort is needed for their identification, since the number of objects affected determines the order of magnitude of the economic flood impacts to a large extent. In general the method represents the uncertainties associated with the three components of risk namely hazard, exposure and vulnerability, in form of probability distributions. The object-based approach enables a consistent propagation of these uncertainties in space. Aside from the propagation of damage estimates and their uncertainties across spatial scales, a propagation between models estimating direct and indirect economic impacts was demonstrated. This enables the inclusion of uncertainties associated with the direct economic impacts within the estimation of the indirect economic impacts. Consequently, the modeling procedure facilitates the representation of the reliability of estimated total economic impacts. The representation of the estimates' reliability prevents reasoning based on a false certainty, which might be attributed to point estimates. Therefore, the developed approach facilitates a meaningful flood risk management and adaptation planning. The successful post-event application and the representation of the uncertainties qualifies the method also for the use for future risk assessments. Thus, the developed method enables the representation of the assumptions made for the future risk assessments, which is crucial information for future risk management. This is an important step forward, since the representation of reliability associated with all components of risk is currently lacking in all state-of-the-art methods assessing future risk. In conclusion, the use of object-based methods giving results in the form of distributions instead of point estimations is recommended. The improvement of the model performance by the means of multi-variable models and additional data points is possible, but small. Uncertainties associated with all components of damage estimation should be included and represented within the results. Furthermore, the findings of the thesis suggest that, at larger scales, the influence of the uncertainty associated with the vulnerability is smaller than those associated with the hazard and exposure. This leads to the conclusion that for an increased reliability of flood damage estimations and risk assessments, the improvement and active inclusion of hazard and exposure, including their uncertainties, is needed in addition to the improvements of the models describing the vulnerability of the objects. KW - hydro-meteorological risk KW - damage modeling KW - uncertainty KW - probabilistic approach KW - economic impacts KW - OpenStreetMap KW - hydro-meteorologische Risiken KW - Schadensmodellierung KW - Unsicherheiten KW - probabilistischer Ansatz KW - ökonomische Auswirkungen KW - OpenStreetMap Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-426161 ER - TY - JOUR A1 - Perkins, Anita A1 - Rose, Andrew A1 - Grossart, Hans-Peter A1 - Rojas-Jimenez, Keilor Osvaldo A1 - Barroso Prescott, Selva Kiri A1 - Oakes, Joanne M. T1 - Oxic and Anoxic Organic Polymer Degradation Potential of Endophytic Fungi From the Marine Macroalga, Ecklonia radiata JF - Frontiers in Microbiology N2 - Cellulose and chitin are the most abundant polymeric, organic carbon source globally. Thus, microbes degrading these polymers significantly influence global carbon cycling and greenhouse gas production. Fungi are recognized as important for cellulose decomposition in terrestrial environments, but are far less studied in marine environments, where bacterial organic matter degradation pathways tend to receive more attention. In this study, we investigated the potential of fungi to degrade kelp detritus, which is a major source of cellulose in marine systems. Given that kelp detritus can be transported considerable distances in the marine environment, we were specifically interested in the capability of endophytic fungi, which are transported with detritus, to ultimately contribute to kelp detritus degradation. We isolated 10 species and two strains of endophytic fungi from the kelp Ecklonia radiata. We then used a dye decolorization assay to assess their ability to degrade organic polymers (lignin, cellulose, and hemicellulose) under both oxic and anoxic conditions and compared their degradation ability with common terrestrial fungi. Under oxic conditions, there was evidence that Ascomycota isolates produced cellulose-degrading extracellular enzymes (associated with manganese peroxidase and sulfur-containing lignin peroxidase), while Mucoromycota isolates appeared to produce both lignin and cellulose-degrading extracellular enzymes, and all Basidiomycota isolates produced lignin-degrading enzymes (associated with laccase and lignin peroxidase). Under anoxic conditions, only three kelp endophytes degraded cellulose. We concluded that kelp fungal endophytes can contribute to cellulose degradation in both oxic and anoxic environments. Thus, endophytic kelp fungi may play a significant role in marine carbon cycling via polymeric organic matter degradation. KW - kelp KW - fungi KW - endophytes KW - carbon cycling KW - extracellular enzymes KW - cellulose polymeric organic matter Y1 - 2021 U6 - https://doi.org/10.3389/fmicb.2021.726138 SN - 1664-302X VL - 12 SP - 1 EP - 13 PB - Frontiers in microbiology CY - Lausanne, Schweiz ER -