TY - JOUR A1 - Zimmermann, Heike Hildegard A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Kruse, Stefan A1 - Müller, Juliane A1 - Stein, Ruediger A1 - Tiedemann, Ralf A1 - Herzschuh, Ulrike T1 - Changes in the composition of marine and sea-ice diatoms derived from sedimentary ancient DNA of the eastern Fram Strait over the past 30 000 years JF - Ocean Science N2 - The Fram Strait is an area with a relatively low and irregular distribution of diatom microfossils in surface sediments, and thus microfossil records are scarce, rarely exceed the Holocene, and contain sparse information about past richness and taxonomic composition. These attributes make the Fram Strait an ideal study site to test the utility of sedimentary ancient DNA (sedaDNA) metabarcoding. Amplifying a short, partial rbcL marker from samples of sediment core MSM05/5-712-2 resulted in 95.7 % of our sequences being assigned to diatoms across 18 different families, with 38.6 % of them being resolved to species and 25.8 % to genus level. Independent replicates show a high similarity of PCR products, especially in the oldest samples. Diatom sedaDNA richness is highest in the Late Weichselian and lowest in Mid- and Late Holocene samples. Taxonomic composition is dominated by cold-water and sea-ice-associated diatoms and suggests several reorganisations – after the Last Glacial Maximum, after the Younger Dryas, and after the Early and after the Mid-Holocene. Different sequences assigned to, amongst others, Chaetoceros socialis indicate the detectability of intra-specific diversity using sedaDNA. We detect no clear pattern between our diatom sedaDNA record and the previously published IP25 record of this core, although proportions of pennate diatoms increase with higher IP25 concentrations and proportions of Nitzschia cf. frigida exceeding 2 % of the assemblage point towards past sea-ice presence. KW - last glacial maximum KW - surface temperatures KW - species composition KW - greenland shelf KW - Disko Bay KW - phytoplankton KW - communities KW - variability KW - diversity KW - Svalbard Y1 - 2019 VL - 16 IS - 5 PB - Springer CY - Tokyo ER - TY - GEN A1 - Zimmermann, Heike Hildegard A1 - Stoof-Leichsenring, Kathleen Rosemarie A1 - Kruse, Stefan A1 - Müller, Juliane A1 - Stein, Ruediger A1 - Tiedemann, Ralf A1 - Herzschuh, Ulrike T1 - Changes in the composition of marine and sea-ice diatoms derived from sedimentary ancient DNA of the eastern Fram Strait over the past 30 000 years T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - The Fram Strait is an area with a relatively low and irregular distribution of diatom microfossils in surface sediments, and thus microfossil records are scarce, rarely exceed the Holocene, and contain sparse information about past richness and taxonomic composition. These attributes make the Fram Strait an ideal study site to test the utility of sedimentary ancient DNA (sedaDNA) metabarcoding. Amplifying a short, partial rbcL marker from samples of sediment core MSM05/5-712-2 resulted in 95.7 % of our sequences being assigned to diatoms across 18 different families, with 38.6 % of them being resolved to species and 25.8 % to genus level. Independent replicates show a high similarity of PCR products, especially in the oldest samples. Diatom sedaDNA richness is highest in the Late Weichselian and lowest in Mid- and Late Holocene samples. Taxonomic composition is dominated by cold-water and sea-ice-associated diatoms and suggests several reorganisations – after the Last Glacial Maximum, after the Younger Dryas, and after the Early and after the Mid-Holocene. Different sequences assigned to, amongst others, Chaetoceros socialis indicate the detectability of intra-specific diversity using sedaDNA. We detect no clear pattern between our diatom sedaDNA record and the previously published IP25 record of this core, although proportions of pennate diatoms increase with higher IP25 concentrations and proportions of Nitzschia cf. frigida exceeding 2 % of the assemblage point towards past sea-ice presence. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1195 KW - last glacial maximum KW - surface temperatures KW - species composition KW - greenland shelf KW - Disko Bay KW - phytoplankton KW - communities KW - variability KW - diversity KW - Svalbard Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-525154 SN - 1866-8372 IS - 5 ER - TY - JOUR A1 - Uygun, Serkan A1 - Clahsen, Harald T1 - Morphological processing in heritage speakers BT - a masked priming study on the Turkish aorist JF - Bilingualism : language and cognition N2 - Previous research has shown that heritage speakers struggle with inflectional morphology. 'Limitations of online resources' for processing a non-dominant language has been claimed as one possible reason for these difficulties. To date, however, there is very little experimental evidence on real-time language processing in heritage speakers. Here we report results from a masked priming experiment with 97 bilingual (Turkish/German) heritage speakers and a control group of 40 non-heritage speakers of Turkish examining regular and irregular forms of the Turkish aorist. We found that, for the regular aorist, heritage speakers use the same morphological decomposition mechanism ('affix stripping') as control speakers, whereas for processing irregularly inflected forms they exhibited more variability (i.e., less homogeneous performance) than the control group. Heritage speakers also demonstrated semantic priming effects. At a more general level, these results indicate that heritage speakers draw on multiple sources of information for recognizing morphologically complex words. KW - Turkish KW - morphology KW - aorist KW - priming KW - variability KW - processing Y1 - 2021 U6 - https://doi.org/10.1017/S1366728920000577 SN - 1366-7289 SN - 1469-1841 VL - 24 IS - 3 SP - 415 EP - 426 PB - Cambridge Univ. Press CY - Cambridge ER - TY - JOUR A1 - Trounson, Karl M. A1 - Busch, Aglaja A1 - Collier, Neil French A1 - Robertson, Samuel T1 - Effects of acute wearable resistance loading on overground running lower body kinematics JF - PLoS one N2 - Field-based sports require athletes to run sub-maximally over significant distances, often while contending with dynamic perturbations to preferred coordination patterns. The ability to adapt movement to maintain performance under such perturbations appears to be trainable through exposure to task variability, which encourages movement variability. The aim of the present study was to investigate the extent to which various wearable resistance loading magnitudes alter coordination and induce movement variability during running. To investigate this, 14 participants (three female and 11 male) performed 10 sub-maximal velocity shuttle runs with either no weight, 1%, 3%, or 5% of body weight attached to the lower limbs. Sagittal plane lower limb joint kinematics from one complete stride cycle in each run were assessed using functional data analysis techniques, both across the participant group and within-individuals. At the group-level, decreases in ankle plantarflexion following toe-off were evident in the 3% and 5% conditions, while increased knee flexion occurred during weight acceptance in the 5% condition compared with unloaded running. At the individual-level, between-run joint angle profiles varied, with six participants exhibiting increased joint angle variability in one or more loading conditions compared with unloaded running. Loading of 5% decreased between-run ankle joint variability among two individuals, likely in accordance with the need to manage increased system load or the novelty of the task. In terms of joint coordination, the most considerable alterations to coordination occurred in the 5% loading condition at the hip-knee joint pair, however, only a minority of participants exhibited this tendency. Coaches should prescribe wearable resistance individually to perturb preferred coordination patterns and encourage movement variability without loading to the extent that movement options become limited. KW - movement patterns KW - external perturbations KW - australian football KW - performance KW - variability KW - coordination KW - freedom KW - leg KW - identification KW - adaptations Y1 - 2020 U6 - https://doi.org/10.1371/journal.pone.0244361 SN - 1932-6203 VL - 15 IS - 12 PB - PLoS CY - San Francisco, California, US ER - TY - GEN A1 - Sunyer, M. A. A1 - Hundecha, Y. A1 - Lawrence, D. A1 - Madsen, H. A1 - Willems, Patrick A1 - Martinkova, M. A1 - Vormoor, Klaus Josef A1 - Bürger, Gerd A1 - Hanel, Martin A1 - Kriaučiūnienė, J. A1 - Loukas, A. A1 - Osuch, M. A1 - Yücel, I. T1 - Inter-comparison of statistical downscaling methods for projection of extreme precipitation in Europe T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Information on extreme precipitation for future climate is needed to assess the changes in the frequency and intensity of flooding. The primary source of information in climate change impact studies is climate model projections. However, due to the coarse resolution and biases of these models, they cannot be directly used in hydrological models. Hence, statistical downscaling is necessary to address climate change impacts at the catchment scale. This study compares eight statistical downscaling methods (SDMs) often used in climate change impact studies. Four methods are based on change factors (CFs), three are bias correction (BC) methods, and one is a perfect prognosis method. The eight methods are used to downscale precipitation output from 15 regional climate models (RCMs) from the ENSEMBLES project for 11 catchments in Europe. The overall results point to an increase in extreme precipitation in most catchments in both winter and summer. For individual catchments, the downscaled time series tend to agree on the direction of the change but differ in the magnitude. Differences between the SDMs vary between the catchments and depend on the season analysed. Similarly, general conclusions cannot be drawn regarding the differences between CFs and BC methods. The performance of the BC methods during the control period also depends on the catchment, but in most cases they represent an improvement compared to RCM outputs. Analysis of the variance in the ensemble of RCMs and SDMs indicates that at least 30% and up to approximately half of the total variance is derived from the SDMs. This study illustrates the large variability in the expected changes in extreme precipitation and highlights the need for considering an ensemble of both SDMs and climate models. Recommendations are provided for the selection of the most suitable SDMs to include in the analysis. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 512 KW - climate-change impacts KW - model output KW - assessing uncertainties KW - multimodel ensemble KW - bias correction KW - simulations KW - scenarios KW - variability KW - basin KW - UK Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-408920 SN - 1866-8372 IS - 512 ER - TY - JOUR A1 - Seifert, Linda I. A1 - Weithoff, Guntram A1 - Vos, Matthijs T1 - Extreme heat changes post-heat wave community reassembly JF - Ecology and evolution N2 - Climate forecasts project further increases in extremely high-temperature events. These present threats to biodiversity, as they promote population declines and local species extinctions. This implies that ecological communities will need to rely more strongly on recovery processes, such as recolonization from a meta-community context. It is poorly understood how differences in extreme event intensity change the outcome of subsequent community reassembly and if such extremes modify the biotic environment in ways that would prevent the successful re-establishment of lost species. We studied replicated aquatic communities consisting of algae and herbivorous rotifers in a design that involved a control and two different heat wave intensity treatments (29 degrees C and 39 degrees C). Animal species that suffered heat-induced extinction were subsequently re-introduced at the same time and density, in each of the two treatments. The 39 degrees C treatment led to community closure in all replicates, meaning that a previously successful herbivore species could not re-establish itself in the postheat wave community. In contrast, such closure never occurred after a 29 degrees C event. Heat wave intensity determined the number of herbivore extinctions and strongly affected algal relative abundances. Re-introduced herbivore species were thus confronted with significantly different food environments. This ecological legacy generated by heat wave intensity led to differences in the failure or success of herbivore species re-introductions. Reassembly was significantly more variable, and hence less predictable, after an extreme heat wave, and was more canalized after a moderate one. Our results pertain to relatively simple communities, but they suggest that ecological legacies introduced by extremely high-temperature events may change subsequent ecological recovery and even prevent the successful re-establishment of lost species. Knowing the processes promoting and preventing ecological recovery is crucial to the success of species re-introduction programs and to our ability to restore ecosystems damaged by environmental extremes. KW - Biodiversity KW - climate change KW - conservation KW - ecological restoration KW - extinction KW - extreme temperature events KW - global warming KW - maximum temperature KW - variability Y1 - 2015 U6 - https://doi.org/10.1002/ece3.1490 SN - 2045-7758 VL - 5 IS - 11 SP - 2140 EP - 2148 PB - Wiley-Blackwell CY - Hoboken ER - TY - GEN A1 - Seibert, Mathias A1 - Merz, Bruno A1 - Apel, Heiko T1 - Seasonal forecasting of hydrological drought in the Limpopo Basin BT - a comparison of statistical methods T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - The Limpopo Basin in southern Africa is prone to droughts which affect the livelihood of millions of people in South Africa, Botswana, Zimbabwe and Mozambique. Seasonal drought early warning is thus vital for the whole region. In this study, the predictability of hydrological droughts during the main runoff period from December to May is assessed using statistical approaches. Three methods (multiple linear models, artificial neural networks, random forest regression trees) are compared in terms of their ability to forecast streamflow with up to 12 months of lead time. The following four main findings result from the study. 1. There are stations in the basin at which standardised streamflow is predictable with lead times up to 12 months. The results show high inter-station differences of forecast skill but reach a coefficient of determination as high as 0.73 (cross validated). 2. A large range of potential predictors is considered in this study, comprising well-established climate indices, customised teleconnection indices derived from sea surface temperatures and antecedent streamflow as a proxy of catchment conditions. El Nino and customised indices, representing sea surface temperature in the Atlantic and Indian oceans, prove to be important teleconnection predictors for the region. Antecedent streamflow is a strong predictor in small catchments (with median 42% explained variance), whereas teleconnections exert a stronger influence in large catchments. 3. Multiple linear models show the best forecast skill in this study and the greatest robustness compared to artificial neural networks and random forest regression trees, despite their capabilities to represent nonlinear relationships. 4. Employed in early warning, the models can be used to forecast a specific drought level. Even if the coefficient of determination is low, the forecast models have a skill better than a climatological forecast, which is shown by analysis of receiver operating characteristics (ROCs). Seasonal statistical forecasts in the Limpopo show promising results, and thus it is recommended to employ them as complementary to existing forecasts in order to strengthen preparedness for droughts. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 626 KW - sea-surface temperature KW - southern Africa KW - neural-network KW - summer rainfall KW - Atlantic-Ocean KW - river-basin KW - predictability KW - variability KW - prediction KW - climate Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-418442 IS - 626 SP - 1611 EP - 1629 ER - TY - JOUR A1 - Schmidt, Silke Regina A1 - Gerten, Dieter A1 - Hintze, Thomas A1 - Lischeid, Gunnar A1 - Livingstone, David M. A1 - Adrian, Rita T1 - Temporal and spatial scales of water temperature variability as an indicator for mixing in a polymictic lake JF - Inland waters : journal of the International Society of Limnology N2 - We applied coarse spectral analysis to more than 2 decades of daily near-surface water temperature (WT) measurements from Muggelsee, a shallow polymictic lake in Germany, to systematically characterize patterns in WT variability from daily to yearly temporal scales. Comparison of WT with local air temperature indicates that the WT variability patterns are likely attributable to both meteorological forcing and internal lake dynamics. We identified seasonal patterns of WT variability and showed that WT variability increases with increasing Schmidt stability, decreasing Lake number and decreasing ice cover duration, and is higher near the shore than in open water. We introduced the slope of WT spectra as an indicator for the degree of lake mixing to help explain the identified temporal and spatial scales of WT variability. The explanatory power of this indicator in other lakes with different mixing regimes remains to be established. KW - Lake number KW - polymictic lakes KW - Schmidt stability KW - seasonality KW - spectral analysis KW - variability Y1 - 2018 U6 - https://doi.org/10.1080/20442041.2018.1429067 SN - 2044-2041 SN - 2044-205X VL - 8 IS - 1 SP - 82 EP - 95 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - THES A1 - Schmidt, Silke Regina T1 - Analyzing lakes in the time frequency domain T1 - Analyse von Seen in der Zeit-Frequenz-Domäne N2 - The central aim of this thesis is to demonstrate the benefits of innovative frequency-based methods to better explain the variability observed in lake ecosystems. Freshwater ecosystems may be the most threatened part of the hydrosphere. Lake ecosystems are particularly sensitive to changes in climate and land use because they integrate disturbances across their entire catchment. This makes understanding the dynamics of lake ecosystems an intriguing and important research priority. This thesis adds new findings to the baseline knowledge regarding variability in lake ecosystems. It provides a literature-based, data-driven and methodological framework for the investigation of variability and patterns in environmental parameters in the time frequency domain. Observational data often show considerable variability in the environmental parameters of lake ecosystems. This variability is mostly driven by a plethora of periodic and stochastic processes inside and outside the ecosystems. These run in parallel and may operate at vastly different time scales, ranging from seconds to decades. In measured data, all of these signals are superimposed, and dominant processes may obscure the signals of other processes, particularly when analyzing mean values over long time scales. Dominant signals are often caused by phenomena at long time scales like seasonal cycles, and most of these are well understood in the limnological literature. The variability injected by biological, chemical and physical processes operating at smaller time scales is less well understood. However, variability affects the state and health of lake ecosystems at all time scales. Besides measuring time series at sufficiently high temporal resolution, the investigation of the full spectrum of variability requires innovative methods of analysis. Analyzing observational data in the time frequency domain allows to identify variability at different time scales and facilitates their attribution to specific processes. The merit of this approach is subsequently demonstrated in three case studies. The first study uses a conceptual analysis to demonstrate the importance of time scales for the detection of ecosystem responses to climate change. These responses often occur during critical time windows in the year, may exhibit a time lag and can be driven by the exceedance of thresholds in their drivers. This can only be detected if the temporal resolution of the data is high enough. The second study applies Fast Fourier Transform spectral analysis to two decades of daily water temperature measurements to show how temporal and spatial scales of water temperature variability can serve as an indicator for mixing in a shallow, polymictic lake. The final study uses wavelet coherence as a diagnostic tool for limnology on a multivariate high-frequency data set recorded between the onset of ice cover and a cyanobacteria summer bloom in the year 2009 in a polymictic lake. Synchronicities among limnological and meteorological time series in narrow frequency bands were used to identify and disentangle prevailing limnological processes. Beyond the novel empirical findings reported in the three case studies, this thesis aims to more generally be of interest to researchers dealing with now increasingly available time series data at high temporal resolution. A set of innovative methods to attribute patterns to processes, their drivers and constraints is provided to help make more efficient use of this kind of data. N2 - See-Ökosysteme sind eine der bedrohtesten Ressourcen der Hydrosphäre. Sie reagieren besonders sensibel auf Veränderungen des Klimas und auf Einflüsse durch Landnutzung, da verschiedene Prozesse im gesamten Einzugsgebiet auf sie einwirken. Daher ist es von besonderer Dringlichkeit, die verschiedenen Prozess-Dynamiken in See-Ökosystemen besser zu verstehen. Die hier vorliegende Doktorarbeit hat zum Ziel, das bestehende Wissen bezüglich der verschiedenen einwirkenden Prozesse in See-Ökosystemen zu erweitern. Die Arbeit stellt ein Forschungsdesign zur Diskussion, das eine Literatur-basierte und auf empirischen Erhebungen beruhende Analyse von Variabilität und Mustern in großen Datensätzen verschiedener Umweltparameter im Zeit-Frequenz-Raum ermöglicht. Umweltparameter sind häufig charakterisiert durch eine hohe zeitliche Dynamik. Diese Variabilität steht im Zentrum dieser Arbeit. Sie wird durch eine Fülle an periodischen und stochastischen Prozessen innerhalb und außerhalb des Ökosystems getrieben. Diese Prozesse können gleichzeitig und auf sehr unterschiedlichen Zeitskalen, von Sekunden bis hin zu Dekaden, ablaufen. In Messdaten überlagern sich alle diese Signale, und dominante Prozesse können die Signale anderer Prozesse verschleiern, insbesondere wenn Mittelwerte über längere Zeiträume analysiert werden. Dominante Signale werden oft durch Prozesse auf längeren Zeitskalen verursacht, wie z. B. saisonale Zyklen. Diese sind im Allgemeinen in der limnologischen Literatur gut dokumentiert. See-Ökosysteme werden allerdings von Prozessen auf allen Zeitskalen beeinflusst. Insbesondere biologische, chemische und physikalische Prozesse operieren in kürzeren Zeitrahmen. Die Variabilität, die über solche Prozesse in See-Ökosysteme eingebracht wird, ist bisher weit weniger gut erforscht. Neben der Notwendigkeit, Umweltparameter in hoher zeitlicher Auflösung zu messen, erfordert die Untersuchung der kompletten Bandbreite an Variabilität innovative Analysemethoden. Die Berücksichtigung der Zeit-Frequenz-Domäne kann dabei helfen, Dynamiken auf verschiedenen Zeitskalen zu identifizieren und daraus bestimmte Prozesse abzuleiten. Diese Arbeit zeigt die Vorzüge dieser Herangehensweise anhand von drei Fallstudien auf. Die erste Studie zeigt die Bedeutung von Zeitskalen für die Erfassung von Ökosystem-Reaktionen auf klimatische Veränderungen. Diese ereignen sich oft während kritischer Zeitfenster im Jahresverlauf und können durch die Überschreitung von Schwellenwerten in den treibenden Variablen, unter Umständen zeitlich verzögert, verursacht sein. Solche Zusammenhänge können nur erfasst werden, wenn die zeitliche Auflösung der Daten hoch genug ist. In der zweiten Studie wird die Spektralanalyse, basierend auf der Fast Fourier Transformation, auf einen Datensatz täglicher Messungen der Wassertemperatur über zwanzig Jahre hinweg angewendet. Es wird gezeigt, wie zeitliche und räumliche Skalen der Variabilität der Wassertemperatur als Indikator für Mischprozesse in einem polymiktischen See dienen können. In der dritten Studie wird die Wavelet Coherence als Diagnose-Werkzeug für einen multivariaten, hochfrequenten Datensatz genutzt. Dieser wurde zwischen dem Einsetzen einer Eisbedeckung und einer Sommerblüte von Cyanobakteriern in einem polymiktischen See im Jahr 2009 erhoben. Synchronizitäten zwischen limnologischen und meteorologischen Zeitreihen in schmalen Frequenz-Bändern wurden genutzt, um vorherrschende limnologische Prozesse zu identifizieren und analytisch zu trennen. Neben den neuen empirischen Erkenntnissen, die in den drei Fallstudien präsentiert werden, zielt diese Doktorarbeit darauf ab, Forscher*innen, Behörden und politischen Entscheidungsträger*innen eine Grundlage zu liefern, die hohe zeitliche Auflösung der heute vielfach verfügbaren Monitoring-Datensätze effizienter zu nutzen. Innovative Methoden sollen dabei helfen, Muster in den Daten Prozessen zuzuordnen und die entsprechenden Treiber und Limitationen zu identifizieren. KW - variability KW - time scale KW - wavelet KW - coherence KW - spectral analysis KW - time series analysis KW - polymictic lakes KW - process identification KW - Variabilität KW - Zeitskala KW - Spektralanalyse KW - Zeitreihenanalyse KW - polymiktische Seen KW - Prozessidentifikation Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-406955 ER - TY - JOUR A1 - Scharhag-Rosenberger, Friederike A1 - Walitzek, Susanne A1 - Kindermann, Wilfried A1 - Meyer, Tim T1 - Differences in adaptations to 1 year of aerobic endurance training individual patterns of nonresponse JF - Scandinavian journal of medicine & science in sports N2 - Lacking responses to endurance training (ET) have been observed for several variables. However, detailed analyses of individuals' responses are scarce. To learn more about the variability of ET adaptations, patterns of response were analyzed for each subject in a 1-year ET study. Eighteen participants [42 +/- 5 years, body mass index: 24 +/- 3 kg/m2, maximal oxygen uptake (VO2max): 38 +/- 5 mL/min/kg] completed a 1-year jogging/walking program on 3 days/week, 45 min/session at 60% heart rate (HR) reserve. VO2max, resting HR (rHR), exercise HR (eHR) and individual anaerobic threshold (IAT) were determined by treadmill and cycling ergometry respectively. Intraindividual coefficients of variation were extracted from the literature to distinguish random changes from training responses. Eight participants showed improvements in all variables. In 10 participants, one or two variables did not improve (VO2max, rHR, eHR and IAT remained unchanged in four, four, three and one cases, respectively). At least one variable improved in each subject. Data indicate that ET adaptations might be detected in each individual using multiple variables of different adaptation levels and intensity domains. Nonresponse seems to occur frequently and might affect all variables. Further studies should investigate whether nonresponders improve with altered training. Furthermore, associations between patterns of nonresponse and health benefits from ET are worth considering. KW - variability KW - responder KW - nonresponder Y1 - 2012 U6 - https://doi.org/10.1111/j.1600-0838.2010.01139.x SN - 0905-7188 VL - 22 IS - 1 SP - 113 EP - 118 PB - Wiley-Blackwell CY - Malden ER - TY - GEN A1 - Schaefer, Laura A1 - Bittmann, Frank T1 - Mechanotendography in Achillodynia shows reduced oscillation variability of pre-loaded Achilles tendon BT - a pilot study T2 - Postprints der Universität Potsdam : Humanwissenschaftliche Reihe N2 - The present study focuses on an innovative approach in measuring the mechanical oscillations of pre-loaded Achilles tendon by using Mechanotendography (MTG) during application of a short yet powerful mechanical pressure impact. This was applied on the forefoot from the plantar side in direction of dorsiflexion, while the subject stood on the ball of the forefoot on one leg. Participants with Achilles tendinopathy (AT; n = 10) were compared to healthy controls (Con; n = 10). Five trials were performed on each side of the body. For evaluation, two intervals after the impulse began (0-100ms; 30-100ms) were cut from the MTG and pressure raw signals. The intrapersonal variability between the five trials in both intervals were evaluated using the arithmetic mean and coefficient of variation of the mean correlation (Spearman rank correlation) and the normalized averaged mean distances, respectively. The AT-group showed a significantly reduced variability in MTG compared to the Con-group (from p = 0.006 to p = 0.028 for different parameters). The 95% confidence intervals (CI) of MTG results were disjoint, whereas the 95% CIs of the pressure signals were similar (p = 0.192 to p = 0.601). We suggest from this work that the variability of mechanical tendon oscillations could be an indicative parameter of an altered Achilles tendon functionality. T3 - Zweitveröffentlichungen der Universität Potsdam : Humanwissenschaftliche Reihe - 668 KW - Mechanotendography KW - mechanical tendinous oscillations KW - variability KW - impact on pre-activated Achilles tendon Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-483499 SN - 1866-8364 IS - 668 ER - TY - JOUR A1 - Schaefer, Laura A1 - Bittmann, Frank T1 - Mechanotendography in Achillodynia shows reduced oscillation variability of pre-loaded Achilles tendon BT - a pilot study JF - European Journal of Translational Myology (EJTM) N2 - The present study focuses on an innovative approach in measuring the mechanical oscillations of pre-loaded Achilles tendon by using Mechanotendography (MTG) during application of a short yet powerful mechanical pressure impact. This was applied on the forefoot from the plantar side in direction of dorsiflexion, while the subject stood on the ball of the forefoot on one leg. Participants with Achilles tendinopathy (AT; n = 10) were compared to healthy controls (Con; n = 10). Five trials were performed on each side of the body. For evaluation, two intervals after the impulse began (0-100ms; 30-100ms) were cut from the MTG and pressure raw signals. The intrapersonal variability between the five trials in both intervals were evaluated using the arithmetic mean and coefficient of variation of the mean correlation (Spearman rank correlation) and the normalized averaged mean distances, respectively. The AT-group showed a significantly reduced variability in MTG compared to the Con-group (from p = 0.006 to p = 0.028 for different parameters). The 95% confidence intervals (CI) of MTG results were disjoint, whereas the 95% CIs of the pressure signals were similar (p = 0.192 to p = 0.601). We suggest from this work that the variability of mechanical tendon oscillations could be an indicative parameter of an altered Achilles tendon functionality. KW - Mechanotendography KW - mechanical tendinous oscillations KW - variability KW - impact on pre-activated Achilles tendon Y1 - 2020 U6 - https://doi.org/10.4081/ejtm.2020.8983 SN - 2037-7460 VL - 30 IS - 2 SP - 247 EP - 257 PB - Unipress CY - Padova ER - TY - THES A1 - Schaber, Jörg T1 - Phenology in Germany in the 20th century : methods, analyses and models N2 - Die Länge der Vegetationsperiode (VP) spielt eine zentrale Rolle für die interannuelle Variation der Kohlenstoffspeicherung terrestrischer Ökosysteme. Die Analyse von Beobachtungsdaten hat gezeigt, dass sich die VP in den letzten Jahrzehnten in den nördlichen Breiten verlängert hat. Dieses Phänomen wurde oft im Zusammenhang mit der globalen Erwärmung diskutiert, da die Phänologie von der Temperatur beeinflusst wird. Die Analyse der Pflanzenphänologie in Süddeutschland im 20. Jahrhundert zeigte: - Die starke Verfrühung der Frühjahrsphasen in dem Jahrzehnt vor 1999 war kein singuläres Ereignis im 20. Jahrhundert. Schon in früheren Dekaden gab es ähnliche Trends. Es konnten Perioden mit unterschiedlichem Trendverhalten identifiziert werden. - Es gab deutliche Unterschiede in den Trends von frühen und späten Frühjahrsphasen. Die frühen Frühjahrsphasen haben sich stetig verfrüht, mit deutlicher Verfrühung zwischen 1931 und 1948, moderater Verfrühung zwischen 1948 und 1984 und starker Verfrühung zwischen 1984 und 1999. Die späten Frühjahrsphasen hingegen, wechselten ihr Trendverhalten in diesen Perioden von einer Verfrühung zu einer deutlichen Verspätung wieder zu einer starken Verfrühung. Dieser Unterschied in der Trendentwicklung zwischen frühen und späten Frühjahrsphasen konnte auch für ganz Deutschland in den Perioden 1951 bis 1984 und 1984 bis 1999 beobachtet werden. Der bestimmende Einfluss der Temperatur auf die Frühjahrsphasen und ihr modifizierender Einfluss auf die Herbstphasen konnte bestätigt werden. Es zeigt sich jedoch, dass - die Phänologie bestimmende Funktionen der Temperatur nicht mit einem globalen jährlichen CO2 Signal korreliert waren, welches als Index für die globale Erwärmung verwendet wurde - ein Index für grossräumige regionale Zirkulationsmuster (NAO-Index) nur zu einem kleinen Teil die beobachtete phänologischen Variabilität erklären konnte. Das beobachtete unterschiedliche Trendverhalten zwischen frühen und späten Frühjahrsphasen konnte auf die unterschiedliche Entwicklung von März- und Apriltemperaturen zurückgeführt werden. Während sich die Märztemperaturen im Laufe des 20. Jahrhunderts mit einer zunehmenden Variabilität in den letzten 50 Jahren stetig erhöht haben, haben sich die Apriltemperaturen zwischen dem Ende der 1940er und Mitte der 1980er merklich abgekühlt und dann wieder deutlich erwärmt. Es wurde geschlussfolgert, dass die Verfrühungen in der Frühjahrsphänologie in den letzten Dekaden Teile multi-dekadischer Fluktuationen sind, welche sich nach Spezies und relevanter saisonaler Temperatur unterscheiden. Aufgrund dieser Fluktuationen konnte kein Zusammenhang mit einem globalen Erwärmungsignal gefunden werden. Im Durchschnitt haben sich alle betrachteten Frühjahrsphasen zwischen 1951 und 1999 in Naturräumen in Deutschland zwischen 5 und 20 Tagen verfrüht. Ein starker Unterschied in der Verfrühung zwischen frühen und späten Frühjahrsphasen liegt an deren erwähntem unterschiedlichen Verhalten. Die Blattverfärbung hat sich zwischen 1951 und 1999 für alle Spezies verspätet, aber nach 1984 im Durchschnitt verfrüht. Die VP hat sich in Deutschland zwischen 1951 und 1999 um ca. 10 Tage verlängert. Es ist hauptsächlich die Änderung in den Frühjahrphasen, die zu einer Änderung in der potentiell absorbierten Strahlung (PAS) führt. Darüber hinaus sind es die späten Frühjahrsphasen, die pro Tag Verfrühung stärker profitieren, da die zusätzlichen Tage länger undwärmer sind als dies für die frühen Phasen der Fall ist. Um die relative Änderung in PAS im Vergleich der Spezies abzuschätzen, müssen allerdings auch die Veränderungen in den Herbstphasen berücksichtigt werden. Der deutliche Unterschied zwischen frühen und späten Frühjahrsphasen konnte durch die Anwendung einer neuen Methode zur Konstruktion von Zeitreihen herausgearbeitet werden. Der neue methodische Ansatz erlaubte die Ableitung verlässlicher 100-jähriger Zeitreihen und die Konstruktion von lokalen kombinierten Zeitreihen, welche die Datenverfügbarkeit für die Modellentwicklung erhöhten. Ausser analysierten Protokollierungsfehlern wurden mikroklimatische, genetische und Beobachtereinflüsse als Quellen von Unsicherheit in phänologischen Daten identifiziert. Phänologischen Beobachtungen eines Ortes können schätzungsweise 24 Tage um das parametrische Mittel schwanken.Dies unterstützt die 30-Tage Regel für die Detektion von Ausreissern. Neue Phänologiemodelle, die den Blattaustrieb aus täglichen Temperaturreihen simulieren, wurden entwickelt. Diese Modelle basieren auf einfachen Interaktionen zwischen aktivierenden und hemmenden Substanzen, welche die Entwicklungsstadien einer Pflanze bestimmen. Im Allgemeinen konnten die neuen Modelle die Beobachtungsdaten besser simulieren als die klassischen Modelle. Weitere Hauptresultate waren: - Der Bias der klassischen Modelle, d.h. Überschätzung von frühen und Unterschätzung von späten Beobachtungen, konnte reduziert, aber nicht vollständig eliminiert werden. - Die besten Modellvarianten für verschiedene Spezies wiesen darauf hin, dass für die späten Frühjahrsphasen die Tageslänge eine wichtigere Rolle spielt als für die frühen Phasen. - Die Vernalisation spielte gegenüber den Temperaturen kurz vor dem Blattaustrieb nur eine untergeordnete Rolle. N2 - The length of the vegetation period (VP) plays a central role for the interannual variation of carbon fixation of terrestrial ecosystems. Observational data analysis has indicated that the length of the VP has increased in the last decades in the northern latitudes mainly due to an advancement of bud burst (BB). This phenomenon has been widely discussed in the context of Global Warming because phenology is correlated to temperatures. Analyzing the patterns of spring phenology over the last century in Southern Germany provided two main findings: - The strong advancement of spring phases especially in the decade before 1999 is not a singular event in the course of the 20th century. Similar trends were also observed in earlier decades. Distinct periods of varying trend behavior for important spring phases could be distinguished. - Marked differences in trend behavior between the early and late spring phases were detected. Early spring phases changed as regards the magnitude of their negative trends from strong negative trends between 1931 and 1948 to moderate negative trends between 1948 and 1984 and back to strong negative trends between 1984 and 1999. Late spring phases showed a different behavior. Negative trends between 1931 and 1948 are followed by marked positive trends between 1948 and 1984 and then strong negative trends between 1984 and 1999. This marked difference in trend development between early and late spring phases was also found all over Germany for the two periods 1951 to 1984 and 1984 to 1999. The dominating influence of temperature on spring phenology and its modifying effect on autumn phenology was confirmed in this thesis. However, - temperature functions determining spring phenology were not significantly correlated with a global annual CO2 signal which was taken as a proxy for a Global Warming pattern. - an index for large scale regional circulation patterns (NAO index) could only to a small part explain the observed phenological variability in spring. The observed different trend behavior of early and late spring phases is explained by the differing behavior of mean March and April temperatures. Mean March temperatures have increased on average over the 20th century accompanied by an increasing variation in the last 50 years. April temperatures, however, decreased between the end of the 1940s and the mid-1980s, followed by a marked warming after the mid-1980s. It can be concluded that the advancement of spring phenology in recent decades are part of multi-decadal fluctuations over the 20th century that vary with the species and the relevant seasonal temperatures. Because of these fluctuations a correlation with an observed Global Warming signal could not be found. On average all investigated spring phases advanced between 5 and 20 days between 1951 and 1999 for all Natural Regions in Germany. A marked difference be! tween late and early spring phases is due to the above mentioned differing behavior before and after the mid-1980s. Leaf coloring (LC) was delayed between 1951 and 1984 for all tree species. However, after 1984 LC was advanced. Length of the VP increased between 1951 and 1999 for all considered tree species by an average of ten days throughout Germany. It is predominately the change in spring phases which contributes to a change in the potentially absorbed radiation. Additionally, it is the late spring species that are relatively more favored by an advanced BB because they can additionally exploit longer days and higher temperatures per day advancement. To assess the relative change in potentially absorbed radiation among species, changes in both spring and autumn phenology have to be considered as well as where these changes are located in the year. For the detection of the marked difference between early and late spring phenology a new time series construction method was developed. This method allowed the derivation of reliable time series that spanned over 100 years and the construction of locally combined time series increasing the available data for model development. Apart from analyzed protocolling errors, microclimatic site influences, genetic variation and the observers were identified as sources of uncertainty of phenological observational data. It was concluded that 99% of all phenological observations at a certain site will vary within approximately 24 days around the parametric mean. This supports to the proposed 30-day rule to detect outliers. New phenology models that predict local BB from daily temperature time series were developed. These models were based on simple interactions between inhibitory and promotory agents that are assumed to control the developmental status of a plant. Apart from the fact that, in general, the new models fitted and predicted the observations better than classical models, the main modeling results were: - The bias of the classical models, i.e. overestimation of early observations and underestimation of late observations, could be reduced but not completely removed. - The different favored model structures for each species indicated that for the late spring phases photoperiod played a more dominant role than for early spring phases. - Chilling only plays a subordinate role for spring BB compared to temperatures directly preceding BB. KW - Phänologie KW - kombinierte Zeitreihen KW - Physiologie-basierte Modelle KW - Unsicherheit KW - Variabilität KW - Ausreisser KW - Trends KW - Naturräume KW - Trendwendepunkte KW - Fag KW - phenology KW - combined time series KW - physiology-based models KW - uncertainty KW - variability KW - outliers KW - trends KW - Natural Regions KW - trend turning points KW - Fagus syl Y1 - 2002 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-0000532 ER - TY - JOUR A1 - Rottler, Erwin A1 - Francke, Till A1 - Bürger, Gerd A1 - Bronstert, Axel T1 - Long-term changes in central European river discharge for 1869–2016 BT - impact of changing snow covers, reservoir constructions and an intensified hydrological cycle JF - Hydrology and Earth System Sciences N2 - Recent climatic changes have the potential to severely alter river runoff, particularly in snow-dominated river basins. Effects of changing snow covers superimpose with changes in precipitation and anthropogenic modifications of the watershed and river network. In the attempt to identify and disentangle long-term effects of different mechanisms, we employ a set of analytical tools to extract long-term changes in river runoff at high resolution. We combine quantile sampling with moving average trend statistics and empirical mode decomposition and apply these tools to discharge data recorded along rivers with nival, pluvial and mixed flow regimes as well as temperature and precipitation data covering the time frame 1869-2016. With a focus on central Europe, we analyse the long-term impact of snow cover and precipitation changes along with their interaction with reservoir constructions. Our results show that runoff seasonality of snow-dominated rivers decreases. Runoff increases in winter and spring, while discharge decreases in summer and at the beginning of autumn. We attribute this redistribution of annual flow mainly to reservoir constructions in the Alpine ridge. During the course of the last century, large fractions of the Alpine rivers were dammed to produce hydropower. In recent decades, runoff changes induced by reservoir constructions seem to overlap with changes in snow cover. We suggest that Alpine signals propagate downstream and affect runoff far outside the Alpine area in river segments with mixed flow regimes. Furthermore, our results hint at more (intense) rain-fall in recent decades. Detected increases in high discharge can be traced back to corresponding changes in precipitation. KW - empirical mode decomposition KW - atmospheric blocking KW - heavy precipitation KW - streamflow trends KW - climate-change KW - rhine basin KW - time-series KW - events KW - Switzerland KW - variability Y1 - 2020 U6 - https://doi.org/10.5194/hess-24-1721-2020 SN - 1027-5606 SN - 1607-7938 VL - 24 IS - 4 SP - 1721 EP - 1740 PB - Copernicus CY - Göttingen ER - TY - GEN A1 - Rottler, Erwin A1 - Francke, Till A1 - Bürger, Gerd A1 - Bronstert, Axel T1 - Long-term changes in central European river discharge for 1869–2016 BT - Impact of changing snow covers, reservoir constructions and an intensified hydrological cycle T2 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Recent climatic changes have the potential to severely alter river runoff, particularly in snow-dominated river basins. Effects of changing snow covers superimpose with changes in precipitation and anthropogenic modifications of the watershed and river network. In the attempt to identify and disentangle long-term effects of different mechanisms, we employ a set of analytical tools to extract long-term changes in river runoff at high resolution. We combine quantile sampling with moving average trend statistics and empirical mode decomposition and apply these tools to discharge data recorded along rivers with nival, pluvial and mixed flow regimes as well as temperature and precipitation data covering the time frame 1869-2016. With a focus on central Europe, we analyse the long-term impact of snow cover and precipitation changes along with their interaction with reservoir constructions. Our results show that runoff seasonality of snow-dominated rivers decreases. Runoff increases in winter and spring, while discharge decreases in summer and at the beginning of autumn. We attribute this redistribution of annual flow mainly to reservoir constructions in the Alpine ridge. During the course of the last century, large fractions of the Alpine rivers were dammed to produce hydropower. In recent decades, runoff changes induced by reservoir constructions seem to overlap with changes in snow cover. We suggest that Alpine signals propagate downstream and affect runoff far outside the Alpine area in river segments with mixed flow regimes. Furthermore, our results hint at more (intense) rain-fall in recent decades. Detected increases in high discharge can be traced back to corresponding changes in precipitation. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 1412 KW - empirical mode decomposition KW - atmospheric blocking KW - heavy precipitation KW - streamflow trends KW - climate-change KW - rhine basin KW - time-series KW - events KW - Switzerland KW - variability Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-517763 SN - 1866-8372 IS - 4 ER - TY - THES A1 - Pregla, Dorothea T1 - Variability in sentence processing performance in German people with aphasia and unimpaired German native speakers T1 - Variabilität in der Satzverarbeitungsleistung von deutschsprachigen Personen mit und ohne Aphasie N2 - Individuals with aphasia vary in the speed and accuracy they perform sentence comprehension tasks. Previous results indicate that the performance patterns of individuals with aphasia vary between tasks (e.g., Caplan, DeDe, & Michaud, 2006; Caplan, Michaud, & Hufford, 2013a). Similarly, it has been found that the comprehension performance of individuals with aphasia varies between homogeneous test sentences within and between sessions (e.g., McNeil, Hageman, & Matthews, 2005). These studies ascribed the variability in the performance of individuals with aphasia to random noise. This conclusion would be in line with an influential theory on sentence comprehension in aphasia, the resource reduction hypothesis (Caplan, 2012). However, previous studies did not directly compare variability in language-impaired and language-unimpaired adults. Thus, it is still unclear how the variability in sentence comprehension differs between individuals with and without aphasia. Furthermore, the previous studies were exclusively carried out in English. Therefore, the findings on variability in sentence processing in English still need to be replicated in a different language. This dissertation aims to give a systematic overview of the patterns of variability in sentence comprehension performance in aphasia in German and, based on this overview, to put the resource reduction hypothesis to the test. In order to reach the first aim, variability was considered on three different dimensions (persons, measures, and occasions) following the classification by Hultsch, Strauss, Hunter, and MacDonald (2011). At the dimension of persons, the thesis compared the performance of individuals with aphasia and language-unimpaired adults. At the dimension of measures, this work explored the performance across different sentence comprehension tasks (object manipulation, sentence-picture matching). Finally, at the dimension of occasions, this work compared the performance in each task between two test sessions. Several methods were combined to study variability to gain a large and diverse database. In addition to the offline comprehension tasks, the self-paced-listening paradigm and the visual world eye-tracking paradigm were used in this work. The findings are in line with the previous results. As in the previous studies, variability in sentence comprehension in individuals with aphasia emerged between test sessions and between tasks. Additionally, it was possible to characterize the variability further using hierarchical Bayesian models. For individuals with aphasia, it was shown that both between-task and between-session variability are unsystematic. In contrast to that, language-unimpaired individuals exhibited systematic differences between measures and between sessions. However, these systematic differences occurred only in the offline tasks. Hence, variability in sentence comprehension differed between language-impaired and language-unimpaired adults, and this difference could be narrowed down to the offline measures. Based on this overview of the patterns of variability, the resource reduction hypothesis was evaluated. According to the hypothesis, the variability in the performance of individuals with aphasia can be ascribed to random fluctuations in the resources available for sentence processing. Given that the performance of the individuals with aphasia varied unsystematically, the results support the resource reduction hypothesis. Furthermore, the thesis proposes that the differences in variability between language-impaired and language-unimpaired adults can also be explained by the resource reduction hypothesis. More specifically, it is suggested that the systematic changes in the performance of language-unimpaired adults are due to decreasing fluctuations in available processing resources. In parallel, the unsystematic variability in the performance of individuals with aphasia could be due to constant fluctuations in available processing resources. In conclusion, the systematic investigation of variability contributes to a better understanding of language processing in aphasia and thus enriches aphasia research. N2 - Personen mit Aphasie unterscheiden sich in der Geschwindigkeit und Genauigkeit, mit der sie Satzverständnisaufgaben lösen. Ergebnisse früherer Studien weisen darauf hin, dass die Leistungsmuster von Personen mit Aphasie zwischen verschiedenen Aufgaben variieren (z.B. Caplan, DeDe & Michaud, 2006; Caplan, Michaud & Hufford, 2013a). In ähnlicher Weise wurde festgestellt, dass die Verständnisleistung von Personen mit Aphasie zwischen ähnlich komplexen Testsätzen innerhalb und zwischen Sitzungen variiert (z.B. McNeil, Hageman & Matthews, 2005). In diesen Studien wurde die Variabilität in der Leistung von Personen mit Aphasie auf bloßen Zufall durch Rauschen in den Daten zurückgeführt. Diese Schlussfolgerung steht im Einklang mit einer einflussreichen Theorie zum Satzverständnis bei Aphasie, der resource reduction hypothesis (Caplan, 2012). In früheren Studien wurde die Variabilität bei Personen mit und ohne Aphasie jedoch nicht direkt verglichen. Daher ist noch unklar, wie sich die Variabilität im Satzverständnis zwischen Personen mit und ohne Aphasie unterscheidet. Außerdem wurden die bisherigen Studien ausschließlich im Englischen durchgeführt. Eine Replikation der Ergebnisse in einer anderen Sprache steht bisher noch aus. Ziel dieser Arbeit ist es, einen systematischen Überblick über die Variabilitätsmuster in der Satzverständnisleistung bei Aphasie im Deutschen zu geben und darauf aufbauend die resource reduction hypothesis zu überprüfen. Für das erste Ziel wurde die Variabilität in Anlehnung an die Klassifikation von Hultsch, Strauss, Hunter und MacDonald (2011) auf drei verschiedenen Ebenen (Personen, Maße und Messzeitpunkte) untersucht. Auf der Ebene der Personen wurden die Leistungen von Personen mit und ohne Aphasie miteinander verglichen. Auf der Ebene der Maße wurde die Leistung beider Versuchspersonengruppen über verschiedene Satzverständninsaufgaben hinweg untersucht (Objektmanipulierung, Satz-Bild-Zuordnung). Auf der Ebene der Messzeitpunkte wurden die Leistungen in jeder Aufgabe zwischen zwei Testsitzungen verglichen. Um eine große und vielfältige Datenbasis zu erhalten, wurden mehrere Methoden zur Untersuchung der Variabilität kombiniert. So wurden zusätzlich zu den Offline-Verständnisaufgaben in dieser Arbeit self-paced-listening (selbstgesteuertes Hören) und visual world eye-tracking (Blickbewegungsmessung beim Betrachten von Bildern) verwendet. Die Ergebnisse stimmen mit den bisherigen Befunden überein. Wie in den vorangegangenen Studien trat Variabilität im Satzverständnis bei Personen mit Aphasie zwischen den Testsitzungen und zwischen den Aufgaben auf. Darüber hinaus wurde die Variabilität mittels hierarchischer Bayesianischer Modelle weiter charakterisiert. Für Personen mit Aphasie war sowohl die Variabilität zwischen den Aufgaben als auch zwischen den Sitzungen unsystematisch. Im Gegensatz dazu zeigten sich bei Personen ohne Aphasie systematische Unterschiede zwischen den Aufgaben und zwischen den Sitzungen. Diese systematischen Unterschiede traten jedoch nur bei den Offline-Verständnisaufgaben auf. Die Variabilität im Satzverständnis unterscheidet sich also zwischen Personen mit und ohne Aphasie in der Offline-Verständnisleistung. Auf der Grundlage dieses Überblicks über die Variabilitätsmuster wurde die resource reduction hypothesis evaluiert. Laut dieser Hypothese kann die Variabilität in der Leistung von Personen mit Aphasie auf zufällige Schwankungen in den verfügbaren Satzverarbeitungsressourcen zurückgeführt werden. Da die Leistung der Personen mit Aphasie unsystematisch variiert, stimmen die Ergebnisse mit der resource reduction hypothesis überein. Zusätzlich lassen sich auch die Unterschiede in der Variabilität zwischen Personen mit und ohne Aphasie durch die resource reduction hypothesis erklären. Die systematischen Veränderungen im Satzverständnis bei Personen ohne Aphasie werden auf eine Abnahme der Fluktuationen in den Verarbeitungsressourcen zurückgeführt. Parallel dazu könnte die unsystematische Variabilität in der Leistung von Personen mit Aphasie auf konstante Schwankungen der verfügbaren Verarbeitungsressourcen zurückgeführt werden. Zusammenfassend lässt sich sagen, dass die systematische Untersuchung der Variabilität zu einem besseren Verständnis der Sprachverarbeitung bei Aphasie beiträgt und somit die Aphasieforschung bereichert. KW - aphasia KW - sentence comprehension KW - variability KW - resource reduction KW - Aphasie KW - Satzverständnis KW - Variabilität KW - Reduzierte Ressourcen Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-614201 ER - TY - GEN A1 - Nord, Guillaume A1 - Boudevillain, Brice A1 - Berne, Alexis A1 - Branger, Flora A1 - Braud, Isabelle A1 - Dramais, Guillaume A1 - Gérard, Simon A1 - Le Coz, Jérôme A1 - Legoût, Cédric A1 - Molinié, Gilles A1 - Van Baelen, Joel A1 - Vandervaere, Jean-Pierre A1 - Andrieu, Julien A1 - Aubert, Coralie A1 - Calianno, Martin A1 - Delrieu, Guy A1 - Grazioli, Jacopo A1 - Hachani, Sahar A1 - Horner, Ivan A1 - Huza, Jessica A1 - Le Boursicaud, Raphaël A1 - Raupach, Timothy H. A1 - Teuling, Adriaan J. A1 - Uber, Magdalena A1 - Vincendon, Béatrice A1 - Wijbrans, Annette T1 - A high space–time resolution dataset linking meteorological forcing and hydro-sedimentary response in a mesoscale Mediterranean catchment (Auzon) of the Ardèche region, France T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - A comprehensive hydrometeorological dataset is presented spanning the period 1 January 201131 December 2014 to improve the understanding of the hydrological processes leading to flash floods and the relation between rainfall, runoff, erosion and sediment transport in a mesoscale catchment (Auzon, 116 km(2)) of the Mediterranean region. Badlands are present in the Auzon catchment and well connected to high-gradient channels of bedrock rivers which promotes the transfer of suspended solids downstream. The number of observed variables, the various sensors involved (both in situ and remote) and the space-time resolution (similar to km(2), similar to min) of this comprehensive dataset make it a unique contribution to research communities focused on hydrometeorology, surface hydrology and erosion. Given that rainfall is highly variable in space and time in this region, the observation system enables assessment of the hydrological response to rainfall fields. Indeed, (i) rainfall data are provided by rain gauges (both a research network of 21 rain gauges with a 5 min time step and an operational network of 10 rain gauges with a 5 min or 1 h time step), S-band Doppler dual-polarization radars (1 km(2), 5 min resolution), disdrometers (16 sensors working at 30 s or 1 min time step) and Micro Rain Radars (5 sensors, 100m height resolution). Additionally, during the special observation period (SOP-1) of the HyMeX (Hydrological Cycle in the Mediterranean Experiment) project, two X-band radars provided precipitation measurements at very fine spatial and temporal scales (1 ha, 5 min). (ii) Other meteorological data are taken from the operational surface weather observation stations of Meteo-France (including 2m air temperature, atmospheric pressure, 2 m relative humidity, 10m wind speed and direction, global radiation) at the hourly time resolution (six stations in the region of interest). (iii) The monitoring of surface hydrology and suspended sediment is multi-scale and based on nested catchments. Three hydrometric stations estimate water discharge at a 2-10 min time resolution. Two of these stations also measure additional physico-chemical variables (turbidity, temperature, conductivity) and water samples are collected automatically during floods, allowing further geochemical characterization of water and suspended solids. Two experimental plots monitor overland flow and erosion at 1 min time resolution on a hillslope with vineyard. A network of 11 sensors installed in the intermittent hydrographic network continuously measures water level and water temperature in headwater subcatchments (from 0.17 to 116 km(2)) at a time resolution of 2-5 min. A network of soil moisture sensors enables the continuous measurement of soil volumetric water content at 20 min time resolution at 9 sites. Additionally, concomitant observations (soil moisture measurements and stream gauging) were performed during floods between 2012 and 2014. Finally, this dataset is considered appropriate for understanding the rainfall variability in time and space at fine scales, improving areal rainfall estimations and progressing in distributed hydrological and erosion modelling. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 671 KW - hydraulic properties KW - soil moisture KW - flash floods KW - rainfall KW - radar KW - scale KW - variability KW - transport KW - erosion KW - model Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419127 SN - 1866-8372 IS - 671 ER - TY - JOUR A1 - Mumm, Rebekka A1 - Czernitzki, Anna-Franziska A1 - Bents, Dominik A1 - Musalek, Martin T1 - Socioeconomic situation and growth in infants and juveniles JF - Anthropologischer Anzeiger : journal of biological and clinical anthropology ; Mitteilungsorgan der Gesellschaft für Anthropologie N2 - Background: Physical growth of children and adolescents depends on the interaction of genetic and environmental factors e.g. diet and living conditions. Aim: We aim to discuss the influence of socioeconomic situation, using income inequality and GDP per capita as indicators, on body height, body weight and the variability of height and weight in infants and juveniles. Material and methods: We re-analyzed data from 439 growth studies on height and weight published during the last 35 years. We added year-and country-matched GDP per capita (in current US$) and the Gini coefficient for each study. The data were divided into two age groups: infants (age 2) and juveniles (age 7). We used Pearson correlation and principal component analysis to investigate the data. Results: Gini coefficient negatively correlated with body height and body weight in infants and juveniles. GDP per capita showed a positive correlation with height and weight in both age groups. In infants the standard deviation of height increases with increasing Gini coefficient. The opposite is true for juveniles. A correlation of weight variability and socioeconomic indicators is absent in infants. In juveniles the variability of weight increases with declining Gini coefficient and increasing logGDP per capita. Discussion: Poverty and income inequality are generally associated with poor growth in height and weight. The analysis of the within-population height and weight variations however, shows that the associations between wealth, income, and anthropometric parameters are very complex and cannot be explained by common wisdom. They point towards an independent regulation of height and weight. KW - socioeconomic situation KW - height KW - weight KW - variability KW - community effect Y1 - 2017 U6 - https://doi.org/10.1127/anthranz/2017/0706 SN - 0003-5548 VL - 74 SP - 101 EP - 107 PB - Schweizerbart CY - Stuttgart ER - TY - GEN A1 - Molnos, Sonja A1 - Mamdouh, Tarek A1 - Petri, Stefan A1 - Nocke, Thomas A1 - Weinkauf, Tino A1 - Coumou, Dim T1 - A network-based detection scheme for the jet stream core T2 - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe N2 - The polar and subtropical jet streams are strong upper-level winds with a crucial influence on weather throughout the Northern Hemisphere midlatitudes. In particular, the polar jet is located between cold arctic air to the north and warmer subtropical air to the south. Strongly meandering states therefore often lead to extreme surface weather. Some algorithms exist which can detect the 2-D (latitude and longitude) jets' core around the hemisphere, but all of them use a minimal threshold to determine the subtropical and polar jet stream. This is particularly problematic for the polar jet stream, whose wind velocities can change rapidly from very weak to very high values and vice versa. We develop a network-based scheme using Dijkstra's shortest-path algorithm to detect the polar and subtropical jet stream core. This algorithm not only considers the commonly used wind strength for core detection but also takes wind direction and climatological latitudinal position into account. Furthermore, it distinguishes between polar and subtropical jet, and between separate and merged jet states. The parameter values of the detection scheme are optimized using simulated annealing and a skill function that accounts for the zonal-mean jet stream position (Rikus, 2015). After the successful optimization process, we apply our scheme to reanalysis data covering 1979-2015 and calculate seasonal-mean probabilistic maps and trends in wind strength and position of jet streams. We present longitudinally defined probability distributions of the positions for both jets for all on the Northern Hemisphere seasons. This shows that winter is characterized by two well-separated jets over Europe and Asia (ca. 20 degrees W to 140 degrees E). In contrast, summer normally has a single merged jet over the western hemisphere but can have both merged and separated jet states in the eastern hemisphere. With this algorithm it is possible to investigate the position of the jets' cores around the hemisphere and it is therefore very suitable to analyze jet stream patterns in observations and models, enabling more advanced model-validation. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 625 KW - Southern-Hemisphere KW - variability KW - weather KW - driven KW - amplification KW - circulation KW - reanalysis KW - extremes KW - climate KW - summer Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-419099 SN - 1866-8372 IS - 625 SP - 75 EP - 89 ER - TY - JOUR A1 - Menon, Arathy A1 - Levermann, Anders A1 - Schewe, Jacob T1 - Enhanced future variability during India's rainy season JF - Geophysical research letters N2 - The Indian summer monsoon shapes the livelihood of a large share of the world's population. About 80% of annual precipitation over India occurs during the monsoon season from June through September. Next to its seasonal mean rainfall, the day-to-day variability is crucial for the risk of flooding, national water supply, and agricultural productivity. Here we show that the latest ensemble of climate model simulations, prepared for the AR-5 of the Intergovernmental Panel on Climate Change, consistently projects significant increases in day-to-day rainfall variability under unmitigated climate change. The relative increase by the period 2071-2100 with respect to the control period 1871-1900 ranges from 13% to 50% under the strongest scenario (Representative Concentration Pathways, RCP-8.5), in the 10 models with the most realistic monsoon climatology; and 13% to 85% when all the 20 models are considered. The spread across models reduces when variability increase per degree of global warming is considered, which is independent of the scenario in most models, and is 8% +/- 4%/K on average. This consistent projection across 20 comprehensive climate models provides confidence in the results and suggests the necessity of profound adaptation measures in the case of unmitigated climate change. KW - monsoon KW - variability KW - CMIP-5 Y1 - 2013 U6 - https://doi.org/10.1002/grl.50583 SN - 0094-8276 VL - 40 IS - 12 SP - 3242 EP - 3247 PB - American Geophysical Union CY - Washington ER -