@article{JeltschGrimmReegetal.2019, author = {Jeltsch, Florian and Grimm, Volker and Reeg, Jette and Schl{\"a}gel, Ulrike E.}, title = {Give chance a chance}, series = {Ecosphere}, volume = {10}, journal = {Ecosphere}, number = {5}, publisher = {ESA}, address = {Ithaca, NY}, issn = {2150-8925}, doi = {10.1002/ecs2.2700}, pages = {19}, year = {2019}, abstract = {A large part of biodiversity theory is driven by the basic question of what allows species to coexist in spite of a confined number of niches. A substantial theoretical background to this question is provided by modern coexistence theory (MCT), which rests on mathematical approaches of invasion analysis to categorize underlying mechanisms into factors that reduce either niche overlap (stabilizing mechanisms) or the average fitness differences of species (equalizing mechanisms). While MCT has inspired biodiversity theory in the search for these underlying mechanisms, we feel that the strong focus on coexistence causes a bias toward the most abundant species and neglects the plethora of species that are less abundant and often show high local turnover. Given the more stochastic nature of their occurrence, we advocate a complementary cross-level approach that links individuals, small populations, and communities and explicitly takes into account (1) a more complete inclusion of environmental and demographic stochasticity affecting small populations, (2) intraspecific trait variation and behavioral plasticity, and (3) local heterogeneities, interactions, and feedbacks. Focusing on mechanisms that drive the temporary coviability of species rather than infinite coexistence, we suggest a new approach that could be dubbed coviability analysis (CVA). From a modeling perspective, CVA builds on the merged approaches of individual-based modeling and population viability analysis but extends them to the community level. From an empirical viewpoint, CVA calls for a stronger integration of spatiotemporal data on variability and noise, changing drivers, and interactions at the level of individuals. The resulting large volumes of data from multiple sources could be strongly supported by novel techniques tailored to the discovery of complex patterns in high-dimensional data. By complementing MCT through a stronger focus on the coviability of less common species, this approach can help make modern biodiversity theory more comprehensive, predictive, and relevant for applications.}, language = {en} } @article{Hermanns2023, author = {Hermanns, Jolanda}, title = {Chemieunterricht f{\"u}r heterogene Lerngruppen - eine Lehrveranstaltung f{\"u}r Lehramtsstudierende}, series = {PSI-Potsdam: Ergebnisbericht zu den Aktivit{\"a}ten im Rahmen der Qualit{\"a}tsoffensive Lehrerbildung (2019-2023) (Potsdamer Beitr{\"a}ge zur Lehrerbildung und Bildungsforschung ; 3)}, journal = {PSI-Potsdam: Ergebnisbericht zu den Aktivit{\"a}ten im Rahmen der Qualit{\"a}tsoffensive Lehrerbildung (2019-2023) (Potsdamer Beitr{\"a}ge zur Lehrerbildung und Bildungsforschung ; 3)}, number = {3}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, isbn = {978-3-86956-568-2}, issn = {2626-3556}, doi = {10.25932/publishup-61783}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-617836}, pages = {205 -- 213}, year = {2023}, abstract = {Im Sommersemester 2022 wurde erstmalig die Lehrveranstaltung „Chemieunterricht f{\"u}r heterogene Lerngruppen" angeboten. Diese Lehrveranstaltung ist im Rahmen von PSI-Potsdam im Schwerpunkt „Inklusion und Heterogenit{\"a}t" entstanden. Die Lehrveranstaltung wurde synchron online durchgef{\"u}hrt. Die Studierenden erhielten viele M{\"o}glichkeiten zur Diskussion sowie zur selbstst{\"a}ndigen Erstellung von Unterrichtsmaterialien. Zum erfolgreichen Abschluss des Moduls erstellten die Studierenden ein Portfolio zu einem selbst gew{\"a}hlten Thema. Die Lehrveranstaltung wurde von den Studierenden sehr gut bewertet.}, language = {de} } @article{HennigStockmannKuehn2020, author = {Hennig, Theresa and Stockmann, Madlen and K{\"u}hn, Michael}, title = {Simulation of diffusive uranium transport and sorption processes in the Opalinus Clay}, series = {Applied geochemistry : journal of the International Association of Geochemistry and Cosmochemistry}, volume = {123}, journal = {Applied geochemistry : journal of the International Association of Geochemistry and Cosmochemistry}, publisher = {Elsevier}, address = {Oxford}, issn = {0883-2927}, doi = {10.1016/j.apgeochem.2020.104777}, pages = {9}, year = {2020}, abstract = {Diffusive transport and sorption processes of uranium in the Swiss Opalinus Clay were investigated as a function of partial pressure of carbon dioxide pCO(2), varying mineralogy in the facies and associated changes in porewater composition. Simulations were conducted in one-dimensional diffusion models on the 100 m-scale for a time of one million years using a bottom-up approach based on mechanistic surface complexation models as well as cation exchange to quantify sorption. Speciation calculations have shown, uranium is mainly present as U(VI) and must therefore be considered as mobile for in-situ conditions. Uranium migrated up to 26 m in both, the sandy and the carbonate-rich facies, whereas in the shaly facies 16 m was the maximum. The main species was the anionic complex CaUO2(CO3)(3)(2-) . Hence, anion exclusion was taken into account and further reduced the migration distances by 30 \%. The concentrations of calcium and carbonates reflected by the set pCO(2) determine speciation and activity of uranium and consequently the sorption behaviour. Our simulation results allow for the first time to prioritize on the far-field scale the governing parameters for diffusion and sorption of uranium and hence outline the sensitivity of the system. Sorption processes are controlled in descending priority by the carbonate and calcium concentrations, pH, pe and the clay mineral content. Therefore, the variation in porewater composition resulting from the heterogeneity of the facies in the Opalinus Clay formation needs to be considered in the assessment of uranium migration in the far field of a potential repository.}, language = {en} } @article{HennigKuehn2021, author = {Hennig, Theresa and K{\"u}hn, Michael}, title = {Surrogate model for multi-component diffusion of Uranium through Opalinus Clay on the host rock scale}, series = {Applied Sciences : open access journal}, volume = {11}, journal = {Applied Sciences : open access journal}, number = {2}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app11020786}, pages = {21}, year = {2021}, abstract = {Multi-component (MC) diffusion simulations enable a process based and more precise approach to calculate transport and sorption compared to the commonly used single-component (SC) models following Fick's law. The MC approach takes into account the interaction of chemical species in the porewater with the diffuse double layer (DDL) adhering clay mineral surfaces. We studied the shaly, sandy and carbonate-rich facies of the Opalinus Clay. High clay contents dominate diffusion and sorption of uranium. The MC simulations show shorter diffusion lengths than the SC models due to anion exclusion from the DDL. This hampers diffusion of the predominant species CaUO2(CO3)32-. On the one side, species concentrations and ionic strengths of the porewater and on the other side surface charge of the clay minerals control the composition and behaviour of the DDL. For some instances, it amplifies the diffusion of uranium. We developed a workflow to transfer computationally intensive MC simulations to SC models via calibrated effective diffusion and distribution coefficients. Simulations for one million years depict maximum uranium diffusion lengths between 10 m and 35 m. With respect to the minimum requirement of a thickness of 100 m, the Opalinus Clay seems to be a suitable host rock for nuclear waste repositories.}, language = {en} } @phdthesis{Graeff2011, author = {Gr{\"a}ff, Thomas}, title = {Soil moisture dynamics and soil moisture controlled runoff processes at different spatial scales : from observation to modelling}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-54470}, school = {Universit{\"a}t Potsdam}, year = {2011}, abstract = {Soil moisture is a key state variable that controls runoff formation, infiltration and partitioning of radiation into latent and sensible heat. However, the experimental characterisation of near surface soil moisture patterns and their controls on runoff formation remains a challenge. This subject was one aspect of the BMBF-funded OPAQUE project (operational discharge and flooding predictions in head catchments). As part of that project the focus of this dissertation is on: (1) testing the methodology and feasibility of the Spatial TDR technology in producing soil moisture profiles along TDR probes, including an inversion technique of the recorded signal in heterogeneous field soils, (2) the analysis of spatial variability and temporal dynamics of soil moisture at the field scale including field experiments and hydrological modelling, (3) the application of models of different complexity for understanding soil moisture dynamics and its importance for runoff generation as well as for improving the prediction of runoff volumes. To fulfil objective 1, several laboratory experiments were conducted to understand the influence of probe rod geometry and heterogeneities in the sampling volume under different wetness conditions. This includes a detailed analysis on how these error sources affect retrieval of soil moisture profiles in soils. Concerning objective 2 a sampling strategy of two TDR clusters installed in the head water of the Wilde Weißeritz catchment (Eastern Ore Mountains, Germany) was used to investigate how well "the catchment state" can be characterised by means of distributed soil moisture data observed at the field scale. A grassland site and a forested site both located on gentle slopes were instrumented with two Spatial TDR clusters that consist of up to 39 TDR probes. Process understanding was gained by modelling the interaction of evapotranspiration and soil moisture with the hydrological process model CATFLOW. A field scale irrigation experiment was carried out to investigate near subsurface processes at the hillslope scale. The interactions of soil moisture and runoff formation were analysed using discharge data from three nested catchments: the Becherbach with a size of 2 km², the Rehefeld catchment (17 km²) and the superordinate Ammelsdorf catchment (49 km²). Statistical analyses including observations of pre-event runoff, soil moisture and different rainfall characteristics were employed to predict stream flow volume. On the different scales a strong correlation between the average soil moisture and the runoff coefficients of rainfall-runoff events could be found, which almost explains equivalent variability as the pre-event runoff. Furthermore, there was a strong correlation between surface soil moisture and subsurface wetness with a hysteretic behaviour between runoff soil moisture. To fulfil objective 3 these findings were used in a generalised linear model (GLM) analysis which combines state variables describing the catchments antecedent wetness and variables describing the meteorological forcing in order to predict event runoff coefficients. GLM results were compared to simulations with the catchment model WaSiM ETH. Hereby were the model results of the GLMs always better than the simulations with WaSiM ETH. The GLM analysis indicated that the proposed sampling strategy of clustering TDR probes in typical functional units is a promising technique to explore soil moisture controls on runoff generation and can be an important link between the scales. Long term monitoring of such sites could yield valuable information for flood warning and forecasting by identifying critical soil moisture conditions for the former and providing a better representation of the initial moisture conditions for the latter.}, language = {en} } @article{DietrichLazarides2019, author = {Dietrich, Julia and Lazarides, Rebecca}, title = {Gendered development of motivational belief patterns in mathematics across a school year and career plans in math-related fields}, series = {Frontiers in psychology}, volume = {10}, journal = {Frontiers in psychology}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-1078}, doi = {10.3389/fpsyg.2019.01472}, pages = {5}, year = {2019}, abstract = {Rooted in Eccles and colleagues' expectancy-value theory, this study aimed to examine how expectancies and different facets of task value combine to diverse profiles of motivational beliefs, how such complex profiles develop across a school year, and how they relate to gender and career plans. Despite abundant research on the association between gender and motivational beliefs, there is a paucity of knowledge regarding the gendered development of student motivational belief profiles in specific domains. Using latent-transition analysis in a sample of N = 751 ninth to tenth graders (55.9\% girls), we investigated girls' and boys' development of motivational belief profiles (profile paths) in mathematics across a school year. We further analyzed the association between these profile paths and math-related career plans. The results revealed four motivational belief profiles: high motivation (intrinsic and attainment oriented), balanced above average motivation, average motivation (attainment and cost oriented), and low motivation (cost oriented). Girls were less likely than expected by chance to remain in the high motivation profile, while the opposite was true for boys. The math-relatedness of students' career plans was significantly higher in the "stable high motivation" profile path than in all other stable profile paths.}, language = {en} } @article{BiegertBradyHipp2022, author = {Biegert, Thomas and Brady, David and Hipp, Lena}, title = {Cross-national variation in the relationship between welfare generosity and single mother employment}, series = {The annals of the American Academy of Political and Social Science}, volume = {702}, journal = {The annals of the American Academy of Political and Social Science}, number = {1}, publisher = {SAGE Publishing}, address = {Thousand Oaks}, issn = {0002-7162}, doi = {10.1177/00027162221120760}, pages = {37 -- 54}, year = {2022}, abstract = {Reform of the U.S. welfare system in 1996 spurred claims that cuts to welfare programs effectively incentivized single mothers to find employment. It is difficult to assess the veracity of those claims, however, absent evidence of how the relationship between welfare benefits and single mother employment generalizes across countries. This study combines data from the European Union Labour Force Survey and the U.S. Current Population Survey (1992-2015) into one of the largest samples of single mothers ever, testing the relationships between welfare generosity and single mothers' employment and work hours. We find no consistent evidence of a negative relationship between welfare generosity and single mother employment outcomes. Rather, we find tremendous cross-national heterogeneity, which does not clearly correspond to well-known institutional variations. Our findings demonstrate the limitations of single country studies and the pervasive, salient interactions between institutional contexts and social policies.}, language = {en} } @misc{Bartenwerfer2022, type = {Master Thesis}, author = {Bartenwerfer, Dorothea}, title = {Technische Fachr{\"a}ume an Grundschulen}, doi = {10.25932/publishup-56293}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-562932}, school = {Universit{\"a}t Potsdam}, pages = {87}, year = {2022}, abstract = {Barrierefreiheit im Sinne (r{\"a}umlicher) Anpassung an heterogene Sch{\"u}lerschaften wurde bislang kaum an Schulen bzw. konkret im Technikunterricht erforscht. In dieser Arbeit wurden 5 Potsdamer Grundschulen unter dem Siegel „Schule des gemeinsamen Lernens" unter dem Aspekt der Barrierefreiheit in technischen Fachr{\"a}umen untersucht. Die Arbeit erfasst den Ist-Zustand {\"u}ber Einrichtung und Ausstattung technischer Fachr{\"a}ume an oben genannten Potsdamer Schulen und zeigt gleichzeitig verschiedene Fachraumkonzepte auf. Hierzu wurden technische Fachr{\"a}ume zum einen auf barrierefreie Elemente untersucht und zum anderen von WAT-Fachlehrkr{\"a}ften in Hinblick auf ihre Barrierefreiheit bewertet.}, language = {de} }