@article{VaidyaSchmidtRakowskietal.2021, author = {Vaidya, Shrijana and Schmidt, Marten and Rakowski, Peter and Bonk, Norbert and Verch, Gernot and Augustin, J{\"u}rgen and Sommer, Michael and Hoffmann, Mathias}, title = {A novel robotic chamber system allowing to accurately and precisely determining spatio-temporal CO2 flux dynamics of heterogeneous croplands}, series = {Agricultural and forest meteorology}, volume = {296}, journal = {Agricultural and forest meteorology}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0168-1923}, doi = {10.1016/j.agrformet.2020.108206}, pages = {9}, year = {2021}, abstract = {The precise and accurate assessment of carbon dioxide (CO2) exchange is crucial to identify terrestrial carbon (C) sources and sinks and for evaluating their role within the global C budget. The substantial uncertainty in disentangling the management and soil impact on measured CO2 fluxes are largely ignored especially in cropland. The reasons for this lies in the limitation of the widely used eddy covariance as well as manual and automatic chamber systems, which either account for short-term temporal variability or small-scale spatial heterogeneity, but barely both. To address this issue, we developed a novel robotic chamber system allowing for dozens of spatial measurement repetitions, thus enabling CO2 exchange measurements in a sufficient temporal and high small-scale spatial resolution. The system was tested from 08th July to 09th September 2019 at a heterogeneous field (100 m x 16 m), located within the hummocky ground moraine landscape of northeastern Germany (CarboZALF-D). The field is foreseen for a longer-term block trial manipulation experiment extending over three erosion induced soil types and was covered with spring barley. Measured fluxes of nighttime ecosystem respiration (R-eco) and daytime net ecosystem exchange (NEE) showed distinct temporal patterns influenced by crop phenology, weather conditions and management practices. Similarly, we found clear small-scale spatial differences in cumulated (gap-filled) R-eco, gross primary productivity (GPP) and NEE fluxes affected by the three distinct soil types. Additionally, spatial patterns induced by former management practices and characterized by differences in soil pH and nutrition status (P and K) were also revealed between plots within each of the three soil types, which allowed compensating for prior to the foreseen block trial manipulation experiment. The results underline the great potential of the novel robotic chamber system, which not only detects short-term temporal CO2 flux dynamics but also reflects the impact of small-scale spatial heterogeneity.}, language = {en} } @article{TillmannKroemkerHornetal.2018, author = {Tillmann, Alexander and Kr{\"o}mker, Detlef and Horn, Florian and Gattinger, Thorsten}, title = {Analysing \& Predicting Students Performance in an Introductory Computer Science Course}, series = {Commentarii informaticae didacticae}, journal = {Commentarii informaticae didacticae}, number = {12}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-416307}, pages = {29 -- 45}, year = {2018}, abstract = {Students of computer science studies enter university education with very different competencies, experience and knowledge. 145 datasets collected of freshmen computer science students by learning management systems in relation to exam outcomes and learning dispositions data (e. g. student dispositions, previous experiences and attitudes measured through self-reported surveys) has been exploited to identify indicators as predictors of academic success and hence make effective interventions to deal with an extremely heterogeneous group of students.}, language = {en} } @article{StedingKempkaKuehn2021, author = {Steding, Svenja and Kempka, Thomas and K{\"u}hn, Michael}, title = {How insoluble inclusions and intersecting layers affect the leaching process within potash seams}, series = {Applied Sciences : open access journal}, volume = {11}, journal = {Applied Sciences : open access journal}, number = {19}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app11199314}, pages = {21}, year = {2021}, abstract = {Potash seams are a valuable resource containing several economically interesting, but also highly soluble minerals. In the presence of water, uncontrolled leaching can occur, endangering subsurface mining operations. In the present study, the influence of insoluble inclusions and intersecting layers on leaching zone evolution was examined by means of a reactive transport model. For that purpose, a scenario analysis was carried out, considering different rock distributions within a carnallite-bearing potash seam. The results show that reaction-dominated systems are not affected by heterogeneities at all, whereas transport-dominated systems exhibit a faster advance in homogeneous rock compositions. In return, the ratio of permeated rock in vertical direction is higher in heterogeneous systems. Literature data indicate that most natural potash systems are transport-dominated. Accordingly, insoluble inclusions and intersecting layers can usually be seen as beneficial with regard to reducing hazard potential as long as the mechanical stability of leaching zones is maintained. Thereby, the distribution of insoluble areas is of minor impact unless an inclined, intersecting layer occurs that accelerates leaching zone growth in one direction. Moreover, it is found that the saturation dependency of dissolution rates increases the growth rate in the long term, and therefore must be considered in risk assessments.}, language = {en} } @article{SchallGossnerHeinrichsetal.2017, author = {Schall, Peter and Gossner, Martin M. and Heinrichs, Steffi and Fischer, Markus and Boch, Steffen and Prati, Daniel and Jung, Kirsten and Baumgartner, Vanessa and Blaser, Stefan and B{\"o}hm, Stefan and Buscot, Francois and Daniel, Rolf and Goldmann, Kezia and Kaiser, Kristin and Kahl, Tiemo and Lange, Markus and M{\"u}ller, J{\"o}rg Hans and Overmann, J{\"o}rg and Renner, Swen C. and Schulze, Ernst-Detlef and Sikorski, Johannes and Tschapka, Marco and T{\"u}rke, Manfred and Weisser, Wolfgang W. and Wemheuer, Bernd and Wubet, Tesfaye and Ammer, Christian}, title = {The impact of even-aged and uneven-aged forest management on regional biodiversity of multiple taxa in European beech forests}, series = {Journal of applied ecology : an official journal of the British Ecological Society}, volume = {55}, journal = {Journal of applied ecology : an official journal of the British Ecological Society}, number = {1}, publisher = {Wiley}, address = {Hoboken}, issn = {0021-8901}, doi = {10.1111/1365-2664.12950}, pages = {267 -- 278}, year = {2017}, abstract = {1. For managed temperate forests, conservationists and policymakers favour fine-grained uneven-aged (UEA) management over more traditional coarse-grained even-aged (EA) management, based on the assumption that within-stand habitat heterogeneity enhances biodiversity. There is, however, little empirical evidence to support this assumption. We investigated for the first time how differently grained forest management systems affect the biodiversity of multiple above- and below-ground taxa across spatial scales. 2. We sampled 15 taxa of animals, plants, fungi and bacteria within the largest contiguous beech forest landscape of Germany and classified them into functional groups. Selected forest stands have been managed for more than a century at different spatial grains. The EA (coarse-grained management) and UEA (fine-grained) forests are comparable in spatial arrangement, climate and soil conditions. These were compared to forests of a nearby national park that have been unmanaged for at least 20years. We used diversity accumulation curves to compare -diversity for Hill numbers D-0 (species richness), D-1 (Shannon diversity) and D-2 (Simpson diversity) between the management systems. Beta diversity was quantified as multiple-site dissimilarity. 3. Gamma diversity was higher in EA than in UEA forests for at least one of the three Hill numbers for six taxa (up to 77\%), while eight showed no difference. Only bacteria showed the opposite pattern. Higher -diversity in EA forests was also found for forest specialists and saproxylic beetles. 4. Between-stand -diversity was higher in EA than in UEA forests for one-third (all species) and half (forest specialists) of all taxa, driven by environmental heterogeneity between age-classes, while -diversity showed no directional response across taxa or for forest specialists. 5. Synthesis and applications. Comparing EA and uneven-aged forest management in Central European beech forests, our results show that a mosaic of different age-classes is more important for regional biodiversity than high within-stand heterogeneity. We suggest reconsidering the current trend of replacing even-aged management in temperate forests. Instead, the variability of stages and stand structures should be increased to promote landscape-scale biodiversity.}, language = {en} } @misc{RingelSomogyvariJalalietal.2019, author = {Ringel, Lisa Maria and Somogyv{\´a}ri, M{\´a}rk and Jalali, Mohammadreza and Bayer, Peter}, title = {Comparison of hydraulic and tracer tomography for discrete fracture network inversion}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {922}, issn = {1866-8372}, doi = {10.25932/publishup-44261}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-442616}, pages = {19}, year = {2019}, abstract = {Fractures serve as highly conductive preferential flow paths for fluids in rocks, which are difficult to exactly reconstruct in numerical models. Especially, in low-conductive rocks, fractures are often the only pathways for advection of solutes and heat. The presented study compares the results from hydraulic and tracer tomography applied to invert a theoretical discrete fracture network (DFN) that is based on data from synthetic cross-well testing. For hydraulic tomography, pressure pulses in various injection intervals are induced and the pressure responses in the monitoring intervals of a nearby observation well are recorded. For tracer tomography, a conservative tracer is injected in different well levels and the depth-dependent breakthrough of the tracer is monitored. A recently introduced transdimensional Bayesian inversion procedure is applied for both tomographical methods, which adjusts the fracture positions, orientations, and numbers based on given geometrical fracture statistics. The used Metropolis-Hastings-Green algorithm is refined by the simultaneous estimation of the measurement error's variance, that is, the measurement noise. Based on the presented application to invert the two-dimensional cross-section between source and the receiver well, the hydraulic tomography reveals itself to be more suitable for reconstructing the original DFN. This is based on a probabilistic representation of the inverted results by means of fracture probabilities.}, language = {en} } @article{RingelSomogyvariJalalietal.2019, author = {Ringel, Lisa Maria and Somogyv{\´a}ri, M{\´a}rk and Jalali, Mohammadreza and Bayer, Peter}, title = {Comparison of hydraulic and tracer tomography for discrete fracture network inversion}, series = {Geosciences}, volume = {9}, journal = {Geosciences}, number = {6}, publisher = {MDPI}, address = {Basel}, issn = {2076-3263}, doi = {10.3390/geosciences9060274}, pages = {17}, year = {2019}, abstract = {Fractures serve as highly conductive preferential flow paths for fluids in rocks, which are difficult to exactly reconstruct in numerical models. Especially, in low-conductive rocks, fractures are often the only pathways for advection of solutes and heat. The presented study compares the results from hydraulic and tracer tomography applied to invert a theoretical discrete fracture network (DFN) that is based on data from synthetic cross-well testing. For hydraulic tomography, pressure pulses in various injection intervals are induced and the pressure responses in the monitoring intervals of a nearby observation well are recorded. For tracer tomography, a conservative tracer is injected in different well levels and the depth-dependent breakthrough of the tracer is monitored. A recently introduced transdimensional Bayesian inversion procedure is applied for both tomographical methods, which adjusts the fracture positions, orientations, and numbers based on given geometrical fracture statistics. The used Metropolis-Hastings-Green algorithm is refined by the simultaneous estimation of the measurement error's variance, that is, the measurement noise. Based on the presented application to invert the two-dimensional cross-section between source and the receiver well, the hydraulic tomography reveals itself to be more suitable for reconstructing the original DFN. This is based on a probabilistic representation of the inverted results by means of fracture probabilities.}, language = {en} } @phdthesis{Naumann2008, author = {Naumann, Siglinde}, title = {Heterogenit{\"a}t und Bildungsprozesse in b{\"u}rgerschaftlichen Initiativen : eine empirische Studie zur Transformation konjunktiver Orientierungen}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-19784}, school = {Universit{\"a}t Potsdam}, year = {2008}, abstract = {In dieser qualitativ rekonstruktiven Studie wird an Hand der empirischen Rekonstruktion von Gruppendiskussionen der Fragestellung nachgegangen, welchen handlungsleitenden Orientierungen die Mitglieder der untersuchten Initiativen im Umgang mit ihrer Heterogenit{\"a}t folgen und wie diese Orientierungen mit Lern- beziehungsweise Bildungsprozessen korrespondieren. Diese Fragestellung ist mit unterschiedlichen theoretischen Kontexten verwoben. Zum Einen geht es hier um Heterogenit{\"a}t und Pluralit{\"a}t. Der Umgang mit Heterogenit{\"a}t und Pluralit{\"a}t gilt als eine zentrale Herausforderung in modernen stark ausdifferenzierten und hochkomplexen Gesellschaften, die mit fluiden mikro- und makrogesellschaftlichen Strukturen (vgl. Sch{\"a}ffter 1998) und vielf{\"a}ltigsten Formen kultureller Pluralit{\"a}t (vgl. Nohl 2006) einhergehen. Ein Reflexionsangebot f{\"u}r die erziehungswissenschaftliche Diskussion bietet die Denkfigur der egalit{\"a}ren Differenz. (Vgl. Prengel Ein Reflexionsangebot f{\"u}r die erziehungswissenschaftliche Diskussion bietet die Denkfigur der egalit{\"a}ren Differenz. Zum Anderen ist eine rekonstruktive Untersuchung b{\"u}rgerschaftlicher Initiativen nicht ohne Bezug zu ihrem zivilgesellschaftlichen Kontext zu denken. So sei hier stellvertretend f{\"u}r andere zeitdiagnostische {\"U}berlegungen auf Giddens Position (vgl. Giddens 1996) verwiesen, der die gesellschaftlichen Ver{\"a}nderungen in der reflexiven Moderne mit weitreichenden Prozessen des sozialen Wandels verbunden sieht. In dieser Studie wird im Anschluss an die strukturale Bildungstheorie von Marotzki (vgl. Marotzki 1990) zwischen Lern- und Bildungsprozessen unterschieden. Vor dem Hintergrund der Theorie Mannheims zu konjunktiven existentiellen Erfahrungen und der damit einhergehenden Seinsverbundenheit des Wissens (vgl. Mannheim 1980) werden diese Prozesse im Anschluss an Sch{\"a}ffers qualitative Studie zu generationenfundierten Bildungsprozessen (vgl. Sch{\"a}ffer 2003) als kollektiv fundierte Prozesse verstanden. Das von Karl Mannheim entwickelte Konzept des „konjunktiven Erfahrungsraums" (vgl. Mannheim 1980) wird im Anschluss an andere Studien der qualitativen Bildungsforschung (vgl. Sch{\"a}ffer 2003, Nohl 2006) f{\"u}r die Rekonstruktion von Bildungsprozessen genutzt, die auf der Transformation konjunktiver Erfahrungen beruhen. In der vorliegenden Studie werden die in den untersuchten Initiativen relevanten habituellen Muster des Umgangs mit Heterogenit{\"a}t rekonstruiert und ihre Bedeutung f{\"u}r Lern- und Bildungsprozesse zu erhellt. B{\"u}rgerschaftliche Initiativen werden als lebensweltliche Lernorte in den Blick genommen, mit der Auswertung nach der dokumentarischen Methode wird ein Verst{\"a}ndnis zu Grunde gelegt, dass auf die Verwobenheit gesellschaftlicher Strukturen mit dem Erleben der Akteure und damit den Prozessen der sozialen Genese von Interaktion und Identit{\"a}t verweist. (Vgl. Bohnsack 2003, Kubisch 2008)}, language = {de} } @article{Kruse2023, author = {Kruse, Julia}, title = {Entwicklung und Durchf{\"u}hrung eines Seminars zur F{\"o}rderung der Diagnosekompetenz von Lehramtsstudierenden der Grundschulp{\"a}dagogik Deutsch im Bereich der Lesefl{\"u}ssigkeit}, 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-61856}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-618562}, pages = {329 -- 342}, year = {2023}, abstract = {Die differenzierte und individuelle F{\"o}rderung der Lesefl{\"u}ssigkeit in heterogenen Gruppen erfordert ein hohes Maß an diagnostischer Kompetenz. Diese kann nicht allein durch die Vermittlung von Wissen gef{\"o}rdert werden, sondern muss zus{\"a}tzlich durch praxisnahe {\"U}bungen sukzessive ausgebildet werden. Um die Diagnosekompetenz von Masterstudierenden der Grundschulp{\"a}dagogik (Deutsch) an der Universit{\"a}t zu Potsdam zu f{\"o}rdern, wurde im Rahmen des Projekts PSI-Potsdam ein Seminar entwickelt und durchgef{\"u}hrt, das nach der Idee des Blended Learning mit digitalen {\"U}bungen angereichert ist und eine F{\"o}rderung der Diagnosekompetenz {\"u}ber einen l{\"a}ngeren Zeitraum gew{\"a}hrleisten soll. In dem Beitrag werden nach einer theoretischen Einf{\"u}hrung sowie einer Darlegung der Relevanz des Seminarkonzepts f{\"u}r Lehrkr{\"a}fte der Primarstufe Deutsch die Entwicklung und Einbettung der {\"U}bungstools im Seminar dargestellt sowie deren praktischer Einsatz diskutiert.}, language = {de} } @article{KoussoroplisWacker2016, author = {Koussoroplis, Apostolos-Manuel and Wacker, Alexander}, title = {Covariance modulates the effect of joint temperature and food variance on ectotherm life-history traits}, series = {Ecology letters}, volume = {19}, journal = {Ecology letters}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1461-023X}, doi = {10.1111/ele.12546}, pages = {143 -- 152}, year = {2016}, abstract = {Understanding animal performance in heterogeneous or variable environments is a central question in ecology. We combine modelling and experiments to test how temperature and food availability variance jointly affect life-history traits of ectotherms. The model predicts that as mean temperatures move away from the ectotherm's thermal optimum, the effect size of joint thermal and food variance should become increasingly sensitive to their covariance. Below the thermal optimum, performance should be positively correlated with food-temperature covariance and the opposite is predicted above it. At lower temperatures, covariance should determine whether food and temperature variance increases or decreases performance compared to constant conditions. Somewhat stronger than predicted, the covariance effect below the thermal optimum was confirmed experimentally on an aquatic ectotherm (Daphnia magna) exposed to diurnal food and temperature variance with different amounts of covariance. Our findings have important implications for understanding ectotherm responses to climate-driven alterations of thermal mean and variance.}, language = {en} } @misc{JeltschGrimmReegetal.2019, author = {Jeltsch, Florian and Grimm, Volker and Reeg, Jette and Schl{\"a}gel, Ulrike E.}, title = {Give chance a chance}, series = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam Mathematisch-Naturwissenschaftliche Reihe}, number = {742}, issn = {1866-8372}, doi = {10.25932/publishup-43532}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-435320}, 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{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} }