@phdthesis{Lenz2016,
  author    = {Lenz, Josefine},
  title     = {Thermokarst dynamics in central-eastern Beringia},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-101364},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XII, 128, A-47},
  year      = {2016},
  abstract  = {Widespread landscape changes are presently observed in the Arctic and are most likely to accelerate in the future, in particular in permafrost regions which are sensitive to climate warming. To assess current and future developments, it is crucial to understand past environmental dynamics in these landscapes. Causes and interactions of environmental variability can hardly be resolved by instrumental records covering modern time scales. However, long-term environmental variability is recorded in paleoenvironmental archives. Lake sediments are important archives that allow reconstruction of local limnogeological processes as well as past environmental changes driven directly or indirectly by climate dynamics. This study aims at reconstructing Late Quaternary permafrost and thermokarst dynamics in central-eastern Beringia, the terrestrial land mass connecting Eurasia and North America during glacial sea-level low stands. In order to investigate development, processes and influence of thermokarst dynamics, several sediment cores from extant lakes and drained lake basins were analyzed to answer the following research questions: 1. When did permafrost degradation and thermokarst lake development take place and what were enhancing and inhibiting environmental factors? 2. What are the dominant processes during thermokarst lake development and how are they reflected in proxy records? 3. How did, and still do, thermokarst dynamics contribute to the inventory and properties of organic matter in sediments and the carbon cycle? Methods applied in this study are based upon a multi-proxy approach combining sedimentological, geochemical, geochronological, and micropaleontological analyses, as well as analyses of stable isotopes and hydrochemistry of pore-water and ice. Modern field observations of water quality and basin morphometrics complete the environmental investigations. The investigated sediment cores reveal permafrost degradation and thermokarst dynamics on different time scales. The analysis of a sediment core from GG basin on the northern Seward Peninsula (Alaska) shows prevalent terrestrial accumulation of yedoma throughout the Early to Mid Wisconsin with intermediate wet conditions at around 44.5 to 41.5 ka BP. This first wetland development was terminated by the accumulation of a 1-meter-thick airfall tephra most likely originating from the South Killeak Maar eruption at 42 ka BP. A depositional hiatus between 22.5 and 0.23 ka BP may indicate thermokarst lake formation in the surrounding of the site which forms a yedoma upland till today. The thermokarst lake forming GG basin initiated 230 ± 30 cal a BP and drained in Spring 2005 AD. Four years after drainage the lake talik was still unfrozen below 268 cm depth. A permafrost core from Mama Rhonda basin on the northern Seward Peninsula preserved a full lacustrine record including several lake phases. The first lake generation developed at 11.8 cal ka BP during the Lateglacial-Early Holocene transition; its old basin (Grandma Rhonda) is still partially preserved at the southern margin of the study basin. Around 9.0 cal ka BP a shallow and more dynamic thermokarst lake developed with actively eroding shorelines and potentially intermediate shallow water or wetland phases (Mama Rhonda). Mama Rhonda lake drainage at 1.1 cal ka BP was followed by gradual accumulation of terrestrial peat and top-down refreezing of the lake talik. A significant lower organic carbon content was measured in Grandma Rhonda deposits (mean TOC of 2.5 wt\%) than in Mama Rhonda deposits (mean TOC of 7.9 wt\%) highlighting the impact of thermokarst dynamics on biogeochemical cycling in different lake generations by thawing and mobilization of organic carbon into the lake system. Proximal and distal sediment cores from Peatball Lake on the Arctic Coastal Plain of Alaska revealed young thermokarst dynamics since about 1,400 years along a depositional gradient based on reconstructions from shoreline expansion rates and absolute dating results. After its initiation as a remnant pond of a previous drained lake basin, a rapidly deepening lake with increasing oxygenation of the water column is evident from laminated sediments, and higher Fe/Ti and Fe/S ratios in the sediment. The sediment record archived characterizing shifts in depositional regimes and sediment sources from upland deposits and re-deposited sediments from drained thaw lake basins depending on the gradually changing shoreline configuration. These changes are evident from alternating organic inputs into the lake system which highlights the potential for thermokarst lakes to recycle old carbon from degrading permafrost deposits of its catchment. The lake sediment record from Herschel Island in the Yukon (Canada) covers the full Holocene period. After its initiation as a thermokarst lake at 11.7 cal ka BP and intense thermokarst activity until 10.0 cal ka BP, the steady sedimentation was interrupted by a depositional hiatus at 1.6 cal ka BP which likely resulted from lake drainage or allochthonous slumping due to collapsing shore lines. The specific setting of the lake on a push moraine composed of marine deposits is reflected in the sedimentary record. Freshening of the maturing lake is indicated by decreasing electrical conductivity in pore-water. Alternation of marine to freshwater ostracods and foraminifera confirms decreasing salinity as well but also reflects episodical re-deposition of allochthonous marine sediments. Based on permafrost and lacustrine sediment records, this thesis shows examples of the Late Quaternary evolution of typical Arctic permafrost landscapes in central-eastern Beringia and the complex interaction of local disturbance processes, regional environmental dynamics and global climate patterns. This study confirms that thermokarst lakes are important agents of organic matter recycling in complex and continuously changing landscapes.},
  language  = {en}
}
@phdthesis{Brauer2016,
  author    = {Brauer, Doroth{\´e}e},
  title     = {Chemo-kinematic constraints on Milky Way models from the spectroscopic surveys SEGUE \& RAVE},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-403968},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vii, 197},
  year      = {2016},
  abstract  = {The Milky Way is only one out of billions of galaxies in the universe. However, it is a special galaxy because it allows to explore the main mechanisms involved in its evolution and formation history by unpicking the system star-by-star. Especially, the chemical fingerprints of its stars provide clues and evidence of past events in the Galaxy's lifetime. These information help not only to decipher the current structure and building blocks of the Milky Way, but to learn more about the general formation process of galaxies. In the past decade a multitude of stellar spectroscopic Galactic surveys have scanned millions of stars far beyond the rim of the solar neighbourhood. The obtained spectroscopic information provide unprecedented insights to the chemo-dynamics of the Milky Way. In addition analytic models and numerical simulations of the Milky Way provide necessary descriptions and predictions suited for comparison with observations in order to decode the physical properties that underlie the complex system of the Galaxy. In the thesis various approaches are taken to connect modern theoretical modelling of galaxy formation and evolution with observations from Galactic stellar surveys. With its focus on the chemo-kinematics of the Galactic disk this work aims to determine new observational constraints on the formation of the Milky Way providing also proper comparisons with two different models. These are the population synthesis model TRILEGAL based on analytical distribution functions, which aims to simulate the number and distribution of stars in the Milky Way and its different components, and a hybrid model (MCM) that combines an N-body simulation of a Milky Way like galaxy in the cosmological framework with a semi-analytic chemical evolution model for the Milky Way. The major observational data sets in use come from two surveys, namely the "Radial Velocity Experiment" (RAVE) and the "Sloan Extension for Galactic Understanding and Exploration" (SEGUE). In the first approach the chemo-kinematic properties of the thin and thick disk of the Galaxy as traced by a selection of about 20000 SEGUE G-dwarf stars are directly compared to the predictions by the MCM model. As a necessary condition for this, SEGUE's selection function and its survey volume are evaluated in detail to correct the spectroscopic observations for their survey specific selection biases. Also, based on a Bayesian method spectro-photometric distances with uncertainties below 15\% are computed for the selection of SEGUE G-dwarfs that are studied up to a distance of 3 kpc from the Sun. For the second approach two synthetic versions of the SEGUE survey are generated based on the above models. The obtained synthetic stellar catalogues are then used to create mock samples best resembling the compiled sample of observed SEGUE G-dwarfs. Generally, mock samples are not only ideal to compare predictions from various models. They also allow validation of the models' quality and improvement as with this work could be especially achieved for TRILEGAL. While TRILEGAL reproduces the statistical properties of the thin and thick disk as seen in the observations, the MCM model has shown to be more suitable in reproducing many chemo-kinematic correlations as revealed by the SEGUE stars. However, evidence has been found that the MCM model may be missing a stellar component with the properties of the thick disk that the observations clearly show. While the SEGUE stars do indicate a thin-thick dichotomy of the stellar Galactic disk in agreement with other spectroscopic stellar studies, no sign for a distinct metal-poor disk is seen in the MCM model. Usually stellar spectroscopic surveys are limited to a certain volume around the Sun covering different regions of the Galaxy's disk. This often prevents to obtain a global view on the chemo-dynamics of the Galactic disk. Hence, a suitable combination of stellar samples from independent surveys is not only useful for the verification of results but it also helps to complete the picture of the Milky Way. Therefore, the thesis closes with a comparison of the SEGUE G-dwarfs and a sample of RAVE giants. The comparison reveals that the chemo-kinematic relations agree in disk regions where the samples of both surveys show a similar number of stars. For those parts of the survey volumes where one of the surveys lacks statistics they beautifully complement each other. This demonstrates that the comparison of theoretical models on the one side, and the combined observational data gathered by multiple surveys on the other side, are key ingredients to understand and disentangle the structure and formation history of the Milky Way.},
  language  = {en}
}
@phdthesis{Ulaganathan2016,
  author    = {Ulaganathan, Vamseekrishna},
  title     = {Molecular fundamentals of foam fractionation},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-94263},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 136},
  year      = {2016},
  abstract  = {Foam fractionation of surfactant and protein solutions is a process dedicated to separate surface active molecules from each other due to their differences in surface activities. The process is based on forming bubbles in a certain mixed solution followed by detachment and rising of bubbles through a certain volume of this solution, and consequently on the formation of a foam layer on top of the solution column. Therefore, systematic analysis of this whole process comprises of at first investigations dedicated to the formation and growth of single bubbles in solutions, which is equivalent to the main principles of the well-known bubble pressure tensiometry. The second stage of the fractionation process includes the detachment of a single bubble from a pore or capillary tip and its rising in a respective aqueous solution. The third and final stage of the process is the formation and stabilization of the foam created by these bubbles, which contains the adsorption layers formed at the growing bubble surface, carried up and gets modified during the bubble rising and finally ends up as part of the foam layer. Bubble pressure tensiometry and bubble profile analysis tensiometry experiments were performed with protein solutions at different bulk concentrations, solution pH and ionic strength in order to describe the process of accumulation of protein and surfactant molecules at the bubble surface. The results obtained from the two complementary methods allow understanding the mechanism of adsorption, which is mainly governed by the diffusional transport of the adsorbing protein molecules to the bubble surface. This mechanism is the same as generally discussed for surfactant molecules. However, interesting peculiarities have been observed for protein adsorption kinetics at sufficiently short adsorption times. First of all, at short adsorption times the surface tension remains constant for a while before it decreases as expected due to the adsorption of proteins at the surface. This time interval is called induction time and it becomes shorter with increasing protein bulk concentration. Moreover, under special conditions, the surface tension does not stay constant but even increases over a certain period of time. This so-called negative surface pressure was observed for BCS and BLG and discussed for the first time in terms of changes in the surface conformation of the adsorbing protein molecules. Usually, a negative surface pressure would correspond to a negative adsorption, which is of course impossible for the studied protein solutions. The phenomenon, which amounts to some mN/m, was rather explained by simultaneous changes in the molar area required by the adsorbed proteins and the non-ideality of entropy of the interfacial layer. It is a transient phenomenon and exists only under dynamic conditions. The experiments dedicated to the local velocity of rising air bubbles in solutions were performed in a broad range of BLG concentration, pH and ionic strength. Additionally, rising bubble experiments were done for surfactant solutions in order to validate the functionality of the instrument. It turns out that the velocity of a rising bubble is much more sensitive to adsorbing molecules than classical dynamic surface tension measurements. At very low BLG or surfactant concentrations, for example, the measured local velocity profile of an air bubble is changing dramatically in time scales of seconds while dynamic surface tensions still do not show any measurable changes at this time scale. The solution's pH and ionic strength are important parameters that govern the measured rising velocity for protein solutions. A general theoretical description of rising bubbles in surfactant and protein solutions is not available at present due to the complex situation of the adsorption process at a bubble surface in a liquid flow field with simultaneous Marangoni effects. However, instead of modelling the complete velocity profile, new theoretical work has been started to evaluate the maximum values in the profile as characteristic parameter for dynamic adsorption layers at the bubble surface more quantitatively. The studies with protein-surfactant mixtures demonstrate in an impressive way that the complexes formed by the two compounds change the surface activity as compared to the original native protein molecules and therefore lead to a completely different retardation behavior of rising bubbles. Changes in the velocity profile can be interpreted qualitatively in terms of increased or decreased surface activity of the formed protein-surfactant complexes. It was also observed that the pH and ionic strength of a protein solution have strong effects on the surface activity of the protein molecules, which however, could be different on the rising bubble velocity and the equilibrium adsorption isotherms. These differences are not fully understood yet but give rise to discussions about the structure of protein adsorption layer under dynamic conditions or in the equilibrium state. The third main stage of the discussed process of fractionation is the formation and characterization of protein foams from BLG solutions at different pH and ionic strength. Of course a minimum BLG concentration is required to form foams. This minimum protein concentration is a function again of solution pH and ionic strength, i.e. of the surface activity of the protein molecules. Although at the isoelectric point, at about pH 5 for BLG, the hydrophobicity and hence the surface activity should be the highest, the concentration and ionic strength effects on the rising velocity profile as well as on the foamability and foam stability do not show a maximum. This is another remarkable argument for the fact that the interfacial structure and behavior of BLG layers under dynamic conditions and at equilibrium are rather different. These differences are probably caused by the time required for BLG molecules to adapt respective conformations once they are adsorbed at the surface. All bubble studies described in this work refer to stages of the foam fractionation process. Experiments with different systems, mainly surfactant and protein solutions, were performed in order to form foams and finally recover a solution representing the foamed material. As foam consists to a large extent of foam lamella - two adsorption layers with a liquid core - the concentration in a foamate taken from foaming experiments should be enriched in the stabilizing molecules. For determining the concentration of the foamate, again the very sensitive bubble rising velocity profile method was applied, which works for any type of surface active materials. This also includes technical surfactants or protein isolates for which an accurate composition is unknown.},
  language  = {en}
}
@book{Martins2016,
  author    = {Martins, Ansgar},
  title     = {Adorno und die Kabbala},
  series = {Pri ha-Pardes},
  journal   = {Pri ha-Pardes},
  number    = {9},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-369-5},
  issn      = {1863-7442},
  doi       = {10.25932/publishup-9120},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-91201},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {211},
  year      = {2016},
  abstract  = {Im neunten Band der Reihe geht Ansgar Martins kabbalistischen Spuren in der Philosophie Theodor W. Adornos (1903-1969) nach. Der Frankfurter Gesellschaftskritiker griff im Rahmen seines radikalen materialistischen Projekts gleichwohl auch auf ‚theologische' Deutungsfiguren zur{\"u}ck. Vermittelt durch den gemeinsamen Freund Walter Benjamin (1892-1940) stieß Adorno dabei auf das Werk des Kabbala-Forschers Gershom Scholem (1897-1982). Zwischen Frankfurt und Jerusalem entwickelte sich eine lebenslange Korrespondenz. F{\"u}r Adorno erscheint vor dem Hintergrund l{\"u}ckenloser kapitalistischer Vergesellschaftung jede religi{\"o}se Sinngebung in der Moderne als unm{\"o}glich. Der Tradition der j{\"u}dischen Mystik schreibt er hingegen eine innere Affinit{\"a}t zu dieser hoffnungslosen Logik des ‚Verfalls' zu. Sie scheint ihm zur unumg{\"a}nglichen S{\"a}kularisierung religi{\"o}ser Gehalte aufzufordern. Adornos kabbalistische Marginalien beziehen einen breiten Horizont j{\"u}disch-messianischer Ideen ein. Er verleugnet dabei nie, dass es ihm um eine sehr diesseite Verwirklichung geoffenbarter Heilsversprechen zu tun ist: Transzendenz sei als erf{\"u}llte Immanenz, als verwirklichte Utopie zu denken. In diesem Anliegen sieht Adorno selbst jedoch gerade seine {\"U}bereinstimmung mit der Kabbala. Adornos kabbalistische Motive, die auf Scholems Forschungen zur{\"u}ckgehen, werden hier ausf{\"u}hrlich an seinen Schriften und Vorlesungen untersucht. In seinem Verst{\"a}ndnis der philosophischen Tradition sowie im Modell der Metaphysischen Erfahrung suchte er etwa explizit Anschluss an Deutungen der Kabbala: Das unerreichbare Urbild der Philosophie sei die Interpretation der geoffenbarten Schrift. Wie s{\"a}kularisierte heilige Texte wurden Werke von Beethoven, Goethe, Kafka oder Sch{\"o}nberg so zum Anlass f{\"u}r ‚mystische' Interpretationen. Deren detaillierte Untersuchung erlaubt, das viel beschworene j{\"u}dische Erbe von Adornos Philosophie zu konkretisieren und bedenkenswerte Einzelheiten von der Negativen Dialektik zur {\"A}sthetik in den Blick zu nehmen.},
  language  = {de}
}
@phdthesis{Friese2016,
  author    = {Friese, Viviane A.},
  title     = {Solvato-, vapo, mechanochromic and luminescent behavior of Rhodium, Platinum and Gold complexes and their coordination polymers},
  school      = {Universit{\"a}t Potsdam},
  pages     = {100 S.},
  year      = {2016},
  language  = {en}
}
@book{EmrichGassmannHerrmannetal.2016,
  author    = {Emrich, Eike and Gassmann, Freya and Herrmann, Konstantin and Koch, Michael and Meyer, Wolfgang},
  title     = {Die Universit{\"a}t Potsdam in sozio{\"o}konomischer Perspektive},
  editor    = {Emrich, Eike and Gassmann, Freya and Herrmann, Konstantin},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  isbn      = {978-3-86956-367-1},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-90200},
  publisher      = {Universit{\"a}t Potsdam},
  pages     = {409},
  year      = {2016},
  abstract  = {Universit{\"a}ten erbringen wohlfahrtsf{\"o}rdernde Leistungen f{\"u}r die Gesellschaft, insbesondere indem sie Studierende ausbilden, {\"u}ber Forschung neues Wissen erzeugen sowie den Wissens- und Technologietransfer in Wirtschaft und Gesellschaft hinein betreiben. Die Erbringung dieser Leistungen wird erm{\"o}glicht durch eine gr{\"o}ßtenteils {\"o}ffentliche Finanzierung, die nicht nur in Zeiten wirtschaftlicher Krisen und Spargebote gerne hinterfragt wird. Die Politik ist daher ebenso wie die Hochschulen gut beraten, die Mittelzuweisungen immer wieder neu zu legitimieren. Die vorliegende Studie untersucht die sozio{\"o}konomischen Effekte der Universit{\"a}t Potsdam und schließt so vorhandene Informationsl{\"u}cken. Die Autoren zeigen, dass auch indirekte und unerwartete Effekte eine große Rolle spielen k{\"o}nnen, was die Wirkung einer Universit{\"a}t auf Wirtschaft und Wohlstand angeht.},
  language  = {de}
}