@phdthesis{Alawashra2024,
  author    = {Alawashra, Mahmoud},
  title     = {Plasma instabilities of TeV pair beams induced by blazars},
  doi       = {10.25932/publishup-63013},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-630131},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxi, 130},
  year      = {2024},
  abstract  = {Relativistic pair beams produced in the cosmic voids by TeV gamma rays from blazars are expected to produce a detectable GeV-scale cascade emission missing in the observations. The suppression of this secondary cascade implies either the deflection of the pair beam by intergalactic magnetic fields (IGMFs) or an energy loss of the beam due to the electrostatic beam-plasma instability. IGMF of femto-Gauss strength is sufficient to significantly deflect the pair beams reducing the flux of secondary cascade below the observational limits. A similar flux reduction may result in the absence of the IGMF from the beam energy loss by the instability before the inverse Compton cooling. This dissertation consists of two studies about the instability role in the evolution of blazar-induced beams. Firstly, we investigated the effect of sub-fG level IGMF on the beam energy loss by the instability. Considering IGMF with correlation lengths smaller than a few kpc, we found that such fields increase the transverse momentum of the pair beam particles, dramatically reducing the linear growth rate of the electrostatic instability and hence the energy-loss rate of the pair beam. Our results show that the IGMF eliminates beam plasma instability as an effective energy-loss agent at a field strength three orders of magnitude below that needed to suppress the secondary cascade emission by magnetic deflection. For intermediate-strength IGMF, we do not know a viable process to explain the observed absence of GeV-scale cascade emission and hence can be excluded. Secondly, we probed how the beam-plasma instability feeds back on the beam, using a realistic two-dimensional beam distribution. We found that the instability broadens the beam opening angles significantly without any significant energy loss, thus confirming a recent feedback study on a simplified one-dimensional beam distribution. However, narrowing diffusion feedback of the beam particles with Lorentz factors less than 1e6 might become relevant even though initially it is negligible. Finally, when considering the continuous creation of TeV pairs, we found that the beam distribution and the wave spectrum reach a new quasi-steady state, in which the scattering of beam particles persists and the beam opening angle may increase by a factor of hundreds. This new intrinsic scattering of the cascade can result in time delays of around ten years, thus potentially mimicking the IGMF deflection. Understanding the implications on the GeV cascade emission requires accounting for inverse Compton cooling and simulating the beam-plasma system at different points in the IGM.},
  language  = {en}
}
@phdthesis{Rubertus2024,
  author    = {Rubertus, Elina},
  title     = {Coarticulatory changes across childhood},
  doi       = {10.25932/publishup-63012},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-630123},
  school      = {Universit{\"a}t Potsdam},
  pages     = {X, 131},
  year      = {2024},
  abstract  = {The present dissertation investigates changes in lingual coarticulation across childhood in German-speaking children from three to nine years of age and adults. Coarticulation refers to the mismatch between the abstract phonological units and their seemingly commingled realization in continuous speech. Being a process at the intersection of phonology and phonetics, addressing its changes across childhood allows for insights in speech motor as well as phonological developments. Because specific predictions for changes in coarticulation across childhood can be derived from existing speech production models, investigating children's coarticulatory patterns can help us model human speech production. While coarticulatory changes may shed light on some of the central questions of speech production development, previous studies on the topic were sparse and presented a puzzling picture of conflicting findings. One of the reasons for this lack is the difficulty in articulatory data acquisition in a young population. Within the research program this dissertation is embedded in, we accepted this challenge and successfully set up the hitherto largest corpus of articulatory data from children using ultrasound tongue imaging. In contrast to earlier studies, a high number of participants in tight age cohorts across a wide age range and a thoroughly controlled set of pseudowords allowed for statistically powerful investigations of a process known as variable and complicated to track. The specific focus of my studies is on lingual vocalic coarticulation as measured in the horizontal position of the highest point of the tongue dorsum. Based on three studies on a) anticipatory coarticulation towards the left, b) carryover coarticulation towards the right side of the utterance, and c) anticipatory coarticulatory extent in repeated versus read aloud speech, I deduct the following main theses: 1. Maturing speech motor control is responsible for some developmental changes in coarticulation. 2. Coarticulation can be modeled as the coproduction of articulatory gestures. 3. The developmental change in coarticulation results from a decrease of vocalic activation width.},
  language  = {en}
}
@phdthesis{Shipova2024,
  author    = {Shipova, Evgeniya},
  title     = {Formal analysis of {\`e}to-clefts in Russian: syntax and semantics},
  doi       = {10.25932/publishup-63014},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-630149},
  school      = {Universit{\"a}t Potsdam},
  pages     = {219},
  year      = {2024},
  abstract  = {{\`E}to-clefts are Russian focus constructions with the demonstrative pronoun {\`e}to 'this' at the beginning: "{\`E}to Mark vyigral gonku" ("It was Mark who won the race"). They are often being compared with English it-clefts, German es-clefts, as well as the corresponding focus-background structures in other languages. In terms of semantics, {\`e}to-clefts have two important properties which are cross-linguistically typical for clefts: existence presupposition ("Someone won the race") and exhaustivity ("Nobody except Mark won the race"). However, the exhaustivity effects are not as strong as exhaustivity effects in structures with the exclusive only and require more research. At the same time, the question if the syntactic structure of {\`e}to-clefts matches the biclausal structure of English and German clefts, remains open. There are arguments in favor of biclausality, as well as monoclausality. Besides, there is no consistency regarding the status of {\`e}to itself. Finally, the information structure of {\`e}to-clefts has remained underexplored in the existing literature. This research investigates the information-structural, syntactic, and semantic properties of Russian clefts, both theoretically (supported by examples from Russian text corpora and judgments from native speakers) and experimentally. It is determined which desired changes in the information structure motivate native speakers to choose an {\`e}to-cleft and not the canonical structure or other focus realization tools. Novel syntactic tests are conducted to find evidence for bi-/monoclausality of {\`e}to-clefts, as well as for base-generation or movement of the cleft pivot. It is hypothesized that {\`e}to has a certain important function in clefts, and its status is investigated. Finally, new experiments on the nature of exhaustivity in {\`e}to-clefts are conducted. They allow for direct cross-linguistic comparison, using an incremental-information paradigm with truth-value judgments. In terms of information structure, this research makes a new proposal that presents {\`e}to-clefts as structures with an inherent focus-background bipartitioning. Even though {\`e}to-clefts are used in typical focus contexts, evidence was found that {\`e}to-clefts (as well as Russian thetic clefts) allow for both new information focus and contrastive focus. {\`E}to-clefts are pragmatically acceptable when a singleton answer to the implied question is expected (e.g. "It was Mark who won the race" but not "It was Mark who came to the party"). Importantly, {\`e}to in Russian clefts is neither dummy, nor redundant, but is a topic expression; conveys familiarity which triggers existence presupposition; refers to an instantiated event, or a known/perceivable situation; finally, {\`e}to plays an important role in the spoken language as a tool for speech coherency and a focus marker. In terms of syntax, this research makes a new monoclausal proposal and shows evidence that the cleft pivot undergoes movement to the left peripheral position. {\`E}to is proposed to be TopP. Finally, in terms of semantics, a novel cross-linguistic evaluation of Russian clefts is made. Experiments show that the exhaustivity inference in {\`e}to-clefts is not robust. Participants used different strategies in resolving exhaustivity, falling into 2 groups: one group considered {\`e}to-clefts exhaustive, while another group considered them non-exhaustive. Hence, there is evidence for the pragmatic nature of exhaustivity in {\`e}to-clefts. The experimental results for {\`e}to-clefts are similar to the experimental results for clefts in German, French and Akan. It is concluded that speakers use different tools available in their languages to produce structures with similar interpretive properties.},
  language  = {en}
}
@phdthesis{JimenezAlvaro2023,
  author    = {Jim{\´e}nez {\´A}lvaro, Eliana},
  title     = {An{\´a}lisis neotect{\´o}nico y lito-tefroestratigr{\´a}fico de los grandes movimientos en masa asociados al fallamiento activo de la cuenca intermontana Quito-Guayllabamba, Ecuador},
  doi       = {10.25932/publishup-62220},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-622209},
  school      = {Universit{\"a}t Potsdam},
  pages     = {195},
  year      = {2023},
  abstract  = {Within the Quito-Guayllabamba intermontane basin of Ecuador, five unusually large colluvial deposits of ancient landslides have been identified and analyzed in this study. The voluminous rotational MM-5 Guayllabamba landslide is the largest one, with a volume of 1183 million m3. The mega debris-avalanches MM-1 Conocoto, MM-3 Oyacoto, and MM-4 San Francisco were originally triggered by an initial rupture that was associated with a rotational landslide, the corresponding deposits have volumes between 399 to 317 million m3. Finally, the deposit with the smallest volume, the MM-2 Bat{\´a}n rotational landslide and debris fall, has a volume of 8,7 million m3. In this thesis, a detailed study of these large mass movements was carried out using neotectonic and litho-tephrostratigraphic methods to understand the geological and geomorphological boundary conditions that might have been relevant for triggering such mass movements. The neotectonic part of the study was based on the qualitative and quantitative geomorphic analysis of these large mass-movement deposits through the structural characterization of anticlines located east of the Quito sub-basin and their collapsed flanks that constitute the break-off areas. This part of the analysis was furthermore supported by the application of different morphometric indices to reveal tectonically forced landscape evolution processes that may have aided mass-movement generation. The litho-tephrostratigraphic part of the study was based on the analysis of petrographic, geochemical, and geochronological characteristics of soil horizons and intercalated volcanic ashes with the aim to constrain the timing of individual mass-movement events and their potential correlation. The results were integrated into chronostratigraphic schemes using break-off surfaces, cross-cutting and superposition relationships of landslide deposits and subsequently deposited strata to understand the mass movements in the tectonic and temporal context of the intermontane basin setting, as well as to identify the triggering mechanisms for each event. The MM-5 Guayllabamba mass movement is the result of the collapse of the southwestern slope of the Mojanda volcano and was triggered by the interaction of geologic and morphologic conditions approximately 0,81 Ma. The first debris-avalanche episode of the MM-3 Oyacoto and MM-4 San Francisco mass movements could be related to both geological and morphological conditions, given the highly fractured rocks and uplift of the Bellavista-Catequilla anticline that was subsequently incised at the foot of the slope by fluvial erosion. This first episode of collapse most likely occurred around 0,8 Ma. The MM-2 Bat{\´a}n mass movement was possibly also facilitated by a combination of geological and morphological conditions, most likely associated with a reduction in the lithostatic stresses affecting the Chiche and Mach{\´a}ngara formations and an increase of shear stresses during lateral fluvial scouring processes at the flanks of the source areas. This points to a linked process between river erosion and uplift processes associated with the evolution of the El Bat{\´a}n-La Bota anticline that could have occurred between 0,5 and 0,25 Ma. The voluminous MM-1 Conocoto debris avalanche, as well as the second debris avalanche episode that generated the MM-3 Oyacoto and MM-4 San Francisco mass movements, were caused by the gravitational collapse of the Mojanda and Cangahua formations that are characterized by the intercalation of volcanic ashes. The failure of the eastern flank of the anticlines probably was associated with increased available humidity related to regional Holocene climatic variations. The results of paleosol chronology combined with regional chronostratigraphic and paleoclimate data suggests that these debris avalanches were triggered between 5 and 4 ka. Active tectonics has shaped the morphological features of the Quito-Guayllabamba intermontane basin. The triggering of mass movements in this environment is associated with failure of Pleistocene lithologies (lake sediments, alluvial and volcanic deposits) subjected to ongoing deformation processes, seismic activity, and superposed episodes of climate variability. The Metropolitan District of Quito is an integral part of this complex environment and the geological, climatic, and topographic conditions that continue to influence the urban geographic space within this intermontane basin. The city of Quito comprises the area with the largest urban consolidation including the sub-basins of Quito and San Antonio, with a population of 2,872 million inhabitants, reflecting the importance of studying the inherent geological and climatic hazards that this region is confronted with.},
  language  = {es}
}
@phdthesis{Stallasch2024,
  author    = {Stallasch, Sophie E.},
  title     = {Optimizing power analysis for randomized experiments: Design parameters for student achievement},
  doi       = {10.25932/publishup-62939},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-629396},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 224},
  year      = {2024},
  abstract  = {Randomized trials (RTs) are promising methodological tools to inform evidence-based reform to enhance schooling. Establishing a robust knowledge base on how to promote student achievement requires sensitive RT designs demonstrating sufficient statistical power and precision to draw conclusive and correct inferences on the effectiveness of educational programs and innovations. Proper power analysis is therefore an integral component of any informative RT on student achievement. This venture critically hinges on the availability of reasonable input variance design parameters (and their inherent uncertainties) that optimally reflect the realities around the prospective RT—precisely, its target population and outcome, possibly applied covariates, the concrete design as well as the planned analysis. However, existing compilations in this vein show far-reaching shortcomings. The overarching endeavor of the present doctoral thesis was to substantively expand available resources devoted to tweak the planning of RTs evaluating educational interventions. At the core of this thesis is a systematic analysis of design parameters for student achievement, generating reliable and versatile compendia and developing thorough guidance to support apt power analysis to design strong RTs. To this end, the thesis at hand bundles two complementary studies which capitalize on rich data of several national probability samples from major German longitudinal large-scale assessments. Study I applied two- and three-level latent (covariate) modeling to analyze design parameters for a wide spectrum of mathematical-scientific, verbal, and domain-general achievement outcomes. Three vital covariate sets were covered comprising (a) pretests, (b) sociodemographic characteristics, and (c) their combination. The accumulated estimates were additionally summarized in terms of normative distributions. Study II specified (manifest) single-, two-, and three-level models and referred to influential psychometric heuristics to analyze design parameters and develop concise selection guidelines for covariate (a) types of varying bandwidth-fidelity (domain-identical, cross-domain, fluid intelligence pretests; sociodemographic characteristics), (b) combinations quantifying incremental validities, and (c) time lags of 1- to 7-year-lagged pretests scrutinizing validity degradation. The estimates for various mathematical-scientific and verbal achievement outcomes were meta-analytically integrated and employed in precision simulations. In doing so, Studies I and II addressed essential gaps identified in previous repertoires in six major dimensions: Taken together, this thesis accumulated novel design parameters and deliberate guidance for RT power analysis (1) tailored to four German student (sub)populations across the entire school career from Grade 1 to 12, (2) matched to 21 achievement (sub)domains, (3) adjusted for 11 covariate sets enriched by empirically supported guidelines, (4) adapted to six RT designs, (5) suitable for latent and manifest analysis models, (6) which were cataloged along with quantifications of their associated uncertainties. These resources are complemented by a plethora of illustrative application examples to gently direct psychological and educational researchers through pivotal steps in the process of RT design. The striking heterogeneity of the design parameter estimates across all these dimensions constitutes the overall, joint key result of Studies I and II. Hence, this work convincingly reinforces calls for a close match between design parameters and the specific peculiarities of the target RT's research context. All in all, the present doctoral thesis offers a—so far unique—nuanced and extensive toolkit to optimize power analysis for sound RTs on student achievement in the German (and similar) school context. It is of utmost importance that research does not tire to spawn robust evidence on what actually works to improve schooling. With this in mind, I hope that the emerging compendia and guidance contribute to the quality and rigor of our randomized experiments in psychology and education.},
  language  = {en}
}
@phdthesis{Boila2024,
  author    = {Boila, Chiara},
  title     = {The processing of OVS and passive sentences in German monolingual and German-Italian simultaneous bilingual children},
  doi       = {10.25932/publishup-62972},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-629723},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xv, 223},
  year      = {2024},
  abstract  = {It is a common finding that preschoolers have difficulties in identifying who is doing what to whom in non-canonical sentences, such as (object-verb-subject) OVS and passive sentences in German. This dissertation investigates how German monolingual and German-Italian simultaneous bilingual children process German OVS sentences in Study 1 and German passives in Study 2. Offline data (i.e., accuracy data) and online data (i.e., eye-gaze and pupillometry data) were analyzed to explore whether children can assign thematic roles during sentence comprehension and processing. Executive functions, language-internal and -external factors were investigated as potential predictors for children's sentence comprehension and processing. Throughout the literature, there are contradicting findings on the relation between language and executive functions. While some results show a bilingual cognitive advantage over monolingual speakers, others suggest there is no relationship between bilingualism and executive functions. If bilingual children possess more advanced executive function abilities than monolingual children, then this might also be reflected in a better performance on linguistic tasks. In the current studies monolingual and bilingual children were tested by means of two executive function tasks: the Flanker task and the task-switching paradigm. However, these findings showed no bilingual cognitive advantages and no better performance by bilingual children in the linguistic tasks. The performance was rather comparable between bilingual and monolingual children, or even better for the monolingual group. This may be due to cross-linguistic influences and language experience (i.e., language input and output). Italian was used because it does not syntactically overlap with the structure of German OVS sentences, and it only overlapped with one of the two types of sentence condition used for the passive study - considering the subject-(finite)verb alignment. The findings showed a better performance of bilingual children in the passive sentence structure that syntactically overlapped in the two languages, providing evidence for cross-linguistic influences. Further factors for children's sentence comprehension were considered. The parents' education, the number of older siblings and language experience variables were derived from a language background questionnaire completed by parents. Scores of receptive vocabulary and grammar, visual and short-term memory and reasoning ability were measured by means of standardized tests. It was shown that higher German language experience by bilinguals correlates with better accuracy in German OVS sentences but not in passive sentences. Memory capacity had a positive effect on the comprehension of OVS and passive sentences in the bilingual group. Additionally, a role was played by executive function abilities in the comprehension of OVS sentences and not of passive sentences. It is suggested that executive function abilities might help children in the sentence comprehension task when the linguistic structures are not yet fully mastered. Altogether, these findings show that bilinguals' poorer performance in the comprehension and processing of German OVS is mainly due to reduced language experience in German, and that the different performance of bilingual children with the two types of passives is mainly due to cross-linguistic influences.},
  language  = {en}
}
@phdthesis{Stange2024,
  author    = {Stange, Maike},
  title     = {A study on Coronin-A and Aip1 function in motility of Dictyostelium discoideum and on Aip1 interchangeability between Dictyostelium discoideum and Arabidopsis thaliana},
  doi       = {10.25932/publishup-62856},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-628569},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiv, 168},
  year      = {2024},
  abstract  = {Actin is one of the most highly conserved proteins in eukaryotes and distinct actin-related proteins with filament-forming properties are even found in prokaryotes. Due to these commonalities, actin-modulating proteins of many species share similar structural properties and proposed functions. The polymerization and depolymerization of actin are critical processes for a cell as they can contribute to shape changes to adapt to its environment and to move and distribute nutrients and cellular components within the cell. However, to what extent functions of actin-binding proteins are conserved between distantly related species, has only been addressed in a few cases. In this work, functions of Coronin-A (CorA) and Actin-interacting protein 1 (Aip1), two proteins involved in actin dynamics, were characterized. In addition, the interchangeability and function of Aip1 were investigated in two phylogenetically distant model organisms. The flowering plant Arabidopsis thaliana (encoding two homologs, AIP1-1 and AIP1-2) and in the amoeba Dictyostelium discoideum (encoding one homolog, DdAip1) were chosen because the functions of their actin cytoskeletons may differ in many aspects. Functional analyses between species were conducted for AIP1 homologs as flowering plants do not harbor a CorA gene. In the first part of the study, the effect of four different mutation methods on the function of Coronin-A protein and the resulting phenotype in D. discoideum was revealed in two genetic knockouts, one RNAi knockdown and a sudden loss-of-function mutant created by chemical-induced dislocation (CID). The advantages and disadvantages of the different mutation methods on the motility, appearance and development of the amoebae were investigated, and the results showed that not all observed properties were affected with the same intensity. Remarkably, a new combination of Selection-Linked Integration and CID could be established. In the second and third parts of the thesis, the exchange of Aip1 between plant and amoeba was carried out. For A. thaliana, the two homologs (AIP1-1 and AIP1-2) were analyzed for functionality as well as in D. discoideum. In the Aip1-deficient amoeba, rescue with AIP1-1 was more effective than with AIP1-2. The main results in the plant showed that in the aip1-2 mutant background, reintroduced AIP1-2 displayed the most efficient rescue and A. thaliana AIP1-1 rescued better than DdAip1. The choice of the tagging site was important for the function of Aip1 as steric hindrance is a problem. The DdAip1 was less effective when tagged at the C-terminus, while the plant AIP1s showed mixed results depending on the tag position. In conclusion, the foreign proteins partially rescued phenotypes of mutant plants and mutant amoebae, despite the organisms only being very distantly related in evolutionary terms.},
  language  = {en}
}
@phdthesis{Antonoglou2024,
  author    = {Antonoglou, Nikolaos},
  title     = {GNSS-based remote sensing: Innovative observation of key hydrological parameters in the Central Andes},
  doi       = {10.25932/publishup-62825},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-628256},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xxii, 116},
  year      = {2024},
  abstract  = {The Central Andean region is characterized by diverse climate zones with sharp transitions between them. In this work, the area of interest is the South-Central Andes in northwestern Argentina that borders with Bolivia and Chile. The focus is the observation of soil moisture and water vapour with Global Navigation Satellite System (GNSS) remote-sensing methodologies. Because of the rapid temporal and spatial variations of water vapour and moisture circulations, monitoring this part of the hydrological cycle is crucial for understanding the mechanisms that control the local climate. Moreover, GNSS-based techniques have previously shown high potential and are appropriate for further investigation. This study includes both logistic-organization effort and data analysis. As for the prior, three GNSS ground stations were installed in remote locations in northwestern Argentina to acquire observations, where there was no availability of third-party data. The methodological development for the observation of the climate variables of soil moisture and water vapour is independent and relies on different approaches. The soil-moisture estimation with GNSS reflectometry is an approximation that has demonstrated promising results, but it has yet to be operationally employed. Thus, a more advanced algorithm that exploits more observations from multiple satellite constellations was developed using data from two pilot stations in Germany. Additionally, this algorithm was slightly modified and used in a sea-level measurement campaign. Although the objective of this application is not related to monitoring hydrological parameters, its methodology is based on the same principles and helps to evaluate the core algorithm. On the other hand, water-vapour monitoring with GNSS observations is a well-established technique that is utilized operationally. Hence, the scope of this study is conducting a meteorological analysis by examining the along-the-zenith air-moisture levels and introducing indices related to the azimuthal gradient. The results of the experiments indicate higher-quality soil moisture observations with the new algorithm. Furthermore, the analysis using the stations in northwestern Argentina illustrates the limits of this technology because of varying soil conditions and shows future research directions. The water-vapour analysis points out the strong influence of the topography on atmospheric moisture circulation and rainfall generation. Moreover, the GNSS time series allows for the identification of seasonal signatures, and the azimuthal-gradient indices permit the detection of main circulation pathways.},
  language  = {en}
}
@phdthesis{Drescher2024,
  author    = {Drescher, Cedric},
  title     = {Die Bek{\"a}mpfung transnationaler Kriminalit{\"a}t im Kontext fragiler Staatlichkeit},
  doi       = {10.25932/publishup-62854},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-628542},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIII, 541, LVIII},
  year      = {2024},
  abstract  = {Die Arbeit „Die Bek{\"a}mpfung transnationaler Kriminalit{\"a}t im Kontext fragiler Staatlichkeit" widmet sich dem Ph{\"a}nomen grenz{\"u}berschreitend t{\"a}tiger Akteure der organisierten Kriminalit{\"a}t die den Umstand ausnutzen, dass einige international anerkannte Regierungen nur eine unzureichende Kontrolle {\"u}ber Teile ihres Staatsgebietes aus{\"u}ben. Es wird untersucht, weshalb der durch die internationale Staatengemeinschaft geschaffene Rechtsrahmen, zur Bek{\"a}mpfung transnationaler Kriminalit{\"a}tsph{\"a}nomene im Kontext dieser fragilen Staaten, nicht oder nur defizit{\"a}r dazu beitr{\"a}gt die Kriminalit{\"a}tsph{\"a}nomene zu bek{\"a}mpfen. Nachdem zun{\"a}chst er{\"o}rtert wird, was im Rahmen der Untersuchung unter dem Begriff der transnationalen Kriminalit{\"a}t verstanden wird, wird der internationale Rechtsrahmen zur Bek{\"a}mpfung anhand von f{\"u}nf beispielhaft ausgew{\"a}hlten transnationalen Kriminalit{\"a}tsph{\"a}nomenen beschrieben. Im darauffolgenden Hauptteil der Untersuchung wird der Frage nachgegangen, weshalb dieser durch die internationale Staatengemeinschaft geschaffene Rechtsrahmen, gerade in fragilen Staaten, kaum einen Beitrag dazu leistet solchen Kriminalit{\"a}tsph{\"a}nomenen effektiv zu begegnen. Dabei wird festgestellt, dass die Genese des internationalen Rechtsrahmens zu einem Legitimit{\"a}tsdefizit desselbigen f{\"u}hrt. Auch die mangelhafte Ber{\"u}cksichtigung der speziellen Lebensrealit{\"a}ten, die in vielen fragilen Staaten vorzufinden sind, wirkt sich negativ auf die Durchsetzbarkeit des internationalen Rechtsrahmens aus. Es wird dargelegt, dass unterschiedlich hohe menschenrechtliche Schutzstandards zu Normenkollisionen bei der internationalen Zusammenarbeit der Staaten f{\"u}hren, insbesondere im Rahmen der internationalen Rechtshilfe. Da gerade fragile Staaten h{\"a}ufig durch eine defizit{\"a}re menschenrechtliche Situation gekennzeichnet sind, stellt dies konsolidierte Staaten im Rahmen der Zusammenarbeit mit fragilen Staaten {\"o}fters vor Herausforderungen. Schließlich wird aufgezeigt, dass auch die extraterritoriale Jurisdiktion und somit die strafrechtliche Verfolgung transnationaler Straftaten durch Drittstaaten mit rechtlichen und praktischen Problemen einhergeht. In einem letzten Kapitel der Arbeit wird der Frage nachgegangen, ob nicht ein alternativer Strafverfolgungsmechanismus geschaffen werden sollte, um transnationale Kriminalit{\"a}tsph{\"a}nomene zu verfolgen, die aus fragilen Staaten heraus begangen werden und wie ein solch alternativer Strafverfolgungsmechanismus konkret ausgestaltet sein sollte.},
  language  = {de}
}
@phdthesis{Schallau2024,
  author    = {Schallau, Juliane},
  title     = {"Maybe Happen Is Never Once" - temporalities of guilt in William Faulkner},
  doi       = {10.25932/publishup-62885},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-628858},
  school      = {Universit{\"a}t Potsdam},
  pages     = {iv, 171},
  year      = {2024},
  abstract  = {This study focuses on William Faulkner, whose works explore the demise of the slavery-based Old South during the Civil War in a highly experimental narrative style. Central to this investigation is the analysis of the temporal dimensions of both individual and collective guilt, thus offering a new approach to the often-discussed problem of Faulkner's portrayal of social decay. The thesis examines how Faulkner re-narrates the legacy of the Old South as a guilt narrative and argues that Faulkner uses guilt in order to corroborate his concept of time and the idea of the continuity of the past. The focus of the analysis is on three of Faulkner's arguably most important novels: The Sound and the Fury, Absalom, Absalom!, and Go Down, Moses. Each of these novels features a main character deeply overwhelmed by the crimes of the past, whether private, familial, or societal. As a result, guilt is explored both from a domestic as well as a social perspective. In order to show how Faulkner blends past and present by means of guilt, this work examines several methods and motifs borrowed from different fields and genres with which Faulkner narratively negotiates guilt. These include religious notions of original sin, the motif of the ancestral curse prevalent in the Southern Gothic genre, and the psychological concept of trauma. Each of these motifs emphasizes the temporal dimensions of guilt, which are the core of this study, and makes clear that guilt in Faulkner's work is primarily to be understood as a temporal rather than a moral problem.},
  language  = {en}
}
@phdthesis{Hartmann2024,
  author    = {Hartmann, Anne},
  title     = {Tracing the evolution of hillslope structure and hillslope hydrological response over ten millennia in two glacial forefields of different geology},
  doi       = {10.25932/publishup-62862},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-628629},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XVIII, 138, XLIV},
  year      = {2024},
  abstract  = {Assessing the impact of global change on hydrological systems is one of the greatest hydrological challenges of our time. Changes in land cover, land use, and climate have an impact on water quantity, quality, and temporal availability. There is a widespread consensus that, given the far-reaching effects of global change, hydrological systems can no longer be viewed as static in their structure; instead, they must be regarded as entire ecosystems, wherein hydrological processes interact and coevolve with biological, geomorphological, and pedological processes. To accurately predict the hydrological response under the impact of global change, it is essential to understand this complex coevolution. The knowledge of how hydrological processes, in particular the formation of subsurface (preferential) flow paths, evolve within this coevolution and how they feed back to the other processes is still very limited due to a lack of observational data. At the hillslope scale, this intertwined system of interactions is known as the hillslope feedback cycle. This thesis aims to enhance our understanding of the hillslope feedback cycle by studying the coevolution of hillslope structure and hillslope hydrological response. Using chronosequences of moraines in two glacial forefields developed from siliceous and calcareous glacial till, the four studies shed light on the complex coevolution of hydrological, biological, and structural hillslope properties, as well as subsurface hydrological flow paths over an evolutionary period of 10 millennia in these two contrasting geologies. The findings indicate that the contrasting properties of siliceous and calcareous parent materials lead to variations in soil structure, permeability, and water storage. As a result, different plant species and vegetation types are favored on siliceous versus calcareous parent material, leading to diverse ecosystems with distinct hydrological dynamics. The siliceous parent material was found to show a higher activity level in driving the coevolution. The soil pH resulting from parent material weathering emerges as a crucial factor, influencing vegetation development, soil formation, and consequently, hydrology. The acidic weathering of the siliceous parent material favored the accumulation of organic matter, increasing the soils' water storage capacity and attracting acid-loving shrubs, which further promoted organic matter accumulation and ultimately led to podsolization after 10 000 years. Tracer experiments revealed that the subsurface flow path evolution was influenced by soil and vegetation development, and vice versa. Subsurface flow paths changed from vertical, heterogeneous matrix flow to finger-like flow paths over a few hundred years, evolving into macropore flow, water storage, and lateral subsurface flow after several thousand years. The changes in flow paths among younger age classes were driven by weathering processes altering soil structure, as well as by vegetation development and root activity. In the older age class, the transition to more water storage and lateral flow was attributed to substantial organic matter accumulation and ongoing podsolization. The rapid vertical water transport in the finger-like flow paths, along with the conductive sandy material, contributed to podsolization and thus to the shift in the hillslope hydrological response. In contrast, the calcareous site possesses a high pH buffering capacity, creating a neutral to basic environment with relatively low accumulation of dead organic matter, resulting in a lower water storage capacity and the establishment of predominantly grass vegetation. The coevolution was found to be less dynamic over the millennia. Similar to the siliceous site, significant changes in subsurface flow paths occurred between the young age classes. However, unlike the siliceous site, the subsurface flow paths at the calcareous site only altered in shape and not in direction. Tracer experiments showed that flow paths changed from vertical, heterogeneous matrix flow to vertical, finger-like flow paths after a few hundred to thousands of years, which was driven by root activities and weathering processes. Despite having a finer soil texture, water storage at the calcareous site was significantly lower than at the siliceous site, and water transport remained primarily rapid and vertical, contributing to the flourishing of grass vegetation. The studies elucidated that changes in flow paths are predominantly shaped by the characteristics of the parent material and its weathering products, along with their complex interactions with initial water flow paths and vegetation development. Time, on the other hand, was not found to be a primary factor in describing the evolution of the hydrological response. This thesis makes a valuable contribution to closing the gap in the observations of the coevolution of hydrological processes within the hillslope feedback cycle, which is important to improve predictions of hydrological processes in changing landscapes. Furthermore, it emphasizes the importance of interdisciplinary studies in addressing the hydrological challenges arising from global change.},
  language  = {en}
}
@phdthesis{Wortmann2023,
  author    = {Wortmann, Hanna Rosalie},
  title     = {Food Neophilie},
  doi       = {10.25932/publishup-62857},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-628572},
  school      = {Universit{\"a}t Potsdam},
  pages     = {164},
  year      = {2023},
  abstract  = {Trotz der eindeutigen Vorteile einer ausgewogenen Ern{\"a}hrung halten sich viele Menschen weltweit nicht an entsprechende Ern{\"a}hrungsrichtlinien. Um angemessene Strategien zur Unterst{\"u}tzung einer gesundheitsf{\"o}rdernden Ern{\"a}hrung zu entwickeln, ist ein Verst{\"a}ndnis der zugrunde liegenden Faktoren unerl{\"a}sslich. Insbesondere die Gruppe der {\"a}lteren Erwachsenen stellt dabei eine wichtige Zielgruppe f{\"u}r ern{\"a}hrungsbezogene Pr{\"a}ventions- und Interventionsans{\"a}tze dar. Einer der vielen Faktoren, die als Determinanten einer gesundheitsf{\"o}rdernden Ern{\"a}hrung diskutiert werden, ist die Food Neophilie, also die Bereitschaft, neue und unbekannte Lebensmittel auszuprobieren. Aktuelle Forschungsergebnisse legen nahe, dass die Food Neophilie positiv mit einer gesundheitsf{\"o}rdernden Ern{\"a}hrung in Verbindung steht, allerdings ist die bisherige Forschung in diesem Bereich {\"a}ußerst begrenzt. Das Ziel der Dissertation war es, das Konstrukt der Food Neophilie sowie seine Beziehung zu gesundheitsf{\"o}rderndem Ern{\"a}hrungsverhalten im h{\"o}heren Erwachsenenalter grundlegend zu erforschen, um das Potenzial der Food Neophilie f{\"u}r die Gesundheitsf{\"o}rderung {\"a}lterer Erwachsener besser zu verstehen. Dabei wurde im Rahmen der ersten Publikation zun{\"a}chst untersucht, wie sich das Konstrukt der Food Neophilie reliabel und valide erfassen l{\"a}sst, um weiterf{\"u}hrende Untersuchungen der Food Neophilie zu erm{\"o}glichen. Die psychometrische Validierung der deutschen Version der Variety Seeking Tendency Scale (VARSEEK) basierte auf zwei unabh{\"a}ngigen Stichproben mit insgesamt N = 1000 Teilnehmenden und best{\"a}tigte, dass es sich bei der Skala um ein reliables und valides Messinstrument zur Erfassung der Food Neophilie handelt. Darauf aufbauend wurde im Rahmen der zweiten Publikation die Beziehung der Food Neophilie und der Ern{\"a}hrungsqualit{\"a}t {\"u}ber die Zeit hinweg analysiert. Die prospektive Untersuchung von N = 960 Teilnehmenden des h{\"o}heren Erwachsenenalters (M = 63.4 Jahre) anhand einer Cross-Lagged-Panel-Analyse ergab hohe zeitliche Stabilit{\"a}ten der Food Neophilie und der Ern{\"a}hrungsqualit{\"a}t {\"u}ber einen Zeitraum von drei Jahren. Es zeigte sich zudem ein positiver querschnittlicher Zusammenhang zwischen der Food Neophilie und der Ern{\"a}hrungsqualit{\"a}t, jedoch wurde die Food Neophilie nicht als signifikante Determinante der Ern{\"a}hrungsqualit{\"a}t {\"u}ber die Zeit hinweg identifiziert. In der dritten Publikation wurden schließlich nicht nur die individuellen Auswirkungen der Food Neophilie auf die Ern{\"a}hrungsqualit{\"a}t betrachtet, sondern auch potenzielle dynamische Wechselwirkungen innerhalb von Partnerschaften einbezogen. Hierzu erfolgte mittels eines Actor-Partner-Interdependence-Modells eine Differenzierung potenzieller intra- und interpersoneller Einfl{\"u}sse der Food Neophilie auf die Ern{\"a}hrungsqualit{\"a}t. Im Rahmen der dyadischen Analyse zeigte sich bei N = 390 heterosexuellen Paaren im h{\"o}heren Erwachsenenalter (M = 64.0 Jahre) ein Dominanzmuster: W{\"a}hrend die Food Neophilie der Frauen positiv mit ihrer eigenen Ern{\"a}hrungsqualit{\"a}t und der ihrer Partner zusammenhing, war die Food Neophilie der M{\"a}nner nicht mit der Ern{\"a}hrungsqualit{\"a}t des Paares assoziiert. Insgesamt leistet die vorliegende Dissertation einen wertvollen Beitrag zum umfassenden Verst{\"a}ndnis der Food Neophilie sowie ihrer Rolle im Kontext der Ern{\"a}hrungsgesundheit {\"a}lterer Erwachsener. Trotz fehlender Vorhersagekraft {\"u}ber die Zeit hinweg deutet der positive Zusammenhang zwischen Food Neophilie und Ern{\"a}hrungsqualit{\"a}t darauf hin, dass die Fokussierung auf eine positive und neugierige Einstellung gegen{\"u}ber Lebensmitteln eine innovative Perspektive f{\"u}r Pr{\"a}ventions- und Interventionsans{\"a}tze zur Unterst{\"u}tzung einer gesundheitsf{\"o}rdernden Ern{\"a}hrung {\"a}lterer Erwachsener bieten k{\"o}nnte.},
  language  = {de}
}
@phdthesis{Ketzer2024,
  author    = {Ketzer, Laura},
  title     = {The impact of stellar activity evolution on atmospheric mass loss of young exoplanets},
  doi       = {10.25932/publishup-62681},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-626819},
  school      = {Universit{\"a}t Potsdam},
  pages     = {x, 208},
  year      = {2024},
  abstract  = {The increasing number of known exoplanets raises questions about their demographics and the mechanisms that shape planets into how we observe them today. Young planets in close-in orbits are exposed to harsh environments due to the host star being magnetically highly active, which results in high X-ray and extreme UV fluxes impinging on the planet. Prolonged exposure to this intense photoionizing radiation can cause planetary atmospheres to heat up, expand and escape into space via a hydrodynamic escape process known as photoevaporation. For super-Earth and sub-Neptune-type planets, this can even lead to the complete erosion of their primordial gaseous atmospheres. A factor of interest for this particular mass-loss process is the activity evolution of the host star. Stellar rotation, which drives the dynamo and with it the magnetic activity of a star, changes significantly over the stellar lifetime. This strongly affects the amount of high-energy radiation received by a planet as stars age. At a young age, planets still host warm and extended envelopes, making them particularly susceptible to atmospheric evaporation. Especially in the first gigayear, when X-ray and UV levels can be 100 - 10,000 times higher than for the present-day sun, the characteristics of the host star and the detailed evolution of its high-energy emission are of importance. In this thesis, I study the impact of stellar activity evolution on the high-energy-induced atmospheric mass loss of young exoplanets. The PLATYPOS code was developed as part of this thesis to calculate photoevaporative mass-loss rates over time. The code, which couples parameterized planetary mass-radius relations with an analytical hydrodynamic escape model, was used, together with Chandra and eROSITA X-ray observations, to investigate the future mass loss of the two young multiplanet systems V1298 Tau and K2-198. Further, in a numerical ensemble study, the effect of a realistic spread of activity tracks on the small-planet radius gap was investigated for the first time. The works in this thesis show that for individual systems, in particular if planetary masses are unconstrained, the difference between a young host star following a low-activity track vs. a high-activity one can have major implications: the exact shape of the activity evolution can determine whether a planet can hold on to some of its atmosphere, or completely loses its envelope, leaving only the bare rocky core behind. For an ensemble of simulated planets, an observationally-motivated distribution of activity tracks does not substantially change the final radius distribution at ages of several gigayears. My simulations indicate that the overall shape and slope of the resulting small-planet radius gap is not significantly affected by the spread in stellar activity tracks. However, it can account for a certain scattering or fuzziness observed in and around the radius gap of the observed exoplanet population.},
  language  = {en}
}
@phdthesis{Anda2020,
  author    = {Anda, Carolin},
  title     = {Reisen mit/durch/auf Facebook},
  doi       = {10.25932/publishup-62489},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-624896},
  school      = {Universit{\"a}t Potsdam},
  pages     = {237},
  year      = {2020},
  abstract  = {Die vorliegende Arbeit untersucht Urlaubsfotografien bei Facebook und beschreibt, welche sozio-technischen Medienpraktiken sich innerhalb der Social-Media Plattform {\"u}ber die Fotografien vollziehen. Fotografische Praktiken sind durch aktive Handlungen und soziale Gebrauchsweisen bestimmt. Urlaubsfotografien tragen zum Beispiel zur Strukturierung von Reiserouten und Vorstellungen bei, indem genrespezifische Motive und Rahmungen mit Hilfe von Medien reproduziert und wiederholt werden. Praktiken des Zeigens, Teilens und Kommunizierens werden durch Social Plug-Ins (Like/Share Buttons) und Tagging-Funktionen auch in die Benutzeroberfl{\"a}chen von Facebook integriert. Dadurch werden Nutzer*innen Aktivit{\"a}ten und technische Prozesse miteinander verbunden. Am Beispiel der automatischen Generierung von Urlaubsfotografien auf Geotagseiten wird gezeigt, dass Social-Tagging zur Entstehung und Aushandlung geographischer R{\"a}ume und Ortsvorstellungen beitr{\"a}gt. Mithilfe technischer Strukturierungen von Fotografien auf Taggingseiten werden genrespezifische Motive, fotografische Trends und {\"A}sthetiken besonders sichtbar. Allerdings wird ihre Visualisierung auch durch algorithmische Priorisierung einzelner Inhalte mitbestimmt. Dadurch werden Urlaubsfotografien f{\"u}r ein fotografisches Profiling genutzt, da sie das algorithmische Erfassen und Auswerten von Nutzer*innen-Informationen erm{\"o}glichen. Die Arbeit zeigt, dass der Einsatz von Bilderkennungsverfahren und fotografischen Datenanalysen zu einer optimierten Informationsgewinnung und zu einer Standardisierung von Fotografien beitr{\"a}gt.},
  language  = {de}
}
@phdthesis{Manu2023,
  author    = {Manu, Evans},
  title     = {Hydrogeochemical characterization of water resources in the Pra Basin (Ghana) for quality assessment and water management},
  doi       = {10.25932/publishup-62806},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-628062},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XVI, 106},
  year      = {2023},
  abstract  = {Watershed management requires an understanding of key hydrochemical processes. The Pra Basin is one of the five major river basins in Ghana with a population of over 4.2 million people. Currently, water resources management faces challenges due to surface water pollution caused by the unregulated release of untreated household and industrial waste into aquatic ecosystems and illegal mining activities. This has increased the need for groundwater as the most reliable water supply. Our understanding of groundwater recharge mechanisms and chemical evolution in the basin has been inadequate, making effective management difficult. Therefore, the main objective of this work is to gain insight into the processes that determine the hydrogeochemical evolution of groundwater quality in the Pra Basin. The combined use of stable isotope, hydrochemistry, and water level data provides the basis for conceptualizing the chemical evolution of groundwater in the Pra Basin. For this purpose, the origin and evaporation rates of water infiltrating into the unsaturated zone were evaluated. In addition, Chloride Mass Balance (CMB) and Water Table Fluctuations (WTF) were considered to quantify groundwater recharge for the basin. Indices such as water quality index (WQI), sodium adsorption ratio (SAR), Wilcox diagram, and salinity (USSL) were used in this study to determine the quality of the resource for use as drinking water and for irrigation purposes. Due to the heterogeneity of the hydrochemical data, the statistical techniques of hierarchical cluster and factor analysis were applied to subdivide the data according to their spatial correlation. A conceptual hydrogeochemical model was developed and subsequently validated by applying combinatorial inverse and reaction pathway-based geochemical models to determine plausible mineral assemblages that control the chemical composition of the groundwater. The interactions between water and rock determine the groundwater quality in the Pra Basin. The results underline that the groundwater is of good quality and can be used for drinking water and irrigation purposes. It was demonstrated that there is a large groundwater potential to meet the entire Pra Basin's current and future water demands. The main recharge area was identified as the northern zone, while the southern zone is the discharge area. The predominant influence of weathering of silicate minerals plays a key role in the chemical evolution of the groundwater. The work presented here provides fundamental insights into the hydrochemistry of the Pra Basin and provides data important to water managers for informed decision-making in planning and allocating water resources for various purposes. A novel inverse modelling approach was used in this study to identify different mineral compositions that determine the chemical evolution of groundwater in the Pra Basin. This modelling technique has the potential to simulate the composition of groundwater at the basin scale with large hydrochemical heterogeneity, using average water composition to represent established spatial groupings of water chemistry.},
  language  = {en}
}
@phdthesis{Koehler2024,
  author    = {K{\"o}hler, Wolfgang},
  title     = {Challenges of efficient and compliant data processing},
  doi       = {10.25932/publishup-62784},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-627843},
  school      = {Universit{\"a}t Potsdam},
  pages     = {195},
  year      = {2024},
  abstract  = {Die fortschreitende Digitalisierung ver{\"a}ndert die Gesellschaft und hat weitreichende Auswirkungen auf Menschen und Unternehmen. Grundlegend f{\"u}r diese Ver{\"a}nderungen sind die neuen technologischen M{\"o}glichkeiten, Daten in immer gr{\"o}ßerem Umfang und f{\"u}r vielf{\"a}ltige neue Zwecke zu verarbeiten. Von besonderer Bedeutung ist dabei die Verf{\"u}gbarkeit großer und qualitativ hochwertiger Datens{\"a}tze, insbesondere auf Basis personenbezogener Daten. Sie werden entweder zur Verbesserung der Produktivit{\"a}t, Qualit{\"a}t und Individualit{\"a}t von Produkten und Dienstleistungen oder gar zur Entwicklung neuartiger Dienstleistungen verwendet. Heute wird das Nutzerverhalten, trotz weltweit steigender gesetzlicher Anforderungen an den Schutz personenbezogener Daten, aktiver und umfassender verfolgt als je zuvor. Dies wirft vermehrt ethische, moralische und gesellschaftliche Fragen auf, die nicht zuletzt durch popul{\"a}re F{\"a}lle des Datenmissbrauchs in den Vordergrund der politischen Debatte ger{\"u}ckt sind. Angesichts dieses Diskurses und der gesetzlichen Anforderungen muss heutiges Datenmanagement drei Bedingungen erf{\"u}llen: Erstens die Legalit{\"a}t bzw. Gesetzeskonformit{\"a}t der Nutzung, zweitens die ethische Legitimit{\"a}t. Drittens sollte die Datennutzung aus betriebswirtschaftlicher Sicht wertsch{\"o}pfend sein. Im Rahmen dieser Bedingungen verfolgt die vorliegende kumulative Dissertation vier Forschungsziele mit dem Fokus, ein besseres Verst{\"a}ndnis (1) der Herausforderungen bei der Umsetzung von Gesetzen zum Schutz von Privatsph{\"a}re, (2) der Faktoren, die die Bereitschaft der Kunden zur Weitergabe pers{\"o}nlicher Daten beeinflussen, (3) der Rolle des Datenschutzes f{\"u}r das digitale Unternehmertum und (4) der interdisziplin{\"a}ren wissenschaftlichen Bedeutung, deren Entwicklung und Zusammenh{\"a}nge zu erlangen.},
  language  = {en}
}
@phdthesis{Mueller2024,
  author    = {M{\"u}ller, Daniel},
  title     = {Identification and monitoring of structures, controls, and evolution dynamics of hydrothermal systems and associated alteration through high-resolution remote sensing and in situ analysis},
  doi       = {10.25932/publishup-62668},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-626683},
  school      = {Universit{\"a}t Potsdam},
  pages     = {205},
  year      = {2024},
  abstract  = {Volcanic hydrothermal systems are an integral part of most volcanoes and typically involve a heat source, adequate fluid supply, and fracture or pore systems through which the fluids can circulate within the volcanic edifice. Associated with this are subtle but powerful processes that can significantly influence the evolution of volcanic activity or the stability of the near-surface volcanic system through mechanical weakening, permeability reduction, and sealing of the affected volcanic rock. These processes are well constrained for rock samples by laboratory analyses but are still difficult to extrapolate and evaluate at the scale of an entire volcano. Advances in unmanned aircraft systems (UAS), sensor technology, and photogrammetric processing routines now allow us to image volcanic surfaces at the centimeter scale and thus study volcanic hydrothermal systems in great detail. This thesis aims to explore the potential of UAS approaches for studying the structures, processes, and dynamics of volcanic hydrothermal systems but also to develop methodological approaches to uncover secondary information hidden in the data, capable of indicating spatiotemporal dynamics or potentially critical developments associated with hydrothermal alteration. To accomplish this, the thesis describes the investigation of two near-surface volcanic hydrothermal systems, the El Tatio geyser field in Chile and the fumarole field of La Fossa di Vulcano (Italy), both of which are among the best-studied sites of their kind. Through image analysis, statistical, and spatial analyses we have been able to provide the most detailed structural images of both study sites to date, with new insights into the driving forces of such systems but also revealing new potential controls, which are summarized in conceptual site-specific models. Furthermore, the thesis explores methodological remote sensing approaches to detect, classify and constrain hydrothermal alteration and surface degassing from UAS-derived data, evaluated them by mineralogical and chemical ground-truthing, and compares the alteration pattern with the present-day degassing activity. A significant contribution of the often neglected diffuse degassing activity to the total amount of degassing is revealed and constrains secondary processes and dynamics associated with hydrothermal alteration that lead to potentially critical developments like surface sealing. The results and methods used provide new approaches for alteration research, for the monitoring of degassing and alteration effects, and for thermal monitoring of fumarole fields, with the potential to be incorporated into volcano monitoring routines.},
  language  = {en}
}
@phdthesis{MartinezGuajardo2024,
  author    = {Mart{\´i}nez Guajardo, Alejandro},
  title     = {New zwitterionic polymers for antifouling applications},
  doi       = {10.25932/publishup-62682},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-626820},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIX, 145},
  year      = {2024},
  abstract  = {The remarkable antifouling properties of zwitterionic polymers in controlled environments are often counteracted by their delicate mechanical stability. In order to improve the mechanical stabilities of zwitterionic hydrogels, the effect of increased crosslinker densities was thus explored. In a first approach, terpolymers of zwitterionic monomer 3-[N -2(methacryloyloxy)ethyl-N,N-dimethyl]ammonio propane-1-sulfonate (SPE), hydrophobic monomer butyl methacrylate (BMA), and photo-crosslinker 2-(4-benzoylphenoxy)ethyl methacrylate (BPEMA) were synthesized. Thin hydrogel coatings of the copolymers were then produced and photo-crosslinked. Studies of the swollen hydrogel films showed that not only the mechanical stability but also, unexpectedly, the antifouling properties were improved by the presence of hydrophobic BMA units in the terpolymers. Based on the positive results shown by the amphiphilic terpolymers and in order to further test the impact that hydrophobicity has on both the antifouling properties of zwitterionic hydrogels and on their mechanical stability, a new amphiphilic zwitterionic methacrylic monomer, 3-((2-(methacryloyloxy)hexyl)dimethylammonio)propane-1-sulfonate (M1), was synthesized in good yields in a multistep synthesis. Homopolymers of M1 were obtained by free-radical polymerization. Similarly, terpolymers of M1, zwitterionic monomer SPE, and photo-crosslinker BPEMA were synthesized by free-radical copolymerization and thoroughly characterized, including its solubilities in selected solvents. Also, a new family of vinyl amide zwitterionic monomomers, namely 3-(dimethyl(2-(N -vinylacetamido)ethyl)ammonio)propane-1-sulfonate (M2), 4-(dimethyl(2-(N-vinylacetamido)ethyl)ammonio)butane-1-sulfonate (M3), and 3-(dimethyl(2-(N-vinylacetamido)ethyl)ammonio)propyl sulfate (M4), together with the new photo-crosslinker 4-benzoyl-N-vinylbenzamide (M5) that is well-suited for copolymerization with vinylamides, are introduced within the scope of the present work. The monomers are synthesized with good yields developing a multistep synthesis. Homopolymers of the new vinyl amide zwitterionic monomers are obtained by free-radical polymerization and thoroughly characterized. From the solubility tests, it is remarkable that the homopolymers produced are fully soluble in water, evidence of their high hydrophilicity. Copolymerization of the vinyl amide zwitterionic monomers, M2, M3, and M4 with the vinyl amide photo-crosslinker M5 proved to require very specific polymerization conditions. Nevertheless, copolymers were successfully obtained by free-radical copolymerization under appropriate conditions. Moreover, in an attempt to mitigate the intrinsic hydrophobicity introduced in the copolymers by the photo-crosslinkers, and based on the proven affinity of quaternized diallylamines to copolymerize with vinyl amides, a new quaternized diallylamine sulfobetaine photo-crosslinker 3-(diallyl(2-(4-benzoylphenoxy)ethyl)ammonio)propane-1-sulfonate (M6) is synthesized. However, despite a priori promising copolymerization suitability, copolymerization with the vinyl amide zwitterionic monomers could not be achieved.},
  language  = {en}
}
@phdthesis{Marx2024,
  author    = {Marx, Carolin Valerie},
  title     = {Escalation of commitment in information systems projects: a cognitive-affective perspective},
  doi       = {10.25932/publishup-62696},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-626969},
  school      = {Universit{\"a}t Potsdam},
  pages     = {174},
  year      = {2024},
  abstract  = {While information systems (IS) projects are pivotal in guiding organizational strategies and sustaining competitive advantages, they frequently overrun budgets, extend beyond timelines, and experience high failure rates. This dissertation delves into the psychological micro-foundations of human behavior - specifically cognition and emotion - in relation to a prevalent issue in IS project management: the tendency to persist with failing courses of action, also called escalation of commitment (EoC). Through a mixed-methods research approach, this study investigates the emotional and cognitive bases of decision-making during IS project escalation and its evolution over time. The results of a psychophysiological laboratory experiment provide evidence for the predictions on the role of negative and complex situational integral emotions of Cognitive Dissonance over Coping Theory and add to a better understanding of how escalation tendencies change during sequential decision-making due to cognitive learning effects. Using psychophysiological measures, including data triangulation between electrodermal and cardiovascular activity and AI-based analysis of facial micro-expressions, this research reveals physiological markers of behavioral escalation tendencies. Complementing the experiment, a qualitative analysis using free-form narration during decision-making simulations shows that decision-makers employ varied cognitive reasoning patterns to justify escalating behaviors, suggesting a sequence of four distinct cognitive phases. By integrating both qualitative and quantitative findings, this dissertation offers a comprehensive theoretical framework of how cognition and emotion shape behavioral EoC over time. I propose that escalation is a cyclical adaptation of mental models, distinguished by shifts in cognitive reasoning patterns, temporal cognition mode variations, and interactions with situational emotions and their anticipation. The primary contribution of this dissertation lies in disentangling the emotional and cognitive mechanisms that drive IS project escalation. The findings provide the basis for developing de-escalation strategies, thereby helping to improve decision-making under uncertainty. Stakeholders involved in IS projects that get "off track" should be aware of the tendency to persist with failing courses of action and the importance of the underlying emotional and cognitive dynamics.},
  language  = {de}
}
@phdthesis{AlhosseiniAlmodarresiYasin2024,
  author    = {Alhosseini Almodarresi Yasin, Seyed Ali},
  title     = {Classification, prediction and evaluation of graph neural networks on online social media platforms},
  doi       = {10.25932/publishup-62642},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-626421},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xviii, 78},
  year      = {2024},
  abstract  = {The vast amount of data generated on social media platforms have made them a valuable source of information for businesses, governments and researchers. Social media data can provide insights into user behavior, preferences, and opinions. In this work, we address two important challenges in social media analytics. Predicting user engagement with online content has become a critical task for content creators to increase user engagement and reach larger audiences. Traditional user engagement prediction approaches rely solely on features derived from the user and content. However, a new class of deep learning methods based on graphs captures not only the content features but also the graph structure of social media networks. This thesis proposes a novel Graph Neural Network (GNN) approach to predict user interaction with tweets. The proposed approach combines the features of users, tweets and their engagement graphs. The tweet text features are extracted using pre-trained embeddings from language models, and a GNN layer is used to embed the user in a vector space. The GNN model then combines the features and graph structure to predict user engagement. The proposed approach achieves an accuracy value of 94.22\% in classifying user interactions, including likes, retweets, replies, and quotes. Another major challenge in social media analysis is detecting and classifying social bot accounts. Social bots are automated accounts used to manipulate public opinion by spreading misinformation or generating fake interactions. Detecting social bots is critical to prevent their negative impact on public opinion and trust in social media. In this thesis, we classify social bots on Twitter by applying Graph Neural Networks. The proposed approach uses a combination of both the features of a node and an aggregation of the features of a node's neighborhood to classify social bot accounts. Our final results indicate a 6\% improvement in the area under the curve score in the final predictions through the utilization of GNN. Overall, our work highlights the importance of social media data and the potential of new methods such as GNNs to predict user engagement and detect social bots. These methods have important implications for improving the quality and reliability of information on social media platforms and mitigating the negative impact of social bots on public opinion and discourse.},
  language  = {en}
}