@phdthesis{Adelt2024,
  author    = {Adelt, Anne},
  title     = {The Relativized Minimality approach to comprehension of German relative clauses in aphasia},
  doi       = {10.25932/publishup-62331},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-623312},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiii, 166},
  year      = {2024},
  abstract  = {It is a well-attested finding in head-initial languages that individuals with aphasia (IWA) have greater difficulties in comprehending object-extracted relative clauses (ORCs) as compared to subject-extracted relative clauses (SRCs). Adopting the linguistically based approach of Relativized Minimality (RM; Rizzi, 1990, 2004), the subject-object asymmetry is attributed to the occurrence of a Minimality effect in ORCs due to reduced processing capacities in IWA (Garraffa \& Grillo, 2008; Grillo, 2008, 2009). For ORCs, it is claimed that the embedded subject intervenes in the syntactic dependency between the moved object and its trace, resulting in greater processing demands. In contrast, no such intervener is present in SRCs. Based on the theoretical framework of RM and findings from language acquisition (Belletti et al., 2012; Friedmann et al., 2009), it is assumed that Minimality effects are alleviated when the moved object and the intervening subject differ in terms of relevant syntactic features. For German, the language under investigation, the RM approach predicts that number (i.e., singular vs. plural) and the lexical restriction [+NP] feature (i.e., lexically restricted determiner phrases vs. lexically unrestricted pronouns) are considered relevant in the computation of Minimality. Greater degrees of featural distinctiveness are predicted to result in more facilitated processing of ORCs, because IWA can more easily distinguish between the moved object and the intervener. This cumulative dissertation aims to provide empirical evidence on the validity of the RM approach in accounting for comprehension patterns during relative clause (RC) processing in German-speaking IWA. For that purpose, I conducted two studies including visual-world eye-tracking experiments embedded within an auditory referent-identification task to study the offline and online processing of German RCs. More specifically, target sentences were created to evaluate (a) whether IWA demonstrate a subject-object asymmetry, (b) whether dissimilarity in the number and/or the [+NP] features facilitates ORC processing, and (c) whether sentence processing in IWA benefits from greater degrees of featural distinctiveness. Furthermore, by comparing RCs disambiguated through case marking (at the relative pronoun or the following noun phrase) and number marking (inflection of the sentence-final verb), it was possible to consider the role of the relative position of the disambiguation point. The RM approach predicts that dissimilarity in case should not affect the occurrence of Minimality effects. However, the case cue to sentence interpretation appears earlier within RCs than the number cue, which may result in lower processing costs in case-disambiguated RCs compared to number-disambiguated RCs. In study I, target sentences varied with respect to word order (SRC vs. ORC) and dissimilarity in the [+NP] feature (lexically restricted determiner phrase vs. pronouns as embedded element). Moreover, by comparing the impact of these manipulations in case- and number-disambiguated RCs, the effect of dissimilarity in the number feature was explored. IWA demonstrated a subject-object asymmetry, indicating the occurrence of a Minimality effect in ORCs. However, dissimilarity neither in the number feature nor in the [+NP] feature alone facilitated ORC processing. Instead, only ORCs involving distinct specifications of both the number and the [+NP] features were well comprehended by IWA. In study II, only temporarily ambiguous ORCs disambiguated through case or number marking were investigated, while controlling for varying points of disambiguation. There was a slight processing advantage of case marking as cue to sentence interpretation as compared to number marking. Taken together, these findings suggest that the RM approach can only partially capture empirical data from German IWA. In processing complex syntactic structures, IWA are susceptible to the occurrence of the intervening subject in ORCs. The new findings reported in the thesis show that structural dissimilarity can modulate sentence comprehension in aphasia. Interestingly, IWA can override Minimality effects in ORCs and derive correct sentence meaning if the featural specifications of the constituents are maximally different, because they can more easily distinguish the moved object and the intervening subject given their reduced processing capacities. This dissertation presents new scientific knowledge that highlights how the syntactic theory of RM helps to uncover selective effects of morpho-syntactic features on sentence comprehension in aphasia, emphasizing the close link between assumptions from theoretical syntax and empirical research.},
  language  = {en}
}
@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{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}
}
@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{Apodiakou2024,
  author    = {Apodiakou, Anastasia},
  title     = {Analysis of the regulation of SDI genes, unravelling the role of the SLIM1 transcription factor, and the SNRK3.15 kinase in Arabidopsis under sulfur deprivation},
  school      = {Universit{\"a}t Potsdam},
  pages     = {141},
  year      = {2024},
  language  = {en}
}
@phdthesis{Aue2024,
  author    = {Aue, Lars},
  title     = {Cyclone impacts on sea ice in the Atlantic Arctic Ocean},
  doi       = {10.25932/publishup-63445},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-634458},
  school      = {Universit{\"a}t Potsdam},
  pages     = {VIII, 131},
  year      = {2024},
  abstract  = {The Arctic is the hot spot of the ongoing, global climate change. Over the last decades, near-surface temperatures in the Arctic have been rising almost four times faster than on global average. This amplified warming of the Arctic and the associated rapid changes of its environment are largely influenced by interactions between individual components of the Arctic climate system. On daily to weekly time scales, storms can have major impacts on the Arctic sea-ice cover and are thus an important part of these interactions within the Arctic climate. The sea-ice impacts of storms are related to high wind speeds, which enhance the drift and deformation of sea ice, as well as to changes in the surface energy budget in association with air mass advection, which impact the seasonal sea-ice growth and melt. The occurrence of storms in the Arctic is typically associated with the passage of transient cyclones. Even though the above described mechanisms how storms/cyclones impact the Arctic sea ice are in principal known, there is a lack of statistical quantification of these effects. In accordance with that, the overarching objective of this thesis is to statistically quantify cyclone impacts on sea-ice concentration (SIC) in the Atlantic Arctic Ocean over the last four decades. In order to further advance the understanding of the related mechanisms, an additional objective is to separate dynamic and thermodynamic cyclone impacts on sea ice and assess their relative importance. Finally, this thesis aims to quantify recent changes in cyclone impacts on SIC. These research objectives are tackled utilizing various data sets, including atmospheric and oceanic reanalysis data as well as a coupled model simulation and a cyclone tracking algorithm. Results from this thesis demonstrate that cyclones are significantly impacting SIC in the Atlantic Arctic Ocean from autumn to spring, while there are mostly no significant impacts in summer. The strength and the sign (SIC decreasing or SIC increasing) of the cyclone impacts strongly depends on the considered daily time scale and the region of the Atlantic Arctic Ocean. Specifically, an initial decrease in SIC (day -3 to day 0 relative to the cyclone) is found in the Greenland, Barents and Kara Seas, while SIC increases following cyclones (day 0 to day 5 relative to the cyclone) are mostly limited to the Barents and Kara Seas. For the cold season, this results in a pronounced regional difference between overall (day -3 to day 5 relative to the cyclone) SIC-decreasing cyclone impacts in the Greenland Sea and overall SIC-increasing cyclone impacts in the Barents and Kara Seas. A cyclone case study based on a coupled model simulation indicates that both dynamic and thermodynamic mechanisms contribute to cyclone impacts on sea ice in winter. A typical pattern consisting of an initial dominance of dynamic sea-ice changes followed by enhanced thermodynamic ice growth after the cyclone passage was found. This enhanced ice growth after the cyclone passage most likely also explains the (statistical) overall SIC-increasing effects of cyclones in the Barents and Kara Seas in the cold season. Significant changes in cyclone impacts on SIC over the last four decades have emerged throughout the year. These recent changes are strongly varying from region to region and month to month. The strongest trends in cyclone impacts on SIC are found in autumn in the Barents and Kara Seas. Here, the magnitude of destructive cyclone impacts on SIC has approximately doubled over the last four decades. The SIC-increasing effects following the cyclone passage have particularly weakened in the Barents Sea in autumn. As a consequence, previously existing overall SIC-increasing cyclone impacts in this region in autumn have recently disappeared. Generally, results from this thesis show that changes in the state of the sea-ice cover (decrease in mean sea-ice concentration and thickness) and near-surface air temperature are most important for changed cyclone impacts on SIC, while changes in cyclone properties (i.e. intensity) do not play a significant role.},
  language  = {en}
}
@phdthesis{Benson2024,
  author    = {Benson, Lawrence},
  title     = {Efficient state management with persistent memory},
  doi       = {10.25932/publishup-62563},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-625637},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xiii, 124},
  year      = {2024},
  abstract  = {Efficiently managing large state is a key challenge for data management systems. Traditionally, state is split into fast but volatile state in memory for processing and persistent but slow state on secondary storage for durability. Persistent memory (PMem), as a new technology in the storage hierarchy, blurs the lines between these states by offering both byte-addressability and low latency like DRAM as well persistence like secondary storage. These characteristics have the potential to cause a major performance shift in database systems. Driven by the potential impact that PMem has on data management systems, in this thesis we explore their use of PMem. We first evaluate the performance of real PMem hardware in the form of Intel Optane in a wide range of setups. To this end, we propose PerMA-Bench, a configurable benchmark framework that allows users to evaluate the performance of customizable database-related PMem access. Based on experimental results obtained with PerMA-Bench, we discuss findings and identify general and implementation-specific aspects that influence PMem performance and should be considered in future work to improve PMem-aware designs. We then propose Viper, a hybrid PMem-DRAM key-value store. Based on PMem-aware access patterns, we show how to leverage PMem and DRAM efficiently to design a key database component. Our evaluation shows that Viper outperforms existing key-value stores by 4-18x for inserts while offering full data persistence and achieving similar or better lookup performance. Next, we show which changes must be made to integrate PMem components into larger systems. By the example of stream processing engines, we highlight limitations of current designs and propose a prototype engine that overcomes these limitations. This allows our prototype to fully leverage PMem's performance for its internal state management. Finally, in light of Optane's discontinuation, we discuss how insights from PMem research can be transferred to future multi-tier memory setups by the example of Compute Express Link (CXL). Overall, we show that PMem offers high performance for state management, bridging the gap between fast but volatile DRAM and persistent but slow secondary storage. Although Optane was discontinued, new memory technologies are continuously emerging in various forms and we outline how novel designs for them can build on insights from existing PMem research.},
  language  = {en}
}
@phdthesis{Benz2024,
  author    = {Benz, Eleanor},
  title     = {The advisory function of the Inter-American Court of Human Rights},
  series = {Beitr{\"a}ge zum ausl{\"a}ndischen {\"o}ffentlichen Recht und V{\"o}lkerrecht},
  volume    = {329},
  journal   = {Beitr{\"a}ge zum ausl{\"a}ndischen {\"o}ffentlichen Recht und V{\"o}lkerrecht},
  publisher = {Nomos},
  address   = {Baden-Baden},
  issn      = {978-3-7489-1980-3},
  doi       = {10.5771/9783748919803},
  school      = {Universit{\"a}t Potsdam},
  pages     = {478},
  year      = {2024},
  abstract  = {How do the rights of same-sex couples have to be ensured by states, and which kind of environmental obligations are induced by the right to life and to personal integrity? Questions as diverse and far-reaching as these are regularly dealt with by the Inter-American Court of Human Rights in its advisory function. This book is the first comprehensive, non-Spanish-written treatise on the advisory function of this Court. It analyzes the scope of the Court's advisory jurisdiction and its procedural practice in comparison with that of other international courts. Moreover, the legal effects of the Court's advisory opinions and the question when the Court should better reject a request for an advisory opinion are examined.},
  language  = {en}
}
@phdthesis{Blanz2024,
  author    = {Blanz, Alkis},
  title     = {Essays on the macroeconomics of climate change and policy},
  pages     = {166},
  year      = {2024},
  language  = {en}
}
@phdthesis{Blaser2024,
  author    = {Blaser, Berenike Lisa},
  title     = {Premenstrual symptoms as a function of altered central autonomous nervous activity},
  doi       = {10.25932/publishup-64597},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-645970},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XII, 265},
  year      = {2024},
  abstract  = {The experience of premenstrual syndrome (PMS) affects up to 90\% of individuals with an active menstrual cycle and involves a spectrum of aversive physiological and psychological symptoms in the days leading up to menstruation (Tschudin et al., 2010). Despite its high prevalence, the precise origins of PMS remain elusive, with influences ranging from hormonal fluctuations to cognitive, social, and cultural factors (Hunter, 2007; Matsumoto et al., 2013). Biologically, hormonal fluctuations, particularly in gonadal steroids, are commonly believed to be implicated in PMS, with the central factor being varying susceptibilities to the fluctuations between individuals and cycles (Rapkin \& Akopians, 2012). Allopregnanolone (ALLO), a neuroactive steroid and progesterone metabolite, has emerged as a potential link to PMS symptoms (Hantsoo \& Epperson, 2020). ALLO is a positive allosteric modulator of the GABAA receptor, influencing inhibitory communication (Rupprecht, 2003; Andr{\´e}en et al., 2006). Different susceptibility to ALLO fluctuations throughout the cycle may lead to reduced GABAergic signal transmission during the luteal phase of the menstrual cycle. The GABAergic system's broad influence leads to a number of affected physiological systems, including a consistent reduction in vagally mediated heart rate variability (vmHRV) during the luteal phase (Schmalenberger et al., 2019). This reduction in vmHRV is more pronounced in individuals with high PMS symptoms (Baker et al., 2008; Matsumoto et al., 2007). Fear conditioning studies have shown inconsistent associations with cycle phases, suggesting a complex interplay between physiological parameters and PMS-related symptoms (Carpenter et al., 2022; Epperson et al., 2007; Milad et al., 2006). The neurovisceral integration model posits that vmHRV reflects the capacity of the central autonomous network (CAN), which is responsible for regulatory processes on behavioral, cognitive, and autonomous levels (Thayer \& Lane, 2000, 2009). Fear learning, mediated within the CAN, is suggested to be indicative of vmHRV's capacity for successful VI regulation (Battaglia \& Thayer, 2022). Given the GABAergic mediation of central inhibitory functional connectivity in the CAN, which may be affected by ALLO fluctuations, this thesis proposes that fluctuating CAN activity in the luteal phase contributes to diverse aversive symptoms in PMS. A research program was designed to empirically test these propositions. Study 1 investigated fear discrimination during different menstrual cycle phases and its interaction with vmHRV, revealing nuanced effects on acoustic startle response and skin conductance response. While there was heightened fear discrimination in acoustic startle responses in participants in the luteal phase, there was an interaction between menstrual cycle phase and vmHRV in skin conductance responses. In this measure, heightened fear discrimination during the luteal phase was only visible in individuals with high resting vmHRV; those with low vmHRV showed reduced fear discrimination and higher overall responses. Despite affecting the vast majority of menstruating people, there are very limited tools available to reliably assess these symptoms in the German speaking area. Study 2 aimed at closing this gap, by translating and validating a German version of the short version of the Premenstrual Assessment Form (Allen et al., 1991), providing a reliable tool for future investigations, which closes the gap in PMS questionnaires in the German-speaking research area. Study 3 employed a diary study paradigm to explore daily associations between vmHRV and PMS symptoms. The results showed clear simultaneous fluctuations between the two constructs with a peak in PMS and a low point in vmHRV a few days before menstruation onset. The association between vmHRV and PMS was driven by psychological PMS symptoms. Based on the theoretical considerations regarding the neurovisceral perspective on PMS, another interesting construct to consider is attentional control, as it is closely related to functions of the CAN. Study 4 delved into attentional control and vmHRV differences between menstrual cycle phases, demonstrating an interaction between cycle phase and PMS symptoms. In a pilot, we found reduced vmHRV and attentional control during the luteal phase only in participants who reported strong PMS. While Studies 1-4 provided evidence for the mechanisms underlying PMS, Studies 5 and 6 investigated short- and long-term intervention protocols to ameliorate PMS symptomatology. Study 5 explored the potential of heart rate variability biofeedback (HRVB) in alleviating PMS symptoms and a number of other outcome measures. In a waitlist-control design, participants underwent a 4-week smartphone-based HRVB intervention. The results revealed positive effects on PMS, with larger effect sizes on psychological symptoms, as well as on depressive symptoms, anxiety/stress and attentional control. Finally, Study 6 examined the acute effects of HRVB on attentional control. The study found positive impact but only in highly stressed individuals. The thesis, based on this comprehensive research program, expands our understanding of PMS as an outcome of CAN fluctuations mediated by GABAA receptor reactivity. The results largely support the model. These findings not only deepen our understanding of PMS but also offer potential avenues for therapeutic interventions. The promising results of smartphone-based HRVB training suggest a non-pharmacological approach to managing PMS symptoms, although further research is needed to confirm its efficacy. In conclusion, this thesis illuminates the complex web of factors contributing to PMS, providing valuable insights into its etiological underpinnings and potential interventions. By elucidating the relationships between hormonal fluctuations, CAN activity, and psychological responses, this research contributes to more effective treatments for individuals grappling with the challenges of PMS. The findings hold promise for improving the quality of life for those affected by this prevalent and often debilitating condition.},
  language  = {en}
}