@phdthesis{Liu2024,
  author    = {Liu, Qingting},
  title     = {Regulation of Starch Granule Morphogenesis in Arabidopsis thaliana},
  school      = {Universit{\"a}t Potsdam},
  pages     = {124},
  year      = {2024},
  abstract  = {Carbohydrates play a vital role in all living organisms; serving as a cornerstone in primary metabolism through the release of energy from their hydrolysis and subsequent re-utilization (Apriyanto et al., 2022). Starch is the principal carbohydrate reserve in plants, providing essential energy for plant growth. Furthermore, starch serves as a significant carbohydrate source in the human diet. Beyond its nutritional value, starch has extensive industrial application associated with many aspects of human society, such as feed, pharmacy, textiles, and the production of biodegradable plastics. Understanding the mechanisms underlying starch metabolism in plants carries multifaceted benefits. Not only does it contribute to increasing crop yield and refining grain quality, but also can improve the efficiency of industrial applications. Starch in plants is categorized into two classes based on their location and function: transitory starch and storage starch. Transitory starch is produced in chloroplasts of autotrophic tissues/organs, such as leaves. It is synthesized during the day and degraded during the night. Storage starch is synthesized in heterotrophic tissues/organs, such as endosperm, roots and tubers, which is utilized for plant reproduction and industrial application in human life. Most studies aiming to comprehend starch metabolism of Arabidopsis thaliana primarily focus on transitory starch. Starch is stored as granular form in chloroplast and amyloplast. The parameters of starch granules, including size, morphology, and quantity per chloroplast serve as indicators of starch metabolism status. However, the understanding of their regulatory mechanism is still incomplete. In this research, I initially employed a simple and adapted method based on laser confocal scanning microscopy (LCSM) to observe size, morphology and quantity of starch granules within chloroplasts in Arabidopsis thaliana in vivo. This method facilitated a rapid and versatile analysis of starch granule parameters across numerous samples. Utilizing this approach, I compared starch granule number per chloroplast between mesophyll cells and guard cells in both wild type plants (Col-0) and several starch related mutants. The results revealed that the granule number is distinct between mesophyll cells and guard cells, even within the same genetic background, suggesting that guard cells operate a unique regulatory mechanism of starch granule number. Subsequently, I redirected my attention toward examining starch morphology. Through microscopy analyses, I observed a gradual alteration in starch granule morphology in certain mutants during leaf aging. Specifically, in mutants such as sex1-8 and dpe2phs1ss4, there was a progressive alteration in starch granule morphology over time. Conversely, in Col-0 and ss4 mutant, these morphological alterations were not evident. This discovery suggests a new perspective to understand the development of starch morphology. Further investigation revealed that mutants lacking either Disproportionating enzyme 2 (DPE2) or MALTOSE-EXCESS 1 (MEX1) exhibited gradual alterations in starch morphology with leaf aging. Notably, the most severe effects on starch morphology occurred in double mutants lacking either DPE2 or MEX1 in conjunction with a lack of starch synthase 4 (SS4). In these mutations, a transformation of the starch granule morphology from the typical discoid morphology to oval and eventually to a spherical shape. To investigate the changes in the internal structure of starch during this alteration, I analyzed the chain length distribution (CLD) of the amylopectin of young, intermediate and old leaves of the mutants. Throughout starch granule development, I found an increased presence of short glucan chains within the granules, particularly evident in dpe2ss4 and mex1ss4 mutants, as well as their parental single mutants. Notably, the single mutant ss4 also showed an affected granule morphology, albeit not influenced by leaf aging.. The CLD pattern of the amylopectin reflects an integrative regulation involving several participants in starch synthesis, including starch synthases (SSs), starch branching/debranching enzymes (SBEs/DBEs). Therefore, I further detected the expression of related genes on transcription level and the enzymatic activity of their respective proteins. Results indicated altered gene expression of several regulators in these mutants, particularly demonstrating dramatic alterations in dpe2 and dpe2ss4 with leaf aging. These changes corresponded with the observed alterations in starch granule morphology. Taken together, I have identified and characterized a progressive alteration in starch granule morphology primarily resulting from the deficiencies in DPE2 and MEX1. Furthermore, I have associated the CLD pattern with the granule morphogenesis, as well as the gene expression and enzymatic activity of proteins involved in starch synthesis. Unlike SS4, which is implicated in starch initiation, MEX1 and DPE2 are involved into starch degradation. MEX1 is located in chloroplast envelope and DPE2 is situated in the cytosol. Considering the locations and known functions of DPE2/MEX1 and SS4, I infer that there might be two pathways influencing starch morphology: an initiation-affected pathway via SS4 and a degradation-affected pathway via DPE2/MEX1.},
  language  = {en}
}
@phdthesis{Pauli2024,
  author    = {Pauli, Daniel},
  title     = {Unraveling massive star and binary physics in the nearby low-metallicity galaxy, the Small Magellanic Cloud, as a proxy for high-redshift galaxies},
  doi       = {10.25932/publishup-65318},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-653184},
  school      = {Universit{\"a}t Potsdam},
  pages     = {169},
  year      = {2024},
  abstract  = {Massive stars (Mini > 8 Msol) are the key feedback agents within galaxies, as they shape their surroundings via their powerful winds, ionizing radiation, and explosive supernovae. Most massive stars are born in binary systems, where interactions with their companions significantly alter their evolution and the feedback they deposit in their host galaxy. Understanding binary evolution, particularly in the low-metallicity environments as proxies for the Early Universe, is crucial for interpreting the rest-frame ultraviolet spectra observed in high-redshift galaxies by telescopes like Hubble and James Webb. This thesis aims to tackle this challenge by investigating in detail massive binaries within the low-metallicity environment of the Small Magellanic Cloud galaxy. From ultraviolet and multi-epoch optical spectroscopic data, we uncovered post-interaction binaries. To comprehensively characterize these binary systems, their stellar winds, and orbital parameters, we use a multifaceted approach. The Potsdam Wolf-Rayet stellar atmosphere code is employed to obtain the stellar and wind parameters of the stars. Additionally, we perform consistent light and radial velocity fitting with the Physics of Eclipsing Binaries software, allowing for the independent determination of orbital parameters and component masses. Finally, we utilize these results to challenge the standard picture of stellar evolution and improve our understanding of low-metallicity stellar populations by calculating our binary evolution models with the Modules for Experiments in Stellar Astrophysics code. We discovered the first four O-type post-interaction binaries in the SMC (Chapters 2, 5, and 6). Their primary stars have temperatures similar to other OB stars and reside far from the helium zero-age main sequence, challenging the traditional view of binary evolution. Our stellar evolution models suggest this may be due to enhanced mixing after core-hydrogen burning. Furthermore, we discovered the so-far most massive binary system undergoing mass transfer (Chapter 3), offering a unique opportunity to test mass-transfer efficiency in extreme conditions. Our binary evolution calculations revealed unexpected evolutionary pathways for accreting stars in binaries, potentially providing the missing link to understanding the observed Wolf-Rayet population within the SMC (Chapter 4). The results presented in this thesis unveiled the properties of massive binaries at low-metallicity which challenge the way the spectra of high-redshift galaxies are currently being analyzed as well as our understanding of massive-star feedback within galaxies.},
  language  = {en}
}
@phdthesis{Fulat2024,
  author    = {Fulat, Karol},
  title     = {Electron acceleration at quasi-perpendicular shocks in supernova remnants},
  doi       = {10.25932/publishup-65136},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-651365},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vi, 94},
  year      = {2024},
  abstract  = {Astrophysical shocks, driven by explosive events such as supernovae, efficiently accelerate charged particles to relativistic energies. The majority of these shocks occur in collisionless plasmas where the energy transfer is dominated by particle-wave interactions.Strong nonrelativistic shocks found in supernova remnants are plausible sites of galactic cosmic ray production, and the observed emission indicates the presence of nonthermal electrons. To participate in the primary mechanism of energy gain - Diffusive Shock Acceleration - electrons must have a highly suprathermal energy, implying a need for very efficient pre-acceleration. This poorly understood aspect of the shock acceleration theory is known as the electron injection problem. Studying electron-scale phenomena requires the use of fully kinetic particle-in-cell (PIC) simulations, which describe collisionless plasma from first principles. Most published studies consider a homogenous upstream medium, but turbulence is ubiquitous in astrophysical environments and is typically driven at magnetohydrodynamic scales, cascading down to kinetic scales. For the first time, I investigate how preexisting turbulence affects electron acceleration at nonrelativistic shocks using the fully kinetic approach. To accomplish this, I developed a novel simulation framework that allows the study of shocks propagating in turbulent media. It involves simulating slabs of turbulent plasma separately, which are further continuously inserted into a shock simulation. This demands matching of the plasma slabs at the interface. A new procedure of matching electromagnetic fields and currents prevents numerical transients, and the plasma evolves self-consistently. The versatility of this framework has the potential to render simulations more consistent with turbulent systems in various astrophysical environments. In this Thesis, I present the results of 2D3V PIC simulations of high-Mach-number nonrelativistic shocks with preexisting compressive turbulence in an electron-ion plasma. The chosen amplitudes of the density fluctuations (\$\lesssim15\\%\$) concord with \textit{in situ} measurements in the heliosphere and the local interstellar medium. I explored how these fluctuations impact the dynamics of upstream electrons, the driving of the plasma instabilities, electron heating and acceleration. My results indicate that while the presence of the turbulence enhances variations in the upstream magnetic field, their levels remain too low to influence the behavior of electrons at perpendicular shocks significantly. However, the situation is different at oblique shocks. The external magnetic field inclined at an angle between \$50^\circ \lesssim \theta_\text{Bn} \lesssim 75^\circ\$ relative to the shock normal allows the escape of fast electrons toward the upstream region. An extended electron foreshock region is formed, where these particles drive various instabilities. Results of an oblique shock with \$\theta_\text{Bn}=60^\circ\$ propagating in preexisting compressive turbulence show that the foreshock becomes significantly shorter, and the shock-reflected electrons have higher temperatures. Furthermore, the energy spectrum of downstream electrons shows a well-pronounced nonthermal tail that follows a power law with an index up to -2.3. The methods and results presented in this Thesis could serve as a starting point for more realistic modeling of interactions between shocks and turbulence in plasmas from first principles.},
  language  = {en}
}
@phdthesis{ValenciaSanmiguel2003,
  author    = {Valencia Sanmiguel, Antonio},
  title     = {Condensation and crystallization on patterned surfaces},
  doi       = {10.25932/publishup-65195},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-651950},
  school      = {Universit{\"a}t Potsdam},
  pages     = {102, XXII},
  year      = {2003},
  abstract  = {Condensation and crystallization are omnipresent phenomena in nature. The formation of droplets or crystals on a solid surface are familiar processes which, beyond their scientific interest, are required in many technological applications. In recent years, experimental techniques have been developed which allow patterning a substrate with surface domains of molecular thickness, surface area in the mesoscopic scale, and different wettabilities (i.e., different degrees of preference for a substance that is in contact with the substrate). The existence of new patterned surfaces has led to increased theoretical efforts to understand wetting phenomena in such systems. In this thesis, we deal with some problems related to the equilibrium of phases (e.g., liquid-vapor coexistence) and the kinetics of phase separation in the presence of chemically patterned surfaces. Two different cases are considered: (i) patterned surfaces in contact with liquid and vapor, and (ii) patterned surfaces in contact with a crystalline phase. One of the problems that we have studied is the following: It is widely believed that if air containing water vapor is cooled to its dew point, droplets of water are immediately formed. Although common experience seems to support this view, it is not correct. It is only when air is cooled well below its dew point that the phase transition occurs immediately. A vapor cooled slightly below its dew point is in a metastable state, meaning that the liquid phase is more stable than the vapor, but the formation of droplets requires some time to occur, which can be very long. It was first pointed out by J. W. Gibbs that the metastability of a vapor depends on the energy necessary to form a nucleus (a droplet of a critical size). Droplets smaller than the critical size will tend to disappear, while droplets larger than the critical size will tend to grow. This is consistent with an energy barrier that has its maximum at the critical size, as is the case for droplets formed directly in the vapor or in contact with a chemically uniform planar wall. Classical nucleation theory describes the time evolution of the condensation in terms of the random process of droplet growth through this energy barrier. This process is activated by thermal fluctuations, which eventually will form a droplet of the critical size. We consider nucleation of droplets from a vapor on a substrate patterned with easily wettable (lyophilic) circular domains. Under certain conditions of pressure and temperature, the condensation of a droplet on a lyophilic circular domain proceeds through a barrier with two maxima (a double barrier). We have extended classical nucleation theory to account for the kinetics of nucleation through a double barrier, and applied this extension to nucleation on lyophilic circular domains.},
  language  = {en}
}
@phdthesis{Arend2024,
  author    = {Arend, Marius},
  title     = {Comparing genome-scale models of protein-constrained metabolism in heterotrophic and photosynthetic microorganisms},
  doi       = {10.25932/publishup-65147},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-651470},
  school      = {Universit{\"a}t Potsdam},
  pages     = {150},
  year      = {2024},
  abstract  = {Genome-scale metabolic models are mathematical representations of all known reactions occurring in a cell. Combined with constraints based on physiological measurements, these models have been used to accurately predict metabolic fluxes and effects of perturbations (e.g. knock-outs) and to inform metabolic engineering strategies. Recently, protein-constrained models have been shown to increase predictive potential (especially in overflow metabolism), while alleviating the need for measurement of nutrient uptake rates. The resulting modelling frameworks quantify the upkeep cost of a certain metabolic flux as the minimum amount of enzyme required for catalysis. These improvements are based on the use of in vitro turnover numbers or in vivo apparent catalytic rates of enzymes for model parameterization. In this thesis several tools for the estimation and refinement of these parameters based on in vivo proteomics data of Escherichia coli, Saccharomyces cerevisiae, and Chlamydomonas reinhardtii have been developed and applied. The difference between in vitro and in vivo catalytic rate measures for the three microorganisms was systematically analyzed. The results for the facultatively heterotrophic microalga C. reinhardtii considerably expanded the apparent catalytic rate estimates for photosynthetic organisms. Our general finding pointed at a global reduction of enzyme efficiency in heterotrophy compared to other growth scenarios. Independent of the modelled organism, in vivo estimates were shown to improve accuracy of predictions of protein abundances compared to in vitro values for turnover numbers. To further improve the protein abundance predictions, machine learning models were trained that integrate features derived from protein-constrained modelling and codon usage. Combining the two types of features outperformed single feature models and yielded good prediction results without relying on experimental transcriptomic data. The presented work reports valuable advances in the prediction of enzyme allocation in unseen scenarios using protein constrained metabolic models. It marks the first successful application of this modelling framework in the biotechnological important taxon of green microalgae, substantially increasing our knowledge of the enzyme catalytic landscape of phototrophic microorganisms.},
  language  = {en}
}
@phdthesis{Schauer2024,
  author    = {Schauer, Lina Marie},
  title     = {Reputation auf Online-Plattformen},
  series = {Datenrecht und neue Technologien},
  volume    = {10},
  journal   = {Datenrecht und neue Technologien},
  edition   = {1},
  publisher = {Nomos},
  address   = {Baden-Baden},
  isbn      = {978-3-7560-1720-1},
  issn      = {2749-7534},
  doi       = {10.5771/9783748944492},
  pages     = {384},
  year      = {2024},
  abstract  = {Wie ist der „gute Ruf" von Unternehmen und Einzelpersonen im Umfeld von Online-Bewertungsplattformen gesch{\"u}tzt? Das Werk erforscht, ob und inwieweit das geltende Recht einen ad{\"a}quaten und l{\"u}ckenlosen Schutz f{\"u}r die unternehmerische und personelle Reputation gew{\"a}hrleitstet. Die Systematisierung und Untersuchung des bestehenden Regelungsgef{\"u}ges konzentriert sich auf das Lauterkeitsrecht und das allgemeine Deliktsrecht unter besonderer Ber{\"u}cksichtigung der rechtlichen Innovationen auf nationaler (UWG-Reform 2022) und europ{\"a}ischer (New Deal for Consumers, Digital Services Act) Ebene. Die Dissertation wurde f{\"u}r den ›Justizpreis Berlin-Brandenburg - Carl Gottlieb Svarez 2024‹ vorgeschlagen.},
  language  = {de}
}
@phdthesis{Mayer2024,
  author    = {Mayer, Selina},
  title     = {Understanding the impact of design thinking on organizations and individuals},
  doi       = {10.25932/publishup-65154},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-651541},
  school      = {Universit{\"a}t Potsdam},
  pages     = {xi, 125},
  year      = {2024},
  abstract  = {Organizations are investing billions on innovation and agility initiatives to stay competitive in their increasingly uncertain business environments. Design Thinking, an innovation approach based on human-centered exploration, ideation and experimentation, has gained increasing popularity. The market for Design Thinking, including software products and general services, is projected to reach 2.500 million \$ (US-Dollar) by 2028. A dispersed set of positive outcomes have been attributed to Design Thinking. However, there is no clear understanding of what exactly comprises the impact of Design Thinking and how it is created. To support a billion-dollar market, it is essential to understand the value Design Thinking is bringing to organizations not only to justify large investments, but to continuously improve the approach and its application. Following a qualitative research approach combined with results from a systematic literature review, the results presented in this dissertation offer a structured understanding of Design Thinking impact. The results are structured along two main perspectives of impact: the individual and the organizational perspective. First, insights from qualitative data analysis demonstrate that measuring and assessing the impact of Design Thinking is currently one central challenge for Design Thinking practitioners in organizations. Second, the interview data revealed several effects Design Thinking has on individuals, demonstrating how Design Thinking can impact boundary management behaviors and enable employees to craft their jobs more actively. Contributing to innovation management research, the work presented in this dissertation systematically explains the Design Thinking impact, allowing other researchers to both locate and integrate their work better. The results of this research advance the theoretical rigor of Design Thinking impact research, offering multiple theoretical underpinnings explaining the variety of Design Thinking impact. Furthermore, this dissertation contains three specific propositions on how Design Thinking creates an impact: Design Thinking creates an impact through integration, enablement, and engagement. Integration refers to how Design Thinking enables organizations through effectively combining things, such as for example fostering balance between exploitation and exploration activities. Through Engagement, Design Thinking impacts organizations involving users and other relevant stakeholders in their work. Moreover, Design Thinking creates impact through Enablement, making it possible for individuals to enact a specific behavior or experience certain states. By synthesizing multiple theoretical streams into these three overarching themes, the results of this research can help bridge disciplinary boundaries, for example between business, psychology and design, and enhance future collaborative research. Practitioners benefit from the results as multiple desirable outcomes are detailed in this thesis, such as successful individual job crafting behaviors, which can be expected from practicing Design Thinking. This allows practitioners to enact more evidence-based decision-making concerning Design Thinking implementation. Overall, considering multiple levels of impact as well as a broad range of theoretical underpinnings are paramount to understanding and fostering Design Thinking impact.},
  language  = {en}
}
@phdthesis{Heckenbach2024,
  author    = {Heckenbach, Esther Lina},
  title     = {Geodynamic modeling of process interactions at continental plate boundaries},
  doi       = {10.25932/publishup-64750},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-647500},
  school      = {Universit{\"a}t Potsdam},
  pages     = {127},
  year      = {2024},
  abstract  = {Plate tectonic boundaries constitute the suture zones between tectonic plates. They are shaped by a variety of distinct and interrelated processes and play a key role in geohazards and georesource formation. Many of these processes have been previously studied, while many others remain unaddressed or undiscovered. In this work, the geodynamic numerical modeling software ASPECT is applied to shed light on further process interactions at continental plate boundaries. In contrast to natural data, geodynamic modeling has the advantage that processes can be directly quantified and that all parameters can be analyzed over the entire evolution of a structure. Furthermore, processes and interactions can be singled out from complex settings because the modeler has full control over all of the parameters involved. To account for the simplifying character of models in general, I have chosen to study generic geological settings with a focus on the processes and interactions rather than precisely reconstructing a specific region of the Earth. In Chapter 2, 2D models of continental rifts with different crustal thicknesses between 20 and 50 km and extension velocities in the range of 0.5-10 mm/yr are used to obtain a speed limit for the thermal steady-state assumption, commonly employed to address the temperature fields of continental rifts worldwide. Because the tectonic deformation from ongoing rifting outpaces heat conduction, the temperature field is not in equilibrium, but is characterized by a transient, tectonically-induced heat flow signal. As a result, I find that isotherm depths of the geodynamic evolution models are shallower than a temperature distribution in equilibrium would suggest. This is particularly important for deep isotherms and narrow rifts. In narrow rifts, the magnitude of the transient temperature signal limits a well-founded applicability of the thermal steady-state assumption to extension velocities of 0.5-2 mm/yr. Estimation of the crustal temperature field affects conclusions on all temperature-dependent processes ranging from mineral assemblages to the feasible exploitation of a geothermal reservoir. In Chapter 3, I model the interactions of different rheologies with the kinematics of folding and faulting using the example of fault-propagation folds in the Andean fold-and-thrust belt. The evolution of the velocity fields from geodynamic models are compared with those from trishear models of the same structure. While the latter use only geometric and kinematic constraints of the main fault, the geodynamic models capture viscous, plastic, and elastic deformation in the entire model domain. I find that both models work equally well for early, and thus relatively simple stages of folding and faulting, while results differ for more complex situations where off-fault deformation and secondary faulting are present. As fault-propagation folds can play an important role in the formation of reservoirs, knowledge of fluid pathways, for example via fractures and faults, is crucial for their characterization. Chapter 4 deals with a bending transform fault and the interconnections between tectonics and surface processes. In particular, the tectonic evolution of the Dead Sea Fault is addressed where a releasing bend forms the Dead Sea pull-apart basin, while a restraining bend further to the North resulted in the formation of the Lebanese mountains. I ran 3D coupled geodynamic and surface evolution models that included both types of bends in a single setup. I tested various randomized initial strain distributions, showing that basin asymmetry is a consequence of strain localization. Furthermore, by varying the surface process efficiency, I find that the deposition of sediment in the pull-apart basin not only controls basin depth, but also results in a crustal flow component that increases uplift at the restraining bend. Finally, in Chapter 5, I present the computational basis for adding further complexity to plate boundary models in ASPECT with the implementation of earthquake-like behavior using the rate-and-state friction framework. Despite earthquakes happening on a relatively small time scale, there are many interactions between the seismic cycle and the long time spans of other geodynamic processes. Amongst others, the crustal state of stress as well as the presence of fluids or changes in temperature may alter the frictional behavior of a fault segment. My work provides the basis for a realistic setup of involved structures and processes, which is therefore important to obtain a meaningful estimate for earthquake hazards. While these findings improve our understanding of continental plate boundaries, further development of geodynamic software may help to reveal even more processes and interactions in the future.},
  language  = {en}
}
@phdthesis{Mirzaee2024,
  author    = {Mirzaee, Zohreh},
  title     = {Ecology and phylogeny of Mantodea of Iran and adjacent areas},
  doi       = {10.25932/publishup-65273},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-652739},
  school      = {Universit{\"a}t Potsdam},
  pages     = {187},
  year      = {2024},
  abstract  = {Mantodea, commonly known as mantids, have captivated researchers owing to their enigmatic behavior and ecological significance. This order comprises a diverse array of predatory insects, boasting over 2,400 species globally and inhabiting a wide spectrum of ecosystems. In Iran, the mantid fauna displays remarkable diversity, yet numerous facets of this fauna remain poorly understood, with a significant dearth of systematic and ecological research. This substantial knowledge gap underscores the pressing need for a comprehensive study to advance our understanding of Mantodea in Iran and its neighboring regions. The principal objective of this investigation was to delve into the ecology and phylogeny of Mantodea within these areas. To accomplish this, our research efforts concentrated on three distinct genera within Iranian Mantodea. These genera were selected due to their limited existing knowledge base and feasibility for in-depth study. Our comprehensive methodology encompassed a multifaceted approach, integrating morphological analysis, molecular techniques, and ecological observations. Our research encompassed a comprehensive revision of the genus Holaptilon, resulting in the description of four previously unknown species. This extensive effort substantially advanced our understanding of the ecological roles played by Holaptilon and refined its systematic classification. Furthermore, our investigation into Nilomantis floweri expanded its known distribution range to include Iran. By conducting thorough biological assessments, genetic analyses, and ecological niche modeling, we obtained invaluable insights into distribution patterns and genetic diversity within this species. Additionally, our research provided a thorough comprehension of the life cycle, behaviors, and ecological niche modeling of Blepharopsis mendica, shedding new light on the distinctive characteristics of this mantid species. Moreover, we contributed essential knowledge about parasitoids that infect mantid ootheca, laying the foundation for future studies aimed at uncovering the intricate mechanisms governing ecological and evolutionary interactions between parasitoids and Mantodea.},
  language  = {en}
}
@phdthesis{Mielke2024,
  author    = {Mielke, Lucas},
  title     = {Schernikau und die Poetik der Affirmation},
  series = {Deutsche Literatur : Studien und Quellen},
  volume    = {48},
  journal   = {Deutsche Literatur : Studien und Quellen},
  publisher = {De Gruyter},
  address   = {Berlin ; Boston, Mass},
  isbn      = {9783111441221},
  issn      = {2198-932X},
  doi       = {10.1515/9783111441221},
  pages     = {vi; 241},
  year      = {2024},
  abstract  = {Die Arbeit ist der Versuch einer zusammenh{\"a}ngenden historisierenden Lekt{\"u}re der wichtigsten Essays und fiktionalen Prosatexte des Schriftstellers Ronald M. Schernikau (1960-1991). Der schwule Kommunist erkl{\"a}rte das Lob zur k{\"u}nstlerischen Strategie, formulierte gleichzeitig eine avancierte Gesellschaftskritik und verteidigte den realen Sozialismus auch gegen die Realit{\"a}t. Im Verlauf mehrerer Einzelstudien werden Themen, Schreibweisen und schließlich auch die Widerspr{\"u}che, in die sich ein solches Projekt verstricken muss, analysiert. Vor dem Hintergrund zentraler politischer und {\"a}sthetischer Debatten der 1970er und -80er Jahre werden so die Umrisse einer politischen Poetik nachgezeichnet, die der Sch{\"o}nheit verpflichtet ist. Ein weiteres Augenmerk liegt dabei auf theorie- und bewegungsgeschichtlichen Aspekten. Gibt es ein schwules Schreiben jenseits einer auktorialen Selbstpositionierung? Was w{\"u}rde eine kommunistische Literatur auszeichnen? Schernikau verhandelt poetologische Fragen um die Konzepte Autorschaft, Realismus und Werk, die nicht nur an gegenw{\"a}rtige Diskurse anschlussf{\"a}hig sind, sondern auf die Kernprobleme der politischen Literatur des Zwanzigsten Jahrhunderts verweisen.},
  language  = {de}
}
@phdthesis{Shigeyama2024,
  author    = {Shigeyama, Jotaro},
  title     = {Virtual reality at 1:1 scale in small physical spaces},
  doi       = {10.25932/publishup-64900},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-649000},
  school      = {Universit{\"a}t Potsdam},
  pages     = {115},
  year      = {2024},
  abstract  = {Virtual Reality (VR) leads to the highest level of immersion if presented using a 1:1 mapping of virtual space to physical space—also known as real walking. The advent of inexpensive consumer virtual reality (VR) headsets, all capable of running inside-out position tracking, has brought VR to the home. However, many VR applications do not feature full real walking, but instead, feature a less immersive space-saving technique known as instant teleportation. Given that only 0.3\% of home users run their VR experiences in spaces more than 4m2, the most likely explanation is the lack of the physical space required for meaningful use of real walking. In this thesis, we investigate how to overcome this hurdle. We demonstrate how to run 1:1-mapped VR experiences in small physical spaces and we explore the trade-off between space and immersion. (1) We start with a space limit of 15cm. We present DualPanto, a device that allows (blind) VR users to experience the virtual world from a 1:1 mapped bird's eye perspective—by leveraging haptics. (2) We then relax our space constraints to 50cm, which is what seated users (e.g., on an airplane or train ride) have at their disposal. We leverage the space to represent a standing user in 1:1 mapping, while only compressing the user's arm movement. We demonstrate our 4 prototype VirtualArms at the example of VR experiences limited to arm movement, such as boxing. (3) Finally, we relax our space constraints further to 3m2 of walkable space, which is what 75\% of home users have access to. As well- established in the literature, we implement real walking with the help of portals, also known as "impossible spaces". While impossible spaces on such dramatic space constraints tend to degenerate into incomprehensible mazes (as demonstrated, for example, by "TraVRsal"), we propose plausibleSpaces: presenting meaningful virtual worlds by adapting various visual elements to impossible spaces. Our techniques push the boundary of spatially meaningful VR interaction in various small spaces. We see further future challenges for new design approaches to immersive VR experiences for the smallest physical spaces in our daily life.},
  language  = {en}
}
@phdthesis{Odanga2024,
  author    = {Odanga, Denish Otieno},
  title     = {Phobic cosmopolitanism},
  school      = {Universit{\"a}t Potsdam},
  pages     = {vi ; 211},
  year      = {2024},
  language  = {en}
}
@phdthesis{Kaun2024,
  author    = {Kaun, Mario},
  title     = {Begrenztes Cottbus?},
  series = {Schriften des Fr{\"u}hneuzeitzentrums Potsdam},
  volume    = {13},
  journal   = {Schriften des Fr{\"u}hneuzeitzentrums Potsdam},
  publisher = {V \& R Unipress},
  address   = {G{\"o}ttingen},
  isbn      = {978-3-8471-1726-1},
  issn      = {2198-5251},
  pages     = {311},
  year      = {2024},
  abstract  = {In diesem Band erm{\"o}glicht Mario Kaun ausgew{\"a}hlte Einblicke in die Lebenswelt der Cottbuser Exklavengesellschaft des 18. Jahrhunderts. Erstmalig erscheint hiermit f{\"u}r diesen Untersuchungsraum eine grundlegende Studie, die in umfassender Weise die Exklave und das Verh{\"a}ltnis von Milit{\"a}r und Gesellschaft n{\"a}her erforscht sowie die wirtschaftliche Funktion der Garnison in einer aufstrebenden Stadt kritisch hinterfragt. Der Autor lenkt hierbei das Augenmerk auf etliche, bisher v{\"o}llig unbekannte Perspektiven, die dar{\"u}ber hinaus einen wichtigen Beitrag zur Stadt- und Regionalgeschichtsforschung von Cottbus und der Niederlausitz leisten. Insbesondere die Befassung mit der brandenburgisch-preußischen Exklave stellt eine wertvolle Erg{\"a}nzung zur bislang rudiment{\"a}ren Forschungslage dar.},
  language  = {de}
}
@phdthesis{Karakas2024,
  author    = {Karakas, Esra},
  title     = {High-resolution studies of epistasis in tomato metabolism},
  school      = {Universit{\"a}t Potsdam},
  pages     = {137},
  year      = {2024},
  abstract  = {The inclusion of exotic germplasm serves as a crucial means to enhance allelic and consequently phenotypic diversity in inbred crop species. Such species have experienced a reduction in diversity due to artificial selection focused on a limited set of traits. The natural biodiversity within ecosystems presents an opportunity to explore various traits influencing plant survival, reproductive fitness and yield potential. In agricultural research, the study of wild species closely related to cultivated plants serves as a means to comprehend the genetic foundations of past domestication events and the polymorphisms essential for future breeding efforts to develop superior varieties. In order to examine the metabolic composition, pinpoint quantitative trait loci (QTL) and facilitate their resolution an extensive large-scale analysis of metabolic QTL (mQTL) was conducted on tomato backcross inbred lines (BILs) derived from a cross between the wild species S. pennellii (5240) incorporated into the background of S. lycopersicum cv. LEA determinate inbred which can be grown in open fields and cv. TOP indeterminate which can be grown in greenhouse conditions. A large number of mQTL associated with primary secondary and lipid metabolism in fruit were identified across the two BIL populations. Epistasis, the interactions between genes at different loci, has been an interest in molecular and quantitative genetics for many decades. The study of epistasis requires the analysis of very large populations with multiple independent genotypes that carry specific genomic regions. In order to understand the genetic basis of tomato fruit metabolism, I extended the work to investigate epistatic interactions of the genomic regions. In addition, two candidate genes were identified through quantitative trait loci underlying fruit-specific sucrose and jasmonic acid derivatives. Finally, in this study, I assessed the genetic framework of fruit metabolic traits with a high level of detail, utilizing the newly created Solanum pennellii (5240) backcrossed introgression lines (n=3000). This investigation resulted in the discovery of promising candidate loci associated with significant fruit quality traits, including those to the abundance of glutamic acid and aspartic acid crucial elements contributing to the development of acidity and flavors.},
  language  = {en}
}
@phdthesis{Bryant2024,
  author    = {Bryant, Seth},
  title     = {Aggregation and disaggregation in flood risk models},
  doi       = {10.25932/publishup-65095},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-650952},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ix, 116},
  year      = {2024},
  abstract  = {Floods continue to be the leading cause of economic damages and fatalities among natural disasters worldwide. As future climate and exposure changes are projected to intensify these damages, the need for more accurate and scalable flood risk models is rising. Over the past decade, macro-scale flood risk models have evolved from initial proof-of-concepts to indispensable tools for decision-making at global-, nationaland, increasingly, the local-level. This progress has been propelled by the advent of high-performance computing and the availability of global, space-based datasets. However, despite such advancements, these models are rarely validated and consistently fall short of the accuracy achieved by high-resolution local models. While capabilities have improved, significant gaps persist in understanding the behaviours of such macro-scale models, particularly their tendency to overestimate risk. This dissertation aims to address such gaps by examining the scale transfers inherent in the construction and application of coarse macroscale models. To achieve this, four studies are presented that, collectively, address exposure, hazard, and vulnerability components of risk affected by upscaling or downscaling. The first study focuses on a type of downscaling where coarse flood hazard inundation grids are enhanced to a finer resolution. While such inundation downscaling has been employed in numerous global model chains, ours is the first study to focus specifically on this component, providing an evaluation of the state of the art and a novel algorithm. Findings demonstrate that our novel algorithm is eight times faster than existing methods, offers a slight improvement in accuracy, and generates more physically coherent flood maps in hydraulically challenging regions. When applied to a case study, the algorithm generated a 4m resolution inundation map from 30m hydrodynamic model outputs in 33 s, a 60-fold improvement in runtime with a 25\% increase in RMSE compared with direct hydrodynamic modelling. All evaluated downscaling algorithms yielded better accuracy than the coarse hydrodynamic model when compared to observations, demonstrating similar limits of coarse hydrodynamic models reported by others. The substitution of downscaling into flood risk model chains, in place of high-resolution modelling, can drastically improve the lead time of impactbased forecasts and the efficiency of hazard map production. With downscaling, local regions could obtain high resolution local inundation maps by post-processing a global model without the need for expensive modelling or expertise. The second study focuses on hazard aggregation and its implications for exposure, investigating implicit aggregations commonly used to intersect hazard grids with coarse exposure models. This research introduces a novel spatial classification framework to understand the effects of rescaling flood hazard grids to a coarser resolution. The study derives closed-form analytical solutions for the location and direction of bias from flood grid aggregation, showing that bias will always be present in regions near the edge of inundation. For example, inundation area will be positively biased when water depth grids are aggregated, while volume will be negatively biased when water elevation grids are aggregated. Extending the analysis to effects of hazard aggregation on building exposure, this study shows that exposure in regions at the edge of inundation are an order of magnitude more sensitive to aggregation errors than hazard alone. Among the two aggregation routines considered, averaging water surface elevation grids better preserved flood depths at buildings than averaging of water depth grids. The study provides the first mathematical proof and generalizeable treatment of flood hazard grid aggregation, demonstrating important mechanisms to help flood risk modellers understand and control model behaviour. The final two studies focus on the aggregation of vulnerability models or flood damage functions, investigating the practice of applying per-asset functions to aggregate exposure models. Both studies extend Jensen's inequality, a well-known 1906 mathematical proof, to demonstrate how the aggregation of flood damage functions leads to bias. Applying Jensen's proof in this new context, results show that typically concave flood damage functions will introduce a positive bias (overestimation) when aggregated. This behaviour was further investigated with a simulation experiment including 2 million buildings in Germany, four global flood hazard simulations and three aggregation scenarios. The results show that positive aggregation bias is not distributed evenly in space, meaning some regions identified as "hot spots of risk" in assessments may in fact just be hot spots of aggregation bias. This study provides the first application of Jensen's inequality to explain the overestimates reported elsewhere and advice for modellers to minimize such artifacts. In total, this dissertation investigates the complex ways aggregation and disaggregation influence the behaviour of risk models, focusing on the scale-transfers underpinning macro-scale flood risk assessments. Extending a key finding of the flood hazard literature to the broader context of flood risk, this dissertation concludes that all else equal, coarse models overestimate risk. This dissertation goes beyond previous studies by providing mathematical proofs for how and where such bias emerges in aggregation routines, offering a mechanistic explanation for coarse model overestimates. It shows that this bias is spatially heterogeneous, necessitating a deep understanding of how rescaling may bias models to effectively reduce or communicate uncertainties. Further, the dissertation offers specific recommendations to help modellers minimize scale transfers in problematic regions. In conclusion, I argue that such aggregation errors are epistemic, stemming from choices in model structure, and therefore hold greater potential and impetus for study and mitigation. This deeper understanding of uncertainties is essential for improving macro-scale flood risk models and their effectiveness in equitable, holistic, and sustainable flood management.},
  language  = {en}
}
@phdthesis{Reuss2024,
  author    = {Reuß, Maximilian},
  title     = {Laborexperimente, {\"U}berwachung und Simulation einer reaktiven Wand zur Abreinigung von eisen- und sulfathaltigen Bergbauw{\"a}ssern bei sauren und neutralen pH-Bedingungen},
  doi       = {10.25932/publishup-64856},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-648564},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XIV, 126, LXI},
  year      = {2024},
  abstract  = {In dieser Arbeit wurde eine reaktive Wand in einem kleinskaligen Laborma\ss stab (L{\"a}nge~=~40\,cm) entwickelt, die Eisen- und Sulfatbelastungen aus sauren Minenabw{\"a}ssern (engl. \textit{acid mine drainage} (AMD)) mit einer Effizienz von bis zu 30.2 bzw. 24.2\,\\% {\"u}ber einen Zeitraum von 146~Tagen (50\,pv) abreinigen k{\"o}nnen sollte. Als reaktives Material wurde eine Mischung aus Gartenkompost, Buchenholz, Kokosnussschale und Calciumcarbonat verwendet. Die Zugabebedingungen waren eine Eisenkonzentration von 1000\,mg/L, eine Sulfatkonzentration von 3000\,mg/L und ein pH-Wert von 6.2. Unterschiede in der Materialzusammensetzung ergaben keine gr{\"o}\ss eren {\"A}nderungen in der Sanierungseffizienz von Eisen- und Sulfatbelastungen (12.0 -- 15.4\,\\% bzw. 7.0 -- 10.1\,\\%) {\"u}ber einen Untersuchungszeitraum von 108~Tagen (41 -- 57\,pv). Der wichtigste Einflussfaktor auf die Abreinigungsleistung von Sulfat- und Eisenbelastungen war die Verweilzeit der AMD-L{\"o}sung im reaktiven Material. Diese kann durch eine Verringerung des Durchflusses oder eine Erh{\"o}hung der L{\"a}nge der reaktiven Wand (engl. \textit{Permeable Reactive Barrier} (PRB)) erh{\"o}ht werden. Ein halbierter Durchfluss erh{\"o}hte die Sanierungseffizienzen von Eisen und Sulfat auf 23.4 bzw. 32.7\,\\%. Weiterhin stieg die Sanierungseffizienz der Eisenbelastungen auf 24.2\,\\% bei einer Erh{\"o}hung der Sulfatzugabekonzentration auf 6000\,mg/L. Saure Startbedingungen (pH~=~2.2) konnten, durch das Calciumcarbonat im reaktiven Material, {\"u}ber einen Zeitraum von 47~Tagen (24\,pv) neutralisiert werden. Durch die Neutralisierung der sauren Startbedingungen wurde Calciumcarbonat in der \gls{prb} verbraucht und Calcium-Ionen freigesetzt, die die Sulfatsanierungseffizienz erh{\"o}ht haben (24.9\,\\%). Aufgrund einer Vergr{\"o}\ss erung der \gls{prb} in Breite und Tiefe und einer 2D-Parameterbestimmung konnten Randl{\"a}ufigkeiten beobachtet werden, ohne deren Einfluss sich die Sanierungseffizienz f{\"u}r Eisen- und Sulfatbelastungen erh{\"o}ht (30.2 bzw. 24.2\,\\%). \par Zur \textit{in-situ} {\"U}berwachung der \gls{prb} wurden optische Sensoren verwendet, um den pH-Wert, die Sauerstoffkonzentration und die Temperatur zu ermitteln. Es wurden, nach dem Ort und der Zeit aufgel{\"o}st, stabile Sauerstoffkonzentrationen und pH-Verl{\"a}ufe detektiert. Auch die Temperatur konnte nach dem Ort aufgel{\"o}st ermittelt werden. Damit zeigte diese Arbeit, dass optische Sensoren zur {\"U}berwachung der Stabilit{\"a}t einer \gls{prb} f{\"u}r die Reinigung von \gls{amd} verwendet werden k{\"o}nnen. \par Mit dem Simulationsprogramm MIN3P wurde eine Simulation erstellt, die die entwickelte PRB darstellt. Die Simulation kann die erhaltenen Laborergebnisse gut wiedergeben. Anschlie\ss end wurde eine simulierte \gls{prb} bei unterschiedlichen Filtergeschwindigkeiten ((4.0 -- 23.5)~\$\cdot~\mathrm{10^{-7}}\$\,m/s) und L{\"a}ngen der PRB (25 -- 400\,cm) untersucht. Es wurden Zusammenh{\"a}nge der untersuchten Parameter mit der Sanierungseffizienz von Eisen- und Sulfatbelastungen ermittelt. Diese Zusammenh{\"a}nge k{\"o}nnen verwendet werden, um die ben{\"o}tigte Verweilzeit der AMD-L{\"o}sung in einem zuk{\"u}nftigen PRB-System, die f{\"u}r die maximal m{\"o}gliche Sanierungsleistung notwendig ist, zu berechnen.},
  language  = {de}
}
@phdthesis{Kindermann2024,
  author    = {Kindermann, Liana},
  title     = {Trees, shrubs, and land-use change},
  doi       = {10.25932/publishup-64894},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-648943},
  school      = {Universit{\"a}t Potsdam},
  pages     = {X, 186},
  year      = {2024},
  abstract  = {The global drylands cover nearly half of the terrestrial surface and are home to more than two billion people. In many drylands, ongoing land-use change transforms near-natural savanna vegetation to agricultural land to increase food production. In Southern Africa, these heterogenous savanna ecosystems are also recognized as habitats of many protected animal species, such as elephant, lion and large herds of diverse herbivores, which are of great value for the tourism industry. Here, subsistence farmers and livestock herder communities often live in close proximity to nature conservation areas. Although these land-use transformations are different regarding the future they aspire to, both processes, nature conservation with large herbivores and agricultural intensification, have in common, that they change the vegetation structure of savanna ecosystems, usually leading to destruction of trees, shrubs and the woody biomass they consist of. Such changes in woody vegetation cover and biomass are often regarded as forms of land degradation and forest loss. Global forest conservation approaches and international programs aim to stop degradation processes, also to conserve the carbon bound within wood from volatilization into earth's atmosphere. In search for mitigation options against global climate change savannas are increasingly discussed as potential carbon sinks. Savannas, however, are not forests, in that they are naturally shaped by and adapted to disturbances, such as wildfires and herbivory. Unlike in forests, disturbances are necessary for stable, functioning savanna ecosystems and prevent these ecosystems from forming closed forest stands. Their consequently lower levels of carbon storage in woody vegetation have long been the reason for savannas to be overlooked as a potential carbon sink but recently the question was raised if carbon sequestration programs (such as REDD+) could also be applied to savanna ecosystems. However, heterogenous vegetation structure and chronic disturbances hamper the quantification of carbon stocks in savannas, and current procedures of carbon storage estimation entail high uncertainties due to methodological obstacles. It is therefore challenging to assess how future land-use changes such as agricultural intensification or increasing wildlife densities will impact the carbon storage balance of African drylands. In this thesis, I address the research gap of accurately quantifying carbon storage in vegetation and soils of disturbance-prone savanna ecosystems. I further analyse relevant drivers for both ecosystem compartments and their implications for future carbon storage under land-use change. Moreover, I show that in savannas different carbon storage pools vary in their persistence to disturbance, causing carbon bound in shrub vegetation to be most likely to experience severe losses under land-use change while soil organic carbon stored in subsoils is least likely to be impacted by land-use change in the future. I start with summarizing conventional approaches to carbon storage assessment and where and for which reasons they fail to accurately estimated savanna ecosystem carbon storage. Furthermore, I outline which future-making processes drive land-use change in Southern Africa along two pathways of land-use transformation and how these are likely to influence carbon storage. In the following chapters, I propose a new method of carbon storage estimation which is adapted to the specific conditions of disturbance-prone ecosystems and demonstrate the advantages of this approach in relation to existing forestry methods. Specifically, I highlight sources for previous over- and underestimation of savanna carbon stocks which the proposed methodology resolves. In the following chapters, I apply the new method to analyse impacts of land-use change on carbon storage in woody vegetation in conjunction with the soil compartment. With this interdisciplinary approach, I can demonstrate that indeed both, agricultural intensification and nature conservation with large herbivores, reduce woody carbon storage above- and belowground, but partly sequesters this carbon into the soil organic carbon stock. I then quantify whole-ecosystem carbon storage in different ecosystem compartments (above- and belowground woody carbon in shrubs and trees, respectively, as well as topsoil and subsoil organic carbon) of two savanna vegetation types (scrub savanna and savanna woodland). Moreover, in a space-for-time substitution I analyse how land-use changes impact carbon storage in each compartment and in the whole ecosystem. Carbon storage compartments are found to differ in their persistence to land-use change with carbon bound in shrub biomass being least persistent to future changes and subsoil organic carbon being most stable under changing land-use. I then explore which individual land-use change effects act as drivers of carbon storage through Generalized Additive Models (GAMs) and uncover non-linear effects, especially of elephant browsing, with implications for future carbon storage. In the last chapter, I discuss my findings in the larger context of this thesis and discuss relevant implications for land-use change and future-making decisions in rural Africa.},
  language  = {en}
}
@phdthesis{NovakovicMarinkovic2024,
  author    = {Novakovic-Marinkovic, Nina},
  title     = {Optical control of bubble domains and skyrmions in thin films},
  doi       = {10.25932/publishup-64706},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-647069},
  school      = {Universit{\"a}t Potsdam},
  pages     = {ii, 106},
  year      = {2024},
  abstract  = {Laser induced switching offers an attractive possibility to manipulate small magnetic domains for prospective memory and logic devices on ultrashort time scales. Moreover, optical control of magnetization without high applied magnetic fields allows manipulation of magnetic domains individually and locally, without expensive heat dissipation. One of the major challenges for developing novel optically controlled magnetic memory and logic devices is reliable formation and annihilation of non-volatile magnetic domains that can serve as memory bits in ambient conditions. Magnetic skyrmions, topologically nontrivial spin textures, have been studied intensively since their discovery due to their stability and scalability in potential spintronic devices. However, skyrmion formation and, especially, annihilation processes are still not completely understood and further investigation on such mechanisms are needed. The aim of this thesis is to contribute to better understanding of the physical processes behind the optical control of magnetism in thin films, with the goal of optimizing material parameters and methods for their potential use in next generation memory and logic devices. First part of the thesis is dedicated to investigation of all-optical helicity-dependent switching (AO-HDS) as a method for magnetization manipulation. AO-HDS in Co/Pt multilayer and CoFeB alloys with and without the presence of Dzyaloshinskii-Moriya interaction (DMI), which is a type of exchange interaction, have been investigated by magnetic imaging using photo-emission electron microscopy (PEEM) in combination with X-ray magnetic circular dichroism (XMCD). The results show that in a narrow range of the laser fluence, circularly polarized laser light induces a drag on domain walls. This enables a local deterministic transformation of the magnetic domain pattern from stripes to bubbles in out-of-plane magnetized Co/Pt multilayers, only controlled by the helicity of ultrashort laser pulses. The temperature and characteristic fields at which the stripe-bubble transformation occurs has been calculated using theory for isolated magnetic bubbles, using as parameters experimentally determined average size of stripe domains and the magnetic layer thickness. The second part of the work aims at purely optical formation and annihilation of magnetic skyrmions by a single laser pulse. The presence of a skyrmion phase in the investigated CoFeB alloys was first confirmed using a Kerr microscope. Then the helicity-dependent skyrmion manipulation was studied using AO-HDS at different laser fluences. It was found that formation or annihilation individual skyrmions using AO-HDS is possible, but not always reliable, as fluctuations in the laser fluence or position can easily overwrite the helicity-dependent effect of AO-HDS. However, the experimental results and magnetic simulations showed that the threshold values for the laser fluence for the formation and annihilation of skyrmions are different. A higher fluence is required for skyrmion formation, and existing skyrmions can be annihilated by pulses with a slightly lower fluence. This provides a further option for controlling formation and annihilation of skyrmions using the laser fluence. Micromagnetic simulations provide additional insights into the formation and annihilation mechanism. The ability to manipulate the magnetic state of individual skyrmions is of fundamental importance for magnetic data storage technologies. Our results show for the first time that the optical formation and annihilation of skyrmions is possible without changing the external field. These results enable further investigations to optimise the magnetic layer to maximise the energy gap between the formation and annihilation barrier. As a result, unwanted switching due to small laser fluctuations can be avoided and fully deterministic optical switching can be achieved.},
  language  = {en}
}
@phdthesis{Kucharzewski2024,
  author    = {Kucharzewski, Tim},
  title     = {Wars and the world},
  publisher = {Cambridge Scholars Publishing},
  address   = {Newcastle upon Tyne},
  isbn      = {978-1-0364-0374-4},
  pages     = {xxi, 509},
  year      = {2024},
  abstract  = {This book offers a descriptive analysis of the Soviet/Russian wars in Afghanistan, Chechnya, and Georgia, as well as an in-depth exploration of the ways in which these wars are framed in the collective consciousness created by global popular culture. Russian and Western modalities of remembrance have been, and remain, engaged in a world war that takes place (not exclusively, but intensively) on the level of popular culture. The action/reaction dynamic, confrontational narratives and othering between the two "camps" never ceased. The Cold War, in many ways and contrary to the views of many others who hoped for the end of history, never really ended.},
  language  = {en}
}
@phdthesis{Friese2024,
  author    = {Friese, Sharleen},
  title     = {Trace elements and genomic instability in the murine brain},
  school      = {Universit{\"a}t Potsdam},
  pages     = {XV, 112, XXI},
  year      = {2024},
  abstract  = {The trace elements copper, iron, manganese, selenium and zinc are essential micronutrients involved in various cellular processes, all with different responsibilities. Based on that importance, their concentrations are tightly regulated in mammalian organisms. The maintenance of those levels is termed trace element homeostasis and mediated by a combination of processes regulating absorption, cellular and systemic transport mechanisms, storage and effector proteins as well as excretion. Due to their chemical properties, some functions of trace elements overlap, as seen in antioxidative defence, for example, comprising an expansive spectrum of antioxidative proteins and molecules. Simultaneously, the same is true for regulatory mechanisms, causing trace elements to influence each other's homeostases. To mimic physiological conditions, trace elements should therefore not be evaluated separately but considered in parallel. While many of these homeostatic mechanisms are well-studied, for some elements new pathways are still discovered. Additionally, the connections between dietary trace element intake, trace element status and health are not fully unraveled, yet. With current demographic developments, also the influence of ageing as well as of certain pathological conditions is of increasing interest. Here, the TraceAge research unit was initiated, aiming to elucidate the homeostases of and interactions between essential trace elements in healthy and diseased elderly. While human cohort studies can offer insights into trace element profiles, also in vivo model organisms are used to identify underlying molecular mechanisms. This is achieved by a set of feeding studies including mice of various age groups receiving diets of reduced trace element content. To account for cognitive deterioration observed with ageing, neurodegenerative diseases, as well as genetic mutations triggering imbalances in cerebral trace element concentrations, one TraceAge work package focuses on trace elements in the murine brain, specifically the cerebellum. In that context, concentrations of the five essential trace elements of interest, copper, iron, manganese, selenium and zinc, were quantified via inductively coupled plasma-tandem mass spectrometry, revealing differences in priority of trace element homeostases between brain and liver. Upon moderate reduction of dietary trace element supply, cerebellar concentrations of copper and manganese deviated from those in adequately supplied animals. By further reduction of dietary trace element contents, also concentrations of cerebellar iron and selenium were affected, but not as strong as observed in liver tissue. In contrast, zinc concentrations remained stable. Investigation of aged mice revealed cerebellar accumulation of copper and iron, possibly contributing to oxidative stress on account of their redox properties. Oxidative stress affects a multitude of cellular components and processes, among them, next to proteins and lipids, also the DNA. Direct insults impairing its integrity are of relevance here, but also indirect effects, mediated by the machinery ensuring genomic stability and its functionality. The system includes the DNA damage response, comprising detection of endogenous and exogenous DNA lesions, decision on subsequent cell fate and enabling DNA repair, which presents another pillar of genomic stability maintenance. Also in proteins of this machinery, trace elements act as cofactors, shaping the hypothesis of impaired genomic stability maintenance under conditions of disturbed trace element homeostasis. To investigate this hypothesis, a variety of approaches was used, applying OECD guidelines Organisation for Economic Co-operation and Development, adapting existing protocols for use in cerebellum tissue and establishing new methods. In order to assess the impact of age and dietary trace element depletion on selected endpoints estimating genomic instability, DNA damage and DNA repair were investigated. DNA damage analysis, in particular of DNA strand breaks and oxidatively modified DNA bases, revealed stable physiological levels which were neither affected by age nor trace element supply. To examine whether this is a result of increased repair rates, two steps characteristic for base excision repair, namely DNA incision and ligation activity, were studied. DNA glycosylases and DNA ligases were not reduced in their activity by age or trace element depletion, either. Also on the level of gene expression, major proteins involved in genomic stability maintenance were analysed, mirroring results obtained from protein studies. To conclude, the present work describes homeostatic regulation of trace elements in the brain, which, in absence of genetic mutations, is able to retain physiological levels even under conditions of reduced trace element supply to a certain extent. This is reflected by functionality of genomic stability maintenance mechanisms, illuminating the prioritization of the brain as vital organ.},
  language  = {en}
}