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In 2022, there were 4.62 billion social media users worldwide. Social media generates a wealth of data which migration scholars have recently started to explore in pursuit of a variety of methodological and thematic research questions. Scholars use social media data to estimate migration stocks, forecast migration flows, or recruit migrants for targeted online surveys. Social media has also been used to understand how migrants get information about their planned journeys and destination countries, how they organize and mobilize online, how migration issues are politicized online, and how migrants integrate culturally into destination countries by sharing common interests. While social media data drives innovative research, it also poses severe challenges regarding data privacy, data protection, and methodological questions relating to external validity. In this chapter, I briefly introduce various strands of migration research using social media data and discuss the advantages, disadvantages, and opportunities.
Enhancing higher entrepreneurship education: insights from practitioners for curriculum improvement
(2024)
Curricula for higher entrepreneurship education should meet the requirements of both a solid theoretical foundation and a practical orientation. When these curricula are designed by education specialists, entrepreneurs are usually not consulted. To explore practitioners’ curricular recommendations, we conducted 73 semi-structured interviews with entrepreneurs with at least five years of professional experience. We collected 49 items for teaching and learning objectives, 37 for contents, 28 for teaching methods, and 17 for assessment methods. The respondents are convinced that students should acquire solid knowledge in business and management, legal issues, and entrepreneurship. For the latter, only some core aspects are provided. The entrepreneurs put greater emphasis on entrepreneurial skills and attitudes and consider experiential learning designs as most suitable, both in the secure setting of the classroom and in real life. The findings can help reflect on current entrepreneurship curriculum designs.
Existing curricula for entrepreneurship education do not necessarily represent the best way of teaching. How could entrepreneurship curricula be improved? To answer this question, we aim to identify and rank desirable teaching objectives, teaching contents, teaching methods, and assessment methods for higher entrepreneurship education. To this end, we employ an international real-time Delphi study with an expert panel consisting of entrepreneurship education instructors and researchers. The study reveals 17 favorable objectives, 17 items of content, 25 teaching methods, and 15 assessment methods, which are ranked according to their desirability and the group consensus. We contribute to entrepreneurship curriculum research by adding a normative perspective.
Germany’s relatively stable party system faces a new left-authoritarian challenger: Sahra Wagenknecht’s Bündnis Sahra Wagenknecht (BSW) party. First polls indicate that for the BSW, election results above 10% are within reach. While Wagenknecht’s positions in economic and cultural terms have already been discussed, this article elaborates on another highly relevant feature of Wagenknecht, namely her populist communication. Exploring Wagenknecht’s and BSW’s populist appeal helps us to understand why the party is said to also have potential among seemingly different voter groups coming from the far right Alternative for Germany (AfD) and far left Die Linke, which share high levels of populist attitudes. To analyse the role that populist communication plays for Wagenknecht and the BSW, this article combines quantitative and qualitative methods. The quantitative analysis covers all speeches (10,000) and press releases (19,000) published by Die Linke members of Parliament (MPs; 2005–2023). The results show that Wagenknecht is the (former) Die Linke MP with the highest share of populist communication. Furthermore, she was also able to convince a group of populist MPs to join the BSW. The article closes with a qualitative analysis of BSW’s manifesto that reveals how populist framing plays a major role in this document, in which the political and economic elites are accused of working against the interest of “the majority”. Based on this analysis, the classification of the BSW as a populist party seems to be appropriate.
A new challenger seeks to enter the German party system: Bündnis Sahra Wagenknecht (BSW). With her new party, former Die Linke politician Sahra Wagenknecht combines a left-authoritarian profile (economically left-leaning, but culturally conservative) with anti-US, pro-Russia and anti-elitist stances. This article provides the first large-n academic study of the voter potential of this new party by using a quasi-representative sample (n = 6,000) drawn from a Voting Advice Application-like dataset that comes from a website designed to explore the Bündnis Sahra Wagenknecht’s positions. The results show that congruence with foreign policy positions and anti-elitism are strong predictors of the propensity to vote for the Bündnis Sahra Wagenknecht. In contrast, social/welfare and immigration policies are less predictive for assessing the party’s potential. Among the different socio-demographic groups, the Bündnis Sahra Wagenknecht has a strong potential among baby boomers, the less educated and East Germans. Regarding party voters, the Bündnis Sahra Wagenknecht is favoured by supporters of some minor parties like dieBasis, Freie Wähler and Die PARTEI, but also non-voters. Among the established parties, the party’s potential is high among Die Linke voters and, to a lesser extent, voters of the Social democrats (SPD) and Alternative for Germany (AfD). A potential below the average is reported for the supporters of the Liberals (FDP) and Christian Democrats (CDU/CSU) and most clearly for Green and Volt voters.
Deep learning has seen widespread application in many domains, mainly for its ability to learn data representations from raw input data. Nevertheless, its success has so far been coupled with the availability of large annotated (labelled) datasets. This is a requirement that is difficult to fulfil in several domains, such as in medical imaging. Annotation costs form a barrier in extending deep learning to clinically-relevant use cases. The labels associated with medical images are scarce, since the generation of expert annotations of multimodal patient data at scale is non-trivial, expensive, and time-consuming. This substantiates the need for algorithms that learn from the increasing amounts of unlabeled data. Self-supervised representation learning algorithms offer a pertinent solution, as they allow solving real-world (downstream) deep learning tasks with fewer annotations. Self-supervised approaches leverage unlabeled samples to acquire generic features about different concepts, enabling annotation-efficient downstream task solving subsequently.
Nevertheless, medical images present multiple unique and inherent challenges for existing self-supervised learning approaches, which we seek to address in this thesis: (i) medical images are multimodal, and their multiple modalities are heterogeneous in nature and imbalanced in quantities, e.g. MRI and CT; (ii) medical scans are multi-dimensional, often in 3D instead of 2D; (iii) disease patterns in medical scans are numerous and their incidence exhibits a long-tail distribution, so it is oftentimes essential to fuse knowledge from different data modalities, e.g. genomics or clinical data, to capture disease traits more comprehensively; (iv) Medical scans usually exhibit more uniform color density distributions, e.g. in dental X-Rays, than natural images. Our proposed self-supervised methods meet these challenges, besides significantly reducing the amounts of required annotations.
We evaluate our self-supervised methods on a wide array of medical imaging applications and tasks. Our experimental results demonstrate the obtained gains in both annotation-efficiency and performance; our proposed methods outperform many approaches from related literature. Additionally, in case of fusion with genetic modalities, our methods also allow for cross-modal interpretability. In this thesis, not only we show that self-supervised learning is capable of mitigating manual annotation costs, but also our proposed solutions demonstrate how to better utilize it in the medical imaging domain. Progress in self-supervised learning has the potential to extend deep learning algorithms application to clinical scenarios.
«Musik erfinden und gestalten» hat grosses musikpädagogisches Potenzial: mit Klängen experimentieren, ein Gespür für dramaturgische Verläufe entwickeln, nonverbal kommunizieren – Musik erfinden und gestalten eröffnet ein breites Feld musikalischer Aktivitäten und Erfahrungsmöglichkeiten. Doch im regulären Musikunterricht in der Volksschule der Schweiz sind produktionsdidaktische Ansätze noch eher die Ausnahme und Musiklehrkräften fehlt es an Anleitungsstrategien.
Für das vorliegende Buch untersuchte der Autor in Form einer Design-based-Research-Studie, wie Primarlehrkräfte ihre Anleitungsstrategien bei der Durchführung von musikalischen Gestaltungsprozessen in ihren Schulklassen schrittweise entwickeln. Dabei begleitete der Forscher die Lehrkräfte in der schulischen Praxis und intervenierte gezielt mit Reflexionsimpulsen, um den Professionalisierungsprozess zu unterstützen.
Daraus wurden drei Reflexionstools generiert: Das Reflexionstool try-outs beinhaltet konkrete Handlungsanregungen und Reflexionsfragen für das Anleiten musikalischer Gestaltungsprozesse. Das Onlinetool improspider ist ein Selbstreflexionsinstrument zur Einschätzung personaler Orientierungen. Das Kompetenzmodell Kompetenzflyer bietet eine Reflexionsfolie für die Ansteuerung eigenständiger Kompetenzerwerbsschritte.
Die Reflexionstools sind außerdem online in Form eines Lernobjekts verfügbar.
Organic solar cells (OSCs) represent a new generation of solar cells with a range of captivating attributes including low-cost, light-weight, aesthetically pleasing appearance, and flexibility. Different from traditional silicon solar cells, the photon-electron conversion in OSCs is usually accomplished in an active layer formed by blending two kinds of organic molecules (donor and acceptor) with different energy levels together.
The first part of this thesis focuses on a better understanding of the role of the energetic offset and each recombination channel on the performance of these low-offset OSCs. By combining advanced experimental techniques with optical and electrical simulation, the energetic offsets between CT and excitons, several important insights were achieved: 1. The short circuit current density and fill-factor of low-offset systems are largely determined by field-dependent charge generation in such low-offset OSCs. Interestingly, it is strongly evident that such field-dependent charge generation originates from a field-dependent exciton dissociation yield. 2. The reduced energetic offset was found to be accompanied by strongly enhanced bimolecular recombination coefficient, which cannot be explained solely by exciton repopulation from CT states. This implies the existence of another dark decay channel apart from CT.
The second focus of the thesis was on the technical perspective. In this thesis, the influence of optical artifacts in differential absorption spectroscopy upon the change of sample configuration and active layer thickness was studied. It is exemplified and discussed thoroughly and systematically in terms of optical simulations and experiments, how optical artifacts originated from non-uniform carrier profile and interference can manipulate not only the measured spectra, but also the decay dynamics in various measurement conditions. In the end of this study, a generalized methodology based on an inverse optical transfer matrix formalism was provided to correct the spectra and decay dynamics manipulated by optical artifacts.
Overall, this thesis paves the way for a deeper understanding of the keys toward higher PCEs in low-offset OSC devices, from the perspectives of both device physics and characterization techniques.
Von Koscher bis Frutarismus
(2024)
Preisalgorithmenkartelle
(2024)
Mithilfe von Preisalgorithmen sind Unternehmen in der Lage, automatische und wechselseitige Preisanpassungen vorzunehmen. Dadurch können klassische Kartellkonstellationen mangels konspirativer Treffen in den Hintergrund treten. Die Arbeit zeigt auf, unter welchen Voraussetzungen der Einsatz von Preisalgorithmen einen Verstoß gegen das europäische Kartellverbot begründen kann. Dazu werden Fallkonstellationen beleuchtet, die ein algorithmisches Zusammenwirken sowohl unmittelbar zwischen Wettbewerbern als auch mittelbar über einen Dritten begründen. Ferner wird auch auf algorithmenspezifische Compliance-Maßnahmen eingegangen. Schließlich werden die praktischen Herausforderungen bei der Aufdeckung und dem Nachweis solcher Kartelle aufgezeigt.
What does the future hold for corporate communications? The Communications Trend Radar is an applied research project. On an annual basis, it identifies relevant trends for corporate communications from the fields of society, management, and technology. The research team at the University of Potsdam (Professor Stefan Stieglitz, Sünje Clausen, MS.) and Leipzig University (Professor Ansgar Zerfass, Dr Michelle Wloka) identified the following trends for 2024: Information Inflation, AI Literacy, Workforce Shift, Content Integrity, Decoding Humans. More information on the trends can be found in the Communications Trend Radar Report 2024
We would like to inform the readers and editors of the journal that we have discovered some errors in the references of our paper. These errors were brought to our attention by a reader who noticed some inconsistencies between the citations in the text and the bibliography. Upon further investigation, we realized that our literature management software had mistakenly linked some of the references to wrong or non-existent sources. We apologize for this oversight and assure you that it did not affect the validity or quality of our arguments and results, which were based on the correct sources. Below you find a list of the incorrect references along with their corresponding correct ones. We hope that this correction statement will clarify any confusion or misunderstanding that may have arisen from this mistake. The authors would like to apologise for any inconvenience caused.
Online-Nutzer begegnen regelmäßig unterschwelligen manipulativen Designstrategien von Anbietern digitaler Produkte, welche sie zu rechtsgeschäftlich relevanten Entscheidungen bewegen sollen, die sie womöglich nicht - oder zumindest nicht so - beabsichtigt haben. Man spricht in diesem Zusammenhang von (vielgestaltig denkbaren) „Dark Patterns“ (dt. „dunkle Muster“). Der Beitrag geht der Frage nach, inwiefern diese insbesondere lauterkeitsrechtlich zulässig sind.
An die Revolution 1848/49 wird als wesentliches Ereignis deutscher Demokratiegeschichte erinnert; die Beteiligung von Frauen nimmt jedoch bis heute im kollektiven Gedächtnis einen untergeordneten Stellenwert ein. Die vorliegende Masterarbeit beschäftigt sich aus diesem Grund spezifisch mit der Rolle der Frauen in der Revolution 1848/49 und bietet Anregungen für die Integration des Themas in den Politikunterricht.
Wie die Ergebnisse der Arbeit verdeutlichen, nutzten zahlreiche Frauen die Aufbruchsstimmung der 1840er Jahre, um sich auf verschiedene Arten und Weisen politisch zu engagieren. Zwar blieben viele dabei innerhalb der dichotomen Geschlechterteilung verhaftet, welche auf dem sich im 19. Jahrhundert herausbildenden bürgerlichen Geschlechtermodell beruhte. Einige überschritten diese Grenzen jedoch trotz harter Sanktionen auch bewusst.
Sichtbar wird, dass die weibliche Beteiligung zu diesem Zeitpunkt noch nicht zur grundsätzlichen Infragestellung der Geschlechterpolarität führte, aber die Frauen zunehmend den öffentlichen Raum auch für sich beanspruchten und damit die Grundlagen für die deutsche Frauenbewegung der folgenden Jahrzehnte schufen.
Die schulische Thematisierung der Rolle der Frauen in der Revolution 1848/49 bietet sich sowohl im Geschichts- und Politikunterricht als auch fächerübergreifend hinsichtlich vielfältiger Anknüpfungspunkte an. Die Integration des Themas in den Unterricht kann insbesondere dazu beitragen, das historische Erbe der Anfänge der Frauenbewegung zu bewahren, und es zudem für die Vermittlung demokratischer Werte nutzbar machen.
Actin is one of the most highly conserved proteins in eukaryotes and distinct actin-related proteins with filament-forming properties are even found in prokaryotes. Due to these commonalities, actin-modulating proteins of many species share similar structural properties and proposed functions. The polymerization and depolymerization of actin are critical processes for a cell as they can contribute to shape changes to adapt to its environment and to move and distribute nutrients and cellular components within the cell. However, to what extent functions of actin-binding proteins are conserved between distantly related species, has only been addressed in a few cases. In this work, functions of Coronin-A (CorA) and Actin-interacting protein 1 (Aip1), two proteins involved in actin dynamics, were characterized. In addition, the interchangeability and function of Aip1 were investigated in two phylogenetically distant model organisms. The flowering plant Arabidopsis thaliana (encoding two homologs, AIP1-1 and AIP1-2) and in the amoeba Dictyostelium discoideum (encoding one homolog, DdAip1) were chosen because the functions of their actin cytoskeletons may differ in many aspects. Functional analyses between species were conducted for AIP1 homologs as flowering plants do not harbor a CorA gene.
In the first part of the study, the effect of four different mutation methods on the function of Coronin-A protein and the resulting phenotype in D. discoideum was revealed in two genetic knockouts, one RNAi knockdown and a sudden loss-of-function mutant created by chemical-induced dislocation (CID). The advantages and disadvantages of the different mutation methods on the motility, appearance and development of the amoebae were investigated, and the results showed that not all observed properties were affected with the same intensity. Remarkably, a new combination of Selection-Linked Integration and CID could be established.
In the second and third parts of the thesis, the exchange of Aip1 between plant and amoeba was carried out. For A. thaliana, the two homologs (AIP1-1 and AIP1-2) were analyzed for functionality as well as in D. discoideum. In the Aip1-deficient amoeba, rescue with AIP1-1 was more effective than with AIP1-2. The main results in the plant showed that in the aip1-2 mutant background, reintroduced AIP1-2 displayed the most efficient rescue and A. thaliana AIP1-1 rescued better than DdAip1. The choice of the tagging site was important for the function of Aip1 as steric hindrance is a problem. The DdAip1 was less effective when tagged at the C-terminus, while the plant AIP1s showed mixed results depending on the tag position. In conclusion, the foreign proteins partially rescued phenotypes of mutant plants and mutant amoebae, despite the organisms only being very distantly related in evolutionary terms.
Um Mitarbeitende langfristig ans Unternehmen zu binden und das Engagement in Teams hochzuhalten, fokussieren sich viele Maßnahmen zur Verbesserung des Betriebsklimas oder der Zufriedenheit auf die Motivation der Mitarbeitenden. Meist ist es jedoch lohnenswerter, die Zumutungen der organisationalen Struktur zuerst anzufassen. Häufig liegen dort die größten Motivationskiller - und somit auch die Hebel mit dem größten Potenzial für mehr Zufriedenheit.
Optimizing power analysis for randomized experiments: Design parameters for student achievement
(2024)
Randomized trials (RTs) are promising methodological tools to inform evidence-based reform to enhance schooling. Establishing a robust knowledge base on how to promote student achievement requires sensitive RT designs demonstrating sufficient statistical power and precision to draw conclusive and correct inferences on the effectiveness of educational programs and innovations. Proper power analysis is therefore an integral component of any informative RT on student achievement. This venture critically hinges on the availability of reasonable input variance design parameters (and their inherent uncertainties) that optimally reflect the realities around the prospective RT—precisely, its target population and outcome, possibly applied covariates, the concrete design as well as the planned analysis. However, existing compilations in this vein show far-reaching shortcomings.
The overarching endeavor of the present doctoral thesis was to substantively expand available resources devoted to tweak the planning of RTs evaluating educational interventions. At the core of this thesis is a systematic analysis of design parameters for student achievement, generating reliable and versatile compendia and developing thorough guidance to support apt power analysis to design strong RTs. To this end, the thesis at hand bundles two complementary studies which capitalize on rich data of several national probability samples from major German longitudinal large-scale assessments.
Study I applied two- and three-level latent (covariate) modeling to analyze design parameters for a wide spectrum of mathematical-scientific, verbal, and domain-general achievement outcomes. Three vital covariate sets were covered comprising (a) pretests, (b) sociodemographic characteristics, and (c) their combination. The accumulated estimates were additionally summarized in terms of normative distributions.
Study II specified (manifest) single-, two-, and three-level models and referred to influential psychometric heuristics to analyze design parameters and develop concise selection guidelines for covariate (a) types of varying bandwidth-fidelity (domain-identical, cross-domain, fluid intelligence pretests; sociodemographic characteristics), (b) combinations quantifying incremental validities, and (c) time lags of 1- to 7-year-lagged pretests scrutinizing validity degradation. The estimates for various mathematical-scientific and verbal achievement outcomes were meta-analytically integrated and employed in precision simulations.
In doing so, Studies I and II addressed essential gaps identified in previous repertoires in six major dimensions: Taken together, this thesis accumulated novel design parameters and deliberate guidance for RT power analysis (1) tailored to four German student (sub)populations across the entire school career from Grade 1 to 12, (2) matched to 21 achievement (sub)domains, (3) adjusted for 11 covariate sets enriched by empirically supported guidelines, (4) adapted to six RT designs, (5) suitable for latent and manifest analysis models, (6) which were cataloged along with quantifications of their associated uncertainties. These resources are complemented by a plethora of illustrative application examples to gently direct psychological and educational researchers through pivotal steps in the process of RT design.
The striking heterogeneity of the design parameter estimates across all these dimensions constitutes the overall, joint key result of Studies I and II. Hence, this work convincingly reinforces calls for a close match between design parameters and the specific peculiarities of the target RT’s research context.
All in all, the present doctoral thesis offers a—so far unique—nuanced and extensive toolkit to optimize power analysis for sound RTs on student achievement in the German (and similar) school context. It is of utmost importance that research does not tire to spawn robust evidence on what actually works to improve schooling. With this in mind, I hope that the emerging compendia and guidance contribute to the quality and rigor of our randomized experiments in psychology and education.
MARLA
(2024)
Using novel longitudinal data, this paper studies the short- and medium-term effects of Russia's invasion of Ukraine on February 24, 2022 on social trust of adolescents in Germany. Comparing adolescents who responded to our survey shortly before the start of the war with those who responded shortly after the conflict began and applying difference-in-differences (DiD) models over time, we find a significant decline in the outcome after the war started. These findings provide new evidence on how armed conflicts influence social trust and well-being among young people in a country not directly involved in the war.
Heat stress (HS) is a major abiotic stress that negatively affects plant growth and productivity. However, plants have developed various adaptive mechanisms to cope with HS, including the acquisition and maintenance of thermotolerance, which allows them to respond more effectively to subsequent stress episodes. HS memory includes type II transcriptional memory which is characterized by enhanced re-induction of a subset of HS memory genes upon recurrent HS. In this study, new regulators of HS memory in A. thaliana were identified through the characterization of rein mutants.
The rein1 mutant carries a premature stop in CYCLIN-DEPENDENT-KINASE 8 (CDK8) which is part of the cyclin kinase module of the Mediator complex. Rein1 seedlings show impaired type II transcriptional memory in multiple heat-responsive genes upon re-exposure to HS. Additionally, the mutants exhibit a significant deficiency in HS memory at the physiological level. Interaction studies conducted in this work indicate that CDK8 associates with the memory HEAT SHOCK FACTORs HSAF2 and HSFA3. The results suggest that CDK8 plays a crucial role in HS memory in plants together with other memory HSFs, which may be potential targets of the CDK8 kinase function. Understanding the role and interaction network of the Mediator complex during HS-induced transcriptional memory will be an exciting aspect of future HS memory research.
The second characterized mutant, rein2, was selected based on its strongly impaired pAPX2::LUC re-induction phenotype. In gene expression analysis, the mutant revealed additional defects in the initial induction of HS memory genes. Along with this observation, basal thermotolerance was impaired similarly as HS memory at the physiological level in rein2. Sequencing of backcrossed bulk segregants with subsequent fine mapping narrowed the location of REIN2 to a 1 Mb region on chromosome 1. This interval contains the At1g65440 gene, which encodes the histone chaperone SPT6L. SPT6L interacts with chromatin remodelers and bridges them to the transcription machinery to regulate nucleosome and Pol II occupancy around the transcriptional start site. The EMS-induced missense mutation in SPT6L may cause altered HS-induced gene expression in rein2, possibly triggered by changes in the chromatin environment resulting from altered histone chaperone function.
Expanding research on screen-derived factors that modify type II transcriptional memory has the potential to enhance our understanding of HS memory in plants. Discovering connections between previously identified memory factors will help to elucidate the underlying network of HS memory. This knowledge can initiate new approaches to improve heat resilience in crops.
Èto-clefts are Russian focus constructions with the demonstrative pronoun èto ‘this’ at the beginning: “Èto Mark vyigral gonku” (“It was Mark who won the race”). They are often being compared with English it-clefts, German es-clefts, as well as the corresponding focus-background structures in other languages.
In terms of semantics, èto-clefts have two important properties which are cross-linguistically typical for clefts: existence presupposition (“Someone won the race”) and exhaustivity (“Nobody except Mark won the race”). However, the exhaustivity effects are not as strong as exhaustivity effects in structures with the exclusive only and require more research.
At the same time, the question if the syntactic structure of èto-clefts matches the biclausal structure of English and German clefts, remains open. There are arguments in favor of biclausality, as well as monoclausality. Besides, there is no consistency regarding the status of èto itself.
Finally, the information structure of èto-clefts has remained underexplored in the existing literature.
This research investigates the information-structural, syntactic, and semantic properties of Russian clefts, both theoretically (supported by examples from Russian text corpora and judgments from native speakers) and experimentally. It is determined which desired changes in the information structure motivate native speakers to choose an èto-cleft and not the canonical structure or other focus realization tools. Novel syntactic tests are conducted to find evidence for bi-/monoclausality of èto-clefts, as well as for base-generation or movement of the cleft pivot. It is hypothesized that èto has a certain important function in clefts, and its status is investigated. Finally, new experiments on the nature of exhaustivity in èto-clefts are conducted. They allow for direct cross-linguistic comparison, using an incremental-information paradigm with truth-value judgments.
In terms of information structure, this research makes a new proposal that presents èto-clefts as structures with an inherent focus-background bipartitioning. Even though èto-clefts are used in typical focus contexts, evidence was found that èto-clefts (as well as Russian thetic clefts) allow for both new information focus and contrastive focus. Èto-clefts are pragmatically acceptable when a singleton answer to the implied question is expected (e.g. “It was Mark who won the race” but not “It was Mark who came to the party”). Importantly, èto in Russian clefts is neither dummy, nor redundant, but is a topic expression; conveys familiarity which triggers existence presupposition; refers to an instantiated event, or a known/perceivable situation; finally, èto plays an important role in the spoken language as a tool for speech coherency and a focus marker.
In terms of syntax, this research makes a new monoclausal proposal and shows evidence that the cleft pivot undergoes movement to the left peripheral position. Èto is proposed to be TopP.
Finally, in terms of semantics, a novel cross-linguistic evaluation of Russian clefts is made. Experiments show that the exhaustivity inference in èto-clefts is not robust. Participants used different strategies in resolving exhaustivity, falling into 2 groups: one group considered èto-clefts exhaustive, while another group considered them non-exhaustive. Hence, there is evidence for the pragmatic nature of exhaustivity in èto-clefts. The experimental results for èto-clefts are similar to the experimental results for clefts in German, French and Akan. It is concluded that speakers use different tools available in their languages to produce structures with similar interpretive properties.
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.
The origin and structure of magnetic fields in the Galaxy are largely unknown. What is known is that they are essential for several astrophysical processes, in particular the propagation of cosmic rays. Our ability to describe the propagation of cosmic rays through the Galaxy is severely limited by the lack of observational data needed to probe the structure of the Galactic magnetic field on many different length scales. This is particularly true for modelling the propagation of cosmic rays into the Galactic halo, where our knowledge of the magnetic field is particularly poor.
In the last decade, observations of the Galactic halo in different frequency regimes have revealed the existence of out-of-plane bubble emission in the Galactic halo. In gamma rays these bubbles have been termed Fermi bubbles with a radial extent of ≈ 3 kpc and an azimuthal height of ≈ 6 kpc. The radio counterparts of the Fermi bubbles were seen by both the S-PASS telescopes and the Planck satellite, and showed a clear spatial overlap. The X-ray counterparts of the Fermi bubbles were named eROSITA bubbles after the eROSITA satellite, with a radial width of ≈ 7 kpc and an azimuthal height of ≈ 14 kpc. Taken together, these observations suggest the presence of large extended Galactic Halo Bubbles (GHB) and have stimulated interest in exploring the less explored Galactic halo.
In this thesis, a new toy model (GHB model) for the magnetic field and non-thermal electron distribution in the Galactic halo has been proposed. The new toy model has been used to produce polarised synchrotron emission sky maps. Chi-square analysis was used to compare the synthetic skymaps with the Planck 30 GHz polarised skymaps. The obtained constraints on the strength and azimuthal height were found to be in agreement with the S-PASS radio observations.
The upper, lower and best-fit values obtained from the above chi-squared analysis were used to generate three separate toy models. These three models were used to propagate ultra-high energy cosmic rays. This study was carried out for two potential sources, Centaurus A and NGC 253, to produce magnification maps and arrival direction skymaps. The simulated arrival direction skymaps were found to be consistent with the hotspots of Centaurus A and NGC 253 as seen in the observed arrival direction skymaps provided by the Pierre Auger Observatory (PAO).
The turbulent magnetic field component of the GHB model was also used to investigate the extragalactic dipole suppression seen by PAO. UHECRs with an extragalactic dipole were forward-tracked through the turbulent GHB model at different field strengths. The suppression in the dipole due to the varying diffusion coefficient from the simulations was noted. The results could also be compared with an analytical analogy of electrostatics. The simulations of the extragalactic dipole suppression were in agreement with similar studies carried out for galactic cosmic rays.
A comprehensive study on seismic hazard and earthquake triggering is crucial for effective mitigation of earthquake risks. The destructive nature of earthquakes motivates researchers to work on forecasting despite the apparent randomness of the earthquake occurrences. Understanding their underlying mechanisms and patterns is vital, given their potential for widespread devastation and loss of life. This thesis combines methodologies, including Coulomb stress calculations and aftershock analysis, to shed light on earthquake complexities, ultimately enhancing seismic hazard assessment.
The Coulomb failure stress (CFS) criterion is widely used to predict the spatial distributions of aftershocks following large earthquakes. However, uncertainties associated with CFS calculations arise from non-unique slip inversions and unknown fault networks, particularly due to the choice of the assumed aftershocks (receiver) mechanisms. Recent studies have proposed alternative stress quantities and deep neural network approaches as superior to CFS with predefined receiver mechanisms. To challenge these propositions, I utilized 289 slip inversions from the SRCMOD database to calculate more realistic CFS values for a layered-half space and variable receiver mechanisms. The analysis also investigates the impact of magnitude cutoff, grid size variation, and aftershock duration on the ranking of stress metrics using receiver operating characteristic (ROC) analysis. Results reveal the performance of stress metrics significantly improves after accounting for receiver variability and for larger aftershocks and shorter time periods, without altering the relative ranking of the different stress metrics.
To corroborate Coulomb stress calculations with the findings of earthquake source studies in more detail, I studied the source properties of the 2005 Kashmir earthquake and its aftershocks, aiming to unravel the seismotectonics of the NW Himalayan syntaxis. I simultaneously relocated the mainshock and its largest aftershocks using phase data, followed by a comprehensive analysis of Coulomb stress changes on the aftershock planes. By computing the Coulomb failure stress changes on the aftershock faults, I found that all large aftershocks lie in regions of positive stress change, indicating triggering by either co-seismic or post-seismic slip on the mainshock fault.
Finally, I investigated the relationship between mainshock-induced stress changes and associated seismicity parameters, in particular those of the frequency-magnitude (Gutenberg-Richter) distribution and the temporal aftershock decay (Omori-Utsu law). For that purpose, I used my global data set of 127 mainshock-aftershock sequences with the calculated Coulomb Stress (ΔCFS) and the alternative receiver-independent stress metrics in the vicinity of the mainshocks and analyzed the aftershocks properties depend on the stress values. Surprisingly, the results show a clear positive correlation between the Gutenberg-Richter b-value and induced stress, contrary to expectations from laboratory experiments. This observation highlights the significance of structural heterogeneity and strength variations in seismicity patterns. Furthermore, the study demonstrates that aftershock productivity increases nonlinearly with stress, while the Omori-Utsu parameters c and p systematically decrease with increasing stress changes. These partly unexpected findings have significant implications for future estimations of aftershock hazard.
The findings in this thesis provides valuable insights into earthquake triggering mechanisms by examining the relationship between stress changes and aftershock occurrence. The results contribute to improved understanding of earthquake behavior and can aid in the development of more accurate probabilistic-seismic hazard forecasts and risk reduction strategies.
Arachidonsäurelipoxygenasen (ALOX-Isoformen) sind Lipid-peroxidierenden Enzyme, die bei der Zelldifferenzierung und bei der Pathogenese verschiedener Erkrankungen bedeutsam sind. Im menschlichen Genom gibt es sechs funktionelle ALOX-Gene, die als Einzelkopiegene vorliegen. Für jedes humane ALOX-Gen gibt es ein orthologes Mausgen. Obwohl sich die sechs humanen ALOX-Isoformen strukturell sehr ähnlich sind, unterscheiden sich ihre funktionellen Eigenschaften deutlich voneinander. In der vorliegenden Arbeit wurden vier unterschiedliche Fragestellungen zum Vorkommen, zur biologischen Rolle und zur Evolutionsabhängigkeit der enzymatischen Eigenschaften von Säugetier-ALOX-Isoformen untersucht:
1) Spitzhörnchen (Tupaiidae) sind evolutionär näher mit dem Menschen verwandt als Nagetiere und wurden deshalb als Alternativmodelle für die Untersuchung menschlicher Erkrankungen vorgeschlagen. In dieser Arbeit wurde erstmals der Arachidonsäurestoffwechsel von Spitzhörnchen untersucht. Dabei wurde festgestellt, dass im Genom von Tupaia belangeri vier unterschiedliche ALOX15-Gene vorkommen und die Enzyme sich hinsichtlich ihrer katalytischen Eigenschaften ähneln. Diese genomische Vielfalt, die weder beim Menschen noch bei Mäusen vorhanden ist, erschwert die funktionellen Untersuchungen zur biologischen Rolle des ALOX15-Weges. Damit scheint Tupaia belangeri kein geeigneteres Tiermodel für die Untersuchung des ALOX15-Weges des Menschen zu sein.
2) Entsprechend der Evolutionshypothese können Säugetier-ALOX15-Orthologe in Arachidonsäure-12-lipoxygenierende- und Arachidonsäure-15-lipoxygenierende Enzyme eingeteilt werden. Dabei exprimieren Säugetierspezies, die einen höheren Evolutionsgrad als Gibbons aufweisen, Arachidonsäure-15-lipoxygenierende ALOX15-Orthologe, während evolutionär weniger weit entwickelte Säugetiere Arachidonsäure-12 lipoxygenierende Enzyme besitzen. In dieser Arbeit wurden elf neue ALOX15-Orthologe als rekombinante Proteine exprimiert und funktionell charakterisiert. Die erhaltenen Ergebnisse fügen sich widerspruchsfrei in die Evolutionshypothese ein und verbreitern deren experimentelle Basis. Die experimentellen Daten bestätigen auch das Triadenkonzept.
3) Da humane und murine ALOX15B-Orthologe unterschiedliche funktionelle Eigenschaften aufweisen, können Ergebnisse aus murinen Krankheitsmodellen zur biologischen Rolle der ALOX15B nicht direkt auf den Menschen übertragen werden. Um die ALOX15B-Orthologen von Maus und Mensch funktionell einander anzugleichen, wurden im Rahmen der vorliegenden Arbeit Knock-in Mäuse durch die In vivo Mutagenese mittels CRISPR/Cas9-Technik hergestellt. Diese exprimieren eine humanisierte Mutante (Doppelmutation von Tyrosin603Asparaginsäure+Histidin604Valin) der murinen Alox15b. Diese Mäuse waren lebens- und fortpflanzungsfähig, zeigten aber geschlechtsspezifische Unterschiede zu ausgekreuzten Wildtyp-Kontrolltieren im Rahmen ihre Individualentwicklung.
4) In vorhergehenden Untersuchungen zur Rolle der ALOX15B in Rahmen der Entzündungsreaktion wurde eine antiinflammatorische Wirkung des Enzyms postuliert. In der vorliegenden Arbeit wurde untersucht, ob eine Humanisierung der murinen Alox15b die Entzündungsreaktion in zwei verschiedenen murinen Entzündungsmodellen beeinflusst. Eine Humanisierung der murinen Alox15b führte zu einer verstärkten Ausbildung von Entzündungssymptomen im induzierten Dextran-Natrium-Sulfat-Kolitismodell. Im Gegensatz dazu bewirkte die Humanisierung der Alox15b eine Abschwächung der Entzündungssymptome im Freund‘schen Adjuvans Pfotenödemmodell. Diese Daten deuten darauf hin, dass sich die Rolle der ALOX15B in verschiedenen Entzündungsmodellen unterscheidet.
Hässlich aber gut
(2024)
Im Kontext der zunehmenden Relevanz des Umgangs mit Digitalität im schulischen Unterricht und der daraus resultierenden Popularität von Gaming und Gamification als Lehrmethoden ist das Ziel dieser Arbeit, Game Design als konstruktivistische Herangehensweise an Computerspiele zu untersuchen. Genauer geht es darum, diese Methode hinsichtlich der Tauglichkeit für den Kunstunterricht zu analysieren. Dazu wird darauf eingegangen, inwiefern Game Design als Instruktionsmethode generell Lernen fördert bzw. zur Ausbildung einer Digital Literacy geeignet ist. Der Schwerpunkt liegt darin, Game Design im Hinblick auf die zentralen Kompetenz- und Lerndimensionen des Kunstunterrichts zu beleuchten. Genauer sind damit die künstlerische Produktion und die ästhetische Rezeption als die beiden maßgeblichen künstlerisch-ästhetischen Handlungskompetenzen gemeint sowie die ästhetische Erfahrung als besonderes Lernerlebnis, welches im kunstpädagogischen Diskurs neben den beschriebenen Kompetenzen als höchstes Ziel der Lehre gilt. Ebendiese drei Dimensionen funktionieren hierbei als Analyseebenen der untersuchten Methode. Game Design stellt sich dabei als weitestgehend förderlich für alle drei benannten Bereiche heraus, wobei es in Bezug auf die sinnliche Wahrnehmung im Prozess der ästhetischen Rezeption nur eine ergänzende Funktion annimmt. Es werden nicht alle Bereiche der Gestaltungsfelder der künstlerischen Produktion angesprochen. Ein experimentell-offenes künstlerisches Arbeiten wird ebenso nicht zwangsläufig ermöglicht. Jedoch werden alle anderen Bestandteile dieser Kompetenzdimensionen angesprochen und insbesondere die ästhetische Erfahrung vollumfänglich gefördert. Die digitale Spielentwicklung lässt sich somit aus kunstpädagogischer Perspektive für den Einsatz im Kunstunterricht legitimieren. Mit Ausblick auf STEAM Education und einen projektorientierten Unterricht ist sie sogar zu empfehlen.
Die fortschreitende Digitalisierung durchzieht immer mehr Lebensbereiche und führt zu immer komplexeren sozio-technischen Systemen. Obwohl diese Systeme zur Lebenserleichterung entwickelt werden, können auch unerwünschte Nebeneffekte entstehen. Ein solcher Nebeneffekt könnte z.B. die Datennutzung aus Fitness-Apps für nachteilige Versicherungsentscheidungen sein. Diese Nebeneffekte manifestieren sich auf allen Ebenen zwischen Individuum und Gesellschaft. Systeme mit zuvor unerwarteten Nebeneffekten können zu sinkender Akzeptanz oder einem Verlust von Vertrauen führen. Da solche Nebeneffekte oft erst im Gebrauch in Erscheinung treten, bedarf es einer besonderen Betrachtung bereits im Konstruktionsprozess. Mit dieser Arbeit soll ein Beitrag geleistet werden, um den Konstruktionsprozess um ein geeignetes Hilfsmittel zur systematischen Reflexion zu ergänzen.
In vorliegender Arbeit wurde ein Analysetool zur Identifikation und Analyse komplexer Interaktionssituationen in Software-Entwicklungsprojekten entwickelt. Komplexe Interaktionssituationen sind von hoher Dynamik geprägt, aus der eine Unvorhersehbarkeit der Ursache-Wirkungs-Beziehungen folgt. Hierdurch können die Akteur*innen die Auswirkungen der eigenen Handlungen nicht mehr überblicken, sondern lediglich im Nachhinein rekonstruieren. Hieraus können sich fehlerhafte Interaktionsverläufe auf vielfältigen Ebenen ergeben und oben genannte Nebeneffekte entstehen. Das Analysetool unterstützt die Konstrukteur*innen in jeder Phase der Entwicklung durch eine angeleitete Reflexion, um potenziell komplexe Interaktionssituationen zu antizipieren und ihnen durch Analyse der möglichen Ursachen der Komplexitätswahrnehmung zu begegnen.
Ausgehend von der Definition für Interaktionskomplexität wurden Item-Indikatoren zur Erfassung komplexer Interaktionssituationen entwickelt, die dann anhand von geeigneten Kriterien für Komplexität analysiert werden. Das Analysetool ist als „Do-It-Yourself“ Fragebogen mit eigenständiger Auswertung aufgebaut. Die Genese des Fragebogens und die Ergebnisse der durchgeführten Evaluation an fünf Softwarentwickler*innen werden dargestellt. Es konnte festgestellt werden, dass das Analysetool bei den Befragten als anwendbar, effektiv und hilfreich wahrgenommen wurde und damit eine hohe Akzeptanz bei der Zielgruppe genießt. Dieser Befund unterstützt die gute Einbindung des Analysetools in den Software-Entwicklungsprozess.
Additive manufacturing (AM) processes enable the production of metal structures with exceptional design freedom, of which laser powder bed fusion (PBF-LB) is one of the most common. In this process, a laser melts a bed of loose feedstock powder particles layer-by-layer to build a structure with the desired geometry. During fabrication, the repeated melting and rapid, directional solidification create large temperature gradients that generate large thermal stress. This thermal stress can itself lead to cracking or delamination during fabrication. More often, large residual stresses remain in the final part as a footprint of the thermal stress. This residual stress can cause premature distortion or even failure of the part in service. Hence, knowledge of the residual stress field is critical for both process optimization and structural integrity.
Diffraction-based techniques allow the non-destructive characterization of the residual stress fields. However, such methods require a good knowledge of the material of interest, as certain assumptions must be made to accurately determine residual stress. First, the measured lattice plane spacings must be converted to lattice strains with the knowledge of a strain-free material state. Second, the measured lattice strains must be related to the macroscopic stress using Hooke's law, which requires knowledge of the stiffness of the material. Since most crystal structures exhibit anisotropic material behavior, the elastic behavior is specific to each lattice plane of the single crystal. Thus, the use of individual lattice planes in monochromatic diffraction residual stress analysis requires knowledge of the lattice plane-specific elastic properties. In addition, knowledge of the microstructure of the material is required for a reliable assessment of residual stress.
This work presents a toolbox for reliable diffraction-based residual stress analysis. This is presented for a nickel-based superalloy produced by PBF-LB. First, this work reviews the existing literature in the field of residual stress analysis of laser-based AM using diffraction-based techniques. Second, the elastic and plastic anisotropy of the nickel-based superalloy Inconel 718 produced by PBF-LB is studied using in situ energy dispersive synchrotron X-ray and neutron diffraction techniques. These experiments are complemented by ex situ material characterization techniques. These methods establish the relationship between the microstructure and texture of the material and its elastic and plastic anisotropy. Finally, surface, sub-surface, and bulk residual stress are determined using a texture-based approach. Uncertainties of different methods for obtaining stress-free reference values are discussed.
The tensile behavior in the as-built condition is shown to be controlled by texture and cellular sub-grain structure, while in the heat-treated condition the precipitation of strengthening phases and grain morphology dictate the behavior. In fact, the results of this thesis show that the diffraction elastic constants depend on the underlying microstructure, including texture and grain morphology. For columnar microstructures in both as-built and heat-treated conditions, the diffraction elastic constants are best described by the Reuss iso-stress model. Furthermore, the low accumulation of intergranular strains during deformation demonstrates the robustness of using the 311 reflection for the diffraction-based residual stress analysis with columnar textured microstructures. The differences between texture-based and quasi-isotropic approaches for the residual stress analysis are shown to be insignificant in the observed case. However, the analysis of the sub-surface residual stress distributions show, that different scanning strategies result in a change in the orientation of the residual stress tensor. Furthermore, the location of the critical sub-surface tensile residual stress is related to the surface roughness and the microstructure. Finally, recommendations are given for the diffraction-based determination and evaluation of residual stress in textured additively manufactured alloys.
Portal = Welt retten
(2024)
Fragen beantworten, Unbekanntes erklären, Rätsel lösen – und die gewonnenen Erkenntnisse zum Nutzen der Menschheit einsetzen: Das treibt Wissenschaftler*innen auf der ganzen Welt an. Forschung ist keine Geheimwissenschaft, die im stillen Kämmerlein passiert. Sie dient im besten Fall allen. Sie funktioniert voraussetzungsfrei und ergebnisoffen, und gerade deshalb können Forschungsergebnisse notwendige Innovationen, Transformation oder Umdenken fördern und auf diese Weise die Welt verändern. Zum Besseren, so die Hoffnung. Für diese Ausgabe der „Portal“ haben wir Universitätspräsident Prof. Oliver Günther, Ph.D. und die Ökologin Prof. Dr. Damaris Zurell gefragt, ob Wissenschaft die Welt retten kann. Sie sind sich einig: Forschung trägt dazu bei, dass viele Menschen ein lebenswertes und erfülltes Leben führen können. Sie betonen aber auch: Wissenschaft kann das nicht allein erreichen, für echte Veränderungen braucht es Politik, Wirtschaft und Gesellschaft.
Wie wichtig es ist, dass wissenschaftliche Erkenntnisse uns zum Handeln bewegen, davon erzählen auch die vielen anderen Geschichten in diesem Heft. Denn in Potsdam tragen nicht nur Wissenschaftler*innen, sondern auch Studierende und Beschäftigte in Technik und Verwaltung dazu bei, die Universität, ihr Umfeld oder „die Welt da draußen“ Stück für Stück besser zu machen. Jonathan Schorsch zum Beispiel, Professor für Jüdische Religions- und Geistesgeschichte, hat den „Grünen Sabbat“ ins Leben gerufen: einen Tag in der Woche, an dem wir der Erde – und uns selbst – eine kleine Pause gönnen. Der Jurist Andreas Zimmermann berichtet von einem Verfahren vor dem Internationalen Gerichtshof zum Klimawandel, an dem er als Forscher beteiligt ist, und seine Kollegin Dr. Anna von Rebay kämpft als Anwältin für die Rechte des Meeres vor Ausbeutung und Verschmutzung. Der Voltaire-Preisträger Gera Gizaw erzählt von einem Flüchtlingscamp in Kenia aus die Geschichten der Menschen dort und der Medizinethiker Robert Ranisch zeigt, wie die Pflege künftig für noch mehr Wohl sorgen kann. Hochschulangehörige engagieren sich für den Bildungsaufstieg von Menschen aus nicht-akademischen Familien und der Student Tobias Föhl kämpft bei ONE gegen Armut auf der Welt. Mitarbeiter aus der Musikwissenschaft verlängern das Leben von alten Möbeln und Musikinstrumenten, Studierende arbeiten mit Jugendfeuerwehren aus der Region zusammen. Der Better World Award wirft ein Licht auf innovative Ideen, die schnellstmöglich ihren Weg aus der Uni in die Öffentlichkeit finden sollten. Wie wichtig die Kommunikation wissenschaftlicher Erkenntnisse ist, zeigen Julia Wandt und Kristin Küter, die Menschen aus dem Wissenschaftsbetrieb beraten, die Anfeindungen ausgesetzt sind. Denn damit es vorangeht, damit Lösungen für Probleme dieser Welt gefunden werden, darf eines nicht geschehen: dass die Forschung verstummt.
The paper argues that economists’ position-taking in discourses of crises should be understood in the light of economists’ positions in the academic field of economics. This hypothesis is investigated by performing a multiple correspondence analysis (MCA) on a prosopographical data set of 144 French economists who positioned themselves between 2008 and 2021 in controversies over the euro crisis, the French political economic model, and French economics. In these disciplinary controversies, different forms of (post-)national academic capital are used by economists to either initiate change or defend the status quo. These strategies are then interpreted as part of more general power struggles over the basic national or post-national constitution and legitimate governance of economy and society.
Zum dreißigjährigen Bestehen des Kommunalwissenschaftlichen Instituts an der Universität Potsdam vereint dieser Jubiläumsband kurze Aufsätze von ehemaligen und aktuellen Vorstandsmitgliedern, von Ehrenmitgliedern des Vorstands, langjährigen wissenschaftlichen Mitarbeitern des Instituts und aktuellen wissenschaftlichen Kooperationspartnern. Die insgesamt zwölf Beiträge befassen sich mit den Kommunalwissenschaften und der Geschichte des Kommunalwissenschaftlichen Instituts, mit aktuellen kommunalwissenschaftlichen Fragestellungen und wissenschaftlichen Kooperationen des KWI. Der vom KWI-Vorstand herausgegebene Band soll einen breiten Blick auf 30 Jahre Kommunalwissenschaften in Brandenburg und an der Universität Potsdam werfen und einen Ausblick auf zukünftige kommunalwissenschaftliche Forschung geben.
§ 4 Kommunalrecht
(2024)
Climate change fundamentally transforms glaciated high-alpine regions, with well-known cryospheric and hydrological implications, such as accelerating glacier retreat, transiently increased runoff, longer snow-free periods and more frequent and intense summer rainstorms. These changes affect the availability and transport of sediments in high alpine areas by altering the interaction and intensity of different erosion processes and catchment properties.
Gaining insight into the future alterations in suspended sediment transport by high alpine streams is crucial, given its wide-ranging implications, e.g. for flood damage potential, flood hazard in downstream river reaches, hydropower production, riverine ecology and water quality. However, the current understanding of how climate change will impact suspended sediment dynamics in these high alpine regions is limited. For one, this is due to the scarcity of measurement time series that are long enough to e.g. infer trends. On the other hand, it is difficult – if not impossible – to develop process-based models, due to the complexity and multitude of processes involved in high alpine sediment dynamics. Therefore, knowledge has so far been confined to conceptual models (which do not facilitate deriving concrete timings or magnitudes for individual catchments) or qualitative estimates (‘higher export in warmer years’) that may not be able to capture decreases in sediment export. Recently, machine-learning approaches have gained in popularity for modeling sediment dynamics, since their black box nature tailors them to the problem at hand, i.e. relatively well-understood input and output data, linked by very complex processes.
Therefore, the overarching aim of this thesis is to estimate sediment export from the high alpine Ötztal valley in Tyrol, Austria, over decadal timescales in the past and future – i.e. timescales relevant to anthropogenic climate change. This is achieved by informing, extending, evaluating and applying a quantile regression forest (QRF) approach, i.e. a nonparametric, multivariate machine-learning technique based on random forest.
The first study included in this thesis aimed to understand present sediment dynamics, i.e. in the period with available measurements (up to 15 years). To inform the modeling setup for the two subsequent studies, this study identified the most important predictors, areas within the catchments and time periods. To that end, water and sediment yields from three nested gauges in the upper Ötztal, Vent, Sölden and Tumpen (98 to almost 800 km² catchment area, 930 to 3772 m a.s.l.) were analyzed for their distribution in space, their seasonality and spatial differences therein, and the relative importance of short-term events. The findings suggest that the areas situated above 2500 m a.s.l., containing glacier tongues and recently deglaciated areas, play a pivotal role in sediment generation across all sub-catchments. In contrast, precipitation events were relatively unimportant (on average, 21 % of annual sediment yield was associated to precipitation events). Thus, the second and third study focused on the Vent catchment and its sub-catchment above gauge Vernagt (11.4 and 98 km², 1891 to 3772 m a.s.l.), due to their higher share of areas above 2500 m. Additionally, they included discharge, precipitation and air temperature (as well as their antecedent conditions) as predictors.
The second study aimed to estimate sediment export since the 1960s/70s at gauges Vent and Vernagt. This was facilitated by the availability of long records of the predictors, discharge, precipitation and air temperature, and shorter records (four and 15 years) of turbidity-derived sediment concentrations at the two gauges. The third study aimed to estimate future sediment export until 2100, by applying the QRF models developed in the second study to pre-existing precipitation and temperature projections (EURO-CORDEX) and discharge projections (physically-based hydroclimatological and snow model AMUNDSEN) for the three representative concentration pathways RCP2.6, RCP4.5 and RCP8.5.
The combined results of the second and third study show overall increasing sediment export in the past and decreasing export in the future. This suggests that peak sediment is underway or has already passed – unless precipitation changes unfold differently than represented in the projections or changes in the catchment erodibility prevail and override these trends. Despite the overall future decrease, very high sediment export is possible in response to precipitation events. This two-fold development has important implications for managing sediment, flood hazard and riverine ecology.
This thesis shows that QRF can be a very useful tool to model sediment export in high-alpine areas. Several validations in the second study showed good performance of QRF and its superiority to traditional sediment rating curves – especially in periods that contained high sediment export events, which points to its ability to deal with threshold effects. A technical limitation of QRF is the inability to extrapolate beyond the range of values represented in the training data. We assessed the number and severity of such out-of-observation-range (OOOR) days in both studies, which showed that there were few OOOR days in the second study and that uncertainties associated with OOOR days were small before 2070 in the third study. As the pre-processed data and model code have been made publically available, future studies can easily test further approaches or apply QRF to further catchments.
Klausur im Medienrecht
(2024)
Die Privatsphäre prominenter Personen wird häufig durch eine auf Sensationsgier ausgerichtete Presseberichterstattung gefährdet. Während sich die Presse dabei vordergründig auf ein öffentliches Interesse an solchen Berichten beruft, kann die Reputation der Betroffenen in der Öffentlichkeit stark und dauerhaft beeinträchtigt werden. Jedoch folgen aus dem Allgemeinen Persönlichkeitsrecht mehrere Ansprüche, mit denen diese Rechtsverletzungen abgewehrt und mögliche Schäden kompensiert werden können.
§ 70 Hohe See
(2024)
Wir nehmen eine vergleichende Untersuchung der Nominierten und Preisträger:innen von sieben Buchpreisen im deutschsprachigen Raum vor, die mit einer vorab veröffentlichten Long- und/oder Shortlist arbeiten. Dazu vergleichen wir die Preise in Bezug auf soziodemographische Faktoren der Autor:innen (Geschlecht, Alter und Muttersprache), deren Bekanntheit zum Zeitpunkt der Nominierung (Aufrufe auf Wikipedia), die Anzahl vorheriger Nominierungen der Autor:innen für den gleichen Buchpreis, die ›Qualität‹ der ausgezeichneten Bücher (Anzahl der Rezensionen des nominierten Buches, positive bzw. negative Beurteilung in Rezensionen sowie die Einigkeit der Rezensent:innen darüber), das Ansehen der Verlage und die Geschlechterzusammensetzung der Jurys. Der Analysezeitraum umfasst 15 Jahre. Unser Datensatz beinhaltet Informationen zu 428 Autor:innen mit insgesamt 627 zwischen den Jahren 2005 und 2020 nominierten Büchern und 2.469 Rezensionen zu diesen Büchern. Der Datensatz wurde mittels mehrerer Methoden (z. B. Web-Scraping, Hand-Kodierung, Expert:innenbewertungen) aus verschiedenen Quellen (z. B. Web-Daten, Bibliothekskataloge, Expert:innenbewertungen) zusammengestellt. Auf diese Weise können wir unter anderem zeigen, dass für alle untersuchten Preise überwiegend deutsche Muttersprachler:innen mit gut rezensierten Büchern aus renommierten Verlagen nominiert werden und die Preise gewinnen.
Large parts of the Earth’s interior are inaccessible to direct observation, yet global geodynamic processes are governed by the physical material properties under extreme pressure and temperature conditions. It is therefore essential to investigate the deep Earth’s physical properties through in-situ laboratory experiments. With this goal in mind, the optical properties of mantle minerals at high pressure offer a unique way to determine a variety of physical properties, in a straight-forward, reproducible, and time-effective manner, thus providing valuable insights into the physical processes of the deep Earth. This thesis focusses on the system Mg-Fe-O, specifically on the optical properties of periclase (MgO) and its iron-bearing variant ferropericlase ((Mg,Fe)O), forming a major planetary building block. The primary objective is to establish links between physical material properties and optical properties. In particular the spin transition in ferropericlase, the second-most abundant phase of the lower mantle, is known to change the physical material properties. Although the spin transition region likely extends down to the core-mantle boundary, the ef-fects of the mixed-spin state, where both high- and low-spin state are present, remains poorly constrained.
In the studies presented herein, we show how optical properties are linked to physical properties such as electrical conductivity, radiative thermal conductivity and viscosity. We also show how the optical properties reveal changes in the chemical bonding. Furthermore, we unveil how the chemical bonding, the optical and other physical properties are affected by the iron spin transition. We find opposing trends in the pres-sure dependence of the refractive index of MgO and (Mg,Fe)O. From 1 atm to ~140 GPa, the refractive index of MgO decreases by ~2.4% from 1.737 to 1.696 (±0.017). In contrast, the refractive index of (Mg0.87Fe0.13)O (Fp13) and (Mg0.76Fe0.24)O (Fp24) ferropericlase increases with pressure, likely because Fe Fe interactions between adjacent iron sites hinder a strong decrease of polarizability, as it is observed with increasing density in the case of pure MgO. An analysis of the index dispersion in MgO (decreasing by ~23% from 1 atm to ~103 GPa) reflects a widening of the band gap from ~7.4 eV at 1 atm to ~8.5 (±0.6) eV at ~103 GPa. The index dispersion (between 550 and 870 nm) of Fp13 reveals a decrease by a factor of ~3 over the spin transition range (~44–100 GPa). We show that the electrical band gap of ferropericlase significantly widens up to ~4.7 eV in the mixed spin region, equivalent to an increase by a factor of ~1.7. We propose that this is due to a lower electron mobility between adjacent Fe2+ sites of opposite spin, explaining the previously observed low electrical conductivity in the mixed spin region. From the study of absorbance spectra in Fp13, we show an increasing covalency of the Fe-O bond with pressure for high-spin ferropericlase, whereas in the low-spin state a trend to a more ionic nature of the Fe-O bond is observed, indicating a bond weakening effect of the spin transition. We found that the spin transition is ultimately caused by both an increase of the ligand field-splitting energy and a decreasing spin-pairing energy of high-spin Fe2+.
This dissertation examines the lack of clarity in the scientific literature regarding gender and negotiation performance. It is often claimed that men negotiate better than women, yet it is simultaneously emphasized that results strongly depend on context. Through the use of qualitative methods such as content analysis and critical mixed-methods review, the research question: "Are women truly inferior negotiators compared to men?" is addressed. The study comprises a descriptive and an interpretive part. The descriptive section illuminates various interpretations of gender-specific negotiation theory among citing authors, with 67% arguing for a general superiority of men. However, given the high variance in gender-specific differences, the focus should instead be on the context-dependency of negotiation performance. Generalized statements can be made within contexts, but not across them. In the interpretive section, several factors contributing to this misinterpretation are highlighted, including discrepancies in the definition of negotiation performance and distortions in research communication.. From a scientific perspective, this study underscores the need for a nuanced sociological analysis and warns against the one-sided acceptance of inaccurate scientific interpretations. From a practical standpoint, it amplifies the voices of women affected by biased research paradigms. Overall, the dissertation clarifies the theory of gender-specific negotiation performance and advocates for the elimination of biases in scientific discourse.
Wie ist der „gute Ruf“ von Unternehmen und Einzelpersonen im Umfeld von Online-Bewertungsplattformen geschützt? Das Werk erforscht, ob und inwieweit das geltende Recht einen adäquaten und lückenlosen Schutz für die unternehmerische und personelle Reputation gewährleitstet. Die Systematisierung und Untersuchung des bestehenden Regelungsgefüges konzentriert sich auf das Lauterkeitsrecht und das allgemeine Deliktsrecht unter besonderer Berücksichtigung der rechtlichen Innovationen auf nationaler (UWG-Reform 2022) und europäischer (New Deal for Consumers, Digital Services Act) Ebene.
Die Dissertation wurde für den ›Justizpreis Berlin-Brandenburg – Carl Gottlieb Svarez 2024‹ vorgeschlagen.
This study focuses on William Faulkner, whose works explore the demise of the slavery-based Old South during the Civil War in a highly experimental narrative style. Central to this investigation is the analysis of the temporal dimensions of both individual and collective guilt, thus offering a new approach to the often-discussed problem of Faulkner’s portrayal of social decay. The thesis examines how Faulkner re-narrates the legacy of the Old South as a guilt narrative and argues that Faulkner uses guilt in order to corroborate his concept of time and the idea of the continuity of the past. The focus of the analysis is on three of Faulkner’s arguably most important novels: The Sound and the Fury, Absalom, Absalom!, and Go Down, Moses. Each of these novels features a main character deeply overwhelmed by the crimes of the past, whether private, familial, or societal. As a result, guilt is explored both from a domestic as well as a social perspective. In order to show how Faulkner blends past and present by means of guilt, this work examines several methods and motifs borrowed from different fields and genres with which Faulkner narratively negotiates guilt. These include religious notions of original sin, the motif of the ancestral curse prevalent in the Southern Gothic genre, and the psychological concept of trauma. Each of these motifs emphasizes the temporal dimensions of guilt, which are the core of this study, and makes clear that guilt in Faulkner’s work is primarily to be understood as a temporal rather than a moral problem.
Die islamische Speiseordnung
(2024)
The present dissertation investigates changes in lingual coarticulation across childhood in German-speaking children from three to nine years of age and adults. Coarticulation refers to the mismatch between the abstract phonological units and their seemingly commingled realization in continuous speech. Being a process at the intersection of phonology and phonetics, addressing its changes across childhood allows for insights in speech motor as well as phonological developments. Because specific predictions for changes in coarticulation across childhood can be derived from existing speech production models, investigating children’s coarticulatory patterns can help us model human speech production.
While coarticulatory changes may shed light on some of the central questions of speech production development, previous studies on the topic were sparse and presented a puzzling picture of conflicting findings. One of the reasons for this lack is the difficulty in articulatory data acquisition in a young population. Within the research program this dissertation is embedded in, we accepted this challenge and successfully set up the hitherto largest corpus of articulatory data from children using ultrasound tongue imaging. In contrast to earlier studies, a high number of participants in tight age cohorts across a wide age range and a thoroughly controlled set of pseudowords allowed for statistically powerful investigations of a process known as variable and complicated to track.
The specific focus of my studies is on lingual vocalic coarticulation as measured in the horizontal position of the highest point of the tongue dorsum. Based on three studies on a) anticipatory coarticulation towards the left, b) carryover coarticulation towards the right side of the utterance, and c) anticipatory coarticulatory extent in repeated versus read aloud speech, I deduct the following main theses:
1. Maturing speech motor control is responsible for some developmental changes in coarticulation.
2. Coarticulation can be modeled as the coproduction of articulatory gestures.
3. The developmental change in coarticulation results from a decrease of vocalic activation width.
Purpose
The purpose of this study was to investigate work-related adaptive performance from a longitudinal process perspective. This paper clustered specific behavioral patterns following the introduction of a change and related them to retentivity as an individual cognitive ability. In addition, this paper investigated whether the occurrence of adaptation errors varied depending on the type of change content.
Design/methodology/approach
Data from 35 participants collected in the simulated manufacturing environment of a Research and Application Center Industry 4.0 (RACI) were analyzed. The participants were required to learn and train a manufacturing process in the RACI and through an online training program. At a second measurement point in the RACI, specific manufacturing steps were subject to change and participants had to adapt their task execution. Adaptive performance was evaluated by counting the adaptation errors.
Findings
The participants showed one of the following behavioral patterns: (1) no adaptation errors, (2) few adaptation errors, (3) repeated adaptation errors regarding the same actions, or (4) many adaptation errors distributed over many different actions. The latter ones had a very low retentivity compared to the other groups. Most of the adaptation errors were made when new actions were added to the manufacturing process.
Originality/value
Our study adds empirical research on adaptive performance and its underlying processes. It contributes to a detailed understanding of different behaviors in change situations and derives implications for organizational change management.