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Das in diesem Beitrag vorgestellte Projektseminarkonzept reagiert auf eine wahrgenommene Distanz und Unsicherheit Studierender im Fach Lebensgestaltung-Ethik-Religionskunde gegenüber religionsbezogenen Themen. Mittels verschiedener Strategien wurde, ausgehend von der Conceptual Change-Forschung, zur Wahrnehmung und Reflexion des eigenen kulturellen Standortes und der eigenen Konzepte in Bezug auf Religion(en) angeregt. Ihren Lernprozess haben die Studierenden in Arbeitsjournaleinträgen festgehalten. Diese Einträge wurden wiederum mittels einer qualitative Inhaltsanalyse untersucht. Nach der Darstellung der dabei erhobenen religions- und unterrichtsbezogenen Vorstellungen der Studierenden werden im Beitrag Anregungen gegeben, inwiefern die analysierten Befunde als Grundlage für die Verbesserung der Hochschullehre im Fachbereich dienen können.
Der Band präsentiert eine systematische Aufbereitung empirischer Befunde zum Lobbyismus in Deutschland und vermittelt, wie Lobbyist*innen, Entscheidungsträger*innen und institutionelle Rahmen miteinander interagieren. Untersucht werden politische Aktivitäten von sozialen Bewegungen, Verbänden, Unternehmen und Beratungsfirmen im Bundestag, der Bundesregierung und der Öffentlichkeit.
To manage tabular data files and leverage their content in a given downstream task, practitioners often design and execute complex transformation pipelines to prepare them. The complexity of such pipelines stems from different factors, including the nature of the preparation tasks, often exploratory or ad-hoc to specific datasets; the large repertory of tools, algorithms, and frameworks that practitioners need to master; and the volume, variety, and velocity of the files to be prepared. Metadata plays a fundamental role in reducing this complexity: characterizing a file assists end users in the design of data preprocessing pipelines, and furthermore paves the way for suggestion, automation, and optimization of data preparation tasks.
Previous research in the areas of data profiling, data integration, and data cleaning, has focused on extracting and characterizing metadata regarding the content of tabular data files, i.e., about the records and attributes of tables. Content metadata are useful for the latter stages of a preprocessing pipeline, e.g., error correction, duplicate detection, or value normalization, but they require a properly formed tabular input. Therefore, these metadata are not relevant for the early stages of a preparation pipeline, i.e., to correctly parse tables out of files. In this dissertation, we turn our focus to what we call the structure of a tabular data file, i.e., the set of characters within a file that do not represent data values but are required to parse and understand the content of the file. We provide three different approaches to represent file structure, an explicit representation based on context-free grammars; an implicit representation based on file-wise similarity; and a learned representation based on machine learning.
In our first contribution, we use the grammar-based representation to characterize a set of over 3000 real-world csv files and identify multiple structural issues that let files deviate from the csv standard, e.g., by having inconsistent delimiters or containing multiple tables. We leverage our learnings about real-world files and propose Pollock, a benchmark to test how well systems parse csv files that have a non-standard structure, without any previous preparation. We report on our experiments on using Pollock to evaluate the performance of 16 real-world data management systems.
Following, we characterize the structure of files implicitly, by defining a measure of structural similarity for file pairs. We design a novel algorithm to compute this measure, which is based on a graph representation of the files' content. We leverage this algorithm and propose Mondrian, a graphical system to assist users in identifying layout templates in a dataset, classes of files that have the same structure, and therefore can be prepared by applying the same preparation pipeline.
Finally, we introduce MaGRiTTE, a novel architecture that uses self-supervised learning to automatically learn structural representations of files in the form of vectorial embeddings at three different levels: cell level, row level, and file level. We experiment with the application of structural embeddings for several tasks, namely dialect detection, row classification, and data preparation efforts estimation.
Our experimental results show that structural metadata, either identified explicitly on parsing grammars, derived implicitly as file-wise similarity, or learned with the help of machine learning architectures, is fundamental to automate several tasks, to scale up preparation to large quantities of files, and to provide repeatable preparation pipelines.
Social institutions
(2024)
Social institutions are a system of behavioral and relationship patterns that are densely interwoven and enduring and function across an entire society. They order and structure the behavior of individuals in core areas of society and thus have a strong impact on the quality of life of individuals. Institutions regulate the following: (a) family and relationship networks carry out social reproduction and socialization; (b) institutions in the realm of education and training ensure the transmission and cultivation of knowledge, abilities, and specialized skills; (c) institutions in the labor market and economy provide for the production and distribution of goods and services; (d) institutions in the realm of law, governance, and politics provide for the maintenance of the social order; (e) while cultural, media, and religious institutions further the development of contexts of meaning, value orientations, and symbolic codes.
Comparamos la labialización no asimiladora de nasales finales en español en tres corpus de español americano (mexicano, colombiano y paraguayo). Si bien es conocida la labialización no asimiladora en español yucateco, es en gran parte desconocida en otras regiones de habla hispana, por lo que a menudo se atribuye a la influencia maya. Ahora bien, se han señalado casualmente hábitos de pronunciación similares tanto en Paraguay como en Colombia. Comparando empíricamente la labialización en tres corpus constituidos sobre la misma base metodológica, concluimos que la evidencia a favor del contacto lingüístico es como mucho sumamente indirecta. Independientemente de esto, encontramos que la diferencia más marcada es que la tasa de labialización parece ser determinada por la duración de la pausa subsiguiente en los datos de la península yucateca, mas no en aquellos de Colombia y Paraguay. Argumentamos que es cierto que el contacto puede eventualmente haber desencadenado el desarrollo de este rasgo en el español yucateco, puesto que el español actual casi no conoce nasales labiales finales, pero el maya sí. Sin embargo, el perfil lingüístico (hablantes monolingües vs. bilingües) no tiene ningún efecto en nuestros datos yucatecos y paraguayos, y en el total de nuestros datos tampoco encontramos evidencia en favor de la hipótesis que el contacto lingüístico hubiera jugado un rol (importante) en el desarrollo de las labiales nasales en las tres variedades.
Sexualität in der Geschichte
(2024)
Jelena Tomović führt in diesem Band durch die Entwicklungen unserer sexuellen Sprache und Praktiken. Sie zeigt, dass die Art und Weise, wie über Sexualität gesprochen wird, nicht nur ein Spiegelbild, sondern auch ein treibender Faktor für soziale Veränderungen ist. Die Studie stellt die konventionelle Vorstellung von Sexualität in Frage und führt die Lesenden in eine Welt der subtilen Nuancen und kulturellen Veränderungen. Mit kommunikationstheoretischen Ansätzen, dem praxeologischen Ansatz, ihrer sozialkonstruktivistischen Grundannahme und einem klaren Fokus auf Akteur*innen bietet die Autorin eine frische Perspektive auf die Geschichte der Sexualität. Das Buch eröffnet neue Wege für die Erforschung und das Verständnis von Intimität und sozialer Kommunikation.
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.
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.
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.
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.
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.
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.
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.
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.
§ 70 Hohe See
(2024)
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.
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.
Openness indicators for the evaluation of digital platforms between the launch and maturity phase
(2024)
In recent years, the evaluation of digital platforms has become an important focus in the field of information systems science. The identification of influential indicators that drive changes in digital platforms, specifically those related to openness, is still an unresolved issue. This paper addresses the challenge of identifying measurable indicators and characterizing the transition from launch to maturity in digital platforms. It proposes a systematic analytical approach to identify relevant openness indicators for evaluation purposes. The main contributions of this study are the following (1) the development of a comprehensive procedure for analyzing indicators, (2) the categorization of indicators as evaluation metrics within a multidimensional grid-box model, (3) the selection and evaluation of relevant indicators, (4) the identification and assessment of digital platform architectures during the launch-to-maturity transition, and (5) the evaluation of the applicability of the conceptualization and design process for digital platform evaluation.
Die Zusammenarbeit zwischen Lehr- und anderen Fachkräften stellt in Modellen inklusiver Schul- und Unterrichtsentwicklung sowie Schuleffektivität ein wichtiges Element dar. Wenngleich Kooperation als bedeutsam postuliert wird, so belegen Studien, dass diese bisher überwiegend in autonomieerhaltenden Formen praktiziert wird. Als entwicklungsförderlich gelten jedoch v.a. komplexere Formen der Zusammenarbeit. Vor dem Hintergrund inklusiver Bildung und dem Anspruch einer bestmöglichen individuellen Entwicklung der Schüler*innen stellt die Zusammenarbeit von Lehr- und Fachkräften folglich ein sehr bedeutsames Thema dar. Es ist zu hinterfragen, wie sich die Zusammenarbeit zwischen Lehr- und Fachkräften im Primar- wie Sekundarstufenbereich an inklusiven Schulen gestaltet, welche Faktoren diese beeinflussen und welche Relevanz die unterschiedlichen Formen der Zusammenarbeit im Prozess inklusiver Schulentwicklung einnehmen. Bestehende Forschungsdesiderata aufgrei-fend, fokussiert die vorliegende Dissertation auf die realisierte Zusammenarbeit von Lehr- und Fachkräften im Primar- und Sekundarstufenbereich inklusiver Schulen, am Beispiel des Landes Brandenburg. Neben den realisierten Formen der Zusammenarbeit, stehen insbesondere die Identifikation von Kooperationsmustern von Lehr- und Fachkräften sowie von Schulen, und deren Zusammenhänge mit der Leistungsentwicklung von Schüler*innen im Kern des Forschungsinteresses.
Die vorliegende Dissertation bearbeitet insgesamt sechs Forschungsfragen, welche in drei Teilstudien adressiert werden: Zunächst werden mittels deskriptiver Analysen sowie Mehrebenenmodellierungen die Ausgangslage multiprofessioneller Kooperation (erste Forschungsfrage) sowie deren Rahmenbedingungen (zweite Forschungsfrage) im Primar- wie Sekundarstufenbereich erfasst (Teilstudie 1). Lehr- und Fachkräfte kooperierten überwiegend in autonomieerhaltenden, austauschbasierten Formen. Weiterhin zeigte sich, dass insbesondere die individuelle Offenheit zur Zusammenarbeit sowie die subjektiv wahrgenommene Unterstützung durch die Schulleitung bedeutsame Faktoren für die Realisierung multiprofessioneller Kooperation darstellten. Die Fragestellungen drei und vier befassen sich mit der Identifikation von Mustern im Kooperationsverhalten (Teilstudie 2). Zum einen geht es hierbei um personenbezogene Profile von Lehr- und Fachkräften (dritte Forschungsfrage), zum anderen um schulbezogene Profile (vierte Forschungsfrage), welche mittels des personenzentrierten Ansatzes der latenten Profilanalysen unter Berücksichtigung der Mehrebenenstruktur identifiziert werden. Hinsichtlich des individuellen Kooperationsverhaltens konnten vier Profile eruiert werden, bzgl. des schulspezifischen Kooperationsverhaltens drei. Die Mehrheit der Lehr- und Fachkräfte konnte im „regularly“-Profil verortet werden, d.h. nach eigener Einschätzung kooperierten diese überdurchschnittlich häufig im Austausch miteinander und arbeitsteilig, aber auch regelmäßig kokonstruktiv. Auf Schulebene zeigte sich, dass etwa jede zweite inklusive Schule im Land Brandenburg über eine hoch ausgeprägte Kooperationskultur verfügte. Im Fokus der Teilstudie 3 wird den Fragen nachgegangen, in welchem Zusammenhang die schulspezifischen Kooperationskulturen mit der Leistungsentwicklung von Schüler*innen in der Primar- wie Sekundarstufe steht. Mittels autoregressiver Mehrebenenanalysen wird einerseits der Zusammenhang mit der Leistungsentwicklung aller Schüler*innen (fünfte Forschungsfrage) untersucht, sowie spezifisch auf die Entwicklung von Schüler*innen mit und ohne sonderpädagogischem Förderbedarf (sechste Forschungsfrage) fokussiert. Ein zentrales Ergebnis war hierbei, dass Schüler*innen mit sonderpädagogischem Förderbedarf in der Primar- wie Sekundarstufe in ihrer Leistungsentwicklung am stärksten profitierten, wenn sie an Schulen lernten, an denen sich die Lehr- und Fachkräfte sehr regelmäßig über Lernstände der Schüler*innen austauschten (Austausch), Arbeitspakete für differenzierte Lernangebote erarbeiteten und verteilten (Arbeitsteilung) und darüber hinaus gelegentlich gemeinsam Problemlösungen entwickelten (Kokonstruktion).
Die Ergebnisse werden vor dem Hintergrund der postulierten Relevanz multiprofessioneller Kooperation für inklusive Schul- und Unterrichtsentwicklungsprozesse eingeordnet und diskutiert. Weiterhin werden verschiedene praktische Implikationen für die Unterstützung multiprofessioneller Zusammenarbeit im Primar- und Sekundarstufenbereich abgeleitet.
The planetary commons
(2024)
The Anthropocene signifies the start of a no- analogue trajectory of the Earth system that is fundamentally different from the Holocene. This new trajectory is characterized by rising risks of triggering irreversible and unmanageable shifts in Earth system functioning. We urgently need a new global approach to safeguard critical Earth system regulating functions more effectively and comprehensively. The global commons framework is the closest example of an existing approach with the aim of governing biophysical systems on Earth upon which the world collectively depends. Derived during stable Holocene conditions, the global commons framework must now evolve in the light of new Anthropocene dynamics. This requires a fundamental shift from a focus only on governing shared resources beyond national jurisdiction, to one that secures critical functions of the Earth system irrespective of national boundaries. We propose a new framework—the planetary commons—which differs from the global commons framework by including not only globally shared geographic regions but also critical biophysical systems that regulate the resilience and state, and therefore livability, on Earth. The new planetary commons should articulate and create comprehensive stewardship obligations through Earth system governance aimed at restoring and strengthening planetary resilience and justice.
Aging is associated with bone loss, which can lead to osteoporosis and high fracture risk. This coincides with the enhanced formation of bone marrow adipose tissue (BMAT), suggesting a negative effect of bone marrow adipocytes on skeletal health. Increased BMAT formation is also observed in pathologies such as obesity, type 2 diabetes and osteoporosis. However, a subset of bone marrow adipocytes forming the constitutive BMAT (cBMAT), arise early in life in the distal skeleton, contain high levels of unsaturated fatty acids and are thought to provide a physiological function. Regulated BMAT (rBMAT) forms during aging and obesity in proximal regions of the bone and contain a large proportion of saturated fatty acids. Paradoxically, BMAT accumulation is also enhanced during caloric restriction (CR), a life-span extending dietary intervention. This indicates, that different types of BMAT can form in response to opposing nutritional stimuli with potentially different functions.
To this end, two types of nutritional interventions, CR and high fat diet (HFD), that are both described to induce BMAT accumulation were carried out. CR markedly increased BMAT formation in the proximal tibia and led to a higher proportion of unsaturated fatty acids, making it similar to the physiological cBMAT. Additionally, proximal and diaphyseal tibia regions displayed higher adiponectin expression. In aged mice, CR was associated with an improved trabecular bone structure. Taken together, these findings demonstrate, that the type of BMAT that forms during CR might provide beneficial effects for local bone stem/progenitor cells and metabolic health. The HFD intervention performed in this thesis showed no effect on BMAT accumulation and bone microstructure. RNA Seq analysis revealed alterations in the composition of the collagen-containing extracellular matrix (ECM).
In order to investigate the effects of glucose homeostasis on osteogenesis, differentiation capacity of immortalized multipotent mesenchymal stromal cells (MSCs) and osteochondrogenic progenitor cells (OPCs) was analyzed. Insulin improved differentiation in both cell types, however, combination of with a high glucose concentration led to an impaired mineralization of the ECM. In the MSCs, this was accompanied by the formation of adipocytes, indicating negative effects of the adipocytes formed during hyperglycemic conditions on mineralization processes. However, the altered mineralization pattern and structure of the ECM was also observed in OPCs, which did not form any adipocytes, suggesting further negative effects of a hyperglycemic environment on osteogenic differentiation.
In summary, the work provided in this thesis demonstrated that differentiation commitment of bone-resident stem cells can be altered through nutrient availability, specifically glucose. Surprisingly, both high nutrient supply, e.g. the hyperglycemic cell culture conditions, and low nutrient supply, e.g. CR, can induce adipogenic differentiation. However, while CR-induced adipocyte formation was associated with improved trabecular bone structure, adipocyte formation in a hyperglycemic cell-culture environment hampered mineralization. This thesis provides further evidence for the existence of different types of BMAT with specific functions.
The wide distribution of location-acquisition technologies means that large volumes of spatio-temporal data are continuously being accumulated. Positioning systems such as GPS enable the tracking of various moving objects' trajectories, which are usually represented by a chronologically ordered sequence of observed locations. The analysis of movement patterns based on detailed positional information creates opportunities for applications that can improve business decisions and processes in a broad spectrum of industries (e.g., transportation, traffic control, or medicine). Due to the large data volumes generated in these applications, the cost-efficient storage of spatio-temporal data is desirable, especially when in-memory database systems are used to achieve interactive performance requirements.
To efficiently utilize the available DRAM capacities, modern database systems support various tuning possibilities to reduce the memory footprint (e.g., data compression) or increase performance (e.g., additional indexes structures). By considering horizontal data partitioning, we can independently apply different tuning options on a fine-grained level. However, the selection of cost and performance-balancing configurations is challenging, due to the vast number of possible setups consisting of mutually dependent individual decisions.
In this thesis, we introduce multiple approaches to improve spatio-temporal data management by automatically optimizing diverse tuning options for the application-specific access patterns and data characteristics. Our contributions are as follows:
(1) We introduce a novel approach to determine fine-grained table configurations for spatio-temporal workloads. Our linear programming (LP) approach jointly optimizes the (i) data compression, (ii) ordering, (iii) indexing, and (iv) tiering. We propose different models which address cost dependencies at different levels of accuracy to compute optimized tuning configurations for a given workload, memory budgets, and data characteristics. To yield maintainable and robust configurations, we further extend our LP-based approach to incorporate reconfiguration costs as well as optimizations for multiple potential workload scenarios.
(2) To optimize the storage layout of timestamps in columnar databases, we present a heuristic approach for the workload-driven combined selection of a data layout and compression scheme. By considering attribute decomposition strategies, we are able to apply application-specific optimizations that reduce the memory footprint and improve performance.
(3) We introduce an approach that leverages past trajectory data to improve the dispatch processes of transportation network companies. Based on location probabilities, we developed risk-averse dispatch strategies that reduce critical delays.
(4) Finally, we used the use case of a transportation network company to evaluate our database optimizations on a real-world dataset. We demonstrate that workload-driven fine-grained optimizations allow us to reduce the memory footprint (up to 71% by equal performance) or increase the performance (up to 90% by equal memory size) compared to established rule-based heuristics.
Individually, our contributions provide novel approaches to the current challenges in spatio-temporal data mining and database research. Combining them allows in-memory databases to store and process spatio-temporal data more cost-efficiently.
Die umfangreiche rechtswissenschaftliche Studie befasst sich mit den preußischen Staatskirchenverträgen aus der Zeit der Weimarer Republik. Diese Verträge waren Höhepunkte einer Entwicklung in Richtung größerer Freiheit und Unabhängigkeit der Kirchen vom Staat, die den Vorgängen im Reich und in anderen deutschen Ländern teils entsprach, teils zuwiderlief. Die Entwicklung folgte keiner unverrückbaren Idealvorstellung über das Verhältnis von Staat und Kirche, sondern stellte sich stets als pragmatische Reaktion auf realpolitische Probleme dar. Die Staatskirchenverträge selbst prägten die weiteren Entwicklungen in Ost und West bis zur Gegenwart.
In Time and the Other Johannes Fabian analysed how modern conceptions of time were “not only secularized and naturalized but also thoroughly spatialized.” According to Fabian, this was particularly visible in modern anthropology which “promoted a scheme in terms of which not only past cultures but all living societies were irrevocably placed on a temporal slope, a stream of Time – some upstream, others downstream.”3 Anthropologists attributed otherness to a distant past which was traditionally associated with cultural retardation, i.e. a lower degree of development, progress, and civilization. Cultural difference was expressed in terms of temporal distance while temporal distance was attributed to spatial remoteness. The result was a phenomenon that Fabian coined “the denial of coevalness” which pointed towards “a persistent and systematic tendency to place the referent(s) of anthropology in a Time other than the present of the producer of anthropological discourse.
The evaluation of process-oriented cognitive theories through time-ordered observations is crucial for the advancement of cognitive science. The findings presented herein integrate insights from research on eye-movement control and sentence comprehension during reading, addressing challenges in modeling time-ordered data, statistical inference, and interindividual variability. Using kernel density estimation and a pseudo-marginal likelihood for fixation durations and locations, a likelihood implementation of the SWIFT model of eye-movement control during reading (Engbert et al., Psychological Review, 112, 2005, pp. 777–813) is proposed. Within the broader framework of data assimilation, Bayesian parameter inference with adaptive Markov Chain Monte Carlo techniques is facilitated for reliable model fitting. Across the different studies, this framework has shown to enable reliable parameter recovery from simulated data and prediction of experimental summary statistics. Despite its complexity, SWIFT can be fitted within a principled Bayesian workflow, capturing interindividual differences and modeling experimental effects on reading across different geometrical alterations of text. Based on these advancements, the integrated dynamical model SEAM is proposed, which combines eye-movement control, a traditionally psychological research area, and post-lexical language processing in the form of cue-based memory retrieval (Lewis & Vasishth, Cognitive Science, 29, 2005, pp. 375–419), typically the purview of psycholinguistics. This proof-of-concept integration marks a significant step forward in natural language comprehension during reading and suggests that the presented methodology can be useful to develop complex cognitive dynamical models that integrate processes at levels of perception, higher cognition, and (oculo-)motor control. These findings collectively advance process-oriented cognitive modeling and highlight the importance of Bayesian inference, individual differences, and interdisciplinary integration for a holistic understanding of reading processes. Implications for theory and methodology, including proposals for model comparison and hierarchical parameter inference, are briefly discussed.
Der tänzerische Kreativitätstest stellt ein valides Instrumentarium dar, welches auf tanzspezifischen Aufgaben basiert und für die differenzierte und standardisierte Erfassung der tänzerischen Kreativität bei Kindern im Alter von 8 bis 12 Jahren konzipiert ist. Mit dem tänzerischen Kreativitätstest können nicht nur Fragestellungen zum Stand sowie zur Entwicklung tänzerisch-kreativer Fähigkeiten im Kindesalter bearbeitet werden, sondern er liefert auch wertvolle Informationen für die Optimierung von Trainings-, Förder- und Vermittlungsmaßnahmen. Erfasst werden folgende tänzerisch-kreativen Fähigkeiten: 1) Vielfalt und Originalität in der Fortbewegung und in Körperpositionen sowie 2) Ideenreichtum, Vielfalt und Originalität in der Gestaltung von Bewegungspatterns und -kompositionen. Dieser Test lässt sich mit größeren Gruppen und minimalem materiellen Aufwand durchführen, ist zeitlich unbeschränkt und ermöglicht es, unterschiedliche Leistungsniveaus zu identifizieren. Der tänzerische Kreativitätstest bietet Forschenden und Lehrkräften eine wertvolle Möglichkeit, die tänzerisch-kreativen Fähigkeiten von Kindern zu analysieren und zu fördern.
Ecosystems play a pivotal role in addressing climate change but are also highly susceptible to drastic environmental changes. Investigating their historical dynamics can enhance our understanding of how they might respond to unprecedented future environmental shifts. With Arctic lakes currently under substantial pressure from climate change, lessons from the past can guide our understanding of potential disruptions to these lakes. However, individual lake systems are multifaceted and complex. Traditional isolated lake studies often fail to provide a global perspective because localized nuances—like individual lake parameters, catchment areas, and lake histories—can overshadow broader conclusions. In light of these complexities, a more nuanced approach is essential to analyze lake systems in a global context.
A key to addressing this challenge lies in the data-driven analysis of sedimentological records from various northern lake systems. This dissertation emphasizes lake systems in the northern Eurasian region, particularly in Russia (n=59). For this doctoral thesis, we collected sedimentological data from various sources, which required a standardized framework for further analysis. Therefore, we designed a conceptual model for integrating and standardizing heterogeneous multi-proxy data into a relational database management system (PostgreSQL). Creating a database from the collected data enabled comparative numerical analyses between spatially separated lakes as well as between different proxies.
When analyzing numerous lakes, establishing a common frame of reference was crucial. We achieved this by converting proxy values from depth dependency to age dependency. This required consistent age calculations across all lakes and proxies using one age-depth modeling software. Recognizing the broader implications and potential pitfalls of this, we developed the LANDO approach ("Linked Age and Depth Modelling"). LANDO is an innovative integration of multiple age-depth modeling software into a singular, cohesive platform (Jupyter Notebook). Beyond its ability to aggregate data from five renowned age-depth modeling software, LANDO uniquely empowers users to filter out implausible model outcomes using robust geoscientific data. Our method is not only novel but also significantly enhances the accuracy and reliability of lake analyses.
Considering the preceding steps, this doctoral thesis further examines the relationship between carbon in sediments and temperature over the last 21,000 years. Initially, we hypothesized a positive correlation between carbon accumulation in lakes and modelled paleotemperature. Our homogenized dataset from heterogeneous lakes confirmed this association, even if the highest temperatures throughout our observation period do not correlate with the highest carbon values. We assume that rapid warming events contribute more to high accumulation, while sustained warming leads to carbon outgassing. Considering the current high concentration of carbon in the atmosphere and rising temperatures, ongoing climate change could cause northern lake systems to contribute to a further increase in atmospheric carbon (positive feedback loop). While our findings underscore the reliability of both our standardized data and the LANDO method, expanding our dataset might offer even greater assurance in our conclusions.
Kants Recht der Freiheit
(2024)
Das vorliegende Buch berücksichtigt neben den drei Kritiken und der späten Rechtslehre Kants Grundlegung zur Metaphysik der Sitten, seine Anthropologie in pragmatischer Hinsicht, den Weltbürgeressay, den Streit der Fakultäten, die Friedensschrift und die Abhandlung über den Gemeinspruch, aus der die Formulierung ‚Recht der Freiheit‘ stammt.
Erstes Kant-Buch zu seiner eigenen Wortschöpfung "Recht der Freiheit".
Erörtert Kants "Rechtslehre und Gerichtsbarkeit" in der Kritik der reinen Vernunft
Mindful Eating
(2024)
Maladaptive eating behaviors such as emotional eating, external eating, and loss-of-control eating are widespread in the general population. Moreover, they are associated to adverse health outcomes and well-known for their role in the development and maintenance of eating disorders and obesity (i.e., eating and weight disorders). Eating and weight disorders are associated with crucial burden for individuals as well as high costs for society in general. At the same time, corresponding treatments yield poor outcomes. Thus, innovative concepts are needed to improve prevention and treatment of these conditions.
The Buddhist concept of mindfulness (i.e., paying attention to the present moment without judgement) and its delivery via mindfulness-based intervention programs (MBPs) has gained wide popularity in the area of maladaptive eating behaviors and associated eating and weight disorders over the last two decades. Though previous findings on their effects seem promising, the current assessment of mindfulness and its mere application via multi-component MBPs hampers to draw conclusions on the extent to which mindfulness-immanent qualities actually account for the effects (e.g., the modification of maladaptive eating behaviors). However, this knowledge is pivotal for interpreting previous effects correctly and for avoiding to cause harm in particularly vulnerable groups such as those with eating and weight disorders.
To address these shortcomings, recent research has focused on the context-specific approach of mindful eating (ME) to investigate underlying mechanisms of action. ME can be considered a subdomain of generic mindfulness describing it specifically in relation to the process of eating and associated feelings, thoughts, and motives, thus including a variety of different attitudes and behaviors. However, there is no universal operationalization and the current assessment of ME suffers from different limitations. Specifically, current measurement instruments are not suited for a comprehensive assessment of the multiple facets of the construct that are currently discussed as important in the literature. This in turn hampers comparisons of different ME facets which would allow to evaluate their particular effect on maladaptive eating behaviors. This knowledge is needed to tailor prevention and treatment of associated eating and weight disorders properly and to explore potential underlying mechanisms of action which have so far been proposed mainly on theoretical grounds.
The dissertation at hand aims to provide evidence-based fundamental research that contributes to our understanding of how mindfulness, more specifically its context-specific form of ME, impacts maladaptive eating behaviors and, consequently, how it could be used appropriately to enrich the current prevention and treatment approaches for eating and weight disorders in the future.
Specifically, in this thesis, three scientific manuscripts applying several qualitative and quantitative techniques in four sequential studies are presented. These manuscripts were published in or submitted to three scientific peer-reviewed journals to shed light on the following questions:
I. How can ME be measured comprehensively and in a reliable and valid way to advance the understanding of how mindfulness works in the context of eating?
II. Does the context-specific construct of ME have an advantage over the generic concept in advancing the understanding of how mindfulness is related to maladaptive eating behaviors?
III. Which ME facets are particularly useful in explaining maladaptive eating behaviors?
IV. Does training a particular ME facet result in changes in maladaptive eating behaviors?
To answer the first research question (Paper 1), a multi-method approach using three subsequent studies was applied to develop and validate a comprehensive self-report instrument to assess the multidimensional construct of ME - the Mindful Eating Inventory (MEI). Study 1 aimed to create an initial version of the MEI by following a three-step approach: First, a comprehensive item pool was compiled by including selected and adapted items of the existing ME questionnaires and supplementing them with items derived from an extensive literature review. Second, the preliminary item pool was complemented and checked for content validity by experts in the field of eating behavior and/or mindfulness (N = 15). Third, the item pool was further refined through qualitative methods: Three focus groups comprising laypersons (N = 16) were used as a check for applicability. Subsequently, think-aloud protocols (N = 10) served as a last check of comprehensibility and elimination of ambiguities.
The resulting initial MEI version was tested in Study 2 in an online convenience sample (N = 828) to explore its factor structure using exploratory factor analysis (EFA). Results were used to shorten the questionnaire in accordance with qualitative and quantitative criteria yielding the final MEI version which encompasses 30 items. These items were assigned to seven ME facets: (1) ‘Accepting and Non-attached Attitude towards one’s own eating experience’ (ANA), (2) ‘Awareness of Senses while Eating’ (ASE), (3) ‘Eating in Response to awareness of Fullness‘ (ERF), (4) ‘Awareness of eating Triggers and Motives’ (ATM), (5) ‘Interconnectedness’ (CON), (6) ‘Non-Reactive Stance’ (NRS) and (7) Focused Attention on Eating’ (FAE).
Study 3 sought to confirm the found facets and the corresponding factor structure in an independent online convenience sample (N = 612) using confirmatory factor analysis (CFA). The study served as further indication of the assumed multidimensionality of ME (the correlational seven-factor model was shown to be superior to a single-factor model). Psychometric properties of the MEI, regarding factorial validity, internal consistency, retest-reliability, and observed criterion validity using a wide range of eating-specific and general health-related outcomes, showed the inventory to be suitable for a comprehensive, reliable and valid assessment of ME. These findings were complemented by demonstrating measurement invariance of the MEI regarding gender. In accordance with the factor structure of the MEI, Paper 1 offers an empirically-derived definition of ME, succeeding in overcoming ambiguities and problems of previous attempts at defining the construct.
To answer the second and third research questions (Paper 2) a subsample of Study 2 from the MEI validation studies (N = 292) was analyzed. Incremental validity of ME beyond generic mindfulness was shown using hierarchical regression models concerning the outcome variables of maladaptive eating behaviors (emotional eating and uncontrolled eating) and nutrition behaviors (consumption of energy-dense food). Multiple regression analyses were applied to investigate the impact of the seven different ME facets (identified in Paper 1) on the same outcome variables. The following ME facets significantly contributed to explaining variance in maladaptive eating and nutrition behaviors: Accepting and Non-attached Attitude towards one`s own eating experience (ANA), Eating in Response to awareness of Fullness (ERF), the Awareness of eating Triggers and Motives (ATM), and a Non-Reactive Stance (NRS, i.e., an observing, non-impulsive attitude towards eating triggers). Results suggest that these ME facets are promising variables to consider when a) investigating potential underlying mechanisms of mindfulness and MBPs in the context of eating and b) addressing maladaptive eating behaviors in general as well as in the prevention and treatment of eating and weight disorders.
To answer the fourth research question (Paper 3), a training on an isolated exercise (‘9 Hunger’) based on the previously identified ME facet ATM was designed to explore its particular association with changes in maladaptive eating behaviors and thus to preliminary explore one possible mechanism of action. The online study was realized using a randomized controlled trial (RCT) design. Latent Change Scores (LCS) across three measurement points (before the training, directly after the training and three months later) were compared between the intervention group (n = 211) and a waitlist control group (n = 188). Short- and longer-term effects of the training could be shown on maladaptive eating behaviors (emotional eating, external eating, loss-of-control eating) and associated outcomes (intuitive eating, ME, self-compassion, well-being). Findings serve as preliminary empirical evidence that MBPs might influence maladaptive eating behaviors through an enhanced non-judgmental awareness of and distinguishment between eating motives and triggers (i.e., ATM). This mechanism of action had previously only been hypothesized from a theoretical perspective. Since maladaptive eating behaviors are associated with eating and weight disorders, the findings can enhance our understanding of the general effects of MBPs on these conditions.
The integration of the different findings leads to several suggestions of how ME might enrich different kinds of future interventions on maladaptive eating behaviors to improve health in general or the prevention and treatment of eating and weight disorders in particular. Strengths of the thesis (e.g., deliberate specific methodology, variety of designs and methods, high number of participants) are emphasized. The main limitations particularly regarding sample characteristics (e.g., higher level of formal education, fewer males, self-selected) are discussed to arrive at an outline for future studies (e.g., including multi-modal-multi-method approaches, clinical eating disorder samples and youth samples) to improve upcoming research on ME and underlying mechanisms of action of MBPs for maladaptive eating behaviors and associated eating and weight disorders.
This thesis enriches current research on mindfulness in the context of eating by providing fundamental research on the core of the ME construct. Thereby it delivers a reliable and valid instrument to comprehensively assess ME in future studies as well as an operational definition of the construct. Findings on ME facet level might inform upcoming research and practice on how to address maladaptive eating behaviors appropriately in interventions. The ME skill ‘Awareness of eating Triggers and Motives (ATM)’ as one particular mechanism of action should be further investigated in representative community and specific clinical samples to examine the validity of the results in these groups and to justify an application of the concept to the general population as well as to subgroups with eating and weight disorders in particular.
In conclusion, findings of the current thesis can be used to set future research on mindfulness, more specifically ME, and its underlying mechanism in the context of eating on a more evidence-based footing. This knowledge can inform upcoming prevention and treatment to tailor MBPs on maladaptive eating behaviors and associated eating and weight disorders appropriately.
Enhancing economic efficiency in modular production systems through deep reinforcement learning
(2024)
In times of increasingly complex production processes and volatile customer demands, the production adaptability is crucial for a company's profitability and competitiveness. The ability to cope with rapidly changing customer requirements and unexpected internal and external events guarantees robust and efficient production processes, requiring a dedicated control concept at the shop floor level. Yet in today's practice, conventional control approaches remain in use, which may not keep up with the dynamic behaviour due to their scenario-specific and rigid properties. To address this challenge, deep learning methods were increasingly deployed due to their optimization and scalability properties. However, these approaches were often tested in specific operational applications and focused on technical performance indicators such as order tardiness or total throughput. In this paper, we propose a deep reinforcement learning based production control to optimize combined techno-financial performance measures. Based on pre-defined manufacturing modules that are supplied and operated by multiple agents, positive effects were observed in terms of increased revenue and reduced penalties due to lower throughput times and fewer delayed products. The combined modular and multi-staged approach as well as the distributed decision-making further leverage scalability and transferability to other scenarios.
Volatile supply and sales markets, coupled with increasing product individualization and complex production processes, present significant challenges for manufacturing companies. These must navigate and adapt to ever-shifting external and internal factors while ensuring robustness against process variabilities and unforeseen events. This has a pronounced impact on production control, which serves as the operational intersection between production planning and the shop- floor resources, and necessitates the capability to manage intricate process interdependencies effectively. Considering the increasing dynamics and product diversification, alongside the need to maintain constant production performances, the implementation of innovative control strategies becomes crucial.
In recent years, the integration of Industry 4.0 technologies and machine learning methods has gained prominence in addressing emerging challenges in production applications. Within this context, this cumulative thesis analyzes deep learning based production systems based on five publications. Particular attention is paid to the applications of deep reinforcement learning, aiming to explore its potential in dynamic control contexts. Analysis reveal that deep reinforcement learning excels in various applications, especially in dynamic production control tasks. Its efficacy can be attributed to its interactive learning and real-time operational model. However, despite its evident utility, there are notable structural, organizational, and algorithmic gaps in the prevailing research. A predominant portion of deep reinforcement learning based approaches is limited to specific job shop scenarios and often overlooks the potential synergies in combined resources. Furthermore, it highlights the rare implementation of multi-agent systems and semi-heterarchical systems in practical settings. A notable gap remains in the integration of deep reinforcement learning into a hyper-heuristic.
To bridge these research gaps, this thesis introduces a deep reinforcement learning based hyper- heuristic for the control of modular production systems, developed in accordance with the design science research methodology. Implemented within a semi-heterarchical multi-agent framework, this approach achieves a threefold reduction in control and optimisation complexity while ensuring high scalability, adaptability, and robustness of the system. In comparative benchmarks, this control methodology outperforms rule-based heuristics, reducing throughput times and tardiness, and effectively incorporates customer and order-centric metrics. The control artifact facilitates a rapid scenario generation, motivating for further research efforts and bridging the gap to real-world applications. The overarching goal is to foster a synergy between theoretical insights and practical solutions, thereby enriching scientific discourse and addressing current industrial challenges.