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Rückkehrbestrebungen und der Lebensverlauf von Geflüchteten in Deutschland
No full textDieser Studienreport kontextualisiert den Datensatz mit 20 biografisch-narrativen Interviews, die im Rahmen des Projekts „Rückkehrbestrebungen und der Lebensverlauf von Geflüchteten in Deutschland“ vom Deutschen Zentrum für Integrations- und Migrationsforschung (DeZIM) durchgeführt wurden. Die Interviews fanden zwischen Mitte 2023 und Anfang 2024 in Berlin statt und wurden in Farsi/Dari, Tigrinya, Englisch oder Deutsch geführt, mit professionellen Übersetzungen zur Gewährleistung der Konsistenz. Die Teilnehmenden, im Alter von 22 bis 48 Jahren, umfassen 14 afghanische und 6 eritreische Geflüchtete, die zwischen 2013 und 2019 nach Deutschland kamen. Sieben Interviewpaare bestehen aus zwei erwachsenen Mitgliedern desselben Haushalts, wodurch familiäre Dynamiken bei Migrationsentscheidungen beleuchtet werden. Die Studie fokussiert auf persönliche Migrationserfahrungen – von den Ausgangsbedingungen in den Herkunftsländern und den Transitphasen bis hin zur Ankunft und Integration in Deutschland sowie zukünftigen Perspektiven. Alle Interviews wurden transkribiert, ins Englische übersetzt, anonymisiert und stehen für die wissenschaftliche Sekundäranalyse zur Verfügung.Bundesministerium für Familie, Senioren, Frauen und Jugend (BMFSFJ
Tourismus und Lebensqualität: Wahrgenommene Belastungen und adaptive Strategien der Einwohner:innen in Kühlungsborn
No full textTourismus bewirkt nicht nur Chancen, sondern auch Herausforderungen für Einwohner:innen in Destinationen. Diese Studie untersucht basierend auf qualitativen Interviews mit Einwohner:innen in Kühlungsborn, wie diese den Tourismus und seine Auswirkungen erleben, welchen Einfluss dieser auf ihre wahrgenommene Lebensqualität hat und welche Anpassungsstrategien angewendet werden, um mit touristischen Auswirkungen umzugehen. Die Ergebnisse zeigen, dass die Einwohner:innen persönliche Vor- und Nachteile wahrnehmen, wobei negative Auswirkungen nicht immer als Belastung betrachtet werden. Verhaltensmäßige und kognitive Anpassungsstrategien sind dabei zentral, um die Belastungswahrnehmung zu reduzieren. Somit wird wahrgenommen, dass der Tourismus einen positiven und negativen Einfluss auf die eigene Lebensqualität hat. Für einige überwiegen die Vorteile, andere sehen positive und negative Aspekte ausgeglichener. Ein negativer Einfluss auf die Lebensqualität wird durch Anpassungsstrategien und das Höhergewichten von Vorteilen verhindert. Zwar sind Anpassungsstrategien kurzfristig wirksam gegenüber Belastungen, mit weiterem Wachstum könnten sie allerdings an Grenzen stoßen. Eine nachhaltige Tourismusentwicklung, die die Balance zwischen wirtschaftlichen Interessen und der Lebensqualität der Einwohner:innen langfristig stützt, ist daher zentral
The impact of anthropogenic drivers on benthic ecosystem functions in a changing North Sea
No full textMacrozoobenthos play a crucial role in soft-sediment ecosystems like the North Sea by driving processes such as bioturbation (physical mixing of sediments), bioirrigation (active flushing of water into sediments), and trophic interactions (e.g., predation). These functions are essential for nutrient cycling, primary productivity, and benthic–pelagic coupling. However, benthic communities face various anthropogenic drivers, including rising temperatures, increasing organic enrichment, and indirect impacts of commercial fishing such as mesopredator release. Given that these drivers alter benthic activity, they likely also influence the ecosystem functions that benthos facilitate. Accordingly, this thesis addresses empirical knowledge gaps by integrating experiments and surveys using benthic model organisms to elucidate mechanistic links between these drivers and ecosystem functioning. Manuscripts I and II examined how temperature affects bioturbation, bioirrigation, and related nutrient fluxes. Using luminophore and bromide tracers inside incubation cores in a mesocosm tank setup, the studies quantified sediment reworking and irrigation rates of key benthic species. Warmer temperatures increased bioturbation, boosting oxygen consumption within the sediment and nutrient effluxes (Manuscript I). The abundant lugworm Arenicola marina also shifted from dominant bioirrigation activity at 15 °C to bioturbation at 20 °C, indicating a sensitivity of ecosystem processes to warming (Manuscript II). These findings suggest that rising sea temperatures may initially enhance Wadden Sea ecosystem functioning by intensifying faunal activity and strengthening coupling between the sediment–water interface. Manuscripts III and IV explored how organic enrichment influences benthic ecosystem functions using in situ microcosm incubations and different species combinations. Algal material represented coastal enrichment, while particulate organic matter (POM) reflected offshore enrichment conditions. Elevated temperature and algal enrichment enhanced bioturbation by the intertidal amphipod Corophium volutator. However, an upper threshold was reached under 15 °C, beyond which further organic enrichment likely results in a suppression of activity (Manuscript III). In parallel, POM enrichment indirectly boosted bioturbation by Corophium multisetosum by providing the shrimp predator Crangon crangon with an alternative food source, reducing predation pressure on the amphipod (Manuscript IV). These findings underscore both direct and indirect enrichment effects on bioturbation, with potential cascading impacts on broader benthic ecosystem functioning. Finally, to assess the impact of mesopredator release on benthic communities, Manuscript V examined the diet of the flatfish Buglossidium luteum. Its population has grown due to milder winters and overfishing of predators and competitors, making it a significant mesopredator likely exerting strong pressure on the benthos. Stomach content analysis, combining DNA metabarcoding and traditional morphological methods, was paired with benthic infauna data from sampling sites. Results revealed a diverse diet of 164 taxa, mainly crustaceans and polychaetes, with clear spatial variation in prey composition. This highlights B. luteum as a highly opportunistic feeder, which likely facilitates its ongoing success. Correlations with infauna data also suggest lower mobility than previously assumed. Given continued warming and fishing pressure in the North Sea, this small flatfish is poised to maintain or increase its predation pressure, tightening trophic linkages in benthic food webs. Overall, this thesis demonstrated that anthropogenic drivers (rising temperatures, enrichment, and mesopredator release) intensify ecosystem functions by boosting bioturbation, nutrient cycling, and trophic transfer. This creates a positive feedback loop; enhanced bioturbation drives organic matter remineralization and primary productivity, which, in turn, fuels more benthic activity. Essentially, these animals sustain their own productivity by reinforcing bentho-pelagic coupling while also serving as abundant resources for higher trophic levels. While the benthic system is generally robust, signs of emerging thresholds were observed under combined drivers, with species like lugworms and corophiid amphipods showing stress at high temperatures or enrichment levels. Rather than a clear tipping point, the soft sediment environment of the North Sea demonstrates partial compensation through behavioural and functional adjustments, highlighting its nonlinear response to change. This integrated perspective calls for multi-driver experiments and continuous environmental monitoring, and provides a compelling glimpse into the future of North Sea benthic ecosystem dynamics
Exploring the effects of amyloid beta (Aβ) and Tau aggregation on neuronal activity and proteotoxicity in C. elegans
No full textProtein misfolding and aggregation in the human brain are key cellular hallmarks of neurodegenerative diseases, including Alzheimer’s disease (AD). At the cellular level, AD is characterised by the formation of extracellular amyloid beta (Aβ) plaques and neurofibrillary tangles (NFTs) of hyperphosphorylated Tau protein, leading to the neuronal degeneration and cognitive decline. Evidence suggests that amyloid formation and structural abnormalities in patients’ brain begin up to 20 years before clinical symptoms appear. My research aimed to correlate the aggregation and off-folding pathway of Aβ1-42 and mutant Tau with the onset of neuronal decline using C. elegans as a model system. First, I developed and characterised a novel C. elegans Tau model pan-neuronally expressing human Tau with the patient-derived mutations P301L and V337M (TauP301L,V337M). I showed that TauP301L,V337M aggregates with the progression of aging and exhibits multiple disease-related phenotypes. To study neuronal activity related to TauP301L,V337M and Aβ1-42 in C. elegans, I used a panneuronal GCaMP6m C. elegans strain. I observed that the decline of neuronal activity precedes the onset of both TauP301L,V337M and Aβ1-42 aggregation, with muscular Aβ1-42 expression exhibiting similarly strong detrimental effect on neuronal activity as Aβ1-42 expression in neurons.
The protein homeostasis (proteostasis) network aims to prevent the toxicity of aberrant proteins through the interplay of molecular chaperones and protein degradation systems. While intracellular chaperones assist in protein folding, refolding of misfolded proteins, preventing aggregation and disaggregating amyloids, little is known about mechanisms contributing to a functional proteome in the extracellular space. Therefore, I investigated the role of the two novel, potential extracellular modifiers (ECMs) - LYS-3 and CLEC-1 - on the aggregation and toxicity of Aβ1-42 using C. elegans as a model system. Knockout of lys-3 and clec-1 decreased Aβ1-42 aggregation in young adult animals, improved development and lifespan and reduced Aβ1-42 spreading to distal tissues. Surprisingly, these findings suggest that LYS-3 and CLEC-1 contribute to Aβ1-42 aggregation and toxicity by promoting amyloid spreading. Further studies are necessary to fully unravel the nature and mechanisms of LYS-3 and CLEC-1 functionality
Conflict and exclusion in Northern Brazil's marine fisheries: relational perspectives on governance and access
No full textArtisanal fisheries play a crucial role in sustaining livelihoods and providing high-quality protein to millions of people in the Brazilian Amazon coast. However, artisanal fishers’ livelihoods are threatened by declining fish stocks, the privatization of coastal and ocean areas, and exclusion from decision-making processes. This thesis examines how exclusionary governance in marine fisheries in Bragança, Pará, northern Brazil, perpetuates unequal access to fish and fisheries for artisanal fishers. Drawing from scholarship in fisheries management, political ecology, and marine social sciences, the thesis posits that the state's inability to support and protect the livelihoods and well-being of artisanal fishers, combined with the monopolization of fishery resources and benefits by a local fishing elite and the erosion of local representation to address these issues, perpetuates inequality and marginalization of fishers along Brazil's Amazonian coast. The thesis explores these issues in an introduction and three empirical articles.
The thesis first traces key historical elements pertaining to marine fisheries governance in Brazil, and in the Amazon region in particular, which directly impact artisanal fishers' access to fish and fisheries in contemporary times. Article 1 presents a systematic review analysis of the literature in marine social sciences, which explores the main themes and methodological approaches used in the study of ocean and marine conflicts. Article 2 uses a participatory network mapping approach (adapted from Schiffer & Hauck 2010) and builds on the Theory of Access (Ribot & Peluso 2003), to examine local actors’ perceptions of how current fisheries governance affects artisanal fishers’ ability to access fish and fisheries in Bragança. Article 3 is a case study of the governance of the large-scale pargo fishery (Caribbean red snapper, Lutjanus purpureus). Drawing on key stakeholders’ perceptions on the state of the pargo fishery and its governance, Article 3 examines how competing narratives reflect distinct views and approaches to equity. It emphasizes the marginalization of fishers' voices and concerns in decision-making processes.
By analyzing the dynamics of access struggles in artisanal fisheries in the Brazilian coastal Amazon, this thesis argues for the recognition of the multidimensional nature of exclusion in fisheries -exclusion no longer as a mere absence of rights, but as a dynamic, contested and relational process embedded in broader governance contexts. This perspective challenges reductionist conceptualizations of the Brazilian amazon’s marine fisheries as open access systems ensuing from a supposed historical absence of the state. Formal coastal and marine governance in the Brazilian Amazon has historically operated and operates in a way that essentially restricts or obstructs artisanal fishers’ access to fish and fisheries. Meanwhile, other fishing actors, who are often capital-intensive, exert greater control over access to fishing resources and benefit disproportionately from their use. This thesis concludes that equity considerations need to be more explicitly incorporated as a normative concern into fisheries governance frameworks in the Brazilian Amazon region. This requires a shift to an access-enabling governance for artisanal fisher(ie)s. Only by recognizing that ecological viability is conditioned to social equity, attuned to the lived realities and political agency of those most affected, can sustainable fisheries be achieved
How to (not) disentangle personality constructs: scrutinizing longitudinal, multi-rater, and behavioral genetic approaches
No full textTo disentangle the characteristic patterns that shape the uniqueness of individuals, personality is often regarded as a dynamic system composed of some more basic, stable, and consistent person-only characteristics as well as more specific and environmentally malleable person-in-environment characteristics. Prior research proposed testable criteria for examining the extent to which personality constructs might rather reflect person-only or person-in-environment characteristics. These criteria involve various empirical properties of constructs, such as their stability, observability, or heritability. Appropriate examinations hereof require comprehensive empirical data, encompassing longitudinal data from multiple measurement occasions, multi-rater data from different rater perspectives, and behavioral genetic data from twins and their family members. In the current work, I scrutinize selected methodological approaches using these three data sources in terms of their benefits and pitfalls and thus the conclusions they allow to be drawn (or not). To this end, I focus on the structural equation models that were applied within the three empirical research papers of the present dissertation, and illustrate their application by the aim of disentangling whether the potential person-only characteristic emotional stability differs from the three self-related schemata self-esteem, self-efficacy, and internal locus of control. It crystallizes that the benefits and pitfalls of any methodological approach also depend on the nature of the constructs examined. Longitudinal approaches allow to decompose variance in state measures into stable and state-specific components. Both components, however, might be more or less informative for more or less stable characteristics. Associations between constructs, as examined in cross-lagged panel models, could thus differ depending on the part of variance between which the links are estimated. Multi-rater approaches allow to decompose variance in personality measures into intersubjectively objective and rater-specific components. However, intersubjectively objective components might represent valid variance in easily observable characteristics, while rater-specific components might contain relevant and valid information on more contextualized characteristics. Overlaps of intersubjectively objective components between constructs, as examined in multitrait-multimethod models, could thus question distinctiveness or hint that constructs overlap in a specific rater-consistent part. Behavioral genetic approaches allow variance decomposition in genetic and environmental parts, whereas these components might be estimated differently based on classical twin or nuclear twin family models. Besides, genetic variance in more contextualized characteristics may be explained by more basic ones, making sole heritability estimates only conditionally insightful. Examining constructs in terms of their unique and common heritability, using common pathway models, may thus be additionally relevant. Overall, it proves essential that variance in personality measures results from an interplay of stable and state-specific, construct- and rater-specific, as well as genetic and environmental variance. Combining multiple perspectives on the sources of individual differences could serve to examine and disentangle the properties of constructs more accurately. The current dissertation therefore reveals the need for more integrative approaches using longitudinal, multi-rater, and behavioral genetic data within future research into personality differences
Reflexion von Physikunterricht. Entwicklung und Validierung eines Testinstruments mit Assessment-Feedback zur Reflexionsfähigkeit Physik-Lehramtsstudierender
No full textDie Fähigkeit zur Unterrichtsreflexion stellt eine für Lehrkräfte zentrale Fähigkeit zur Professionalisierung und Verbesserung der Unterrichtsqualität dar. Es liegen Befunde vor, dass diese Fähigkeit bei angehenden Lehrkräften häufig nur gering ausgeprägt ist, sodass Bedarf zu ihrer Förderung besteht. Wie sich die Reflexionsfähigkeit entwickelt und im Lehramtsstudium gefördert werden kann, ist allerdings weitgehend unklar.
In dieser Arbeit wird ein Test zur validen Erfassung der Reflexionsfähigkeit angehender Physiklehrkräfte mit anschließendem Feedback für Teilnehmende entwickelt und evaluiert. Die Evaluation erfolgt auf Grundlage von N = 192 Testbearbeitungen sowie von Interviews, die die kognitiven Prozesse während der Testbearbeitung und die Interpretation des Feedbacks durch Teilnehmende erheben. Weiterhin werden eine latente Profilanalyse durchgeführt und Zusammenhänge zur Noticingfähigkeit u.a. im Cross-Lagged-Panel-Design analysiert, um weiterführende Erkenntnisse zur Entwicklung der Reflexionsfähigkeit zu gewinnen.
Mit dem positiv evaluierten Test kann die Reflexionsfähigkeit valide erhoben und rückgemeldet werden. Als Ergebnis der Profilanalyse werden vier aufsteigende Fähigkeitsstufen identifiziert, die u.a. Zusammenhänge zum Umfang absolvierter Schulpraktika aufweisen. Ein weiteres Ergebnis ist, dass die Noticingfähigkeit zur Entwicklung der Reflexionsfähigkeit beiträgt und daher künftig im Rahmen ihrer Förderung berücksichtigt werden sollte
Advancing the applicability to extract physiological parameters using Arterial Spin Labeling
No full textArterial Spin Labeling (ASL) is a non-invasive MRI technique for measuring perfusion without the need for contrast agents, as it utilizes the blood itself. ASL can quantify not only blood flow but also other hemodynamical parameters, such as transit times and exchange rates within organs.
The first part of this work introduces an extended quantification model, incorporating an additional intravoxel transit time parameter that differentiates between transit and exchange mechanisms. Conducted simulations show that neglecting transit effects leads to a compensation in the exchange parameter.
The second part of this thesis explores the use of velocity selective ASL for robust extracerebral measurements. This sophisticated technique offers flexibility for imaging organs with low blood flow velocities or unclear feeding vessels. The focus is on breast and liver imaging
Regisseure des Reiseglücks. Berufsfeld Reiseleitung: Rahmenbedingungen, Erfahrungen und Perspektiven
No full textDie Studie liefert eine Bestandsaufnahme auf qualitativer Basis zum Berufsfeld Reiseleitung. Sie wurde im Jahr 2006 an der Hochschule Bremen durchgeführt und stützt sich auf 30 Interviews. Die Sichtweise der Akteure auf das Feld spiegelt sich in den Antworten der Befragten. Die Ergebnisse zeigen das hohe Engagement vieler Reiseleiter und die immer noch kritische berufliche Absicherung
Research-based development of media elements for professional development on the use of digital media in science education
No full textDie Dissertation untersucht die forschungsbasierte Entwicklung asynchroner, webbasierter Mikrofortbildungen für naturwissenschaftliche Lehrkräfte zur Integration digitaler Medien in den Unterricht. Angesichts der wachsenden Bedeutung digitaler Kompetenzen und des Mangels an geeigneten Fortbildungsangeboten wurde ein flexibles, praxisorientiertes Konzept entwickelt, das Lehrkräften zeit- und ortsunabhängige Lernmöglichkeiten bietet. Grundlage bilden theoretische und bildungspolitische Analysen, eine systematische Literaturrecherche zu Gestaltungsmerkmalen asynchroner Fortbildungen sowie die empirisch gestützte Entwicklung und Erprobung von Mikrofortbildungseinheiten. Die Ergebnisse zeigen, dass das Format praxisnahe Impulse zur didaktisch sinnvollen Nutzung digitaler Medien geben und damit zur Professionalisierung von Lehrkräften beitragen kann. Die Arbeit liefert ein Modell zur Weiterentwicklung nachhaltiger, effektiver Fortbildungsformate und unterstützt die Umsetzung der KMK-Strategie „Bildung in der digitalen Welt“