OOPS - Oldenburger Online-Publikations-Server (Univ. Oldenburg)
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Engineeringprozess für Virtualisierte Dienste in Smart Grids
Full text linkDie dezentrale Energieerzeugung durch erneuerbare Quellen erfordert neue Planungs- und Betriebsführungsprozesse. Dafür müssen Verteilnetze digital aufgerüstet und über IKT zu einem Cyber-Physischen Energiesystem (CPES) vernetzt werden. So können netzdienliche Aufgaben wie Spannungshaltung oder Redispatch umgesetzt werden. Ortsnetzstationen können digitale Geräte wie IEDs und RTUs zur Fernüberwachung nutzen. Die wachsende Zahl solcher Geräte erhöht die Komplexität. Konzepte wie Virtualisierung, Microservices und Edge-Computing können dabei unterstützen. Diese Arbeit beschreibt ein Virtualisierungskonzept unter Verwendung von Containerisierung für Stationsgeräte und ergänzt eine zentrale Verwaltungseinheit zur Steuerung über mehrere Stationen hinweg. Das Konzept wurde in einen IEC-61850-Prozess integriert. Ein Feldtest mit elf digitalisierten Stationen bestätigen die Praxistauglichkeit
The effect of NDP-MSH microparticles on the integrity of the blood-brain barrier
Full text linkMultiple sclerosis (MS) is a chronic inflammatory neurodegenerative disease of the central nervous system (CNS) characterized by a disrupted blood-brain barrier (BBB), which is composed of endothelial cells (EC) connected by tight junction (TJ) proteins like claudin 5 and zonula occludens 1 (ZO-1). This structure prevents harmful substances and immune cells from entering the CNS. In both MS and its mouse model, experimental autoimmune encephalomyelitis (EAE), reduced TJ molecule expression increases EC permeability, allowing immune cell infiltration, which produce pro-inflammatory cytokines and cause neuronal damage. Nle4-D-Phe7-α-MSH (NDP-MSH), a synthetic alpha melanocyte-stimulating hormone analogue, ameliorates EAE by binding to melanocortin 1 receptor (MC1R), reducing immune cell infiltration and pro-inflammatory cytokine secretion. Moreover, NDP-MSH was shown to have neuroprotective capacities. However, its effect on BBB integrity remains unclear. This study proposes that enhancing BBB integrity through NDP-MSH reduces immune infiltration, protects neurons, and therefore ameliorates EAE. In accordance with animal welfare law, EAE was induced in C57BL/6 mice and MC1Re/e mice, having a non-functional MC1R, using myelin oligodendrocyte glycoprotein (MOG) peptide. Due to the short half-life of NDP-MSH, the compound was encapsulated into PLGA microparticles (NDP-MSH mp) and its effect was tested in these mice. NDP-MSH mp ameliorated EAE symptoms in an MC1R-dependent manner. Moreover, immunofluorescence staining of brain sections revealed a marked increase in claudin-5 and ZO-1 expression, along with significantly enhanced co-localization in C57BL/6 mice, but not in MC1Re/e mice. In support of this, qPCR experiments confirmed a significant upregulation in Cldn5, Tjp1 mRNA expression and showed significant increase in Ocln and Cdh5 mRNA expression in C57BL/6 mice after NDP-MSH mp treatment, by binding to MC1R, indicating enhanced BBB integrity.
Furthermore, trans-endothelial electrical resistance (TEER) assays on murine brain microvascular EC (MBMEC) treated with TNFα and IL-1β demonstrated increased electrical resistance after NDP-MSH mp treatment, suggesting improved EC monolayer integrity. Notably, this effect was abrogated in MBMEC isolated from MC1Re/e mice. Additionally, qPCR analysis revealed elevated Cldn5 and Tjp1 expression in C57BL/6 mice, while MC1Re/e MBMEC showed no significant changes, indicating MC1R-mediated effect.
RNA sequencing of brain CD45+ cells from mice with active EAE indicated decreased Vegfa expression, encoding vascular endothelial growth factor A, in C57BL/6 mice, suggesting its involvement in the molecular pathway mediating the effects of NDP-MSH mp. These findings reveal that NDP-MSH mp enhances BBB integrity in EAE via MC1R binding, might provide a potential therapeutic approach for neurodegenerative diseases like MS through PLGA microparticle delivery. Further investigation of the molecular mechanism should be conducted as well as generating PLGA nanoparticle containing NDP-MSH will probably help in improving the therapeutic outcomes
Die komplexe und ambivalente Rolle des Scrum Masters im agilen Management. Eine Analyse der (erfolgs-)kritischen Kompetenzanforderungen
Full text linkDie Dissertation untersucht Charakteristika und Herausforderungen der Rolle des Scrum Masters, die sich im Ergebnis als komplex und ambivalent herausstellt. Die Rolle ist mit einem umfangreichen und heterogenen Aufgaben- und Tätigkeitsspektrum verbunden. Rollenkonflikte und -stress entstehen dadurch, dass Scrum Master das Team lateral führen sollen, ohne hierarchische Macht zu besitzen, und dabei den Spagat schaffen müssen zwischen der klaren Anleitung und Strukturierung des Prozesses und des Teams sowie der dienenden Förderung und Unterstützung der Teammitglieder. Die Rolle ist daher mit umfangreichen und hohen Kompetenzanforderungen verbunden. Diese wurden auf Basis einer Interviewstudie mittels Critical Incident Technique und ergänzend anhand einer Stellenanzeigenanalyse erhoben. Im Ergebnis ließen sich kritische Kompetenzanforderungen in Form von konkreten Teilkompetenzen und damit verbundenen Verhaltensankern festlegen, die vorwiegend aus dem sozial-kommunikativen Bereich stammen
Individual differences in musical scene analysis abilities across normal-hearing and hearing-impaired individuals
Full text linkIn this dissertation, individual differences in Musical Scene Analysis (MSA)—the ability to perceptually organise concurrent sound sources within polyphonic musical mixtures—were investigated across four empirical studies. The first study surveyed hearing health among professional and amateur musicians, revealing high rates of hearing-related difficulties. The second study developed and validated an adaptive MSA test using realistic musical mixtures, demonstrating good reliability and sensitivity to hearing thresholds. The third showed that musical training enhances MSA abilities, while ageing and hearing loss reduce performance; working memory capacities showed only weak, non-robust effects. The fourth applied the MSA test to hearing aid users, revealing that dynamic range compression differentially affects MSA performance and sound quality. Together, the findings establish MSA as a construct shaped by auditory, cognitive, and experiential factors
Subjektive Theorien zu Bildung auf Reisen. Eine empirische Untersuchung zu potenziellen Bildungs- & Lerneffekten auf Reisen.
Full text linkDie Dissertation untersucht das Bildungspotenzial von Reisen unter Berücksichtigung gesellschaftlicher Veränderungen und erweiterter Konsummöglichkeiten. Nach einer interdisziplinären Begriffsbestimmung von Bildung, Kultur und Lernen sowie einer Analyse relevanter Tourismusarten wurden Forschungsfragen zur Wahrnehmung bildungsbezogener Reiseangebote entwickelt. Empirisch wurde ein Mixed-Methods-Ansatz genutzt: Eine standardisierte Befragung von 310 Reisenden zeigte, dass Reisen den Horizont erweitern, Reflexionsprozesse anregen und interkulturelles Lernen fördern, jedoch auch als Erholung betrachtet werden. Expert:inneninterviews ergänzten diese Ergebnisse, zeigten aber Defizite in der touristischen Angebotsgestaltung. Die Studie bestätigt, dass Reisen Bildungs- und Lerneffekte ermöglichen, deren Nachhaltigkeit jedoch von intrinsischer Motivation und Reflexionsfähigkeit der Reisenden abhängt
Cooperative Software Verification
Full text linkSoftware plays an important role in our daily lives. To ensure that a program fulfills specific requirements, software verification is used. Cooperative software verification aims to combine the strengths of existing components on a conceptual level so that they work together in a loosely coupled manner to solve a task.
This thesis presents a systematic analysis of the effects of using cooperative software verification. We develop and evaluate three concepts for cooperative software verification: The sequential concept, CoVEGI, allows components to cooperate on invariant generation, a core task in software verification. The cyclic concept is based on a decomposition of the widely used CEGAR scheme. In the decomposed version, C-CEGAR, three stateless components cooperate via existing verification artifacts. Finally, we propose the concept of ranged program analysis, which enables the parallel composition of arbitrary verifiers. We experimentally demonstrate the advantages of cooperative verification for each of the three approaches
Sedimentology and sediment dynamics in tidally dominated areas influenced by anthropogenic utilization
Full text linkCoastal regions face growing risks from climate change, erosion, and flooding, especially in tide-dominated areas. Hard protection structures like groynes alter hydrodynamics and sediment transport, but long-term effects remain poorly understood. This study examines the Harle tidal inlet on the German North Sea coast, influenced by a groyne from Wangerooge. Sediment analysis and mapping reveal altered transport patterns, more stable sedimentation, and diverse benthic habitats. Compared to the unaffected Otzumer Balje, Harle shows more bioclastic material and a complex channel system. Heavy metal analysis indicates fine sediments near harbors and channels contain higher concentrations, especially arsenic, linked to natural and anthropogenic sources. The groyne significantly affects flow, erosion, sediment distribution, and contaminant accumulation
The Influence of a Positive Psychological Intervention Programme on Kenyan First-Year University Students’ Well-Being: A Mixed Methods Study
Full text linkTransitioning into higher education is often accompanied by new responsibilities and expectations that can impact the well-being of students. Using a mixed methods research design, the study aimed to investigate the influence of a 7-week positive psychological intervention (PPI) programme on the well-being of Kenyan first-year university students. The quantitative data indicated that the intervention group experienced significant improvements in well-being compared to the control group. There was a significant decrease in symptoms of depression and anxiety in the intervention group compared to the control group. The qualitative findings indicated improvements in well-being facilitated by factors such as the programme's structure and positive connections formed. Following the findings, guidelines were developed to support students’ well-being while implementing PPIs
Correlated activity in the mammalian retina
Full text linkVisual signals are transduced by photoreceptors and relayed to retinal ganglion cells (RGCs) through interneurons. RGC activity reaches the brain via the optic nerve, forming the basis of vision. RGCs comprise diverse types with specialized functions. These cells do not act in isolation. Their interactions can yield correlated firing among neighboring RGCs, shaped by stimuli and network properties. Using large-scale multi-electrode array recordings from guinea pig retina, this thesis examines spike correlations within and between RGC types and spiking amacrine cells. Three studies address fast reciprocal correlations from gap-junction coupling, interactions between polyaxonal amacrine cells and RGC populations, and correlations arising from shared input. Together, the analyses describe circuit motifs associated with synchrony of retinal activity
