Hochschule Bonn-Rhein-Sieg
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Benchmarking the performance of healthcare systems in the provision of childhood immunization services in sub-Saharan Africa from 2016 to 2019
No full textChildhood immunization rates in many sub-Saharan African (SSA) countries have stagnated, trailing behind other global regions. This study evaluates the efficiency of childhood immunization service delivery and its environmental determinants in 36 SSA countries from 2016 to 2019. We apply data envelopment analysis (DEA) to measure technical efficiency, truncated bootstrap regression to assess influencing factors, and the Malmquist productivity index (MPI) to track productivity changes over time. Findings show that 36% of SSA countries have not met the World Health Organization’s 90% immunization target. The bias-corrected technical efficiency of immunization services is 0.895 (95% CI: 0.878–0.912). However, an MPI value of 0.715 indicates a 28.5% decline in total factor productivity, mainly due to slow technological advancements. Efficiency is positively associated with female education, governance quality, social health insurance coverage, population density, and healthcare access, while per capita GDP negatively correlates with efficiency. Despite high efficiency in some SSA countries, productivity remains hindered by technological limitations. We recommend that governments and international partners prioritize investments in technology and healthcare infrastructure to enhance productivity and improve immunization coverage
Amphiphilic Fluoro‐Functionalized Cellulosic Materials: Synthesis, Characterization, and Organic Dye Adsorption Properties
Get PDFThe growing interest toward biopolymers application in amphiphilic conditions prompts one to explore the preparation of fluorinated cellulosic materials. Cellulose (CE) and carboxymethylcellulose (CMC) are functionalized with highly fluorinated pendants, through a nucleophilic aromatic substitution on 3-pentadecafluoroheptyl-5-pentafluorophenyl-1,2,4-oxadiazole (FOX) leading to the corresponding fluorinated biopolymers CE-FOX and CMC-FOX. Structural and thermal stability confirm covalent attachment of the fluorinated moiety onto the cellulosic skeleton and highlighted an interesting 2D texture of the CMC-FOX material. Hybrid and amphiphilic features of CE-FOX and CMC-FOX, are confirmed by water and oil contact angle measurements. Applications as adsorbent material for organic contaminants from an aqueous solution are tested by previously incorporating the functional biopolymer into sodium alginate (SA) hydrogel beads. Rhodamine B (RhB) is used as a model wastewater pollutant. Fluoro-functionalization led to a three- to eightfold increase in the dye-removal efficiency of the SA-incorporated biopolymer with respect to the corresponding non-fluorinated material (from 11% to 48% for SA/CE vs SA/CE-FOX beads and from 11% to 94% for SA/CMC vs SA/CMC-FOX beads). Recyclability tests show good residual performance of SA/CMC-FOX beads after seven desorption/reuse cycles opening the way to more sustainable adsorbing processes for the removal of emerging pollutants from contaminated water
Simulation und Auslegung eines Reaktors für die thermochemische Energiespeicherung auf Basis des Ca(OH)2/CaO-Reaktionssystems
Get PDFFür die Defossilisierung des Heizungssektors ist die effiziente Speicherung thermischer Energie über lange Zeiträume hinweg essentiell. Das Reaktionssystem von Calciumhydroxid (Ca(OH)2), Calciumoxid (CaO) und Wasserdampf (H2O) gilt als vielversprechend für den Einsatz in thermochemischen, saisonalen Energiespeichern. Die Entwicklung effizienter Speicherreaktoren ist aufgrund der schlechten Wärmeleitfähigkeit des Speichermaterials jedoch nach wie vor eine Herausforderung, welcher bislang mit komplexen Wärmeleitstrukturen und mechanischer Fluidisierung begegnet wurde. Beide Ansätze können den Wärmeeintrag in das Speichermaterial zwar verbessern, allerdings eignen sich diese Reaktoren aufgrund ihrer Komplexität nur unzureichend für den Einsatz in Einzelgebäuden.
Grundlage dieser Arbeit ist daher ein neuartiges Konzept für einen direkt durchströmten Festbettreaktor, bei welchem das Speichermaterial in luftdurchlässigen Gitterkörben ruht. Die endotherme Beladung des Speichers erfolgt dabei über elektrische Heizstäbe im Reaktionsraum, während die Schüttung bei der exothermen Entladung mit einem Wasserdampf-Luft-Gemisch durchströmt wird.
Ziel dieser Arbeit ist die numerische Simulation des Wärmetransports im Reaktor mit Comsol Multiphysics. Durch Parametervariation wurden die wesentlichen Wärmetransportmechanismen bei der Speicherbe- und entladung identifiziert und der Einfluss geometrischer sowie materialbezogener Größen, wie bspw. dem Pelletdurchmesser oder den Abmessungen der Schüttung, analysiert.
Die Ergebnisse dieser Arbeit zeigen, dass ein effizienter Wärmeeintrag durch natürliche Konvektion in die ruhende Schüttung erfolgt, wenn die Permeabilität ebendieser hoch ist. Eine Erhöhung der Temperatur im Reaktionsraum verbessert den Wärmeeintrag ebenfalls, während jegliche Behinderungen des Fluidstroms im Reaktorinneren den Wärmeeintrag verschlechtern. Darüber hinaus beeinträchtigt eine Zunahme der Schüttungshöhe den Wärmeeintrag in diese erheblich, während die negativen Auswirkungen bei einer Verbreiterung der Schüttungskörbe – insbesondere aufgrund der erhöhten Speicherkapazität – als moderat eingestuft wurden. Es konnte gezeigt werden, dass die Strömung innerhalb der Schüttung der limitierende Faktor ist. Für einen guten Wärmeaustrag aus der Schüttung sollte diese mit dem Reaktionsgas direkt durchströmt werden, da die Wärmeübertragung von den Pellets auf das Fluid so am höchsten ist.
Mit den erstellten Simulationsmodellen wurde abschließend die konstruktive Geometrie des Reaktors ausgelegt, welcher derzeit gefertigt und anschließend experimentell vermessen wird
The role of university entrepreneurship support and student diversity in student entrepreneurial intention: a social identity theory perspective
Get PDFOne of the most significant shortcomings of the extant literature is the dearth of conceptualizations and empirical testing pertaining to entrepreneurial diversity and the underlying social identities. Accordingly, this research aims to empirically investigate the influence of entrepreneurial support at the university level on students' entrepreneurial intention from a diversity and social identity perspective. The research utilizes fsQCA (fuzzy set Qualitative Content Analysis) and a set of observable and underlying diversity factors (gender, age, previous academic performance, and parental educational attainment) to elucidate the causal structures that influence the formation of entrepreneurial intention among university students. The findings illustrate the multifaceted nature of the entrepreneurial intention formation, with first-generation status being a necessary condition for low entrepreneurial intention. The findings underscore the importance of university entrepreneurial support in the formation of entrepreneurial intention especially for younger students and first-generation students. The study contributes to the literature on entrepreneurial diversity and social identities in entrepreneurship by identifying the underlying factors that contribute to high and low entrepreneurial intention among university students
RAGatar: Enhancing LLM-driven Avatars with RAG for Knowledge-Adaptive Conversations in Virtual Reality
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Geschäftsprozesse analysieren und optimieren: Praxistools zur Analyse, Optimierung und Controlling von Arbeitsabläufen
No full textDie 3. Auflage dieses Buchs zeigt konkret auf, was Geschäftsprozessmanagement ist und wie man es nutzen kann. Hierzu werden die zentralen Aspekte erklärt und praxistaugliche Tools anhand von Beispielen vorgestellt. Erleichtern Sie sich die tägliche Praxis der Analyse und Optimierung von Geschäftsprozessen
Soluble CD21: From Shedding to Autoimmunity
Get PDFBackground: Soluble CD21 (sCD21) is the product of metalloprotease-mediated proteolysis of CD21, a mechanism in which the entire extracellular domain of CD21 is shed from the cell surface. Through its retained ligand-binding ability and presence in human serum, sCD21 joins the growing list of surface proteins shed from the leukocyte cell surface which allows modulation of the immune response. Summary: sCD21 plays a multifaceted role in the body, including the promotion of inflammatory responses through receptor-ligand interactions with monocyte CD23, acting as a decoy receptor during Epstein-Barr virus infection preventing lymphoproliferation, and suppression of IgG and IgE responses by competitively inhibiting cell surface CD21. Clinical studies have shown that in comparison with healthy individuals, levels of sCD21 in serum are significantly altered in various diseases, highlighted by diverse viral infections, B-cell leukemias, and autoimmune disorders. Key Messages: Although findings of prevalence and functionality suggest sCD21 to be a key modulator of cellular and humoral immunity, questions remain about its origins and the regulation of its responses. Here, we aim to clarify and connect the advances in understanding sCD21 over time with emphasis on its generation by surface cleavage, binding partners, and functional roles. We also provide an outlook on its clinical significance and usage as a diagnostic target and therapeutic biomarker to monitor treatment efficacy in the context of chronic autoimmune disorders
Parameter-Efficient Fine-Tuning of Vision Foundation Model for Forest Floor Segmentation from UAV Imagery
No full textUnmanned Aerial Vehicles (UAVs) are increasingly used for reforestation and forest monitoring, including seed dispersal in hard-to-reach terrains. However, a detailed understanding of the forest floor remains a challenge due to high natural variability, quickly changing environmental parameters, and ambiguous annotations due to unclear definitions. To address this issue, we adapt the Segment Anything Model (SAM), a vision foundation model with strong generalization capabilities, to segment forest floor objects such as tree stumps, vegetation, and woody debris. To this end, we employ parameter-efficient fine-tuning (PEFT) to fine-tune a small subset of additional model parameters while keeping the original weights fixed. We adjust SAM's mask decoder to generate masks corresponding to our dataset categories, allowing for automatic segmentation without manual prompting. Our results show that the adapter-based PEFT method achieves the highest mean intersection over union (mIoU), while Low-rank Adaptation (LoRA), with fewer parameters, offers a lightweight alternative for resource-constrained UAV platforms
open5Gcube: A Modular and Usable Framework for Mobile Network Laboratories
No full textIn mobile network research, the integration of real-world components such as User Equipment (UE) with open-source network infrastructure is essential yet challenging. To address these issues, we introduce open5Gcube, a modular framework designed to integrate popular open-source mobile network projects into a unified management environment. Our publicly available framework allows researchers to flexibly combine different open-source implementations, including different versions, and simplifies experimental setups through containerization and lightweight orchestration. We demonstrate the practical usability of open5Gcube by evaluating its compatibility with various commercial off-the-shelf (COTS) smartphones and modems across multiple mobile generations (2G, 4G, and 5G). The results underline the versatility and reproducibility of our approach, significantly advancing the accessibility of rigorous experimentation in mobile network laboratories