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Essays in Empirical Economics
Get PDFThe dissertation, entitled Essays in Applied Economics, contains three chapters. Each chapter is an independent paper. Together, they examine important socioeconomic phenomena in Germany. The chapters use unique datasets and rigorous econometric methods to provide insights into different but interrelated aspects of applied microeconomics, from labor economics to internal migration and political economy. Together, these essays seek to contribute to our understanding of crucial issues related to labor market responses to global trade shocks, the effectiveness of migration policies, and the socioeconomic determinants of the election results of the far-right. They provide a comprehensive understanding of how economic and social factors interact to shape labor markets and political landscapes in contemporary Germany
Evaluation on the capabilities of MATLAB Simulink’s Embedded Coder for rapid prototyping of micro-controller based control systems for switching converters
Get PDFSwitching converters play a crucial role in modern power electronics, offering efficient voltage conversion in various electronic devices. This paper presents an approach to the rapid prototyping for micro-controller based control systems, applied to the buck-converter topology. The methodology utilized features from MATLAB Simulink and it’s Embedded Coder extension to model and implement the control system, enabling a simplified transition from simulation to hardware implementation. For this purpose the paper evaluates two control systems, namely the error-amplifier and the PID controller. Comparative analysis reveals insights on the startup behavior, RMS voltage, peak-to-peak voltage and maximum voltage. While the simulation outperformed the measurements of the hardware implementation in most parts, this paper still underscores the utility of MATLAB Simulink’s Embedded Coder for rapid prototyping and hardware-in-the-loop development of switching converter control systems
Multiport Converter in the Application Field of Fast Charging Stations
Get PDFThe concept of multiport converter as a building block for the DC/DC stage enables a fast charging station with multiple charging spots. The magnetic coupling of the output ports allows to reduce the required number of components in the DC/DC stage. However, the magnetic coupling between the output ports and the resulting mutual influence on the output characteristics, referred to as cross-coupling effects, impacts the converter’s performance. Particularly when confronted with substantial load variations among the output ports, the cross-coupling effects can deteriorate the efficiency of the multiport converter. The root cause for the cross-coupling effects is derived and it is shown that choosing an appropriate inductance ratio between the output ports and the input port is an effective way to reduce the cross-coupling effects. By reducing cross-coupling effects the full potential of multiport converters as a building block in fast charging stations can be exploited. Different strategies in transformer design process are illustrated to achieve the necessary inductance ratio. Apart from the usage as a building block for providing charging spots, the multiport converter can be used to integrate battery storage in fast charging stations. For an efficient integration of the battery storage, the concept of a multiport converter based on partial power processing is proposed. Compared to conventional full power processing converters, with partial power processing only a part of the power is transferred through the converter. This increases the efficiency of the converter and at the same time leads to a cost reduction. The special requirements for the design of partial power processing based multiport converters are evaluated
Immuntherapeutisches Co-Targeting von CD38 und CD47 bei der T-Zell Akuten Lymphoblastischen Leukämie
No full textDie Prognose der T-Zell akuten lymphoblastischen Leukämie (T-ALL) im Kindesalter hat sich in den letzten Jahren durch die Etablierung von Chemotherapieprotokollen deutlich verbessert. Im Rezidiv ist die Prognose der T-ALL aufgrund von Chemotherapieresistenzen nach wie vor sehr ungünstig, u.a. da es bisher keine zugelassene Antikörpertherapie zur Behandlung der T-ALL gibt. In einem präklinischen Modell mit de novo T-ALL Patient-derived Xenograft (PDX) wurde gezeigt, dass der CD38-Antikörper Daratumumab (Dara) das Überleben von Mäusen verlängert. Dara wirkt u.a. über die antikörperabhängige zelluläre Phagozytose (ADCP). Das Oberflächenprotein CD47, das auf T-ALL-Zellen stark exprimiert wird, vermittelt Makrophagen ein „don’t eat me“-Signal, was durch den Einsatz eines CD47-Antikörpers unterbunden werden kann. In dieser Arbeit wurde ein CD47-Antikörper (Hu5F9-IgG2σ) und Dara in vitro und in vivo in T-ALL Zelllinien, de novo T-ALL PDX und rezidivierten/refraktären (r/r) T-ALL PDX Zellen untersucht. In in vitro ADCP Assays mit T-ALL Zelllinien, de novo T-ALL PDX und r/r T-ALL PDX führte die Kombination beider Antikörper zu einem starken Anstieg der Phagozytose. In einem in vivo Modell mit de novo T-ALL PDX Zellen führte die Monotherapie mit Dara oder Hu5F9-IgG2σ zu einem verlängerten Überleben. In einem in vivo Modell mit r/r T-ALL PDX konnte Dara das Überleben nicht verlängern, Hu5F9-IgG2σ zeigte ein verlängertes Überleben und ein Langzeitüberleben in 3/11 Fällen. Die Kombination beider Antikörper führte in etwa 80% der Fälle zu einem Langzeitüberleben. Die Ergebnisse der Arbeit legen nahe, dass die Behandlung mit Dara und einem CD47-Antikörper eine vielversprechende Option in der Therapie der T-ALL darstellt, besonders bei rezidivierter und refraktärer Erkrankung
Eckpunkte einer realistischen Einwanderungspolitik: Die Perspektive der Regierungslehre
Get PDFProbleme, die politisch länger nicht gelöst werden, wie in diesem Fall dasjenige der ungeplanten, ungehinderten und ungesteuerten Zuwanderung, suchen sich früher oder später ihre Lösungen selbst. Um das zu verhindern, bedarf es statt einem nach wie vor herrschenden Schwarz-Weiß-Denken in der politischen Debatte einer differenzierten, realistischen und pragmatischen Lösungssuche. Vor diesem Hintergrund formuliert der Autor in diesem Beitrag 20. Eckpunkte, die zu einer Verständigung auf das nationale Interesse in der Einwanderungs- und Integrationspolitik beitragen können, woraus im Anschluss geeignete Strategien abgeleitet und effektive Maßnahmen ergriffen werden könnten
The interaction of asthma risk genes with cigarette smoke and their influence on airway morphology, physiology and signaling pathways in Drosophila melanogaster
Get PDFAsthma bronchiale is a chronic inflammatory airway disease with no intervention method or cure available. Its early life development is influenced by both host and environmental factors, which act independently but can also interact with each other. Genetic studies identified ORMDL3 and Scca1 as asthma risk genes associated with asthma development. Additionally, cigarette smoke (CS) exposure is a known environmental risk factor for asthma development in early life. In this study, the interaction of ORMDL and Scca1 with CS exposure was investigated in the airway epithelium of Drosophila melanogaster. Therefore, flies with airway-specific knockdown (KD) or overexpression (OE) of the gene orthologues of ORMDL3 and Scca1 were generated. Changes in larval tracheal morphology, larval and adult physiology and in the transcriptome of the airways were characterized. Results show that OE and KD of ORMDL cause mild morphological changes in the airway structure and influence physiological parameters. In interaction with CS exposure ORMDL OE led to massive changes in the airway epithelium. ORMDL KD interacted with CS exposure, which was reflected in sex-dependent changes in adult longevity. Scca1 KD caused only mild changes in interaction with CS exposure. Scca1 OE induced sex-dependent modifications of airway structure and had a strong impact on developmental traits. In interaction with CS exposure, morphology of airways was changed in males, while physiology was influenced in both sexes. The transcriptome of Scca1 OE flies was prone in a direction of inflammatory and stress signaling pathways at baseline. In interaction with CS, Scca1 OE caused the dysregulation of genes associated with inflammatory traits and airway remodeling
Full-Stokes equations: solution strategies and parameter identification with application to ice sheet models
Get PDFMelting of glaciers is an important factor in sea level rise. We try to estimate the future development of glaciers with simulations. They help us to prepare and evaluate the impacts of global warming on glaciers. These simulations should be as precise as possible. Thus, a high resolution and the implementation of many physical processes are necessary. The resulting large software codes need a lot of computation time and limit the resolution and the number of implemented physical processes. A realistic model should still be computationally affordable and physical parameters of the equations have to be known. Hence, we can improve predictions by developing new algorithms that reduce the computation time without reducing the accuracy of the results. The main computation time is used to calculate the velocity and pressure field of glaciers. The governing equations are called full-Stokes equations. In this thesis, we use that minimizing a convex functional is equivalent to solving the full-Stokes equations. We prove that Newton's method with Armijo step sizes for this functional finds a sequence converging to the unique solution of the full-Stokes equations. We only have to add a small diffusion term for this theoretical analysis. We also introduce approximately exact step sizes for Newton's method and the classical Picard iteration. We show that the approximately exact step sizes are better than the Armijo step sizes for all our tested benchmark experiments. Lastly, we focus on unknown physical parameters: The ice rheology and the friction coefficient. The known physical quantity is the surface velocity of the glacier. We show that an optimal ice rheology and an optimal friction coefficient exist. Further, we prove Gâteaux differentiability of the control-to-state operator. Finally, we prove the existence and uniqueness of a solution for the adjoint equations
Combined Effect of Melatonin and Sulfur on Alleviating Waterlogging Stress in Rapeseed
Get PDFMelatonin, a multifunctional, non-toxic regulatory molecule, plays a crucial role in enhancing tolerance to abiotic stress, which is tightly linked to S metabolism. Despite the proven efficacy of sulfur (S) in enhancing abiotic stress tolerance, the combined effect of S and melatonin in stress mitigation remains to be elucidated. This is particularly relevant in the context of climate change, where the increased occurrence of waterlogging stress increases the risk of reduced S availability, leading to reduced yield and quality in rapeseed. The objective of this study is to examine the impact of a combination of foliar melatonin and sulfur, when administered to soil or leaves, on the response of plants to waterlogging stress. The experimental design involved the supplementation of rapeseed (Brassica napus L.) plants with sulfur (S) to either the soil (0.2 g kg-1) or the leaves (300 ppm) 5 days prior to stress induction. The plants were subjected to waterlogging at BBCH-31 for a period of 7 days, preceded by a pretreatment 2 days prior to the stress with melatonin (200 μM). [...] However, the application of melatonin significantly mitigated the adverse effects of waterlogging stress. In comparison with the control, soil-S application exhibited higher efficacy than foliar S application in increasing plant resistance, as reflected by improved dry weight (+50%), photosynthesis (+12%), stomatal conductance (+40%), sulfur (+40%), magnesium (+59%), and reduced hydrogen peroxide (-22%) and lipid peroxidase (-26%). This combination also increased antioxidant defense by increasing catalase (+43%), glutathione reductase (+17%), ascorbate peroxidase (+47%), ascorbate (+39%), and glutathione (+40%) contents, in contrast to untreated waterlogged plants. The study underlines the potential of melatonin and sulfur as effective agents to alleviate waterlogging stress
Waterlogging Does Not Have a Lasting Impact on Yield Performance and Micronutrient Status of Oat (Avena sativa)
Get PDFWaterlogging increasingly threatens global crop production, particularly affecting major crops like wheat, barley, and maize at all growth stages. Although research on oat tolerance to waterlogging is limited, there is evidence that oat may be a suitable alternative crop due to its resilience and ability to maintain yields despite nutrient imbalances caused by waterlogging. However, it remains uncertain how oat responds to changes in soil micronutrient availability during periods of waterlogging. Therefore, this study aims to investigate whether (1) micronutrient toxicities or deficiencies are induced during waterlogging, (2) the timing of the flooding event is relevant for the expression of a possible nutrient imbalance, and (3) micronutrient toxicities/deficiencies affect yield performance. In order not to exclude possible varietal differences, three oat varieties were grown in large-scale containers and exposed to 14 days of waterlogging at either BBCH 31 or BBCH 51. Although early but not late waterlogging was effective in reducing dry weights, especially in white oat, yield performance, as reflected by the harvest index, was not affected at all. While early waterlogging increased Mn and Fe concentrations in all oat varieties, they were well below toxic level. In contrast, Cu concentrations in white oat dropped below the deficiency threshold levels. Zinc status, however, remained completely unaffected in all oat varieties. [...] It can therefore be assumed that at least the oat varieties tested have a high regeneration potential and also show a high tolerance to transient micronutrient imbalances
In situ monitoring of ligand-to-metal energy transfer in combination with synchrotron-based X-ray diffraction methods to elucidate the synthesis mechanism and structural evolution of lanthanide complexes
Get PDFDespite wide application of lanthanide complexes in solar cells, light-emitting diodes and sensors, their crystallization mechanisms have not been studied in detail. Further investigations of this kind can lead to the development of targeted synthesis protocols and tailoring of their structure-related physical properties. In this work, the structural evolution during the synthesis of the luminescent [Tb (bipy)2(NO3)3] (bipy = 2,2'-bipyridine) complex is studied by monitoring the ligand-to-metal energy transfer through in situ luminescence measurements combined with synchrotron-based X-ray diffraction (XRD) analysis. These experiments reveal an interesting crystallization pathway involving the formation of a reaction intermediate that is dependent on parameters such as ligand-to-metal molar ratios. In addition, the structure of [Tb (bipy)2(NO3)3] is solved from serial crystallography data collected at a microfocused synchrotron X-ray beamline. This is an emerging technique that can be used to interrogate individual crystallites and overcome beam damage effects. The resulting structure is found to correspond to that determined by classical single crystal XRD, and a perspective on realizing future in situ measurements of this type is given. This work therefore describes multiple advancements combining crystallite-specific diffraction probes and in situ techniques to track the synthesis kinetics of luminescent materials