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Kooperation an der Schnittstelle von Kinder- und Jugendhilfe und Kinder- und Jugendpsychiatrie-Studien zur Wahrnehmung von Fachkräften
No full textInterprofessionelle Kooperation wird von Fachkräften häufig als eine bereichernde und wirksame Arbeitsform wahrgenommen, die neben einer besseren Versorgung von Klient:innen mit einem geschärften Bewusstsein für die eigenen professionsspezifischen Kompetenzen und mehr gegenseitigem Verständnis unter den Berufsgruppen einhergeht. Aushandlungen und Absprachen mit anderen Professionen können jedoch auch ein gesteigertes Arbeitsvolumen, eine Einbuße an professioneller Autonomie, Konflikte implizieren, mit einer höheren Arbeitsbelastung, ineffektiveren Arbeitsprozessen und Fehlern verbunden sein. Vor diesem Hintergrund ist Kooperation kein Patentrezept, sondern ein komplexe Prozess, der Spannungen erzeugen, scheitern und Unsicherheiten für die Beteiligten umfassen kann. Die vorliegende Dissertation bietet einen sozialpsychologischen Erklärungsansatz dafür, dass Kooperation für Fachkräfte sowohl Entlastung als auch Belastung bedeuten kann. Den Kern der Arbeit bilden drei Publikationen zu empirischen Studien des spezifischen Kooperationsverhältnisses zwischen der Kinder- und Jugendhilfe und der Kinder- und Jugendpsychiatrie aus. In zwei Veröffentlichungen werden Messinstrumente einer psychometrischen Güteüberprüfung unterzogen und die Dimensionen der Kooperationsqualität geschärft. Die deutsche Version des PINCOM-Q (G) erhebt die Wahrnehmung von Fachkräften in Bezug auf die allgemeine Prozessqualität der Kooperation an der Schnittstelle der beiden Systeme. Der zweite Fragebogen wurde eigens im Rahmen eines Forschungsprojektes zur Verbesserung der Kooperation zwischen Kinder- und Jugendhilfe und Kinder- und Jugendpsychiatrie entwickelt und misst, wie Fachkräfte die Zusammenarbeit in der Versorgung von komplex psychisch belasteten Kindern und Jugendlichen mit umfangreichem Jugendhilfebedarf wahrnehmen. Die dritte Publikation präsentiert Ergebnisse einer Fragebogenerhebung unter Fachkräften in Jugendämtern, in der Heimerziehung und in kinder- und jugendpsychiatrischen Kliniken. Die Ergebnisse zeigen, dass beide Skalen Differenzen in der Wahrnehmung sowohl auf der Ebene der Berufsrolle als auch der organisationalen Zugehörigkeit sichtbar machen können. Es werden Handlungsempfehlungen abgeleitet, wie die Messinstrumente in Forschung und Praxis eingesetzt werden können, um das Potenzial von Kooperation in diesem Feld besser auszuschöpfen
Experimental Evidence on Individual and Collective Decision-Making in Ethical Dilemmas and Unfair Contests
No full textAufsätze über zeitbasierte Entscheidungsfindung und die Leistung von Losgrößenheuristiken
No full textThe productive use of managerial time and the timing of investments present success factors for companies. The popular time management literature recommends investing time now to save time later (e.g., the 5S concept). In finance, early investing is recommended, too, as returns of investments accumulate over time. Managers are often faced with the decision of whether to invest time in a particular task or pay for its completion. In many economic approaches, time is set equal to money, since these are exchangeable via labor wages. However, time is perceived differently than money. In particular, time is perceived to be more ambiguous and less easily fungible than money.
Although past investments in a project are irrelevant to deciding whether to invest in the project in the future or not, the occurrence of past investments often influences investment behavior. The tendency to continue with a project when money, effort, or time has already been invested is termed the sunk cost effect and can lead to escalating commitment. The sunk cost effect has been demonstrated in various contexts. However, the results of previous research on the consideration of past investments are inconsistent.
In addition to investing time and money, lot sizing represents another topic of operations management and this dissertation. Modern ERP systems allow demand to be forecasted for short time periods. The daily instead of weekly representation impacts demand patterns. Weekly demand may contain only a few periods with zero demand, while periods with zero demand occur more frequently when demand is daily. Close-to-zero demand means that large demands occur at longer intervals, while relatively small demands occur on all other days. In many ERP systems, myopic lot-sizing heuristics like that of Silver & Meal (1973) and Groff (1979) are implemented. However, these heuristics do not perform well for irregular (daily) demand.
The dissertation “Essays on Time-based Decision Making and the Performance of Lot-sizing Heuristics” includes 3 research papers. The first two papers analyze how time versus money is invested in a dynamic situation and how time is invested after past time investments occur. In the first paper, we theoretically model and empirically investigate how time versus money is invested in dynamic decision-making situations. In the considered resource allocation problems, early investments are favorable because returns on investments accumulate over time. It is optimal to invest (time/money) and harvest rewards later. However, individuals fail to invest first and harvest later. The central finding is that the timing of investments improves when time investments meet monetary rewards. In these cases, it appears that simple myopic rules do not impose, and cognitive reflection sets in.
Paper 2 investigates the effect of the occurrence of past unsuccessful investments. We examine the classical sunk cost situation, where a choice can be made between the sunk cost project and a superior alternative, and the situation where the sunk cost project is the superior project. We analyze whether individuals abandon a project they have unsuccessfully invested time. In the setting considered, without responsibility for past unsuccessful investments, decision makers leave the project with sunk time investments – even if the project is superior.
In paper 3, we compare ten lot-sizing heuristics, including well-known simple myopic heuristics like that of Silver & Meal (1973) and Groff (1979), in a rolling horizon environment and find that over all demand patterns and types, the Wagner-Whitin-Look-Beyond algorithm has shown the least mean relative additional costs (0.103 %). The next best heuristic is the combination heuristic K-Gr-zero that consists of the Groff-zero heuristic and an iteratively applied improvement step, in which replenishment points are shifted forward or backward a few periods (mean relative additional costs of 0.87 %)
Numerically Exact Simulation of Non-Markovian Open Quantum Dynamics
No full textThis thesis focuses on the numerically exact computation of the nonequilibrium quantum dynamics of several instances of the Caldeira-Leggett model. It begins with a detailed derivation of the quasi adiabatic propagator path integral method, along with a minor improvement of the original iteration scheme. Additionally, the small matrix decomposition of the path integral expression is derived, and the approximation it introduces is systematically analyzed. Next, an introduction to the tensor network formalism is provided, followed by a derivation of the time-evolving matrix product operator (TEMPO) technique that is significantly simpler than what is given in the original literature. TEMPO is benchmarked on a trivially solvable model, revealing its quadratic computational complexity with respect to the inverse discretized time step. By utilizing TEMPO, a novel dynamical phase of the (sub-)Ohmic spin-boson model at zero temperature is discovered, and a corresponding phase diagram is obtained. Furthermore, the dephasing rate at weak system-bath coupling in the (sub-)Ohmic and the 1/ f regime is studied. The TEMPO method is then generalized to the case of multiple baths acting on the central system, and subsequently used to study the disruption of the quantum Zeno effect in the Ohmic spin-boson model. Finally, the hierarchical equations of motion technique is summarized and used to demonstrate that a spectroscopic technique known as transient redistribution of ultrafast electronic coherences in attosecond Raman signals is robust against environmental dissipation at room temperature.Diese Arbeit beschäftigt sich mit der numerisch exakten Berechnung verschiedener Instanzen des Caldeira-Leggett-Modells. Sie beginnt mit einer detaillierten Herleitung des quasiadiabatischen Propagator-Pfadintegrals (QUAPI) und einer geringfügigen Verbesserung des ursprünglichen Iterationsschemas. Darüber hinaus wird die kleine Matrixzerlegung des Pfadintegralausdrucks (SMatPI) hergeleitet und die dadurch eingeführte Näherung systematisch analysiert.
Daraufhin wird der Tensornetzwerk-Formalismus eingeführt, gefolgt von einer Herleitung des zeitlich sich entwickelnden Matrixproduktoperators (TEMPO), die wesentlich einfacher ist als die in der ursprünglichen Literatur beschriebene. TEMPO wird an einem trivial lösbaren Modell getestet, wobei gezeigt wird, dass dessen Rechenkomplexität quadratisch im inversen diskretisierten Zeitschritt ist.
Durch den Einsatz von TEMPO wird eine neue dynamische Phase des (sub-)ohmschen Spin-Bosonen-Modells bei Nulltemperatur entdeckt und ein entsprechendes Phasendiagramm erhalten. Außerdem wird die Dephasierungsrate bei schwacher System-Bad-Kopplung im (sub-)Ohmschen und im -Regime untersucht. Die TEMPO-Methode wird dann auf den Fall verallgemeinert, dass mehrere Bäder auf das zentrale System einwirken, und anschließend verwendet, um die Störung des Quanten-Zeno-Effekts im Ohmschen Spin-Boson-Modell zu untersuchen.
Schließlich wird die Methode der hierarchischen Bewegungsgleichungen (HEOM) zusammengefasst und angewandt, um zu demonstrieren, dass eine spektroskopische Technik, die als transiente Umverteilung ultraschneller elektronischer Kohärenzen in Attosekunden-Raman-Signalen bekannt ist, bei Raumtemperatur robust gegenüber Störungen durch die Umgebung ist
Creating degenerate two-dimensional Bose gases with tunable interaction strength
No full textThis thesis describes the experimental realisation of versatile and highly controllable quantum systems with ultracold quantum gases with the aim to study quantum many-body physics.
In the first part we present the implementation of mesoscopic Fermi-Hubbard-type systems with potassium-40 in a bottom-up approach employing optical tweezers. The experimental setup features an in-vacuo microscope objective with a numerical aperture of 0.75 enabling high-resolution imaging, and allows for tunable interaction strengths via Feshbach resonances as well as for rapid repetition rates due to all-optical cooling schemes. However, reaching quantum degeneracy via Raman-sideband cooling turned out to be very challenging. The achieved 3D ground state fractions of ∼40% is not sufficient to make the study of quantum physics in the Hubbard model feasible.
In the main part of the thesis we discuss how the experimental setup was re-designed and re-built in order to create two-dimensional bosonic bulk systems with potassium-39. The key feature is the rare combination of highly tunable interaction strengths via a variety of intra- as well as interstate Feshbach resonances with the ability to study spin mixtures with high-resolution imaging. We have been able to realise a three-dimensional quasi-pure Bose-Einstein condensate of ∼5 · 10^3 atoms. The sample is then brought into the quasi-two-dimensional regime by first pre-shaping it with a light sheet-like trap and then transferring it into a single layer of a blue-detuned optical lattice. As a result a degenerate two-dimensional Bose gas of ∼3 · 10^3 atoms with a temperature of ∼50nK corresponding to ∼0.2 T_{BKT} is created, where T_{BKT} is the BKT critical temperature. Finally, we discuss how 2D quantum droplets might be realised with the setup
Analysis of the viral evolution of zoonotic RNA viruses in their natural host
No full textLassa virus (LASV) can cause Lassa fever (LF), a severe febrile illness which is responsible for 900,000 infections and 18,000 deaths annually. LASV is a the negative-sense RNA virus, which belongs to the family of Arenaviridae, and is a zoonotic pathogen. Transmission of LASV to humans occurs through the body fluids and excretions of its primary rodent reservoir, Mastomys natalensis. Recent findings indicate that additional rodent species also carry LASV and infection and transmission experiments involving different LASV strains in M. natalensis revealed previously that strains originating from M. natalensis (homologous strains) establish persistent infections, while those from other sources (heterologous strains) are cleared rapidly. The objective of this project was to pinpoint viral factors that limit the host range of LASV. To achieve this, an in vitro system with M. natalensis cells was established in the beginning of this project and characterized regarding the expression of receptors required for LASV cell entry and the release of infectious progeny viruses. This system allowed to study host barriers in vitro and thus reduced the number of animals used during these studies significantly. The growth kinetics of LASV strains originating from different rodents were assessed on two cell lines derived from M. natalensis, namely Mastomys kidney epithelial cells (MasKEC) and Mastomys embryonal fibroblasts (MasEF). The growth of the heterologous Kak428 strain was attenuated compared to the Mastomys-derived Ba366 strain. As these growth kinetics resembled the growth of previous in vivo experiments, the next step was to assess the role of each viral protein on the virus-host barrier. Therefore, chimeric viruses were generated and used both for in vitro and in vivo experiments. When the glycoprotein (GP), L protein (L) or nucleoprotein (NP) of a heterologous strain was inserted into the genetic background of a homologous strain, the growth was strongly impaired, and the virus was cleared rapidly from the animals. The strains exhibiting attenuated growth on MasKEC cells were further characterized. Serial in vitro infection experiments on MasKEC were employed to adapt the heterologous LASV strain to Mastomys natalensis, and potential host-adaptive mutations were identified by Next Generation Sequencing. Following serial passaging on MasKEC, rapid adaptation occurred, resulting in accelerated replication and elevated peak titers for the heterologous strain. The mutations occurring during this process were accumulating in the GP, L and NP genes and mapped to their respective 3D protein structures. Additionally, some virus variants after ten passages of adaptation in cell culture, were used for in vivo experiments and revealed varying levels of adaptation.
By using virus-life cycle modelling systems, the different life cycle steps were elucidated further. During entry, an impairment of the heterologous strain was noted and in replicon assays to assess the replication and transcription, the NP of this strain seemed to be more restricting than the L protein. The latter assay was also used to characterize the NP mutations identified during the adaptation experiments further.
In summary, an in vitro model for LASV infection of natural host cells was established, and it closely mirrors the in vivo observations. Moreover, LASV demonstrated the ability to adapt to new host cells quickly, and potential host-adaptive mutations within the virus genome were characterized in replicon assays, entry assays and in in vivo experiments
All Three AKT Isoforms Can Upregulate Oxygen Metabolism and Lactate Production in Human Hepatocellular Carcinoma Cell Lines
No full textEssays on Adaptation and Behavioural Responses to Abrupt Changes
No full textHumanity is currently facing a range of interconnected socio-ecological challenges, including climate change, economic instability, social crises, and pandemics. These issues often lead to abrupt changes, demanding the development of effective adaptation mechanisms to mitigate their impacts, particularly when they threat human survival. Hence, it is important to improve the understanding of adaptation, and identify the mechanisms driven its process. This thesis aims to advance the knowledge in this area by developing methodologies for assessment and exploring the influence of culture and risk preferences on the adaptation process.
Chapter 2 introduces an analytical framework to assess adaptation. This framework develops a metric to assess adaptation in a coupled human-ecological system. It derives driver-specific adaptation responses and disentangles the concepts of adaptation, sensitivity and total impact. The framework is applied to a calibrated bio-economic model focusing on the North Sea flatfish fishery. The case study demonstrates how fishers adapt through effort to three different changes in drivers and illustrates their differentiated effects on quantities supplied in the market.
Chapter 3 adopts an interdisciplinary approach to assess adaptation, using the conceptual representation of a socio-ecological system and the Ostrom Framework. The case study examines German flatfish fisheries and identifies the strategies they employed to persist despite the numerous challenges they encounter. Among the strategies, cultural traditions and self-identification as a fisher, rather than an entrepreneur, play and important role to foster adaptation.
Recognizing the importance of culture in adaptation, chapter 4 examines the role of cultural heritage from a consumer perspective. This chapter 4 focuses on the German brown shrimp fishery, the most important coastal fishery in Germany. Using a discrete choice experiment, this chapter estimates the willingness to pay of tourists and locals to preserve the cultural heritage of the shrimp fishery. The target population is drawn from four towns in Germany -Ditzum, Busum, Cuxhaven, and Gretsiel- recognized for preserving the traditional practices. The findings reveal that individuals in these areas
value maritime cultural heritage, along with other attributes of this fishery, such as its environmental sustainability.
The final chapter explores the role of risk preferences on the adaptation process, focusing on the post-impact phase following an abrupt change. Using the 2023 Turkey earthquake as a case study, this chapter investigates how individual risk preferences shift in response to the disaster. Through a combination of surveys and lab-in-the-field experiments involving over 600 participants - including both survivors of the earthquake and residents of unaffected cities in Turkey - the study reveals that individuals heavily impacted by the earthquake tend to become more risk-tolerant, with gender and damage level as significant factors influencing their responses.
In summary, this thesis investigates adaptation by integrating analytical and experimental methodologies. It develops metrics for assessing adaptation and examines the influence of culture and risk preferences on the adaptation process. By employing a variety of methodologies across different human-environment systems, this thesis contributes to a more comprehensive understanding of the complex and interdisciplinary nature of adaptation