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In past digital health interventions, an issue has been that participants drop out over time which is referred to as the ”law of attrition” (Eysenbach, 2005). Based on this, we propose that though initially, participants respond to the intervention, there is a hypothesized second diminishing e↵ect of an intervention. However, we suggest that on top, there is a third e↵ect. Independent of the individual notification or nudge, people could build the knowledge, skills and practice needed to independently engage in the behavior themselves (schraefel and Hekler, 2020). Using behavioral theory and inspired by prior animal computational models of behavior, we propose a dynamical computational model to allow for a separation of intervention and internalization. It is targeted towards the specific case of the HeartSteps intervention that could not explain a diminishing immediate effect of the intervention, second hypothesized e↵ect, while a person’s overall steps remained constant, third e↵ect (Klasnja et al., 2019). We incorporate a habituation mechanism from learning theory that can account for the immediate diminishing e↵ect. At the same time, a reinforcement mechanism allows participants to internalize the message and engage in behavior independently. The simulation shows the importance of a participant’s responsiveness to the intervention and a sufficient recovery period after each notification. To estimate the model, we use data from the HeartSteps intervention (Klasnja et al., 2019; Liao et al., 2020), a just-in-time adaptive intervention that sent two to five walking suggestions per day. We run a Bayesian estimation with Stan in R. Additional validation tests are needed to estimate the accuracy of the model for di↵erent individuals. It could however serve as a template for future just-intime adaptive interventions due to its generic structure. In addition, this model is of high practical relevance as its derived dynamics can be used to improve future walking suggestions and ultimately optimize notification-based digital health interventions.

The computational analysis and the optimization of transport and mixing processes in fluid flows are of ongoing scientific interest. Transfer operator methods are powerful tools for the study of these processes in dynamical systems. The focus in this context has been mostly on closed dynamical systems and the main applications have been geophysical flows. In this thesis, we consider transport and mixing in closed flow systems and in open flow systems that mimic technical mixing devices. Via transfer operator methods, we study the coherent behavior in closed example systems including a turbulent Rayleigh-Bénard convection flow and consider the finite-time mixing of two fluids. We extend the transfer operator framework to specific open flows. In particular, we study time-periodic open flow systems with constant inflow and outflow of fluid particles and consider several example systems. In this case, the transfer operator is represented by a transition matrix of a time-homogeneous absorbing Markov chain restricted to finite transient states. The chaotic saddle and its stable and unstable manifolds organize the transport processes in open systems. We extract these structures directly from leading eigenvectors of the transition matrix. For a constant source of two fluids in different colors, the mass distribution in the mixer and its outlet region converges to an invariant mixing pattern. In parameter studies, we quantify the degree of mixing of the resulting patterns by several mixing measures. More recently, network-based methods that construct graphs on trajectories of fluid particles have been developed to study coherent behavior in fluid flow. We use a method based on diffusion maps to extract organizing structures in open example systems directly from trajectories of fluid particles and extend this method to describe the mixing of two types of fluids.

In this framework the editor describes the intention, background and structure of the publication "Community Supported Economy - CSX - New entrepreneurial narratives in words, deeds, and pictures". In addition, this chapter introduces the readers to the concept of community-supported economy (CSX) and opens the space for their own reflection.

The concept of CSX allows us to envision how the idea of collaborative problem-solving and non-competitive change-making could be brought to life. The participation at the CSX meets Lüneburg event fueled the vision to find out more about how the CSX framework could be transferable and applicable to the consulting industry and sustainability consulting in particular. The encouraging kick-off led to the research question of: “Can sustainability consulting better fulfill its purpose in a CSX context as opposed to the conventional way?” The aims connected to this research question were to determine the status quo of community-supported approaches in sustainability consulting and to increase the visibility of existing organisations. Goals were also to find out how community-based work can lead to fruitful results in sustainability consulting. This was ought to be done by assessing the embodiment of CSX aspects in existing examples from practice.

Climate change presents a major sustainability challenge to coastal social-ecological systems (SES). The integration of climate change adaptation into processes or structures for coastal governance, however, has been described as challenging. Resilience presents a suitable concept to approach this problem, as it facilitates bridging between the natural and social sciences, as well as between science and policy in an inter- and trans-disciplinary approach. The Intergovernmental Panel on Climate Change also makes use of the concept of resilience and confirms that recent literature increasingly suggests that transformative changes in SES are required to enhance their resilience to climate change. Yet, knowledge gaps still exist on how to enable effective coastal governance to enhance the climate resilience of coastal SES. To address this problem, the importance of actionable knowledge is growing in climate change adaptation, environmental governance, and broader sustainability research. Actionable knowledge refers to knowledge that contributes to solving societal problems and points to actions and processes of change. One way of generating actionable knowledge is the co-production of knowledge with societal stakeholders. Yet, knowledge gaps exist in what methods and approaches may contribute to generating actionable knowledge and what obstacles to knowledge co-production exist especially for early-career researchers (ECRs). This dissertation contributes to research on generating actionable knowledge for coastal governance to enhance the resilience of coastal SES to climate change. It does this by providing theoretical, methodological and empirical insights on three research questions (RQs), laid out in Chapter I. These are: 1) what is a more actionable concept for applying the concept of resilience in coastal governance?; 2) what methods and approaches are suitable to generate actionable knowledge for coastal governance?; and 3) what obstacles to knowledge co-production exist for ECRs and how can they be overcome? The RQs are addressed in five publications, each presenting one chapter of this dissertation. For answering RQ1, Chapter II applies a research synthesis to bring together common themes and challenges documented in resilience, climate change and environmental governance literature. For answering RQ2, in Chapter III-V different methods and approaches for generating actionable knowledge are proposed and tested using a case-study in the SES of Algoa Bay, South Africa. These include i) the analysis of stakeholder agency as an indicator of the ability of stakeholders to act in governance processes; ii) the application of a stakeholder analysis to gain an improved understanding of the current degree of knowledge exchange for climate change adaptation; and iii) the combination of a capital approach framework, and fuzzy cognitive mapping, which shed light on the governance performance for climate change adaptation and on leverage points that can enhance climate resilience. Finally, for answering RQ3, Chapter VI provides a perspective on the obstacles that especially ECRs face, and actions that are needed to create the conditions under which knowledge co-production processes can be successful. This is done by applying a multi-method approach combining an online survey and workshop targeted at ECRs in the marine sciences. Key findings suggest that system and transformative knowledge are particularly important when applying the concept of resilience in coastal governance to generate actionable knowledge. The different methods and approaches that are proposed and tested contribute to generating both system and transformative knowledge. Firstly, they provide an overview of the capacities of different stakeholders to act, shed light on current collaboration and knowledge exchange, and enable the identification of different governance processes for coastal governance and climate change adaptation (system knowledge). Secondly, results have implications for how to improve knowledge exchange and identify leverage points that can enhance overall governance performance, thus providing recommendations on actions and processes that can enhance climate resilience in the case-study area (transformative knowledge). It is also highlighted how knowledge co-production can contribute to generating system and transformative knowledge together with stakeholders, and what actions are needed to build the capacities to translate knowledge into action. Additionally, the findings of this dissertation put forward actions that are needed at different organisational levels of the academic system to facilitate knowledge co-production processes with stakeholders involved in coastal governance. The results of this dissertation have implications for stakeholders and decision-making in the case-study area, as well as for environmental governance, climate change adaptation and broader sustainability research. Implications for stakeholders include recommendations for implementing formal commitments to share climate information across levels and sectors, establishing the role of information providers in the municipality, and reinforcing human capital within the local municipality in Algoa Bay. It also requires more support from the provincial government, such as addressing funding issues, offering training focusing on stakeholders with lower agency and capacities, and improving the overall availability and accessibility of climate information, as well as the priority given to climate change in the Integrated Development Plan. Findings also suggest the need for a more integrated approach to climate change adaptation in coastal planning and management frameworks. It also suggests that the conservation of environmental assets presents an important bottleneck for resilience management and needs to be further prioritised within decision-making. Implications for research include the applicability of methods beyond the context of this dissertation; a more actionable concept for approaching resilience in (coastal) governance systems that can be applied for achieving broader sustainability goals; and a more critical reflection on how transformative research is conducted, and what academic foundation is needed so that it can fulfil its societal goal. Future research may include a combination of the methods applied in this dissertation; qualitative applications of the stakeholder network analysis; and an application of the proposed approach to other case-studies using real-world laboratories. Overall, this dissertation provides theoretical, methodological, and empirical implications and insights into pressing SES problems. It also contributes to advancing the field of transformative research for more societally relevant outcomes in face of climate change and broader sustainability challenges

Stretching is primarily used to improve flexibility, decrease stiffness of the muscle- tendon unit or reduce risk of injury. However, previous animal studies from 1970 to 1990 showed significant hypertrophy effects in skeletal muscle in response to chronic stretching intervention with stretching durations of 30 minutes to 24 hours per day. However, no study in humans was performed using comparatively long stretching durations of more than 30 minutes per day with a daily frequency. The present cumulative dissertation includes six studies aiming to investigate the effects of long-lasting static stretching training on maximum strength capacity, hypertrophy and flexibility in the skeletal muscle. Before starting own experimental studies, a meta-analysis of available animal research was conducted to analyze the potential of long-lasting stretching interventions on muscle mass and maximum strength. To induce long-lasting stretching on the plantar flexors and to improve standardization of the stretch training by quantifying the angle in the ankle joint while stretching, a calf muscle stretching orthosis was developed. In the following experimental studies, the orthosis was used to induce daily long- lasting static stretching stimuli with different stretching durations and intensities in the plantar flexors to assess different morphological and functional parameters. For this, a total of 311 participants were included in the studies and, dependent on the investigation, the effects of daily stretching for 10-120 minutes for six weeks were analyzed. Therefore, effects on maximal isometric and dynamic strength as well as flexibility of the plantar flexors were investigated with extended and flexed knee joint. The investigation of morphological parameters of the calf muscle was performed by determining the muscle thickness and the pennation angle by using sonographic imaging and the muscle cross-sectional area by using a 3 Tesla magnetic resonance imaging measurement. In animals, the included systematic review with meta-analysis revealed increases in muscle mass with large effect size (d = 8.51, p < 0.001), muscle cross-sectional area (d = 7.91, p < 0.001), fiber cross-sectional area (d = 5.81, p < 0.001), fiber length (d = 7.86, p < 0.001) and fiber number (d = 4.62, p < 0.001). The thereafter performed experimental studies from our laboratory showed a range of trivial to large increases in maximum strength of 4.84% to 22.9% with d = 0.2 to 1.17 and ROM of 6.07% to 27.3% with d = 0.16 to 0.87 dependent on stretching time, training level and testing procedure. Furthermore, significant moderate to large magnitude hypertrophy effects of 7.29 to 15.3% with d = 0.53 to 0.84 in muscle thickness and trivial to small increases of 5.68% and 8.82% (d = 0.16 to 0.3) in muscle crosssectional area were demonstrated. The results are discussed based on physiological parameters from animal studies and in the front of knowledge in resistance training, suggesting mechanical tension to be one important factor to induce muscle hypertrophy and maximal strength increases. Further explanatory approaches such as hypoxia and changes in the muscle tendon unit are debated in the following. Since these studies are the first investigations on long-lasting stretch-mediated hypertrophy in humans, further research is needed to explore the underlying mechanisms and confirm the results in different populations to enhance the practical applicability for example in clinical populations when, e.g. counteracting muscular imbalances or sarcopenia in the elderly.

Mit der Digitalisierung geht eine Entgrenzung der Öffentlichkeit einher. Medientechnologien stellen nicht nur Möglichkeitsräume bereit, in denen Konflikte verhandelt werden. Sie transformieren auch den politischen Diskurs. Vor allem »die sozialen Medien« werden oft als Bedrohung einer konstruktiven Debattenkultur betrachtet. Die Beiträger*innen treten einen Schritt zurück und fragen aus sozial-, kulturwissenschaftlicher und philosophischer Perspektive, wie Öffentlichkeiten hergestellt und transformiert werden. Sie erörtern theoretische sowie empirische Perspektiven und analysieren normative Fragestellungen, die angesichts globaler Dynamiken und neuer Formen von Kulturkonflikten an Bedeutung gewinnen.

Angststörungen gehören im Kindes- und Jugendalter zu den häufigsten psychischen Störungen. Sie führen zu mittel- und langfristigen psychosozialen individuellen und gesellschaftlichen Beeinträchtigungen und Belastungen, sind entwicklungspsychopathologisch verbunden mit Defiziten in der Emotionsregulation, zeigen eine hohe Komorbidität mit anderen psychischen Störungen wie insbesondere mit depressiven Störungen und weisen zudem eine hohe Rezidiv- und Persistenzneigung sowie eine niedrige Remissionswahrscheinlichkeit auf. Auf dieser Grundlage kommt der Prävention von Angststörungen bei Kindern und Jugendlichen eine besondere Bedeutung zu. Aufgrund eines konstatierten Forschungsdefizits im Zusammenhang mit universeller Angstprävention im Kindes- und Jugendalter ist im Kontext dieser Dissertation das Trainingsprogramm „Super Skills for Life“ von Essau & Ollendick evaluiert worden. Dabei ging es insbesondere um die Überprüfung eines Treatment-Effektes. Das „Super Skills for Life“-Programm ist ein CBT-geführtes Modell, das neben Exposition auch Methoden der Entspannungstherapie und des sozialen Kompetenztrainings impliziert. Als Resilienzaufbauprogramm zeichnet es sich besonders durch die Anwendung der Videofeedbackmethode aus. Im Kontext der schulbasierten Evaluation wurde eine zweifaktorielle Varianzanalyse mit Messwiederholung (Follow-Up-Messung nach sechs Monaten) unter Einbezug von Kovariaten (Bildung, Klassenstufe und Familienstand) und zusätzlich unter Berücksichtigung von Post hoc-Tests (Geschlecht) durchgeführt. Innerhalb der Stichprobe von Grundschulkindern nahmen an der Interventionsgruppe n=77 und an der Kontrollgruppe n=87 Probanden teil. Im Ergebnis konnten in der Zusammenfassung im Wesentlichen keine ausreichenden signifikanten Effekte des Programms hervorgebracht werden, somit konnte kein Treatment-Effekt belegt werden. Abschließend für diese Dissertation wurden Limitationen dieser empirischen Untersuchung wie bspw. die fehlende Randomisierung, der geringe Stichprobenumfang und der einschränkende Regionalitätsbezug diskutiert.

Die Einführung von Industrie 4.0 und der damit verbundene Wandel des Produktionsumfeldes führen zu neuen Herausforderungen, bieten auf der anderen Seite aber auch neue Möglichkeiten für Unternehmen. Ausgehend von den Herausforderungen der Produktionsplanung und Steuerung als zentrales Element der Produktherstellung, z.B. Komplexität, Dynamik und neue Organisationsformen, werden bestehenden Methoden der Reihenfolgeplanung auf ihre Tauglichkeit zur Verwendung hin geprüft. Die Analyse zeigt, dass Aspekte wie die Ableitung von Handlungen und der Transfer von Wissen in unbekannten Situationen zu den größten Herausforderungen für bestehende Verfahren zählen. Die in der Arbeit neu entwickelte Methode zur dynamischen Auswahl und Anpassung von Reihenfolgeregeln in komplexen Fertigungssystemen mit bestärkendem Lernen greift diese Herausforderungen auf und untersucht mögliche Lösungsstrategien. Die im Rahmen der Arbeit neu entwickelte Methode wird über ein Spektrum an unterschiedlichsten Szenarien evaluiert und mit anderen Methoden verglichen. Dabei werden verschiedene Ausprägungen und Komplexitäts-Niveaus von Handlungen, der Beobachtungsraum und die Mengen an benötigten Daten detailliert analysiert. Schlussendlich zeigt sich, dass die neue Methode in der Lage ist, die Anforderungen an die Produktionsplanung- und Steuerung zu erfüllen und in bekannten wie in unbekannten Szenarien gut Leistung zu erbringen. Zusätzlich ist die Methode in der Lage menschenähnliche Leistungen zu bringen und kann in einem realen Anwendungsfall zur Unterstützung der Produktionsplanung und -Steuerung genutzt werden.

Kinder werden häufig vor Fremden gewarnt, die sie auf dem Nachhauseweg ansprechen. Doch wie steht es um Fremde, die sich im Netz hinter dem Profil eines Kindes verstecken? Vor dem Hintergrund steigender Fälle von Cybergrooming war es Ziel dieser Pilotstudie, eine Bestandsaufnahme über das Vertrauen von Kindern der dritten und sechsten Klasse in „gleichaltrige“ Fremde im Internet zu geben. Darüber hinaus gewährt die Studie Einblicke in Erfahrungen, die Kinder mit Fake-Profilen, sprich Profilen mit unwahren Identitätsinformationen, gemacht haben. Der Versuchsaufbau folgte einem 2 x 2-faktoriellen quasiexperimentellen Design mit dem Zwischensubjektfaktor „Alter“ (3. Klasse vs. 6. Klasse) und dem Innersubjektfaktor „Ort des Kontakts“ (offline vs. online). Die Stichprobe bildeten 58 Schüler:innen der dritten (n = 31) und sechsten Klasse (n = 27). Es wurde ein Fragebogen genutzt, der die Bewertung der Vertrauenswürdigkeit der Fremden, das Vertrauen in deren Identitätsinformationen sowie Erfahrungen mit Fake-Profilen erfasste. Die Ergebnisse zeigen, dass Kinder Fremde online als signifikant weniger vertrauenswürdig einschätzen im Vergleich zu Fremden offline. Darüber hinaus vertrauten dem Online-Fremden die älteren Sechstklässler:innen signifikant weniger als die Drittklässler:innen. Fast jedes zweite Kind gab Erfahrung mit Fake-Profilen an, jedoch wurden nur wenige geeignete Erkennungsmerkmale für diese genannt. Aus den Ergebnissen lässt sich ableiten, dass Kinder bereits um die Gefahr von Fake-Profilen wissen, allerdings scheinen sie teilweise ratlos zu sein, wenn es um deren Erkennung geht. Die Studie bietet einige Ansatzpunkte für zukünftige Forschung, die zum Abschluss diskutiert werden.