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Item type: Item , Opening up food sovereignty and Community Supported Agriculture with organizational perspectives: zooming into the diversity of economic actors that are striving for food sovereignty(2025) Middendorf, MatthiasAgri-food systems face multiple interlinked crises, including accelerating climate change, biodiversity loss, entrenched social inequalities, and pressures on democratic institutions. Food sovereignty has emerged as a prominent pathway for transforming agri-food systems toward greater justice and sustainability, understood as peoples’ right to healthy, culturally appropriate food produced sustainably and to define their own agri-food systems. It is articulated as both a social movement and an alternative food concept and is addressed in movement strategies, policy debates, and research at international, national, and regional levels. Yet most analyses remain concentrated at the macro-/system-level, while actors and organizational phenomena receive limited analytical attention. In particular, actors engaged in economic activities (e.g., production, processing, distribution) are not consistently named in the food sovereignty discourse as ‘economic actors’ and are often overlooked. This stands in tension with the movement’s explicit calls to build an alternative economic model. Shaped by critiques of the corporate agri-food system, such terminological caution fosters generalization and limits differentiation among actors, thereby sidelining analysis at the organizational level. As a result, the organizational configurations through which economic actors operate (understood as combinations of organizational characteristics such as decision-making, property, and labor) are seldom examined. This conceptual flattening marginalizes organizational perspectives in the food sovereignty discourse and underrepresents the diversity of economic actors, their configurations, and challenges, thereby limiting opportunities for their support. The functioning and stability of economic actors are essential for shaping transformations. Accordingly, organizational configurations must be analyzed alongside economic activities. Community Supported Agriculture (CSA) organizations, often cited as an expression of food sovereignty, illustrate this gap, as they are rarely differentiated or subjected to organizational analysis. The overall aim of this dissertation is to open up, broaden, and deepen the discourse on food sovereignty and CSA by approaching food sovereignty not only as a movement and concept but also as an organizational phenomenon. It uses organizational perspectives as a heuristic lens to render the organizational configurations of economic actors analytically visible. Adopting an actor-centered perspective at the organizational level, the dissertation conceptualizes the diversity of economic actors striving for food sovereignty (EAFS) and differentiates their organizational configurations in general and for CSAs in particular. The first paper develops a conceptual framework based on an integrative literature review and thematic analysis of 108 publications on food sovereignty, including gray literature. It conceptualizes organizational diversity within EAFS by identifying general patterns across Global North and Global South contexts and differentiates EAFS at the organizational level. The second transdisciplinary paper develops a CSA Framework in partnership with the German CSA Network and applies a mixed-methods design to CSAs in Germany. It uses a survey of 70 CSAs to test the framework, documents organizational heterogeneity, demonstrates that configurations differ by governance type (producer-led, consumer-led, integrated), and confirms the diversity and complexity of CSA organizations. Synthesizing the findings of both studies yields the Synthesized EAFS Framework, which provides a more differentiated organizational perspective on EAFS. This framework distinguishes three domains comprising 12 characteristics: Conditions that shape EAFS (Motives, Transformative approach, Intersectionality), Organizational-related characteristics (Organizational governance types, Founding impulse and establishing paths, Ownership/Property and legal forms, Work/Labor, Participation, Non-economic partnerships and cooperation), and Economic-related characteristics (Production practices and services, Scope of supply chains, Economic partnerships and cooperation). The framework defines Size as a cross-cutting structural factor. Conditions guide configuration choices across these characteristics. The framework also embeds the governance typology from the second study as a key lever for allocating decision rights. In doing so, the framework provides an actor-centered language for systematic comparison that moves beyond overly abstract descriptions. Finally, the dissertation aligns the Synthesized EAFS Framework with the six food sovereignty pillars established at the 1st Global Nyéléni Forum. This alignment makes configurations of EAFS at the organizational level analytically visible and grounds the framework in widely recognized movement principles. This supports the view that food sovereignty is also an organizational phenomenon and frames EAFS as a configuration space in which mixed forms are common. Accordingly, the findings reject simplistic binaries and show the prevalence of mixed forms: depending on the configuration, EAFS can combine conventional logics (e.g., market participation, revenue generation) with alternative approaches (e.g., solidarity-based practices, community ownership, collective governance, shared economic risk). This perspective centers on differentiated organizational configurations rather than generalized forms. Taken together, the dissertation makes several key contributions. Conceptually, it first makes the diversity of EAFS along the agri-food supply chain visible. Second, it develops an integrative, actor-centered organizational language and a novel framework that links food sovereignty goals to organizational phenomena and enables application across contexts as well as the analysis of EAFS configurations. Empirically, it documents organizational heterogeneity among CSAs in Germany, a prominent EAFS case, and shows how governance types and characteristics are distributed. Methodologically, it offers an analytical lens for comparing EAFS in different settings by making organizational configurations analytically visible. In practice, it guides context-sensitive configurations for practitioners and movement educators and supports alliance-building among EAFS. It enables the identification of organizational challenges (e.g., unclear decision rights and roles, resource constraints, power asymmetries) that provide a basis for strengthening organizational stability and adaptability. For policy and support systems, it points to the importance of aligning instruments with actual configuration options and addressing organizational challenges where relevant. Future research should refine and extend the Synthesized EAFS Framework beyond CSA to other EAFS (e.g., food hubs or food processing actors) and apply it across contexts, including in the Global South. It should examine decision-making, participation, and power within governance types to determine who benefits and who is excluded. It should also analyze how organizational stability and adaptability relate to governance and ownership/property under operational constraints. Overall, these directions shift the discourse from whether EAFS matter to how specific configurations function, for whom, and under what conditions, while supporting practice-research transfer within the contemporary food sovereignty discourse.Item type: Item , Mass spectrometric analysis of particulate matter in remote regions and highly polluted Chinese and Iranian megacities(2025) Barth, ChristofThe investigations in the present work are intended to contribute to the understanding of the health and environmental impacts of aerosol pollution, both in remote regions and in strongly polluted megacities. This was achieved by a combination of different instrumental and methodological approaches. First, in-situ single-particle analysis and its evaluation, based on multivariate statistical methods, was methodologically advanced using the example of a comparative measurement of standard samples in the laboratory and of online measurements on the Jungfraujoch high altitude research station at 3580 m asl in the Swiss Alps. In order to rationalize single-particle data, weather conditions, wind speed and wind direction as well as the geographical position during the measurement were taken into account. It was found that during the field measurements at the Jungfraujoch site, Sahara desert storm events were a major source for less aged iron- and silicon-rich mineral particles. Between those events the particle population was dominated by inorganic carbonaceous compounds. Both types of particles increase the local temperature and accelerate snowmelt, either by reducing snow albedo or by absorbing light over a broad spectral range. Secondly, in order to be able to address the environmental and health related factors in greater detail, particles from two heavily polluted megacities in Hangzhou, China and Tehran, Iran were extensively characterized. Filter samples were collected and measured by high-resolution mass spectrometry imaging to assign organic hydrocarbons and more complex inorganic compounds. This enabled analysis of intact organic molecules with high mass resolution and high mass accuracy. The novel methodological approach, in which the surface of particle quartz filter samples was scanned under atmospheric pressure using a 343 nm (Yb:YAG) laser (lateral resolution about 50 µm), enabled spatially resolved determination of the molecular particle composition. More than 3200 inorganic and organic compounds were specifically assigned to individual particles based on their exact mass and location on the filter surface. Particle sources could be easily distinguished from each other by means of characteristic mass spectrometric patterns using statistical clustering methods. Standard addition methods were also used to quantify polyaromatic hydrocarbons (PAHs) on the surface of the filters. By correlating the quantitative data with the spatially resolved particle measurements, it was possible to make well-founded statements about the respective particle pollution and its causes on site. Levels of heavy metals and harmful organic compounds, primarily from anthropogenic sources, were significant in both cities. However, higher concentrations of PAHs and a greater number of heavy metal compounds were found in the samples from Tehran. Since total particle pollution in Tehran during sampling was lower than in Hangzhou, these values are extremely alarming and demonstrate the non-compliance with and the lack of air pollution control strategies in the eastern Mediterranean region. Finally, it was shown that both methods require little or no sample preparation and provide excellent results in terms of speed, accuracy and selectivity.Item type: Item , Modelling temperature-dependent schistosomiasis dynamics for single and co-infections with S. mansoni and S. haematobium(2025) Tabo, Zadoki; Breuer, Lutz; Albrecht, ChristianSchistosomiasis, a prevalent public health issue specifically in sub-Saharan Africa, is primarily attributed to Schistosoma haematobium and Schistosoma mansoni, often occurring concurrently. These schistosome species share similarities in life cycles and transmission, manifesting comparable infection patterns and susceptibility to temperature variations. This study investigates the influence of temperature control not only on the transmission of individual species but also on their mutual interactions and co-infection dynamics using a mathematical model. Sub-models and co-dynamic properties, including reproduction numbers, equilibrium states, and stability conditions, are derived. Sensitivity analysis is performed to clarify the impact of parameter variations on model stability. Results suggest that temperature variation increases the spread of S. haematobium, which enhances susceptibility to S. mansoni co-infection, possibly by altering the immune response. At moderate temperatures (20°C and 25°C), infection levels in both single and co-infected individuals are higher, while recovery rates increase with temperature, peaking at 25°C and 35°C as infections significantly decrease. Biomphalaria snails exhibit greater population growth and susceptibility to infection than Bulinus snails, particularly below 25°C. Above this temperature, Biomphalaria population decreases while Bulinus species are more likely to experience faster mortality. These temperature-related variations differently impact mortality rates of intermediate snails and snail-to-human transmissibility rates for schistosome species, holding significant health implications. Targeting snails during seasons below 25°C, when susceptibility is higher, and intensifying human treatment interventions around 25°C–35°C, where recovery rates peak, may yield optimal results, particularly during seasons with intermediate temperatures around 25°C for both snails and humans. The results underscore the importance of integrating temperature into models for predicting and managing schistosomiasis dynamics for both genera. Therefore, this model is applicable not only to sub-Saharan Africa, but also to other regions where the described temperature ranges match with the local climate.Item type: Item , Exploring for gloss : active exploration in visual material perception(2025) Lin, Lisa P. Y.; Drewing, Knut; Dörschner-Boyaci, KatjaImage motion contributes to the perception of visual material properties, and motion signals are generated during active exploration. However, little is known about how specific perceptual tasks influence the actions that generate these cues. In an experiment using virtual reality and real-time hand tracking, we investigated how the demands of perceptual tasks (e.g., judging gloss or lightness) shape exploratory behaviors. Participants either observed or actively explored objects varying in gloss and lightness while performing a matching task. We analyzed how their exploration patterns varied based on the tasks. Using the same stimuli in both tasks, we found that participants explored objects more extensively when judging gloss than when judging lightness. These findings suggest a strategic prioritization of relevant cues for gloss judgments, with participants using larger movements and object rotation to enhance viewing perspectives and highlight detection. Our findings show that exploration behaviors are task dependent, with actions adapted to the demands of the perceptual task at hand.Item type: Item , Association of stress and inflammatory diseases with serum ferritin and iron concentrations in neonatal calves(2025) Sickinger, Marlene; Jörling, Jessica; Büttner, Kathrin; Roth, Joachim; Wehrend, AxelThis study investigated the effects of iron supplementation and inflammatory disease on cortisol, white blood cell (WBC) count, total protein (TP), lactate, interleukin 1 β (IL1β), interleukin 6 (IL6), substance P (SP), hepcidin, haptoglobin, and ferric-reducing ability of plasma (FRAP) in calves. Correlation analyses for the aforementioned parameters with serum iron and ferritin were performed in 40 neonatal calves over the first 10 days of life. Neither iron supplementation, disease status, nor sex had statistically significant effects on the areas under the curve of ferritin, WBC, TP, IL1β, IL6, SP, hepcidin, haptoglobin, or FRAP. However, cortisol concentrations were influenced by disease development. Cortisol concentrations were higher at birth (44.1 ± 1.95 ng/mL) than on day 2 (38.8 ± 1.87 ng/mL) (p = 0.0477), and healthy animals exhibited lower cortisol concentrations than diseased calves (p = 0.0028). Correlation analyses indicated weak positive correlations between ferritin and IL1β (p = 0.0015; ρ = 0.49) and IL6 (p = 0.0011; ρ = 0.50), respectively. The clinical significance of these findings and resulting therapeutic consequences, especially with respect to iron supplementation, should be further investigated in calves and adult cattle.