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Engineering a multivariate cobalt metal–organic framework for high photocatalytic activity: the impact of mixed ligands and metal incorporation in a visible light-driven heterogeneous photo-Fenton reaction for water treatment†
No full textMetal–organic frameworks (MOFs) have attracted increasing attention for the removal of organic pollutants in wastewater via photocatalysis. Here, we design a multivariate modification of ZIF-9 to tune its electronic properties for use in visible light photocatalysis. A controllable synthesis of ZIF-9 and its multivariate forms with the incorporation of copper and the 2-imidazolecarboxaldehyde (ica) ligand was carried out. The materials are tested for the removal of the model dye methylene blue (MB) by a heterogeneous photo-Fenton-like reaction at neutral pH and room temperature. Cu-ZIF-9-ica (UPO-3) shows high photocatalytic activity under both visible and ultraviolet A (UVA) light, achieving 94% MB degradation in 45 min, compared to 65% MB degradation in 120 min using bare ZIF-9. The study revealed a first-order rate constant of 0.0475 min −1 for Cu-ZIF-9-ica compared to 0.0088 min −1 for ZIF-9 under visible light. The improvement of the catalyst was clearly attributed to the co-incorporation of Cu and the ica ligand in the MOF, which reduces the band gap, in agreement with DFT calculations. Reproducibility and recyclability tests proved that Cu-ZIF-9-ica can be used for at least 3 cycles without a significant loss of efficiency, making it a promising material for the study and application of wastewater treatment.Peer Reviewe
Liminale Texte. Insights from the Edge
No full textThis contribution’s central thesis argues that some texts oscillate between social fields, such as sociology and literature, without ever being able to be fully assigned to one of these two fields. Liminal phases are characterized by their positioning between social fields and boundaries, they bring together the separated and mix the known in unknown ways. To this end, Victor Turner’s concept of liminality is applied to texts that oscillate between writing cultures in the sense of Susanne Knaller and Stephan Moebius. Liminality here means an existence between social fields, an existence in between spaces. Liminal texts assume the function of a bridge between the boundaries (Osterhammel) that separate social fields such as literature and sociology. They have an experiential character of their own and surprise the fields and social actors. After explaining the terms »liminality« according to Turner and »liminal texts« according to Knaller and Moebius, the article develops the phases of liminal texts as a theoretical concept. Therefore, I propose a concept of the production of liminal texts, which is divided into liminal actors and liminal phases. Liminal authors are characterized by their experience with the boundaries between social areas, classes and groups. In this way, they experience different belief systems and conceptual worlds, so-called doxa (Bourdieu), by touching social boundaries and crossing such boundaries. In this respect, liminal authors are characterized by a cleft habitus (Bourdieu), which depends on the experiences of different social worlds. In this way, they sometimes develop a precise sense of the multiple truths (doxa) and boundaries that exist between fields, classes, and thus between actors. Since these habitus are also partly the habitus of writing actors, it can be deduced from this how the diverse texts of social climbers, which creatively combine literature and science, subjectivity and objectivity, can also become liminal texts. In this way, the experience of thresholds and boundaries and also the liminal transgressions of these boundaries become embedded in writing about the social. Liminal texts as products of liminal actors are thus an expression of the limits of social space. Their product, the liminal texts, are thereby an investigation and consequence of the social world. In this way, they describe the social through their experience of the fragmentation in this social world. As border crossers through the social world, they can report on these liminal experiences in their texts and thereby trigger them as aesthetic practices. Liminal actors use their experiences quite consciously and intentionally to throw themselves into the struggle for the doxa of a field. As explained above, liminal actors experience different kinds of doxa, which means that liminal texts can be understood as an expression of struggles over the logics of fields and their demarcations. These struggles are always concrete and thus bound in time and space in the social realm. Liminal phases are characterized by the struggle for the interpretation of social worlds, such as the struggle for naming what, for example, sociology or literature is and how work and writing may be done in these particular social fields. This is how liminal phases react to the restrictions of fields and fixed definitions of boundaries, undermining them like a mole (Hegel). In these liminal phases, liminal texts work to create new connections and to undermine fixed definitions with indeterminacy. In this way, actors consciously use their liminal texts to reinterpret fixed boundaries of and between fields and to throw themselves into the struggle for these boundaries. In this article, I will interpret three such liminal phases: Deliterarisation (Lepenies) and The Long Turn of the Century (Knaller/Moebius). Finally, I will discuss in more detail the liminal phase triggered by the genre of autosociobiographies, also addressing the literary design of this specific liminal phase. The emergence of the genre of autosociobiographies is understood as a liminal phase, which is interpreted using the example of the text corpus of Annie Ernaux. Ernaux’s texts are considered liminal because they are situated between sociology and literature and report on the liminal experiences that have produced Ernaux’s perspective. A perspective of liminality from the place in between: Insights through writing from the edge.Zentrale These dieses Beitrags ist das Oszillieren bestimmter Texte zwischen den Feldern der Soziologie und der Literatur, ohne dass sie je vollständig einem der beiden Bereiche zugeschlagen werden können. Für diesen Zweck werde ich den Begriff der »Liminalität« von Victor Turner (1969) für eine Deutung von Texten, die zwischen gesellschaftlichen Feldern changieren, nutzen – im Sinn von Susanne Knaller, Stephan Moebius und Martina Scholger (2022). Liminalität bedeutet hierbei ein Existieren zwischen Feldern, zwischen verschiedenen Kulturen und Welten; Liminales befindet sich also im Übergang zwischen Etabliertem. Liminale Texte übernehmen die Funktion einer Brücke zwischen den Grenzen, die beispielsweise die Felder Literatur und Soziologie voneinander trennen. Dabei tragen sie aber ebenso Ereignischarakter und überraschen die Ordnungen der Felder, worauf sich diese an sie anpassen müssen. Die Produktion von liminalen Texten kann in zwei Richtungen verfolgt werden, wie in diesem Artikel vorgeschlagen wird: vertikal und horizontal. Auf der vertikalen Achse lassen sich liminale Akteure beobachten, die als »praktische Analytiker« (Bourdieu 1997, 341) über Grenzen hinweggeschritten sind oder sich an diesen befinden. Sie blicken über die Grenzen und in die Abgründe: »Sie befinden sich an Punkten, an denen die gesellschaftlichen Strukturen ›arbeiten‹, und sind deshalb den Widersprüchen dieser Strukturen ausgesetzt« (ebd.). Auf der horizontalen Achse lassen sich liminale Phasen nachvollziehen, in denen sich soziale Felder vermischen, beispielsweise durch Texte, die zwischen den Grenzen der Felder produziert werden. Als Beispiel solch einer liminalen Phase, in der um die Auslegung der Grenzen und Möglichkeiten der Felder gekämpft wird, wird im letzten Teil des Aufsatzes das Genre der Autosoziobiographien besprochen.Peer Reviewe
Physical embodiment and anthropomorphism of AI tutors and their role in student enjoyment and performance
No full textRising interest in artificial intelligence in education reinforces the demand for evidence-based implementation. This study investigates how tutor agents’ physical embodiment and anthropomorphism (student-reported sociability, animacy, agency, and disturbance) relate to affective (on-task enjoyment) and cognitive (task performance) learning within an intelligent tutoring system (ITS). Data from 56 students ( M = 17.75 years, SD = 2.63 years; 30.4% female), working with an emotionally-adaptive version of the ITS “Betty’s Brain”, were analyzed. The ITS’ agents were either depicted as on-screen robots (condition A) or as both on-screen avatars and physical robots (condition B). Physical presence of the tutor agent was not significantly related to task performance or anthropomorphism, but to higher initial on-task enjoyment. Student-reported disturbance was negatively related to initial on-task enjoyment, and student-reported sociability was negatively related to task performance. While physical robots may increase initial on-task enjoyment, students’ perception of certain characteristics may hinder learning, providing implications for designing social robots for education.Deutsche Forschungsgemeinschaft (German Research Foundation)https://doi.org/10.13039/501100001659Peer Reviewe
Pathways to Inclusion? Labor Market Entry Trajectories of Persons With Disabilities in Europe
No full textAlmost a fifth of the population in OECD countries report having a disability and the proportion of students classified as having special educational needs (SEN) has steadily increased over recent decades. While this group faces marginalization in schooling and employment everywhere, there are profound differences in disability‐based disadvantages across countries. However, comparative research on the labor market opportunities of persons with disabilities (PwDs) remains limited, especially regarding school‐to‐work transitions (STWT) that are crucial for subsequent labor market opportunities. Thus, lacking comparative knowledge on how institutional contexts shape these transitions also limits opportunities for policy learning and improvement of supports provided. This study addresses these gaps by analysing longitudinal data from the European Statistics on Income and Living Conditions (EU‐SILC). First, using sequence and cluster analysis, we classify these trajectories and provide an in‐depth analysis of labor market entry patterns for PwDs compared to those without disabilities across 31 European countries. Second, we explore whether the timing of first employment, instability during the STWT, as well as inclusionary or exclusionary transitions vary between these groups and how the disparities between persons with and without disabilities regarding these indicators are related to institutionalized segregation and support structures. Our findings highlight that PwDs usually do not transition more slowly to (some form of) employment, yet they experience more instability and less inclusion during their STWT. Segregation exacerbates disadvantages, whereas institutional support structures reduce the disadvantages youth with disabilities face when these programs actively facilitate pathways to inclusion
Essays on seed innovations, collective action, entrepreneurship and performance in previously underutilized crops: A case of African Indigenous Vegetables in Kenya
No full textWertschöpfungsketten wie jene für African Indigenous Vegetables (AIV) bieten Potenzial zur Bekämpfung von Ernährungsunsicherheit, Armut und Arbeitslosigkeit, insbesondere in Sub-Sahara Afrika. Trotz ihrer ökonomischen und ernährungsphysiologischen Bedeutung wurden sie bislang wissenschaftlich wenig berücksichtigt. Diese Dissertation leistet einen Beitrag, indem sie drei empirische Studien zu AIV-Produzenten und -Einzelhändlern in Kenia vorstellt. Die erste Studie untersucht den Einfluss verbesserter Saatgutsorten auf die Produktivität mittels Propensity Score Matching und einer selektivitätskorrigierten stochastischen Meta-Frontier-Analyse. Die Ergebnisse zeigen einen positiven Zusammenhang zwischen Saatgutinnovation und Effizienz, wenngleich das Effizienzniveau insgesamt niedrig bleibt. Die zweite Studie analysiert den vermittelnden Effekt unternehmerischer Orientierung (EO) im Zusammenhang zwischen kollektivem Handeln und Performance. Mittels PLS-SEM zeigt sich, dass kollektives Handeln nur indirekt über EO die Performance beeinflusst. Dies unterstreicht die Rolle von Innovationsfähigkeit, Proaktivität und Risikobereitschaft. Die dritte Studie nutzt GSEM, um die Beziehung zwischen EO-Dimensionen und Beschaffungsstrategien von Einzelhändlern zu analysieren. Sie zeigt, dass Faktoren wie Bildung, Marktzugang und Schulungen EO beeinflussen und komplexere Beschaffungsstrategien begünstigen.
Insgesamt wird deutlich, dass Verhaltensfaktoren, EO und institutioneller Zugang zentrale Hebel zur Stärkung der AIV-Wertschöpfungskette sind.Underutilized value chains, such as those of African Indigenous Vegetables (AIV), offer opportunities to address poverty, improve livelihoods, and enhance food and nutrition security. Despite their significance, these value chains remain underexplored. This dissertation fills this gap by analyzing how seed innovations, collective action, and entrepreneurial orientation (EO) relate to performance and procurement strategies in the AIV value chain, using data from 445 producers and 320 retailers in Kenya. The first paper explores how the adoption of improved seed varieties affects productivity, measured through meta-technical (MTE), allocative (MAE), and economic efficiency (MEE). Using propensity score matching and a selectivity-corrected stochastic meta-frontier model, findings show that behavioral beliefs influence adoption decisions. Adopters of improved seeds demonstrate higher technical and allocative efficiency, though MEE remains low across all groups. The second paper examines the role of EO as a mediator between collective action and performance. Using PLS-SEM on data from 445 farmers, the study finds that collective action positively influences EO, and EO mediates its effect on performance emphasizing the roles of innovativeness, risk-taking, and proactiveness in realizing the benefits of farmer cooperation. The third paper uses GSEM to investigate how EO dimensions shape procurement strategies among 320 AIV retailers. Findings indicate that EO traits such as proactiveness and competitiveness reduce reliance on informal contracts. Retailer characteristics like education, market type, and training access significantly influence EO and procurement decisions. The study highlights the importance of enabling access to resources and training to support formal, resilient procurement strategies
Exploring gender dynamics in climate-smart agriculture adoption: a study in semi-arid Dodoma, Tanzania
No full textIntroduction: Climate change threatens agricultural production, particularly in developing countries, where agriculture supports over 2.5 billion people. Women, who comprise 43% of the agricultural labor force, are particularly vulnerable due to gender inequalities, especially in African societies. While Climate-Smart Agriculture (CSA) offers potential benefits to mitigate the adverse effects of climate change, its benefits are not evenly distributed, with a notable gender gap in adoption. Methods: This study investigates how gender dynamics influence CSA adoption patterns in Tanzania’s semi-arid Dodoma regions, using a mixed-methods approach. The study included a survey of 380 households and focus group discussions with 75 participants. Results: The results reveal lower CSA adoption among female-headed households (51% non-adopters) compared to male-headed households (38% non-adopters). Probit and Poisson regression analyses identify several key determinants of adoption and adoption intensity, including marital status, livestock ownership, land access, and the availability of extension services. Female-headed households face unique barriers, such as smaller landholdings, labor constraints, and limited access to credit, training, and group membership. The study also highlights the absence of female extension workers in villages. Discussion: The findings emphasize the need for targeted policy interventions to address these challenges and promote more equitable CSA adoption. These include implementing land reforms to ensure equitable land access for women, designing inclusive training programs that accommodate women’s time constraints, and increasing the representation of female extension workers to enhance CSA knowledge dissemination among female farmers. Additionally, improving access to credit facilities for female farmers, strengthening social networks through farmer groups, and improving transport infrastructure to reduce logistical barriers are crucial to further supporting CSA adoption. These targeted interventions are essential for overcoming gender-specific barriers, ensuring that CSA benefits are more equitably distributed, and ultimately supporting sustainable agricultural development.Peer Reviewe
Drought research priorities, trends, and geographic patterns
No full textDrought research addresses one of the major natural hazards that threatens progress toward the Sustainable Development Goals. This study aims to map the evolution and interdisciplinarity of drought research over time and across regions, offering insights for decision-makers, researchers, and funding agencies. By analysing more than 130 000 peer-reviewed articles indexed in SCOPUS from 1901 to 2022 using latent Dirichlet allocation (LDA) for topic modelling, we identified distinct shifts in research priorities and emerging trends. The results reveal that plant genetic research for drought-tolerant genotypes and advancements in drought forecasting are the most dominant and continuously growing areas of focus. In contrast, the relative importance of topics such as ecology, water resource management, and forest research has decreased. Geospatial patterns highlight a universal focus on forecasting methods, with a strong secondary emphasis on policy and societal issues in Africa and Oceania. Interdisciplinarity in drought research experienced a marked decline until 1983, followed by a steady increase from 2007 onward, suggesting a growing integration of diverse fields. Emerging topics in recent years signal evolving priorities for future research. This analysis provides a comprehensive overview of drought research trends across sectors and regions, offering strategic guidance for aligning research efforts with drought resilience goals. The findings are crucial for research funding agencies and policymakers aiming to prioritize areas with the highest potential to mitigate drought impacts effectively.Peer Reviewe
A small signaling domain controls PPIP5K phosphatase activity in phosphate homeostasis
No full textInositol pyrophosphates (PP-InsPs) are eukaryotic nutrient messengers. The N-terminal kinase domain of diphosphoinositol pentakisphosphate kinase (PPIP5K) generates the messenger 1,5-InsP8, the C-terminal phosphatase domain catalyzes PP-InsP breakdown. The balance between kinase and phosphatase activities regulates 1,5-InsP8 levels. Here, we present crystal structures of the apo and substrate-bound PPIP5K phosphatase domain from S. cerevisiae (ScVip1PD). ScVip1PD is a phytase-like inositol 1-pyrophosphate histidine phosphatase with two conserved catalytic motifs. The enzyme has a strong preference for 1,5-InsP8 and is inhibited by inorganic phosphate. It contains an α-helical insertion domain stabilized by a structural Zn2+ binding site, and a unique GAF domain that channels the substrate to the active site. Mutations that alter the active site, restrict the movement of the GAF domain, or change the substrate channel’s charge inhibit the enzyme activity in vitro, and Arabidopsis VIH2 in planta. Our work reveals the structure, enzymatic mechanism and regulation of eukaryotic PPIP5K phosphatases.Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (Swiss National Science Foundation)https://doi.org/10.13039/501100001711Howard Hughes Medical Institute (HHMI)https://doi.org/10.13039/100000011Peer Reviewe
La locura en la narrativa cervantina
No full textCervantes‘ erzählerische Literatur ist voller Wahnsinniger. Trotz der Unzahl an Dissertationen darüber fällt es auf, dass die Definitionen von Wahnsinn, mit denen Cervantisten oft arbeiten, nicht aus der Literatur stammen. Don Quijote ist aus der Medizin, der Psychologie, der patriotischen Melancholie des spanischen Goldenen Zeitalters… interpretiert worden. Solche Interpretationen sind nur retrospektiv möglich, denn sie basieren auf Gedankensysteme, die nach Veröffentlichung des Quijote entstanden. Diese Arbeit schlägt eine Untersuchung der wichtigsten Cervantinischen Wahnsinnigen mittels ausschließlich literarischer Kriterien vor, ausgehend von der wenig orthodoxen These des fingierten Wahnsinns.
Der Text ist in drei Teile aufgeteilt. Der erste beschäftigt sich mit der Wahrhaftigkeit von Don Quijotes Wahnsinn: startend von der Simulation, Dissimulation und Diskretion (Accetto, Ribadeneyra, Gracián) aus dem spanischen Goldenen Zeitalter, über die ersten Erwähnungen der Vortäuschung (Unamuno), bis zu den ersten expliziten Formulierungen der These des fingierten Wahnsinns (Papini, Torrente Ballester) und den religiösen Folgen des Fingierens (Maestro, Sánchez Berrocal). Der zweite Teil legt einen systematischen Ansatz für die Diagnostik und Klassifizierung der Cervantinischen Wahnsinnigen im Quijote und in den Exemplarischen Novellen dar, unter der Nutzung von Tabellen. Im dritten Teil werden der Lizentiat Vidriera, Cardenio, der alte Carrizales, die Cañizares, der Leutnant Campuzano und Sancho Panza unter dem erwähnten Ansatz analysiert.
Die Arbeit zeigt, wie die These des fingierten Wahnsinns Don Quijotes Status als schlechthin Cervantinischer Wahnsinnige erklärt. Sie verbindet Cervantes‘ Denken mit der spinozistischen Entmythisierung der Religion und suggeriert, dass Cervantes, der schwerlich ein Atheist im modernen Sinne war, vielleicht das Fingieren seiner Figuren zum Dissimulieren seines eigenen Antiklerikalismus benutzt hat und somit der Zensur entkommen ist.Cervantine narrative literature is replete of madmen. Although dissertations on this matter were written in a large extent, it is curious that the definitions of madness with which Cervantes’ investigators often work do not stem from within literature itself. Don Quijote has been interpreted from the viewpoints of medicine, of psychology, of the Spanish Golden Age’s melancholic patriotism… Such readings are only possible in retrospective, since they rely on systems of thought developed after the publication of the Quijote. This essay proposes an examination of the main Cervantine madmen using purely literary criteria, assuming the less orthodox thesis of the probable feigning of madness.
The text is divided in three parts. The first discusses the veracity of Don Quijote’s madness: starting from notions from the Spanish Golden Age such as simulation, dissimulation and discretion (Accetto, Ribadeneyra, Gracián), through the first references to feigning (Unamuno), to the first explicit formulations of the thesis of feigned madness (Papini, Torrente Ballester) and the religious consequences of such feigning (Maestro, Sánchez Berrocal). The second part presents a systematic approach for the diagnosis and classification of the Cervantine madmen in the Quijote and the Exemplary novels, using tables for this purpose. The third part contains the analysis of the graduate Vidriera, Cardenio, the old Carrizales, Cañizares, the lieutenant Campuzano and Sancho Panza by this very approach.
The essay shows how the thesis of feigned madness can explain why Don Quijote is the quintessential Cervantine madman. It connects Cervantes’ thinking with Spinoza’s demystifying of religion and it suggests that the former, while hardly an atheist in the modern sense of the word, maybe used his characters’ feigning as a way of dissimulating his own anticlericalism and so evading censorship
Magnus Brechtken (Hrsg.), Aufarbeitung des Nationalsozialismus. Ein Kompendium. Göttingen, Wallstein 2021
No full textRezensierte Publikation: Magnus Brechtken, Aufarbeitung des Nationalsozialismus. Ein Kompendium. 2021 Wallstein-Verlag GmbH Göttingen, 978-3-8353-5049-6, € 34,–Peer Reviewe