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Schriftspracherwerb im Anfangsunterricht der Grundschule für heterogene Lerngruppen auf Basis einer Differenzierungsmatrix
No full textIn der Arbeit wird aufgezeigt, wie das Zusammenspiel von Fachwissenschaft und Didaktik zu einem gelungenen Schriftspracherwerb im Anfangsunterricht beitragen kann. Heterogänität der Lerngruppe, einschließlich sozioökonomischer Unterschiede, Mehrsprachigkeit und individueller Lernausgangslagen, wird hierbei als Normalfall verstanden und die Bedeutung von Sprachhandlungskompetenz in diesem Zusammenhang hervorgehoben. Der Beitrag bietet eine theoretische und praktische Grundlage, um den eigenen Unterricht zu individualisieren und zu optimieren. Hierzu werden die linguistischen Grundlagen deutscher Orthographie detailliert erläutert sowie ausgewählte Modelle des Schriftspracherwerbs diskutiert. Anstelle von Mono-Prinzip-Modellen, wie sie vorrangig im Deutschunterricht verwendet werden, wird demgegenüber das didaktische Konzept einer Differenzierungsmatrix vorgestellt, das die anwendungsbezogene Komplexität orthographischer Prinzipien besser abbilden kann. Vertikal bietet die Matrix verschiedene Schwierigkeitsgrade, horizontal wird je ein Phänomen pro Prinzip dargestellt. Schüler/-innen haben die Möglichkeit, Aufgaben auf verschiedenen Niveaustufen und mit unterschiedlichen linguistischen Schwerpunkten zu bearbeiten, sodass sie ihren eigenen Lernweg wählen können. Die auf den Schriftspracherwerb ausgelegte Matrix dient den Schüler/-innen so als Stütze im Lernprozess, gleichzeitig gewährt sie einen Überblick über die Komplexität des Themenbereichs. Sie soll dabei helfen, ein metakognitives Verständnis für die Struktur und Funktion von Sprache und Schrift zu entwickeln. Dabei unterstützt die Matrix inklusiven Unterricht, indem sie Lernangebote für alle Schüler/-innen schafft und kooperative Lernformen fördert.The paper shows how the interplay between specialist knowledge and didactics can contribute to successful written language acquisition in early education. Heterogeneity within the learning group, including socio-economic differences, multilingualism and individual learning backgrounds, is understood as the norm, and the importance of language competence in this context is emphasised. The article provides a theoretical and practical basis for individualising and optimising one's own teaching. To this end, the linguistic foundations of German orthography are explained in detail and selected models of written language acquisition are discussed. Instead of mono-principle models, which are primarily used in German lessons, the didactic concept of a differentiation matrix is presented, which can better reflect the application-related complexity of orthographic principles. Vertically, the matrix offers different levels of difficulty, while horizontally, one phenomenon per principle is presented. Students have the opportunity to work on tasks at different levels and with different linguistic focuses, allowing them to choose their own learning path. The matrix, which is designed for written language acquisition, thus serves as a support for students in the learning process, while at the same time providing an overview of the complexity of the subject area. It is intended to help develop a metacognitive understanding of the structure and function of language and writing. In doing so, the matrix supports inclusive teaching by creating learning opportunities for all students and promoting cooperative forms of learning
The Impact of Gas Cluster Ion Beam Sputtering on the Chemical and Electronic Structure of Methyl Ammonium Lead Iodide Thin Films
No full textThe article processing charge was funded by the Open Access Publication Fund of Humboldt-Universität zu Berlin.The stability and performance of metal halide perovskite (MHP) optoelectronic devices are significantly influenced by the chemical and electronic properties of their interfaces, often studied using photoelectron spectroscopy (PES). MHP films, containing organic cations, are susceptible to surface modifications under common experimental conditions, necessitating careful analysis. This study examines the effects of argon gas cluster ion beam (GCIB) sputtering, considered gentler and more suitable for depth‐profiling than standard argon ion sputtering, on methylammonium lead iodide using PES. Long‐term exposure to argon clusters with 3.2 and 1.5 eV per Ar atom causes significant degradation, including cation loss and metallic lead formation. However, short‐term exposure (<60 min) at 1.5 eV per Ar atom effectively reduces surface contamination without noticeable degradation, allowing access to intrinsic electronic properties. This gentle cleaning reveals a 220 meV energy difference between the contaminated surface and the valence band onset of the intrinsic MHP potentially improving energy level alignment with electron transport layers. These results demonstrate that low energy GCIB sputtering can serve as a non‐destructive surface cleaning method, enhancing PES investigations and supporting fundamental device studies of MHPs.Deutsche Forschungsgemeinschaft (DFG, German Research FoundationPeer Reviewe
A partially disordered crystallographic shear block structure as fast-charging negative electrode material for lithium-ion batteries
No full textA well-ordered crystalline structure is crucial in battery electrodes, as the dimensionality and connectivity of the interstitial sites inherently influence Li+ ions diffusion kinetics. Niobium tungsten oxides block structures, composed of ReO3-type blocks of specific sizes with well-defined metal sites, are promising fast-charging negative electrode materials. Structural disorder is generally detrimental to conductivity or ion transport. However, here, we report an anomalous partially disordered Nb12WO33 structure that significantly enhances Li-ion storage performance compared to the known monoclinic Nb12WO33 phase. The partially disordered phase consists of corner-shared NbO6 octahedra blocks of varied sizes, including 5×4, 4×4, and 4×3, with a disordered arrangement of distorted WO4 tetrahedra at the corners of the blocks. This structural arrangement is robust during lithiation/delithiation, exhibiting minor local structure changes during cycling. It enables accelerated Li-ion migration, resulting in promising fast-charging performance, namely, 62.5 % and 44.7 % capacity retention at 20 C and 80 C, respectively. This study highlights the benefits of introducing disorder into niobium tungsten oxide shear structures, through the establishment of clear structure-performance correlations, offering guidelines for designing materials with targeted properties.Peer Reviewe
Molecular mechanisms of cellular memory following a single drug exposure in dopaminergic neurons
No full textDopaminerge Neuronen (DNs) sind in ihrer Physiologie, Verschaltung, Krankheitsanfälligkeit und transkriptomischer Profile stark heterogen. DNs des Ventralen tegmentalen Areals (VTA) im Mittelhirn spielen eine zentrale Rolle bei Suchtprozessen und reagieren als Erstes auf eine einmalige Kokainexposition, die synaptische Umbauprozesse auslöst und zur Langzeitpotenzierung (LTP) führen kann. Während diese Veränderungen rasch auftreten und sich meist innerhalb einer Woche zurückbilden, sind die molekularen Mechanismen einer anhaltende zelluläre Erinnerung an die Erstexposition noch unzureichend verstanden. Zur Untersuchung des Epigenetischen Langzeitgedächtnisses in VTA-DNs führte ich eine single-cell multiome-Analyse (RNA-seq + ATAC-seq) zu mehreren Zeitpunkten nach akuter Kokainexposition bei Nagetieren durch. Neben unmittelbaren Effekten blieben bestimmte Gene auch 14 Tage nach der Kokaingabe differentiell exprimiert, darunter eine Hochregulation von Neuropeptiden, die mit erhöhtem Rückfallrisiko assoziiert sind, wie Cartpt, das zum kokaininduzierten Verhalten nach Abstinenz beiträgt. Auf Chromatinebene zeigte der Transkriptionsfaktor Activator Protein 1 (AP-1) ein biphasisches Muster: Einige Regionen waren transient geöffnet, andere langfristig reprimiert, was auf einen Übergang von Stimulus-getriebener Transkription zu dauerhafter Stilllegung hindeutet. Parallel beobachteten wir einen Verlust der DN-Identität, erkennbar an verringerter Zugänglichkeit DN-spezifischer Foxa1/Foxa2-Bindungsstellen und Herunterregulation von DN-Markergenen. Schließlich wurden Zielgene des Polycomb Repressive Complex 2 (PRC2) transient oder dauerhaft hochreguliert. Diese Befunde deuten darauf hin, dass eine unvollständige Wiederherstellung der PRC2-gesteuerten Repression zentral für die anhaltende zelluläre Antwort sein könnte. Insgesamt zeigt meine Arbeit dynamische Veränderungen in Genexpression und Chromatinregulation, die der verzögerten Erholung nach einer ersten Kokainexposition zugrunde liegen.Dopaminergic neurons (DNs) are highly heterogeneous in their physiology, circuitry, disease susceptibility, and transcriptomic profiles. Among them, DNs in the ventral tegmental area (VTA) of the midbrain play a central role in addiction and are the first to respond to a single cocaine exposure, initiating synaptic remodeling that can lead to long-term potentiation (LTP). While these cocaine-induced synaptic changes are rapidly triggered and usually resolve within a week, the molecular mechanisms encoding a lasting cellular memory of the initial exposure remain poorly understood. To investigate this long-term cellular memory in VTA-DNs, I performed single-cell multiome (paired RNA-seq and ATAC-seq) at several time points after acute cocaine exposure from the rodent VTA, and analyzed the DN population. In addition to the immediate effects, genes remained differentially expressed even 14 days post-administration, including upregulation of neuropeptides linked to relapse vulnerability such as Cartpt, which contributes to cocaine-induced behavior after abstinence. At the chromatin level, a biphasic pattern of Activator Protein 1 (AP-1) binding emerged: some regions were transiently opened, while others AP-1 binding sites became long-term repressed, indicating a shift from stimulus-driven transcription to long-term silencing. In parallel, I observed progressive loss of DN identity, marked by reduced accessibility at Foxa1/Foxa2 sites and downregulation of DN-specific genes. Finally, our data revelaed that a single cocaine exposure triggered upregulation of Polycomb Repressive Complex 2 (PRC2) target genes, with both transient and persistent dynamics. These findings suggest that incomplete restoration of PRC2-mediated repression could be central to the sustained cellular response. Overall, my work reveals dynamic changes in gene expression and chromatin regulation underlying delayed recovery after an initial cocaine exposure
The effect of non-stoichiometry in Sb2Se3 films on their phonon and electronic properties in the infrared range
No full textDue to the noticeable part of Sb2Se3 films in solar cell technology, the deposition of Sb2Se3 films with the desirable content and improved crystalline perfection is of crucial importance. Therefore, extensive experimental and theoretical studies of the electronic and phonon properties of these materials are of interest. In this work, the stoichiometry and morphology of antimony selenide films are correlated to their optical properties in the far-infrared regime and compared to theoretically calculated properties for an ideal crystal. For this study, the reflectance of a series of 1.4–1.7 μm thick SbxSey layers, produced on soda-lime glass substrates by molecular beam chemical deposition, was measured in the spectral range of 25–5000 cm⁻¹ using an FT-IR spectrometer and synchrotron radiation. The near-surface and bulk crystallographic structure and phase composition were previously determined using grazing incidence X-ray diffraction (GIXRD) under varying incident angles. The chemical composition and morphology were investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). It was shown that the spectral positions of numerous maxima of the reflectance of SbxSey layers for various x/y indices in the phonon excitation range of 25–230 cm⁻¹ are consistent with the positions of the maxima of the imaginary part of the dielectric function of Sb2Se3 crystals, calculated within the framework of density functional theory. A significant increase in the reflectance values was observed for SbxSey layers containing the largest relative amount of antimony x/y, which may be due to the increased content of the metallic form of antimony compared to the amount of the pure Sb2Se3 semiconducting phase. A correlation was found between the technological parameters of production (temperature) and the final chemical composition and morphology of the SbxSey layers. To explain the observed relationships, calculations of the cohesive energy of Sb2Se3 and Sb crystals and the binding energy of the residual antimony atom inside and on the surface of the antimony selenide supercell were performed. The main conclusions of the theoretical calculations are consistent with the results of EDX and XRD measurements of the SbxSey layers.Peer Reviewe
Understanding food democracy through practitioner viewpoints: a Q-method study of local US food policy councils
No full textLocal food policy councils (FPCs) have formed as spaces for public participation and collective activism with a potential to democratize food systems, and as such have been explored in research as vehicles to realize normative concepts like food democracy. However, food democracy is a multi-dimensional term that conveys different ideas for policy and practice depending on how the meaning of democracy is understood. By using a Q-methodology approach to identify shared democracy viewpoints of individuals in US-based FPCs, this study addresses the question: which norms and ideas of food democracy resonate with practitioners, and how do these perspectives on the meaning of democracy reflect political and practical realities for FPCs in the US context? Sixteen representatives of FPCs across the country ranked 30 statements related to democracy in food systems in an online Q-study and provided expository exit-survey responses. Through interpretation of results, four democracy viewpoints were identified and elaborated, which were: 1) social justice-oriented, 2) results-oriented, 3) redistribution-oriented, and 4) local value chain-oriented fooddemocracy. These nuanced democracy perspectives contribute to the distinct, situated understandings of food democracy from practitioners’ point of view, but taken together, construct a shared concept of food democracy as working to diffuse either-or thinking in a polarized US food policy context and create an opportunity for more inclusive, equitable food systems despite structural barriers.Open Access funding enabled and organized by Projekt DEAL.Humboldt-Universität zu Berlin (1034)Peer Reviewe
Rethinking knowledge systems for agroforestry: Insights from the mental models of cacao farmers in Colombia
No full textAgroforestry is a sustainable land-use strategy that requires better integration of diverse knowledge systems. This paper examines how formal knowledge systems for cacao agroforestry systems in Colombia are structured, and how farmers understand and manage these systems. We interviewed 42 actors involved in knowledge production and dissemination and worked with 18 farmers to create mental maps of their management practices. Our findings show that formal knowledge systems remain predominantly top-down and scientific-based, despite increasing recognition of local knowledge. Farmers’ mental models reflect this, showing reliance on external advice and simplified cause-and-effect thinking. When theoretically pooling farmers’ perspectives, we observe a more comprehensive understanding of agroforestry, suggesting that social learning can strengthen their independence and adaptive capacity. Moreover, farm management is shaped by context-dependent variables such as climate seasonality and market access, thus highlighting the importance of integrating farmers’ experiential knowledge into agroforestry design and dissemination for more sustainable, context-sensitive decision-making.Open Access funding enabled and organized by Projekt DEAL.International Climate Initiative (IKI)Helmholtz-Zentrum für Umweltforschung GmbH - UFZ (4215)Peer Reviewe
current state and future opportunities
No full textDer steigende Fleischkonsum erhöht den Druck auf Landressourcen und macht die Tierproduktion für etwa 20% der menschengemachten Treibhausgasemissionen verantwortlich. Sie trägt zur Wüstenbildung, Abholzung, Wasserverschmutzung und zum Verlust von Biodiversität und Ökosystemleistungen bei. Die Quantifizierung des ökologischen Fußabdrucks ist schwierig, da Weidetiere mobil sind und Flächen unterschiedlich intensiv nutzen. Diese Dissertation untersucht Kasachstan, ein Land mit großer Weidefläche und wechselvoller Weidegeschichte: vom transhumanten Nomadentum über sowjetische Sesshaftigkeit bis zur teilweisen Rückkehr mobiler Weidewirtschaft. Der Viehbestand erreichte seinen Höhepunkt gegen Ende der Sowjetzeit, fiel in den 1990er Jahren und steigt seither wieder. Überweidung war verbreitet, doch entfernte Weiden blieben ungenutzt. Die Tragfähigkeit der Graslandsysteme ist weitgehend unbekannt. Angesichts der Expansion der Viehwirtschaft, insbesondere im Rindfleischsektor, ist eine nachhaltige (Wieder-)Nutzung entscheidend. Ein räumliches Modell zeigt, dass 2015 etwa die Hälfte der Weideflächen genutzt wurde, meist mit geringer Intensität. Eine 31% Steigerung der Rindfleischproduktion wäre ohne Intensivierung möglich. Die jährliche Weideintensität (2001–2019) korreliert negativ mit der verbrannten Fläche, stärker als klimatische Variablen. Pferdefleisch bietet eine nachhaltige Alternative: Es ist ernährungsphysiologisch hochwertig, verursacht weniger Methan, erfordert aber mehr Fläche. Eine Umstellung würde den Fleischkonsum senken. Pferde sind aufgrund ihrer Mobilität, Robustheit und Fleischqualität besonders geeignet, sowohl zur Fleischproduktion als auch zur Brandminderung beizutragen. Eine koordinierte Ausweitung der Weidewirtschaft mit Fokus auf Pferdehaltung könnte ökologische Funktionen sichern und Risiken reduzieren.The rising demand for meat and animal products has strained land resources and created a livestock sector responsible for 20% of anthropogenic greenhouse gas emissions, linked to desertification, deforestation, water contamination, and biodiversity loss. Quantifying this strain remains difficult due to livestock mobility and variable grazing intensity. This dissertation focuses on Kazakhstan, a country with vast grasslands and a long pastoralist history, which shifted from transhumant nomadism to Soviet-era sedentary grazing and partially back to mobile systems post-Soviet. Livestock numbers peaked near the end of the Soviet period, declined in the 1990s, and have since rebounded. Overgrazing was common, but restricted movement left distant pastures unused, and the true carrying capacity of Kazakh grasslands remains unclear. With current livestock expansion—especially beef—sustainable (re)use of grasslands is critical. Recurrent fires are key to maintaining biodiversity and ecological function, and grazing influences fire regimes more than climate factors, though this relationship is poorly understood. Kazakhstan’s history offers a unique context to study grazing’s impact on fire occurrence. Part one presents a spatial model assessing grazing demand; in 2015, about half of pastureland was used, mostly at low intensity. A 31% increase in beef production could occur without intensification. Part two correlates grazing intensity (2001–2019) with burned area, controlling for climate variables. Grazing demand showed a strong negative relationship with burned area and explained more variation than climate factors. Part three explores horsemeat as a beef alternative: nutritionally superior, similar in taste, and lower in methane emissions. However, horses require more land, and full conversion would likely reduce overall meat consumption. Horses are well suited to support both meat production and fire mitigation
Interrogating the Role of the Tuberculous Granuloma in Host Response and Treatment
No full textTuberkulose, verursacht durch Mycobacterium tuberculosis, ist eine der weltweit häufigsten Todesursachen. Eine große Einschränkung bei der Behandlung ist das Granulom, eine organisierte Ansammlung von Immunzellen um die Bakterien. Die komplexe zelluläre Architektur des Granuloms kann die Diffusion von Medikamenten behindern und so zu Therapieversagen führen. Kürzlich wurde gezeigt, dass die Organisation des Granuloms auf einer Makrophagen-zu-Epithel-Transformierung basiert, die durch den Typ 2-Immunregulator stat6 gesteuert wird. In dieser Arbeit habe ich untersucht, ob stat6 gezielt beeinflusst werden kann, um die Wirksamkeit von Antibiotika zu erhöhen. Zunächst habe ich gezeigt, dass das vollständige Fehlen von Granulomen in stat6-defizienten Tieren die Aktivität von zwei in der Therapie häufig eingesetzten Medikamenten erhöhte. Anschließende Tests haben ergeben, dass Bakterien außerhalb von Granulomen eine höhere Stressreaktion auf die Behandlung aufwiesen als Bakterien innerhalb von Läsionen. Zusammen deuten diese Ergebnisse darauf hin, dass die Destabilisierung des Granuloms die Therapie fördern könnte. Längerfristige Experimente haben überraschenderweise gezeigt, dass stat6-defiziente Zebrafische zunächst keine organisierten Granulome bilden konnten, aber im späteren Verlauf der Infektion organisierte Granulome entwickelt haben. Dies deutet auf Mechanismen hin, die die Granulombildung unabhängig von stat6 vorantreiben und weitere Ansatzpunkte für die therapeutische Modulation der Granulomstruktur darstellen könnten. Zusätzlich habe ich neuartige Werkzeuge zur Generierung von Zebrafisch-Transgenen entwickelt und diese in ein umfassendes Toolkit für die Zebrafisch-Immunologie integriert, das ich ImPaqT genannt habe. ImPaqT ermöglicht eine flexible Transgen-Gestaltung, die kombinatorische Verwendung von DNA-Konstrukten und die einfache Einbindung von zusätzlichen Elementen und kann so die Erzeugung von transgenen Zebrafischen erleichtern.Tuberculosis, caused by Mycobacterium tuberculosis, remains a major cause of mortality worldwide. One of the major limitations in therapy is the granuloma, an organized aggregate of host immune cells encapsulating the bacteria. Its complex cellular architecture limits the diffusion of antibiotics, leading to therapy failure. Recently, it has been found that granuloma organization is based on a macrophage-to-epithelial transformation that is driven by the type 2 immune regulator stat6. In this research project, I investigated whether stat6 can be targeted to increase antibiotic efficacy. First, I have demonstrated that the complete absence of granulomas in stat6-deficient animals increased the activity of two drugs commonly used for therapy. Subsequent testing of bacteria found that bacteria outside of granulomas have increased stress responses to therapy compared to bacteria inside lesions. Together, these findings indicate that the disorganization of the granuloma could improve antibiotic therapy. Long-term experiments surprisingly showed that stat6-deficient animals were initially unable to form organized granulomas but developed organized granulomas later in the course of infection. This demonstrates that there are mechanisms that can drive granuloma formation independently of stat6 and could represent further targets for the therapeutic modulation of granuloma structure. Additionally, I have developed novel tools for the generation of zebrafish transgenes, which I incorporated into a larger toolkit for zebrafish immunology, termed ImPaqT. ImPaqT allows for a flexible transgene design, combinatorial use of DNA constructs and easy incorporation of additional elements, and ultimately, facilitates the generation of transgenic zebrafish
Co-designing policy mixes to overcome lock-ins towards sustainable agri-food systems: the case of the pig sector transformation in Brandenburg, Germany
No full textMaking agri-food systems in Europe more sustainable often requires systemic change. Transformative rather than incremental change is difficult if agri-food systems are locked into unsustainable practices by a range of institutional, cultural, social and financial factors that create mutually reinforcing barriers to change. Institutionalised public policies tend to further stabilise the established system through multiple feedback effects, bolstering unsustainable path dependencies. Co-design has been discussed as an innovative approach to developing operational options in agri-food systems. However, co-design methods have rarely been applied to develop policy options. This paper presents the experiences with a policy co-design process for the envisioned sustainability transformation of conventional pork production in Brandenburg, Germany. Combining an agri-food system perspective with the policy co-design literature, we developed (1) a process template for a participatory policy co-design process to overcome barriers and lock-ins along the three levels of policy mixes: objectives, instruments and calibration; and (2) a conceptual framework for the systematic analysis of this process and its output. The successful implementation of the policy co-creation process in the case study constitutes a proof of concept. An unexpected limitation was that full specification of instrument calibrations was not realistic. In policy processes, this is typically part of hard negotiation processes. The systematic analysis of the participatory development of policy options along the three levels of policy mixes confirms and refines the possible role of co-design approaches for public policies in the transformation of agri-food systems.Open Access funding enabled and organized by Projekt DEAL.Humboldt-Universität zu Berlin (1034)Peer Reviewe