Ludwig-Maximilians-Universität München
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Adolescents’ Norms of Self-Presentation on Snapchat: Bitmojis as an Expression of Identity Development
Get PDFAdolescents’ self-presentation on social media as an expression of identity development is influenced by personal norms and perceived social norms of relevant others. Snapchat is popular and widely used by adolescents to express themselves. A Bitmoji, as an alternative to a traditional profile picture, offers a wide range of self-presentation options through an avatar editor, including body stature and pose, individual facial features, and (branded) clothing. Based on 53 in-depth interviews with adolescents between the ages of 11 and 16, we investigated how Bitmojis are used for self-presentation and where the underlying action-guiding norms come from. Our study revealed the high perceived relevance of Bitmojis among adolescents who consciously use their Snapchat avatar to express themselves. True self-behavior is essential for some adolescents, evidenced by single, regular, or daily changes to Bitmojis’ hairstyles and clothing. Others engage in false self-behavior, displaying an ideal self to hide disliked body features or showing a false self to experiment with their digital identity. The perceived social norms of the peer group play an important role for adolescents as their personal norms
Animal Husbandry, Cultural Change, and Economic Networks: An Archaeozoological Perspective on the Transformation of Iron Age Oppida Societies
Get PDFIn the 2nd century bce, with the Iron Age Oppida Civilisation, Central Europe experienced an unprecedented degree of urbanization, economic centralization, and supra-regional exchange. However, from 80 bce onwards, in the Northern Alpine Foreland (present-day southern Germany), these structures declined, leading to the abandonment of both urban and rural settlements. Various factors, such as landscape overexploitation and military conflicts, have been proposed to explain this decline. Concurrently, cultural transfer and possible migration movements from the Central German Upland Zone gave rise to the Southeast Bavarian Group (SEBG), an Iron Age community that emerged north of the Alps, differing from Oppida societies in terms of material culture and settlement structure. This paper aims to explore the effects of these socio-economic upheavals on livestock farming by comparing faunal assemblages from the Oppida Civilisation and the SEBG, focusing on two categories of archaeozoological data: species distribution and body size development in cattle. Generally, species distribution patterns in SEBG farmsteads show continuity with the preceding Oppida Civilisation, with the exception of the Langenpreising site near Munich, where a high proportion of sheep could suggests economic influences from the Central German Upland Zone. Osteometric results on cattle breeding prompt the hypothesis that a large-sized cattle type of non-local origin appeared in SEBG contexts. We discuss several potential regions as the origin of this allochthonous phenotype, with the most plausible explanation being that these cattle were possibly transferred from Roman Upper Italy through Eastern Alpine Iron Age communities to the SEBG. However, because of the limited osteometric data set, this is to be seen as a working hypothesis that requires further testing. From an archaeozoological perspective, the end of the Iron Age was characterized by the decline of proto-urban structures on the one hand and the emergence of new economic networks on the other
Policy Changes Post-Brexit: Evidence of Alignment and Divergence in the Field of Environmental Policy
Get PDFForest variables from LiDAR: Drone flight parameters impact the detection of tree stems and diameter estimates
Get PDFEcosystem services provided by central European forests, often dominated by Norway spruce or Scots pine, are increasingly threatened by climate change. Monitoring, while labour intensive, is key to ensure continuing forest health. Consequently, UAV-based LiDAR remote sensing has become a valuable tool. However, the impact of drone flight parameters on LiDAR data quality has not yet been extensively studied. To address this, we first present a methodology for delineating tree stems, estimating their diameter at breast height (DBH), and separating understory vegetation from stems and old-grown trees to subsequently compare the approach to other existing methods. Second, we analyse how drone flight parameters influence the accuracy of forest parameter detection. Our methodology outperformed existing approaches in stem detection and DBH estimation. Understory detection enabled the identification of forest paths, roads, and areas without understory vegetation. Differences in flight parameters had a large effect on the accuracy of the approach. Optimal data usability was achieved by flying the drone at low flight height above the trees, at relatively high speeds, and with high LiDAR stripe overlap, balancing detailed data collection with efficient area coverage. We conclude that the new approach can provide foresters with detailed insights into forest structure and dynamics, reducing the need for extensive fieldwork
TRPV2 channels facilitate pulmonary endothelial barrier recovery after ROS-induced permeability
Get PDFReactive oxygen species (ROS), such as hydrogen peroxide (H2O2), are known signaling molecules that increase endothelial barrier permeability. In this study, we investigated the roles of redox-sensitive transient receptor potential (TRP) ion channels, TRPM2, TRPV2 and TRPV4, in H2O2-induced endothelial barrier dysfunction. Using primary human pulmonary microvascular endothelial cells (HPMEC), we employed impedance-based resistance measurements, Western blot, and immunofluorescence staining to assess the effects of H2O2 on the endothelial barrier. Exposure to sublytic concentrations of H2O2 caused an acute loss of endothelial barrier integrity, accompanied by the cleavage of vascular endothelial cadherin (VE-cadherin), which was also apparent after application of the TRPV2 activator cannabidiol. The inhibition of either TRPV2 with tranilast or a disintegrin and metalloprotease domain-containing protein 10 (ADAM10) with GI254023X significantly reduced H2O2-induced VE-cadherin cleavage, while TRPM2 inhibition by econazole significantly increased H2O2-driven VE-cadherin cleavage and blockage of TRPV4 showed no effect. Although inhibition of either TRPV2 or ADAM10 did not prevent the initial loss of barrier resistance upon H2O2 exposure, both were essential for the subsequent recovery of barrier integrity. Time-course immunofluorescence stainings revealed that HPMEC barrier recovery involved a transient localization of N-cadherin proteins at adherens junctions. This process of cadherin-switching did not occur upon inhibition of TRPV2 or ADAM10. Our results highlight a novel role for TRPV2 as a redox sensitive ion channels in the microvascular endothelium and provide insight into the mechanisms underlying pulmonary microvascular endothelial barrier recovery
Unifying Feature-Based Explanations with Functional ANOVA and Cooperative Game Theory
Get PDFFeature-based explanations, using perturbations or gradients, are a prevalent tool to understand decisions of black box machine learning models. Yet, differences between these methods still remain mostly unknown, which limits their applicability for practitioners. In this work, we introduce a unified framework for local and global feature-based explanations using two well-established concepts: functional ANOVA (fANOVA) from statistics, and the notion of value and interaction from cooperative game theory. We introduce three fANOVA decompositions that determine the influence of feature distributions, and use game-theoretic measures, such as the Shapley value and interactions, to specify the influence of higher-order interactions. Our framework combines these two dimensions to uncover similarities and differences between a wide range of explanation techniques for features and groups of features. We then empirically showcase the usefulness of our framework on synthetic and real-world datasets
[Rezension von] Kramer, Christian (2024): Kollaborative Mehrsprachigkeit in Lehr-/Lernkontexten. Empirische Zugänge an der Schnittstelle von englischer Fremdsprachendidaktik und Mehrsprachigkeitsdidaktik. Berlin: Peter Lang
Get PDFFrom Gulag to Fairy Tales: Boris Sveshnikov as a Soviet Book Designer Between Nonconformist Art and Children’s Literature
Get PDFIn the 1950s–1980s, working as children’s book designers enabled many Soviet nonconformist artists to have a recognized role within the system. This article introduces an interdisciplinary and intermedial perspective on Soviet children’s book illustration by focusing on the work of Boris Sveshnikov (1927–1998). The artist established his visual style while imprisoned in the Gulag. After his release and exoneration, he transferred this graphic aesthetics to the design of various volumes of fairy tales, both folk and literary ones, within the Soviet project of “world literature” for adults and children. The analysis traces Sveshnikov’s engagement with fairytale worlds in image and text as a response to Gulag-wrought trauma and as an aesthetic counterpart to the loosening of socialist realism under conditions of political liberalization.Nas décadas de 1950 a 1980, o trabalho como designers de livros infantis permitiu que muitos artistas soviéticos inconformistas tivessem um papel reconhecido dentro do sistema. Este artigo apresenta uma perspectiva interdisciplinar e intermidiática sobre a ilustração de livros infantis soviéticos, concentrando-se no trabalho de Boris Svechnikov (1927–1998). O artista estabeleceu seu estilo visual em seu período de cárcere no Gulag. Após sua libertação e exoneração, ele transferiu essa estética gráfica para o design de vários volumes de contos de fadas, tanto folclóricos quanto literários, dentro do projeto soviético de “literatura mundial” para adultos e crianças. As ilustrações de Svechnikov estavam enraizadas em três contextos interligados: 1) sua arte inconformista (desenhos de acampamento e, mais tarde, pontilhismo); 2) seu profundo interesse pela literatura romântica e simbolista; e 3) o design de livros da era do Degelo, que colocava em primeiro plano a visualização de textos literários por meio de ilustrações gráficas e letras cursivas. A análise traça o envolvimento de Svechnikov com o universo dos contos de fadas em imagem e texto como uma resposta ao trauma causado pelo Gulag e como uma contrapartida estética ao enfraquecimento do Realismo Socialista sob condições de liberalização política
CO2 flushing and redox as drivers of pre-eruptive amphibole breakdown
Get PDFAmphibole reaction rims record critical pre-eruptive magmatic processes, including storage and ascent dynamics. Although decompression and heating are traditionally viewed as key triggers for amphibole breakdown, variations in rim textures and mineralogy indicate that multiple or fluctuating processes often operate simultaneously. This study presents experimental results demonstrating significant impacts of CO2 flushing and redox (fO2) conditions (versus heating and decompression) on amphibole reaction rim formation in rhyolitic and rhyodacitic melts at shallow crustal conditions. In experiments at 830 °C and 120 MPa, the presence of a mixed XH2O:XCO2 fluid (XCO2 = 0.3–0.7) rapidly induced a reaction, with rim thickness, grain size, aspect ratio, nucleation rate and crystal number density all increasing with CO2 concentration. In contrast, rims produced by heating (880 °C for up to 48 h) had distinct characteristics, while decompression (120 MPa to 65 MPa over 120 h) from the same starting conditions did not produce reaction rims. Increasing oxygen fugacity (fO2 from NNO+1 to RRO [NNO+2]) led to rapid rim formation within 24 h, accompanied by distinct mineralogical changes that favoured the stability of Fe3+ phases. These findings demonstrate that CO2, fO2, heating and decompression each exert unique influences on amphibole breakdown; thus, quantitative textural analysis of amphibole rims can help differentiate the driving mechanisms. Recognising the full range of factors affecting amphibole stability and an understanding of the multi-parametric controls is essential for accurately interpreting pre-eruptive conditions, enhancing our ability to reconstruct magmatic histories, and for assessing volcanic hazards