2,156 research outputs found

    Three in one-multiple faunal elements within an endangered european butterfly species

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    Ice ages within Europe forced many species to retreat to refugia, of which three major biogeographic basic types can be distinguished: "Mediterranean", "Continental" and "Alpine / Arctic" species. However, this classification often fails to explain the complex phylogeography of European species with a wide range of latitudinal and altitudinal distribution. Hence, we tested for the possibility that all three mentioned faunal elements are represented within one species. Our data was obtained by scoring 1,307 Euphydryas aurinia individuals (46 European locations) for 17 allozyme loci, and sequencing a subset of 492 individuals (21 sites) for a 626 base pairs COI fragment. Genetic diversity indices, F statistics, hierarchical analyses of molecular variance, individual-based clustering, and networks were used to explore the phylogeographic patterns. The COI fragment represented 18 haplotypes showing a strong geographic structure. All but one allozyme loci analysed were polymorphic with a mean F-ST of 0.20, supporting a pronounced among population structure. Interpretation of both genetic marker systems, using several analytical tools, calls for the recognition of twelve genetic groups. These analyses consistently distinguished different groups in Iberia (2), Italy, Provence, Alps (3), Slovenia, Carpathian Basin, the lowlands of West and Central Europe as well as Estonia, often with considerable additional substructures. The genetic data strongly support the hypothesis that E. aurinia survived the last glaciation in Mediterranean, extra-Mediterranean and perialpine refugia. It is thus a rare example of a model organism that combines attributes of faunal elements from all three of these sources. The observed differences between allozymes and mtDNA most likely result from recent introgression of mtDNA into nuclear allozyme groups. Our results indicate discrepancies with the morphologically-based subspecies models, underlining the need to revise the current taxonomy.Estonian targeted financing project [Sf0180122s08]; DFG graduate school [1319]; [Pest-C/MAR/LA0015/2011]info:eu-repo/semantics/publishedVersio

    Spectroscopic perspective on the interplay between electronic and magnetic properties of magnetically doped topological insulators

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    We combine low energy muon spin rotation (LE-μ\muSR) and soft-X-ray angle-resolved photoemission spectroscopy (SX-ARPES) to study the magnetic and electronic properties of magnetically doped topological insulators, (Bi,Sb)2_2Te3_3. We find that one achieves a full magnetic volume fraction in samples of (V/Cr)x_x(Bi,Sb)2−x_{2-x}Te3_3 at doping levels x ≳\gtrsim 0.16. The observed magnetic transition is not sharp in temperature indicating a gradual magnetic ordering. We find that the evolution of magnetic ordering is consistent with formation of ferromagnetic islands which increase in number and/or volume with decreasing temperature. Resonant ARPES at the V L3L_3 edge reveals a nondispersing impurity band close to the Fermi level as well as V weight integrated into the host band structure. Calculations within the coherent potential approximation of the V contribution to the spectral function confirm that this impurity band is caused by V in substitutional sites. The implications of our results on the observation of the quantum anomalous Hall effect at mK temperatures are discussed

    Spironolactone alleviates schizophrenia-related reversal learning in Tcf4 transgenic mice subjected to social defeat

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    Cognitive deficits are a hallmark of schizophrenia, for which no convincing pharmacological treatment option is currently available. Here, we tested spironolactone as a repurposed compound in Tcf4 transgenic mice subjected to psychosocial stress. In this ‘2-hit’ gene by environment mouse (GxE) model, the animals showed schizophrenia-related cognitive deficits. We had previously shown that spironolactone ameliorates working memory deficits and hyperactivity in a mouse model of cortical excitatory/inhibitory (E/I) dysbalance caused by an overactive NRG1-ERBB4 signaling pathway. In an add-on clinical study design, we used spironolactone as adjuvant medication to the standard antipsychotic drug aripiprazole. We characterized the compound effects using our previously established Platform for Systematic Semi-Automated Behavioral and Cognitive Profiling (PsyCoP). PsyCoP is a widely applicable analysis pipeline based on the Research Domain Criteria (RDoC) framework aiming at facilitating translation into the clinic. In addition, we use dimensional reduction to analyze and visualize overall treatment effect profiles. We found that spironolactone and aripiprazole improve deficits of several cognitive domains in Tcf4tg x SD mice but partially interfere with each other’s effect in the combination therapy. A similar interaction was detected for the modulation of novelty-induced activity. In addition to its strong activity-dampening effects, we found an increase in negative valence measures as a side effect of aripiprazole treatment in mice. We suggest that repurposed drug candidates should first be tested in an adequate preclinical setting before initiating clinical trials. In addition, a more specific and effective NRG1-ERBB4 pathway inhibitor or more potent E/I balancing drug might enhance the ameliorating effect on cognition even further

    Shaping the scientific future of environmental sciences in times of multiple crises: a summary of the 12th SETAC Young Environmental Scientists Meeting in Landau in der Pfalz 2023 -

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    SETAC has a long‑standing history of supporting students and early career scientists in the fields of ecotoxicol‑ ogy and environmental chemistry. The Student Advisory Council (SAC) advocates for the diverse interests of young SETAC members offering guidance to peers and serving as a resounding voice for aspiring scientists in dialogues with the SETAC Europe Council. Founded and shaped by a rewarding liaison between SETAC Europe and its German Language Branch, the SAC now has a strong international representation, with its members being distributed all over Europe. With this publication, we want to build upon the relationship between the SETAC Europe students and the SETAC German Language Branch. The Young Environmental Scientists (YES) Meeting, which was first held as a regular conference 14 years ago, is a key‑ stone event organized by the students of SETAC and the SAC. This year, in 2023, the 12th YES meeting took place in Landau in der Pfalz, Germany. Not only has it been the first European in-person YES Meeting since the COVID‑19 pandemic, but with this year’s iteration, the YES meeting returned to its roots in Landau, where 2009 the very first YES meeting was hosted. From August 28th to September 1st, 107 participants from 37 countries and five continents had the opportunity to show‑ case their research in seven thematic sessions, engage in four workshops, listen to six expert/career talks, and two keynotes from established scientists. In reference to the meeting‑motto science through crises, this comment pays special emphasis on topical program points in touching the ongoing multiple crises. We are convinced that sharing our experience from hosting this conference will underline the importance of continuing this unique meeting format and hopefully inspire future scientific events organized by students for students

    Flame/flow dynamics at the piston surface of an IC engine measured by high-speed PLIF and PTV

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    Resolving fluid transport at engine surfaces is required to predict transient heat loss, which is becoming increasingly important for the development of high-efficiency internal combustion engines (ICE). The limited number of available investigations have focused on non-reacting flows near engine surfaces, while this work focuses on the near-wall flow field dynamics in response to a propagating flame front. Flow-field and flame distributions were measured simultaneously at kHz repetition rates using particle tracking velocimetry (PTV) and planar laser induced fluorescence (PLIF) of sulfur dioxide (SO2). Measurements were performed near the piston surface of an optically accessible engine operating at 800 rpm with homogeneous, stoichiometric isooctane-air mixtures. High-speed measurements reveal a strong interdependency between near-wall flow and flame development which also influences subsequent combustion. A conditional analysis is performed to analyze flame/flow dynamics at the piston surface for cycles with weak and strong flow velocities parallel to the surface. Faster flame propagation associated with higher velocities before ignition demonstrates a stronger flow acceleration ahead of the flame. Flow acceleration associated with an advancing flame front is a transient feature that strongly influences boundary layer development. The distance from the wall to 75% maximum velocity ({\delta}75) is analyzed to compare boundary layer development between fired and motored datasets. Decreases in {\delta}75 are strongly related to flow acceleration produced by an approaching flame front. Measurements reveal strong deviations of the boundary layer flow between fired and motored datasets, emphasizing the need to consider transient flow behavior when modelling boundary layer physics for reacting flows

    A Mixed-Method Approach to Investigating Difficulty in Data Science Education

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    The purpose of this study was to define a methodology to identify any disconnect between students and instructors in data science classrooms through analyzing qualitative data. A combined qualitative and quantitative approach was used for analysis of survey data from students, faculty/instructors, and teaching assistants across three institutions. Using a manual content analysis paired with a TF-IDF analysis, researchers were able to pull out frequently used terms within responses and encode them into categories and subcategories. Trends were identified from these categories and subcategories to examine general areas of disconnect within the data science classroom. Additionally, a quality analysis was run to determine the effectiveness of the phrasing of the questions posed during the survey. As a whole, the methods used throughout this research process provide direction for researchers in interpretation and analysis of the survey data in an efficient and time-sensitive manner. Furthermore, it allows researchers to analyze the quality of responses to give insight towards rephrasing of survey questions in future analyses. Although the research was applied to data science classrooms, this method has the potential to be applied into other fields and areas of study when performed with coordination between a field expert and a data scientist
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