2,156 research outputs found
Three in one-multiple faunal elements within an endangered european butterfly species
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
We combine low energy muon spin rotation (LE-SR) and soft-X-ray
angle-resolved photoemission spectroscopy (SX-ARPES) to study the magnetic and
electronic properties of magnetically doped topological insulators,
(Bi,Sb)Te. We find that one achieves a full magnetic volume fraction in
samples of (V/Cr)(Bi,Sb)Te at doping levels x 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 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
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 -
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
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
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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