818 research outputs found
Evaluating the Performance of UK Research in Economics:Report commissioned by the Royal Economic Society
Warum kontrolliert die Polizei (nicht)? Unterschiede im Handlungsrepertoire deutscher und französischer Polizisten
"Vor dem Hintergrund der wiederkehrenden Unruhen in den französischen Vorstädten und deren Ausbleiben in Deutschland, wird in vorliegendem Artikel der Frage nachgegangen, inwieweit sich das kollektive Handlungsrepertoire deutscher und französischer Polizisten voneinander unterscheidet. Am Beispiel der Personenkontrolle zeigt sich die Relevanz des beruflichen Normensystems, das kontextabhängig in verschiedene Richtungen weisen kann. In der untersuchten deutschen Großstadt werden Kontrollen besonders in den anerkannt überlasteten Schwerpunkt-Revieren als eine zusätzliche Arbeitsbelastung wahrgenommen und deshalb insgesamt äußerst selten angewendet. In der französischen Stadt dagegen gehören Personenkontrollen zur beruflichen Identität von Polizisten." (Autorenreferat)"Given the recurring unrest in French suburbs and their absence in Germany, this paper examines the question of to what extent the collective action repertoire differs between German and French Police forces. Police powers of stop and search demonstrate the relevance of occupational norms and values, which point in different directions depending on the context. In the studied German City, particularly in the most deprived areas identity checks are recognized as an additional workload by the police, and therefore used less often. In contrast, French police officers perceive identity checks as belonging to their professional identity." (author's abstract
MRI Analysis of White Matter Myelin Water Content in Multiple Sclerosis: A Novel Approach Applied to Finding Correlates of Cortical Thinning
A novel lesion-mask free method based on a gamma mixture model was applied to myelin water fraction (MWF) maps to estimate the association between cortical thickness and myelin content, and how it differs between relapsing-remitting (RRMS) and secondary-progressive multiple sclerosis (SPMS) groups (135 and 23 patients, respectively). It was compared to an approach based on lesion masks. The gamma mixture distribution of whole brain, white matter (WM) MWF was characterized with three variables: the mode (most frequent value) m1 of the gamma component shown to relate to lesion, the mode m2 of the component shown to be associated with normal appearing (NA) WM, and the mixing ratio (λ) between the two distributions. The lesion-mask approach relied on the mean MWF within lesion and within NAWM. A multivariate regression analysis was carried out to find the best predictors of cortical thickness for each group and for each approach. The gamma-mixture method was shown to outperform the lesion-mask approach in terms of adjusted R2, both for the RRMS and SPMS groups. The predictors of the final gamma-mixture models were found to be m1 (β = 1.56, p \u3c 0.005), λ (β = −0.30, p \u3c 0.0005) and age (β = −0.0031, p \u3c 0.005) for the RRMS group (adjusted R2 = 0.16), and m2 (β = 4.72, p \u3c 0.0005) for the SPMS group (adjusted R2 = 0.45). Further, a DICE coefficient analysis demonstrated that the lesion mask had more overlap to an ROI associated with m1, than to an ROI associated with m2 (p \u3c 0.00001), and vice versa for the NAWM mask (p \u3c 0.00001). These results suggest that during the relapsing phase, focal WM damage is associated with cortical thinning, yet in SPMS patients, global WM deterioration has a much stronger influence on secondary degeneration. Through these findings, we demonstrate the potential contribution of myelin loss on neuronal degeneration at different disease stages and the usefulness of our statistical reduction technique which is not affected by the typical bias associated with approaches based on lesion masks
Sources and sinks of methane in sea ice: Insights from stable isotopes
We report on methane (CH4) stable isotope (d13C and d2
H) measurements from landfast sea ice collected near
Barrow (Utqiagvik, Alaska) and Cape Evans (Antarctica) over the winter-to-spring transition. These
measurements provide novel insights into pathways of CH4 production and consumption in sea ice. We
found substantial differences between the two sites. Sea ice overlying the shallow shelf of Barrow was
supersaturated in CH4 with a clear microbial origin, most likely from methanogenesis in the sediments. We
estimated that in situ CH4 oxidation consumed a substantial fraction of the CH4 being supplied to the sea ice,
partly explaining the large range of isotopic values observed (d13C between –68.5 and –48.5 ‰ and d2
H
between –246 and –104 ‰). Sea ice at Cape Evans was also supersaturated in CH4 but with surprisingly
high d13C values (between –46.9 and –13.0 ‰), whereas d2
H values (between –313 and –113 ‰) were in the
range of those observed at Barrow.These are the first measurements of CH4 isotopic composition in Antarctic
sea ice. Our data set suggests a potential combination of a hydrothermal source, in the vicinity of the Mount
Erebus, with aerobic CH4 formation in sea ice, although the metabolic pathway for the latter still needs to be
elucidated. Our observations show that sea ice needs to be considered as an active biogeochemical interface,
contributing to CH4 production and consumption, which disputes the standing paradigm that sea ice is an
inert barrier passively accumulating CH4 at the ocean-atmosphere boundary
Efficient laser-driven proton acceleration from cylindrical and planar cryogenic hydrogen jets.
We report on recent experimental results deploying a continuous cryogenic hydrogen jet as a debris-free, renewable laser-driven source of pure proton beams generated at the 150 TW ultrashort pulse laser Draco. Efficient proton acceleration reaching cut-off energies of up to 20 MeV with particle numbers exceeding 109 particles per MeV per steradian is demonstrated, showing for the first time that the acceleration performance is comparable to solid foil targets with thicknesses in the micrometer range. Two different target geometries are presented and their proton beam deliverance characterized: cylindrical (∅ 5 μm) and planar (20 μm × 2 μm). In both cases typical Target Normal Sheath Acceleration emission patterns with exponential proton energy spectra are detected. Significantly higher proton numbers in laser-forward direction are observed when deploying the planar jet as compared to the cylindrical jet case. This is confirmed by two-dimensional Particle-in-Cell (2D3V PIC) simulations, which demonstrate that the planar jet proves favorable as its geometry leads to more optimized acceleration conditions
Reference genome of Lumpfish Cyclopterus lumpus Linnaeus provides evidence of male heterogametic sex determination through the AMH pathway
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Efficient laser-driven proton acceleration from cylindrical and planar cryogenic hydrogen jets
We report on recent experimental results deploying a continuous cryogenic hydrogen jet as a debris-free, renewable laser-driven source of pure proton beams generated at the 150 TW ultrashort pulse laser Draco. Efficient proton acceleration reaching cut-off energies of up to 20 MeV with particle numbers exceeding 109 particles per MeV per steradian is demonstrated, showing for the first time that the acceleration performance is comparable to solid foil targets with thicknesses in the micrometer range. Two different target geometries are presented and their proton beam deliverance characterized: cylindrical (∅ 5 μm) and planar (20 μm × 2 μm). In both cases typical Target Normal Sheath Acceleration emission patterns with exponential proton energy spectra are detected. Significantly higher proton numbers in laser-forward direction are observed when deploying the planar jet as compared to the cylindrical jet case. This is confirmed by two-dimensional Particle-in-Cell (2D3V PIC) simulations, which demonstrate that the planar jet proves favorable as its geometry leads to more optimized acceleration conditions
Molecular genetic mechanisms of allelic specific regulation of murine Comt expression
A functional allele of the mouse catechol-O-methyltransferase (Comt) gene is defined by the insertion of a B2 short interspersed repeat element in its 3′-untranslated region (UTR). This allele has been associated with a number of phenotypes, such as pain and anxiety. In comparison with mice carrying the ancestral allele (Comt+), ComtB2i mice show higher Comt mRNA and enzymatic activity levels. Here, we investigated the molecular genetic mechanisms underlying this allelic specific regulation of Comt expression. Insertion of the B2 element introduces an early polyadenylation signal generating a shorter Comt transcript, in addition to the longer ancestral mRNA. Comparative analysis and in silico prediction of Comt mRNA potential targets within the transcript 3′ to the B2 element was performed and allowed choosing microRNA (miRNA) candidates for experimental screening: mmu-miR-3470a, mmu-miR-3470b, and mmu-miR-667. Cell transfection with each miRNA downregulated the expression of the ancestral transcript and COMT enzymatic activity. Our in vivo experiments showed that mmu-miR-667-3p is strongly correlated with decreasing amounts of Comt mRNA in the brain, and lentiviral injections of mmu-miR-3470a, mmu-miR-3470b, and mmu-miR-667 increase hypersensitivity in the mouse formalin model, consistent with reduced COMT activity. In summary, our data demonstrate that the Comt+ transcript contains regulatory miRNA signals in its 3′-untranslated region leading to mRNA degradation; these signals, however, are absent in the shorter transcript, resulting in higher mRNA expression and activity levels
Mind Perception: Real but Not Artificial Faces Sustain Neural Activity beyond the N170/VPP
Faces are visual objects that hold special significance as the icons of other minds. Previous researchers using event-related potentials (ERPs) have found that faces are uniquely associated with an increased N170/vertex positive potential (VPP) and a more sustained frontal positivity. Here, we examined the processing of faces as objects vs. faces as cues to minds by contrasting images of faces possessing minds (human faces), faces lacking minds (doll faces), and non-face objects (i.e., clocks). Although both doll and human faces were associated with an increased N170/VPP from 175–200 ms following stimulus onset, only human faces were associated with a sustained positivity beyond 400 ms. Our data suggest that the N170/VPP reflects the object-based processing of faces, whether of dolls or humans; on the other hand, the later positivity appears to uniquely index the processing of human faces—which are more salient and convey information about identity and the presence of other minds
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