1,563 research outputs found

    Higher Twist Effects in Deep Inelastic Scattering on Nuclei

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    Particle production in deep inelastic scattering on nuclei is reduced due to absorption of the produced particles in the nucleus. The photon ejects a quark from a bound nucleon which propagates through the nucleus forming a prehadron before turning into a hadron. We calculate the higher twist effect in hadronization which dominates the z1z \to 1 region of fragmentation.Comment: Based on a talk given by H.J. Pirner at the Fifth International Conference on Perspectives in Hadronic Physics, Trieste, May 200

    CD73 represses pro-inflammatory responses in human endothelial cells

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    <p>Abstract</p> <p>Background</p> <p>CD73 is a 5'-ectonucleotidase that produces extracellular adenosine, which then acts on G protein-coupled purigenic receptors to induce cellular responses. CD73 has been reported to regulate expression of pro-inflammatory molecules in mouse endothelium. Our aim is to determine the function of CD73 in human endothelial cells.</p> <p>Methods</p> <p>We used RNAi to deplete CD73 levels in human umbilical cord endothelial cells (HUVECs).</p> <p>Results</p> <p>CD73 depletion resulted in a strong reduction in adenosine production, indicating that CD73 is the major source of extracellular adenosine in HUVECs. We find that CD73 depletion induces a similar response to pro-inflammatory stimuli such as the cytokine TNF-α. In CD73-depleted cells, surface levels of the leukocyte adhesion molecules ICAM-1, VCAM-1 and E-selectin increase. This correlates with increased translocation of the transcription factor NF-kB to the nucleus, which is known to regulate ICAM-1, VCAM-1 and E-selectin expression in response to TNF-α. Adhesion of monocytic cells to endothelial cells is enhanced. In addition, CD73-depleted cells become elongated, have higher levels of stress fibres and increased endothelial permeability, resembling known responses to TNF-α.</p> <p>Conclusions</p> <p>These results indicate that CD73 normally suppresses pro-inflammatory responses in human endothelial cells.</p

    New strategy, new accountability? The European Central Bank and the European Parliament after the strategy review

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    A striking asymmetry defines the European Central Bank (ECB)’s approach to democratic accountability. Although the post-2008 era saw the ECB move dramatically beyond the narrow role envisaged for it by the 1992 Maastricht Treaty, the central bank has continued to hew closely to its scarce accountability provisions.This article documents the much more complex and discretionary nature of today’s ECB policymaking by comparing the frameworks informing Governing Council deliberations according to the 1998, 2003 and 2021 strategies. It shows that the transformation of the ECB’s monetary policy strategy has not been matched with enhanced accountability arrangements between the ECB and the European Parliament. The article concludes with ambitious, but concrete policy proposals – both in substance and form – for new ways of informing the public about monetary policy, instruments to improve accountability and coordinating monetary policy with other European policymakers

    Quartet compatibility and the quartet graph

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    A collection P of leaf-labelled trees is compatible if there exists a single leaf-labelled tree that displays each of the trees in P. Despite its difficulty, determining the compatibility of P is a fundamental task in evolutionary biology. Attractive characterizations in terms of chordal graphs have been previously given for this problem as well as for the problems of (i) determining if there is a unique tree that displays each of the trees in P, that is 'P is definitive and (ii) determining if there is a tree that displays P and has the property that every other tree that displays P is a refinement of it, that is 'P identifies a leaf-labelled tree. In this paper, we describe new characterizations of each of these problems in terms of edge colourings. Furthermore, for an arbitrary leaf-labelled tree 'T, we also determine the minimum number of 'quartets' required to identify 'T, thus correcting a previously published result

    The Martini Model in Materials Science

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    The Martini model, a coarse-grained force field initially developed with biomolecular simulations in mind, has found an increasing number of applications in the field of soft materials science. The model's underlying building block principle does not pose restrictions on its application beyond biomolecular systems. Here, the main applications to date of the Martini model in materials science are highlighted, and a perspective for the future developments in this field is given, particularly in light of recent developments such as the new version of the model, Martini 3

    Audit of healthcare provision for UK prisoners with suspected epilepsy

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    SummaryPurposeTo describe the prevalence and nature of epileptic seizure disorders in a typical UK prison and compare the care offered to prisoners to the recommendations of the National Institute for Clinical Excellence (NICE).MethodsOver a 14-month period, all prisoners identified as having epilepsy were registered by prison primary healthcare services at a category ‘C’ prison holding 640 male adults. Prison and National Health Service health records were reviewed, prisoners were re-assessed by members of a specialist secondary care service based in the local general hospital NHS.ResultsTwenty-six prisoners were thought to have epilepsy. 61.5% of diagnoses had not been made by epilepsy specialists, 73.1% had uncontrolled seizures, only 19.2% had had computed tomography, none magnetic resonance imaging. At review, 30.8% of prisoners were thought to require neuroimaging, 19.2% cardiac investigations. The diagnosis of epilepsy was confirmed in only 57.9% of those prisoners considered to have the condition by prison healthcare services. 53.8% of those prisoners confirmed as having epilepsy had not had a medical review in the past 12 months; 63.2% required a change in their antiepileptic drugs (AEDs).ConclusionAlthough the prevalence of epilepsy in this prison population appeared high at first sight, a critical review of the diagnoses reduced the difference to the prevalence of epilepsy in the population at large. Fewer prisoners than expected achieved seizure control. Collaboration with specialist epilepsy services was poor. There were significant discrepancies between the healthcare provision in prison and the NICE epilepsy guidelines

    The Eliashberg Function of Amorphous Metals

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    A connection is proposed between the anomalous thermal transport properties of amorphous solids and the low-frequency behavior of the Eliashberg function. By means of a model calculation we show that the size and frequency dependence of the phonon mean-free-path that has been extracted from measurements of the thermal conductivity in amorphous solids leads to a sizeable linear region in the Eliashberg function at small frequencies. Quantitative comparison with recent experiments gives very good agreement.Comment: 4pp., REVTeX, 1 uuencoded ps fig. Original posting had a corrupted raw ps fig appended. Published as PRB 51, 689 (1995

    pH-Dependent Conformational Switch Impacts Stability of the PsbS Dimer

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    [Image: see text] The photosystem II PsbS protein triggers the photoprotective mechanism of plants by sensing the acidification of the thylakoid lumen. Despite the mechanism of action of PsbS would require a pH-dependent monomerization of the dimeric form, a clear connection between the pH-induced structural changes and the dimer stability is missing. Here, by applying constant pH coarse-grained and all-atom molecular dynamics simulations, we investigate the pH-dependent structural response of the PsbS dimer. We find that the pH variation leads to structural changes in the lumen-exposed helices, located at the dimeric interface, providing an effective switch between PsbS inactive and active form. Moreover, the monomerization free energies reveal that in the neutral pH conformation, where the network of H-bond interactions at the dimeric interface is destroyed, the protein–protein interaction is weaker. Our results show how the pH-dependent conformations of PsbS affect their dimerization propensity, which is at the basis of the photoprotective mechanism
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