1,061 research outputs found

    The 3^3He(e, e'd)p Reaction in qω\omega-constant Kinematics

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    The cross section for the 3^3He(e, e'd)p reaction has been measured as a function of the missing momentum pmp_m in qω\omega -constant kinematics at beam energies of 370 and 576 MeV for values of the three-momentum transfer qq of 412, 504 and 604 \mevc. The L(+TT), T and LT structure functions have been separated for qq = 412 and 504 \mevc. The data are compared to three-body Faddeev calculations, including meson-exchange currents (MEC), and to calculations based on a covariant diagrammatic expansion. The influence of final-state interactions and meson-exchange currents is discussed. The pmp_m-dependence of the data is reasonably well described by all calculations. However, the most advanced Faddeev calculations, which employ the AV18 nucleon-nucleon interaction and include MEC, overestimate the measured cross sections, especially the longitudinal part, and at the larger values of qq. The diagrammatic approach gives a fair description of the cross section, but under(over)estimates the longitudinal (transverse) structure function.Comment: 17 pages, 7 figure

    A Bipolar Spindle of Antiparallel ParM Filaments Drives Bacterial Plasmid Segregation

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    To ensure their stable inheritance by daughter cells during cell division, bacterial low copy-number plasmids make simple DNA segregating machines that use an elongating protein filament between sister plasmids. In the ParMRC system of Escherichia coli R1 plasmid, ParM, an actin-like protein, forms the spindle between ParRC complexes on sister plasmids. Using a combination of structural work and total internal reflection fluorescence microscopy, we show that ParRC bound and could accelerate growth at only one end of polar ParM filaments, mechanistically resembling eukaryotic formins. The architecture of ParM filaments enabled two ParRC-bound filaments to associate in an antiparallel orientation, forming a bipolar spindle. The spindle elongated as a bundle of at least two antiparallel filaments, thereby pushing two plasmid clusters towards the poles

    The 4^4He(e,ep)(e,e'p) Cross Section at Large Missing Energy

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    The (e,ep)(e,e'p) reaction on 4He^{4}{He} nuclei was studied in kinematics designed to emphasize effects of nuclear short-range correlations. The measured cross sections display a peak in the kinematical regions where two-nucleon processes are expected to dominate. Theoretical models incorporating short-range correlation effects agree reasonably with the data.Comment: 4 pages LaTeX, using espcrc1.sty and wrapfig.sty (included), two figures. Talk presented by J. Templon at the 15th Int. Conf. on Few-Body Problems in Physics, Groningen, The Netherlands, 22-26 July, 199

    Conventional hemodynamic resuscitation may fail to optimize tissue perfusion: An observational study on the effects of dobutamine, enoximone, and norepinephrine in patients with acute myocardial infarction complicated by cardiogenic shock

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    Aim: To investigate the effects of inotropic agents on parameters of tissue perfusion in patients with cardiogenic shock. Methods and Results: Thirty patients with cardiogenic shock were included. Patients received dobutamine, enoximone, or norepinephrine. We performed hemodynamic measurements at baseline and after titration of the inotropic agent until cardiac index (CI) ≥2.5 L.min-1.m-2 or mixed-venous oxygen saturation (SvO 2) ≥70% (dobutamine or enoximone), and mean arterial pressure (MAP) ≥70 mmHg (norepinephrine). As parameters of tissue perfusion, we measured central-peripheral temperature gradient (delta-T) and sublingual perfused capillary density (PCD). All patients reached predefined therapeutic targets. The inotropes did not significantly change delta-T. Dobutamine did not change PCD. Enoximone increased PCD (9.1 [8.9-10.2] vs. 11.4 [8.4-13.9] mm.mm-2; p10.3 mm.mm-2; mortality 72% vs. 17%, p = 0.003). Conclusion: This study demonstrates the effects of commonly used inotropic agents on parameters of tissue perfusion in patients with cardiogenic shock. Despite hemodynamic optimization, tissue perfusion was not sufficiently restored in most patients. In these patients, mortality was high. Interventions directed at improving microcirculation may eventually help bridging the gap between improved hemodynamics and dismal patient outcome in cardiogenic shock

    Embedded systemen : vooroplopen in moordende concurrentie

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    Embedded systemen bestaan uit hardware en software en sluiten 100 procent aan bij de topsector High Tech Systemen en Materialen. Software engineering is essentieel voor embedded systemen – en we blinken er in uit,’ zegt Mark van den Brand van de TU Eindhoven naar aanleiding van het hoofdstuk How can embedded systems make our environment smart? uit The scientific answer to the roadmap ICT for the top sectors. Door Leendert van der En

    Embedded systemen : vooroplopen in moordende concurrentie

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    Embedded systemen bestaan uit hardware en software en sluiten 100 procent aan bij de topsector High Tech Systemen en Materialen. Software engineering is essentieel voor embedded systemen – en we blinken er in uit,’ zegt Mark van den Brand van de TU Eindhoven naar aanleiding van het hoofdstuk How can embedded systems make our environment smart? uit The scientific answer to the roadmap ICT for the top sectors. Door Leendert van der En

    Tensor Analyzing Powers for Quasi-Elastic Electron Scattering from Deuterium

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    We report on a first measurement of tensor analyzing powers in quasi-elastic electron-deuteron scattering at an average three-momentum transfer of 1.7 fm1^{-1}. Data sensitive to the spin-dependent nucleon density in the deuteron were obtained for missing momenta up to 150 MeV/cc with a tensor polarized 2^2H target internal to an electron storage ring. The data are well described by a calculation that includes the effects of final-state interaction, meson-exchange and isobar currents, and leading-order relativistic contributions.Comment: 4 pages, 3 figure

    Nucleocytoplasmic human O-GlcNAc transferase is sufficient for O-GlcNAcylation of mitochondrial proteins

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    O-linked N-acetylglucosamine modification (O-GlcNAcylation) is a nutrient-dependent protein post-translational modification (PTM), dynamically and reversibly driven by two enzymes: O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA) that catalyse the addition and the removal of the O-GlcNAc moieties to/from serine and threonine residues of target proteins respectively. Increasing evidence suggests involvement of O-GlcNAcylation in many biological processes, including transcription, signalling, neuronal development and mitochondrial function. The presence of a mitochondrial O-GlcNAc proteome and a mitochondrial OGT (mOGT) isoform has been reported. We explored the presence of mOGT in human cell lines and mouse tissues. Surprisingly, analysis of genomic sequences indicates that this isoform cannot be expressed in most of the species analysed, except some primates. In addition, we were not able to detect endogenous mOGT in a range of human cell lines. Knockdown experiments and Western blot analysis of all the predicted OGT isoforms suggested the expression of only a single OGT isoform. In agreement with this, we demonstrate that overexpression of the nucleocytoplasmic OGT (ncOGT) isoform leads to increased O-GlcNAcylation of mitochondrial proteins, suggesting that ncOGT is necessary and sufficient for the generation of the O-GlcNAc mitochondrial proteome

    Examining conscientiousness as a key resource in resisting email interruptions : implications for volatile resources and goal achievement

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    Within the context of the conservation of resources model, when a resource is deployed, it is depleted - albeit temporarily. However, when a 'key', stable resource, such as Conscientiousness, is activated (e.g., using a self-control strategy, such as resisting an email interruption), we predicted that (1) another, more volatile resource (affective well-being) would be impacted and that (2) this strategy would be deployed as a trade-off, allowing one to satisfy task goals, at the expense of well-being goals. We conducted an experience‐sampling field study with 52 email-users dealing with their normal email as it interrupted them over the course of a half‐day period. This amounted to a total of 376 email reported across the sample. Results were analysed using random coefficient hierarchical linear modelling and included cross-level interactions for Conscientiousness with strategy and well-being. Our first prediction was supported - deploying the stable, key resource of Conscientiousness depletes the volatile, fluctuating resource of affective well-being. However, our second prediction was not fully realized. Although resisting or avoiding an email interruption was perceived to hinder well-being goal achievement by Conscientious people, it had neither a positive nor negative impact on task goal achievement. Implications for theory and practice are discussed. Practitioner points: It may be necessary for highly Conscientious people to turn off their email interruption alerts at work, in order to avoid the strain that results from an activation-resistance mechanism afforded by the arrival of a new email. Deploying key resources means that volatile resources may be differentially spent, depending on one's natural tendencies and how these interact with the work task and context. This suggests that the relationship between demands and resources is not always direct and predictable. Practitioners may wish to appraise the strategies they use to deal with demands such as email at work, to identify if these strategies are assisting with task or well-being goal achievement, or whether they have become defunct through automation
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