783 research outputs found

    Patterning of ultrathin YBCO nanowires using a new focused-ion-beam process

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    Manufacturing superconducting circuits out of ultrathin films is a challenging task when it comes to patterning complex compounds, which are likely to be deteriorated by the patterning process. With the purpose of developing high-Tc_c superconducting photon detectors, we designed a novel route to pattern ultrathin YBCO films down to the nanometric scale. We believe that our method, based on a specific use of a focused-ion beam, consists in locally implanting Ga^{3+} ions and/or defects instead of etching the film. This protocol could be of interest to engineer high-Tc_c superconducting devices (SQUIDS, SIS/SIN junctions and Josephson junctions), as well as to treat other sensitive compounds.Comment: 13 pages, 7 figure

    Aplicación de las técnicas de suavizado en la variación negativa contingente (CNV)

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    El presente trabajo recoge de forma breve laproblemática de la estimación de la serial en series temporales de datos obtenidos en registros ERP. Se centra en aquellos componentes de frecuencia mis baja, como es el caso de la CNV: Sepropone la utilización alternativa de las técnicas de suavizado del Análisis Exploratorio de Datos (EDA), para mejorar la estimación obtenida, en comparación con la técnica del promediado simple de diferentes ensayos

    Electric-Field Tuning of Spin-Dependent Exciton-Exciton Interactions in Coupled Quantum Wells

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    We have shown experimentally that an electric field decreases the energy separation between the two components of a dense spin-polarized exciton gas in a coupled double quantum well, from a maximum splitting of ∼4\sim 4 meV to zero, at a field of ∼\sim 35 kV/cm. This decrease, due to the field-induced deformation of the exciton wavefunction, is explained by an existing calculation of the change in the spin-dependent exciton-exciton interaction with the electron-hole separation. However, a new theory that considers the modification of screening with that separation is needed to account for the observed dependence on excitation power of the individual energies of the two exciton components.Comment: 5 pages, 4 eps figures, RevTeX, Physical Review Letters (in press

    Development of the Surgical Patient safety Observation Tool (SPOT)

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    Background: A Surgical Patient safety Observation Tool (SPOT) was developed and tested in a multicentre observational pilot study. The tool enables monitoring and benchmarking perioperative safety performance across departments and hospitals, covering international patient safety goals. Methods: Nineteen perioperative patient safety observation topics were selected from Dutch perioperative patient safety guidelines, which also cover international patient safety goals. All items that measured these selected topics were then extracted from available local observation checklists of the participating hospitals. Experts individually prioritized the best measurement items per topic in an initial written Delphi round. The second (face to face) Delphi round resulted in consensus on the content of SPOT, after which the measurable elements (MEs) per topic were defined. Finally, the tool was piloted in eight hospitals for measurability, applicability, improvement potential, discriminatory capacity and feasibility. Results: The pilot test showed good measurability for all 19 patient safety topics (range of 8-291 MEs among topics), with good applicability (median 97 (range 11.8-100) per cent). The overall improvement potential appeared to be good (median 89 (range 72.5-100) per cent), and at topic level the tool showed good discriminatory capacity (variation 27.5 per cent, range in compliance 72.5-100 per cent). Overall scores showed relatively little variation between the participating hospitals (variation 13 per cent, range in compliance 83-96 per cent). All eight auditors considered SPOT a straightforward and easy-to-use tracer tool. Conclusion: A comprehensive tool to measure safety of care was developed and validated using a systematic, stepwise method, enabling hospitals to monitor, benchmark and improve perioperative safety performance

    Eddington-limited X-ray Bursts as Distance Indicators. I. Systematic Trends and Spherical Symmetry in Bursts from 4U 1728-34

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    We investigate the limitations of thermonuclear X-ray bursts as a distance indicator for the weakly-magnetized accreting neutron star 4U 1728-34. We measured the unabsorbed peak flux of 81 bursts in public data from the Rossi X-Ray Timing Explorer (RXTE). The distribution of peak fluxes was bimodal: 66 bursts exhibited photospheric radius expansion and were distributed about a mean bolometric flux of 9.2e-8 erg/cm^2/s, while the remaining (non-radius expansion) bursts reached 4.5e-8 erg/cm^2/s, on average. The peak fluxes of the radius-expansion bursts were not constant, exhibiting a standard deviation of 9.4% and a total variation of 46%. These bursts showed significant correlations between their peak flux and the X-ray colors of the persistent emission immediately prior to the burst. We also found evidence for quasi-periodic variation of the peak fluxes of radius-expansion bursts, with a time scale of approximately 40 d. The persistent flux observed with RXTE/ASM over 5.8 yr exhibited quasi-periodic variability on a similar time scale. We suggest that these variations may have a common origin in reflection from a warped accretion disk. Once the systematic variation of the peak burst fluxes is subtracted, the residual scatter is only approximately 3%, roughly consistent with the measurement uncertainties. The narrowness of this distribution strongly suggests that i) the radiation from the neutron star atmosphere during radius-expansion episodes is nearly spherically symmetric, and ii) the radius-expansion bursts reach a common peak flux which may be interpreted as a standard candle intensity.Adopting the minimum peak flux for the radius-expansion bursts as the Eddington flux limit, we derive a distance for the source of 4.4-4.8 kpc.Comment: 9 pages, 7 figures, accepted by ApJ. Minor referee's revisions, also includes 9 newly public X-ray burst

    P2Y12 blocker monotherapy after percutaneous coronary intervention

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    For secondary prevention of coronary artery disease (CAD) antiplatelet therapy is essential. For patients undergoing a percutaneous coronary intervention (PCI) temporary dual antiplatelet platelet therapy (DAPT: aspirin combined with a P2Y12 blocker) is mandatory, but leads to more bleeding than single antiplatelet therapy with aspirin. Therefore, to reduce bleeding after a PCI the duration of DAPT is usually kept as short as clinically acceptable; thereafter aspirin monotherapy is administered. Another option to reduce bleeding is to discontinue aspirin at the time of DAPT cessation and thereafter to administer P2Y12 blocker monotherapy. To date, five randomised trials have been published comparing DAPT with P2Y12 blocker monotherapy in 32,181 stented patients. Also two meta-analyses addressing this novel therapy have been presented. P2Y12 blocker monotherapy showed a 50-60% reduction in major bleeding when compared to DAPT without a significant increase in ischaemic outcomes, including stent thrombosis. This survey reviews the findings in the current literature concerning P2Y12 blocker monotherapy after PCI

    Topology of six degrees of freedom magnetic bearing

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    A novel magnetic topology has been designed for a six degrees of freedom, magnetically levitated and driven mirror, to be used in a three dimensional (3D) measurement system based on laser interferometry. The translations of the mirror are to be kept small, whereas the rotations are to be controlled over a large range with a high bandwidth and high accuracy. Finite element modelling (FEM) is used to analyze the proposed topology. For computational load reduction, a 2D FEM model has been derived from the actual 3D topology, which incorporates most of the magnetic subsystems. Simulations show that cross-influence between the actuators is small, that the forces and torques are proportional to the applied currents and that the angle of the rotor is of little influence. This allows the multiple in multiple out system to be regarded as multiple linear single in single out systems. ©2000 American Institute of Physics

    Increased adherence to perioperative safety guidelines associated with improved patient safety outcomes:a stepped-wedge, cluster-randomised multicentre trial

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    Background: National Dutch guidelines have been introduced to improve suboptimal perioperative care. A multifaceted implementation programme (IMPlementatie Richtlijnen Operatieve VEiligheid [IMPROVE]) has been developed to support hospitals in applying these guidelines. This study evaluated the effectiveness of IMPROVE on guideline adherence and the association between guideline adherence and patient safety. Methods: Nine hospitals participated in this unblinded, superiority, stepped-wedge, cluster RCT in patients with major noncardiac surgery (mortality risk >= 1%). IMPROVE consisted of educational activities, audit and feedback, reminders, organisational, team-directed, and patient-mediated activities. The primary outcome of the study was guideline adherence measured by nine patient safety indicators on the process (stop moments from the composite STOP bundle, and timely administration of antibiotics) and on the structure of perioperative care. Secondary safety outcomes included in-hospital complications, postoperative wound infections, mortality, length of hospital stay, and unplanned care. Results: Data were analysed for 1934 patients. The IMPROVE programme improved one stop moment: 'discharge from recovery room' (+16%; 95% confidence interval [CI], 9-23%). This stop moment was related to decreased mortality (-3%; 95% CI, -4% to -1%), fewer complications (-8%; 95% CI, -13% to -3%), and fewer unscheduled transfers to the ICU (-6%; 95% CI, -9% to -3%). IMPROVE negatively affected one other stop moment - 'discharge from the hospital' - possibly because of the limited resources of hospitals to improve all stop moments together. Conclusions: Mixed implementation effects of IMPROVE were found. We found some positive associations between guideline adherence and patient safety (i.e. mortality, complications, and unscheduled transfers to the ICU) except for the timely administration of antibiotics

    Are Bad Leaders Indeed Bad for Employees? A Meta-Analysis of Longitudinal Studies Between Destructive Leadership and Employee Outcomes

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    Does having bad leaders have long-lasting adverse effects on employees? While previous studies have primarily viewed subordinate deviant behavior as a crucial consequence of destructive leadership, aggression theory suggests that subordinate deviant behavior could also be an antecedent of destructive leadership. To address this question, we conducted a meta-analysis by focusing on longitudinal field studies (i.e., time-lagged and panel designs), and investigated the longitudinal associations as well as the reciprocal relationships between destructive leadership and employee outcomes. Results from 82 articles with 104 independent prospective and longitudinal studies (N = 30,314) showed that destructive leadership has a lagged detrimental impact on employee behavioral (e.g., OCB, workplace deviance, CWB, and avoidance) and attitudinal outcomes (e.g., job satisfaction and work commitment). There are no significant differences between destructive leadership and employee outcomes for the long-term and short-term effects. Surprisingly, after accounting for auto-regression effects, the cross-lagged analysis showed that destructive leadership did not significantly relate to employees’ negative behavior over time, whereas negative employee behavior did relate to destructive leadership across time. Theoretical and practical implications are discussed
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