159,709 research outputs found

    Mechanical chest-compression devices: current and future roles

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    Purpose of review: It is recognised that the quality of CPR is an important predictor of outcome from cardiac arrest yet studies consistently demonstrate that the quality of CPR performed in real life is frequently sub-optimal. Mechanical chest compression devices provide an alternative to manual CPR. This review will consider the evidence and current indications for the use of these devices. Recent findings: Physiological and animal data suggest that mechanical chest compression devices are more effective than manual CPR. However there is no high quality evidence showing improved outcomes in humans. There are specific circumstances where it may not be possible to perform manual CPR effectively e.g. during ambulance transport to hospital, en-route to and during cardiac catheterisation, prior to organ donation and during diagnostic imaging where using these devices may be advantageous. Summary: There is insufficient evidence to recommend the routine use of mechanical chest compression devices. There may be specific circumstances when CPR is difficult or impossible where mechanical devices may play an important role in maintaining circulation. There is an urgent need for definitive clinical and cost effectiveness trials to confirm or refute the place of mechanical chest compression devices during resuscitation

    Strongly anharmonic current-phase relation in ballistic graphene Josephson junctions

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    Motivated by a recent experiment directly measuring the current-phase relation (CPR) in graphene under the influence of a superconducting proximity effect, we here study the temperature dependence of the CPR in ballistic graphene SNS Josephson junctions within the the self-consistent tight-binding Bogoliubov-de Gennes (BdG) formalism. By comparing these results with the standard Dirac-BdG method, where rigid boundary conditions are assumed at the SN interfaces, we show on a crucial importance of both proximity effect and depairing by current for the CPR. The proximity effect grows with temperature and reduces the skewness of the CPR towards the harmonic result. In short junctions (L<ξL<\xi) current depairing is also important and gives rise to a critical phase ϕc<π/2\phi_c<\pi/2 over a wide range of temperatures and doping levels.Comment: 7 pages, 4 figures. v2 contains very minor change

    CPR and ECC

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    This practical workshop will demonstrate the following Emergency and Critaickl Care techiques: Cardioplumonary Resuscitation. Thoracocentesis. Intermittent Positive Pressure Ventilation. Delegates will then be provided with the opportunity to practice the techniques themeselves on professional mannequins

    A river basin as a common-pool resource: a case study for the Jaguaribe basin in Brazil

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    Rainfall variability and the associated water stress are of major concern in semi-arid regions subject to conflicts between water users. To achieve sustainable and stable agricultural performance it is necessary to understand\ud the interaction between natural processes and human response. This paper investigates the applicability of common-pool resource (CPR) concepts to understand governance of water resources in semi-arid river basins. This is done by evaluating the governance of water resources in the Jaguaribe basin in the semi-arid Northeast of Brazil. The results show that common-pool resource concepts offer valuable insights for explaining variations in water resource use and availability at the river basin scale. The water system in a river basin can be characterized as one large CPR consisting of asymmetrically linked smaller CPR’s. This study showed that CPR concepts are useful for explaining agricultural productivity, stability and equitability in a semi-arid river basin. The asymmetry of a river basin CPR is the cause of unidirectional externalities towards downstream. The topography, the sequence of rainfall events and distribution of reservoir capacities in a river basin strongly\ud influence the extent to which convergence of resource flow can compensate for these externalities

    Current-phase relations of few-mode InAs nanowire Josephson junctions

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    Gate-tunable semiconductor nanowires with superconducting leads have great potential for quantum computation and as model systems for mesoscopic Josephson junctions. The supercurrent, II, versus the phase, ϕ\phi, across the junction is called the current-phase relation (CPR). It can reveal not only the amplitude of the critical current, but also the number of modes and their transmission. We measured the CPR of many individual InAs nanowire Josephson junctions, one junction at a time. Both the amplitude and shape of the CPR varied between junctions, with small critical currents and skewed CPRs indicating few-mode junctions with high transmissions. In a gate-tunable junction, we found that the CPR varied with gate voltage: Near the onset of supercurrent, we observed behavior consistent with resonant tunneling through a single, highly transmitting mode. The gate dependence is consistent with modeled subband structure that includes an effective tunneling barrier due to an abrupt change in the Fermi level at the boundary of the gate-tuned region. These measurements of skewed, tunable, few-mode CPRs are promising both for applications that require anharmonic junctions and for Majorana readout proposals
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