21,495 research outputs found

    When is choice a good thing?: An experimental study of the impact of choice on patient outcomes

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    The official published version can be obtained from the link below - Copyright @ Taylor & FrancisAlthough policy emphasises the benefits of choice, an increasing body of work points to times when choice may not always have positive consequences. The present experimental study aimed to explore the impact of choice on a number of patient outcomes in the health care setting. The study also explored the extent to which the influence of choice was affected by patient uncertainty and anticipated regret. Choice was conceptualized as consisting of two dimensions: ‘having choice’ which reflects the availability of a number of options and ‘making choice’ reflecting resolution and a desire for a choice to be made. Consecutive patients (n=427) from 4 General Practices in Surrey were asked to read one of 16 vignettes which varied in terms of 4 independent variables (having choice, making choice, uncertainty, anticipated regret) and to rate items relating to 4 outcome variables (patient satisfaction, perceived control, negative emotions, information seeking). The results showed that having more choice was consistently associated with more positive patient outcomes than having no choice. Having no choice was particularly detrimental for those experiencing anticipated regret and uncertainty. In contrast, whether or not a choice was made had no impact upon any of the outcome measures. In line with current policy having choice in the health care setting is related to improved patient outcomes. The results provide some insights into the factors which influence the direction of the impact of choice. They also indicate the importance of differentiating between ‘having choice’ and ‘making choice’.Funding received from ESRC award: RES-000-22-165

    An analysis of the crossover between local and massive separation on airfoils

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    Massive separation on airfoils operating at high Reynolds number is an important problem to the aerodynamicist, since its onset generally determines the limiting performance of an airfoil, and it can lead to serious problems related to aircraft control as well as turbomachinery operation. The phenomenon of crossover between local separation and massive separation on realistic airfoil geometries induced by airfoil thickness is investigated for low speed (incompressible) flow. The problem is studied both for the asymptotic limit of infinite Reynolds number using triple-deck theory, and for finite Reynolds number using interacting boundary-layer theory. Numerical results are presented which follow the evolution of the flow as it develops from a mildly separated state to one dominated by the massively separated flow structure as the thickness of the airfoil geometry is systematically increased. The effect of turbulence upon the evolution of the flow is considered, and the impact is significant, with the principal effect being the suppression of the onset of separation. Finally, the effect of surface suction and injection for boundary-layer control is considered. The approach which was developed provides a valuable tool for the analysis of boundary-layer separation up to and beyond stall. Another important conclusion is that interacting boundary-layer theory provides an efficient tool for the analysis of the effect of turbulence and boundary-layer control upon separated vicsous flow

    Temperature dependence of the average electron-hole pair creation energy in Al0.8Ga0.2As

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    The temperature dependence of the average energy consumed in the creation of an electron-hole pair in the wide bandgap compound semiconductor Al 0.8Ga0.2As is reported following X-ray measurements made using an Al0.8Ga0.2As photodiode diode coupled to a low-noise charge-sensitive preamplifier operating in spectroscopic photon counting mode. The temperature dependence is reported over the range of 261 K-342 K and is found to be best represented by the equation ε AlGaAs 7.327-0.0077 T, where εAlGaAs is the average electron-hole pair creation energy in eV and T is the temperature in K. © 2013 © 2013 Author(s)

    Retrodiction as a tool for micromaser field measurements

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    We use retrodictive quantum theory to describe cavity field measurements by successive atomic detections in the micromaser. We calculate the state of the micromaser cavity field prior to detection of sequences of atoms in either the excited or ground state, for atoms that are initially prepared in the excited state. This provides the POM elements, which describe such sequences of measurements.Comment: 20 pages, 4(8) figure

    Designing Catastrophe Bonds to Securitize Systemic Risks in Agriculture: The Case of Georgia Cotton

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    This article makes an initial attempt to design catastrophe (CAT) bond products for agriculture and examines the potential of these instruments as mechanisms for transferring agricultural risks from insurance companies to investors/speculators in the global capital market. The case of Georgia cotton is considered as a specific example. The CAT bond contracts are based on percentage deviations of realized state average yields relative to the long-run average. The contracts are priced using historical state-level cotton yield data. The principal finding of the study is that the proposed CAT bonds demonstrate potential as risk transfer mechanisms for crop insurance companies.CAT bonds, catastrophe bond pricing, catastrophe insurance, disaster risk, reinsurance, risk securitization, Risk and Uncertainty,

    Payload deployment method and system

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    A method and apparatus for deploying the payload of space shuttle or the like is described. It is referred to as the Stabilized Payload Deployment System (SPDS). The payload is rotated about an axis outside of the payload but approximately longitudinally with the cargo bay of the shuttle craft. The payload may thus be rotated through ninety degrees. In this case, that is, in its rotated position, the payload may or may not have a small portion located within the cargo bay. Alternatively, the payload may be located completely outside of the bay. According to the apparatus two separable hinge-like devices connect at one longitudinal side or edge of the payload to respective ones of the payload trunnions at different longitudinally spaced locations along the length of the payload. Separation of the payload from the cargo bay is made by unlatching a latch and by the use of a repulsion spring at the position of each hinge-like device. Two four-link mechanisms allow movement between payload and bay. Such accommodative movement is required especially during launch when considerable vibration is encountered

    The influence of free-stream turbulence on separation of turbulent boundary layers in incompressible, two-dimensional flow

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    Experiments were conducted to determine if free-stream turbulence scale affects separation of turbulent boundary layers. In consideration of possible interrelation between scale and intensity of turbulence, the latter characteristic also was varied and its role was evaluated. Flow over a 2-dimensional airfoil in a subsonic wind tunnel was studied with the aid of hot-wire anemometry, liquid-film flow visualization, a Preston tube, and static pressure measurements. Profiles of velocity, relative turbulence intensity, and integral scale in the boundary layer were measured. Detachment boundary was determined for various angles of attack and free-stream turbulence. The free-stream turbulence intensity and scale were found to spread into the entire turbulent boundary layer, but the effect decreased as the airfoil surface was approached. When the changes in stream turbulence were such that the boundary layer velocity profiles were unchanged, detachment location was not significantly affected by the variations of intensity and scale. Pressure distribution remained the key factor in determining detachment location

    Cyclotron motion and magnetic focusing in semiconductor quantum wells with spin-orbit coupling

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    We investigate the ballistic motion of electrons in III-V semiconductor quantum wells with Rashba spin-orbit coupling in a perpendicular magnetic field. Taking into account the full quantum dynamics of the problem, we explore the modifications of classical cyclotron orbits due to spin-orbit interaction. As a result, for electron energies comparable with the cyclotron energy the dynamics are particularly rich and not adequately described by semiclassical approximations. Our study is complementary to previous semiclassical approaches concentrating on the regime of weaker fields.Comment: 14 pages, 8 figures included, version to appear in Phys. Rev.
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