18,908 research outputs found

    A comparison of cognitive function, sleep and activity levels in disease-free breast cancer patients with or without cancer-related fatigue syndrome.

    Get PDF
    Chronic fatigue is a feature in a subset of women successfully treated for breast cancer but is not well characterised. This study examines differences in objective cognitive function, activity levels and sleep in disease-free women who do and do not meet criteria for cancer-related fatigue syndrome (CRFS)

    Developments in aircraft jet noise technology

    Get PDF
    Significant developments in two areas of jet noise technology are described: the development of jet noise technology relative to coannular nozzles of all types, and a recent approach to the analysis of flight effects that appears to allow simulated flight effects results to be transformed to actual flight conditions with a high degree of confidence. The coannular nozzle section presents results applicable to high-bypass-ratio turbofan engines, as well as current work on inverted-profile coannular nozzles applicable to low-bypass-ratio turbofan engines suitable for use in future supersonic cruise aircraft

    Noise of model target type thrust reversers for engine-over-the-wing applications

    Get PDF
    The results of experiments on the noise generated by V-gutter and semicylindrical target reversers with circular and short-aspect-ratio slot nozzles having diameters of about 5 cm are presented. The experiments were conducted with cold-flow jets at velocities from 190-290 m/sec. The reversers at subsonic jet velocities had a more uniform noise distribution and higher frequency than the nozzles alone. The reverser shape was shown to be more important than the nozzle shape in determining the noise characteristics. The maximum sideline pressure level varied with the sixth power of the jet velocity, and the data were correlated for angles along the sideline. An estimate of the noise level along the 152 m sideline for an engine-over-the-wing powered-lift airplane was made

    How Much Help Is Exchanged in Families? Towards an Understanding of Discrepant Research Findings

    Get PDF
    Responding to claims that contemporary families had abandoned their elderly members, gerontologists over the past 30 years have provided extensive documentation of intergenerational familial support. These studies have been lodged within conceptual frameworks of the modified extended family, intergenerational solidarity, and, more recently, intergenerational equity. By and large, studies claim to have found extensive levels of support. Closer examination of findings from various studies, however, reveals widely discrepant findings in terms of amounts of help given to and received by older family members. This paper examines the findings from four representative Canadian and American studies spanning four decades. Factors contributing to discrepant findings are identified at both methodological and conceptual levels, and implications for future research are discussed.intergenerational support

    Status of noise technology for advanced supersonic cruise aircraft

    Get PDF
    Developments in acoustic technology applicable to advanced supersonic cruise aircraft, particularly those which relate to jet noise and its suppression are reviewed. The noise reducing potential of high radius ratio, inverted velocity profile coannular jets is demonstrated by model scale results from a wide range of nozzle geometries, including some simulated flight cases. These results were verified statistically at large scale on a variable cycle engine (VCE) testbed. A preliminary assessment of potential VCE noise sources such as fan and core noise is made, based on the testbed data. Recent advances in the understanding of flight effects are reviewed. The status of component noise prediction methods is assessed on the basis of recent test data, and the remaining problem areas are outlined

    Noise tests of a high-aspect-ratio slot nozzle with various V-gutter target thrust reversers

    Get PDF
    The results of experiments on the noise generated by a 1.33- by 91.4 cm slot nozzle with various V-gutter reversers, and some thrust measurements are presented. The experiments were conducted with near-ambient temperature jets at nozzle pressure ratios of 1.25 to 3.0, yielding jet velocities of about 190 to 400 m/sec. At pressure ratios of 2 or less, the reversers, in addition to being noisier than the nozzle alone, also had a more uniform directional distribution and more high-frequency noise. At pressure ratios above 2, the nozzle alone generated enough shock noise that the levels were about the same as for the reversers. The maximum overall sound pressure level and the effective overall sound power level both varied with the sixth power of jet velocity over the range tested. The data were scaled up to a size suitable for reversing the wing-flap slot nozzle flow of a 45 400-kg augmentor-wing-type airplane on the ground, yielding perceived noise levels well above 95 PNdB on a 152-m sideline

    How Much Help Is Exchanged in Families? Towards an Understanding of Discrepant Research Finding

    Get PDF
    Responding to claims that contemporary families had abandoned their elderly members, gerontologists over the past 30 years have provided extensive documentation of intergenerational familial support. These studies have been lodged within conceptual frameworks of the modified extended family, intergenerational solidarity, and, more recently, intergenerational equity. By and large, studies claim to have found extensive levels of support. Closer examination of findings from various studies, however, reveals widely discrepant findings in terms of amounts of help given to and received by older family members. This paper examines the findings from four representative Canadian and American studies spanning four decades. Factors contributing to discrepant findings are identified at both methodological and conceptual levels, and implications for future research are discussed.intergenerational support

    Magnetic pressure support and accretion disk spectra

    Full text link
    Stellar atmosphere models of ionized accretion disks have generally neglected the contribution of magnetic fields to the vertical hydrostatic support, although magnetic fields are widely believed to play a critical role in the transport of angular momentum. Simulations of magnetorotational turbulence in a vertically stratified shearing box geometry show that magnetic pressure support can be dominant in the upper layers of the disk. We present calculations of accretion disk spectra that include this magnetic pressure support, as well as a vertical dissipation profile based on simulation. Magnetic pressure support generically produces a more vertically extended disk atmosphere with a larger density scale height. This acts to harden the spectrum compared to models that neglect magnetic pressure support. We estimate the significance of this effect on disk-integrated spectra by calculating an illustrative disk model for a stellar mass black hole, assuming that similar magnetic pressure support exists at all radii.Comment: submitted to Ap

    Transmission eigenvalues and the bare conductance in the crossover to Anderson localization

    Full text link
    We measure the field transmission matrix t for microwave radiation propagating through random waveguides in the crossover to Anderson localization. From these measurements, we determine the dimensionless conductance, g, and the individual eigenvalues τn\tau_n of the transmission matrix tttt^\dagger whose sum equals g. In diffusive samples, the highest eigenvalue, τ1\tau_1, is close to unity corresponding to a transmission of nearly 100%, while for localized waves, the average of τ1\tau_1, is nearly equal to g. We find that the spacing between average values of lnτn\ln\tau_n is constant and demonstrate that when surface interactions are taken into account it is equal to the inverse of the bare conductance.Comment: 5 pages, 5 figure

    Quelques nouveaux développements dans l’analyse de la migration interne au Canada

    Get PDF
    corecore