13,923 research outputs found

    The first experimental flight package of an advanced telemetry system with adaptive capability Technical summary report, 1 Jul. 1963 - 15 Feb. 1965

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    Mechanical design, and environmental and functional testing of advanced telemetry system flight package with adaptive capabilit

    A relativistically covariant version of Bohm's quantum field theory for the scalar field

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    We give a relativistically covariant, wave-functional formulation of Bohm's quantum field theory for the scalar field based on a general foliation of space-time by space-like hypersurfaces. The wave functional, which guides the evolution of the field, is space-time-foliation independent but the field itself is not. Hence, in order to have a theory in which the field may be considered a beable, some extra rule must be given to determine the foliation. We suggest one such rule based on the eigen vectors of the energy-momentum tensor of the field itself.Comment: 1 figure. Submitted to J Phys A. 20/05/04 replacement has additional references and a few minor changes made for clarity. Accepted by J Phys

    Impacts of the living wage on in-work poverty

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    As low pay and in-work poverty have proliferated, demands for a higher, ‘living wage’, have gathered strength in countries such as the US and UK. Two decades since the first modern living wage campaign succeeded in Baltimore, a vibrant movement is challenging low pay across the US. In the UK, the government announced a ‘national living wage’ in 2015. This chapter reviews the efficacy of the living wage as a means of tackling in-work poverty. It begins by examining the extent to which low pay is a cause of household poverty, before explaining how living wages are calculated and briefly outlining the history of the movement. It then summarizes existing research on the impact of living wages on poverty and employment, as well the potential consequences of scaling up the living wage. The politics of the living wage are explored. The concept has served to mobilize broad coalitions of labour and community groups to challenge the marginalization of low-paid workers. However, the living wage also raises questions about where responsibility lies for tackling in-work poverty. Lastly, the chapter considers what future direction the living wage movement might take in order to make a greater impact on in-work poverty

    Penetration And Scattering Of Lower Hybrid Waves By Density Fluctuations

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    Lower Hybrid [LH] ray propagation in toroidal plasma is controlled by a combination of the azimuthal spectrum launched from the antenna, the poloidal variation of the magnetic field, and the scattering of the waves by the density fluctuations. The width of the poloidal and radial RF wave spectrum increases rapidly as the rays penetrate into higher density and scatter from the turbulence. The electron temperature gradient [ETG] spectrum is particularly effective in scattering the LH waves due to its comparable wavelengths and parallel phase velocities. ETG turbulence is also driven by the radial gradient of the electron current density giving rise to an anomalous viscosity spreading the LH-driven plasma currents. The scattered LH spectrum is derived from a Fokker-Planck equation for the distribution of the ray trajectories with a diffusivity proportional to the fluctuations. The LH ray diffusivity is large giving transport in the poloidal and radial wavenumber spectrum in one -or a few passes - of the rays through the core plasma.Institute for Fusion Studie

    Shuttle/spacelab MMAP/electromagnetic environment experiment phase B definition study

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    Progress made during the first five months of the Phase B definition study for the MMAP/Electromagnetic Environment Experiment (EEE) was described. An antenna/receiver assembly has been defined and sized for stowing in a three pallet bay area in the shuttle. Six scanning modes for the assembly are analyzed and footprints for various antenna sizes are plotted. Mission profiles have been outlined for a 400 km height, 57 deg inclination angle, circular orbit. Viewing time over 7 geographical areas are listed. Shuttle interfaces have been studied to determine what configuration the antenna assembly must have to be shared with other experiments of the Microwave Multi-Applications Payload (MMAP) and to be stowed in the shuttle bay. Other results reported include a frequency plan, a proposed antenna subsystem design, a proposed receiver design, preliminary outlines of the experiment controls and an analysis of on-board and ground data processing schemes

    Instruments without optics: an integrated photonic spectrograph

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    In recent years, a great deal of emphasis has been placed on achieving the diffraction limit with large aperture telescopes. For a well matched focal-plane instrument, the diffraction limit provides the highest possible angular resolution and sensitivity per pixel. But it offers another key advantage as we now show. Conventionally, as the telescope aperture D grows, the instrument size grows in proportion to D, and cost increases as D^2 or faster. However, an instrument that operates at the diffraction limit can break the trend of spiralling costs. In traditional instruments, the light must pass through a succession of large lenses, mirrors and gratings, making it difficult to conserve the integrity of such as small psf. An alternative approach, as we now show, is to couple the diffraction limited beam directly into an integrated photonic spectrograph operating in low-order modes.Comment: 14 pages, 7 figures, to be published in Proc. SPIE 6269 Ground-based and Airborne Instrumentation for Astronom

    Agrin isoforms and their role in synaptogenesis

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    Agrin is thought to mediate the motor neuron-induced aggregation of synaptic proteins on the surface of muscle fibers at neuromuscular junctions. Recent experiments provide direct evidence in support of this hypothesis, reveal the nature of agrin immunoreactivity at sites other than neuromuscular junctions, and have resulted in findings that are consistent with the possibility that agrin plays a role in synaptogenesis throughout the nervous system
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