2,466 research outputs found

    A Study of Time and Labour Use on Irish Suckler Beef Farms

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    End of project reportLabour is one of the four factors of production and an increasingly costly and scarce input on farms. The attractiveness of non-farming employment, the nature of farm work and the price received for farm outputs are resulting in falling levels of hired and family labour

    The Workers' Compensation System of British Columbia: Still in Transition

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    This inventory addresses eight core issues in the British Columbia workers' compensation system:* How is the system administered?* How do claims flow through the system?* What dispute resolution procedures are used, and to what effect?* What benefits are paid?* How are vocational rehabilitation services provided?* How is the system financed?* What are the actual costs of administration, benefits, claims processing, and appeal?* What aspects of the system deserve further attention

    An Analysis of the Broadband (22-3900 MHz) Radio Spectrum of HB3 (G132.7+1.3): The Detection of Thermal Radio Emission from an Evolved Supernova Remnant?

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    We present an analysis of the broadband radio spectrum (from 22 to 3900 MHz) of the Galactic supernova remnant (SNR) HB3 (G132.7+1.3). Published observations have revealed that a curvature is present in the radio spectrum of this SNR, indicating that a single synchrotron component appears is insufficient to adequately fit the spectrum. We present here a fit to this spectrum using a combination of a synchrotron component and a thermal bremsstrahlung component. We discuss properties of this latter component and estimate the ambient density implied by the presence of this component to be n \~ 10 cm^-3. We have also analyzed extracted X-ray spectra from archived {\it ASCA} GIS observations of different regions of HB3 to obtain independent estimates of the density of the surrounding interstellar medium (ISM). From this analysis, we have derived electron densities of 0.1-0.4 f^-1/2 cm^-3 for the ISM for the three different regions of the SNR, where f is the volume filling factor. By comparing these density estimates with the estimate derived from the thermal bremsstrahlung component, we argue that the radio thermal bremsstrahlung emission is emitted from a thin shell enclosing HB3. The presence of this thermal bremsstrahlung component in the radio spectrum of HB3 suggests that this SNR is in fact interacting with an adjacent molecular cloud associated with the HII region W3. By extension, we argue that the presence of thermal emission at radio wavelengths may be a useful tool for identifying interactions between SNRs and molecular clouds, and for estimating the ambient density near SNRs using radio continuum data.Comment: 5 pages, 2 figures, accepted for ApJ

    Light Curves for Rapidly-Rotating Neutron Stars

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    We present raytracing computations for light emitted from the surface of a rapidly-rotating neutron star in order to construct light curves for X-ray pulsars and bursters. These calculations are for realistic models of rapidly-rotating neutron stars which take into account both the correct exterior metric and the oblate shape of the star. We find that the most important effect arising from rotation comes from the oblate shape of the rotating star. We find that approximating a rotating neutron star as a sphere introduces serious errors in fitted values of the star's radius and mass if the rotation rate is very large. However, in most cases acceptable fits to the ratio M/R can be obtained with the spherical approximation.Comment: Accepted by the Astrophysical Journal. 13 pages & 7 figure

    Spinning compact binary inspiral II: Conservative angular dynamics

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    We establish the evolution equations of the set of independent variables characterizing the 2PN rigorous conservative dynamics of a spinning compact binary, with the inclusion of the leading order spin-orbit, spin-spin and mass quadrupole - mass monopole effects, for generic (noncircular, nonspherical) orbits. More specifically, we give a closed system of first order ordinary differential equations for the orbital elements of the osculating ellipse and for the angles characterizing the spin orientations with respect to the osculating orbit. We also prove that (i) the relative angle of the spins stays constant for equal mass black holes, irrespective of their orientation, and (ii) the special configuration of equal mass black holes with equal, but antialigned spins, both laying in the plane of motion (leading to the largest recoil found in numerical simulations) is preserved at 2PN level of accuracy, with leading order spin-orbit, spin-spin and mass quadrupolar contributions included.Comment: v2: 19 pages, extended, improved, published versio

    New lambda6cm observations of the Cygnus Loop

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    Radio continuum and polarization observations of the entire Cygnus Loop at 6cm wavelength were made with the Urumqi 25m telescope. The 6cm map is analysed together with recently published maps from the Effelsberg 100m telescope at 21cm and 11cm. The integrated flux density of the Cygnus Loop at 6cm is 90+/-9Jy, which implies a spectral index of -0.40+/-0.06 being consistent with that of Uyaniker et al. (2004) in the wavelength range up to 11cm. This rules out any global spectral steepening up to 6cm. However, small spectral index variations in some regions of the source are possible, but there are no indications for any spectral curvature. The linear polarization data at 6cm show percentage polarizations up to 35% in some areas of the Cygnus Loop, exceeding those observed at 11cm. The Rotation Measure is around -21rad/m^2 in the southern area, which agrees with previous observations. However, the distribution of Rotation Measures is rather complex in the northern part of the Cygnus Loop, where the 21cm emission is totally depolarized. Rotation Measures based on 11cm and 6cm data are significantly larger than in the southern part. The difference in the polarization characteristic between the northern and southern part supports previous ideas that the Cygnus Loop consists of two supernova remnants.Comment: 11 pages, 10 figures, accepted for publication in A&
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