10,576 research outputs found

    Energy consumption analysis of the Venus Deep Space Station (DSS-13)

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    This report continues the energy consumption analysis and verification study of the tracking stations of the Goldstone Deep Space Communications Complex, and presents an audit of the Venus Deep Space Station (DSS 13). Due to the non-continuous radioastronomy research and development operations at the station, estimations of energy usage were employed in the energy consumption simulation of both the 9-meter and 26-meter antenna buildings. A 17.9% decrease in station energy consumption was experienced over the 1979-1981 years under study. A comparison of the ECP computer simulations and the station's main watt-hour meter readings showed good agreement

    Why will rat's go where rats will not

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    Experimental evidence indicates that regular plurals are nearly always omitted from English compounds (e.g., rats-eater) while irregular plurals may be included within these structures (e.g., mice-chaser). This phenomenon is considered to be good evidence to support the dual mechanism model of morphological processing (Pinker & Prince, 1992). However, evidence from neural net modelling has shown that a single route associative memory based account might provide an equally, if not more, valid explanation of the compounding phenomenon

    Plural morphology in compounding is not good evidence to support the dual mechanism model

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    The compounding phenomena is considered to be good evidence to support the dual mechanism model of morphological processing (Pinker & Prince, 1992). However evidence from initial neural net modeling has shown that a single route associative memory based account might provide an equally, if not more valid explanation of the treatment of plurals in compounds. Further neural net modeling and empirical work is proposed to test this single route accoun

    Effects of Neighbourhood Income on Reported Body Mass Index: An Eight Year Longitudinal Study of Canadian Children

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    Background: This study investigates the effects of neighbourhood income on children\u27s BodyMass Index (BMI) from childhood (ages 2–3) to early adolescence (ages 10–11) using longitudinaldata. Methods: Five cycles of data from the Canadian National Longitudinal Survey of Children andYouth are analyzed for a sub-sample of children (n = 2152) aged 2–3 at baseline (1994) and assessedat two year intervals to 2002. Body mass index percentiles are based on height/weight estimatesreported by proxy respondents (child\u27s person most knowledgeable). Family and neighbourhoodfactors were assessed at baseline. The prevalence of neighbourhood low income was obtained fromthe 1996 Census and divided into three categories from \u27most poor\u27 to \u27least poor\u27. Longitudinalmodelling techniques were applied to the data. Results: After controlling for individual/family factors (age, sex, income, education, familystructure) living in the \u27most poor\u27 neighbourhood was associated with increasing BMI percentile(1.46, 95% CI 0.16 to 2.75) over time compared to a \u27middle\u27 income neighbourhood. Living in anurban (vs. rural) neighbourhood was associated with a decreased BMI percentile (-3.57, 95% CI -6.38 to -0.76) across all time periods. Conclusion: These findings provide evidence that effects of neighbourhood disadvantage onchildren\u27s BMI occur between childhood and early adolescence and suggest that policies shouldtarget the conditions of childhood, including the neighbourhood environment

    Nonlinear propagation of light in Dirac matter

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    The nonlinear interaction between intense laser light and a quantum plasma is modeled by a collective Dirac equation coupled with the Maxwell equations. The model is used to study the nonlinear propagation of relativistically intense laser light in a quantum plasma including the electron spin-1/2 effect. The relativistic effects due to the high-intensity laser light lead, in general, to a downshift of the laser frequency, similar to a classical plasma where the relativistic mass increase leads to self-induced transparency of laser light and other associated effects. The electron spin-1/2 effects lead to a frequency up- or downshift of the electromagnetic (EM) wave, depending on the spin state of the plasma and the polarization of the EM wave. For laboratory solid density plasmas, the spin-1/2 effects on the propagation of light are small, but they may be significant in super-dense plasma in the core of white dwarf stars. We also discuss extensions of the model to include kinetic effects of a distribution of the electrons on the nonlinear propagation of EM waves in a quantum plasma.Comment: 9 pages, 2 figure

    Mount St. Helens aerosol evolution

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    Stratospheric aerosol samples were collected using a wire impactor during the year following the eruption of Mount St. Helens. Analysis of samples shows that aerosol volume increased for 6 months due to gas-to-particle conversion and then decreased to background levels in the following 6 months

    Langmuir Wave Generation Through A Neutrino Beam Instability

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    A standard version of a kinetic instability for the generation of Langmuir waves by a beam of electrons is adapted to describe the analogous instability due to a beam of neutrinos. The interaction between a Langmuir wave and a neutrino is treated in the one-loop approximation to lowest order in an expansion in 1/MW21/M_W^2 in the standard electroweak model. It is shown that this kinetic instability is far too weak to occur in a suggested application to the reheating of the plasma behind a stalled shock in a type II supernova (SN). This theory is also used to test the validity of a previous analysis of a reactive neutrino beam instability and various shortcomings of this theory are noted. In particular, it is noted that relativistic plasma effects have a significant effect on the calculated growth rates, and that any theoretical description of neutrino-plasma interactions must be based directly on the electroweak theory. The basic scalings discussed in this paper suggest that a more complete investigation of neutrino-plasma processes should be undertaken to look for an efficient process capable of driving the stalled shock of a type II SN.Comment: 23 pages, incl. 5 postscript figure

    An ecosystem characterisation of the Bay of Bengal

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    This study summarises the high level drivers on ecological systems of the BOBLME. The ecological characterisation resulted in the identification of 29 subsystems. The report recommends the development of fully integrated approaches that considers human needs and the ecological system, involving stakeholders in a transparent way
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