68,507 research outputs found

    Angular Power Spectra of the COBE DIRBE Maps

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    The angular power spectra of the infrared maps obtained by the DIRBE (Diffuse InfraRed Background Experiment) instrument on the COBE satellite have been obtained by two methods: the Hauser-Peebles method previously applied to the DMR maps, and by Fourier transforming portions of the all-sky maps projected onto a plane. The two methods give consistent results, and the power spectrum of the high-latitude dust emission is C_\ell \propto \ell^{-3} in the range 2 < \ell < 300.Comment: ApJ in press. 15 pages with 5 included figure

    Cost and size estimates for an electrochemical bulk energy storage concept

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    Preliminary capital cost and size estimates were made for an electrochemical bulk energy storage concept. The electrochemical system considered was an electrically rechargeable flow cell with a redox couple. On the basis of preliminary capital cost estimates, size estimates, and several other important considerations, the redox-flow-cell system emerges as having great promise as a bulk energy storage system for power load leveling. The size of this system would be less than 2 percent of that of a comparable pumped hydroelectric plant. The capital cost of a 10-megawatt, 60- and 85-megawatt-hour redox system is estimated to be 190to190 to 330 per kilowatt. The other important features of the redox system contributing to its load leveling application are its low adverse environmental impact, its high efficiency, its apparent absence of electrochemically-related cycle life limitations, and its fast response

    Child undernutrition in affluent societies: what are we talking about?

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    In this paper we set out to explore the prevalence of child undernutrition found in community studies in affluent societies, but a preliminary literature review revealed that, in the absence of a gold standard method of diagnosis, the prevalence largely depends on the measure, threshold and the growth reference used, as well as age. We thus go on to explore describe the common clinical ‘syndromes’ of child undernutrition: wasting, stunting and failure to thrive (weight faltering) and how we have used data from two population-based cohort studies, this paper to explore how much these different ‘syndromes’ overlap and the extent to which they reflect true undernutrition. This analysis revealed that when more than one definition is applied to the same children, a majority are below the lower threshold for only one measure. However, those with both weight faltering and low BMI in infancy, go on in later childhood to show growth and body composition patterns suggestive of previous undernutrition. In older children there is even less overlap and most children with either wasting or low fat seem to be simply growing at one extreme of the normal range. We conclude that in affluent societies the diagnosis of undernutrition is only robust when it relies on a combination of both, that is decline in weight or BMI centile and wasting

    High resolution CO images of Seyfert Galaxies

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    The CO (J = 1-0) emission of three Seyfert galaxies, NGC 3227, NGC 7469, and NGC 5033 was imaged. The CO emission in NGC 3227 and NGC 7469 appears as compact structures centered on the active nuclei, containing substantial fractions of the single-dish flux. In NGC 3227, 10 percent of the CO flux detected by the interferometer is contained within the ionized narrow-line region. The unresolved molecular gas concentrations in the nucleus of NGC 3227 imply a CO mass of 65 million solar masses concentrated within a diameter less than 50 pc. The CO emission in NGC 5033 is not detected at this resolution, implying a CO structure size of 20 to 60 arcsec. Continuum emission at 2.7 mm is not detected in any of the three galaxies. In the center of NGC 7469, the H2 mass is comparable to the dynamical mass. Kinematic studies of the detected gas reveal a rotational motion of the gas in NGC 3227 and NGC 7469, allowing identification of the gas in NGC 7469 with a nuclear starburst. These data are consistent with the idea that interactions between galaxies cause gas to concentrate in their nuclei thereby feeding starburst and Seyfert activity

    Use tax collections

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    The article reports on a study which investigated the level of compliance with U.S. state use tax laws and the techniques employed by the states in order to enforce use tax. Most states utilize either of two forms of tax reporting and collection. These are: the introduction of a separate use tax form/return; or the use of a separate line on the state income tax return. It was observed that utilizing a separate line item on the state income tax return might cause a rise in the number of taxpayers

    Angular Power Spectrum of the Microwave Background Anisotropy seen by the COBE Differential Microwave Radiometer

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    The angular power spectrum estimator developed by Peebles (1973) and Hauser & Peebles (1973) has been modified and applied to the 2 year maps produced by the COBE DMR. The power spectrum of the real sky has been compared to the power spectra of a large number of simulated random skies produced with noise equal to the observed noise and primordial density fluctuation power spectra of power law form, with P(k)knP(k) \propto k^n. Within the limited range of spatial scales covered by the COBE DMR, corresponding to spherical harmonic indices 3 \leq \ell \lsim 30, the best fitting value of the spectral index is n=1.250.45+0.4n = 1.25^{+0.4}_{-0.45} with the Harrison-Zeldovich value n=1n = 1 approximately 0.5σ\sigma below the best fit. For 3 \leq \ell \lsim 19, the best fit is n=1.460.44+0.39n = 1.46^{+0.39}_{-0.44}. Comparing the COBE DMR ΔT/T\Delta T/T at small \ell to the ΔT/T\Delta T/T at 50\ell \approx 50 from degree scale anisotropy experiments gives a smaller range of acceptable spectral indices which includes n=1n = 1.Comment: 22 pages of LaTex using aaspp.sty and epsf.sty with appended Postscript figures, COBE Preprint 94-0
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