35,051 research outputs found

    A critical survey of upper-atmosphere density measurements by means of ionization gauges

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    Critical survey of upper atmosphere density measurements by ionization gauge

    A process yields large quantities of pure ribosome subunits

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    Development of process for in-vitro protein synthesis from living cells followed by dissociation of ribosomes into subunits is discussed. Process depends on dialysis or use of chelating agents. Operation of process and advantages over previous methods are outlined

    Behavior of the sonic boom shock wave near the sonic cutoff altitude

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    Behavior of sonic boom shock wave near sonic cutoff altitud

    The detection of markovian sequences of signals technical report no. 23

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    Detection of pure tone embedded in noise - Markov chains of signal

    Media Coverage of EPA\u27s Draft Dioxin Reassessment Report

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    Using content analysis, the authors examine the utility of news media in democratic decision making

    The Narrow-band Ultraviolet Imaging Experiment for Wide-field Surveys (NUVIEWS)-I: Dust scattered continuum

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    We report on the first results of the Narrow-band Ultraviolet Imaging Experiment for Wide-field Surveys (NUVIEWS), a sounding rocket experiment designed to map the far-ultraviolet background in four narrow bands. This is the first imaging measurement of the UV background to cover a substantial fraction of the sky. The narrow band responses (145, 155, 161, and 174 nm, 7-10 nm wide) allow us to isolate background contributions from dust-scattered continuum, H2 fluorescence, and CIV 155 nm emission. In our first flight, we mapped one quarter of the sky with 5-10 arcminute imaging resolution. In this paper, we model the dominant contribution of the background, dust-scattered continuum. Our data base consists of a map of over 10,000 sq. degrees with 468 independent measurements in 6.25 by 6.25 sq. degree bins. Stars and instrumental stellar halos are removed from the data. We present a map of the continuum background obtained in the 174 nm telescope. We use a model that follows Witt, Friedman, and Sasseen (1997: WFS) to account for the inhomogeneous radiation field and multiple scattering effects in clouds. We find that the dust in the diffuse interstellar medium displays a moderate albedo (a=0.55+/-0.1) and highly forward scattering phase function parameter (g=0.75+/-0.1) over a large fraction of the sky, similar to dust in star forming regions. We also have discovered a significant variance from the model.Comment: 16 pages, 3 ps figures, submitted to Astrophysical Journal Letter

    Experience in feeding coal into a liquefaction process development unit

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    A system for preparing coal slurry and feeding it into a high pressure liquefaction plant is described. The system was developed to provide supporting research and development for the Bureau of Mines coal liquefaction pilot plant. Operating experiences are included

    A review of congenital heart block

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    Congenital heart block is a rare disorder. It has an incidence of about 1 in 22,000 live births. It may be associated with high mortality and morbidity. This should generate a high index of suspicion for early diagnosis and aggressive therapy when appropriate. The congenital heart block associated with neonatal lupus is considered a form of passively acquired autoimmune disease in which maternal autoantibodies to the intracellular ribonucleoproteins Ro (SS-A) and La (SS-B), cross the placenta and injure the previously normal fetal heart. Women with serum titers of anti-Ro antibody carry a 3% risk of having a child with neonatal lupus syndrome. Recurrence rates are about 18%. We believe that serial echocardiograms should be acquired so that early diagnosis is made and aggressive therapy administered, if signs of conduction system disease such as PR interval prolongation by Doppler are found, so as to optimize the outcome. Establishment of guidelines for therapy have been set empirically, should signs of congenital heart block develop. Those patients whose congenital heart block is associated with structural heart disease have a higher morbidity and mortality, which is determined more by the underlying structural congenital heart disease than it is by the need for a pacemaker per se.peer-reviewe

    Extended Hodge Theory for Fibred Cusp Manifolds

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    For a particular class of pseudo manifolds, we show that the intersection cohomology groups for any perversity may be naturally represented by extended weighted L2L^2 harmonic forms for a complete metric on the regular stratum with respect to some weight determined by the perversity. Extended weighted L2L^2 harmonic forms are harmonic forms that are almost in the given weighted L2L^2 space for the metric in question, but not quite. This result is akin to the representation of absolute and relative cohomology groups for a manifold with boundary by extended harmonic forms on the associated manifold with cylindrical ends. As in that setting, in the unweighted L2L^2 case, the boundary values of the extended harmonic forms define a Lagrangian splitting of the boundary space in the long exact sequence relating upper and lower middle perversity intersection cohomology groups.Comment: 26 page

    Decay rate and other properties of the positronium negative ion

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    A new method for detecting the positronium minus ion is described, and the possibility of a long positronium mean free path in a solid is discussed
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