140,791 research outputs found

    Basic research in meteorology and atmospheric physics

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    The effect was studied of the variations of the electromagnetic properties of the three phases of water on measurements of atmospheric and oceanographic parameters by microwave instruments aboard satellites. Other studies reported include: orbital detection of extrasolar planets, detection of stratospheric aerosols from earth orbit, chemistry of Jupiter's atmosphere, and stratospheric ozone

    Band Symmetries and Singularities in Twisted Multilayer Graphene

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    The electronic spectra of rotationally faulted graphene bilayers are calculated using a continuum formulation for small fault angles that identifies two distinct electronic states of the coupled system. The low energy spectra of one state features a Fermi velocity reduction which ultimately leads to pairwise annihilation and regeneration of its low energy Dirac nodes. The physics in the complementary state is controlled by pseudospin selection rules that prevent a Fermi velocity renormalization and produce second generation symmetry-protected Dirac singularities in the spectrum. These results are compared with previous theoretical analyses and with experimental data.Comment: 5 pages, 3 figure

    Catalog of lunar mission data

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    Several series of spacecraft were developed, designed, built and launched to determine different characteristics of the lunar surface and environment for a manned landing. Both unmanned and manned spacecrafts, spacecraft equipment and lunar missions are documented

    SRC seal testing

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    Small venthole drilled in semisealed silicon-controlled rectifier (SCR) cavity eliminates entrapped helium. Although these devices show slightly greater leak than those before lead installation, it is now possible to distinguish device with good hermetic seal from defective one

    Long- term poverty and child development in the United States: Results from the NLSY

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    The authors describe developmental deficits in early childhood associated with long-term poverty in the National Longitudinal Survey of Youth (NLSY). They compare estimates of the effects of long-term poverty (based on a thirteen-year average of income) to estimates of the effects of poverty based on a single year of income (at the time of developmental assessment). They find substantial developmental deficits among children who, on average, are poor over a number of years relative to those who are not. These deficits are approximately twice as large according to the long-term income measure as compared to those based on the single- year measure, and are not explained by differences in maternal education, family structure, maternal behaviors during pregnancy, infant health, nutritional status, or age of mother at first birth. However, an index of the home environment accounts for one-third to one-half of the developmental disadvantages (net of other factors) of children who experience long-term poverty.
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