3,057 research outputs found

    Interstellar H^+_3: possible detection of the 1_(10)→1_(11) transition of H_2D^+

    Get PDF
    An interstellar line has been detected in emission at the expected submillimeter wavelength of the 1_(10)→1_(11) transition of H_(2)D^+, the deuterated version of the primary ion (H^(+)_(3)) in the favored ion-molecule reaction scheme for interstellar gas phase chemistry. The strength of the line is in approximate agreement with the theoretically anticipated H_(2)D^+ abundance

    Reviews

    Full text link

    Far infrared maps of the ridge between OMC-1 and OMC-2

    Get PDF
    Dust continuum emission from a 6 ft x 20 ft region surrounding OMC-1 and OMC-2 were mapped at 55 and 125 microns with 4 ft resolution. The dominant features of the maps are a strong peak at OMC-1 and a ridge of lower surface brightness between OMC-1 and OMC-2. Along the ridge the infrared flux densities and the color temperature decreases smoothly from OMC-1 to OMC-2. OMC-1 is heated primarily by several optical and infrared stars situated within or just at the boundary of the cloud. At the region of minimum column density between OMC-1 and OMC-2 the nearby B0.5 V star NU Ori may contribute significantly to the dust heating. Near OMC-2 dust column densities are large enough so that, in addition to the OMC-2 infrared cluster, the nonlocal infrared sources associated with OMC-1 and NU Ori can contribute to the heating

    Far infrared and submillimeter brightness temperatures of the giant planets

    Get PDF
    The brightness temperatures of Jupiter, Saturn, Uranus, and Neptune in the range 35 to 1000 micron. The effective temperatures derived from the measurements, supplemented by shorter wavelength Voyager data for Jupiter and Saturn, are 126.8 + or - 4.5 K, 93.4 + or - 3.3 K, 58.3 + or - 2.0 K, and 60.3 + or - 2.0 K, respectively. The implications of the measurements for bolometric output and for atmospheric structure and composition are discussed. The temperature spectrum of Jupiter shows a strong peak at approx. 350 microns followed by a deep valley at approx. 450 to 500 microns. Spectra derived from model atmospheres qualitatively reproduced these features but do not fit the data closely

    The global dynamics of RNA stability orchestrates responses to cellular activation

    Get PDF
    Transcriptomics is used to quantify changes in accumulated levels of mRNAs following cellular activation. These changes arise from the opposing fluxes of transcription and mRNA decay, both of which affect the functional dynamics of global gene expression. A study published recently in BMC Genomics focuses on the contribution made by mRNA stability in shaping the kinetics of gene responses in mammalian cells

    Submarine landslides on the upper southeast Australian passive continental margin – preliminary findings

    Get PDF
    The southeast Australian passive continental margin is narrow, steep and sediment-deficient, and characterized by relatively low rates of modern sedimentation. Upper slope (\u3c1200m) sediments comprise mixtures of calcareous and terrigenous sand and mud. Three of twelve sediment cores recovered from geologically-recent, submarine landslides located offshore New South Wales/Queensland (NSW/QLD) are interpreted to have sampled failure surfaces at depths of between 85 cm and 220 cm below the present-day seabed. Differences in sediment physical properties are recorded above and below the three slide-plane boundaries. Sediment taken directly above the inferred submarine landslide failure surfaces and presumed to be post-landslide, returned radiocarbon ages of 15.8 ka, 20.7 ka and 20.1 ka. The last two ages correspond to adjacent slide features, which are inferred to be consistent with their being triggered by a single event such as an earthquake. Slope stability models based on classical soil mechanics and measured sediment shearstrengths indicate that the upper slope sediments should be stable. However, multibeam sonar data reveal that many upper slope landslides occur across the margin and that submarine landsliding is a common process. We infer from these results that: a) an unidentified mechanism regularly acts to reduce the shear resistance of these sediments to the very low values required to enable slope failure, and/or b) the margin experiences seismic events that act to destabilise the slope sediments

    Focused laser Doppler velocimeter

    Get PDF
    A system for remotely measuring velocities present in discrete volumes of air is described. A CO2 laser beam is focused by a telescope at such a volume, a focal volume, and within the focusable range, near field, of the telescope. The back scatter, or reflected light, principally from the focal volume, passes back through the telescope and is frequency compared with the original frequency of the laser, and the difference frequency or frequencies represent particle velocities in that focal volume

    Regional representation versus hit-making: Canadian music policy at the crossroads.

    Get PDF
    This thesis is a study of Canadian government regulations and programs that support the country\u27s domestic music industry. Specifically, this study questions if the focus of these policies favours production of hit-makers whose music is geared to appeal on an international level, as opposed to musicians who convey a Canadian identity (with possible spillover appeal in the global music market.) The cultural industries approach, as outlined by Sinclair (1997), offers a salient theoretical perspective for this study. This approach acknowledges that popular music is produced, distributed and marketed in a process wherein consumer demand is manufactured and managed. It also recognizes, however, that popular culture is manifest through a dialectic between pervasive consumer culture and localized social experience. Laba (1988) frames these ideas into a Canadian context, and in the process he positions the popular culture dialectic in the context of Canada\u27s music industry. This dialectic reflects the struggle between Canadian independent labels (which produce local and regional sounds) and major transnational music companies (which appropriate local sounds for their international consumer base). This study uses the cultural industries approach to: (1) observe how government policies have promoted Canadian music into the late 1990s, taking into account their historical development and the various agents involved, and (2) investigate the structure of the Canadian music industry, observing its various agents and the economics of music production, distribution and promotion. A final chapter reviews the findings and proposes ways in which the popular culture of regionalism can be better promoted through Canadian music policies.Dept. of Communication Studies. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1997 .K43. Source: Masters Abstracts International, Volume: 37-01, page: 0012. Adviser: Myles Ruggles. Thesis (M.A.)--University of Windsor (Canada), 1997
    • …
    corecore