30,724 research outputs found

    The Ohio Grain Marketing Legislation of 1982 and 1983

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    PDF pages: 6

    Ames collaborative study of cosmic-ray neutrons. 2: Low- and mid-latitude flights

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    Progress of the study of cosmic ray neutrons is described. Data obtained aboard flights from Hawaii at altitudes of 41,000 and 45,000 feet, and in the range of geomagnetic latitude 17 N less than or equal to lambda less than or equal to 21 N are reported. Preliminary estimates of neutron spectra are made

    Resolved, Every Librarian a Subject Librarian: Implementing Subject Librarianship Across a Research Library

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    Many academic research librarians are specialists—catalogers, data curation librarians, electronic resources librarians—and working with students is considered to be a job for public service librarians. The University of Tennessee Libraries is expanding subject librarian responsibility across the Libraries, and research librarians who may have never worked in public services are assuming liaison and collection development roles. Steve Smith, Dean of Libraries, will share his model of learning, research, and collections (LRC) librarianship and explain his rationale for starting the University of Tennessee, Knoxville Libraries down this road. And how is that concept working for us? Hear from a couple of the librarians charged with implementing the vision: a technical services librarian given new LRC subject responsibility and the public service librarian assigned to get that new LRC subject librarian up to speed. We will discuss organizational and implementation challenges and share what we have learned about training and mentoring new subject librarians

    Gamma-ray bursts and terrestrial planetary atmospheres

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    We describe results of modeling the effects on Earth-like planets of long-duration gamma-ray bursts (GRBs) within a few kiloparsecs. A primary effect is generation of nitrogen oxide compounds which deplete ozone. Ozone depletion leads to an increase in solar UVB radiation at the surface, enhancing DNA damage, particularly in marine microorganisms such as phytoplankton. In addition, we expect increased atmospheric opacity due to buildup of nitrogen dioxide produced by the burst and enhanced precipitation of nitric acid. We review here previous work on this subject and discuss recent developments, including further discussion of our estimates of the rates of impacting GRBs and the possible role of short-duration bursts.Comment: 12 pages including 5 figures (4 in color). Added discussion of GRB rates and biological effects. Accepted for publication in New Journal of Physics, for special issue "Focus on Gamma-Ray Bursts

    The Anthropometry of Forest Machine Operators in the Southern USA

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    Anthropometric dimensions critical to the design of operator workspaces and cab access in grapple skidders were collected from a sample of Southern United States loggers. The data were then compared to existing SAE and ILO anthropometric recommendations and data. Results indicated that southern grapple skidder operators are generally taller in stature, sitting height and seated eye height than the worldwide population measured to determine the SAE and ILO guides. Southern operators are also heavier than subjects measured for the SAE recommendations

    VLBA Continuum and H I Absorption Observations of the Ultra-Luminous Infrared Galaxy IRAS 17208-0014

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    We present phase-referenced VLBI observations of the radio continuum emission from, and the neutral hydrogen 21 cm absorption toward, the Ultra-Luminous Infrared Galaxy IRAS 17208-0014. The observations were carried out at 1362 MHz using the Very Long Baseline Array, including the phased Very Large Array as an element. The high-resolution radio continuum images reveal a nuclear starburst region in this galaxy, which is composed of diffuse emission approximately 670 x 340 pc on the plane of the sky, and a number of compact sources. These sources are most likely to be clustered supernova remnants and/or luminous radio supernovae. Their brightness temperatures range over (2.2-6.6) x 10^{5} K, with radio spectral luminosities between (1-10) x 10^{21} W Hz^{-1}. The total VLBI flux density of the starburst region is ~52 mJy, which is about 50% of the total flux density detected with the VLA at arcsecond resolution. For this galaxy, we derive a massive star formation rate of ~84pm13 M{_\odot} yr^{-1}, and a supernova rate of ~4pm1 yr^{-1}. H I absorption is detected in multiple components with optical depths ranging between 0.3 and 2.5, and velocity widths between 58 and 232 km s^{-1}. The derived column densities, assuming T_{s}=100 K, range over (10-26) x 10^{21} cm^{-2}. The H I absorption shows a strong velocity gradient of 453 km s^{-1} across 0.36 arcsec (274 pc). Assuming Keplerian motion, the enclosed dynamical mass is about 2.3 x 10^9 sin^{-2}i M{_\odot}, comparable to the enclosed dynamical mass estimated from CO observations.Comment: 26 pages total, 6 figures. ApJ accepted. To appear in the April 1, 2003 issue of ApJ. For a version with better images, see http://www.aoc.nrao.edu/~emomjian/IRAS.p

    Ames collaborative study of cosmic ray neutrons

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    The results of a collaborative study to define both the neutron flux and the spectrum more precisely and to develop a dosimetry package that can be flown quickly to altitude for solar flare events are described. Instrumentation and analysis techniques were used which were developed to measure accelerator-produced radiation. The instruments were flown in the Ames Research Center high altitude aircraft. Neutron instrumentation consisted of Bonner spheres with both active and passive detector elements, threshold detectors of both prompt-counter and activation-element types, a liquid scintillation spectrometer based on pulse-shape discrimination, and a moderated BF3 counter neutron monitor. In addition, charged particles were measured with a Reuter-Stokes ionization chamber system and dose equivalent with another instrument. Preliminary results from the first series of flights at 12.5 km (41,000 ft) are presented, including estimates of total neutron flux intensity and spectral shape and of the variation of intensity with altitude and geomagnetic latitude

    Ecology of the Invasive Red Alga Gracilaria salicornia (Rhodophyta) on O'ahu, Hawai'i

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    The red alga Gracilaria salicornia (C. Agardh) E. Y. Dawson was introduced intentionally to two reefs on O'ahu, Hawai'i, in the 1970s for experimental aquaculture for the agar industry. Some 30 yr later, this species has spread from the initial sites of introduction and is now competing with native marine flora and fauna. The goals of this study were to quantify various aspects of G. salicornia ecology in Hawai'i in an effort to develop control or eradication tools. Experimental plots were established to determine cover and biomass of G. salicornia per square meter and to determine the amount of time and person hours needed to remove G. salicornia from these plots. Substantial amounts of G. salicornia become dislodged from the reef during large wave events and periodically become deposited onto the beach in front of the Waikiki Aquarium. Algal beach wash biomass was quantified and positive relationships were established between swell height and the amount of algae that washed up onto the beach in this location. We then quantified the ability of G. salicornia vegetative fragments to regrow after desiccation to determine if algal biomass stranded on shore survives the tidal cycle until being washed back out on the reef at high tide. Gracilaria salicornia was remarkably resistant to temperature, salinity, and chemical treatments examined as possible in situ control options. Herbivore preference tests showed that a native Gracilaria species is consumed far more frequently than the alien congener. Finally, large-scale community volunteer efforts were organized to remove drifting G. salicornia fragments from the reef area in front of the Waikiki Aquarium. Over 20,000 kg of alien algal fragments were removed from this location in five 4-hr cleanup events. However, based on G. salicornia growth rates, ability to fragment, physical tolerance, and low herbivory, it is clear that a large-scale dedicated effort will be needed to control this invasive species on Waikiki's reefs
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