2,282 research outputs found

    Survey, analysis and evaluation test on high voltage/current pulse transmission cables

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    A survey, analysis, and testing of available cable connector configurations were carried out in connection with transmission of high voltage/current to an exploding wire bridge. Transmission was desired at high efficiency with maximum cable flexibility, at minimum weight and size of the cable connector, with maximum cable length while maintaining applicable voltage/current pulse characteristics, and with due consideration to environmental parameters

    Structure and Mechanism of a Metal-Sensing Regulatory RNA

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    SummaryOrganisms maintain the correct balance of intracellular metals primarily through metal-sensing proteins that control transport and storage of the target ion(s). Here, we reveal the basis of metal sensing and genetic control by a metalloregulatory RNA. Our data demonstrate that a previously uncharacterized orphan riboswitch, renamed the “M-box,” is a divalent metal-sensing RNA involved in Mg2+ homeostasis. A combination of genetic, biochemical, and biophysical techniques demonstrate that Mg2+ induces a compacted tertiary architecture for M-box RNAs that regulates the accessibility of nucleotides involved in genetic control. Molecular details are provided by crystallographic structure determination of a Mg2+-bound M-box RNA. Given the distribution of this RNA element, it may constitute a common mode for bacterial metal ion regulation, and its discovery suggests the possibility of additional RNA-based metal sensors in modern and primordial organisms

    Gravitational Microlensing Evidence for a Planet Orbiting a Binary Star System

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    The study of extra-solar planetary systems has emerged as a new discipline of observational astronomy in the past few years with the discovery of a number of extra-solar planets. The properties of most of these extra-solar planets were not anticipated by theoretical work on the formation of planetary systems. Here we report observations and light curve modeling of gravitational microlensing event MACHO-97-BLG-41, which indicates that the lens system consists of a planet orbiting a binary star system. According to this model, the mass ratio of the binary star system is 3.8:1 and the stars are most likely to be a late K dwarf and an M dwarf with a separation of about 1.8 AU. A planet of about 3 Jupiter masses orbits this system at a distance of about 7 AU. If our interpretation of this light curve is correct, it represents the first discovery of a planet orbiting a binary star system and the first detection of a Jovian planet via the gravitational microlensing technique. It suggests that giant planets may be common in short period binary star systems.Comment: 11 pages, with 1 color and 2 b/w Figures included (published version

    It’s the Combination: Scientific Data Review of the First Corn Silage to Bring Together Fiber and Starch Digestibility

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    This information was presented at the 2017 Cornell Nutrition Conference for Feed Manufacturers, organized by the Department of Animal Science In the College of Agriculture and Life Sciences at Cornell University. Softcover copies of the entire conference proceedings may be purchased at http://ansci.cals.cornell.edu/extension-outreach/adult-extension/dairy-management/order-proceedings-resources.A recent study compared a newly developed brown midrib 3 corn silage with floury endosperm to a conventional corn silage and a brown midrib 3 corn silage for high-producing Holstein cows. The combination of greater rumen fiber and starch fermentability of the new hybrid resulted in greater efficiency of solids-corrected milk production and milk nitrogen efficiency compared with the brown midrib and conventional hybrids

    Tourism policy and destination marketing in developing countries: the chain of influence

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    Tourism marketers including destination marketing organisations (DMOs) and international tour operators play a pivotal role in destination marketing, especially in creating destination images. These images, apparent in tourist brochures, are designed to influence tourist decision-making and behaviour. This paper proposes the concept of a “chain of influence” in destination marketing and image-making, suggesting that the content of marketing materials is influenced by the priorities of those who design these materials, e.g. tour operators and DMOs. A content analysis of 2,000 pictures from DMO and tour operator brochures revealed synergies and divergence between these marketers. The brochure content was then compared to the South African tourism policy, concluding that the dominant factor in the chain of influence in the South African context is in fact its organic image

    Cymantrene–Triazole "Click" Products: Structural Characterization and Electrochemical Properties

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    We report the first known examples of triazole-derivatized cymantrene complexes (η5-[4-substituted triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I), obtained via a “click” chemical synthesis, bearing a phenyl, 3-aminophenyl, or 4-aminophenyl moiety at the 4-position of the triazole ring. Structural characterization data using multinuclear NMR, UV–vis, ATR-IR, and mass spectrometric methods are provided, as well as crystallographic data for (η5-[4-phenyltriazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I) and (η5-[4-(3-aminophenyl)triazol-1-yl]cyclopentadienyl)tricarbonylmanganese(I). Cyclic voltammetric characterization of the redox behavior of each of the three cymantrene–triazole complexes is presented together with digital simulations, in situ infrared spectroelectrochemistry, and DFT calculations to extract the associated kinetic and thermodynamic parameters. The trypanocidal activity of each cymantrene–triazole complex is also examined, and these complexes are found to be more active than cymantrene alone

    Magnetic phase diagram of cubic perovskites SrMn_1-xFe_xO_3

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    We combine the results of magnetic and transport measurements with Mossbauer spectroscopy and room-temperature diffraction data to construct the magnetic phase diagram of the new family of cubic perovskite manganites SrMn_1-xFe_xO_3. We have found antiferromagnetic ordering for lightly and heavily Fe-substituted material, while intermediate substitution leads to spin-glass behavior. Near the SrMn_0.5Fe_0.5O_3 composition these two types of ordering are found to coexist and affect one another. The spin glass behavior may be caused by competing ferro- and antiferromagnetic interactions among Mn^4+ and observed Fe^3+ and Fe^5+ ions.Comment: 8 pages, 10 figures, revtex, accepted to Phys. Rev.
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