1,813 research outputs found

    Sidewinder: Creative Missile Development at China Lake

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    The environment of x ray selected BL Lacs: Host galaxies and galaxy clustering

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    Using the Canada-France-Hawaii Telescope, we have imaged a complete, flux-limited sample of Einstein Medium Sensitivity Survey BL Lacertae objects in order to study the properties of BL Lac host galaxies and to use quantitative methods to determine the richness of their galaxy cluster environments

    Intermountain Planting Guide

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    The first consideration prior to seeding is to determine the present level of management being applied to the proposed site. Many sites will recover or improve without seeding if proper management is implemented. Soil is the primary natural resource and its conservation is the most important consideration in seedings

    A 1.1 to 1.9 GHz SETI Survey of the Kepler Field: I. A Search for Narrow-band Emission from Select Targets

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    We present a targeted search for narrow-band (< 5 Hz) drifting sinusoidal radio emission from 86 stars in the Kepler field hosting confirmed or candidate exoplanets. Radio emission less than 5 Hz in spectral extent is currently known to only arise from artificial sources. The stars searched were chosen based on the properties of their putative exoplanets, including stars hosting candidates with 380 K > T_eq > 230 K, stars with 5 or more detected candidates or stars with a super-Earth (R_p 50 day orbit. Baseband voltage data across the entire band between 1.1 and 1.9 GHz were recorded at the Robert C. Byrd Green Bank Telescope between Feb--Apr 2011 and subsequently searched offline. No signals of extraterrestrial origin were found. We estimate that fewer than ~1% of transiting exoplanet systems host technological civilizations that are radio loud in narrow-band emission between 1-2 GHz at an equivalent isotropically radiated power (EIRP) of ~1.5 x 10^21 erg s^-1, approximately eight times the peak EIRP of the Arecibo Planetary Radar, and we limit the the number of 1-2 GHz narrow-band-radio-loud Kardashev type II civilizations in the Milky Way to be < 10^-6 M_solar^-1. Here we describe our observations, data reduction procedures and results.Comment: Accepted to the Astrophysical Journa

    High-precision determination of the light-quark masses from realistic lattice QCD

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    Three-flavor lattice QCD simulations and two-loop perturbation theory are used to make the most precise determination to date of the strange-, up-, and down-quark masses, msm_s, mum_u, and mdm_d, respectively. Perturbative matching is required in order to connect the lattice-regularized bare- quark masses to the masses as defined in the \msbar scheme, and this is done here for the first time at next-to-next-to leading (or two-loop) order. The bare-quark masses required as input come from simulations by the MILC collaboration of a highly-efficient formalism (using so-called ``staggered'' quarks), with three flavors of light quarks in the Dirac sea; these simulations were previously analyzed in a joint study by the HPQCD and MILC collaborations, using degenerate uu and dd quarks, with masses as low as ms/8m_s/8, and two values of the lattice spacing, with chiral extrapolation/interpolation to the physical masses. With the new perturbation theory presented here, the resulting \msbar\ masses are m^\msbar_s(2 {GeV}) = 87(0)(4)(4)(0) MeV, and \hat m^\msbar(2 {GeV}) = 3.2(0)(2)(2)(0) MeV, where \hat m = \sfrac12 (m_u + m_d) is the average of the uu and dd masses. The respective uncertainties are from statistics, simulation systematics, perturbation theory, and electromagnetic/isospin effects. The perturbative errors are about a factor of two smaller than in an earlier study using only one-loop perturbation theory. Using a recent determination of the ratio mu/md=0.43(0)(1)(0)(8)m_u/m_d = 0.43(0)(1)(0)(8) due to the MILC collaboration, these results also imply m^\msbar_u(2 {GeV}) = 1.9(0)(1)(1)(2) MeV and m^\msbar_d(2 {GeV}) = 4.4(0)(2)(2)(2) MeV. A technique for estimating the next order in the perturbative expansion is also presented, which uses input from simulations at more than one lattice spacing

    Weed control in soybeans

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    The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

    Accounting regulation in the UK: one nation, two sectors

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    This paper draws on the work of Streeck and Schmitter (1985) and its subsequent use by Puxty, et al (1987) to analyse the development of accounting regulation in the U.K. public sector. It provides an extension to prior literature through the application of a framework, based on modes of social order, to investigate divergence in the approaches to accounting regulation between the public and private sectors within a single nation state. Despite the advent of ‘New Public Management’, a different balance of the principles of regulation was established and continues to exist in the public sector when compared with that applied in the private sector, reflected by their respective approaches to due process. The conclusion is that the UK public sector accounting regulatory structure remains rooted in the state mode of social order and hence is different from that found in the private sector, despite the rhetoric of modernisation through the adoption of private sector management practices
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