7,646 research outputs found

    THE CONSEQUENCES OF AN OPEN FIELD BURNING BAN ON THE U.S. KENTUCKY BLUEGRASS SEED INDUSTRY

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    An econometric model of the U.S. Kentucky bluegrass seed industry in the Pacific Northwest is specified and estimated in order to evaluate the short and long run consequences of yield reductions associated with a ban on open field burning of grass residues. While results differ among regions, model simulations of short run effects of reduced yields attributed to the burning ban indicate price increases for grass seed ranging from 0 to 69 percent and long run effects indicate increased acreage of grass seed production due to producers responses to higher prices.Crop Production/Industries,

    Assessing the Effectiveness of Farm Supply Cooperatives: A Comparison of Farmer and Manager Viewpoints

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    This paper reports the results of a survey of attitudes of commercial farmers and supply cooperative managers about agricultural supply cooperatives. Cooperative managers and farmers frequently made significantly different responses to questionnaire statements. With a few expectations, farm size and farmer age did not appear to influence perceptions about supply cooperatives. Whether a farmer was a cooperative member was important in some cases. Lower prices in lieu of easy credit and patronage refunds were found to be acceptable to farmers, but not at the expense of good service. Managers placed great importance on member loyalty to the supply cooperative without regard to price consideration.Agribusiness,

    On the Nature of the Strong Emission-Line Galaxies in Cluster Cl 0024+1654: Are Some the Progenitors of Low Mass Spheroidals?

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    We present new size, line ratio, and velocity width measurements for six strong emission-line galaxies in the galaxy cluster, Cl 0024+1654, at redshift z~0.4. The velocity widths from Keck spectra are all narrow (30<sigma<120 km/s), with three profiles showing double peaks. Four galaxies have low masses (M<10^{10} Mo). Whereas three galaxies were previously reported to be possible AGNs, none exhibit AGN-like emission line ratios or velocity widths. Two or three appear as very blue spirals with the remainder more akin to luminous H-II galaxies undergoing a strong burst of star formation. We propose that after the burst subsides, these galaxies will transform into quiescent dwarfs, and are thus progenitors of some cluster spheroidals (We adopt the nomenclature suggested by Kormendy & Bender (1994), i.e., low-density, dwarf ellipsoidal galaxies like NGC 205 are called `spheroidals' instead of `dwarf ellipticals') seen today.Comment: 14 pages + 2 figures + 1 table, LaTeX, Acc. for publ. in ApJL also available at http://www.ucolick.org/~deep/papers/papers.htm

    A dislocation dynamics study of the strength of stacking fault tetrahedra. Part II: interactions with mixed and edge dislocations

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    In this paper we present the sequel to Part I and present a comprehensive dislocation dynamics study of the strength of stacking fault tetrahedra to mixed and edge dislocation glides in fcc Cu

    Comment on "Zeeman-Driven Lifshitz Transition: A Model for the Experimentally Observed Fermi-Surface Reconstruction in YbRh2Si2"

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    In Phys. Rev. Lett. 106, 137002 (2011), A. Hackl and M. Vojta have proposed to explain the quantum critical behavior of YbRh2Si2 in terms of a Zeeman-induced Lifshitz transition of an electronic band whose width is about 6 orders of magnitude smaller than that of conventional metals. Here, we note that the ultra-narrowness of the proposed band, as well as the proposed scenario per se, lead to properties which are qualitatively inconsistent with the salient features observed in YbRh2Si2 near its quantum critical point.Comment: 3 page

    Evidence for a Kondo destroying quantum critical point in YbRh2Si2

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    The heavy-fermion metal YbRh2_{2}Si2_{2} is a weak antiferromagnet below TN=0.07T_{N} = 0.07 K. Application of a low magnetic field Bc=0.06B_{c} = 0.06 T (c\perp c) is sufficient to continuously suppress the antiferromagnetic (AF) order. Below T10T \approx 10 K, the Sommerfeld coefficient of the electronic specific heat γ(T)\gamma(T) exhibits a logarithmic divergence. At T<0.3T < 0.3 K, γ(T)Tϵ\gamma(T) \sim T^{-\epsilon} (ϵ:0.30.4\epsilon: 0.3 - 0.4), while the electrical resistivity ρ(T)=ρ0+aT\rho(T) = \rho_{0} + aT (ρ0\rho_{0}: residual resistivity). Upon extrapolating finite-TT data of transport and thermodynamic quantities to T=0T = 0, one observes (i) a vanishing of the "Fermi surface crossover" scale T(B)T^{*}(B), (ii) an abrupt jump of the initial Hall coefficient RH(B)R_{H}(B) and (iii) a violation of the Wiedemann Franz law at B=BcB = B_{c}, the field-induced quantum critical point (QCP). These observations are interpreted as evidence of a critical destruction of the heavy quasiparticles, i.e., propagating Kondo singlets, at the QCP of this material.Comment: 20 pages, 8 figures, SCES 201
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