62,349 research outputs found

    One- and Two-Nucleon Structure form Green's Function Theory

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    We review some applications of self-consistent Green's function theory to studies of one- and two-nucleon structure in finite nuclei. Large-scale microscopic calculations that employ realistic nuclear forces are now possible. Effects of long-range correlations are seen to play a dominant role in determining the quenching of absolute spectroscopic factors. They also enhance considerably (e,e'pn) cross sections in superparallel kinematics, in agreement with observations.Comment: Proceedings of the International Symposium on "Forefronts of Researches in Exotic Nuclear Structures" (Niigata2010)

    Large boron--epoxy filament-wound pressure vessels

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    Advanced composite material used to fabricate pressure vessel is prepeg (partially cured) consisting of continuous, parallel boron filaments in epoxy resin matrix arranged to form tape. To fabricate chamber, tape is wound on form which must be removable after composite has been cured. Configuration of boron--epoxy composite pressure vessel was determined by computer program

    Charge Transport Transitions and Scaling in Disordered Arrays of Metallic Dots

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    We examine the charge transport through disordered arrays of metallic dots using numerical simulations. We find power law scaling in the current-voltage curves for arrays containing no voids, while for void-filled arrays charge bottlenecks form and a single scaling is absent, in agreement with recent experiments. In the void-free case we also show that the scaling exponent depends on the effective dimensionality of the system. For increasing applied drives we find a transition from 2D disordered filamentary flow near threshold to a 1D smectic flow which can be identified experimentally using characteristics in the transport curves and conduction noise.Comment: 4 pages, 4 postscript figure

    1/z-renormalization of the mean-field behavior of the dipole-coupled singlet-singlet system HoF_3

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    The two main characteristics of the holmium ions in HoF_3 are that their local electronic properties are dominated by two singlet states lying well below the remaining 4f-levels, and that the classical dipole-coupling is an order of magnitude larger than any other two-ion interactions between the Ho-moments. This combination makes the system particularly suitable for testing refinements of the mean-field theory. There are four Ho-ions per unit cell and the hyperfine coupled electronic and nuclear moments on the Ho-ions order in a ferrimagnetic structure at T_C=0.53 K. The corrections to the mean-field behavior of holmium triflouride, both in the paramagnetic and ferrimagnetic phase, have been calculated to first order in the high-density 1/z-expansion. The effective medium theory, which includes the effects of the single-site fluctuations, leads to a substantially improved description of the magnetic properties of HoF_3, in comparison with that based on the mean-field approximation.Comment: 26pp, plain-TeX, JJ

    Phonon-induced quadrupolar ordering of the magnetic superconductor TmNi2_2B2_2C

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    We present synchrotron x-ray diffraction studies revealing that the lattice of thulium borocarbide is distorted below T_Q = 13.5 K at zero field. T_Q increases and the amplitude of the displacements is drastically enhanced, by a factor of 10 at 60 kOe, when a magnetic field is applied along [100]. The distortion occurs at the same wave vector as the antiferromagnetic ordering induced by the a-axis field. A model is presented that accounts for the properties of the quadrupolar phase and explains the peculiar behavior of the antiferromagnetic ordering previously observed in this compound.Comment: submitted to PR

    Determining consumer expectations, attitudes and buying behaviour towards “low input” and organic foods

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    This paper reviews the first results and achievements of the QLIF SP1 “Determining consumer expectations and attitudes towards organic/low input food quality and safety”. The paper aims to illustrate the array of methodologies used and to discuss the ongoing research in light of the first results

    REVENUE IMPACTS OF MPP BRANDED FUNDS: A FIRM LEVEL ANALYSIS

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    The USDA recently redirected the Market Access Program (MAP) to allocate all branded products export promotion funds to small firms and cooperatives. The redirection was, in part, a response to reports by the General Accounting Office that were critical of past allocations of export promotion funds to large, experienced exporters. This study uses a firm level analysis to examine firms' effectiveness in using Market Promotion Program (MPP, which is now the MAP) funds to increase revenues. Whereas point estimates suggested that smaller firms were more effective in translating MPP funds into increased revenue than larger firms, these point estimates for small firms were statistically indistinguishable from zero. In contrast, large firms showed an increase in revenue of greater than one dollar for every dollar of MPP funds. Further, the revenue increase was statistically significant. Thus, the firm level analysis supports neither the GAO hypotheses nor the recent program changes.export promotion programs, export sales, export revenues, Market Promotion Program, firm-level analysis, joint estimation, Financial Economics,
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