182 research outputs found

    Effects of replacing soybean meal with xylose-treated soybean meal on performance of nursing Awassi ewes and fattening lambs

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    Two experiments were conducted to evaluate the effect of replacing soybean meal with xylose-treated soybean meal (soypass meal; SPM) on performance of nursing Awassi ewes and fattening lambs. In Experiment 1, lasting for eight weeks, 39 Awassi ewes and their lambs were randomly assigned to three diets. Diets were formulated by replacing soybean meal from the basal diet (CON-SBM; n=13) with 50% (50% SPM; n=13) and 100% (100% SPM; n=13) SPM. Initial and final weights of the ewes were not different (P>0.55) among diets. Total gain and average daily gain (ADG) of lambs were similar (P=0.44) among diets. Ewes fed the CON-SBM diet tended (P<0.09) to have lower milk yields than those fed the 50% SPM and 100% SPM diets. No differences (P>0.38) in milk component percentages among diets were observed. In Experiment 2, lasting for 63 days, twenty weaned lambs were used to determine the effects of replacing soybean meal with SPM on growth performance. Diets were either soybean meal (SBM; n=10) or SPM (SPM; n=10). Nutrient intake and digestibility were not different between diets. However, rumen undegradable protein intake was greater (P<0.05) for the SPM diet than for the SBM diet. Final body weight, ADG and the feed conversion ratio were similar (P>0.05) between the diets. Results suggest that replacement of soybean meal with soypass meal is not likely to produce any production benefits in nursing Awassi ewes and fattening lambs except for the slight improvement of milk yield

    Observation of a Coherence Length Effect in Exclusive Rho^0 Electroproduction

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    Exclusive incoherent electroproduction of the rho^0(770) meson from 1H, 2H, 3He, and 14N targets has been studied by the HERMES experiment at squared four-momentum transfer Q**2>0.4 GeV**2 and positron energy loss nu from 9 to 20 GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the nuclear transparency, was found to decrease with increasing coherence length of quark-antiquark fluctuations of the virtual photon. The data provide clear evidence of the interaction of the quark- antiquark fluctuations with the nuclear medium.Comment: RevTeX, 5 pages, 3 figure

    Measurement of the Neutron Spin Structure Function g1ng_1^n with a Polarized ^3He Target

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    Results are reported from the HERMES experiment at HERA on a measurement of the neutron spin structure function g1n(x,Q2)g_1^n(x,Q^2) in deep inelastic scattering using 27.5 GeV longitudinally polarized positrons incident on a polarized 3^3He internal gas target. The data cover the kinematic range 0.023<x<0.60.023<x<0.6 and 1(GeV/c)2<Q2<15(GeV/c)21 (GeV/c)^2 < Q^2 <15 (GeV/c)^2. The integral 0.0230.6g1n(x)dx\int_{0.023}^{0.6} g_1^n(x) dx evaluated at a fixed Q2Q^2 of 2.5(GeV/c)22.5 (GeV/c)^2 is 0.034±0.013(stat.)±0.005(syst.)-0.034\pm 0.013(stat.)\pm 0.005(syst.). Assuming Regge behavior at low xx, the first moment Γ1n=01g1n(x)dx\Gamma_1^n=\int_0^1 g_1^n(x) dx is 0.037±0.013(stat.)±0.005(syst.)±0.006(extrapol.)-0.037\pm 0.013(stat.)\pm 0.005(syst.)\pm 0.006(extrapol.).Comment: 4 pages TEX, text available at http://www.krl.caltech.edu/preprints/OAP.htm

    Single Spin Asymmetry ANA_N in Polarized Proton-Proton Elastic Scattering at s=200\sqrt{s}=200 GeV

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    We report a high precision measurement of the transverse single spin asymmetry ANA_N at the center of mass energy s=200\sqrt{s}=200 GeV in elastic proton-proton scattering by the STAR experiment at RHIC. The ANA_N was measured in the four-momentum transfer squared tt range 0.003t0.0350.003 \leqslant |t| \leqslant 0.035 \GeVcSq, the region of a significant interference between the electromagnetic and hadronic scattering amplitudes. The measured values of ANA_N and its tt-dependence are consistent with a vanishing hadronic spin-flip amplitude, thus providing strong constraints on the ratio of the single spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated by the Pomeron amplitude at this s\sqrt{s}, we conclude that this measurement addresses the question about the presence of a hadronic spin flip due to the Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure

    Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV

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    We report a measurement of the longitudinal double-spin asymmetry A_LL and the differential cross section for inclusive Pi0 production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV. The cross section was measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be in good agreement with a next-to-leading order perturbative QCD calculation. The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T < 11 GeV/c and excludes a maximal positive gluon polarization in the proton. The mean transverse momentum fraction of Pi0's in their parent jets was found to be around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC

    High pTp_{T} non-photonic electron production in pp+pp collisions at s\sqrt{s} = 200 GeV

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    We present the measurement of non-photonic electron production at high transverse momentum (pT>p_T > 2.5 GeV/cc) in pp + pp collisions at s\sqrt{s} = 200 GeV using data recorded during 2005 and 2008 by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The measured cross-sections from the two runs are consistent with each other despite a large difference in photonic background levels due to different detector configurations. We compare the measured non-photonic electron cross-sections with previously published RHIC data and pQCD calculations. Using the relative contributions of B and D mesons to non-photonic electrons, we determine the integrated cross sections of electrons (e++e2\frac{e^++e^-}{2}) at 3 GeV/c<pT< c < p_T <~10 GeV/cc from bottom and charm meson decays to be dσ(Be)+(BDe)dyeye=0{d\sigma_{(B\to e)+(B\to D \to e)} \over dy_e}|_{y_e=0} = 4.0±0.5\pm0.5({\rm stat.})±1.1\pm1.1({\rm syst.}) nb and dσDedyeye=0{d\sigma_{D\to e} \over dy_e}|_{y_e=0} = 6.2±0.7\pm0.7({\rm stat.})±1.5\pm1.5({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure

    Evolution of the differential transverse momentum correlation function with centrality in Au+Au collisions at sNN=200\sqrt{s_{NN}} = 200 GeV

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    We present first measurements of the evolution of the differential transverse momentum correlation function, {\it C}, with collision centrality in Au+Au interactions at sNN=200\sqrt{s_{NN}} = 200 GeV. {\it C} exhibits a strong dependence on collision centrality that is qualitatively similar to that of number correlations previously reported. We use the observed longitudinal broadening of the near-side peak of {\it C} with increasing centrality to estimate the ratio of the shear viscosity to entropy density, η/s\eta/s, of the matter formed in central Au+Au interactions. We obtain an upper limit estimate of η/s\eta/s that suggests that the produced medium has a small viscosity per unit entropy.Comment: 7 pages, 4 figures, STAR paper published in Phys. Lett.

    Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV

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    We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage [-1.3, 1.3]. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes.Comment: 6 pages, 3 figure

    Measurement of the Bottom contribution to non-photonic electron production in p+pp+p collisions at s\sqrt{s} =200 GeV

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    The contribution of BB meson decays to non-photonic electrons, which are mainly produced by the semi-leptonic decays of heavy flavor mesons, in p+pp+p collisions at s=\sqrt{s} = 200 GeV has been measured using azimuthal correlations between non-photonic electrons and hadrons. The extracted BB decay contribution is approximately 50% at a transverse momentum of pT5p_{T} \geq 5 GeV/cc. These measurements constrain the nuclear modification factor for electrons from BB and DD meson decays. The result indicates that BB meson production in heavy ion collisions is also suppressed at high pTp_{T}.Comment: 6 pages, 4 figures, accepted by PR

    Cointegration analysis with state space models

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    Abstract: This paper presents and exemplifies results developed for cointegration analysis with state space models by Bauer and Wagner in a series of papers. Unit root processes, cointegration and polynomial cointegration are defined. Based upon these definitions the major part of the paper discusses how state space models, which are equivalent to VARMA models, can be fruitfully employed for cointegration analysis. By means of detailing the cases most relevant for empirical applications, the I(1), MFI(1) and I(2) cases, a canonical representation is developed and thereafter some available statistical results are briefly mentioned.
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