3,766 research outputs found

    GRID PRICING FOR FED CATTLE: AN EMPIRICAL ANALYSIS

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    Weekly grid premium and discount price date for fed cattle have been collected over a 3-year period. The grid price data are combined with carcass data (2590 South Dakota slaughter steers) to investigate the variability in the average weekly carcass premium is affected by changes in packer-determined grid premiums and discounts on a weekly basis. The three-stage recursive model is then estimated using an autoregressive procedure. The results of the empirical analysis indicated that among all grid premiums and discounts, it is the choice-select discount that plays the dominant role in determining weekly changes in the average weekly carcass premium (discount).slaughter cattle, grid pricing, average pricing, value-based-marketing, Marketing,

    Numerical simulation of heavy fermions in an SU(2)_L x SU(2)_R symmetric Yukawa model

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    An exploratory numerical study of the influence of heavy fermion doublets on the mass of the Higgs boson is performed in the decoupling limit of a chiral SU(2)LSU(2)R\rm SU(2)_L \otimes SU(2)_R symmetric Yukawa model with mirror fermions. The behaviour of fermion and boson masses is investigated at infinite bare quartic coupling on 4384^3 \cdot 8, 63126^3 \cdot 12 and 83168^3 \cdot 16 lattices. A first estimate of the upper bound on the renormalized quartic coupling as a function of the renormalized Yukawa-coupling is given.Comment: 15 pp + 11 Figures appended as Postscript file

    Single aggressive interactions increase urinary glucocorticoid levels in wild male chimpanzees

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    Financial support was provided by British Academy [http://www.britac.ac.uk/] (CC), Leakey Foundation [http://www.leakeyfoundation.org/] (CC, RMW, TD), Leverhulm Trust [http://www.leverhulme.ac.uk/] (KZ), Max Planck Society [http://www.eva.mpg.de/] (AW, CC, RMW, TD) and the Royal Zoological Society of Scotland [http://www.rzss.org.uk/], in providing core funding for Budongo Conservation Field Station. This project has received additional funding from the European Union’s Seventh Framework Program for research, technological development and demonstration [http://ec.europa.eu/research/fp7/index_e​n.cfm] under grant agreement no 283871.A basic premise in behavioural ecology is the cost-benefit arithmetic, which determines both behavioural decisions and evolutionary processes. Aggressive interactions can be costly on an energetic level, demanding increased energy or causing injuries, and on a psychological level, in the form of increased anxiety and damaged relationships between opponents. Here we used urinary glucocorticoid (uGC) levels to assess the costs of aggression in wild chimpanzees of Budongo Forest, Uganda. We collected 169 urine samples from nine adult male chimpanzees following 14 aggressive interactions (test condition) and 10 resting events (control condition). Subjects showed significantly higher uGC levels after single aggressive interactions compared to control conditions, likely for aggressors as well as victims. Higher ranking males had greater increases of uGC levels after aggression than lower ranking males. In contrast, uGC levels showed no significant change in relation to aggression length or intensity, indicating that psychological factors might have played a larger role than mere energetic expenditure. We concluded that aggressive behaviour is costly for both aggressors and victims and that costs seem poorly explained by energetic demands of the interaction. Our findings are relevant for studies of post-conflict interactions, since we provide evidence that both aggressors and victims experience a stress response to conflict.Publisher PDFPeer reviewe

    Characterization of new hybrid pixel module concepts for the ATLAS Insertable B-Layer upgrade

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    The ATLAS Insertable B-Layer (IBL) collaboration plans to insert a fourth pixel layer inside the present Pixel Detector to recover from eventual failures in the current pixel system, especially the b-layer. Additionally the IBL will ensure excellent tracking, vertexing and b-tagging performance during the LHC phase I and add robustness in tracking with high luminosity pile-up. The expected peak luminosity for IBL is 2 to 3centerdot1034 cm-2s-1 and IBL is designed for an integrated luminosity of 700 fb-1. This corresponds to an expected fluence of 5centerdot1015 1 MeV neqcm-2 and a total ionizing dose of 250 MRad. In order to cope with these requirements, two new module concepts are under investigation, both based on a new front end IC, called FE-I4. This IC was designed as readout chip for future ATLAS Pixel Detectors and its first application will be the IBL. The planar pixel sensor (PPS) based module concept benefits from its well understood design, which is kept as similar as possible to the design of the current ATLAS Pixel Detector sensor. The second approach of the new three dimensional (3D) silicon sensor technology benefits from the shorter charge carrier drift distance to the electrodes, which completely penetrate the sensor bulk. Prototype modules of both sensor concepts have been build and tested in laboratory and test beam environment before and after irradiation. Both concepts show very high performance even after irradiation to 5centerdot1015 1 MeV neqcm-2 and meet the IBL specifications in terms of hit efficiency being larger than 97%. Lowest operational threshold studies have been effected and prove independent of the used sensor concept the excellent performance of FE-I4 based module concepts in terms of noise hit occupancy at low thresholds.Comment: Part of 9th International Conference on Position Sensitive Detectors (PSD9

    Nucleon axial form factors from two-flavour Lattice QCD

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    We present preliminary results on the axial form factor GA(Q2)G_A(Q^2) and the induced pseudoscalar form factor GP(Q2)G_P(Q^2) of the nucleon. A systematic analysis of the excited-state contributions to form factors is performed on the CLS ensemble `N6' with mπ=340 MeVm_\pi = 340 \ \text{MeV} and lattice spacing a0.05 fma \sim 0.05 \ \text{fm}. The relevant three-point functions were computed with source-sink separations ranging from ts0.6 fmt_s \sim 0.6 \ \text{fm} to $t_s \sim \ 1.4 \ \text{fm}$. We observe that the form factors suffer from non-trivial excited-state contributions at the source-sink separations available to us. It is noted that naive plateau fits underestimate the excited-state contributions and that the method of summed operator insertions correctly accounts for these effects.Comment: 7 pages, 12 figures; talk presented at Lattice 2014 -- 32nd International Symposium on Lattice Field Theory, 23-28 June, 2014, Columbia University New York, N

    Benchmarking computer platforms for lattice QCD applications

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    We define a benchmark suite for lattice QCD and report on benchmark results from several computer platforms. The platforms considered are apeNEXT, CRAY T3E, Hitachi SR8000, IBM p690, PC-Clusters, and QCDOC.Comment: 3 pages, Lattice03, machines and algorithm

    Nucleon electromagnetic form factors in two-flavour QCD

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    We present results for the nucleon electromagnetic form factors, including the momentum transfer dependence and derived quantities (charge radii and magnetic moment). The analysis is performed using O(a) improved Wilson fermions in Nf=2 QCD measured on the CLS ensembles. Particular focus is placed on a systematic evaluation of the influence of excited states in three-point correlation functions, which lead to a biased evaluation, if not accounted for correctly. We argue that the use of summed operator insertions and fit ans\"atze including excited states allow us to suppress and control this effect. We employ a novel method to perform joint chiral and continuum extrapolations, by fitting the form factors directly to the expressions of covariant baryonic chiral effective field theory. The final results for the charge radii and magnetic moment from our lattice calculations include, for the first time, a full error budget. We find that our estimates are compatible with experimental results within their overall uncertainties.Comment: 22 pages, 10 figures, citations modifie

    An ``Improved" Lattice Study of Semi-leptonic Decays of D-Mesons

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    We present results of a lattice computation of the matrix elements of the vector and axial-vector currents which are relevant for the semi-leptonic decays DKD \rightarrow K and DKD \rightarrow K^*. The computations are performed in the quenched approximation to lattice QCD on a 243×4824^3 \times 48 lattice at β=6.2\beta=6.2, using an O(a)O(a)-improved fermionic action. In the limit of zero lepton masses the semi-leptonic decays DKD \rightarrow K and DKD \rightarrow K^* are described by four form factors: fK+,V,A1f^{+}_K,V,A_1 and A2A_2, which are functions of q2q^2, where qμq^{\mu} is the four-momentum transferred in the process. Our results for these form factors at q2=0q^2=0 are: f^+_K(0)=0.67 \er{7}{8} , V(0)=1.01 \err{30}{13} , A_1(0)=0.70 \err{7}{10} , A_2(0)=0.66 \err{10}{15} , which are consistent with the most recent experimental world average values. We have also determined the q2q^2 dependence of the form factors, which we find to be reasonably well described by a simple pole-dominance model. Results for other form factors, including those relevant to the decays \dpi and \drho, are also given.Comment: 41 pages, uuencoded compressed postscript file containing 14 figures, LaTeX, Edinburgh Preprint 94/546 and Southampton Preprint SHEP 93/94-3

    Unter Mordverdacht: Differenzialdiagnose einer Arsenvergiftung

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    Zusammenfassung: Es wird ein Fall vorgestellt, der auf den ersten Blick an spektakuläre Arsenmorde der Vergangenheit anzuknüpfen scheint. Im Rahmen von Scheidungsstreitigkeiten zwischen einem 70-jährigen Mann und seiner knapp 30Jahre jüngeren Frau war es beim Betroffenen zu Symptomen einer Arsenvergiftung gekommen. Nach dem unerwarteten Tod seines Hundes hatte der Mann seinen Hausarzt aufgesucht, der bei einer Blutuntersuchung einen erhöhten Arsenspiegel feststellte. Bei chemisch-toxikologischen Analysen von Probenmaterial, das im Rahmen rechtsmedizinischer Untersuchungen der Betroffenen sowie einer Exhumierung des Hundes gewonnen wurde, fanden sich bei dem Mann und seiner Frau auffällig erhöhte Arsenspiegel. Die vorliegende Kasuistik unterstreicht eindrücklich die Wichtigkeit der Arsenspezifizierung in einem qualifizierten Labor im Fall einer erhöhten Arsenkonzentration in Probenmateria
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