451 research outputs found

    Hadron yields from thermalized minijets at RHIC and LHC

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    We calculate the yields of pions, kaons, and ϕ\phi-mesons for RHIC and LHC energies assuming thermodynamical equilibration of the produced minijets, and using as input results from pQCD for the energy densities at midrapidity. In the calculation of the production of partons and of transverse energy one has to account for nuclear shadowing. By using two parametrizations for the gluon shadowing one derives energy densities differing strongly in magnitude. In this publication we link those perturbatively calculated energy densities of partons via entropy conservation in an ideal fluid to the hadron multiplicities at chemical freeze-out.Comment: Talk given at the International Europhysics Conference on High Energy Physics, EPS-HEP99, Tampere, Finland, July 1999, 3 page

    A computer aided teleoperator system Final report

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    Computer aided teleoperator system for remote handling task

    Hadron yields in Au+Au/Pb+Pb at RHIC and LHC from thermalized minijets

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    We calculate the yields of a variety of hadrons for RHIC and LHC energies assuming thermodynamical equilibration of the produced minijets, and using as input results from pQCD for the energy densities at midrapidity. In the calculation of the production of partons and of transverse energy one has to account for nuclear shadowing. By using two parametrizations for the gluon shadowing one derives energy densities differing strongly in magnitude. In this publication we link those perturbatively calculated energy densities of partons via entropy conservation in an ideal fluid to the hadron multiplicities at chemical freeze-out.Comment: 11 pages, 2 .eps figure

    Gluon- vs. Sea quark-Shadowing

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    We calculate the shadowing of sea quarks and gluons and show that the shadowing of gluons is {\it not} simply given by the sea quark shadowing, especially at small xx. The calculations are done in the lab frame approach by using the generalized vector meson dominance model. Here the virtual photon turns into a hadronic fluctuation long before the nucleus. The subsequent coherent interaction with more than one nucleon in the nucleus leads to the depletion σ(γA)<Aσ(γN)\sigma (\gamma^* A) < A\sigma (\gamma^* N) known as shadowing. A comparison of the shadowing of quarks to E665 data for 40Ca^{40}Ca and 207Pb^{207}Pb shows good agreement.Comment: 9 pages, 3 eps figure

    Colostrum effects on the gastrointestinal tract, and on nutritional, endocrine and metabolic parameters in neonatal calves

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    Abstract Newborn calves are characterised by marked cardio-respiratory, metabolic and endocrine changes which continue during ensuing weeks and months. Thus, although the somatotrophic axis is basically functioning in neonatal calves, it is not yet mature. The speed of the adaptations of the various traits differs widely. The ability to digest colostrum and milk requires specific structures and functions of the gastrointestinal tract. Colostrum composition exhibits major changes after the onset of lactation. Colostrum intake is important for passive immunity, but also for the provision of carbohydrates, lipids, proteins, minerals and vitamins. In addition, colostrum contains hormones, growth factors, cytokines, enzymes, polyamines and nucleotides, which in the neonatal calf can exert biological effects. Thus, insulin-like growth factor I, which in colostrum is present in high amounts, may enhance gastrointestinal tract development and function of neonatal calves. Colostrum should be ingested as soon as possible after birth for efficient and sufficient absorption not only of immunoglobulins, but apparently also of (essential and non-essential) fatty acids and fat-soluble vitamins (b-carotene, retinol and a-tocopherol). The pattern of essential amino acids and the glutamine / glutamate ratio in blood plasma also greatly depend on whether and when colostrum is fed. In addition, there are considerable effects on hormones (especially on concentrations of insulin, glucagon, insulin-like growth factor-I, including its binding proteins, and cortisol) that are dependent on time and amount of colostrum fed
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