1,290 research outputs found

    Changes in erythropoietin levels during space flight or space flight simulation

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    Two hundred and seventy samples from 24 subjects involved in 3 bedrest studies and from 3 subjects involved in Spacelab Mission Development Test 3 were assayed for erythropoietin (Ep), in an in vitro fetal mouse liver cell assay, and for ferritin using a commercially available immunoradiometric assay kit. No trends or significant changes in serum Ep were observed. Serum ferritin concentrations tended to increases slightly during the 'missions', reflecting a redirection of iron from the suppressed erythron into iron stores

    The nuclear contacts and short range correlations in nuclei

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    Atomic nuclei are complex strongly interacting systems and their exact theoretical description is a long-standing challenge. An approximate description of nuclei can be achieved by separating its short and long range structure. This separation of scales stands at the heart of the nuclear shell model and effective field theories that describe the long-range structure of the nucleus using a mean- field approximation. We present here an effective description of the complementary short-range structure using contact terms and stylized two-body asymptotic wave functions. The possibility to extract the nuclear contacts from experimental data is presented. Regions in the two-body momentum distribution dominated by high-momentum, close-proximity, nucleon pairs are identified and compared to experimental data. The amount of short-range correlated (SRC) nucleon pairs is determined and compared to measurements. Non-combinatorial isospin symmetry for SRC pairs is identified. The obtained one-body momentum distributions indicate dominance of SRC pairs above the nuclear Fermi-momentum.Comment: Accepted for publication in Physics Letters. 6 pages, 2 figure

    Spontaneous Breaking of Rotational Symmetry in Rotating Solitons - a Toy Model of Excited Nucleons with High Angular Momentum

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    We study the phenomenon of spontaneous breaking of rotational symmetry (SBRS) in the rotating solutions of two types of baby Skyrme models. In the first the domain is a two-sphere and in the other, the Skyrmions are confined to the interior of a unit disk. Numerical full-field results show that when the angular momentum of the Skyrmions increases above a certain critical value, the rotational symmetry of the solutions is broken and the minimal energy configurations become less symmetric. We propose a possible mechanism as to why SBRS is present in the rotating solutions of these models, while it is not observed in the `usual' baby Skyrme model. Our results might be relevant for a qualitative understanding of the non-spherical deformation of excited nucleons with high orbital angular momentum.Comment: RevTex, 9 pages, 9 figures. Added conten

    Measurement of transparency ratios for protons from short-range correlated pairs

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    Nuclear transparency, Tp(A), is a measure of the average probability for a struck proton to escape the nucleus without significant re-interaction. Previously, nuclear transparencies were extructed for quasi-elastic A(e,e'p) knockout of protons with momentum below the Fermi momentum, where the spectral functions are well known. In this paper we extract a novel observable, the transparency ratio, Tp(A)/T_p(12C), for knockout of high-missing-momentum protons from the breakup of short range correlated pairs (2N-SRC) in Al, Fe and Pb nuclei relative to C. The ratios were measured at momentum transfer Q^2 > 1.5 (GeV/c)^2 and x_B > 1.2 where the reaction is expected to be dominated by electron scattering from 2N-SRC. The transparency ratios of the knocked-out protons coming from 2N-SRC breakup are 20 - 30% lower than those of previous results for low missing momentum. They agree with Glauber calculations and agree with renormalization of the previously published transparencies as proposed by recent theoretical investigations. The new transparencies scale as A^-1/3, which is consistent with dominance of scattering from nucleons at the nuclear surface.Comment: 6 pages, 4 figure

    Constraints on the large-x d/u ratio from electron-nucleus scattering at x>1

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    Recently the ratio of neutron to proton structure functions F_2n/F_2p was extracted from a phenomenological correlation between the strength of the nuclear EMC effect and inclusive electron-nucleus cross section ratios at x>1. Within conventional models of nuclear smearing, this "in-medium correction" (IMC) extraction constrains the size of nuclear effects in the deuteron structure functions, from which the neutron structure function F_2n is usually extracted. The IMC data determine the resulting proton d/u quark distribution ratio, extrapolated to x=1, to be 0.23 +- 0.09 with a 90% confidence level. This is well below the SU(6) symmetry limit of 1/2 and significantly above the scalar diquark dominance limit of 0.Comment: 4 pages, 3 figure

    Short Range Correlations and the EMC Effect

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    This paper shows quantitatively that the magnitude of the EMC effect measured in electron deep inelastic scattering (DIS) at intermediate xBx_B, 0.35xB0.70.35\le x_B\le 0.7, is linearly related to the Short Range Correlation (SRC) scaling factor obtained from electron inclusive scattering at xB1.x_B\ge 1.. The observed phenomenological relationship is used to extract the ratio of the deuteron to the free pnpn pair cross sections, the DIS cross section for a free neutron, and F2n/F2pF_2^n/F_2^p, the ratio of the free neutron to free proton structure functions. We speculate that the observed correlation is because both the EMC effect and SRC are dominated by the high virtuality (high momentum) nucleons in the nucleus.Comment: 5 pages, 2 figures, minor changes for PRL acceptance, reference 12 correcte

    Hexagonal Structure of Baby Skyrmion Lattices

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    We study the zero-temperature crystalline structure of baby Skyrmions by applying a full-field numerical minimization algorithm to baby Skyrmions placed inside different parallelogramic unit-cells and imposing periodic boundary conditions. We find that within this setup, the minimal energy is obtained for the hexagonal lattice, and that in the resulting configuration the Skyrmion splits into quarter-Skyrmions. In particular, we find that the energy in the hexagonal case is lower than the one obtained on the well-studied rectangular lattice, in which splitting into half-Skyrmions is observed.Comment: RevTeX, 7 pages, 6 figure

    Perancangan Logo & Corporate Identity Hotel Gowin Bali

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    Logo dan corporate identity merupakan salah satu faktor yang sangat penting dalam membangun identitas atau citra sebuah Perusahaan yang dapat menentukan bagaimana nasib suatu Perusahaan, baik dalam hal citranya di mata masyarakat maupun berkembang tidaknya suatu Perusahaan. Melihat betapa pentingnya peranan logo dan corporate identity, maka hotel Gowin yang akan segera membuka USAha dalam bidang perhotelan tentu juga memerlukannya. Berlokasi di wilayah Bali yang penuh dengan persaingan ketat dalam bidang bisnis pariwisata, membuat hotel Gowin perlu menonjolkan keistimewaannya yang dapat diwujudkan dalam bentuk lambang identitas logo dan corporate identity, sehingga mampu bersaing dan tidak kalah bersaing dengan hotel-hotel lainnya. Logo dan corporate identity hotel Gowin dirancang sesuai dengan visi misi dan citra Perusahaan yang ingin ditampilkan sehingga dihasilkan logo dan corporate identity yang modern namun tetap tidak meninggalkan ciri khas tradisional khas Bali
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