1,351 research outputs found

    Molecular Characterization of trans -Golgi p230: a human peripheral membrane protein encoded by a gene on chromosome 6p12-22 contains extensive coiled-coil α-helical domains and a Granin Motif

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    Using autoantibodies from a Sjögren's syndrome patient, we have previously identified a 230-kDa peripheral membrane protein associated with the cytosolic face of the trans-Golgi (Kooy, J., Toh, B. H., Pettitt, J. M., Erlich, R. and Gleeson, P. A. (1992) J. Biol. Chem. 267, 20255-20263). Here we report the molecular cloning and sequence analysis of human p230 and the localization of its gene to chromosome 6p12 22. Partial cDNA clones, isolated from a HeLa cell cDNA library using autoantibodies, were used to obtain additional cDNAs, which together span 7695 base pairs (bp). The p230 mRNA is approximately 7.7 kilobases. Two alternatively spliced mRNAs for p230 were detected. These differed by 21- and 63-bp insertions in the 3'-sequence, resulting in differences in amino acid sequence at the carboxyl terminus. The predicted 261-kDa protein is highly hydrophilic with 17-20% homology with many proteins containing coiled-coil domains. Apart from two proline-rich regions (amino acids 1-117 and 239-270), p230 contains a very high frequency of heptad repeats, characteristic of alpha-helices that form dimeric coiled-coil structures. p230 also includes the sequence ESLALEELEL (amino acids 538-546), a motif found in the granin family of acidic proteins present in secretory granules of neuroendocrine cells. This is the first report of a cytosolic Golgi protein containing a granin motif. The structural characteristics of p230 indicate that it may play a role in vesicular transport from the trans-Golgi

    Informationsbedarf und -austausch in Netzwerken kleiner und mittelständischer Unternehmen

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    Untemehmensnetzwerke für kleine und mittelständische Unternehmen werden heute als ein wichtiges Werkzeug für die Erhöhung der Konkurrenzfähigkeit auf Märkten betrachtet. Der Austausch von Informationen ist Kembestandteil solcher Netzwerke. Ein wesentlicher Aspekt des Austausches ist dabei - neben dem Informationsbedarf, der Bereitschaft zur Bereitstellung und der Möglichkeiten zur Auswertung von Informationen - das Ziel, das durch den Informationsaustausch verfolgt wird. In welchem Umfang sich ein Unternehmen in ein Bündnis integriert, wird deshalb maßgeblich durch seine Ziele und die unter diesem Blickwinkel in das Untemehmensnetzwerk gesetzten Nutzenerwartungen bestimmt. Die Organisationsstruktur der Netzwerke ist eng verbunden mit den Zielen, die diese Netze verfolgen. Unter anderem sind die Vorteile einer zentralen gegen die einer dezentralen Verwaltung abzuwägen. Wichtig hierfür sind die Ziele des einzelnen Unternehmens und des Netzwerkes. Der vorliegende Beitrag untersucht aus theoretischer Sicht, inwieweit sich aus den Untemehmenszielen, speziell kleiner oder mittelständischer Unternehmen, eine Entscheidung für oder gegen den Eintritt in ein Untemehmensnetzwerk ableiten läßt

    Proton and Pion Production Relative to the Reaction Plane in Au + Au Collisions at AGS Energies

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    Results are presented of an analysis of proton and charged pion azimuthal distributions measured with respect to the reaction plane in Au + Au collisions at a beam momentum of about 11 AGeV/c. The azimuthal anisotropy is studied as a function of particle rapidity and transverse momentum for different centralities of the collisions. The triple differential (in rapidity, transverse momentum, and azimuthal angle) distributions are reconstructed. A comparison of the results with a previous analysis of charged particle and transverse energy flow as well as with model predictions is presented.Comment: 23 pages (LaTeX), 12 figure

    Two-pion correlations in Au+Au collisions at 10.8 GeV/c per nucleon

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    Two-particle correlation functions for positive and negative pions have been measured in Au+Au collisions at 10.8~GeV/c per nucleon. The data were analyzed using one- and three-dimensional correlation functions. From the results of the three-dimensional fit the phase space density of pions was calculated. It is consistent with local thermal equilibrium.Comment: 5 pages RevTeX (including 3 Figures

    Cross sections and double-helicity asymmetries of midrapidity inclusive charged hadrons in p+p collisions at sqrt(s)=62.4 GeV

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    Unpolarized cross sections and double-helicity asymmetries of single-inclusive positive and negative charged hadrons at midrapidity from p+p collisions at sqrt(s)=62.4 GeV are presented. The PHENIX measurements for 1.0 < p_T < 4.5 GeV/c are consistent with perturbative QCD calculations at next-to-leading order in the strong coupling constant, alpha_s. Resummed pQCD calculations including terms with next-to-leading-log accuracy, yielding reduced theoretical uncertainties, also agree with the data. The double-helicity asymmetry, sensitive at leading order to the gluon polarization in a momentum-fraction range of 0.05 ~< x_gluon ~< 0.2, is consistent with recent global parameterizations disfavoring large gluon polarization.Comment: PHENIX Collaboration. 447 authors, 12 pages, 5 figures, 5 tables. Submitted to Physical Review

    The stellar content of OMC 2/3

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    We have revisited the stellar content of OMC 2 and OMC 3 by means of MIR imaging and NIR photometry; in addition, we have extended the existing (sub)mm maps by a huge 1200 micron map obtained with SIMBA showing new sources and filamentary features for the first time at that wavelength. The MIR data reveal 43 new sources at N and Q which are partly associated with dense condensations at millimetre wavelengths. Six close binary sources could be resolved at locations where existing (sub)mm maps only show single emission peaks; three of them are classified as early (B-type) systems, one of them is compatible with type K while the remaining two seem to be T Tauri stars. Furthermore, the MIR images indicate the existence of separate circumstellar discs in the K-binary system. NIR colour-colour and colour-magnitude diagrams obtained from 2MASS data are examined to explore the physical properties of the sources and to derive the distribution of J luminosities. There is a clear decrease in luminosity and thus in stellar mass when going from South to North. Likewise, there is an anti-correlation between Class I and II objects in both regions: while OMC 2 contains twice as much Class II objects compared to Class I, the situation is reversed in OMC 3.Comment: 12 pages, 13 figures, accepted for A&A (full version available at http://www.astro.rub.de/nielbock/research

    Inclusive cross section and double helicity asymmetry for pi^0 production in p+p collisions at sqrt(s) = 62.4 GeV

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    The PHENIX experiment presents results from the RHIC 2006 run with polarized proton collisions at sqrt(s) = 62.4 GeV for inclusive pi^0 production at mid-rapidity. Unpolarized cross section results are measured for transverse momenta p_T = 0.5 to 7 GeV/c. Next-to-leading order perturbative quantum chromodynamics calculations are compared with the data, and while the calculations are consistent with the measurements, next-to-leading logarithmic corrections improve the agreement. Double helicity asymmetries A_LL are presented for p_T = 1 to 4 GeV/c and probe the higher range of Bjorken_x of the gluon (x_g) with better statistical precision than our previous measurements at sqrt(s)=200 GeV. These measurements are sensitive to the gluon polarization in the proton for 0.06 < x_g < 0.4.Comment: 387 authors from 63 institutions, 10 pages, 6 figures, 1 table. Submitted to Physical Review D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Inclusive cross section and single-transverse-spin asymmetry for very forward neutron production in polarized p+p collisions at sqrt(s)=200 GeV

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    The energy dependence of the single-transverse-spin asymmetry, A_N, and the cross section for neutron production at very forward angles were measured in the PHENIX experiment at RHIC for polarized p+p collisions at sqrt(s)=200 GeV. The neutrons were observed in forward detectors covering an angular range of up to 2.2 mrad. We report results for neutrons with momentum fraction of x_F=0.45 to 1.0. The energy dependence of the measured cross sections were consistent with x_F scaling, compared to measurements by an ISR experiment which measured neutron production in unpolarized p+p collisions at sqrt(s)=30.6--62.7 GeV. The cross sections for large x_F neutron production for p+p collisions, as well as those in e+p collisions measured at HERA, are described by a pion exchange mechanism. The observed forward neutron asymmetries were large, reaching A_N=-0.08+/-0.02 for x_F=0.8; the measured backward asymmetries, for negative x_F, were consistent with zero. The observed asymmetry for forward neutron production is discussed within the pion exchange framework, with interference between the spin-flip amplitude due to the pion exchange and nonflip amplitudes from all Reggeon exchanges. Within the pion exchange description, the measured neutron asymmetry is sensitive to the contribution of other Reggeon exchanges even for small amplitudes.Comment: 383 authors, 16 pages, 18 figures, 6 tables. Submitted to Phys. Rev. D. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Centrality dependence of charged hadron production in deuteron+gold and nucleon+gold collisions at sqrt(s_NN)=200 GeV

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    We present transverse momentum (p_T) spectra of charged hadrons measured in deuteron-gold and nucleon-gold collisions at \sqrts = 200 GeV for four centrality classes. Nucleon-gold collisions were selected by tagging events in which a spectator nucleon was observed in one of two forward rapidity detectors. The spectra and yields were investigated as a function of the number of binary nucleon-nucleon collisions, \nu, suffered by deuteron nucleons. A comparison of charged particle yields to those in p+p collisions show that the yield per nucleon-nucleon collision saturates with \nu for high momentum particles. We also present the charged hadron to neutral pion ratios as a function of p_T.Comment: 330 authors, 15 pages text, 16 figures, 3 tables. Submitted to Phys. Rev. Lett. v2 has minor changes to reflect revisions during review process. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm
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