1,117 research outputs found

    Probing the Perturbative NLO Parton Evolution in the Small-xx Region

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    A dedicated test of the perturbative QCD NLO parton evolution in the very small-xx region is performed. We find a good agreement with recent precision HERA-data for F2p(x,Q2)F_2^p(x,Q^2), as well as with the present determination of the curvature of F2pF_2^p. Characteristically, perturbative QCD evolutions result in a positive curvature which increases as xx decreases. Future precision measurements in the very small xx-region, x<104x<10^{-4}, could provide a sensitive test of the range of validity of perturbative QCDComment: Revised version, to appear in EPJ

    Salinization dynamics in irrigated soils of the Svetloyarsk irrigation system, Volgograd oblast

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    On the basis of soil surveys performed by the Volgograd hydrogeological reclamation expedition in 1998 and 2006, published data, and original materials obtained by the authors, the dynamics of soil salinization within the Svetloyarsk irrigation system in Volgograd oblast during the irrigation and post-irrigation periods have been traced. It is found that high irrigation rates under conditions of poor drainage and closed drainage basins upon both shallow (within the Caspian Lowland) and relatively deep (on the Ergeni Upland) occurrence of saline groundwater and the presence of natural salts in the soils and subsoils lead to the rise in the groundwater level above the critical level and the development of secondary salinization in the previously surfacesaline, deeply saline, and even nonsaline soils. During the post-irrigation period (15-18 years) under modern climatic conditions, the groundwater level has been descending to a depth of more than 3 m, and the degree of salinity in the upper meter of light chestnut and meadow-chestnut soils has decreased owing to the leaching of salts with atmospheric precipitation

    Psychometric Findings for a Spanish Translation of the Diabetes Self-Management Profile (DSMP-Parent-Sp)

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    OBJECTIVE: Few validated measures exist to evaluate self-management of diabetes in families with limited English proficiency. The present study evaluated the psychometric properties and the factorial equivalence of a Spanish translation of the parent report version of the Diabetes Self-Management Profile (DSMP-Parent-Sp). RESEARCH DESIGN AND METHODS: Hispanic families of youth (mean 13.7 years old) with type 1 diabetes were recruited from three clinics in South Florida and represented a wide range of nationalities and acculturation levels. A total of 127 parents reported on their child\u27s self-management behaviors using either the original DSMP-Parent (59.8%) or the DSMP-Parent-Sp (40.2%). In addition, youth reported their self-management using the original DSMP in English, and physicians rated their perceptions of the youth\u27s self-management. Glycemic control was indexed by A1C in the past 3 months and collected from medical chart review. RESULTS: Item analysis confirmed that the DSMP-Parent-Sp items related to the overall composite score in expected ways, and internal consistency estimates were adequate. Paired correlations demonstrated strong parent-child concordance and a significant relationship with physician perceptions of self-management. Evidence of concurrent and convergent validity, as well as strict factorial invariance, was demonstrated. CONCLUSIONS: These preliminary findings indicate that the DSMP-Parent-Sp is a reliable and valid parent report measure of the diabetes self-management behaviors of Hispanic youths. In addition, there is preliminary evidence that the translated measure may be considered equivalent to the original English measure when used to measure self-management in Hispanic youth with diabetes

    Observation of the TeV gamma-ray source MGRO J1908+06 with ARGO-YBJ

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    The extended gamma ray source MGRO J1908+06, discovered by the Milagro air shower detector in 2007, has been observed for about 4 years by the ARGO-YBJ experiment at TeV energies, with a statistical significance of 6.2 standard deviations. The peak of the signal is found at a position consistent with the pulsar PSR J1907+0602. Parametrizing the source shape with a two-dimensional Gauss function we estimate an extension \sigma = 0.49 \pm 0.22 degrees, consistent with a previous measurement by the Cherenkov Array H.E.S.S.. The observed energy spectrum is dN/dE = 6.1 \pm 1.4 \times 10^-13 (E/4 TeV)^{-2.54 \pm 0.36} photons cm^-2 s^-1 TeV^-1, in the energy range 1-20 TeV. The measured gamma ray flux is consistent with the results of the Milagro detector, but is 2-3 times larger than the flux previously derived by H.E.S.S. at energies of a few TeV. The continuity of the Milagro and ARGO-YBJ observations and the stable excess rate observed by ARGO-YBJ along 4 years of data taking support the identification of MGRO J1908+06 as the steady powerful TeV pulsar wind nebula of PSR J1907+0602, with an integrated luminosity above 1 TeV about 1.8 times the Crab Nebula luminosity.Comment: 6 pages, accepted for pubblication by ApJ. Replaced to correct the author lis

    Planck intermediate results X : Physics of the hot gas in the Coma cluster

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    Planck intermediate results I : Further validation of new Planck clusters with XMM-Newton

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