176 research outputs found

    Leptoproduction of Heavy Quarks II -- A Unified QCD Formulation of Charged and Neutral Current Processes from Fixed-target to Collider Energies

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    A unified QCD formulation of leptoproduction of massive quarks in charged current and neutral current processes is described. This involves adopting consistent factorization and renormalization schemes which encompass both vector-boson-gluon-fusion (flavor creation) and vector-boson-massive-quark-scattering (flavor excitation) production mechanisms. It provides a framework which is valid from the threshold for producing the massive quark (where gluon-fusion is dominant) to the very high energy regime when the typical energy scale \mu is much larger than the quark mass m_Q (where the quark-scattering should be prevalent). This approach effectively resums all large logarithms of the type (alpha_s(mu) log(mu^2/m_Q^2)^n which limit the validity of existing fixed-order calculations to the region mu ~ O(m_Q). We show that the (massive) quark-scattering contribution (after subtraction of overlaps) is important in most parts of the (x, Q) plane except near the threshold region. We demonstrate that the factorization scale dependence of the structure functions calculated in this approach is substantially less than those obtained in the fixed-order calculations, as one would expect from a more consistent formulation.Comment: LaTeX format, 29 pages, 11 figures. Revised to make auto-TeX-abl

    NLO Higgs boson production plus one and two jets using the POWHEG BOX, MadGraph4 and MCFM

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    We present a next-to-leading order calculation of Higgs boson production plus one and two jets via gluon fusion interfaced to shower Monte Carlo programs, implemented according to the POWHEG method. For this implementation we have used a new interface of the POWHEG BOX with MadGraph4, that generates the codes for generic Born and real processes automatically. The virtual corrections have been taken from the MCFM code. We carry out a simple phenomenological study of our generators, comparing them among each other and with fixed next-to-leading order results.Comment: 27 pages, 21 figure

    Priming Immunization with DNA Augments Immunogenicity of Recombinant Adenoviral Vectors for Both HIV-1 Specific Antibody and T-Cell Responses

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    Induction of HIV-1-specific T-cell responses relevant to diverse subtypes is a major goal of HIV vaccine development. Prime-boost regimens using heterologous gene-based vaccine vectors have induced potent, polyfunctional T cell responses in preclinical studies.The first opportunity to evaluate the immunogenicity of DNA priming followed by recombinant adenovirus serotype 5 (rAd5) boosting was as open-label rollover trials in subjects who had been enrolled in prior studies of HIV-1 specific DNA vaccines. All subjects underwent apheresis before and after rAd5 boosting to characterize in depth the T cell and antibody response induced by the heterologous DNA/rAd5 prime-boost combination.rAd5 boosting was well-tolerated with no serious adverse events. Compared to DNA or rAd5 vaccine alone, sequential DNA/rAd5 administration induced 7-fold higher magnitude Env-biased HIV-1-specific CD8(+) T-cell responses and 100-fold greater antibody titers measured by ELISA. There was no significant neutralizing antibody activity against primary isolates. Vaccine-elicited CD4(+) and CD8(+) T-cells expressed multiple functions and were predominantly long-term (CD127(+)) central or effector memory T cells and that persisted in blood for >6 months. Epitopes mapped in Gag and Env demonstrated partial cross-clade recognition.Heterologous prime-boost using vector-based gene delivery of vaccine antigens is a potent immunization strategy for inducing both antibody and T-cell responses.ClinicalTrials.gov NCT00102089, NCT00108654

    Diversity and Mega-Targets of Selection from the Characterization of a Barley Collection

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    Germplasm exchange is essential for assuring genetic gain in a breeding program. Two aspects of breeding programs are relevant to making them compatible for germplasm exchange: the amount of genetic diversity within programs and the identifi cation of breeding programs with similar breeding objectives and environments of selection (i.e., mega-targets of selection). The objective of this study was to develop a data-driven method to group breeding programs likely to be compatible for germplasm exchange and to use phenotypic characterization data of barley (Hordeum vulgare L.) from breeding programs to illustrate this method. In two locations in Uruguay we evaluated 20 traits in 353 genotypes of barley from 23 private and public breeding programs distributed worldwide. We found signifi cant amounts of genetic diversity for all traits, but differences in diversity among programs for only seven traits. We identifi ed programs with high (Western Australia Department of Agriculture; University of Saskatchewan; and Svalöf Weibull Ab, Sweden) and low diversity (winter program of Osijek Agricultural Institute, Croatia; spring program of Osijek Agricultural Institute, Croatia; Saatzucht Josef Breun, Germany; Busch Agricultural Resources; USDA-ARS, Aberdeen, ID; and University of Minnesota). We developed a methodology that groups programs with similar performance and response to the environments. We used the methodology to group the 23 breeding programs of barley into sets that might benefi t most from germplasm exchange. The identifi cation of compatible programs for germplasm exchange could be relevant for improving genetic gains in breeding programs
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