18,856 research outputs found

    Cosmic e^\pm, \bar p, \gamma and neutrino rays in leptocentric dark matter models

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    Dark matter annihilation is one of the leading explanations for the recently observed e±e^\pm excesses in cosmic rays by PAMELA, ATIC, FERMI-LAT and HESS. Any dark matter annihilation model proposed to explain these data must also explain the fact that PAMELA data show excesses only in e±e^\pm spectrum but not in anti-proton. It is interesting to ask whether the annihilation mode into anti-proton is completely disallowed or only suppressed at low energies. Most models proposed have negligible anti-protons in all energy ranges. We show that the leptocentric U(1)B3LiU(1)_{B-3L_i} dark matter model can explain the e±e^\pm excesses with suppressed anti-proton mode at low energies, but at higher energies there are sizable anti-proton excesses. Near future data from PAMELA and AMS can provide crucial test for this type of models. Cosmic γ\gamma ray data can further rule out some of the models. We also show that this model has interesting cosmic neutrino signatures.Comment: Latex 20 pages and five figures. References adde

    Renormalization group improved pQCD prediction for Υ(1S)\Upsilon(1S) leptonic decay

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    The complete next-to-next-to-next-to-leading order short-distance and bound-state QCD corrections to Υ(1S)\Upsilon(1S) leptonic decay rate Γ(Υ(1S)+)\Gamma(\Upsilon(1S)\to \ell^+\ell^-) has been finished by Beneke {\it et al.} \cite{Beneke:2014qea}. Based on those improvements, we present a renormalization group (RG) improved pQCD prediction for Γ(Υ(1S)+)\Gamma(\Upsilon(1S)\to \ell^+\ell^-) by applying the principle of maximum conformality (PMC). The PMC is based on RG-invariance and is designed to solve the pQCD renormalization scheme and scale ambiguities. After applying the PMC, all known-type of β\beta-terms at all orders, which are controlled by the RG-equation, are resummed to determine optimal renormalization scale for its strong running coupling at each order. We then achieve a more convergent pQCD series, a scheme- independent and more accurate pQCD prediction for Υ(1S)\Upsilon(1S) leptonic decay, i.e. ΓΥ(1S)e+ePMC=1.2700.187+0.137\Gamma_{\Upsilon(1S) \to e^+ e^-}|_{\rm PMC} = 1.270^{+0.137}_{-0.187} keV, where the uncertainty is the squared average of the mentioned pQCD errors. This RG-improved pQCD prediction agrees with the experimental measurement within errors.Comment: 11 pages, 4 figures. Numerical results and discussions improved, references updated, to be published in JHE

    Superior lentiviral vectors designed for BSL-0 environment abolish vector mobilization.

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    Lentiviral vector mobilization following HIV-1 infection of vector-transduced cells poses biosafety risks to vector-treated patients and their communities. The self-inactivating (SIN) vector design has reduced, however, not abolished mobilization of integrated vector genomes. Furthermore, an earlier study demonstrated the ability of the major product of reverse transcription, a circular SIN HIV-1 vector comprising a single- long terminal repeat (LTR) to support production of high vector titers. Here, we demonstrate that configuring the internal vector expression cassette in opposite orientation to the LTRs abolishes mobilization of SIN vectors. This additional SIN mechanism is in part premised on induction of host PKR response to double-stranded RNAs comprised of mRNAs transcribed from cryptic transcription initiation sites around 3'SIN-LTR's and the vector internal promoter. As anticipated, PKR response following transfection of opposite orientation vectors, negatively affects their titers. Importantly, shRNA-mediated knockdown of PKR rendered titers of SIN HIV-1 vectors comprising opposite orientation expression cassettes comparable to titers of conventional SIN vectors. High-titer vectors carrying an expression cassette in opposite orientation to the LTRs efficiently delivered and maintained high levels of transgene expression in mouse livers. This study establishes opposite orientation expression cassettes as an additional PKR-dependent SIN mechanism that abolishes vector mobilization from integrated and episomal SIN lentiviral vectors

    Identification of miRNAs involved in fruit ripening in Cavendish bananas by deep sequencing

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    The most enriched pathways that were identified for the target genes. A total of 53 most enriched pathways of target gene annotated in this study. (XLS 41 kb
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