1,682 research outputs found

    B Meson Transitions into Higher Mass Charmed Resonances

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    We use QCD sum rules to estimate the universal form factors describing the semileptonic B decays into excited charmed resonances, such as the 11^- and 22^- states D1D_1^{*} and D2D_2^{*} belonging to the sP=3/2s_\ell^P={3/2}^- heavy quark doublet, and the 22^- and 33^- states D2D_2^{*\prime} and D3D_3 belonging to the s_\ell^P={5\2}^- doublet.Comment: LaTex, 14 pages, 1 figur

    Eta-nucleon coupling constant in QCD with SU(3) symmetry breaking

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    We study the η\etaNN coupling constant using the method of QCD sum rules starting from the vacuum-to-eta correlation function of the interpolating fields of two nucleons. The matrix element of this correlation has been taken with respect to nucleon spinors to avoid unwanted pole contribution. The SU(3)-flavor symmetry breaking effects have been accounted for via the η\eta-mass, s-quark mass and eta decay constant to leading order. Out of the four sum rules obtained by taking the ratios of the two sum rules in conjunction with the two sum rules in nucleon mass, three are found to give mutually consistent results. We find the SU(3) breaking effects significant, as large as 50% of the SU(3) symmetric part.Comment: 13 pages, 12 figure

    Heavy Quarkonia Survival in Potential Model

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    We investigate the quarkonia correlators in QCD with no light quarks within a potential model with different screened potentials. Our results for the temperature dependence of the charmonium and bottomonium correlators are qualitatively consistent with existing and preliminary lattice results. We identify however, a much reacher structure in the correlators than the one seen on the lattice

    Calculation of coupling constant g_phi-pi-gamma in QCD sum rules

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    The coupling constant of g_phi-pi-gamma decay is calculated in the method of QCD sum rules. A comparison of our prediction on the coupling constant with the result obtained from analysis of the experimental data is performed.Comment: 6 pages, 3 figure

    Characterizing the sublethal effects of SmartStax PRO dietary exposure on life history traits of the western corn rootworm, \u3ci\u3e Diabrotica virgifera virgifera\u3c/i\u3e LeConte

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    The western corn rootworm (WCR), Diabrotica virgifera virgifera LeConte, is an economically important pest of field corn (Zea mays L.) across the United States (U.S.) Corn Belt. Repeated use of transgenic hybrids expressing Bacillus thuringiensis (Bt) proteins has selected for field-evolved resistance to all current rootworm-active Bt proteins. The newest product available for WCR management is SmartStax® PRO, a rootworm-active pyramid containing Cry3Bb1, Cry34/35Ab1 [now reclassified as Gpp34Ab1/Tpp35Ab1] and a new mode of action, DvSnf7 dsRNA. Understanding the fitness of adult WCR after dietary exposure to SmartStax® PRO will identify potential impacts on WCR population dynamics and inform efforts to optimize resistance management strategies. Therefore, the objective of the present study was to characterize the effect of SmartStax® PRO dietary exposure on WCR life history traits. Adult WCR were collected during 2018 and 2019 from emergence tents placed over replicated field plots of SmartStax® PRO or non-rootworm Bt corn at a site with a history of rootworm-Bt trait use and suspected resistance to Cry3Bb1 and Cry34/35Ab1. Adult survival was reduced by 97.1–99.7% in SmartStax® PRO plots relative to the non-rootworm Bt corn plots during the study. Individual male/female pairs were fed different diets of ear tissue to simulate lifetime or adult exposure. Life history parameters measured included adult longevity, adult head capsule width, lifetime female egg production, and egg viability. Results indicate that lifetime or adult exposure to SmartStax® PRO significantly reduced adult longevity and lifetime egg production. Larval exposure to SmartStax® PRO significantly reduced WCR adult size. Results from this study collectively suggest that SmartStax® PRO may negatively impact WCR life history traits, which may lead to reduced population growth when deployed in an area with WCR resistance to Bt traits

    Stability from Structure: Metabolic Networks Are Unlike Other Biological Networks

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    In recent work, attempts have been made to link the structure of biochemical networks to their complex dynamics. It was shown that structurally stable network motifs are enriched in such networks. In this work, we investigate to what extent these findings apply to metabolic networks. To this end, we extend a previously proposed method by changing the null model for determining motif enrichment, by using interaction types directly obtained from structural interaction matrices, by generating a distribution of partial derivatives of reaction rates and by simulating enzymatic regulation on metabolic networks. Our findings suggest that the conclusions drawn in previous work cannot be extended to metabolic networks, that is, structurally stable network motifs are not enriched in metabolic networks

    QCD sum rules with finite masses

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    The concept of QCD sum rules is extended to bound states composed of particles with finite mass such as scalar quarks or strange quarks. It turns out that mass corrections become important in this context. The number of relevant corrections is analyzed in a systematic discussion of the IR- and UV-divergencies, leading in general to a finite number of corrections. The results are demonstrated for a system of two massless quarks and two heavy scalar quarks.Comment: 15 pages, including two pictures to be found in an extra file. Latex neads epsf.st

    Stump sensibility in children with upper limb reduction deficiency

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    Phenomenology of BsB_s Decays

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    Using the QCD sum rules technique we study several aspects of the phenomenology of the b-flavoured strange meson Bs0B_s^0. In particular, we evaluate the mass of the particle, the leptonic constant and the form factors of the decays Bs0Ds+νˉ\overline {B_s^0} \to D^{+}_s \ell^- \bar\nu, Bs0Ds+νˉ\overline {B_s^0} \to D^{*+}_s \ell^- \bar\nu, Bs0K+νˉ\overline {B_s^0} \to K^{*+} \ell^- \bar\nu. We also calculate, in the factorization approximation, a number of two-body non leptonic Bs0\overline {B_s^0} decays.Comment: 19 pages, 2 figures (not included) available upon request, LaTex, BARI-TH/93-139, UTS-DFT-93-1
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