8,938 research outputs found

    The H→bsˉH\rightarrow b\bar{s} decay and its implication for the vector-like singlet fermion model

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    The decay width H→bsˉH\rightarrow b\bar{s} is firstly evaluated at leading order perturbation theory in the standard model. The result suggests that it is difficult to observe this mode because of the small width compared with other decays of the Higgs boson. Then based on the vector-like singlet model, assuming that the top partner only mixes with the third generation quark, we consider the contribution from coupling of top quark to its vector-like singlet partner. Further results show that the width of H→bsˉH\rightarrow b\bar{s} may rise to an extent to which the LHC experiments can accesses.Comment: 21 pages, 6 figure

    New predictions on the mass of the 1−+1^{-+} light hybrid meson from QCD sum rules

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    We calculate the coefficients of the dimension-8 quark and gluon condensates in the current-current correlator of 1−+1^{-+} light hybrid current gqˉ(x)γνiGμν(x)q(x)g\bar{q}(x)\gamma_{\nu}iG_{\mu\nu}(x)q{(x)}. With inclusion of these higher-power corrections and updating the input parameters, we re-analyze the mass of the 1−+1^{-+} light hybrid meson from Monte-Carlo based QCD sum rules. Considering the possible violation of factorization of higher dimensional condensates and variation of ⟨g3G3⟩\langle g^3G^3\rangle, we obtain a conservative mass range 1.72--2.60\,GeV, which favors π1(2015)\pi_{1}(2015) as a better hybrid candidate compared with π1(1600)\pi_{1}(1600) and π1(1400)\pi_{1}(1400).Comment: 12pages, 2 figures, the version appearing in JHE

    Reduced glutamine synthetase activity alters the fecundity of female Bactrocera dorsalis (Hendel)

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    Glutamine synthetase (GS) is a key enzyme in glutamine synthesis and is associated with multiple physiological processes in insects, such as embryonic development, heat shock response, and fecundity regulation. However, little is known about the influence of GS on female fecundity in the oriental fruit fly, Bactrocera dorsalis. Based on the cloning of BdGSs, mitochondrial BdGSm and cytoplasmic BdGSc, we determined their expressions in the tissues of adult B. dorsalis. BdGSm was highly expressed in the fat body, while BdGSc was highly expressed in the head and midgut. Gene silencing by RNA interference against two BdGSs isoforms suppressed target gene expression at the transcriptional level, leading to a reduced ovarian size and lower egg production. The specific inhibitor L-methionine S-sulfoximine suppressed enzyme activity, but only the gene expression of BdGSm was suppressed. A similar phenotype of delayed ovarian development occurred in the inhibitor bioassay. Significantly lower expression of vitellogenin and vitellogenin receptor was observed when GS enzyme activity was suppressed. These data illustrate the effects of two GS genes on adult fecundity by regulating vitellogenin synthesis in different ways

    An organogenesis network-based comparative transcriptome analysis for understanding early human development in vivo and in vitro

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    <p>Abstract</p> <p>Background</p> <p>Integrated networks hold great promise in a variety of contexts. In a recent study, we have combined expression and interaction data to identify a putative network underlying early human organogenesis that contains two modules, the stemness-relevant module (hStemModule) and the differentiation-relevant module (hDiffModule). However, owing to its hypothetical nature, it remains unclear whether this network allows for comparative transcriptome analysis to advance our understanding of early human development, both <it>in vivo </it>and <it>in vitro</it>.</p> <p>Results</p> <p>Based on this integrated network, we here report comparisons with the context-dependent transcriptome data from a variety of sources. By viewing the network and its two modules as gene sets and conducting gene set enrichment analysis, we demonstrate the network's utility as a quantitative monitor of the stem potential <it>versus </it>the differentiation potential. During early human organogenesis, the hStemModule reflects the generality of a gradual loss of the stem potential. The hDiffModule indicates the stage-specific differentiation potential and is therefore not suitable for depicting an extended developmental window. Processing of cultured cells of different types further revealed that the hStemModule is a general indicator that distinguishes different cell types in terms of their stem potential. In contrast, the hDiffModule cannot distinguish between differentiated cells of different types but is able to predict differences in the differentiation potential of pluripotent cells of different origins. We also observed a significant positive correlation between each of these two modules and early embryoid bodies (EBs), which are used as <it>in vitro </it>differentiation models. Despite this, the network-oriented comparisons showed considerable differences between the developing embryos and the EBs that were cultured <it>in vitro </it>over time to try to mimic <it>in vivo </it>processes.</p> <p>Conclusions</p> <p>We strongly recommend the use of these two modules either when pluripotent cell types of different origins are involved or when the comparisons made are constrained to the in <it>vivo </it>embryos during early human organogenesis (and an equivalent <it>in vitro </it>differentiation models). Network-based comparative transcriptome analysis will contribute to an increase in knowledge about human embryogenesis, particularly when only transcriptome data are currently available. These advances will add an extra dimension to network applications.</p

    Nonlinear Hall Effects in Strained Twisted Bilayer WSe2_2

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    Recently, it has been pointed out that the twisting of bilayer WSe2_2 would generate topologically non-trivial flat bands near the Fermi energy. In this work, we show that twisted bilayer WSe2_2 (tWSe2_2) with uniaxial strain exhibits a large nonlinear Hall (NLH) response due to the non-trivial Berry curvatures of the flat bands. Moreover, the NLH effect is greatly enhanced near the topological phase transition point which can be tuned by a vertical displacement field. Importantly, the nonlinear Hall signal changes sign across the topological phase transition point and provides a way to identify the topological phase transition and probe the topological properties of the flat bands. The strong enhancement and high tunability of the NLH effect near the topological phase transition point renders tWSe2_2 and related moire materials new platforms for rectification and second harmonic generations.Comment: 5 pages, 3 figures. Comments are welcom
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