1,539 research outputs found

    The Υ(1S)\Upsilon(1S) leptonic decay using the principle of maximum conformality

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    In the paper, we study the Υ(1S)\Upsilon(1S) leptonic decay width Γ(Υ(1S)→ℓ+ℓ−)\Gamma(\Upsilon(1S)\to \ell^+\ell^-) by using the principle of maximum conformality (PMC) scale-setting approach. The PMC adopts the renormalization group equation to set the correct momentum flow of the process, whose value is independent to the choice of the renormalization scale and its prediction thus avoids the conventional renormalization scale ambiguities. Using the known next-to-next-to-next-to-leading order perturbative series together with the PMC single scale-setting approach, we do obtain a renormalization scale independent decay width, ΓΥ(1S)→e+e−=1.262−0.175+0.195\Gamma_{\Upsilon(1S) \to e^+ e^-} = 1.262^{+0.195}_{-0.175} keV, where the error is squared average of those from αs(MZ)=0.1181±0.0011\alpha_s(M_{Z})=0.1181\pm0.0011, mb=4.93±0.03m_b=4.93\pm0.03 GeV and the choices of factorization scales within ±10%\pm 10\% of their central values. To compare with the result under conventional scale-setting approach, this decay width agrees with the experimental value within errors, indicating the importance of a proper scale-setting approach.Comment: 6 pages, 4 figure

    Investigation on dynamic characteristics of mechanical assembly

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    Mechanical assembly is important process affecting product dynamic quality. To completely inspect assembly quality, dynamic characteristic analysis is necessary. Based on substructuring dynamic analysis, this paper theoretically analyzes the changes of dynamic characteristics due to assembling process. Assembly coupling dynamic stiffness computed by inverse substructuring analysis is considered as a critical measure on the changes. The results obtained have been well validated by a lumped-parameter model for two-level of substructures

    Molecular cloning and characterization of a novel Cys2/His2-type zinc finger protein gene from chrysanthemum

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    A novel member of the Cys2/His2-type zinc finger protein gene family, designated DgZFP3, was isolated from chrysanthemum by rapid amplification of cDNA ends (RACE). The DgZFP3 encodes a protein of 248 amino acids, including two conserved Cys2/His2-type zinc finger motifs with a plant-specific QALGGH motif in each zinc finger domain, a B-box (KXKRSKRXR) domain in the N-terminal region as a putative nuclear localization signal (NLS), a L-box (EXEXXAXCLXXL) and an EAR-box (DLNL) at C-terminus. Subcellular localization showed the presence of DgZFP3 in the nucleus. The transcript of DgZFP3 was enriched in roots and leaves than in stems and flowers of the adult chrysanthemum plants. Expression patterns revealed that DgZFP3 was strongly induced by NaCl, drought, cold and abscisic acid (ABA) treatment in the seedlings. We argued that DgZFP3 is a new member of the Cys2/His2-type zinc finger protein gene family, and it may be involved in the plant responses to various stresses.Keywords: Chrysanthemum, DgZFP3, gene expression, Cys2/His2-type zinc finger protei

    Deletion of the V2 vasopressin receptor gene in two Chinese patients with nephrogenic diabetes insipidus

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    BACKGROUND: Congenital nephrogenic diabetes insipidus (NDI) is a rare X-linked inherited disorder characterized by the excretion of large volumes of diluted urine and caused by mutations in arginine vasopressin receptor 2 (AVPR2) gene. To investigate the mutation of AVPR2 gene in a Chinese family with congenital NDI, we screened AVPR2 gene in two NDI patients and eight family members by PCR amplification and direct sequencing. RESULTS: Five specific fragments, covering entire coding sequence and their flanking intronic sequences of AVPR2 gene, were not observed in both patients, while those fragments were all detected in the control subjects. Several different fragments around the AVPR2 locus were amplified step by step. It was revealed that a genomic fragment of 5,995-bp, which contained the entire AVPR2 gene and the last exon (exon 22) of the C1 gene, was deleted and a 3-bp (GAG) was inserted. Examination of the other family members showed that the mothers and the grandmother were carriers for this deletion. CONCLUSION: Our findings suggest that the two patients in a Chinese family suffering from congenital NDI had a 5,995-bp deletion and 3-bp (GAG) insertion at Xq28. The deletion contained the entire AVPR2 gene and exon 22 of the C1 gene
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