778 research outputs found

    Decay Constants of Pseudoscalar DD-mesons in Lattice QCD with Domain-Wall Fermion

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    We present the first study of the masses and decay constants of the pseudoscalar D D mesons in two flavors lattice QCD with domain-wall fermion. The gauge ensembles are generated on the 243×4824^3 \times 48 lattice with the extent Ns=16 N_s = 16 in the fifth dimension, and the plaquette gauge action at β=6.10 \beta = 6.10 , for three sea-quark masses with corresponding pion masses in the range 260−475260-475 MeV. We compute the point-to-point quark propagators, and measure the time-correlation functions of the pseudoscalar and vector mesons. The inverse lattice spacing is determined by the Wilson flow, while the strange and the charm quark masses by the masses of the vector mesons ϕ(1020) \phi(1020) and J/ψ(3097) J/\psi(3097) respectively. Using heavy meson chiral perturbation theory (HMChPT) to extrapolate to the physical pion mass, we obtain fD=202.3(2.2)(2.6) f_D = 202.3(2.2)(2.6) MeV and fDs=258.7(1.1)(2.9) f_{D_s} = 258.7(1.1)(2.9) MeV.Comment: 15 pages, 3 figures. v2: the statistics of ensemble (A) with m_sea = 0.005 has been increased, more details on the systematic error, to appear in Phys. Lett.

    Determination of Nucleopolyhedrovirus’ Taxonomic Position

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    To date , over 78 genomes of nucleopolyhedroviruses (NPVs) have been sequenced and deposited in NCBI. How to define a new virus from the infected larvae in the field is usually the first question. Two NPV strains, which were isolated from casuarina moth (L. xylina) and golden birdwing larvae (Troides aeacus), respectively, displayed the same question. Due to the identity of polyhedrin (polh) sequences of these two isolates to that of Lymantria dispar MNPV and Bombyx mori NPV, they are named LdMNPV-like virus and TraeNPV, provisionally. To further clarify the relationships of LdMNPV-like virus and TraeNPV to closely related NPVs, Kimura 2-parameter (K-2-P) analysis was performed. Apparently, the results of K-2-P analysis that showed LdMNPV-like virus is an LdMNPV isolate, while TraeNPV had an ambiguous relationship to BmNPV. Otherwise, MaviNPV, which is a mini-AcMNPV, also exhibited a different story by K-2-P analysis. Since K-2-P analysis could not cover all species determination issues, therefore, TraeNPV needs to be sequenced for defining its taxonomic position. For this purpose, different genomic sequencing technologies and bioinformatic analysis approaches will be discussed. We anticipated that these applications will help to exam nucleotide information of unknown species and give an insight and facilitate to this issue

    Basal Cell Carcinoma of the Head and Neck Region in Ethnic Chinese

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    Objectives. This study aims to report our experience in the management of HNBCC in ethnic Chinese over a 10-year period. Methods. A retrospective review of all ethnic Chinese patients with HNBCC treated in a tertiary centre from 1999 to 2009. Results. From 1999 to 2009, 225 patients underwent surgical excision for HNBCC. Majority were elderly female patients. Commonest presentation was a pigmented (76.2%) ulcer (64.8%) over the nose (31.6%). Median skin margin taken on tumour excision was 2.0 mm; primary skin closure was achieved in 51.8%. Postresection skin margin was clear in 75.4%. Of those with inadequate skin margins, 56.7% opted for further treatment, 43.4% for observation. Recurrence rates were 2.6% and 13.8%, respectively (P = 0.106). Overall recurrence rate was 5.5%. Conclusions. HNBCC commonly presented as pigmented ulcers over the nose of elderly female patients in our locality. Adequate tumour excision ± reconstruction offered the best chance of cure. Reexcision of those with inadequate skin margins improved local tumour control

    The atypical Gaoligong orocline: Its geodynamic origin and evolution

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    Various orocline systems around the India–Eurasia collision zone have long been recognized and studied. Different portions of the India–Eurasia boundaries represent various scales and models of orocline-forming processes, such as the Baluchistan orocline formed by multiple deformation events and the Himalayan orocline formed by a mixture of complex structural mechanisms. The curvature from the eastern Himalayan syntaxis through east Burma to west Yunnan showed a unique convex curvature toward the mantle wedge. This is different from the concave Baluchistan orocline and the Himalayan orocline. The unique geometry of the Gaoligong orocline shows an N-S trend for the northern section and a NE-SW trend for the southern section. This curvature also marks the boundary between the Tengchong and Baoshan blocks along the Santaishan suture in western Yunnan, China. Our structural reconstruction identified five deformation events: 1) D1 is km-scale upright folding, which only affected the Neoproterozoic meta-sedimentary unit, 2) D2 recumbent folding, which only developed in the southern section of the Gaoligong orocline, 3) D3 large-scale gently westward-inclined thrust folding, 4) D4 right-lateral shear belt, and 5) the D5 normal faults. Since the D3 structure is the earliest event that shows penetrative foliation development along the orocline, we consider D1 and D2 as pre-orocline-forming events. The geometry of the Gaoligong orocline is controlled by the distribution of the Ordovician basement between the Tengchong and Baoshan blocks. Both north and south sections experienced the same structural evolution since D3 (a fault-propagation fold system occurred between 40 Ma and 28 Ma), D4 (steep right-lateral shear belt occurred between 28 Ma and 15 Ma), and D5 (normal faults after 15 Ma). The curvature first developed as a shovel-like top-to-the-NE thrust plane (S3) that formed under amphibolite-facies conditions between 40 Ma and 28 Ma. The following deformation events (D4 and D5) show orocline parallel foliation development under lower metamorphic conditions, indicating that the curvature of the Gaoligong orocline is not generated by additional rotation along multiple deformation events. However, due to the lack of orocline parallel foliation development for S3, and the lack of a proper position of the indenter, the Gaoligong orocline cannot be classified as a primary orocline nor a rotational orocline. The curved geometry is an interference pattern of topography relief to the shovel-like thrust plane that developed during D3. Our new reconstructed structural evolution concludes that the Gaoligong orocline is an “atypical” orocline
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