497 research outputs found

    Expression of wheat gibberellins 2-oxidase gene induced dwarf or semi-dwarf phenotype in rice

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    Gibberellins (GAs) are a class of plant hormones that play important roles in diverse aspects during plant growth and development. A series of GA synthesis and metabolism genes have been reported or proved to have essential functions in different plant species, while a small number of GA 2-oxidase genes have been cloned or reported in wheat. Previous studies have provided some important findings on the process of GA biosynthesis and the enzymes involved in its related pathways. These may facilitate understanding of the complicated process underlying GA synthesis and metabolism in wheat. In this study, GA 2-oxidase genes TaGA2ox1-1, TaGA2ox1-2, TaGA2ox1-3, TaGA2ox1-4, TaGA2ox1-5, and TaGA2ox1-6 were identified and further overexpressed in rice plants to investigate their functions in GA biosynthesis and signaling pathway. Results showed overexpression of GA 2-oxidase genes in rice disrupted the GA metabolic pathways and induced catalytic responses and regulated other GA biosynthesis and signaling pathway genes, which further leading to GA signaling disorders and diversity in phenotypic changes in rice plants

    Solving Solar Neutrino Puzzle via LMA MSW Conversion

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    We analyze the existing solar neutrino experiment data and show the allowed regions. The result from SNO's salt phase itself restricts quite a lot the allowed region's area. Reactor neutrinos play an important role in determining oscillation parameters. KamLAND gives decisive conclusion on the solution to the solar neutrino puzzle, in particular, the spectral distortion in the 766.3 Ty KamLAND data gives another new improvement in the constraint of solar MSW-LMA solutions. We confirm that at 99.73% C.L. the high-LMA solution is excluded.Comment: 6 eps figure

    Investigation on wear and rolling contact fatigue of wheel-rail materials under various wheel/rail hardness ratio and creepage conditions

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    The wear and rolling contact fatigue of wheel-rail materials were investigated through varying wheel/rail hardness ratios (Hw/Hr) and creepages. The results indicated that with the Hw/Hr increasing from 0.927 to 1.218, the wheel wear rate reduced significantly in the case of Hw/Hr = 1.218, the rail wear rate showed an increasing trend. Both the wheel and rail wear rates increased as the creepage enlarged. The synergistic results of Hw/Hr and creepage caused a transition of the wear and damage mechanisms on the wheel-rail steels. Besides, the fatigue damage of ER7 and CL60 wheel materials was dominated by slender multi-layer cracks, while the fatigue cracks were short and contained lots of interlayer broken materials on C-class wheel steel

    Direct Measurements of the Branching Fractions for D0Ke+νeD^0 \to K^-e^+\nu_e and D0πe+νeD^0 \to \pi^-e^+\nu_e and Determinations of the Form Factors f+K(0)f_{+}^{K}(0) and f+π(0)f^{\pi}_{+}(0)

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    The absolute branching fractions for the decays D0Ke+νeD^0 \to K^-e ^+\nu_e and D0πe+νeD^0 \to \pi^-e^+\nu_e are determined using 7584±198±3417584\pm 198 \pm 341 singly tagged Dˉ0\bar D^0 sample from the data collected around 3.773 GeV with the BES-II detector at the BEPC. In the system recoiling against the singly tagged Dˉ0\bar D^0 meson, 104.0±10.9104.0\pm 10.9 events for D0Ke+νeD^0 \to K^-e ^+\nu_e and 9.0±3.69.0 \pm 3.6 events for D0πe+νeD^0 \to \pi^-e^+\nu_e decays are observed. Those yield the absolute branching fractions to be BF(D0Ke+νe)=(3.82±0.40±0.27)BF(D^0 \to K^-e^+\nu_e)=(3.82 \pm 0.40\pm 0.27)% and BF(D0πe+νe)=(0.33±0.13±0.03)BF(D^0 \to \pi^-e^+\nu_e)=(0.33 \pm 0.13\pm 0.03)%. The vector form factors are determined to be f+K(0)=0.78±0.04±0.03|f^K_+(0)| = 0.78 \pm 0.04 \pm 0.03 and f+π(0)=0.73±0.14±0.06|f^{\pi}_+(0)| = 0.73 \pm 0.14 \pm 0.06. The ratio of the two form factors is measured to be f+π(0)/f+K(0)=0.93±0.19±0.07|f^{\pi}_+(0)/f^K_+(0)|= 0.93 \pm 0.19 \pm 0.07.Comment: 6 pages, 5 figure

    The ARGO-YBJ Experiment Progresses and Future Extension

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    Gamma ray source detection above 30TeV is an encouraging approach for finding galactic cosmic ray origins. All sky survey for gamma ray sources using wide field of view detector is essential for population accumulation for various types of sources above 100GeV. To target the goals, the ARGO-YBJ experiment has been established. Significant progresses have been made in the experiment. A large air shower detector array in an area of 1km2 is proposed to boost the sensitivity. Hybrid detection with multi-techniques will allow a good discrimination between different types of primary particles, including photons and protons, thus enable an energy spectrum measurement for individual specie. Fluorescence light detector array will extend the spectrum measurement above 100PeV where the second knee is located. An energy scale determined by balloon experiments at 10TeV will be propagated to ultra high energy cosmic ray experiments

    Search for the Lepton Flavor Violation Processes J/ψJ/\psi \to μτ\mu\tau and eτe\tau

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    The lepton flavor violation processes J/ψμτJ/\psi \to \mu\tau and eτe\tau are searched for using a sample of 5.8×107\times 10^7 J/ψJ/\psi events collected with the BESII detector. Zero and one candidate events, consistent with the estimated background, are observed in J/ψμτ,τeνˉeντJ/\psi \to \mu\tau, \tau\to e\bar\nu_e\nu_{\tau} and J/ψeτ,τμνˉμντJ/\psi\to e\tau, \tau\to\mu\bar\nu_{\mu}\nu_{\tau} decays, respectively. Upper limits on the branching ratios are determined to be Br(J/ψμτ)<2.0×106Br(J/\psi\to\mu\tau)<2.0 \times 10^{-6} and Br(J/ψeτ)<8.3×106Br(J/\psi \to e\tau) < 8.3 \times10^{-6} at the 90% confidence level (C.L.).Comment: 9 pages, 2 figure

    The σ\sigma pole in J/ψωπ+πJ/\psi \to \omega \pi^+ \pi^-

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    Using a sample of 58 million J/ψJ/\psi events recorded in the BESII detector, the decay J/ψωπ+πJ/\psi \to \omega \pi^+ \pi^- is studied. There are conspicuous ωf2(1270)\omega f_2(1270) and b1(1235)πb_1(1235)\pi signals. At low ππ\pi \pi mass, a large broad peak due to the σ\sigma is observed, and its pole position is determined to be (541±39)(541 \pm 39) - ii (252±42)(252 \pm 42) MeV from the mean of six analyses. The errors are dominated by the systematic errors.Comment: 15 pages, 6 figures, submitted to PL

    Observation of the decay \psip\rar\kstark

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    Using 14 million ψ(2S)\psi(2S) events collected with the BESII detector, branching fractions of \psip\rar\kstarkpm and \kstarknn are determined to be: \calB(\psip\rar\kstarkpm)=(2.9^{+1.3}_{-1.7}\pm0.4)\times 10^{-5} and \calB(\psip\rar\kstarknn)=(13.3^{+2.4}_{-2.7}\pm1.9)\times 10^{-5}. The results confirm the violation of the "12%" rule for these two decay channels with higher precision. A large isospin violation between the charged and neutral modes is observed.Comment: 5 pages, 3 figure

    Fabrication of CuO nanoparticle interlinked microsphere cages by solution method

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    Here we report a very simple method to convert conventional CuO powders to nanoparticle interlinked microsphere cages by solution method. CuO is dissolved into aqueous ammonia, and the solution is diluted by alcohol and dip coating onto a glass substrate. Drying at 80 °C, the nanostructures with bunchy nanoparticles of Cu(OH)2can be formed. After the substrate immerges into the solution and we vaporize the solution, hollow microspheres can be formed onto the substrate. There are three phases in the as-prepared samples, monoclinic tenorite CuO, orthorhombic Cu(OH)2, and monoclinic carbonatodiamminecopper(II) (Cu(NH3)2CO3). After annealing at 150 °C, the products convert to CuO completely. At annealing temperature above 350 °C, the hollow microspheres became nanoparticle interlinked cages

    High pTp_{T} non-photonic electron production in pp+pp collisions at s\sqrt{s} = 200 GeV

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    We present the measurement of non-photonic electron production at high transverse momentum (pT>p_T > 2.5 GeV/cc) in pp + pp collisions at s\sqrt{s} = 200 GeV using data recorded during 2005 and 2008 by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The measured cross-sections from the two runs are consistent with each other despite a large difference in photonic background levels due to different detector configurations. We compare the measured non-photonic electron cross-sections with previously published RHIC data and pQCD calculations. Using the relative contributions of B and D mesons to non-photonic electrons, we determine the integrated cross sections of electrons (e++e2\frac{e^++e^-}{2}) at 3 GeV/c<pT< c < p_T <~10 GeV/cc from bottom and charm meson decays to be dσ(Be)+(BDe)dyeye=0{d\sigma_{(B\to e)+(B\to D \to e)} \over dy_e}|_{y_e=0} = 4.0±0.5\pm0.5({\rm stat.})±1.1\pm1.1({\rm syst.}) nb and dσDedyeye=0{d\sigma_{D\to e} \over dy_e}|_{y_e=0} = 6.2±0.7\pm0.7({\rm stat.})±1.5\pm1.5({\rm syst.}) nb, respectively.Comment: 17 pages, 17 figure
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