5,634 research outputs found

    New cosmological constraints with extended-Baryon Oscillation Spectroscopic Survey DR14 quasar sample

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    We update the constraints on the cosmological parameters by adopting the Planck data released in 2015 and Baryon Acoustic Oscillation (BAO) measurements including the new DR14 quasar sample measurement at redshift z=1.52z=1.52, and we conclude that the based six-parameter Ξ›\LambdaCDM model is preferred. Exploring some extensions to the Ξ›\LambdaCDM models, we find that the equation of state of dark energy reads w=βˆ’1.036Β±0.056w=-1.036\pm 0.056 in the wwCDM model, the effective relativistic degrees of freedom in the Universe is Neff=3.09βˆ’0.20+0.18N_\text{eff}=3.09_{-0.20}^{+0.18} in the Neff+Ξ›N_\text{eff}+\LambdaCDM model and the spatial curvature parameter is Ξ©k=(1.8Β±1.9)Γ—10βˆ’3\Omega_k=(1.8\pm1.9)\times 10^{-3} in the Ξ©k+Ξ›\Omega_k+\LambdaCDM model at 68%68\% confidence level (C.L.), and the 95%95\% C.L. upper bounds on the sum of three active neutrinos masses are βˆ‘mΞ½<0.16\sum m_\nu<0.16 eV for the normal hierarchy (NH) and βˆ‘mΞ½<0.19\sum m_\nu<0.19 eV for the inverted hierarchy (IH) with Δχ2≑χNH2βˆ’Ο‡IH2=βˆ’1.25\Delta\chi^2\equiv \chi^2_\text{NH}-\chi^2_\text{IH}=-1.25.Comment: 9 pages, 5 figures, 4 table

    Complete phase diagram and topological properties of interacting bosons in one-dimensional superlattices

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    The interacting bosons in one-dimensional inversion-symmetric superlattices are investigated from the topological aspect. The complete phase diagram is obtained by an atomic-limit analysis and quantum Monte Carlo simulations and comprises three kinds of phases: superfluid, persisted charge-density-wave and Mott insulators, and emergent insulators in the presence of nearest-neighbor hoppings. We find that all emergent insulators are topological, which are characterized by the Berry phase Ο€\pi and a pair of degenerate in-gap boundary states. The mechanism of the topological bosonic insulators is qualitatively discussed and the ones with higher fillings can be understood as a 13\frac{1}{3}-filling topological phase on a background of trivial charge-density-wave or Mott insulators.Comment: 6 pages, 8 figures. Accelpted for publication in Phys. Rev.

    Management of duodenal trauma

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    AbstractDuodenal trauma is uncommon but nowadays seen more and more frequently due to the increased automobile accidents and violent events. The management of duodenal trauma can be complicated, especially when massive injury to the pancreatic-duodenal-biliary complex occurs simultaneously. Even the patients receive surgeries in time, multiple postoperative complications and high mortality are common. To know and manage duodenal trauma better, we searched the recent related literature in PubMed by the keywords of duodenal trauma, therapy, diagnosis and abdomen. It shows that because the diagnosis and management are complicated and the mortality is high, duodenal trauma should be treated in time and tactfully. And application of new technology can help improve the management. In this review, we discussed the incidence, diagnosis, management, and complications as well as mortality of duodenal trauma

    Spin singlet pairing in the superconducting state of NaxCoO2\cdot1.3H2O: evidence from a ^{59}Co Knight shift in a single crystal

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    We report a ^{59}Co Knight shift measurement in a single crystal of the cobalt oxide superconductor Na_{x}CoO_2\cdot1.3H_2O (T_c=4.25 K). We find that the shift due to the spin susceptibility, K^s, is substantially large and anisotropic, with the spin shift along the a-axis K^s_a being two times that along the c-axis K^s_c. The shift decreases with decreasing temperature (T) down to T\sim100 K, then becomes a constant until superconductivity sets in. Both K^s_a and K^s_c decrease below T_c. Our results indicate unambiguously that the electron pairing in the superconducting state is in the spin singlet form.Comment: 4 pages, 5 figure
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