2,607 research outputs found

    Bottom Baryons

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    Recently CDF and D0 collaborations observed several bottom baryons. In this work we perform a systematic study of the masses of bottom baryons up to 1/mQ1/m_Q in the framework of heavy quark effective field theory (HQET) using the QCD sum rule approach. The extracted chromo-magnetic splitting between the bottom baryon heavy doublet agrees well with the experimental data.Comment: 8 pages, 5 figures, 3 tables. More discussions and references adde

    A review of the open charm and open bottom systems

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    Since the discovery of the first charmed meson in 1976, many open-charm and open-bottom hadrons were observed. In 2003 two narrow charm-strange states Ds0(2317)D_{s0}^*(2317) and Ds1(2460)D_{s1}(2460) were discovered by the BaBar and CLEO Collaborations, respectively. After that, more excited heavy hadrons were reported. In this work, we review the experimental and theoretical progress in this field.Comment: Review accepted by Reports on Progress in Physics, 161 pages, 53 figures, 23 tables, more references added and review on heavy baryons adde

    Clinical study of retinal detachment associated with choroidal detachment

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    AIM: To analyze the clinical characteristics of retinal detachment associated with choroidal detachment and to evaluate the surgical techniques, the efficacy and operation time for treatment.<p>METHODS: We reviewed and analyzed the operative effects of vitreoretinal surgeries in 45 patients(45 eyes)with retinal and choroidal detachment in our hospital from January, 2010 to January, 2012. In these 45 patients, there were 38 patients of rhegmatogenous retinal detachment associated with choroidal detachment, 7 patients of retinal redetachment associated with choroidal detachment. The surgical techniques include scleral encircling operation, epichoroidal space drainage by sclerocentesis intraocular photocoagulation, gas-fluid exchange, perfluoropropane(C<sub>3</sub>F<sub>8</sub>)or silicone oil intraocular tamponade and vitreoretinal surgery.<p>RESULTS: The drainage of the suprachoroidal space liquid and blood was successful in 45 eyes. Silicone oil tamponade was performed for 39 eyes and C<sub>3</sub>F<sub>8</sub> tamponade for 6 eyes. Retinas and choroids were all reattached and retinal holes were closed. Visual acuities were improved, ≥0.1 in 23 eyes.<p>CONCLUSION: The vitreoretinal surgery and external drainage by sclerocentesis and scleral encircling operation is an effective operating method for rhegmatogenous retinal detachment associated with choroidal detachment

    Diaqua­bis(5-carb­oxy-2-propyl-1H-imidazole-4-carboxyl­ato-κ2 N 3,O 4)magnesium(II) 3.5-hydrate

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    In the title complex, [Mg(C8H9N2O4)2(H2O)2]·3.5H2O, the MgII atom is six-coordinated by two N,O-bidentate 5-carb­oxy-2-propyl-1H-imidazole-4-carboxyl­ate ligands and two water mol­ecules, forming a distorted octa­hedral environment. The complex mol­ecules are linked into a three-dimensional network by N—H⋯O and O—H⋯O hydrogen-bonding inter­actions. The propyl groups are disordered over two sites, with site occupancies of 0.755 (7):0.245 (7) and 0.556 (13):0.444 (13)

    Latest data constraint of some parameterized dark energy models

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    Using various latest cosmological datasets including Type-Ia supernovae, cosmic microwave background radiation, baryon acoustic oscillations, and estimations of the Hubble parameter, we test some dark energy models with parameterized equations of state and try to distinguish or select observation-preferred models. We obtain the best fitting results of the six models and calculate their values of the Akaike Information Criteria and Bayes Information Criterion. And we can distinguish these dark energy models from each other by using these two information criterions. However, the Λ\Lambda CDM model remains the best fit model. Furthermore, we perform geometric diagnostics including statefinder and Om diagnostics to understand the geometric behaviour of the dark energy models. We find that the six DE models can be distinguished from each other and from Λ\LambdaCDM, Chaplygin gas, quintessence models after the statefinder and Om diagnostics were performed. Finally, we consider the growth factor of the dark energy models with comparison to Λ\Lambda CDM model. Still, we find the models can be distinguished from each other and from Λ\Lambda CDM model through the growth factor approximation.Comment: 23 pages, 6 figures, to be published in CP

    Determining the Toll and Capacity of a Highway to Be Constructed in Parallel with Subway

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    This paper considers the problem of toll and capacity choice of a new highway with a bottleneck added onto an existing transit network under four ownership/tolling regimes: public fine toll, public flat toll, private fine toll, and private flat toll. Whenever fine toll and flat toll are imposed, in a competitive highway/transit network with constant returns to scale in road construction, an optimally designed and priced privately owned highway would produce positive net benefit justly equal to the total markup with respect to all autocommuters, whereas an optimally designed and priced publicly owned highway would lead to a deficit; that is, the toll revenues are insufficient to cover its all costs. The economic conditions to invest a new road are investigated under different ownership/tolling regimes
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