165 research outputs found

    Control of emerging-market target and stock performance: Evidence in Vietnam

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    Joining the upward trend of Global Foreign direct investment and FDI in emerging economies and emerging Asian economies, FDI to Vietnam, especially M&As have increased significantly in both numbers and value of deals from 1995 to 2015. Compared with the deal triggered by a firm from Vietnam or another developing country, the deal triggered by a developed market acquirer dominates the peers in terms of return for the acquirer’s shareholder. The acquirer’s shareholder gains on their investment spent on the Vietnamese acquirer. Especially, the transfer in control of Vietnamese firms to developed-market acquirers drives the statistically significant return using the event study with the OLS market model approach

    The Hubbard model on a complete graph: Exact Analytical results

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    We derive the analytical expression of the ground state of the Hubbard model with unconstrained hopping at half filling and for arbitrary lattice sites.Comment: Email:[email protected]

    An improved study of the kappa resonance and the non-exotic ss wave πK\pi K scatterings up to s=2.1\sqrt{s}=2.1GeV of LASS data

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    We point out that the dispersion relation for the left hand cut integral presented in one of our previous paper (Nucl. Phys. {\bf A}733(2004)235) is actually free of subtraction constant, even for unequal mass elastic scatterings. A new fit to the LASS data~\cite{Aston} is performed and firm evidence for the existence of κ\kappa pole is found. The correct use of analyticity also put strong constraints on threshold parameters -- which are found to be in good agreement with those obtained from chiral theories. We also determined the pole parameters of K0(1430)K_0^*(1430) on the second sheet, and reconfirm the existence of K0(1950)K_0^*(1950) on the third sheet. We stress that the LASS data do not require them to have the twin pole structure of a typical Breit--Wigner resonance.Comment: 14 pages + 4 postscript figures; discussions largely expanded; references added; version to appear in NPA; title changed in the journa

    The Constraints of Unitary on ππ\pi\pi Scattering Dispersion Relations

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    A new dispersion relation for the partial wave ππ\pi\pi scattering SS matrix is set up. Using the dispersion relation we generalize the single channel unitarity condition, SS+=1SS^+=1, to the entire complex ss plane, which is equivalent to the generalized unitarity condition in quantum mechanics. The pole positions of the σ\sigma resonance and the f0(980)f_0(980) resonance are estimated based on the theoretical relations we obtained. The central value of the σ\sigma pole position is Mσ410M_\sigma\simeq 410MeV, Γσ550\Gamma_\sigma\simeq 550MeV, obtained after including the the constraint of the Adler zero condition.Comment: 10 pages with 4 figures, revised version to appear in Phys. Lett.

    Vibrational Properties of Nanoscale Materials: From Nanoparticles to Nanocrystalline Materials

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    The vibrational density of states (VDOS) of nanoclusters and nanocrystalline materials are derived from molecular-dynamics simulations using empirical tight-binding potentials. The results show that the VDOS inside nanoclusters can be understood as that of the corresponding bulk system compressed by the capillary pressure. At the surface of the nanoparticles the VDOS exhibits a strong enhancement at low energies and shows structures similar to that found near flat crystalline surfaces. For the nanocrystalline materials an increased VDOS is found at high and low phonon energies, in agreement with experimental findings. The individual VDOS contributions from the grain centers, grain boundaries, and internal surfaces show that, in the nanocrystalline materials, the VDOS enhancements are mainly caused by the grain-boundary contributions and that surface atoms play only a minor role. Although capillary pressures are also present inside the grains of nanocrystalline materials, their effect on the VDOS is different than in the cluster case which is probably due to the inter-grain coupling of the modes via the grain-boundaries.Comment: 10 pages, 7 figures, accepted for publication in Phys. Rev.

    The κ\kappa resonance in s wave πK\pi K scatterings

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    A new unitarization approach incorporated with chiral symmetry is established and applied to study the πK\pi K elastic scatterings. We demonstrate that the κ\kappa resonance exists, if the scattering length parameter in the I=1/2, J=0 channel does not deviate much from its value predicted by chiral perturbation theory. The mass and width of the κ\kappa resonance is found to be Mκ=594±79MeVM_\kappa=594\pm 79MeV, Γκ=724±332MeV\Gamma_\kappa=724\pm 332MeV, obtained by fitting the LASS data up to 1430MeV. Better determination to the pole parameters is possible if the chiral predictions on scattering lengths are taken into account.Comment: Minor corrections made on discussions and typos. 1 ref. added version to appear in Nuclear Physics

    The [1,2] Pad\'e Amplitudes for ππ\pi\pi Scatterings in Chiral Perturbation Theory

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    A detailed analysis to the [1,2] Pad\'e approximation to the ππ\pi\pi scattering 2--loop amplitudes in chiral perturbation theory is made.Comment: Discussions expanded and references are added, version to appear in Physics Letters

    A study of charged kappa in J/ψK±Ksππ0J/\psi \to K^{\pm} K_s \pi^{\mp} \pi^0

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    Based on 58×10658 \times 10^6 J/ψJ/\psi events collected by BESII, the decay J/ψK±Ksππ0J/\psi \to K^{\pm} K_s \pi^{\mp} \pi^0 is studied. In the invariant mass spectrum recoiling against the charged K(892)±K^*(892)^{\pm}, the charged κ\kappa particle is found as a low mass enhancement. If a Breit-Wigner function of constant width is used to parameterize the kappa, its pole locates at (849±7714+18)i(256±4022+46)(849 \pm 77 ^{+18}_{-14}) -i (256 \pm 40 ^{+46}_{-22}) MeV/c2c^2. Also in this channel, the decay J/ψK(892)+K(892)J/\psi \to K^*(892)^+ K^*(892)^- is observed for the first time. Its branching ratio is (1.00±0.190.32+0.11)×103(1.00 \pm 0.19 ^{+0.11}_{-0.32}) \times 10^{-3}.Comment: 14 pages, 4 figure

    Osteoprotegerin: A Novel Secreted Protein Involved in the Regulation of Bone Density

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    AbstractA novel secreted glycoprotein that regulates bone resorption has been identified. The protein, termed Osteoprotegerin (OPG), is a novel member of the TNF receptor superfamily. In vivo, hepatic expression of OPG in transgenic mice results in a profound yet nonlethal osteopetrosis, coincident with a decrease in later stages of osteoclast differentiation. These same effects are observed upon administration of recombinant OPG into normal mice. In vitro, osteoclast differentiation from precursor cells is blocked in a dose-dependent manner by recombinant OPG. Furthermore, OPG blocks ovariectomy-associated bone loss in rats. These data show that OPG can act as a soluble factor in the regulation of bone mass and imply a utility for OPG in the treatment of osteoporosis associated with increased osteoclast activity
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