3,850 research outputs found

    Cannot Live without Facebook? An Expectation Confirmation Model with the Moderating Effects of Narcissism

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    Facebook provides an ideal channel for people to admire their own performance. People tend to show off themselves to others and confirming their feedback on Facebook. With behavior on Facebook, narcissism is now highlighted by many researchers. Hence, based on the expectation confirmation theory (ECT), our study looks into continuance Facebook usage behaviors. It explores the relationship between perceived feedback, confirmation, satisfaction, and continuance intentions, and most important of all, it examines the moderating effects of narcissistic traits on these relationships. Data are collected from 420 valid respondents through self-administered questionnaires. Results revealed that: (1) Continuance Facebook behavior intention is jointly influenced by perceived feedback and satisfaction, which in turn is determined by confirmation. Then, confirmation is influenced by perceived feedback; (2) Narcissism has the moderating effect on the relationships between feedback and confirmation as well as confirmation and satisfaction. Finally, interpretations and implication of these findings are discussed

    Anomalous electronic Raman scattering in Na_xCoO_2 H_2O

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    Raman scattering experiments on Na_{x}CoO_2 yH_2O single crystals show a broad electronic continuum with a pronounced peak around 100 cm-1 and a cutoff at approximately 560 cm-1over a wide range of doping levels. The electronic Raman spectra in superconducting and non-superconducting samples are similar at room temperature, but evolve in markedly different ways with decreasing temperature. For superconducting samples, the low-energy spectral weight is depleted upon cooling below T* sim 150K, indicating a opening of a pseudogap that is not present in non-superconducting materials. Weak additional phonon modes observed below T* suggest that the pseudogap is associated with charge ordering.Comment: 5 pages, 4 figures, for further information see www.peter-lemmens.d

    The Numerical Solution of Scalar Field for Nariai Case in 5D Ricci-flat SdS Black String Space with Polynomial Approximation

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    As one exact candidate of the higher dimensional black hole, the 5D Ricci-flat Schwarzschild-de Sitter black string space presents something interesting. In this paper, we give a numerical solution to the real scalar field around the Nariai black hole by the polynomial approximation. Unlike the previous tangent approximation, this fitting function makes a perfect match in the leading intermediate region and gives a good description near both the event and the cosmological horizons. We can read from our results that the wave is close to a harmonic one with the tortoise coordinate. Furthermore, with the actual radial coordinate the waves pile up almost equally near the both horizons.Comment: 8 pages, 4 figure

    New Analytical Formula for Supercritical Accretion Flows

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    We examine a new family of global analytic solutions for optically thick accretion disks, which includes the supercritical accretion regime. We found that the ratio of the advection cooling rate, QadvQ_{\rm adv}, to the viscous heating rate, QvisQ_{\rm vis}, i.e., f=Qadv/Qvisf=Q_{\rm adv}/Q_{\rm vis}, can be represented by an analytical form dependent on the radius and the mass accretion rate. The new analytic solutions can be characterized by the photon-trapping radius, \rtrap, inside which the accretion time is less than the photon diffusion time in the vertical direction; the nature of the solutions changes significantly as this radius is crossed. Inside the trapping radius, ff approaches fr0f \propto r^0, which corresponds to the advection-dominated limit (f1f \sim 1), whereas outside the trapping radius, the radial dependence of ff changes to fr2f \propto r^{-2}, which corresponds to the radiative-cooling-dominated limit. The analytical formula for ff derived here smoothly connects these two regimes. The set of new analytic solutions reproduces well the global disk structure obtained by numerical integration over a wide range of mass accretion rates, including the supercritical accretion regime. In particular, the effective temperature profiles for our new solutions are in good agreement with those obtained from numerical solutions. Therefore, the new solutions will provide a useful tool not only for evaluating the observational properties of accretion flows, but also for investigating the mass evolution of black holes in the presence of supercritical accretion flows.Comment: 14 pages, 7 figures, accepted for publication in the Astrophysical Journa

    Fermion Pairing Dynamics in the Relativistic Scalar Plasma

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    Using many-body techniques we obtain the time-dependent Gaussian approximation for interacting fermion-scalar field models. This method is applied to an uniform system of relativistic spin-1/2 fermion field coupled, through a Yukawa term, to a scalar field in 3+1 dimensions, the so-called quantum scalar plasma model. The renormalization for the resulting Gaussian mean-field equations, both static and dynamical, are examined and initial conditions discussed. We also investigate solutions for the gap equation and show that the energy density has a single minimum.Comment: 21 pages, latex, 4 postscript figures, new sections, some literary changes, notation corrections, accepted for publication in Phys. Rev

    Weighted ergodic theorems for Banach-Kantorovich lattice Lp(^,μ^)L_{p}(\hat{\nabla},\hat{\mu})

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    In the present paper we prove weighted ergodic theorems and multiparameter weighted ergodic theorems for positive contractions acting on Lp(^,μ^)L_p(\hat{\nabla},\hat{\mu}). Our main tool is the use of methods of measurable bundles of Banach-Kantorovich lattices.Comment: 11 page

    Stent implantation for a totally occluded right coronary artery in a six-year-old boy after Kawasaki disease: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Coronary stenting has previously been considered to be less feasible in children under 12 years old due to the limitation of vascular access. We report the case of a six-year-old boy who successfully underwent stent implantation for his totally occluded right coronary artery.</p> <p>Case presentation</p> <p>A Taiwanese boy aged six years and nine months old was found to have giant aneurysms after an acute episode of Kawasaki disease. An angiography revealed that his middle right coronary artery was totally occluded. A 0.014-inch guidewire was advanced to cross the totally occluded site. After pre-dilating the middle portion of his right coronary artery with a 1.5 mm balloon, stenting of his right coronary artery was accomplished using a 2.5 × 28 mm and a 2.5 × 18 mm bare metal stent. A final angiography demonstrated no residual stenosis or dissection.</p> <p>Conclusion</p> <p>Coronary stenting could be a therapeutic option for children as young as six years old. Close follow-up is mandatory because the long-term outcome is still unclear, especially in a small child.</p

    The Minimum Stellar Mass in Early Galaxies

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    The conditions for the fragmentation of the baryonic component during merging of dark matter halos in the early Universe are studied. We assume that the baryonic component undergoes a shock compression. The characteristic masses of protostellar molecular clouds and the minimum masses of protostars formed in these clouds decrease with increasing halo mass. This may indicate that the initial stellar mass function in more massive galaxies was shifted towards lower masses during the initial stages of their formation. This would result in an increase of the number of stars per unit halo mass, i.e., the efficiency of star formation.Comment: 18 pages, 7 figure
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