5,831 research outputs found

    Numerical Study of the Spin Hall Conductance in the Luttinger Model

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    We present first numerical studies of the disorder effect on the recently proposed intrinsic spin Hall conductance in a three dimensional (3D) lattice Luttinger model. The results show that the spin Hall conductance remains finite in a wide range of disorder strength, with large fluctuations. The disorder-configuration-averaged spin Hall conductance monotonically decreases with the increase of disorder strength and vanishes before the Anderson localization takes place. The finite-size effect is also discussed.Comment: 4 pages, 4 figures; the final version appearing in PR

    Modeling the WHO-EPI Vaccine Supply Chain in Low and Middle Income Countries

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    The enormous economic impact of diseases has drawn global attention and controlling diseases through a vaccination program is one of the highest priorities in healthcare decision making. However, successful implementation of vaccination programs must also consider distribution network design and logistical feasibility. In this research we address this issue via three broad contributions. First, we develop a generic mathematical programming model of the WHO-EPI vaccine distribution network in low and middle countries, and adapt the model to answer actual vaccine logistics questions such as assessing the feasibility of new vaccine introductions, changing the distribution network design, and changing the vial size of an existing vaccine using the West African country of Niger to illustrate this. Second, we explore integrating vaccine distribution decisions with immunization policies by developing a framework for linking the vaccine supply chain model with a disease propagation model. The framework is used to assess measles interventions in Niger in order to help policy makers decide on an appropriate vaccination policy. Third, we address the significant challenge of increasing the clinic visit rate, especially in areas with limited health care resources and high-risk populations. To do this we explore the application of passive cold devices for vaccine delivery at remote vaccination sites. Such mobile devices are easy to deploy at locations that are off the electricity grid or have an unstable energy supply, and they can also be used to support outreach vaccinations to families in rural areas. We develop a computational model to evaluate the cost effectiveness of different device designs for vaccine delivery in real world distribution networks. We also conduct sensitivity analysis to determine which design is most robust with respect to fluctuations in cost performance

    Three-Dimensional Digital Colour Camera

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    Coexisting Innominate Vein Compression Syndrome and May-Thurner Syndrome

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    AbstractInnominate vein compression syndrome and May-Thurner syndrome (also called iliac vein compression syndrome) are venous compression syndromes caused by normal anatomic structures. Here, we present a case in which these two conditions were found in the same patient using multidetector row computed tomography. This case is significant for two reasons: (1) it is, to the best of our knowledge, the first case study in the literature to report coexisting innominate vein compression syndrome and May-Thurner syndrome; and (2) it shows that multidetector row computed tomography has powerful diagnostic ability for venous diseases

    Absence of correlation between built-in electric dipole moment and quantum Stark effect in InAs/GaAs self-assembled quantum dots

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    We report significant deviations from the usual quadratic dependence of the ground state interband transition energy on applied electric fields in InAs/GaAs self-assembled quantum dots. In particular, we show that conventional second-order perturbation theory fails to correctly describe the Stark shift for electric field below F=10F = 10 kV/cm in high dots. Eight-band kp{\bf k}\cdot{\bf p} calculations demonstrate this effect is predominantly due to the three-dimensional strain field distribution which for various dot shapes and stoichiometric compositions drastically affects the hole ground state. Our conclusions are supported by two independent experiments.Comment: 4 pages, 4 figure

    In-medium meson effects on the equation of state of hot and dense nuclear matter

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    The influence of the in-medium mesons on the effective nucleon mass and in turn on the equation of state of hot/dense nuclear matter is discussed in the Walecka model. Due to the self-consistent treatment of couplings between nucleons and σ\sigma and ω\omega mesons, the temperature and density dependence of the effective hadron masses approaches more towards the Brown-Rho scaling law, and the compression modulus KK is reduced from 550MeV550 MeV in mean field theory to an accepted value 318.2MeV318.2 MeV.Comment: 5 pages, 6 figures in Revtex. Final version to be publishe

    Leibniz 2-algebras and twisted Courant algebroids

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    In this paper, we give the categorification of Leibniz algebras, which is equivalent to 2-term sh Leibniz algebras. They reveal the algebraic structure of omni-Lie 2-algebras introduced in \cite{omniLie2} as well as twisted Courant algebroids by closed 4-forms introduced in \cite{4form}. We also prove that Dirac structures of twisted Courant algebroids give rise to 2-term LL_\infty-algebras and geometric structures behind them are exactly HH-twisted Lie algebroids introduced in \cite{Grutzmann}.Comment: 22 pages, to appear in Comm. Algebr

    The Antiinfective Effects of Velvet Antler of Formosan Sambar Deer (Cervus unicolor swinhoei) on Staphylococcus aureus-Infected Mice

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    We assayed the effects of velvet antler (VA) of Formosan sambar deer (Cervus unicolor swinhoei) and its extracts on the anti-infective activity against pathogenic Staphylococcus aureus in vitro and in vivo in this study. In vitro data indicated that the VA extracts stimulated the proliferation of resting splenocytes and macrophages in a dose-dependent manner up to the highest concentration used (150 μg mL−1). The production of proinflammatory cytokines (TNF-α, IL-6, IL-12) by lipoteichoic acid was significantly suppressed after being cocultured with the VA extracts in a dose-dependent manner. Animal test in S. aureus-infected mice demonstrated that the numbers of bacteria determined in the kidneys and peritoneal lavage fluid of S. aureus-infected mice were significantly higher than those found in the same organs of mice pretreated with the VA samples. Moreover, the highly enhanced phagocytic activity of macrophages was further verified after in vitro treatment with the VA samples. The protective mechanisms of the VA samples might include an immune enhancer and an inflammatory cytokine suppressor
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