5,946 research outputs found
Numerical Study of the Spin Hall Conductance in the Luttinger Model
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
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
Coexisting Innominate Vein Compression Syndrome and May-Thurner Syndrome
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
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 kV/cm in high dots. Eight-band 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
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 and mesons, the temperature and density
dependence of the effective hadron masses approaches more towards the Brown-Rho
scaling law, and the compression modulus is reduced from in mean
field theory to an accepted value .Comment: 5 pages, 6 figures in Revtex. Final version to be publishe
Leibniz 2-algebras and twisted Courant algebroids
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 -algebras and geometric structures behind them are exactly
-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
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
- …