486 research outputs found

    Radiative corrections to the decay H+W+A0H^+ \to W^+ A^0

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    Full one-loop electroweak corrections to the on-shell decay H+W+A0H^+ \to W^+A^0 are computed in the framework of models with two Higgs doublets (THDM). Such a decay may be dominant for H±H^{\pm} over a wide range of parameter space relevant at present and future colliders. We show that the corrections may approach 40% and in particular are sensitive to λ5\lambda_5, which parametrizes the discrete symmetry breaking term. We suggest that a measurement of the branching ratio of H+W+A0H^+ \to W^+A^0 may offer a possibility of measuring the magnitude of λ5\lambda_5.Comment: 27 pages, LaTex, 6 figures, one figure added, appendix shortened. To be published in Eur. Phys. Jour.

    Spatial Graphs with Local Knots

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    It is shown that for any locally knotted edge of a 3-connected graph in S3S^3, there is a ball that contains all of the local knots of that edge and is unique up to an isotopy setwise fixing the graph. This result is applied to the study of topological symmetry groups of graphs embedded in S3S^3.Comment: 20 pages, 3 figures; in v. 2 the proof of Theorem 1 has been clarified, and other minor revisions have been mad

    Note on tree-level unitarity in the General Two Higgs Doublet Model

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    Tree-level unitarity constraints on the masses of the Higgs bosons in the general Two Higgs Doublet Model (THDM) are studied. We first consider the case where the Higgs potential is invariant under a discrete symmetry transformation, and derive strong constraints on the mass of the lightest CP-even Higgs boson (MhM_h) as a function of tanβ\tan\beta. We then show that the inclusion of the discrete symmetry breaking term weakens the mass bounds considerably. It is suggested that a measurement of MhM_h and tanβ\tan\beta may enable discrimination between the two Higgs potentials.Comment: 10 pages, LaTeX, 2 PostScript figure

    On the validity of the Wigner-Seitz approximation in neutron star crust

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    The inner crust of neutron stars formed of nuclear clusters immersed in a neutron sea has been widely studied in the framework of the Wigner-Seitz approximation since the seminal work of Negele and Vautherin. In this article, the validity of this approximation is discussed in the framework of the band theory of solids. For a typical cell of 200^{200}Zr, present in the external layers of the inner crust, it is shown that the ground state properties of the neutron gas are rather well reproduced by the Wigner-Seitz approximation, while its dynamical properties depend on the energy scale of the process of interest or on the temperature. It is concluded that the Wigner-Seitz approximation is well suited for describing the inner crust of young neutron stars and the collapsing core of massive stars during supernovae explosions. However the band theory is required for low temperature fluid dynamics.Comment: 7 pages, with figures - PTH, version

    Alcohol Policies and Alcoholic Cirrhosis Mortality in the United States

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    Introduction Stronger alcohol policies predict decreased alcohol consumption and binge drinking in the United States. We examined the relation- ship between the strength of states’ alcohol policies and alcoholic cirrhosis mortality rates. Methods We used the Alcohol Policy Scale (APS), a validated assessment of policies of the 50 US states and Washington DC, to quantify the efficacy and implementation of 29 policies. State APS scores (the- oretical range, 0–100) for each year from 1999 through 2008 were compared with age-adjusted alcoholic cirrhosis death rates that oc- curred 3 years later. We used Poisson regression accounting for state-level clustering and adjusting for race/ethnicity, college edu- cation, insurance status, household income, religiosity, policing rates, and urbanization. Results Age-adjusted alcoholic cirrhosis mortality rates varied signific- antly across states; they were highest among males, among resid- ents in states in the West census region, and in states with a high proportion of American Indians/Alaska Natives (AI/ANs). Higher APS scores were associated with lower mortality rates among fe- males (adjusted incidence rate ratio [IRR], 0.91 per 10-point in- crease in APS score; 95% confidence interval [95% CI], 0.84–0.99) but not among males (adjusted IRR, 0.97; 95% CI, 0.90–1.04). Among non-AI/AN decedents, higher APS scores were also associated with lower alcoholic cirrhosis mortality rates among both sexes combined (adjusted IRR, 0.89; 95% CI, 0.82–0.97). Policies were more strongly associated with lower mortality rates among those living in the Northeast and West census regions than in other regions. Conclusions Stronger alcohol policy environments are associated with lower al- coholic cirrhosis mortality rates. Future studies should identify un- derlying reasons for racial/ethnic and regional differences in this relationship

    The effect of magnesium on bioactivity, rheology and biology behaviors of injectable bioactive glass-gelatin-3-glycidyloxypropyl trimethoxysilane nanocomposite-paste for small bone defects repair

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    Injectable bioactive glass-based pastes represent promising biomaterials to fill small bone defects thus improving and speed up the self-healing process. Accordingly, injectable nanocomposite pastes based on bioactive glass-gelatin-3-glycidyloxypropyl trimethoxysilane (GPTMS) were here synthesized via two different glasses 64SiO2. 27CaO. 4MgO. 5P2O5 (mol.%) and 64SiO2.31CaO. 5P2O5 (mol.%). In particular, the effects of MgO on bioactivity, rheology, injectability, disintegration resistance, compressive strength and cellular behaviors were investigated. The results showed that the disintegration resistance and compressive strength of the composite were improved by the replacement of MgO; thus, leading to an increase in the amount of storage modulus (G′) from 26800 to 43400 Pa, equal to an increase in the viscosity of the paste from 136 × 103 to 219 × 103 Pa s. Since the release rate of ions became more controllable, the formation of calcite was decreased after immersion of the Mg bearing samples in the SBF solution. Specimens’ cytocompatibility was firstly verified towards human osteoblasts by metabolic assay as well as visually confirmed by the fluorescent live/dead staining; finally, the ability of human fibroblasts to penetrate within the pores of 3D composites was verified by a migration assay simulating the devices repopulation upon injection in the injured site

    Bioarchaeology-related studies in the Arabian Gulf: potentialities and shortcomings

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    Archaeological studies provide a powerful tool to understand the prehistoric societies, especially when combined to cutting-edge morphological and molecular anthropological analyses, allowing reconstructing past population dynamics, admixture events, and socio-cultural changes. Despite the advances achieved in the last decades by archaeological studies worldwide, several regions of the World have been spared from this scientific improvement due to various reasons. The Arabian Gulf represents a unique ground to investigate, being the passageway for human migrations and one of the hypothesized areas in which Neanderthal introgression occurred. A number of archaeological sites are currently present in the Arabian Gulf and have witnessed the antiquity and the intensiveness of the human settlements in the region. Nevertheless, the archaeological and anthropological investigation in the Gulf is still in its infancy. Data collected through archaeological studies in the area have the potential to help answering adamant questions of human history from the beginning of the structuring of genetic diversity in human species to the Neolithisation process. This review aims at providing an overview of the archaeological studies in the Arabian Gulf with special focus to Qatar, highlighting potentialities and shortcomings

    Enterotoxin-producing Escherichia coli O169:H41, United States

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    From 1996 to 2003, 16 outbreaks of enterotoxigenic Escherichia coli (ETEC) infections in the United States and on cruise ships were confirmed. E. coli serotype O169:H41 was identified in 10 outbreaks and was the only serotype in 6. This serotype was identified in 1 of 21 confirmed ETEC outbreaks before 1996
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