10,007 research outputs found

    On the D0D^0 -- DsD_s lifetime difference and τ7π+ντ\tau\to 7\pi + \nu_\tau decays

    Full text link
    In this paper we discuss some aspects of inclusive decays of charmed mesons and also decays of the τ\tau lepton into ντ+7π\nu_\tau + 7\pi. We find that phase space effects are likely to explain the observed lifetime ratio τ(Ds+)/τ(D0)\tau(D_s^+) / \tau(D^0) = 1.17. In particular one need not appeal to a large annihilation contribution in the inclusive D0D^0 decay which, being absent in Ds+D_s^+ decays could also contribute to the enhanced D0D^0 decay rate relative to that of the Ds+D_s^+. Examining a separate problem, we find that the rate for τντ+7π\tau\to \nu_\tau + 7\pi is almost completely dominated by the tiny phase space for the final eight particle state. Using an effective chiral Lagrangian to estimate the matrix element yields a branching ratio into the channel of interest far smaller than the present upper bound.Comment: No figure

    Characterizing cognitive deficits and dementia in an aging urban population in India.

    Get PDF
    Rapid rise in the population of older adults in India will lead to the need for increased health care services related to diagnosis, management, and long-term care for those with dementia and cognitive impairment. A direct approach for service provision through memory clinics can be an effective, successful, and sustaining means of delivering specialized health care services. We have established a memory clinic in Mumbai, India by employing the diverse clinical skills available in Indian academic institutions, diagnostic and research expertise of clinicians and psychologists, and the support of the U.S. National Institutes of Health. Our project involved recruitment of patients, clinical and neuropsychological assessment, and standardized diagnostic procedures, demonstrating the feasibility of using research methods to develop a memory clinic. In this paper, we describe the development of a community-based memory clinic in urban India, including linguistic and cultural factors and present detailed results, including diagnostic characterization, on 194 subjects with various stages of cognitive deficits. Our findings support the feasibility of developing a memory clinic in a public hospital and successful use of research diagnostic criteria to categorize cognitive deficits observed in this population, which may be used to inform the development of other such clinics

    Hierarchically Porous Gd3+-Doped CeO2 Nanostructures for the Remarkable Enhancement of Optical and Magnetic Properties

    Get PDF
    Rare earth ion-doped CeO2 has attracted more and more attention because of its special electrical, optical, magnetic, or catalytic properties. In this paper, a facile electrochemical deposition route was reported for the direct growth of the porous Gd-doped CeO2. The formation process of Gd-doped CeO2 composites was investigated. The obtained deposits were characterized by SEM, EDS, XRD, and XPS. The porous Gd3+- doped CeO2 (10 at% Gd) displays a typical type I adsorption isotherm and yields a large specific surface area of 135 m2/g. As Gd3+ ions were doped into CeO2 lattice, the absorption spectrum of Gd3+-doped CeO2 nanocrystals exhibited a red shift compared with porous CeO2 nanocrystals and bulk CeO2, and the luminescence of Gd3+-doped CeO2 deposits was remarkably enhanced due to the presence of more oxygen vacancies. In addition, the strong magnetic properties of Gd-doped CeO2 (10 at% Gd) were observed, which may be caused by Gd3+ ions or more oxygen defects in deposits. In addition, the catalytic activity of porous Gd-doped CeO2 toward CO oxidation was studied

    Estimation of the Global Health Impacts of Air Pollution

    Get PDF
    Air pollution is increasingly recognized as a significant contributor to global health outcomes. A methodological framework for evaluating the global health related outcomes of outdoor and indoor (household) air pollution is presented and validated for the year 2005. Ambient concentrations of PM2.5 re estimated with a combination of energy and atmospheric models, with detailed representation of urban and rural spatial exposures. Populations dependent on solid fuels are established with household survey data. Health impacts for outdoor and household air pollution are independently calculated using the fractions of disease that can be attributed to ambient air pollution exposure and solid fuel use. Estimated ambient pollution concentrations indicate that more than 80% of the population exceeds the WHO Air Quality Guidelines in 2005. In addition, 3.26 billion people were found to use solid fuel for cooking in three regions of Sub Saharan Africa, South Asia and Pacific Asia in 2005. Outdoor air pollution results in 2.7 million deaths or 23 million DALYs while household air pollution from solid fuel use and related indoor smoke results in 2.1 million deaths or 41.6 million DALYs. The higher morbidity from household air pollution can be attributed to children below the age of five in Sub Saharan Africa and South Asia. The burden of disease from air pollution is found to be significant, thus indicating the importance of policy interventions

    Search for a massive invisible particle X0X^0 in B+e+X0B^{+}\to e^{+}X^{0} and B+μ+X0B^{+}\to \mu^{+}X^{0} decays

    Full text link
    We present a search for a non-Standard-Model invisible particle X0X^0 in the mass range 0.1-1.8GeV/c20.1\textrm{-}1.8 \,{\rm GeV}/{c^2} in B+e+X0B^{+}\to e^{+} X^{0} and B+μ+X0B^{+}\to \mu^{+} X^{0} decays. The results are obtained from a 711 fb1711~{\rm fb}^{-1} data sample that corresponds to 772×106BBˉ772 \times 10^{6} B\bar{B} pairs, collected at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB e+ee^+ e^- collider. One BB meson is fully reconstructed in a hadronic mode to determine the momentum of the lepton of the signal decay in the rest frame of the recoiling partner BB meson. We find no evidence of a signal and set upper limits on the order of 10610^{-6}.Comment: 8 pages, 4 figures, 3 table

    Direct measurement of the pion valence quark momentum distribution, the pion light-cone wave function squared

    Full text link
    We present the first direct measurements of the pion valence quark momentum distribution which is related to the square of the pion light-cone wave function. The measurements were carried out using data on diffractive dissociation of 500 GeV/c π\pi^- into di-jets from a platinum target at Fermilab experiment E791. The results show that the qqˉ>|q\bar {q}> light-cone asymptotic wave function, which was developed using perturbative QCD methods, describes the data well for Q210 (GeV/c)2Q^2 \sim 10 ~{\rm (GeV/c)^2} or more. We also measured the transverse momentum distribution of the diffractive di-jets.Comment: 13 pages, 4 figure
    corecore