234 research outputs found

    Search for time-dependent B0s - B0s-bar oscillations using a vertex charge dipole technique

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    We report a search for B0s - B0s-bar oscillations using a sample of 400,000 hadronic Z0 decays collected by the SLD experiment. The analysis takes advantage of the electron beam polarization as well as information from the hemisphere opposite that of the reconstructed B decay to tag the B production flavor. The excellent resolution provided by the pixel CCD vertex detector is exploited to cleanly reconstruct both B and cascade D decay vertices, and tag the B decay flavor from the charge difference between them. We exclude the following values of the B0s - B0s-bar oscillation frequency: Delta m_s < 4.9 ps-1 and 7.9 < Delta m_s < 10.3 ps-1 at the 95% confidence level.Comment: 18 pages, 3 figures, replaced by version accepted for publication in Phys.Rev.D; results differ slightly from first versio

    Dark halo microphysics and massive black hole scaling relations in galaxies

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    We investigate the black hole (BH) scaling relation in galaxies using a model in which the galaxy halo and central BH are a self-gravitating sphere of dark matter (DM) with an isotropic, adiabatic equation of state. The equipotential where the escape velocity approaches the speed of light defines the horizon of the BH. We find that the BH mass (m•) depends on the DM entropy, when the effective thermal degrees of freedom (F) are specified. Relations between BH and galaxy properties arise naturally, with the BH mass and DM velocity dispersion following m• ∝ σF/2 (for global mean density set by external cosmogony). Imposing observationally derived constraints on F provides insight into the microphysics of DM. Given that DM velocities and stellar velocities are comparable, the empirical correlation between m• and stellar velocity dispersions σ⋆ implies that 7 6 the dense dark envelope surrounding the BH approaches the mean density of the BH itself, while the outer halo can show a nearly uniform kpc-scale core resembling those observed in galaxies

    Methods to determine the interactions of micro- and nanoparticles with mucus

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    The present review provides an overview of methods and techniques for studying interactions of micro- and nanoparticulate drug delivery system with mucus. Nanocarriers trapped by mucus are featuring a change in particle size and zeta potential that can be utilized to predict their mucus permeation behavior. Furthermore, interactions between nanoparticulate drug delivery systems and mucus layer modify the viscoelasticity of mucus which can be detected via rheological studies and quartz crystal microbalance with dissipation monitoring (QCM-D) analysis. To have a closer look at molecular interactions between drug carrier and mucus small-angle neutron scattering (SANS) is an appropriate analysis technique. Moreover, different methods to determine particle diffusion in mucus such as the newly established Transwell diffusion system, rotating silicone tube technique, multiple-particle tracking (MPT) and diffusion NMR are summarized within this review. The explanations and discussed pros and cons of collated methods and techniques should provide a good starting point for all those looking forward to move in this interesting field

    Effects of maternal education on diet, anemia, and iron deficiency in Korean school-aged children

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    <p>Abstract</p> <p>Background</p> <p>We investigated the relationship among socioeconomic status factors, the risk of anemia, and iron deficiency among school-aged children in Korea.</p> <p>Methods</p> <p>The sample consisted of fourth-grade students aged 10 y recruited from nine elementary schools in Korean urban areas in 2008 (<it>n </it>= 717). Anthropometric and blood biochemistry data were obtained for this cross-sectional observational study. Anemia was defined as hemoglobin levels lower than 11.5 g/dl. Iron deficiency was defined as serum iron levels lower than 40 ug/dl. We also obtained data on parental education from questionnaires and on children's diets from 3-day food diaries. Parental education was categorized as low or high, with the latter representing an educational level beyond high school.</p> <p>Results</p> <p>Children with more educated mothers were less likely to develop anemia (<it>P </it>= 0.0324) and iron deficiency (<it>P </it>= 0.0577) than were those with less educated mothers. This group consumed more protein (<it>P </it>= 0.0004) and iron (<it>P </it>= 0.0012) from animal sources than did the children of less educated mothers, as reflected by their greater consumption of meat, poultry, and derivatives (<it>P </it>< 0.0001). Logistic regression analysis revealed a significant inverse relationship between maternal education and the prevalence of anemia (odds ratio: 0.52; 95% confidence interval: 0.32, 0.85).</p> <p>Conclusions</p> <p>As a contributor to socioeconomic status, maternal education is important in reducing the risk of anemia and iron deficiency and in increasing children's consumption of animal food sources.</p

    Past, Present, and Future X-Ray and Gamma-Ray Missions

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    X- and -ray astronomy began in the early sixties of the last century with balloons flights, sounding rocket experiment and satellites. Long before space satellite detected X- and -rays emitted by cosmic sources, scientists had known that the Universe should be producing these photons. In this chapter we provided an overview of past and present missions that has made the X- and -ray astronomy an integral part of astronomical research, and prospects of future developments

    Surgical Management of Localized Scleroderma

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