1,326 research outputs found

    Comparative Cost‐effectiveness of Alternative Empiric Antimicrobial Treatment Options for Suspected Enterococcal Bacteremia

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/107482/1/phar1393.pd

    Azithromycin‐Warfarin Interaction: Are We Fishing with a Red Herring?

    Full text link
    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90099/1/phco.25.4.630.61028.pd

    Critical Statistical Charge for Anyonic Superconductivity

    Full text link
    We examine a criterion for the anyonic superconductivity at zero temperature in Abelian matter-coupled Chern-Simons gauge field theories in three dimensions. By solving the Dyson-Schwinger equations, we obtain a critical value of the statistical charge for the superconducting phase in a massless fermion-Chern-Simons model.Comment: 11 pages; to appear in Phys Rev

    A Dynamical Resolution of the Sigma Term Puzzle

    Full text link
    We propose a resolution of the puzzle posed by the discrepancy between the pion-nucleon sigma term inferred from pion-nucleon scattering, and that deduced from baryon mass splittings using the Zweig rule. We show that there is a significant hypercharge-dependent dynamical contribution to baryon masses, not hitherto included in the analysis, which may be estimated using the scale Ward identity, and computed by solution of the Schwinger-Dyson equation for the quark self-energy. We find that the discrepancy is completely resolved without the need for any Zweig rule violation.Comment: 14 pages and 4 figures (not included), plain TeX and harvmac, DFTT 92/69 and OUTP-92-35

    Running coupling and fermion mass in strong coupling QED

    Full text link
    Simple toy model is used in order to exhibit the technique of extracting the non-perturbative information about Green's functions in Minkowski space. The effective charge and the dynamical electron mass are calculated in strong coupling 3+1 QED by solving the coupled Dyson-Schwinger equations for electron and photon propagators. The minimal Ball-Chiu vertex was used for simplicity and we impose the Landau gauge fixing on QED action. The solution obtained separately in Euclidean and Minkowski space were compared, the latter one was extracted with the help of spectral technique.Comment: 23 pages, 4 figures, v4: revised and extended version, one introductory section adde

    New vector bosons in the electroweak sector: a renormalizable model with decoupling

    Get PDF
    A linear realization of a model of dynamical electroweak symmetry breaking describing additional heavy vector bosons is proposed. The model is a SU(2)_L x U(1) x SU(2)_L' x SU(2)_R' gauge theory, breaking at some high scale u to SU(2)_weak x U(1)_Y and breaking again in the standard way at the electroweak scale v to U(1)_(em). The model is renormalizable and reproduces the Standard Model in the limit u\to infinity. This decoupling property is shown to hold also at the level of radiative corrections by computing, in particular, the epsilon parameters.Comment: 39 pages, 16 Figures, Late

    A Giant Planet Undergoing Extreme-Ultraviolet Irradiation By Its Hot Massive-Star Host

    Get PDF
    The amount of ultraviolet irradiation and ablation experienced by a planet depends strongly on the temperature of its host star. Of the thousands of extrasolar planets now known, only six have been found that transit hot, A-type stars (with temperatures of 7,300–10,000 kelvin), and no planets are known to transit the even hotter B-type stars. For example, WASP-33 is an A-type star with a temperature of about 7,430 kelvin, which hosts the hottest known transiting planet, WASP-33b (ref. 1); the planet is itself as hot as a red dwarf star of type M (ref. 2). WASP-33b displays a large heat differential between its dayside and nightside2, and is highly inflated–traits that have been linked to high insolation3,4. However, even at the temperature of its dayside, its atmosphere probably resembles the molecule-dominated atmospheres of other planets and, given the level of ultraviolet irradiation it experiences, its atmosphere is unlikely to be substantially ablated over the lifetime of its star. Here we report observations of the bright star HD 195689 (also known as KELT-9), which reveal a close-in (orbital period of about 1.48 days) transiting giant planet, KELT-9b. At approximately 10,170 kelvin, the host star is at the dividing line between stars of type A and B, and we measure the dayside temperature of KELT-9b to be about 4,600 kelvin. This is as hot as stars of stellar type K4 (ref. 5). The molecules in K stars are entirely dissociated, and so the primary sources of opacity in the dayside atmosphere of KELT-9b are probably atomic metals. Furthermore, KELT-9b receives 700 times more extreme-ultraviolet radiation (that is, with wavelengths shorter than 91.2 nanometres) than WASP-33b, leading to a predicted range of mass-loss rates that could leave the planet largely stripped of its envelope during the main-sequence lifetime of the host star (ref. 6)

    KELT-10b: The First Transiting Exoplanet from the KELT-South Survey -- A Hot Sub-Jupiter Transiting a V = 10.7 Early G-Star

    Get PDF
    We report the discovery of KELT-10b, the first transiting exoplanet discovered using the KELT-South telescope. KELT-10b is a highly inflated sub-Jupiter mass planet transiting a relatively bright V=10.7V = 10.7 star (TYC 8378-64-1), with Teff_{eff} = 5948±745948\pm74 K, logg\log{g} = 4.3190.030+0.0204.319_{-0.030}^{+0.020} and [Fe/H] = 0.090.10+0.110.09_{-0.10}^{+0.11}, an inferred mass M_{*} = 1.1120.061+0.0551.112_{-0.061}^{+0.055} M_{\odot} and radius R_{*} = 1.2090.035+0.0471.209_{-0.035}^{+0.047} R_{\odot}. The planet has a radius RP_{P} = 1.3990.049+0.0691.399_{-0.049}^{+0.069} RJ_{J} and mass MP_{P} = 0.6790.038+0.0390.679_{-0.038}^{+0.039} MJ_{J}. The planet has an eccentricity consistent with zero and a semi-major axis aa = 0.052500.00097+0.000860.05250_{-0.00097}^{+0.00086} AU. The best fitting linear ephemeris is T0T_{0} = 2457066.72045±\pm0.00027 BJDTDB_{TDB} and P = 4.1662739±\pm0.0000063 days. This planet joins a group of highly inflated transiting exoplanets with a radius much larger and a mass much less than those of Jupiter. The planet, which boasts deep transits of 1.4%, has a relatively high equilibrium temperature of Teq_{eq} = 137723+281377_{-23}^{+28} K, assuming zero albedo and perfect heat redistribution. KELT-10b receives an estimated insolation of 0.8170.054+0.0680.817_{-0.054}^{+0.068} ×\times 109^9 erg s1^{-1} cm2^{-2}, which places it far above the insolation threshold above which hot Jupiters exhibit increasing amounts of radius inflation. Evolutionary analysis of the host star suggests that KELT-10b is unlikely to survive beyond the current subgiant phase, due to a concomitant in-spiral of the planet over the next \sim1 Gyr. The planet transits a relatively bright star and exhibits the third largest transit depth of all transiting exoplanets with V << 11 in the southern hemisphere, making it a promising candidate for future atmospheric characterization studies.Comment: 20 pages, 13 figures, 7 tables, accepted for publication in MNRA
    corecore