181 research outputs found

    Induction of rifampicin metabolism during treatment of tuberculous patients with daily and fully intermittent regimens containing the drug

    Get PDF
    Self-induction of rifampicin metabolism during daily and intermittent chemotherapy was studied by monitoring the changes in the serum half-life of the drug over a 4-week period in patients with pulmonary tuberculosis. Rifampicin 450 mg was administered to 8 patients who received treatment daily, 7 on thrice-weekly and 7 others on twice-weekly treatment. Serum half-life was computed from concentrations of the drug determined at 3, 4½ and 6 hours after drug administration, on admission and at 1, 2 and 4 weeks after start of treatment. In the daily series, the mean serum half-life decreased from 4.9 hours on admission to 3.6 hours at 1 week (P = 0.02), and treatment beyond this had no further effect. In the thrice-weekly series, maximal induction was observed at the 2nd week, the mean values on admission and at 2 weeks being 5.8 and 3.7 hours, respectively (P < 0.01). In the twiceweekly series, maximal induction was observed only at the 4th week, the mean values on admission and at 4 weeks being 4.9 and 3.7 hours, respectively (P < 0.01). Serum activity of gamma glutamyl transferase was not found to be a suitable in vivo marker to monitor induction of the hepatic microsomal enzymes as no significant changes were observed in the activity of this enzyme in any of the 3 series during the 4-week period

    Optimal phase estimation in quantum networks

    Full text link
    We address the problem of estimating the phase phi given N copies of the phase rotation u(phi) within an array of quantum operations in finite dimensions. We first consider the special case where the array consists of an arbitrary input state followed by any arrangement of the N phase rotations, and ending with a POVM. We optimise the POVM for a given input state and fixed arrangement. Then we also optimise the input state for some specific cost functions. In all cases, the optimal POVM is equivalent to a quantum Fourier transform in an appropriate basis. Examples and applications are given.Comment: 9 pages, 2 figures; this is an extended version of arXiv:quant-ph/0609160. v2: minor corrections in reference

    Quantum search on graphene lattices

    Get PDF
    We present a continuous-time quantum search algorithm on a graphene lattice. This provides the sought- after implementation of an efficient continuous-time quantum search on a two-dimensional lattice. The search uses the linearity of the dispersion relation near the Dirac point and can find a marked site on a graphene lattice faster than the corresponding classical search. The algorithm can also be used for state transfer and communication

    Search for the Flavor-Changing Neutral-Current Decays D+π+μ+μD^+\to \pi^+ \mu^+ \mu^- and D+π+e+eD^+\to \pi^+ e^+ e^-

    Full text link
    We report the results of a search for the flavor-changing neutral-current decays D+π+μ+μD^+\rightarrow \pi^+ \mu^+ \mu^- and D+π+e+eD^+\rightarrow \pi^+ e^+ e^- in data from Fermilab charm hadroproduction experiment E791. No signal above background is found, and we obtain upper limits on branching fractions, B(D+π+μ+μ)<1.8×105B(D^+\rightarrow \pi^+ \mu^+ \mu^-) < 1.8 \times 10^{-5} and B(D+π+e+e)<6.6×105B(D^+\rightarrow \pi^+ e^+ e^-) < 6.6 \times 10^{-5}, at the 90\% confidence level.Comment: nine pages with figures; compressed, uuencoded postscrip

    Fermilab E791

    Get PDF
    Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.Comment: 4 pages, 1 figure, LaTe

    Measurement of the Ds Lifetime

    Full text link
    We report the results of a precise measurement of the Ds meson lifetime based on 1662 +/- 56 fully reconstructed Ds -> phi pi decays, from the charm hadroproduction experiment E791 at Fermilab. Using an unbinned maximum likelihood fit, we measure the Ds lifetime to be 0.518 +/- 0.014 +/- 0.007 ps. The ratio of the measured Ds lifetime to the world average D0 lifetime is 1.25 +/- 0.04. This result differs from unity by six standard deviations, indicating significantly different lifetimes for the Ds and the D0.Comment: 12 pages, 3 figures, 2 table. LaTe

    Effect of doping on the dielectric properties of cerium oxide in the microwave and far-infrared frequency range

    Get PDF
    Cerium oxide (CeO2) has been prepared as a ceramic dielectric resonator by a conventional solid-state ceramic route. The sintered CeO2 has a high dielectric quality factor (Q×f), Q value of 10 000 at 6 GHz with a relative permittivity (ε′) of 23, and temperature coefficient of resonant frequency (τf of -53 ppm/°C. The Q value increases to 20 000 at 6 GHz when the CeO2 is doped with 1 mol% CaCO3. Higher levels of CaCO3 doping lowers the Q and ε′ values and simultaneously decreases τf. TiO2 doping decreases τf and slightly increases ε′, but deceases the Q value. The Q value of pure CeO2 increases to 105 000 at a frequency of 5.58 GHz when it is cooled to 30 K, whereas Q ≈ 85 000 at 5.48 GHz for 1-mol%-CaCO3-doped CeO2 at 30 K

    Study of the Ds+ππ+π+D^+_s \to \pi^- \pi^+ \pi^+ decay and measurement of f0f_0 masses and widths

    Full text link
    From a sample of 848 ±\pm 44 Ds+ππ+π+D_s^+ \to \pi^- \pi^+ \pi^+ decays, we find Γ(Ds+ππ+π+)/Γ(Ds+ϕπ+)=0.245±0.0280.012+0.019\Gamma(D_s^+ \to \pi^- \pi^+ \pi^+) / \Gamma(D_s^+ \to \phi \pi^+) = 0.245 \pm 0.028^{+0.019}_{-0.012} . Using a Dalitz plot analysis of this three body decay, we find significant contributions from the channels ρ0(770)π+\rho^0(770)\pi^+, ρ0(1450)π+\rho^0(1450)\pi^+, f0(980)π+f_0(980)\pi^+, f2(1270)π+f_2(1270)\pi^+, and f0(1370)π+f_0(1370)\pi^+. We present also the values obtained for masses and widths of the resonances f0(980)f_0(980) and f0(1370)f_0(1370).Comment: 10 pages, 3 eps figure
    corecore