Determination of the strange quark mass from Cabibbo-suppressed tau decays with resummed perturbation theory in an effective scheme

We present an analysis of the m_s^2-corrections to Cabibbo-suppressed tau lepton decays employing contour improved resummation within an effective scheme which is an essential new feature as compared to previous analyses. The whole perturbative QCD dynamics of the tau-system is described by the beta-function of the effective coupling constant and by two gamma-functions for the effective mass parameters of the strange quark in different spin channels. We analyze the stability of our results with regard to high-order terms in the perturbative expansion of the renormalization group functions. A numerical value for the strange quark mass in the MS scheme is extracted m_s(M_\tau)=130\pm 27_{exp}\pm 9_{th} MeV. After running to the scale 1 GeV this translates into m_s(1 GeV)=176 \pm 37_{exp}\pm 13_{th} MeV.Comment: 32 pages, latex, 4 postscript figures, revised version to appear in European Physical Journal C, discussion of the choice of the moments added, some errors correcte

Asymptotic structure of perturbative series for τ\tau lepton decay observables: ms2m_s^2 corrections

In a previous paper we performed an analysis of asymptotic structure of perturbation theory series for semileptonic $\tau$-lepton decays in massless limit. We extend our analysis to the Cabibbo suppressed $\Delta S=1$ decay modes of the $\tau$ lepton. In particular we address the problem of $m_s^2$ corrections to theoretical formulas. The properties of the asymptotic behavior of the finite order perturbation theory series for the coefficient functions of the $m_s^2$ corrections are studied.Comment: 25 page

Asymptotic structure of perturbative series for tau lepton observables

We analyze tau lepton decay observables, namely moments of the hadronic spectral density in the finite energy interval (0,M_\tau), within finite order perturbation theory including \alpha_s^4 corrections. The start of asymptotic growth of perturbation theory series is found at this order in a scheme invariant manner. We establish the ultimate accuracy of finite order perturbation theory predictions and discuss the construction of optimal observables.Comment: 21 page

Heavy baryons

We review the experimental and theoretical status of baryons containing one heavy quark. The charm and bottom baryon states are classified and their mass spectra are listed. The appropriate theoretical framework for the description of heavy baryons is the Heavy Quark Effective Theory, whose general ideas and methods are introduced and illustrated in specific examples. We present simple covariant expressions for the spin wave functions of heavy baryons including p--wave baryons. The covariant spin wave functions are used to determine the Heavy Quark Symmetry structure of flavour--changing current--induced transitions between heavy baryons as well as one--pion and one--photon transitions between heavy baryons of the same flavour. We discuss $1/m_Q$ corrections to the current--induced transitions as well as the structure of heavy to light baryon transitions. Whenever possible we attempt to present numbers to compare with experiment by making use of further model--dependent assumptions as e.g. the constituent picture for light quarks. We highlight recent advances in the theoretical understanding of the inclusive decays of hadrons containing one heavy quark including polarization. For exclusive semileptonic decays we discuss rates, angular decay distributions and polarization effects. We provide an update of the experimental and theoretical status of lifetimes of heavy baryons and of exclusive nonleptonic two body decays of charm baryons.Comment: 93 pages, 18 figures not included, latex, DESY 94-095, MZ-THEP-94-0

A systematic review and meta-analysis of the effectiveness of antiseptics for meatal cleaning in the prevention of catheter associated urinary tract infections

Background: Catheter-associated urinary tract infections (CAUTIs) are among the most common healthcare-associated infections. Antiseptic cleaning of the meatal area before and during catheter use may reduce the risk of CAUTIs. Aim: To undertake a systematic review of the literature and meta-analysis of studies investigating the effectiveness of antiseptic cleaning before urinary catheter insertion and during catheter use for prevention of CAUTIs. Methods: Electronic databases were searched to identify randomized controlled trials. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated and compared across intervention and control groups using DerSimonian–Laird random-effects model. Subgroup analyses were performed. Heterogeneity was estimated using the I2 statistic. Findings: In total, 2665 potential papers were identified; of these, 14 studies were eligible for inclusion. There was no difference in the incidence of CAUTIs when comparing antiseptic and non-antiseptic agents (pooled OR 0.90, 95% CI 0.73–1.10; P=0.31), or when comparing different agents: povidone-iodine vs routine care; povidone-iodine vs soap and water; chlorhexidine vs water; povidone-iodine vs saline; povidone-iodine vs water; and green soap and water vs routine care (P > 0.05 for all). Comparison of an antibacterial agent with routine care indicated near significance (P=0.06). There was no evidence of heterogeneity (I2=0%; P > 0.05). Subgroup analyses showed no difference in the incidence of CAUTIs in terms of country, setting, risk of bias, sex and frequency of administration. Conclusions: There were no differences in CAUTI rates, although methodological issues hamper generalizability of this finding. Antibacterial agents may prove to be significant in a well-conducted study. The present results provide good evidence to inform infection control guidelines in catheter management

EDC-37 Deflagration Rates at Elevated Pressures

We report deflagration rates on EDC-37 at high pressures. Experiments are conducted using the Lawrence Livermore National Laboratory High Pressure Strand Burner (HPSB) apparatus. The HPSB contains a deflagrating sample in a small volume, high pressure chamber. The sample consists of nine, 6.35 mm diameter, 6.35 mm length cylinders stacked on end, with burn wires placed between cylinders. Sample deflagration is limited to the cross-sectional surface of the cylinder by coating the cylindrical surface of the tower with Halthane 88-2 epoxy. Sample deflagration is initiated on one end of the tower by a B/KNO{sub 3} and HNS igniter train. Simultaneous temporal pressure history and burn front time of arrival measurements yield the laminar deflagration rate for a range of pressures and provide insight into deflagration uniformity. These measurements are one indicator of overall thermal explosion violence. Specific details of the experiment and the apparatus can be found in the literature

Deflagration Behavior of PBX 9501 at Elevated Temperature and Pressure

We report the deflagration behavior of PBX 9501 at pressures up to 300 MPa and temperatures of 150-180 C where the sample has been held at the test temperature for several hours before ignition. The purpose is to determine the effect on the deflagration behavior of material damage caused by prolonged exposure to high temperature. This conditioning is similar to that experienced by an explosive while it being heated to eventual explosion. The results are made more complicated by the presence of a significant thermal gradient along the sample during the temperature ramp and soak. Three major conclusions are: the presence of nitroplasticizer makes PBX 9501 more thermally sensitive than LX-04 with an inert Viton binder; the deflagration behavior of PBX 9501 is more extreme and more inconsistent than that of LX-04; and something in PBX 9501 causes thermal damage to 'heal' as the deflagration proceeds, resulting in a decelerating deflagration front as it travels along the sample