912 research outputs found

    About the modern "experimental value" of W boson width.

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    It is shown that the methods which have been used up to now to determine the WW width from the ppˉp\bar p data confirm the SM predictions for some combinations of various phenomenological parameters, however, they do not give an independent value for the WW width. Moreover, the accuracy that could be achieved in future experimental checks of SM predictions for such quantities is limited by effects which require detailed theoretical study.Comment: Latex, 8 pages

    Antimicrobial Activity of Glucoprotamin: A Clinical Study of a New Disinfectant for Instruments

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    Abstract Objective: To determine the in vitro efficacy of glucoprotamin for the disinfection of instruments. Design: Prospective observational study. Setting: University women's hospital. Methods: Instruments were immersed in saline solution after use, and glucoprotamin was added to a concentration of 1.5% before soaking for 60 minutes. Biocidal activity was determined by the difference in colony-forming units (CFU) on instruments before and after disinfection. Results: One hundred thirty-seven instruments were collected during 10 days and exposed to a 1.5% dilution of glucoprotamin without prior washing. Bioburden before disinfection ranged from 2 × 105 to 7.1 × 107 CFU per instrument. Average bacterial killing was 5.98 log10 CFU ± 0.48 under aerobic conditions and 6.75 log10 CFU ± 0.54 under anaerobic conditions, despite the presence of large amounts of proteins on instruments that were frequently bloody. No vegetative bacteria were isolated in any sample after disinfection. Conclusion: This clinical study confirmed excellent in vitro efficacy of glucoprotamin without prior removal of proteins and debri

    Threshold bipower variation and the impact of jumps on volatility forecasting

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    This study reconsiders the role of jumps for volatility forecasting by showing that jumps have a positive and mostly significant impact on future volatility. This result becomes apparent once volatility is separated into its continuous and discontinuous components using estimators which are not only consistent, but also scarcely plagued by small sample bias. With the aim of achieving this, we introduce the concept of threshold bipower variation, which is based on the joint use of bipower variation and threshold estimation. We show that its generalization (threshold multipower variation) admits a feasible central limit theorem in the presence of jumps and provides less biased estimates, with respect to the standard multipower variation, of the continuous quadratic variation in finite samples. We further provide a new test for jump detection which has substantially more power than tests based on multipower variation. Empirical analysis (on the S&P500 index, individual stocks and US bond yields) shows that the proposed techniques improve significantly the accuracy of volatility forecasts especially in periods following the occurrence of a jump

    Photoluminescence Detected Doublet Structure in the Integer and Fractional Quantum Hall Regime

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    We present here the results of polarized magneto-photoluminescence measurements on a high mobility single-heterojunction. The presence of a doublet structure over a large magnetic field range (2>nu>1/6) is interpreted as possible evidence for the existence of a magneto-roton minima of the charged density waves. This is understood as an indication of strong electronic correlation even in the case of the IQHE limit.Comment: submitted to Solid State Communication

    Microbiological tests to predict treatment outcome in experimental device-related infections due to Staphylococcus aureus

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    Treatment outcome of experimental device-related infections cannot be predicted by the results of standard susceptibility tests such as MIC. Microorganisms involved in such infections have a slow growth rate and adhere to surfaces. Therefore, laboratory tests were developed taking into account these properties and compared with the treatment outcome in an animal model. Vancomycin, teicoplanin, ciprofloxacin and fleroxacin were tested alone, or in combination with rifampicin for their ability to cure experimental device-related infections in guinea pigs due to Staphylococcus aureus ATCC 29213. Rifampicin alone or in combination was significantly more effective than the other four drugs (P < 0·001). Combined treatment with rifampicin had a higher cure rate than rifampicin alone. Treatment success was not predicted by an antibiotic trough level exceeding the MIC at site of infection. In contrast, drug efficacy was predicted if the stationary-phase MBC was in the sensitive range, and if glass-adherent S. aureus was killed by low drug concentration

    Liquid Holdup Management by Predicting Steady State Turndown Rate in Wet Gas Pipeline Network

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    Now days, one of the greatest challenges in gas development is transport the fluid especially multiphase fluid to long distances and multiphase pipeline to sell point. Yet, a challenge to transport multiphase fluid is how to operate the systemsin operating a long distance, large diameter, and multiphase pipeline.The operating system include how to manage high liquid holdup, mainly built during low production rate (turn down rate) periods especially during transient operations such as restart and ramp-up, so that liquid surge arriving onshore will not exceed the liquid handling capacity of the slug catcher. The objective of this research is to predict liquid trapped in pipeline network by analysis turn down rate in order to determine minimal gas production rate for stable operation. This research was carried out by two steps: Simulation Approach and Optimization Techniques. Simulation approach include define fluid composition and built pipeline network configuration while optimization technique include conduct scenario for turn down rate. The fluid composition from wellhead to manifold is wet gas. First scenario and Second scenario of turndown rate yield minimum gas rate for stable operation. The pipeline has to be operated above 600 MMSCFD from peak gas production rate is 1200 MMSCFD (A-Manifold Mainline) and 60 MMSCFD from peak gas production rate is 150 MMSCFD for D-Manifold Mainline

    3D Bioprinting of Gelatin–Xanthan Gum Composite Hydrogels for Growth of Human Skin Cells

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    In recent years, bioprinting has attracted much attention as a potential tool for generating complex 3D biological constructs capable of mimicking the native tissue microenvironment and promoting physiologically relevant cell–cell and cell–matrix interactions. The aim of the present study was to develop a crosslinked 3D printable hydrogel based on biocompatible natural polymers, gelatin and xanthan gum at different percentages to be used both as a scaffold for cell growth and as a wound dressing. The CellInk Inkredible 3D printer was used for the 3D printing of hydrogels, and a glutaraldehyde solution was tested for the crosslinking process. We were able to obtain two kinds of printable hydrogels with different porosity, swelling and degradation time. Subsequently, the printed hydrogels were characterized from the point of view of biocompatibility. Our results showed that gelatin/xanthan-gum bioprinted hydrogels were biocompatible materials, as they allowed both human keratinocyte and fibroblast in vitro growth for 14 days. These two bioprintable hydrogels could be also used as a helpful dressing material

    Equal Efficacy of Glucoprotamin and an Aldehyde Product for Environmental Disinfection in a Hematologic Transplant Unit: A Prospective Crossover Trial

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    Background. The inanimate hospital environment has emerged as an important reservoir of nosocomial pathogens. In particular, multidrug-resistant pathogens, such as methicillin-resistant Staphylococcus aureus, Acinetobacter species, and Clostridium difficile, play a major role in the transmission of hospital-acquired infections. In Europe, aldehydes, chlorine, and quaternary ammonium compounds have been commonly used for environmental disinfection. Glucoprotamin, a newer active compound for disinfectants, has been clinically tested for disinfection of instruments but not for environmental disinfection. Objective. This study evaluated the antimicrobial effectiveness of a glucoprotamin-containing product (Incidin) compared with that of an aldehyde-containing product (Deconex), the current standard at our institution. Methods. This prospective crossover study was conducted in our access-restricted hematologic transplant unit. A total of 3,086 samples from the environment were processed and examined for overall bacterial burden as well as selectively for S. aureus, C. difficile, and gram-negative bacteria. Results. There was no significant difference in residual bacteria after disinfection between the 2 products in terms of overall burden and selected pathogens. Enterococci were the predominant pathogens recovered from surfaces, but no vancomycin-resistant enterococci were recovered. Similarly, C. difficile could not be found in the patients' environment, even in rooms, despite the use of selective media. Conclusion. The aldehyde-containing product (Deconex) and the glucoprotamin-containing product (Incidin) demonstrated similar efficacy against environmental contamination in a hematologic transplant unit with the application of selective media for C. difficile, S. aureus, and gram-negative bacteria in addition to standard mediu
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