822 research outputs found

    Bioviolence: Preventing Biological Terror and Crime

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    Clinical Prognostic Value of RNA Viral Load and CD4 Cell Counts during Untreated HIV-1 Infection—A Quantitative Review

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    Background: The prognostic value of CD4 counts and RNA viral load for identifying treatment need in HIV-infected individuals depends on (a) variation within and among individuals, and (b) relative risks of clinical progression per unit CD4 or RNA difference. Methodology/Principal Findings: We reviewed these measurements across (a) 30 studies, and (b) 16 cohorts of untreated seropositive adults. Median within-population interquartile ranges were 74,000 copies/mL for RNA with no significant change during the course of infection; and 330 cells/ÎŒL for CD4, with a slight proportional increase over infection. Applying measurement and physiological fluctuations observed on chronically infected patients, we estimate that 45% of population-level variation in RNA, and 25% of variation in CD4, were due to within-patient fluctuations. Comparing a patient with RNA at upper 75th centile with a patient at median RNA, 5-year relative risks were 1.4 (95% CI 1.2-1.7) for AIDS and 1.5 (1.3-1.9) for death, without change over the course of infection. In contrast, for a patient with CD4 count at the lower 75th centile, relative risks increased from 1.0 at seroconversion to maxima of 6.3 (4.4-8.9) for AIDS and 5.5 (2.7-10.1) for death by year 6, when the population median had fallen to 300 cells/ ÎŒL. Below 300 cells/ÎŒL, prognostic power did not increase, due to a narrower CD4 range. Conclusions: Findings support the current WHO recommendation (used with clinical criteria) to start antiretroviral treatment in low-income settings at CD4 thresholds of 200-350 cells/ÎŒL, without pre-treatment RNA monitoring - while not precluding earlier treatment based on clinical, socio-demographic or public health criteria

    Vaginal Colonization with Staphylococcus aureus in Healthy Women: A Review of Four Studies

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    Four studies assessed the frequency of vaginal Staphylococcus aureus colonization in healthy women and associated risk factors. An association was found between S. aureus vaginal colonization and colonization at the labia minora and the anterior nares. Significant risk factors associated with an increased risk of vaginal S. aureus in at least one study were a history of genital herpes simplex infection, insertion of tampons without an applicator, and the use of Rely (Procter & Gamble) tampons. The use of systemic antibiotics within 2 weeks of the vaginal culture decreased the risk of recovery of S. aureus. The overall frequency of vaginal S. aureus in the 808 women in the four studies was 9.2%

    Transmission of HIV-1 infection in sub-Saharan Africa and effect of elimination of unsafe injections

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    During the past year, a group has argued that unsafe injections are a major if not the main mode of HIV-1 transmission\ud in sub-Saharan Africa. We review the main arguments used to question the epidemiological interpretations on the lead\ud role of unsafe sex in HIV-1 transmission, and conclude there is no compelling evidence that unsafe injections are a\ud predominant mode of HIV-1 transmission in sub-Saharan Africa. Conversely, though there is a clear need to eliminate\ud all unsafe injections, epidemiological evidence indicates that sexual transmission continues to be by far the major\ud mode of spread of HIV-1 in the region. Increased efforts are needed to reduce sexual transmission of HIV-1

    Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

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    Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ Îł, H → Z Z∗ →4l and H →W W∗ →lÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

    Standalone vertex ïŹnding in the ATLAS muon spectrometer

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    A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

    Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

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    A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction
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