312 research outputs found

    Erythrocyte sedimentation rate as a marker of inflammation and ongoing coagulation in stroke and transient ischaemic attack

    Get PDF
    No abstract. South African Medical Journal Vol. 95 (8) 2005: 607-61

    Pneumococcal carriage in sub-Saharan Africa--a systematic review.

    Get PDF
    BACKGROUND: Pneumococcal epidemiology varies geographically and few data are available from the African continent. We assess pneumococcal carriage from studies conducted in sub-Saharan Africa (sSA) before and after the pneumococcal conjugate vaccine (PCV) era. METHODS: A search for pneumococcal carriage studies published before 2012 was conducted to describe carriage in sSA. The review also describes pneumococcal serotypes and assesses the impact of vaccination on carriage in this region. RESULTS: Fifty-seven studies were included in this review with the majority (40.3%) from South Africa. There was considerable variability in the prevalence of carriage between studies (I-squared statistic = 99%). Carriage was higher in children and decreased with increasing age, 63.2% (95% CI: 55.6-70.8) in children less than 5 years, 42.6% (95% CI: 29.9-55.4) in children 5-15 years and 28.0% (95% CI: 19.0-37.0) in adults older than 15 years. There was no difference in the prevalence of carriage between males and females in 9/11 studies. Serotypes 19F, 6B, 6A, 14 and 23F were the five most common isolates. A meta-analysis of four randomized trials of PCV vaccination in children aged 9-24 months showed that carriage of vaccine type (VT) serotypes decreased with PCV vaccination; however, overall carriage remained the same because of a concomitant increase in non-vaccine type (NVT) serotypes. CONCLUSION: Pneumococcal carriage is generally high in the African continent, particularly in young children. The five most common serotypes in sSA are among the top seven serotypes that cause invasive pneumococcal disease in children globally. These serotypes are covered by the two PCVs recommended for routine childhood immunization by the WHO. The distribution of serotypes found in the nasopharynx is altered by PCV vaccination

    The deep-subsurface sulfate reducer Desulfotomaculum kuznetsovii employs two methanol-degrading pathways

    Get PDF
    Methanol is generally metabolized through a pathway initiated by a cobalamine-containing methanol methyltransferase by anaerobic methylotrophs (such as methanogens and acetogens), or through oxidation to formaldehyde using a methanol dehydrogenase by aerobes. Methanol is an important substrate in deep-subsurface environments, where thermophilic sulfate-reducing bacteria of the genus Desulfotomaculum have key roles. Here, we study the methanol metabolism of Desulfotomaculum kuznetsovii strain 17T, isolated from a 3000-m deep geothermal water reservoir. We use proteomics to analyze cells grown with methanol and sulfate in the presence and absence of cobalt and vitamin B12. The results indicate the presence of two methanol-degrading pathways in D. kuznetsovii, a cobalt-dependent methanol methyltransferase and a cobalt-independent methanol dehydrogenase, which is further confirmed by stable isotope fractionation. This is the first report of a microorganism utilizing two distinct methanol conversion pathways. We hypothesize that this gives D. kuznetsovii a competitive advantage in its natural environment.Research was funded by grants of the Division of Chemical Sciences (CW-TOP 700.55.343) and Earth and Life Sciences (ALW 819.02.014) of The Netherlands Organisation for Scientific Research (NWO), the European Research Council (ERC grant 323009), and the Gravitation grant (024.002.002) of the Netherlands Ministry of Education, Culture and Scienceinfo:eu-repo/semantics/publishedVersio

    Scattering Theory and PT\mathcal{P}\mathcal{T}-Symmetry

    Full text link
    We outline a global approach to scattering theory in one dimension that allows for the description of a large class of scattering systems and their P\mathcal{P}-, T\mathcal{T}-, and PT\mathcal{P}\mathcal{T}-symmetries. In particular, we review various relevant concepts such as Jost solutions, transfer and scattering matrices, reciprocity principle, unidirectional reflection and invisibility, and spectral singularities. We discuss in some detail the mathematical conditions that imply or forbid reciprocal transmission, reciprocal reflection, and the presence of spectral singularities and their time-reversal. We also derive generalized unitarity relations for time-reversal-invariant and PT\mathcal{P}\mathcal{T}-symmetric scattering systems, and explore the consequences of breaking them. The results reported here apply to the scattering systems defined by a real or complex local potential as well as those determined by energy-dependent potentials, nonlocal potentials, and general point interactions.Comment: Slightly expanded revised version, 38 page

    Observation of associated near-side and away-side long-range correlations in √sNN=5.02  TeV proton-lead collisions with the ATLAS detector

    Get PDF
    Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

    Performance of the CMS Cathode Strip Chambers with Cosmic Rays

    Get PDF
    The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

    Four models of HIV counseling and testing: utilization and test results in South Africa.

    Get PDF
    BACKGROUND: HIV Counseling and Testing (HCT) is the point-of-entry for pathways of HIV care and prevention. However, HCT is not reaching many who are HIV infected and this may be related to the HCT provision model. We describe HCT utilization and HIV diagnosis using four models of HCT delivery: clinic-based, urban mobile, rural mobile, and stand-alone. METHODS: Using cross-sectional data from routine HCT provided in South Africa, we described client characteristics and HIV test results from information collected during service delivery between January 2009 and June 2012. RESULTS: 118,358 clients received services at clinic-based units, 18,597; stand-alone, 28,937; urban mobile, 38,840; and rural mobile, 31,984. By unit, clients were similar in terms of median age (range 28-31), but differed in sex distribution, employment status, prior testing, and perceived HIV risk. Urban mobile units had the highest proportion of male clients (52%). Rural mobile units reached the highest proportion of clients with no prior HCT (61%) and reporting no perceived HIV risk (64%). Overall, 10,862 clients (9.3%) tested HIV-positive. CONCLUSIONS: Client characteristics varied by HCT model. Importantly, rural and urban mobile units reached more men, first-time testers, and clients who considered themselves to be at low risk for HIV

    Novel facultative Methylocella strains are active methane consumers at terrestrial natural gas seeps

    Get PDF
    Natural gas seeps contribute to global climate change by releasing substantial amounts of the potent greenhouse gas methane and other climate-active gases including ethane and propane to the atmosphere. However, methanotrophs, bacteria capable of utilising methane as the sole source of carbon and energy, play a significant role in reducing the emissions of methane from many environments. Methylocella-like facultative methanotrophs are a unique group of bacteria that grow on other components of natural gas (i.e. ethane and propane) in addition to methane but a little is known about the distribution and activity of Methylocella in the environment. The purposes of this study were to identify bacteria involved in cycling methane emitted from natural gas seeps and, most importantly, to investigate if Methylocella-like facultative methanotrophs were active utilisers of natural gas at seep sites

    Flavor tagged time-dependent angular analysis of the B0s → J/ψϕ decay and extraction of ΔΓs and the weak phase ϕs in ATLAS

    Get PDF
    A measurement of the B0s→J/ψϕ decay parameters, updated to include flavor tagging is reported using 4.9  fb−¹ of integrated luminosity collected by the ATLAS detector from √s=7  TeV pp collisions recorded in 2011 at the LHC. The values measured for the physical parameters are ϕs=0.12±0.25(stat)±0.05(syst)  rad ΔΓs=0.053±0.021(stat)±0.010(syst)  ps−¹ Γs=0.677±0.007(stat)±0.004(syst)  ps−¹ |A∥(0)|2=0.220±0.008(stat)±0.009(syst) |A0(0)|2=0.529±0.006(stat)±0.012(syst) δ⊥=3.89±0.47(stat)±0.11(syst)  rad where the parameter ΔΓs is constrained to be positive. The S-wave contribution was measured and found to be compatible with zero. Results for ϕs and ΔΓs are also presented as 68% and 95% likelihood contours, which show agreement with the Standard Model expectations

    Addendum to ‘measurement of the tt̄ production cross-section using eμ events with b-tagged jets in pp collisions at √s= 7 and 8 TeV with the ATLAS detector’

    Get PDF
    The ATLAS measurement of the inclusive top quark pair (tt̄) cross-section σtt̄ in proton–proton collisions at √s=8 TeV has been updated using the final 2012 luminosity calibration. The updated cross-section result is: σtt¯=242.9±1.7±5.5±5.1±4.2pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, knowledge of the integrated luminosity and of the LHC beam energy. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. The measurement of the ratio of tt̄ cross-sections at √s=8 TeV and √s=7 TeV, and the √s=8 TeV fiducial measurement corresponding to the experimental acceptance of the leptons, have also been updated. The most precise measurement of the tt̄ cross-section (σtt̄) in proton–proton collisions at √s=8 TeV from the ATLAS Collaboration was made using events with an opposite-charge electron–muon pair and one or two b-tagged jets [1], and used a preliminary calibration of the integrated luminosity. The luminosity calibration has been finalised since [2] with a total uncertainty of 1.9%, corresponding to a substantial improvement on the previous uncertainty of 2.8%. Since the uncertainty on the integrated luminosity contributed 3.1% of the total 4.3% uncertainty on the σtt¯ measurement reported in [1], a significant improvement in the measurement is possible by using the new luminosity calibration, as documented in this Addendum. The new calibration corresponds to an integrated luminosity of 20.2 fb−¹ for the √s=8 TeV sample, a decrease of 0.2%. The cross-section was recomputed taking into account the effects on both the conversion of the tt¯ event yield to a cross-section, and the background estimates, giving a result of: σtt¯=242.9±1.7±5.5±5.1±4.2pb, where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, knowledge of the integrated luminosity, and of the LHC beam energy, giving a total uncertainty of 8.8 pb (3.6 %). The result is consistent with the theoretical prediction of 252.9−14.5+13.3 pb, calculated at next-to-next-to-leading-order with next-to-next-to-leading-logarithmic soft gluon terms with the top++ 2.0 program [3] as discussed in detail in Ref. [1]. The updated value of the ratio of cross-sections Rtt¯=σtt¯(8 TeV)/σtt¯(7 TeV) is: Rtt¯=1.328±0.024±0.015±0.038±0.001, with uncertainties defined as above, adding in quadrature to a total of 0.047. The largest uncertainty comes from the uncertainties on the integrated luminosities, considered to be uncorrelated between the √s=7 TeV and √s=8 TeV datasets. This result is 2.1σ below the expectation of 1.430±0.013 calculated from top++ 2.0 as discussed in Ref. [1]. The updated fiducial cross-sections, for a tt¯ decay producing an eμ pair within a given fiducial region, are shown in Table 1, updating Table 5 of Ref. [1]. The results are given both for the analysis requirements of pT>25GeV and |η|30GeV and |η|<2.4. They are given separately for the two cases where events with either one or both leptons coming from t→W→τ→ℓ rather than the direct decay t→W→ℓ(ℓ=e or μ) are included, or where the contributions involving τ decays are subtracted. The results shown for the √s=7 TeV data sample are unchanged with respect to those in Ref. [1]. The results for the top quark pole mass and limits on light supersymmetric top squarks presented in Ref. [1] are derived from √s=7 TeV and √s=8 TeV cross-section measurements taken together, and would be only slightly improved by the luminosity update described here
    corecore