9 research outputs found

    Dose-dependent relationship between prenatal exposure to fine particulates and exhaled carbon monoxide in non-asthmatic children. A population-based birth cohort study

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    Objectives: The main goal of the study was to assess possible association between fetal exposure to fi ne particulate matter (PM2.5) and exhaled carbon monoxide (eCO) measured in non-asthmatic children. Material and Methods: The subjects include 118 children taking part in an ongoing population-based birth cohort study in Kraków. Personal samplers of PM2.5 were used to measure fi ne particle mass in the fetal period and carbon monoxide (CO) in exhaled breath from a single exhalation effort at the age of 7. In the statistical analysis of the effect of prenatal PM2.5 exposure on eCO, a set of potential confounders, such as environmental tobacco smoke (ETS), city residence area, sensitization to house dust allergens and the occurrence of respiratory symptoms monitored over the seven-year follow-up was considered. Results: The level of eCO did not correlate with the self-reported ETS exposure recorded over the follow-up, however, there was a positive signifi cant relationship with the prenatal PM2.5 exposure (non-parametric trend p = 0.042). The eCO mean level was higher in atopic children (geometric mean = 2.06 ppm, 95% CI: 1.58–2.66 ppm) than in non-atopic ones (geometric mean = 1.57 ppm, 95% CI: 1.47–1.73 ppm) and the difference was statistically signifi cant (p = 0.036). As for the respiratory symptoms, eCO values were associated positively only with the cough severity score recorded in the follow-up (nonparametric trend p = 0.057). In the nested multivariable linear regression model, only the effects of prenatal PM2.5 and cough severity recorded in the follow-up were related to eCO level. The prenatal PM2.5 exposure represented 5.1%, while children’s cough represented only 2.6% of the eCO variability. Conclusion: Our study suggests that elevated eCO in non-asthmatic children may result from oxidative stress experienced in the fetal period and that heme oxygenase (HO) activity in body tissues may be programmed in the fetal period by the exposure to fi ne particulate matter

    Precision electroweak measurements on the Z resonance

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    Precision electroweak measurements on the Z resonance☆☆☆

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    We report on the final electroweak measurements performed with data taken at the Z resonance by the experiments operating at the electron-positron colliders SLC and LEP. The data consist of 17 million Z decays accumulated by the ALEPH, DELPHI, L3 and OPAL experiments at LEP, and 600 thousand Z decays by the SLID experiment using a polarised beam at SLC. The measurements include cross-sections, forward-backward asymmetries and polarised asymmetries. The mass and width of the Z boson, m(Z) and Gamma(Z), and its couplings to fermions, for example the p parameter and the effective electroweak mixing angle for leptons, are precisely measured: m(Z) = 91.1875 +/- 0.0021 GeV, Gamma(Z) = 2.4952 +/- 0.0023 GeV, rho(l) = 1.0050 +/- 0.0010, sin(2)theta(eff)(lept) = 0.23153 +/- 0.00016. The number of light neutrino species is determined to be 2.9840 +/- 0.0082, in agreement with the three observed generations of fundamental fermions. The results are compared to the predictions of the Standard Model (SM). At the Z-pole, electroweak radiative corrections beyond the running of the QED and QCD coupling constants are observed with a significance of five standard deviations, and in agreement with the Standard Model. Of the many Z-pole measurements, the forward-backward asymmetry in b-quark production shows the largest difference with respect to its SM expectation, at the level of 2.8 standard deviations. Through radiative corrections evaluated in the framework of the Standard Model, the Z-pole data are also used to predict the mass of the top quark, m(t) = 173(+10)(+13) GeV, and the mass of the W boson, m(W) = 80.363 +/- 0.032 GeV. These indirect constraints are compared to the direct measurements, providing a stringent test of the SM. Using in addition the direct measurements of m(t) and m(W), the mass of the as yet unobserved SM Higgs boson is predicted with a relative uncertainty of about 50% and found to be less than 285 GeV at 95% confidence level. (c) 2006 Elsevier B.V. All rights reserved
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