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- Schael, S, et al.
(författare)
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Precision electroweak measurements on the Z resonance
- 2006
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Ingår i: Physics Reports. - : Elsevier BV. - 0370-1573 .- 1873-6270. ; 427:5-6, s. 257-454
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Forskningsöversikt (refereegranskat)abstract
- 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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| 3. |
- Chaturvedi, S., et al.
(författare)
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Effect of atorvastatin in elderly patients with a recent stroke or transient ischemic attack
- 2009
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Ingår i: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 72:8, s. 688-94
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: It is unclear whether patients age 65 years and over with a recent stroke or TIA benefit from statin treatment to a similar degree as younger patients. METHODS: The 4,731 patient cohort in the SPARCL study was divided into an elderly group (65 and over) and a younger group. The primary endpoint (fatal or nonfatal stroke) and secondary endpoints were analyzed, with calculation of the hazard ratio (HR) and p values from a Cox regression model. RESULTS: There were 2,249 patients in the elderly group and 2,482 in the younger group. The baseline LDL (133 mg/dL) and total cholesterol were comparable in the two groups. The elderly and younger groups had a 61.4 mg/dL and 58.7 mg/dL decrease in mean LDL during the trial. The primary endpoint was reduced by 26% in younger patients (HR 0.74, 0.57-0.96, p = 0.02) and by 10% in elderly subjects (HR 0.90, 0.73-1.11, p = 0.33). A test of heterogeneity for a treatment-age interaction was not significant (p = 0.52). The risk of stroke or TIA (HR 0.79, p = 0.01), major coronary events (HR 0.68, p = 0.035), any coronary heart disease event (HR 0.61, p = 0.0006), and revascularization procedures (HR 0.55, p = 0.0005) was reduced in the elderly group. CONCLUSIONS: There was no heterogeneity in the stroke reduction seen with atorvastatin in the elderly and younger groups. Cardiac events and revascularization procedures were also lower in both the elderly and younger subgroups treated with atorvastatin. These results support the use of atorvastatin in elderly patients with recent stroke or TIA.
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