Mechanisms of T cell organotropism

F.M.M.-B. is supported by the British Heart Foundation, the Medical Research Council of the UK and the Gates Foundation

Measurement of W-pair production in e+e−e^+ e^- collisions at 189 GeV

The production of W-pairs is analysed in a data samplecollected by ALEPH at a mean centre-of-mass energy of 188.6 GeV,corresponding to an integrated luminosity of 174.2 pb^-1. Crosssections are given for different topologies of W decays intoleptons or hadrons. Combining all final states and assumingStandard Model branching fractions, the total W-pair cross sectionis measured to be 15.71 +- 0.34 (stat) +- 0.18 (syst) pb.Using also the W-pair data samples collected by ALEPH at lowercentre-of-mass energies, the decay branching fraction of the W bosoninto hadrons is measured to be BR (W hadrons) = 66.97+- 0.65 (stat) +- 0.32 (syst) %, allowing a determination of theCKM matrix element |V(cs)|= 0.951 +- 0.030 (stat) +- 0.015 (syst)

Searches for neutral Higgs bosons in e+e−e^{+}e^{-} collisions at centre-of-mass energies from 192 to 202 GeV

Searches for neutral Higgs bosons are performed with the 237 pb^-1 of data collected in 1999 by the ALEPH detector at LEP, for centre-of-mass energies between 191.6 and 201.6 GeV. These searches apply to Higgs bosons within the context of the Standard Model and its minimal supersymmetric extension (MSSM) as well as to invisibly decaying Higgs bosons. No evidence of a signal is seen. A lower limit on the mass of the Standard Model Higgs boson of 107.7 GeV/c^2 at 95% confidence level is set. In the MSSM, lower limits of 91.2 and 91.6 GeV/c^2 are derived for the masses of the neutral Higgs bosons h and A, respectively. For a Higgs boson decaying invisibly and produced with the Standard Model cross section, masses below 106.4 GeV/c^2 are excluded

Determination of sin2 θeff w using jet charge measurements in hadronic Z decays

The electroweak mixing angle is determined with high precision from measurements of the mean difference between forward and backward hemisphere charges in hadronic decays of the Z. A data sample of 2.5 million hadronic Z decays recorded over the period 1990 to 1994 in the ALEPH detector at LEP is used. The mean charge separation between event hemispheres containing the original quark and antiquark is measured for bb̄ and cc̄ events in subsamples selected by their long lifetimes or using fast D*'s. The corresponding average charge separation for light quarks is measured in an inclusive sample from the anticorrelation between charges of opposite hemispheres and agrees with predictions of hadronisation models with a precision of 2%. It is shown that differences between light quark charge separations and the measured average can be determined using hadronisation models, with systematic uncertainties constrained by measurements of inclusive production of kaons, protons and A's. The separations are used to measure the electroweak mixing angle precisely as sin2 θeff w = 0.2322 ± 0.0008(exp. stat.) ±0.0007(exp. syst.) ± 0.0008(sep.). The first two errors are due to purely experimental sources whereas the third stems from uncertainties in the quark charge separations

Measurement of the W mass by direct reconstruction in e+e−e^+ e^- collisions at 172 GeV

The mass of the W boson is obtained from reconstructed invariant mass distributions in W-pair events. The sample of W pairs is selected from 10.65~pb$^{-1}$ collected with the ALEPH detector at a mean centre-of-mass energy of 172.09 \GEV. The invariant mass distribution of simulated events are fitted to the experimental distributions and the following W masses are obtained: $WW \to q\overline{q}q\overline{q } m_W = 81.30 +- 0.47(stat.) +- 0.11(syst.) GeV/c^2$, $WW \to l\nu q\overline{q}(l=e,\mu) m_W = 80.54 +- 0.47(stat.) +- 0.11(syst.) GeV/c^2$, $WW \to \tau\nu q\overline{q} m_W = 79.56 +- 1.08(stat.) +- 0.23(syst.) GeV/C62$. The statistical errors are the expected errors for Monte Carlo samples of the same integrated luminosity as the data. The combination of these measurements gives: $m_W = 80.80 +- 0.11(syst.) +- 0.03(LEP energy) GeV/^2$

Blood Eosinophils and outcomes in severe hospitalized exacerbations of COPD

Background Patients with moderate exacerbations of COPD and the eosinophilic phenotype have better outcomes with prednisolone. Whether this outcome is similar in patients hospitalized with a severe exacerbation of COPD is unclear. We investigated the rate of recovery of eosinophilic and noneosinophilic exacerbations in patients participating in a multicenter randomized controlled trial assessing health outcomes in hospitalized exacerbations. Methods Patients were recruited at presentation to the hospital with an exacerbation of COPD. They were stratified into groups according to eosinophilic exacerbations if the peripheral blood eosinophil count on admission was ≥ 200 cells/μL and/or ≥ 2% of the total leukocyte count. Admission details, serum C-reactive protein levels, length of stay, and subsequent rehospitalization data were compared between groups. Results A total of 243 patients with COPD (117 men) with a mean age of 71 years (range, 45-93 years) were recruited. The inpatient mortality rate was 3% (median time to death, 12 days; range, 9-16 days). The median absolute eosinophil count was 100 cells/μL (range, 10-1,500 cells/μL), and 25% met our criteria for an eosinophilic exacerbation; in this population, the mean length of stay (in days) was shorter than in patients with noneosinophilic exacerbations (5.0 [range, 1-19] vs 6.5 [range, 1-33]; P = .015) following treatment with oral corticosteroids and independent of treatment prior to admission. Readmission rates at 12 months were similar between groups. Conclusions The study patients presenting to the hospital with a severe eosinophilic exacerbation of COPD had a shorter length of stay. The exacerbations were usually not associated with elevated C-reactive protein levels, suggesting that better treatment stratification of exacerbations can be used

Blood Eosinophils and outcomes in severe hospitalized exacerbations of COPD

Background Patients with moderate exacerbations of COPD and the eosinophilic phenotype have better outcomes with prednisolone. Whether this outcome is similar in patients hospitalized with a severe exacerbation of COPD is unclear. We investigated the rate of recovery of eosinophilic and noneosinophilic exacerbations in patients participating in a multicenter randomized controlled trial assessing health outcomes in hospitalized exacerbations. Methods Patients were recruited at presentation to the hospital with an exacerbation of COPD. They were stratified into groups according to eosinophilic exacerbations if the peripheral blood eosinophil count on admission was ≥ 200 cells/μL and/or ≥ 2% of the total leukocyte count. Admission details, serum C-reactive protein levels, length of stay, and subsequent rehospitalization data were compared between groups. Results A total of 243 patients with COPD (117 men) with a mean age of 71 years (range, 45-93 years) were recruited. The inpatient mortality rate was 3% (median time to death, 12 days; range, 9-16 days). The median absolute eosinophil count was 100 cells/μL (range, 10-1,500 cells/μL), and 25% met our criteria for an eosinophilic exacerbation; in this population, the mean length of stay (in days) was shorter than in patients with noneosinophilic exacerbations (5.0 [range, 1-19] vs 6.5 [range, 1-33]; P = .015) following treatment with oral corticosteroids and independent of treatment prior to admission. Readmission rates at 12 months were similar between groups. Conclusions The study patients presenting to the hospital with a severe eosinophilic exacerbation of COPD had a shorter length of stay. The exacerbations were usually not associated with elevated C-reactive protein levels, suggesting that better treatment stratification of exacerbations can be used