Risk of Helicobacter pylori infection among long-term residents in developing countries

The seroprevalence and incidence of Helicobacter pylori infection were determined among 312 North American missionaries who were serving in developing countries between 1967 and 1984. The majority (81%) resided in sub-Saharan Africa. When initially evaluated, the missionaries had a mean age of 40 years, 65% were female, and all were of white race/ethnicity. An ELISA showed that the initial prevalence of IgG antibody to H. pylori was 17%. After a mean of 7.4 years of service (1917 person-years of exposure), 37 (14%) of 259 initially seronegative subjects seroconverted to anti-H. pylori, giving an annual incidence of 1.9%. These data indicate a relatively higher risk of H. pylori infection among missionaries compared with an annual incidence of seroconversion of 0.3-1.0% in industrialized nations. Long-term residents in developing countries should be evaluated for H. pylori infection when gastrointestinal symptoms develop

Search for electroweak production of single top quarks in ppˉp\bar{p} collisions.

We present a search for electroweak production of single top quarks in the electron+jets and muon+jets decay channels. The measurements use ~90 pb^-1 of data from Run 1 of the Fermilab Tevatron collider, collected at 1.8 TeV with the DZero detector between 1992 and 1995. We use events that include a tagging muon, implying the presence of a b jet, to set an upper limit at the 95% confidence level on the cross section for the s-channel process ppbar->tb+X of 39 pb. The upper limit for the t-channel process ppbar->tqb+X is 58 pb. (arXiv

Studies of WW and WZ production and limits on anomalous WW gamma and WWZ couplings

Evidence of anomalous WW and WZ production was sought in pbar{p} collisions at a center-of-mass energy of sqrt(s) = 1.8 TeV. The final states $WW (WZ) to mu-nu-jet-jet + X, WZ to mu-nu-e-e + X and WZ to e-nu-e-e + X were studied using a data sample corresponding to an integrated luminosity of approximately 90 pb-1. No evidence of anomalous diboson production was found. Limits were set on anomalous WWgamma and WWZ couplings and were combined with our previous results. The combined 95% confidence level anomalous coupling limits for Lambda=2 TeV are -0.25 LE Delta-kappa LE 0.39 (lambda=0) and -0.18 LE lambda LE 0.19 (Delta \kappa = 0), assuming the WWgamma couplings are equal to the WWZ couplings

A direct measurement of w boson decay width

Based on 85 pb$^{-1}$ data of \ppbar collisions at $\sqrt{s}=1.8$ \tev\ collected using the D{\O}detector at Fermilab during the 1994-1995 run of the Tevatron, we present a direct measurement of the total decay width of the \wb\ boson, $\Gamma_W$. The width is determined from the transverse mass spectrum in the $W \to e+\nu_e$ decay channel and found to be $\Gamma_W = 2.23^{+ 0.15}_{- 0.14}$(stat.)$\pm 0.10$(syst.)GeV, consistent with the expectation from the standard model