Racial and ethnic differences in incident myocardial infarction in end-stage renal disease patients: The USRDS

African Americans have a greater risk of cardiovascular disease (CVD) than Caucasians in early chronic kidney disease; however, limited data describe racial and ethnic differences in the risk of incident myocardial infarction (MI) among patients with end-stage renal disease (ESRD). We conducted a prospective, observational cohort study among 271 102 incident dialysis patients receiving renal replacement therapy enrolled in the United States Renal Data System (USRDS) for whom Medicare was the primary insurer between 1995 and 2000. The incidence and risk of any MI (non-fatal or fatal) estimated by Cox proportional hazards models was the primary outcome of interest. Of those with prevalent CVD at baseline (118 708), 14 849 had an incident non-fatal MI compared with 9926 events for those without prevalent CVD (152 394). Patients with prevalent CVD had higher crude rates of combined fatal and non-fatal MI (99.3/1000 person-years vs 42.9/1000 person-years) compared with those without prevalent CVD. Among those with prevalent CVD, African Americans (adjusted relative risk (aRR)=0.65, 95% confidence interval (CI):0.62–0.68), Asian Americans (aRR=0.74, 95% CI: 0.66–0.83), and Hispanics (aRR=0.72, 95% CI: 0.68–0.77) were 26–35% less likely to have an incident MI compared to Caucasians. Similarly, among those without prevalent CVD, racial/ethnic minorities were 26–42% less likely to have an incident MI compared to Caucasians. We conclude that in a national setting where comparable access to dialysis and associated medical care, exist, racial/ethnic minorities were found to have a lower risk of non-fatal and fatal MI than Caucasians

Bone mineral density and risk of heart failure in older adults: The Cardiovascular Health Study

Background Despite increasing evidence of a common link between bone and heart health, the relationship between bone mineral density ( BMD ) and heart failure ( HF ) risk remains insufficiently studied. Methods and Results We investigated whether BMD measured by dual‐energy x‐ray absorptiometry was associated with incident HF in an older cohort. Cox models were stratified by sex and interactions of BMD with race assessed. BMD was examined at the total hip and femoral neck separately, both continuously and by World Health Organization categories. Of 1250 participants, 442 (55% women) developed HF during the median follow‐up of 10.5 years. In both black and nonblack women, neither total hip nor femoral neck BMD was significantly associated with HF ; there was no significant interaction by race. In black and nonblack men, total hip, but not femoral neck, BMD was significantly associated with HF , with evidence of an interaction by race. In nonblack men, lower total hip BMD was associated with higher HF risk (hazard ratio, 1.13 [95% CI, 1.01–1.26] per 0.1 g/cm 2 decrement), whereas in black men, lower total hip BMD was associated with lower HF risk (hazard ratio, 0.74 [95% CI, 0.59–0.94]). There were no black men with total hip osteoporosis. Among nonblack men, total hip osteoporosis was associated with higher HF risk (hazard ratio, 2.83 [95% CI, 1.39–5.74]) compared with normal BMD . Conclusions Among older adults, lower total hip BMD was associated with higher HF risk in nonblack men but lower risk in black men, with no evidence of an association in women. Further research is needed to replicate these findings and to study potential underlying pathways. </jats:sec

Top quark measurements at the Tevatron

The authors present top physics results from the CDF and D0 collaborations. The data were collected at the Fermilab Tevatron over the years 1992--1995 and correspond to approximately 110 pb{sup {minus}1} of p{anti p} collisions. Both experiments present determination of the t{anti t} production cross section using a variety of top decay channels, and refined measurements of the top mass

Measurement of the lepton charge asymmetry in W-boson decays produced in p-pbar collisions

We describe a measurement of the charge asymmetry of leptons from W boson decays in the rapidity range 0 enu, munu events from 110+/-7 pb^{-1}of data collected by the CDF detector during 1992-95. The asymmetry data constrain the ratio of d and u quark momentum distributions in the proton over the x range of 0.006 to 0.34 at Q2 \approx M_W^2. The asymmetry predictions that use parton distribution functions obtained from previously published CDF data in the central rapidity region (0.0<|y_l|<1.1) do not agree with the new data in the large rapidity region (|y_l|>1.1).Comment: 13 pages, 3 tables, 1 figur

Observation of Hadronic W Decays in t-tbar Events with the Collider Detector at Fermilab

We observe hadronic W decays in t-tbar -> W (-> l nu) + >= 4 jet events using a 109 pb-1 data sample of p-pbar collisions at sqrt{s} = 1.8 TeV collected with the Collider Detector at Fermilab (CDF). A peak in the dijet invariant mass distribution is obtained that is consistent with W decay and inconsistent with the background prediction by 3.3 standard deviations. From this peak we measure the W mass to be 77.2 +- 4.6 (stat+syst) GeV/c^2. This result demonstrates the presence of two W bosons in t-tbar candidates in the W (-> l nu) + >= 4 jet channel.Comment: 20 pages, 4 figures, submitted to PR

Search for charged Higgs decays of the top quark using hadronic tau decays

We present the result of a search for charged Higgs decays of the top quark, produced in $p\bar{p}$ collisions at $\surd s =$ 1.8 TeV. When the charged Higgs is heavy and decays to a tau lepton, which subsequently decays hadronically, the resulting events have a unique signature: large missing transverse energy and the low-charged-multiplicity tau. Data collected in the period 1992-1993 at the Collider Detector at Fermilab, corresponding to 18.7$\pm$0.7~pb$^{-1}$, exclude new regions of combined top quark and charged Higgs mass, in extensions to the standard model with two Higgs doublets.Comment: uuencoded, gzipped tar file of LaTeX and 6 Postscript figures; 11 pp; submitted to Phys. Rev.

Inclusive jet cross section in pˉp{\bar p p} collisions at s=1.8\sqrt{s}=1.8 TeV

The inclusive jet differential cross section has been measured for jet transverse energies, $E_T$, from 15 to 440 GeV, in the pseudorapidity region 0.1$\leq | \eta| \leq$0.7. The results are based on 19.5 pb$^{-1}$ of data collected by the CDF collaboration at the Fermilab Tevatron collider. The data are compared with QCD predictions for various sets of parton distribution functions. The cross section for jets with $E_T>200$ GeV is significantly higher than current predictions based on O($\alpha_s^3$) perturbative QCD calculations. Various possible explanations for the high-$E_T$ excess are discussed.Comment: 8 pages with 2 eps uu-encoded figures Submitted to Physical Review Letter

Measurement of the top quark mass and top-antitop production cross section from dilepton events at the Collider Detector at Fermilab

We present an analysis of dilepton events originating from top-antitop production in proton-antiproton collisions at sqrt{s}=1.8 TeV at the Fermilab Tevatron Collider. The sample corresponds to an integrated luminosity of 109+-7 pb^{-1}. We observe 9 candidate events, with an estimated background of 2.4+-0.5 events. We determine the mass of the top quark to be M_top = 161+-17(stat.)+-10(syst.) GeV/c^2. In addition we measure a top-antitop production cross section of 8.2+4.4-3.4 pb (where M_top = 175 GeV/c^2 has been assumed for the acceptance estimate).Comment: 6 pages of text, 3 figure

Search for Chargino-Neutralino Associated Production at the Fermilab Tevatron Collider

We have searched in $p \bar{p}$ collisions at $\sqrt{s}$ = 1.8 TeV for events with three charged leptons and missing transverse energy. In the Minimal Supersymmetric Standard Model, we expect trilepton events from chargino-neutralino (\chione \chitwo) pair production, with subsequent decay into leptons. We observe no candidate $e^+e^-e^\pm$, $e^+e^-\mu^\pm$, $e^\pm\mu^+\mu^-$ or $\mu^+\mu^-\mu^\pm$ events in 106 pb$^{-1}$ integrated luminosity. We present limits on the sum of the branching ratios times cross section for the four channels: \sigma_{\chione\chitwo}\cdot BR(\chione\chitwo\to 3\ell+X) 81.5 \mgev\sp and M_\chitwo > 82.2 \mgev\sp for $\tan\beta=2$, $\mu =-600$~\mgev\sp and M_\squark= M_\gluino.Comment: 9 pages and 3 figure