ABSTRACT
Bottom-quark production in &pmacr;p collisions at sqrt[s] = 1.8 TeV is studied with 5 pb(-1) of data collected in 1995 by the D0 detector at the Fermilab Tevatron Collider. The differential production cross section for b jets in the central rapidity region ( | y(b)|<1) as a function of jet transverse energy is extracted from a muon-tagged jet sample. Within experimental and theoretical uncertainties, D0 results are found to be higher than, but compatible with, next-to-leading-order QCD predictions.
ABSTRACT
We present a measurement of the transverse momentum distribution of Z bosons produced in p&pmacr; collisions at sqrt[s] = 1.8 TeV from data collected by the DO experiment at the Fermilab Tevatron Collider. We find good agreement between our results and current resummation calculations, and also use our data to extract nonperturbative parameters for a particular version of the resummation formalism. The resulting values are significantly more precise than obtained in previous determinations.
ABSTRACT
This Letter describes a measurement of the muon cross section originating from b-quark decay in the forward rapidity range 2.4<| y(&mgr;)|<3.2 in p&pmacr; collisions at sqrt[s] = 1.8 TeV. The data used in this analysis were collected by the D0 experiment at the Fermilab Tevatron. We find that next-to-leading-order QCD calculations underestimate b-quark production by a factor of 4 in the forward rapidity region.
ABSTRACT
Objective: To determine the risk factors associated with blood transfusion in ectopic pregnancy.Methods: A retrospective chart review of the presentation and hospital course of ectopic pregnancies managed over 5 years at two hospitals was undertaken. Thirty-two variables, including demographics, presenting signs and symptoms, and intraoperative findings, were examined in univariate and multivariate logistic modeling.Results: Among 185 patients with histologically confirmed ectopic pregnancies who were managed surgically, 8.6% or 16 women required transfusion. Multivariate analysis of risk factors for blood transfusion demonstrated a statistically significant association with 1) initial hemoglobin <10 g/dL (odds ratio [OR] 38.8, 95% confidence interval [CI] 6.0-356.8) and 2) hCG levels >/= 6500 mIU (OR 18.1, 95% CI 3.6-158.1), as well as 3) abnormal bleeding on presentation (OR 0.08, 95% CI 0.007-0.42. Presence of two of these factors has a sensitivity of 82% (95% CI 48-98%) and a positive predictive value of 33% (95% CI 16-54%). No case had all three factors present.Conclusion: This report is, to our knowledge, the first regression analysis of risk factors for transfusion associated with ectopic pregnancy. It demonstrates that initial hemoglobin and hCG levels as well as abnormal bleeding on presentation are independent risk factors for blood transfusion in ectopic pregnancy.
