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C N Brown

Publications and source records attributed to C N Brown.

11 recordsLinked to original sources
PubMed2003

J/psi polarization in 800-GeV p-Cu interactions.

We present measurements of the polarization of the J/psi produced in 800-GeV proton interactions with a copper target. Polarization of the J/psi is sensitive to the ccmacr; production and hadronization processes. A longitudinal polarization is observed at large x(F), while at small x(F) the state is produced essentially unpolarized or slightly transversely polarized. No significant variation of the polarization is observed versus p(T).

Journal Article↗
PubMed2003

Effects of prolonged reduction in blood flow on submandibular secretory function in anesthetized sheep.

Submandibular vascular and secretory responses to parasympathetic chorda-lingual (C-L) stimulation were investigated in anesthetized sheep before, during, and after an intracarotid (ic) infusion of endothelin-1 (ET-1). Stimulation of the peripheral end of the C-L nerve at 4 and 8 Hz produced a frequency-dependent reduction in submandibular vascular resistance (SVR) associated with a frequency-dependent increase in submandibular blood flow, salivary flow, and Na+, K+, and protein output from the gland. During stimulation at 4 Hz, ic ET-1 significantly increased SVR (P < 0.01), without significantly affecting either the aortic blood pressure or heart rate. Submandibular blood flow (SBF) was reduced by 48 +/- 4% and the flow of saliva by 50 +/- 1%. The effect on blood and salivary flow persisted for at least 30 min after the infusion of ET-1. The reduction in SBF was associated with a diminution in the output of Na+,K+, and protein in the saliva (P < 0.01). These effects persisted for 30 min after the infusion of ET-1 had been discontinued and were linearly related to the flow of plasma throughout.

Animals↗
PubMed2001

Energy loss of fast quarks in nuclei.

We report an analysis of the nuclear dependence of the yield of Drell-Yan dimuons from the 800 GeV/c proton bombardment of 2H, C, Ca, Fe, and W targets. Employing a new formulation of the Drell-Yan process in the rest frame of the nucleus, this analysis examines the effect of initial-state energy loss and shadowing on the nuclear-dependence ratios versus the incident proton's momentum fraction and dimuon effective mass. The resulting energy loss per unit path length is -dE/dz = 2.32+/-0.52+/-0.5 GeV/fm. This is the first observation of a nonzero energy loss of partons traveling in a nuclear environment.

Journal Article↗
PubMed2001

Observation of polarization in bottomonium production at square root of s = 38.8 GeV.

We present a measurement of the polarization observed for bottomonium states produced in p-Cu collisions at square root of s = 38.8 GeV. The angular distribution of the decay dimuons of the Upsilon(1S) state shows no polarization at small values of the fractional longitudinal momentum x(F) and transverse momentum p(T) but significant positive transverse production polarization for either p(T)>1.8 GeV/c or for x(F)>0.35. The Upsilon(2S+3S) (unresolved) states show a large transverse production polarization at all values of x(F) and p(T) measured. These observations challenge NRQCD calculations of the polarization expected in the hadronic production of bottomonium states.

Journal Article↗
PubMed1982

Identification of transient and persistent segmental wall motion abnormalities in patients with unstable angina by two-dimensional echocardiography.

To determine the value of real-time, two-dimensional echocardiography (2-D echo) in unstable angina, regional wall motion on serial short-axis 2-D echo recordings was analyzed and summed segment scores of abnormal motion were compared and classified according to each patient's clinical status 12 weeks after hospital discharge. Nineteen male patients who fulfilled criteria for unstable angina and responded to medical therapy underwent 2-D echo study within 48 hours of admission and discharge. Of 11 patients with abnormal 2-D echo scores on admission, five patients had reduced scores and six patients had similar or increased scores at discharge. Six of eight patients who had scores of zero on admission had scores of zero at discharge. At follow-up, 11 patients had minimal or no angina pectoris (group 1), and eight patients had worsening angina or recurrent unstable angina (group 2). At discharge, 2-D echo studies showed that all group 1 patients had reduced or zero scores, while group 2 patients retained or increased their abnormal scores. This study shows that in patients with unstable angina, both transient and persistent abnormalities can be identified by 2-D echo. Abnormal segmental wall motion was transient or absent in patients with a good outcome, and worsened or remained abnormal in patients with a poor outcome.

Aged↗