ODP Leg 198 drilling on Shatsky Rise recovered a lower Aptian porcellanite (~120.5 Ma) deposited during oceanic anoxic event (OAE) 1a that contains C sub(36)-C sub(39) alkadienones: C sub(37:2) and C ...sub(39:2) alkadien-2-ones and C sub(36:2) and C sub(38:2) alkadien-3-ones. This alkenone distribution differs from that typical of contemporary sediments and haptophyte algae, but resembles that of Cretaceous sediments from the Blake-Bahama basin. The discovery of alkenones in the early Aptian extends their sedimentary record by 15 M.y. to 120.5 M.y. and demonstrates the potential for long-term survival of these diagnostic functional lipids under favorable depositional conditions and subsequent shallow burial. It also contributes to the understanding and reconstruction of evolutionary developments in alkenone distributions and biosynthesis over geologic time.
Canada's June 28th, 2004, federal election was an exciting and, in several respects a surprising contest. One major surprise was the election campaign itself. Rather than being the predictable, ...boring event many commentators had anticipated, the campaign was a closely fought battle between a longtime governing party and a new opposition party that had been formed only six months before the election was called. A second surprise, at least for some observers, was turnout, with participation in a national election falling to the lowest level in Canadian history. A third, potentially very significant, surprise was the success of the separatist Bloc Québécois, accompanied by a resurgence of support for Quebec sovereignty. After the election, the future of Canada's national party system, indeed, the future of Canadian democracy, appeared more problematic than had been the case only a few months earlier.
The measurement of small–angle Bhabha scattering is used to determine the luminosity at the OPAL interaction point for the LEP I data recorded between 1993 and 1995. The measurement is based on the ...OPAL Silicon-Tungsten Luminometer which is composed of two calorimeters encircling the LEP beam pipe, on opposite sides of the interaction point. The luminometer detects electrons from small–angle Bhabha scattering at angles between 25 and 58 mrad. At LEP center-of-mass energies around the Z\(^0\), about half of all Bhabha electrons entering the detector fall within a 79 nb fiducial acceptance region. The electromagnetic showers generated in the stack of 1 radiation length tungsten absorber plates are sampled by 608 silicon detectors with 38,912 radial pads of 2.5 mm width. The fine segmentation of the detector, combined with the precise knowledge of its physical dimensions, allows the trajectories of incoming 45 GeV electrons or photons to be determined with a total systematic error of less than 7 microns. We have quantified all significant sources of systematic experimental error in the luminosity determination by direct physical measurement. All measured properites of the luminosity event sample are found to be in agreement with current theoretical expectations. The total systematic measurement uncertainty is \(3.4 \times 10^{-4}\), significantly below the theoretical error of \(5.4 \times 10^{-4}\) currently assigned to the QED calculation of the Bhabha acceptance, and contributes negligibly to the total uncertainty in the OPAL measurement of \(\Gamma_{\rm inv}/ \Gamma_{\ell^+\ell^-}\), a quantity of basic physical interest which depends crucially on the luminosity measurement.
We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au+Au collisions at sNN=200 GeV using the STAR ...detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage −1.3,1.3. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes.
Objectives. To prospectively evaluate a clinical algorithm that predicts nodal status in patients with prostate cancer and to assess the impact on the outcome.
Methods. Between September 1988 and ...December 1994, 192 patients with organ-confined prostate cancer and considered surgical candidates for radical perineal prostatectomy (RPP) were stratified using the algorithm: prostate-specific antigen (PSA) 20 ng/mL or less, Gleason score 7 or lower, and clinical Stage T2a or lower. Patients failing any of these criteria were placed in the high-risk group and underwent a pelvic lymphadenectomy. Patients who satisfied all the criteria were placed in the low-risk group and underwent RPP without evaluation of the pelvic lymph nodes. Another contemporaneous cohort of patients (n = 65) underwent pelvic lymphadenectomy and radical retropubic prostatectomy (RRP) without use of the algorithm and were used as a control group. Patients were monitored for at least 24 months.
Results. In the RPP group, 177 patients were considered low risk according to the algorithm and were not offered staging lymphadenectomy before surgery, whereas 15 patients were categorized as high risk for metastasis and underwent staging lymphadenectomy. In the RRP and lymphadenectomy group, 41 patients were considered at low risk and 24 at high risk of disease spread according to the algorithm. In the RPP group, low-risk patients (no lymphadenectomy) had a PSA recurrence rate (27%) similar to that of low-risk patients in the RRP group with negative lymph nodes (29%),
P = 0.8. Similarly, high-risk patients with negative lymph nodes in both groups had a similar recurrence rate (53% for RPP and 50% for RRP). Univariate logistic regression analysis showed that PSA was the most significant predictor for disease recurrence (
P = 0.0004) followed by preoperative Gleason scores (
P = 0.02) and clinical stages (
P = 0.03). Multivariate stepwise analysis demonstrated that Gleason score and clinical stage did not add to the prediction of recurrence over PSA alone.
Conclusions. Staging lymphadenectomy can be omitted in low-risk patients without deleterious effects on the outcome as measured by PSA recurrence.
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