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51.
Sausen Kenneth P.; Lovallo William R.; Pincomb Gwendolyn A.; Wilson Michael F. 《Canadian Metallurgical Quarterly》1992,11(1):55
Examined hemodynamic responses to systematic variations in occupational stress using ambulatory blood pressure monitors. Heart rate, systolic blood pressure, diastolic blood pressure, rate–pressure product, and mood states were measured before, during, and after low-stress (lecture) and high-stress (examination) work in 44 healthy White male medical students. The lecture day was characterized by stable patterns of cardiovascular activity across all 3 periods. Hemodynamic activity and reports of activation and distress were greater on the examination day than on the lecture day. Cardiovascular activity during the pre-examination period was as high as that seen during the examination period itself, indicating an anticipatory stress effect. Pressor activity decreased after the examination, although some residual chronotropic activity was seen. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
52.
Simon P. Wilson Francisco J. Samaniego 《IEEE transactions on pattern analysis and machine intelligence》2007,33(3):198-208
In the literature on statistical inference in software reliability, the assumptions of parametric models and random sampling of bugs have been pervasive. We argue that both assumptions are problematic, the first because of robustness concerns and the second due to logical and practical difficulties. These considerations motivate the approach taken in this paper. We propose a nonparametric software reliability model based on the order-statistic paradigm. The objective of the work is to estimate, from data on discovery times observed within a type I censoring framework, both the underlying distribution F from which discovery times are generated and N, the unknown number of bugs in the software. The estimates are used to predict the next time to failure. The approach makes use of Bayesian nonparametric inference methods, in particular, the beta-Stacy process. The proposed methodology is illustrated on both real and simulated data 相似文献
53.
54.
Piers Wilson 《Network Security》2003,2003(8):16-18
Rogue servers are a constant threat and pose a variety of problems for the IT security team. This article summarises the threats that come from not managing rogue servers and gives prevention and detection tips. 相似文献
55.
56.
Serum lipids and incidence of coronary heart disease. Findings from the Systolic Hypertension in the Elderly Program (SHEP) 总被引:3,自引:0,他引:3
PH Frost BR Davis AJ Burlando JD Curb GP Guthrie JL Isaacsohn S Wassertheil-Smoller AC Wilson J Stamler 《Canadian Metallurgical Quarterly》1996,94(10):2381-2388
BACKGROUND: The association of serum lipids with coronary heart disease has been studied extensively in middle-aged men and, to a lesser extent, in similar women. Less well defined are lipid variables predictive of CHD in individuals of age > or = 60 years. METHODS AND RESULTS: The Systolic Hypertension in the Elderly Program recruited 4736 persons (mean age, 72 years; 14% were black; and 43% were men). Mean systolic and diastolic blood pressures were 170 and 77 mm Hg, respectively. Baseline mean total cholesterol was 6.11 mmol/L (236 mg/dL); HDL cholesterol, 1.39 mmol/L (54 mg/dL); and non-HDL cholesterol, 4.72 mmol/L (182 mg/dL). Triglyceride levels were 1.62 mmol/L (144 mg/dL) for fasting participants and 1.78 mmol/L for the total group. LDL cholesterol, estimated in fasting samples with triglycerides of < 4.52 mmol/L, averaged 3.98 mmol/L (154 mg/dL). Mean follow-up was 4.5 years. In multivariate Cox regression analyses, baseline total, non-HDL, and LDL cholesterol levels and the ratios of total, non-HDL, and LDL to HDL cholesterol were significantly related to CHD incidence. HDL cholesterol and triglycerides were not significant in these analyses. In fasting participants with triglyceride levels of < 4.52 mmol/L, a 1.03 mmol/L (40 mg/dL) higher baseline total, non-HDL, or LDL cholesterol was associated with a 30% to 35% higher CHD event rate. CONCLUSIONS: The results of this study support the concept that serum lipids are CHD risk factors in older Americans. 相似文献
57.
The biological consequences of O6-methylguanine (m6G) in DNA are well recognized. When template m6G is encountered by DNA polymerases, replication is hindered and trans-lesion replication results in the preferential incorporation of dTMP opposite template m6G. Thus, unrepaired m6G in DNA is both cytotoxic and mutagenic. Yet, cell lines tolerant to m6G in DNA have been isolated, which indicates that some cellular DNA polymerases may replicate m6G-containing DNA with reasonable efficiency. Previous reports suggested that mammalian pol beta could not replicate m6G-containing DNA, but we find that pol beta can catalyze trans-lesion replication; however, the lesion must reside in the optimal context for pol beta activity, single- or short nucleotide gapped substrates. Primed single-stranded DNA templates, with or without template m6G, were poor substrates for pol beta as reported in earlier studies. In contrast, trans-lesion replication by bacteriophage T4 DNA polymerase was observed for primed single-stranded DNA templates. Replication of m6G-containing DNA by T4 DNA polymerase required the gp45 accessory protein that clamps the polymerase to the DNA template. The rate-limiting step in replicating m6G-containing DNAs by both DNA polymerases tested was incorporation of dTMP across from the lesion. 相似文献
58.
Wilson B.C. Sevick E.M. Patterson M.S. Chance B. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1992,80(6):918-930
The application of optical spectroscopy and imaging in living tissue is complicated by multiple scattering of light. In spectroscopy, this scattering causes uncertainty in the pathlength traveled by photons in the tissue, while images suffer reduced resolution and contrast. Picosecond light sources and fast detectors have made it possible to address these problems by direct measurement of the photon time-of-flight. Diffusion models of light propagation can be used to relate the measured distribution of photon transit times to the scattering and absorption coefficients of the tissue. The advantages of absolute absorption measurement are demonstrated for two problems: determination of hemoglobin oxygenation in tissue and in vivo measurement of the uptake of an exogenous chromosphere such as photosensitizer. Optical imaging may also be improved by the elimination of multiply scattered photons or by selective detection of photons arriving from a given region of the tissue. The potential advantages of these techniques are discussed and illustrated with experimental data 相似文献
59.
A Mitchener DJ Wyper J Patterson DM Hadley JT Wilson LC Scott M Jones GM Teasdale 《Canadian Metallurgical Quarterly》1997,62(6):633-636
We report a case of cervicofacial necrotizing fasciitis that developed after blepharoplasty, an occurrence that, to our knowledge, has not previously been reported in the medical literature. A patient who presented to our institution 3 days after undergoing blepharoplasty of the upper eyelid was diagnosed as having fulminant fasciitis involving extensive areas of the face, scalp, and neck. We review the case in detail and discuss clinical and radiological clues to diagnosis, surgical and medical management, wound care, and subsequent scar contracture. This case emphasizes the need for individualized, appropriate postoperative care and for an awareness of this rare, potentially fatal complication. Early recognition and aggressive treatment of cervicofacial fasciitis can arrest its rapid progression and prevent devastating sequelae. 相似文献
60.
IA Wilson RL Stanfield DA Jewell JB Ghiara DH Fremont EA Stura 《Canadian Metallurgical Quarterly》1994,3(2-3):155-162
The response exhibited by the immune system to viral and other foreign antigens consists of antibody-mediated and T cell-mediated immunity. Structural and molecular biological studies have shown that the antibody response is tailored to provide exquisite specificity by generating binding pockets that are complementary in shape as well as in charge to the antigen. On the other hand, the cellular response uses T-cell receptors (TCRs) and the major histocompatibility complex (MHC) antigens. Structural information on the TCRs is not yet available, but the crystal structures of several MHC class I molecules have shown how one MHC molecule can bind many different peptide sequences that share only the common anchor residue positions that determine allele specificity. MHC class I interactions with the peptide backbone at the N and C termini explain the high specificity of the binding groove for peptide ligands and suggest a universal mode of recognition for peptides to MHC class I molecules. Peptide-MHC class II interactions are less well understood, although recent structural work has shown important differences in the binding clefts of MHC class I and II that lead to longer peptides being bound to class II molecules. Detailed analysis at the molecular level has indicated that conformational changes in both antibodies and MHC molecules occur upon antigen binding.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献