977 resultados para Contingent or bouligand derivative
Resumo:
A partially occluded contour and a slanted contour may generate identical binocular horizontal disparities. We investigated conditions promoting an occlusion resolution indicated by an illusory contour in depth along the aligned ends of horizontally disparate line sets. For a set of identical oblique lines with a constant width added to one eye's view, strength, depth, and stability of the illusory contour were poor, whereas for oblique lines of alternating orientations the illusory contours were strong, indicating a reliance on vertical size disparities rather than vertical positional disparities in generating perceived occlusion. For horizontal lines, occlusion was seen when the lines were of different lengths and absolute width disparity was invariant across the set. In all line configurations, when the additional length was on the wrong eye to be attributed to differential occlusion, lines appeared slanted consistent with their individual horizontal disparities. This rules out monocular illusory contours as the determining factor.
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Objectives This study was designed to evaluate whether the absence of coronary calcium could rule out >= 50% coronary stenosis or the need for revascularization. Background The latest American Heart Association guidelines suggest that a calcium score (CS) of zero might exclude the need for coronary angiography among symptomatic patients. Methods A substudy was made of the CORE64 (Coronary Evaluation Using Multi-Detector Spiral Computed Tomography Angiography Using 64 Detectors) multicenter trial comparing the diagnostic performance of 64-detector computed tomography to conventional angiography. Patients clinically referred for conventional angiography were asked to undergo a CS scan up to 30 days before. Results In all, 291 patients were included, of whom 214 (73%) were male, and the mean age was 59.3 +/- 10.0 years. A total of 14 (5%) patients had low, 218 (75%) had intermediate, and 59 (20%) had high pre-test probability of obstructive coronary artery disease. The overall prevalence of >= 50% stenosis was 56%. A total of 72 patients had CS = 0, among whom 14 (19%) had at least 1 >= 50% stenosis. The overall sensitivity for CS = 0 to predict the absence of >= 50% stenosis was 45%, specificity was 91%, negative predictive value was 68%, and positive predictive value was 81%. Additionally, revascularization was performed in 9 (12.5%) CS = 0 patients within 30 days of the CS. From a total of 383 vessels without any coronary calcification, 47 (12%) presented with >= 50% stenosis; and from a total of 64 totally occluded vessels, 13 (20%) had no calcium. Conclusions The absence of coronary calcification does not exclude obstructive stenosis or the need for revascularization among patients with high enough suspicion of coronary artery disease to be referred for coronary angiography, in contrast with the published recommendations. Total coronary occlusion frequently occurs in the absence of any detectable calcification. (Coronary Evaluation Using Multi-Detector Spiral Computed Tomography Angiography Using 64 Detectors [CORE-64]; NCT00738218) (J Am Coll Cardiol 2010;55:627-34) (C) 2010 by the American College of Cardiology Foundation
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Objectives: We tested two novel drug-eluting stents (DES), covered with a biodegradable-polymer carrier and releasing paclitaxel or sirolimus, which were compared against a bare metal stent (primary objective). The DES differed by the drug, but were identical otherwise, allowing to compare the anti-restenosis effects of sirolimus versus paclitaxel (secondary objective). Background: The efficacy of novel DES with biodegradable polymers should be tested in the context of randomized trials, even when using drugs known to be effective, such as sirolimus and paclitaxel. Methods: Overall, 274 patients with de novo coronary lesions in native vessels scheduled for stent implantation were randomly assigned (2:21 ratio) for the paclitaxel (n = 111), sirolimus (n = 106), or bare metal stent (n = 57) groups. Angiographic follow-up was obtained at 9 months and major cardiac adverse events up to 12 months. Results: Both paclitaxel and sirolimus stents reduced the 9-month in-stent late loss (0.54-0.44 mm, 0.32-0.43 mm, vs. 0.90-0.45 mm respectively), and 1-year risk of target vessel revascularization and combined major adverse cardiac events (P < 0.05 for both, in all comparisons), compared with controls. Sirolimus stents had lower late loss than paclitaxel stents (P < 0.01), but similar 1-year clinical outcomes. There were no differences in the risk of death, infarction, or stent thrombosis among the study groups. Conclusion: Both novel DES were effective in reducing neointimal hyperplasia and 1-year re-intervention, compared to bare metal stents. Our findings also suggest that sirolimus is more effective than paclitaxel in reducing angiographic neointima, although this effect was not associated with better clinical outcomes. (C) 2009 Wiley-Liss, Inc.
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Fire ephemerals are short-lived plants that primarily germinate after fire. Fresh and laboratory-stored seeds are difficult to germinate ex situ, even in response to fire-related cues such as heat and smoke. Seeds of eight Australian fire ephemeral species were buried in unburnt and recently burnt sites of natural bushland during autumn. Seeds were exhumed after 6 and 12 months and incubated in water and smoke water, either with or without a heat treatment at 70 degrees C for 1 h. Generally, germination did not increase after 6 months of burial, but after 12 months of burial germination was enhanced in seven of the eight species. Actinotus leucocephalus produced higher germination following 12 months of burial without any further treatment, and smoke water and heat further improved germination. The four Gyrostemonaceae species, Codonocarpus cotinifolius, Gyrostemon racemiger, Gyrostemon ramulosus and Tersonia cyathiflora, only germinated in the presence of smoke water, and their germination was enhanced by burial. Burial improved germination in response to a heat treatment in Grevillea scapigera and Alyogyne huegelii seeds, but did not enhance Alyogyne hakeifolia germination. During concurrent dry laboratory storage of seeds at 15 degrees C, only Actinotus leucocephalus produced increased germination in response to smoke water and heat over time. In summary, soil burial can alter the dormancy status of a number of Australian fire ephemeral seeds, rendering them more responsive to germination cues such as smoke water and heat. The requirement for a period of burial before seeds become responsive to smoke and/or heat would ensure that seeds persist in the soil until a subsequent fire, when there is an increase in nutrients available for growth and reduced competition from other plants.
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In the present study, we analyzed how high-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor hand area (M1-Hand) shapes anticipatory motor activity in frontal areas as indexed by the contingent negative variation (CNV). Eight right-handed volunteers received real or sham 5 Hz rTMS at an intensity of 90% resting motorthreshold (1500 stimuli per session). Real but not sham rTMS to left M1-Hand induced a site-specific increase in amplitude of the late component of the CNV at the electrode C3 overlaying the site of stimulation. The increase in pre-movement activity in the stimulated cortex may reflect an increase in facilitatory drive from connected motor areas, enhanced responsiveness of the stimulated cortex to these inputs or both. (c) 2005 Elsevier Ireland Ltd. All rights reserved.
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Although a new protocol of dobutamine stress echocardiography with the early injection of atropine (EA-DSE) has been demonstrated to be useful in reducing adverse effects and increasing the number of effective tests and to have similar accuracy for detecting coronary artery disease (CAD) compared with conventional protocols, no data exist regarding its ability to predict long-term events. The aim of this study was to determine the prognostic value of EA-DSE and the effects of the long-term use of beta blockers on it. A retrospective evaluation of 844 patients who underwent EA-DSE for known or suspected CAD was performed; 309 (37%) were receiving beta blockers. During a median follow-up period of 24 months, 102 events (12%) occurred. On univariate analysis, predictors of events were the ejection fraction (p <0.001), male gender (p <0.001), previous myocardial infarction (p <0.001), angiotensin-converting enzyme inhibitor therapy (p = 0.021), calcium channel blocker therapy (p = 0.034), and abnormal results on EA-DSE (p <0.001). On multivariate analysis, the independent predictors of events were male gender (relative risk [RR] 1.78, 95% confidence interval [CI] 1.13 to 2.81, p = 0.013) and abnormal results on EA-DSE (RR 4.45, 95% CI 2.84 to 7.01, p <0.0001). Normal results on EA-DSE with P blockers were associated with a nonsignificant higher incidence of events than normal results on EA-DSE without beta blockers (RR 1.29, 95% CI 0.58 to 2.87, p = 0.54). Abnormal results on EA-DSE with beta blockers had an RR of 4.97 (95% CI 2.79 to 8.87, p <0.001) compared with normal results, while abnormal results on EA-DSE without beta blockers had an RR of 5.96 (95% CI 3.41 to 10.44, p <0.001) for events, with no difference between groups (p = 0.36). In conclusion, the detection of fixed or inducible wall motion abnormalities during EA-DSE was an independent predictor of long-term events in patients with known or suspected CAD. The prognostic value of EA-DSE was not affected by the long-term use of beta blockers. (C) 2008 Elsevier Inc. All rights reserved. (Am J Cardiol 2008;102:1291-1295)
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Background and purpose: To evaluate biochemical control and treatment related toxicity of patients with localized adenocarcinoma of the prostate treated with high dose-rate brachytherapy (HDRB) combined with conventional 2D or 3D-conformal external beam irradiation (EBI). Material and methods: Four-hundred and three patients treated between December 2000 and March 2004. HDRB was delivered with three fractions of 5.5-7 Gy with a single implant, followed by 45 Gy delivered with 2D or 3D conformal EBI. Results: The median follow-up was 48.4 months. Biochemical failure (BF) occurred in 9.6% according to both ASTRO and Phoenix consensus criteria. Mean time to relapse was 13 and 26 months, respectively. The 5-year BF free survival using the ASTRO criteria was 94.3%, 86.9% and 86.6% for the low, intermediate and high risk groups, respectively; using Phoenix criteria, 92.4%, 88.0% and 85.3%, respectively. The only predictive factor of BF in the multivariate analysis by both ASTRO and Phoenix criteria was the presence of prostate nodules detected by digital palpation, and patients younger than 60 years presented a higher chance of failure using Phoenix criteria only. Conclusions: Treatment scheme is feasible and safe with good efficacy. (C) 2011 Elsevier Ireland Ltd All rights reserved. Radiotherapy and Oncology 98 (2011) 169-174
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Purpose: To evaluate the influence of cross-sectional arc calcification on the diagnostic accuracy of computed tomography (CT) angiography compared with conventional coronary angiography for the detection of obstructive coronary artery disease (CAD). Materials and Methods: Institutional Review Board approval and written informed consent were obtained from all centers and participants for this HIPAA-compliant study. Overall, 4511 segments from 371 symptomatic patients (279 men, 92 women; median age, 61 years [interquartile range, 53-67 years]) with clinical suspicion of CAD from the CORE-64 multi-center study were included in the analysis. Two independent blinded observers evaluated the percentage of diameter stenosis and the circumferential extent of calcium (arc calcium). The accuracy of quantitative multidetector CT angiography to depict substantial (>50%) stenoses was assessed by using quantitative coronary angiography (QCA). Cross-sectional arc calcium was rated on a segment level as follows: noncalcified or mild (<90 degrees), moderate (90 degrees-180 degrees), or severe (>180 degrees) calcification. Univariable and multivariable logistic regression, receiver operation characteristic curve, and clustering methods were used for statistical analyses. Results: A total of 1099 segments had mild calcification, 503 had moderate calcification, 338 had severe calcification, and 2571 segments were noncalcified. Calcified segments were highly associated (P < .001) with disagreement between CTA and QCA in multivariable analysis after controlling for sex, age, heart rate, and image quality. The prevalence of CAD was 5.4% in noncalcified segments, 15.0% in mildly calcified segments, 27.0% in moderately calcified segments, and 43.0% in severely calcified segments. A significant difference was found in area under the receiver operating characteristic curves (noncalcified: 0.86, mildly calcified: 0.85, moderately calcified: 0.82, severely calcified: 0.81; P < .05). Conclusion: In a symptomatic patient population, segment-based coronary artery calcification significantly decreased agreement between multidetector CT angiography and QCA to detect a coronary stenosis of at least 50%.
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PURPOSE To compare reading ability after cataract surgery and bilateral implantation of multifocal intraocular lenses (IOLs) with a +3 00 diopter (D) addition (add) or a +4 00 D add SETTING Department of Ophthalmology, University of Sao Paulo, Sao Paulo, Brazil DESIGN Prospective comparative study METHODS Patients scheduled for cataract surgery were randomly assigned to bilateral implantation of an aspheric AcrySof ReSTOR multifocal IOL with a +3 00 diopter (D) addition (add) or a +4 00 D add The reading speed, critical print size, and reading acuity were measured binocularly with best correction using MNREAD acuity charts 6 months after surgery Patients were tested with the chart at the best patient-preferred reading distance and at 40 cm Binocular uncorrected and best distance-corrected visual acuities at far and near were also measured RESULTS The study enrolled 32 patients At the best reading distance the results were similar between the 2 IOL groups in all reading parameters When tested at 40 cm, reading speed at all print sizes from 03 to 00 (all P< 001), critical print size (P< 001) and reading acuity (P = 014) were statistically significantly better in the +3 00 D IOL group than in the +4 00 DIOL group Uncorrected and corrected visual acuities at far and near were similar between the 2 groups CONCLUSION Although the 2 IOL groups had similar performance in reading parameters, patients had to adjust to their best reading distance The +3 00 D IOL performed better than the +4 00 D IOL at 40 cm