15 resultados para ellipse

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Purpose: Several urethral conditions may require tissue substitution. One collagen-base biomaterial that recently emerged as an option is small intestinal submucosa (SIS). The aim of this study was to compare the results of SIS and buccal mucosa for urethral substitution in rabbits.Materials and Methods: Thirty-six North Folk male rabbits were randomized into three groups. In all animals, a 10 x 5 mm urethral segment was excised, and the urethral defect was repaired using a one-layer SIS patch (group I [GI]); four-layer SIS (group II [GII]); or buccal mucosa (group III [GIII]). Urethrography was performed preoperatively and after 12 weeks. After sacrifice, graft retraction was objectively measured using Scion Image (R) computer analysis and by calculation of ellipse area. The grade of fibrosis, inflammatory reaction, vascular/epithelial regeneration, and collagen III/I ratio were analyzed by hematoxylin/eosin and Picrosirius red staining.Results: Urethrography confirmed a wide urethral caliber without any signs of strictures after surgery. Urethral fistulae was diagnosed in 8.3% of cases (1 animal each group). Average graft shrinkage was 55.2% in GI; 44.2% in GII; and 57.2% in GIII (p < 0.05). The intensity of chronic inflammation, fibrosis, epithelium regeneration, and neovascularization was similar in all groups (p > 0.05). Collagen III/I ratio was higher in GII (GI: 119.6; GII: 257.2 and GIII: 115.0); p < 0.01.Conclusions: The four-layer SIS is more advantageous than the one-layer SIS and buccal mucosa for urethral substitution in rabbits.

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Recently the CP trajectory diagram was introduced to demonstrate the difference between the intrinsic CP violating effects to those induced by matter for neutrino oscillation. In this Letter we introduce the T trajectory diagram. In these diagrams the probability for a given oscillation process is plotted versus the probability for the CP- or the T-conjugate processes, which forms an ellipse as the CP- or T-violating phase is varied. Since the CP- and the T-conjugate processes are related by CPT symmetry, even in the presence of matter, these two trajectory diagrams are closely related with each other and form a unified description of neutrino oscillations in matter. (C) 2002 Published by Elsevier B.V. B.V.

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Stationary states of an electron in thin GaAs elliptical quantum rings are calculated within the effective-mass approximation. The width of the ring varies smoothly along the centerline, which is an ellipse. The solutions of the Schrödinger equation with Dirichlet boundary conditions are approximated by a product of longitudinal and transversal wave functions. The ground-state probability density shows peaks: (i) where the curvature is larger in a constant-with ring, and (ii) in thicker parts of a circular ring. For rings of typical dimensions, it is shown that the effects of a varying width may be stronger than those of the varying curvature. Also, a width profile which compensates the main localization effects of the varying curvature is obtained.

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The sedimentary Curitiba basin is located in the Central-Southern part of the first Parananense plateau, and comprises Curitiba (PR), and part of the neighbour Municipalities (fig.1). It is supposed to be of Plio-Pleistocene age. It has a shallow sedimentary fulfillment, represented by the Guabirotuba formation (BIGARELLA and SALAMUNI, 1962) which is dristributed over a large area of about 3.000km2. The internal geometry, not entirely known yet, is actually object of detailed research, that shows its geological evolution to Cenozoic tectonic movements. For the purpose of this study the definition of the structural contour of the basement and their depo-centers is fundamental. This paper presents the results of the integration of surface and subsurface data, processed by statistical methods, which allowed a more precise definition of the morphostructural framework of the basement. For the analysis of the geological spacial data, specific softwares were used for statistical processing for trend surfaces analysis. The data used in this study are of following types: a) drilling logs for ground water; b) description of surface points of geological maps (CRPM, 1977); c) description of points of geotechnical drillings and down geological survey. The data of 223 drilling logs for ground water were selected out of 770 wells. The description files of 700 outcrops, as well as planialtimetric field data, were used for the localization of the basement outcrop. Thus, a matrix with five columns was set up: utm E-W (x) and utm N-S (y); surface altitude (z); altimetric cote of the contact between sedimentary rocks and the basement (k); isopachs (l). For the study of the basement limits, the analysis of surface trends of 2(nd) and 3(rd) degree polinomial for the altimetric data (figs. 2 and 3) were used. For the residuals the method of the inverse of the square of the distance (fig.4) was used. The adjustments and the explanations of the surfaces were made with the aid of multiple linear regressions. The analysis of 3rd degree polinomial trend surface (fig.3) confirmed that the basement tends to be more exposed towards NNW-SSE explaining better the data trend through an ellipse, which striking NE-SW and dipping SW axis coincides with the trough of the basin observed in the trending surface of the basement. The performed analysis and the respective images offer a good degree of certainty of the geometric model of the Curitiba Basin and of the morphostructure of its basement. The surface trend allows to sketch with a greater degree of confidence the structural contour of the topgraphic surface (figs. 5 and 6) and of the basement (figs. 7 and 8), as well as the delimitation of intermediate structural heights, which were responsible for isolated and assymmetric depocenters. These details are shown in the map of figures 9 and 10. Thus, the Curitiba Basin is made up by a structural trough stretching NE-SW, with maximum preserved depths of about 80m, which are separated by heights and depocenters striking NW-SE (fig. 11). These structural features seems to have been controlled by tectonic reactivation during the Tertiary (HASUI, 1990) and which younger dissection was conditioned by neotectonic processes (SALAMUNI and EBERT, 1994).

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Questions: We assess gap size and shape distributions, two important descriptors of the forest disturbance regime, by asking: which statistical model best describes gap size distribution; can simple geometric forms adequately describe gap shape; does gap size or shape vary with forest type, gap age or the method used for gap delimitation; and how similar are the studied forests and other tropical and temperate forests? Location: Southeastern Atlantic Forest, Brazil. Methods: Analysing over 150 gaps in two distinct forest types (seasonal and rain forests), a model selection framework was used to select appropriate probability distributions and functions to describe gap size and gap shape. The first was described using univariate probability distributions, whereas the latter was assessed based on the gap area-perimeter relationship. Comparisons of gap size and shape between sites, as well as size and age classes were then made based on the likelihood of models having different assumptions for the values of their parameters. Results: The log-normal distribution was the best descriptor of gap size distribution, independently of the forest type or gap delimitation method. Because gaps became more irregular as they increased in size, all geometric forms (triangle, rectangle and ellipse) were poor descriptors of gap shape. Only when small and large gaps (> 100 or 400m2 depending on the delimitation method) were treated separately did the rectangle and isosceles triangle become accurate predictors of gap shape. Ellipsoidal shapes were poor descriptors. At both sites, gaps were at least 50% longer than they were wide, a finding with important implications for gap microclimate (e.g. light entrance regime) and, consequently, for gap regeneration. Conclusions: In addition to more appropriate descriptions of gap size and shape, the model selection framework used here efficiently provided a means by which to compare the patterns of two different types of forest. With this framework we were able to recommend the log-normal parameters μ and σ for future comparisons of gap size distribution, and to propose possible mechanisms related to random rates of gap expansion and closure. We also showed that gap shape varied highly and that no single geometric form was able to predict the shape of all gaps, the ellipse in particular should no longer be used as a standard gap shape. © 2012 International Association for Vegetation Science.

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Human intestinal parasites constitute a problem in most tropical countries, causing death or physical and mental disorders. Their diagnosis usually relies on the visual analysis of microscopy images, with error rates that may range from moderate to high. The problem has been addressed via computational image analysis, but only for a few species and images free of fecal impurities. In routine, fecal impurities are a real challenge for automatic image analysis. We have circumvented this problem by a method that can segment and classify, from bright field microscopy images with fecal impurities, the 15 most common species of protozoan cysts, helminth eggs, and larvae in Brazil. Our approach exploits ellipse matching and image foresting transform for image segmentation, multiple object descriptors and their optimum combination by genetic programming for object representation, and the optimum-path forest classifier for object recognition. The results indicate that our method is a promising approach toward the fully automation of the enteroparasitosis diagnosis. © 2012 IEEE.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Background: Although postural changes were already reported in blind adults, no previous study has investigated postural stability in blind children. Moreover, there are few studies which used a stabilometric instrument to measure postural balance. In this study we evaluated stabilometric paramaters in blind children. Methods: We evaluated children between 7 to 12 years old, they were divided into two groups: Blind (n = 11) and age-matched control (n = 11) groups by using computerized stabilometry. The stabilometric examination was performed taking the gravity centers displacement of the individual projected into the platform. Thirthy seconds after the period in which this information was collected, the program defined a medium-pressure center, which was used to define x and y axes displacement and the distance between the pressure center and the platform center. Furthermore, the average sway rate and the body sway area were obtained by dividing the pressure center displacement and the time spent on the task; and by an ellipse function (95% percentille), respectively. Percentages of anterior, posterior, left and right feet weight also were calculated. Variables were compared by using the Student’s t test for unpaired data. Significance level was considered for p <0.05. Results: Displacement of the x axis (25.55 ± 9.851 vs. -3.545 ± 7.667; p <0.05) and average sway rate (19.18 ± 2.7 vs. -10.55 ± 1.003; p <0.001) were increased in the blind children group. Percentage of left foot weight was reduced (45.82 ± 2.017 vs. 52.36 ± 1.33; p <0.05) while percentage of right foot weight was increased (54.18 ± 2.17 vs. 47.64 ± 1.33; p <0.05) in blind children. Other variables did not show differences. Conclusions: Blind children present impaired stabilometric parameters.

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Pós-graduação em Matemática em Rede Nacional - IBILCE

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)