226 research outputs found

    Transformations of harmonic bundles and Willmore surfaces

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    Willmore surfaces are the extremals of the Willmore functional (possibly under a constraint on the conformal structure). With the characterization of Willmore surfaces by the (possibly perturbed) harmonicity of the mean curvature sphere congruence [Blaschke, Ejiri, Rigoli, Burstall-Calderbank], a zero-curvature formulation follows [Burstall-Calderbank]. Deformations on the level of harmonic maps prove to give rise to deformations on the level of surfaces, with the definition of a spectral deformation [Burstall-Pedit-Pinkall, Burstall-Calderbank] and of a Baecklund transformation [Burstall-Quintino] of Willmore surfaces into new ones, with a Bianchi permutability between the two [Burstall-Quintino]. This text is dedicated to a self-contained account of the topic, from a conformally-invariant viewpoint, in Darboux's light-cone model of the conformal nn-sphere.Comment: v2: some extra detail added, 35 page

    Finite-size scaling analysis of the critical behavior of a general epidemic process in 2D

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    AbstractWe investigate the critical behavior of a stochastic lattice model describing a General Epidemic Process. By means of a Monte Carlo procedure, we simulate the model on a regular square lattice and follow the spreading of an epidemic process with immunization. A finite size scaling analysis is employed to determine the critical point as well as some critical exponents. We show that the usual scaling analysis of the order parameter moment ratio does not provide an accurate estimate of the critical point. Precise estimates of the critical quantities are obtained from data of the order parameter variation rate and its fluctuations. Our numerical results corroborate that this model belongs to the dynamic isotropic percolation universality class. We also check the validity of the hyperscaling relation and present data collapse curves which reinforce the accuracy of the estimated critical parameters

    Índices de crescimento e componentes da produção do milho e soja em sistemas agrossilvipastoris.

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    Orientador: Prof. Dr. JOADIL GONÇALVES DE ABREU; Co-orientador: Dr. ROBERTO GIOLO DE ALMEID

    Dressing transformations of constrained Willmore surfaces

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    Ensilagem de gramíneas tropicais em sistema de integração lavoura pecuária.

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    O objetivo deste estudo foi avaliar a ensilagem de Brachiaria brizantha cv. BRS Piatã e de Sorghum spp. cv. BRS 800, em monocultivo e em consórcio, em sucessão à cultura da soja, em sistema de integração lavoura-pecuária

    Los moluscos del cesped algal intermareale en Azores

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    The molluscan fauna of the high intertidal algal turf on the island of Pico (Azores) was studied in order to complement existing descriptions of the intertidal biota on these islands. A total of 15,275 specimens belonging to 19 species were found. Five species, the gastropods Alvania mediolittoralis Gofas, 1989, Omalogyra atomus (Philippi, 1841), Pisinna glabrata (Megerle von Muhlfeld, 1824) and Skeneopsis planorbis (Fabricius 0., 1780), and the bivalve Lasaea adansoni (Gmelin, 1791), account for 98% of the total number of specimens, P. glabrata itself being responsible for 46% of all specimens. In places where patellid limpets are absent, Ihe algal turf extends higher in the intertidal zone. In such places, three very abundant molluscan species characterize molluscan assemblages in the algal turf: Lasaea adansoni, Skeneopsis planorbis and Pisinna glabrata, Lasaeo adansoni and Skeneopsis planorbis virtually disappear in the transition from algal lurf to algal fronds, the only (very) abundant species being P. glabrata and, with less importance, Omalogyra atomus and Sinezona cingulata (Costa O.G., 1861)

    Evaluation of respiratory muscle strength in overweight/obese children and adolescents

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    OBJECTIVE: Evaluate respiratory muscle strength in overweight/obese children and adolescents. METHODS: This cross-sectional study enrolled patients between four and 15 years old, classified according to the National Center for Health Statistics curve for body mass index (BMI): Overweight/Obese Group (OG, BMI> 85th percentile) and Normal Weight Group (NG, BMI between 5th and 85th percentile). Manuvacuometer was used to measure maximal inspiratory pressure (MaxInspP) and maximal expiratory pressure (MaxExpP). Three measurements were obtained using the maximum pulmonary effort and the higher value was considered. Variables were compared by t test chi-square test. Adjustment of possible covariants was made by analysis of covariance, being significant p<0.05. RESULTS: 69 children were included: 37 (54%) in the OG and 32 (46%) in the NG. Obese patients were younger: 9.8±2.3 versus 10.9±1.9 years (p=0.031). MaxInspP was 71.4±24.9cmH2O in the OG and 89.6±19.6cmH2O (p=0.002). MaxExpP was 71.9±24.8cmH2O in the OG and 95.6±19.6cmH2O in the NG (p<0.001). There was no difference between groups regarding gender and physical activity. After adjustment for age, only the MaxExpP was significantly different between groups (p=0.003). CONCLUSIONS: Maximal expiratory pressure was lower in overweight/obese patients, indicating that obesity may alter pulmonary mechanics.OBJETIVO: Avaliar a força muscular respiratória de crianças e adolescentes com sobrepeso ou obesidade. MÉTODOS: Estudo transversal com crianças e adolescentes entre quatro e 15 anos de idade de duas instituições de ensino fundamental e uma clínica de nutrição. As crianças foram avaliadas e classificadas em dois grupos, de acordo com a curva proposta pelo National Center for Health Statistics: sobrepeso/obesos (GSO, índice de massa corpórea (IMC) em relação à idade e ao sexo acima do percentil 85) e eutróficos (GE, IMC entre percentil 5 e 85). Para avaliar as pressões inspiratória máxima (PImax) e expiratória máxima (PEmax) foram realizadas três medidas com um manovacuômetro, considerando-se a maior medida a partir da capacidade máxima inspiratória e expiratória. Aplicou-se o teste t para as variáveis quantitativas e o qui-quadrado para as qualitativas. Para ajuste das covariáveis, foi feita a análise de covariância, sendo significante p<0,05. RESULTADOS: Foram avaliadas 69 crianças: 37 (54%) do GSO e 32 (46%) eutróficos. O GSO apresentou menor idade (9,8±2,3 versus 10,9±1,9 anos; p=0,03). A PImax foi 71,4±24,9cmH2O no GSO e 89,6±19,6cmH2O nos eutróficos (p=0,002). A PEmax foi 71,9±24,8cmH2O no GSO e 95,6±19,6cmH2O nos eutróficos (p<0,001). Não houve diferenças quanto ao sexo e à prática de atividade física. Ajustando-se os valores em relação à idade, somente a PEmax manteve-se diferente entre os grupos (p=0,003). CONCLUSÕES: A força muscular expiratória mostrou-se diminuída nesta amostra de crianças e adolescentes com sobrepeso/obesidade, indicando que a obesidade pode comprometer a mecânica pulmonar dessa população.UNIFESPUniversidade Guarulhos Unidade de Terapia Intensiva AdultoHospital Alemão Oswaldo CruzUNIFESP, EPM, São PauloSciEL
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