1,379 research outputs found

    Criticalidade auto-organizada no cerrado? Invariância escalar dos padrões texturais e espectrais de fitosionomias do cerrado paulista.

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    Padrões presentes em uma paisagem podem estar associados importantes processos relativos à organização e dinâmica do sistema. Objetivo: O objetivo do presente trabalho foi avaliar, a partir de algumas métricas derivadas do paradigma da complexidade, a complexidade dos padrões texturais e espectrais de fisionomias do Cerrado paulista a fim de verificar quais propriedades relativas à sua organização e dinâmica tais padrões podem revelar. Metodologia: Para tanto, imagens do sensor Aster de três unidades de conservação do estado de São Paulo foram analisadas, utilizando-se dois tipos de medidas (dimensão fractal e medidas baseadas na entropia informacional) para avaliar a complexidade dos padrões texturais e espectrais das fisionomias. Resultados e discussão: Todas as fisionomias, nas três localidades estudadas e para todas as medidas usadas, apresentarem em diversas ocasiões a ocorrência de padrões texturais e espectrais que se repetem em diferentes escalas. A principal implicação desses resultados diz respeito às inferências sobre a dinâmica do Cerrado: a invariância escalar é uma característica marcante de sistemas que se desenvolvem longe do equilíbrio. Mais do que isso, é um grande indicativo de que o sistema pode apresentar criticalidade auto-organizada.Edição especia

    Self-control in Sparsely Coded Networks

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    A complete self-control mechanism is proposed in the dynamics of neural networks through the introduction of a time-dependent threshold, determined in function of both the noise and the pattern activity in the network. Especially for sparsely coded models this mechanism is shown to considerably improve the storage capacity, the basins of attraction and the mutual information content of the network.Comment: 4 pages, 6 Postscript figure

    A moment based approach to the dynamical solution of the Kuramoto model

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    We examine the dynamics of the Kuramoto model with a new analytical approach. By defining an appropriate set of moments the dynamical equations can be exactly closed. We discuss some applications of the formalism like the existence of an effective Hamiltonian for the dynamics. We also show how this approach can be used to numerically investigate the dynamical behavior of the model without finite size effects.Comment: 6 pages, 5 figures, Revtex file, to appear in J. Phys.

    Assessment of complexity metrics applied to analysis of spectral patterns generated by aster sensor.

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    Landscape metrics are traditionally used in the analysis and search for spatial patterns in complex environmental systems through of establishing numeric relationships between different types of targets on Earth's surface. Under this perspective, remote sensing has had great importance as a tool for data generation, providing several levels of land use and occupancy information isonomically for large areas. For that purpose, remote sensing uses regular pixel matrices (Picture Element) with associated quantitative values (e.g. digital numbers, radiance, reflectance) which constitute a direct measurement of the variation of electromagnetic radiation (EMR) after interaction with the target. The variations in pixel values may be considered in terms of their textural patterns, regarding pixel neighborhood relationships, or spectral patterns, when EMR variations are considered along different wavelengths for a same pixel. Thus, the objective of this work was to assess the results of spectral measurements to different area extensions in images taken by the ASTER sensor, which operates with 9 bands within the visible to shortwave infrared region (0.556 to 2.400 µm) and has a spatial resolution of 15 m. For this purpose, cerrado phytophysiognomies in two hillsides at Jataí Ecological Station, in the city of Luiz Antônio, northeast portion of the state of São Paulo, Brazil, were considered reference targets, and encompassed to its greatest extent the cerradão domain and also "campo sujo" and "cerrado strictu sensu" physiognomies. The metrics used for spectral analyses are based on information entropy: measure (SDL), in which most complexity values are associated to more disorderly patterns; and measure, LMC, which is represent by a convex entropy of function that attributes greater complexity values to patterns located in an intermediate zone between order and disorder. These measures was applied to values extracted from spectral response curve generated by a wavelength X reflectance graphic which represented the target's behavior in different bands of the electromagnetic spectrum. In this work, was used two bands (8 and 9) that emphasize important components of cerrado phytophysiognomies, as lignin and water cell. For each hillside, was analysed three positions: base, medium and top, and each of these position, two spatial scales (150x150m and 75x75m). The results shows that, when taken alone, any measure presented a consistent behavior when compared of different spatial scales and bands used. However, both measures show identical behavior to attribute greater and lesser values of complexity to different positions and spatial scale at the same hillside. This results appoint that its can be used in combined as complementary measures, demonstrating in case LMC measure ? heterogeneity degrees of spectral patterns analysed and, from SDL measure, your respective location along of continuum that have in your extremes, one side, more ordered condition (therefore, more homogeneous) and, in the other extremity, more disordered conditions

    ¿Están preparados los médicos españoles del mañana para combatir la inactividad física?

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    El objetivo del estudio fue averiguar que conocimientos tenían los estudiantes de medicina españoles sobre las recomendaciones actuales de Actividad Física (AF) de la Organización Mundial de la Salud (OMS). Un total de 334 estudiantes de medicina (2º-6º curso) de 29 universidades españolas cumplimentaron un cuestionario de conocimientos sobre las recomendaciones de AF de la OMS. El 100% de los encuestados afirmaron que recomendar AF es una parte importante del trabajo de un médico, pero sólo un 34,1% se sentían preparados para ello. Un 85,0% y un 72,5% desconocían las recomendaciones de AF de la OMS para adultos y niños respectivamente. El 94,3% demandaron una mayor formación académica en AF, siendo el método de preferencia la asignatura optativa. La falta de conocimiento sobre las recomendaciones de AF de los estudiantes de medicina españoles es evidente y alarmante. Aumentar la formación en dichos contenidos mediante asignaturas optativas podría revertir esta situación. The aim of this study was to evaluate the level of knowledge that Spanish medical students had about current global physical activity (PA) recommendations provided by the World Health Organization (WHO). A total of 334 medical students (2nd-6th degree years) from 29 Spanish universities completed a questionnaire of knowledge about WHO’s global PA recommendations. All respondents (100%) stated that recommending PA is an important part of a physician ´s role, but only 34.1% felt prepared for it. 85.0% and 72.5% of respondents did not know the PA recommendations for adults and children respectively. Likewise, 94.3% of respondents demanded more education in PA, with an optional/elective subject during the degree, being the preferred method of learning. The lack of knowledge regarding PA recommendations by medical students is evident and alarming. Increasing the education focused on these contents through optional subjects could reverse this situation

    New Evidence on Regucalcin, Body Composition, and Walking Ability Adaptations to Multicomponent Exercise Training in Functionally Limited and Frail Older Adults

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    Background: Regucalcin, or senescence marker protein-30 (SMP30), is a Ca2+-binding protein with multiple functions reported in the literature. Physical exercise has been shown to improve aging markers; nevertheless, SMP30 in humans has not been extensively researched. Older adults experience a decline in functional capacity and body composition. The purpose of this study was to examine the effects of a multicomponent training (MCT) program on SMP30 and its regulation of walking ability and body composition in functionally limited, frail, and pre-frail older adults. Methods: A total of 34 older adults (aged 80.3 +/- 6.1 years) were divided into an intervention group (IG = 20) and control group (CG = 14). The IG performed a supervised MCT (strength, endurance, balance, coordination, and flexibility) program for 6 months, 3 days per week, whereas the CG continued their normal lives without any specific physical training. SMP30 was analyzed in plasma after 3 and 6 months of MCT, while some physical fitness variables (Timed Up and Go (TUG) and 6-min walk test (6MWT)) and body composition (fat mass and lean mass) were measured at baseline, as well as after 3 months and 6 months of MCT. Results: No significant changes were observed in SPM30 between the IG (877.5 a.u. to 940.5 a.u., respectively) and CG (790.4 a.u. to 763.8 a.u., respectively). Moreover, no SMP30 differences were found between groups after 3 and 6 months of MCT. The IG improved significantly in the 6MWT after 3 months (472.2 +/- 84.2 m) compared to baseline (411.2 +/- 75.2 m). The IG also significantly enhanced their TUG performance after 3 months (7.6 +/- 1.6 s) and 6 months (7.3 +/- 1.8 s) of training compared to baseline (9.3 +/- 3.2 s) (all, p < 0.001). There were no significant differences in body composition between the IG and CG through the 6 months of MCT. Conclusions: The present study suggests that MCT did not change SMP30 levels from 3 to 6 months, where there were changes in neither walking ability nor body composition; however, MCT was effective in improving 6MWT and TUG performance from baseline to 3 months

    Prediction of Reverse Remodeling at Cardiac MR Imaging Soon after First ST-Segment-Elevation Myocardial Infarction: Results of a Large Prospective Registry

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    [EN] Conclusion: Assessment of infarct size and MVO with cardiac MR imaging soon after STEMI enables one to make a decision in the prediction of reverse remodeling. (C) RSNA, 2015Supported by the Instituto de Salud Carlos III and FEDER (grant PI1400271) and the Generalitat Valenciana (grant PROMETEO/2013/007).Bodi, V.; Monmeneu, J.; Ortiz-Perez, J.; López-Lereu, M.; Bonanad, C.; Husser, O.; Minana, G.... (2016). Prediction of Reverse Remodeling at Cardiac MR Imaging Soon after First ST-Segment-Elevation Myocardial Infarction: Results of a Large Prospective Registry. Radiology. 278(1):54-63. https://doi.org/10.1148/radiol.2015142674S5463278
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