7,883 research outputs found

    Observational constraints for Lithium depletion before the RGB

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    Precise Li abundances are determined for 54 giant stars mostly evolving across the Hertzsprung gap. We combine these data with rotational velocity and with information related to the deepening of the convective zone of the stars to analyse their link to Li dilution in the referred spectral region. A sudden decline in Li abundance paralleling the one already established in rotation is quite clear. Following similar results for other stellar luminosity classes and spectral regions, there is no linear relation between Li abundance and rotation, in spite of the fact that most of the fast rotators present high Li content. The effects of convection in driving the Li dilution is also quite clear. Stars with high Li content are mostly those with an undeveloped convective zone, whereas stars with a developed convective zone present clear sign of Li dilution.Comment: 5 pages, 4 figures. accepted for publicatio

    Toward reduction of artifacts in fused images

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    Most fusion satellite image methodologies at pixel-level introduce false spatial details, i.e.artifacts, in the resulting fusedimages. In many cases, these artifacts appears because image fusion methods do not consider the differences in roughness or textural characteristics between different land covers. They only consider the digital values associated with single pixels. This effect increases as the spatial resolution image increases. To minimize this problem, we propose a new paradigm based on local measurements of the fractal dimension (FD). Fractal dimension maps (FDMs) are generated for each of the source images (panchromatic and each band of the multi-spectral images) with the box-counting algorithm and by applying a windowing process. The average of source image FDMs, previously indexed between 0 and 1, has been used for discrimination of different land covers present in satellite images. This paradigm has been applied through the fusion methodology based on the discrete wavelet transform (DWT), using the à trous algorithm (WAT). Two different scenes registered by optical sensors on board FORMOSAT-2 and IKONOS satellites were used to study the behaviour of the proposed methodology. The implementation of this approach, using the WAT method, allows adapting the fusion process to the roughness and shape of the regions present in the image to be fused. This improves the quality of the fusedimages and their classification results when compared with the original WAT metho

    De las articulaciones entre el subcampo profesional y el subcampo de investigaci ón al interior del Campo académico de las Carreras de Licenciatura en. 16H380

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    Se trata de un proyecto que continúa la línea de investigación que este equipo viene desarrollando desde hace alrededor de nueve años, y que ha intentado dar cuenta de las características y particularidades del estado del conocimiento en el campo de investigación del turismo. En esta instancia, en especial, desde el marco teórico-metodológico que ofrece la Teoría de los Campos, se procurará conocer las articulaciones existentes entre producción, transmisión y transferencia de conocimientos. Para ello se analizarán, de modo relacional, las publicaciones que den cuenta de proyectos de investigación (período 2001-2012) sobre las temáticas de Desarrollo Local y Sustentabilidad, los planes de estudio y los Programas de las asignaturas vinculadas con estas temáticas

    Heritability of motor skills: Study with monozygotic and dizygotic twins

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    El objetivo del estudio fue evaluar el poder relativo de contribución genética y ambiental de la variación de capacidades motoras en gemelos monocigóticos y dicigóticos. Método: participado 88 sujetos divididos en 56 monocigóticos y 32 dicigóticos de ambos sexos. Para la evaluación de la flexibilidad fue realizado el test de flexión de cadera; para la potencia de miembros inferiores fue aplicado el test contra movimiento y para la velocidad de desplazamiento, el test de carrera de 30m. Para determinar el índice de heredabilidad, utilizamos la ecuación: (h²) = (S²DZ–S²MZ)/S²DZx100. Fue utilizado tratamiento descriptivo y el test Shapiro-Wilk. Con la varianza de datos fueron calculados valores de tendencia central. Los datos fueron categorizados en percentiles de 25%. Resultados: flexibilidad 16%, velocidad de desplazamiento 83% y potencia de los miembros inferiores 70%.Conclusión: Fue evidenciado mayor heredabilidad para las variables de potencia y velocidad, y mayor influencia ambiental para la flexibilidadThe aim of the study was to assess the relative power of genetic and environmental contributions to the variation of motor skills in monozygotic and dizygotic twins. Method: For this study, participated 88 people divided in 56 monozygotic and 32 dizygotic twins of both sexes. For the assessment the flexibility, was performed hip flexion test, for assessment the lower limb power, was applied the test against movement and the speed of movement, the 30m running test. To determine the index of heritability, was used an equation: (h ²) = (S ²MZ- S²DZ) / S²DZx100. For the statistic, was used the descriptive treatment and Shapiro-Wilk test. The variance values were calculated, through the tendency central values. Data were categorized into percentiles of 25%. Results: Flexibility was 16% by heritability influence, speed of movement 83% of influence and for the lower limbs power were 70%. Conclusion: In this study was demonstrated higher heritability for the variables of lower limbs power and the speed of movement, and for the flexibility, a greater influence was linked for environmental factor

    Study of scattered radiation during fluoroscopy in hip surgery

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    Objetivo: Medir a intensidade da dose de radiação espalhada em diferentes posições simulando uma intervenção cirúrgica no quadril. Materiais e Métodos: Simulou-se uma intervenção cirúrgica no quadril com apoio da fluoroscopia para estudar a distribuição da radiação espalhada no bloco operatório. Para simular o paciente foi utilizado um simulador antropomórfico de corpo inteiro e para medir a radiação utilizou-se um detector específico para medir raios X. Realizaram-se incidências com um equipamento de raios X tipo arco em C móvel, em modo de escopia contínua, com a ampola a 0° (configuração 1) e a 90° (configuração 2). Os parâmetros operacionais utilizados (voltagem, corrente, tempo de exposição) foram determinados por meio de um estudo estatístico resultante da observação de cirurgias ortopédicas de quadril. Resultados: Em todas as medições observaram-se exposições mais elevadas na configuração 2. Nas medições em função da altura, observaram-se os valores máximos da taxa de dose de 1,167 (± 0,023) µSv/s e 2,278 (± 0,023) µSv/s nas configurações 1 e 2, respectivamente, correspondendo à altura do tórax dos profissionais. No estudo em torno do paciente os valores máximos registraramse na posição ocupada pelo médico cirurgião. Conclusão: Concluiu-se que a exposição à radiação dos profissionais é baixa, podendo ainda ser reduzida mediante o uso de equipamentos de proteção individualObjective: To measure the scattered radiation dose at different positions simulating hip surgery. Materials and Methods: We simulated fluoroscopy-assisted hip surgery in order to study the distribution of scattered radiation in the operating room. To simulate the patient, we used a anthropomorphic whole-body phantom, and we used an X-ray-specific detector to quantify the radiation. Radiographs were obtained with a mobile C-arm X-ray system in continuous scan mode, with the tube at 0° (configuration 1) or 90° (configuration 2). The operating parameters employed (voltage, current, and exposure time) were determined by a statistical analysis based on the observation of orthopedic surgical procedures involving the hip. Results: For all measurements, higher exposures were observed in configuration 2. In the measurements obtained as a function of height, the maximum dose rates observed were 1.167 (± 0.023) µSv/s and 2.278 (± 0.023) µSv/s in configurations 1 and 2, respectively, corresponding to the chest level of health care professionals within the operating room. Proximal to the patient, the maximum values were recorded in the position occupied by the surgeon. Conclusion: We can conclude that, in the scenario under study, health care professionals workers are exposed to low levels of radiation, and that those levels can be reduced through the use of personal protective equipmen

    The Phase Diagram of Fluid Random Surfaces with Extrinsic Curvature

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    We present the results of a large-scale simulation of a Dynamically Triangulated Random Surface with extrinsic curvature embedded in three-dimensional flat space. We measure a variety of local observables and use a finite size scaling analysis to characterize as much as possible the regime of crossover from crumpled to smooth surfaces.Comment: 29 pages. There are also 19 figures available from the authors but not included here - sorr
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