THREE-DIMENSIONAL RECONSTRUCTION OF THE HUMAN MOTION BASED ON IMAGES FROM A SINGLE CAMERA

It is widely accepted that the photograms of two or more cameras are required for the spatial reconstruction of the human motion. Each projection of the spatial coordinates of a given anatomical point of the human body is described by two equations. Consequently, two or more cameras are necessary for at least three independent linear equations required to obtain the original three coordinates of the point from its projected positions. If n cameras are used in the reconstruction process 2n equations are available for that purpose. In this case more equations than unknowns are available, and the solution for the reconstruction must minimize the error in those equations. Regardless of the number of cameras available, no information of the biomechanical model is generally used during the reconstruction process. In this work, a biomechanical model of 16 segments is used to support the motion reconstruction. The kinematic equations that characterize the dependency between the Cartesian coordinates of the points describing each component of the biomechanical model are used together with the two equations describing their projection in each frame. The single triangle describing the lower torso is defined by three points corresponding to nine spatial coordinates. For a given frame of a single camera six independent linear equations are defined. The remaining three equations needed to the spatial reconstruction of the triangle are the kinematic constraint equations ensuring that the distance between each two points remains constant throughout the motion. The system of nonlinear equations defined in this form has multiple solutions. For each subsequent camera frame the same process is followed to obtain the multiple solutions of the triangle reconstruction. The motion of the triangle representing the lower torso is selected as the combination of the solutions of the independent frames that minimizes a given function, defined as a measure of the smoothness of the triangle motion, variation of its angular orientation or increment of its distance between frames. Only the two solutions for the motion corresponding to the lower values of the functional, evaluated during four frames, are kept. Assuming that the motion for both solutions is feasible for the remaining frames, the method proceeds with the reconstruction of the segments adjacent to the lower torso, followed by the segments adjacent to the first set and so forth. A branch of solutions is eliminated if it cannot proceed from one frame to the next, either because no solution is possible or because the reconstructed motion develops behind the camera. Finally the reconstruction of the full motion is obtained in an automatic form. The methodology is applied to a case of complex human body motion demonstrating that it is feasible to reconstruct the three dimensional human motion using the photograms of a single stationary camera and a consistent biomechanical model

Substituindo o uso de bordaduras laterais por repetições em experimentos com milho Replacing lateral borders by replications in corn experiments

O uso de bordaduras, aliado ao número adequado de repetições para definir um plano experimental, tem sido pouco estudado. Dois híbridos de milho foram avaliados com o objetivo de estimar o número de repetições necessários, substituindo-se o uso de bordaduras laterais por um maior número de filas por parcela. Foram utilizados oito tratamentos que proporcionaram comparar parcelas de duas, três, quatro e cinco filas, com e sem as duas bordaduras laterais, além de duas e três filas com bordadura simples. Verificou-se que não houve diferenças entre as estimativas das médias de híbridos e dos diferentes tipos de parcelas e nem efeito da interação entre tipos de parcelas e híbridos. Constatou-se homogeneidade nas estimativas das variâncias entre os tipos de parcelas para os dois híbridos. Em experimentos de comparação de híbridos de milho, não é vantajoso substituir o uso de bordaduras por um número maior de repetições. No entanto, um maior número de repetições, sendo que oito repetições de parcelas de duas filas, proporcionam os planos experimentais mais precisos.<br>Few studies were conducted so far in regard to the use of row borders and number of replications to define an experimental plan. Therefore an experiment was conducted in order to estimate the number of replications necessary to substitute greater row numbers of the plot for the use on row borders. Two corn hybrids were used and eight treatment in which plots with two, three, four and five rows with and without two lateral row borders and two and three row plots with a single border row. There was neither difference among the estimated yield average of the hybrids and the different plots and nor interaction between the plot forms and hybrids as well as homogeneity of variance estimates among the plots of the two hybrids. In hybrid corn yield experiments there is no advantage to substitute the use of row borders for greater number of replications. However, a greater number of replications such as eight replications and two row plots with no border rows, will result in more precise experimental plans

Qualidade dos ensaios de competição de cultivares de milho no Estado do Rio Grande do Sul Quality of cultivar competition experiments with corn in the State of Rio Grande do Sul - Brazil

O objetivo deste trabalho foi estimar a proporção de ensaios com significância para efeito de blocos, cultivares e do atendimento às pressuposições de normalidade e aleatoriedade do erro, homogeneidade das variâncias do erro entre cultivares e a aditividade do modelo necessárias para os testes de hipótese. Também foi objetivo a quantificação do efeito do não atendimento das pressuposições sobre a diferença mínima significativa (DMS), obtida pelo teste de Tukey em nível de 5% de probabilidade. Foram analisados 307 ensaios da rede estadual de competição de cultivares de milho do Estado do Rio Grande do Sul no período de 1993 e 1996. Dos ensaios de competição de cultivares de milho, 85,67% apresentaram efeito significativo para cultivares e, nestes, a média da DMS era igual a 30,28%. O não atendimento às pressuposições para os testes de hipótese ocorreu em baixa freqüência e aumentou a DMS. A falta de aditividade no modelo ocorreu em 8,75% dos ensaios e não modificou a DMS, sendo a transformação indicada ineficiente para a redução da DMS. A causa da falta de aleatoriedade dos erros em 9,88% dos ensaios foi a variabilidade entre as unidades experimentais e/ou o bloqueamento em posição inadequada à variabilidade espacial da fertilidade no local do ensaio.<br>This study aimed to quantify the proportion of experiments with statistical difference for blocks, cultivar and the F test assumption (additivity, normal distribution, random error, and error variance homogeneity among cultivars) observance. Also, the effects on the least significant difference (LSD) based on Tukey test (P=0.05) were quantified when some assumption was not observed. The statistical analysis was based upon 307 sets of experimental cultivar competition data carried out from 1993 to 1996 in the State of Rio Grande do Sul, Brazil. Among the experiments with significant differences in treatments (cultivars), 85.67% had an average LSD equal to 30.28%. Low frequency of non assumption observance was verified and increased the LSD. Lack of additivity on the model occured in 8.75% the trials and not modify LSD of data transformation. No random error effect was verified in 9.88% of the experiments due to variability among plots at the same block caused by inadequate block placement in the experimental area

Evidence for euphotic zone anoxia during the deposition of Aptian source rocks based on aryl isoprenoids in petroleum, Sergipe-Alagoas Basin, northeastern Brazil

Four crude oil samples from the Sergipe-Alagoas Basin, northeastern Brazil, were analyzed using full scan gas chromatography-quadrupole mass spectrometry (GC-qMS) for biomarkers, in order to correlate them using aromatic carotenoids thereby enhancing knowledge about the depositional environment of their source rocks. The geochemical parameters derived from saturated fractions of the oils show evidence of little or no biodegradation and similar thermal maturation (Ts/(Ts+Tm) for terpanes, C29 αββ/(αββ+ααα), C27, and C29 20S/(20S+20R) for steranes). Low pristane/phytane ratios and the abundance of gammacerane and β-carotane are indicative of an anoxic and saline depositional environment for the source rocks. Moreover, we identified a large range of diagenetic and catagenetic products of the aromatic carotenoid isorenieratene, including C40, C33, and C32 diaryl isoprenoids and aryl isoprenoid derivatives with short side chains and/or additional rings. These results indicate anoxia in the photic zone during the deposition of the source rocks. © 2013 The Authors

Macro-nutrientes no lençol freático em Floresta Intacta, Floresta de Manejo e Pastagem no norte de Mato Grosso Macro-nutrients in the water sheet in Mature Forest, Management Forest and Pasture in the north of Mato Grosso

A remoção de uma cobertura florestal e sua substituição por outras formas de uso do solo tem sido uma constante no norte do estado de Mato Grosso podendo alterar os ciclos hidrológicos e biogeoquímicos dos ecossistemas. Neste contexto, o presente trabalho visou identificar a variação do fósforo e nitrogênio das águas do lençol freático em áreas de Floresta de Transição madura e intacta (Floresta Intacta), Floresta de Transição Manejada (Floresta Manejada) e Pastagem localizadas no norte de Mato Grosso. Foram realizadas mensalmente medidas do nível do lençol freático, de coletas de amostras de água para análises físico-químicas e medições de precipitação e temperatura do ar, no período de janeiro/2005 a novembro/2006. Verificou-se uma sazonalidade na precipitação e na temperatura do ar. No período de estiagem as águas do lençol freático apresentaram maiores teores de nitrogênio e de fósforo total nas três áreas em estudo. Os maiores valores de nitrogênio e fósforo foram detectados nos ecossistemas florestais (Florestas Intacta e Manejada) como indicativo da função da cobertura vegetal na ciclagem dos nutrientes.<br>Forest removal for other land uses has been a constant in the north of Mato Grosso and can alter the hydrological and biochemical cycles. In this context, the present work aims to identify the variation of phosphorus and nitrogen in the water sheet in areas of Mature Forest, Management Forest and Pasture in the north of Mato Grosso. The water level was measured monthly and water samples for analysis were collected monthly from January/2005 to November/2006. We verified the precipitation and the air temperature seasonality, and in the dry season the quality of the water sheet presented greater values of total phosphorus and total Kjeldhal nitrogen in the studied areas. The phosphorus and nitrogen presented greater values in forest ecosystems (Forest and Management Forest) as indicative of the function of the vegetal covering in the nutrient cycle