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Search Results: 1 - 10 of 447584 matches for " Thomas M.;Araújo "
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Content-based image retrieval applied to BI-RADS tissue classification in screening mammography
Júlia Epischina Engrácia de Oliveira,Arnaldo de Albuquerque Araújo,Thomas M Deserno
World Journal of Radiology , 2011,
Abstract: AIM: To present a content-based image retrieval (CBIR) system that supports the classification of breast tissue density and can be used in the processing chain to adapt parameters for lesion segmentation and classification.METHODS: Breast density is characterized by image texture using singular value decomposition (SVD) and histograms. Pattern similarity is computed by a support vector machine (SVM) to separate the four BI-RADS tissue categories. The crucial number of remaining singular values is varied (SVD), and linear, radial, and polynomial kernels are investigated (SVM). The system is supported by a large reference database for training and evaluation. Experiments are based on 5-fold cross validation.RESULTS: Adopted from DDSM, MIAS, LLNL, and RWTH datasets, the reference database is composed of over 10 000 various mammograms with unified and reliable ground truth. An average precision of 82.14% is obtained using 25 singular values (SVD), polynomial kernel and the one-against-one (SVM).CONCLUSION: Breast density characterization using SVD allied with SVM for image retrieval enable the development of a CBIR system that can effectively aid radiologists in their diagnosis.
Midair collisions enhance saltation
Marcus V. Carneiro,Nuno A. M. Araújo,Thomas P?htz,Hans J. Herrmann
Physics , 2012, DOI: 10.1103/PhysRevLett.111.058001
Abstract: Here we address the old question in Aeolian particle transport about the role of midair collisions. We find that, surprisingly, these collisions do enhance the overall flux substantially. The effect depends strongly on restitution coefficient and wind speed. We can explain this observation as a consequence of a soft-bed of grains which floats above the ground and reflects the highest flying particles. We make the unexpected observation that the flux is maximized at an intermediate restitution coefficient of about 0.7, which is comparable to values experimentally measured for collisions between sand grains.
Discrete Element Method simulations of the saturation of aeolian sand transport
Thomas P?htz,Amir Omerad?i?,Marcus V. Carneiro,Nuno A. M. Araújo,Hans J. Herrmann
Physics , 2015, DOI: 10.1002/2014GL062945
Abstract: The saturation length of aeolian sand transport ($L_s$), characterizing the distance needed by wind-blown sand to adapt to changes in the wind shear, is essential for accurate modeling of the morphodynamics of Earth's sandy landscapes and for explaining the formation and shape of sand dunes. In the last decade, it has become a widely-accepted hypothesis that $L_s$ is proportional to the characteristic distance needed by transported particles to reach the wind speed (the ``drag length''). Here we challenge this hypothesis. From extensive numerical Discrete Element Method simulations, we find that, for medium and strong winds, $L_s\propto V_s^2/g$, where $V_s$ is the saturated value of the average speed of sand particles traveling above the surface and $g$ the gravitational constant. We show that this proportionality is consistent with a recent analytical model, in which the drag length is just one of four similarly important length scales relevant for sand transport saturation.
Diffusion-weighted MR images and pineoblastoma: diagnosis and follow-up
Gasparetto, Emerson L.;Cruz Jr, L. Celso Hygino da;Doring, Thomas M.;Araújo, Bertha;Dantas, Mário Alberto;Chimelli, Leila;Domingues, Romeu C.;
Arquivos de Neuro-Psiquiatria , 2008, DOI: 10.1590/S0004-282X2008000100015
Abstract: pineoblastomas are uncommon pineal tumors, which demonstrate rapid growing and poor prognosis. we report the case of a 43-year-old man with an enhancing pineal region mass, which showed restriction of the diffusion on diffusion-weighted (dw) mr images. the surgical biopsy defined the diagnosis of pineoblastoma and the therapy was initiated with radiation and chemotherapy. three months later, the follow-up mr imaging showed areas suggestive of necrosis and the dw images demonstrate no significant areas of restricted diffusion. the differential diagnosis of pineal region masses that could show restriction of diffusion is discussed.
The defensive strike of five species of lanceheads of the genus Bothrops (Viperidae)
Araújo, MS.;Martins, M.;
Brazilian Journal of Biology , 2007, DOI: 10.1590/S1519-69842007000200019
Abstract: we studied the defensive strike of one species of each of five recognized lineages within the genus bothrops, namely, b. alternatus, b. jararaca, b. jararacussu, b. moojeni and b. pauloensis. the defensive strike of the studied species was in general similar to that of crotalus viridis and c. atrox, but some important differences were observed. bothrops alternatus and b. pauloensis struck preferentially from a tight body posture, whereas b. jararaca and b. moojeni from a loose body posture. defensive strikes were either true or false (during the latter, the mouth remains closed or partially open). almost all strikes were successful; only on a few occasions snakes missed their target (flawed strikes). strike variables were very conservative among the five species, especially strike distance and height, and one possible explanation may be related to constraints imposed on strike variables as a way of increasing strike accuracy.
The influence of the training of resistance and the aerobic training on the hormonal concentrations of testosterone and cortisol
M.R. Araújo
Motricidade , 2008,
Abstract: The goal of this paper is to review the influence of aerobic training and resistance in the acute and chronic concentrations of hormones testosterone and cortisol. In addition, it looks at other important factors, such as age, feeding and circadian rhythm which can modify the concentration of testosterone and cortisol acutely thus making it difficult the understanding of the hormonal answers unchained by the training. Although the diverse controversies found in the present study, the periodical and high intensity activitiesseem to stimulate bigger releases of testosterone and little release of cortisol, contributing , consequently, to the levels of force and muscular hypertrophy. However, new studies need to be carried out with adjusted delineations respecting the diverse interactions (feeding, age, sex, level of experience with the physical training, etc.) that involve the physical training.
Influência das variáveis ambientais na fauna acompanhante na pesca da manjuba Anchoa tricolor (Agassiz) (Actinopterygii, Engraulidae) na Baía de Sepetiba, Rio de Janeiro
Silva, Márcio de Araújo;Araújo, Francisco Gerson;
Revista Brasileira de Zoologia , 2003, DOI: 10.1590/S0101-81752003000300001
Abstract: anchoa tricolor (agassiz, 1829) is the only anchovy of commercial importance in sepetiba bay, supporting an intensive commercial fishery by small sized seine boats provide of hydroacustics sounder detecting device. this study analyses the accompanying fauna in the a. tricolor fishery, and the influence of environmental parameters in fish composition. seven samples were taken with a seine net between march and september 1999, capturing 114,430 fish, comprising 17 species and 11 families. engraulidae and clupeidae were the most abundant families, accounting to 94.2 % of the total number of fish. a. tricolor was the most abundant species contributing to more than one half of the total numerical abundance, followed in decreasing order by anchoa januaria (steindachner, 1879), sardinella brasiliensis (steindachner, 1789) and harengula clupeola (cuvier, 1829). a. tricolor showed a highly significant positive correlation with salinity, transparency and depth. a. januaria showed the opposite, being inversely correlated to these parameters and directly correlated to temperature. clupeidae, on the other hand, seems to show a wider distribution in relations to these environmental parameters.
Influência das variáveis ambientais na fauna acompanhante na pesca da manjuba Anchoa tricolor (Agassiz) (Actinopterygii, Engraulidae) na Baía de Sepetiba, Rio de Janeiro
Silva Márcio de Araújo,Araújo Francisco Gerson
Revista Brasileira de Zoologia , 2003,
Abstract: Anchoa tricolor (Agassiz, 1829) is the only anchovy of commercial importance in Sepetiba Bay, supporting an intensive commercial fishery by small sized seine boats provide of hydroacustics sounder detecting device. This study analyses the accompanying fauna in the A. tricolor fishery, and the influence of environmental parameters in fish composition. Seven samples were taken with a seine net between March and September 1999, capturing 114,430 fish, comprising 17 species and 11 families. Engraulidae and Clupeidae were the most abundant families, accounting to 94.2 % of the total number of fish. A. tricolor was the most abundant species contributing to more than one half of the total numerical abundance, followed in decreasing order by Anchoa januaria (Steindachner, 1879), Sardinella brasiliensis (Steindachner, 1789) and Harengula clupeola (Cuvier, 1829). A. tricolor showed a highly significant positive correlation with salinity, transparency and depth. A. januaria showed the opposite, being inversely correlated to these parameters and directly correlated to temperature. Clupeidae, on the other hand, seems to show a wider distribution in relations to these environmental parameters.
Potential of Wood Ash as a Fertilizer in BRS Piatã Grass Cultivation in the Brazilian Cerrado Soil  [PDF]
Edna Maria Bonfim-Silva, Marcel Thomas Job Pereira, Tonny José Araújo Da Silva, William Fenner
American Journal of Plant Sciences (AJPS) , 2017, DOI: 10.4236/ajps.2017.810156
Abstract: Utilizing wood ash as a fertilizer in agriculture is a viable alternative to the soil nutrients absorbed by the crops. The aim of this study was to assess the phytometric and productive features of Brachiaria brizantha (cv. BRS Piatã) fertilized with wood ash in the Brazilian Cerrado. The experiment was performed in a greenhouse, adopting a completely randomized design, and applying five rates of wood ash (0, 5, 10, 15 and 20 g·dm-3) with five replicates. The shoot plant parts were subjected to three successive cuts 30-day intervals each. The results were submitted to the analysis of variance and regression analysis at 5% probability. The wood ash rates between 13 to 17 g·dm-3 clearly produced the best results for plant height (102.24, 84.42 and 63.27 cm), leaf/stem ratio (1.61, 1, 78 and 1.94), and chlorophyll index (46.66, 41.93 and 38.39), respectively, during the first, second and third evaluations. A 94% increase in the shoot dry mass (2nd and 3rd evaluations) and root parts was noted for the wood ash rate of 20 g·dm-3, compared with the treatment involving wood ash fertilization. Wood ash affects the phytometric features, increases the chlorophyll concentration and thus the BRS Piatã grass production in the Oxisol of the Brazilian Cerrado.
La aplicación de datos faunísticos para el dise o de redes de reservas: el caso de los anfibios y reptiles de la Península Ibérica
Lobo, J. M.,Araújo, M. B.
Graellsia , 2003,
Abstract: Real-world reserve selection decisions are still performed without use of available reserve selection tools that maximise conservation benefit for a minimum cost. In this paper we investigate the consequences of using different reserve selection strategies (richness hotspots, rarity hotspots and maximum covering solutions) to represent amphibian and reptiles species diversity in the Iberian Peninsula. We compare results with that observed in current reserve networks and that expected by chance. We found that current reserves conserve fewer amphibian and reptiles species than expected by chance and that great improvements could be achieved if maximum covering solutions were used to support reserve selection decisions. We recommend that conservation planners and other decision makers use available knowledge and technology for the selecting of important areas for biodiversity. Otherwise, there is a risk that limited resources are invested in such a way as to provide poor conservation return. A pesar de que disponemos de herramientas de selección de reservas que permiten maximizar la representación de las especies con un mínimo coste, las decisiones sobre la ubicación de nuestra red de espacios protegidos siguen realizándose todavía sin el concurso de estas técnicas. En este trabajo se estudian y comparan los resultados de estrategias distintas de selección de reservas (puntos de máxima riqueza, puntos de máxima rareza y solución de máxima cobertura), estimando su efectividad a la hora de representar la diversidad de anfibios y reptiles ibéricos. Los resultados obtenidos han sido comparados, tanto con una selección al azar, como con una selección que considera la ubicación actual de las reservas. Los espacios naturales protegidos no permiten representar la diversidad de anfibios y reptiles ibéricos mejor de lo que lo haría una selección de reservas al azar, mientras que la solución de máxima cobertura permite obtener niveles de representación de las especies mucho mayores que cualquier otra estrategia. Sería recomendable que los gestores ambientales seleccionaran las áreas de conservación utilizando los eficaces algoritmos de selección disponibles. Si no se hace así, corremos el riesgo de que la inversión en conservación de nuestros limitados recursos produzca una baja rentabilidad.
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