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Search Results: 1 - 10 of 578111 matches for " Jo?o M. B. Carreiras "
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Estimating the Above-Ground Biomass in Miombo Savanna Woodlands (Mozambique, East Africa) Using L-Band Synthetic Aperture Radar Data
Joo M. B. Carreiras,Joana B. Melo,Maria J. Vasconcelos
Remote Sensing , 2013, DOI: 10.3390/rs5041524
Abstract: The quantification of forest above-ground biomass (AGB) is important for such broader applications as decision making, forest management, carbon (C) stock change assessment and scientific applications, such as C cycle modeling. However, there is a great uncertainty related to the estimation of forest AGB, especially in the tropics. The main goal of this study was to test a combination of field data and Advanced Land Observing Satellite (ALOS) Phased Array L-band Synthetic Aperture Radar (PALSAR) backscatter intensity data to reduce the uncertainty in the estimation of forest AGB in the Miombo savanna woodlands of Mozambique (East Africa). A machine learning algorithm, based on bagging stochastic gradient boosting (BagSGB), was used to model forest AGB as a function of ALOS PALSAR Fine Beam Dual (FBD) backscatter intensity metrics. The application of this method resulted in a coefficient of correlation (R) between observed and predicted (10-fold cross-validation) forest AGB values of 0.95 and a root mean square error of 5.03 Mg·ha ?1. However, as a consequence of using bootstrap samples in combination with a cross validation procedure, some bias may have been introduced, and the reported cross validation statistics could be overoptimistic. Therefore and as a consequence of the BagSGB model, a measure of prediction variability (coefficient of variation) on a pixel-by-pixel basis was also produced, with values ranging from 10 to 119% (mean = 25%) across the study area. It provides additional and complementary information regarding the spatial distribution of the error resulting from the application of the fitted model to new observations.
Closed Contour Fractal Dimension Estimation by the Fourier Transform
Joo B. Florindo,Odemir M. Bruno
Computer Science , 2012, DOI: 10.1016/j.chaos.2011.07.008
Abstract: This work proposes a novel technique for the numerical calculus of the fractal dimension of fractal objects which can be represented as a closed contour. The proposed method maps the fractal contour onto a complex signal and calculates its fractal dimension using the Fourier transform. The Fourier power spectrum is obtained and an exponential relation is verified between the power and the frequency. From the parameter (exponent) of the relation, it is obtained the fractal dimension. The method is compared to other classical fractal dimension estimation methods in the literature, e. g., Bouligand-Minkowski, box-couting and classical Fourier. The comparison is achieved by the calculus of the fractal dimension of fractal contours whose dimensions are well-known analytically. The results showed the high precision and robustness of the proposed technique.
Texture analysis by multi-resolution fractal descriptors
Joo B. Florindo,Odemir M. Bruno
Computer Science , 2014, DOI: 10.1016/j.eswa.2013.01.007
Abstract: This work proposes a texture descriptor based on fractal theory. The method is based on the Bouligand-Minkowski descriptors. We decompose the original image recursively into 4 equal parts. In each recursion step, we estimate the average and the deviation of the Bouligand-Minkowski descriptors computed over each part. Thus, we extract entropy features from both average and deviation. The proposed descriptors are provided by the concatenation of such measures. The method is tested in a classification experiment under well known datasets, that is, Brodatz and Vistex. The results demonstrate that the proposed technique achieves better results than classical and state-of-the-art texture descriptors, such as Gabor-wavelets and co-occurrence matrix.
Seasonal Flavonoid Profile and Kaempferitrin Content in the Leaf Extracts of Bauhinia forficata Subspecies forficata from Two Locations in Southeastern Brazil  [PDF]
Joo B. F. Tostes, Antonio C. Siani, Sérgio S. Monteiro, Vinicius F. Melo, Jéssica O. Costa, Ligia M. M. Valente
American Journal of Plant Sciences (AJPS) , 2019, DOI: 10.4236/ajps.2019.101016
Abstract: The leaves of Bauhinia forficata L. (Fabaceae) are used in Brazilian folk medicine mainly as antidiabetic agent. They are rich in polyphenols, and kaempferitrin and other flavonoids are currently considered as basic chemical criteria for the quality and the effectiveness of extracts and phytopharmaceuticals derived from them. Aiming to expand the scope of current data of the chemical profile of B. forficata subsp. forficata, the present study employed HPLC-DAD and HPLC-DAD-ESI/MS to compare the flavonoid profile and kaempferitrin content in the leaves of specimens collected seasonally during one year, in two different locations in Southeastern Brazil: Rio de Janeiro (RJ) and São Paulo (SP) states. The data showed a variation in the flavonoid profile and in the kaempferitrin content depending on the place of collection and the season of the year. The target compound, kaempferitrin, was found to be only a minor constituent in RJ (0.21 - 1.02 μg/mg), and was mostly absent or occurred as trace in SP location (0.00 - 0.12 μg/mg). Some degree of similarity was observed in the flavonoid profiles according to the region of collection. In agreement with some published reports, the low and quite variable kaempferitrin content as well the wide variability of the flavonoid profiles brings into question the dubious matter of using these compounds as chemical markers for this medicinal species.
Orienta??es básicas para os enfermeiros na ministra??o de psicofármacos
Marcolan, Joo Fernando;Urasaki, Maristela B. M.;
Revista da Escola de Enfermagem da USP , 1998, DOI: 10.1590/S0080-62341998000300004
Abstract: whit this study the autors want to furnish the nurses with one more reference source to guide their actions in caring for the patient that use psichopharmaco. it is describet the pharmacological groups and considerations are made about the care with patients that are using them.
Did the first Global Fund grant (2003–2006) contribute to malaria control and health system strengthening in Timor-Leste?
Martins Joo,Zwi Anthony B,Kelly Paul M
Malaria Journal , 2012, DOI: 10.1186/1475-2875-11-237
Abstract: Background In 2003, Timor-Leste successfully obtained its first Global Fund grant for a three-year programme for malaria control. The grant aimed to reduce malaria-related morbidity and mortality by 30 % by the end of the implementation. Methods A mixed-methods approach was used to assess the impact of the grant implementation. Fifty-eight in-depth interviews, eight group interviews, 16 focus group discussions, and on-site observations were used. Morbidity data reported to the Ministry of Health were also examined to assess trends. Results The National Malaria Programme with funding support from the Global Fund grant and other development partners contributed considerably to strengthening malaria control and the general health system. It also brought direct and indirect benefits to pregnant women and to the community at large. However, it failed to achieve the stated objective of reducing malaria morbidity and mortality by 30 %. The implementation was hampered by inadequate human resources, the rigidity of Global Fund rules, weak project management and coordination, and inadequate support from external stakeholders. Conclusion Despite limitations, the grant was implemented until the agreed closing date. Considerable contributions to malaria control, health system, and the community have been made and the malaria programme was sustained.
Shape analysis using fractal dimension: a curvature based approach
André R. Backes,Joo B. Florindo,Odemir M. Bruno
Computer Science , 2012, DOI: 10.1063/1.4757226
Abstract: The present work shows a novel fractal dimension method for shape analysis. The proposed technique extracts descriptors from the shape by applying a multiscale approach to the calculus of the fractal dimension of that shape. The fractal dimension is obtained by the application of the curvature scale-space technique to the original shape. Through the application of a multiscale transform to the dimension calculus, it is obtained a set of numbers (descriptors) capable of describing with a high precision the shape in analysis. The obtained descriptors are validated in a classification process. The results demonstrate that the novel technique provides descriptors highly reliable, confirming the precision of the proposed method.
Revisiting Complex Moments For 2D Shape Representation and Image Normalization
Joo B. F. P. Crespo,Pedro M. Q. Aguiar
Computer Science , 2010, DOI: 10.1109/TIP.2011.2146264
Abstract: When comparing 2D shapes, a key issue is their normalization. Translation and scale are easily taken care of by removing the mean and normalizing the energy. However, defining and computing the orientation of a 2D shape is not so simple. In fact, although for elongated shapes the principal axis can be used to define one of two possible orientations, there is no such tool for general shapes. As we show in the paper, previous approaches fail to compute the orientation of even noiseless observations of simple shapes. We address this problem. In the paper, we show how to uniquely define the orientation of an arbitrary 2D shape, in terms of what we call its Principal Moments. We show that a small subset of these moments suffice to represent the underlying 2D shape and propose a new method to efficiently compute the shape orientation: Principal Moment Analysis. Finally, we discuss how this method can further be applied to normalize grey-level images. Besides the theoretical proof of correctness, we describe experiments demonstrating robustness to noise and illustrating the method with real images.
Gabor wavelets combined with volumetric fractal dimension applied to texture analysis
álvaro Gomez Z.,Joo B. Florindo,Odemir M. Bruno
Computer Science , 2014, DOI: 10.1016/j.patrec.2013.09.023
Abstract: Texture analysis and classification remain as one of the biggest challenges for the field of computer vision and pattern recognition. On this matter, Gabor wavelets has proven to be a useful technique to characterize distinctive texture patterns. However, most of the approaches used to extract descriptors of the Gabor magnitude space usually fail in representing adequately the richness of detail present into a unique feature vector. In this paper, we propose a new method to enhance the Gabor wavelets process extracting a fractal signature of the magnitude spaces. Each signature is reduced using a canonical analysis function and concatenated to form the final feature vector. Experiments were conducted on several texture image databases to prove the power and effectiveness of the proposed method. Results obtained shown that this method outperforms other early proposed method, creating a more reliable technique for texture feature extraction.
Efeito da temperatura e da luz na germina??o de sementes de Acacia polyphylla DC.
Araújo Neto, Joo C.;Aguiar, Ivor B.;Ferreira, Vilma M.;
Brazilian Journal of Botany , 2003, DOI: 10.1590/S0100-84042003000200013
Abstract: acacia polyphylla (leguminosae-mimosoideae) is a typical tree species of secondary succession in brazil, important for restoration of degraded areas. the purpose of this work was to evaluate the seed germination under different temperatures and light conditions. constant (15, 20, 25 and 30 oc) and alternating (20-30 oc) temperatures were evaluated, at an eight hours photoperiod under white light. constant temperature of 25 oc was optimal and the light experiments were conducted at that temperature. seeds were incubated in darkness and at photoperiods from 1 to 12 hours under white light (high red/far-red ratio), as well as at photoperiods under white light initiated and concluded with shade light (low red/far-red ratio). germination percentage was not affected by the photoperiods under white light tested, but a photoperiod similar or higher than four hours was required for better initial seedling growth. both germination percentage and speed was not affected by light of a low red/far-red ratio, but they decreased in darkness.
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