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Search Results: 1 - 10 of 291002 matches for " Girliane R. da Silva "
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Palladium(0)-catalyzed efficient synthesis of allylic N- and S-benzoheterocycles linked to unsaturated carbohydrate derivatives
Ronaldo Nascimento de Oliveira,Wilson S. do Nascimento,Girliane R. da Silva,Tania Maria S. Silva
Orbital : the Electronic Journal of Chemistry , 2012,
Abstract: An efficient strategy was developed to envisage the synthesis of new N- and S-benzoheterocycles attached to the C-4 position of pseudo-carbohydrates. The reaction was performed with unsaturated carbohydrates and benzoheterocycles as nucleophiles in the presence of a catalytic amount of tetrakis(triphenylphosphine)palladium(0) and chelating bidentate ligand dppb. This strategy allowed easy access to benzoheterocyclic sugars in moderate-to-good yields. A preliminary study for antioxidant activities of O-glycosides 2,3-unsaturated was evaluated based on the 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging and 2,2-azinobis 3-ethylbenzothiozoline-6-sulfonic acid (ABTS) radical cation decolorization assay, and showed low-to-moderate activities.
Identification of Sugar, Amino Acids and Minerals from the Pollen of Jandaíra Stingless Bees (Melipona subnitida)  [PDF]
Girliane Regina da Silva, Tamires Botelho da Natividade, Celso Amorim Camara, Eva Monica Sarmento da Silva, Francisco de Assis Ribeiro dos Santos, Tania Maria Sarmento Silva
Food and Nutrition Sciences (FNS) , 2014, DOI: 10.4236/fns.2014.511112
Abstract:

The aim of this investigation was to analyze two samples of pollen from jandaíra stingless bees (Melipona subnitida) in view of their mineral composition, free amino acids and sugars. Palynological analysis showed that the predominant pollen was monofloral from Senna sp. species (94.5%, pollen 2011) and the second pollen sample showed the presence of two primary species, Chamaecrista sp. (39.2% pollen 2009) and Mimosa tenuiflora (43.5%) (pollen 2009). The highest mineral content was potassium. The bee pollen contained 20.8% and 31.0% of mannitol in samples from 2011 and 2009, respectively. Proline and serine are the predominant amino acids. High content of essential amino acids, minerals and the sugar mannitol confirmed high nutritional value of pollen samples from jandaíra bees.

Calibration of Numerical Model Applied to a Shear Zone Located on a Slope in an Open Pit Mine—Case History  [PDF]
Evandro Moraes da Gama, Bruno C. R. da Silva
Geomaterials (GM) , 2012, DOI: 10.4236/gm.2012.21002
Abstract: The instability of a pit mine slope diagnostic caused by the slipping of a localized deep shear zone is described. The slope was designed on ultra basic, serpentine and metabasite rock formations with an angle varying from 40 to 45 de- grees. The perturbed slope zone was classified as RMR 12 and the non-perturbed zone as RMR 75. The boundary of these zones is defined as the shear zone. The pit slope was field mapped in detail and the mechanical properties of the rock were obtained through a laboratory test. The lab data were further processed using the RMR mechanical classifi- cation system. The Distinct Elements Code numerical modeling and simulation software was used to design the pit slope. The model was calibrated through topographic mapping of the points on the ground. The task of calibrating a numerical model is far from simple. Exhaustive attempts to find points of reference are required. The mechanical be- havior in function of the time factor is a problem that has yet to be solved. The instant deformation generated in the numerical model generated functions that can be compared with the deformations of quick shifts acquired in the topog- raphic monitoring. SMR is indeed more often recommended for Pit Slopes, though the fact that we have used RMR does not invalidate the classification for the modeling effect. The main parameters such as spacing, filling, diving direc- tion and continuity allow for compartmentalization of the modeled area. The objective of the modeling was not to pro- ject slopes because this massif was undergoing a progressive slow rupture. The objective of the modeling was to study the movement of the mass of rock and its progressive rupture caused by a shear zone.
The fall of the "new eve": a psychological Reading of women in love. The fall of the "new eve": a psychological Reading of women in love.
Irene R. da Silva
Ilha do Desterro , 2008,
Abstract: Man must either lead or be destroyed. Woman cannot lead. She can only be at one with man in the creative union, whilst he leads; or failing this, she can destroy. Lawrence As the novel opens, Gudrun, Ursula's younger sister, now twenty-five, has just returned home, and from her first words it is possible to detect that "the desire for destruction in the self" has already taken precedence over "every other desire" in her, for she expresses her disillusionment in life: she feels that everything fails to blossom and that she herself is caught in the fading process. Yet, although the forces of disintegration, of 'Putting assu nder , " are very strong in her, she reveals that "the living desire for positive creation" still exists for her, that she is still linked to humanity, that the "highly complex unit"1 formed by the male and female elements in herself has not yet been totally destroyed Man must either lead or be destroyed. Woman cannot lead. She can only be at one with man in the creative union, whilst he leads; or failing this, she can destroy. Lawrence As the novel opens, Gudrun, Ursula's younger sister, now twenty-five, has just returned home, and from her first words it is possible to detect that "the desire for destruction in the self" has already taken precedence over "every other desire" in her, for she expresses her disillusionment in life: she feels that everything fails to blossom and that she herself is caught in the fading process. Yet, although the forces of disintegration, of 'Putting assu nder , " are very strong in her, she reveals that "the living desire for positive creation" still exists for her, that she is still linked to humanity, that the "highly complex unit"1 formed by the male and female elements in herself has not yet been totally destroyed
EFFECT OF Crotalus durissus terrificus (LAURENTI, 1768) AND Bothrops jararaca (WIED, 1824) VENOMS ON THE EVOLUTION OF EHRLICH ASCITES TUMOR
R. J. da Silva
Journal of Venomous Animals and Toxins , 1996, DOI: 10.1590/s0104-79301996000200013
Abstract:
Cytokine profile on the ehrlich ascites tumor treated with Bothrops jararaca venom
R. J. da SILVA
Journal of Venomous Animals and Toxins , 2001, DOI: 10.1590/s0104-79302001000100012
Abstract:
Ferromagnetism in Dilute Magnetic Semiconductors
R. da Silva Neves,A. Ferreira da Silva,R. Kishore
Physics , 2010,
Abstract: We study the ferromagnetism of Ga1-xMnxAs by using a model Hamiltonian, based on an impurity band and the anti-ferromagnetic exchange interaction between the spins of Mn atoms and the charge carriers in the impurity band. Based on the mean field approach we calculate the spontaneous magnetization as a function of temperature and the ferromagnetic transition temperature as a function of the Mn concentration. The random distribution of Mn impurities is taken into account by Matsubara and Toyozawa theory of impurities in semiconductors. We compare our results with experiments and other theoretical findings.
De voca o para profiss o: organiza o sindical docente e identidade social do professor
Erlando da Silva Rêses
Sociedade e Estado , 2008, DOI: 10.1590/s0102-69922008000200012
Abstract:
cudaBayesreg: Parallel Implementation of a Bayesian Multilevel Model for fMRI Data Analysis
Adelino R. Ferreira da Silva
Journal of Statistical Software , 2011,
Abstract: Graphic processing units (GPUs) are rapidly gaining maturity as powerful general parallel computing devices. A key feature in the development of modern GPUs has been the advancement of the programming model and programming tools. Compute Unified Device Architecture (CUDA) is a software platform for massively parallel high-performance computing on Nvidia many-core GPUs. In functional magnetic resonance imaging (fMRI), the volume of the data to be processed, and the type of statistical analysis to perform call for high-performance computing strategies. In this work, we present the main features of the R-CUDA package cudaBayesreg which implements in CUDA the core of a Bayesian multilevel model for the analysis of brain fMRI data. The statistical model implements a Gibbs sampler for multilevel/hierarchical linear models with a normal prior. The main contribution for the increased performance comes from the use of separate threads for fitting the linear regression model at each voxel in parallel. The R-CUDA implementation of the Bayesian model proposed here has been able to reduce significantly the run-time processing of Markov chain Monte Carlo (MCMC) simulations used in Bayesian fMRI data analyses. Presently, cudaBayesreg is only configured for Linux systems with Nvidia CUDA support.
Computational Representation of White Matter Fiber Orientations
Adelino R. Ferreira da Silva
International Journal of Biomedical Imaging , 2013, DOI: 10.1155/2013/232143
Abstract: We present a new methodology based on directional data clustering to represent white matter fiber orientations in magnetic resonance analyses for high angular resolution diffusion imaging. A probabilistic methodology is proposed for estimating intravoxel principal fiber directions, based on clustering directional data arising from orientation distribution function (ODF) profiles. ODF reconstructions are used to estimate intravoxel fiber directions using mixtures of von Mises-Fisher distributions. The method focuses on clustering data on the unit sphere, where complexity arises from representing ODF profiles as directional data. The proposed method is validated on synthetic simulations, as well as on a real data experiment. Based on experiments, we show that by clustering profile data using mixtures of von Mises-Fisher distributions it is possible to estimate multiple fiber configurations in a more robust manner than currently used approaches, without recourse to regularization or sharpening procedures. The method holds promise to support robust tractographic methodologies and to build realistic models of white matter tracts in the human brain. 1. Introduction Diffusion magnetic resonance imaging (MRI) is an MRI method that is able to characterize the diffusion displacement of water molecules in structured tissues of the human brain [1]. The key idea behind diffusion MRI is that of anisotropic diffusion. In structured tissues water mobility is not always the same in all directions. Molecular motion is favored in directions aligned with bundles of parallel fibers, such as in the human brain’s white matter. The natural diffusion of water molecules can reveal in vivo microscopic details about the architecture of both normal and diseased tissues. White matter fiber tractography is commonly implemented using the principal diffusion direction of the diffusion tensor imaging (DTI) model [2]. Popular fiber tracking approaches, such as the streamline tracking algorithm [3], uses the DTI model to extract the orientation dependence of the diffusion probability density function (PDF) of water molecules. However, the standard single-tensor DTI model is based on a Gaussian diffusion assumption; thus unable to resolve crossing and splitting of fiber bundles. Extended tensor models for fiber tracking based on mixture of Gaussian densities [4] and multitensor models [5] have been proposed to enable detection of multiple orientation distribution function (ODF) maxima per voxel. On the other hand, several studies have shown that fiber tracking based on high angular
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