221 resultados para Sparse Matrix
em Reposit
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This paper deals with approaches for sparse matrix substitutions using vector processing. Many publications have used the W-matrix method to solve the forward/backward substitutions on vector computer. Recently a different approach has been presented using dependency-based substitution algorithm (DBSA). In this paper the focus is on new algorithms able to explore the sparsity of the vectors. The efficiency is tested using linear systems from power systems with 118, 320, 725 and 1729 buses. The tests were performed on a CRAY Y MP2E/232. The speedups for a fast-forward/fast-backward using a 1729-bus system are near 19 and 14 for real and complex arithmetic operations, respectively. When forward/backward is employed the speedups are about 8 and 6 to perform the same simulations.
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SMase I, a 32 kDa sphingomyelinase found in Loxosceles laeta venom, is responsible for the major pathological effects of spider envenomation. This toxin has been cloned and functionally expressed as a fusion protein containing a 6 x His tag at its N-terminus to yield a 33 kDa protein [Fernandes-Pedrosa et al. (2002), Biochem. Biophys. Res. Commun. 298, 638 - 645]. The recombinant protein possesses all the biological properties ascribed to the whole L. laeta venom, including dermonecrotic and complement-dependent haemolytic activities. Dynamic light-scattering experiments conducted at 291 K demonstrate that the sample possesses a monomodal distribution, with a hydrodynamic radius of 3.57 nm. L. laeta SMase I was crystallized by the hanging-drop vapour-diffusion technique using the sparse-matrix method. Single crystals were obtained using a buffer solution consisting of 0.08 M HEPES and 0.9 M trisodium citrate, which was titrated to pH 7.5 using 0.25 M sodium hydroxide. Complete three-dimensional diffraction data were collected to 1.8 Angstrom at the Laboratorio Nacional de Luz Sincrotron (LNLS, Campinas, Brazil). The crystals belong to the hexagonal system ( space group P6(1) or P6(5)), with unit-cell parameters a = b = 140.6, c = 113.6 Angstrom. A search for heavy-atom derivatives has been initiated and elucidation of the crystal structure is currently in progress.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Pós-graduação em Biofísica Molecular - IBILCE
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A total of 350 commercial Bovans White laying hens were used to evaluate the association of carbohydrases and phytase in enriched diets and its effects on performance and egg quality of laying hens. The experiment used a randomized design with five treatments and seven replicates. The treatments were: 1. Positive control without added enzymes and without nutrient enrichment, 2. Negative control (NC) 1 with 1.5% and 6% AME (kcal/kg) enrichment for corn and soybean meal respectively, 2% crude protein (CP) enrichment, and digestible limiting digestible amino acids plus the full matrix for the phytase enzyme; 3. NC 2 with 1.5% and 6% AME (kcal/kg) enrichment, respectively, for corn and soybean meal and 2% crude protein (CP) enrichment, and digestible limiting amino acids plus the sparse matrix for the phytase enzyme, 4. NC 1 supplemented with 100 g ton(-1) carbohydrase and 30g ton(-1) phytase, 5. NC 2 supplemented with 100 g ton(-1) carbohydrase and 30g ton(-1) phytase. According to the results, the positive control treatments, NC1 and NC2, with or without enzyme supplementation, showed guaranteed performance for feed intake, egg yield, weight, egg loss and shell quality.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This paper describes a methodology for solving efficiently the sparse network equations on multiprocessor computers. The methodology is based on the matrix inverse factors (W-matrix) approach to the direct solution phase of A(x) = b systems. A partitioning scheme of W-matrix , based on the leaf-nodes of the factorization path tree, is proposed. The methodology allows the performance of all the updating operations on vector b in parallel, within each partition, using a row-oriented processing. The approach takes advantage of the processing power of the individual processors. Performance results are presented and discussed.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Endochondral calcification involves the participation of matrix vesicles (MVs), but it remains unclear whether calcification ectopically induced by implants of demineralized bone matrix also proceeds via MVs. Ectopic bone formation was induced by implanting rat demineralized diaphyseal bone matrix into the dorsal subcutaneous tissue of Wistar rats and was examined histologically and biochemically. Budding of MVs from chondrocytes was observed to serve as nucleation sites for mineralization during induced ectopic osteogenesis, presenting a diameter with Gaussian distribution with a median of 306 ± 103 nm. While the role of tissue-nonspecific alkaline phosphatase (TNAP) during mineralization involves hydrolysis of inorganic pyrophosphate (PPi), it is unclear how the microenvironment of MV may affect the ability of TNAP to hydrolyze the variety of substrates present at sites of mineralization. We show that the implants contain high levels of TNAP capable of hydrolyzing p-nitrophenylphosphate (pNPP), ATP and PPi. The catalytic properties of glycosyl phosphatidylinositol-anchored, polidocanol-solubilized and phosphatidylinositol-specific phospholipase C-released TNAP were compared using pNPP, ATP and PPi as substrates. While the enzymatic efficiency (k cat/Km) remained comparable between polidocanol-solubilized and membrane-bound TNAP for all three substrates, the k cat/Km for the phosphatidylinositol-specific phospholipase C-solubilized enzyme increased approximately 108-, 56-, and 556-fold for pNPP, ATP and PPi, respectively, compared to the membrane-bound enzyme. Our data are consistent with the involvement of MVs during ectopic calcification and also suggest that the location of TNAP on the membrane of MVs may play a role in determining substrate selectivity in this micro-compartment.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)