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Search Results: 1 - 10 of 81007 matches for " Mario Roberto;Silva "
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A bouncing ball model with two nonlinearities: a prototype for Fermi acceleration
Edson D. Leonel,Mario Roberto Silva
Physics , 2009,
Abstract: Some dynamical properties of a bouncing ball model under the presence of an external force modeled by two nonlinear terms are studied. The description of the model is made by use of a two dimensional nonlinear measure preserving map on the variables velocity of the particle and time. We show that raising the straight of a control parameter which controls one of the nonlinearities, the positive Lyapunov exponent decreases in the average and suffers abrupt changes. We also show that for a specific range of control parameters, the model exhibits the phenomenon of Fermi acceleration. The explanation of both behaviours is given in terms of the shape of the external force and due to a discontinuity of the moving wall's velocity.
Avalia??o genética de vacas e touros da ra?a Gir com base na produ??o de leite em diferentes estádios de lacta??o
Verneque, Rui da Silva;Martinez, Mario Luiz;Teodoro, Roberto Luiz;
Revista Brasileira de Zootecnia , 2000, DOI: 10.1590/S1516-35982000000400016
Abstract: the objective of this study was to evaluate the viability of using partial records of milk yield instead of the production accumulated at 305 days of lactation to obtain the predicted breeding values (bv). sires and cows ranked by bv using accumulated milk yield records at 90(t90), 150(t150) and 210(t210) days of lactation were compared with bv estimated by using production up to 305 days (t305). an animal model was used to estimate the animals bv including herd-year, season and age of calving, and genetic group as fixed effects and the animal, permanent environment and residual as random effects. heritability and repeatability estimates for t90, t150, t210 and t305 were 0.21±0.03 and 0.47±0.03; 0.23±0.03 and 0.50±0.03; 0.24±0.03 and 0.50±0.03; and 0.23±0.03 and 0.49±0,03, respectively. genetic correlations between t305 and t90, t150 and t210 were 0.92, 0.96 and 0.98, respectively. rank correlations between bv305 and bv90, bv150 and bv210 ranged from 0.83 to 0.97 and were smaller as production periods and percentage of selected or culled animals based on their bv were reduced. selecting the top 20% animals by bv305, 65, 76 and 87% of those animals would be selected if bv90, bv150 and bv210 were used, respectively. culling the bottom 20% animals by bv305, only 53, 68 and 83% would be culled if bv90, bv150 or bv210 were used, respectively. the results were similar between sires and cows. therefore, under a technical point of view, the use of partial records of milk yield, in a short period, could result in wrong decisions in the selection of the best or in the culling of the worst animals in the herd.
Avalia o genética de vacas e touros da ra a Gir com base na produ o de leite em diferentes estádios de lacta o
Verneque Rui da Silva,Martinez Mario Luiz,Teodoro Roberto Luiz
Revista Brasileira de Zootecnia , 2000,
Abstract: O objetivo deste trabalho foi avaliar a viabilidade técnica de se usar a produ o de leite em parte da lacta o, em vez da produ o acumulada até 305 dias, para obten o dos valores genéticos preditos (VG). Foram comparadas as classifica es de touros e vacas pelos seus VG para produ o de leite até 90(T90), 150(T150) e 210(T210) dias de lacta o, em rela o à classifica o, com base nos VG calculados, usando-se a produ o até 305(T305) dias. Adotou-se um modelo animal que incluiu os efeitos fixos de rebanho-ano, época, idade da vaca ao parto e grupo genético e os efeitos aleatórios do animal, do meio permanente e do resíduo. Estimativas de herdabilidade e repetibilidade para T90, T150, T210 e T305 foram 0,21±0,03 e 0,47±0,03; 0,23±0,03 e 0,50±0,03; 0,24±0,03 e 0,50±0,03; e 0,23±0,03 e 0,49±0,03, respectivamente. Correla es genéticas entre T305 e as produ es parciais T90, T150 e T210 foram 0,92; 0,96; e 0,98, respectivamente. Correla es de ordem entre os VG305 com VG90, VG150 e VG210 variaram de 0,83 a 0,97 e foram menores, quanto mais curto o período de produ o e menor o percentual de animais selecionados (descartados), segundo seus VG. Selecionando-se 20% dos animais de maior VG305, cerca de 65, 76 e 87% deles também seriam escolhidos, se fossem usados VG90, VG150 ou VG210, respectivamente. Descartando-se 20% dos animais de menor VG305, apenas cerca de 53, 68 e 83% também seriam eliminados, se VG90, VG150 ou VG210 fossem usados, respectivamente. Os resultados foram similares para vacas e touros. Concluiu-se que, sob o ponto de vista técnico, o uso da produ o de leite em parte da lacta o, em curto período, pode resultar em sérios erros na escolha dos melhores ou no descarte dos piores animais do rebanho.
Effect of rotary instrumentation and of the association of calcium hydroxide and chlorhexidine on the antisepsis of the root canal system in dogs
Soares, Janir Alves;Leonardo, Mario Roberto;Silva, Léa Assed Bezerra da;Tanomaru Filho, Mario;Ito, Izabel Yoko;
Brazilian Oral Research , 2006, DOI: 10.1590/S1806-83242006000200006
Abstract: this study aimed at evaluating the antisepsis of the root canal system (rcs) and periapical region (pr) provided by rotary instrumentation associated with chlorhexidine + calcium hydroxide as intracanal medicament. chronic periapical lesions were induced in 26 pre-molar roots in two dogs. after microbiological sampling, automatic instrumentation using the profile system and irrigation with 5.25% sodium hypochlorite solution, with a final rinse of 14.3% edta followed by profuse irrigation with physiological saline were carried out in 18 root canals. after drying the canals, a paste based on calcium hydroxide associated with a 2% chlorhexidine digluconate solution was placed inside them. after 21 days, the medication was removed, leaving the root canals empty and coronally sealed. after 96 hours, a final microbiological sample was obtained, followed by histomicrobiological processing by the brown & brenn method. eight untreated root canals represented the control group (c-g). based on the mann-whitney test at a confidence level of 5% (p < 0.05), the procedures of antisepsis used offered significant efficacy (p < 0.05) resulting in 100.0% of the canals free of microorganisms. in the c-g, an elevated incidence of various microbial morphotypes was confirmed in all sites of the rcs, with the presence of microbial colonies in the periapical region. in contrast, the experimental group showed a similar pattern of infection in the rcs, although less intense and a reduced level of periapical infection (p < 0.05). it was concluded that adequate instrumentation followed by the application of calcium hydroxide + chlorhexidine offered significant elimination of microorganisms.
Importance of bacterial endotoxin (LPS) in endodontics
Leonardo, Mario Roberto;Silva, Raquel Assed Bezerra da;Assed, Sada;Nelson-Filho, Paulo;
Journal of Applied Oral Science , 2004, DOI: 10.1590/S1678-77572004000200002
Abstract: new knowledge of the structure and biological activity of endotoxins (lps) has revolutionized concepts concerning their mechanisms of action and forms of inactivation. since the 1980's, technological advances in microbiological culture and identification have shown that anaerobic microorganisms, especially gram-negative, predominate in root canals of teeth with pulp necrosis and radiographically visible chronic periapical lesions. gram-negative bacteria not only have different factors of virulence and generate sub-products that are toxic to apical and periapical tissues, as also contain endotoxin (lps) on their cell wall. this is especially important because endotoxin is released during multiplication or bacterial death, causing a series of biological effects that lead to an inflammatory reaction and resorption of mineralized tissues. thus, due to the role of endotoxin in the pathogenesis of periapical lesions, we reviewed the literature concerning the biological activity of endotoxin and the relevance of its inactivation during treatment of teeth with pulp necrosis and chronic periapical lesion.
Correlation between parameters of electrophysiological, histomorphometric and sciatic functional index evaluations after rat sciatic nerve repair
Martins, Roberto Sergio;Siqueira, Mario Gilberto;Silva, Ciro Ferreira da;Plese, José Píndaro Pereira;
Arquivos de Neuro-Psiquiatria , 2006, DOI: 10.1590/S0004-282X2006000500010
Abstract: the rat sciatic nerve is a well-established model for the study of recovery from peripheral nerve injuries. traditional methods of assessing nerve regeneration after nerve injury and repair, such as electrophysiology and histomorphometry, despite widely used in neural regeneration experiments, do not necessarily correlate with return of motor and sensory functions. the aim of this experimental study is to investigate the possible correlation between several parameters of peripheral nerve regeneration after repair of sectioned sciatic nerve in wistar rat. a two-stage approach was used to obtain 17 parameters after electrophysiological, morphometric and sciatic functional index evaluations. pearson's correlation analysis was performed between these results. only two positives correlations between different classes of peripheral nerve assessments were noted, between sciatic functional index and proximal nerve fiber diameter (r=0.56, p<0.01) and between sciatic functional index and distal fiber diameter (r=0.50, p<0.01). the data presented in our study demonstrates that there is a poor correlation between the sciatic functional index and outcome measures of electrophysiological and morphometric evaluations.
Histological study of the effect of some irrigating solutions on bacterial endotoxin in dogs
Silva, Léa Assed Bezerra da;Leonardo, Mario Roberto;Assed, Sada;Tanomaru Filho, Mário;
Brazilian Dental Journal , 2004, DOI: 10.1590/S0103-64402004000200005
Abstract: the aim of this study was to evaluate, histopathologically, the effectiveness of mechanical preparation of root canals using different irrigating solutions in dog teeth filled with lps after pulpectomy. a total of 120 root canals of 6 mongrel dogs were filled with a solution of lps after pulpectomy. the irrigating solutions used were saline, 1, 2.5, and 5% sodium hypochlorite, and 2% chlorhexidine. no irrigation was used in the control group. the animals were sacrificed after 60 days and the teeth were fixed and demineralized. subsequently, serial 6-μm sections were stained with hematoxylin and eosin and mallory's trichrome for histopathological analysis and brown-brenn for verification of bacterial contamination. analysis showed that the inflammatory infiltrate was statistically less intense in the groups in which the root canals were irrigated with 5% sodium hypochlorite and 2% chlorhexidine. however, none of the irrigating solutions completely inactivated the harmful effects of lps. mechanical preparation associated with different irrigating solutions did not completely inactivate lps.
COAGULOPATHY IN DOGS INFECTED WITH Trypanosoma (Trypanozoon) evansi (STEEL, 1885) BALBIANI, 1888
DE LA RUE,MARIO L; SILVA,ROBERTO A S; DE CARLI,GERALDO A;
Parasitología al día , 1997, DOI: 10.4067/S0716-07201997000300005
Abstract: the authors studied the hematologic alterations of 14 dogs experimentally infected with trypanosoma (tripanozoon) evansi (steel, 1885) balbiani, 1888. the acute phase of parasitemia was characterized by a decrease in erythrocyte and platelet numbers, in mean corpuscular hemoglobin rate and in hematocrit, and by an increase in the rate of partial prothrombin activation time (p < 0.05). the presence of infection did not cause any alterations in mean corpuscular volume, hemoglobin levels, leukocyte numbers, prothrombin time, or plasma fibrinogen (p > 0.05)
Candidiasis invasoras en el paciente crítico adulto
Tobar A,Eduardo; Silva O,Francisco; Olivares C,Roberto; Gaete G,Pablo; Luppi N,Mario;
Revista chilena de infectología , 2011, DOI: 10.4067/S0716-10182011000100008
Abstract: invasive infections by candida strains are a relevant pathology in critically ill patients. candida should be considered where a high risk of infection is present for a critical early diagnosis. despite the incorporation of new drugs in the therapeutic armamentarium over the last decade, mortality remains high. the key in improving clinical outcomes of these patients are the use of early effective therapies that offer coverage against different strains of candida: c. albicans and non-albicans. recent international guidelines suggest empiric therapy with echinocandins in suspected invasive candidiasis in this patient population. this group of drugs adequately documented clinical efficacy and safe use in these patients. the emergence of new echinocandins could improve access to these drugs by reducing their cost.
COAGULOPATHY IN DOGS INFECTED WITH Trypanosoma (Trypanozoon) evansi (STEEL, 1885) BALBIANI, 1888
MARIO L DE LA RUE,ROBERTO A S SILVA,GERALDO A DE CARLI
Parasitología al día , 1997,
Abstract: The authors studied the hematologic alterations of 14 dogs experimentally infected with Trypanosoma (Tripanozoon) evansi (Steel, 1885) Balbiani, 1888. The acute phase of parasitemia was characterized by a decrease in erythrocyte and platelet numbers, in mean corpuscular hemoglobin rate and in hematocrit, and by an increase in the rate of partial prothrombin activation time (p < 0.05). The presence of infection did not cause any alterations in mean corpuscular volume, hemoglobin levels, leukocyte numbers, prothrombin time, or plasma fibrinogen (p > 0.05) Los autores estudiaran las alteraciones hematológicas de 14 perros experimentalmente infectados con Trypanosoma evansi (Steel, 1885) Balbiani, 1888. LA fase aguda se caracterizó por la disminución del número de eritrocitos, plaquetas y de la tasa de hemoglobina corpuscular media (CHCM), del hematocrito y por un aumento del índice de activación del tiempo de tromboplastina parcial (ATTP) (p < 0.05). La presencia de infección no causó alteraciones en el volumen corpuscular medio (VCM), en la tasa de hemoglobina, en el número de leucocitos, en el tiempo de protrombina (TP) y en el fibrinogeno plasmático (p > 0.05) Os autores estudiaram as alteracoes hematológicas de 14 caes experimentalmente infectados com Trypanosoma (Trypanozoon) evansi (Steel, 1885) Balbiani, 1888. A fase aguda da parasitemia caracterizou-se pela diminuicao do número de eritrocitos, das plaquetas, da taxa de hemoglobina corpuscular média (CHCM), do hematocrito, e pelo aumento do indice de ativacao do tempo de tromboplastina parcial (ATTP) (p < 0.05). A presenca da infeccao nao ocasionou alteracoes no volume corpuscular médio (VCM), na taxa de hemoglobina, no número de leucócitos, no tempo de protrombina (TP) e no fibrinogenio plamático (p > 0.05)
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