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Search Results: 1 - 10 of 380878 matches for " Rafael D. C.;Rezende "
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O ressurgimento da química de benzino com sililaril triflatos no contexto das rea??es de inser??o em liga??es sigma
Gallo, Rafael D. C.;Rezende, Hellenicy V.;Muzzi, Rozanna M.;Raminelli, Cristiano;
Química Nova , 2009, DOI: 10.1590/S0100-40422009000900037
Abstract: in this paper we gathered articles concerning insertion reactions of arynes, exclusively generated from 2-(trimethylsilyl)aryl triflates in the presence of fluoride ions, in substrates bearing nucleophilic and electrophilic portions separated by sigma bonds. accordingly, we stand out the great importance and versatility of such transformations in the preparation of highly functionalized aromatic systems, which are hardly synthesized in just one step for other methods.
Global phase portrait of a SIS model
Regilene D. S. Oliveira,Alex C. Rezende
Quantitative Biology , 2012,
Abstract: In the qualitative theory of ordinary differential equations, we can find many papers whose objective is the classification of all the possible topological phase portraits of a given family of differential system. Most of the studies rely on systems with real parameters and the study consists of outlining their phase portraits by finding out some conditions on the parameters. Here, we studied a susceptible-infected-susceptible (SIS) model described by the differential system $\dot{x}=-bxy-mx+cy+mk$, $\dot{y}=bxy-(m+c)y$, where $b$, $c$, $k$, $m$ are real parameters with $b \neq 0$, $m \neq 0$ (see Brauer (2002). Such system describes an infectious disease from which infected people recover with immunity against reinfection. The integrability of such system has already been studied by Nucci and Leach (2004) and Llibre and Valls (2008). We found out two different topological classes of phase portraits.
Efficacy of Drugs Used in Gastro-Oesophageal Reflux: Network Meta-Analysis  [PDF]
Rafael Bola?os-Díaz, Héctor Velarde-Criado, Erik Cóndor-Mori
Pharmacology & Pharmacy (PP) , 2013, DOI: 10.4236/pp.2013.42028
Abstract: Introduction: It is important to rank the clinical efficacy of different anti-reflux agents to promote their rational use. Objective: To combine the results of randomized clinical trials that have compared the incidence of symptoms related to gastro-oesophageal reflux (GER) with/without endoscopic evidence of oesophagitis in a network meta-analysis and thus rank the main anti-reflux therapies according to the magnitude of their clinical efficacy. Method: Inclusion criteria: 1) randomized controlled trials that compare anti-reflux agents (alginates (ALG), proton-pump inhibitors (PPI), H2 histamine receptor antagonists (H2RA), antacids (AA), gastrokinetics (GK)) in open designs as compared to placebo or in comparative designs (head-to-head); 2) outcome of interest measured in some scale representing the significant improvement of reflux symptoms; 3) GER diagnosis with/without oesophagitis endoscopic evidence. We collected available clinical trials for each one of the direct comparisons. The Odds Ratio (OR) was used additionally to calculating lnOR and its Standard Error (SE[lnOR]) to
Giving Flexibility to the Nelson-Siegel Class of Term Structure Models
Rafael Barros de Rezende
Revista Brasileira de Finan?as , 2011,
Abstract: his paper compares the interpolation abilities of nonparametric and parametric term structure models which are widely used by the main Central Banks of the world. Seeking the combination of smoothness and flexibility, a new Nelson-Siegel class model is introduced. It emerges as an extension of the Svensson (1994) and the five factor model proposed by De Rezende and Ferreira (2008) and Christensen, Diebold and Rudebusch (2008). It is shown the superiority of the smoothing spline model in interpolating the spot and forward rates as well as the advantage of the proposed model over the other Nelson-Siegel models. The superiority of the smoothing spline, however, comes with a cost: its instability in fitting the initial vertices of the term structure. The proposed model, on the other hand, exhibits the desirable properties of smoothness and flexibility, especially for the forward rates and the spot rates of medium and long terms.
Cirurgia de resgate no carcinoma de canal anal
Castro, Carlos A. C. Rangel de;Rezende, Viviane;Albagli, Rafael;Stev?o, Gilson Davi;Maltoni Jr., Luiz Augusto;Rondineli, Reinaldo;
Revista do Colégio Brasileiro de Cirurgi?es , 2002, DOI: 10.1590/S0100-69912002000600008
Abstract: background: carcinoma of the anal canal is a rare neoplasia, the treatment of wich is based on chemoradiation surgery is recommended alter treatment failure and recurrence. method: a retrospective review from october 1986 to september 2000 of all patients who underwent salvage surgery alter chemoradiotherapy failure. patients were reviewed as to time until recurrence and overall survival. results: ninety-three patients with epidermoid carcinoma of the anal canal were reviewed. twenty-one patients (22,5%) with residual or recurrent disease underwent salvage surgery. 19 patients (91%) underwent abdomino-perineal resection, 1 patient underwent pelvic exenteration and local resection was performed in 1 patient. there was no operative mortality. the overall survival was 24 months. conclusions: salvage surgical resection for anal canal carcinoma can be expected te yieid a number of survivors from residual/recurrent disease.
Estudo preliminar do vermicomposto produzido a partir de lodo de esgoto doméstico e solo
Silva, P. R. D;Landgraf, M. D;Zozolotto, T. C;Rezende, M. O. O;Pelatti, I;
Eclética Química , 2010, DOI: 10.1590/S0100-46702010000300005
Abstract: domestic waste, a residue generated during sewage treatments, can be stabilized by many chemical, physical and biological processes. however, the stabilized waste (biosoil) currently lacks proper disposal alternatives. a new and promising disposal method is called farm recycling. the use of vermicomposting has shown to be useful as a mean to stabilize domestic waste. the biosoil achieved through this method exhibits high humidity-retaining capacity, good c/n relationship, as well as a satisfactory percentage of humic acid, thus being able to be incorporated into the soil as a conditioner and fertilizer.
Global phase portraits of quadratic polynomial differential systems with a semi-elemental triple node
Joan C. Artés,Alex C. Rezende,Regilene D. S. Oliveira
Mathematics , 2012, DOI: 10.1142/S021812741350140X
Abstract: Planar quadratic differential systems occur in many areas of applied mathematics. Although more than one thousand papers have been written on these systems, a complete understanding of this family is still missing. Classical problems, and in particular, Hilbert's 16th problem, are still open for this family. In this article we make a global study of the family QTN of all real quadratic polynomial differential systems which have a semi-elemental triple node (triple node with exactly one zero eigenvalue). This family modulo the action of the affine group and time homotheties is three-dimensional and we give its bifurcation diagram with respect to a normal form, in the three-dimensional real space of the parameters of this form. This bifurcation diagram yields 28 phase portraits for systems in QTN counting phase portraits with and without limit cycles. Algebraic invariants are used to construct the bifurcation set. The phase portraits are represented on the Poincar\'e disk. The bifurcation set is not only algebraic due to the presence of a surface found numerically. All points in this surface correspond to connections of separatrices.
The geometry of quadratic polynomial differential systems with a finite and an infinite saddle-node (A,B)
Joan C. Artés,Alex C. Rezende,Regilene D. S. Oliveira
Mathematics , 2013, DOI: 10.1142/S0218127414500448
Abstract: The goal is to make a global study of the family QsnSN of all real quadratic polynomial differential systems which have a finite semi-elemental saddle-node and an infinite saddle-node formed by the collision of two infinite singular points. This family can be divided into three different subfamilies, all of them with the finite saddle-node in the origin of the plane with the eigenvectors on the axes and (A) with the infinite saddle-node in the horizontal axis, (B) with the infinite saddle-node in the vertical axis and (C) with the infinite saddle-node in the bisector of the first and third quadrants. These three subfamilies modulo the action of the affine group and time homotheties are three-dimensional and we give their bifurcation diagram with respect to a normal form, in the three-dimensional real space of the parameters of these forms. In this paper we provide the complete study of the geometry of the first two families, (A) and (B). The bifurcation diagram for the subfamily (A) yields 29 phase portraits for systems in QsnSN(A) counting phase portraits with and without limit cycles, while the bifurcation diagram for the subfamily (B) yields 16 phase portraits for systems in QsnSN(B) under the same conditions. Case (C) will yield quite more cases and will have an independent paper in short. Algebraic invariants are used to construct the bifurcation set. The phase portraits are represented on the Poincar\'e disk. The bifurcation set of QsnSN(A) is not only algebraic due to the presence of a surface found numerically. All points in this surface correspond to connections of separatrices.
Produ??o de Madeira Roli?a para Serraria de Pinus taeda no Sul do Brasil: Abordagem Experimental
Sanquetta,Carlos R.; Rezende,Alba V.; Gaiad,Débora; Schaaf,Luciano B.; Zampier,Ana C.;
Silva Lusitana , 2001,
Abstract: this paper evaluates the effects of initial plant spacing on the round-wood yield for saw timber in loblolly pine plantations in southern brazil. five initial densities were compared: (1) 2.5 m x 1.2 m; (2) 2.5 m x 2.0 m; (3) 2.5 m x 2.8 m; (4) 2.5 m x 3.6 m; and (5) 2.5 m x 4.4 m. data came from a randomized blocks experiment established in a brazilian forestry company. the experiment was analyzed through anova and tukey's test. graphical analysis was also performed to evaluate the impact of five thinning regimes: (1): a single final cut at age 15 without thinning; (2) a single final cut age 20 without thinning; (3) systematic thinning at age 9 and final cut at age 20; (4) selective thinning at ages 9 and 15 and final cut at age 20; and (5) systematic cut combined with selective thinning at age 9, selective thinning at age 15 and final cut at age 20. the results revealed differences (p<0.01) among plant densities. saw timber yield gradually increased with decreasing plant density, but remarkable differences were noticed for the two extreme treatments. the densities 2.5 m x 4.4 m and 2.5 m x 3.6 m, non-significantly different one another, were those of better performance. simulation analysis, however, indicated that density effect may be minimized for a longer period of time, mainly because of the effect of thinning regimes.
Lamina de irriga??o e aplica??o de CO2 na produ??o de piment?o cv. Mayata, em ambiente protegido
Furlan, Raquel A.;Rezende, Fátima C.;Alves, Dálcio Ricardo B.;Folegatti, Marcos Vinícius;
Horticultura Brasileira , 2002, DOI: 10.1590/S0102-05362002000400007
Abstract: the effect of different irrigation water depth applications and the atmosphere enrichment with co2 was evaluated. the experiment was carried out with sweet pepper (cultivar mayata) in two similar plastic greenhouses in piracicaba, brazil. in one of them, co2 was applied with irrigation water, increasing the co2 concentration in the atmosphere to 800 mmolco2/mol and in the other greenhouse the irrigation water was not enriched with co2. in each greenhouse four irrigation water depths were applied, corresponding to 60; 80; 100 and 120% of a reduced pan evaporation (rpa), in a complete randomized block design with ten replications. the co2 was injected into irrigation pipeline during a period of 40 minutes. fruits were harvested from ten selected plants, after 90 days of transplanting, evaluating fruit number, length, diameter, pulp thickness, weight and yield (kg/ha). the effect of different irrigation water depths was observed for length, pulp thickness and fruit number per plant in the greenhouse with co2 application. in the greenhouse with co2 enrichment and irrigation water depths corresponding to 100% of rpa, differences were observed in length, pulp thickness, fruits numbers per plant and yield of 7.0%, 4.5%, 35.0% and 38.4%, respectively. on the other hand, in the greenhouse without co2 application, different water depth applications did not affect any parameter. all analyzed parameters presented better results in the greenhouse with co2 enrichment, except for the fruit pulp thickness. the co2 application in the plastic greenhouse resulted in increased length, diameter, fruit number per plant, weight and yield of 12.4%, 11.9%, 21.4%, 20.0% and 51,3%, respectively.
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