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Search Results: 1 - 10 of 277779 matches for " Ricardo C. Silva "
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On Cost Based Algorithm Selection for Problem Solving  [PDF]
Edilson F. Arruda, Fabrício Ourique, Anthony Almudevar, Ricardo C. Silva
American Journal of Operations Research (AJOR) , 2013, DOI: 10.4236/ajor.2013.35041
Abstract: This work proposes a novel framework that enables one to compare distinct iterative procedures with known rates of convergence, in terms of the computational effort to be employed to reach some prescribed vicinity of the optimal solution to a given problem of interest. An algorithm is introduced that decides between two competing algorithms, which algorithm makes the best use of the computational resources for some prescribed error. Several examples are presented that illustrate the trade-offs involved in such a choice and demonstrate that choosing an algorithm over another with a higher rate of convergence can be perfectly justifiable in terms of the overall computational effort.
Correctors for the Neumann problem in thin domains with locally periodic oscillatory structure
Marcone C. Pereira,Ricardo P. Silva
Mathematics , 2013,
Abstract: In this paper we are concerned with convergence of solutions of the Poisson equation with Neumann boundary conditions in a two-dimensional thin domain exhibiting highly oscillatory behavior in part of its boundary. We deal with the resonant case in which the height, amplitude and period of the oscillations are all of the same order which is given by a small parameter $\epsilon > 0$. Applying an appropriate corrector approach we get strong convergence when we replace the original solutions by a kind of first-order expansion through the Multiple-Scale Method.
The Current and Future Role of Drugs and Probiotics in the Management of Inflammatory Bowel Disease  [PDF]
Maricelma da Silva Soares de Souza, Sandra Maria Barbalho, Ricardo de Alvares Goulart, Antonely de Cássio Alves de Carvalho
Journal of Biosciences and Medicines (JBM) , 2015, DOI: 10.4236/jbm.2015.38008
Abstract: Inflammatory Bowel Disease (IBD) and other auto-inflammatory disorders are conditions caused by chronic and persistent intestinal inflammation, which is mainly represented by Ulcerative Colitis (UC) or Crohn’s Disease (CD), both of which typically arise as chronic inflammation of the gastrointestinal mucosa. Doctor’s main focus for treating IBD is the decrease on inflammation processes when the disease is active and promotes the maintenance of inflammation at normal levels. However, to deal with these two parameters is not easy, because the drugs usually used are related to several side effects and they are not totally effective to reduce inflammation and to keep the remission. Authors agree that the therapy approach should include drugs, dietary intervention and use of alternative substances as probiotics. The standard treatment approach for patients with CD and UC is traditionally done with the use of anti-inflammatory agents, like corticosteroids, mesalamine, immunomodulators such as azathioprine and methotrexate, and biologic agents such as infliximab and others. Probiotics are known as viable micro-organisms (or live microorganisms or live microbial dietary supplements) that may promote beneficial physiologic or therapeutic properties when used correctly. The interest in the role of these substances in improving human health is the reason of several researches. They may be used to help the immune system, to control gastro-intestinal infections and to prevent several diseases. Prebiotics, symbiotics, and probiotics may be helpful as adjuvants in the treatment of IBD. Probiotics are normally well-tolerated and are associated with few side effects which are undoubtedly important in the treatment of any disease.
Lycopene Supplementation Attenuates Oxidative Stress Parameters in the Plasma of Humans with Cad after Intense Exercise  [PDF]
Marília C. Araujo, Fernanda S. Soares, Merieli M. Ronsani, Luiz G. C. Rocha, Lilian C. Vieira, Luciano A. Silva, Tales de Carvalho, Magnus Benetti, Ricardo A. Pinho
Food and Nutrition Sciences (FNS) , 2011, DOI: 10.4236/fns.2011.24034
Abstract: To investigate the effects of moderate and intense exercise (ME,IE) and lycopene (L) supplementation on oxidative stress biomarkers in patients with CAD. Rehabilitation clinic.Thirty-two male volunteers with CAD (55.65 ? 2.27 years, 77.27 ? 3.95 kg, 171.9 ? 2.80 cm) were divided into four groups; ME-Placebo (n = 7), ME + L (n = 8), IE-Placebo (n = 8) and IE-L (n = 9). Blood samples (12 mL) were collected before supplementation (one cereal bars – 15 mg of syn-thetic lycopene) and exercise (45 min plus 15 min of stretching, 3/wk) and after five weeks of supplementation and 72 h after exercise. Nitrite/nitrate concentrations (NOx), lipoperoxidation (TBARS levels), protein carbonylation (PC) and superoxide dismutase (SOD) and catalase (CAT) activity were assessed in plasma. NOx decreased significantly in the ME-P, IE-P and ME-L groups at 72 h after exercise and increased in the IE-L 72 h after the last exercise session. The IE-L group demonstrated decreased TBARS at 72 h after the last exercise session. The level of PC increased only in EI-P at 72 h after the last exercise session, while only the EI-L group presented a reduction. SOD increased signifi-cantly in both placebo groups 72 h after the last exercise session and decreased in the ME-L group 72 h after in rela-tion to placebo groups. CAT increased in ME-P, IE-P and IE-L groups only at 72 h after the last exercise session. The lycopene supplementation attenuates some markers of oxidative stress associated with IE Lycopene also had dissimilar effects on some markers of oxidative stress in subjects undertaking ME versus IE.
Ergodic magnetic limiter for the TCABR
Silva, Elton C. da;Caldas, Iberê L.;Viana, Ricardo L.;
Brazilian Journal of Physics , 2002, DOI: 10.1590/S0103-97332002000100008
Abstract: in this work it is considered the effect of an ergodic magnetic limiter on the plasma confined in the tcabr tokamak. the poloidal distribution of the limiter currents is determined taking into account the toroidal geometry of this tokamak. the plasma equilibrium field is analytically obtained by solving the grad-schlüter-shafranov equation in polar toroidal coordinates. the perturbing limiter field is obtained as a vacuum field by solving the laplace equation. supposing the limiter action as a sequence of delta-function pulses, a symplectic map is derived by using a hamiltonian formulation for the perturbed field line. examples are given to illustrate the influence of this design on the topology of the perturbed field line structure.
Avalia??o da capacidade tamponante - um experimento participativo
Silva, César Ricardo;Simoni, José de Alencar;
Química Nova , 2000, DOI: 10.1590/S0100-40422000000300019
Abstract: the aim of this work is to show an experiment from which students can learn some of the main characteristics of buffer solutions. a mixture of some acid-base indicators, named as yamada's indicator, can be used to estimate ph values in an acid-base titration of a buffer, with good approximation. in the experiment it is also possible to verify the relationship between the buffer capacity and the concentrations and the molar ratio of the components of a nh3 / nh4+ buffer solution. the shortage of experiments associated with the relative small importance given to many aspects of buffer solutions, is now explored with simplicity. in the proposed experiments, students prepare buffer solutions by themselves, calculate the ph, understand how acid-base indicators act and learn how buffer solutions work through graph constructed by sharing experimental data.
Análise da rejei??o nos pacientes transplantados por anemia aplástica severa condicionados com ciclofosfamida ou a associa??o desta ao bussulfano
Silva, Lídice C. Lenz e;Pasquini, Ricardo;
Revista Brasileira de Hematologia e Hemoterapia , 2005, DOI: 10.1590/S1516-84842005000100004
Abstract: bone marrow transplantation is an effective therapy for severe aplastic anemia and is generally considered the preferable treatment for young patients who have an hla (human leukocyte antigen) identical sibling donor. recent studies report 55% to 80% extended survival. graft failure owing to rejection or others causes remains an important life-threatening complication following allogeneic bone marrow transplantation for aplastic anemia. it occurs in 55% to 60% of patients receiving hla identical transplants, using different immunosuppressive therapies before and after transplant. the bmt unit of federal university of paraná had 178 cases of saa transplants from 1993 to 2001 using either cyclophosphamide (cy) alone or associated with busulfan (cy+bu) for conditioning regimen. graft failure occurred in 39 of the cases. among patients conditioned with cy, 24 (46%) presented graft failure, of whom 3 (6%) suffered primary graft failures and 21 (40%) transient engraftment. among patients conditioned with bu+cy, 15 (12%) suffered graft failure, 4 (3%) primary graft failures and 11 (9%) transient engraftment. the patients conditioned with cy and experienced rejection had a survival of around 80%, because they underwent another transplantation or due to immunosuppressive treatment with cyclosporin a. the patients conditioned with bu+cy who suffered rejections had a survival of approximately 35%.
Virtual interpolation of discrete multi-objective programming solutions with probabilistic operation
Silva, Ricardo C.;Arruda, Edilson F.;Ourique, Fabrício O.;
Sba: Controle & Automa??o Sociedade Brasileira de Automatica , 2011, DOI: 10.1590/S0103-17592011000400005
Abstract: this work presents a novel framework to address the long term operation of a class of multi-objective programming problems. the proposed approach considers a stochastic operation and evaluates the long term average operating costs/profits. to illustrate the approach, a two-phase method is proposed which solves a prescribed number of k mono-objective problems to identify a set of k points in the pareto-optimal region. in the second phase, one searches for a set of non-dominated probability distributions that define the probability that the system operates at each point selected in the first phase, at any given operation period. each probability distribution generates a vector of average long-term objectives and one solves for the pareto-optimal set with respect to the average objectives. the proposed approach can generate virtual operating points with average objectives that need not have a feasible solution with an equal vector of objectives. a few numerical examples are presented to illustrate the proposed method.
Avalia o da capacidade tamponante - um experimento participativo
Silva César Ricardo,Simoni José de Alencar
Química Nova , 2000,
Abstract: The aim of this work is to show an experiment from which students can learn some of the main characteristics of buffer solutions. A mixture of some acid-base indicators, named as Yamada's indicator, can be used to estimate pH values in an acid-base titration of a buffer, with good approximation. In the experiment it is also possible to verify the relationship between the buffer capacity and the concentrations and the molar ratio of the components of a NH3 / NH4+ buffer solution. The shortage of experiments associated with the relative small importance given to many aspects of buffer solutions, is now explored with simplicity. In the proposed experiments, students prepare buffer solutions by themselves, calculate the pH, understand how acid-base indicators act and learn how buffer solutions work through graph constructed by sharing experimental data.
Ergodic magnetic limiter for the TCABR
Silva Elton C. da,Caldas Iberê L.,Viana Ricardo L.
Brazilian Journal of Physics , 2002,
Abstract: In this work it is considered the effect of an ergodic magnetic limiter on the plasma confined in the TCABR tokamak. The poloidal distribution of the limiter currents is determined taking into account the toroidal geometry of this tokamak. The plasma equilibrium field is analytically obtained by solving the Grad-Schlüter-Shafranov equation in polar toroidal coordinates. The perturbing limiter field is obtained as a vacuum field by solving the Laplace equation. Supposing the limiter action as a sequence of delta-function pulses, a symplectic map is derived by using a Hamiltonian formulation for the perturbed field line. Examples are given to illustrate the influence of this design on the topology of the perturbed field line structure.
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