Ricardo Rosa | Universidade de São Paulo (original) (raw)

Papers by Ricardo Rosa

R ep ro d u ced with p erm ission o f the copyright ow ner. Further reproduction prohibited w ith... more R ep ro d u ced with p erm ission o f the copyright ow ner. Further reproduction prohibited w ithout p erm ission.

Resumo: Neste artigo e apresentada a ferramenta Planager, um jogo para apoio no treinamento de ge... more Resumo: Neste artigo e apresentada a ferramenta Planager, um jogo para apoio no treinamento de gerencia de projetos de software. O jogo foi desenvolvido para auxiliar gerentes de projeto iniciantes e experientes a entenderem os conceitos envolvidos em suas atividades, atraves de um jogo interativo, baseado em cenarios e no PMBOK. Esta versao suporta inicialmente as principais atividades de planejamento presentes no PMBOK. Este artigo tambem apresenta os principais desafios identificados durante o desenvolvimento e algumas propostas de evolucoes para a ferramenta. Abstract: In this paper, we present Planager, a game developed to support software project management training. It is designed to help novel and experienced project managers to understand the concepts involved in the project management activity, through an interactive and scenario-based game. The game was initially developed to support the main planning activities according to the PMBOK. This paper also presents the challen...

Journal of Coloproctology, 2017

Objective: For decades, sphincter reconstruction after fistulectomy or fistulotomy was technicall... more Objective: For decades, sphincter reconstruction after fistulectomy or fistulotomy was technically forbidden, alleging various motivations (inflamed tissue, fibrosis, residual infection, high wound dehiscence rates, high recurrence rate etc). We present here the results obtained ina3yearretrospective study where fistulotomy and primary end-to-end sphincteroplasty with a modified technique were used to treat cryptogenic anal fístulas. Method: This is a retrospective study. All patients were operated by a single surgeon (UM), with the same technique, fistulotomy associated to a fine excision of fístula tract tissue and primary end-to-end sphincteroplasty (of IAS, EAS or both), and a small anal mucosal flap to close the internal fistulous opening. All patients had a diagnosis of intersphincteric or trans-sphincteric perianal fístulas (low or high-no suprasphincteric fístulas were included in this study);all patients were submitted to a preoperative Pelvic MRI, anorectal manometry and colonoscopy. The Wexner Incontinence Score was calculated preoperatively and postoperatively for all patient. All were followed up as outpatients at 7 days, 1 month, 3 and 6 months after surgery. Results: 37 patients were studied, 30 males and 7 females, mean age 40,97 (19-67). 12 patients were diagnosed with intersphincteric fístulas, 25 with transphincteric (12 anterior and 25 posterior fístulas), with 16 complex fístulas and 11 single tract fístulas. 1 patient related preoperative mild incontinence (resolved after surgery). Postoperative complications included 6 patients with delayed cicatrisation,1 postoperative (PO4) bleeding, 2 perianal dermatitis, 1 partial mucosal dehiscence and 1 anal profile deformity (resulting in a mild temporary fecal incontinence). No recurrences were observed during follow up. Conclusion: Fistulotomy and primary end-to-end sphincteroplasty is a safe surgical strategy to treat anal fístulas with very low complication rate. More studies are needed to asses the long term efficacy of this technique, but the early results are promising.

Journal of Coloproctology, 2017

RESUMO: A constipação intestinal crônica é um termo que representa sintomas de diferentes etiolog... more RESUMO: A constipação intestinal crônica é um termo que representa sintomas de diferentes etiologias e fisiopatologias, com sua prevalência variando de 2 a 30 % da população ocidental. Não existe uma definição única para constipação, motivo este que leva a uma grande discrepância na condução propedêutica e terapêutica desta afecção. Recentemente, em um consenso de especialistas, foram postulados alguns critérios para a sua definição (critérios de Roma II).Dentre vários exames para a avaliação da constipação, a manometria ano retal é o mais utilizado. OBJETIVO O objetivo deste trabalho é de realizar uma revisão na literatura da contribuição da manometria ano retal na avaliação de pacientes constipados, assim como avaliar retrospectivamente os pacientes, com diagnóstico de constipação crônica, que foram submetidos a este exame. MATERIAL E MÉTODOS Foram avaliados, retrospectivamente, 49 pacientes, com queixas de constipação, enviados para realização de manometria ano retal e testes de sensibilidade, capacidade e expulsão de balão intra retal. RESULTADOS Foi obtido como resultado um amplo predomínio do sexo feminino com 84,61% dos pacientes adultos(39).Foram avaliados 10 crianças/adolescentes(média de idade de 8,8 anos), com suspeita de megacólon congênito, apresentando um predomínio do sexo masculino(77,77%).Observamos: pressão de repouso aumentada em 09 pacientes e diminuída em 02; pressão de contração aumentada em 08 e diminuída em 03; zona de alta pressão diminuída em 04 ; sensibilidade ("threshold") aumentada em 08 e diminuída em 16; capacidade retal aumentada em 11 e diminuída em 05; contração muscular paradoxal ao esforço para evacuar em 07 ; teste de expulsão do balão negativo em 11 ; reflexo inibitório reto anal negativo em 05 pacientes e inconclusivo em 01. No grupo de pacientes com suspeita de megacólon congênito 08 tiveram a confirmação com reflexo inibitório negativo. CONCLUSÃO Baseados na revisão da literatura e nos nossos resultados, concluímos que os achados da manometria ano retal modificam a conduta no paciente constipado, podendo ser sugerido que esta avaliação seja realizada inicialmente em todos estes pacientes.

Journal of Research in Dentistry, 2014

AIM: The aims of this study were to assess the penetration of two endodontic sealers (salicylate ... more AIM: The aims of this study were to assess the penetration of two endodontic sealers (salicylate and epoxy resin-based sealers) into dentinal tubules using CLSM; and to evaluate the bacterial leakage of roots filled with the same sealers associated with gutta-percha. MATERIAL AND METHODS: For sealer penetrability assessment, thirty bovine roots were instrumented and divided into three groups: AHP: EDTA + filling with AH Plus and gutta-percha (n=10), MTAF: EDTA + filling with MTA Fillapex and gutta-percha (n=10), control group: canals were not irrigated with EDTA and were filled with gutta-percha and AH Plus (n=5) or MTA Fillapex (n=5). Rhodamine B was added to the sealers in order to provide adequate fluorescence. The roots were transversely sectioned 3mm from the apex to enable CLSM analysis. Leakage was evaluated for turbidity of the broth in a split chamber model system for 30 days, using Enterococcus faecalis as a microbial marker. Thirty roots were instrumented and divided in f...

Brazilian Journal of Veterinary Research and Animal Science, 2008

Foram estudadas e comparadas as densidades neuronais do córtex cerebral de três raças de cães, co... more Foram estudadas e comparadas as densidades neuronais do córtex cerebral de três raças de cães, com tipos constitucionais e aptidões funcionais característicos e distintos entre si. Dos encéfalos foram retirados fragmentos das diferentes áreas do córtex cerebral, correspondentes ao sistema límbico, visual, auditiva, motor, paladar, olfato e à área somestésica. Através de contagem visual-manual, foram buscados dados comparativos, entre áreas cerebrais versus raça associando tipos constitucionais versus aptidão funcional. Os fatores raças, áreas funcionais e hemisférios cerebrais podem ser variáveis dependentes entre si, pois foram encontradas diferenças estatisticamente significativas em valores correspondentes à média de densidade de neurônios das áreas estudadas nas diferentes raças, bem como entre os hemisférios cerebrais. Os resultados permitem concluir que a distribuição quantitativa de neurônios nas diferentes áreas corticais estudadas mostra diferenças significativas que estabe...

PSICOLOGIA, 2013

O estudo tem como objectivo descrever a utilização de serviços de saúde para informação, prevençã... more O estudo tem como objectivo descrever a utilização de serviços de saúde para informação, prevenção e teste do VIH por parte de homens gays em Portugal e identificar factores associados a ter efectuado o teste VIH em diferentes serviços. Para este estudo de abordagem participativa foi aplicado um inquérito por questionário a 1046 homens gays. Cerca de 27% dos participantes refere que recorreu ao CAD para obter informação sobre VIH/sida. Cerca de 83% recebeu gratuitamente preservativos no último ano. A maioria (88%) já efectuou o teste do VIH. Destes, 74% realizou­‑o no SNS, 22.5% num serviço privado e 6.5% numa ONG, verificando­‑se diferenças significativas quanto à idade, escolaridade, rendimento e nacionalidade. Os resultados indicam uma utilização dos serviços de saúde para informação, prevenção e teste do VIH pela maioria dos participantes. No entanto, é importante continuar a desenvolver esforços para promover a utilização dos serviços, em especial pelos grupos desta população q...

Journal of Dynamics and Differential Equations, 2003

A class of nonlinear parabolic partial differential equations is considered, and an exact finite ... more A class of nonlinear parabolic partial differential equations is considered, and an exact finite dimensional feedback control law is designed in order to force the systems to behave in a prescribed way. The feedback law is obtained via inertial manifold theory by reducing the system to finite dimensions. The control achieved is exact, as opposed to approximate, as obtained in

Foundations of Computational Mathematics, 1997

Abstract. Using inertial manifold theory, a finite-dimensional feedback controller is constructed... more Abstract. Using inertial manifold theory, a finite-dimensional feedback controller is constructed for a nonlinear parabolic partial differential equation so that the dynamics of the closed-loop system is close in a weighted C1-metric for the vector fields to a finite ...

Computers in Agriculture and Natural Resources, 23-25 July 2006, Orlando Florida

... João Rolim1, Pedro Godinho1, Bruno Sequeira1, Ricardo Rosa1, Paula Paredes1 and LuisSantos Pe... more ... João Rolim1, Pedro Godinho1, Bruno Sequeira1, Ricardo Rosa1, Paula Paredes1 and LuisSantos Pereira1 1 Agricultural Engineering Research Center, ISA, UTL ... Thus, three different components were built: a graphic user interface (GUI), a mathematical model and a database ...

2009 39th IEEE Frontiers in Education Conference, 2009

Abstract The premises considered by this work are that projects development in graduate courses i... more Abstract The premises considered by this work are that projects development in graduate courses is important for knowledge consolidation. However, one of the problems is that, usually, students are not prepared to manage and to be managed. This situation causes ...

Physica D: Nonlinear Phenomena, 2004

Nonlinearity, 1998

The energy equation approach used to prove the existence of the global attractor by establishing ... more The energy equation approach used to prove the existence of the global attractor by establishing the so-called asymptotic compactness property of the semigroup is considered, and a general formulation that can handle a number of weakly damped hyperbolic equations and parabolic equations on either bounded or unbounded spatial domains is presented. As examples, three specific and physically relevant problems are considered, namely the flows of a second-grade fluid, the flows of a newtonian fluid in an infinite channel past an obstacle, and a weakly damped, forced Korteweg-de Vries equation on the whole line. Contents 1. Introduction 2. Asymptotic Compactness 3. Abstract Energy Equations 4. Applications 4.1. Fluids of Second Grade 4.2. Flows Past an Obstacle 4.3. Weakly Damped, Forced Korteweg-de Vries Equation References

Nonlinear Analysis: Theory, Methods & Applications, 1998

We extend previous results on the existence of the global attractor for the 2D Navier-Stokes equa... more We extend previous results on the existence of the global attractor for the 2D Navier-Stokes equations on some unbounded domains in the sense that the forcing term need not lie in any weighted space nor is the boundary of the domain required to be smooth. The existence of the global attractor is obtained on arbitrary open sets such that the Poincaré inequality holds and for forces in the natural dual space V. The proof is based on the energy equation and the concept of asymptotic compactness. An estimate of the Hausdorff and fractal dimensions of the attractor is also given.

Journal of Esthetic and Restorative Dentistry, 2007

Background: Many post systems are available to clinicians, yet no consensus exists about which on... more Background: Many post systems are available to clinicians, yet no consensus exists about which one is better in restoring endodontically treated teeth. Purpose: This study evaluated the fracture strength of teeth with flared canals and restored with two fiber-reinforced resin systems (glass fiber: FRC Postec [Ivoclar Vivadent, Schaan, Liechtenstein]; quartz fiber: D.T. Light-Post [Bisco Dental Products, Schaumburg, IL, USA]), and one custom cast base metal (Ni-Cr) post and core system. Methods: Thirty anterior teeth had their crowns removed below the cemento-enamel junction and were endodontically treated. The canals were prepared for post fixation, and the canal walls were flared using a taper diamond bur. The prepared roots were randomly divided into three groups according to the post system. All posts were cemented with an adhesive resin cement. For the fiber-reinforced resin posts, cores were built up using microhybrid composite. Metallic crowns were luted using zinc phosphate cement. Specimens were loaded at 45 degrees in a universal testing machine at a crosshead speed of 0.5 mm/min until failure. The mode of failure was classified as repairable or nonrepairable. Results: Teeth restored with cast posts had fracture strength twice that of teeth restored with resin posts. Fiber-reinforced resin posts failed at a compressive force comparable to clinical conditions, but all failures were repairable. Conclusion: Fracture strength and mode of failure in anterior teeth with flared canals varied according to the type of post used to support a crown. CLINICAL SIGNIFICANCE Under the conditions of this study, cast posts are preferable to restore endodontically treated teeth with flared canals and no ferrule.

Journal of Dynamics and Differential Equations, 1995

In this work, we show that a strongly continuous semigroup generated by a normal operator N is co... more In this work, we show that a strongly continuous semigroup generated by a normal operator N is conjugate to the semigroup generated by the real part of N , provided zero is not an eigenvalue of the real part of N. We also show that in case N satisfies a certain sectorial property, the homeomorphism establishing the conjugacy, as well as its inverse, is locally Hölder continuous. Moreover, in case N satisfies the sectorial property and the real part of N has a pure point spectrum with an at most countable number of eigenvalues, the homeomorphism and its inverse are Lipschitz continuous.

Discrete and Continuous Dynamical Systems - Series B, 2008

We provide an analysis of the error in approximating Lyapunov exponents of dissipative PDEs on in... more We provide an analysis of the error in approximating Lyapunov exponents of dissipative PDEs on inertial manifolds using QR techniques. The reduction in the number of modes needed for an inertial form facilitates the error analysis. Numerical computations on the Kuramoto-Sivashinsky equation illustrate the results.

Discrete and Continuous Dynamical Systems, 2003

An extension to the nonautonomous case of the energy equation method for proving the existence of... more An extension to the nonautonomous case of the energy equation method for proving the existence of attractors for noncompact systems is presented. A suitable generalization of the asymptotic compactness property to the nonautonomous case, termed uniform asymptotic compactness, is given, and conditions on the energy equation associated with an abstract class of equations that assure the uniform asymptotic compactness are obtained. This general formulation is then applied to a nonautonomous Navier-Stokes system on an infinite channel past an obstacle, with time-dependent forcing and boundary conditions, and to a nonautonomous, weakly damped, forced Korteweg-de Vries equation on the real line.

Discrete and Continuous Dynamical Systems, 2003

Discrete & Continuous Dynamical Systems - A, 2010

The three-dimensional incompressible Navier-Stokes equations are considered along with its weak g... more The three-dimensional incompressible Navier-Stokes equations are considered along with its weak global attractor, which is the smallest weakly compact set which attracts all bounded sets in the weak topology of the phase space of the system (the space of square-integrable vector fields with divergence zero and appropriate periodic or no-slip boundary conditions). A number of topological properties are obtained for certain regular parts of the weak global attractor. Essentially two regular parts are considered, namely one made of points such that all weak solutions passing through it at a given initial time are strong solutions on a neighborhood of that initial time, and one made of points such that at least one weak solution passing through it at a given initial time is a strong solution on a neighborhood of that initial time. Similar topological results are obtained for the family of all trajectories in the weak global attractor.

R ep ro d u ced with p erm ission o f the copyright ow ner. Further reproduction prohibited w ith... more R ep ro d u ced with p erm ission o f the copyright ow ner. Further reproduction prohibited w ithout p erm ission.

Resumo: Neste artigo e apresentada a ferramenta Planager, um jogo para apoio no treinamento de ge... more Resumo: Neste artigo e apresentada a ferramenta Planager, um jogo para apoio no treinamento de gerencia de projetos de software. O jogo foi desenvolvido para auxiliar gerentes de projeto iniciantes e experientes a entenderem os conceitos envolvidos em suas atividades, atraves de um jogo interativo, baseado em cenarios e no PMBOK. Esta versao suporta inicialmente as principais atividades de planejamento presentes no PMBOK. Este artigo tambem apresenta os principais desafios identificados durante o desenvolvimento e algumas propostas de evolucoes para a ferramenta. Abstract: In this paper, we present Planager, a game developed to support software project management training. It is designed to help novel and experienced project managers to understand the concepts involved in the project management activity, through an interactive and scenario-based game. The game was initially developed to support the main planning activities according to the PMBOK. This paper also presents the challen...

Journal of Coloproctology, 2017

Objective: For decades, sphincter reconstruction after fistulectomy or fistulotomy was technicall... more Objective: For decades, sphincter reconstruction after fistulectomy or fistulotomy was technically forbidden, alleging various motivations (inflamed tissue, fibrosis, residual infection, high wound dehiscence rates, high recurrence rate etc). We present here the results obtained ina3yearretrospective study where fistulotomy and primary end-to-end sphincteroplasty with a modified technique were used to treat cryptogenic anal fístulas. Method: This is a retrospective study. All patients were operated by a single surgeon (UM), with the same technique, fistulotomy associated to a fine excision of fístula tract tissue and primary end-to-end sphincteroplasty (of IAS, EAS or both), and a small anal mucosal flap to close the internal fistulous opening. All patients had a diagnosis of intersphincteric or trans-sphincteric perianal fístulas (low or high-no suprasphincteric fístulas were included in this study);all patients were submitted to a preoperative Pelvic MRI, anorectal manometry and colonoscopy. The Wexner Incontinence Score was calculated preoperatively and postoperatively for all patient. All were followed up as outpatients at 7 days, 1 month, 3 and 6 months after surgery. Results: 37 patients were studied, 30 males and 7 females, mean age 40,97 (19-67). 12 patients were diagnosed with intersphincteric fístulas, 25 with transphincteric (12 anterior and 25 posterior fístulas), with 16 complex fístulas and 11 single tract fístulas. 1 patient related preoperative mild incontinence (resolved after surgery). Postoperative complications included 6 patients with delayed cicatrisation,1 postoperative (PO4) bleeding, 2 perianal dermatitis, 1 partial mucosal dehiscence and 1 anal profile deformity (resulting in a mild temporary fecal incontinence). No recurrences were observed during follow up. Conclusion: Fistulotomy and primary end-to-end sphincteroplasty is a safe surgical strategy to treat anal fístulas with very low complication rate. More studies are needed to asses the long term efficacy of this technique, but the early results are promising.

Journal of Coloproctology, 2017

RESUMO: A constipação intestinal crônica é um termo que representa sintomas de diferentes etiolog... more RESUMO: A constipação intestinal crônica é um termo que representa sintomas de diferentes etiologias e fisiopatologias, com sua prevalência variando de 2 a 30 % da população ocidental. Não existe uma definição única para constipação, motivo este que leva a uma grande discrepância na condução propedêutica e terapêutica desta afecção. Recentemente, em um consenso de especialistas, foram postulados alguns critérios para a sua definição (critérios de Roma II).Dentre vários exames para a avaliação da constipação, a manometria ano retal é o mais utilizado. OBJETIVO O objetivo deste trabalho é de realizar uma revisão na literatura da contribuição da manometria ano retal na avaliação de pacientes constipados, assim como avaliar retrospectivamente os pacientes, com diagnóstico de constipação crônica, que foram submetidos a este exame. MATERIAL E MÉTODOS Foram avaliados, retrospectivamente, 49 pacientes, com queixas de constipação, enviados para realização de manometria ano retal e testes de sensibilidade, capacidade e expulsão de balão intra retal. RESULTADOS Foi obtido como resultado um amplo predomínio do sexo feminino com 84,61% dos pacientes adultos(39).Foram avaliados 10 crianças/adolescentes(média de idade de 8,8 anos), com suspeita de megacólon congênito, apresentando um predomínio do sexo masculino(77,77%).Observamos: pressão de repouso aumentada em 09 pacientes e diminuída em 02; pressão de contração aumentada em 08 e diminuída em 03; zona de alta pressão diminuída em 04 ; sensibilidade ("threshold") aumentada em 08 e diminuída em 16; capacidade retal aumentada em 11 e diminuída em 05; contração muscular paradoxal ao esforço para evacuar em 07 ; teste de expulsão do balão negativo em 11 ; reflexo inibitório reto anal negativo em 05 pacientes e inconclusivo em 01. No grupo de pacientes com suspeita de megacólon congênito 08 tiveram a confirmação com reflexo inibitório negativo. CONCLUSÃO Baseados na revisão da literatura e nos nossos resultados, concluímos que os achados da manometria ano retal modificam a conduta no paciente constipado, podendo ser sugerido que esta avaliação seja realizada inicialmente em todos estes pacientes.

Journal of Research in Dentistry, 2014

AIM: The aims of this study were to assess the penetration of two endodontic sealers (salicylate ... more AIM: The aims of this study were to assess the penetration of two endodontic sealers (salicylate and epoxy resin-based sealers) into dentinal tubules using CLSM; and to evaluate the bacterial leakage of roots filled with the same sealers associated with gutta-percha. MATERIAL AND METHODS: For sealer penetrability assessment, thirty bovine roots were instrumented and divided into three groups: AHP: EDTA + filling with AH Plus and gutta-percha (n=10), MTAF: EDTA + filling with MTA Fillapex and gutta-percha (n=10), control group: canals were not irrigated with EDTA and were filled with gutta-percha and AH Plus (n=5) or MTA Fillapex (n=5). Rhodamine B was added to the sealers in order to provide adequate fluorescence. The roots were transversely sectioned 3mm from the apex to enable CLSM analysis. Leakage was evaluated for turbidity of the broth in a split chamber model system for 30 days, using Enterococcus faecalis as a microbial marker. Thirty roots were instrumented and divided in f...

Brazilian Journal of Veterinary Research and Animal Science, 2008

Foram estudadas e comparadas as densidades neuronais do córtex cerebral de três raças de cães, co... more Foram estudadas e comparadas as densidades neuronais do córtex cerebral de três raças de cães, com tipos constitucionais e aptidões funcionais característicos e distintos entre si. Dos encéfalos foram retirados fragmentos das diferentes áreas do córtex cerebral, correspondentes ao sistema límbico, visual, auditiva, motor, paladar, olfato e à área somestésica. Através de contagem visual-manual, foram buscados dados comparativos, entre áreas cerebrais versus raça associando tipos constitucionais versus aptidão funcional. Os fatores raças, áreas funcionais e hemisférios cerebrais podem ser variáveis dependentes entre si, pois foram encontradas diferenças estatisticamente significativas em valores correspondentes à média de densidade de neurônios das áreas estudadas nas diferentes raças, bem como entre os hemisférios cerebrais. Os resultados permitem concluir que a distribuição quantitativa de neurônios nas diferentes áreas corticais estudadas mostra diferenças significativas que estabe...

PSICOLOGIA, 2013

O estudo tem como objectivo descrever a utilização de serviços de saúde para informação, prevençã... more O estudo tem como objectivo descrever a utilização de serviços de saúde para informação, prevenção e teste do VIH por parte de homens gays em Portugal e identificar factores associados a ter efectuado o teste VIH em diferentes serviços. Para este estudo de abordagem participativa foi aplicado um inquérito por questionário a 1046 homens gays. Cerca de 27% dos participantes refere que recorreu ao CAD para obter informação sobre VIH/sida. Cerca de 83% recebeu gratuitamente preservativos no último ano. A maioria (88%) já efectuou o teste do VIH. Destes, 74% realizou­‑o no SNS, 22.5% num serviço privado e 6.5% numa ONG, verificando­‑se diferenças significativas quanto à idade, escolaridade, rendimento e nacionalidade. Os resultados indicam uma utilização dos serviços de saúde para informação, prevenção e teste do VIH pela maioria dos participantes. No entanto, é importante continuar a desenvolver esforços para promover a utilização dos serviços, em especial pelos grupos desta população q...

Journal of Dynamics and Differential Equations, 2003

A class of nonlinear parabolic partial differential equations is considered, and an exact finite ... more A class of nonlinear parabolic partial differential equations is considered, and an exact finite dimensional feedback control law is designed in order to force the systems to behave in a prescribed way. The feedback law is obtained via inertial manifold theory by reducing the system to finite dimensions. The control achieved is exact, as opposed to approximate, as obtained in

Foundations of Computational Mathematics, 1997

Abstract. Using inertial manifold theory, a finite-dimensional feedback controller is constructed... more Abstract. Using inertial manifold theory, a finite-dimensional feedback controller is constructed for a nonlinear parabolic partial differential equation so that the dynamics of the closed-loop system is close in a weighted C1-metric for the vector fields to a finite ...

Computers in Agriculture and Natural Resources, 23-25 July 2006, Orlando Florida

... João Rolim1, Pedro Godinho1, Bruno Sequeira1, Ricardo Rosa1, Paula Paredes1 and LuisSantos Pe... more ... João Rolim1, Pedro Godinho1, Bruno Sequeira1, Ricardo Rosa1, Paula Paredes1 and LuisSantos Pereira1 1 Agricultural Engineering Research Center, ISA, UTL ... Thus, three different components were built: a graphic user interface (GUI), a mathematical model and a database ...

2009 39th IEEE Frontiers in Education Conference, 2009

Abstract The premises considered by this work are that projects development in graduate courses i... more Abstract The premises considered by this work are that projects development in graduate courses is important for knowledge consolidation. However, one of the problems is that, usually, students are not prepared to manage and to be managed. This situation causes ...

Physica D: Nonlinear Phenomena, 2004

Nonlinearity, 1998

The energy equation approach used to prove the existence of the global attractor by establishing ... more The energy equation approach used to prove the existence of the global attractor by establishing the so-called asymptotic compactness property of the semigroup is considered, and a general formulation that can handle a number of weakly damped hyperbolic equations and parabolic equations on either bounded or unbounded spatial domains is presented. As examples, three specific and physically relevant problems are considered, namely the flows of a second-grade fluid, the flows of a newtonian fluid in an infinite channel past an obstacle, and a weakly damped, forced Korteweg-de Vries equation on the whole line. Contents 1. Introduction 2. Asymptotic Compactness 3. Abstract Energy Equations 4. Applications 4.1. Fluids of Second Grade 4.2. Flows Past an Obstacle 4.3. Weakly Damped, Forced Korteweg-de Vries Equation References

Nonlinear Analysis: Theory, Methods & Applications, 1998

We extend previous results on the existence of the global attractor for the 2D Navier-Stokes equa... more We extend previous results on the existence of the global attractor for the 2D Navier-Stokes equations on some unbounded domains in the sense that the forcing term need not lie in any weighted space nor is the boundary of the domain required to be smooth. The existence of the global attractor is obtained on arbitrary open sets such that the Poincaré inequality holds and for forces in the natural dual space V. The proof is based on the energy equation and the concept of asymptotic compactness. An estimate of the Hausdorff and fractal dimensions of the attractor is also given.

Journal of Esthetic and Restorative Dentistry, 2007

Background: Many post systems are available to clinicians, yet no consensus exists about which on... more Background: Many post systems are available to clinicians, yet no consensus exists about which one is better in restoring endodontically treated teeth. Purpose: This study evaluated the fracture strength of teeth with flared canals and restored with two fiber-reinforced resin systems (glass fiber: FRC Postec [Ivoclar Vivadent, Schaan, Liechtenstein]; quartz fiber: D.T. Light-Post [Bisco Dental Products, Schaumburg, IL, USA]), and one custom cast base metal (Ni-Cr) post and core system. Methods: Thirty anterior teeth had their crowns removed below the cemento-enamel junction and were endodontically treated. The canals were prepared for post fixation, and the canal walls were flared using a taper diamond bur. The prepared roots were randomly divided into three groups according to the post system. All posts were cemented with an adhesive resin cement. For the fiber-reinforced resin posts, cores were built up using microhybrid composite. Metallic crowns were luted using zinc phosphate cement. Specimens were loaded at 45 degrees in a universal testing machine at a crosshead speed of 0.5 mm/min until failure. The mode of failure was classified as repairable or nonrepairable. Results: Teeth restored with cast posts had fracture strength twice that of teeth restored with resin posts. Fiber-reinforced resin posts failed at a compressive force comparable to clinical conditions, but all failures were repairable. Conclusion: Fracture strength and mode of failure in anterior teeth with flared canals varied according to the type of post used to support a crown. CLINICAL SIGNIFICANCE Under the conditions of this study, cast posts are preferable to restore endodontically treated teeth with flared canals and no ferrule.

Journal of Dynamics and Differential Equations, 1995

In this work, we show that a strongly continuous semigroup generated by a normal operator N is co... more In this work, we show that a strongly continuous semigroup generated by a normal operator N is conjugate to the semigroup generated by the real part of N , provided zero is not an eigenvalue of the real part of N. We also show that in case N satisfies a certain sectorial property, the homeomorphism establishing the conjugacy, as well as its inverse, is locally Hölder continuous. Moreover, in case N satisfies the sectorial property and the real part of N has a pure point spectrum with an at most countable number of eigenvalues, the homeomorphism and its inverse are Lipschitz continuous.

Discrete and Continuous Dynamical Systems - Series B, 2008

We provide an analysis of the error in approximating Lyapunov exponents of dissipative PDEs on in... more We provide an analysis of the error in approximating Lyapunov exponents of dissipative PDEs on inertial manifolds using QR techniques. The reduction in the number of modes needed for an inertial form facilitates the error analysis. Numerical computations on the Kuramoto-Sivashinsky equation illustrate the results.

Discrete and Continuous Dynamical Systems, 2003

An extension to the nonautonomous case of the energy equation method for proving the existence of... more An extension to the nonautonomous case of the energy equation method for proving the existence of attractors for noncompact systems is presented. A suitable generalization of the asymptotic compactness property to the nonautonomous case, termed uniform asymptotic compactness, is given, and conditions on the energy equation associated with an abstract class of equations that assure the uniform asymptotic compactness are obtained. This general formulation is then applied to a nonautonomous Navier-Stokes system on an infinite channel past an obstacle, with time-dependent forcing and boundary conditions, and to a nonautonomous, weakly damped, forced Korteweg-de Vries equation on the real line.

Discrete and Continuous Dynamical Systems, 2003

Discrete & Continuous Dynamical Systems - A, 2010

The three-dimensional incompressible Navier-Stokes equations are considered along with its weak g... more The three-dimensional incompressible Navier-Stokes equations are considered along with its weak global attractor, which is the smallest weakly compact set which attracts all bounded sets in the weak topology of the phase space of the system (the space of square-integrable vector fields with divergence zero and appropriate periodic or no-slip boundary conditions). A number of topological properties are obtained for certain regular parts of the weak global attractor. Essentially two regular parts are considered, namely one made of points such that all weak solutions passing through it at a given initial time are strong solutions on a neighborhood of that initial time, and one made of points such that at least one weak solution passing through it at a given initial time is a strong solution on a neighborhood of that initial time. Similar topological results are obtained for the family of all trajectories in the weak global attractor.