Uma perspectiva computacional sobre catálise enzimática

Enzymes are extremely efficient catalysts. Here, part of the mechanisms proposed to explain this catalytic power will be compared to quantitative experimental results and computer simulations. Influence of the enzymatic environment over species along the reaction coordinate will be analysed. Concepts of transition state stabilisation and reactant destabilisation will be confronted. Divided site model and near-attack conformation hypotheses will also be discussed. Molecular interactions such as covalent catalysis, general acid-base catalysis, electrostatics, entropic effects, steric hindrance, quantum and dynamical effects will also be analysed as sources of catalysis. Reaction mechanisms, in particular that catalysed by protein tyrosine phosphatases, illustrate the concepts.

Propriedades dinâmicas de fluidos por simulação computacional: métodos híbridos atomístico-contínuo

Computational methods for the calculation of dynamical properties of fluids might consider the system as a continuum or as an assembly of molecules. Molecular dynamics (MD) simulation includes molecular resolution, whereas computational fluid dynamics (CFD) considers the fluid as a continuum. This work provides a review of hybrid methods MD/CFD recently proposed in the literature. Theoretical foundations, basic approaches of computational methods, and dynamical properties typically calculated by MD and CFD are first presented in order to appreciate the similarities and differences between these two methods. Then, methods for coupling MD and CFD, and applications of hybrid simulations MD/CFD, are presented.

Using sentinels to detect intersections of convex and nonconvex polygons

We describe finite sets of points, called sentinels, which allow us to decide if isometric copies of polygons, convex or not, intersect. As an example of the applicability of the concept of sentinel, we explain how they can be used to formulate an algorithm based on the optimization of differentiable models to pack polygons in convex sets. Mathematical subject classification: 90C53, 65K05.

Psicologia, diretrizes curriculares e processos educativos na Amazônia: um estudo da formação de psicólogos

Este estudo objetiva analisar a formação de psicólogos frente às Diretrizes Curriculares Nacionais para os Cursos de Psicologia no que tange aos processos educativos. Realizamos revisão da literatura pertinente ao tema, pesquisa documental e empírica com alunos, professores e coordenador de curso, utilizando questionário, entrevistas e adotando a estratégia de triangulação a partir das categorias: perfil sociocultural; nível de conhecimento acerca das mudanças oriundas das Diretrizes para o curso de Psicologia; percepção na qualidade da prática docente; nível de satisfação com relação à própria formação universitária, tomando como referência os conhecimentos, habilidades e competências adquiridas. Apresenta contribuições para a compreensão da formação de psicólogos no campo da educação na Amazônia no Ensino Superior, centrada na construção de um profissional de pensamento e prática críticos, capaz de analisar as transformações nos vários contextos educacionais e escolares, utilizando referenciais que permitam a compreensão do fenômeno educativo na sua complexidade.

The single machine earliness and tardiness scheduling problem: lower bounds and a branch-and-bound algorithm

This paper addresses the single machine scheduling problem with a common due date aiming to minimize earliness and tardiness penalties. Due to its complexity, most of the previous studies in the literature deal with this problem using heuristics and metaheuristics approaches. With the intention of contributing to the study of this problem, a branch-and-bound algorithm is proposed. Lower bounds and pruning rules that exploit properties of the problem are introduced. The proposed approach is examined through a computational comparative study with 280 problems involving different due date scenarios. In addition, the values of optimal solutions for small problems from a known benchmark are provided.