Expressões de racismo: mudanças e continuidades

O racismo é um fenómeno bastante complexo e multifacetado, a sua compreensão exige a convocação de diversos níveis de análise, desde os processos cognitivos internos até aos factores históricos, sociais e culturais que foram moldando as formas de expressão do racismo ao longo do tempo. Neste capítulo procede-se à discussão das rupturas e continuidades nas expressões dos ‘velhos’ e ‘novos’ racismos

Optimisation of lab-scale continuous alcohol-free beer production

In order to study the formation and conversion of the most important flavour compounds, the real wort used in alcohol-free beer fermentation was mimicked by a complex model medium containing glucose, yeast extract, and selected aldehydes. The fermentation experiments were carried out in a continuously operating gas-lift reactor with brewing yeast immobilised on spent grains (brewing by-product). During the continuous experiment, parameters such as oxygen supply, residence time (Rt), and temperature (T) were varied to find the optimal conditions for the alcohol-free beer production. The formation of ethanol, higher alcohols (HA), esters (ES), as well as the reduction of aldehydes and consumption of glucose were observed. The results suggest that the process parameters represent a powerful tool in controlling the degree of fermentation and flavour formation brought about by immobilised biocatalyst. Subsequently, the optimised process parameters were used to produce real alcohol-free beer during continuous fermentation. The final product was compared with batch fermented alcohol-free beers using the methods of instrumental and sensorial analysis.Ministry of Education, Youth and Sports of the Czech Republi

El efecto de la exploración y de la indecisión vocacional en el rendimiento académico

El éxito o la falta de éste en la escuela no tiene relación directa con el rendimiento académico, sin embargo, es éste, en el ultima análisis, la manera como ésos son analizados, en grande parte de los países europeos (Eurycide, 1994). Por otra parte, es el rendimiento académico quien influye de manera determinante en el futuro académico o en la ausencia de éste, en la mayor parte de los alumnos. Dicho rendimiento se basa en las clasificaciones académicas para determinar aquellos que tendrán continuidad en el sistema educativo y aquellos que serán excluidos (Saavedra, 2001). Siguiendo esta misma línea, el objetivo del actual trabajo es analizar en qué medida la exploración y la indecisión vocacional influyen el éxito en la escuela. Se tomaron como objeto de estudio a 107 estudiantes el 4º de Eso, con una media de edad de 14,07de años (D.Pedad=0,41). Para evaluar la exploración vocacional fue utilizado el Career Exploration Survey (CES, Stumpf, Colarelli y Hartman, 1983; adap. Taveira, 1997); para evaluar la indecisión vocacional se utilizó el Career Decision Scale (CDS, Osipow, Carney, Winer, Yanico y Koshier, 1976; adap. Taveira, 1997); y para el efecto de la evaluación del rendimiento académico de los alumnos se utilizaron las calificaciones finales de los 2do y 3ero del Eso. Los resultados sugieren que el rendimiento académico puede ser afectado por el grado de activación de las dimensiones comportamentales y cognitivas de la exploración vocacional.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/18637/2004-FC

Formal requirements modeling with executable use cases and Coloured Petri Nets

This paper presents executable use cases (EUCs), which constitute a model-based approach to requirements engineering. EUCs may be used as a supplement to model-driven development (MDD) and can describe and link user-level requirements and more technical software specifications. In MDD, user-level requirements are not always explicitly described, since usually it is sufficient that one provides a specification, or platform-independent model, of the software that is to be developed. Therefore, a combination of EUCs and MDD may have potential to cover the path from user-level requirements via specifications to implementations of computer-based systems

A educação faz tudo? Crítica ao pedagogismo na "sociedade da aprendizagem"

Os discursos apologéticos acerca das todo-poderosas aprendizagem e educação ao longo da vida são reproduzidos em vários documentos de política da União Europeia e de outras agências internacionais. O seu foco é a adaptação funcional dos aprendentes individuais à empregabilidade, flexibilidade e competitividade económica, no quadro da “sociedade da aprendizagem” e da “economia do conhecimento”. Depois de analisar o racional da aprendizagem ao longo da vida, orientada para a aquisição de qualificações e habilidades, o autor conclui que os seus principais argumentos e as suas críticas contra a pedagogia moderna são frequentemente baseados em assunções pedagogistas, de carácter economicista, e em crenças exageradas no poder da educação e da aprendizagem

Global asymptotic stability for neural network models with distributed delays

In this paper, we obtain the global asymptotic stability of the zero solution of a general n-dimensional delayed differential system, by imposing a condition of dominance of the nondelayed terms which cancels the delayed effect. We consider several delayed differential systems in general settings, which allow us to study, as subclasses, the well known neural network models of Hopfield, Cohn-Grossberg, bidirectional associative memory, and static with S-type distributed delays. For these systems, we establish sufficient conditions for the existence of a unique equilibrium and its global asymptotic stability, without using the Lyapunov functional technique. Our results improve and generalize some existing ones.Fundação para a Ciência e a Tecnologia (FCT

Evolutionary approaches for strain optimization using dynamic models under a metabolic engineering perspective

One of the purposes of Systems Biology is the quantitative modeling of biochemical networks. In this effort, the use of dynamical mathematical models provides for powerful tools in the prediction of the phenotypical behavior of microorganisms under distinct environmental conditions or subject to genetic modifications. The purpose of the present study is to explore a computational environment where dynamical models are used to support simulation and optimization tasks. These will be used to study the effects of two distinct types of modifications over metabolic models: deleting a few reactions (knockouts) and changing the values of reaction kinetic parameters. In the former case, we aim to reach an optimal knockout set, under a defined objective function. In the latter, the same objective function is used, but the aim is to optimize the values of certain enzymatic kinetic coefficients. In both cases, we seek for the best model modifications that might lead to a desired impact on the concentration of chemical species in a metabolic pathway. This concept was tested by trying to maximize the production of dihydroxyacetone phosphate, using Evolutionary Computation approaches. As a case study, the central carbon metabolism of Escherichia coli is considered. A dynamical model based on ordinary differential equations is used to perform the simulations. The results validate the main features of the approach

Quantum and nanoscale modelling of exciton dynamics in polymeric systems

One of the factors that limit the efficiency of polymer-based optoelectronic devices, such as photovoltaic solar cells and light emitting diodes, is the exciton diffusion within the polymeric network. Due to the amorphous nature the of polymeric materials, the diffusion of excitons is limited by the energetic and spatial disorder in such systems, which is a consequence not only of the chemical structure of the polymer but also from its orphology at nanoscale. To get a deep understanding on how such effects influence exciton dynamics we performed a quantum molecular dynamics simulations to determine the energetic disorder within the polymer system, and Monte Carlo simulations to study exciton diffusion in three-dimensional (3D) polymer networks that present both spatial and energetic disorder at nanometre scale. Our results show clearly that exciton diffusion in poly(p-phenylenevenylene) (PPV) occurs preferentially in the direction parallel to the electrodes surface for a polymer-based optoelectronic devices with the orientation of the conjugated strands similar to those obtained by the spin-coating technique and the decay of such excitons occurs preferentially in longer strands which allow us to get insight on exciton behaviour in polymeric systems that are not possible to be obtained directly from the experiments.Fundação para a Ciência e a Tecnologia (FCT) – POCTI/CTM/41574/2001, CONC-REEQ/443/EEI/2005, SFRH/BD/22143/2005Fundação Calouste Gulbenkia

Mercado da energia eléctrica: uma modelação MPCC-NLP

O problema apresentado está relacionado com o mercado de energia eléctrica, modelado como um jogo de Stackelberg, onde a empresa líder de mercado tem o poder de manipular os preços e a capacidade de produção, de forma a maximizar o seu lucro. Devido às suas características particulares, o problema foi formulado como um Problema de Optimização com Restrições de Complementaridade (MPCC) e, posteriormente reestruturado num Problema de Programação Não Linear (NLP), com o intuito de tirar partido das suas propriedades, utilizando software específico

The influence of WebQuest learning in teaching of sexually transmitted diseases in adult education and training

The present study describes an experience that involved the development of a long lasting WebQuest in an adult education and training course, from the secondary education level, on the theme “Sexually Transmitted Diseases”. A case study was developed with the purpose of verifying if the WebQuest foments the trainees’ motivation and commitment towards learning and if it facilitates the research and interpretation of the information available online, in the production of the end result; to listen to the trainees’ opinions on the fulfilment of the WebQuest, the written assignment and the informational bulletin; to increase the trainees’ informatics skills and contribute to prepare 21st century citizens. The results of the study sustain that the WebQuest improved the constructive role of the trainees in the comprehension of the “Sexually Transmitted Diseases” theme, stimulated the acquisition of competences at the informatics level and contributed to make them become citizens that are more active and critically prepared for decision-making in the global information and knowledge society of the 21st century.CIED - Universidade do Minh