Validação da versão portuguesa da Escala de Motivação Situacional (SIMS) em contextos académicos

The Situational Motivation Scale (SIMS), seeks to evaluate the motivation experienced when carrying out a specific task. The purpose of this research was to validate a Portuguese-language version of the scale, using a sample of 409 students, by attempting to reproduce its factor structure. The reliability analysis revealed acceptable internal consistency indexes in all subscales. Construct validity was assessed through Confirmatory Factor Analysis. The contributions of the factors and index of goodness-of-fit demonstrated the need to eliminate two items, which seems to agree with the results in other validation studies. Overall, results revealed that the SIMS is composed of four consistent factors and attested its psychometric quality. The scale does seem to represent a self-report measure of situational intrinsic motivation, identified regulation, external regulation, and amotivation, and can be widely used for the assessment of this construct in Portuguese academic contexts.A Escala de Motivação Situacional (sims) procura avaliar a motivação experimentada no desempenho de uma tarefa específica. O objetivo deste estudo foi validar a versão portuguesa, com uma amostra de 409 estudantes, ao tentar reproduzir a sua estrutura fatorial. Os resultados demostram uma consistência interna adequada relativamente às subescalas. A validade de constructo foi avaliada com a Análise Fatorial Confirmatória. Os valores de contribuição de cada fator e os índices de ajustamento assinalam a necessidade de eliminação de dois itens, que, por seu turno, vai de encontro a resultados de outros estudos de validação. Em geral, os resultados indicam que a sims é composta por quatro fatores consistentes e demostram a qualidade psicométrica. A escala parece ser uma boa medida de auto-relato para avaliar a motivação intrínseca, regulação identificada, regulação externa, e amotivação situacional, podendo ser utilizada na avaliação do constructo no contexto acadêmico português. Palavras-chave: autodeterminação, motivação situacional, medidas de motivação, alunos de ensino secundário, alunos universitários.Foundation for Science and Technology (FCT), Portuga

Railway track condition assessment at network level by frequency domain analysis of GPR data

The railway track system is a crucial infrastructure for the transportation of people and goods in modern societies. With the increase in railway traffic, the availability of the track for monitoring and maintenance purposes is becoming significantly reduced. Therefore, continuous non-destructive monitoring tools for track diagnoses take on even greater importance. In this context, Ground Penetrating Radar (GPR) technique results yield valuable information on track condition, mainly in the identification of the degradation of its physical and mechanical characteristics caused by subsurface malfunctions. Nevertheless, the application of GPR to assess the ballast condition is a challenging task because the material electromagnetic properties are sensitive to both the ballast grading and water content. This work presents a novel approach, fast and practical for surveying and analysing long sections of transport infrastructure, based mainly on expedite frequency domain analysis of the GPR signal. Examples are presented with the identification of track events, ballast interventions and potential locations of malfunctions. The approach, developed to identify changes in the track infrastructure, allows for a user-friendly visualisation of the track condition, even for GPR non-professionals such as railways engineers, and may further be used to correlate with track geometric parameters. It aims to automatically detect sudden variations in the GPR signals, obtained with successive surveys over long stretches of railway lines, thus providing valuable information in asset management activities of infrastructure managers

First Steps Towards a Runtime Comparison of Natural and Artificial Evolution

Evolutionary algorithms (EAs) form a popular optimisation paradigm inspired by natural evolution. In recent years the field of evolutionary computation has developed a rigorous analytical theory to analyse their runtime on many illustrative problems. Here we apply this theory to a simple model of natural evolution. In the Strong Selection Weak Mutation (SSWM) evolutionary regime the time between occurrence of new mutations is much longer than the time it takes for a new beneficial mutation to take over the population. In this situation, the population only contains copies of one genotype and evolution can be modelled as a (1+1)-type process where the probability of accepting a new genotype (improvements or worsenings) depends on the change in fitness. We present an initial runtime analysis of SSWM, quantifying its performance for various parameters and investigating differences to the (1+1)EA. We show that SSWM can have a moderate advantage over the (1+1)EA at crossing fitness valleys and study an example where SSWM outperforms the (1+1)EA by taking advantage of information on the fitness gradient

Dynamics of transcription factor binding site evolution

Evolution of gene regulation is crucial for our understanding of the phenotypic differences between species, populations and individuals. Sequence-specific binding of transcription factors to the regulatory regions on the DNA is a key regulatory mechanism that determines gene expression and hence heritable phenotypic variation. We use a biophysical model for directional selection on gene expression to estimate the rates of gain and loss of transcription factor binding sites (TFBS) in finite populations under both point and insertion/deletion mutations. Our results show that these rates are typically slow for a single TFBS in an isolated DNA region, unless the selection is extremely strong. These rates decrease drastically with increasing TFBS length or increasingly specific protein-DNA interactions, making the evolution of sites longer than ~10 bp unlikely on typical eukaryotic speciation timescales. Similarly, evolution converges to the stationary distribution of binding sequences very slowly, making the equilibrium assumption questionable. The availability of longer regulatory sequences in which multiple binding sites can evolve simultaneously, the presence of "pre-sites" or partially decayed old sites in the initial sequence, and biophysical cooperativity between transcription factors, can all facilitate gain of TFBS and reconcile theoretical calculations with timescales inferred from comparative genetics.Comment: 28 pages, 15 figure

Relevância social da educação científica e implicações curriculares

Muitos de nós crescemos durante alguns anos quando ainda a imaginação se dirigia para o ano 2000 e o achávamos longínquo. Se não o podíamos antever, prevíamos, contudo, um tempo dominado pela ciência e pela tecnologia, muito ampliado por símbolos incontornáveis como a chegada à Lua, nos idos anos 60. Dominava, portanto, uma ideia tecnocientífica amplificadora do mundo, impondo uma mudança de rumo do tipo de conhecimento dominante, disciplinarmente espartilhado e redutor. Assente numa complexificação crescente do pensamento e do conhecimento, defende-se a ciência enquanto matéria de educação para todos os cidadãos e discute-se a relevância e implicações curriculares da educação científica na escola actual e as suas bases epistemológicas, com apoio na evolução recente, também rápida, da Filosofia da Ciência

Terceirização : o trabalho como mercadoria

Trata sobre a terceirização como um aspecto de crescente complexidade, fragmentação e redefinição do trabalho livre, tendo como principal característica a desvinculação entre as figuras do trabalhador e do empregador