Circulação da água na Ria de Aveiro, contribuição para o estudo da qualidade da água

O objectivo deste trabalho é estudar a circulação da água na Ria de Aveiro, contribuindo para o conhecimento da qualidade da sua água. É apresentada a caracterização morfológica e hidrológica da Ria, pondo em evidência a complexidade da sua morfologia e o carácter lagunar desta massa de água, que é justificado pelo reduzido caudal de água proveniente dos rios. O balanço do volume de água no ciclo semi-diurno de maré permitiu calcular caudais e percursos de maré. É analisada a variação de volume de ciclo quinzenal e discutida a importância das correntes residuais no transporte de substâncias na Ria. É apresentado um método de amostragem para determinar salinidades médias em segmentos dos canais da Ria, que admite condições quase estacionárias. Foram calculados os tempos de residência da água doce nos segmentos dos canais, tendo-se obtido tempos baixos próximo da barra, que aumentam para o interior dos canais. Foram realizadas observações de correntes de maré, de salinidade e de concentração de partículas em suspensão, em duas secções do canal que vai até ao Largo do Laranjo. Os resultados obtidos são compatíveis com a existência de circulação residual no ramo da Murtosa, predominando a corrente de enchente no sul e nascente, e a de vazante no norte e poente. O predomínio do gradiente longitudinal de salinidade indica também que o transporte dispersivo é importante. A concentração de partículas em suspensão está relacionada com a velocidade da corrente, indicando que a deposição e a ressuspensão alternam. O aumento da concentração média de partículas quando a salinidade diminui revela a influência do sedimento transportado pelos rios. O balanço de substâncias resultante do transporte entre os segmentos dos canais foi representado por um modelo de segmentos de prisma de maré. Os valores dos coeficientes de retorno entre os segmentos foram calibrados por um procedimento automático, baseado nas salinidades médias observadas. O modelo simula com exito a evolução do campo médio de salinidade durante períodos longos.

The Fenix II Study: A longitudinal study of psychopathology among burn patients

Psychological symptoms are common among burn survivors. However, knowledge about epidemiology and predictors of psychopathology has shown great heterogeneity in this population. The Fenix-II Project was the first epidemiological study on the psychopathological consequences of burn injuries developed in Spain, providing a detailed analysis of the progression of psychological symptoms during the first six months after injury. Three hundred and thirty-three patients were monitored and 183 were included in this study. Posttraumatic, depression and anxiety symptoms showed a general decreasing tendency across time. At 6 months, 34 patients showed clinically significant Posttraumatic Stress Disorder (PTSD) symptoms (20.5% of 166 patients reached at 6 months) as measured with the MINI Neuropsychiatric Interview. Within this group of patients, anxiety, depression and hyperarousal increased at 30 days, and avoidance 90 days after injury. The most accurate predictors of PTSD were found to be being burned in a Motor Vehicle Accident, risk of social exclusion, low body-image adjustment, anterior trunk location of the burn injury and life threat perception during the burn-shock period. Considering these factors, clinicians may identify patients at risk of PTSD development, allowing an adequate follow up and preventive interventions which may minimize the psychological consequences of burn injuries.

Fuzzy model identification by evolutionary, gradient based and memtic algorithms

One of the crucial problems of fuzzy rule modeling is how to find an optimal or at least a quasi-optimal rule base fro a certain system. In most applications there is no human expert available, or, the result of a human expert's decision is too much subjective and is not reproducible, thus some automatic method to determine the fuzzy rule base must be deployed.

Aprendizagem cooperativa em matemática: um estudo longitudinal com uma turma experimental do Novo Programa de Matemática do 2º ciclo do Ensino Básico

Tese de doutoramento, Ciências da Educação (Observação e Análise da Relação Educativa), Faculdade de Ciências Humanas e Sociais, Univ. do Algarve, 2011

Adaptabilidade de carreira e auto-eficácia na transição ao trabalho: estudo longitudinal com estudantes finalistas do ensino profissional

O impacto do contexto de trabalho no desenvolvimento vocacional tem vindo a ser estudado, há vários anos, no domínio da Psicologia Vocacional. Autores como Mark Savickas, Super e Vondraceck, reconhecem-no como um fator importante para o desenvolvimento vocacional do indivíduo, sobretudo pelos desafios que o exercício de determinada atividade profissional pode vir a colocar. Neste contexto, a experiência de estágio pode ter um efeito significativo na adaptabilidade de carreira e em outros contrutos a esta associados, sobretudo por se tratar de um contruto que traduz a competência de cada um para lidar com os desafios, obstáculos e transições inerentes à aprendizagem em contexto real de trabalho. A presente investigação, através de um estudo longitudinal com 119 alunos do ensino profissional, tem como objectivo avaliar os níveis de adaptabilidade ao longo do ano lectivo, bem como o impacto deste construto na auto-eficácia e na empregabilidade percebida, no final do ano letivo. Tem ainda como objectivo avaliar o impacto da qualidade da experiência de estágio nas diferenças eventualmente observadas nos níveis de adaptabilidade dos estudantes. Os resultados obtidos vão ao encontro da literatura, destacando a estabilidade dos níveis de adaptabilidade ao longo do ano, reforçando ainda, o papel deste construto na qualidade de preditor do sentimento de competência na transição para o mundo do trabalho. As limitações do estudo e as futuras linhas de investigação serão também apresentadas.

Design of neuro-fuzzy models by evolutionary and gradient-based algorithms

All systems found in nature exhibit, with different degrees, a nonlinear behavior. To emulate this behavior, classical systems identification techniques use, typically, linear models, for mathematical simplicity. Models inspired by biological principles (artificial neural networks) and linguistically motivated (fuzzy systems), due to their universal approximation property, are becoming alternatives to classical mathematical models. In systems identification, the design of this type of models is an iterative process, requiring, among other steps, the need to identify the model structure, as well as the estimation of the model parameters. This thesis addresses the applicability of gradient-basis algorithms for the parameter estimation phase, and the use of evolutionary algorithms for model structure selection, for the design of neuro-fuzzy systems, i.e., models that offer the transparency property found in fuzzy systems, but use, for their design, algorithms introduced in the context of neural networks. A new methodology, based on the minimization of the integral of the error, and exploiting the parameter separability property typically found in neuro-fuzzy systems, is proposed for parameter estimation. A recent evolutionary technique (bacterial algorithms), based on the natural phenomenon of microbial evolution, is combined with genetic programming, and the resulting algorithm, bacterial programming, advocated for structure determination. Different versions of this evolutionary technique are combined with gradient-based algorithms, solving problems found in fuzzy and neuro-fuzzy design, namely incorporation of a-priori knowledge, gradient algorithms initialization and model complexity reduction.

Sustained drug use changes following hepatitis C screening and counseling among recently infected persons who inject drugs: a longitudinal study

BACKGROUND: Notification of hepatitis C virus (HCV) positive status is known to have short-term impacts on subsequent alcohol, drug use and injection behaviors among persons who inject drugs (PWID). It remains to be established whether post-screening behavioral changes extend over time for PWID and whether screening test notification has behavioral impacts among HCV-negative PWID. This study sought to longitudinally assess substance use and injection behaviors after HCV status notification among HCV seroconverters and HCV-negative PWID. METHODS: Initially HCV-seronegative PWID (n = 208) were followed prospectively between 2004 and 2011 in Montreal, Canada. Semi-annual screening visits included blood sampling and an interview-administered questionnaire assessing substance use and injection behaviors. Multivariable generalized estimating equation analyses were conducted to assess substance use and behavior changes over time and compare changes between HCV seroconverters and HCV-seronegative participants while adjusting for baseline characteristics. RESULTS: Of the 208 participants (83% male; mean age, 34.7 years, mean follow-up time, 39 months), 69 (33.2%) seroconverted to HCV. A linear decrease in syringe sharing behavior was observed over time after HCV and status notification, whereas a 10% decrease for each additional 3 months of follow-up was observed for injection cocaine and heroin use among HCV seroconverters but not among HCV-seronegative PWID (P < .05). No significant changes were observed in alcohol use. CONCLUSIONS: Our results indicate that notification of HCV-positive status is associated with reduced injection drug use among seroconverters. Among PWID deemed seronegative after screening, there is no sustained trend for change in risk behavior.

Tecnologias ubíquas nas aulas de ciências naturais : da surpresa à valorização e utilização plena : um estudo longitudinal

Tese de doutoramento, Educação (Didática das Ciências), Universidade de Lisboa, Instituto de Educação, 2014

Um estudo longitudinal sobre o efeito da formação no índice de autoeficácia e nos níveis de utilização das TIC dos professores

Tese de doutoramento, Educação (Tecnologias de Informação e Comunicação na Educação), Universidade de Lisboa, Instituto de Educação, 2015

Biology and ecology of the white prawn Palaemon longirostris H. Milne Edwards, 1837 (Crustacea, Decapoda, Palaemonidae) in the Mira River, Portugal

Tese de doutoramento, Biologia (Ecografia), Universidade de Lisboa, Faculdade de Ciências, 2014

Exploring Variations in Teachers' Work, Lives and Their Effects on Pupils: Key Findings and Implications from a Longitudinal Mixed Methods Study

This article outlines the research design of a large‐scale, longitudinal research study in England intended to describe and explore variations in teachers' work, lives and their effects on pupils' educational outcomes. The study, funded by the Department for Education and Skills (DfES) and incorporated into the Teaching and Learning Research Programme (TLRP) as an ‘Associate Project’, used an innovative mixed‐methods research design to create case studies of 300 teachers in Years 2, 6 and 9. The research was conducted over three consecutive academic years and collected a wide range of data through interviews, questionnaire surveys of teachers' and pupils' views and assessment data on pupils' attainments in English and mathematics. The text summarises the main findings from the research in relation to four interconnected themes of the study: Professional Life Phases; Professional Identity; Relative Effectiveness; and Resilience and Commitment. The influence of school context, in terms of level of social disadvantage of pupil intake, is also investigated. Key findings and their implications for policy and practice are highlighted.

Four years on: a longitudinal study assessing the impact of a virtual community of practice

This paper explores the long term impact of a virtual learning community (VLC) from the perspective of community members and their employing organization. It argues that membership potentially has a significant impact on individual identities and careers, and that managed communities provide an important means for strategic workforce development. The study evaluates the impact of membership of a VLC over a four year period within the context of the theoretical frameworks of communities of practice and identity theory. The concept of boundary crossing is also explored in relation to VLCs. The paper considers the benefits to host organisations in supporting structured VLCs as a means of enabling workforce development and supporting change and innovation.

Places and preferences: a longitudinal analysis of self-selection and contextual effects

Contextual theories of political behaviour assert that the contexts in which people live influence their political beliefs and vote choices. Most studies of political assimilation, however, rely on cross-sectional data and fail to distinguish contextual influence from self-selection of individuals into areas. This paper advances understanding of this longstanding controversy by tracking thousands of individuals over an 18-year period in England. We observe individual-level left-right position and party identification before and after residential moves across areas with different political orientations. We find evidence of both non-random selection into areas and assimilation of new entrants to the majority political orientation. However, these effects are contingent on the type of area an individual moves to and, moreover, contextual effects are weak and dominated by the larger effect of self-selection into areas.

Introduction to the Special Section Value Development from Middle Childhood to Early Adulthood: New Insights from Longitudinal and Genetically Informed Research

Research into values at an early age has only started recently, although it has expanded quickly and dynamically in the past years. The purpose of this article is twofold: First, it provides an introduction to a special section that aims to help fill the gap in value development research. The special section brings together four new longitudinal and genetically informed studies of value development from the beginning of middle childhood through early adulthood. Second, this article reviews recent research from this special section and beyond, aiming to provide new directions to the field. With new methods for assessing children's values and an increased awareness of the role of values in children's and adolescents' development, the field now seems ripe for an in-depth investigation. Our review of empirical evidence shows that, as is the case with adults, children's values are organized based on compatibilities and conflicts in their underlying motivations. Values show some consistency across situations, as well as stability across time. This longitudinal stability tends to increase with age, although mean changes are also observed. These patterns of change seem to be compatible with Schwartz's (1992) theory of values (e.g., if the importance of openness to change values increases, the importance of conservation values decreases). The contributions of culture, family, peers, significant life events, and individual characteristics to values are discussed, as well as the development of values as guides for behavior.

Reciprocal relations across time between basic values and value-expressive behaviors: A longitudinal study among children

Tracing children’s values and value-expressive behavior over a sixth-month period, we examined stability and change of values and behavior and the reciprocal relations between them. Three hundred and ten sixth-grade students in Italy completed value and value-expressive behavior questionnaires three times in three-month intervals during the scholastic year. We assessed Schwartz's (1992) higher-order values of conservation, openness to change, self-enhancement, and self-transcendence, as well as their respective expressive behaviors. Reciprocal relations over time between values and behaviors were examined using a cross-lagged longitudinal design. Results showed that values and behaviors had reciprocal longitudinal effects on one another, after the stability of the variables was taken into account (i.e., values predicted change in behaviors, but also behaviors predicted change in values). Our findings also revealed that: (1) values were more stable over time than behaviors, and (2) the longitudinal effect of values on behaviors tended to be stronger than the longitudinal effect of behaviors on values. Findings are discussed in light of the recent developmental literature on value change.