Browsing by Author "Pimenta, Rui"
Now showing 1 - 10 of 39
Results Per Page
Sort Options
- Affinity coefficient for clustering autoregressive moving average modelsPublication . Nascimento, Ana Paula; Oliveira, Alexandra; Faria, Brígida Mónica; Pimenta, Rui; Vieira, Mónica; Prudêncio, Cristina; Nicolau, Helena BacelarIn various fields, such as economics, finance, bioinformatics, geology, and medicine, namely, in the cases of electroencephalogram, electrocardiogram, and biotechnology, cluster analysis of time series is necessary. The first step in cluster applications is to establish a similarity/dissimilarity coefficient between time series. This article introduces an extension of the affinity coefficient for the autoregressive expansions of the invertible autoregressive moving average models to measure their similarity between them. An application of the affinity coefficient between time series was developed and implemented in R. Cluster analysis is performed with the corresponding distance for the estimated simulated autoregressive moving average of order one. The primary findings indicate that processes with similar forecast functions are grouped (in the same cluster) as expected concerning the affinity coefficient. It was also possible to conclude that this affinity coefficient is very sensitive to the behavior changes of the forecast functions: processes with small different forecast functions appear to be well separated in different clusters. Moreover, if the two processes have at least an infinite number of π- weights with a symmetric signal, the affinity value is also symmetric.
- Análise fatorial de doenças não transmissíveis em função das taxas de mortalidade ao longo do tempoPublication . Nascimento, Ana Paula; Prudêncio, Cristina; Vieira, Mónica; Faria, Brígida Mónica; Pimenta, Rui; Bacelar-Nicolau, HelenaA Saúde Pública visaestudar, prevenir doenças, prolongar a vida e melhorar a qualidade de vida por meio de esforços organizados e escolhas informadas. Assim, é necessárioconhecer e analisar os fatores de saúde de uma população. A Análise de Dados Multivariada difere da Análise Estatística Multivariada clássica (confirmatória), pois nesta última o papel central está no modelo e nas inferências estatísticas, enquanto que na análise de dados multivariada são os dados que assumem o papel primordial. Atécnica de análise fatorial pode ajudar na procura de causas comuns ou fatores de risco para melhorar a medicina preventiva. Pretende-se, com o presente estudo, encontrar fatores de doenças não transmissíveis eventualmente sugestivos de um comportamento comum das mesmas, utilizando análise fatorial. Para encontrar fatores que expliquem as associações entre doenças não transmissíveis, foi aplicada a análise fatorial separadamente para o sexo masculino e feminino, e considerando como variáveis as taxas de mortalidade padronizadas ao longo do tempo de cada uma das doenças. Foram identificados três fatores de doenças não transmissíveis, no sexo feminino, explicando 80,36% da variância e quatro fatores de doenças não transmissíveis,no sexo masculino, explicando 77,22% da variância. Em ambos os sexos as doenças cerebrovasculares e a cardiopatia isquémica contribuem positivamente para o primeiro fator, o que é comum ser encontrado na literatura no caso do sexo masculino, aplicando métodos de cluster analysis. A análise fatorial juntamente com outras metodologias de análise de dados multivariados, pode ajudar na identificação de causas comuns ou fatores de risco para melhorar a medicina preventiva. O estudo dos fatores de risco e/ou mecanismos fisiopatológicos comuns que de uma forma direta ou indireta, possam potenciar o desenvolvimento comum das patologias encontradas nos grupos/fatores é prioritário dada a relevância das doenças não transmissíveis.
- Assessing diabetes health literacy, knowledge and empowerment in northern PortugalPublication . Morais, Carminda S.; Pimenta, Rui; Ferreira, Pedro Lopes; Boavida, José M.; Amorim, José P.We evaluated the disease management, knowledge and quality of life (QoL) of people with type 2 diabetes, followed in the ambulatory of a Hospital in the North of Portugal. A questionnaire of socio-demographic and clinical characterization, and Portuguese versions of the DES-SF, DKT and EQ-5D were administered to a random sample of 260 individuals. The results showed that people in general feel able of self-management, with a mean±SD score of 3.7±0.7. DKT registered 63.4±12.3% of correct answers among diabetes non-insulin-treated individuals and 65.7±12.4% among the insulin-treated (p<0.001). The QoL, evaluated through EQ-5D index, presented a mean value of 0.65±0.3. We evidenced a significant positive correlation between the ability to control, the knowledge and the QoL. The conclusions obtained may help promote QoL and literacy enhancement, as well as the empowerment of individuals with type 2 diabetes.
- Assessing statistical reasoning through project workPublication . Pimenta, RuiNew technologies involve a reformulation of contents and methodology used for teaching statistics. Developing students’ statistical reasoning becomes an important task for teachers of applied statistics. This is particularly true in the field of health sciences. In this work the statistical reasoning ability acquired by health sciences students was evaluated in the context of their final undergraduate project.
- Atitudes face à estatística em diferentes grupos de profissionais de saúde em formaçãoPublication . Pimenta, Rui; Pereira, Ilídio; Costa, Elísio; Vieira, MargaridaUma grande parte das decisões que os profissionais de saúde tomam no seu dia-a-dia tem suporte estatístico num modelo que integre a prática clínica baseada na evidência. A atitude que estes profissionais têm face à estatística pode condicionar o exercício da competência estatística na sua prática clínica e o correcto desenvolvimento da intuição estatística. Neste trabalho, analisámos as diferentes componentes das atitudes face à estatística de estudantes e profissionais em formação, em distintas áreas de formação clínica e em distintos ciclos formativos, através das suas respostas ao Inquérito Atitudes Face à Estatística (SATS 28). Pretendemos, em primeiro lugar, avaliar a e analisar a relação entre as componentes das atitudes na nossa amostra. De seguida, recorremos a técnicas de visualização radial para verificar que componentes das atitudes permitem explicar melhor a variação das respostas dos estudantes. Por último, pretendemos comparar as atitudes face à estatística em diferentes grupos de profissionais em formação tomando em linha de conta a sua situação face à graduação. Recorremos a uma análise de variância a dois factores para estudar a interacção entre os factores área de formação e situação face à graduação e comparar os resultados obtidos nos diferentes grupos que decorrem desta análise. Os nossos resultados mostram que os estudantes das ciências da saúde têm, geralmente, uma atitude positiva face à estatística embora a dificuldade percebida seja mais relevante do que em estudos realizados anteriormente noutras áreas de formação.
- Building instrument to assess user satisfaction in communicating with health professionals based on the consensus of the Delphi methodPublication . Santos, A. H.; Pimenta, Rui; Santos, Paula Clara; Moreira, PauloRecent research in user-health professionals communication have emphasized the need to develop new instruments to evaluate user satisfaction in communicating with health professionals
- Cluster analysis of noncommunicable diseases in PortugalPublication . Nascimento, Ana Paula; Prudêncio, Cristina; Vieira, Mónica; Pimenta, Rui; Bacelar-Nicolau, HelenaThe most common noncommunicable diseases, such as cardiovascular diseases, cancer or respiratory diseases, are a problem in global and national growth. The World Health Organization (WHO) considers it a priority to study the specific causes of these diseases for trend monitoring. The aim is to identify a hierarchy of clusters of Portuguese mortality by noncommunicable diseases using the ascending hierarchical classification methodology. The results identifying three clusters A, A2 and B2 of diseases are proposed for study. It is suggested that the risk factors and / or pathophysiological mechanisms that in a direct or indirect way may enhance the common development of the pathologies found in the clusters studied should be an object of priority study.
- Comparison of attitudes towards statistics in graduate and undergraduate health sciences' studentsPublication . Pimenta, Rui; Faria, Brigida Mónica; Pereira, Ilídio; Costa, Elísio; Vieira, MargaridaThe ultimate goal of statistical education is to provide an appropriate use of statistical thinking (Schau et al., 1995). This is particularly pertinent in the context of the health sciences since these professionals need to carry out their own investigations and make decisions under uncertainty integrating the best practices of evidence based medicine. Health professionals develop, at times, anxiety towards statistics due to their fear of mathematics. However, biostatistics courses can, nowadays, be conducted without a high level of calculus. Students’ attitudes might influence their learning of statistical concepts as much as their cognitive abilities. The influence of attitudes towards statistics on the development of statistical reasoning and thinking has been studied in different ways (Carmona, 2004; Blanco, 2008). However, the attitudes towards statistics in health sciences’ students are a new kind of research particularly pertinent due to an increasing number of students in this field. The difficulties in the use of statistics by different groups of professionals, particularly by health professionals, are well documented mainly when carrying out research. Health professionals need to promote their statistical abilities in order to be able to recognize when additional knowledge and skills are required, to obtain this additional statistical understanding or, better yet, to claim the consultation of a statistician. Improvement of positive attitudes towards statistics is a critical goal in statistics education. Positive attitudes contribute to a better use of statistical knowledge and to a better understanding of the variation inherent to data, enabling better decision-making under uncertainty when dealing with statistics. In this work, we evaluate, compare and present the first study which analyses the attitudes towards statistics in Portuguese health sciences students enrolling in postgraduate or undergraduate programs.
- Comparison of methodologies of CSR index: application to the PSI 20 companiesPublication . Fernandes, Paula; Monte, Ana Paula; Pimenta, Rui; Afonso, SandraCorporate Social Responsibility (CSR) has assumed increasing importance over the past several decades, globally resulting from companies’ response to the demands of markets and society for responsible growth, both social and environmentally. At a European level, the CSR was initially boosted in 1993 by the former President of the European Commission, Jacques Delors, who called for more socially responsible action from companies, and culminated in 2001 with the publication of the Green Paper on CSR, by the European Commission in which the areas and guidelines for desirable social responsibility practices were defined. The measurement of social or CSR performance has not been consensual, which accounts for the existence of several methods. These use a variety of criteria ranging from expert evaluation to the analysis of reports and other documents or considerations of performance measures of pollution control. Each of these criteria is not exempt from criticism and limitations, as they are one-dimensional or do not reflect all aspects of CSR. Based on these measures, some evaluation CSR indices were developed, having been used in decision-making and positioning of the companies in their social and environmental performance. The most commonly used indices are those provided by the rating agency Kinder, Lindenberg and Domini index or reputation index of Fortune. This paper aims to compare the application of two methods in defining the levels of CSR from a CSR index, constructed for 19 of the 20 companies comprising the PSI-20, the Portuguese stock market index, the Euronext Lisbon. One of the methodologies defines five intervals of CSR using the cut-point method; the other considers a scale of 5 points (5 grades) with constant intervals. In order to construct the index, 247 items were considered, comprising the different dimensions of social responsibility suggested by the European Commission Green Paper on CRS of 2001 and the guidelines of the Global Reporting Initiative. We analyzed the contents of sustainability reports and financial reports of companies under research in order to assign a score (which will be 0 if the item is not observed, 0.5 if is only partially observed or 1 whether it is observed) for measurement of each item of responsibility, since there are no quantifiable and objective social responsibility indicators. The CSR index of a company, at any given time, is the sum of the scores across all 247 items. The categorization of companies in the CSR levels depends on the referred methodology to the definition of intervals. In brief, by using the two approaches, we found that the Portuguese companies which were analyzed denote a growing sensitivity in the adhesion and dissemination of their social responsibility practices, investing in a more specific and detailed disclosure and, in particular, complying with the guidelines of the Global Reporting Initiative.
- Conhecimentos e opiniões de médicos e farmacêuticos acerca dos genéricos versus padrões de prescrição/dispensaPublication . Pimenta, Rui; Rodrigues, Carla P.; Fernandes, Paula O.Na actual situação da economia portuguesa, a política do medicamento assume uma importância primordial na prossecução de uma redução da despesa pública com medicamentos para 1,25% do PIB até final de 2012 e para cerca de 1% do PIB em 2013, conforme o acordo estabelecido com as entidades internacionais. No entanto, do ponto de vista do cidadão, a despesa privada em medicamentos é também uma temática na ordem do dia. Poucos temas são tão controversos na área da política do medicamento como a introdução de genéricos no mercado de medicamentos, contudo, estes podem desempenhar um papel fundamental na optimização da afectação de recursos. São muitas as questões levantadas contra e a favor da qualidade, segurança e eficácia dos genéricos. Se os médicos, através da prescrição, são o factor decisivo para o aumento da quota de genéricos; os farmacêuticos enquanto dispensadores assumem um papel preponderante na sensibilização dos utentes para a sua aceitação e adesão à terapêutica.