Evaluation of the respiratory motion effect in small animal PET images with GATE Monte Carlo simulations

The rapid growth in genetics and molecular biology combined with the development of techniques for genetically engineering small animals has led to increased interest in in vivo small animal imaging. Small animal imaging has been applied frequently to the imaging of small animals (mice and rats), which are ubiquitous in modeling human diseases and testing treatments. The use of PET in small animals allows the use of subjects as their own control, reducing the interanimal variability. This allows performing longitudinal studies on the same animal and improves the accuracy of biological models. However, small animal PET still suffers from several limitations. The amounts of radiotracers needed, limited scanner sensitivity, image resolution and image quantification issues, all could clearly benefit from additional research. Because nuclear medicine imaging deals with radioactive decay, the emission of radiation energy through photons and particles alongside with the detection of these quanta and particles in different materials make Monte Carlo method an important simulation tool in both nuclear medicine research and clinical practice. In order to optimize the quantitative use of PET in clinical practice, data- and image-processing methods are also a field of intense interest and development. The evaluation of such methods often relies on the use of simulated data and images since these offer control of the ground truth. Monte Carlo simulations are widely used for PET simulation since they take into account all the random processes involved in PET imaging, from the emission of the positron to the detection of the photons by the detectors. Simulation techniques have become an importance and indispensable complement to a wide range of problems that could not be addressed by experimental or analytical approaches.

Escrever com arte

O presente estudo pretende promover a articulação entre as áreas curriculares de Língua Portuguesa e Expressão Plástica, através da construção de um projeto de intervenção que foi implementado numa turma de 2.º ano do 1.º Ciclo do Ensino Básico. Com este projeto pretendeu-se criar um ambiente motivador para a aprendizagem da produção escrita, mais concretamente do texto descritivo, através de conhecimento e exploração de obras de arte e pintores de referência. No início do projeto analisaram-se as produções escritas dos alunos, de forma identificar o nível de desempenho na produção de texto descritivo. Numa segunda etapa, foi implementado o projeto de intervenção, organizado em torno de sequências didáticas. Essas sequências visavam um contacto mais próximo com diversas obras de arte, biografias de pintores e espaços culturais, proporcionando aos alunos o desenvolvimento da capacidade de contemplar e de descrever uma obra de arte e de verbalizar emoções e impressões acerca das obras contempladas. Por outro lado, pretendeu-se também desenvolver no aluno a capacidade de analisar uma obra tendo em conta os elementos técnicos nela contidos e de formular um juízo crítico e justificá-lo. No final do processo, foram novamente produzidos textos descritivos, a partir do mesmo estímulo, de forma a avaliar os ganhos do trabalho desenvolvido. No final da implementação deste projeto, foi possível perceber que o trabalho desenvolvido contribuiu para o desenvolvimento da competência de escrita dos alunos, nomeadamente do texto descritivo. Concluiu-se ainda, pela análise dos dados recolhidos, que a articulação destas duas áreas constituiu um fator de motivação e de aprendizagem para estes alunos.

Neonatal anthropometry: a tool to evaluate the nutritional status and predict early and late risks

Neonatal anthropometry is an inexpensive, noninvasive and convenient tool for bedside evaluation, especially in sick and fragile neonates. Anthropometry can be used in neonates as a tool for several purposes: diagnosis of foetal malnutrition and prediction of early postnatal complications; postnatal assessment of growth, body composition and nutritional status; prediction of long-term complications including metabolic syndrome; assessment of dysmorphology; and estimation of body surface. However, in this age group anthropometry has been notorious for its inaccuracy and the main concern is to make validated indices available. Direct measurements, such as body weight, length and body circumferences are the most commonly used measurements for nutritional assessment in clinical practice and in field studies. Body weight is the most reliable anthropometric measurement and therefore is often used alone in the assessment of the nutritional status, despite not reflecting body composition. Derived indices from direct measurements have been proposed to improve the accuracy of anthropometry. Equations based on body weight and length, mid-arm circumference/head circumference ratio, and upper-arm cross-sectional areas are among the most used derived indices to assess nutritional status and body proportionality, even though these indices require further validation for the estimation of body composition in neonates.