Browsing by Issue Date, starting with "2006-08"
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- Development of indices for nonsacrificial sexing of imposex-affected Hexaplex (Trunculariopsis) Trunculus (Gastropoda : Muricidae)Publication . Vasconcelos, Paulo; Gaspar, Miguel; Castro, MargaridaThe muricid Hexaplex (Trunculariopsis) trunculus lacks external sexual dimorphism and is highly affected by imposex, which further complicates its sexual identification. In this context, the aim of this study was to develop sexual indices based on the dimensions of male and imposex-affected female penis, which could constitute a useful, simple and nonsacrificial tool for sexing live specimens of T. trunculus. The adoption of sexual indices consisting of penis dimensions of both sexes relative to individual size revealed a high accuracy in the sexual identification of sacrificed specimens (> 95% correct sexing). Additionally, multivariate discriminant analysis allowed correct sexing of 98.8% of the original 1053 sacrificed individuals, with accurate sexual identification being higher for males (99.5%) than for imposex-affected females (97.7%). An anaesthetization experiment was performed to investigate the effects produced by the anaesthetic (MgCl2) on penis measurements, to test this nonsacrificial approach and to validate the previously developed sexual indices. The anaesthetic provoked an expected enlargement in penis dimensions but, despite this side effect, the sexual indices developed for sacrificed specimens were still highly successful in sexing anaesthetized T. trunculus (generally more than 95% correct sexual identification). The practical application and some limitations of developing and employing this kind of index for the sexual identification of T. trunculus and other imposex-affected gastropod species are discussed.
- Analytical evaluation of nonlinear effects in MC-CDMA signalsPublication . Dinis, Rui; Silva, PauloThe MC-CDMA signals (multicarrier coded division multiple access) have strong envelope fluctuations which make them very prone to nonlinear effects. These effects can be both intentional (such as the ones inherent to a nonlinear signal processing for reducing the envelope fluctuations) or not (such as the ones inherent to a nonlinear power amplification). In this paper we present an analytical tool for the performance evaluation of nonlinear effects in MC-CDMA signals which takes advantage of the Gaussian-like behavior of MC-CDMA signals with a large number of subcarriers and employs results on memoryless nonlinear devices with Gaussian inputs so as to characterize statistically the signals at the output of the nonlinear device. This characterization is then used for an analytical computation of the SIR levels (signal-to-interference ratio) and the BER performance (bit error rate). A set of numerical results is presented and discussed, showing the accuracy of the analytical BER performance analysis in the presence of nonlinear effects.
- Interacção em SaúdePublication . Costa, Emília; Antequera Jurado, RosárioA investigação que se tem vindo a desenvolver nos últimos anos tem facultado preciosos contributos para o conhecimento do processo de interacção em saúde. Sabemos hoje, que a qualidade dos cuidados de saúde depende em grande medida da qualidade da interacção que se estabelece entre o profissional de saúde e os usuários dos cuidados. Sabe-se também, que a comunicação interpessoal é um instrumento fundamental para partilhar informação relevante num contexto de cuidados de saúde. Existe ainda evidência, que a comunicação efectiva entre profissionais de saúde / usuários, se encontra profundamente relacionada com aspectos tão importantes como a satisfação com os cuidados e a adesão às intervenções de saúde, sejam elas terapêuticas ou preventivas. Neste sentido, a interacção como aspecto central dos cuidados de saúde, exige uma reflexão contínua e detalhada que nos permita uma actualização constante dos conhecimentos sobre as diversas dimensões deste complexo processo.