Nuno F. Loureiro

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BACKGROUND This study examines associations between perceptions of neighbourhood environment and physical activity and sports within Portuguese adolescents. METHODS The sample consisted of 4,877 individuals of both genders, with an average age of 14 years. The instrument used was the Health Behavior School-aged Children questionnaire. RESULTS(More)
Two-dimensional numerical simulations of the effect of background turbulence on 2D resistive magnetic reconnection are presented. For sufficiently small values of the re-sistivity (η) and moderate values of the turbulent power (), the reconnection rate is found to have a much weaker dependence on η than the Sweet-Parker scaling of η 1/2 and is even(More)
An efficient, iterative semi-implicit (SI) numerical method for the time integration of stiff wave systems is presented. Physics-based assumptions are used to derive a convergent iterative formulation of the SI scheme which enables the monitoring and control of the error introduced by the SI operator. This iteration essentially turns a semi-implicit method(More)
The recent realization that Sweet-Parker current sheets are violently unstable to the secondary tearing (plasmoid) instability implies that such current sheets cannot occur in real systems. This suggests that, in order to understand the onset of magnetic reconnection, one needs to consider the growth of the tearing instability in a current layer as it is(More)
We explored the effect of gravity on the perceived representation of the absolute distance of objects to the observers within the range from 1.5-6 m. Experiments were performed on board the CNES Airbus Zero-G during parabolic flights eliciting repeated exposures to short periods of microgravity (0 g), hypergravity (1.8 g), and normal gravity (1 g). Two(More)
Landau damping (phase mixing) is perhaps the most salient feature of weakly collisional plasmas. Phase mixing plays a crucial role in kinetic plasma turbulence— it transfers energy to small velocity space scales, and provides a route to dissipation to the turbulent cascade. Phase mixing has been well understood in the linear limit for nearly seventy years,(More)
Introduction: The pattern of sleep plays an important role in protecting the adolescents' health. The main objective of this research is to determine the relationship between sufficient sleep (≥ 8 hours of sleep per night on school days) and health-risk behaviours in Portuguese adolescents. Methods: 5,050 participants with an average age of 13.98 (DP ±(More)
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