Effects of musical cadence in the acute physiologic adaptations to head-out aquatic exercises

The purpose of this study was to analyze the relationships between musical cadence and the physiologic adaptations to basic head-out aquatic exercises. Fifteen young and clinically healthy women performed, immersed to the breast, a cardiovascular aquatic exercise called the ‘‘rocking horse.’’ The study design included an intermittent and progressive protocol starting at a 90 b min21 rhythm and increasing every 6 minutes, by 15 b min21, up to 195 b min21 or exhaustion. The rating of perceived effort (RPE) at the maximal heart rate achieved during each bout (HRmax), the percentage of the maximal theoretical heart rate estimated (%HRmax), and the blood lactate concentration ([La-]) were evaluated. The musical cadence was also calculated at 4 mmol L21 of blood lactate (R4), the RPE at R4 (RPE@R4), the HR at R4 (HR@R4), and the %HRmax at R4 (%HRmax@R4). Strong relationships were verified between the musical cadence and the RPE (R2 = 0.85; p , 0.01), the HRmax (R2 = 0.66; p , 0.01), the %HRmax (R2 = 0.61; p , 0.01), and the [La-] (R2 = 0.54; p , 0.01). The R4 was 148.13 6 17.53 b min21, the RPE@R4 was 14.53 6 2.53, the HR@R4 was 169.33 6 12.06 b min21, and the %HRmax@R4 was 85.53 6 5.72%. The main conclusion is that increasing musical cadence created an increase in the physiologic response. Therefore, instructors must choose musical cadences according to the goals of the session they are conducting to achieve the desired intensity

The relationship of anthropometrical characteristics and front crawl performance in male age-group swimmers

Swimming performance is affected by several factors including the swimming technique, the swimmer’s functional and metabolic characteristics and the level of training accomplishment. However, performance is also depending on the swimmer’s anthropometrical characteristics. The body shape, body size and body composition can play an important role to achieve higher performances

Agreement between different methods to measure the active drag coefficient in front-crawl swimming

The aim of this study was to analyze the agreement of the active drag coefficient measured through drag and propulsion methods. The sample was composed of 18 swimmers (nine boys: 15.9 ± 0.9 years; nine girls: 15.3 ± 1.2 years) recruited from a national swimming team. The velocity perturbation method was used as the drag measurement system and the Aquanex system as the propulsion system. For both sexes combined, the frontal surface area was 0.1128 ± 0.016 m2, swim velocity 1.54 ± 0.13 m∙s-1, active drag 62.81 ± 11.37 N, propulsion 68.81 ± 12.41 N. The level of the active drag coefficient agreement was calculated based on the mean values comparison, simple linear regression, and Bland Altman plots. The mean data comparison revealed non-significant differences (p > 0.05) between methods to measure the active drag coefficient. Both the linear regression (R2 = 0.82, p < 0.001) and Bland Altman plots revealed a very high agreement. The active drag coefficient should be the main outcome used in the interpretation of the swimmers’ hydrodynamic profile, because it is less sensitive to swimming velocity. Coaches and researchers should be aware that the active drag coefficient can also be calculated based on propulsion methods and not just based on drag methods. Thus, the swimming community can now use different equipment to measure the hydrodynamics of their swimmersThis work was supported by national funds (FCT - Portuguese Foundation for Science and Technology) under the project UIDB/DTP/04045/2020info:eu-repo/semantics/publishedVersio

Aerodynamic analysis of human walking, running and sprinting by numerical simulations

The drag in walking, running, and sprinting locomotion can be assessed by analytical procedures and experimental techniques. However, assessing the drag variations by these three main locomotion’s (i.e., walking, running, and sprinting) were not found using computational fluid dynamics. (CFD). Thus, the aim of this study was two-fold: (1) to assess the aerodynamics of human walking, running, and sprinting by CFD technique; 2) compare such aerodynamic characteristics between walking and running. Three 3D models were produced depicting the walking, running, and sprinting locomotion techniques, converted to computer aided design models and meshed. The drag varied with 4 locomotion type. Walking had the lowest drag, followed-up by running and then sprinting. At the same velocities, the drag was larger in walking than in running and increased with velocity. In conclusion, drag varied with locomotion type. Walking had the lowest drag, followed-up by running and then sprinting. At the same velocities, the drag was larger in walking than in running and increased with velocity.This project was founded by the Portuguese Foundation for Science and Technology, I.P. (project UIDB04045/2020)info:eu-repo/semantics/publishedVersio

Electron spin coherence in semiconductors: Considerations for a spin-based solid state quantum computer architecture

We theoretically consider coherence times for spins in two quantum computer architectures, where the qubit is the spin of an electron bound to a P donor impurity in Si or within a GaAs quantum dot. We show that low temperature decoherence is dominated by spin-spin interactions, through spectral diffusion and dipolar flip-flop mechanisms. These contributions lead to 1-100 $\mu$s calculated spin coherence times for a wide range of parameters, much higher than former estimates based on $T_{2}^{*}$ measurements.Comment: Role of the dipolar interaction clarified; Included discussion on the approximations employed in the spectral diffusion calculation. Final version to appear in Phys. Rev.

Decoherence in rf SQUID Qubits

We report measurements of coherence times of an rf SQUID qubit using pulsed microwaves and rapid flux pulses. The modified rf SQUID, described by an double-well potential, has independent, in situ, controls for the tilt and barrier height of the potential. The decay of coherent oscillations is dominated by the lifetime of the excited state and low frequency flux noise and is consistent with independent measurement of these quantities obtained by microwave spectroscopy, resonant tunneling between fluxoid wells and decay of the excited state. The oscillation's waveform is compared to analytical results obtained for finite decay rates and detuning and averaged over low frequency flux noise.Comment: 24 pages, 13 figures, submitted to the journal Quantum Information Processin

Dengue in Madeira Island

This is a preprint of a paper whose final and definite form will be published in the volume Mathematics of Planet Earth that initiates the book series CIM Series in Mathematical Sciences (CIM-MS) published by Springer. Submitted Oct/2013; Revised 16/July/2014 and 20/Sept/2014; Accepted 28/Sept/2014.Dengue is a vector-borne disease and 40% of world population is at risk. Dengue transcends international borders and can be found in tropical and subtropical regions around the world, predominantly in urban and semi-urban areas. A model for dengue disease transmission, composed by mutually-exclusive compartments representing the human and vector dynamics, is presented in this study. The data is from Madeira, a Portuguese island, where an unprecedented outbreak was detected on October 2012. The aim of this work is to simulate the repercussions of the control measures in the fight of the disease