Effects of static stretching following a dynamic warm-up on speed, agility and power

Static stretching prior to sport has been shown to decrease force production in comparison to the increasing popularity of dynamic warm-up methods. However some athletes continue to use a bout of static stretching following dynamic methods. The purpose of this study was to investigate the effects on speed, agility and power following a period of additional static stretching following a dynamic warm-up routine. Twenty-five male University students who participated in team sports performed two warm-up protocols concentrating on the lower body one week apart through a randomised cross over design. The dynamic warm-up (DW) protocol used a series of specific progressive exercises lasting 10 minutes over a distance of 20m. The dynamic warm-up plus static stretching (DWS) protocol used the same DW protocol followed by a 5 minute period during which 7 muscle groups were stretched. Following each warm-up the subjects performed a countermovement vertical jump, 20m sprint and Illinois agility test, 1 minute apart. The results demonstrated no significant differences in speed, agility and jump performance following the two protocols DW and DWS. The study concludes that performing static stretching following a dynamic warm-up prior to performance does not significantly affect speed, agility and vertical jump performance.

Sampling scarab beetles in tropical forests: the effect of light source and night sampling periods

Light traps have been used widely to sample insect abundance and diversity, but their performance for sampling scarab beetles in tropical forests based on light source type and sampling hours throughout the night has not been evaluated. The efficiency of mercury-vapour lamps, cool white light and ultraviolet light sources in attracting Dynastinae, Melolonthinae and Rutelinae scarab beetles, and the most adequate period of the night to carry out the sampling was tested in different forest areas of Costa Rica. Our results showed that light source wavelengths and hours of sampling influenced scarab beetle catches. No significant differences were observed in trap performance between the ultraviolet light and mercury-vapour traps, whereas these two methods caught significantly more species richness and abundance than cool white light traps. Species composition also varied between methods. Large differences appear between catches in the sampling period, with the first five hours of the night being more effective than the last five hours. Because of their high efficiency and logistic advantages, we recommend ultraviolet light traps deployed during the first hours of the night as the best sampling method for biodiversity studies of those scarab beetles in tropical forests.

A Survey on FPGA-Based Sensor Systems: Towards Intelligent and Reconfigurable Low-Power Sensors for Computer Vision, Control and Signal Processing

The current trend in the evolution of sensor systems seeks ways to provide more accuracy and resolution, while at the same time decreasing the size and power consumption. The use of Field Programmable Gate Arrays (FPGAs) provides specific reprogrammable hardware technology that can be properly exploited to obtain a reconfigurable sensor system. This adaptation capability enables the implementation of complex applications using the partial reconfigurability at a very low-power consumption. For highly demanding tasks FPGAs have been favored due to the high efficiency provided by their architectural flexibility (parallelism, on-chip memory, etc.), reconfigurability and superb performance in the development of algorithms. FPGAs have improved the performance of sensor systems and have triggered a clear increase in their use in new fields of application. A new generation of smarter, reconfigurable and lower power consumption sensors is being developed in Spain based on FPGAs. In this paper, a review of these developments is presented, describing as well the FPGA technologies employed by the different research groups and providing an overview of future research within this field.

Measuring the effective focal length and shape factor of a thick lens using a microscope

The optical power of a thick spherical lens and its Coddington shape factor are essential magnitudes that characterize its image quality. Here, we propose an experimental procedure and apparatus that allow accurate determination of those magnitudes for any spherical lens from geometrical measurements. The performance of the technique and the used instruments are simple since it only requires a microscope and an optical mouse. The propose overcomes the drawbacks of other devices that need of the refractive index or may damage the lens surfaces, like spherometers, and provides similar results to those from commercial lensmeters.