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  • Author: Bruno Martins x
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Abstract

São Vicente island (República de Cabo Verde) lies within the Sahelian zone and faces a number of natural hazards, of which the most significant ones are erosion and gully formation, desertification and flash flooding hazards. Based on examples, we set out to examine the main factors involved in the development of these natural hazards from a regional point of view, while simultaneously assessing the importance of anthropic action as a structural factor. The investigation of Lazareto’s gullies (located to the west of Mindelo) aimed to determine the main factors of the gullies formation. It also sought to demonstrate that the gullies’ formation is a reliable indicator of the high rates of erosion on a regional scale. The approach to the desertification hazards was based on farmers’ perception related to the evolution of agricultural production, strategies to mitigate drought and desertification issues, consequences and future prospects based on a set of interviews conducted in Ribeira da Vinha. Finally, the intense rainfall event that occurred on August 26, 2008 was analysed to identify the main vulnerability factors of the city in light of the flash flood hazard.

Abstract

The purpose of the present study was to analyze the electromyographic (EMG) signals of the rectus femoris (RF), vastus lateralis (VL), semitendinosus (ST) and short head of the biceps femoris (BF) during the performance of stationary running at different intensities in aquatic and dry land environments. The sample consisted of 12 female volunteers who performed the stationary running exercise in aquatic and dry land environments at a submaximal cadence (80 beats·min-1 controlled by a metronome) and at maximal velocity, with EMG signal measurements from the RF, VL, ST and BF muscles. The results showed a distinct pattern between environments for each muscle examined. For the submaximal cadence of 80 beats·min-1, there was a reduced magnitude of the EMG signal in the aquatic environment, except for the ST muscle, the pattern of which was similar in both environments. In contrast to the submaximal cadence, the pattern of the EMG signal from all of the muscles showed similar magnitudes for both environments and phases of movement at maximal velocity, except for the VL muscle. Therefore, the EMG signals from the RF, VL, ST and BF muscles of women during stationary running had different patterns of activation over the range of motion between aquatic and dry land environments for different intensities. Moreover, the neuromuscular responses of the lower limbs were optimized by an increase in intensity from submaximal cadence to maximal velocity.

Abstract

Amaranth is a very important vegetable worldwide. Its leaves are consumed and the seeds are processed into various food products. Its production in the tropics is threatened by low yields which has a major impact on global production. A research aimed at improving the yield of this vegetable was carried out at lady bird organic farm Broga, 2.9450N 101.8740E, Semenyih, Selangor, Malaysia by studying the effect of genotype and organic fertilizer on the following growth indicators, red:far red ratio below canopy, stomatal conductance, leaf temperature, and dry weight. These growth indicators were monitored on a weekly basis over a period of six weeks. Three genotypes namely, Amaranthus caudatus, 3388 (green round leaf), Amaranthus caudatus, 3233 (green long leaf) and Amaranthus cruentus, 888 (red leaf) were grown on soils to which organic fertilizer was added at three different application rates (0 t/ha, 7.5 t/ha and 15 t/ha). There was no significant interaction effect of genotype and organic fertilizer on the growth indicators; however, each of these factors had significant effect on the growth of amaranth. A strong negative correlation occurred between dry weight and red:far red ratio below canopy likewise, between stomatal conductance and leaf temperature. Over a cultivation period of five weeks, the green long leaf genotype was superior showing that it is better adapted to growing in the rainforest agro ecological zone of Malaysia than the other two genotypes. Organic fertilizer application at a rate of 15 t/ha produced the lowest leaf temperature, after 4 weeks of cultivation implying better water status than 0 t/ha and 7.5 t/ha application rates. This study clearly shows that genotype and organic fertilizer have significant effect on the growth of amaranth. Therefore, these factors can be manipulated in order to enhance amaranth production.