Anaerobic energy provision does not limit Wingate exercise performance in endurance-trained cyclists

[EN] The aim of this study was to evaluate the effects of severe acute hypoxia on exercise performance and metabolism during 30-s Wingate tests. Five endurance- (E) and five sprint- (S) trained track cyclists from the Spanish National Team performed 30-s Wingate tests in normoxia and hypoxia (inspired O(2) fraction = 0.10). Oxygen deficit was estimated from submaximal cycling economy tests by use of a nonlinear model. E cyclists showed higher maximal O(2) uptake than S (72 +/- 1 and 62 +/- 2 ml x kg(-1) x min(-1), P < 0.05). S cyclists achieved higher peak and mean power output, and 33% larger oxygen deficit than E (P < 0.05). During the Wingate test in normoxia, S relied more on anaerobic energy sources than E (P < 0.05); however, S showed a larger fatigue index in both conditions (P < 0.05). Compared with normoxia, hypoxia lowered O(2) uptake by 16% in E and S (P < 0.05). Peak power output, fatigue index, and exercise femoral vein blood lactate concentration were not altered by hypoxia in any group. Endurance cyclists, unlike S, maintained their mean power output in hypoxia by increasing their anaerobic energy production, as shown by 7% greater oxygen deficit and 11% higher postexercise lactate concentration. In conclusion, performance during 30-s Wingate tests in severe acute hypoxia is maintained or barely reduced owing to the enhancement of the anaerobic energy release. The effect of severe acute hypoxia on supramaximal exercise performance depends on training background.

Phenolic Constituents, Antioxidant and Preliminary Antimycoplasmic Activities of Leaf Skin and Flowers of Aloe vera (L.) Burm. f. (syn. A. barbadensis Mill.) from the Canary Islands (Spain)

[EN]The methanol extracts of leaf skins and flowers of Aloe vera from the Canary Islands were analyzed for their phenolic profiles and screened for their antioxidant and antimycoplasmic activities. The use of reversed phase high performance liquid chromatography (RP-HPLC) allowed the identification of 18 phenolic constituents. Leaf skin extracts were characterized by the abundance of catechin, sinapic acid and quercitrin. Gentisic acid, epicatechin and quercitrin were the most prominent phenolic compounds of the flowers. The in vitro antioxidant activities determined by using the 1,1-diphenyl-2- picrylhydrazyl (DPPH) and ferric antioxidant reducing power (FRAP) assays revealed that both extracts exhibited antioxidant activity, being the leaf skin extract the most active fraction. The leaf skin extract was also found to be active against the microbial strains tested. Therefore, A. vera extracts from leaf skin and flowers can be considered as good natural antioxidant sources.

Estudio y análisis de las necesidades computacionales de un parque eólico

[ES] La energía eólica es una de las fuentes de energía renovable más importante hoy día con un continuo crecimiento a nivel mundial. España también ha apostado por las renovables y más concretamente por la energía eólica, materializándose con importantes instalaciones en gran parte de las comunidades autónomas entre ellas, Canarias. Con la realización de este trabajo se pretende estudiar el potencial eólico disponible en la zona donde se pretenda instalar o mantener un parque eólico, empleando para ello la ayuda de un supercomputador, el cual se encargará, por medio de un software de predicción meteorológica, que ayudarán en la decisión de dónde ubicar un parque eólico y, posteriormente, en la fase de explotación, predecir la potencia que un parque eólico inyectará en la red eléctrica con la antelación suficiente para que permita planificar las centrales de reserva de generación de energía tradicional u otras acciones que se consideren de interés. Durante el desarrollo del trabajo emplearemos el software “WRF” de predicción meteorológica. Esto generará un alto coste computacional y es por lo que proponemos realizar los cálculos empleando la ayuda de un supercomputador. Para concluir el trabajo mostraremos las características del supercomputador Atlante, situado en Las Palmas de Gran Canaria, y analizaremos el coste que le supondría a una empresa, la compra o el alquiler de un supercomputador.