Fish assemblages associated with extractive platforms were surveyed, for the first time, using traditional fishing surveys (bottom gill net) and an underwater visual census (UVC) technique in order to test the effectiveness and to identify strengths and weaknesses of both methods. The study was carried out during three seasons at two offshore gas platforms (Eleonora and Squalo C) located in the central Adriatic Sea. Both methods recorded a similar number of fish species although with only eight species in common, thus supplying complementary information and a good estimate of the total fish species richness (39) associated with these gas platforms. The use of innovative techniques, such as UVC, to explore the inner part of the platforms, allowed the censusing of several cryptobenthic species, mostly Blennidae (8 species), never recorded during previous studies. Even if both methods were able to detect temporal variability, only the UVC technique was able to highlight spatial changes between platforms, demonstrating their high efficiency regarding the quality of the scientific information supplied. The innovative method of studying biodiversity presented in this study appears to be highly reproducible and suitable for monitoring fish diversity in artificial and very complex habitats like gas platforms.

Se estudiaron, por primera vez, las comunidades de peces asociadas con plataformas extractivas mediante muestreos pesqueros tradicionales (red de enmalle de fondo) y una técnica de censos visuales submarinos para determinar la eficacia e identificar las fortalezas y debilidades de los dos métodos. El estudio se realizó durante tres estaciones del año en dos plataformas gaseras marinas (Eleonora y Squalo C) localizadas en el Mar Adriático central. Los dos métodos registraron una cantidad similar de especies ícticas, aunque solamente ocho especies en común, suministrando información complementaria y un buen cálculo de la riqueza total de las especies ícticas (39) asociadas con las plataformas gaseras. El uso de técnicas inovadoras, como los censos visuales submarinos, para explorar el interior de las plataformas permitió el censo de varias especies criptobentónicas, generalmente Blennidae (8 especies), que no se habían registrado en estudios anteriores. Aunque con los dos métodos se logró detectar la variabilidad temporal, sólo los censos visuales distinguieron los cambios espaciales entre las plataformas, demostrando así la calidad de la información científica suministrada. Este método inovador para estudiar la biodiversidad parece ser altamente reproducible y apropiado para observar la diversidad de peces en hábitats artificiales y complejos como lo son las plataformas gaseras.

Propõe-se um modelo simples de oscilador harmônico para descrever a potência mecânica envolvida na locomoção humana. Neste contexto, considerando parâmetros antropométricos de um indivíduo padrão, mostramos como calcular as curvas de velocidade x potência na caminhada de um humano. O modelo proposto explica a conhecida lei de Margaria, segundo a qual o custo de uma corrida (independente da velocidade) é fixo e vale 1 kcal/(kg km). O modelo inclui os efeitos de um aclive (ou declive) pouco acentuado e o efeito devido à resposta mecânica da superfície sobre a qual se caminha. Os resultados obtidos via modelo na presençe um subida/descida concordam qualitativamente com os resultados experimentais obtidos por A. Leonardi et al.

A simple harmonic oscillator model is proposed to describe the mechanical power involved in human locomotion. In this framework, by taking into account the anthropometric parameters of a standard individual, we are able to calculate the speed-power curves in human walking. The proposed model accounts for the well known Margaria's law in which the cost of human running (independent from the speed) is fixed to 1 kcal/(kg km). The model includes the effects of a gentle slope (either positive or negative) and the effect due to the mechanical response of the walking surface. The model results obtained in the presence of a slope are in qualitative agreement with the experimental data obtained by A. Leonardi et al.