Cable-Driven Actuation for Highly Dynamic Robotic Systems

This paper presents design and experimental evaluations of an articulated robotic limb called Capler-Leg. The key element of Capler-Leg is its single-stage cable-pulley transmission combined with a high-gap radius motor. Our cable-pulley system is designed to be as light-weight as possible and to additionally serve as the primary cooling element, thus significantly increasing the power density and efficiency of the overall system. The total weight of active elements on the leg, i.e. the stators and the rotors, contribute more than 60% of the total leg weight, which is an order of magnitude higher than most existing robots. The resulting robotic leg has low inertia, high torque transparency, low manufacturing cost, no backlash, and a low number of parts. Capler-Leg system itself, serves as an experimental setup for evaluating the proposed cable- pulley design in terms of robustness and efficiency. A continuous jump experiment shows a remarkable 96.5 % recuperation rate, measured at the battery output. This means that almost all the mechanical energy output used during push-off returned back to the battery during touch-down

Genome size and chromosome number of Micromeria acropolitana (Lamiaceae), a steno-endemic from Greece

Abstract. The chromosome number 2n = 30, and nuclear DNA amount 2C = 0.79 pg, are determined for the first time for Micromeria acropolitana, a rare and endangered species from the Acropolis in Athens, Greece. The plant was considered extinct but rediscovered in 2006, a hundred years later. Its current status in the original habitat is assessed, and proposals for ensuring its survival presented

Demography, Reproductive Biology and Trophic Ecology of Red Coral (Corallium rubrum L.) at the Costa Brava (NW Mediterranean): Ecological Data as a Tool for Management

The precious Mediterranean red coral (Corallium rubrum, L. 1758) is an overexploited gorgonian coral whoose red calcium carbonate skeleton is used in the jewelery industry. This work studies the demography, reproductive ecology and trophic ecology of red coral, and used the data to provide recomendations for its fishery managment and conservation. Five harvested populations at the Costa Brava, Spain, showed a population structure that is significantly shifted towards small/young colonies, compared to a protected population at the Medas Islands Marine Park. Average size and age of colonies in the harvested populations were estimated at 5 cm height and 7.5 years, whereas the species is capable of reaching 50 cm and 100 years. Only a small part of the colonies found show a well developed branching pattern, indicating overexploitation. The reproductive output significantly depends on colony size, with 100 % fertility being reached by colonies of 4 � 6 cm height. Mesoscale geographic variation however had no significant effect on reproductive output. Colonies in deep water spawned slightly earlier than shallow ones, when temperature stratification in summer was particularly pronounced. The main proportion of the diet of corallium rubrum is particulate organic matter (POM), while crustaceans such as copepods played a smaller role due to their infrequent capture. No clear seasonal pattern of the ingestion rate was found, due to the high variablity that may be linked to variability in watermovement. It appears that red coral is a flexible omnivore, able to exploit various trophic situations. Maximum sustainable yield, calculated using the Beverton and Holt model, show an optimal age at first capture of 98 years, while current fishing regulations permit harvesting of colonies that are 11 years old. This results in only a fraction of the calculated maximum yield. Poaching and illegal capture of small colonies appear to be a major problem at the Costa Brava