Parametric Modeling of Human Gradient Walking for Predicting Minimum Energy Expenditure

A mathematical model to predict the optimum gradient for a minimum energetic cost is proposed, based on previous results that showed a minimum energetic cost when gradient is −10%. The model focuses on the variation in mechanical energy during gradient walking. It is shown that kinetic energy plays a marginal role in low speed gradient walking. Therefore, the model considers only potential energy. A mathematical parameter that depends on step length was introduced, showing that the optimal gradient is a function of that parameter. Consequently, the optimal negative gradient depends on the individual step length. The model explains why recent results do not suggest a single optimal gradient but rather a range around −10%

Iuris civilis notae ad vestem seu textile pertinentes : Notes on dress in roman property law.

Roman law considered clothing as a res, as something that could be the object of legal relations, specifically as a res corporalis, a res quae usu consumatur, a res nec mancipi and a res mobilis. These characteristics of vestis as a res were of great practical importance and to a large extent determined the legal regime applicable to the personal property of this type of goods, specifically in regard to possession, right of usufruct and modes of acquiring ownership, as usucapio, occupatio, specificatio and some cases of accessio affecting movables goods: textura and tinctura

Parametric modeling of human gradient walking for predicting minimum energy expenditure

A mathematical model to predict the optimum gradient for a minimum energetic cost is proposed, considering previous results that show a minimum energetic cost when gradient is -10%. The model focus on the variation of mechanical energy during gradient walking. It is shown that kinetic energy has a marginal role in low speed gradient walking. Therefore, the model takes in consideration only potential energy. A mathematical parameter that depends on step length is introduced, showing that the optimal gradient is a function of that parameter. Consequently, the optimal negative gradient depends on the individual step length. The model explains why recent results do not suggest a single optimal gradient but rather a range around -10%

On the dynamic stability of the Cournot duopoly solution under bounded rationality

The most of the oligopolistic models described in the existing literature analyze dynamic processes and the stability of the Nash equilibrium by introducing concrete specifications for the demand and the cost functions. This paper analyzes the dynamic stability of the Cournot-Nash equilibrium in the context of a duopoly using general functions to establish both demand and costs. The condition that guarantees the stability of the Nash equilibrium under the adjustment process implicit in the Cournot’s original model is found to be a key requirement underpinning the dynamic stability of the Cournot-Nash equilibrium regardless of the firms’ expectations scheme. Moreover, this condition is more decisive the higher the degree of rationality of firms

Mechanical properties of nacre and highly mineralized bone

We compared the mechanical properties of 'ordinary' bovine bone, the highly mineralized bone of the rostrum of the whale Mesoplodon densirostris, and mother of pearl (nacre) of the pearl oyster Pinctada margaritifera. The rostrum and the nacre are similar in having very little organic material. However, the rostral bone is much weaker and more brittle than nacre, which in these properties is close to ordinary bone. The ability of nacre to outperform rostral bone is the result of its extremely well-ordered microstructure, with organic material forming a nearly continuous jacket round all the tiny aragonite plates, a design well adapted to produce toughness. In contrast, in the rostrum the organic material, mainly collagen, is poorly organized and discontinuous, allowing the mineral to join up to form, in effect, a brittle stony material

Primer recull anual (1973) de la Comissió de Cetologia de la Institució Catalana d'Història Nataural

This is the first annual rapport of the Comissio de Cetologia of the Instituci6 Catalana d'Historia Natural. This group was founded at the begining of 1973 in order to encourage the study of cetaceans. First of all, the purpose was to record the cetaceans stranded or caught in the area where members are able to work. Because of the center of the group is Barcelona, the geographical limits were the French border in the North and València in the South. Afterwards, it has been possible to extend this area because of the collaboration of some local groups, like these from Alacant (Alicant), Mallorca (Majorca) and Menorca (Minorca). Altogether, 14 specimens have been collected and the most important novelties are the confirmation of the presence of Grampus griseus in the Spanish mediterranean coast and the first record of Balaenoptera borealis in the Western Mediterranean. The number of measurements are not very big because the biometrical work of NORRIS was just known when the activities of the group were in course for half a year. From almost all the specimens anatomical samples and osteological material were collected. All of them are in the Museum of Zoology of Barcelona (Collection of the Comissió de Cetologia of the Institució Catalana d'Història Natural)