In this paper, we study the binary relations R on a nonempty N-set A which are hindependent and h-positive (cf. the introduction below). They are called homothetic positive orders. Denote by B the set of intervals of R having the form [r,+∞[ with 0 < r ≤ +∞ or ]q,∞[ with q ∈ Q≥0. It is a Q>0-set endowed with a binary relation > extending the usual one on R>0 (identified with a subset of B via t...

Résumé Les fibrations de Ganea permettent la définition de la catégorie de Lusternik et Schnirelmann d’un espace. Dans ce travail, nous assouplissons leur procédé de construction, obtenant ainsi une justification topologique à l’existence des modèles algébriques rationnels introduits par Félix-Halperin et Lemaire. Pour ce faire, nous sommes amenés à préciser l’application induite en homologie p...

Midbrain dopaminergic (mDA) neuron development has been an intense area of research during recent years. This is due in part to a growing interest in regenerative medicine and the hope that treatment for diseases affecting mDA neurons, such as Parkinson’s disease (PD), might be facilitated by a better understanding of how these neurons are specified, differentiated and maintained in vivo. This ...

Dept. of Medicine, TN Medical College & BYL Nair Ch. Hospital, Mumbai 400 008 C Nicolle was born in Rouen, France, to a practising physician. He received his medical education in Rouen and completed his graduation from the hospital in Paris. In 1893, he further studied in the Pasteur Institute of Paris, under the direction of Metchnikoff and Roux. In 1902, he was appointed the first director of...