Synthèse et structure de la poly-O-carbobenzoxy L- tyrosine et de copolymères de O-carbobenzoxy L-tyrosine et de glutamate de benzyle ou d'aspartate de benzyle

The optical rotatory dispersion of copolymers of O-carbobenzoxy-L -tyrosine and benzyl L (or D )-glutamate as well as benzyl L -aspartate, dissolved in nonpolar solvent, has been studied. Moffitt's equation permits the determination of b₀ coefficients whose variation, with varying composition in amino acid residues, suggests that the molecules of poly-O-carbobenzoxy-L -tyrosine have a helical structure similar to that of poly-(benzyl L -glutamate). Results obtained from infrared spectroscopy and x-ray diffraction show that the copolymers possess a helical conformation in the solid state, even when they are very rich in carbobenzoxy-L -tyrosine residues. The value of the b₀, coefficient for poly-O-carbobenzoxy-L -tyrosine may be explained by a regular stacking of the chromophore groups around the helical backbone. The ordering of the molecules of this polymer in a purely helical structure seems favored by the insertion of a small number of foreign residues in the polypeptide chain.     

Espaces de réclusion et de rassemblement et expression graphique au Néolithique

Space is an inescapable data to analyse the schematic graphic expression in the Neolithic age and the practices, which are linked with it. A sign has meaning according to its place on the wall, in the shelter and in the area of decorated sites. We suppose that these painted shelters, and widely, the space where they are included, are visited during transition rites. Some of these sites have probably been used for persons in cloistered status. Others shelters are more areas for the gathering of an important group of men. We think that cloistering and gathering are adaptable with the diversity of environment. The Van Gennep's explanation of transition rites in three parts and the spatial analysis allow us to explain the transition and transformation of men on the decorated sites.     

Le Protoaurignacien : première culture de l'homme moderne de Provence et Ligurie

G. Laplace defined the Protoaurignacian in Liguria (“abri Mochi”) as the earliest occurrences of Upper Paleolithic in Italy. Stratigraphic sequences in Var exemplify that the Protoaurignacian is the first sequence of Upper Paleolithic in Provence and widely different from classic Aurignacian defined in southwestern France. Recorded in Languedoc-Roussillon, that one is documented in some other stratigraphic sequences from Monaco to southern Spain (“cueva del boquete de Zafarraya”). The Protoaurignacian argue that first modern humans arrived and occupied all along the Mediterranean coasts from Gibraltar to Toscana.     

Stratégie de débitage et mode de façonnage des industries du Paléolithique inférieur en Chine et en Europe entre 1 Ma et 400 000 ans: Ressemblances et différences de la culture de l’homme de Yunxian et Acheuléen européen

These stone tools from Yunxian with other Lower Paleolithic sites in South China, for example, the site Lantian (Shanxi, China) and the site Bose (Guangxi, China), indicates that there are many common characteristics among these industries. There are choppers, chopping-tools, picks, hand-axes, cleavers and scrapers. Long ago we thought that there are not hand-axes in China. In fact, there are lots of hand-axes in China and these hand-axes existed more earlier than those in Europe. The hand-axe appeared in China before 800,000 years old and it barely arrived in Europe before 600,000 years old. The quaternary deposits of the site of Yunxian Hominid (Hubei, China) are at least dated to 800,000 years old. A large quantity of lower Paleolithic material was discovered. The types of the tools are choppers, picks, scrapers, hand-axes and cleavers. The pebbles tools make up the majority of the implements. Small flake tools are relatively rare. The lithic industries comparison of the two regions has help us to know the cultural evolution in China and Europe.