Lithium-Beryllium-Boron Evolution: From Meneguzzi, Audouze and Reeves 1971 Up to Now

We review the main sources of LiBeB production and show that a primary mechanism is at work in the early Galaxy involving both ejection and acceleration of He, C and O at moderate energy, which by nuclear interaction with H and He produce light isotopes. The precise measurement of the Be abundance at [Fe/H] = -3.3 and of $^6Li$ in halo stars find an explanation in this framework. Thus, the preservation of $^6Li$ in the atmosphere of metal poor stars implied, points toward the fact the Spite plateau reflects the primordial value of Li. Consequently, it can be used as a baryodensitometer.Comment: 6 pages, no figure, invited talk, to be published in World Scientific, Proceedings of the conference "Cosmic Evolution" in the honor of Jean Audouze and James W. Truran, held at the Institut d'Astrophysique de Paris, Franc

High energy cosmic ray signature of quark nuggets

It has been recently proposed that dark matter in the Universe might consist of nuggets of quarks which populate the nuclear desert between nucleons and neutron star matter. It is further suggested that the Centauro events which could be the signature of particles with atomic mass A approx. 100 and energy E approx. 10 to 15th power eV might also be related to debris produced in the encounter of two neutron stars. A further consequence of the former proposal is examined, and it is shown that the production of relativistic quark nuggets is accompanied by a substantial flux of potentially observable high energy neutrinos

Early Nucleosynthesis(Proceedings of Japan-France Seminar on Chemical Evolution of Galaxies with Active Star Formation)

After a brief summary of our present knowledge of the primordial abundances of the very light elements (D, ^3He, ^4He and ^7Li), the simplest model of primordial nucleosynthesis is presented. Its implications on the baryonic density of the Universe and the number of neutrino (lepton) families are outlined. Recent models dealing with specific scenarios of chemical evolution of our Galaxy and with the possible presence of non baryonic particles (massive neutrinos, gravitinos, photinos, quark nuggets...) are also discussed

Mobilité résidentielle et stratégie de subsistance dans le Magdalénien du Bassin Parisien

22 p.International audienceThe Upper Palaeolithic societies are commonly interpreted as complex societies that are organized according to a logistical residential system with base camps and satellite camps for hunting, getting raw materials, storage etc. by comparison with hunters-gatherers societies of high latitudes. Ethno-archaeological comparisons and the interpretation of the archaeological data on the hunting camps of the site of Verberie (Oise) and other Magdalenian sites of the Paris Basin permit us to argue that, on the contrary, the Magdalenians of the Paris Basin were organized according to a foraging strategy in relation to a high residential mobility. The eight successive hunting camps set up at Verberie during the fall reindeer migration were residential family camps at the same time. The lack of storage pits, the lack of domestic animals for carrying loads and the access to a plentiful game – horse – that was present all year round in the area in addition to the migrating reindeer are the main features that give the Magdalenians their unquestionable originality. If a comparison must be made, it would be with the “Serial Specialists” of Northern Canada obliged to frequently move their residence in order to avoid depleting the local game.Les sociétés du Paléolithique supérieur sont interprétées comme des sociétés complexes utilisant un système de résidence logistique comprenant des campements de base et des camps satellites pour la chasse, le stockage, l'acquisition des matières premières etc. à l'image des sociétés de chasseurs-cueilleurs des hautes latitudes. Des comparaisons tirées d'études ethno-archéologiques et l'interprétation des données archéologiques concernant les campements de chasse du site de Verberie (Oise) et des autres sites magdaléniens du Bassin Parisien permettent d'argumenter qu'au contraire, les Magdaléniens du Bassin Parisien étaient organisés selon une stratégie de « foragers » liée à une forte mobilité résidentielle. Les huit camps de chasse successifs établis à Verberie durant la migration d'automne des rennes sont aussi des campements résidentiels familiaux. Les principaux traits qui donnent une indéniable originalité aux Magdaléniens et les empêchent d'adopter une stratégie résidentielle logistique sont d'une part l'absence de structures de stockage et d'animaux de bât. Mais plus que ces deux handicaps, c'est l'accès, en sus du renne, à un gibier abondant, le cheval, présent dans la région à toutes les saisons, qui les différencient des chasseurs du Grand Nord américain ou des chasseurs sibériens. S'il faut les rapprocher d'une catégorie particulière de chasseurs-cueilleurs, ce serait plutôt celle des Serial Specialists contraints à une forte mobilité résidentielle pour ne pas épuiser les ressources en gibier local aux environs des campements

Chasseurs de renne d'hier et d'aujourd'hui

Binford's ethnoarchaeological research on the Nunamiut of Alaska and F. David, C. Karlin and S. Beyries' research on several populations of Siberian reindeer hunters-herders allow the construction of a model of reindeer carcasses processing and its spatial configuration. Similarly, building models of hide processing makes it possible to propose hypotheses about the division of labor at the Magdalenian site of Verberie.Les études ethno-archéologiques faites par L. Binford chez les Nunamiut d'Alaska et par F. David, C. Karlin et S. Beyries chez différentes populations d'éleveurs-chasseurs de rennes de Sibérie permettent de modéliser le traitement des carcasses de renne et son inscription dans l'espace. On peut à partir de là reconstituer ces mêmes opérations dans un campement de chasseurs magdaléniens du 13e millénaire BP. De même, à partir de la modélisation du travail des peaux, il est possible de proposer des hypothèses quant à la répartition des tâches dans le site magdalénien de Verberie

The first generation of stars: first steps towards chemical evolution of galaxies

We argue that extreme metal-poor stars show a high dispersion in metallicity, because their abundances are the outcome of very few supernova events. Abundance anomalies should appear because of the discrete range of progenitor masses. There is a natural metallicity threshold of Z/Z_\odot\sim 10^{-4} below which one would expect to find very few, if any, halo stars. Similar reasoning is applied to lower mass systems, such as metal-poor compact blue galaxies and Lyman alpha absorption line clouds seen towards high redshift quasars, where a somewhat higher threshold is inferred

Lithium-6 : Evolution from Big Bang to Present

The primordial abundances of Deuterium, he4, and li7 are crucial to determination of the baryon density of the Universe in the framework of standard Big Bang nucleosynthesis (BBN). li6 which is only produced in tiny quantities and it is generally not considered to be a cosmological probe. However, recent major observational advances have produced an estimate of the li6/li7 ratio in a few very old stars in the galactic halo which impacts the question whether or not the lithium isotopes are depleted in the outer layers of halo stars, through proton induced reactions at the base of (or below) the convective zone. li6 is a pure product of spallation through the major production reactions, fast oxygen and alphas interacting on interstellar H, He (especially in the early Galaxy). The rapid nuclei are both synthesized and accelerated by SN II. In this context, the \li6 evolution should go in step with that of beryllium and boron, recently observed by the Keck and HST telescopes. Li6 adds a new constraint on the early spallation in the Galaxy. In particular, if confirmed, the Li6/Be9 ratio observed in two halo stars (HD 84937, BD +263578) gives strong boundary conditions on the composition and the spectrum of the rapid particles involved. We show that Li6 is essentially intact in halo stars, and a fortiori \li7. We can define a range of the Li6 abundance in the very early Galaxy consistent with Big Bang nucleosynthesis (5.6 10(-14) to 3. 10(-13) . Following the evolution at increasing metallicity, we explain the abundance in the solar system within a factor of about 2.Comment: 16 pages, 4 figure