Evolution of Lithium-Beryllium-Boron and Oxygen in the early Galaxy

Oxygen is a much better evolutionary index than iron to describe the history of Lithium-Beryllium-Boron (LiBeB) since it is the main producer of these light elements at least in the early Galaxy. The O-Fe relation is crucial to the determination of the exact physical process responsible for the LiBeB production. At low metallicity, if [O/Fe] vs [Fe/H] is flat, then the production mode is independent of the interstellar metallicity, BeB is proportional to oxygen, i.e. is of primary nature. If not, the production mode is function of the progressive enrichment in O of the interstellar medium, BeB varies rather as the square of O, i.e. is of secondary nature. In the first case, fast nuclei enriched into He, C and O injected by supernovae and accelerated in surrounding superbubbles would explain the primary trend. In the second case, the main spallative agent would be the standard galactic cosmic rays. Calculated nucleosynthetic yields of massive stars, estimates of the energy cost of production of beryllium nuclei, and above all recent observations reported in this meeting seem to favor the primary mechanism, at least in the early Galaxy.Comment: invited review, IAU Symposium, JD8, Manchester, August 2000, New Astronomy Review, in press 6 pages 1 figur

Lithium-Beryllium-Boron and Oxygen in the early Galaxy

Oxygen is a much better evolutionary index than iron to follow the history of Lithium-Beryllium-Boron (LiBeB) since it is the main producer of these light elements at least in the early Galaxy. The O-Fe relation is crucial to the determination of the exact physical process responsible for the LiBeB production. Calculated nucleosynthetic yields of massive stars, estimates of the energy cost of Be production, and above all recent observations reported in this meeting seem to favor a mechanism in which fast nuclei enriched into He, C and O arising from supernovae are accelerated in superbubbles and fragment on H and He in the interstellar medium.Comment: Invited Review, IAU, JD8, Manchester, August 2000, to be published in Highlights of Astronom

Trade Volume Effects of the Euro: Aggregate and Sector Estimates

The gravity model is used to estimate the trade volume effects of the creation of the European currency union. The euro is estimated to have raised the level of aggregate trade between euro countries in 1998-2002 compared to 1989-1997 by 15 per cent and the level of trade with outside countries by 8 per cent. The effect is clearly increasing over time. Estimates for one-digit SITC sectors yield a concentration of effects to highly processed manufactures, indicating that the spillover is caused by increasing vertical specialization across countries.-

Euro Effects on the Intensive and Extensive Margins of Trade

We estimate that the euro has increased trade within the eurozone by about 26 per cent and trade between the eurozone and outsiders by about 12 per cent on average for the years 2002-2005 compared to 1995-1998. The percentage increases were smaller for products that were exported every year during the sample period than for products that were not, indicating significant and substantial effects on the extensive margin of trade. The euro effects were concentrated to semi-finished and finished products, in particular to industries with highly processed products such as pharmaceuticals and machinery.

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

INTEGRAL and Nuclear Astrophysics

We briefly review the fundamentals of nuclear gamma-ray line astronomy (radioactive astronomy), focusing on its role to decipher the intimate physics of supernovae, either immediatly (via $^{56}Co)$ or after a time delay (via $^{44}Ti$). All kinds of supernovae can be in principle tested through their radioactivities and their associated gamma-ray lines. Dedicated to the spectroscopy and imaging of celestial sources in the 15 keV to 10 MeV band, the ESA scientific observatory INTEGRAL will open a golden age of nuclear astrophysics in EuropeComment: Invited review, "Cosmic Evolution", meeting in honor of the 60th birthday of Jean Audouze and Jim Truran, to be published by World Scientific, 6 pages, 1 figur