[en] The author discusses the definition of an equitable division rule of the global effort of greenhouse gases emissions decrease, the research of the economic efficiency, the flexibility mechanisms and the emissions trading. (A.L.B.)

[en] After having summed up the different old or new units, used in radioactivity and radioprotection, the origins of atmospheric radioactivity are reported. Next the authors deal with the air content in radon, thoron and their radioactive descendants, insisting on the variations of the radon air content and on the radioactive balance between radon and its descendants. Then a few notions concerning the natural radioactive aerosol are developed: electric charge state, granulometric distribution. The possible effects of natural atmospheric radioactivity on man are studied with a distinction between inner irradiation and outer irradiation, an average assessment is shown. Finally the important problem of radon in inhabitations is approached

[en] Everybody knows that the radioactivity was discovered, 100 years ago, by the Frenchman Henri Becquerel at Paris, in Feb. 1896, stemmed from the discovery of X-rays by Roentgen in the preceding year. In 1899, Rutherford was able to show the existence of α and β rays, and in 1900 Villard showed the presence of a third class of rays, the γ rays. The discovery of the rare radioactive gas radon is attributed to P. and M. Curie in 1898 and F. Dorn in 1900. Thoron (²²⁰Rn) was discovered by Rutherford and Owens in 1899-1900 and Actinon (²¹⁹Rn) by Debierne and Geisel about the same time. The radon's radiotoxicity was studied in France since 1904 by Bouchard and Balthazard and in 1924 it was formulated the hypothesis that the great mortality observed in the uranium miners of Schneeberg in Germany and Joachimsthal in Czechoslovakia was maybe due to the radon. But, in fact, Elster and Geitel were the first to see that the radioactivity is present in the atmosphere in about 1901. After this date, many investigations were made (M. Curie, for example), but it is during the fifties and, of course, until today that the most numerous works were developed. In this paper, we speak about the researches of the after second war pioneers: Evans, Wilkening, Kawano, Israel, Junge, Schuman, Bricard... Renoux, Madelaine, Blanc, Fontan, Siksna, Chamberlain, Dyson, Nolan, etc. and the works developed later. Finally, we reach to the nineties, period where the works are particularly directed in the aim of radon and radon progeny indoor, with in particular, many works effectuated in France. (author). 78 refs., 17 figs., 2 tabs

[en] The paper concerns natural atmospheric radioactivity - i.e. from Radon 222 and Radon 220 and their short-lived daughters. Values of radon and thoron concentrations in the air are given, as well as the state of the balance between radon and its daughters. Results are presented of the size distribution of natural radioactive aerosols for the N.E. and S.W. of France. Figures are also given for the average exposures to natural radiation sources per year. The problem of radon 222 and daughters in doors is briefly discussed - the average value in french homes (40 Bq m^-3) is similar to other countries. Finally external exposure to natural radiation in different parts of France is shown on a map. (U.K.)

[en] Size distribution of short lived radon daughters is considered as a fundamental parameter in radiation protection in so far as about 40% of human exposure is due to inhalation of such radioactive particles, in mines as well as in indoor environments. Many experiments have been carried out in various conditions: controlled atmospheres, uranium mine atmospheres, atmospheric air, and more recently in houses because of the increasing interest in exposure to natural radiation. From an experimental point of view, previous measurements dealt with the cumulative size distribution of radon progeny alpha activity. Then, in spite of the difficulty in comparing data of different investigators, it was often found that a significant part of the activity was associated with particles above 0.1 μm in diameter. Otherwise, a bimodality was often observed in the case of airborne radioactive particles. The attachment of small radioactive ions or atoms produced by the radon decay on ambient particles has been studied. Differences arise in the calculation of the attachment coefficient and in the choice of the natural particle size distribution. This paper presents our investigation in this field by studying the theoretical and experimental aspects of the radon daughter behaviour in a cylindrical vessel simultaneously. (author)

[en] At the beginning of the last decennium it was well understood that the balance of the impurity content of a magnetically confined plasma is dominated by interaction between plasma particles and the material walls. Accordingly, a systematic effort was oriented towards the study of the plasma-surface interaction and of the relevant atomic processes of ion-atom collisions. Atomic processes involving hydrogen, helium, carbon, oxygen and metallic impurities were of first priority in this domain. Systematic evaluation and compilation of cross sections relevant to fusion was already initiated by C.F. Barnett, founder of the ORNL Controlled Fusion Atomic Data Centre. The status of the atomic data base for reactions occurring mostly in the plasma core or concerning mainly the plasma heating by energetic ion beams has been reviewed elsewhere. Studies of H and He collisions involving metallic impurities or oxygen have been recently made available. The status of such data was recently reviewed. Here we concentrate to our calculations in progress of collision cross sections for the carbon ions colliding with hydrogen and helium. The CTMC method was used for calculating total ionisation and one electron capture cross sections for H-C^q+ collisions in the energy region of 10 to 5000 and of 1 to 1000 keV/u correspondingly. (author) 15 refs., 6 figs

[en] Autoradiographic studies, at the light and electron microscope level, demonstrate that spermatid nuclei of the Locust Locusta migratoria incorporate ³H-acetate, especially during the first stages of spermiogenesis. The highest level of acetate incorporation is observed during stage II of spermiogenesis. During this stage and the following, the spermatid nucleus undergoes a number of structural and chemical modifications: chromatin decondenses and somatic histones are progressively replaced by newly synthesized arginine-rich proteins. Therefore, the higher degree of acetylation of nuclear components coincides with chromatin decondensation and precedes the protein transition occurring in later stages. Cytochemical and autoradiographic tests have been realized so as to localize ³H-acetate in the nuclear components. Trichloracetic acid was used at various concentrations: the action of hydrochloric acid, pronase and DNase was also tested. The results support the idea that proteins, and among them histones, are the only nuclear components to be acetylated during spermiogenesis. Thus, histone acetylation seems to play an important role in modulating histone-DNA interactions and allowing histone replacement

[en] Screen-printing is used to prepare thick films of stabilized zirconia and doped ceria, with different shapes of electrodes. This technique gives an electrode area to electrolyte thickness ratio from 1 to 2 orders of magnitude higher compared to that of conventional pellets. The paper gives some details on the preparation methods, and preliminary results on electrode polarization measurements on yttria-stabilized zirconia and gadolinia-doped ceria at temperatures as low as 620 K. Below 750 K and 50 Hz, the impedance of the cells is entirely due to the metal/oxide/gas interface, hence this method could lead to a better understanding of the electrode processes and catalysis mechanisms. (author)

[en] The centenary of the discovery of X-rays is the occasion to summarize the history of X-ray absorption spectroscopy (XAS) and its development on synchrotron radiation sources, to give the underlying principles and to illustrate the possible uses of this spectroscopy by three examples: (a) the structural characterization of disordered spin transition coordination compounds by EXAFS spectroscopy; (b) the ligand binding to vitamin B₁₂ by XANES spectroscopy; and (c) the chemical analysis of sulfur compounds included in fly-ashes by low-energy XANES spectroscopy. (authors). 23 refs., 8 figs

[en] Samarium oxide added to zirconium oxide releases lacunar cubic phase whose major electrical conductivity is rendered ionic for low Sm₂O₃ ratios. A n-type electronic conductivity is therefore evidenced