Major influencing factors of indoor radon concentrations in Switzerland.

PURPOSE: In Switzerland, nationwide large-scale radon surveys have been conducted since the early 1980s to establish the distribution of indoor radon concentrations (IRC). The aim of this work was to study the factors influencing IRC in Switzerland using univariate analyses that take into account biases caused by spatial irregularities of sampling. METHODS: About 212,000 IRC measurements carried out in more than 136,000 dwellings were available for this study. A probability map to assess risk of exceeding an IRC of 300 Bq/m(3) was produced using basic geostatistical techniques. Univariate analyses of IRC for different variables, namely the type of radon detector, various building characteristics such as foundation type, year of construction and building type, as well as the altitude, the average outdoor temperature during measurement and the lithology, were performed comparing 95% confidence intervals among classes of each variable. Furthermore, a map showing the spatial aggregation of the number of measurements was generated for each class of variable in order to assess biases due to spatially irregular sampling. RESULTS: IRC measurements carried out with electret detectors were 35% higher than measurements performed with track detectors. Regarding building characteristics, the IRC of apartments are significantly lower than individual houses. Furthermore, buildings with concrete foundations have the lowest IRC. A significant decrease in IRC was found in buildings constructed after 1900 and again after 1970. Moreover, IRC decreases at higher outdoor temperatures. There is also a tendency to have higher IRC with altitude. Regarding lithology, carbonate rock in the Jura Mountains produces significantly higher IRC, almost by a factor of 2, than carbonate rock in the Alps. Sedimentary rock and sediment produce the lowest IRC while carbonate rock from the Jura Mountains and igneous rock produce the highest IRC. Potential biases due to spatially unbalanced sampling of measurements were identified for several influencing factors. CONCLUSIONS: Significant associations were found between IRC and all variables under study. However, we showed that the spatial distribution of samples strongly affected the relevance of those associations. Therefore, future methods to estimate local radon hazards should take the multidimensionality of the process of IRC into account.

Le paysage originel et la nostalgique élégiaque chez Maurice Chappaz

Si le XXe siècle est l'une des époques les plus paradoxales de notre Histoire - à la fois générateur du progrès technique qui devait accroître la qualité de vie des hommes et triste berceau de deux guerres mondiales qui n'ont cessé de multi-plier ravages et victimes pendant presque trente ans -, il a produit un nombre considérable de poètes, qui continuent d'intéresser un large public. Au fil des quelque 580 pages qui constituent le présent volume, les auteurs ont tenté de présenter chacun un poète du siècle dernier, en essayant de mettre en évidence les parti-cularités de sa poétique. Ce livre n'est donc pas une anthologie de tombeaux, mais une approche intellectuelle dont le but est d'éclairer une partie de la vie et de l'oeuvre des 32 poètes traités.

La Fil•loxera i la crisi vitícola a les comarques gironines: 1879-1900

El sector vitícola català, màxim exponent de l'expansió agrícola registrada des d'inici del segle XVIII fins a mitjan XIX, va patir en les darreres dècades de la passada centúria un gran daltabaix. Un insecte desconegut fins aleshores, la fil•loxera, originari del continent americà i contra el qual les vinyes europees no disposaven de cap mena de defensa, va destruir en un marge de cinquanta anys tots els antics ceps d'Europa.

[Louis] Bouchard, [Charles] Denis [coureurs à pied, Prix Maurice Dezeaux, au stade de la Croix-Catelan le 1er juin 1919] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 54167

[Phot. de la maison de Kronenberg à Varsovie en 1878, don de Maurice Chaudoir en 1886]

Donateur : Chaudoir, Maurice (18..-18..?)

1-6-19, Croix-Catelan, prix Maurice Dezeaux, Mourlon gagnant du 60 m : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 54168

[Edward A.] Teschner [américain], gagnant du 100 m [100 yards d'après le Petit Parisien, championnats de l'armée américaine à Colombes, le 1er juin 1919] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 54192