Arctic quaternary ostracods and their use in paleoreconstructions

The paper deals with original and published data on fossil ostracodal assemblages from the Eurasian Arctic Kara, Laptev and Chuckchi seas. As a whole, six ecologically different assemblages were distinguished (freshwater, brackish water, marine of the inner, middle and outer shelves and upper continental slope), they replace each other upcore reflecting a gradual increase in water depth and distance from the coast. These assemblages are stable in the entire Arctic region and can be used for interpretation of environments in different Arctic areas

Application of Phase-Averaging Methods to Sweeping Supersonic Jets

This paper examines various methods for phase averaging the flowfield of a sweeping supersonic jet emanating from a scaled fluidic oscillator. Determination of the phase-averaged flowfield is challenging, especially at high oscillation frequencies where there is a jitter in the periodicity caused by its inherent fluid dynamics. Several phase-averaging approaches (including mathematical, signal processing, and phase-lock techniques) applied to time-resolved schlieren images of the flowfield are described. Criteria for evaluation are based on the image distribution per phase bin, the centerline intensity profile of the phase-averaged schlieren image, and the cross correlation of the images with the timeaveraged reference image. Examination of the different methods based on the criteria shows that the zero-crossing method is sufficiently accurate and most suitable for the naturally oscillating flowfield investigated in this study. Although the phase-locked approach works well at specific phase angles, overall, it is found unsuitable for the current test conditions. The zero-crossing method applied to a sweeping supersonic jet schlieren reveals shock structure distortion when switching directions in the oscillation cycle. Results indicate that the zero-crossing method described in this study can also be extended to other non-time-resolved quantitative and qualitative flowfield measurement techniques using a simultaneously acquired time-resolved reference signal

Kaké (Ibrahima Baba) : Les Noirs de la diaspora

Elisabeth Léo. Kaké (Ibrahima Baba) : Les Noirs de la diaspora. In: Revue française d'histoire d'outre-mer, tome 65, n°239, 2e trimestre 1978. p. 264

Fonctions discriminantes, formules pour le nombre de classes, et unites elliptiques; le cas des corps de fonctions (associes a des courbes sur des corps finis)

SIGLEINIST T 77602 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc