Rapports asymétriques entre Indiennes et Blancs dans le Nord canadien*

This paper examines the nature of the relations between Indian women and white men developed on the basis of racial categories and structural inequalities between whites and Indians. The author argues that social prestige is not the basic motivation in intermarriage. The author emphasizes the importance of an analytical distinction between choices and preferences. Finally, this paper examines various causes of endogamy within the Indian group. Cet article examine la nature des relations entre femmes indiennes et hommes blancs engendrées par la catégorisation raciale et les inégalités structurales entre Blancs et Indiens. L'auteur soutient que la recherche de prestige social n'est pas nécessairement la principale motivation des unions interethniques. L'auteur souligne l'importance d'une distinction analytique entre les choix et les préférences. Finalement, cet article examine certaines causes d'endogamie au sein du groupe indien.     

A statistical approach to the resolution of point sources

SUMMARY The Rayleigh criterion in optics states that two point sources of equal intensity are 'barely resolved' when the maximum of the diffraction pattern of one source overlaps the first minimum of the diffraction pattern of the second source. Although useful for rough comparisons of optical systems, such a criterion does not take into account the randomness in the detection process and does not tell whether sources can actually be distinguished. We present a statistical approach that addressed these issues. From quantum optics, the photon counts in the pixels are independent Poisson random variables with means that depend on the distance 2theta between the sources. Resolving the sources corresponds to testing H0: theta =0 vs Ha: theta >0, under conditions that make the information number zero at theta =0. We define resolution as the (asymptotic) power function of the likelihood ratio test rather than as a single number. The asymptotic distribution of the test statistic is derived under H0 and under contiguous alternatives. The results are illustrated by an application to a sky survey to detect binary stars using the Hubble space telescope.