Effects of Quasi-Static Aberrations in Faint Companion Searches

We present the first results obtained at CFHT with the TRIDENT infrared camera, dedicated to the detection of faint companions close to bright nearby stars. The camera's main feature is the acquisition of three simultaneous images in three wavelengths (simultaneous differential imaging) across the methane absorption bandhead at 1.6 micron, that enables a precise subtraction of the primary star PSF while keeping the companion signal. The main limitation is non-common path aberrations between the three optical paths that slightly decorrelate the PSFs. Two types of PSF calibrations are combined with the differential simultaneous imaging technique to further attenuate the PSF: reference star subtraction and instrument rotation to smooth aberrations. It is shown that a faint companion with a DeltaH of 10 magnitudes would be detected at 0.5 arcsec from the primary.Comment: 12 pages, 10 figures, to appear in Astronomy with High Contrast Imaging, EAS Publications Serie

L’efficacité des programmes de prévention de la toxicomanie axés sur les familles

Cette recension des écrits examine l'efficacité de programmes de prévention des toxicomanies auprès des familles. De nombreux travaux soulignent le rôle déterminant des familles dans la transmission des habitudes de consommation. De plus, selon plusieurs intervenants, la famille constitue un milieu propice pour l'instauration de tels programmes de prévention. Cet article propose une analyse critique de ces programmes. Sont présentés les facteurs de risque liés à l'abus de substances chez les jeunes, puis les programmes visant la famille dont la stratégie est l'information, ceux qui font appel à des stratégies multiples et ceux qui visent les parents les plus à risque. Une critique méthodologique des études évaluatives est présentée. Les auteurs concluent par des recommandations.This literature review examines the efficiency of drug addiction prevention programs centered on families. Many studies underline the determining role of families in the transmission of consumption habits. Moreover, according to many intervenors, the family constitutes a favourable milieu to institute these prevention programs. This article proposes a critical analysis of these programs. The risk factors related to substance abuse with youth are first presented followed by information strategy programs aimed at families, multiple-strategy programs as well as programs aimed at parents who are considered at high risk. A methodological review of evaluative studies is presented. The authors conclude with recommendations.Este censo de escritos examinarâ la eficacia de los programas de prevenciôn con las familias, de la toxicomania. Numerosos trabajos subrayan el papel déterminante de las familias en la transmisiôn de hâbitos de consumo. Ademâs, segun varios trabajadores, la familias constituye un medio propicio para la instauration de taies programas de prevenciôn. Este artïculo propone un anâlisis crîtico de esos programas. En principio se presentan los factores de reisgo ligados al abuso de sustancias en los jôvenes y después los programas hacia las familias cuya estrategia es la information, aquellos que Uaman a estrategias multiples y aquellos dirigidos hacia los padres a riesgo. Una critica metodolôgica de los estudios es presentada. Los autores concluyen con recomendaciones

Correspondence from a UMaine Alumnus

Typewritten letter from Jon H. Towle expressing support for the Civil Rights of the members of the Wilde-Stein Club