86 research outputs found

    Variability of Active Galactic Nuclei from the Optical to X-ray Regions

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    Some progress in understanding AGN variability is reviewed. Reprocessing of X-ray radiation to produce significant amounts of longer-wavelength continua seems to be ruled out. In some objects where there has been correlated X-ray and optical variability, the amplitude of the optical variability has exceeded the amplitude of X-ray variability. We suggest that accelerated particles striking material could be linking X-ray and optical variability (as in activity in the solar chromosphere). Beaming effects could be significant in all types of AGN. The diversity in optical/X-ray relationships at different times in the same object, and between different objects, might be explained by changes in geometry and directions of motion relative to our line of sight. Linear shot-noise models of the variability are ruled out; instead there must be large-scale organization of variability. Variability occurs on light-crossing timescales rather than viscous timescales and this probably rules out the standard Shakura-Sunyaev accretion disk. Radio-loud and radio-quiet AGNs have similar continuum shapes and similar variability properties. This suggests similar continuum origins and variability mechanisms. Despite their extreme X-ray variability, narrow-line Seyfert 1s (NLS1s) do not show extreme optical variability.Comment: Invited talk given at Euro Asian Astronomical Society meeting in Moscow, June 2002. 20 pages, 4 figures. References update

    Perspectives of family members participating in cultural assessment of psychiatric disorders: Findings from the DSM-5 International Field Trial

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    Despite the important roles families play in the lives of many individuals with mental illness across cultures, there is a dearth of data worldwide on how family members perceive the process of cultural assessment as well as to how to best include them. This study addresses this gap in our knowledge through analysis of data collected across six countries as part of a DSM-5 Field Trial of the Cultural Formulation Interview (CFI). At clinician discretion, individuals who accompanied patients to the clinic visit (i.e. patient companions) at the time the CFI was conducted were invited to participate in the cultural assessment and answer questions about their experience. The specific aims of this paper are (1) to describe patterns of participation of patient companions in the CFI across the six countries, and (2) to examine the comparative feasibility, acceptability, and clinical utility of the CFI from companion perspectives through analysis of both quantitative and qualitative data. Among the 321 patient interviews, only 86 (at four of 12 sites) included companions, all of whom were family members or other relatives. The utility, feasibility and acceptability of the CFI were rated favourably by relatives, supported by qualitative analyses of debriefing interviews. Cross-site differences in frequency of accompaniment merit further study

    New Concepts in Structural Analysis and Design of Double Walled LPRE Thrust Chambers

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