Sleep 1980

Trends in timing of sleep in the general population of Norway: 1980 to 20001.

The aim of the current study was to examine whether the timing of sleep have changed over the last two decades. As part of a general survey of activities throughout the 24-hr. cycle, collected in 1980, 1990, and 2000 by Statistics Norway, information on sleep timing was obtained for every 15-min. interval for 1 wk. All three samples were representative of Norwegians. The age span was from 16 to...

Dev104760 1971..1980

The ability to image cells live and in situ as they proliferate and differentiate has proved to be an invaluable asset to biologists investigating developmental processes. Here, we describe a Spectrum of Fates approach that allows the identification of all the major neuronal subtypes in the zebrafish retina simultaneously. Spectrum of Fates is based on the combinatorial expression of differentl...

Computational Complexity Since 1980

The field of computational complexity is reaching what could be termed middle age, with over forty years having passed since the first papers defining the discipline. With this metaphor in mind, the early nineteeneighties represented the end of adolescence for the area, the time when it stopped wondering what it would be when it grew up. During the childhood period of the sixties, research cent...

Amniocentesis Prior to 1980

The extraembryonic membranes [5] that surround and originate from the embryos of vertebrates such as birds [6], reptiles, and mammals are crucial to their development. They are integral to increasing the surface area of the uterus [7], forming the chorion [8] (which in turn produces the placenta [9]) and the amnion [10], respectively. The amnion [10] will ultimately surround the embryo in a flu...

Book Reviews, Winter 1980