A reduction in sleep amount from late childhood through the second decade has long been known; however, the weight of current evidence holds that sleep need does not decline across this span. This article will describe how the loss of sleep through adolescence is not driven by lower need for sleep but arises from a convergence of biologic, psychological, and socio-cultural influences.

Over the past decade, leading epidemiologists have noted the importance of social factors in studying and understanding the distribution and determinants of disease in human populations; but to what extent are epidemiologic studies integrating genetic information and other biologic variables with information about individual-level risk factors and group-level or societal factors related to the ...

Life evolved on earth slowly over a few billions of years. During this time, and before, the earth has been rotating around its own tilted axis and simultaneously revolving around the sun. Thus, it is no surprise that the periodic environmental consequences of the rotation (day and night), the tilt (changing day length) and of the revolution (seasons) should influence life-forms right from thei...

Microarray technology has been applied to a variety of different fields to address fundamental research questions. The use of microarrays, or DNA chips, to study the gene expression profiles of biologic samples began in 1995. Since that time, the fundamental concepts behind the chip, the technology required for making and using these chips, and the multitude of statistical tools for analyzing t...

Fitts's law is one of the most well-established principles in psychology. It captures the relation between speed and accuracy in performed and imagined movements. The aim of this study was to determine whether this law also holds during the perception of other people's actions. Subjects were shown apparent motion displays of a person moving his arm between two identical targets. Target width, t...