French scientists have unveiled a working prototype of a fully artificial heart which is based on the technology of satellites and airplanes.

The thought of gaining an extra hour of sleep at the end of daylight-saving time may make you giddy with excitement -- but the time switch could also be a trigger for nighttime sleep and daytime alertness problems. Whether you have an existing sleep condition or you've always gotten regular shut-eye, there's a chance you could be hurting once the clock falls back on Sunday.