A paleobiologist has discovered preserved blood vessels and red blood cells in a 68-million-year-old dinosaur bone.Epigenetics: It seems that diet and lifestyle actually change the expression of our genes.Kryptos: A sculpture called Kryptos in the courtyard of CIA headquarters, contains a code that has yet to be fully broken.Profile: Arlie Petters: A look at Duke University Professor of Mathematics and Physics, and his research in the field of gravitational lensing.