Contents

29 April 2014
Vol 7, Issue 323

About The Cover

Cover image expansion

Online Cover This week features a Research Article that describes how the worm Caenorhabditis elegans can sense and move toward low concentrations of a molecule but sense and move away from high concentrations of the same molecule. The image shows an artist's rendition of the tracks that the nematodes make as they migrate. [Image: Chris Bickel, AAAS]