RT Journal Article SR Electronic T1 SCIENTIFIC JOURNALS AND ARTICLES JF Science JO Science FD American Association for the Advancement of Science SP 760 OP 761 DO 10.1126/science.39.1012.760-a VO 39 IS 1012 YR 1914 UL http://science.sciencemag.org/content/39/1012/760.2.abstract AB