Number 68 (Story #3), February 21, 1992 by Phillip F. Schewe and Ben Stein THE HEAVIEST KNOWN PROTON EMITTERS , radioactive rhenium-160 and tantalum-156, have been discovered in an experiment at the Daresbury accelerator in the United Kingdom. In the experiment, conducted by a Daresbury-Edinburgh-Darmstadt-Liverpool collaboration, nickel ions were smashed into a cadmium target, creating at times rare nuclei which could be detected in a special mass separator device. Proton emission is a rare form of radioactivity, observed for the first time only in the early 1980's. It is of interest because it offers information on the structure of rare neutron-deficient nuclides. (R.D. Page et al., Physical Review Letters, 2 Mar. 1992.)