Rats equipped with radios that transmit their brainwaves could soon be helping to locate earthquake survivors buried in the wreckage of collapsed buildings. In a project funded by DARPA, researchers from the University of Florida in Gainesville have implanted electrodes in specific areas of rats' brains and trained the rodents to search for human odor. Rats, which can crawl just about anywhere, have an extremely sensitive sense of smell. Now, for those radios . . .