The U.S. Defense Department has backed off a proposal to require significant new controls, including security badges and restricted laboratory access, for foreign researchers working with sensitive technology at American universities. Instead, the agency said it would require researchers working on its contracts to follow existing \"export control\" rules of the U.S. Commerce and State Departments, which are designed to keep technology and weapons important to national security from falling into the hands of terrorists or spies. The Defense Department\'s announcement came after universities and other research advocates directed a volley of complaints at the agency\'s original proposal. University officials predicted that it would interfere with valuable research and create an expensive, duplicative bureaucracy within academic laboratories.