Tighter immigration rules are causing increased visa delays and refusals for students and postdoctoral fellows seeking entry to the United States, particularly those from China, Russia, India, Pakistan and the Middle East.

Two surveys conducted by the Association of American Universities and the American Physical Society (APS) indicate that student enrolments for 2002-3 have clearly been affected by the terrorist attacks last year. For example, the number of visiting researchers on 'J visas', for exchange visitors, dropped by 11 per cent.

"There is an intrinsic tension between advancing scientific knowledge and national security," says Irving Lerch, director of international affairs at the APS. "Right now, the argument has come down on the side of security, but in the long run that can be deleterious to our research system, economy and security development."

Link to full Nature news story

Source: Nature 420, 349 (2002)