Andris Ambainis was supposed to spend the fall at MSRI in Berkeley but instead is enjoying his native Latvia. When Manindra Agrawal came to Boston last month to talk about his primality algorithm, he was supposed to bring along his student co-authors. Instead he came alone.
Worries about terrorism have caused the US government have made them more cautious about issuing visas and this has slowed down the visa process tremendously. Visa problems have always been a thorn for academics but this fall seems particularly bad.
I understand the need to be careful but when science is hindered by politics nobody is a winner.