TEHRAN, May 7 — Students at Amir Kabir University fended off club-wielding university security guards on Monday and went ahead with elections for a pro-democracy association. Despite the successful election at Amir Kabir, it is not clear that balloting for student associations will be allowed at other universities. The associations, a powerful center of support and communication among student democracy advocates, are a constant irritant to the government, which seeks to maintain strict control over politics and cultural norms. The University of Science and Industry, where President Mahmoud Ahmadinejad taught before he was elected, has not been permitted to hold...