Science: Theoretical astrophysicist Yousef Sobouti, the founder-director of Iran’s Institute for Advanced Studies in Basic Sciences in Zanjan, was dismissed last week by the Iranian Ministry of Science. In addition, over the past month, at least 17 other leaders of academic and scientific institutions have been replaced. As Science‘s Yudhijit Bhattacharjee reports here and last April, many believe that the regime of Iranian President Mahmoud Ahmedinijad has been weeding out political dissidents in Iran’s academic and scientific institutions since his election in 2009. This internal pressure comes at a bad time for Iranian science, as UN sanctions make it harder for scientists there to obtain equipment and attend meetings.