ISTANBUL A US Homeland Security agent testified Tuesday that he was instructed not to inform a Turkish doctoral student who was detained by immigration agents this March that her visa had been revoked. “It was the determination made that she would not be” made aware “that her visa had been revoked. We did not plan on alerting her,” Patrick Cunningham testified in federal court. In the case of Ozturk, a Tufts University graduate student, her visa was revoked without notice after she co-authored