With protests planned for Thursday's lecture at Purdue University by William Ayers, the university has imposed limits on who may attend the talk, The Journal and Courier  reported. The university will give seats first to student in fields that relate to Ayers' work -- sociology, women's studies, African-American studies, education and child development. Remaining seats will go to those in anthropology, philosophy, political science, communication, history, psychological sciences, foreign languages and literatures and English. University identification cards will be checked at the door. Ayers, a professor at the University of Illinois at Chicago, lectures widely on education reform issues, but some of his campus appearances have been controversial due to his role as a leader of the Weather Underground in the 60s.