COLUMBUS (AP) — A tenured Ohio State professor has resigned after a review alleged he improperly accepted up to $200,000 for speaking engagements across the country. The Columbus Dispatch reports Terrell Strayhorn left the College of Education and Human Ecology in May after being fired two months earlier as director of the university’s Center for Higher Education Enterprise and placed on indefinite unpaid leave. Strayhorn has said the payments were proper and any violations resulted from “a lack of clear guidelines” by the university.