Just about every year, Halloween features parties at which some students dress in ways that cause offense, typically over issues of race and ethnicity. Northwestern University, which last year saw a controversy over the blackface costumes of a few students, is trying to prevent such incidents this year. The Chicago Tribune reported that Burgwell Howard, the dean of students, sent an e-mail to all students Monday urging them to avoid racially insensitive costumes. He specifically discouraged "ghetto," "pimps and hos" and "gangsta" parties. "Halloween is unfortunately a time when the normal thoughtfulness and sensitivity of most NU students can be forgotten and some poor decisions are made," Howard wrote.