In preparing for her first film role as a petite, hard-laboring slave in '12 Years a Slave,' actress Lupita Nyong'o sized herself up against 500 pounds of cotton, which her character Patsey picked every day. Conveying that loftiness proved to be a key to Nyong'o's performance, one that has generated critical acclaim for the Hollywood newcomer and predictions she will earn a best supporting actress Oscar nomination.