Barbadian singer Rihanna has bounced back from an altercation with ex-boyfriend Chris Brown, and has landed four nominations for the 2009 Urban Music Awards. Rihanna, 21, is up for the top categories of Best Female Act, Best R&B Act, and Artist of the Year, reports Contactmusic. And her “Rehab” music video, which features Justin Timberlake, is among the nominees for Best Music Video. Amy Winehouse, Estelle, M.I.A. and Keri Hilson will challenge her for the Best Female crown. The awards, voted for by fans online, will be handed out on Jul. 17 in New York City.