EMERGING MARKETS-Mexican peso slips ahead of NAFTA trade talks

By Bruno Federowski SAO PAULO, Nov 13 (Reuters) - The Mexican peso slipped on Monday ahead of the latest round of trade negotiations between Mexico, the United States and Canada later this week. Concerns that U.S. President Donald Trump could make good on his threats to scrap the North American Free Trade Agreement (NAFTA) have battered the Mexican currency in recent weeks. Trump has put forward increasingly strict demands in the negotiations. "The market is no longer optimistic