The U.S. intelligence community believes that North Korea tested a nuclear device last month with an explosive yield of several kilotons, considerably more powerful than its first test nearly three years ago.
Juan Martin del Potro shocked world number one Rafael Nadal in the quarterfinals of the Sony Ericsson Open Thursday. The Argentine, who is seeded sixth in Miami, defeated the top seed 6-4, 3-6, 7-6 (7/3), in front of a raucous, pro-del Potro crowd.