The National Weather Service issued an initial finding that the tornado was an EF-4 on the enhanced Fujita scale, the second most powerful type of twister.

NPR: Medical Examiner: 24 Dead In Oklahoma Twister

Initial trial results for Avastin in colon and kidney cancer were promising, prompting Genentech to start large-scale tests.

FORBES: On The Cover/Top Stories

In negotiations held in March between Steven Rattner, the investment banker who leads the task-force, and Sergio Marchionne, Fiat's boss, Fiat agreed to scale back its initial stake to 20% and not to increase it beyond 49% until Chrysler had repaid American taxpayers in full.

ECONOMIST: America's car industry

The survey of 4, 000 current customers measured satisfaction with call quality, company image, account management, initial activation, service plan options, and customer service, with Virgin scoring 751 on a 1, 000-point scale.

ENGADGET: Virgin Mobile takes top prepaid honors in J.D. Powers survey