Katrina laid bare America's class divide, as better-off residents escaped New Orleans while poor blacks suffered in the city's stinking Superdome.

ECONOMIST: Seeking a cure for the hurricane hangover | The

Like a key in a lock, EGF binds to a receptor on a cell's surface, sending off a signal to the cell to divide, grow and die.

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There is a great divide in business schools, and one that not many outsiders are aware off.

FORBES: Business schools suffer from a dangerous lack of evidence based teaching

"If you can't even retain a lawyer and you have nothing to divide up except for debt, then I think you're better off to wait, " she said.

CNN: Economy prolongs some marriages, ends others

Mr Obama's relentless courting of middle-of-the road voters also paid off, providing him with some evidence that he has succeeded in crossing the red-blue divide.

ECONOMIST: The presidency