Billionaires Carlos Slim And Bill Gates Announcement On Funding The CIMMYT Agricultural Initiative [Getty Images]

Billionaires Bill Gates, back left, and Carlos Slim wait for the start of a news conference to announce donations to Mexico's International Maize and Wheat Improvement Center, known by its Spanish initials as CIMMYT, in Texcoco, Mexico, on Wednesday, Feb. 13, 2013. The group, which performs research for agricultural productivity, opens its research facility this week. Photographer: Susana Gonzalez/Bloomberg via Getty Images

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