U.S. billionaire David Koch has died at age 79

WASHINGTON -- Billionaire industrialist David H. Koch, who with his older brother, Charles, transformed American politics by pouring their riches into conservative causes, has died at age 79. Charles Koch announced the death on Friday, saying, "It is with a heavy heart that I now must inform you of David's death." David Koch, who lived in New York City, was the Libertarian Party's vice-presidential candidate in 1980. He was a generous donor to conservative political causes as well as educational