Coursera founders Andrew Ng and Daphne Koller are computer science professors at Stanford University. Jeff Chiu/AP hide caption

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Vice President Richard Nixon listens as Sen. John F. Kennedy talks during their televised presidential race debate. This photo was made from a television screen in New York, Oct. 21, 1960. AP hide caption

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President Obama speaks during a campaign event at University of Colorado Boulder Sept. 2. He and his Republican challenger, Mitt Romney, will have their first debate at the University of Denver on Wednesday. Pablo Martinez Monsivais/AP hide caption

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Supporters of opposition presidential candidate Henrique Capriles attend a campaign rally in Valencia, Venezuela, on Thursday. Capriles is running against President Hugo Chavez in the country's Oct. 7 election. Rodrigo Abd/AP hide caption

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Mohammed Naeem, a driver, holds up a framed photo of two relatives he says were killed by militant leader Abdullah near the western city of Herat. Soraya Sarhaddi Nelson/NPR hide caption

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President Barack Obama and Republican presidential candidate Mitt Romney both campaigned in the battleground state of Ohio this week. AP hide caption

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Lorie Miller affixes a QR code to her grandparents' gravestone. Miller and her husband are launching a business that will supply QR tags and maintain a website featuring the deceased. Emma Lee/Newsworks hide caption

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Archbishop John J. Myers stands outside Cathedral Basilica of the Sacred Heart in Newark, N.J. The archbishop has urged followers to assess the presidential candidates for their views on abortion and gay marriage. Mel Evans/AP hide caption

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British Cabinet Minister Andrew Mitchell is accused of denigrating a police officer during an altercation over his bicycle. Dan Kitwood/Getty Images Europe hide caption

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New York Times publisher Arthur Ochs Sulzberger in his office in 1973. Anthony Camerano/AP hide caption

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James Hoffa was last seen in the parking lot of a Detroit restaurant in 1975 CT/AP hide caption

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