Warren Buffett gained more wealth than any other U.S. billionaire, adding $37 million a day, according to one study.

Through Dec. 11, Buffett's net worth—at least on paper—shot up by $12.7 billion to $59.1 billion in 2013 from $46.4 billion at the start of the year, according to Wealth-X, the wealth research firm. That works out to a paper gain of $1.5 million an hour.

Applications are invited for joint interdisciplinary doctoral program “Human Rights under Pressure – Ethics, Law, and Politics” (HR-UP) at the Free University of Berlin and the Hebrew University of Jerusalem. HR-UP will offer 14 doctoral fellowships (7 in Berlin and 7 in Jerusalem) for its upcoming 2014 intake. Each doctoral fellowship includes a monthly stipend of €1,365, plus €103 for material expenses and mobility funds and is awarded for a period of maximum 36 month.

The final deadline for applications is January 27, 2014.