struggles would transform the world during the twentieth century. Instead, it turned out to be the age of ethnonationalist conflicts. Wars fought in the name of national liberation or ethnic autonomy comprise only one fifth of the wars between the Congress of Vienna (1814) and the Treaty of Versailles (1919). From Versailles to 2001, however, the share of ethnonationalist wars rose to 45 percen...

The literature on civil wars is extensive and growing. Past studies have focused on a series of questions, most notably: what are the causes of civil wars, why do some conflicts last longer than others, what causes civil wars to end, and finally why do some civil wars recur, at times repeatedly? In answering these questions, previous studies have treated each of these problems as discrete and i...

survival such as GVHD and leukemia risk group. Elmaagacli and colleagues propose several explanations for these results (see figure). First, myeloid cells are a reservoir for CMV. It is possible that viral reactivation in AML blasts makes them a target for subsequent attack by virus-specific cytotoxic T cells (CTLs). Alternatively, CMV reactivation in AML cells may up-regulate leukocyte fixatio...

In October 2014, an Antares rocket blasted off from a NASA launch pad on one of Virginia’s barrier islands, and exploded seconds later. In addition to about 5,000 pounds of food and equipment destined for the International Space Station, the doomed rocket was carrying 26 miniature satellites called CubeSats, one of which housed physicist Alexander Ling’s experiment. “We thought, ‘oh, that’s it,...