David Brown

A team of researchers has come up with a list of two dozen "ultraconserved words" that have survived 150 centuries. It includes some predictable entries: "mother," "not," "what," "to hear" and "man." It also contains surprises: "to flow," "ashes" and "worm."

For U.S. men and women who have fought in Iraq and Afghanistan, death behind the wheel is becoming another lethal aftereffect of combat. Veterans of the two wars have a 75 percent higher rate of fatal motor vehicle accidents than do civilians.

You know that dog biscuit shaped like a bone but made mostly of wheat? The fact that your dog is satisfied with it instead of going for a piece of your thigh may be one of the big reasons why its ancestors evolved from wolves to house pets.

Post-traumatic stress disorder and traumatic brain injury can increase a person's anger and hostility and diminish his or her self-control. But the link between those disorders and outright violent behavior is weak and hard to pin down with certainty.