National

University of New Hampshire professor Yitang Zhang announced this week that he has come close to solving a centuries-old problem: proving the twin prime conjecture. Host Scott Simon gets an explanation from Weekend Edition Math Guy Keith Devlin of Stanford University.

It's been a long slog already for the bipartisan immigration overhaul proposed by the Senate's Gang of Eight.

The legislation has been the target of more than 300 amendments during days of debate and votes by the Senate Judiciary Committee. But while the bill has largely held its own so far, its prospects for getting through Congress remain uncertain.

In Judiciary Committee Chairman Patrick Leahy's view, the immigration overhaul is "moving very well."

"It's moving a lot faster than people said it would," says Leahy, a Vermont Democrat.

When the American Psychiatric Association releases its new Diagnostic and Statistical Manual of Mental Disorders -- DSM-5 -- this weekend, lots of journalists and commentators will refer to it as "psychiatry's bible."

That's a term that makes the manual's authors and other mental experts cringe.

The Portland Thorns women's soccer team drew 17,000 screaming fans to its recent home opener. That's a huge number and one that dwarfed turnout for the other seven teams in the new National Women's Soccer League (NWSL). The NWSL is the latest attempt to bring sustainable women's pro soccer to the U.S. Soccer federations in the U.S., Mexico and Canada help fund it. NPR's Tom Goldman examines how the Thorns and the NWSL have done so far.

An unsolved triple murder in the Boston suburbs is getting a closer look in the wake of the marathon bombings. One of the victims may have been a friend of bombing suspect Tamerlan Tsarnaev. That's prompting authorities to revisit the 2011 case.

The murders took place in Waltham, Mass. On Sept. 12, 2011, police responded to a house in the leafy suburb a few miles west of Boston.

The House Ways and Means Committee became the first oversight panel in Congress to weigh in on the IRS tax-exempt group controversy on Friday morning.

President Obama's first term was free from the kind of scandal that consumes every ounce of political oxygen in Washington. Now, in light of a trio of controversies, his supporters find themselves in the uncomfortable and unaccustomed position of having to defend some hard-to-defend events.

Democrats have offered up a range of responses. They view the issues — Benghazi, the IRS and the Justice Department snooping on The Associated Press — as separate issues that shouldn't be lumped together.

The Illinois Senate has approved a measure to legalize the use of marijuana for medical purposes, sending the bill to the governor for his signature.

The bill would be the strictest in the nation. According to The Chicago Tribune: