The Oakland A's Bartolo Colon becomes the second player in a week to fail a doping test.

Major League Baseball said Colon is suspended 50 games because he tested positive for elevated levels of testosterone. It was the same thing that got the Giants' Melky Cabrera suspended last week.

It didn't go far, but the NASA rover Curiosity has taken its first test drive on Mars.

"This is how I roll," NASA writes (speaking for Curiosity) with a photo it has released showing the rover's first tracks. "Forward 3 meters, 90 [degree] turn, then back. Electric slide, anyone?"

"We have a fully functioning mobility system," NASA engineer Matt Heverly just told reporters. He said Curiosity ended up moving about 4 1/2 meters during today's test. It also did a full revolution going forward, backed up and did another revolution.

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NEAL CONAN, HOST:

This weekend, a court in Moscow sentenced three women from a previously obscure punk band guilty of hooliganism. They got two years in prison and made Pussy Riot an international sensation. In the Washington Post today, columnist Anne Applebaum writes that for all the attention paid to the case, Madonna's was by far the most damaging, not because she's a serious political figure, but because she isn't.

Each year, some 2,000 heart transplants are performed in the U.S., and the number of people on the waiting list is even larger. Between finding the perfect donor to worrying about insurance, the wait can be grueling, but heart transplant social workers are here to help.

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NEAL CONAN, HOST:

This is TALK OF THE NATION. I'm Neal Conan in Washington. Parts of the country have suffered from record heat and drought for several years in a row now, and this summer, it's been just brutal. In past programs, we talked with farmers about their crops. Today, we focus on difficult choices facing ranchers and dairy farmers.

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NEAL CONAN, HOST:

This is TALK OF THE NATION. I'm Neal Conan, in Washington. A congressman skinny dips in holy water and still can't buy a headline because another congressman redefines rape and biology, defies his own party and stands up Piers Morgan. It's Wednesday and time for a...

PIERS MORGAN: Gutless little twerp...

CONAN: Edition of the Political Junkie.

(SOUNDBITE OF POLITICAL JUNKIE INTRO)

PRESIDENT RONALD REAGAN: There you go again.

There's growing evidence that the bacteria in our gut influence our health, including how much we weigh. So what happens when antibiotics knock out some of the microbes that help us?

A study, published online today in the journal Nature, finds that antibiotics make young mice fatter by changing the mix of their gut bacteria.