Earlier, Republican presidential candidate Mitt Romney blamed what he said have been President Obama's "failed" economic policies for the nation's stubbornly high unemployment rate and weak job growth.

In Minnesota this hour, President Obama conceded "we've got a lot of work to do before we get to where we need to be," but also claimed credit for policies that he said prevented another Great Depression after the financial crisis of 2008.

The board of the Leadership Conference of Women Religious (LCWR), which represents most nuns in the United States, rejected a report from the Vatican that found they were running afoul of church doctrine.

The report, which among other things expressed concerned about the group's "radical feminism," was issued in April and ruled that an American archbishop would bring the nuns back in line.

Scientists at the University of Leeds are exploring ways to use magnetic bacteria to build biocomputers of the future. Meanwhile, another group of researchers, reporting in Science, write that they have unearthed deep-sea microbe that live off nutrients from the dinosaur age.

In Ignorance: How It Drives Science, neuroscientist Stuart Firestein writes that science is often like looking for a black cat in a dark room, and there may not be a cat in the room. Firestein discusses why the hit-or-miss process, the "not knowing" is the true engine of science.

Reporting in Science, researchers write that a combination of therapies, willpower and chocolate helped rats with severe spinal cord injuries learn to walk and even run again. Neurobiologist Moses Chao, not affiliated with the study, discusses the rehab method and whether it could work in humans.

Russian President Vladimir Putin denied claims made by Secretary of State Hilary Clinton that Russia is "in effect, propping up" the regime of Syrian President Bashar Assad.

"We don't supply weapons that can be used in civil conflicts," Putin told reporters in Berlin after he met with German Chancellor Angela Merkel.

Mitt Romney gets enough delegates, in some counts, to go over the top in his bid for the GOP nomination. But his celebration gets distracted by more Donald Trump "birtherism." Plus, the Texas GOP goes into overtime to find a Senate nominee, Rep. Thad McCotter plans a write-in campaign in Michigan in hopes of keeping his own job, and a look ahead to the Wisconsin recall.

NPR's Ken Rudin and Ron Elving have the latest political news in this week's roundup.

This interview was originally broadcast on January 11, 2011.

Writer Mira Bartok was 40 years old when a semi-trailer hurled into her car on the New York Thruway. The force of the accident whipped the inside of her brain against her skull, causing what's known as coup contrecoup, a type of traumatic brain injury that for Bartok, affected both her long- and short-term memory.

On Saturday, the Susan G. Komen Global Race for the Cure will be run and walked in Washington. This year, the field won't be so crowded.