NASA's iconic images of Earth from space date back to the late 1960s--with snapshots taken by Apollo astronauts. The modern "blue marble" images are captured by machines and they're not photos. They're datasets collected by instruments aboard satellites and then translated into imagery on the ground.

Amyloid plaques and tangles of protein in the brain are two of the key signs of the form of dementia known as Alzheimer's disease. In new work reported in the journal PLOS One, researchers tracked the spread of tangles of tau protein from neuron to neuron in the brains of mice. Study co-author Karen Duff of the Columbia University Medical Center discusses the findings.

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IRA FLATOW, HOST:

This is SCIENCE FRIDAY. I'm Ira Flatow. What grosses you out, the sight of maggots squirming on a rotten piece of meat? How about a cockroach running around your spice cabinet when you turn the lights on at night? How about eating strange organ meat like sweetbreads, pancreas. Maybe just a doorknob is enough to give you the chills, touched by so many hands, or a toilet seat touched by - well, you know, there must be so many germs, right.

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RENEE MONTAGNE, HOST:

NPR's Business News starts with a reversal from the Komen Foundation. The Susan G. Komen For The Cure Foundation has just announced that it will not pull its funding for Planned Parenthood after all. The breast cancer charity endured a massive backlash when it announced, earlier this week, it would no longer give Planned Parenthood money for breast cancer screening. NPR's Julie Rovner joins us to explain the turnaround. And Julie, what exactly did the Komen Foundation say this morning?

Saying officials have undertaken yet another campaign of "bullying and harassment" of its Persian service staff, the BBC called on the Iranian government to "repudiate the action of its officials."

In a blog post, the BBC's Director General Mark Thompson also called on the international community to "put maximum pressure on Iran to desist in this campaign of intimidation, persistent censorship and a disturbing abuse of power."

The Labor Department said the economy added 243,000 jobs in January, well beyond many economists' expectations. The unemployment rate fell to 8.3 percent.

Human Rights Watch has a harrowing report out today about what it says is the targeting of children by Syria's government forces.

"Children have not been spared the horror of Syria's crackdown," Lois Whitman, children's rights director at Human Rights Watch, said in a statement. "Syrian security forces have killed, arrested and tortured children in their homes, their schools or on the streets. In many cases, security forces have targeted children just as they have targeted adults."

Nevada has the lowest high school graduation rate in the country. But now a multi-million dollar federal grant is helping one district turn its schools around. Host Michel Martin speaks with a principal who spent last Saturday knocking on the doors of students who dropped out, encouraging them to come back to school.

The brutal recession has wracked Nevada, where soaring unemployment and foreclosure numbers tell the story of the state's misery. But its importance as a swing state in the 2012 presidential contest has only been enhanced in the four years since it went for Democrat Barack Obama.

After days of controversy, the Susan G. Komen for the Cure foundation has said it will reinstate funding for Planned Parenthood.

Earlier this week, the foundation moved to discontinue funding of breast cancer screening by Planned Parenthood. The Associated Press reported the change came because of a new Komen policy forbidding grants to organizations under official investigation.