National and World News from NPR

Any dog owner will tell you that they're a lot less stressed out when they're with their dog. Even at work. And now science agrees.

People who took their dogs to work in an office in Greensboro, N.C., had lower stress levels through the work day, as reported on self-reported test.

The employees who hadn't brought their dogs to work said their stress levels increased through the work day. So did the non-pet owners. But the dog owners said they stayed mellow as the day went on.

MasterCard and Visa have warned banks that a third party processor has experienced a data breach. In statement, both card associations acknowledged the breach and MasterCard said that law enforcement is involved and "is currently the subject of an ongoing forensic review by an independent data security organization."

Want to hear a joke about sodium hypobromite? NaBrO! Can science be the butt of a good joke? Ira Flatow and guests test the hypothesis in an annual April Fools' joke-a-thon. They share the best gags in the business. Sidesplitting or groan-worthy? You decide.

This mystery has plagued arachnologists for decades. William Eberhard and Daniel Briceno untangle the web question in a paper in the journal Naturwissenschaften. The answer has to do with spiders' oily, hairy legs.

In The Age of Insight: The Quest to Understand the Unconscious in Art, Mind and Brain, Nobel Prize-winning neuroscientist Eric Kandel writes of turn-of-the-century Vienna, where artists mingled with writers, scientists and physicians, and explains how the brain perceives a work of art.

The film director James Cameron has just completed a dive to Challenger Deep, the deepest point on Earth at nearly 36,000 feet under the sea. His manned descent is the first in 52 years, since the oceanographers Don Walsh and Jacques Piccard explored the Mariana Trench in the bathyscaphe Trieste.

With $540 million (wait — it just went up to $640 million!) on the line, it's not surprising that Alabama resident Lance Larka is willing to drive across the state line for a chance to win the record Mega Millions jackpot.