Jon Hamilton

Two days before hundreds of deadly tornadoes swept through the South on April 27 and 28, meteorologists were telling people in that part of the country to get ready for powerful twisters.

But those same meteorologists have no idea whether there will be a similar outbreak of tornadoes next week or next month.

"This could be it for the rest of the season or it could continue to be crazy — we absolutely don't know," says Howard Bluestein, a professor of meteorology at the University of Oklahoma.

Pediatricians can use a five-minute questionnaire to identify many 1-year-olds with autism, according to a new study in Journal of Pediatrics.

But the screening test also flags a whole lot of babies who aren't autistic.

Researchers have found evidence that the placenta plays an important role in fetal brain development during the early stages of pregnancy.

Experiments in mice show that during a key period, the placenta becomes a source of the chemical serotonin, which helps determine the wiring of key circuits in the brain.

The finding, published in the journal Nature, could help explain what leads to brain disorders such as autism and schizophrenia. And it shows that the placenta does a lot more than simply transport nutrients from a mother to her unborn baby.

The earthquake that struck Japan on March 11 will be remembered primarily for the devastating tsunami it created. The quake itself did remarkably little damage to buildings in most areas, thanks to strict construction codes. But in a few places, particularly around Tokyo, buildings didn't fare as well.

These are places built on land reclaimed from the sea. When the earthquake struck, the soil in these areas acted like a liquid, a phenomenon known as liquefaction.

NPR's Jon Hamilton reports on the latest developments relating to Japan's damaged nuclear power complex.