Talk of the Nation on KAZU

In parts of the southeastern US, aggressive fire ants have been driven out by an even more recent arrival, the tawny crazy ant. Edward LeBrun, a researcher at the University of Texas at Austin, describes the newcomers and how one invasive species can out-invade another.

North Carolina State University biologist Rob Dunn and colleagues surveyed people's pillow cases, refrigerators, toilet seats, TV screens and other household spots, to learn about the microbes that dwell in our homes. Among the findings, reported in the journal PLoS One, homes with dogs had more diverse bacterial communities, and higher numbers of "dog-associated" bacteria.

Smartphones, tablets and computers could help seniors stay connected to their communities and families. But a hefty price tag, steep learning curves, and designs meant for younger eyes and hands could keep some older adults from logging on. Guests discuss the best ways for seniors to tackle new technology, and how devices can be adapted to accommodate older users.

Last year scientists reported that a skin cancer drug appeared to reverse the effects of an Alzheimer's-like disease in mice. But four studies out this week in Science question the original results. Ronald Petersen, director of the Mayo Clinic's Alzheimer's Disease Research Center, talks about the new findings, and the hunt for Alzheimer's drugs.

Scientists say climate change could increase pests and weeds, lengthen growing seasons and turn dry soil to dust. Farmers are already on the offensive, adopting no-till cropping methods to conserve water and experimenting with different seeds. And scientists are using a technique called gene silencing to develop new crops--without tinkering with the plants' DNA.