Male and female Túngara frogs. Among these frogs, the guy with the best call usually wins the gal — except when you throw a third-choice loser into the mix. Alexander T. Baugh/Encyclopedia of Life hide caption

itoggle caption Alexander T. Baugh/Encyclopedia of Life

Dr. Bill Mahon says a gorgeous coast and the chance to practice a more personal style of community medicine lured him to remote Fort Bragg, Calif., 35 years ago. Farida Jhabvala Romero/KQED hide caption

itoggle caption Farida Jhabvala Romero/KQED

Male treehoppers make their abdomens thrum like tuning forks to transmit very particular vibrating signals that travel down their legs and along leaf stems to other bugs — male and female. Courtesy of Robert Oelman hide caption

itoggle caption Courtesy of Robert Oelman

Heroin sold in the U.S., like this dose confiscated in Alabama last fall, is often cut with other drugs. Tamika Moore/AL.com/Landov hide caption

itoggle caption Tamika Moore/AL.com/Landov

Ah, sugar — we love the sweetness, but not the calories. For more than a century, food technologists have been on a quest for the perfect, guilt-free substitute. The latest candidate, allulose, is not available to consumers in a crystal form: It is a syrup only available to manufacturers. Ryan Kellman/NPR hide caption

itoggle caption Ryan Kellman/NPR

An aerial view of Tokyo Electric Power Co.'s tsunami-crippled Fukushima Dai-ichi nuclear power plant, on March 11. Kyodo/Reuters/Landov hide caption

itoggle caption Kyodo/Reuters/Landov

University Medical Center New Orleans on Aug. 1, when the $1 billion facility welcomed its first patients. Brett Duke/The Times-Picayune/Landov hide caption

itoggle caption Brett Duke/The Times-Picayune/Landov

Michael Arnott, of Cambridge, Mass., says he used to have trouble staying awake on long drives. Sleep specialists discovered he has obstructive sleep apnea, though not for the most common reasons — he isn't overweight, and doesn't smoke or take sedatives. M. Scott Brauer for NPR hide caption

itoggle caption M. Scott Brauer for NPR

Frozen sperm straws and embryos are stored in liquid nitrogen, in a process known as cryopreservation. One question confronting the courts: Should embryos such as these be treated as property, or as children subject to custody action? Veronique Burger/Science Source hide caption

itoggle caption Veronique Burger/Science Source

Dwarf planet Ceres is seen in the asteroid belt between Mars and Jupiter, where it resides well away from Earth. NASA is hoping to quell online rumors that a massive near-Earth asteroid is due to hit us next month. NASA/Reuters/Landov hide caption

itoggle caption NASA/Reuters/Landov

United has purchased 15 million gallons of renewable jet fuel made from beef tallow, or fat, by Alt Air Fuels and plans to use the fuel this year for Los Angeles-to-San Francisco flights. Tony Ruppe/United hide caption

itoggle caption Tony Ruppe/United