Health & Science
What the hammerhead sees; An autism treatment that works; Another benefit of wine; Snowflakes shaped like triangles
What the hammerhead seesWith its T-shaped head and wide-set eyes, the hammerhead shark surely ranks among the strangest-looking creatures in nature. But its bizarre appearance has a purpose, researchers now report, giving it an unparalleled view in nearly every direction. Biologists at Florida Atlantic University put captive hammerheads in a tank, implanted electrodes in their eyes, and then flashed a light in various locations to measure what each eye saw. The sharks demonstrated superb stereoscopic vision, with a nearly 360 degree field of view: It can see above, below, and behind simultaneously. Its only blind spot is a large area directly in front, which it overcomes by swinging its head from side to side as it swims. Anecdotally, divers have reported seeing “little fish schooling right in front of the hammerheads’ heads,” study leader Michelle McComb tells National Geographic News. “It’s like the fish are swimming by and saying, ‘Ha, ha, ha, you can’t see me!’”
An autism treatment that worksParents of very young children diagnosed with autism at last have some reason for hope. In the first randomized controlled study of its type, researchers have found that when autistic toddlers participate in a specialized therapy program, their IQs and social and language skills improve significantly. Autism, which may affect as many as one in 100 children in the U.S., is a neurological disorder marked by repetitive behaviors and impaired social and verbal skills. In recent years parents and doctors have been urged to screen children younger than 18 months for signs of autism, with little to offer in the way of intervention. “Now we know we have methods that are effective,” study co-author Geraldine Dawson tells CNN.com. In the study, autistic children 18- to 30-months old were enrolled in a program using the Early Start Denver Model, an intervention method in which a therapist and parents stimulate the kids through play-oriented learning games. After two years, the ESDM group scored higher on skills for listening, self-care, and motor tasks, and their average IQ had risen nearly 18 points. Some of the children no longer were diagnosed as autistic, although some of their problems remained. “The cost of providing this treatment when the child is very young is way less” than the subsequent cost of adult care, says psychologist Laura Schreibman. “There is a treatment we know is effective. Let’s get on with it.”
Another benefit of wine Fresh out of toothpaste? Try a Cabernet, or maybe a Beaujolais Nouveau. Researchers in Italy have found that in addition to its other health benefits, red wine can help prevent tooth decay. It’s not just the alcohol that does the trick, although that also is known to kill Streptococcus mutans, the bacterium mainly responsible for cavities. To see if wine had other ingredients that inhibited cavities, researchers worked with wine from which the alcohol had been removed. In the lab, they cultured the cavity-causing bacteria on extracted teeth and ceramic beads, and when the nonalcoholic wine was added, the bacteria failed to hold on. The secret ingredient turns out to be proanthocyanidins, a class of compounds found in various vegetables and fruits, including grapes. It’s unclear whether grape juice alone can fight cavities, since “grape juice and wine have very different chemical compositions,” food chemist and study author Gabriella Gazzani tells Discovery News. But if the proanthocyanidins could be separated out from wine’s acids and sugars, which can cause cavities, Gazzani says the compounds might one day arrive directly from your toothbrush.
Snowflakes shaped like trianglesTextbooks teach that snowflakes have six sides. Yet the snowflake literature is thick with sightings of triangular ones. “People have noticed them for hundreds of years,” physicist and snowflake enthusiast Kenneth Libbrecht tells Science News. The cause of the triangular shape, Libbrecht and a colleague found recently, is aerodynamics. In their lab, the scientists created a machine that permits snow crystals to grow and fall in conditions similar to nature. In a recent test, they noted that small perturbations—a speck of dust—on a falling crystal can sometimes tilt one edge of the flake downward. This changes the air flow around it, increases the growth rate on the downward side, and induces “a morphology that becomes more triangular with time,” Libbrecht says. The pattern is stable: Unlike hexagonal crystals, which continue to change in shape as they fall, triangular flakes tend to stay triangular.