Snippets From Science

America’s favorite seafood is…you guessed it…shrimp. If it’s one of your favorites, too, better not read on. The U.S. is the world’s largest importer of shrimp, and most of them are now raised under crowded conditions in coastal ponds in far-away lands. Thailand, India, Indonesia, China, Vietnam, Bangladesh, and Guyana now provide most of our restaurant shrimp. Ponds in which they are raised are often treated with antibiotics (such as chloramphenicol), steroids, and/or pesticides. Mortality rates are often 30 percent or more, and in some cases an entire population is lost to virus disease. In 2007, the FDA examined 87 samples of shrimp from China and found that 25 percent of them tested positive for drug residues. One of these days we may be able to specify that we want only domestic, wild-caught shrimp. For now, don’t perch and whitefish sound pretty good? For more info, Google “shrimp farming.”

• Recent studies by atmospheric scientists conclude that skies “…became dimmer over most land areas between 1973 and 2007.” This is contrary to earlier reports that argued for global “brightening.” It appears that aerosols (e.g., soot, dust, fine sand) are the major culprits in global dimming. They reduce solar radiation on the planet’s surface, with energy lost either through upward reflection or through heating the atmosphere. Cloud formation may also be affected. The only part of the globe where visibility increased was over Europe, probably due to regulations limiting sulfur release from power plants. The bottom line is that whether skies are dimming or brightening, either trend will affect life on the planet. (Science, March 13, 2009)

• One of the hot areas in neuroscience these days involves the existence of “mirror neurons” in primates and humans. Giacomo Rizzolatti, at the University of Parma in Italy, implanted electrodes in the brains of two monkeys. One monkey, named Carlos, ate a peanut while the other, named Guido, watched. Scientists monitored which neurons were involved as Carlos examined the peanut and then ate it, and they simultaneously monitored the neurons firing in Guido’s brain. To everyone’s surprise, exactly the same neurons fired in Guido’s brain, as a passive observer, as in Carlos’ brain. Since this discovery, such mirror neurons have been confirmed over and over again in both monkeys and humans. Apparently, what happens when we watch someone kick a ball, brush their teeth, or give us a bright smile, is that mirror neurons in our brain simulate the action. Some scientists theorize that mirror neurons play a substantial role in helping to develop social and emotional habits in childhood. A growing number of behaviorists believe they may even play a role in autism, since some studies have shown that there are fewer mirror neurons in autistic children. Can I feel your pain? If mirror neurons are involved, the answer is yes.

•Afraid of snakes? Be thankful you didn’t live about 60 million years ago. Recently, archaeologists discovered the fossilized remains of a relative of the boa constrictor in northeastern Columbia (Nature, Feb. 5, 2009). They estimated that it was about 41 feet long and probably fed on crocodiles – and anything else within reach. Named Titanoboa cerrejonensis, it probably weighed a ton or more.