Originally created 08/07/03


Feeling jumpy

A garden pest known as the froghopper has vaulted over the flea to claim the title of champion jumper.

Scientists have considered fleas, which can exert a force 135 times that of their body weight, to be the most powerful jumpers. But in the latest issue of the journal Nature, Malcolm Burrows of the University of Cambridge in England says the froghopper deserves the gold medal.

The froghopper, also known as a spittlebug, feeds on plants. The females lay their eggs in plant stems and protect them with a foamy spitlike substance. The insects seldom fly and instead leap from plant to plant.

In the new report, Mr. Burrows showed that froghoppers can exert a force that is 414 times their body weight. This force can lift the tiny insect more than 27 inches. For comparison, people exert a force only two to three times their weight.

Hungry for more

The smoke surrounding how the body regulates hunger is clearing. Endocannabinoids, molecules that are similar to the active component of marijuana, attach to proteins on brain cells that play a role in appetite, a new study shows.

Endocannabinoids occur naturally in animals and have been found in parts of the brain known for controlling appetite. A strain of mice that couldn't make the endocannabinoid-binding proteins had leaner bodies and ate less, scientists reported last week in the Journal of Clinical Investigation.

Fat cells also had the binding proteins, suggesting that the proteins play a role in breaking down fat, reported the researchers from Germany and Italy.

If drugs could be designed to block the binding proteins, they might help moderate diet and hunger, the study suggests.

Waste reduction

Chemists have discovered a catalyst that starts a chemical reaction and keeps it going, then precipitates out conveniently at the end. Scientists have long struggled to make such a substance, which could drastically cut back on the waste produced by chemical manufacturing. In last week's Nature, researchers at Brookhaven National Laboratory on Long Island describe a recyclable catalyst containing the metal tungsten.

The catalyst triggers a set of chemical reactions called hydrosilylation reactions, which are used to make drugs, pesticides and other organic compounds. After the reaction takes place, the catalyst settles out as a sticky solid that can be used again.

Still smoking

On average, teenagers see actors smoking about 1,200 times in popular movies, increasing the likelihood of adolescents taking up the habit, concludes a new study of pupils. However, parents can limit such exposure to smoking by not allowing their adolescent children to watch R-rated films, concludes Dr. James D. Sargent, the study's lead author, and his colleagues at Dartmouth Medical School in New Hampshire and the Department of Psychological and Brain Sciences at Dartmouth College.

Previous studies have indicated that teens are easily influenced to smoke if they see that behavior in movies. Two studies even suggested that adolescents were more likely to smoke if their favorite movie stars were shown smoking.

The new study surveyed 4,910 students, ages 9 to 15, on whether they had seen any of 50 well-known films in which actors are shown smoking.

On average, the adolescents had seen 30 percent of the movies and were exposed to 1,160 smoking scenes.

However, parents could cut that exposure by half if they forbade the watching of R-rated movies, the researchers said.

"Teaching parents to monitor and enforce movie access guidelines could reduce adolescent smoking in an indirect, yet powerful, manner," the researchers wrote in the Archives of Pediatric Adolescent Medicine.


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