Новости науки и техники в "Scientific American"

STUDY SUGGESTS MARIJUANA ABUSE INCREASES RISK OF DEPRESSION

Its proponents argue that smoking marijuana makes you feel better. But according to a study published in the December issue of the American Journal of Psychiatry, adults who abuse the drug may be at greater risk for depression. The findings, the researchers say, "underscore the importance of cannabis abuse prevention rather than treatment."

SATELLITES HELP SCIENTISTS MAP GLOBAL LIGHTNING PATTERNS

We may not know when lightning is going to strike, but scientists now have a much better picture of where it has struck in the past. NASA scientists recently announced that they have compiled the best map yet of lightning strikes. "For the first time, we've been able to map the global distribution of lightning, noting its variation as a function of latitude, longitude and time of year," Hugh Christian, leader of the National Space Science and Technology Center's lightning team says.

NATURAL VIRAL ENZYMES DO BATTLE AGAINST DRUG-RESISTANT BACTERIA

Increasingly many bacteria are becoming resistant to antibiotic treatment, presenting a serious public health threat. But new research reveals that these bacteria are often still vulnerable to a natural enemy from within--namely an enzyme manufactured by viruses, or bacteriophages, found inside the organisms.

THE SIBLEY GUIDE TO BIRD LIFE & BEHAVIOR

Illustrated by David Allen Sibley. Edited by Chris Elphick, John B. Dunning, Jr., and David Allen Sibley. Alfred A. Knopf One year after publication of the widely praised SIBLEY GUIDE TO BIRDS comes this companion volume, which tells how birds live and what they do. Readers will learn about feathers, feet and flight dynamics; food, foraging and courtship; breeding, migration and conservation threats.

NEW DATA KICKS UP 'SNOWBALL EARTH' FIGHT

In 1998, two Harvard scientists put forth a chilling description of earth's climate some 650 million years ago. Their theory, dubbed snowball earth, held that between 750 million and 580 million years ago, ice repeatedly enveloped our planet, coating the seas from pole to pole and killing off early life almost completely. During the past few years, the idea has stirred up a great deal of debate. And new data only further throws snowball earth into question.

BIOLOGISTS DISCOVER WORLD'S SMALLEST LIZARD

When Pennsylvania State University evolutionary biologist Blair Hedges is rooting around in dead leaves on his hands and knees, hunting for the tiniest animals alive, he grabs for any flash of movement he sees. Most recently, his labors earned him a dime-size Caribbean gecko--the world's smallest creature among reptiles, birds and mammals.

ASK THE EXPERTS: HOW DO NEON LIGHTS WORK?

Eric Schiff, chair of the physics department at Syracuse University, provides a response.