12 ноября 2002 г.
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Новости науки и техники в "Scientific American"
12 ноября 2002 г. |
GLOBAL ESTIMATE OF ENDANGERED PLANT SPECIES TRIPLESThe number of plant species threatened with extinction may be more than three times higher than previously thought, researchers report. Current estimates put 13 percent of global flora at risk of extinction. But this number does not include a reliable count of plants from tropical regions, where the majority of the world's plants grow. Based on the results of a new study, scientists conclude that as many as 47 percent of the world's plants are endangered.MAKING MICROCHIPS TAKES MOUNTAIN OF MATERIALSThe growing popularity of microchips, currently found in applications ranging from cellular phones to cars, illustrates their increasing affordability. But a new report indicates that the environmental costs associated with producing the small silicon chips are much bigger than their size might suggest. The manufacturing of a typical two-gram chip, scientists say, takes 1.6 kilograms of fossil fuel, 72 grams of chemicals and 32 kilograms of water.BOOK OF THE MONTH: ROSALIND FRANKLIN: THE DARK LADY OF DNA By Brenda MaddoxThe aphorism "history is always written by the victors" is as true for science as for geopolitics. Certainly it was the case for the discovery in 1953 of the double helical structure of DNA, the most important discovery in 20th-century biology. The victors were James Watson and Francis Crick, who together with Maurice Wilkins shared the 1962 Nobel Prize for crossing the finish line first. The loser was Rosalind Franklin, who produced the x-ray data that most strongly supported the structure but was not properly acknowledged for her contributions.THE SA 50 AWARDScientific American is pleased to honor 50 individuals, teams, companies and other organizations. Through their many accomplishments in 2001-2002, they have demonstrated clear, progressive views of what our technological future could be, as well as the leadership, knowledge and expertise essential to realizing those visions. Congratulations.STAR 'HEARTBEATS' HELP STIR UP GALAXIESComputer simulations may help astronomers better explain the slow pace of star formation. Periodic heating of interstellar gas by ultraviolet radiation, it seems, could keep the gas agitated enough to prevent its condensation into stars.WILDFIRES FACTOR SIGNIFICANTLY IN GLOBAL CARBON BALANCEWildfires dominated the western parts of the United States earlier this year and established 2002 as the most expensive fire year yet. But the consequences of burning land and brush are more than just financially costly. New study results suggest that wildfires can have a huge impact on the amount of greenhouse gases, particularly carbon dioxide, in the atmosphere. Specifically, scientists found that fires in Indonesia during 1997 spewed the same amount of carbon into the air as is typically removed annually by the entire planet's biosphere.ASK THE EXPERTS: DO SCENTS AFFECT PEOPLE'S MOODS OR WORK PERFORMANCE?Rachel S. Herz, an assistant professor of psychology at Brown University, provides the following explanation.