International Commission Forges Ahead To Identify Genocide Victims By Sally
EXHUMATION begins the DNA forensic process. Officials from the International Commission on Missing Persons, including Queen Noor of Jordan fourth from left , oversee this June 2003 disinterment of a mass grave outside Sarajevo. EXHUMATION begins the DNA forensic process. Officials from the International Commission on Missing Persons, including Queen Noor of Jordan fourth from left , oversee this June 2003 disinterment of a mass grave outside Sarajevo. Tuzla, Bosnia-Herzegovina Forensic...
ThlNuclear
A threefold expansion of nuclear power could contribute significantly to staving off climate change by avoiding one billion to two billion tons of carbon emissions annually BY JOHN M. DEUTCH AND ERNEST J. MONIZ Nuclear power supplies a sixth of the world's electricity. Along with hydropower which supplies slightly more than a sixth , it is the major source of carbon-free energy today. The technology suffered growing pains, seared into the public's mind by the Chernobyl and Three Mile Island...
An Advanced Turbine Design For Versatile Missiles By Steven Ashley
Suppose that U.S. intelligence finds indisputable evidence that a major terrorist leader is dining right now in a remote farmhouse in central Asia. Say also that local political sensitivities prohibit calling in bombers for an air strike and that the meal is unlikely to last the two hours it would take a Tomahawk cruise missile to reach the site from its maximum range. How to respond Pentagon weapons procurers hope to have an answer in an advanced turbine engine that can shrink a cruise...
Pregnant With Implications
Cesarean sections declined in the seven years following 1989, when U.S. birth certificates first recorded methods of delivery. But recently they have spiked. Proposed explanations include an increase in multiple births and in the number of women more likely to have a C-section, such as those who are older, overweight or diabetic. Brie Finegold Percent of births delivered by cesarean section in 2004 29.1 1996 20.7 1989 22.8 Percent increase in twin births, 1990 to 2003 37.1 Fraction of women in...
Ask The Experts
What do butterflies do when it rains Michael Raupp, professor of entomology at the University of Maryland, enlightens. Subscribe to Scientific American Digital 13-year archive with more than 150 issues Visit www.sciamdigital.com THE MAY ISSUE underscored the maxim that scientific research typically raises more questions than it answers. For instance, in the cover story The First Few Microseconds, Michael Riordan and William A. Zajc described collider experiments that slammed gold nuclei...
I Energy Efficiency
Uses 50 percent less energy than a conventional office building Natural ventilation and lighting systems External louvers provide shade on hot sides of building Unshielded windows on cool sides improve natural light Long, narrow structure minimizes solar heat Naturally ventilated stairwells Open floor plan and operable windows harness breeze Uses 50 percent less energy than a conventional office building Natural ventilation and lighting systems External louvers provide shade on hot sides of...
By Jeffrey D Sachs
Encouraging lower fertility in the developing world will pay off for everyone. How do batteries store and discharge electricity Does damp weather make arthritis pain worse Cover image by Phil Saunders, Space Channel Ltd. photograph at left by Honda Motor Company. Scientific American ISSN 0036-8733 , published monthly by Scientific American, Inc., 415 Madison Avenue, New York, N.Y. 10017-1111. Copyright 2006 by Scientific American, Inc. All rights reserved. No part of this issue may be...
SCIENTIFIC AMERICAN Wws
carbonizing by turning back to coal. About 850 coal-fired power plants are slated to be built by the U.S., China and India none of which signed the Kyoto Protocol, Hoffert says. By 2012 the emissions of those plants will overwhelm Kyoto reductions by a factor of five. Even if plan A works and the teenagers of today complete the first leg of the relay by the time they retire, the race will be but half won. The baton will then pass in 2056 to a new generation for the next and possibly harder part...
Stirling Engine
A high-performance Stirling engine shuttles a working fluid, such as hydrogen gas, between two chambers a . The cold chamber blue is separated from the hot chamber orange by a regenerator that maintains the temperature difference between them. Solar energy from the receiver heats the gas in the hot chamber, causing it to expand and move the hot piston b . This piston then reverses direction, pushing the heated gas into the cold chamber c . As the gas cools, the cold piston can easily compress...
Designer Microbes
Genetic engineers think they can create synthetic life-forms that will let us grow energy as easily as we do food 1 A e view the genome as the software, or even the operat-V V ing system, of the cell, said J. Craig Venter. It's time for an upgrade, he suggested. Venter was preaching to the choir a large group of biologists at the Synthetic Biology 2.0 conference this past May. Many of the scientists there have projects to genetically rewire organisms so extensively that the resulting cells...
A Slow And Steadyand Exceptionally Lengthylife By Steve Mirsky
Four score and seven years and four score and nine more years ago, a tortoise hatched in the Gal pagos. She spent the past half a century known as Harriet. For more than a century before that, she was called Harry. Before that she almost was called dinner, but fate had other plans. Her heart, which began beating when Abraham Lincoln was barely out of his teens, finally stopped on June 23. Her fame came from her longevity and from her celebrity friends. She spent her last years at the Australia...
The Least Bad Fossil Fuel
Although renewable energy sources offer the best way to radically cut greenhouse gas emissions, generating electricity from natural gas instead of coal can significantly reduce the amount of carbon added to the atmosphere. Conventional coal-fired power plants emit 0.25 kilogram of carbon for every kilowatt-hour generated. More advanced coal-fired plants produce about 20 percent less carbon. But natural gas CH4 has a higher proportion of hydrogen and a lower proportion of carbon than coal does....