ARTICLES
The Real Threat of Nuclear Smuggling
Phil Williams and Paul N. Woessner
The amount of plutonium needed to build a nuclear weapon could fit inside
two soft drink cans. Much less is needed for other deadly acts of terrorism.
Those facts, coupled with the huge, poorly supervised nuclear stockpiles
in Russia and elsewhere, make the danger of a black market in radioactive
materials all too real. Yet disturbingly little is being done to contain
this menace.
Caloric Restriction and Aging
Richard Weindruch
Want to live longer? Eating fewer calories might help. Although the case
for humans is still being studied, organisms ranging from single cells to
mammals survive consistently longer when fed a well-balanced but spartanly
lo-cal diet. Good news for snackers: understanding the biochemistry of this
benefit may lead to a solution that extends longevity without hunger.
Technology and Economics in the Semiconductor Industry
G. Dan Hutcheson and Jerry Hutcheson
Semiconductor Cassandras have repeatedly warned that chipmakers were approaching
a barrier to further improvements; every time, ingenuity pushed back the
wall. With the cost of building a factory climbing into the billions, a
true slow-down may yet be inescapable.
Even so, the industry can still grow vigorously by working to make microchips
that are more diverse, rather than just faster.
Neural Networks in Vertebrate Locomotion
Sten Grillner
How does the brain coordinate all the muscle movements involved in walking,
running and swimming? It doesn't-some of the control is delegated to local
systems of neurons in the spinal cord. Working with primitive fish called
lampreys, investigators have identified some of this circuitry. These discoveries
raise the prospects for eventually being able to restore mobility to some
accident victims.
Cleaning Up the River Rhine
Karl-Geert Malle
The Rhine is Europe's most economically important river: 20 percent of its
water is diverted for human purposes, and it is a vital artery for shipping
and power. Twenty years ago, pollution had threatened to ruin both the Rhine's
beauty and its utility. International cooperation, however, has now brought
many troublesome sources of chemical contamination under control.
The Evolution of Continental Crust
S. Ross Taylor and Scott M. McLennan
The continents not only rise above the level of the seas, they float atop
far denser rocks below. Of all the worlds in the solar system, only our
own has sustained enough geologic activity through the constant movement
of its tectonic plates to create such huge, stable land masses.
SCIENCE IN PICTURES
Working Elephants
Michael J. Schmidt
In the dense forests of Myanmar (formerly Burma), teams of elephants serve
as an ecologically benign alternative to mechanical logging equipment. Maintaining
this tradition might help save these giants and the Asian environment.
TRENDS IN PHYSICS
Explaining Everything
Madhusree Mukerjee, staff writer
Ever since Einstein, physicists have dreamed of a Theory of Everything-an
equation that explains the universe. Their latest, greatest hope is that
a newly recognized symmetry, duality, may help infinitesimal strings tie
reality together.
DEPARTMENTS
Science and the Citizen
Culture and mental illness.... RNA and the origin of life.... Space junk....
Quantum erasers.... Resistant microbes.... The studs of science.... New
planets.
The Analytical Economist
Gutting social research.
Technology and Business
Breeder reactors: the next generation.... Stair-climbing wheelchair....
Japan on-line.... Fractal-based software.
Profile
Physicist Joseph Rotblat's odyssey to the Nobel Prize for Peace.
Letters to the Editors
Fly the crowded skies.... How much energy?... The dilemmas of AIDS.
50, 100 and 150 Years Ago
1946: Making high-octane gasoline.
1896: The missing link in Java.
1846: Mesmerizing crime.
The Amateur Scientist
How to record and collect the sounds of nature.
Mathematical Recreations
The slippery puzzle under Mother Worm's blanket.
Reviews and Commentaries
The why of sex.... Hypertext....
Wonders, by Philip Morrison: A century of radioactivity.... Connections,
by James Burke: Hydraulics and cornflakes.
Essay: Christian de Duve
The evolution of life was not so unlikely after all.