A Grandmaster Chess Machine
In the 40 years since this magazine published the original prospectus for a chess computer, machines have vanquished first novices, then masters and now grandmasters. Will Gary Kasparov be next?
Volume 263, Issue 4
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Features
Parental Imprinting of Genes
Even when fathers and mothers contribute identical genes to their offspring, the genes may have different effects. Sex-specific gene imprints may influence normal development and trigger diseases
The Photorefractive Effect
A laser beam passing through a crystal can suddenly burst into a spray of light. This photorefractive effect may be the key to developing computers that exploit light instead of electricity
What Caused the Mass Extinction?
An Extraterrestrial Impact
Accumulating evidence suggests an asteroid or comet caused the Cretaceous extinction
A Volcanic Eruption
What dramatic event 65 million years ago killed most species of life on the earth? The author argues it was a massive volcanic eruption
Ocean Acoustic Tomography
Oceanographers are using principles analogous to medical X-ray tomography to obtain three-dimensional images of ocean currents and temperatures
Boron Neutron Capture Therapy for Cancer
A twofold treatment brings together boron and neutrons to create a lethal radiation that can attack tumor cells without damaging normal tissues in the process