Fertile Ground

IVF researchers pioneer the bioethical frontier When researchers at George Washington University cloned 17 dysfunctional human embryos last summer, they were testing a possible new tool for in vitro fertilization (IVF). Their experiment opened a Pandora's box of hypothetical moral concerns an increasingly familiar experience in IVF research among them the prospect that many identical copies of an individual might someday be created. But the public uproar that followed has obscured a much more...

US forces were shaped for conflict with a superpower The emerging multilateral world calls for a smaller more flexible

By Philip Morrison, Kosta Tsipis and Jerome Wiesner In October 1981 President Ronald Reagan announced the beginning of the biggest military buildup ever undertaken by a nation in peacetime. Over the next decade the U.S. spent more than 3 trillion (three quarters of the current national debt) on its military. Fully 60 percent of those costs were devoted to countering the threat of communism. That tremendous expenditure marked the culmination of the 50-year competition with the Soviet Union, a...

Blade of Grass

Social history often returns to the theme of the lawn versus crabgrass. Properly nurtured, suburban sod serves as a symbol of gentility and social superiority. Dominance over the encroachments of chickweed, par-tridgeberries, plantains, rushes and innumerable other undesirable forms of vegetation proclaims the orderliness, the rightness of an existence distanced from the rigors of urban living. F. Herbert Bormann, an emeritus professor of forest ecology at the Yale University School of Forestry...

These huge swift creatures were the dominant carnivores of the continent for millions of years until competitors drove

Phorusrhacos Longissimus

It is a summer day on the pampas of central Argentina some five million years ago. A herd of small, horselike mammals are grazing peacefully in the warm sun. None of the animals is aware of the vigilant creature standing 50 meters away in the tall grass. Most of the watcher's trim, feathered body is concealed by the vegetation. Its eyes, set on the sides of a disproportionately large head perched on a long and powerful neck, are fixed on the herd. The head moves from side to side in short,...

Users and HIV Infection

Are infected with the human immunodeficiency virus, but it is unclear how many of them were infected through injection or through sex with a drug user. In the U.S., however, one third of all AIDS cases can be attributed to drug injection. of American culture from T-shirts and blue jeans to fast food many different countries have adopted the practice. The fact that cocaine, heroin and related drugs are illegal encourages the use of injection. Severe statutory restrictions greatly increase the...

Liquid Mirror Telescopes at Work

Homemade Telescope Liquid Mirror

A mirror, three meters in diameter, made recently by the National Aeronautics and Space Administration bottom left will search for space debris. The diagram top shows how the mirror works. The mirror and bearing rest on a three-point mount the axis of rotation is aligned vertically using two adjustable screws. A synchronous electric motor, connected by pulleys and a belt, drives the turntable under the mirror's container. An AC power supply, stabilized with a crystal oscillator, controls the...