Scientific American Magazine

To judge the progress in the war against cancer one must understand the role of trial and error in the evolution of medicine and know something about the natural history of the commoner forms of cancer

After decades of fruitless search astronomers have found a source of high-energy particles and gamma rays bombarding the earth. The object is thought to be a binary stsr at the edge of galaxy

The calcium ion controls processes ranging from muscle contraction to cell division. An array of proteins that are specialized for binding calcium regulate its concentration in the cell and mediate its effects

They are fault-bounded blocks of crust that accrete to the ancient cores of the continents. The process makes the continents increase in extent and reworks them into what amount to geologic collages

It can supplement or replace breathing through lungs or gills. Special adaptations of the skin and the circulatory system help to regulate the cutaneous exchange of oxygen and carbon dioxide

Human-powered aircraft exploit a little-understood Bight regime. Aircraft that can negotiate it are fun to fly and may turn out to have uses in reconnaissance and planetary science

Cards containing microcircuitry are more versatile and securer than conventional credit cards. A microelectronic chip must meet severe constraints to function in this unique environment

Survival of the ances tors of the modern Eskimos and Aleuts hinged on the rela tion between culture and resources. One key to success appears to have been the capacity to exploit many sources of food