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“Salmon hatcheries can deplete wild stocks” ignores a basic fact. Hatchery stocks came from wild stocks. Their DNA is the same. There is an abundance of underused habitat in our northwest rivers. Some hatchery salmon would use these habitats if they were left alone. Instead, hatchery fish are clubbed to death to prevent their mixing […]
- Earth
Salmon hatcheries can deplete wild stocks
Hatchery fish appear to be replacing wild salmon populations in the Columbia River.
- Planetary Science
Asteroid Eros poses a magnetic puzzle
Measurements with a magnetometer aboard the NEAR-Shoemaker spacecraft a few days after it landed on the asteroid 433 Eros confirmed a major puzzle: The rock has no detectable magnetic field.
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Insects deploy sticky feet with precision
Sticky ant and bee footpads retract and unfold in time with insect steps, so the insects don't trip over their own sticky feet.
- Health & Medicine
Does breast-feeding accelerate AIDS?
A study of HIV-infected mothers in Kenya suggests that breast-feeding places them at a health risk.
- Chemistry
Molecular Chemistry Takes a New Twist
New calculations show that a basic tenet of chemistry is wrong: Ethane forms its most stable structure not due to so-called steric effects, but because of a quantum mechanical influence.
- Physics
Stretching and twisting a bright idea
A new, stretchy type of liquid-crystal component makes it possible to change a laser's color by simply pulling on the membrane—a much easier, cheaper means of adjustment than that used for today's complex and expensive tunable lasers.
- Physics
In a squeeze, nitrogen gets chunky
Remarkable already for being a semiconductor and, perhaps, an explosive, a new, solid form of nitrogen made by crushing the ordinary gas to the highest pressures ever also stands out because it continues to survive when the pressure is released.
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From the May 30, 1931, issue
LIFE IS RARE IN UNIVERSE, ASTRONOMER BELIEVES Life is a rare phenomenon in the universe, Sir James Jeans, British astronomer, assured the Franklin Institute meeting at which he was presented the Franklin Medal, one of Sciences highest awards. I leave it to you to be pleased or not, Sir James said, at a large fraction […]
- Earth
Daily Planet Earth
The Earth Science Picture of the Day Web site features photos, satellite images, and illustrations that highlight the diverse processes and phenomena shaping our planet and influencing our lives. A short explanatory caption and links to sources for more detailed information accompany each illustration. Go to: http://epod.usra.edu/
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- Anthropology
Evolution’s Youth Movement
The fossils of ancient children may provide insights into the evolution of modern Homo sapiens.
