The Amateur Scientist

Roger Baker Amateur Scientist

In January of last year I described a delightful device for detecting microfluctuations in the earth's magnetic field. The instrument was a sensitive torsion balance consisting of two small rare-earth magnets affixed to a taut nylon fiber with a tiny mirror attached to the fiber to reflect a laser beam onto a distant wall. When the instrument was properly nulled with additional magnets to cancel the earth's average magnetic field, an infinitesimal change in the earth's field rotated the...

Cotton

Constitute the heart of the biological clock in flies, and with some modifications they appear to form a mechanism governing circadian rhythms throughout the animal kingdom, from fish to frogs, mice to humans. Recently Steve Reppert's group at Harvard and Justin Blau in my laboratory have begun to explore the specific signals connecting the mouse and fruit fly biological clocks to the timing of various behaviors, hormone fluctua tions and other functions. It seems that some output genes are...

Pheromone

PHEROMONE TRAILS enable ants to forage efficiently. Two ants leave the nest at the same time (fop),each taking a different path and marking it with pheromone.The ant that took the shorter path returns first (bottom). Because this trail is now marked with twice as much pheromone, it will attract other ants more than the longer route will. DIFFERENT FOOD SOURCES are raided sequentially because of pheromone evaporation. In this computer simula-tion,three identical sources of food are located at...

Brain Invaders

A new auditory prosthesis implanted directly into the brain stem may restore hearing For tens of thousands of profoundly deaf adults and children worldwide, cochlear implants have provided a useful substitute for natural hearing. These devices electrically stimulate the auditory nerve within the cochlea, enabling many users to carry on a conversation without visual cues, such as over the telephone. But for patients whose nerve endings have degenerated or whose auditory nerves have been...

Info

Micrograph of an ant by Dennis Kunkel Phototake. Discover why a mother's immune system ignores the child in her womb www.sciam.com explorations 2000 012400preg Check every week for original features and this month's articles linked to science resources on-line. Scientific American (ISSN 0036-8733),published monthly by Scientific American,Inc.,415 Madison Avenue,New York,N.Y.10017-1111. Copyright 2000 by Scientific American,Inc.All rights reserved.No part of this issue may be reproduced by any...

Of The Atlantic Forest

FRAGMENTS of the Brazilian Atlantic Forest are often found around densely populated areas on the coast. This Alcantarea gla-ziouana (1), for instance, was discovered above the city of Niteroi, which is just east of Rio de Janeiro. Retrieving the specimens is not always so easy, however. Often biologists have to climb high trees or scale steep inclines, as Thelma Barbar did when she tried to collect Dyckia encholiri-oides (2). But sometimes the brilliant hues of a bromeliad in bloom help the...