Word: cords
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Back at his desk in Houston after the jump, he was rummaging for the names and addresses of all his new skydiving buddies so he could pay up on a penalty--one case of beer--because he'd dropped the rip cord instead of fixing it back on the patch of Velcro. Unwritten rule of the skyways: Recycle your equipment. His fellow jumpers didn't mind a bit, pronouncing his jump "perfect" for a novice. But Bush cared...
Kordus has plenty of partners in anxiety as every lurch in the market--the Dow index did a three-day wiggle and dropped 57.34 points to close at 6931.62 last week--makes skittish investors wonder whether it's finally time to pull the rip cord and cash out. "The average person is very jittery but is still bringing in money in hopes of staying with the bull market," says Robert Coleman, an investment adviser with the firm Christopher Weil & Co. in San Diego. "People are constantly calling and asking, 'What do you think?'" Coleman adds. "I say, 'Relax, stay...
...thin layer of cells in the developing embryo performs an origami-like trick, folding inward to give rise to a fluid-filled cylinder known as the neural tube. As cells in the neural tube proliferate at the astonishing rate of 250,000 a minute, the brain and spinal cord assemble themselves in a series of tightly choreographed steps. Nature is the dominant partner during this phase of development, but nurture plays a vital supportive role. Changes in the environment of the womb--whether caused by maternal malnutrition, drug abuse or a viral infection--can wreck the clockwork precision...
What biochemical magic underlies this incredible metamorphosis? The instructions programmed into the genes, of course. Scientists have recently discovered, for instance, that a gene nicknamed "sonic hedgehog" (after the popular video game Sonic the Hedgehog) determines the fate of neurons in the spinal cord and the brain. Like a strong scent carried by the wind, the protein encoded by the hedgehog gene (so called because in its absence, fruit-fly embryos sprout a coat of prickles) diffuses outward from the cells that produce it, becoming fainter and fainter. Columbia University neurobiologist Thomas Jessell has found that it takes middling concentrations...
...recent finding has intrigued researchers more than the results reported in October by Corey Goodman and his Berkeley colleagues. In studying a deceptively simple problem--how axons from motor neurons in the fly's central nerve cord establish connections with muscle cells in its limbs--the Berkeley researchers made an unexpected discovery. They knew there was a gene that keeps bundles of axons together as they race toward their muscle-cell targets. What they discovered was that the electrical activity produced by neurons inhibited this gene, dramatically increasing the number of connections the axons made. Even more intriguing, the signals...