Letters.No stone unturned I am writing in response to an article in the July 28 issue, "Having gathered moss, water drops roll" (SN: 7/28/01, p. 57). You should have taken the time to find out that Lycopodium is not a moss. It's true that a common name for the plant is club moss, but Lycopodium is in the division Lycophyta, sometimes called seedless Seed´less a. 1. Without seed or seeds. Adj. 1. seedless - lacking seeds; "seedless grapefruit" seedy - full of seeds; "as seedy as a fig" seedless adj → vascular plants or fern allies. Ann E. Rushing Baylor University Waco, Texas You report inaccurately that water droplets normally "dribble like tears down a slanting surface." Close observation will show that every solo trickle of water in fact has a well-defined spherical head. It's quick and easy to miss, but definitely observable. Because it usually leaves a trail as it rolls down the surface, a solo trickle may seem to be tear-shaped, but actual tear-shaped drops are only the ones that have not broken the grip of surface tension adhesion. Other easily observed "liquid marbles" are found almost any time you turn a water hose on the top of a car, especially if the spray is backlit An LCD screen that has its own light source from the back of the screen, making the background brighter and characters appear sharper. by the sun. You almost always see a profusion of little spheres bouncing and scattering without adhesion over the wet surface. Phil Henshaw New York, N. Y. Where there's smoke
The study in "Marijuana may boost heart attack risk" (SN: 7/14/01, p. 31) appears to be more about the effects of smoking and deep inhalation than a useful examination of the effects of tetrahydrocannabinol tetrahydrocannabinol /tet·ra·hy·dro·can·nab·i·nol/ (THC) (-hi?dro-kah-nab´i-nol) the active principle of cannabis, occurring in two isomeric forms, both considered psychomimetically active. , which is what marijuana smokers seek. The report makes it sound as though this active ingredient is the cause of the marginal increase in heart attacks, whereas it is probably due to smoking--whether that be of marijuana, tobacco, or oak leaves. Marijuana smokers inhale unfiltered Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. Remove this template after wikifying. This article has been tagged since smoke and hold it in their lungs for a prolonged period. A major component of this smoke (as well as that of cigarettes) is carbon monoxide carbon monoxide, chemical compound, CO, a colorless, odorless, tasteless, extremely poisonous gas that is less dense than air under ordinary conditions. It is very slightly soluble in water and burns in air with a characteristic blue flame, producing carbon dioxide; . This will cause, of course, a sudden reduction in blood-oxygen partial pressure and affect a heart already partially oxygen-compromised by coronary artery disease coronary artery disease, condition that results when the coronary arteries are narrowed or occluded, most commonly by atherosclerotic deposits of fibrous and fatty tissue. . Peter Nelson, Nevada City, Calif. Send communications to: Editor, SCIENCE NEWS 1719 N Street, N.W. Washington, D.C. 20036 or scinews@sciserv.org All letters subject to editing. |
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