Letters.Matters of flavor "Physics bedrock cracks, sun shines in" (SN: 6/23/01, p. 388) says that solar neutrinos oscillate To swing back and forth between the minimum and maximum values. An oscillation is one cycle, typically one complete wave in an alternating frequency. between different flavors on the trip to Earth and that those taking a longer path have more time to oscillate into kinds of neutrinos that the sun doesn't produce. Do the scientists note a variation in neutrino neutrino (n  trē`nō) [Ital.,=little neutral (particle)], elementary particle with no electric charge and a very small mass emitted during the decay of certain other particles. types based on the
eccentricity eccentricity, in astronomy: see orbit. Eccentricity Addams Family weird family, presented in grotesque domesticity. [TV: Terrace, I, 29] Boynton, Nanny travels with set of Encyclopaedia Britannica of Earth's orbit? When Earth is closest to the sun, electron neutrinos would have less time to oscillate. Douglas Nelson Salt Lake City, Utah About 7 percent fewer solar neutrinos hit detectors when Earth is furthest from the sun, compared with when it's closest, says Arthur B. McDonald, director of the Sudbury Neutrino Observatory The Sudbury Neutrino Observatory (SNO) was located 6800 feet (about 2 km) underground in CVRD Inco's Creighton Mine in Sudbury, Ontario, Canada. The detector was designed to detect solar neutrinos through their interactions with deuterium nuclei and atomic electrons. in Ontario. However, whether the Earth-sun distance also influences the oscillation of the sun's electron neutrinos into other flavors remains unknown. "It is something we will analyze for in the future, "McDonald says. --P. Weiss Not so clear cut The article "Amazon forest could disappear, soon" (SN: 7/14/01, p. 24) says, "Logging and burning for agriculture currently claim about 1 percent of the Amazon rain forest per year." This simply is not true. We have been hearing this and even more alarming "statistics" about Amazon deforestation deforestation Process of clearing forests. Rates of deforestation are particularly high in the tropics, where the poor quality of the soil has led to the practice of routine clear-cutting to make new soil available for agricultural use. for more than 20 years. Yet NASA NASA: see National Aeronautics and Space Administration. NASA in full National Aeronautics and Space Administration Independent U.S. Landsat images show that little more than 10 percent of the original forest has been cleared. Even if the clearing has been going on for only those 20 years (and it has been proceeding for far longer than that), this amounts to but half of the rate claimed. The facts are, to be sure, troubling, but you do a disservice to those making reasonable efforts to curtail the clearing by restating exaggerated and discredited numbers. G.A. Esworthy Apes, N.C. Current Landsat images show that about 15 percent of the rain forest in Brazil, which makes up 80 percent of the Amazon rain forest, has been deforested, says Mark Cochrane, a research scientist at Michigan State University Michigan State University, at East Lansing; land-grant and state supported; coeducational; chartered 1855. It opened in 1857 as Michigan Agricultural College, the first state agricultural college. in East Lansing East Lansing, city (1990 pop. 50,677), Ingham co., S central Mich., a suburb of Lansing, on the Red Cedar River; inc. 1907. The city was first known as College Park, but was renamed when it was incorporated. . Each year about 0.5 percent of the rain forest there is lost to burning, agriculture, or logging. Nearly an equal amount is substantially degraded by human activity, Cochrane says. Outside Brazil, at least 0.4 percent of the South American rain forest was lost each year between 1986 and 1992. That's the period for which the most recent estimates are available, says Kip Desch, manager of the Deforestation Mapping Group at the University of Maryland's Global Land Cover Facility. --S. Perkins |
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