scientific american - 1994 12 - nasa''s latest view of the earth
scientific american - 1994 12 - nasa's latest view of the earth
... loners. The families have very diÝerent char- acters, which reßect the person- ality of the matriarch. In the case of Echo, the family is low- key and nonaggressive. How the 50-year-long rela- tionships ... proÞt- able segments of the market. Among the models offered for sale in a given year, the more fuel-eÛcient ones tend to be the smaller, slower, bottom -of- the...
Ngày tải lên: 12/05/2014, 14:59
scientific american - 1994 06 - was there a race to the moon
... angular momenta. The eccentricity of the cor- responding elliptical orbit determines the spread. The square of the magni- tude of the wave function gives the probability for Þnding the electron at ... conditions. At the be- ginning of the race, the runners line up at the startÑthat is, they are well local- ized. Each one runs in one of the quan- tized Bohr...
Ngày tải lên: 12/05/2014, 14:56
scientific american - 1993 12 - taming africanized killer bees
... show their gem was not man-made. Evident- ly, a fragment of natural dia- mond seed slipped into their sample. Nevertheless, the pro- cess was correct and eventu- ally enabled them to synthe- size ... ag- gressive in doing what it took to suc- ceed,Ó laments James C. McGroddy, di- rector of the research division. The recent upheavals have accelerat- ed the linking of the work...
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scientific american - 1994 01 - searching for strange quark matter
... professor at and di- rector of the Environmental Institute at the University of Massachusetts at Am- herst. He has studied, among other top- ics, the behavior of beavers and the as- sessment of ... Although 66 SCIENTIFIC AMERICAN January 1994 W etlands are often as different in their appearance and in the species they host as they are in the range of sat- uration t...
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scientific american - 1994 02 - do aerosols slow climatic warming
... fertilizing them in vitro and let- ting them grow to the eight-cell stage. One or two of the cells are then re- moved from the embryo and analyzed by making millions of copies of one bit of the gene of ... types: the F-117 Stealth Þght- ers, F-15s and F-16sÑAmericaÕs top -of- the- line ÞghtersÑand the sturdy A-10 ground-attack airplane. Marine and navy aviation units wi...
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scientific american - 1994 03 - visiting yourself in the past
... which they then use to make predictions. Copyright 1994 Scientific American, Inc.Copyright 1994 Scientific American, Inc. 20 SCIENTIFIC AMERICAN March 1994 In the ÒnaiveÓ quark model, one of the three ... wavelengths. An anal- ysis of the wavelengths and intensities of these x-rays allows a determination of the chemical composition of the min- eral. Collabo...
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scientific american - 1994 04 - the dilemmas of prostate cancer
... of his former critics. Gould, in a review in Na- ture, lauded The Diversity of Life as Òa 38 SCIENTIFIC AMERICAN April 1994 Copyright 1994 Scientific American, Inc.Copyright 1994 Scientific American, ... each cycle of the AC Þeld. When the marble is hopping down the egg tray with the help of the AC Þeld, augmenting the av- erage tilt of the egg tray b...
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scientific american - 1994 07 - how cancers defeat drug therapy
... returned the Þrst samples. The Eagle landed on the surface of a mare in the Sea of Tranquillity, one of the dark gray areas that paint the fea- tures of the man-in -the- moon. They are the remnants of ... and the earth formed in the same region of the evolving solar system. Fi- nally, the hypothesis explains the most diÛcult problem: the angular momen...
Ngày tải lên: 12/05/2014, 14:57
scientific american - 1994 08 - red tides - a growing hazaed
... perpendicular to the axis of rotation of the EUVE satel- lite. This axis lies in the plane of the eclipticÑthat of the earth s orbit around the sunÑand is pointed toward and away from the sun. As the satellite ... now sounds, the young Mayr was not a follower of Dar- win. Rather, like most other naturalists of the day, he subscribed to Jean-Bap- tiste LamarckÕ...
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scientific american - 1994 09 - conquering lyme disease
... superanti- gen, which according to Cleary is wide- ly believed to be the cause of the strep- related toxic-shock syndrome. Cleary also has another study, now in press with the Proceedings of the Na- tional ... this so- called forbidden interaction, they will have evidence of the presence of a new particle. They can then add the particle to the Standard Model, thereby ext...
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