Letters.A fusion success story Occasionally, one of the many roadblocks to controlled fusion yields to advancing knowledge ("Fusion fuel zips to core through back door," SN: 5/22/99, p. 327). However, we can already get energy from fusion at a cost only slightly higher than that of fossil fuels. There is a fusion reactor Noun 1. fusion reactor - a nuclear reactor that uses controlled nuclear fusion to generate energy thermonuclear reactor nuclear reactor, reactor - (physics) any of several kinds of apparatus that maintain and control a nuclear reaction for the production of 93 million miles from Earth. Solar heating solar heating Use of solar radiation to heat water or air in buildings. There are two types: passive and active. Passive heating relies on architectural design; the building's siting, orientation, layout, materials, and construction are utilized to maximize the heating , plus electricity from photovoltaics, wind, and hydro, already contributes substantially to the world's energy supply. It's not clear if controlled fusion can ever produce energy that is competitive with other sources. Research on solar energy solar energy, any form of energy radiated by the sun, including light, radio waves, and X rays, although the term usually refers to the visible light of the sun. and efficient technologies will produce more energy, decades sooner, than research on controlled fusion. Robert Baillie Loveland, Colo. An outside line Some think the child's skeleton in Portugal is a hybrid of Neandertal and Homo sapiens ("Fossil may expose humanity's hybrid roots," SN: 5/8/99, p. 295). Others think it just is a robust child of non-Neandertal lineage. What about the possibility that it was hybrid and sterile? This would explain why Neandertals and non-Neandertals lived at the same time in the Middle East in separate lines. A long period of separate lines living in the same area would imply sterile hybrids. Kenneth Elder Austin, Texas I was fascinated to read in your May 8 issue that Neandertal expert Erik Trinkaus was convinced by "the huge `snowplow' jaw, large front teeth, short legs, and broad chest" on a fossil that Neandertals and Homo sapiens did some interbreeding interbreeding crossbreeding, as between half-breds. . If that is enough to convince him of hybridization hybridization /hy·brid·iza·tion/ (hi?brid-i-za´shun) 1. crossbreeding; the act or process of producing hybrids. 2. molecular hybridization 3. , he did not have to look so far. Tune in NBC NBC in full National Broadcasting Co. Major U.S. commercial broadcasting company. It was formed in 1926 by RCA Corp., General Electric Co. (GE), and Westinghouse and was the first U.S. company to operate a broadcast network. television at 11:35 p.m. for a living human being showing these characteristics. Don Barnhouse King of Prussia, Pa. Ready to rumble I found "Battle of the sexes" (SN: 5/15/99, p. 312) unreasonable. A mammalian offspring, no matter who its father is, cannot profit from the death or ill health of its mother prior to weaning weaning, n the period of transition from breast feeding to eating solid foods. weaning the act of separating the young from the dam that it has been sucking, or receiving a milk diet provided by the dam or from artificial sources. . Death then means the offspring will die, and ill health means the offspring will be badly fed. However, if a promiscuous mother has offspring in the same litter by multiple fathers, sibling rivalry sibling rivalry Psychology The intense, emotional competition among siblings–brothers and/or sisters that pits one against the other to obtain parental affection, approval, attention, and love. See Cain complex. Cf Oy child, Sibling relational problem. makes sense. The larger embryos and babies will win in a competition for food, perhaps bad for the mother but good for the father, who wants only his offspring to survive. Harriet Pearlman Highland Park, N.J. While natural selection would not likely favor the paternal genes that actually kill the mother during childbirth or prevent her essential care of newborns, it could favor genes that take mother and her embryo near that precipice. --J. Travis |
|
||||||||||||
Printer friendly
Cite/link
Email
Feedback
Reader Opinion