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Surely, it would besensibleto get a second opinion before taking any further action.
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WELL—do they or don"t they For years, controversy has raged over whether the electromagnetic fields produced by power lines could cause cancer especially leukemia in young children. But in Britain last week confusion reached new heights. One team from Bristol announced that it had evidence to back a controversial but plausible theory which would explain how power lines might cause cancer(electric fields attract airborne pollutants). Only to be followed by the release of results by another group in London which suggested there is nothing to worry about. What is going on Actually, the confusion may be more apparent than real. There can be no doubt that the effects of power lines on water droplets, pollutants and naturally occurring radon uncovered by the Bristol team are real and interning. But to suggest that they have anything to do with leukemia in children is premature. The extra exposure to pollution for a child living near power lines would be tiny, and it is not obvious why radon, a gas normally associated with lung cancer—would cause leukemia in children. The second study, which drew reassuring blank, is the world" s biggest ever probe of the statistical link between childhood cancers and magnetic fields of the sort produced by power lines and electrical appliances. It is one of several recent studies that have failed to find a link. Unlike earlier research, these newer studies involved going into homes to measure the electromagnetic fields. The fields they measured included input from major power lines if they were. Which is not to say the research is perfectly. Critics argue that Britain" s childhood cancer study, for example, has not yet taken into account the surges in exposure that might come from, say, switching appliances on and off. And some people might wonder why measurements of the electric fields that are also produced by power lines did not figure in last week" s study. But neither criticism amounts to a fatal blow. Electrical fields cannot penetrate the body significantly, for example. A more serious concern is whether the British research provides an all-clear signal for such countries as the US where power lines carry more current and therefore produce higher magnetic fields. Pedants(书呆子)would conclude that it doesn" t. But these counties will not have long to wait for answers from a major Japanese study. In Britain the latest epidemiological study can be taken as the final word on the matter. If the electromagnetic fields in British homes can in some unforeseen way increase the risk of cancer, we can now be as certain as science allows that the increase is too tiny to measure. To conclude, the author______.
Are some people born clever and others born stupid Or is intelligence developed by our environment and our experiences Strangely【C1】______, the answer to both these questions is yes. To some extent our intelligence is given us at birth, and no amount of special education can make a genius【C2】______a child born with low intelligence. On the other hand, a child who lives in boring environment will develop his intelligence less than the one who lives in rich and varied surroundings. Thus the【C3】______of a person" s intelligence are fixed at birth, but whether or not he reaches those limits will depend on his【C4】______This view, not held by most experts, can be supported in a number of ways. It is easy to show that intelligence is to some extent【C5】______we are born with. The closer the blood relationship between two people, the closer they are likely to be in intelligence. Thus if we take two unrelated people【C6】______, it is likely that their degrees of intelligence will be completely different. If on the other hand we take two identical twins they will likely be as intelligent as each other. Relations like brothers and sisters, parents and children, usually have【C7】______intelligence and this clearly suggests that intelligence depends on birth. 【C8】______now that we take identical twins and put them in different environments. We might send one, for example to a university and the other to a factory where the work is boring. We would soon find differences in intelligence developing, and this indicates that environment【C9】______birth plays a part. This conclusion is also suggested by the【C10】______that people who live in close contact with each other,but who are not related at all, are likely to have similar degrees of intelligence. 【C8】
关于无差异曲线的特征的说法，错误的是______。
Smoking causes wrinkles by upsetting the body" s mechanism for renewing skin, say scientists in Japan. Dermatologists say the finding confirms the long-held view that smoking ages skin prematurely. Skin stays healthy and young-looking because of a fine balance between two processes that are constantly at work. The first breaks-down old skin while the second makes new skin. The body breaks down the old skin with enzymes called matrix metalloproteinases, or MMPs, They chop up the fibers that form collagen(胶原质)—the connective tissue that makes up around 80 percent of normal skin. Akimichi Morita and his colleagues at Nagoya City University Medical School suspected that smoking disrupted the body" s natural process of breaking down old skin and renewing it. To test their idea, they first made a solution of cigarette smoke by pumping smoke through a saline(盐的)solution. Smoke was sucked from cigarettes for two seconds every minute. Tiny drops of this smoke solution were added to dishes of human fibroblasts, the skin cells that produce collagen. After a day in contact with smoke solution, the researchers tested the skin cells, to see how much collagen-degrading MMP they were making. Morita found that cells exposed to cigarette smoke had produced far more MMP than normal skin cells. Morita also tested the skin cells to see how much new collagen they were producing. He found that the smoke caused a drop in the production of fresh collagen by up to 40 percent. He says that this combined effect of degrading collagen more rapidly and producing less new collagen is probably what causes premature skin ageing in smokers, in both cases, the more concentrated the smoke solution the greater the effect on collagen. " This suggests the amount of collagen is important for skin ageing," he says. "It looks like less collagen means more wrinkle formation". Morita doesn" t know if this is the whole story of why smokers have more wrinkles. But he plans to confirm his findings by testing skin samples from smokers and non-smokers of various ages to see if the smoking has the same effect on collagen. "So far we" ve only done this in the lab. " he says. " We don"t know exactly what happens in the body yet that might take some time. " Other dermatologists are impressed by file work. "This is fascinating," says Lawrence Parish. Director of the Centre for International Dermatology at Thomas Jefferson University Hospital in Philadelphia. This confirms scientifically what we"ve long expected, he says. "Tobacco smoke is injurious to skin. " Monrita implies that his findings______.
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