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Scientists have long understood that supermassive black holes weighing millions or billions of suns can tear apart stars that come too close. The black hotels gravity pulls harder on the nearest part of the star, an imbalance that pulls the star apart over a period of minutes or hours, once it gets close enough. Scientists say this uneven pulling is not the only hazard facing the star. The strain of these unbalanced forces can also trigger a nuclear explosion powerful enough to destroy the star from within. Matthieu Brassart and Jean-Pierre Luminet of the Observatoire de Paris in Meudon, France, carried out computer simulations of the final moments of such an unfortunate star’s life, as it veered towards a supermassive black hole. When the star gets close enough, the uneven forces flatten it into a pancake shape. Some previous studies had suggested this flattening would increase the density and temperature inside the star enough to trigger intense nuclear reactions that would tear it apart. But other studies had suggested that the picture would be complicated by shock waves generated during the flattening process and that no nuclear explosion should occur. The new simulations investigated the effects of shock waves in detail, and found that even when their effects are included, the conditions favor a nuclear explosion. " There will be an explosion of the star — it will be completely destroyed," Brassart says. Although the explosion obliterates the star, it saves some of the star’s matter from being devoured by the black hole. The explosion is powerful enough to hurl much of the star’s matter out of the black hole’s reach, he says. The devouring of stars by black holes may already have been observed, although at a much later stage. It is thought mat several months after the event that rips the star apart, its matter starts swirling into the hole itself. It heats up as it does so, releasing ultraviolet light and X-rays. If stars disrupted near black holes really do explode, then they could in principle allow these events to be detected at a much earlier stage, says Jules Hatpern of Columbia University in New York, US2. "It may make it possible to see the disruption of that star immediately if it gets hot enough," he says. Brassart agrees. "Perhaps it can be observed in the X-rays and gamma rays, but it’s something that needs to be more studied," he says. Supernova researcher Chris Fryer of the Los Alamos National Laboratory in Los Alamos, New Mexico, US3, says the deaths of these stars are difficult to simulate, and he is not sure whether the researchers have proven their case that they explode in the process. According to the third paragraph, researchers differed from each other in the problem of ______.
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Historians have only recently begun to note the increase in demand for luxury goods and services that took place in 18th-century England. McKendrick has explored the Wedgwood firm’s remarkable success in marketing luxury pottery; Plumb has written about the proliferation of provincial theaters, musical festivals, and children’s toys and books. While the fact of this consumer revolution is hardly in doubt, three key questions remain: Who were the consumers What were their motives And what were the effects of the new demand for luxuries An answer to the first of these has been difficult to obtain. Although it has been possible to infer from the goods and services actually produced what manufactures and servicing trades thought their customers wanted, only a study of relevant personal documents written by actual consumers will provide a precise picture of who wanted what. We still need to know how large this consumer market was and how far down the social scale the consumer demand for luxury goods penetrated. With regard to this last question, we might note in passing that Thompson, while rightly restoring laboring people to the stage of 18th-century English history, has probably exaggerated the opposition of these people to the inroads of capitalist consumerism in general; for example, laboring people in eighteenth-century England readily shifted from home-brewed beer to standardized beer produced by huge, heavily capitalized urban breweries. To answer the question of why consumers became so eager to buy, some historians have pointed to the ability of manufacturers to advertise in a relatively uncensored press. This, however, hardly seems a sufficient answer. McKendrick favors a Veblen model of conspicuous consumption stimulated by competition for status. The "middling sort" bought goods and services because they wanted to follow fashions set by the rich. Again, we may wonder whether this explanation is sufficient. Do not people enjoy buying things as a form of self-gratification If so, consumerism could be seen as a product of the rise of new concepts of individualism and materialism(a preoccupation with or stress upon material rather than intellectual or spiritual things), but not necessarily of the frenzy for conspicuous competition. Finally, what were the consequences of this consumer demand for luxuries McKendrick claims that it goes a long way toward explaining the coming of the Industrial Revolution. But does it What, for example, does the production of high-quality pottery and toys have to do with the development of iron manufacture or textile mills It is perfectly possible to have the psychology and reality of a consumer society without a heavy industrial sector. That future exploration of these key questions is undoubtedly necessary should not, however, diminish the force of the conclusion of recent studies: the insatiable demand in eighteenth-century England for frivolous as well as useful goods and services foreshadows our own world. In the first paragraph, the author mentions McKendrick and Plumb most probably in order to ______.
发展中国家的人们若为移民问题操心，往往是想到硅谷或发达国家的医院和大学去创造自己最辉煌的未来。英国、加拿大和澳大利亚等国给大学毕业生提供的优惠移民政策，就是为了吸引这部分人群。诸多研究表明，发展中国家受过良好教育的人才往往可能有移民倾向。2004年，曾针对印度家庭进行过一次大型调查，结果发现，近40％有移民倾向的人受过中学以上教育，而25岁以上的印度人只有约3．3％受过中学以上教育。“人才流失”问题长期以来一直让发展中国家的决策者很苦恼，他们担心这种情况会危及其经济发展，夺去他们紧缺的技术人才，而这些人才本该在他们自己的大学任教，在他们自己的医院工作，为他们自己的工厂研发新产品。
Our culture has caused most Americans to assume not only that our language is universal but that the gestures we use are understood by everyone. We do not realize that waving good-bye is the way to summon a person from the Philippines to one’s side, or that in Italy and some Latin-American countries, curling the finger to oneself is a sign of farewell. Those private citizens who sent packages to our troops occupying Germany after World War II and marked them GIFT to escape duty payments did not bother to find out that " Gift" means poison in German. Moreover, we like to think of ourselves as friendly, yet we prefer to be at least 3 feet or an arm’s length away from others. Latins and Middle Easterners like to come closer and touch, which makes Americans uncomfortable. Our linguistic and cultural blindness and the casualness with which we take notice of the developed tastes, gestures, customs and languages of other countries, are making us lose friends, business and respect in the world. Even here in the United States, we make few concessions to the needs of foreign visitors. There are no information signs in four languages on our public buildings or monuments; we do not have multilingual guided tours. Very few restaurant menus have translations, and multilingual waiters, bank clerks and policemen are rare. Our transportation systems have maps in English only and often we ourselves have difficulty understanding them. When we go abroad, we tend to cluster in hotels and restaurants where English is spoken. Then attitudes and information we pick up are conditioned by those natives—usually the richer—who speak English. Our business dealings, as well as the nation’s diplomacy, are conducted through interpreters. For many years, America and Americans could get by with cultural blindness and linguistic ignorance. After all America is the most powerful country of the free world, the distributor needed funds and goods. But all that is past. American dollars no longer buy all good things, and we are slowly beginning to realize that our proper role in the world is changing. A 1979 Harris poll reported that 55 percent of Americans want this country to play a more significant role in world affairs; we want to have a hand in the important decisions of the next century, even though it may not always be the upper hand. The author gives many examples to criticize Americans for their______.
对于一个企业来说，既想产品上一个档次，又不加大科研方面的投入，这是不可能的。以下哪项所表达的意思与上文最为接近
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