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Evolutionary theories. The Belgian George Lemaitre proposed the idea that about 20000 million years ago all the matter in the universe—enough, he estimated, to make up a hundred thousand million galaxies—was all concentrated in one small mass, which he called the "primeval atom". This primeval atom exploded for some reasons, sending its matter out in all directions, and as the expansion slowed down, a steady state resulted, at which time the galaxies formed. Something then upset the balance and the universe started expanding again, and this is the state in which the universe is now. There are variations on this theory: it may be that there was no steady state. However, basically, evolutionary theories take it that the universe was formed in one place at one point in time and has been expanding ever since.Will the universe continue to expand It may be that the universe will continue to expand for ever, but some astronomers believe that the expansion will slow down and finally stop. Thereafter the universe will start to contract until all the matter in it is once again concentrated at one point. Possibly the universe may oscillate for ever in this fashion, expanding to its maximum and then contracting over again.The steady-state theory. Developed at Cambridge by Hoyle, Gold and Bodi, the steady-state theory maintains that the universe as a whole has always looked the same and always will. As the galaxies expand away from each other, new material is formed in some ways between the galaxies and makes up new galaxies to take place of those which have receded. Thus the general distribution of galaxies remains the same. How matter could be formed in this way is hard to see, but no harder than seeing why it should all form in one place at one time.How can we decide which of these theories is closer to the truth The method is in principle quite simple. Since the very distant galaxies are thousands of millions of light years away, then we are seeing them as they were thousands of millions of years ago. If the evolutionary theory is correct, the galaxies were closer together in the past than they are now, and so distant galaxies ought to appear to be closer together than nearer ones. According to the steady-state theory there should be no difference.The evidence seems to suggest that there is a difference, that the galaxies were closer together than they are now, and so the evolutionary theory is partially confirmed and the steady-state theory—in its original form at least—must be rejected. We see distant galaxies as they were long, long ago because().
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They cannot stay organized. They finish their homework but then lose it. And they often have trouble focusing in class. In schools across the U. S. young boys are falling behind, while young girls are thriving. Once again, learning differences between the sexes have become a big issue for educators in American schools.In classrooms across the U. S. , there is a new trend that worries educators. In every category and demographic group, boys are falling behind in school.Anita Doyle is a learning specialist who works with kids who are having academic troubles at the private Episcopal High School outside Washington D. C."In this year’s freshman class, I met about five girls and about 30 boys but I have continued to meet with the boys and I don’t see any of the girls. All of the girls have kind of figured out how to do things and they are on their own. Between myself and another learning specialist we meet with about 20 other boys," she says.Episcopal is an elite private high school that admits students based on standardized test scores and grades. Students are generally of similar academic ability.Yet Anita Doyle still sees dramatic differences In performance between the sexes. "A 14-year-old girl is academically more mature than a 14-year-old boy. This makes a huge difference, especially in the high school years. Because, what you are asking of high schoolers is to keep track of five or six subjects, plan ahead for their long term projects, decide what is important to study, to review for tests, and to prioritize, And many boys are not ready to do that task."Recent scientific research suggests that many of these differences may be hard-wired in the brain. Boys mature a year or more later than girls, and are twice as likely to have a learning disability. They tend to fidget and lose focus easily. Brain studies suggest they process language and emotions less efficiently than girls. Boys in the U. S. bring home 70 percent of poor or failing grades and receive the bulk of school suspensions.Twenty years ago, it was the girls who had fallen behind, and efforts to improve their academic performance included hiring more female teachers, who were sensitive to girls’ needs.That has had an impact on boys, says Alvaro Devicente, the Headmaster of The Heights School, a private all-boys school in the Washington area. "I think that in many eases boys are falling behind because there hag been a process over the last 20 years, a process of education becoming more feminine," he said. "And I mean that in sort of a realistic factual sense. Because if you look at the statistics there is a majority of women teachers and a majority of girls in the school that everything gets tailored to the girls and the young women."Armed with the latest statistics, many parents are abandoning the idea of gender equality in schools, acknowledging the differences between the sexes, and turning to same-sex education. The faculty of The Heights School is all male and caters to what Devicente says are the special learning needs of young boys."There have been studies, very interesting studies about how boys hear differently than girls," Devicente notes. "For a boy to really hear the tone, the volume has to ha louder. So if the teacher is speaking at a volume that is comfortable for girls, the boy is going to get distracted because it is like elevator music almost. You start looking around and you are surely going to find a distraction if you are a 12-year-old in a classroom."At the Heights school, boys are given four breaks a day. They are allowed to play tackle football, throw snowballs and vent all of their pent-up energy. Mr. Devieente says that improves their concentration in class."I think that one thing that may happen in other schools is that the way that they try to control boys is by thwarting their passion," he says. "Keeping a lid on them and getting them to do the right thing. And that is very dangerous because you can’t ask a boy to fake it. You have to redirect his passion, and they are going to be passionate and they should be passionate."Ms. Doyle, says it is not a character flaw. "You have got to understand that the way boys behave is not a character flaw. It is who they are," she says. "So you have to start with that premise. You have to start at a situation where they can see what they are capable of."Most educators agree that a wholesale change of teaching practices in schools runs the risk of doing more harm than good. But many believe accepting that differences do exist between the sexes is a starting point for realizing the full potential of every student. Learning specialists found most boys are having, while young girls are thriving in schools.
Birds that are literally half-asleep—with one brain hemisphere alert and the other sleeping—control which side of the brain remains awake, according to a new study of sleeping ducks.Earlier studies have documented half-brain sleep in a wide range of birds. The brain hemispheres take turns sinking into the sleep stage characterized by slow brain waves. The eye controlled by the sleeping hemisphere keeps shut, while the wakeful hemisphere’s eye stays open and alert. Birds also can sleep with both hemispheres resting at once.Decades of studies of bird flocks led researchers to predict extra alertness in the more vulnerable, end-of-the-row sleepers. Sure enough, the end birds tended to watch carefully on the side away from their companions. Ducks in the inner spots showed no preference for gaze direction.Also, birds dozing at the end of the line resorted to single-hemisphere sleep, rather than total relaxation, more often than inner ducks did. Rotating 16 birds through the positions in a four-duck row, the researchers found outer birds half-asleep during some 32% of dozing time versus about 12% for birds in internal spots."We believe this is the first evidence for an animal behaviorally controlling sleep and wakefulness simultaneously in different regions of the brain," the researchers say.The results provide the best evidence for a long-standing supposition that single-hemisphere sleep evolved as creatures scanned for enemies. The preference for opening an eye on the lookout side could be widespread, he predicts. He’s seen it in a pair of birds dozing side-by-side in the zoo and in a single pet bird sleeping by a mirror. The mirror-side eye closed as if the reflection were a companion and the other eye stayed open.Useful as half-sleeping might be, it’s only been found in birds and such water mammals as dolphins, whales, and seals. Perhaps keeping one side of the brain awake allows a sleeping animal to surface occasionally to avoid drowning.Studies of birds may offer unique insights into sleep. Jerome M. Siegel of the UCLA says he wonders if birds’ half-brain sleep "is just the tip of the iceberg". He speculates that more examples may turn up when we take a closer look at other species. The example of a bird sleeping in front of a mirror indicates that ().
World leaders met recently at United Nations headquarters in New York City to discuss the environmental issues raised at the Rio Earth Summit in 1992. The heads of state were supposed to decide what further steps should be taken to halt the decline of Earth’s life-support systems. In fact, this meeting had much the flavour of the original Earth Summit. To wit: empty promises, hollow rhetoric, bickering between rich and poor, and irrelevant initiatives. Think U.S. Congress in slow motion. Almost obscured by this torpor is the fact that there has been some remarkable progress over the past five years--real changes in the attitude of ordinary people in the Third World toward family size and a dawning realisation that environmental degradation and their own well-being are intimately, and inversely, linked. Almost none of this, however, has anything to do with what the bureaucrats accomplished in Rio. Or it didn’t accomplish. One item on the agenda at Rio, for example, was a renewed effort to save tropical forests. (A previous UN-sponsored initiative had fallen apart when it became clear that it actually hastened deforestation)After Rio, a UN working group came up with more than 100 recommendations that have so far gone nowhere. One proposed forestry pact would do little more than immunizing wood-exporting nations against trade sanctions. An effort to draft an agreement on what to do about the climate changes caused by CO2 and other greenhouse gases has fared even worse. Blocked by the Bush Administration from setting mandatory limits, the UN in 1992 called on nations to voluntarily reduce emissions to 1990 levels. Several years later, it’s as if Rio had never happened. A new climate treaty is scheduled to be signed this December in Kyoto, Japan, but governments still cannot agree on these limits. Meanwhile, the U. S. produces 7% more CO2 than it did in 1990 ,and emissions in the developing world have risen even more sharply. No one would confuse the "Rio process" with progress. While governments have dithered at a pace that could make drifting continents impatient, people have acted. Birth-rates are dropping faster than expected, not because of Rio but because poor people are deciding on their own to reduce family size. Another positive development has been a growing environmental consciousness among the poor. From slum dwellers in Karachi, Pakistan, to colonists in Rondonia, Brazil ,urban poor and rural peasants alike seem to realize that they pay the biggest price for pollution and deforestation. There is cause for hope as well in the growing recognition among business people that it is not in their long-term interest to fight environmental reforms. John Browne, chief executive of British Petroleum, boldly asserted in a major speech in May that the threat of climate change could no longer be ignored. What did the UN call on nations to do about CO2 and other greenhouse gases in 1992().
W: Professor Williams, I’m a student of your art class. I feel very interested in Japanese art, especially when you were saying that there is close relationship between Japanese art and Chinese art. Can you tell me something more about itM: No problem. What do you want to knowW: How did the relations startM: Well, that was in the 7th century when the first temples were built in Japan, the first pictures were painted, and the first sculptures were made. At that time, all branches of art were already highly developed in China.W: You mean that the Japanese first learnt art from ChinaM: Not so exactly. The earliest works of art in Japan were mostly done by Chinese and Korean artists who went to Japan from the 6th century on.W: How long did that lastM: That continued until about the 9th century. For that period, if you want to understand Japanese art, you have to know something of Chinese art first.W: What happened after thatM: In the 10th century the once mighty Chinese Empire of the Tang Dynasty was in a state of constant war and disintegration. Then Japanese art began to acquire a character of its own. Paintings and sculptures with the unusual Japanese gracefulness emerged from then on.W: So that relationship came to an endM: Not so exactly. Actually, in the 13th century there was a new wave of Chinese influence. The sculpture at that time echoes Chinese sculpture of the Song Dynasty. In the early 17th century, the art of distinctive Japanese features was truly established. But the influence of Chinese art continued. Even now you can find that influence in much of modern Japanese art, though often it’s a combination with other styles... [fade out] When did Japanese art really take a form().
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