gjw

Human populations near the equator have evolved dark skin over many generations because of exposure to the fiercest rays of the sun, A similar phenomenon has also occurred in other parts of the animal kingdom. The African grass mouse is a good example. Most mice are nocturnal, but the African grass mouse is active during daylight hours. This means that it spends its days searching for food in the semi-dry bush in scrubby habitats of eastern and southern Africa. Its furry stripe’s
like a chipmunk’s, which helps it blend in with its environment,. Because it spends a lot of time in the intense tropical sun, the grass mouse has also evolved two separate safeguards against the sun’s ultraviolet radiation. First, like the population of humans in this region of the world, the skin of the grass mouse contains lots of melanin, or dark pigment. Second and quite unusual, this mouse has a layer of melanin-pigmented tissue between its skull and skin. This unique cap provides an extra measure of protection for the grass mouse and three other types of African mouse, like rodents that are active during the day. The only other species scientists has identified with the same sort of skull adaptation is the white tent-making bat of the Central American tropics. Although these bats sleep during the day, they do so curled up with their head exposed to the sun.

popcornwl

(*^__^*) 嘻嘻……，，要每天坚持哦，，，
哎，，虽然自己也做不到，，，但希望你可以做到，，

gjw

谢谢啦，我会坚持的！！！

gjw

Today I’d like to talk about the sculptor Henry Moore, in particular the ideas his work is based on, and also how he viewed the medium of sculpture. Moore said that to appreciate sculpture a person needs to respond to form in all of its 3 dimensions. He believed that this is more difficult than responding to art that is done on a flat surface, a surface such as canvas that has only 2 dimensions. For example, when you’re looking at a painting, you don’t have to walk around it. You don’t relate to form and shape in the same way you do when looking at sculpture. Moore paid great attention to shapes in nature such as that of bones and shells and stones. He thought that if you could appreciate the shape of something simple, like a stone, then you could go on to appreciate more complex forms. He noticed that many of the stones he picked up had holes in them. One distinctive feature of Moore’s sculpture is his use of holes or opening to emphasize that he is indeed working in a 3 dimensional medium. He believed that the shape of a hole itself could have as much meaning as that of a slid mass and could even help create a sense of mass or volume. Moore was also interested in representing the human figure, which he sculpted in such materials as bronze, stone, and wood. His sculptures of humans contained one person as in the work Reclining Figure or several people as in the sculpture Family Group.

[ 本帖最后由 gjw 于 2008-8-24 16:40 编辑 ]

gjw

By the end of the term, I hope you’ll be convinced as I am that formal writing always requires revision. Sometimes it requires a fairly major rewriting of the paper. Some students may have mistaken idea that revision means simply making corrections in spelling and grammar. I call that “proofreading”. What I expect you to do is you revise, is to evaluate and improve the overall effectiveness of your paper. But how can you tell if your paper is effective? Well, for example, start by asking yourself these questions: is the topic restricted enough to be fully discussed within the given length? Are the main ideas clear? Are they supported by the specific details in the examples? Do they move smoothly from one idea to the next? You’ll need enough time for a possible major overhaul, that is, you may have to make a lot of changes before your paper becomes really clear to the reader. So I’ll expect a preliminary draft of each paper two weeks before the final due date. That way I can criticize it and get it back in time for you to revise it. Then you can submit a final draft for grading. This process may seem like great deal of trouble at first, but I think you will find it valuable. In fact after you finish this course I doubt that you will ever turn in a term paper without first revising it carefully.

[ 本帖最后由 gjw 于 2008-8-25 15:45 编辑 ]

popcornwl

嘻嘻，，LZ加油哈

gjw

Our electric car is the way of the future. Automobile manufactures are under the pressure to develop cars that do not pollute. One powerful motive is a California law requiring that by the year 2000 10% of the new car sales in the state by so-called zero emission vehicles. These cars must put no pollutants whatsoever into the atmosphere. California is a huge market for the automobile companies. So they are working hard to meet these standards. So far the electric car seems to be the best alternative. So the biggest advantage of electric cars is that they don’t pollute. However they will be in competition with gas-powered cars. And that’s where the weaknesses come out. The big problem is that the batteries in electric cars weigh a lot relative to the amount of power they deliver. For instance in one electric car the batteries weigh four hundred kilograms and they provide enough energy to go 250 km before recharging, which take 8 hours. Compare that to a moderately fuel efficient conventional car it can go 400-700 km on a tank of gas. And refilling takes just minutes. If there are other drains on an electric car’s batteries besides a motor, headlight, air-conditioning or a heater, its already limited range would be significantly reduced. So automobile engineers are trying to make more powerful batteries that would increase the car’s range and make them more attractive to buyers.

[ 本帖最后由 gjw 于 2008-8-26 16:15 编辑 ]

gjw

Let’s turn our focus now to advertising, We all know what an advertisement is. It’s essentially a message that announces something for sale. Now there’s an important precondition that must exist before you have advertising, and that’s a large supply of consumer goods, that is, things to sell. You see in a place where the demand for a product is greater than the supply, there’s no need to advertise. Now the earliest forms of advertising going back many hundreds of years with a simple sign over shop doors that told you whether the shop was a bakery, a butcher shop or what have you. Then with the advent of the printing, advertising increased substantially. As for product like coffee, tea and chocolate appeared in newspapers and other periodicals, as well as on the sides of a building. In the American colonies, advertising and communication media like newspapers and pamphlets became a major factor in marketing goods and services. By modern standard, these early advertisements were quite small and subdued, not as splashy, whole page spread of today. Still some of them appeared on the front pages of newspapers probably because the news often consisted of less than refresh reports from distant Europe while the news were current and local. Advertising really came and do it so and became an essential part of doing business during the industrial revolution. Suddenly there was a much greater supply of things to sell. And as we said earlier, that is the driving force behind advertising. People’s attention had to be drawn to the new product. Let’s take a look at some of the advertisements from that time.

[ 本帖最后由 gjw 于 2008-8-26 16:27 编辑 ]

gjw

It is common knowledge that music can have a powerful effect on our emotions. In fact, since the 1930s, music therapists have relied on music to soothe patients and help control pain. Now psychologists are confirming that music can also help relive depression and improve concentration. For instance, in a recent study, 15 surgeons were given some highly stressed math problems to solve. They were divided into three groups: one group worked in silence, and in another, the surgeons listened to music of their choice on headphones; the third listened to classic music chosen by the researchers. The results of the study may surprise you. The doctors who got to choose their music experienced less stress and scored better than the others. One possible explanation is that listening to music you like stimulates the Alfa-wave in the brain increases the heart rate and expands breathing. That helps to reduce stress and sharpen concentration. Other research suggests a second relationship between the music and the brain: by examining the blood of students after they listen to a variety of classic music selections, the researchers found that some students showed a large increase in endorphin, a natural pain reliever, this supports what music therapists have known for years: music can help rejuvenate or soothe the patient.

[ 本帖最后由 gjw 于 2008-8-27 15:51 编辑 ]

gjw

Not long ago, some of you may have read about the team of mountain climbing scientists who helped to recalculate the elevation of the highest mountain in the world, Mount Everest. Of course the elevation of Mount Everest was determined many years ago using traditional surveying methods. But these scientists wanted to make a more precise measurement, using a new method that takes advantage of recent advances in technology; its called the Global Positioning System. The Global Positioning System uses 24 satellites that circle the earth. Each of the satellites is constantly sending out signals, and each signal contains important information that can be used to determine the longitude, latitude and elevation at any point on the earth’s surface. Well, in order to use this system to calculate Mount Everest’s elevation, scientists need to put a special receiver on its summit to receive signals from the satellite. The problem with this was that in the past, the receivers were much too heavy for climbers to carry. But now these receivers have been reduced to about the size and weight of a hand-held telephone, so climbers were able to take the receiver to the top of the Everest, and from there, to access the satellite system signals that would allow them to determine the precise elevation. And it turns out that the famous peak is actually a few feet higher than was previously thought.