Birds are literally half-asleep--with one brain hemisphere alert and the other sleeping, 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 (打盹) 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 32 percent of dozing time versus about 12 percent 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. lockout 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 (哺乳动物) 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 (冰山) ". He speculates that more examples may turn up when we take a closer look at other species.
A new study on birds' sleep has revealed that ______
A．half-brain sleep is found in all kinds of birds
B．half-brain sleep is characterized by accelerated brain waves
C．birds can control their half-brain sleep consciously
D．birds always sleep with the whole of their brain at rest
Did Grandma seem forgetful at the holiday parties last month？ It could be time to put her on a diet. Sharply【C1】______calories(卡路里)improves memory in older adults,according to a new study.
Research on the benefits of an extremely low-calorie diet【C2】______back to the 1930s, when scientists found that rats lived【C3】______to twice as long when they ate less than control animals. And how about in human？ To fill that【C4】______, scientist Agnes and her colleagues at the University of Muenster【C5】______50 healthy elderly subjects. The【C6】______volunteer was 60 years old and overweight. The researchers【C7】______assigned the volunteers to one of three groups. Twenty people were instructed to reduce their daily calorie【C8】______by 30%, while still eating a【C9】______diet. Another 20 were told to keep their calorie intake the same but increase their【C10】______of unsaturated(不饱和的 )fatty acids. The【C11】______10 volunteers did not change their diets.
After 3 months, all of the volunteers【C12】______a memory test in which they were shown 15 words and asked how many they could remember after 30 minutes.【C13】______average,those in the calorie-restriction group showed a 20%【C14】______over their baseline memory scores taken before they started their diets. Subjects in the other two groups showed【C15】______or no improvement. "Our study【C16】______provides some of the first【C17】______on the impact of calorie restriction on memory in the elderly, but this study has to be【C18】______up now," Floel noted. Her team plans to【C19】______larger studies to determine exactly【C20】______calorie restriction enhances memory.
【C1】
A．reducing
B．declining
C．burning
D．increasing
The future of business lies not in selling products but in selling dreams and emotions, according to Rolf Jensen, director of the Copenhagen Institute for Futures Studies. In his new book, The Dream Society, he profiles six distinct "emotional markets".
The Market for Adventures offers customers safaris, theme parks, sports, and action/ adventure TV shows and movies.
Nike's ties to the "Adventure" market made it willing to pay a reported ＄400 million simply for the right to sponsor Brazil's outstanding national soccer team, thereby boosting the brand's image as the footwear of champions. Such an investment makes sense in a market where consumers find many products with comparable features and quality and must find some reason to choose one over the others.
The Market for Love, Friendship, and Togetherness has such offerings as perfume, gifts, home photography, restaurants, and entertainment.
Tapping the "Togetherness" market, Guinness Brewery has teamed with an Irish firm to establish a chain for "authentic" Irish pubs in cities around the world--where Irish charm and British beer sell briskly in each other's company.
The Market for Care recently offered a product that captured children's desire to nurture and care for pets. The Tamagotchi is a demanding little electronic puppy that beeps for attention from its owner. Real pets are becoming hotel amenities in some places.
The Who-Am-I Market offers products that proclaim their owner's identity, like fashion, automobiles, and accessories.
Louis Vuitton suitcases, for instance, tell a story that their owners want to tell the world: "I am an exciting person, gliding with perfect ease through pos}t hotels all over the world, and I do it in style. ' Other consumers may want their purchases to proclaim their environmental awareness, so they may buy "bird friendly" coffee, grown only in shaded areas so endangered birds may be preserved. Eco-Sustainable Shady coffee and Caribou Coffee's Rainforest Blend are among several such offerings.
The Peace of Mind Market features nostalgia, history, and antiques.
In rapidly changing times, many people seek the serenity of the familiar, be it the bistros of Paris or small-town life in the US. For instance, First National Bank in Brookings, South Dakota, proclaims, "We strive to maintain the small-town banking atmosphere while growing and changing with the technological age. "
The Conviction Market, last of the six markets, includes "green" products, humane testing, and worker welfare.
While many companies may be reluctant to become overly political, they can highlight their involvement in the community and market to their customers' need to make purchase that are in line with their convictions. Among companies taking this approach are British Petroleum, which uses its Web site to report on the company's Community Development Programme, and Mobil, which accentuates its concern for local populations of countries in which it does business.
Jenson believes that companies will increasingly let consumers in on the story-telling process. Companies will come to value storytellers not only in their creative advertising departments, but in executive positions, where refashioning a company's history and traditions into an appealing myth will be crucial for winning the enthusiasm of employees, the affection of customers, and the respect of the general public. As the stories get better, sales should soar.
What may be Roll Jensen's main purpose of classifying these six distinct markets？
A．To classify different companies into corresponding market.
B．To invite businesses to consider how to best profit from them.
C．To set some models for companies in the market.
D．To predict trends in the market.
