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 hemispheres eye stays open and alert. Birds also can sleep with both hemispheres resting at once.
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 hemispheres 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. Rotaing 16 birds through the positions in a four-duck row, the researchers found outer birds half-asleep during some 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 lookout side could be widespread, he predicts. Hes seen it in a pair of birds dozing side-by-side in the zoo and in a single pet bird sleeping by 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, its 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 UGLA 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.
16. Which of the following is evidence that TT is widely practiced?
A) TT has been in existence for decades.
B) Many patients were cured by therapeutic touch.
C) TT therapists are often employed by leading hospitals.
D) More than 100,000 people are undergoing TT treatment.
注：D为迷惑选项数字必转化，C对应第二段末句。
17. Very few TT practitioners responded to the $1 million offer because ____________.
A) they didnt take the offer seriously
B) they didnt want to risk their career
C) they were unwilling to reveal their secret
D) they thought it was not in line with their practice
注：争议题，B、C皆可。
18. The purpose of Emily Rosas experiment was ____________.
A) to see why TT could work the way it did
B) to find out how TT cured patients illness
C) to test whether she could sense the human energy field
D) to test whether a human energy field really existed
注：对应文章第三段首句
19. Why did some TT practitioners agree to be the subjects of Emilys experiment?
A) It involved nothing more than mere guessing.
B) They thought it was going to be a lot of fun.
C) It was more straightforward than other experiments.
D) They sensed no harm in a little girls experiment.
注：对应文章第三段末句，no harm对应innocent，little girl对应fourth-grade
20. What can we learn from the passage?
A) Some widely accepted beliefs can be deceiving.
B) Solid evidence weighs more than pure theories.
C) Little children can be as clever as trained TT practitioners.
D) The principle of TT is too profound to understand.
A nine-year-old schoolgirl single-handedly cooks up a science-fair experiment that ends up debunking(揭穿...的真相)a widely practiced medical treatment. Emily Rosas target was a practice known as therapeutic(治疗)touch , whose advocates manipulate patients energy field to make them feel better and even, say some, to cure them of various ills. Yet Emilys test shows that these energy fields cant be detected, even by trained TT practitioners(行医者). Obviously mindful of the publicity value of the situation, Journal editor George Lundberg appeared on TV to declare, Age doesnt matter. Its good science that matters, and this is good science.
Emilys mother Linda Rosa, a registered nurse, has been campaigning against TT for nearly a decade. Linda first thought about TT in the late 80s, when she learned it was on the approved list for continuing nursing education in Colorado. Its 100,000 trained practitioners dont even touch their patients. Instead, they waved their hands a few inches from the patients body, pushing energy fields around until theyre in balance. TT advocates say these manipulations can help heal wounds, relieve pain and reduce fever. The claims are taken seriously enough that TT therapists are frequently hired by leading hospitals, at up to $70 an hour, the smooth patients energy, sometimes during surgery.
Yet Rosa could not find any evidence that it works. To provide such proof, TT therapists would have to sit down for independent testing-something they havent been eager to do, even though James Randi has offered more than $1 million to anyone who can demonstrate the existence of a human energy field. A skeptic might conclude that TT practitioners are afraid to lay their beliefs on the line. But who could turn down an innocent fourth-grader? Says Emily: I think they didnt take me very seriously because Im a kid.
The experiment was straightforward: 21 TT therapists stuck their hands, palms up, through a screen. Emily held her own hand over one of theirs-left or right-and the practitioners had to say which hand it was. When the results were recorded, theyd done no better than they would have by simply guessing. if there was an energy field, they couldnt feel it.
21. We learn from the first paragraph that two systems of automated highways __________.
A) are being planned
B) are being modified
C) are now in wide use
D) are under construction
注：on the drawing borad就是planned
22. A special-purpose lane system is probably advantageous in that ________________.
A) it would require only minor changes to existing highways
B) it would achieve the greatest highway traffic efficiency
C) it has a lane for both automated and partially automated vehicles
D) it offers more lanes for automated vehicles
注：A选项说反了
23. Which of the following is true about driving on an automated highway?
A) Vehicles traveling on it are assigned different lanes according to their destinations.
B) A car can join existing traffic any time in a mixed lane system.
C) The driver should inform his car computer of his destination before driving onto it.
D) The driver should share the automated lane with those f regular vehicles.
注：对应第二段开头
24. We know form the passage that a car can enter a special-purpose lane _____________.
A) by smoothly merging with cars on the conventional lane
B) by way of a ramp with electronic control devices
C) through a specially guarded gate
D) after all trespassers are identified and removed
注：争议题
25. When driving in an automated lane, the driver ___________.
A) should harmonize with newly entering cars
B) doesnt have to rely on his computer system
C) should watch out for potential accidents
D) doesnt have to hold not to the steering wheel
注：文章最后一段