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
时间：2023-01-16 12:22:49
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Oracle9i extends the cursor sharing functionality with the new value of SIMILAR for the CURSOR_SHARING parameter. With CURSOR_SHARING = SIMILAR， cursors are shared for safe literals only. What is meant by ‘safe literals only’？（）
A . No literal value is substituted for a shared cursor.
B . Different execution plans are generated for substituted literal values.
C . The substitution of a literal value will produce different execution plans.
D . The substitution of any literal value will produce exactly the same execution plan.
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Two birds escaped （） their cage.
A . from
B . with
C . out
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The day breaks, __________ the birds are singing.
A . because
B . as
C . since
D . for
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Literal education; General-knowledge education
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Kill two birds with one stone. 下列译文中正确的有( )
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Pigs cannot fly, so they are not birds. Indicate which of the following is a single suppressed premise that is sufficient to make this argument valid.
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Symbols in fiction are images, objects, settings, events, and characters that convey meaning beyond their literal significance.
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The author uses the example of Angry Birds to illustrate that many game apps on smartphones are both entertaining and educational.
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“ 桃李满天下 ” literally means “plum trees and the peach trees are everywhere.”“ 桃李 ” here refers to students.
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They wrotetales of princess and magic birds.
A. plays
B. legends
C. stories
D. novels
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Fred bought some small birds to wake them up.
A．Right.
B．Wrong.
C．Doesn't say.
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Which of the following words is used metaphorically, NOT literally？
A．Gripped(Paragraph One).
B．Melting(Paragraph Two).
C．Trigger(Paragraph Two).
D．Dropped(Paragraph Three).
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Some species of birds are highly sociable and nest in dense colonies.
A．hardly
B．seasonably
C．extremely
D．chiefly
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【C1】______ nearly a hundred years of powered flight, scientists are still trying to figure out how birds fly.
Researchers have learned that the slapping noise pigeons make when they suddenly take off is the sound of super charged lift. They call it the "clap fling" effect.
Here at SRI International scientists try to duplicate the pigeons' thrust. A flashing strobe reveals the secret.
Scott Stanford, a scientist at SRI, says, You re looking at the clap fling effect, where the two wings will come together and peel apart 【C2】______ each other, thus augmenting lift 【C3】______ drawing air from the top to the bottom. "
This mechanical bug won't get off the ground. 【C4】______ its flapping wings demonstrate a potential propulsion system for robotic birds: man-made rubbery muscle.
Roy Kornbluh works at SRI. "There, I'm turning the voltage on and off, and you can see when the voltage is on, the material is larger 【C5】______ when the voltage is off."
Super computers show high-speed airflows over supersonic aircraft.
But scientists have only begun to see how air flows 【C6】______ really low speeds.
Professor Max Platzer of the Naval Postgraduate School, says, "The flapping wing is generating a thrust, this way, this is the basic physics of the phenomenon."
It's pelicans--not pigeons--the Navy is looking at. The Navy is looking at the smooth easy flight of pelicans low over water--called "ground effect." Researchers at the Naval Postgraduate School are trying to imitate the pelican's efficiency.
Assistant Professor Kevin Jones of the Naval Postgraduate School says, " 【C7】______ flapping the wings, symmetrically, we're 【C8】______ effect imitating ground effect. We now have the same feature a bird sees when it's flying, over a ground plane."
An electric motor drives the flapping wings. Researchers here are working 【C9】______ ways to beam power to the tiny bird.
David Jenn of the Naval Postgraduate School says, "There's no battery inside of here, so we're going to set this inside the radar beam, and the energy is extracted from the radar beam and will be used to propel the motor."
Scientists are learning it's one thing to build an airplane, 【C10】______ quite another to build a bird.
【C1】______
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I'm afraid there are people in the world who literally do not know how to boil water.
A．liberally
B．actually
C．theoretically
D．solely
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What do the fishermen do to encourage the birds？
A．They use a long string to beat the birds.
B．They give the birds some fish to encourage the birds.
C．They beat the sides of the boat to stimulate the birds.
D．They grasp several birds in one hand.
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“直译” 可翻译为 literal translation
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A pet is an animal that【21】in your house. Over half the families in North America own pets. The most popular【22】axe dogs, fish and birds. Rabbits, hamsters and turtles are also popular.【23】some unpopular animals such as frogs, mice and snakes are pets.
People first【24】to keep pets about 12,000 years ago. The first pet was a dog. The dog【25】not become a pet because people【26】it was cute. It【27】a pet because it was useful. People used the dog for many things. The dog warned people【28】danger so wild animals didn't attack people. It also ate leftover food. Later, dogs helped people take care【29】cows and sheep on farms.
Cats did not【30】pets for a long time. When the Egyptians first【31】to grow grain, mice ate it. The Egyptians were【32】to tame cats.
Today, people keep many【33】of pets. Animals such as canaries, parrots, mice and hamsters live in cages. They need people to bring them food and water and to keep their cages clean. Other animals, such as dogs and cats, need food and water, but they【34】take care of themselves【35】. They are good pets for people because they don't need much care.
(36)
A．lives
B．stays
C．sleeps
D．plays
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The lady didn't like all kinds of birds.
A．Right.
B．Wrong.
C．Doesn't say.
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We know that many animals de not stay in one place. Birds, fish and other animals move from one place to another at a certain time. They move for different reasons: most of them move to find food more easily, but others move to get away from places that are too crowded.
When cold weather comes, many birds move to warmer places to find food. Some fishes give birth in warm water and move to cold water to feed. The most famous migration (迁移) is probably the migration of fish, which is called "salmon". This fish is born in fresh water but it travels many miles to salt water. There it spends its life. When it is old, it returns to its birthplace in fresh water. Then it gives birth and dies there. In northern Europe, there is a kind of mouse. They leave their mountain homes when they become too crowded. They move down to the low land. Sometimes they move all the way to the seaside, and many of them are killed when they fall into the sea.
Recently, scientists have studied the migration of a kind of lobster (龙虾). Every year, when the season of bad weather arrives, the lobsters get into a long line and start to walk across, the floor of the ocean. Nobody knows why they do this, and nobody knows where they go.
So, sometimes we know why humans and animals move from one place to another, but at other times we don't. Maybe living things just like to travel.
Most animals move from one place to another at a certain time to ______.
A．give birth
B．enjoy warmer weather
C．find food more easily
D．find beautiful places
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Scientists have established that influenza viruses taken from man can cause the disease in animals. In addition, man can catch the disease from animals. In fact, a great number of wild birds seem to carry the virus without showing an evidence of illness. Some scientists concluded that a large family of influenza viruses may have evolved in the bird kingdom, a group that has been on the earth 100 million years and is able to carry the virus without contracting the disease. There is even convincing evidence to show that virus strains are transmitted from place to place and from continent to continent by migrating birds.
It's known that two influenza viruses can recombine when both are present in an animal at the same time, the result of such recombination is a great variety of strains containing different H and N spikes. This raises the possibility that a human influenza virus can recombine with an influenza virus from a low animal to produce an entirely new spike. Research is underway to determine if that is the way that major new strains come into being, another possibility is that two animal influenza strains may recombine in a pig, for example, to produce a new strain which is transmitted to man.
According to the passage, scientists have discovered that influenza viruses ______.
A．cause ill health in wild birds
B．do not always cause symptoms in birds
C．are rarely present in wild birds
D．change when transferred from animals to man
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A.I literally can’t stop.
B.But now I don’t need to worry any more.
C.You’re known as the first billionaire author here.
D.But that’s not just about money.
Interviewer: You have published six popular books. 7___________
Interviewee: Yeah.
Interviewer: So how has being the first billionaire author affected your perception of yourself？
Interviewee: I dress better. Well, you can definitely afford better clothes. 8___________I think the single biggest thing that money gave me--and obviously I came from a place where I was a single mother and it really was hand to mouth at one point. It was literally as poor as you can get without being homeless at one point. 9___________ Never.
Interviewer: Are you in a place now where you can accept that you will always be rich？
Interviewee: No.
Interviewer: And will you be writing more？
Interviewee: Oh, definitely. I can’t, yeah, 10___________ Well, I mean, you could tie my hands to my sides, I suppose, but I have to write. For my own mental health, I need to write.
7、___________
8___________
9___________
10___________
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Environmentalists are doing everything within their power to protect the birds and ___
A．A.minimize
B．B.swallow
C．C.exaggerate
D．D.abridge
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· Problems： （1） The number of birds is becoming ____
