night"s sleep.
Researchers from the University of Chicago asked volunteers to remember simple words . Many
found their memories letting them down towards the end of the day, but the following morning, those
who had slept well could recall much more.
Researchers, writing in the journal Nature, said the brain could "rescue" lost memories during the
night.
When the brain is first asked to remember something that memory is laid down in an "unstable" state,
meaning that it is possible that it could be lost . At some point, the brain consolidates those it deems
important into a "stable", more permanent state . However, the Chicago researchers suggested that it
was possible for a "stable" memory to be made "unstable" again . This would mean that memories
could be modified then filed away again in the face of new experiences.
The 12 volunteers tested in the experiment were played words created through a speech synthesizer
which were purposely difficult to understand . Initially, the written version of the word from the audio
version only . Tests revealed that the ability to recall the right word tended to tail off as the day ended.
However, when the volunteers were retested after a good night"s sleep, they were able to recall
some words that they had " forgotten" the previous evening.
Dr Daniel, one of the study authors, said: "Sleep consolidates memories, protecting them against
subsequent interference or decay . Sleep also appears to "recover" or restore memories." He said: "If
performance is reduced by decay, sleep might actively recover what has been lost."
Dr Karim Nader, from the Department of Psychology in McGill University in Montreal, said:
"Memory research is undergoing a transformation-no longer is memory thought to be a hard-writing
of the brain, instead it seems to be a process of storage and restorage."
Sleep helps some memories "mature" and also prunes out unimportant memories.
1. What does the first paragraph implies?
A . A busy day makes people forget things easily.
B . People need a good night"s sleep after a busy day.
C . A good night"s sleep helps memories.
D . A good night"s sleep helps people forget a busy day.
2 . The words the 12 volunteers played in the experiment were not ____
A . created through a speech synthesizer
B . hard to understand
C . available at the beginning
D . designed to test people"s ability of understanding
3 . According to the passage, memory_____
A . is a hard-writing of the brain
B . is not a process of storage
C . is not a process of restorage
D . will be mature with the help of sleep
4 . Which of the following is NOT true?
A . When people first remember something, the memory is in an "unstable state".
B . The brain will change those important unstable memories into stable.
C . Once the memory become stable, it will never become unstable again.
D . Sleep can protect memories from being harmed.
skiing in the snow-covered areas than sitting on the beach, according to a report by the UK newspaper
The Telegraph.
The researchers at Kanazawa Medical University, Japan and American company Johnson
Johnson conducted the study together. They looked at the effects of light reflection on newly fallen
snow on a ski trail (a rough path) in Ishikawa District, northern Japan. They compared the results with the
levels of UV rays on a sand beach in southern Japan"s Okinawa District.
They found that on the beach, eyes are exposed to a daily 260 kilojoules (千焦耳) of UV a square
meter compared to 658 kilojoules in snow-covered areas.
The findings are supported by the Japan Meteorological Agency. According to the agen- cy, the
reflection rate of UV light on beaches is often between 10 and 25 percent, compared to 80 percent in the
new snow areas. The amount of light increased 4 percent with a 300-meter rise in height.
Most of us know that UV rays can harm the skin. That"s why we wear sunscreen on our skin before we
get out in the sun. But many of us may not realize that UV rays are also harmful to the eyes.
If your eyes are exposed to large amounts of UV radiation over a short period of time, you may
experience a kind of sunburn of the eye, which is harmful. Your eyes will become red and feel a strange
feeling. They may be sensitive to light. Fortunately, this is usually temporary (暂时的) and seldom causes
permanent damage to the eyes.
Long-term exposure to UV radiation, however, can be more serious. Scientific studies and researches
have shown that exposure to small amounts of UV radiation over a period of many years increases the
chance of eye damage, which could lead to total blindness.
B. a travel journal
C. a medical magazine
D. a physics textbook
B. Short-time exposure of the eyes to UV rays doesn"t harm them at all.
C. Most people know that UV rays harm the eyes as well as the skin.
D. The study was conducted by researchers from Japan, the USA and the UK.
B. sunhat
C. suncream
D. sunburn
B. Go to hospital to have your eyes examined.
C. Wearing a hat can provide protection while skiing in new snow areas.
D. Take some measures to protect your eyes while skiing in new snow areas.
Manned submersibles (潜水器), like spaceships, must maintain living conditions in an unnatural
environment. While a spaceship must simply be sealed against the vacuum space, a submersible must be
able to bear extreme pressure if it is not to break up in deep water.
In exploring space, unmanned vehicles were employed before astronauts. In undersea exploration, on
the other hand, men paved the way, and only recently have unmanned remote-operated vehicles (ROVs)
been put to use.
One reason for this is that communicating with vehicles in orbit is much easier than talking to those
underwater. A vacuum is an ideal medium for radio communications, but underwater communications are
limited to much slower sound waves. Thus, most undersea vehicles - particularly ROVs - operate at the
end of long ropes.(电缆终端)
For a similar reason, knowing where you are undersea is much more difficult than in space. A
spaceship"s position can be located by following its radio signal, or by using telescopes and radar. For an
undersea vehicle, however, a special network of sonar (声纳系统) devices must be laid out in advance on the ocean floor in the area of a dive to locate the vehicle"s position.
Though undersea exploration is more challenging than outer space in a number of respects, it has a
distinct advantage: going to the ocean depths doesn"t require the power necessary to escape Earth"s
gravity. Thus, it remains far less expensive.
B. to stress the importance of the undersea exploration
C. to make you believe that the undersea exploration is better
D. to tell some differences between two kinds of explorations
B. men covered the ocean floor with stones and bricks
C. manned vehicles were employed before unmanned ones
D. men invented unmanned remote-operated vehicles in the past
B. after the undersea vehicles dive
C. before the undersea vehicles dive
D. when the undersea vehicles are diving
B. Undersea vehicles can receive signals immediately.
C. Going to space needs power to escape the gravity.
D. Radio communications are quite difficult in a vacuum.
Birds that are half-asleep-with one brain hemisphere (半球) 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 groups led researchers to predict extra alertness in the end-of-the-row
sleepers which tend to be attacked more easily. 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 napping at the end of the line depend on single-hemisphere sleep, rather than total relaxation, more often than inner ducks did. Turning 16 birds through the positions in a four-duck row, the
researchers found that compared with 12 percent for birds in internal spots, outer birds half-asleep during some 32 percent of napping time.
"We believe this is the first evidence for an animal behaviorally controlling sleep and wakefulness at the
same time in different regions of the brain," the researchers say.
The results provide the best evidence for a long-standing assumption 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 napping 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 animals 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 supposes that more examples may turn up
when we take a closer look at other species.
1. According to the passage, birds often half sleep because ______.
A. they have to watch out for possible attacks
B. their brain hemispheres take turns to rest
C. the two halves of their brain are differently structured
D. they have to constantly keep an eye on their companions
2. What is implied about the example of a bird"s sleeping in front of a mirror?
A. An imagined companion gives the bird a sense of security.
B. Birds prefer to sleep in pairs for the sake of their security.
C. The phenomenon of birds napping in pairs is widespread.
D. A single pet bird enjoys seeing its own reflection in the mirror.
3. While sleeping, some water animals tend to keep half awake in order to ______.
A. alert themselves to the approaching enemy
B. emerge from water now and then to breathe
C. be sensitive to the ever-changing environment
D. avoid being swept away by rapid currents
4. By saying "just the tip of the iceberg", Siegel suggests that ______.
A. half-brain sleep has something to do with icy weather
B. the mystery of half-brain sleep is close to being solved
C. most birds living in cold regions tend to be half sleepers
D. half-brain sleep may exist among other species
Studying for an exam while listening to music is not smart, because background music can injure
your ability to perform memory tasks, new research has found.
Study participants were asked to recall a list of eight consonants (辅音字母) in the order they
were presented. They did this while in five different sound environments: quiet surroundings; music
they liked music they disliked; changing state; and steady state.
The participants recall ability was poorest when listening to music, regardless of whether
they liked or disliked it, and in changing-state conditions. The most accurate recall occurred
when participants performed the task in steady-state environments, according to the study
published online in the journal Applied Cognitive Psychology.
The poorer performance of the music and changing-state sounds are due to the audible (听得
见的) change within those environments. This hurts the ability to recall the order of items, via retelling,
within the presented list, explained lead researcher Nick Perham, a lecturer in the School of Psychology
at the University of Wales Institute in Cardiff, in a news release from the journal"s publisher.
"Mental arithmetic (算术) also requires the ability to memorize order information in the short-term
via retelling, and may be similarly affected by their performance in the presence of changing-state,
background environments," he added.
B. in the music you dislike
C. in changing state
D. in steady state
B. they got lost in the music
C. the changeable sound disturb the input of the information
D. they couldn"t focus their attention
B. 33333.
C. abcde.
D. a1b2c.
B. Music may affect our performance of memorizing
C. Mental arithmetic means retelling the order of information
D. Reading in the noisy street can strengthen our ability of concentrating
together in 2009, even though many of them never had an opportunity to meet during their high school
days.
Schools in the 1950"s, like most other public locations, were segregated (隔离)in Georgia. Kids were
forced to attend different schools depending on the color of their skin, and those with white skin were
further separated by gender. Fifty years later these people who were not allowed to associate with each
other were finally able to connect.
It all began with the personal journey of a man named Tom Johnson. He grew up in Macon and
enjoyed a very successful career which included serving as the publisher of the Los Angeles Times and
president of CNN. Tom"s life changed drastically over the years, but he still felt the desire to reconnect
with his roots.
In 2005 Johnson returned to Macon with his son, Wyatt. As the pair drove around town, the father
recounted high school stories to his son. He talked about how students attended one of three schools:
BallardHudson, Lanier or Miller. Wyatt looked over at his father and said: "Dad think about how
many friends you missed getting to know."
Johnson thought about the people he never got the chance to meet. He decided to do something
about it.
The first step was to find people who graduated from all three schools. Johnson wrote to each person
and proposed they all get together for a luncheon. He explained that even though they were kept apart
during their youth, they didn"t have to be separated any more. His classmates received the message with
open hearts. A reunion date was set for October.
More than 200 former Macon students traveled hundreds of miles to reunite with people who went
to high school with them. It was an unprecedented event, former students coming together to make up
for the time they had lost during the days of segregation.
B. attend school of mixed sexes
C. attend school with students of other skin colors
D. attend any school they like
B. were doubtful about his real purpose
C. refused to listen to him
D. all began to miss him
B. wanted to reconnect with his roots after the dramatic changes in his life
C. wanted to reconnect with his roots in spite of his successful career
D. began to miss his old school friends after hearing his son"s words
B. the segregation in Georgia in the 1950"s
C. an unusual reunion of old graduates
D. the old school system in Georgia
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