In fact, they warn, drinking too much water could be, in certain cases, harmful.
In a study, Dr Stanly Goldfarb and Dr Dan Negoianu, both of the Renal, Electrolyte and Hypertension
Division at the University of Pensylvania, the United States, have denied the popular belief that drinking a lot
of water clears body toxins (毒素) better, improves skin, and helps reduce weight.
Dr Goldfarb and Dr Negoianu say that they found little proof to back the public opinion that drinking 8
glasses of water every day benefits health. At the same time, they fond little proof of harm in drinking 8
glasses of water every day.
It is widely believed that in some cases, such as athletes, people who live in hot, dry environments, and
those with certain medical conditions-drinking a lot of water indeed helps, but no studies have been done to
prove the benefits of this practice in average, healthy people, the website medheadlines.com reports.
The study at the University of Pennsylvania also examined reports that some people experienced increased
headaches when their consumption (消耗) of water was low. In one small study, which the doctors reviewed,
the group drinking the most water reported fewer headaches than the control group,"but the difference in the
number of headaches was so small between the two groups as to be considered unimportant."
The researchers concluded that there is no scientific proof to support that average, healthy people need to
drink at least 8 glasses of water each day. The website medheadlines.com says that, according to an Indian
doctor, drinking too much water is harmful. If water enters the body more quickly than it can be removed,
problems can occur.
B. Whether to drink enough water makes no difference.
C. Drinking too much water may cause headaches.
D. Average, healthy people should drink more water.
B. The Indian doctor.
C. The general public.
D. The website.
B. the study was carried out by two experts with an Indian doctor
C. the two experts performed the study at the University of Pennsylvania
D. drinking 8 glasses of water every day can cure certain diseases
learn, and many scientists are interested in finding ways to improve both teaching and learning processes.
Sian Beilock and Susan Leving, two psychologists at the University of Chicago, are trying to learn
about learning. In a new study about the way kids learn math in elementary school, Beilock and Levine
found a surprising relationship between what female teachers think and what female students learn: If a
female teacher is uncomfortable with her own math skills, then her female students are more likely to
believe that boys are better than girls at math."If these girls keep getting math-anxious female teachers in
later grades, it may create a snowball effect on their math achievement," Levine told Science News. The
study suggests that if these girls grow up believing that boys are better at math than girls are, then these
girls may not do as well as they would have if they were more confident.
Just as students find certain subjects to be difficult, teachers can find certain subjects to be difficult
to learn-and teach. The subject of math can be particularly difficult for everyone.
The new study involved 65 girls, 52 boys and 17 first-and second-grade teachers in elementary
schools in the Midwest. The students took math achievement tests at the beginning and end of the school
year, and the researchers compared the scores. The researchers also gave the students tests to tell whether
the students believed a math superstar had to be a boy. Then the researchers turned to the teachers: To
find out which teachers were anxious about math, the researchers asked the teachers how they felt at times
when they came across math, such as when reading a sales receipt. A teacher who got nervous looking at
the numbers on a sales receipt, for example, was probably anxious about math.
Boys, on average, were unaffected by a teacher"s anxiety. On average, girls with math-anxious teachers
scored lower on the end-of-the-year math tests than other girls in the study did. Plus, on the test showing
whether someone thought a math superstar had to be a boy, 20 girls showed feeling that boys would be
better at math-and all of these girls had been taught by female teachers with math anxiety.
According to surveys done before this one, college students who want to become elementary school
teachers have the highest levels of anxiety about math. Plus, nine of every 10 elementary teachers are
women, Levine said.
B. study students" ways of learning math
C. prove women teachers are unfit to teach math
D. find better teaching methods for teachers
B. study the ways their female teachers behave
C. have an influence on their math-anxious female teachers
D. gain unexpected achievement in such subjects as math
B. Tell their feelings about math problems.
C. Answer whether a math superstar had to be a boy.
D. Compare the students" scores after the math tests.
B. Almost all the girls got lower scores in the tests than the boys.
C. About 30% of the girls thought boys are better at math than girls.
D. Girls with math-anxious teachers all failed in the math tests.
B. The researchers felt surprised at the findings of their study.
C. Beilock and Levine are interested in teaching math.
D. Men teachers are better at teaching math than women teachers.
killing the seven astronauts on board in what NASA and President Bush called a tragedy for the entire nation.
NASA launched an investigation into the disaster and began searching for the astronauts" remains. It said that
although there had been some data failures it was too early to nail down a precise cause. The break-up, 16
minutes before the shuttle was due to land at Kennedy Space Center in Florida, spread possibly toxic debris
(有毒的残骸) over a wide area of Texas and neighboring states.
Dramatic television images of the shuttle"s descent clearly showed several white trails (痕迹) streaking
through blue skies after the shuttle suddenly fell apart. It was almost 17 years to the day that the Challenger
shuttle exploded on Jan. 28, 1986, killing all seven astronauts on board.
Take-off and re-entry into Earth"s atmosphere are the most dangerous parts of a space mission. In 42
years of US" human space flight, there had never been an accident in the descent to Earth or landing.
Challenger exploded just after take-off.
Rescue teams scrambled to search for the remains of the crew, which included the first Israeli to fly on
the shuttle, former combat pilot Col. Ilan Ramon. There were warnings that parts of a vast 120-mile-long
corridor of debris could be toxic because of poisonous rocket propellant (推进器).
"We are not ready to confirm that we have found any human remains," Nacogdoches County Sheriff
Thomas Kerrs said. He added that among the roughly 1,000 calls reporting debris, some people said they
found remains of crew members.
"The Columbia is lost. There are no survivors, …Their mission was almost complete and we lost them
so close to home. … America"s space program will go on," said a grim-faced Bush in a message broadcast
on television, which included condolences (同情) to the families of the dead astronauts.
B. landing
C. orbiting (绕轨运行)
D. walking down
B. He was the first foreign astronaut to fly on the American shuttle.
C. He used to be a passenger plane pilot.
D. He was the only survivor in the Columbia disaster.
B. both the shuttles exploded when they took off
C. Both the shuttles exploded when they were about to land
D. no human remains were found
B. NASA hasn"t found the cause of the Columbia disaster.
C. Before the Columbia disaster, no shuttles had exploded in the course of landing.
D. Take-off and re-entry into Earth"s atmosphere are the most dangerous parts of a space mission.
As an experienced photojournalist in Nashville, Tennessee, I was hired by USA Today newspaper to
photograph a spinal bifida (脊柱畸形) corrective surgical procedure. It was to be performed on a
twenty-one week old fetus (胎儿)in uterus (子宫)at Vanderbilt University Medical Center. At that time, in
1999, twenty-one weeks in uterus was the earliest that the surgical team would consider for surgery. The
worst possible outcome would be that the surgery would cause premature delivery, and no child born earlier
than twenty-three weeks had survived.
The tension could be felt in the operating room as the surgery began. A typical C-section incision (切口)
was made to access the uterus, which was then lifted out and laid at the junction of the mother"s thighs
(大腿). The entire procedure would take place within the uterus, and no part of the child was to breach the
surgical opening. During the procedure, the position of the fetus was adjusted by gently manipulating ( 熟练
操作) the outside of the uterus. The entire surgical procedure on the child was completed in one hour and
thirteen minutes. When it was over, the surgical team breathed a sigh of relief, as did I.
As a doctor asked me what speed of film I was using, out of the corner of my eye I saw the uterus
shake, but no one"s hands were near it. It was shaking from within. Suddenly, an entire arm thrust out of the
opening, then pulled back until just a little hand was showing. The doctor reached over and lifted the hand,
which reacted and squeezed the doctor"s finger. As if testing for strength, the doctor shook the tiny fist.
Samuel held firm. I took the picture! Wow! It happened so fast that the nurse standing next to me asked,
"What happened?" "The child reached out," I said. "Oh. They do that all the time," she responded.
The surgical opening to the uterus was closed and the uterus was then put back into the mother and
the C-section opening was closed.
It was ten days before I knew if the picture was even in focus. To ensure no digital manipulation of
images before they see them, USA Today requires that film be submitted (提交) unprocessed. When the
photo editor finally phoned me he said, "It"s the most incredible picture I"ve ever seen."
B. likely for a fetus born 21 weeks to become deformed (畸形的)
C. right time for a fetus born 21 weeks to receive an operation
D. risky for a fetus 21 weeks in uterus to receive an operation
B. demanding and unsuccessful
C. simple and short
D. long-lasting and difficult
B. the arm of the fetus
C. the taking of the picture
D. the head of the fetus
B. satisfied
C. annoyed
D. depressed
get going in the morning," she says. "I"d get depressed and gain 10 pounds every winter and lose them again
in the spring." Then she read about seasonal affective disorder, a form of depression that occurs in fall and
winter, and she saw the light literally. Every morning now she turns on a specially constructed light box for
half an hour and sits in front of it to trick her brain into thinking it"s still enjoying those long summer days. It
seems to work.
Krentz is not alone. Scientists estimate that 10 million Americans suffer from seasonal depression and 25
million more develop milder versions. But there"s never been definitive proof that treatment with very bright
lights makes a difference. After all, it"s hard to do a double-blind test when the subjects can see for themselves
whether or not the light is on. That"s why nobody has ever separated the real effects of light therapy from
placebo (安慰剂) effects.
Until now, in three separate studies published last month, researchers report not only that light therapy
works better than a placebo but that treatment is usually more effective in the early morning than in the
evening. In two of the groups, the placebo problem was resolved by telling patients they were comparing light
boxes to a new anti-depressant device that gives off negatively charged ions (离子). The third used the timing
of light therapy as the control.
Why does light therapy work? No one really knows."Our research suggests it has something to do with
shifting the body"s internal clock," says psychiatrist Dr. Lewey. The body is programmed to start the day with
sunrise, he explains, and this gets later as the days get shorter. But why such subtle shifts make some people
depressed and not others is a mystery.
That hasn"t stopped thousands of winter depressives from trying to heal themselves. Light boxes for that
purpose are available without a doctor"s prescription. That bothers psychologist Michael Terman of Columbia
University. He is worried that the boxes may be tried by patients who suffer from mental illness that can"t be
treated with light. Terman has developed a questionnaire to help determine whether expert care is needed.
In any event, you should choose a reputable manufacturer. Whatever product you use should give off only
visible light, because ultraviolet light damages the eyes. If you are photosensitive (对光敏感的), you may
develop a rash. Otherwise, the main drawback is having to sit in front of the light for 30 to 60 minutes in the
morning. That"s an inconvenience many winter depressives can live with.
B. Unexplained impairment of her nervous system.
C. Weakening of her eyesight with the setting in of winter.
D. Poor adjustment of her body clock to seasonal changes.
B. It serves as a kind of placebo.
C. It proves to be an effective therapy.
D. It hardly produces any effects.
B. No mental patients would bother to consult psychiatrists.
C. Bad light boxes will give off harmful ultraviolet lights.
D. Light therapy could be misused by certain mental patients.
B. Light therapy increases the patient"s photosensitivity.
C. Eye damage is a side effect of light therapy.
D. Light boxes can be programmed to correspond to shifts in the body clock.
Students and professionals can all benefit from reading scholarly research. While many works may be of
a technical nature, some of the best research is published in professional journals. While not all journals get
published on the Internet, the trend toward the electronic format is growing. You probably also have free
access to some of the online sources outlined below, but many don"t know where they can consult online
sources when in need of excellent research.
Science
The journal Science is perhaps the most prestigious science journal. This journal is also well known
enough to be featured on media outlets. It has all the latest news. Science is also interested in scientific policy,
and frequently publishes articles that report the achievement of technology and science in general. Free partial
access is available after registration.
Proceedings from the National Academy of Sciences (PNAS)
The world famous scholar reviewed journal has its articles and reviews on their website. While reading
the abstracts of articles is free, PNAS charges for downloading the entire article in full. There is also an option
for paying a flat rate to view several articles for a week-long period. There are some "open access" articles
which are available for download free of charge. Nature Nature is another popular and famous journal. Nature
has a wide approach publishing scientific papers on a wide variety of topics.
Nature in fact is considered interdisciplinary (各学科间的), going beyond its name which would seem to
show it only belongs to the natural sciences. Nature is aimed at researchers and academics, but readers can
find out about major breakthroughs through summaries and other notes that appear in this weekly publication.
While there is an effort to provide so-called "open access", it is at the moment limited. Students and those
with academic access can access these major journals for free because of contractual relationships.
B. Fewer and fewer journals will be put out online in the future.
C. Reading professional journals is quite helpful for students.
D. A small number of the online sources can be attained for free.
A. complicated
B. famous
C. special
D. instructive
B. the entire journal Nature
C. one article of the journal Science
D. "open access " PNAS articles
B. about a few academic magazines in the world
C. about free access to some of the online sources
D. which journal is most famous in the world
- 1下列关于经济全球化的说法错误的是[ ]A、经济全球化有助于世界各国经济、科技、文化的交往B、经济全球化对世界各国
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