快速导航
学历类
职业资格
公务员
医卫类
建筑工程
外语类
外贸类
计算机类
财会类
技能鉴定
Don't wash those fossils!
Standard museum practice can wash away DNA.
1.Washing, brushing and varnishing fossils — all standard conservation
treatments used by many fossil hunters and museum curators alike — vastly
reduces the chances of recovering ancient DNA.
2.Instead, excavators should be handling at least some of their bounty with
gloves, and freezing samples as they are found, dirt and all, concludes a paper
in the Proceedings of the National Academy of Sciences today.
3.Although many palaeontologists know anecdotally that this is the best way
to up the odds of extracting good DNA, Eva-Maria Geigl of the Jacques Monod
Institute in Paris, France, and her colleagues have now shown just how important
conservation practices can be.This information, they say, needs to be hammered
home among the people who are actually out in the field digging up bones.
4.Geigl and her colleagues looked at 3,200-year-old fossil bones belonging to
a single individual of an extinct cattle species, called an aurochs.The fossils
were dug up at a site in France at two different times — either in 1947, and
stored in a museum collection, or in 2004, and conserved in sterile conditions
at -20 oC.
5.The team's attempts to extract DNA from the 1947 bones all failed.The newly
excavated fossils, however, all yielded DNA.
6.Because the bones had been buried for the same amount of time, and in the
same conditions, the conservation method had to be to blame says Geigl."As much
DNA was degraded in these 57 years as in the 3,200 years before," she says.
Wash in, wash out
7.Because many palaeontologists base their work on the shape of fossils
alone, their methods of conservation are not designed to preserve DNA, Geigl
explains.
8.The biggest problem is how they are cleaned.Fossils are often washed
together on-site in a large bath, which can allow water — and contaminants in
the form of contemporary DNA — to permeate into the porous bones."Not only is
the authentic DNA getting washed out, but contamination is getting washed in,"
says Geigl.
9.Most ancient DNA specialists know this already, says Hendrik Poinar, an
evolutionary geneticist at McMaster University in Ontario, Canada.But that
doesn't mean that best practice has become widespread among those who actually
find the fossils.
10.Getting hold of fossils that have been preserved with their DNA in mind
relies on close relationships between lab-based geneticists and the excavators,
says palaeogeneticist Svante P bo of the Max Planck Institute for Evolutionary
Anthropology in Leipzig, Germany.And that only occurs in exceptional cases, he
says.
11.P bo's team, which has been sequencing Neanderthal DNA, continually faces
these problems."When you want to study ancient human and Neanderthal remains,
there's a big issue of contamination with contemporary human DNA," he says.
12.This doesn't mean that all museum specimens are fatally flawed, notes P
bo.The Neanderthal fossils that were recently sequenced in his own lab, for
example, had been part of a museum collection treated in the traditional way.But
P bo is keen to see samples of fossils from every major find preserved in line
with Geigl's recommendations — just in case.
Warm and wet
13.Geigl herself believes that, with cooperation between bench and field
researchers, preserving fossils properly could open up avenues of discovery that
have long been assumed closed.
14.Much human cultural development took place in temperate regions.DNA does
not survive well in warm environments in the first place, and can vanish when
fossils are washed and treated.For this reason, Geigl says, most ancient DNA
studies have been done on permafrost samples, such as the woolly mammoth, or on
remains sheltered from the elements in cold caves — including cave bear and
Neanderthal fossils.
15.Better conservation methods, and a focus on fresh fossils, could boost DNA
extraction from more delicate specimens, says Geigl.And that could shed more
light on the story of human evolution.
(640 words nature )
Glossary
Palaeontologists 古生物学家
Aurochs 欧洲野牛
Neanderthal (人类学)尼安德特人，旧石器时代的古人类。
Permafrost (地理)永冻层
Questions 1-6
Answer the following questions by using NO MORE THAN THREE WORDS for each
answer.
1.How did people traditionally treat fossils?
2.What suggestions do Geigl and her colleagues give on what should be done
when fossils are found?
3.What problems may be posed if fossil bones are washed on-site? Name
ONE.
4.What characteristic do fossil bones have to make them susceptible to be
contaminated with contemporary DNA when they are washed?
5.What could be better understood when conservation treatments are
improved?
6.The passage mentioned several animal species studied by researchers.How
many of them are mentioned?
Questions 7-11
Do the following statements agree with the information given in the passage?
Please write TRUE if the statement agrees with the writer FALSE if the statement
does not agree with the writer NOT GIVEN if there is no information about this
in the passage.
7.In their paper published in the Proceedings of the National Academy of
Sciences，Geigl and her colleagues have shown what conservation practices should
be followed to preserve ancient DNA.
8.The fossil bones that Geigl and her colleagues studied are all from the
same aurochs.
9.Geneticists don't have to work on site.
10.Only newly excavated fossil bones using new conservation methods suggested
by Geigl and her colleagues contain ancient DNA.
11.Paabo is still worried about the potential problems caused by treatments
of fossils in traditional way.
Questions 12-13
Complete the following the statements by choosing letter A-D for each
answer.
12.“This information” in paragraph 3 indicates:
[A] It is critical to follow proper practices in preserving ancient DNA.
[B] The best way of getting good DNA is to handle fossils with gloves.
[C] Fossil hunters should wear home-made hammers while digging up bones.
[D] Many palaeontologists know how one should do in treating fossils.
13.The study conducted by Geigl and her colleagues suggests:
[A] the fact that ancient DNA can not be recovered from fossil bones
excavated in the past.
[B] the correlation between the amount of burying time and that of the
recovered DNA.
[C] the pace at which DNA degrades.
[D] the correlation between conservation practices and degradation of
DNA.
Asian economies will continue to expand rapidly in the next two years on the
back of foreign investments, exports and domestic demand, but will not be free
of worries, according to a recent securities company economic report. Massive
infrastructure spending, the benefits of past investments and deregulation and
growing regional trade will push along regional growth.
The report tipped China’s gross domestic product to grow by 9.5 per cent in
1996 and 10.5 per cent in 1997, and Hong Kong’s to grow by 4.3 and 5.0 per cent.
Singapore’s real GDP was forecast to grow by 7.6 and 7.4 per cent, Malaysia’s by
8.6 and 8.1 per cent, Thailand’s by 8.8 and 8.4 per cent, Indonesia’s by 7.3 and
7.1 per cent and Philippines’ by 5.6 and 5.8 per cent.
“However, all is not rosy,” cautioned the report, which listed overheating as
the region’s biggest challenge in the short term and skilled-labor shortages in
the long run.
It cited strains from rapid growth that had begun to stretch current account
deficits and spur inflation in some regional economies, which could prevent
their central banks from lowering interest rates.
“This implies that economic vulnerability to unexpected shocks will remain
high,” the report said, forecasting a further tightening of monetary policy in
countries such as the Philippines and Malaysia, and no significant easing in
Thailand, Indonesia and China.
Crosby Securities also cited massive new investment programs generated by
demands on infrastructure such as power, telecommunications and transport which
had fuelled over-heating.
It said Asia would also face a bigger challenge from newly deregulating
economies in Eastern Europe which offered lower costs and better-educated
workers to foreign investors.
Asia’s main foreign investors should, however, continue to expand their
presence in the region, the securities house said, noting new trends of
intra-Asian investment.
Singapore is shifting its lower value-added disc drive and electronics
industry to Malaysia, which in turn is moving some of its garment-making and
consumer electronics manufacturing to Indonesia and Thailand. Thailand, Malaysia
and Singapore are increasingly investing in Viet Nam, Myanmar and Laos.
“Asia will benefit from this trend in several ways,” the report said.
( )1Asia economy will continue to grow because of _____________.
A. foreign investment B. demands in Asian countries.
C. export D. all of the above
( )2 In the next 2 years, the highest economic growth will appear in
____________.
A. Singapore B. Thailand
C. Hong Kong D. China
( )3 Years later, the problem in Asian economy may be _________________.
A. too little investment B. too much investment
C. not enough qualified labors D. monetary instability
( )4 According to this report, economic changes in East Europe are
___________.
A. harmful B. challenging
C. helpful D. useless
( )5 The report is about the prospect of Asian economy.
A. optimistic B. pessimistic
C. more optimistic than pessimistic D. more pessimistic than optimistic
Without regular supplies of some hormones our capacity to behave would be seriously impaired; without others we would soon die. Tiny amounts of some hormones can modify moods and actions, our inclination to eat or drink, our aggressiveness or submissiveness, and our reproductive and parental behavior. And hormones do more than influence adult behavior; early in life they help to determine the development of bodily form and may even determine an individual’s behavioral capacities. Later in life the changing outputs of some endocrine glands and the body’s changing sensitivity to some hormones are essential aspects of the phenomena of aging.
Communication within the body and the consequent integration of behavior were considered the exclusive province of the nervous system up to the beginning of the present century. The emergence of endocrinology as a separate discipline can probably be traced to the experiments of Bayliss and Starling on the hormone secretion. This substance is secreted from cells in the intestinal walls when food enters the stomach; it travels through the bloodstream and stimulates the pancreas to liberate pancreatic juice, which aids in digestion. By showing that special cells secret chemical agents that are conveyed by the bloodstream and regulate distant target organs or tissues. Bayliss and starling demonstrated that chemical integration could occur without participation of the nervous system.
The term “hormone” was first used with reference to secretion. Starling derived the term from the Greek hormone, meaning “to excite or set in motion. The term “endocrine” was introduced shortly thereafter “Endocrine” is used to refer to glands that secret products into the bloodstream. The term “endocrine” contrasts with “exocrine”, which is applied to glands that secret their products though ducts to the site of action. Examples of exocrine glands are the tear glands, the sweat glands, and the pancreas, which secrets pancreatic juice through a duct into the intestine. Exocrine glands are also called duct glands, while endocrine glands are called ductless.
1.What is the author’s main purpose in the passage?
A.To explain the specific functions of various hormones.
B.To provide general information about hormones.
C.To explain how the term “hormone” evolved.
D.To report on experiments in endocrinology.
2.The passage supports which of the following conclusions?
A.The human body requires large amounts of most hormones.
B.Synthetic hormones can replace a person’s natural supply of hormones if
necessary.
C.The quantity of hormones produced and their effects on the body are related
to a person’s age.
D.The short child of tall parents very likely had a hormone deficiency early
in life.
3.It can be inferred from the passage that before the Bayliss and Starling
experiments, most people believed that chemical integration occurred
only___.
A.during sleep.
B.in the endocrine glands.
C.under control of the nervous system.
D.during strenuous exercise.
4.The word “liberate” could best be replaced by which of the following?
A.Emancipate B.Discharge C.Surrender D.Save
5.According to the passage another term for exocrine glands is___.
A.duct glands
B.endocrine glands
C.ductless glands
D.intestinal glands.
Passage 2
Questions 6 to 10 are based on the following passage:
The food we eat seems to have profound effects on our health. Although science has made enormous steps in making food more fit to eat, it has, at the same time, made many foods unfit to eat. Some research has shown tat 40 percent of cancer is related to the diet as well, especially cancer of the colon.
Different cultures ate more prone to get certain illnesses because of the food that is characteristic in these cultures. That food is related to illness is not a new discovery. In 1945, government researchers realized that nitrates and nitrites, commonly used to preserve color in meats, and other food additives,
caused cancer. Yet these carcinogenic additives remain in our food, and it becomes more difficult all the time to know which things on the packaging labels of processed food are helpful or harmful. The additives that we eat are not all so direct. Farmers often give penicillin to beef and poultry, and because of
this, penicillin has been found in the milk of treated cows. Sometimes similar drugs are administered to animals not for medicinal purposes, but for financial reasons. The farmers are simply trying to fatten the animals in order to obtain a higher price on the market. Although the Food and Drug Administration (FDA) has tried repeatedly to control these procedures, the practices continue.
6. How has science done a disservice to mankind?
A. Because of science, most of the foods we eat today are contaminated.
B. It has caused a lack of information concerning the value of food.
C. As a result of scientific intervention, some potentially harmful
substances has been added to our food.
D. The scientists have preserved the color of meats, but not of
vegetables.
7. What are nitrates used for?
A. They preserves flavor in packaged foods.
B. They preserve the color of meats.
C. They are the objects of research.
D. They cause the animals to become fatter.
8. The FDA has tried repeatedly to control .
A. the attempt to fatten the animals
B. the attempt to cure sick animals
C. the using of drugs to animals
D. the using of additives to preserve the dolor of food
9. The word “carcinogenic” means most nearly the same as .
A. trouble-making B. color-retaining
C. money-saving D. cancer-causing
10. Which of the following statements is NOT true?
A. Drugs are always given to animals for medical reasons.
B. Some of the additives in our food are added to the food itself and some
are given to the living animals.
C. Researchers have known about the potential hazards of the food additives
for over thirty-five years.
D. Food may cause forty percent of cancer in the world.
Section D
Even if you get work done and generally get along with co-workers, you could
have habits that bug your boss (not to mention your officemates). While these
quirks may not necessarily get you fired, they certainly can keep you from
climbing the corporate ladder. We’ve uncovered a number of habits that bug your
boss and offer tips on how to avoid them.
According to LaRhonda Edwards, a human resources manager with thirteen years
of HR experience, tardiness is one of the biggest concerns for managers. “If the
normal work day starts at 8 o’clock, then the expectation is that you’re in the
office ready to start your day,” she explains. Her advice to the chronically
late? “Plan ahead,” she urges. “If you live 50 minutes away, you don’t leave 50
minutes early. Tag on extra time and anticipate road blocks.” Some people even
set their clocks a few minutes early to ensure that they’re on time. Different
bosses prefer different modes of communication. Lindsey Pollak, a workplace
expert and author of Getting from College to Career, says if you text your boss
and she prefers in-person meetings, “either your information won’t get across or
you’ll irritate [her].” Fortunately, there’s a simple fix: ask your boss how and
when to send updates. If you’re too shy to ask outright, then Pollak suggests
observing how they communicate with you. “If you have a boss who communicates
once a day by email, that’s the boss’ preferred frequency and method of
communication,” explains Pollak.
A cluttered, messy work space can give your boss the impression that you’re
lazy or disorganized, so try to keep your desk neat. “Never put more on your
desk than you’re going to work on for the day,” recommends Edwards. “At the end
of the day, make sure you set up for the next day. I may be working on five
things at once, but at the end of the day, they’re gone, and I set up for the
next day.” Most managers would rather you ask a question than make a mistake,
but many questions can be answered on your own. “Is this something you could
Google or ask a colleague?” wonders Pollak. “The internet is so vast that a lot
of information you can get yourself.” If you must approach your boss with a
question or issue, then Pollak recommends brainstorming beforehand. “Rather than
saying ‘This client is terrible. What should I do?’ think about potential
solutions,” she says.
Cell phones are practically ubiquitous in the workplace these days, but it’s
still disruptive and disrespectful when they go off during a meeting. Edwards
says that you should, “put your cell phone on vibrate or leave it in your own
office so it’s not a distraction.” That way you won’t be tempted to text
either
( )6.According to the article, how many pieces of advice are offered here?
.
A. Two B. Three C. Four D. Five(B)
( )7.What is this article about? .
A. How to be successful in the workplace.
B. How to communicate with your boss.
C. How to avoid quirks that annoy your boss.
D. How to utilize your mobile phones at work.
( )8.What does the phrase “to get across” in the sentence “…she prefers
in-person meetings, “either your information won’t get across or you’ll irritate
…” of the second paragraph mean? .
A. To be communicated B. To be passed
C. To be promoted D. To be anticipated(A)
( )9.According to the article, which of the following modes of communication
is the best when communicating with your boss? .
A. Any ways you think are appropriate.
B. In-person meetings.
C. Correspondence.
D. The way your boss communicates with you.(D)
( )10.Which of the following statements is not mentioned?
A. Employees should pay respect to their bosses anytime.
B. Employees should plan beforehand so as to show up at work on time.
C. Employees should not let their mobile phones go off during meetings.
D. Employees should keep their desks neat and organized.
Most of us are taught to pay attention to what is said—the words. Words do provide us with some information, but meanings are derived from so many other sources that it would hinder our effectiveness as a partner to a relationship to rely too heavily on words alone. Words are used to describe only a small part of the many ideas we associate with any given message. Sometimes we can gain insight into some of those associations if we listen for more than words. We don’t always say what we mean or mean what we say. Sometimes our words don’t mean anything except “ I’m letting off some steam. I don’t really want you to pay close attention to what I’m saying. Just pay attention to what I’m feeling.”
Mostly we mean several things at once. A person wanting to purchase a house says to the current owner, “This step has to be fixed before I’ll buy.” The owner says, “ It’s been like that for years.” Actually, the step hasn’t been like that for years, but the unspoken message is: “ I don’t want to fix it. We put up with it. Why can’t you?” The search for a more expansive view of meaning can be developed of examining a message in terms of who said it, when it occurred, the
related conditions or situation, and how it was said.
When a message occurs can also reveal associated meaning. Let us assume two couples do exactly the same amount of kissing and arguing. But one couple always kisses after an argument and the other couple always argues after a kiss. The ordering of the behaviors may mean a great deal more than the frequency of the behavior. A friend’s unusually docile behavior may only be understood by noting that it was preceded by situations that required an abnormal amount of assertiveness. Some responses may be directly linked to a developing pattern of responses and defy logic. For example, a person who says “No!” to a serials of charges like “You’re dumb,” “You’re lazy,” and “You’re dishonest,” may also say
“No!” and try to justify his or her response if the next statement is “And
you’re good looking.”
We would do well to listen for how messages are presented. The words, “If sure has been nice to have you over,” can be said with emphasis and excitement or ritualistically. The phrase can be said once or repeated several times. And the meanings we associate with the phrase will change accordingly. Sometimes if we say something infrequently it assumes more importance; sometimes the more we say something the less importance it assumes.
1.Effective communication is rendered possible between two conversing
partners, if ___.
A.they use proper words to carry their ideas.
B.they both speak truly of their own feelings.
C.they try to understand each other’s ideas beyond words.
D.they are capable of associating meaning with their words.
2.“I’m letting off some steam” in paragraph 1 means___.
A.I’m just calling your attention.
B.I’m just kidding.
C.I’m just saying the opposite.
D.I’m just giving off some sound.
3.The house-owner’s example shows that he actually means___.
A.the step has been like that for years.
B.he doesn’t think it necessary to fix the step.
C.the condition of the step is only a minor fault.
D.the cost involved in the fixing should be shared.
4.Some responses and behaviors may appear very illogical, but are justifiable
if___.
A.linked to an abnormal amount of assertiveness.
B.seen as one’s habitual pattern of behavior.
C.taken as part of an ordering sequence.
D.expressed to a series of charges.
5.The word “ritualistically” in the last paragraph equals something
done___.
A.without true intention.
B.light-heartedly.
C.in a way of ceremony.
D.with less emphasis.
