单选题The 18th-century statesman, Edmund Burke, once said "All that is needed for the triumph of a misguided cause is that good people do nothing." One such cause now seeks to end biomedical research because of the theory that animals have rights ruling out their use in research. Scientists need to respond forcefully to animal rights advocates, whose arguments are confusing the public and thereby threatening advances in health knowledge and care. Leaders of the animal rights movement target biomedical research because it depends on public funding, and few people understand the process of health care research. Hearing description of cruelty to animals in research settings, many are puzzled that anyone would deliberately harm an animal in medical researchers. For example, a grandmotherly woman advocating animal rights at a recent street fair was distributing a brochure that encouraged readers not to use anything that comes from or is tested in animals—no meat, no fur, no medicines. Asked if she opposed immunizations (免疫注射), she wanted to know if vaccines (疫苗) come from animal research. When assured that they do, she replied, "Then I would have to say yes. "Asked what will happen when epidemics return, she said, "Don't worry, scientists will find some way of using computers." Such well-meaning people just don't understand. Scientist must communicate their message to the public in a sympathetic, understandable way—in human terms, not in the language of molecular biology. We need to make clear the connection between animal research and a grandmother's hip replacement, a father's bypass operation, a baby's vaccinations, and even a pet' s shots. To those who are unaware that animal research was needed to produce these treatments, as well as new treatments and vaccines, animal research seems wasteful at best and cruel at worst. Much can be done. Scientists could adopt middle school classes and present their own research. They should be quick to respond to letters to the editor, lest animal rights misinformation go unchallenged and acquire a deceptive appearance of truth. Research institutions could be opened to tours, to show that laboratory animals receive humane care. Finally, because the ultimate stakeholders are patients, the health research community should actively recruit to its cause not only well-known personalities such as Stephen Cooper, who has made courageous statements about the value of animal research, but all who receive medical treatment. If good people do nothing, there is a real possibility that an uninformed citizenry will extinguish the precious embers (余火) of medical progress.

单选题British scientists are preparing to launch trials of a radical new way to fight cancer, which kills tumours by infecting them with viruses like the common cold. If successful, virus therapy could eventually form a third pillar alongside radiotherapy and chemotherapy in the standard arsenal against cancer, while avoiding some of the debilitating side-effects. Leonard Seymour, a professor of gene therapy at Oxford University, who has been working on the virus therapy with colleagues in London and the US, will lead the trials later this year. Cancer Research UK said yesterday that it was excited by the potential of Prof. Seymour's pioneering techniques. One of the country's leading geneticists, Prof. Seymour has been working with viruses that kill cancer cells directly, while avoiding harm to healthy tissue. "In principle, you've got something which could be many times more effective than regular chemotherapy, " he said. Cancer-killing viruses exploit the fact that cancer cells suppress the body's local immune system. "If a cancer doesn't do that, the immune system wipes it out. If you can get a virus into a tumour, viruses find them a very good place to be because there's no immune system to stop them replicating. You can regard it as the cancer's Achilles' heel. " Only a small amount of the virus needs to get to the cancer. "They replicate, you get a million copies in each cell and the cell bursts and they infect the tumour cells adjacent and repeat the process, " said Prof. Seymour. Preliminary research on mice shows that the viruses work well on tumours resistant to standard cancer drugs. "It's an interesting possibility that they may have an advantage in killing drug-resistant tumours, which could be quite different to anything we've had before. " Researchers have known for some time that viruses can kill tumour cells and some aspects of the work have already been published in scientific journals. American scientists have previously injected viruses directly into tumours but this technique will not work if the cancer is inaccessible or has spread throughout the body. Prof. Seymour's innovative solution is to mask the virus from the body's immune system, effectively allowing the viruses to do what chemotherapy drugs do—spread through the blood and reach tumours wherever they are. The big hurdle has always been to find a way to deliver viruses to tumours via the bloodstream without the body's immune system destroying them on the way. "What we've done is make chemical modifications to the virus to put a polymer coat around it - it's a stealth virus when you inject it, " he said. After the stealth virus infects the tumour, it replicates, but the copies do not have the chemical modifications. If they escape from the tumour, the copies will be quickly recognised and mopped up by the body's immune system. The therapy would be especially useful for secondary cancers, called metastases, which sometimes spread around the body after the first tumour appears. "There's an awful statistic of patients in the west. . . with malignant cancers; 75% of them go on to die from metastases, " said Prof. Seymour. Two viruses are likely to be examined in the first clinical trials: adenovirus, which normally causes a cold-like illness, and vaccinia, which causes cowpox and is also used in the vaccine against smallpox. For safety reasons, both will be disabled to make them less pathogenic in the trial, but Prof. Seymour said he eventually hopes to use natural viruses. The first trials will use uncoated adenovirus and vaccinia and will be delivered locally to liver tumours, in order to establish whether the treatment is safe in humans and what dose of virus will be needed. Several more years of trials will be needed, eventually also on the polymer-coated viruses, before the therapy can be considered for use in the NHS. Though the approach will be examined at first for cancers that do not respond to conventional treatments, Prof. Seymour hopes that one day it might be applied to all cancers.

单选题"In every known human society the male's needs for achievement can be recognized. . . In a great number of human societies men's sureness of their sex role is tied up with their right, or ability, to practice some activity that women are not allowed to practice. Their maleness in fact has to be underwritten by preventing women from entering some field or performing some feat. " This is the conclusion of the anthropologist Margaret Mead about the way in which the roles of men and women in society should be distinguished. If talk and print are considered it would seem that the formal emancipation of women is far from complete. There is a flow of publications about the continuing domestic bondage of women and about the complicated system of defences which men have thrown up around their hitherto accepted advantages, taking sometimes the obvious form of exclusion from types of occupation and sociable groupings, and sometimes the more subtle form of automatic doubt of the seriousness of women's pretensions to the level of intellect and resolution that men, it is supposed, bring to the business of running the world. There are a good many objective pieces of evidence for the erosion of men's status. In the first place, there is the widespread postwar phenomenon of the woman Prime Minister, in India, Sri Lanka and Israel. Secondly, there is the very large increase in the number of women who work, especially married women and mothers of children. More diffusely there are the increasingly numerous convergences between male and female behaviour: the approximation to identical styles in dress and coiffure, the sharing of domestic tasks, and the admission of women to all sorts of hitherto exclusively male leisure-time activities. Everyone carries round with him a fairly definite idea of the primitive or natural conditions of human life. It is acquired more by the study of humorous cartoons than of archaelology, but that does not matter since it is not significant as theory but only as an expression of inwardly felt expectations of people's sense of what is fundamentally proper in the differentiation between the roles of the two sexes. In this rudimentary natural society men go out to hunt and fish and to fight off the tribe next door while women keep the fire going. Amorous initiative is firmly reserved to the man, who sets about courtship with a club.

单选题The bird flu virus is mutating and becoming more dangerous to mammals, according to researchers. The discovery reinforces fears that a human pandemic of the disease could yet occur. Avian flu hit the headlines in 1997 when a strain called H5N1 jumped from chickens to people, killing 6 people in Hong Kong. Within 3 days, the country's entire chicken population was slaughtered and the outbreak was controlled. Since then new strains of virus have emerged, killing a further 14 people. As yet, no strain has been able to jump routinely from person to person. But if a more virulent strain evolves, the fear is that it could trigger widespread outbreaks, potentially affecting millions of people. Now, genetic and animal studies show that the virus is becoming more menacing to mammals. Immediate action is needed to stem the virus's transmission, says Hualan Chen from Harbin Veterinary Research Institute, China, who was involved in the research. Chen and colleagues studied 21 H5N1 flu virus samples taken from apparently healthy ducks, which act as a natural reservoir for the disease, in southern China between 1999 and 2002. The researchers inoculated groups of chickens, mice and ducks with virus samples taken from different years and waited to see which animals became ill. Their results are presented this week in the Proceedings of the National Academy of Sciences. As expected, ducks were immune to the virus's effects and the chickens fell sick. However, the mice also became ill, losing weight and the use of their limbs. Crucially, the severity of their illness was linked with the year from which the virus sample was taken. Viruses isolated in 2001 and 2002 made the animals more ill than those isolated earlier on. The findings hint that some time around 2001, the virus became adept at infecting mammals. Genetic analysis of the same samples reveals that the virus's DNA changed over that time, suggesting that accumulated mutations may have contributed to the increased virulence. Researchers are concerned that a virus that has acquired the ability to infect mice could also infect humans. "The disease could resurge at any time," warns virologist Marion Koopmans from the National Institute of Public Health and the Environment in Bilthoven, the Netherlands. The findings highlight the need for improved surveillance to ensure that any future outbreaks are curtailed, she says. Although domestic poultry is easily culled, wild animals are more difficult to contain. " It is impossible to eradicate the natural reservoir," says Koopmans, "So we need to learn to live with it." Birds may not be the only villains in this story, however. Chen believes that pigs may also play a part. In Asia, chickens and pigs are often kept in close proximity, so the virus may have shuffled back and forth between the 2 species, picking up mutations and becoming better at infecting mammalian hosts. Humans may then have caught the disease from swine.

单选题Americans believe no one stands still. If you are not moving ahead, you are falling behind. This attitude results in a nation of people committed to researching, experimenting and exploring. Time is the element that Americans save carefully. "We are slaves to nothing but the clock", it has been said. Time is treated as if it were something almost tangible, it is a precious commodity. Many people have a rather acute sense of the shortness of each lifetime. Once the sands have run out of a person's hourglass, they cannot be replaced. We want every minute to count. A foreigner's first impression of the U. S. is likely to be that everyone is in a rush—often under pressure. City people appear always to be hurrying to get where they are going, elbowing others as they try to complete their errands. Racing through daytime meals is part of the pace of life in this country. People in public eating-places are waiting for you to finish so they can be served and get back to work within the time allowed. Many newcomers to the States will miss the opening courtesies of a business call, for example. They will miss the ritual socializing that goes with a welcoming cup of tea or coffee that may be traditional in their own country. Normally, Americans do not assess their visitors in such relaxed surroundings over prolonged small talk; much less do they take them out for dinner, or around on the golf course while they develop a sense of trust and rapport. Rapport to most of us is less important than performance. We seek out evidence of past performances rather than evaluate a business colleague through social courtesies. Since we generally assess and probe professionally rather than socially, we start talking business very quickly. Some new arrivals will come from cultures where it is considered impolite to work too quickly. Unless a certain amount of time is allowed to elapse, it seems in their eyes as if the task being considered were insignificant, not worthy of proper respect. Assignments are thus felt to be added weight by the passage of time. In the U. S., however, it is taken as a sign of competence to solve a problem, or fulfill a job successfully, with rapidity. Usually, the more important a task is, the more capital, energy, and attention will be poured into it in order to "get it moving".

单选题It is said that in England death is pressing, in Canada inevitable and in California optional. Small wonder. Americans" life expectancy has nearly doubled over the past century. Failing hips can be replaced, clinical depression controlled, cataracts removed in a 30-minute surgical procedure. Such advances offer the aging population a quality of life that was unimaginable when I entered medicine 50 years ago. But not even a great health-care system can cure death—and our failure to confront that reality now threatens this greatness of ours. Death is normal; we are genetically programmed to disintegrate and perish, even under ideal conditions. We all understand that at some level, yet as medical consumers we treat death as a problem to be solved. Shielded by third-party payers from the cost of our care, we demand everything that can possibly be done for us, even if it" s useless. The most obvious example is late-stage cancer care. Physicians frustrated by their inability to cure the disease and fearing loss of hope in the patient—too often offer aggressive treatment far beyond what is scientifically justified. In 1950, the U. S. spent 0.7 billion on health care. In 2002, the cost will be billion. Anyone can see this trend is unsustainable. Yet few seem willing to try to reverse it. Some scholars conclude that a government with finite resources should simply stop paying for medical care that sustains life beyond a certain age—say 83 or so. Former Colorado governor Richard Lamm has been quoted as saying that the old and infirm "have a duty to die and get out of the way" , so that younger, heallhier people can realize their potential. I would not go that far. Energetic people now routinely work through their 60s and beyond, and remain dazzlingly productive. At 78, Viacom chairman Sumner Redstone- jokingly claims to be 53. Supreme Court Justice Sandra Day O" Connor is in her 70s, and former surgeon general C. Everett Koop chairs an Internet start-up in his 80s. These leaders are living proof that prevention works and that we can manage the health problems that come naturally with age. As a mere 68-year-old, I wish to age as productively as they have. Yet there are limits to what a society can spend in this pursuit. As a physician, I know the most costly and dramatic measures may be ineffective and painful. I also know that people in Japan and Sweden, countries that spend far less on medical care, have achieved longer, healthier lives than we have. As a nation, we may be overfunding the quest for unlikely cures while underfunding research on humbler therapies that could improve people" s lives.

单选题Although genetic mutations in bacteria and viruses can lead to epidemics, some epidemics are caused by bacteria and viruses that have undergone no significant genetic change. In analyzing the latter, scientists have discovered the importance of social and ecological factors to epidemics. Poliomyelitis, for example, emerged as an epidemic in the United States in the twentieth century, by then, modern sanitation was able to delay exposure to polio until adolescence or adulthood, at which time polio infection produced paralysis. Previously, infection had occurred during infancy, when it typically provided lifelong immunity without paralysis. Thus, the hygiene that helped prevent typhoid epidemics indirectly fostered a paralytic polio epidemic. Another example is Lyme disease, which is caused by bacteria that are transmitted by deer ticks. It occurred only sporadically during the late nineteenth century, but has recently become prevalent in parts of the United States, largely due to an increase in the deer population that occurred simultaneously with the growth of the suburbs and increased outdoor recreational activities in the deer's habitat. Similarly, an outbreak of dengue hemorrhagic fever became an epidemic in Asia in the 1950s because of ecological changes that caused Aedesaegypti, the mosquito that transmits the dengue virus, to proliferate. The stage is now set in the United States for a dengue epidemic because of the inadvertent introduction and wide dissemination of another mosquito, Aedesalbopictus.

单选题When it comes to health, which is more important, nature or nurture? You may well think your genes are a more important predictor of health and ill health. Not so fast. In fact, it transpires that our everyday environment outweighs our genetics, big time, when it comes to measuring our risk of disease. The genome is out—welcome the exposome. "The exposome represents everything a person is exposed to in the environment, that's not in the genes, " says Stephen Rappaport, environmental health scientist at the University of California, Berkeley. That includes stress, diet, lifestyle choices, recreational and medicinal drug use and infections, to name a few. "The big difference is that the exposome changes throughout life as our bodies, diets and lifestyles change, " he says. While our understanding of the human genome has been growing at an exponential rate over the last decade, it is not as helpful as we hoped in predicting diseases. "Genes only contribute 10 percent to the overall disease burden, " says Rappaport. "Knowing genetic risk factors can prove absolutely futile , " says Jeremy Nicholson at Imperial College London. He points to work by Nina Paynter at the Brigham and Women's Hospital in Boston, who investigated the effect of 101 genetic markers implicated in heart disease. After following over 19, 000 women for 12 years, she found these markers were not able to predict anything about the incidence of heart disease in this group. On the other hand, the impact of environmental influences is still largely a mystery. " There's an imbalance between our ability to investigate the genome and the environment, " says Chris Wild, director of the International Agency for Research on Cancer, who came up with the idea of the exposome. In reality, most diseases are probably caused by a combination of the two, which is where the exposome comes in. "The idea is to have a comprehensive analysis of a person's full exposure history, " says Wild. He hopes a better understanding of exposures will shed a brighter light on disease risk factors. There are likely to be critical periods of exposure in development. For example, the time from birth to 3 years of age is thought to be particularly important. "We know that this is the time when brain connections are made, and that if you are obese by this age, you'll have problems as an adult, " says Nicholson.

单选题Among the most stressful of worries are death, illness, loss of work, money problem, marital problems and retirement. Such worries have rational basis, but we are curiously irrational in the way we pursue them. For example, fear of death is as strong among young adults as among the elderly. It is equally surprising that we are as worried the hour before having a tooth filled as when we face major surgery. It is difficult to decide at what point worrying ceases to be "normal", but it is clearly reasonable to worry. People get seriously ill, planes go awry, tube trains sometimes crash. In practice, anxiety is judged to be pathological when it curtails our ability to lead a normal existence. We can manage perfectly well without travelling in planes or lifts, and an evening out isn" t spoiled by the fact that we are unable to leave the house without triple-checking the frontdoor lock. Such worries are widespread in the general population. In its extreme form, anxiety may be experienced either as a generalized, "free-floating" state(the sufferer becomes tense and frightened for no apparent reason), or it may be more specifically focused - for example on open spaces, enclosed situations or certain insects or animals. Many people will have experienced the former - taut muscles, dry mouth and the feeling of agitation, dread or even panic - while mild phobias are also very common. But at less intense levels, anxiety and worrying have great value. They help us to avoid trouble, or to cope with it when it cannot be avoided. Worrying may be an internal impulse, allowing us to solve problems at times of crisis. By worrying, we may understand better the origins of the worry and thereby avoid a possible breakdown. It may also play a significant part in helping us to come to terms with reality. In everyday life, anxiety energizes us and improves performance of a wide variety of tasks, it also galvanizes us to achieve more. Without it, it is difficult to see how there could be either social or intellectual progress. So worrying is not after all an unproductive activity. Perhaps the time to be worried is when you" re not worrying.

单选题During the past 30 years or so, health care has increasingly become a form of business. In addition , the environment surrounding health care has been greatly altered by the advent of more sophisticated medical technologies and increased specialization. It is no longer true to say that doctors regard their profession as a sacred calling, and while the doctor-patient relationship still remains, it is not the relationship based solely on trust which it used to be. Of course there are many doctors who have endeavored to increase the transparency of their behavior as medical professionals, and patients can receive effective treatment when such doctors work closely together and share notes. An example of such cooperation can be found in the field of remote health care, which has been introduced on an experimental basis in several regions. Since most medical specialists live in cities, patients who live in the country have to travel a long distance to consult a specialist. This is especially hard on the elderly, both financially and physically. Through a computer network, patients who live in the country can consult a medical specialist in the city, tell him their symptoms, and receive advice without the need for a journey to the specialist' s office. Also, with several doctors being assigned to a single patient, the transparency of each doctor' s behavior is further ensured. On the other hand, however, it is also true that remote health consultation is not generally regarded as a form of medical treatment. For any sort of consultation to be regarded as medical treatment, most people feel that the patient must actually visit the doctor, and undergo an examination by the doctor in person. Remote health care is essentially a means for doctors to work as a team. In order for this to be practicable, it is important to establish a system whereby financial support can be extended to a doctor who, as a member of a medical team, provides only information. Establishment of such a system will further advance the cause of " free access to information" in the health care field.

单选题On September 7, 2001, a 68-year-old woman in Strasbourg, France, had her gall bladder (胆囊) removed by-surgeons operating, via computer form New York. It was the first complete telesurgery procedure performed by surgeons nearly 4, 000 miles away from their patient. In New York, Marescaux teamed up with surgeon Michel Gagner to perform the historic long-distance operation. A high-speed fiber-optic service provided by France Telecom made the connection between New York and Strasbourg. The two surgeons controlled the instruments using an advanced robotic surgical system, designed by Computer Motion Inc. that enabled the procedure to be minimally invasive. The patient was released from the hospital after about 48 hours and regained normal activity the following week. The high-speed fiber-optic connection between New York and France made it possible to overcome a key obstacle to telesurgery time delay. It was crucial that a continuous time delay of less than 200 milliseconds be maintained throughout the operation, between the surgeon's movements in New York and the return video (from Strasbourg) on his screen. The delay problem includes video coding decoding and signal transmission time. France Telecom's engineers achieved an average time delay of 150 milliseconds. "I felt as comfortable operating on my patient as if I had been in the room, " says Marescaux. The successful collaboration (合作) among medicine, advanced technology, and telecomm unications is likely to have enormous implications for patient care and doctor training. Highly skilled surgeons may soon regularly perform especially difficult operations through long-distance procedures. The computer systems used to control surgical movement can also lead to a breakthrough in teaching surgical techniques to a new generation of physicians. More surgeons-in-training will have the opportunity to observe their teachers in action in telesurgery operating rooms around the world. Marescaux describes the success of the remotely performed surgical procedure as the beginning of a "third revolution" in surgery within the last decade. The first was the arrival of minimally invasive surgery, enabling procedures to be performed with guidance by a camera, meaning that the abdomen (腹部) and thorax (胸腔) do not have to be opened. The second was the introduction of computer-assisted surgery, where complicated software algorithms (计算法) enhance the safety of the surgeon's movements during a procedure, making them more accurate, while introducing the concept of distance between the surgeon and the patient. It was thus natural to imagine that this distance-currently several meters in the operating room could potentially be up to several thousand kilometers.

单选题If you are caught in a downpour, it is better to run for shelter than walk, researchers in the US advise. This may sound obvious, but an earlier study in Britain suggested that you would get just as wet running as walking. In 1995, Stephen Belcher of the University of Reading and his students calculated how much water falls on top of your head and how much you sweep up on your front as you move forward. Obviously, you would get wettest standing still, and less wet the faster you moved. But the Reading team found that the benefits of running faster than about 3 metres per second—which they described as a walking pace—were tiny. Thomas Peterson and Trevor Wallis, meteorologists at the National Climatic Data Center in Asheville, North Carolina, had a hunch that this was wrong. They realized that the Reading team had overestimated the average walking pace, so they reworked the calculations for a walking pace of 1.5 metres per second and a running speed of 4 meters per second. Peterson and Wallis conclude in the latest issue of Weather that a walker would get 16 per cent wetter than a runner over a distance of 100 meters in drizzle. In heavy rain, this would rise to 23 per cent. When the researchers allowed for the way that runners tend to lean forward, sheltering the front of their bodies but increasing the rainfall on their backs, they found that a walker would get 36 per cent wetter than a runner in heavy rain. Not content with theory alone, Peterson and Wallis decided to test their ideas. " If verification requires an $ 80 million satellite, one may have to forgo verification, " says Peterson. "But if it involves a simple experiment, that" s another matter. " Peterson and Wallis are roughly the same size. Wearing identical clothing, one ran 100 meters in heavy rain and the other walked. They weighed their clothes before and after the experiment. This showed that the walker bad absorbed 0.22 kilograms of water, while the runner had soaked up only 0. 13 kilograms. This is about 40 per cent less, is line with the model" s predictions. Belcher says that his team" s work was a bit of fun, and that apart from the confusion over what a typical walking speed is, their results were similar to those of Peterson and Wallis. "I"m delighted to see that their experiments gave results in qualitative agreement with the model," says Belcher. But why not just take an umbrella? For anyone thinking of taking the easy way out, Wallis has a warning: "Running with an umbrella has a negative impact on your aerodynamics. "

单选题Modern biology is based on several unifying themes, such as the cell theory, genetics and inheritance, Francis Crick's central dogma of information flow, and Darwin and Wallace's theory of evolution by natural selection. In this first unit we will examine these themes and the nature of science. The ancient Greek philosopher Anaxiamander (611- 547 B. C. ) and the Roman philosopher Lucretius (99 – 55 B. C. ) coined the concept that all living things were related and that they had changed over time. The classical science of their time was observational rather than experimental. Another ancient Greek philosopher Aristotle, developed his Scala Naturae, or Ladder of Life, to explain his concept of the advancement of living things from inanimate matter to plants, then animals and finally man. This concept of man as the "crown of creation" still plagues modern evolutionary biologists. Post-Aristotlean "scientists" were constrained by the prevailing thought patterns of the Middle Ages—the inerrancy of the biblical book of Genesis and the special creation of the world in a literal six days of the 24-hour variety. Archbishop James Ussher of Ireland, in the late 1600's calculated the age of the earth based on the geneologies from Adam and Eve listed in the biblical book of Genesis. According to Ussher's calculations, the earth was formed on October 22, 4004 B. C. These calculations were part of Ussher's book, History of the World. The chronology he developed was taken as factual, and was even printed in the front pages of Bibles. Ussher's ideas were readily accepted, in part because they posed no threat to the social order of the times; comfortable ideas that would not upset the linked apple carts of church and state. Often new ideas must "come out of left field", appearing as wild notions, but in many cases prompting investigation which may later reveal the "truth". Ussher's ideas were comfortable, the Bible was viewed as correct, therefore the earth must be only 5, 000 years old. Geologists had for some time doubted the "truth" of a 5, 000 year old earth. Leonardo da Vinci (painter of the Last Supper, and the Mona Lisa, architect and engineer) calculated the sedimentation rates in the Po River of Italy. Da Vinci concluded it took 200, 000 years to form some nearby rock deposits. Galileo, convicted heretic for his contention that the Earth was not the center of the Universe, studied fossils (evidence of past life) and concluded that they were real and not inanimate artifacts. James Hutton, regarded as the father of modern geology, developed the Theory of Uniformitarianism, the basis of modern geology and paleontology. According to Hutton's work, certain geological processes operated in the past in much the same fashion as they do today, with minor exceptions of rates, etc. Thus many geological structures and processes cannot be explained if the earth was only a mere 5, 000 years old.

单选题Here is a shaming statistic: divide the US by race, sex and county of residence, and differences in average life expectancy across the various groups can exceed 30 years. The most disadvantaged look like denizens of a poor African country: a boy born on a Native American reservation in Jackson County, South Dakota, for example, will be lucky to reach his 60th birthday. A typical child in Senegal can expect to live longer than that. America is not alone in this respect. While the picture is extreme in other rich nations, health inequalities based on race, sex and class exist in most societies—and are only partly explained by access to healthcare. But fresh insights and solutions may soon be at hand. An innovative project in Chicago to unite sociology and biology is blazing the trail (开创), after discovering that social isolation and fear of crime can help to explain the alarmingly high death rate from breast cancer among the city's black women. Living in these conditions seems to make tumors more aggressive by changing gene activity, so that cancer cells can use nutrients more effectively. We are already familiar with the lethal effect of stress on people clinging to the bottom rungs of the societal ladder, thanks to pioneering studies of British civil servants conducted by Michael Marmot of University College London. What's exciting about the Chicago project is that it both probes the mechanisms involved in a specific disease and suggests precise remedies. There are drugs that may stave tumors of nutrients and community coordinators could be employed to help reduce social isolation. Encouraged by the US National Institutes of Health, similar projects are springing up to study other pockets of poor health in populations ranging from urban black men to white poor women in rural Appalachia. To realize the full potential of such projects, biologists and sociologists will have to start treating one other with a new respect and learn how to collaborate outside their comfort zones. Too many biomedical researchers still take the arrogant view that sociology is a "soft science" with little that's serious to say about health. And too many sociologists reject any biological angle—fearing that their expertise will be swept aside and that this approach will be used to bolster discredited theories of eugenics, or crude race-based medicine. It's time to drop these outdated attitudes and work together for the good of society's most deprived members. More important, it's time to use this fusion of biology and sociology to inform public policy. This endeavor has huge implications, not least in cutting the wide health gaps between blacks and whites, rich and poor.

单选题The economic recession of the 1980s and its impact on the quality of life in Third World countries highlighted how important health is for development and how essential it is for concern about public health to feature at the very heart of development policies. The fact is that it is no longer possible to meet the soaring costs of health and the emergence of new risks — such as AIDS — unless health is built in among the priority economic objectives. Health and development are indissolubly linked, and the era when health tended to rate very low in the list of economic targets is past and gone. But a lot remains to be done: the health care services can no longer be left on their own to face up to those new situations, which must be taken into consideration whenever each country constantly reviews its economic objectives. It was long thought that technical progress would provide the solution to all health problems. That this is not the case is proved by the impact that environmental degradation has had on human health, by the pandemic of AIDS, by the way the much greater mobility of people has encouraged the rapid transmission of diseases, and by the health consequences of modern life-styles. Today we have to find radically new approaches if we are to avoid the present world situation turning into an uncontrollable health. It is essential for national policy-makers in the field of social welfare to give every citizen much greater decision-making power, especially by ensuring that vulnerable communities have direct access to decisions which concern them. Individuals and communities must be given the opportunity to assume far greater responsibility for their own health and quality of life, by creating a climate that is favourable to well-being and by offering the necessary incentives and support. Independent bodies such as nongovernmental organizations also have an important role to play in making widely available the information and awareness that people must have if they are to make the right choices and take the right social decisions. This is one of the greatest challenges as we approach the end of the twentieth century. If we show ourselves ready to meet that challenge, the citizens of the third millennium will have the knowledge and the means empowering them to build a society where health — a human right for every man and woman — will be within the reach of all.

单选题I remember meeting him one evening with his pushcart. I had managed to sell all my papers and was coming home in the snow. It was that strange hour in downtown New York when the workers were pouring homeward in the twilight. I marched among thousands of tired men and women whom the factory whistles had unyoked. They flowed in rivers through the clothing factory districts, then down along the avenues to the East Side. I met my father near Cooper Union. I recognized him, a hunched, frozen figure in an old overcoat standing by a banana cart. He looked so lonely; the tears came to my eyes. Then he saw me, and his face lit with his sad, beautiful smile — Charlie Chaplin"s smile. "Arch, it"s Mikey," he said. "So you have sold your papers! Come and eat a banana." He offered me one. I refused it. I felt it crucial that my father sell his bananas, not give them away. He thought I was shy, and coaxed and joked with me, and made me eat the banana. It smelled of wet straw and snow. "You haven"t sold many bananas today, pop," I said anxiously. He shrugged his shoulders. "What can I do? No one seems to want them." It was true. The work crowds pushed home morosely over the pavements. The rusty sky darkened over New York building, the tall street lamps were lit, innumerable trucks, street cars and elevated trains clattered by. Nobody and nothing in the great city stopped for my father"s bananas. "I ought to yell," said my father dolefully. "I ought to make a big noise like other peddlers, but it makes my throat sore. Anyway, I"m ashamed of yelling, it makes me feel like a fool." I had eaten one of his bananas. My sick conscience told me that I ought to pay for it somehow. I must remain here and help my father. "I"ll yell for you, pop," I volunteered. "Arch, no," he said, "go home; you have worked enough today. Just tell momma I"ll be late." But I yelled and yelled. My father, standing by, spoke occasional words of praise, and said I was a wonderful yeller. Nobody else paid attention. The workers drifted past us wearily, endlessly; a defeated army wrapped in dreams of home. Elevated trains crashed; the Cooper Union clock burned above us; the sky grew black, the wind poured, the slush burned through our shoes. There were thousands of strange, silent figures pouring over the sidewalks in snow. None ot them stopped to buy bananas. I yelled and yelled, nobody listened. My father tried to stop me at last. "Nu," he said smiling to console me, "that was wonderful yelling. Mikey. But it"s plain we are unlucky today! Let"s go home." I was frantic, and almost in tears. I insisted on keeping up my desperate yells. But at last my father persuaded me to leave with him.

单选题Researchers at Yale University Medical School and the Olin Neuropsychiatry Research Center at the Institute of Living in Hartford, Conn., have taken a pretty good look at what happens in the brain of a drunken driver. And it isn"t pretty. Using【C1】______scans, the scientists compared the neural activity that【C2】______on and off like lights on a police car as both sober【C3】______game. The maps of activity in different areas of the brain【C4】______in new detail the impact that drinking has on a complicated【C5】______task such as driving. "No one had seen that in a scanner【C6】______." said Dr. Godfrey Pearlson, a Yale psychiatrist and director of the Olin Center. Pearlson and Vince Calhoun, a researcher at Yale and Olin, first conducted brain scans on【C7】______drivers as they played the driving simulation game and then as they watched others play the game. Those scans gave the researchers a baseline of【C8】______activity in the unimpaired driver. Subjects were then given a low dose or a high dose of booze—enough to get their blood alcohol content to either 0.04 percent or 0.10 percent. An inebriated driver often will speed because alcohol has affected the cerebellum, a primitive area of the brain involved in【C9】______function, the researchers found. But drunken drivers【C10】______in and out of traffic because of errors in the front parietal cortex, which translates sensory information and helps in the decision-making process, Pearlson said. Drinking did not seem to change activity in five other areas of the brain associated with driving, such as vision centers, the researchers found. But to the surprise of no one, the more the subjects drank, the more trouble they had with their driving.

单选题Just because you" re better educated doesn" t mean that you" re any more rational than everyone else, no matter how hard you may try to give that impression. Take the selection of lottery numbers. A survey in Florida described at this year" s annual meeting of the American Association for the Advancement of Science shows that better educated people try to use random number systems to pick their lottery numbers. Despite the apparent logic of choosing random numbers, however, their chances of winning are no better than those of ordinary folk who use birthdays, anniversaries and other "lucky" dates. Nor are they better off than those who draw on omens and intuitions, picking numbers seen on car number-plates and in dreams. But no doubt they feel a lot more rational. That appearance of "rationality" may be a dangerous thing. Scientists are not immune to subtle and subjective influences on their judgements. Take the data from a survey of the public and member of the British Society of Toxicology discussed at the same meeting. The survey showed that most people agree with the view that animals can be used to help predict how human will react to chemicals, and that if a chemical causes cancer in an animal, we can be "reasonably sure" it will cause cancer in humans. The toxicologists, however, are more circumspect. They accept the fast statement but less likely to agree that if a chemical causes cancer in an animal, it will do so in a human. Can this difference be attributed to their expertise? Perhaps. But consider the considerable variation among toxicologists: those who were young, female, working in academia rather than industry or who felt that technology is not always used for the good of all, were more likely to agree that what causes cancer in an animal will cause cancer in a human. Maybe we need to think more about how who we are affects our "rational" decisions.

单选题The idea of test-tube babies may make you either delighted at the wonders of modern medicine or irritated while considering the moral, or legal, or technological implications of starting life in a laboratory. But if you've ever been pregnant yourself, one thing is certain: You wonder what it's like to carry a test-tube baby. Are these pregnancies normal? Are the babies normal? The earliest answers come from Australia, where a group of medical experts at the Queen Victoria Medical Center in Melbourne have taken a look at the continent's first nine successful in vitro pregnancies. The Australians report that the pregnancies themselves seemed to proceed according to plan, but at birth some unusual trends did show up. Seven of the nine babies turned out to be girls. Six of the nine were delivered by Caesarean section. Undone baby, a twin, was born with a serious heart defect and a few days later developed life-threatening problems. What does it all mean? Even the doctors don't know for sure, because the numbers are so small. The proportion of girls to boys is high, but until there are many more test-tube babies none will know whether that's something that just happened to be like that or something special that happens when egg meets sperm in a test tube instead of a Fallopian tube. The same thing is true of the single heart defect; it usually shows up in only 15 out of 60, 000 births in that part of Australia, but the fact that it occurred in one out of nine test-tube babies does not necessarily mean that they are at special risk. One thing the doctors can explain is the high number of Caesareans. Most of the mothers were older, had long histories of fertility problems and in some cases had had surgery on the fallopian tubes, all of which made them likely candidates for Caesareans anyway. The Australian researchers report that they are quite encouraged. All the babies are now making normal progress even the twin with the birth defects.

单选题Despite Denmark's manifest virtues, Danes never talk about how proud they are to be Danes. This would sound weird in Danish. When Danes talk to foreigners about Denmark, they always begin by commenting on its tininess, its unimportance, the difficulty of its language, the general small-mindedness and self-indulgence of their countrymen and the high taxes. No Dane would look you in the eye and say, "Denmark is a great country. " You're supposed to figure this out for yourself. It is the land of the silk safety net, where almost half the national budget goes toward smoothing out life's inequalities, and there is plenty of money for schools, day care, retraining programmers, job seminars—Danes love seminars: three days at a study centre hearing about waste management is almost as good as a ski trip. It is a culture bombarded by English, in advertising, pop music, the Internet, and despite all the English that Danish absorbs — there is no Danish Academy to defend against it — old dialects persist in Jutland that can barely be understood by Copenhageners. It is land where, as the saying goes, "Few have too much and fewer have too little, "and a foreigner is struck by the sweet egalitarianism that prevails, where the lowliest clerk gives you a level gaze, where Sir and Madame have disappeared from common usage, even Mr. and Mrs. It's a nation of recyclers—about 55% of Danish garbage gets made into something new—and no nuclear power plants. It's a nation of tireless planners. Trains run on time. Things operate well in general. Nonetheless, it is an orderly land. You drive through a Danish town, it comes to an end at a stone wall, and on the other side is a field of barley, a nice clean line, town here, country there. It is not a nation of jay-walkers. People stand on the curb and wait for the red light to change, even if it's 2 a. m. and there's not a car in sight. However, Danes don't think of themselves as a waiting-at-2. a. m. -for-the-green-light people—that's how they see Swedes and Germans. Danes see themselves as jazzy people, improvisers, more free spirited than Swedes, but the truth is (though one should not say it) that Danes are very much like Germans and Swedes. Orderliness is a main selling point. Denmark has few natural resources, limited manufacturing capability; its future in Europe will be as a broker, banker, and distributor of goods. You send your goods by container ship to Copenhagen, and these bright, young, English-speaking, utterly honest, highly disciplined people will get your goods around to Scandinavia, the Baltic Stares, and Russia. Airports, seaports, highways, and rail lines are ultramodern and well-maintained. The orderliness of the society doesn't mean that Danish lives are less messy or lonely than yours or mine, and no Dane would tell you so. You can hear plenty about bitter family feuds and the sorrows of alcoholism and about perfectly sensible people who went off one day and killed themselves. An orderly society cannot exempt its members from the hazards of life. But there is a sense of entitlement and security that Danes grow up with. Certain things are yours by virtue of citizenship, and you shouldn't feel bad for taking what you're entitled to, you're as good as anyone else. The rules of the welfare system are clear to everyone, the benefits you get if you lose your job, the steps you take to get a new one; and the orderliness of the system makes it possible for the country to weather high unemployment and social unrest without a sense of crisis.