雅思真题4阅读及翻译
Tropical Rainforests

Adults and children are frequently confronted with statements about the alarming rate of loss of tropical rainforests. For example, one graphic illustration to which children might readily relate is the estimate that rainforests are being destroyed at a rate equivalent to one thousand football fields every forty minutes - about the duration of a normal classroom period. In the face of the frequent and often vivid media coverage, it is likely that children will have formed ideas about rainforests - what and where they are, why they are important, what endangers them - independent of any formal tuition. It is also possible that some of these ideas will be mistaken.

Many studies have shown that children harbour misconceptions about ‘pure' curriculum science. These misconceptions do not remain isolated but become incorporated into a multifaceted, but organised, conceptual framework, making it and the component ideas, some of which are erroneous，more robust but also accessible to modification. These ideas may be developed by children absorbing ideas through the popular media. Sometimes this information may be erroneous. It seems schools may not be providing an opportunity for children to re-express their ideas and so have them tested and refined by teachers and their peers.

Despite the extensive coverage in the popular media of the destruction of rainforests, little formal information is available about children’s ideas in this area. The aim of the present study is to start to provide such information, to help teachers design their educational strategies to build upon correct ideas and to displace misconceptions and to plan programmes in environmental studies in their schools.The study surveys children’s scientific knowledge and attitudes to rainforests. Secondary school children were asked to complete a questionnaire containing five open-form questions. The most frequent responses to the first question were descriptions which are self-evident from the term "rainforest". Some children described them as damp, wet or hot. The second question concerned the geographical location of rainforests. The commonest responses were continents or countries：Africa (given by 43% of children), South America (30%), Brazil (25%). Some children also gave more general locations, such as being near the Equator.

Responses to question three concerned the importance of rainforests. The dominant idea, raised by 64% of the pupils, was that rainforests provide animals with habitats. Fewer students responded chat rainforests provide plant habitats, and even fewer mentioned the indigenous populations of rainforests. More girls (70%) than boys (60%) raised die idea of rainforest as animal habitats.Similarly, but at a lower level, more girls (13%) than boys (5%) said that rainforests provided human habitats. These observations are generally consistent with our previous studies of pupils’ views about the use and conservation of rainforests, in which girls were shown to be more sympathetic to animals and expressed views which seem to place an intrinsic value on non-human animal life.

The fourth question concerned the causes of the destruction of rainforests. Perhaps encouragingly, more than half of the pupils (59%) identified chat it is human activities which are destroying rainforests, some personalising the responsibility by the use of terms such as "we are". About 18% of the pupils referred specifically to logging activity.

One misconception, expressed by some 10% of the pupils, was chat acid rain is responsible for rainforest destruction； A similar proportion said chat pollution is destroying rainforests. Here, children are confusing rainforest destruction with damage to the forests of Western Europe by these factors. While two fifths of the students provided the information that the rainforests provide oxygen, in some cases this response also embraced. The misconception that rainforest destruction would reduce atmospheric oxygen, making the atmosphere incompatible with human life on Earth.

In answer to the final question about the importance of rainforest conservation, the majority of children simply said that we need rainforests to survive. Only a few of the pupils (6%) mentioned that rainforest destruction may contribute to global warming. This is surprising considering the high level of media coverage on this issue. Some children expressed the idea that the conservation of rainforests is not important.The results of this study suggest that certain ideas predominate in the thinking of children about rainforests. Pupils’ responses indicate some misconceptions in basic scientific knowledge of rain forests’ ecosystems such as their ideas about rainforests as habitats for animals, plants and humans and the relationship between climatic change and destruction of rainforests.

Pupils did not volunteer ideas that suggested that they appreciated the complexity of causes of rainforest destruction. In other words, they gave no indication of an appreciation of either the range of ways in which rainforests are important or the complex social, economic and political factors which drive the activities which are destroying the rainforests. One encouragement is that the results of similar studies about other environmental issues suggest that older children seem to acquire the ability to appreciate, value and evaluate conflicting views. Environmental education offers an arena  in which these skills can be developed, which is essential for these children as future decision-makers.

剑4T1P2What Do Whales Feel

Some of the senses that we and other terrestrial mammals take for granted are either reduced or absent in cetaceans or fail to function well in water. For example, it appears from their brain structure that toothed species are unable to smell. Baleen species, on the other hand, appear to have some related brain structures but it is not known whether these are functional. It has been speculated that, as the blowholes evolved and migrated to the top of the head, the neural pathways serving sense of smell may have been nearly all sacrificed. Similarly, although at least some cetaceans have taste buds, the nerves serving these have degenerated or are rudimentary.

The sense of touch has sometimes been described as weak too, but this view is probably mistaken. Trainers of captive dolphins and small whales often remark on their animals’ responsiveness to being touched or rubbed, and both captive and free ranging cetacean individuals of all species (particularly adults and calves, or members of the same subgroup) appear to make frequent contact. This contact may help to maintain order within a group, and stroking or touching are part of the courtship ritual in most species. The area around the blowhole is also particularly sensitive and captive animals often object strongly to being touched there.

The sense of vision is developed to different degrees in different species. Baleen species studied at close quarters underwater –specifically a grey whale calf in captivity for a year, and free-ranging right whales and humpback whales studied and filmed off Argentina and Hawaii – have obviously tracked objects with vision underwater, and they can apparently see moderately well both in water and in air. However, the position of the eyes so restricts the field of vision in baleen whales that they probably do not have stereoscopic vision.

On the other hand, the position of the eyes in most dolphins and porpoises suggests that they have stereoscopic vision forward and downward. Eye position in freshwater dolphins, which often swim on their side or upside down while feeding, suggests that what vision they have is stereoscopic forward and upward. By comparison, the bottlenose dolphin has extremely keen vision in water. Judging from the way it watches and tracks airborne flying fish, it can apparently see fairly well through the air–water interface as well. And although preliminary experimental evidence suggests that their in-air vision is poor, the accuracy with which dolphins leap high to take small fish out of a trainer’s hand provides anecdotal evidence to the contrary.

Such variation can no doubt be explained with reference to the habitats in which individual species have developed. For example, vision is obviously more useful to species inhabiting clear open waters than to those living in turbid rivers and flooded plains. The South American boutu and Chinese beiji, for instance, appear to have very limited vision, and the Indian susus are blind, their eyes reduced to slits that probably allow them to sense only the direction and intensity of light.

Although the senses of taste and smell appear to have deteriorated, and vision in water appears to be uncertain, such weaknesses are more than compensated for by cetaceans’ well-developed acoustic sense. Most species are highly vocal, although they vary in the range of sounds they produce, and many forage for food using echolocation. Large baleen whales primarily use the lower frequencies and are often limited in their repertoire. Notable exceptions are the nearly song-like choruses of bowhead whales in summer and the complex, haunting utterances of the humpback whales. Toothed species in general employ more of the frequency spectrum, and produce a wider variety of sounds, than baleen species (though the sperm whale apparently produces a monotonous series of high-energy clicks and little else). Some of the more complicated sounds are clearly communicative, although what role they may play in the social life and ‘culture’ of cetaceans has been more the subject of wild speculation than of solid science.

剑4T1P3Visual Symbols and the Blind

Part 1

From a number of recent studies, it has become clear that blind people can appreciate the use of outlines and perspectives to describe the arrangement of objects and other surfaces in space. But pictures are more than literal representations. This fact was drawn to my attention dramatically when a blind woman in one of my investigations decided on her own initiative to draw a wheel as it was spinning. To show this motion, she traced a curve inside the circle (Fig. 1). I was taken aback. Lines of motion, such as the one she used, are a very recent invention in the history of illustration. Indeed, as art scholar David Kunzle notes, Wilhelm Busch, a trend-setting nineteenth-century cartoonist, used virtually no motion lines in his popular figures until about 1877.

When I asked several other blind study subjects to draw a spinning wheel, one particularly clever rendition appeared repeatedly: several subjects showed the wheel’s spokes as curved lines. When asked about these curves, they all described them as metaphorical ways of suggesting motion. Majority rule would argue that this device somehow indicated motion very well. But was it a better indicator than, say, broken or wavy lines – or any other kind of line, for that matter? The answer was not clear. So I decided to test whether various lines of motion were apt ways of showing movement or if they were merely idiosyncratic marks. Moreover, I wanted to discover whether there were differences in how the blind and the sighted interpreted lines of motion.

To search out these answers, I created raised-line drawings of five different wheels, depicting spokes with lines that curved, bent, waved, dashed and extended beyond the perimeter of the wheel. I then asked eighteen blind volunteers to feel the wheels and assign one of the following motions to each wheel: wobbling, spinning fast, spinning steadily, jerking or braking. My control group consisted of eighteen sighted undergraduates from the University of Toronto.

All but one of the blind subjects assigned distinctive motions to each wheel. Most guessed that the curved spokes indicated that the wheel was spinning steadily; the wavy spokes, they thought, suggested that the wheel was wobbling; and the bent spokes were taken as a sign that the wheel was jerking. Subjects assumed that spokes extending beyond the wheel’s perimeter signified that the wheel had its brakes on and that dashed spokes indicated the wheel was spinning quickly.

In addition, the favoured description for the sighted was the favoured description for the blind in every instance. What is more, the consensus among the sighted was barely higher than that among the blind. Because motion devices are unfamiliar to the blind, the task I gave them involved some problem solving. Evidently, however, the blind not only figured out meanings for each line of motion, but as a group they generally came up with the same meaning at least as frequently as did sighted subjects.

Part 2

We have found that the blind understand other kinds of visual metaphors as well. One blind woman drew a picture of a child inside a heart – choosing that symbol, she said, to show that love surrounded the child. With Chang Hong Liu, a doctoral student from China, I have begun exploring how well blind people understand the symbolism behind shapes such as hearts that do not directly represent their meaning.

We gave a list of twenty pairs of words to sighted subjects and asked them to pick from each pair the term that best related to a circle and the term that best related to a square. For example, we asked: What goes with soft? A circle or a square? Which shape goes with hard?

All our subjects deemed the circle soft and the square hard. A full 94% ascribed happy to the circle, instead of sad. But other pairs revealed less agreement: 79% matched fast to slow and weak to strong, respectively. And only 51% linked deep to circle and shallow to square. (See Fig. 2.) When we tested four totally blind volunteers using the same list, we found that their choices closely resembled those made by the sighted subjects. One man, who had been blind since birth, scored extremely well. He made only one match differing from the consensus, assigning ‘far’ to square and ‘near’ to circle. In fact, only a small majority of sighted subjects – 53% – had paired far and near to the opposite partners. Thus, we concluded that the blind interpret abstract shapes as sighted people do.

剑4T2P1Lost for words

In the Native American Navajo nation which sprawls across four states in the American south-west, the native language is dying. Most of its speakers are middle-age or elderly. Although many students take classes in Navajo, the schools are run in English. Street sign, supermarket goods and even their own newspaper are all in English. Not surprisingly, linguists doubt that any native speakers of Navajo will remain in a hundred years’ time.

Navajo is far from alone. Half the world’s 6,800 languages are likely to vanish within two generations - that’s one language lost every ten days. Never before has the planet’s linguistic diversity shrunk at such a pace. “At the moment, we are heading for about three or four languages dominating the world”, says Mark Pagel, an evolutionary biologist at the University of Reading. “It’s a mass extinction, and whether we will ever rebound from the lost is difficult to know.

Isolation breeds linguistic diversity as a result, the world is peppered with languages spoken by only a few people. Only 250 language have more than a million speaker, and at least 3,000 have fewer than 2,500. It is not necessarily these small languages that are about to disappear. Navajo is considered endangered despite having 150,000 speakers. What makes a language endangered is not that the number of speakers, but how old they are. If it is spoken by children it is relatively safe. The critically endangered languages are those that are only spoken by the elderly, according to Michael Krauss, director of the Alassk Native Language Center, in Fairblanks.

Why do people reject the language of their parent? It begins with a crisis of confidence, when a small community find itself alongside a larger, wealthier society, says Nicholas Ostler of Britain’s Foundation for Endangered Languages, in Bath. ‘People lose faith in their culture’ he say. ‘When the next generation reaches their teens, they might not want to be induced into the old tradition.’

The change is not always voluntary. Quite often, governments try to kill off a minority language by banning its use in public or discouraging its use in school, all to promote national unity. The former US policy of running Indian reservation in English, for example, effectively put languages such as Navajo on the danger list. But Salikoko Mufwene, who chairs the Linguistics Department at the University of Chicago, argues that the deadliest weapon is not government policy but economic globalisation. ‘Native Americans have not lost pride in their language, but they have had to adapt to socioeconomic pressures’ he say. ‘They cannot refuse to speak English if most commercial activity is in English". But are languages worth saving? At the very least, there is a loss of data for the study of languages and their evolution, which relies on comparisons between languages, both living and dead. When an unwritten and unrecorded language disappears, it is lost to science.

Language is also intimately bond up with culture, so it may be difficult to reserve one without the other. ‘If a person shifts from Navajo to English, they lose something' Mufwene says. ‘Moreover, the loss of diversity may also deprive us of different ways of looking at the world’ say Pagel. There is mounting evidence that learning a language produces physiological changes in brain. ‘Your brain and mine are difference from the brain of someone, who speaks French, for instance’ Pagel says, and this could affect our thoughts and perceptions. ‘The patterns and connections we make among various concepts may be structured by the linguistic habits of our community.’

So despite linguists’ best efforts, many languages will disappear over the next century. But a growing interest in cultural identity may prevent the direst predictions from coming true. ‘The key to fostering diversity is for people to learn their ancestral tongue, as well as the dominant language’ says Doug Whalen, founder and president of the Endangered Language Fund in New Haven, Connecticut. ‘Most of these languages will not survive without a large degree of bilingualism’ he says. In New Zealand, classes for children have slowed the erosion of Maori and rekindled interest in the language. A similar approach in Hawaii has produce about 8000 new speakers of Polynesian languages in the past few years. In California, ‘apprentice’ programmes have provided life support to several indigenous languages. Volunteer 'apprentices' pair up with one of the last living speakers of Native American tongue to learn traditional skill such as basket weaving, with instruction exclusively in the endangered language. After about 300 hours of training they are generally sufficiently fluent to transmit the language to next generation. But Mufwene says that preventing a language dying out is not the same as giving it new life by using every day. ‘Preserving a language is more likely preserving fruits in a jar’ he says.

However, preservation can bring a language back from the dead. There are examples of languages that have survived in written form and then been revived by latter generations. But a written form is essential for this, so the mere possibility of revival has led many speakers of endangered languages to develop systems of writing where none existed before.

剑4T2P2ALTANERTIVE MEDICINE IN AUSTRALIA

The first students to study alternative medicine at university level in Australia began their four years, full- time course at the University of Technology, Sydney, in early 1994. Their course covered, among other therapies, acupuncture. The theory they learnt is based on the traditional Chinese explanation of this ancient, healing art that it can regulate the flow of ‘Qi’ or energy through pathways in the body. This course reflects how far some alternative therapies have come in their struggle for acceptance by the medical establishment.

Australia has been unusual in the Western world in having a very conservative attitude to natural or alternative therapies, according to Dr. Paul Laver a lecturer in Public Health at the University of Sydney. ‘We’ve had a tradition of doctors being fairly powerful and I guess they are pretty loath to allow any pretenders to their position to come into it.’ In many other industrialised countries orthodox and alternative medicines have worked ‘hand in glove’ for years. In Europe only orthodox doctors can prescribe herbal medicine. In German, plant remedies account for 10% of the national turnover of pharmaceuticals. Americans made more visit to alternative therapists than to orthodox doctors in 1990, and each year they spent about $US12 billion on therapies that have not been scientifically tested.

Disenchantment with orthodox medicine has seen the popularity of alternative therapies in Australia climb steadily during the past 20 years. In a 1983 national health survey, 1.9% of people said they had contacted a chiropractor, naturopath, osteopath, acupuncturist or herbalist in the two weeks prior to the survey. By 1990, this figure had risen to 2.6% of the population. The 550,000 consultations with alternative therapists reported in the 1990 survey represented about an eighth of the total number of consultations with medically qualified personnel covered by the survey, according to Dr Laver and colleagues writing in the Australian Journal of Public Health in 1993. ‘A better educated and less accepting public has become disillusioned with the experts in general, and increasingly skeptical about science and empirically based knowledge,’ they said. ‘The high standing of professionals, including doctors, has been eroded as a consequence’.

Rather than resisting or criticising this trend, increasing numbers of Australian doctors, particularly younger ones, are forming group practices with alternative therapists or taking courses themselves, particularly in acupuncture and herbalism. Part of the incentive was financial, Dr Laver said. ‘The bottom line is that most general practitioners are business people. If they see potential clientele going elsewhere, they might want to be able to offer a similar service.’

In 1993, Dr Laver and his colleagues published a survey of 289 Sydney people who attended eight alternative therapists’ practices in Sydney. These practices offered a wide range of alternative therapies from 25 therapists. Those surveyed had experienced chronic illnesses, for which orthodox medicine had been able to provide little relief. They commented that they liked the holistic approach of their alternative therapists and the friendly, concerned and detailed attention they had received. The cold, impersonal manner of orthodox doctors featured in the survey. An increasing exodus from their clinics, coupled with this and a number of other relevant surveys carried out in Australia, all pointing to orthodox doctors’ inadequacies, have led mainstream doctors themselves to begin to admit they could learn from the personal style of alternative therapists. Dr Patrick Store, President of the Royal College of General Practitioners; concurs that orthodox doctors could learn a lot about bedside manner and advising patients on preventative health from alternative therapists.

According to the Australia Journal of Public Health, 18% of patients visiting alternative therapists do so because they suffer from musculo-skeletal complaints, 12% suffer from digestive problems, which is only 1% more than those suffering from emotional problems. Those suffering from respiratory complaints represent 7% of their patients, and candida sufferers represent an equal percentage. Headache suffers and those complaining of general ill health represent 6% and 5% of patients respectively, and a further 4% see therapists for general health maintenance.

The survey suggested that complementary medicine is probably a better term than alternative medicine. Alternative medicine appears to be an adjunct; sought in times of disenchantment when conventional medicine seems not to offer the answer.

剑4T2P3 PLAY IS A SERIOUS BUSINESS

Does play help develop bigger, better brains? Bryant Furlow investigates.

Playing is a serious business. Children engrossed in a make-believe world, fox cubs play-fighting or kittens teaming a ball of string aren’t just having fun. Play may look like a carefree and exuberant way to pass the time before the hard work of adulthood comes along, but there’s much more to it than that. For a start, play can even cost animals their lives. Eighty percent of deaths among juvenile fur seals occur because playing pups fail to sport predators approaching. It is also extremely expensive in terms of energy. Playful young animals use around two or three per cent of energy cavorting, and in children that figure can be closer to fifteen per cent. ‘Even two or three per cent is huge,’ says John Byers of Idaho University. ‘You just don’t find animals wasting energy like that,’ he adds. There must be a reason.

But if play is not simply a developmental hiccup, as biologists once thought, why did it evolve? The latest idea suggests that play has evolved to build big brains. In other words, playing makes you intelligent. Playfulness, it seems, is common only among mammals, although a few of the larger-brained birds also indulge. Animals at play often use unique signs – tail-wagging in dogs, for example – to indicate that activity superficially resembling adult behavior is not really in earnest. In popular explanation of play has been that it helps juveniles develop the skills they will need to hunt, mate and socialise as adults. Another has been that it allows young animals to get in shape for adult life by improving their respiratory endurance. Both these ideas have been questioned in recent years.

Take the exercise theory. If play evolved to build muscle or as a kind of endurance training, then you would expect to see permanent benefits. But Byers points out that the benefits of increased exercise disappear rapidly after training stops, so many improvement in endurance resulting from juvenile play would be lost by adulthood. ‘If the function of play was to get into shape,’ says Byers, ‘the optimum time for playing would depend on when it was most advantageous for the young of a particular species to do so. But it doesn’t work like that.’ Across species, play tends to peak about halfway through the suckling stage and then decline.

Then there’s the skills- training hypothesis. At first glance, playing animals do appear to be practising the complex maneuvers they will need in adulthood. But a closer inspection reveals this interpretation as too simplistic. In one study, behavioural ecologist Tim Caro, from the University of California, looked at the predatory play of kittens and their predatory behaviour when they reached adulthood. He found that the way the cats played had no significant effect on their hunting prowess in later life.

Earlier this year, Sergio Pellis of Lethbridge University, Canada, reported that there is a strong positive link between brain size and playfulness among mammals in general. Comparing measurements for fifteen orders of mammals, he and his team found large brains (for a given body size) are linked to greater playfulness. The converse was also found to be true. Robert Barton of Durham University believes that, because large brains are more sensitive to developmental stimuli than smaller brains, they require more play to help mould them for adulthood. ‘I concluded it’s to do with learning, and with the importance of environmental data to the brain during development,’ he says.

According to Byers, the timing of the playful stage in young animals provides an important clue to what’s going on. If you plot the amount of time juvenile devotes to play each day over the course of its development, you discover a pattern typically associated with a ‘sensitive period’ – a brief development window during which the brain can actually be modified in ways that are not possible earlier or later in life. Think of the relative ease with which young children – but not infants or adults – absorb language. Other researchers have found that play in cats, rats and mice is at its most intense just as this ‘window of opportunity” reaches its peak.

‘People have not paid enough attention to the amount of the brain activated by plays,’ says Marc Bekoff from Colorado University. Bekoff studied coyote pups at play and found that the kind of behaviour involved was markedly more variable and unpredictable than that of adults. Such behaviour activates many different parts of the brain, he reasons. Bekoff likens it to a behavioural kaleidoscope, with animals at play jumping rapidly between activities. ‘They use behaviour from a lot of different contexts – predation, aggression, reproduction,’ he says. ‘Their developing brain is getting all sorts of stimulation.’

Not only is more of the brain involved in play that was suspected, but it also seems to activate higher cognitive processes. ‘There’s enormous cognitive involvement in play,’says Bekoff. He points out that play often involves complex assessments of playmates, ideas of reciprocity and the use of specialised signals and rules. He believes that play creates a brain that has greater behavioural flexibility and improved potential for learning later in life. The idea is backed up by the work of Stephen Siviy of Gettysburg College. Siviy studied how bouts of play affected the brain’s levels of particular chemical associated with the stimulation and growth of nerve cells. He was surprised by the extent of the activation. ‘Play just lights everything up,’ he says. By allowing link-ups between brain areas that might not normally communicate with each other, play may enhance creativity.

What might further experimentation suggest about the way children are raised in many societies today? We already know that rat pups denied the chance to play grow smaller brain components and fail to develop the ability to apply social rules when they interact with their peers. With schooling beginning earlier and becoming increasingly exam-orientated, play is likely to get even less of a look-in. Who knows what the result of that will be?

剑4T3P1 Micro-enterprise credit for street youth

Introduction: Although small-scale business training and credit programs have become more common throughout the world in the 1990s, relatively little attention has been paid to the need to direct such opportunities to young people. Even less attention has been paid to youth living on the street or in difficult circumstances. This was vividly demonstrated at the Micro-Credit Summit held in Washington in February last year. Much was said about the importance of extending small loans to poor women as a way of addressing world poverty, and incredible success stories were shared. However, the plenary statements, the conference documentation, and the declarations the delegates were asked to sign mentioned nothing about directing such programs to youth.

Yet, in many developing countries, youth under the age of 18 represent at least half of the population. Significant numbers of this age group do not live in the context of a typical family structure. Many do not have access to the formal structures of education which would provide them with the credentials for achieving a better future. The reality for the majority of these youth is that they have to earn money to support themselves, and often to support their families.

Over the past nine years, Street Kids International (SKI) has been working with partner organizations in Africa, Latin America and India to support the economic lives of street youth. The approaches have taken different forms: from apprenticeships to collectives to the promotion of individual businesses. There have also been various levels of success. The purpose of this paper is not to promote the adoption of any particular model, but to share some of the lessons SKI and our partners have learned. We view this is as a work in progress: we hope to contribute to a continuing dialogue amongst those interested in facilitating opportunities for street youth to meet their economic needs in healthy and sustainable ways.

Background

The "phenomenon" of street and working children is reflection of broad, systemic problems which are becoming better recognized and understood. Typically, children do not end up on the streets due to a single cause, but to a combination of factors: a dearth of adequately funded schools, the demand for income at home, the AIDS pandemic, family breakdown and violence. The street may be attractive to children as a place to find adventurous play and money. However, it is also a place where children are exposed, with little or no protection, to exploitive employment, drugs, urban crime, abuse, and unsafe sexual activity.

Children who work on the streets are generally involved in unskilled, labour intensive and low-capital tasks which require long hours, such as shining shoes, carrying goods, guarding or washing cars, and informal trading. Some may also earn income through begging, theft, sex work or drug trafficking.

At the same time, there are street youth who take pride in supporting themselves and their families and who often enjoy their work. Many children may choose entrepreneurship because it allows them a degree of independence, is less exploitive than many forms of paid employment, and is flexible enough to allow them to participate in other activities such as education and domestic tasks.

In the absence of a structured learning environment at school or significant involvement with their families at home, children learn life and business skills on the street. The street is both a positive and a negative socializing environment. In public places, work can quickly foster independence as youth become adept at asserting and defending themselves. In public places, work can also intersect with play and social interaction. Thus, there are opportunities for fun and a sense of belonging, as well as opportunities to organize into groups and to engage in collective activities. In many countries, particularly in Central America, groups of working children have successfully mobilized to defend their rights and interests.

However, there are common frustrations that street and working youth encounter across continents. They are concerned about the low social value that is generally placed on adolescents and youth. They tire of their self-respect being diminished through criticisms of their way of life and their values. They are resentful about the lack of opportunities for training which would allow entry into the labour force. They also feel that they face additional risks because they are young, including harassment by police, and a greater chance of having their money and assets stolen by strangers and by family members.

Street Business Partnerships

In the context of these conditions, common wherever urban poverty exists, SKI is convinced that services for street children must: respect the choices of the children; help them to reject exploitation and abuse; provide them with appropriate opportunities for learning; and recognize their economic lives.

SKI has worked with partner organizations in Latin America, Africa and India to develop innovative opportunities for street youth to earn income. Several of these joint initiatives, called 'Street Business Partnerships', have specifically involved credit:

l The SKI bicycle courier service first started in the Sudan. Participants in this enterprise were required to gradually pay for their bicycles from their wages. A similar program was taken up in Bangalore, India, in conjunction with the Ragpickers' Education & Development Scheme (REDS);

l  the shoe shine collective was a partnership program with the YWCA of Santa Domingo in the Dominican Republic. Participants in this small business collective were provided with loans to purchase shoe-shine boxes, coffee thermoses and candy display trays. They were also given a safe place to store their equipment, sources to purchase materials and supplies at discount rates, and facilities for individual savings plans;

l the youth skills enterprise initiative in Zambia is a joint program with the Zambia Red Cross Society and the YWCA of Zambia. Street youth are supported to start their own small businesses through business training, life skills training and access to credit. The young entrepreneurs also receive ongoing technical support from the program staff;

l  a candy wholesale business is currently being developed by MANTHOC in Peru. This program will train street youth in a variety of business, management and life skills. Loans will be available for purchasing products to sell.

Profile of children involved in SKI micro-business programs

Although there are variations among the partner agencies, in general these programs are directed towards marginalized youth, female and male, who: are between the ages of 12 and 18; are socially and/or economically disadvantaged; are currently out-of-school or are in the process of leaving or abandoning school altogether; lack access to economic resources and to pre-vocational training; and live in sub-standard or unsafe living conditions.

Conclusion: There is a need to recognize the importance of access to credit for impoverished young people seeking to fulfill economic needs. The provision of small loans to support the entrepreneurial dreams and ambitions of youth can be an effective means to help them change their lives. However, we believe that credit must be extended in association with other types of support that help participants develop critical life skills as well as productive businesses.

剑4T3P2 Volcanoes – earth shattering news

When Mount Pinatubo suddenly erupted on 9 June 1991, the power of volcanoes past and present again hit the headlines

Volcanoes are the ultimate earth-moving machinery. A violent eruption can blow the top few kilometers off a mountain, scatter fine ash practically all over the globe and hurt rock fragments into the stratosphere to darken the skies a continent away. But the classic eruption – cone-shaped mountain, big bang, mushroom cloud and surges of molten lava – is only a tiny part of a global story. Volcanism, the name given to volcanic processes, really has shaped the world. Eruptions have rifted continents, raised mountain chains, constructed islands and shaped the topography of the earth. The entire ocean floor has a basement of volcanic basalt.

Volcanoes have not only made the continents, they are also thought to have made the world’s first stable atmosphere and provided all the water for the oceans, rivers and ice-caps. There are now about 600 active volcanoes. Every year they add two or three cubic kilometers of rock to the continents. Imagine a similar number of volcanoes smoking away for the last 3,500 million years. That is enough rock to explain the continental crust.

What comes out of volcanic craters is mostly gas. More than 90% of this gas is water vapour from the deep earth: enough to explain, over 3,500 million years, the water in the oceans. The rest of the gas is nitrogen, carbon dioxide, sulphur dioxide, methane, ammonia and hydrogen. The quantity of these gases, again multiplied over 3,500 million years, is enough to explain the mass of the world’s atmosphere. We are alive because volcanoes provided the soil, air and water we need.

Geologists consider the earth as having a molten core, surrounded by a semi-molten mantle and a brittle, outer skin. It helps to think of a soft-boiled egg with a runny yolk, a firm but squishy white and a hard shell. If the shell is even slightly cracked during boiling, the white material bubbles out and sets like a tiny mountain chain over the crack – like an archipelago of volcanic islands such as the Hawaiian Islands. But the earth is so much bigger and the mantle below is so much halter.

Even though the mantle rocks are kept solid by overlying pressure, they can still slowly ‘flow’ like thick treacle. The flow, thought to be in the form of convection currents, is powerful enough to fracture the ‘eggshell’ of the crust into plates, and keep them bumping and grinding against each other, or even overlapping, at the rate of a few centimeters a year. These fracture zones, where the collisions occur, are where earthquakes happen. And, very often, volcanoes.

These zones are lines of weakness, or hot spots. Every eruption is different, but put at its simplest, where there are weaknesses, rocks deep in the mantle, heated to 1,350℃, will start to expand and rise. As they do so, the pressure drops, and they expand and become liquid and rise more swiftly.

Sometimes it is slow: vast bubbles of magma – molten rock from the mantle – inch towards the surface, cooling slowly, to show through as granite extrusions (as on Skye, or the Great Whin Sill, the lava dyke squeezed out like toothpaste that carries part of Hadrian’s Wall in northern England).

Sometimes – as in Northern Ireland, Wales and the Karoo in South Africa – the magma rose faster, and then flowed out horizontally on to the surface in vast thick sheets. In the Deccan plateau in western India, there are more than two million cubic kilometers of lava, some of it 2,400 meters thick, formed over 500,000 years of slurping eruption.

Sometimes the magma moves very swiftly indeed. It does not have time to cool as it surges upwards. The gases trapped inside the boiling rock expand suddenly, the lava glows with heat, it begins to froth, and it explodes with tremendous force. Then the slightly cooler lava following it begins to flow over the lip of the crater. It happens on Mars, it happened on the moon, it even happens on some of the moons of Jupiter and Uranus. By studying the evidence, vulcanologists can read the force of the great blasts of the past. Is the pumice light and full of holes? The explosion was tremendous. Are the rocks heavy, with huge crystalline basalt shapes, like the Giant’s Causeway in Northern Ireland? It was a slow, gentle eruption.

The biggest eruption are deep on the mid-ocean floor, where new lava is forcing the continents apart and widening the Atlantic by perhaps five centimeters a year. Look at maps of volcanoes, earthquakes and island chains like the Philippines and Japan, and you can see the rough outlines of what are called tectonic plates – the plates which make up the earth’s crust and mantle. The most dramatic of these is the Pacific ‘ring of fire’ where there have the most violent explosions – Mount Pinatubo near Manila, Mount St Helen’s in the Rockies and El Chichón in Mexico about a decade ago, not to mention world-shaking blasts like Krakatoa in the Sunda Straits in 1883.

But volcanoes are not very predictable. That is because geological time is not like human time. During quiet periods, volcanoes cap themselves with their own lava by forming a powerful cone from the molten rocks slopping over the rim of the crater; later the lava cools slowly into a huge, hard, stable plug which blocks any further eruption until the pressure below becomes irresistible. In the case of Mount Pinatubo, this took 600 years.

Then, sometimes, with only a small warning, the mountain blows its top. It did this at Mont Pelée in Martinique at 7.49 a.m. on 8 May, 1902. Of a town of 28,000, only two people survived. In 1815, a sudden blast removed the top 1,280 meters of Mount Tambora in Indonesia. The eruption was so fierce that dust thrown into the stratosphere darkened the skies, canceling the following summer in Europe and North America. Thousands starved as the harvest failed, after snow in June and frosts in August. Volcanoes are potentially world news, especially the quiet ones.

剑4T3P2 Obtaining Linguistic Data

【A】Many procedures are available for obtaining data about a language. They range from a carefully planned, intensive field investigation in a foreign country to a casual introspection about one’s mother tongue carried out in an armchair at home.

【B】In all cases, someone has to act as a source of language data – aninformant. Informants are (ideally) native speakers of a language, who provide utterances for analysis and other kinds of information about the language (e.g. translations, comments about correctness, or judgments on usage). Often, when studying their mother tongue, linguists act as their own informants, judging the ambiguity, acceptability, or other properties of utterances against their own intuitions. The convenience of this approach makes it widely used, and it is considered the norm in the generative approach to linguistics. But a linguist’s personal judgments are often uncertain, or disagree with the judgments of other linguists, at which point resource is needed to more object methods of enquiry, using non-linguists as informants. The later procedure is unavoidable when working on foreign languages, or child speech.

【C】Many factors must be considered when selecting informants – whether one is working with single speakers (a common situation when languages have not been described before), two people interacting, small groups or large-scale samples. Age, sex, social background and other aspects of identity are important, as these factors are known to influence the kind of language used. The topic of conversation and the characteristics of the social setting (e.g. the level of formality) are also highly relevant, as are the personal qualities of the informants (e.g. their fluency and consistency). For larger studies, scrupulous attention has been paid to the sampling theory employed, and in all cases, decisions have to be made about the best investigative techniques to use.

【D】Today, researchers often tape-record informants. This enables the linguist’s claims about the language to be checked, and provides a way of making those claims more accurate (‘difficult’ pieces of speech can be listened to repeatedly). But obtaining naturalistic, good-quality data is never easy. People talk abnormally when they know they are being recorded, and sound quality can be poor. A variety of tape-recording procedures have thus been devised to minimise the ‘observer’s paradox’ (how to observe the way people behave when they are not being observed). Some recordings are made without the speakers being aware of the fact – a procedure that obtains very natural data, though ethical objections must be anticipated. Alternatively, attempts can be made to make the speaker forget about the recording, such as keeping the tape recorder out of sight, or using radio microphones. A useful technique is to introduce a topic that quickly involves the speaker, and stimulates a natural language style (e.g. asking older informants about how times have changed in their locality).

【E】An audio tape recording does not solve all the linguist’s problems, however. Speech is often unclear and ambiguous. Where possible, therefore, the recording has to be supplements by the observer’s written comments on the non-verbal behaviour of the participants, and about the context in general. A facial expression, for example, can dramatically alter the meaning of what is said. Video recordings avoid these problems to a large extent, but even they have limitations (the camera cannot be everywhere), and transcription always benefits from any additional commentary provided by an observer.

【F】Linguists also make great use of structured sessions, in which they systematically ask their informants for utterances that describe certain actions, objects or behavious. With a bilingual informant, or through use of an interpreter, it is possible to use translation technique (‘How do you say table in your language?’). A large number of points can be covered in a short time, using interview work-sheets and questionnaires. Often, the researcher wishes to obtain information about just a single variable, in which case a restricted set of questions may be used: a particular feature of pronunciation, for example, can be elicited by asking the informant to say a restricted set of words. There are also several direct methods of elicitation, such as asking informants to fill in the blanks in a substitution frame (e.g. 'I ___ see a car.'), or feeding them the wrong stimulus for correction (‘Is it possible to say I no can see?’).

【G】A representative sample of language, complied for the purpose of linguistic analysis, is known as a corpus. A corpus enables the linguist to make unbiased statements about frequency of usage, and it provides accessible data for the use of different researchers. Its range and size are variable. Some corpora attempt to cover the language as a whole, taking extracts from many kinds of text; others are extremely selective, providing a collection of material that deals only with a particular linguistic feature. The size of the corpus depends on practical factors, such as the time available to collect, process and store the data: it can take up to several hours to provide an accurate transcription of a few minutes of speech. Sometimes a small sample of data will be enough to decide a linguistic hypothesis; by contrast, corpora in major research projects can total millions of words. An important principle is that all corpora, whatever their size, are inevitably limited in their coverage, and always need to be supplemented by data derived from the intuitions of native speakers of the language, though either introspection or experimentation.

剑4T4P1 How Much Higher? How Much Faster?

—Limits to human sporting performance are not yet in sight—

Since the early years of the twentieth century, when the International Athletic Federation began keeping records, there has been a steady improvement in how fast athletes run, how high they jump and how far they are bale to hurl massive objects, themselves included, through space. For the so-called power events –that require a relatively brief, explosive release of energy, like the 100-metre sprint and the long jump-times and distances have improved ten to twenty percent. In the endurance events the results have been more dramatic. At the 1908 Olympics, John Hayes of the U.S. team ran to marathon in a time of 2:55:18. In 1999, Morocco’s Khalid Khannouchi set a new world record of 2:05:42, almost thirty percent faster.

No one theory can explain improvements in performance, but the most important factor has been genetics. ‘The athlete must choose his parents carefully,’ says Jesus Dapena, a sports scientist at Indiana University, invoking an oft-cited adage. Over the past century, the composition of the human gene pool has not changed appreciably, but with increasing global participation in athletics-and greater rewards to tempt athletes-it is more likely that individuals possessing the unique complement of genes for athletic performance can be identified early. ‘Was there someone like [sprinter] Michael Johnson in the 1920s?’ Dapena asks. ‘I’m sure there was, but his talent was probably never realized.’

Identifying genetically talented individuals is only the first step. Michael Yessis, an emeritus professor of Sports Science at California State University at Fullerton, maintains that ‘genetics only determines about one third of what an athlete can do. But with the right training we can go much further with that one third than we’ve been going.’ Yesis believes that U.S. runners, despite their impressive achievements, are ‘running on their genetics’. By applying more scientific methods, ‘they’re going to go much faster’. These methods include strength training that duplicates what they are doing in their running events as well as plyometrics, a technique pioneered in the former Soviet Union.

Whereas most exercises are designed to build up strength or endurance, plyometrics focuses on increasing power-the rate at which an athlete can expend energy. When a sprinter runs, Yesis explains, her foot stays in contact with the ground for just under a tenth of a second, half of which is devoted to landing and the other half to pushing off. Plyometric exercises help athletes make the best use of this brief interval.

Nutrition is another area that sports trainers have failed to address adequately. ‘Many athletes are not getting the best nutrition, even though supplements,’ Yessis insists. Each activity has its own nutritional needs. Few coaches, for instance, understand how deficiencies in trace minerals can lead to injuries.

Focused training will also play a role in enabling records to be broken. ‘If we applied the Russian training model to some of the outstanding runners we have in this country,’ Yessis asserts, ‘they would be breaking records left and right.’ He will not predict by how much, however: ‘Exactly what the limits are it’s hard to say, but there will be increases even if only by hundredths of a second, as long as our training continues to improve.’

One of the most important new methodologies is biomechanics, the study of the body in motion. A biomechanic films an athlete in action and then digitizes her performance, recording the motion of every joint and limb in three dimensions. By applying Newton’s law to these motions, ‘we can say that this athlete’s run is not fast enough; that this one is not using his arms strongly enough during take-off,’ says Dapena, who uses these methods to help high jumpers. To date, however, biomechanics has made only a small difference to athletic performance.

Revolutionary ideas still come from the athletes themselves. For example, during the 1968 Olympics in Mexico City, a relatively unknown high jumper named Dick Fosbury won the gold by going over the bar backwards, in complete contradiction of all the received high-jumping wisdom, a move instantly dubbed the Fosbury flop. Fosbury himself did not know what he was doing. That understanding took the later analysis of biomechanics specialists. Who put their minds to comprehending something that was too complex and unorthodox ever to have been invented through their own mathematical simulations. Fosbury also required another element that lies behind many improvements in athletic performance: an innovation in athletic equipment. In Fosbury’s case, it was the cushions that jumpers land on. Traditionally, high jumpers would land in pits filled with sawdust. But by Fosbury’s time, sawdust pits had been replaced by soft foam cushions, ideal for flopping.

In the end, most people who examine human performance are humbled by the resourcefulness of athletes and the powers of the human body. ‘Once you study athletics, you learn that it’s a vexingly complex issue,’ says John S.Raglin, a sports psychologist at Indiana University. ‘Core performance is not a simple or mundane thing of higher, faster, longer. So many variables enter into the equation, and our understanding in many cases is fundamental. We’re got a long way to go.’ For the foreseeable future, records will be made to be broken.

 

剑4T4P2 The Nature and Aims of Archaeology

Archaeology is partly the discovery of the treasures of the past, partly the careful work of the scientific analyst, partly the exercise of the creative imagination. It is toiling in the sun on an excavation in the Middle-East, it is working with living Inuit in the snows of Alaska, and it is investigating the sewers of Roman Britain. But it is also the painstaking task of interpretation, so that we come to understand what these things mean for the human story. And it is the conservation of the world's cultural heritage against looting and careless harm.

Archaeology, then, is both a physical activity out in the field, and an intellectual pursuit in the study or laboratory. That is part of its great attraction. The rich mixture of danger and detective work has also made it the perfect vehicle for fiction writers and film-makers, from Agatha Christie with Murder in Mesopotamia to Stephen Spielberg with Indiana Jones. However far from reality such portrayals are, they capture the essential truth that archaeology is an exciting quest — the quest for knowledge about ourselves and our past.

But how does archaeology relate to disciplines such as anthropology and history, that are also concerned with the human story? Is archaeology itself a science? And what are the responsibilities of the archaeologist in today's world?

Anthropology, at its broadest, is the study of humanity — our physical characteristic as animals and our unique non-biological characteristics that we call culture. Culture in this sense includes what the anthropologist, Edward Tylor, summarized in 1871 as ‘knowledge, belief, art, morals, custom and any other capabilities and habits acquired by man as a member of society’. Anthropologists also use the term ‘culture’ in a more restricted sense when they refer to the ‘culture’ of a particular society, meaning the nonbiological characteristics unique to that society, which distinguish it from other societies. Anthropology is thus a broad discipline — so broad that it is generally broken down into three smaller disciplines: physical anthropology, cultural anthropology and archaeology.

Physical anthropology, or biological anthropology as it is also called, concerns the study of human biological or physical characteristics and how they evolved. Cultural anthropology — or social anthropology — analyses human culture and society. Two of its branches are ethnography (the study at first hand of individual living cultures) and ethnology (which sets out to compare cultures using ethnographic evidence to derive general principles about human society).

Archaeology is the ‘past tense of culture anthropology’. Whereas cultural anthropologists will often base their conclusions on the experience of living within contemporary communities, archaeologists study past societies primarily through their material remains the buildings, tools and other artifacts that constitutes what is known as the material culture left over from former societies.

Nevertheless, one of the most important tasks for the archaeologist today is to know how to interpret material culture in human terms. How were those pots used? Why are some dwellings round and others square? Here the methods of archaeology and ethnography overlap. Archaeologists in recent decades have developed ‘ethnography’, where, like ethnographers, they live among contemporary communities, but with the specific purpose of learning how such societies use material culture — how they make their tools and weapons, why they build their settlements where they do, and so on. Moreover, archaeology has an active role to play in the field of conservation. Heritage studies constitutes a developing field, where it is realized that the world’s cultural heritage is a diminishing resource which holds different meanings for different people. If, then archaeology deals with the past, in what way does it differ from history? In the broadest sense, just as archaeology is an aspect of anthropology, so too is it a part of history — where we mean the whole history of humankind from its beginnings over three million years ago. Indeed, for more than ninety-nine percent of that huge span of time, archaeology — the study of past material culture — is the only significant source of information. Conventional historical sources begin only with the introduction of written records around 3000 BC in western Asia, and much later in most other parts of the world.

A commonly drawn distinction is between pre-history, i.e. the period before written records — and history in the narrow sense, meaning the study of the past using written evidence. To archaeology, which studies all cultures and periods, whether with or without writing, the distinction between history and pre-history is a convenient dividing line that recognizes the importance of the written word, but in no way lessens the importance of the useful information contained in oral histories.

Since the aim of archaeology is the understanding of humankind, it is a humanistic study, and since it deals with the human past, it is a historical discipline. But it differs from the study of written history in a fundamental way. The material the archaeologist finds does not tell us directly what to think. Historical records make statements, offer opinions and pass judgments. The objects the archaeologists discover, on the other hand, tell us nothing directly in themselves. In this respect, the practice of the archaeologist is rather like that of the scientist, who collects data, conducts experiments, formulates a hypothesis, tests the hypothesis against more data, and then, in conclusion, devises a model that seems best to summarize the pattern observed in the data. The archaeologist has to develop a picture of the past, just as the scientist has to develop a coherent view of the natural world.

剑4T4P3 The problem of Scarce Resources

Section A

The problem of how health-care resources should be allocated or apportioned, so that they are distributed in both the most just and most efficient way, is not a new one. Every health system in an economically developed society is faced with the need to decide (either formally or informally) what proportion of the community’s total resources should be spent on health-care; how resources are to be apportioned; what diseases and disabilities and which forms of treatment are to be given priority; which members of the community are to be given special consideration in respect of their health needs; and which forms of treatment are the most cost-effective.

Section B

What is new is that, from the 1950s onwards, there have been certain general changes in outlook about the finitude of resources as a whole and of health-care resources in particular, as well as more specific changes regarding the clientele of health-care resources and the cost to the community of those resources. Thus, in the 1950s and 1960s, there emerged an awareness in Western societies that resources for the provision of fossil fuel energy were finite and exhaustible and that the capacity of nature or the environment to sustain economic development and population was also finite. In other words, we became aware of the obvious fact that there were ‘limits to growth’. The new consciousness that there were also severe limits to health-care resources was part of this general revelation of the obvious. Looking back, it now seems quite incredible that in the national health systems that emerged in many countries in the years immediately after the 1939-45 World War, it was assumed without question that all the basic health needs of any community could be satisfied, at least in principle; the ‘invisible hand’ of economic progress would provide.

Section C

However, at exactly the same time as this new realization of the finite character of health-care resources was sinking in, an awareness of a contrary kind was developing in Western societies: that people have a basic right to health-care as a necessary condition of a proper human life. Like education, political and legal processes and institutions, public order, communication, transport and money supply, health-care came to be seen as one of the fundamental social facilities necessary for people to exercise their other rights as autonomous human beings. People are not in a position to exercise personal liberty and to be self-determining if they are poverty-stricken, or deprived of basic education, or do not live within a context of law and order. In the same way, basic health-care is a condition of the exercise of autonomy.

Section D

Although the language of ‘rights’ sometimes leads to confusion, by the late 1970s it was recognized in most societies that people have a right to health-care (though there has been considerable resistance in the United States to the idea that there is a formal right to health-care). It is also accepted that this right generates an obligation or duty for the state to ensure that adequate health care resources are provided out of the public purse. The state has no obligation to provide a health-care system itself, but to ensure that such a system is provided. Put another way, basic health-care is now recognized as a ‘public good’, rather than a ‘private good’ that one is expected to buy for oneself. As the 1976 declaration of the World Health Organisation put it: ‘The enjoyment of the highest attainable standard of health is one of the fundamental rights of every human being without distinction of race, religion, political belief, economic or social condition.’ As has just been remarked, in a liberal society basic health is seen as one of the indispensable conditions for the exercise of personal autonomy.

Section E

Just at the time when it became obvious that health-care resources could not possibly meet the demands being made upon them, people were demanding that their fundamental right to health-care be satisfied by the state. The second set of more specific changes that have led to the present concern about the distribution of health-care resources stems from the dramatic rise in health costs in most OECD countries, accompanied by large-scale demographic and social changes which have meant, to take one example, that elderly people are now major(and relatively very expensive)consumers of health-care resources. Thus in OECD countries as a whole, health costs increased from 3.8% of GDP in 1960 to 7% of GDP in 1980, and it has been predicted that the proportion of health costs to GDP will continue to increase.(In the US the current figure is about 12% of GDP, and in Australia about 7.8% of GDP.)

As a consequence, during the 1980s a kind of doomsday scenario (analogous to similar doomsday extrapolations about energy needs and fossil fuels or about population increases) was projected by health administrator, economists and politicians. In this scenario, ever-rising health costs were matched against static or declining resources.