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Migration is usually defined as "permanent or semi-permanent change of residence." This broad definition, of course, would include a move across the street or across a city. Our concern is with movement between nations, not with internal migration within nations, although such movements often exceed international movements in volume. Today, the motives of people who move short distances are very similar to those of international migrants.
Students of human migration speak of "push" and "pull" factors, which influence an individual's decision to move from one place to another. Push factors are associated with the place of origin. A push factor can be as simple and mild a matter as difficulty in finding a suitable job, or as traumatic as war, or severe famine. Obviously, refugees who leave their homes with guns pointed at their heads are motivated almost entirely by push factors (although pull factors do influence their choice of destination).
Pull factors are those associated with the place of destination. Most often these are economic, such as better job opportunities or the availability of good land to farm. The latter was an important factor in attracting settlers to the United States during the 19th century. In general, pull factors add up to an apparently better chance between several attractive potential destinations. The deciding factor might be a non economic consideration such as the presence of relatives, friends, or at least fellow countrymen already established in the new place who are willing to help the newcomers settle in. Considerations of this sort lead to the development of migration flow.
Besides push and pull factors, there are what the sociologists call "intervening obstacles", Even if push and/or pull factors are very strong they still may be outweighed by intervening obstacles, such as the distance of the move, the trouble and cost of moving, the difficulty of entering the new country, and the problem likely to be encountered on arrival.
The decision to move is also influenced by "personal factors" of the potential migrant. The same push pull factors and obstacles operate differently on different people, sometimes because they are at different stages of their lives, or just because of their varying abilities and personalities. The prospect of packing up everything and moving to a new and perhaps very strange environment may appear interesting and challenging, to an unmarried young man and appallingly difficult to a slightly older man with a wife and small kids. Similarly, the need to learn a new language and customs may excite one person and frighten another.
Regardless of why people move, migration of large numbers of people causes conflict. The United States and other western countries have experienced adjustment problems with each new wave of immigrants. The newest arrivals are usually given the lowest-paid jobs and are resented by native people who may have to compete with them for those jobs. It has usually taken several decades for each group to be accepted into the mainstream of society in the host country.
What was indicated from the arrangement of the seat？
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As president of the American Board of Professional Psychology, he's heard the complaint from working people over and over again: too many bosses.
If a shirt manufacturer's customers are returning merchandise because the collars are crooked, he said, the people who make the shirts are more likely than management to identify the problem quickly if they get together to talk about it.
But if the boss comes on as an adversary, bawling them out for bad work and threatening to or actually firing some, the remaining workers will probably react angrily and work will suffer.
He recalled an insurance company in Hartford, Conn. that got about 50,000 pieces of mail every morning. One person was assigned to slit the envelopes starting at 6 a.m. When a meeting was called to discuss the frequent turnover of employees in that job, one worker suggested that the starting hour be changed to 7:30, and the one person to a team of four or five.
The solution worked, Marrow said, because one person was no longer stuck with a boring and lonely job for four to five hours. The work got done in one hour, and the people who did it were then given more varied and interesting clerical duties the remainder of the day.
That's called "job enrichment". More American companies are turning to it because surveys show it is No. 1 on employees' lists of importance: "Not wages, not hours. They are fifth, sixth, seventh", Marrow said.
Job enrichment and employee participation gain the support of top organizations because they arc good for production and reduce staff turnover, he said. For employees who have not yet discovered they can actually influence management, he suggests: if you have a problem or objectives that will be good for the company, first discuss them with your coworkers.
The author's chief purpose is ______.
The introduction of non-native "exotic" species is now seen as a major threat to biodiversity. In 1825, a particularly vigorous female clone of itadori (called Japanese knotweed) was introduced into Holland and later distributed throughout Europe by the plant collector and nurseryman, Von Seybold. British gardeners loved it and by 1886 it was eyen found growing on cinder tips in South Wales. By the turn of the century, the plant had colonized many other sites, and gardeners were advised against planting it in shrubberies. By 1994, it Was almost everywhere — railways, riversides, hedgerows, cemeteries — swamping a wide range of habitats and displacing rare species. Botanists' fears that the plant is still spreading and may yet colonize other new habitats have generated recent attempts to eradicate it by mechanical and chemical methods, all in vain as yet.
The evidence stacked against Japanese knotweed is damning. But there is a deep anxiety that behind the desire to correct human ecological cook-ups often manifested as a passion to save endangered species and vulnerable ecosystems — is a thinly disguised xenophobia: that we are simply seeing yet another form. of ecological imperialism which defines what is "natural" .based on human preferences.
But whatever our reaction to "problem" or alien species is, it must involve moral decisions. And who should make such decisions and to what degree they are accountable must also be up for review. The conclusions of scientists and other sections of society may differ vastly about what to do about the introduced animals. And plants. For example, the scheme to control rabbits in Australia by deliberately spreading the disease myxomatosis was a success in that huge numbers of rabbits were wiped out for the greater good — the "health" of Australian ecosystems. But would inflicting such a horrifically slow agonizing death on sentient creatures win popular support if it were proposed today？
Scientists of biodiversity are by their very nature concerned with the organization of species into systems and not necessarily with the interests and well being of individual, particularly those that are seen as a threat to the maintenance of those systems. Yet there is a growing feeling for the democratization of decisions concerning nonhuman life. The movement towards environmental values must surely involve a movement away from imperialism and a search for a relationship with nature as it truly is, rather than as we would design it. Then, when our lawns have long disappeared, we may yet come to honor the humble dandelion.
In the author's opinion, the attempt to eradicate the Japanese knotweed ______.
______ me most was that the young boy who had lost both arms in an accident could handle a
Air pollution involves the release into the atmosphere【C1】______ gases, finely divided solids, or finely dispersed liquid aerosols at rates that【C2】______ the capacity of the atmosphere to dissipate them or to dispose【C3】______ them through incorporation into solid or【C4】______ layers of the biosphere. Air pollution【C5】______ a variety of causes, not all of which are【C6】______ human control. Dust storms in desert areas and smoke from forest and grass fires【C7】______ to chemical and particulate pollution of the air. Forest fires that swept the state of Victoria, in Australia, in 1939 caused【C8】______ air pollution in Queensland, more than 2,000 miles (3,000 kilometres) away. Dust blown from the Sahara has been【C9】______ in West Indian islands. The discovery of 【C10】______ in Antarctica, where they have never been used, suggests the【C11】______ to which aerial transport can carry pollutants from one place to another. Probably the most important natural【C12】______ of air pollution is volcanic activity , which at times【C13】______ great amounts of ash and toxic【C14】______ into the atmosphere. The eruptions of such volcanoes as Krakatoa, in the East Indies, Mt. St. Helens, in Washington, and Katmai, in Alaska, have been 【C15】______ to 【C16】______ climatic changes.
Air pollution may affect humans directly, causing a smarting of the【C17】______ or coughing. More indirectly, the effects of air pollution are experienced at【C18】______ distances from the source, as, for example, the fallout of tetraethy lead from urban automobile【C19】______ which has been observed in the oceans and on the Greenland ice sheet. Still【C20】______ directly experienced are the possible effects of air pollution on global climates.
【C1】
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