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A．Programs can be transmitted live internationally.B．Astronauts have regularly sent te
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The events of Sept. 11 have ratcheted up security at American airports to the highest level ever, according to a spokesman for Transportation Secretary Norman Mineta. But to say there is plenty of room for improvement puts it mildly:
Hundreds of employees with access to high-security areas at 15 U.S. airports have been arrested or indicted by federal law enforcement officials for using phony Social Security numbers, lying about criminal convictions or being in the United States illegally. None of those arrested had terrorist links, but some aviation experts said the workers were in a position to help smuggle weapons or bombs aboard aircraft if they had wanted.
Tests ordered by President Bush and conducted by federal agents at 32 airports between November and February, when airports were on highest alert, showed that Security screeners failed to detect knives 70% of the time, guns 30% of the time and simulated explosives 60% of the time.
Two members of the House Transportation Committee are pushing to reverse the administration's opposition to arming pilots because groups representing pilots are insisting that their members need to be armed as a last line of defense.
Attorney General John Ashcroft said the arrests of hundreds of airport employees showed that the system of background checks—done piecemeal by airlines, private contractors and others—needs tightening. That much is painfully obvious. What isn't clear is why the system was so porous (有漏洞的) to begin with and why it wasn't immediately tightened after that infamous Tuesday in September.
Some people in the industry wisely have suggested that all airport workers be required to pass through the same metal detectors and other Security checks as flight crews do. Congress has ordered the new Transpiration Security Administration to find ways to enact just such a requirement. Unfortunately, no deadline has been set, in part because federal officials are preoccupied with getting thousands of new baggage screeners in place by Nov. 19---when the feds take over airport security—and installing bomb—detection equipment in all airports by the end of the year.
Plainly, those two goals are critical. But it would be a mistake to give low priority to fixing other gaping holes in the nation's airport security net. If the federal crackdown is going to be effective, it needs to be comprehensive.
The possible mason for hundreds of airport employees being arrested might be one of the following except ______.
When an invention is made, the inventor has three possible 【C1】______ of action open to him: he can give the invention to file world by publishing it, keep the idea 【C2】______ , or patent it.
A 【C3】______ patent is the result of a bargain 【C4】______ between an inventor and the state, but the inventor gets a limited period of monopoly and publishes full details of his invention to the public after that period 【C5】______ .
Only in the most exceptional circumstances 【C6】______ the lifespan of a patent 【C7】______ to alter this normal process of events
The longest extension ever 【C8】______ was to Georges Valensi; his 1939 patent for color TV receiver circuit was extended until 1971 because for most of the patent's normal life there was no color TV to 【C9】______ and thus no hope for reward for the invention.
Because a patent remains permanently 【C10】______ after it has terminated, the shelves of the library attached to the 【C11】______ office contain details of literally millions of ideas that are free for anyone to use and, if 【C12】______ than half a century, sometimes even re-patent. Indeed, patent experts often advise anyone 【C13】______ to avoid the high cost of conducting a search through【C14】______ patents that the one sure way of violation of any other inventor's right is to plagiarize a dead patent. Likewise, because publication of an idea in any other form【C15】______ invalidates further patents on that idea, it is traditionally 【C16】______ to take ideas from other areas of print. Much modem technological advance is【C17】______ on these presumptions of legal security.
Anyone closely 【C18】______ in patents and inventions soon learns that most "new" ideas are, in fact, as old as the hills. It is theft reduction to commercial practice, either through necessity or dedication, or through the availability of new technology,【C19】______ makes news and money. The basic patent for the theory for magnetic recording dates back to 1886. Many of the original ideas behind television originate 【C20】______ the late 19th and early 20th century. Even the Volkswagen rear engine car was anticipated by a 1904 patent for a cart with the horse at the rear.
【C1】______
Without water no living thing can survive, and one feature of the true desert landscape is the absence of vegetation. With little rain and hardly any vegetation the land suffers under the sun. There are virtually no clouds or trees to protect the earth's surface and it can be burning hot. Under the sun, soils break up and crack. Wind and torrential rain sweep away and erode the surface further. Eight million square kilometers of the world's land surface is desert. Throughout history deserts have been expanding and retreating again. Cave paintings show that parts of the Sahara Desert were green and fertile about 10,000 years ago, and even animals like elephants and giraffes roamed the land. Fossil and dunes found in fertile and damp parts of the world show that these areas were once deserts. But now the creation of new desert areas is happening on a colossal scale. Twenty million square kilometers, an area twice the size of Canada, is at a high to very high risk of becoming desert. With a further 1.25 million square kilometers under moderate risk, an area covering 30% of the earth's land surface is desert, becoming desert, or in danger of becoming desert. The rate of growth of deserts is alarming. The world's drylands which are under threat include some of the most important stock-rearing and wheat-growing areas and are the homes of 600--700 million people. These regions are becoming deserts at the rate of more than 58, 000 square kilometers a year or 44 hectares a minute. In North Africa at least 100,000 hectares of cropland am lost each year. At this rate there is a high risk that we will be confined to living on only 50% of this planet's land surface within one more century unless we am able to do something about it.
What does the passage tell us about rainfall in the desert？
There is no question that the old style. of air pollution could kill people. In one week following the infamous "peasouper" fog in December 1952, 4,700 people died in London. Most of these people were elderly and already had heart or lung diseases. A series of these killer fogs eventually led to the British Passing the Clean Air Act which restricted the burning of coal.
Fortunately the effect of smog on the lungs is not so dramatic. Scientists have now conducted a number of laboratory experiments in which volunteers are exposed to ozone inside a steel chamber for a few hours. Even at quite low concentrations there is a reversible fall in lung function, an increase in the irritability of the lungs and evidence of airway inflammation (发炎) . Although irritable and inflamed lungs are particularly seen in people with asthma (哮喘) and other lung diseases, these effects of ozone also occur in healthy subjects. Similar changes are also seen after exposure to nitrogen dioxide, although there is some disagreement about the concentration at which they occur.
Other studies have found that people living in areas with high levels of pollution have more symptoms and worse lung function than those living in areas with clean air. Groups of children attending school camps show falls in lung function even at quite low concentrations of ozone. There is also a relationship between ozone levels and hospital admissions for asthma, both in North America and Australia. It is suspected that long-term exposure to smog may result in chronic bronchitis (支气管炎) and emphysema (肺气肿), but this has yet to be proven.
Recently an association has been found between the levels of particles in the air and death rates in North American cities. The reason for this association is not understood and as vet there is no evidence this occurs in Australia. However, we do know that hazy days are associated with more asthma attacks in children.
Which of the following is NOT the result of laboratory experiments？
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