This week marks the 10th anniversary of the Alar apple scare, in which many American consumers were driven into a panic following the release of a report by an environmental organization claiming that apples containing the chemical Alar posed a serious health threat to preschoolers. The report was disseminated through a PR (Problem Report) campaign and bypassed any legitimate form of scientific peer re view. Introduced to the American public by CBS "60 Minutes," the unsubstantiated claims in the report led some school districts to remove apples from their school lunch programs and unduly frightened conscientious parents trying to develop good eating habits for their children.Last month, Consumers Union released a report wanting consumers of the perils of consuming many fruits and vegetables that frequently contained "unsafe" levels of pesticide residues. This was especially true for children, they claimed, lake its predecessor 10 years earlier, the Consumers Union report received no legitimate scientific peer review and the public’s first exposure to it was through news coverage.Not only does such reporting potentially drive children for consuming healthful fruits and vegetables, the conclusions were based on a misleading interpretation of what constitutes a "safe" level of exposure. Briefly, the authors used values known as the "chronic reference doses," set by the U.S. environmental Protection Agency, as their barometers of safely. Used appropriately, thee levels represent the maximum amount of pesticide that could be consumed daily for life without concern. For a 70-year lifetime, for example, consumers would have to ingest this ’average amount of pesticide every day for more than 25,000 days. It is clear, as the report points out, that there are days on which kids may be exposed to more; it is also clear that there are many more days when exposure is zero. Had the authors more appropriately calculated the cumulative exposures for which the safety standards axe meant to apply, there would have been no risks and no warnings.Parents should feel proud, rather than guilty, of providing fruits and vegetables for their children. It is well established that a diet rich in such foods decreases the risk of heart disease and cancer. Such benefits dramatically overwhelm the theoretical risks of tiny amounts of pesticides in food. So keep serving up the peaches, apples, squash, grapes and pears. In the Alar apple scare, many Americans were frightened because ()
A. scientists warned that apples were dangerous
B. many school children became iii after eating apples
C. it was reported that apples were harmful to health
D. apples were discovered to have too much pesticide
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I want to talk about all these points in ______ order of importance.
A. declining
B. descending
C. plunging
D. falling
Traffic statistics paint a gloomy picture. To help solve their traffic woes, some rapidly growing U.S. cities have simply built more roads. But traffic experts say building more roads is a quick-fix solution that will not alleviated the traffic problem in the long nm. Soaring land costs, increasing concern over social and environmental disruptions caused by road-building, and the likelihood that more roads can only lead to more cars and traffic are powerful factors bearing down on a 1950s-style construction program.The goal of smart-highway technology is to make traffic systems work at optimum efficiency by treating the road and the vehicles traveling on them as an integral transportation system. Proponents of the advanced technology say electronic detection systems, closed-circuit television, radio communication, ramp metering, variable message signing, and other smart-highway technology can now be used at a reasonable cost to improve communication between drivers and the people who monitor traffic.Pathfinder, a Santa Monica, California-based smart-highway project in which a 14-mile stretch of the Santa Monica Freeway, making up what is called a "smart corridor", is being instrumented with buried loops in the pavement. Closed-circuit television cameras survey the flow of traffic, while communication linked to property equipped automobiles advise motorists of the least congested routes or detours.Not all traffic experts, however, look to smart-highway technology as the ultimate solution to traffic gridlock. Some say the high-tech approach is limited and can only offer temporary solutions to a serious problem."Electronics on the highway addresses just one aspect of the problem: how to regulate traffic more efficiently," explains Michael Renner, senior researcher at the world-watch Institute. "It doesn’t deal with the central problem of too many cars for roads that can’ t be built fast enough. It sends people the wrong message. They start thinking "Yes, there used to be a traffic congestion problem, but that’s been solved now because we have, advanced high-tech system in place." Larson agrees and adds, "Smart highways is just one of the tools that we use to deal with our traffic problems. It ’snot the solution itself, just pan of the package. There are different strategies."Other traffic problem-solving options being studied and experimented with include car pooling, rapid mass-transit systems, staggered or flexible work hours, and road pricing, a system whereby motorists pay a certain amount for the time they use a highway.It seems that we need a new, major thrust to deal with the traffic problems of the next 20 years. There has to be a big change. According to the passage, the smart-highway technology is aimed to ()
A. develop sophisticated facilities on the interstate highways
B. provide passenger vehicle with a variety of services
C. optimize the highway capabilities
D. improve communication between driver and the traffic monitors
Traffic statistics paint a gloomy picture. To help solve their traffic woes, some rapidly growing U.S. cities have simply built more roads. But traffic experts say building more roads is a quick-fix solution that will not alleviated the traffic problem in the long nm. Soaring land costs, increasing concern over social and environmental disruptions caused by road-building, and the likelihood that more roads can only lead to more cars and traffic are powerful factors bearing down on a 1950s-style construction program.The goal of smart-highway technology is to make traffic systems work at optimum efficiency by treating the road and the vehicles traveling on them as an integral transportation system. Proponents of the advanced technology say electronic detection systems, closed-circuit television, radio communication, ramp metering, variable message signing, and other smart-highway technology can now be used at a reasonable cost to improve communication between drivers and the people who monitor traffic.Pathfinder, a Santa Monica, California-based smart-highway project in which a 14-mile stretch of the Santa Monica Freeway, making up what is called a "smart corridor", is being instrumented with buried loops in the pavement. Closed-circuit television cameras survey the flow of traffic, while communication linked to property equipped automobiles advise motorists of the least congested routes or detours.Not all traffic experts, however, look to smart-highway technology as the ultimate solution to traffic gridlock. Some say the high-tech approach is limited and can only offer temporary solutions to a serious problem."Electronics on the highway addresses just one aspect of the problem: how to regulate traffic more efficiently," explains Michael Renner, senior researcher at the world-watch Institute. "It doesn’t deal with the central problem of too many cars for roads that can’ t be built fast enough. It sends people the wrong message. They start thinking "Yes, there used to be a traffic congestion problem, but that’s been solved now because we have, advanced high-tech system in place." Larson agrees and adds, "Smart highways is just one of the tools that we use to deal with our traffic problems. It ’snot the solution itself, just pan of the package. There are different strategies."Other traffic problem-solving options being studied and experimented with include car pooling, rapid mass-transit systems, staggered or flexible work hours, and road pricing, a system whereby motorists pay a certain amount for the time they use a highway.It seems that we need a new, major thrust to deal with the traffic problems of the next 20 years. There has to be a big change. The compound word "quick-fix" in Paragraph 1, sentence 3 is closest in meaning to ()
A. an optional solution
B. an expedient solution
C. a ready solution
D. an efficient solution
某医师用A药治疗9例病人,治愈7人;用B药治疗10例病人,治愈1人,比较两药疗效时,可选用的最适当方法是
A. χ2检验
B. 校正χ2检验
C. t检验
D. u检验
E. 直接计算概率法