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风险报酬就是投资者因冒风险进行投资而实际获得的超过资金时间价值的那部分额外报酬。()
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At the fall 2001 Social Science History Association convention in Chicago, the Crime and Justice network sponsored a forum on the history of gun ownership, gun use, and gun violence in the United States. Our purpose was to consider how social science historians might contribute to the public debate over gun control and gun rights. To date, we have had little impact on that debate. It has been dominated by mainstream social scientists and historians, especially scholars such as Gary Kleck, John Lott, and Michael Bellesiles, whose work, despite profound flaws, is politically congenial to either opponents or proponents of gun control. Kleck and Mark Gertz, for instance, argue on the basis of their widely cited survey that gun owners prevent numerous crimes each year in the United States by using firearms to defend themselves and their property. If their survey respondents are to be believed, American gun owners shot 100, 000 criminals in 1994 in self-defense--a preposterous number. Lott claims on the basis of his statistical analysis of recent crime rates that laws allowing private individuals to carry concealed firearms deter murders, rapes, and robberies, because criminals are afraid to attack potentially armed victims. However, he biases his results by confining his analysis to the year between 1977 and 1992, when violent crime rates had peaked and varied little from year to year. He reports only regression models that support his thesis and neglects to mention that each of those models find a positive relationship between violent crime and real income, and an inverse relationship between violent crime and unemployment.
Contrary to Kleck and Lott, Bellesiles insists that guns and America's "gun culture" are responsible for America's high rates of murder. In Bellesiles's opinion, relatively few Americans owned guns before the 1850s or know how to use, maintain, or repair them. As a result, he says, guns contributed little to the homicide rate, especially among white, which was low everywhere, even in the South and on the frontier, where historians once assume guns and murder went hand in hand. According to Bellesiles, these patterns changed dramatically after the Mexican War and especially after the Civil War, when gun ownership became widespread and cultural changes encouraged the use of handguns to command respect and resolve personal and political disputes. The result was an unprecedented wave of gun-related homicides that never truly abated. To this day, the United States has the highest homicide rate of any industrial democracy. Bellesiles's low estimates of gun ownership in early America conflict, however, with those of every historian who has previously studied the subject and have thus far proven irreproducible.
Every homicide statistic he presents is either misleading or wrong.
Given the influence of KJeck, Lott, Beliesiles, and other partisan scholars on the debate over gun control and gun rights, we felt a need to pull together what social science historians have learned to date about the history of gun ownership and gun violence in America, and to consider what research methods and projects might increase our knowledge in the near future.
Which of the following statements is true about the public debate over gun control？
Visiting a National Park can be relaxing, inspiring and rejuvenating, but it can also be disturbing. As you drive into Rocky Mountain National Park, and you will see starving elk, damaged meadows and dying forests. Our parks are growing old because we have mistakenly protected them from natural processes, such as fire, predation, and insects. We believed that we were saving these remnants of wild America, but actually we have "protected" them to death. If we want to save our National Parks, the National Park Service must change its management priorities to-prevent over population of animals and to restore natural process in the forest in order to prevent their stagnation and "death" by old age. We must act soon: our parks are dying of old age because we have altered the forces in nature that keep them young and strong.
By tracing the history of our National Parks, we can understand the problem and see why we need active management. In the early part of the 20th century, settlers exploited wildlife heavily, resulting in near-extinction of many species. Therefore, several National Parks were established by Congress primarily to save endangered animals. However, stricter wildlife protection laws and improved wildlife management techniques resulted in greater populations of animals overcrowding in areas of high concentration, such as the Yellowstone elk herds. Complicating the problem, the National Park Service in the early part of the 20th century adopted a policy of aggressive predator elimination, thus reducing natural wildlife population control. Subsequently, elk and deer populations exploded in many National Parks, resulting in severe damage to native vegetation. Vigorous forest fire and insect suppression in the National Parks throughout the 20th century further altered the natural environment by allowing forests to over-mature, without natural thinning processes. Park managers thought that they were protecting the land, but actually they were removing important controls from the forest ecosystems.
Clearly, we must act immediately if we want to pass down to our children and grandchildren the green legacy of our National Parks; we must step in and restore the natural processes which we have altered through our well-intentioned, but misguided, policies in the past.
According to the article, strict wildlife protection laws and improved wildlife management techniques ______.
A．ownedB．owedC．rentedD．sold
食滞胃脘之泄泻特点为E．
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