首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
Radiation occurs from three natural sources: radioactive material in the environment, such as in soil, rock, or building materia
Radiation occurs from three natural sources: radioactive material in the environment, such as in soil, rock, or building materia
admin
2010-09-06
44
问题
Radiation occurs from three natural sources: radioactive material in the environment, such as in soil, rock, or building materials; cosmic rays; and substances in the human body, such as radioactive potassium in bone and radioactive carbon in tissues. These natural sources account for an exposure of about 100 millirems a year for the average American.
The largest single source of man-made radiation in medical x-rays, yet most scientists agree that hazards from this source are not as great as those from weapons test fallout, since strontium-90 and carbon-14 become incorporated into the body, hence delivering radiation for an entire lifetime. (46)
The issue is, however, by no means uncontroversial; indeed, the last two decades have witnessed intensified examination and dispute about the effects of low-level radiation.
A survey conducted in Britain confirmed that an abnormally high percentage of patients suffering from arthritis of the spine who had been treated with x-rays contracted cancer. Another study revealed a high incidence of childhood cancer in cases where the mother had been given x-rays. (47)
These studies have pointed to the need to re-examine the assumption that exposure to low linear energy transfer presented only a minor risk.
Recently, examination of the death certificates of former employees of a West Coast plant which produces plutonium for nuclear weapons revealed markedly higher rates for cancers of the pancreas, lung, bone marrow and lymph systems than would have been expected in a normal population.
(48)
While the National Academy of Sciences committee attributes these differences to chemical or other environmental causes, rather than radiation, other scientists maintain that any radiation exposure, no matter how small, leads to an increase in cancer risk.
(49)
It is believed by some that a dose of one rem, if sustained over many generations, would lead to an increase of one percent in the number of 1,000 disorders per million births.
In the meantime, regulatory efforts have been disorganized, fragmented, and inconsistent, characterized by internecine strife and bureaucratic delays. A Senate report concluded that coordination of regulation among involved departments and agencies was not possible because of jurisdictional disputes and confusion. (50)
One Federal agency has been unsuccessful in its efforts to obtain sufficient funding and manpower for the enforcement of existing radiation laws, and the chairperson of a panel especially created to develop a coordinated Federal program has resigned.
选项
答案
国家科学委员会把这些差异归因于化学的或其他环境的因素,而不是辐射。但是其他科学家却坚持认为接触任何程度的辐射,不管有多小,结果都会增加患癌症的危险。
解析
转载请注明原文地址:https://jikaoti.com/ti/TT7RFFFM
0
考研英语一
相关试题推荐
Thecostsassociatedwithnaturaldisastersareincreasingrapidly.Asaresult,officialsingovernmentandindustryhavefocus
Byeducation,Imeantheinfluenceoftheenvironmentupontheindividualtoproduceapermanentchangeinthehabitsofbehavio
Writeanessaybasedonthefollowingtable.Inyourwriting,youshould1)describethetableand2)stateyouropinionsdrawn
Writeanessaybasedonthefollowingchart.Inyourwriting,youshould1)interpretthechart,and2)giveyourcomments.You
Writeanessaybasedonthefollowingtable.Inyourwriting,youshould1)describethetable,and2)giveyourcomments.You
Threemakesatrend.TheWashingtonPostCo.FridayannouncedthatitwouldlooktosellitsheadquartersbuildingindowntownW
(Havingbeen)robbed(off)economicimportance,thosestatesare(not)likelytocountfor(verymuch)ininternationalpolitica
Theauthorbelievesthat______.Thepassageismainlyabout______.
随机试题
个人品德是指个人依据一定的道德原则规范行动时所表现出来的稳固的倾向和特征。关于个人品德的形成,有不同的观点。下列观点中正确揭示了个人品德形成过程和规律的是()
Longafterthe1998WorldCupwaswon,disappointedfanswerestillcursingthedisputedrefereeing(裁判)decisionsthatdeniedvic
某患者腰痛伴右下肢放射痛反复发作,与劳累有关,咳嗽、用力排便时可加重疼痛。查体:右直腿抬高试验40°阳性,加强试验阳性;X线片示L4—L5椎间隙变窄。可完金排除的诊断是()
男,35岁。因刷牙时牙龈出血就诊。检查:牙龈颜色发红,龈袋深2mm,舌侧有龈下牙石,探诊后出血。该患者的CPI指数计分为()
关于民事诉讼的裁定,下列哪一选项是正确的?
FIDIC合同条件中约定,因承包商的责任延误竣工时,损害赔偿金为每天1万元,该合同工程的总金额为300万元,而承包商该竣工工程的合同价为15万元,延期竣工天数为30天,合同中还约定最高赔偿限额为20万元,则在工程结算时可折减的误期损害赔偿金为( )万元。
如果把进度偏差与投资偏差联系起来,则进度偏差可表示为()与已完工程计划投资的差异。
下列属于项目贷款的用途的有()。
为了接受社会监督,公安部于1999年5月10日发出了《关于在全国公安机关普遍实行警务公开制度的通知》,决定在全国公安机关普遍实行警务公开制度。()
可以由全国人大罢免的国家领导人员的有()。
最新回复
(
0
)