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
54
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
然而,这个问题绝对是有争议的。事实上,最近20年中人们对低幅度辐射影响有了进一步的检测和争论。
解析
转载请注明原文地址:https://kaotiyun.com/show/boZ4777K
0
考研英语一
相关试题推荐
Innovationiskeytobusinesssurvival,andcompaniesputsubstantialresourcesintoinspiringemployeestodevelopnewideas.T
Thecostsassociatedwithnaturaldisastersareincreasingrapidly.Asaresult,officialsingovernmentandindustryhavefocus
Nameshavegainedincreasingimportanceinthecompetitiveworldofhighereducation.Ascollegesstriveformarketshare,they
Writeanessaybasedonthefollowingtable.Inyourwriting,youshould1)describethetableand2)stateyouropinionsdrawn
BankruptcyratesintheU.S.havebeengrowingformorethantwodecadesdespitegenerallyrisinglevelsofpersonalincome.The
Writeanessaybasedonthefollowingchart.Inyourwriting,youshould1)interpretthechart,and2)giveyourcomments.You
Howlongyoulivehasmuchtodowithyourenvironmentandlifestylesuchasnotsmoking,eatingahealthydietandremainingso
Writeanessaybasedonthefollowingchart.Inyourwriting,youshould1)interpretthechart,and2)giveyourcomments.You
Writeanessaybasedonthefollowingtable.Inyourwriting,youshould1)describethetable,and2)giveyourcomments.You
随机试题
()企业的成功使得人们开始重视全面质量管理的重要性。
下列菜肴必须经过原料分割或剔骨整理的工序后才能制成的菜肴是________。
重症肺炎和轻型肺炎的区别是
一家饮料公司投资建了一座饭店,同时还拥有电器制造、汽车运输、食品加工等企业。该企业采取的是( )。
对某种特定商品有兴趣的消费者的集合是()。
某机场工程实行公开竞争性招标,招标公告中要求投标者应是具有一级资质等级的施工企业。在开标会上,共有12家参与投标的施工企业或联合体有关人员参加,此外还有市招标办公室、市公证处法律顾问以及业主方的招标委员会全体成员参加。开标前,公证处提出要对各投标单位的资质
根据马科维茨提出的理论,使投资者最满意的证券组合是()。
承办期限制度要求人们照章办事,不准人们的行为偏离规定的要求,以提升企业的()
眼手协调动作发生于()。
已知设D为由x=0、y=0及x+y=t所围成的区域,求F(t)=f(x,Y)dxdy.
最新回复
(
0
)