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
2014-06-13
58
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 Freeport 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
有些人认为,一雷姆的剂量,如果在多代人中保留,那么每百万个出生儿中有一千个患有残疾的几率会增加1%。
解析
转载请注明原文地址:https://kaotiyun.com/show/f2K4777K
0
考研英语一
相关试题推荐
Imaginefishermenwalkingdowntotheseashore,readytocarryouttheirearlymorningroutineofpreparingtheirboatsandnet.
Itisoftenobservedthattheagedspendmuchtimethinkingandtalkingabouttheirpastlives,【C1】______aboutthefuture.Thes
Itisoftenobservedthattheagedspendmuchtimethinkingandtalkingabouttheirpastlives,【C1】______aboutthefuture.Thes
Lowlevelsofliteracyandnumeracyhaveadamagingimpactonalmosteveryaspectofadults,accordingtoasurveypublishedyes
Formorethanadecade,scientistshavebeentryingtodeterminewhetherclimatechangeislinkedtointensestorms,suchas200
Untilthelate1940swhentelevisionbeganfindingitswayintoAmericanhomes,companiesreliedmainlyonprintandradiotopr
Inherinternationalbestsellingdeath-of-mannersdeclarationTalktotheHand,authorLynneTrussarguesthatcommoncourtesies
Youcannotfinishyourtermpaperontimebecauseyoujoinedtheschool-organizedfieldpracticeprograminGuangzhouduringthe
Credibilityaboutmessagesishigh,becausetheyarereportedinindependentmedia.Anewspaperreviewofamoviehasmorebeli
Thepresidentappealstolaborandmanagementtoholddownwagesandprices,butsaysnotawordaboutanycontrolstobeimpose
随机试题
横轴位鼻咽腔的CT图象形态为:
房地产价格既有交换代价的价格,又有使用代价的租金,二者之间的关系可通过市场法确定。()
(2013年真题改编)如图6-16所示,水从直径相同的喷嘴喷出,打在平板上,流速分别为1m/s、2m/s,已知管道直径为50mm,水流速为4m/s,水对板的冲击力为()N。
甲公司发生下列有关交易性金融资产的业务:(1)2013年1月8日,甲公司购入丙公司发行的公司债券,该笔债券于2012年7月1日发行,面值为2500万元,票面利率为4%,债券利息按年支付。甲公司将其划分为交易性金融资产,支付价款为2600万元(其中包含已宣
下列对四川气候特征表述正确的是()。
黄某向刘某借款15万元,合同约定分三期偿还,第一期还款5万元,期限为2006年5月3日,第二期还款5万元,期限为2007年5月3日,第三期还款5万元,期限为2007年10月8日。时2009年9月5日,刘某要求黄某还款,黄某以第一期和第二期诉讼时效已过为由拒
()在我国的中间扩散型制度变迁方式中扮演着重要角色。
八国联军侵华后,侵略者曾扬言瓜分中国,然而最终未能如愿,八国联军统帅瓦德西认为,之所以无法瓜分中国,是因为“吾人对于中国群众,不能视为已成衰弱或已失德性之人,彼等在实际上,尚含有无限蓬勃生气,可于此次‘拳民运动’中见之……至于中国所有好战精神,尚未完全丧失
Manhaswoefullymisusedtheearth’snaturalresourcesdownthroughtheages.Thishasbeendonelargelythroughhisignoring
Thethievesfledwiththelocalpolicecloseontheir________.
最新回复
(
0
)