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
60
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
Inthelate1960’s,manypeopleinNorthAmericaturnedtheirattentiontoenvironmentalproblems,andnewsteel-and-glassskysc
Imaginefishermenwalkingdowntotheseashore,readytocarryouttheirearlymorningroutineofpreparingtheirboatsandnet.
Itisoftenobservedthattheagedspendmuchtimethinkingandtalkingabouttheirpastlives,【C1】______aboutthefuture.Thes
Lowlevelsofliteracyandnumeracyhaveadamagingimpactonalmosteveryaspectofadults,accordingtoasurveypublishedyes
Writeanessayof160~200wordsbasedonthefollowingdrawings.Inyouressay,youshould:1)describethepicturesbriefly,
Writealettertoyourcousin,whoisgoingtotaketheCollegeEntranceExaminationandfeelsstressed,givinghersomesuggest
How’sthisforacynicalviewofscience?(46)"Anewscientifictruthdoesnottriumphbyconvincingitsopponentsandmakingth
Writeanessayof160—200wordsbasedonthefollowingdrawing.Inyouressay,youshould1)describethedrawingbriefly,2)
FromTheTippingPointtoNudge,theriseofpop-socialsciencehasbeenanoticeablefeatureofthepastdecadeinpublishing.
Almosteverydayweseesomethinginthepapersaboutthelatestexcitingdevelopmentsinthespacerace.Photographsareregula
随机试题
有如下程序:#includeusingnamespacestd;classBase{public:Base(intx=0){cout
患者,男,29岁。发现血压升高2~3年,血压最高180/100mmHg,尿常规检查示尿蛋白(++),血生化检查示血肌酐642μmol/1,最可能的诊断是
一日,甲带邻家男孩乙到公园玩,甲想“吓唬”乙一下,就提着他的双脚将其倒悬于一座桥的栏杆外,乙边喊“饶命”边挣扎,甲手一滑,乙掉入河中,甲急忙去救,乙已溺水而亡,甲对乙的死亡结果在主观上所持的心理态度是:()
根据《期货公司管理业务试点办法》,下列人员可以作为期货公司资产管理业务客户的是()。
某企业月初结存材料的计划成本为250万元,材料成本差异为超支45万元;当月入库材料的计划成本为550万元,材料成本差异为节约85万元;当月生产车间领用材料的计划成本为600万元。当月生产车间领用材料的实际成本为()万元。
小亮3岁半,在幼儿园里,他很喜欢搭积木,每当有人问谁搭得漂亮时,他总是说自己搭得好,而事实并非如此。问题:请结合幼儿自我评价的有关原理加以分析。
根据《中华人民共和国宪法》的规定,处理全国人大常委会的重要日常工作的机关是()。
一古代算数例题:“今有大夫、不更、簪袅、上造、公士凡五人。共猎得五鹿,欲以爵次分之,问各得几何?”书中记载正确的答案是:他们依次分别得到5/3、4/3、1、2/3、1/3只鹿。请问,这道算数题反映了古代中国社会的哪项特色?
下列单位或个人可以成为纳税保证人的有()。
若f(x1,x2,x3)=2x12+x22+x32+2x1x2-tx2x3是正定二次型,则t的取值范围是________.
最新回复
(
0
)