题目:
SS4型电力机车段修技术规程要求,TCK7F型电空接触器主触头对地绝缘电阻值应不低于()。
A、3MQ
B、5MQ
C、8MQ
D、10MQ
答案:
参考答案:B
SS4型电力机车段修技术规程要求,TCK7F型电空接触器主触头对地绝缘电阻值应不低于()。
A、3MQ
B、5MQ
C、8MQ
D、10MQ
参考答案:B
蛇蜕的别名是()
A.仙灵脾
B.龙衣
C.通脱木
D.接骨草
E.夜交藤
患儿,男,3岁。平日活动后心悸、气促,常患肺炎,发育落后,胸部听诊可闻及杂音,有末梢毛细血管搏动、水冲动。临床诊断为动脉导管未闭。
对患儿做健康指导时错误的是()。
A.向患儿及家长讲解本病的病因
B.指导家长合理安排患儿的食宿
C.停止各种预防接种
D.介绍本病的治疗进展
E.指导如何观察患儿活动过量的表现
有观察家指出,自从美国发动反恐战争以及朝核危机爆发以来,中美之间过去最具争议的问题,如 * * 和西藏问题等,在双边关系中已经降到次要位置。
根据我国消费者权益保护法的规定,消费者协会履行的职能之一是()
A、参与生产企业的年度生产计划的制定
B、受理经营者的投诉,并对投诉事项进行调查、调解
C、参与销售企业市场开拓计划的制定
D、对损害消费者合法权益的行为,通过大众传播媒介予以揭露、批评
Researchers investigating brain size and mental ability say their work offers evidence that education protects the mind from the brain’s physical deterioration.
(46) is known that the brain shrinks as the body ages, but the effects on mental ability are different from person to person. Interestingly, in a study of elderly men and women, those who had more education actually had more brain shrinkage.
"That may seem like bad news," said study author Dr. Edward Coffey, a professor of psychiatry and of neurology at Henry Ford Health System in Detroit.
(47) However, he explained, the finding suggests that education allows people to withstand more brain tissue loss before their mental functioning begins to break down..
The study, published in the July issue of Neurology, is the first to provide biological evidence to support a concept called the "reserve" hypothesis, according to the researchers. In recent years, investigators have developed the idea that people who are more educated have greater cognitive reserves to draw upon as the brain ages; in essence, they have more brain tissue to spare.
(48) Examining brain scans of 320 healthy men and women aged 66 to 90, researchers found that for each year of education the subjects had, there was greater shrinkage of the outer layer of the brain known as the cortex. Yet on tests of cognition and memory, all participants scored in the range indicating normal.
"Everyone has some degree of brain shrinkage," Coffey said. "People lose (on average) 2.5 percent per decade starting in adulthood."
There is, however, a "remarkable range" of shrinkage among people who show no signs of mental decline, Coffey noted. Overall health, he said, accounts for some differences in brain size. Alcohol or drug use, as well as medical conditions such as diabetes and high blood pressure, contribute to brain tissue loss throughout adulthood.
In the absence of such medical conditions, Coffey said, education level helps explain the range of brain shrinkage exhibited among the mentally-fit elderly. The more-educated can withstand greater loss.
(49) Coffey and colleagues gauged shrinkage of the cortex by measuring the cerebrospinal fluid surrounding the brain. The greater the amount of fluid, the greater the cortical shrinkage.
Controlling for the health factors that contribute to brain injury, the researchers found that education was related to the severity of brain shrinkage. For each year of education from first grade on, subjects had an average of 1.77 milliliters more cerebrospinal fluid around the brain. Just how education might affect brain cells is unknown.
(50) In their report, the researchers speculated that in people with more education, certain brain structures deeper than the cortex may stay intact to compensate for cortical shrinkage.
(46) is known that the brain shrinks as the body ages, but the effects on mental ability are different from person to person.