学生进行四则运算作业时,如果前面运算的作业题都是加法题,在计算加法题后再做乘法题时,易把“×”号看作是“+”号,而使计算出现错误,这种影响问题解决的因素叫( )。
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Lonely people, it seems, are at greater riskthan the gregarious of developing illnesses associated with chronicinflammation, such as heart disease and certain cancers. A paper published lastyear in the Public Library of Science, Medicine, shows the effect on mortalityof loneliness is comparable with thatof smoking and drinking after examining the results of 148 previous studies andcontrolled for factors such as age and pre-existing illness.
Steven Cole of the University ofCalifornia, Los Angeles, thinks he may know why this is so. He told theAmerican Association for the Advancement of Science meeting in Washington,D.C., about his work studying the expression of genes in lonely people. Dr.Cole harvested samples of white blood cells from both lonely and gregariouspeople. He then analysed the activity of their genes, as measured by theproduction of a substance called messenger RNA. This molecule carries instructions from the genes telling a cellwhich proteins to make. The level of messenger RNA from most genes was the samein both types of people. There were several dozen genes, however, that wereless active m the lonely, and several dozen others that were more active.Moreover, both the less active andthe more active gene types came from a small number of functional groups.
Broadly speaking, the genes less active in thelonely were those involved in staving off viral infections. Those that weremore active were involved in protecting against bacteria. Dr. Cole suspectsthis could help explain not only why the lonely are iller, but how, inevolutionary terms, this odd state of affairs has come about.
The crucial bit ofthe puzzle is that viruses have to be caught from another infected individual andthey are usually species-specific. Bacteria, in contrast, often just lurk inthe environment, and may thrive on manyhosts. The gregarious are therefore at greater risk than the lonely ofcatching viruses, and Dr. Cole thussuggests that past evolution has created a mechanism which causes white cellsto respond appropriately. Conversely, the lonely are better off ramping uptheir protection against bacterialinfection, which is a bigger relative risk to them.
What Dr. Cole seemsto have revealed, then, is a mechanism by which social environment reachesinside a person's body and tweaks its genome so that it responds appropriately.It is not that the lonely and the gregarious are genetically different fromeach other. Rather, their genes are regulated differently, according to howsociable an individual is. Dr. Cole thinks this regulation is part of a widermechanism that tunes individuals to the circumstances they find themselves in.
What message does Dr. Cole seem to convey by the mechanism?
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书法大赛的观众对5幅作品进行不记名投票。每张选票都可以选择5幅作品中的任意一幅或多幅,但只有在选择不超过2幅作品时才为有效票。5幅作品的得票数(不考虑是否有效)分别为总票数的69%、63%、44%、58%和56%。则本次投票的有效率最高可能为多少( )