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1、第 1 页 共 14 页 2015 年职称英语考试 理工 A真题 2015 年职称英语考试 理工 A真题 Lackof Oxygen Delayed the Rise of Animals on Earth Scientistshave long speculated as to why animal species didnt flourish sooner, oncesufficient oxygen covered the Earths surface. Animals began to prosper at theend of the Proterozoic period, about
2、 800 million years ago but what about thebillion-year stretch before that, when most researchers think there also wasplenty of oxygen? Well,it seems the air wasnt so great then, after all. Ina study published Oct. 31 in Science, Yale researcher Noah Planavsky and hiscolleagues found that oxygen leve
3、ls during the “boring billion” period wereonly 0.1% of what they are today. In other words, Earths atmosphere couldnthave supported a diversity of creatures, no matter what genetic advancementswere poised to occur. “There is no questionthat genetic and ecological innovation must ultimately be behind
4、 the rise ofanimals, but it is equally unavoidable that animals need a certain level ofoxygen,” said Planavsky, co-lead author of the researchalongwithChristopherReinhardoftheGeorgiaInstituteof Technology. “Were providing the firstevidence that oxygen levels were low 第 2 页 共 14 页 enough during this
5、period to potentiallyprevent the rise of animals.” Thescientists found their evidence by analyzing chromium (Cr) isotopes in ancientsediments from China, Australia, Canada, and the United States. Chromium isfound in the Earths continental crust, and chromium oxidation is directlylinked to the presen
6、ce of free oxygen in the atmosphere. Specifically,the team studied samples deposited in shallow, iron-rich ocean areas, near theshore. They compared their data with other samples taken from younger localesknown to have higher levels of oxygen. Oxygensrole in controlling the first appearance of anima
7、ls has long vexed scientists.“We were missing the right approach until now,” Planavsky said. “Chromium gaveus the proxy.” Previous estimates put the oxygen level at 40% of todaysconditions during pre-animal times, leaving open the possibility that oxygenwas already plentiful enough to support animal
8、 life. Inthe new study, the researchers acknowledged that oxygen levels were “highlydynamic” in the early atmosphere, with the potential for occasional spikes.However, they said, “It seems clear that there is a first-order difference inthe nature of Earth surface Cr cycling” before and after the ris
9、e of animals. “If we are right, ourresults will really change how people view the origins of animals and othercomplex life, and their relationships to the co-evolving environment,”saidco-authorTimLyonsoftheUniversityof California-Riverside. “This could be agame changer.” 第 3 页 共 14 页 Fundingsources
10、for the research included the NASA Exobiology Program andtheNationalScienceFoundationsEarth-LifeTransitionsprogram, awarded to Planavsky,Reinhard, and Lyons. Theother members of the research team included Xiangli Wang, a postdoctoral fellowat Yale; Thomas Johnson, of the University of Illinois; Dani
11、elle Thomson, ofCarleton University; Peter McGoldrick, of the University of Tasmania; andWoodward Fischer, of the California Institute of Technology. 16.The study discovered the rise of animals occurred earlier than the Proterozoicperiod. A.Right B. Wrong C. Not mentioned 17.Many researchers believe
12、 the oxygen level was high during pre-animal times. A. Right B. Wrong C.Not mentioned 18. The teamwas funded by several research institutes. A.Right B. Wrong C. Not mentioned 19. Geneticadvancements triggered the rise of animals. A.Right B. Wrong C. Not mentioned 20. Thesamples studied in the resear
13、ch were collected in ocean areas. A. Right B. Wrong C.Not mentioned 21. Thestudy revealed that chromium found in Earths continental crust 第 4 页 共 14 页 remained stablebefore and after the rise of animals. A.Right B. Wrong C. Not mentioned 22. TimLyons liked to play computer games in his spare time. A
14、.Right B. Wrong C. Not mentioned 据网友提供信息， 2015 年职称英语考试理工 A 概括大意与完成句子真题及 答案，广大考生可以参考本帖，对照答案。 FirstImage-recognition Software 1.Dartmouth researchers and their colleagues have created an artificial 1 ,software that uses photos to locate documents on the Internet with far gre jthan ever before. 2.The n
15、ew system, which was tested on photos and is now being applied to , Ishows for the first time that a machine learning algorithm ( 运 算 法 则 )or ,ma9e I recognition and retrieval is accurate and efficient enough toimprove large seaie , document searches online. The system uses pixel (像 素 )data in image
16、s and potentia y video rather than just text to locatedocuments. It learns to recognize the pixels associated with a search phrase bystudying the results from text-based image search engines. The knowledgegleaned ( 收 集 ) from those results can then beapplied to other photos without tags or captions making for more accuratedocument search results. 3.“Over the last 30 years,“ says Associate Professor Lorenzo Torresani,a 第 5 页 共 14 页 co-author of the study, “the Web has evolved
