单选题He saw writers and artists as being important to the state for they could ______ credibility on the regime.

单选题Doctors can easily tell when someone is having a heart attack, but one thing they can't do is to predict an attack before it happens. Even patients who come in for stress tests and get a clean bill of health often end up back in the hospital with a heart attack just days later. But researchers say that may soon change, thanks to a study that used a blood test to detect certain cells that are sloughed off from weakened blood vessel walls. The cells are called circulating endothelial ceils (CECs) and they herald the first stages of a heart attack, according to Dr. Eric Topol, chief academic officer for Scripps Health and lead author of the study published in the journal Science Translational Medicine. Heart experts currently believe that heart attacks start days before a clot actually forms and blocks the flow of blood to the heart, says Topol. The first stages of a heart attack involve a weakening or erosion of the blood vessel walls, which then attracts inflammatory cells that damage the endothelial cells lining the inside of the blood vessels. Eventually, under the immense inflammatory pressure, these cells undergo mutations and start to clump together before sloughing off to float around in the blood. In the study, involving 50 patients who had a heart attack and 44 healthy controls, the heart attack patients had more than four times the concentration of CECs in their blood than the controls. The CECs in the heart patients also looked different from those in the healthy people, often appearing misshapen and large, with multiple nuclei. Researchers first connected CECs to impending heart attacks back in 1999, but Topol's work takes that early investigation further, with a more sophisticated way of identifying CECs in the blood. The current research is also the most indepth study to date of the structural changes that distinguish these cells. "For the first time, we can isolate these cells through techniques that were not available in 1999," says Topol. "They are like a window into the process that underlies an imminent heart attack." The researchers were able to draw on work from the cancer field, where efforts to identify tumor cells that break off from growths and enter the bloodstream are helping to diagnose cancers earlier. Using specific proteins or cell markers that appear exclusively on the surface of blood vessel cells, Topol and his colleagues came up with a molecular profile for CECs that he hopes will form the basis of a more user-friendly test in coming years. They are also in the process of doing extensive genetic tests on the cells in order to construct a dossier on its gene activity. Already, he says, they know that the cells are abnormal, and have more than one nucleus, compared to the single nucleus in normal cells. "These cells are sick," he says. "They are much multinucleated, and have undergone many somatic mutations and have altered cell structure." It's also becoming clear that the CECs start sloughing off the vessel walls a few days to a week or so before fatty plaques rupture and form blood clots, causing a heart attack. That means that testing for CECs can help doctors predict who is on the verge of having an event. This could be especially helpful for the many patients who come into emergency rooms every day, complaining of vague chest-tightening or tingling sensations, but show no signs of the elevated heart enzymes that would indicate a heart attack. These people are often sent home, only to come back several days later with a heart attack—and by that time it's too late, the heart muscle may already be damaged. "It's one of the most common misdiagnoses in American medicine," says Topol, "of the missed signs of heart attack." If the test is validated, it might immediately be used to triage such patients, helping to predict who will have a heart attack in coming days and who is likely suffering from some other ailment, such as severe indigestion or heartburn. But ultimately, Topol hopes to see the technology embedded into a more permanent surveillance device that could keep track of CEC concentrations on a continuous basis. "In the long term, now that we have the molecular signature of the CECs, we could put it in a nanosensor that is embedded into a tiny vein in high risk people who are most vulnerable to having a heart attack, and have that sensor talk to their cell phone, so they get an alert that they might have a heart attack in a few days." That's still a long way away, but the results suggest that the more immediate benefits of checking for CECs might help thousands of people predict, and possibly avoid, their next heart attack.

单选题The BBC dictionary differs from Oxford and Longman in that ______.

单选题Except for {{U}}coarse{{/U}} earthen-wares, which can be made from clay as it is found in the earth, pottery is made from special clays plus other materials mixed to achieve the desired results. A. conventional B. unique C. genuine D. crude

单选题The passage is mainly to tell ______.

单选题Heat exhaustion is a condition caused by ______to sunlight or another heat source which often results in dehydration and salt depletion. A.a reaction to B.overexposure C.a limitation of D.an absence of

单选题This report examines the social and economic development policies enacted by three countries to ______ a resurgence of terrorism within their jurisdictions.

单选题Critics of early schooling cite research that questions whether 4-year-old children are ready to take on formal learning. Educators find that (21) toddlers are more likely to succeed during. their school careers. (22) their younger counterparts are more likely to (23) . Kindergarten children who turn five during the (24) half of the year seem to be at a disadvantage when it (25) physical, emotional, social, and intellectual development. Additionally, children who are nearly six when they enter kindergarten (26) to receive better grades and score higher on achievement (27) throughout their schooling experience (28) do those who begin kindergarten having just turned five. Being bright and verbally skillful and being ready for school do not seem to be the (29) thing. It is easy to confuse the superficial poise and sophistication of many of today's children (30) inner maturity. Indeed, evidence suggests that early schooling boomerangs: Youngsters (31) parents push them to attain academic success in preschool are less creative, have (32) anxiety about tests, and, by the end of kindergarten, fall to maintain their initial academic advantage (33) their less-pressured peers. Many psychologists and educators remain skeptical of approaches that place 4-year-olds in a formal educational setting. They question (34) environmental enrichment can significantly alter the built-in developmental timetable of a child reared in a non-disadvantaged home. They do not deny, however, the (35) of day-care centers and nursery schools that provide a homelike environment and allow children (36) freedom to play, develop at their own (37) , and evolve their social skills. But they point out that many of the things children once did in first grade are now (38) of them in kindergarten, and they worry lest more and more will now be asked of 4- year-olds. These psychologists and educators believe we are driving young children too (39) and thereby depriving them of their (40) .

单选题[此试题无题干]

单选题The law of private international tribunals with respect to conflicts of interest of arbitrators is quite extensive, albeit by no means uniform. It relates both to what will disqualify an arbitrator and to what the arbitrator must disclose during the selection process. Most national legal systems have statutory roles as to the types of interests, relationships, and experiences that disqualify an arbitrator. Not infrequently, the disqualifying factors are identical for arbitrators and judges, although they may treat domestic and international arbitration somewhat differently, and may indeed supplement the international roles with additional features. A closer look reveals that courts and arbitration agencies tend to apply the regulations relatively lightly, recognizing that arbitrators move in the highly interconnected world of affairs, and do not stand aloof from commerce as judges do. Accordingly, acquaintanceship with the parties and their counsel does not suffice to disqualify, whereas actual business or legal connections will. Inasmuch as judges do not seek more work, although arbitrators generally do, suspicions arise that an arbitrator's favor may incline to the party or counsel who has in the past and may again in the future provide employment. The uncertainty in the field is at its most troubling when arbitrators are party-appointed. Some argue that such arbitrators should fulfill the same functions and satisfy the same qualifications as third-party arbitrators, others dispute any real claim to objectivity. The latter view has had considerable currency, particularly in the United States, where courts and drafters of state laws regard such advocates as pawns of the appointers. Imposing standards of neutrality, and disinterestedness on them would be futile. It follows from this dichotomy between party-appointed and non-party-appointed arbitrators that opinion on the question of their nationality is also split. A party needs to be expected to choose a fellow national. This question of nationality is acute when one party to the arbitration is a governmental agency and one or more of the arbitrators are likewise nationals; a foreign enterprise contract calling for such arbitration may be foolhardy. The slate is largely blank with respect to roles for the conduct of arbitrators outside the field of conflict of interests. Considering only the matter of exparte communications, American case law is astonishing lax, refusing to set aside awards where such communication obtained between an arbitrator and a party without the presence of the other party, thereby violating evidentiary rules requiring the attendance of both parties. The differences in views on this topic indicate how useful a set of guidelines might be.

单选题It was ______ by the railway board that the cost of rail fares would be increased by ten percent.

单选题Attempts to persuade her stay after she felt insulted were ______.

单选题He was unable to endure the torture of the enemy and surrendered. He ______ his comrades.

单选题The ex-president had been ______ in the country to refresh his mind before he passed away.

单选题We need more men of culture and enlightment because we have too many ______ among US. A. students B. laymen C. pragmatists D. philosophers

单选题The country's failure to abide by the Kyoto Protocol was______in all newspapers.

单选题Now that he has retired, he lives partly on his pension and partly on the ______ on his bank-savings account.