Taking a Nap During the Day Medical experts say most Americans do not get (51) sleep. They say more Americans need to rest for a short period in the middle of the day. They are advising people to sleep lightly before (52) with other activities. One study earlier this year found that persons who sleep for a few minutes during the day were less (53) to die of disease. The study followed more than 2,300 Greek adults (54) about six years. Adult who rested for half an hour (55) three times a week had a 37 percent lower risk of dying from heart disease than those who did not nap. Study organizers said the strongest evidence was in working men. They said naps might improve (56) by mitigating tension caused by work. Some European and Latin American businesses have supported the (57) of napping for many years. They urge people to (58) work, go home and have a nap before returning. In the United States, some companies let workers rest briefly in their offices. They believe this reduces in their offices. They believe this reduces (59) and accidents, and (60) increases the amount of work a person can do. Sleep experts say it is likely that people make more mistakes at work than at other times. They say people should not carry out important duties when they feel (61) . And they say the best thing to do is to take a nap. About twenty minutes of rest is (62) you need. Experts say this provides extra energy and can increase your effectiveness (63) the end of the day. But experts warn that a nap (64) last no more than twenty to thirty minutes. A longer nap will put the body into deep sleep and waking up will be (65) .
A. helpful
B. difficult
C. easy
D. happy
Irish Dolphins may Have a Unique Dialect Irish scientists monitoring dolphins living in a river estuary in the southwest of the country believe they may have developed a unique dialect to communicate with each other. The Shannon Dolphin and Wildlife Foundation (SDWF) has been studying a group of up to 120 bottle-nose dolphins in the River Shannon using vocalizations collected on a computer in a cow shed near the River Shannon. As part of a research project, student Ronan Hickey digitized and analyzed a total of 1,882 whistles from the Irish dolphins and those from the Welsh dolphins on a computer and separated them into six fundamental whistle types and 32 different categories. Of the categories, he found most were used by both sets of dolphins but eight were only heard from the Irish dolphins. "We are building up a catalogue of the different whistle types they use and trying to associate them with behavior like foraging, resting, socializing and the communications of groups with calves," project leader Simon Berrow said. "Essentially we are building up what is like a dictionary of words they use or sounds they make." Berrow, a marine biologist, said the dolphins’ clicks are used to find their way around and locate prey. The whistles are communications. "They do a whole range of other sounds like barks, groans and a kind of gunshot," he said. "The gunshot is an intense pulse of sound. Sperm whales use it to stun their prey." "When I first heard it I was surprised as I thought sperm whales were the only species who used it. We can speculate the dolphins are using it for the same reason as the sperm whales," Berrow said. References in local legend indicate there have been dolphins in the Shannon estuary for generations and they may even have been resident there as far back as the 6th century. They are regularly seen by passengers on the Shannon ferry and an estimated 25,000 tourists every year take special sightseeing tours on local boats to visit them. Ronan Hickey analyzed almost 2000 different dialects of the bottle-nose dolphins.
A. Right
B. Wrong
C. Not mentioned
CT Scans and Lung Cancer Small or slow-growing nodules (小结节) discovered on a lung scan are unlikely to develop into tumors over the next two years, researchers reported on Wednesday. The findings reported in the New England Journal of Medicine, could help doctors decide when to do more aggressive testing for lung cancer. They could also help patients avoid unnecessarily aggressive and potentially harmful testing when lesions (损伤) found. Lung cancer, the biggest cancer killer in the United States and globally, is often not diagnosed until it has spread. It kills 159,000 people a year in the United States alone. The work is part of a larger effort to develop guidelines to help doctors decide what to do when such growths, often discovered by accident, appear in a scan. High-tech X-rays called CT scans can detect tumors-but they see all sorts of other blobs (模糊的一团) that are not tumors, and often the only way to tell the difference is to take a biopsy (活检), a dangerous procedure. At the moment, routine lung cancer screening is considered impractical because of its high cost and because too many healthy people are called back for further testing. Good guideline could help make lung cancer screening practical, Dr. Rob van Kiaveren of the Erasmus Medical Center in Rotterdam, the Netherlands, who led the new study, said in a telephone interview. The team looked at 7, 557 people at high risk for lung cancer because they were current and former smokers. All received multidetector (多层螺旋) CT scans that measured the size of any suspicious-looking modules. Volunteers who had nodules over 9.7 mm in width, or had growth of 4.6 mm that grew fast enough to more than double in volume every 400 days, were sent for further testing. Of the 196 people who fell into that category, 70 were found to have lung cancer, 10 additional cases were found years later. But of the 7, 361 who tested negative during screening only 20 lung cancer cases later developed. In a second round of screening done one year after the first, 1.8 percent were sent to the doctor because they had a nodule that was large or fast-growing. More than half turned out to have lung cancer. The result means that if the screening test says you don’t have lung cancer, you probably don’t, the researcher said. "The chances of finding lung cancer one and two years after a negative first-round test were 1 in 1,000 and 3 in 1,000 respectively, "they concluded. Which is probably NOT true of lung cancer
A. Smokers are usually considered to be at high risk for it.
B. It is the leading cause of cancer deaths around the world.
C. 159,000 new cases of it are diagnosed in the US each year.
D. It often goes unnoticed until it has sprea