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Some people can quite accurately time the end of their night’s sleep at will, without using an alarm clock, demonstrating that it is possible to voluntarily control a state of consciousness that is characterized by a loss of volition and attentional guidance. Here we show that the expectation that sleep will come to an end at a certain time induces a marked increase in the concentration of the hormone adrenocorticotriopin(促肾上腺皮质激素) in the blood one hour before waking. The regulation of adrenocorticotropin release during nocturnal sleep is therefore not confined to daily rhythms; (46) (47) Normally, the release of adrenocorticotropin and cortisol(皮质醇)increases during late stages of sleeping, reaching a daily maximum at the time of spontaneous waking. Adrenocorticotropin and cortisol are also released from the pituitary-adrenal system in a major adaptive response to stress, and are secreted in anticipation of stressful events. We investigated whether the increase in the secretion of pituitary-adrenal hormones during the late stages of sleeping in part reflects anticipation of the ’stress’ of the waking phase. (48) We made recordings of electroencephalogram, electrooculogram and electromyogram throughout the night, and took blood samples every 15 minutes to determine plasma concentrations of adrenocorticortropin and cortisol. Lights were turned off at midnight, after subjects had been told they would be woken at either 6:00 (’short sleep’, on one night) or 9:00(’long sleep’, on the other two nights). On one of the long-sleep nights they were woken at 9:00 as they expected, but on the other night they were instead woken at 6:00 (’surprise’)under the pretence of a technical problem. (49) We interviewed the volunteers at the end of the experiments, and found that all but one of the subjects had expected to be woken up at the specified time. The order of the three experimental nights was balanced across subjects, with five subjects starting with short sleep, five with long sleep, and five with the surprise condition. The increase in adrenocorticotropin release before the expected time of waking indicates that anticipation, which is generally considered to be a unique characteristic of the regulation of conscious action, pervades sleep (50) The regulation of adrenocorticotropin release points to a mechanism that quickly adjusts endocrine activity to sharp changes in the duration.A. The regulation of sleep termination has been thought to embedded in a daily rhythm controlling in paralleling the release of pituitary and adrenal hormones.B. Fifteen healthy volunteers with regular sleep-wake rhythms were studied during three nights. C. It also reflects a preparatory process in anticipation of the end of sleepD. After being woken, subjects stayed in bed for another three hoursE. The anticipatory adrenocorticotropin increase may also facilitate spontaneous wakingF. About 10 million Americans consult doctors sleep problems each year 47.（）
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Some people can quite accurately time the end of their night’s sleep at will, without using an alarm clock, demonstrating that it is possible to voluntarily control a state of consciousness that is characterized by a loss of volition and attentional guidance. Here we show that the expectation that sleep will come to an end at a certain time induces a marked increase in the concentration of the hormone adrenocorticotriopin(促肾上腺皮质激素) in the blood one hour before waking. The regulation of adrenocorticotropin release during nocturnal sleep is therefore not confined to daily rhythms; (46) (47) Normally, the release of adrenocorticotropin and cortisol(皮质醇)increases during late stages of sleeping, reaching a daily maximum at the time of spontaneous waking. Adrenocorticotropin and cortisol are also released from the pituitary-adrenal system in a major adaptive response to stress, and are secreted in anticipation of stressful events. We investigated whether the increase in the secretion of pituitary-adrenal hormones during the late stages of sleeping in part reflects anticipation of the ’stress’ of the waking phase. (48) We made recordings of electroencephalogram, electrooculogram and electromyogram throughout the night, and took blood samples every 15 minutes to determine plasma concentrations of adrenocorticortropin and cortisol. Lights were turned off at midnight, after subjects had been told they would be woken at either 6:00 (’short sleep’, on one night) or 9:00(’long sleep’, on the other two nights). On one of the long-sleep nights they were woken at 9:00 as they expected, but on the other night they were instead woken at 6:00 (’surprise’)under the pretence of a technical problem. (49) We interviewed the volunteers at the end of the experiments, and found that all but one of the subjects had expected to be woken up at the specified time. The order of the three experimental nights was balanced across subjects, with five subjects starting with short sleep, five with long sleep, and five with the surprise condition. The increase in adrenocorticotropin release before the expected time of waking indicates that anticipation, which is generally considered to be a unique characteristic of the regulation of conscious action, pervades sleep (50) The regulation of adrenocorticotropin release points to a mechanism that quickly adjusts endocrine activity to sharp changes in the duration.A. The regulation of sleep termination has been thought to embedded in a daily rhythm controlling in paralleling the release of pituitary and adrenal hormones.B. Fifteen healthy volunteers with regular sleep-wake rhythms were studied during three nights. C. It also reflects a preparatory process in anticipation of the end of sleepD. After being woken, subjects stayed in bed for another three hoursE. The anticipatory adrenocorticotropin increase may also facilitate spontaneous wakingF. About 10 million Americans consult doctors sleep problems each year 48.（）
Countless people are born with(生来就具有某种特点)the susceptibility to inherit a genetic disease. But scientific progress, especially the art of interfering with(干涉,阻碍) the genetic makeup of the human body, has helped doctors prevent more and more inherited disorders in the last decade.Dr. Thomas Caskey of the Baylor University College of medicine in Houston, Texas, is a pioneer in molecular biology(分子生物学). Through the techniques of genetic engineering(基因工程), he transfers genes from one organism to another. Caskey uses a certain type of virus, called a retrovirus(逆转录病毒), as the vehicle for the gene transfer. He first cripples the virus by removing the portion it needs to reproduce itself. The crippled virus becomes harmless while still being able to deliver a cargo to its destination.The cargo in Caskey’s experiment is the human A-D-A gene, taken from bone marrow. A-D-A stands for(代表) adenosine deaminase(腺苷脱氨酶), an important component of the human immune system. A defect in the A-D-A gene leads to immune deficiency, rendering(致使) the body defenseless against infections. Caskey’s purpose was to see if the human A-D-A gene could repair the defective immune system of a mouse.In the experiment the mouse was given a dose of radiation heavy enough to destroy its immune system. The animal next was injected with the crippled virus carrying the human A-D-A gene. According to Caskey, "the mouse will die within 10 to 14 days unless a successful transfer of bone marrow cells takes place. So we lethally irradiate and subsequently rescue the mouse by bone marrow transplantation(骨髓移植)with the cells that have been infected with the virus." The mouse now carries the human gene that salvaged its immune system.Bone marrow transplantation has an established place in contemporary medical practice. Employed to restore the immune system of certain cancer patients and of people who have been exposed to radiation, bone marrow transplantation works only if there is a good match between donor and recipient.The procedure would be much easier if bone marrow were like blood. People with type O blood are universal donors(万能供体). Their blood may be transfused to those who have different blood types. Unfortunately, there is no such thing as a universal bone-marrow type. Researchers may have found a way, however, to overcome this problem. The solution, if it works, would be to implant the patient with his own, perfectly matching(型配), bone marrow.The idea, as Caskey explains it, is to "correct the patient’s disease with his own ceils, but those cells have added to them a normally functioning gene. "In other words, surgeons would take defective bone-marrow cells from the patient and put them into a laboratory dish where the cells would be exposed to a crippled virus carrying a healthy AD-A gene from a donor. The A-D-A gene would repair the defective cells and then the cells would be reinjected into the patient. Thus, in Caskey words, "the patient would be transplanted by his own ceils containing the added normal gene."The technique sounds deceptively(靠不住地) simple. In reality, though(可是,不过, 然而), it is complex. A number of laboratories have tested various intermediate steps of the process, but, according to Caskey, "no single laboratory has put together the entire technology successfully, and highly reproducibly, to proceed with a gene transfer at-tempt in man."For some time now, the U.S. National Institute of Health has been taking a close look at(仔细,研究) the effectiveness and safety of the procedure, as well as the ethical questions it raises. There doesn’t seem to be much concern about the ethics of gene transfer into a human being to correct a genetic defect.Dr. W. French Anderson of N. I. H. wrote recently that "claims that new organs, designed personalities, master races, or Frankenstein(佛兰肯思泰因，一个创造怪物而自己被它毁灭的医学研究者，英国女作家Mary W.Shelly同名小说中的主角) monsters will be created can be given no credence in the light of(根据,从……来看) what is presently known. "And he added that a well-informed public is the best assurance against any future misuses of genetic engineering. What technique is needed to repair the defective cells with A-D-A gene（）
ZYBAN is a prescription (处方) medicine to help people quit smoking. Studies have shown that more than one third of people quit smoking for at least one month while taking ZYBAN. For many patients, ZYBAN reduces withdrawal symptoms (脱瘾过程中产生的症状) and the strong wish to smoke. 2 ZYBAN should be taken as directed by your doctor. The usual recommended dosing(剂量) is to take one 150-mg tablet in the morning for the first 3 days. On the fourth day, begin taking one 150-mg tablet in the morning and one 150-mg tablet in the early evening. Doses should be taken at least 8 hours apart. 3. For most patients, treatment will last 7 to 12 weeks. Because results vary, it may take longer for some people, Possibly up to 6 months depending on the individual. If you've been smoking for a long time, ZYBAN will help to reduce withdrawal symptoms. It's important to remain on ZYBAN for at least 7 to 12 weeks in order to quit for good. Your doctor should determine when to stop taking ZYBAN 4. It takes about 1 week for ZYBAN to reach the right levels in your body to be effective So, to increase your chance of quitting as much as possible, you should not stop smoking until you have been taking ZYBAN for 1 week. You should set a date to stop smoking during the second week you're taking ZYBAN. 5. The side effects (副作用) associated with ZYBAN are generally mild and often disappear after a few weeks. The most common side effects are dry mouth and difficulty in sleeping. If you have difficulty sleeping, avoid taking your medicine too close to bedtime Paragraph 5 （）
William, who conquered England some 930 years ago, had wealth, power and a ruthless army. Yet although William was stupefyingly rich by the standard of his time, he had nothing remotely resembling a flush toilet. No paper towels, no riding lawn mower. How did he get byHistory books are filled with wealthy people who were practically destitute compared to me, I have tripe-tracked storm window; Croesus did not. Entire nations trembled before Alexander the Great, but he couldn’t buy cat food in bulk. Czar Nicholas Ⅱ lacked a compound-miter saw.Given how much better off I am than so many famous dead people, you’d think I’d be content. The trouble is that, like most people, I compare my prosperity with that of living persons: neighbors, high-school classmates, TV personalities. The covetousness I feel toward my friend Howard’s kitchen is not mitigated by the fact that no French monarch ever had a refrigerator with glass doors.There is really no rising or falling standard of living. Over the centuries people simply find different stuff to feel grumpy about. You’d think that merely not having bubonic plague(腺鼠疫) would put us in a good mood. But no, we want a hot tub too.Of course, one way to achieve happiness would be to realize that even by contemporary standards the things I own are pretty nice. My house is smaller than the houses of many investment bankers’, but even so it has a lot more rooms than my wife’s and I can keep clean. Besides, to people looking back at our era from a century or two in the future, those bankers’ fancy counter tops and my own worn Formica(福米加塑料桌面)will seem equally shabby. I can’t keep up with my neighbor right now. but just wait. Which of the following statements is NOT true（）
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