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Set Your Body’s Time Clock Our Body Operates Like a Clock [A] As the first rays of sunlight filter over the hills of California’s Silicon Valley, Charles Winget opens his eyes. It is barely 5 a.m., but Winget is raring (渴望) to go. Meanwhile, his wife pulls up the covers and buries her face under the pillow. "For the past fifteen years," says Winget, "We’ve hardly ever gotten up together." [B] The Wingets’ situation is not uncommon. Our bodies operate with the complexity of clocks, and like clocks, we all run at slightly different speeds. Winget is a morning person. His wife is not at her best until after nightfall. [C] Behavioral scientists long attributed such differences to personal eccentricities or early conditioning. This thinking was challenged in the late 1950s by a theory labeled chronobiology by physician- biologist Franz Halberg. In a Harvard University laboratory, Dr. Halberg found that certain blood cells varied predictably in number, depending on the time of day they were drawn from the body. The cell count was higher at a given time of day and lower 12 hours later. He also discovered that the same patterns could be detected in heart and metabolic rates and body temperature. [D] Halberg’s explanation: instead of performing at a steady, unchanging rate, our systems function on an approximately 25-hour cycle. Sometimes we are accelerating, sometimes slowing down. We achieve peak efficiency for only a limited time each day. Halberg dubbed these bodily cadences "circadian rhythms". [E] Much of the leading work in chronobiology is sponsored today by the National Aeronautics and Space Administration. Charles Winget, a NASA research physiologist and authority on circadian rhythms, says that circadian principles have been applied to astronauts’ work schedules on most of the space-shuttle flights. [F] The space-age research has many useful applications here on earth. Chronobiologists can tell you when to eat and still lose weight, what time of day you’re best equipped to handle the toughest challenges, when to go to the dentist with your highest threshold of pain and when to exercise for maxi-mum effect. Says Winget, "It’s a biological law of human efficiency: to achieve your best with the least effort, you have to coordinate the demands of your activities with your biological capacities." How to Figure Out Your Body’s Patterns [G] Circadian patterns can be made to work for you. But you must first learn how to recognize them. Winget and his associates have developed the following approach to help you figure out your body’s patterns. [H] Take your temperature one hour after getting up in the morning and then again at four-hour intervals throughout the day. Schedule your last reading as close to bedtime as possible. You should have five readings by the end of the day. [I] Now add your first, third and fifth readings and record this total. Then add your second and fourth readings and subtract this figure from the first total. That number will be an estimate of your body temperature in the middle of the night—consider it your sixth reading. [J] Now plot all six readings on graph paper. The variations may seem minuscule (极小的)—only one-tenth of a degree in some cases—but they are significant. You’ll probably find that your temperature will begin to rise between 3 a.m. and 6 a.m., reaching a peak sometime in the late morning or early afternoon. By evening the readings start to drop. They will steadily decline, reaching their nadir (最低点) at around 2 a.m. Learn to Use Your Body’s Pattern [K] Of course, individual variations make all the difference. At what hour is your body temperature on the rise When does it reach its highest point Its lowest Once you have familiarized yourself with you patterns, you can take advantage of chronobiology techniques to improve your health and productivity. [L] We do our best physical work when our rhythms are at their peak. In most people, this peak lasts about four hours. Schedule your most taxing (费力的) activities when your temperature is highest. [M] For mental activities, the timetable is more complicated. Precision tasks, such as mathematical work are best tackled when your temperature is on the rise. For most people, this is at 8 or 9 a.m. By contrast reading and reflection are better pursued between 2 and 4 p.m., the time when body tempera-ture usually begins to fall. [N] Breakfast should be your largest meal of the day for effective dieting. Calories burn faster one hour after we wake up than they do in the evening. During a six-year research project known as the Army Diet Study, Dr.Halberg, chronobiologist Robert Sothern and research associate Erna Halberg monitored the food intake of two groups of men and women. Both ate only one 2000-calorie meal a day, but one group ate their meal at breakfast and the other at dinner. "All the subjects lost weight eating breakfast," states Sothern. "Those who ate dinner either maintained or gained weight." [O] If foods are processed differently at different times of day, certainly caffeine, alcohol and medicines will be too. Aspirin compounds, for example, have the greatest potency (力量) in the morning, between 7 and 8. (So does alcohol.) They are least effective between 6 p.m. and midnight. Caffeine has the most impact around 3 in the afternoon. Charles Walker, dean of the College of Pharmacy at Florida A & M University, explains, "Stimulants are most effective when you are normally active, and sedatives (镇静物) work best when you’re naturally sedate or asleep." [P] Knowing your rhythms can also help overcome sleep problems. Consult your body-temperature chart. Your bedtime should coincide with the point at which your temperature is lowest. This is between 11 p.m. and 2 a.m. for most people. [Q] Dr.Michael Thorpy of the Sleep-Wake Disorders Center at Montefiore Medical Center in New York City offers other circadian sleep tips: go to bed at the same time every night and get up at the same time every morning, even on weekends. "Irregularity in sleep and waking times is the greatest cause of sleep problems," Dr. Thorpy says. The best way to recover from a bad night’s sleep is simply to resume your normal cycle. Beware of sleeping pills. "Most sleeping pills won’t work for periods longer than two weeks," warns Dr. Thorpy. And there is real danger of drug accumulation in the blood. [R] Visit a doctor or dentist as early in the day or as late in the evening as possible, since your highest pain threshold is between 8 p.m. and 8 a.m. [S] Winget and fellow NASA chronobiologist Charles DeRoshia also offer advice to diminish the debilitating effects of jet lag: a week or so before departure begin adjusting your daily activities so that they coincide with the time schedule of your destination. Eat a small, high-protein, low-carbo-hydrate meal just before your trip. Get plenty of sleep in the days before your trip. In flight, eat very little, drink lots of water and avoid alcohol and caffeinated drinks. When you arrive, walk around, talk to people, try to adapt to your environment. Before retiring, have a light meal, high in carbohydrates. Take a warm bath. [T] Knowing your body’s patterns is no guarantee of good health. But what chronobiology reveals is the importance of regularity in all aspects of your life and of learning to act in synchronization with your body’s natural rhythms. When your temperature is highest, you’d better do some physical work such as move cargo.
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Of 100 billion nerve cells in the human brain, how many form after birth For years, the official answer was "zero". Scientists thought people were born with all the neurons they’d ever have. But from 1980s, biologists overturned that doctrine, finding a reservoir of stem cells that became fresh neurons in two parts of the brains of adult birds, monkeys and humans. Those discoveries were stunning, but the next seemed to top them all. In 1999, psychologist Elizabeth Gould reported large numbers of new nerve cells in a third of the monkey brain, hinting that the same part in humans—the neocortex, which lets us reason and remember—was regenerating, too. If she was right, scientists would have to revise almost all their ideas about human memory, and doctors might someday find a way to treat Alzheimer’s patients by simply turning on the neural-construction equipment. The birth of new nerve cells, or "neurogenesis", is now confirmed in the original two parts of human brain, the hippocampus and olfactory bulb. But for the neocortex, the no-neurons theory lives— and it’s just gotten major boost. Until December, Gould’s study stood alone and unverified. Two neuroscientists have repeated her work in Science, but not her results. Where Gould saw new nerve cells in the neocortex, Rakic and Konnack see only glial cells, the "glue" that supports neurons. But they do spot new nerve cells in the other two areas. In a January review in Nature Neuroscience, Rakic charges Gould’s work with technical problems. Focusing on what appeared to be 100 new neurons, Rakic and Kornack found that every one was merely a new glial cell hiding behind an old neuron. Gould has a cross-sectioned image from her own study that she says shows one cell marked as new—and it’s clearly a neuron. But Rakic has an answer for that, too. The method that identified the cells as "new" finds DNA synthesis, which can happen in cells that aren’t actually dividing. Rakic says Gould’s tests were too sensitive, tagging "new" neurons that weren’t. Gould responses that Rakic’s methods just weren’t sensitive enough. But even she can’t explain why that might be. Rakic’s study squares with the idea that memory cornes not from new nerve cells but from chemicals in the spaces between old ones. Gould’s team are circulating response to Rakic and Kornack and recreating two studies side by side to see if small differences in methods are to blame. Others are also redoing the tests; a Japanese team’s unpublished results echoes Rakic’s, while another team’s support Gould’s. Meanwhile work on less controversial new neurons marches forward. Neuroscientist Fred Gage, who’s just wrapped up a study of the function of new hippocampus nerve cells, says that’s as it should be. Still, until more studies confirm Rakic and Komack, he’ll keep a close eye on the neocortex debate. What can we know about Rakic’s study
The use of deferential (敬重的) language is symbolic of the Confucian ideal of the woman, which dominates conservative gender norms in Japan. This ideal presents a woman who withdraws quietly to the background, subordinating her life and needs to those of her family and its male head. She is a dutiful daughter, wife, and mother, master of the domestic arts. The typical refined Japanese woman excels in modesty and delicacy; she "treads softly (谨言慎行) in the world" elevating feminine beauty and grace to an art form. Nowadays, it is commonly observed that young women are not conforming to the feminine linguistic (语言的) ideal. They are using fewer of the very deferential "women’s" forms, and even using the few strong forms that are known as "men’s". This, of course, attracts considerable attention and has led to an outcry in the Japanese media against the defeminization of women’s language. Indeed, we didn’t hear about "men’s language" until people began to respond to girls’ appropriation of forms normally reserved for boys and men. There is considerable sentiment about the "corrnption" of women’s language —which of course is viewed as part of the loss of feminine ideals and morality—and this sentiment is crystallized by nationwide opinion polls that are regularly carried out by the media. Yoshiko Matsumoto has argued that young women probably never used as many of the highly deferential forms as older women. This highly polite style is no doubt something that young women have been expected to "grow into" —after all, it is a sign not simply of femininity, but of maturity and refinement, and its use could be taken to indicate a change in the nature of one’s social relations as well. One might well imagine little girls using exceedingly polite forms when playing house or imitating older women—in a fashion analogous to little girls’ use of a high-pitched voice to do "teacher talk" or "mother talk" in role play. The fact that young Japanese women are using less deferential language is a sure sign of change —of social change and of linguistic change. But it is most certainly not a sign of the "masculization" of girls. In some instances, it may be a sign that girls are making the same claim to authority as boys and men, but that is very different from saying that they are trying to be "masculine". Katsue Reynolds has argued that girls nowadays are using more assertive language strategies in order to be able to compete with boys in schools and out. Social change also brings not simply different positions for women and girls, but different relations to life stages, and adolescent girls are participating in new subcultural forms. Thus what may, to an older speaker, seem like "masculine" speech may seem to an adolescent like "liberated" or "hip" speech. The author believes that the use of assertive language by young Japanese women is ______.
Of 100 billion nerve cells in the human brain, how many form after birth For years, the official answer was "zero". Scientists thought people were born with all the neurons they’d ever have. But from 1980s, biologists overturned that doctrine, finding a reservoir of stem cells that became fresh neurons in two parts of the brains of adult birds, monkeys and humans. Those discoveries were stunning, but the next seemed to top them all. In 1999, psychologist Elizabeth Gould reported large numbers of new nerve cells in a third of the monkey brain, hinting that the same part in humans—the neocortex, which lets us reason and remember—was regenerating, too. If she was right, scientists would have to revise almost all their ideas about human memory, and doctors might someday find a way to treat Alzheimer’s patients by simply turning on the neural-construction equipment. The birth of new nerve cells, or "neurogenesis", is now confirmed in the original two parts of human brain, the hippocampus and olfactory bulb. But for the neocortex, the no-neurons theory lives— and it’s just gotten major boost. Until December, Gould’s study stood alone and unverified. Two neuroscientists have repeated her work in Science, but not her results. Where Gould saw new nerve cells in the neocortex, Rakic and Konnack see only glial cells, the "glue" that supports neurons. But they do spot new nerve cells in the other two areas. In a January review in Nature Neuroscience, Rakic charges Gould’s work with technical problems. Focusing on what appeared to be 100 new neurons, Rakic and Kornack found that every one was merely a new glial cell hiding behind an old neuron. Gould has a cross-sectioned image from her own study that she says shows one cell marked as new—and it’s clearly a neuron. But Rakic has an answer for that, too. The method that identified the cells as "new" finds DNA synthesis, which can happen in cells that aren’t actually dividing. Rakic says Gould’s tests were too sensitive, tagging "new" neurons that weren’t. Gould responses that Rakic’s methods just weren’t sensitive enough. But even she can’t explain why that might be. Rakic’s study squares with the idea that memory cornes not from new nerve cells but from chemicals in the spaces between old ones. Gould’s team are circulating response to Rakic and Kornack and recreating two studies side by side to see if small differences in methods are to blame. Others are also redoing the tests; a Japanese team’s unpublished results echoes Rakic’s, while another team’s support Gould’s. Meanwhile work on less controversial new neurons marches forward. Neuroscientist Fred Gage, who’s just wrapped up a study of the function of new hippocampus nerve cells, says that’s as it should be. Still, until more studies confirm Rakic and Komack, he’ll keep a close eye on the neocortex debate. What was the problem with Gould’s research result according to Rakic
Of 100 billion nerve cells in the human brain, how many form after birth For years, the official answer was "zero". Scientists thought people were born with all the neurons they’d ever have. But from 1980s, biologists overturned that doctrine, finding a reservoir of stem cells that became fresh neurons in two parts of the brains of adult birds, monkeys and humans. Those discoveries were stunning, but the next seemed to top them all. In 1999, psychologist Elizabeth Gould reported large numbers of new nerve cells in a third of the monkey brain, hinting that the same part in humans—the neocortex, which lets us reason and remember—was regenerating, too. If she was right, scientists would have to revise almost all their ideas about human memory, and doctors might someday find a way to treat Alzheimer’s patients by simply turning on the neural-construction equipment. The birth of new nerve cells, or "neurogenesis", is now confirmed in the original two parts of human brain, the hippocampus and olfactory bulb. But for the neocortex, the no-neurons theory lives— and it’s just gotten major boost. Until December, Gould’s study stood alone and unverified. Two neuroscientists have repeated her work in Science, but not her results. Where Gould saw new nerve cells in the neocortex, Rakic and Konnack see only glial cells, the "glue" that supports neurons. But they do spot new nerve cells in the other two areas. In a January review in Nature Neuroscience, Rakic charges Gould’s work with technical problems. Focusing on what appeared to be 100 new neurons, Rakic and Kornack found that every one was merely a new glial cell hiding behind an old neuron. Gould has a cross-sectioned image from her own study that she says shows one cell marked as new—and it’s clearly a neuron. But Rakic has an answer for that, too. The method that identified the cells as "new" finds DNA synthesis, which can happen in cells that aren’t actually dividing. Rakic says Gould’s tests were too sensitive, tagging "new" neurons that weren’t. Gould responses that Rakic’s methods just weren’t sensitive enough. But even she can’t explain why that might be. Rakic’s study squares with the idea that memory cornes not from new nerve cells but from chemicals in the spaces between old ones. Gould’s team are circulating response to Rakic and Kornack and recreating two studies side by side to see if small differences in methods are to blame. Others are also redoing the tests; a Japanese team’s unpublished results echoes Rakic’s, while another team’s support Gould’s. Meanwhile work on less controversial new neurons marches forward. Neuroscientist Fred Gage, who’s just wrapped up a study of the function of new hippocampus nerve cells, says that’s as it should be. Still, until more studies confirm Rakic and Komack, he’ll keep a close eye on the neocortex debate. What contribution was made by Gould to the research of nerve cells
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