FLOODING AND ITS IMPACT IELTS ACADEMIC READINGS FOR EXAM PRACTICE VOLUME 2 EXAM READING 33

 

IELTS ACADEMIC READINGS FOR EXAM PRACTICE VOLUME 2 EXAM READING 33 READING PASSAGE 1

 

FLOODING AND ITS IMPACT Floods can occur in rivers when the flow rate exceeds the capacity of the river channel, particularly at bends or meanders in the waterway. Floods often cause damage to homes and businesses if they are in the natural flood plains of rivers. While riverine flood damage can be eliminated by moving away from rivers and other bodies of water, people have traditionally lived and worked by rivers because the land is usually flat and fertile and because rivers provide easy travel and access to commerce and industry. A Fire and flood are two of humanity’s worst nightmares. People have,therefore,always sought to control them. Forest fires are snuffed out quickly. The flow of rivers is regulated by weirs and dams. At least, that is how it used to be. But foresters have learned that forests need fires to clear out the brash and even to get seeds to germinate. And a similar revelation is now – dawning on hydrologists. Rivers – and the ecosystems they support – need floods. That is why a man-made torrent has been surging down the Grand Canyon. By Thursday March 6th it was running at full throttle, which was expected to be sustained for 60 hours. B Floods once raged through the canyon every year. Spring Snow from as far away as Wyoming would melt and swell the Colorado river to a flow that averaged around 1,500 cubic metres (50,000 cubic feet) a second. Every eight years or so, that figure rose to almost 3,000 cubic metres. These floods infused the river with sediment, carved its beaches and built its sandbars. C However, in the four decades since the building of the Glen Canyon dam, just upstream of the Grand Canyon, the only sediment that it has collected has come from tiny, undammed tributaries. Even that has not been much use as those tributaries are not powerful enough to distribute the sediment in an ecologically valuable way. D This lack of flooding has harmed local wildlife. The humpback chub,for example, thrived in the rust-redwaters of the Colorado. Recently, though, its population has crashed. At first sight, it looked as if the reason was that the chub were being eaten by trout introduced for sport fishing in the mid-20th century. But trout and chub co-existed until the Glen Canyon dam was built, so something else is going on. Steve Gloss, of the United States’ Geological Survey (USGS), reckons that the chub’s decline is the result of their losing their most valuable natural defense, the Colorado’s rusty sediment. The chub were well adapted to the poor visibility created by the thick, red water which gave the river its name, and depended on it to hide from predators. Without the cloudy water the chub became vulnerable. E And the chub are not alone. In the years since the Glen Canyon dam was built, several species have vanished  altogether. These include the Colorado pike-minnow, the razorback sucker and the round-tail chub. Meanwhile, aliens including fathead minnows, channel catfish and common carp, which would have been hard, put to survive in the savage waters of the undammed canyon, have move din. F So flooding is the obvious answer. Unfortunately, it is easier said than done. Floods were sent down the Grand Canyon in 1996 and 2004 and the results were mixed. In 1996 the flood was allowed to go on too long. To start with,all seemed well. The floodwaters built up sandbanks and infused the river with sediment. Eventually, however, the continued flow washed most of the sediment out of the canyon. This problem was avoided in 2004, but unfortunately, on that occasion, the volume of sand available behind the dam was too low to rebuild the sandbanks. This time, the USGS is convinced that things will be better. The amount of sediment available is three times greater than it was in 2004. So if a flood is going to do some good, this is the time to unleash one. G Even so, it may turn out to be an empty gesture. At less than 1,200 cubic metres a second, this flood is smaller than even an average spring flood, let alone one of the mightier deluges of the past. Those glorious inundations moved massive quantities of sediment through the Grand Canyon,wiping the slate dirty, and making a muddy mess of silt and muck that would make modern river rafters cringe.   Questions 1-7 Do the following statements agree with the information given in Reading Passage 1? In boxes 1-7 on your answer sheet, write   TRUE if the statement is true FALSE if the statement is false NOT GIVEN if the information is not given in the passage   1 Damage caused by fire is worse than that caused by flood. 2 The flood peaks at almost 1500 cubic meters every eight years. 3 Contribution of sediments delivered by tributaries has little impact. 4 Decreasing number of chubs is always caused by introducing of trout since mid 20th century. 5 It seemed that the artificial flood in 1996 had achieved success partly at the very beginning. 6 In fact, the yield of artificial flood water is smaller than an average natural flood at present. 7 Mighty floods drove fast moving flows with clean and high quality water.   Questions 8-13 Complete the summary below. Choose NO MORE THAN TWO WORDS from the passage for each answer. Write your answers in boxes 8-13 on your answer sheet.   The Eco-Impact of the Canyon Dam Floods are people’s nightmare. In the past, canyon was raged by flood every year. The snow from far Wyoming would melt in the season of 8___________________ and caused a flood flow peak in Colorado river. In the four decades after people built the Glen Canyon dam, it only could gather 9___________________ together from tiny, undammed tributaries.   Humpback chub population on reduced, why? Then, several species disappeared including Colorado pike-minnow, 10___________________  and the round-tail chub. Meanwhile, some moved in such as fathead minnows, channel catfish and 11___________________. The non-stopped flow leaded to the washing away of the sediment out of the canyon, which poses great threat to the chubs because it has poor 12___________________ away from predators. In addition, the volume of 13___________________  available behind the dam was too low to rebuild the bars and flooding became more serious.

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IELTS ACADEMIC READINGS FOR EXAM PRACTICE VOLUME 2 EXAM READING 32

 

IELTS ACADEMIC READINGS FOR EXAM PRACTICE VOLUME 2 EXAM READING 32 READING PASSAGE 3

 

A While it may not be possible to completely age-proof our brains, a brave new world of anti-aging research shows that our gray matter may be far more flexible than we thought. So no one, no matter how old, has to lose their mind. The brain has often been called the three-pound universe. It’s our most powerful and mysterious organ, the seat of the self, laced with as many billions of neurons as the galaxy has stars. No wonder the mere notion of an aging, failing brain—and the prospect of memory loss, confusion, and the unraveling of our personality—is so terrifying. As Mark Williams, M.D., author of The American Geriatrics Society’s Complete Guide to Aging and Health, says, “The fear of dementia is stronger than the fear of death itself.” Yet the degeneration of the brain is far from inevitable. ”  Its design features are such that it should continue to function for a lifetime,” says Zaven Khachaturian, Ph.D., director of the Alzheimer1s Association1s Ronald and Nancy Reagan Research Institute. “There’s no reason to expect it to deteriorate with age, even though many of us are living longer lives.” In fact, scientists ‘ view of the brain1s potential is rapidly changing, according to Stanford University neuroscientist Robert Sapolsky, Ph.D.   “Thirty-five years ago we thought Alzheimer1 s disease was a dramatic version of normal aging. Now we realize it1s a disease with a distinct pathology. In fact, some people simply don’t experience any mental decline, so we’ve begun to study them.” Antonio Damasio, M.D., Ph.D., head of the Department of Neurology at the University of Iowa and author of Descartes’ Error, concurs. “Older people can continue to have extremely rich and healthy mental lives.’ B The seniors were tested in 1988 and again in 1991. Four factors were found to be related to their mental fitness: levels of education and physical activity, lung function, and feelings of self-efficacy “Each of these elements alters the way our brain functions,“ says Marilyn Albert, Ph.D. , of Harvard Medical School, and colleagues from Yale, Duke, and Brandeis Universities and the Mt. Sinai School of Medicine, who hypothesizes that regular exercise may actually stimulate blood flow to the brain and nerve growth, both of which create more densely branched neurons, rendering the neurons stronger and better able to resist disease. Moderate aerobic exercise, including long brisk walks and frequently climbing stairs, will accomplish this. C Education also seems to enhance brain function. People who have challenged themselves with at least a college education may actually stimulate the neurons in their brains. Moreover, native intelligence may protect our brains. It’s possible that smart people begin life with a greater number of neurons, and therefore have a greater reserve to fall back on if some begin to fail. “If you have a lot of neurons and keep them busy, you may be able to tolerate more damage to your brain before it shows,” says Peter Davies, M.D., of the Albert Einstein College of Medicine in the Bronx, New York. Early linguistic ability also seems to help our brains later in life. A recent study in the New England Journal of Medicine looked at 93 elderly nuns and examined the autobiographies they had written 60 years earlier, just as they were joining a convent. The nuns whose essays were complex and dense with ideas remained sharp into their eighties and nineties. D Finally, personality seems to play an important role in protecting our mental prowess. A sense of self-efficacy may protect our brain, buffeting it from the harmful effects of stress. According to Albert, there’ s evidence that elevated levels of stress hormones may harm brain cells and cause the hippocampus—a small seahorse-shaped organ that1s a crucial moderator of memory—to atrophy. A sense that we can effectively chart our own course in the world may retard the release of stress hormones and protect us as we age. “It’ s not a matter of whether you experience stress or not, ” Albert concludes, “it’s your attitude toward it. ” Reducing stress by meditating on a regular basis may buffer the brain as well. It also increases the activity of the brain’ s pineal gland, the source of the antioxidant hormone melatonin, which regulates sleep and may retard the aging process. Studies at the University of Massachusetts Medical Center and the University of Western Ontario found that people who meditated regularly had higher levels of melatonin than those who took 5-milligram supplements Another study, conducted jointly by Maharishi International University, Harvard University, and the University of Maryland, found that seniors who meditated for three months experienced dramatic improvements in their psychological well-being, compared to their non-meditative peers. E Animal studies confirm that both mental and physical activity boost brain fitness. At the Beckman Institute for Advanced Science and Technology in Urbana, Illinois， psychologist William Greenough, Ph. D., let some rats play with a profusion of toys. These rodents developed about 25 percent more connections between their neurons than did rats that didn’t get any mentally stimulating recreation. In addition, rats that exercised on a treadmill developed more capillaries in specific parts of their brains than did their sedentary counterparts. This increased the blood flow to their brains. “Clearly the message is to do as many different flyings as possible,” Greenough says. F It’s not just scientists who are catching the anti-aging fever. Walk into any health food store, and you111 find nutritional formulas —with names like Brainstorm and Smart ALEC—that claim to sharpen mental ability. The book Smart Drugs & Nutrients, by Ward Dean, M.D., and John Morgenthaler, was self-published in 1990 and has sold over 120,000 copies worldwide. It has also spawned an underground network of people tweaking their own brain chemistry with nutrients and drugs—the latter sometimes obtained from Europe and Mexico. Sales of ginkgo —an extract from the leaves of the 200-million-year-old ginkgo tree, which has been shown in published studies to increase oxygen in the brain and ameliorate symptoms of Alzheimer‘ s disease—are up by 22 percent in the last six months alone, according to Paddy Spence, president of SPINS, a San Francisco-based market research firm. Indeed, products that increase and preserve mental performance are a small but emerging segment of the supplements industry, says Linda Gilbert, president of Health Focus, a company that researches consumer health trends. While neuroscientists like Khachaturian liken the use of these products to the superstition of tossing salt over your shoulder, the public is nevertheless gobbling up nutrients that promise cognitive enhancement. Questions 27-30 Choose the Four correct letters among A-G. Write your answers in boxes 27-30 on your answer sheet. Which of the FOUR situations or conditions assisting the Brains’ function? A. Preventive treatment against Alzheimer’s disease B. Doing active aerobic exercise and frequently climbing stairs C. High levels of education D. Early verbal or language competence training E. Having more supplements such as ginkgo tree F. Participate in more physical activity involving in stimulating tasks G. Personality and feelings of self-fulfillment Questions 31-38 Use the information in the passage to match the people (listed A-G) with opinions or deeds below. Write the appropriate letters A-G in boxes 32-39 on your answer sheet. NB you may use any latter more than once A. Zaven Khachaturian B. William Greenough C. Marilyn Albert D. Robert Sapolsky E. Linda Gilbert F. Peter Davies G. Paddy Spence   31 Alzheimer’s was probably a kind of disease rather than a normal aging process. 32 Keeping neurons busy, people may be able to endure more harm to your brain 33 Regular exercises boost blood flow to the brain and increase anti-disease disability. 34 Significant increase of Sales of ginkgo has been shown. 35 More links between their neurons are found among stimulated animals. 36 Effectiveness of the use of brains supplements products can be of little scientific proof. 37 Heightened levels of stress may damage brain cells and cause part of brain to deteriorate. 38 Products that upgrade and preserve mental competence are still a newly developing industry. Questions 39 Choose the correct letters among A-D. Write your answers in box 39 on your answer sheet. 39 According to the passage, what is the most appropriate title for this passage? A Making our minds last a lifetime B amazing pills of the ginkgo C how to stay healthy in your old hood D more able a brain and neurons

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