2015年全国职称英语考试通关必备利器理工类A级教材牛津英语同义词字典版

M Climate Change Poses Major Risks for Unprepared Cities A new examination of urban policies has been carried out recently by Patricia Romero Lankao. She is a sociologist specializing in climate change and urban development. She warns that many of the world’s fast -growing urban areas, especially in developing countries, will likely1 suffer from the impacts of changing climate. Her work also concludes that most cities are failing to reduce emissions of carbon dioxide and other greenhouse gases. These gases are known to affect the atmosphere. “Climate change is a deeply local issue and poses profound threats to the growing cities of the world,” says Romero Lankao. “But too few cities are developing effective strategies to protect their residents. ” Cities are major sources of greenhouse gases. And urban populations are likely to be among those most severely affected by future climate change. Lankao’s findings3 highlight ways in which city-residents are particularly vulnerable, and suggest policy interventions that could offer immediate and longer-term benefits The locations and dense construction patterns of cities often place their populations at greater risk for natural disasters. Potential threats associated with climate include storm surges and prolonged hot weather. Storm surges can flood coastal areas and prolonged hot weather can heat heavily paved cities more than surrounding areas. The impacts of such natural events can be more serious in an urban environment. For example, a prolonged heat wave can increase existing levels of air pollution, causing widespread health problems. Poorer neighborhoods that may lack basic facilities such as drinking water or a dependable network of roads, are especially vulnerable to natural disasters. Many residents in poorer countries live in substandard housing without access to reliable drinking water, roads and basic services. Local governments,therefore,should take measures to protect their residents. “Unfortunately, they tend to move towards rhetoric rather than meaningful responses,” Romero Lankao writes. “They don’t impose construction standards that could reduce heating and air conditioning needs. They don’t emphasize mass transit and reduce automobile, use. In fact, many local governments are taking a hands-off approach.” Thus, she urges them to change their idle policies and to take strong steps to prevent the harmful effects of’ climate change on cities. Free Statins With Fast Food Could Neutralize Heart Risk Fast food outlets could provide statin drugs free of charge so that customers can reduce the heart disease dangers of fatty food, researchers at Imperial College London suggest in a new study. Statins reduce the amount of unhealthy “LDL ” cholesterol in the blood. A wealth of trial data4 has proven them to be highly effective at lowering a person ’s heart attack risk In a paper published in the American Journal of Cardiology, Dr Darrel Francis and colleagues calculate that the reduction in heart attack risk offered by a statin is enough to offset the increase in heart attack risk from eating a cheeseburger and drinking a milkshake.Dr Francis, from the National Heart and Lung Institute at Imperial College London, who is the senior author of the study, said: “Statins don ’t cut out all of the unhealthy effects of cheeseburgers and French fries. It ’s better to avoid fatty food altogeth er. But we’ve worked out that in terms of your possibility of having a heart attack, taking astatin can reduce your risk to more or less the same degree as a fast food meal increases it. ”It ’s ironic that people are free to take as many unhealthy condiments in fast food outlets as they like, but statins, which are beneficial to heart health, have to be prescribed. It makes sense to make risk-reducing statins available just as easily as the unhealthy condiments that are provided free of charge. It would cost less than 5 pence per customer —— not much different to a sachet of sugar, “ Dr Francis said.When people engage in risky behaviours likedriving or smoking, they ’re encouraged to take measures that lower their risk, like wearing a seatbelt or choosing cigarettes with filters. Taking a stain is a rational way of lowering some of the risks of eating a fatty meal.Better Solar Energy Systems: More Heat, More LightSolar photovoltaic thermal energy systems, or PVTs, generate both heat and electricity, but until now they haven’t been very good at the heat-generating part compared to a stand-alone solar thermal collector. That’s because they operate at low temperatures to cool crystalline silicon solar cells, which lets the silicon generate more electricity but isn’t a very efficient way to gather heat. That ’s a problem of economics. Good solar hot-water systems can harvest much more energy than a solar-electric system at a substantially lower cost. And it ，s also a space problem ：photovoltaic cells can take up all the space on the roof, leaving little room for thermal applications. In a pair of studies, Joshua Pearce, an associate professor of materials science and engineering, has devised a solution in the form of a better PVT made with a different kind of silicon. His research collaborators are Kunal Girotra from ThinSilicon in California and Michael Pathak and Stephen Harrison from Queen’s Universi ty, Canada." Most solar panels are made with crystalline silicon ， but you can also make solar cells out of amorphous silicon,commonly known as thin-film silicon. They don ’t create as much electricity, but they are lighter, flexible, and cheaper. And, because they require much less silicon, they have a greener footprint. Unfortunately ，thin-film silicon solar cells are vulnerable to some bad-news physics in the form of the Staebler-Wronski effect.M “That means that their efficiency drops when youexpose them to light —pretty much the worstpossible effect for a solar cell,”Pearce explains，which is one of the reasons thin- film solar panelsmake up only a small fraction of the market.However, Pearce and his team found a way toengineer around the Staebler-Wronski effect byincorporating thin-film silicon in a new tpye ofPVT. You don’t have to cool down thin-filmsilicon to make it work. In fact，Pearce’s groupdiscovered that by heating it to solar-thermaloperating temperatures，near the boiling point ofwater, they could make thicker cells that largelyovercame the Staebler-Wronski effect. When theyapplied the thin-film silicon directly to a solarthermal energy collector, they also found that bybaking the cell once a day，they boosted the solarcell’s electrical efficiency by over 10 percent.Sharks Perform a Service for Earth’s WatersyIt is hard to get people to think of sharks asanything but a deadly enemy. They are thought toattack people frequently. But these fish perform avaluable ser vice for earth’s waters and for humanbeings. Yet business and sport fishing3 arethreatening their existence. Some sharks are at riskof disappearing from earth.Warm weather may influence both fish and sharkactivity. Many fish swim near coastal areasbecause of their warm waters. Experts say sharksmay follow the fish into the same areas,wherepeople also swim. In fact, most sharks do notpurposely charge at or bite humans. They arethought to mistake a person for a sea animal, suchas a seal or sea lion. That is why people should notswim in the ocean when the sun goes down orcomes up. Those are the times when sharks arelooking for food. Experts also say that brightcolors and shiny jewelry may cause sharks toattack.A shark has an extremely good sense of smell4. Itcan find small amounts of substances in water,such as blood, body liquids and chemicalsproduced by animals. These powerful senses helpsharks find their food. Sharks eat fish, anyother sharks, and plants that live in the ocean.Medical researchers want to learn more about theshark’s body defense and immune systems againstdisease. Researchers know that sharks recoverquickly from injuries. They study the shark inhopes of finding a way to fight human disease.Sharks are impo rtant for the world’s oceans. Theyeat injured and diseased fish. Their huntingactivities mean that the numbers of other fish inocean waters do not become too great. Thisprotects the plants and other forms of life that existin the oceans.“Liquefaction” Key to Much of JapaneseEarthquake DamageThe massive subduction zone earthquake in Japancaused a significant level of soil “liquefaction” thathas surprised researchers with its widespreadseverity, a new analysis shows.We’ve seen localized examples o f soil liquefactionas extreme as this before, but the distance andextent of damage in Japan were unusually severe,”said Scott Ashford, a professor of geotechnicalengineering at Oregon State University. “Entirestructures were tilted and sinking into thesediments,” Ashford said. “The shifts in soildestroyed water, drain and gas pipelines, cripplingthe utilities and Infrastructure these communitiesneed to function. We saw some places that sank asmuch as four feet. ”Some degree of soil liquefaction is common inalmost any major earthquake. It’s a phenomenon inwhich soils soaked with water, particularly recentsediments or sand, can lose much of their strengthand flow during an earthquake. This can allowstructures to shift or sink or collapse.But most earthquakes are much shorter than therecent event in Japan, Ashford said. The length ofthe Japanese earthquake, as much as five minutes,may force researchers to reconsider the extent ofliquefaction damage possibly occurring insituations such as this.“With such a long-lasting earthquake, we sawhow structures that might have been okay after 30seconds just continued to sink and tilt as theshaking continued for several more minutes,” hesaid. “And it was clear that younger sediments, andespecially areas built on recently filled ground, aremuch more vulnerable.”The data provided by analyzing the Japaneseearthquake, researchers said, should make itpossible to improve the understanding of this soilphenomenon and better prepare for it in the future.Ashford said it was critical for the team to collectthe information quickly,before damage wasremoved in the recovery efforts.There’s no doubt that we’ll learn things from whathappened in Japan that will help us to reduce risksin other similar events,” Ashford said. “Futureconstruction in some places may make more use oftechniques known to reduce liquefaction, such asbetter compaction to make soils dense, or use ofreinforcing stone columns.”Ashford pointed out that northern California haveyounger soils vulnerable to liquefaction –on thecoast, near river deposits or in areas with filledground. The “young” sediments, in geologic terms,may be those deposited within the past 10,000years or more. In Oregon, for instance, thatdescribes much of downtown Portland, thePortland International Airport and other cities.Anything near a river and old flood plains is asuspect, and the Oregon Department ofTransportation has already concluded that 1100bridges in the state are at risk from an earthquake.Fewer than 15 percent of them have beenreinforced to prevent collapse. Japan has sufferedtremendous losses in the March 11 earthquake, butJapanese construction standards helped preventmany buildings from collapse – even as they tiltedand sank into the ground.Batteries Built by Viruses病毒电池What do chicken pox, the common coldM水痘、普通感冒、流感和艾滋病有哪些相似之处呢？这些都是由病毒引起的疾病。