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Climate Change Poses Major Risks for Unprepared Cities(气候变化给不备城市带来重大风险)A new examination of urban policies has beencarried out recently by Patricia Romero LankaoShe is a sociologist specializing in climate change and urbandevelopmentShe warns thatmany of the worlds fast-growing urban areas，especially in developing countrieswill likely sufferfrom the impacts of changing climateHer work also concludes that most cities are failing to reduce emissions of carbon dioxide and other greenhouse gasesThese gases are knownto 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 majorsources of greenhouse gasesAnd urban populations are likely to be among those most severely affected by future climate change. Lankaos findingshighlight ways in which city-residents are particularly vulnerable, and suggest policy interventions that could offer immediate and longer-term benefitsThe 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 andprolonged hot weather. Storm surges can flood coastal areas and prolonged hot weather can heat heavily paved cities more than surrounding areasThe impacts of such natural events can be more serious in an urban environmentFor example，a prolonged heat wave can increase existinglevels of air pollution，causingwidespread health problemsPoorer neighborhoods thatmay lack basic facilities such as drinking water or a dependable network of roads，are especially vulnerable to natural disastersMany residents in poorer countries live in substandard housing withoutaccess 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 thanmeaningful responses,Romero Lankao writes, ” They dont impose construction standards that could reduce heating and air conditioning needs. They dont emphasize mass transit and reduce automobileuse. In fact, many localgovernmentsare takinga handsoffapproach.” Thus, she urges them tochangetheir 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（快餐加免费降胆固醇药物可以降低罹患心脏病的风险）Fast food outlets could provide statin drugs free of chargeso that customers can reduce the heart disease dangers of fatty food, researchers at Imperial College London suggestina new studyStatins reduce the amountof unhealthy ”LDL” cholesterol in the blood. A wealth of trialdata has proven them to be highly effective at lowering a persons heart attack risk.In a paper published in theAmerican Journal of Cardiology，Dr Darrel Francis and colleagues calculate that the reduction in heart attack risk offered by a statin is enoughto offset the increase in heart attack risk from eatingacheeseburger and drinking a milkshakeDr Francis，from the National Heart and Lung Institute at Imperial College London，who is the senior author of the study, said:”Statins dont cut out a11 of the unhealthy effects of cheeseburgers and French friesIts better to avoid fatty food altogetherBut weve worked out that in terms of your possobilityof having a heart attack. Taking a statin can reduce your risk to more or less the same degree as a fast food meal increases it.”“Its ironic that people are free to take as many unhealthv condiments in fast food outlets asthey like, but statins, which are beneficial to heart health, have to be prescribed. It makessense to make risk-reducing statins available just as easily as the unhealthy condiments that are provided free of chargeIt would cost less than 5 pence per customer -not much different to a sachet of sugar.” Dr Francis saidWhen people engage in risky behaviours like driving or smoking,theyre encouraged to take measuresthat lower their risk, 1ike wearinga seatbelt or choosing cigarettes with filters. Taking a statin is a rational way of lowering some of the risks of eating a fatty mealBetter Solar Energy Systems: More Heat, More Light（更有效的太阳能系统：更多能量，更强灯光）Solar photovoltaic thermal energy systems, or PVTs, generate both heat and electricity, but until now they havent been very good at the heat-generating part compared to a stand-alone solar thermal collector. Thats because they operate at low temperatures to cool crystalline silicon solar cells, which lets the silicon generate more electricity but isnt a very efficient way to gather heat. Thats 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 its 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 Queens University, 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 dont 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. “That means that their efficiency drops when you expose them to light pretty much the worst possible effect for a solar cell,” Pearce explains，which is one of the reasons thin- film solar panels make up only a small fraction of the market. However, Pearce and his team found a way to engineer around the Staebler-Wronski effect by incorporating thin-film silicon in a new type of PVT. You dont have to cool down thin-film silicon to make it work. In fact，Pearces group discovered that by heating it to solar-thermal operating temperatures，near the boiling point of water, they could make thicker cells that largely overcame the Staebler-Wronski effect. When they applied the thin-film silicon directly to a solar thermal energy collector , they also found that by baking the cell once a day，they boosted the solar cells electrical efficiency by over 10 percent. Sharks Perform a Service for Earths Waters（鲨鱼有益于地球水系） It is hard to get people to think of sharks as anything but a deadly enemy. They are thought to attack people frequently. But these fish perform a valuable service for earths waters and for human beings. Yet business and sport fishing are threatening their existence.Some sharks are at risk of disappearing from earth. Warm weather may influence both fish and shark activity. Many fish swim near coastal areas because of their warm waters. Experts say sharks may follow the fish into the same areas,where people also swim. In fact, most sharks do not purposely charge at or bite humans. They are thought to mistake a person for a sea animal, such as a seal or sea lion. That is why people should not swim in the ocean when the sun goes down or comes up. Those are the times when sharks are looking for food. Experts also say that bright colors and shiny jewelry may cause sharks to attack. A shark has an extremely good sense of smell. It can find small amounts of substances in water, such as blood, body liquids and chemicals produced by animals. These powerful senses help sharks find their food. Sharks eat fish, any other sharks, and plants that live in the ocean. Medical researchers want to learn more about the sharks body defense, and immune systems against disease. Researchers know that sharks recover quickly from injuries. They study the shark in hopes of finding a way to fight human disease. Sharks are important for the worlds oceans. They eat injured and diseased fish. Their hunting activities mean that the numbers of other fish in ocean waters do not become too great. This protects the plants and other forms of life that exist in the oceans.Liquefaction” Key to Much of Japanese Earthquake Damage（液化是日本地震破坏的关键）The massive subduction zone earthquake in Japan caused a significant level of soilliquefaction that has surprised researchers with its widespread severity, a new analysis shows.Weve seen localized examples of soil liquefaction as extreme as this before, but the distance and extent of damage in Japan were unusually severe, said Scott Ashford, a professor of geotechnical engineering at Oregon State University.Entire structures were tilted and sinking into the sediments, Ashford said. The shifts in soil destroyed water, drain and gas pipelines, crippling the utilities and infrastructure these communities need to function. We saw some places that sank as much as four feet.Some degree of soil liquefaction is common in almost any major earthquake. Its a phenomenon in which soils soaked with water, particularly recent sediments or sand, can lose much of their strength and flow during an earthquake. This can allow structures to shift or sink or collapse. But most earthquakes are much shorter than the recent event in Japan, Ashford said. The length of the Japanese earthquake, as much as five minutes, may force researchers to reconsider the extent of liquefaction damage possibly occurring in situations such as this.With such a long-lasting earthquake, we saw how structures that might have been okay after 30 seconds just continued to sink and tilt as the shaking continued for several more minutes, he said. And it was clear that younger sediments, and especially areas built on recently filled ground, are much more vulnerable.The data provided by analyzing the Japanese earthquake, researchers said, should make it possible to improve the understanding of this soil phenomenon and better prepare for it in the future. Ashford said it was critical for the team to collect the information quickly,before damage was removed in the recovery efforts.Theres no doubt that well learn things from what happened in Japan that will help us to reduce risks in other similar events, Ashford said. Future construction in some places may make more use of techniques known to reduce liquefaction, such as better compaction to make soils dense, or use of reinforcing stone columns.Ashford pointed out that northern California have younger soils vulnerable to liquefaction -on the coast, near river deposits or in areas with filled ground. The young sediments, in geologic terms, may be those deposited within the past 10,000 years or more. In Oregon, for instance, that describes much of downtown Portland, the Portland International Airport and other cities.Anything near a river and old flood plains is a suspect, and the Oregon Department of Transportation has already concluded that 1,100 bridges in the state are at risk from an earthquake. Fewer than 15 percent of them have been reinforced to prevent collapse. Japan has suffered tremendous losses in the March 11 earthquake, but Japanese construction standards helped prevent many buildings from collapse-even as they tilted and sank into the ground.
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