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World Crude Oil Production May Peak Decade Earlier Than Some Predict In a finding that may speed efforts to conserve oil, scientists in Kuwait predict that world conventional crude oil production will peak in 2014. This prediction is almost a decade earlier than some other predictions. Their study is in ACS’ Energy & Fuels. lbrahim Nashawi and colleagues point out that rapid growth in global oil consumption has sparked a growing interest in predicting "peak oil". "Peak oil" is the point where oil production reaches a maximum and then declines. Scientists have developed several models to forecast this point, and some put the date at 2020 or later. One of the most famous forecast models is called the Hubbert model. It assumes that global oil production will follow a bell shaped curve. A related concept is that of "Peak Oil". The term "Peak Oil" indicates the moment in which world wide production will peak, afterwards to start on irreversible decline. The Hubbert model accurately predicted that oil production would peak in the United States in 1970. The model has since gained in popularity and has been used to forecast oil production worldwide. However, recent studies show that the model is insufficient to account for more complex oil production cycles of some countries. Those cycles can be heavily influenced by technology changes, politics, and other factors, the scientists say. The new study describes development of a new version of the Hubbert model that provides a more realistic and accurate oil production forecast. Using the new model, the scientists evaluated the oil production trends of 47 major oil-producing countries which supply most of the world’s conventional crude oil. They estimated that worldwide conventional crude oil production will peak in 2014, years earlier than anticipated. The scientists also showed that the world’s oil reserves are being reduced at a rate of 2.1 percent a year. The new model could help inform energy-related decisions and public policy debate, they suggest. The term a bell shaped curve, appearing in paragraph 2 indicates that global oil production will______.
Sharks Perform a Service for Earth’s Waters It is hard to get people to think of sharks as anything but a deadly enemy. They are thought to (51) people frequently. But these fish perform a (52) service for earth’s waters and for human beings. Yet business and sport fishing are threatening their (53) . Some sharks are at risk of disappearing from (54) . Warm weather may influence both fish and shark activity. Many fish swim near coastal areas (55) their warm waters. Experts say sharks may follow the fish into the same areas, (56) people also swim. In fact, most sharks do not purposely charge at or bite humans. They are thought to mistake a person (57) 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 (58) 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 (59) produced by animals. These powerful (60) help sharks fred their food. Sharks eat fish, any (61) sharks, and plants that live in the ocean. Medical researchers want to learn more about the shark’s body defense, and immune (62) against disease. Researchers know that sharks (63) quickly from injuries. They study the shark in hopes of finding a way to fight human disease. Sharks are important for the world’s (64) . They eat injured and diseased fish. Their hunting activities mean that the numbers of other fish in ocean waters do not become too (65) . This protects the plants and other forms of life that exist in the oceans.
A over the past 50 years B beneath the earth surface C by more than 50 percent D for more than four decades E as a raw material F for families When manufacturing many products, people commonly use natural gas______.
患者，女，12岁，发现左下腹部有一肿物入院。肛查肿物如手拳大小，囊实性，B超检查少量腹水。 本例的预后，估计5年生存率为
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