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After years of heated debate, gray wolves were reintroduced to Yellowstone National Park. Fourteen wolves were caught in Canada and transported to the park. By last year, the Yellowstone wolf population had grown to more than 170 wolves.
Gray wolves once were seen here and there in the Yellowstone area and much of the continental United States, but they were gradually displaced by human development. By the 1920s, wolves had practically disappeared from the Yellowstone area. They went farther north into the deep forests of Canada, where there were fewer humans around.
The disappearance of the wolves had many unexpected results. Deer and elk populations — major food sources (来源) for the wolf – grew rapidly. These animals consumed large amounts of vegetation (植被), which reduced plant diversity in the park. In the absence of wolves, coyote populations also grew quickly. The coyotes killed a large percentage of the park' s red foxes, and completely drove away the park' s beavers.
As early as 1966,biologists asked the government to consider reintroducing wolves to Yellowstone Park.They hoped that wolves would be able to control the elk and coyote problems.Many farmers opposed the plan because they feared that wolves would kill their farm animals or pets.
The government spent nearly 30 years coming up with a plan to reintroduce the wolves. The U.S.Fish and Wildlife Service carefully monitors and manages the wolf packs in Yellowstone. Today, the debate continues over how well the gray wolf is fitting in at Yellowstone. Elk,deer,and coyote populations are down,while beavers and red foxes have made a comeback.The Yellowstone wolf project has been a valuable experiment to help biologists decide whether to reintroduce wolves to other parts of the country as well.
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The Intelligent Transport team at Newcastle University have turned an electric car into a mobile laboratory named “DriveLAB” in order to understand the challenges faced by older drivers and to discover where the key stress points are.
Research shows that giving up driving is one of the key reasons for a fall in health and well-being among older people, leading to them becoming more isolated(隔绝) and inactive.
Led by Professor Phil Blythe, the Newcastle team are developing in-vehicle technologies for older drivers which they hope could help them to continue driving into later life.
These include custom-made navigation(导航) tools, night vision systems and intelligent speed adaptations. Phil Blythe explains: “For many older people, particularly those living alone or in the country, driving is important for preserving their independence, giving them the freedom to get out and about without having to rely on others.”
“But we all have to accept that as we get older our reactions slow down and this often results in people avoiding any potentially challenging driving conditions and losing confidence in their driving skills. The result is that people stop driving before they really need to.”
Dr Amy Guo, the leading researcher on the older driver study, explains, “The DriveLAB is helping us to understand what the key points and difficulties are for older drivers and how we might use technology to address these problems. “For example, most of us would expect older drivers always go slower than everyone else but surprisingly, we found that in 30mph zones they struggled to keep at a constant speed and so were more likely to break the speed limit and be at risk of getting fined. We're looking at the benefits of systems which control their speed as a way of preventing that.
“We hope that our work will help with technological solutions(解决方案) to ensure that older drivers stay safer behind the wheel.”
