“People were dying and we didn’t know why,” Cornman told me. “We didn’t understand the physics of why the planes were crashing.” The deadly gusts were thought to be blowing in from the ocean or from thunderstorms outside the airports. But the danger turned out to be right above them. In the late seventies, researchers at NCAR and the University of Chicago discovered that the crashes were caused by microbursts—sudden, violent downdrafts. In a microburst, a storm cloud dumps cool air and rain straight down, like water from a broken awning. The air spreads horizontally after it lands, so the pilot thinks he’s flying into a headwind at first. He lifts the plane’s nose slightly and decreases the engines’ thrust. Then the downdraft hits, followed by a vicious tailwind, sending the aircraft to the ground.
Венесуэла подписала новые контракты на поставку нефти США08:58
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“东鹏的高净利来自能量饮料为主的高毛利产品结构，且其分销销售费用率与管理研发费用率也相对更低。”饮料行业营销管理资深人士赵涛告诉南方周末记者，综合型公司品类更多、组织和渠道体系更重，通常对应更高的分销、促销和终端维护成本，以及更复杂的管理开支结构。，这一点在51吃瓜中也有详细论述
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