问题
单项选择题
下列不是IMO/IHO所规定的ECDIS至少必须显示的信息是?()
A.水道测量数据
B.助航物标
C.潮流
D.规定的边界
答案
参考答案:C
下列不是IMO/IHO所规定的ECDIS至少必须显示的信息是?()
A.水道测量数据
B.助航物标
C.潮流
D.规定的边界
参考答案:C
Now Hear This What do former American president Bill Clinton and rock musician Pete Townshend have in common.'? Both men have hearing damage from exposure to loud music, and both now wear hearing aids as a consequence. As a teenager, Clinton played saxophone in a band. Townshend, who has the more severe hearing loss, was a guitarist for a band called the Who. He is one of the first rock musicians to call the public's attention to the problem of hearing loss from exposure to loud music. Temporary hearing loss can happen after only 15 minutes of listening to loud music. One early warning sign is when your ears begin to feel warm while you listen to music at a rock concert or through headphones. One later is that an unusual sound or a ringing is sometimes produced in your head after the concert. "What happens is that the hair cells in the inner ear are damaged, but they're not dead," says physician and ear specialist Dr. Sam Levine. According to Dr. Levine, if you avoid further exposure to loud noise, it's possible to recondition the cells somewhat. However, he adds, "Eventually, over a long period of time, hair cells are permanently damaged." And this is no small problem. What sound level is dangerous? According to Dr. Levine, regular exposure to noise above 85 decibels (分贝) is considered dangerous. The chart below offers a comparison of decibel levels to certain sounds. Here's another measurement you can use. If you're at a rock concert and the music is so loud that you have to shout to make yourself heard, you' re at risk for hearing loss. That's when wearing protective devices such as earplugs becomes critical. The facts are pretty frightening. But are rock bands turning down the volume.'? Most aren't. "Rock music is supposed to be loud," says drummer Andrew Sather. "I wouldn't have it any other way. And neither would the real fans of rock. " Continued exposure to loud music and the failure to wear earplugs can lead to deafness, according to Dr. Levine. He states, "There's no cure for hearing loss. Your ears are trying to tell you something. That ringing is the scream of your hair cells dying. Each time that happens, more and more damage is done. "
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