疫情封城期间鸟类叫声更低
文章来源:未知 文章作者:enread 发布时间:2020-09-30 08:57 字体: [ ]  进入论坛
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San Francisco birds started singing differently in the quiet of the coronavirus lockdown, says a study in Science.
 
《科学》杂志的一项研究称,旧金山的鸟儿在安静的疫情封锁期间叫声发生了改变。
 
Before, urban white-crowned sparrow's breeding territories were almost three times as loud as rural territories, the study found.
 
But during the pandemic, researchers noted1 that noise levels in urban areas were drastically lower. In fact, they were consistent with traffic flow in the mid-1950s.
 
"In other words, the Covid-19 shutdown created a silent spring across the SF Bay Area," researchers noted.
 
By analyzing2 traffic flow data from the Golden Gate Bridge, researchers found that vehicle crossings from April to May 2020 returned to levels not seen since 1954. While noise recordings3 are not available from the 1950s, researchers said this indicates that a brief but dramatic change in human behavior effectively erased4 more than a half-century of urban noise pollution.
 
Birds responded by producing higher performance songs at lower amplitudes5, maximizing communication distance and salience.
 
"We found that birds sang more softly when noise levels were lower," researchers said in the study.
 
Even though the birds were singing more softly, the study found that communication distance nearly doubled, elevating species fitness and increasing mating potential.
 
"In addition, the signal-to-noise ratio doubled, which helps explain media reports suggesting that bird songs sounded louder during the shutdown," the researchers said.


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1 noted 5n4zXc     
adj.著名的,知名的
参考例句:
  • The local hotel is noted for its good table.当地的那家酒店以餐食精美而著称。
  • Jim is noted for arriving late for work.吉姆上班迟到出了名。
2 analyzing be408cc8d92ec310bb6260bc127c162b     
v.分析;分析( analyze的现在分词 );分解;解释;对…进行心理分析n.分析
参考例句:
  • Analyzing the date of some socialist countries presents even greater problem s. 分析某些社会主义国家的统计数据,暴露出的问题甚至更大。 来自辞典例句
  • He undoubtedly was not far off the mark in analyzing its predictions. 当然,他对其预测所作的分析倒也八九不离十。 来自辞典例句
3 recordings 22f9946cd05973582e73e4e3c0239bb7     
n.记录( recording的名词复数 );录音;录像;唱片
参考例句:
  • a boxed set of original recordings 一套盒装原声录音带
  • old jazz recordings reissued on CD 以激光唱片重新发行的老爵士乐
4 erased f4adee3fff79c6ddad5b2e45f730006a     
v.擦掉( erase的过去式和过去分词 );抹去;清除
参考例句:
  • He erased the wrong answer and wrote in the right one. 他擦去了错误答案,写上了正确答案。 来自《简明英汉词典》
  • He removed the dogmatism from politics; he erased the party line. 他根除了政治中的教条主义,消除了政党界限。 来自《简明英汉词典》
5 amplitudes 4e409a57adec323b4e77d839218c2fae     
振幅( amplitude的名词复数 ); 广大; (智力的)幅度; 充足
参考例句:
  • As with incoherent light one then adds irradiances rather than amplitudes. 就和非相干光的情况一样,这时是将辐照度相加而不是把振幅相加。
  • Unfortunately, it is not possible to disentangle these two amplitudes experimentally. 遗憾的是,实验上不可能分开这两个振幅。
TAG标签: traffic noise birds
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