字神帝國英語天地

 
 今日主題：Eavesdrop on Echolocation to Count Bats  竊聽蝙蝠回升定位

 洪欣老師推薦：托福聽力最好的課外教材：60-Second Science
 康康精選托福會考的主題，堅持每天精聽一定會進步的哦!!

 建議方法：
1. 先聽兩三遍 (不看文稿)
2. 再一句一句聽寫 (每句都要聽寫數遍，直到寫出85%以上的字)
3. 最後check文稿，看哪聽不出來，單字沒背過，還是發音不熟。
4. 堅持天天聽，就能每天進步哦。

 MP3音檔 (按右鍵可下載聽)：喜歡的同學，幫忙推或按讚哦~~
http://online1.tingclass.net/voaspe/…/20160413sa_science.mp3

 只有音檔怎夠，聽不懂地方，不用怕，康康幫你準備好中英文稿了：

 中英文稿：
"What you're listening to is what I like to call the beautiful chaos of the bat echolocation stream." Laura Kloepper, a bioacoustician at Saint Mary's College in Indiana. "So you're listening to the sound of probably a couple hundred bats emerging per second from the cave and there's a microphone that we have suspended in the middle of the bats to record the sounds. These are the echolocation sounds the bats make when they're flying and this is what they use to help navigate and find prey."
你所聽到的是我稱之為天籟之音的蝙蝠回聲定位流。蘿拉`科柏是印第安那州聖瑪麗學院的生物聲學家。“你聽到的是每秒鐘從洞穴中出來的數百隻蝙蝠發出的聲 音，我們在蝙蝠當中安裝了一個麥克風，來記錄這些聲音。這是蝙蝠在飛行中發出的回升定位流，蝙蝠利用回聲定位幫助自己進行導航和尋找獵物。”

The sounds—slowed down 10 times so we can hear them—were recorded at a network of lava tube caves in New Mexico. Kloepper and her colleagues camped out there to study how Mexican free-tailed bats echolocate in huge swarms without jamming each other's signals. And they noticed that the intensity of the “bleeps” seemed to correlate with the number of bats fluttering out of the cave. Meaning, maybe you could survey their populations with audio. "One night we were sitting around the campfire at our field site and we said, I wonder if this would actually work?"
這些聲音——經過10倍減慢處理，我們人類才能夠聽到——是在新墨西哥州的很多熔岩洞中記錄的。科柏和同事們在熔岩洞外露營來研究是蝙蝠是通過何種方式在 大群蝙蝠中不干擾同伴的信號的情況下，進行聲波定位。他們注意到聲波的強度和飛出洞穴的蝙蝠的數量有關。這也就意味著，也許可以利用聲音來計算蝙蝠的數 量。“有一天晚上，我們圍著篝火聊天，我猜想，這個辦法可行嗎?”

So they set up a new experiment, capturing audio and GoPro video at the cave site. They counted the bats in each video frame, and correlated that to the zips and zaps, to create predictive models. They then tried the method at another cave—and found that their models could indeed estimate the number of bats emerging using acoustics alone. The study is in the journal Royal Society Open Science.
所以，他們制定了新的實驗計畫，在洞穴處捕捉音訊和視頻。他們計算了每個視頻幀數中的蝙蝠數量，並將此與聲波相關聯創建了預測模型。然後，他們將這種方法 應用於其他洞穴——結果表明，這些模型利用聲學可以估計出現的蝙蝠數量。該研究結果發表在英國皇家協會《Royal Society Open Science》。

"Historically what has been used to estimate bats has been photographic estimates, visual estimates, mark-recapture estimates, and those have been highly prone to bias." Newer technology, like thermal imaging cameras is accurate, but expensive. So at a time of epic bat mortality—due to, for example, the fungal white nose syndrome that’s wiping out bats in Canada and the U.S.—Kloepper says her method might be a cheap, reliable way to determine the most critical caves to save.
“過去人們利用照片、視覺、標記捕捉方法來估計蝙蝠的數量，但是這些方法都存在著很大的誤差。”熱成像相機等先進的技術測量的很準確，但價格昂貴。所以， 蝙蝠大量死亡時，如真菌白鼻綜合症肆虐了加拿大和美國的蝙蝠，科柏表示，自己的方法將會是決定拯救最重要洞穴的最低廉、可行的辦法。