首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Listening out for whale song is one way that ships can avoid colliding with whales. But what do you do if the whales aren’t sing
Listening out for whale song is one way that ships can avoid colliding with whales. But what do you do if the whales aren’t sing
admin
2013-01-15
27
问题
Listening out for whale song is one way that ships can avoid colliding with whales. But what do you do if the whales aren’t singing? One answer, developed by researchers in the Canary Islands, is to focus on the way the giant creatures mask the clamour of ocean noise.
No one knows how many whales are killed by ships each year, but collisions are thought to ac- count for up to a third of unnatural deaths. For the northern right whale, this means one or two individuals every year, and with only 300 animals left, that’s an unacceptable loss. There are three global hot spots for whale collisions: northern right whales are at risk in the Atlantic off the east coast of the US and Canada, fin whales in the Mediterranean, and sperm whales off the Canary Islands.
Last year, the Massachusetts-based international Fund for Animal Welfare attached hydro- phones to buoys and successfully listened out for right whale song in the North Atlantic. But since right whales remain silent for hours at a time, and sperm whales are silent for around haft the time, a better tracking technology is needed.
The new Whale Anti-Collision System (WACS), developed by Michel Andre, is designed to help ships in these hot spots steer clear of the whales. It uses a sonar technique called ambient noise imaging to locate the animals even when they are silent.
To do this, Andre has been testing a long lines of buoys, each bristling with 32 sensitive under- water microphones, or hydrophones, that pick up sea sounds such as breaking waves, rain and ship- ping noise. Any approaching whale blocks this background noise and creates a detectable "sound shadow".
By comparing the reflections received from the hydrophones on different buoys, Andre’s system can gather enough information to work out the whale’ s position and how fast it is moving. Software displays the results, on a 3D colour map. Underwater objects stand out like hot spots on a thermal image. In trials planned for next year, Andre will place two lines of 12 spherical buoys along the 120-kilometre ferry route between the islands of Tenerife and Gran Canaria. The signals will be sent to a land station where they will be analysed to create a 3D picture of the sea in real time.
If the trials are successful, the WACS software could be installed aboard ferries so that ships’ masters can steer clear of whales. Failing that, the whales’ movements could be tracked from shore- based installation and radioed to ships in the area.
The loss of one or two northern fight whales every year is considered an unaeeeptable loss because they ______.
选项
A、are the only Whales that can sing songs
B、are the only whales capable of masking the clamour of ocean noise
C、provide clues to scientists to study sea currents and waves
D、are on the very verge of distinction
答案
D
解析
从文中第二段可知with only 300 animals (northern right whales) left,如果每年减少一两头,该鲸群不久就会灭绝,选项D正确。
转载请注明原文地址:https://jikaoti.com/ti/8H8YFFFM
0
考博英语
相关试题推荐
StandardEnglishisthevarietyofEnglishwhichisusuallyusedinprintandwinchisnormallytaughtinschoolsandtonon-nat
Thefirstbig-namehackersincludeSteveWozniak,BillGatesandLinusTorvalds,allnowhighlyrecognisablenamesbehindmanyo
ProfessorTaylor’stalkhasindicatedthatsciencehasaverystrongontheeverydaylifeofnon-scientistsaswellasscientist
Partsofthehard-workingWisconsinRiver______;itsfishhaveasulphurousodor.
______enoughtimeandmoney,theresearcherswouldhavebeenabletodiscovermoreinthisfield.
Tomanypeople,ahusbandandwifealonedonotseemaproperfamily--theyneedchildrentoenrichthecircle,to______family
Ifyousmokeandyoustilldon’tbelievethatthere’sadefinitebetweensmokingandbronchialtroubles,heartdiseaseandlung
InthefirstyearorsoofWebbusiness,mostoftheactionhasrevolvedaroundeffortstotaptheconsumermarket.Morerecentl
(66)Applicationfilesarepiledhighlythismonthincollegesacrossthecountry.(67)Admissionsofficersareporingessaysan
Atfirst,thecompanyrefusedtopurchasetheequipment,butthisdecisionwas______revised.
随机试题
妇女有嚼槟榔习俗的民族是()。
患儿为40周足月儿,顺产,生后半小时即出现呕血。除考虑新生儿出血症外,还有可能是
下面属于操作风险的表现形式的有()。
下列企业出口应税消费品享受出口免税但不退税政策的有()。
心理过程包括()。
注意事项1.本题本由给定资料与作答要求两部分构成。考试时限为150分钟。其中,阅读给定资料参考时限为40分钟,作答参考时限为110分钟。满分为100分。2.监考人员宣布考试开始时,你才可以开始答题。3.请在题本、答题卡指定位置填写自己的姓名,填涂准考
2013年11月18日国家主席习近平在会见美国前总统克林顿时指出,中美两国正共同致力于中美“新型大国关系”。下列对于中美两国关系发展历程中的历史事件,时间排序正确的是()。①签订《中美贸易关系协定》②尼克松访华③中美联合发表“八一七公报”④
时务学堂
Theoldfarmerwasrundownbyacar.Hewastakentothehospitaland______onbythechiefsurgeonrightnow.
Taiwan’sdivorceratehascontinuedtoriseoverthepast10yearsasmoreandmoremarriedcouplehavegivenupontheir【B1】___
最新回复
(
0
)