60secondscience60秒科学听力原文5.docx

1、60secondscience60秒科学听力原文5Thieving Bird Apes Its Victims The fork-tailed drongo can mimic the alarm calls of dozens of other species of animals, including nonbirds, to drive them off and steal their food. Cynthia Graber reportsMay 5, 2014 |By Cynthia Graber Music plays Neil Young? No, thats Jimmy Fal

2、lon imitating Neil Young. Doing impressions can be a valuable skill. In fact, a bird called the fork-tailed drongo makes a good living at it, in its home in Africas Kalahari Desert. The drongo can mimic the alarm calls of another bird. When that bird flees the imagined danger, the drongo swoops in t

3、o take any food left behind.An animal mimicking another animal is not rare. And targets can grow wise to the trick. The drongos real talent is that it can do the warning calls of multiple species. Music plays Like how Jimmy Fallon can also do Van Morrison.Researchers followed 64 wild drongos for nea

4、rly 850 hours. Drongos do sound accurate alarms in response to actual predators. But when they spot a tempting meal in another birds possession, they send out a false alarm. Heres one mimicking a pied babbler. Drongo callAnother a glossy starlings alarm. Drongo callAnd heres a drongo mimicking a mee

5、rkat alarm. Drongo callThe researchers saw almost 700 drongo attempts to steal food. They estimate that any one drongo might know up to 32 different species alarms. And stolen food accounted for nearly a quarter of their daily intake. The study is in the journal Science. Tom P. Flower, Matthew Gribb

6、le and Amanda R. Ridley, Deception by Flexible Alarm Mimicry in an African BirdFool birds once? Shame on them. Fool birds multiple times? Success for the fork-tailed drongo.Cynthia GraberThe above text is a transcript of this podcast.Surgeons Try Cold Cutting for Critically Injured A clinical trial

7、tests whether induced hypothermia can allow surgeons to save critically wounded patients who would not survive surgery at normal temperatures. Erika Beras reportsMay 6, 2014 |By Erika Beras On rare occasions, a swimmer can survive a near-drowning because cold water has protected their brainseven if

8、they were submerged for up to an hour. Now a clinical trial is testing whether extreme cold can save critically injured gunshot and knife wound patients.Its called the Emergency Preservation and Resuscitation for Cardiac Arrest from Trauma Study. Lead Surgeon Sam Tisherman at the University of Pitts

9、burgh Medical Center explains that patients are not declared dead, but:“Theyd be close. Theyre in cardiac arrest and certainly if we cant get a pulse back theyd be dead. But were not waiting to the point where the surgeons would declare them dead. Were trying to do this right before this, and find t

10、he best window of opportunity where our standard of care hasnt worked but its not too late to try something new.”Surgeons will cool the patients bodies to 50 degrees by pumping dozens of liters of cold saline into the heart. This induced hypothermia nearly halts all activity in the body and brain.By

11、 freezing patients, the surgeons will also freeze timegiving them the opportunity to repair wounds a warm patient wouldnt typically survive. Should the procedure prove effective, it could give a new meaning to the phrase “cold comfort.”Erika BerasThe above text is a transcript of this podcast.Lasers

12、 ID Insects by Wing Beats Using laser sensing of insect wing beats, plus location and time of day, researchers report 99 percent accuracy identifying individuals in a group of six insect species. A future surveillance system would be of interest to farmers and insect-borne disease monitors. Cynthia

13、Graber reportsMay 7, 2014 |By Cynthia Graber To a farmer, good insects pollinate. And bad insects decimate. And theyve often had a tough time knowing which flying creatures were invading their crops. Now eavesdropping researchers might offer help.For 60 years, scientists have tried to identify insec

14、ts by their wing sounds. The challenge increases with distance, wind and other noises. So researchers created a monitor using lasers. When an insect crosses the laser, the shadow of the wing beats gets recorded and translated into an mp3. Heres a female aedes aegypti mosquito. Heres a female culex q

15、uinque fasciatus.The researchers spent three years gathering data from dozens of sensors. They have tens of millions of data pointsmore than had been previously collected all togetherfor their algorithms. Using wing beats plus location and time of day, theyve achieved up to 99 percent accuracy ident

16、ifying six insect species thus far.The research will be published in the Journal of Insect Behavior. Yanping Chen, Eamonn Keogh et al, Flying Insect Classification With Inexpensive SensorsThe prototype was made of LEGOs, a 99-cent laser pointer and part of a TV remote. So researchers say a setup cou

17、ld be manufactured for less than $10. It could identify both farm pests and disease carriers. Which could help people picnic in peace.Cynthia GraberThe above text is a transcript of this podcast.Oenophiles Confirm Fruity Flavors Finish First Wine researchers find that fruity flavors tend to finish q

18、uickest on the palate, whereas oaky flavors linger longer-as aficionados have long claimed. Christopher Intagliata reportsMay 12, 2014 |By Christopher Intagliata The lore among wine aficionados is that fruity flavors tend to finish quickest on the palate, whereas oaky flavors linger longer.“And then

19、 when you go to the scientific literature, you find out that really there havent been scientific studies done on it.” Carolyn Ross, a sensory scientist at Washington State University.She and her colleagues investigated the claims. They identified four flavor compounds common in white wine, which giv

20、e floral, fruity, mushroomy and oaky notes. They then studied the compounds in whats known as a model wine: “Meaning that it had alcohol in it, it had some sugar, some acid in it, but it wasnt actually wine.”They added the compounds one at a time to their model wine, and asked trained tasters to clo

21、ck how long it took flavors to fade. Fruity did indeed finish firstlasting a minute and a half. The others took 30 seconds longer to fade. And even when mixed with the other flavors, fruity still finished firstso the lore was right.The study appears in the journal Food Quality and Preference. Emily

22、S. Goodstein et al, Perception of flavor finish in model white wine: A time-intensity studyAs for home tasters? “Pay attention to the finish, perhaps time it, if thats your thing.” It does happen to be ours.Christopher IntagliataThe above text is a transcript of this podcast.Healthy Lung Microbes Ke

23、ep Mice Breathing Easy Like humans, mice start life with sterile lungs that soon get colonized by microbes, which appear to protect the lung tissue from an asthmalike reaction in the presence of dust mites. Cynthia Graber reports May 14, 2014 |By Cynthia Graber Human cells are outnumbered ten-to-one

24、 by the microbes that thrive in and on us. Now a study finds that the tiny organisms living in our lungs may protect us from asthma.A newborns lungs start out sterile and then become colonized by microbes. To see how lung microbes might influence disease susceptibility, researchers studied mice, whi

25、ch also start with sterile lungs that soon host microbes.In the first two weeks of life, these microbial communities shift and proliferate. So the scientists looked at three groups of mice: babies three days old, 15-day-old mice, and two-month old adults. All were exposed to dust mites, which provok

26、e inflammation.The newborn mice developed inflamed lungssimilar to asthma. But the older groups remained mostly inflammation free, indicating a protective role for their lung microbes.The researchers then exposed older mice whose lungs had been kept sterile to mites. These mice did get inflamed lung

27、s. The study is in the journal Nature Medicine. Eva S. Gollwitzer et al, Lung microbiota promotes tolerance to allergens in neonates via PD-L1The researchers say that early lung colonization by a diverse, protective microbial community appears crucial. They hope to extend these studies to human infa

28、ntsto better understand our lung microbes, and help kids breathing freely. (Also see Drugs to Be Derived from Insights into Body-Dwelling Bacteria)Cynthia GraberThe above text is a transcript of this podcast.Scientific American is part of Nature Publishing Group.Twitter Opinion Quickly Stabilizes A

29、study of millions of tweets found that public opinion quickly solidifies, even without an overwhelming concensus. Allie Wilkinson reportsMay 15, 2014 |By Allie Wilkinson All rise, the Twitter court of public opinion is now in session.And the next case on the docket will reach a quick verdict. Becaus

30、e public opinion solidifies rapidly on Twitter. Thats according to a study in the journal Chaos. Fei Xiongand Yun Liu, Opinion formation on social media: An empirical approachResearchers collected almost 6 million tweets during a six-month period. They sorted the tweets for either positive or negati

31、ve sentiments, then focused on three topics related to electronics. At first opinions fluctuated, with one side gaining a slight advantage. This advantage grew gradually and then quickly leveled off, leaving one opinion in a stable and dominant positionbut without an overwhelming consensus.And once

32、public opinion is established, it is unlikely to change. Only those who see a large number of dissenting opinions among the people they follow on Twitter will reconsider and examine the opposing viewpoint.These results may offer a valuable lesson for companies, candidates and anyone else in the spotlight. If you plan to sway the jury, be sure to make your case early. Because once public opinion stabilizes, the jury i