【Native Speaker每日综合训练—36系列】【36-05】科技

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大家好!胖胖翔来了! 希望今天能够激发大家的好奇心！一种罕见的独角鲸，你能相信它的角实际上是牙齿吗？亚裔的学生在美国academic achievement 领先于其他学生，美国国家科学院给的理由究竟有多简单，你猜？阿富汗那可怜的人儿，被山崩夺取了多少性命！尽在今日科技，stay with us! Enjoy~

Part I：Speaker

Article 1
Thieving 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 reports


[Music plays] Neil Young? No, that’s Jimmy Fallon 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 Africa’s Kalahari Desert. The drongo can mimic the alarm calls of another bird. When that bird flees the imagined danger, the drongo swoops in to take any food left behind.

An animal mimicking another animal is not rare. And targets can grow wise to the trick. The drongo’s 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 nearly 850 hours. Drongos do sound accurate alarms in response to actual predators. But when they spot a tempting meal in another bird’s possession, they send out a false alarm. Here’s one mimicking a pied babbler. [Drongo call]

Another a glossy starling’s alarm. [Drongo call]

And here’s a drongo mimicking a meerkat alarm. [Drongo call]

The 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 Gribble and Amanda R. Ridley, Deception by Flexible Alarm Mimicry in an African Bird]

Fool birds once? Shame on them. Fool birds multiple times? Success for the fork-tailed drongo.

—Cynthia Graber


Source:
http://www.scientificamerican.com/podcast/episode/thieving-mimic-bird/
【Rephrase1】

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Part III： Obstacle

【Paraphase7】
Article 6
Why some animals eat their young

Stacey Tabellario and Mindy Babitz are like many new mothers. They are with the baby every second she’s awake. They watch her on a monitor while she sleeps. They prepare bottles, talk to her and carry her and get little sleep themselves.

But the baby is a sloth bear (think Baloo from “The Jungle Book”), the only one of its kind born in captivity in the United States this year. And she is in Tabellario and Babitz’s care for a reason that’s simple and hard to dispute: when she was born, her mother ate her siblings.

“Now we’re mom,” said Tabellario one of the six zookeepers caring for the cub. “It’s an amazing experience, and we’re learning a lot, but there is still that bittersweet tone to it, because we all know that the first choice for any animal is to be raised by their mother.”

At first, zookeepers were thrilled when Khali, named for the Hindu goddess of destruction from the bears’ native India, gave birth to three cubs, an unusually large litter for a sloth bear.

But the first was stillborn. She consumed that cub immediately. A week later, she ate the second and began neglecting the third.

Tabellario says Khali’s reaction was normal, even healthy for a mother bear.

“It sounds very shocking, but it’s not something that shocks us as keepers. That’s the natural history of carnivores.”

It sounds counterintuitive to evolution, but infanticide in the wild is well-documented, said Doug Mock, professor of biology at the University of Oklahoma and author of a book on the subject. Animal parents have limited resources to dedicate to their offspring, he said, and if the baby is sick or weak, carnivores have been known to consume babies or abandon them. Cannibalism gives the mother the calories she needs to raise her healthy babies or get pregnant again.

That may have been the case for Khali, Tabellario said. A necropsy of her second cub revealed that the cub had a parasite in its intestines, which Khali may have sensed. When the keepers pulled the surviving cub from the den, she was ill too.

Sometimes it’s the mother or father that kills; sometimes it’s the siblings. Mock remembers watching a group of egret chicks peck their sibling to death, while their mother stood idly by, cleaning her feathers.

“It’s the most startling thing I’ve ever seen in the field,” he said. “I literally sat and watched and thought, ‘Any second, the parents will step in and stop this.’”

When asked him how he felt witnessing this behavior: “My soul died,” he said.

Mock has seen birds push their chicks from the nest, abandon them, even starve them. In the animal kingdom, he says, infanticide is not about pathology. It’s about ensuring that the strongest offspring survive.

“It’s one of the less pleasant aspects of nature, something humans don’t like to think about. You want to think of nature as warm, cuddly and fuzzy,” he said. “We assume that other species look at offspring the same way we look at offspring… To us it seems as if (infanticide) must be some sick kind of thing, but it isn’t necessarily.”

Infanticide can be accidental, too, said Susan Margulis, associate professor of biology at Canisius College.

“The thing that people don’t realize is that most young animals die. Most die when they’re in infancy. Animals mostly raise two babies to adulthood. It’s just more noticeable in zoos,” she said.

That’s because motherhood has a learning curve, she said, and it doesn’t come to all animals naturally the first time. She worked with primates in zoos, and found that new mothers must learn how to nurse their young, and how to properly care for them.

“I’ve seen primate mothers that were good enough, but not great. Sometimes good enough is okay,” she said. “That first breeding attempt is a learning experience. You almost have to assume it’s not going to go well. In evolution, that very well could have been the case for humans ancestors as well.” She added, “Even human mothers need to work out details of how to do this new job that they may not have any experience with.”

Zoos can’t always wait for mothers to figure it out. That was the case for Ally, a cheetah at the National Zoo. This winter she gave birth to a litter of four cubs. At first, keepers breathed a sigh of relief, said Copper Aitken-Palmer, chief veterinarian at the National Zoo. The new cheetah mom was nursing and grooming her cubs normally. But three weeks later, zookeepers noticed that Ally was carrying her cubs in and out of the den more than normal. The cubs became lethargic, but Ally continued to pace with them.
Adrienne Crosier, who manages the cheetah breeding program at the Smithsonian Conservation Biology Institute, says the keepers typically leave cubs with their mothers for as long as possible, but something was clearly wrong.

“She was carrying them because she was nervous and agitated, and we do see a lot of very nervous behavior in first-time cheetah moms,” she said. “It was kind of a difficult situation because every time we tried to treat them it made Ally more agitated, which then made her want to carry them more, which then exasperated the injuries.”

Ally had bitten down on the scruffs of their necks too roughly, causing deep wounds which had become infected, Aitken-Palmer said. She estimates the zoo had a few hours to save the cheetah cubs. On Christmas Day, keepers made the decision to take the cubs away from Ally.

“She went from a nervous mom to inadvertently doing mortal damage to these cubs,” Aitken-Palmer said. “We pretty quickly figured out that these cubs weren’t going back to their mom. And they may not make it at all. They were septic with very low glucose, which is blood sugar. The female actually came in seizuring, her blood sugar was so low. Frankly, I’ve not turned around a lot of neonates that were in that condition.”

One of the cubs died. The other three underwent three major surgeries each and hundreds of stitches over the following weeks. The cubs weren’t weaned, so they still needed milk and multiple feedings every day.

When animal mothers neglect or try to kill their own young in captivity, hand-rearing is one option, Margulis said, one that zoos utilize less than they did 30 years ago. Though in some cases, animal parents are so notoriously neglectful or the species is so rare, hand-raising becomes the first option.

At the Lincoln Park Zoo in Chicago, the Micronesian kingfisher, a rare bird with fewer than 130 individuals left in the world, is an “always-hand-raise” chick, said Dave Bernier, general curator for the zoo. Kingfishers, like many birds, are notoriously neglectful parents, he said, and the species is so endangered that each chick is valuable. But overall, as scientists have learned more about how animals behave in the wild, zoos have tried to minimize the amount of contact they have with young animals, and if they can, return them to their social groups.

“We did more hand-raising of animals in the past. At the time, it was a lack of understanding of the needs of the animals, which has changed. The time that the infant spends with their species is critical,” he said. “You might be providing all the nutrients but having the animal live with their group is more important, all the time.”

For the sloth bear cub, they do their best to recreate the care she would get from her mother. Early on, zookeepers wore the newborn cub in slings across their chests, because sloth bear mothers carry their newborns to keep the baby warm.

Feeding her was also a new challenge for the keepers. As a baby, she needed to be fed eight times a day. There are no sloth bear-specific formulas, so keepers mixed puppy formula and human formula for her bottles. The sloth bears’ refrigerator is stocked with mealworms, their favorite food, jams and fruits, which they started serving to the cub.
These bears may have Baloo’s laid-back attitude, but they are still dangerous, wild animals. She pointed to a jar of “emergency honey” on top of the refrigerator, which they save in the event of a bear escape. The emergency honey is thrown in one direction, while the keepers run in the other.

Now that the cub is two-and-a-half months old, she’s a toddler, and the keepers let her climb on them the way she would with her mother. Raising the cub is a new experience for all the keepers, so they’re constantly trying new methods for interacting with her, Tabellario said.

“We’re kind of just putting pieces together from other zoos, from books we’ve read about behavior, from what we know about natural history,” she said. “There is not a lot of information out there, so a lot of it is us learning as we are going, but so far we are on a good path. So far she’s a very confident bear. We have high hopes for her.”

The challenge, Tabellario said, will be reintroducing her to other sloth bears and teaching her to socialize with her own species — the sooner the better. That’s because hand-raised animals have a harder time mothering their own babies, Margulis said. Margulis has published studies on mice showing that pups that were raised in the same cages as their mothers were more successful mothers than mice raised alone. And in the primates she worked with, some hand-raised gorillas had to be taught to nurse and care for a baby.

“You can get into that vicious cycle. You have an adult that hasn’t been raised by mother, that hasn’t had experience with siblings or littermates, and they often aren’t good mothers as a result,” Margulis explained.

Bernier disagrees. Maternal care in animals is so varied, even among individuals in a zoo collection, that there isn’t enough evidence to say that hand-raising has a negative effect, he said.

“I’ve seen the same species where the females all treat their young differently. Some are very protective; some are lackadaisical,” Bernier said. “Their personality is very wide-ranging, and what they’re willing to tolerate is myriad. I think it’s a pretty natural process, and we let them go through the normal steps until they reject offspring.”

There the cheetahs have an advantage, Crosier said, because adoption is an option. It hasn’t been tried often in zoos, she said, but cheetahs in the wild occasionally adopt cubs whose mothers have been killed. She’s hopeful that Mitty, a cheetah at the zoo with six cubs of her own, will foster Ally’s litter.

“We are very hopeful that one of our females that is currently raising six of her own cubs will at some level accept these other three cubs,” Crosier said. “Every cheetah cub that is born in this population is critical for the future of the population. And we are at a point with our cheetah population in North America where if we don’t start producing a certain number of animals every year, we are going to not have cheetahs in the next 50 years in North America.”


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Source:
http://www.pbs.org/newshour/updates/baby-animals-rescued-mothers/

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Part II：Speed

【Time 2】
Article 2
Narwhal has the strangest tooth in the sea

Sometimes called the unicorn of the sea, the male narwhal’s tusk is actually a tooth, and it grows directly through the whale’s upper lip instead of pushing the lip aside. It’s an exuberantly large version of a canine tooth that grows in a spiral; the only tooth known to do so. Otherwise narwhals are practically toothless, with only vestigial stubs that stop growing during development and rarely emerge into the mouth.

This extreme anatomy has captivated dentist Martin Nweeia, who practices in Connecticut and teaches at Harvard University. For more than a decade, he has pioneered ways to study these difficult-to-reach Arctic whales, and he and his colleagues now describe in the April Anatomical Record that narwhals can detect changes in water salinity using only their tusks. The animals “don’t have a good sense of humor,” though, about being temporarily restrained for the testing, Nweeia says.


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Source:
https://www.sciencenews.org/article/narwhal-has-strangest-tooth-sea


【Time 3】
Article 3
Why Asian-American Students Outperform Their White Peers

When it comes to academic achievement, Asian-Americans outclass every other ethnic group, with more than half over age 25 holding a bachelor’s degree—well above the national average of 28%. To find what gives Asian-Americans a leg up, a team of sociologists scoured two long-term surveys covering more than 5000 U.S. Asian and white students. After crunching test scores, GPAs, teacher evaluations, and social factors such as immigration status, the team reports a simple explanation online today in the Proceedings of the National Academy of Sciences: Asian-American students work harder. The team found that students from all Asian ethnic groups put greater importance on effort than on natural ability. This outlook, the team argues, causes students to respond to challenges by trying harder and has a greater impact on Asian-Americans' academic achievement than does cognitive ability or socioeconomic status. However, the team says Asian-American students reported lower self-esteem, more conflict with their parents, and less time spent with friends compared with their white peers. The team suspects the high academic expectations or their "outsider" status in American society could be to blame.


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Source:
http://news.sciencemag.org/education/2014/05/scienceshot-why-asian-american-students-outperform-their-white-peers?rss=1


【Time 4】
Article 4
Afghan landslide was 'an accident waiting to happen'
Natural-hazards expert Dave Petley discusses the 2 May disaster in Ab Barak.

Dave Petley, who studies natural hazards at Durham University, UK, has seen his share of devastating landslides. But even he was startled by the scale of the 2 May disaster in northeastern Afghanistan, where a hillside saturated by heavy rains gave way above the village of Ab Barak. At least 350 and possibly more than 2,000 people died in the landslide, which came in two waves.

Petley spoke with Nature about the geology behind the tragedy.

How vulnerable is this region?
A 2011 study of northeast Afghanistan, using satellite imagery, found 34 previous examples of this type of landslide. They are quite common. You can divide the geology in this part of Afghanistan into two different types. The bedrock is a mixture of old crystalline rocks and some younger sediments, which are mostly impermeable and reasonably strong. But sitting on top of that is a thick layer of loess, which is windblown dust from the deserts to the north. It has big void spaces between the particles, which makes it weak if water gets into it. This is probably the most recent of a whole series of landslides.

How unusual was the death toll?
About every 2–3 years, somewhere in the world we get a rainfall-induced landslide that kills more than 1,000 people. They are more common than you might think. This particular landslide is interesting because the volume of material that moved is so large. These failures in loess tend to be really mobile, moving fast and for a long way. That’s clear because the landslide has come down into the valley and spread in both directions — the valley at the bottom of the slope appears to have been buried to a depth of 20 metres or more. It was just unlucky that people were in the way.

Did the landslide create new hazards?
The landslide material has blocked the valley completely, so that water flowing down is now ponding and a lake is forming. That can be rather a dangerous situation, because when the water level gets sufficiently high, water starts to run across the landslide and flood down the valley. In the past, [in other areas], some of those floods have caused significant problems.


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【Time 5】


Could anyone have seen this coming?
The Google Earth image of the area, though it's not particularly high resolution or even recent, suggests that this landslide was easily identifiable in advance. This was an accident that was waiting to happen.

What can be done to reduce death tolls in future landslides?
About 85% of people killed in landslides [are] in Asia, nearly all in very poor countries. This is terrain that is tectonically active, with steep slopes and lots of weathering. Often there is earthquake activity that destabilizes slopes, and seasonal rainfall patterns such as typhoons or monsoons. But with appropriate programmes we can try to reduce losses.

A mapping exercise of potentially dangerous large slopes in Afghanistan would cost a fraction of the losses from this single event. When you find a particularly dangerous slope, you can have a relatively low-cost monitoring scheme where people measure the distance between pegs [to see if a hillside is starting to fail]. And then they can get out of the way when it starts moving or during periods of heavy rain.

Does the 22 March landslide in Washington state, which killed more than 40 people, show that developed countries are also at risk?
When that happened I was very taken aback. If you look outside of Asia, it was really the first event to kill that number of people in a rich country in recent years. It’s a bit difficult to understand that landslide at the moment. If you compare it statistically with previous events, it was faster than we would normally expect, and spread over a bigger area. The unfortunate thing is that despite the warnings that another failure was likely, and clear reports that suggested it was a dangerous slope, people were living in quite close proximity to it.


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Source:
http://www.nature.com/news/afghan-landslide-was-an-accident-waiting-to-happen-1.15158


【Time 6】
Article 5
Physics Predicts U.S. Voting Patterns

Building on theories used to describe magnets, scientists have put together a model that captures something very different: voting patterns in U.S. presidential elections. In the model, just two factors directly influence someone’s vote: the proportion of Republicans and Democrats in a voter’s home county and that same proportion in the county where they work. For example, a person who voted Republican in one election and lives in a politically neutral county but works in a heavily Democratic county would likely vote for a Democrat in the next election. Rather than trying to predict the winner in a series of elections, the researchers focused on the distribution of Republican margins of victory across U.S. counties as well as how correlations between two counties’ vote shares changed with the distance separating them, quantities more commonly used to describe the transition from a demagnetized block of iron to a magnetized one. Combining the model of social influence with U.S. census data on commuting patterns, the researchers predicted a bell curve distribution of county-level margins of victory and surprisingly long-range correlations between counties; that suggests that some counties, at least, could feel the effects of social pressures in counties on the other side of the nation, they report this month in Physical Review Letters. What’s more, those patterns were a close match to the actual election data, putting a new spin on some old ideas.


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Source:
http://news.sciencemag.org/physics/2014/04/scienceshot-physics-predicts-u.s.-voting-patterns