【Native Speaker每日综合训练—39系列】【39-18】 科技

zxppx

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公益申请名额，每月一名

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Part I: Speaker

Martian Soil Salts May Make Water Ice All Wet
Within a Mars-like laboratory environment, perchlorate salts known to exist on Mars were able to lower the freezing point enough to get ice to turn to liquid water. Clara Moskowitz reports.   

If Martians exist, even the microbial sort, they probably need liquid water. Temperatures on the surface of the red planet are below freezing, but signs exist that water flowed in the past—and perhaps still does, thanks to a Martian version of anti-freeze.

Salts lower the freezing point of water, as anyone knows who’s thrown salt on an icy sidewalk. And both NASA’s Phoenix and Curiosity missions found salts called perchlorates sprinkled around the Martian surface.

To see how perchlorates might act on Mars, researchers recreated the pressure, humidity and temperature of the planet inside a metal cylinder. They put a thin layer of perchlorates on top of water ice inside the chamber. Within minutes, droplets of liquid water formed, even at minus 100 degrees Fahrenheit.

Some scientists thought perchlorates might condense water vapor from the atmosphere. But within the cylinder, no liquid water formed in the presence of salts, either alone or on Mars-like soil, unless ice was present too. The study is in the journal Geophysical Research Letters. [Erik Fischer et al, Experimental evidence for the formation of liquid saline water on Mars]

The finding study could explain mysterious globules seen on the leg of the Phoenix in 2008. The lander may have been dotted with drops of otherworldly water.

—Clara Moskowitz

Source: Scientificamerican
http://www.scientificamerican.com/podcast/episode/mars-salt-wet-h2o/

[Rephrase 1, 1:33]

zxppx

Part II: Speed

'Hot Jupiter' measurements throw water on theory
Dry atmospheres of three exoplanets challenge ideas of how planets form.
BY Mark Zastrow | 24 July, 2014

[Time 2]

Scientists searching for worlds outside of the Solar System say that three such planets — distant gas giants that resemble Jupiter — are surprisingly dry.

The atmospheres of these exoplanets, known as ‘hot Jupiters’, contain between one-tenth and one-thousandth water vapour than predicted, measurements from the Hubble Space Telescope show. The findings, published 24 July in Astrophysical Journal Letters1, are at odds with theories of how planets form.

The study re-analyses observations of the exoplanets HD 189733b, HD 209458b and WASP-12b, which are 20–270 parsecs (60–870 light years) away from Earth. As each exoplanet crossed in front of its host star, Hubble observed the spectrum of infrared light filtering through the planet’s atmosphere. A team led by Nikku Madhusudhan, an astronomer at the University of Cambridge, UK, then used atmospheric models to determine the combination of elements that produced each planet’s spectrum.

The results suggest that the environments of all three hot Jupiters are drier than Jupiter itself. HD 209458b, which yielded the most precise measurements, seems to be the driest — its atmosphere is 1,000 times drier than Jupiter's, and 100 times drier than the Sun's.

Under current theory, planets should accumulate molecules such as water faster than their host stars, write the authors. Hot Jupiters typically form in water-rich areas of solar systems and migrate toward their host stars. But Madhusudhan says the new findings suggest that these theories may have to be revised.

[235 words]

[Time 3]

However, some scientists favour another possible explanation. Clouds at high altitudes above the exoplanets could be obscuring Hubble’s view of the water vapour buried deeper in the atmosphere. If this is true, “their results are completely undermined,” says Adam Burrows, an astronomer at Princeton University in New Jersey, who was part of the team whose data on HD 209458b were analysed in the current study2. He was not involved with the latest study.

Madhusudhan thinks that it is possible, but not likely, that clouds are skewing his results. The particles would have to be high in the atmosphere, above the water vapour, for this to be true. That would place the clouds in the thinnest part of each exoplanet's atmosphere, but they could be too heavy to stay aloft. The clouds would also need to survive in the wide range of temperatures the three planets' atmospheres span — 900–2,200 ºC — which models can't yet explain. “There is just no candidate cloud composition or physics that can do it,” he says.

But the fact that is is unclear how such clouds could be made doesn’t mean they don’t exist, says Zachory Berta-Thompson, an astronomer at the Massachusetts Institute of Technology in Cambridge. He and his colleagues have studied a hot rocky planet named GJ 1214b and determined that clouds were present high in its atmosphere, in a layer even thinner than those that Madhusudhan are considering3. “It’s a little bit frustrating that these planets are slightly more complicated than we’d like them to be,” Berta-Thompson says.

Researchers hope that telescopes now in development, including NASA’s James Webb Space Telescope and some large ground-based facilities under construction, will provide higher-resolution data that can dispel some of the current confusion.

[287 words]
Source: nature
http://www.nature.com/news/hot-jupiter-measurements-throw-water-on-theory-1.15618


Dinosaur-killing asteroid hit at just the wrong time
Animals might have survived if impact happened a few million years earlier or later.
BY Alexandra Witze | 28 July, 2014

[Time 4]

Just before a large asteroid slammed into the Earth 66 million years ago, the diversity of plant-eating dinosaur species declined slightly, a new study suggests. That minor shift may have been enough to doom all dinosaurs when the space rock hit.

The scarcity of plant-eaters would have left them more vulnerable to starvation and population collapse after the impact, with consequences that rippled all the way up the food chain.

“The asteroid hit at a particularly bad time,” says Stephen Brusatte, a palaeontologist at the University of Edinburgh, UK. “If it had hit a few million years earlier or later, dinosaurs probably would have been much better equipped to survive.”

Brusatte and his colleagues describe this nuanced view of the famous extinction in Biological Reviews.

Palaeontologists have argued for decades about whether dinosaurs were doing well when the asteroid hit, or whether they were experiencing a worldwide drop in the number of species. To explore this question, the study pulled information from a database on global dinosaur diversity, including hundreds of fossils found in the past decade.

Localized decline
The scientists used analytical methods to account for the fact that some fossil-bearing rock formations are well-studied and others are not, which could distort the apparent number and distribution of dinosaur species. They found most dinosaurs thriving right up until the impact. “If we look at the global picture, we don't see evidence for a long-term decline,” says team member Richard Butler, a palaeontologist at the University of Birmingham, UK. “In no sense were dinosaurs doomed to extinction and the asteroid just kind of finished them off.”

But in North America, in the last 8 to 10 million years before the asteroid hit, two major groups of herbivores — duck-billed dinosaurs and the group of horned dinosaurs that included Triceratops — did decline slightly. In some places multiple species shrank to just one species. That may be because cooler climates changed the types of vegetation available to eat, says Michael Benton, a palaeontologist at the University of Bristol, UK. Plenty of dinosaur groups had recovered from such small population drops before, but not this time.

A 2012 study that modelled ancient food webs may help to explain why, says Butler. Computer simulations suggested that just a small change in dinosaur diversity made ecosystems much more likely to collapse after big environmental perturbations — such as widespread climate change brought on by an asteroid impact. Plants would have withered up; plant-eating dinosaurs would have starved; and meat-eating dinosaurs would have had little to prey on.

[421 words]

[Time 5]

What if?
The latest study rounds up many of the discoveries of recent years, says David Archibald, a palaeontologist at San Diego State University in California. “From my reckoning much of it is pretty much spot on,” he says. “It is almost certainly the impact that kills off the dinosaurs.” But he disagrees with some of the data. In a review in press with the Geological Society of America, Archibald compares several rock formations from near the end of the time of dinosaurs, in Canada and the United States. He finds that the two-legged, primarily meat-eating dinosaurs known as theropods were also declining.

Brusatte says that the differences boil down to how researchers account for how well-studied or well-preserved various fossil-bearing rocks are. “It’s really only now with all these new dinosaur discoveries that people are able to even think about the nuances in any kind of detail,” he says.

The extinction set the stage for the modern world, Butler notes. Although one lineage of dinosaurs survived as modern birds, mammals began their rise only after the dinosaurs were out of the picture. ”That may never have happened if dinosaurs had never gone extinct,” says Butler. ”It think it's very likely that if the asteroid hadn't hit, we would still have dinosaurs around today.”

[214 words]
Source: nature
http://www.nature.com/news/dinosaur-killing-asteroid-hit-at-just-the-wrong-time-1.15616


Wonders of the northern lights
Photographer captures aurora's glow above Iceland’s Kirkjufell Mountain
BY THOMAS SUMNER| 25 July, 2014

[Time 6]

Tens of kilometers above the icy waterfalls surrounding Iceland’s Kirkjufell Mountain, Earth’s magnetic field drags electrons from the sun to their visually stunning demise. The zooming particles collide with nitrogen and oxygen in the upper atmosphere, an interaction that produces a brilliant blue-green light show called an aurora.

Photographer Nicholas Roemmelt captured this scene on a moonlit night in March. The shot won him third prize in the “Beauty of the Night Sky” category of the recent International Earth & Sky Photo Contest.

While scientists know the basics of how auroras form, many aspects of the lights elude explanation. On March 3, NASA launched a rocket into the heart of an aurora shining above Venetie, Alaska, to measure the particles and electric fields at work. By combining the rocket’s data from its 10-minute flight with observations from the ground, researchers received an unprecedented look inside the northern lights. NASA hopes the mission will illuminate mysteries such as the origin of auroral curls, which look like cream swirling in a cup of coffee.

[172 words]
Source: sciencenews
https://www.sciencenews.org/article/wonders-northern-lights

zxppx

Part III: Obstacle

How bird flocks are like liquid helium
BY Marcus Woo | 27 July, 2014

[Paraphrase 7]

A flock of starlings flies as one, a spectacular display in which each bird flits about as if in a well-choreographed dance. Everyone seems to know exactly when and where to turn. Now, for the first time, researchers have measured how that knowledge moves through the flock—a behavior that mirrors certain quantum phenomena of liquid helium.

"This is one of the first studies that gets to the details of how groups move in unison," says David Sumpter of Uppsala University in Sweden, who was not part of the study.

The remarkable accord with which starling flocks fly has long puzzled researchers and bird watchers alike. In the 1930s, the ornithologist Edmund Selous even suggested that the birds cooperate via telepathy. Researchers have since turned to more scientifically sound ideas, using mathematical models.

In the 1990s, physicist Tamás Vicsek of Eötvös Loránd University in Budapest came up with one of the more successful models, which is based on the principle that each bird flies in the same direction as its neighbors. If a bird angles right, the ones next to it will turn to stay aligned. Although this model reproduces many features well—how a flock swiftly aligns itself from a random arrangement, for example—a team of researchers from Italy and Argentina has now discovered that it doesn't accurately describe in detail how flocks turn.

In their new study, the team, led by physicists Andrea Cavagna and Asja Jelic of the Institute for Complex Systems in Rome, used high-speed cameras to film starlings—which are common in Rome and form spectacular flocks—flying near a local train station. Using tracking software on the recorded video, the team could pinpoint when and where individuals decide to turn, information that enabled them to follow how the decision sweeps through the flock. The tracking data showed that the message to turn started from a handful of birds and swept through the flock at a constant speed between 20 and 40 meters per second. That means that for a group of 400 birds, it takes just a little more than a half-second for the whole flock to turn.

"It's a real tour de force of measurement," says Sriram Ramaswamy of the Tata Institute of Fundamental Research’s Centre for Interdisciplinary Sciences in Hyderabad, India, who wasn't part of the research.

The fact that the information telling each bird to turn moves at a constant speed contradicts the Vicsek model, Cavagna says. That model predicts that the information dissipates, he explains. If it were correct, not all the birds would get the message to turn in time, and the flock wouldn't be able to fly as one.

The team proposes that instead of copying the direction in which a neighbor flies, a bird copies how sharply a neighbor turns. The researchers derived a mathematical description of how a turn moves through the flock. They assumed each bird had a property called spin, similar to the spins of elementary particles in physics. By matching one another's spin, the birds conserved the total spin of the flock. As a result of that conservation, the equations showed that the information telling birds to change direction travels through the flock at a constant speed—exactly as the researchers observed. It's this constant speed that enables everyone to turn in near-unison, the team reports online today in Nature Physics.

The new model also predicts that information travels faster if the flock is well aligned—something else the team observed, Cavagna says. Other models don’t predict or explain that relationship. "This could be the evolutionary drive to have an ordered flock," he says, because the birds would be able to maneuver more rapidly and elude potential predators, among other things.

Interestingly, Cavagna adds, the new model is mathematically identical to the equations that describe superfluid helium. When helium is cooled close to absolute zero, it becomes a liquid with no viscosity at all, as dictated by the laws of quantum physics. Every atom in the superfluid is in the same quantum state, exhibiting a cohesion that's mathematically similar to a starling flock.

The similarities are an example of how deep principles in physics and math apply to many physical systems, Cavagna says. Indeed, the theory could apply to other types of group behavior, such as fish schools or assemblages of moving cells, Sumpter says.

Other models, such as the Vicsek model or others that treat the flock as a sort of fluid, probably still describe flock behavior over longer time and length scales, Ramaswamy says. But it's notable that the new model, which is still based on relatively simple principles, can accurately reproduce behavior at shorter scales. "I think that's cool," he says. "That's an achievement, really."

Sumpter agrees. "It's kind of reassuring we don't need to think about the telepathic explanation," he says.

[803 words]
Source: nature
http://news.sciencemag.org/math/2014/07/how-bird-flocks-are-liquid-helium

疏离无罪

沙发~~~~~~~~~~~~~~~~~~~~··

Speaker: Ice can lower the freezing point of water.Salt called perchlorates found on the Mars may make it possible that there is water on this planet.But some scientists said that in the experiment,no water formed in the presence of water unless ice was present,too.

01:11
Scientists recently found three distant gas giants that resemble Jupiter but surprisingly dry.This discovery may change the old theory of the fomation of planet.

01:07
Some scientists thought that clouds at high altitudes above the exoplanets may be a good explanation,though others argued against this view.Further study and data is needed to solve this issue.

01:58
New study said that If the asteroid hit had hit a few million years earlier or later, dinosaurs probably would have been much better equipped to survive.Because there happened to be a species decline.

00:58
Althought the data seems to have some problems,it can still be a trustful idea.The extinction of dinosaurs set the stage for the modern world and the rise of mammals.

00:59
NASA sent a rocket into the northern light to have a further study about it.

04:54
A study about how bird groups move in unison.
An old principle is that each bird flies in the same direction as its neighbors.
A new study used some new and high technology to find out the mechanism.They found out that instead of copying the direction in which a neighbor flies, a bird copies how sharply a neighbor turns and the information telling birds to change direction travels through the flock at a constant speed.The new model also predicts that information travels faster if the flock is well aligned.

charming9386

29 July
SPEED
01:26 [235 words]
Main idea: hot Jupiter is dryer
Structure:
              1)  The background
                  the three plants are knwon to be "hot Jupiter" because they are dryer.
              2)  The contrast
                  "Hot Jupiter" are at odds with the theory how the planets form   
              3)  The research
                  Scientists started observations.In US,the scientist used models to determine the elements
              4)  The result
                  We find that the "hot Jupiter" are more dryer than their main planets
              5)  The conclusion
                  the theory may be inversed

02:38 [421 words]
Main idea: killing dianosaur asteroid hits at the worong time
Structure:
              1)  The background
                  Before asteroid,the dianosour declined slightly.BUT the small shift mede the dianosour extincted.
              2)  The claim
                  Unless the asteroid hit at the worong time ,the dianosaur would live better
              3)  The research of location
                  Scientists started studies the fossil of dianosaur in order to find the number and spread in the ancient time
              4)  The result
                  They find that there was no obvious decline and there was ever a climate change which resulted in a slight decline in the number.but
                  recovered later.
              5)  The conclusion
                  scientists claim that because the asteroid resulted in climate change,the dianosaur lived in a hard time in which they were starved and had little
                  food.

01:04 [214 words]
Main idea: some scientists have new findings.** finds that meat-eating dinosaurs were also declining. ** disagrees some data in the fossils of dianosaurs.
*** thinks that if the asteroid had not hit,the human dianosaur would have lived until today.

01:09 [172 words]
Structure:
              1)  the theory about how the aurora form
                  In IKM ,people observed the aurora.
              2)  The photo
                  ** shot a photo and was awarded "the third award" of "the beauty of night"
              3)  The research of location
                  NASA collect data about eletric fields and particles and hope to see the aurora

Obstacle
04:15 [803 words]
Main idea: the startling flok and model
Structure:
              1)  The background
                  The startling flocks are like liquid helium even though everyone konws when and where they turn.
              2)  The research in 1930s
                  The birds cooperate via telepathy
              3)  The research in 1993
                  Each bird flies in the same direction as its neighbors                  
              4)  The new study
                  The scientists use high-speed cameras to observe and the starling birds just took a little time to turn
              5)  The conclusion ----The similarity and model
                  The principles can be applied into many flocks as well as the new models can be.And they refute the telepathy

charming9386

今天总结了SC50题 明天是90SC 效率 high ！！！！视力就被这电脑弄坏了 好困 明天大清早看5篇阅读 现在已经坚持不下去了
choreographed
adj. 精心设计的；刻意安排的
vt. 精心设计（choreograph的过去式）

unison
n. 和谐；齐唱；同度；[声] 同音

telepathy
n. 心灵感应；传心术

aligned
adj. 对齐的；均衡的
v. 结盟（align的过去式）；使成一直线

cherry6891

Thanks ppx ~~
39-18
Obstacle
A new research found out how the birds could fly in a certain sharp--it mirrors the quantum phenomenon of liquid helium

1930-telepathy
Later-each bird flies the same direction as it's neighbor
Latest-the bird copies how sharply the neighbor turns

Time2-3
How dry the exoplanet is
Current theory: J formed in water rich area and mitigate toward to the host star
The cloud in the high latitude skewed the result

Time4
The diversity of plant eating dinosaur declined slightly before the asteroid hit the Earth
Looking from the global picture,not multi kinds declined but just certain kind
If the hit before the declined ,more dinosaur would survive

Time 5
The result is all depend on the fossil-bearing rocks we studied

Time6
How does aurora form?--zooming particles meet with nitrogen and oxygen
The pictures of aurora wined him the big prize

CatherineTSIM

[Speaker]
Scientists recreated a atmosphere in the metal cylinder and prove that there is water on Mars.

[Time 2] 1’29’’
Main idea: The 3 hot Jupiter are dryer than Jupiter itself.
Structure:
(1)        The background of the hot Jupiter
(2)        The research find that hot Jupiter are dry
(3)        The new finding suggest that the theory is reverse
[Time 3] 1’38’’
Main idea: If the cloud theory is proved, it can undermine the water theory
Structure:
(1)        The conception of cloud theory
(2)        The particular cloud can not be made
(3)        The cloud may exist even it can not be made
(4)        Hope that there is a high-definition telescope can deal with the confusion
[Time 4] 2’53’’
Main idea: The asteroid and the climate may cause the dinosaur to decrease
Structure:
(1)        The Paleontologists are argue that whether asteroid may cause the dinosaur to decrease
(2)        Someone claim that it is the asteroid cause the dinosaur to decrease, someone argue that it is the cold weather. However the conclusion is that it is the climate brought by the asteroid cause a group of dinosaur to decrease and influence the whole ecosystem.
[Time 5] 1’00’’
Main idea: The scientists try to find out what form an aurora.
Structure:
(1)        The background of aurora and a photographer won the prize by capture the aurora phenomenon.
(2)        The scientist send a rocket to the middle of the aurora and try to find what form the aurora.

[Obstacle] 5’54’’
Main idea: To discover how the bird flock change their direction
Structure:
(1)        Before, people suggest that is the telepathy cause the bird flock to change the flying direction together.
(2)        People find that bird flock fly follow its neighbor to change the direction.
(3)        The high-definition camera shows that almost all the bird changes the direction in the same constant.
(4)        The conception in mathematical “spin” show that each bird in the flock change its direction by the constant speed of the flock.
(5)        The theory above just similar to the conception of liquid helium.

练习的第十天。不再只是记住main idea，而是第一次尝试用main idea和structure来分析文章了。
觉得略有些吃力。有时候要回朔一下文章才可以完成structure，真心希望自己能继续用structure，以后还可以不用回朔，再接再厉！
今天的天文学文章有点蒙。。。不过Aurora比较简单。
obstacle就完全是传统的科技文，各种scientist讨论意见。比较容易定structure。
加油！

醒醒Shine

[speaker]
salts soil on Mars, water anti-freeze

[time2]1:37
exoplanet=hot Jupiters, 3, dry
old theory: form in water-rich, migrate to host

[time3]1:51
new theory:high altitude clouds obscure Hubble===> water vapour deeper
still unclear,but do exist
need to go further

[time4]2:40
new finding: dinosaur slight declined before asteroid hit
localized decline evidence

[time5]1:20
opposite: differ boil down to hwo reaserchers account for fossil , nuance
what if: they still around


[time6]1:03
aurora
photo got prize
mission sent inside, plan to illuminate mysteriesrigin


[obstacle]5:47
topic: folck of starlings flies as one
1 old explanation:
ES 1930 telepathy
TV 1990 copy neighbors
2 new study:
handful brids--->swept through the flock
TV and new one: TV copy direction; New copy turns
3 app:identical to helium in absolute 0
4 opinion: achievement

今天尝试开始计时。按照抓抓当年的目标，speed要力求1min完成，obstacle是6min以内。
感触：
1 有了时间限制以后，就不得不开始区分重读和略读。
2 压力下的阅读，就开始注重捕捉main idea出现的地方。以obstacle为例，典型科普文，先说了老观点（还是要记老观点的核心词，比如这篇就是copy内容的一个对比），再说新观点，那么新观点自然是main idea。但是！光看清了大逻辑还不够，现在力求自己抓住小逻辑：也就是老的是copy direction，而新的是copy turns。特点就是新观点的速度更快，能解释更多现象。最后谈了下应用对比（物理和数学）。自然而然得到结论是这个新观点很棒啦，achievement是非常好的肯定词。
生词不多！抓得越来越顺。速度要有待继续提升。

liuwenying

Time 2 1'50
Main idea :The three( hot Jupiters) planets are drier
Structure: the Hubble observed the three exoplanet and found that they are drier than the their host star --the Jupiter
             Then then test their spectrum. the findings may contradict to the current theory about how planet forms by accumulating vapor.

Time 3 1'47
Main idea :There is another possible explanation
Structure: 1) The clouds in the high latitudes may make the observation obscure. The water may in the deep place of the planet.
             2) Scientist argued about the existence of the clouds under extreme environment.
             3) Z said that a kind of cloud is possible to live in even thinner place.
Conclusion: however the explanation still needs to be proven and more accurate facilities need to be manufactured.  

Time 4 2'48
Main idea Is the distinction of dinosaurs really because the asteroid hit the earth at a wrong time?
Structure: Research found that just before the asteroid hit the earth the number of dinosaurs decreased. They assume the asteroid hit the earth at a wrong time.
            2) Researchers found in some place(忘了好像英国） the diversity of meat-eating dinosaurs did not decrease as they previously thought by analyse the fossils but In American the herbivores really experienced a sharp decline due to climate change.
          3) the researcher assumed that the asteroid impact brought earth the climate change and the dinosaurs did not survive in the change.

Time 5 1'15
Main Idea : the dinosaur distinction bring a new era
Structure : another fossil analysis substantiate the predictionr
               scientists contend that the distinction of dinosaurs brought living space for other animals. If the asteroid had not hit the earth we would have to live with dinosaurs.

Time 6 1'10
How the aurora formed and the research about the aurora made by NaSA

Time 7 5'16
Main idea : The bird flock is kind of similar to the Liquid Helium
Structure 1、 1930 one theory suggests that bird cooperate by the telepathy.
2、somebody suggests the bird turns direction according to its neighbors            
3、 a group of researchers use camera to document the bird flock  
                They find bird flock turn direction at a constant speed.
4、they also find the more allied the bird flock the more organised the flock performed.
5、The bird flock is similar to the structure of liquid helim.