【Native Speaker每日综合训练—29系列】【29-09】科技

zxppx

Official Weibo: http://weibo.com/u/3476904471
大家好!胖胖翔来了! 今天的文章以天文为主，看到过绿色的闪电吗？来自宇宙最早的光线能带给我们什么讯息！此外，养狗狗还有意想不到的好处哦，both for you and your children!

Part I：Speaker

【Rephrase1】
Article 1
Even An 85 MPH Highway Can't Fix Austin's Traffic Tangle


[Dialog, 7: 46]

Source:
http://www.npr.org/2013/12/17/248757580/even-an-85-mph-highway-cant-fix-austins-traffic-tangle

zxppx

Part II：Speed

【Time 2】
Article 2
Green lightning may be caused by positive charges, or by camera lens

SAN FRANCISCO — A zigzag of green lightning that flashed above a volcano in 2008 could have gotten its color from a cluster of positive charges.

The freak bolt, snapped by a photographer during an eruption of Chile’s Chaitén volcano, may be a different type of lightning than the kind sent down from thunderclouds, suggested atmospheric physicist Arthur Few of Rice University in Houston at the American Geophysical Union’s fall meeting on December 9.

In thunderstorms, negative charges jump from clouds to the ground in a white-hot streak. But a green color could emerge if the bolt formed from positive charges in the volcano’s ash plume, Few said. Positive charges would attract electrons that could excite nearby oxygen molecules. When oxygen molecules calm down, they emit green light.

But there may be a simpler explanation. Since Few reported his idea, several photographers have suggested to him that the color might be a trick played by the camera lens. Flip the photograph’s largest white lightning bolt upside down and take its mirror image, they say, and the result looks just like the green streak.

The camera, Few said, could somehow have recorded a green ghost of the brighter white flash.


Source:
字数[198]
https://www.sciencenews.org/article/green-lightning-may-be-caused-positive-charges-or-camera-lens

【Time 3】
Article 3
Water Vapor Plumes Erupt From Europa
Stay back! Geysers of vapor—a couple of hundred kilometers tall and possibly erupting at supersonic speeds—occasionally spew from the south polar regions of Europa, one of Jupiter’s ice-covered moons, a new study suggests.

Europa, an ice-swaddled jovian satellite that has long fascinated both scientists and science fiction writers, just got a bit more interesting. Data gathered by the Hubble Space Telescope suggest that plumes of water vapor hundreds of kilometers tall, possibly originating in a subsurface ocean, spew from the moon’s south pole. The phenomenon is similar to the sprays of ice particles found emanating from the saturnian moon Enceladus almost a decade ago.

Oxygen and hydrogen atoms emit or absorb certain wavelengths of ultraviolet light. If these telltale signs appear together in light from a distant object, they hint that water vapor might be present there, explains Lorenz Roth, a planetary astronomer at the Southwest Research Institute in San Antonio, Texas. So, late in 2012, in hopes of detecting vapor plumes, he and his colleagues used the Hubble Space Telescope to observe Europa in ultraviolet light. Oxygen is often present in Europa’s tenuous atmosphere, and sometimes it’s more concentrated in the space above the moon’s southern hemisphere, Roth says. But for one lengthy interval during the observations, the team spotted emissions from hydrogen (at a wavelength of 121.6 nanometers) in the same region. Because the satellite’s surface is covered with ice, the clearest observations came from portions of the purported plumes that were silhouetted against space rather than against the moon itself.

That whiff of hydrogen, which apparently lasted no more than 7 hours, burst forth when Europa was farthest from Jupiter in its orbit, the researchers report today in San Francisco at the fall meeting of the American Geophysical Union and online in Science. Intermittent and short-lived plumes of water vapor, possibly as much as 200 kilometers tall, are the best explanation for the observations, the researchers contend.


字数[287]


【Time 4】


The orbital timing of the plumes, probably not coincidentally, is the same as that for Enceladus, Roth says. That moon’s sprays of ice are most profuse when Enceladus is farthest from Saturn in its orbit. Most likely, scientists have proposed, the tidal flexing induced in a moon’s icy surface causes cracks in polar regions to open widest while the satellite is farthest from its parent planet but clamp shut at other times. It’s not clear whether Europa’s plumes, like those on Enceladus, are triggered by icy surfaces of a surface fracture rubbing together—somewhat akin to the sides of a tectonic fault scraping past one another—or whether they represent water vapor spewing from Europa’s subsurface ocean through narrow cracks in the moon’s polar ice at supersonic speeds, Roth says.

The new finding “is very exciting,” says Geoffrey Collins, a planetary scientist at Wheaton College in Norton, Massachusetts. “I’m not sure that this paper clinches the case for Europa plumes, but you can bet that it will inspire a lot of follow-on work.” Nevertheless, he notes: “If the plumes are real, this shows that Enceladus isn’t the only icy moon where this happens. … The resemblance between Europa and the south polar terrain on Enceladus has always been striking to me, so perhaps it shouldn’t be surprising if they share more in common than just looks.”

Christophe Sotin, a planetary scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California, calls the new results “quite compelling.” But it’s important to note, he says, that what’s been discovered is evidence of individual hydrogen and oxygen atoms. To show that those atoms are bonded together into water vapor or a similar substance, observations at other wavelengths would be needed.

If Europa’s vapor plumes are confirmed by more observations, “that would change the kinds of instruments you’d want to install on future probes to the moon,” Sotin continues. In particular, sensors that could analyze the chemical composition of the plumes, either remotely or by sampling the material as it whizzed through the vapor, could provide keen insights into the chemical processes taking place on or deep beneath Europa’s icy surface.


字数[356]
Source:
http://news.sciencemag.org/chemistry/2013/12/water-vapor-plumes-erupt-europa


【Time 5】
Article 4
Want to Fight Allergies? Get a Dirty Dog
Mediator of microbes. A mouse study suggests dust from dogs affects gut bacteria, which in turn may protect against allergies.

A dog in the house is more than just good company. There’s increasing evidence that exposure to dogs and livestock early in life can lessen the chances of infants later developing allergies and asthma. Now, researchers have traced this beneficial health effect to a microbe living in the gut. Their study, in mice, suggests that supplementing an infant’s diet with the right mix of bacteria might help prevent allergies—even without a pet pooch.

"This paper elegantly illustrates how an environmental exposure protects against an allergic response by mediating the gut [bacteria]," says John Penders, a molecular epidemiologist at the Maastricht University Medical Center in the Netherlands, who was not involved with the work. "Studies like this provide new leads” about how one might manipulate the microbes in the gut to prevent or treat allergies.

More than a decade ago, U.S. researchers reviewing the health records of children with pets—dogs, and, to a lesser extent, cats—discovered that the kids were less likely to develop allergies and asthma than other children were. Other epidemiology studies in Europe have supported this connection, not just with pets, but with livestock as well. In 2010, Susan Lynch, a microbiologist at the University of California, San Francisco, showed that dogs who partly live outdoors shuttled environmental microbes into the house, some of which were also found in the human gut. She and others had already discovered that gut microbes affected immune responses, and so she wondered if the allergy protection provided by pooches happened via gut bacteria.

Lynch and her colleagues collected dust from a house with no animals and from a house with an indoor/outdoor dog. They fed that dust mixed with water to young mice and subsequently challenged the immune systems of the animals by giving them ground-up cockroaches or egg protein, two substances known to elicit allergic reactions in both rodents and people.

Mice receiving dust from the dog’s house weathered the challenge with little to no allergic reaction, but the other mice developed the mouse equivalent of a runny nose and revved up immune activity in their airways, the researchers report online today in the Proceedings of the National Academy of Sciences. In the dog dust-exposed mice, there were fewer allergy-associated immune cells and those that were present produced fewer immune system molecules that tend to lead to a strong reaction.  


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【Time 6】


Lynch’s team surveyed the kinds of bacteria in the mouse guts before and after exposure to the dust. Mice with the dog’s dust—and a less allergenic immune system—had an unusually large amount of a microbe called Lactobacillus johnsonii, the team reports. When it fed that bacterium to mice, those mice had a dampened allergic reaction, even without being exposed to the dog’s dust. Those mice also got less sick when infected with a virus that in humans can cause infants to later become asthmatic. “Our studies suggest that [this bacteria] is a critical mediator of airway protection against environmental insults,” Lynch says.

The new work adds another piece of evidence to the long-debated hygiene hypothesis, which holds that a modern, cleaner lifestyle may make us more susceptible to allergies, asthma, and autoimmune disorders. "There are a lot of studies which show exposure to pets and/or livestock reduces prevalence of allergic disorders, so this is an exciting and provocative step in understanding the mechanism behind that," says Suzanne Havstad, a biostatistician at Henry Ford Hospital in Detroit, Michigan, who was not involved with the work.

While it’s possible dust from the dog’s household directly transfers extra L. johnsonii into a person’s gut, Lynch suspects that other bacteria in the environment get carried into the house on the dogs, become airborne, and are swallowed. Once in the gut, they force a change in that microbial community that favors an increase in L. johnsonii already present.

Before anyone starts thinking about a bacteria-laced dietary supplement for their kids or adopting a dog just to fight allergies, much more work, including clinical studies, would need to be done, Lynch notes. "One should be very careful about transferring results from mouse models to humans,” adds Markus Ege, an epidemiologist at the University of Munich in Germany. “The experimental setting in mice is very artificial.”

Still, Penders says, “[t]he potential of Lactobacillus johnsonii as a probiotic in the prevention of allergic diseases is definitely something that should be further explored.”


字数[336]
Source:
http://news.sciencemag.org/biology/2013/12/want-fight-allergies-get-dirty-dog

zxppx

Part III： Obstacle

【Paraphase7】
Article 5
Subtle Distortion in Universe's Oldest Light: Swirls in Remnants of Big Bang May Hold Clues to Universe's Infancy

Dec. 13, 2013 — South Pole Telescope scientists have detected for the first time a subtle distortion in the oldest light in the universe, which may help reveal secrets about the earliest moments in the universe's formation.

The scientists observed twisting patterns in the polarization of the cosmic microwave background -- light that last interacted with matter very early in the history of the universe, less than 400,000 years after the big bang. These patterns, known as "B modes," are caused by gravitational lensing, a phenomenon that occurs when the trajectory of light is bent by massive objects, much like a lens focuses light.

A multi-institutional collaboration of researchers led by John Carlstrom, the S. Chandrasekhar Distinguished Service Professor in Astronomy & Astrophysics at the University of Chicago, made the discovery. They announced their findings in a paper published Sept. 30, 2013, in the journal Physical Review Letters -- using the first data from SPTpol, a polarization-sensitive camera installed on the telescope in January 2012.

"The detection of B-mode polarization by South Pole Telescope is a major milestone, a technical achievement that indicates exciting physics to come," Carlstrom said.

The cosmic microwave background is a sea of photons (light particles) left over from the big bang that pervades all of space, at a temperature of minus 270 degrees Celsius -- a mere 3 degrees above absolute zero.

Measurements of this ancient light have already given physicists a wealth of knowledge about the properties of the universe. Tiny variations in temperature of the light have been painstakingly mapped across the sky by multiple experiments, and scientists are gleaning even more information from polarized light.

Light is polarized when its electromagnetic waves are preferentially oriented in a particular direction. Light from the cosmic microwave background is polarized mainly due to the scattering of photons off of electrons in the early universe, through the same process by which light is polarized as it reflects off the surface of a lake or the hood of a car. The polarization patterns that result are of a swirl-free type, known as "E modes," which have proven easier to detect than the fainter B modes, and were first measured a decade ago, by a collaboration of researchers using the Degree Angular Scale Interferometer, another UChicago-led experiment.

B modes can't be generated by simple scattering, instead pointing to a more complex process -- hence scientists' interest in measuring them. Gravitational lensing, it has long been predicted, can twist E modes into B modes as photons pass by galaxies and other massive objects on their way toward earth. This expectation has now been confirmed.

To tease out the B modes in their data, the scientists used a previously measured map of the distribution of mass in the universe to determine where the gravitational lensing should occur. They combined their measurement of E modes with the mass distribution to provide a template of the expected twisting into B modes. The scientists are currently working with another year of data to further refine their measurement of B modes.

The careful study of such B modes will help physicists better understand the universe. The patterns can be used to map out the distribution of mass, thereby more accurately defining cosmologically important properties like the masses of neutrinos, tiny elementary particles prevalent throughout the cosmos.

Similar, more elusive B modes would provide dramatic evidence of inflation, the theorized turbulent period in the moments after the big bang when the universe expanded extremely rapidly. Inflation is a well-regarded theory among cosmologists because its predictions agree with observations, but thus far there is not a definitive confirmation of the theory. Measuring B modes generated by inflation is a possible way to alleviate lingering doubt.

"The detection of a primordial B-mode polarization signal in the microwave background would amount to finding the first tremors of the Big Bang," said the study's lead author, Duncan Hanson, a postdoctoral scientist at McGill University in Canada.

B modes from inflation are caused by gravitational waves. These ripples in space-time are generated by intense gravitational turmoil, conditions that would have existed during inflation. These waves, stretching and squeezing the fabric of the universe, would give rise to the telltale twisted polarization patterns of B modes. Measuring the resulting polarization would not only confirm the theory of inflation -- a huge scientific achievement in itself -- but would also give scientists information about physics at very high energies -- much higher than can be achieved with particle accelerators.

The measurement of B modes from gravitational lensing is an important first step in the quest to measure inflationary B modes. In inflationary B mode searches, lensing B modes show up as noise. "The new result shows that this noise can be accounted for and subtracted off so that scientists can search for and hopefully measure the inflationary B modes underneath," Hanson said. "The lensing signal itself can also be used by itself to learn about the distribution of mass in the universe."


字数[829]
Source:
http://www.sciencedaily.com/releases/2013/12/131213201038.htm

小鱼上树

谢谢小胖~

29-09

Speaker

Austin was once a quiet and lay back town. Now everywhere isbackup around the town. It’s the largest city in America but only has one statehighway going through. Government is trying to free the toll way and doanything to improve. People start rent downtown apartment so they don’t need tospend 2 hours commuting. The traffic situation turned to be a perfect topicduring get together.

2 297 1min45

5 392 2min18

6 336 1min51

There’s increasing evidence that exposure to dogs andlivestock early in life can lessen the chances of infants later developingallergies and asthma-gut microbes affected immune responses-feed the mouse withdog’s dust-this is an exciting and provocative step in understanding themechanism behind that-The experimental setting in mice is very artificial.

sherlock1992

谢谢小胖~
Speaker:
Austin, a progressive city, hasn't made much progress fixing a snarling traffic problem.
Speed:
T2-1'37''
T3-2'23''
T4-2'36''
T5-2'54''
T6-2'11''
Obstacle-7'30''
MI:subtle distortion->big bang clues.
E modes<generated by simple scattering, ezy acquired>--------gravitational lensing-------->B modes <not ezy>.
B->better universe-understood.
B---------gravitational waves-------------->inflation theory
gra. turmoil->gra. waves.

kimwang53

谢谢ppx~~

2.09
1.51
plumes of water vapor spew from the moon's south pole.
2.46
2.51
exposure to dogs and livestock in your early life can lesson the chances of infants later developing allergies and asthma.
Mice receiving dust from the dog has little allergic reaction while other mice have lots of allergic reacions
2.49
the bacteria even works in the mice which did'nt get exposure with dogs.
clean lifestyle may make us more susceptible to allergies...
many parents adopt a dog just for preventing clergy. from their kids.
but the suggestion is that they still need to be more carefull. they need more reseaches and evidence.

miyini

两天都是首页 尾      

2013-12-18 29-09

Speaker  

2  297  2’22

3  287  2’19

4  356  2’12

5  392  2’40

6  336  2’02 exposure to dogs or other livestocks in early age can help to reduce the chance of getting allergies or asthma and to become healthier. This findings are very interesting and need to explore more.

7   829  5’40         

cherry6891

末班末班~~~  原来是23环啦  明天早起

Speaker:As the city Austin growing into a big city the traffic problem appear and cause daily life trouble , some people want to leave the big city

7 5:08 the subtle distortion light may help the scientist to reveal the secrets about the earliest moment in the universe’s formation

--the measurement of B modes from gravitation lensing is an important step in the quest to measure inflationary B modes

yinghua9122

O(∩_∩)O谢谢楼主ppx
按照惯例，还是先占座~~~~
Time 2  1'48
内容不是关于绿色闪电的，是关于太阳粒子的，对吧？ 前几期看过的，忘了具体是哪期了。
Time 3  3'13
Europa's south pole erupts water vapor.
Time 4 2'30
Scientists compare Europa with Enceladus, and think that they are not only similar in the looks.
Time 5 3'01
If you have a dog in your house, it will give your a higher ability to fight allergies. Scientists have done experiments on the mice, an research have been done on the children, yes, it does.
Time 6 2'16
Tell us the interior mechanism of pets can help people defeat allergies. Dust from dog affects the gut bacterica, and gut bacterica take in charge of bodies, of couse, it can help us fight allergies or other epidemics.

苏错

最近混乱事情太多，先占座~~~

Speed:

Time2:0’53

Time3:1’37

Time4:1’53

Time5:1’43

Time6:1’53

Obstacle:5’12