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发表于 2013-12-31 22:15:29
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Part II:Speed
【Time 2】
Article 2
French Fries on Jupiter
Today in questions no one has ever asked: What would french fries taste like if you made them on Jupiter? Luckily, the European Space Agency is on the case. Hoping that studying deep frying in different gravitational conditions will help them improve space food for future astronauts, scientists chopped potatoes into thin sticks and deep fried them in extra-virgin olive oil, one side at a time, in a spinning centrifuge that created conditions of up to nine times Earth’s gravity. Higher gravity levels significantly increased the heat transfer between the hot oil and the potato, shortening frying time and resulting in thick, crispy crusts, the team reports next month in Food Research International. In fact, the scientists may have discovered the ideal gravitational condition for creating crunchy fries: The crust reached its maximum thickness when the potato was fried at three times Earth’s gravity; any further increase in gravity levels did not improve the fry’s crispiness. But before you patent your idea for a hypergravity deep fryer, here’s the bad news: The bottoms of the fries were insulated from the oil by a layer of water vapor rushing out of the potato’s pores, resulting in a soggy-bottomed fry no matter what the gravity level. Perhaps the team’s upcoming experiments with deep frying in microgravity will finally create the perfect space fry.
Source:
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http://news.sciencemag.org/physics/2013/12/scienceshot-french-fries-jupiter
【Time 3】
Article 3
Nuts in pregnancy may decrease allergy risk in kids
Result runs counter to past studies
Women who eat plenty of nuts during pregnancy might reduce their children’s chances of developing a nut allergy.
Physician A. Lindsay Frazier of the Dana-Farber/Harvard Cancer Center in Boston and colleagues analyzed health data on 8,205 people born from 1990 to 1994, 140 of whom developed a nut allergy.
Children of nonallergic women who had consumed five or more servings of nuts per week during pregnancy were 31 percent as likely to be diagnosed with a nut allergy as those born to nonallergic moms who ate less than one serving a week. Kids born to women who consumed one to four servings of nuts a week during gestation were about half as likely to be allergic to nuts as the offspring of moms who had largely avoided them.
Appearing online December 23 in JAMA Pediatrics, the study looked at both peanuts and tree nuts.
The new work runs counter to previous research. The authors acknowledge that the observed effect could be explained by other factors. The women who ate more nuts tended to pursue a healthier diet in general, which might somehow affect allergy risk, and were more likely to introduce nuts into their children’s diets earlier than women who avoided nuts.
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Source:
https://www.sciencenews.org/article/nuts-pregnancy-may-decrease-allergy-risk-kids
【Time 4】
Article 4
Caterpillar’s Bad Breath Scares Off Predators
The foul-breathed tobacco hornworm (Manduca sexta) may not get many dates, but the odor keeps predators at bay, a new study says.
The key to the hornworm’s halitosis is nicotine, a toxin it ingests while eating its favorite meal of tobacco leaves. New experiments show that the hornworm repurposes the nicotine, moving it from the gut to the hemolymph, the fluid that fills its circulatory system. The hornworm then excretes the excess nicotine in the hemolymph when it exhales. (Learn more about bugs.)
Wolf spiders and other predators that eat the hornworm don’t have its defenses against nicotine and find the breath repulsive—and potentially poisonous, noted study leader Ian Baldwin, an ecologist at the Max Planck Institute for Chemical Ecology in Germany.
Although plenty of animals are known to have bad breath—”ever kissed a camel?” Baldwin quipped—this is the first discovery of halitosis advertising an animal’s potential toxicity, he said.
Dangerous Nicotine
Millions of smokers worldwide know nicotine—the main ingredient of cigarettes—but the chemical’s main role is as a chemical defense in tobacco plants.
Nicotine targets the neuromuscular junction—the place where nerve cells meet muscles—in animals. So when an animal eats a plant containing nicotine, its ability to breathe and move is significantly affected.
“This is why nicotine is such a great defense for plants: it poisons everything that uses muscles to move, and since plants don’t have nerves or muscles, it doesn’t poison the plant,” said Baldwin, whose study was published December 30 in the journal Proceedings of the National Academy of Sciences.
But the tobacco hornworm is a mysterious exception. As its name suggests, the caterpillar regularly dines on nicotine-containing plants, yet doesn’t seem to suffer any ill effects.
Baldwin and colleagues were investigating how the hornworms worked their chemical magic when they stumbled upon the importance of the hornworm’s bad breath.
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【Time 5】
Plant Defenses
When the researchers looked more closely at the hornworms, they found that the expression of a gut gene known as CYP6B46 increased after the worms ate tobacco leaves. This hinted that CYP6B46 was likely involved in the hornworm’s defenses against nicotine. (Also see “Woolly Bear Caterpillars Self-Medicate—A Bug First.”)
The next task for Baldwin and colleagues was to figure out exactly what this gene did. So they grew three sets of nicotine plants to look at the function of CYP6B46. One set was engineered to contain unusually low levels of nicotine. The second contained plants that had been grown to produce a small chemical that would thwart CYP6B46 from working. The third set of plants was a control group.
The researchers then let the tobacco hornworms feed on each set of plants and measured how many insects disappeared each night due to predation. The hornworms feeding on the nicotine-deficient tobacco were eaten more than the hornworms in the control plants and the hornworms in the plants that blocked CYP6B46.
This suggested the gene is key to the insects’ defense, but the scientists still needed to know how it works. More analysis revealed that CYP6B46 transfers ingested nicotine from the insect’s stomach to the hemolymph, where the insect breathes it out.
So, without a functional CYP6B46 gene, the hornworms exhaled less nicotine, making them more vulnerable to predators.
Now, if you’ll excuse me, I’m feeling the overwhelming need to brush my teeth.
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Source:
http://newswatch.nationalgeographic.com/2013/12/30/caterpillars-bad-breath-scares-off-predators/
【Time 6】
Article 5
Last chance to stream 'Titanic,' 'Top Gun' on Netflix
(CNN) -- If you're planning to stay home New Year's Day and stream classic movies on Netflix, you may be out of luck.
More than 80 movies and a handful of TV shows -- including "Titanic," "Top Gun" and some seasons of "Saturday Night Live" -- will no longer be available for streaming through the site as of Wednesday, according to a post on Reddit.
It was not clear who posted the list, but a search on Netflix for many of the titles reveals that they will indeed expire Wednesday for Netflix's nearly 40 million streaming subscribers. The company's DVD customers -- it has about 7 million in the U.S. -- may still order the discs in the mail.
A spokesperson for Netflix told CNN that the company routinely adds and deletes titles from its streaming service due to licensing contracts.
The list of streaming movies due to expire includes such favorites as "Being John Malkovich," "Braveheart," "Do the Right Thing," "Eternal Sunshine of the Spotless Mind," "Flashdance," "Roman Holiday," "Platoon" and "War Games."
(It also includes "Breakin' 2: Electric Boogaloo" and "Killer Klowns From Outer Space.")
Among the TV shows being purged from Netflix's streaming menu: the original "Dark Shadows," "Mr Bean" and "The Kids in the Hall."
A number of new titles also will become available for streaming on Netflix at or near the first of the year, including "Jack Reacher," "The Talented Mr. Ripley," "Hansel & Gretel: Witch Hunters" and seasons 5-8 of "Dexter," the spokesperson said.
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Source:
http://edition.cnn.com/2013/12/30/tech/web/netflix-streaming-purge/index.html
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