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发表于 2014-1-6 22:25:39
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Part II:Speed
Year in Review: Language learning starts before birth
by Laura Sanders 10:00am, December 23, 2013 Magazine issue: December 28, 2013
[Time 2]
Parents are usually careful to watch their language around young children. Maybe parents-to-be ought to watch what they say, too. Not only do babies slurp up language skills in the first few years of life, but new research also suggests that this precocious language learning starts in the womb.
In the later months of pregnancy, fetuses can detect and remember songs, native vowel sounds and entire words. These surprisingly sophisticated linguistic feats offer a new perspective on early learning. The results also raise the possibility of taking steps during pregnancy to help babies at risk for language problems.
Toward the end of pregnancy, sounds from the outside world can seep into a developing fetus’s brain. Young babies show a clear preference for the sounds of their mothers’ voices, familiar nursery rhymes and soothing lullabies, for instance. Four months after birth, babies who had heard “Twinkle, Twinkle Little Star” while in the womb remembered and recognized the lullaby, cognitive neuroscientist Eino Partanen of the University of Helsinki and colleagues reported October 30 in PLOS ONE. The music doesn’t need to be baby-friendly, either. An earlier study found that babies born to mothers who had been hooked on a soap opera during pregnancy stopped fussing when the theme song started.
The findings extend the boundaries of what and when fetuses can learn. “We just don’t know the limits,” says psychologist Christine Moon of Pacific Lutheran University in Tacoma, Wash., who coauthored one of the new studies.
[244 words]
[Time 3]
Moon and her colleagues found that fetuses learn to discern native vowel sounds from foreign ones. To catch babies before they had time to familiarize themselves with the outside world, the scientists studied Swedish and U.S. babies seven to 75 hours after birth. These newborns were hooked up to special pacifiers that detected sucking rates. The more sucking, the more unusual a sound was, the researchers reasoned.
Babies sucked more for foreign vowel sounds, Moon and her team reported in Acta Pædiatrica (SN: 2/9/13, p. 9), showing that the babies had grown familiar with native vowels while in the womb.
Fetal learning doesn’t stop at vowels. Fetuses grew familiar with an entire made-up word, Partanen and colleagues reported in the Proceedings of the National Academy of Sciences (SN: 10/5/13, p. 15). In the last trimester, pregnant women blasted a recording of a researcher saying a fake word. Testing the babies’ brain responses with electrodes soon after birth, a neural signature of familiarity called the mismatch response showed up in those who had heard the word during gestation. These babies’ brains showed a big neural response when a syllable in the fake word was pronounced differently, suggesting that the normal version was familiar.
Such knowledge about fetal learning could one day lead to specially designed audio tracks that could boost language skills in fetuses at risk for language impairments such as dyslexia. Carefully crafted auditory cues played during pregnancy might stimulate the growing brain in a way that aids language skills.
The new work also draws attention to the importance of the acoustical environment for a fetus. Because the fetal brain is sensitive to sounds, constant exposure to a noisy environment might be problematic. Loud, unstructured noise could mask this early language acquisition and interfere with normal brain development.
[298 words]
Source:Science News
https://www.sciencenews.org/article/year-review-language-learning-starts-birth
Year in Review: Putting kids at risks
by Nathan Seppa 6:30am, December 24, 2013
[Time 4]
The tenet that “doctor knows best” is taking a beating. U.S. parents increasingly are delaying their children’s vaccinations, basing such decisions on sources other than their pediatricians, researchers reported in 2013. Nearly half of U.S. babies born from 2004 to 2008 fell behind on at least one vaccination (SN: 2/23/13, p. 11).
Many parents cite concerns about the 23 shots babies now get in the first two years of life, says epidemiologist Jason Glanz of Kaiser Permanente in Denver. “You can see the parents’ perspective,” he says.
Vaccination schedules have been fine-tuned to protect children at a vulnerable age, doctors point out, but they can’t force the issue. Glanz and colleagues examined the records of 320,000 kids under age 2, finding that 49 percent got at least one shot more than a month late. That proportion has been rising for five years. Overall, 20 percent of kids spent more than 100 days unprotected against a disease because of late shots.
Vaccine fears arose over a decade ago when some people blamed shots for health problems, claims later shown to be unfounded. A 2013 study debunked more recent claims that vaccination can cause Guillain-Barré syndrome, a nerve-damaging disorder. A review of 3 million people in the Kaiser database showed no connection between the disorder and getting any vaccine (SN: 7/27/13, p. 16).
Putting off shots might be grounded in parents’ desire to make safe choices for their child, say University of Pennsylvania physicians Kristen Feemster and Paul Offit, writing in JAMA Pediatrics in October. But in reality, “it offers no clear benefit,” they say. Such parents may be well-meaning, but in this case doctors really may know best.
[277 words]
Source:Science News
https://www.sciencenews.org/article/year-review-putting-kids-risk
Google search fails to find any sign of time travelers
by Tom Siegfried 6:08pm, January 3, 2014
[Time 5]
Time travel is an extraordinarily popular pastime. Or at least it would be if it were possible. Evidently it isn’t, though; as Stephen Hawking once observed, we never encounter any tourists from the future.
To make his point, Hawking once held a party for time travelers from the future, but nobody came. Of course, he didn’t post the invitation until after the date of the event, in order that only people from the future would know about it.
So for the time being, time travel remains fictional. But it has been fictional for a long time. Decades before Doctor Who, H.G. Wells wrote his famous book The Time Machine (1895). More than a century and a half before that, an Irish writer named Samuel Madden published (anonymously) Memoirs of the Twentieth Century (1733). Madden declared that he had the “honor and misfortune” to be the first historian to depart from writing “the accounts of past Actions and Times” and “dar’d to enter by the help of an infallible Guide, into the dark Caverns of Futurity, and discover the Secrets of Ages yet to come.” Those secrets had been revealed to Madden by a time traveler who had appeared one night like an angel, leaving him a series of volumes containing state papers from the reign of George VI.
A little over a century later, Edgar Allan Poe, in a prose poem titled Eureka, mentioned a letter, found in a bottle, dated 2848. Its writer complained about ancient scientists’ devotion to deductive and inductive reasoning, when in fact, science “makes its most important advances … by seemingly intuitive leaps.”
So maybe there’s a flaw in Hawking’s experiment, based as it was on deductive logic. After all, it’s easy to come up with explanations for why his invitation went unnoticed. Maybe by the time that time travel is invented, everybody has forgotten about Hawking, or YouTube has gone out of business.
On the other hand, perhaps time travelers just want to keep their existence a secret. But even highly trained supersecret time travel agents might slip up occasionally and accidentally reveal their future origins. Like for instance, by typing Comet ISON into Google before that comet had even been discovered. But even if they did, who would ever know?
Well, Robert Nemiroff and Teresa Wilson of the Michigan Technological University physics department might. Comet ISON was discovered in 2012, so it is very unlikely that anyone from the present would have searched online for it, or tweeted about it, before then. Nemiroff and Wilson reasoned that searching the Internet for pre-2012 mentions of Comet ISON might turn up evidence of a time traveler.
[441 words]
[Time 6]
It’s not easy to conduct such searches, and the results can be misleading. Old web pages often contain new ads, for instance. And while it’s possible to search a site that records Google search queries, that site only reports on terms with a high search volume, so a single request for Comet ISON info would not have been recorded.
Twitter, though, can be searched comprehensively. But Nemiroff and Wilson found no evidence for any tweeting about Comet ISON before it was discovered. They tried various other searches of other databases, also without success. They also tried searching for any mention of Pope Francis before he became pope, just in case time travelers aren’t interested in astronomy. Still no luck.
But unlike Hawking, Nemiroff and Wilson do not conclude that time travelers therefore do not exist.
“Although the negative results reported here may indicate that time travelers from the future are not among us and cannot communicate with us over the modern day Internet, they are by no means proof,” Nemiroff and Wilson write in their paper.
After all, deductions about time travel are vulnerable to the flaws afflicting all deductions — such as relying on premises that might not be true. Poe’s letter writer from 2848 commented on this point. He observed that ancient logical reasoning based on deduction from “self-evident” truths, or axioms, is bogus, as there is no such thing as a self-evident truth. Even 19th century scientists should have realized that, the letter writer pointed out, as some supposedly self-evident truths (such as, “a thing cannot act where it is not”) had already been shown to be wrong.
Poe’s letter writer then commented that perhaps one “palpable truism” had in fact been identified, by a 19th century logician named Mill: “‘Ability or inability to conceive … is in no case to be received as a criterion of axiomatic truth.”
Surely, many false things have been conceived (unicorns), and many inconceivable things have turned out to be true (USA beats Soviets in ice hockey, 1980). So the ability of many writers and even scientists to conceive of time travel does not prove that it is true. But the inability of many others to conceive of time travel does not mean it is false.
[375 words]
Source:Science News
https://www.sciencenews.org/blog/context/google-search-fails-find-any-sign-time-travelers
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