爱上海419论坛|阿拉爱上海同城|上海后花园论坛|夜上海419论坛|上海419龙凤

It’s hard not to compliment kids on certain things. When my little girls fancy themselves up in tutus, which is every single time we leave the house, people tell them how pretty they are. I know these folks’ intentions are good, but an abundance of compliments on clothes and looks sends messages I’d rather my girls didn’t absorb at ages 2 and 4. Or ever, for that matter.

Our words, often spoken casually and without much thought, can have a big influence on little kids’ views of themselves and their behaviors. That’s very clear from two new studies on children who were praised for being smart.

The studies, conducted in China on children ages 3 and 5, suggest that directly telling kids they’re smart, or that other people think they’re intelligent, makes them more likely to cheat to win a game.

In the first study, published September 12 in Psychological Science, 150 3-year-olds and 150 5-year-olds played a card guessing game. An experimenter hid a card behind a barrier and the children had to guess whether the card’s number was greater or less than six. In some early rounds of the game, a researcher told some of the children, “You are so smart.” Others were told, “You did very well this time.” Still others weren’t praised at all.

Just before the kids guessed the final card in the game, the experimenter left the room, but not before reminding the children not to peek. A video camera monitored the kids as they sat alone.

The children who had been praised for being smart were more likely to peek, either by walking around or leaning over the barrier, than the children in the other two groups, the researchers found. Among 3-year-olds who had been praised for their ability (“You did very well this time.”) or not praised at all, about 40 percent cheated. But the share of cheaters jumped to about 60 percent among the 3-year-olds who had been praised as smart. Similar, but slightly lower, numbers were seen for the 5-year-olds.

In another paper, published July 12 in Developmental Science, the same group of researchers tested whether having a reputation for smarts would have an effect on cheating. At the beginning of a similar card game played with 3- and 5-year-old Chinese children, researchers told some of the kids that they had a reputation for being smart. Other kids were told they had a reputation for cleanliness, while a third group was told nothing about their reputation. The same phenomenon emerged: Kids told they had a reputation for smarts were more likely than the other children to peek at the cards.
The kids who cheated probably felt more pressure to live up to their smart reputation, and that pressure may promote winning at any cost, says study coauthor Gail Heyman. She’s a psychologist at the University of California, San Diego and a visiting professor at Zhejiang Normal University in Jinhua, China. Other issues might be at play, too, she says, “such as giving children a feeling of superiority that gives them a sense that they are above the rules.”

Previous research has suggested that praising kids for their smarts can backfire in a different way: It might sap their motivation and performance.

Heyman was surprised to see that children as young as 3 shifted their behavior based on the researchers’ comments. “I didn’t think it was worth testing children this age, who have such a vague understanding of what it means to be smart,” she says. But even in these young children, words seemed to have a powerful effect.

The results, and other similar work, suggest that parents might want to curb the impulse to tell their children how smart they are. Instead, Heyman suggests, keep praise specific: “You did a nice job on the project,” or “I like the solution you came up with.” Likewise, comments that focus on the process are good choices: “How did you figure that out?” and “Isn’t it fun to struggle with a hard problem like that?”

It’s unrealistic to expect parents — and everyone else who comes into contact with children — to always come up with the “right” compliment. But I do think it’s worth paying attention to the way we talk with our kids, and what we want them to learn about themselves. These studies have been a good reminder for me that comments made to my kids — by anyone — matter, perhaps more than I know.

Discoveries about the molecular ups and downs of fruit flies’ daily lives have won Jeffrey C. Hall, Michael Rosbash and Michael W. Young the Nobel Prize in physiology or medicine.

These three Americans were honored October 2 by the Nobel Assembly at the Karolinska Institute in Stockholm for their work in discovering important gears in the circadian clocks of animals. The trio will equally split the 9 million Swedish kronor prize — each taking home the equivalent of $367,000.
The researchers did their work in fruit flies. But “an awful lot of what was subsequently found out in the fruit flies turns out also to be true and of huge relevance to humans,” says John O’Neill, a circadian cell biologist at the MRC Laboratory of Molecular Biology in Cambridge, England. Mammals, humans included, have circadian clocks that work with the same logic and many of the same gears found in fruit flies, say Jennifer Loros and Jay Dunlap, geneticists at the Geisel School of Medicine at Dartmouth College.
Circadian clocks are networks of genes and proteins that govern daily rhythms and cycles such as sleep, the release of hormones, the rise and fall of body temperature and blood pressure, as well as other body processes. Circadian rhythms help organisms, including humans, anticipate and adapt to cyclic changes of light, dark and temperature caused by Earth’s rotation. When circadian rhythms are thrown out of whack, jet lag results. Shift workers and people with chronic sleep deprivation experience long-term jet lag that has been linked to serious health consequences including cancer, diabetes, heart disease, obesity and depression.
Before the laureates did their work, other scientists had established that plants and animals have circadian rhythms. In 1971, Seymour Benzer and Ronald Konopka (both now deceased and ineligible for the Nobel Prize) found that fruit flies with mutations in a single gene called period had disrupted circadian rhythms, which caused the flies to move around at different times of day than normal.

“But then people got stuck,” says chronobiologist Erik Herzog of Washington University in St. Louis. “We couldn’t figure out what that gene was or how that gene worked.”
At Brandeis University in Waltham, Mass., Hall, a geneticist, teamed up with molecular biologist Rosbash to identify the period gene at the molecular level in 1984. Young of the Rockefeller University in New York City simultaneously deciphered the gene’s DNA makeup. “In the beginning, we didn’t even know the other group was working on it, until we all showed up at a conference together and discovered we were working on the same thing,” says Young. “We said, ‘Well, let’s forge ahead. Best of luck.’”
It wasn’t immediately apparent how the gene regulated fruit fly activity. In 1990, Hall and Rosbash determined that levels of period’s messenger RNA — an intermediate step between DNA and protein — fell as levels of period’s protein, called PER, rose. That finding indicated that PER protein shuts down its own gene’s activity.

A clock, however, isn’t composed of just one gear, Young says. He discovered in 1994 another gene called timeless. That gene’s protein, called TIM, works with PER to drive the clock. Young also discovered other circadian clockworks, including doubletime and its protein DBT, which set the clock’s pace. Rosbash and Hall discovered yet more gears and the two groups competed and collaborated with each other. “This whole thing would not have turned out nearly as nicely if we’d been the only ones working on it, or they had,” Young says.

Since those discoveries, researchers have found that nearly every cell in the body contains a circadian clock, and almost every gene follows circadian rhythms in at least one type of cell. Some genes may have rhythm in the liver, but not the skin cells, for instance. “It’s normal to oscillate,” Herzog says.
Trouble arises when those clocks get out of sync with each other, says neuroscientist Joseph Takahashi at the University of Texas Southwestern Medical Center in Dallas. For instance, genes such as cMyc and p53 help control cell growth and division. Scientists now know they are governed, in part, by the circadian clock. Disrupting the circadian clock’s smooth running could lead to cancer-promoting mistakes.

But while bad timing might lead to diseases, there’s also a potential upside. Scientists have also realized that giving drugs at the right time might make them more effective, Herzog says.

Rosbash joked during a news conference that his own circadian rhythms had been disrupted by the Nobel committee’s early morning phone call. When he heard the news that he’d won the prize, “I was shocked, breathless really. Literally. My wife said, ‘Start breathing,’” he told an interviewer from the Nobel committee.

Young’s sleep was untroubled by the call from Sweden. His home phone is the kitchen, and he didn’t hear it ring, so the committee was unable to reach him before making the announcement. “The rest of the world knew, but I didn’t,” he says. Rockefeller University president Richard Lifton called him on his cell phone and shared the news, throwing Young’s timing off, too. “This really did take me surprise,” Young said during a news conference. “I had trouble even putting my shoes on this morning. I’d go pick up the shoes and realize I needed the socks. And then ‘I should put my pants on first.’”

A new insect-inspired tiny robot that can move between air and water is a lightweight.

Weighing the same as about six grains of rice, it is the lightest robot that can fly, swim and launch itself from water, an international team of researchers reports October 25 in Science Robotics. The bot is about 1,000 times lighter than other previously developed aerial-aquatic robots. In the future, this kind of aquatic flier could be used to perform search-and-rescue operations, sample water quality or simply explore by air or sea.
To hover, the bot flaps its translucent wings 220 to 300 times per second, somewhat faster than a housefly. Once submerged, the tiny robot surfaces by slowly flapping its wings at about nine beats per second to maintain stability underwater.

For the tricky water-to-air transition, the bot does some chemistry. After water has collected inside the machine’s central container, the bot uses a device to split water into hydrogen and oxygen gas. As the chamber fills with gas, the buoyancy lifts the vehicle high enough to hoist the wings out of the water. An onboard “sparker” then creates a miniature explosion that sends the bot rocketing about 37 centimeters — roughly the average length of a men’s shoe box — into the air. Microscopic holes at the top of the chamber release excess pressure, preventing a loss of robot limbs.
Still, the design needs work: The machine doesn’t land well, and it can only pierce the water’s surface with the help of soap, which lowers the surface tension. More importantly, the experiment points to the possibilities of incorporating different forms of locomotion into a single robot, says study coauthor Robert Wood, a bioengineer at Harvard University.

Emma Watson, Jake Gyllenhaal, journalist Fiona Bruce and Barack Obama all walk into a sheep pen. No, this isn’t the beginning of a baaa-d joke.

By training sheep using pictures of these celebrities, researchers from the University of Cambridge discovered that the animals are able to recognize familiar faces from 2-D images. Given a choice, the sheep picked the familiar celebrity’s face over an unfamiliar face the majority of the time, the researchers report November 8 in Royal Society Open Science.
Even when a celeb’s face was slightly tilted rather than face-on, the sheep still picked the image more often than not. That means the sheep were not just memorizing images, demonstrating for the first time that sheep have advanced face-recognition capabilities similar to those of humans and other primates, say neurobiologist Jennifer Morton and her colleagues.

Sheep have been known to pick out pictures of individuals in their flock, and even familiar handlers (SN: 10/6/12, p. 20). But it’s been unclear whether the skill was real recognition or simple memorization. Sheep now join other animals, including horses, dogs, rhesus macaques and mockingbirds, that are able to distinguish between individuals of other species.
Morton and her colleagues released eight sheep one-by-one into a pen outfitted with two computer screens. A celebrity’s face would appear on one screen, while a different image appeared on the other. First, the team familiarized the sheep with the celebrities’ faces by showing the faces opposite a black screen or random objects. Picking the celebrity earned a sheep a food-pellet reward.
Next, researchers paired a celebrity mug, like Gyllenhaal’s now-familiar face, with an unfamiliar person. By the end of this experiment, the sheep chose a familiar celebrity’s face over a stranger’s face about 79 percent of the time on average.

To see if the sheep were just memorizing shapes, researchers did the same test, but with pictures in which the celebs’ heads were tilted right or left. The sheep didn’t do as well but still passed, recognizing the celebrities about 67 percent of the time on average — a drop in performance comparable to that seen in humans performing the same task.

In a final test, the sheep had to choose between a picture of one of their handlers’ faces and an unfamiliar face. On her first try, one sheep appeared taken aback by the new face in the mix. She did a double take of both faces before ultimately choosing her handler. Since the handler cares for the sheep daily, the animals were familiar with her — although they had never seen a 2-D photo of her face. Recognizing a person that is familiar from 3-D life requires “complex image processing,” the authors say, because the sheep must translate their memory of the person to a 2-D picture.

Brad Duchaine, a brain scientist at Dartmouth College, doesn’t find the sheep’s ability surprising. “My guess is that the ability of sheep to recognize human faces is a by-product of selection to discriminate between different sheep faces,” he says. “Either the human face is similar enough to the sheep face that [it] activates the sheep face-processing system, or human-face recognition relies on more general-purpose recognition systems.”

Et tu, antibody? In humans, dengue can be more severe the second time around. Now, a study implicates an immune system treachery as the culprit.

The study suggests that the amount of anti-dengue antibodies a person has matters. In a 12-year study of Nicaraguan children, low levels of dengue antibodies left over in the blood from a prior infection increased the risk of getting a life-threatening form of the disease the next time around, researchers report online November 2 in Science.

Four related viruses cause dengue. The theory that antibodies protective against one type of dengue can collude with a different type of the virus to make a second infection worse was proposed in the 1960s. Such antibody-dependent enhancement has been shown in cells and lab animals. But “there’s been this controversy for five decades about, does this antibody-dependent enhancement really happen in dengue” in humans, says coauthor Eva Harris, a viral immunologist at the University of California, Berkeley’s School of Public Health. “And this says, yes, it does.”

About 2.5 billion people live where there is a risk of dengue infection. The virus infects 50 million to 100 million people every year, the World Health Organization estimates, but many cases go unreported. Infection with the mosquito-transmitted virus often leads to no symptoms, but can cause fever, joint and muscle pain and other flulike symptoms. The most severe form, which affects about half a million people annually, can include internal bleeding, respiratory distress or organ failure, and may be fatal.
Getting sick with one of the four virus types can protect against a future infection of the same type. But in some cases, the theory goes, leftover antibodies from the first illness can actually help the second infection invade cells, increasing the risk of severe dengue disease.

“This study provides support for this idea that antibodies under certain conditions can be bad and actually cause severe disease when people are infected with dengue,” says viral immunologist Sujan Shresta of the La Jolla Institute for Allergy and Immunology in California. The next step, she says, is to learn more about the antibodies involved and see whether the findings hold up in other populations.

From 2004 to 2016, Harris and her colleagues studied more than 6,500 children aged 2 to 14 in Managua, Nicaragua. The researchers took blood samples each year, at a time when the kids were healthy, and assessed their antibody levels. The scientists also monitored which kids developed dengue and how severe the disease was.

An analysis showed that kids with a specific low range of anti-dengue antibodies had around a 7½ times higher risk of developing the most severe form of the disease than those who had either no antibodies or a high amount. The team’s test couldn’t tell what kind of dengue antibodies each child had. Harris and colleagues are now working on characterizing the antibodies measured in their test, to learn what makes them protective or harmful.

The new study supports the theory of antibody-dependent enhancement in humans, says Anna Durbin, an infectious diseases physician at Johns Hopkins Bloomberg School of Public Health. But she also argues that the risk of developing severe disease depends on the quality of the antibody — that is, how potent it is — as much as, or more than, the quantity. “A number in and of itself doesn’t tell you a whole lot.”

In the scientific version of her obituary, Dolly the Sheep was reported to have suffered from severe arthritis in her knees. The finding and Dolly’s early death from an infection led many researchers to think that cloning might cause animals to age prematurely.

But new X-rays of Dolly’s skeleton and those of other cloned sheep and Dolly’s naturally conceived daughter Bonnie indicate that the world’s first cloned mammal had the joints of normal sheep of her age. Just like other sheep, Dolly had a little bit of arthritis in her hips, knees and elbows, developmental biologist Kevin Sinclair of the University of Nottingham in England and colleagues report November 23 in Scientific Reports.
The researchers decided to reexamine Dolly’s remains after finding that her cloned “sisters” have aged normally and didn’t have massive arthritis (SN: 8/20/16, p. 6). No formal records of Dolly’s original arthritis exams were kept, so Sinclair and colleagues got Dolly’s and Bonnie’s skeletons and those of two other cloned sheep, Megan and Morag, from the National Museums Scotland in Edinburgh. Megan and Bonnie were both older than Dolly at the time of their deaths and had more bone damage than Dolly did. Morag died younger and had less damage.
Dolly’s arthritis levels were similar to those of naturally conceived sheep her age, indicating that cloning wasn’t to blame. “If there were a direct link with cloning and osteoarthritis, we would have expected to find a lot worse, and it would be more extensive and have a different distribution than what we’re finding in ordinary sheep,” says study coauthor Sandra Corr, a veterinary orthopedic specialist at the University of Glasgow in Scotland.
Dolly’s slightly creaky joints may have stemmed from giving birth to six lambs, including Bonnie. Pregnancy is a risk factor for arthritis in sheep.

Once billed as “the most beautiful woman in the world,” actress Hedy Lamarr is often remembered for Golden Age Hollywood hits like Samson and Delilah. But Lamarr was gifted with more than just a face for film; she had a mind for science.

A new documentary, Bombshell: The Hedy Lamarr Story, spotlights Lamarr’s lesser-known legacy as an inventor. The film explores how the pretty veneer that Lamarr shrewdly used to advance her acting career ultimately trapped her in a life she found emotionally isolating and intellectually unfulfilling.
Lamarr, born in Vienna in 1914, first earned notoriety for a nude scene in a 1933 Czech-Austrian film. Determined to rise above that cinematic scarlet letter, Lamarr fled her unhappy first marriage and sailed to New York in 1937. En route, she charmed film mogul Louis B. Mayer into signing her. Stateside, she became a Hollywood icon by day and an inventor by night.
Lamarr’s interest in gadgetry began in childhood, though she never pursued an engineering education. Her most influential brainchild was a method of covert radio communication called frequency hopping, which involves sending a message over many different frequencies, jumping between channels in an order known only to the sender and receiver. So if an adversary tried to jam the signal on a certain channel, it would be intercepted for only a moment.

During World War II, Lamarr partnered with composer George Antheil to design a frequency-hopping device for steering antisubmarine torpedoes. The pair got a patent, but the U.S. Navy didn’t take the invention seriously. “The Navy basically told her, ‘You know, you’d be helping the war a lot more, little lady, if you got out and sold war bonds rather than sat around trying to invent,’ ” biographer Richard Rhodes says in the film. Ultimately, the film suggests, Lamarr’s bombshell image and the sexism of the day stifled her inventing ambitions. Yet, frequency hopping paved the way for some of today’s wireless technologies.

Throughout Bombshell, animated sketches illustrate Lamarr’s inventions, but the film doesn’t dig deep into the science. The primary focus is the tension between Lamarr’s love of invention and her Hollywood image. With commentary from family and historians, as well as old interviews with Lamarr, Bombshell paints a sympathetic portrait of a woman troubled by her superficial reputation and yearning for recognition of her scientific intellect.

NEW ORLEANS — Saturn’s mighty rings cast a long shadow on the gas giant — and not just in visible light.

Final observations from the Cassini spacecraft show that the rings block the sunlight that charges particles in Saturn’s atmosphere. The rings may even be raining charged water particles onto the planet, researchers report online December 11 in Science and at the fall meeting of the American Geophysical Union.

In the months before plunging into Saturn’s atmosphere in September (SN Online: 9/15/17), the Cassini spacecraft made a series of dives between the gas giant and its iconic rings (SN Online: 4/21/17). Some of those orbits took the spacecraft directly into Saturn’s ionosphere, a layer of charged particles in the upper atmosphere. The charged particles are mostly the result of ultraviolet radiation from the sun separating electrons from atoms.
Jan-Erik Wahlund of the Swedish Institute of Space Physics in Uppsala and Ann Persoon of the University of Iowa in Iowa City and their colleagues examined data from 11 of Cassini’s dives through the rings. The researchers found a lower density of charged particles in the regions associated with the ring shadows than elsewhere in the ionosphere. That finding suggests the rings block ultraviolet light, the team concludes.

Blocked sunlight can’t explain everything surprising about the ionosphere, though. The ionosphere was more variable than the researchers expected, with its electron density sometimes changing by more than an order of magnitude from one Cassini orbit to the next.

Charged water particles chipped off of the rings could periodically splash into the ionosphere and sop up the free electrons, the researchers suggest. This idea, known as “ring rain,” was proposed in the 1980s (SN: 8/9/86, p. 84) but has still never been observed directly.

OXON HILL, Md. — Astronomers may soon know for sure if Europa is spouting off. After finding signs that Jupiter’s icy moon emits repeating plumes of water near its southern pole, astronomers using the Hubble Space Telescope hope to detect more evidence of the geysers.

“The statistical significance is starting to look pretty good,” astronomer William Sparks of the Space Telescope Science Institute in Baltimore says. He presented preliminary results on the hunt for the plumes at a meeting of the American Astronomical Society on January 9.
Sparks’ team started observing Europa on January 5, hoping to catch it passing in front of Jupiter 30 times before September. Hubble can detect active plumes silhouetted against background light from Jupiter. If the plume repeats as often as it seems to, “it’s essentially a certainty we’ll see it again if it’s real,” Sparks said.

Europa probably hosts a vast saltwater ocean buried under a thick icy shell. In 2012, astronomers using Hubble spotted high concentrations of hydrogen and oxygen over Europa’s southern hemisphere — signs that Europa was spitting water into space (SN: 1/25/14, p. 6). Later efforts to find those signs using the same technique yielded nothing.

But using Jupiter as a backdrop for the plumes, Sparks and his colleagues spotted several eruptions (SN Online: 9/26/16) — once in March 2014, again in February 2016 and possibly also in March 2017, Sparks said.

Story continues below images
Maps of Europa’s heat and ionosphere made by the Galileo spacecraft in the 1990s show the plumes’ location was warmer than the surrounding ice. It also had an unusually high concentration of charged particles, perhaps the result of water splitting into hydrogen and oxygen. Both observations support the idea that some ocean is escaping at that spot.

“If it’s a coincidence, it’s a hell of a coincidence,” Sparks says.

It’s still too early to pack your bags for TRAPPIST-1. But two new studies probe the likely compositions of the seven Earth-sized worlds orbiting the cool, dim star, and some are looking better and better as places to live (SN: 3/18/17, p. 6).

New mass measurements suggest that the septet probably have rocky surfaces and possibly thin atmospheres, researchers report February 5 in Astronomy & Astrophysics. For at least three of the planets, those atmospheres don’t appear to be too hot for life, many of these same researchers conclude February 5 in Nature Astronomy.
TRAPPIST-1 is about 40 light-years from Earth, and four of its planets lie within or near the habitable zone, the range where temperatures can sustain liquid water. That makes these worlds tempting targets in the search for extraterrestrial life (SN: 12/23/17, p. 25)

One clue to potential habitability is a planet’s mass — something not precisely nailed down in previous measurements of the TRAPPIST-1 worlds. Mass helps determine a planet’s density, which in turn provides clues to its makeup. High density could indicate that a planet doesn’t have an atmosphere. Low density could indicate that a planet is shrouded in a puffy, hydrogen-rich atmosphere that would cause a runaway greenhouse effect.

Using a new computer technique that accounts for the planets’ gravitational tugs on each other, astronomer Simon Grimm of the University of Bern in Switzerland and his colleagues calculated the seven planets’ masses with five to eight times better precision than before. Those measurements suggest that the innermost planet probably has a thick, viscous atmosphere like Venus, Grimm says. The other six, which may be covered in ice or oceans, may have more life-friendly atmospheres. The fourth planet from the star has the same density as Earth and receives the same amount of radiation from its star as Earth, Grimm’s team reports in Astronomy & Astrophysics.

“This is really the cool thing: We have one planet which is very, very similar to the Earth,” Grimm says. “That’s really nice.”
Having an atmosphere could suggest habitability, but not if it’s too hot. So using the Hubble Space Telescope, MIT astronomer Julien de Wit and his colleagues, including some members from Grimm’s team, observed the four middle planets as they passed in front of the star. The team was looking for a signature in near-infrared wavelengths of light filtering through planets’ atmospheres. That would have indicated that the atmospheres were full of heat-trapping hydrogen.

In four different observations, Hubble saw no sign of hydrogen-rich atmospheres around three of the worlds, de Wit and colleagues report in Nature Astronomy. “We ruled out one of the scenarios in which it would have been uninhabitable,” de Wit says.

The new observations don’t necessarily mean the planets have atmospheres, much less ones that are good for life, says planetary scientist Stephen Kane of the University of California, Riverside. It’s still possible that the star’s radiation blew the planets’ atmospheres away earlier in their histories. “That’s something which is still on the table,” he says. “This is a really important piece of that puzzle, but there are many, many pieces.”

Finishing the puzzle may have to wait for the James Webb Space Telescope, scheduled to launch in 2019, which will be powerful enough to figure out all the components of the planets’ atmospheres — if they exist.