How fit are your teeth? Are you lazy about brushing them? Never fear: An inventor is on the case. An electric toothbrush senses how long and how well you brush, and it lets you track your performance on your phone.

    The Kolibree toothbrush was exhibited at the International Consumer Electronics Show in Las Vegas this week. It senses how it is moved and can send the information to an Android phone or iPhone via a Bluetooth wireless connection.

    The toothbrush will be able to teach you to brush right (don't forget the insides of the teeth!) and make sure you're brushing long enough. “It's kind of like having a dentist actually watch your brushing on a day-to-day basis,” says Thomas Serval, the French inventor.

    The toothbrush will also be able to talk to other applications on your phone, so developers could, for instance, create a game controlled by your toothbrush. You could score points for beating monsters among your teeth. “We try to make it smart but also  fun,” Several says.

    Serval says he was inspired by his experience as a father. He would come home from work and ask his kids if they had brushed their teeth. They said “yes,” but Serval would find their toothbrush heads dry. He decided he needed a brush that really told him how well his children brushed.

    The company says the Kolibree will go on sale this summer, for $99 to $199, developing on features. The U.S. is the first target market.

    Serval says that one day, it'll be possible to replace the brush on the handle with a brushing unit that also has a camera. The camera can even examine holes in your teeth while you brush.

    There was good news last week for people who struggle to get eight hours of sleep a night: they may not need so much shut-eye after all.

    Researchers from UCLA and elsewhere looked at sleep habits of remote hunter-gatherers in Tanzania, Namibia and Bolivia — groups with pre-industrial lifestyles whose sleep patterns are believed to reflect those of ancient humans. The researchers found that, on average, members of each group sleep a bit less than six and a half hours a night.

    The study, published in the academic journal Current Biology, indicates that “natural” sleep is less than eight hours a night and that modern society's numerous electronic distractions (分心) aren't necessarily to blame for people getting just six or seven hours of sleep.

    “The story that often gets out is that if you sleep for less than seven hours, you're going to die early,” he told me. “That's not true.”

    Yet Americans are addicted to getting more sleep — and on turning to medical shortcuts to help them.

    According to the Centers for Disease Control, as many as 70 million U.S. adults suffer from sleep disorders or sleeplessness. Only a third of Americans get the government's recommended seven to nine hours of sleep a night.

    About 9 million American adults use sleeping pills to help get a good night's rest, the CDC found. Siegel said the number of people relying on medicines “has gone up rather rapidly since then.”

    Industry consulting firm Global Data estimates that worldwide sales for sleeplessness medicines will run about $1.4 billion next year and reach $1.8 billion by 2023, recovering from lower sales in recent years because of cheaper generics(仿制药) hitting the market.

    Dr. Roy Artal, a sleep specialist in West Los Angeles, said it's understandable that busy people in today's go-go world would turn to medicines to speed up the sleep process. But all they're doing is building a reliance on powerful drugs for relatively little improvement.

    “There's no magic pill that makes us sleep when we want and wake up when we want,” Artal said. “The effects of sleeping pills tend to be modest.”

    He and other experts say the answer to sleeplessness isn't to be found in a pill bottle. It's in what's called “sleep hygiene (保健).”

    A massive winter storm is expected to begin hitting Massachusetts tonight, dumping up to a foot or more of snow in some areas, while whipping the coast with powerful winds and driving rains, forecasters predict.

    “It's got a little bit of everything,” William Babecock, a meteologist（气象学家）at the National Weather Service in Taunton, said of the post-Christmas storm that brought snowstorm conditions to the Ohio Valley before heading east with its mixed bag of snow, sleet, and rain.

     State Highway Administrator Frank De Paola said more than 4,000 states and snowplows（扫雪车）and salt spreaders were ready to make the roads safer for holiday travelers.

    “MassDOT will be fully staffed and will be ready to handle this,” De Paola said, nothing that the storm, which should bring snow to most of the state except the Cape and Island before turning into rain tomorrow, is Massachusetts' first significant snow storm of this winter season.

    “There have been events where we have had pretty much freezing, icing concerns, which we have treated with chemicals.But this is the first big event that will call for plowing,” he said.

     A high wind watch has been issued for southeastern Massachusetts, including Cape Cod, Forecasters say the wind could reach 60 mph, possibly bringing down power lines.

    In Worcester, some were busy for severer by buying rock salt,shovels and windshield wash,Barrows Hardware president Brain Barrow said.He called the volume（总量）of customers at his Webster Street store very steady on Wednesday morning, “You do get that supermarket effect for sure,”he said of shoppers stocking supplies before a storm.

     There were no flight delays or cancellations at Logan International Airport in Boston as of day,” Right now, everything's running normally.” airport spokesman Richard Walsh said.But Walsh said as the day progressed, travelers should contact their airlines directly to check the status of their flights.

    Dr. Sasaki knew the first-night effect probably has something to do with how humans evolved.

    The puzzle was what benefit would be gained from it when performance might be affected the following day. She also knew from previous work conducted on birds and dolphins that these animals put half of their brains to sleep at a time so that they can rest while remaining alert enough to avoid predators (捕食者). This led her to wonder if people might be doing the same thing. To take a closer look, her team studied 35 healthy people as they slept in the unfamiliar environment of the university's Department of Psychological Sciences. The participants each slept in the department for two nights and were carefully monitored with techniques that looked at the activity of their brains. Dr. Sasaki found, as expected, the participants slept less well on their first night than they did on their second, taking more than twice as long to fall asleep and sleeping less overall. During deep sleep, the participants' brains behaved in a similar manner seen in birds and dolphins. On the first night only, the left hemispheres (半球) of their brains did not sleep nearly as deeply as their right hemispheres did.

    Curious if the left hemispheres were indeed remaining awake to process information detected in the surrounding environment, Dr. Sasaki re-ran the experiment while presenting the sleeping participants with a mix of regularly timed beeps (蜂鸣声) of the same tone and irregular beeps of a different tone during the night. She worked out that, if the left hemisphere was staying alert to keep guard in a strange environment, then it would react to the irregular beeps by stirring people from sleep and would ignore the regularly timed ones. This is precisely what she found.

    Over the centuries the French have lost a number of famous battles with the British. However, they've always felt superior in the kitchen. France has for centuries had a reputation for cooking excellence, and Britain for some of the worst cooking in the world. But according to a recent survey, that reputation may no longer reflect reality.

    In the survey, 71% of the Britons said they cook at home every day, while only 59% of the French said they cook daily. British home cooks spend more time cooking each week and also produce a greater variety of dishes than French home cooks.

    The reaction in London was predictably enthusiastic. British food has greatly improved since the 1990s. Once upon a time, the menu for many family meals would have been roast beef, potatoes and over-cooked vegetables, but not now. Home cooks are experimenting with the huge range of ingredients now available in British supermarkets and are preparing all kinds of new dishes, using the cookbooks that sell millions of copies every year. As a result, there's much more diversity in British food now, compared to French food, which tends to be very traditional.

    Some French people say that the survey did not show the whole picture. They agree that during the week French women don't cook as much as they used to because most of them work and don't have much time. They tend to buy ready-made or frozen dishes, but many of them make up for it on the weekend. There's also a difference between Paris and the countryside. It's true that people in Paris don't cook much, but elsewhere, cooking is still at the heart of daily life.

    For many French people, opinions about British food have not changed. When Bernard Blier, the food editor at a magazine, was asked about British food, he replied: "I don't go out of my way to try it. It is not very refined. You can say that I'm not a fan at all."

Yosemite is a national park in California. It is very beautiful and big. The park includes more than 760,000 acres in the California Mountains. Most of the park is wilderness.

The part of Yosemite that everyone likes is Yosemite Valley. It is a tiny valley that is 7 miles long and less than 1 mile wide. It has tall rock walls and streams that splash down in waterfalls. More than two million visitors come to the valley each year.

One ranger (守护人) says the number of visitors is more than the land can handle. The valley has 4,500 camping spots. It has a hotel that can hold 4, 000 families. This is still not enough to handle all of the visitors. The valley has grown so big that it has a lot of traffic and crime.

A worker says the park is trying to keep the beauty of the park and let everyone visit. Some areas have been fenced off from people and planted with seeds to try to keep them beautiful.

A former worker thinks Yosemite should get more money to take better care of the park. He would also like to teach people what the park service is trying to do.

Some people are trying to save Yosemite Valley. A plan has been made to get rid of some buildings. There will be fewer cars allowed inside the park. More buses will help get people around.