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.

    By trying to tickle(挠痒痒) rats and recording how their nerve cells respond, Shimpei Ishiyama and his adviser are discovering a mystery that has puzzled thinkers since Aristotle expected that humans, given their thin skin and unique ability to laugh, were the only ticklish animals.

    It turns out that Aristotle was wrong. In their study published on Thursday, Ishiyama and his adviser Michael Brecht found that rats squeaked and jumped with pleasure when tickled on their backs and bellies. These signs of joy changed according to their moods. And for the first time, they discovered a special group of nerve cells. These nerve cells made this feeling so powerful that it causes an individual being tickled to lose control.

    To make sure that he had indeed found a place in the brain where tickling was processed, Ishiyama then stimulated that area with electrical currents. The rats began to jump like rabbits and sing like birds.

    “It's truly ground-breaking,” said Jeffrey Burgdorf, a neuroscientist at Northwestern University who reviewed the paper. “It takes the study of emotion to a new level.”

    Burgdorf has played a central role in our understanding of animal tickling. He was part of a team that first noticed, in the late 1990s, that rats made special noises when they were experiencing social pleasure. Others had already noted that rats repeatedly made short and high sounds during meals. But the lab where Burgdorf worked noticed that they emitted similar sounds while playing. And so one day, the senior scientist in the lab said, “Let's go and tickle some rats.” They quickly found that those cries of pleasure doubled.

    “The authors have been very adventurous,” said Daniel O'Connor, a neuroscientist at Johns Hopkins University who studies touch. To him, that finding was very surprising.

    “Why does the world literally feel different when you are stressed out?” he said. “This is the first step towards answering that question. It gives us a way to approach it with experimental rigor(严谨).”

    Four years ago, we asked ourselves: what if we could create a shopping experience with no waiting in lines and no checkout? Or could we create a physical store where customers could simply take what they want and go? Our answer to those questions is Amazon Go, where you could experience the idea of "just walk out shopping".

    Amazon Go is a new kind of store with no checkout required. We created the world's most advanced shopping technology, so you never have to wait in line. With our "just walk out shopping" experience, simply use the Amazon Go app to enter the store, take the products you want, and go! No lines, no checkout.

    Our checkout-free shopping experience is made possible by the same types of technologies used in self-driving cars: computer vision, sensor fusion, and deep learning. Our "just walk out technology" automatically detects when products are taken from or returned to the shelves and keeps track of them in your virtual cart（虚拟购物车）. When you've done shopping, you can just leave the store. Shortly after, we'll charge your Amazon account and send you a receipt(收据).

    We offer delicious ready-to-eat breakfast, lunch, dinner, and snack options made fresh every day by our on-site chefs and favorite local kitchens and bakeries. Our selection of foodstuff ranges from bread and milk to cheeses and locally made chocolates. You'll find well-known brands we love, plus special finds we're excited to introduce to customers. For a quick home-cooked dinner, pick up one of our chef-designed Amazon Meal Kits, and you can make a meal for two in about 30 minutes.

    Our 1,800-square-foot shopping space is conveniently compact(紧凑的), so busy customers can get in and out fast. It is located at 2131, 7th Ave, Seattle, WA, on the corner of 7th Avenue and Blanchard Street. All you need is an Amazon account, a supported smartphone, and the free Amazon Go app.

    Amazon Go is currently only open to Amazon employees in our testing program, and will be open to the public soon.

    During an earthquake, you should know what to do. If the earthquake strikes while you're inside a house, you should lie on the floor under a strong table or other furniture. If there is no furniture, you can cover your head with your arms and keep still in the corner of the room. You should keep away from windows, glass walls, or anything that can fall.

    If you are in bed, hold firmly onto your bed and make use of a pillow to safeguard your head. You may use a doorway but only when it is close to you. It should also be considered whether it is strong enough to deal with the load.

    If you are running out, do not use lifts, even if they work. Electricity may go out at any time. Many injuries happen when people try to rush out. This means you ought to stay in your house or perhaps wherever you are.

    When you stay outdoors, you should stay far from buildings, power wires or lights. You should be in the open until the quake stops. Remember that many earthquake deaths outside the house come from falling-apart walls, flying glass and other falling things.

    If an earthquake strikes and you are driving, you should pull up to the side of the highway and stop as quickly as possible. You ought not to stop under trees, buildings or energy wires. Don't stop in the middle of the street as it could trouble others.

    When trapped, you shouldn't move. Your mouth should be covered with a piece of clothing or a handkerchief. This is because it is possible for you to breathe in some dust. Do not shout whenever possible. You should only shout in the end to get help from rescuers.

After years of teachers asking for the right answers, students aren't used to someone asking for the wrong ones. Students' failure tends to create mental burden that negatively affects learning. Lifting the burden requires us to face failure bravely and encourage students to accept it as a natural part of getting educated. While educators have to make sure that students have the right content and support to avoid long-term failure, it is just as important to accept mistakes as a normal part of education.

Sadly, our culture is so focused on success or perfection that students generally aren't taught about failure. To fill the gap, I share with students a Samuel Beckett quote "Ever tried. Ever failed. No matter. Try again. Fail again. Fail better". It suggests one becomes better after each failure. I also play a video on game designed by Extra Credits, which shows people can quickly declare their ways as a failure if they don't work out and then learn from. them to move on. Both the quote and the video can help students get a more positive attitude towards failure.

Teachers can help students accept failure better. In her piece "5-Minute Film Festival: Freedom to Fail Forward", Edutopia author Amy Erin Borovoy had a set of videos-and articles on the subject of failure. Borovoy reminds readers that "a true thinker learns as much from failure as from success." Taking these short videos as monthly or weekly reminders can, be a great way to start "how have we failed and what have we learned" discussions with students.

Teachers can actually use a technique called "Effective Failure" to teach about failure at any time. In my writing class, I often have students volunteer to pick out the worst writing of their own. This lets writers deepen their understanding of why a sentence, word choice, or paragraph construction has failed, and it inspires a sincere interest in better writing. This makes failure work well in class.

Also, remember that students are not the only ones who can learn from their mistakes. As those who teach students, we should do that too.

The best places to see giant pandas are, of course, in Chengdu, hometown of giant pandas. But there are zoos/parks in other China cities where you can see giant pandas if you can't get to Chengdu.

Dujiangyan Panda Base

● Location: Dujiangyan Prefecture, 67 km (41 mi) or 

● 1.5 hours from Chengdu

● Pandas: about 20

● Activities: panda viewing, and panda keeper program

● Suitable for: those who want a less-crowded panda base or to join in a one-day volunteer program

● Time needed: half a day

Dujiangyan Panda Base focuses on breeding, wilderness training, and releasing pandas into the wild.

Only 1.5 hours from Chengdu, it is the most easily-accessible panda base offering a panda keeper program.

Wolong Panda Base

● Location: 121 km (175 mi) west of Chengdu, 3 hours' driving

● Pandas: about30

● Activities: seeing pandas, panda keeper program, hiking in wild panda habitat

● Best for: taking part in a volunteer program in a peaceful environment

● Time needed: 2 days

Compared with Dujiangyan, Wolong Panda Base is much further away from Chengdu. Thus, it is less frequented by visitors. Besides, Wolong National Nature Reserve is considered to be the real hometown of wild pandas.

Chongqing Zoo

● Location: Chongqing City, conveniently on subway line 2

● Pandas: about 16

● Activities: Seeing pandas only

● Time needed: 2 hours

● Best for: travelers who visit Chongqing or take a Yangtze Cruise

Chongqing Zoo boasts 16 pandas, which is second to Chengdu Giant Panda Breeding Center among the city zoos. Located in the "Mountain City", Chongqing Zoo is built on the mountain slopes. The panda house utilizes the mountainside and includes a rock cave. So, you have to climb up a little for a panda visit there.