With the clicking of walking sticks and determined steps, a long line of walking group along the winding road is a fantastic sight. Almost each of the walkers is using some kind of fitness tracker. A few Fitbits, some Xiaomi wrist bands (手环), a couple of phone apps and some other pedometers (计步器) — and all, they say, are counting their steps.

    Fitness trackers are in. Sales figures for 2016 released by Internet Data Center (IDC) indicated 25% market growth compared to the previous year, with Fitbit taking the lion's share, followed by the brand Xiaomi.

    However, the wearables market has had a rollercoaster ride in recent months. Jawbone, once a popular fitness tracker brand, announced that it is leaving the consumer market. Microsoft has removed its Fitness Band on its online store although it is still available on retail (零售) giant Amazon. Fitbit remains a key brand name at the heart of the fitness tracker revolution. But it is recently reported to be cutting down on workers, and its founder James Park said it experienced “softer than expected” sales recently.

    Counting steps is probably the most common use of wearable devices (可穿戴设备), but recently experts have questioned whether the golden goal of walking 10,000 steps a day is actually worthwhile, and a US study concluded that health trackers did not aid weight loss.

Analyst Ben Wood from CCS Insight used to wear a fitness tracker on either wrist. Now, however, his concern is about users'experience — these devices don't tell you anything new after a while. There are also battery problems and many of the older and cheaper varieties aren't waterproof (防水的).

    Bats are the only mammals(哺乳动物) that can fly a great distance, but they have another ability. Many bats live a very long time for an animal of their size. European researchers are studying bats to understand why they lives0 long. They hope to make discoveries aimed at fighting the aging process in human beings.

    Last week, the group of scientists said they had identified important biological qualities in some bat species. The group studied bat chromosomes(染色体), a line of genes found in the nucleus(细胞核) of cells. The scientists were most interested in structures connected to the ends of the chromosomes. They are called telomeres(端粒), which protect the ends of chromosomes and shorten each time a cell divides. Scientists believe this shortening process causes cells to breakdown. They say this is what causes aging.

    The European researchers studied 493 bats from four bat species. The group used information that had been gathered over more than 60 years. Of these animals ，the greater mouse-eared bat generally lived the longest, an average of 37 years. The scientists said this and a related species, which are grouped together under the name Myotis, had telomeres that did not shorten with age. Another Myotis bat holds the record for oldest age, reaching 41years. The scientists' findings suggest that these bats cells have the ability to maintain and repair their telomeres. This, they said, helps guard against the aging process.

    Based on its body size, a bat like the greater mouse-eared bat would be expected to live four years. But, these mammals have been found to live nearly 10 times longer than that. The scientists found that only 19 species of mammals live longer than humans when their body size is considered. Eighteen of these are bats.

    Orthopedic pillows are not just like any other ordinary pillow. These products are specially made to fulfill a specific function.

    People buy orthopedic pillows for several reasons. Sometimes people buy this type of pillow because their doctor has specifically recommended them to do so as part of a treatment and management plan for neck, back, or bone problems. In recent years, people have become more aware of the science behind orthopedic pillows, which accounts for the increase in the popularity of these pillows. There has been a lot of available orthopedic pillow information for anyone interested. The science behind these pillows has also advanced significantly over the years, which means that orthopedic pillows are now more effective and useful than ever.

    Orthopedic pillows help you maintain the right gesture. While traditional pillows may be very comfortable, they do not necessarily promote the proper gesture as you sleep, which is proved to be important for your health. It also helps you avoid waking up with a host of body aches and pains. Among the most common causes of back and neck pains is sleeping without adequate support. Orthopedic pillows can provide you with the necessary support that will keep these kinds of body pains away. The pillow is specifically designed to conform to the natural contours (轮廓) of your body, thus ensuring that your skeletal structure is kept in proper alignment (直线) throughout the night and that no part of your body is subjected to too much pressure, which leads to pain.

    Of course, it is understandable that you may find an orthopedic pillow a bit uncomfortable the first time you use it, but that is true with any new experience. The materials used in manufacturing these pillows are ideal for the kind of sleep that you are looking for.

    Just like any product in the market, there is a disadvantage to an orthopedic pillow as well. They are usually more expensive than traditional pillows. But, if you treat the purchase as an investment on your health, it may be a lot easier for you to part with the cash.

Earth Day Photo Contest

    A picture is worth a thousand words! Enter the TFK photo contest and show us: Why is Earth Day important to our planet?

    To enter the contest online, visit timeforkids.com and get details below.

    TIME

    ●The contest begins on January 9, 2017.

    ●The contest ends on April 20, 2017.

    INSTRUCTIONS

    ●An original and previously unpublished photograph that answers the Earth Day question "Why is Earth Day important to our planet?" and that was photographed by the entrant (参赛者) between June 1, 2016, and April 20, 2017.

    ●A brief description describing the picture: what is happening, where the photo was taken, the date the photo was taken and why the entrant chose to enter this image.

    ●Entrant's first name only; entrant's e-mail address; and parent's, teacher's or guardian's e-mail address. Limit one work per person. Sponsors are not responsible for lost, late, or incomplete entries, or entries not received for any reason. Works belong to sponsors, and none will be acknowledged (承认) or returned.

    ●By entering, the entrant ensures that the work is first made and has not been published in any medium or won an award.

    ELIGIBILITY

    Open to the elementary school students at age 8-13 at the time of entry in the USA.

    WINNERS' LIST AND PRIZES

    Judges will select 10 semifinalists (半决赛选手) from whom one grand prize winner and nine finalists will be chosen. The grand prize winner will receive a digital camera—approximate retail (零售) value: $300. The photograph entry of the grand prize winner will be published in the April 22 Earth Day issue of TIME For Kids. The photograph entries of all semifinalists will be published in the gallery of timeforkids.com. Winners will be informed by e-mail, and must respond within five days.

    You're probably used to the regular upgrades in our cell-phone networks. There was 2G, which came along in 199l, replaced with 3G in 2001, followed by 4G in 2009. Now we're hearing about the coming of 5G.

    But 5G is a much bigger leap than before. 5G, of course, is much faster than 4G in the real world and a 5G phone in a 5G city will enjoy Internet speeds between 9 and 20 times as fast. The arrival of 5G also means enormous leaps forward in capacity－so much that every cell-phone plan will offer cheap, truly unlimited Internet access. "The consequences of that are huge," says Sherif Hanna, Qualcomm's director of 5G marketing. For example, apps will no longer degrade (降低) your video quality or postpone downloading when you're out of Wi-Fi range. In fact, you'll probably prefer to do your downloads when you're on cellular (使用流量) because 5G will be much faster than whatever service you've got at home or work.

    "However, not everyone is excited by the 5G development. The new standard gets its speed partly by using existing transmission(传输) frequencies more efficiently and partly by using the millimeter wave range. That's a big, juicy line of radio frequencies that are currently underused because millimeter wave is really hard to use," Hanna says.

    These frequencies are much higher than anything we've used for the cellular, which means they can offer unbelievable speed－but at the cost of range. Millimeter wave cellular towers have to be about 500 feet apart. Cell carriers not only will have to upgrade all their cell transceivers (called small cells) but will install(安装) a lot more of them as well.

    That's why the millimeter wave flavor of 5G, the superfast coverage, will be available only in densely populated cities such as New York and San Francisco. In suburban and rural areas, 5G will bring a speedup of "only" nine times faster.

Even though they're not the most exciting things in the world, plants have fascinated us ever since the days of early humans. They may not do any tricks or greet us when we come home at night like a dog would, but that doesn't mean they're any less interesting than animals.

However, just when we thought we knew everything we could about them, a recent study found that plants may possess a secret ability that's gone unnoticed all this time. According to the study by Australian biologist Monica Gagliano, published in the journal Oecologia, plants may be able to hear sounds.

To come to this conclusion, Gagliano and her team planted pea seedlings in a pair of different Y-shaped pots with two arms. The first pot's arms led to fresh water, while the other's led to either dry soil or a sealed plastic tube containing flowing water.

Naturally, the first pot's seedlings grew toward the water. What's surprising, however, is that the second pot's seedlings grew toward the sealed water supply and not the soil.

They just knew the water was there, even if the only thing to detect was the sound of it flowing inside the pipe, Gagliano told Scientific American. Gagliano believes that plants are able to use their leaves to detect sound waves, which make tiny vibrations (振动) as they're produced.

This could explain why so many people believe that singing or playing music to their plants helps them grow.

I had a plant that I used to wash the leaves once a week and sing to it, plant lover Heather Goodall told BBC News. It grew from being about 2 feet tall to 7 feet tall in just a couple of years.

So, does this mean we should start treating our plants like pets? Not necessarily, although perhaps it does mean we should give them more respect. I would like to see plants acknowledged more as the amazing, interesting, exotic living beings they are, and less as a mere source of human nutrition, Fatima Cvrckova, a scientist at Charles University in the Czech Republic, told BBC News.