Dolphins(海豚) live in a dark underwater world. It's often impossible to see each other or anything else around them, so sound plays an important role in their survival. To communicate with each other, dolphins produce all kinds of sounds.

    Only other dolphins understand what the sounds mean. Scientists haven't uncovered their secret communication, except for one kind of whistle. It might last less than a second, but this whistle is a big deal. Why? Because these whistles are actually names of dolphins - and every dolphin has one. Scientists call these sounds a “signature whistle.” When other dolphins hear the whistle, they know which dolphin is calling.

    Dolphins often hunt by themselves but still need to stay connected to the group. Since they can't always see each other, dolphins use their signature whistles to check in with other dolphins hundreds of yards away. “In coastal areas, dolphins exchange whistles even when they're a third of a mile apart,” says Greg Campbell, who studies animals. That means dolphins shout out to group members that might be nearly five football fields away.

    What's amazing is who names the baby dolphin. Not the mother. Not an auntie dolphin or another group member. Scientists believe the baby dolphin itself comes up with the signature whistle. Like human babies, a baby dolphin plays with sounds throughout its first year. While testing its sound skills, a baby dolphin is doing something amazing. It's creating or figuring out its signature whistle. How or why it chooses its signature whistle is not clear. Studies show that most of the time the signature whistle is nothing like its mother's or group members' whistles.

    When the baby dolphin is about a year old, its signature whistle is set. It repeats it often so the other dolphins learn to recognize it.

    Deciphering(破译) dolphin names is just the beginning of figuring out what dolphins communicate about. Do they chat about sharks? Discuss the tides? Maybe they even have a name for people. Someday scientists are to decipher the rest of dolphins' communication.

    They may be teenagers, but 17-year-old Brittany Bull and 16-year-old Sesam Mngqengqiswa have grand ambitions(雄心) — to launch Africa's first private satellite (卫星) into space. They are part of a team of high school girls from Cape Town, South Africa, who have designed and built equipment for a satellite that will orbit over the earth's poles scanning Africa's surface.

    Once in space, the satellite will collect information on agriculture, and food security within the continent. Using the data/we can try to determine and predict (预测) the problems Africa will be facing in the future”, explains Bull, a student at Pelican Park High School.“Where our food is growing, where we can plant more trees and vegetation and also how we can monitor remote areas,” she says. “We have a lot of forest fires and floods but we don't always get out there in time.'' Information received twice a day will go towards disaster prevention.

    It's part of a project by South Africa's Meta Economic Development Organization (MEDO) working with Morehead State University in the US.

The girls (14 in total) are being trained by satellite engineers from Cape Peninsula University of Technology, in an effort to encourage more African women into STEM (science, technology, engineering, mathematics).

    Scheduled to launch in May 2017, if successful, it will make MEDO the first private company in Africa to build a satellite and send it into orbit.

    Mngqengqiswa comes from a single parent household. Her mother is a domestic worker. By becoming a space engineer or astronaut, the teenager hopes to make her mother proud. “Discovering space and seeing the Earth's atmosphere, it's not something many black Africans have been able to do, or get the opportunity to look at I want to see and experience these things for myself,” says Mngqengqiswa.

    Her team mate Bull agrees, “I want to show to fellow girls that we don't need to sit around or limit ourselves. Any career is possible-even aerospace.”

    We've all experienced that feeling that comes when your phone makes a sound to tell you that its battery level is low. It often comes at the worst times – when you're out on a trip and don't have a charger, or when you're expecting an important phone call.

    Indeed, this feeling is so common that South Korean electronics manufacturer LG has given it a name: low battery anxiety.

    According to a survey of 2,000 US adults conducted by the company last year, 90 percent of respondents said that they panic if their battery level reaches 20 percent or lower.

    And last month, UK telecommunications service provider 02 found that around 15.5 million Britons live in “constant fear” of their mobile phones running out of power, according to a survey by the company.

    “The problem is not about being unable to make calls, but is rooted in the fact that smartphones are now where we store digital memories,” noted the Daily Mail.

    However, battery worries don't just affect smartphone lovers. Many owners of electric vehicles also suffer from so-called “range anxiety”. This refers to the concern that the vehicle may not make it to its destination before the power runs out.

    Meanwhile, it isn't just low power that people worry about. A study carried out by South Korea's Sungkyunkwan University and China's City University of Hong Kong found that many of us also worry about not having constant access to our phone.

    This condition is known as nomophobia, short for “no mobile phone phobia（恐惧症）”. Symptoms include feeling uncomfortable when access to one's phone isn't possible, being unable to turn off your phone, and constantly topping up the battery to make sure it never dies.

    So, why do so many people treat their smartphone with such importance? The underlying reason may be that they keep us connected to the people around us, and if we're unable to use our phone, we feel like we're cut off from our social life.

    With products with bigger batteries being released all the time though - such as Xiaomi's Mi Max smartphone range or Tesla's Model S cars – battery anxiety may hopefully soon be a thing of the past.

    Last year, around Labor Day, I read a “Happy Ad” in our local newspaper. There was a lady in a local nursing home for the aged, who was celebrating her 90th birthday and her family wanted everyone to know about it. It said that if you wanted to drop her a line, here was her address. So I did. I found a birthday card and dropped her a short note, wishing her a happy birthday.

    A week or so later, someone knocked at my front door. I opened the door and found a middle-aged man standing on my doorstep. He introduced himself as the son of this woman to whom I had sent the card. He explained that he just wanted to drop by in person and thank me for sending such a nice card to his mom. Apparently, like many older folks, she did not receive much mail and was quite excited to receive mine. I just didn't know what to say. I told him it was my pleasure and that I hoped his mom had enjoyed her birthday.

    That year, I did not send out any Christmas cards, except to this lovely old lady in the nursing home. I just told her that I was thinking about her and hoped that she had a nice holiday. I sent her a holiday card and also a couple of notes in between. I just thought she might like to have someone write to her, to get some mails.

    She passed away a couple of months ago. I never met this lady, but I did keep her and her family in my thoughts. I dropped them a line of sympathy. I hope that my few little notes were enough to brighten a couple of her days here on earth.

    Have you ever found yourself in this situation: You hear a song you used to sing when you were a child – a bit of nostalgia(怀旧) or "blast from the past," as we say. But it is not a distant childhood memory. The words come back to you as clearly as when you sang them all those years ago.

    Researchers at the University of Edinburgh studied the relationship between music and remembering a foreign language. They found that remembering words in a song was the best way to remember even one of the most difficult languages.

    Here is what they did. Researchers took 60 adults and randomly divided them into three groups of 20. Then they gave the groups three different types of "listen-and-repeat" learning conditions. Researchers had one group simply speak the words. They had the second group speak the words to a rhythm, or beat. And they asked the third group to sing the words.

    All three groups studied words from the Hungarian language for 15 minutes. Then they took part in a series of language tests to see what they remembered.

    Why Hungarian, you ask? Researchers said they chose Hungarian because not many people know the language. It does not share any roots with Germanic or Romance languages, such as Italian or Spanish. After the tests were over, the singers came out on top. The people who learned these new Hungarian words by singing them showed a higher overall performance. They did the best in four out of five of the tests. They also performed two times better than those who simply learned the words by speaking them.

    Dr. Katie Overy says singing could lead to new ways to learn a foreign language. The brain likes to remember things when they are contained in a catchy 3, or memorable 4, tune 5.

    Dr. Ludke said the findings could help those who struggle to learn foreign languages. On the University of Edinburgh's website Dr. Ludke writes, "This study provides the first experimental evidence that a listen-and-repeat singing method can support foreign language learning, and opens the door for future research in this area."

    Here's an idea whose time has come: A flu shot that doesn't require an actual shot.

    For the first time, researchers have tested a flu vaccine patch(疫苗贴) in a human clinical trial and found that it delivered as much protection as a traditional injection(注射) with a needle. Doctors and public health experts have high hopes that it will increase the number of people who get immunized(免疫的) against the flu.

    Seasonal flu is responsible for up to half a million deaths around the world each year according to the World Health Organization. A team led by Georgia Tech engineer Mark Prausnitz has come up with an alternative method that uses "microneedles". These tiny needles are so small that 100 of them, arranged in order on a patch, can fit under your finger. Yet they're big enough to hold vaccine for three types of flu.

    None of the study volunteers had serious side effects. The groups that got patches had mild skin reactions that were not seen in the regular needle group, while the volunteers in the regular needle group were more likely to experience pain. Overall, 70 percent of the volunteers who got vaccine patches said they'd rather use them again than get a traditional flu shot. The study authors declared it a success on all fronts.

    The biggest beneficiaries could be people in low and middle-income countries, where flu vaccines are hard to come by. Reducing pain is nice, but other benefits—the patch costs less, is easier to transport, doesn't require refrigeration, can be self-administered and doesn't cause waste of needles—are even better.

    "Microneedle Patches have the potential to become ideal candidates for vaccination programs," wrote Katja Hoschler and Maria Zambon of Public Health England.