Larry was on another of his underwater expeditions(探险)but this time, it was different. He decided to take his daughter along with him. She was only ten years old. This would be her first trip with her father on what he had always been famous for.

    Larry first began diving when he was his daughter's age. Similarly, his father had taken him along on one of his expeditions. Since then, he had never looked back. Larry started out by renting diving suits from the small diving shop just along the shore. He had hated them. They were either too big or too small. Then, there was the instructor. He gave him a short lesson before allowing him into the water with his father. He had made an exception. Larry would never have been able to go down without at least five hours of theory and another similar number of hours on practical lessons with a guide. Children his age were not even allowed to dive.

    After the first expedition, Larry's later diving adventures only got better and better. There was never a dull moment. In his black and blue suit and with an oxygen tank fastened on his back, Larry dived from boats into the middle of the ocean. Dangerous areas did not prevent him from continuing his search. Sometimes, he was limited to a cage underwater but that did not bother him. At least, he was still able to take photographs of the underwater creatures.

    Larry's first expedition without his father was in the Cayman Islands. There were numerous diving spots in the area and Larry was determined to visit all of them. Fortunately for him, a man offered to take him around the different Spots for free. Larry didn't even know what the time was, how many spots he dived into or how many photographs he had taken. The diving spots afforded such a wide array of fish and sea creatures that Larry saw more than thirty varieties of creatures.

    Larry looked at his daughter. She looked as excited as he had been when he was her age. He hoped she would be able to continue the family tradition. Already, she looked like she was much braver than had been then. This was the key to a successful underwater expedition.

    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.

    A new argument has been put forward as to whether penguins are disturbed by the presence of tourists in Antarctica.

    Previous research by scientists from Keil University in Germany monitored Adelie penguins and noted that the birds' heart rates increased dramatically at the sight of a human as far as 30 meters away. But new research using an artificial egg, which is equipped to measure heart rates, disputes this. Scientists from the Scott Polar Research Institute at Cambridge say that a slow moving human who does not approach the nest too closely, is not viewed as a threat by penguins.

    The earlier findings have been used to partly explain the 20 per cent drop in populations of certain types of penguins near tourist sites. However, tour operators have continued to insist that their activities do not adversely（不利地）affect wildlife in Antarctica, saying they encourage non-destructive behavior in tourists, and that the decline in penguin numbers is caused by other factors.

    Amanda Nimon of the Scott Polar Research Institute spent three southern hemisphere summers at Cuverville Island in Antarctica studying penguin behavior towards humans. “A nesting penguin will react very differently to a person rapidly and closely approaching the nest,” says Nimon. “First they exhibit large and prolonged heart rate changes and then they often flee the nest leaving it open for predators（掠夺者）to fly in and remove eggs or chicks.” The artificial egg, specially for the project, monitored both the parent who had been 'disturbed' when the egg was placed in the nest and the other parent as they both took it in turns to guard the nest.

    However, Boris Culik, who monitored the Adelie penguins, believes that Nimon's findings do not prove his own research invalid. He points out that species behave differently – and Nimon's work was with Gentoo penguins. Nimon and her colleagues believe that Culik's research was methodologically（方法论上）defective because the monitoring of penguins' responses needed catching the birds and fitting them with heart-rate transmitters（发射器）. Therefore, argues Nimon, it would not be surprising if they became stressed on seeing a human subsequently.

    Thirteen-year-old American Jessica Goldstone wants to be a fashion designer when she finishes school. She thinks her designs would be more exciting than clothes bought from stores. But until this month, Jessica has never touched a sewing machine(缝纫机).

    After her first class, Jessica and six other girls aged 9 to 13 said that sewing was fun, cool and challenging.

    These students at Fabrics' Sew Fun class show that the sewing machine is becoming popular again.

    "There have been a lot of teens getting excited about sewing," said a sewing company worker Donna Smith. "Some of them come from the Project Runway TV show," she said. This TV show is an exciting weekly contest to make a great fashion designer. Every week one contestant (参赛者) fails the test and has to leave the contest.

    The number of people who joined sewing class summer camps grew by 10 percent this year. That's good news for companies that make sewing machines and publish sewing magazines. The Singer Sewing Company sold nearly 3 million sewing machines in the United States last year. This is about twice as many as in 1999.

    Sewing machines have been around for more than 150 years, but they have changed a lot since your grandmother was a girl.

    Spencer Carmel started sewing lessons after getting a sewing machine for her 11^th birthday. She has sewn a lot by hand, but she wants to make more difficult things. Spencer's class recently made hats.

    Another member of the class, Kelsey Oen, 9 years old, needed time to get used to her machine, but soon she could use it well. By the end of the class, Kelsey was happy and wearing her new hat.

    Since English biologist Charles Darwin published On the Origin of Species in 1859, scientists have vastly improved their knowledge of natural history. However, a lot of information is still of the speculation, and scientists can still only make educated guesses at certain things.

    One subject that they guess about is why some 400 million years ago, animals in the sea developed limbs (肢) that allowed them to move onto and live on land.

    Recently, an idea that occurred to the US paleontologist (古生物学家) Alfred Romer a century ago became a hot topic once again.

    Romer thought that tidal (潮汐的) pools might have led to fish gaining limbs. Sea animals would have been forced into these pools by strong tides. Then, they would have been made either to adapt to their new environment close to land or die. The fittest among them grew to accomplish the transition (过渡) from sea to land.

    Romer called these earliest four-footed animals “tetrapods”. Science has always thought that this was a credible theory, but only recently has there been strong enough evidence to support it.

    Hannah Byrne is an oceanographer (海洋学家) at Uppsala University in Sweden. She announced at the 2018 Ocean Sciences Meeting in Oregon, US, that by using computer software, her team had managed to link Homer's theory to places where fossil deposits (沉积物) of the earliest tetrapods were found.

    According to the magazine Science, in 2014, Steven Balbus, a scientist at the University of Oxford in the UK, calculated that 400 million years ago, when the move from land to sea was achieved, tides were stronger than they are today. This is because the planet was 10 percent closer to the moon than it is now.

    The creatures stranded in the pools would have been under the pressure of “survival of the fittest”, explained Mattias Green, an ocean scientist at the UK's University of Bangor. As he told Science, “After a few days in these pools, you become food or you run out of food... the fish that had large limbs had an advantage because they could flip (翻转) themselves back in the water.”

    As is often the case, however, there are others who find the theory less convincing. Cambridge University's paleontologist Jennifer Clark, speaking to Nature magazine, seemed unconvinced. “It's only one of many ideas for the origin of land-based tetrapods, any or all of which may have been a part of the answer,” she said.

    As people age, the body changes in all sorts of predictable ways. Brains can slow. Wounds take longer to recover. And sleep patterns(模式) shift, too. This can come as news to many, says Michael V. Vitiello, a psychologist at the University of Washington who is expert in sleep in aging.

The most noticeable—and often most annoying—changes are how sleep and wake-up times change and sleep gets lighter, often beginning in middle age. Gone are weekend sleep to 11 a.m. and the ability to sleep through a noisy garbage truck down the block.

But not every restless night can be ignored. Studies have found that poor sleep can create a particular threat to older adults—Falls, depression and anxiety, problems with memory, and increased suicide(自杀) risk are among the effects of sleep issues in this population group that researchers have found. But scientists are still unsure why those risk connections exist.

    What is clear is the connection between good sleep and psychological well-being in older adults. A 2010 study showed us that connection when it came to sleep quality, but sleep quantity didn't show the same effects. And that, experts say, may be the key to understanding sleep as you age. If you're sleeping less, but don't feel negative effects out of bed, the changes you notice may just be normal age-related.

    Over time, Vitiello says, sleep patterns simply change. "A lot of older adults recognize that they don't sleep the same as they did when they were 18, but they can still function and they're OK. And all is well with the universe."