The Brown Bear

    My wife Laura and I were on the beach, with three of our children, taking pictures of shore birds near our home in Alaska when we spotted a bear. The bear was thin and small, moving aimlessly.

Just a few minutes later, I heard my daughter shouting, “Dad! The bear is right behind us!” An aggressive bear will usually rush forward to frighten away its enemy but would suddenly stop at the last minute. This one was silent and its ears pinned back— the sign (迹象) of an animal that is going in for the kill. And it was a cold April day. The bear behaved abnormally, probably because of hunger.

    I held my camera tripod (三脚架) in both hands to form a barrier as the bear rushed into me. Its huge head was level with my chest and shoulders, and the tripod stuck across its mouth. It bit down and I found myself supporting its weight. I knew I would not be able to hold it for long.

    Even so, this was a fight I had to win: I was all that stood between the bear and my family, who would stand little chance of running faster than a brown bear.

    The bear hit at the camera, cutting it off the tripod. I raised my left arm to protect my face; the beast held tightly on the tripod and pressed it into my side. My arm could not move, and I sensed that my bones were going to break.

Drawing back my free hand, I struck the bear as hard as I could for five to six times. The bear opened its mouth and I grasped its fur, trying to push it away. I was actually wrestling (扭打) with the bear at this point. Then, as suddenly as it had begun, the fight ended. The bear moved back toward the forest, before returning for another attack—- The first time I felf panic.

    Apparently satisfied that we caused no further threat, the bear moved off, destroying a fence as it went. My arm was injured, but the outcome for us could hardly have been better. I'm proud that my family reminded clear-headed when panic could have led to a very different outcome.

    An autonomous vehicle designed for making local commerce deliveries was unveiled by Nuro. The vehicle is about the height of an SW but far narrower than a typical car. The electric car features four exterior compartments (暗格) — two on each side — to hold separate deliveries. Each compartment can be tailored to a specific use, such as cooking a pizza or refrigerating a package.

    “We can use self-driving technology to deliver anything, anytime, anywhere for basically all local goods and services,” Nuro co-founder Dave Ferguson said. “Consumers used to be okay with two-week paid shipping. It became two-week free delivery, followed by one week, two days, and the same day. Now same-day delivery isn't fast enough for some customers.”

    Nuro isn't alone in building robots for local commerce deliveries. Earlier this month, Toyota, a Japanese car company, unveiled a concept vehicle that could be used for package delivery. A handful of startups — including Starship Technologies, Marble and Dispatch — are testing small robots for deliveries on sidewalks.

    Nuro's vehicle will likely face legal hurdles. Fully autonomous vehicles without a test driver aren't legal in California today, and many companies have shifted testing to states where regulators are more welcoming of autonomous vehicles, such as Arizona.

    Nuro expects to face fewer challenges because it doesn't carry passengers. Nuro's narrow size may also be helpful when navigating streets and avoiding pedestrians. The vehicle isn't equipped with any special features to communicate with pedestrians or other road users. Some companies have tested and patented solutions such as digital screens that signal the car's next move. Ferguson said his team conducted studies and found that such techniques could confuse people. Nuro believes it's better to make sure the car performs predictably, so that human drivers know what to expect from it.

    “We feel by creating this new technology that's going to enable this last mile delivery, we're going to be creating new markets and doing things that previously weren't possible,” Ferguson said. “This is not swapping out Jobs with robots. It's creating new markets. There will definitely be new employment opportunities.”

Dogs are man's best friends—they are very good for children's health. Researchers found that family pets helped to protect babies against breathing problems and infections (感染).

    A team from Kuopio University Hospital in Finland studied 397 babies born at their hospital between September 2012 and May 2015 for their first year. They found that babies who lived with a dog or a cat spent fewer weeks with ear infections, coughs or runny noses. They were also less likely to need antibiotics (抗生素) than babies in homes without a pet.

    Study author, Dr. Eija Bergroth, said dogs brought dirt and bacteria (细菌) into the home, which helped children's immune system (免疫系统) to be strong. This improved their defenses against bacteria.

    As part of the study, parents filled out weekly diaries starting when the children were nine weeks old, recording information on babies' health as well as their contact with cats and dogs. They recorded if they had fever, ear infections, coughs or running noses. They also put down whether they needed antibiotics.

    Based on those diaries, the researchers found that about a third of the children spent most of their first year with a pet dog and 24 percent in a home with a cat. And children with no dog contact at home were healthy for 65 percent of the time, compared to between 72 and 76 percent for those who did have a pet.

    The researchers also found that contact with dogs, more than cats, was tied to fewer weeks of sickness for babies.

    However, the researchers said they couldn't rule out the possibility that people who own dogs are less likely to get sick for another reason, not due to any protection offered by pets.

    We hope you've finally made your peace with Pluto being downgraded from a planet to an ice dwarf (冰矮星)，because we have some more jarring news for you : It seems your teachers may have been wrong about the number of continents on the earth, too.

    Earlier this year, scientists published a report in the journal of the Geological Society of America detailing an eighth continent called Zealandia, roughly the size of India and almost completely hid itself under the Pacific Ocean east of Australia. Covering all of New Zealand as well as several nearby islands, Zealandia likely spent the best of its above-water days as part of the supercontinent Gondwana before fragmenting off Australia and Antarctica some 80 million years ago. This lost, underwater continent is just beginning to reveal its secrets, making for one of the most promising scientific discoveries this year.

    While researchers have been aware of the 1. 9 million-square-mile mass for two decades, Zealandia has only recently become the object of serious study since the Geological Society paper argued that it fits all the criteria for a proper continent, including a continental crust (地壳)that's distinctly separate from the seabed in terms of elevation, thickness, and geology. A team of 32 scientists from 12 countries just completed their first visit to six dig sites around Zealandia, where they drilled up more than 8,000 feet of sediment cores (沉积物岩心)that will help explain the lost continent's 80-million-year history.

    Because there is no official body that formally recognizes continents, whether or not Zealandia ends up in future geography textbooks will come down to its acceptance by the scientific community at large, possibly with a little help from travelers like you.

    In a recent series of experiments at the University of California, researchers studied toddlers' thinking about winners and losers, bullies (欺凌) and victims.

    In the first experiment, toddlers (学步儿童) watched a scene in which two puppets (木偶) had conflicting goals: One was crossing a stage from right to left, and the other from left to right. The puppets met in the middle and stopped. Eventually one puppet bowed down and moved aside, letting the other one pass by. Then researchers asked the toddlers which puppet they liked. The result: 20 out of 23 toddlers picked the higher-status puppet — the one that did not bow or move aside. It seems that individuals can gain status for being dominant (占优势的) and toddlers like winners better than losers.

    But then researchers had another question: Do toddlers like winners no matter how they win? So, researchers did another experiment very similar to the one described above. But this time, the conflict ended because one puppet knocked the other down and out of the way. Now when the toddlers were asked who they liked, the results were different: Only 4 out of 23 children liked the winner.

    These data suggest that children already love a winner by the age of 21-31 months. This does not necessarily mean that the preference is inborn: 21 months is enough time to learn a lot of things. But if a preference for winners is something we learn, we appear to learn it quite early.

    Even more interesting, the preference for winners is not absolute. Children in our study did not like a winner who knocked a competitor down. This suggests that already by the age of 21-31 months, children's liking for winners is balanced with other social concerns, including perhaps a general preference for nice or helpful people over aggressive ones.

    In a time when the news is full of stories of public figures who celebrate winning at all costs, these results give us much confidence. Humans understand dominance, but we also expect strong individuals to guide, protect and help others. This feels like good news.

Some people today might be early risers because of DNA they take after Neanderthals tens of thousands of years ago, suggests new research.

When early humans migrated from Africa to Eurasia roughly 70, 000 years ago, some of them mated with Neanderthals, who had already adapted to the colder, darker climates of the north. The ripple(涟漪) effects of that inter mating still exist today：Modern humans of non-African ancestry(血统) have between 1 and 4 percent Neanderthal DNA. Some of that DNA relates to sleep more specifically, the internal body clock known as the circadian rhythm.

For the new study, researchers compared DNA from today's humans and DNA from Neanderthal fossils(化石) .In both groups, they found some of the same genetic variants involved with the circadian rhythm. And they found that modern humans who carry these variants also reported being early risers.

For Neanderthals, being "morning people" might not have been the real benefit of carrying these genes. Instead, scientists suggest, Neanderthals' DNA gave them faster, more flexible internal body clocks, which allowed them to adjust more easily to annual changes in daylight. This connection makes sense in the context of human history. When early humans moved north out of Africa, they would have experienced variable daylight hours—shorter days in the winter and longer days in the summer-for the first time. The Neanderthals' circadian rhythm genes likely helped early humans' offspring(后代) adapt to this new environment.

Notably, the findings do not prove that Neanderthal genes are responsible for the sleep habits of all early risers. Lots of different factors beyond genetics can contribute, including social and environmental influences. The study also only included DNA from a database called the U.K. Biobank-so the findings may not necessarily apply to all modern humans. Next, the research team hopes to study other genetic databases to see if the same link holds true for people of other ancestries. If the findings do apply more broadly, they may one day be useful for improving sleep in the modern world, where circadian rhythms are disturbed by night shifts and glowing smartphones.