C

    The animal kingdom lost a beloved friend when poachers（偷猎者）in Kenya killed the world famous elephant named Satao solely for his ivory（象牙）, experts say.

    Satao was considered by some to be the largest and oldest elephant left in Africa. His tusks having grown long enough to reach the ground. Wandering around Kenya's Tsavo National Park, he was easily recognizable（可辨认的）by staff and visitors. Sadly, despite conservation efforts, he was killed on May 30, his body identified by park staff on June 2. His head was severely damaged and there were two holes left where his great tusks had

    “There is no doubt that Satao is dead, killed by an ivory poacher's poisoned arrow to feed the seemingly greedy demand for ivory in far off countries,” wrote Richard Moller of The Tsavo Trust. “A great life lost so that someone far away can have a trinket（饰品）.

    Satao isn't the first elephant—and far from the last—to pay the ivory price. Just last month, Mountain Bull, another Kenyan elephant, was killed by poachers.

    Kenya Wildlife Service（KWS）says 97 elephants and 20 rhinos have been killed this year, but others say the real numbers are much higher.

    The national park in which Satao lived is roughly 386 square miles—a massive land for already thinly-stretched resources to cover. Reports indicate that Satao had started to migrate towards the park's border-areas known by conservationists（野生保护人士）to be highly active for poaching.

    In the late 1960s, more than 275,000 elephants lived in Kenya. Now, that number has dropped to around 38,000, and continues to fall fast.

    “If Satao's death can cause the focus on what's actually happening here in terms of poaching, then he won't have died in vain,” said nature documentarian Mark Decble, according to The Dodo.

    Whether in the home or the workplace, social robots are going to become more common in the next few years. Social robots are about to bring technology to the everyday world in a more humanized way, said Cynthia Breazeal, chief scientist at the robot company Jibo.

    While household robots today do the normal housework, social robots will be much more like partners than tools. For example, these robots will be able to tell when someone is happy or sad. This allows them to respond more properly to the user.

    The Jibo robot, arranged to ship later this year, is designed to be a personalized assistant. You can talk to the robot, ask it questions, and make requests for it to perform different tasks. The robot doesn't just give general answers to questions; it responds based on what it learns about each person in the household. It can do things such as reminding an elderly family member to take medicine or taking family photos.

    Social robots are not just finding their way into the home. They have potential(潜在的) applications in everything from education to health care and are already finding their way into some of these areas.

    Fellow Robots is one company bringing social robots to the market. The company's “Oshbot” robot is built to assist customers in a store, which can help the customers find items and help guide them to the product's location in the store. It can also speak different languages and make recommendations for different items based on what the customer is shopping for.

    The more interaction the robot has with humans, the more it learns. But Oshbot, like other social robots, is not aimed to replace workers, but to work together with other employees. “We have technologies to train social robots to do things not for us, but with us,” said Breazeal.

    Courses & Curriculum of the College of Arts & Sciences in Cornell

    Scientists dug up human remains from the Stonehenge dating back to about 5,000 years ago. To our surprise, people journeyed far to get to the Wessex site. These men and women potentially played a huge role in the construction of Stonehenge.

    The study, published in the journal Scientific Reports, reveals that a number of people buried at the Wessex monument originated from West Wales, which is also the source of the bluestones used in Stonehenge's early construction.

    According to a report from the University College London, scientists from Oxford and Belgium came together to analyze 25 of the burials dug in 2008. Many of them were buried around 3,000 BC, which is around the time when the bluestones were put up to form the Aubrey holes around Stonehenge. The famous stones weren't built until 500 years later. The team used chemical isotope (同位素) analysis and radiocarbon dating (放射性碳年代测定法) the study and found out that at least 10 of the 25 individuals analyzed didn't live near the Stonehenge site but in western Britain. This region includes West Wales, where the bluestones were sourced. Furthermore, the wood that was used to burn the bodies was also found to have come from different trees. Some of the pieces of trees come from trees in dense woodland, many of which are found in West Wales. Some of the individuals may have been cremated elsewhere before being buried in Stonehenge.

    The researchers suggest that these prehistoric people may have been part of the sacred site's early construction crew. They may have been the ones to transport the bluestone materials from the Preseli Mountains in West Wales. The findings are an interesting revelation, particularly since it means that there were significant interregional connections that existed as far back as 5,000 years ago. Even back then, in the Neolithic Period (新石器时代), human civilization had wide contacts and exchanges.

    After moving to the United States, immigrant groups trying to fit in tend to choose high calorie fatty foods in an attempt to appear more American, a new study finds. That's one reason why immigrants approach US levels of obesity within 15 years of moving to America.

The researchers also did an experiment that measured whether or not the threat of appearing un-American influenced respondents' food choices. After being questioned about their ability to speak English 75 percent of Asian-Americans identified a typical American food as their favorite. Only 25 percent of Asian-Americans who had not been asked if they spoke English did the same.

    When their American identity was called into question during a follow-up study, Asian-American participants also tended to choose typical American dishes, such as hamburgers and cheese sandwiches.  In that experiment, 55 Asian-Americans were asked to choose a meal from a local Asian or American restaurant. Some participants were told that only Americans could participate in the study. Those who chose the more typical American fare ended up consuming an extra 182 calories,  including 12 grams of fat and 7 grams of saturated fat (饱和脂肪).

    "People who feel like they need to prove they belong to a culture will change their habits in an attempt to fit in," said Sauna Cheryan, an author of the study and assistant professor of psychology at the University of Washington.

    "If immigrants and their children choose unhealthy American foods over healthier traditional foods across their lives, this process of fitting in could lead to poorer health." Cheryan added.

    Social pressures, the study concluded, are at the heart of the problem.  "In American society today, being American is associated with being white. Americans, who don't fit this image even if they were born here and speak English, feel that pressure to prove that they're American," said Cheryan.

You've probably heard it a dozen times by now. But here it goes again: Sleep is important. Your mental health and immune (免疫时)system are connected to your sleeping habits. So are your grades, a new study finds. Sleep accounts for nearly one-fourth of the difference among students' grades in a class. So even if you spend hours studying for a test but get too little sleep, you might still do poorly.

Typically, people's sleep schedules are messy and can not be known in advance. Professor Jeffrey Grossman of Massachusetts Institute of Technology in Cambridge wanted to see if sleep links to people's learning performance even when a study was done with people who kept such true-to-life schedules at home. So he turned to Fitbits, which can check how long people sleep and how frequently they wake up. And the researchers looked for 100 students. They focused on these students' sleep patterns in the days and weeks before exams and then compared them to these students' test scores.

"How much time a person sleeps the night. before an exam doesn't affect that person's grade," Grossman says. "A student who sleeps 7 hours every night will do better than a student who sleeps 7.5 hours one night and 6.5 hours another night."

"It's important for people to know that if their Fitbits tell them that they have terrible sleep, that may not actually be so," Michael Scullin, a sleep scientist at Baylor University says. Grossman also raises this point. Fitbit, Inc. makes this advanced tool. But it doesn't share how its tool works. This leaves a question about whether the tool is really correct when checking a student's sleep. Even so, Scullin emphasizes that there are enough data supporting ties between sleep and how well someone performs.

"Students need more sleep and less late evening use of phones and other screens. Even with after-school activities and schoolwork, they need to get enough sleep," Grossman says.