Elephants might be the most well-known and well-loved animal in African wildlife. But conservation (保护) of the African elephant faces special difficulties. While the elephant population is half of what it was 40 years ago, some areas of Africa have more elephants than populated areas can support. That's why AWF scientists are studying elephant behavior, protecting habitats and finding ways for humans to live peacefully with elephants in Africa.

    Years ago, over hunting and the ivory trade were the biggest threats to elephants survival. Luckily, ivory bans (禁令), hunting rules and protected areas protect elephants from these dangers today.

    The 21st century brings a different challenge to elephant conservation —land-use. Elephants walk across borders and outside parks and other protected areas. So they often destroy crops, causing conflicts (冲突) between local farmers and these big animals.

    Successful conservation strategies (策略) must allow elephants to walk freely in their natural habitats while reducing conflicts between elephants and local people.

    AWF researchers are searching for a way to give both elephants and people the space they need. The AWF is collecting information on elephant habitats and behavior. The information they gather will help to develop the widest possible space for elephants.

    The AWF is helping elephants by protecting their habitats. And they also work with local farmers to improve their life in order to encourage them to protect rather than destroy elephants.

    Are you preparing for a big test? If so, you may want to go to play some basketball in between hitting the books. Doctors are starting to find more and more information that suggests a connection between exercise and brain development. Judy Cameron, a scientist at Oregon Health and Science University, studies brain development. According to her research, it seems that exercise can make blood vessels (血管), including those in the brain, stronger and more fully developed. Dr. Cameron is sure that this allows people who exercise to think better. As she says, “While we already know that exercise is good for the heart, exercise can actually cause physical changes in the brain.”

The effects of exercise on brain development can even be seen in babies. Babies who do activities that require a lot of movement show greater brain development than babies who are less physically active. Even a little movement can show big results. Margaret Barnes, a scientist, also believes in the importance of exercise. She thinks that many learning disabilities that children have in primary school or high school can result from a lack of movement as babies. Babies need movement that encourages and excites their five senses. They need to set up a connection between motion and memory. In this way, as they get older, children will begin to connect physical activity with higher learning,” says Margaret.

    Older people can develop their brains as well. Cornell University studied a group of seniors who have a short-term memory increase of up to 40 percent after exercising just three hours a week. The exercise does not have to be very difficult, but it does have to increase the heart rate. Also, just like the motion for babies, exercise for older people should not be too simple. Learning some new skills or actions, such as with yoga or tat- chi helps to open up memory paths in the brain that may not have been used for a long time. For most people, any type of physical activity that increases the heart rate is helpful. The main aim is to increase the brain's flow of blood. And your brain can benefit from as little as two to three hours of exercise a week.

    The pillage (掠夺) and destruction of ancient shipwrecks and sunken archaeological sites by treasure hunters seeking gold and other valuables may be illegal under the terms of an international treaty under discussion by UNESCO's 188 Member States.

    "Protecting our underwater heritage is extremely important and increasingly urgent as no site or shipwreck is now out of bounds for treasure hunters. New technologies have made deep-water wrecks easily accessible and these technologies are getting cheaper," warns Lyndel Prott.

    According to estimates by commercial salvors (寻宝者), there are some three million undiscovered shipwrecks scattered across the world's oceans. Even the figures for the known wrecks are impressive. The Northern Shipwrecks Database for example contains 65,000 ship loss records for North America alone from 1500 AD to the present. The Dictionary of Disasters at Sea by Charles Hocking (1969) lists 12,542 sailing ships and war vessels lost between 1824 and 1962.

    Then there are sunken cities such as the trading town and pirate stronghold(海盗堡垒) of Port Royal in Jamaica, which disappeared beneath the waves after an earthquake in 1692. Or the remnants of ancient civilisations, such as the Lighthouse of Alexandria in Egypt, and the Neolithic villages being discovered under the Black Sea, which some believe could help explain Noah's great flood.

    These treasures of cultural heritage are under serious threat. Technology now allows extraordinary access to the ocean depths for determined and well-financed treasure hunters. And the potential rewards are huge. In 1985, American salvor Mel Fisher discovered the wreck of the Señora de Atocha, a Spanish ship that sank off the Florida Keys in 1622 with her cargo of gold, silver and jewellery worth an estimated US $400 million.

    An archaeologist can spend ten years or more studying a ship, conserving its objects and publishing its findings. We gain an enormous amount of information and knowledge from this work. With treasure hunters, all of this is lost. This is tragic, for humanity as a whole.

    Every year, billions of kilograms of fresh produce are wasted in the United States. Meanwhile, millions of poor Americans go hungry, without access to healthy and affordable meals. Evan Lutz, CEO and founder of Hungry Harvest, was inspired to act after seeing extreme poverty in areas of Baltimore, Maryland. He wants to reduce the so—called food waste in that area. His work is to make sure no food goes to waste and no person is ever hungry in America. And he combines that goal with a love for business.

    Hungry Harvest is a business which collects and sells fruits and vegetables that most food companies will throw away. Everything doesn't grow the same way on a farm. But all that is too big or too small gets thrown out. That is why everything in a grocery store looks similar. Hungry Harvest will box those imperfect ones and deliver them to customers once a week.

    For every purchase, Hungry Harvest delivers healthy food to people in need. Hungry Harvest has recovered 300,000 pounds of produce to date and provided 100,000 pounds to those in need.

    Lutz established Hungry Harvest in 2014.Its success depends on team work. Every week on Monday or Tuesday they will decide what will go into the next week's box by calling up packing houses and wholesalers to see what they will normally throw away that week. They then place the order. The last step ls to send goods to customers.

    In January 2016,Lutz appeared on the American business competition television show "Shark Tank" and got even more than he expected: $100,000.Lutz is using the money to expand. Actually, more than six billion pounds is wasted each year due to "ugly" surface. Hungry Harvest is on the way to saving more food from going to waste and feeding hungry families.

    Running is often tiring and a lot of hard work, but nothing beats the feeling you get after finishing a long workout around the track.

    But while it's long been believed that endorphins (脑内啡）—chemicals in the body that cause happiness — are behind the so-called “runner's high”，a study suggested that there may be more to this phenomenon than we previously knew.

    According to a recent study published by a group of scientists from several German universities, a group of chemicals called endocannabinoids (内源性大麻素）may actually be responsible for this familiar great feeling.

    To test this theory, the scientists turned to mice.

    Both mice and humans release high levels of endorphins and endocannabinoids after exercise, along with many other chemicals. After exercising on running wheels, the mice seemed happy and relaxed and displayed no signs of anxiety.

    But after being given a drug to block their endorphins the change. However, when their endocannabinoids were block with a different drug, their runner's high symptoms seemed to fade.

    “The long-held notion of endorphins being responsible for the runner's high is false. Endorphins are effective pain relievers, but only when it comes to the pain in your body and muscles you feel after working out,”Patrick Lucas Austin wrote on science blog Lifchacker.

    Similar studies are yet to be carried out on humans, but it's already well known that exercise is a highly effective way to get rid of stress or anxiety.

    The UK's National Health Service even prescribes (开药方)exercise to patients who are suffering from depression.

    “Being depressed can leave you feeling low in energy, which might put you off being more active. Regular exercise can boost your mood if you have depression, and it's especially useful for people with mild to moderate (中等的）depression,” it wrote on its website.

    It seems like nothing can beat that feeling we get after a good workout, even if we don t fully understand where it comes from. At least if we're feeling down, we know that all we have to do is put on our running shoes.

    People think of cats as cute. But research published in a psychology journal calls them neurotic (神经质的) and unstable. Researchers from the University of Edinburgh in Scotland and the Bronx Zoo in New York compared the personalities of domestic house cats with those of four different types of wildcats.

    To better understand their personalities, the researchers rated a number of animals behaviors on what psychologists call the Big Five human personality traits (特征).

    Domestic house cats have similar personality structures to African lions. "It's what cats do pretty much on a daily basis, things like being anxious, being timid, being excitable, being aggressive toward humans, being aggressive toward each other, "said Max Wachtel, a Denver psychologist who didn't participate in the study. "All of those are characteristics you see in those cute little house cats, and you also see them in lions."

    If you ever thought your cat was anxious, insecure, tense, suspicious or aggressive toward you, you aren't making it up, he said. If they were bigger, they probably would consider killing you.

    But the news isn't all bad: Just like lions, house cats are also playful, excitable and impulsively funny. They just aren't very predictable. One moment cats will be enjoying bell scratches, and the next they will be biting you to make you stop.

    "It is good to understand the personality characteristics of our pets," Wachtel said "Different cats have different personalities, but as a species, there are a lot of commonalities."

    The researchers also studied personality traits of Scottish wildcats and some other animals “Across the five species we assessed, personality structure was strikingly similar and also seemed to be related to other studies' findings, such as in tigers, "the researchers wrote in their study in the November 2014 issue of the Journal of Comparative Psychology. But house cats were most like lions, potentially because they live in semi-social surroundings and lions are the most social of cats.

    “They're cute and furry, but we need to remember when we have cats as pets, we are inviting little predators into our house," Wachtel said. "Cats can be fantastic, sweet companions -until they turn on you.”