In one of the world's most forbidding environments, Polar bears spend !heir summers roaming (漫步) the Arctic on large pieces of floating ice. They drift(漂移) for hundreds of miles, finding mates, hunting for seals , and fatting themselves up for the winter. Without the floating ice , the world's largest bears could not survive Yet at this moment , the polar bears' Arctic habitat (栖息地) is melting away under it because of global warming.

    Over the past three decades, more than a million square miles of floating ice has disappeared Scientists predict that, if the current rate of global warming continues, most, if not all, of the bears' floating ice will be gone by 2100. As a result, the world's polar bears could face global dying out by the end of this century.

    Already, the ice on the southern edge of the polar bears' habitat is melting about three weeks earlier than in the past. The loss of those key weeks leaves the bears less time to hunt, eat and store up fat. Once the ice melts, the bears must fast for up to eight months on land until the floating ice returns. As a result of early melting, there has been a 14 percent decline in the Hudson Bay polar bear population over the past ten years- a fall clearly caused by global warming.

    Besides, a growing number of polar bears may be drowning (溺水) as they are forced to swim more often, and for longer distances, looking for ice sheets(冰原). According to a report by the US Mincrals Management Service, researchers observed four dead polar bears floating 60miles off Alaska in September of2006 and said it was likely that many other bears swimming far off shore also drowned. Scientists have concluded that the worldwide population of about 20,000polar bears is likely to become smaller by more than 30 percent in the next 35 to 50 years alone.

    I grew up with a group of pets. As a mother, I was determined to provide my daughter with the same joyful experiences. Indeed, by the time my daughter was in elementary school, our house was known as "the neighborhood zoo". Now that she is a teenager, we've reduced the number of animals in our home, but we still live with two dogs. I can't imagine life without them.

    Regardless, I have become increasingly uncomfortable with the word "pet". When I came upon the conclusion by the University of Tennessee zoologist Gordon Burghardt that the best we can do for pets is a life of "controlled deprivation (剥夺)", I wished I had never bought Lizzy, our leopard gecko(豹纹守宫). I felt a pit in my stomach when I learned that Lizzy's constant clawing at the glass wall of her tank was most likely a signal of stress. It is perhaps not surprising that she died after only two years, despite our efforts to give proper care.

    The problems with the various small creatures we put into cages and tanks are relatively clear-­cut. More challenging moral questions, in my view, arise in relation to our closest furry friends: dogs and cats. Unlike animals that must spend their entire life in a cage or that must struggle to adapt to a human environment, most cats and dogs have it pretty good. Yet it is likely that our dogs and cats may be suffering in ways we don't readily see, because even the most well meaning owner doesn't always provide what an animal needs.

    It may be hard to recognize the harmful aspects of pet keeping when all we hear is how beloved pets are and how happy they are to be in our company. Advertisements showing golden­-haired children playing with golden-­haired puppies and YouTube videos of cats doing funny things make pet keeping look ever so precious.

    Yet if we really care about animals, we ought to know animals are not toys — they are living, breathing, feeling creatures.

    Smile! It makes everyone in the room feel better because they, consciously or unconsciously, are smiling with you. Growing evidence shows that an instinct for facial mimicry(模仿) allows us to empathize with and even experience other people's feelings. If we can't mirror another person's face, it limits our ability to read and properly react to their expressions. A review of this emotional mirroring appears on February 11 in Trends in Cognitive Sciences.

    In their paper, Paula Niedenthal and Adrienne Wood, social psychologists at the University of Wisconsin, describe how people in social situations copy others' facial expressions to create emotional responses in themselves. For example, if you're with a friend who looks sad, you might "try on" that sad face yourself without realizing you're doing so. In "trying on" your friend's expression, it helps you to recognize what they're feeling by associating it with times in the past when you made that expression. Humans get this emotional meaning from facial expressions in a matter of only a few hundred milliseconds.

    "You reflect on your emotional feelings and then you generate some sort of recognition judgment, and the most important thing that results in is that you take the appropriate action—you approach the person or you avoid the person," Niedenthal says. "Your own emotional reaction to the face changes your perception of how you see the face in such a way that provides you with more information about what it means."

    A person's ability to recognize and "share" others' emotions can be prevented when they can't mimic faces. This is a common complaint for people with motor diseases, like facial paralysis(瘫痪) from a stroke, or even due to nerve damage from plastic surgery. Niedenthal notes that the same would not be true for people who suffer from paralysis from birth, because if you've never had the ability to mimic facial expressions, you will have developed compensatory ways of interpreting emotions.

    People with social disorders associated with mimicry or emotion-recognition damage, like autism(自闭症), can experience similar challenges. "There are some symptoms in autism where lack of facial mimicry may in part be due to limitation of eye contact," Niedenthal says.

    Niedenthal next wants to explore what part in the brain is functioning to help with facial expression recognition. A better understanding of that part, she says, will give us a better idea of how to treat related disorders.

    Florida is a state located in the southeastern region of the United States. It is one of the most visited states in the country and the sunshine state attracts millions of visitors each year. Are you planning a vacation to it? Here our travel guide may help you.

    La Nouba at Walt Disney World Resort

    Duration: 90 minutes

    Location: Orlando, Florida

    While you're in Orlando, spend a day at the theme parks with a Cirque du Soleil show at Downtown Disney, La Nouba is the meeting of two different worlds—the fantastic world of the circus (马戏团) people who wear bright colors and the boring world of the people living in big cities who wear dark, lifeless clothes.

    Kennedy Space Center

    Duration: Flexible

    Location: Orlando, Florida

    Spend a day exploring the attractive Kennedy Space Center, just 45 minutes from Orlando. Learn about the history of the US space program and watch beautiful IMAX films. Don't miss the chance to walk under a Saturn V rocket, and experience a real moonwalk!

    Sea World Orlando

    Duration: Varies

    Location: Orlando, Florida

    Spend a day at Sea World Orlando and come face to face with the ocean's most attractive sea animals. With several up­close meetings with killer whales, sharks and turtles, you'll feel the energy and excitement of all kinds of sea life.

    South Beach Cultural Food and Walking Tour

    Duration: 2 hours and 30 minutes

    Location: Miami, Florida

    On the South Beach Cultural Food and Walking Tour, you'll explore the Art Deco district of South Beach on foot and along the way, you'll taste a variety of foods that make South Beach such an internationally well­known food region.

    Price information：

    Click the link below to check price information on your preferred travel date. Our price is constantly updated.

    At least 20 people died and hundreds were injured in a bridge collapse in the eastern Indian city of Kolkata Thursday. Witnesses said many people and vehicles, including two buses carrying more than 100 passengers, were under the bridge when it fell. They also said construction workers had set up camps near the bridge site where they would sleep and cook.

    Before rescue teams arrived, local residents and firefighters used their bare hands to try to rescue people trapped under the debris. The collapsed bridge is in a busy commercial area of Kolkata. Its location has made it difficult for rescue operations. Access to the area is blocked on both sides by buildings, and the streets are blocked with heavy traffic.

    Reuters (路透社) reports that the Chief Minister of West Bengal, Mamata Banerjee, rushed to the scene of the collapse. She said that rescuing those trapped is her “top priority”. Banerjee said those responsible for the disaster will be punished. Yet she faces questions about the safety of the construction project. The Telegraph newspaper reported last November that Banerjee wanted the bridge — already five years overdue — to be completed by February. Project engineers said they were concerned over whether this would be possible, the newspaper said at the time. Construction workers had been on a strict schedule to complete the bridge. The disaster could affect the West Bengal election next month. An Indian company, IVRCL, was building the 2­kilometer bridge, its website said. IVRCL's director of operations said the company was not sure of the cause of the disaster.

Before traveling to Lake Tahoe, make sure your plans are in order. Here are several vacation packages to the area offered online. Easily find the perfect route or simply build your own to experience the wonders of Lake Tahoe.

Get Outdoors in Lake Tahoe Package

Get outdoors and explore! With this fun vacation package, you can stay in the Lake Tahoe area for three nights and have a few adventures along the way. This package also features Lake Tahoe Sport Fishing, allowing guests to get out and fish!

Package includes: 3 nights' lodging（住宿）in your choice of over 33 hotels.

Lake Tahoe Romantic Getaway Package

Lake Tahoe Romantic Getaway Package is perfect for people who want to have a romantic time. It also includes the Lake Tahoe Emerald Bay Sunset Cruise on the Bleu Wave, which allows you the chance to see the beautiful surroundings of Lake Tahoe.

Package includes: 4 nights' lodging in your choice of over 11 hotels.

Lake Tahoe Family Vacation Package

Due to the amazing sights, there are lots of activities in this package to take part in. If your next trip happens to be in the Lake Tahoe area, then consider booking the Lake Tahoe Family Vacation Package. Everyone is suitable to visit.

Package includes: 3 nights' lodging in your choice of over 11 hotels.

Lake Tahoe Weekend Getaway Package

Lake Tahoe Weekend Getaway Package is great for people of all ages, so this is a great choice for families. It also includes a Lake Tahoe Emerald Bay Cruise, which takes place aboard the Bleu Wave.

Package includes: 2 nights' lodging in your choice of over 22 hotels.