What do you think of cats? Some people think very lovely. But not all people love cats. Compared with dogs, cats seem to be very lazy and unfriendly. Besides, cats are not known for acts of selflessness (无私). But maybe we're wrong about them. Don't believe it? Then meet Pippa, a very unusual cat.

    The black-and-white cat was left in a box outside a shop and taken by the British RSPCA to the Jansa family in Whitstable, Kent. They really loved her character (性格) and decided to adopt (收养) it，but they never guessed she'd become a lifesaver.

    Eight-year-old Mia Jansa had diabetes and had become good at testing her blood during the day, as well as having something to eat or drink to bring her blood sugar levels back. But the danger was at night. Mia could easily experience hypoglycemic (低血糖症的) situations when she was asleep, which could cause even death.

    Soon after she was adopted, Pippa went into Mia's bedroom in the middle of the night and woke her up. When the child tested her blood sugar levels, she found they were dangerously low. Ever since, Pippa always visits Mia at night. If she can't get her to wake up, she raises the alarm.

    “Pippa does this of her own accord,” says Mia's mother Laura. “We don't make a request for caring because we don't want to encourage wrong alarms. She gets plenty of hugs. It gives me peace of mind and I know someone else is keeping an eye on Mia.”

    Now the family is so happy that they've chosen to adopt it in the first place.

    Some inventions are so useful, but seem so simple, that we wonder why no one thought of them long ago. Post-it Notes, the pieces of paper that you can stick almost anywhere and then remove without leaving any sign that they are there, are an example of such an invention.

    Post-it Notes were invented about twenty years ago by Art Fry, a scientist at 3M Corporation. The idea for the product came from an upsetting experience he often had while singing in his church choir. Fry used pieces of paper as bookmarks to mark the places in his book of songs, but these bookmarks were always falling out. He knew he needed a bookmark that would stay where he put it, but that he could remove without damaging the pages.

    Around that time, Fry heard about a new adhesive(粘合剂) that a colleague, Dr. Spence Silver had created. This adhesive was special because it was sticky, but not too sticky. It was strong enough to hold papers together, but weak enough not to tear the paper when it was removed. Fry saw that the new adhesive could help solve his bookmark problem. One morning, Fry put some of the adhesive on the edge of a piece of paper. Just as he hoped, it made a perfect bookmark.

    A short time later, Fry realized that his new invention had even more uses than being a great bookmark. He came to this realization when he wrote a note on one of his new “bookmarks” and attached it to a report he was going to give to a colleague. Soon, co-workers were asking Fry for more sample of his invention so that they could use the new type of notes themselves.

    Fry and some other people at 3M believed so much in the new product that they persuaded the company to give away thousands of the sticky pieces of paper for trial use. When some salespeople at 3M went to offices and showed workers just how helpful the new type of notes could be, they immediately received many orders. As more and more people discovered how useful Post-it Notes could be, the product took off.

    Judy Wright and her husband decided to move closer to their son, Chris, who lived in Georgia. About a month after the move, Judy fell ill, suffering from her ongoing battle against Parkinson's disease.

    Her condition worsened rapidly and she required medical care at home. The family hired a nursing aid who canceled at the last minute. Instead, a woman named TunDe Hector showed up in her place.

    One day, TunDe shared a story with Judy and her family. She remembered a particularly difficult day in 2014, when a stranger had helped her with a kind gesture. She had run out of gas, and with only$5 in her pocket, was walking to a gas station, gas can in hand. A man saw her walking and turned his car around. He paid for her gas and gave her all the cash left in his wallet. Upon hearing the story, Judy's son, Chris, took off his hat and said, "That was me!” He was the stranger that had helped TunDe on that difficult day.

    During the care of Judy, the Wright family learned about TunDe's family and her own dream. The nursing aid, TunDe hoped that one day she could become an OB-GYN nurse.Her tuition was past due(逾期) and she had a family to care for, but she was determined to achieve that goal for herself and her family.

    Judy died on July 9,2017. Instead of flowers, her family asked mourners(悼念者) to donate to TunDe's education , to assist her in paying for her nursing school. In less than a week, they raised more than $8,000 and presented her with the surprise check.

    With its snow-covered mountains and a variety of wildlife, Yellow Stone National Park is one of the scenic treasures of the United States. Located primarily in Wyoming, the park hosts millions of visitors every year. If you plan to travel within the park, keep in mind advice from the National Park Service.

    Seasonal Travel

    Travel varies vastly from season to season. Roads are generally open in the summer except for cases of rock or mud slides, wild fires, accidents or road construction. Early snows in the fall can cause some roads to close temporarily. In the winter almost all roads are closed to motor vehicles, but snowmobiles and other snow vehicles with tracks are allowed. Roads begin to open for the spring by the latter part of April but can close if snowfall continues.

    Driving Time

    Grand Loop is the main road through Yellowstone National Park; it passes by most of the major attractions. These include Old Faithful, Yellowstone Lake and the Grand Canyon of Yellowstone. The maximum speed limit on the Grand Loop is 45 miles per hour, but the speed limit drops during some of the winding and twisting sections of this narrow road. Allow yourself at least two days to fully travel the loop due to the size of the park and being sometimes stuck in heavy traffic.

    Safety Awareness

    Buffalo(水牛)often block the roads in the park as they move through the fields. If a group is traveling across the road you are on  you can either wait for them to pass or find an alternative route. If you get out of your vehicle, the National Park Service says to stay at least 25 yards from any buffalo (and 100 yards or more away from bears and wolves). Buffalo are particularly unpredictable and charge people at speeds up to 30 mph.

    You can take your bicycle on any public roads and routes designed for bikes, but bicycles are not allowed on the park roads which are narrow with few shoulders. Altitudes range from 5, 300 to 8, 860 feet. The National Park Service recommends cyclists wear helmets and noticeable clothing.

    Every summer, my family and I visit our relatives in India and whenever we travel, my parents always remind me to drink only bottled or boiled water. On one of my trips to India, I saw children drinking water from the roadside. I was troubled to learn that millions of people, most of them children in developing countries, die each year because of water related diseases.

    Living in the US, I am lucky to be able to turn on the tap and get potable water(饮用水), while one sixth of the world's population lacks access to clean water This year, I entered the Discovery Education 3M Young Scientist Challenge. In late June, I learned that I was selected as one of the top 10 national finalists of this famous middle school science competition. Over the summer, I worked with Dr. Jim Jonza, my Scientist mentor(导师 )from 3M, and developed a system that uses solar energy to purify water. My invention is green and cost effective, and I am looking forward to implementing this in places that are affected(影响)by harmful water pollution.

    In October, my family and I flew to 3M Headquarters in St Paul, Minnesota, where the final event was to be held. For the last challenge, each of us had to present the invention we had been working on over the summer. The first place winner would win $25,000, a trip to Costa Rica, and the title of America' Top Young Scientist. At the awards ceremony, all of us waited anxiously until one of the judges, Danny Forester, started announcing "The winner of the Discovery Education 3M Young Scientist Challenge is…" You could hear a pin(大头针) drop as he opened the paper with the winner' s name, "Deepika Kurup!"

    As America's Top Young Scientist, I was given an opportunity to show my invention on national television and deliver several presentations. One of the most important things I have learned is that communication and teamwork are key to success.

    The new president of Harvard University is the son of an Eastern European refugee and Auschwitz (奥斯威辛) survivor—Lawrence S. Bacow. His father worked full time while attending a state college in Detroit at night to earn his degree.

    Bacow, the former president of Tufts University, has taken over Harvard at a time when higher education is under attack for being financially out of reach to many Americans. But Bacow said his family's journey had reflected the power of college education to transform generations and the opportunities that have historically been available in the United States.

    "My parents came to this country with almost nothing," Bacow said. "I wouldn't be here if this country had not been open to people like my parents at that time. Nor would I if my father hadn't had the opportunity to get the college education."

    Bacow grew up in Pontiac, Michigan. His father's family fled anti-Jewish (反犹太的) violence in Minsk, then part of the Soviet Union, before the start of World War II and went to the United States. His mother arrived in Brooklyn at age 19, having survived Auschwitz concentration camp. She was the only Jew from her town to have survived the war. Yet Bacow, who is married with two sons, said that while growing up in Michigan, he had a happy childhood, entering science fairs as a child and building radios like his dad.

    Bacow has spent most of his professional career at MIT, Harvard and Tufts. He was a professor of environmental studies at MIT, and later a principal at the university. He led Tufts from 2001 to 2011. At Tufts, Bacow earned a reputation for shaking up a sleepy university that was being overshadowed by its peers in Boston. He is also credited with leading it through both 9/11 and the 2008 financial crisis.

    As the Tufts president, Bacow traveled around the country, reaching out to alumni (校友), and he urged his faculty and deans to do the same, in an effort to boost donations to finance Tufts' academic ambitions. He raised more than $20 million for faculty recruitment, attracting up-and-coming professors by offering junior faculty perks (福利), such as long academic leaves that they couldn't get elsewhere.

    Under Bacow's leadership, Tufts spent millions on labs and libraries. He also made addresses nationally about the need to make higher education more accessible and affordable to low-income students.