A report says older adults who test their minds with increasingly difficult projects have better mental ability than those who do less demanding activities.

    To keep our brains sharp as we age, we are often told to keep our minds active. As the old saying goes, “Use it or lose it.” But, there is very little scientific evidence to support than.

Denise Park is head of the university's Center for ? Vital Longevity. She designed a study in which she and her tern placed 221 healthy aging and older adults into one of three groups.

    “We asked people to learn new things, like quilting or photography. We asked other people to just do fun things like being in a social group function but were not likely to have a very large effect.”

    The subjects took part in their assigned activities for 15 hours a week over three months. At the end of that time, the researchers found that the adults who learned new skills, such as digital photography, showed the greatest improvements on memory tests.

    No improvements were seen in the results of those in the social group that did activities together like going on field trips. There were also no improvements among the third group that listened to classical music or did crossword puzzles.

    Denise Park believes one reason for improved memory in the active learning group is that its members were being pushed to learn new skills. The other groups took part in what she call receptive activities. Learning new skills may not cure age-related mental decline. But, Ms. Park thinks being mentally active slows down the process.

Denise Park says the latest information shows that the improvements lasted for at least a year. She and her team plan to do longer follow-up studies with all three groups. She also is interested in learning whether taking part in demanding mental activities delays the development of conditions like Alzheimer's disease.

    One morning, Ann's neighbor Tracy found a lost dog wandering around the local elementary school. She asked Ann if she could keep an eye on the dog. Ann said that she could watch it only for the day.

    Tracy took photos of the dog and printed off 400 FOUND fliers（传单）, and put them in mailboxes. Meanwhile, Ann went to the dollar store and bought some pet supplies, warning her two sons not to fall in love with the dog. At the time, Ann's son Thomas was 10 years old, and Jack, who was recovering from a heart operation, was 21 years old.

    Four days later Ann was still looking after the dog, whom they had started to call Riley. When she arrived home from work, the dog threw itself against the screen door and barked madly at her. As soon as she opened the door, Riley dashed into the boys' room where Ann found Jack suffering from a heart attack. Riley ran over to Jack, but as soon as Ann bent over to help him the dog went silent.

     “If it hadn't come to get me, the doctor said Jack would have died,” Ann reported to a local newspaper. At this point, no one had called to claim the dog, so Ann decided to keep it.

    The next morning Tracy got a call. A man named Peter recognized his lost dog and called the number on the flier. Tracy started crying, and told him, “That dog saved my friend's son.”

    Peter drove to Ann's house to pick up his dog, and saw Thomas and Jack crying in the window. After a few moments Peter said, “Maybe Odie was supposed to find you, maybe you should keep it.”

    Nothing could stop Dad. After he was put on disability for a bad back, he bought a small farm in the country, just enough to grow food for the family. He planted vegetables, fruit trees and even kept bees for honey.

    And every week he cleaned Old Man McColgin's chicken house in exchange for manure(肥料).The smell really burned the inside of your nose. When we complained about the terrible smell, Dad said the stronger the manure, the healthier the crops, and he was right. For example, just one of his cantaloupes filled the entire house with its sweet smell, and the taste was even sweeter.

    As the vegetables started coming in, Dad threw himself into cooking. One day, armed with a basket of vegetables, he announced he was going to make stew(炖菜).Dad pulled out a pressure cooker and filled it up with cabbages, eggplants, potatoes, corns, onions and carrots. For about half an hour, the pressure built and the vegetables cooked. Finally, Dad turned off the stove, the pot began to cool and the pressure relief valve sprayed out a cloud of steam. If we thought Dad's pile of chicken manure was bad, this was 10 times worse. When Dad took off the lid, the smell nearly knocked us out.

    Dad carried the pot out and we opened doors and windows to air out the house. Just how bad was it? The neighbors came out of their houses to see if we had a gas leak!

    Determined, Dad filled our plates with steaming stew and passed them around. It didn't look that bad, and after the first wave had shut down my ability to smell, it didn't offend the nose so much, either. I took a taste. It would never win a prize in a cooking competition, but it was surprisingly edible, and we drank up every last drop of soup!

    The first person in the world to receive two facial transplants says he is feeling well, three months after his latest groundbreaking operation.

    Jerame Hamon had his first transplanted face removed last year after signs of rejection following a treatment with an antibiotic (抗生素) during a cold.

    The 43 year old remained in a hospital in Paris without a face for two months while a compatible donor was sought.

    He said: “The first face I accepted immediately. This time it's the same.”

    Mr. Hamon suffers from neurofibromatosis (多发性神经纤维瘤), a genetic condition that spoiled his face severely.

    His first transplant, in 2010, was a success, but he caught a common cold in 2015 and was given antibiotics. The drug was incompatible with the immunosuppressive (免疫制疫的) treatment he was having to prevent a rejection of the transplanted material.

    The first signs of rejection came in 2016 and last November, the face, suffering from the death of most of cells, had to be removed.

    Mr. Hamon lived without a face in a room at Georges-Pompidou hospital in Paris without being able to see, speak or hear until January, when a face donor was found and the second transplant carried out.

    To avoid further rejection, Mr. Hamon—dubbed “the man with three faces” by French media ―had special treatment to clean the blood prior to the transplant.

    His new face remains smooth and motionless, and his skull, skin and features are yet to be fully matched. But he is positive about his recovery.

    “If I hadn't accepted this new face it would have been terrible. It's a question of identity… But here we are, it's good, it's me,” he told AFP news agency from the hospital, where he is still recovering.

    The hours-long operation was led by Prof Laurent Lantieri, a specialist in hand and face transplants who carried out Mr. Hamon's initial surgery eight years ago.

    “Today, we know that a double transplant is practicable, it's no longer in the field of research,” he told Le Parisien newspaper.

    Anaesthetist Bernard Cholley said: “Anyone who loses their face and then has to wait for a possible and imagined transplant for an unknown length of time—that's something that nobody has ever had to go through here.”

    “I'm amazed by the courage of a patient who has been able to get through such a different experience.”

    The first face transplant was carried out in 2005 in northern France. Since then, some 40 operations have been performed around the world.

    The values of artistic works, according to cultural relativism（相对主义）, are simply reflections of local social and economic conditions. Such a view, however, fails to explain the ability of some works of art to excite the human mind across cultures and through centuries.

    History has witnessed the endless productions of Shakespearean plays in every major language of the world. It is never rare to find that Mozart packs Japanese concert halls, as Japanese painter Hiroshige does Paris galleries. Unique works of this kinds are different from today's popular art, even if they began as works of popular art. They have set themselves apart in their timeless appeal and will probably be enjoyed for centuries into the future.

    In a 1757 essay, the philosopher David Hume argued that because “the general principles of taste are uniform（不变的）in human nature,” the value of some works of art might be essentially permanent. He observed that Homer was still admired after two thousand years. Works of this type, he believed, spoke to deep and unvarying features of human nature and could continue to exist over centuries.

    Now researchers are applying scientific methods to the study of the universality of art. For example, evolutionary psychology is being used by literary scholars to explain the long-lasting themes and plot devices in fiction. The structures of musical pieces are now open to experimental analysis as never before. Research findings seem to indicate that the creation by a great artist is as permanent an achievement as the discovery by a great scientist.

Even though they're not the most exciting things in the world, plants have fascinated us ever since the days of early humans. They may not do any tricks or greet us when we come home at night like a dog would, but that doesn't mean they're any less interesting than animals.

However, just when we thought we knew everything we could about them, a recent study found that plants may possess a secret ability that's gone unnoticed all this time. According to the study by Australian biologist Monica Gagliano, published in the journal Oecologia, plants may be able to hear sounds.

To come to this conclusion, Gagliano and her team planted pea seedlings in a pair of different Y-shaped pots with two arms. The first pot's arms led to fresh water, while the other's led to either dry soil or a sealed plastic tube containing flowing water.

Naturally, the first pot's seedlings grew toward the water. What's surprising, however, is that the second pot's seedlings grew toward the sealed water supply and not the soil.

They just knew the water was there, even if the only thing to detect was the sound of it flowing inside the pipe, Gagliano told Scientific American. Gagliano believes that plants are able to use their leaves to detect sound waves, which make tiny vibrations (振动) as they're produced.

This could explain why so many people believe that singing or playing music to their plants helps them grow.

I had a plant that I used to wash the leaves once a week and sing to it, plant lover Heather Goodall told BBC News. It grew from being about 2 feet tall to 7 feet tall in just a couple of years.

So, does this mean we should start treating our plants like pets? Not necessarily, although perhaps it does mean we should give them more respect. I would like to see plants acknowledged more as the amazing, interesting, exotic living beings they are, and less as a mere source of human nutrition, Fatima Cvrckova, a scientist at Charles University in the Czech Republic, told BBC News.