Professional athletes in most sports start to slow down after the age of 35. Some retire (退役). Jamaican Olympic runner Usain Bolt has talked about retiring, for example. He is only 30 years old. But on Thursday, Serena Williams earned a spot in the Australian Open finals. She will face her older sister, Venus, who won her semifinal (半决赛) match a day earlier. It is the first time that the Williams sisters will play in a Grand Slam final since 2009. Venus is 36. Serena is 35. One of them will win the championship (冠军) at last.

    One older champion will play in the men's final, too. Roger Federer qualified for the final by defeating Stan Wawrinka. Federer, like Serena Williams, is 35 years old It will be one of the sport's oldest finals in a long time.

    Ken Rosewall of Australia is the oldest winner of a Grand Slam. He was 37 when he won the Australian Open in 1972.

    Serena Williams is already the oldest winner of a women's Grand Slam match. She won Wimbledon last year at the age of 34.

    Many people are impressed that three of the finalists are 35 or older. All of the players have recently had injuries (受伤). Federer missed six months due to back and knee injuries.

    He told the crowd that he did not think he would be able to make it back to a Grand Slam final.

    The Williams sisters have had difficulties, too. Earlier this month, Venus won a match in New Zealand but withdrew (退出) from the final after hurting her arm. She also learned in 2011 she had the immune system disorder. The disorder kept her from practicing and staying in good physical condition for a number of years.

    Serena took time off to recover from knee and shoulder injuries after losing in the semifinals of the U. S. Open last September. It is the ninth time that the sisters will face each other in a major final. Serena has defeated her sister six of those times. If she wins, Serena will beat Steffi Graff's record for the most Grand Slam titles ever in women's tennis.

    India has many festivals, with some celebrations that last for weeks. However, none of them come even close to Holi, India's most colorful and fun festival. Celebrated on the day following the full moon, this year's festival happens to be on March 19th.

    As with most Indian festivals, this one also has many different folk stories. Most of them center around the success of good over evil. The most popular one is about a king, who hates his son Prahlada for loving the creator of the Universe－Lord Vishnu. When every attempt to stop him fails, his sister, Holika believed to be immune (免疫的) to fire, joins in the effort by inviting the young boy to sit with her inside a huge fire. Helped by the power of Lord Vishnu, Prahlada escapes safely, while the evil Holika is burned to death. To remember this event, huge outdoor fires are lit in the night before Holi in order to clean the air of evil spirits and to celebrate the death of the evil.

    So what's so great about this day? While there are some fun parades (游行) and folk songs and dance performances, the most fun of all is walking to the streets and splashing (泼洒) people with water guns and dry colors and even covering them with entire buckets of colored water. On this day, everybody is fair game, no matter how old or how young.

    At about midday, the splashing comes to an end and people living close to oceans or rivers usually take a bath in the water to clean themselves before going home to a delicious home­made big dinner and a well­deserved short sleep, following this full day of fun and activities.

For some people, music is no fun at all. About four percent of the population is what scientists call "amusic". People who are amusic are born without the ability to recognize or reproduce musical notes (音调). Amusic people often cannot tell the difference between two-songs. Amusics can only hear the difference between two notes if they are far apart on the musical scale.

As a result, songs sound like noise to an amusic. Many amusics compare the sound of music to pieces of metal hitting each other. Life can be hard for amusics. Their ability to enjoy music sets them apart from others. It can be difficult for other people to identify with their condition. In fact, most people cannot begin to grasp what it feels like to be amusic. Just going to a restaurant or a shopping mall can be uncomfortable or even painful. That is why many amusics intentionally（故意地）stay away from places where there is music. However, this can result in withdrawal and social isolation. "I used to hate parties," says Margaret, a seventy-year-old woman who only recently discovered that she was amusic. By studying people like Margaret, scientists arc finally learning bow to identify this unusual condition.

    Scientists say that the brains of amusics are different from the brains of people who can appreciate music. The difference is complex, and it doesn't involve defective hearing. Amusics can understand other nonmusical sounds well. They also have no problems understanding ordinary speech. Scientists compare amusics to people who just can't sec certain colors.

Many amusics are happy when their condition is finally diagnosed. For years. Margaret felt embarrassed about her problem with music. Now she knows that she is not alone. There is a name for her condition. That makes it easier for her to explain. "When people invite me to a concert, I just say, 'No thanks. I'm amusic,'" says Margaret. "I just wish I had learned to say that when I was seventeen and not seventy."

    Let's face it. No one drinks diet sodas for the taste. People drink diet sodas in the hope that it will help them lose weight or at least keep them from gaining it. Yet it seems to have exactly the opposite effect, according to a new study.

    Researchers from the University of Texas said those who drank two or more diet sodas a day had waist size increases that were six times greater than those who didn't drink diet sodas. "What we saw was that the more diet sodas a person drank, the more weight they were likely to gain," said Sharon Fowler.

    The study was based on data from 474 participants in a large, ongoing research project, where the participants were followed for nearly 10 years.

    While the findings are surprising, they also offer some explanations.

    Nutrition expert, Melanie Rogers, who works with overweight patients in New York, has found that when patients are switched from regular to diet sodas, they don't lose weight at all. "We weren't seeing weight loss necessarily, and that was confusing to us," said Rogers.

    So why would diet soda cause weight gain? No one knows for sure yet, but it could be that people think they can eat more if they drink diet sodas, and so over-compensate(补偿) for the missing calories.

    A related study found some sweeteners (甜味剂) raised blood sugar levels in some mice. "Data from this and other potential studies suggest that the promotion of diet sodas and artificial sweeteners may be risky," said Helen P. Hazuda, professor at the University of Texas's school of medicine. "They may be free of calories, but not of consequences."

    What will people die of 100 years from now? If you think that is a simple question, you have not been paying attention to the revolution that is taking place in bio-technology(生物技术). With the help of new medicine, the human body will last a very long time. Death will come mainly from accidents, murder and war. Today's leading killers, such as heart disease, cancer, and aging itself, will become distant memories.

    In discussion of technological(技术的) changes, the Internet gets most of the attention these days. But the change in medicine can be the real technological event of our times. How long can humans live? Human brains were known to decide the final death. Cells are the basic units of all living things, and until recently, scientists were sure that the life of cells could not go much beyond 120 years because the basic materials of cells, such as those of brain cells, would not last forever. But the upper limits will be broken by new medicine. Sometime between 2050 and 2100, medicine will have advanced to the point at which every 10 years or so, people will be able to take medicine to repair their organs（器官）. The medicine, made up of the basic building materials of life, will build new brain cells, heart cells, and so on—in much the same way our bodies make new skin cells to take the place of old ones.

    It is exciting to imagine that the advance in technology may be changing the most basic condition of human existence, but many technical problems still must be cleared up on the way to this wonderful future.

    They still bite, but new research shows lab-grown mosquitoes are fighting dengue fever — a dangerous disease that they normally would spread. Dengue infections appear to be dropping fast in communities in Indonesia, Vietnam, Brazil and Australia that are filled with the specially grown mosquitoes.

    Researchers first injected (注射)mosquito eggs with Wolbachia bacteria that's common in insects and harmless to people in a lab. Infected females then pass the bacteria on through their eggs. Releasing enough Wolbachia carriers, both the females that bite and the males that don't, allows mating(交配)to spread the bacteria through a local mosquito population.

    Rather than using chemicals to wipe out pests, "this is really about transforming the mosquito," said Cameron Simmons of the nonprofit World Mosquito Program, which is conducting the research.

    The first success came from Australia. Mosquitoes carrying Wolbachia were released in parts of North Queensland starting in 2011, and gradually spread through the local mosquito population. Dengue is spread when a mosquito bites someone who is infected, and then bites another person, but somehow Wolbachia blocks that — and local spread has nearly disappeared in those North Queensland Communities, Simmons said.

    The studies are continuing in other countries. But the findings, presented at a meeting of the American Society for Tropical Medicine and Hygiene, suggest it's possible to turn at least some mosquitoes from a public health threat into annoying biters.

    The work marks "exciting progress," said Michigan State University professor Zhiyong Xi, who wasn't involved with the project but has long studied how Wolbachia can turn mosquitoes against themselves.

    More research is needed, specialists cautioned. "The results are pretty exciting — strong levels of reductions — but there clearly are going to be things to be learned from the areas where the reductions are not as great," said Penn State University professor Elizabeth McGraw.