For most caffeine(咖啡因)consumers, its main benefit is that it helps you get more done. This is what makes it unusual, says Stephen Braun, author of Buzz: The Science and Lore of Alcohol and Caffeine.

    “Its appeal is that it helps us earn more money,” he adds. “What makes it different from other drugs is that it's used as a productivity tool –– not for pleasure.”

    Many of history's creative minds have also been connected with a large amount of caffeine consumption (消耗).

    According to one biographer, the French novelist and playwright Balzac drank as many as 50 cups of coffee a day. “Were it not for coffee one could not write, which is to say one could not live,” he once insisted.

    For seven years, the film-maker David Lynch ate at the same Los Angeles diner every day, drinking up to seven sweetened cups of coffee “with lots of sugar” in one sitting, which he said would guarantee that “lots of ideas” arrived.

    Ludwig van Beethoven was said to have painstakingly counted out exactly 60 coffee beans per cup when he brewed(煮)coffee.

    Perhaps recent tales of caffeine excess (过量) featured the singer Robbie Williams, who reportedly consumed 36 cups of black coffee and 20 cans of Red Bull a day.

    It is the routine task itself, as much as the stimulating(刺激的)effects of caffeine, that makes the process so important, says Mason Currey, author of Daily Rituals: How Artists Work. “A lot of artists use the process of making coffee as a gateway to the creative process,” he adds. “You need to get into the right mindset to do that sort of work, and the preparation process provides a focus.”

    One problem with attempting to control caffeine, says Braun, is that it affects everyone differently –– it is impossible to work out a “safe” limit that works for everyone. “Eventually, you have to become your own scientist –– there isn't an alternative to careful self-experimentation,” he says.

Festivals in Wales this spring

    There's lots to see, do and experience in Wales this spring. And now it's time to embrace all things new and get ready to be entertained in the spring, come rain or shine.

    Wrexham, 10-12 May

    The annual festival showcases over 200 acts consisting of music, comedy, film and more. Since its opening event in 2011, Focus Wales has done a lot for emerging（新兴的）musicians across the country, and 2018 sees Welsh Music Prize winner The Gentle Good and Y Selar Best Band winners. Candelas, take the stage.

    Aberystwyth, 19-29 May

    Whether you prefer Hill Climbs or Sportives, the AberCycle Festival allows you to take all of it in from the saddle（鞍）of a bike, enjoying the world's most beautiful scenery. However, all work and no play makes us all dull boys and girls, so while you're in town be sure to pop in to one or two of the plenty of pubs in Aber（as the locals call it）for a nice, cold pint of Brains beer. You'll need it after all that cycling!

    Hay on Wye, 25-28 May

    The world's biggest music and philosophy festival returns in 2018 with its unique mix of tunes, talks and trapeze（吊杠）（yes, there are even circus performers!） Based in the magical surroundings of Hay on Wye, this four day festival takes place at the end of May and is perfect for everyone who likes a side of intellectualism（理智主义）with their traditional festival experience.

Lawrenny, 25-28 May

    In late May in the heart of the Pembrokeshire National Park, the Big Retreat Wales takes place. Essentially the festival is about wellness, but it's also so much more than that. Join in this May for four days of “fed good”, leaving your usual routine behind and diving into a delightful mix of workshops, activities, music and sustainable food produce.

    Everyone should be so lucky as to have a friend like Francia Raisa. On Thursday, singer and actress Selena Gomez, 25, used Instagram to explain why she was “laying low” this summer. She posted a photo of herself in a hospital bed with her friend Francia Raisa holding hands. She said she recently received a kidney transplant from her best friend because of complications（并发症）from lupus（狼疮）, an autoimmune disease, which means it is the result of the immune system attacking normal tissue, including the kidneys, brain, heart and lungs.

    People with lupus may first experience tiredness, joint pain or a little bit of rash（皮疹）on their bodies and can go for a long time before their doctors realize it is more serious. Many people see two or four doctors before the real problem is picked up. According to Dr. Kyriakos Kirou, roughly a third to one-half of people with lupus develop kidney disease, and up to one in five of them will eventually need a transplant, sometimes because they weren't treated with effective drugs to prevent the immune system from attacking the kidneys. Though Gomez said that she was “very well now,” she warned about the dangers of not taking medical diagnoses seriously, like she initially did.

    Her Instagram post also called attention to two major health topics: the need for living organ donators and the fact that Gomez represents three groups more likely to be diagnosed with lupus and lupus-related kidney disease. Nine out of 10 people diagnosed with lupus are women, and most develop the disease between the ages of 15 to 44. And lupus is two to three times more common among women of color, including Hispanic women, according to the Lupus Foundation.

    Raisa is Latina, and Gomez's father is of Mexican origin. While it's not essential that the organ donator and receiver be of the sane ethnicity, people who share a similar background sometimes are better matched, according to data from the United Network for Organ Sharing.

    The following are the top things to do in Tampa Bay on the weekend.

    Plants are living things. So can they feel pain? Plants don't feel pain the same way animals and people do, says Anke Steppuhn. She is a scientist at the Free University of Berlin in Germany. "What we define as pain usually has to do with a nervous system," Steppuhn explains. When you put your hand too close to a hot stove, nerve cells send a signal to your brain. Your brain decodes (解码) that signal as pain. This causes you to pull your hand away before any serious damage is done.

    Plants don't have nerves or brains, so they can't feel pain like we do. "But plants do recognize when something is hurting them," Steppuhn says. Because they are rooted to the ground, they can't escape a dangerous situation. So they need other ways of fighting back.

    The biggest threat to a plant's life is getting eaten. Some plants grow sharp little hairs. Other plants produce bad-tasting or even harmful chemicals. These force an attacker to abandon its meal. A plant called bittersweet nightshade does something even smarter, Steppuhn found. When a slug (蛞蝓) chews holes in a nightshade' s leaf, liquid begins dripping (滴) around the wound. It is almost as if the plant were bleeding. The liquid is sugary nectar (花蜜), and it happens to be a favorite food of ants. In their effort to collect the nectar, the ants swarm (蜂拥而至) all over the injured plant. They will attack anything that stands in their way. That includes the slug that damaged the plant in the first place. It's a very clever trick. Whenever a slug attacks a plant, the plant calls an army of ants to kill the slug.

    Nectar isn't the only way plants attract bodyguards. They also release certain chemicals into the air when they are being eaten. People usually can't detect these smells. But wasps (黄蜂) can. When a wasp detects this cry for help, it races to the scene of the crime. If it finds the right kind of insect chewing down on the plant, the wasp will interrupt the attacker's meal. It will do this by laying eggs inside the insect's body!

Fauja Singh, 109, who broke marathon records and was called the "Superman" before hanging up his running shoes six years ago, will be the subject of a Bollywood film, Fauja, tracing his remarkable career.

Mr. Singh, born in India in 1911, was a keen amateur runner in his youth, but gave it up. Getting over a series of personal tragedies including the deaths of his wife and two of his children, he returned to his former passion in his eighties.

He moved to the UK soon after and now lives in Ilford, east London. He arrived for his first training session in Redbridge in a three-piece suit, and his first race was the London marathon in 2000. Three years later in Toronto, he broke the world record for the 90-plus. In the early 2011, when he turned 100, Mr. Singh set eight world records in a day. He ran the 100m in 23.14, then added the 200m, 400m, 800m, 1,500m, the mile, the 3000m and 5,000m world records. Three of the events had never been attempted by anyone over the age of 100 before. Days later, he became the first centenarian (百岁老人) to complete a marathon, again in Toronto, with a time of 8:25:27.

Mr. Singh retired from competitive running in 2013 but continued jogging for pleasure. He owed his extraordinary longevity to a vegetarian diet and avoiding smoking, alcohol and fried food.

Of marathon running he has said: "The first 20 miles are not difficult. As for the last six miles, I keep talking to myself, 'Keep it up, old boy!'"