Next time you hear a funny joke you’d better not laugh too hard. According to a paper published by the British Medical Journal, laughter isn’t always the best medicine. Sometimes it can even be harmful. Professor Robin Ferner from the University of Birmingham, one of the authors of the study, found that bad things could happen to people who laughed too much. He says: “We found people with heartbeat problems which had stopped their heart, we found people who had fainted (昏倒), and we found people who’d dislocated their jaws or burst their lungs.”

It seems that laughing can be no laughing matter. But it’s not all doom and gloom. Professor Ferner says there are benefits to laughing when you want to lose weight, for example. Yes, that’s right: laugh and be slimmer! Professor Ferner explains that: “You use energy when you laugh, you move your diaphragm (横膈膜), you expand your lungs, and both those things can be helpful.”

According to the research, laughing for a quarter of an hour can burn up to 40 calories, and if you laughed all day you’d use up about 2,000 calories, which is what most people consume in a day. But don’t do that or you might end up with a painful jaw. Ouch! Or you might find people looking at you in a funny way.

But I don’t want to finish this article leaving you feeling desperate. Laughter comes naturally for most of us. Babies begin to laugh at around 3-6 months. So give in to your sense of humor and keep smiling. Life is short anyway.

Called ocean thermal energy conversion (OTEC), the idea is to use surface water warmed by the sun to heat a fluid such as ammonia or water, which then runs a heat engine to produce energy, just like a power plant driven by steam. Cold water from deeper layers of the ocean would then be piped up to cool the fluid and repeat the cycle. Theoretically, oceans could provide vast amounts of electricity like this. Researchers have estimated that there is enough ocean heat to supply 7,000 gigawatt s a year without affecting ocean circulation, enough to supply the world’s electricity demand— if we can access it.

The idea was first put forward in 1881, but went largely unexplored until the 1970s oil. crisis drove a search for new sources of energy. In the years since, demonstration projects have been built, but progress has been “disappointing”, says AI Binger at SIDS DOCK, an organisation that promotes clean energy development in small island countries. In recent years, a fresh urgency to transition away from fossil fuels has brought a suggestion of an OTEC return. “It’s the most promising it’s been in many decades,” says Andrea Copping at the Pacific Northwest National Laboratory in Washington state.

Tropical (热带的) islands are good candidates for OTEC because of their high energy costs— diesel (柴油) generators are common there—and the presence of deep cold water not far from shore, says James Van Zwieten at Florida Atlantic University. Islands also have less space for other types of renewables. A barrier for past projects was the cost of fixing kilometres of large pipes to reach deep water. Global OTEC aims to avoid that by extending a shorter pipe from a platform floating in deep water 10 kilometres offshore, then transmitting electricity back via a cable (电缆), and making use of advances made in offshore wind technology.

“OTEC will be part of providing a reasonable energy transition so these places aren’t depending on diesel imports from the richest petrol states in the world,” says Dan Grech, Global OTEC’s CEO.

In a digital age, we almost never write things by hand. However, multiple studies have shown that this act has many benefits.

New brain research, led by researchers at the Norwegian University of Science and Technology, confirms the same choosing handwriting over using a keyboard results in better learning and memory.

“When you write your shopping list or lecture notes by hand, you simply remember the content better afterwards,” said Audrey Van der Meer, author of the study.

The study was conducted using equipment to track and record brain wave activity. The participants included 12 young adults and 12 children. This is the first time that children have participated in such a study. Each subject was asked to write by hand and type on a keyboard while wearing a hood(风帽) with over 250 electrodes(电极). The sensors(传感器)in the electrodes are very sensitive and pick up the electrical activity that takes place in the brain. Each examination took 45 minutes per person.

The results showed that the brain in both young adults and children is much more active when writing by hand than when typing on a keyboard. According to Van der Meer, plenty of senses are activated (激活) by pressing a pen on paper, seeing the letters written and hearing the sound made while writing. These sense experiences build contact between different parts of the brain, opening the brain up for learning.

Van der Meer believes that the outcomes stress the importance of children being challenged to draw and write at an early age, especially at school. “Learning to write by hand is a bit slower process, but it’s important for children to go through the tiring phase of learning to write by hand”, she said.

The hand movements used to form the shapes of letters are beneficial in several ways. “If you use a keyboard, you use the same movement for each letter. Writing by hand requires control of your fine motor(精细动作)skills and senses. It’s important to put the brain in a learning state as often as possible,” Van der Meer added. For example, you might use a keyboard to write an essay, but you should take notes by hand during a lecture.