When someone is happy, can you smell it?

    You can usually tell when someone is happy based on seeing them smile, hearing them laugh or perhaps from receiving a big hug. But can you also smell their happiness? Surprising new research suggests that happiness does indeed have a scent, and that the experience of happiness can be transmitted through smell, reports Phys.org.

    For the study, 12 young men were shown videos meant to bring about a variety of emotions while researchers gathered sweat samples from them. All of the men were healthy and none of them were drug users or smokers, and all were asked to abstain from drinking or eating smelly foods during the study period. 

    Those sweat samples were then given to 36 equally healthy young women to smell, while researchers monitored their reactions. Only women were selected to smell the samples, apparently because previous research has shown that women have a better sense of smell than men and are also more sensitive to emotional signaling—though it's unclear why only men were chosen to produce the scents.

    Researchers found that the behavior of the women after smelling the scents—particularly their facial expressions—indicated a relationship between the emotional states of the men who produced the sweat and the women who sniffed them. 

    “Human sweat produced when a person is happy brings about a state similar to happiness in somebody who breathes this smell,” said study co-author Gun Semin, a professor at Koc University in Turkey.

    This is a fascinating finding because it not only means that happiness does have a scent, but that the scent is capable of transmitting the emotion to others. The study also found that other emotions, such as fear, seem to carry a scent too. This ensures previous research suggesting that some negative emotions have a smell, but it is the first time this has proved to be true of positive feelings.

    Researchers have yet to isolate(分离) exactly what the chemical compound for the happiness smell is, but you might imagine what the potential applications for such a finding could be. Happiness perfumes, for instance, could be invented. Scent therapies（香味疗法）could also be developed to help people through depression or anxiety.

    Perhaps the most surprising result of the study, however, is our broadened understanding of how emotions get communicated, and also how our own emotions are potentially managed through our social context and the emotional states of those around us. 

    There is a story about a man who lost his legs and left arm in an accident. After the accident, only a finger and thumb on his right hand remained.

    He was a brilliant, creative, and educated man. He had gained a lot of experience while traveling around the world, so he became very depressed after his accident. He was afraid that he would spend the rest of his life suffering and would no longer be able to spend his life in a meaningful way. Then, he realized that he still had partial function of his right hand and could still write even though it was very difficult. An idea occurred to him. “Why not write to other people who need encouragement? ”

    He wrote to the prison ministry about sending letters to the prisoners. The prison minister replied, “Writing to the prisoners is acceptable, but your letters will not be answered. ”

    Filled with excitement, the man knew he could write his letters. He began sending one-way messages of God's love, hope, strength, and encouragement. He wrote twice a week, testing his strength and ability to the limit. He poured his heart and soul into his words and shared his experience, sense of humor, optimism, and faith.

    It was difficult to write those letters, especially without hope of a reply. One day he received a letter from the prison ministry. It was a short note from the officer who monitored and checked the prison mail.

    The letter said, “Please write on the best paper you can afford. Your letters are passed from cell to cell until they literally fall to pieces! ”

    No matter what circumstances life may present, we all have unique experiences, abilities, and God-given talents. We can discover ways to reach others who desperately need messages of encouragement and strength.

    For many people who live in cities, parks are an important landscape. They provide a place for people to relax and play sports, as well as a shelter from the often severe environment of a city. What people often overlook is that parks also provide considerable environmental benefits.

    One benefit of parks is that plants absorb carbon dioxide and give off oxygen. According to one study, an acre of trees can absorb the same amount of carbon dioxide that a typical car emits in 11,000 miles of driving. Parks also make cities cooler. Scientists have long noted what is called the Urban Heat Island Effect: building materials such as metal and concrete (混凝土) absorb much more of the sun's heat and release it much more quickly than trees and grass. Because city landscapes contain so much of these building materials, cities are usually warmer than surrounding rural areas. Parks and other green spaces help to lessen the Urban Heat Island Effect.

    Unfortunately, many cities cannot easily create more parks. However, cities could benefit from many of the positive effects of parks by encouraging citizens to create another type of green space: rooftop gardens. While most people would not think of starting a garden on their roof, human beings have been planting gardens on rooftops for thousands of years. Some rooftop gardens are simple container gardens that anyone can create with the investment (投资) of a few hundred dollars and a few hours of work.

    Rooftop gardens provide many of the same benefits as other urban parks and garden spaces, but without taking up the much-needed land. In the summer, rooftop gardens prevent buildings from absorbing heat from the sun, which can significantly reduce cooling bills. In the winter, gardens help control the heat that materials like brick and concrete release so quickly, leading to savings on heating bills. Rooftop vegetables and herb gardens can also provide fresh food for city settlers, making their diets healthier. Rooftop gardens are not only something everyone can enjoy but also a smart environmental investment.

    The Healthy Habits Survey shows that only about one third of American seniors have correct habits. Here are some findings and expert advice.

    ⒈How many times did you brush your teeth yesterday?

    Finding: A full 33% of seniors brush their teeth only once a day.

    Step: Remove the 300 types of bacteria in your mouth each morning with a battery-operated toothbrush. Brush gently for 2 minutes, at least twice a day.

    ⒉How many times did you wash your hands or bathe yesterday?

Finding: Seniors, on average, bathe fewer than 3 days a week. And nearly 30% wash their hands only 4 times a day—half of the number which doctors recommend.

    Step: We touch our faces around 3,000 times a day-often inviting germs（病菌）to enter our mouth, nose, and eyes. Use toilet paper to avoid touching the door handle. And, most important, wash your hands often with hot running water and soap for 20 seconds.

    ⒊How often do you think about fighting germs?

    Finding: Seniors are not fighting germs as well as they should.

    Step: Do you know it is not your toilet but your kitchen sponge（海绵）that can carry more germs than anything else? To kill these germs, keep your sponge in the microwave for 10 seconds.

    Chris Mazdzer won a silver medal in a men's luge (无舵雪橇) singles event at 2018 Pyeongchang Winter Olympics, South Korea — equaling the best finish ever for any member of the US Olympic luge team. In the luge, competitors lie flat, feet first, on a small sled (雪橇). They can travel around an icy track at speeds up to 140 kilometers an hour. The riders control the sled's speed by changing the position of their feet or by moving their shoulders.

    So why did the US luge team win a medal at the Pyeongchang Olympics? Most credit must go to Chris Mazdzer himself. The American said his win was a product of 16 years of preparation and intense training. But another reason for Mazdzer's success could have been the 3-D printing technology, which his team used to make its equipment.

    The term 3-D is short for three dimensional, meaning an object with length, width and height. In 3-D printing, 3-D models are first created as files, or documents, on a computer. The printer then uses a substance (物质) like plastic or metal to create physical objects. The process involves making one layer of material at a time until the objects reach full form.

    The US luge team worked with an American company called Stratasys on the designing and manufacturing process for the sleds. First, the company made a scan, or image, of the body of every member of the luge team. Then, 3-D printing technology was used to create tools for making molds (模子) in the shape of Olympians on top of a sled. The process of designing and tooling sled parts is highly complex and can take several weeks. Officials from the US luge team say 3-D printing can greatly simplify the process, speeding up the production of parts.

    Jon Owen, says the use of 3-D printing has made the team more competitive. It helps the team “continuously adjust designs and run the sleds on the track much faster than traditional processes,” he said. He added that the technology also provides a way to perfectly fit each rider to the sled, while cutting production time and costs.

    Compared with solar and wind energy, which are booming, tidal (潮汐的) power is a loser in the clean - energy competition. But if you did want to build a tidal power station, there are few better sites than the mouth of the River Severn, in Britain. Its tidal range, the difference in depth between high and low tides, of around 15 metres is among the largest in the world.

    Engineers and governments have been toying with the idea since at least 1925. But none of the suggested projects has materialised. Price is one objection. A study thought that tidal energy might cost between ￡216 and ￡368 ($306 - 521) per MWh of electricity by 2025, compared with ￡58 - 75 for seagoing wind turbines (轮机) and ￡55 - 76 for solar panels. Environmentalists also worry that any plant would change the tides, making life harder for wildlife.

    An engineer called Rod Rainey thinks he has a way around both problems. He plans to replace the conventional turbines of previous plans with a much older technology. Specifically, he plans to span (横跨) the river mouth with a line of water wheels. This is a design that dates back to the early days of the Industrial Revolution. Examples can be found fixed to the sides of old watermills (水磨).

    But there would be nothing old - fashioned about Mr Rainey's wheels. Thirty metres high and sixty wide, they would be made from ordinary steel. Two hundred and fifty of them, along with the supporting structures, would be floated into place and secured to the seabed, creating a line 15km long. Together, they could supply power at an avenge ate of 4GW. That is about as much as two biggish nuclear power stations would manage. Substituting one of the wheels with a set of locks would provide a shipping channel about twice the width of Panama Canal, permitting upstream ports such as Avonmouth and Cardiff to continue operating.