What do you do when nobody is around to take your picture? You take a selfie(自拍照). But what about selfies in space? Last year, NASA astronaut(宇航员)Buzz Aldrin who famously became the second man to walk on the moon in July 1969, said that he took the first selfie in space during the Gemini Ⅻ mission in 1966.

"For me, it needs to be digital to be a selfie," argues Jennifer Levasseur, who is in charge of the Smithsonian National Air and Space Museum. According to Levasseur, the idea of a selfie is directly linked to Internet culture and the human wish to interact(互动)on social platforms. "The thing that makes a selfie is sharing it," she says.

Still, astronauts have been carrying cameras aboard space vehicles since the 1960s, and they've taken plenty of pictures of themselves along the way. Astronauts had to pull the film magazines(胶卷暗盒)out and leave their cameras behind when they returned to Earth, because early space missions had a weight limit on the return trip.

A big change in space camera technology came after the sad loss of the space shuttle Columbus, which broke apart on its return to Earth in 2003. "Fearing that they would never be able to bring the film back from space and lose all that hard work quickened the pace for digital," Levasseur says.

Today, astronauts can have access to the Internet and social platforms in space and post true space selfies taken by digital cameras. Taking selfies and sharing them on social media is a way that astronauts in space can participate in the same activities people on Earth do every day. The first astronaut selfie that went viral(网红的)on the Internet was one by Japanese astronaut Akihiko Hoshide in 2012.

An afternoon nap(午睡)is one of the joys of life, although too much napping could signal all is not well. In some cultures, people will have a daily nap—this is fine. The warning comes when people start sleeping during the daytime, when they did not sleep before. There is certainly a good reason to believe that daytime sleepiness—as in the Alzheimer's disease study—can be a marker of an underlying condition.

For most people, napping during the day is mainly a sign that you are not getting enough sleep at night, says Dr. Neill Stanley, a sleep expert. "If you feel sleepy during the day, you should think about taking a nap. That is what the body needs —it doesn't need to be kept awake with caffeine. It needs sleep. "The feeling we should notice is "sleepiness", he says. "It's not tiredness, which could be more psychological and linked to stress."

So how do you nap well? The key thing, says Stanley, is how long your nap lasts. Choose either a 20-or 90-minute nap. "When you fall asleep, you'll quickly go through the lighter stages of sleep into your first period of deep sleep. You don't want to wake up because that's when you wake and feel worse than you did before. "Napping for 20 minutes means you will wake up before you go into deep sleep; napping for 90 minutes means you'll complete a sleep cycle.

Once you factor in the time it takes to fall asleep—"Some people are better at napping than others but, "says Stanley, "a healthy adult will fall asleep in between 5 and 12 minutes. "—you can set an alarm, allowing a 30-to 40-minute period for a short nap, and up to two hours for a longer one.

A good time to nap is during the body's natural dip in the afternoon, between 2 p. m. and 4p. m. "You don't really want to be napping much past that because then you are going to be eating into your night-time sleep, "Stanley says. The point, he stresses, is to get good night-time sleep, which would ensure you probably don't need to nap at all.

As one of the biggest topics of the last decade, sustainability has become the beacon (灯塔) of hope to protect the planet. From supermarkets taking action on plastic packaging to the zero waste movement that can be practised from your kitchen, changes made by individuals and organizations across the globe have had an impact on the way we think, shop and live.

So what does that mean for the world of technology? You'd be forgiven for thinking that the words "sustainable" and "technology" don't usually go hand in hand. E-waste is, after all, one of the planet's biggest contributing waste streams. Not only that, but the materials that go into technology products are also part of the problem.

But with a challenge comes an opportunity, and there's already some brilliant progress happening — great news for those of us wanting to be more sustainable with our technology. Firstly renewed products are having its moment. While consumers would previously turn their noses up at the idea of a second-hand device, there's been a huge surge in demand for renewed technology products. The second major step in tackling the problem of e-waste is a change in attitudes from owning a product to subscribing for one. A subscription for a smartphone might sound like a foreign concept, but it's already gaining momentum. At the forefront of this movement is a London-based technology startup, which offers a subscription service for the latest smartphones. As customers aren't paying to own the phone at the end of their contract, the monthly price is significantly lower than average.

Studies show that extending a phone's lifespan from one to four years can decrease its environmental impact by about 40%. So the next time it comes to refreshing your device — whether a smartphone, a laptop, a tablet or something else——consider the more environmentally friendly options that are at your fingertips.

Many people believe that working to the maximum is the secret to success, but research has found that moderation (适度) also gets results on the job.

In a study led by Ellen Langer of Harvard University, researchers asked people to translate sentences into a new made-up language. Subjects who practiced the language moderately beforehand made fewer errors than those who practiced extensively or not at all. High levels of knowledge can make people too attached to traditional ways of viewing problems across fields — the arts, sciences, and politics. High conscientiousness is related to lower job performance, especially in simple jobs where it doesn't pay to be a perfectionist.

How long we stay on the clock and how we spend that time are under careful examination in many workplaces. The young banker who eats lunch at his desk is probably seen as a, while his colleagues who chat over a relaxed conference-room meal get dirty looks from the corner office. "People from cultures that value relationships more than ours does are shocked by the thought of eating alone in front of a computer", says Art Markman, a professor of psychology at the University of Texas, Austin. Social interaction has been shown to lift mood (情绪) and get people thinking in new directions and in ways that could help improve any post-lunch effort.

Markman also promotes off-task time. "Part of being a good thinker is experiencing things that are seemingly unrelated to what you are working on at the moment but give you fresh ideas about your work," he says. "Also, there is a lot of research showing that a positive mood leads to higher levels of productivity and creativity. So, when people do things to increase their life satisfaction, they also make themselves more effective at work. "

With almost all big employers in the United States now using artificial intelligence (Al) and automation in their hiring processes, the public is considering some urgent questions: How can you prevent discrimination in hiring when a machine is keeping the discrimination? What kind of methods might help?

Some 83% of employers, including 99% of Fortune 500 companies, now use some form of automated tools as part of their hiring process, said the Equal Employment Opportunity Commission's (EEOC) chairwoman Charlotte Burrows at a hearing on Tuesday. She said everyone needs to speak up on the debate over these technologies. The risks are simply too high to leave this topic just to the experts.

Last year, the EEOC issued some guidance around the use of cutting-edge hiring tools, noting many of their shortcomings. The agency found that resume(简历)scanners that prioritize keywords and programs that evaluate a candidate's facial expressions and speech patterns in video interviews can create discrimination. Take, for example, a video interview that analyzes an applicant's speech patterns to determine their ability to solve problems. A person with a speech problem might score low and automatically be screened out. The problem will be for the EEOC to root out discrimination― stop it from taking place.

The EEOC is considering the most appropriate ways to handle the problem. It's agreed that inspections are necessary to ensure that the software used by companies avoids intentional or unintentional discrimination. But who would conduct those inspections is a more challenging question. Each option presents risks, Burrows pointed out. A third party may turn a blind eye to its clients, while a government-led inspection could potentially stop innovation.

In previous remarks, Burrows has noted the great potential that AI decision-making tools have to improve the lives of Americans, but only when used properly. "We must work to ensure that these new technologies do not become a high-tech pathway to discrimination," she said.

Most people feel that dreams are unique to humans, but many dog owners will likely disagree. They have noticed that their dogs at various times during the sleep may shake legs, snort (哼) and sometimes growl (低声吼叫) which gives the impression that they are dreaming. These things may wonder us about whether dogs dream.

Scientists confirm that dogs probably do dream. It turns out that dog brains and human brains have many similarities during sleep cycles. Researchers used special machines to measure electrical activity in a dog's brain and a human's brain. Scientists already knew that when humans dream, a certain part of the brain is active during sleep. Researchers discovered that the same part of the brain is active in sleeping dogs. Scientists have other data that back up these findings.

Many people dream that they are trying to move but cannot. Interestingly, part of that experience is not a dream. When people sleep, the brain produces a chemical that causes the dreamer to become temporarily paralyzed (使麻痹). Researchers think this happens so that people cannot physically act out dreams while they are sleeping. Dog brains make the same chemical. In one study during which this chemical was blocked, sleeping test dogs performed physical activities, such as standing up, sniffing around the room for imaginary rabbits, or chasing imaginary balls.

Because of these similarities, researchers believe that the content of a dog's dream might come from the same source as a human's dream. "People's dreams are usually based on things they did that day," says Dr. Samantha Hudspith. "So we have reasons to believe that dogs dream about the things they've done that day. Of course, there will never be a way to prove this. Dogs cannot describe their dreams the way that humans can."

A Dutch company has announced that it will start making the world's first production car fitted with solar panels. The company will have solar panels in its roof, hood(引攀盖) and trunk(后备厢) that recharge the electric battery.

The car will be able to drive around 388 miles without stopping to recharge, and will have an additional range of up to 44 miles a day from the solar panels. For comparison, that's slightly more than the best known electric automobile (374 miles).

Each hour in the sun will add up to six miles of charge to the battery. The solar range will not only give an added drip feed of miles for long journeys but also means you'll spend less time at charging points—or may not even need them at all.

The car has much in common with its previous model that was revealed two years ago, but is able to do more with a smaller battery, says company CEO and co-founder Lex Hoefsloot. "The powertrain(动力总成) is the most efficient in the world, " he claims, adding that the car's shape and four in-wheel motors enable a smaller battery to provide the same range. "That's how we've been able to get to 1, 575 kilograms. If you look at other cars that offer similar range, they're all about 40% heavier. "

The whole concept of the car is based around improving efficiency and cutting charging time. It has a maximum speed of just 100 miles per hour, while its 0 to 100 miles per hour is a slow 10 seconds, something that Hoefsloot admits is down to a focus on range. It's expensive too: One will cost you € 250. 000-slightly more than a luxury sports car. The company hopes to launch a "people's model" by 2025, which will be sold for around €30. 000.

At the end of 2018, the Beidou Navigation Satellite System （BDS北斗卫星导航系统） started to provide global services. "This marked Beidou's entering a 'global era' from its 'regional era',  " BDS Spokesman Ran Chengqi said at a news conference.

Now with two more Beidou satellites launched on Dec. 16th, 2019, BDS has 53 satellites in orbit-more than US government's Global Positioning System（GPS）, which has 31 active satellites. That launch means the core of Beidou's third-generation network is now in place. It is expected to greatly improve the system's ability to serve users worldwide.

A signal receiver on Earth-your smart phone, for example, measures its distance from at least three satellites by recording the amount of time it takes to receive their signals. Then it can calculate its location. With so many satellites, BDS can provide a more accurate calculation. While GPS calculates locations to within a few meters, BDS reduces the error to centimeters. This high-precision service is useful for land surveying, mapping, agriculture and automated driving.

China is willing to share BDS with the world. According to Ran, BDS products have been exported to more than 120 countries and regions. "The Beidou system will always stick to the development idea of 'China's Beidou, the world's Beidou and the first-class Beidou', serving the world and benefiting mankind, " Ran told reporters after the latest launch. He added that future plans call for a smarter and more accessible system with Beidou as its core, to come online by 2035.

Windows are hard. They are particularly hard in northern countries like Sweden, where during winter the days are short and the sun is very low in the sky. Window design in cold climate is a technical balancing act. You want it big to get the light, but you want it small to minimize the heat loss. But there is so much more that windows have to do for our social and emotional well-being.

A recent study published in Buildings and Cities looks at the many roles that windows play and the way people use them, exploring daylight, the visual connection to the outside and the role of windows in the home during the day and night. Windows do much more than just provide light and air: "Windows represent an enjoyment of the home and fulfil much more than physical needs. They must allow sufficient personal control over fresh and cool air, sound, sunlight, street lighting and privacy. "

The study authors, Kiran Maini Gerhardsson and Thorbjorn Laike, interviewed occupants living in multi-family dwellings. Windows turned out to be very important for occupant comfort, for visual connection to the outside. But they also had to be able to be screened for privacy; sometimes these conflicted. Sometimes the sill height was important. One occupant, Dmitry was going to add some frosted film to the bottom of his window. "I don't want to see the faces of others when I'm sitting down, but when I'm standing and see their faces, I can wave to them," he said.

Interviewees preferred daylight to artificial light for many reasons, including as a time indicator, and "because it varies, increases room brightness and improves mood". Our bodies need the change from red to blue and back to red.

The authors conclude windows serve many functions that go beyond just light and air and should be designed accordingly. "There is much more to such experiences than the satisfaction of physical needs. Perceiving a room to be enough daylight, adequately pleasant and spacious seems to be equally essential, and a view of the world outside brings information to inhabit-ants. However, windows also need to prevent people outside from peering in moderate bright sunlight during the day. "

When faced with the decision to get out of bed or have a few more minutes of sleep, which do you choose? Believe it or not, that decision could make a world of difference in the rest of your day.

About 85 percent of Americans use an alarm clock to wake up in the mornings, according to sleep researcher Till Roen. And while there are no official numbers on snoozing(打盹), a quick survey of social media makes it clear that hitting the snooze button is a popular pastime(消遣).

As to how the snooze button will affect your day, scientists have mixed opinions. Some scientists think people who hit the snooze button in the mornings are actually clever, creative and happy while some said that hitting the snooze button will ruin your life, or at the very least your day. "I feel that hitting the snooze button has got to be one of the worst things that ever happened to human sleep, " researcher Jonathan Horowitz said. "The chances of you ‘snoozing' and actually experiencing a meaningful rest are close to zero. "

According to some sleep experts, when hitting the snooze button, you are in fact confusing your body and mind, and throwing yourself into a deep state of being sleepy. The body needs some time to wake up. Therefore, when returning to what will be a light sleep for a brief period of time, you are putting your body back into a sleep mode before waking it again. At that point your body won't know what it wants, resulting in a sort of half awaken state.

If you really want to take advantage of an alarm clock, the key is to form a healthy sleep cycle. Focus your efforts on getting enough sleep each night and waking up at the same time each day so that when your alarm goes off you feel rested.