“He looks red.” “I’m feeling blue.” “She was green.” How often have you heard these expressions? They are actually fairly common. And they show how color relates to our emotions.

  Actually, color does have physical effect on the human body. It can influence the pituitary gland (脑下垂体), which helps control hormone production. Hormones can affect our moods, so it makes sense that color would, too. But it can also be used to change our moods.

  How do colors relate to moods and emotions?

  Red is all about energy, but it can also indicate anger.

  Orange is simulating, good for times when we just can’t seem to get started with something. It may be useful for reducing stress.

  Yellow is good for mental activities like reasoning and analysis. It can promote self—confidence and is helpful in situations when you need to be more optimistic.

  Green tends to make most people think of nature, since so much of the natural world is green. It’s about connections—with nature, or with our fellow humans. It’s also good for general stress, since it can help balance emotions.

  Blue is relaxing. It can stimulate creativity. Light blue can mean quiet, and dark blue can be depressing.

  White is definitely about peace. But it’s also associate with purity.

  How can you use colors to change your mood? Well, clothing is the most obvious choice. What you wear not only helps you feel a certain way, but also can give a strong impression about you to others—especially people you have never met.

  But you don’t have to change everything about your appearance. Sometimes a cap, a tie or a scarf, in a particular color will have the desired effect—without being too noticeable to others.

The latest version of Google's self-driving car -- a pod-like two-seater that needs no gas pedal (踏板) or steering wheel -- will make its first appearance on public roads this summer. It can drive, brake and recognize road damage without human involvement.

However, the new vehicle is not designed for long trips. It lacks air bags and other safety devices required by the federal government. It cannot go more than 25 miles per hour. The vehicle is electric and has to be recharged after 80 miles. And it can only drive in areas that have been thoroughly mapped by Google.

The final goal, says Google co-founder Sergey Brin, is computer-controlled cars that can get rid of human error, which is a factor in an estimated 90 percent of the 1.2 million road deaths that occur worldwide each year. Self-driving cars also could improve traffic congestion (拥堵) and transport the elderly and disabled.

Convincing drivers that driverless technology is safe is one of the difficulties the company must overcome. Earlier this week, in response to questions from the Associated Press, Google acknowledged 11 minor accidents in the six years it has been testing autonomous cars. Urmson, who directs Google's self-driving car project, says the company is proud of that record. He says all but one of the accidents were caused by drivers in other cars.

"Consumers question whether they can trust self-driving cars to work all the time," says the consulting firm J.D. Power and Associates. In a 2013 survey of U.S. drivers, J.D. Power found only one in five was interested in a fully autonomous car.

Google isn't alone in developing self-driving cars. Mercedes-Benz, Infiniti and other brands already have advanced driver assistance systems. Unlike Google, automakers think self-driving cars will arrive feature-by-feature instead of all at once, giving people plenty of time to adapt to autonomous driving.

But Urmson says that approach is "fundamentally wrong." "We believe that's like saying, 'If I work

really hard at jumping, one day I'll just be able to fly,'" he said.

 Scientists say they have developed a way of testing how well, or badly, your body is ageing. They say it could be applied in many ways.

   A team at King's College London says looking at biological age is more useful than using a date of birth. However, the work, published in Genome Biology, provides no clues as to how to slow the ageing process.

   The team says while some lifestyle decisions, like spending all day on the sofa, could be bad for your health, they do not appear to affect the speed of your body ageing. The team believes combining lifestyle factors and your biological age would give a more accurate picture of your health.

   The researcher tried the test out on samples from a group of 70-year-old men in Sweden. They worked out who was ageing well and who was ageing very rapidly and were able to predict who would die in the next few years.

   There are plans to apply the test to organ transplants in the UK to see if people who are technically old, but have a young biological age, can still donate organs safely. The researchers say it could also alter cancer detection, with people who are ageing rapidly needing to be screened at a younger age.

   Professor Jamie Timmons, from Kings' College London, said the test would also from a useful tool in predicting the beginning of dementia. He also said, "It raises a number of questions, and fierce debate, but it helps predict when a person will die."

   Dr Neha Issar Brown, from the UK's Medical Research Council, said, "This new test holds great potential, as with further research, it may help improve the development of treatment that prolong good health in older age."

   Dr Eric Karan, from the charity Alzheimer's Research UK, said, "There is much interest in developing a blood test for diseases like Alzheimer's but such a test would need to be strictly tested to show it is accurate and sensitive before it could be used in the clinic."

Passenger pigeons(旅鸽)once flew over much of the United States in unbelievable numbers.Written accounts from the 18th and 19th centuries described flocks(群)so large that they darkened the sky for hours.

It was calculated that when its population reached its highest point,there were more than 3 billion passenger pigeons—a number equal to 24 to 40 percent of the total bird population in the United States,making it perhaps the most abundant bird in the world.Even as late as 1870 when their numbers had already become smaller,a flock believed to be 1 mile wide and 320 miles(about 515 kilometers)long was seen near Cincinnati.

Sadly the abundance of passenger pigeons may have been theirundoing. Where the birds were most abundant,people believed there was an ever-lasting supply and killed them by the thousands.Commercial hunters attracted them to small clearings with grain,waited until pigeons had settled to feed,then threw large nets over them,taking hundreds at a time.The birds were shipped to large cities and sold in restaurants.

By the closing decades of the 19th century,the hardwood forests where passenger pigeons nested had been damaged by Americans’need for wood,which scattered(驱散)the flocks and forced the birds to go farther north,where cold temperatures and spring storms contributed to their decline.Soon the great flocks were gone,never to be seen again.

In 1897,the state of Michigan passed a law prohibiting the killing of passenger pigeons,but by then,no sizable flocks had been seen in the state for 10 years.The last confirmed wild pigeon in the United States was shot by a boy in Pike County,Ohio,in 1900.For a time,a few birds survived under human care.The last of them,known affectionately as Martha,died at the Cincinnati Zoological Garden on September 1,1914.

Taking photographs at a birthday or a wedding has become as natural as blowing out candles or cutting the cake. But being crazy about recording every detail of our happiest moments could be damaging our ability to remember them, according to a new research. A study has shown that taking pictures rather than concentrating fully on the events in front of us prevents memories taking hold.

   Dr. Linda Henkel, from Fairfield University, Connecticut, described it as the "photo-taking impairment effect". She said, "People often pull out their cameras almost mindlessly to capture a moment, to the point where they are missing what is happening right in front of them. When people rely on technology to remember for them—counting on the camera to record the event and thus not needing to attend to it fully themselves—it can have a negative impact on how well they remember their experiences."

   Dr. Henkel and her team carried out an experiment in a museum to learn if taking pictures of the exhibits was affecting the ability of visitors to remember what they had seen.

   A group of university students were led on a tour at the Bellarmine Museum of Art at Fairfield University and were asked to either photograph or try and remember objects on display. The next day their memory was tested. The results showed that people were less accurate in recognizing the objects they had photographed than those they had only looked at. It was found that their memory for the details of the objects they had photographed was poorer.

   Henkel's lab is currently investigating whether the content of a photo, such as whether you are in it, affects memory. She is also researching whether actively choosing what to photograph might influence what we remember.

   Previous research suggests that reviewing photos we have taken does help us remember objects, but only if we take the time.

   "Research has suggested that the large volume and lack of organization of digital photos for personal memories discourages many people from accessing and recalling them. In order to remember, we have to access and interact with the photos, rather than just collect them," said Dr. Henkel.