Many studies have shown that the company of pets can help lower blood pressure and raise chances of recovering from a heart attack, reduce loneliness and help control body weight.

Any pet owner will tell you how much joy a pet brings. For some, an animal provides more comfort than a husband/wife. A 2002 study by Karen Allen of the State University of New York measured stress levels and blood pressure in people (half of them were pet owners) while they performed 5 minutes of mental arithmetic (算术) or held a hand in ice water. People completed the tasks alone, with a husband/wife, a close friend or with a pet. People with pets did it best. Those tested with their animal friends had smaller change in blood pressure and returned most quickly to baseline heart rates. With pets in the room, people also made fewer math mistakes than when doing in front of other companions. It seems that people feel more relaxed around pets, says Allen, who thinks it may be because pets don’t judge.

   A study reported last fall suggests that having a pet dog may also have an effect on your body weight. Researchers at Northwestern Memorial Hospital spent a year studying two groups of fat people who were put on a diet-and-exercise program: one group with pet dogs, and the other without. On average, dog owners lost about 11 pounds, or 5% of their body weight; While those without dogs lost about 8 pounds. The pet owners, said researchers, got more exercise overall (mostly with their dogs) and found it worth doing.

C

      Delicate step gives mosquitoes strength to walk on water.

   It's not a magical power. Mosquitoes can walk on water because of the angle at which their legs touch its surface.

   A mosquito's leg is strong enough to bear up to 23 times its total body weight, which is one reason why it can walk on water so effortlessly. This is far greater than the leg strength of other water-walking insects like water striders(水黾), whose legs have been more carefully studied.

   Jian-Lin Liu of the China University of Petroleum in Qingdao and his colleagues thought a mosquito's advantage might also come from the protective wax and microscopic scales(鳞片) coating its legs. They removed these layers(层) and measured the change in the leg's load-bearing capacity(承重能力), but found that the layers were responsible for less than 12.5 percent of the overall supporting force.

   The main player turned out to be the angle between the leg and the water surface. The supporting force was strongest when the leg was nearly parallel to the surface. Any angle greater than 62 degrees would make the mosquito fall through the surface.

The researchers believe that mosquitoes can adjust this angle during landing and take-off to ensure they remain on the water's surface. This ability is very important because many species land on fresh or still water to lay their eggs in it.

    The work could inspire insect-like robots and waterproof materials, the team says.

     How to deal with waste has been a problem since humans started producing it. As more and more people choose to live close together in cities, the waste-disposal（处理）problem becomes increasingly difficult.

       During the eighteenth century, it was usual for several neighboring towns to get together to select a faraway spot as a dump site. Residents or trash haulers（垃圾拖运者）would transport household rubbish, rotted wood, and old possessions to the site. Periodically（定期地）some of the trash was burned and the rest was buried. The unpleasant sights and smells caused no problem because nobody lived close by.
           Factories, mills, and other industrial sites also had waste to be disposed of. Those located on rivers often just dumped the unwanted remains into the water. Others built huge burners with chimneys to deal with the problem.

        Several facts make these choices unacceptable to modern society. The first problem is space.  Landfills(填埋场)are most needed in heavily populated areas. Such areas rarely have empty land suitable for this purpose. Property is either too expensive or too close to residential（住宅区的）neighborhoods. Long-distance trash hauling has been a common practice, but once farm areas are refusing to accept rubbish from elsewhere, cheap land within trucking distance of major city areas is almost nonexistent.

      Awareness（意识）of pollution dangers has led to more strict rules of waste disposal. Pollution of rivers, ground water, land and air is a price people can no longer pay to get rid of waste. The amount of waste, however, continues to grow.

       Recycling efforts have become commonplace, and many towns require their people to take part. However, even the most efficient recycling programs can hope to deal with only about 50 percent of a city’s reusable waste.

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Light travels at a speed which is about a million times faster than the speed of sound. In one second, light travels about 300,000km, but sound travels only 344m. You can get some idea of this difference by watching the start of a race. If you stand some distance away from the starter, you can see smoke come from his gun before the sound reaches your ears. This great speed of light produces some strange facts.   Sunlight takes about 8 minutes to reach us. If you look at the light of the moon tonight,   remember that the light rays（光线）left the moon 1.3 seconds before they reached you.

The nearest star is so far away that the light which you can see from it tonight started to travel towards you four years ago at a speed of nearly 2 million km per minute. In some cases(在某种情况下) the light from one of tonight’s stars started on its journey to you before you were born.
   Thus, if we want to be honest, we cannot say “ The stars are shining tonight.” We have to say, “ The stars look pretty. They were shining four years ago but their light has only just reached Earth.”

What makes one person more intelligent than another? What makes one person a genius, like the brilliant Albert Einstein, and another person a fool? Are people born intelligent or stupid, or is intelligence the result of where and how you live? These are very old questions and the answers to them are still not clear.

We know, however, that just being born with a good mind is not enough. In some ways, the mind is like a leg or an arm muscle. It needs exercise. Mental (done with the mind) exercise is particularly important for young children. Many child psychologists (心理学家) think that parents should play with their children more often and give them problems to think about. The children are then more likely to grow up bright and intelligent. If, on the other hand, children are left alone a great deal with nothing to do, they are more likely to become dull and unintelligent.

Parents should also be careful with what they say to young children. According to some psychologists, if parents are always telling a child that he or she is a fool or an idiot, then the child is more likely to keep doing silly and foolish things. So it is probably better for parents to say very positive (helpful) things to their children, such as “That was a very clever thing you did.” or “You are such a smart child.”

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Millions of youngsters acrossEuropecould suffer permanent hearing loss after five years if they listen to MP3 players at too high a volume for more than five hours a week, EU scientists warned Monday.

The scientistsˈ study, requested by the European Commission, attacked the concept of "leisure(休闲) noise," saying children and teenagers should be protected from increasingly high sound levels -- with loud mobile phones also coming in for criticism.

"There has been increasing concern about exposure from the new generation of personal music players which can reproduce sounds at very high volumes without loss of quality," the Commission, the EUˈs executive arm, said in a statement.

"Risk for hearing damage depends on sound level and exposure time," it said. More and more young people were exposed to the significant threat that leisure noise posed to hearing, it said.

Commission experts estimate that between 50 and 100 million people listen to portable music players on a daily basis.

If they listened for only five hours a week at more than 89 decibels, they would already exceed EU limits for noise allowed in the workplace, they said. But if they listened for longer periods, they risked permanent hearing loss after five years.

The scientists calculated the number of people in that risk category at between 5 and 10 percent of listeners, meaning up to 10 million people in the European Union.

Sales of personal music players have risen in EU countries in recent years, particularly of MP3 players.

Commission experts estimate unit sales between 184 and 246 million for all portable audio devices just over the last four years, of which MP3 players range between 124 and 165 million.

Mobile phones used at excessive volume also came under fire from Meglena Kuneva, the EUˈs consumer affairs commissioner.

"I am concerned that so many young people ... who are frequent users of personal music players and mobile phones at high acoustic(声音的) levels, may be unknowingly damaging their hearing permanently." she said in the statement.

If you’re secretly worried about your smartphone addiction, then the new NoPhone might be just the thing you need. It looks and feels exactly like a smartphone, but it does nothing. It’s just a piece of plastic that you can carry around in your hand to fool yourself.

Dutch designer Ingmar Larsen came up with the idea as a joke along with his two friends. To their great surprise, the idea received a lot of attention online and people from all over the world started placing requests for NoPhones of their own. So that’s when the three friends decided to turn to collect enough fund for mass production.

NoPhone is currently a prototype(模型) that will cost only $12 once it hits the market. It is 5.5 inches high, 2.6 inches wide and 0.29 inches thick, bringing it quite close to the latest smartphones on the market. It is described as “battery free”, “no upgrades necessary”, “shatterproof(抗震)”, “waterproofˈ” and “an alternative to constant hand-to-phone contact that allows you to stay connected with the real world”.

“Phone addiction is everywhere.” the designers insist. “It’s ruining your dates. It’s distracting you at concerts. It’s blocking sidewalks. Now, there is a real solution. With a thin, 1ight and completely wireless design, the NoPhone acts as a substitute to any smart mobile device, enabling you to always have a phone to hold without giving up potential engagement with your direct environment.”

If you’re interested in NoPhone, but concerned about not being able to take selfies(自拍) anymore. Don’t feel upset. The makers do have an upgrade at no extra charge - the mirror sticker. That way, they say, you can enjoy “real-time” selfies with your friends when they’re standing right behind you.

Seeing in Stereo(立体感）

 Have you wondered why you have two eyes and why they are set close together on the front of your face? The reasons are simple and important to the way you see the rest of your world．

   Your eyes are like two small cameras. A camera catches an image of an object and records it on film．Similarly，when you look at something，each eye takes in what it sees and sends this image to the back of the eyeball．Because your eyes are set close together，they view the world from about the same height but from slightly different angles. Working as a team, the eyes send the images to your brain, which puts them together into a single, centered image.

   Seeing in stereo means seeing with two eyes working together，which is called stereoscopic sight．This allows you to view the world in three dimensions，or 3-D．Seeing depth helps you to judge the distance between you and the objects you see and to adjust to the changing angle at which you see something as you move closer to or farther away from it．If images are coming from only one eye, however，only two of these dimensions-height and width-can be perceived．A world seen with one eye is thus two-dimensional，as in a photograph．

    Now consider why your two eyes are on the front of your face．Think of other animals with this same arrangement．They are all animals that hunt，like lions and wolves．Their eyes face directly in front of them．This provides a field of sight about 180 degrees wide，which is called binocular sight．On the other hand，animals that are hunted have eyes on the sides of the head，which provides nearly 360-degree field of sight．In order to stay alive，they need to see things coming from the sides and from behind．However，without stereoscopic sight，they have difficulty determining how far a danger is．

    With sight both stereoscopic and binocular，humans share with animal hunters the ability to see from side to side and to accurately determine the distance．If you think it would be great to have another type of sight，perhaps with hundreds of tiny eyes like many insects do，think again! Each tiny insect eye sees only a tiny part．Besides，what if you needed glasses? Be glad for the eyesight that you have．

New research has shown that you might not just be feeling blue; you may also be seeing it differently. Your mood may affect how you see the world around you, according to a new study. A team of researchers has proved that sadness could have an effect on the way we see colors.

The team, led by psychology researcher Christopher Thorstenson of the University of Rochester, found that people who had a sad mood were less accurate in identifying colors on the blue-yellow axis (轴), compared to people who weren’t feeling sad.

“We were already deeply familiar with how often people use color terms to describe common phenomena, like mood, even when these concepts seem unrelated,” Thorstenson said in a statement. “We thought maybe a reason why these metaphors (比喻) appear was that there really was a connection between mood and identifying colors in a different way.”

Thorstenson and his team are not the first to identify a link between a depressed mood and a difference in recognition. In 2010, Emanuel Bubl and his team atAlbert Ludwigs UniversityFreiburg in Germany first proved a link between mood and identifying colors. This was supported by a 2013 paper by Johnson Fam of the UniversityofSingapore.

The team conducted two studies. In the first, 127 participants were chosen randomly to watch one of two video clips, which had been proved in previous studies to feel either sadness or amusement. They didn’t do that in a specific order. The entire group was then tasked with identifying the colors in 48 continued color changes. The group that had been shown the sad clip was measurably worse at identifying colors along the blue-yellow axis.

For the second study, 130 participants were randomly assigned to watch either a sad clip or a neutral (中性的) one. The sadness group showed reduced ability to identify colors along the blue-yellow axis than the neutral group.

Scope:  What led you to start an urban (城市的) garden?

Denzel:When I was 14, I went on a service trip to New Orleans. My group helped build an urban garden in a neighborhood that had all the same problems as mine. I realized we could make a difference at home too. I came back and worked with friends to find land we were allowed to use, clean it up, and build a garden.

Scope: Tell us about your neighborhood in Philadelphia.

Denzel:There is crime and violence, and everybody used to see it as a place where there was nothing to do. Because there wasn’t a lot of fresh food around, a typical meal would be something like chips, soda, or cheese sticks.

Scope:  What is the urban garden like?

Denzel:We have outdoor gardens and greenhouses where we can grow plants year-round. It’s made a big difference in the neighborhood.

Scope: How?

Denzel:It’s given people something positive to do. Both young kids and older people come to the garden, and we help them grow their own food. They can also help with marketing when we sell food to local restaurants. People are eating healthier, too. Food is connected to everything.

Scope:  What do you mean?

Denzel:If you don’t eat fresh food, you feel tired and unhealthy. People who eat fresh food are more confident. People who grow their own food are even more confident.

Scope:  Has that been true for you?

Denzel:As a young teen, I ate nothing but unhealthy food and was overweight. I felt depressed about where I lived. That changed when I started working on the garden. The physical work helped me get in better shape, and I went from eating chips to salad. I realized I could make a change for the better.