Next, cover the hole with the plastic sheet, securing the edges of the plastic with dirt and weighting the sheet’s center down with a rock. The plastic should now form a cone(圆锥体) with 45-degree-angled sides. The low point of the sheet must be centered directly over, and no more than three inches above, the cup.

Special Bridges Help Animals Cross the Road

— Reported by Sheila Carrick

Why did the chicken cross the road? To get to the other side.

Most people know this joke. But recently, some people have been much more worried about how the grizzly bear(灰熊) and mountain lion can cross the road.

“Millions of animals die each year on US roads,” the Federal Highway Administration reports. In fact，only about 80 ocelots, an endangered wild cat, exist in the US today. The main reason? Road kill.

“Ecopassages (生态通道)” may help animals cross the road without being hit by cars. They are paths both over and under roads. “These ecopassages can be extremely useful, so that wildlife can avoid road accidents,” said Jodi Hilty of the Wildlife Protection Society.

But do animals actually use the ecopassages? The answer is yes. Paul Beier of Northern Arizona University found foot marks left by mountain lions on an ecopassage that went under a highway. This showed that the lions used the passage.

Builders of ecopassages try to make them look like a natural part of an area by planting trees on and around them. Animals seem to be catching on. Animals as different as salamanders(火蜥蜴) and grizzly bears are using the bridges and underpasses.

The next time you visit a park or drive through an area with a lot of wildlife, look around. You might see an animal overpass!

Did you know that a turtle (乌龟) can lay 12 eggs in one minute? A large sea turtle lays around 150 eggs at a time. She lays all these eggs in just a few minutes.

Large sea turtles live in the warm seas of the world. Except for when they lay their eggs, they spend their whole lives in the water. When it is time to lay their eggs, the females swim to land ...

They usually return to the place where they themselves were born. How they find their way back there is unknown. When they reach shore, the big, heavy turtles crawl slowly up to the high water mark. Using their flippers (脚蹼), they pull themselves along the sand. They must struggle like mountain climbers. When they finally reach dry sand, they rest before beginning the difficult task of laying eggs.

Since the 1970s，scientists have been searching for ways to link the brain with computers. Brain Computer Interface(BCI) technology could help people with disabilities send commands to machines.

Recently，two researchers，Jose Millan and Michele Tavella from the Federal Polytechnic School in Lausanne，Switzerland，demonstrated (展示) a small robotic wheelchair directed by a personˈs thoughts.

In the laboratory，Tavella operated the wheelchair just by thinking about moving his left or right hand. He could even talk as he watched the vehicle and guided it with his thoughts.

“Our brain has billions of nerve cells. These send signals through the spinal cord (脊髓) to the muscles to give us the ability to move. But spinal cord injuries or other conditions can prevent these weak electrical signals from reaching the muscles.” Tavella says. “Our system allows disabled people to communicate with external world and also to control devices.”

The researchers designed a special cap for the user. This head cover picks up the signals from the scalp (头皮) and sends them to a computer. The computer interprets the signals and commands the motorized wheelchair. The wheelchair also has two cameras that identify objects in its path. They help the computer react to commands from the brain.

Prof. Millan，the team leader，says scientists keep improving the computer software that interprets brain signals and turns them into simple commands. “The practical possibilities that BCI technology offers to disabled people can be grouped in two categories: communication，and controlling devices. One example is this wheelchair.”

He says his team has set two goals. One is testing with real patients，so as to prove that this is a technology they can benefit from. And the other is to guarantee that they can use the technology over long periods of time.

Cancer is a leading cause of death around the world.

When it comes to cancer, the sooner you know you have it, the better your chances of surviving are.

A new blood test could change the way doctors and researchers find cancer in patients. Researchers say the test could provide some hints of the early forms of the disease.

Gareth Jenkins is a professor at the University of Swansea. He says he and his team did not look for cancer. They instead looked for a by-product of cancer, mutated (突变的) red blood cells. They looked for, what Jenkins calls, the collateral (附带的) damage of cancer—the damage left by the disease.

“In this blood test we don’t measure the presence of cancer，we measure the presence of mutated red blood cells which are the collateral damage that occurs—a by-product of the cancer developing.’’

The researchers used normal laboratory equipment to perform the tests. This equipment looks for changes in the structure of millions of red blood cells. Those mutated cells lack a surface protein (蛋白质) that healthy cells normally have.

“The goal of the test is looking for very rare cells which have picked up a mutation. The number of mutated red blood cells in a healthy person is around 5 or so mutated cells per million; so, you have to look at millions of red blood cells to discover those rare events. The number increases in cancer patients—it goes up to 40 or 50 on average.”

The researchers tested blood from about 300 people, all of whom have cancer of the esophagus (食管). Patients with esophageal cancer have high levels of mutated red blood cells. Jenkins says that at this point he is not sure if other cancers would produce similar results.

The hope is that the new test could one day become part of commonly used medical methods to find out if a person has cancer. These new technologies could save millions of lives.

Can you imagine what things will be like 50 years from now? You’ll get up in the morning and brush your teeth in front of the bathroom mirror just like today. But one thing will be different: besides showing your image, the mirror might also show news, traffic, videos and weather information.

When you are ready to go to work, your smart car will drive you to your office. It knows the best route to take to avoid traffic. You will be able to check your e-mails on the dashboard (仪表盘). Every car will even be able to “talk” to others to avoid accidents.
  The scenes above aren’t just fantasies. They are the latest concepts and inventions presented at last month’s Mobile World Congress, a yearly trade show held in Barcelona, Spain.
  At the show, people were able to experience new technologies and mobile devices (装置) that are highly likely to enter their daily lives in the near future.
  For example, a new fitting room was introduced that lets you try on clothes virtually. It has 360-degree mirrors that create a 3-D image of you in the clothes, and this image can be sent to your phone for you to decide later which items to buy.On the street, photos of products were placed on posters with NFC tags (标签) – a special code (编码) a bit like a 2-D bar code. You could hold your phone up to the tags to add those items to your shopping basket online, pay for them with your phone and have them sent to your home.  As The Guardian noted, the Mobile World Congress shows how electronic devices are becoming smarter by the day. Soon, you might find yourself asking your washing machine: “How are you getting on?” To which it will reply: “Almost there, sir; I’ll be done in 15 minutes.”

     It’s cold and dark outside，and your bed is so warm and comfortable. Going for a run seems like such a bad idea. But before you hide your running shoes，it might be worth giving that crazy idea a go.

  According to The Huffington Post，an outdoor run in winter, as opposed to one on a treadmill(跑步机)，bums more calories because the body is working hard to regulate(调节)its core temperature. Furthermore, research shows that race times are faster in cold weather than in warmer temperatures-and quicker runs burn more calories. Similarly，cold weather also makes the heart work harder to distribute blood through the body，making that vital muscle even stronger.

Outdoor exercise also turns up your energy and rids you of the stress and depression that build up every day. The heat and humidity in the summer can drag you down and tire you faster, but cold weather is refreshing. It adjusts you to your surroundings，making you feel alive.

Of course，the threat of smog in some built-up areas is a further hurdle to winter exercise. Heart attacks stroke, lung cancer and asthma are all dangers of running in smog. The combination of air pollution and exercise increases the potential problems. If you do choose to run outside on smoggy days, take a path in a park or residential area to avoid car exhaust(尾气) and go early in the morning，before rush hour. But staying inside on smoggy days and waiting for the next clear day to run is best.

How many things can you see in the night sky? A lot! On a clear night you might see the Moon, some planets, and thousands of stars.

But scientists believe there are some things in the sky that we will never see. We won’t see them with the biggest telescope in the world, on the clearest night of the year. That’s because they are invisible. They’re the mysterious dead stars called black holes.

 You might find it hard to imagine that stars die. After all, our Sun is a star. Year after year we see it up in the sky, burning brightly, giving us heat and light. The Sun certainly doesn’t seem to be getting old or weak. But stars do burn out and die after billions of years.

 As a star gases burn, they give off light and heat. But when the gases run out, the star stops burning and begins to die. 

As the star cools, the outer layers of the star pull in towards the center. The star squashes(挤压) into a smaller and smaller ball. If the star was very small, the stars ends up as a cold, dark ball. If the star was very big, it keeps squashing inward until it’s packed together tighter than anything in the universe.  

Imagine if the Earth were crushed(挤压) until it was the size of a tiny marble. That’s how tightly this dead star, a black hole, is packed. What pulls the star in toward its center with such power? It’s the same force that pulls you down when you jump--- the force called gravity. A black hole is so tightly packed that its gravity sucks(卷入) in everything---even light. The light from a black hole can never come back to your eyes. That’s why you see nothing but blackness.  

So the next time you stare up at the night sky, remember: there’s more in the sky than meets the eye! Scattered(散落) in the silent darkness are black holes--- the great mystery of space.