The chaparral ecosystem is a plant and animal community that is relatively rare. It is characterized by shrub­land and a specific weather pattern. Winters in this ecosystem are mild and wet, and summers tend to be hot and dry. The state of California in the United States has one of the world's largest chaparral ecosystems. They can also be found in parts of northern Mexico, Australia, Chile, and South Africa.

Wildfires occur frequently in this ecosystem. Lots of very flammable plant growth builds up in between fire seasons. Only about 15­39 inches of rainfall each year. Shrub plants of the chaparral are most likely to catch fire in the late summer or early fall. That's because the summers are extra dry. The thought of fire is frightening to people with homes or businesses. However, it is far more dangerous not to have wildfires. When there are no fires, the shrubs take over. Small fires once in a while are beneficial. They keep the plant growth under control. They also act in some other surprising ways. There are some plant species in chaparral ecosystems that cannot reproduce unless there has been a fire. The heat, smoke and changes in the soil that follow a burn actually release seeds from some plants.

What causes the frequent fires in this region? Sometimes lightning strikes will catch plants on fire. However, this accounts for only a small portion of the fires. Humans are the cause of many wildfires. A match, cigarette or campfire left carelessly unattended can cause a fire. Hot, dry winds, like the Santa Ana winds in California, make the fire go wild.If it has been a long time since the last fire, plants will fuel the fire. It is often very difficult for firefighters to put out these fires.

People who live in and near chaparral ecosystems have to clear plants from around their homes. This helps to prevent the home from being damaged in a fire. Wildfires are a natural and important part of a healthy chaparral ecosystem.

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 a small robotic wheelchair directed by a person’s 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.

The Mangrove Rivulus, a type of small killifish, lives in small pools of water in a certain type of empty nut or even old beer cans in the mangrove swamps of Belize, the United States and Brazil. When their living place dries up, they live on the land in logs (圆木), said Scott Taylor, a researcher at the Brevard Endangered Lands Program in Florida.

The fish, whose scientific name is Rivulus marmoratus, can grow as large as three inches. They group together in logs and breathe air through their skin until they can find water again.

“We kicked over a log and the fish just came crowding out.” Taylor told Reuters in neighboring Guatemala by telephone. He said he will make his study on the fish known to the public in an American magazine early next year.

In lab tests, Taylor said he found the fish can live up to 66 days out of water without eating.

Further studies of the fish may tell how animals changed over time.

“These animals live in conditions similar to those that existed millions of years ago, when animals began making the transition (过渡) from water onto land,” Wright said.