Climbers at Qomolangma are being asked to clean up after themselves.

Qomolangma has earned the nickname（绰号）the Worldˈs Highest Garbage Dump（垃圾场）.

Climbing Qomolangma,the worldˈs highest mountain,just becomes more challenging.The government of Nepal is telling climbers they cannot leave trash on the trails.Each climber will have to come down the mountain with at the least 18 pounds of garbage.Thatˈs the average amount of trash a climber leaves behind on Qomolangma.

Officials say climbers are responsible for their own trash.“We are not asking climbers to pick up trash left by someone else,”said the Nepal Tourism Ministry.“We just want them to bring back what they took up.”

More than 4,000 people have reached the 29,035-foot summit（顶峰）in more than 60 years.Leaving trash along the way helps climbers keep their bags light so they have energy to reach the summit.“The trash problem in Qomolangma is not new.”Burlakoti says.“When the people started to climb the mountain,they started to leave their garbage there.”They have left behind bottles,food boxes and equipment.

The new rule came into effect in April,2014.To make sure it is followed,climbers will have to deposit money（交保证金）before they climb.Once they climb back down the mountain,officials will check climbers at a return camp to make sure they have the required 18 pounds of trash.If they do,their money will be returned to them.If they do not,climbers will not receive their deposit and they will not be given a permit the next time they want to climb Qomolangma.

The goal is to make sure no more litter will be left on Qomolangma."As we offer Qomolangma to all the people of the world they should take responsibility to clean it."Burlakoti says,“After seeing the results from this,we will also apply this rule to other mountains.”

Why do men die earlier than women? The latest research makes it known that the reason could be that men’s hearts go into rapid decline when they reach middle age. The largest study of the effects of ageing on the heart has found that women’s longevity(长寿) may be linked to the fact that their hearts do not lose their pumping power with age.

“We have found that the power of the male heart falls by 20-25 percent between 18 and 70 years of age,” said the head of the study, David Goldspink of Liverpool John Moores University in the UK.

“Within the heart there are millions of cells that enable it to beat. Between the age of 20 and 70, one-third of those cells die and are not replaced in men,” said Goldspink. “This is part of the ageing process.” What surprises scientists is that the female heart sees very little loss of these cells. A healthy 70-year-old woman’s heart could perform almost as well as a 20-year-old one’s.

“This gender difference might just explain why women live longer than men,” said Goldspink.

They studied more than 250 healthy men and women between the ages of 18 and 80, focusing on healthy persons to remove the confusing influence of disease.

The team has yet to find why ageing（衰老）takes a greater loss on the male heart, said Goldspink.

The good news is that men can improve the health of their heart with regular exercise. Goldspink stressed that women also need regular exercise to prevent their leg muscles becoming smaller and weaker as they age.

One night, Pilar was in a deep sleep when she was woken by her cat Inti. Inti was meowing wildly outside Pilar’s bedroom and throwing himself against the closed bedroom door. When Pilar opened her eyes, she saw that her bedroom was filled with smoke. As she escaped her house with Inti in her arms, she saw that a fire was burning in her kitchen. Pilar could easily have lost her life, but Inti would not let that happen. Even though Inti could have escaped the house through a cat door, he wouldn’t leave Pilar.

As amazing as this story is, it is not as uncommon as you may think. Take the example of Charlotte Lee and her horse, Thunder. One summer night, the whole family was asleep with the windows open. It was normally very quiet where they lived. Suddenly, there was a loud noise. Charlotte woke up from her sweet dream, and the noise continued. Then she heard a horse running fast towards the house. The next thing she saw was Thunder standing outside her window, neighing(嘶叫) and shaking his head. She knew something was wrong. Charlotte quickly got everyone out of the house before the earthquake hit. Thunder has saved her life.

There are also stories of wild animals coming to the rescue of humans. One animal known to be a friend of humans is the dolphin. Once, Todd Endris was surfing with his friends when he was attacked by a 13-foot(4-meter) shark. In the middle of the attack, a group of dolphins came to his rescue by forming a protective ring around Endris until he could get safely to shore. Without the help of the dolphins, there is little chance that Todd could have escaped.

No one is sure why animals have so often come to our rescue. However, it is clear that humans and animals enjoy a close relationship. It is important that we care for them as much as we can.

Are you sick of going to bed late and waking up tired? Then grab your hiking boots and a tent. A new study suggests that camping in the great outdoors for a couple of days can reset your body clock and help you get more sleep.

The body clock is an internal system that tells our bodies when it’s time to go to sleep and when it's time to wake up. Scientists track this clock by measuring the amount of melatonin (褪黑激素)circulating in a person’s blood at any given time.

In a healthy sleeper, melatonin levels rise a few hours before bedtime, stay high through the night, and then settle back down when it’s time to wake up.

In our modern society，however，most of us stay up many hours past sunset and would probably sleep in many hours after sunrise if we could. And the trouble is，your melatonin levels may still be high when your alarm clock goes off in the morning, which leads to fatigue. It may also have other health consequences as well, such as diabetes (糖尿病)，overweight and heart disease.

Professor Kenneth Wright of the University of Colorado in the US wanted to see if our body clocks can be reset by a short stay in nature. His team recruited (招募)fourteen physically active volunteers in their 20s and 30s. Nine went on a weekend camping trip, while the other five stayed home. At the end of the weekend, the researchers reported that in just two days, the campers’ body clocks had shifted so that their melatonin levels began to rise more than an hour earlier than they did before they left on the trip. By contrast, the body clocks of the group that stayed home shifted even later over the course of the weekend.

“This tells us we can reset our clocks fast,” Wright said.

Therefore, if you want to change your sleep patterns you could try to increase your exposure to natural light during the day and decrease the amount of artificial light you see at night. And if that doesn’t work，there’s always camping.

Twelve years ago, a young traveler named Rhett Butler fromSan Francisco,California, visited theSabahrainforest on Malaysian Borneo. In the rainforest, he watched a bird flying through the trees. The beautiful sight left quite an impression on him. But weeks later, back home, Rhett Butler got the news that trees in the area he visited had been cut down.

That experience led Rhett Butler to write a book about rainforests and threats to their existence. But he did not publish the book. Instead, he created a website, using his research for the book. The site is Mongabay.com. His purpose was to inform the public of tropical rainforests. But the subject quickly developed. As a former businessman, he became a respected writer of science and environmental stories.

The popularity of Mongabay.com attracted advertisers. Small ads on the site pay for its operations. Mongabay.com has grown and led to other sites, for example, kids.mongabay.com, a site for children; WildMadagascar.org, which is about the island that Rhett Butler called his favorite place.

To keep his website going, he travels around the world on several major trips each year. His working tools are a laptop computer, cameras and some diving equipment. He often calls on experts for information. For example, he interviewed Alison Jolly, a top expert on lemurs (狐猴). He interviewed Rodney Jackson, a biologist who established the Snow Leopard Conservancy (雪豹保护协会).

Stories like these have made Mongabay a favorite place on the Internet for researchers, students and teachers. In April, Time.com named it one of the fifteen top climate and environment websites in the world.