2 . You can't see your sleeping pet's brain waves, but its behavior can tell you when Fido or Fluffy might be dreaming. If you watch closely, you'll see that as your cat falls asleep, her breathing becomes slow and regular and her body still. She has entered the first stage of sleep, called slow-wave sleep. After about 15 minutes you'll notice a change in her breathing. Her paws and whiskers twitch(抽动) and she flicks an ear. Fluffy has entered REM(Rapid Eye Movement), or dreaming stage of sleep. Although she twitches and makes little grunting noises, messages from her brain to the large muscles in her legs are blocked, so she can’t run about. She is in a state of “sleep paralysis”.

Back in 1963, Michel Jouvet, a French scientist who was studying sleep in cats, interrupted their sleep paralysis. Even though they were completely asleep, the dreaming cats began to chase balls that Jouvet couldn't see and arched their backs at invisible enemies. He figured he was watching them act out their dreams!

What were they dreaming about? Mostly, the dreaming cats seemed to be practising important cat skills: stalking, pouncing and fighting.

In another study, neuroscientist Matt Wilson recorded rats' brain waves while they learned mazes(迷宫). One day, he left the brain-wave-recording machine on while the rats fell asleep. The pattern of brain waves in the sleeping rats matched the pattern from the maze so closely that Wilson could figure out exactly which part of the maze each rat was dreaming about!

Many researchers now think that in both people and animals, one purpose of dreams is to practise important skills and figure out recent learning. This may explain why so many people dream about fighting and escaping, skills that were probably important to our ancestors, and why dreaming affects our ability to learn.

Do all animals dream? From looking at the brain waves of sleeping animals, scientists think that all mammals dream, but reptiles, fish, and invertebrates(无脊椎动物) don't.(They're not sure about birds.)

6 . When I was 6, my elder brother brought me to the local BMX(自行车越野) track to ride in a kid’s race for the first time. The hill out of the starting gate looked so scary and step that I backed off. My parents took me back for another try the next week. I fell almost immediately but still managed to win the second place. I’ve loved racing ever since.

I turned pro at 15, which isn’t possible now: You have to be 17 to compete professionally around the time I went pro, BMX became an Olympic sport and I decided to pursue it after high school. I’m the youngest woman with a professional title in the United States.

BMX isn’t judged on tricks or how you handle barriers, but it’s an extreme sport. It’s like horse racing mixed with riding a roller coaster. It starts with a huge burst of speed—I go 40 mph by the time. I’m two and a half seconds out of the gate. Then I try to come out in front of seven competitors at the end of the track, which includes 40-foot jumps. I keep chasing the high that comes from prestart nervousness, big jumps, and that feeling of crossing the finish line first.

Strength and balance are key in competition, so I work out at least five days a week to prepare. I do tons of resistance and agility(灵活) training, both on and off the bike. I also do mental drills with a sports psychologist to make sure I’m focused and confident going into competition. If I make a mistake on the course, I have to move on. Everyone is out to beat me; I need to concentrate on winning so my competitors can’t capitalize on an error and pass me!

I was so proud to win a silver medal at the Olympics in Rio, but I felt I was capable of gold, so that will push me to do better. I’m continually working to reach my potential in the sport. Until I feel completely satisfied, I’ll keep coming back.

7 . On a break from his studies in the MIT Media Lab,Anirudh Sharma traveled home to Mumbai, India. While there, he noticed that throughout the day his T-shirts were gradually gathering something that looked like dirt."I realized this was air pollution，or sooty（像煤一样）particulate matter (PM)，made of black particles released from exhaust（尾气）of vehicles，" Sharma says. "This is a major health issue."Soot consists of tiny black particles, about 2.5 micrometers or smaller, made carbon produced by incomplete burning of fossil fuels.

Back at MIT,Sharma set out to help solve this air-pollution issue. After years of research and development, Sharma’s startup Graviky Labs has developed technology that attaches to exhaust systems of diesel generators（柴油发电机）to collect particulate matter.Scientists at Graviky then turn it into ink, called Air-Ink, for artists around the world. So far, the startup has collected I.6 billion micrograms of particulate matter.More than 200 gallons of Air-Ink have been harvested for a growing community of more than 1,000 artists, from Bangalore to Boston, Shanghai,and London.

Posted all over Graviky Lab's Facebook page today are photos of art made from the Air-Ink and pant, including street wall paintings, body art and clothing prints.At first, there was still no specific application for the ink. Then the startup decided to find new ways to further spread its mission.It chose to do so through art."Art helps us raise awareness about where the ink and paint comes from. Air pollution knows no borders. Our ink sends a message that pollution is one of the resources in our world that's the hardest to collect and use.But it can be done,"Sharma says.

8 . How many phone numbers can you remember by heart? It’s probably fewer than you would like. Actually, you’re not alone. Out of more than 1,000 Americans who were surveyed, more than half said that they couldn’t recall the phone numbers of their friends and neighbors. And 44% said that they couldn’t remember their relatives’ phone numbers. In their eyes, there is no point in filling their heads with phone numbers if they’re all stored in smart phones that are with them almost all the time.

In fact, most people are suffering from a sort of digital amnesia. More than 90% of those surveyed agreed that they used the Internet as an online extension of their brains. Rote memorization was once an important part of modern education, but we just need a click or slide now. That’s making us worse at remembering things.

Researchers found that when people expected to have access to information online, they were less likely to remember actual facts，but more likely to remember how to find them. As a result, we are already becoming one with our computer tools, growing into interconnected systems that remember less by knowing information than by knowing where the information can be found.

However, some believe it isn’t necessarily a bad thing—maybe it gives them more chances to think through things. We certainly have access to more knowledge now than ever, even if it isn’t all stored in our brains.

Even so, I still believe that there are more risks to this new world of memory beyond losing our ability to recall some information such as who the 15th President was. That kind of information may always be a click away, but the important things are personal ones, like the way your parents smiled at your wedding. It’s harder to recall or find online. If you’re relying on yourself to keep track of those memories, they will be much more meaningful.

9 . Animals in the Arctic, including reindeer and golden eagles, are migrating earlier due to climate change, say researchers who have gathered a huge amount of data to study the behavior of 86 Arctic species over the past three decades.

“We have the ability to keep our eyes on animal movements on a very large scale,” says Eliezer Gurarie at the University of Maryland. “It seems that animals are unknowingly reacting and adapting to climatic changes, and have been doing for years.”

Gurarie and his team used GPS and satellites to track the spring migration of more than 900 female reindeer over the past 15 years. They discovered that the females are migrating to give birth about a day earlier year on year, probably as a result of warming temperatures. Earlier birthing times can be risky in northern parts of the Arctic, says team member Gil Bohrer at Ohio State University. “There are higher chances of their children facing strong and unexpected storms,” he says. If they do, many will die because they cannot deal with extreme conditions.

Similarly, golden eagles — which usually nest in the Arctic area — have been starting their spring migration half a day earlier each year over the past 25 years.

“The day-to-day change of climate is very small,” says Bohrer. “To understand how animals react to climate change, you need a very long period of observation — something that has only recently been possible.”

The researchers’ archive of Arctic animal movement currently covers more than 15 million data points related to 8000 animals. “Our archive can help to advise management methods to preserve endangered species, as climate change only becomes more extreme,” says Bohrer.

10 . What limits you from hiking more often? Many complain that they don't have a suitable partner to go with. Why not take a look at the great hiking clubs across Canada?

• Yukon Outdoors Club

Website: yukonoutdoorsclub.ca

Membership cost: $10 for a single membership; $15 for a family membership

Description: The club arranges day hikes, backpacking trips, canoe trips, mountain biking, cross-country skiing trips, snowshoeing trips and various workshops for members to gain new skills and valuable information.

• UBC Varsity Outdoor Club

Website: ubc-voc.com

Membership cost: Students $40； non-UBC students $60

Description: The UBC Varsity Outdoor Club is a social group that hikes, mountaineers, rock climbs and ice climbs. Travel and outdoor-minded UBC students and non-students are welcome to join. The UBC VOC has also constructed a few backcountry cottages in the Coast Mountains.

• Pender Harbor Hiking Group

Website: penderharbourhiking.weebly. Com

Membership cost: Free.

Description: The Pender Harbor Hiking Group offers hikes scheduled two months in advance, so get on the mailing list or check the website regularly to find a hike that's right for you! Hikes are usually one and a half to two hours long, but some full-day hikes are scheduled, depending on members, interest.

• Vernon Outdoors Club

Website: vernonoutdoorsclub. Org

Membership cost: A single membership is $25, and students pay $10, Children are free.

Description: Boasting a membership of close to 200 people, the Vernon Outdoors Club is an active group that enjoys hiking and cycling. The group organizes a Tuesday Rambles event each week and also hosts multi-day trips.