We all have different ways to navigate (导航) when lost—whether asking a stranger for help, consulting an old-school map or simply following our nose. But on a bike, the risks are higher. One wrong turn or that you're in a traffic jam with two lanes between your bike and the nearest pavement may ruin your good mood. Although cyclists, of course, managed to navigate before smart phones, cyclists can make two choices: a few stay calm and embrace getting lost, and the rest turn to a navigation app.

    Google Maps added a directions function for cyclists in 2015 in the US and Canada, and two years later across Europe. And while there are dozens of other apps now offering a similar service, Google Maps has the demerits for many, so the app seems to be falling behind expectations.

    As someone with no sense of direction, I knew it wouldn't be easy when I started cycling earlier this year. I appreciated that the app gave me two warnings before I needed to turn off a road, and automatically recalculated my route if I accidentally went off course. But still, it wasn't a smooth process. Google Maps thought I could cut across a double carriageway with no breaks in its barrier, assumed I knew what it meant when it told me to “head west”, and thought nothing of taking me the wrong way down a busy one-way street.

    Cyclists don't just want safety—they want convenience. Londoner Robson Smith regularly cycles between Clap ham and the City of London and would like to see Google Maps calculate routes where his bike is allowed on public transport and more choice of the type of routes he can take. “Google tends to calculate the most common and comfortable cycle routes. It would be better to have an option which included the fastest route, regardless of comfort,” he says.

    For this reason, Robson says he uses the app Cycle Streets instead. It offers a choice of four different route modes, based on the type the user wants, and saves previous routes. It also tells you how many calories a route burns, how many traffic lights you wilt encounter, and how busy it is.

    In modem times, many teenagers have idols of their own who are always some stars on TV on the Internet, etc. These stars always think that a slimmer figure may be perfect for themselves. However, does size really matter? Are teenage fans trying hard to become like their idols? Do famous stars really have the power to influence people especially teenagers?

    For the longest time, many parents blame (责备) teen idols for influencing the way their kids act. Have you noticed how teens idolize the stars these days? Even, their personal affairs are being followed by kids these days. Take for example the case of Lindsay Lohan or Mary Kate Ashley, They are definitely famous teen stars. However, since they are trying to project an image to satisfy a lot of people in show business their health and body suffer. Many kids are aware of this problem. But they are easily influenced by these stars to exercise and eat less.

    It is a fact that the media and especially famous teen stars can influence people powerfully. But teenagers are easily influenced because teenage years are the period when our personality and identity developments take place. Teens watching TV shows and reading magazines are easily pulled into the dieting and harmful eating habits because the media have some ways to pull these acts. They use thin models and stars to endorse (宣传) products or to star in an up-and-coming shows or movies. With fierce competition, stars are forced to eat less and do extreme exercise routines to get the roles or offers that come their way.

    Living in today's time and generation is a bit disturbing to a lot of parents. Media, especially as well as the stars, have a very powerful influence to drive teenagers to good or bad. It's good that we can control ourselves to avoid bad things from happening. If not, parents should really be aware and guide their teens to determine what's in and what's out.

    About ten men in every hundred suffer from color blindness in some way. Women are luckier; only about one in two hundred is affected in this matter. Perhaps, after all, it is safer to be driven by a woman!

    There are different forms of color blindness. In some cases a man may not be able to see deep red. He may think that red, orange and yellow are all shadows of green. Sometimes a person cannot tell the difference between blue and green. In rare cases an unlucky man may see everything in shades of green — a strange world indeed.

    Color blindness in human beings is a strange thing to explain. In a single eye there are millions of very small things called "cones". These help us to see in a bright light and to tell difference between colors. There are also millions of "rods", but these are used for seeing when it is near dark. They show us shape but no color.

    Some insects have favorite colors. Mosquitoes prefer blue to yellow. A red light will not attract insects, but a blue lamp will. In a similar way human beings also have favorite colors. Yet we are lucky. With the aid of the cones in our eyes we can see many beautiful colors by day, and with the aid of the rods we can see shapes at night. One day we may even learn more about the invisible colors around us.

    The smallest kids on Earth are much smaller than you or your baby brother or sister. They're even smaller than the hairs on your head. We call them “NanoPutians”(纳米小人). Also known as NanoKids, the NanoPutians aren't real people. They are actually tiny molecules (分子) made to look a little bit like people.

    James Tour invented the NanoPutians as a way to teach kids about nanoscience, which refers to the study of things that are smaller than about 100 or 200 nanometers. “The exact size is less important than the possible applications of working with such tiny things,” Tour says, “Nanoscience is the study and development of the small so that it will affect the large.”

One of the goals of the research is to control individual atoms. Carbon, hydrogen, oxygen, and other types of atoms are the building blocks of the universe. They make up planets, rocks, people, trees, CDs — all the stuff out there. “Most things that people build come together in a top-down way”, Tour says. If you want to make a table, for instance, you cut down a big tree, make wooden boards, and hammer them together. Nature, on the other hand, builds things from the bottom up. When atoms join together they make molecules. Each molecule has a certain shape, and a molecule's structure determines what it can do. Molecules can make them come together to make a cell — or a tree.

    Tour and his co-workers turned these molecular structures into cartoon figures and made an animated(动画的) science video about the little people, set it to music and started showing it to kids in school while talking about how exciting research on small things can be.

    “Learning about the NanoKids has opened up a world of possibility for real kids who ordinarily would rather not study biology, chemistry or physics.” Tour says. When you look closely enough, the really small can be really cool.

    Teenagers who spend hours in front of the television may have a poorer diet as young adults.

    A study, which included nearly 1, 400 high school students, found those who watched TV for five hours or more per day had less healthy diets than peers (同龄人) five years later. Why does this happen? Should the parents take any measures?

    On the one hand, people who spend a lot of time in front of the TV, especially teenagers, may snack more, and that may affect their long-term diet quality.

    On the other hand, TV ads for fast food, sweets and snacks tempt teenagers to eat more of those foods. And TV time might also replace exercise time for some kids.

    Lead researcher Dr. Daheia J. Barr-Anderson, of the University of Minnesota in Minneapolis, told Reuters Health a clear correlation between TV time during high school and diet quality in young adulthood. While the heaviest TV viewers were eating the most junk food, those who'd watched less than two hours per day had the highest intake (吸收) of fruits, vegetables, whole grains and high-calcium food. In her opinion, parents should limit and monitor TV viewing.

    As far as I am concerned, children should watch no more than two hours of television per day. And parents should set a good example by eating right, being physically active and curbing their own TV time.

    You can't see your sleeping pets brain waves, but its behavior can tell you when your cat might be dreaming. If you watch closely, you'll see that as she falls asleep, her breathing becomes slow and regular with 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 eyes move under her closed lids, her paws twitch (抽动) and she flicks (尤指用手指或手快速地轻抚) an ear. She has entered dreaming. Although she twitches and makes little grunting (嘟嘟) 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 (麻痹)".

    Michel Jouvet, a French scientist, interrupted their sleep paralysis. Even though they were completely asleep, the dreaming cats began to run for balls that Jouvet couldn't see and arched (弓起) their backs at unseen enemies. He figures he was watching them act out their dreams! Obviously, the dreaming cats seemed to be practising important cat skills: following, pouncing (猛扑), and fighting.

    In another study, 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 caning. 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. How often animals dream seems to be tied to body size. Cats dream about every 15 minutes, mice every 9 minutes, and elephants every 2 hours. And though cows and horses usually sleep standing up, they only dream when lying down.