Back in 1963， a company in the US was suffering from low employee（员工） spirit． Everyone was worried that they might lose their jobs， since the company had just joined up with another company， which meant there were suddenly more employees than needed．

That was when Harvey Ball（1921﹣2001）， an artist， was invited by the company to find a way to raise the workplace's spirit． It took Ball less than 10 minutes to draw a smiley face on a bright yellow background， which was then made into buttons that employees could wear on their jackets as a reminder to smile at each other． The face soon became part of the companies culture and was introduced across the country， and﹣ before Ball realized it﹣to the world．

However， as much effort as Ball made， that "message"soon grew to become twisted（歪曲的）． Just think about it： How many of us still use the simple smiley face emoji just to say， "I'm smiling "？ Chances are when we use it， we often mean， "I'm just going to ignore you or"That' s just perfect"﹣ in a sarcastic（讽刺的）way． And our favorite emojis perhaps also include the upside﹣down face or the face with tears of joy ﹣both changed from Ball's former smiley face﹣ and yet， both are often used sarcastically．

Indeed， in today's world， we deal with many things with sarcasm instead of with a smile， perhaps because were finding it harder and harder to be happy． but we keep forgetting about the fact that happiness and smiling go both ways． As Vietnamese spiritual teacher Thich Nhat Hanh once said， "Sometimes， your joy is the source of your smile． But sometimes， your smile can be the source of your joy That was probably what was in Balls mind when he first came up with the smiley face： A smile brings joy， and joy brings people closer together．

Time is time， no matter where we are in the world． However， it seems like whenever we wait for a friend to get ready， five minutes can seem like a whole day． And meanwhile， a really interesting two﹣hour movie may feel like it only lasted a few minutes． So， how is it that time doesn't always seem to follow the same rules？ What actually affects（ 影响）our feeling of time？

According to a new study published in the journal Nature in August， the differences in how we sense time come from a"clock？ inside our brain． However， the brains clock， controlled by a network of brain cells， gets its sense of time from our experiences and memories， reported Medical News Today． So， unlike regular clocks， our brain forms a " subjective（主观的） time coming from the ongoing flow of experience，" Edvard Moser， director of the Kavli Institute based at the Norwegian University of Science and Technology， explained in Neuroscience News．

To examine the activity of this network， a team of scientists at the Kavli Institute studied the brain activity of rats for several hours， during which time the rats were required to complete a series of activities． According to Neuroscience News， it was found that when the rats carried out any repetitive（重复的）activities， the brain network became more precise． It matched the actual time of day． On the other hand， when they took part in any exciting experiences the brain network didn't rely on real time markers． This led to time passing unconsciously（无意识地）．

According to Moser， to speed up or slow down the brain's clock depends on whether the brain simply judges time based on experiences it processes（加工）． "If we change what we are doing， we also change our experience of time， he told the Norwegian Broadcasting Corporation． " It's not about clock time but about our subjective feeling of time．

One day， we were hiking in the Oakland woods when my daughter noticed plastic litter in a stream． She looked at me and said， "Daddy That doesn't go there． "

What she said brought me back to a summer camp． On the morning of a visiting day， right before they let our anxious parents come running through the gates， our camp director would say，"Quick! Everyone， pick up five pieces of litter． You get a couple hundred kids each picking up five pieces， and pretty soon， you've got a much cleaner camp．

So I thought， why not use that crowdsourced tidying model to the entire planet？ And that was the inspiration （灵魂）for Litterati． The goal is to create a litter﹣free world． Let me show you how it started． I took a picture of a cigarette using Instagram． Then I took another photo……and another photo．

And I started telling people what I was doing， and they started to join． We were becoming a community（共同体）that was collecting photos． Each photo tells a story． It tells us who picked up what and when． So I built a Google map， showing where pieces were being picked up． And gradually， the community grew and the Literati grew．

If you really want to create change， there's no better place to start than with our kids．

A group of fifth graders picked up 1， 247pieces of litter just on their schoolyard． And they learned that the most common type of litter was the plastic straw wrappers（包装纸）from their own dining hall． So these kids went to their headmaster and asked， "Why are we still buying straws？"And they stopped． And they learned that separately they could each make a difference but together they created an influence．

It doesn't matter if you're a student or a scientist， whether you live in Honolulu or Hanoi this is a community for everyone．

After too many "Ill start next Mondays"， you finally decide to start your clean eating plan．    11    Here are some top tips to help you beat the food temptation（诱惑）and keep healthy．

Keep your goal in mind

Some people go as far as to suggest sticking a picture of your ideal body on your fridge． If that can work for you， go ahead．    12    Keep your goal in mind． Remember that the choices you make today will decide how your body looks and feels．

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This doesn't mean eating a cheat meal or the chocolate you have been dreaming of． Try connecting rewards with non﹣food items rather than junk food． Reward your fitness exercise and clean eating with dancing， singing Karaoke or new jeans to go with your new figure．

Start small．

We've heard that Rome wasn't built in a day． We should follow the same principle when it comes to dropping weight or eating clean．    14    By the end of the year， you would have made around fifty small changes that's more than enough to equal big results．

Prepare healthy snacks

    15    Have healthy snacks such as a small tub of blueberries， nuts， apple slices with nut butter， julienne carrots， or other vegetables within easy reach．