For as long as I can remember, I've always wanted a personal motto. I wanted a saying that I could really try to live my life by. I mean all the humorous book and storybook heroes always have a personal principle they follow. Good manners! Courage! Keenness! But a part of me could never get myself to create my own motto because I never knew where to start and I never thought I could give one.

    “With great power comes great responsibility.” is a quote by the great writer and philosopher, Voltaire. More familiar, it makes an appearance in the modern day movie performance of the superhero Spider-Man. This saying provides a sense of responsibility for those with actually limitless power.

    “Be good to others and others will be good to you.” is another well-known proverb that has roots in almost all of the major religions. Although it is less practiced today than it is lectured, it is a powerful and good motto to live by. Kindness, in this sense, is the final power in judging every action.

    My personal motto today has an idea – being efficient. Through my limited knowledge, I have come to find that this is simply the best way for me to give insight about who I am and what I believe in.

 Efficiency is a quality that everyone desires for, right? Who doesn't want to be able to not only work fast but to achieve great results? To some, it may appear to be a frightening journey. But to me, it means that I have a lifelong journey to improve the methods and ideas with which I come near my tasks.

    Regardless of what motto you want to live by, I believe that everyone should have one, or two or more. These are all symbols of a perfect story of us, in our own view. And it immediately provides insight to the type of person we were, we are and what we strive to be. We are never meant to be perfect, but it is important to try and live by a belief that will help us reach our potential. All you have to do is know what your excitement is and live by it.

    There is one type of illness in the world that has a severe effect on more people than anything else and is very deadly. If untreated, this illness could affect everything you do. What is this illness? Depression. Serious depression requires professional treatment. Self-induced depression is something each of us can change.

    Everyone's circumstances are different, but the causes of self-induced depression are common: low self-esteem, hurtful thinking and a bad attitude.

    So how can we change the way we think, feel, and have a cheerful attitude?

    First we must look at ourselves, truly and honestly examining our motives for what we wish to accomplish. If you are dissatisfied because you feel you haven't or can't do anything, then one step is needed—to set goals.

    Always start your goals relatively small and easy to attain. Think of them as sand; one grain may be insignificant(微不足道的) but as a group they form the beach. Once you have set and attained small goals for yourself, move on to slightly larger, more challenging goals.It takes not just setting goals but positive thinking. How can we obtain this?

    There are a number of factors that can make us think negatively and one of those is diet.In my opinion, a person who eats a lot of take-out and fast food is feeding their body junk. Start by eating better foods which give the body much NEEDED minerals. If your physical body is happy, it's much easier for your mental body or “thinking ability” to be happy.

    Next, exercise. Half an hour a day is recommended for positive well-being. Then think about good memories you had, or generally think of things that make you smile. Remember, everything you wear costs money but to wear a smile is free. A smile can be the difference between an average day and a great day.

    If you follow these steps, positive change is on the way.

    French writer Frantz Fanon once said: "To speak a language is to take on a world, a culture." Since the world changes every day, so does our language.

    More than 300 new words and phrases have recently made it into the Oxford Dictionary Online, and in one way or another they are all reflections of today's changing world.

    After a year that was politically unstable, it's not hard to understand the fact that people's political views are one of the main drives of our expanding vocabulary. One example is "clicktivism", a compound of "click" and "activism". It refers to "armchair activists" -- people who support a political or social cause, but only show their support from behind a computer or smart phone.

    "We had all the words around Brexit (脱欧) in the last update and we are now starting to see all the words around Trump coming into the dictionary," Angus Stevenson, Oxford Dictionaries' head of content development, told The Guardian.

    Lifestyle is also changing our language. For example, "fitspiration -- a compound of fit and inspiration -- refers to a person or thing that encourages one to exercise and stay fit and healthy. The phrase "climate refugee" -- someone who is forced to leave their home due to climate change -- reflects people's concern for the environment.

    According to Stevenson, social media was the main source for the new expressions "People feel much freer to coin their own words these days." he said.

    But still, not all newly- invented words get the chance to make their way into a mainstream dictionary. If you want to create your own hit words, Angus Stevenson suggests that you should not only make sure that they are expressive and meaningful, but also have an attractive sound so that people will enjoy saying them out loud.

    Argument for awards

    It's always exciting every year in October when the Nobel Prizes are announced. We get to witness the acknowledgement (表彰) of some of humankind's greatest minds in six fields – literature (文学), medicine, physics, chemistry, economics and activism for peace.

    This year, however, part of the excitement will be taken away, since there won't be a Nobel Prize in literature due to the fact that the Swedish Academy – the institution (机构) that awards the prize – was involved in a sexual harassment scandal.

People worry that a scandal like this will affect the reputation of the Nobel Prizes. But at the same time, we have to ask ourselves whether we really need these awards after all.

    According to Jana Gallus, an economist from the University of Zurich, Switzerland, one of the reasons that people give out awards is to establish a legacy (遗产). In the case of the Nobel Prizes, they encourage people to achieve more by acknowledging the hard work of top figures in different fields.

    Awards may also help establish standards of what's considered high quality. For example, if you're having a hard time deciding which movie to watch, one of them having an Oscar under its belt will probably help you to make your mind up. And by reading the books that have won The Man Booker Prize or listening to songs that have been awarded a Grammy, you get an idea about what “great” literature and music look and sound like – at least in the eyes of judging panels (评审团).

    Sure, awards can backfire. There was the OscarsSoWhite movement in 2015 and 2016, when it turned out that all 20 actors nominated (提名) for two years in a row were white. There was also the GrammysSoMale movement in January, when Alessia Cara was the only woman to win a solo Grammy this year. But still, it was these incidents that brought the problems of racism (种族歧视) and gender (性别) inequality into the public eye once more. And with influential voices – like that of black actor Will Smith, who refused to attend the Oscars ceremony – the problems became more likely to be noticed and dealt with instead of being buried silently, again.

    Maybe these awards do matter, and we do need them – just not while they are under the shadow of a sexual harassment scandal.

    So when it comes to this year's Nobel Prize in Literature, I'm going to have to say: "No, thanks."

    BY CHEN XUE, 21ST CENTURY TEENS STAFF

    City trees grow faster and die younger than trees in rural forestry, a new study finds. Over their lifetimes, then, urban trees will likely absorb less CO₂ from the air thah forest trees.

    As we all know, the earth would be freezing or burning hot without CO₂. However, CO₂ is a greenhouse gas, meaning it traps energy from the sun as/heat. That makes temperatures near the ground rise. Human activities, especially the widespread burning-of fossil(化石)fuels, have been sending extra greenhouse gases into the air. This has led to a rise in average temperatures across the globe.

    Studies had shown forests readily absorb CO₂, but there hadn't been much data on whether city trees grow, die and absorb CO₂ at the same rate as forest trees do. So some researchers decided to find out.

    To figure out how quickly trees were growing, researchers tracked their diameters (the width of their trunks) between 2005 and 2014. A tree's diameter increases as it grows, just as a person's waist size increases as they gain weight. About half the weight of a tree is carbon, research has shown. Most of the rest is water. Over the nine years' tracking, the researchers found city trees absorbed four times as much carbon from the air as forest trees. However, they were twice as likely to die. So over the lifetime of each type of tree, forest trees actually absorbed more CO₂.

    City trees grew faster because they had less competition for light from their neighbors. In a forest, trees tend to grow close together, shading their neighbors. Street trees also benefit from higher levels of nitrogen (氮)in rainwater. Nitrogen helps plants grow. Waste gases from gas-burning cars also contain nitrogen, thus enriching city air with nitrogen. Later, rainwater may wash much of it to the ground. Some street trees may also have better access to water than trees in the country because the underground water pipes can leak.

When I teach research methods, a major focus is peer review. As a process, peer review evaluates academic papers for their quality, integrity and impact on a field, largely shaping what scientists accept as "knowledge"- By instinct, any academic follows up a new idea with the question, "Was that peer reviewed?"

Although I believe in the importance of peer review and I help do peer reviews for several academic journals-I know how vulnerable the process can be. 

I had my first encounter with peer review during my first year as a Ph. D student. One day, my adviser handed me an essay and told me to have my -written review back to him in a week. But at the time, I certainly was not a "peer"--I was too new in my field. Manipulated data （不实的数据） or substandard methods could easily have gone undetected. Knowledge is not self-evident. Only experts would be able to notice them, and even then, experts do not always agree on what they notice. 

Let's say in my life I only see white swans. Maybe I write an essay, concluding that all swans are white. And a "peer" says, "Wait a minute, I've seen black swans. "I would have to refine my knowledge. 

The peer plays a key role evaluating observations with the overall goal of advancing knowledge. For example, if the above story were reversed, and peer reviewers who all believed that all swans were white came across the first study observing a black swan, the study would receive a lot of attention. 

So why was a first-year graduate student getting to stand in for an expert? Why would my review count the same as an expert's review? One answer: The process relies almost entirely on unpaid labor. 

Despite the fact that peers are professionals, peer review is not a profession. As a result, the same over-worked scholars often receive masses of the peer review requests. Besides the labor inequity, a small pool of experts can lead to a narrowed process of what is publishable or what counts as knowledge, directly threatening diversity of perspectives and scholars. Without a large enough reviewer pool, the process can easily fall victim to biases, arising from a small community recognizing each other's work and compromising conflicts of interest. 

Despite these challenges. I still tell my students that peer review offers the best method for evaluating studies aird advancing knowledge. As a process, peer review theoretically works. The question is whether the issues with peer review can be addressed by professionalizing the field.