"Over the years the unthinkable hasbecome thinkable and today we sense we are close to being able to alter humanheredity œ#)." These were the words of David Baltimore of the CaliforniaInstitute of Technology, on December 1st, when he opened a three-day meeting inWashington to discuss the morality and use of human gene editing. Dr Baltimoreis an old hand at these sorts of discussions, for he was also a participant inthe Asilomar conference, in 1975, which brought scientists together to discussa safe way of using the then-new tcchnology of recombinant DNA, and whoserecommendations influenced a generation of biotechnology researchers.

Four decades on, the need for a similarsort of chin-wag has arisen. The InternationalSummit on Human Gene Editing has been held by the national scientific academiesof three countries — America, Britain and China. They are particularlyconcerned about whether gene editing should be used to make heritable changesto the human germ line, something Dr Baltimore described as a deep andtroubling question. Like those of Asilomar, the conclusions of this meetingwill not be binding. But the hope is that, again like Asilomar, a mixture ofcommon sense and peer pressure will create a world in which scientists aretrusted to regulate themselves, rather than having politicians and civilservants do it for them. The meeting is being held against a backdrop of rapidscientific advance, Since 2012 research into a new, easy-to-use editing tool calledCRISPR-Cas9 has blossomed. This technique involves a piece of RNA (a chemicalmessenger, which can be used to recognise a target section of DNA) and anenzyme (酶)called a nuclease that can snip unwanted genes out and paste new ones in.

Public interest was aroused in April,when Chinese scientists announced they had edited genes in non-viable ( 无活力的) humanembryos, and again in November when British researchers said they hadsuccessfully treated a one-year-old girl who had leukaemia ( 白血病),using gene-edited T-cells. T-cells are part of the immune system that attack,among other things, tumour cells. The researchers altered T-cells from ahealthy donor to encourage them to recognise and kill the patient's cancer, tomake them immune to her leukaemia drug, and to ensure they did not attack herhealthy cells.

In another recent development, a firmcalled Edit as Medicine, which is based in Cambridge, Massachusetts, has saidit hopes, in 2017, to start human clinical trials of CRISPR-Cas9 as a treatmentfor a rare genetic form of blindness known as Leber congenital amaurosis (伯氏先天性黑蒙).Though other companies are already testing gene-editing therapies, these employolder, clunkier forms of the technology that seem likely to have lesscommercial potential. Moreover, researchers at the Broad Institute, also inCambridge, said this week that they had made changes to CRISPR-Cas9 whichgreatly reduce the rate of editing errors — one of the main obstacles to thetechnique's medical use.

On the subject of germ-line editing,Eric Lander, the Broad's head, told the meeting it would be useful only in rarecases and said it might be a good idea to "exercise caution? before makingpermanent changes to the gene pool. The need for caution is advice that mightalso be heeded by those pursuing work in animals other than people, and inplants — subjects not being covered by the summit.

    People with an impulsive personality refer to those who tend to do things without considering the possible dangers or problems first. According to a new study by researchers at the University of Georgia, such people may be more likely to have food addiction. The study found that people exhibiting impulsive behavior weren't necessarily overweight, but impulsiveness was related to a direct relationship with food, and therefore, less healthy weight.

    Food addiction has been compared to addictive drug use. Studies have linked the dopamine (多巴胺) release that occurs after tasting delicious food to the dopamine release that happens when people consume other addictive substances.

    Impulsive behavior involves several personality traits (特点). Two of these traits, known as negative urgency and lack of perseverance, were particularly associated with food addiction and high BMI (身体质量指数) during the study.

    Negative urgency is characterized by the tendency to behave impulsively when experiencing negative emotions. Some people might drink alcohol or take drugs. For others, it could mean eating to feel better. Lack of perseverance is when a person has a hard time finishing hard or boring tasks. People with a lack of perseverance might have difficulty attempting to change addictive eating behavior, which could also cause obesity.

    “Impulsiveness might be one reason why some people eat in an addictive way despite motivation to lose weight,” said Dr. Ashley Gearhardt, a clinical psychologist. He was involved in developing the Yale Food Addiction Scale in aid of those people. “We are theorizing that if food addiction is really a thing, then our measure, the Yale Food Addiction Scale, should be related to helping control impulsive action,” said Gearhardt.

    Clinical psychologist Dr. James MacKillop, whose lab was conducting the study, believes that therapies used to treat addictive drug behavior could help people who suffer from addictive eating habits.

    “Most of the programs for weight loss at this point focus on the most obvious things, which are clearly diet and exercise,” MacKillop said. “It seems that managing strong desires to eat would naturally fit in with the skills a person would need to eat healthily.”

    When asked about happiness, we usually think of something extraordinary, an absolute delight, which seems to get rarer as we get older.

    For kids, happiness has a magical quality: Their delight at winning a race or getting a new bike is unreserved (毫不掩饰的).

    In the teenage years, the concept of happiness changes. Suddenly it's conditional on such things as excitement, love and popularity. I can still recall the excitement of being invited to dance with the most attractive boy at the school party.

    In adulthood the things that bring deep joy－love, marriage, birth－also bring responsibility and the risk of loss. For adults, happiness is complicated (复杂的).

    My definition of happiness is “the capacity for enjoyment”. The more we can enjoy what we have, the happier we are. It's easy to overlook(忽视) the pleasure we get from the company of friends, the freedom to live where we please, and even good health.

    I experienced my little moments of pleasure yesterday. First I was overjoyed when I shut the last lunchbox and had the house to myself. Then I spent an uninterrupted morning writing, which I love. When the kids and my husband came home, I enjoyed their noise after the quiet of the day.

    Psychologists tell us that to be happy we need a mix of enjoyable leisure time and satisfying work. I don't think that my grandmother, who raised 14 children，had much of either. She did have a network of close friends and family, and maybe this is what satisfied her most.

    We, however, with so many choices and such pressure to succeed in every area, have turned happiness into one more thing we've got to have. We're so self-conscious about our “right” to it that it's making us miserable. So we chase it and equal it with wealth and success, without noticing that the people who have those things aren't necessarily happier.

    Happiness isn't about what happens to us－it's about how we see what happens to us. It's the skillful way of finding a positive for every negative. It's not wishing for what we don't have, but enjoying what we do possess.

    When you were at school, the last thing you probably wanted to do was spend your weekends going to work. There was homework to do, sport to play and fun to have. But our parents probably persuaded us to find a job to earn some money and get some life experience. When I was a teenager I had a paper round: delivering newspapers to people's homes. I then progressed to a Saturday job in a supermarket: stacking shelves and working at the checkout.

    Today in the UK you are allowed to work from the age of 13, and many children do take up part-time jobs. It's one of those things that are seen almost as a rite of passage (成人仪式). It's a taste of independence and sometimes a useful thing to put on your CV (简历). Teenagers agree that it teaches valuable lessons about working with adults and also about managing their money.

    Some research has shown that not taking up a Saturday or holiday job could be deleterious to a person later on. A 2015 study by the UK Commission on Employment and Skills found that not participating in part-time work at school age had been blamed by employer's organizations for young adults being ill-prepared for full-time employment, but despite this, recent statistics have shown that the number of schoolchildren in the UK with a part-time job has fallen by a fifth in the past five years.

    So, does this mean that British teenagers are now afraid of hard work? Probably not. Some experts feel that young people feel going out to work will affect their performance at school, and they are under more pressure now to study hard and get good exam results-and a good job in the long term. However, Geoff Barton, general secretary of the Association of School and College Leaders, told BBC News that “Properly regulated (控制的) part-time work is a good way of helping young people learn skills that they will need in their working lives." In reality, it's all about getting the right balance between doing part-time work and having enough time to study and rest.

    Listed here are four of the thousands of impressive museums around the world.

    The Guggenheim Museum Bilbao in Bilbao, Spain

    Built in 1997, the Guggenheim Museum Bilbao is one of the newest in the world. It has transformed the industrial city of Bilbao into a travelers' desired destination. The beautiful architecture of the museum has provided a dramatic background for movies and commercials.

    The Louvre in Paris, France

    Probably the most famous Louvre also holds the most famous painting in the world, the "Mona Lisa" by Leonardo da Vinci. Crowds can be found any day surrounding the small, but mysterious painting of the smiling woman. But, the Louvre is much more than a home to the "Mona Lisa". The Louvre is visited by more people each year than any other museum in the world.

    The Barnes Foundation in Philadelphia, America

    Just opened in its new downtown location in 2012, the Barnes Foundation is "unique" in that it is a completely reproduced display from one man's private collection. Dr. Albert C. Barnes started collecting art in the early 20th century and collected, among others, the largest number of original Renoir paintings in the world.

    The Uffizi Gallery in Florence, Italy

    Walking on the marbled floors feels like stepping back in time. The building itself is a beautiful palace—like structure with frescoes(湿壁画) decorating the ceilings and walls. Viewers are bowled over(印象深刻) by the works by Botticelli, such as "The Birth of Venus". Classic artworks from nearly 1, 000 years ago describe religious events of the time.

Harvard Pre-College Program

    Our summer program for high school students is designed to pave the way for a successful college experience.

    HERE YOU CAN:

    Learn without limits

    Pursue your interests in courses focusing on physics, law, writing, philosophy, and a dozen other subjects.

    Live at Harvard

    You will live in a historic undergraduate house near Harvard Square.

    Your plan covers three meals a day, seven days a week.

    Have fun outside the classroom

    You might enjoy a Cirque du Sileil performance, a Red Sox game at Fenway Park, or a trip to the Museum of Science.

    ELIGIBILITY (申请资格)

    Students are academically motivated and will graduate in 2020 or 2021.

    TO APPLY

    Complete an online application and provide the following materials: the $50 nonrefundable application fee; transcripts (成绩单) with fall 2018 grades; signed rules and regulations.

    INTERNATIONAL STUDENTS

    Participants should apply for the B-2 tourist visa. If English is not your native language, submit scores from the TOEFLor IELTS language proficiency exam.

    APPLICATION TIPS

    No fee is required to start your application. You will be asked to pay the application fee only upon submitting the application.

    The scores of successful applicants are typically above 103 on the TOEFL with 25 on the written section or at least 7.5 on the IELTS with 7 on the written section.

    Use a desktop or laptop. You will be asked to write short essays as part of your application. This may be challenging to do on a mobile phone.

    You will receive an email informing you of the application status approximately three weeks after you have completed your application.