How many times do you check your Facebook page in a day to see whether your latest post has got another “like” or “thumbs(拇指) up”?

    Although you might be embarrassed to admit how many times you do this, don't worry—psychological findings have shown it's completely normal. In fact, the pleasure we derive from receiving a “like” is equal to that of eating chocolate or winning money, and we can't help wanting more. According to the findings, which observed 32 teens aged between 13 and 18, the feedback circuit (反馈回路) in the teens' brains is particularly sensitive, and the “social” and “visual” parts of their brains were active when they received “likes” on the social network. The research also showed that though the thumbs up might come from complete strangers, the good they derive from them worked all the same.

    So, does it mean we should try our best to win as many thumbs up as possible? Not necessarily so if we know the reasons behind our desire for attention. In “why do people long for attention” by M. Farouk Radwan, he explained several cases in which people naturally longed for attention. Radwan said people who were an only child, who were used to being the center of attention in their house, may try to copy these conditions. Feeling “overlooked and unappreciated” might also lead you to long for attention. Other times, the state of being jealous, or wanting to cover your mistakes may also contribute to such longings.

    In fact, too much desire for attention can create anxiety, and in turn ruin your happiness even when you get it. So what can we do about it? The answer is quite simple. “If people could adopt goals not focused on their own self-esteem（自尊）but on something larger than their self, such as what they can create or contribute to others, they would be less sensitive to some of the negative effects of pursuing self-esteem,” wrote psychology professor Jennifer Crocker.

    So perhaps the answer to our addiction to “likes” is simply to focus on something larger than ourselves—a hard, but a worthy one.

    Recently, the Oxford English Dictionary, or OED, added about 1,000 words and new definitions to its website. The changes are to help users understand a mix of terms, some dating back many centuries. The additions include words such as "brencheese", "deathshildy" and "hip-pop".

    The new entries are part of the company's update to oed.com, its searchable online dictionary for paid members. The OED makes changes to the website four times each year. But the latest print version has been in process since the year 2000, and may not be ready for 10 more years. That information comes from Katherine Connor Martin, who heads the company's dictionary operations in the United States.

    Usually, the OED watches usage of a word for at least 10 years before deciding whether to add a new entry, new definition or word related to an existing entry, she said. This general rule, however, is sometimes not followed. That is what happened with "tweet", a word that the OED added far before the 10-year mark. Other times, the company adds words that are very old, but were not included in the dictionary in the past.

    “It's funny because we talk about new words, but many of the words we add are already obsolete. It's just that they were never in the dictionary before," Martin told the Associated Press.

    That is the reality, she said, of a historical dictionary trying to put more than 1,000 years of English into books that already have over 855,000 entries. So, you get "brencheese", a rarely used term for when bread and cheese are eaten together. The word dates back to the year 1665. The word "deathshildy" is from Old English. It means someone who is guilty of a serious crime and condemned to death.

    The website defines the term "hip-pop" for music that combines parts of hip-hop and popular music. The OED discovered the term “hip-hip pop” was used in a 1985 story from a Pennsylvania newspaper. It noted that the term "hip-pop" appeared in a 1991 U. S. newspaper report about the rap artist M.C. Hammer.

    The website has added several other terms related to modern culture. They include three popular terms: "binge-watching", "spoiler alert" and "microaggression".

    Here are a few other new entries if you long to read on.

    In an online class, developing healthy patterns of communication with professors is very important. {#blank#}1{#/blank#} While I have only listed two of each, there are obviously many other situations that can arise. Students should be able to extend the logic（逻辑）of each to their particular circumstance.

    Do's

    •{#blank#}2{#/blank#} Questions about subject content are generally welcomed. Before asking questions about the course design, read the syllabus（教学大纲）and learning management system information to be sure the answer isn't hiding in plain sight.

    •Participate in discussion forums（论坛）， blogs and other open-ended forums for dialogue. {#blank#}3{#/blank#}Be sure to stay on topic and not offer irrelevant information. Make a point， and make it safe for others to do the same.

    Don'ts

    •Don't share personal information or stories. Professors are not trained nurses, financial aid experts or your best friends. If you are in need of a deadline extension, simply explain the situation to the professor. {#blank#}4{#/blank#}

    •Don't openly express annoyance at a professor or class. {#blank#}5{#/blank#} When a student attacks a professor on the social media，the language used actually says more about the student. If there is truly a concern about a professor's professionalism or ability, be sure to use online course evaluations to calmly offer your comments.

A. If more information is needed, they will ask.

B. Below are some common do's and don'ts for online learners.

C. That's what they are for.

D. Ask questions, but make sure they are good, thoughtful questions.

E. Everyone has taken a not-so-great class at one time or another.

F. Turn to an online instructor for help.

G. Remember that online professors get a lot of emails.

    Hacking isn't just for computers and smart phones. According to a study, scientists have found a way to hack a plant's genes in order to make it use sunlight more quickly. Someday, the results could increase the number of food produced around the world.

    Scientists used tobacco plants in the study because it is easy to change the plants^' genes. Hacked plants are larger than normal plants.

    Photosynthesis is the word used to describe how plants use sunlight, water and carbon dioxide to make their own food. Scientists say this is a very slow process. Plants use less than 1 percent of the energy. But by hacking a plant's genes, the scientists were able to increase the amount of leaf growth on plants between 14 and 20 percent. Scientists hacked the plant's protective system. Normally, this system starts when a plant gets too much sunlight. When the plant senses the light, it creates more leaves. When the plant is in shade, the protective system is turned off. But the process is slow.

    The new study sped up the process by changing the plant's genes, the protective system turned on and off more quickly than normal. As a result, leaf growth on the plants scientists used in the study increased. Leaf growth on two plants increased by 20 percent, while leaf growth on a third plant increased by 14 percent. Scientists conducted the study on tobacco plants. But they think the genetic changes would produce the same results in corn and rice.

    Agriculture professor Tala Awanda said the study makes sense, but cautioned the yield（产量）might not be quite so high for conventional food crops. Still, she added in an email, "this study remains a breakthrough,"

    Why is it that many people who have suffered a major shock, such as divorce or death of a family member, seem to be weaker against a variety of major and minor illness? One common idea among psychologists has been that people could deal with suffering more effectively if they were able to understand and accept it. Indeed, many experts stress the value of expressing thoughts and feelings connected with upsetting events.

    Recently, a team of medical researchers studied the links between describing psychologically painful events and long-term health. In one experiment healthy college students were asked to write about either personally disturbing experiences or ordinary topics over a period of four days. In the months afterwards, students who had chosen to show their inner thoughts and feelings in their writing visited the health center for illness much less often than those who had written about everyday topics.

    In an experiment that followed, another group of healthy students were given the four-day writing exercises. Some chose to write about highly personal and upsetting experiences (including loneliness, problems with family and friends, and health). When questioned immediately afterwards, they said that they did not feel any better. However, their blood samples(样本) taken before and after the experiment showed evidence of an improved resistance to illness. The white cells that fight off bacteria and viruses had increased their reaction and sensitivity to these "invaders". This trend continued over the following six weeks, when another blood sample was taken. Individuals who showed the best results were those who wrote about topics that they had actively kept from telling others about.

    The researchers suggested that failure to face up to painful experience can be a form of stress itself, and can increase the possibility of illness. It follows, then, that actively dealing with a major shock makes possible its understanding and acceptance. The answer is not to suffer in silence. It may not always be possible to talk about personal problems, but writing them down will help the body to fight disease in the long run.

Grizzly bears,which may grow to about 2.5 m long and weigh over 400 kg,occupy a conflicted corner of the American psyche—we revere(敬畏) them even as they give us frightening dreams.Ask the tourists from around the world that flood into Yellowstone National Park what they most hope to see,and their answer is often the same:a grizzly bear.

"Grizzly bears are re-occupying large areas of their former range,"says bear biologist Chris Servheen.As grizzly bears expand their range into places where they haven't been seen in a century or more,they're increasingly being sighted by humans.

The western half of the U.S.was full of grizzlies when Europeans came,with a rough number of 50,000 or more living alongside Native Americans.By the early 1970s,after centuries of cruel and continuous hunting by settlers,600 to 800 grizzlies remained on a mere 2 percent of their former range in the Northern Rockies.In 1975,grizzlies were listed under the Endangered Species Act.

Today,there are about 2,000 or more grizzly bears in the U.S.Their recovery has been so successful that the U.S.Fish and Wildlife Service has twice attempted to de-list grizzlies,which would loosen legal protections and allow them to be hunted.Both efforts were overturned due to lawsuits from conservation groups.For now,grizzlies remain listed.

Obviously,if precautions(预防) aren't taken,grizzlies can become troublesome,sometimes killing farm animals or walking through yards in search of food.If people remove food and attractants from their yards and campsites,grizzlies will typically pass by without trouble.Putting electric fencing around chicken houses and other farm animal quarters is also highly effective at getting grizzlies away."Our hope is to have a clean,attractant-free place where bears can pass through without learning bad habits,"says James Jonkel,longtime biologist who manages bears in and around Missoula.