Donald Trump has been known to do it in the middle of the night. Kim Kardashian has done it more than 22,000 times. Many people don't understand why you would want to do it at all.

    We're talking about tweeting and, unlike posting your entire life on Facebook, this social media activity demands a particular set of skills.

    Why use Twitter? It's a way to have a one-on-one virtual connection with your heroes and anybody who interests you. Likewise, you can share your life and views with an almost limitless number of people. And it all has to be done within the limit of 140 characters of text – plus photos, videos and links – which really helps you focus your mind.

    Katy Perry has the most Twitter followers, with 95.6 million of the micro-blogging site's 317 million monthly active users. Justin Bieber isn't far behind with 91.5 million, followed by Barack Obama and Taylor Swift with around 83 million each. The heaviest hitters of Twitter are pop stars, heroes of sport and other celebrities. But you don't need to be famous to create a buzz with the right tweets at the right time.

    In fact, Katy Perry is a great example of how to do it well. She has a bubbly tweeting style that mashes up chat about her tours and her music, insights into her emotional roller coaster over the US election, and playful descriptions about her daily life. "Done with my Christmas shopping", she tweeted, and posted a link to her Instagram page that featured crazy gadgets like a "pet emergency jacket" and a "chocolate donut camera".

    To get started on Twitter, pick a simple, memorable user name like @KatyPerry, post a short profile and choose a photo. Some tips: post your own photo (not a photo of your dog, it's not Facebook) and don't be an "egg person" – referring to the absent egg-shaped image when a user hasn't posted their own picture. In that case, Twitter won't get you any followers or respect.

    Then, it's time to start tweeting by sending your updates ("what's happening?") and following people. Building up an army of followers can take time. Generally, the more people you follow and the more you tweet, the more followers you'll get. To become a Twitter star, you need to carve out a reputation for posting original, eye-catching tweets on trending topics – and maximise your visibility by mastering the use of hashtags.

    Twitter Analytics will show you how your tweets are performing and who is following you – right down to their age category, country, income bracket, gender and interests. If your popularity is flagging and your Twitter ego is keeping you awake at night, you can turn to the business of buying thousands of "followers" from online sites. But do be ware – there may be a lot of fake profiles in there and, at the end of the day, it'll feel like paying a crowd of people you don't know to come to your birthday party.

    Happy tweeting!

    Yesterday night, over a dinner with my elder brother's family, a topic of happiness came up. My wife, Marla, a psychologist, was sharing Csikszentmihalyi's concept of “flow” with us. Marla explained that according to the research on flow, people are happiest when they are absorbed in a task that is just challenging enough for them to experience a sense of mastery(熟练).

    A few moments later my brother, Yuri, offered the following opinion: “The first and only, necessary and sufficient factor for happiness is to stop associating happiness with pleasure. The two — happiness and pleasure — have nothing to do with each other.” This morning, with my cup of coffee, I searched through a pile of books on my bedside table and—at the bottom—found a book by Bertrand Russell, I started reading but didn't finish. In it, I found the following thought:

    “The human animal, like others, is adapted to a certain amount of struggle for life, and when by means of great wealth homo sapiens can gratify all his whims (突发奇想) without effort, the mere absence of effort from his life removes an essential ingredient of happiness.”

    The conversation came full circle: people are happiest when they are in a state of flow (Csikszentmihalyi's language )…which is the effortful devotion in a moment…which has nothing to do with pleasure.

    Indeed, as Yuri insisted : happiness–as–pleasure is a myth; the association between happiness and pleasure is nothing but a semantic(语义的) habit; psychologically, the two—happiness and pleasure—are arguably different; and breaking up this association between pleasure and happiness might, in fact, be a powerfully first step in pursuit of happiness.

    As I look back on that exchange, I recall that there was an effort, a struggle to find a common understanding about this seemingly difficult idea—a struggle that made me happy.

    Drug companies have spent billions of dollars searching for therapies to reverse or significantly slow Alzheimer's disease, but in vain. Some researchers argue that the best way to make progress is to create better animal models for research, and several teams are now developing mice that more closely imitate how the disease destroys people's brains.

    The US National Institutes of Health (NIH), the UK Dementia Research Institute and Jackson Laboratory (JAX) - one of the world's biggest suppliers of lab mice - are among the groups trying to genetically design more suitable mice. Scientists are also exploring the complex web of mutations(突变) that influences neurological (神经学的) decline in mice and people.

    "We appreciate that the models we had were insufficient. I think it's sort of at a critical moment right now." says Bruce Lamb, a neuro-scientist at Indiana University ~ho directs the NIH-funded programme.

    Alzheimer's is marked by cognitive impairment(认知损伤) and the build-up of amyloid-protein plaques (淀粉样蛋白块) in the brains of people, but the disease does not occur naturally in mice. Scientists get around this by studying mice that have been genetically modified to produce high levels of human amyloid protein. These mice develop plaques in their brains, but they still do not display the memory problems seen in people.

    Many experimental drugs that have successfully removed plaques from mouse brains have not lessened the symptoms of Alzheimer's disease in people. One focused stumble came last month, when three companies reported that their Alzheimer's drugs had failed in large, late-stage clinical trials. Although the drugs successfully blocked the accumulation of amyloid protein in mice, they seemed to worsen cognitive decline and brain shrinkage in people.

    The drive for better mouse models comes as genomics studies are linking the most common form of Alzheimer's to dozens of different genes. This diversity suggests that each case of the disease is caused by a different combination of genetic and environmental factors. "There is no single Alzheimer's disease," says Gareth Howell, a neuro-scientist at Jackson Laboratory (JAX) in Bar Harbor, Maine.

    Howell argues that scientists' reliance on lab mice with only a few genetically engineered mutations might have limited research. His own work suggests that in mice, just as in people, genetic diversity plays a part in determining how Alzheimer's develops.

    Whenever we see a button, we are eager to press it because we know something will happen. This is true in most cases, for example on a doorbell and on the “on/off” button on the TV. But some buttons are actually fake, like the “close” button on a lift.

    Many people are in the habit of pressing the “close” button because they don't have the patience to wait for the lift doors to shut. But lifts, “close” buttons are a complete scam, at least in the US—the doors will not close any faster no matter how hard you press.

    It started in the 1990s when the Americans with Disabilities Act was passed in the US, making sure that all lifts stayed open long enough so that people with disabilities could enter. Only US firefighters and repairmen can use the buttons to speed up the door-closing process if they have a code or special keys.

    But to normal lift riders, the buttons aren't completely useless. According to psychologists, fake buttons can actually make you feel better by offering you a sense of control.

    “Perceived (能够感知的) control is very important. It reduces stress and increases well-being,” Ellen J. Langer, a psychology professor, said, “Having a lack of control is associated with depression.”

    Experts have revealed that a lot of buttons that don't do anything exist in our lives for this same purpose. For example, many offices in the US have fake thermostats (温度调节器) because people tend to feel better when they think they can control the temperature in their workspace.

    But psychologists found it interesting that even when people are aware of these little “white lies”, they still continue to push fake buttons because as long as the doors eventually close, it is considered to be worth the effort.

    “That habit is here to stay,” John Kounios, a psychology professor, said, ''Even though I have real doubts about the traffic light buttons, I always press them. After all, I've got nothing else to do while waiting. So why not press the button in the hope that this one will work?”

    As you know, there are many fantastic parks in New York City.

    Central Park

    One of the most famous parks in the world, Central Park is a man-made wonder. Not only is it the first public park built in America, but it is also one of the most frequently visited parks, with over 25 million guests per year. Set in the middle of busy Manhattan, its grounds serve as a safe harbor, not only for athletes, and musicians but also for lots of migratory birds each year. One can spend an entire peaceful day wandering its grounds, gazing upon nearly 50 fountains, monuments, and sculptures or admiring its 36 bridges.

    Hudson River Park

    Hudson River Park is a waterside park on the Hudson River that extends from 59th Street south to Battery Park in the New York City district of Manhattan. Bicycle and pedestrian paths, including the Manhattan Waterfront Greenway, span the park north to south, opening up the waterfront for the public to relax. The park includes tennis and soccer fields, children's playground, dog run, and many other features.

    Washington Square Park

    Washington Square Park, located in the heart of Greenwich Village, is a very popular and often crowded place. People from all backgrounds gather to this large square dotted with trees.

    Central Park Zoo

    The Central Park Zoo is a small 6. 5-acre zoo located on Central Park in New York City. The zoo began in the 1860s, making it the first official zoo to open in New York. The zoo was improved in 1934, with the addition of many new buildings ranged in a quadrangle around the sea lion pool. Finally, the zoo was repaired in the mid-1980s and reopened in 1988, replacing the old-fashioned cages with naturalistic environments.

Humans aren't the only animals that move to music. Parrots have been known to do it. And now rats have been observed bopping their heads in time with the tunes of Mozart, Lady Gaga, Michael Jackson and others, according to a new paper from the University of Tokyo. What's more, the rats seems to respond to the same beats that get humans' feet tapping (轻跺). 

The researchers played a sonata by Mozart for lab rats at different variations of the original speed. Wireless sensors on the rats' bodies tracked their movements. Meanwhile, 20 human participants were involved and listened to the same music through headphones equipped with motion sensors. 

It was observed that the rats' head movements were the most obvious when the music played at its normal speed, which was around 132bpm (beats per minute). The same was true for human participants. The researchers then changed to some pop songs such as Lady Gaga's "Born This Way" and Michael Jackson's "Beat It". As with Mozart's, rats moved their heads along the rhythm of pop songs, similar to how people do, at about 120 to 140bpm. 

The study showed that both rats and humans moved their heads along to the beat in a similar rhythm. The level of head bopping from both humans and rats decreased as the music sped up. The study suggests that there is something similar about the way human and rat brains respond to rhythms, but rats do not match their motions to the beat like humans do. Humans can predict the timing of a beat and move predictably to it. 

Aniruddh Patel, a psychologist who studies brain response to music, says humans and parrots respond to beats with big, voluntary movements such as head shaking, dancing or foot tapping. Patel also stresses that this study does not show that rats have the same emotional associations with music as humans do. Yet he believes it could help reveal how humans and some other animals developed a sense of rhythm.