People born in winter are more likely to suffer mental health disorders, according to a recent study carried out by researchers at Vanderbilt University in Tennessee.

    Researchers raised baby mice from birth to weaning (断奶) in either “summer” light cycles of 16 hours of light and 8 hours of dark or “winter” cycles of 8 hours of light and 16 hours of dark. A third group experienced 12 hours of light and 12 hours of dark a day.

    Then half the winter mice stayed in a winter cycle, while half switched to a summer schedule. The summer mice were similarly split. The mice raised in equal periods of light and dark were split into three groups, one of which stayed on the 12­hour schedule, one of which joined the winter group, and one of which joined the summer group.

    After 28 days, it turns out the summer­born mice behaved the same whether they stayed on the summer cycle or switched to winter. But among the winter­born mice, those stayed in winter kept their previous schedule, while those that switched to summer stayed active for an extra hour and a half, which indicates that mice born and weaned in a winter light cycle showed dramatic disruptions（破坏） in their biological clocks.

    The finding is the first of its kind in mammals, and it could explain why people born in winter are at higher risk for mental health disorders.

    “We know that the biological clock regulates(管理) mood in humans,” said study researcher McMahon. “If the mechanism (机制) similar to the one that we found in mice operates in humans, then it could not only have an effect on a number of behavioral disorders, but also have a more general effect on personality.”

    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.

    Last Sunday, my whole family went to the amusement park near our hometown. As we planned the day before, on my brother's 13th birthday. David was two years older than I.

The weather was perfect and everyone was happy. The park was not too crowded. "Fioda," said my brother, "do you want to go on that ride with me?" "Of course," I said. The ride was brand new. I saw commercials(广告) for this huge roller coaster(过山车） on television. I was so excited to ride it. As we got in line, we talked excitedly about what we might experience. We decided that we would both try to keep our hands in the air the whole time. We believed that would make it even more enjoyable. I was so busy talking to my brother that I missed the most important sign—-Empty your pockets before going on the ride. Something bad happened!

    The ride started. It was a really fast roller! Before I knew it, we were upside down. I felt my phone slipping（滑落） from my pocket. My hands were in the air, just as we had promised, and I didn't catch my phone in time. It hit me on the head, fell down to the ground and broke. My parents said I wouldn't have a new phone until I had enough money to pay for it. I need to be more careful. Next time, I'll pay better attention the warning signs as we wait in line for the ride.

    There has long been a notion （观念） that money buys happiness. However, although "we really, really tried that for a couple of generations, it didn't work," said Francine Jay, author of The Joy of Less, A Minimalist Living Guide: How to Declutter, Organize, and Simplify Your Life.

    Thanks to a travel inspired revelation （启发）, Jay has been happily living a simpler life for 12 years. "I always packed as lightly as possible, and found it exciting to get by with just a small carry on bag," she told CNN. "I thought if it feels this great to travel lightly, how amazing would it be to live this way？ I wanted to have that same feeling of freedom in my everyday life."

Jay decided to get rid of all her excess （额外的） possessions and live with just the essentials （必需品）. "I wanted to spend my time and energy on experiences, rather than things."

    Jay is a follower of a movement called "minimalism （极简主义）". Growing numbers of people have been attracted to this lifestyle all over the world. They share the same feeling of disappointment with modern life and a desire to live more simply. Minimalists are typically progressive and concerned about the environment, Leah Watkins, a lead researcher at Ota go University in New Zealand, told Stuff magazine in March.

    But many simply experienced unhappiness caused by owning too many possessions. Depression with the materialism of our world isn't new. English romantic poet William Wordsworth summed up how dispiriting （令人消沉的） this was back in 1802, at the beginning of the industrial age, when he wrote: "Getting and spending, we lay waste our powers". His preference was to go back to nature. Closer to our own times, the hippies （嬉皮士） of the 1960s also sought to "drop out" of modern life.

    And for many minimalists, their key is to unload. Without objects, they "believe people are forced more and more into the present moment and that's where life happens," wrote Stuff.

But does simplicity ever feel like a sacrifice （牺牲）？

    "It's eliminating the excess﹣unused items, unnecessary purchases﹣from your life. Well, I may have fewer possessions, but I have more space …Minimalism is making room for what matters most," said Jay.

    And "the real questions", according to Duane Elgin, US social scientist, are "what do you care about？" and "What do you value?"

    He told CNN: "It's important for people to realize minimalism isn't simply the amount of stuff we consume. It's about our families, our work, our connection with the larger world, our spiritual dimension. It's about how we touch the whole world. It's a way of life."

    For teenagers, it's great fun to explore new places and it feels like an adventure, even when you know you're not the first to have been there. But to make sure not to get lost or waste time going round in circles, the following tips may be helpful.

    Do the map reading if you're being driven somewhere. It'll be easier if you keep the map following the direction you are traveling in. Keep looking ahead so that you can give the driver lots of warning before having to make a turn, or you'll have to move to the back seat.

    Get a group of friends together and go exploring. You'll need a good map, a compass , a raincoat, a cell phone to call for help in case you get lost, and a bit of spare cash for emergencies .Tell someone where you're going before you set out and let them know what time you expect to be back. The purpose of the activity is in not getting lost, not in seeing how fast you can go, so always stick together, waiting for slower friends to catch up.

    See if your school or a club organizes orienteering（越野识途比赛）activities, in which you need a map and a compass to find your way. This can be done as a sport, with teams trying to find the way from A to B(and B to C, etc. ) in the fastest time, or simply as a spare-time activity. It enables you to be familiar with the use of maps and compass and gain some special skills. In some way, it's not only good fun, but also a great way to keep fit.

    The world's insects are hurtling down the path to extinction, threatening a "catastrophic collapse of nature's ecosystems", according to the first global scientific review. More than 40% of insect species are declining and a third are endangered, the analysis found. The rate of extinction is eight times faster than that of mammals, birds and reptiles.

    "It should be of huge concern to all of us, for insects are at the heart of every food web,  they pollinate the large majority of plant species, keep the soil healthy, recycle nutrients, control pests, and much more. Love them or loathe them, we humans cannot survive without insects," said Prof Dave Goulson at the University of Sussex in the UK.

    The analysis, published in the journal Biological Conservation, says intensive agriculture is the main driver of the declines, particularly the heavy use of pesticides. Urbanization and climate change are also significant factors.

    One of the biggest impacts of insect loss is on the many birds, reptiles, amphibians and fish that eat insects. A small number of adaptable species are increasing in number, but not nearly enough to outweigh the big losses.

    Matt Shardlow, at the conservation charity Buglife, said: "It is gravely sobering to see this collation of evidence that demonstrates the pitiful state of the world's insect populations. It is increasingly obvious that the planet's ecology is breaking and there is a need for an intense and global effort to stop and reverse these dreadful trends."