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 that 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.”

    Motherhood may make women smarter and may help prevent dementia (痴呆) in old age by bathing the brain in protective hormones (荷尔蒙) , U.S. researchers reported on Thursday.

    Tests on rats show that those who raise two or more litters of pups do considerably better in tests of memory and skills than rats who have no offsprings, and their brains show changes that suggest they may be protected against diseases such as Alzheimer's (早老痴呆症). University of Richmond psychology professor Craig Kinsley believes his findings will translate into humans.

“Our research shows that the hormones of pregnancy are protecting the brain, including estrogen(雌激素), which we know has many neuroprotective (保护神经的) effects,” Kinsley said.

    “It's rat data but humans are mammals just like these animals are mammals,” he added in a telephone interview. “They go through pregnancy and hormonal changes.”

    Kinsley said he hoped public health officials and researchers will look to see if having had children protects a woman from Alzheimer's and other forms of age-related brain decline.

    “When people think about pregnancy, they think about what happens to babies and the mother from the neck down,” said Kinsley, who presented his findings to the annual meeting of the Society of Neuroscience in Orlando, Florida.

    “They do not realize that hormones are washing on the brain. If you look at female animals who have never gone through pregnancy, they act differently toward young. But if she goes through pregnancy, she will sacrifice her life for her infant—that is a great change in her behavior that showed in genetic alterations to the brain.”

    When you think back to the blackboard from your school days, what color is it? Chances are that it's green. So what's up with the name? Originally, blackboards were really black. Before wall-sized blackboards existed, late 18th-century students used their own mini boards made of slate (石板) or painted wood, according to Concordia University, Those first boards were, in fact, black, and they paved the way for the larger ones.

    In 1800 when a Scottish headmaster named James Pillans wanted his students to draw maps, the students couldn't draw the maps their teacher wanted on their tiny boards, so Pillans put several slates together to create a large board. Problem solved! From there, the idea spread quickly as teachers could finally show a concept to the whole class at one time. By 1815, the massive writing spaces were common enough to earn their own name: blackboard.

    The color change came in the 1960s when companies sold, steel plates, coated with green enamel (漆) instead of the traditional dark slate. The new material was lighter and less fragile than the first blackboards, so they were cheaper to ship and more likely to survive the journey. Teachers weren't complaining either. After all, the new "greenboards" made the chalk powder easier to erase. Plus, the enamel left less of a glare and the color was nicer to look at. At that point, people started using the word "chalkboard "as a more accurate descriptor, but "blackboard" still stuck around.

    Good health is the most valuable thing a person can have, but one cannot take good health for granted. It is important to remember that the body needs proper care in order to be healthy. There are three things that a person can do to help stay in good shape: eat right food, get enough sleep, and exercise regularly.

    Proper nutrition (营养) is important for good health. Your body cannot work well unless it receives the proper kind of "fuel"(燃料).Don't eat too much food with lots of sugar and fat. Eat plenty of foods high in protein (蛋白质) ,like meat, fish, eggs and nuts. Vegetables and fruits are very important because they provide necessary vitamins (维他命) and minerals. However, don't overeat. It is not helpful to be overweight.

    Getting the proper amount of sleep is also important. If you don't get enough sleep, you feel tired and easily get angry. You have no energy. Over a long period of time a little amount of sleep may even result in a change of personality (人的个性). Be sure to allow yourself from seven to nine hours of sleep each night. If you do, your body will feel strong and refreshed, and your mind will be sharp.

    Finally, get plenty of exercise. Exercise firms the body, strengthens the muscles, and prevents you from gaining weight. It also improves your heart and lungs. If you follow a regular exercise program, you will probably increase your life-span (寿命). Any kind of exercise is good. Most sports are excellent for keeping the body in good shapes: basketball, swimming, bicycling, running and so on are good examples. Sports are not only good for your body, but they are enjoyable and interesting, too.

    If everybody, were to eat the right foods, get plenty of sleep and exercise regularly, the world would be a happier and healthier place. We would all live to be much older and wiser.

Last year, the Bureau of Labor Statistics reported that 55 million people in the U. S. are "gig workers" which is more than 35 percent of the U. S. workforce. That number is projected to jump to 43 percent by 2020.

People are drawn to gig work（零工）because it brings in a little extra income without a major time commitment. And recent technologies like Skype, Slack, and Dropbox have made the gig life a reality, giving you maximum freedom, an ideal work-life balance, and the chance to pursue your passions.

If you're thinking of joining the gig economy, it's never been easier. One of the great things about the gig economy is that you don't have a boss breathing down your neck. As a freelancer, you no longer have to cater to a company culture or work schedule that might cause physical or emotional stress. Instead, you get to choose the type of work you do and who you work with. But this degree of freedom requires a corresponding amount of discipline. With no boss to make sure you're on task, it's all on you.

A lot of gig workers start their careers by hopping on a project because the employer is desperate and in need of help. On the employer's end, it's tough to take on people for higher management positions when the pool of talent is full of gig workers who haven't been given an opportunity to improve their skills. Businesses have to evolve to learn how to account for an influx (涌入) of temporary workers. It is harder for gig workers to become skilled and get promoted.

The workforce is becoming more advanced and educated by the day. You have to keep learning and keep up with industry trends to maintain a competitive edge. This is true even for people in traditional office settings, but it's critical if you're your own boss.

Have you ever heard of invisible ink? You may have seen it in movies. When light is shone on the paper which invisible ink is written on, you can read it!

As magical as this seems, the change in color is due to science. The ink is absorbing higher energy light and giving lower energy light. This reaction is an example of fluorescence (荧光) .

Light is a very broad term that describes a range of electromagnetic rays, including gamma rays, infrared light (红外光) and ultraviolet light. One part of the electromagnetic visible light is the colors that we can see with the human eye. These rays travel in curvy lines and each type of the ray is characterized by a different wave pattern. For example, Gamma rays have a shorter wavelength than infrared light. Shorter wavelength is connected with higher energy, so gamma rays also have more energy than infrared light.

Corals (珊瑚) are animals that live underwater. And the corals in the Red Sea exhibit fluorescence. Why is this happening? Scientists have shown that fluorescent objects absorb higher energy light and release lower energy light. Since the corals of the Red Sea are deep in the water where there is very little visible light, scientists theorize that these corals absorb ultraviolet light and produce visible light. They have special photo proteins, which enable them to change invisible light to visible light.

Fluorescence is not just used to create pretty colors. Corals have developed photo proteins for a biological reason. The visible light is used by algae (海藻) , which are eaten by the coral, to make food through photosynthesis (光合作用). The visual character of these photo proteins could also be used for biomedical research. They can highlight cells and cell structures under a microscope.

Isn't it amazing that a simple organism that we don't think very much of is not only grand but could also have so many potential uses in medical research!