Do you believe that things are connected for no scientific reason at all? For example, do you avoid saying the word "four" to avoid bad luck? If so, you have a superstition (迷信). And you're not alone — all kinds of people have them.

For example, Portugal's soccer superstar Cristiano Ronaldo always steps onto the pitch (球场) with his right foot first, according to The Telegraph. And sports players are not alone in having superstitions. A visitor once asked the Nobel Prize winning scientist Niels Bohr whether he really believed that the horseshoe he'd hung at his country home was lucky. "Of course not," the Danish physicist said. "But I understand it's lucky whether you believe in it or not."

One recent study found that even scientists at MIT and other top US schools tended to look for a meaning in natural events, similar to the connection between stepping on the pitch and playing soccer well, according to The Atlantic. When the researchers gave the scientists little time to answer questions, they were twice as likely to agree with statements such as "Trees produce oxygen so that animals can breathe" as they were when they had more time to think about their reply.

It seems that fear can make people think differently in this way, too. In a British study, students imagined meeting a "witch" who said she would cast (施魔法) an evil spell(符咒) on them. About half said a scientist should not be worried about the spell. Yet each of them said that, personally, they wouldn't let the witch do it to them.

So why are so many of us superstitious? Well, it seems to be our way of dealing with the unknown. "Many people quite simply just want to believe," Brian Cronk, a professor of psychology at Missouri Western State University, said in a 2008 interview. "The human brain is always trying to work out why things happen, and when the reason is not clear, we tend to make up some pretty bizarre (古怪的) explanations."

    And these explanations aren't completely unhelpful. In fact, superstitions can sometimes work and bring real luck, according to psychologists at the University of Cologne in Germany in the May 2010 issue of the journal Psychological Science. They found that believing in something can improve performance on a task like an exam.

    So, what about you? What superstitions do you follow to keep you safe and successful?

    In recent decades, social isolation has been recognized as a major risk to our health and long life. It's twice as bad for you as being overweight and nearly as bad as smoking. The rising number of people who say they are affected, across a wide range of ages, is shocking. In reality, you can suffer the ill effects of loneliness even if you are not socially isolated.

Comedian Robin Williams made a striking observation in 2014: "I used to think the worst thing in life was to end up all alone. It's not. The worst thing in life is to end up with people who make you feel all alone." Tracking large groups over time indicates that perceived（感知的）social isolation carries its own risk for morbidity（发病率）and mortality.

    The perception of isolation—from others of being in the social aspect-is not only a cause of unhappiness, it also signals danger. Fish have evolved to swim to the middle of their group when predators（捕食者）approach, mice housed in social isolation show sleep disruptions and reduced slow-wave sleep and prairie voles（田鼠）isolated from their partners then placed in an open field explore their surroundings less and concentrate on avoiding predators.

    These behaviours reflect an increased emphasis on self-preservation in the social aspect. For instance, fish on the edge of a school are more likely to be attacked by predators because they are easier to isolate and prey upon. Such observations reflect a more general principle that perceived social isolation in social animals activates neural（神经系统的）, neuroendocrine（神经内分泌的）and behavioural responses that promote short-term self-preservation. However, these responses bring a cost for long-term health and well-being.

    The range of harmful neural and behavioural effects of perceived isolation documented in adults include increased anxiety, hostility and social withdrawal; fragmented sleep and daytime tiredness; increased vascular resistance and changed gene expression and immunity; decreased impulse control; increased negativity and depressive symptoms; and increased age-related cognitive decline.

    Sadly, to date, attempts to reduce loneliness have met with limited success. A series of randomized controlled trials showed that they had only a small effect. Among the four types of interventions（介入）examined, talking therapy that focused on inappropriate thought processes had the largest impact. Social skills training, social support and increased opportunities for social contact were much less effective.

    From July to October every year, about a quarter of the world's blue whales feed in the Pacific Ocean off the coast of California. But the whales currently face a major threat in their favorite feeding area. Ships carrying cargo （货物）sail in the same area at the same time. All too often, the whales' paths and the ships' travel lines overlap (重叠), and a ship will hit a whale.

    According to a new study, these ship strikes have become a serious threat to the overall population of the world's blue whales. Only about 10,000 of the creatures still exist worldwide. Blue whales are the largest known animals ever to live on Earth. Even so, if hit by a container ship, a blue whale will likely die from its injuries.

    In 2007 alone, large ships killed five blue whales in the waters off San Francisco and Los Angeles, California. The National Oceanic and Atmospheric Administration (NOAA) says that because there are so few whales already, losing three to five from the California whale population every year is a significant loss. "The estimated population of blue whales in this part of the Pacific is 2,500", says Sean Hastings, a NOAA analyst. "So every whale counts toward this species moving off the endangered-species list."

    Now, marine scientists must figure out how to protect the whales from the giant container ships. One very simple program is already under way in the Santa Barbara Channel, a waterway that separates mainland California from the nearby Channel Islands.

    The Channel Islands National Marine Sanctuary has asked large container ships passing through the area to voluntarily slow down. Sailing slower will allow the ships crew （船员）more time to change course before hitting a whale.

    Several of the world's largest shipping lines are set to participate in the new program. For every ship that passes through the Santa Barbara Channel at or below the reduced speed of 12 knots （海里/小时）, the company that owns the ship will be paid $2,500.

    Body language is a broad term for several forms of communication using body movements or gestures, instead of, or as a complement to, sounds, verbal language, or other forms of communication. In turn, it is one category of paralanguage, which describes all forms of human communication that are not language.

    Paralanguage including body language has been extensively studied in social psychology. In everyday speech and popular psychology, the term is most often applied to body language that is thought to be involuntary, but in fact the distinction between voluntary and involuntary body language is often blurred: a smile or a wave may be given either voluntarily or involuntarily, for example.

    Voluntary Body Language is less commonly discussed because it seems unproblematic. It refers to movement, gestures and poses intentionally made by the person: smiling, hands, imitating actions, and generally making movements with full or partial intention of making them and a realization of what they communicate.

    The relation of body language to animal communication has often been discussed. Human paralanguage may represent a continuation of forms of communication that our non-linguistic ancestors already used, or it may be that it has been changed by co-existing language. Some species of animals are especially skilled at detecting human body language, both voluntary and involuntary: this was the reason for trying to teach the chimpanzee Washoe American Sign Language rather than speech and perhaps the reason why the Washoe project was more successful than some previous efforts to teach apes how to dance.

    Body language is a product of both genetic and environmental influences. Blind children will smile and laugh even though they have never seen a smile. The ethnologist (文化人类学者) Iraneus Eibl-Eibesfeldt claimed that a number of basic elements of body language were universal across cultures and must therefore be fixed action patterns under instinctive (本能的) control. Some forms of human body language show continuities with communicative gestures of other apes, though often with changes in meaning. More refined gestures, which vary between cultures (for example the gestures to indicate "yes" and "no"), must obviously be learned or modified through learning, usually by unconscious observation of the environment.

    Whales, like all mammals(哺乳动物),need air, and come to the surface to breathe through a blowhole. A drone(无人机)that floats over the blowholes of humpback whales as they are making annual journey along Australia's east coast is being used by Australian scientists for collecting nasal mucus(鼻腔粘液)of whales.

    Vanessa Pirotta, a biologist at Macquarie University says that nasal mucus indicates the health of the whale. "It is the biological mixture that you see as a whale takes a breath as it surfaces from the water," she said. You can hear sounds of sharp breaths as a whale breathes because, after all, they are animals like you and I. So as they take a breath it is a lot of lung bacteria coming out from their lungs, which we can collect to provide a brief idea of whale health.

    Australian researchers have attached a special dish that is used in scientific tests to a drone which flies through the whale's nasal mist. As a whale comes to take a breath—you can actually see it coming to the surface on really good weather days —the drone then lowers, the dish is then opened, collecting nasal mucus for later research.

    The research could help to solve one of the secrets of another impressive creature of the deep —the Southern right whale. Its numbers have recovered on Australia's west coast since hunting became suppressed but its population on the eastern seaboard remains stubbornly low.

    In the past, studies into whale health had to rely on examining whales that were either killed or those whales that had been trapped on a beach. Drones allow scientists to collect nasal mucus from free-swimming whales to gather information in a safe way.

A short period of sleep taken during the day is known as a nap. Naps don't just have benefits for adults at work, though. They could also help pupils to make the most of their school day. Studies have shown that a 20 to 30-minute "beauty sleep" makes people more alert and focused. This improves people's ability to remember new information, which would help school children concentrate during lessons. Experts say that napping also improves brain functions, such as memory and the ability to complete difficult tasks.

The school day starts early, which means that pupils don't always get enough sleep because there's no chance to have a lie-in（睡懒觉. Adding naptime during the school day would help exhausted pupils to make up for any sleep they've lost from getting up so early.

There are long-term benefits to taking a short nap, too. According to a recent study from University College London, the brains of people who have regular naps are bigger than those who don't. People's brains naturally shrink (萎缩）when they grow old, and the results showed that little sleeps can help people's brains to age more slowly.

Although a nap can seem like a good idea, going to sleep for too long can actually make you feel worse. It's not very pleasant to wake up from a daytime nap feeling confused and sleepy. Napping during the day can also have a negative impact on how well you sleep at night. This can create a cycle of not being able to sleep well at night, leaving you feeling even more tired in the daytime. Sleep expert Dr Clete Kushida said, "It's generally recommended to maximize(最大化） sleep at night."

Another consideration is that there really isn't time in the school day for pupils to go to sleep. Some parents and teachers are concerned that it would cause children to miss too much lesson time. Pupils might take advantage of the system and use their need for a nap as an excuse to get out of lessons.

So, what do you think? Should school allow kids to have naps, or should you wait until the evening to catch up on your sleep?