Why do some people live to be older than others? You know the standard explanations: keeping a moderate diet, engaging in regular exercise, etc. But what effect does your personality have on your longevity?Do some kinds of personalities lead to longer lives?A new study in the Journal of the American Geriatrics Society looked at this question by examining the personality characteristics of 246 children of people who had lived to be at least 100.

    The study shows that those living the longest are more outgoing,more active and less neurotic (神经质的) than other people.Long-living women are also more likely to be sympathetic and cooperative than women with a normal life span.These findings are in agreement with what you would expect from the evolutionary theory: those who like to make friends and help others can gather enough resources to make it through tough times.

    Interestingly, however, other characteristics that you might consider advantageous had no impact on whether study participants were likely to live longer.Those who were more self-disciplined,for instance,were no more likely to live to be very old.Also,being open to new ideas had no relationship to long life,which might explain all those bad-tempered old people who are fixed in their ways.

    Whether you can successfully change your personality as an adult is the subject of a longstanding psychological debate.But the new paper suggests that if you want long life,you should strive to be as outgoing as possible.

    Unfortunately, another recent study shows that your mother's personality may also help determine your longevity.That study looked at nearly 28,000 Norwegian mothers and found that those moms who were more anxious, depressed and angry were more likely to feed their kids unhealthy diets.Patterns of childhood eating can be hard to break when we're adults,which may mean that kids of depressed moms end up dying younger.

    Personality isn't destiny(命运),and everyone knows that individuals can learn to change.But both studies show that long life isn't just a matter of your physical health but of your mental health.

    A team of engineers at Harvard University has been inspired by Nature to create the first robotic fly. The mechanical fly has become a platform for a series of new high-tech systems. Designed to do what a fly does naturally, the tiny machine is the size of a fat housefly. Its mini wings allow it to stay in the air and perform controlled flight tasks.

    “It's extremely important for us to think about this as a whole system and not just the sum of a bunch of individual components,” said Robert Wood, the Harvard engineering professor who has been working on the robotic fly project for over a decade. A few years ago, his team got the go-ahead to start piecing the components together. “The added difficulty with a project like this is that actually none of those components are off the shelf and so we have to develop them all on our own,” he said.

    They engineered a series of systems to start and drive the robotic fly. “The seemingly simple system which just moves the wings has a number of interdependencies on the individual components, each of which individually has to perform well, and then has to be matched well to everything it's connected to,” said Wood. The flight device was built into a set of power, computation, sensing and control systems. Wood says the success of the project proves that the flying robot with these tiny components can be built and manufactured.

    Wood says the design offers a new way to study flight mechanics and control at insect-scale. Yet, the power, sensing and computation technologies on board could have much broader applications. “You can start thinking about using them to answer open scientific questions, you know, to study biology in ways that would be difficult with the animals, but using these robots instead,” he said. “So there are a lot of technologies and open interesting scientific questions that are really what drives us on a day to day basis.”

    The latest study by the University of Florida has found that eating from smaller, less beautiful, and even paper plates will help prevent overeating. Eating with a fork instead of a spoon can help you lose weight, the researchers say. Much to their surprise, they find that putting mirrors in the dining room will also help reduce weight.

    The researchers asked 185 college students to choose a chocolate cake or a fruit salad, and evaluated the taste. Those who ate in a room with a mirror scored the taste of junk food much lower than those in a room without a mirror. But the taste of fruit salad remained the same in any case.

    Lead scientist, Dr. Ata Jami, says that a glance in the mirror tells people more than just about their physical appearance. It enables them to view themselves objectively and helps them to judge themselves and their behavior in the same way that they judge other people.

    The mirrors were found to push people to compare and match their own behavior with accepted social standards. The researchers believe it proves that people don't want to look in the mirror when they feel they are following the social standards. When they look in the mirror with mouths full of junk food, feelings of discomfort and failure can be increased. Therefore, the presence of the mirror lowers the taste of unhealthy food.

    However, researchers say this is only the case if people select the food they are eating, because they are responsible for that choice. The researchers suggest that mirrors be placed in dining rooms and other eating spaces, so that people will start eating more healthily.

    Hotshot jet pilots are no match for cliff swallows. The birds rocket over bridges and skim over lakes, rushing forward at accelerations that would knock an Air Force. By tracking these contests with high-speed cameras, a new study gives the first, in-depth peek into avian aerodynamics (鸟类空气力学) in the wild. "The findings may even provide insight into how to design better micro air vehicles-tiny drones. This technology will be brilliantly useful," says biomechanics expert Jim Usherwood of the United Kingdom's Royal Veterinary College in Hatfield. "High-resolution field studies like this have never been done before for birds."

    For cliff swallows, the trouble starts when they return from wintering in South America to their summer homes in North America. After arrival, they seek out their old mud nests—usually located under concrete bridges and freeways-and start rebuilding their homes. But rather than hunt down a fresh supply of mud, some swallows prefer stealing supplies from their more hardworking neighbors. Others take things further and will even lay an egg or two in their neighbor's nest before taking off.

    Battles in the air follow if the invaders are caught in the act, and a new study takes advantage of these fights to learn how birds perform high-speed maneuvers (演习). The team placed three cameras along a North Carolina lake crossed by a highway bridge that houses several cliff swallow nests and waited for the battles to commence.

The team was surprised to learn that most of the time, chasers copied the move of fleeing invaders. Swallows also pull very hard turns to escape an enemy, with one extreme case reaching 7.8 gravity. Fighter pilots usually pass out at about 5 or 6 gravity, which is why these experiments have earned interest, and partial funding, from the Office of Naval Research. The Navy may use the findings to build better guidance systems for micro air vehicles. However, the swallows' biomechanics are complex, and now the team is simply trying to collect a few tricks.

    Wolves strike fear into the hearts of many species, humans included. Our fear of them has brought them to the edge of dying out, as we have cruelly killed them as competitors and trouble-makers. But researchers are discovering that the very fear they put into prey（被捕食者）species is exactly what helps make ecosystems（生态）healthy.

    Yellowstone National Park is a typical example of just how wolves can help repair an ecosystem. An October 2018 study analyzed 40 years of research on large animals inside the park.

    "Yellowstone has benefited from the reintroduction of wolves in ways that we did not anticipate, especially the complexity of biological interactions（互动） in the park," explained Mark Boyce, a professor in the Department of Biological Sciences." We were really surprised at that and we'd never have seen these responses if the park hadn't adopted ecological-process management—allowing natural ecological processes to take place with least human intervention."

    After the wolves were re-introduced at Yellowstone, willow and cottonwood trees increased in number. The population of bears and bison also rose and what was once a ruling deer-wolf interaction is now more diverse.

    To learn more about just how wolves are beneficial, a short documentary from Quest explains how the presence of wolves influences the behavior of deer, which eventually makes entire ecosystems more biologically diverse and healthy. In this documentary, biologist Aaron Wirsing explored why wolves and other top predators （捕食者）were needed for diverse ecosystems to develop. Using a simple video camera, Wirsing is gaining a unique view point on predator-prey relationships and changing the way we think about wolves.

    The research is one more piece of evidence for why protecting these top predators is important not just for wolves as a species, but for hundreds of species at every level of an ecosystem. The fear they bring along may be the very angle that helps save them from dying out.

    It was once common to regard Britain as a society with class distinction. Each class had unique characteristics.

    In recent years, many writers have begun to speak the 'decline of class' and 'classless society' in Britain. And in modern day consumer society everyone is considered to be middle class.

    But pronouncing the death of class is too early. A recent wide-ranging society of public opinion found 90 percent of people still placing themselves in particular class; 73 percent agreed that class was still a vital part of British society; and 52 percent thought there were still sharp class differences. Thus, class may not be culturally and politically obvious, yet it remains an important part of British society. Britain seems to have a love of stratification.

    One unchanging aspect of a British person's class position is accent. The words a person speaks tell her or his class. A study of British accents during 1970s found that a voice sounding like a BBC newsreader was viewed as the most attractive voice, Most people said this accent sounded 'educated' and 'soft'. The accents placed at the bottom in this study, on the other hand, were regional city accents. These accents were seen as 'common' and 'ugly'. However, a similar study of British accents in the US turned these results upside down and placed some regional accents as the most attractive and BBC English as the least. This suggests that British attitudes towards accent have deep roots and are based on class prejudice.

    In recent years, however, young upper middle-class people in London, have begun to adopt some regional accents, in order to hide their class origins. This is an indication of class becoming unnoticed. However, the 1995 pop song 'Common People' puts forward the view that though a middle-class person may 'want to live like common people' they can never appreciate the reality of a working-class life.