The researchers created a long-termstudy in which they invited families in 16 school districts in central Pennsylvania to participate. In each family, a teenager, a younger sibling, their mother and their father were interviewed at home and then asked about their activities and self-worth five times over a period of seven years.

    The study authors were surprised to discover that when fathers spent more time alone with their teenagers, the kids reported they felt better about themselves. Something about the father's role in the family seemed to improve self-esteem among the teenagers in the study, said study author Susan McHale, a professor of human development at Pennsylvania State University.

  “Time spent with Dad often involves joking, teasing and other playful interactions. Fathers, as compared to mothers, were more involved in leisure activities and had more friend-like interactions with their children, which is crucial for youth social development,” the study showed.

    But Marta Flaum, a psychologist in Chappaqua , New York, said, “How these findings reflect the real world is areal question. The sample in the study is so small and so unrepresentative of more families in the country today that I'm not sure how much we cangeneralizing from it. In my community, in Westchester County, I don't see parents and teenagers spending much time together at all. Parents are often working so hard and have less time to be together with their kids.”

    However, Flaum encourages parents to make time for their kids no matter how much work they have to do. “Research like this reminds us of how important it is. The time we have with themis so short, ” she said.

    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 integrated 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 (元件),” 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 together the components. “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, but 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.

    While this first robotic flyer is linked to a small, off-board power source, the goal is eventually to equip it with a built-in power source, so that it might someday perform data-gathering work at rescue sites, in farmers' fields or on the battlefield. “Basically it should be able to take off, land and fly around,” he said.

    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.”

    Today Dante had a small skating competition in his class. Before we went to the competition, I asked him if he wanted to wear something nice for the competition and he said, “Who cares? It's not important.” When we showed up at the rink(溜冰场), we found that most of the kids were dressed up. One boy who was around nine years old was my son's friend, wearing a dress shirt and a pink vest. I walked over to his mother saying how beautifully dressed he was. But his mother said, “He didn't want to dress up. He said that this competition was not important for him to dress up.”

    I thought it was interesting that neither Dante nor his friend viewed the competition as important and neither wanted to dress up. I started to wonder if this was how a child learned what was “important” and what wasn't.

Interestingly, this boy won two medals and Dante won none.

    Parents and teachers often instill (灌输) what they think is important: then children will accept the opinions of the adults. Gradually, they grow up stressing about how they look, how many medals they get, what color the medals are, how good their grades are, what a great “job” they can get in life, what a big house they can live in... etc.

    Dante taught me an important lesson today. He taught me what was unimportant. Life goes on long after the medal ceremony whether you win a medal or not.

    In Alaska, the US, the grizzly bears are not alone because of Timothy Treadwell. Everyone knows that grizzly bears can be very dangerous to people. However, people can be perilous to grizzly bears, too, because their fur and food are beneficial for some people. In fact, half of the grizzly bears die before they are five years old, even though they can live for about 30 years.

    Grizzly bears hibernate every winter. They sleep for several months. During this period, they don't wake up or eat anything. When they wake up in the spring, the grizzlies are in danger. But Timothy can protect them. He sleeps in a tent near the bears and bathes in a river with them. People do not hurt the bears when Timothy is with them.

    Timothy went to Alaska for the first time about 17 years ago. He was attracted by the beauty of the land and the prettiness of the animals. When he learned that people kill many grizzly bears every year, Timothy determined to protect the grizzly bears and to keep the bears safe from danger, so he lives with the bears for four to five months every year. At the beginning, Timothy's parents didn't agree, but later, they firmly supported him to do so, because they also wanted to protect bears as him.

    Timothy has lived with the grizzlies every spring for about 17 years. Some bears are now his friends. He gave them names. His friend Booble sometimes gives him fish which he likes. His friend Lazy sleeps near his tent every night. Every winter, when the bears hibernate, Timothy returns to his home in California. Then he teaches children and adults about his friends in Alaska.

    A good disguise keeps you hidden, right? Well, sometimes the best disguise is actually the most dazzling because research reveals that flashy metallic iridescence(金属彩虹色) can visually puzzle predators, which allows colorful prey to survive another day. Those surprising results appear in the journal Scientific Reports.

    Shining iridescent color, which changes depending on the angle from which it's viewed, is favored by everything from birds to beetles and blossoms to butterflies.

    "And in our research group we are of course interested in why this vivid metallic color is so widespread in nature." Karin Kjernsmo of the University of Bristol adds that in some cases the showy splashes of light are a sexual strategy. " Here I would like to point out that in some species, particularly those that display strong sexual dimorphism(雌雄两性), such as birds of paradise or some butterflies or fishes, the occurrence of iridescence is most likely driven by sexual selection. For example, in many of these cases it is the males that have these vivid iridescent colors and they use them in mate choice or they use them as a signal to attract mates."  But iridescence also shows up in situations where reproduction is not an issue. " So what we are studying now is whether natural selection imposed by predation(捕食行为) could explain the occurrence of iridescence in prey animals."

    The idea that eye­catching colors could be used as a cover­up isn't a new one." The father of camouflage theory, Abbott Thayer, really believed that iridescence should be categorized as a camouflage strategy. And he wrote in his famous lifework Concealing­Coloration in the Animal Kingdom, already in 1909, that 'brilliantly changeable or metallic colors are among the strongest factors in an animal's concealment'. And this sounds like a completely unreasonable thing to say, because how can colors that are both brilliant and changeable contribute to animal's concealment？"

    "In a similar way, we were asking whether iridescence, due to its changeability, could work as a form of camouflage by preventing shape recognition." Kjernsmo and her colleagues trained bumblebees to associate a particular shape—a circle or an oval—with a sugar reward. And they found that the bees, when given a choice, would preferentially visit the shape they knew to be sweet. But when the shapes were iridescent, the bees had trouble telling them apart. "It seemed that the strikingly iridescent surfaces on our targets visually broke up the otherwise recognizable shape of the targets, which made them hard to distinguish." As for making use of this method for hiding in plain sight, "Any practical applications is of course directly linked to any industry that has an interest in camouflage, that is how to conceal objects or make them more difficult to recognize." The researchers are currently conducting experiments with birds, which often prey on iridescent insects to see if it helps to have a bird's­eye view.

Planning Your Family Trip

    Plan ahead to make your family trip run smoothly. Family vacations are cherished memories. Keeping children entertained on the road or during a flight, however, can be challenging. The best way to cut down on anxiety? Plan ahead.

    Avoid giving children snacks that contain sugar and caffeine. Sweet treats keep them happy and quiet for five minutes, as it fills them with unusable energy that will turn into crankiness (偏执) when the sugar wears off. Bring fun, small snacks like flavored baked chips, apple sauce, raisins, and granola bars—and top it off with a little protein like cheese sticks to keep the blood sugar levels nice and steady.

    Bring plenty of plastic or paper bags. This is the perfect time to put those spare bags around the house to use. Store them in your purse or pocket, as well as in the car. This is a quick solution for garbage, diaper wrapping or motion sickness.

    Avoid extra costs on bulk items you will need during the trip. When flying, purchase bulk items like diapers, formula, and wipes at your destination. In the past, it was convenient and free to check these items. Now, each checked luggage item costs $25 or more on average. When driving, do the opposite; take your bulk items to avoid extra trips to the store when you arrive, which can help you avoid impulse travel purchases.

    Bring a full change of clothing for each child. Keep these items within fairly easy reach. When a spill or mess happens, this will help parents avoid unexpected (and unbudgeted) clothing purchases.

    Travel planning can help make family vacations what they are supposed to be: Fun! What are some of your favorite strategies for saving time and stress while traveling with children?