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.”

    The United Arab Emirates (UAE) is mostly a desert. However, this has not stopped the country from creating great building projects. On September 26, UAE officials announced another ambitious project — Mars Science City. Expansive deserts and miles of coastline provide plenty of options for safe rocket launches (发射). And its position on the Earth makes it especially appealing as the spin of the Earth provides an extra push, meaning less fuel is needed to get payloads into orbit. All these seem to make it possible.

    The Mars City Project, designed by Bjarke Ingels Group, or BIG, will provide a realistic model to simulate (模仿) living on the surface of Mars, the red planet. It is part of the UAE's Mars 2117 Project to lead the global race to land humans on Mars and be the first to build a settlement there. Sheikh Mohammed bin Rashid, Prime Minister and ruler of Dubai, says, “The UAE seeks international support to develop technologies that benefit humans, and lay the foundation of a better future for more generations to come.”

    Built outside Dubai, the 1.9 million square feet city is expected to cost $135 million. It will consist of several dome-shaped laboratories, similar to the ones imagined for the first Mars settlers. Scientists from around the word will be invited to conduct research to come up with methods to create food, water and energy, using techniques which can be copied onto the red planet. The living spaces, where the researchers can live for up to a year, will simulate the planet's conditions as much as possible.

    The research city will also include a museum featuring famous space achievements to help educate and inspire children to undertake space exploration and discovery. To discover whether the construction method works on Mars, the museum's walls will be 3D printed using the sand from the nearby desert. Now, if they would only add some living quarters for the general public to experience life on Mars without leaving Earth, life would be perfect.

    Grown-ups are often surprised by how well they remember something they learned as children but have never practiced ever since. A man who has not had a chance to go swimming for years can still swim as well as ever when he gets back in the water. He can get on a bicycle after many years and still ride away. He can play catch and hit a ball as well as his son. A mother who has not thought about the words for years can teach her daughter the poem that begins “Twinkle, twinkle, little star” or remember the story of Cinderella or Goldilocks and the Three Bears.

    One explanation is the law of overlearning, which can be stated as follows: Once we have learned something, additional learning trials will help strengthen the related knowledge and skills.

    In childhood we usually continue to practice such skills as swimming, bicycle riding, and playing baseball long after we have learned them. We continue to listen to and remind ourselves of words such as “Twinkle, twinkle, little star” and childhood tales such as Cinderella and Goldilocks. We not only learn but overlearn.

    The multiplication tables (乘法口诀表) are also an exception to the general rule that we forget rather quickly the things that we learn in school, because they are another of the things we overlearn in childhood.

    The law of overlearning explains why cramming for an examination, though it may result in a passing grade, is not a satisfactory way to learn a college course. By cramming, a student may learn the subject well enough to get by on the examination, but he is likely soon to forget almost everything he learned. A little overlearning, on the other hand, is really necessary for one's future development.

    The days of the hunter are almost over in India. This is partly because there is practically nothing left to kill, and partly because some steps have been taken, mainly by banning tiger-shooting, to protect those animals which still survive.

    Some people say that Man is naturally a hunter. I disagree with this view. Surely our earliest forefathers, who at first possessed no weapons, spent their time digging for roots, and were no doubt themselves often hunted by meat-eating animals.

    I believe the main reason why the modern hunter kills is that he thinks people will admire his courage in overpowering dangerous animals. Of course, there are some who truly believe that the killing is not really the important thing, and that the chief pleasure lies in the joy of the hunt and the beauties of the wild countryside. There are also those for whom hunting in fact offers a chance to prove themselves and risk death by design; these men go out after dangerous animals like tigers, even if they say they only do it to rid the countryside of a threat. I can respect reasons like these, but they are clearly different from the need to strengthen your high opinion of yourself.

    The greatest big-game hunters expressed in their writings something of these finer motives. One of them wrote.

    "You must properly respect what you are after and shoot it cleanly and on the animal's own territory(领地)。You must fix forever in your mind all the wonders of that particular day. This is better than letting him grow a few years older to be attacked and wounded by his own son and eventually eaten, half alive, by other animals, Hunting is not a cruel and senseless killing - not if you respect the thing you kill, not if you kill to enrich your memories, not if you kill to feed your people."

    I can understand such beliefs, and can compare these hunters with those who hunted lions with spears(矛) and bravely caught them by the tail. But this is very different from many tiger-shoots I have seen, in which modern weapons were used. The so-called hunters fired from tall trees or from the backs of trained elephants. Such methods made tigers seem no more dangerous than rabbits.

Training the Brain

    People who can accomplish unbelievable tasks, such as memorizing thousands of random numbers in under an hour, state that they just have normal brains. Some memory superstars compete in Olympic-like World Memory Championships. These mental athletes, or MAs for short, can memorize names of dozens of strangers in a few minutes or any poem handed them. Ed Cooke, a 24-year-old MA, explains they see themselves as participants rescuing the long-lost art of memory training. These techniques existed not to recall useless information, but to cut into the brain basic text and ideas.

    A study in the journal Nature examined eight people who finished near the top of the World Memory Championships. The scientists examined whether their brains were fundamentally different from everyone else's or whether they were simply making better use of memorizing abilities we all possess. They put the MAs and control subjects into brain scanners and had them memorize numbers and photographs. The result surprised everyone. The brains of the MAs and those of the control subjects were indistinguishable. On every test, the MAs scored in the normal range. However, when the scientists examined what part of the brain was used during a memory activity, they found the MAs relied more heavily on areas in the brain involved in spatial memory.

    MAs offer an explanation: anything can be fixed upon our memories and kept in order by constructing a building in the imagination and filling it with pictures of what needs to be recalled. Dating back to the fifth century, the building is called a memory palace. Even as late as the fourteenth century, when there were copies of any text, scholars needed to remember what was read to them. Reading to remember requires a different technique than speed reading. If something is made memorable, it has to be repeated. Until relatively recently, people read only a few books intensively (细致地) again and again, usually aloud. Today we read extensively, usually only once and without continuous focus.

    So the great difference is the ability to create impressive pictures in mind and to do it quickly. Using memory palaces, MAs create memorized pictures. For example, recombine the pictures to form unforgettable scenes such as the ways through a town. One competitor used his own body parts to help him memorize a 57,000-word dictionary.

    Anyone who wishes to train the mind needs first to create fantastical palaces in the imagination. Then they should cut each building into cubbyholes for memories. In a short amount of time, they will notice improvement with remembering things. To keep the skill sharp, MAs deliberately empty their palaces after competitions, so they can reuse them and they recommend that beginners do the same.

    Do you often feel like you want to wash your hands again and again? Or do you ever have the urge to line up the items on your desk? These all may be symptoms of obsessive-compulsive disorder (强迫症), or OCD, which affects about 2 percent of the world's population.

    Those who suffer from OCD have difficulty finding successful treatment because doctors don't clearly understand its causes. But now, a new study has given hope for a future cure.

    For the study, which was published in the journal Nature in October, researchers observed humans, dogs and mice. They discovered four genes that may be responsible for obsessive-compulsive behaviors in humans.

    But why observe dogs and mice to learn about humans?

    "Dogs, it turns out, are surprisingly similar to people," study author and geneticist Elinor Karlsson, of the Broad Institute of MIT and Harvard University, US, told NPR. "They're chasing their own tail or chasing shadows like normal, but they're doing it for hours."

    In the study, researchers made a list of about 600 genes in mice, dogs and humans that they thought might cause OCD, reported NPR. They then compared those genes in two large groups of people – those who don't have OCD and those who do. In the end, they identified just four genes with mutations (突变) in the OCD group. The genes are active in a neurological pathway (神经通路) in the brain, which is believed to help control actions. But the mutations could block the neurological pathway.

    For example, for people without OCD, when they finish washing their hands, a signal will come, telling them to stop. But for people with OCD, the neurological pathway is blocked, so the message isn't getting through. As a result, the person will continue to wash their hands.

    "OCD and anxiety are kind of like learning disorders," Marcos Grados, an OCD researcher at Johns Hopkins University School of Medicine, told NPR. "Often with OCD, people have a fear of germs (细菌). You can't touch tables or door knobs (把手) and every time it's the same sensation (感觉). You didn't learn that the last time you touched a door knob, nothing happened. It's like touching it for the first time ever."

    However, that doesn't mean people who have these genetic mutations will always have obsessive-compulsive behaviors, the researchers said. That's because the disorder also relies on other things, such as one's environment.

    According to reports, various existing treatment methods have low success rates in patients. But now that we know where OCD comes from, let's hope we will soon find an effective way to treat it.