I am peter Hodes ,a volunteer stem courier. Since March 2012, I've done 89 trips of those , 51 have been abroad, I have 42 hours to carry stem cells（干细胞）in my little box because I've got two ice packs and that's how long they last, in all, from the time the stem cells are harvested from a donor(捐献者) to the time they can be implanted in the patient, we've got 72 hours at most, So I am always conscious of time.

I had one trip last year where I was caught by a hurricane in America. I picked up the stem cells in Providence, Rhode Island, and was meant to fly to Washington then back to London. But when I arrived at the check-in desk at Providence, the lady on the desk said: “Well, I'm really sorry, I've got some bad news for you-there are no fights from Washington.” So I took my box and put it on the desk and I said: “In this box are some stem cells that are urgently needed for a patient-please, please, you've got to get me back to the United Kingdom.” She just dropped everything. She arranged for a flight on a small plane to be held for mere-routed(改道)me through Newark and got me back to the UK even earlier than originally scheduled.

For thiscourier job, you're consciously aware than that box you're got something that is potentially going to save somebody's life.

    Technology is the application of knowledge to production. Thanks to modern technology, we have been able to increase greatly the efficiency of our work force. New machines and new methods have helped cut down time and expense while increasing overall output. This has meant more production and a higher standard of living. For most of us in America, modern technology is thought of as the reason why we can have cars and television sets. However, technology has also increased the amount of food available to us, by means of modern farming machinery and animal breeding techniques, and has made our life span longer via medical technology.

    Will mankind continue to live longer and have a higher quality of life? In large measure, the answer depends on technology and our ability to use it widely. If we keep making progress as we have over the past fifty years, the answer is definitely yes. The advancement of technology depends on research and development, and the latest surveys show that the united States is continuing to put billions of dollars annually(每年) into such efforts. So while we are running out of some limited resources, we may well find technological substitutes (代用品) for many of them through our research programs.

    Therefore, in the final analysis, the three major factors of production (land, labor and capital) are all influenced by technology. When we need new skills or techniques in medicine, people will start developing new technology to meet those needs. As equipment proves to be slow or inefficient, new machines will be invented. Technology responds to our needs in helping us improve our standard of living.

    Believe it or not, the size of the human brain has become smaller over the past 20,000 years. Scientists argue over whether this means we are becoming more or less intelligent as a species.

    “I'd call that a major downsizing in an evolutionary eye blink (眨眼),” John Hawks told Discover magazine.

    Why is the brain becoming smaller?

    There are different theories to explain it. One is that tens of thousands of years ago, before the decline began, to survive in cold and dangerous conditions, humans needed a stronger and larger body and therefore, a larger head. Also they had to chew the tough meat of rabbits, foxes and horses. As conditions improved, the brain stopped growing, according to supporters of this theory.

    Another theory comes from a recent study by David Geary and Drew Bailey. They found that brain size decreased as population density(密度) increased.

    “As complex societies appeared, the brain became smaller because people did not have to be as smart to stay alive.” Geary told AFP.

    But smaller brain size does not necessarily mean that modern humans are less smart than their ancestors. “Modern humans simply developed different, more complex forms of intelligence,” said Brian Hare.

    Hare's studies focus on two types of great apes: chimpanzees and bonobos. Both are much like humans, but are physically quite different from one another. The bonobo has a smaller brain than the chimpanzee, and is also much less aggressive and more tolerant.

    “When it comes to working out a problem,” Hare said, “chimpanzees are much less likely to accomplish it if it involves working together. Not so with bonobos.”

The smaller brain in modern humans may be evidence that we can cooperate,” Hare told the US National Public Radio.

    It's well-known that meditation (冥想) has many benefits, but do you know how to practice it for a beginner?

    Set a proper scene

    Find a space for meditation. It should be private and quiet. Make sure the temperature is comfortable. Sit on a cushion (垫子) if the floor is uncomfortable. You may play soft music if you like.
                   

    Take a moment to loosen up. Remember that the goal of meditation is to relax. Loosen your clothing, remove your shoes and have a good stretch. Do your best to ease any muscle tension that might keep you from achieving relaxation. Make an effort to relax your facial muscles.

    Focus on your breath

    Sit down in the space you've prepared. Close your eyes and breathe. Each time you breathe in, count “one”. Each time you breathe out, count “one”. The idea is to strengthen being in the moment — the last breath doesn't matter, and the next one doesn't matter; only this one matters.

    Feel your breath inflate (胀大) your lungs and push on your diaphragm (隔膜). Feel how sweet it is to inhale the fresh air. As you do this, your body will gradually begin to relax and all of your attention will be centered within your mind.

    Return to real life

    Once you feel fully centered in your mind, allow yourself to gradually drift back to real life. Move your fingers and toes and slowly wake your body up. Open your eyes and remain there for a few minutes until your senses come back, and then slowly stand up.

    Even if you can't make it fully into your mind, you still get some benefits from it. If you want to feel better, you just need to practice. Set about 10 minutes around the same time every day and repeat this exercise.

    Dutch officials toasted on Tuesday the opening of what is being called the world's first 3D-printed concrete bridge, which is meant to be used by cyclists. There was applause as officials wearing hard hats and workmen's jackets rode over the bridge on their bikes at the opening ceremony in the southeastern town of Gemert.

    “The bridge is not very big, but it was rolled out by a printer which makes it unique,” Theo Salet, from the Eindhoven University of Technology, told Dutch broadcaster NOS. Work on printing the bridge, which has some 800 layers, took about three months after starting in June and it is made of pre-stressed concrete, according to the university. “One of the advantages of printing a bridge is that much less concrete is needed than in the conventional technique in which a mould (泥浆) is filled,” it said on its website, adding “a printer deposits the concrete only where it is needed.”

    The eight-metre (26-foot) bridge crosses a water-filled channel to connect two roads, and it was tested for safety to bear loads of up to two metric tons in cooperation with the BAM Infra Construction company. Although designed for bikes, it could take up to 40 trucks, the designers said “We are looking to the future,” said the head of BAM, Marinus Schimmel. “3D printing meant fewer rare resources were needed and there was significantly less waste,” he added.

    The Netherlands is among countries, with the United States and China, taking a lead in the cutting-edge technology of 3D printing, using computers and robotics to construct objects and structures from scratch without using much traditional manpower. Last year a Dutch architect unveiled (提示) a unique 3D printer with which he hopes to construct an “endless loop” building. And a Dutch start-up called MX3D has begun printing a stainless-steel bridge, of which a third is already completed. The aim is to finish printing by March and lay the bridge over an Amsterdam canal in the future.

    Let children learn to judge their own work. A child learning to talk does not learn by being corrected all the time; if corrected too much, he will stop talking. He notices a thousand times a day the difference between the language he uses and the language those around him use. Bit by bit, he makes the necessary changes to make his language like other people's. In the same way, children learn to do all the other things without being taught to walk, run, climb, whistle, ride a bicycle…They compare their own performances with those of more skilled people, and slowly make the needed changes. But in school we never give a child a chance to find out his mistakes and correct them for himself. We do it all for him. We act as if we thought that he would never notice a mistake. If it is a matter in mathematics or science, give him the answer book. Let him correct his own papers. Why should we teachers waste time in such routine(日常的) work? Our job should be to help the child when he tells us that he can't find the way to get the right answer. Let the children learn what all educated persons must some day learn, how to measure their own understanding, how to know what he does not know.