"Over the years the unthinkable hasbecome thinkable and today we sense we are close to being able to alter humanheredity œ#)." These were the words of David Baltimore of the CaliforniaInstitute of Technology, on December 1st, when he opened a three-day meeting inWashington to discuss the morality and use of human gene editing. Dr Baltimoreis an old hand at these sorts of discussions, for he was also a participant inthe Asilomar conference, in 1975, which brought scientists together to discussa safe way of using the then-new tcchnology of recombinant DNA, and whoserecommendations influenced a generation of biotechnology researchers.

Four decades on, the need for a similarsort of chin-wag has arisen. The InternationalSummit on Human Gene Editing has been held by the national scientific academiesof three countries — America, Britain and China. They are particularlyconcerned about whether gene editing should be used to make heritable changesto the human germ line, something Dr Baltimore described as a deep andtroubling question. Like those of Asilomar, the conclusions of this meetingwill not be binding. But the hope is that, again like Asilomar, a mixture ofcommon sense and peer pressure will create a world in which scientists aretrusted to regulate themselves, rather than having politicians and civilservants do it for them. The meeting is being held against a backdrop of rapidscientific advance, Since 2012 research into a new, easy-to-use editing tool calledCRISPR-Cas9 has blossomed. This technique involves a piece of RNA (a chemicalmessenger, which can be used to recognise a target section of DNA) and anenzyme (酶)called a nuclease that can snip unwanted genes out and paste new ones in.

Public interest was aroused in April,when Chinese scientists announced they had edited genes in non-viable ( 无活力的) humanembryos, and again in November when British researchers said they hadsuccessfully treated a one-year-old girl who had leukaemia ( 白血病),using gene-edited T-cells. T-cells are part of the immune system that attack,among other things, tumour cells. The researchers altered T-cells from ahealthy donor to encourage them to recognise and kill the patient's cancer, tomake them immune to her leukaemia drug, and to ensure they did not attack herhealthy cells.

In another recent development, a firmcalled Edit as Medicine, which is based in Cambridge, Massachusetts, has saidit hopes, in 2017, to start human clinical trials of CRISPR-Cas9 as a treatmentfor a rare genetic form of blindness known as Leber congenital amaurosis (伯氏先天性黑蒙).Though other companies are already testing gene-editing therapies, these employolder, clunkier forms of the technology that seem likely to have lesscommercial potential. Moreover, researchers at the Broad Institute, also inCambridge, said this week that they had made changes to CRISPR-Cas9 whichgreatly reduce the rate of editing errors — one of the main obstacles to thetechnique's medical use.

On the subject of germ-line editing,Eric Lander, the Broad's head, told the meeting it would be useful only in rarecases and said it might be a good idea to "exercise caution? before makingpermanent changes to the gene pool. The need for caution is advice that mightalso be heeded by those pursuing work in animals other than people, and inplants — subjects not being covered by the summit.

    Mark Twain, the famous American writer and a great master of humor, liked to play jokes on others. But once a joke was played on him. One day Mark Twain was invited to give a talk in a small town. At lunch he met a young man, one of his friends.

    The young man said that he had an uncle with him. He told Mark Twain that his uncle never laughed or smiled, and that nobody and nothing was able to make his uncle smile or laugh.

    "You bring your uncle to my talk this evening," said Mark Twain. "I'm sure I can make him laugh."

    That evening the young man and his uncle sat in the front. Mark Twain began to speak. He told several funny stories and made everyone in the room laugh. But the man never even smiled. Mark Twain told more funny stories, but the old man still kept quiet. Mark Twain continued to tell his funny stories. Finally he stopped. He was tired and quite disappointed.

    Some days later, Mark Twain told another friend what had happened." Oh," said his friend, "I know that man. He's been deaf for years."

    Can small, organic agriculture really feed the world? Won't we need science to produce enough food as the world population is growing to 9 billion by 2050? The answer to both questions is YES—but that science may look different than you think.

    We've been told that the only way we'll be able to feed the growing population is through the science of GM(转基因) crops and chemicals. But the latest scientific studies are saying just the opposite. In study after study, the message about agriculture is: To feed the world, we need to support sustainable (可持续的) agriculture on different, local, family farms that work with nature.

    In 2008, an international study found that sustainable agriculture, not GM crops, shows more hope of ending hunger. The International Assessment of Agricultural Knowledge, Science, and Technology for Development (known as the IAASTD), calls for a change of the world's food and farming systems.

    The Assessment said that industrial agriculture has greatly destroyed the world's soils and other natural resources, and now is doing harm to water, energy, and weather safety. The report warns that expensive, short-term ways—including GM crops—are not likely to cut down long-term hunger, and could even make environmental and social problems worse in many places.

    A recent report by the UN Environment Program shows that food problems will become more serious because of environmental problems and strongly supports sustainable agriculture on small family farms. It also showed that a worldwide change to organics could actually increase the world's food production by as much as 50%—enough to feed a population of 9 billion people with the land we have now. GM crops, once popular, are now being questioned worldwide.

    Minutes after the last movie ended yesterday at the Plaza Theater, employees were busy sweeping up popcorns and gathering coke cups. It was a scene that had been repeated many times in the theater's 75-year history. This time, however, the cleanup was a little different. As one group of workers carried out the rubbish, another group began removing seats and other theater equipment in preparation for the building's end.

    The film classic The Last Picture Show was the last movie shown in the old theater. Though the movie is 30 years old, most of the 250 seats were filled with teary-eyed audience wanting to say good-bye to the old building. Theater owner Ed Bradford said he chose the movie because it seemed proper. The movie is set in a small town where the only movie theater is preparing to close down.

    Bradford said that large modem theaters in the city made it impossible for the Plaza to compete. He added that the theater's location (位置) was also a reason. "This used to be the center of town," he said. "Now the area is mostly office buildings and warehouses."

    Last week some city officials suggested the city might be interested in turning the old theater into a museum and public meeting place. However, these plans were given up because of financial problems. Bradford sold the building and land to a local development firm, which plans to build a shopping complex on the land where the theater is located.

    The theater audience said good-bye as Bradford locked the doors for the last time. After 75 years the Plaza Theater has shown its last movie. The theater will be missed.

    They are called "sea parrots", and sometimes "clowns (小丑) of the sea"!

    Atlantic puffins (海鹦) are small seabirds which are around 25 cm in length. They have black and white feathers and a large parrot-like beak (鸟喙). The beak changes color during the year. In winter, the beak has a dull gray color, but it turns orange in spring!

    Puffins spend most of their lives out at sea, resting on the waves when not swimming. They live on the eastern coast of Canada and the United States, and the western coast of Europe.

    Puffins live off small fish such as herring, hake and sand eels. Puffins flap (拍) their wings up to 400 times a minute and speeding through the air at up to 88 km an hour. Wow! What's more, puffins can dive down 60m under water in search of their favorite fish.

    In spring and summer, thousands of puffins stay together on the coasts and islands of the North Atlantic Ocean to start a puffin family. They usually pair up with the same partner as before some may have been together for 20 years! Puffins dig out a hole usually in a grassy bank. Both parents take it in turn to incubate (孵化) the egg for the next 36-45 days!

Although puffins are not classed as an endangered animal, their population in some places is becoming smaller. The main reasons are overfishing, which can lead to a shortage of food for puffins, and pollution—especially oil spills (溢出). Not only does the oil make these beautiful birds sick, it harms their feathers.

    A 27-year-old inventor, Joco Paulo Lammoglia, has come up with a new device ( 设 备 ) named the AIRE mask, which is capable of transforming the wind energy provided by the wearer's breath into electrical energy. This means breathing has become a source of renewable energy. The inspiration for the invention came from his watching children blowing on pinwheels (纸风车).

    The device is worn like a mask equipped with tiny wind turbines (涡轮) and it can work its magic even while people are sleeping, running or hanging around, since energy is created from one's breath. The principle of this AIRE mask is simple. The invention uses the wind flow created by breathing and changes it into energy that can charge mobile phones and iPods. Simply put this mask connected to your mobile phone on your face. The rest takes place naturally through your breath that provides power to run turbines which produce electricity.

    Lammoglia explained how useful he hopes the AIRE will become. He said, "I hope to bring the concept into production and reduce the carbon footprint. It can be used indoors or outdoors, while you're sleeping, walking, running or even reading books." Apart from saving energy and contributing to environmental protection, it also encourages the practice of physical exercise. This is an entirely all time renewable energy source. Its energy is available 24 hours a day, seven days a week.

    Lammoglia explained why he thought the AIRE was so useful, saying, "Though many of our modern devices offer benefits, they tend to consume a high amount of electrical energy. This may cause problems for the environment, especially if the energy used by these devices is produced by non-renewable sources.

    The AIRE mask will be future's cheaper source of charging mobile phones. It would save energy and allow people to never have to worry about their phone dying unless they stop breathing.