VOA标准英语2010年-Our World — 13 March 2010（在线收听） |
VOA's weekly science and technology radio magazine Art Chimes | Washington, DC 12 March 2010 Related Links This week on Our World: A study of the UN climate change agency ... clothing that carries electric current ... and the challenge of archiving virtual worlds ... McDONOUGH: "if we don't work to preserve this stuff now, it's so subject to change and deterioration, we're just not going to have it accessible unless we put in very proactive efforts to try to keep it around." I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
The United Nations has asked an association of the world's leading science academies to review how the U.N.'s climate science group does its work. The Intergovernmental Panel on Climate Change, or IPCC, has admitted its last report, in 2007, made mistakes — exaggerating the extent of glacial melting in the Himalayas. The chairman of the Nobel Prize-winning IPCC, Rajenda Pachauri, spoke to reporters this week. PACHAURI: "In recent months we have seen some criticism. We are receptive and sensitive to that, and we are doing something about it. The review comes at a difficult time for researchers working on the issue. Climate change skeptics have also gotten ammunition from emails in which scientists discuss manipulating data to strengthen the case for global warming. The U.N. review will be conducted by the InterAcademy Council, which includes science academies in Britain, the United States, China, and many other countries. The council's co-chair, Robbert Dijkgraaf, said the IPCC's work will be reviewed to ensure it provides a good basis for action by policymakers. DIJKGRAAF: "Our goal will be to assure nations around the world that they will receive sound scientific advice on climate science with which governments and citizens alike can make informed decisions." He said the review process would be completed by the end of August, ahead of the IPCC's next meeting, in October. The review will apparently focus more on the process of gathering and analyzing information, rather than on the conclusions drawn in the last IPCC report, which were underscored this week by U.N. Secretary General Ban Ki-Moon. BAN: "Let me be clear: the threat posed by climate change is real. Nothing that has been alleged or revealed in the media recently alters the fundamental scientific consensus on climate change." Nevertheless, even a review by top scientists isn't likely to end criticism of the climate change consensus. Risk in Donating Kidney Comparable to Driving a Car Thursday was World Kidney Day, aimed at increasing awareness of kidney disease and conditions that can lead to kidney failure, such as high blood pressure and diabetes. Too often, patients with advanced kidney disease die while waiting for a transplant. Kidneys can come from a cadaver or from a living donor; we can survive very well, thank you, with just one of our two kidneys. But many would-be donors understandably worry about their own health. Now, as we hear from reporter Philip Graitcer, a new study has found no evidence that kidney donors lower their life expectancy. GRAITCER: Kidney disease has become a worldwide epidemic, affecting tens of millions of people. It can be treated with regular dialysis, but the only cure is a new kidney. However, getting a kidney from a deceased donor — the usual source — is a long and uncertain process. SEGEV: "You get put on a waiting list with over 80,000 other people and you wait for a kidney from a deceased donor to become available. In many places in this country those waiting times are from five to ten years long." GRAITCER: Transplant surgeon Dorry Segev notes that many patients die before a suitable kidney becomes available. That's why more patients are turning to healthy family members or friends who agree to give up one of their kidneys. With a living donor, the patients can be transplanted immediately. But every surgery entails risk, and doctors have been unable to give prospective living kidney donors accurate estimates of their chances of dying from the operation. SEGEV: "Our ability to estimate the risk was limited to small studies that were done at single transplant centers and were limited to studies done by reports of the transplant centers in terms of the outcomes." GRAITCER: So Segev and his colleagues at Johns Hopkins University Hospital undertook a nationwide study to try to quantify the mortality risks for living kidney donors. They used data from every U.S. transplant center, and the numbers were reassuring. SEGEV: "We found the estimated risk of dying from the operation of donating your kidney is 3 in 10,000. That's about the same risk as what you would take on from driving a car for your life." GRAITCER: And, he adds, they found no increased risk after the operation, either. SEGEV: "We were able to show when we matched people who donated a kidney to those who looked just like them were healthy but didn't donate a kidney, that there was no increase risk of death long term after donating a kidney. And we were able to find people for up to 15 years following their donation." GRAITCER: Segev says these findings should be reassuring for living kidney donors and transplant doctors, too. I'm Philip Graitcer. Scientists Study Fruit Flies for Clues to Human Memory A few days from now, how much of this show will you remember? Researchers have been studying memory for years. What goes on in our brains that allows us to remember our favorite song, or our cousin's wedding, or how to get to work? At a research center in Florida, scientists are looking for the answers in the brains of tiny insects. Mary Saner reports. SANER: At Scripps Research Institute in Jupiter, Florida, scientists are working to find clues about how the human brain processes memories. Their laboratory test animal is not a chimp or a dog or a rat that we know can remember things. It is the common fruit fly. Ron Davis, who chairs the Department of Neuroscience at Scripps Florida, explains why the fruit fly's brain has some ideal properties for human brain research. DAVIS: "They're relatively simple; the brain of the fruit fly has about 100,000 neurons. The brain of a human has about 100 billion neurons, and that's an enormous network of interconnected neurons in the human brain, if one thinks about it. We literally can't wrap our brains around the human brain yet." SANER: Researchers can remove a fly's brain and place it — still functioning — under a microscope. They can isolate neurons that have different functions and watch them fire, or send signals, to other neurons when stimulated. In one set of tests in the lab, fruit flies are trained to remember an odor associated with an unpleasant electrical shock. DAVIS: "These are Plexiglas tubes and they have an electrifiable copper grid on their surfaces. And so one puts the fly in these tubes first, passes an odor through the tube. Odor A shocks the animal, [giving it a] mild electric shock when odor A is apssed through. Then one takes the tube and passes fresh air through to clean it, and one takes the second odor, odor B, passes it through the tube and the animals are not shocked. They'll learn that one odor is bad because it's been punished in the presence of that odor. And the other odor is okay." SANER: Then, the fruit flies are tested to see how well they remember which is which. Davis says about 90 percent avoid the electric shock. The ones that don't are isolated, so their genes can be studied. Fruit flies have essentially the same genes as we do, just fewer of them. Davis says that correlation is what makes his research so promising. DAVIS: "If we find a gene in flies that's important for a process like memory formation, that sequence of that gene is generally conserved. We can use that gene to identify a similar gene in a mouse or in humans, because they have a very, very high sequence similarity. The bases that make up the gene are very similar. So we're actually quite similar to a fruit fly, believe it or not. (Laughter)" TEXT: Fruit flies have a very short lifespan compared to other laboratory animals like the mouse or rat. So, with the flies mating and reproducing every 2 weeks, many generations of flies can be studied in a year, allowing researchers to do genetic studies quickly. And since the flies are small, hundreds of thousands of them can be stored easily and inexpensively in plastic vials. Davis shows off a small room at the Institute, filled with vials of fruit flies — all to be used in the search for answers to how our memories are made and stored. DAVIS: "If one examines the vast majority of neurological diseases — Alzheimer's, Parkinson's, and so forth — and psychiatric diseases — schizophrenia, autism — all of these have a commonality in that they have learning disorders, in general, or memory formation seems to be an underlying feature of the vast majority of neurological and psychiatric diseases." SANER: Davis and his team of researchers hope their work will lead to a drug — a cogno enhancer — that will help the brain fight learning and memory related diseases. He says gaining a fundamental understanding of how the learning process works could be the key to treating — and perhaps curing — them. For VOA News, I'm Mary Saner in Jupiter, Florida Website of the Week Features Help for Your Mental Well-Being Time again for our Website of the Week, when we showcase interesting and innovative online destinations. Natural disasters like January's devastating earthquake in Haiti can produce tremendous loss of life and property. And for survivors — as well as family and friends halfway around the world — the stress and worry can take a psychological toll. Mental health can be at stake in less dramatic circumstances, too. The loss of a job or a divorce can trigger stress. Even just getting old can lead to depression. Our Website of the Week may help. BOSSOLO: "The APA Help Center is an online resource for consumers that features information related to psychological issues that affect people's daily physical and emotional well being." Luana Bossolo is a spokeswoman for the American Psychological Association. Their Help Center website at apa.org/helpcenter has a collection of tools and articles to help you learn about mental health issues and perhaps help you cope. The site includes sections on work and family, and on disasters. There's even a special interactive feature showing how stress can affect your physical health. A visit to the APA Help Center isn't the same as seeing a trained psychologist, but it's a good place to learn more about what's bothering you. BOSSOLO: "This is information, it's a starting point for people. This is a place for you to get more information. But if you feel that having information is not enough, then we really encourage people to seek appropriate help." Bossolo says the information on the site is vetted by knowledgeable psychologists to ensure it's accurate and reliable. Many mental health issues cross cultural boundaries. So, although the APA Help Center is sponsored by the American Psychological Association, international users account for one in five visits — some of them, presumably checking out the Spanish language version that's there, next to the English language site at apa.org/helpcenter, or get the link from our site, VOAnews.com. MUSIC: Ali Friend — "Chasing Milk Floats" You're listening to Our World, the weekly science and technology magazine from VOA News. I'm Art Chimes in Washington. Scientists Develop Fabric That Can Power Music Player, Monitor Vital Functions Imagine wearing a shirt that can power an MP3 player or cell phone, and monitor your heart beat, brain waves, and more. American and Italian scientists have invented a fabric that can conduct electricity but that also can be made into light, comfortable clothing. VOA's Jessica Berman reports. BERMAN: The new, high-tech fabric contains cotton threads coated with a thin layer of semiconductor polymers and nanoparticles which conduct electricity like metal wires. But one of the developers of the new fabric, Juan Hinestroza of Cornell University in New York says at first glance it's hard to tell the difference between plain cotton and cloth sewn with the conductive thread. HINESTROZA: "They will bend the same, they will drape the same, they will feel the same. Now if I put electricity through one of them, then you will see the difference." BERMAN: During the day, Hinestroza says tiny solar power cells embedded in the fabric collect energy and store it in a device similar to a double-A battery. The conductive thread, which is woven through the cotton fabric, is attached to the battery and power is discharged through a USB interface. Hinestroza says the conductive thread is so pliable and durable it can be sewn into any fabric with a sewing machine. Scientists are investigating other applications for conductive fabric, such as monitoring critical bodily functions. BERMAN: Hinestroza says monitoring heart rate and other vital bodily functions requires that the conductive threads be woven into dense grids in special, flexible fabrics. These patches of conductive material can then act as electrical sensors to detect the vibration from a pulse and breathing, or as electrodes to monitor brain waves like an EEG machine( electroencephalogram. Hinestroza says it's up to private companies now to develop specific applications for conductive fabric. HINESTROZA: "It will open a complete new way of possibilities of embedding sensors in bedding sheets, or in clothing or in shoes or in curtains, carpets. And the sensors will be part of the item of the fabric and that's the main difference. Instead of having a foreign object acting as a sensor, the sensor is a fiber and it's a natural fiber. It's not a synthetic one." BERMAN: While it's too soon to predict when the first high-tech garments will be available, Cornell University's Juan Hinestroza expects the first of many applications using electrically conductive thread will be ready for the market in the near future. Jessica Berman, VOA News, Washington. Preserving Digital Worlds; or, Giving More Life to 'Second Life' And finally today ... More than 2,000 years ago, the Library of Alexandria gathered the world's culture, written on papyrus scrolls and other materials. Today, libraries and archives are doing much the same thing for our modern culture, storing books and manuscripts, microfilm and maps, phonograph records and video tapes. And increasingly, the world creates and stores its culture in digital form. It's a big enough challenge to preserve the digital storage device; floppy disks and flash drives aren't made to last for decades, let alone centuries. And you also need hardware and software to retrieve the information. The challenge is even greater when what you want to preserve isn't a document or a software program, but an entire virtual world — like the game World of Warcraft, or Linden Lab's Second Life, or even things like training simulations or educational games. Now, a new initiative called Preserving Virtual Worlds is trying to see what can be done about it. Prof. Jerry McDonough is heading up the project at the University of Illinois. McDONOUGH: If you take a book and go and put it on a shelf and walk away for 70 years and come back, the paper may have decayed a little bit. It may be showing age, be a little brittle. But you're still going to have a book there. If you take a piece of modern software and put it on a shelf and come back 70 years later, you're not going to have anything that anyone can read. The media itself is not designed to last for that period of time. And we also have problems around just the media devices [changing]. Q: And then when you talk about virtual worlds, you've got a whole additional layer of challenges. McDONOUGH: Right. So some of the virtual worlds we're looking at, a game such as Doom for old DOS-based systems, that's fairly complex software, but it's still used on a single, standalone machine. But if you compare something like that to a world like Second Life, you're talking a massive distributed world, with the user base in the millions — trying to preserve something like that is sort of akin to being told, we need you to go out and preserve the state of New York. (laughs) You're really confronted with an issue of, where do we start and in many cases you also have issues of both legally and morally, what should we be trying to preserve here and what shall we say. You know, there are privacy issues or legal issues, and we have to just avoid this. So if we want to try to preserve something like an island in Second Life, we have to identify the copyright holders, we have to go and talk to them to obtain their permission to archive the material. So you can get into quite a lengthy series of negotiations with many, many parties to try and archive something like Second Life. Q: Are there some virtual worlds that are simply going to be too complex to feasibly preserve in any coherent way? McDONOUGH: There are some where you have to be very careful about the arrangements and who's involved in trying to archive it. So I mentioned Second Life. We are engaged in negotiations with content producers and copyright holders in those islands to try to grab their content. As a third party, there are limits, actually, on what we can copy out of Second Life. [Second Life developer Linden Lab] can actually go and access that material. The issue there is, they are a commercial enterprise that like many commercial enterprises is trying to make a profit. Long term preservation for cultural purposes is not actually part of their main mission statement. So there's a lot of work that's going to have to be done, figuring out how we as a society want to divvy up the responsibility for trying to preserve some of this content, trying to make arrangements that actually allow this material to be sustained over time. Q: So about this point in the conversation I can hear somebody wondering, what's the point of this? Why is it necessary or desirable to save this little bit of our culture. It's just an entertainment and 50 years from now or 100 years from now, aside from a few old folks being nostalgic, who's going to care? McDONOUGH: Well, there's a tendency to dismiss aspects of popular culture as unimportant, but really this is part of the history of who we are. And it says a lot to be able to look back at these older materials to understand what life was like at the time, what did people find interesting, what sorts of political messages, social messages got conveyed through these media. And if we don't work to preserve this stuff now, it's so ephemeral, it's so subject to change and deterioration, we're just not going to have it accessible unless we put in very proactive efforts to try to keep it around. MUSIC: "Our World" theme That's our show for this week. Please stay in touch. You can email us at [email protected]. Or write us at — Our World Our program was edited this week by Faith Lapidus. Bob Doughty is the technical director. And this is Art Chimes, inviting you to join us online at voanews.com/ourworld or on your radio next Saturday and Sunday as we check out the latest in science and technology in Our World. |
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