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MUSIC: "Our World" theme
For public health officials, the possibility of a major outbreak of avian, or bird flu remains a big unknown as we move into the annual flu season. So far, the deadly H5N1 virus has not shown a capacity to spread easily from person to person, which experts say would be necessary to trigger a pandemic. That may not happen. But if the right mutation occurs in the virus, it could.
Scientists have tried to construct mathematical models to predict how a pandemic would spread, and how much damage it would cause. One study from Australia released earlier this year, for example, projected that even a mild pandemic could cost 1.4 million lives and cost a third of a trillion dollars in lost economic output. And that's the mild scenario. In developing this model, co-author Warwick McKibbin says he and his colleagues started with the known experiences in three 20th century pandemics.
McKIBBIN: "And this gives us a good initial condition to start with, and then we try and modify the historical experience for what we observe in the world today."
McKibbin admits that, like any model, this one has limitations, and Brookings Institution fellow Joshua Epstein says chief among them is with the fact that no one knows exactly which virus will trigger a pandemic.
EPSTEIN: "We just don't have this bug. When we have it, we won't know how it behaves in human hosts. We don't know how it would respond to anti-virual drugs. We won't have a vaccine. We don't know how people will behave. They may all go to the basement and protect themselves. They may all run around like maniacs and spread the thing. You know, there's just a huge amount we don't know."
Uncertainties aside, public health officials still must do what they can to prepare for a possible pandemic. The World Health Organization has called on all countries to develop a plan, though so far only 40 have done so. VOA's Rosanne Skirble reports on a new study of those plans, published in the journal PLoS Medicine.
SKIRBLE: Lead author Lori Uscher-Pines, a graduate student at Johns Hopkins University's Bloomberg School of Public Health, says priority-setting is the first step in global preparedness.
USCHER-PINES: "These flu plans are very dynamic documents and they are constantly being edited. So you see flu plans that are under 10 pages long and you see flu plans that slightly under 500 [pages]. And often they aren't adhering to World Health Organization guidelines on certain issues."
SKIRBLE: For example, Uscher-Pines notes, while health care workers consistently ranked at the top of the priority lists to receive antiviral drugs or vaccines, in almost half the plans children were next in line to receive the medications.
USCHER-PINES: "And the World Health Organization actually does not think that this is an appropriate strategy based on the evidence that is available. So the World Health Organization is saying that they advise against this, but we are still seeing countries do this in a pretty large scale, and we can only guess as to why this is the case, perhaps socio-cultural values or different interpretation of evidence."
SKIRBLE: Uscher-Pines says this finding suggests that public health plans must consider both scientific and ethical issues.
USCHER-PINES: "If the public is involved and can think about it in advance and perhaps knows first responders who'll be the first people to be prioritized, then when an event happens they will ask fewer questions. They will be less surprised. Maybe less panic will ensue as a result of the fact that this is something everyone has thought about in advance."
SKIRBLE: Lori Uscher-Pines says attention to these details may help reduce death and minimize political turmoil and claims of unfair treatment during an epidemic. I'm Rosanne Skirble.
Two new U.S. studies say the nutritional benefits of eating fish outweigh the potential hazards.
From Harvard University comes the conclusion that the health benefits of eating fish over-ride any concerns about toxic materials known to contaminate many ocean-caught species. Dariush Mozaffarian and colleagues reviewed previous studies analyzing the risk and benefits.
MOZAFFARIAN: "The benefits of eating fish are far greater than the potential risks. If you eat a fish and it has some mercury in it, you might be getting less benefit from that fish than if it did not have mercury in it, but the overall benefit is still positive."
The Harvard conclusions published in JAMA, the journal of the American Medical Association, were generally echoed by a separate report from the Institute of Medicine, part of the U.S. National Academy of Sciences. They convened a panel of top experts with the aim of helping consumers to resolve the conflict.
The committee concluded that most people should aim for two 85-gram servings of seafood a week, and if they eat more than that, they should choose a variety of seafood types.
There were more cautions recommendations for youngsters, and women who are or could become pregnant, or who are nursing. For the women, a reasonable amount would be two 85-gram servings of fish per week, with a maximum of 340 grams per week. They can consume up to 170 grams of white (albacore) tuna each week, but should avoid large predatory fish, such as shark or swordfish. Children should eat proportionately less. Committee chairman Malden Nesheim stressed the importance of fish with so-called omega-3 fatty acids — EPA and DHA — which have a variety of healthful effects.
The Harvard study found that including fish in your diet reduces your risk of death from heart disease by one-third, especially when the fish is high in omega-3 fatty acids. But the Institute of Medicine group, in their study, was unable to confirm that.
NESHEIM: "In the committee's judgment, age, gender, pregnancy and breastfeeding are factors that distinguish among the target groups who face different benefit-risk tradeoffs. And additional target group explored was individuals at risk for coronary heart disease, however the evidence is insufficient to warrant separate guidance for this group."
According to committee member Susan Krebs-Smith of the National Cancer Institute, the typical American diet does not include enough fish and seafood.
KREBS-SMITH: "I would say the average person can consume more fish than they do. I think average consumption is not up to the levels that we have allowed, and we think those levels are levels through which you can still manage the risks."
Although the panel's recommendations were specifically aimed at an American audience, Nesheim noted the global nature of the fish business, saying the same calculus of nutrition versus pollutants is likely to apply elsewhere, too.
NESHEIM: "The seafood trade is international, and so much of our seafood comes form sources around the world, and so markets for seafood in many parts of the world will have the same issues associated with them as the seafood we have in this country."
Malden Nesheim of Cornell University chaired the panel that's found the benefits generally outweigh the risks of eating most kinds of seafood.
Time again for our Website of the Week, when we showcase interesting and innovative online destinations.
Before search engines came along to tame the World Wide Web, users looking for specific information relied on directories — Yahoo was one of the best known — with categorized listings organized like a library: all the Chinese cooking sites listed on one page, programming utilities on another, and so forth.
A few years back, search engines — notably Google — leapfrogged over directories to become the main way of finding stuff online. But the directories never completely went away, and this week we highlight one of the most comprehensive.
KEATING: "The Open Directory Project is a volunteer-driven web directory that helps users navigate the Web. People from, really, all over the globe, contribute and edit categories in the directory and contribute links to really the quality websites across the web."
Bob Keating is Editor in Chief of the Open Directory Project, also known as DMOZ at dmoz.org.
Unlike Google, which relies on computer algorithms to help you locate the information you want, Open Directory uses 75,000 human editors — unpaid volunteers — to make sense of the vastness of the Web.
Although there are times when a search engine will be your best choice; other times, Keating says, choosing Open Directory will be a smarter way to find what you're looking for.
KEATING: "The web directory is good if you're looking to find information on a topic, and you just want to see what's out there, where a search engine is really most useful if you're looking for specific types of information."
In addition to subject categories, there are dozens of individual language categories.
Using volunteers makes Open Directory similar in some ways to a popular user-written online encyclopedia. And Keating says it gives Open Directory more scalability — the ability to grow — than a directory created by a paid staff.
KEATING: "The editor-contributor model like the Open Directory is similar to what you find today with Wikipedia and these other types of projects that have user-driven content. And the Open Directory was a precursor to those projects in that it was meant to be scalable by making it open to the maximum number of contributors."
Editor in Chief Bob Keating of the Open Directory Project, which is owned by AOL through their Netscape unit. They have what they call a "loose association" with Netscape's open source browser project, Mozilla. Directory Mozilla is the name referred to in their web address, dmoz.org. You can also get the link from our site, voanews.com/ourworld.
MUSIC: "Find a Way" by Kenny G
And you're listening to VOA's fully-categorized science and technology magazine, Our World. I'm Art Chimes in Washington.
If you've ever played computer games, here's something you might remember:
MUSIC: Super Mario Bros. theme
Video games have become a lot more sophisticated since Super Mario Brothers came out more than two decades ago. And while parents will probably always worry that their kids are spending too much time trying to "get to the next level," educators are starting to realize that computer games can provide an important platform for learning.
KELLY: "There's really no question that information is going to transform the way we acquire expertise and learn things. The real question is whether we're going to use it intelligently and effectively."
That's Henry Kelly, the president of the Federation of American Scientists, whose scientist-members focus on policy issues. They issued a new report this week urging greater use of video games to teach skills such as strategic thinking and problem solving, as well as the subjects that are today taught in classrooms using traditional methods.
Doug Lowenstein, head of the Entertainment Software Association, a trade group of video game publishers, says educational content will exploit the natural affinity of today's young people with computer games.
LOWENSTEIN: "By the year 2010, there will be 75 million Americans in this country between the ages of 10 and 30, the so-called millennial generation. Every single one of them will have grown up with video games as part of their lives. Games will be in their DNA just in the same way as television was in my DNA, or radio was in the DNA of my parents. We would be crazy not to seek ways to exploit interactive games to teach our children to enhance workplace training, to manage diseases, to train first responders, and so much more."
Some popular commercial games already have a significant educational value. Simulation games like Civilization, for example. But the Federation of American Scientists report urges the development of compelling games specifically for educational purposes. One example is Discover Babylon, where an engaging storyline helps kids ages 8 to 14 learn about ancient Mesopotamia.
DISCOVER BABYLON CLIP: "This catyclysm is no accident. Prof. Simon Dexter, we need you to help get him back before he does any more damage."
The game has commercial-quality look and feel, but also includes lots of solid content vetted by university and museum scholars.
Another example is Immune Attack, produced by the Federation of American Scientists to teach about immunology.
IMMUNE ATTACK CLIP: "I'm building a nanoprobe, a tiny, remote controlled robot, small enough for me to inject into my body."
Educational or not, there is some resistance to the use of video games in the classroom. U.S. school systems are heavily focused now on raising student scores on standardized tests. The focus on exams that mainly test students in reading and math has resulted in schools downplaying other subjects, such as languages. Don Blake of the National Education Association — a teachers' group — admitted that the introduction of unconventional teaching tools like video games could result in a short-term reduction in test scores, but he said long-term, it's worth it to better prepare youngsters for the future.
BLAKE: "This is going to prepare your kids for the 21st century. The scores on standardized test may be low, but the learning that they're going to have, that they're going to take into the workplace is going to be invaluable."
Don Blake of the National Education Association. One big obstacle to greater use of video games in school classrooms is the fragmented nature of the U.S. education system. Most decisions about curriculum, including which books or other materials to use, are made on the local level, in more than 15,000 individual school districts.
The latest effort by astronomers to find evidence of water on the moon has dampened hopes that there is much, if any, with which to establish a lunar colony. VOA's David McAlary reports on the latest research, published in the journal Nature.
McALARY: The moon appears barren and dry, but an early suggestion that it might have water came from a U.S. satellite mapping it in 1996. The satellite sent radar waves to a lunar south pole crater that is in permanent darkness. The return signal was characteristic of the way the waves would bounce off water molecules in ice.
Two years later in 1998, another U.S. satellite using different technology detected a component of water - hydrogen atoms - being displaced from the moon's surface by gamma ray bombardment from space. Researchers speculated that the hydrogen could be coming from ice deposits one-meter below crater floors at both lunar poles.
But a new study using a huge radar dish in Puerto Rico suggests that if there is any water on the moon, the amount is insignificant.
A team including Bruce Campbell of the Smithsonian Institution in Washington says the results imply that ice is likely to be present only as grains embedded in rock.
CAMPBELL: "People have suggested that if there were ice in thick slabs, then perhaps future lunar exploration would be made easier by going to those areas and using that as a resource. The results that we obtained are not very helpful for that. You probably would not want to use this small amount of ice spread through the dust as a resource."
McALARY: So if the Moon has no water, what was the source of hydrogen measured by the 1998 U.S. satellite mission?
A scientist who saw that data says the hydrogen could have been implanted by the solar wind, a powerful and continuous blast of electronically charged atomic particles from the sun.
Alan Binder, director of the Lunar Research Institute in Arizona, points out that future visitors to the moon could use this hydrogen to make water because there is also a lunar source for oxygen, the other component of water. Since both elements are rocket fuels, the moon could be used as a base to launch missions deeper into the solar system.
BINDER: "Rocks, lunar materials, have about 40- to 43-percent oxygen in them, so we have always planned on breaking the rocks down to get the metals and to get out the oxygen."
McALARY: Therefore, a lack of ice on the moon would not deter future lunar operations. But Binder notes that it is important to know what form the hydrogen takes before embarking on such ventures.
BINDER: "If we do not know what the form is and we go there thinking we are going to harvest ice with all kinds of ice harvesting equipment and it turns out to be solar wind implanted hydrogen, we have got the wrong equipment."
McALARY: Scientists say the only way to know for sure if ice lays beneath the moon's surface is to send a robotic explorer to dig down.
The U.S. space agency NASA plans to do this in 2008. It will dispatch a satellite to crash land on the moon to look for ice below the surface. In the same launch, it will send a second satellite that will orbit the moon to sense ice and other useful resources in addition to creating high-resolution surface maps and seeking landing sites for future missions. David McAlary, VOA News, Washington.
More than a century ago, English novelist H.G. Wells wrote about The Invisible Man. Ever since then, invisibility has been a staple of science fiction.
This week, invisibility moved from science fiction to science fact as a team at Duke University demonstrated the ability to make things disappear.
Well, sort of.
What they did is devise a way of steering one particular frequency of microwaves around an object so that, if your eyes were sensitive only to that microwave frequency instead of visible light, the object would seem to disappear.
Still, pretty cool.
In the 1990s, a physicist named Lawrence Krauss came out with a book called The Physics of Star Trek. In it he described how the alien race known as the Romulans made their spacecraft invisible by warping space so light rays bend around it. So I asked David Schurig, co-author of this week's invisibility paper, if that's what he and his colleagues have done.
SCHURIG: "Yes, functionally that's exactly what we're doing. The only difference is the Romulans are using some sort of space warp to do it, and we're using a material shell and the properties of that material being designed in a very specific way to bend the light rays around the object."
We see stuff because light reflects off it. By bending the rays, they don't reflect from the object, and there's nothing to see. To guide the microwave rays Schurig and his colleagues turned to a metamaterial.
SCHURIG: "Metamaterials are artificially structured composites that are a new way of tailoring the response - in our case, the electromagnetic response - of materials into areas that were not previously available."
The material of copper and fiberglass resembles printed circuit board with a geometric pattern tuned to a particular frequency.
SCHURIG: "So instead of relying on chemistry, we use artificial structuring and patterning to get the response we want, and it gives us a wider range of capabilities for the material.
Another member of the team, David Smith, said they are still a long way from the kind of invisibility imagined by science fiction writers.
SMITH: "When you think of cloaking or invisibility, you think of making something vanish. And usually you think of it optically vanishing, or you look at something and then it's gone. And right now we don't know how to do that. This is just a simple example where you can take one wavelength - for example, one color - and you could achieve cloaking of that color."
It may be a long time, if ever, before the science fiction kind of invisibility is achieved. In the meantime, the work that Smith, Schurig and their colleagues are doing at Duke University could find applications in communications, power-beaming, which is a technology for transmitting power through the air using microwaves or lasers — and, we have to also suspect, the military.
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That's our show for this week. If you'd like to get in touch, email us at firstname.lastname@example.org. Or use the postal address -
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Washington, DC 20237 USA.
Rob Sivak edits the program. Felicia Butler is the technical director this week. 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.