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This week on "Our World" ... A promising new study on stem cell therapy ... A search engine aimed at minority groups ... and how people with disabilities are finding new freedom in an online world ...

DUBIN: "It's not necessarily that they learn how to overcome. They are differently abled, and Second Life enables those differences to be functional."

Those stories, a first-hand report on global warming in the Arctic, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."


Scientists this week said they had apparently cured some laboratory animals with a fatal brain disorder after injecting them with human stem cells.

Dr. Steven Goldman of the University of Rochester led the research team. They developed new methods for processing the stem cells and for injecting them at several places in the brains of mice to maximize their effectiveness.

The mice used in the experiment were bred to have brains without myelin, which is a key part of the brain's electrical circuitry. Without myelin, these mice have seizures and die, typically within a few months. Because of their convulsions, they're known as shiverer mice.

The human stem cells used ? technically called "glial potential cells" ? spurred the growth of human myelin in the mice to replace the natural myelin they lacked.

GOLDMAN: "We can replace diseased cells in the brains of animals that have a defect that prevents them from making a critical substance in the brain called myelin, without which they die. But by virtue of replacing diseased cells with healthy cells, we can rescue the animals so that they live essentially normal life spans."

The mice that weren't treated developed seizures soon after birth, and they died within about 21 weeks.

For most of the mice in the group that got the stem cell transplant, the results weren't much better.

GOLDMAN: "Twenty of the 26 implanted mice died within a few weeks of when they would have been expected to otherwise. The shocker was that the animals that made it to that period, meaning out to about 24 weeks, then survived for good. And they improved day by day by day after that. They stopped seizing and they essentially were rescued."

Goldman says the key seems to be in keeping the animal alive long enough for the stem cell treatment to be effective.

GOLDMAN: "So we're looking at it as a critical time window where basically we have to speed up the myelination process a little bit, or as the case may be suppress seizures and prolong the survival of the overall population over that period of time where they're maximally vulnerable ? basically buy the animals enough time for the myelination to really kick in and take effect."

Steven Goldman says that in this study, they didn't make any effort to suppress the seizures, to give the mice a chance for the myelin to grow in their brains to overcome the seizures. He says they are running a similar study right now ? except that the animals are getting anticonvulsant drugs to give the stem cells treatment time to work.

Of course, the long-term goal of a study like this is the possibility of treating human disease. Goldman says he is optimistic that in the future this type of treatment might be helpful in treating a variety of myelin-related diseases, such as cerebral palsy and multiple sclerosis.

The study was published this week in the journal Cell Stem Cell.


Some of the most overlooked diseases around the world are parasitic infections, especially those caused by a kind of parasite called helminths. The group includes hookworms and schistosomes, among others. These worms, which live inside their host, are especially common in developing countries. As we hear from health reporter Rose Hoban, a new study found that if you're infected with one, you're probably infected with others, too.

HOBAN: Brown University researcher Amara Ezeamama was studying the frequency of individual parasitic diseases, when it occurred to her that many people are probably infected with more than one parasite at a time. So she set out to study how common a phenomenon that was. She studied several hundred children from villages in the Philippines.

EZEAMAMA: "In our data people were infected by two, three, four parasites over 93 percent of the time. You know, being free of infection or having only one infection happened only seven percent of the time in the entire study."

HOBAN: Ezeamama found this to be shocking, but after further study, realized that it was to be expected.

EZEAMAMA: "Most of these infections are soil-transmitted infections and they get contracted through a lot of hand to mouth activity. Or in the case of hookworm boring through the skin if you come in contact with infected soil."

HOBAN: Ezeamama says that parasitic infections are diseases of poverty. The millions, if not billions of people who have multiple parasites are constantly exposed to them in their environment.

EZEAMAMA: "The same risk factors that expose you to hookworm or the same things that expose you to schisto are the same life circumstances that force you to live in places that you have this infection. So there's a lot of co-linearity meaning that, if you contract one it's likely you've contracted another because they live in similar places, i.e., at some stage in their life cycle in the soil, and kids are walking around without shoes and a lot of things, it's not surprising to me just how people end up with a lot of them at once."

HOBAN: But what Ezeamama did find surprising was that being infected with one parasite made people more likely to be infected with another. And having more than one parasite elevated the risk of anemia in children.

EZEAMAMA: "It is likely that you will have anemia if you have any of these infections, even without the other. However when you have two of them together, the risk that you experience is not just hookworm plus Schisto, it's much more. It's about three times what you would have expected if those infections had independent effects."

HOBAN: Ezeamama says it's vital that health officials in poor countries systematically address both the parasitic infections and the conditions that lead to children being infected with different kinds of parasites at once.

Her reseach is published in the online journal PLoS Neglected Tropical Diseases. I'm Rose Hoban.


Veteran polar explorer Will Steger has just ended a two-month, 2200-kilometer dogsled expedition across Ellesmere Island in the Canadian Arctic.

Steger's international team set out to raise awareness of how global warming is affecting the Arctic.

Will Steger was a guest this week on VOA's Talk to America webchat. As you'll hear host Erin Brummett typing his comments for the Web, Steger described the tangible signs of climate change he observed while crossing the Arctic.

STEGER: "The big one was seeing the remnants of the Ayles ice shelf. This ice shelf broke off two years ago from northern Ellesmere Island and drifted down 450 kilometers, where we found it. We were traveling in this sea ice at that time that was only a year or two old. And looking at this Ayles ice shelf, this remnant that was so out of place ? to me it was like a flying saucer from outer space almost; it was an ice shelf that was like 7,000 years old. It was part of the last glaciation that was sitting there so out of place, caused by global warming. A real symptom, a real red light of the reality here of what we're doing to our atmosphere and our weather."

Will Steger on VOA's Talk to America webchat. You can read a transcript of the full conversation at their website,


Where did you go, say, on Tuesday? Same places as last Tuesday? The Tuesday before that? Well, researchers say a new study of mobile phone records shows people rarely stray from familiar areas. The findings could be useful to urban planners addressing problems as varied as traffic forecasting and emergency preparedness. VOA's Jessica Berman reports.

BERMAN: The study tracked the mobile phone use and movements of 100,000 people an undisclosed country.

Each time a call was made or received, or a text message recorded, investigators noted the location of the relay tower servicing the mobile phone.

Researchers found the calls were usually made to and from home and work within a five-kilometer area around the tower.

Marta González of Northeastern University in Boston, Massachusetts is the study's lead author. González says predictably, mobile phone users by and large stayed close to home.

GONZÁLEZ: "We really found that in fact 70 percent of the time, most of the people were found in two preferred locations."

BERMAN: González says less than one percent of cell phone users regularly ventured 500 kilometers from home.

González says mobile phone records provide an easy and readily available means of measuring the movement of populations, which she says could be useful to urban planners in a number of ways.

GONZÁLEZ: "When you have epidemics in a given place, you want to know which are going to be the most connected place according to the transport of people from one place to the other so you can take measures in advance."

BERMAN: With the number of mobile phones worldwide estimated to be three billion and growing, mobile phones have proved indispensable in coordinating rescue and relief efforts during natural disasters such as the recent Chinese earthquake.

The study on mobile phone usage is published in this week's issue of the journal Nature. Jessica Berman, VOA News, Washington.


Time again for our Website of the Week, when we showcase interesting and innovative online destinations.

As we move though this U.S. presidential election year, we are paying a little more attention to some of the political websites out there. But rather than looking ahead to the November election, this week we look back at more than two centuries of America's chief executives.

SUMMERS: " is a website about the presidents of the United States. It has information about each of them, while trying not to be too political. It's more educational."

Bob Summers is the creator of, spelled P-O-T-U-S, for Presidents Of The United States. At you can find an easy-to-navigate collection of basic facts about each president, plus extensive links to useful information on other sites.

SUMMERS: "Where they were born, their education. Then it starts to talk about the election, if there was one. Some presidents never were elected in their own right. Then their cabinet, links to biographies about them, other links to interesting speeches that they may have given, and other interesting little tidbits about the president."

Summers says his site gets visitors from all over the world, but it's a particular favorite of U.S. elementary school students, who no doubt like the basic facts and straightforward layout. But you don't have to be a kid to appreciate the easy access to Thomas Jefferson's Autobiography, or the results of each presidential election since 1789, or even the salary that each president got. (George Washington's, incidentally, was $25,000 a year, but he declined to take the money.)

To follow the 2008 election, has links to the latest campaign news and the candidates' websites.

SUMMERS: "I'm hoping to add a lot more information about the candidates, so that we can get a sense of who they are as people. One of the things I try to show is, these are real people, these are unique men. So I think that's where the future lies, learning more about these candidates as individuals."

U.S. presidential history since 1789 at, or get the link to this and more than 200 other Websites of the Week from our site,

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You're listening to VOA's science and technology magazine, Our World. I'm Art Chimes in Washington.


Internet search engines like Google are a popular way to your way around the online world. Because search engines often rank their search results, at least in part, based on a website's popularity, the results tend to reflect the majority culture. VOA's Adam Phillips reports on a new search engine geared to the interests of one of America's largest minority groups.

PHILLIPS: For people who live in a culture where most of their interests are shared by most others as a matter of course, it can be easy to overlook those who don't fit into their mold. That's why N'Gai Croal, technology editor for Newsweek magazine and an African-American, is only half jesting when he says that the results from search engines often reflect "the tyranny of the majority."

TAYLOR: "The majority of Americans on the Internet ? or a larger percentage of Americans on the Internet ? are white. And so a lot of the search terms you're going to get back are not necessarily going to be relevant for people who are black."

PHILLIPS: That's where can help. It's a new search engine targeted specifically at the growing number of African-American Internet users. RushmoreDrive developers took five years worth of search queries from, another search engine owned by the same parent company. Each of those millions of queries is linked to an Internet Protocol, or IP address indicating approximately where the computers making the search were physically located. Those results were then correlated with U.S. Census data indicating the neighborhoods with majority African-Americans populations. In this way, says Croal, RushmoreDrive could begin to rank search results in ways that were especially helpful to African-American users.

CROAL: "Say, when someone in Idaho was searching for the term "Whitney," they were maybe looking for the Whitney Museum [of American Art]. Whereas ? someone in Atlanta, which has a large black population, they might be looking for [pop singer] Whitney Houston."

PHILLIPS: RushmoreDrive.Com President and CEO Johnny Taylor is pleased with the feedback he's gotten since the website's launch early this year. Still, some critics balk at the idea of a race-based search engine. Isn't that "discrimination," they ask? Taylor's response: diversity is a cornerstone of the American marketplace.

TAYLOR: "That's why you, for example, have BET ? Black Entertainment Television ? and MTV ? Music Television ? which is really mainstream and focused on the majority community. There are all of these options. You have magazines, for example, that are targeted at women and magazines that are targeted at men. It's not that you're saying women can't read them. But ultimately, you're trying to give a group something that specifically speaks to them. And that's what we're about."

PHILLIPS: At the same time, black focus groups told RushmoreDrive developers that they weren't interested only in traditionally black products and services.

TAYLOR: "You wanted to not make an assumption, for example, when someone black types in 'restaurant' in a search box, that they are looking for soul food restaurants only. So we wanted to make sure we merged the best of all that the Web has to offer."

PHILLIPS: And Newsweek's N'Gai Croal adds that that this technology is not just for blacks. He says it might be useful to other interest groups.

CROAL: "You could do something that was aimed at people who are Chinese American. Or you can use it for people who are gay or lesbian.

There are any number of ways that you can drill down as long as you can find a way to geographically figure out with very little information? what it is that people are actually looking for when they type in a search term."

PHILLIPS: Research is already underway to customize the technology for use by those of African descent living in Canada and the United Kingdom. It's one more example of the powerful ways the World Wide Web is connecting individuals and groups with each other and with the estimated one and a half billion Internet users worldwide. I'm Adam Phillips reporting in New York.


Second Life is an Internet-based simulation of reality ? a virtual world with trees, buildings, animals and people. The "people" are animated characters guided by real-life people who can make their avatar look and act however they want. For someone with physical or emotional disabilities, this chance to "dream" through their online avatar can be a healing and empowering experience. Our Second Life correspondent Shelley Schlender reports:

SCHLENDER: Palm trees sway and the evening sky turns pink, as a woman with golden curls dances in a green party dress. Her name is Gentle Heron. A handsome man lifts her for a pirouette. Nearby, a man in a red T-shirt jumps into the air, and flies away. Another man turns into a dragon. Gentle Heron watches it all serenely.

ALICE: "I've got lots of friends in there. I've got friends from all over the world. Different kinds of people. It's really fun."

SCHLENDER: That's Alice Krueger, talking about how much she enjoys spending time in Second Life. Krueger, who has multiple sclerosis, says that living through her "avatar," Gentle Heron, is a refreshing change from her everyday life.

ALICE: "Here in this life I'm pretty much confined to my home; mostly I'm just in this room. And it's really nice to be able to go out and dance. I love to dance."

SCHLENDER: In real life, the flying man in the red T-shirt is Ron Sidell. Two years ago, a rare illness paralyzed him so completely, he had to breathe through a tube.

SIDELL: "I was trached [surgically fitted with a tracheal breathing tube] on a ventilator, and it was horrible."

SCHLENDER: While Sidell has regained some ability to move, he spends most of his time in a wheelchair. In Second Life, though, he gets to go everywhere, and dance.

SIDELL: "When I see my avatar dancing, the parts of my brain think movement. They sometimes feel what their avatar is doing."

SCHLENDER: That makes sense to Mark Dubin, a neuroscientist and former University of Colorado professor, who now designs virtual reality tools. He says the "real life" feel of Second Life occurs because this virtual world is different ? and much more ? than a video game.

DUBIN: "A fundamental difference is that you have an avatar. You have a representative that is you and responds to you. You move, it moves. You feel like you're there. Literally your brain will show activity typical of what the avatar is actually doing."

SCHLENDER: This makes Second Life a great place for learning virtually anything, even dog training.

VITOLO: "Here's what I want you to do. It'll be fun for you. Tell a dog, Yap."

SCHLENDER: Rossini, who has a brain injury due to a traffic accident, now teaches people ? and their avatars ? how to work with "virtual dogs" in Second Life. He puts special priority into training people with disabilities.

SCHLENDER: Thanks to these Second Life experiences, some people gain the confidence to own a real dog.

There are other skills that people learn, and that Krueger teaches, through Virtual Ability, an organization that highlights the benefits of virtual worlds for people with disabilities. Virtual Ability helps them learn how to get around in Second Life, which often makes a positive difference in their real life. Krueger recalls one woman who had difficulty with ordinary social relationships and was reluctant to have her avatar encounter other avatars.

KRUEGER: "So we had her working with plants because it was non-threatening to her. She became a landscaper, and our neighbors [in Second Life] saw that and hired her to do their [virtual] property."

SCHLENDER: Through these jobs in Second Life, the woman learned to make a budget, create a timeline and interact with people. With these skills, Krueger says, she got a real world job offer.

KRUEGER: "We were so excited. She was really excited too, because this was her first job. Ever."

SCHLENDER: Mark Dubin, the University of Colorado neuroscientist, says that people with disabilities often become isolated. He says Second Life can change that ... and be fun.

DUBIN: "Depression lifts. They become more excited and more interested. It's not necessarily that they learn how to overcome. To use the proper phrase, they are differently abled, and Second Life enables those differences to be functional."

SCHLENDER: Because Second Life can offer people so many friendships and teachable moments, Alice Krueger says that more than 70 English speaking groups assist people with disabilities or health issues through Second Life, and there are many support groups in other languages. For Our World, from inside Second Life, I'm Shelley Schlender.


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That's our show for this week. If you'd like to get in touch, email us at Or use the postal address ?

Our World
Voice of America
Washington, DC 20237 USA

Faith Lapidus edited the show. Eva Nenicka is the technical director. And this is Art Chimes, inviting you to join us online at or on your radio next Saturday and Sunday as we check out the latest in science and technology ... in Our World.