VOA标准英语2010年-Our World - 13 February 2010（在线收听）

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This week on Our World: Hopeful test results for a new malaria vaccine ... the debate over genetically modified foods continues ... and the promise and peril of looking for new medicines in the oceans.

BROOKE: "They are deliberately mowing down these deepwater coral ecosystems that are thousands and thousands of years old. And that's not going to come back - not in our lifetimes, not in many lifetimes."

Those stories, a physics lab in your computer, and more...

I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

Promising results reported in malaria vaccine trial

Malaria kills about a million people each year, mostly young children who haven't lived long enough to build up adequate immunity. A new vaccine addressing that deficiency has shown promise for protecting this most vulnerable population. Jim Hawk has the story:

HAWK: Around 300 million people get malaria each year through mosquito bites, but most recover and eventually build up natural immunity to the disease.

PLOWE: "Malaria, and especially the falciparum form of malaria that's most common in Africa, still kills almost a million people a year. Most of those are in Africa, and most of those are young children and babies who don't have immunity."

HAWK: Dr. Christopher Plowe is a professor at the University of Maryland's Center for Vaccine Development. He led an international team which developed a new malaria vaccine.

The parasite that causes malaria is spread through the bite of an infected mosquito. Currently, the best treatment is prevention - using insecticide-treated bed nets and mosquito eradication campaigns.

While there are medications to fight the disease, the malaria parasite is becoming resistant to many of the available drugs. The new vaccine contains a protein from the malaria parasite plus a booster compound called an adjuvant. It targets the parasite as it starts to multiply in the blood.

PLOWE: "This is a blood stage vaccine that prevents the parasites from invading the human red blood cells - that's the part of malaria that makes people very sick."

Other vaccines that attack this stage of the parasite have been tested, but this is the first one found to work effectively. Although based on a single strain of malaria, there's hope this new vaccine can protect against the half-dozen malaria parasites known to exist.

The first phase of testing has just been completed in West Africa, by researchers at the University of Bamako in Mali. They vaccinated 100 children, and found the drug stimulated strong and long-lasting immune responses, as measured by the presence of antibodies in their blood.

HAWK: Plowe says a larger follow-up study with 400 children in Mali has just ended, although the results have yet to be compiled. If the vaccine is as effective as researchers hope, the final stage of clinical trials can then be planned. The study is published in the online version of PLoS One, a journal of the Public Library of Science. I'm Jim Hawk.

Children seen to benefit from medical journal's reversal on vaccine-autism link

Earlier this month, a prestigious medical journal disavowed an article it published more than a decade ago that linked autism in children to a common childhood vaccine. The original article raised widespread concern about the safety of the vaccine, prompting many parents worldwide to stop vaccinating their children. As VOA's Jessica Berman reports, vaccine proponents hope the retraction will eliminate doubts about the safety of the vaccines.

BERMAN: In 1998, a high-profile article published in the British medical journal, The Lancet, announced a link between autism and the MMR vaccine, used against measles, mumps, and rubella.

There had been no established cause shown for autism, a disorder that affects a youngster's social skills and ability to interact with the outside world.

In the original paper, British gastroenterologist Andrew Wakefield described a small sample of 12 children, eight of whom showed evidence of autism shortly after receiving the vaccine.

However, subsequent investigations by British regulators led to charges that Dr. Wakefield falsified data and was paid by the parents of autistic children.

In 2004, as scrutiny and criticism of the study intensified, ten of 13 co-authors of the 1998 autism article publicly disassociated themselves from from it.

A telephone call made to Wakefield asking him to comment on the Lancet retraction was not returned.

Over the past decade, as the vaccine-autism link gained traction among some groups, the scientific community has been unable to confirm the connection.

Paul Offit, a vaccine researcher at Children's Hospital in Philadelphia, says at least 12 studies have been done worldwide concluding repeatedly that the MMR vaccine does not cause autism.

OFFIT: "We've reached the many hundreds of thousands mark of children who did or didn't receive MMR to see whether risk of autism was greater in the vaccinated group and it wasn't; consistently, reproducibly, redundantly. I think that the problem is not that the science hasn't been done; the problem is there are people who simply don't believe the science."

BERMAN: Offit says a number of other studies have been done searching for a biological cause for autism.

OFFIT: "There are some very interesting studies. It's all very interesting. You never hear about it because I think that the anti-vaccine forces have taken this story hostage, much to the detriment of children with autism."

BERMAN: Numerous vaccination opponents contacted for this report either didn't return telephone calls or declined to be interviewed.

Since the Wakefield paper, experts say there's been a rise in the number of measles cases worldwide.

University Of Texas psychologist Katherine Loveland, who specializes in autism, thinks the retraction by The Lancet will reassure parents of small children.

LOVELAND: "I would definitely vaccinate my child. And the reason is I know that the risk from getting those childhood diseases, which we tend to forget can be killers, the risk of them is so much higher than any hypothetical risk of an increased chance of getting autism."

BERMAN: Vaccination proponents say they are hopeful that The Lancet's retraction of the 1998 autism article will, at the very least, help restore public confidence in the safety of the measles, mumps and rubella vaccine.

Jessica Berman, VOA News, Washington

Controversy over genetically modified foods boils over after India bars GM eggplant

On last week's show we reported on a new genetically modified, or GM, vegetable, an eggplant engineered to produce its own insecticide, to improve yields and reduce the need for chemical spraying.

But this week, officials in India - a country that was expected to be a big market for the modified eggplant - refused to allow commercial planting of the vegetable until more tests are done to demonstrate its safety.

It's the latest example of the ongoing debate about the risks and benefits of crops which have been geneticaly modified to tackle some of the world's biggest challenges in agriculture, from drought and floods to pests and disease. VOA's Steve Baragona reports.

BARAGONA: Supporters say the GM eggplant would improve yields and reduce the use of harmful pesticides. Opponents say they are a threat to human health and environmental safety.

These are the same battle lines that were drawn even before the first GM crops were introduced in the 1990s. And they haven't changed much since then.

That's despite the fact that for the past 13 years, GM crops have been grown and consumed without any evidence of a major health or environmental problem. An estimated 100 million hectares of GM crops were grown in 25 countries in 2008. That should put the opposition to rest, says Nina Fedoroff, a plant geneticist and a U.S. State Department advisor. But it hasn't.

FEDOROFF: "The only way that I can stay patient is to recognize that this is not unique to GM foods, and it is not new."

BARAGONA: Fedoroff says one reason that hostility to GM foods persists is because scientific advances often move faster than public acceptance. In the 19th century, opposition to a new smallpox vaccine continued after scientists were convinced it was safe and effective.

Fedoroff and a group of scientists from U.S. universities, international institutes, and seed companies write in this week's issue of the journal Science, quote, "There is a critical need to get beyond popular biases against the use of agricultural biotechnology." The article notes that there will be 3 billion more mouths to feed by mid-century while climate change threatens food supplies. GM, they say, is one of the technologies that can help meet the challenges.

BARAGONA: But the urgency supporters feel to move GM technology forward is matched by the intensity with which the opponents say, "slow down."

Mira Shiva, with the Indian group Doctors for Food and Biosafety, is one of them. She says, look at the experience with some pharmaceuticals.

SHIVA: "Numerous drugs that were said to be very safe, over time they were found not to be safe. It happens. But they could be withdrawn. You cannot withdraw genetically modified [crops] at all. You cannot withdraw [them]. So, god forbid [that] tomorrow there are problems."

BARAGONA: Doug Gurion-Sherman used to look for problems with GM crops as a regulator with the U.S. Environmental Protection Agency. He's now with the Union of Concerned Scientists. And he says one reason the doubts about GM crops persist is because even after more than a decade of use, some questions have gone unanswered.

Gurion-Sherman says the data requirements for toxicity, for example, only call for 90-day tests, and they are not sensitive enough to detect problems if they do arise.

GURIAN-SHERMAN: "Until the proponents of the crop, who have adamantly resisted strengthening regulations, understand that public confidence is going to depend on regulatory agencies that can be counted on, that huge public mistrust is going to remain."

BARAGONA: And this question of trust will come up again and again. New GM crops are being developed that promise to cope with some of the world's biggest challenges in food production: tolerance to drought and salty soils, and more efficient use of fertilizer, for example. But, as India's moratorium on GM eggplant shows, these innovations will likely remain on the shelf unless the public trusts the regulators who say these crops are safe.

Google plans test of super-speed Internet service

Google, the giant Internet search and advertising company, has been extending its brand lately.

Last month they introduced their smart mobile phone, Nexus One. And this week, Google said it would begin a limited roll-out of ultra-high-speed Internet service in the U.S., providing customers with connections that can move one gigabit of data per second. That's about 100 times faster than the typical broadband connection users here now enjoy.

Google said in a blog posting that the service would be available to 50,000 customers at first, with as many as a half-million more eventually receiving the service at what company spokesmen called "competitive" rates.

They said a web connection this fast would allow users to download the digital file of a high-definition, two-hour-long feature film in five minutes, or allow doctors at a rural health clinic to stream very large 3-D medical images to a specialist in a distant city.

The company calls this an experiment. It's unclear whether Google plans to compete against established internet service providers.

Website features interactive science experiments

You won't need a one-gig internet connection to check out our Website of the Week.

This time it's an educational site where principles of physics are illustrated with interactive animated experiments that you can perform on your own computer.

PERKINS: "The PhET website is a collection of 85 simulations for teaching and learning science. So our main goal is to help students better understand the science of the world around them, but instead of telling students how something works, our simulations let them discover important science concepts for themselves and really learn and engage through scientist-like exploration."

Kathy Perkins is co-director of the Physics Education Technology, or PhET Interactive Simulations website, at phet.colorado.edu.

Despite the name, the site also includes animated simulations in biology, chemistry, and other disciplines, as well as physics. You can build your own solar system, model the hydrogen atom, or explore the properties of a gas as you change its temperature and other variables.

Another simulation allows you to design and modify a simple electrical circuit.

PERKINS: "So when you open up, you can drag out wires and batteries and bulbs. And as you connect them, as soon as you complete a circuit, you'll see the light bulb light up and the electrons shown in the wires circulate around the circuit."

The simulations look like entertainment, but Perkins says the design of each has been tested for its educational value and can be used in the classroom, or you can just run the sims yourself and learn by doing online at phet.colorado.edu, or get the link from our site, VOAnews.com.

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

 Does non-verbal communication translate across cultures?

When we communicate, we don't just use words. Non-verbal communication is important, too. If you're talking face-to-face, things like facial expression, eye contact, and how close you stand can be an important part of the message.

There's also what researchers call "non-verbal vocalizations" - sounds that send a message without using words.

But how universal are these messages?

That's what Disa Sauter wanted to find out.

SAUTER: "And we were specifically interested in emotional expressions in the voice - so things like laughter, crying, sighing, grunting - those kinds of noises that we all make, but what do they actually mean?"

What do they mean and, more specifically, do they mean the same things to people in different cultures?

SAUTER: "So to look at that, we studied a group called the Himba, who are a culturally isolated group, so a group that doesn't really have anything to do with other groups. And they live in the north of Namibia in Southwest Africa."

The Himba participants in the study live a life that is about as isolated as you can be in the modern world. The other group in the study included native English speakers in Europe.

People in both groups were asked to make sounds that expressed emotions like joy or anger without using words.

So for example, they were told to make a sound like they just realized they had eaten some rotten food.

Researchers recorded the sounds, then played them for people in the other groups to see, for example, if the Himba recognized the sound of disgust that the Europeans made, and vice versa. Listen, first, to how a Himba expresses disgust, then how it sounds when a European does it.

[sounds of disgust made by Himba, English]

They sound a lot alike, which may be why both groups recognized the sound registering disgust.

Sauter found that the sounds conveying negative emotions could be understood across cultural boundaries more readily than the sounds of positive emotions. She says that could be because negative emotions might be older, in our evolutionary history.

SAUTER: "And that could mean in a sense that they are more important. So we need fear to be able to react appropriately do a dangerous situation, to run away; and also it's important in a situation of threat to warn those around us - who are likely family members and close friends - to warn them of the danger that we're facing."

Positive emotions tended to sound more different, like this ones signifying achievement expressed by an English speaker and a Himba.

Sounding that different, it's not surprising that each group had a hard time identifying that and other sounds representing positive emotions. Sauter says it may be because positive emotions are more about creating and strengthening bonds within one's own group, so you might not want others to know about it.

SAUTER: "The exception to this is laughter, which seems to be something that we're prepared to share with strangers and friends alike, which I think is fairly reassuring, actually, that there are positive emotional signals that can communicate across all cultural boundaries."

We reached Disa Sauter at her current office at the Max Planck Institute in the Netherlands. She was at University College London when she did her research, which was published online by the Proceedings of the National Academy of Sciences, which also gave us permission to use the audio clips used in the study.

 Prospecting the oceans for new medicines

Making medicine from things found in nature isn't a new idea. Aspirin, for example, originally came from the bark of willow trees. Now drugs derived from ocean animals are slowly making their way onto pharmacy shelves.

Reporter Samara Freemark checked in with one researcher who is prospecting in the sea for a potential medical breakthrough.

FREEMARK: Marc Slattery is trying to find a cure for cancer. Slattery is a pharmacology professor at the University of Mississippi. But he doesn't really spend much time in the lab. Instead, he's usually in a wetsuit, scuba diving off the coasts of places like Guam and Antarctica.

He's taking samples from tens of thousands of corals and sponges. He's looking for that one special species that might make a chemical that could cure disease. He calls it, 'diving for cures.'

SLATTERY: "In many ways, it's like going out and playing your super lotto or whatever. You pick your eight numbers and you see if you hit or not."

FREEMARK: The idea is pretty simple. A third of the medicines on shelves today were derived from plants and animals that live on land. So ocean researchers got to thinking that the organisms they studied probably also produced a lot of useful chemicals.

Take corals and sponges. They can't run away from predators, so instead they squirt out chemicals that poison the fish that try to take a bite out of them. Marc Slattery says those toxins are bad for the fish - but they could be good for people.

SLATTERY: "Those particular compounds that tell a fish 'not today' are the same ones that might tell the AIDS virus 'you can't replicate' or tell a cancer cell 'you're dead' or those kinds of things."

FREEMARK: So Slattery and other researchers like him clip off bits of sponges and corals. When they get back to the lab they extract the chemicals.

Once they've extracted the chemicals, researchers test to see if they have any human application. If a compound looks promising, it moves on to clinical trials. Those trials can take decades, which is why ocean-derived drugs are only now starting to hit the market.

I wondered how ocean conservationists felt about diving for cures. So I called up Sandra Brooke. She studies corals at the Marine Conservation Biology Institute. Brooke says she does worry that diving for cures could lead to over-harvesting.

BROOKE: "Once something becomes valuable to people, there's a resistance to closing access to it. It becomes harder to regulate it."

FREEMARK: But she says corals are under much greater and much more immediate threats. The biggest culprit is industrial trawling. That's when fishermen scrape reefs off the ocean floor so they can get to the fish.

BROOKE: "It's just like the clear cutting of the forest, except it's one on a much vaster scale. They are deliberately mowing down these deepwater coral ecosystems that are thousands and thousands of years old - some of the oldest animals ever measured. And that's not going to come back - not in our lifetimes, not in many lifetimes."

FREEMARK: There's also the fact that oceans are changing as the climate does. Those changes mean corals are becoming weaker. Marc Slattery thinks he might be seeing that in a Pacific reef he's been studying for fifteen years.

SLATTERY: "When we went back and started looking at it, we noticed that there was a change in the chemistry through time. As things have heated up on the reefs, there's a physiological effect that has cascaded down into their ability to produce the chemistry we're used to seeing. Early on it was so apparent, it was always there, and now they seem to be able to produce less of it."

FREEMARK: That's means that today the cure for cancer might be out there in some coral reef, but it could be gone tomorrow.

For The Environment Report, I'm Samara Freemark.

Support for the Environment Report comes from the Joyce Foundation, and the Great Lakes Fishery Trust. You can hear more stories and subscribe to the daily podcast at EnvironmentReport.org.

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