源 稿 窗
31 July 2009
MUSIC: "Our World" theme
This week on Our World: The high cost of obesity and what we can do about it ... how carbon dioxide in the air is making the ocean more acidic ... and setting a goal for the next step in human spaceflight ...
ZUBRIN: "We're much better prepared today for humans to Mars than they were to be able to send men to the Moon in 1961, and they were there eight years later."
Those stories, a network of instruments that could provide life-saving earthquake warnings, and more.
I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
Study estimates cost of US obesity at $140 billion
Americans are known for a lot of things around the world, but love us or hate us, you probably think we weigh too much.
And we do.
Two-thirds of adults in the United States, and one out of five children, are above what doctors consider a healthy weight for their size, and those numbers have been increasing. And people who are above their healthy weight are, not surprisingly, not as healthy.
It's no wonder experts talk about an "epidemic" of obesity.
FRIEDEN: "Obesity and with it, diabetes, are the only major health problems that are getting worse in this country, and they're getting worse rapidly."
Dr. Thomas Frieden, head of the U.S. Centers for Disease Control and Prevention - the CDC - says the rate of obesity has doubled over the past generation.
A new study published this week puts a dollar estimate on that epidemic of obesity - $140 billion a year in extra medical costs.
Obese people spend, on average, $1,500 per year more for their medical care than a person of healthy weight.
And of course, says Frieden, the financial burden is only part of the story.
FRIEDEN: "Beyond the economic costs are the disability, the suffering and the early deaths caused by obesity. And this is something that we as a society need to take more action to address."
We should explain our terms here. Obesity is defined based on a body mass index of 30 or higher. For example, if you weigh 100 kilograms and your height is 180 centimeters, your BMI is 31, which is considered obese. A separate category - overweight - applies to people who are above what is considered a healthy BMI, but not so much that it's classified as obese.
The new study on the costs of obesity is published online by the journal Health Affairs. Lead author Erik Finkelstein says those costs have nearly doubled over the past decade. About half of those costs are paid for by government programs like Medicare, which insures older Americans.
FINKELSTEIN: "Their average expenditures are about $4,700 [per year] if they're normal weight, and if they're obese that number rises to about $6,400."
Finkelstein is affiliated with RTI International, a North Carolina research institute.
He says obese, older Americans are more likely to have chronic disease requiring medication, which drives up their medical costs.
He discussed his study in Washington this week at the CDC's first ever national conference on obesity control and prevention.
A report published in a CDC publication outlines a variety of ways to head off the spiraling obesity epidemic. William Dietz, head of CDC's obesity unit, says there are a number of strategies to get the weight off, or keep people from gaining weight in the first place.
DIETZ: "Strategies to support choices of healthy food and beverages, strategies to encourage breastfeeding, strategies to encourage physical activity or to limit sedentary behavior, or strategies to create communities that support physical activity."
Some of the recommendations include smaller portion sizes in restaurants, discouraging beverages sweetened with sugar, increased physical activities in school, improved access to walking and mass transit.
Eric Finkelstein, the researcher who quantified the financial costs, says we have to do something.
FINKELSTEIN: "So many differentials are involved that the only thing we do know is that in the absence of action, it's unlikely that costs associated with obesity are going to decrease."
One approach could be taxing some unhealthy foods, which would raise prices and maybe encourage people to make healthier eating choices. CDC Director Thomas Frieden cites the success of higher taxes in reducing smoking by half among teenagers in New York.
FRIEDEN: "In the case of soda and other sugar-sweetened beverages, evidence from a couple of sources, including industry sources, suggests that higher prices will strongly discourage people from consuming soda and other sugar-sweetened beverages."
Still, it's likely to be an uphill battle, changing the habits of millions of people who would rather watch TV while eating fattening food than exercise or reduce the fat and calories in their diet.
If you want to eat healthier, stay tuned. Our Website of the Week can help. Coming up later in the show, but first ...
Study indicates how to keep newborns safe from HIV
One of the most tragic aspects of the AIDS epidemic is transmission of the disease from mother to child. In low-income countries, hundreds of thousands of babies have had the virus passed to them by their mothers - either during birth or while they are breastfeeding. But some new research should bring hope to mothers with HIV. Rose Hoban reports.
HOBAN: Doctors have known for a decade that giving the anti-retroviral AZT to HIV-positive women during labor greatly reduces the chance they will pass their disease on to their babies. But health authorities in Africa estimate that hundreds of thousands of children still contract HIV after birth, says Charles van der Horst, an AIDS researcher from the University of North Carolina.
VAN DER HORST: "We know that there are 420,000 babies infected each year with HIV. So it's devastating. Pediatric HIV is a medical emergency. Half of these babies will be dead within a year."
HOBAN: Van der Horst says formula isn't a good option for treating these babies, either because of cost, unavailability or the risk of a bout of diarrhea, which can be fatal. So, van der Horst and colleagues studied the effect of anti-retroviral drugs on breastfeeding women and babies in the African nation of Malawi.
In one arm of the study, they gave women a widely used regimen of three anti-retroviral drugs for 28 weeks of breastfeeding after birth. Another group of women got an infant formulation of the anti-retroviral nevirapine to give their babies daily for the 28 weeks. A third group of women and babies were the control. They got the standard of care - that is AZT during labor and seven days of nevirapine after birth for the babies. Van der Horst says the results were dramatic.
VAN DER HORST: "We found that in particular the baby getting the single daily dose of nevirapine had a dramatic decrease in the number of babies who were infected. And that decreased from, in the standard of care arm, from 6.4 percent of the babies becoming an infected down to 1.8 percent being infected. And it was 3 percent of the babies whose mothers were getting the medication became infected."
HOBAN: One concern raised in the study is that women receiving antiretroviral drugs have to be monitored using expensive lab tests?? and that can be difficult. Van der Horst says giving infants a daily dose of nevirapine is his preferred option.
VAN DER HORST: "It's very, very cheap, it's virtually non-toxic and you don't need to do any monitoring lab tests, you don't need a laboratory to monitor the babies wears a mother who is getting three drugs to treat her does it need to be monitored for anemia and other medication side effects."
HOBAN: One problem with this treatment strategy, says van der Horst, is that babies are susceptible to diarrheal diseases once they are weaned at 28 weeks. He believes babies should not be weaned and should continue on the medication beyond the 28 weeks. van der Horst is planning to study this mode of treatment next.
I'm Rose Hoban.
Oceans becoming more acidic, endangering sea life
Rising levels of carbon dioxide in the atmosphere are a major contributor to climate change, and now a new study has confirmed that atmospheric CO2 is also affecting the ocean chemistry, potentially threatening marine life.
Montana State University scientist Robert Dore has been taking samples of water in the Pacific Ocean for almost two decades.
DORE: "We're sailing out of Honolulu harbor. We're in the harbor right now and just about to break away from the dock."
I reached him on board the research vessel Kilo Moana, about to leave for a point in the Pacific known as Station Aloha, where he has been studying the ocean water since the late 1980s.
DORE: "We've been going to the same spot in the Pacific Ocean. And one of the key things that we measure is CO2 levels. And we've been able to document this progressive invasion of atmospheric CO2 into the ocean."
As CO2 gets into the ocean, scientists have expected it to affect water chemistry there.
DORE: "As carbon dioxide dissolves in water, or seawater in this case, it forms a weak acid, carbonic acid. And therefore, as the concentration of CO2 in the atmosphere goes up and that exchanges with the surface seawater, it drives the pH down, makes it more acidic."
The samples Dore and his colleagues have analyzed confirm what the theory predicts.
DORE: "The pH of the ocean out here has been decreasing. And it has been decreasing at pretty much the rate that we'd expect from the physics and the chemistry."
The lower pH levels - measuring increased acidification - varied seasonally and also from year to year. And it varied with depth.
Dore's laboratory measurements are not just equations and charts in his paper. He says they have a real-world impact.
DORE: "It's important to realize that acidification of the oceans is really happening. And it can have negative impacts on a whole variety of marine life from fisheries to coral reefs. It's potentially catastrophic."
Montana State University environmental scientist John Dore's paper appears this week in the Proceedings of the National Academy of Sciences.
Website of the Week offers healthy eating advice
As we heard earlier, obesity is costing Americans a lot of money.
Eating healthy isn't always easy, and sometimes we may not know the best choices to make. Our Website of the Week features nutrition advice from a respected source.
CHEUNG: "The Nutrition Source is a website that helps people cut through nutrition confusion. We provide clear and actionable advice for healthy eating that people can use for their daily meals, and at the same time we try to dispel some nutrition myths along the way."
Lilian Cheung is editorial director of TheNutritionSource.org, a project of the Harvard University School of Public Health.
The site features nutrition news, advice on reaching and maintaining a healthy weight, and recommendations for eating right.
CHEUNG: "Focus on whole grains. Pay attention to your protein packages. Choose healthy fats; avoid trans-fats. Eat lots of vegetables and eat whole fruits. So as you can see, there is a section that gives anyone from any part of the world information that they can use and adapt."
The Nutrition Source also features a recipe library, healthy dishes for your family - even institutional-size recipes if you happen to be cooking for 100 guests.
Eating advise you can trust from TheNutritionSource.org, or get the link to this and more than 250 other Websites of the Week from our site, VOAnews.com/ourworld.
MUSIC: Cab Calloway - "Everybody Eats When They Come To My House"
You're listening to Our World, the low-fat weekly science and technology magazine from VOA News. I'm Art Chimes in Washington.
Nationwide sensor grid may provide earthquake warning
Earthquakes are one of nature's most destructive forces. You know that if you saw the devastation in Italy in April or in China's Sichuan Province last year. Scientists are trying to improve their understanding of earthquakes and the forces that power them beneath the Earth's surface. As we hear from reporter Erika Celeste, a National Science Foundation program called EarthScope is trying to enhance our understanding of earthquake science, and bring the excitement of research into classrooms and museums.
CELESTE: The earth is always in motion. And those groans, moans, and cracks are the movements of the earth. Just as our planet spins in a never-ending journey around the sun, its mantle plates deep underground are constantly moving and shifting. But much of it happens so slowly - just 5 to 7 centimeters a year - that the sound has to be sped up and amplified so that it can easily be heard by the human ear.
Sometimes, though, the earth moves a lot faster.
GAO: "We still don't know why there are earthquakes."
CELESTE: Seismologist Stephen Gao has worked in Africa, China, and Siberia. He is currently heading a research team for EarthScope, a project which is seismographically mapping the continental U.S. and Alaska.
GAO: "This is part of a huge project. The idea is to use 400 seismographs to cover the whole U.S. in about 14 years. We are to start from the western coast and move all the way to the eastern coast."
CELESTE: The project is currently entering the area of the New Madrid fault zone, in Missouri and several nearby states. It's the site of one of the most powerful earthquakes ever recorded in North America.
GAO: "The key is not to prevent but to predict, but you can predict one and then you can do something to lessen the damage caused by an earthquake. People can come out of their house. You can shut down the power, the natural gas lines. You can reduce the damage a lot."
CELESTE: The placement of those 400 seismometers is critical. Because the instruments are highly sensitive, they can't be too close to roadways or large trees. Both give off vibrations that could create false readings. So, here in Missouri, open cow pastures and hay fields are the best locations.
Gao has enlisted the help of four students to identify possible seismometers sites. Today, senior geology major Alicia Metzger from Missouri State University and graduate student Ben Williams of Missouri University of Science and Technology, where Gao teaches, are double-checking one of their candidate sites to make sure it's still suitable. On the way, they explain how the project's sensitive instruments work.
METZGER: They measure any sort of vibrations underneath. And then they also perform sort of what they describe as like a CAT scan, so that way we get an idea of what the mantle and the bedrock looks like.
WILLIAMS: She mentioned the CAT scan and that's why they have the grid of these seismometers. Because rather than seeing what's going on under the ground at a specific point, they can pool the resources from all of these seismometers and that's what's able to give them more of a visual picture of what's going on. Rather than having just one point and seeing what's going on there, you have 20 points per state seeing what's going on at all times.
CELESTE: A short drive later, the students arrive at Kirby Farms, a scenic cattle ranch off the beaten path, with rolling hills and bright green meadows.
Workers will soon build a small underground station at Kirby Farms by digging a deep hole and reinforcing it with concrete. Then a network of sensitive equipment, wires, and meters will be installed to monitor the earth's activities. Through the use of cellular telephone and satellite signals, the station will transmit data for the next two years.
METZGER: "So the information we're going to get will advance many fields of science."
CELESTE: Gao says one of the important things about this study, is that scientists don't have to wait until it's finished to begin analyzing the data. EarthScope makes it available to everyone via the internet through live streaming.
GAO: "People are already starting to publish things. So actually the papers are already being published and on the way. You don't have to wait for the end."
CELESTE: As researchers learn more, the information will be used to help educate the public about earthquake science and safety. And scientists and engineers hope to use what they learn from EarthScope to design stronger earthquake-resistant structures, and improve earthquake and volcano predictions.
For Our World, I'm Erika Celeste in Rolla, Missouri.
Enthusiasts say Mars should drive spaceflight program
NASA's Human Space Flight Plans Committee has been holding a series of public meetings to review the direction of the American space program in the post-Shuttle era. The committee will meet in Washington on Wednesday, chaired by former aerospace industry executive Norman Augustine. One of the people they'll be hearing from is Robert Zubrin, head of the Mars Society, which promotes sending astronauts to explore and live on the Red Planet. I asked Zubrin what he plans to tell the NASA panel.
ZUBRIN: The Augustine committee has been set up to reexamine the situation and the proper future goals of the American human spaceflight program: Should we go back to the Moon? Should we make Mars our goal? Should we retreat from all this sort of thing. You know, my testimony to the committee is going to be very straightforward and forceful. It's going to be that the American human spaceflight program absolutely needs a driving goal, and that goal needs to be humans to Mars.
Q: We've gotten some wonderful return from Mars Rovers, robotic missions. What does human spaceflight to Mars deliver that these machines can't?
ZUBLIN: Well, in the way of exploration, a human's vastly superior to a robot. We've actually, in our practice Mars space up on Devon Island in the Arctic, we've compared the effectiveness of humans to robots, and literally humans are 1,000 times (better) - and I mean that. Anything a robot can do, a human can do in one one-thousandth the speed. And there's innumerable things that humans can do that robots just can't do at all. And then if you talk about looking for live organisms, setting up drilling rigs and drilling down to the groundwater and taking it up and taking it to the lab and culturing it and looking at it with microscopes - these things are all far beyond the ability of robotic rovers. If we want to know the truth about whether there is or ever was life on Mars, we're going to have to send people.
Q: Do we have the technology to send people to Mars, or is this something that needs to be developed?
ZUBLIN: Well, we don't have the various hardware elements that are needed, but in terms of the general level of technology, we absolutely do. We're much better prepared today for humans to Mars than they were to be able to send men to the Moon in 1961, and they were there eight years later. If President Obama was to get up this summer and commit the nation to sending humans to Mars, we could be there by the end of his second term [in 2017].
Q: Do you have a sense of whether the Obama administration, given particularly the eocnomic situation now, presents a political climate that might be friendly to a Mars mission?
ZUBRIN: There's always other things going on. There was plenty of other things going on when Kennedy committed us to go to the Moon in 1961. There's a lot of justification for embracing the goal of humans to Mars, in particular in the current situation. A humans to Mars program would be a tremendous driver for our economy, as Apollo was to the U.S. economy in the 1960s. You know, we were in recession in '61-62, and the Apollo program drove us right out of it into five, six percent rates of economic growth for most of the decade. It will also be a massive boost for education, science education. The Apollo program doubled the number of science graduates in this country in the 1960s at every level - high school, college, PhD. Se we get millions of scientists, engineers, inventors, doctors, medical researchers, technological entrepreneurs. These are the people who advance our economy. These are the people who solve all the kinds of problems that we face.
Look, the American space program, the human spaceflight program in particular, has been on idle since 1973. We haven't gone anywhere new in 36 years. And here we are celebrating the 40th anniversary of the Apollo 11 moon landing. We should be celebrating the 20th anniversary of the first Mars landing. But we're not. So we got to get this thing moving again, and the proper goal for this day and age is Mars.
Robert Zubrin heads the Mars Society. The group is holding its annual convention this weekend just outside Washington.
MUSIC: "Our World" theme
That's our show for this week.
If you'd like to get in touch with us - maybe you've got a science question we can answer for you on the show - our email address is firstname.lastname@example.org. Or use the postal address -
Voice of America
Washington, DC 20237 USA
Our World is edited by Rob Sivak. 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.