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Our World — 25 August 2007

MUSIC: "Our World" theme

Straight ahead on "Our World" ... the space shuttle returns safely to Earth ... a virus is implicated in obesity ... and seed banks help protect tomorrow's food supply.

FORSLINE: "If it's lost, it's lost forever. You can't recreate germplasm. It's a legacy and a resource for all of mankind for all of the future."

Those stories, the challenging search for an AIDS vaccine, and, oh yeah, sex and older Americans. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

The space shuttle Endeavour landed without incident on Tuesday despite a damaged heat shield on its underbelly. The shuttle glided to Earth at the Kennedy Space Center in Florida where it began its journey 13 days earlier.

SHUTTLE: "Houston. Endeavour. Wheels stop.
HOUSTON: "Roger. Wheels stop, Endeavour. Congratulations, welcome home. You've given a new meaning to higher education."

That's a reference to astronaut-educator Barbara Morgan, one of the seven crew members on Endeavour. The shuttle delivered three tons of supplies to the International Space Station, where they performed four space walks as they continued construction of the orbiting outpost.

Early in the shuttle mission a small gash was discovered in a couple of the ceramic tiles that protect the ship's underside from the extreme heat of re-entry. NASA specialists spent days considering whether to risk a spacewalk to fix the damage, but in the end decided it was safe for the shuttle to return without a repair.

The damage was caused by a piece of insulating foam that fell off the shuttle's external fuel tank during launch. Four and a half years ago the shuttle Columbia burned up during re-entry after it, too, was hit by a piece of foam at launch.

Of 119 space shuttle flights, two have ended in catastrophe. In addition to Columbia, the shuttle Challenger exploded seconds after liftoff in 1986. In both cases, all seven astronauts on board were killed.

Before Tuesday's successful landing of Endeavour, shuttle program manager Wayne Hale reminded reporters at a news conference that sending humans into space is inherently dangerous.

HALE: "What we are doing by launching people into space isn't remotely safe by any normal human measure. This is a risky business. We're doing it because the rewards for our country — and in fact, we believe, for all of humanity — are worth that risk. But it is a risky proposition.

Some critics of human spaceflight say that robotic space probes can be more productive and don't needlessly endanger human life. They point to the success, for example, of Spirit and Opportunity, the two little rovers on Mars, and the granddaddies of all space probes, the two Voyager spacecraft.

Last Monday was the 30th anniversary of the launch of the first of the twin Voyager spacecraft. The other was launched a couple of weeks later. Over the next 12 years the two probes swung past Jupiter, Saturn, Uranus and Neptune, sending back data and spectacular close-up photographs of the four giant outer planets.

Because the probes were destined to leave our Solar System and head out into interstellar space, they contained greetings from the Earthlings who sent them. A team led by astronomer Carl Sagan selected images and sounds that were recorded on gold-plated discs mounted on the spacecraft. There are images of buildings and insects and people. And sounds of whales and birds and thunder, popular, classical and traditional music from around the world, and spoken human greetings, in 55 languages.

STONE: "I think the main legacy of Voyager is to, in fact, have opened up our solar system in a way which was not possible before the Space Age. It revealed all of our neighbors in the Solar System, and showed us how much there was to learn and how diverse the bodies are that share the Solar System with our own planet Earth."

That's Voyager project scientist Ed Stone. Voyager 1 is now more than 15 billion kilometers from Earth, Voyager 2 more than 12. And they're still working, still sending back scientific data every day.

More than 4 million people around the world became infected last year with HIV, the virus that causes AIDS. For more than two decades there has been continual progress in medicines to treat AIDS, but little movement in efforts to develop a vaccine against the virus. This week almost a thousand researchers from 47 countries came to Seattle, Washington, to reassess their approach and develop new strategies for finding a vaccine. Patricia Murphy has more.

MURPHY: If there's a message that conference organizers want to get out to researchers, it's to start thinking differently about their approach to the virus. For nearly two decades scientists have focused most of their vaccine research on infection-fighting antibodies in the immune system with little to show for it. Only in the past five years have researchers shifted their attention to so-called killer T-Cells to attack the virus, rather than trying to prevent the infection in the first place.

Conference co-chair Dr. Jose Esparza says scientists have been handicapped by the lack of a natural defense against HIV to use as a model.

ESPARZA: "Nature has not invented a protective immune response as it has happened with measles or with smallpox or with other diseases for which we have vaccines. There is room for optimism [though] because humans have a history of beating nature."

Dr. Esparza says researchers believe that if they can manipulate the body to build an immune response before infection, they can then prevent HIV transmission. But he cautions that such a vaccine may be years away.

ESPARZA: "Last year, we have licensed the rotovirus vaccine that has been used. But the virus was discovered in 1974, 10 years before HIV. It took so many years to develop. That's the nature of this kind of research. We do research in healthy human subjects. Safety is our primary concern. And by the way, rotavirus is a good example of a vaccine that doesn't prevent infection. It prevents disease. So there are many examples in vaccinology that we can learn from. There's a lot of information there."

Conference chairman Dr Lawrence Corey envisions an effective HIV vaccine having a huge impact.

COREY: "There's a lot of mathematical models that actually say that a lot of transmission of infection occurs during the very early periods after acquisition in which the viral loads go up to 10 million, 20 million, 50 million.... And a vaccine that actually aborted that may actually have a larger impact on the transmission than we actually even hypothesized."

Most scientists have accepted the idea that you cannot hope to control the spread of HIV by controlling people's behavior — warning against things like unprotected sex, IV drug use, and HIV transmission through breastfeeding.

Dr Glenda Gray knows this all too well. She co-founded a prenatal HIV research unit in Soweto, South Africa, where HIV is epidemic. For HIV-positive South African mothers, she says, possible transmission through breastfeeding is the lesser of two evils.

GRAY: "Imagine every time you let your baby [nurse] and you're HIV infected and you know there's all this virus in your milk and you have to give it to your baby because the other choice of death is so much worse. Women just don't have a choice in Africa. We have to give them that choice. And so you can change the world or you can find a vaccine. And sometimes it's easier to find a vaccine than you can change the world. "

Dr. Gray is currently one of the researchers conducting HIV vaccine trials in South Africa. Many researchers are hopeful that an important piece of the HIV vaccine puzzle is being put in place right now. Dr Gray's current study is part of the HIV Vaccine Trials Network. It's the world's largest AIDS clinical research program. In collaboration with the U.S. National Institutes of Health, the program is testing 17 different experimental vaccines on five continents. For Our World, I'm Patricia Murphy in Seattle.

Another virus in the news this week, is being linked, perhaps surprisingly, to obesity.

For years, the conventional wisdom has been that people gained weight because they ate too much, didn't exercise, or were unlucky enough to inherit the wrong genes.

But over the past few years evidence has been emerging that a common virus may play at least a partial role in the global obesity epidemic.

Researchers first associated viruses with obesity in animals 25 years ago, and in 2005 a study showed that infection with a virus called AD-36 is associated with obesity in humans. People who had been infected with the virus were more likely to be overweight.

AD-36 is one of a family of bugs called adenoviruses that cause respiratory and eye infections.

Results of a new study announced this week show that the virus can turn human stem cells into fat cells.

PASARICA: "And what I observed for the first time is that this virus is inducing stem cells to become pre-fat cells and store more fat, therefore becoming larger fat cells — some kind of a fattening effect of the virus."

And Magdalena Pasarica of Louisiana State University says cells that were not exposed to the virus did not develop into the pre-fat cells.

The AD-36 virus is very common — one U.S. study indicated as many as 30 percent of people have been infected with the virus at some point, though there are no worldwide figures.

Pasarica stresses that the AD-36 virus is apparently only one contributing factor, and not the sole cause of obesity.

PASARICA: "Not everybody is susceptible to all viral infections, as we know. So you can be infected and not [be] obese or, you know, you can be obese and not infected with the virus, certainly."

Magdalena Pasarica presented her research this week to the American Chemical Society's National Meeting in Boston.

With obesity such a major global health concern, there is of course the possibility that identifying and understanding the viral cause of obesity could lead to a new kind of treatment.

PASARICA: "We have to remember that obesity is determined by multiple causes, and one of the causes might be this virus. And the easiest way [to block it] is to have a vaccine that will prevent development of obesity with origin of this virus. So our long-term goal, obviously, is to treat or prevent obesity of adenoviral origin."

A vaccine may be the long-term solution, but for now there is, unfortunately, no magic bullet, so you have to do what the experts advise: watch what you eat, and try to get some good exercise at least a few times a week.

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

Today, a different kind of legal website.

In many countries, the law is defined by the statutes passed by parliament. In the United States, however, we follow the British-based Common Law system, where the decisions of judges who interpret the statutes — caselaw, it's called — can be just as important, if not more so. For centuries, the cases were published in lawbooks that impressively decorate lawyers' offices. Today, though, lawyers are more likely to use privately-published online databases to find relevant cases. They're expensive, though, which means most people can't access them. Columbia University law professor Tim Wu aims to change that.

WU: " is a different way of finding caselaw — the nation's cases written by its judges. Now that may not sound like a big deal, but the truth is right now it's very hard to find the nation's caselaw."

AltLaw dot org wants to bring that caselaw into an online, fully-searchable and free database.

WU: "Our target audience is the general public, lawyers who want to save money, academics and, you know, we don't really know what's going to happen with it. It's still very new and preliminary. It's not a full replacement yet, but it's a start." is still in its infancy, and the cases it's posted online are limited to those published by the Supreme Court and other federal appeals courts for the past 10 years or so — no lower courts, and no state courts, either, at least for now. To add those will be time-consuming and expensive, but Prof. Tim Wu says he and his colleagues are inspired by the success of the free online encyclopedia, Wikipedia.

WU: "No one thought there would be a non-commercial free encyclopedia that would be as good as or better than some of the other encyclopedias out there. And so our idea is, once you start something, who knows where it will go. And it's about time that the legal profession, which is always a traditional profession, sees some of the benefit of the information revolution."

Searchable U.S. court decisions for the rest of us at org, or get the link from our site,

MUSIC: Henry Kaiser & David Lindley — "I Fought The Law"

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

Ever since human beings first experimented with growing their own food, they have saved seeds for use in future crop plantings. Agricultural technologies and genetic science have advanced since then. Collecting, preserving and storing the living, reproductive material of plants — called "germplasm" — is more important than ever. VOA's Adam Phillips visited a facility in upstate New York where they do just that.

PHILLIPS: Some people collect stamps or coins. Philip Forsline collects germplasm.

FORSLINE: "When you're a curator, you want to get the most diverse collection of whatever you're collecting. So my colleagues have the genetic material — germplasm — for some of the vegetable crops — tomatoes, onion, cabbage and cauliflower, and some of the cucurbits like squash."

PHILLIPS: Forsline is the research director at the Plant Genetic Resources Unit in Geneva, New York. Around the country, a network of similar facilities, also known as "seed banks," hold a vast collection of plant materials.

The Geneva facility houses the largest and most diverse collection of apple seeds and trees in the world. Apples happen to be Phillip Forsline's specialty. But he says that safely archiving all crop genetic material is a fundamentally important task, especially in the case of the world's major food crops like wheat, soybeans and maize.

FORSLINE: "Most of our crops are what you would call kind of a monoculture. So if a disease were to come along and it's a new disease, it could wipe out most of the crop because it's so genetically non-diverse. It's very important for us to have these, what we call "ex-situ" collections which brings in this germplasm to improve the crop."

PHILLIPS: Crop quality and health can often be improved by carefully cross-breeding domesticated and wild specimens of the same species. For example, U.S. commercial apple trees are often felled by diseases like fire blight and apple scab. Forsline and his team have made several trips to the forests of Kazakhstan, where the apple originated, to collect wild apple seeds that have evolved a resistance to apple scab.

FORSLINE: "Apple scab is a fungal disease — it's called Venturia inaequalis — that is endemic in this area of Kazakhstan, as is the apple. So the apple has co-evolved with the disease. We'll find the resistant ones and introduce those into our collection and make them available to breeders to improve the apple so we'll have scab-resistant apples."

PHILLIPS: Most of the seeds at the Geneva facility are stored in huge walk-in freezers.

ROBERTSON: "It's at minus 20 degrees Celsius so we can keep our seed up to a hundred years depending on the crop. We have them on movable shelves so we don't waste any space."

PHILLIPS: Larry Robertson, the Geneva seed bank's vegetable curator, says his main job is germinating and cultivating seed samples. If a seed sprouts, it shows the stock is still viable.

Plant breeders routinely request samples of these viable seeds from the facility and experiment with new genetic strains that produce plants with new traits.

Last year, the Plant Genetic Resources Unit sent out 5,000 seed samples; 40 percent of these samples went to breeders and researchers abroad. South Korea got a large variety of onion seeds, for example, and Turkey received valuable germplasm of crops such as cabbage, cauliflower and broccoli.

Phillip Forsline says he is glad to spread the seeds around. Because plant diversity is key to our survival, this germplasm must be protected and shared.

FORSLINE: "If it's lost, it's lost forever. You can't recreate germplasm. You think of air and water and energy sources. Those are all resources. Well, germplasm is just as much of a resource. It's a legacy and a resource for all of mankind for all of the future."

PHILLIPS: Boosted in part by alarm over global climate change, and the ongoing destruction of many of the earth's natural plant habitats, a worldwide movement to preserve this resource seems to be growing. The world's largest germplasm repository, called the Svalbard Global Seed Vault, is scheduled to open in Norway next year. For Our World, I'm Adam Phillips reporting from Geneva, New York.

Finally, today ... Americans are having sex in their sixties, their seventies, even into their eighties.

That's one of the findings of a new study by University of Chicago researchers. They surveyed more than 3,000 older Americans to paint one of the most complete pictures ever of the sex life of people between ages 57 and 85. Researcher Linda Waite says it provides an important benchmark to understand what normal sexuality is as people age.

WAITE: "The population of the U.S. and many, many other countries in the world is aging. Aging adults are healthier than they've ever been. And this study tells us what older adults experience and how they feel about it."

According to co-author Stacy Lindau, most of the people in the study had a spouse or other partner, and most of those who did reported having sexual activity in the past 12 months.

LINDAU: "An interesting finding is that among those who were sexually active, the frequency of sexual activity, which was two to three times a month or more, was not dissimilar from what Ed Laumann and his colleagues found in the study of 18-59 year olds. So what that suggests is that if one has a partner, the frequency of sexual activity doesn't change a whole lot across age groups."

The Ed Laumann she refers to is another co-author on this study.

The researchers found that sexual activity did decline with age. But much of that decline is related poor health in old age or the death of a partner, not necessarily a loss of interest.

Both men and women were more than twice has likely to have said they engaged in sexual activity in the past year if they considered themselves in excellent or very good health, compared with those who described their health as fair or poor.

Even though sexual problems can signal other health issues, the survey found that only about 30 percent of participants said they had discussed sex with a doctor since age 50.

Georgeanne Patmios of the U.S. National Institute on Aging, who was not part of the survey team, welcomed the study, which she said would provide doctors some guidance as to what kind of sex life their older patients might have.

PATMIOS: "Despite the aging of the population, little has been known about sexuality among older adults, how sexual activities change with age and how sexual activities and problems are associated with health. These are the first comprehensive, nationally representative data on sexual activity, behaviors and problems in relation to health status among older Americans."

Co-author Stacy Lindau said it might also help doctors bring up issues of the sexual health of their patients, a matter which can sometimes be embarrassing on both sides of the stethoscope.

Another change noted in the study is the type of sexual activities engaged in. Co-author Linda Waite says that as people age they are more likely to engage in other types of sexual activity, rather than intercourse.

WAITE: "That declines slightly as people age, with more cuddling and kissing and snuggling as the primary activity."

The study on sex and older Americans was published this week in the New England Journal of Medicine.

MUSIC: "Our World" theme

That's our show for this week. We're always interested in your comments or your science questions. Email us at Or use the postal address —

Our World
Voice of America
Washington, DC 20237 USA

Rob Sivak edited the program. Felicia Butler 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.