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Our World — 21 April 2007


This transcript is provided as a service; there may be some variation between it and the program as broadcast.

MUSIC: "Our World" theme

Straight ahead on "Our World," A startling drop in breast cancer rates ... a challenge to old dogma on diabetes ... and sustainable agriculture in an unlikely place:

CAPLOW: "The joke about New York City kids is that they think that tomatoes grow in the supermarket, so this is a wonderful way for kids to understand where food comes from and what a plant needs to grow and how that works."

Observing Earth Day, why light pollution matters, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

Scientists say the number of breast cancer cases in the United States dropped sharply in 2003. That's when millions of women stopped taking hormone replacement therapy after researchers found a link between it and breast cancer. VOA's Jessica Berman reports

BERMAN: In a special report published this week in the New England Journal of Medicine, a team of US researchers found the number of new breast cancer cases fell almost seven-percent in 2003 from 2002 levels, and remained unchanged in 2004.

The drop means that 44,000 fewer cases of breast cancer were diagnosed in 2003 and again in 2004. Prior to this study, the American Cancer Society was reporting an estimated 300,000 new breast cancer diagnoses each year.

The driving force behind the decline emerged from a large study known as the Women's Health Initiative. The study involved 16,000 participants and looked at whether hormone replacement therapy prevents heart disease in post-menopausal women.

The hormone replacement therapy study was halted suddenly in 2002 when investigators found that the drugs promoted ovarian cancer. Millions of women stopped taking them.

Peter Ravdin is a cancer specialist at the M.D. Anderson Cancer Center in Houston, Texas and author of the paper in the New England Journal that noted the sharp drop in breast cancer diagnoses.

RAVDIN: "You know, in retrospect, it is not surprising at all."

BERMAN: The results of the 2002 Women's Health Initiative showed that women past their child-bearing years, who were taking hormones for five or more years, had the highest cancer risk.

Ravdin says he is not surprised by that finding either.

RAVDIN: "One of the things that always strikes me is this business about natural products. How can something natural be bad for you? You know, it is natural for a woman to have estrogen in her body? Well, it is. But maybe it is not that normal for her to have estrogen in her body when she is 60."

BERMAN: Meanwhile, in an article published in the British medical journal The Lancet, researchers following one-million post-menopausal women for 15 years have reported an additional 1,000 deaths they suspect were a result of hormone replacement therapy. Jessica Berman, VOA News, Washington.

Worldwide, some ethnic groups are developing type 2 diabetes at higher rates than others. Type 2 diabetes is the form of the disease that develops in adults, most frequently those who are overweight. Health reporter Rose Hoban reports on the latest research on the link between diabetes and ethnicity.

HOBAN: For decades, some scientists have held that early human groups that experienced cycles of feast and famine evolved so that in times of famine their bodies were able to conserve scarce calories. They believe that today, people from those populations no longer experience famine, but their bodies still store calories 'too efficiently'… making them more susceptible to obesity and therefore, diabetes. This idea is known as the thrifty genotype hypothesis.

But some are starting to question that idea. Anthropologist Michael Montoya from the University of California at Irvine worked with a team of researchers to review the mass of literature surrounding the hypothesis. They found it was based on flimsy evidence.

MONTOYA: "It doesn't make evolutionary sense. in fact, all human groups would have had this genotype because all human groups experienced feast and famine cycles equally. And furthermore the ethnic minority groups that currently have type 2 diabetes don't have a dissimilar long-term evolutionary history from those groups that currently do not have type 2 diabetes. So it must be something else."

HOBAN: Montoya says medical researchers have found that many factors can contribute to the development of type 2 diabetes, including activity level, stress and low birth weight … not only genetics.

MONTOYA: "When you add up the 250 and so genes that have been looked at putatively responsible for type 2 diabetes, together they only account for one percent of the global prevalence of the disease."

HOBAN: Montoya says social science research shows groups THAT experience long term social disadvantage consistently tend to have higher rates of type 2 diabetes:

MONTOYA: "The common sense is that of course behavioral factors are vitally important to who gets overweight and who can manage their disease, who can understand complicated medical directions and follow them. So of course, socio-cultural factors are central."

HOBAN: Montoya says he's surprised that so many scientists have sought explanations for the worldwide increase in diabetes using a framework he considers to be faulty. He hopes his group's paper will prompt better debate about the thrifty genotype hypothesis. His paper appears in the journal Perspectives in Biology and Medicine. I'm Rose Hoban.

There was a new moon in the sky on Tuesday. That's the phase, of course, when the moon's dark side is turned toward Earth. Once, that meant very dark, star-filled nights across the globe. But increasingly, our view of the night sky is being obliterated by the diffuse glow of urban and suburban lighting.

For years, this light pollution has been a concern of astronomers, whose ability to observe the heavens was affected.

Veteran astronomer Dave Crawford says increasing light pollution means many of the world's most famous observatories can no longer do cutting-edge astronomy.

CRAWFORD: "Mt. Wilson, where the expanding universe was discovered and worked on by [Edwin] Hubble can't do that kind of stuff anymore. Palomar is severely impacted. And so one goes to North-central Chile or the Big Island in Hawaii or the Namibian desert or other places. And yet even there, of course, these being nice, clear, wonderful places, [they] tend to get impacted by people moving in and bringing their lights along with them. So it's a real problem."

Crawford now heads the International Dark-Sky Association, which is working to raise awareness of the issue.

He says much light pollution comes from poorly-designed lighting fixtures — such as streetlights that don't direct their light downward. Dark sky advocates say it's wasteful and creates pollution from unneeded power generation. The light hits dust particles and water molecules in the atmosphere, diffusing into a glow that covers the skies around big cities and increasingly in less-populated areas as well.

Crawford says the absence of dark nights may also disrupt biological cycles.

CRAWFORD: "Whether it's sea turtles, or birds, or trees, or plants. There's no question that recent studies indicate that the lack of a good circadian rhythm — you know, the day/night cycle — is impacting human health. We need that day/night cycle. Everything has had it over the entire history of the earth. And to take it away in only a few decades is a dangerous thing to do."

Several years ago Jennifer Barlow, who was then a high school student, launched a campaign to get people to turn off their lights — at first for just one night — so they could see the night sky better. The campaign led to National Dark Sky Week, which began Tuesday with the new moon. It's not an official event, though many in the astronomy community have embraced the idea. Barlow, who is now a student at the University of Virginia, says Dark Sky Week is more about raising awareness of light pollution than actually getting people to turn off their lights.

BARLOW: "Really turning off the lights for one week isn't going to do very much. But [by] becoming more aware and learning about the proper lighting fixtures, we'll be able to make the skies have a better quality and be darker for years and years to come."

The quality of the night sky is important to Dennis Erickson, a Chicago high school teacher and advocate of sidewalk astronomy, where amateur astronomers take their telescopes out on the streets so city dwellers can see some of the wonders of the night sky. But in a big city like Chicago, he says light pollution obscures all but the brightest objects in the sky, and that robs people of the sense of wonder that a really dark, star-filled sky can bring.

ERICKSON: "To get that serious, awe-inspiring feeling of looking at the night sky — especially seeing that Milky Way — when that shows up, it sort of gives you a chill down your back, and you wonder what in the world is out there, is there life out there. And now, if you live in the city and don't get out in the country, you don't experience that, and, you know, most of our inner city kids do not get out, and they never see that beautiful Milky Way."

Meanwhile, Jennifer Barlow has some suggestions for what you can do for a darker night sky.

BARLOW: "Turn off the lights. That's one of the most important things, because if people don't participate, then it's not going to work. Actually tell other people, because not everybody's going to hear about it. And also to go out and look at the sky and just see what the dark sky has to offer us. Hopefully that will encourage people to get better lighting and be more aware about light pollution."

Jennifer Barlow is the originator of National Dark Sky Week. If you want to see the extent of light pollution, we've got a satellite view of the Earth at night linked from our website,

On the darkest nights the sky will be filled with stars, and orbiting many of them are planets that scientists are just beginning to detect. That's the subject of our Website of the Week, when we showcase interesting and innovative online destinations.

This week, it's a website highlighting what once seemed impossible — the search for planets orbiting distant stars. More than 200 have been discovered so far, and you can learn more about those extra-solar planets, as they're called, and how astronomers look for them, at

JACKSON: "Planet Quest is a one-stop shop for the general public to keep up with news and discoveries of planets around other stars, and a place to learn about the science and technology of planet finding. And also, to learn about future missions NASA is developing that will be able to detect Earth-like worlds."

Randal Jackson is a web producer at NASA's Jet Propulsion Laboratory in California, the home of PlanetQuest. Scientists have several methods to detect planets in the far reaches of space, using both ground-based telescopes and spacecraft. On PlanetQuest, with its multimedia presentations like the 3D New Worlds Atlas, all you need to discover new worlds is a computer.

JACKSON: "And you can actually take your mouse and explore this little quadrant of our galaxy, which is about 1,000 light years across. And if you click on a specific star, you zoom in for a close-up of the planetary system around that star, and then you can print out a sky map, and then you can go out and try to locate that star in your backyard using a telescope or binoculars, or in some cases you can see these stars just with your naked eye."

PlanetQuest is designed for the general public, so it's easy to understand, and the site also includes an extensive library of material for use by students and teachers.

JACKSON: "We have a student activities guide. We direct people to some experiments they can try in planet-finding, simulating planets on their desktop or in the lab. There are math exercises. There's a demonstration you can use to show how planets make stars wobble, just using very commonplace objects like a couple of balls, a ruler and a string."

The first planet outside our solar system was discovered in 1995, and new ones are being discovered all the time. Keep up with the quest — or catch up on what you've been missing — at, or get the link from our site,

MUSIC - "Johnny Quest"

VOA's quest for science and technology, this is Our World. I'm Art Chimes in Washington.

An urban farm might seem out of place on a floating barge on New York's Hudson River, with the Manhattan skyline towering above. But this new approach to sustainable agriculture is ready to launch, as VOA's Adam Phillips discovered.

PHILLIPS: Ted Caplow stands on the deck of a barge that's like no other on the New York waterfront. Part high-tech farm, part laboratory, and part floating classroom, the New York Sun Works Science Barge sports solar panels, wind turbines, a couple of greenhouses and other gear aimed at demonstrating sustainable agriculture in one of the world's most densely-packed cities.

The Science Barge project, which is set to launch next month, aims to show how urban areas like New York can support agriculture using recycled water and renewable energy.

CAPLOW: "When we grow food out in the country, we use a tremendous amount of water and land and fertilizers. And all these things have a large impact on the environment in the countryside. By moving food production into the city, we save a lot of land and, at the same time, we bring the food closer to the consumer."

PHILLIPS: There's not a lot of vacant land in Manhattan that would be suitable for farming. But Caplow says that farms don't have to be on ground level.

CAPLOW: "There is a lot of space up on the roof. In New York City for example, we have approximately 5,000 hectares of available space just on existing rooftops. That is space that is open to the sky, so there's plenty of sunlight where we can grow vegetables. But we can't grow vegetables in the city the same way we'd grow them out in the country."

PHILLIPS: On a traditional farm, there is one horizontal surface where plants are grown. It's the surface of the earth itself. But the Science Barge folks say many crops can be grown in containers stacked one atop the other, somewhat like a high-rise apartment building. Sun Works greenhouse director Jenn Nelkin says this is a good way to grow certain plants.

NELKIN: "So instead of having just a horizontal row of plants, here I have 40 plants instead of one that might take up that same square foot space if we were growing everything horizontally. So we'll be growing our basil and parsley and edible flowers. This is [also] a great system for strawberry production. So that's to get some vertical space out of short crops."

PHILLIPS: An abundance of other crops, including tomatoes, lettuce, cucumbers, and other vegetables are flourishing in the New York Sun Works greenhouses. They're grown using hydroponic technology where the roots are immersed in trays of nutrient rich water, not soil.

The water itself comes either from rainwater stored in an onboard tank, or from the Hudson River itself. Sun Works staff member Viraj Puri explains that the river water is purified and desalinated by a reverse osmosis machine.

PURI : "You pump water up, a lot of pressure builds up and it is passed through a membrane. It separates the salt from the water and the brine goes back into the water."

PHILLIPS: This machinery and sophisticated environmental control devices and computers, are powered by wind turbines, solar power, and bio-diesel fuel made from used cooking oil from city restaurants. But high productivity and new technology are only part of the project's mission. New York Sun Works director Ted Caplow says the barge is also a floating classroom that will educate Big Apple youngsters about how food is actually produced.

CAPLOW: "The joke about New York City kids is that they think that tomatoes grow in the supermarket and all the food just comes from the shelf somewhere. It's a joke but a lot og times it's pretty close to the truth! So this is a wonderful way for kids to understand where food comes from and what a plant needs to grow and how that works."

PHILLIPS: Knowledge and respect for those and other natural processes will be on the minds of many of the world's citizens as they celebrate Earth Day this Sunday. For Our World, I'm Adam Phillips reporting from New York.

Earth Day began in 1970 with a dream to celebrate and protect our fragile planet. The event launched an environmental movement in which millions of people, first across the United States and then around the world, pressed for new laws to protect air and water resources and endangered species and ecosystems.

This year, according to the Earth Day Network, a non-profit group that's coordinating the international observance, one billion people across the globe are expected to participate. VOA's Rosanne Skirble has this sampling of how some Americans will be marking the special day.

SKIRBLE: Americans will attend a multitude of events like the environmental cleanup in East Peoria, Illinois.

BLEICHNER: [TELEPHONE] "Good morning, Planning and Development."

SKIRBLE: VOA caught up with Barbara Bleichner at East Peoria's Beautification and Planning and Development office, the sponsor of the town's Earth Day's Operation Clean Sweep.

BLEICHNER: "We have a lot of volunteers from boy scouts to church groups and we supply them with gloves, safety vests and we go out and we clean up the major city streets that nobody seems to respect and the [people] throw out all their litter. So, we pick it all up."

SKIRBLE: Bleichner says Operation Clean Sweep is a great way to show community pride.

BLEICHNER: "We just try to make it look a little bit nicer, make it more eye appealing."

CLARK: [TELEPHONE] "Thank you for choosing Salonamour. This is Deeann."

SKIRBLE: Deeann Clark is manager of Salonamour, a beauty shop in Walnut Creek, California not far from San Francisco. She says the salon has participated in Earth Day for the last five years doing what stylists do best:

CLARK: "We have a local outdoor mall and we are going to be doing haircuts outside on a stage in the middle of this outdoor mall for donations. Our stylists are going to be cutting on stage and 100 percent of the proceeds go to our local organization."

SKIRBLE: That organization is the Bay Institute, a water resources group that advocates for the health of San Francisco Bay.

CLARK: "We are here to make a stand and be leaders in our local community and say that we have more values than just doing hair, that we can connect doing hair to a larger cause and these are things that we do care about."

SKIRBLE: Reforestation is the focus of Earth Day on the Edwin B. Forsythe national Wildlife Refuge, a protected marshland that runs along the New Jersey coast. Volunteer coordinator Sandy Perchetti says scout groups and local high school volunteers will plant some 600 trees.

PERCHETTI: "When they get done planting trees they are going to come back here and get a little lesson on the importance of trees and how we can help save energy by planting a tree."

SKIRBLE: Perchetti says the event underscores the value of good stewardship and is largely targeted to young people.

PERCHETTI: "We have to teach them the importance of taking care of their home. They can come back to this refuge when they are grandparents and show their kids, "I planted this tree. This forest is part of mine. This land that it is planted on belongs to the American pubic."

MUSIC: "Welcome to the World" — RatDog with Bob Weir

SKIRBLE: Legendary Grateful dead artist Bob Weir and his band RatDog will headline at a free Earth Day concert in San Francisco's Golden Gate Park as part of the Green Apple Music and Arts Festival. Executive Producer Peter Shapiro says Green Apple is the largest Earth Day event in the country.

SHAPIRO: "It brings Earth Day to 70 music venues across America in New York, Chicago and San Francisco."

SKIRBLE: "… which includes the free concert in Golden Gate Park and free star-studded acts in New York's Central Park and at Chicago's Lincoln Park Zoo. Shapiro says a host of environmental groups will set up information booths at the venues on a multitude of green issues.

SHAPIRO: ""And doing all these concerts we think we are achieving our goal which is to buildup Earth Day. We hope in the next years [to be in] more cities with Green Apple Festival in every Earth Day weekend all over the country. That's our goal."

SKIRBLE: Shapiro says at its core Green Apple Festival is a call for action to protect the planet, a mission it shares with the thousands of events celebrating Earth Day across America and around the globe. I'm Rosanne Skirble.

MUSIC: "Our World" theme

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

Our World
Voice of America
Washington, DC 20237 USA.

Rob Sivak edited the program. 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 Our World.