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Our World Transcript — September 10, 2005

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" ... Hurricane Katrina and the New Orleans levee system ... A backpack that makes its own electric power ... and the threat to Giant Pandas from their one-food diet...

TAYLOR: "People have moved into lower elevation areas where there are other bambooo species the pandas could move down into and use, and those are now gone. So there's no alternative place for them to go."

those stories, caring for injured birds of prey, and more... I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

The city of New Orleans sits largely below sea level in a bowl bounded by the Mississippi River and Lake Pontchartrain. It relies on more than 500 kilometers of levees, a system of drainage canals and floodgates, and a network of pumping stations to keep it from filling with water. The arrangement has worked fairly well for more than 40 years. What happened this time? And what can be done to ensure it doesn't happen again? Faith Lapidus has our report.

LAPIDUS: Levees were first used more than 5,000 years ago in ancient Mesopotamia to control the destructive seasonal flooding of cities along the Tigris and Euphrates Rivers. According to Rafael Bras, Professor of Civil and Environmental Engineering at the Massachusetts Institute of Technology, today's levees serve the same purpose.

BRAS: "When you have a situation like in New Orleans, where large portions of the land are below sea level or subject to tidal or storm flooding, then the only way ultimately to prevent disaster and flooding is to separate the large body of water from whatever the inner part (is) - lagoons, land, etc. When properly operating, and well-designed and maintained, levees in many situations are the only way to deal with the issue.

LAPIDUS: The levees that protect New Orleans today date from the 1960s. They were built in response to earlier floods that had caused severe damage to the city. They were considered state of the art at the time.
Journalist John McQuaid says the engineers who designed that system of levees did so without the benefit of today's advanced technology.

McQUAID: "They didn't really know, since they didn't have computers up and running that could model storm surges and the like, exactly what level of protection it afforded, in terms of how likely it was to be over-topped, but they were pretty proud of it and thought it would last a long time. They eventually got computers, and they did a rating for exactly the strength of storm the levees could withstand, and it was a fast-moving Category 3 storm, anything stronger than that, the levee system could not be guaranteed to protect the city."

LAPIDUS: And the levees were no match for Katrina -- which came off the Gulf of Mexico as a much stronger, category 5 storm… one of the most powerful hurricanes to hit the United States in years. It was heading straight for New Orleans but veered off at the last minute. The city was spared a direct hit. But a storm surge in its wake pushed water from Lake Pontchartrain over the floodwalls and levees, eating at their foundations until large sections collapsed.

John McQuaid co-authored a series of articles published in 2002 in New Orleans' main newspaper, the Times-Picayune, that described the city's vulnerability.

McQUAID: "This issue is something that every public official was aware of, we published our series, which splashed it all over town, and the state, and most people who lived in New Orleans were aware that this was a risk. Most people, I think, hoped and prayed that it was a relatively remote risk. But in part, New Orleans always had this fatalistic undercurrent to its character from the very beginning, and so I think some people thought, well, we'll let the good times roll and we'll deal with it when it happens."

LAPIDUS: The reporter puts more of the blame on the government agencies and bureaucracies that evaluate risk and decide much money to spend to counter that risk.

But it's not just a question of money, says Neil Grigg, a professor of civil engineering at Colorado State University. Levees - like roads, bridges and other infrastructures - need constant attention, too.

GRIGG: "Once the levee's built and it's in there, and people forget about it, as they will do, things happen to make its condition deteriorate. Animals can burrow into it, weeds and trees can grow, water can weaken it, so it needs a lot of maintenance and a lot of attention, continuously, if it's going to be something you can rely on. [OPT] It's like these other infrastructure problems, it's not something you can just put in place and forget about it, it requires a lot of attention in the future. [END OPT]"

LAPIDUS: Civil engineers agree that the future of New Orleans must include a rigorous and regular levee maintenance program, and a more robust pumping system… and money to pay for it all.
[OPT] MIT Professor Rafael Bras recommends finding a way to increase the sediment that the Mississippi River once deposited to build up the land on which New Orleans sits.

BRAS: "What you have in New Orleans is a delta, and if you do not supply the sediment to the delta then in essence, you have increased erosion and that erosion will endanger your situation further, one way of dealing with the vagaries of nature is to let nature help also by making sure we have enough sediment (as possible) getting to delta." [END OPT]

LAPIDUS: Despite efforts to protect New Orleans, civil engineering professor Neil Grigg cites a 1993 study that concluded it was futile to try to stand against one of nature's most powerful events.

GRIGG: "What we need to do is to learn to adjust to those, and not to live in vulnerable areas, to be ready to evacuate, to have warning systems, and to use these sort of non-structural approaches rather than to build levees higher and higher and stronger and stronger. That just doesn't work."

LAPIDUS: Despite the inherent peril of living below sea level, officials so far are pledging to rebuild the city. Engineers stress that a new New Orleans will need better protection from the surrounding water … and better emergency plans in case efforts to keep out the water fail. I'm Faith Lapidus.

Meanwhile, engineers this week began pumping floodwaters water out of New Orleans into adjacent Lake Pontchartrain.

There's really no other place to put the water, but environmentalists are expressing concern that the polluted water -- including a foul mixture of decaying human and animal bodies and waste, household and industrial chemicals, and fuel products including gasoline -- will degrade the waters of the lake.

The head of the U.S. Centers for Disease Control, Dr. Julie Gerberding, minimized the threat to the New Orleans lake.

GERBERDING: "It's not likely to have any long term impact on the lake. This is the kind of thing that happens any time it floods, even if the bacteria are coming from pastures instead of the kind of sewage problem we're having in New Orleans. Over time, these bacteria will dissipate and die, but the short-term issue is [that] they could be concentrated in the waters in the city, and it's a health hazard in that context."

In the short term, however, the Lake Pontchartrain ecosystem will certainly suffer. The pollutants will be diluted in the large but shallow lake, but experts expect fish and other marine life will be killed as the toxic water is pumped out of New Orleans.

Electric power is slowly being restored to the flood zone in and around New Orleans, which will help survivors and rescue workers recharge their mobile phones and other battery-operated equipment.

Today, scientists, rescue workers, military forces and others going into remote areas need to carry batteries to power a wide range of mobile devices.

Now, scientists at the University of Pennsylvania have developed a new way of generating electric power by harnessing the up-and-down motion of a backpack.

Lawrence Rome described his invention in the journal "Science."

ROME: "I've developed a passive device called a suspended-load backpack, which allows the user to generate electricity when they're walking down the streeet, and this electricity is important for anybody working in a remote area, whether they're using cell phones, GPS or other communication or scientific devices."

The backpack has a rigid frame, and the load is attached to the frame with springs. The motion of the load is then transferred to a small generator using a rack-and-pinion arrangement like many cars use for steering. The system produces up to about seven watts of electricity in normal use -- enough to recharge small, battery powered devices commonly used in remote areas.

Professor Rome says the system works best with a full backpack.

ROME: "Definitely the more mass, the more electricity because there's more mechanical work that's being done, because you're moving a larger weight the same vertical distance. And another thing is, the faster you walk, the more electricity [you produce] as well.

So if the backpack is now generating power, you would think the person carrying it would have to work harder. And that's true. There is no free lunch. But apparently there is a discount.

ROME: "It's true, the metabolic rate goes up about three percent, but we were expecting it go up much larger [amount], and what that must mean is that the cost of just the walking part of it has actually had to go down."

When Prof. Rome talks about the cost going down, he is referring to the energy expended.

Because of this greater efficiency, it may be easier to carry loads using a spring-loaded backpack even if you don't need to generate electricity.

Commenting on the new backback in a separate article in Science, mechanical engineering professor Arthur Kuo of the University of Michigan said he expects that, as impressive as the new backpack technology is, there is a lot of room for improvement.

KUO: "This was just a prototype, so I don't think they had the opportunity to really experiment with the device and try different combinations of masses and springs. My expectation would be that if you got a lot more power than what they got -- so they generated about 4 watts -- and I think that there's no reason why they shouldn't get a lot more than that. And then, it's even conceivable that the total cost of walking and powering the generator could be lower than the cost of wearing a conventional backpack."

The backpack developer, Lawrence Roth, told me he has formed a company to commercialize his invention. I suggested the name "Power Pack," but he said they're going with "Lightning Packs," which is even better.

Time again for our website of the week. This time we highlight a website that serves as a virtual community for computer programmers and a source of free -- that's right, free -- computer software for users. At, the focus is on open source software.

BATES: "Open source software is software in which you not only have the program, but open source also philosophically says that you can have access to the source code as well. And that's the original stuff written by the programmers that the computer uses to actually run the applications."

Jeff Bates is a vice president at OSTG, the parent company of

The open source philosophy not only opens up the inner workings of the software, but invites anyone to contribute to it by modifying the program. provides an online gathering place where programmers can share ideas to improve the software product.

BATES: "We provide via the development tools, the resources, the web space, the e-mail lists -- all the things necessary to run a software project -- to the open source community. So we've got tens of thousands of developers across the world. And the unique aspect of it, is that all of it is free." is definitely a home for tekkies and geeks, but most of the site's visitors aren't programmers at all. They're computer users looking to download free software that in many cases is as good or better than commercial products, or fills a need that regular software publishers haven't yet addressed. Some of the most popular downloads are file-sharing programs such as BitTorrent, the instant messenger program GAIM, and a calendar program called WebCalendar. There are also about 1200 mathematics projects, 700 arcade games, genealogy programs, and on and on.

The software runs on Windows and Mac computers, and other platforms.

For a world of free, open source software, and a community of programmers who are philosophically committed to share what they are producing, surf on over to, or get the link from our site,

MUSIC: Do You Know What It Means to Miss New Orleans (Louis Armstrong's Dixieland Seven, 1946)

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

Apple Computer ended a flurry of speculation this week and unveiled a new version of its iPod portable music player and a new mobile telephone that allows users to listen to tunes as well as talk on the phone.

This is not the first cell phone that plays music, but as David Pogue wrote in The New York Times, the Rokr is the first with what he called "Apple's sense of style and polish," although other critics pointed out shortcomings, such as a 100-song limit.

The new iPod model, the elegant looking 43-gram "iPod nano" uses flash memory, not the tiny hard drive that powers most other iPod models. Wall Street Journal technology columnist Walter Mossberg called the nano "the best combination of beauty and functionality of any music player I've tested."

To somewhat less notice, portable music pioneer Sony also this week introduced a new, sleek line of digital Walkman models. Industry analysts predict that Sony and other makers of portable music players will have a difficult time competing against Apple's popular iPods, which now enjoy a commanding share of the portable music player market.

When we get a chance, we like to dig into the Our World mailbag and answer a science question. Today we have an email from Danfeng Zhang in Kunming, China, who wants to know about bamboo and the Giant Panda. The panda rely on bamboo for almost their entire diet, and that's a problem when bamboo plants die off, which they do in unison. Mr. Zhang wants to know if anything can protect the panda, which is an endangered species.

For the answer we turned to Alan Taylor, a professor of geography at Penn State University, who has studied the relationship between China's Giant Pandas and their main food. It's an interesting relationship because of the panda's reliance on bamboo as nearly its only food, and the unusual life cycle of bamboo.

TAYLOR: "What the bamboo does is, it grows for decades in a vegetative state, and then it flowers all at once and dies back. And in the mid 1970s, more than one species did this within the range of the pandas. And so when that occurs, the pandas have to move into an area where there's another bamboo species. And what has happened in terms of the interaction of the bamboos, pandas and people is that people have moved into lower elevation areas where there are other bambooo species the pandas could move down into and use, and those are now gone. So there's no alternative place for them to go."

Because our listener, Danfeng Zhang, is concerned about the panda, he wants to know if anything can be done to prevent the bamboo from dying. Penn State's Alan Taylor says some scientists have conducted experiments to see if they could control the bamboo flowering which precedes the death of the plant --

TAYLOR: "But to operationalize that or apply that to, you know, thousands of square kilometers where pandas live are really pretty unrealistic, I think, in the short or the long term, and the best approach to preventing them from declining in numbers is to try to maintain their habitat, or even actualy improve it expand it into areas where it has been recently lost. For example, many of the areas that have been set aside for pandas recently have had people living in them. And you could replant bamboo forests, for example, in areas that might have once been fields, or where it has been removed due to human activity. So that's probably the most effective way to maintain those populations and prevent their extinction in the long run."

Loss of habitat is a problem faced by many species as humans make the species' habitat our own. The reliance on bamboo and the unusual bamboo life cycle makes it a special challenge for the panda.

Thanks to Danfeng Zhang for asking about bamboo and panda. We'll be sending a special VOA gift to him as our way of saying thanks. If you've got a question about science, technology, health or the environment, e-mail it to, or listen for our postal address at the end of the show.

The vast landscapes of the American west are home to all kinds of wildlife, from bears and mountain lions to birds of prey such as eagles, hawks, kestrels and other raptors ... meat-eating birds that kill their food. Sometimes, these raptors get injured, either from natural or manmade causes. VOAs Adam Phillips reports from Peublo, Colorado, on one group of humans that tries to help them.

PHILLIPS: Hawks such as these are a familiar sight in the skies above the Raptor Center of Pueblo, Colorado.

PHILLIPS: The surrounding landscape -- canyons, mountain meadows, desert and trickling waterways - is a favored habitat for birds of prey, or "raptors," as scientists refer to these hooked-beak birds. Raptor Center director Diana Miller says those beaks are perfectly designed for ripping flesh. But she also admires raptors' large feet.

MILLER: "… Because they are just amazingly engineered for gripping power. You have this bird who weighs about a kilo[gram], and even though he weighs a kilo or so, he has feet that can grip (with a force of) like 20 kilos of pressure per square inch. And added to that power in the foot they have that large curved claw we call a talon, so they can pierce their prey with all that pressure behind it. So a one-kilo bird can kill a three or four-kilo animal."

PHILLIPS: The Center's more than 6,000 annual visitors also learn that raptors have excellent vision.

Diana Miller says that educating the public about the wonders of predatory birds is only part of the Center's mission. The facility also helps sick and injured birds in its twenty-five cage facility.

MILLER: "Wing injuries are very common from being hit by a car, flying into a power line, or getting snagged on a barbed wire fence. We see them hitting the reflective glass windows on office building in the city areas."

PHILLIPS: That's the sound of twelve barn owls, large nocturnal hunters with ghostly white underbellies. Most in the group were found as chicks by the side of a road.

MILLER: "You'll notice they have this weird posture and they are sort of bending over and they are rubbing their chin and cheek over their toes. And that's called "toe-dusting" and that's their defense posture.

PHILLIPS: The Raptor Center returns a bird to the wild only if it is likely to survive on its own. When a golden eagle named "Aquili" was brought in twenty years ago, it was clear she would live out her life in the Center's care. She was a young bird who was struggling to survive with untested hunting skills, as Ms. Miller explains during a brief mountain sun shower.

MILLER: "… And she found a deer that had been hit on the road and died. So she was scavenging, which birds of prey will do, and had eaten so much food because she didn't know when she would eat again - she just filled her stomach with tons of deer, that when a semi [truck] came down the road and she tried to get out of the way, didn't move fast enough and got hit in the shoulder and her shoulder got destroyed. So she's non-flighted."

PHILLIPS: Ms. Miller says they must be careful not to make things too comfortable for the birds or they may not develop the abilities they need to survive in the wild.

She picks a three-week-old rat from its cage, and enters a wire enclosure where some small American kestrels, a common North American raptor about a quarter of a meter tall, are waiting for dinner. For many of the youngsters here, killing their own prey is a new experience.

MILLER: "These are youngsters and they are just now learning how to hunt. So they've been really well-fed up to this point. So now we are bring just live food so he's got to work for his food. They are going to have to thin down a little bit to get their edge back."

PHILLIPS: Ms. Miller adds that, with or without that edge, and despite the rapport between raptors and their human hosts…

MILLER: "… There is the one thing they always want that you can't give them and that is their freedom.

PHILLIPS: At the Raptor Rehabilitation Center in Pueblo Colorado, I'm Adam Phillips reporting.

MUSIC: Our World theme

That's our show for this week. We're always delighted to hear from you. Ask us a science question … tell us what you like about the program, or what you don't like. Email us at Ourworld is all one word. Or the postal address is -

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Voice of America
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Our World is edited by Rob Sivak. Our technical director is Gary Spizler. 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.