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Our World Transcript — 29 April 2006

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" ... Teaching grammar to songbirds ... Restoring the Louisiana wetlands after the hurricane ... And a look back at Biosphere 2 ...

LEIGH: "The carbon dioxide kept increasing inside and the oxygen was decreasing. So we not only had an atmosphere that was not very healthy for humans, but we had a puzzle, we had a mystery."

Those stories, rocket scientists on our Website of the Week, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

We humans used to think we're so much better than all the other animals. We use tools. We use language.

For years, though, scientists have been chipping away at the idea. A wide variety of animals — from chimpanzees to dolphins — use tools in various ways. Lots of species communicate, too, though deciding exactly when to call that "language" can be controversial.

The latest contribution to the debate comes this week in the scientific journal "Nature." Tim Gentner of the University of California — San Diego has found that a common songbird can be trained to identify a common pattern that is a feature of many human languages.

SFX : STARLING natural

GENTNER: "One of the reasons that we're using European Starlings to look at these sorts of processing capabilities, these sorts of cognitive abilities, is that they are champion singers, they sing incredibly long songs and their songs have lots of little pieces or chunks — we call them motifs — that they string together in time."

The pattern Gentner is interested in is called "recursion." Many linguists consider it a defining characteristic of human language. It's where a phrase or a whole sentence is embedded inside another sentence. For example, you can embed the phrase "on the radio" inside the sentence "I listen to VOA — on the radio — in my room."

The researchers used actual starling sounds — motifs — and assembled them into a series of artificial starling songs, using different patterns, either simple, like this —

SFX: Starling - AB2

or complex — recursive — ones, like this —

SFX: Starling - A2B2 recursive

and they trained the birds to identify the more complex one.

GENTNER: "If it's a song created by the complex rule, then they have to press that button again. If it's a song created by the simpler rule, then they have to not press that button. So what we're doing essentially is associating two different behaviors with two different sets of songs."

Most of the birds could be trained to distinguish between the two patterns, although it took tens of thousands of tries before they could do it reliably. Still, that's better than cotton-top tamarins did in an earlier study. Tamarins are a small South American primate that are obviously much closer to humans than birds biologically, so I asked Gentner how he might explain the results.

GENTNER: "One is that there are, in fact, species differences. So perhaps tamarins that don't learn their vocalizations — songbirds have to learn their vocalizations; it's a parallel between songbird and human speech; they both need early exposure; if songbirds or humans lack that or miss out on that early exposure, then the vocalizations that they produce as adults will be deficient functionally, and tamarins don't require that same sort of early exposure. So that might be a potential difference, it might be a species difference. The other possibility is that tamarins could do it, but that the techniques that were used in that earlier study failed to show that ability."

Gentner adds that what he found out about the birds also tells us a bit about us humans.

GENTNER: "It's important for a number of different reasons. It tells us, first of all, a little bit about what makes us human. So it invigorates the debate about the uniqueness of human language and says, that, well, perhaps certain aspects of the way that we perceive patterned strings of sounds — words — are shared with other organisms. And that tells us, number one, a little bit about who we are as people and about our connection with the world at large."

Tim Gentner adds that it's also important because if other animals share some of the same language mechanisms that humans have, then it may be possible to study the biological basis of language with experiments that you couldn't ethically conduct on people.

We return again this week to hurricane-ravaged Louisiana, as we continue a series of reports on the health and environmental impact of last year's Hurricane Katrina.

This time, we look at the consequences of engineering the wetlands of the Mississippi River Delta. The delta supports the largest fishery in North America. It's home to drilling rigs and refineries, and harbors abundant wildlife. But a labyrinth of structures built to ease navigation, provide flood protection and secure access to oil and gas resources has carved the wetlands up like a jigsaw puzzle.

All this complex engineering has had an unintended effect: the region's wetlands are slowly drying up. As VOA's Rosanne Skirble tells us, experts say they'll continue to deteriorate unless a way can be found to restore a natural balance to this important, and vulnerable, ecosystem.

SKIRBLE: The hurricanes that swept across coastal Louisiana and bordering states last August left their mark on the marsh. The 8-meter storm surge from the Gulf of Mexico washed in salt water and lifted up mats of marsh grasses and folded them back over one another like an accordion. As he scoops out a sample of the muddy soil, coastal ecologist John Day says the mounting layers of peat, root matter and dense gray clay are what keep the Delta from sinking.

DAY: "This is a history of the last one hundred years of this site probably. And you see as it sinks, it has to build up. If it wasn't building up and the wetlands became more and more flooded, they would have turned into open water. But because they were growing and because we have this living root mat here — a real thick fibrous root mat — they grow up."

SKIRBLE: But coastal development and flood protection systems like levees and dams and canals are killing the wetlands at the rate of 65 square kilometers a year. Put another way, an area about the size of a football field is drying up every half hour.

Day says saving the wetlands begins with putting that water back. That's what the Fresh Water Diversion at Caernarvon has been doing. Day and his colleagues at Louisiana State University have been monitoring the project for over a decade.

DAY: "And we know that when that water flows in here, this is a very healthy area. Wetland loss stopped in this area. And, the wetland plants are very productive here. There is a big fishery here too."

SKIRBLE: Here's how it works: Water from the Mississippi is diverted through floodgates cut into the levee. The water runs down through culverts under a highway, into a canal and eventually into the marsh. On this day the floodgates — controlled from a station on top of the levee — are wide open.

DAY: "You can actually put a lot of water through here. You can put 8,000 cubic feet per second through this structure, and we've found that that stabilizes land loss for probably 500 square kilometers of marshlands over here. Fresh water compacts salt water. It provides nutrients, which makes the grasses grow more. It provides sediments which gives a stronger soil and all those things enhance the growth rate of the marshes."

SKIRBLE: Day would like dozens more such water diversions built along the river, but admits the process is slow. It took more than 25 years and considerable political and economic wrangling to get the Caernarvon project built and put into operation.

SKIRBLE: Another marsh restoration project of a different sort is located along the levee at the Gore sewage pumping station a few kilometers down the highway from Caernarvon.

This area — once covered by a dense cypress swamp — is largely a dead zone now of bare, lifeless tree trunks, laid waste by saltwater intrusion. Day says the wetland could be brought back if it were nourished with, of all things, treated sewage.

DAY: "It's treated for pathogens so that there is no bacteria and it is checked for toxic materials. So really you have fresh water with some levels of organic matter and nutrients. And if you put this out here that will fertilize this swamp and keep it healthy and this is an example of that."

SKIRBLE: Day says the idea might take a little getting used to, but as communities along the Gulf Coast consider how to rebuild the dozens of sewage treatment plants destroyed by last year's storms, the option looks more appealing. With a wave of his hand, Day gestures toward the only patch of swamp that remains because of freshwater effluent from the pump station and oxidation pond.

DAY: "You know you can get cypress seedlings this high. Just go out and plant them, and then they will grow. There is no problem there."

SKIRBLE: For decades Day has studied more than a dozen such projects. Day says the idea is to use effluent as a marsh-building resource instead of letting it flow back into the river. Marshes, he says, are natural barriers against storm surges. And he believes that more coastal communities must adopt strategies to protect themselves from the even more intense storms predicted for the future.

The U.S. space agency NASA finally launched twin satellites Cloudsat and Calipso from California on Friday. The launch had been subject to a long series of delays caused by a labor dispute, weather and some technical mishaps, but the liftoff Friday was flawless, with the two satellites heading for orbit on board the same rocket. Cloudsat and Calipso will help scientists study the role of clouds and aerosols in the atmosphere and how they affect weather and climate.

And speaking of satellites, it's time again for our Website of the Week, which this time is an online reference for all things aerospace.

SCOTT: "Our website is mainly an educational site that we try and answer questions that our visitors come and ask about different aspects of aerospace engineering, whether it be related to commercial aviation, military aircraft, space travel, careers in the industry and so on."

Jeff Scott is one of the eight aerospace professionals behind, an informative website featuring aircraft and spacecraft design, the popular "Ask a Rocket Scientist" feature, and a virtual museum of both military and civilian aircraft. In fact, the aircraft museum was how it all got started.

SCOTT: "And over time we started writing detailed descriptions of the aircraft. You know, their histories, what made them unique and how they worked. Then we started including technical details, such as their overall sizes and weights and all the different versions of that aircraft that were built and what missions they performed, and so on. And over time it's become a fairly large collection of information on military and commercial aircraft, helicopters and so on."

The "Ask a Rocket Scientist" section we mentioned a moment ago is one of the most popular features of Jeff Scott says they receive about 100 questions a week.

SCOTT: "We wish we could get to them all. But each week we try and pick one or two that are subjects that we feel are interesting enough to write about and interesting to our readers to learn about. And ... one of the things that's most interesting about doing this sort of thing is that oftentimes people will ask a question, something you've never thought about or maybe something you've always been curious about but never really had the time to go look into it in detail."

This week's question involves a nearly-forgotten U.S. Navy program from the 1950s to launch a satellite on a rocket fired from a fighter jet flying at high altitude.

The archive of questions and answers covers a lot of ground — or should we say, a lot of space and sky. Other recent ones were about deciphering the national markings on military aircraft, the Greek names for the planets, the variability of the speed of sound, and how jet engines work.

You can ask your own question, or read the answers and learn more about all kinds of flight at, or get the link from our site,

MUSIC: "Fly Me to the Moon" (Per Goldschmidt)

It's VOA's science and technology magazine, "Our World." I'm Art Chimes in Washington.

A new report from the prestigious U.S. National Research Council says America should act now to maintain leadership in particle physics.

SHAPIRO: "We came to the conclusion that this might be the most exciting moment in particle physics in a generation."

That's Harold Shapiro, former president of Princeton University and chairman of a special committee on the future of particle physics research.

Particle physics is perhaps the branch of science most remote from our everyday experience. It has to do with the study of subatomic particles and the origin of matter - knowledge that is without any obvious practical application but which is fundamental to understanding our universe.

It is also a field in which some of the most advanced work requires very large and very expensive machines that physicists call particle accelerators — atom smashers to the rest of us.

In the 1990s, the United States was poised to leap ahead with a project called the Superconducting Supercollider. But after construction had begun, Congress decided it was too expensive and cancelled the program.

Since them, some of the most advanced work in the field has been done outside the U.S. — in particular, at the European laboratory known as CERN, where they are building the Large Hadron Collider, which will be the world's most powerful accelerator.

After that, and still on the drawing boards, is a project called the International Linear Collider. No matter where the ILC is eventually built — and Shapiro's committee says the United States should mount a compelling bid to build it in America — the expensive field of high-energy physics will still be an international effort requiring international cooperation.

SHAPIRO: "Responsible public policy requires that we don't all duplicate all these experiments in various regions around the world, but that we work together to try to sort of internationally optimize the resources that are devoted to particle physics by countries around the world. Some of these facilities will be here. Some of those facilities will be elsewhere."

Scientists like to think there is value in pure research, but when they have to justify the cost, they try to make a field like particle physics sound a bit less theoretical. When I asked him why taxpayers should agree to pay for this kind of expensive science, Harold Shapiro explained how our technologically-advanced society and economy ultimately stand on a foundation that includes basic research.

SHAPIRO: "The vitality of this country - its economic vitality, its cultural vitality — is not won in a day. It's won in a generation. And in a generation, discoveries research, basic research is absolutely the central route to supporting the scientific enterprise. It will wither away on its own if all we do is pay attention to picking the fruits off the tree, rather than nourishing the tree. And the question is whether our generation, the generation now, really wants to prepare something that will be reaped for the next generation, like the generations before us did, or not."

Harold Shapiro led the Committee on Elementary Particle Physics, whose report was released on Wednesday.

Finally today, it was 15 years ago that a team of scientists built a giant greenhouse in the Sonoran Desert of the southwestern United States. Filled with plants and small farm animals, the structure was designed as a self-contained microcosm of the earth. It was called Biosphere 2 — a reference to our own biosphere here on Earth — and was imagined as a prototype for a human space colony. But as Rene Gutel reports, the project collapsed under the weight of scientific and manmade problems, although the participants remain proud of what they accomplished.

POYNTER: "The project was the poster child, if you will, for space exploration, for environmental and ecological research. It really did talk about hope for humanity and vision for the future."

GUTEL: Jane Poynter is one of the eight people who lived inside Biosphere 2 for two years. The idea was relatively simple. The Biospherians, as they were called, would bring nothing in and take nothing out. They would grow all their own food, and the facility would even be completely sealed from the outside air.

It was called a breakthrough experiment and received wide attention from the media, including television newscasts.

PETER JENNINGS (ABC-TV): "Tonight we put a fascinating look into our future on the American agenda. A look into the future through the eyes and thoughts of eight men and women who are about to enter a tiny, manmade world in the middle of the Arizona desert.

GUTEL: The eight researchers began their two-year journey on September 26, 1991. They were specialists in a variety of fields, including a medical doctor. Inside, the four men and four women each had their own living quarters. They rose early to tend to the plants and gardens, and feed the animals. They cooked their own meals, and kept records of the changes they observed in the plants and the atmosphere. Biospherian Linda Leigh says after the experiment began, they began to notice a problem.

LEIGH: "When we closed the door in the Biosphere the oxygen level was a little bit lower than the ambient - and the ambient being what we breathe right here outside - And after a period of months the carbon dioxide kept increasing inside and the oxygen was decreasing. So we not only had an atmosphere that was not very healthy for humans, because of the low oxygen and the high CO2, but we had a puzzle, we had a mystery."

GUTEL: The crew couldn't pinpoint the cause of the oxygen loss, but Biospherian Jane Poynter says they immediately began to suffer its effects.

POYNTER: "You feel incredibly lethargic. It's difficult to do anything. You couldn't complete a sentence without taking a breath. It was really quite dreadful."

GUTEL: The team made the controversial decision to add oxygen. But that decision came at a cost. Biosphere 2 was ridiculed in news reports.

NEWS BROADCASTS: "When it opened it was touted as a prototype for human colonies in space. It's going to be very difficult if they have the kind of trouble in space that they're having near Tucson." "Biosphere. Some charge it could bring an early end to the scientific project. The Tucson TV report reveals scientists learned the plants alone could not remove enough carbon dioxide from the indoor atmosphere."

GUTEL: In addition to the oxygen problems, the Biospherians struggled to grow enough food. And there were also personality conflicts. But they did last the full two years, re-emerging on September 26, 1993.

Jane Poynter says part of the problem was that the project was overhyped.

POYNTER: "I think a lot of people felt betrayed, to some degree, because, you know, we had said we're not going to take anything in! It's going to be materially closed. Well, of course, I mean that's really a rather ridiculous statement."

GUTEL: Linda Leigh agrees.

LEIGH: "There is our core group of people, the Biospherians and a few of the other people involved in the idea of the Biosphere, who are like a little army of people who were convinced that it was going to be absolutely perfect when we closed the door. It's silly in retrospect, but maybe we had to think that way in order to get it done."

GUTEL: After the experiment ended, scientists struggled to determine the cause of the oxygen loss. Part of the problem, they found, was that microbes in the soil absorbed oxygen faster than the plants could replace it. For a while, Columbia University used the Biosphere structure for environmental research, but in 2003, Columbia backed out. The experiment's original financial backer, Texas billionaire Ed Bass, has put the property up for sale. It hasn't been sold yet, but high-end real estate developers have expressed interest. For now, the greenhouse is open daily for public tours, a relic of an unrealized vision. For Our World, I'm Rene Gutel in Phoenix.

MUSIC: "Our World" theme

That's our show for this week. Drop us a line, let us know what you think. We're always happy to hear from you. If you've got a science question, and we answer it on the air we'll send you a special VOA gift as our way of saying thanks. The email is Or use our postal address -

Our World
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The show was edited by Rob Sivak. Eva Nenicka is our 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.