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MUSIC: "Our World" theme
Straight ahead on "Our World" ... Previewing the next space shuttle launch ... there may be such a thing as too clean ... and a new biography of DNA pioneer Francis Crick.
RIDLEY: "And what they say is, 'it has not escaped our notice that the specific pairing we postulate suggests how the hereditary material might work.' Now, it's the sort of great understatement of all time."
Those stories, middle age at 125, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
The U.S. space agency has set next Saturday, July 1, as the launch date for the space shuttle Discovery despite the misgivings of two senior NASA managers. They expressed concern that engineers still have not completely fixed the problem of foam insulation falling off the shuttle's external fuel tank during launch. Pieces of falling foam damaged the shuttle Columbia when it was launched in 2002, causing the spacecraft to break up as it was returning to Earth, killing all seven astronauts on board.
There has been one shuttle flight since then, and it, too, was plagued by what NASA calls "foam shedding." That mission, however, ended safely.
That was last July. Now, just days before the scheduled launch of Discovery, VOA science correspondent David McAlary is here in the studio to bring us up to date. ... Dave, why has it taken NASA almost a year to ready the shuttle for this flight?
McALARY: "Because essentially they have exhaustively gone over every square centimeter of foam that insulates this large tank to redesign areas to make sure that as little foam as possible comes off. So this has taken a long time, and they've been putting the tank through various tests to determine how it will react to the pressures of launch.
Q: To try to simulate the experience?
McALARY: "Right. But now they say, they've done as much as they can on earth, and they really need a flight to determine what they do from here."
Q: There was apparently, during what NASA calls the Flight Readiness Review, there was apparently a difference of opinion. Some of the managers at NASA were apparently a little bit uncertain about this.
McALARY: "Yes, and these were two important managers. One was the agency's chief safety officer [Bryan O'Connor] and the other was the agency's chief engineer [Chris Scolese]. Both said they would have preferred that the shuttle not fly yet, until further foam modifications were made. Other NASA officials say the crew is in no danger, even though some foam could still come off and even possibly hurt the shuttle. Once they get to space they're not in danger. The real danger's during liftoff and landing. Especially upon landing, when you build up all the heat, all the friction of the atmosphere. But in space, docked to the space station, even if there were some damage, the crew wouldn't be in danger. But they would not attempt to land if something happened to the orbiter. The crew would simply stay aboard the space station and wait for a rescue flight from Atlantis, one of the remaining orbiters."
Q: NASA has set an ambitious schedule of shuttle flights over the next several years. What's on the agenda? What will the astronauts be doing?
McALARY: "Well the prime mission is to complete the construction of the space station, which has been held up by this long hiatus in shuttle flights. And there is some thought that one shuttle flight might be dedicated to restoring the Hubble Space Telescope yet one more time, although no final decision has been made on that."
Q: A lot of astronomers hoping that will happen. NASA plans to retire the shuttle fleet by 2010. That's not that far off. What happens after that?
McALARY: "There's going to be a period of years - it cold be anywhere from two to four, depending on how things proceed - where we have nothing that could bring humans to space. President Bush is adamant about shutting down the space shuttle program and moving on to the new exploration program for the moon and eventually Mars at some point. And for that, a new crew vehicle will be necessary. So they have determined they're going to finish construction of the space station by 2010 and try to get that new crew vehicle for the later missions to go out of low earth orbit by, hopefully, 2013, possibly 2014."
Q: And in between then, we'll depend on Russian spacecraft to bring astronauts to and from the space station?
McALARY: "Yes, of course. And of course they have saved the international space station program with their hearty Soyuz capability. It's a real rugged spacecraft."
Q: Relatively low tech, but it gets the job done. VOA science correspondent David McAlary. Thanks very much for joining us, Dave.
McALARY: "Pleasure to be here, Art."
The human body is an amazing machine, but it is notably poor at growing spare parts. If you lose a finger, an eye or a leg, that's it. You can't grow another one. But researchers are starting to look seriously at whether such regeneration, as it's called, might be possible. After all, salamanders can re-grow legs.
The Pentagon's advanced research agency DARPA has started funding scientists investigating the problem, amid a stream of soldiers returning from Afghanistan and Iraq minus arms and legs.
We appear to be a long way off from figuring out how to regrow a limb, so researchers are starting small. At the House Ear Institute in Los Angeles, researchers reported some promising, if preliminary developments in this week's issue of the journal "Nature."
Inside our ears are tiny hairs that convert the vibrations of sound into neural impulses. Damage the hairs, and hearing can be lost. Researcher Neil Segil says that some animals have the ability to re-grow those hairs.
SEGIL: "In birds, for instance, that are deafened, they have full functional recovery in a matter of a couple of weeks. However in mammals, like mice and humans, when those cells are lost - and they're extremely sensitive to all kinds of environmental trauma, like noise and many kinds of antibiotics - they're gone for good."
The sensory hairs can re-grow with the aid of what are called supporting cells, located nearby.
In a "Nature" podcast, Segil explained that in mice, they found some of those supporting cells retain the ability to turn into hair cells.
SEGIL: "There is a dramatic change between the newborns and the two-week olds. In the newborns, a large percentage of those supporting cells can begin to divide and then transdifferentiate into hair cells. Two weeks later, very few of those cells can begin to divide, and yet many of those cells can still differentiate into hair cells."
Their research is very preliminary, and a long way from curing deafness, but Neil Segil says they have identified a gene that blocks the ability of new hair cells to grow. That's a small step toward understanding a process that might one day permit us to reverse at least some hearing loss.
Scientists have wondered why people in Western countries - where we're hung up on cleanliness and sanitation - get more asthma, allergies and auto-immune diseases than people from countries where hygiene is a problem. As we hear from health reporter Rose Hoban, it may be that we're TOO clean.
HOBAN: So William Parker, a researcher from Duke University in North Carolina collected wild rats to compare their immune systems with those of animals raised in clean, laboratory conditions.
PARKER: "There's a really good chance that parasites and other infections change the immune system in a way that you don't have a propensity or a tendency to get allergies or autoimmune disease"
HOBAN: The wild rats — not surprisingly — were riddled with diseases and parasites. But Parke found, surprisingly, that they didn't react to common allergens the way the lab rats did.
PARKER: "Our wild rats their immune system is having a lot of things to worry about and it doesn't sweat the little things. So for example, a little pollen grain that's coming by, it's going to just ignore that, whereas the person who's living in a very clean environment or the lab rat, might be very concerned about a pollen grain and in fact might become allergic against it."
HOBAN: This finding is in line with a theory that says people from countries where there is widespread use of antiseptics end up developing more allergies than people from places with less sanitary living conditions. Parker says his findings also suggests people's immune systems need to be challenged more by dirt and disease during childhood. But he says that's difficult to test in humans.
PARKER: "You know a lot of people say if you let your kids get dirty they won't get allergies and autoimmune diseases. But doctors don't recommend that because we live in such crowded conditions that we get other diseases.
HOBAN: Parker is collecting more wild rats for further study. I'm Rose Hoban.
Time again for our Website of the Week, when we showcase interesting and innovative online destinations.
This week, it's an Internet site for people who want to learn more about ocean life and the threats it faces.
LAWRENCE: "MarineBio.org is a site that was developed to showcase marine life and remove some of the mysteries surrounding the ocean, to inspire people to appreciate and protect it. And it's targeted to a broad audience from young kids under the age of 12 to students at all academic levels, as well as scientists and policymakers."
Joni Lawrence is the editor of MarineBio.org, which features a wealth of information about the oceans and the creatures that live there. She says the cornerstone of the site is its collection of individual pages on marine species — 250 now, with more being added all the time. The latest additions are a number of different penguin species, but the most popular include sharks, dolphins, whales and squid.
LAWRENCE: "On every page we strive to include really beautiful photographs, and then we go into describing biological information like habitat, feeding behavior, life history or ecology. And then at the end, we include comments about each species - whether it's dangerous to humans, whether it's fished for human consumption, and whether it's threatened or endangered."
There are also sections on how climate change threatens the ocean environment and on careers in marine biology. Joni Lawrence also notes the interactive nature of MarineBio.org, especially a feature called the Plankton Forums — a popular online bulletin board:
LAWRENCE: "In the forums we have young people, high school students, who are very involved in the study of marine biology already, and then we also have marine biologists, so those two groups have the opportunity and do interact very often. So it's great for the young people to have access to marine biologists willing to answer their questions about how to develop their careers or questions about individual species or marine issues. And we also often talk about conservation issues in there as well. And we find that everybody from the scientists to the young people are all very passionate about the issues."
Information and passionate conversations about the ocean world on our Website of the Week, MarineBio.org, or get the link from our site, voanews.com/ourworld.
MUSIC: "By the Beautiful Sea" from the 1942 MGM film, For Me and My Gal
And you're listening to VOA's science and technology magazine, Our World. I'm Art Chimes in Washington.
Out this month is a new biography of Francis Crick, the co-discoverer — with James Watson — of the double helix structure of DNA, the biochemical basis of human heredity. I spoke with author Matt Ridley, who rates Crick as one of the greatest scientists of all time, right up there with Galileo and Einstein.
RIDLEY: "He rates that big in my view because of the significance of the discoveries that he made and that he was involved in making. In other words, the revolution in biology that came about because of the discovery and deciphering of the genetic code in the 1950s and 1960s was surprising, far-reaching, transcendent and every bit as important as relativity and gravity and so on. Francis Crick dominated that revolution just as Darwin dominated the natural selection revolution."
Q: Crick and Watson - it seems like one word — and for years they're the "co-discoverers of the double helix" — but they each brought something different and unique to the collaboration that worked together, more than the sum of its parts.
RIDLEY: "Crick and Watson had a brilliant collaboration, partly because they brought different strengths. Watson was a biologist, he knew the genetics very well, he knew the whole subject from the biological point of view. Crick was a physicist, he knew how to interpret X-ray crystalographs, which was a crucial insight. But they had something in common, too, which was they liked talking about science. They liked arguing, they liked debating. They liked interrogating. They weren't afraid of speculating."
Q So it was not just the scientific background in different disciplines, but also the personalities that meshed that way?
RIDLEY: "Yes and they brought out the ambitious, competitive streak in each other in a remarkable way. It really was an extraordinary meeting of minds when they met. And then, for the rest of his career, Crick had this pattern, that he was always working with one other favored colleague who was a close friend, who he argued with morning, noon and night in his office. There was a gap in the '70s, when he didn't have anyone to talk to, and he's visibly at a loss during that period in some ways."
Q In the book you talk about the process by which they eventually came to the double helix structure. There was not really a eureka moment really in the way you would see in the movie — I guess it would have to be a buddy movie of the two of them.
RIDLEY: "Yes, it was a gradual piecing together. But I think there were two eureka moments. One was when Crick realized that the chains must run in opposite directions, and that solved the problem of how to fit the base pairs into 360 degrees rather than 180, then suddenly the whole general shape of the molecule fell into [place]. The other eureka moment was when Watson realized that the base pairs fitted together so that adenine and thymine together were exactly the same shape as guanine and cytosine together, and therefore they could substitute for each other anywhere in the structure, but one strand would always predict the other strand."
Q: So the April 25, 1953, edition of "Nature" comes out, it's got scarcely more than one page for the Crick and Watson article. I think somebody knowing the momentous nature of what was to come would feel a little disappointed.
RIDLEY: "This paper, as you say, a single page in Nature in April 1953 with only one sentence that hints at the significance of this. And what they say is, 'it has not escaped our notice that the specific pairing we postulate suggests how the hereditary materials might work.' Now, it's the sort of great understatement of all time. There was a big argument about even having that one sentence. Crick wanted to say a lot more; Watson would only agree to that very enigmatic sentence because he thought that it was too speculative, it wasn't yet certain, they might have got it wrong. It was a beautiful structure, but what if it wasn't correct. He was very cautious at that moment."
Francis Crick was 36 years old when Nature published Crick and Watson's double helix paper. Crick continued doing science for another half-century, almost until he died two years ago. Author Matt Ridley says it's unfortunate that Crick's later work is not well known.
RIDLEY: "My argument is that the double helix was the beginning of Crick's career, not the peak, and that his great years were the deciphering of the genetic code — well, not the deciphering, but the working out of what the code was and what it did — in the years between 1953 and 1966. In the late '80s, he then moved on to trying to understand how the brain works. What he wanted to do was pin down the seat of consciousness in the brain. He didn't succeed in that, but he did both help make the study of consciousness respectable and set out a sort of framework for how to think about consciousness in the brain, which a lot of people now follow. So those were his achievements after 1953. It's the genetic code work that I'm particularly drawing attention to because it's overshadowed by the double helix. Double helix was one blinding flash of luck, almost. Then there were 15 years of real genious and real understanding and real insight and brilliant experiments, extraordinary predictions, etc., that came after that, which was when he earned his reputation for being a great scientist."
Matt Ridley's book, Francis Crick, Discoverer of the Genetic Code, is just out in the U.S., published by Harper Collins.
Finally this week, South Dakota's Reptile Gardens claims to have the world's largest collection of reptiles ... including a Galapagos tortoise named Methuselah, who turned 125 this month. Jim Kent was at his birthday party to learn about the animal's appeal to visitors and scientists.
KENT: 1881. The world's first electric train began operating near Berlin… Louis Pasteur Develops the first artificially-produced vaccine against anthrax. And just off the coast of Ecuador, a tortoise — later named Methuselah — was born on the Galapagos Islands.
BROCKELSBY: "Methuselah is our giant Galapagos tortoise. It's lived here at the Reptile Gardens since the early '50s. And the second weekend in June every year we celebrate his birthday. It just so happens that this weekend is a big one, he's a century and a quarter...he's 125 years old."
KENT: John Brockelsby, in contrast, is a half-century or so old. He was just three when his father brought the giant tortoise to Reptile Gardens, the South Dakota tourist attraction he'd opened in the 1930s. Brockelsby, now spokesman for the family-run operation, says Methuselah's arrival was a big deal.
BROCKELSBY: "They are some at other zoos, but we're.... I think, maybe the only where we allow people to have contact with them, they can pet them and have their picture taken with them and things like that."
KENT: Okay. So, he's huge, he's friendly, and he's old. Is that really worth getting excited about? According to Bryan Milstead of the Charles Darwin Research Station on Galapagos, the answer is a resounding "yes."
MILSTEAD: "Well, I think it's clearly an impressive feat for any vertebrate tobe this age. This animal has probably been settling nicely into a later middle age. That it's 125 years old is impressive. But more than likely, 50 or 75 years from now, that tortoise will be celebrating more birthdays there in South Dakota. It's an interesting anomaly that an animal can live to be that age."
KENT: He says Methusela's birthday is also a chance to recognize his species' contribution to science.
MILSTEAD: "They're also important due to the importance that they had in the development of the theory of evolution by natural selection. The variation among these and the differences among islands inspired Charles Darwin in some of his initial thoughts."
KENT: The fact that tortoises have been on the planet for about 100 million years, adds Dr. Milstead, combined with their astounding longevity, makes them individual scientific treasures that can actually be shared by multiple generations. No one has documented the life span of Galapagos tortoises in the wild, but we do know that Methusela is not unique. Louise Martin, spokeswoman for the Australia Zoo, notes that Harriet, their Galapagos tortoise, was originally taken from the Islands by Charles Darwin himself. She will turn 176 this Fall.
[After Jim Kent filed this report we learned that Harriet died at the Australia Zoo, apparently after suffering a heart attack.]
MARTIN: "It's just fascinating. It really does make you realize just how special these...I mean. I'm there with the oldest living animal in the whole world."
KENT: The secret to the longevity of the Galapagos tortoise, explains John Brockelsby, is their very slow metabolism, an excellent diet, and something he says humans could take a lesson from.
BROCKELSBY: "They're our gentle giants. And I think that the fact that there's no viciousness about them. He doesn't get excited about anything. He moves in slow motion, he has no fat or cholesterol in his diet and he's completely non-aggressive. So, I always tell my human friends, you know if we could follow those things we could maybe add 20 years to our lifespan."
KENT: Nineteen year old Lindsay Drake is trying to follow that advice. The veterinary student works with Methuselah on a daily basis, and says meeting a Galapagos tortoise up-close-and-personal is something everyone should experience.
DRAKE: "It's sort of like, you know, seeing a dinosaur. We can just see the fossils of a dinosaur, but we can see these animals alive and well."
KENT: Alive and well is just what they are. Galapagos tortoises have been protected by the Ecuadorian government since 1959. Their once dwindling local population is now estimated at 20,000. There's no official count of how many of these giant creatures are in captivity in the world's zoos but, given their lifespan, they should be around long enough for most people to catch a glimpse of a living piece of history. I'm Jim Kent, with Methuselah, as he enjoys his birthday watermelon at Reptile Gardens in Rapid City, South Dakota.
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Rob Sivak edited the show. Eva Nenicka is our 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.