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Our World — 28 July 2007


MUSIC: "Our World" theme

Straight ahead on "Our World" ... Mars rovers wait out dust storms on the Red Planet ... using math to fight cancer ... and a listener asks about birds and dinosaurs

CONRAD: "Tyrannosaurus rex is actually more closely related to hummingbirds than to triceratops or apatosaurus. If you look at a bird foot, it looks very much like the foot of tyrannosaurus rex."

Like T. rex, but much smaller! Those stories, studying climate change in Greenland, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

At the U.S. space agency NASA, they're keeping a close eye on the weather. The Martian weather, that is. Severe dust storms in the upper atmosphere are screening out 99 percent of the sunlight reaching the surface, where the Mars exploration vehicles Spirit and Opportunity are not getting enough power from their solar cells.

We checked in with rover program manager John Callas for a weather update.

CALLAS: "Right now as of today, the weather is actually getting worse for Spirit and has been fairly stable for Opportunity. Opportunity had experienced some really bad weather last week, which had given us some concerns. It's moderated a little bit, but now the weather is getting worse for Spirit."

The rovers have halted operations, using what little power they have just to stay warm. The storms blew up just as Opportunity was poised to roll down into the Victoria crater to explore that particular bit of Martian geology. It's now just 40 meters from the crater's edge.

CALLAS: "As soon as the weather improves sufficiently, and we have confidence that the next several days will be, you know, good weather, then we'll start the path into the crater. Had we been in the crater, it wouldn't have made any difference in terms of the vehicle's response to the weather. So it isn't like we would have been in a worse situation had we been inside the crater or anything like that. It would have been pretty much the same."

NASA's John Callas. Another robotic explorer is about to be launched to Mars. The Phoenix lander will blast into space on an unmanned rocket as early as this Friday (August 3). About 10 months later it is due to land in the Martian arctic where it will use its mechanical arm to dig under the surface, where scientists think there may be water ice.

Satellites orbiting Mars have sent back great data, but Phoenix scientist Bobby Fogel says that sometimes you just have to be there.

FOGEL: "It's going to analyze the water. It's going to get its chemical composition, its physical properties, and try to tell us something about the history of water on Mars and potential habitability for microbes on Mars. Now remember, we have other assets at Mars that are remote sensing assets. But as good as remote sensing assets are, sometimes there's nothing that replaces actually going down and doing an experiment with the actual material."

The Phoenix spacecraft, incidentally, was more-or-less cobbled together from pieces left over from other missions. Sort of a high-tech recycling program, I guess.

NASA had some unexpected bad news this week. First, a computer set to be sent to the space station on a shuttle flight next month was apparently sabotaged by an employee of a subcontractor.

Then, Friday, a NASA committee on astronaut health said there had been two incidents where astronauts were allowed to fly despite drinking enough alcohol before the flight that other astronauts or medical personnel raised concerns about flight safety. NASA did not identify the astronauts or the flights involved.

The committee was appointed in February after a bizarre incident in which astronaut Lisa Nowak drove halfway across the country to confront a woman she allegedly considered a romantic rival for another astronaut.

After five months of work, the NASA committee recommendations include mental health screening be added to astronauts' annual medical exam as well as a stricter alcohol policy.


Public smoking bans are becoming a lot more common in the United States and many other countries, too. But how effective are they in protecting the health of non-smokers? As we hear from reporter Rose Hoban, there hasn't been much data measuring the health impact of these new laws — until now.

HOBAN: That data comes from a study of cotinine, an extremely accurate marker for the presence of tobacco that's found in saliva. Researchers from the New York State Department of Health had the opportunity to measure the amount of cotinine in people both before and after implementation of a new statewide law banning smoking in public places. Ursula Bauer heads the state's tobacco control program.

BAUER: "When people inhale smoke that contains nicotine — they can do that either by actively smoking a cigarette or by breathing the smoke of someone else's cigarette that's in the air, or actually, if people chew on a piece of nicotine gum or use smokeless tobacco — their body will break down that nicotine that they either inhaled or ingested, and one of the byproducts of the nicotine is cotinine."

HOBAN: Health Department workers collected saliva samples from close to 1,600 non-smokers from around the state in the months after the ban took effect. They found the levels of cotinine had dropped by almost half.

BAUER: "About 86 percent of workers were already working in smoke-free workplaces. And that didn't really change after the law went into effect. But what did change was the smoking that occurred in restaurants and bars, bingo facilities, bowling facilities. T hose exposures went way down, because this law addressed those places."

HOBAN: Bauer says one would think these leisure-place exposures would be insignificant. Nonetheless, she says cotinine from these casual encounters with second-hand smoke were measurable and significant.

BAUER: "And I think the take-home message for other states and other nations is you really need to implement a comprehensive law if you want to have such dramatic reductions in second-hand smoke exposure. And of course we expect these reductions to translate into actual health improvements over time."

HOBAN: Bauer says the health department will continue studying those health effects in the coming years. Her data was published in the Morbidity and Mortality Weekly Report, a publication of the U S Centers for Disease Control and Prevention. I'm Rose Hoban.

What do zebras, bacteria, and cancer have in common? They all can evolve in response to pressures in their environment. This simple biological fact inspired researchers from the University of California, Irvine, to study cancer in a new light. They used mathematics, rather than biology, to test a theory that that tumors change their mutation rate "intentionally" as they grow, in order to grow as quickly as possible. This research was published in the Royal Society's journal Interface, and VOA's Adriana Salerno has details

SALERNO: For some time now, laboratory scientists have known that cancer cells behave very differently from normal cells, constantly changing their genetic makeup, as Natalia Komarova explains.

KOMAROVA: "If you look at a normal human cell, it contains 23 pairs of chromosomes. But if you look at the cancer cell it's a complete mess: some chromosomes are present only in one copy, some are missing, and some are present in five or six or ten copies. So this phenomenon is called genetic instability. Basically it means that as cancer cells divide they lose or gain genetic material, they change all the time."

SALERNO: Komarova notes that everyone who studies cancer knows that genetic instability - and the mutations it causes - are important for cancer cells: cancer couldn't spread without it. It's not so clear why this mutation rate slows down in later stages of the tumor.

KOMAROVA: "So this is experimental observation and nobody really knows why it's there, and whether it's even important for cancer, maybe it's just a side-effect of cancer."

SALERNO: To try to understand the process, Komarova and her colleagues turned to optimal control theory, a branch of mathematics used to determine the most efficient pathways, and they applied it to the mystery of cancer growth.

KOMAROVA: "And it turns out that it's advantageous for cancer to keep a high level of genetic instability at first and then turn it down later on. So it kind of pays off to change all the time, to lose chromosomes, to gain chromosomes, at the beginning; and then stop doing this and remain at the same level for the rest of the natural history of a tumor."

SALERNO: Natalia Komarova is a mathematician, not a medical researcher. But Dr. Andrew Pierce, of the University of Kentucky College of Medicine, says her results make sense because they parallel what many living organisms do to thrive in their environment. He points to the way bacteria develop resistance against an antibiotic.

PIERCE: "And so the idea is 'OK, my current genetic solution isn't a very good solution anymore, so let's mix it up and try a bunch of random stuff and see if something can be come up with randomly that just happens to work better.' This is the standard way in which evolution is thought to work. And after the solution has been established, now the stress from the environment has been relieved."

SALERNO: Knowing the reason for a tumor's genetic instability, mathematician Komarova says, might affect the development of cancer treatment strategies.

KOMAROVA: "So for instance chemotherapy is very mutagenic: it makes a tumor mutate even more. Other types of treatment, like small molecule inhibitors, are not mutagenic at all, they're not toxic, and they don't make cells mutate more than they do."

SALERNO: Although her research is not at that point yet, Komarova says she would like to incorporate treatments and their mutagenic properties into her model.

University of California mathematician Natalia Komarova hopes that her research will give the medical community food for thought during their quest for new approaches to fighting cancer. I'm Adriana Salerno.

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

This time it's a resource for farmers who want to protect their crops, consumers who worry about chemicals in the environment, or anyone interested in pesticides.

STONE: "The National Pesticide Information [Center] website is a service that provides science-based and objective, unbiased information to the public on pesticides and pesticide-related issues."

Dave Stone says the National Pesticide Information Center — npic.orst.edu — started out as a telephone information service — which it still maintains — and later migrated to the Web. It's a joint project of the federal Environmental Protection Agency and Oregon State University, where Stone is an assistant professor in Environmental and Molecular Toxicology.

He acknowledges that pesticides are controversial, which is why the National Pesticide Information Center aims to provide unbiased information.

STONE: "We only pull information that we put on our website from peer-reviewed articles, from government agencies, from cooperative agricultural extension sites. So we are pulling information that gets vetted through research and a lot of agency oversight."

Stone says the site is mainly used by the public, trying to sort out what pesticides would best suit their needs and how to use them safely. But researchers and government regulators also find useful information here. And because many of the same pesticide ingredients are used worldwide, the National Pesticide Information Center really has a global reach, with India and China now among the top five countries where users of the site are located.

STONE: "Pesticides are clearly an international industry, and there are a lot of developing countries that experience a lot of agricultural loss and public health disease from pests that can be mitigated through pesticides. But the labeling of pesticides, the specific country regulations, how they're distributed and shipped and used is just a real hodgepodge, but the same active ingredients do get used in many of the countries."

The National Pesticide Information Center at npic.orst.edu, or get the link from our site, voanews.com/ourworld.

(The NPIC is also assisting users by phone at 1-800-858-7378 and by email at npic@ace.orst.edu.)

MUSIC: Sax Gordon - "Big Hunt"

We try to keep the bugs out of VOA's science and technology magazine, Our World. I'm Art Chimes in Washington.

Time again to dip into the Our World listener mailbag for an answer to a science question sent in this week by Uchenna Ezeani of Jos City, Plateau State in Nigeria, who wants to know about the link between today's birds and dinosaurs.

For the answer we turned to Jack Conrad at the American Museum of Natural History in New York, world-famous for its research on dinosaurs and its galleries full of dinosaur skeletons. Conrad said modern research has confirmed a very close link.

CONRAD: "Birds are dinosaurs, but not all dinosaurs are birds. It's kind of the same thing as saying whales are mammals, but not all mammals are whales."

Today, scientists use DNA to classify species and determine what's related to what. They can't do that with dinosaurs, though, because — no matter what you've seen in the movies — DNA from the dinosaurs that died out 65 million years ago has not survived. So instead, they use traditional methods of classification, comparing anatomical structures. And Jack Conrad says that's where the similarities between today's birds and the ancient dinosaurs become obvious.

CONRAD: "If you're familiar with something like Triceratops or Apatosaurus, Tyrannosaurus rex is actually more closely related to hummingbirds than to Triceratops or Apatosaurus. And some of the things you can look at and actually see there are the shape of the neck. Theropod dinosaurs — meat-eating dinosaurs — have this elongate, S-shape neck that you also see in birds. They also have three functional toes on their feet, and you see that in many birds. If you look at a bird foot, it looks very much like the foot of Tyrannosaurus rex."

Conrad also points out that, like many dinosaurs, birds have hollow bones.

Although the theory of birds being an evolutionary cousin of dinosaurs has been around for a long time, it's really become mainstream science only in the past 10-15 years as more dinosaur fossils have turned up and the pieces of the evolutionary puzzle have come together.

CONRAD: "We found so many links between something like Tyrannosaurus and then something like any kind of modern bird over the last 15 years that the story is very complete at this point. We have a pretty good understanding of the story."

There are still a few skeptics, but by now it's become generally accepted by paleontologists that there is, in effect, a straight evolutionary line between the fearsome Tyrannosaurus rex, a six-ton behemoth, and the little songbird outside your kitchen window.

CONRAD: "At this point you could suggest without being laughed at (laughs) that at least baby Tyrannosaurus rex would have had feathers, a feathery covering."

Obviously it's a long evolutionary path from the dinosaurs that died out 65 million ago to today's birds, and it hasn't stopped yet.

CONRAD: "The evolutionary process is continuing in all organisms, as far as we know. Birds continue to evolve. If we could look into the future 5,000 years or 50,000 years, we would probably see new species of birds that don't occur right now. Evolution is a continuing process, and it will continue until there is no more life."

Paleontologist Jack Conrad of the American Museum of Natural History in New York. Thanks to Uchenna Ezeani in Jos, Nigeria, for sending in that great question. We'll be sending out a special VOA gift as our way of saying thanks. If you've got a science question, please send it in. If we answer it on the air we'll send you a gift, too. Our email is ourworld@voanews.com, or listen for the postal address at the end of the show.

Scientists studying climate had a much tougher time of it before the space age. Satellites have dramatically improved the quality and quantity of data that climate scientists have to work with. But there's no substitute for data gathered here on Earth. The remote island of Greenland provides a unique laboratory to study the impact of global warming, as VOA's Kane Farabaugh found.

FARABAUGH: Eighty-Five percent of Greenland, the world's largest island, is covered in a thick sheet of snow-covered ice. Greenland is also home to 10 percent of the total ice mass in the world and is one of the fastest warming locations on the planet. The average temperature is two degrees Celsius warmer than it was a decade ago.

If continued warming causes most of Greenland's ice to melt, sea levels will rise roughly six meters. Scientists looking at satellites believe southern Greenland is currently losing about 104 cubic kilometers of ice per year.

These are some of the statistics that have placed Greenland at the center of the global warming debate. It is also the reason University of Copenhagen professor Jorgen Steffensen is preparing for another summer on Greenland's vast ice sheet.

Steffensen studies cross sections of the packed ice — called ice cores — he gathers from drilling deep inside that ice sheet.

STEFFENSEN: "So whatever falls as snow on the ice cap never goes away. It just piles up. And therefore, the ice cap, the massive ice you have covering Greenland, is actually beautiful layer cake of snowfall upon snowfall nicely piled up over the eons."

FARABAUGH: Summit Camp is the tallest point in Greenland. It sits on top of 3,300 meters of ice. It is 400 kilometers from the nearest point of land. And it is one of several scientifically important locations where ice core samples are gathered.

It is a barren, frozen expanse. Small buildings, wire cables and tall wind fans dot the otherwise white landscape. Despite the harsh living arrangements and remote location, scientists like University of California professor Roger Bales take advantage of the conditions to gather data.

It is data that will help other scientists — like Steffensen — understand the evidence in the ice core samples.

BALES: "This is a very clean station. As you know, there's pollution in cities but there's also global pollution, so we come here, to one of the cleanest places in the Northern Hemisphere, to really understand what's happening globally."

FARABAUGH: What has happened globally over time is that the temperature is rising. Summit ice core samples give scientists an idea of how fast the ice melted during certain periods and how much carbon and gas was in the atmosphere when the snow fell. These are important measurements to determine to what extent so-called greenhouse gases contribute to global warming.

It might be hard to feel that temperature change standing in sub zero temperatures in one of the coldest places on earth. But almost every scientist who works here has come to the same conclusion, either by evidence gathered in the ice, or by data collected by experts on the atmosphere like Greg Huey.

HUEY: "The concept of global warming, it's not controversial in the scientific community. It's here. People might argue about how fast it is. They might argue about what steps to take but no one argues that it has to be [caused by] greenhouse gas emissions and the planet is warming, and unless we want to live in a very different climate for our children and grandchildren, we're going to have to do something about the carbon in the atmosphere."

FARABAUGH: The debate over global warming is not whether or not it's occurring, but rather who — or what — is causing it. Steffensen admits factual scientific evidence in that arena is hard to come by.

STEFFENSEN: "Because the climate system is so full of variation, natural variation, that to filter out whether this present warming is a natural variation or is man-made — that's impossible. But if there is a very strong correlation between our emissions and the [global] heating we are seeing today."

FARABAUGH: Much of the research being conducted in Greenland today helps provide sound, scientific evidence to lawmakers and leaders around the world.

BALES: "We want people to know that the atmosphere is changing and that we have these global atmospheric measurements and the evidence is solid for that. And it provides I think, a sound basis for decision makers on which to base mitigation measures."

FARABAUGH: Some of those measures include a concerted effort to legislate a reduction in carbon emissions worldwide. That is a long-term solution that could bring a balance to Earth's climate crisis.

But what scientists who work in Greenland and around the world fear most is a more rapid climate change fueled by current carbon emissions that could lead to untold devastation. Kane Farabaugh, VOA News, Kangerlussuak, Greenland.

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 ourworld@voanews.com. Or use the postal address —

Our World
Voice of America
Washington, DC 20237 USA

Faith Lapidus edited the program. Eva Nenicka is the 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.

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