MUSIC: "Our World" theme
Straight ahead on "Our World" ... an ice shelf at the bottom of the world hangs by a thread... one of Saturn's moons has the ingredients for life... and flexible computer chips give surgeons a revolutionary new tool...
ROGERS: "We're putting electronics and sensors onto latex gloves so that the tips of the fingers in the glove provide a sensing capability for measuring blood oxygen content, blood pH, temperature, and so on."
Those stories, concentrating the power of the sun, and more. I'm Faith Lapidus, sitting in this week for Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
Last week, we talked about the thinning of the Arctic icecap. This week, we turn our attention to the bottom of the earth — the frigid expanse of Antarctica... where the ice is not thinning so much as disintegrating. Satellite images in recent weeks show that a large chunk of an Antarctic ice shelf has collapsed into the sea. As Rosanne Skirble reports, it is a sign of rapid climate change in a region that has experienced the greatest temperature increases on earth.
SKIRBLE: The Wilkins Ice Shelf is a large and thick plate of ice on the southwest Antarctic Peninsula. It is one of a string of ice shelves that has collapsed in the region over the last thirty years.
Ted Scambos is a glaciologist with the National Snow and Ice Data Center at the University of Colorado, Boulder. He says there was a curious pattern in the Wilkins collapse.
SCAMBOS: "The first iceberg that broke off was perfectly normal, but behind it this area began to slice off long chunks, sort of like long slices of bread basically off of a loaf, so tall and narrow that they actually topple over into the water and this is really unusual."
SKIRBLE: Scambos says this indicates that the ice shelf is in retreat. He says the shelf — which floats on the ocean but is attached to land — could break up entirely within a few years because of warming in the Antarctic Peninsula.
SCAMBOS: "That pattern is pretty clearly related to global warming and the effects that is having in the Antarctic air circulation pattern."
SKIRBLE: The collapse of some 400 square kilometers from the 14,000 square kilometer ice sheet won't have any immediate impact. But, Scambos says, understanding the process is key to being able to predict how sea level will change in the future.
SCAMBOS: "These ice shelves that fringe Antarctica actually act to hold back some of the ice that is on the continent and slow down glaciers that are flowing into the ocean. There is a balance of forces between ice wanting to flow off of this large mound of ice that is Antarctica and these ice plates that are fringing it are obstructing it and therefore resisting the flow."
SKIRBLE: With Antarctic summer coming to a close, Scambos doesn't expect that Wilkins will collapse any further this season. Nonetheless, scientists will continue to monitor the threatened ice shelf.
SCAMBOS: "The point is that we're seeing this pattern march southward, and we want to try to turn around the effects of greenhouse gases over the next two decades before we do have to worry about significant amounts of sea level rise from both Greenland and Antarctica."
SKIRBLE: The National Snow and Ice Data Center studies both polar regions. Scambos says while the arctic is showing more effects from global warming, the potential for sea level rise from Antarctic melts is far greater. I'm Rosanne Skirble.
On Wednesday, two weeks after NASA's Cassini space probe flew past one of Saturn's moons, Enceladus, skimming just 50 kilometers above the surface, scientists released their preliminary findings, including their view on whether Enceladus might harbor some form of life. They also discussed the composition of an icy plume of water vapor spewing from the surface.
Hunter Waite of the Southwest Research Institute in Texas is the principal investigator for the Ion and Neutral Mass Spectrometer, one of Cassini's scientific instruments. He described the plume that the spacecraft passed through.
HUNTER: "The line I used earlier was that it's carbonated water with essence of natural gas. Water vapor was the major constitutent. There was methane present. There was carbon dioxide. There was carbon monoxide. There were simple organics and there were more complex organics. So those are the constituents we saw."
Of course, while water and organic materials are necessary for life as we know it, their presence doesn't necessarily mean there is life.
Heat is the other necessity for life, and as icy as Enceladus is — minus 180 degrees C. or so — temperature measurements from Cassini show at least one area that is much warmer. The principal investigator for the Composite Infrared Spectrometer, John Spencer, says they measured a surface temperature of a relatively toasty minus-93 degrees C.
SPENCER: "We know it's going to be even warmer below that, and it's not out of the bounds of possibility that somewhere down below we're getting temperatures up approaching the temperature of liquid water. Whatever is producing this heat on the surface is going to be producing even more heat underneath."
Larry Esposito, another scientist working on Cassini, concluded that while the ingredients may be present, it is still not possible to say whether Saturn's moon Enceladus actually is home to any life as we know it.
ESPOSITO: "We see on Enceladus the three basic requirements for the origin of life. We see water, although it may not be liquid. We see organic compounds detected by the Ion and Neutral Mass Spectrometer. And we also have a source of heat, indicated by the Composite Infrared Spectrometer. These three basic ingredients provide a minimum for the origin of life. Now we don't yet see, nor can we tell or state whether the interior of Enceladus contains liquid water, and if that water might be a habitat for life."
The Cassini science team is looking ahead to future fly-bys, when they'll have more opportunities to check out Enceladus. The next chance is in August, but in the meantime, if you'ld like to see some of the images and dig deeper into the latest discovery from Saturn's moons, NASA has lots of spectacular images and some pretty cool animation on the Cassini website. And we'll have a link on our site, voanews.com/ourworld.
The era of solid-state electronics, when transistors replaced vacuum tubes, is just over a half-century old. Today, millions of transistors can be etched onto silicon to make integrated circuits that power computers, mobile phones, and countless other devices.
But what if you could make those computer chips in another form that was flexible and bendable, instead of rigid and fragile?
That's what a team of material scientists at universities in the United States, South Korea and Singapore wondered. And in a paper published online Thursday by the journal Science, they described how the electronic circuitry could, in effect, be printed on a sheet of rubber.
Professor John Rogers of the University of Illinois explained that today's modern electronic circuits may perform well, but their physical form presents certain limitations.
ROGERS: "All known silicon electronics, high-performance silicon electronics, is built on rigid, brittle wafers of silicon. So these are round plates that are easily broken if they're dropped. They are not bendable, certainly not stretchable, but they serve as a fantastic substrate for forming high-quality electronics."
So what Rogers and his colleagues did is essentially grind off the bottom of the silicon wafer, the substrate, leaving just the thin part that actually contains the electronic circuitry. It's also made of silicon, which should be brittle, but it's thin enough — less than two thousandth of a millimeter — that it's very flexible. He draws a parallel using a heavy piece of construction lumber called a two-by-four.
ROGERS: "If you look at a two-by-four, and you compare its mechanical properties to a sheet of paper, you realize the sheet of paper is bendable, the two-by-four is not. The materials are basically the same. It's really by virtue of the small thickness of the paper that enables it to be bendable."
A flexible computer chip could potentially provide some advantages over today's rigid chips in some familiar applications.
ROGERS: "You eliminate a lot of the packaging that people have to put around these rigid chips to prevent them from breaking when you drop your laptop, for example. so you might be able to strip out a lot of that packaging that's currently put around the wafers if you have your system on a rubber substrate because it's just intrinsically much more mechanically rugged."
But John Rogers says the really interesting possibilities emerge when you starting thinking about entirely new ways to use computer circuits, while keeping the same high operational performance we've come to expect from today's electronics. One possibility is using these circuits in health monitors that could be worn on, or even implanted in, the body. Another might include something that could help surgeons in the operating room.
ROGERS: "So there we're putting electronics and sensors onto latex gloves and designing them in such a way that the tips of the fingers in the glove provide a sensing capability for measuring blood oxygen content, blood pH, temperature, and so on of the patient during the operation."
Rogers says these stretchable and foldable silicon integrated circuits could extend the transistor revolution to new applications.
Time again for our Website of the Week, when we showcase interesting and innovative online destinations.
March is Women's History Month, and the theme this year is "Women's Art: Women's Vision," so for our last featured website this month, we highlight Intimate Circles, a site focusing on American women in the arts and the links that connect them. Nancy Kuhl calls them 'circles of friends.'
KUHL: "Groups of people in similar places or who crossed paths in similar places or in the same place, influenced one another. So that when folks who moved from Chicago to New York to Paris, as some of the women did, the women that they met and the artists that they met along that path, all of those circles of artist friends, their circle in Chicago then sort of bleeds into and is also influencing and influenced by similar groups of artists in New York and elsewhere."
KUHL — an associate curator at Yale's Beinecke Rare Book and Manuscript Library — says she took the most inclusive approach possible in deciding who could be considered a "woman in the arts." She ended up with 61 women...
KUHL: "Everything from the most famous writers and performers to behind-the-scenes people who you might not expect, people like art critics and historians, patrons, women who hosted salons, theatrical producers, agents, translators, all of those what might be considered secondary contributions, but these are really crucial to the fabric of the sort of whole work of arts in this country, and especially at a period of some of the most exciting and radical changes in the arts."
Covering the period from the late 19th century through the mid-twentieth, the site organizes the women into overlapping circles by their profession and where they lived and worked. Clicking on a name brings up a short biography and photos of the woman. Kuhl says an important part of the website is the section of essays that help put the artists — and their intersecting and intimate circles — into context.
KUHL: "Looking at the group from the Southwest, how the photographer Anne Brigman was connected to Mabel Dodge Luhan who was a writer and a very important salon hostess and how those two women might be connected to Georgia O'Keefe, a painter who you know was in New York and moved to the Southwest later. And how these people connect to some people whose names you might not recognize, like Mary Foote who was a portrait painter, and Elizabeth Shepley Sergeant who was a writer as well."
Meet those artists and other American women who helped shape culture and arts in their era, and in our own, at beinecke.library.yale.edu/awia/ or get the link from our site, voanews.com/ourworld.
MUSIC: TROUBLED WATER BY MARGARET BONDS
You're listening to a bit of music by Margaret Bonds — one of the Women in the Arts, on VOA's artfully done science and technology magazine, Our World. I'm Faith Lapidus, sitting in for Art Chimes in Washington.
Most babies are born after 40 weeks of pregnancy. However, a significant number of children come into the world early. And, as Rose Hoban reports, premature birth can lead to life-long problems.
HOBAN: There are many reasons why babies are born 'pre-term'. In developing countries, poor maternal care, poor nutrition for mothers, infections and disease can contribute to preterm birth. But some children in the industrialized world are also born early — and the numbers of preterm births are slowly rising. The reason for the increase is unclear.
Duke University obstetrics professor Geeta Swamy was interested in the long-term effects of being born prematurely.
SWAMY: We don't know a lot about what happens to those children [over the] long term, particularly as they grow up into adolescence and into adulthood and what implications does this have on their long-term health.
HOBAN: Swami was able to analyze the lifetime medical records of more than a million children born in Norway. She collected information about when they were born, what kinds of health problems they had and when they died.
Swamy focused on preterm children born before 37 weeks gestation, and also on children born before 28 weeks gestation… that's considered extremely preterm. She found children who were born early were also more likely to die early.
SWAMY: For girls, the increased risk of mortality was about 10 times higher than those born at term. And that's particularly true for those girls who were born extremely preterm. For boys who were born extremely preterm, they had about a five times increased risk of death during the early childhood age, up to about age 6, but they also had an increased risk mortality, up to about age 13.
HOBAN: Swamy says she also found long-term effects of being born early. Preterm children ended up completing fewer years of education. And they were less likely to have children of their own.
SWAMY: Among women who are born at term, roughly 70% of those women went on to reproduce or have a child. Among those women who were born extremely preterm, say, before 28 weeks, only 25% of those women actually went on to reproduce or have a child… We saw similar implications for men who are born preterm and term. For those who were born at term, about 50% of them went on to reproduce, compared to only about 14% of men who were born extremely preterm.
HOBAN: Swamy says scientists don't know for sure why prematurity confers such risk over the lifetime, and other studies are looking for those answers.
Her research is published in the Journal of the American Medical Association. I'm Rose Hoban.
In conventional power plants, heat from burning fossil fuels is used to boil water and make steam, which then turns turbines to generate electricity. The same thing can happen when the heat comes from the sun. This method is called concentrating — or sometimes concentrated — solar power, and in sunny locations, it may prove more affordable than any other fuel. From sunny Las Vegas, Shelley Schlender reports.
SCHLENDER: The Las Vegas Strip is a fantasy of flashing neon, crowded theatres and high-tech hotels. Much of the electricity to keep it going comes from coal and natural gas-fossil fuels that are expensive, polluting… and running out.
A half-hour drive into the desert, a new electric power plant uses a clean fuel that's free and won't run out. From a distance, the Nevada Solar One plant makes a shimmer of blue, almost like a lake. Driving closer, the blue mirage turns into 200,000 mirrors that reflect the cloudless desert sky. Each mirror runs 6 meters high, tracking very slowly as they follow the sun across the sky. Plant manager Bob Cable says this is a concentrated solar power plant, and those mirrors are capturing solar energy.
CABLE: "We do it with mirrors. Yeah. The large parabolic structure with the mirrors focuses its energy into the focal point, where a receiver tube is, and we heat a heat transfer fluid up to approximately 390 degrees C."
SCHLENDER: That heat transfer fluid is an oil that is then used to boil water.
CABLE: "...which generates steam which turns a turbine and turns a generator and produces electricity."
SCHLENDER: It all begins with heating a black metal tube that runs above the middle of each mirror. Each mirror is curved to concentrate the solar thermal energy on this receiving tube, making it superhot. Thanks to concentrated solar power, Cable says that these 120 hectares of desert land make enough electricity for 14,000 households.
CABLE: "It's a very proven technology. I've been involved with this business 17 years now. I know it works. Very reliable, too. I'm comfortable with it. [I] would love to see a lot more of it."
SCHLENDER: So would Mark Mehos, the concentrating solar power expert at the National Renewable Energy Lab, in Golden, Colorado. Mehos says that the Southwestern U.S. has plenty of flat, sunny, open space for making electricity this way.
MEHOS: "With that optimal siting, we can supply more than 10 times the capacity used currently in the United States."
SCHLENDER: Concentrating solar power has similar potential anywhere that's sunny, such as Spain, North Africa and the Middle East. But solar energy provides less than one percent of the world's electricity. To make more, Mehos says we must lower costs, so that concentrated solar power is competitive with fossil fuels.
MEHOS: "Oh, I'm absolutely sure. We will get there. We need the policies in place and we need the research we do in the laboratory."
SCHLENDER: Much of the research is focused on the technological challenges throughout the system. Another scientist at the National Renewable Energy Lab, Cheryl Kennedy, is working on developing a better mirror.
KENNEDY: "Glass mirrors, very thin glass mirrors, aluminum mirrors, silver polymer mirrors, these are a multilayer coating mirror.. . ."
SCHLENDER: Her goal is to cut the cost of the mirrors in half, at least, and improve them in other ways.
KENNEDY: "We would like a perfect mirror that lasts forever, doesn't cost anything, weigh anything and never gets dirty."
SCHLENDER: Currently, when the sun sets, concentrated solar power plants shut down, including Nevada Solar One, which at 64 megawatts of power, is the world's 3rd largest. In order to operate into the night, they need affordable ways to store the oil that's been superheated by during the day. Adding to the challenge, one of the best "fluids" for retaining heat is molten salt, and salt is corrosive. So the inner coatings of the receiving tubes and thermal storage containers must be extremely durable as well as insulating. As scientists make that happen, Mark Mehos says that more plants will operate at night.
MEHOS: "If we can achieve that goal of reducing the costs of thermal storage, along with these other components, concentrating solar power will be used widely, I believe, in the U.S. and internationally."
SCHLENDER: Currently, Spain leads the way in this technology, with strong governmental subsidies and support for research. A Spanish company, ACCIONA, runs Nevada Solar One. Meanwhile, in Spain, a new plant opening this summer can store 7 hours of solar heat and run into the evening. And in Arizona, another Spanish company, Abengoa, is scheduled to open a 280 megawatt plant in 2011. It will be the world's largest, and will operate into the night.
The U.S. Department of Energy estimates that both concentrated and the more familiar photovoltaic solar power plants could replace fossil-fired ones, leading to near zero carbon emissions from electricity production in just a few decades. Mark Mehos is hopeful that the U.S. will invest more in this technology, to speed the transition to clean, solar fuel. For Our World, I'm Shelley Schlender in the desert outside of Las Vegas, Nevada.
MUSIC: "Our World" theme
That's our show for this week. If you'd like to to get in touch, email us at email@example.com. Or use the postal address —
Voice of America
Washington, DC 20237 USA
Ted Landphair edited the show this week. Eva Nenicka is the technical director. And this is Faith Lapidus, sitting in for 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.