VOA标准英语2009年-Our World — 19 December 2009（在线收听）

VOA's weekly science and technology magazine

Art Chimes 18 December 2009

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This week on Our World: President Obama at the Copenhagen climate conference ... an update on the H1N1 'swine' flu ... and Science magazine's breakthrough of the year ...

COONTZ:  "The main thing was that it walked upright, just as we do. All of this is very different from what people were expecting. And of course, scientists love surprises."

Finding a four-million-year-old human ancestor and other milestones of the year in science, and more.
 
I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."

Obama Stresses US Commitment at Climate Change Meeeting

The U.N. climate change conference in Copenhagen ended Friday.

In a speech to the final session, President Obama said the United States was committed to cutting greenhouse gas emissions, aiding poor countries in reducing their emissions, and supporting a system to ensure that countries keep their pledges.

OBAMA:  "We can embrace this accord, take a substantial step forward, continue to refine it, and build upon its foundation. We can do that, and everyone who is in this room will be a part of an historic endeavor - one that makes life better for our children and grandchildren."

Or, he said, we can choose to delay while the danger of climate change grows, until it is irreversible.

H1N1 (Swine) Flu Remains a Threat, says WHO

Perhaps a more immediate challenge facing the world is the H1N1, or swine flu pandemic. The World Health Organization this week said it is too soon to declare victory against the viral disease, which so far has killed nearly 8,000 people worldwide. A senior WHO official says countries should continue to take steps to protect their public health. Lisa Schlein reports from WHO headquarters in Geneva.

SCHLEIN:  The H1N1 influenza pandemic has been around for about eight months, but in some places the spread of the virus is not as widespread as some had feared. The World Health Organization says this is not long enough to be able to consider the pandemic over.

WHO notes the pandemic is a global event, not a regional one. Since the virus is spreading around the world, it says it is normal for the illness to be more severe in some places than in others.

For example, WHO finds infections are continuing at quite high levels in some parts of Europe, such as France and Switzerland, in parts of Central Asia, and in some large countries, such as Russia.

But Special Adviser to the WHO Director-General on Pandemic Influenza, Keiji Fukuda, says the pandemic seems to have peaked and is on the way down in some parts of the world, including North America and some European countries.

FUKUDA:  "But one of the big questions, which is still before us is whether we expect to see yet another wave of activity occur, perhaps in the late winter or in the early spring months. And the answer right now is that we simply are not able to answer this question right now." 

SCHLEIN:  Because of the uncertainties, he says WHO believes it is vital to provide support to vulnerable countries. And the best way to help them, he says, is by providing them with vaccines against the disease.

As of now, he says six manufacturers and 12 countries have pledged about 180 million doses of the vaccine to WHO. They will be distributed to approximately 95 countries.

FUKUDA:  "The first doses have not gone out yet. But, we are, I think very close to that." 

SCHLEIN:  Fukuda adds it is not too late to get the vaccines out to the countries.

FUKUDA:  "The pandemic virus is now a virus, which is really spread around the world. And it is quite likely this is an infection we will continue to see circulating for a number of years. And so, I think that it remains quite prudent to push ahead with the vaccinations." 

SCHLEIN:  Fukuda says Azerbaijan, Afghanistan and Mongolia will be the first three countries to receive the vaccines. He says they will be followed by a group of 35 countries. After that, the vaccines will be distributed to the remaining vulnerable countries on WHO's list.

Lisa Schlein for VOA News, Geneva.

Here in the United States, meanwhile, officials Thursday urged Americans to get vaccinated, saying there are ample supplies of the vaccine, which previously had been limited to high-risk groups.

For a variety of reasons, production of the H1N1 vaccine has lagged behind demand. The vaccine for the so-called swine flu is made in the same way as the seasonal flu vaccine - in chicken eggs. But the government's top infectious disease expert, Dr. Anthony Fauci, said the goal is to perfect new ways to make a vaccine.

FAUCI:  "What we really want to do is get away from that and get it to be 21st century technology - molecular biology, recombinant DNA technology, where you have very good control over the process. It's rapid, it's consistent, and it proves to be something that we can rely on."

Another long-term goal is to develop a vaccine that will attack parts of the flu virus that are unchanged from year-to-year. If scientists succeed, a new vaccine won't be needed for each new strain of flu, the way it's done today, and immunity should carry over from year to year.

Astronomers Discover More Earth-Like Planets, Including One with Water

We've got some astronomy news this week about the discovery of some more-or-less Earth-like planets circling distant stars.

First, astronomers report finding a planet that is about three times the diameter of Earth, and about 6.6 times more massive. For astronomers, that's pretty similar to our own planet. And David Charbonneau of the Harvard-Smithsonian Center for Astrophysics told reporters the similarity to Earth goes further: the planet likely has liquid water, he said, just like Earth. But it's very hot, and only very high atmospheric pressure keeps the water from boiling away.

CHARBONNEAU :  "The main difference here is that, although our planet is hotter, the higher pressure also ensures that water is liquid, but the surface of our planet probably wouldn't be anything like the surface of the Earth and therefore wouldn't host life as we know it."

Charbonneau led an international team of astronomers who report their discovery this week in the journal Nature.

A separate planet discovery was reported in the Astrophysical Journal, where scientists describe finding a total of six planets orbiting two sun-like stars.

Two of the planets are described as "super-Earths," meaning they are larger than Earth - about 5 to 8 times more massive in this case - but still a lot smaller than the gas giants in our solar system, Jupiter and Saturn.

University of California astronomer Gregory Laughlin, a member of the team that discovered the planets, says the two planets are composed largely of rock and metal, like Earth..

LAUGHLIN:  "But the excitement in these discoveries is that they point the way toward the detection of truly Earth-like planets in a very short period of time, within the next few years."

The planets were detected using some of the most advanced telescopes on Earth. But even big telescopes can't see a small planet next to a bright star, so the astronomers used an indirect method, measuring the wobble of the star that results from the gravitational pull of an orbiting planet.

Around 400 planets outside our solar system, called exoplanets, have been discovered so far, but relatively few are, like the ones reported this week, close enough in size and characteristics to be considered Earth-like.

NASA Spacecraft To Photograph the Entire Universe

One more bit of space news this week. On Monday, NASA launched a new telescope into orbit.

Officials say the new space telescope - known as the Wide-field Infrared Survey Explorer, or WISE, for short  - will help them to discover, photograph, and research thousands of previously undetected stars, galaxies, and potentially threatening asteroids. 

As VOA's MacKenzie Babb reports, WISE will allow scientists to look at the universe closer than ever before. 

BABB:  Have you ever looked up at the night sky and wondered what is out there? Well, NASA's Wide-field Infrared Survey Explorer, or WISE, is on a mission to find out.  Using a  41-centimeter telescope and infrared detectors, the spacecraft will spend the next nine months taking inventory of the cosmos. 

WISE Deputy Project Scientist Amy Mainzer explains the mission's all-sky survey, which will provide what she calls a "Google map to the universe."
 
MAINZER:  "It is literally looking everywhere, in the whole sky, and it will give us a map that we can use to find the most interesting places to look.  That is what we need to be able to use our big telescopes efficiently.  And also, too, if you want to find the most rare and unusual types of objects in the universe, you need to look everywhere to be able to find them."

BABB:  Mainzer says the panoramic picture of the sky WISE will provide is like a wide-angle lens for scientists, who will then use space telescopes, such as the Hubble and the upcoming James Webb, to zoom in on points of interest.
 
Researchers already have a good idea about some of the things WISE will find, such as ultra-luminous galaxies, thousands of previously unseen stars and about 100,000 undetected asteroids.
 
While Mainzer says most of these orbiting rocks will pose no harm to Earth, she does expect to find at least several-hundred new "near-Earth objects," or asteroids that may one day threaten civilization.
 
MAINZER:  "Now, that does not necessarily mean that they will hit the Earth at any time, but it is possible.  And because of that, we would like to know more about the near-Earth object population."

BABB:  WISE principal investigator Edward Wright says while scientists may not need to know the objects' size, composition and location right now, gathering such information is a necessary step toward future disaster prevention.

WRIGHT:  "So far, we do not know of anything on a collision course.  If we found out with enough warning, then it would be possible to launch a space mission and deflect the asteroid so it would not hit the earth, though we would need a lot of warning."

BABB:  Asteroids are just one of the estimated one-million never-before-seen objects scientists anticipate WISE to uncover.  But Mainzer and Wright agree the researchers' real expectation is to find the unexpected.
    
The last time the sky was mapped in infrared was in 1983 by the Infrared Astronomy Satellite.  Though revolutionary for its time, the craft's digital camera had only 62 pixels.  By contrast, the WISE camera has four million pixels, allowing it to photograph the universe with extraordinary sensitivity and in great detail.
  
MacKenzie Babb, VOA News, Washington

Website of the Week Highlights the Wonders of Snow

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

For those of us in the northern hemisphere, Monday is the first day of Winter, which seems a good time to check out a website that's all about snow.

LIBBRECHT:   "SnowCrystals.com is a website that is about snowflakes and snow crystals and generally ice phenomena."

Kenneth Libbrecht is a physics professor at Caltech, the California Institute of Technology, and for a decade he's been posting gorgeous photographs of snow flakes and a lot more at SnowCrystals.com.

LIBBRECHT:  "A little guide to different types of snow flakes. I talk some about the physics of snowflakes. And I even have a section on what I call 'designer snowflakes,' which is us growing crystals in the lab, trying to understand how the physics works." 

I had to ask him - as, apparently, everyone does: is it true that no two snowflakes are alike? Kenneth Libbrecht says it depends on what kind you're talking about, but if you mean the classic, complex six-sided version, the answer is yes.

LIBBRECHT:  "They are so complicated that if you tried to estimate how many ways you can make a snowflake, you get a huge number - not just billions or trillions, but bigger than the number of atoms in the universe. So the odds of seeing any two exactly alike are essentially zero."

Lots more - including videos of designer snow flakes being grown in the lab - at SnowCrystals.com, or get the link from our site, VOAnews.com.

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

4.4 Million Year Old Walking Hominid Highlights Science Magazine's Breakthroughs of the Year

The prestigious journal Science is out this week with its top 10 breakthroughs of 2009, and with us to talk about it is Robert Coontz, the magazine's deputy news editor.  Thanks for joining us.

COONTZ:  "My pleasure."

Q:  What do the editors of Science consider the top breakthrough of the year?

COONTZ:  "The top breakthrough of 2009 is the fossil Ardipithecus ramidus. And this 4.4 million year old fossil from Ethiopia may tell us things that we've never known before. It was very strange, it was very different from what anybody was expecting."

Q:  In what way?

COONTZ:  "The main thing was that it walked upright, just as we do. But what's unexpected about that is that our closest evolutionary relatives, chimpanzees and gorillas, don't do that. They walk crouched over, and they walk on their knuckles. And so there was an assumption that our common ancestor with them would have been something that also walked that way. And it turns out that, no, Ardipithecus was designed for walking in trees or climbing trees. All of this is very different from what people were expecting. And of course, scientists love surprises."

Q:  Well, speaking of surprises, we have several space-related breakthroughs of the year, and one of them was the identification of water on the moon, but a couple of others. Can we talk about those?

COONTZ:  "Certainly."

Q:  LCROSS was the name of the mission that NASA sent to look for water vapor and ice on the moon. Why is that important?

COONTZ:  "The poles of the moon have dark craters that never see sunlight because there are perpetual shadows that are cast over the rims of the craters. And those are some of the coldest places in the whole solar system. So if any were to wind up there, it really wouldn't go anywhere. So this year NASA sent up a spacecraft and sent up its rocket stage with it and sent the rocket stage right into the moon to 'bomb' the moon, basically, and see what came up. And they looked at it with a spectrometer and they found that the molecules that were coming up included water."

Q:  One of the best ways that scientists have had of looking out in space has been the Hubble Space Telescope. And there was a repair mission to the Hubble that made your list. Why is that on your list?

COONTZ:  "This mission gave Hubble a new lease on life. It's now taking better pictures than ever before, and it should be good for years to come."

Q:  And just finally, the other space item, briefly, the pulsars detected by the Fermi Gamma Ray Space Telescope.

COONTZ:  "That's right. Actually, this is part of a much broader work. Now the Fermi Gamma Ray Space Telescope looks in a very particular part of the electromagnetic spectrum. That is, it's a kind of light that's the highest energy light, gamma rays — beyond x-rays, beyond ultraviolet. And scientists had been able to look at stars and galaxies in that range before, but never with the kind of detail that the Fermi Gamma Ray Space Telescope lets them do."

Q:  Well, let's get a little more down to earth, and on the list of breakthroughs for 2009 we have gene therapy. That's one of those developments that always seems to be on the verge of a breakthrough. What's different this year?

COONTZ:  "Well, gene therapy has had some reverses in the past. And it's very promising, the idea that you can go in and if somebody has some sort of disease that's caused by a flaw in the DNA, you could actually go in and find ways to repair the DNA, and then the person would be cured of the disease. Unfortunately, although people have been talking about doing this for decades, it has never worked out quite as well as people expected.

"This year, however, there were some very promising clinical results that indicate that it may be starting to work the way that people always hoped that it would. There was a form of inherited blindness called Leber's congenital amaurosis, and some researchers in Britain injected the eyes of patients with these viruses attached to genes, harmless viruses that would carry the genes into to right places in the cells so that they would repair this form of blindness. And it turns out that the patients actually did regain some of their sensitivity to light, and in fact some of them who were children actually managed to play sports just normally. So that's very promising."

Q:  We don't have time for the rest of the Science magazine breakthroughs of the year, but you can read all about them at ScienceMag.org, where you can also get a heads-up on some areas that the journal flags as likely hot topics for 2010. Robert Coontz, what are some of those areas to watch?

COONTZ:  "Well, some of the hot areas that are coming up, there is almost certain to be a new wave of research in what's called induced pluripotent stem cells. These are these cells that can grow into almost any other kind of cell that you need in the body. And there're sure to be more studies of that in 2010.

"Also in 2010, there's a new satellite is going to be going up, actually an instrument to be installed on board the space station. It's called the Alpha Magnetic Spectrometer. It's going to be looking for cosmic rays, anti-matter, and strange particles that have been predicted but that nobody's ever seen before.

"This is also the year in which NASA is going to have to decide what it's going to do about the human space program. It will determine the whole direction that the future space program of the United States is going to take, and so that's something that we'll be looking at very closely."

Q:  OK, Robert Coontz, deputy news editor at the journal Science. Thanks very much for joining us.

COONTZ:  "Happy to help."

There are more breakthroughs of 2009 plus areas to watch in the coming year at ScienceMag.org.

Common Vision Disorder is on the Rise

Finally today ... Many people need glasses in order to see better, but do more people need glasses to see than in the past?

A new analysis of data shows that the number of people with myopia - who need glasses to see things at a distance - has increased over the past 40 years, at least in the United States. Health reporter Rose Hoban takes a look.

HOBAN:  No one is sure why people end up needing glasses to see distances. The number of people with poor distance vision changes with age, gender, ethnicity, occupation  - even which country you live in. 

Epidemiologist Susan Vitale from the U.S. National Eye Institute says the data suggest that the disorder has become more common because eye strain is a side effect of modern life.

VITALE: There are some known risk factors for myopia, they include having family history, like if your parents are nearsighted you are more likely to be nearsighted.  But it's not a one-to-one thing.  It's the same thing with having a higher educational level, where doing a lot more near work, or close up work, you have a greater risk for being myopic…

HOBAN:  Vitale says in some Asian countries, myopia is being called an epidemic. In China, about 2 of every 5 people are myopic, and the rate increases with the amount of education a person has.

To assess the rate of myopia in the United States, Vitale looked at data from large, nationwide health surveys done every decade.  In the early 1970s, researchers found that about 25 percent of people aged 12 to 54 years old had trouble seeing at a distance.
 
VITALE: When we applied that same definition to new data from '99 to 2004, we got a 41.6 rate, which is a really pretty big jump from 25 percent to 41 percent."

HOBAN:  Vitale says the good news is that myopia is easy to treat with corrective lenses - either glasses or contact lenses.  But if close to half the population needs glasses, those costs can add up.

Vitale says it's important for people with eye problems to see an eye doctor regularly in order to maintain good vision.  She also says if researchers could better identify the risk factors for deteriorating vision, perhaps they could prevent people from losing their eyesight in the first place.

Vitale's article is published in the Archives of Ophthalmology.

I'm Rose Hoban. 

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