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MUSIC: "Our World" theme
Straight ahead on "Our World," reining in climate change: a U.N. panel presents a plan of action ... a genetic piece of the longevity puzzle ... and what alcohol really does to your brain:
PAUL: "While alcohol is beneficial to the cardiovascular system, I think alcohol is doing something else to the neurons of the brain, the cells that make up the brain.
Those stories, the health benefits of coffee, and more. I'm Art Chimes. Welcome to VOA's science and technology magazine, "Our World."
A U.N. climate change panel on Friday urged reductions in our use of fossil fuels to reduce greenhouse gas emissions, saying the cost would be affordable and, in any event, cheaper than dealing with the consequences of global warming.
The report, released in Bangkok by the Intergovernmental Panel on Climate Change (IPCC) reflects the work of some 2,000 scientists from around the world. It says the technology already exists to avert a catastrophic increase in temperatures which could lead to rising sea levels, species extinction, disruptions in agriculture and possible breakdowns of society.
There would be significant costs involved, the report says — as much as three percent of the world's annual revenues — to stabilize carbon dioxide at slightly above current levels. But the IPCC's co-chair, Bert Metz, believes the price tag is affordable.
METZ: "There is substantial economic potential for reduction of these emissions over the coming decades, and in some scenarios could even reduce emissions below current levels."
The consensus report is aimed at helping policymakers make changes that will result in lower greenhouse gas emissions. Co-chair Ogunlade Davidson says it might help governments and businesses make decisions, for example, about a new power plant.
DAVIDSON: "There is enough evidence and there is enough information in the report to help countries, when they try to get new energy supply systems, and then you can shift to less fossil-fuel plants."
But the recommendations aren't just for governments and big companies. The report suggests travelers can help combat global warming by choosing more fuel-efficient vehicles or using public transportation. Farmers can improve manure management to reduce methane emissions. Home and business owners can help, too, by using high-efficiency appliances and lighting.
Rajendra Pachauri, who heads the IPCC, told reporters that bringing climate change under control is everyone's job.
PACHAURI: "So of course, you can look at technology, you can look at policies, but what is an extremely powerful message in this report is the need for human society as a whole to start looking at changes in lifestyle and consumption patterns."
One approach to carbon dioxide emissions that is getting a lot of attention involves capturing CO2 at a coal-burning power plant, for example, and then storing it where it can't harm the environment. Nature actually got the idea for carbon capture first. The oceans, in fact, absorb almost half the CO2 emitted from auto exhausts and factories. But new research suggests the ocean's role is more complex than we knew. Rosanne Skirble has details:
SKIRBLE: The surface of the ocean works a lot like a grassy lawn. Sunlight reaching plant organisms in the upper layers supports photosynthesis, converting light into energy and fixing carbon in the plant cells. These phytoplankton become food for fish and tiny marine animals or zooplankton. When they decompose, their debris falls like "marine snow" into a dimly-lit region between 100 and 500 meters that Ken Buesseler a senior scientist with Woods Hole Oceanographic Institution, calls "The Twilight Zone."
BUESSELER: "Think of it as carbon being speckled down, and there is a whole biome, there's a whole group of animals in these mid-waters that feed on this sinking carbon. And if they eat up that material before it sinks out, which is what happens to most of it, then it just gets converted back into inorganic carbon and exchanged back with the atmosphere."
SKIRBLE: Buesseler headed the VERTIGO expeditions in 2004 and 2005. These National Science Foundation-funded research cruises to the Pacific Ocean tracked how much carbon got beyond the Twilight Zone to the ocean's depths.
BUESSELER: "The findings were that in the warmer waters off Hawaii, that very little of the carbon reached the deep ocean. It was reduced by 80 percent from what was coming out of the surface 150-meter layer. That number was 50 percent in the North Pacific. So we are getting a lot more carbon through in that system."
SKIRBLE: Buesseler says a variety of factors could explain the regional difference.
BUESSELER: "It might have something to do with the combination of the temperature, simply by being 10 degrees Celsius colder in the northern waters. Things like bacteria that also feed on carbon, they're also one of the consumers that recycles carbon? It would slow down. And in those colder waters the plants that grow are actually much larger than the ones in Hawaii, and these large materials sink much faster and much more efficiently in these cold regions."
SKIRBLE: Buesseler is planning to lead another research cruise, this time to sample waters in Bermuda, a site monitored year-round. He hopes to compare the results with the data gathered in the VERTIGO expeditions in the Pacific.
BUESSELER: "We'd like to see how much that number changes — that carbon flux — how wide is that gate open at different times of the year in one system and see what is controlling that variability. So, are these extremes that we saw, the two examples that we saw measured in VERTIGO, characteristic of one site over different times of the year or are they more characteristic of the same site all year long?"
SKIRBLE: Buesseler says the data — difficult to collect — points to the importance of ocean observation. More than 40 biologists, chemists, physical oceanographers and engineers from 14 institutions and seven countries participated in the VERTIGO expeditions. Their findings are reported in the April 27 issue of the Journal Science. I'm Rosanne Skirble.
American researchers have discovered a gene that promotes longer life in earthworms that eat much less than normal. Humans have similar genes, and VOA's David McAlary reports that, if they work the same way as in the worms, a drug that mimics them might someday, if not extend life, at least make it healthier.
McALARY: Studies since the 1930s have shown that animals from fruitflies to monkeys increase their lifespan as much as 40 percent if they subsist on a near starvation diet. They also have less risk of cancer, diabetes, and heart disease and ailments caused by nerve degeneration.
But why is such a regimen beneficial? The answer has been elusive, but researchers at the Salk Institute for Biological Studies in La Jolla, California, say they have found a genetic reason. In a paper in the journal Nature, they identify a gene called pha-4 that makes hungry worms live longer.
DILLIN: "This is the first gene that is absolutely essential and specific for eliciting the dietary restriction response."
McALARY: This is Salk Institute researcher Andrew Dillin, speaking on a Nature magazine podcast. He says his experiments lengthened or shortened the lifespan of earthworms by altering the impact of the pha-4 gene. Those worms with normal levels of the gene lived longer when on a very low calorie regimen. When researchers amplified the gene, the worms lived even longer, even with a normal amount of food. When they inactivated it, the worms had a standard lifespan.
Dillin says humans have three genes similar to pha-4 and suggests that they are part of an internal defense mechanism to protect against famine.
DILLIN: "Definitely starvation is going to shorten your lifespan, but also the really high calorie diets are going to shorten our lifespan as well. But there is an intermediate level that actually increases lifespan in mammals by 30 to 40 percent. So there is this really small window where you are on the borderline of crossing into starvation or crossing into being fat. That is the calorie restriction window that we actually need to be in to increase longevity."
McALARY: It is a long evolutionary leap from earthworms to people, but Dillin says it is worth determining if the human versions of the pha-four gene operate the same way. The goal would be to develop a drug that could activate them so people could benefit from their effects without going on a near-starvation diet.
DILLIN: "Whether or not it is going to extend human longevity — I don't think that is actually the goal. The goal is actually to reduce the onset of these age-related diseases."
Time again for our Website of the Week, when we showcase interesting and innovative online destinations.
This week we turn to a website devoted to remembering one of the darkest periods of human history and preventing a repetition today.
SWIADER: "The U.S. Holocaust Memorial Museum website is a place that you can get, we hope, any answer to any question about the history of the holocaust and, especially, about modern-day genocide."
Lawrence Swiader is Chief Information Officer at the U.S. Holocaust Memorial Museum, online at ushmm.org. The museum and its website focus on Nazi Germany's efforts to exterminate Jews and other religious, ethnic and racial minorities across Europe.
The most popular feature on the site is the Holocaust Encyclopedia, a continuously-updated reference work now available in three languages with more coming, starting soon with Arabic and Farsi.
Swiader says visitors are interested in the stories of those who personally witnessed the Holocaust.
SWIADER: "Most people who come to the museum really want to hear first-person testimony - testimony by survivors, testimony by liberators and testimony by bystanders. And there are many, many tens of thousands of words of testimony available on our website in text form, in audio form, and in video form. And that's also one of our most-accessed resources."
Although the focus of the Holocaust Museum and its website is an attempt at genocide in Europe 60 years ago, it's other main concern is genocide in today's world. The museum recently announced a partnership with Google to better present details on the ongoing tragedy in the Darfur region of Sudan.
SWIADER: "They'll see over 1,600 villages throughout Darfur repressented by red and yellow flame icons that are the completely destroyed or partially destroyed homes, schools, mosques and other structures. They'll see pictures. They'll see video that they can access."
Lawrence Swiader of the U.S. Holocaust Memorial Museum website, online at ushmm.org, or get the link from our site, voanews.com/ourworld.
MUSIC: Brian Simpson — "I Remember When"
You're listening to VOA's science and technology magazine, Our World. I'm Art Chimes in Washington.
Three stories now about popular habits enjoyed worldwide: smoking, coffee, and alcohol. They often go together, and have been mired in health controversies for years. In a moment we'll learn about a new study linking secondhand smoke to a devastating medical condition, and one on alcohol and how it affects the brain. But first, my drug of choice: coffee.
Coffee has a long and fascinating history. Legend has it that an Ethiopian shepherd noticed his goats were more lively after eating coffee berries, so he tried some himself. Around the year 1100, coffee cultivation began on the Arabian peninsula. Dr. Lenore Arab of the University of California medical school in Los Angeles, says that in the 16th century, coffee was regarded with suspicion by the Christian establishment, led by Pope Clement VIII.
ARAB: "The pope was asked to condemn coffee because the Muslims were consuming it, and they thought it must be the drink of the devil. But he actually decided after trying it that this was a wonderful beverage and he actually blessed the coffee and decided that this was very useful because it kept the monks awake during their long vespers."
Loaded with caffeine, coffee is a natural stimulant. Drink too much and you can get edgy, nervous, jittery. For a long time, coffee was thought to be bad for your health. Coffee can raise your blood pressure, and caffeine is slightly addictive. But recent research has found that moderate coffee drinking — a few cups a day — can actually have some beneficial effects, and may even help reduce the risk of some serious diseases.
Dr. Rob van Dam of the Harvard School of Public Health has been studying the link between coffee — both regular and decaffeinated — and diabetes.
VAN DAM: "I think about 16 prospective studies around the world have now looked at coffee consumption in relation to Type II diabetes, and they consistently show that people who drink more coffee — talk about four or five cups a day — have a low risk of diabetes."
Van Dam was among several coffee experts who spoke this week at the Experimental Biology conference here in Washington. I asked him whether there might be other factors in the lives of coffee drinkers that might make them less suseptible to diabetes, such as weight, diet or exercise:
VAN DAM: "That's a very important consideration in this type of research. We see actually that people who drink more coffee are less health conscious, and they have a worse diet, and they smoke more, and they tend to have a somewhat higher body mass index. So actually, when we control for these factors more completely, we see a stronger effect, rather than a weaker effect."
Van Dam says some research has identified components in coffee that might be responsible for the effect. If that's confirmed, special coffee blends rich in those compoents might be marketed for diabetic consumers.
About two decades ago, a medical study suggested there might be a link between coffee and pancreatic cancer. But Dr. Arab, the UCLA epidemiologist who gave us some coffee history a few moments ago, says hundreds of other studies have shown that coffee drinkers are less likely to get certain types of cancer, starting with colorectal cancer.
ARAB: "There might be a 24 percent reduction with regular and higher consumption of coffee. There is also surprisingly interesting and consistent results with liver cancer, that is protective to the extent that drinking coffee regularly in Japan appears to be associated with a 50 percent reduction, and there's a dose-response [relationship] in some of the studies. It's gone down as far as a 70 percent reduction in those drinking more than five cups of coffee a day."
Not all cancers respond in the same way. Arab says there are some studies indicating that a pregnant woman who drinks coffee may put her unborn child at greater risk for childhood leukemia. Coffee may also increase the risk of stomach cancer.
Part of the challenge facing researchers is in quantifying coffee consumption. Blend, brewing method and strength are some variables; espresso is quite different from filter coffee. Also, a "cup" is the standard measure, but there is no standard cup. One restaurant may serve a 150-milliliter cup, but at many coffee shops here in America, a cup three times that size is only called "medium." In addition, according to James Coughlin, a scientist and consultant to the industry, the chemistry of coffee is enormously complex.
COUGHLIN: "I'm a chemist and a toxicologist, and I've studied the chemistry of coffee in very good detail. There's at least 2,000 components, individual chemical components, in coffee, which makes it difficult when we're looking at some of the positive beneficial health effects — we're trying to figure out what's in there that could be contributing to that story."
Like so many other things, coffee should be enjoyed in moderation. Drink much more than a liter a day, say experts, and you may have to balance some of coffee's beneficial effects with irritability, nervousness, and an upset stomach.
In many places, going out for a coffee means sitting in a smokey cafe, breathing in cigarette smoke even if you're not smoking yourself. That stuff you're breathing is called second-hand smoke.
Cigarette smoking has been known for decades to be a major cause of lung cancer and heart disease. More recent research has implicated tobacco in dementia. There has been much less focus on whether exposure to secondhand smoke could be linked to dementia.
Now, a new study has found that a non-smoker who has lived with a smoker for more than 30 years has a 30 percent greater risk of dementia.
Thaddeus Haight, a statistician at the University of California, studied a group of people who never smoked but who had lived with a smoker for years, or even decades.
HAIGHT: "It ranged from one to 80 years, and the median number of years was close to about 30.
Haight also found that the risk of dementia was compounded in patients who had a narrowing of the carotid arteries and other abnormalities. Those are the arteries in the neck that supply blood to the brain.
Non-smokers who were in that high exposure group - more than 30 years of living with a smoker - and who also had carotid artery disease were much more likely to develop dementia. Haight says secondhand smoke makes the existing failings in the carotid arteries much worse.
HAIGHT: "So if these people have some sort of underlying carotid disease as a result of, who knows what — cholesterol, aging — and coupled with secondhand smoke exposure, it may be accelerating that process."
Haight admitted that the number of years living with a smoker isn't a perfect measure of how much secondhand smoke you're exposed to, but he said it wasn't practical to try to evaluate all the possible variables of exposure, including decades when non-smokers routinely had to sit on trains or in restaurants or office with smokers.
And finally today, medical researchers have found that drinking small amounts of alcohol has benefits for the cardiovascular system. But what about its effect on the brain? As we hear from health reporter Rose Hoban, neuroscientist Carol Ann Paul began to wonder if alcohol could have similar positive effects on the brain.
HOBAN: Paul, an instructor at Wellesley College in Massachusetts, took data from the Framingham Study. That long-term medical research project has followed residents of the town of Framingham, Massachusetts since 1948. Several years ago, the Framingham researchers took brain scans of people in the community who ranged in age from 34–88 years. Paul looked at records from more than 18-hundred of them and divided them into five groups
PAUL: "And these groups were abstainers who didn't drink, former drinkers. And then I had three groups: low, moderate and high drinkers. Low drinkers had ione to seven drinks a week, moderate drinkers consumed 8 to 14 drinks per week while high drinkers downed greater or equal to 15 drinks a week."
HOBAN: Paul measured total cranial volumes and the amount of space the subjects' brains occupied inside their skulls. Brains normally get slightly smaller as people age, but Paul found the consumption of alcohol accelerated this process, even when she took other factors into account. And he says the more alcohol subjects drank, the more brain volume they lost.
PAUL: Alcohol decreased brain volume by minus 2.5 percent per drink category. Normal people lose about 0.19 percent of their brain per year, so this reduction is equal to one or two years of normal brain aging.
HOBAN: Paul says she doesn't know whether or how this decrease translates into decreased brain function. But she says she was surprised that alcohol had such a deleterious effect on brain structure.
PAUL: "What this suggests is that while alcohol is beneficial to the cardiovascular system, to the heart and the blood vessels ... and it probably has the same benefit to the blood vessels in the brain, I think alcohol is doing something else to the neurons of the brain - the cells that make up the brain."
HOBAN: Paul spoke to us from the annual meeting of the American Academy of Neurology in Boston, where she presented her research. I'm Rose Hoban.
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That's our show for this week. We're always interested in your comments. Email us at firstname.lastname@example.org. Or use the postal address —
Voice of America
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Rob Sivak edited the program. Felicia Butler 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.