Now in Sight: Far-Off Planets
NYT 14Nov2008-Dennis Overbye



A little more of the universe has been pried out of the shadows. Two groups of astronomers have taken the first pictures of what they say — and other astronomers agree — are most likely planets going around other stars. The achievement, the result of years of effort on improved observational techniques and better data analysis, presages more such discoveries, the experts said, and will open the door to new investigations and discoveries of what planets are and how they came to be formed.

“It’s the tip of iceberg,” said Christian Marois of the Herzberg Institute of Astrophysics in Victoria, British Columbia. “Now that we know they are there, there is going to be an explosion.” Dr. Marois is the leader of a team that recorded three planets circling a star known as HR 8799 that is 130 light-years away in the constellation Pegasus. The other team, led by Paul Kalas of the University of California, Berkeley, found a planet orbiting the star Fomalhaut, only 25 light-years from Earth, in the constellation Piscis Austrinus.

In an interview by e-mail, Dr. Kalas said that when he finally confirmed his discovery last May, “I nearly had a heart attack.” In scratchy telescope pictures released Thursday in Science Express, the online version of the journal Science, the planets appear as fuzzy dots that move slightly around their star from exposure to exposure. Astronomers who have seen the new images agreed that these looked like the real thing.

“I think Kepler himself would recognize these as planets orbiting a star following his laws of orbital motion,” Mark S. Marley of the Ames Research Center in Mountain View, Calif., wrote in an e-mail message elaborating on HR 8799. More than 300 so-called extrasolar planets have been found circling distant stars, making their discovery the hottest and fastest-growing field in astronomy. But the observations have been made mostly indirectly, by dips in starlight as planets cross in front of their home star or by wobbles they induce going by it. Astronomers being astronomers, they want to actually see these worlds, but a few recent claims of direct observations have been clouded by debates about whether the bodies were really planets or failed stars. “Every extrasolar planet detected so far has been a wobble on a graph,” said Bruce Macintosh, an astrophysicist from Lawrence Livermore National Laboratory in California and a member of Dr. Marois’s team. “These are the first pictures of an entire system.”

The new planetary systems are anchored by young bright stars more massive than our own Sun and swaddled in large disks of dust, the raw material of worlds. The three planets orbiting HR 8799 are roughly 10, 9 and 6 times the mass of Jupiter, and orbit their star in periods of 450, 180 and 100 years respectively, all counterclockwise. The Fomalhaut planet is about three times as massive as Jupiter, according to Dr. Kalas’s calculations, and is on the inner edge of a huge band of dust, taking roughly 872 years to complete a revolution of its star. Both systems appear to be scaled-up versions of our own solar system, with giant planets in the outer reaches, leaving plenty of room for smaller planets to lurk undetected in the warmer inner regions. Dust rings lie even farther out, like the Kuiper belt of icy debris extending beyond the orbit of Neptune.

“This is a window into what our own solar system might have looked like when it was 60 million years old,” Dr. Marois said. Sara Seager, a planetary theorist at the Massachusetts Institute of Technology, said it was significant that the planets in both cases seemed to be associated with disks of dust, particularly Fomalhaut, one of the brightest and closest stars known to be host to a massive disk. “Fomalhaut is like a Hollywood star to astronomers, so we have some personal excitement here,” Dr. Seager said. “It feels like finding out that one of your four closest friends just won the lottery big time” Alan Boss, a planetary theorist at the Carnegie Institution of Washington, said the triple-planet system in Pegasus was particularly promising, “as we expect planets to form in systems in general, whereas spurious background interlopers will generally appear as single ‘planets.’ ” But he and others cautioned that much more study of these objects was necessary and that the masses imputed to them were still highly uncertain. Being able to see planets directly opens the door to spectroscopic observations that can help determine the composition, temperature and other physical characteristics of planets and allow for comparisons with one another and with their parent stars. Dr. Macintosh said he hoped to train a spectroscope on his new planets as early as Monday.

The new images are the fruits of a long campaign by astronomers to see more and more of the unseeable. In particular, it is a triumph for the emerging technology of adaptive optics, in which telescope mirrors are jiggled and warped slightly many times a second to compensate for the atmospheric turbulence that blurs star images. The problem in seeing other planets is picking them out of the glare of their parent stars, which are millions of times brighter, at least in visible light. As a result, planet hunters usually look for infrared, or heat radiation, which is emitted copiously by planets still shedding heat from the process of formation. For their observations, Dr. Marois and his colleagues used the 8-meter in diameter Gemini North and the 10-meter Keck telescopes on Mauna Kea in Hawaii, both of which had been fitted with adaptive optics. Then they processed the images with a special computer program, which Dr. Marois described as “a software coronagraph,” for processing the images. The team first spied a pair of dots about four billion and six billion miles out from HR 8799 in October last year. Following up, they discovered a third planet closer in, at about two billion miles. Then they discovered an old observation from 2004, which also showed the planets and how far they had moved around the star in three years. “Seeing the orbit is one of the coolest things,” Dr. Macintosh said.

Dr. Kalas did his work with the Hubble Space Telescope, which is immune to turbulence because it is in space. He used a coronagraph to block light from the actual star. He said he had been driven to look for a planet around Fomalhaut after Hubble photographs in October 2004 showed that a dust ring around the star had a suspiciously sharp inner edge, often a clue that the ring is being sculpted by the gravity of some body orbiting nearby. A second set of Hubble observations, in July 2006, revealed a dot moving counterclockwise around the star. “I basically held my breath for three days until I could confirm the existence of Fomalhaut in all of my data,” Dr. Kalas recalled.

Fomalhaut is also a young star, about 200 million years old, and its dust ring extends 11 billion to 20 billion miles from its planet, Dr. Kalas said. In order not to disturb or roil the dust ring, Fomalhaut’s planet must be less than three Jupiter masses, well within regulation planet size, Dr. Kalas and his collaborators calculated. A more detailed analysis, with another team member, Eugene Chiang of the University of California, Berkeley, as lead author will appear in the Astrophysical Journal, Dr. Kalas said. In an e-mail message, Dr. Kalas pointed out that Fomalhaut was the closest exoplanet yet discovered, “close enough to contemplate sending spacecraft there.”
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- posted by Andy @ 6:45 PM

 
Report Sees New Pollution Threat
- Andrew Jacobs NYT November 14, 2008

BEIJING — A noxious cocktail of soot, smog and toxic chemicals is blotting out the sun, fouling the lungs of millions of people and altering weather patterns in large parts of Asia, according to a report released Thursday by the United Nations. The byproduct of automobiles, slash-and-burn agriculture, cooking on dung or wood fires and coal-fired power plants, these plumes rise over southern Africa, the Amazon basin and North America. But they are most pronounced in Asia, where so-called atmospheric brown clouds are dramatically reducing sunlight in many Chinese cities and leading to decreased crop yields in swaths of rural India, say a team of more than a dozen scientists who have been studying the problem since 2002. “The imperative to act has never been clearer,” said Achim Steiner, executive director of the United Nations Environment Program, in Beijing, which the report identified as one of the world’s most polluted cities, and where the report was released.

The brownish haze, sometimes in a layer more than a mile thick and clearly visible from airplanes, stretches from the Arabian Peninsula to the Yellow Sea. In the spring, it sweeps past North and South Korea and Japan. Sometimes the cloud drifts as far east as California. The report identified 13 cities as brown-cloud hot spots, among them Bangkok, Cairo, New Delhi, Tehran and Seoul, South Korea.

It was issued on a day when Beijing’s own famously polluted skies were unusually clear. On Wednesday, by contrast, the capital was shrouded in a thick, throat-stinging haze that is the byproduct of heavy industry, coal-burning home heaters and the 3.5 million cars that clog the city’s roads. Last month, the government reintroduced some of the traffic restrictions that were imposed on Beijing during the Olympics; the rules forced private cars to stay off the road one day a week and sidelined 30 percent of government vehicles on any given day. Over all, officials say the new measures have removed 800,000 cars from the roads.

According to the United Nations report, smog blocks from 10 percent to 25 percent of the sunlight that should be reaching the city’s streets. The report also singled out the southern city of Guangzhou, where soot and dust have dimmed natural light by 20 percent since the 1970s. In fact, the scientists who worked on the report said the blanket of haze might be temporarily offsetting some warming from the simultaneous buildup of greenhouse gases by reflecting solar energy away from the earth. Greenhouse gases, by contrast, tend to trap the warmth of the sun and lead to a rise in ocean temperatures.

Climate scientists say that similar plumes from industrialization of wealthy countries after World War II probably blunted global warming through the 1970s. Pollution laws largely removed that pall.
Rain can cleanse the skies, but some of the black grime that falls to earth ends up on the surface of the Himalayan glaciers that are the source of water for billions of people in China, India and Pakistan. As a result, the glaciers that feed into the Yangtze, Ganges, Indus and Yellow Rivers are absorbing more sunlight and melting more rapidly, researchers say.

According to the Chinese Academy of Sciences, these glaciers have shrunk by 5 percent since the 1950s and, at the current rate of retreat, could shrink by an additional 75 percent by 2050. “We used to think of this brown cloud as a regional problem, but now we realize its impact is much greater,” said Veerabhadran Ramanathan, who led the United Nations scientific panel. “When we see the smog one day and not the next, it just means it’s blown somewhere else.” Although the clouds’ overall impact is not entirely understood, Mr. Ramanathan, a professor of climate and ocean sciences at the University of California, San Diego, said they might be affecting precipitation in parts of India and Southeast Asia, where monsoon rainfall has been decreasing in recent decades, and central China, where devastating floods have become more frequent. He said that some studies suggested that the plumes of soot that blot out the sun have led to a 5 percent decline in the growth rate of rice harvests across Asia since the 1960s.

For those who breathe the toxic mix, the impact can be deadly. Henning Rodhe, a professor of chemical meteorology at Stockholm University, estimates that 340,000 people in China and India die each year from cardiovascular and respiratory diseases that can be traced to the emissions from coal-burning factories, diesel trucks and wood-burning stoves. “The impacts on health alone is a reason to reduce these brown clouds,” he said.
-- Andrew C. Revkin contributed reporting from New York.
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- posted by Andy @ 6:40 PM

 
A Rise in Kidney Stones Is Seen in U.S. Children
By Laurie Tarkan NYT 28 Oct 2008

To the great surprise of parents, kidney stones, once considered a disorder of middle age, are now showing up in children as young as 5 or 6. While there are no reliable data on the number of cases, pediatric urologists and nephrologists across the country say they are seeing a steep rise in young patients. Some hospitals have opened pediatric kidney stone clinics.

“The older doctors would say in the ’70s and ’80s, they’d see a kid with a stone once every few months,” said Dr. Caleb P. Nelson, a urology instructor at Harvard Medical School who is co-director of the new kidney stone center at Children’s Hospital Boston. “Now we see kids once a week or less.” Dr. John C. Pope IV, an associate professor of urologic surgery and pediatrics at the Monroe Carell Jr. Children’s Hospital at Vanderbilt in Nashville, said, “When we tell parents, most say they’ve never heard of a kid with a kidney stone and think something is terribly wrong with their child.”

In China recently, many children who drank milk tainted with melamine — a toxic chemical illegally added to watered-down milk to inflate the protein count — developed kidney stones. The increase in the United States is attributed to a host of factors, including a food additive that is both legal and ubiquitous: salt.

Though most of the research on kidney stones comes from adult studies, experts believe it can be applied to children. Those studies have found that dietary factors are the leading cause of kidney stones, which are crystallizations of several substances in the urine. Stones form when these substances become too concentrated. Forty to 65 percent of kidney stones are formed when oxalate, a byproduct of certain foods, binds to calcium in the urine. (Other common types include calcium phosphate stones and uric acid stones.) And the two biggest risk factors for this binding process are not drinking enough fluids and eating too much salt; both increase the amount of calcium and oxalate in the urine. Excess salt has to be excreted through the kidneys, but salt binds to calcium on its way out, creating a greater concentration of calcium in the urine and the kidneys.

“What we’ve really seen is an increase in the salt load in children’s diet,” said Dr. Bruce L. Slaughenhoupt, co-director of pediatric urology and of the pediatric kidney stone clinic at the University of Wisconsin. He and other experts mentioned not just salty chips and French fries, but also processed foods like sandwich meats; canned soups; packaged meals; and even sports drinks like Gatorade, which are so popular among schoolchildren they are now sold in child-friendly juice boxes. Children also tend not to drink enough water. “They don’t want to go to the bathroom at school; they don’t have time, so they drink less,” said Dr. Alicia Neu, medical director of pediatric nephrology and the pediatric stone clinic at Johns Hopkins Children’s Center in Baltimore. Instead, they are likely to drink only once they’re thirsty — but that may be too little, too late, especially for children who play sports or are just active.

“Drinking more water is the most important step in the prevention of kidney stones,” Dr. Neu said. The incidence of kidney stones in adults has also been rising, especially in women, and experts say they see more adults in their 20s and 30s with stones; in the past, it was more common in adults in their 40s and 50s. “It’s no longer a middle-aged disease,” Dr. Nelson said. “Most of us suspect what we’re seeing in children is the spillover of the overall increase in the whole population.” The median age of children with stones is about 10. Many experts say the rise in obesity is contributing to kidney stones in children as well as adults. But not all stone centers are seeing overweight children, and having a healthy weight does not preclude kidney stones. “Of the school-age and adolescent kids we’ve seen, most of them appear to be reasonably fit, active kids,” Dr. Nelson said. “We’re not seeing a parade of overweight Nintendo players.” Dr. Slaughenhoupt has seen more overweight children at his clinic. “We haven’t compared our data yet,” he said, “but my sense is that children with stones are bigger, and some of them are morbidly obese.” Dr. Pope, in Nashville, agreed. His hospital lies in the so-called stone belt, a swath of Southern states with a higher incidence of kidney stones, and he said doctors there saw two to three new pediatric cases a week. “There’s no question in my mind that it is largely dietary and directly related to the childhood obesity epidemic,” he said.

Fifty to 60 percent of children with kidney stones have a family history of the disease. “If you have a family history, it’s important to recognize your kids are at risk at some point in their life,” Dr. Nelson said. “That means instilling lifelong habits of good hydration, balanced diet, and avoiding processed high-salt, high-fat foods.” There is also evidence that sucrose, found in sodas, can also increase risk of stones, as can high-protein weight-loss diets, which are growing in popularity among teenagers.

A common misconception is that people with kidney stones should avoid calcium. In fact, dairy products have been shown to reduce the risk of stones, because the dietary calcium binds with oxalate before it is absorbed by the body, preventing it from getting into the kidneys. Children with kidney stones can experience severe pain in their side or stomach when a stone is passing through the narrow ureter through which urine travels from the kidneys to the bladder. Younger children may have a more vague pain or stomachache, making the condition harder to diagnose. Children may feel sick to their stomach, and often there is blood in the urine.
One Saturday last February, 11-year-old Tessa Cesario of Frederick, Md., began having back pains. An aspiring ballerina who dances en pointe five nights a week, she was used to occasional aches and strains. But this one was so intense that her parents took her to the doctor. The pediatrician ordered an X-ray, and when he phoned with the results, her parents were astonished. “I was afraid he was calling to say she pulled something and wouldn’t be able to dance,” said her mother, Theresa Cesario. Instead, they were told that Tessa had a kidney stone. “I thought older men get kidney stones, not kids,” Ms. Cesario said.

The treatment for kidney stones is similar in children and adults. Doctors try to let the stone pass, but if it is too large, if it blocks the flow of urine or if there is a sign of infection, it is removed through one of two types of minimally invasive surgery. Shock-wave lithotripsy is a noninvasive procedure that uses high-energy sound waves to blast the stones into fragments that are then more easily passed. In ureteroscopy, an endoscope is inserted through the ureter to retrieve or obliterate the stone. Tessa Cesario is taking a wait-and-see approach. Her stone is not budging, so her parents are putting off surgery until they can work it into her dance schedule. In the meantime, she has vastly reduced her salt intake by cutting back on sandwich meats, processed soups and chips. And, her mother said, “she drinks a ton more water.”
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- posted by Andy @ 4:33 PM

 
Long workouts best for raising good cholesterol
Reuters - Thu May 31, 2007 6:12 PM ET

NEW YORK (Reuters Health) - People who want to boost their "good" HDL cholesterol levels with exercise will have to put in at least two hours of physical activity each week, an analysis of 25 studies shows.

And the longer each exercise session, the greater the effect, Dr. Satoru Kodama of Ochanomizu University in Tokyo and colleagues found. While the effect of exercise in increasing levels of HDL cholesterol is well known, studies have had varying results, Kodama and his team note in the Archives of Internal Medicine.

To clarify the relationship between the intensity and duration of exercise sessions and magnitude of HDL cholesterol reduction, the researchers analyzed 25 different randomized controlled trials looking at exercise and good cholesterol. Overall, the researchers found, exercisers increased their HDL cholesterol by a modest but significant 2.53 mg/dL, which equates to a roughly 5 percent drop in heart disease risk for men and a nearly 8 percent reduction for women.

In order for exercise to have an effect on HDL cholesterol, study participants had to expend at least 900 kilocalories a week in physical activity, equivalent to about 120 minutes of exercise. The researchers also found that the intensity of exercise or the frequency of exercise sessions didn't seem to matter, as long as exercise was performed consistently. However, the length of an exercise session did matter; for every 10 minutes longer a workout session lasted, there was an additional 1.4 mg/dL rise in good cholesterol.

The researchers also found that exercise had the greatest effect in increasing HDL cholesterol in people with body mass indexes less than 28 and those who had total cholesterol levels of 220 mg/dL or greater. While the effect of exercise identified in the study is likely smaller than that seen with HDL-boosting medications, including niacin and fibrates, the effect "is potentially of substantial importance to public health," the authors conclude.

SOURCE: Archives of Internal Medicine, May 28, 2007.
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- posted by Andy @ 5:25 PM

 
Moving Faster on Refrigerant Chemicals
By Keith Bradsher - New York Times
Published: March 15, 2007

HONG KONG, March 14 — An unusual coalition of industrial and developing countries began pushing Wednesday for stringent limits on the world’s most popular refrigerant for air-conditioners, as evidence mounts that the refrigerant harms the earth’s ozone layer and contributes to global warming.

The coalition is pitted against China, which has become the world’s leading manufacturer of air-conditioners that use the refrigerant, HCFC-22. Most window air-conditioners and air-conditioning systems in the United States use this refrigerant, as well.

International pressure has grown rapidly this winter for quick action. “We scientifically have proof: if we accelerate the phaseout of HCFC, we are going to make a great contribution to climate change,” said Romina Picolotti, the chief of Argentina’s environmental secretariat. An accelerated phaseout of the refrigerant could speed up by five years the healing of the ozone layer of the atmosphere. It could also cut emissions of global-warming gases by the equivalent of at least one-sixth of the reductions called for under the Kyoto Protocol.

The United States joined Argentina, Brazil, Iceland, Mauritania and Norway on Wednesday in notifying the Ozone Secretariat of the United Nations Environment Program that they want to negotiate an accelerated phaseout of hydrochlorofluorocarbons, or HCFC’s, at an international conference in Montreal in September. The conference is tied to the 20th anniversary of the signing of the Montreal Protocol, which has reduced emissions of most ozone-depleting gases but left a loophole for HCFC-22 production by developing countries. China has repeatedly said it will honor all current rules of the Montreal Protocol but does not want to add new ones.

Recent studies have shown that steeply rising production of HCFC-22 by China, India and other developing countries has slowed the healing of the ozone layer, which protects humans, animals and vegetation from the sun’s dangerous ultraviolet rays. A report last week by five American and European scientists found that sharp cutbacks in emissions of ozone-depleting gases since 1987 have been far more effective in combating global warming than the Kyoto Protocol, the 1997 agreement that was aimed directly at limiting climate change.

HCFC’s and other ozone-depleting gases are extremely powerful warming gases. Gram for gram, the ones used as refrigerants have thousands of times the global-warming effect of carbon dioxide. The ozone-depleting gases are released in far smaller quantities, though, than carbon dioxide, which is emitted when fossil fuels are burned by vehicle engines, power plants and other users.

The report by the European and American experts, published last week in the Proceedings of the National Academy of Sciences, found that the Montreal Protocol had proved to be 5.5 times as effective as the Kyoto accord was intended to be in cutting emissions of global-warming gases. The Montreal agreement has been in force much longer and applies to developing and industrial nations alike, while the Kyoto Protocol has binding limits only for industrial nations. The report has caught the attention of countries in the Pacific and Indian Oceans that fear that global warming will lead to a rise in sea levels and a significant loss of their limited land. “As small island nations, our main concern is that whatever touches the climate has to be dealt with fairly quickly,” said Sateeaved Seebaluck, permanent secretary in the environment ministry of Mauritius, an island nation well east of Africa in the Indian Ocean. Mr. Seebaluck said that a flurry of news reports about HCFC-22 this winter had been widely e-mailed among specialists and had led to greatly increased international interest in addressing the problem.

The Montreal Protocol currently allows developing countries to keep increasing their production of HCFC-22 until 2016, and then freezes production at that level until 2040, when it is supposed to be halted. But that schedule was devised in the early 1990s, when HCFC-22 was used mainly in industrial nations; developing countries were seen as too poor ever to afford much of the chemical. The Kyoto Protocol then exempted HCFC-22 and other ozone-depleting substances from production and consumption limits on the grounds that the Montreal agreement had already addressed those matters.

Use of HCFC-22 has soared in the third world with the economic growth of China, India and other countries, along with the sharp drop in air-conditioner costs that has accompanied China’s growing skill in making them cheaply. Mr. Seebaluck said Mauritius’s use of HCFC-22 had risen more than 100-fold in the last six years because of a boom in hotel construction and the rapid expansion of the fishing industry, which uses a lot of refrigeration to preserve freshness. The use in India and China, far larger markets, has been rising as much as 35 percent a year lately, with specialists predicting that similar growth could last through 2016.

Industrial nations are required to phase out HCFC-22 by 2020, but most are moving faster. The European Union phased it out in 2004. The United States will ban domestic production in 2010 and is considering whether to ban imports then, as well. China has begun making air-conditioners with more modern refrigerants for the European market. But by continuing to produce HCFC-22 for markets elsewhere, the Chinese have been able to claim hundreds of millions of dollars a year in payments from an obscure United Nations agency. The payments are to compensate Chinese chemical factories for incinerating a waste gas generated as part of the manufacturing process for HCFC-22. If the Chinese industry switches to modern refrigerants, it would no longer produce the waste gas and so would lose the credits. India has a large and growing HCFC-22 industry that is also reaping a fortune in credits. But the Indian government has largely stayed on the sidelines in international talks, while China has called for industrial nations to pay even more for the incineration of waste gases from HCFC-22 production; China proposes to spend much of that to develop its renewable-energy industry.

A big problem is that no one has agreed what should replace HCFC-22. The chemicals requiring the fewest changes to air-conditioner designs avoid harm to the ozone layer but are still as potent, gram for gram, in terms of global warming. Mack McFarland, chief atmospheric scientist at DuPont, said the company had developed a chemical that also has little effect on global warming. But the chemical is suitable only for vehicle air-conditioners, not the building air-conditioners that now rely on HCFC-22. Environmentalists contend that chemical companies and air-conditioner makers are too slow to embrace other refrigerants, like ammonia or carbon dioxide, that may pose technical challenges but could be better for the ozone layer and global warming. “Industry certainly is somewhat concerned about some of those chemicals because some of them don’t promise a lot of profits,” said Alexander von Bismarck, campaigns director of the Environmental Investigation Agency, a Washington advocacy group. David Doniger, climate policy director at the Natural Resources Defense Council, said that even switching to new commercial refrigerants that are potent global-warming agents could help the environment. Air-conditioners designed for the new refrigerants tend to be more energy-efficient and often do not use as much refrigerant, he said.
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- posted by Andy @ 8:42 PM

 
Gabrielle the Moon far Xena

Neptune, Pluto... Xena and Gabrielle?
Sun, 02 Oct 2005 - CBC News

Astronomers say Saturday that an icy, rocky object that might be the solar system's 10th planet has its own moon. Scientists have dubbed the possible planet Xena and its much smaller satellite, Gabrielle.

They made the discovery on Sept. 10 using the Keck Observatory on Mauna Kea in Hawaii. "Since the day we discovered Xena, the big question has been whether or not it has a moon," Michael Brown, of the California Institute of Technology, said in a statement.
"Having a moon is just inherently cool -- and it is something that most self-respecting planets have, so it is good to see that this one does too."
Xena also goes by the more prosaic name 2003 UB313. It was discovered 2003, in an ongoing survey at Palomar Observatory's Samuel Oschin telescope.
Proclaiming a heavenly body a planet is controversial because there is no official definition of what a planet is.
A planet does not need to have a moon in order to deemed a planet. Neither Mercury nor Venus have moons. But the moon's discovery is significant because it can help determine the mass of the possible planet.

The moon is about 250 kilometres wide. It is currently 15 billion kilometres away from the sun, or about three times Pluto's current distance from the sun.
Astronomers know that Xena is bigger than Pluto but they don't know what it is made of, so they can't calculate its mass. But the discovery of the moon Gabrielle means Xena has at least enough mass to keep a satellite circling it.

Gabrielle was the name of the sidekick and pal in the former television series, Xena: Warrior Princess. This isn't the first discovery of a so-called 10th planet. In 2000, 2000 EB173 was discovered using the CIDA observatory in Merida, Venezuela.
Copyright ©2005 Canadian Broadcasting Corporation - All Rights Reserved

- posted by Andy @ 2:12 PM

 
How to prepare a planet for global warming
By Peter N. Spotts | Staff writer of The Christian Science Monitor
Christian Science Monitor - 18 March 2005

** Convinced the phenomenon is inevitable, some scientists now focus on coping with it. **

Scientists have long warned that some level of global warming is a done deal - due in large part to heat-trapping greenhouse gases humans already have pumped skyward.

Now, however, researchers are fleshing out how much future warming and sea-level rise the world has triggered. The implicit message: "We can't stop this, so how do we live with it?" says Thomas Wigley, a climate researcher at the National Center for Atmospheric Research (NCAR) in Boulder, Colo.

One group, led by Gerald Meehl at NCAR, used two state-of-the-art climate models to explore what could happen if the world had held atmospheric concentrations of greenhouse gases steady since 2000.

The results: Even if the world had slammed on the brakes five years ago, global average temperatures would rise by about 1 degree Fahrenheit by the end of the 21st century. Sea levels would rise by another 4 inches over 20th-century increases, just from expansion of the warming water. Rising sea-levels would continue well beyond 2100, even without adding water from melting glaciers and ice sheets. The rise highlights the oceans' enormous capacity to absorb heat and its slow reaction to changes in atmospheric conditions.

The team ran each model several times with a range of "what if" concentrations, as well as observed concentrations, for comparison.

Temperatures eventually level out, Dr. Meehl says in reviewing his team's results. "But sea-level increases keep on going. The relentless nature of sea-level rise is pretty daunting."

Dr. Wigley took a slightly different approach with a simpler model. He ran simulations that capped emissions, as well as concentrations, at 2000 levels. And he ran his calculations out to the year 2400. If concentrations are held constant, warming could exceed 1.8 degrees F. by 2400. If annual emissions are held at 2000 levels, warming could range from nearly 4 degrees to roughly 11 degrees F. The outcome depends on how sensitive the climate truly is to changes in greenhouse gases.

Wigley also calculates rates of sea-level rise. These range from 4 inches per century when limiting greenhouse- gas concentrations, to nearly 10 inches if annual emissions are held at 2000 levels. In this case, melting glaciers and ice sheets are taken into account.

The two researchers add that far from holding steady, concentrations of greenhouse gases continue to rise. Thus, at best, the results point to the least change people can expect, they say.

Both studies were published in Friday's edition of the journal Science.

The idea that some level of global climate change from human activities is inevitable is not new. But the word has been slow to make its way into the broader debate.

"Many people don't realize we are committed right now to a significant amount of global warming and sea-level rise. The longer we wait, the more climate change we are committed to in the future," Meehl says.

These studies are part of a wider effort to build the basis for the Intergovernmental Panel on Climate Change's next set of reports, slated for release in 2007.

While the concept of climate-change commitment isn't new, these fresh results "tell us what's possible and what's realistic" and that for the immediate future, "prevention is not on the table," says Roger Pielke Jr., director of the Center for Science and Technology Policy Research at the University of Colorado at Boulder.

To Pielke and others, this means adaptation should be given a much higher priority that it's received to date. "There's a cultural bias in favor of prevention," he says. But any sound policy includes preparation as well, he adds. "We have the scientific and technological knowledge we need to improve adaptation" and apply that knowledge globally.
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- posted by Andy @ 4:19 PM

 
Chemical Analysis Of Mushrooms Shows Their Nutritional Benefits

Source: University Of Illinois At Urbana-Champaign
Date: 2005-02-22
URL: http://www.sciencedaily.com/releases/2005/02/050218161310.htm

CHAMPAIGN, Ill. -- An analysis of previously uncharted chemical contents, mostly carbohydrates, in U.S.-consumed mushrooms shows that these fruity edible bodies of fungi could be tailored into dietary plans to help fill various nutritional needs.

Using modern analytic tools, scientists at the University of Illinois at Urbana-Champaign found that the six mushroom varieties tested -- in raw and cooked forms and at various harvest times and maturity levels -- are rich in total dietary fibers, including those associated with cholesterol-lowering (chitin) and healthy hearts (beta-glutan).

The findings appear online in advance of regular publication by the Journal of Agricultural and Food Chemistry. The same researchers last year reported in the same journal the carbohydrate profile of selected plum and prune products. The findings will become part of the U.S. Department of Agriculture's National Nutrient Database.

"What we've reported in these papers are the complete carbohydrate profiles of these two lines of popular foods," said George C. Fahey Jr., a professor of nutritional sciences in the department of animal sciences at Illinois. "These profiles include the digestible carbohydrates, the starches and the fermentable fibers that reach the large bowel. This work was important to the two commodity organizations that funded this research, because they had little information on these components." It was already known that mushrooms offer high-quality protein, vitamins, unsaturated fatty acids and fiber, but a precise carbohydrate breakdown had been elusive.

The mushrooms studied were white button, crimini and portabella, all of which represent different maturity levels of Agaricus bisporus, and maitake (Grifola frondosa), shiitake (Lentinus edodes) and enoki (Flammulina velutipes). The latter two mushrooms were analyzed only in their consumed cooked form.

"The maitakes and shiitakes tended to be very similar in their nutrient concentrations, and quite a bit different than the others," said Cheryl L. Dikeman, a doctoral student in Fahey's lab and lead author on both papers. "Portabellas were off on their own in terms of their contents of oligosaccharides, beta-glucans and chitin."

Chitin concentrations were 8 percent in raw, mature portabellas and 6 percent in raw, immature ones. When cooked, chitin content fell to 2.7 percent in both forms, but their levels of total dietary fibers went up significantly. Also showing the same pattern were raw enokis, which had a 7.7 percent chitin content; cooking also lowered it to 2.7 percent but total dietary fibers jumped from 29.3 percent in raw to 41.6 percent in cooked. Raw, mature white buttons and cooked, mature shiitakes boasted chitin levels of 3 percent and 3.6 percent, respectively. Raw, mature portabellas also had the highest level of beta-glucan (0.2 percent), while most of the other mushrooms had 0.1 percent. Enokis and maitakes had none. Relatively small amounts are required to provide cardiovascular benefits, Fahey said.

Cooking tended to increase starch, total dietary fibers and fat contents and to decrease chitin concentrations in all of the mushrooms. "Some nutrients went up after cooking, while some went down," Dikeman said. "Part of that you'd expect to happen as water is cooked out."

Also measured were oligosaccharide levels. These sugar molecules are only partially digestible, but the undigested components are considered prebiotics in that they elicit growth of healthful bacteria in the colon. Raw, immature portabellas had a total oligosaccharide concentration of 5,272 micrograms per gram (ug/g). Also found to have more than 1,000 ug/g were raw, mature portabellas and cooked, immature crimini. None were detected in enokis, maitakes or shiitakes. Most of the total oligosaccharides were in the form of glucooligosaccharides, but fructooligosaccharides (FOS) accounted for the total concentrations in cooked, immature white buttons. FOS did not appear in other samples. In other findings: White buttons had the highest levels of ash; starch was highest in maitakes and shiitakes; and crude protein and acid-hydrolyzed fats were highest in crimini, white buttons and maitakes.

For plums and prunes, which are known to be good sources of dietary fiber, the researchers analyzed individual carbohydrate components that are in the various forms used by consumers: powders, juices, purees and fruits. They also looked at the waste byproducts, including dried plum pits. All of the prune/plum products were found to have high total concentrations of oligosaccharides and free sugars. High in total dietary fibers as a percentage of total dry-matter were generally the various powder and fruit products.

The research primarily involved the use of high-performance liquid chromatography, which was adapted by Laura L. Bauer, a research specialist in animal sciences and a co-author on both papers, to quantify chitin concentrations in each mushroom. A spectrophotometer was used to analyze beta-glucan levels and sort out uronic acids that are associated with total dietary fibers. The information obtained in the two studies, Fahey said, will allow people to choose the mushrooms and forms of plums and prunes that provide the dietary punch they may be needing. It also should allow food scientists to search for optimum preparation strategies for using the various products.

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The Mushroom Council of Dublin, Calif., funded the mushroom study and provided the samples. The plum/prune study was done with samples and funding provided by the California Dried Plum Board. Elizabeth A. Flickinger, a former postdoctoral researcher in Fahey's lab, also was a co-author on the plum/prune study.***
- posted by Andy @ 4:05 PM