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Friday, December 12, 2008

Cosmic diamonds may be hidden in 'carbon onions'

by Rachel Courtland

Diamond dust has been found in the infrared light of only three stars. That may be because diamonds are ordinarily cocooned in structures called 'carbon onions' (Illustration: NASA/JPL-Caltech/T Pyle/SSC)

Diamond dust has been found in the infrared light of only three stars. That may be because diamonds are ordinarily cocooned in structures called 'carbon onions' (Illustration: NASA/JPL-Caltech/T Pyle/SSC)

An exotic carbon structure could explain why astronomers have seen very little diamond dust in the universe.

Since the 1980s, researchers have puzzled over the origin of "nanodiamonds", tiny diamond deposits preserved in meteorites, such as the Allende meteorite that landed in Mexico in 1969.

These tiny diamonds make up roughly 3% of the carbon in the rocks. That suggests nanodiamonds should abound in clouds of interstellar gas and dust, possibly forged in the fiery blasts of previous supernovae.

But so far, signs of diamonds have only been found in the dusty discs around three young stars. Strangely, the diamonds are found close to the stars, as opposed to being distributed more evenly in the space around them. That hints that they were not left over from ancient stellar explosions but may have formed near the stars, at comparatively low pressures.

Now researchers led by Miwa Goto of the Max Planck Institute for Astronomy in Heidelberg, Germany, say they have come up with an explanation.

Nanodiamonds may be hidden from view in many places because they form within "carbon onions", exotic structures made up of concentric layers of graphite that can form in dusty material that is blasted with high-energy particles, the researchers say.

Right conditions

Carbon onions have been used to forge nanodiamonds on Earth. At high temperatures, researchers bombard the layered graphite with electrons. This knocks atoms out of the onions' outer shells, forcing the remaining atoms in the shells to rearrange and close ranks. The shells therefore squeeze inwards, eventually creating enough pressure at the centre of the onion to form diamond.

But conditions must be just right to produce diamonds in carbon onions around stars. A star must eject enough charged particles to turn onions into pressure cells.

Then, in order for astronomers to see the diamonds, one of two conditions must be met. There must either be a nearby source of X-rays that could slough off the outer layer of the onion to reveal the underlying gems, or the onions themselves must be warm enough – more than 300 °C – for the entire carbon onion to be turned into a nanodiamond.

The three stars that boast signs of diamonds are all massive young stars called Herbig Ae/Be stars. Notably, they all seem to have the required conditions to create carbon onion diamonds, Goto says.

Two of the stars have binary companion stars that emit large flares that could blast charged particles towards the onions. The other has a nearby X-ray source that has yet to be identified. All have dusty discs that are warm enough to sustain diamond growth.

Diamonds in the rough

"It's a new idea that should definitely be taken seriously," says Louis Allamandola of NASA's Ames Research Center in Moffett Field, California, who has studied cosmic diamonds.

But he adds that it's not clear how well the diamonds would survive continued irradiation by stellar flares. "If they can't cool down fast enough, they just basically erode, atoms just boil off," Allamandola told New Scientist.

Light from carbon onions may resemble that from other forms of carbon, making it difficult to confirm whether such structures orbit the star.

But carbon onions have been found in meteorites, including Allende. If future studies reveal nanodiamonds within those carbon onions, it would bolster the case that the universe is sprinkled with diamonds in the rough.

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Year's Biggest Full Moon Friday Night

By Robert Roy Britt

Champagne effect could help to predict volcanoes, says University of Oxford

The Anak Krakatau volcano

Earthquakes can set off volcanoes by shaking up molten rock like champagne in a bottle until they explode, a study suggests. The research shows that volcanoes erupt up to four times more often after a large earthquake than they would without the seismic agitation.

The effects of an earthquake can be felt hundreds of miles from the epicentre and are powerful enough to wake dormant volcanoes. However, it can take so long for a surge of molten rock to build up enough pressure to cause an eruption that several months can elapse between the trigger and the volcanic explosion.

The link between volcanoes and earthquakes has long been suspected but the new research has provided the first statistical evidence. Researchers at the University of Oxford identified the champagne effect after analysing records of volcanoes and earthquakes in southern Chile, the region where Charles Darwin first speculated on the likely link in 1835.

The research team found that the pattern of eruptions over the past 150 years showed a noticeable increase for a year after large earthquakes.

The volcano Tupungatito erupted within a year of both the 1906 and 1960 earthquakes, as did Calbuco and Villarrica. Osorno and Puntiagudo both erupted soon after Chile’s 1837 earthquake.

“The most unexpected part of this discovery was the considerable distance from the earthquake rupture where these eruptions took place, and the length of time for which we saw increased volcanic activity,” said Sebastian Watt, one of the researchers.

This suggests that seismic waves, radiating from the earthquake rupture, may trigger an eruption by stirring or shaking the molten rock beneath volcanoes.

“The disturbances that result from this lead to eruption but, because of the time it takes for pressure to build up inside a volcano and for magma to move towards the surface, an eruption may not occur until some months after the earthquake.”

There was a particularly strong effect in the wake of the great Chilean earthquake of 1960, the largest ever recorded with a magnitude of 9.5 on the Richter scale. The estimated death toll varies from 1,655 to 5,700, many of whom died because the quake prompted tsunamis in several countries.

Another of the earthquakes shown to have been followed by a succession of at least six volcanoes was that of 1906. In an average year just one volcano would have been expected.

"This work is important because it shows that the risk of volcanic eruption increases dramatically following large earthquakes in parts of the world, such as Chile, affected by these phenomena.

“Hopefully, our findings could help governments and aid agencies to manage volcanic hazards by showing the need for increased awareness of volcanic activity after large earthquakes.”

A report of the findings is to be published in the journal Earth and Planetary Science Letters.

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Man's genes 'key to baby's sex'

Sleeping baby
Family trees dating back to 1600 were studied.

A man's genetic make-up may play a role in whether he has sons or daughters, a study of hundreds of years of family trees suggests.

Newcastle University researchers found men were more likely to have sons if they had more brothers and vice versa if they had more sisters.

They looked at 927 family trees, with details on 556,387 people from North America and Europe, going back to 1600.

The same link between sibling sex and offspring sex was not found for women.

The precise way that genes can influence baby sex remains unproven.

But the Evolutionary Biology study could clear up a long-standing mystery - a flood of boy babies after World War I.

While a woman will always pass a female "X" chromosome via her egg to her child, the father effectively "decides" the sex of the child by passing on either another "X" in his sperm, making a girl, or a "Y" chromosome, making a boy.

The family tree study showed that whether you're likely to have a boy or a girl is inherited
Dr Corry Gellatly
Newcastle University

While the birthrate is almost 50/50, suggesting that overall men will deliver equal amounts of "X" sperm and "Y" sperm, scientists have suspected that in some individual couples the balance is shifted in favour of either boys or girls.

Various explanations have been put forward for this, ranging from differences in the time in the woman's monthly cycle that sex happens, to the amount of time that sperm spend waiting in the testicles.

The Newcastle study, by Dr Corry Gellatly, is strong evidence that there is a genetic component.

He found that within families, boys with lots of brothers were more likely to have a higher number of sons themselves and those with lots of sisters were more likely to have lots of daughters.

War babies

Dr Gellatly said it was likely that a genetic difference affected the relative numbers of "X" and "Y" sperm within those produced by the man.

This gene, while only active in the man, could be carried by men and women.

"The family tree study showed that whether you're likely to have a boy or a girl is inherited."

He said that the effect was to actually balance out the proportion of men and women in the population.

"If there there are too many males in the population, for example, females will more easily find a mate, so men who have more daughters will pass on more of their genes, causing more females to be born in later generations."

In the years after World War I, there was an upsurge in boy births, and Dr Gellatly said that a genetic shift could explain this.

The odds, he said, would favour fathers with more sons - each carrying the "boy" gene - having a son return from war alive, compared with fathers who had more daughters, who might see their only son killed in action.

However, this would mean that more boys would be fathered in the following generation, he said.

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Evolution Arguments Headed for Islamic World

By Robin Lloyd, LiveScience Senior Editor

The next major battle over evolutionary theory is likely to occur not in the United States but in the Islamic world or in countries with large Muslim populations, because of rising levels of education and Internet access there, as well as the rising importance of biology, a scientist now says.

Like with Christians or Jews, there is no consensus or "official" opinion on evolution among Muslims. However, some of them say that the theory is a cultural threat that acts as a force in favor of atheism, says Hampshire College’s Salman Hameed in an essay in the Dec. 12 issue of the journal Science. This is the same beef that some Christians have with evolution.

However, a general respect for science in the Islamic world means scientists have an opportunity to counter anti-evolution efforts, including the "Atlas of Creation," a glossy 850-page color volume produced by Muslim creationist Adnan Oktar who goes by the name of Harun Yahya. Numerous university scientists and members of the media received copies of this book as an unsolicited gift in 2007.

"There is a standard narrative that science and Islam are compatible, but evolution is one thought that challenges this assumption," Hameed told LiveScience. "It's interesting to see how people respond to it and create their world view in response to that challenge."

Better education, the spread of Internet access and news about U.S. controversies over evolution are provoking some Muslims worldwide to start to ask whether Islam is compatible with evolutionary theory, Hameed said.

"Now is the time that these ideas are going to be solidified. We can shape it. There are positive ways to shape these ideas in which we can avert a mass rejection of evolution," Hameed said.

General confusion

Christian creationists believe God created animals, humanity, Earth and the universe in their original form in six days about 6,000 years ago, a literal interpretation of the Book of Genesis in the Bible. Muslim creationists have similar beliefs, based on the Quran, though they tend to be open to a wider range of interpretations. Scientists say, however, that evolutionary theory (the idea that all organisms evolved from a common ancestor) and the mechanism of natural selection explain the diversity of life on the planet. The theory is well-supported by evidence from multiple fields of study. Evolution not only explains how early primates evolved to become human, but how one species of bird becomes two, and how viruses morph over time to resist drugs.

Scientists can only speculate on where and exactly how life began on Earth, but fossil evidence dates the earliest life to about 3.7 billion years ago.

Hameed’s essay, meanwhile, comes on the heels of an ABC "Nightline" interview this week with President Bush during which he said that he doesn't think that his belief that God created the world is "incompatible with the scientific proof that there is evolution," as well as a Philadelphia Inquirer story quoting EPA Administrator Stephen Johnson as saying he does not think there's a "clean-cut division" between evolution and creationism.

Now, three years after the end of the Dover trial (the upshot: U.S. District Judge John E. Jones barred a Pennsylvanian public school district from teaching "intelligent design" in biology class, saying the concept is creationism in disguise), U.S. residents remain divided on evolution. A Harris poll conducted in November found 47 percent of Americans accept Darwin’s theory of evolution while 40 percent believe instead in creationism.

Scientists worry that those who ignore or dismiss the strong evidence for evolution might also be prone to a worrisome lack of critical thinking, and that over time, support for science and medicine in general could erode.

Muslims and evolution

The Muslim take on evolution diverges somewhat from the classic Christian creationist stance. For instance, Muslims generally accept the scientific evidence that the world is billions of years old, rather than 6,000 years old. Some scholars point to early evolutionary thinking among medieval Muslim philosophers who discussed common descent, Hameed writes. These philosophers, along with Aristotle and others, were among numerous early thinkers to ponder evolution, although people should be "careful in terms of not going overboard" by crediting any of them with coming up with natural selection, the mechanism for evolution that Darwin arrived at, Hameed said.

Still, today, only 25 percent of adults in Turkey agree that human beings developed from earlier species of animals, whereas 40 percent of people in the United States agree with this scientific fact, Hameed writes. And Turkey is one of the most secular and educated of Muslim countries.

Hameed cites data from a 2007 sociological study by Riaz Hassan which revealed that only a minority in five Muslim countries agree that Darwin’s theory of evolution is probably or most certainly true: 16 percent of Indonesians, 14 percent of Pakistanis, 8 percent of Egyptians, 11 percent of Malaysians and 22 percent of Turks.

Nonetheless, evolution is taught in high schools in many Muslim countries, although this is often in a very religious environment, Hameed says. Also, science foundations in 14 Muslim countries recently signed on to a statement in support of the teaching of evolution, including human evolution (it is human evolution that is often the sticking point for Muslims, rather than all evolution, he says).

The solution is for Muslim biologists and doctors to present evolutionary theory as the bedrock of biology and to stress its practical applications, Hameed writes, adding that efforts to link evolution with atheism will defeat efforts to help Muslims accept evolution.

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First brain of Britain: scientists find organ that survived 2,000 years in Iron Age skull

By David Derbyshire

Archaeologists have found Britain's oldest surviving human brain in a field where it was buried 2,000 years ago during the Iron Age.

It was discovered inside a decapitated skull placed in a small pit near York.

Researchers studying the remains believe they could be from a human sacrifice whose head was buried to appease the gods or ward off evil spirits.

Skull

Researchers believe the victim was decapitated as a human sacrifice to appease the gods

Its condition has astonished experts, although further tests are needed to establish why the brain - usually quick to decay after death - is so well preserved.

While soft tissue has been recovered from medieval and Roman skulls, this is the first brain of such antiquity to be found in Britain.

The skull and jaw bone were discovered by archaeologist Rachel Cubitt during an excavation near the University of York.

Wiping away centuries of soil, she felt something rolling around inside. Through the small hole in the base of the skull she saw an unusual yellow substance.

'It jogged my memory of a university lecture on the rare survival of ancient brain tissue,' she said. 'We gave the skull special conservation treatment as a result and sought expert medical opinion'.

The skull was taken to York Hospital, where a CT scanner normally used on living patients revealed a blob of tissue around a third the size of a normal brain with patterns and folds closely resembling a modern organ.

'This brain is particularly exciting'

Dr Sonia O'Connor, a research fellow in archaeological sciences at the University of Bradford who studied the remains, said: 'This brain is particularly exciting because it is very well preserved, even though it is the oldest recorded find of this type in the UK and one of the earliest worldwide.'

The brain appears to come from the late Iron Age - between 300BC and 1BC. Radio carbon dating tests next year should help pinpoint its age, while chemical analysis should reveal why it has survived so well.

Apart from a few vertebrae lying in the pit, the rest of the skeleton was missing.

The researchers believe the victim died by beheading or that the head was cut off soon after death.

skull

A computer-generated scan through the skull show surviving grey matter at the top of the head

Dr Richard Hall, director of archaeology at the York Archaeological Trust, said: 'From the size, it was probably an adult but we can't say whether it was a man or woman.

There is no obvious cause of death because the skull is still intact.

'The skull must have been removed from the body.

'We are confident that the skull was buried in this small pit and that it has lain undisturbed since the Iron Age.'

Dr Hall added: 'It is possible that a living person has been killed and their head put into a pit for some religious purpose.'

The oldest human brain had previously belonged to a Roman who died in Norfolk centuries after the owner of the Iron Age organ died.

Brain tissue has also been recovered from medieval skulls buried in a priory in East Yorkshire.

However, this British brain is a youngster compared with the world's oldest surviving brains, retrieved from nine skulls buried in a Florida swamp around 6,000BC.

How bright was he (or she)?

They may not have left behind pyramids, roads and monuments, but the inhabitants of
Iron Age Britain were far from uncivilised.

And physically, their brains were identical to ours.

By the time Julius Caesar made his first attempt to invade the British Isles in 55BC, Ancient Britons were skilled farmers, construction and metal workers, who had organised themselves into kingdoms the size of modern-day counties.

In the late Iron Age, Britain was a land of small villages, farms and massive hill forts - hill tops fortified with ditches and fences.

york

The skull was found during excavations in the Heslington area of York. The city is rich in cultural history

Most were full-time or part-time farmers, living in family round houses made from wood, mud and thatch and heated with central open fires.

They grew barley and wheat and kept pigs, sheep and cattle.

They had invented querns - or hand-turned millstones to grind cereals into fine flour.

With their metalwork skills they used iron to make knives and ploughs, and bronze and gold for jewellery.

With spindles they span wool, and wove cloth on looms. They used potter's wheels, drove chariots and traded with Europe.

Dr Richard Hall, of York Archaeology Trust, said: 'The British Isles was the bread basket of Europe. The technical skills in manufacturing of bronze and iron were highly skilled.'

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Sarcasm used to diagnose dementia

By Julie Shingleton

SaARCASM may be the lowest form of wit, but scientists are using it to diagnose dementia.
Researchers at the University of New South Wales found that patients under the age of 65 suffering from frontotemporal dementia (FTD), the second most common form of dementia, cannot detect when someone is being sarcastic.

The study, described by its authors as groundbreaking, helps explain why patients with the condition behave the way they do and why, for example, they are unable to pick up their caregivers' moods, the research showed.

"This is significant because if care-givers are angry, sad or depressed, the patient won't pick this up. It is often very upsetting for family members," said John Hodges, the senior author of the paper published in Brain.

''(FTD) patients present changes in personality and behaviour. They find it difficult to interact with people, they don't pick up on social cues, they lack empathy, they make bad judgements,'' he said.

"People with FTD become very gullible and they often part with large amounts of money," he said, adding that one in 4000 people around the world are afflicted with the condition.

Researchers began studying the role of sarcasm in detecting FTD because it requires a patient to spot discrepancies between a person's words and the tone of their voice, Mr Hodges said.

"One of the things about FTD patients is that they don't detect humour - they are very bad at double meaning and a lot of humour (other than sarcasm) is based on double meaning," he said.

The research, conducted in 2006-07, put 26 sufferers of FTD and 19 Alzheimer's patients through a test in which actors acted out different scenarios using exactly the same words.

While in one scenario, the actors would deliver the lines sincerely, in others they would introduce a thick layer of sarcasm. Patients were then asked if they got the joke, Hodges said.

For example, if a couple were discussing a weekend away and the wife suggested bringing her mother, the husband might say: "Well, that's great, you know how much I like your mother, that will really make it a great weekend."

When the same words were delivered sarcastically and then in a neutral tone, the joke was lost on FTD patients, while the Alzheimer's patients got it

"The patients with FTD are very literal and they take what is being said as genuine and sincere," Mr Hodges said.

Original here

Perfume vials from Christ's era unearthed in Israel

ROME (Reuters) – A team of Franciscan archaeologists digging in the biblical town of Magdala in what is now Israel say they have unearthed vials of perfume similar to those that may have been used by the woman said to have washed Jesus' feet.

The perfumed ointments were found intact at the bottom of a mud-filled swimming pool, alongside hair and make-up objects, the director of the dig conducted by the group Studium Biblicum Franciscanum told the Terrasanta.net religious website.

"If chemical analyses confirm it, these could be perfumes and creams similar to those that Mary Magdalene or the sinner cited in the Gospel used to anoint Christ's feet," Father Stefano de Luca, the lead archaeologist, told the website.

Mary Magdalene is cited in the New Testament as a steadfast disciple of Christ from whom seven demons were cast out. She is often considered the sinner who anointed Jesus' feet.

"The discovery of the ointments in Magdala at any rate is of great importance. Even if Mary Magdalene was not the woman who washed Christ's feet, we have in our hands 'cosmetic products' from Christ's time," De Luca said.

Magdala was the name of an ancient town near the shores of the Sea of Galilee in what is now northern Israel. A Palestinian Arab village stood near the site until the war at Israel's establishment in 1948, and an Israeli town called Migdal now occupies the area.

"It's very likely that the woman who anointed Christ's feet used these ointments, or products that were similar in composition and quality," De Luca said.

Studium Biblicum Franciscanum supports research in biblical studies but focuses on archaeological excavation of sites linked to the New Testament and early Christianity in the Middle East.

(Writing by Deepa Babington, editing by Tim Pearce)

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GE Launches Incandescent-Shaped CFL Bulb

The year of unsustainability

We will see whether business and governments are serious about sustainability, says Daniel Franklin


Steve Carroll

For business, the buzzword of 2008 was “sustainability”. Never properly defined, it meant different things to different people, which of course added to its charm. In part it was a new way of packaging the clumsy old “corporate social responsibility” (CSR). And it added a virtuous green dimension: sustainable business would help to save the planet. So companies appointed chief sustainability officers and printed (or, to avoid felling more rainforest, electronically distributed) sustainability reports full of photographs of green fields and blossom.

But that was then. In 2009 sustainability will take on a new meaning in boardrooms: staying in business. As recession bites and growth slows, bankruptcies will soar. To sustain profits, companies will slash costs and cut jobs, while consumers will be even less prepared to pay extra for organic food or air-travel offsets.

In these harsher circumstances many companies will tone down their loud green initiatives and instead quietly emphasise value for money. The budgets for worthy projects in the developing world, let alone for supporting opera houses, will be trimmed or cut altogether as their champions find the spending impossible to defend amid the lay-offs. Even the easy wins in the sustainability business—saving both money and the planet by cutting energy usage—will be less rewarding with lower oil prices.

The good, the bad and the ugly

Some of this will be salutary. In the face of the fashion for CSR, companies have tended to make two mistakes. First, they have been too defensive about the benefits they bring to society by the simple fact of being in business. They provide employment, as well as the goods and services that their customers want—and the threat of job losses and even bankruptcies will serve as a powerful reminder of this basic reality.

Second, many companies pretend that their sustainability strategy runs deeper than it really does. It has become almost obligatory for executives to claim that CSR is “connected to the core” of corporate strategy, or that it has become “part of the DNA”. In truth, even ardent advocates of sustainability struggle to identify more than a handful of examples. More often the activities that go under the sustainability banner are a hotch-potch of pet projects at best tenuously related to the core business. The coming shake-out will help to remove some of this froth.

Yet it would be wrong for companies to conclude that they can forget about trying to be good. The forces that have pushed companies to fret about sustainability—the scrutiny from the internet, multiplying lobby groups, popular concern about global warming, the threat of lawsuits for misbehaviour on human rights—are not about to disappear. Nor will the desire of potential recruits to work for companies with “values” suddenly vanish. In the competition for the best business-school graduates and other high-flyers, especially once the economy starts to recover, companies that show that they were not mere fairweather friends of sustainability will be at an advantage.

And if companies are not seen to take their social responsibility seriously, governments will intervene to change the rules by which they operate. Some will force companies to sell greener products (for example, by banning the sale of incandescent light bulbs). Others will legislate on executive pay, or oblige banks to lend money in ways the state deems desirable. After rescuing the financial system, many Western governments will imagine that they are the best judges of how to run businesses responsibly.

Yet in 2009 governments face their own test on “sustainability”. A summit in Copenhagen at the end of the year is supposed to hammer out a post-Kyoto agreement to cut greenhouse gases. Already pressure is growing to avoid the growth-inhibiting restrictions needed to meet ambitious carbon-cutting targets. Failure to reach a deal will mean, in effect, that the world gives up seriously seeking to stop global warming (see our special section on the environment). Instead, attention would turn to ways the world might adapt to climate change rather than prevent it.

Governments and businesses alike have talked up their commitments to sustainability in recent years. In 2009 both will have to show whether they really meant it.

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People paid to live among trees

By Nigel Morris and Andrew Grice in Brussels

The £100m drive to save the world's forests aims to pay people in developing countries to live among the trees rather than cut them down.

Forest communities will be urged to use the trees to produce rubber or medicine – or to switch to farming or fishing. Amid alarm over the pace of deforestation, new palm oil plantations will be established on ground where trees have already been cleared.

Governments in developing countries will be given help to step up their patrols against illegal logging and offered subsidies towards forest conservation projects. They will also be encouraged to create "buffer zones" around endangered woodlands which loggers are forbidden to cross.

The £100m initiative will be announced by the Government today at the United Nations conference on climate change in Poznan. The cash will be paid in the form of grants or loans to those developing-world governments which submit the most innovative schemes for protecting forests.

Douglas Alexander, the International Development Secretary, told The Independent that the move was a "practical demonstration of our commitment to take practical action to tackle climate change".

He added: "If we are going to have an effective response to dangerous climate change, then it's vital that tackling deforestation is part of the answer."

He warned that global warming was affecting parts of the world least equipped to deal with it. "In the UK we tend to talk about climate change as a future threat," he said. "But what I have learnt is that in the developing world it's a contemporary crisis. The countries that have contributed least to global emissions are most commonly the countries affected worst."

Ed Miliband, the Energy and Climate Change Secretary, said: "They are doing an environmental service to the world by reducing deforestation and therefore it is right we find a means of financing it," he said.

As EU leaders gathered for a two-day summit in Brussels yesterday, Italy and Poland threatened to veto a deal to combat climate change. Under an outline deal reached last year, the EU pledged to cut its greenhouse gas emissions by 20 per cent by 2020, rising to 30 per cent if a global replacement for the Kyoto accord is signed next year. But the EU has failed to agree how to share the burden of the cuts, with Germany, Italy and eastern European nations worried about the impact on their industrial sectors.

The EU's deadline for a deal is the end of this month and diplomats said that a decision would go "up to the wire" when the summit resumes today.

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MIT research looking for cheaper, more abundant solar cell materials

By Rick C. Hodgin

Boston (MA) - Research teams at MIT are taking a new look at solar energy. They're trying to figure out a way to use the Earth's most abundant elements to create inexpensive solar grids capable of generating terawatts of power. The idea is simple: Make solar cells more affordable using readily available materials and the market will naturally migrate over.


30-500-10

The team's research is well underway - even heading toward commercial application. They began by choosing 30 of the Earth's most abundant elements as their starting point. They then worked backwards from the 500 or so compounds those elements are typically found in. They wanted to figure out which of those compounds could be used to harness solar energy. In the end, about 10 promising compounds were selected for detailed study, which is currently ongoing.

The first material chosen was cuprous oxide (Cu2O), a reddish mineral often found in pigments and fungicides. According to Tonio Buonassisi, assistant professor on the project, "[Cuprous oxide] is promising, the optical properties are just right. But the electrical properties are not up to snuff." The team has been attempting to improve its electrical properties with defect engineering methods (those which inject anomalies into the material which alter its electrical properties). At the same time, the remaining candidate compounds are being examined.


Return on investment

According to an interview with Jerry Woodall, Purdue professor with expertise in solar technologies, the break-even point for any kind of alternate energy source (including solar) is 15% efficiency. According to Woodall, no matter how inexpensive it is to produce, if it's not at least 15% efficient, then it's not worth the effort - for a commercial endeavor that is.

Still, the key goal of MIT's research is to reduce production costs of the material itself. If the team can find a suitable replacement for the expensive "highly purified silicon," which is used to create traditional solar cells today, then the effort will have paid off.


Multi-crystalline form

The team has also examined how to replace the expensive single-crystal silicon used today with the much less expensive multi-crystalline silicon. They've been looking to find a correct temperature profile for a re-reheating the silicon after it is initially grown and cooled, a process called annealing.

Multi-crystalline silicon is not very efficient for use in solar cells as its many defects absorb the converted energy. The team has discovered that annealing can greatly reduce the defect's absorption rate, even by a hundred-fold, making multi-crystalline a possible inexpensive alternative without switching compounds.

The report also notes that much of this research is already behind them and production is in advanced stages. Full details of these findings appeared in a Fall issue of Applied Physics Letters. And currently, the team is already working with manufactures to bring products based on their work to the market. According to the report, "Pilot runs are expected within a year [by the end of 2009], and full-scale production soon thereafter." If true, inexpensive multi-crystalline silicon-based solar cells could be available to the public in 2010.


Previous solar research

MIT has been focused on solar cell research for many years. Their report includes citations for scientists dating back to the 1950s. And, as recently as late 2007, MIT scientists began creating a commercial endeavor to pursue a previous invention, called string ribbon solar cells. They received $12.4 million in funding this past March to continue their string ribbon effort. Additional significant advances in reflective materials, and solar cells with a special coating applied which enable them to receive 90% of the sun's energy without moving to track the sun's arc through the sky.

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