Wednesday, January 28, 2009

Space Station Astronauts Lose Bone Strength Fast

By Tariq Malik

Astronauts that spend long months aboard the International Space Station lose bone strength faster than previously thought and have a higher risk of breaking their hips later in life, a new study reports.

A survey of 13 space station astronauts found that their bone strength dipped by at least 14 percent on the average during their half-year stays aboard the orbiting laboratory.

Three of the astronauts lost up to 30 percent of their bone strength during their long-duration spaceflights, putting them on par with the bone strength of older women with osteoporosis on Earth, the study reported.

"If preventive measures are not taken, some of our astronauts may be at increased risk for age-related fractures decades after their missions," said study leader Joyce Keyak, an orthopedic surgery and biomedical engineering professor at the University of California, Irvine.

Keyak and colleagues at UC San Francisco and the Universities of Space Research Assn. in Houston used a new computer program designed to examine the risk of hipbone fracture in people with osteoporosis to analyze hipbone scans of one female astronaut and 12 male astronauts.

Past studies have found that an astronaut's bone mineral density can decrease by between 0.4 percent and 1.8 percent each month. But Keyak's investigation found the drop in bone strength, between 0.6 percent and 5 percent each month, to be substantially greater.

The NASA-funded research is detailed in the online version of the science journal Bone.

NASA has long known that astronauts in space gradually lose muscle strength and bone density over time while on long-duration spaceflights because their bodies float in microgravity, rather than work against the tug of Earth's gravity each day.

To lessen the effects, space station astronauts must exercise at least two hours every day and undergo weeks of rehabilitation after their return to Earth.

The hip and spine of long duration astronauts typically experience the greatest amount of bone loss, researchers said. Hip fractures nearly always require hospitalization or major surgery, while vertebra fractures in the spine can lead to loss of height, severe back pain and deformity, they added.

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It's snowing on Mars ...

Ian Sample

Cape St Vincent, Mars

Cape St Vincent, one of the cliffs of the Victoria crater. Photograph: Nasa/Reuters

High in the sky above Mars, it is snowing right now. Very gently snowing. The snow does not settle on the rubble-strewn land below - not these days, anyway - but instead vaporises into the thin atmosphere long before it reaches the ground.

The first flakes of snow, on a planet that until fairly recently was believed to be waterless, were spotted just a few months ago. A Nasa lander near the planet's north pole was scanning the sky with a laser when it noticed the telltale signs of snowfall. The probe, called Phoenix, announced the news in a radio signal that was picked up by an overhead orbiter and beamed back to Earth. Nothing like it had ever been seen before.

The news of snow falling is just one piece of an extraordinary wealth of information that has recently been sent back from Mars by orbiters, landers and rovers. Together, they have mapped the surface in unprecedented detail, cracked open rocks, sniffed the atmosphere and dug down into the soil. What they have found points to an unimagined Martian history, one where life may have once gained a foothold and may even cling on still in the frigid soils of the permafrost.

Mars is a planet where scale is redefined. It is half the size of Earth, but home to what is probably the largest mountain in the solar system, the 16-mile-high Olympus Mons. Just beneath its equator is a truly grand canyon that also sets a solar system record. The Valles Marineris is as long as the US is wide, and in places reaches 10km deep.

The dream that refuses to die is that one day humans will climb Olympus Mons, and descend into Marineris. But in the meantime, a different sort of exploration is going on - less glamorous, but arguably far more revelatory. Earlier this month, Nasa celebrated the anniversary of the landing of two rovers that were sent to opposite ends of the planet exactly five years before, to study its ancient equatorial geology. The rovers, Spirit and Opportunity, were designed to survive the harsh environment for just 90 days, but somehow they have survived, and they continue to astound Nasa scientists with the new data they send home.

Spirit has explored a world as fantastic as any imagined by JG Ballard. It touched down a short distance from the Columbia Hills in a region named Home Plate, a plateau 80 metres wide. Spirit found the plateau to be surrounded by deposits of opal. As the rover trundled around, its wheels kicked up soil rich in sulphate. Together, these two pieces of information identify Home Plate as an old volcano. "If you were here billions of years ago, it would be exploding, fire-fountaining, with ash coming up and shallow pools of hot water evaporating into the Martian atmosphere," says Ray Arvidson, deputy principal investigator on the rover mission at the University of Washington in St Louis. Warmth and water rank highly on Nasa's checklist of criteria for the emergence of life, and scientists have been making a credible case for water on Mars since at least the mid-1970s, when pictures sent back from the Viking orbiters showed deep channels, canyons and even features that resembled ancient lake shorelines. In 2006, Nasa had announced the then strongest evidence yet for liquid water on the planet, when its Mars Global Surveyor orbiter spotted what appeared to be stains on gully walls caused by gushing water.

On the other side of the planet, Spirit's twin, Opportunity, has been having its own solar-powered adventures, driving around and analysing rocky features on an expanse called the Meridiani Planum. From data sent back to Earth, scientists know that the rover landed on several hundred metres of sedimentary deposits that must have formed in ancient lakes. The soil is inhospitable, similar to that in parts of Rio Tinto in southern Spain, where water bubbles up through iron sulphide deposits, forming sulphuric acid that dries into an acidic mud over the long, dry summer.

The rovers are guided across the Martian landscape by a team of 14 drivers based at the Jet Propulsion Laboratory in Pasadena, California. They arrange their working day to coincide with the Martian night, so they can work out the details for the next day's excursions while the rovers are asleep. The Martian day is 40 minutes longer than on Earth, so the team is constantly shifting the hours it works.

Before shutting down each night, the rovers send pictures and other data of their positions to an orbiter called Mars Odyssey, which relays them back to mission control. There, the drivers confirm the rovers' locations and decide where to send them next. When the rovers wake up, they receive a day's worth of commands telling them what direction to drive in and for how long. All of the moves are run through a simulator on Earth to ensure the rovers won't crash into any boulders or drive off the edge of a cliff.

The process is arduous but it is the only way to drive a golf cart-sized buggy around a planet 100m miles away. Because the driving instructions are relayed via Mars Odyssey, they can take between 1½ hours and a day to reach the rovers.

Remarkably, though long out of warranty, Spirit and Opportunity are carrying only a few mechanical injuries. Spirit, which parked up for the Martian winter with its solar panels angled towards the sun, has recently been ordered to drive south to investigate what look like once-exploding volcanoes that have since been eroded. Opportunity has scrambled out of the 800m-wide Victoria crater and is now setting off on a journey of more than a kilometre to a giant crater called Endeavour. The rocks scattered around the basin of the Endeavour crater have been scanned by cameras aboard orbiters hurtling overhead. They are unlike anything scientists have seen before.

Despite intense radiation (unlike Earth, Mars has no magnetic field to deflect particles spraying out of the sun) and temperatures that dip below -95C, the rovers keep going. So far, they have sent back a quarter of a million pictures from Mars and 36 gigabytes of scientific data.

While Spirit and Opportunity poked and prodded rocks dating back billions of years, the Mars Phoenix lander was sent to explore more recent conditions on the planet. The probe touched down after a flawless descent in the Martian arctic last year, in an area known as Vastitas Borealis, or "northern waste".

On arrival, Phoenix's lead scientist, Peter Smith, of the University of Arizona, expected the lander to find precisely what Spirit and Opportunity had already seen: a landscape smothered in acidic, salty soils that could hardly be considered hospitable. There was good reason to think as much: the planet is frequently hit by giant dust storms that can measure thousands of kilometres wide. When they strike, they whip up the soil and scatter it around on a global scale. The soil in one place, scientists thought, would be similar to that in another.

But built into Phoenix was a robotic arm that allowed it to reach down and gather clods of Martian soil to test with its onboard chemistry lab. And as Phoenix's arm scraped away at the frozen surface, it revealed clear patches of ice that quickly evaporated, making it the first probe to touch water on another planet.

On closer inspection, it became clear that the soil at Phoenix's feet, in the planet's arctic circle, was very different to that found by Spirit and Opportunity at the equator. It was slightly alkaline, like sea water, and contained calcium carbonate, which usually forms in the presence of water. "It told us that Mars is not the same everywhere, as people were suggesting," says Smith. "If the soil was acidic and salty everywhere, you would have trouble imagining life even getting started in a place like that, but we found conditions much like those you see in the Earth's oceans, and for those of us looking for habitable zones on Mars, that's good news."

Scientists poring over data coming back from Phoenix are using it to work out what may have happened in the planet's past. Their best guess links the soil conditions to wild swings in the planet's orientation.

As the Earth orbits the sun, it leans over on its axis at an almost constant 23.5 degrees, and in doing so underpins the regularity of our seasons. Today, Mars is leaning over at around 25 degrees, but five million years ago, that could have been 40 or even 50 degrees. By showing more of its polar caps to the sun, the Martian ice will have warmed up and vaporised. The atmosphere would have become thick with ice clouds that later released snow, which fell to the ground and made the ground damp. That, at least, is the leading theory.

Further tests by the Phoenix lander found traces of a substance called perchlorate in the Martian soil. On Earth, some microbes use perchlorate as a source of energy, Smith says. The picture that emerges from Phoenix is that millions of years ago, when Mars was tilted more toward the sun, the planet may have been hospitable to life. Whether it remained so for long enough for primitive life to get started is another matter.

"We have nutrients in the soil, energy sources, and if there was liquid water five millions years ago, we're getting close to an environment where life could live," says Smith. "If you tossed some Earthly life up there that hadn't evolved for the climate, then it probably couldn't survive. But you have to wonder if, over a long period of time - say a billion years - if Mars slowly transformed itself from a more benign place to what we see today, whether little creatures could have evolved and maybe learned to survive. Life does amazing things on Earth. You can unfreeze the permafrost in Siberia and bring things back to life that have been encased in ice for a million years, so who knows?"

Last week, the evidence for life on Mars received another boost, when scientists at Nasa reported enormous plumes of methane emanating from the planet's north during the summer months. Methane is not proof of life - it can just as well be released by geological processes - but the prospect that life might be responsible is tantalising none the less.

Nasa lost contact with the Phoenix lander on 2 November last year, after it had sent back 25,000 images from the planet. The probe died, or perhaps went into hibernation, when a dust storm darkened the sky and blocked light from reaching the lander's solar panels. The probe's batteries are now drained, and there is only a minute chance that it will power up when the sun is high in the sky again later this year.

In Arizona, Smith's team is turning its attention to an unsolved puzzle in the Phoenix data. Ironically, the presence of perchlorate in Martian soil ruined the probe's chances of detecting organic molecules, which would surely be there if life is present. By testing Martian soils concocted in the lab, and comparing the results with those from Phoenix, Smith believes he may answer the question yet.

Arvidson, who was on the Phoenix team and continues to work on the Nasa rovers, says the evidence from the latest missions points to a Mars that at least in the past could well have supported life. "We've been to three locations and each has its own story of water interacting with the surface and beneath," he says. "The question now is, was it habitable for long enough for life to synthesise and establish an ecosystem? We're paving the way to answer that question, for the future missions that will really dig in and look for the smoking gun."

Mars: the facts

Mars is the fourth rock from the sun and our outer neighbour in the solar system.

Mars has two moons, named Phobos and Deimos, Greek for "fear" and "panic". They were named after the horses that pulled the chariot of the Greek war god Ares.

Mars is nearly half the size of Earth but around one tenth the mass.

Mars and Earth have the same land surface area.

The gravity on Mars is a third of that on Earth.

The Martian year lasts 687 Earth days, and each Martian day is 40 minutes longer.

The Martian atmosphere is 95% carbon dioxide, 2.7% nitrogen and 0.13% oxygen.

Mars has no magnetic field, so the surface is constantly bombarded by radiation from the sun.

What's next?

2009 - Phobos-Grunt

A Russian mission to the Martian moon, Phobos, to bring back soil samples.

2011 - Mars Science Laboratory

A Nasa rover twice the size of the Spirit and Opportunity probes. It will collect and analyse rocks and soil. Chief among its objectives is to find organic compounds and to check for environmental conditions that could have supported microbial life now or in the past.

2013 - Maven

A Nasa orbiter designed to look at gases being given off from the Martian atmosphere.

2016 - ExoMars

A European Space Agency mission to send an orbiter and rover to look for Martian life and possible surface hazards for future manned missions.

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First View of the Dark Side of the Sun

By Clara Moskowitz


Soon we may get the first ever glimpse of the dark side of the sun.

Well, no, there's no actual dark side of a luminous ball of burning gas, but there is an effective dark side, as in, the side of the sun we can't see at any given time.

Scientists aren't content to get just half of the picture, so they've launched the STEREO (Solar Terrestrial Relations Observatories) mission, a pair of NASA spacecraft that will orbit the sun simultaneously to provide a complete view of all sides of the star at once.

"Then there will be no place to hide and we can see the entire sun for the first time," STEREO project scientist Michael Kaiser of NASA's Goddard Space Flight Center told

The perfect spherical view will come on Feb. 6, 2011. Right now the satellites, which were launched in October 2006, are about 90 degrees apart, which allows a picture of about 270 degrees of the sun — the fullest view yet.

"The who goal of all of this is to try to get a better handle to try to predict solar storms, which cause cell phone disturbances, and disruptions to communications and power." Kaiser said. "We'd like to be able to predict these things as far in advance as possible to give us a longer warning time."

Solar storms are magnetic disruptions on the sun that release violent sprays of charged particles into space. These storms can produce magnificent displays of the Northern Lights. But some past storms have also cost airlines and satellite communications industries millions of dollars, and have led to large scale power blackouts (including one across the entire province of Quebec, Canada). Being able to reliably forecast these tempests in advance could make a huge difference in preventing disturbances on Earth.

Predicting solar weather is also important for the future of manned spaceflight. If astronauts are exposed to the intense radiation from solar storms while traveling beyond the protective magnetic field of the Earth, they could suffer serious harm. Even astronauts close to home who venture out for a spacewalk during a storm are put in danger.

"For future missions going to the moon and Mars, that's very important," Kaiser said. "Some of these solar storms can be very intense. If the astronauts were completely exposed to one of these storms the radiation could be high."

The STEREO mission also aims to improve our basic scientific understanding of the dynamics within the sun, which could shed light on the workings of stars in general.

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Strange Asteroid 2009 BD Stalks the Earth

Written by Ian O'Neill

2009 BD is approximately 400,000 miles from Earth (NASA)

The stalker watches us from afar. 2009 BD is approximately 400,000 miles from Earth (NASA)

A 10 meter-wide asteroid named 2009 BD discovered earlier this month is making a slow pass of the Earth, coming within 400,000 miles (644,000 km) of our planet. The near-Earth asteroid (NEO) poses no threat to us, but it is an oddity worth studying. Astronomers believe the rock is a rare "co-orbital asteroid" which follows the orbit of the Earth, not receding more than 0.1 AU (15 million km) away. It is stalking us.

On looking at the NASA JPL Small-Body Database orbital plot, it is hard to distinguish between the orbital path of the Earth and 2009 BD, showing just how close the asteroid is shadowing the Earth on its journey around the Sun

In 2006, NASA announced that Earth's "second moon" was an asteroid called 2003 YN107 (with a diameter of about 20 meters) and it was about to leave the vicinity of Earth, leaving its "corkscrewing" orbit around our planet for seven years, only to return again in 60 years time. 2003 YN107 was of no threat (and wont be in the future), but it is interesting to study these bodies to understand how they interact with Earth. Having NEOs in stable orbits around the Earth could be of benefit to mankind in the future as missions can be planned, possibly sending mining missions to these rocky visitors so we can tap their resources.

The orbital path of 2009 BD (blue line) (JPL Small Body Database)

The orbital path of 2009 BD (blue line) (JPL Small Body Database)

So far, little is known about the new 10 meter asteroid in our near-Earth neighbourhood, but it provides us with an exciting opportunity to track its laborious orbit to see whether it will eventually be ejected after making a close pass to the Earth's gravitational field (as was the case with 2003 YN107 in 2006). From preliminary observations, 2009 BD is projected to shadow our planet for many months (possibly years) to come. Until November 2010 at least, the asteroid will hang around the Earth, within a distance of 0.1 AU.

It is worth emphasising that 2009 BD is of no threat to the Earth, its closest approach takes it 644,000 km from us. For comparison, the Moon's apogee is 400,000 km, so 2009 BD is stalking us from afar, beyond lunar orbit.

As time goes on, astronomers will be able to track 2009 BD's orbit with more precision (for updates, keep an eye on the JPL Small-Body Database), but for now, we have a micro-second moon following the Earth on its orbit around the Sun…

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Truck-mounted laser shoots down spy drone

by Paul Marks

Uncrewed drones have become popular with armed forces around the world and they are tricky to defend against, but a truck-mounted laser that can shoot them down could dilute their usefulness (Image: Boeing)

Uncrewed drones have become popular with armed forces around the world and they are tricky to defend against, but a truck-mounted laser that can shoot them down could dilute their usefulness (Image: Boeing)

Uncrewed aerial vehicles are "revolutionary" technology that America must invest more in. Not the military's view, but that of President Obama in a statement on his defence priorities.

But a technology designed to make UAVs history is already showing promise – aerospace firm Boeing reports that their prototype truck-mounted laser has shot down a UAV at a missile range in New Mexico.

Uncrewed aircraft are powerful tools because they remove pilots from harm's way and because they can be built smaller than conventional spy or combat planes, making them harder to knock out of the sky.

UAVs come in all shapes and sizes: from the hand-launched Aerovironment Raven surveillance plane to the small airliner-sized Global Hawk.

Track and destroy

The Laser Avenger is an infrared laser with power levels somewhere in the tens of kilowatts range mounted on a Humvee off-road vehicle. It is designed to take down the smaller variety of UAV, which are hardest for conventional air-defence weapons to target.

The power of its laser has been doubled since 2007, when it was shown off destroying a stationary improvised bomb. Now it has tracked three small UAVs – the exact model has not been given – and shot one of them down. The laser tracks an object and holds fire until the target is close enough for it to cause burning with a single blast.

Late last year, an airborne laser carried by a modified 747 destroyed its first target, albeit from the ground, using an IR laser in the megawatt range.

Marc Selinger, a Boeing spokesman based in Crystal City, Virginia, won't say at what distance this was achieved, saying it was "an operationally relevant range". The feat is all the more important, he says, because the tracking was achieved against the complex, cluttered visual background of the New Mexico mountains and desert scenery.

Defence boost

The Laser Avenger is a modified version of an existing US Army air defence system that uses two Stinger missile launchers and a heavy machine gun, with one missile pod swapped for the laser and its target tracker. "If funded by the Pentagon, the Laser Avenger could be available within a year," says Selinger. Boeing has so far funded the project itself.

Surface to air missiles designed to target normal-sized aircraft struggle to lock onto small, light, UAVs sometimes made from plastics rather than metal, Nick Brown, editor-in-chief of the journal International Defence Review told New Scientist. "Lasers are a natural extension of their capability."

Firing a laser multiple times would also be cheaper than firing many missiles, and could continue as long as power can be supplied.

However, Brown's colleague Peter Felstead, editor of Jane's Defence Weekly, says the first battlefield lasers will not have UAVs in their sights. "Laser weapons are more likely to be fielded first to counter rockets and mortars, and that capability is not that far away," he says.

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Charity appeal: how brain scans show the trauma of war

By Richard Gray

Combat stress - British troops in Afghanistan in 2007
Feeling the pressure: British troops in Afghanistan in 2007 Photo: PA

For the Ancient Greeks, it was a "divine madness" that infected the minds of soldiers. During the US Civil War, it became known as "soldier's heart". By the First World War it was called shell shock. Today, the condition is known as Post-Traumatic Stress Disorder.

The idea that war can inflict deep and lasting psychological wounds is not new. In Sophocles's tragedies, former soldiers descend into a state of mind that would be all too familiar to modern military psychiatrists. Yet despite the passage of more than 2,400 years, our understanding of PTSD has remained surprisingly unsophisticated: not only are the underlying biological and psychological causes poorly understood, but it is almost impossible to predict which soldiers are the most susceptible.

Now, however, new research from America – triggered by the soaring incidence of PTSD among troops returning from Iraq and Afghanistan – has found striking differences in the brain patterns of those suffering from combat stress, raising hopes that we will be able to identify and treat sufferers much more effectively.

At the most basic level, PTSD is the result of a breakdown in the defence system that copes with traumatic and frightening experiences. After such events, most people will suffer what is known as Acute Stress Disorder, which involves symptoms of anxiety and depression. The majority will recover, but a minority go on to develop the chronic mental health problems that characterise PTSD.

"They get stuck in a cycle whereby recollections of a traumatic event are triggered by a particular situation they encounter," explains Professor Simon Wessely, director of the King's Centre for Military Health Research at the Institute of Psychiatry, King's College London. "This triggers the symptoms, and they then try to avoid the situation that triggered the recollections – but that just means that the symptoms get worse the next time they encounter the same situation."

"Those who develop PTSD are not necessarily the most vulnerable," adds Professor Roberto Rona, a lecturer at King's Psychological Medicine and Psychiatry Division. "Ideally, we would want to start treatment as soon as possible by separating those who are going to recover normally and those who will have a problem after a traumatic event."

One way to find them might be to scan the brains of those affected. In 2007, as fighting intensified in Afghanistan and Iraq, cases of PTSD among American military personnel increased by more than 50 per cent. The Pentagon poured money into research – the latest instalment of which has revealed that there are differences in parts of the brains of those with PTSD.

Older studies had linked PTSD to changes in the activity of the amygdala, the area of the brain involved in emotional memory. But Dr Norbert Schuff, of the Veterans Affairs Medical Centre in San Francisco, found using MRI scans that the hippocampus of sufferers, which plays a major role in short-term memory and emotions, had decreased in size. There was also increased blood flow in the prefrontal cortex, the region responsible for decision-making – hyperactivity here is thought to be involved in the excessive reaction to fear. Most strikingly, there was a loss of up to 10 per cent of the grey matter – the nerve cells and blood vessels that make up much of the brain.

What is unclear is exactly why these changes have come about – and whether they are the cause of combat stress, or its consequence. "It is hard to say which comes first," explains Professor Wessely. "Do the changes in the brain cause the symptoms? Or do they occur as an effect of prolonged stress – or is it a result of alcohol abuse or head injuries?"

One possible explanation comes from research which found a link between PTSD and mild brain trauma, suggesting that the condition could in some cases be triggered by mild brain injuries resulting from nearby explosions. But there is another curious piece of the puzzle. While cases of PTSD are common outside the Armed Forces, soldiers should be particularly vulnerable: their jobs place them in frightening situations where they are more likely to encounter the kind of events that can spark psychological problems.

But while around 20 per cent of ex-combatants in the British Armed Forces do suffer some sort of psychological disturbance – hence the need for the work of Combat Stress, one of the three charities involved in the Telegraph's annual appeal, which ends this week – PTSD is only one of a number of conditions. According to official figures – which some campaigners dispute – just 3 per cent of the British troops sent to Iraq or Afghanistan on active duty develop PTSD. The single biggest mental health problem is alcoholism: according to recent studies, 27 per cent of soldiers are heavy drinkers, and 15 per cent are problem drinkers.

This does not make PTSD any less of a problem. Sufferers are plagued with recurring nightmares, insomnia and depression, experiencing high anxiety, mood swings and relationship difficulties. Divorces, unemployment, homelessness and violence become common; vivid flashbacks can lead to panic attacks; and veterans often sink into a cycle of alcohol or drug abuse as they attempt to deal with their symptoms.

But Prof Wessely has found that the very thing that exposes soldiers to PTSD might also help them deal with it: their job. According to his research at King's, group cohesion and firm leadership are critical in reducing the impact of psychological distress.

"You have to remember we are talking about professional soldiers who have been highly trained," he says. "Their training is designed to harden them against the unpleasant nature of war. The military is actually very effective at reducing the risk of PTSD with their training, their professionalism, esprit de corps and morale. War is a stressful business and this all prepares soldiers for that."

The flip side is that the memories that provoke trauma are not necessarily those of gruesome battles or injuries. "The kind of events that affect them are not simply seeing bad things and coming under fire – it is when the rules they have come to expect are somehow broken. It is when errors of omission or commission lead to the feeling they have been let down, or that they have let their comrades down, that mental health problems occur. This is why 'friendly fire' incidents are so psychologically damaging – it violates the soldiers' rules of who is supposed to be shooting at them. They will feel anger at those responsible."

That was certainly the case for James Saunders, a veteran of the Gulf War interviewed by The Daily Telegraph last month. As a 21-year-old in the Royal Artillery, he experienced "friendly fire" from Challenger tanks. No one was killed, but six months later he began to suffer from anxiety and depression, developed a drug habit and ended up in prison. "For years," he says, "I blamed myself for being a poor soldier and weak-minded." Having sought help from Combat Stress, and been diagnosed with PTSD, Saunders recovered, although he still suffers from occasional depression. On Thursday, he will speak about his battle against PTSD alongside Professor Wessely at the Dana Centre in London.

In addition to the research into the causes of PTSD, new treatment is being developed, drawing on neurolinguistic programming, relaxation techniques and even Eye Movement Desensitisation Therapy, which involves following a moving light or object with the eyes, to work through the bad memories. But there are no simple solutions.

"I don't think there are many people who believe PTSD will be solved by simply giving people a drug," says Wessely. "With soldiers, the only really effective way of preventing it would be to not go to war in the first place."

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Genetics Of Popularity: Genetic Influence In Social Networks Identified

Researchers found that popularity, or the number of times an individual was named as a friend, and the likelihood that those friends know one another, were both strongly heritable. (Credit: iStockphoto/Chris Schmidt)

Can't help being the life of the party? Maybe you were just born that way. Researchers from Harvard University and the University of California, San Diego have found that our place in a social network is influenced in part by our genes, according to new findings published in the Proceedings of the National Academy of Sciences.

This is the first study to examine the inherited characteristics of social networks and to establish a genetic role in the formation and configuration of these networks.

The research was conducted by Nicholas Christakis of Harvard, who is professor of sociology in the Faculty of Arts and Sciences and professor of medical sociology at Harvard Medical School, Christopher Dawes and James Fowler, both of UC San Diego.

"We were able to show that our particular location in vast social networks has a genetic basis," says Christakis. "In fact, the beautiful and complicated pattern of human connection depends on our genes to a significant measure."

While it might be expected that genes affect personality, these findings go further, and illustrate a genetic influence on the structure and formation of an individual's social group.

The researchers found that popularity, or the number of times an individual was named as a friend, and the likelihood that those friends know one another, were both strongly heritable. Additionally, location within the network, or the tendency to be at the center or on the edges of the group, was also genetically linked. However, the researchers were surprised to learn that the number of people named as a friend by an individual did not appear to be inherited.

The study included national data (from the National Longitudinal Study of Adolescent Health) for the social networks of 1,110 adolescent twins, both fraternal and identical. The researchers compared the social networks of the identical twins to those of the fraternal twins, and found greater similarity between the identical twins' social network structure than the fraternal twins' networks.

There may be an evolutionary explanation for this genetic influence and the tendency for some people to be at the center while others are at the edges of the group, according to the researchers. If a deadly germ is spreading through a community, individuals at the edges are least likely to be exposed. However, to gain access to important information about a food source, being in the center of the group has a distinct benefit.

"One of the things that the study tells us is that social networks are likely to be a fundamental part of our genetic heritage," says Fowler, associate professor of political science at UC San Diego. "It may be that natural selection is acting on not just things like whether or not we can resist the common cold, but also who it is that we are going to come into contact with."

The findings also illuminate a previously unknown limitation of existing social network models, which had assumed that all members behave as interchangeable cogs. To address these intrinsic differences in human beings that contribute to the formation of social networks, the researchers have created a new mathematical model, called the "attract and introduce" model, which is also explained in this paper and supports the genetic variation of members.

This model creates networks that very closely simulate actual human social networks, and using this model, they found that when someone was placed in any virtual network, they gravitated towards the same place within the network.

Because both health behaviors and germs spread through social networks, understanding how contagions flow through social networks has the potential to improve strategies for addressing public health concerns such as obesity or the flu.

"I think that going forward, we are going to find that social networks are a critical conduit between our genes and important health outcomes," says Fowler.

Fowler and Christakis have also published on other aspects of social networks, such as the spread of obesity, smoking, and happiness.

The research was funded by the National Institute on Aging and the National Science Foundation.

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Male bonding is rife in chimp society too

by Ewen Callaway

Adult male chimps form enduring friendships, maintaining them by grooming each other (Image: John Mitani)

Adult male chimps form enduring friendships, maintaining them by grooming each other (Image: John Mitani)

Everyone needs a best friend, even chimpanzees. A decade-long study shows that nearly all adult male chimps form enduring social bonds with other males, exchanging back scratches, sharing meat, and generally chumming around.

On average these bonds lasted seven years, says John Mitani, a primatologist at the University of Michigan, who observed chimpanzees in Uganda several months a year for 10 years.

The colony, in the jungles of Kibale National Park, is about three times the size of other chimpanzee populations in Africa, but is no more social than others, he says.

For the study, Mitani spent a block of time recording the interactions of a specific adult male chimp, including every individual he interacted with, while noting grooming behaviour. Females tend to leave their colony once they reach maturity and therefore forge fewer social bonds, Mitani says.

As with human friendship, the strongest bonds seemed to be based on mutual respect. Chimpanzees that groomed each other for roughly equal amounts of times tended to stay friends longer.

Brotherly love

Fraternity also played an important role in chimpanzee friendships, Mitani found. Animals that shared a mother were more likely to form lasting bonds than other pairs. However, chimpanzees with a common father weren't any more likely to become buddies.

Nearly every chimpanzee that Mitani tracked formed at least one long-term social bond, and some had multiple "best friends". Out of 35 males, two never formed close friendships with other adults during the study period. However, both found friendship in a younger, still adolescent brother, Mitani notes.

Exactly why chimpanzees form these stable bonds is unknown, Mitani says. It could be that having a best friend boosts reproductive success or survival somehow. But this will require "staying out there to see who does what with whom, and how often, and counting up the babies," he says.

Joan Silk, a primatologist at the University of California in Los Angeles, notes that chimp friendships aren't so different from the baboon she studies.

Equitable grooming and sisterhood seemed to determine friendships among female baboons in Botswana, she says. "These similarities suggest that there are common principles for building strong bonds which extend across species."

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One small step for a man, one giant leap for teleportation

Posted by Dong Ngo

We've still got a long way to go before human beings can be beamed from one place to another Star Trek-style, but on Friday a team of scientists at the University of Maryland achieved, nonetheless, a milestone in teleportation.

According to LiveScience, the university's Joint Quantum Institute for the first time was able to teleport information between two separate atoms across a distance of a meter--about one step for an adult.

The overview of the experiment's setup.

(Credit: LiveScience)

Generally, teleportation works thanks to a remarkable quantum phenomenon called entanglement that only occurs on the atomic and subatomic scale. Once two objects are put in an entangled state, their properties are inextricably entwined. In layman's terms, if they are in entangled mode, what you "see" on one is what you get on the other.

The JQI team set out to entangle the quantum states of two individual ytterbium ions so information embodied in one could be teleported to the other. Each ion was isolated in a separate high-vacuum trap, suspended in an invisible cage of electromagnetic fields and surrounded by metal electrodes.

After that, the experiment worked like this: Single photons from each of two ions in separate traps interacted at a beamsplitter. When both detectors recorded a photon simultaneously, the ions were entangled. At that point, ion A was measured, revealing exactly what operation had to be performed on ion B to teleport ion A's information (see illustration at right).

It's important to note that the achievement is not any form of conventional communication. This is because in teleportation no information pertaining to the original object actually travels to the other. Instead, the information measured from the first object appears on the second object.

The research was supported in part by the Intelligence Advanced Research Project Activity program under U.S. Army Research Office contract.

It looks like the military's interest in teleportation remains strong. Who knows? This might mean we'll catch Osama bin Laden soon.

Dong Ngo is a CNET editor who covers networking and network storage, and writes about anything else he finds interesting. You can also listen to his podcast at E-mail Dong.

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Ten Best Green Jobs for the Next Decade

By: Anya Kamenetz

Ten Best Green Jobs

Illustration by Erika Schneider

Massive investments in clean energy promise to keep farmers, urban planners, and green-tech entrepreneurs in business for the next decade. This guide to sustainability focused career paths will help solar-charge your work life.
"It's time to bail out the people and the planet," says Van Jones, author of The Green Collar Economy: How One Solution Can Fix Our Two Biggest Problems. We agree, and this guide to to sustainability-focused career paths will help retrofit and solar-charge your work life.

Ten Best Green JobsIllustration by Erika Schneider

"It's time to bail out the people and the planet," says Van Jones, author of The Green Collar Economy: How One Solution Can Fix Our Two Biggest Problems. We agree, and this guide to to sustainability-focused career paths will help retrofit and solar-charge your work life.


America has only two million farmers, and their average age is 55. Since sustainable agriculture requires small-scale, local, organic methods rather than petroleum-based machines and fertilizers, there is a huge need for more farmers -- up to tens of millions of them, according to food guru Michael Pollan. Modern farmers are small businesspeople who must be as skilled in heirloom genetics as marketing.

Schools: University of Vermont: Center for Sustainable Agriculture; Stone Barns Center For Food & Agriculture in New York State; University of Oklahoma: Kerr Center for Sustainable Agriculture; Evergreen State College: degree in Sustainable Agriculture.

Related careers: urban gardener; farmers market and CSA coordinator; artisanal cheesemakers; and other food producers.


Modern forestry a complex combination of international project finance, conservation and development. According to the World Bank, a staggering 1.6 billion people depend on the forest for their livelihoods. Foresters help local people transition from slash-and-burn to silviculture--teaching cultivation of higher-value, faster-growing species for fruit, medicine or timber, for examples while carefully documenting the impact on the environment. Deforestation, which causes around a quarter of all global warming, is also likely to be a leading source of carbon credits worth tens of billions of dollars.

Schools: Yale School of Forestry and Environmental Studies; Duke University: Nicholas School of the Environment; University of Michigan: School of Natural Resources & Environment.

Companies/organizations: The Nature Conservancy; New Forests Inc.

Solar Power Installer

Making and installing solar power systems already accounts for some 770,000 jobs globally. Installing solar-thermal water heaters and rooftop photovoltaic cells is a relatively high-paying job--$15 to $35 an hour--for those with construction skills. And opportunities are available all over the United States, wherever the sun shines. Currently over 3,400 companies in the solar energy sector employ 25,000 to 35,000 workers. The Solar Energy Industries Association predicts an increase to over 110,000 jobs by 2016â even more if anticipated tax credits are accelerated.

Companies: Akeena Solar; Sungevity; Sunpower; Full list at

Energy Efficiency Builder Buildings account for up to 48 percent of US energy use and greenhouse gas emissions. LEED, the major green building certification, has over 43,000 accredited professionals. But the cutting edge in efficient buildings goes far beyond LEED. Buildings constructed according to Passivhaus and MINERGIE-P standards in Germany and Switzerland, respectively, use between 75% and 95% less heat energy than a similar building constructed to the latest codes in the US. Greening the US building stock will take not only skilled architects and engineers, but a workforce of retrofitters who can use spray foam insulation and storm windows to massively improve the R-value (thermal resistance) of the draftiest old houses. A study by the Apollo Alliance recommended an $89.9 billion investment in financing to create 827,260 jobs in green buildings -- an initiative supported by the Obama stimulus package, which specifically mentions energy retrofits.

Schools: Arizona State University School of Architecture: Energy Performance Climate-Responsive Architecture; University of Michigan: Alfred A. Taubman College of Architecture + Urban Planning; The Earth Institute at Columbia University.

Massive investments in clean energy promise to keep farmers, urban planners, and green-tech entrepreneurs in business for the next decade. This guide to sustainability focused career paths will help solar-charge your work life.

Wind is the leading and fastest-growing source of alternative energy with over 300,000 jobs worldwide. Turbines are 90% metal by weight, creating an opportunity for autoworkers and other manufacturers to repurpose their skills. According to the American Wind Energy Association, the industry currently employs some 50,000 Americans and added 10,000 new jobs in 2007. Their job board is an excellent place to start looking for opportunities.

Companies: Vestas; Siemens; GE Energy.

Conservation Biologist The granddaddy of diversity, E.O. Wilson, famously called conservation biology -- discipline with a deadline. The urgent quest to preserve the integrity of ecosystems around the world -- and to quantify the value of -- ecosystems services -- leads to opportunities in teaching, research and fieldwork for government, nonprofits, and private companies. The forthcoming economic stimulus package from the Obama administration offers the prospect of increased federal support for science and research.

Schools: Center for Conservation Biology at the University of Washington and the Center for Conservation Biology at Stanford University. At the small College of the Atlantic every student gets his or her degree in human ecology; it's been called the most sustainable college or university in the world.

Green MBA and Entrepreneur

The concept of the triple bottom line has migrated from the margins to the mainstream of the business world. A recent report by the U.S. Conference of Mayors, Mayors Climate Protection Center found that business services like legal, research and consulting account for the majority of all green jobs -- over 400,000. This includes everything from marketing to the LOHAS (Lifestyles of Health and Sustainability) segment, to serving as a VP of sustainability within a large company, to piloting a green startup like Method or Recyclebank.

Schools: Stanford School of Business; San Francisco's Presidio School of Management; Leeds School of Business; University of Colorado at Boulder -- Deming Center for Entrepreneurship; the Bainbridge Graduate Institute in Wash.

Recycler The total number of recycling jobs in the United States is at more than 1 million, according to recent reports (PDF, right click to save). Although the market for paper and plastic has slowed down recently due to the economic downturn, demand for steel is still strong -- 42 percent of output came from scrap in 2006 -- and recycling remains the economical alternative to high disposal fees. Worldwide more than 200,000 people work in secondary steel production, and the US is a major center of production. New laws and regulations are also creating a need for specialized companies that can close the loop by recycling and repurposing e-waste, clothing, plastic bags, construction waste, and other materials.

Companies: Rumpke; Greenstar North America.

Sustainability Systems Developer The green economy needs a cadre of specialized software developers and engineers who design, build, and maintain the networks of sensors and stochastic modeling that underpin wind farms, smart energy grids, congestion pricing and other systems substituting intelligence for natural resources. Coders with experience using large scale enterprise resource planning have an edge here, as well as developers familiar with open source and web 2.0 applications.

Companies: IBM, V2Green, WindLogics

Urban Planner Urban and regional planning is a linchpin of the quest to lower America's carbon footprint. Strengthening mass transit systems, limiting sprawl, encouraging use of bicycles and deemphasizing cars is only part of the job. Equally important is contingency planning, as floods, heat waves and garbage creep become increasingly common problems for metropolises. Employment in this sector is projected to grow 15 percent by 2016, and the jobs are mainly in local governments, which make them a slightly safer bet for the downturn.

Schools: Penn Institute for Urban Research; Harvard: Department of Urban Planning and Design; Portland State University: Nohad A Toulan School of Urban Studies and Planning.

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