Photos from around the world on 27 May
News from around the world this week
Mladic arrested in Serbia
Photos from around the world on 26 May
Ghana's Aboakyer deer-hunting festival
Readers' pictures on the theme of glass
Hundreds flee the Yemeni capital Sanaa
Barack Obama's three-day state visit to the UK
US President Barack Obama in Ireland
Photos from around the world this week
By Pallab Ghosh Science correspondent, BBC News 
Electrons (blue) orbit the nucleus of an atom in this schematic The most accurate measurement yet of the shape of the electron has shown it to be almost perfectly spherical.Electrons are negatively-charged elementary particles which orbit the nuclei of atoms.
The discovery is important because it may make some of the emerging theories of particle physics - such as supersymmetry - less likely.
The research, by a team at Imperial College London, is published in the latest edition of Nature journal.
In their scientific paper, the researchers say the electron differs from being perfectly round by a minuscule amount.
"Conventionally, people think that the electron is round like a little ball. But some advanced theories of physics speculate that it's not round, and so what we've done is designed an experiment to check with a very, very high degree of precision," said lead author Jony Hudson, from Imperial.
The current best theory to explain the interactions of sub-atomic particles is known as the Standard Model. According to this framework, the electron should be close to perfectly spherical.
But the Standard Model is incomplete. It does not explain how gravity works and fails to explain other phenomena observed in the Universe.
Egg off the menuSo physicists have tried to build on this model. One framework to explain physics beyond the Standard Model is known as supersymmetry.
However, this theory predicts that the electron has a more distorted shape than that suggested by the Standard Model. According to this idea, the particle could be egg-shaped.
The researchers used lasers to measure the shape of the electron Researchers stress that the new observation does not rule out super-symmetry. But it does not support the theory, according to Dr Hudson.
He hopes to improve the accuracy of his measurements four-fold within five years. By then, he said, his team might be able to make a definitive statement about supersymmetry and some other theories to explain physics beyond the Standard Model.
"We'd then be in a position to say supersymmetry is right because we have seen a distorted electron or supersymmetry has got to be wrong because we haven't," he told BBC News.
Dr Hudson's measurement is twice as precise as the previous efforts to elucidate the shape of the electron.
Future prospectsThat in itself does not alter scientists' understanding of sub-atomic physics, according to Professor Aaron Leanhardt of Michigan University in the US.
But the prospect of improved measurements and the potential to shed light on current theories of particle physics has made the research community "sit up and take notice".
The Large Hadron Collider is searching for signs of supersymmetry "A factor of two doesn't change the physics community's general opinion of what's going on," he told BBC News.
But he added that improved measurements could start "constraining the possible theories, and what could be discovered at the Large Hadron Collider at Cern and what you might expect in cosmological observations."
Current theories also suggest that if the electron is more or less round, then there ought to be equal amounts of matter and anti-matter - which, as its name suggests, is the opposite of matter.
Instead, astronomers have observed a Universe made up largely of matter. But that is an observation that could be explained if the electron were found to be more egg-shaped than the Standard Model predicts.
Although the shape of the electron could have an important bearing on the future theories of particle physics, Dr Hudson's main motivation is simply curiosity.
"We really should know what the shape of the electron is," he said.
"It's one of the basic building blocks of matter and if this isn't what physicists do I don't know what we should do".
Previous research has shown that decorated webs tend to last longer The delicate web decorations spun by some orb-weaving spiders are a strange but well-known phenomena, but exactly why the spiders adorn their webs is unclear. Now a study by researchers in Australia suggests that the creatures use decorations to protect their webs from damage.
A team has made a discovery in one spider species that suggests the spiders use adornments "tactically" to make their webs more visible to animals that might accidentally damage them.
The findings are published in the journal Behavioural Ecology and Sociobiology.
"When I started studying this behaviour I had no idea that it was such a tricky area," said lead researcher Dr Andre Walter from the University of Melbourne in Australia.
"The debate about [its] function has lasted for over 100 years and is still highly controversial."
Previous research has shown that decorated webs tend to last longer than undecorated ones. But Dr Walter wanted to find out if this protective function was what motivated the spiders to spin their decorations.
He set up plastic frames in his lab, and left a group of orb-weaving Argiope keyserlingi spiders to build their webs in the frames. Once they were finished, the team carried out some controlled damage.
Dr Walter divided the spiders into three groups, left one group's webs alone, "lightly damaged" another group's and carried out heavy damage on another.
Continue reading the main story Studies have suggested that web decorations attract preyDecorations make spiders more visible to predators, so scientists think the local environment - and what types of predators are around - influences how much a spider decorates its webWhen they repaired or rebuilt their webs, the spiders increased their decorating activity following heavy damage but not mild damage, he reported.So he thinks the spiders deliberately make their webs more visible to passing animals that might unintentionally walk into them.
"The spiders tactically use the decorations," he said, "distinguishing between normal web damage that happens every day (when the prey insects hit the web) and unusual damage by unwanted visitors."
Invisible obstacle"Have you ever seen those cross-shaped tapes on brand-new windows?" Dr Walter asked.
"They're to warn us that there's something we might not see.
"The cross shaped decorations in Argiope keyserlingi may work in a very similar manner."
The decorations may draw in prey by reflecting UV light The species his team studied belongs to a group of orb-weaving spiders that permanently live in their webs, sitting in the centre.
"Other orb-weavers build protective retreats where they can hide," explained Dr Walter.
"So damaging or destroying the web for [this species] means costly web repairs or even the risk of losing their home completely."
About one-in-six homes are at risk from flooding, data shows Incentives, such as garden makeovers and fruit and veg vouchers, could help home-owners invest in energy efficiency measures, a pilot scheme has shown.But the study found that more had to be done to convince people of the merits of flood protection devices, even if they lived in high flood risk areas.
The trial by the University of Salford set out to discover if non-cash incentives could change attitudes.
Studies have estimated that 70% of homes in 2050 have already been built.
Experts warn that unless existing homes are "retro-fitted" with energy saving devices, then the UK will not meet its target of cutting CO2 emissions by 80% in the middle of this century from 1990 levels.
Tempting technology
In the small-scale trial, 50 households in Timperley, near Manchester, were offered surveys to assess the houses' energy efficiency and vulnerability to flooding.
They were then offered a selection of non-cash rewards, including public transport season tickets and access to further education courses, if they decided to go ahead and invest in devices to reduce energy use or protect their homes from flooding.
Out of the 50 homes, 25 agreed to have a survey carried out. Five households then went on to have their homes improved, while a further seven were undecided at the time the team produced its interim report.
The trial was funded by the Environment Agency and Trafford Borough Council.
A spokesman for the Environment Agency said that one-in-six homes in England and Wales were at risk from flooding.
Making the switch: Incentives helped people become more energy efficient "The Environment Agency has completed 225 new defences in the past four years, increasing protection to over 198,000 properties, but flooding cannot be entirely prevented," he told BBC News.
"We urge people to check whether their property is at risk by signing up to the Agency's free flood warning service to get free alerts.
"Individuals and businesses can also help make their properties more resistant to flooding using specialised flood products."
Erik Bichard, who led the research team, explained why incentives could have a role to play as a policy tool to improve the take-up of green technology.
"Psychologists have been trying to tell us about how people make decisions for some time, it just has not filtered through to this area," he said.
Professor Bichard said there were five main areas that affected people's decision-making processes:
Understanding the issueCaring about the issueKnowing what to doWill doing something solve the problem?What will people think?He went on to explain how the offer of rewards could influence how people made up their minds.
Continue reading the main storyI probably would never spend money on a garden makeover, I would have kept it for what you might call more practical things”End Quote Barbara Tarbuck Homeowner "Some of these areas are cognitive, intellectual, fact-based reasons, such as: Is there a problem? What can I do about it? Will it work?
"Incentives by-pass a lot of that thinking and take people straight to the question: 'If I do this then will I be better off than before'?"
One of the participants, Barbara Tarbuck, decided to pay for a new boiler to be installed in return for a garden makeover and fruit-and-veg vouchers.
Despite living in a relatively modern home, she explained that she agreed to a survey because she wanted to know what measures were already present in the house.
"I also wanted to see what I could do to reduce energy bills, so I was quite intrigued to see what ideas they came up with," she said.
Mrs Tarbuck also welcomed the idea of offering non-cash rewards: "It is alright to have a little grant to have a little bit to put towards the cost, but I am seeing benefits in two sorts of ways.
"I probably would never spend money on a garden makeover, I would have kept it for what you might call more practical things."
Tough choices
In the trial, all five households that decided to improve their properties all went for energy saving measures, with none choosing to reduce their homes' vulnerability to flooding.
Professor Bichard and his team asked people why they had decided against spending money on flood protection measures.
"About half of the people were put off by the price of flood protection," he said, adding that two door guards and some air brick covers would cost almost ?2,000.
"Although we were proposing to reward back the full amount, the economic situation [meant that] people just did not have that sort of cash in the bank to make that sort of investment."
Mrs Tarbuck was among this group. She explained: "I went for the larger outlay of getting a boiler fitted. I am not saying I will not do it in the future, as I still have the report and what was recommended."
Professor Bichard said that the other half of participants were sceptical as to whether it was necessary to spend the money in the first place.
"They simply did not believe that flooding was ever going to affect their house, even though the Environment Agency's statistics show that they lived in a flood threatened area and they really needed to take responsibility to protect their house.
"That is interesting because even with the amount of incentives that we were offering, it just was not enough to overcome the fourth 'will it work' reservation."
Dean Barr had worked for a Borders estate before taking up a post at Skibo An estate worker had enough illegal poison to "wipe out the entire Scottish golden eagle and red kite populations several times over", a court has heard.Dean Barr, 44, of Clashmore, Dornoch, admitted possessing 10kg of Carbofuran.
The insecticide, banned in 2005, was found in a farm building, used by Barr, on the exclusive Highlands Skibo Castle estate in May 2010.
Sheriff Margaret Neilson fined the former Ulster Defence Regiment soldier ?3,300 at Inverness Sheriff Court.
Despite the find, the Crown accepted Barr had no part in the deaths of two golden eagles and a sparrow hawk found on the estate in May 2010.
The insecticide was discovered in a locked store by police investigating the deaths of the birds. Barr had the keys to the store.
'Foolish omission'The Carbofuran found had been bought by a farmer to legally treat crops on a Scottish Borders estate where Barr had worked.
The court heard that while father-of-two Barr had not purchased the powder, he took it with him - along with other items, from a shed when he took the job at Skibo in 2008.
Fiscal depute Ian Smith said: "The RSPB said this was the largest find of any illegal poison in the UK."
He added: "10kg is sufficient to wipe out the entire Scottish golden eagle and red kite populations several times over.
"Only a few granules are needed to kill a bird of prey."
Defence lawyer David McKie said Barr was aware of the risks Carbofuran posed, but he had not known how to safely dispose of the powder, which was kept in a plastic tub.
A dead golden eagle was found on the Skibo estate on 7 May 2010 Mr McKie said Barr's case was one of "foolish omission" and that his client had been naive and had never used the substance.
However, Sheriff Neilson said it was "extraordinary" that a man of Barr's experience had not known how to legally dispose of Carbofuran and had been prepared to take it 200 miles north from the Borders to the Highlands.
She told Barr that had he been found responsible for the birds' deaths, he would have been facing a custodial sentence.
She fined him ?3,300 for possession of Carbofuran to "mark the court's disapproval".
Later, also at Inverness Sheriff Court, a former apprentice gamekeeper was fined ?1,500 after he admitted possessing a dead red kite.
James Rolfe, 20, who was a gamekeeper at Moy Estate, said he found the bird of prey in a trap set for stoats and weasels but picked it up put the bird in a Land Rover rather than leave it and inform his bosses, the police, or RSPB.
The bird was not poisoned.
RSPB Scotland said it was pleased the sheriff had sent out "a clear message" that society would not tolerate "reckless and deplorable behaviour in the countryside".
Rolfe was found with the dead red kite by police who had arrived on Moy estate with search warrants, issued under the wildlife crimes act on 3 June 2010.
Defence lawyer Iain Fleming said his client was 19 at the time and he had panicked after finding the kite dead in the trap.
Wild reindeer foraging for food on the Arctic islands of Svalbard Arctic reindeer can see beyond the "visible" light spectrum into the ultra-violet region, according to new research by an international team.They say tests on reindeer showed that the animal does respond to UV stimuli, unlike humans.
The ability might enable them to pick out food and predators in the "UV-rich" Arctic atmosphere, and to retain visibility in low light.
Details are published in the The Journal of Experimental Biology.
Seeing predatorsUV light is invisible to humans. It has a wavelength which is shorter (and more energised) than "visible" light, ranging from 400 nanometres down to 10nm in wavelength.
The researchers first established that UV light was able to pass through the lens and cornea of the reindeer eye by firing light through a dissected sample. The tests showed that light down to a wavelength of about 350nm passed into the eye.
Continue reading the main storyHumans and some other mammals are actually a minority in not having UV sensitivity”End Quote Professor Lars Chittka Queen Mary University London They then sought to prove that the animals could "see" the light, by testing the electrical response of the retina of anaesthetised reindeer to UV light.
"We used what is called an ERG (electroretinography), whereby we record the electrical response to light by the retina by putting a little piece of gold foil on the inside of the eyelid," co-author Professor Glen Jeffery of University College London told BBC News.
The tests showed that photoreceptor cells or "cones" in the retina did respond to UV light.
"If you're a bumblebee, you wouldn't think much of what this animal is doing because it's seeing in what's called 'near UV' (about 320 to 400nm), but that's still very high energy stuff."
UV vision might enable reindeer to "see" their traditional predator, the wolf The researchers believe UV vision could enable the reindeer to distinguish food and predators in the "white-out" of the Arctic winter and the twilight of spring and autumn.
Lichen, on which the animal feeds, would appear black to reindeer eyes, they say, because it absorbs UV light. The animal's traditional predator, wolves, would also appear darker against the snow, as their fur absorbs UV light.
Urine in the snow would also be more discernable in UV vision, which might alert reindeer to the scent of predators or other reindeer.
Neither did the animal appear to suffer any damage as a result of seeing in UV, say the researchers, or suffer the "snow blindness" humans can experience in the UV-rich Arctic environment.
Polar visionProfessor Lars Chittka of Queen Mary University London, who has explored the UV capabilities of bees, said the study showed what we call the "visible" spectrum did not apply to most of the animal kingdom.
"It's further evidence that UV sensitivity across animals is the rule rather than the exception, and that humans and some other mammals are actually a minority in not having UV sensitivity," he said.
Professor Chittka was not surprised the UV light appeared to do no damage to the reindeer retina. He said the tests suggested the eye would only admit lower-frequency UV light ("UV-A light") rather than more damaging higher-frequency light ("UV-B").
Further modelling and behavioural tests would also be needed to verify that reindeer's apparent capacity to detect UV light really did result in "better detection of predators and arctic lichens", he said.
The same research team which conducted the reindeer tests will soon repeat the same experiments on seals to see whether they can see into the UV region. Professor Jeffery believes many Arctic animals are likely to have the capacity.
"There's no evidence that Arctic foxes or polar bears suffer from snow blindness, so I bet you that most of the Arctic animals up there are seeing into UV."
Mars collided with relatively few rocky masses, hence its "embryonic" state, says researchers Mars formed in record time, growing to its present size in a mere three million years, much quicker than scientists previously thought. Its rapid formation could explain why the Red Planet is about one tenth the mass of Earth.
The study supports a 20-year-old theory that Mars remained small because it avoided collisions with planetary building material.
The new finding is published in the journal Nature.
In our early Solar System, well before planets had formed, a frisbee-shaped cloud of gas and dust encircled the Sun.
Scientists believe that the planets grew from material pulled together by electrostatic charges - the same force that's behind the "dust bunnies" under your bed.
These proto-planetary dust balls grew and grew until they formed what scientists term "embryo" planets.
These rocky masses were large enough to exert a considerable gravitational force on surrounding material, including other nascent planets.
Nudging each other with their gravitational fields, the embryos were often thrown from their regular orbits, sometimes into the path of another large rocky mass.
If collisions occurred, these nascent planets were either expelled from the Solar System or shattered into pieces. These pieces were often combined to form a larger planet. In fact, the Earth's Moon is thought to be the result of an embryo planet colliding with our own planet.
By modelling this process, astro-physicists can determine the size of planets they expect to form at a given distance from the Sun. Mars is an outlier; it should have grown to around the size of the Earth, but remains about one-tenth its size.
Because of Mars' small size, many scientists have long suspected that the Red Planet avoided the collisions that allowed other neighbouring planets to increase their girth.
Red Runt
By studying the chemical composition of meteorites, geochemist Dr Nicholas Dauphas of the University of Chicago in Illinois and Dr Ali Pourmand of the University of Miami in Florida joined forces to try to confirm this.
By measuring the concentration of elements Thorium and Hafnium in 44 space-rocks Dr Pourmand and Dauphas have come up with the most precise estimate of the time it took Mars to form.
Between 2 and 3 million years they suspect; short compared to the Earth, which is thought to have taken tens of millions of years to grow to its current size.
"We were pleasantly surprised because now we have precise evidence in support of the idea… that Mars is a stranded planetary embryo", Dr Pourmand told BBC News.
He thinks that Mars was around more or less in its current size when the Earth was beginning to form.
Given this, Mars could not have experienced the same type of growth as the Earth and Venus, says Dr Pourmand.
It's likely that Mars remains small because it deftly avoided colliding with other planets.
"The fact that Mars appears to have been left unscathed could just be down to luck," says astrophysicist Dr Duncan Forgan of the University of Edinburgh, UK.
He explains that while it is unlikely that a planet could escape collisions for such long periods, statistically one expects it to happen from time to time.
When modelling planetary dynamics, researchers find it easier to predict what happens in general, he says, but it is much more difficult to determine what happens in specific solar systems, or in specific cases like Mars.
Now researchers say that they intimidate more familiar garden birds.
A team from Imperial College London has evidence that parakeets deter songbirds from using garden feeders.
The team says that reducing or managing the parakeet population "might be beneficial for song birds".
There are now an estimated 31,000 parakeets in the UK - mostly in and around London and south-east England. And the latest "parakeet census" shows that their numbers are increasing at an average of 23% per year.Anecdotal evidence suggests that the UK's only naturalised parrot is becoming an agricultural pest, particularly for fruit-growers in the South East. But this study, led by PhD student Hannah Peck, is the first to apply a scientific method to find out what effect the parakeets have on garden birds.
She and her team looked specifically at feeding behaviour. They set up their experiment in 47 different gardens - putting a caged parakeet on a stand next to a garden feeder and filming the feeder to record what birds came to visit.
The birds flock together and roosting sites, with hundreds of birds, can be very noisy places The scientists recorded the activity at the feeding station when the caged parakeet was present and when an empty cage was on the stand.
"We typically get blue tits and great tits on the feeders and so far the results have shown that they are more reluctant to feed when a parakeet is present," said Ms Peck.
"This is likely to be true for the other small birds too, such as coal tits, long tailed tits, greenfinches and goldfinches, but as we got such small numbers of these other species it will be difficult to tell from our data."
This is the first evidence for a negative impact of the parakeets' presence on native birds and Ms Peck will be presenting her findings at a British Ecological Society meeting on invasive species in June.
Garden parrotThe birds' native patch is in the Himalayas. But their adaptation to the cold - along with the plethora of lovingly topped-up peanut feeders in suburban gardens - appears to be helping them to thrive in the UK.
Ring-necked parakeets have also been introduced elsewhere in Europe. One recent study by researchers in Belgium investigated whether the parrots, which nest in tree cavities, were driving native nuthatches out of those same sites.
Garden birds spent less time at the feeder when the parakeet was present Although they found some competition for the nesting holes, the Belgian researchers concluded that parakeets would have a very limited impact on the country's nuthatch population.
The RSPB points out that there is, as yet, no published evidence to show that UK songbirds are affected by ring-necked parakeets.
Grahame Madge from the RSPB says that house sparrows and starlings are the only songbirds of conservation concern whose ranges overlap with the parakeets. And that they might simply be finding food elsewhere.
"Supplementary feeding for these species may be important," he told BBC Nature. "[But] we believe... insect-rich areas of grass and areas rich in seeds will provide the opportunities they need."
But the fact that they scare garden birds away from feeders is likely to enhance the parakeets' reputation as an invasive menace.
Ms Peck said: "We are not yet in a position to make a fair judgement on how best to manage the parakeet population but we hope that our research over the next couple of years will provide evidence for policy makers to do so."
Ironically, the fact that the population of parakeets is now so high means that it would be very difficult and very expensive to cull them, particularly as they live mainly in urban and suburban areas.
"In the long term, other birds might just get used to the parakeets," said Ms Peck.
Mr Madge concluded: "It is important that the spread of the ring-necked parakeet is monitored, and that studies like this one continue to investigate the potential impacts on our native wildlife."
A full report about the decline in British songbirds will feature on Countryfile on Sunday 29 May, 1900BST, BBC One
Much of the oceanic food web will be affected by pH changes as well as by warming Whether you prefer the term "ocean acidification" or the less compelling but more accurate "ocean de-alkalisation", there's little doubt that the addition of carbon dioxide to the seas threatens to change them fundamentally over the course of the century.Ocean acidification 101 says that the oceans absorb some of the extra CO2 going into the atmosphere.
That slowly makes seawater less alkali - or more acid, as you prefer - with major and potentially catastrophic impacts on sea life.
The science is well documented, so I won't go over that ground again except to raise an alert to look out for an interesting study coming out in the next few days.
If global ocean acidification from global CO2 emissions is the issue, you might think that the solution would necessarily be global as well.
That's certainly the way it's mainly been talked about - and in the long run, curbing carbon emissions probably is the only way to protect the coral and other shell-forming creatures that depend on seawater maintaining a constant average pH around 8.2.
But in an article in the journal Science this week, a group of US-based scientists and lawyers is making a different argument: local initiatives can be effective too, they say.
There are a couple of main strands to their argument.
Firstly, the pH of seawater varies from place to place; and in some coastal zones, it's already been pushed toward the acid by local pollution.
The oceans are thought to have absorbed about half of the extra CO2 put into the atmosphere in the industrial ageThis has lowered its pH by 0.1pH is the measure of acidity and alkalinityThe vast majority of liquids lie between pH 0 (very acidic) and pH 14 (very alkaline); 7 is neutralSeawater is mildly alkaline with a "natural" pH of about 8.2The IPCC forecasts that ocean pH will fall by "between 0.14 and 0.35 units over the 21st Century, adding to the present decrease of 0.1 units since pre-industrial times"Secondly, there's a large and growing mound of evidence to suggest that keeping reefs, for example, safe from disease and destructive fishing and local pollution and invasive species gives them greater resistance to climate-related threats.
A couple of years ago, in sediments around Chesapeake Bay on the eastern US coast, scientists found that the northern quahog - a type of clam whose name will resonate with fans of the Family Guy cartoon series - were in trouble.
The problem was a lack of the calcium carbonate minerals from which they fashion shells.
Putting crushed-up old shells into the sediments raised the amounts available to them, which led to an increase in the number of live clams.
One of the projected impacts of ocean acidification is a decline in the availability of carbonate, which many sea creatures extract to form aragonite and calcite.
So here in Chesapeake Bay, the authors of the Science article suggest, is evidence that localised measures could provide some defence against the global trend.
If that's a science-based approach, laws and regulations may also help.
Enforcing rules on coastal erosion, and the quality of water in rivers running into the sea, can reduce local pollution that's pushing in an acidifying direction, the article argues.
The northern quahog benefited from recycling And they imply that anyone who takes an interest in the issue should scrutinise local laws to see what remedies may be available.
The US, for example, has the Clean Air Act, Clean Water Act, Coastal Zone Management Act and many others at federal and state level that might be deployable.
As discussed here a few weeks ago (and more recently by David Adam in Nature Climate Change), campaign groups have regularly attempted to use legal avenues to force action on emissions - not, it should be said, with a vast amount of success.
The latest case - an intriguing twist - has been brought by Micronesia against plans to enlarge the Prunerov coal-fired power station in the Czech Republic.
Whatever the merits of the case, it's clearly one where lawyers will have ample scope to argue about the limits of jurisdiction, the attribution of climate impacts, and indeed the scale of impacts given that projections of sea level rise are far from accurate.
Lots of the difficulties melt away when local laws are used for local change.
It might not be a strategy that solves the problem - but it could bring some relief to beleaguered bivalves.
The blast may have occurred a mere 520 million years after the Big Bang A cataclysmic explosion of a huge star near the edge of the observable Universe may be the most distant single object yet spied by a telescope.Scientists believe the blast, which was detected by Nasa's Swift space observatory, occurred a mere 520 million years after the Big Bang.
This means its light has taken a staggering 13.14 billion years to reach Earth.
Details of the discovery will appear shortly in the Astrophysical Journal.
The event, which was picked up by Swift in April 2009, is referred to by astronomers using the designation GRB 090429B.
The "GRB" stands for "gamma-ray burst" - a sudden pulse of very high-energy light that the telescope is tuned to find on the sky.
These bursts are usually associated with extremely violent processes, such as the end-of-life collapse of giant stars.
"It would have been a huge star, perhaps 30 times the mass of our Sun," said lead researcher Dr Antonino Cucchiara from the University of California, Berkeley.
"We do not have enough information to claim this was one of the so-called 'Population III" stars, which are the very first generation of stars in the Universe. But certainly we are in the earliest phases of star formation," he told BBC News.
Swift, as its name implies, has to act quickly to catch gamma-ray flashes because they will register for only a few minutes.
Record breakerFortunately, an afterglow at longer wavelengths will persist sometimes for days, which allows follow-up observations by other telescopes that can then determine distance.
It was this afterglow analysis that established another burst in the week previous to GRB 090429B to be at a separation from Earth of 13.04 billion light-years, making it temporarily the "most distant object in the Universe".
The event was picked up in April 2009 by Nasa's Swift telescope This other event (GRB 090423) was reported fairly soon after its occurrence, but it has taken astronomers two years to come back with a confident assessment that an even greater expanse lies between Earth and GRB 090429B.
There are other competing candidates for the title of "most distant object". Hubble, for example, was given much more powerful instruments during its final astronaut servicing mission in 2009, and teams working on new images from the famous space telescope have seen galaxies that look not far short of GRB 090429B - and potentially even further out.
It should be stated, of course, that in these sorts of observations, there is always a degree of uncertainty.
Hubble's targets were galaxies - collections of stars; and GRB 090429B is the signature of a single event, a single star. So, in that sense, it might be considered apart.
Scientists are very keen to probe these great distances because they will learn how the early Universe evolved, and that will help them explain why the cosmos looks the way it does now.
They are particularly keen to trace the very first populations of stars. These hot, blue giants would have grown out of the cold neutral gas that pervaded the young cosmos.
Brilliant but briefThese behemoths would have burnt brilliant but brief lives, producing the very first heavy elements.
Their intense ultra-violet light would also have "fried" the neutral gas around them - ripping electrons off atoms - to produce the diffuse intergalactic plasma we still detect between nearby stars today.
Continue reading the main story
Models assume GRBs arise when giant stars burn out and collapseDuring collapse, super-fast jets of matter burst out from the starsCollisions occur with gas already shed by the dying behemothsThe interaction generates the energetic signals detected by SwiftRemnants of the huge stars end their days as black holesSo, apart from its status as a potential record-breaker, GRB 090429B is of intense interest because it is embedded directly in this time period - the "epoch of re-ionisation", as astronomers call it.Whether GRB 090429B was one of the very first stars to shine in the Universe is doubtful, as Dr Cucchiara states. There may be several generations before it.
But Swift will keep looking, and it is ideally suited for the purpose, explains co-researcher Dr Paul O'Brien from the University of Leicester, UK.
"By finding the most distant objects we get an estimate, of course, of when the first objects formed," he told BBC News. "But then if you can find a location on the sky - in this case of a single star - you can go and look for the galaxy this object is presumably in, and you can start to study the very first galaxies.
"Because gamma-rays can get right through dust, this gives you a good, unbiased way of finding those first galaxies. One could just find very bright galaxies, whereas Swift means we can find the smaller galaxies, too. It was all of these objects that grew up to form the Universe we see around us today. If you think in terms of a human lifespan, it's about understanding what the Universe was like as a toddler."
The Swift mission was launched in 2004. It is a US space agency-managed venture but has a big UK and Italian contribution.
Britain's major input has been to provide an X-ray camera and core elements of the satellite's Ultraviolet/Optical Telescope.
Observations made at longer wavelengths - as in this infrared image of GRB 090429B taken by the Gemini North Telescope - are used to work out the distance Jonathan.Amos-INTERNET@bbc.co.uk
The couple worked to defend the Amazon rainforest A prominent Brazilian conservationist and his wife have been killed in the Amazon region, police have said.They said Joao Claudio Ribeiro da Silva and Maria do Espirito Santo were ambushed in Para state, near the city of Maraba.
The environmentalist had repeatedly warned of death threats against him by loggers and cattle ranchers.
News of the killings came hours before Brazil's Chamber of Deputies passed a law that eases deforestation rules.
The government has ordered an immediate investigation and promised to catch those responsible for the deaths of Mr Da Silva and his wife.
The bodies of the couple were found inside the nature reserve, Praialta-Piranheira, where they had been working for the past 24 years.
According to family and friends, the pair had been subjected to numerous threats in the past two years for their environmental activism.
They made a living with eco-friendly cultivation of nuts, fruit and rubber.
Environmental amnestyNews of the deaths came just hours before Brazil's Chamber of Deputies voted on changes to the existing Forest Code.
The legislation, first enacted in 1934 and subsequently amended in 1965, sets out how many trees farmers can cut down.
Regulations currently require that 80% of a landholding in the Amazon remain forest, 20% in other areas.
The new bill, which now needs approval from the Senate and President Dilma Rousseff, reduces the amount of land farmers must keep as forest.
Other changes include some amnesties for those who have illegally cleared land in the past.
Proponents of change argued that the law impeded economic development and said that Brazil had to open more land for agriculture.
Opponents described the legislation as a "disaster".
"It heightens the risk of deforestation, water depletion and erosion," Paulo Gustavo Prado from Conservation International-Brazil told Reuters.
Tunnel vision: economic "business as usual" has contributed to recent unrest, the writers argue As the heads of the world's richest nations prepare to meet for the G8 Summit in the French town of Deauville, the issue of generating jobs is emerging as a major test for the global economy.This is especially true for young people.
The kinds of events that have swept through parts of the Middle East and North Africa in recent months stem, in part, from joblessness, and a mood of frustration and a lack of hope among the unemployed and under-employed.
Youth unemployment in many countries of the region hovers around 23-30%, in some cases even higher.
Yet the crisis is not confined to this region or developing countries alone.
In the Eurozone, youth unemployment has jumped from 14% to 20% in the past few years, and in some countries the rates are higher.
Globally, youth account for a quarter of the working age population, but for 40% of the jobless.
Growth is needed to meet this crisis.
But the challenge facing world leaders is how to generate sustainable growth that delivers social outcomes, including employment and greater equity.
Environmental and labour concerns come together in the "green economy", according to the UN And to do this while keeping humanity's growing environmental footprint within planetary boundaries.
The United Nations Environment Programme (Unep) and the International Labour Organization (ILO), in concert with a wide range of partners, has recently provided an analysis of what a "green economy" could deliver.
Entitled Transition to a Green Economy: Pathways to Sustainable Development and Poverty Eradication, it indicates that switching to this kind of low-carbon, resource-efficient economy offers a major opportunity to achieve these multiple aims.
Investing just 2% of global GDP in 10 key sectors can, with the right kinds of enabling public policies, grow the global economy and importantly generate decent "green" jobs.
And this pathway would avoid the shocks, inequities and environmental decline inherent in current economic models.
Energy for changeOne of the G8's priorities is energy.
Continue reading the main storyThe green shoots of a green economy are sprouting across the globe and generating new kinds of employment opportunities”End Quote Our analysis suggests that investing about 1.25% of global GDP each year in energy efficiency and renewable technologies could cut global primary energy demand by 9% in 2020, and close to 40% by 2050.
Savings on capital and fuel costs in power generation under a Green Economy scenario would be on average $760 billion a year between 2010 and 2050.
Employment levels in the energy sector would be one-fifth higher than under a business-as-usual scenario, as renewables account for close to 30% of primary global energy demand by mid-century.
The G8 has also identified the rational use of natural resources via waste management and recycling as ways to achieve green growth.
Evidence from around the world indicates enormous job potential here too.
China, for example, aims to create 20 million jobs in afforestation and forest-based tourism over the coming years.
Green technologies can take societies forward into a era of greater employment Investments in improved energy efficiency in buildings could generate an additional 2-3.5 million green jobs in Europe and the US alone, with the potential much higher in developing countries.
Germany estimates that investments in clean tech, including renewables and recycling, will generate more jobs than exist in the car industry by 2020.
In Brazil, about half a million people are already employed in recycling and waste management.
The industry generates returns of $2bn per year, while avoiding 10 million tonnes of greenhouse gas emissions; a fully recycling economy there would be worth 0.3% of GDP and could provide quality jobs.
Changing timesOur assessments indicate that the green shoots of a green economy are sprouting across the globe and generating new kinds of employment opportunities.
Jobs in some sectors such as fisheries may decline or change as others grow.
Inclusive labour market policies, skills and social dialogue with employers and workers will be crucial.
The G8 summit in Deauville will review implementation within the world's richest economies and several key G20 members in respect to its Global Energy Efficiency Action Initiative.
The International Energy Agency has estimated that a great deal has been achieved in meeting the initiative's 25 recommendations since the G8 summit in Germany in 2006.
Yet there are still tremendous opportunities to go further, with only around 55% of those recommendations having been adopted even in countries that have gone furthest.
Thus, more than 40% of the energy savings possible, and by inference job generation opportunities, remain to be realised, especially in respect to transport.
And the potential remains to cut greenhouse gas emissions by 8bn tonnes of carbon dioxide per year by 2030.
Future perfect?The G8 summit in Deauville comes just over 12 months before the crucial Rio+20 meeting in Brazil, where the world will come together to evolve a more decisive response to the challenge of 21st Century sustainable development.
Jobless recoveries are in no-one's interest, as the events in the Arab world and elsewhere are showing.
It is time to accelerate and to scale up the transitions towards a green economy that are already underway.
They represent a running chance of growing the economy without degrading the planet.
They also represent a way of rediscovering social values and stability for hundreds of millions of citizens seeking decent, high-quality and, if possible, green jobs.
Juan Somavia is director-general of the International Labour Organization. Achim Steiner is a UN under-Secretary-General and executive director of the UN Environment Programme
Bats use sound to hunt The part of the brain used by people who can "see like a bat" has been identified by researchers in Canada.Some blind people have learned to echolocate by making clicking noises and listening to the returning echoes.
A study of two such people, published in PLoS ONE, showed a part of the brain usually associated with sight was activated when listening to echoes.
Action for Blind People said further research could improve the way the technique is taught.
Bats and dolphins bounce sound waves off their surroundings and by listening to the echoes can "see" the world around them.
Continue reading the main story[They] use echolocation in a way that seems uncannily similar to vision”End Quote Dr Lore Thaler University of Western Ontario Some blind humans have also trained themselves to do this, allowing them to explore cities, cycle and play sports. Brain scan
Researchers looked at two patients who use echolocation every day. EB, aged 43, was blinded at age 13 months. LB, 27, had been blind since age 14.
They were recorded echolocating, while microphones were attached to their ears.
The recordings were then played while their brain activity was being recorded in an fMRI machine.
Increased activity in the calcarine cortex was discovered.
Dr Lore Thaler, from University of Western Ontario, said: "This suggests that visual brain areas play an important role for echolocation in blind people."
The study looked at only two people so cannot say for certain what happens in the brains of all people who learn the technique, but the study concludes: "EB and LB use echolocation in a way that seems uncannily similar to vision."
Susie Roberts, rehabilitation officer at Action for Blind People, said: "This research into brain activity and echolocation is very interesting and improves our understanding of how some visually impaired people may be processing information to help them navigate safely.
"Further investigation may help to improve the way the technique is taught to people in the future, potentially improving their mobility and independence."
The samples were collected from the windscreen of a car in Aberdeen Scientists in Aberdeen have released pictures of volcanic glass particles from Iceland which fell in the city.The images show the jagged edges of the particles, which were taken from the windscreen of a clean car parked at the James Hutton Institute.
They were collected on Tuesday - the same day Ryanair boss Michael O'Leary described the ash cloud as "mythical".
Flights were grounded on Tuesday and Wednesday when ash from the Grimsvotn volcano drifted into Scottish airspace.
The largest of the particles is 0.03mm across, with the smallest just 0.002mm wide. The images were taken using a scanning electron microscope.
Scientists at the institute said their composition showed that they did not come from last year's volcanic eruption in Iceland.
But they added they had not yet been compared with samples from the Grimsvotn eruption.
Ruling challengedThe ash cloud resulted in about 500 flights being cancelled across Europe after parts of British airspace were closed.
One of the worst hit countries was Scotland which saw flights at its main airports cancelled and hundreds of passengers stranded.
On Tuesday, Ryanair said it had flown over Scotland and challenged a ruling some flights should be grounded.
It said its 90-minute flight at 41,000ft showed there was "no visible volcanic ash cloud or evidence of ash on the airframe, wings or engines".
However, the CAA said the flight had not entered the so-called red zone.
Recent Met Office forecasts have shown that high density volcanic ash is no longer an immediate threat over the UK.
And Scottish transport minister Keith Brown has said bank holiday travel in Scotland was unlikely to be disrupted.
The James Hutton Institute was formed by bringing together the Macaulay Land Use Research Institute and Scottish Crop Research Centre.
The Welsh Government wants more renewable electricity Wales has to move to a green economy as fast as possible, says First Minister Carwyn Jones.The next 10 years must be "Wales's energy decade", he told a conference.
At the same event, Welsh Secretary Cheryl Gillan said politicians and businesses could not ride roughshod over local people's opinion.
They spoke two days after hundreds of campaigners descended on the Welsh assembly to protest against wind energy plans for mid Wales.
Mr Jones told a renewable energy conference in Cardiff that he had taken personal responsibility for energy policy within the Welsh government.
He said: "We see the next 10 years in Wales as our country's energy decade and we must exploit its full potential. It will be a decade when we press ahead with growth of the renewable and low carbon energy sector."
His administration wants to double the amount of electricity generated from renewable sources by 2025 and to satisfy almost all Wales's energy needs from low-carbon sources by 2050."We've got to shift to a resource-efficient, green economy as fast as possible. That move is vital, both to play our part in the global fight against climate change and also to promote greener, sustainable jobs."
In a nod to this week's protest, the first minister also said it was essential people understood "what is happening and why it is happening".
Around 1,500 people objecting to controversial power and wind energy plans for mid Wales protested on the steps of the Senedd on Tuesday.
'Low-carbon economy'Dozens of pylons, some measuring 154ft (47m), and a substation are earmarked to connect with about 10 wind farms.
The Welsh government has identified seven areas across mid and south Wales as potential sites for wind farms.
In mid Wales, it could mean a line of 50 metre (164ft) pylons carrying 400,000 volt electricity cables from north Powys to near Shrewsbury, Shropshire.
Mrs Gillan said the UK government was determined to transform Britain permanently into a low-carbon economy, but the protest showed how controversial wind farms were.
Onshore wind power has a role to play, she said, but added: "That does not mean that politicians or developers can ride roughshod over local opinion.
"Rather, they should work with communities to ensure that proposals have local support and are sympathetic to the environment around them."
The Welsh government wants decisions over big renewable energy schemes between 50 and 100 megawatts devolved to Cardiff. But Mrs Gillan said the UK government had no plans to change the current systems.
"We need to ensure that the decisions we make are consistent across England and Wales," she said.
The study looked at pockets of volcanic material locked in glass An analysis of sediments brought back by the Apollo 17 mission has shown that the Moon's interior holds far more water than previously thought.The analysis, reported in Science, has looked at pockets of volcanic material locked within tiny glass beads.
It found 100 times more water in the beads than has been measured before, and suggests that the Moon once held a Caribbean Sea-sized volume of water.
The find also casts doubt on aspects of theories of how the Moon first formed.
A series of studies in recent years has only served to increase the amount of water thought to be on the Moon.
The predominant theory holds that much of the water seen on the lunar surface arrived via impacts by icy comets or watery meteorites.
But this recent find is shedding light on how much water is contained in the Moon's interior, which in turn gives hints as to how - and from what - it formed.
In 2008, a team of researchers from the Carnegie Institution and Brown and Case Western Reserve universities analysed the water content found in samples of lunar magma returned by Apollo missions.
They wrote in a Nature paper that the samples contained about 10 times more water than they expected.
The orange soil was discovered during the Apollo 17 mission However, the magma they studied had formed in "fire fountain" volcanic events, much like those seen in locations on Earth such as Hawaii, which would have boiled off much of the water that they contained.
Now the same team has found a number of geological "time capsules" among the beads.
"What we've done now is find samples of magma that are present as 'inclusions' that are trapped inside solid crystals called olivine," explained Erik Hauri, a geochemist from the Carnegie Institution and lead author of the new research.
"Because this magma is trapped inside a crystal, during an eruption it can't lose its water, so these melt inclusions preserve the original water content of the magma," he told BBC News.
The team found that those lockets of lunar magma contained some 100 times as much water as the previous samples - meaning that the lunar interior once held as much water as the layer of the Earth lying just below the crust.
'Not consistent'As with the 2008 study, the find adds even more confusion to theories of how the Moon formed.
Continue reading the main storyI think in its very basic form, the impact theory idea is probably still correct, but there's something fundamental... that we don't understand”End Quote Erik Hauri Carnegie Institution It is widely thought that a Mars-sized object slammed into the Earth just as it was forming, throwing out a disc of fragmented, molten material that eventually coalesced into the Moon.
But in that scenario, the extreme temperatures generated by the impact would have simply boiled off the water, and the moon should have started out relatively dry.
While there is a great deal of evidence to support the theory, both in terms of computer models of planetary formation and of the comparable amounts of various elements found both here and on the Moon, Dr Hauri said something just doesn't add up.
"These things are not consistent with the amount of water that we find," he said.
"I think in its very basic form, the [impact theory] idea is probably still correct, but there's something fundamental about the physics of the process that we don't understand."
The MPCV will take humans beyond the ISS, to destinations such as Mars Nasa has confirmed that the vehicle it will use to send astronauts to places like asteroids will be based on its Orion capsule concept.Orion was the ship being built to return America to the Moon before the project was cancelled last year by President Barack Obama.
The US space agency says the financial investment and the engineering lessons learned should not be wasted.
It wants the new Multi-Purpose Crew Vehicle to benefit from that heritage.
Mr Obama has said he would like humans to visit a space rock in the 2020s. The MPCV would be the ship that takes them there. It would also have a role in any human mission to Mars - the destination Nasa is aiming to reach in perhaps the 2030s.
Orion was conceived as a high-spec vehicle that could visit the ISS and do deep-space destinations Lockheed Martin was the American company leading the development of Orion. It will keep the prime contractor role on the new ship.
"We are committed to human exploration beyond low-Earth orbit and look forward to developing the next generation of systems to take us there," said Nasa Administrator Charles Bolden in a statement.
The MPCV will be capable of carrying four astronauts on 21-day missions. It would start those journeys by launching on the top of an as-yet-undefined big rocket and end them by splashing down in the Pacific off California.
Nasa says the 23-ton spacecraft would have a pressurized volume of 19.5 cubic metres (690 cu ft), just over nine cubic metres (300 cu ft) of which would be habitable.
On missions longer than 21 days, the MPCV would be attached to other modules.
"During these missions to asteroids or Mars, or to the moons of Mars, this vehicle would be just maintained in more dormant mode while the crew would be in another volume which would have longer-term consumables and capability to support them," explained Doug Cooke, associate administrator for the agency's Exploration Systems Mission Directorate in Washington.
"In terms of deep space exploration, we hope to have test flights obviously in this decade. We're not exactly sure when, but certainly as early as possible. Those would be missions beyond low-Earth orbit."
Investment in Orion has already topped $5bn Orion was one of the centrepieces of former President George W Bush's Constellation programme, which sought to return Americans to the Moon using two new rockets and a high-spec capsule.
But the initiative was cancelled by his successor because of its burgeoning cost - $9bn at the time Mr Obama ordered it be shut down. Investment in Orion alone to date is put at slightly more than $5bn.
Many commentators expected elements of Constellation to re-surface in whatever programme replaced it, and some sort of Orion derivative was an obvious prospect.
But Nasa moved swiftly on Tuesday to correct the idea that the adoption of the MPCV was somehow a move on the part of the agency to protect "old ways" of doing business.
Mr Cooke said the Orion government and industry team had shown exceptional creativity in finding ways to push costs down.
However, he could not say what the final development bill would be or how much the recurring costs would be on operational MPCVs.
Nasa will also need at some stage to define a heavy-lift rocket to put in orbit the MPCV and any associated exploration equipment.
The SpaceX company claims its Dragon capsule will also be a highly capable vehicle The US Congress, through the Nasa Authorisation Act 2010, has mandated that this rocket should be launching by the end of 2016, although the agency has previously stated that it views this timeline as challenging. It promises more details on the launcher "in the coming weeks".
Nasa's current fleet of space vehicles - the shuttles - are being retired, with the Atlantis orbiter set to end their operation for good with a final flight in July.
America will then rely on Russian Soyuz vehicles to get its astronauts to the International Space Station (ISS) until a new wave of US commercial carriers enter service around the middle of the decade.
In the main, these crew carriers will be substantially cheaper to build and operate than the MPCV, and will not be capable of venturing beyond low-Earth orbit where the ISS resides.
However, the SpaceX company claims the Dragon capsule it is developing for journeys to the ISS will eventually be able to match any task given to the Lockheed Martin ship, and do it at a greatly reduced price.
Jonathan.Amos-INTERNET@bbc.co.uk
Victoria Hill spent six weeks on the ice, carrying out research in temperatures as low as -40C A scientist hopes that a better understanding of what is happening beneath the Arctic ice will offer an insight into why summer sea ice is melting at rate that is alarming experts.Victoria Hill, an oceanographer from Old Dominion University, US, was one of five scientists who spent six weeks in the barren, frozen landscape where temperatures fall to -40C (-40F).
"As a scientist, the reason I am prepared to come out here and be cold is because of the desire to learn and answer burning questions I have about what is going on up here, why the ice is melting as fast as it is," she told the Earth Reporters programme.
Arctic summers are projected to be free of sea ice by the middle of the century, with some studies warning that it could occur in the next decade.
Professor Hill explained that the Arctic played a key role in regulating the Earth's climate.
"The Arctic drives global circulation and therefore our global climate."
Ocean currents transport vast volumes of water around the planet. They are known as "thermohaline" circulations because they are affected by variations in salinity and temperature.
As warm water evaporates, the salinity increases and temperature falls resulting in a mass of denser water, which sinks and drives the current.
"If the Arctic gets a lot warmer, we will see a slowing down of the current," she said.
"If that happens, we'll see the climate in places like England change subtly, getting colder because the warmer waters from the south won't be pushed north."
Heart of the matter
Professor Hill said her work focused on how the Sun's energy is absorbed, accelerating the ice melt.
A team of five scientists set up camp 1,000 miles north of the Arctic Circle "In early Spring, small particles of organic matter are seen in Arctic waters, and also found in sea ice - I called it 'ocean tea' and I think it may be formed from algae," she suggested.
"My theory is that this organic matter absorbs the Sun's energy, making the ice melt faster."
In order to test her idea, Professor Hill collects samples of water from depths of up to 500m beneath the ice, as well as ice core samples.
When examining the samples, she finds "a lot of algal material".
"This is really exciting," she explains. "What that means is that as ice melts from the bottom, that material will come into surface water, absorbing light and heating up the water."
She added that the next question was to identify the source of the organic matter.
"Is it coming from ice algae, phytoplankton, rivers? How much of it is there and how is it affecting heating?
"They are small questions; but when you link tall these questions together, we end up with an answer to why sea ice is melting so fast."
Role reversal: insects prey upon reptiles A giant water bug has been photographed eating a juvenile turtle in an unusual predatory role reversal.Large bugs in the Lethocerinae family have been known to prey upon small vertebrates including fish and frogs.
But unlike insects that often fall prey to reptiles, scientists have observed one particular species of bug eating snakes and a turtle.
Dr Shin-ya Ohba recorded the unusual behaviour during night sampling in western Hyogo, central Japan.
Writing in the journal Entomological Science, Dr Ohba describes observing a Kirkaldyia deyrolli eating a Reeve's pond turtle in a ditch next to a rice field.
Continue reading the main story
These bugs are also known as "giant fish killers" for their carnivorous tastes
Their attraction to artificial lights at night has also earned them the title "electric-light bugs"
Americans also refer to them as "toe-biters" because they have been known to bite unsuspecting swimmers
Using its front legs the giant water bug gripped the turtle, inserting its syringe-like rostrum into the prey's neck in order to feed.The giant water bugs are known to only attack moving prey, so it is likely that the 58mm insect captured and killed the young turtle before feeding on it.
Dr Ohba has also photographed giant water bugs eating snakes in the past.
"Everyone thinks that Lethocerinae bugs live on fishes and frogs. Although eating a turtle and snake are rare in the natural condition, [this evidence] surprises naturalists [by showing] voracious feeding habits," said Dr Ohba.
He suggests that these observations of bugs predating reptiles call into question previously held opinions about predator-prey dynamics in freshwater habitats.
K. deyrolli are native to Japan where they have been found living in rice fields, feeding primarily on small fish and frogs.
The species is listed as endangered by the Japanese Environment Agency following serious declines over the last forty years, reportedly due to habitat loss and water pollution.
A giant water bug successfully takes on a snake Giant water bugs are the largest of the true bugs (Hemiptera) and members of the sub-family Lethocerinae are found in freshwater ponds, lakes and slow-moving streams and rivers across North America, South America and East Asia.
Lethocerus species can grow up to 15cm long, are nocturnal and can fly, relying on the light of the full moon to migrate.
They possess a venomous bite which they use to subdue prey and are occasionally known to bite humans, resulting in a burning pain that can last several hours.
Members of Source London who have paid the ?100 annual fee are now able to use any of the points.
Earlier this year, mayor Boris Johnson announced plans to install 1,300 charging points by 2013, scaling back from the 7,500 he promised a year earlier.
But the Green Party said the mayor's electric car ambitions had "gone flat".
Source London is a network of charging points across London which can be accessed by plug-in electric car users who have registered.
'Air quality benefits'Green Party London Assembly member Darren Johnson said: "The mayor never explained how he would fund the ambitious plans for 25,000 charging points which he launched with a big fanfare in 2009.
"He has also failed to guarantee that the charging points will run on renewable energy, so the environmental gains are far less than they should be."
Kulveer Ranger, from the mayor's office, said: "The mayor has been leading the national charge on electric vehicles having championed them in London for the past three years since his election.
"There are obvious and immediate air quality benefits to the increased use of electric vehicles, helping us to deliver an improved quality of life for Londoners."
There are currently 2,100 plug-in electric cars registered as exempt from the congestion charge, according to the mayor's office.
The layers representing the build-up of hailstones can be seen in cross-section A study of hailstones has found large numbers of bacteria at their cores.The find lends credence to the "bio-precipitation" idea, which suggests that bacteria are actively involved in stimulating precipitation.
The bacteria have protein coatings that cause water to freeze at relatively warm temperatures.
Researchers at the American Society for Microbiology meeting suggest bacteria may have evolved to use the water cycle to facilitate their own dispersal.
The micro-organisms that can be found in precipitation such as snow have been studied since the 1960s.
One bacterium that has appeared in many contexts is Pseudomonas syringae, which expresses a protein on its surface that encourages an orderly arrangement of water molecules.
That in turn acts as a "nucleation" site, stimulating the formation of ice at temperatures far higher than those normally required.
So effective is P. syringae at the task that it is used in a commercially-available mixture for snow machines.
In nature, the ice that P. syringae stimulates can damage the walls of plant cells, allowing the bacterium to feed on the cells' interiors.
Only in recent years, however, has a wider role for the bacterium's strategy started to become more clear.
In 2008, Brent Christner of Louisiana State University reported finding significant numbers of bacteria in snow found around the world.
'Intriguing'Now, Alexander Michaud of Montana State University has added to the idea, having collected hailstones on the university campus following a major hailstorm in 2010.
P syringae bacteria are well-known "catalysts" for ice formation He analysed the hailstones' multi-layer structure, finding that while their outer layers had relatively few bacteria, the cores contained high concentrations.
"You have a high concentration of 'culturable' bacteria in the centres, on the order of thousands per millilitre of meltwater," he told the meeting.
The bacteria are known to gather together in "biofilms" on the plant surfaces and can form bacteria-rich aerosols in forest canopies - aerosols that can rise on updraughts, eventually stimulating precipitation in clouds at temperatures far higher than would be required if soot or dust served as the nucleation sites.
Dr Christner, also present at the meeting, said the result was another in favour of the bio-precipitation idea - that the bacteria's rise into clouds, stimulation of precipitation, and return to ground level may have evolved as a dispersal mechanism.
"It's an interesting idea that's been thrown around for decades but only recently has the data accumulated to support it," he told the meeting.
"As a microbiologist, this idea that... an organism could piggy-back on the water cycle I find just intriguing.
"We know that biology influences climate in some way, but directly in such a way as this is not only fascinating but also very important."
Researchers have shown differences in autistic brains The brains of people with autism are chemically different from those without autism, according to researchers. A study, published in the journal Nature, showed the unique characters of the frontal and temporal lobes had disappeared.
Different genes should be active in each region, but autistic brains had the same pattern of gene expression.
The National Autistic Society said the results could be important for future treatments.
Autism spectrum disorders, including Asperger's syndrome, are common and affect more than 500,000 people in the UK.
They are thought to be caused by a combination of genetics and the environment.
Professor Daniel Geschwind, from the University of California, Los Angeles, said: "If you randomly pick 20 people with autism, the cause of each person's disease will be unique.
"Yet when we examined how genes and proteins interact in autistic people's brains, we saw well-defined shared patterns. This common thread could hold the key to pinpointing the disorder's origins."
DifferencesThe scientists in the UK, US and Canada compared samples from 19 autistic brains and 17 without.
They noticed that 209 genes linked to the way brain cells work and talk to each other were working at a lower level in autistic brains while 235 genes linked to immune and inflammatory responses were expressed more strongly.
The researchers said many of these genes had already been linked to the condition.
They also noted that there was no longer a difference in the genes expressed in the frontal and temporal lobes in the brain.
Professor Daniel Geschwind said: "Instead, the frontal lobe closely resembles the temporal lobe."
It is likely due to defective brain development, they argue.
Richard Mills, director of research at the National Autistic Society said: "We are beginning to better understand the differences between the brains of people with autism and those without.
"If replicated these findings are important for the development of interventions which may reduce the more disabling effects of autism.
"They also confirm the importance of research that can shed light on underlying mechanisms. It is critical that we continue our investment in high quality research consortia."
The decision for Kings Cliffe near Peterborough follows a two-year stand-off between the hazardous waste company Augean and campaigners.
Some 98% of people who voted in local referendums opposed the plans.
This was seen as a test case for waste companies and for the government's proclaimed localism commitment.
Communities Secretary Eric Pickles said he had accepted expert advice that planning permission for this additional waste "would not be harmful to the local community".
Test caseKings Cliffe Waste Watchers, who have been campaigning against the plan, reacted to the decision by saying it was disappointed that the wishes of local residents had been ignored by a minister who had "declared his commitment to local decision making".
BBC local government correspondent Mike Sergeant says the Kings Cliffe saga has been seen as a test of the government's commitment to localism - ie allowing local communities to make decisions rather than ministers and officials in Whitehall.
A Department for Communities and Local Government spokesman said Mr Pickles had taken account of the detailed findings of the planning inspector who had held a public local inquiry which was open and transparent to the public.
Continue reading the main story[Mr Pickles] has hardly demonstrated the level of commitment expected from one who is trying to steer a localism bill through Parliament”End Quote Kings Cliffe Waste Watchers Northamptonshire county councillors had unanimously rejected the plan in March 2010.
Augean says the waste, which is mainly soil and rubble from old nuclear power stations, is very low-level radioactive. It says the amount of radiation emitted will be a small percentage of what we are exposed to naturally every day.
The Kings Cliffe Waste Watchers protest group said the decision was not just of local importance as it was a test case for the government, meaning it could be repeated across the country.
It believes the site will be taking construction rubble from decommissioned nuclear plants because the existing national low-level radioactive waste repository near the Sellafield nuclear plant at Drigg in Cumbria is filling up.
They say the Kings Cliffe landfill would be the first of its kind to take radioactive material from the nuclear industry, nowhere near any nuclear plant.
The residents of Kings Cliffe say an underground water source runs from below the landfill site and that a number of springs, pools and streams in the village could be contaminated.
They say their area, which is more than 90 miles from the nearest nuclear power station, has been unfairly singled out for the waste.
Our correspondent says the prospect of a new generation of nuclear power stations raises some difficult problems for the UK.
Old reactorsAs old reactors are taken out of service, the demolition of surrounding buildings will produce a large amount of low-level radioactive waste.
It is not always possible to dispose of this on the site of the old power station or at existing hazardous waste facilities.
Kings Cliffe Waste Watchers said: "In overturning the decision of the county council, and the wishes of all local government organs, he [Mr Pickles] has hardly demonstrated the level of commitment expected from one who is trying to steer a localism bill through Parliament.
"We are also surprised that the government should consider the forcible disposal of nuclear waste in an area so evidently unprepared for it a positive approach to dealing with the decommissioning of nuclear facilities."
A DCLG spokesman said: "This is an existing landfill site which handles hazardous waste. Having considered all the evidence and representations, the minister has accepted the expert planning advice that granting a temporary planning permission for additional waste would not be harmful to the local community."
Corby MP Louise Bagshawe said: "This government has professed commitment to localism, we had a local referendum at the ballot box, not a petition, actual votes cast and 96% of people were against this dump.
"I will be asking the Secretary of State why his department has taken this appalling decision.
"This seems like a predetermined decision and I am deeply unhappy."
Dr Gene Wilson, from Augean, said: "We hope members of the local community, who have had reservations about these proposals, can be reassured that both the Secretary of State and the Environment Agency would not authorise permission for disposal of these wastes unless they were completely satisfied they present negligible risk to human health or the environment."
The Mundurucu do not even have words for geometric concepts Tests given to an Amazonian tribe called the Mundurucu suggest that our intuitions about geometry are innate.Researchers examined how the Mundurucu think about lines, points and angles, comparing the results with equivalent tests on French and US schoolchildren.
The Mundurucu showed comparable understanding, and even outperformed the students on tasks that asked about forms on spherical surfaces.
The study is published in Proceedings of the National Academy of Sciences.
The basic tenets of geometry as most people know them were laid out first by the Greek mathematician Euclid about 2,300 years ago.
This "Euclidean geometry" includes familiar propositions such as the fact that a line can connect two points, that the angles of a triangle always add up to the same total, or that two parallel lines never cross.
The ideas are profoundly ingrained in formal education, but what remains a matter of debate is whether the capacity, or intuition, for geometry is present in all peoples regardless of their language or level of education.
To that end, Pierre Pica of the National Centre for Scientific Research in France and his colleagues studied an Amazon tribe known as the Mundurucu to investigate their intuitions about geometry.
"Mundurucu is a language with only approximative numbers," Dr Pica told BBC News.
"You don't have a lot of geometrical terms like square or triangle or anything like that, and no way of saying two lines are parallel... it looks like the language does not have this concept."
Dr Pica and his colleagues engaged 22 adults and eight children among the Mundurucu in a series of dialogues, presenting situations that built up to questions on geometry. Rather than abstract points on a plane, the team suggested two villages on a notional map, for instance.
'Playing tricks'Similar questions were posed to 30 adults and children in France and the US, some as young as five years old.
The Mundurucu people's responses to the questions were roughly as accurate as those of the French and US respondents; they seemed to have an intuition about lines and geometric shapes without formal education or even the relevant words.
The questions posed to the tribe echo a classic Socratic dialogue on geometry "The question is to what extent knowledge - in this case, of geometry - is dependent on language," Dr Pica explained.
"There doesn't seem to be a causal relation: you have a knowledge of geometry and it's not because it's expressed in the language."
Most surprisingly, the Mundurucu actually outperformed their western counterparts when the tests were moved from a flat surface to that of a sphere (the Mundurucu were presented with a calabash to demonstrate).
For example, on a sphere, seemingly parallel lines can in fact cross - a proposition which the Mundurucu guessed far more reliably than the French or US respondents.
This "non-Euclidean" example, where the formal rules of geometry as most people learn them do not hold true, seems to suggest that our geometry education may actually mislead us, Dr Pica said.
"The education of Euclidean geometry is so strong that we take for granted it's going to apply everywhere, including spherical surfaces. Our education plays a trick with us, leading us to believe things which are not correct."
One type of observation measured a pattern in the distribution of galaxies First results from a major astronomical survey using a cutting-edge technique appear to have confirmed the existence of mysterious dark energy.Dark energy makes up some 74% of the Universe and its existence would explain why the Universe appears to be expanding at an accelerating rate.
The finding was based on studies of more than 200,000 galaxies.
Scientists used two separate kinds of observation to provide an independent check on previous dark energy results.
Two papers by an international team of researchers have been accepted for publication in the Monthly Notices of the Royal Astronomical Society journal.
One type of observation used by the astronomers involves measuring a pattern in how galaxies are distributed in space. This pattern is known by the term "baryon acoustic oscillations".
The second type of observation involves measuring how quickly clusters of galaxies have formed over time. Both of these techniques confirmed the existence of dark energy and the acceleration in the expansion of the Universe.
The concept of dark energy was first invoked in the late 1990s by studying the brightness of distant supernovas - exploding stars.
Einstein was rightTo explain why the expansion of the Universe was speeding up, astronomers had to either rewrite Albert Einstein's theory of gravity or accept that the cosmos was filled with a novel type of energy.
"The action of dark energy is as if you threw a ball up in the air, and it kept speeding upward into the sky faster and faster," said co-author Dr Chris Blake of the Swinburne University of Technology in Melbourne, Australia.
"The results tell us that dark energy is a cosmological constant, as Einstein proposed. If gravity were the culprit, then we wouldn't be seeing these constant effects of dark energy throughout time."
The Anglo-Australian telescope was used in the galaxy survey The latest findings have come from a galaxy survey project called WiggleZ, which began in 2006 and finished this year. WiggleZ used data from Nasa's Galaxy Evolution Explorer (Galex) space telescope and the Anglo-Australian Telescope on Siding Spring Mountain in Australia.
The survey mapped the distribution of galaxies in an unprecedented volume of the Universe, looking eight billion years back in time - more than half the age of the Universe.
Cosmologist Bob Nicholl, who was not involved with the research, told BBC News: "This is a major step forward. These guys are serious, major scientists and we've been waiting for this result for some time.
The professor of astrophysics at Portsmouth University, UK, added: "It's re-confirmation of dark energy, it gives us another data point to fit our theories around and it shows us the way to the future. More astronomers are going to be doing this in years to come."
While dark energy makes up about 74% of the Universe, dark matter - which does not reflect or emit detectable light - accounts for 22%. Ordinary matter - gas, stars, planets and galaxies - makes up just 4% of the cosmos.
However, despite scientists being able to infer the existence of dark energy and dark matter, these phenomena still elude a full explanation.
Paul.Rincon-INTERNET@bbc.co.uk
Dozens of swans have been slaughtered around the UK this year, a serial cat killer is on the loose in Norfolk, and over the past three decades hundreds of horses have been mutilated. But how is serial animal violence investigated, asks Tom de Castella.Most people have seen enough television shows and read enough newspaper reports to know what happens when a murder investigation starts.
The crime scene is sealed off, forensic officers move in looking for fingerprints and DNA evidence, detectives go door- to-door. But what's the procedure for investigators when the victim of a killing is an animal?
Every month gruesome cases come to light. Swans are regularly in the firing line. At least 40 of the birds were killed by humans in Somerset during the first three months of the year.
Killers John Duffy and David Mulcahy are believed to have tortured animals In the last 10 days four men have been arrested over the shooting of eight swans near Stoke-on-Trent. And last week a man was convicted at Harrogate Magistrates' Court for killing a swan with a shotgun.
Meanwhile the number of cats killed around one street in the Norfolk village of Harleston has risen to at least 10 in the past four years. And since the 1980s there have been hundreds, possibly thousands, of horses slashed, mutilated and sexually assaulted across Britain. In Essex this month a Shetland pony was sexually assaulted and then hacked to death. So how do the RSPCA investigate such violent sprees?
Without witnesses, killings are difficult to crack, says Andy Shipp, a senior prosecution case manager at the charity. "It's pretty rare to just have a dead animal. Unless you've got something else to go on, you're up against it."
Inspectors often employ common police procedures. At the crime scene they take photographs of the dead or injured animal and collect forensic evidence for fingerprinting and DNA testing.
Shipp recalls a case in Staffordshire where a cow was found alive with a crossbow bolt through its head. The local inspector tracked down the killer by collecting DNA evidence from a discarded bolt in the field. The DNA matched up to a young man on the DNA register and he was successfully prosecuted.
Continue reading the main storyDr Gary Macpherson, consultant forensic clinical psychologist
Animal cruelty is widely known in psychology as a "red flag" indicator of psychopathy and future aggressive behaviour. Animal crime involves a callous disregard for living creatures and a lack of empathy which may translate into the way an offender views human beings.
There is a wealth of evidence to show that psychopathic individuals in particular have a history of cruelty and sadistic acts to animals. I have encountered offenders with a history of cruelty to animals.
There's no hard and fast rule about degrees of cruelty. I presume that the closer the animal is to the human hierarchy the worse it is.
There are multiple reasons why a person chooses to engage in animal cruelty - psychological reasons or reasons related to mental illness or 'hearing voices'.
In a few cases it's sheer sadistic badness.
A post-mortem examination is carried out by an animal pathologist to establish cause of death, although it may not ascertain precise details, such as which poison has been used.Collars and microchips can lead investigators to the owner. CCTV footage is another tool that can capture crucial evidence, such as when a woman in Coventry dumped a cat into a wheelie bin.
Inspectors looking for witnesses carry out door-to-door inquiries and if all else fails the RSPCA will make an appeal via the local press.
In extreme cases - such as the killing of swans in Somerset - the RSPCA works closely with police. There have been no convictions for the killings but a man has been charged with the unlawful possession of a shotgun.
The RSPCA can also bring in its own Special Operations Unit, a plain clothes team with expertise in surveillance and forensics used to tackle dog fighting and badger digging.
According to Barry Fryer, chief superintendent of the unit, forensics is becoming increasingly important. "If a man has got badger blood on his jeans we can compare it with an animal at the crime scene. Our database will show the odds of those two samples being the same and link it to the criminals."
Fingerprinting is one avenue for evidence gathering Soil on boots can also be traced to a specific area as can pollen - the latter a technique used in the Soham murder trial to link Ian Huntley to the ditch where his victims were dumped.
But most investigations are hardly hi-tech, says Simon Evans, an RSPCA inspector in the Rhondda Valley. Unlike the TV show CSI, there are no white protective suits - RSPCA inspectors wear nothing more exotic than gloves. Neither do they carry out psychological profiling of suspects.
"You rely on that person making a mistake and being seen or leaving DNA at the scene," he says. "When people come forward with information it's like a ray of light."
An RSPCA inspector is already hunting the Norfolk cat killer.
When animals are poisoned - as with most of the cats in Harleston - the key is to track down the "bait station", Evans says. In a similar case, he came across a piece of chicken floating in a poison made from a common household product. His task was then to prove that the chicken was put in intentionally as bait.
Continue reading the main story May: Two adults and 6 cygnets were shot dead at a Stoke-on-Trent nature reserveMan convicted at Harrogate Magistrates' Court for killing a swanA Shetland pony sexually assaulted and hacked to death in Essex. Four people arrestedApril: Tenth cat killed in four years in Norfolk village of Harleston, two others missing presumed deadMarch: Death toll of swans killed in Somerset reaches 40February: Eight swans shot dead in Somerset2010: The Daily Mail reports that 33 cats have been killed in a three year period in Stogursey and Bridgwater in Somerset2009: Golden eagle found dead in the Cairngorms after being poisoned. At least 32 birds of prey shot dead during the year and 81 poisoned.In 12 years he estimates he's brought about the convictions of a dozen people. Most crimes are unsolved.He remembers the case of a greyhound found close to death on a mountainside, having been shot in the head with a stun gun. Evans managed to track the dog down to an unlicensed racetrack in the area, where staff put him in touch with the greyhound's owner.
It turned out that the dog had broken its leg and the owner had given someone ?10 to shoot it. The hired killer claimed to have shot it dead but had only stunned it and dumped it with a hole in its head on the mountain. The man was tried, convicted and imprisoned.
But six months in prison is the maximum sentence for animal cruelty, which some animal lovers feel is insufficient. Sir Terry Pratchett, who has offered a ?10,000 reward for catching whoever is behind the Somerset swan killings, believes the law is too lenient for serious animal cruelty.
"People who do this sort of thing to an animal are probably a danger to people as well. I don't think the punishment will fit the crime," he said.
For Evans the outcome of the greyhound case was a "triumph", which makes the painstaking work worthwhile. "These people aren't normal - the anger and malice they exhibit can be disturbing. When you go to court and the person gets sent to prison it's fantastic."
The motive for animal killings is often not clear, but one category of deaths is often attributed to disgruntled farmers and gamekeepers. The RSPB's most up-to-date figures reveal that in 2009 32 birds of prey were shot and 81 poisoned.
Whatever species is involved, the tenacity of investigators pursuing culprits despite a lack of evidence remains the same.
