Pi calculated to 'record number' of digits

Pi is an irrational number, meaning its digits go on forever

A computer scientist claims to have computed the mathematical constant pi to nearly 2.7 trillion digits, some 123 billion more than the previous record.

Fabrice Bellard used a desktop computer to perform the calculation, taking a total of 131 days to complete and check the result.

This version of pi takes over a terabyte of hard disk space to store.

Previous records were established using supercomputers, but Mr Bellard claims his method is 20 times more efficient.

The prior record of about 2.6 trillion digits, set in August 2009 by Daisuke Takahashi at the University of Tsukuba in Japan, took just 29 hours.

However, that work employed a supercomputer 2,000 times faster and thousands of times more expensive than the desktop Mr Bellard employed.

Precision targeted

These herculean computations form part of a branch of mathematics known as arbitrary-precision arithmetic - simply put, knowing a given number to any amount of decimal places.

It is hard to overstate just how long the currently determined pi is; reciting one number a second would take more than 49,000 years.

But it is not simply the number that interests Mr Bellard.

"I am not especially interested in the digits of pi," he said.

"Arbitrary-precision arithmetic with huge numbers has little practical use, but some of the involved algorithms are interesting to do other things."

Mr Bellard plans to release a version of the program he used to do the calculation, but says that carrying on with any further billions of digits "will depend on my motivation".

Ivars Peterson, director of publications at the Mathematical Association of America, said that the result is just the latest in a long quest for a longer pi.

"Newton himself worked on the digits of pi and spent a lot of time using one of the formulas he developed to get a few extra digits," Mr Peterson told BBC News.

In modern times, pi has served as more than just a simple but lengthy constant, however.

"People have used it as a vehicle for testing algorithms and for testing computers; pi has a precise sequence of digits, it's exactly that, and if your computer isn't operating flawlessly some of those digits will be wrong," he explained.

"It's more than just for the fun of it - pi is a way of testing a method and then the method can be used for other purposes."

Child brain tumours 'treatable'

Aggressive childhood brain tumours could be treatable with a novel combination of two existing cancer drugs, a study suggests.

Researchers led by the Institute of Cancer Research (ICR) examined 90 tumours from children and found two new genetic abnormalities in nine of them.

They were then able to kill these abnormal tumours, in laboratory tests, by combining the two existing drugs.

But one expert says the findings remain "far off being applicable to patients".

In the UK, about 400 children are diagnosed with brain tumours every year.

The research, published in the journal Clinical Cancer Research, brought together scientists from the UK, France, Portugal, Brazil and America.

The abnormal tumours - known as glioblastomas, aggressive and often fatal cancers of the brain's glial cells - contained too many copies of the EGFR gene and mutations of the gene the scientists say have never before been found in children.

"Cancers may look the same, but it is only when you get down to the genetic level that you can truly understand them and devise treatments"

Dr Chris Jones

They tried to block the EGFR gene with a drug, erlotinib (Tarceva), used in clinical trials to treat adult glioblastomas, but identified a molecule specific to the children's cells - platelet-derived growth factor receptor (PGFR) - that was making it ineffective.

But when they combined erlotinib with a drug, imatinib (Glivec), they hoped would block the PGFR molecules, they killed a significant number of the cancer cells.

Dr Chris Jones, who led the research, said it proved "that cancers may look the same, but it is only when you get down to the genetic level that you can truly understand them and devise treatments".

Professor Geoff Pilkington, of the Brainstrust charity, said the research, though fascinating, was at too early a stage to turn into a treatment for patients.

"This sort of twin therapy is a good thing to consider for the future," he said.

Bur he added: "The cells of the brain seem to be unusually resistant to anything thrown at them."

Bloodhound diary: Numbers crunching

RAF fighter pilot Andy Green intends to get behind the wheel of a car that is capable of reaching 1,000mph (1,610km/h). Powered by a rocket bolted to a Eurofighter-Typhoon jet engine, the Bloodhound car will mount an assault on the land speed record.

Wing Cmdr Green is writing a diary for the BBC News Website about his experiences working on the Bloodhound project and the team's efforts to inspire national interest in science and engineering.

AVOIDING THE BIG ROLL

I've just seen the latest figures for participation in the Bloodhound education programme - over 3,300 schools, over 200 Further Education colleges and 35 universities.

Air pressure at Mach 1.3 on different shapes of rear suspension fairing

That's over 10% of all the schools in the UK, which is just incredible.

Perhaps the rest of the project team ought to feel under pressure from the education team - they seem to be outstripping our fund-raising and engineering efforts by a huge margin.

Still, our main aim is to create interest in science and engineering, so this is the way that it should be - the education team is out in front and the rest of us are under pressure to keep up!

The design office is certainly doing its best to keep up, with the "aerodynamic optimisation" (or "getting the back end exactly right") programme tearing along.

The team ran 56 parametric models in four weeks, using the huge computing power available through our IT partner Intel.

Rumour has it that the Met Office is now feeling under pressure, as we're using more computing power than they are... and, in terms of aerodynamics, we're forecasting sunshine!

A great effort from Mark Chapman, Bjorn Rodde and Ben Evans, who gave the rest of us the perfect Christmas present with these results.

While the aerodynamics will keep the car on the ground, it also needs to be dynamically safe as a car. This includes putting the rear wheels wide enough apart to make sure that the car cannot roll over. But how wide is that?

Anyone want to put their name on the tail fin of Bloodhound SSC?

Looking back at the Thrust SSC data, we saw a peak sideways 'G' force of almost 1G - yikes! That is huge (about the same as the maximum cornering force that the average road car will produce). If we put Bloodhound SSC's rear wheels far enough apart to resist that, then the drag will prevent the car from reaching 1,000mph.

Fortunately, Ron Ayers, our performance expert (and one of the cleverest people I know) has pointed out that Thrust SSC's wheels would not have generated 1G side loads by themselves - there just isn't that much grip on the desert.

Instead, it appears that the car developed a couple of degrees of yaw and this created a large aerodynamic side force, which pushed the car sideways but did not risk rolling it over.

We can leave the rear wheels where they are, without any danger of Bloodhound SSC rolling over. Suddenly, I feel much happier. Thanks, Ron.

We've just had some really exciting news of a plan to include recycled materials in the car, which will reduce the carbon footprint for the car's build. This will also give us a great way to include recycling technology in our education programme. We're just working out the details now - more to follow shortly.

Finally, the chance to put your name on the fin of Bloodhound SSC is proving hugely popular.

The Union Flag on the fin will be made up of thousands of tiny coloured names, which is a great way for us to get children (of all ages!) more involved in this astonishing piece of engineering.

Let's hope that the "aerodynamic optimisation" doesn't make the fin too much smaller...

2009 was an amazing year and I can't wait to see what's going to happen during 2010.

The giant Amazon arapaima fish is 'under threat'

A harvested fish is a huge catch

The arapaima, a giant species of fish that lurks in the Amazon river, may be threatened by overfishing.

Studies reveal that errors in the classification of the species could mean that it is being pushed closer to the edge of extinction than thought.

The arapaima is the largest freshwater fish with scales in the world.

But there may actually be four species rather than one, say scientists, and a lack of research and management may allow some to be fished to extinction.

The threat to the future of these fish has been revealed in research conducted by Dr Leandro Castello of the Woods Hole Research Center in Falmouth, Massachusetts, US, and Professor Donald Stewart of the State University of New York in Syracuse, US.

They have reviewed what is known about populations of the arapaima, and conducted detailed investigations into the status of the fish in the wild.

Previously, it was thought there was one species of arapaima (Arapaima gigas), which also goes by the common names pirarucu or paiche.

This perspective is based on a taxonomic review done over 160 years ago.

Adults grow to almost 3m in length and can weigh more than 200kg, making the fish the largest with scales living in freshwater anywhere in the world.

They are also air-breathers, coming to the surface every 5 to 15 minutes to gulp air, a behaviour which allows them to colonise muddy oxygen-poor rivers and lakes within the Amazonian basin and prey on other fish that find it difficult to move in such conditions.

However, in an ongoing study, Prof Stewart has analysed nearly all preserved specimens of supposed arapaima available in museums in the world.

So far he has only found one specimen of Arapaima gigas.

The others are suspected to be closely related species, including some as yet unreported.

"Our new analyses indicate that there are at least four species of arapaima," says Dr Castello.

"So, until further field surveys of appropriate areas are completed, we will not know if Arapaima gigas is extinct or still swimming about."

Concern about the fish's numbers comes from other work done by Dr Castello and Prof Stewart.

For a split second, an arapaima surfaces to gulp air

That suggests that arapaima sexually mature relatively late, and need very specific habitats to both live and reproduce.

Their research also shows that populations of the fish are being put under severe pressure by fishermen.

Because of the fish's huge size and habit of coming to the surface, it has long been a favoured fish to catch, with fisherman using harpoons and gill nets to land their prey.

"They have the curse of being tasty and of having to breathe air," says Dr Castello.

Fishermen have been catching large numbers of arapaima in this way since the 1800s.

But now, while a few populations are increasing, others are being overfished, say the researchers, who have published a paper warning of the fish's fate in the Journal of Applied Ichthyology.

And while Brazil implemented regulations to manage arapaima fisheries some 20 years ago, most fishermen do not follow the regulations, say the authors.

Fishermen capture a young arapaima for ecological studies

"Arapaima can be viewed as badly overexploited and under some level of threat of extinction," says Dr Castello.

One solution, they say, is to encourage community-based schemes for fisheries, and there is much need for additional action on the part of the government.

For example, their research shows that fishermen who specialise in hunting arapaima with harpoons can accurately count the fish, due to the fish's habit of breaching the surface for air.

The fishermen can then select a sustainable proportion of the population to hunt.

"Populations of arapaima managed with this system increased about 50% annually, while yielding increasing catches and hence economic profits to the fishermen," says Dr Castello.

Around 100 such community schemes are in place, and some previously overexploited populations have recovered.

"Such results are extremely rare in wildlife conservation, especially in tropical countries where wildlife conservation challenges are greater than elsewhere," says Dr Castello.

But much more needs to be done to research these fish in more detail and prevent overfishing, the scientists warn.

In particular, "the present situation may be one in which one species of arapaima is recovering in certain areas, while unrecognised species are going extinct," they say.

Biological cells reveal brain chemistry secrets

The cells change colour to reveal specific kinds of neural messages

Scientists have developed biological cells that can give insight into the chemistry of the brain.

The cells, which change colour when exposed to specific chemicals, have been used to show how a class of schizophrenia drug works.

The researchers hope they will also help shed light on how many other drugs work on the brain.

The study, by the University of California - San Diego, is published in Nature Neuroscience. 

Schizophrenia is most commonly associated with symptoms such as delusions and hallucinations.

But people with the illness also struggle to sustain attention or recall information.

A class of drugs called atypical neuroleptics has become commonly prescribed, in part because they seem to improve these problems.

However, the way they altered brain chemistry was uncertain.

It was known that the drugs trigger the release of a large amount of a chemical called acetylcholine, which enables brain cells to communicate with each other.

However, the drugs have also been shown to hobble a receptor on the surface of the receiving cell, which would effectively block the message.

The San Diego team designed biological cells - called CNiFERs - which changed colour when acetylcholine latched onto this particular class of receptors - an event scientists have not previously been able to detect in a living brain.

They implanted the cells into rat brains, then stimulated a deeper part of the brain in a way known to release acetylcholine nearby.

In response, CNiFERs changed colour - proving that they were working.

They then gave the rats one of two atypical neuroleptics. In both cases the drug severely depressed the response from the CNiFERs.

This suggested that the drugs' receptor-blocking action over-rides the increase they trigger in acetylcholine.

Researcher Professor David Kleinfeld said the new cells had great potential to reveal the mysteries of chemical action in the brain.

He said: "It's a world of signalling between cells that we were blind to before."

The researchers say they are already working to redesign CNiFERS so they can detect the activity of other types of receptors as well.

Paul Corry, of the mental health charity Rethink, said: "This study shows the value of mental health research.

"It is eliciting new information that could lead to the development of more effective drug treatments for schizophrenia, which have fewer of the debilitating side-effects associated with even the most modern atypical medicines.

"That in itself would benefit millions of people around the world.

"But the research also offers a new technique for understanding the workings of the brain that could also be developed for use across broad areas of medicine.

"We really do need to recognise that mental health research is starved of funds compared to other areas of medicine and recognise also that much of it takes place at the frontiers of our understanding which means that results from it could have far-reaching applications."

Tasmanian devil facial cancer origins 'identified'

Since the mid-1990s, Tasmanian devil numbers have crashed

Researchers believe they have identified the source of fatal tumours that threaten to wipe out the wild population of Tasmanian devils.

Writing in Science, an international team of scientists suggest cells that protect nerves are the likely origin of devil facial tumour disease (DFTD).

The disease is a transmissible cancer that is spread by physical contact, and quickly kills the animals.

DFTD has caused the devil population to collapse by 60% in the past decade.

"To look more closely at the tumours' origin, we sequenced the genes that are expressed in this devil cancer and compared them with other genes that are expressed in other devil tissues," explained lead author Elizabeth Murchison, from the Australian National University in Canberra.

She told the Science podcast the team's findings delivered surprising results.

"We found that the tumours expressed genes that were normally only expressed by Schwann cells, which are cells that are found in the peripheral nervous system that protect nerves."

'Genetically distinct'

The researchers sampled 25 different tumours from all over Tasmania, the only place on the planet where the world's largest carnivorous marsupials are found.

DEVILS IN DETAIL Scientific name: Sarcophilus harrisii Devils were given their common name by early settlers, who were haunted by "demonic growls" Largest living carnivorous marsupial Now only found in Tasmania Can live up to five years in wild Weight: male 10-12kg; female 6-8kg They favour habitats where they can shelter by day and scavenge by night

They found that the growths were genetically distinct from their hosts, but were identical to one another.

Dr Murchison, who is also a researcher at Cold Spring Harbor Laboratory, US, said the teams findings had a number of positive outcomes: "Most importantly, this has led to the development of a diagnostic test for the disease.

"Devils are susceptible to a number of different types of cancer. Just like humans, they can get breast cancer, leukaemia, etc - especially in their old age.

"Sometimes it can be difficult to tell the difference between these types of cancer and the transmissible disease.

"Now that we know that these very specific Schwann genes are expressed in the cancer, we can use these genes as diagnostic markers."

DFTD was first described in the mid-1990s, when devils with large facial tumours were photographed in north-eastern Tasmania.

By the end of 2008, the disease - which kills infected animals within nine weeks - had been confirmed at 64 locations, covering more than 60% of the Australian island state's mainland.

Experts warn that without intervention, the disease could wipe out the wild population of the world's largest carnivorous marsupial within decades.

Dr Murchison hoped identifying the catalogue of genes associated with DFTD would lead to the development of vaccines, or possibly therapies.

The disease usually kills infected devils within nine weeks

"As yet, unfortunately, there is nothing we can do to help the devils that have the disease," she said.

"This devil facial cancer is very unusual as it is an infection cancer; it is a little bit like an organ transplant," she said.

"In an organ transplant, you have an organ that is transplanted into an unrelated individual. In the case of the devil cancer, you have a cancer that is transplanted into another unrelated devil through biting.

"One of the big questions about this cancer is why it is not being rejected or being recognised as a foreign graft.

"If we could understand that... we could perhaps use this data to develop a vaccine that could help the devils' immune system reject the cancer before it takes hold."

Sweden culls its resurgent wolves

Grey wolves have made a comeback since hunting was banned

Sweden is to launch its first wolf cull in 45 years, following a decision by parliament to control the species' numbers.

Some 10,000 hunters are reported to be planning to take part - hoping to get a rare opportunity to bag a wolf.

But it is thought there are only about 180-220 wolves in Sweden, and the Environmental Protection Agency has said only 27 can be shot.

Hunters insist there are measures to prevent them shooting too many.

"There's a lot of regulation, hunters have to check the quota every hour," Gunnar Gloersson, of the Swedish Hunters Association, told Radio Sweden.

Nevertheless, the Swedish Society for Nature Conservation is critical of the decision, claiming it is against EU legislation as the Swedish wolf population has not reached a healthy level.

A formal complaint will be issued to the EU Commission, Radio Sweden says.

The hunt will start on 2 January and end before the mating season begins in mid-February.

Snow vital

Wolves were hunted to near extinction in southern Scandinavia until a hunting ban was imposed in the 1970s.

Sweden and Norway have worked together to reintroduce the species to the forests along their border. When Norway culled some wolves in 2001, saying the population had spread too far, Sweden lodged a protest.

But the Swedish parliament recently decided there should be at most 210 wolves in Sweden.

Michael Schneider of the Swedish Environmental Protection Agency says that was the level last year, and since then more than 20 pairs of wolves have had pups.

"We have to remove this increase to keep the population at this level," he said.

Mr Gloersson, of the hunting association, said: "We have a lot of problems with wolves - in reindeer areas, with livestock, and for hunters they kill our valuable dogs."

"Since they came back we have to live with them, but we have to keep their numbers down."

He said the success of the cull would depend on the weather.

"The only easy way to hunt wolves is if we have snow, so the hunters can track them on the snow. If we don't have snow I don't think we'll even be able to reach the quota of 27 wolves," he said.