Tuesday, March 4, 2008

140-year-old math problem solved by researcher

A problem which has defeated mathematicians for almost 140 years has been solved by a researcher at Imperial College London.

Professor Darren Crowdy, Chair in Applied Mathematics, has made the breakthrough in an area of mathematics known as conformal mapping, a key theoretical tool used by mathematicians, engineers and scientists to translate information from a complicated shape to a simpler circular shape so that it is easier to analyse.

This theoretical tool has a long history and has uses in a large number of fields including modelling airflow patterns over intricate wing shapes in aeronautics. It is also currently being used in neuroscience to visualise the complicated structure of the grey matter in the human brain.

A formula, now known as the Schwarz-Christoffel formula, was developed by two mathematicians in the mid-19th century to enable them to carry out this kind of mapping. However, for 140 years there has been a deficiency in this formula: it only worked for shapes that did not contain any holes or irregularities.

Now Professor Crowdy has made additions to the famous Schwarz-Christoffel formula which mean it can be used for these more complicated shapes. He explains the significance of his work, saying:

"This formula is an essential piece of mathematical kit which is used the world over. Now, with my additions to it, it can be used in far more complex scenarios than before. In industry, for example, this mapping tool was previously inadequate if a piece of metal or other material was not uniform all over - for instance, if it contained parts of a different material, or had holes."

Professor Crowdy's work has overcome these obstacles and he says he hopes it will open up many new opportunities for this kind of conformal mapping to be used in diverse applications.

"With my extensions to this formula, you can take account of these differences and map them onto a simple disk shape for analysis in the same way as you can with less complex shapes without any of the holes," he added.

Professor Crowdy's improvements to the Schwarz-Christoffel formula were published in the March-June 2007 issue of Mathematical Proceedings of the Cambridge Philosophical Society.

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Be a macgyver: coolest fire making tricks

Below I assembled a list of the absolute coolest ways to make fire, when you have just a couple of weird items! If you’re alone in the desert, playing ’survivor’ with your friends or just wanna impress some girls - this is perfect for you. Also, there’s some very interesting scientific stuff in there, which I’ll expand about later in greater detail. Well, without further ado, here it is - the coolest ways to make fire:

1. Using a potato: potatoes are great. They’re very tasty, and apparently quite helpful when it comes to making fire. All you need is a potato cut in half, some wires and a lot of ambition.


2. Using coke & chocolate: if you don’t have a potato, you can always try a can of coke and some chocolate bars. I know that sounds like a great recipe for a party, but it can also be used to make fire in a really neat way.


3. Without matches or a lighter: Now here’s the real treat. You don’t have matches, or a lighter (or coke, chocolate and potatoes. This means you’re in real trouble and this might actually be useful to you). What you can do is use a simple battery and some fine steel wool. Next thing you know you’re caveman with some amazing fire surrounding you.


4. Using friction (the Masai way): Friction, the ancient method our ancestors used, is still not forgotten. It’s effective, cheap, *always* available and very straight-forward.


5. Using a condom: Mmm. This is the sexy way. If your girlfriend dumped you, or you’re a lonely wolf reading blogs at night, this one’s for you. Finally something to do with the old dusty condoms of yours. Be careful though, it keeps your most important organs safe.


That’s it, now go burn up your house!

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Nanomagnets 'could target cancer'

The tiny magnetic particles are produced in bacteria
Tiny magnets made by bacteria could be used to kill tumours, say researchers.

A team at the University of Edinburgh has developed a method of making the nanomagnets stronger, opening the way for their use in cancer treatment.

The bacteria-produced magnets are better than man-made versions because of their uniform size and shape, the Nature Nanotechnology study reported.

It is hoped one day the magnets could be guided to tumour sites and then activated to destroy cancerous cells.

The bacteria take up iron from their surroundings and turn it into a string of magnetic particles.

They use the chains of particles like a needle of a compass to orientate themselves and search for oxygen-rich environments.

For nanoparticles to be used in medicine you need them to be a very uniform size and shape and bacteria are very good for that
Dr Sarah Staniland, study leader

There has been a lot of interest in their potential application in medicine, but how useful they could be will depend on the strength of the magnets.

Scientists at Edinburgh University grew the bacteria in a mixture that contained more cobalt than iron.

The addition of cobalt in the nanomagnets made them 36-45% stronger.

This meant they stayed magnetised longer when taken out of a magnetic field.

'Exciting research'

The ability of the nanomagnets to remain magnetised opens the way for their use in killing tumour cells, the researchers said.

They could be guided to the site of a tumour magnetically.

Once there, applying an opposite magnetic field would cause the nanomagnets to heat up, destroying cells in the process.

They could also potentially be used to carry drugs directly to the cancerous tissue.

Study leader, Dr Sarah Staniland, a research fellow at the University of Edinburgh, said: "For nanoparticles to be used in medicine you need them to be a very uniform size and shape and bacteria are very good for that.

"This increases the scope for their use in cancer.

"You would move them with a normal magnetic field and then heat them with the opposing field."

Liz Baker, Cancer Research UK's science information officer, said: "Targeting treatments specifically to cancer cells is an exciting area of research, but in this case work is still at a very early stage.

"It will be interesting to see if further research into nanomagnets will provide us with a new and effective anti-cancer therapy."

The research was carried out alongside scientists at Daresbury Laboratory in the UK and the Institut Laue-Lengevin in Grenoble, France.

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Jungle frog’s anti-infection agent may help millions of diabetics

A nocturnal frog that dwells in the ponds and lagoons of the Amazon could prove to be an unlikely lifesaver for millions of people suffering from diabetes, researchers say.

The South American “paradoxical frog” (Pseudis paradoxa) owes its name to an uncanny ability to shrink as it grows older.

Scientists studying the properties of its slimy skin have found a substance that can stimulate the release of insulin, the vital hormone that is deficient in sufferers from diabetes.

Scientists have made an artificial copy of the peptide, a protein-building block that protects the frog from infection, and have suggested that it could be used to boost insulin production in people with Type 2 diabetes.

In laboratory tests, researchers found that the paradoxical frog’s peptide, known as pseudin-2, increased release of insulin in cultured cells by 50 per cent. However, more work must be carried out before the therapy is ready to be tested on human patients.

Currently there are 2.3 million diagnosed sufferers from diabetes in the UK, most of whom have the Type 2 form of the disease. Usually occurring in middle age, Type 2 diabetes is strongly associated with lifestyle factors such as obesity and develops because the body does not produce enough insulin or becomes resistant to the concentrations available.

The joint team from the University of Ulster in Northern Ireland and United Arab Emirates University believe that a synthetic version of pseudin-2 could join a new class of medicines, called incretin mimetics, that help diabetics to control their condition when dietary changes or other medicines have failed.

The skin secretions of frogs and other amphibians are being investigated as a rich source of biological agents that may lead to new drugs.

Byetta, a diabetes drug based on the saliva of an endangered lizard, the Gila monster of North America, is already available in the UK. But scientists believe that the frog’s secretions could be even more effective. Paradoxical frogs are one of the few animals whose young are bigger than their parents, with tadpoles growing up to 27cm (11in) in length while the mature frogs are only about 4cm long.

Yasser Abdel-Wahab, senior lecturer in biomedical sciences at the University of Ulster, said that the chemistry of amphibian peptides was very similar to that of some mammalian counterparts that help to regulate blood sugar. He studied samples from several different species of frog before finding the desired effect, he said.

“We are at an exciting stage with this research,” he said. “We have tested a more potent synthetic version of the pseudin-2 peptide and have found that it has the potential for development into a compound for the treatment of Type 2 diabetes. Now we need to take this a step further and put our work into practice to try and help people with Type 2 diabetes.

“More research is needed, but there is a growing body of work around natural anti-diabetic drug discovery that is already yielding fascinating results.”

Further details of the research will be presented today at the Diabetes UK Annual Professional Conference in Glasgow.

Diabetes is a condition in which the amount of glucose (sugar) in the blood is too high because the body cannot use it properly. Normally insulin is produced by cells in the pancreas in the right amounts needed to regulate blood sugar levels.

In Type 2 diabetes, the beta cells that produce insulin may fail to respond adequately to changes in blood glucose concentrations after a meal. Type 1, also known as insulin-dependent diabetes, is a less common disease that results in the complete destruction of insulin-producing cells.

Douglas Smallwood, Chief Executive of Diabetes UK, said: “We welcome this innovative research that could benefit some of the two million people in the UK with Type 2 diabetes.

“Although it can be managed with diet and physical activity, Type 2 diabetes is progressive and may require tablets and/or insulin to control it effectively. Good diabetes control reduces the risk of complications including blindness, heart disease, kidney problems and amputation, so new treatments are vital.”

Short hop to healing

— The tadpoles of the paradoxical frog, right, grow to 27cm (11in), more than three times larger than their parents, which are 4cm to 6.5cm in length. As it takes on its adult form, the frog shrinks to its mature size. Scientists have yet to come up with a biological explanation but the tadpoles’ giant size may be the result of exposure to prolactin, a hormone.

— Pseudis paradoxa is found in permanent ponds with floating vegetation in South America and Trinidad. The frog remains in the water most of the time, often with just its bulging eyes poking above the surface.

— Feeding on larvae, small insects and tiny invertebrates, the frog is mainly active at night except during its breeding season, when the males may make loud, croaking calls at any time. These calls attract the females to come to the males and mate with them. Then they lay their eggs among the plants in the water. The eggs, grouped in clusters, hatch into tadpoles.

— Much of the length of the tadpole is in its tail and once that shrinks away, the froglet is much smaller. Most frogs and toads are at about 10-20 per cent of their adult size when they metamorphose.

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Lunar eclipse may shed light on climate change

Last month's lunar eclipse not only treated skygazers to a ruddy view of the Moon – it revealed that Earth's atmosphere contains little light-blocking volcanic dust.

Some researchers say the low volcanic dust levels in the atmosphere over the last dozen years could be contributing to global warming, but others dispute the claim.

During a lunar eclipse, Earth blocks sunlight from reaching the Moon directly. But some sunlight still gets through, refracted through Earth's atmosphere. The amount varies, depending mainly on how much dust from volcanic eruptions is floating around at high altitudes.

Because dust can block sunlight from passing through the atmosphere, more dust makes for a darker Moon during lunar eclipses. "All the big dimmings of the Moon during eclipses can be attributed to specific volcanoes," says Richard Keen of the University of Colorado in Boulder, US.

Keen and his collaborators have charted the brightness of eclipses back to 1960 and for a few years around the time of the 1883 eruption of Indonesia's Krakatoa volcano.

They are using the eclipse data to track changes in the opacity of Earth's atmosphere. While most of the light deflected by particles in the atmosphere is just temporarily diverted and eventually reaches the Earth's surface, the effects of atmospheric dust can have a significant, if temporary, impact on the climate, Keen says.

Global average

Earth-orbiting satellites can measure atmospheric opacity, but only for a small part of the atmosphere at any given time. A lunar eclipse, on the other hand, conveniently gives an average over all latitudes, Keen says. Eclipse measurements are also easily compared with old eclipse records, which extend back much further in time than the satellite measurements, he says.

The most recent lunar eclipse, on 20-21 February, was a bright one, measuring a 3 – the second-brightest level – on an eclipse-rating scale that ranges from 0 to 4.

That is in line with eclipse data taken since 1995. In that time, the stratosphere has been especially clear, with very little haze-producing volcanic activity compared to the previous three decades, from 1965 to 1995, Keen says.

Because more sunlight is reaching the surface, Earth should be 0.1 to 0.2° Celsius warmer in recent years than it was back in the late 1960s, Keen and his colleagues calculate. Over the same period, the average surface temperature of the Earth has risen by about 0.6° C.

Many factors

According to the scientists that make up the Intergovernmental Panel on Climate Change (IPCC), which reports to the United Nations, most of the warming since the mid-20th century is due to the greenhouse gases released by human activity. Other factors, including fluctuating patterns in ocean circulation and slight changes in the Sun's brightness, also influence the climate.

"All of these have been contributing to a warming, adding on top of each other," Keen told New Scientist. "The difficulty is, of course, what are the relative magnitudes [of these effects]," he says.

Susan Solomon of the US National Oceanic and Atmospheric Administration in Boulder, Colorado, a member of the Nobel-prize-winning team that put together the 2007 IPCC report, says atmospheric haze, including haze from volcanoes, was included in computer models used for the report.

But she disputes Keen's conclusions. "There's no evidence for a significant warming trend over the last several decades [due to a decline in volcanic haze]," she told New Scientist. "In fact, it's exactly the opposite."

Ocean heating

The amount of haze in the stratosphere has been higher – blocking more sunlight – in the past 40 years compared to the 20 years before that, she says. So over the past 60 years, there would have been a slight cooling trend if volcanic haze were the only influence on climate, she says.

Keen acknowledges that depending on the period chosen, volcanic haze can give a cooling rather than a warming trend. But he argues that the relatively long period with a clear atmosphere since 1995 could be having a big impact on climate, especially if the extra sunshine reaching the Earth's surface could create subtle, longer-term warming effects through the heating of ocean water, as some scientists propose.

He is now compiling more precise estimates of the brightness of the most recent eclipse by comparing the Moon's brightness to that of reference stars during the eclipse. This will allow the amount of haze in the stratosphere during the eclipse to be calculated more precisely.

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