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Monday, 4 August 2008

How to predict earthquakes, how to cloak an object and many more

Some ultra cool news from science this week. Check out the bone stuff, very nice :) The quakes also:

  • Curious cloud formations linked to quakes
  • Bones mend faster without marrow
  • Economic crises can have health benefits
  • New material may be step towards 3D invisibility cloak

Curious cloud formations linked to quakes

Geophysicists Guangmeng Guo and Bin Wang of Nanyang Normal University in Henan, China, noticed a gap in the clouds in satellite images from December 2004 that precisely matched the location of the main fault in southern Iran before each of two large earthquakes occurred. It stretched for hundreds of kilometres, was visible for several hours and remained in the same place, although the clouds around it were moving. At the same time, thermal images of the ground showed that the temperature was higher along the fault. Sixty-nine days later, on 22 February 2005, an earthquake of magnitude 6.4 hit the area, killing more than 600 people.

In December 2005, a similar formation again appeared in the clouds for a few hours. Sixty-four days later, an earthquake of magnitude 6 shook the region (International Journal of Remote Sensing, vol 29, p 1921).

Guo and Wang suggest that an eruption of hot gases from inside the fault could have caused water in the clouds to evaporate. Another idea is that ionisation may be involved: Friedemann Freund at the NASA Ames Research Center in Moffett Field, California, recently demonstrated that when rocks are squeezed, positively charged ions form in the air above. The trouble is that ions usually help to form clouds, not dissipate them.

The authors say that if recognisable cloud formations precede large quakes, they could be used for prediction, but other seismologists are scepticalsource

My comment: That's awesome for many reasons. It's easy, not harmful to the world and it makes sense. And my experience shows that even when you don't know why something works, it still may very well works. So i hope this is further investigated.

New material may be step towards 3D invisibility cloak

A California nanotechnology research lab says it has created the first 3D material able to bend light in the opposite direction to natural materials. But some other specialists in the field remain sceptical about the claim.

Physicists have in recent years made it possible to bend, or refract, light in the opposite direction to any natural materials. These metamaterials make it possible to create invisibility cloaks that hide an object by steering light around it.

The refractive index of a material is a measure of how it bends light and for natural materials it is always positive. Metamaterials, though, can have negative refractive indexes.

This is achieved with tiny periodic structures that interact with the electric and magnetic fields that comprise light. The repeating structures need to be smaller than the light waves themselves, something that has limited them to long-wavelength light, or microwaves.

So far, researchers have created negative refractive-index materials and even an "invisibility cloak" for visible light and microwaves. But they have all been flat, working only in two dimensions.

Now Jason Valentine, a graduate student in the nano-engineering lab at the University of California at Berkeley, US, claims to have made a 3D metamaterial with a negative refractive index.

Valentine's "prism" is made from 21 alternating layers of silver and magnesium fluoride, arranged in a "fishnet" structure. He claims that the refractive index is negative in a small region of the near-infrared spectrum.

Gunnar Dolling of the University of Karlsruhe, Germany, has made a flat negative refractive-index material for light on the boundary between red and infrared light. He is unconvinced by Valentine's claims, he says.

Dolling and colleagues found that the complex interactions between light waves and such metal-based metamaterials can deflect a light beam the "wrong way" without a negative refractive index.

"You can only measure a negative refractive index by measuring the phase velocity", meaning the actual speed of light in the medium, he told New Scientist.

A paper on the negative prism was presented on 8 May at the Quantum Electronics and Laser Science Conference in San Jose, California, US. source

My comment: Cool, that's all I can say. I don't know what use that could have, but it just so reminds me of SG :)

Bones mend faster without marrow

A new study in rats suggests that removing some bone marrow with a syringe could kick-start rapid self-healing in weakened or fractured bones, if followed up with injections of a bone growth hormone.

Agnes Vignery’s team at Yale University anaesthetised a group of rats and drilled into the left thigh-bone of each animal before syringing out the bone marrow. Some of the rats received daily doses of parathyroid hormone (PTH), a clinically approved drug that encourages the growth of new bone.

After two weeks, X-rays of the rats showed that new bone had begun to form in the bone marrow cavity. In most rats, the new bone was short-lived - by the third week, marrow began to reappear and any new bone cells were reabsorbed to make room. But in the rats treated with PTH, new bone continued to grow in the cavity into the third week and the marrow did not return.

Vignery’s team also discovered that the de-marrowed thighbones of the PTH-treated rats were stronger than their other legs, and the legs of rats not given PTH (Tissue Engineering, DOI: 10.1089/ten.2007.0261).

The study suggests that bone marrow usually inhibits the formation of new bone, says Vignery, and that simply removing the marrow and using drugs to encourage new bone growth could help treat weakened or broken bones.

“At first glance this appears counter-intuitive,” says Brendon Noble at the University of Edinburgh, UK, since bone marrow generates the stem cells that would usually help repair bones. However, periosteum cells in the membrane that lines the outside of bones also have regenerative powers.

Bone marrow is also needed to produce new blood cells, but Vignery says that removing it from damaged bones shouldn’t affect a person’s health, so long as marrow remains in other bones.

Warren Levy of Unigene Laboratories, in Fairfield, New Jersey, which provided Vignery’s team with PTH for the study, believes the procedure could radically change the way patients are treated, particularly those with hip fractures. Such fractures often require major surgery, which is expensive and can be life-threatening in elderly patients. “Instead, if an X-ray reveals a fracture, you could go in with a needle right there in the doctor’s suite and do without surgery,” Levy says.

The patient would then be sent home with a prescription for PTH, and new bone would grow in the marrow cavity, repairing the fracture from the inside. source article

My comment: That's ultra cool. I love it, because it's so beautiful and helpful! I hope it works, because it will significantly help recovery of broken bones. Cool, huh?

Stress increases risk of stillbirth

IF YOU are pregnant, think twice before taking on an extra project at work. Severe stress, even in the short term, may almost double the risk of having a stillbirth - although stillbirths are rare.

Stress has been linked to premature birth, high blood pressure and other health problems associated with stillbirths. Now Kirsten Wisborg from the Aarhus University Hospital in Denmark and colleagues have shown that stress increases the risk even when women don't have these problems.

The researchers analysed questionnaires filled in by over 19,000 women during the last three months of pregnancy ... source

My comment: I don't know why if stress is such a major problem for our health, we're not taught in school how to handle it and why employers don't pay more money for stressful jobs.

Economic crises can have health benefits

If everyone lost just 4 or 5 kilograms, mortality rates would drop dramatically. At least that's one lesson from the economic crisis Cuba suffered in the 1990s.

When the Soviet empire began to unravel in 1989, Cuba was hit with serious food and fuel shortages. From 1991 to 1995, people were getting only about 1800 calories a day and had to walk or cycle wherever they needed to go.

The result was an average drop in body mass index of 1.5 units, and a halving of the obesity rate to just 7 per cent. In the years that followed, deaths from potentially fatal diseases fell dramatically - diabetes by 51 per cent, coronary artery disease by 35 per cent and stroke by 20 per cent (Canadian Medical Association Journal, vol 178, p 1032).

In countries like Canada and the US, where obesity rates are around 30 per cent, the gains from population-wide weight loss would be even greater, the authors argue. source

My comment: That's ultra cool! I love it. So people, eat less, walk more and you'll feel great.

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