the-BA : Science News Digest

Boy enjoying the Sun (Image copyright: istockphoto.com)

In the science news this week: the mass of the biggest known black hole in the Universe is measured, we're advised to enjoy a little sunshine to help fight cancer and the blood-red glow of the 'cursed' Hope Diamond is explained...

The Guardian reported that new research from the University of Kansas suggests that a way to predict epileptic seizures could be developed with the help of earthquake-prediction techniques.

Comparison of earthquake seismological data with brain electrical activity before and during seizures showed that the frequency of both earthquakes and epileptic seizures can be described by ‘power laws’. These laws can often explain the frequency of apparently random events and in the case of earthquakes link the size of individual earthquakes with the time between quakes of the same size.

In a paper uploaded to the Arxiv website (where scientists swap research findings that have not yet undergone peer-review), neurologist Ivan Osorio said the work ‘suggests a novel research direction for the prediction of seizures based on the notion that seizures beget seizures’.
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A new generation of nuclear power stations for the UK received formal government backing, reported BBC News. Business Secretary John Hutton told MPs that nuclear power was a ‘tried and tested’ safe technology which had a role to play ‘in this country's future energy mix alongside other low-carbon sources’. He made assurances that private operators would be expected to meet the full cost of building and decommissioning plants (which would be built at or near existing reactors), and disposing of waste.

Now, the next generation of nuclear power station will be chosen from four models after an assessment of their safety and efficiency by the Nuclear Installations Inspectorate, the Health and Safety Executive and the Environment Agency. Each is safer and more environmentally friendly than current reactors in Britain, with safety features based on natural forces such as gravity or convection rather than mechanical or electronic systems, and a significant reduction in the amount of radioactive waste generated.

The Times reported that the new models would be assessed over the next three years and that licensing and planning could be complete by about 2012. Construction is likely to then take another four years. This would be consistent with Hutton’s hope that the first new reactors would be generating electricity by 2018.
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A study published in the journal Science has shown that the disappearance of large animals such as elephants from the eastern African savanna could, ironically, result in damage to the acacia trees they eat and even affect ants – serving as a cautionary tale of how the effects of humans on an ecosystem can have unexpected impacts.

Four species of ants rely on these trees for food (nectar) and shelter, while protecting the trees from browsing munching animals. Researchers from the University of Florida found that when they fenced off patches of acacias over a period of ten years, preventing large mammals from feeding on them, the trees looked less healthy than those still at threat from being eaten.

They discovered that the shift in the balance led to a decrease in the size of ant colonies and that a parasitic ant species became dominant, leading to more attacks by stem-boring beetles and reduced tree growth and survival.

Todd Palmer told the Telegraph: ‘Throughout sub-Saharan Africa these large mammals are threatened by human population growth, habitat fragmentation, over-hunting, and other degradation, so we have to wonder how their loss will affect these ecosystems.

‘It’s important that conservation biologists continue to learn not only about individual species, but also the complex web of interactions in which these species are embedded, when thinking about how to maintain the integrity of ecological systems.’
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Another Telegraph article focussed on the call by a biologist for human population control to help save coral in the Caribbean, after a study of 322 sites across 13 countries revealed that reefs are still being degraded due to coastal development, even in protected areas.

Monitoring of the coral reefs was combined with data analysis of human population density, coastal development, agricultural land use and data on environmental and ecological factors such as coral diseases, temperature and hurricanes.

Large numbers of species are threatened by the loss of coral reefs, which have decreased by about 80 per cent in the past three decades in the Caribbean alone. The latest study, published in the Proceedings of the Royal Society of London, Biological Sciences, clearly showed that the main cause of the loss of coral and fish was the number of people living in close proximity to reefs, along with an increase in seaweed. Further analysis revealed that it was coastal development, with the increase in sewage and fishing pressure that this brings, that was at fault.

Study author Camilo Mora, of Dalhousie University, Canada, said: ‘The future of coral reefs in the Caribbean and the services they provide to a growing human population depend on how soon countries in the region become seriously committed to regulating human threats.’ Dr Mora added that we shouldn’t be afraid to talk about population regulation and that strategies on family planning have proven successful in many cases.
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At the meeting of the American Astronomical Society in Austin, Texas, astronomers outlined their discovery of ancient precursors to spiral galaxies such as our own Milky Way. These Lyman alpha-emitting galaxies are about one-tenth of the size of the Milky Way and were among the first in the Universe to form.

According to cosmological theory, these small galaxies merged to form larger galaxies. However, other research presented at the meeting indicates not all galaxies form this way – a class of massive disc galaxies that existed in the early Universe must instead have formed from a massive gas cloud collapsing in on itself.
(Read more at BBC News)
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Also at the meeting, reported BBC News, a team of astronomers from Finland revealed that they have measured the mass of a black hole 18 billion times more massive than our Sun, making it the biggest known black hole in the Universe.

Since it is orbited by a smaller black hole, they were able to make an extremely accurate measurement. It was also the first time Einstein’s theory of gravity could be tested in such a strong gravitational field. The researchers showed that the theory could give the correct orbital behaviour of the binary system.
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The most detailed map to date of dark matter in the Universe was also unveiled at the meeting, reported the Guardian. The presence of dark matter (which doesn’t emit or reflect radiation) was inferred by its gravitational effects on the light emitted by surrounding galaxies.

The scientists from the Universities of Nottingham and British Columbia combined 80 images of the Abell 901 and 902 supercluster of galaxies, 2.6 billion light years from Earth, made by the Hubble space telescope in 2006. The resulting map is 2.5 times sharper than the previous one generated using ground-based instruments.
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While time in the Sun may be somewhat wishful thinking at this gloomy time of year, according to Dr Richard Setlow, the scientist who first alerted the world to the role of sunlight in skin cancer, we could benefit from a little more sunshine. This is because vitamin D (which is produced by the skin when exposed to sunlight) plays a protective role in a number of diseases, including internal cancers such as colon, breast and lung, and ‘advice to avoid sun exposure may be causing more harm than good in some populations’.

Dr Setlow and colleagues at the Institute for Cancer Research in Oslo modelled how much sunshine people receive depending the latitude where they live, and the incidence and survival rates for various internal cancers in people living at these latitudes.

They found that people living in Australia produce 3.4 times more vitamin D in response to sun exposure than people in the UK, and 4.8 times more than people in Scandinavia. And, while the incidence of major cancers increased from north to south, resulting death rates were significantly less in the south.

Many people in the UK are not getting enough vitamin D – approximately 90 per cent of UK adults get less than three micrograms of the vitamin a day, compared to the recommended 5 to 25 micrograms.

Ed Yong, a health information manager at Cancer Research UK, said that it is possible for people to gain the benefits of the sun without the risks: ‘It’s becoming increasingly clear that vitamin D does have some benefits in terms of reducing people’s risks of cancer. [But] the amount of sun exposure it takes to produce enough vitamin D is always less than the amount it takes to tan or burn.

‘There should always be an achievable balance between getting enough vitamin D to reduce your risk of [cancer], while not getting enough sun exposure to tan or burn and thus increase your risk of skin cancer.’
(Read more in the Guardian and Times)
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And finally…

The mystery of the famed 45.52-carat, deep-blue Hope Diamond that is supposedly cursed could be solved thanks to a discovery reported in the journal Geology.

The diamond gives off an eerie blood red glow for several seconds after exposure to ultraviolet light and was supposedly cursed after being stolen from the eye of a sculpture of the Hindu goddess Sita. While all blue diamonds glow in ultraviolet light, as a result of the boron present (the element that is also responsible for the blue colour in normal light), most glow white or blue. The reason the Hope Diamond glows red is because there is a mix of boron and nitrogen.

Researchers are able to use the phosphorescence – the different glows and rates of fading – to help ‘fingerprint’ blue diamonds to establish their source and whether they are real or artificial. This could help shed light on the question of whether the Hope was cut from a bigger stolen gem, and identify other diamonds cut from the same source.

The technique will also have practical applications in verifying diamonds’ authenticity, reported the Telegraph. ‘Synthetic diamonds are typically marketed as such, and the intent is to offer a more cost effective choice rather than to deceive,’ says Jeffrey Post, curator at the Smithsonian Institution where the Hope Diamond is held. ‘Once they are in the market, however, they might easily mix with the natural stones, and it is, therefore, necessary to have a way to distinguish natural from synthetic.’