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dimarts, 22 de desembre de 2015

Quemar combustibles fósiles y talar árboles enfría el planeta [NASA dixit]

Major theories about what causes temperatures to rise have been thrown into doubt after NASA found the Earth has cooled in areas of heavy industrialisation where more trees have been lost and more fossil fuel burning takes place.

Environmentalists have long argued the burning of fossil fuels in power stations and for other uses is responsible for global warming and predicted temperature increases because of the high levels of carbon dioxide produced - which causes the global greenhouse effect.

While the findings did not dispute the effects of carbon dioxide on global warming, they found aerosols - also given off by burning fossil fuels - actually cool the local environment, at least temporarily.

The research was carried out to see if current climate change models for calculating future temperatures were taking into account all factors and were accurate.

A NASA spokesman said: "To quantify climate change, researchers need to know the Transient Climate Response (TCR) and Equilibrium Climate Sensitivity (ECS) of Earth.

"Both values are projected global mean surface temperature changes in response to doubled atmospheric carbon dioxide concentrations but on different timescales.

"TCR is characteristic of short-term predictions, up to a century out, while ECS looks centuries further into the future, when the entire climate system has reached equilibrium and temperatures have stabilised."

The spokesman said it was "well known" that aerosols such as those emitted in volcanic eruptions and power stations, act to cool Earth, at least temporarily, by reflecting solar radiation away from the planet.

He added: "In a similar fashion, land use changes such as deforestation in northern latitudes result in bare land that increases reflected sunlight."

Kate Marvel, a climatologist at GISS and the paper’s lead author, said the results showed the "complexity" of estimating future global temperatures. SEGUIR LEYENDO...
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Genes which make people intelligent have been discovered and scientists believe they could be manipulated to boost brain power.

Researchers have believed for some time that intellect is inherited with studies suggesting that up to 75 per cent of IQ is genetic, and the rest down to environmental factors such as schooling and friendship groups. But until now, nobody has been able to pin-point exactly which genes are responsible for better memory, attention, processing speed or reasoning skills.

Now Imperial College London has found that two networks of genes determine whether people are intelligent or not-so-bright.

They liken the gene network to a football team. When all the players are in the right positions, the brain appears to function optimally, leading to clarity of thought and what we think of as quickness or cleverness. However when the genes are mutated or in the wrong order, it can lead to dullness of thinking, or even serious cognitive impairments.

Scientists believe that there must be a ‘master switch’ regulating the networks and if they could find it, they could ‘switch on’ intelligence for everyone.

“We know that genetics plays a major role in intelligence but until now haven’t known which genes are relevant,” said Dr Michael Johnson, lead author of the study from the Department of Medicine at Imperial College. “This research highlights some of genes involved in human intelligence, and how they interact with each other.

“What’s exciting about this is that the genes we have found are likely to share a common regulation, which means that potentially we can manipulate a whole set of genes whose activity is linked to human intelligence. “Our research suggests that it might be possible to work with these genes to modify intelligence, but that is only a theoretical possibility at the moment – we have just taken a first step along that road.” SEGUIR LEYENDO...





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