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Earth”s twisted heart ‘dictates’ day’s length

May 6, 2010 By vani Leave a Comment

London, May 6 (ANI): Fluctuations at Earth”s core decide the length of the day, according to scientists.

To come up with the finding, Nicolas Gillet of the University of Joseph Fourier in Grenoble, France, and colleagues, modelled fluid behaviour in the Earth”s core based on measurements of fluctuations in the magnetic field.

According to Gillet, the innermost region of the Earth”s outer core periodically flows faster or slower, and this action “tugs” at the planet”s magnetic field.

New Scientist reports, “the field then pulls the region back towards its original position. But the effect ripples outward, changing the core”s rate of rotation layer by layer.

“The researchers calculated how this would affect the rotation rate of the whole planet, which would compensate to conserve angular momentum.

“They found the day length varies by 0.4 milliseconds over a six-year period. This fits with day-length measurements taken between 1925 and 1997.

“The twisting had previously been blamed for a 60-year cycle in day length, but the rate of rotation found in this study suggests it is not the culprit, says Jon Mound at the University of Leeds, UK.” (ANI)

Filed Under: International News Tagged With: Angular Momentum, colleagues, culprit, Earth Day, fluctuations, Grenoble France, Innermost Region, Joseph Fourier, Length Measurements, magnetic field, Milliseconds, New Scientist, Nicolas Gillet, Outer Core, ripples, Rotation Rate, Scientists, Tugs, university of leeds, university of leeds uk

””Junk”” DNA behind cancer growth

May 3, 2010 By vani Leave a Comment

London, May 3 (ANI): Scientists have discovered a new driving force behind cancer growth.

Researchers from the University of Leeds, UK, the Charite University Medical School and the Max Delbruck Centre for Molecular Medicine (MDC) in Berlin, Germany, have identified how ””junk”” DNA promotes the growth of cancer cells in patients with Hodgkin””s lymphoma.

Professor Constanze Bonifer (University of Leeds) and Dr Stephan Mathas (Charite, MDC) who co-led the study suspect that these pieces of ””junk”” DNA, called ””long terminal repeats””, can play a role in other forms of cancer as well.

The researchers uncovered the process by which this ””junk DNA”” is made active, promoting cancer growth.

“We have shown this is the case in Hodgkin””s lymphoma, but the exact same mechanism could be involved in the development of other forms of blood cancer. This would have implications for diagnosis, prognosis, and therapy of these diseases,” said Bonifer.

””Long terminal repeats”” (LTRs) are a form of ””junk DNA”” – genetic material that has accumulated in the human genome over millions of years.

Although LTRs originate from viruses and are potentially harmful, they are usually made inactive when embryos are developing in the womb.

If this process of inactivation doesn””t work, then the LTRs could activate cancer genes, a possibility that was suggested in previous animal studies.

This latest study has now demonstrated for the first time that these ””rogue”” active LTRs can drive the growth of cancer in humans.

The work focused on cancerous cells of Hodgkin””s lymphoma that originate from white blood cells (antibody-producing B cells).

Unusually, this type of lymphoma cell does not contain a so-called ””growth factor receptor”” that normally controls the growth of other B-cells.

They found that the lymphoma cells”” growth was dependent on a receptor that normally regulates the growth of other immune cells, but it is not usually found in B-cells.

However in this case, the Hodgkin-/Reed Sternberg cells ””hijacked”” this receptor for their own purposes by activating some of the ””junk DNA””.

In fact the lymphoma cells activated hundreds, if not thousands, of LTRs all over the genome, not just one.

Hodgkin-/Reed Sternberg cells may not be the only cells that use this method to subvert normal controls of cell growth.

The researchers found evidence of the same LTRs activating the same growth receptor in anaplastic large cell lymphoma, another blood cancer.

The consequences of such widespread LTR activation are currently still unclear, according to the study””s authors.

Such processes could potentially activate other genes involved in tumour development. It could also affect the stability of chromosomes of lymphoma cells, a factor that may explain why Hodgkin-/Reed Sternberg cells gain many chromosomal abnormalities over time and become more and more malignant.

The study has been published in Nature Medicine. (ANI)

Filed Under: International News Tagged With: B Cells, Blood Cancer, cancer cells, cancer genes, cancer growth, cancerous cells, Growth Factor Receptor, Growth Researchers, Hodgkin S Lymphoma, human genome, immune cells, Junk Dna, lymphoma cells, Mathas, Max Delbruck, Molecular Medicine, university medical school, university of leeds, university of leeds uk, white blood cells

Invading black holes cause ‘cosmic flashes’

September 19, 2009 By admin Leave a Comment

Washington, September 19 (ANI): Mathematicians at the University of Leeds, UK, have determined that cosmic flashes, known as gamma ray bursts, are produced by jets of plasma that originate from invading black holes.

Gamma ray bursts are beams of high-energy radiation that are similar to the radiation emitted by explosions of nuclear weapons.

The orthodox model for this cosmic jet engine involves plasma being heated by neutrinos in a disk of matter that forms around a black hole, which is created when a star collapses.

But, mathematicians at the University of Leeds, have come up with a different explanation: the jets come directly from black holes, which can dive into nearby massive stars and devour them.

Their theory is based on recent observations by the Swift satellite, which indicates that the central jet engine operates for up to 10,000 seconds – much longer than the neutrino model can explain.

Mathematicians believe that this is evidence for an electromagnetic origin of the jets, that is, that the jets come directly from a rotating black hole, and that it is the magnetic stresses caused by the rotation that focus and accelerate the jet’s flow.

For the mechanism to operate, the collapsing star has to be rotating extremely rapidly.

This increases the duration of the star’s collapse as the gravity is opposed by strong centrifugal forces.

One particularly peculiar way of creating the right conditions involves not a collapsing star, but a star invaded by its black hole companion in a binary system.

The black hole acts like a parasite, diving into the normal star, spinning it with gravitational forces on its way to the star’s centre, and finally eating it from the inside.

“The neutrino model cannot explain very long gamma ray bursts and the Swift observations, as the rate at which the black hole swallows the star becomes rather low quite quickly, rendering the neutrino mechanism inefficient, but the magnetic mechanism can,” said Professor Komissarov from the School of Mathematics at the University of Leeds.

“Our knowledge of the amount of the matter that collects around the black hole and the rotation speed of the star allow us to calculate how long these long flashes will be – and the results correlate very well with observations from satellites,” he added. (ANI)

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Traces of microbes in shallow ice layers may help find life on icy worlds

June 27, 2009 By admin Leave a Comment

Washington, June 26 (ANI): A new research has indicated that living microorganisms and the food that sustained them can be detected in shallow ice layers, which will help find life on icy worlds.

The research is a part of the Project SLIce, which means, Signatures of Life in Ice.

Dominique Tobler and Jennifer Eigenbrode of NASA Goddard Space Science Laboratory, and Liane Benning of the University of Leeds, UK, show that not only living micro-organisms, but also traces of long-dead ones, and the food that sustained them can be detected in shallow ice layers, using methods rigorously tested in one of our own planet’s most extreme environments.

“With SLIce, we wanted to figure out the nature of the organic matter in ice and how what we find on Earth can be the basis for comparisons with organic matter on Mars,” explained Benning.

“The organic matter we find could be alive or dead, representing extant or extinct life, or even the nutrients that made life possible, and we want to identify the biological signals that point towards ice-dwelling life,” she added.

The SLIce team went to a glacial region of Svalbard to try taking ice samples in exactly the way it would be done on Mars, using a sequence of procedures and tests that they had developed as part of the AMASE project, a long-running international research program that has established Svalbard as a test bed for planetary exploration.

“We’re using sample devices, primarily to be operated from a rover, but we’re also testing how we go about taking and testing samples and keeping them separate,” said Benning.

“For SLIce, we applied the protocol we had developed to take ice cores, process them and analyze them in the field just as would happen on a rover on Mars, and then of course we took them back to the lab and did a much wider range of tests, so we really knew what we had found,” she said.

“There could be microbes living in the ice, but there could also be the dead bodies of microbes that used to live there, and there could be biological molecules that blew in from dust and micrometeorites. We need to identify what we’ve got, so that we know what it’s telling us,” she added. (ANI)

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Industrialization of China increases fragility of global food supply

January 25, 2009 By Rajesh Leave a Comment

Washington, Jan 22 (ANI): A new research by the University of Leeds, UK, has determined that industrialization of China is increasing the fragility of global food supply, with reports indicating that global grain markets are facing a breaking point.

Experts predict that if China’s recent urbanisation trends continue, and the country imports just 5 percent more of its grain, the entire world’s grain export would be swallowed whole.

The knock-on effect on the food supply – and on prices – to developing nations could be huge.

Sustainability researchers have conducted a major study into the vulnerability of Chinese cropland to drought over the past 40 years, which has highlighted the growing fragility of global grain supply. Increased urban development in previously rich farming areas is a likely cause.

“China is a country undergoing a massive transformation, which is having a profound effect on land use,” said Dr Elisabeth Simelton, research fellow at the Sustainability Research Institute at the University of Leeds, and lead author of the study.

“Growing grain is a fundamentally low profit exercise, and is increasingly being carried out on low quality land with high vulnerability to drought,” she added.

The study looked at China’s three main grain crops; rice, wheat and corn, to assess how socio-economic factors affect their vulnerability to drought.

Researchers compared farming areas with a resilient crop yield with areas that have suffered large crop losses with only minor droughts.

They found that traditionally wealthy coastal areas are just as susceptible to drought as areas with poor topography in the east of the country.

At the moment, the Chinese government claims that China is 95 percent self sufficient in terms of grain supply.

If China were to start importing just 5 percent of its grain, the demand would hoover up the entire world’s grain export. The pressure on grain availability for international grain markets could, in turn, have a huge knock-on effect.

Poorer countries are particularly vulnerable, as demonstrated by the 2007-2008 food crisis.

Published in the journal Environmental Science and Policy, the study used provincial statistics of harvests and rainfall together with qualitative case studies to establish the differences between land that is sensitive to drought and land that is not.

“One aim of this research is better understanding of the socio-economic responses to difficult conditions so that we can improve models of climate change,” said Dr Simelton. (ANI)

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Earth”s twisted heart ‘dictates’ day’s length

””Junk”” DNA behind cancer growth

Invading black holes cause ‘cosmic flashes’

Traces of microbes in shallow ice layers may help find life on icy worlds

Industrialization of China increases fragility of global food supply

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