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9 October 2010 | NewScientist | 17 Apples’ abs have big bad fat cells AS MANY women will no doubt attest, not all fat accrues equally. That may be because cells in your thighs and abdomen store fat in different ways. Michael Jensen and colleagues at the Mayo Clinic in Rochester, Minnesota, put volunteers on a fattening diet for eight weeks and then measured what happened to their fat cells, or adipocytes. While abdominal cells got larger, thigh cells multiplied, by recruiting more adipocytes from pre-fat cells. The more new thigh fat cells recruited, the less abdominal fat people gained (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1005259107). Fat on the abdomen increases the risk of diabetes and other disorders, while fat on hips and thighs has a protective effect. Jensen thinks thigh fat may soak up excess food energy to keep it away from the abdomen, where fat does more damage. An individual’s tendency to be pear or apple-shaped may in part be set by the ability of their thigh fat cells to recruit more adipocytes. Learning what controls this process may help fight fat’s detrimental effects on our health. Quantum thermometers usher in the big chill IN THE quantum world, simply measuring temperature can cool things down. Quantum systems normally exist in a superposition of several states at once, but collapse into a single state when observed. Two years ago physicists came up with the prediction that gauging the temperature of quantum objects could cause this collapse to occur in a way that cooled the object. Now Gonzalo Álvarez of the National University of Córdoba in Argentina and his colleagues have put this prediction to the test. The team looked at the alignment of the spins of carbon and hydrogen nuclei in molecules of methyl iodide. Temperature is a measure of disorder: the higher the temperature, the more disordered a system is. So a fall in the temperature of the spins equates to them becoming more ordered, increasingly aligning with each other, instead of pointing any which way. The nuclei normally play “catch” with each other, tossing energy back and forth, so that the spins of the carbon nuclei get PENGUINS donned their black-and- white suits late in their evolution – and may have become faster swimmers when they did. The finding comes from inspection of a 36-million-year-old fossil discovered in Peru and dubbed Inkayacu paracasensis. At 1.5 metres tall and weighing 55 to 60 kilograms, it is among the largest specimens in the penguin lineage. The fossil is built very much like a modern penguin, but when Julia Clarke of the University of Texas, Austin, inspected the melanin-rich grains called melanosomes on its feathers, she found a surprising difference. The shape and size of the grains give feathers their colour, and Inkayacu’s suggest it had a grey back and reddish-brown front (Science, DOI: 10.1126/science.1193604). The colour change may have given the ancient birds a turbo boost, Clarke speculates. She thinks the shape, large size and grape-like clustering of their melanosomes may have affected how their feathers were packed and helped to streamline them, giving the birds a slight edge when seals – a major predator of penguins – evolved some 20 million years ago. Speedy swimsuit for modern penguins NORBERT WU/MINDEN/GETTY alternately cooler and warmer. Álvarez’s team couldn’t make spin measurements directly, but used brief magnetic pulses to create an effect similar to measuring the orderliness of the spins. They found that when these pulses were repeated about once per millisecond, the temperature fell. The pulses stop the game of catch just after the carbon spins toss away their energy, so every time the game is interrupted, the spins cool down further. The work will be published in Physical Review Letters. Black widow is fattest dead star A CANNIBALISTIC collapsed star is growing so fat from the partner it is slowly devouring that it is likely to be the most massive neutron star yet measured. The observation suggests that neutron stars can grow much bigger than previously thought before collapsing to become a black hole. The star in question is a “black widow” pulsar, a type of rotating neutron star that is highly magnetised. It rotates in tandem with a smaller partner, which its gravitational field slowly destroys. Previously the most massive neutron star known was between 1.66 and 1.68 times as massive as the sun. Now Marten van Kerkwijk of the University of Toronto, Canada, and his colleagues estimate that the black widow pulsar B1957+20 (depicted below) is 2.4 solar masses (arxiv.org/ abs/1009.5427). This rules out the popular “Brown-Bethe” model, which says the maximum mass for a neutron star is about 1.5 solar masses before collapse into a black hole is inevitable, as well as other models. “Two solar masses would exclude a whole bunch of models and 2.4 solar masses would blow just about anything away,” says co-author Shrinivas Kulkarni of the California Institute of Technology in Pasadena. NASA/CXC/M.WEISS For new stories every day, visit www.NewScientist.com/news

Cells in your thighs and abdomen store fat unequally

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9 October 2010 | NewScientist | 17

Apples’ abs have big bad fat cells

AS MANY women will no doubt attest, not all fat accrues equally. That may be because cells in your thighs and abdomen store fat in different ways.

Michael Jensen and colleagues at the Mayo Clinic in Rochester, Minnesota, put volunteers on a fattening diet for eight weeks and then measured what happened to their fat cells, or adipocytes. While abdominal cells got larger, thigh cells multiplied, by recruiting more adipocytes from pre-fat cells. The more new thigh fat cells recruited, the less abdominal fat people gained (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.1005259107).

Fat on the abdomen increases the risk of diabetes and other disorders, while fat on hips and thighs has a protective effect. Jensen thinks thigh fat may soak up excess food energy to keep it away from the abdomen, where fat does more damage.

An individual’s tendency to be pear or apple-shaped may in part be set by the ability of their thigh fat cells to recruit more adipocytes. Learning what controls this process may help fight fat’s detrimental effects on our health.

Quantum thermometers usher in the big chillIN THE quantum world, simply measuring temperature can cool things down.

Quantum systems normally exist in a superposition of several states at once, but collapse into a single state when observed. Two years ago physicists came up with the prediction that gauging the temperature of quantum objects could cause this collapse to occur in a way that cooled the object. Now Gonzalo Álvarez of the National University of Córdoba in Argentina and his colleagues have put this prediction to the test.

The team looked at the alignment of the spins of carbon and hydrogen nuclei in molecules of methyl iodide. Temperature is a measure of disorder: the higher the temperature, the more disordered a system is. So a fall in the temperature of the spins equates to them becoming more ordered, increasingly aligning with each other, instead of pointing any which way.

The nuclei normally play “catch” with each other, tossing energy back and forth, so that the spins of the carbon nuclei get

PENGUINS donned their black-and-white suits late in their evolution – and may have become faster swimmers when they did.

The finding comes from inspection of a 36-million-year-old fossil discovered in Peru and dubbed Inkayacu paracasensis. At 1.5 metres tall and weighing 55 to 60 kilograms, it is among the largest specimens in the penguin lineage.

The fossil is built very much like a modern penguin, but when Julia Clarke of the University of Texas, Austin, inspected the melanin-rich grains called melanosomes on its

feathers, she found a surprising difference. The shape and size of the grains give feathers their colour, and Inkayacu ’s suggest it had a grey back and reddish-brown front (Science, DOI: 10.1126/science.1193604).

The colour change may have given the ancient birds a turbo boost, Clarke speculates. She thinks the shape, large size and grape-like clustering of their melanosomes may have affected how their feathers were packed and helped to streamline them, giving the birds a slight edge when seals – a major predator of penguins – evolved some 20 million years ago.

Speedy swimsuit for modern penguins

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alternately cooler and warmer. Álvarez’s team couldn’t make spin measurements directly, but used brief magnetic pulses to create an effect similar to measuring the orderliness of the spins. They found that when these pulses were repeated about once per millisecond, the temperature fell.

The pulses stop the game of catch just after the carbon spins toss away their energy, so every time the game is interrupted, the spins cool down further. The work will be published in Physical Review Letters.

Black widow is fattest dead star

A CANNIBALISTIC collapsed star is growing so fat from the partner it is slowly devouring that it is likely to be the most massive neutron star yet measured. The observation suggests that neutron stars can grow much bigger than previously thought before collapsing to become a black hole.

The star in question is a “black widow” pulsar, a type of rotating neutron star that is highly magnetised. It rotates in tandem with a smaller partner, which its gravitational field slowly destroys.

Previously the most massive neutron star known was between 1.66 and 1.68 times as massive as the sun. Now Marten van Kerkwijk of the University of Toronto, Canada, and his colleagues estimate that the black widow pulsar B1957+20 (depicted below) is 2.4 solar masses (arxiv.org/abs/1009.5427).

This rules out the popular “Brown-Bethe” model, which says the maximum mass for a neutron star is about 1.5 solar masses before collapse into a black hole is inevitable, as well as other models.

“Two solar masses would exclude a whole bunch of models and 2.4 solar masses would blow just about anything away,” says co-author Shrinivas Kulkarni of the California Institute of Technology in Pasadena.

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For new stories every day, visit www.NewScientist.com/news

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