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Research news and discovery
ENRIQUE DE LA OSA/EPA/CORBIS
In brief– Mighty migraines
It’s the little things that set hurricanes on their course WATER droplets and snowflakes may help steer the most powerful storms on the planet. To predict where hurricanes are headed, meteorologists usually feed measurements of large-scale influences such as sea temperature and air pressure into complex computer models. Now Robert Fovell of the University of California, Los Angeles, and Hui Su of the Jet Propulsion Laboratory in Pasadena suggest they may be missing a trick. Modelling rain and ice inside clouds may help predict a hurricane’s path more precisely, they say (Geophysical Research Letters, DOI: 10.1029/2007GL031723). The researchers took a computer model based on
hurricane Rita in 2005, and ran it several times, varying the way in which water vapour condensed to form ice and water droplets. When water was represented only by raindrops and cloud droplets, the storm drifted west across the Gulf of Mexico toward Houston. When ice crystals and snow were added to the mix, Rita slammed into the TexasLouisiana border, just as it did two years ago. The size of raindrops can also make a difference, Fovell says. The smaller they are, the more slowly they fall and the farther out they migrate. With more condensed water in the outer reaches, Fovell speculates the air pressure will increase as a result of the added density. This drives up the pressure gradient between the lowpressure eye and the outer reaches, which increases wind speed. Stronger counter-clockwise winds would drive the hurricane westwards, he says.
Nursing mice benefit from a haircut COOL mothers produce plumper babies – at least among mice. Feeding pups and producing milk is hard work, and generates so much waste heat that a mouse risks overheating. This constrains the amount of milk a mother can produce, says John Speakman at the University of Aberdeen, UK. When Speakman shaved the backs of nursing mice to allow them to lose more heat through www.newscientist.com
the skin, he found that milk production and the weight of the litter both increased by 15 per cent (The Journal of Experimental Biology, DOI: 10.1242/jeb.014266). Once shaved, females kept cooler and could afford to eat and nurse more. “If prevention of overheating is important for animals that need to keep a constant body temperature, like mammals and
birds, then this could for example explain why litter and clutch sizes are bigger in cooler regions,” says Speakman. He says biologists should consider how reproductive and feeding behaviours may be affected by global warming. So should human mothers strip off to increase milk production? Speakman knows women who have mentioned feeling flustered when nursing. “If that applies and the woman worries about milk supply, then cooling down a little may be worth trying,” he says.
IT IS becoming hard to dismiss migraines as simply very bad headaches. Earlier this year, Nouchine Hadjikhani of Harvard Medical School found that the fibres relaying pain signals from the head to the brain were thicker in migraine sufferers than in volunteers. She has now found that they also have a thicker somatosensory cortex – the brain area that processes sensation. Twelve migraine patients with aura, 12 without, and 12 volunteers had their brains scanned using MRI. This revealed that the part of the somatosensory cortex that processes sensations from the face and head was up to 21 per cent thicker in people with migraines than in volunteers (Neurology, DOI: 10.1212/01. wnl.0000291618.32247.2d ). Hadjikhani says it’s becoming increasing clear that migraines are symptomatic of progressive neurological disease.
Good week for a moonwalk GOOD news for lunar astronauts who fancy a stroll. Every month brings about seven straight days of relative safety from the flux of energetic charged particles from the sun, as the moon dips through the Earth’s magnetic field. Robert Winglee of the University of Washington, Seattle, calculated that some parts of the moon spend about a quarter of the moon’s orbit protected by Earth’s magnetosphere (Geophysical Research Letters, DOI: 10.1029/ 2007GL030507). “Very few megaelectronvolt particles would be able to reach an equatorial moon base while it’s shielded by the terrestrial magnetosphere,” he says. A solar storm would still pose a risk for wandering astronauts, he adds, but there would be time to return to a shielded base. 24 November 2007 | NewScientist | 19
ENRIQUE DE LA OSA/EPA/CORBIS
In brief– Mighty migraines
It’s the little things that set hurricanes on their course WATER droplets and snowflakes may help steer the most powerful storms on the planet. To predict where hurricanes are headed, meteorologists usually feed measurements of large-scale influences such as sea temperature and air pressure into complex computer models. Now Robert Fovell of the University of California, Los Angeles, and Hui Su of the Jet Propulsion Laboratory in Pasadena suggest they may be missing a trick. Modelling rain and ice inside clouds may help predict a hurricane’s path more precisely, they say (Geophysical Research Letters, DOI: 10.1029/2007GL031723). The researchers took a computer model based on
hurricane Rita in 2005, and ran it several times, varying the way in which water vapour condensed to form ice and water droplets. When water was represented only by raindrops and cloud droplets, the storm drifted west across the Gulf of Mexico toward Houston. When ice crystals and snow were added to the mix, Rita slammed into the TexasLouisiana border, just as it did two years ago. The size of raindrops can also make a difference, Fovell says. The smaller they are, the more slowly they fall and the farther out they migrate. With more condensed water in the outer reaches, Fovell speculates the air pressure will increase as a result of the added density. This drives up the pressure gradient between the lowpressure eye and the outer reaches, which increases wind speed. Stronger counter-clockwise winds would drive the hurricane westwards, he says.
Nursing mice benefit from a haircut COOL mothers produce plumper babies – at least among mice. Feeding pups and producing milk is hard work, and generates so much waste heat that a mouse risks overheating. This constrains the amount of milk a mother can produce, says John Speakman at the University of Aberdeen, UK. When Speakman shaved the backs of nursing mice to allow them to lose more heat through www.newscientist.com
the skin, he found that milk production and the weight of the litter both increased by 15 per cent (The Journal of Experimental Biology, DOI: 10.1242/jeb.014266). Once shaved, females kept cooler and could afford to eat and nurse more. “If prevention of overheating is important for animals that need to keep a constant body temperature, like mammals and
birds, then this could for example explain why litter and clutch sizes are bigger in cooler regions,” says Speakman. He says biologists should consider how reproductive and feeding behaviours may be affected by global warming. So should human mothers strip off to increase milk production? Speakman knows women who have mentioned feeling flustered when nursing. “If that applies and the woman worries about milk supply, then cooling down a little may be worth trying,” he says.
IT IS becoming hard to dismiss migraines as simply very bad headaches. Earlier this year, Nouchine Hadjikhani of Harvard Medical School found that the fibres relaying pain signals from the head to the brain were thicker in migraine sufferers than in volunteers. She has now found that they also have a thicker somatosensory cortex – the brain area that processes sensation. Twelve migraine patients with aura, 12 without, and 12 volunteers had their brains scanned using MRI. This revealed that the part of the somatosensory cortex that processes sensations from the face and head was up to 21 per cent thicker in people with migraines than in volunteers (Neurology, DOI: 10.1212/01. wnl.0000291618.32247.2d ). Hadjikhani says it’s becoming increasing clear that migraines are symptomatic of progressive neurological disease.
Good week for a moonwalk GOOD news for lunar astronauts who fancy a stroll. Every month brings about seven straight days of relative safety from the flux of energetic charged particles from the sun, as the moon dips through the Earth’s magnetic field. Robert Winglee of the University of Washington, Seattle, calculated that some parts of the moon spend about a quarter of the moon’s orbit protected by Earth’s magnetosphere (Geophysical Research Letters, DOI: 10.1029/ 2007GL030507). “Very few megaelectronvolt particles would be able to reach an equatorial moon base while it’s shielded by the terrestrial magnetosphere,” he says. A solar storm would still pose a risk for wandering astronauts, he adds, but there would be time to return to a shielded base. 24 November 2007 | NewScientist | 19