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Local clot-buster has less bleed risk
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in Brief Local clot-buster has less bleed risk
Little chance of a good night’s sleep in space DRIFTING in space is easy, but not so drifting off to sleep. Astronauts have been complaining of sleep deficiency since the beginning of human space flight, and managing sleep will become even more important as space agencies prepare for longer journeys. “Trying to sleep in space is a neat kind of disorientation,” says six-time NASA astronaut Story Musgrave. “There’s no clock, no day or night, no up or down.” In the most comprehensive astronaut sleep study to date, Laura Barger of Harvard Medical School in Boston and her colleagues monitored 64 astronauts over
a total of 4200 “nights” in space and 4000 on Earth, using diaries and wrist devices that record sleep. The average astronaut slept about 2 hours less than the 8.5 hours they are normally allotted. What’s more, sleep deficiency can build up in astronauts from as early as three months before lift-off, possibly as a result of rigorous training and preparations (The Lancet Neurology, doi.org/t37). More than 75 per cent of astronauts resort to sleep medication at some point to cope, but Barger warns that this strategy could backfire in an emergency. Future research will explore the use of short-wavelength light to boost alertness, behavioural changes and schedule modifications that might help astronauts get all the shuteye they need.
Lumpy little asteroids pose extra threat SMALL asteroids made of collections of rock could be extra dangerous. They are held together by very weak forces, so any attempt to push them off a collision course with Earth might make them crumble into multiple, equally dangerous chunks. Some asteroids are loose piles of rubble, rather than a single dense rock. Calculations suggest that gravity can only hold such asteroids together if they spin no faster than once every 14 | NewScientist | 16 August 2014
2.2 hours. But a few objects break this speed limit. Ben Rozitis at the University of Tennessee in Knoxville and his colleagues think they have an explanation for these outlaws. The team studied the 1.1-kilometre-wide asteroid (29075) 1950 DA, which has a very low chance of hitting Earth in 2880. Past radar observations showed the asteroid is highly reflective, which suggested it was made of metal. But Rozitis and
colleagues found its density was much lower than expected, meaning it must be a rubble pile. Yet the asteroid spins once every 2.1 hours, and is too small for gravity to hold it together. Instead, the team says, static-like van der Waals forces help it stick. The force is also responsible for flour caking (Nature, DOI: 10.1038/ nature13632). Any plans to deflect an asteroid headed for Earth will need to take this into account, since a successful strike risks making matters worse.
A NEW drug treats blood clots without boosting bleeding risk. Clots form when blood platelets clump together. They are treated with blood-thinning drugs, but these must be given orally as they need to be metabolised by the liver to work. This means they disperse throughout the body, which risks triggering bleeding elsewhere. Douglas Moeckel at the Washington University School of Medicine in St Louis has now developed a more targeted drug using an enzyme that regulates platelet aggregation. He altered its structure to make it more potent. Enzymes work immediately, so the drug can be injected near a blood clot for a localised effect. When tested on dogs with clots in their hearts, the altered enzyme reduced the clot size by 81 per cent without increasing the time it took for a wound on their lips to stop bleeding (Science Translational Medicine, doi.org/t4f).
Pacific dead zone shrank for decades OCEAN “dead zones” are growing around the world, but a big one shrank for most of last century. Freak conditions may be at work, but it offers hope that parts of the ocean will remain breathable. Dead zones form when plankton die and get eaten by bacteria – a process that uses up much of the available oxygen. Most such zones are growing, partly due to global warming. But not the one in the eastern Pacific, says Curtis Deutsch at the University of Washington in Seattle. His team reconstructed changes in oxygen levels since 1850 using sediments that carry traces of past oxygen levels. They found that the Pacific dead zone has been shrinking for nearly all that time (Science, doi.org/t4c).
in Brief Local clot-buster has less bleed risk
Little chance of a good night’s sleep in space DRIFTING in space is easy, but not so drifting off to sleep. Astronauts have been complaining of sleep deficiency since the beginning of human space flight, and managing sleep will become even more important as space agencies prepare for longer journeys. “Trying to sleep in space is a neat kind of disorientation,” says six-time NASA astronaut Story Musgrave. “There’s no clock, no day or night, no up or down.” In the most comprehensive astronaut sleep study to date, Laura Barger of Harvard Medical School in Boston and her colleagues monitored 64 astronauts over
a total of 4200 “nights” in space and 4000 on Earth, using diaries and wrist devices that record sleep. The average astronaut slept about 2 hours less than the 8.5 hours they are normally allotted. What’s more, sleep deficiency can build up in astronauts from as early as three months before lift-off, possibly as a result of rigorous training and preparations (The Lancet Neurology, doi.org/t37). More than 75 per cent of astronauts resort to sleep medication at some point to cope, but Barger warns that this strategy could backfire in an emergency. Future research will explore the use of short-wavelength light to boost alertness, behavioural changes and schedule modifications that might help astronauts get all the shuteye they need.
Lumpy little asteroids pose extra threat SMALL asteroids made of collections of rock could be extra dangerous. They are held together by very weak forces, so any attempt to push them off a collision course with Earth might make them crumble into multiple, equally dangerous chunks. Some asteroids are loose piles of rubble, rather than a single dense rock. Calculations suggest that gravity can only hold such asteroids together if they spin no faster than once every 14 | NewScientist | 16 August 2014
2.2 hours. But a few objects break this speed limit. Ben Rozitis at the University of Tennessee in Knoxville and his colleagues think they have an explanation for these outlaws. The team studied the 1.1-kilometre-wide asteroid (29075) 1950 DA, which has a very low chance of hitting Earth in 2880. Past radar observations showed the asteroid is highly reflective, which suggested it was made of metal. But Rozitis and
colleagues found its density was much lower than expected, meaning it must be a rubble pile. Yet the asteroid spins once every 2.1 hours, and is too small for gravity to hold it together. Instead, the team says, static-like van der Waals forces help it stick. The force is also responsible for flour caking (Nature, DOI: 10.1038/ nature13632). Any plans to deflect an asteroid headed for Earth will need to take this into account, since a successful strike risks making matters worse.
A NEW drug treats blood clots without boosting bleeding risk. Clots form when blood platelets clump together. They are treated with blood-thinning drugs, but these must be given orally as they need to be metabolised by the liver to work. This means they disperse throughout the body, which risks triggering bleeding elsewhere. Douglas Moeckel at the Washington University School of Medicine in St Louis has now developed a more targeted drug using an enzyme that regulates platelet aggregation. He altered its structure to make it more potent. Enzymes work immediately, so the drug can be injected near a blood clot for a localised effect. When tested on dogs with clots in their hearts, the altered enzyme reduced the clot size by 81 per cent without increasing the time it took for a wound on their lips to stop bleeding (Science Translational Medicine, doi.org/t4f).
Pacific dead zone shrank for decades OCEAN “dead zones” are growing around the world, but a big one shrank for most of last century. Freak conditions may be at work, but it offers hope that parts of the ocean will remain breathable. Dead zones form when plankton die and get eaten by bacteria – a process that uses up much of the available oxygen. Most such zones are growing, partly due to global warming. But not the one in the eastern Pacific, says Curtis Deutsch at the University of Washington in Seattle. His team reconstructed changes in oxygen levels since 1850 using sediments that carry traces of past oxygen levels. They found that the Pacific dead zone has been shrinking for nearly all that time (Science, doi.org/t4c).