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The most surreal sunset in the universe
IN BRIEF
Leland Bobbe/getty
TETCHY people might calm down if they had more of the neurotransmitter serotonin. Researchers gave 19 healthy volunteers a diet that reduced their serotonin levels and then scanned their brains. They found that communication between the brain’s amygdala regions, which process fear, and its restraining prefrontal cortex had broken down. That schism could unleash disproportionately violent reactions to mild threats. The team discovered the effect by showing the serotonin-poor volunteers pictures of angry, sad or neutral faces as they were having functional MRI brain scans. The volunteers were asked to say whether each image was of a man or a woman, but the real intention was to see how their brains reacted to the threat posed by angry faces. The scans showed that in all volunteers, the connectivity between the amygdalas and the prefrontal cortex was reduced when they viewed angry faces (Biological Psychiatry, DOI: 10.1016/j. biopsych.2011.07.033). The effect was strongest in those with violent tendencies, as identified in a questionnaire. “It’s as if the intervening voice of reason was lost,” says Luca Passamonti, head of the team at Italy’s Neuroimaging Research Unit in Catanzaro.
22 | NewScientist | 24 September 2011
Electron ping-pong plays well for quantum computing A SINGLE electron bouncing between two electrical traps has shown for the first time how information could be transferred between different parts of a quantum circuit. This game of quantum tennis marks an important step towards practical quantum computers. “We’re basically playing ping-pong with a single electron,” says Crispin Barnes at the University of Cambridge. “We can capture single electrons and move them backwards and forwards wherever we like.”
Quantum computers can perform hugely powerful calculations by manipulating information in the form of quantum bits, or qubits, which can be both a 0 and a 1 at the same time. Qubits are fragile, however, and the act of measurement destroys them. So to protect quantum calculations, researchers need a way to transfer qubits from the area where the number crunching happens to a separate spot where they can be measured in isolation. In a proof of concept
experiment, Barnes and his colleagues have done just that. The team created two electron traps called quantum dots on a slab of gallium arsenide. They then used microwave pulses to send a single electron back and forth between the dots. This shuttled the electron 60 times over a total distance of 0.25 millimetres (Nature, DOI: 10.1038/nature10444). This represents a real milestone, Barnes says. “The more bounces we get, the more amazing our quantum computer can be.” absolute film
Voice of reason needs serotonin
For new stories every day, visit newscientist.com/news
Tumours glow green for surgeons TRYING to remove every last cancer cell during surgery can be a bit like playing blind man’s buff: they are often the same colour as healthy cells, so surgeons risk leaving behind cancer cells which can regrow. But that could change thanks to a technique that makes ovarian cancer cells glow. Currently, surgeons largely rely on touch to determine where an ovarian tumour starts and ends. “You have no real clue where the borders are,” says Gooitzen Van Dam of the University of Groningen in the Netherlands. Van Dam and his colleagues took advantage of the fact that the vast majority of ovarian cancer cells over-express a receptor for folate on their cell surface while normal cells do not. They attached a fluorescent label to folate molecules and administered them to women via an intravenous drip 2 hours before surgery to remove their tumours. The labelled folate was taken up by the cancer cells but not normal cells, so surgeons could use a camera that detects fluorescence to see the tumours (Nature Medicine, DOI: 10.1038/nm.2472). They now plan to see if the method boosts patient survival rates.
Sunsets more surreal than fiction A PAIR of suns setting in tandem sounds surreal. But that’s exactly what you would see if you visited the newly discovered planet Kepler 16b, 200 light years from Earth. There, an orange star and a smaller red one orbit each other. NASA’s Kepler space telescope saw tiny dips in their brightnesses due to a planet passing in front of them, reports a team led by Laurance Doyle of the SETI Institute in Mountain View, California. It is the first planet confirmed to orbit two stars. Kepler 16b has been nicknamed Tatooine after the fictional planet in
Star Wars (see photo). Previous hints of planets orbiting binary stars have come from variations in the times when the stars eclipse each other, without confirmation from planet transits. Alien solar systems in which a planet orbits only one of several stars have also been found. The suns in Kepler 16b’s sky are more exciting than Tatooine’s: they are different sizes, brightnesses and colours, and seen from the planet the distance between them would constantly change, with regular eclipses. “No two sunsets would be the same,” says Doyle.
Leland Bobbe/getty
TETCHY people might calm down if they had more of the neurotransmitter serotonin. Researchers gave 19 healthy volunteers a diet that reduced their serotonin levels and then scanned their brains. They found that communication between the brain’s amygdala regions, which process fear, and its restraining prefrontal cortex had broken down. That schism could unleash disproportionately violent reactions to mild threats. The team discovered the effect by showing the serotonin-poor volunteers pictures of angry, sad or neutral faces as they were having functional MRI brain scans. The volunteers were asked to say whether each image was of a man or a woman, but the real intention was to see how their brains reacted to the threat posed by angry faces. The scans showed that in all volunteers, the connectivity between the amygdalas and the prefrontal cortex was reduced when they viewed angry faces (Biological Psychiatry, DOI: 10.1016/j. biopsych.2011.07.033). The effect was strongest in those with violent tendencies, as identified in a questionnaire. “It’s as if the intervening voice of reason was lost,” says Luca Passamonti, head of the team at Italy’s Neuroimaging Research Unit in Catanzaro.
22 | NewScientist | 24 September 2011
Electron ping-pong plays well for quantum computing A SINGLE electron bouncing between two electrical traps has shown for the first time how information could be transferred between different parts of a quantum circuit. This game of quantum tennis marks an important step towards practical quantum computers. “We’re basically playing ping-pong with a single electron,” says Crispin Barnes at the University of Cambridge. “We can capture single electrons and move them backwards and forwards wherever we like.”
Quantum computers can perform hugely powerful calculations by manipulating information in the form of quantum bits, or qubits, which can be both a 0 and a 1 at the same time. Qubits are fragile, however, and the act of measurement destroys them. So to protect quantum calculations, researchers need a way to transfer qubits from the area where the number crunching happens to a separate spot where they can be measured in isolation. In a proof of concept
experiment, Barnes and his colleagues have done just that. The team created two electron traps called quantum dots on a slab of gallium arsenide. They then used microwave pulses to send a single electron back and forth between the dots. This shuttled the electron 60 times over a total distance of 0.25 millimetres (Nature, DOI: 10.1038/nature10444). This represents a real milestone, Barnes says. “The more bounces we get, the more amazing our quantum computer can be.” absolute film
Voice of reason needs serotonin
For new stories every day, visit newscientist.com/news
Tumours glow green for surgeons TRYING to remove every last cancer cell during surgery can be a bit like playing blind man’s buff: they are often the same colour as healthy cells, so surgeons risk leaving behind cancer cells which can regrow. But that could change thanks to a technique that makes ovarian cancer cells glow. Currently, surgeons largely rely on touch to determine where an ovarian tumour starts and ends. “You have no real clue where the borders are,” says Gooitzen Van Dam of the University of Groningen in the Netherlands. Van Dam and his colleagues took advantage of the fact that the vast majority of ovarian cancer cells over-express a receptor for folate on their cell surface while normal cells do not. They attached a fluorescent label to folate molecules and administered them to women via an intravenous drip 2 hours before surgery to remove their tumours. The labelled folate was taken up by the cancer cells but not normal cells, so surgeons could use a camera that detects fluorescence to see the tumours (Nature Medicine, DOI: 10.1038/nm.2472). They now plan to see if the method boosts patient survival rates.
Sunsets more surreal than fiction A PAIR of suns setting in tandem sounds surreal. But that’s exactly what you would see if you visited the newly discovered planet Kepler 16b, 200 light years from Earth. There, an orange star and a smaller red one orbit each other. NASA’s Kepler space telescope saw tiny dips in their brightnesses due to a planet passing in front of them, reports a team led by Laurance Doyle of the SETI Institute in Mountain View, California. It is the first planet confirmed to orbit two stars. Kepler 16b has been nicknamed Tatooine after the fictional planet in
Star Wars (see photo). Previous hints of planets orbiting binary stars have come from variations in the times when the stars eclipse each other, without confirmation from planet transits. Alien solar systems in which a planet orbits only one of several stars have also been found. The suns in Kepler 16b’s sky are more exciting than Tatooine’s: they are different sizes, brightnesses and colours, and seen from the planet the distance between them would constantly change, with regular eclipses. “No two sunsets would be the same,” says Doyle.