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Astrophile: Exoplanetary bedfellows make odd couple
IN BRIEF
Plainpicture
MEATY snacks: they’re not just for Venus flytraps. Almost any plant can be a carnivore with the help of fungi that kill insects and carry the nutrients into the plant’s roots. Most plants cannot take nitrogen directly out of the air or soil, so they rely on fungi and bacteria to capture it from, for instance, decaying organic matter in the soil. Among the most ubiquitous of these fungi are Metarhizium. The fungi release enzymes to eat through an insect’s shell, then slowly take over the host and kill it from the inside. A team led by Michael Bidochka of Brock University in St Catharines, Ontario, Canada, wondered whether the insect-killing and plant-feeding were linked. They injected labelled nitrogen into wax moth larvae (Galleria mellonella) and infected them with fungi. The team then buried the larvae in the soil with either beans or switchgrass plants. A screen with pores too small for plant roots to penetrate but large enough for the fungi to traverse separated the insects and the roots. After 14 days, the researchers found their labelled nitrogen in the plants’ tissues (Science, DOI: 10.1126/science.1222289). “It completes the circle,” says Raymond St Leger, an entomologist at the University of Maryland in College Park. Insects eat plants, but plants get their revenge eventually.
16 | NewScientist | 30 June 2012
Gut reactions reveal race is all in the mind TAKING pointers from rubber hands, psychologists have shown that racial differences really are only skin deep. When someone sees a rubber hand being stroked while their actual hand is hidden from view and stroked simultaneously, they can begin to “embody” it – to feel that the rubber hand is their own – and lose feeling in their real hand. But can you embody a rubber hand of a different skin colour from your own? Manos Tsakiris and colleagues at Royal Holloway, University of London, induced the
illusion in 22 white participants, using both white and black rubber hands. Later, the subjects claimed to have identified more strongly with the white hand. Objective measures suggested otherwise, though. For instance, the team tested changes in skin conductance – a measure of stress – when the subjects saw a needle being stuck into the embodied rubber hand. In theory, the more the subject identifies with the rubber hand, the greater this stress response. Yet they were just as stressed watching the
needle puncture the black hand as the white one (Consciousness and Cognition, DOI: 10.1016/ j.concog.2012.04.011). “The processes that are involved in the illusion aren’t particularly sensitive to the skin colour of the hand,” says team member Harry Farmer. “The way that the brain defines who we are doesn’t care that much about the surface features, it cares about actual sensory experiences,” says Patrick Haggard of University College London, who was not involved in the work. David Aguilar/Harvard-Smithsonian Center for Astrophysics
Killer fungi feed insects to plants
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Think of a word, any word… MIND-READERS are a step closer to divining the words we are thinking: they have eavesdropped on the brains of volunteers as they mentally rifled through their memories to retrieve words. Michael Kahana at the University of Pennsylvania in Philadelphia and his colleagues recruited 46 volunteers with epilepsy who had already had electrodes implanted in their brains for treatment purposes. The electrodes allowed the researchers to measure the brain’s activity as the participants viewed lists of 15 to 20 words. A minute later, they were asked to recall the words aloud, in any order. Subjects tended to recall words of similar meaning together. They also reproduced the same pattern of brain activity a second before saying the word as they did when they first viewed it in the list (Journal of Neuroscience, DOI: 10.1523/jneurosci.5321-11.2012). Kahana hopes to perform follow-up studies. He will look at the brain patterns associated with memories stored according to other criteria – for instance, how big objects were, what they smelled or tasted like, or where they were geographically.
Meet the exoplanetary odd couple A HOT Neptune and a super Earth are orbiting their star at almost the same distance. It’s baffling how two wildly different worlds got so close. Once, our only model for how a solar system is organised was our own: rocky planets in the inner circle, gas giants in the outer reaches. This neat picture was disrupted 25 years ago by glimpses of the first exoplanets – gas giants more massive than Jupiter, orbiting closer to their stars than Mercury. These “hot Jupiters” were loners, having trashed any planet siblings on their journey to the inner solar system.
Now our view has been broadened further. When Josh Carter of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and his team looked at data from the Kepler space telescope, they found a rocky planet with a radius 1.5 times greater than Earth’s, orbiting within a cosmic whisker of a gassy planet with a radius 2.5 times larger still. The pair are 20 times closer than Earth and Venus (Science, DOI: 10.1126/ science.1223269). Either the pair formed near these orbits or the larger moved in without trashing the other.
Plainpicture
MEATY snacks: they’re not just for Venus flytraps. Almost any plant can be a carnivore with the help of fungi that kill insects and carry the nutrients into the plant’s roots. Most plants cannot take nitrogen directly out of the air or soil, so they rely on fungi and bacteria to capture it from, for instance, decaying organic matter in the soil. Among the most ubiquitous of these fungi are Metarhizium. The fungi release enzymes to eat through an insect’s shell, then slowly take over the host and kill it from the inside. A team led by Michael Bidochka of Brock University in St Catharines, Ontario, Canada, wondered whether the insect-killing and plant-feeding were linked. They injected labelled nitrogen into wax moth larvae (Galleria mellonella) and infected them with fungi. The team then buried the larvae in the soil with either beans or switchgrass plants. A screen with pores too small for plant roots to penetrate but large enough for the fungi to traverse separated the insects and the roots. After 14 days, the researchers found their labelled nitrogen in the plants’ tissues (Science, DOI: 10.1126/science.1222289). “It completes the circle,” says Raymond St Leger, an entomologist at the University of Maryland in College Park. Insects eat plants, but plants get their revenge eventually.
16 | NewScientist | 30 June 2012
Gut reactions reveal race is all in the mind TAKING pointers from rubber hands, psychologists have shown that racial differences really are only skin deep. When someone sees a rubber hand being stroked while their actual hand is hidden from view and stroked simultaneously, they can begin to “embody” it – to feel that the rubber hand is their own – and lose feeling in their real hand. But can you embody a rubber hand of a different skin colour from your own? Manos Tsakiris and colleagues at Royal Holloway, University of London, induced the
illusion in 22 white participants, using both white and black rubber hands. Later, the subjects claimed to have identified more strongly with the white hand. Objective measures suggested otherwise, though. For instance, the team tested changes in skin conductance – a measure of stress – when the subjects saw a needle being stuck into the embodied rubber hand. In theory, the more the subject identifies with the rubber hand, the greater this stress response. Yet they were just as stressed watching the
needle puncture the black hand as the white one (Consciousness and Cognition, DOI: 10.1016/ j.concog.2012.04.011). “The processes that are involved in the illusion aren’t particularly sensitive to the skin colour of the hand,” says team member Harry Farmer. “The way that the brain defines who we are doesn’t care that much about the surface features, it cares about actual sensory experiences,” says Patrick Haggard of University College London, who was not involved in the work. David Aguilar/Harvard-Smithsonian Center for Astrophysics
Killer fungi feed insects to plants
For new stories every day, visit newscientist.com/news
Think of a word, any word… MIND-READERS are a step closer to divining the words we are thinking: they have eavesdropped on the brains of volunteers as they mentally rifled through their memories to retrieve words. Michael Kahana at the University of Pennsylvania in Philadelphia and his colleagues recruited 46 volunteers with epilepsy who had already had electrodes implanted in their brains for treatment purposes. The electrodes allowed the researchers to measure the brain’s activity as the participants viewed lists of 15 to 20 words. A minute later, they were asked to recall the words aloud, in any order. Subjects tended to recall words of similar meaning together. They also reproduced the same pattern of brain activity a second before saying the word as they did when they first viewed it in the list (Journal of Neuroscience, DOI: 10.1523/jneurosci.5321-11.2012). Kahana hopes to perform follow-up studies. He will look at the brain patterns associated with memories stored according to other criteria – for instance, how big objects were, what they smelled or tasted like, or where they were geographically.
Meet the exoplanetary odd couple A HOT Neptune and a super Earth are orbiting their star at almost the same distance. It’s baffling how two wildly different worlds got so close. Once, our only model for how a solar system is organised was our own: rocky planets in the inner circle, gas giants in the outer reaches. This neat picture was disrupted 25 years ago by glimpses of the first exoplanets – gas giants more massive than Jupiter, orbiting closer to their stars than Mercury. These “hot Jupiters” were loners, having trashed any planet siblings on their journey to the inner solar system.
Now our view has been broadened further. When Josh Carter of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, and his team looked at data from the Kepler space telescope, they found a rocky planet with a radius 1.5 times greater than Earth’s, orbiting within a cosmic whisker of a gassy planet with a radius 2.5 times larger still. The pair are 20 times closer than Earth and Venus (Science, DOI: 10.1126/ science.1223269). Either the pair formed near these orbits or the larger moved in without trashing the other.