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Acoustic graphene could act as a sonic cloak
Peter Hendrie/Lonely Planet Images
IN BRIEF Forget carving silicon and crack it
Blonde hair – so good we evolved it (at least) twice SCIENCE can’t yet tell us if they have more fun – but it has uncovered a new genetic change that makes people blonde. Contrary to long-held belief, it seems golden hair evolved separately in different human populations. Indigenous people of the Solomon Islands in the south Pacific Ocean have some of the darkest skin pigmentation outside of Africa. But unlike most tropical peoples, about 10 per cent also have blonde hair, the highest proportion outside of Europe. Until now, this trait was attributed to the influence of European explorers. “We originally thought, well that must be a ‘Captain Cook allele’,” says
Carlos Bustamante of Stanford University in California. Yet after analysing saliva from 43 blonde and 42 dark-haired Solomon Islanders, Bustamante and colleagues found that a difference in a gene called TYRP1 accounted for 46 per cent of variation of the population’s hair colour, with the blonde variant, or allele, being recessive to the dark-hair allele. The blonde mutation was not found in 900 people sampled from beyond the south Pacific region (Science, DOI: 10.1126/science.1217849). TYRP1 is involved in pigmentation in several species, but is not one of the genes that produces blonde hair in Europeans. The blonde mutation in Solomon Islanders likely emerged about 10,000 years ago. “This tells us we can’t assume that even common mutations are common across different human populations,” says Bustamante.
Simile is like a metaphor, or not ARISTOTLE concluded in the 4th century BC that “the difference is but slight” between similes and metaphors. After all, the metaphor “he’s a bear in the morning” means the same as the simile “he’s like a bear in the morning”. Our brains, apparently, do not agree. Midori Shibata and colleagues at Hokkaido University in Sapporo, Japan, asked 24 men and women to indicate, while in a 16 | NewScientist | 12 May 2012
functional MRI scanner, whether they could understand a series of metaphors or similes. In keeping with previous fMRI research, participants’ brains were active in the left inferior frontal gyrus. But Shibata’s team also found that there was an increase in activity in the medial frontal region when processing similes, which may be linked to processes of
inference. The right inferior frontal gyrus (IFG) was more active for metaphors (Brain and Language, DOI: 10.1016/ j.bandl.2012.03.006). Shibata says the findings build on research suggesting that “the right IFG has a complementary role in language comprehension”. The team next hopes to use EEG to put these figurative constructions under the microscope – metaphorically speaking, of course.
SOMETIMES you need to break things to fix them. South Korean researchers have developed a way of controlling patterns of cracks in silicon chips to create atomic-scale features such as nano-channels. Koo Hyun Nam of Ewha Womans University in Seoul and colleagues etched a pattern of notches into a silicon wafer and deposited a layer of silicon nitride on top. The notches set up stresses within the nitride layer that cause it to crack in line with the underlying wafer’s crystal structure, which acts as a guide (Nature, DOI: 10.1038/ nature11002). Nam says the nano-cracks could serve as channels for lab-on-achip type applications such as single-molecule sensing. Electron beams are currently used to etch atomic-scale patterns, but this is time-consuming and expensive. By contrast, cracks form instantaneously, says Nam.
Acoustic ‘graphene’ could be sonic cloak THE amazing properties of graphene – a sheet of carbon with atoms in a hexagonal formation – have inspired something similar in the world of sound. By drilling holes in a hexagonal pattern in a sheet of perspex, researchers in Spain have created what they have dubbed “sonic graphene”. The holes act like an array of organ pipes that trap the sound as it moves across the surface. José Sánchez-Dehesa and Daniel Torrent at the Polytechnic University of Valencia claim that the sound moves in the same way as electrons in graphene, with almost no losses (Physical Review Letters, DOI: 10.1103/PhysRevLett. 108.174301). The material could guide sound around objects, acting as a sonic cloaking device.
IN BRIEF Forget carving silicon and crack it
Blonde hair – so good we evolved it (at least) twice SCIENCE can’t yet tell us if they have more fun – but it has uncovered a new genetic change that makes people blonde. Contrary to long-held belief, it seems golden hair evolved separately in different human populations. Indigenous people of the Solomon Islands in the south Pacific Ocean have some of the darkest skin pigmentation outside of Africa. But unlike most tropical peoples, about 10 per cent also have blonde hair, the highest proportion outside of Europe. Until now, this trait was attributed to the influence of European explorers. “We originally thought, well that must be a ‘Captain Cook allele’,” says
Carlos Bustamante of Stanford University in California. Yet after analysing saliva from 43 blonde and 42 dark-haired Solomon Islanders, Bustamante and colleagues found that a difference in a gene called TYRP1 accounted for 46 per cent of variation of the population’s hair colour, with the blonde variant, or allele, being recessive to the dark-hair allele. The blonde mutation was not found in 900 people sampled from beyond the south Pacific region (Science, DOI: 10.1126/science.1217849). TYRP1 is involved in pigmentation in several species, but is not one of the genes that produces blonde hair in Europeans. The blonde mutation in Solomon Islanders likely emerged about 10,000 years ago. “This tells us we can’t assume that even common mutations are common across different human populations,” says Bustamante.
Simile is like a metaphor, or not ARISTOTLE concluded in the 4th century BC that “the difference is but slight” between similes and metaphors. After all, the metaphor “he’s a bear in the morning” means the same as the simile “he’s like a bear in the morning”. Our brains, apparently, do not agree. Midori Shibata and colleagues at Hokkaido University in Sapporo, Japan, asked 24 men and women to indicate, while in a 16 | NewScientist | 12 May 2012
functional MRI scanner, whether they could understand a series of metaphors or similes. In keeping with previous fMRI research, participants’ brains were active in the left inferior frontal gyrus. But Shibata’s team also found that there was an increase in activity in the medial frontal region when processing similes, which may be linked to processes of
inference. The right inferior frontal gyrus (IFG) was more active for metaphors (Brain and Language, DOI: 10.1016/ j.bandl.2012.03.006). Shibata says the findings build on research suggesting that “the right IFG has a complementary role in language comprehension”. The team next hopes to use EEG to put these figurative constructions under the microscope – metaphorically speaking, of course.
SOMETIMES you need to break things to fix them. South Korean researchers have developed a way of controlling patterns of cracks in silicon chips to create atomic-scale features such as nano-channels. Koo Hyun Nam of Ewha Womans University in Seoul and colleagues etched a pattern of notches into a silicon wafer and deposited a layer of silicon nitride on top. The notches set up stresses within the nitride layer that cause it to crack in line with the underlying wafer’s crystal structure, which acts as a guide (Nature, DOI: 10.1038/ nature11002). Nam says the nano-cracks could serve as channels for lab-on-achip type applications such as single-molecule sensing. Electron beams are currently used to etch atomic-scale patterns, but this is time-consuming and expensive. By contrast, cracks form instantaneously, says Nam.
Acoustic ‘graphene’ could be sonic cloak THE amazing properties of graphene – a sheet of carbon with atoms in a hexagonal formation – have inspired something similar in the world of sound. By drilling holes in a hexagonal pattern in a sheet of perspex, researchers in Spain have created what they have dubbed “sonic graphene”. The holes act like an array of organ pipes that trap the sound as it moves across the surface. José Sánchez-Dehesa and Daniel Torrent at the Polytechnic University of Valencia claim that the sound moves in the same way as electrons in graphene, with almost no losses (Physical Review Letters, DOI: 10.1103/PhysRevLett. 108.174301). The material could guide sound around objects, acting as a sonic cloaking device.