Enlarge / A diagram of the transistors built in this paper, next to a false-colored image of the actual hardware. Atomically thin materials like graphene and carbon nanotubes have the potential to provide significant benefits compared to today’s electronics, like smaller features, lower operating voltages, and more efficient performance. So, even though we’re struggling to figure out how to use them in bulk manufactured electronics, lots of organizations are spending money, brains, and time to work that out. Note the phrasing above—potential. Since it’s been incredibly hard to make transistors based on these materials, we aren’t entirely sure how all of them will behave. A group of researchers from China’s Peking University decided it was time to cut down on some of the uncertainty. The answer they came up with? Transistors made with carbon nanotubes and graphene perform so well that they’re pushing up against the fundamental limits set by Heisenberg’s uncertainty principle. That still doesn’t mean we can make a chip full of these things, but it does show it’s worth the continued effort to try to figure out how. Read 10 remaining paragraphs | Comments
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Carbon nanotube transistors push up against quantum uncertainty limits
An anonymous reader quotes a report from New Scientist: A female shark separated from her long-term mate has developed the ability to have babies on her own. Leonie the zebra shark (Stegostoma fasciatum) met her male partner at an aquarium in Townsville, Australia, in 1999. They had more than two dozen offspring together before he was moved to another tank in 2012. From then on, Leonie did not have any male contact. But in early 2016, she had three baby sharks. Intrigued, Christine Dudgeon at the University of Queensland in Brisbane, Australia, and her colleagues began fishing for answers. One possibility was that Leonie had been storing sperm from her ex and using it to fertilize her eggs. But genetic testing showed that the babies only carried DNA from their mum, indicating they had been conceived via asexual reproduction. Some vertebrate species have the ability to reproduce asexually even though they normally reproduce sexually. These include certain sharks, turkeys, Komodo dragons, snakes and rays. However, most reports have been in females who have never had male partners. In sharks, asexual reproduction can occur when a female’s egg is fertilized by an adjacent cell known as a polar body, Dudgeon says. This also contains the female’s genetic material, leading to “extreme inbreeding”, she says. “It’s not a strategy for surviving many generations because it reduces genetic diversity and adaptability.” Nevertheless, it may be necessary at times when males are scarce. “It might be a holding-on mechanism, ” Dudgeon says. “Mum’s genes get passed down from female to female until there are males available to mate with.” It’s possible that the switch from sexual to asexual reproduction is not that unusual; we just haven’t known to look for it, Dudgeon says. Read more of this story at Slashdot. 