An optical lattice clock with accuracy and stability at the 10-18 level : Nature : Natu... - 0 views
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Progress in atomic, optical and quantum science1, 2 has led to rapid improvements in atomic clocks. At the same time, atomic clock research has helped to advance the frontiers of science, affecting both fundamental and applied research. The ability to control quantum states of individual atoms and photons is central to quantum information science and precision measurement, and optical clocks based on single ions have achieved the lowest systematic uncertainty of any frequency standard3, 4, 5. Although many-atom lattice clocks have shown advantages in measurement precision over trapped-ion clocks6, 7, their accuracy has remained 16 times worse8, 9, 10. Here we demonstrate a many-atom system that achieves an accuracy of 6.4 × 10−18, which is not only better than a single-ion-based clock, but also reduces the required measurement time by two orders of magnitude. By systematically evaluating all known sources of uncertainty, including in situ monitoring of the blackbody radiation environment, we improve the accuracy of optical lattice clocks by a factor of 22. This single clock has simultaneously achieved the best known performance in the key characteristics necessary for consideration as a primary standard-stability and accuracy. More stable and accurate atomic clocks will benefit a wide range of fields, such as the realization and distribution of SI units11, the search for time variation of fundamental constants12, clock-based geodesy13 and other precision tests of the fundamental laws of nature. This work also connects to the development of quantum sensors and many-body quantum state engineering14 (such as spin squeezing) to advance measurement precision beyond the standard quantum limit.
Fur and feathers keep animals warm by scattering light - 1 views
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In work that has major implications for improving the performance of building insulation, scientists at the University of Namur in Belgium and the University of Hassan I in Morocco have calculated that hairs that reflect infrared light may contribute significant insulating power to the exceptionally warm winter coats of polar bears and other animals.
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That's quite interesting. Maybe the future of buildings and spacecraft is furry?
US lab developing technology for space traffic control - 0 views
Information Preservation and Weather Forecasting for Black Holes - 2 views
A Different Form of Color Vision in Mantis Shrimp - 4 views
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Mantis shrimp seem to have 12 types of photo-receptive sensors - but this does not really improve their ability to discriminate between colors. Speculation is that they serve as a form of pre-processing for visual information: the brain does not need to decode full color information from just a few channels which would would allow for a smaller brain. I guess technologically the two extremes of light detection would be RGB cameras which are like our eyes and offer good spatial resolution, and spectrometers which have a large amount of color channels but at the cost of spatial resolution. It seems the mantis shrimp uses something that is somewhere between RGB cameras and spectrometers. Could there be a use for this in space?
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> RGB cameras which are like our eyes ...apart from the fact that the spectral response of the eyes is completely different from "RGB" cameras (http://en.wikipedia.org/wiki/File:Cones_SMJ2_E.svg) ... and that the eyes have 4 types of light-sensitive cells, not three (http://en.wikipedia.org/wiki/File:Cone-response.svg) ... and that, unlike cameras, human eye is precise only in a very narrow centre region (http://en.wikipedia.org/wiki/Fovea) ...hmm, apart from relying on tri-stimulus colour perception it seems human eyes are in fact completely different from "RGB cameras" :-) OK sorry for picking on this - that's just the colour science geek in me :-) Now seriously, on one hand the article abstract sounds very interesting, but on the other the statement "Why use 12 color channels when three or four are sufficient for fine color discrimination?" reveals so much ignorance to the very basics of colour science that I'm completely puzzled - in the end, it's a Science article so it should be reasonably scientifically sound, right? Pity I can't access full text... the interesting thing is that more channels mean more information and therefore should require *more* power to process - which is exactly opposite to their theory (as far as I can tell it from the abstract...). So the key is to understand *what* information about light these mantises are collecting and why - definitely it's not "colour" in the sense of human perceptual experience. But in any case - yes, spectrometry has its uses in space :-)
Swiss cheese crystal - 3 views
Underground oceans - 1 views
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Interesting report on water transport in deep see fault lines. Subduction can suck huge quantities of water of water underground where friction and pressure heat it up causing the mantle to partly melt which leads to volcanic activities around the fault zones. Not all the water would make it back up, leading to the possibility that there might be large quantities of water stored within the earths crust.
Computing with silicon neurons: Scientists use artificial nerve cells to classify diffe... - 1 views
Energy Teleportation Overcomes Distance Limit - 0 views
Cognitive computing - 2 views
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Has this not been underway for quite some time now? Not sure if this 'new era' is coming any day soon. Thoughts?
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If they want to give the computers "senses" they should also go ahead and give them a body slightly taller than humans ...and guns. So once they reach a critical level of consciousness they can really go to town... http://0-media-cdn.foolz.us/ffuuka/board/tg/image/1385/54/1385549501025.jpg
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Neural networks!!! However, indeed, "senses" will not make any sense towards human-like computing without bodies that physically interact with the world. That's where most of these things are going wrong. Perception and cognition are for action. Without action coming from the machine side all these ideas simply fail.
Self-healing polymers (video) - 2 views
The complete walkthrough to the game of LIFE - 4 views
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