tag:blogger.com,1999:blog-42184356889313409162024-03-18T03:38:43.224-07:00Submeta NotebookSubmeta Notebooksubmetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.comBlogger1905125tag:blogger.com,1999:blog-4218435688931340916.post-55297153379673249282014-09-25T13:11:00.000-07:002015-04-11T13:11:43.178-07:00‘Cloaking’ device uses ordinary lenses to hide objects across range of angles : NewsCenter<a href="http://www.rochester.edu/newscenter/watch-rochester-cloak-uses-ordinary-lenses-to-hide-objects-across-continuous-range-of-angles-70592/">‘Cloaking’ device uses ordinary lenses to hide objects across range of angles : NewsCenter</a>: “This is the first device that we know of that can do three-dimensional, continuously multidirectional cloaking, which works for transmitting rays in the visible spectrum..."<br />
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In order to both cloak an object and leave the background undisturbed, the researchers determined the lens type and power needed, as well as the precise distance to separate the four lenses. To test their device, they placed the cloaked object in front of a grid background. As they looked through the lenses and changed their viewing angle by moving from side to side, the grid shifted accordingly as if the cloaking device was not there. There was no discontinuity in the grid lines behind the cloaked object, compared to the background, and the grid sizes (magnification) matched.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com3tag:blogger.com,1999:blog-4218435688931340916.post-19408885001576650712014-09-24T13:05:00.000-07:002015-04-11T13:06:18.253-07:00Researcher shows that black holes do not exist<a href="http://phys.org/news/2014-09-black-holes.html">Researcher shows that black holes do not exist</a>: She and Hawking both agree that as a star collapses under its own gravity, it produces Hawking radiation. However, in her new work, Mersini-Houghton shows that by giving off this radiation, the star also sheds mass. So much so that as it shrinks it no longer has the density to become a black hole.<br />
Before a black hole can form, the dying star swells one last time and then explodes. A singularity never forms and neither does an event horizon.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com1tag:blogger.com,1999:blog-4218435688931340916.post-68709609394967850592014-09-23T12:57:00.000-07:002015-04-11T12:58:25.138-07:00Evidence for cosmic inflation wanes | Science/AAAS | News<a href="http://news.sciencemag.org/physics/2014/09/evidence-cosmic-inflation-wanes?rss=1">Evidence for cosmic inflation wanes | Science/AAAS | News</a>: Now, researchers from the European Space Agency's Planck spacecraft have shown that radiation from dust in our galaxy accounts for some, and possibly all, of the BICEP signal.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-9565726573363531502014-09-19T12:55:00.000-07:002015-04-11T12:56:28.906-07:00The Great Cold Spot in the cosmic microwave background<a href="http://phys.org/news/2014-09-great-cold-cosmic-microwave-background.html">The Great Cold Spot in the cosmic microwave background</a>: The CMB cold spot is not particularly colder than other cold regions of the CMB, but it is unusual because it is a particularly cold region surrounded by a rather warm region. Simulations of random fluctuations in a CMB estimate that the odds of such a cold spot happening in the universe is about 1 in 100. So it's possible that it is just a random fluctuation. But the 1% odds is small enough that some astronomers have looked for a possible cause, and these ideas have ranged from the mundane to the wild.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-69606985784856438282014-09-11T12:49:00.000-07:002015-04-11T12:51:39.029-07:00Defying physics, engineers prove a magnetic field for light<a href="http://phys.org/news/2014-09-defying-physics-magnetic-field.html">Defying physics, engineers prove a magnetic field for light</a>: When a light wave travels under normal conditions, its phase is proportional to how far it traveled, but it is unaffected by what path it has taken. Just like a magnetic field causes a current to switch direction, the researchers showed that by modulating the light with their device, they could make the phase of the light change not only as a function of distance traveled, but also by the shape of its path.<br />
An array of such modulators would be powerful enough to create a field for light that is equivalent to the magnetic field for electrons; phases of light could be controlled arbitrarily by each of the modulators. This means that the phase of transmitted light could depend on the path it has taken from point A to point B, Lipson explained.<br />
<br />submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com3tag:blogger.com,1999:blog-4218435688931340916.post-91660098599624277062014-09-10T12:48:00.000-07:002015-04-11T12:48:37.814-07:00'Solid light' could compute previously unsolvable problems - ScienceBlog.com<a href="http://scienceblog.com/74321/solid-light-compute-previously-unsolvable-problems/#JDduCb8DohkJoGWH.97">'Solid light' could compute previously unsolvable problems - ScienceBlog.com</a>: To build their machine, the researchers created a structure made of superconducting materials that contains 100 billion atoms engineered to act as a single “artificial atom.” They placed the artificial atom close to a superconducting wire containing photons.<br />
By the rules of quantum mechanics, the photons on the wire inherit some of the properties of the artificial atom – in a sense linking them. Normally photons do not interact with each other, but in this system the researchers are able to create new behavior in which the photons begin to interact in some ways like particles.<br />
“We have used this blending together of the photons and the atom to artificially devise strong interactions among the photons,” said Darius Sadri, a postdoctoral researcher and one of the authors. “These interactions then lead to completely new collective behavior for light – akin to the phases of matter, like liquids and crystals, studied in condensed matter physics.”<br />
<br />submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-52342927582587167422014-08-20T22:32:00.000-07:002014-08-30T22:32:18.510-07:00Type Ia supernovae stem from the explosion of white dwarfs coupled with twin stars<a href="http://phys.org/news/2014-08-ia-supernovae-stem-explosion-white.html">Type Ia supernovae stem from the explosion of white dwarfs coupled with twin stars</a>: A new model postulating the fusion of two white dwarfs is now challenging the predominant one, consisting of a white dwarf and a normal star. The new scenario does not imply the existence of a maximum mass limit and will not, therefore, necessarily produce explosions of similar luminosity...<br />
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"If these results were to gain general acceptance, the cosmological consequences would be weighty, because the use of type Ia supernovae to measure distances would come into question," the researcher concludes.<br />
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<br />submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-55982491094512082972014-08-14T22:06:00.000-07:002014-08-30T22:07:46.560-07:00Inside the cell, an ocean of buffeting waves<a href="http://phys.org/news/2014-08-cell-ocean-buffeting.html">Inside the cell, an ocean of buffeting waves</a>: The cytoplasm is actually an elastic gel, it turns out, so it puts up some resistance to simple diffusion. But energetic processes elsewhere in the cell—in the cytoskeleton, especially—create random but powerful waves in the cytoplasm, pushing on proteins and organelles alike. Like flotsam and jetsam buffeted by the wakes of passing ships, suspended particles scatter much more quickly and widely than they would in a calm sea.<br />
<br />submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-122221367626092442014-08-14T21:59:00.000-07:002014-08-30T22:00:02.594-07:00Watch a swarm of 1000 mini-robots assemble into shapes - tech - 14 August 2014 - New Scientist<a href="http://www.newscientist.com/article/dn26060-watch-a-swarm-of-1000-minirobots-assemble-into-shapes.html?">Watch a swarm of 1000 mini-robots assemble into shapes - tech - 14 August 2014 - New Scientist</a>: To do the assembling, the desired end shape is first transmitted to all the robots and then four stationary robots are positioned by hand to mark the shape's starting point. Next, some of the robots start to shuffle until they reach a place-holding robot and then fan out from that point to stop in the right place. Each robot can only communicate with the others nearby. Successive robots build up the shape by stopping near the robots already in place. It can take about 12 hours for 1000 robots to fill in a pattern.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-64071749019724406832014-08-13T15:00:00.000-07:002014-08-30T15:00:51.309-07:00Fields medallist: How Rubik's cube inspired new maths - opinion - 13 August 2014 - New Scientist<a href="http://www.newscientist.com/article/mg22329824.600-fields-medallist-how-rubiks-cube-inspired-new-maths.html#.VAJJcoBdU00">Fields medallist: How Rubik's cube inspired new maths - opinion - 13 August 2014 - New Scientist</a>submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-88798274984771039942014-08-11T14:57:00.000-07:002014-08-30T14:57:57.259-07:00Scientists create artificial brain out of spongy goo | Science/AAAS | News<a href="http://news.sciencemag.org/brain-behavior/2014/08/scientists-create-artificial-brain-out-spongy-goo?rss=1">Scientists create artificial brain out of spongy goo | Science/AAAS | News</a>: The rings are engineered to mimic the structure and function of the six layers of human cortical brain tissue. Scientists coaxed neurons (right) to grow around stiff, porous matrices made of silk proteins immersed in collagen gel. Then, they colored the layers with food dye and pieced them together like a jigsaw puzzle. By tweaking the size and orientation of matrix pores, researchers attempted to emulate variations of cellular structure and function in a real cortex. Unlike flat neuron cultures grown in petri dishes, the structure provides cells with something to cling to as they branch out and make connections, forming complex, 3D networks that more closely mimic real neural circuits, the authors say.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-61699578971761936912014-08-09T14:55:00.000-07:002014-08-30T14:56:05.812-07:00Ask Ethan #49: Do the cosmic unknowns cast doubt on the Big Bang? — Starts With A Bang! — Medium<a href="https://medium.com/starts-with-a-bang/ask-ethan-49-do-the-cosmic-unknowns-cast-doubt-on-the-big-bang-654f3f9e63a9">Ask Ethan #49: Do the cosmic unknowns cast doubt on the Big Bang? — Starts With A Bang! — Medium</a>: ...all isotropic, homogeneous spacetimes (that is, solutions to GR that are roughly the same at all locations in space and in all directions) must either have expanding or contracting space...<br />
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All of this — the whole story I outlined above — would be true regardless of what else is actually in your Universe. The only things that change due to dark matter and dark energy are the following...<br />
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<br />submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-63214474951986714112014-08-08T14:20:00.000-07:002014-08-30T14:21:02.591-07:00IBM Scientists Show Blueprints for Brainlike Computing - MIT Technology Review<a href="http://m.technologyreview.com/news/517876/ibm-scientists-show-blueprints-for-brainlike-computing/">IBM Scientists Show Blueprints for Brainlike Computing - MIT Technology Review</a>: “Programs” are written using special blueprints called corelets. Each corelet specifies the basic functioning of a network of neurosynaptic cores. Individual corelets can be linked into more and more complex structures—nested, Modha says, “like Russian dolls.”submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-82706137098422993572014-08-08T14:14:00.000-07:002014-08-30T14:14:52.397-07:00Terahertz Chip Identifies Short Strands of DNA | MIT Technology Review<a href="http://www.technologyreview.com/view/529926/terahertz-chip-identifies-short-strands-of-dna/">Terahertz Chip Identifies Short Strands of DNA | MIT Technology Review</a>: They say that the sequence of bases in an oligonucleotide determines the way in which the strand resonates at frequencies in the terahertz range...<br />
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...they have tested it using a device they call a silicon nanosandwich, a quantum well of p-type silicon surrounded by barriers doped with boron. This produces terahertz radiation inside the well where the oligonucleotide is deposited at a concentration that allows a single molecule to enter.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com1tag:blogger.com,1999:blog-4218435688931340916.post-5750202853890140562014-08-07T14:18:00.000-07:002014-08-30T14:18:46.222-07:00‘Unparticles’ May Hold The Key To Superconductivity, Say Physicists — The Physics arXiv Blog — Medium<a href="https://medium.com/the-physics-arxiv-blog/unparticles-may-hold-the-key-to-superconductivity-say-physicists-fa50cac115eb">‘Unparticles’ May Hold The Key To Superconductivity, Say Physicists — The Physics arXiv Blog — Medium</a>: Georgi’s concept of unparticles comes about by conjecturing that some “stuff” may have mass, energy and momentum and yet also be scale invariant...<br />
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Physicists have long known that the behaviour of electrons in high-temperature superconductors is extremely complex...<br />
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What LeBlanc and Grushin show is that under certain conditions the interaction between these entities can become scale invariant and is therefore described by the physics of unparticles. In very simple terms, when that happens, material properties such as resistance no longer depend on the length scales involved. So if electrons move without resistance on a tiny scale, they should also move without resistance on much larger scales too. Hence the phenomenon of superconductivity.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com1tag:blogger.com,1999:blog-4218435688931340916.post-25302647074570092242014-08-07T14:09:00.000-07:002014-08-30T14:10:27.415-07:00Self-organising origami robot unfolds itself… and walks - tech - 07 August 2014 - New Scientist<a href="http://www.newscientist.com/article/dn26024-selforganising-origami-robot-unfolds-itself-and-walks.html#.VAI9oYBdU00">Self-organising origami robot unfolds itself… and walks - tech - 07 August 2014 - New Scientist</a>submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com1tag:blogger.com,1999:blog-4218435688931340916.post-84227320838342692682014-08-06T16:48:00.000-07:002014-08-17T16:48:56.746-07:00Cool your jets: NASA's quantum spaceship is doubtful - space - 06 August 2014 - New Scientist<a href="http://www.newscientist.com/article/dn26009-cool-your-jets-nasas-quantum-spaceship-is-doubtful.html#.U_E--YBdU00">Cool your jets: NASA's quantum spaceship is doubtful - space - 06 August 2014 - New Scientist</a>: ...as Baez points out, this new device in question wasn't even tested in a vacuum! That's extremely important; assuming the measurements are real, the thrust seen could be due to air being warmed up and moving around.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-14218231281118349492014-08-05T14:06:00.000-07:002014-08-30T14:06:18.582-07:00Physicists eye neural fly data, find formula for Zipf's law<a href="http://phys.org/news/2014-08-physicists-eye-neural-formula-zipf.html">Physicists eye neural fly data, find formula for Zipf's law</a>: ...George Zipf... found that if you rank words in a language in order of their popularity, a strange pattern emerges: The most popular word is used twice as often as the second most popular, and three times as much as the third-ranked word, and so on. This same rank vs. frequency rule was also found to apply to many other social systems...<br />
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"We showed mathematically that the system becomes Zipfian when you're recording the activity of many units, such as neurons, and all of the units are responding to the same variable," Nemenman says. "The fact that Zipf's law will occur in a system with just 40 or 50 such units shows that biological units are in some sense special – they must be adapted to the outside world."<br />
<br />submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-22118734664335818412014-08-04T16:53:00.000-07:002014-08-17T16:53:59.903-07:00Don't Get Too Excited About NASA's New Miracle Engine<a href="http://space.io9.com/a-new-thruster-pushes-against-virtual-particles-or-1615361369/1615513781/+rtgonzalez">Don't Get Too Excited About NASA's New Miracle Engine</a>: [The researchers] hook up a gizmo with all sorts of electromagnetic fields fluctuating around, then claim to measure an extremely tiny thrust (about the weight of a single grain of sand), which occurs even for the test article that wasn't supposed to produce any thrust at all.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-8604852145613590172014-08-01T16:45:00.000-07:002014-08-17T16:46:03.878-07:00Fuel-Less Space Drive May Actually Work, Says NASA | Popular Science<a href="http://www.popsci.com/article/technology/fuel-less-space-drive-may-actually-work-says-nasa">Fuel-Less Space Drive May Actually Work, Says NASA | Popular Science</a>: The design is seemingly based on the EmDrive, which was originally created by British scientist Roger Shawyer. The drive is supposed to convert electric power into thrust by bouncing microwaves off the walls of a closed container, and Fetta’s drive, while different, does relatively the same thing...<br />
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In a paper presented at the 50th Joint Propulsion Conference in Cleveland, Ohio, NASA apparently gave Fetta’s design their stamp of approval after testing his drive.�Granted, their tests only produced a small amount of thrust (between 30 and�50 micro-Newtons), but that’s still pretty impressive since absolutely no propellant was needed...<br />
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He notes that these experiments are pretty easy to mess up, since you basically have to recreate the vacuum of space for the results to be right. Any interference from an outside factor could affect the results...<br />
<br />submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-75340494306315919722014-07-30T16:38:00.000-07:002014-08-17T16:42:27.103-07:00The Curious Evolution of Artificial Life | MIT Technology Review<a href="http://www.technologyreview.com/view/529491/the-curious-evolution-of-artificial-life/">The Curious Evolution of Artificial Life | MIT Technology Review</a>: He divides the history of Web-based artificial life into two periods: before and after 2005, a characterization that corresponds roughly with the emergence of Web 2.0 and the collaborative behaviors that it allows.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-79064468379602457252014-07-27T16:22:00.000-07:002014-08-17T16:22:46.184-07:00How bird flocks are like liquid helium | Science/AAAS | News<a href="http://news.sciencemag.org/math/2014/07/how-bird-flocks-are-liquid-helium?rss=1">How bird flocks are like liquid helium | Science/AAAS | News</a>: Using tracking software on the recorded video, the team could pinpoint when and where individuals decide to turn, information that enabled them to follow how the decision sweeps through the flock. The tracking data showed that the message to turn started from a handful of birds and swept through the flock at a constant speed between 20 and 40 meters per second. That means that for a group of 400 birds, it takes just a little more than a half-second for the whole flock to turn...<br />
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The team proposes that instead of copying the direction in which a neighbor flies, a bird copies how sharply a neighbor turns...<br />
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Interestingly, Cavagna adds, the new model is mathematically identical to the equations that describe superfluid helium.<br />
<br />submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-42006668896376360682014-07-23T17:00:00.000-07:002014-08-16T17:01:29.102-07:00Quantum split: Particle this way, properties that way - physics-math - 23 July 2014 - New Scientist<a href="http://www.newscientist.com/article/mg22329794.600-quantum-split-particle-this-way-properties-that-way.html?full=true#.U-_rZ4BdU00">Quantum split: Particle this way, properties that way - physics-math - 23 July 2014 - New Scientist</a>: In Grenoble, the Vienna team used a feeble magnetic field and a weakly interacting neutron absorber to make the weak measurements. They found that when they put the absorber in one path of the interferometer (say left), there was a discernible effect at the output. But when they put it in the right path, it had no such effect. The neutrons were travelling in one path only.<br />
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Next, the experimenters introduced a weak magnetic field near each arm of the interferometer, to interact with the spin of the neutrons. When they did this in the left path, there was no change in the interferometer's output. If they introduced the magnetic field in the right path, though, there was a change: the magnetic field had interacted with the spin. In other words, they had confirmed that the spin had chosen the path not taken by the parent neutron...submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com1tag:blogger.com,1999:blog-4218435688931340916.post-25343856401301736902014-07-23T16:10:00.000-07:002014-08-17T16:10:52.741-07:00Black Holes Aren’t Black After All, Say Theoretical Physicists — The Physics arXiv Blog — Medium<a href="https://medium.com/the-physics-arxiv-blog/black-holes-arent-black-after-all-say-theoretical-physicists-d0758c7c88b5">Black Holes Aren’t Black After All, Say Theoretical Physicists — The Physics arXiv Blog — Medium</a>: Stephen Hawking proposed a potential solution earlier this year. His idea is that gravitational collapse can never continue beyond the so-called event horizon of a black hole beyond which information is lost. Gravitational collapse would approach the boundary but never go beyond it...<br />
<br />submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com0tag:blogger.com,1999:blog-4218435688931340916.post-73574786569033030262014-07-22T16:35:00.000-07:002014-08-16T16:36:27.935-07:00Lasers make fibre optic tubes out of thin air - tech - 22 July 2014 - New Scientist<a href="http://www.newscientist.com/article/dn25931-lasers-make-fibre-optic-tubes-out-of-thin-air.html#.U-_mqYBdU00">Lasers make fibre optic tubes out of thin air - tech - 22 July 2014 - New Scientist</a>: The team shone four lasers in a square arrangement, heating air molecules and creating a low-density ring around a denser core of air. Light bounces around the dense core just like in a fibre.<br />
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The air fibre lasts for a few milliseconds – more than enough to send a signal.submetahttp://www.blogger.com/profile/14739624063574448512noreply@blogger.com13