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johannessimon81

Integral catches dead star exploding in a blaze of glory - 1 views

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    Astronomers using ESA's Integral gamma-ray observatory have demonstrated beyond doubt that dead stars known as white dwarfs can reignite and explode as supernovae. The finding came after the unique signature of gamma rays from the radioactive elements created in one of these ex...
Paul N

Help Scientists Track Cosmic Ray Particles Using Your Smartphone Camera - 2 views

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    Looks like crowdsourcing for astronomy stuff is already being done.
Marcus Maertens

Solving the Mystery of Cosmic Rays | | UW-Madison - 1 views

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    The ice-cube observatory in Antarctica reveals the source of high energy cosmic neutrinos. Spoiler: its Blazars!
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    Hate spoliers!
LeopoldS

Ultra-efficient ionization of heavy atoms by intense X-ray free-electron laser pulses :... - 0 views

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    Extremely charged Xe ions by stripping off more electrons than previously thought possible ...
johannessimon81

Nuclear isomer - 2 views

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    We had a short discussion yesterday about using nuclear isomers as batteries for spacecraft. The principle is that energy is stored as an excitation of the nucleus which can then release the energy as a gamma-photon. However angular momentum has to be conserved an this suppresses the decay strongly - making these states stable up to 10^35 longer than a typical decay.
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    The key is the triggering of the dacay wheras the triggering comsumes less energy than the decay provides. The x-ray based triggering of the gamma photon decay turned out to be quite controversial and needs significantly more scientific attention.
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    I think that there should be some references and traces of the discussions we had on this on the shared drive or wiki ... One other aspect: converting the omnidirectional gamma bursts into useful energy ....
Marcus Maertens

Mars Mission May Use 'Poop Shield' to Block Cosmic Rays | News & Opinion | PCMag.com - 1 views

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    Quote: "It's a little queasy sounding, but there's no place for that material to go, and it makes great radiation shielding"
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    Judging by the color it probably contains a lot of melanin. ;-)
LeopoldS

Phys. Rev. Lett. 110, 141102 (2013): First Result from the Alpha Magnetic Spectrometer ... - 0 views

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    for Sante to review - or believe in dark matter :-)
johannessimon81

"Natural Light Cloaking for Aquatic and Terrestrial Creatures" - 3 views

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    Cheap and scalable invisibility cloaks being developed. The setup is so trivial that I would almost call it a "trick" (as in "Magicians trick"): 6 prisms of n=1.78 glass. Nontheless, it does the job of cloaking an object at visible wavelengths and from several directions.
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    can we build one?
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    Yes, I just did :-) It is on my desk
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    New video here (smaller file than previous): "https://dl.dropboxusercontent.com/u/58527156/20130613_101701.mp4" Note how close to the center of the field of view the hidden objects are. I am quite surprised that such poor lenses create such a sharp focus.
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    Well.. I would say that it is not "fully cloaking", as the image behind is mirrored as well
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    That just means that you have to double the setup, i.e., put 4 glasses in a row. Of course the obvious drawback is that you can only look at this cloak from one direction.
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    Is this really new? I don't know, but I know that the original idea of cloaking was pretty different. When cloaking as an application of transformation optics became popular people tried to make devices that work for any incidence angle, any polarization and in full wave optics (not just ray approximation). This is really hard to achieve and I guess that the people that tried to make such devices knew exactly that the task becomes almost trivial by dropping at least two of the three conditions above.
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    I think it is very easy to call something trivial when you're not the one who invested considerable time (5 min in my case) to design a cloaking device and fill the coffee mugs with water... Also, I did not really violate that many conditions: true I reduced the number of dimensions in which the device works to 1 (as opposed to the 2 dimensions of many metamaterial cloaks). However the polarization should not be affected in my setup as well as the wave phase and wave vector (so it works in full wave optics) - apart maybe from the imperfect lens distortion, but hey I was improvising.
Marcus Maertens

New Techniques from Google and Ray Kurzweil Are Taking Artificial Intelligence to Anoth... - 1 views

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    Winter is coming... and deep learning, too!
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    "Sergey Brin has said he wants to build a benign version of HAL in 2001: A Space Odyssey" ... didn't they try to do that in that movie called "2001: A Space Odyssey" ?
fichbio

[1610.08323] Evidence for vacuum birefringence from the first optical polarimetry measu... - 3 views

shared by fichbio on 02 Dec 16 - No Cached
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    Abstract: The "Magnificent Seven" (M7) are a group of radio-quiet Isolated Neutron Stars (INSs) discovered in the soft X-rays through their purely thermal surface emission. Owing to the large inferred magnetic fields ($B\approx 10^{13}$ G), radiation from these sources is expected to be substantially polarised, independently on the mechanism actually responsible for the thermal emission.
Guido de Croon

Will robots be smarter than humans by 2029? - 2 views

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    Nice discussion about the singularity. Made me think of drinking coffee with Luis... It raises some issues such as the necessity of embodiment, etc.
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    "Kurzweilians"... LOL. Still not sold on embodiment, btw.
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    The biggest problem with embodiment is that, since the passive walkers (with which it all started), it hasn't delivered anything really interesting...
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    The problem with embodiment is that it's done wrong. Embodiment needs to be treated like big data. More sensors, more data, more processing. Just putting a computer in a robot with a camera and microphone is not embodiment.
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    I like how he attacks Moore's Law. It always looks a bit naive to me if people start to (ab)use it to make their point. No strong opinion about embodiment.
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    @Paul: How would embodiment be done RIGHT?
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    Embodiment has some obvious advantages. For example, in the vision domain many hard problems become easy when you have a body with which you can take actions (like looking at an object you don't immediately recognize from a different angle) - a point already made by researchers such as Aloimonos.and Ballard in the end 80s / beginning 90s. However, embodiment goes further than gathering information and "mental" recognition. In this respect, the evolutionary robotics work by for example Beer is interesting, where an agent discriminates between diamonds and circles by avoiding one and catching the other, without there being a clear "moment" in which the recognition takes place. "Recognition" is a behavioral property there, for which embodiment is obviously important. With embodiment the effort for recognizing an object behaviorally can be divided between the brain and the body, resulting in less computation for the brain. Also the article "Behavioural Categorisation: Behaviour makes up for bad vision" is interesting in this respect. In the field of embodied cognitive science, some say that recognition is constituted by the activation of sensorimotor correlations. I wonder to which extent this is true, and if it is valid for extremely simple creatures to more advanced ones, but it is an interesting idea nonetheless. This being said, if "embodiment" implies having a physical body, then I would argue that it is not a necessary requirement for intelligence. "Situatedness", being able to take (virtual or real) "actions" that influence the "inputs", may be.
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    @Paul While I completely agree about the "embodiment done wrong" (or at least "not exactly correct") part, what you say goes exactly against one of the major claims which are connected with the notion of embodiment (google for "representational bottleneck"). The fact is your brain does *not* have resources to deal with big data. The idea therefore is that it is the body what helps to deal with what to a computer scientist appears like "big data". Understanding how this happens is key. Whether it is the problem of scale or of actually understanding what happens should be quite conclusively shown by the outcomes of the Blue Brain project.
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    Wouldn't one expect that to produce consciousness (even in a lower form) an approach resembling that of nature would be essential? All animals grow from a very simple initial state (just a few cells) and have only a very limited number of sensors AND processing units. This would allow for a fairly simple way to create simple neural networks and to start up stable neural excitation patterns. Over time as complexity of the body (sensors, processors, actuators) increases the system should be able to adapt in a continuous manner and increase its degree of self-awareness and consciousness. On the other hand, building a simulated brain that resembles (parts of) the human one in its final state seems to me like taking a person who is just dead and trying to restart the brain by means of electric shocks.
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    Actually on a neuronal level all information gets processed. Not all of it makes it into "conscious" processing or attention. Whatever makes it into conscious processing is a highly reduced representation of the data you get. However that doesn't get lost. Basic, low processed data forms the basis of proprioception and reflexes. Every step you take is a macro command your brain issues to the intricate sensory-motor system that puts your legs in motion by actuating every muscle and correcting every step deviation from its desired trajectory using the complicated system of nerve endings and motor commands. Reflexes which were build over the years, as those massive amounts of data slowly get integrated into the nervous system and the the incipient parts of the brain. But without all those sensors scattered throughout the body, all the little inputs in massive amounts that slowly get filtered through, you would not be able to experience your body, and experience the world. Every concept that you conjure up from your mind is a sort of loose association of your sensorimotor input. How can a robot understand the concept of a strawberry if all it can perceive of it is its shape and color and maybe the sound that it makes as it gets squished? How can you understand the "abstract" notion of strawberry without the incredibly sensible tactile feel, without the act of ripping off the stem, without the motor action of taking it to our mouths, without its texture and taste? When we as humans summon the strawberry thought, all of these concepts and ideas converge (distributed throughout the neurons in our minds) to form this abstract concept formed out of all of these many many correlations. A robot with no touch, no taste, no delicate articulate motions, no "serious" way to interact with and perceive its environment, no massive flow of information from which to chose and and reduce, will never attain human level intelligence. That's point 1. Point 2 is that mere pattern recogn
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    All information *that gets processed* gets processed but now we arrived at a tautology. The whole problem is ultimately nobody knows what gets processed (not to mention how). In fact an absolute statement "all information" gets processed is very easy to dismiss because the characteristics of our sensors are such that a lot of information is filtered out already at the input level (e.g. eyes). I'm not saying it's not a valid and even interesting assumption, but it's still just an assumption and the next step is to explore scientifically where it leads you. And until you show its superiority experimentally it's as good as all other alternative assumptions you can make. I only wanted to point out is that "more processing" is not exactly compatible with some of the fundamental assumptions of the embodiment. I recommend Wilson, 2002 as a crash course.
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    These deal with different things in human intelligence. One is the depth of the intelligence (how much of the bigger picture can you see, how abstract can you form concept and ideas), another is the breadth of the intelligence (how well can you actually generalize, how encompassing those concepts are and what is the level of detail in which you perceive all the information you have) and another is the relevance of the information (this is where the embodiment comes in. What you do is to a purpose, tied into the environment and ultimately linked to survival). As far as I see it, these form the pillars of human intelligence, and of the intelligence of biological beings. They are quite contradictory to each other mainly due to physical constraints (such as for example energy usage, and training time). "More processing" is not exactly compatible with some aspects of embodiment, but it is important for human level intelligence. Embodiment is necessary for establishing an environmental context of actions, a constraint space if you will, failure of human minds (i.e. schizophrenia) is ultimately a failure of perceived embodiment. What we do know is that we perform a lot of compression and a lot of integration on a lot of data in an environmental coupling. Imo, take any of these parts out, and you cannot attain human+ intelligence. Vary the quantities and you'll obtain different manifestations of intelligence, from cockroach to cat to google to random quake bot. Increase them all beyond human levels and you're on your way towards the singularity.
Thijs Versloot

Black metals - 3 views

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    Using random nanostructuring highly absorptive materials were made which are of interest for photovoltaic or thermovoltaic applications
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    Yes, Black Metal is very good - pure hate! \m/
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    Yes! Black Metal... definitely something the ACT should look into
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    Black Metal...sounds like something for the ACT Magic Cards. But apart from that - is it possible to shift the PV type of absorption into gamma ray spectrum?
Nicholas Lan

amines found to be far more important than cosmic rays in cloud formation - 0 views

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    relationship between living organisms and cloud formation seems interesting
jessyjemy

What happens to your brain on the way to Mars - 1 views

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    This study from NASA shows that cosmic rays have a deleterious effect on the brain, more than expected, resulting in in symptoms similar to dementia (memory loss, decline in problem solving skills, general cognitive functions). A reason more to investigate into hibernation?
Ma Ru

"discovery of an exceptional object in our cosmic neighborhood" - 2 views

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    This enigmatic statement is said to have generated a lot of hype in the blogosphere... in case you want to watch, 12:30 EST is 17:30 GMT and 18:30 CET.
pacome delva

Mapping Turbulence in the Solar Wind - 0 views

  • a team reports studying the turbulent flow of solar wind particles by monitoring the accompanying waves of magnetic field. The team used a cluster of satellites to measure the field in unprecedented spatial detail. They found that the waves aren't equally strong in all directions but are larger in certain preferred directions, as theorists had predicted. The observation will help astrophysicists better understand the consequences of the solar wind, including its effect on the transmission of cosmic rays, particles that arrive at Earth from elsewhere in our galaxy.
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