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Thijs Versloot

Time 'Emerges' from #Quantum Entanglement #arXiv - 1 views

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    Time is an emergent phenomenon that is a side effect of quantum entanglement, say physicists. And they have the first exprimental results to prove it
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    I always feel like people make too big a deal out of entanglement. In my opinion it is just a combination of a conserved quantity and an initial lack of knowledge. Imagine that I had a machine that always creates one blue and one red ping-pong ball at the same time (|b > and |r > respectively). The machine now puts both balls into identical packages (so I cannot observe them) and one of the packages is sent to Tokio. I did not know which ball was sent to Tokio and which stayed with me - they are in a superposition (|br >+|rb >), meaning that either the blue ball is with me and the red one in Tokio or vice versa - they are entangled. So far no magic has happened. Now I call my friend in Tokio who got the ball: "What color was the ball you received in that package?" He replies: "The ball that I got was blue. Why did you send me ball in the first place?" Now, the fact that he told me makes the superpositon wavefunction collapse (yes, that is what the Copenhagen interpretation would tell us). As a result I know without opening my box that it contains a red ball. But this is really because there is an underlying conservation law and because now I know the other state. I don't see how just looking at the conserved quantity I am in a timeless state outside of the 'universe' - this is just one way of interpreting it. By the way, the wave function for my box with the undetermined ball does not collapse when the other ball is observed by my friend in Tokio. Only when he tells me does the wavefunction collapse - he did not even know that I had a complementary ball. On the other hand if he knew about the way the experiment was conducted then he would have known that I had to have a red ball - the wavefunction collapses as soon as he observed his ball. For him it is determined that my ball must be red. For me however the superposition is intact until he tells me. ;-)
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    Sorry, Johannes, you just develop a simple hidden-parameters theory and it's experimentally proven that these don't work. Entangeled states are neither the blue nor the red ball they are really bluered (or redblue) till the point the measurement is done.
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    Hm, to me this looks like a bad joke... The "emergent time" concept used is still the old proposal by Page and Whotters where time emerges from something fundamentally unobservable (the wave function of the Universe). That's as good as claiming that time emerges from God. If I understand correctly, the paper now deals with the situation where a finite system is taken as "Mini-Universe" and the experimentalist in the lab can play "God of the Mini-Universe". This works, of course, but it doesn't really tell us anything about emergent time, does it?
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    Actually, it has not been proven conclusively that hidden variable theories don' work - although this is the opinion of most physicists these days. But a non-local hidden variable would still be allowed - I don't see why that could not be equivalent to a conserved quantity within the system. As far as the two balls go it is fine to say they are undetermined instead of saying they are in bluered or redblue state - for all intents and purposes it does not affect us (because if it would the wavefunction would have collapsed) so we can't say anything about it in the first place.
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    Non-local hidden variables may work, but in my opinion they don't add anything to the picture. The (at least to non-physicists) contraintuitive fact that there cannot be a variable that determines ab initio the color of the ball going to Tokio will remain (in your example this may not even be true since the example is too simple...).
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    I guess I tentatively agree with you on both points. In the end there might anyway be surprisingly little overlap between the way that we describe what nature does and HOW it does it... :-D
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    Congratulations! 100% agree.
Francesco Biscani

Apple's Mistake - 5 views

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    Nice opinion piece.
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    nice indeed .... especially like: "They make such great stuff, but they're such assholes. Do I really want to support this company? Should Apple care what people like me think? What difference does it make if they alienate a small minority of their users? There are a couple reasons they should care. One is that these users are the people they want as employees. If your company seems evil, the best programmers won't work for you. That hurt Microsoft a lot starting in the 90s. Programmers started to feel sheepish about working there. It seemed like selling out. When people from Microsoft were talking to other programmers and they mentioned where they worked, there were a lot of self-deprecating jokes about having gone over to the dark side. But the real problem for Microsoft wasn't the embarrassment of the people they hired. It was the people they never got. And you know who got them? Google and Apple. If Microsoft was the Empire, they were the Rebel Alliance. And it's largely because they got more of the best people that Google and Apple are doing so much better than Microsoft today. Why are programmers so fussy about their employers' morals? Partly because they can afford to be. The best programmers can work wherever they want. They don't have to work for a company they have qualms about. But the other reason programmers are fussy, I think, is that evil begets stupidity. An organization that wins by exercising power starts to lose the ability to win by doing better work. And it's not fun for a smart person to work in a place where the best ideas aren't the ones that win."
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    Poor programmers can complain, but they will keep developing applications for iPhone as long as their bosses will tell them to do so... From my experience in mobile software development I assure you it's not the pain of the programmer that dictates what is done, but the customer's demand. Even though like this the quality of applications is somewhat worse than it could be, clients won't complain as they have no reference point. And things will stay as they are: apple censoring the applications, clients paying for stuff that "sometimes just does not work" (it's normal, isn't it??), and programmers complaining, but obediently making iPhone apps...
Luís F. Simões

Inferring individual rules from collective behavior - 2 views

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    "We fit data to zonal interaction models and characterize which individual interaction forces suffice to explain observed spatial patterns." You can get the paper from the first author's website: http://people.stfx.ca/rlukeman/research.htm
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    PNAS? Didnt strike me as sth very new though... We should refer to it in the roots study though: "Social organisms form striking aggregation patterns, displaying cohesion, polarization, and collective intelligence. Determining how they do so in nature is challenging; a plethora of simulation studies displaying life-like swarm behavior lack rigorous comparison with actual data because collecting field data of sufficient quality has been a bottleneck." For roots it is NO bottleneck :) Tobias was right :)
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    Here they assume all relevant variables influencing behaviour are being observed. Namely, the relative positions and orientations of all ducks in the swarm. So, they make movies of the swarm's movements, process them, and them fit the models to that data. In the roots, though we can observe the complete final structure, or even obtain time-lapse movies showing how that structure came out to be, getting the measurements of all relevant soil variables (nitrogen, phosphorus, ...) throughout the soil, and over time, would be extremely difficult. So I guess a replication of the kind of work they did, but for the roots, would be hard. Nice reference though.
Juxi Leitner

InfoQ: A Crash Course in Modern Hardware - 3 views

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    for francesco ;) though i guess he knows it all already so for the others who wanna know too
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    Cool, lots of useful info in there. Though, never having programmed in Java before, I wonder if one can go that low-level in Java?
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    oh I don't think so but it is interesting for the JVM I guess
Francesco Biscani

What Should We Teach New Software Developers? Why? | January 2010 | Communications of t... - 3 views

shared by Francesco Biscani on 15 Jan 10 - Cached
Dario Izzo liked it
  • Industry wants to rely on tried-and-true tools and techniques, but is also addicted to dreams of "silver bullets," "transformative breakthroughs," "killer apps," and so forth.
  • This leads to immense conservatism in the choice of basic tools (such as programming languages and operating systems) and a desire for monocultures (to minimize training and deployment costs).
  • The idea of software development as an assembly line manned by semi-skilled interchangeable workers is fundamentally flawed and wasteful.
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    Nice opinion piece by the creator of C++ Bjarne Stroustrup. Substitute "industry" with "science" and many considerations still apply :)
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    "for many, "programming" has become a strange combination of unprincipled hacking and invoking other people's libraries (with only the vaguest idea of what's going on). The notions of "maintenance" and "code quality" are typically forgotten or poorly understood. " ... seen so many of those students :( and ad "My suggestion is to define a structure of CS education based on a core plus specializations and application areas", I am not saying the austrian university system is good, but e.g. the CS degrees in Vienna are done like this, there is a core which is the same for everybody 4-5 semester, and then you specialise in e.g. software engineering or computational mgmt and so forth, and then after 2 semester you specialize again into one of I think 7 or 8 master degrees ... It does not make it easy for industry to hire people, as I have noticed, they sometimes really have no clue what the difference between Software Engineering is compared to Computational Intelligence, at least in HR :/
Luzi Bergamin

Vivos Underground Survival Shelter Network for 2012 and Beyond - 0 views

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    The world will end on 21.12.2012, the Maya knew this (http://www.youtube.com/watch?v=04OilEWckAU in German,) so be prepared! There should be an extra shelter for all (Ex-)ACT members. This would be real fun!! Endless strategic meetings on how to survive after apocalypse!
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    No, Luzi, there was an error in the profecy transcription... they meant that Italy would end in 2012, not the world..... and they seem to be quite right according to most observers. I am actually surprised it lasted so long!!!
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    Of course one of the major reasons behind the apocalypse will be European football championship taking place in Poland+Ukraine...
Juxi Leitner

Open Source Satellite Initiative | machine project - 3 views

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    All the satellite-related systems (except for the rocket to launch it) are DIY programs -- designed so that regular people may also have the chance of developing and eventually launching their own.
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    The book is actually funny to read ... but this is not serious! Is it ?
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    I was saying that mainly because of some flaws - the piggy-pack installation, no dedicated stage, the limited control, ... It is so far very funny, but once he can fill all the gaps, it should be an excellent initiative - although careful about the debris if anyone has its own ;p
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    his quote: "when art becomes practical, we call it technology; when technology becomes useless, we call it art" ... this is probably the later one ....
Luís F. Simões

Seminar: You and Your Research, Dr. Richard W. Hamming (March 7, 1986) - 10 views

  • This talk centered on Hamming's observations and research on the question "Why do so few scientists make significant contributions and so many are forgotten in the long run?" From his more than forty years of experience, thirty of which were at Bell Laboratories, he has made a number of direct observations, asked very pointed questions of scientists about what, how, and why they did things, studied the lives of great scientists and great contributions, and has done introspection and studied theories of creativity. The talk is about what he has learned in terms of the properties of the individual scientists, their abilities, traits, working habits, attitudes, and philosophy.
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    Here's the link related to one of the lunch time discussions. I recommend it to every single one of you. I promise it will be worth your time. If you're lazy, you have a summary here (good stuff also in the references, have a look at them):      Erren TC, Cullen P, Erren M, Bourne PE (2007) Ten Simple Rules for Doing Your Best Research, According to Hamming. PLoS Comput Biol 3(10): e213.
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    I'm also pretty sure that the ones who are remembered are not the ones who tried to be... so why all these rules !? I think it's bullshit...
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    The seminar is not a manual on how to achieve fame, but rather an analysis on how others were able to perform very significant work. The two things are in some cases related, but the seminar's focus is on the second.
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    Then read a good book on the life of Copernic, it's the anti-manual of Hamming... he breaks all the rules !
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    honestly I think that some of these rules actually make sense indeed ... but I am always curious to get a good book recommendation (which book of Copernic would you recommend?) btw Pacome: we are in Paris ... in case you have some time ...
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    I warmly recommend this book, a bit old but fascinating: The sleepwalkers from Arthur Koestler. It shows that progress in science is not straight and do not obey any rule... It is not as rational as most of people seem to believe today. http://www.amazon.com/Sleepwalkers-History-Changing-Universe-Compass/dp/0140192468/ref=sr_1_1?ie=UTF8&qid=1294835558&sr=8-1 Otherwise yes I have some time ! my phone number: 0699428926 We live around Denfert-Rochereau and Montparnasse. We could go for a beer this evening ?
Ma Ru

Dark Matter or Black Hole Propulsion? - 1 views

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    Anyone out there still doing propulsion stuff? Two more papers just waiting to get busted... http://arxiv.org/abs/0908.1429v1 http://arxiv.org/abs/0908.1803
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    What an awful bunch of complete nonsense!!! But I don't think anybody wants to hear MY opinion on this...
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    wow, is this serious at all...!?
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    Are you joking?? The BH drive propses a BH with a lifetime of about an year, just 10^7 tons, peanuts!! Then you have to produce it, better not on Earth, so you do this in space, with a laser that produces an equivalent of 10^9 tons highly foucussed, even more peanuts!! Reasonable losses in the production process (probably 99,999%) are not yet taken into account. Engineering problems... :-) The DM drive is even better, they want to collect DM and compress it in a propulsion chamber. Very easy to collect and compress a gas of particles that traverse the Earth without any interaction. Perhaps if the walls of the chamber are made of artificial BHs?? Who knows??
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    WRONG!!! we are all just WAITING for your opinion on this ....!!!
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    well, yes my remark was ironic... I'm surprised they did a magazine on these concepts...! But the press is always waiting for sensational. They do not even wait for the work to be peer-reviewed now to make an article on it ! This is one of the bad sides of arxiv in my opinion. It's like a journalist that make an article with a copy-paste in wikipedia ! Anyway, this is of course complete bullsh..., and I would have laughed if I had read this in a sci-fi book... but in a "serious" article i'm crying... For the DM i do not agree with your remark Luzi. It's not dark energy they want to use. The DM is baryonic, it's dark just because it's cold so we don't see it by usual means. If you believe the in the standard model of cosmology, then the DM should be somewhere around the galaxies. But it's of course not uniformly distributed, so a DM engine would work (if at all...) only in the periphery of galaxies. It's already impossible to get there...
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    One reply to Pacome, though the discussion exceeds by far the relevance of the topic already. Baryonic DM is strictly limited by cosomology, if one believes in these models, of course. Anyway, even though most DM is cold, we are constantly bombarded by some DM particles that come together with cosmic radiation, solar wind etc. etc. If DM easily interacted with normal matter, we would have found it long ago. In the paper they consider DM as neutralinos, which are neither baryonic nor strongly or electromagnetically interacting.
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    well then I agree, how the fu.. they want to collect them !!!
LeopoldS

Operation Socialist: How GCHQ Spies Hacked Belgium's Largest Telco - 4 views

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    interesting story with many juicy details on how they proceed ... (similarly interesting nickname for the "operation" chosen by our british friends) "The spies used the IP addresses they had associated with the engineers as search terms to sift through their surveillance troves, and were quickly able to find what they needed to confirm the employees' identities and target them individually with malware. The confirmation came in the form of Google, Yahoo, and LinkedIn "cookies," tiny unique files that are automatically placed on computers to identify and sometimes track people browsing the Internet, often for advertising purposes. GCHQ maintains a huge repository named MUTANT BROTH that stores billions of these intercepted cookies, which it uses to correlate with IP addresses to determine the identity of a person. GCHQ refers to cookies internally as "target detection identifiers." Top-secret GCHQ documents name three male Belgacom engineers who were identified as targets to attack. The Intercept has confirmed the identities of the men, and contacted each of them prior to the publication of this story; all three declined comment and requested that their identities not be disclosed. GCHQ monitored the browsing habits of the engineers, and geared up to enter the most important and sensitive phase of the secret operation. The agency planned to perform a so-called "Quantum Insert" attack, which involves redirecting people targeted for surveillance to a malicious website that infects their computers with malware at a lightning pace. In this case, the documents indicate that GCHQ set up a malicious page that looked like LinkedIn to trick the Belgacom engineers. (The NSA also uses Quantum Inserts to target people, as The Intercept has previously reported.) A GCHQ document reviewing operations conducted between January and March 2011 noted that the hack on Belgacom was successful, and stated that the agency had obtained access to the company's
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    I knew I wasn't using TOR often enough...
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    Cool! It seems that after all it is best to restrict employees' internet access only to work-critical areas... @Paul TOR works on network level, so it would not help here much as cookies (application level) were exploited.
Christophe Praz

Scientific method: Defend the integrity of physics - 2 views

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    Interesting article about theoretical physics theories vs. experimental verification. Can we state that a theory can be so good that its existence supplants the need for data and testing ? If a theory is proved to be untestable experimentally, can we still say that it is a scientific theory ? (not in my opinion)
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    There is an interesting approach by Feynman that it does not make sense to describe something of which we cannot measure the consequences. So a theory that is so removed from experiment that it cannot be backed by it is pointless and of no consequence. It is a bit as with the statement "if a tree falls in the forrest and nobody is there to hear it, does it make a sound?". We would typically extrapolate to say that it does make a sound. But actually nobody knows - you would have to take some kind of measurement. But even more fundamentally it does not make any difference! For all intents and purposes there is no point in forcing a prediction that you cannot measure and that therefore has noto reflect an event in your world.
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    "Mathematics is the model of the universe, not the other way round" - M. R.
Thijs Versloot

Scientists have developed a material so dark that you can't see it... - 7 views

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    A British company has produced a "strange, alien" material so black that it absorbs all but 0.035 per cent of visual light, setting a new world record. To stare at the "super black" coating made of carbon nanotubes - each 10,000 times thinner than a human hair - is an odd experience.
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    Finally! Nowadays blacks were always too bright for my taste...
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    "No matter how fast light travels, it finds the darkness has always got there first, and is waiting for it." I will keep waiting for my darkness-emitting diodes...
jcunha

'Superman memory crystal' that could store 360TB of data forever | ExtremeTech - 0 views

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    A new so called 5D data storage that could potentially survive for billions of years. The research consists of nanostructured glass that can record digital data in five dimensions using femtosecond laser writing.
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    Very scarce scientific info available.. I'm very curious to see a bit more in future. From https://spie.org/PWL/conferencedetails/laser-micro-nanoprocessing I made a back of envelop calc: for 20 nm spaced, each laser spot in 5D encryption encodes 3 bits (it seemed to me) written in 3 planes, to obtain the claimed 360TB disk one needs very roughly 6000mm2, which does not complain with the dimensions shown in video. Only with larger number of planes (order of magnitude higher) it could be.. Also, at current commercial trends NAND Flash and HDD allow for 1000 Gb/in2. This means a 360 TB could hypothetically fit in 1800mm2.
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    I had the same issue with the numbers when I saw the announcement a few days back (https://www.southampton.ac.uk/news/2016/02/5d-data-storage-update.page). It doesn't seem to add up. Plus, the examples they show are super low amounts of data (the bible probably fits on a few 1.44 MB floppy disk). As for the comparison with NAND and HDD, I think the main argument for their crystal is that it is supposedly more durable. HDDs are chronically bad at long term storage, and also NAND as far as I know needs to be refreshed frequently.
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    Yes Alex, indeed, the durability is the point I think they highlight and focus on (besides the fact the abstract says something as the extrapolated decay time being comparable to the age of the Universe..). Indeed memories face problems with retention time. Most of the disks retain the information up to 10 years. When enterprises want to store data for longer times than this they use... yeah, magnetic tapes :-). Check a interesting article about magnetic tape market revival here http://www.information-age.com/technology/data-centre-and-it-infrastructure/123458854/rise-fall-and-re-rise-magnetic-tape I compared for fun, to have one idea of what we were talking about. I am also very curious so see the writing and reading times in this new memory :)
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    But how can glass store the information so long? Glass is not even solid?!
Marion Nachon

Observation : this month, four planets aligned in the early morning sky. - 9 views

This month, some 30 minutes before the sunrise, look to the East, and if the sky is not too cloudy you will see Mercure, Venus, Mars and Jupiter very close, so close that it will be possible to hid...

http:__ciencia.nasa.gov_ciencias-especiales_09may_morningplanets_ space

started by Marion Nachon on 11 May 11 no follow-up yet
LeopoldS liked it
LeopoldS

Natural and anthropogenic variations in methane sources during the past two millennia :... - 0 views

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    once more ... the Romans did it already 2000 years ago! this time: burning so much wood that they increased the methane level in a way we can still measure it in ice cores ...
santecarloni

BBC News - Atomic bond types discernible in single-molecule images - 0 views

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    A pioneering team from IBM in Zurich has published single-molecule images so detailed that the type of atomic bonds between their atoms can be discerned.
LeopoldS

[1305.3913] Indication of anomalous heat energy production in a reactor device - 5 views

shared by LeopoldS on 23 May 13 - No Cached
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    looks like some backwind for all the cold fusion believers ...
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    Actually Sante and me just reviewed their paper. Although (some of) the scientists in the paper seem to have good track records their experimental techniques are by far not the best to determine the excess amount of energy produced. Even though their methods may introduce fairly large errors they would not be able to negate the cited power output - so they either are super-sloppy (i.e. they lie) or there is TRULY new physics involved... A big problem is that they are basically verifying somebody else's experiment - however because this guy is paranoid he does not tell them exactly what he did. In fact they went to his lab and used a setup that HE put together. All they do is do a measurement on it and it seems like they try to be thorough. There is quite a chance that the guy behind it all (Rossi) is setting them up - personally I would think >95%. However, the implications of this being new physics are so big that I think further research should be conducted.
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    I just answered something very similar to Franco, except the conclusions: I don't think that there is a good reason for us or anybody else in ESA to get involved at this stage.
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    I agree - if this device would work it there would be other interest groups (like the energy sector) with a much more concrete stake in the technology.
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.
Annalisa Riccardi

Frozen Frog :) - 5 views

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    Icing organs... Why scientists are so near and yet so far from being able to cryopreserve organs
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    Nice overview!
santecarloni

Amateur planet hunters find a world with a four star rating | Bad Astronomy | Discover ... - 4 views

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    One more reason why we should be much more open about all these EO data we have .... The two citizen scientists, Kian Jek and Robert Gagliano, are listed as authors on the scientific paper recently published. I love this: the digital nature of these data make it far, far easier to analyze the science than it was in the past, and also easier to get the data out to people. Because of this, we have an explosive growth in these kinds of projects. Planet Hunters is great, but then so is Galaxy Zoo, Moon Mappers, Ice Hunters, and so many others. You can find several of these collected at the CosmoQuest website.
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    Wiktor is also collecting these science games in the ACT-wiki. You should have a look at: http://sophia.estec.esa.int/actwiki/index.php/On-line_Games_4_Science
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