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pacome delva

"Quantum trampoline" measures gravity - 2 views

  • Physicists in France have come up with a new way of using bouncing ultracold atoms to measure the acceleration due to gravity. The technique involves firing vertical laser pulses at a collection of free-falling atoms, which bounces some atoms higher than others. When the atoms recombine at the centre of the experiment, they create an interference pattern that reveals that g is 9.809 m/s2 – just as expected for their Paris lab.
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    That's the lab I worked...
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    just being cinical ... but did not we know that g = 9.809 in Paris? I can also create a complex measurement procedure that will held pi = 3.1415, just as expected!!!
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    well, sure... the interest of such gravimeter is to be absolute, and for now slightly more accurate than the other type of absolute gravimeter which uses retroreflector and interferometry ( http://en.wikipedia.org/wiki/Gravimeter ). While the latter ones reached their limit in term of sensitivity, the atomic ones can be enhanced in many ways (using cooler atoms, better optics, etc...)
Francesco Biscani

STLport: An Interview with A. Stepanov - 2 views

  • Generic programming is a programming method that is based in finding the most abstract representations of efficient algorithms.
  • I spent several months programming in Java.
  • for the first time in my life programming in a new language did not bring me new insights
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  • it has no intellectual value whatsoever
  • Java is clearly an example of a money oriented programming (MOP).
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    One of the authors of the STL (C++'s Standard Template Library) explains generic programming and slams Java.
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    "Java is clearly an example of a money oriented programming (MOP)." Exactly. And for the industry it's the money that matters. Whatever mathematicians think about it.
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    It is actually a good thing that it is "MOP" (even though I do not agree with this term): that is what makes it inter-operable, light and easy to learn. There is no point in writing fancy codes, if it does not bring anything to the end-user, but only for geeks to discuss incomprehensible things in forums. Anyway, I am pretty sure we can find a Java guy slamming C++ ;)
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    Personally, I never understood what the point of Java is, given that: 1) I do not know of any developer (maybe Marek?) that uses it for intellectual pleasure/curiosity/fun whatever, given the possibility of choice - this to me speaks loudly on the objective qualities of the language more than any industrial-corporate marketing bullshit (for the record, I argue that Python is more interoperable, lighter and easier to learn than Java - which is why, e.g., Google is using it heavily); 2) I have used a software developed in Java maybe a total of 5 times on any computer/laptop I owned over 15 years. I cannot name of one single Java project that I find necessary or even useful; for my usage of computers, Java could disappear overnight without even noticing. Then of course one can argue as much as one wants about the "industry choosing Java", to which I would counterargue with examples of industry doing stupid things and making absurd choices. But I suppose it would be a kind of pointless discussion, so I'll just stop here :)
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    "At Google, python is one of the 3 "official languages" alongside with C++ and Java". Java runs everywhere (the byte code itself) that is I think the only reason it became famous. Python, I guess, is more heavy if it were to run on your web browser! I think every language has its pros and cons, but I agree Java is not the answer to everything... Java is used in MATLAB, some web applications, mobile phones apps, ... I would be a bit in trouble if it were to disappear today :(
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    I personally do not believe in interoperability :)
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    Well, I bet you'd notice an overnight disappearance of java, because half of the internet would vanish... J2EE technologies are just omnipresent there... I'd rather not even *think* about developing a web application/webservice/web-whatever in standard C++... is it actually possible?? Perhaps with some weird Microsoft solutions... I bet your bank online services are written in Java. Certainly not in PHP+MySQL :) Industry has chosen Java not because of industrial-corporate marketing bullshit, but because of economics... it enables you develop robustly, reliably, error-prone, modular, well integrated etc... software. And the costs? Well, using java technologies you can set-up enterprise-quality web application servers, get a fully featured development environment (which is better than ANY C/C++/whatever development environment I've EVER seen) at the cost of exactly 0 (zero!) USD/GBP/EUR... Since many years now, the central issue in software development is not implementing algorithms, it's building applications. And that's where Java outperforms many other technologies. The final remark, because I may be mistakenly taken for an apostle of Java or something... I love the idea of generic programming, C++ is my favourite programming language (and I used to read Stroustroup before sleep), at leisure time I write programs in Python... But if I were to start a software development company, then, apart from some very niche applications like computer games, it most probably would use Java as main technology.
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    "I'd rather not even *think* about developing a web application/webservice/web-whatever in standard C++... is it actually possible?? Perhaps with some weird Microsoft solutions... I bet your bank online services are written in Java. Certainly not in PHP+MySQL :)" Doing in C++ would be awesomely crazy, I agree :) But as I see it there are lots of huge websites that operate on PHP, see for instance Facebook. For the banks and the enterprise market, as a general rule I tend to take with a grain of salt whatever spin comes out from them; in the end behind every corporate IT decision there is a little smurf just trying to survive and have the back covered :) As they used to say in the old times, "No one ever got fired for buying IBM". "Industry has chosen Java not because of industrial-corporate marketing bullshit, but because of economics... it enables you develop robustly, reliably, error-prone, modular, well integrated etc... software. And the costs? Well, using java technologies you can set-up enterprise-quality web application servers, get a fully featured development environment (which is better than ANY C/C++/whatever development environment I've EVER seen) at the cost of exactly 0 (zero!) USD/GBP/EUR... Since many years now, the central issue in software development is not implementing algorithms, it's building applications. And that's where Java outperforms many other technologies." Apart from the IDE considerations (on which I cannot comment, since I'm not a IDE user myself), I do not see how Java beats the competition in this regard (again, Python and the huge software ecosystem surrounding it). My impression is that Java's success is mostly due to Sun pushing it like there is no tomorrow and bundling it with their hardware business.
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    OK, I think there is a bit of everything, wrong and right, but you have to acknowledge that Python is not always the simplest. For info, Facebook uses Java (if you upload picture for instance), and PHP is very limited. So definitely, in company, engineers like you and me select the language, it is not a marketing or political thing. And in the case of fb, they come up with the conclusion that PHP, and Java don't do everything but complement each other. As you say Python as many things around, but it might be too much for simple applications. Otherwise, I would seriously be interested by a study of how to implement a Python-like system on-board spacecrafts and what are the advantages over mixing C, Ada and Java.
pacome delva

Synthetic Genome Brings New Life to Bacterium - 0 views

  • For 15 years, J. Craig Venter has chased a dream: to build a genome from scratch and use it to make synthetic life. Now, he and his team at the J. Craig Venter Institute (JCVI) in Rockville, Maryland, and San Diego, California, say they have realized that dream.
  • "One thing is sure," Boeke says. "Interesting creatures will be bubbling out of the Venter Institute's labs."
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    wow, a big step in genomics...!
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    But isn't it just yet another word abuse? From what I understand, they just synthesised a genome identical to the one of an existing bacteria... while undoubtedly nice work, this is *very* far from "creating life from scratch"... The fact that you are able to copy something, doesn't mean you understand how it works...
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    well of course we are far from engineering specific functions, and this is just a copy of a function that already existed. However it is quite impressive and the first time it is done. And the challenge here is not really to "copy" the ADN, but the fact that it works... in other words it is not because you copy the ADN identically that the phenotype (traduction of the ADN) will be the same, which is the case in this experiment.
Joris _

Video: Seagull Robot Takes Off And Flies On Its Own, Just Like the Real Thing | Popular... - 5 views

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    Awesome, they managed. (this is a different deal as the micro ones )
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    haha, just what they need in holland ;) anyway this is impressive !
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    really nice - must not be that easy to control, correct?
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    when we tried (http://cas.ensmp.fr/~petit/site-oiseau-np/main.htm good old time :) ) the kinematic and mechanics were the big issues.
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    this looks like a very nice project back in 2005 ...
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    Does it also attack people to capture their fish & chips like those beasts we have here in St. Ives?
LeopoldS

microsoft just bought GitHub .... - 5 views

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    microsoft just bought github ...
LeopoldS

Scientists test novel power system for space travel (w/ video) - 1 views

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    Less impressive than the headline, since they actually just tested their conversion system at suboptimal conditions on an existing reactor setup, but still since done within six month and with less than 1M€ ...
Dario Izzo

pongmuseum.com - and the ball was square... - 4 views

shared by Dario Izzo on 28 Nov 12 - Cached
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    1969 - Man on the moon, and videogames just born 2012 - Man still here and Diablo III out :)
LeopoldS

Volare robotics challenge, robot helpers for ISS competition by ESA | Robohub - 1 views

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    i just saw this on robohum when reading guidos astrodrone article ...
Dario Izzo

Climatologists are no Einsteins, says his successor | NJ.com - 2 views

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    I know at least of a few people who share this point of view :)
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    I think it is worth noting that Dyson's is not saying that climate change is an illusion - it is evident that a lot of CO2 is emitted into the atmosphere and hence something will change. His point is that we just don't know what will change and by how much and that (much) more experimental data is necessary to make predictive models.
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    On missing experimental work: just read in the news that condensation in cirrus clouds has been studied recently and that the models where incorrect as to what the significance of organic substances and soot is in cirrus cloud formation. http://www.sciencemag.org/content/early/2013/05/08/science.1234145
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.
Marcus Maertens

The Fold-and-Cut Problem (Erik Demaine) - 3 views

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    How many shapes can be obtained by folding a paper and applying just one straight cut? You'll be surprised...
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    "The theorem is that every pattern (plane graph) of straight-line cuts can be made by folding and one complete straight cut. Thus it is possible to make single polygons (possibly nonconvex), multiple disjoint polygons, nested polygons, adjoining polygons, and even floating line segments and points." - So the you can cut any assembly of polygons but not a single curved edge (with a finite number of folds (points don't count)): useless. :-P
Marcus Maertens

Gene switches make prairie voles fall in love : Nature News & Comment - 2 views

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    Is love just an epigenetic mechanism?
santecarloni

Galaxy's centre tastes of raspberries and smells of rum | Science | guardian.co.uk - 1 views

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    We just need some chocolate....
Dario Izzo

Xeon Phi Powers HPC Stampede | Go Parallel - 4 views

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    Just to point out we did indicate this is happening well in time .....
Marcus Maertens

MIT constructs synthetic analog computers inside living cells | ExtremeTech - 0 views

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    Just a small step till we can compute trajectories in our blood cells...
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    Really cool research. I think that the potential of analog computing has been neglected for quite a long time. Building the whole thing within a single cell makes it only more awesome.
Marcus Maertens

World's first telescopic contact lens gives you Superman-like vision | ExtremeTech - 1 views

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    Now we just need an x-ray mode and we are done.
LeopoldS

World's biggest geoengineering experiment 'violates' UN rules | Environment | guardian.... - 1 views

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    I am certain that this is just the first in a series - highlighting the big dilemma of geo engineering: it's so cheap to do ....
santecarloni

The Higgs, Boltzmann Brains, and Monkeys Typing Hamlet | The Crux | Discover Magazine - 7 views

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    good luck with this....
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    Nice article, actually! It summarizes in "human readable format" why and how too many cosmologists and string theorists just went bozo...
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    really ! this article should go for the ignobels ! http://arxiv.org/abs/0808.3778 I wonder which substance theorists are taking... I will avoid...! but really this is very preoccupating: "complex structures will occasionally emerge from the vacuum as quantum fluctuations, at a small but nonzero rate per unit spacetime volume. An intelligent observer, like a human, could be one such structure." Is this a new alternative to Darwinism...??? a support to creationism ?? How can a physicist can write such non-sense ?
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    and this is published in PRD !!!
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    In 1996 Sokal hoaxed sociologists with his famous nonsense text on political implications of quantum gravity. Can one play a similar game with "researchers" on Boltzmann brains, multiverses, string landscapes or similar? I doubt, this is just reality satire that can't be topped.
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    Poor Boltzmann ...
Dario Izzo

Bold title ..... - 3 views

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    I got a fever. And the only prescription is more cat faces! ...../\_/\ ...(=^_^) ..\\(___) The article sounds quite interesting, though. I think the idea of a "fake" agent that tries to trick the classifier while both co-evolve is nice as it allows the classifier to first cope with the lower order complexity of the problem. As the fake agent mimics the real agent better and better the classifier has time to add complexity to itself instead of trying to do it all at once. It would be interesting if this is later reflected in the neural nets structure, i.e. having core regions that deal with lower order approximation / classification and peripheral regions (added at a later stage) that deal with nuances as they become apparent. Also this approach will develop not just a classifier for agent behavior but at the same time a model of the same. The later may be useful in itself and might in same cases be the actual goal of the "researcher". I suspect, however, that the problem of producing / evolving the "fake agent" model might in most case be at least as hard as producing a working classifier...
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    This paper from 2014 seems discribe something pretty similar (except for not using physical robots, etc...): https://papers.nips.cc/paper/5423-generative-adversarial-nets.pdf
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    Yes, this IS basically adversarial learning. Except the generator part instead of being a neural net is some kind of swarm parametrization. I just love how they rebranded it, though. :))
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