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1GB of Google Drive Storage Now Costs Only $0.02 Per Month

cb123 Why do you think $.02*12/year/GB is cheap? (335 comments)

A 4TB drive is under 200 USD from several vendors. That is only $.05/GB. So, at 0.24/yr. This is 5..10X more expensive than commercial off the shelf home drive space assuming you have to buy a new drive every 1-2 years. That time figure is pretty conservative.

So, yeah, you maybe cloud storage gives you some replication, and the syncing of that replication costs some amount of money for bandwidth. How much extra that reliability costs really depends on the data dynamics, though and isn't as easy to estimate.

Also, 5..10X more is just about the ratio of SSD storage to magnetic disks. SSD is considered "relatively expensive storage" by most people I know.

about 6 months ago
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Mathematicians Extend Einstein's Special Relativity Beyond Speed of Light

cb123 Re:imaginary mass (381 comments)

Whoops - that should have been "without using *imaginary* mass".

about 2 years ago
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Mathematicians Extend Einstein's Special Relativity Beyond Speed of Light

cb123 Re:imaginary mass (381 comments)

If you just read the abstract to TFA you can see that the claim here is less novelty than the press release makes it sound like (the press overplays things - SHOCKER! ;-). They are really only presenting an alternate derivation without using mass of long-known results related to tachyonic physics and virtual particles and so forth.

Now, I am personally a bit dubious this is the first time the alternate derivation has been done, but I havne't read their particular approach. One would hope any reviewers assigned to the paper would have done reasonable due diligence/homework about the particulars (though sometimes that hope is in vain).

about 2 years ago
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Australian Study Backs Major Assumption of Cosmology

cb123 Visualizing The Scale (94 comments)

Most comments seem to be vying for most funny, but if you do happen to care about visualizing the scale, the distance to our closest full-sized galactic neighbor, the Andromeda Galaxy is 2.5 Mly. That is 1% of the homogeneity scale cited by the article. So, they are saying that things seem smooth averaged over scales merely 100 times bigger than the distance to the nearest extra-galactic clump which is sized comparably to The Milky Way. That's actually pretty smooth, in context.

about 2 years ago
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Goodbye, IQ Tests: Brain Imaging Predicts Intelligence Levels

cb123 Can it beat IQ if it's calibrated by IQ tests? (213 comments)

The press release doesn't cover that, nor the abstract and the rest of TFA is behind a paywall.

In case the one-liner in the subject isn't verbose enough the issue is "what is being measured". One needs some kind of gold standard. "Intelligence" is a slipperly enough of a concept that in practice it tends to be "defined by" some kind of measurement scheme. This new measurement scheme has to be calibrated by some existing one -- i.e. these measurements explain intelligence as independently assessed by some other extant measurement scheme.

Unless they get a lot better at correlating than 20%-ish then either they represent a refutation of those existing schemes (which requires some other compelling argument) or they are dramatically inferior, but some new enough approach to be "publishable". The latter is probably all the research article is about. So, don't get your hopes up on "pinning down the slippery". If you are already uncomfortable with IQ tests as assessments then you probably won't accept any calibration of the new technique and thus view it even more skeptically than the existing techniques.

about 2 years ago
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Why Were So Many "Crazy" Higgs Boson Stories Published?

cb123 LHC Expense-"God" Marketing-Silliness++ (291 comments)

Much of what is being said here is correct. Since the cancellation of the USA's SSC in the early 90s (a device that would have found the Higgs 15 years or so sooner), big science physics projects have had a hard go of things. Of course book publishers also will pounce on a catchy God particle marketing gimmick. Physicists will privately grimace even more at such over-hyping of the significance, but the difficulty of funding makes them shy away from outright rebuttal. The same people that are most "expert" in the domain have a direct interest in the domain seeming "interesting" to the ordinary folk who have to pay for it.

The Higgs mechanism only generates masses for the W and Z *gauge bosons*, not masses for quarks or leptons (see any good Wikipedia page) and certainly not "all matter" which is what a lot of the *officially* popular pieces indicate through inappropriate brevity. Without a Higgs-like particle the gauge bosons for the weak force ought to be massless like photons, but there was never, ever any problem with fermions like quarks and leptons having mass. Now, without W,Z,Higgs electroweak interactions would be very different, but it is almost totally insane to attribute everyday "mass" to the Higgs alone. Indeed, 99% of "everyday mass" comes from the binding energy of the strong force inside of nucleons, for example, not even the *rest* masses of quarks and electrons. "God particle" was never remotely appropriate. Various ideas about anti-gravity and the like are completely off track. It's important to be sure, but blown out of proportion (almost) beyond belief.

This all leads to "what bad analogies come next" in two to three decades when people want to fund (and promote) the Next Big Accelerator (NBA). The discoveries anticipated may have to do with supersymmetric partners. Could that lead to Jesus and Lucifer "offspring of God particle" or "wars in heaven" BS analogies or perhaps equally poor religion backlashes to already nutty analogies objecting to new pantheons or whatnot? Beats me. It seems likely that even allowing for global economic growth the "N.B.A." will be an even bigger fractional expense and so drive even greater craziness. Steel yourselves!

more than 2 years ago
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Citation Map Shows Top Science Cities

cb123 Re:misleading metrics (167 comments)

I actually was thinking of "what city would I like to live in". :-) You are correct that not all "capita"s are equally relevant and probably a total of grad students plus professors is a better denominator. Less refined census data than that is easier to come by, though. I do think that bigger cities support more schools and/or bigger graduate departments, other things being equal. So, in a vague statistical correlation sense just bulk census data gets you part of the way there.

If the real question is "what university would I like to be near" then a city is also the wrong aggregation unit, so not only the normalization but also the aggregation should change. I believe per university/per student or per professor/group output is what most academics would like to know for bragging rights or even funding priority reasons, but they usually make such evaluations themselves on a per department basis.

more than 3 years ago
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Citation Map Shows Top Science Cities

cb123 Re:misleading metrics (167 comments)

If you read the paper or click on the maps you will actually see that they DO NOT CORRECT for local population density. So, the metric in question is absolute rather than "per capita" productivity. This doesn't entirely invalidate it, but it calls into question how you would verbalize or interpret the results.

I mean, if 8 of the top 10 cities for science *by any metric* are also 8 of the top 10 cities by population you have said something less interesting. These cities are already top cities for "being" at all. :-)

It would be far more interesting to normalize in a per capita sense. There are clearly some major outliers in that sense scrolling around on the map. Vancouver lept out at me, but I'm sure others could find them as well. Now, wouldn't it be nice if the fancy visualization researchers helped us along in that task? :-)

more than 3 years ago
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Gosper's Algorithm Meets Wall Street Formulas

cb123 Re:The actual Deal, If anyone cares (124 comments)

I don't believe you understand the situation or my argument. It's not nearly as strong as P=NP or not. There could be non-hypergeometric family simplifications that do better than the Dai linear sums, and there can be other numerical methods that also do better (and there are for some kinds of options). This new paper just shows that one possible approach to simplify a formula won't work - a formula-to-be-improved already only compelling because Dai et al compare it to naive, strawmen alternatives they found in a textbook, not actual competitive methods available in the options pricing literature. So, it's not a paper to be rejected, but it really doesn't change the world much. It says, "don't look *here* for a way to simplify that other non-optimal approach".

more than 3 years ago
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Gosper's Algorithm Meets Wall Street Formulas

cb123 The actual Deal, If anyone cares (124 comments)

The naive CRR (Cox, Ross, Rubinstein) method for pricing options is O(n^2) where n is the number of levels in a recombinant binomial pricing lattice. That is, a lattice like a binary tree, but where you have cross links connecting nodes. The naive approach requires visiting each one of these nodes and hence O(n^2) and the error of the produced option goes down only proportional to the node spacing. For at least 15 years this problem has been converted to "linear time" (really the important relation is between the price error and the CPU time) by means of a variety of extrapolation methods (this began with Richardson extrapolation) using evaluation with two trees to get a much smaller error. There are in fact numerical methods that for special options can do slightly better than this. Broadie 1996 is one reference. While pretty fast and very easy to understand, there are yet faster methods using adaptive mesh crank-nicolson PDE solvers that do a bit better. Just a couple of years ago, Dai, et al. published a paper showing how to get linear time an entirely different approach involving combinatorial sums. This may have improved performance bounds for some exotic options, but did NOT do much for improving real-world implemented algorithmic performance of pricing the European and American options that are so commonly traded on exchanges, in the US and worldwide. So, at least for the most important class of options Dai et al was kind of a snoozer. The paper referenced in the summary above is entirely a follow-up paper to Dai, et al 2008. This new paper merely shows that there is no "short cut" in evaluating the relevant sums with hypergeometric functions, a kind of special function common in mathematical physics. So, in short, all this says is that the already "non fastest method" cannot be made faster by one numerical methods approach. It is certainly deserving of publication and dissemination, but changes the world not at all.

more than 3 years ago
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Bjarne Stroustrup Reflects On 25 Years of C++

cb123 Re:For some critical views of the language... (553 comments)

For some critical discussion of the "productivity", this recent thread might also be of interest. In the article in question Bjarne claims credit (dubiously IMO) for saving 'years of development time' on any complex project [ Google, DNA matching, etc. ] where people happened to use C++ instead of some alternative. http://www.reddit.com/r/programming/comments/cdncx/linus_about_c_productivity_again/?utm_source=web&utm_medium=twitter

more than 3 years ago
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Hawking Radiation Claimed Created In a Lab

cb123 Re:Double emission? (129 comments)

Yes, if Hawking's idea about black hole radiation is true, all gravity fields should radiate. Without even walking across the room you create thermal radiation at a fantastically small temperature no matter how small your ass is, just by virtue of your tiny gravitational field. There is no "sufficiently large gravity well" to generate the radiation, only sufficiently large to generate *measurable* radiation.

In the case of black holes, the radiation of stellar or galactic mass singularities is absolutely miniscule. Evaporation is only a "noticeable" process for very tiny black holes with the mass of an asteriod packed into the space of a proton.

As for what you can or cannot picture, that is your issue. I am just letting you know the basic phenomenon is much more broad and actually much more fundamental than a black hole event horizon membrane. The membrane and virtual pairs may begin (but not end) arguments and derivations or motivate theoretical preferences for resolving various issues, but it is misleading to call that imagined scenario the essence of the process. Physics teaching often suffers from "historical bias". Because some physicist first imagined things a particular way or convinced his peers a particular way, this is often the path used to motivate things to a popular audience. The truth is that after some thought and generalization it may be much less sensitive to the original motivating visual picture.

more than 3 years ago
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Hawking Radiation Claimed Created In a Lab

cb123 Re:I don't understand... (129 comments)

Virtual particles are really terms in a perturbation expansion that in some respects are terms similar to real particles and in other respects are not. For example, traveling backward in time is something they get to do, having negative energy, and so on. What they can and cannot do and why is context dependent and relies upon the actual formal derivations and properties of what is going on. So, as a "reasoning device" they fail most laymen, and in my opinion are not very intuition building.

So, to answer (1), yes -- just an analogy. (2) would be correct if the answer to (1) were "no", but it isn't. :-)

As I've referred to above, "capture" and "escape" of "virtual" particles is all a bunch of highly specific visualization related to a black hole or event horizon, but the actual result pertains to all accelerating reference frames and all spacetime curvature. Though Hawking himself might disagree with me, I find it pedagogically misleading to "explain" the possibility of this thermal radition in terms of processes only happening at a literal even horizon.

This is actually an interesting case of the strong principle of equivalence -- that gravity is locally indistinguishable from an accelerating frame of reference for all physical processes. (The weak principle of equiv is only about graviational forces, but the quantum vacuum is broader physics than that.) Specifically, you can derive Unruh radiation from quantum vacuum transformations *or* you get the same numerical temperature as starting from the idea that an accerelating reference frame "event horizon" is the same as a gravitational event horizon. I derived that latter in high school in the mid 80s, actually, to prove to myself that strong P of E held in this case. It's a relatively easy exercise in hyperbolic functions and basic calculus to compute the asymptotic trajectory of uniformly accelerating frame and back out the effective accerelation event horizon. Plug that in to Hawking's formula for a black hole and you get Unruh's result for acceleration. (They really call it Fulling-Davies-Unruh since it was done three times independently after the Hawking-Bekenstein results.)

I would agree with another responder here that not mentioning the thermal character of the radiation and words suggesting its monochromicity makes this particular result a little dubious, but I have not read the arXive article.

more than 3 years ago
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Hawking Radiation Claimed Created In a Lab

cb123 Re:I don't understand... (129 comments)

The process need not actually be distributed over space -- the escaping particle travels, yes, but the actual energy conversion happens when and where the escaping is first created.

Now, its creation is a quantum state transition which has a "magical" quality in the same way that, say, a photon escaping an atom's electron shell does. There is no extended energy transport process at all. The electron makes a quantum jump simultaneously with the photon field of the world gaining a new photon traveling away. Indeed, with visible light, the wavelength of the photon -- hundreds of nanometers -- can easily exceed the spatial scale of the atoms electron shell, usually a few nm. So, the photon kind of just "appears".

more than 3 years ago
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Hawking Radiation Claimed Created In a Lab

cb123 Re:I don't understand... (129 comments)

The responder has it right. You are missing that the virtual pair has no net energy initially and one escapes. So, the outside world is getting heavier and the black hole lighter - to conserve total system energy. You are thinking of the "virtual" counterpart as having mass, but it does not. It's "virtual".

As I mentioned above, one does not need a black hole for this -- all curved space should release thermal energy, though the rate is usually immeasurably small. Google Unruh effect and read about it in relation to the Sokolov-Ternov effect which has been observed since the 1970s. There is not perfect interpretational consensus about all this, though.

more than 3 years ago
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Hawking Radiation Claimed Created In a Lab

cb123 Re:Double emission? (129 comments)

Popular visualizations and even the notion of "virtual particles" do not allow very accurate reasoning with regards to Hawking radiation. In particular, the "promotion process" from "virtual" to "real" is just a crutch for proving something to all orders in perturbation theory. Shortly after Hawking-Bekenstein, Bill Unruh proved that simply being in a uniformly accelerated reference frame creates a perception of thermal background radiation coming from the background -- at a temperature equivalent to the pseudo-event horizon of the acceleration for the duration of the acceleration. You see, while if you move at a constant rate any photon will catch you just as quickly as if you were standing still (basic special relativity) if instead you accelerate forever, you asymptotically approach the speed of light, but there are photons far enough behind you that will never catch you. How far behind they need to be depends on how fast you are accelerating. So, every acceleration corresponds to a pseudo event horizon. As soon as one stops accelerating the photons can catch up to you. Unruh's result does *not* depend on the permanence of the horizon, but works for temporary accelerations. So, the horizon does not need to be "permanent" for the "promotion" to occur. A better way to think about Hawking radiation is any gravitation field (any curved space, that is) decaying via thermal radiation, or space itself providing some "resistance to acceleration" or intrinsic acceleration-only viscosity where the energy taken away from the acceleration is converted to thermal radiation. The image of a virtual pair around an event horizon is not, ultimately, how the result holds or is proven or even what the process is "about". It's more like an "inspiration to a derivation" than something to be taken so literally.

more than 3 years ago
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Go, Google's New Open Source Programming Language

cb123 10 seconds is just not fast; Sorry guys (831 comments)

I just used tcc to compile itself in *100 milliseconds*, some 100X faster than the Go advertisement. Does Go actually do 100X more work than a C compiler? Doutbful. It may be 100X faster than the insanity that has become gcc compiling itself, but it actually sounds pretty slow for what it does.

more than 4 years ago

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