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liquid cooled and running at 50Mhz

Sorry, but you can't really push the 741 far above maybe 10 kHz...

Thanks. But this is neither the Slashdot description nor the page linked from it. That page is referred by a link inside the linked page, which BTW I don't recall seeing yesterday (there was a link to the PDF version of the actual paper which I cannot find anymore). They might have updated that description.

Anyway, my original post was meant to make clear what wasn't clear and your reference is precisely reinforcing that impression, as far as having to go to the page linked by the page linked in the summary isn't precisely clear :)

Georges Lemaître. Apparently his being a priest led to some accusations that he was using science to promote Christian dogma.

Well, Muslim scholars pioneered quite a few advances in algebraic concepts.
http://www-history.mcs.st-andr...

We see similar structures right here on earth (e.g. a rough 5 sided figure)), just a big difference is there is a lot more stuff in the way and such weather is a lot more transient, not lasting very long.

Probably the laser will probably in a wavelength of light that clouds don't absorb. There are a few "infra-red windows" that can be used.
http://www.st-andrews.ac.uk/~bds2/ltsn/ljm/JAVA/SPECTRUM/details.html

Then they'll use TCP/IP adapted for space communication - modifying the protocol to handle time lag. That's more or less what it was like using the "Kermit" protocol with a 9600 or 19200 baud modem (~960 characters/second) - we used to "turbo boost" our connections by using large packets (1024 bytes). Even so, five packets could be sent down, in the time it took the other end to calculate the CRC's and send back the acknowledgement.

It's better than what they have now, so they won't complain.

Stuart Hameroff is an organizer of this conference, which I'm sure this research was timed for release just before. Stuart has long been an advocate of a theory he developed with Roger Penrose in which the microtubules are the brain's interface with the quantum.

Besides, exactly how many sites use webcams anyway?

Few, mostly because only Flash Player is capable of using them.

I can't say I've ever run across any, besides Gmail video chat of course, but then again I'm not into online sex chats.

Mostly I was thinking of things like Face of the Future, Chatroulette, and whatever else people will think up once they have the tools to connect a webcam to a server (again, with the end user's permission).

I'd like to add here that if enough places did exactly this

But it's not likely to happen because if a web site says "install Google Chrome Frame to view this site", end users behind IE are likely to just click away to a competitor's site.

I haven't heard of "Newgrounds"

It's like YouTube, except for SWF vector animations and SWF games instead of raster video. Please read Wikipedia's description of the site and tell me something similar that you have heard of.

Electricity isn't required "8 hours a day", and the grid required for current solar panels to supply an entire country's worth of power...

So you like most others ignored other energy sources. I mentioned two that don't depend on the sun shining, geothermal and wind. Geothermal is steady and reliable, and the wind is always blowing somewhere.

in the US, you have a lot of empty space, but over here in the UK we don't actually have room for all the of required panels.

So use other sources. At the beginning of 2011 the UK received over 5.2 gigawatts of wind power making it the eighth largest wind energy producer. The UK's wind potential is much higher. The University of Strathclyde says "it is theoretically possible to obtain more than 1000TWh of electricity each year from the wind." The University of St Andrews in Scotland says there's a lot of potential for geothermal. The Scottish National Minewater Potential Study [pdf] details some of that potential.

Falcon

The wavelengths at which different isotopes absorb light are slightly different (Hyperfine structure), so if you tune the wavelength of your laser just right, you can use radiation pressure rather than the (typically weaker) optical gradient force to at least identify different isotopes. (I work in cold atom physics and was just doing this in the lab with Rubidium 85 and 87).

However, the radiation pressure on an atom is limited by the atom, whereas the optical gradient force is limited by the power of your laser. At room temperature, you can't use radiation pressure to separate Rb 85 and 87. There is considerably more freedom to engineer the forces experienced by the particle if you use the optical gradient forces and tricks, like Bessel beams, or more generally SLMs, which are essentially computer-programmable holograms. See, for example, the excellent experimental work of the Dholakia and Padgett groups.

but Google is failing me as to its name.

I think you're talking about Face of the Future.

The ability to discover simple to control systems that operate as analogues to more advanced physics is wonderful and not some fake trick as some comment posters suggest.

Check out this page where the kitchen sink phenomenon is shown as well as another analogue for an event horizon, the "fish in the stream" analogue. (Where water flow is faster than a fish's top speed, a fish will hit a point of no return.) Found by googling for: physics analogue kitchen.

This page has some interesting explanations and also mentions there are other analogues that for example suggest answers to the still open question of what happens at planck lengths where space is expected to become grainy or net-like.

There is another page that describes another use of the same circular hydraulic jump in the kitchen sink, saying that it is a three-way analogue: "The connection between ocean bores, stellar gases, and the swirl of water in the kitchen sink is a splendid example of a three-way physical model." So with white holes brought in maybe this is a four-way analogue now. This page is quite a fun read and describes in detail why the hydraulic jump appears. It also describes how this is like the shock wave caused by the upwelling of gas from a star's surface meeting gas that is falling back onto the sun.

Though in the scenario GP seems to be talking about (multihoming a SOHO network), BGP based multihoming is a nonstarter.

ILNP, on the other hand, looks interesting.

TFA doesn't seem quite a novelty - even more, the linked article contains some nice layman-term explanations, including how to create a white-hole in the kitchen sink; this may help you to guess an answer on what could happen when you shut close the tap (errr... what happens when the horizon collapses).

For those who did not RTFA or article comments, more interesting fiber optic black holes (and pictures!) : http://www.st-andrews.ac.uk/~ulf/fibre.html

I've seen your sig on a bathroom stall wall before. Granted, it was the the top uni in Scotland. Damned pretentious bastards.

These are the words of Jean Baptiste Joseph Fourier in 1793 as he joined his local Revolutionary Committee:

"As the natural ideas of equality developed it was possible to conceive the sublime hope of establishing among us a free government exempt from kings and priests, and to free from this double yoke the long-usurped soil of Europe. I readily became enamoured of this cause, in my opinion the greatest and most beautiful which any nation has ever undertaken."

http://www-history.mcs.st-andrews.ac.uk/Biographie s/Fourier.html

D'Arcy_Thompson's bio.

Excepts from his book "On Growth and Form"

OK, so the Casimir effect is simply a property of the quantum vacuum. It is a resut of there being nothing. These "reseachers" propose to replace that vacuum with a material that was carefully chosen for its electromagnetic properties. Hey, that's all fine and dandy but then your so-called "levitating" object is simply an object that is sitting on top of a crystal of some sort.

With all due respect, but that ain't levitation. That's an object sitting on another object. A feat that I'm sure I have accomplished in my own life before -- and I didn't even need an object of negative index of refraction to do it.

A humorous page about these British scientists' work by St Andrews physics Professor Leonhardt explains their work on Casimir "levitation".

Try checking out the University website - it had much more information about the science of the discovery:

http://www.st-andrews.ac.uk/~ulf/levitation.html

Pity they have a photo of Syndrome and his Zero-Point Energy device as an example at the top. Doesn't help anyone to take them seriously surely.

Vinyl isn't as good as you'd think: at theoretical best only slightly better than CDs, in reality quite a bit worse. Here's why

is a Best Buy or a Barnes 'n Noble. you're going to need to know the tools and procedures of open source development before you can get anything done or changes submitted.

0. Install an Open Source operating system with development tools, such as [Net,Free,Open]BSD or Linux
1. Learn CVS [http://cvsbook.red-bean.com/, http://www.cs.kent.ac.uk/systems/cvs-howto.html%5D .
2. Learn the basics of the GNU C Compiler [http://www.faqs.org/docs/learnc/].
3. Learn Automake, Autoconf and Libtool [http://sources.redhat.com/autobook/autobook/autob ook.html, http://autotoolset.sourceforge.net/tutorial.html, http://www.amazon.com/Autoconf-Automake-Libtool-Ga ry-Vaughan/dp/1578701902, http://www.st-andrews.ac.uk/~iam/docs/tutorial.htm l%5D.
4. Download a tarball of some source code and compile it, learn how to edit Makefiles, etc.
5. Check out the source code of the same application from CVS, mess around with it.

As I said, others have done it. I'm sure there are many variations in recording/playback chains.

Why would harmonics be lost in the transfer to CD? You mean, just due to the Nyquist cutoff? Vinyl's frequency response is typically quoted as 15 kHz. And the human ear is hardly perfect.

http://www.st-andrews.ac.uk/~jcgl/Scots_Guide/iand m/part12/page2.html

You can probably guess that I hail from the Realist school of audio. I like vinyl because it's fun; I don't think it's inherently superior to CD.

It is interesting to note that one of the oldest civilizations we know that used math, the Babylonians, used base 60. That gives easy dividing by 2, 3, 4(!), 5 and 6. Their system of dividing a day into 24 hours of 60 minutes of 60 seconds survives to this day.

They were pretty advanced, being able to solve some 3rd degree polynomials, and with reasonably advanced architecture and commerce. See e.g. http://www-history.mcs.st-andrews.ac.uk/HistTopics /Babylonian_mathematics.html. Not bad for 5000 years ago.

I think you're confusing reality and theory. And in reality, analog isn't infinite precision. So the medium does matter. (Or can I use a theoretical, infinite bits, infinite sample rate digital data stream for the comparisons?)
Real world digital does a better job than real world analog of faithfully reproducing the signal. This can be calculated. It's a fact. Get over it. You've sunk a boat load o'cash into a technically inferior system. Try looking into signal theory, it's all well understood, and the basis for quite a bit of modern techncal goodness, no need to go into "analog's a better sample than a digital sample" pseudoscience.
Do you put green pen round your CDs, any any chance???
So, digital is better at "HiFi" (hint - that's "fidelity" in there) than analog. The crunch is: that box you use to listen to music, is it's job to give the most accurate rendition of the signal it can, or the one that's nicest to listen to? Vinyl may well seem to sound better, subjectively. But don't be mislead that analog is technically better than digital - it ain't.

Check out this page of photographs of Albert Einstein. When he developed his theory of relativity, he was in his twenties, and you will see that in the picture that shows him as a young man, he is dressed conventionally. He worked in a patent office at the time. His 'mad scientist' persona coincided with the ever-increasing media profile that came with the immense fame that followed his discoveries.

Here's the link.

http://www-history.mcs.st-andrews.ac.uk/PictDispla y/Einstein.html

For those who think this device's use will somehow be limited to rioters, I want you to look up Victoria Snelgrove

She was killed by non-lethal technology (second hand shot from a pepperball gun to the temple) less than one year ago.

Technology always gets used for things other than what it was intended for. From people scratching on turntables, to aircraft, to video game music, to internet over cable, etc.

Those who suggested the emergence of "acceptable casualty rates" have the most foresight. That being said, this thing is pretty powerful. I wouldn't cry chicken little about it yet. The government doesn't get that scary that quickly. However, this is the kind of thing where we really ought to recognize that we can create any kind of technology we want to. Is this "heat ray" what we really want? What if we could instead, say, transport prepared food in minutes between here and other countries? You could feast on different food every night from around the world!

Probably one of the scarier things about this is it looks easy to build. Just a high-powered oscillator and Fresnel antenna (look closely at the pics). Now that the US has put the idea out there, I can imagine all kinds of people making their own...and forgetting to ask people to take off their glasses and remove their keys and pocket change and turn it off after five seconds.

And for those who might say 65 GHz oscillators are difficult, I thought they were too, until I just looked them up and found parts.

Remember, it feels like heat, because it IS heat.

And finally: "After her death , Boston Red Sox outfielder Trot Nixon said he would have traded back Game 7 Of The 2004 ALCS to have her back."

For the physics inclined, have a read here about skin effect in audio cables.

The basic idea is that electrons ride the outside of a conductor, not equally through its cross-section. The depth of the 'skin' depends on frequency. You might think that stranded cable would do better then, since there's more surface area, but because the strands aren't insulated they act as a single conductor, providing no skin-effect benefit. There is an exception, cables of 'Litz' construction, where each conductor is individually insulated, creating a virtual cable of effective diameter without skin effect.

My take-away from the linked article is that skin effect does have a slight effect on sound quality that can be measured and possibly perceived. Swinging back to the topic, Monster does make a Litz speaker cable, but it runs you $1500 per 3-foot cable - this isn't Best-Buy level Monster cable. A Google search on Litz at monstercable.com only provides two hits, both 3rd-party write-ups.

So to achieve top theoretical sound quality, assuming good connections, etc., you can buy thousands of dollars worth of top-quality Monster cables or cheap cables with fat conductors. If gauge and weight are far more important than cost, say on a Space Shuttle or similar, then dropping $10K on speaker cable might be worthwhile.

This all has me wondering of anybody here has used 10-gauge Romex as speaker cable.

I looked it up and you are indeed correct that the effects are negligible around audio frequencies. At 25KHz there is a drop of approximately .02dB and a propagation delay of -50nsec (high frequencies arrive before low frequencies), which are probably too subtle to be heard by humans.

Another interesting fact - due to the fact that braided wire still conducts between the braids, it is, for all practical purposes, equivalent to a solid wire with a slightly reduced cross section. Wire where each braid is insulated gives the most neutral characteristics, but again probably not audible.

A good explanation, as far as I can tell: http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/au dio/skineffect/page1.html

Jw

The same theme of building up tension or pressure behind a latch or spring (though not necessarily the exact same implementation as in the flytrap) is at work in the tongues of some frogs and lizards, in the legs of crickets and grasshoppers, and in click beetle flipping, to name a few.

We (Distributed Systems group at the University of St. Andrews) presented a paper at PGNet 2004, available at:

http://distsyst.dcs.st-andrews.ac.uk/btpaper.pdf

which shows (Figure 10) that 75% of BitTorrent users don't upload as much as they download, or put another way, the majority of the uploaded data comes from 25% of the users. I don't have time to work out just how much of the data each section is responsible for, but the numbers are interestingly close to the 80/20 rule.

I don't have time to run the numbers right now, but I wouldn't be too suprised to find that 20% of users uploaded 80% of the data...

It was in Ian Stewart's column "Mathematical Recreations" in Scientific American, pages 104-106, (1991). Stewart's article was based on a paper by the mathematician Kenneth Falconer. As far as I am aware the article by Ian Stewart is the first time a discussion about digital sundials appears in print.

The paper by Falconer is Sets with prescribed projections and Nikodym sets and was orginally published in the Proceeding of the London Mathematical Society 53 (1986), pages 48-64. The paper is concerned with a much more abstruse mathematical problem but, in everyday language, essentially describes a method to construct an object so that its shadows are any prescribed shape you wish at different times of the day. Of course, being a pure mathematics paper, the method given is completely impractical...

Cherokee and Arabic has three numbers. Not like 1, 2, 3; but, singular, dual, and plural.

But isn't the 1, 2, 3 numbering system of Arabic origin (or rather, Indian and Arabic origin)? Which would imply that even though they only have a limited number of words for numbers, they do have an understanding of mathematics that isn't bound to those three words.

Either way, very interesting post!

Happy to! And thanks for identifying yourself as someone with the background to understand.

For the math and theory underlying "skin effect", visit:

Skin Effect and Cable Impedance"

Then be sure to visit the Next Page to view the graphs of "Power Loss versus Frequency" and just as importantly, "Group Delay versus Frequency." You can clearly see the curve falling well within the audible range.

Happy to! And thanks for identifying yourself as someone with the background to understand.

For the math and theory underlying "skin effect", visit:

Skin Effect and Cable Impedance"

Then be sure to visit the Next Page to view the graphs of "Power Loss versus Frequency" and just as importantly, "Group Delay versus Frequency." You can clearly see the curve falling well within the audible range.

ph rocked :-) I used it quite a bit on the St Andrews university servers up until the end of 2002. looks like it's being phased out now though.

I feel I should mention that Isaac Newton (or even Issac Newton, whoever the hell he was) wasn't a PhD - such things didn't exist in the UK educational system in the 17th century. According to the MacTutor History of Mathematics Archive he got his BA in 1665 and incepted MA in 1668, at which point he was elected a college Fellow.

There have been higher doctorates (which, unlike in the US, are not always honorary awards) in the UK for centuries - doctorates in Divinity, Law, Medicine, and Music date back to mediaeval times, while the DSc and DLitt came in in the late 19th century. But the PhD, being a degree somewhere between the first postgraduate degree (studied at the beginning of one's specialist academic career) and the higher doctorates (typically awarded late in a career, on the basis of a substantial published research record), is less than a century old in the UK.

The PhD originated in Germany sometime in the 16th century, migrated to the US sometime in the 19th century (I think) and was introduced in the UK (to some initial scepticism) in the early 20th century.

These days, it's pretty much impossible to get anywhere in (British) academia without a PhD, but that's only really been the case in the last thirty years. In Newton's day (and this seems to have been true at Oxford and Cambridge until the mid-20th century) things were less rigidly qualification-focused. Being elected a Fellow of a college was the important thing.

A few years later, he was appointed Lucasian Professor of Mathematics - a post held currently by Stephen Hawking, and at various other times by Airy, Babbage, Stokes and Dirac.

More importantly, though, Newton was a Fellow of the Royal Society which pretty much beats any other academic honour short of a Nobel Prize or a Fields Medal.

nicholas

http://bowmore.dcs.st-andrews.ac.uk/rpms/ contains source and binary RPMs. The directory should not be accessible outside the .ac.uk domain, as I don't have the bandwidth to take a /.ing. Even if I've messed up the configuration, please do not try to download the RPMs. PLEASE

Also please note, these are barely tested. I patched, compiled, installed and ran the server/client, but haven't had time to do much more. People may want to wait until the official RedHat RPMs.

If someone wants to set up a mirror, post under here and I'll work something out.

PVC is a Polymer. This means its molecules have been grown by joining together lots of smaller molecules. The results of this polymerization process will depend upon the details of the process. The average molecular weights of the polymer chains which are formed can range from a few tens of hydrogen atom masses to hundreds of thousands. As a result, the PVC molecules are much larger than carbon atoms. This has the effect of producing a material which is 'lumpy' with a typical quantisation size far bigger than a carbon atom. As a result, the value for we should have used for the above expressions is hundreds of times larger than 0.5 nm, producing a much smaller dynamic range. As an example, if we assume the molecules in LP Vinyl are 100 times larger than a carbon atom, then resulting dynamic range might be expected to fall by 40dB to around 70dB.

The purpose of the above example was to help us recognise that, since LPs are made from a collection of real molecules, the signals they hold must be quantised. Fortunately for the LP this usually isn't obvious. The underlying signal quantisation is usually masked by various effects.

Skin effect is absolutely negligible at 60 Hz, in other words, skin depth is quite big in that freq range. And it's not real skin, OK? Descriptions here and here..

Paul Dirac wed Relativity and Quantum Mechanics long ago. It's where we get the proof of spin and anti-particles.

The old saw about "You're good at chess? Oh, you must be good at maths" has some logical background to it. Emanuel Lasker, World Chess Champion between 1894 and 1921, was also a world-class mathematician, doing original research in his chosen field under Hilbert.

(Some confirmation on the Agdestein story is also available, if you're interested.)

I am also led to understand that some of the lesser British chess GMs make more money from poker than they do from chess.

I would suggest a movie on Erdos or about Ramanujan.

And Kevin Spacey to play the first. And Ben Kingsley the second. He played Gandhi, after all...

I would suggest a movie on Erdos or about Ramanujan.

And Kevin Spacey to play the first. And Ben Kingsley the second. He played Gandhi, after all...

An online biography by J J O'Connor and E F Robertson covers some aspects left out of the autobiography on the Nobel site. The autobiography is interesting, though, for the way he expresses things.

Fermat. His last theorem was scribbled in the margin of a book, without an accompanying proof.

Stephen Smale is a _very_ eminent mathematician. A fields medal winner. He proved the poincare conjecture for dimensions greater than 4.

Do you mean the Steve Smale from Berkeley who won a Fields Medal?

smale bio

I heard him speak at MIT, and read a paper of his that was published in the Bulletin of the American Mathematical Society... On the Mathematical Foundations of Machine Learning, with Felipe Cucker I think. That was published in Oct. 2001, which qualifies as within the last 5 years, right?

Imagine for a minute that you don't know what problem you want to solve yet. You know that that you want to apply a Galerkin Finite Element Method (for instance, though this particular method isn't required) to a whole class of problems on unstructured grids on a whole class of distributed and shared memory parallel computers. Imagine that you want your user base to be able to specify their equations like they would in LaTeX or some other markup language. Now try imagining that you have only FORTRAN77. Not a pretty picture. We're in the process of completing a rewrite of major sections of our parallel code to do exactly this. Our code started out (7 years ago) as an extremely efficient parallel (3D) C/F77 code for Navier-Stokes + Heat Transfer and is quickly growing into a multi-purpose, multi-physics code written largely in C++.* We extract considerable advantage form C++'s ability to hide implemenations so that as long as interfaces don't change the guts can. We also make good use of the ability to run code before main() in order to register the exisitence of routines (hash tables are your friend). If the routine isn't there you can't call it, but the code still compiles and runs otherwise. We also make use of base class/derived class relationships and polymorphism to allow, for instance, one base mesh class for the rest of the code to interact with, but with two separate derived classes: one to generate meshes internally, and one to read meshes from other programs. Etc., etc. I'm not sure our website can take the /.'ing, but you can look here for some hints. * I say largely b/c there's a few struct's still left over from the code's C days, but all the F77 is gone. There are still calls to assembly coded (vendor supplied) BLAS routines, though.