Despite what other posters seem to think, this switch, if properly promoted, could get AOL more subscribers. By tying TW properties into AOL's internet service, they've achieved the holy grail of ISP's: product differentiation.
Basically, dial-up internet access is a commodity, and has been since the mid/late '90's. There are some variations in customer service, e-mail/web space, and other little things, but ISP's are essentially offering the same product (access to the public internet) for the same price (~$20/month). For most customers, choosing a dial-up ISP might as well be done by flipping a coin. This is not the ideal situation for businesses, since they really don't have any basis for competition beyond flashy commercials and price cuts (not much of a margin for those). If you can't differentiate yourself from your competition, it's hard to increase your market share.
AOL now has the opportunity to truly separate themselves from their competition. History buffs might recognize that this is what AOL (and Prodigy, Compuserve, etc.) had in their early days. There wasn't much on the internet, and so they were able to sell unique content: chatrooms, magazine articles, software downloads, etc. Of course, all of that stuff eventually sought out a wider audience, and much of what made AOL unique diffused across public space, accessible to customers of any number of ISP's. AOL was now in the unenviable position of competing against (comparatively) bare-bones ISP, who could offer unmetered access at lower monthly rates. Despite the fact that AOL has consistently cost a few dollars more per month, they maintained a large customer base (inertia and advertising being the biggest reasons, probably).
Now, AOL has something to sell. Lots and lots of magazines. TV shows and movies. Access to a media empire (Wasn't that why they merged in the first place?). When consumers are deciding on an ISP, this will influence their decision. For a few extra dollars a month (I think it's $23.95/month compared to $19.95/month for other national ISP's, but correct me if I'm wrong), subscribing to AOL gives you access to the whole internet PLUS exclusive TW content. I suspect a lot of people will look at this as if they were getting dozens of magazine subscriptions for $4 per month, if it's marketed properly.
Of course, it might not work like this. Frankly, I think most people who want to be online are already online. The same inertia effect that's kept AOL's subscriber base intact might keep people from switching to AOL, even if they think they'll get a better deal there. There may not be many new customers to be found. Another danger is that if this isn't marketed properly, potential subscribers won't realize what they could be getting; the extent of TW's media holdings can't be overemphasized in any ad campaign. The only effect would then be to piss off non-AOL subscribers who currently read TW content online, but won't be able to in the future.
Bottom line: if done properly, this could get AOL/TW a lot of new subscribers. Do it poorly, and they'll just alienate a great number of people.
Re:Per Transaction Fees Suck...
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· Score: 3, Informative
You've got it backwards. Debit cards (when used as debit cards and not as credit cards) charge much lower fees. There was a report on NPR's All Things Considered a few days ago, which gave numbers. On a $100 purchase, the credit card fee was a few dollars (~= 3%), while for the debit card fee was ~$0.09. The problem is that most debit cards are "branded" with Visa or MasterCard logos, and can be used as credit cards. Using a debit card as a credit card incurs credit card fees, despite the fact that the money still comes out of your checking account. When using a debit card, it's important to have it swiped as a debit card. That is, if you care about the merchant's fees.
There are so many grossly misinformed posts on this article, that it's hard to choose which one to respond to. I'll take a crack at this one.
"gravito-xxxxxx" forces are a quite common (among astrophysicists) way of referring to some very real consequences of the Einstein equation. The Einstein equation is the complicated, non-linear equation which describes how mass/energy and pressures couple to the curvature of spacetime. At its face, it is hardly similar to the Maxwell equations which describe electric and magnetic fields.
One way to make the Einstein equation tractable is to linearize it. I.e. start with a flat (Euclidean) spacetime, and only consider 1st-order perturbations on that. This results in a linear theory which is quite capable of describing gravitational waves, Mercury's precession, and many other "common" consequences of General Relativity (not black holes, worm holes, or any other region of strong gravity).
These linearized equations, like the Maxwell equations, do leave gauge freedom. For a particular choice of gauge, you can cast the linearized Einstein equations in a form which bears a striking resemblance to the Maxwell equations. There are some key differences, perhaps the most critical of which is the lack of a displacement current in the gravitational Ampere's Law. This is what prevents screening of the gravitoelectric field (at least to linear order).
In any event, this similarity between the Maxwell equations and the linearized Einstein equations is what gives rise to the gravitoelectric and gravitomagnetic fields (analogues to the electric and magnetic fields, of course). So don't think "bunk" when you encounter these terms. They're quite real, and are commonly found in the General Relativity literature.
Growing up when the USSR was still around, I never thought I'd see the day when Americans were turning to Pravda for accurate reporting. Somewhere, Nikita Khrushchev is laughing his ass off.:)
As evidenced by the popularity of "Braveheart" and "Highlander", among others, I would think that any sport involving irate people with swords would be VERY TV friendly.:)
Myrinet (on a per-node basis) is actually a more significant cost than the CPU's, for many clustering projects. It runs around $2,000 per machine. Furthermore, the balance between fast processors/many processors depends strongly on the problem at hand.
When you attempt to distribute a problem (a non-trivial problem, one that isn't embarassingly parallel), you have to strike a balance between the load on a single processor (or single SMP machine), and the overhead associated with message passing. Many research groups who build their own clusters go through extensive analysis of their particular problems to find the appropriate "sweet spot". For this machine, which will no doubt be used for many dissimilar projects, I don't know how they determined how much per-node power they needed. With a $53million grant, I bet they just went with the simple solution: as much as they can get:).
My point is just that the assumption that the CPU is the biggest expense is erroneous when dealing with specialized networking equipment like Myrinet, and that trading processor power for numbers isn't always a good bet.
"Yeah, average for Olympians, and that's makes up about 5% of society."
5% of people are Olympians? Damn. In the US, for example, there are about 300 million people. 5% of that is 15 million. If everyone lives to be 80, there will be 20 Olympics during the average lifetime. If everyone goes to the games just one, that means that the US is sending 750,000 representatives to the Olympics every four years.
Even NBC would find it hard to do that many human-interest stories.:)
When you purchase a car from a dealer, they remove the cardboard advertisements, and replace them with temporary, cardboard license plates. They look like regular plates, in that they have numbers and such, but the expire after a limited amount of time (varies by state, usually about 90 days). It takes a while after you register your car for the real, metal plates to arrive from the Department of Motor Vehicles (substitute your state's name for that office), and you need something on the car while you drive around before that.
However, these plates don't just sit on the car while it's on the dealer's lot. You only get them when you buy the car. That's why you find it suspicious.
Whoa...you're WAY off. The "old theory" of superconductivity (the BCS theory, developed by Bardeen, Cooper, and Schreiffer) is still very much correct. NOTHING about this discovery implies that the theory is wrong, incomplete, or anything of the sort. What's remarkable is that noone expected to find a "conventional" (I'll explain below what I mean by "conventional") superconducting metal with a transition temperature much above the ~20K temperatures which have already been achieved in niobium alloys.
So anyway, on to what I mean by "conventional" superconductor. Electrons in metals interact with the underlying crystalline lattice; momentum is exchanged by causing the lattice to vibrate. Normally, two electrons will repel each other, since they both have negative electric charges. However, in a crystal, the lattice can mediate an effective ATTRACTIVE interaction between electrons (an electron-phonon-electron interaction, for those who like terminology). Thus the electrons can form bound pairs, which behave quite differently than lone electrons (they behave like "bosons"), and the system can enter the superconducting state (which is rather similar to the superfluid state in, e.g., liquid helium-4). Just what that state is would require a much longer explanation.
As a consequence of the fact that the electron pairing is due to the lattice, the transition temeperature (and other properties) of a conventional superconductor is influenced by the mass of the nuclei in the lattice. This phenomenon is known as the "isotope effect", and was a key piece of evidence which lead to the development of the BCS theory. I felt I had to correct the parent post precisely because of this fact. This recently discovered superconductor shows a variation of transition temperature with boron isotope mass which is just about exactly what the theory of the isotope effect predicts. This is STRONG evidence that this new MgB2 superconductor is a conventional superconductor, albeit one with an unexpectedly high transition temperature.
The "high-Tc" (ceramic, YBCO, etc.) superconductors seem to have a different pairing mechanism (i.e. not electron-phonon-electron, as in BCS), and thus require a different theoretical explanation. That doesn't mean BCS is wrong, just that the ~15 year-old ceramics are in a different class of materials.
According to the complaint Nintendo filed (which has been linked to in other comments), it's not just the use of screenshots and the word "Pokemon" that they're objecting to. Given that the right to quote a published work (e.g. for a review) is solidly protected as fair use, I think it's not a great leap to protect the use of screenshots (visual "quotes") to review and/or comment on a videogame, as in a strategy guide. However, Nintendo is also objecting to the reproduction of Pokemon artwork and trading cards in the strategy guide.
While I feel that the right to use screenshots would have likely been upheld over Nintendo's objections, it seems that the use of copyrighted artwork goes beyond fair use. It is clearly possible to publish an unofficial strategy guide, discussing the game in depth, without including trading card images. I could quote Harry Potter in a review of the books, but I don't think I should be allowed to cut and paste pictures of the characters. The copyrighted material used in the unofficial strategy guide goes beyond what is necessary to discuss the game, and so has no right to be protected.
You're right, I think. Most of the new high-Tc superconductors are type-2. Even conventional type-2 superconductors tend to have higher critical temperatures (and critical fields, and critical currents) than type-1's.
By the way, PHYS 317 was a great course (I was a physics major myself). Is LePage still teaching it?
You don't need a band gap above the critical temperature. Although many really good metals aren't superconductors (e.g. Au and Ag), many other metals (which have no band gap, of course) are, like Nb. The normal-superconducting transition opens up a gap between the paired states at the Fermi surface and the next-lowest ("broken pair") states, but it's not necessary for there to be a gap in the normal state. That would imply that ONLY insulators and semiconductors could be superconductors.
Sorry, couldn't help myself. One minor correction. The type of superconductors which were discovered in the 1980's (1984, by Bednorz and Muller at IBM-Zurich, I think) are known as "high-temperature" superconductors. They appear to be fundamentally different than previous superconductors (conventional, or low-temperature). High-temperature superconductors superconduct at roughly liquid nitrogen temperatures (77K).
Most low-temperature superconductors are pure metals, alloys, or oxides (like Nb, NbTi, or NbO2). Most high-temperature superconductors are, as Maurice said, cuprates. For example, YBCO (Yttrium Barium Copper Oxide). It appears that the actual "supercurrents" flow in the 2-dimensional copper-oxide sheets.
Now for the actual correction (to eliminate a bit of confusion). There are type-1 and type-2 superconductors, although those terms refer exclusively to classes of LOW-temperature superconductors. The difference lies in how their conductivity is affected by a magnetic field. Basically, type-1 superconductors have a sharp transition between superconductivity at low magnetic fields, and normal conductivity above a critical field (at constant temperature). Type-2's have a much more gradual transition. Of course, that's only a functional definition, and it isn't the whole story.
Basically, HIGH-temperature superconductors were what was discovered in the 1980's, and type-1 and type-2 refer to types of conventional superconductors.
Atomic force microscopes measure the Van der Waals forces between atoms in the probe and on the surface. Van der Waals forces arise between neutral atoms, and are essentially electrostatic dipole interactions. A neutral (non-polar) molecule or atom will acquire a dipole moment due to the fluctuations in its "electron cloud", this dipole can induce a dipole moment in a nearby neutral atom, and thus you get a dipole-dipole interaction, which is considerably weaker than the dipole forces between polar molecules (which have permanent dipole moments).
In principal, it works the same way as a scanning tunneling electron microscope. You have a force which depends strongly on distance (exponentially for the tunneling current in an STM, roughly 1/(distance^6) for the Van der Waals forces in an AFM), and that allows you to measure distances precisely by measuring the variation in forces (or currents).
So to sum up, AFM's operate on electrostatic (sort of) forces between atoms on the surface and in the tip.
Actually, it's not trivial. AFM's are quite prone to vibrations, etc. (I'm not so sure about outside electromagnetic interference). A laboratory AFM setup will use a lot of damping equipment (stabilized tables, vibration damping foam, etc.) to protect it from minute jars. The precision required to bring a tip to within angstroms of a surface is almost unbelievable. I'm sure the researchers have figured out a way to overcome the difficulties, but I bet it's not a trivial extension of current hard disk technology.
Don't knock the first poster's comment. It's a realistic caveat. The inventors of the scanning tunneling electron microscope won a Nobel Prize for their work, and that was essentially all in the details (i.e. the physical principle behind it is pretty simple). Not that I'm comparing this advance to that, but still, nothing's as easy as it seems.
I don't know, that ad might be pretty effective as it is. Does anyone else think that George W. himself is the best possible reason for voting for Gore?:)
Pretty much everything in a history BOOK is a fact. It doesn't mean that those books can't be copyrighted. A lecture is a specific way of presenting facts, interspersed with interpretations of those facts. In that sense, it most certainly is copyrightable material. If the professor wrote up their notes and distributed them, they would have every right to copyright protection.
Most lecture note companies distribute lecture notes for specific courses, taught by specific professors. While Freud's theories are the same everywhere, how they're presented and what students are expected to learn from them varies a lot. The issue at hand is whether lecture notes as transcribed by STUDENTS are still protected under the professor's copyright of HIS lecture notes. That's a bit more questionable, in my opinion.
I had no idea this act existed. And I'm certainly not happy with it. The LACK of legal protection for "trade secrets" has, I dare say, encouraged innovation for as long as patents have existed (incidentally, about as long as the US has existed).
Information which is patented is effectively entered into the public domain. Sure, the inventor has an exclusive right to use it for a while, but in exchange for that right, he/she must provide complete documentation of their invention to the patent office. Those specs are then available for anyone to look at. Sure, you can't just get the shop drawings for widget X from the PTO and go out and manufacture them (at least not for, what is it, 17 years?). But you can look at how widget X is made, and that might provide you with the inspiration to develop the new, improved widget Y. This is, and always has been, the point of patent law. Guarantee the inventor an exclusive right to use their invention for a while, and in exchange they'll share their secrets with the public. Freedom and innovation for all!
Now trade secrets are a different story. Sometimes companies WON'T patent stuff because they don't want to make their secret information public, knowing they'll lose their rights to it in time. The classic example is the formula for Coke (this isn't an urban legend, is it?). It's not patented, it's just kept secret. That way, so long as Coke is careful, their proprietary beverage is theirs alone, forever.
Of course, keeping something as an unpatented "trade secret" has is drawbacks. If you discover, or somehow obtain, the formula for Coke tomorrow, you are free to sell it, make an identical Coke knock-off, etc. They've abandoned the legal protection a patent would have given them in the hopes that they could keep it a secret, and thus have exclusive rights, forever. It's a gamble that they decided to take.
But oh, what about this new trade secret law? Is it now illegal to copy a company's "trade secret"? If so, then what's a patent good for? (And why have I asked three questions in a row?) Nothing. If you can maintain an exclusive right to your product/invention indefinitely through trade secret protection, then why settle for the limited-time defense of a patent? I can't imagine too many companies opting to patent what they can just claim as a trade secret. And that, in the end, will defeat the purpose of the patent. No more public records of inventions. Innovation will certainly be hurt.
Agreed. Releasing features incrementally is the way to go. It's what open source projects REALLY excel at. The Mozilla team codes a browser (and maybe a mail client). The ship it, it works, people improve the code, etc. THEN someone decides that they really want to use MathML (or whatever). So they write a module, or perhaps it makes it into the mainline code for version 2.0. Then version 3 adds more stuff, 4 still more,..., until version 20 is reached and Mozilla does everything from text editing to version control:). The point is: give people a 1.0 BROWSER, and they will decide if it should become enormous and all-encompassing (Mozilla Communicator?). "Release early, release often" is a mantra for bug-fixing, not for the introduction of partially-implemented features.
Can you imagine if EMACS had worked like Mozilla? A list of milestones dating back to the early '80's, actually documenting the impending introduction of every possible feature? Nope, it just grew as it matured. But the most important thing was that it was a stable, effective text editor before it became a newsreader and e-mail client.
Actually, although Joannopoulos does do a lot of electronic structure stuff (and is quite good at it), the research which lead to this mirror breakthrough comes from the other half of his group. He also does research on "photonics", which is essentially the study of light propagation through materials with varying dielectric constant. The scale is well beyond that of ab-initio electronic structure; visible light wavelengths are an order of magnitude larger than lattice constants/interatomic spacings, which are of course the relevant length scales for (valence) electrons. Photonics is done more-or-less macroscopically; everything is derived from good old Maxwell's equations.
That being said, what Joannopoulos' photonics group does is essentially very similar to band structure calculations. Assuming there's a periodicity in the dielectric constant in the material (just like a periodic potential in a crystal!), then Maxwell's equations can be recast in a form which bears a striking resemblance to the Schrodinger equation for an electron in a solid. What they get out of that is a "band structure" for light. Certain frequencies are allowed, some are forbidden. Thus it becomes possible to make a perfectly selective waveguide. Just design a material which has "band gaps" at the frequencies you want to filter, shine the light through, and let nature (Bragg reflections?:) ) take its course. Of course, you can also do other cool stuff, like introducing defects, which create localized states just like in solids. This is a source of little "light boxes". There are a lot more similarities; Joannopoulos et al. have written a really good book on the subject called "Photonic Crystals". It's short and quite easy to read, but a few years out of date . Also, if you know how to make the analogies, it makes an excellent introduction to concepts of electronic band theory.
The above explanation might be incorrect in its details. I read the book pretty quickly and superficially on the subway when I was visiting MIT this spring (opposite of you: I was a physics undergrad at Cornell, and will be going to MIT this fall). I encourage you (or anyone) to look into photonics more closely. It's really fascinating.
Actually, it's not illegal at all to give products away with the sole intent of cutting off a company's "oxygen supply" (was it Gates who gave us that wonderful expression?). I'm perfectly justified in giving away copies of bestselling books in an attempt to drive Barnes and Noble and Amazon out of business. I'd just lose a lot of money, though, and drive myself out of business.
It's a different story, however, if I had a monopoly. Let's say I'm now MegaBooks(tm), and this little Barnes and Noble store tries to open up shop. Now I could give away books to drive them out of business, and I'd probably succeed. They'd run out of money long before I did, and I'd end up with the market all to myself once again. THAT would be illegal.
I believe it's also illegal to, e.g., use a monopoly position in another market to leverage one's way into another market. For example, if I, say, had a monopoly in the desktop operating systems market, I couldn't start an online bookstore which gave away books to try and steal the market from Amazon and BN. The law is designed to prevent me from using the relatively bottomless profits a monopoly position provides to gain an advantage over competitors who have to actually make money on their business.
Throughout the whole Microsoft thing, that was the issue that most people didn't seem to understand. Monopolies just aren't allowed to behave like other businesses. Many people argued that Microsoft was just behaving as every other software company does, but what's okay for Novell just isn't okay for Microsoft. Sun can give away StarOffice, because it doesn't have a monopoly to leverage. To summarize: it's okay to be a monopoly, you just have to behave differently (under penalty of law, of course). If you're not a monopoly, then pretty much everything short of firebombing warehouses is just fine (okay, price-fixing is still bad, and anti-competitive agreements, and...).
It seems to me that the primary issue with Deja's actions is whether or not adding markup to a document changes it. If you look at the sample message, what Deja has done is hyperlink a word in the message, and prefix it with an orange triangle. The WORDS in the message are exactly what the poster had originally written. There's no copyright issue with Deja taking messages off USENET, the issue seems to be whether or not Deja is improperly modifying messages and attributing them to the author.
I'm inclined to think that they're not. If you write: I don't like them commies.
And I want to quote you for my story on McCarthyism, I am perfectly justified in writing: "I don't like them [sic] commies."
I've changed your quote to indicate that the grammatical error was yours, and not a mistake in the quotation. I've done so by using a recognized editorial comment, which is distinguishable from your text by the brackets. Deja's hyperlinks are identified by the little triangle, and as such are distinguishable from the author's original text.
Deja already converts USENET posts to HTML, already changes markup to make links clickable, etc., and is in no way changing the author's message. Their added links are clearly marked as NOT being from the original author, and as such they are simply adding a different "formatting", if you will, to the message.
What exactly were the axes for? Destroying the computers, or fighting off those who are coming to steal your data? Old methods work well, but REALLY old methods work best of all:).
The FSF boycott is an excellent point. I'd completely forgotten about it. I remember looking for free programming tools for the mac several years ago (before MPW became free). I figured that there would be something along the lines of DJGPP for DOS, but there were essentially no free C/C++ compilers available. Very disappointing, as it kept me from exploring mac programming. I, of course, probably wouldn't have produced anything useful, but it would have been open source:).
So it seems to me that the lack of good, free compilers did a great deal to slow free software development on macs. And, as cwis pointed out, the FSF boycott certainly curtailed a port of GCC, which might have made a big difference. It may just be that history, and not philosophy, has held back open source development on the mac.
Slashdot Mirror
Despite what other posters seem to think, this switch, if properly promoted, could get AOL more subscribers. By tying TW properties into AOL's internet service, they've achieved the holy grail of ISP's: product differentiation.
Basically, dial-up internet access is a commodity, and has been since the mid/late '90's. There are some variations in customer service, e-mail/web space, and other little things, but ISP's are essentially offering the same product (access to the public internet) for the same price (~$20/month). For most customers, choosing a dial-up ISP might as well be done by flipping a coin. This is not the ideal situation for businesses, since they really don't have any basis for competition beyond flashy commercials and price cuts (not much of a margin for those). If you can't differentiate yourself from your competition, it's hard to increase your market share.
AOL now has the opportunity to truly separate themselves from their competition. History buffs might recognize that this is what AOL (and Prodigy, Compuserve, etc.) had in their early days. There wasn't much on the internet, and so they were able to sell unique content: chatrooms, magazine articles, software downloads, etc. Of course, all of that stuff eventually sought out a wider audience, and much of what made AOL unique diffused across public space, accessible to customers of any number of ISP's. AOL was now in the unenviable position of competing against (comparatively) bare-bones ISP, who could offer unmetered access at lower monthly rates. Despite the fact that AOL has consistently cost a few dollars more per month, they maintained a large customer base (inertia and advertising being the biggest reasons, probably).
Now, AOL has something to sell. Lots and lots of magazines. TV shows and movies. Access to a media empire (Wasn't that why they merged in the first place?). When consumers are deciding on an ISP, this will influence their decision. For a few extra dollars a month (I think it's $23.95/month compared to $19.95/month for other national ISP's, but correct me if I'm wrong), subscribing to AOL gives you access to the whole internet PLUS exclusive TW content. I suspect a lot of people will look at this as if they were getting dozens of magazine subscriptions for $4 per month, if it's marketed properly.
Of course, it might not work like this. Frankly, I think most people who want to be online are already online. The same inertia effect that's kept AOL's subscriber base intact might keep people from switching to AOL, even if they think they'll get a better deal there. There may not be many new customers to be found. Another danger is that if this isn't marketed properly, potential subscribers won't realize what they could be getting; the extent of TW's media holdings can't be overemphasized in any ad campaign. The only effect would then be to piss off non-AOL subscribers who currently read TW content online, but won't be able to in the future.
Bottom line: if done properly, this could get AOL/TW a lot of new subscribers. Do it poorly, and they'll just alienate a great number of people.
You've got it backwards. Debit cards (when used as debit cards and not as credit cards) charge much lower fees. There was a report on NPR's All Things Considered a few days ago, which gave numbers. On a $100 purchase, the credit card fee was a few dollars (~= 3%), while for the debit card fee was ~$0.09. The problem is that most debit cards are "branded" with Visa or MasterCard logos, and can be used as credit cards. Using a debit card as a credit card incurs credit card fees, despite the fact that the money still comes out of your checking account. When using a debit card, it's important to have it swiped as a debit card. That is, if you care about the merchant's fees.
There are so many grossly misinformed posts on this article, that it's hard to choose which one to respond to. I'll take a crack at this one.
"gravito-xxxxxx" forces are a quite common (among astrophysicists) way of referring to some very real consequences of the Einstein equation. The Einstein equation is the complicated, non-linear equation which describes how mass/energy and pressures couple to the curvature of spacetime. At its face, it is hardly similar to the Maxwell equations which describe electric and magnetic fields.
One way to make the Einstein equation tractable is to linearize it. I.e. start with a flat (Euclidean) spacetime, and only consider 1st-order perturbations on that. This results in a linear theory which is quite capable of describing gravitational waves, Mercury's precession, and many other "common" consequences of General Relativity (not black holes, worm holes, or any other region of strong gravity).
These linearized equations, like the Maxwell equations, do leave gauge freedom. For a particular choice of gauge, you can cast the linearized Einstein equations in a form which bears a striking resemblance to the Maxwell equations. There are some key differences, perhaps the most critical of which is the lack of a displacement current in the gravitational Ampere's Law. This is what prevents screening of the gravitoelectric field (at least to linear order).
In any event, this similarity between the Maxwell equations and the linearized Einstein equations is what gives rise to the gravitoelectric and gravitomagnetic fields (analogues to the electric and magnetic fields, of course). So don't think "bunk" when you encounter these terms. They're quite real, and are commonly found in the General Relativity literature.
Growing up when the USSR was still around, I never thought I'd see the day when Americans were turning to Pravda for accurate reporting. Somewhere, Nikita Khrushchev is laughing his ass off. :)
As evidenced by the popularity of "Braveheart" and "Highlander", among others, I would think that any sport involving irate people with swords would be VERY TV friendly. :)
Myrinet (on a per-node basis) is actually a more significant cost than the CPU's, for many clustering projects. It runs around $2,000 per machine. Furthermore, the balance between fast processors/many processors depends strongly on the problem at hand.
:).
When you attempt to distribute a problem (a non-trivial problem, one that isn't embarassingly parallel), you have to strike a balance between the load on a single processor (or single SMP machine), and the overhead associated with message passing. Many research groups who build their own clusters go through extensive analysis of their particular problems to find the appropriate "sweet spot". For this machine, which will no doubt be used for many dissimilar projects, I don't know how they determined how much per-node power they needed. With a $53million grant, I bet they just went with the simple solution: as much as they can get
My point is just that the assumption that the CPU is the biggest expense is erroneous when dealing with specialized networking equipment like Myrinet, and that trading processor power for numbers isn't always a good bet.
"Yeah, average for Olympians, and that's makes up about 5% of society."
:)
5% of people are Olympians? Damn. In the US, for example, there are about 300 million people. 5% of that is 15 million. If everyone lives to be 80, there will be 20 Olympics during the average lifetime. If everyone goes to the games just one, that means that the US is sending 750,000 representatives to the Olympics every four years.
Even NBC would find it hard to do that many human-interest stories.
When you purchase a car from a dealer, they remove the cardboard advertisements, and replace them with temporary, cardboard license plates. They look like regular plates, in that they have numbers and such, but the expire after a limited amount of time (varies by state, usually about 90 days). It takes a while after you register your car for the real, metal plates to arrive from the Department of Motor Vehicles (substitute your state's name for that office), and you need something on the car while you drive around before that.
However, these plates don't just sit on the car while it's on the dealer's lot. You only get them when you buy the car. That's why you find it suspicious.
Whoa...you're WAY off. The "old theory" of superconductivity (the BCS theory, developed by Bardeen, Cooper, and Schreiffer) is still very much correct. NOTHING about this discovery implies that the theory is wrong, incomplete, or anything of the sort. What's remarkable is that noone expected to find a "conventional" (I'll explain below what I mean by "conventional") superconducting metal with a transition temperature much above the ~20K temperatures which have already been achieved in niobium alloys.
So anyway, on to what I mean by "conventional" superconductor. Electrons in metals interact with the underlying crystalline lattice; momentum is exchanged by causing the lattice to vibrate. Normally, two electrons will repel each other, since they both have negative electric charges. However, in a crystal, the lattice can mediate an effective ATTRACTIVE interaction between electrons (an electron-phonon-electron interaction, for those who like terminology). Thus the electrons can form bound pairs, which behave quite differently than lone electrons (they behave like "bosons"), and the system can enter the superconducting state (which is rather similar to the superfluid state in, e.g., liquid helium-4). Just what that state is would require a much longer explanation.
As a consequence of the fact that the electron pairing is due to the lattice, the transition temeperature (and other properties) of a conventional superconductor is influenced by the mass of the nuclei in the lattice. This phenomenon is known as the "isotope effect", and was a key piece of evidence which lead to the development of the BCS theory. I felt I had to correct the parent post precisely because of this fact. This recently discovered superconductor shows a variation of transition temperature with boron isotope mass which is just about exactly what the theory of the isotope effect predicts. This is STRONG evidence that this new MgB2 superconductor is a conventional superconductor, albeit one with an unexpectedly high transition temperature.
The "high-Tc" (ceramic, YBCO, etc.) superconductors seem to have a different pairing mechanism (i.e. not electron-phonon-electron, as in BCS), and thus require a different theoretical explanation. That doesn't mean BCS is wrong, just that the ~15 year-old ceramics are in a different class of materials.
According to the complaint Nintendo filed (which has been linked to in other comments), it's not just the use of screenshots and the word "Pokemon" that they're objecting to. Given that the right to quote a published work (e.g. for a review) is solidly protected as fair use, I think it's not a great leap to protect the use of screenshots (visual "quotes") to review and/or comment on a videogame, as in a strategy guide. However, Nintendo is also objecting to the reproduction of Pokemon artwork and trading cards in the strategy guide.
While I feel that the right to use screenshots would have likely been upheld over Nintendo's objections, it seems that the use of copyrighted artwork goes beyond fair use. It is clearly possible to publish an unofficial strategy guide, discussing the game in depth, without including trading card images. I could quote Harry Potter in a review of the books, but I don't think I should be allowed to cut and paste pictures of the characters. The copyrighted material used in the unofficial strategy guide goes beyond what is necessary to discuss the game, and so has no right to be protected.
You're right, I think. Most of the new high-Tc superconductors are type-2. Even conventional type-2 superconductors tend to have higher critical temperatures (and critical fields, and critical currents) than type-1's.
By the way, PHYS 317 was a great course (I was a physics major myself). Is LePage still teaching it?
You don't need a band gap above the critical temperature. Although many really good metals aren't superconductors (e.g. Au and Ag), many other metals (which have no band gap, of course) are, like Nb. The normal-superconducting transition opens up a gap between the paired states at the Fermi surface and the next-lowest ("broken pair") states, but it's not necessary for there to be a gap in the normal state. That would imply that ONLY insulators and semiconductors could be superconductors.
Sorry, couldn't help myself. One minor correction. The type of superconductors which were discovered in the 1980's (1984, by Bednorz and Muller at IBM-Zurich, I think) are known as "high-temperature" superconductors. They appear to be fundamentally different than previous superconductors (conventional, or low-temperature). High-temperature superconductors superconduct at roughly liquid nitrogen temperatures (77K).
Most low-temperature superconductors are pure metals, alloys, or oxides (like Nb, NbTi, or NbO2). Most high-temperature superconductors are, as Maurice said, cuprates. For example, YBCO (Yttrium Barium Copper Oxide). It appears that the actual "supercurrents" flow in the 2-dimensional copper-oxide sheets.
Now for the actual correction (to eliminate a bit of confusion). There are type-1 and type-2 superconductors, although those terms refer exclusively to classes of LOW-temperature superconductors. The difference lies in how their conductivity is affected by a magnetic field. Basically, type-1 superconductors have a sharp transition between superconductivity at low magnetic fields, and normal conductivity above a critical field (at constant temperature). Type-2's have a much more gradual transition. Of course, that's only a functional definition, and it isn't the whole story.
Basically, HIGH-temperature superconductors were what was discovered in the 1980's, and type-1 and type-2 refer to types of conventional superconductors.
Atomic force microscopes measure the Van der Waals forces between atoms in the probe and on the surface. Van der Waals forces arise between neutral atoms, and are essentially electrostatic dipole interactions. A neutral (non-polar) molecule or atom will acquire a dipole moment due to the fluctuations in its "electron cloud", this dipole can induce a dipole moment in a nearby neutral atom, and thus you get a dipole-dipole interaction, which is considerably weaker than the dipole forces between polar molecules (which have permanent dipole moments).
In principal, it works the same way as a scanning tunneling electron microscope. You have a force which depends strongly on distance (exponentially for the tunneling current in an STM, roughly 1/(distance^6) for the Van der Waals forces in an AFM), and that allows you to measure distances precisely by measuring the variation in forces (or currents).
So to sum up, AFM's operate on electrostatic (sort of) forces between atoms on the surface and in the tip.
Actually, it's not trivial. AFM's are quite prone to vibrations, etc. (I'm not so sure about outside electromagnetic interference). A laboratory AFM setup will use a lot of damping equipment (stabilized tables, vibration damping foam, etc.) to protect it from minute jars. The precision required to bring a tip to within angstroms of a surface is almost unbelievable. I'm sure the researchers have figured out a way to overcome the difficulties, but I bet it's not a trivial extension of current hard disk technology.
Don't knock the first poster's comment. It's a realistic caveat. The inventors of the scanning tunneling electron microscope won a Nobel Prize for their work, and that was essentially all in the details (i.e. the physical principle behind it is pretty simple). Not that I'm comparing this advance to that, but still, nothing's as easy as it seems.
I don't know, that ad might be pretty effective as it is. Does anyone else think that George W. himself is the best possible reason for voting for Gore? :)
Pretty much everything in a history BOOK is a fact. It doesn't mean that those books can't be copyrighted. A lecture is a specific way of presenting facts, interspersed with interpretations of those facts. In that sense, it most certainly is copyrightable material. If the professor wrote up their notes and distributed them, they would have every right to copyright protection.
Most lecture note companies distribute lecture notes for specific courses, taught by specific professors. While Freud's theories are the same everywhere, how they're presented and what students are expected to learn from them varies a lot. The issue at hand is whether lecture notes as transcribed by STUDENTS are still protected under the professor's copyright of HIS lecture notes. That's a bit more questionable, in my opinion.
I had no idea this act existed. And I'm certainly not happy with it. The LACK of legal protection for "trade secrets" has, I dare say, encouraged innovation for as long as patents have existed (incidentally, about as long as the US has existed).
Information which is patented is effectively entered into the public domain. Sure, the inventor has an exclusive right to use it for a while, but in exchange for that right, he/she must provide complete documentation of their invention to the patent office. Those specs are then available for anyone to look at. Sure, you can't just get the shop drawings for widget X from the PTO and go out and manufacture them (at least not for, what is it, 17 years?). But you can look at how widget X is made, and that might provide you with the inspiration to develop the new, improved widget Y. This is, and always has been, the point of patent law. Guarantee the inventor an exclusive right to use their invention for a while, and in exchange they'll share their secrets with the public. Freedom and innovation for all!
Now trade secrets are a different story. Sometimes companies WON'T patent stuff because they don't want to make their secret information public, knowing they'll lose their rights to it in time. The classic example is the formula for Coke (this isn't an urban legend, is it?). It's not patented, it's just kept secret. That way, so long as Coke is careful, their proprietary beverage is theirs alone, forever.
Of course, keeping something as an unpatented "trade secret" has is drawbacks. If you discover, or somehow obtain, the formula for Coke tomorrow, you are free to sell it, make an identical Coke knock-off, etc. They've abandoned the legal protection a patent would have given them in the hopes that they could keep it a secret, and thus have exclusive rights, forever. It's a gamble that they decided to take.
But oh, what about this new trade secret law? Is it now illegal to copy a company's "trade secret"? If so, then what's a patent good for? (And why have I asked three questions in a row?) Nothing. If you can maintain an exclusive right to your product/invention indefinitely through trade secret protection, then why settle for the limited-time defense of a patent? I can't imagine too many companies opting to patent what they can just claim as a trade secret. And that, in the end, will defeat the purpose of the patent. No more public records of inventions. Innovation will certainly be hurt.
I apologize, because I usually hate it when people post silly little comments in the middle of discussions, but:
"Johnny Welfare Garage Band" is a REALLY good name for a band.
Sorry again.
Agreed. Releasing features incrementally is the way to go. It's what open source projects REALLY excel at. The Mozilla team codes a browser (and maybe a mail client). The ship it, it works, people improve the code, etc. THEN someone decides that they really want to use MathML (or whatever). So they write a module, or perhaps it makes it into the mainline code for version 2.0. Then version 3 adds more stuff, 4 still more, ..., until version 20 is reached and Mozilla does everything from text editing to version control :). The point is: give people a 1.0 BROWSER, and they will decide if it should become enormous and all-encompassing (Mozilla Communicator?). "Release early, release often" is a mantra for bug-fixing, not for the introduction of partially-implemented features.
Can you imagine if EMACS had worked like Mozilla? A list of milestones dating back to the early '80's, actually documenting the impending introduction of every possible feature? Nope, it just grew as it matured. But the most important thing was that it was a stable, effective text editor before it became a newsreader and e-mail client.
Daniel,
:) ) take its course. Of course, you can also do other cool stuff, like introducing defects, which create localized states just like in solids. This is a source of little "light boxes". There are a lot more similarities; Joannopoulos et al. have written a really good book on the subject called "Photonic Crystals". It's short and quite easy to read, but a few years out of date . Also, if you know how to make the analogies, it makes an excellent introduction to concepts of electronic band theory.
Actually, although Joannopoulos does do a lot of electronic structure stuff (and is quite good at it), the research which lead to this mirror breakthrough comes from the other half of his group. He also does research on "photonics", which is essentially the study of light propagation through materials with varying dielectric constant. The scale is well beyond that of ab-initio electronic structure; visible light wavelengths are an order of magnitude larger than lattice constants/interatomic spacings, which are of course the relevant length scales for (valence) electrons. Photonics is done more-or-less macroscopically; everything is derived from good old Maxwell's equations.
That being said, what Joannopoulos' photonics group does is essentially very similar to band structure calculations. Assuming there's a periodicity in the dielectric constant in the material (just like a periodic potential in a crystal!), then Maxwell's equations can be recast in a form which bears a striking resemblance to the Schrodinger equation for an electron in a solid. What they get out of that is a "band structure" for light. Certain frequencies are allowed, some are forbidden. Thus it becomes possible to make a perfectly selective waveguide. Just design a material which has "band gaps" at the frequencies you want to filter, shine the light through, and let nature (Bragg reflections?
The above explanation might be incorrect in its details. I read the book pretty quickly and superficially on the subway when I was visiting MIT this spring (opposite of you: I was a physics undergrad at Cornell, and will be going to MIT this fall). I encourage you (or anyone) to look into photonics more closely. It's really fascinating.
Matt
Actually, it's not illegal at all to give products away with the sole intent of cutting off a company's "oxygen supply" (was it Gates who gave us that wonderful expression?). I'm perfectly justified in giving away copies of bestselling books in an attempt to drive Barnes and Noble and Amazon out of business. I'd just lose a lot of money, though, and drive myself out of business.
...).
It's a different story, however, if I had a monopoly. Let's say I'm now MegaBooks(tm), and this little Barnes and Noble store tries to open up shop. Now I could give away books to drive them out of business, and I'd probably succeed. They'd run out of money long before I did, and I'd end up with the market all to myself once again. THAT would be illegal.
I believe it's also illegal to, e.g., use a monopoly position in another market to leverage one's way into another market. For example, if I, say, had a monopoly in the desktop operating systems market, I couldn't start an online bookstore which gave away books to try and steal the market from Amazon and BN. The law is designed to prevent me from using the relatively bottomless profits a monopoly position provides to gain an advantage over competitors who have to actually make money on their business.
Throughout the whole Microsoft thing, that was the issue that most people didn't seem to understand. Monopolies just aren't allowed to behave like other businesses. Many people argued that Microsoft was just behaving as every other software company does, but what's okay for Novell just isn't okay for Microsoft. Sun can give away StarOffice, because it doesn't have a monopoly to leverage. To summarize: it's okay to be a monopoly, you just have to behave differently (under penalty of law, of course). If you're not a monopoly, then pretty much everything short of firebombing warehouses is just fine (okay, price-fixing is still bad, and anti-competitive agreements, and
It seems to me that the primary issue with Deja's actions is whether or not adding markup to a document changes it. If you look at the sample message, what Deja has done is hyperlink a word in the message, and prefix it with an orange triangle. The WORDS in the message are exactly what the poster had originally written. There's no copyright issue with Deja taking messages off USENET, the issue seems to be whether or not Deja is improperly modifying messages and attributing them to the author.
I'm inclined to think that they're not. If you write:
I don't like them commies.
And I want to quote you for my story on McCarthyism, I am perfectly justified in writing:
"I don't like them [sic] commies."
I've changed your quote to indicate that the grammatical error was yours, and not a mistake in the quotation. I've done so by using a recognized editorial comment, which is distinguishable from your text by the brackets. Deja's hyperlinks are identified by the little triangle, and as such are distinguishable from the author's original text.
Deja already converts USENET posts to HTML, already changes markup to make links clickable, etc., and is in no way changing the author's message. Their added links are clearly marked as NOT being from the original author, and as such they are simply adding a different "formatting", if you will, to the message.
What exactly were the axes for? Destroying the computers, or fighting off those who are coming to steal your data? Old methods work well, but REALLY old methods work best of all :).
The FSF boycott is an excellent point. I'd completely forgotten about it. I remember looking for free programming tools for the mac several years ago (before MPW became free). I figured that there would be something along the lines of DJGPP for DOS, but there were essentially no free C/C++ compilers available. Very disappointing, as it kept me from exploring mac programming. I, of course, probably wouldn't have produced anything useful, but it would have been open source :).
So it seems to me that the lack of good, free compilers did a great deal to slow free software development on macs. And, as cwis pointed out, the FSF boycott certainly curtailed a port of GCC, which might have made a big difference. It may just be that history, and not philosophy, has held back open source development on the mac.
Matt