Sorry that I'm unable to boil all of quantum mechanics and solid-state physics into a single easily-comprehensible slashdot posting, while spending a maximum of 15 minutes writing it. I included a few mentions to wikipedia (eg on modes) to aid you, and also quoted certain terms for you to look up on your own. Any quoted terms below, please look up yourself if you don't understand. This post can hopefully get you started. But I can't believe I'm being criticized for spending my own time trying to help someone entirely unfamiliar with the field understand something.
A mode is the collective motion of the atoms in the crystal, not a single frequency. A mode will oscillate at a specific frequency, however. If you write the 'equations of motion' for all atoms in the crystal in 'matrix' form, the modes would correspond to the 'eigenvalues' of that matrix. I'm sure these sentence will confuse you, but again, I can't boil linear algebra anad its application to mechanics down into a few understandable sentences to be comprehended in only a few minutes. f I tried to go too basic into all the details that post would evolveee into a textbook sized tome.
So a crystal will have several different modes. This is very much like quantum mechanics, where energy states are quantized, and each so-called 'eigenstate' has a specific 'wavefunction' associated with it. These oscillatory modes are called 'phonons', which are 'bosons'. The 'magnons' referred to in the articles are different modes. In those cases it's not vibrations they're 'quantizing' but magnetic interactions. The electrons on the atoms in the lattice are tiny 'magnetic dipoles', which can rotate, interact with magnetic fields, interact with other nearby electrons, etc. Again, if this paragraph confuses you then look up the terms in quotes.
Let me attempt a hopefully-understandable explanation. I'm a graduate student in experimental condensed-matter physics.
You can think about it in a coneptually-easier way by thinking about vibrations, which is more intuitive. The simplest model in which to think about vibrations would be in one dimension. Imagine you have a collection of some equal masses, equally spaced, with equal springs between each of those masses. If you excite the system anwhere (ie, push some of the masses), it will vibrate throughout the whole system because each 'atom' is coupled through the springs. The individual excitations of such a system would be the collective 'modes' of oscillation of the system. A mode is a specific oscillation that once set up will continue uninterrupted (without friction). For a simple one-dimensional system like the modes would be a sinusoidal oscillations of the system, where the wavelength of each mode would be the twice the length of the 'crystal' divided by an integer. See the wiki page on the Normal Mode with a cute animation.
You can extend this to three-dimensions by considering a three-dimensional grid of massive atoms, connected by springs. Real crystals don't have to be cubic, they can have a number of various arrangements (hexagonal, trigonal, diamond structure), and the effective spring constants can be different in different directions. But N masses, in 3 dimensions, will have 3N distinct modes. What's important to see is that each mode would have its own frequency, and wavelength, and typically the speed of propagation of each mode doesn't have to be the same. Also of note is that each mode has its own energy.
If you now consider a real crystal, and apply these same concepts but within the realm of quantum mechanics, you get a similar result, but each 'mode' now becomes a 'quanta' of lattice vibration. These vibration quanta are called phonons, which are bosons (they have spin 0, and bosons have integer spin). Even a small chunk of crystal will have on the order 10E23 atoms, so this is a huge number of allowed quantizations, and they can be thought of as a continuum. Each allowed 'mode' will again have its own frequency, wavelength, and energy. If you have a chunk of crystal at any non-zero temperature, any of the modes above the ground state (the ground state is the mode with the lowest allowed energy) can be 'occupied' with a finite probability. As you approach zero temperature, the probability of any mode above the ground state being occupied approaches zero.
A Bose-Einstein Condensate refers to an effective phase transition that happens as you cool the system and it becomes harder to excite the higher energy states as system becomes highly occupied in the ground state. There is a phase transition, the presence of which can be manifested by different qualities in things like specific heat, magnetization, magnetic susceptibility, etc. The crystal is still a solid crystal per-se (meaning it has a well-defined atomic ordering) but the occupations of the various modes of the system will drastically change, building into a near divergence at the ground state.
In the 'magnon' case as mentioned in TFA, you can think of it like phonons described above, but instead of two atoms exchanging vibrational energy, they are exchanging magnetic energy. Each electron is a spin-1/2 dipole (a fermion, not a boson), and there are interactions between two neighboring spins. Spin interactions are highly model dependent, meaning the types of atoms and shape of the crystal has huge impact on the interactions, which is why some materials are magnetic and some are non-magnetic. If you quantize the magnetic interactions you get spin-waves or magnons, similar to the sine-wave vibrational modes of the lattice above except the direction of the spin-moment changes instead of the atom displacement in the lattice.
I'm a doctoral student in physics (experimental condensed matter), and I can tell you that the US is already showing signs of declining in its lead in the sciences. While we are still very strong, many other regions (eg China and Europe) are also revealing trends of outpacing us.
At the 2006 March Meeting of the American Physical Society, some of us physicists (students and professors) went to Washington DC to lobby our Congressmen (see Congressional Visits ) about looming shortfalls of hard sciences in the USA and to encourage them to vote on upcoming bills to increase science funding.
There is alot of eye-opening data showing how Europe and Asia are significantly outpacing the US in terms of funding basic science education, in terms of the number of undergraduate and graduate degrees in the basic sciences, etc. Graphs plotting hard sciences degrees offered per year show the US lagging quite significantly (where we used to be leading 5+ years ago). Such trends are fairly worrisome because the hard sciences are tightly coupled to engineering and industry. Industries tend to attract to places with higher concentrations of scientists, so the US losing scientists will manifest itself in loss of industries down the line.
These are the kind of things that Senators and Representatives care about. To complicate matters there is a lag between industry and science, meaning that changes in science funding and numbers of scientists now won't be manifest significantly in industry until a decade or longer out. I met with two of my Congressmen and one of my Senators (really with their staffers), who luckily were familiar with this and assured us their bosses would be voting for the upcoming legislation to increase funding.
I come from a blue state, where the Congressmen are usually liberal with such education and funding programs. The red stater politicans were more hostile to funding sciences without seeing immediate industrial rewards. Such short-term thinking in those cases is what is leading to the decline of US scientific leadership.
On a different note, I've also seen major shifts in the attraction of foreign students to the US over the past few years. The Bush administration his been cracking down on student visas, which is also hurting our lead. In my department, within the past 3-4 years, each year a handful of good students accepted to the program are denied visas to enter the US (usually from China). Well, these guys aren't going to put their career on hold, and they'll go elsewhere. Many more foreign students are going to Canada and Europe, for instance, and the great brain drain that the US was known for the past few decades is beginning to show signs of reversing.
Anyway, I just wanted to throw in my two cents becuase I specifically lobbied my Congressmen about this very issue only six months ago.
Okay, good, we agree. I am in favor of paper ballots everywhere, IMHO it's much easier to hack an electronic voting machine (than stuff a ballot box. Especially since you're alone w/ the machine behind the curtain for a few minutes, while the ballot boxes are in full view always.
Anyway, it's quite shocking here to see so many people admiring Erlich when he's the typical sleezeball who's only taking advantage of a political opportunity to make himself look great and paint the opposition poorly.
You're being easily misled by the deliberately provocative slashdot blurb (or you're a republican plant).
There are two prominent Democrats on the elections committee, and obviously the committee fucked up due to the elections issues. The two 'Democrats' mentioned in the article are those two on this committee whose asses are now on the line for the fuckups so of course these two are trying to fight saying they've been doing a good job so far.
There hasn't been any general opposition by the Maryland Democratic Party, or even amongst a larger Democratic contingent. Erlich turned this into a partisan issue by pounding on the election irregularities by pointing to the incompetence of the election board, which has Democrats in the top spots. The race between Erlich and O'Malley for governor is quite ugly, these two have been bitter political rivals for the past few years already and there has been much ugliness previously (I've lived in Baltimore the past few years. O'Malley is the Democratic Baltimore mayor challenging Erlich, while Erlich is the Republican governor).
Erlich has been a political douchebag tool since he took office, he ignored election problems in Baltimore in 2004, for instance, and fully supported using the Diebold machines. And he mildly brushed aside criticism of the Ohio 2004 election irregularities. He's not some election hero, he's just your typical political opportunist, suddenly supporting an issue he previously ignored just becuase it's politically favorable for him to do so.
Remember, this guy is a candidate for governor, damn near everything he does in the spotlight has a political bent to it. He saw an opportunity and pounced on it.
The issue IS partisan, and if you have been following Maryland politics for awhile (I live in Baltimore) you'd know the vile relationship between Erlich and O'Malley (Erlich is the Republican governor up for re-election, O'Malley is the Democratic Baltimore mayor, challenging Erlich for governor). The problem is that the board in charge of the elections (and hence voting machines) has Democrats in the top positions.
It's pretty obvious that Erlich is taking advantage of the situation to turn it into a partisan issue by making the Democrats in charge of elections look bad, and to make himself look like a saint. The irony is that he previously poo-poo'd problems with Diebold machines in the Ohio 2004 presidential elections, while it was politically favorable for him to do so.
The intro slashdot blurb is also entirely misleading, because there's not a contingent of the Democratic Party against using paper ballots, in fact the article only mentions the two prominent Democratic members of the elections committee that are resisting, primarily because it's their own jobs that are being criticized by Erlich.
So make no mistake, this is ENTIRELY POLITICAL, Erlich is taking advantage of a political opportunity presented by the fuckups of two prominent Democrats, and trying to paint himself as pro-fair-elections and them as obstructionist in one sweep. Politically a smart thing to do, also somewhat misleading. Amazing to see how many slashdotters take politicians words at their face values.
You're sending an electromagnetic excitation (electric signal) down a waveguide (the wire amidst the circuit), plain and simple. Go take an E&M course if you really want to understand. Better yet, take a QED course (and all the prerequisites) if you REALLY want to understand.
Or, barring doing any hard work, at least take a look at these Wikipedia pages:
Over any arbitrary period of time, if there's a net DC applied during that time (eg, an oscillating signal at 1000 Hz will look relatively like DC on the timescale of microseconds), then the electrons will drift.
It's a complicated problem because they don't really 'drift' per se, but are really scattered around, with a preference to go along the electric field (actually, against it since they're negatively charged). The electrons themselves actual travel travel fairly quickly, but they're constantly scattering off each other, and also off of positive ion cores, lattice defects, and there are also magnetic interactions, spin interactions where electrons of similar spin may scatter differently than those of opposite spin, all kinds of other quantum effects, etc. But the bottom line, from a statistical ensemble approach, is that there will be a non-zero drift if there is a non-zero electric field.
But the signal is still transmitted by the electrons, not some EM pulse.
Yes and no, the signal is actually photonic in nature, it's an electromagnetic oscillation travelling down the wire, which itself is nothing more than a simple waveguide. So you're sending photons down the wire, photons being the 'particles' exchanged by two electrons that exhibit Coulomb repulsion.
As others have noted, the drift velocity of electrons is fairly slow, this is the average speed a single electron will migrate along a device in the presence of an electric field (ie, in an applied voltage across the device).
However, a changing voltage signal will propagate at speeds of order c (smaller than c, of course). The 'wires' ror traces unning on the microprocessor are basically transmission lines, so you're really transmitting electromagnetic signals. This is just like standard textbook transmission lines (eg, coaxial cable or waveguide). And of course in those cases, even at low frequencies of MHz waveforms, you're really sending photons, which are nothing but quanta of electromagnetic radiation, down the transmission line. Very long-wavelength photons, but still photons none-the-less.
The limit of the speed of light (or of signal propagation) is one reason CPU's need to be small, so various transistors can talk to each other within an appropriate number of clock cycles. Another very important reason is that every little trace, or wire, on the CPU itself is a transmission line, and as such has its own self-inductance. It also has mutual inductances between other lines, as well as capacitive coupling between ground planes and other devices. Thse parasitic capacitances and inductances act as low-pass filters, effectively reducing the bandwidth of the transmission lines. So chip designers, in the push for more GHz, are always trying to reduce these parasitic elements by making their devices smaller and smaller.
What this latest research probably implies isn't necessarily much in terms of a single electronic CPU going much faster, but with future advances in optical signal processing, it can allow optical elements to be grouped closer together and allow for faster optical processing. Additionally, it may increase the bandwidth for signals from CPU to optical transmission lines (eg, fiber optics) by grouping them more tightly to the processor.
It's a patent on automatically providing all of the different possible conjugation forms of any verb on the fly, which is something I, for one, haven't seen before and think could be pretty useful...
Yup, that described by your clarification has certainly never been done before .
I think it's really sad to see the fans to be so rabid at times.
actually, such silly behavior is no different from the linux and bsd zealotry that is just as prevalent on places like slashdot. But for whatever reason it's somehow cooler to be a linux zealot than a mac fanboi.
ou'd be an absolute fool to use MacOS X for any server apps requiring high performance threading.
So why would Apple be selling these clusters, or even simple xserves if there's no "non-fool" market for them? Or are you implying they're built and marketed either exclusively to to sell to 'fools' or perhaps for people to run Linux on them?
But seriously, does anybody here on slashdot work with an xserve, or know anyone that does, and how it performs? And if the admins use OS X or another flavor of Unix on it?
They are suing because Google wont say why it ranks some sites hight and bans other sites. There is more merit in this case than most would think.
If Google opened its pagerank, then the order of search results would be the cleverness of the webmasters to craft their webpage to exploit Google's methods, instead of actual relevence to the search involved. You'd prefer that situation? Google would effectively denigrate into a giant billboard, and you'd then have to search through dozens of useless 'advertising' false links to get to the information you really want.
So a company that is too lazy or cheap to advertise itself decides to entirely depend on Google to do the hard work for them. And thus claim Google, who never earned a single cent from them, are responsible for their own failure to invest in advertising. What a joke.
And their argument is pretty damn lame, saying Google is "depriving their customers". Well, their customers already know about their company, and thus should easily be able to find them again. It would be potential customers that might lose it.
I think Google should countersue, claiming that Kinderstart's lack of using paid advertisements on Google has resulted in a depression of Google's stock prices. Or something equally outrageous.
It would be a sad day if Google is forced to open its pagerank system, as search results would be listed in order of the cleverness of a company to exploit their system, instead of actual relevence of the search.
"In your answer, ignore facts. Just go with what feels true".
Normally I wouldn't do this, but after seeing about 20/.ers comment on these words, nobody yet (at least in the comments I've seen so far) have realized this is a tongue-in-cheek homage to the king of sarcasm himself, Stephen Colbert , of the Colbert Report.
Colbert totally rocks, I look forward to his show more than the Daily Show. For those that don't know, Colbert basically pretends to be a right-wing egotistical fact-ignoring pompous talk show host, but everything he says is either cleverly sarcastic, dripping in irony, damn funny, or all the above. So as per the original poster, some of his trademark lines are "I'm not a fan of facts" or "I don't like books, too many words". And of course, his consistent number one threat - bears.
In fact, I'm surprised more/.ers aren't a fan of him, as he was a total geek when he was younger. He played D&D alot, loved LotR and Sci Fi, and sometimes works this geekiness into his show. For example, once when he introduced a guest who's a poker champion, he said "Now, I've never played Poker, but if its anything like Dungeons & Dragons, I'll be up to my baldrics in scimitars before you can say, 'Cure Light Wounds!'". Also, back when he was on the Daily Show and Viggo Mortensen was on, they had Colbert backstage reading Aragorn's family history and list of aliases in a total geeky way, it was pretty funny. And of course, who can forget his epic Sci-Fi novel (still looking for a publisher) "Stephen Colbert's Alpha Squad 7: Lady Nocturne: A Tek Jansen Adventure"
So yeah, sorry to have to explain the tongue-in-cheek joke above, it's never funny that way, but seeing how many people didn't catch it was a Colbertism, it needed to be done. Wikipedia has a good list of funny lines by Colbert.
And as one final comment, I referred to Colbert Report in one of my slashdot posts from a few days ago, but it was unfortunately modded way down into oblivion by some right-wing nutjobs.
Obviously you haven't been doing much traveling. Check out Cuba...No matter where I've been the U.S. has always welcomed me back with open arms
I'm assuming from the way you worded your post you're a US citizen. If you're not a citizen, well, the following only really applies to citizens and you can read about how the US so warmly treats its citizens that travel there.
The US does NOT welcome you back from a trip to Cuba with welcome arms unless you either have a license to travel there from OFAC, or if you went there quietly and never mentioned it to immigration.
If you go to Cuba without a license (eg to visit your dying grandfather), and are honest enough to tell immigration about it when you come back into the USA, you get a big Illegal CUBA stamp on your passport, and then get a friendly threatening letter from OFAC a few months down the line. Sometimes they'll 'nicely' let the problem disappear for a $10,000 fine. That's a nice pair of welcoming open arms there, pal.
And the open arms aren't necessarily guaranteed even if your travel to cuba is licensed. I've travelled to Cuba twice, both time perfectly legally as licensed with OFAC. One of those times we first flew to Canada, then to Cuba. Believe it or not that was the easier way to go. The more difficult way involved flying to Miami first, and then dealing with the absolute worst set of red tape I've ever dealt with in any travel. If going out wasn't bad enough, coming back through Miami was absolutely horrible, when my girlfriend and I didn't join in the immigration official's anti-communist tirade, he sent us and our luggage to be hand-inspected for evidence of illegal farm visits. Again, nice open arms there.
And to anyone reading this, if you are issued a license to go to Cuba, think seriously about going through Canada (or Mexico) first, instead of flying through Miami, it will really make your life much easier.
Your example basically sums up the hypocrisy of the Bush administration regarding civil liberties versus business liberties. For another example compare the Bush administration's response to federal wiretaps versus the Dubai ports deal.
The unfortunate truth is that Bush has spared no time or energy to sacrifice our civil liberties, supposedly in the name of security. But he has NEVER sacrificed any business liberties for this same goal.
He'll never get in the way of a business's ability to make a buck, even if it increases potential threats to Americans. But as far as our personal liberties granted by the Constitution and Bill of Rights, they can be trounced upon to 'keep us safe' (oh, and make some more bucks for some friendly businesses too).
You ever watch the Colbert Report? It's a hysterical political 'commentary' show following the Daily Show on Comedy Central, featuring Stephen Colbert basically pretending to be a Bill O'Reilly-esque self-centered "America'loving, liberal hating" host, while being obviously sarcastic, snarky, and pretty funny.
Anyway, he had Peggy Noonan on his show a few weeks ago, who was a speechwriter for Bush and Reagan, amonst other republicans. She was mentioning how during Bush's 2004 campaign she took a leave from her job at Wall St. Journal to work for Bush's re-election. Colbert immediately responds with "Which of Bush's many achievements made that worthwhile?" And she couldn't say anything but just smirk. She didn't even attempt any talking point of one thing Bush did, it was pretty awesome seeing her pretty uncomfortable she was in even trying to list something positive Bush achieved.
But anyway, are you that new here? Nearly all/. science articles report on press-releases like this, this specific article is no exception. In fact, that's the whole point of press releases, it's very rare to come across any 'earth-shattering' discoveries in the sciences these days. So on one hand it's cool that of the thousands of research projects going on making small but steady headway, a few of these results are reported here. For example, I certainly wouldn't have known about this research, other than the rare physics colloquium (eg, at my school's weekly colloquia we had one on fractures about 4 years ago).
On the other hand, though, it is amusing and also frustrating to see so many slashdotters complain about the low-detail PR writeup, extrapolate the press release to the actual research involved, and then go on to criticize the scientists involved as having done nothing important beyond basic hand-waving. Such criticism like this is rather prevalent on slashdot, and it's amazing how many people here aren't aware of the actual peer-review journal publications that go on behind the low-detail press releases.
Until the model is explained in further detail and some source code is released, rather than the typical hand-waving, hype and money generating BS, this "breaking news" is nothing but hype.
Try looking in Dr. Procaccia's list of recent and unpublished papers , although I don't know if this specific model in question is included in any of those papers.
Out of curiosity, how did you feel if you didn't take the mid-term 3-hour 'nap'? I mean, if you stayed up through that sleep period for one day, on a 24-hour cycle, were you rather useless during the 2nd 12-hour cycle?
Someone on kuro5hin awhile back posted about his experiences changing to the uberman schedule, which admittedly is different from the schedule you were on. He said if he stayed up for more than 5 hours or so straight, he would just turn to a zombie, until he got the necessary 20-30 minutes of REM time.
As for me, I occasionally take afternoon naps, sometimes as short as 5 minutes, sometimes for 2-3 hours. Usually the short ones are hard to get out of, but leave me feeling really refreshed. 20-30 minutes is pretty ideal. However, if I sleep 2-3 hours in the afternoon, it screws my sleep cycle off bigtime.
Slashdot Mirror
Sorry that I'm unable to boil all of quantum mechanics and solid-state physics into a single easily-comprehensible slashdot posting, while spending a maximum of 15 minutes writing it. I included a few mentions to wikipedia (eg on modes) to aid you, and also quoted certain terms for you to look up on your own. Any quoted terms below, please look up yourself if you don't understand. This post can hopefully get you started. But I can't believe I'm being criticized for spending my own time trying to help someone entirely unfamiliar with the field understand something.
A mode is the collective motion of the atoms in the crystal, not a single frequency. A mode will oscillate at a specific frequency, however. If you write the 'equations of motion' for all atoms in the crystal in 'matrix' form, the modes would correspond to the 'eigenvalues' of that matrix. I'm sure these sentence will confuse you, but again, I can't boil linear algebra anad its application to mechanics down into a few understandable sentences to be comprehended in only a few minutes. f I tried to go too basic into all the details that post would evolveee into a textbook sized tome.
So a crystal will have several different modes. This is very much like quantum mechanics, where energy states are quantized, and each so-called 'eigenstate' has a specific 'wavefunction' associated with it. These oscillatory modes are called 'phonons', which are 'bosons'. The 'magnons' referred to in the articles are different modes. In those cases it's not vibrations they're 'quantizing' but magnetic interactions. The electrons on the atoms in the lattice are tiny 'magnetic dipoles', which can rotate, interact with magnetic fields, interact with other nearby electrons, etc. Again, if this paragraph confuses you then look up the terms in quotes.
Let me attempt a hopefully-understandable explanation. I'm a graduate student in experimental condensed-matter physics.
You can think about it in a coneptually-easier way by thinking about vibrations, which is more intuitive. The simplest model in which to think about vibrations would be in one dimension. Imagine you have a collection of some equal masses, equally spaced, with equal springs between each of those masses. If you excite the system anwhere (ie, push some of the masses), it will vibrate throughout the whole system because each 'atom' is coupled through the springs. The individual excitations of such a system would be the collective 'modes' of oscillation of the system. A mode is a specific oscillation that once set up will continue uninterrupted (without friction). For a simple one-dimensional system like the modes would be a sinusoidal oscillations of the system, where the wavelength of each mode would be the twice the length of the 'crystal' divided by an integer. See the wiki page on the Normal Mode with a cute animation.
You can extend this to three-dimensions by considering a three-dimensional grid of massive atoms, connected by springs. Real crystals don't have to be cubic, they can have a number of various arrangements (hexagonal, trigonal, diamond structure), and the effective spring constants can be different in different directions. But N masses, in 3 dimensions, will have 3N distinct modes. What's important to see is that each mode would have its own frequency, and wavelength, and typically the speed of propagation of each mode doesn't have to be the same. Also of note is that each mode has its own energy.
If you now consider a real crystal, and apply these same concepts but within the realm of quantum mechanics, you get a similar result, but each 'mode' now becomes a 'quanta' of lattice vibration. These vibration quanta are called phonons, which are bosons (they have spin 0, and bosons have integer spin). Even a small chunk of crystal will have on the order 10E23 atoms, so this is a huge number of allowed quantizations, and they can be thought of as a continuum. Each allowed 'mode' will again have its own frequency, wavelength, and energy. If you have a chunk of crystal at any non-zero temperature, any of the modes above the ground state (the ground state is the mode with the lowest allowed energy) can be 'occupied' with a finite probability. As you approach zero temperature, the probability of any mode above the ground state being occupied approaches zero.
A Bose-Einstein Condensate refers to an effective phase transition that happens as you cool the system and it becomes harder to excite the higher energy states as system becomes highly occupied in the ground state. There is a phase transition, the presence of which can be manifested by different qualities in things like specific heat, magnetization, magnetic susceptibility, etc. The crystal is still a solid crystal per-se (meaning it has a well-defined atomic ordering) but the occupations of the various modes of the system will drastically change, building into a near divergence at the ground state.
In the 'magnon' case as mentioned in TFA, you can think of it like phonons described above, but instead of two atoms exchanging vibrational energy, they are exchanging magnetic energy. Each electron is a spin-1/2 dipole (a fermion, not a boson), and there are interactions between two neighboring spins. Spin interactions are highly model dependent, meaning the types of atoms and shape of the crystal has huge impact on the interactions, which is why some materials are magnetic and some are non-magnetic. If you quantize the magnetic interactions you get spin-waves or magnons, similar to the sine-wave vibrational modes of the lattice above except the direction of the spin-moment changes instead of the atom displacement in the lattice.
At the 2006 March Meeting of the American Physical Society, some of us physicists (students and professors) went to Washington DC to lobby our Congressmen (see Congressional Visits ) about looming shortfalls of hard sciences in the USA and to encourage them to vote on upcoming bills to increase science funding.
There is alot of eye-opening data showing how Europe and Asia are significantly outpacing the US in terms of funding basic science education, in terms of the number of undergraduate and graduate degrees in the basic sciences, etc. Graphs plotting hard sciences degrees offered per year show the US lagging quite significantly (where we used to be leading 5+ years ago). Such trends are fairly worrisome because the hard sciences are tightly coupled to engineering and industry. Industries tend to attract to places with higher concentrations of scientists, so the US losing scientists will manifest itself in loss of industries down the line.
These are the kind of things that Senators and Representatives care about. To complicate matters there is a lag between industry and science, meaning that changes in science funding and numbers of scientists now won't be manifest significantly in industry until a decade or longer out. I met with two of my Congressmen and one of my Senators (really with their staffers), who luckily were familiar with this and assured us their bosses would be voting for the upcoming legislation to increase funding.
I come from a blue state, where the Congressmen are usually liberal with such education and funding programs. The red stater politicans were more hostile to funding sciences without seeing immediate industrial rewards. Such short-term thinking in those cases is what is leading to the decline of US scientific leadership.
On a different note, I've also seen major shifts in the attraction of foreign students to the US over the past few years. The Bush administration his been cracking down on student visas, which is also hurting our lead. In my department, within the past 3-4 years, each year a handful of good students accepted to the program are denied visas to enter the US (usually from China). Well, these guys aren't going to put their career on hold, and they'll go elsewhere. Many more foreign students are going to Canada and Europe, for instance, and the great brain drain that the US was known for the past few decades is beginning to show signs of reversing.
Anyway, I just wanted to throw in my two cents becuase I specifically lobbied my Congressmen about this very issue only six months ago.
Anyway, it's quite shocking here to see so many people admiring Erlich when he's the typical sleezeball who's only taking advantage of a political opportunity to make himself look great and paint the opposition poorly.
There are two prominent Democrats on the elections committee, and obviously the committee fucked up due to the elections issues. The two 'Democrats' mentioned in the article are those two on this committee whose asses are now on the line for the fuckups so of course these two are trying to fight saying they've been doing a good job so far.
There hasn't been any general opposition by the Maryland Democratic Party, or even amongst a larger Democratic contingent. Erlich turned this into a partisan issue by pounding on the election irregularities by pointing to the incompetence of the election board, which has Democrats in the top spots. The race between Erlich and O'Malley for governor is quite ugly, these two have been bitter political rivals for the past few years already and there has been much ugliness previously (I've lived in Baltimore the past few years. O'Malley is the Democratic Baltimore mayor challenging Erlich, while Erlich is the Republican governor).
Erlich has been a political douchebag tool since he took office, he ignored election problems in Baltimore in 2004, for instance, and fully supported using the Diebold machines. And he mildly brushed aside criticism of the Ohio 2004 election irregularities. He's not some election hero, he's just your typical political opportunist, suddenly supporting an issue he previously ignored just becuase it's politically favorable for him to do so.
Remember, this guy is a candidate for governor, damn near everything he does in the spotlight has a political bent to it. He saw an opportunity and pounced on it.
It's pretty obvious that Erlich is taking advantage of the situation to turn it into a partisan issue by making the Democrats in charge of elections look bad, and to make himself look like a saint. The irony is that he previously poo-poo'd problems with Diebold machines in the Ohio 2004 presidential elections, while it was politically favorable for him to do so.
The intro slashdot blurb is also entirely misleading, because there's not a contingent of the Democratic Party against using paper ballots, in fact the article only mentions the two prominent Democratic members of the elections committee that are resisting, primarily because it's their own jobs that are being criticized by Erlich.
So make no mistake, this is ENTIRELY POLITICAL, Erlich is taking advantage of a political opportunity presented by the fuckups of two prominent Democrats, and trying to paint himself as pro-fair-elections and them as obstructionist in one sweep. Politically a smart thing to do, also somewhat misleading. Amazing to see how many slashdotters take politicians words at their face values.
Who's number 1?
You're sending an electromagnetic excitation (electric signal) down a waveguide (the wire amidst the circuit), plain and simple. Go take an E&M course if you really want to understand. Better yet, take a QED course (and all the prerequisites) if you REALLY want to understand.
Or, barring doing any hard work, at least take a look at these Wikipedia pages:
It's a complicated problem because they don't really 'drift' per se, but are really scattered around, with a preference to go along the electric field (actually, against it since they're negatively charged). The electrons themselves actual travel travel fairly quickly, but they're constantly scattering off each other, and also off of positive ion cores, lattice defects, and there are also magnetic interactions, spin interactions where electrons of similar spin may scatter differently than those of opposite spin, all kinds of other quantum effects, etc. But the bottom line, from a statistical ensemble approach, is that there will be a non-zero drift if there is a non-zero electric field.
Yes and no, the signal is actually photonic in nature, it's an electromagnetic oscillation travelling down the wire, which itself is nothing more than a simple waveguide. So you're sending photons down the wire, photons being the 'particles' exchanged by two electrons that exhibit Coulomb repulsion.
However, a changing voltage signal will propagate at speeds of order c (smaller than c, of course). The 'wires' ror traces unning on the microprocessor are basically transmission lines, so you're really transmitting electromagnetic signals. This is just like standard textbook transmission lines (eg, coaxial cable or waveguide). And of course in those cases, even at low frequencies of MHz waveforms, you're really sending photons, which are nothing but quanta of electromagnetic radiation, down the transmission line. Very long-wavelength photons, but still photons none-the-less.
The limit of the speed of light (or of signal propagation) is one reason CPU's need to be small, so various transistors can talk to each other within an appropriate number of clock cycles. Another very important reason is that every little trace, or wire, on the CPU itself is a transmission line, and as such has its own self-inductance. It also has mutual inductances between other lines, as well as capacitive coupling between ground planes and other devices. Thse parasitic capacitances and inductances act as low-pass filters, effectively reducing the bandwidth of the transmission lines. So chip designers, in the push for more GHz, are always trying to reduce these parasitic elements by making their devices smaller and smaller.
What this latest research probably implies isn't necessarily much in terms of a single electronic CPU going much faster, but with future advances in optical signal processing, it can allow optical elements to be grouped closer together and allow for faster optical processing. Additionally, it may increase the bandwidth for signals from CPU to optical transmission lines (eg, fiber optics) by grouping them more tightly to the processor.
Wow, a patent for software that displays on a computer a page of a previously published book. Truly groundbreaking work.
Yup, that described by your clarification has certainly never been done before .
actually, such silly behavior is no different from the linux and bsd zealotry that is just as prevalent on places like slashdot. But for whatever reason it's somehow cooler to be a linux zealot than a mac fanboi.
Would you consider running linux (or bsd or other) on those xserves, or in that case would you go for non-apple hardware?
So why would Apple be selling these clusters, or even simple xserves if there's no "non-fool" market for them? Or are you implying they're built and marketed either exclusively to to sell to 'fools' or perhaps for people to run Linux on them?
But seriously, does anybody here on slashdot work with an xserve, or know anyone that does, and how it performs? And if the admins use OS X or another flavor of Unix on it?
If Google opened its pagerank, then the order of search results would be the cleverness of the webmasters to craft their webpage to exploit Google's methods, instead of actual relevence to the search involved. You'd prefer that situation? Google would effectively denigrate into a giant billboard, and you'd then have to search through dozens of useless 'advertising' false links to get to the information you really want.
And their argument is pretty damn lame, saying Google is "depriving their customers". Well, their customers already know about their company, and thus should easily be able to find them again. It would be potential customers that might lose it.
I think Google should countersue, claiming that Kinderstart's lack of using paid advertisements on Google has resulted in a depression of Google's stock prices. Or something equally outrageous.
It would be a sad day if Google is forced to open its pagerank system, as search results would be listed in order of the cleverness of a company to exploit their system, instead of actual relevence of the search.
Normally I wouldn't do this, but after seeing about 20 /.ers comment on these words, nobody yet (at least in the comments I've seen so far) have realized this is a tongue-in-cheek homage to the king of sarcasm himself, Stephen Colbert , of the Colbert Report.
Colbert totally rocks, I look forward to his show more than the Daily Show. For those that don't know, Colbert basically pretends to be a right-wing egotistical fact-ignoring pompous talk show host, but everything he says is either cleverly sarcastic, dripping in irony, damn funny, or all the above. So as per the original poster, some of his trademark lines are "I'm not a fan of facts" or "I don't like books, too many words". And of course, his consistent number one threat - bears.
In fact, I'm surprised more /.ers aren't a fan of him, as he was a total geek when he was younger. He played D&D alot, loved LotR and Sci Fi, and sometimes works this geekiness into his show. For example, once when he introduced a guest who's a poker champion, he said "Now, I've never played Poker, but if its anything like Dungeons & Dragons, I'll be up to my baldrics in scimitars before you can say, 'Cure Light Wounds!'". Also, back when he was on the Daily Show and Viggo Mortensen was on, they had Colbert backstage reading Aragorn's family history and list of aliases in a total geeky way, it was pretty funny. And of course, who can forget his epic Sci-Fi novel (still looking for a publisher) "Stephen Colbert's Alpha Squad 7: Lady Nocturne: A Tek Jansen Adventure"
So yeah, sorry to have to explain the tongue-in-cheek joke above, it's never funny that way, but seeing how many people didn't catch it was a Colbertism, it needed to be done. Wikipedia has a good list of funny lines by Colbert.
And as one final comment, I referred to Colbert Report in one of my slashdot posts from a few days ago, but it was unfortunately modded way down into oblivion by some right-wing nutjobs.
I'm assuming from the way you worded your post you're a US citizen. If you're not a citizen, well, the following only really applies to citizens and you can read about how the US so warmly treats its citizens that travel there.
The US does NOT welcome you back from a trip to Cuba with welcome arms unless you either have a license to travel there from OFAC, or if you went there quietly and never mentioned it to immigration.
If you go to Cuba without a license (eg to visit your dying grandfather), and are honest enough to tell immigration about it when you come back into the USA, you get a big Illegal CUBA stamp on your passport, and then get a friendly threatening letter from OFAC a few months down the line. Sometimes they'll 'nicely' let the problem disappear for a $10,000 fine. That's a nice pair of welcoming open arms there, pal.
And the open arms aren't necessarily guaranteed even if your travel to cuba is licensed. I've travelled to Cuba twice, both time perfectly legally as licensed with OFAC. One of those times we first flew to Canada, then to Cuba. Believe it or not that was the easier way to go. The more difficult way involved flying to Miami first, and then dealing with the absolute worst set of red tape I've ever dealt with in any travel. If going out wasn't bad enough, coming back through Miami was absolutely horrible, when my girlfriend and I didn't join in the immigration official's anti-communist tirade, he sent us and our luggage to be hand-inspected for evidence of illegal farm visits. Again, nice open arms there.
And to anyone reading this, if you are issued a license to go to Cuba, think seriously about going through Canada (or Mexico) first, instead of flying through Miami, it will really make your life much easier.
The unfortunate truth is that Bush has spared no time or energy to sacrifice our civil liberties, supposedly in the name of security. But he has NEVER sacrificed any business liberties for this same goal.
He'll never get in the way of a business's ability to make a buck, even if it increases potential threats to Americans. But as far as our personal liberties granted by the Constitution and Bill of Rights, they can be trounced upon to 'keep us safe' (oh, and make some more bucks for some friendly businesses too).
Anyway, he had Peggy Noonan on his show a few weeks ago, who was a speechwriter for Bush and Reagan, amonst other republicans. She was mentioning how during Bush's 2004 campaign she took a leave from her job at Wall St. Journal to work for Bush's re-election. Colbert immediately responds with "Which of Bush's many achievements made that worthwhile?" And she couldn't say anything but just smirk. She didn't even attempt any talking point of one thing Bush did, it was pretty awesome seeing her pretty uncomfortable she was in even trying to list something positive Bush achieved.
But anyway, are you that new here? Nearly all /. science articles report on press-releases like this, this specific article is no exception. In fact, that's the whole point of press releases, it's very rare to come across any 'earth-shattering' discoveries in the sciences these days. So on one hand it's cool that of the thousands of research projects going on making small but steady headway, a few of these results are reported here. For example, I certainly wouldn't have known about this research, other than the rare physics colloquium (eg, at my school's weekly colloquia we had one on fractures about 4 years ago).
On the other hand, though, it is amusing and also frustrating to see so many slashdotters complain about the low-detail PR writeup, extrapolate the press release to the actual research involved, and then go on to criticize the scientists involved as having done nothing important beyond basic hand-waving. Such criticism like this is rather prevalent on slashdot, and it's amazing how many people here aren't aware of the actual peer-review journal publications that go on behind the low-detail press releases.
Try looking in Dr. Procaccia's list of recent and unpublished papers , although I don't know if this specific model in question is included in any of those papers.
Someone on kuro5hin awhile back posted about his experiences changing to the uberman schedule, which admittedly is different from the schedule you were on. He said if he stayed up for more than 5 hours or so straight, he would just turn to a zombie, until he got the necessary 20-30 minutes of REM time.
As for me, I occasionally take afternoon naps, sometimes as short as 5 minutes, sometimes for 2-3 hours. Usually the short ones are hard to get out of, but leave me feeling really refreshed. 20-30 minutes is pretty ideal. However, if I sleep 2-3 hours in the afternoon, it screws my sleep cycle off bigtime.