The research quoted in the article seems completely non-ethical to me. The quote from the article below (SA = Scientific American) below discusses possible short-term, and even long-term memory loss in human subjects. Moreover, it was done in the recent past -- within the past twenty years! How can this be ethical?!
SA: Are there any ways to erase memories by stimulating the brain?
JM: The dominant evidence that goes back over 50 years is that one can block or certainly reduce memories formed within the past several hours by treating human or animal subjects with electro-convulsive shock. But it's nonselective; whatever happened in that past several hours will be gone. And that's rather gross stimulation applied to the skull. What Larry Squire at UC San Diego has shown is that if human subjects are repeatedly given electro-convulsive shocks (several times a week for several weeks), they will have impaired global memory that goes back many months, but that memory will gradually recover. He did this in the late 1980s.
In the way of background, note that Gold is the same Gold of the Bondi-Holye-Gold steady state cosmological model, proposed in the 1940s and 1950s as an attempt to "fix problems" with the big bang model, and has long held non-conventional views on light. Gold and others invoked "tired light" -- photons which became redder from their point of emission, even though doing so contradicted momentum-energy conservation. It's a archetypical example of a theory trashing a fundamental principle in order to exaplain last week's cosmological observations. We should always be wary of our assumptions, but all too often, cosmological theorists will attempt to make a splash by abandoning them in favor of explaining very tenuous and often incorrect observations.
Gold has always been an outsider in the astrophysics community, but has done some very good work over the years; including some seminal work on pulsars. He was Peter Goldreich's (major figure in theoretical astrophysics, for those not familiar) Ph.D. advisor.
Those interested in the history of the steady-state model, including attempts to resurrect it, and the many errors it commits, can check out this page.
Re:Is Thomas Friedman a simplistic hack? * YES *
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Does Google = God?
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· Score: 1
You seem to be under a fundamental misconception.
"His own bias as an American Jew" should not "show through" at all in his reporting.
Note that my original comment applied to his book -- which was devoted to his personal interpretations of Middle-Eastern events, and not his reporting.
His first two Pulitzer prizes were won for hard-nosed reporting in life-threatening warzone conditions. There is a world of difference between the a 200-word news column on the cover the NYT, and its op-ed pages. You are correct that a news column should be completely accurate and balanced, to the smallest detail. By construction, it should not generate controversy. Apparently the people who hand out Pulitzers (who should know a thing or two more about journalism than you) seemed to agree that Friedman's news reporting set the standards for oustanding journalism on two separate occassions.
However, the op-ed pages are a completely different story. They represent a single author's opinion. A good op-ed column should generate thought-provoking discussion and debate, which (as evident from the discussion in this thread and by your own account) is precisely what Friedman's column is doing.
Re:Is Thomas Friedman a simplistic hack?
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Does Google = God?
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· Score: 4, Informative
One thing you must understand about Friedman is that he is a journalist originally schooled in Middle-Eastern studies, who served as a correspondant to Lebanon during the Beirut war, and as a correspondant to Israel during the first Intifadah. These reports earned him two Pulitzer prizes during the 1980s, and are summarized in From Beirut to Jerusalem. Quite simply, it is a excellently-crafted book which has deep insights into the mindsets of the Middle Eastern peoples, developed over years of education and years more direct first-hand reporting experience during some of the most tumultous events in the Middle East in recent history. (Not that the book is without its limitations; many times his own bias as an American Jew shows through. But it is still excellent.)
Since that time, Friedman has been moved out of Middle Eastern reporting, and has gone on to other duties at the NYT. From that reporting came his two most recent books, including The Lexus and the Olive Tree. His insights in these works are not as near as deep as in From Beirut to Jerusalem, and I did not care for them much at all.
However, you are completely off-base if you think that Friedman is a hack. In essenece, you are taking quotes completely out of context, and seem to forget that pages and pages of interpretation and elucidation surround those flashy quotes. To take another example, in From Beirut to Jerusalem, he describes his first-hand witness of the aftermath of the massacre at Hama in Syria, where Assad slaughtered tens of thousands of his own people. (A story he broke, incidentally, as the first international correspondent to arrive at the scene.) In 30 pages of text, he describes in great detail the historical background of modern-day Syria, leading up to the slaughter at Hama, and his own first-hand account of what he saw there. His punchline -- describing the rules of Middle Eastern politics as "Hama Rules" or "no rules at all", is a distinctive stylistic flourish to summarize a concept, based in fact and in interpretation. One may dispute the universality of such claims, but in no way can one dispute the strength of Friedman's knowledge of the history of the region.
When the insight is deep (as is often the case in his writing on the Middle East), then the impact of the writing can be powerful indeed. In the case of his more recent writings, where he is (as he himself admits) writing as a non-expert, the impact is far less substantial.
Every technological innovation since the stone age has had both positive and negative moral aspects, depending on how one uses it. Nuclear physics can be used to diagnose and treat disease (e.g., x-ray, MRI, radiation therapy) and generate electrical power to light up entire cities... or it can be used to obliterate more people in a second than all previous wars combined.
The choice is yours.
So it is not a shame... we must actively look at every innovation, and determine whether the net effect is negative or positive, and whether we wish to regulate its use in society. Cobalt 60 is a great radioative tracer isotope, and can be widely distributed without many negative side effects. The same cannot be said of Uranium 235.
It is unclear how this new innovation will be used , on average. In an age where people are more widely spread apart, often without the commonality of religion and family, it can potentially bring people together into ad-hoc communities. And yes, it can also be used as a tool for stalkers and child molesters. If one significantly outweighs the other, then it will be a useful innovation. If not...
Most of the gas in the universe is supersonic. However, if you are modelling terrestrial atmospheres, or liquid water, as most engineering simulations do, then I agree that you will usually be subsonic.
Yours is just a highly restricted definition of "usually".:-)
This poster is wrong on several accounts, and should be modded down accordingly.
Actually, when you say you did you take a look at the top 500 list, you should put actions behind your words. The top cluster is at #5 on the most recent list (LLNL's NetworX machine - http://www.top500.org/list/2002/11/), and is less than 20% behind the #2 spot. Guaranteed that within a year, linux clusters will indeed fill the #2 spot on down.
Second, hydrodynamic problems (which are a class of hyperbolic PDEs), deal with nothing but local communications, and scale quite well even on Linux clusters. The more challenging set of problems are non-local PDEs (elliptic and parabolic -- like Poisson's equation and heat transfer). Because these problems couple every point in space to every other point in space at ever time, they reamin tough to solve on a parallel machine no matter what platform you are on.
The Earth Simulator is a highly special case. The Japanese government made an enormous investment (well over $500 M) to purchase that machine. Even with the support of the DOE and private industry (increasingly biotech), the US just does not have the political willpower to spend that much on a single platform. It is often neglected that the current paradigms of high-performance computing are lacking in many respects -- some refer to the recent move towards very large parallel machines as "a great step backwards". We have to pursue technically innovative solutions which will be both cheaper to purchase than the Earth Simulator, and more efficient to use.
MIB was not actually the film that made Smith's reputation. It was Six Degrees of Separation. Anyone who has seen that film can testify to the fact that Smith's "Fresh Prince" and MIB images are just the thin veneer on his talent -- the man can act in a serious role as well.
MIT's Technology Review article on the state of high technology in Ghana should be required reading for the original poster, and all those interested in the subject of technology in the third world. The content of the article should give considerable pause to any clueless individual thinking that happily hacking away in their living room is going to substantially impact the living conditions of those living in the third world. While the article points out the immense promise of technology for the third world (one man interviewed had never received a piece of snail mail in his life, but had internet access, and could read news from around the world), that promise largely remains unfulfilled. The author states
Making a telephone call here requires persistence. Roughly half don't go through because of system failures, but that's only the start of Ghana's telephone woes. The country has a mere 240,000 phone lines--for a population of 20 million spread across an area the size of Britain. Moreover, telephone bills are inaccurate, overcharges common, and the installation of a new line can cost a business more than $1,000, the rough equivalent of the annual office rent. Lines are frequently stolen, sometimes with the connivance of employees of Ghana Telecom, the national carrier. Phones go dead, and remain unrepaired, for months. Some businesses hire staff for the chief purpose of dialing numbers until calls go through.
Moreover, even those fortunate enough to have access to the internet find themselves distraught by the knowledge of the incredibly poor conditions in which they must live. One internet cafe owner stated that the majority of users were online in his cafe trying to figure out a way out their country.
The upshot is that much more effort needs to be devoted towards basic infrastructure -- sanitary, transportation, and information -- before an idea like that of the poster's would make much sense.
You are quite right, though you are missing the point.
We can only detect mass indirectly. If there aren't any stars at a given location, astronomers cannot determine the mass of the material interior to that location. (In general, astronomers can also use gaseous emission to infer the central mass, but the principle is the same.) Similarly, if one lacks the resolution to detect stars on such a scale, then one will not be able to make the determination either.
This is a key point.(Although you got a factor of 2 wrong.:-) )
Moreover, your clarification contains the essential answer to one of the original poster's comments. The mean density within the horizon, assuming the region is spherical, is
M / (4 / 3 pi R^3) = M / [4 / 3 pi (2G M / c^2)^3]
= 3 c^6 / (32 pi G^3 M^2)
The key point being that the mean density within the horizon is inversely proportional to the square of the mass of the black hole. For a black hole of 1 solar mass, the mean density within the horizon works out to be amazingly high : of order 10^16 gm/cm^3! On the other hand, for a billion solar mass black hole, this mean density is much, much smaller : of order.01 gm/cm^3.
Another key point is that the masses are not directly detected -- the must be inferred by their gravitational influence on surrounding stars and gas. Observers currently do not have the resolution to probe down to the scale of the horizon, so the argument for a black hole is a compelling one, though not absolutely certain. The masses are not directly detected -- the must be inferred by their gravitational influence on surrounding stars and gas. The primary argument in favor of a black hole is the lack of other possible alternatives. One can prove a strict limit on the mass of a neutron star (which is the most compact stable object known to astrophysics) assuming only causality (ie, that whatever is holding up the neutron star has a sound speed less than the speed of light), is around 5 solar masses. Hence, the most tightly packed situation one could possibly imagine, with the same mass as observed, would be a cluster of several hundred thousand to millions of neutron stars. However, even such a situation is dynamically unstable over many orbits : the neutron stars will tend to form tighter and tighter binaries at the core of the cluster until they merge. Even a single merger would likely create a small seed black hole, which swallow up all the surrounding stars until no matter is left to accrete. So even in this extreme situation, the outcome would eventually be a supermassive black hole. For this reason, the argument for a black hole at the center of our galaxy and others is a very strong one -- if it were a legal case, it would likely hold up in a court of law. However, the absolute proof will require a "smoking gun". Perhaps this will consist of a detection of gas emitting from the accretion disk right around the black hole horizon, carrying with it an absolutely unambiguous signature of the horizon. Or perhaps it may come from gravitational waves radiating at very low frequencies (millihertz or below) -- a telltale sign of the slowly oscillating hole. Such waves will be undetectable from the Earth's surface due to ground noise, and will require a spaceborne mission such as ESA's LISA.
This was very neat, although the concept is by no means new. An artist named Rockne Krebs has been using lasers since the late 1960s to execute new forms of art. Perhaps his most famous art piece was "Green Hypotenuse" (1983) : a massive laser show which beamed an argon laser from the Mt. Wilson Observatory in Pasadena to the wall of the Beckmann Auditorium on the Caltech campus over 7 miles away.
The photograph on a webpage describing the art looks remarkably like the Swedish project. From the webpage:
Rockne Krebs was born in Kansas City, Missouri. In 1961 he received a B.F.A. in sculpture from the University of Kansas. Though not a painter, his fascination with ideas of color, along with his passion for sculpture, spawned a desire to create a sculptural work entirely made of light and color. Eventually this led to his development of "laser sculpture." In 1967 Krebs obtained his first simple HeNe (helium-neon) laser and created the piece Sculpture Minus Object. In 1969 he was sponsored by the Los Angeles County Museum of Art to work with Hewlett-Packard. They collaborated on a design for a piece that Krebs presented in the 1970 World's Fair in Osaka, Japan. This piece featured the first ever laser beam switching system and the prototype of the first laser light show. In 1983, Krebs connected the over 5,000-foot Mt. Wilson to the wall of Caltech's Beckman Auditorium over 7 miles away using light from a single argon laser. He allowed the laser beam to spread so by the time it reached the white exterior of the auditorium it was a constantly changing "painting" of green light. For The Universe: Contemporary Art and the Cosmos Krebs is creating a new piece using lasers and mirrors to connect the Armory building with the park across the street. He is also represented by two drawings, a medium he has explored in depth since the early 1970s.
There are a number of points which need to be made.
First, it takes time to plan out lectures to the extent that they are even worth recording for future generations of students. And time is one resource which most professors do not have. The way academia works today, most professors at major universities are largely occupied by their research activities. Teaching -- especially at the undergraduate level, and most especially at the lower level undergraduate level -- is typically viewed as a nuisance, or at best, a distratction from research. It is quite rare to find a set of lectures worth recording; more often than not, the lectures were prepared in a big hurry the night before or the morning of the lecture. The vast majority of lectures are simply not worth recording in any form.
That said, excellent class materials DO occasionally become available, though typically in print form (as you alluded to). Faculty teaching commonplace courses (for instance, Quantum Mechanics or Statistical Mechanics in physics) whose subject material does not vary much, will often go back to their old notes, polish them up a bit, and have another go at it in a few years. After a few iterations of this process, excellent course notes are often developed. In many cases, those notes find their way into one of those famous textbooks which you have grown to love (or hate!). A great example is the classic "Spacetime Physics" on special relativity, which included questions from actual students taking the first version of the class, along with authoritative answers from John Wheeler, who is one of the world's foremost thinkers on relativity theory, and also one of the best physics teachers who has ever lived.
There are several major implicit assumptions in your statement which I should address. Imagine, for instance, that Feynman, when writing his famed lectures, decided to make then "open". What we would have today, in addition to the original, pristine edition, would be a proliferation of umpteen different versions with comments, additions, and substractions made by other folks. Now, this may come as a shock to you, but the world of ideas is not a democracy. Some ideas are better than others; some thinkers better than others. I submit that Feynman's original version would be vastly superior to almost any modified one; hence, the proliferation of "open" texts, when the best texts by the world's foremost thinkers are already available, would do little good other than to confuse and obfuscate the beginning student. You need to critically examine your assumption that open source dogma is applicable to every conceivable circumstance.
Another huge fact you are missing out on, is that all those great textbooks by the world's greatest thinkers are already at your disposal for free (as in beer). All you need to do is go down to your public library, and check them out! Feynman, Knuth, Plato, Samuelson and others are at your fingertips. If your library does not have a book, just request it through interlibrary loan. This is, in fact, the best of all possible worlds. You really don't want to have to sort through umpteen diluted and distorted "open" versions of those texts.
As someone who grew up during a time when internet access was not commonly available, I find it amusing and alarming that many younger students seem to think they can find anything they wish on the web. Simple point of fact is, those of us who have sat down with the best texts, bugged our profs with questions, did the labs, and thought about things, came through with a much better understanding of basic sciences than those who scanned the web for some writeup by lord-knows-who at Buttfuck U. Again, the world of ideas is not a democracy.
Which brings me to another major assumption in your statement : that one can simply acquire the knowledge one needs by passively sitting back and watching a video or reading a book. In fact, the biggest factor in learning is doing. Working out homeworks. Doing labs. Asking questions in lecture and in sections. This is a really key fact that most beginning students really miss out on; even in introductory courses, there are many challenging concepts which most students fail to absorb. (For instance, how many of you who have taken a basic physic class can explain how a top precesses? Or PRECISELY how the twin paradox works?) Watching another student ask the same questionm may help to some extent, but you will then miss out on another crucial part of learning, which is learning how to ask the right questions. When you boil it all down, learning is essentially an active, participatory experience; you will learn much, much more by becoming actively engaged, rather than just sitting back on your couch and watching a video or reading a book. And you simply cannot do that without lecturers, labs, teaching assistants, and so on. That is why learning at all levels (kindergarten and up) is inevitably so expensive, if done properly.
And the writing in most adventure games is atrocious. The authors were mostly just random programmers with no real creativity or sense of drama. The text of many Sierra games looks like it was written by a half-literate 15-year-old.
No, all this adventure game praising is just false nostalgia. Face it: GTA3 is much more fun than whatever you were playing back then.
Maybe better than the games you were playing back then...
One word... Infocom.
Remember Deadline? Enchanter? Planetfall? Starcross? Infidel? Wishbringer? Among many others? These games had a writing style comparable to good novels. (Not exactly James Joyce, but perhaps to popular authors.)
Comparing those games to GTA is just a joke. Their puzzles were intricately crafted. I recall in Sorcerer, one entered a time travel puzzle on entering a coal mine. You encountered an older version of yourself upon entering the mine, who tells you a combination to a lock in exchange for your spell book. A few minutes later, you find yourself back in the same position as your older self. If you failed to give the book over as your younger self, you would die shortly after leaving the mine. And if you failed to tell your younger self the combination, you would set off a temporal paradox that promptly caused you to cease to exist when your younger self could not unlock the lock. Now, GTA has puzzles and story lines that can compete with that? I think not!
Even if Apple ever were to switch to making x86-based Macs (and you, the reader, are significantly more likely to bang Anna Kournikova than to see an x86-based Mac for sale), they would put something proprietary in those machines, maybe even in every component of those machines, and change the Mac OS to refuse to boot if it doesn't detect that proprietary something.
The "dongle" which some posters have referred to is already in development -- it is called Palladium. In principle, if MS does indeed open the specifications to Palladium, and if Palladium turns out to be a workably secure platform (two big assumptions, which we will make for the sake of argument), Apple could in principle authorize their x86-based OS only on Apple hardware. Somone going out and buying a cheap generic Intel box would not be able to run the Mac OS on it. This would allow Apple to bundle an x86-based hardware box with their OS, while still maintaining a large profit margin. In addition, although the/. crowd may not like to admit the possibility, Palladium DRM may turn out to be quite successful, and may indeed be the only way to (legally) download media from the major media providers in a few years. Running an x86-Mac OS, Palladium-enabled box, will allow Apple to dodge the DRM bullet (more like a cannon shot) as well.
Perhaps Anna will need to prepare for a big/. gangbang...
As a previous poster mentioned, MIT has apologized. I think the huge concern here is not so much that the artwork was plagarized. I mean, what the heck were these folks doing flipping through comic books in preparation for a grant? The fact that they received the grant at all is itself plain scary. How well would an aerospace company competing for a NASA grant fare if they clipped a comic book spaceship and sent it in?
As with any item sold on a free market, the price is set by the supply, relative to the demand. It doesn't matter what the actual item is. A casual inspection of the Antique Roadshow on PBS will give you some indication of this phenomenon to the extreme. Collectors are willing to purchase items (Pez dispensers, teddy bears, 1950s toys) which the bulk of the population might view as near-worthless novelty items for excessive sums of cash. As always, the more limited the number, the higher the price.
In this case, the supply is extremely limited, because one could only purchase a DC BBA for a short period of time, directly from Sega's website. As I recall, they were not even available from Amazon or other retailers. Shortly thereafer, the DC got yanked, and all the BBAs were yanked from production as well. At the same time, while only a very small number of games were ever produced to support broadband, the limited quantity makes them very highly prized items. (ie, We BBA owners love to own yer non-BBA asses in Unreal Tournament. heh.)
Bob
Re:Impact on the environment (and the ground)
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Going Up?
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· Score: 2
Your argument is flawed on two accounts.
First, the weight of the elevator is already set by structural constraints. Static equlibrium demands that a point at the bottom of the elevator must support the weight of the entire elevator above it.
Second, taking a "per kilo" weight analysis is totally bogus when evaluating the total damage. The total weight of the elevator (set by static constraints, not by your analysis) will be absolutely huge, and so the total damage will vastly exceed any conventional or even nuclear device.
Well, I'll tell you something: I'm a CG animator. There'll ALWAYS be a need for actors. We don't just make stuff up out of thin air, we need REFERENCE to know how to make a character do something.
While I agree with you that the poster's original premise was taken to its logical extreme, your logic is also fautly. It is true that the way most animation is done today is by motion capture, but it is also possible to simulate characters entirely digitally. Your implicit assumption is that the way things are done today is the way they will always be done. Put differently, your assertion is that reasonably accurate simulations of human personae is impossible, which I find to be most unlikely. Anyone with enough experience in technology will tell you that what was once thought impossible is now commonplace.
To take a slightly different example, in my work and the work of my colleagues, we simulate the formation of structures in the universe -- clusters of galaxies, molecular clouds, stars -- and in many cases, despite the fact that the simulations never used any input from reality outside of a mathematical model, no human can tell the simulation apart from real astronomical observation.
Clearly, there are several differences from a simulation of gaseous flow and human-like characters. People can move in more complex ways, which is in turn connected to external and internal factors, and so one cannot reduce them to a trivial set of equations of motion. And the human eye is much more attuned to minute differences in facial expression than any other objecct in nature. But at the same time, progress on simulated character animation is being made (having been a research topic in computer graphics for well over twenty years), and sooner or later, it will become almost as accurate as the real thing.
That said, the first photorealistic character will almost certainly be a live actor. Motion capture and voice-overs will handle motion and voice, but the actor will never need to step foot in front of a camera. After that, I imagine it will be possible to simulate the motion and voice of the live actor without having them spend time in the studio. Eventually it will be possible to do, say, a Humphrey Bogart computerized movie which never starred Humphrey Bogart, which all but the most expert observer would be fooled by.
The actual character and object models will still need to be created. But here too, digital models of commonplace objects (houses, chairs, tables, trees, rocks, etc.) as well as famous people (George Bush, Liv Tyler, Ghandi, etc.) will be stored and distributed as stock libraries. You will still need modellers, animators, and programmers to create new objects and new effects, but any amateur director will be able to tell a story using minor alterations of existing libraries. Powerful stories can still be told using this method, as anyone who has ever seen, say, an Indonesian shadow puppet play, can attest to.
The problem here is that you still have cable insteed of digital satellite.
Let's put aside ideology for a second. The plain fact of the matter is that for many purposes, satellite is an inferior technical solution in comparison to cable. Why? Simply because no one will ever be able to break the speed of light limit. Even if I am transmitting a signal to a computer on the other side of town, satellite transmission forces my signal to go all the way up to the satellite... then all the way back down. As a result, the latency involved in a satellite transmission is often vastly greater than ordinary cable, placing severe limits on real-time applications (today -- voice, video, and gaming, and in the future -- telepresence and similar advanced technologies). Cable and satellite become comparable only when a signal must be sent around the globe, in which case the additional transit time to the satellite is not as significant. But the latency costs in that case are so great that no realtime applications of any sort will be practical.
In sum, truly interactive realtime experiences must keep latency limits down below 100 ms or even less. This will NEVER happen with satellite, and will only be practical for signals propapated along the Earth, and even then for relatively nearby portions of the globe.
As technically-minded people, we should never back an inferior technology purely for political reasons. What we should do is encourage political agencies to loosen restrictions on all technologies, so that the broadest field of players can be permitted to compete.
The author of this article has some good technical points. Yes, VCDs are much easier to deal with on older and less expensive hardware. However, he is neglecting a critical issue : where will one get the content in the first place? Although there are thousands upon thousands of active open source projects out there, only a handful have good free written documentation, much less freely available video tutorials! And while there are a handful of oustanding science and mathematics video series ("The Mechanical Universe", "Cosmos", "By the Numbers"), they are almost always owned by the university or broadcast station which produced them.
So, if you are going to distribute video content, either you are going to have to purchase it, or produce it yourself. It doesn't take much to do a quick-and-dirty video shoot with your vidcam in your bedroom with poor lighting and sound, but to really put together an outstanding series like "The Mechanical Universe" takes a lot of time and effort by a lot of talented people. And if you are going to go to all the bother of mass-distributing your video, it absolutely behooves you to do an outstanding job.
So the question remains... where is all this great video content going to come from?
"Cheating is not going to be allowed nor tolerated; if you are caught cheating you are going to be kicked off of the server and your possessions given to the local lord."
Wow! Too bad the US government wasn't running Arianne prior to Enron et al...
Slashdot Mirror
SA: Are there any ways to erase memories by stimulating the brain?
JM: The dominant evidence that goes back over 50 years is that one can block or certainly reduce memories formed within the past several hours by treating human or animal subjects with electro-convulsive shock. But it's nonselective; whatever happened in that past several hours will be gone. And that's rather gross stimulation applied to the skull. What Larry Squire at UC San Diego has shown is that if human subjects are repeatedly given electro-convulsive shocks (several times a week for several weeks), they will have impaired global memory that goes back many months, but that memory will gradually recover. He did this in the late 1980s.
Ummm... this is quite a bit off-topic. That was part of the history of the atomic bomb... the OTHER bomb, and not the hydrogen.
bob
In the way of background, note that Gold is the same Gold of the Bondi-Holye-Gold steady state cosmological model, proposed in the 1940s and 1950s as an attempt to "fix problems" with the big bang model, and has long held non-conventional views on light. Gold and others invoked "tired light" -- photons which became redder from their point of emission, even though doing so contradicted momentum-energy conservation. It's a archetypical example of a theory trashing a fundamental principle in order to exaplain last week's cosmological observations. We should always be wary of our assumptions, but all too often, cosmological theorists will attempt to make a splash by abandoning them in favor of explaining very tenuous and often incorrect observations.
Gold has always been an outsider in the astrophysics community, but has done some very good work over the years; including some seminal work on pulsars. He was Peter Goldreich's (major figure in theoretical astrophysics, for those not familiar) Ph.D. advisor.
Those interested in the history of the steady-state model, including attempts to resurrect it, and the many errors it commits, can check out this page.
"His own bias as an American Jew" should not "show through" at all in his reporting.
Note that my original comment applied to his book -- which was devoted to his personal interpretations of Middle-Eastern events, and not his reporting.
His first two Pulitzer prizes were won for hard-nosed reporting in life-threatening warzone conditions. There is a world of difference between the a 200-word news column on the cover the NYT, and its op-ed pages. You are correct that a news column should be completely accurate and balanced, to the smallest detail. By construction, it should not generate controversy. Apparently the people who hand out Pulitzers (who should know a thing or two more about journalism than you) seemed to agree that Friedman's news reporting set the standards for oustanding journalism on two separate occassions.
However, the op-ed pages are a completely different story. They represent a single author's opinion. A good op-ed column should generate thought-provoking discussion and debate, which (as evident from the discussion in this thread and by your own account) is precisely what Friedman's column is doing.
One thing you must understand about Friedman is that he is a journalist originally schooled in Middle-Eastern studies, who served as a correspondant to Lebanon during the Beirut war, and as a correspondant to Israel during the first Intifadah. These reports earned him two Pulitzer prizes during the 1980s, and are summarized in From Beirut to Jerusalem. Quite simply, it is a excellently-crafted book which has deep insights into the mindsets of the Middle Eastern peoples, developed over years of education and years more direct first-hand reporting experience during some of the most tumultous events in the Middle East in recent history. (Not that the book is without its limitations; many times his own bias as an American Jew shows through. But it is still excellent.)
Since that time, Friedman has been moved out of Middle Eastern reporting, and has gone on to other duties at the NYT. From that reporting came his two most recent books, including The Lexus and the Olive Tree. His insights in these works are not as near as deep as in From Beirut to Jerusalem, and I did not care for them much at all.
However, you are completely off-base if you think that Friedman is a hack. In essenece, you are taking quotes completely out of context, and seem to forget that pages and pages of interpretation and elucidation surround those flashy quotes. To take another example, in From Beirut to Jerusalem, he describes his first-hand witness of the aftermath of the massacre at Hama in Syria, where Assad slaughtered tens of thousands of his own people. (A story he broke, incidentally, as the first international correspondent to arrive at the scene.) In 30 pages of text, he describes in great detail the historical background of modern-day Syria, leading up to the slaughter at Hama, and his own first-hand account of what he saw there. His punchline -- describing the rules of Middle Eastern politics as "Hama Rules" or "no rules at all", is a distinctive stylistic flourish to summarize a concept, based in fact and in interpretation. One may dispute the universality of such claims, but in no way can one dispute the strength of Friedman's knowledge of the history of the region.
When the insight is deep (as is often the case in his writing on the Middle East), then the impact of the writing can be powerful indeed. In the case of his more recent writings, where he is (as he himself admits) writing as a non-expert, the impact is far less substantial.
It's reality.
Every technological innovation since the stone age has had both positive and negative moral aspects, depending on how one uses it. Nuclear physics can be used to diagnose and treat disease (e.g., x-ray, MRI, radiation therapy) and generate electrical power to light up entire cities... or it can be used to obliterate more people in a second than all previous wars combined.
The choice is yours.
So it is not a shame... we must actively look at every innovation, and determine whether the net effect is negative or positive, and whether we wish to regulate its use in society. Cobalt 60 is a great radioative tracer isotope, and can be widely distributed without many negative side effects. The same cannot be said of Uranium 235.
It is unclear how this new innovation will be used , on average. In an age where people are more widely spread apart, often without the commonality of religion and family, it can potentially bring people together into ad-hoc communities. And yes, it can also be used as a tool for stalkers and child molesters. If one significantly outweighs the other, then it will be a useful innovation. If not...
Most of the gas in the universe is supersonic. However, if you are modelling terrestrial atmospheres, or liquid water, as most engineering simulations do, then I agree that you will usually be subsonic.
:-)
Yours is just a highly restricted definition of "usually".
This poster is wrong on several accounts, and should be modded down accordingly.
Actually, when you say you did you take a look at the top 500 list, you should put actions behind your words. The top cluster is at #5 on the most recent list (LLNL's NetworX machine - http://www.top500.org/list/2002/11/), and is less than 20% behind the #2 spot. Guaranteed that within a year, linux clusters will indeed fill the #2 spot on down.
Second, hydrodynamic problems (which are a class of hyperbolic PDEs), deal with nothing but local communications, and scale quite well even on Linux clusters. The more challenging set of problems are non-local PDEs (elliptic and parabolic -- like Poisson's equation and heat transfer). Because these problems couple every point in space to every other point in space at ever time, they reamin tough to solve on a parallel machine no matter what platform you are on.
The Earth Simulator is a highly special case. The Japanese government made an enormous investment (well over $500 M) to purchase that machine. Even with the support of the DOE and private industry (increasingly biotech), the US just does not have the political willpower to spend that much on a single platform. It is often neglected that the current paradigms of high-performance computing are lacking in many respects -- some refer to the recent move towards very large parallel machines as "a great step backwards". We have to pursue technically innovative solutions which will be both cheaper to purchase than the Earth Simulator, and more efficient to use.
MIB was not actually the film that made Smith's reputation. It was Six Degrees of Separation. Anyone who has seen that film can testify to the fact that Smith's "Fresh Prince" and MIB images are just the thin veneer on his talent -- the man can act in a serious role as well.
Bob
MIT's Technology Review article on the state of high technology in Ghana should be required reading for the original poster, and all those interested in the subject of technology in the third world. The content of the article should give considerable pause to any clueless individual thinking that happily hacking away in their living room is going to substantially impact the living conditions of those living in the third world. While the article points out the immense promise of technology for the third world (one man interviewed had never received a piece of snail mail in his life, but had internet access, and could read news from around the world), that promise largely remains unfulfilled. The author states
Making a telephone call here requires persistence. Roughly half don't go through because of system failures, but that's only the start of Ghana's telephone woes. The country has a mere 240,000 phone lines--for a population of 20 million spread across an area the size of Britain. Moreover, telephone bills are inaccurate, overcharges common, and the installation of a new line can cost a business more than $1,000, the rough equivalent of the annual office rent. Lines are frequently stolen, sometimes with the connivance of employees of Ghana Telecom, the national carrier. Phones go dead, and remain unrepaired, for months. Some businesses hire staff for the chief purpose of dialing numbers until calls go through.
Moreover, even those fortunate enough to have access to the internet find themselves distraught by the knowledge of the incredibly poor conditions in which they must live. One internet cafe owner stated that the majority of users were online in his cafe trying to figure out a way out their country.
The upshot is that much more effort needs to be devoted towards basic infrastructure -- sanitary, transportation, and information -- before an idea like that of the poster's would make much sense.
Bob
You are quite right, though you are missing the point.
We can only detect mass indirectly. If there aren't any stars at a given location, astronomers cannot determine the mass of the material interior to that location. (In general, astronomers can also use gaseous emission to infer the central mass, but the principle is the same.) Similarly, if one lacks the resolution to detect stars on such a scale, then one will not be able to make the determination either.
Bob
This is a key point.(Although you got a factor of 2 wrong. :-) )
.01 gm/cm^3.
Moreover, your clarification contains the essential answer to one of the original poster's comments. The mean density within the horizon, assuming the region is spherical, is
M / (4 / 3 pi R^3) = M / [4 / 3 pi (2G M / c^2)^3]
= 3 c^6 / (32 pi G^3 M^2)
The key point being that the mean density within the horizon is inversely proportional to the square of the mass of the black hole. For a black hole of 1 solar mass, the mean density within the horizon works out to be amazingly high : of order 10^16 gm/cm^3! On the other hand, for a billion solar mass black hole, this mean density is much, much smaller : of order
Another key point is that the masses are not directly detected -- the must be inferred by their gravitational influence on surrounding stars and gas. Observers currently do not have the resolution to probe down to the scale of the horizon, so the argument for a black hole is a compelling one, though not absolutely certain. The masses are not directly detected -- the must be inferred by their gravitational influence on surrounding stars and gas. The primary argument in favor of a black hole is the lack of other possible alternatives. One can prove a strict limit on the mass of a neutron star (which is the most compact stable object known to astrophysics) assuming only causality (ie, that whatever is holding up the neutron star has a sound speed less than the speed of light), is around 5 solar masses. Hence, the most tightly packed situation one could possibly imagine, with the same mass as observed, would be a cluster of several hundred thousand to millions of neutron stars. However, even such a situation is dynamically unstable over many orbits : the neutron stars will tend to form tighter and tighter binaries at the core of the cluster until they merge. Even a single merger would likely create a small seed black hole, which swallow up all the surrounding stars until no matter is left to accrete. So even in this extreme situation, the outcome would eventually be a supermassive black hole. For this reason, the argument for a black hole at the center of our galaxy and others is a very strong one -- if it were a legal case, it would likely hold up in a court of law. However, the absolute proof will require a "smoking gun". Perhaps this will consist of a detection of gas emitting from the accretion disk right around the black hole horizon, carrying with it an absolutely unambiguous signature of the horizon. Or perhaps it may come from gravitational waves radiating at very low frequencies (millihertz or below) -- a telltale sign of the slowly oscillating hole. Such waves will be undetectable from the Earth's surface due to ground noise, and will require a spaceborne mission such as ESA's LISA.
Bob
This was very neat, although the concept is by no means new. An artist named Rockne Krebs has been using lasers since the late 1960s to execute new forms of art. Perhaps his most famous art piece was "Green Hypotenuse" (1983) : a massive laser show which beamed an argon laser from the Mt. Wilson Observatory in Pasadena to the wall of the Beckmann Auditorium on the Caltech campus over 7 miles away.
:
The photograph on a webpage describing the art looks remarkably like the Swedish project. From the webpage
Rockne Krebs was born in Kansas City, Missouri. In 1961 he received a B.F.A. in sculpture from the University of Kansas. Though not a painter, his fascination with ideas of color, along with his passion for sculpture, spawned a desire to create a sculptural work entirely made of light and color. Eventually this led to his development of "laser sculpture." In 1967 Krebs obtained his first simple HeNe (helium-neon) laser and created the piece Sculpture Minus Object. In 1969 he was sponsored by the Los Angeles County Museum of Art to work with Hewlett-Packard. They collaborated on a design for a piece that Krebs presented in the 1970 World's Fair in Osaka, Japan. This piece featured the first ever laser beam switching system and the prototype of the first laser light show. In 1983, Krebs connected the over 5,000-foot Mt. Wilson to the wall of Caltech's Beckman Auditorium over 7 miles away using light from a single argon laser. He allowed the laser beam to spread so by the time it reached the white exterior of the auditorium it was a constantly changing "painting" of green light. For The Universe: Contemporary Art and the Cosmos Krebs is creating a new piece using lasers and mirrors to connect the Armory building with the park across the street. He is also represented by two drawings, a medium he has explored in depth since the early 1970s.
There are a number of points which need to be made.
First, it takes time to plan out lectures to the extent that they are even worth recording for future generations of students. And time is one resource which most professors do not have. The way academia works today, most professors at major universities are largely occupied by their research activities. Teaching -- especially at the undergraduate level, and most especially at the lower level undergraduate level -- is typically viewed as a nuisance, or at best, a distratction from research. It is quite rare to find a set of lectures worth recording; more often than not, the lectures were prepared in a big hurry the night before or the morning of the lecture. The vast majority of lectures are simply not worth recording in any form.
That said, excellent class materials DO occasionally become available, though typically in print form (as you alluded to). Faculty teaching commonplace courses (for instance, Quantum Mechanics or Statistical Mechanics in physics) whose subject material does not vary much, will often go back to their old notes, polish them up a bit, and have another go at it in a few years. After a few iterations of this process, excellent course notes are often developed. In many cases, those notes find their way into one of those famous textbooks which you have grown to love (or hate!). A great example is the classic "Spacetime Physics" on special relativity, which included questions from actual students taking the first version of the class, along with authoritative answers from John Wheeler, who is one of the world's foremost thinkers on relativity theory, and also one of the best physics teachers who has ever lived.
There are several major implicit assumptions in your statement which I should address. Imagine, for instance, that Feynman, when writing his famed lectures, decided to make then "open". What we would have today, in addition to the original, pristine edition, would be a proliferation of umpteen different versions with comments, additions, and substractions made by other folks. Now, this may come as a shock to you, but the world of ideas is not a democracy. Some ideas are better than others; some thinkers better than others. I submit that Feynman's original version would be vastly superior to almost any modified one; hence, the proliferation of "open" texts, when the best texts by the world's foremost thinkers are already available, would do little good other than to confuse and obfuscate the beginning student. You need to critically examine your assumption that open source dogma is applicable to every conceivable circumstance.
Another huge fact you are missing out on, is that all those great textbooks by the world's greatest thinkers are already at your disposal for free (as in beer). All you need to do is go down to your public library, and check them out! Feynman, Knuth, Plato, Samuelson and others are at your fingertips. If your library does not have a book, just request it through interlibrary loan. This is, in fact, the best of all possible worlds. You really don't want to have to sort through umpteen diluted and distorted "open" versions of those texts.
As someone who grew up during a time when internet access was not commonly available, I find it amusing and alarming that many younger students seem to think they can find anything they wish on the web. Simple point of fact is, those of us who have sat down with the best texts, bugged our profs with questions, did the labs, and thought about things, came through with a much better understanding of basic sciences than those who scanned the web for some writeup by lord-knows-who at Buttfuck U. Again, the world of ideas is not a democracy.
Which brings me to another major assumption in your statement : that one can simply acquire the knowledge one needs by passively sitting back and watching a video or reading a book. In fact, the biggest factor in learning is doing. Working out homeworks. Doing labs. Asking questions in lecture and in sections. This is a really key fact that most beginning students really miss out on; even in introductory courses, there are many challenging concepts which most students fail to absorb. (For instance, how many of you who have taken a basic physic class can explain how a top precesses? Or PRECISELY how the twin paradox works?) Watching another student ask the same questionm may help to some extent, but you will then miss out on another crucial part of learning, which is learning how to ask the right questions. When you boil it all down, learning is essentially an active, participatory experience; you will learn much, much more by becoming actively engaged, rather than just sitting back on your couch and watching a video or reading a book. And you simply cannot do that without lecturers, labs, teaching assistants, and so on. That is why learning at all levels (kindergarten and up) is inevitably so expensive, if done properly.
Bob
Johnny Mnemonic
'nuff said
And the writing in most adventure games is atrocious. The authors were mostly just random programmers with no real creativity or sense of drama. The text of many Sierra games looks like it was written by a half-literate 15-year-old.
No, all this adventure game praising is just false nostalgia. Face it: GTA3 is much more fun than whatever you were playing back then.
Maybe better than the games you were playing back then...
One word... Infocom.
Remember Deadline? Enchanter? Planetfall? Starcross? Infidel? Wishbringer? Among many others?
These games had a writing style comparable to good novels. (Not exactly James Joyce, but perhaps to popular authors.)
Comparing those games to GTA is just a joke. Their puzzles were intricately crafted. I recall in Sorcerer, one entered a time travel puzzle on entering a coal mine. You encountered an older version of yourself upon entering the mine, who tells you a combination to a lock in exchange for your spell book. A few minutes later, you find yourself back in the same position as your older self. If you failed to give the book over as your younger self, you would die shortly after leaving the mine. And if you failed to tell your younger self the combination, you would set off a temporal paradox that promptly caused you to cease to exist when your younger self could not unlock the lock. Now, GTA has puzzles and story lines that can compete with that? I think not!
Bob
Interestingly enough, I predicted essentially this same technique during an earlier discussion on the nanotechnology nanotechnology defense initiative at MIT.
/. ;-)
A key example of how life imitates
Bob
Even if Apple ever were to switch to making x86-based Macs (and you, the reader, are significantly more likely to bang Anna Kournikova than to see an x86-based Mac for sale), they would put something proprietary in those machines, maybe even in every component of those machines, and change the Mac OS to refuse to boot if it doesn't detect that proprietary something.
/. crowd may not like to admit the possibility, Palladium DRM may turn out to be quite successful, and may indeed be the only way to (legally) download media from the major media providers in a few years. Running an x86-Mac OS, Palladium-enabled box, will allow Apple to dodge the DRM bullet (more like a cannon shot) as well.
/. gangbang...
The "dongle" which some posters have referred to is already in development -- it is called Palladium. In principle, if MS does indeed open the specifications to Palladium, and if Palladium turns out to be a workably secure platform (two big assumptions, which we will make for the sake of argument), Apple could in principle authorize their x86-based OS only on Apple hardware. Somone going out and buying a cheap generic Intel box would not be able to run the Mac OS on it. This would allow Apple to bundle an x86-based hardware box with their OS, while still maintaining a large profit margin. In addition, although the
Perhaps Anna will need to prepare for a big
Bob
The original MIT press release was covered a few months back in /. :
Original slashdot post
As a previous poster mentioned, MIT has apologized. I think the huge concern here is not so much that the artwork was plagarized. I mean, what the heck were these folks doing flipping through comic books in preparation for a grant? The fact that they received the grant at all is itself plain scary. How well would an aerospace company competing for a NASA grant fare if they clipped a comic book spaceship and sent it in?
Bob
As with any item sold on a free market, the price is set by the supply, relative to the demand. It doesn't matter what the actual item is. A casual inspection of the Antique Roadshow on PBS will give you some indication of this phenomenon to the extreme. Collectors are willing to purchase items (Pez dispensers, teddy bears, 1950s toys) which the bulk of the population might view as near-worthless novelty items for excessive sums of cash. As always, the more limited the number, the higher the price.
In this case, the supply is extremely limited, because one could only purchase a DC BBA for a short period of time, directly from Sega's website. As I recall, they were not even available from Amazon or other retailers. Shortly thereafer, the DC got yanked, and all the BBAs were yanked from production as well. At the same time, while only a very small number of games were ever produced to support broadband, the limited quantity makes them very highly prized items. (ie, We BBA owners love to own yer non-BBA asses in Unreal Tournament. heh.)
Bob
Your argument is flawed on two accounts.
First, the weight of the elevator is already set by structural constraints. Static equlibrium demands that a point at the bottom of the elevator must support the weight of the entire elevator above it.
Second, taking a "per kilo" weight analysis is totally bogus when evaluating the total damage. The total weight of the elevator (set by static constraints, not by your analysis) will be absolutely huge, and so the total damage will vastly exceed any conventional or even nuclear device.
Bob
Well, I'll tell you something: I'm a CG animator. There'll ALWAYS be a need for actors. We don't just make stuff up out of thin air, we need REFERENCE to know how to make a character do something.
While I agree with you that the poster's original premise was taken to its logical extreme, your logic is also fautly. It is true that the way most animation is done today is by motion capture, but it is also possible to simulate characters entirely digitally. Your implicit assumption is that the way things are done today is the way they will always be done. Put differently, your assertion is that reasonably accurate simulations of human personae is impossible, which I find to be most unlikely. Anyone with enough experience in technology will tell you that what was once thought impossible is now commonplace.
To take a slightly different example, in my work and the work of my colleagues, we simulate the formation of structures in the universe -- clusters of galaxies, molecular clouds, stars -- and in many cases, despite the fact that the simulations never used any input from reality outside of a mathematical model, no human can tell the simulation apart from real astronomical observation.
Clearly, there are several differences from a simulation of gaseous flow and human-like characters. People can move in more complex ways, which is in turn connected to external and internal factors, and so one cannot reduce them to a trivial set of equations of motion. And the human eye is much more attuned to minute differences in facial expression than any other objecct in nature. But at the same time, progress on simulated character animation is being made (having been a research topic in computer graphics for well over twenty years), and sooner or later, it will become almost as accurate as the real thing.
That said, the first photorealistic character will almost certainly be a live actor. Motion capture and voice-overs will handle motion and voice, but the actor will never need to step foot in front of a camera. After that, I imagine it will be possible to simulate the motion and voice of the live actor without having them spend time in the studio. Eventually it will be possible to do, say, a Humphrey Bogart computerized movie which never starred Humphrey Bogart, which all but the most expert observer would be fooled by.
The actual character and object models will still need to be created. But here too, digital models of commonplace objects (houses, chairs, tables, trees, rocks, etc.) as well as famous people (George Bush, Liv Tyler, Ghandi, etc.) will be stored and distributed as stock libraries. You will still need modellers, animators, and programmers to create new objects and new effects, but any amateur director will be able to tell a story using minor alterations of existing libraries. Powerful stories can still be told using this method, as anyone who has ever seen, say, an Indonesian shadow puppet play, can attest to.
Bob
The problem here is that you still have cable insteed of digital satellite.
Let's put aside ideology for a second. The plain fact of the matter is that for many purposes, satellite is an inferior technical solution in comparison to cable. Why? Simply because no one will ever be able to break the speed of light limit. Even if I am transmitting a signal to a computer on the other side of town, satellite transmission forces my signal to go all the way up to the satellite... then all the way back down. As a result, the latency involved in a satellite transmission is often vastly greater than ordinary cable, placing severe limits on real-time applications (today -- voice, video, and gaming, and in the future -- telepresence and similar advanced technologies). Cable and satellite become comparable only when a signal must be sent around the globe, in which case the additional transit time to the satellite is not as significant. But the latency costs in that case are so great that no realtime applications of any sort will be practical.
In sum, truly interactive realtime experiences must keep latency limits down below 100 ms or even less. This will NEVER happen with satellite, and will only be practical for signals propapated along the Earth, and even then for relatively nearby portions of the globe.
As technically-minded people, we should never back an inferior technology purely for political reasons. What we should do is encourage political agencies to loosen restrictions on all technologies, so that the broadest field of players can be permitted to compete.
Bob
The author of this article has some good technical points. Yes, VCDs are much easier to deal with on older and less expensive hardware. However, he is neglecting a critical issue : where will one get the content in the first place? Although there are thousands upon thousands of active open source projects out there, only a handful have good free written documentation, much less freely available video tutorials! And while there are a handful of oustanding science and mathematics video series ("The Mechanical Universe", "Cosmos", "By the Numbers"), they are almost always owned by the university or broadcast station which produced them.
So, if you are going to distribute video content, either you are going to have to purchase it, or produce it yourself. It doesn't take much to do a quick-and-dirty video shoot with your vidcam in your bedroom with poor lighting and sound, but to really put together an outstanding series like "The Mechanical Universe" takes a lot of time and effort by a lot of talented people. And if you are going to go to all the bother of mass-distributing your video, it absolutely behooves you to do an outstanding job.
So the question remains... where is all this great video content going to come from?
Bob
"Cheating is not going to be allowed nor tolerated; if you are caught cheating you are going to be kicked off of the server and your possessions given to the local lord."
Wow! Too bad the US government wasn't running Arianne prior to Enron et al...