Several other people have pointed out that hydrogen has value as a means of transmission of power that makes it a useful step in the transition toward complete reliance upon indefinitely sustainable energy sources. Hydrogen/solar and hydrogen/wind are natural combinations, as both sun and wind are abundant resources that often aren't co-located with high densities of energy consumers.
But it gets better.
Hydrogen as a transport medium has three big advantages over electricity: transmission is relatively lossless, hydrogen can be stored far more easily than electricity, and hydrogen is better suited to powering small mobile engines, such as those found in automobiles. On the first point, roughly 40% of electricity generated in Canada (admittedly a worst case) goes into line losses. The number in the U.S. isn't that much lower. Ergo, hydrogen production can be moderately inefficient compared to simple electricity generation and still break even on efficiency grounds.
Most importantly, however, cars that use hydrogen generated from burning coal, oil or gas would be far more energy-efficient and less poluting of the atmosphere than gasoline powered automobiles. The reason for this is simply that large stationary power-plants are much easier to load with all kinds of fancy efficiency-enhancing, polution-reducing technology than cars are. Small, mobile power plants suffer from all kinds of practical engineering constraints (weight, size, cycle-of-use,...) that don't affect big stationary power plants.
I read this book a while back, and was really impressed by it. It is probably the best book on "the golden age of piracy" I've encountered--much better than Johnson's.. err.. Defoe's.. err.. whoever's.."General History" and vastly more readable than the (admitedly more scholarly) "Under the Black Flag" by David Cordingly.
"Pirate Hunter" is much more than a biography of Kidd--it is a vivid re-creation of the life and society of European pirates at the turn of the 18th century.
It also contains food for thought for techies who think that if they do a good job they'll be rewarded for it. The contrast beween Kidd, who believed himself innocent, trusted the system, and was hanged; and Robert Culliford, who believed himself guilty, worked the system, and walked free, is an object lesson to all virtuous people.
If Kidd had understood the veniality of the majority of nominally decent people whom he dealt with he might still be alive today.
Isn't it interesting that when women die or have poor health it's viewed as a societal problem and when men die or have poor health it's viewed as our own damned fault?
Men die because our lives are less valued than women's, and we are brought up to value our lives less. We are surrounded by cultural propoganda dedicated to the proposition that the gruesome death of a young man is, literally, glorious.
Until we value the lives of men as highly as we value the lives of women, men's lives will continue to be shorter and poorer than women's.
The data reported in this study contain many subtle cues as to how men routinely mistreat themselves: for example, men take fewer disability days than women. This is not because men suffer from fewer hurts and harms, but because we are taught from birth that it's more important to sacrifice ourselves than take to care of ourselves. And sacrifice ourselves we do.
As near as I can figure, this has nothing to do with websites and everything to do with website names. Websites are collections of information, much like books.
The articles says that the U.S. government has put website names on the list of aliases for terrorist organizations, but this does not mean the websites are in any sense terrorist organizations, any more than a book can be a terrorist organization.
For example, it would make no sense at all for the government to say: "We have placed the following books on our list of terrorist organizations: MEIN KAMPF, THE COMMUNIST MANIFESTO, THE PROTOCOLS OF THE ELDERS OF ZION, THE OXFORD ENGLISH DICTIONARY and THE FARMER's ALMANAC."
I use the OED and THE FARMER'S ALMANAC as examples because they are books that are also ongoing projects by identifiable organizations. But the books are not the organizations--they are merely a name under which the organization may be identified.
This is an important distinction because of course only someone inexcusably ignorant of history would want the goverment censoring websites. Noting that website (or book) names may be used as aliases for terrorist organizations, however, is quite a different kettle of herring.
Good teaching at Cambridge in Newton's day was a even rarer than today. Most professors treated their positions as sinecures, and many didn't do any teaching at all. Westfall's definitive biography of Newton, NEVER AT REST, treats this in detail. So Newton was not atypical in this regard.
With regard to publication and scientific journals, the Royal Society, whose Proceedings can be considered the prototype for the modern scientific journal, was founded in 1640 or thereabouts, and there were similar foreign publications, so scientific journals did exist.
Newton published very little prior to the Prncipia because he got irritated by negative response to his work, and felt he wasted far too much time arguing with people about it.
For example one paper he published described some optical work in which he mentioned that the spectrum from a prism was linear, which ran counter to the prevailing belief that it was circular (empiricism was still very much in its infancy). He was attacked for this claim, even by people who took the trouble to look at such spectra themselves but who saw circles because that is what they expected to see.
Finally, Newton did not publish Principia primarily to further his fights with Leibniz and Hooke, which occupied him much more after the publication of the Principia than before. He published it, famously, at the behest of his friend Edmund Halley, who felt that the results were too important to go unpublished. Self-agrandizement also surely played a role, but it is extremely doubtful it was the primary cause.
Newton was a complex character, subject to fits of melancholy and maddness. In later life he was frequently described as charming--wealth, fame and power probably improved his disposition more than a little.
Given his natural abilities, he would almost certainly find himself a faculty position today at the school of his choice, as modern universities are at least as welcoming to poor but capable students as they were in Newton's day, and being socially disfunctional has rarely been a bar to academic appointment.
Yes. I had the same thought. I'm sure others have as well. I kind of took it for granted that the SCO moves are a part of a broad-scale intentional attack on Open Source and Free Software, encouraged and funded at least in part by You Know Who.
I doubt there is a very high degree of deliberate co-ordination between parties--it's just matter of spontaneous organization, rather like the 'Net itself.
Microsoft et al must know they are doomed to become a software services company in time. Economics 101 tells us that the equilibrium market value of a good whose incremental cost of production is zero, is zero. This is exactly the situation with a mature software product. A software release that fulfills customer needs has a (nearly) zero incremental cost of production: the cost of producing the next unit is the cost of downloading.
Only when feature sets are still in flux is there any money to be made in software. As feature sets stablize (think office suites) free alternatives will catch up in functionality to commercial offerings (think OpenOffice.org). This is a cumulative process that will eventually bury most commerical software houses, whose best bet will be to become service organizations. This transition is already well underway at places like IBM.
Short-term IP protection, particularly patents, can preserve some value for commerical software, and I expect we'll see lots more attempts to exploit this path to continued economic viability simply because the profit margins on software products are stupendous compared to those on software services, particularly when you own a monopoly in a niche.
So long as the Open Source and Free Software communities exist, commercial software will be under threat. It follows from this that the major interest of commercial software vendors at this time is to gain legal protection from the OS/FS community. Once upon a time commerical software could plausibly (if not always accurately) claim technological superiority. Then it could claim superior support (less plausibly and much less accurately)--people still try this with the "total cost of ownership" argument, but it becomes less defensible on empirical grounds as time passes and more and more organizations opt for OS/FS because it really is cheaper and better supported.
The next frontier in the software industry is legal, not technological, and most of the major battles in the next decade will be fought in the courts, with all of us nerds sitting on the sidelines thinking, "I remember when technology was the stuff that mattered."
Even if you use small amplitudes or an almost ideal cantilever, the cantilever is still part of a bigger system with a thermal source (the outside, infinite degrees of freedom, yaddy yaddy yadda). My questions is not only considering thermal exchange, but also just the fact of leaking the wave fuction of the cantilever to "the outside".
The note in Nature says they're going to keep everything very cold, which addresses this problem. Cooling can be viewed as "pumping away degrees of freedom", at least in a quantum solid where a given mode becomes exponentially unavailable below its excitation energy.
If simply being in contact with something that was connected with the warm, mode-rich outside world via a cooling apparatus was a problem for an experiment like this, then it would also be a problem for superposition experiments with superfluids and superconductors. Given that cooling solves the problem in those cases, it will solve the problem in this case as well.
The hard part of doing QM effects on cats (big systems) is that it gets harder and harder to close the system to the rest of the universe.
I believe the more important effect is that cats (complex systems) have many modes themselves, which are strongly coupled to each other, so that that any effect that depends on the long-term or long-range coherence of any given mode (i.e. any quantum effect) is obliterated. My own cat, Yogurt, is trying to help me type this, and he agrees with me.
There are in fact many dark matter problems. This work deals with galactic dark matter only, which could be solved by normal matter. This is not the case for dark matter problems on larger scales.
On scales larger than galaxies, we can see that galaxies and groups of galaxies appear affected by stronger gravitational forces than can be accounted for by visible matter, and on very large scales it appears that there is more gravity than can be accounted for by ordinary matter, period.
There are strict limits on the amount of ordinary (baryonic) matter that come from primordial nucleo-synthesis. In the early seconds after the Big Bang, the quark-gluon plasma cooled down to form baryons (protons and neutrons, to you.) Eventually (some seconds or minutes later) the baryons cooled down to the point where their average energy was low enough that when they ran into each other they tended to stick together rather than flying apart again.
The nuclei formed in these early times were: hydrogen (single protons), deuterium (p+n), 3He (p+n+n), 4He (p+p+n+n) and tiny amounts of lithium and above. As you can imagine, the ratios of hydrogen to everything else are critically dependent on the density of neutrons at the time these nuclei were forming: the more neutrons, the more heavy nuclei. We can infer from observations on stars fromed shortly (~millions of years) after the Big Bang what these ratios were, which tells us the density of neutrons and protons at that time. We also know the volume (curvature) of the universe at that time, and so can infer the total number of baryons in the universe.
There are not enough baryons to account for the gravitational (or gravity-like) forces acting at the largest observable scales. Ergo, something else is happening (or the observations are wrong, which is always a possibility.)
Given the number of dark matter problems, it is unlikely that one particle will solve them all, and quite possible that we are seeing the effects of quite different causes at different scales. This should not be a surprise. For example, we already see very different causes at nuclear scales vs. atomic scales vs planetary scales. It is possible that on galactic and size-of-the-universe scales different causes are at work as well, either due to hitherto undiscovered forces or equally unknown particles.
This is a good point, but I'm sure the researchers have considered it. The limiting factor will be inelastic flexion of the cantilever, which can be made small in a number of ways, not least of which is keeping the amplitude of vibration small. Given that they're talking about setting the thing vibrating using the momentum transfer from a single photon, this shouldn't be a huge problem!
But it does bring up an important common misunderstanding that the headline of the article repeats: quantum effects have absolutely nothing to do with size and everything to do with complexity. A photon that passes through both slits of a double-slit apparatus demonstrates quantum effects on a scale of a fraction of a millimeter (the separation distance of the slits) and large multi-path interferometers of one kind or another involve photons that take paths that are tens of centimeters or more apart.
Size doesn't matter. What matters is the number of modes available, because interference between modes destroys our ability to observe quantum effects. Systems of many particles (particularly at higher temperatures) have so many modes available that the coherence time is extremely small, although even then we can under the right circumstances observe things like the Mossbauer Effect in which an entire block of material acts as a single quantum-mechanical entity.
This article is mostly dead-on, but misses the mark in two respects on the loyalty question.
In the first place, it's wrong to say that companies are loyal to their Boards of Directors, or shareholders. The fact is that companies are loyal to nothing whatsoever, except possibly to the neurotic personal needs of their executives and managers. If companies were loyal to their boards or shareholders we wouldn't see the gross mis-management and poor corporate governance that is all too common.
In the second place, employees should not just not be loyal, they should be actively disloyal, in the sense that every employee should be in the job market all the time. Seriously.
That means keeping your resume up-to-date, and reading the job ads in your field (print and on-line) regularly. If you see something that looks particularly interesting, don't be shy about applying for it, and if you get an interview go for it. It'll keep your interview skills in shape, and you never know--it might be your dream job. Don't worry about wasting anyone's time: as mentioned by other posters, companies advertise jobs they have no intention of filling, so turn-about is fair play.
Furthermore, you should be fairly up-front with your current employer about this attitude after you've been with them for a year or so. You don't have to make a big deal of it--just mention casually now and then that you've seen that Company X is hiring (it helps if Company X is a well-known competitor, as your boss won't know if you're keen and keeping an eye on the market or thinking of jumping ship.)
No matter who you work for, you are your own boss. You are the only boss who will ever care about your career, your goals, your well-being or the well-being of your family.
After moving into the tech world from academia seven years ago, I've had five jobs. I jumped ship twice, companies folded twice, and I'm currently running my own business after a period of unemployment resulting from the last company folding, so I know whereof I speak. Both as a developer and a manager I pursued the policy I've outlined above.
As a manager, I encouraged members of my team to do the same--I wanted them to be able to walk in the door in the morning and ask, "What has the company done for me lately?" and be able to find an answer that would motivate them to work hard and well, which they did. Of course, part of the answer to that question is always, "Paid my salary", which is important to keep in mind.
Senior management, of course, did not like my attitude--amongst other things, they were unhappy that I insisted that every member of the development team actually take all the accrued vacation owing to them! But so long as my team kept mysteriously producing outstanding results they had to put up with it.
And equally unsurprisingly, those outstanding results did not stop half my team from being laid off (over my objections) a few months prior to the company folding up.
If this person was a writer/researcher/whatever for a company, and he made comments that were not only attributed to him, as an individual, but to the company he worked for- yes, they can get rid of him.
What part of "the views of the authors are theirs and theirs alone" don't you understand?
This design may account for the fairly astonishing efficiency claims, as well: the light is getting focussed onto a small area, and the chips will be running at very high temperatures.
Despite the complex quantum-mechanical nature of photovoltaic conversion, there are still underlying thermodynamic limits, and to an extent they can be treated as heat engines running between 6000 K (the surface temperature of the sun) and 300 K (the surface temperature of the Earth), which gives theoretical (Carnot) efficiencies ~90%.
Good over-views are available on the web.
Focussing or concentrating sunlight should make it easier to reach something close to this efficiency in practice.
That said, these suckers are going to have lots of moving parts (phased arrays, anyone?) and it's likely to be a while before we are buying them at Home Despot. And as an earlier poster pointed out, turning off the lights (just putting light switches where ordinary employees can turn off the lights!) is going to save us far more energy in the short term than anything else.
Of course, a good way to encourage people to save energy would be to create a market which could price energy appropriately given the level of supply and demand, rather than running about in a panic and capping the price every time it looks like consumers might actually notice the bite their energy bills are taking out of their bank account.
1) The argument that "the Japanese didn't have a great industrial infrastructure" and therefore an invasion of mainland Japan would have been relatively bloodless does not hold water. To name just a couple of nations that had even less industrial infrastructure than Japan circa 1945: Afgahnistan in the '80's and Vietnam in the '70's. Ill-equiped local forces fighting "the little war" have for centuries proven to be formidable enemies to technologically superior foreign invaders.
2) Total victory was a political, not a military requirement, and it was justified by reference to the unsatisfactory outcome of "technical victory" in WWI. It was a widely and plausibly held view that anything short of total victory would result in another world war in 25 years, just like the last time.
It is always easy to solve problems we never had--the invasion of mainland Japan, or the creation of a lasting peace after a "technical victory" over an unconquered enemy. But we know with certainty from similar cases that those scenarios would play out with at least as much bloodshed and horror as we actually had.
Not if you're making helium from deuterium, there aren't - you get them in hot fusion where tritium is being used (there are spare neutrons to go round), but 2 deuterium nuclei will make 1 helium-4 nucleus + energy.
And the 4-He will in fact get most of that energy, which will make it move so fast that it will knock neutrons off deuterium nuclei (and other nuclei) while slowing down. If the 4He doesn't get the energy, it must come out in gamma rays (ignoring inadequate coupling constants for a moment--we're doing phictional physics here).
Neither neutrons nor gamma rays are observed. Nor, for that matter, is 4He.
It was a 17 keV neutrino, and neither it nor the fifth force deserve to be in this list. Both were valid (if somewhat over-enthusiastic) interpretations of experiments that were carried out with good technique.
The 17 keV neutrino in particular showed up in both Simpson's tritium spectra and in 14-C measurements made a Berkeley. It was that latter measurements that made most of us take notice.
The first experiments that failed to see the 17 keV neutrino were not as rigorous as one would like, and Simpson was in my view justified in his criticisms. 2nd generation experiments, such as my own measurement on 35-S, were done more carefully in consequence, and the scientific community had relatively little trouble coming to concensus that there ain't no 17 keV. Even Simpson and Hime agree with this, and no one thinks that they were anything but unlucky.
Cold fusion is not like this. Those who claim positive results can't come up with a consistent universe of phenomena that requires explaining, and they continually promise definitive results "real soon now" and have been for a decade or more.
"Dressing up" became the norm (that is, for normal people, as opposed to the extremely rich or aristocratic people) about two hundred years ago, when industrial technology made cheap clothing available to the normal people.
Many of them also which used curious arts brought their books together, and burned them before all [men]: and they counted the price of them, and found [it] fifty thousand [pieces] of silver.
One can argue about the specific direction a Christian should take from this (should you burn only your own books or other people's too?) but there is no doubt that book burning has been seen as something of value to Christians from very nearly the beginning. The books described in Acts were probably arcana of various kinds, primarily judicial astrology and the like. To a Christian many of the books in the Royal Library would have fallen into the same category.
I don't believe that Christians were responsible for burning the Royal Library at Alexandria. But they have certainly been responsible for burning many other books--in Alexandria and elsewhere--over the past 2000 years. They have no monopoly on this behavior, though: book-burning is one of the pass-times that all tyrants, religious or secular, engage in.
To pose the question of the burning of large collections of books in Alexandria as an either-or is to forget that, given how long Alexandria has been a center of learning, there have been more than enough books there for everyone to have their fair share of burnings, hatred and destruction.
Pompeii and Herculaneum were something akin to the Las Vegas of Rome.
Pornography is a basic metric of human economic well-being. In any society with sufficient wealth porn and prostitution are rapidly industrialized, often preying on the least advantaged members of society to the benefit of the most advantaged.
This was as true in Rome 2000 years ago as it is in America (or Tailand) today.
However, there are better ways of making 3-He (a major source today is tritium decay, tritium being bi-product of heavy water reactors.) And the very fact that a small amount of 3-He can make a large amount of energy means that you don't need to produce huge amounts of 3-He to run fusion reactors on it.
Ergo, it is unlikely to be a major factor in space exploration. Unfortunately the simple extraction of raw materials is not likely to ever be sufficient to justify space exploration on a commercial basis. Natural resources are not likely to ever again be a major economic driver: intelligent use of resources, including recyling, is almost always a better investment.
On the other hand, the more efficiently we use resources (which incidently means the less polution we create) the wealthier we will be, and therefore the more exotic vacation location we'll be able to visit...
Aspect-oriented programming has been talked about for a while now, but it still isn't nearly ready for prime time. The obvious issues are that it will introduce bugs and that it will be at the same time very hard to debug.
The first goes without saying: every new technique can be considered a collection of novel ways that things can go wrong. Insofar as AOP is powerful, it will create whole new classes of bugs.
Things like AspectJ make things worse, though, because they are pre-processors. So debugging is going to involve tracing into machine-generated code. This does not need to be a nightmare, but somehow it almost always is.
There is also the issue of debugging your aspect specifications themselves, alluded to briefly in the article with the point about infinite recursion. I'm sure there are many other subtle and interesting bugs that AOP can introduce, and I'm very grateful to all the eager souls who are going to find and fix them over the next few years.
I think AOP solves a legitimate problem. I'm not by any means sure it's the best solution. In a few more years, when tools and techinques have matured a little, it may prove to be a valuable technique.
--Tom
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I had 4 direct friends of mine who commited suicide and a hell of a lot other people who I knew commited suicide also.
And they were all boys, right?
Suicide amongst young people is dominated by suicide amongst boys.
Another important reason for scaling up is that the dominant loss terms scale as the surface area of the plasma, whereas (theoretical) output power scales as the density. So larger volumes have smaller relative losses.
This is actually one of the impediments to commercial fusion power: reactors efficient enough to generate commerical power will have to be big, which is a problem because "big" translates to "takes a long time to build" and no one knows what the demand for power will be two years from now, much less ten or fifteen.
Getting capital together for such a project won't be easy, and there are only a few locations where a 20 GW plant makes any kind of sense.
So the economic problems faced by the fusion power industry will be a large multiple of those faced by the fission power industry.
See for example Newton Timeline. Note the item for 1697, when Newton was 55. He recieved a problem from Bernoulli that he solved and published the solution to anonymously. Bernoulli was easily able to identify Newton as the author "as the lion is known by its paw"--that is, by the style and depth of insight in the solution.
It gets worse. Your model plane (say a quarter-scale model) is a potential cruise missile.
About ten years ago I invented a fast, robust image registration algorithm ("psuedo-correlation") that let me do near-real-time alignment of low-quality images on a 100 MHz 486. I was working in medical physics at the time, and my goal was to allow near-real-time (a few seconds) evaluation of patient setup in radiotherapy using online portal imaging (portal imaging is taking x-rays of people during radiotherapy using the therpeutic beam, so you can tell which bits you're hitting.)
After publishing, I realized I'd invented a terminal-phase guidance system for cruise missiles that would run on commodity hardware. Over the past ten years things have only gotten worse: I expect that a not-insignificant fraction of/. readers would be able to build such a device for ~$10K U.S. All you need is a quarter-scale model, a GPS, a camera and a laptop. It wouldn't be elegant, but it'd do the job.
I'm comfortable posting this because it isn't news: similar ideas have been covered in the mainstream media over the past year.
The genie is well and truly out of the bottle, and our only true security will be found in building a society where the vast majority genuinely support the status quo, so they have no incentive to use the destructive power that everyday technology places in their hands.
Slashdot Mirror
Several other people have pointed out that hydrogen has value as a means of transmission of power that makes it a useful step in the transition toward complete reliance upon indefinitely sustainable energy sources. Hydrogen/solar and hydrogen/wind are natural combinations, as both sun and wind are abundant resources that often aren't co-located with high densities of energy consumers.
But it gets better.
Hydrogen as a transport medium has three big advantages over electricity: transmission is relatively lossless, hydrogen can be stored far more easily than electricity, and hydrogen is better suited to powering small mobile engines, such as those found in automobiles. On the first point, roughly 40% of electricity generated in Canada (admittedly a worst case) goes into line losses. The number in the U.S. isn't that much lower. Ergo, hydrogen production can be moderately inefficient compared to simple electricity generation and still break even on efficiency grounds.
Most importantly, however, cars that use hydrogen generated from burning coal, oil or gas would be far more energy-efficient and less poluting of the atmosphere than gasoline powered automobiles. The reason for this is simply that large stationary power-plants are much easier to load with all kinds of fancy efficiency-enhancing, polution-reducing technology than cars are. Small, mobile power plants suffer from all kinds of practical engineering constraints (weight, size, cycle-of-use,...) that don't affect big stationary power plants.
--Tom
I read this book a while back, and was really impressed by it. It is probably the best book on "the golden age of piracy" I've encountered--much better than Johnson's.. err.. Defoe's.. err.. whoever's.."General History" and vastly more readable than the (admitedly more scholarly) "Under the Black Flag" by David Cordingly.
"Pirate Hunter" is much more than a biography of Kidd--it is a vivid re-creation of the life and society of European pirates at the turn of the 18th century.
It also contains food for thought for techies who think that if they do a good job they'll be rewarded for it. The contrast beween Kidd, who believed himself innocent, trusted the system, and was hanged; and Robert Culliford, who believed himself guilty, worked the system, and walked free, is an object lesson to all virtuous people.
If Kidd had understood the veniality of the majority of nominally decent people whom he dealt with he might still be alive today.
--Tom
Isn't it interesting that when women die or have poor health it's viewed as a societal problem and when men die or have poor health it's viewed as our own damned fault?
Men die because our lives are less valued than women's, and we are brought up to value our lives less. We are surrounded by cultural propoganda dedicated to the proposition that the gruesome death of a young man is, literally, glorious.
Until we value the lives of men as highly as we value the lives of women, men's lives will continue to be shorter and poorer than women's.
The data reported in this study contain many subtle cues as to how men routinely mistreat themselves: for example, men take fewer disability days than women. This is not because men suffer from fewer hurts and harms, but because we are taught from birth that it's more important to sacrifice ourselves than take to care of ourselves. And sacrifice ourselves we do.
--Tom
As near as I can figure, this has nothing to do with websites and everything to do with website names. Websites are collections of information, much like books.
The articles says that the U.S. government has put website names on the list of aliases for terrorist organizations, but this does not mean the websites are in any sense terrorist organizations, any more than a book can be a terrorist organization.
For example, it would make no sense at all for the government to say: "We have placed the following books on our list of terrorist organizations: MEIN KAMPF, THE COMMUNIST MANIFESTO, THE PROTOCOLS OF THE ELDERS OF ZION, THE OXFORD ENGLISH DICTIONARY and THE FARMER's ALMANAC."
I use the OED and THE FARMER'S ALMANAC as examples because they are books that are also ongoing projects by identifiable organizations. But the books are not the organizations--they are merely a name under which the organization may be identified.
This is an important distinction because of course only someone inexcusably ignorant of history would want the goverment censoring websites. Noting that website (or book) names may be used as aliases for terrorist organizations, however, is quite a different kettle of herring.
--Tom
Good teaching at Cambridge in Newton's day was a even rarer than today. Most professors treated their positions as sinecures, and many didn't do any teaching at all. Westfall's definitive biography of Newton, NEVER AT REST, treats this in detail. So Newton was not atypical in this regard.
With regard to publication and scientific journals, the Royal Society, whose Proceedings can be considered the prototype for the modern scientific journal, was founded in 1640 or thereabouts, and there were similar foreign publications, so scientific journals did exist.
Newton published very little prior to the Prncipia because he got irritated by negative response to his work, and felt he wasted far too much time arguing with people about it.
For example one paper he published described some optical work in which he mentioned that the spectrum from a prism was linear, which ran counter to the prevailing belief that it was circular (empiricism was still very much in its infancy). He was attacked for this claim, even by people who took the trouble to look at such spectra themselves but who saw circles because that is what they expected to see.
Finally, Newton did not publish Principia primarily to further his fights with Leibniz and Hooke, which occupied him much more after the publication of the Principia than before. He published it, famously, at the behest of his friend Edmund Halley, who felt that the results were too important to go unpublished. Self-agrandizement also surely played a role, but it is extremely doubtful it was the primary cause.
Newton was a complex character, subject to fits of melancholy and maddness. In later life he was frequently described as charming--wealth, fame and power probably improved his disposition more than a little.
Given his natural abilities, he would almost certainly find himself a faculty position today at the school of his choice, as modern universities are at least as welcoming to poor but capable students as they were in Newton's day, and being socially disfunctional has rarely been a bar to academic appointment.
--Tom
Yes. I had the same thought. I'm sure others have as well. I kind of took it for granted that the SCO moves are a part of a broad-scale intentional attack on Open Source and Free Software, encouraged and funded at least in part by You Know Who.
I doubt there is a very high degree of deliberate co-ordination between parties--it's just matter of spontaneous organization, rather like the 'Net itself.
Microsoft et al must know they are doomed to become a software services company in time. Economics 101 tells us that the equilibrium market value of a good whose incremental cost of production is zero, is zero. This is exactly the situation with a mature software product. A software release that fulfills customer needs has a (nearly) zero incremental cost of production: the cost of producing the next unit is the cost of downloading.
Only when feature sets are still in flux is there any money to be made in software. As feature sets stablize (think office suites) free alternatives will catch up in functionality to commercial offerings (think OpenOffice.org). This is a cumulative process that will eventually bury most commerical software houses, whose best bet will be to become service organizations. This transition is already well underway at places like IBM.
Short-term IP protection, particularly patents, can preserve some value for commerical software, and I expect we'll see lots more attempts to exploit this path to continued economic viability simply because the profit margins on software products are stupendous compared to those on software services, particularly when you own a monopoly in a niche.
So long as the Open Source and Free Software communities exist, commercial software will be under threat. It follows from this that the major interest of commercial software vendors at this time is to gain legal protection from the OS/FS community. Once upon a time commerical software could plausibly (if not always accurately) claim technological superiority. Then it could claim superior support (less plausibly and much less accurately)--people still try this with the "total cost of ownership" argument, but it becomes less defensible on empirical grounds as time passes and more and more organizations opt for OS/FS because it really is cheaper and better supported.
The next frontier in the software industry is legal, not technological, and most of the major battles in the next decade will be fought in the courts, with all of us nerds sitting on the sidelines thinking, "I remember when technology was the stuff that mattered."
--Tom
The note in Nature says they're going to keep everything very cold, which addresses this problem. Cooling can be viewed as "pumping away degrees of freedom", at least in a quantum solid where a given mode becomes exponentially unavailable below its excitation energy.
If simply being in contact with something that was connected with the warm, mode-rich outside world via a cooling apparatus was a problem for an experiment like this, then it would also be a problem for superposition experiments with superfluids and superconductors. Given that cooling solves the problem in those cases, it will solve the problem in this case as well.
I believe the more important effect is that cats (complex systems) have many modes themselves, which are strongly coupled to each other, so that that any effect that depends on the long-term or long-range coherence of any given mode (i.e. any quantum effect) is obliterated. My own cat, Yogurt, is trying to help me type this, and he agrees with me.
--Tom
There are in fact many dark matter problems. This work deals with galactic dark matter only, which could be solved by normal matter. This is not the case for dark matter problems on larger scales.
On scales larger than galaxies, we can see that galaxies and groups of galaxies appear affected by stronger gravitational forces than can be accounted for by visible matter, and on very large scales it appears that there is more gravity than can be accounted for by ordinary matter, period.
There are strict limits on the amount of ordinary (baryonic) matter that come from primordial nucleo-synthesis. In the early seconds after the Big Bang, the quark-gluon plasma cooled down to form baryons (protons and neutrons, to you.) Eventually (some seconds or minutes later) the baryons cooled down to the point where their average energy was low enough that when they ran into each other they tended to stick together rather than flying apart again.
The nuclei formed in these early times were: hydrogen (single protons), deuterium (p+n), 3He (p+n+n), 4He (p+p+n+n) and tiny amounts of lithium and above. As you can imagine, the ratios of hydrogen to everything else are critically dependent on the density of neutrons at the time these nuclei were forming: the more neutrons, the more heavy nuclei. We can infer from observations on stars fromed shortly (~millions of years) after the Big Bang what these ratios were, which tells us the density of neutrons and protons at that time. We also know the volume (curvature) of the universe at that time, and so can infer the total number of baryons in the universe.
There are not enough baryons to account for the gravitational (or gravity-like) forces acting at the largest observable scales. Ergo, something else is happening (or the observations are wrong, which is always a possibility.)
Given the number of dark matter problems, it is unlikely that one particle will solve them all, and quite possible that we are seeing the effects of quite different causes at different scales. This should not be a surprise. For example, we already see very different causes at nuclear scales vs. atomic scales vs planetary scales. It is possible that on galactic and size-of-the-universe scales different causes are at work as well, either due to hitherto undiscovered forces or equally unknown particles.
--Tom
This is a good point, but I'm sure the researchers have considered it. The limiting factor will be inelastic flexion of the cantilever, which can be made small in a number of ways, not least of which is keeping the amplitude of vibration small. Given that they're talking about setting the thing vibrating using the momentum transfer from a single photon, this shouldn't be a huge problem!
But it does bring up an important common misunderstanding that the headline of the article repeats: quantum effects have absolutely nothing to do with size and everything to do with complexity. A photon that passes through both slits of a double-slit apparatus demonstrates quantum effects on a scale of a fraction of a millimeter (the separation distance of the slits) and large multi-path interferometers of one kind or another involve photons that take paths that are tens of centimeters or more apart.
Size doesn't matter. What matters is the number of modes available, because interference between modes destroys our ability to observe quantum effects. Systems of many particles (particularly at higher temperatures) have so many modes available that the coherence time is extremely small, although even then we can under the right circumstances observe things like the Mossbauer Effect in which an entire block of material acts as a single quantum-mechanical entity.
--Tom
This article is mostly dead-on, but misses the mark in two respects on the loyalty question.
In the first place, it's wrong to say that companies are loyal to their Boards of Directors, or shareholders. The fact is that companies are loyal to nothing whatsoever, except possibly to the neurotic personal needs of their executives and managers. If companies were loyal to their boards or shareholders we wouldn't see the gross mis-management and poor corporate governance that is all too common.
In the second place, employees should not just not be loyal, they should be actively disloyal, in the sense that every employee should be in the job market all the time. Seriously.
That means keeping your resume up-to-date, and reading the job ads in your field (print and on-line) regularly. If you see something that looks particularly interesting, don't be shy about applying for it, and if you get an interview go for it. It'll keep your interview skills in shape, and you never know--it might be your dream job. Don't worry about wasting anyone's time: as mentioned by other posters, companies advertise jobs they have no intention of filling, so turn-about is fair play.
Furthermore, you should be fairly up-front with your current employer about this attitude after you've been with them for a year or so. You don't have to make a big deal of it--just mention casually now and then that you've seen that Company X is hiring (it helps if Company X is a well-known competitor, as your boss won't know if you're keen and keeping an eye on the market or thinking of jumping ship.)
No matter who you work for, you are your own boss. You are the only boss who will ever care about your career, your goals, your well-being or the well-being of your family.
After moving into the tech world from academia seven years ago, I've had five jobs. I jumped ship twice, companies folded twice, and I'm currently running my own business after a period of unemployment resulting from the last company folding, so I know whereof I speak. Both as a developer and a manager I pursued the policy I've outlined above.
As a manager, I encouraged members of my team to do the same--I wanted them to be able to walk in the door in the morning and ask, "What has the company done for me lately?" and be able to find an answer that would motivate them to work hard and well, which they did. Of course, part of the answer to that question is always, "Paid my salary", which is important to keep in mind.
Senior management, of course, did not like my attitude--amongst other things, they were unhappy that I insisted that every member of the development team actually take all the accrued vacation owing to them! But so long as my team kept mysteriously producing outstanding results they had to put up with it.
And equally unsurprisingly, those outstanding results did not stop half my team from being laid off (over my objections) a few months prior to the company folding up.
--Tom
If this person was a writer/researcher/whatever for a company, and he made comments that were not only attributed to him, as an individual, but to the company he worked for- yes, they can get rid of him.
What part of "the views of the authors are theirs and theirs alone" don't you understand?
--Tom
This design may account for the fairly astonishing efficiency claims, as well: the light is getting focussed onto a small area, and the chips will be running at very high temperatures.
Despite the complex quantum-mechanical nature of photovoltaic conversion, there are still underlying thermodynamic limits, and to an extent they can be treated as heat engines running between 6000 K (the surface temperature of the sun) and 300 K (the surface temperature of the Earth), which gives theoretical (Carnot) efficiencies ~90%.
Good over-views are available on the web.
Focussing or concentrating sunlight should make it easier to reach something close to this efficiency in practice.
That said, these suckers are going to have lots of moving parts (phased arrays, anyone?) and it's likely to be a while before we are buying them at Home Despot. And as an earlier poster pointed out, turning off the lights (just putting light switches where ordinary employees can turn off the lights!) is going to save us far more energy in the short term than anything else.
Of course, a good way to encourage people to save energy would be to create a market which could price energy appropriately given the level of supply and demand, rather than running about in a panic and capping the price every time it looks like consumers might actually notice the bite their energy bills are taking out of their bank account.
--Tom
Several comments:
1) The argument that "the Japanese didn't have a great industrial infrastructure" and therefore an invasion of mainland Japan would have been relatively bloodless does not hold water. To name just a couple of nations that had even less industrial infrastructure than Japan circa 1945: Afgahnistan in the '80's and Vietnam in the '70's. Ill-equiped local forces fighting "the little war" have for centuries proven to be formidable enemies to technologically superior foreign invaders.
2) Total victory was a political, not a military requirement, and it was justified by reference to the unsatisfactory outcome of "technical victory" in WWI. It was a widely and plausibly held view that anything short of total victory would result in another world war in 25 years, just like the last time.
It is always easy to solve problems we never had--the invasion of mainland Japan, or the creation of a lasting peace after a "technical victory" over an unconquered enemy. But we know with certainty from similar cases that those scenarios would play out with at least as much bloodshed and horror as we actually had.
--Tom
Not if you're making helium from deuterium, there aren't - you get them in hot fusion where tritium is being used (there are spare neutrons to go round), but 2 deuterium nuclei will make 1 helium-4 nucleus + energy.
And the 4-He will in fact get most of that energy, which will make it move so fast that it will knock neutrons off deuterium nuclei (and other nuclei) while slowing down. If the 4He doesn't get the energy, it must come out in gamma rays (ignoring inadequate coupling constants for a moment--we're doing phictional physics here).
Neither neutrons nor gamma rays are observed. Nor, for that matter, is 4He.
Ergo, no nuclear processes are occuring
--Tom
It was a 17 keV neutrino, and neither it nor the fifth force deserve to be in this list. Both were valid (if somewhat over-enthusiastic) interpretations of experiments that were carried out with good technique.
The 17 keV neutrino in particular showed up in both Simpson's tritium spectra and in 14-C measurements made a Berkeley. It was that latter measurements that made most of us take notice.
The first experiments that failed to see the 17 keV neutrino were not as rigorous as one would like, and Simpson was in my view justified in his criticisms. 2nd generation experiments, such as my own measurement on 35-S, were done more carefully in consequence, and the scientific community had relatively little trouble coming to concensus that there ain't no 17 keV. Even Simpson and Hime agree with this, and no one thinks that they were anything but unlucky.
Cold fusion is not like this. Those who claim positive results can't come up with a consistent universe of phenomena that requires explaining, and they continually promise definitive results "real soon now" and have been for a decade or more.
This is not science, but nonsense.
--Tom
"Dressing up" became the norm (that is, for normal people, as opposed to the extremely rich or aristocratic people) about two hundred years ago, when industrial technology made cheap clothing available to the normal people.
--Tom
Acts 19:19-20:
Many of them also which used curious arts brought their books together, and burned them before all [men]: and they counted the price of them, and found [it] fifty thousand [pieces] of silver.
One can argue about the specific direction a Christian should take from this (should you burn only your own books or other people's too?) but there is no doubt that book burning has been seen as something of value to Christians from very nearly the beginning. The books described in Acts were probably arcana of various kinds, primarily judicial astrology and the like. To a Christian many of the books in the Royal Library would have fallen into the same category.
I don't believe that Christians were responsible for burning the Royal Library at Alexandria. But they have certainly been responsible for burning many other books--in Alexandria and elsewhere--over the past 2000 years. They have no monopoly on this behavior, though: book-burning is one of the pass-times that all tyrants, religious or secular, engage in.
To pose the question of the burning of large collections of books in Alexandria as an either-or is to forget that, given how long Alexandria has been a center of learning, there have been more than enough books there for everyone to have their fair share of burnings, hatred and destruction.
--Tom
Pompeii and Herculaneum were something akin to the Las Vegas of Rome.
Pornography is a basic metric of human economic well-being. In any society with sufficient wealth porn and prostitution are rapidly industrialized, often preying on the least advantaged members of society to the benefit of the most advantaged.
This was as true in Rome 2000 years ago as it is in America (or Tailand) today.
--Tom
However, there are better ways of making 3-He (a major source today is tritium decay, tritium being bi-product of heavy water reactors.) And the very fact that a small amount of 3-He can make a large amount of energy means that you don't need to produce huge amounts of 3-He to run fusion reactors on it.
Ergo, it is unlikely to be a major factor in space exploration. Unfortunately the simple extraction of raw materials is not likely to ever be sufficient to justify space exploration on a commercial basis. Natural resources are not likely to ever again be a major economic driver: intelligent use of resources, including recyling, is almost always a better investment.
On the other hand, the more efficiently we use resources (which incidently means the less polution we create) the wealthier we will be, and therefore the more exotic vacation location we'll be able to visit...
--Tom
Aspect-oriented programming has been talked about for a while now, but it still isn't nearly ready for prime time. The obvious issues are that it will introduce bugs and that it will be at the same time very hard to debug.
The first goes without saying: every new technique can be considered a collection of novel ways that things can go wrong. Insofar as AOP is powerful, it will create whole new classes of bugs.
Things like AspectJ make things worse, though, because they are pre-processors. So debugging is going to involve tracing into machine-generated code. This does not need to be a nightmare, but somehow it almost always is.
There is also the issue of debugging your aspect specifications themselves, alluded to briefly in the article with the point about infinite recursion. I'm sure there are many other subtle and interesting bugs that AOP can introduce, and I'm very grateful to all the eager souls who are going to find and fix them over the next few years.
I think AOP solves a legitimate problem. I'm not by any means sure it's the best solution. In a few more years, when tools and techinques have matured a little, it may prove to be a valuable technique.
--Tom
Suicide amongst young people is dominated by suicide amongst boys.
--Tom
This is actually one of the impediments to commercial fusion power: reactors efficient enough to generate commerical power will have to be big, which is a problem because "big" translates to "takes a long time to build" and no one knows what the demand for power will be two years from now, much less ten or fifteen.
Getting capital together for such a project won't be easy, and there are only a few locations where a 20 GW plant makes any kind of sense.
So the economic problems faced by the fusion power industry will be a large multiple of those faced by the fission power industry.
--Tom
--Tom
See for example Newton Timeline. Note the item for 1697, when Newton was 55. He recieved a problem from Bernoulli that he solved and published the solution to anonymously. Bernoulli was easily able to identify Newton as the author "as the lion is known by its paw"--that is, by the style and depth of insight in the solution.
--Tom
It gets worse. Your model plane (say a quarter-scale model) is a potential cruise missile.
About ten years ago I invented a fast, robust image registration algorithm ("psuedo-correlation") that let me do near-real-time alignment of low-quality images on a 100 MHz 486. I was working in medical physics at the time, and my goal was to allow near-real-time (a few seconds) evaluation of patient setup in radiotherapy using online portal imaging (portal imaging is taking x-rays of people during radiotherapy using the therpeutic beam, so you can tell which bits you're hitting.)
After publishing, I realized I'd invented a terminal-phase guidance system for cruise missiles that would run on commodity hardware. Over the past ten years things have only gotten worse: I expect that a not-insignificant fraction of /. readers would be able to build such a device for ~$10K U.S. All you need is a quarter-scale model, a GPS, a camera and a laptop. It wouldn't be elegant, but it'd do the job.
I'm comfortable posting this because it isn't news: similar ideas have been covered in the mainstream media over the past year.
The genie is well and truly out of the bottle, and our only true security will be found in building a society where the vast majority genuinely support the status quo, so they have no incentive to use the destructive power that everyday technology places in their hands.
--Tom