"Typical wavelengths of the laser beams are 850 nanometers and 1,550 nanometers, neither of which is dangerous if used properly, said Jeff Hecht, author of "Understanding Fiber Optics" (Prentice Hall). Wavelengths of 850 nanometers can pass through the cornea of the eye and reach the retina, damaging receptors, so these lasers are usually operated at lower power. Higher power is possible with 1,550-nanometer lasers, Mr. Hecht said, so these are used for longer distances."
I work with near-infrared lasers on a regular basis (I do biomedical optics research) and I can
tell you that despite the text of the article, 1550nm is quite cabable of cooking an eyeball.
The reason they use 1550nm for telecomm is that
it sits in the center of an absorbtion minimum (one of the water window) which minimizes losses, but that also increases its penetration through your eyeball. I really wonder if these things comply with ANSI Z136 (laser safety standard, here in MA required by state law; I don't know about NY). From the text of the article, I have my doubts.
Near-IR lasers, even at quite low output powers, are extremely dangerous eye hazards simply because the beam is invisible. You don't know you're getting an eye-full until your vision starts to fade (permanently!).
Look at the makefile for emacs--the emacs executable is essentially a memory dump of a partially initialized emacs process. Perl's dump and undump work the same way.
For long-running processes, rather than shut down the process when the UPS kicks in, I've always found it easier to have the program snapshot its data tables periodically (say every half-hour) and build a "resume from disk" feature into the program. This lets you restart the program from its last check-point even in the event of uncontrolled program termination (e.g. kill -9 and the like).
ER, I was under the impression that one's security clearance, or lack thereof (or perhaps just the level of clearance) were classified.
Was I mistaken?
Yes. You are prefectly free to discuss your clearance, just not the information (or sometimes even the types of information) taht the clearance gives you access too.
I do programming for physics problems in a variety of languages and I've found OO programming techniques work best when the "data" can be represented as objects. This makes OO approaches very natural in GUI's, where all the different widgets share certain common traits (position, isvisible(), drawing, etc) and some traits that are unique to the object (is the button pressed, etc). It also comes in handy for both multi-threaded applications and talking to hardware where the thread/hardware can be encapsulated in an object and the object will handle the details of allocation, deallocation, etc.
For most physics/engineering problems, though, you only have a single type of object. For example, in a FEM heat transfer problem you would have
A vector that relates actual position (x,y,z) to node index
The thermal conductivity at each node (a REAL)
The current temperature at each node (a REAL)
There is no hierarchy of data here to exploit, so proceduraly progamming will be the easiest to work with (especially if that means using a language you're already familiar with).
Let the data determine the language you use, not the other way around.
2. Most meaningful research comes from the private sector (bell labs and the like) with a few exceptions (Darpa)
Most meaningful reasearch, by any standard you care to name (dollars spent, papers written, patents granted, etc), comes from Universities. In the US, almost all industrial basic research (IBM being a notable exception) has been eliminated in the names of quarterly profits. The problem is that the return on basic research doesn't arrive for 5-10 years and most companies don't look beyond next quarters balance sheet.
And, since you brought it up, Bell Labs no longer exists. When AT&T split itself up, the old Bell Labs became Lucent Corporation. The research parts of Lucent pretty much ceased to exist as of the recent restructuring where research was split up between Lucent, Agere, and Avaya.
And, as someone else pointed out, DARPA is only for the U.S. military and is a primarily funding agency, not a research lab. U.S. civilian research is funded largely by DOE, NSF, and NIH.
Since the newpaper writer clearly hasn't a clue what he's talking about, I ran over to the TRIUMF webpage for the actual story. Here's what they
have to say in the "News" section:
TRIUMF SUCCESSFULLY ACCELERATES RADIOACTIVE EXOTIC ION BEAMS
Research with radioactive exotic ions is recognized worldwide as an exciting new frontier in physical science. ISAC, one of the world's first facilities specifically dedicated to the production and acceleration of such exotic ions, has been developed and constructed at TRIUMF, Canada's national laboratory for particle and nuclear physics. Low energy exotic beams were first produced in 1999 and during the past summer the exotic ion 8Li was the first beam to be successfully accelerated to high energy (~1.5 MeV/A). On the 5th of October an accelerated beam of 21Na (a radioactive isotope of sodium) was produced (at a preliminary intensity of about 4x108 particles per second on target) and experiments with this beam are producing the first data concerning nuclear processing of sodium in stellar explosions.
For the future, there are plans to accelerate a whole variety of exotic isotopes that will be used to address a wide range of research areas.
So, to sum up, they've got their isotope accellerator up and working to the point where they can do some very nice experiments on high-energy nuclear processes, including a number that are important in stellar explosions.
No supernova though.
It doesn't mean that Verizon is right in wanting to squash all competition, but there are things called natural monopolies.
Your electric company is one. Water services.
These are (or were until a few years ago) called
regulated monopolies, not natural
monopolies. They were premitted monopoly control (generally by the individual state governments) in exchange for accepting an unusually high level of state oversight, including but not limited to limits on rates and corporate profits.
Verizon (formerly Bell Atlantic, which owned half the other baby bells) was also a regulated monopoly until the telecom reform act of a few years back.
The fate of the universe is held by dark matter. Without dark matter, there is insufficient gravity to bind all matter together forever. If there is enough dark matter, with its attendant gravity, then eventually the universe will collapse back onto itself. Probably the end result of that would be another Big Bang.
There almost certainly is not enough matter
for the universe to collapse back in on itself.
Extrapolating from the motions of galactic clusters, you compute a mass of the universe anywhere from 30--70% of the critical mass for the universe to fall back in on itself. Of this 30-70%, only a fraction is visible with telescopes. The rest is "dark" (hence the name). Also,
the larger the structures you look at, the higher the mass fraction you extrapolate (the 70% figure comes for the motion of galactic super-clusters), which again supports the notion that the mass is out there between the galaxies but for whatever reason it isn't visible to our telescopes.
Where it gets interesting is that a certain class of cosomological models (inflationary models) seem to work extremely well, but want the mass of the universe to be exactly at the critical mass (as an aside, this also means the curvature of space is infinite, i.e. the universe has a Euclidean geometry). The real dark matter question isn't so much where is the ordinary mass that we know has to be there but can't directly image (although that's an interesting question in its own right). The real question is where is the mass necessary to make up that last 30% or so to get us up to the critical mass. WIMPs are one possibility, a non-zero cosmological constant is another.
I find it very amazing that some people think the speed of light and other 'constants' could not have changed in the distant past from a value much different than what we observe today.
If they were different, it would have testable consequences (the angular distribution of fluctuations in the cosmic microwave background would be different, the amount of deuterium in interstellar space would be different, etc.)
To date, all evidence says the speed of light and the other fundamental constants truely are constants.
As a solid-state physicist (I did my dissertation in the field of soft condensed matter physics),
I just have to say My God, that article is one of the biggest flying loads of journalistic crap I've ever seen!
"At issue is a deep epistemological matter having to do with what physics is."
Never trust an physics article with the words "synergy", "epistemological", or "paradigm" in either the title or the abstract. They're universally crap. If they weren't crap, the author wouldn't need to obfuscate the reader by using flowery information-free phrases.
Many complex systems - the very ones the solid-staters study - appear to be irreducible. Made of many interlocking parts, they display a kind of synergy, obeying "higher organizing principles" that cannot be further simplified no matter how hard you try.
What the hell is that supposed to mean? "Higher organizing priciples"? What is this guy, some
sort of directed-evolution creationism disguised
as objective journalism? Sure there are things in physics no one has clearly explained yet, but
"cannot be further simplified" has, historically, almost always proven to be wrong.
Carrying the idea even further, some solid-state physicists are trying to show that the laws of relativity, long considered part of the very bedrock of the physical world, are not platonic truths that have existed since time began.
First, no physicist has every seriously claimed that any theory of physics is a Platonic truth (although I've seen the occational philosopher try). Second, solid state physics types don't try to study relativity for two reasons: first, we don't have the background to do so credibly and second, general relativity is not observable in the laboratory and thus is not a subject most solid state physicists are interested in.
They may have emerged from the roiling of the vacuum of space, much as supply-and-demand and other "laws" of economics emerge from the bustle of the marketplace. If so, then solid-state physics, which specializes in how emergent phenomena occur, may be the most fundamental science of them all.
Solid state physicists (or condensed matter physicists, same idea) do not specialize in "how emergent pheomena occur" (whatever the hell that means). We study matter in the solid state (superconductors or semiconductor physics for example). Touchy-feely stuff, things you can put on a lab bench.
This approach, in which the most complex phenomena are boiled down to a unique underlying theory, is called reductionism.
Only by English majors. Physicists call it "trying to understand what's actually going on".
The problem, the solid-staters say, is that many forms of matter - ranging from the exotic like superconductors and superfluids to the mundane like crystals and metals - cannot be described in terms of fundamental particle interactions.
The hell they can't. Just because I can't sit down with a pen and paper (or a Cray supercomputer) and solve the resulting system of equations doesn't mean they don't apply.
These so-called "new laws" are just approximations to the real (albeit unwieldy) quantum mechanics.
In the world of solid-state physics, quasi particles abound. In some substances, like the semiconductors used to make computer chips, the displacement of an electron leaves behind a "hole" that behaves like a positively charged particle.
The difference is, quasi-particles are not real. They're a useful mathematical trick, but without an underlying object (usually a crystal of some kind), they wouldn't exist. Electronts are real.
Quarks, the basic building blocks of matter, also carry a one-third charge,
They found bodies at Herculaeneum, which is one of the few finds of Roman remains because Romans followed the funerial practices of their nomadic forebears -- cremation. At least, the patricians did so.
The found bodies (well, skeletons) at Herculaeneum, not because of any nonsense about funeral practices but because the bodies were encased in solid rock during the eruption. Pyroplastic flows and all that.
It's a fairly standard CCD resolution. CCD chips that size are cheap, reliable, and redily available as off the shelf components.
You can't go too wrong with 'em.
Exceptions are mandatory for good programming, period. If the language you are using doesn't support exceptions (C, Perl, etc), you are going to have problems.
That's Bull. I've used lots of exceptionally well
written code from the 1960's and 1970's, a good 20
years before C++ (and C++-style exceptions) hit a
critical mass. The code is in Fortran (F66 no
less), a language which utterly lacks exceptions.
I've personally written Perl and C code that gracefully handles any possible error. If an error occurs and you aren't aware of it, then you're not doing your job as a programmer.
The most important prerequisit for having good robust code is to always check the return value of your library calls. malloc() returns NULL on error, time() returns -1 on error, etc. Yes, it's still possible to write buggy code, but it's impossible to write do so without assiduosly checking checking return values.
-JS
P.S. assert() can be a big help too.
Not as graceful, I'll grant you, but an excellent
tool to insure that those little "this isn't possible" results really are impossible.
I think the Watergate/Iran-Contra/etc. hearings provided ample evidence that the spook community is quite happy to ignore the law, executive orders, the Constitution, and certainly their charters if and when they (not congress or the
president, mind you, but the spooks themselves) decide it's in the interests of "national security" to do so.
Particles that can all have the same EXACT state, in quantum mechanical terms, are called. They fill and occupy available states in a certain way, described by a Bose distribution.
Um, no. Bosons are (by definition) particles with integer spin (0, +1, -1, etc.).
An example of bosons are photons, or light, which can all be in the same state at the same time, hence making the maser and laser possible.
Umm, no. Photons, because the have no mass, are completely unable to form a Bose-Einstein condensate. In a laser, the photons are emitted with coherent phase. This is not at all the same as being in the same quantum-mechanical state.
IANAP (I Am Not A Physicist), so I can't comment on why a Bose-Einstein Condensate is a benefit to mankind. I'm sure some kind slashdotter can help here.
IAAP and, aside from experimentally confirming a very large
chunk of theoretical physics, forming
the basis for atomic "lasers" (coherent beams of atoms), and showing the path for building new still more mind-numbingly accurate atomic clocks, BEC's are also one of the more promising candidates for the eventual construction of a practical quantum computer. Give it 20 years; we've only seen the tip of the iceburg on this one.
The internet/www is one of those really nifty technologies that changes the whole way of doing many things. Because the internet allows for incredible amounts of interactivity (not taken advantage of by most sites), peer review suddenly becomes much more "real". Traditional journals have a small number of peers who serve to review any given article, and constant discussion is not generally published.
The internet of course can completely change that where any peer can review any work. And why stop at scientific publishing? And why stop at publishing for that matter. Much published work serves an educational purpose as well as a documentary purpose.
As someone who publishes in traditional peer-reviewed journals, let me add a few comments to this. What journal peer review provides that can never be replaced by an open forum like Slashdot is credibility. The journal editor is responsible for selecting reviewers who are knowledgeable in their field. These editors,
at least in the physics journals I've worked with, are responsible professionals committed to publishing a high-quality journal and not just
ego-driven hacks. Because the editors are considered trust-worther by the journal readers, articles subjected to a peer-review process can be take seriously (they can still have mistakes,
of course, but usually not obvious ones).
Similarly, because article reviewers are selected
based on their professional credentials, reviewer comments in a peer-reviewed journal are worth my serious consideration. I may disagree, with the reviewer, but that's part of the process and I'm given the opportunity to respond to the reviewer's criticisms as a normal part of the review process. Finally, because the review is blind (either single-blind or double-blind depending on the journal), the reviewer can safely criticize a more established colleague without fear of retribution. On a peer-reviewd journal, with an
editor as the final arbitrator, this procedure works. On the internet, though, either reviews are public which opens the viewer up to retribution, or the reviews are completely anonymous in which case the reviewer lacks all credibility.
A comment made by a random AC on slashdot, in contrast, is not worth my [professional] time.
There are just too many posts by too few knowledgable people. Even with the established pre-print servers (which are not peer reviewed but of considerably higher signal-to-noise ratio than most other public forums), it isn't worth the time and effort to read the articles unless I already know one of the authors, either personally or by reputation.
In sort, peer-review is not some arbitrarily imposed requirement from on high; when handled properly it is a valued part of the scientific process and
I will not take the time to read any journal
that does not maintain peer review.
There are only so many hours in a day and I would prefer to use them to get real work done instead of wading through a stack of dubious articles on the off chance that one of the authors will have something worth-while to say.
-JS
P.S. For the record, I read slashdot on my
own [personal] time. This is entertainment,
not work.
Not so in Israel. All Muslim citizens have the right to vote and to worship however they choose.
Most muslims in Israel are not Israeli citizens.
They cannot buy land (regardless of the law). The
borders to the occupied territories can be closed
any time the government feels like, making it impossible to hold a job. It's no wonder Hamas
has an easy
time recruiting suicide bombers when they have such a large pool of young men with literally nothing worth living for. This doesn't, of course, make it right, but Israel (and especially the Sharon government) is in a stew of its own making.
It's only fools who think that Israel is the problem.
It's only zealots who won't recognize that Israel
and the US are equally part of the problem.
-JS
Re:there's an argument to be made....
on
More On Tragedy
·
· Score: 1
User #410832 Info) "the number one export
for the United States is weapons."
Oh? And where do you get your numbers? Either way,
I find it hard to believe in light of how the
number one exporter of weapons globally is France.
The U.S. passed France for the honor of "world's largest arms exporter" right after the Gulf
war.
Polonium has a half-life of only 138 days. So, even though the plutonium itself decays very slowly, it is the initators that must be regularly replaced.
It depends on the isotope. Po-209, for example, has a half-life of 105 years. I don't have my nuclear physics references on hand, but the decay energies look sufficient to knock of the outer neutron of Beryllium and start the reaction.
Boosted fission bomb designs that use tritium (12 year half-life) instead of deuterium, on the other hand, are probably a real pain to maintain.
Slashdot Mirror
I work with near-infrared lasers on a regular basis (I do biomedical optics research) and I can tell you that despite the text of the article, 1550nm is quite cabable of cooking an eyeball. The reason they use 1550nm for telecomm is that it sits in the center of an absorbtion minimum (one of the water window) which minimizes losses, but that also increases its penetration through your eyeball. I really wonder if these things comply with ANSI Z136 (laser safety standard, here in MA required by state law; I don't know about NY). From the text of the article, I have my doubts.
Near-IR lasers, even at quite low output powers, are extremely dangerous eye hazards simply because the beam is invisible. You don't know you're getting an eye-full until your vision starts to fade (permanently!).
-JS
For long-running processes, rather than shut down the process when the UPS kicks in, I've always found it easier to have the program snapshot its data tables periodically (say every half-hour) and build a "resume from disk" feature into the program. This lets you restart the program from its last check-point even in the event of uncontrolled program termination (e.g. kill -9 and the like).
-JS
Yes. You are prefectly free to discuss your clearance, just not the information (or sometimes even the types of information) taht the clearance gives you access too.
-JS
For most physics/engineering problems, though, you only have a single type of object. For example, in a FEM heat transfer problem you would have
- A vector that relates actual position (x,y,z) to node index
- The thermal conductivity at each node (a REAL)
- The current temperature at each node (a REAL)
There is no hierarchy of data here to exploit, so proceduraly progamming will be the easiest to work with (especially if that means using a language you're already familiar with).Let the data determine the language you use, not the other way around.
-JS
Most meaningful reasearch, by any standard you care to name (dollars spent, papers written, patents granted, etc), comes from Universities. In the US, almost all industrial basic research (IBM being a notable exception) has been eliminated in the names of quarterly profits. The problem is that the return on basic research doesn't arrive for 5-10 years and most companies don't look beyond next quarters balance sheet.
And, since you brought it up, Bell Labs no longer exists. When AT&T split itself up, the old Bell Labs became Lucent Corporation. The research parts of Lucent pretty much ceased to exist as of the recent restructuring where research was split up between Lucent, Agere, and Avaya.
And, as someone else pointed out, DARPA is only for the U.S. military and is a primarily funding agency, not a research lab. U.S. civilian research is funded largely by DOE, NSF, and NIH.
-JS
So, to sum up, they've got their isotope accellerator up and working to the point where they can do some very nice experiments on high-energy nuclear processes, including a number that are important in stellar explosions. No supernova though.
-JS
These are (or were until a few years ago) called regulated monopolies, not natural monopolies. They were premitted monopoly control (generally by the individual state governments) in exchange for accepting an unusually high level of state oversight, including but not limited to limits on rates and corporate profits.
Verizon (formerly Bell Atlantic, which owned half the other baby bells) was also a regulated monopoly until the telecom reform act of a few years back.
-JS
There almost certainly is not enough matter for the universe to collapse back in on itself. Extrapolating from the motions of galactic clusters, you compute a mass of the universe anywhere from 30--70% of the critical mass for the universe to fall back in on itself. Of this 30-70%, only a fraction is visible with telescopes. The rest is "dark" (hence the name). Also, the larger the structures you look at, the higher the mass fraction you extrapolate (the 70% figure comes for the motion of galactic super-clusters), which again supports the notion that the mass is out there between the galaxies but for whatever reason it isn't visible to our telescopes.
Where it gets interesting is that a certain class of cosomological models (inflationary models) seem to work extremely well, but want the mass of the universe to be exactly at the critical mass (as an aside, this also means the curvature of space is infinite, i.e. the universe has a Euclidean geometry). The real dark matter question isn't so much where is the ordinary mass that we know has to be there but can't directly image (although that's an interesting question in its own right). The real question is where is the mass necessary to make up that last 30% or so to get us up to the critical mass. WIMPs are one possibility, a non-zero cosmological constant is another.
-JS
If they were different, it would have testable consequences (the angular distribution of fluctuations in the cosmic microwave background would be different, the amount of deuterium in interstellar space would be different, etc.)
To date, all evidence says the speed of light and the other fundamental constants truely are constants.
-JS
Never trust an physics article with the words "synergy", "epistemological", or "paradigm" in either the title or the abstract. They're universally crap. If they weren't crap, the author wouldn't need to obfuscate the reader by using flowery information-free phrases.
What the hell is that supposed to mean? "Higher organizing priciples"? What is this guy, some sort of directed-evolution creationism disguised as objective journalism? Sure there are things in physics no one has clearly explained yet, but "cannot be further simplified" has, historically, almost always proven to be wrong.
First, no physicist has every seriously claimed that any theory of physics is a Platonic truth (although I've seen the occational philosopher try). Second, solid state physics types don't try to study relativity for two reasons: first, we don't have the background to do so credibly and second, general relativity is not observable in the laboratory and thus is not a subject most solid state physicists are interested in.
Solid state physicists (or condensed matter physicists, same idea) do not specialize in "how emergent pheomena occur" (whatever the hell that means). We study matter in the solid state (superconductors or semiconductor physics for example). Touchy-feely stuff, things you can put on a lab bench.
Only by English majors. Physicists call it "trying to understand what's actually going on".
The hell they can't. Just because I can't sit down with a pen and paper (or a Cray supercomputer) and solve the resulting system of equations doesn't mean they don't apply. These so-called "new laws" are just approximations to the real (albeit unwieldy) quantum mechanics.
The difference is, quasi-particles are not real. They're a useful mathematical trick, but without an underlying object (usually a crystal of some kind), they wouldn't exist. Electronts are real.
Except when they carry an -2/3 charge.
Yours in disgust,
-JS
The found bodies (well, skeletons) at Herculaeneum, not because of any nonsense about funeral practices but because the bodies were encased in solid rock during the eruption. Pyroplastic flows and all that.
-JS
It's a fairly standard CCD resolution. CCD chips that size are cheap, reliable, and redily available as off the shelf components. You can't go too wrong with 'em.
-JS
That's Bull. I've used lots of exceptionally well written code from the 1960's and 1970's, a good 20 years before C++ (and C++-style exceptions) hit a critical mass. The code is in Fortran (F66 no less), a language which utterly lacks exceptions. I've personally written Perl and C code that gracefully handles any possible error. If an error occurs and you aren't aware of it, then you're not doing your job as a programmer.
The most important prerequisit for having good robust code is to always check the return value of your library calls. malloc() returns NULL on error, time() returns -1 on error, etc. Yes, it's still possible to write buggy code, but it's impossible to write do so without assiduosly checking checking return values.
-JS
P.S. assert() can be a big help too. Not as graceful, I'll grant you, but an excellent tool to insure that those little "this isn't possible" results really are impossible.
No such luck, I just got blocked while using Mozilla 0.9.1 for Linux.
-JS
And they would admit it if they did?
I think the Watergate/Iran-Contra/etc. hearings provided ample evidence that the spook community is quite happy to ignore the law, executive orders, the Constitution, and certainly their charters if and when they (not congress or the president, mind you, but the spooks themselves) decide it's in the interests of "national security" to do so.
-JS
It is not possible to reach absolute zero (that's one of the laws of thermodynamics). These experiments were done at around 20 nanokelvin.
-JS
Um, no. Bosons are (by definition) particles with integer spin (0, +1, -1, etc.).
Umm, no. Photons, because the have no mass, are completely unable to form a Bose-Einstein condensate. In a laser, the photons are emitted with coherent phase. This is not at all the same as being in the same quantum-mechanical state.
-JS
IAAP and, aside from experimentally confirming a very large chunk of theoretical physics, forming the basis for atomic "lasers" (coherent beams of atoms), and showing the path for building new still more mind-numbingly accurate atomic clocks, BEC's are also one of the more promising candidates for the eventual construction of a practical quantum computer. Give it 20 years; we've only seen the tip of the iceburg on this one.
-JS
As someone who publishes in traditional peer-reviewed journals, let me add a few comments to this. What journal peer review provides that can never be replaced by an open forum like Slashdot is credibility. The journal editor is responsible for selecting reviewers who are knowledgeable in their field. These editors, at least in the physics journals I've worked with, are responsible professionals committed to publishing a high-quality journal and not just ego-driven hacks. Because the editors are considered trust-worther by the journal readers, articles subjected to a peer-review process can be take seriously (they can still have mistakes, of course, but usually not obvious ones).
Similarly, because article reviewers are selected based on their professional credentials, reviewer comments in a peer-reviewed journal are worth my serious consideration. I may disagree, with the reviewer, but that's part of the process and I'm given the opportunity to respond to the reviewer's criticisms as a normal part of the review process. Finally, because the review is blind (either single-blind or double-blind depending on the journal), the reviewer can safely criticize a more established colleague without fear of retribution. On a peer-reviewd journal, with an editor as the final arbitrator, this procedure works. On the internet, though, either reviews are public which opens the viewer up to retribution, or the reviews are completely anonymous in which case the reviewer lacks all credibility.
A comment made by a random AC on slashdot, in contrast, is not worth my [professional] time. There are just too many posts by too few knowledgable people. Even with the established pre-print servers (which are not peer reviewed but of considerably higher signal-to-noise ratio than most other public forums), it isn't worth the time and effort to read the articles unless I already know one of the authors, either personally or by reputation.
In sort, peer-review is not some arbitrarily imposed requirement from on high; when handled properly it is a valued part of the scientific process and I will not take the time to read any journal that does not maintain peer review. There are only so many hours in a day and I would prefer to use them to get real work done instead of wading through a stack of dubious articles on the off chance that one of the authors will have something worth-while to say.
-JS
P.S. For the record, I read slashdot on my own [personal] time. This is entertainment, not work.
As any scientist can tell you, there's no difference.
-JS
Most muslims in Israel are not Israeli citizens. They cannot buy land (regardless of the law). The borders to the occupied territories can be closed any time the government feels like, making it impossible to hold a job. It's no wonder Hamas has an easy time recruiting suicide bombers when they have such a large pool of young men with literally nothing worth living for. This doesn't, of course, make it right, but Israel (and especially the Sharon government) is in a stew of its own making.
It's only zealots who won't recognize that Israel and the US are equally part of the problem.
-JS
The U.S. passed France for the honor of "world's largest arms exporter" right after the Gulf
war.
-JS
Logan airport (the point of origin of two of the flights) is the airport in Boston.
-JS (in Boston)
And many of us where hacking on computers years before we were old enough to drive.
-JS
It depends on the isotope. Po-209, for example, has a half-life of 105 years. I don't have my nuclear physics references on hand, but the decay energies look sufficient to knock of the outer neutron of Beryllium and start the reaction.
Boosted fission bomb designs that use tritium (12 year half-life) instead of deuterium, on the other hand, are probably a real pain to maintain.
-JS