The first thing employers care about is work experience . They can call your last employer and ask how good you were. In 30 seconds they can make a decision. The second most important facto they consider is your real tertiary qualifications.
Actually, a prospective employer can only call your references to ask how good you were at your job. Your employer is barred from just about any kind of comment about you except to verify that you work(ed) there, the dates of your employment, and maybe your salary. This is also the reason that if you list any of your current coworkers or supervisors as references, it puts them in a tight spot and they feel reluctant to talk much about you (good or bad) if contacted.
You are referring to Kittinger's 76,000 ft jump. He got tangled in his drogue (it wrapped around his neck) and passed out. An automatically deployed emergency chute saved his life. On his 102,000 ft jump he was in danger of losing his hand because his glove depressurized.
The 40 isn't the largest balloon out there, it is (just as you stated) the largest that is part of Raven's "off the shelf" stock. I think they used to make 52's, and I'm sure if you come with the proper amount of money, they can accomodate larger sizes. I'm not sure who makes these balloons overseas.
The goal of 40km should not be a problem for these guys if they have a successful launch. I was part of a research team that launched a 2000 lb payload to over 42 km on a 40 Mcft balloon, so if these guys get a larger balloon than that, it should be that much easier. The manned balloon altitude record, by the way, is 113,740 ft set in 1961 from the Strato-Lab V platform by US Navy pilots Malcolm Ross and Vic Parther.
An excellent history of setting the manned balloon altitude record can be found in David DeVorkin's Race to the Stratosphere.
Actually, this is in line with the laws of physics. For an object that is shaped roughly like a rectangular block or ellipsoid (e.g., something that is skinnier than it is wide, and again as it is long (such as a book, a blackboard eraser, or a car)), rotation on the body is stable about the principle axes that have the largest and smallest moment of inertia. Rotation about the other axis (in this case, the axis that passes through the car doors) is unstable and results in an induced rotation about one of the other principle axes. For an object like a book or a piece of 2x4, you cannot flip it without it doing a half twist.
And unlike a photocopier, which manages to prevent many improper uses through cost and inconvenience, this machine would be a casual music/software pirate's dream.
I fail to see how $7 a copy agrees with this statement. I can copy CDs for far less than $7 a copy and in a much more convenient setting than doing it from this machine. In fact, I would argue that what the machine charges as well as where it seems to be located would "manage to prevent many improper uses through cost and inconvenience."
Thank you for the very detailed response. I hope the moderator gods smile favorable on you.:)
I am certainly going to try TeXmacs. I am a LaTeX guy at heart and I have always thought the beauty of it is that it does exactly what you tell it to do, and you can really make it stand on its head if you wanted (where the really arcane stuff you'd add with TeX commands); maybe I really don't want either single, double, or 1.5 space lines---I want 0.8 spaced lines dammit!
I always looked at TeX vs WYSIWYG as like C programming vs VisualBasic, where the former isn't cute or restrictive like the latter. I look forward to comparing TeXmacs to LaTeX.
I see a lot of comments about how XML is much better than TeX/LaTeX because you only need to write the text and all the formatting is handled in the DTD; if you want a different layout, you find a different DTD. Or that TeX/LaTeX is as horrible as HTML because you have to explicitly put in all the formatting. Neither is my experience with TeX/LaTeX. When I wrote my dissertation I never worried one bit about any formatting because I used the university-supplied LaTeX style format. I just wrote the text, ran it through LaTeX and out came the beautiful format. Also many professional societies and journals provide a LaTeX style file so the author doesn't have to worry about figuring out how to get the document layout correct. Also, if I want to throw together a quick document without thinking about it, I use the default article style. It is all platform independent too. And you can also define your own tags, so to speak, very easily.
Since I know very little about XML, could someone who knows both XML and TeX/LaTeX clue me in?
A very nice, recent article ...
on
Linux Tuning Tricks?
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· Score: 5, Interesting
Linux Journal has a nice article on fine-tuning your system (doing things like recompiling the kernel with the best compiler options and optimizations (it also covers hdparam).
My only gripe with LJ articles is that, even if you put them in print mode, they still run off the end of my paper when I print them.
This is straight-up physics of waves, and as such is not unexpected. From time to time another experiment is done and it gets widely reported and misunderstood (even by scientists that should know better, but who have forgot their freshman/sophomore level physics).
This is the basic misunderstanding of what the phase, group, and signal velocities of a wave system are. The bottom line is that you cannot send information using these superluminal signals, so there are no time travel/relativity problems. A nice Java applet showing this is here.
Does anyone know the history of this disability? I have always wondered why it has become such a problem in the last 10 years when there have been typing pools around for more than 100 years.
Maybe this confirms my thinking that the mouse is an ergonomic nightmare and one should stay away from GUI-centric editors and do it all on the keyboard.
College Football, what else is there?
on
New Years Marathons
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· Score: 2, Informative
This is truely the best time of the year. Five games (Humanitarian, Sun, Silicon Valley Classic, Liberty, and Peach) on today, and eight more in the coming few days.
I would be more inclined to say that the fate of the Universe is dependent on whether neutrinos have mass. There are far more neutrinos than any other matter predicted or known (except for photons). If the neutrino has even a tiny mass, the result is most likely a closed Universe.
CRN ran an industry survey on certifications. The results can be found here.
One interesting result was that the fastest growing certifications were Linux Professional Institute Certified (LPIC) Level 1 and the Red Hat Certified Engineer (RHCE).
I have great concern regarding the emphasis and quality of science and mathematics teaching in the primary and secondary schools in the US. I believe much more can and should be done to improve the teaching, retention, and understanding for these subjects from K-12. Having said that, I looked at the stats on the science test results and things basically have not changed, so I think that, based on the test results, it is a bit misleading to say that we are doing worse as a nation.
The score changes from the 1996 test show only a statistical difference in the 12th grade results, and these differences are marginal at best. Even within the statistically different 12th grade results, the only statistical change was in the group that scored in the 50-percentile (a promising stat from that figure is that there was a statictically significant increase in the top performing 8th graders).
One graph that I found troubling was the one showing the numbers above and below basic proficiency levels for the 12th graders, where the numbers falling below understanding the basics increased. We can hope that this is a statistical fluctuation and not the start of a trend.
By the way, the web site is very impressive in how much information is presented from the test question to the error on the test results. My biggest beef with statistics reported in the media is that they either never give error bars, or they'll ignore the errors; they'll report political poll results as one candidate ahead in the polls even if that person is ahead by less than the margin of error (this leads to the whole topic of basic ignorance of relative risk and you don't want to get me going on that rant!).
I think that some questions benefit from the personal feedback one gets here. The nature of 'Ask Slashdot' permits a Google query on pretty much any subject; however, what a Google search doesn't give you is the possiblility that someone with experience will respond to the post. In this particular case, perhaps someone who builds RAID-controlled white boxes will have information or advice that is not found in the online reviews.
If you ban questions that an answer can be found on Google, then you'd pretty much have to drop askslashdot as a section. For instance, take the last three questions:
I admit that I personally turn to Google first, but if the information one gets back is overwhelming, confusing, or contradictory, then I don't have a problem sending the question here.
I believe current thinking on these collisions is a planet being struck by a very sizeable object. I presume these kind of collisions are highly inelastic, so I think you have to be careful about thinking of the struck planet being kicked into significantly different orbits. I believe that the modelling of these things show that most of the kinetic energy goes into friction that liquefies the planet. There is more and more evidence that the Moon was formed when a Mars-sized object hit the Earth. A nice link that shows the results of a model as well as discussing some of the stuff mentioned above can be found here.
Incidentally, some believe that Charon was formed when something struck Pluto in a similar fashion.
Remember that you can't "lose" gravity. Even when the pieces are separated, if there is nothing else to continually draw them apart they will still want to reassemble through mutual attraction. It is like watching an exploding firework; after the explosion all the pieces are moving with the same center of mass. In the case of the firework the aerodynamic drag on the little pieces as well as wanting to fall back to Earth keeps the little pieces from reassembling. If the firework was exploded in space, if the initial explosion was not large enough to give the pieces enough escape velocity (that is, enough velocity to escape the gravitational attraction from all the other pieces), the firework would eventually fall back together.
It all depends on what the local environment is like. For instance, the rings around the planets (most notably Saturn) are composed of a bunch of material that doesn't seem to want to reassemble (at least on the several hundred year timescales that we have observed it), and it is believed that the shepherd moons provide enough disturbance to keep the ring material in a ring (actually they keep the material from spreading out uniformly; it is the Roche limit that keeps them from clumping).
Young's DS experiment does work at extremely low light intensities which is why it is one of the classic examples demonstrating the wave/particle duality and/or uncertainty principle in QM. The wave-like interference is seen in the double slit experiment even if you turn the light intensity all the way down so that you are emitting single photons. I (or anyone else) can't explain it any better than Richard Feynman in his classic Feynman Lectures, but I can point you to the results of the DS experiment for very low intensities here.
By the way, diffraction gratings are completely explained within the particle/wave nature of matter, which is why confirmation of the Kapitza-Dirac effect is scientifically interesting but not unexpected. QM doesn't explain everything as waves, the wave/particle duality arises from the fact that all matter has an associated wavelength, the DeBroglie wavelength. Wavelike behavior becomes evident when matter is subjected to dimensions that are on the order of this wavelength (for instance, you won't see a diffraction pattern from light if the slit is too large, and in the case of the Kapitza-Dirac effect, standing waves from the laser create an appropriately spaced diffraction grating to act on the DeBroglie wavelength of the electrons they used).
A basic physics experiment that illustrates the wave nature of light involves placing a screen with two slits in it at a distance from a point source of light and placing a second screen beyond the first. Instead of two bars of light appearing on the second screen directly in line with the light and the slits, multiple light bars appear across the second screen. That's because the slits diffract the light and the bars mark the convergence of light waves. It's Quantum Mechanics 101.
That is the explanation of the Young's double slit experiment, and that is High School physics.
By the way, unless the level of undergraduate quantum mechanics has changed since I took it, I don't think Feynman path integrals are in QM 101.
The U. Nebraska press release says that this is the first time this effect has been observed, but the post has a link to a Phys. Rev. A article (Dynamical diffraction of atomic matter waves by crystals of light) that was submitted in 1998 and published in July 1999 that talks about observing this effect.
There is also a 1986 PRL article, Diffraction of atoms by light - The near-resonant Kapitza-Dirac effect, which has as the abstract:
The Kapitza-Dirac effect is observed in the scattering of sodium atoms by a near-resonant standing-wave laser field. The data clearly show diffraction peaks of the atomic momentum transfer at even multiples of the photon momentum. Theoretical predictions for an off-resonant, adiabatic interaction with a two-state system are in reasonable agreement with the data.
It isn't clear whether a special case of the Kapitza-Dirac effect was first observed (e.g., the first time observed using an electron beam), but it seems that it wasn't the first time this effect was seen in the lab. (The press release also mentions that the basic physics demo of the double-slit experiment was Quantum Mechanics 101, when it really is High School Physics 101).
Slashdot Mirror
I'm sorry, but shouldn't that be GNU/Crystal Space and GNU/CEL? :)
You are referring to Kittinger's 76,000 ft jump. He got tangled in his drogue (it wrapped around his neck) and passed out. An automatically deployed emergency chute saved his life. On his 102,000 ft jump he was in danger of losing his hand because his glove depressurized.
The goal of 40km should not be a problem for these guys if they have a successful launch. I was part of a research team that launched a 2000 lb payload to over 42 km on a 40 Mcft balloon, so if these guys get a larger balloon than that, it should be that much easier. The manned balloon altitude record, by the way, is 113,740 ft set in 1961 from the Strato-Lab V platform by US Navy pilots Malcolm Ross and Vic Parther.
An excellent history of setting the manned balloon altitude record can be found in David DeVorkin's Race to the Stratosphere .
I am certainly going to try TeXmacs. I am a LaTeX guy at heart and I have always thought the beauty of it is that it does exactly what you tell it to do, and you can really make it stand on its head if you wanted (where the really arcane stuff you'd add with TeX commands); maybe I really don't want either single, double, or 1.5 space lines---I want 0.8 spaced lines dammit!
I always looked at TeX vs WYSIWYG as like C programming vs VisualBasic, where the former isn't cute or restrictive like the latter. I look forward to comparing TeXmacs to LaTeX.
Since I know very little about XML, could someone who knows both XML and TeX/LaTeX clue me in?
My only gripe with LJ articles is that, even if you put them in print mode, they still run off the end of my paper when I print them.
This is the basic misunderstanding of what the phase, group, and signal velocities of a wave system are. The bottom line is that you cannot send information using these superluminal signals, so there are no time travel/relativity problems. A nice Java applet showing this is here.
Are you suggesting that he wouldn't be able to get a coaching job at Notre Dame?
Maybe this confirms my thinking that the mouse is an ergonomic nightmare and one should stay away from GUI-centric editors and do it all on the keyboard.
This is truely the best time of the year. Five games (Humanitarian, Sun, Silicon Valley Classic, Liberty, and Peach) on today, and eight more in the coming few days.
I would be more inclined to say that the fate of the Universe is dependent on whether neutrinos have mass. There are far more neutrinos than any other matter predicted or known (except for photons). If the neutrino has even a tiny mass, the result is most likely a closed Universe.
One interesting result was that the fastest growing certifications were Linux Professional Institute Certified (LPIC) Level 1 and the Red Hat Certified Engineer (RHCE).
The score changes from the 1996 test show only a statistical difference in the 12th grade results, and these differences are marginal at best. Even within the statistically different 12th grade results, the only statistical change was in the group that scored in the 50-percentile (a promising stat from that figure is that there was a statictically significant increase in the top performing 8th graders).
One graph that I found troubling was the one showing the numbers above and below basic proficiency levels for the 12th graders, where the numbers falling below understanding the basics increased. We can hope that this is a statistical fluctuation and not the start of a trend.
By the way, the web site is very impressive in how much information is presented from the test question to the error on the test results. My biggest beef with statistics reported in the media is that they either never give error bars, or they'll ignore the errors; they'll report political poll results as one candidate ahead in the polls even if that person is ahead by less than the margin of error (this leads to the whole topic of basic ignorance of relative risk and you don't want to get me going on that rant!).
If you ban questions that an answer can be found on Google, then you'd pretty much have to drop askslashdot as a section. For instance, take the last three questions:
Colocation facilities in Southern California
Xbox as a DVD player
Office culture for IT employees
I admit that I personally turn to Google first, but if the information one gets back is overwhelming, confusing, or contradictory, then I don't have a problem sending the question here.
Incidentally, some believe that Charon was formed when something struck Pluto in a similar fashion.
It all depends on what the local environment is like. For instance, the rings around the planets (most notably Saturn) are composed of a bunch of material that doesn't seem to want to reassemble (at least on the several hundred year timescales that we have observed it), and it is believed that the shepherd moons provide enough disturbance to keep the ring material in a ring (actually they keep the material from spreading out uniformly; it is the Roche limit that keeps them from clumping).
By the way, diffraction gratings are completely explained within the particle/wave nature of matter, which is why confirmation of the Kapitza-Dirac effect is scientifically interesting but not unexpected. QM doesn't explain everything as waves, the wave/particle duality arises from the fact that all matter has an associated wavelength, the DeBroglie wavelength. Wavelike behavior becomes evident when matter is subjected to dimensions that are on the order of this wavelength (for instance, you won't see a diffraction pattern from light if the slit is too large, and in the case of the Kapitza-Dirac effect, standing waves from the laser create an appropriately spaced diffraction grating to act on the DeBroglie wavelength of the electrons they used).
That is the explanation of the Young's double slit experiment, and that is High School physics.
By the way, unless the level of undergraduate quantum mechanics has changed since I took it, I don't think Feynman path integrals are in QM 101.
There is also a 1986 PRL article, Diffraction of atoms by light - The near-resonant Kapitza-Dirac effect, which has as the abstract:
It isn't clear whether a special case of the Kapitza-Dirac effect was first observed (e.g., the first time observed using an electron beam), but it seems that it wasn't the first time this effect was seen in the lab. (The press release also mentions that the basic physics demo of the double-slit experiment was Quantum Mechanics 101, when it really is High School Physics 101).
Another place to read about this (complete with MPEGs of the self-healing crack) is at The PhysicsWeb.
Here's a pdf article from The Industrial Physicist that talks not only about ion engines, but also other future engine concepts.