You are correct that helium, given its Maxwellian velocity distribution at Earth's temperature, has a significant-enough fraction of it above escape velocity, so yes, helium gas on earth eventually escapes. So does diatomic hydrogen gas (but not hydrogen compounds eg water and hydrocarbons).
But we DO have alot of helium gas on Earth because much of it is trapped in pockets inside the Earth's crust. It's mined when the oil companies dig for oil and natural gas. In fact, these companies used to release it because it's not economically feasible to capture and sell it. But at least here in the USA the NSF set up some kind of deal with local oil companies to capture and sell the helium gas for cryogenics and other industries.
In this regard, the USA is pretty wasteful with helium gas, filling up balloons at kids parties, venting helium to the atmosphere in laboratories, etc. I've heard about (but not visited) cryogenics labs in other countries where helium is more scarce so they recycle it. In fact, early in grad school before knowing all this, I was also surprised when talking to some Russian students that told me they heard a rumor that breathing helium makes your voice get high. But this is somethign that just about every American kid has tried when they were little.
Gauss's Law says that the gravitational acceleration of a body anywhere in an enclosed sphere is 0.
No it doesn't, re=read the law you linked to. It says the "surface integral of gravitational acceleration" will be zero over any arbitrarily-shaped closed surface, as long as that surface encloses zero mass. You cannot work backwards from this statement to assume that the local gravitational acceleration will be zero.
Simple example. Imagine a closed surface (say a small sphere) 20 feet above the ground (and also assume there's no air inside) such that the surface is closed. Since it encloses no mass, the net acceleration will be zero as summed over the whole sphere. However, any object placed within this hypothetical spherical surface (eg a brick) will fall to the ground.
Depending on your needs, I'd suggest going for the mac mini. It's only $600, so you need to supply your own screen, but given the typical makeup of slashdot crowds I'd assume you have one kicking around somewhere. Mac mini also gives you bluetooth, but you lose the built-in screen.
But if you're really intent on having the built-in screen, that sort of implies you value aesthetics as much or more as cost savings, in which case I'd suggest just getting the normal iMac, which while a bit more expensive, gives you bluetooth and some other things.
As others have noted, the Dell doesn't come with the iSight camera, has a separate tower and screen instead of just a screen, (does the Dell have wireless ethernet?), etc. But the Dell also doesn't come with the iLife software suite either.
For many college students, they'd love to have a machine that you can effectively turn on and start doing cool stuff, like internet chatting with friends, easily making their own web pages (iWeb along with iPhoto, iMovie), jam out with Garage Band, etc. Plus the fact that the iMac is just a screen makes it much more appealing, as every bit of space counts in the typical uni dorm room.
So yeah, you COULD buy a Dell, and then futz around with network cables (assuming it doesn't have wireless), futz around with getting a webcam and mounting it, and then futzing around with installing chatting software, photo and video editing software, loading iTunes, and web development software, all the while worrying about viruses and spyware. Or you could get this iMac and have everything ready to go, just like that "i'm a mac" commercial says, out of the box.
Given the inherent busy-ness of the college schedule, I think many students would easily choose to pay $450 more for the mac solution. It really is a good deal when you consider the package as a whole, which is something that people who haven't really used a mac in the last two years won't understand until they try it. (Spoken as a former linux user since 1998, until last year when my GF switched me over with her mac mini).
Regarding financing, most colleges have their own federal credit unions, which are basically like a private bank. These credit unions usually offer computer loans at rates notably cheaper than the commercial banks, and most likely cheaper than the computer company too. Keep in mind for your next computer purchase.
Seems like you've made up your mind, but you might seriously want to consider the ACTUAL frequency of these problems, or whether it's just a few noisy bloggers. That said, go with the solution you truly think would be happiest, instead of being swayed by bloggers eitherway. Better than living in a world of buyer's remorse.
I'm a recently-converted mac fanboy (used to be a linux zealot until about 1.5 years ago). It seems to me most of the problems are with the latest rev of laptops, which I'm happily naive to. I only have a mac mini (actually it's my girlfriend's), and we haven't had any problems in hardware or software.
The other thing is that I know quite a few people with macbooks and none has yet had any problems as those mentioned on slashdot. My guess is that many mac users tend to be more active online than other laptop users, and hence make much more of a buzz when somethings wrong.
But anyway, my point is that with the desktops (mac mini or imacs) you've got a solid piece of computing machinery.
I remember reading about a decade ago that some wealthy billionaire (I forget which) made a significant charity donation, and was in part saddened that he would no longer be so far up the list that Forbes compiles of the world's richest.
So this says something of the 'rich' mindset, that there's a certain prestige to being atop a high-profile list. In that sense, I hope a new list is started, keeping track of grand total charitable accumulations amongst individuals. This would be something actually admirable to be atop of, and would promote world good too. That way the otherwise stingy rich might be more encouraged to be charitable, without worrying about losing prestiage.
O'Keefe was NOT a scientist, but a business-track administrator, and as such didn't have an intimate understanding of the import of science as a full-blooded scientist does. In other words, he looked at the Hubble telescope as a business project, not as a scientific instrument. Luckily Griffin is completely opposite, he was a scientist and worked his way from science through science management, so has an understanding of both fields pretty well.
Additionally, Columbia was lost on O'Keefe's watch, so he's overcompensating by being excessively cautious for future flights. Unfortunately to the point of compromising scientific fulfillment.
In a nutshell, shows like Simpsons, Family Guy, The Critic, and Futurama make me laugh, and greatly entertain me for their 30 minute duration. Okay, there's a dud episode every now and then, but for the most part they're really fun. And funny. There have been a few scenes from these that would just make me laugh a few days later when I would think about it, for instance.
The fact that it bothers you that Lisa's mental acuity isn't entirely consistent from one episode to the next sort of implies you're greatly outside the demographic they're looking for, in which case I'd suggest stick with the shows that really make you happy. I watch these shows for their comedic value, not for a consistent basis upon which to do a comparative literary analysis.
Similarly, there are shows that other people love that I can't stand at all (eg Everybody Loves Raymond). it's all your own personal tastes. Regarding not liking the Simpsons, my Mom cannot get into the Simpsons either. She's tried and either doesn't get the jokes or just doesn't think they're funny whatsoever.
That said, at the end of your post you mention other shows that are 'really funny'. Can you give an example? I'm not trolling you either, just curious what you find funny.
Regarding the glossy screen, I am wondering two things. Note that I don't use a laptop.
Regarding the glossy screen, I thought this was primarily to compare to Apple's competitors. Ie, I was under the impression that most other laptops are glossy screened, and that many Apple customers were annoyed that Apple only had the matte screen. Are the other laptops you prefer over the macbook also glossy screened?
Secondly, I read somewhere that glossy screens can actually be BETTER than matte screens for use in bright sunlight. Since the screen is flat, you can adjust the screen to not get the sunlight glare in your face. But the matte screen will scatter sunlight no matter which general angle you're at. Additionally, my glass-faced CRT right now is convex-curved, so that means any light behind me will put a glare on the screen, and angling the screen won't fix it since it's convex.
Anyway, I am similar to you in that I didn't like using macs at all until OS X came out, which I now love (I was a linux fan before this). But my GF has a mac mini which I use, and has no hardware problems, so I'm blissfully unaware of laptop hardware issues, and just get to enjoy the OS X goodness.:-)
Bloomberg is pretty liberal in his policies, and rumor has it that when he ran for mayor of NYC, he ran Republican because there were a number of decent Democratic candidates that he didn't think he'd make it past the primary.
You can also see this effect by how Giuliani never endorsed Bloomberg for mayor until only a few weeks before the actual election.
Cuba's a unique place too in that the hugely powerful country right next to it is embargoing the entire island, and effectively dragging other countries into the fray by not letting trading vessels that have stopped at Cuba also stop at the US. When considering your trading partners, most countries opt for the US trade in terms of maximizing profits.
In spite of all this, Cuba has done remarkably well, and is in much better shape than most third-world countries. It also greatly exceeds the US in terms of infant mortality, has the highest literacy rate in Latin America, has twice as many doctors per capita as the US, etc.
Yeah, I know off-topic, but I take any chance I can get to shed some light on this unique nation that most Americans don't know anything about.
You incorrectly deciphered the first word, it's really "Be sure to" instead of "Always". The message made absolutely no sense the way you deciphered it;-)
And yes, I can't believe I actually have neurons somewhere that retain this useless information.
If you had 2.5 million gallons of molasses (or almost any other viscious fluid for that matter) fall suddenly to the ground within a few dozen feet of you, you'd be hard-pressed to get away safely.
Anyway, that said, I used to frequent a building in Boston that used to be almost entirely live-in artist lofts and studio spaces. Until the owner sold it to be knocked-down and replaced with yet another office building. But the interesting thing is that that former loft space was constructed by one of the competitors of the Purity Distilling Company (ie, the company who's molasses tank collapsed). That building was supposedly funded because of all the new business the competitor gained after PDC's molasses setback.
Why's it obnoxious looking? Or, more specifically, any more obnoxious looking than the thousands of other buildings in the city, some of which are designed in artistic fashion, others of which are just thrown together as cheaply as possible?
I feel this "iPod effect" will only cause record labels to enourage their artists to record music that is marketable rather than good (more so than they do already).
I was 100% with you on your whole post, until this last paragraph. And my only comment is to say that already for the past 30+ years the record companies have been choosing marketable music over good music. This is absolutely nothing new, artists (and I mean that in the true sense of the word art) will continue to push the envelope regarding the art of music, and things like concept albums. But the record companies haven't changed at all.
Best example I can give you from back in the day - that horrible three-minute version of The Doors "Light My Fire" where they cut out the great instrumental Manzarek and Krieger jam in the middle. It was all because the record execs didn't believe people would buy an album if the hit song was 7 minutes long. So after the Doors recorded it, the label carefully cut out a 4 minute chunk, for maximal marketing. You can still hear this bastardized version played on the radio on some "Greatest Hits of the 60's, 70's, and 80's" style radio stations. Of course real classic rock stations still play the uncut original.
If they can get decent simple-enough high-tc superconducting lines (ie, with sufficient cryogen cooling, etc) then the only reasons I can think of to stay w/ AC would be ease of stepping the current up/down with transformers. I don't know how efficient DC to DC conversion really is, especially for such a huge scaling factor.
The other reason might be ease of integration with existing substations that are already expecting AC, to be stepped down.
Only for DC current. AC current always has a finite resistive component to it.
Regarding critical current, one could effectively run up a huge potential (eg millions of volts) and send a trickling DC supercurrent to the receiving station. Of course this brings with it all sorts of high voltage problems beyond the typical substations have dealing with high-tension wires. One being the much larger potentials, the other being efficiently converting DC to DC (as opposed to transforming the AC, as traditional power stations do).
The other thing mentioned is very true, regarding catastrophic failure of the lines. I work with superconducting magnets, where to pack a huge magnetic field, you need tiny wires to get enough wrappings in a small space. So we're basically putting 70+ amps through a 22 gauge wire. That's all fine and dandy when the magnet is immersed in liquid helium at 4K, but if you do something dumb, like change the magnet current too quickly or go past the critical current, you can cause part of the magnet to go normal (as opposed to superconducting), in which case that 70A is going to dissipate LOTS of heat, causing more parts of the magnet to go normal, and ultimately cause the whole magnet to go normal, dissipating the induction energy stored in the magnet as heat, which can boil the liquid helium vigourously, build up pressures, damage the magnet and electronics, etc. Very dangerous. Now imagine a similar scenario but in some transission wires at a potential of millions of volts running through a forest or a neighborhood.
Take the Virginia tech g5 supercomputer - that would never have happenned with a closed kernel. The people who made the purchasing decision did so because they could rip Apple's memory management out of the kernel & replace it with one more suited to scietific clustering tasks.
So can that modified kernel remain open source? actually, is their modified kernel even open to begin with?
Slashdot Mirror
But we DO have alot of helium gas on Earth because much of it is trapped in pockets inside the Earth's crust. It's mined when the oil companies dig for oil and natural gas. In fact, these companies used to release it because it's not economically feasible to capture and sell it. But at least here in the USA the NSF set up some kind of deal with local oil companies to capture and sell the helium gas for cryogenics and other industries.
In this regard, the USA is pretty wasteful with helium gas, filling up balloons at kids parties, venting helium to the atmosphere in laboratories, etc. I've heard about (but not visited) cryogenics labs in other countries where helium is more scarce so they recycle it. In fact, early in grad school before knowing all this, I was also surprised when talking to some Russian students that told me they heard a rumor that breathing helium makes your voice get high. But this is somethign that just about every American kid has tried when they were little.
No it doesn't, re=read the law you linked to. It says the "surface integral of gravitational acceleration" will be zero over any arbitrarily-shaped closed surface, as long as that surface encloses zero mass. You cannot work backwards from this statement to assume that the local gravitational acceleration will be zero.
Simple example. Imagine a closed surface (say a small sphere) 20 feet above the ground (and also assume there's no air inside) such that the surface is closed. Since it encloses no mass, the net acceleration will be zero as summed over the whole sphere. However, any object placed within this hypothetical spherical surface (eg a brick) will fall to the ground.
But if you're really intent on having the built-in screen, that sort of implies you value aesthetics as much or more as cost savings, in which case I'd suggest just getting the normal iMac, which while a bit more expensive, gives you bluetooth and some other things.
For many college students, they'd love to have a machine that you can effectively turn on and start doing cool stuff, like internet chatting with friends, easily making their own web pages (iWeb along with iPhoto, iMovie), jam out with Garage Band, etc. Plus the fact that the iMac is just a screen makes it much more appealing, as every bit of space counts in the typical uni dorm room.
So yeah, you COULD buy a Dell, and then futz around with network cables (assuming it doesn't have wireless), futz around with getting a webcam and mounting it, and then futzing around with installing chatting software, photo and video editing software, loading iTunes, and web development software, all the while worrying about viruses and spyware. Or you could get this iMac and have everything ready to go, just like that "i'm a mac" commercial says, out of the box.
Given the inherent busy-ness of the college schedule, I think many students would easily choose to pay $450 more for the mac solution. It really is a good deal when you consider the package as a whole, which is something that people who haven't really used a mac in the last two years won't understand until they try it. (Spoken as a former linux user since 1998, until last year when my GF switched me over with her mac mini).
Regarding financing, most colleges have their own federal credit unions, which are basically like a private bank. These credit unions usually offer computer loans at rates notably cheaper than the commercial banks, and most likely cheaper than the computer company too. Keep in mind for your next computer purchase.
That's funny, I know of no one that's ever had a problem with a first generation Apple notebook either. (I only have desktops, no portables).
Seems like you've made up your mind, but you might seriously want to consider the ACTUAL frequency of these problems, or whether it's just a few noisy bloggers. That said, go with the solution you truly think would be happiest, instead of being swayed by bloggers eitherway. Better than living in a world of buyer's remorse.
The other thing is that I know quite a few people with macbooks and none has yet had any problems as those mentioned on slashdot. My guess is that many mac users tend to be more active online than other laptop users, and hence make much more of a buzz when somethings wrong.
But anyway, my point is that with the desktops (mac mini or imacs) you've got a solid piece of computing machinery.
So this says something of the 'rich' mindset, that there's a certain prestige to being atop a high-profile list. In that sense, I hope a new list is started, keeping track of grand total charitable accumulations amongst individuals. This would be something actually admirable to be atop of, and would promote world good too. That way the otherwise stingy rich might be more encouraged to be charitable, without worrying about losing prestiage.
O'Keefe was NOT a scientist, but a business-track administrator, and as such didn't have an intimate understanding of the import of science as a full-blooded scientist does. In other words, he looked at the Hubble telescope as a business project, not as a scientific instrument. Luckily Griffin is completely opposite, he was a scientist and worked his way from science through science management, so has an understanding of both fields pretty well.
Additionally, Columbia was lost on O'Keefe's watch, so he's overcompensating by being excessively cautious for future flights. Unfortunately to the point of compromising scientific fulfillment.
Dude, why would you want to stick a pin in a kid?
In a nutshell, shows like Simpsons, Family Guy, The Critic, and Futurama make me laugh, and greatly entertain me for their 30 minute duration. Okay, there's a dud episode every now and then, but for the most part they're really fun. And funny. There have been a few scenes from these that would just make me laugh a few days later when I would think about it, for instance.
The fact that it bothers you that Lisa's mental acuity isn't entirely consistent from one episode to the next sort of implies you're greatly outside the demographic they're looking for, in which case I'd suggest stick with the shows that really make you happy. I watch these shows for their comedic value, not for a consistent basis upon which to do a comparative literary analysis.
Similarly, there are shows that other people love that I can't stand at all (eg Everybody Loves Raymond). it's all your own personal tastes. Regarding not liking the Simpsons, my Mom cannot get into the Simpsons either. She's tried and either doesn't get the jokes or just doesn't think they're funny whatsoever.
That said, at the end of your post you mention other shows that are 'really funny'. Can you give an example? I'm not trolling you either, just curious what you find funny.
Regarding the glossy screen, I thought this was primarily to compare to Apple's competitors. Ie, I was under the impression that most other laptops are glossy screened, and that many Apple customers were annoyed that Apple only had the matte screen. Are the other laptops you prefer over the macbook also glossy screened?
Secondly, I read somewhere that glossy screens can actually be BETTER than matte screens for use in bright sunlight. Since the screen is flat, you can adjust the screen to not get the sunlight glare in your face. But the matte screen will scatter sunlight no matter which general angle you're at. Additionally, my glass-faced CRT right now is convex-curved, so that means any light behind me will put a glare on the screen, and angling the screen won't fix it since it's convex.
Anyway, I am similar to you in that I didn't like using macs at all until OS X came out, which I now love (I was a linux fan before this). But my GF has a mac mini which I use, and has no hardware problems, so I'm blissfully unaware of laptop hardware issues, and just get to enjoy the OS X goodness. :-)
You can also see this effect by how Giuliani never endorsed Bloomberg for mayor until only a few weeks before the actual election.
In spite of all this, Cuba has done remarkably well, and is in much better shape than most third-world countries. It also greatly exceeds the US in terms of infant mortality, has the highest literacy rate in Latin America, has twice as many doctors per capita as the US, etc.
Yeah, I know off-topic, but I take any chance I can get to shed some light on this unique nation that most Americans don't know anything about.
I just saw An Inconvenient Truth (a movie I recommend any self-respecting geek to see, whether you believe in global warming or not). In the film Gore lays out an amazing Keynote presentation on global warming.
I wish I had mod points to mod you up just for using the phrase "virtual dildonics"!
And yes, I can't believe I actually have neurons somewhere that retain this useless information.
Anyway, that said, I used to frequent a building in Boston that used to be almost entirely live-in artist lofts and studio spaces. Until the owner sold it to be knocked-down and replaced with yet another office building. But the interesting thing is that that former loft space was constructed by one of the competitors of the Purity Distilling Company (ie, the company who's molasses tank collapsed). That building was supposedly funded because of all the new business the competitor gained after PDC's molasses setback.
Why's it obnoxious looking? Or, more specifically, any more obnoxious looking than the thousands of other buildings in the city, some of which are designed in artistic fashion, others of which are just thrown together as cheaply as possible?
I was 100% with you on your whole post, until this last paragraph. And my only comment is to say that already for the past 30+ years the record companies have been choosing marketable music over good music. This is absolutely nothing new, artists (and I mean that in the true sense of the word art) will continue to push the envelope regarding the art of music, and things like concept albums. But the record companies haven't changed at all.
Best example I can give you from back in the day - that horrible three-minute version of The Doors "Light My Fire" where they cut out the great instrumental Manzarek and Krieger jam in the middle. It was all because the record execs didn't believe people would buy an album if the hit song was 7 minutes long. So after the Doors recorded it, the label carefully cut out a 4 minute chunk, for maximal marketing. You can still hear this bastardized version played on the radio on some "Greatest Hits of the 60's, 70's, and 80's" style radio stations. Of course real classic rock stations still play the uncut original.
The other reason might be ease of integration with existing substations that are already expecting AC, to be stepped down.
Only for DC current. AC current always has a finite resistive component to it.
Regarding critical current, one could effectively run up a huge potential (eg millions of volts) and send a trickling DC supercurrent to the receiving station. Of course this brings with it all sorts of high voltage problems beyond the typical substations have dealing with high-tension wires. One being the much larger potentials, the other being efficiently converting DC to DC (as opposed to transforming the AC, as traditional power stations do).
The other thing mentioned is very true, regarding catastrophic failure of the lines. I work with superconducting magnets, where to pack a huge magnetic field, you need tiny wires to get enough wrappings in a small space. So we're basically putting 70+ amps through a 22 gauge wire. That's all fine and dandy when the magnet is immersed in liquid helium at 4K, but if you do something dumb, like change the magnet current too quickly or go past the critical current, you can cause part of the magnet to go normal (as opposed to superconducting), in which case that 70A is going to dissipate LOTS of heat, causing more parts of the magnet to go normal, and ultimately cause the whole magnet to go normal, dissipating the induction energy stored in the magnet as heat, which can boil the liquid helium vigourously, build up pressures, damage the magnet and electronics, etc. Very dangerous. Now imagine a similar scenario but in some transission wires at a potential of millions of volts running through a forest or a neighborhood.
So can that modified kernel remain open source? actually, is their modified kernel even open to begin with?
Why would that be? Apple is still selling pre-packaged clusters. Another poster mentioned the switch to Intel might change things, what's your take?