The [offline] article I read on this indicated that this case was unusual in that the girl did not have your standard type 1 diabetes but had developed it due to an inflammation of the pancreas when she was younger. As a result her immune system was not attacking her beta cells so this case is rather different from that in most type 1s whose bodies would attack implanted cells normally.
This is a trivial statement. If n flips has m total disparities, n+x flips will have between m and m+x disparities. It is therefore impossible for the total number of disparities to decrease, and almost guaranteed that it will increase.
Except that one disparity can counteract another. A tail on a coinflip is an anti-head, if you like.
Imagine your first n flips come up heads. You then have m=n 'disparities' as you call them.
You flip a further x=n times which come up tails. You have no disparities remaining.
It wasn't uncommon for leaves to be added to statues in relatively modern times (ie Victorian), and perhaps more recently for them to be removed again to reveal the original statue.
Postscript is probably subject to more controls than PDF. Take the use of Display PDF rather than Display Postscript in OSX for example - Ars Technica mentions the licensing fees that Apple would have had to pay.
Surely we're better off with pdf than gzipped ps?
Firstly, it's not "principle", it's "Principal", and even if it was, it would be "priciple's office". Secondly, I doubt Oxford has a Principal. The normal head of a UK university is the Vice-Chancellor, but Oxford like to do things differently so maybe it's a Rector.
Quite right, and they're not 'kids' either - they're adults. The head of OU is the Vice-Chancellor but he'll be far too busy for such things as this. Appropriate people to talk to (the chain of command if you like) would be college or university IT support staff, college officials and lastly the Proctors - those responsible for student discipline and the actions being taken on these individuals.
There's certainly a few genuine ones around. I believe a hotel in Torquay or somewhere has one. They're probably easily distinguished from replicas by whether you can actually fit a small man inside to operate it.
Third page of the article at LinuxDevCenter.com - figure 6. http://www.linuxdevcenter.com/linux/2004/06/10 /gra phics/visio_5.gif
Terminal window in the background. The author is using xhost along with some hairy ssh command line. Is there a good reason for this and not using ssh's built in X forwarding?
No, it won't take 15% of the sky in one shot. 15% of the sky is about 6200 square degrees, or 8 x 10^10 square arcseconds, according to 'units'. That's roughly a pixel 13 arcseconds across if it did, which is pretty much useless for the kind of science they'll want to do with it I expect.
What it will do is take a large number of shots of small bits of sky over a long period of time until it has covered 15% of the sky.
It'll probably pick up the occasional asteroid as part of its survey, but I doubt it'll be efficient at spotting them at all.
How about you look into deep space and see absorption or emission lines corresponding to carbon in ways that show that way back in time carbon must have been stable to exist in sufficient quantity to produce those features?
I very much doubt that the stability of carbon has varied much in the lifetime of the universe.
Yes, that's what I heard too. I think they might be trying to get some data from UVES at the European Southern Observatory, and that should be a good alternative test.
The Oklo reactor you refer to tests a quantity that depends on alpha, and some other combination of parameters. This makes it a more ambiguous test as, for example, a shift in the proton/electron mass ratio or something could affect the results.
Nah, neutrinos are associated with electrons, muons and tau particles, so there's only the three kinds (and we're sure there *are* only three). There isn't room for a ton-mass neutrino in the scheme of things.
There's probably a few other supersymmetric particles that these things might be, but they ain't neutrinos.
I'm somewhat surprised that noone has pointed this out yet: Einstein's theories of relativity are both based in part on the idea that the laws of physics ARE completely identical on a global scale. To claim that Einstein's theory of relativity tells us that even the physical laws of our universe only apply locally. is not even remotely correct.
Furthermore And as I understand it, quantum physics tells us that nothing is impossible, just very very very unlikely. is also quite wrong. Quantum mechanics definitely does state that some things are impossible.
1. You walk around on a carpet, stealing electrons from it and giving it a charge of say, +x, and building up a negative charge on yourself of -x. You then touch the carpet, causing all those electrons to leap off you and arc back to the carpet. You could also touch a neutral piece of electronics (charge 0), which would accept half of your electrons (give or take) and fry itself.
2. You walk around on a grounded carpet, stealing electrons from it and building a charge on yourself. However, since it's grounded there is an unlimited number to steal. Furthermore, since the carpet isn't building up a huge negative charge, it has no problem giving up more electrons (say -2x). Thus, you could conceivably build up a *bigger* charge than before. This would result in more of a shock when transferring the charge back to a neutral piece of equipment.
Am I missing something here?
Yes - look back at what you said about the neutral electronics. The grounded carpet will accept all your electrons back in just the same way - but at the end it will have virtually the same charge density.
I really don't think anyone is going to throw away the principle of the conservation of momentum. Its far too fundamental to throw away just like that. It would have all kinds of consequences that would be nasty (isn't conservation of momentum tied to the translational isotropy of space? Sounds like we wouldn't want to lose that on the basis of the magnetic equivalent of a jumping bean).
Its pretty clear that the momentum the magnet gains is either countered by the momentum given to the metal, or to momentum put into the electromagnetic field (which is perfectly valid - photons have momentum). There aren't any other possibilities worth wasting time thinking about for now (Occam's Razor is good for this kind of thing).
I wouldn't rely on this as any kind of space drive though - you've pretty much got a 'rocket' which either chucks out metal or chucks out momentum into the electromagnetic field, and chances are a laser would be far more efficient at the latter as its more directional than a coil of superconductor (though thats just a guess). Its interesting, but I very much doubt its useful.
By the way, I know a lot of this post is redundant, but I thought a lot of it was worth repeating because its a confusing issue. Mod me down if you like.
Right... I just had a physicist from CERN explain this to me...
The synchrotron radiation from a charged particle (like a proton or electron) is proportional to the gamma-factor (the time-dilation factor if you like) to the fourth power. This means when you do all the maths that the LHC can reach energies of approximately 2000^4 times greater than the LEP.
This is because the limiting factor is not exactly the energy pumped in but the energy that is radiated away, if you see what I mean...
Its not brilliantly clear because I've been drinking rather heavily tonight, but basically the larger mass of the proton means it has a lower time-dilation factor for the same energy and so loses less energy as it goes round the collider.
I know I've trivialised it a fair bit, but this is the best way I can see to explain it in what are loosely called laymans' terms.
Its not the energy that the collider can provide... but the energy that the particle loses that limits the ability of us to build bigger colliders.
Re:Security is only as good as its inventor
on
Quantum Security
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· Score: 3
This isn't true in this case. We're talking about the transmission of One-Time Pads here, and they are unbreakable. The problem is keeping the pads secure, as although the keys can't be guessed in this case, they can still be stolen after the transmission.
As the linked article points out, the quantum methods mean you can guarantee the transmission is secure, but not a lot else. These cryptographic methods have all the security of other methods and then some. The only weakness (and I really mean only) is that the keys are still subject to theft if you aren't very careful.
Re:Great education opportunity....
on
Quantum Security
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· Score: 1
A maths degree would definitely be the way to go. The basic algorithms you'd need probably wouldn't require a full CS course, and the maths would easily stand you in good stead to make learning the quantum mechanics you need easy, and you might even find it on the course as part of applied maths or something.
Yup... basically they use the random data from quantum processes (random data, which as an earlier post pointed out goes to both parties) to generate a One-Time Pad.
One-Time Pads are guaranteed unbreakable, since amongst the set of keys that the encrypter might have used are those keys which will generate meaningful but wrong messages of the same length.
eg: I could encrypt "hello world" using a simple OTP and if you tried to crack it you would find amongst your possible decryptions every meaningful sentence or word of 11 characters (assuming a fairly basic XOR encryption). This would include "Hello Frank", "Big fat gun" and so on.
Furthermore, Quantum Cryptography means I can essentially guarantee that you won't be able to listen in on the transmission channel of this OTP, so I can be sure that the pad will get to the person I'm communicating with in a secure manner.
Firstly, MS are surely negligent and have only themselves to blame if they spotted the break-in several weeks ago (told the Times that the break-in was first noticed when irregular new accounts began appearing more than a week ago.) and did nothing to pull the plug. They could easily have physically seperated systems containing source code from those connected to the net. If code was stolen in these circumstances they only have themselves to blame.
Secondly, what is this rubbish about a 'brief look'? We all know it'd take nothing more than use of a screenshot facility to preserve the data to read back at ones leisure.
Thirdly, considering the venom with which MS is likely to chase down anyone in possession of the source code, would it not be worthwhile using a random one-time-pad to encrypt the code and have two people post, independently, the two halves without making claim to it containing MS code? Then a third party could point out that the code can be obtained by the appropriate XORing, and noone (except perhaps the third party, who is doing little more than posting a link) can be blamed, as both the first two have posted nothing more than random data?
So can free software programmers now sue Microsoft for all the extra legal costs incurred as a result of their useless security?
If so I think we'd best get a list of the most expensive lawyers around to maximise the damage!
I can see their faces now.... with Microsoft having to pay programmers working under the GPL, for having to make sure they wouldn't have to pay Microsoft!
Slashdot Mirror
Oh yeah, as it said in the second FA.
The [offline] article I read on this indicated that this case was unusual in that the girl did not have your standard type 1 diabetes but had developed it due to an inflammation of the pancreas when she was younger. As a result her immune system was not attacking her beta cells so this case is rather different from that in most type 1s whose bodies would attack implanted cells normally.
The Chandrasekhar limit is 1.4 solar masses, and is quite irrelevant to the lower limit on the mass of hydrogen which will form a star.
This star has no bearing on the Chandrasekhar limit.
This is a trivial statement. If n flips has m total disparities, n+x flips will have between m and m+x disparities. It is therefore impossible for the total number of disparities to decrease, and almost guaranteed that it will increase.
Except that one disparity can counteract another. A tail on a coinflip is an anti-head, if you like.
Imagine your first n flips come up heads. You then have m=n 'disparities' as you call them.
You flip a further x=n times which come up tails. You have no disparities remaining.
David, for example, suffered this fate.
Postscript is probably subject to more controls than PDF. Take the use of Display PDF rather than Display Postscript in OSX for example - Ars Technica mentions the licensing fees that Apple would have had to pay. Surely we're better off with pdf than gzipped ps?
Firstly, it's not "principle", it's "Principal", and even if it was, it would be "priciple's office". Secondly, I doubt Oxford has a Principal. The normal head of a UK university is the Vice-Chancellor, but Oxford like to do things differently so maybe it's a Rector.
Quite right, and they're not 'kids' either - they're adults. The head of OU is the Vice-Chancellor but he'll be far too busy for such things as this. Appropriate people to talk to (the chain of command if you like) would be college or university IT support staff, college officials and lastly the Proctors - those responsible for student discipline and the actions being taken on these individuals.
Errr no. That was one student's perspective, not Compsoc's.
There's certainly a few genuine ones around. I believe a hotel in Torquay or somewhere has one. They're probably easily distinguished from replicas by whether you can actually fit a small man inside to operate it.
Third page of the article at LinuxDevCenter.com - figure 6.0 /gra phics/visio_5.gif
http://www.linuxdevcenter.com/linux/2004/06/1
Terminal window in the background. The author is using xhost along with some hairy ssh command line. Is there a good reason for this and not using ssh's built in X forwarding?
No, it won't take 15% of the sky in one shot. 15% of the sky is about 6200 square degrees, or 8 x 10^10 square arcseconds, according to 'units'. That's roughly a pixel 13 arcseconds across if it did, which is pretty much useless for the kind of science they'll want to do with it I expect.
What it will do is take a large number of shots of small bits of sky over a long period of time until it has covered 15% of the sky.
It'll probably pick up the occasional asteroid as part of its survey, but I doubt it'll be efficient at spotting them at all.
No, the Valeyard was 'somewhere between the twelfth and thirteenth regenerations' or something like that.
I very much doubt that the stability of carbon has varied much in the lifetime of the universe.
Yes, that's what I heard too. I think they might be trying to get some data from UVES at the European Southern Observatory, and that should be a good alternative test.
The Oklo reactor you refer to tests a quantity that depends on alpha, and some other combination of parameters. This makes it a more ambiguous test as, for example, a shift in the proton/electron mass ratio or something could affect the results.
Nah, neutrinos are associated with electrons, muons and tau particles, so there's only the three kinds (and we're sure there *are* only three). There isn't room for a ton-mass neutrino in the scheme of things.
There's probably a few other supersymmetric particles that these things might be, but they ain't neutrinos.
I'm somewhat surprised that noone has pointed this out yet: Einstein's theories of relativity are both based in part on the idea that the laws of physics ARE completely identical on a global scale. To claim that Einstein's theory of relativity tells us that even the physical laws of our universe only apply locally. is not even remotely correct. Furthermore And as I understand it, quantum physics tells us that nothing is impossible, just very very very unlikely. is also quite wrong. Quantum mechanics definitely does state that some things are impossible.
Yes - look back at what you said about the neutral electronics. The grounded carpet will accept all your electrons back in just the same way - but at the end it will have virtually the same charge density.
Its pretty clear that the momentum the magnet gains is either countered by the momentum given to the metal, or to momentum put into the electromagnetic field (which is perfectly valid - photons have momentum). There aren't any other possibilities worth wasting time thinking about for now (Occam's Razor is good for this kind of thing).
I wouldn't rely on this as any kind of space drive though - you've pretty much got a 'rocket' which either chucks out metal or chucks out momentum into the electromagnetic field, and chances are a laser would be far more efficient at the latter as its more directional than a coil of superconductor (though thats just a guess). Its interesting, but I very much doubt its useful.
By the way, I know a lot of this post is redundant, but I thought a lot of it was worth repeating because its a confusing issue. Mod me down if you like.
The synchrotron radiation from a charged particle (like a proton or electron) is proportional to the gamma-factor (the time-dilation factor if you like) to the fourth power. This means when you do all the maths that the LHC can reach energies of approximately 2000^4 times greater than the LEP.
This is because the limiting factor is not exactly the energy pumped in but the energy that is radiated away, if you see what I mean...
Its not brilliantly clear because I've been drinking rather heavily tonight, but basically the larger mass of the proton means it has a lower time-dilation factor for the same energy and so loses less energy as it goes round the collider.
I know I've trivialised it a fair bit, but this is the best way I can see to explain it in what are loosely called laymans' terms.
Its not the energy that the collider can provide... but the energy that the particle loses that limits the ability of us to build bigger colliders.
As the linked article points out, the quantum methods mean you can guarantee the transmission is secure, but not a lot else. These cryptographic methods have all the security of other methods and then some. The only weakness (and I really mean only) is that the keys are still subject to theft if you aren't very careful.
A maths degree would definitely be the way to go. The basic algorithms you'd need probably wouldn't require a full CS course, and the maths would easily stand you in good stead to make learning the quantum mechanics you need easy, and you might even find it on the course as part of applied maths or something.
One-Time Pads are guaranteed unbreakable, since amongst the set of keys that the encrypter might have used are those keys which will generate meaningful but wrong messages of the same length.
eg: I could encrypt "hello world" using a simple OTP and if you tried to crack it you would find amongst your possible decryptions every meaningful sentence or word of 11 characters (assuming a fairly basic XOR encryption). This would include "Hello Frank", "Big fat gun" and so on.
Furthermore, Quantum Cryptography means I can essentially guarantee that you won't be able to listen in on the transmission channel of this OTP, so I can be sure that the pad will get to the person I'm communicating with in a secure manner.
Secondly, what is this rubbish about a 'brief look'? We all know it'd take nothing more than use of a screenshot facility to preserve the data to read back at ones leisure.
Thirdly, considering the venom with which MS is likely to chase down anyone in possession of the source code, would it not be worthwhile using a random one-time-pad to encrypt the code and have two people post, independently, the two halves without making claim to it containing MS code? Then a third party could point out that the code can be obtained by the appropriate XORing, and noone (except perhaps the third party, who is doing little more than posting a link) can be blamed, as both the first two have posted nothing more than random data?
Where would the law stand on this issue?
If so I think we'd best get a list of the most expensive lawyers around to maximise the damage!
I can see their faces now.... with Microsoft having to pay programmers working under the GPL, for having to make sure they wouldn't have to pay Microsoft!