Sorry but I've got absolutely no idea what you are talking about. What does "that's simply because the electrons follow wave trajectories" mean?
Of course the diffraction pattern is built up from an ensemble of electrons. The probability of detecting the electron at the point of detection is 1. That's precisely what "collapsing the wave function" means mathematically. We don't have a handle on what it means physically.
If we "label" the electrons as they pass through the slit then we don't get the diffraction pattern. If we erase that "label" without looking what it was then we do. Even more bizarrely, if we erase the "label" _AFTER_ the electron should have reached the target we still get the diffraction pattern but if we don't erase the label then we don't get a diffraction pattern. (Delayed Quantum Eraser) (Admittedly, to the best of my knowledge the delayed quantum eraser has only been done with correlated photons, not electrons but there's no known reason why it wouldn't work with electrons)
intersting, however, why does the probability wave collaps by the phosphor screen and not by the slits? because observation?
We don't know why the wave function collapses. That post a few days ago about playing "Schroedinger's Cat" with a virus was a tiny step towards understanding.
IIRC if you place measuring equipment by the slits you collapse the waveform there already (i.e. the electron goes through one slit or the other), this would destroy the interference pattern as well, no?
Correct. If you detect the electron going through a slit then you get a distribution on the phosphor screen consistent with electrons being emitted from the slits.
In the case of the double-slit experiment, this makes much more sense: an electron goes through one or the other slit, depending on where it happens to be in its wave trajectory. The apparent interference pattern on the phosphor screen is simply the result of many electrons having their own initial wave trajectories. The pictures are identical, but one is conceivable (ie, conceptual), while the other is not.
I'm not sure what you're trying to say here and I might be misinterpreting but it's explicitly not many electrons. You can turn down the beam current in the two slit experiment until you're talking about orders of magnitude less than one electron in the apparatus at any one time on average and you still get the diffraction pattern.
I've skimmed http://plato.stanford.edu/entries/qm-bohm/ and it seems to say that you've got non-local hidden variables instead. I don't know why it's any more conceptually obvious that a "variable" should be smeared out than an "electron" should be smeared out. I'll just define the electron as my variable and we're talking about the same thing (no, I still don't know what it _means_, I can just churn the numbers and get some results that agree with experiment)
No it doesn't because my post explicitly says that the wave function is a mathematical curiosity.
My post does constantly confuse an electron with the probability function of finding it. But that's because that's the way electrons behave. If anything the probability function is more fundamental so it should be "You constantly confuse the probability function with a hypothetical billiard ball model of the electron"
The wave function is a mathematical trick that just happens to allow us to calculate the probability distributions we observe. It has no known physical significance whatsoever.
It's wrong to think of the electron as a particle when it's "orbiting" in an atom. Instead you should think of it as a probability density. This is Schroedinger's cat all over again, the electron is "smeared out" all over its "orbit" but instead of being "half dead, half alive" it's x% here, y% there.
This is also like the two slit experiment. The electron doesn't go through one slit or the other, it goes through both slits (not 50% dead and 50% alive; 50% went through that slit and 50% went through this slit) but when it hits the phosphor screen it's a particle as its "where is it" probability function collapses to a point.
The "wavefunction" is (as far as we can tell) a mathematical curiosity that when squared gives us the observed probability function. The probability distribution is real, the wavefunction gives us a convenient handle to calculate probabilities and how they evolve.
But now that I've said that the wavefunction is an imaginary curiosity, imagine a sine wave on a string and then join the two ends of the string together. There will only be a few discrete lengths of string where the sine wave will "join up" correctly (ok there's an infinite number but the length of the string is limited). It turns out that, with rather a lot of unpleasant maths (see the wikipedia page for spherical harmonics), our wavefunction works like that sine wave and we find that there are only certain orbitals where the wavefunction is well behaved.
There is a point in doing Schroedinger's experiment in that we don't know if there is a level of complexity above which a superposition cannot form.
It seems crazy that a cat (or a person) can be in a state where an outside observer thinks that they must be in a mixture of dead and alive. Which would imply that at some level QM must break down.
But we do not know what that level is (or even if it exists)
Note that you don't actually have to do the dead/alive experiment. It is sufficient to have the cat (or the person) in a superposition of position in order to do the test. The dead/alive test is merely an extreme case of superposition that is hardest to "just accept that's the way the universe works."
It seems intuitively obvious that a cat will know if it is dead or alive at any point in time. However it is _theoretically_ possible to design an experiment where the cat (to an external observer) must be in a superposition of being dead and being alive unless quantum mechanics breaks down at that scale.
One question that Schroedinger's Cat raises is "Is there a level of complexity that prevents a superposition forming?" and the proposed experiment will extend the upper limit of complexity that we know quantum mechanics applies to.
Silly Europeans always have such a skewed sense of geography. Newark to Tampa is 1,000 miles, exactly. It's a two and a half hour flight and a 20 hour train ride.
That doesn't sound right. That sounds like a local train service not an intercity one.
I regularly do journeys by train: 17 miles commuter service - 17 to 22 minutes depending on whether it's non stop, one extra stop or two extra stops. 250 miles intercity service - 2h50m to 3h15
St Pancras (London) to Marseille is reported as 6h15 mins including crossing Paris. I'm not sure of the exact distance but it's getting on for 1000 miles (probably nearer 800). I've never actually done this journey although I have done Waterloo - Nimes and it's infinitely preferable to taking a plane. By the time you've done the two hours in the airport thing, the journey to and from the airport at each end etc it's not even significantly slower than taking the train.
When we create protons and antiprotons, or electrons and positrons in an accelerator we always create them in equal numbers.
The universe is (conjectured to be) uncharged. So there are equal numbers of positive and negative charges.
But we still have the idea of an isolated charge and, if we get close enough to it we can see that the divergence of the electric field is non-zero. With electrostatics it's trivial to get a macroscopic volume where the divergence is non-zero.
These papers claim the same has been achieved with magnetism. In a box approximately 1nm on a side there is a north pole with no matching south pole. So there are magnetic field lines flowing out of the box with no matching field lines flowing in. Of course "over there" there is a south pole which has field lines flowing in without field lines flowing out.
I don't see why monopoles should imply perpetual motion.
But the machine in the link you give doesn't make any sense at all. We could build it today, using electric charge instead of magnetic charge but it still won't work. Monopoles aren't some magic that mean the other laws of physics don't apply any more.
At the very least to be plausible, any perpetual motion machine that depended on magnetic monopoles would also have to depend on electric monopoles otherwise you can build an equivalent machine using electric monopoles instead of magnetic monopoles.
The universe is uncharged. Therefore every electric charge forms part of a dipole therefore electric charges aren't monopoles?
Now I've scanned one of the papers I see that they're not detecting the sort of magnetic monopole I was thinking of (i.e. a new sub-atomic particle)
Instead they've detected the equivalent of a charged molecule.
They give an analogy of the disassociation of water into H3O+ and OH-. They claim to have done the same thing with magnets - ending up with a disassociated north and south pole.
So their work doesn't appear to give any clue to the mass of a magnetic monopole particle. But AFAICT they have still created a type of magnetic monopole, exactly the same way as a proton is an electric monopole even though it has an internal structure.
A magnetic monopole is to a magnetic field what an electron is to an electric field.
This will, amongst other things, mean that Maxwell's equations become more symmetrical.
div D = rho; div B = 0
Will become
div D = rho_e; div B = rho_m
And there will be a magnetic current term for curl H.
It's long been known that if a magnetic monopole exists then charge must be quantized.
I've not looked at any of the papers but I'm interested to find out if they've got a mass estimate for them. Last I remember reading about this they were expected to be heavy (uranium nucleus sort of heavy) but I don't recall if that was an extrapolation from their non-detection or whether there was a more fundamental reason for them needing to be so massive.
Look up quantum error correction for multiple particles involved with "spooky action at a distance." Shor's paper isn't particularly hard to follow although I wouldn't have understood the notation until the final year of an undergraduate physics degree.
If you want a very gentle[1] introduction to Bell's inequality then look up Alastair Rae "Quantum Mechanics". IIRC it's the final chapter called "Conceptual problems with quantum mechanics". (The rest of the book is good too IMO)
Tim.
[1] "Very gentle" means enough maths to explain what is going on but nothing more. I'm pretty sure I'd covered all the maths needed for this chapter by A'level[2] (including further maths)
[2] A'levels are taken in the UK at 18 years of age immediately before starting a university undergraduate degree
Bells inequality rules out every possibility of the case:
result_of_experiment = me.some_function();
where some_function() has access to the entire history of me plus as much additional local information as you like (including internal variables) and it is deterministic.
There is a tiny "loophole" in that a truly rigourous test is extremely hard to do and not everybody agrees that the experiments done so far are 100% watertight.
There are only a few use cases where single user distributed and centralized revision control systems differ.
1. You can carry a local repository on your laptop and commit. You do not then need to sync to the master repository before continuing work there. (Typically in a distributed system there is one repository that is given the status of master - this avoids issues where two teams might be syncing amongst themselves but both are blissfully unaware that there is any other work happening in the same area of code.)
2. You can work simultaneously on two separate checkouts and commit them without having to "promote" one of them to a branch.
IMO any RCS that doesn't allow you to commit your tested and working snapshot whenever you want is fundamentally broken. Distributed systems must support this by definition[1] and any non distributed system that supports this can trivially be made distributed.
[1] Some distributed systems require you to merge when you synchronize changes. IMO merging should be separate from synchronizing
I can play and talk. I can't sightread and talk (I can't sightread particularly well anyway but I've been working on it over the last year and maybe I'll get there one day)
(I can (and do) practice Hanon for hours while reading a book although typically one hand at a time as that makes holding the book and turning pages easier - I've now got a Sony PRS-505 and I wish there was a remote page turn switch so I could turn the pages with my foot.)
I can copy type (poorly) and talk at the same time. Good secretaries can do this effortlessly (and usually do it all the time IME)
Simultaneous translators can (obviously) listen in one language and repeat it in another. OTOH I know people who are completely fluent in four or more languages who struggle to translate at all - they say "If you're talking French then you think in French, if you're talking English then you think in English". (I also know someone who's wife was able to act as a translator in a technical discussion between a Russian and an English speaker without being able to understand what the discussion was about - not simultaneous translation in this case so not multitasking)
I cannot read and listen to speech at the same time at all. I've previously read that this is a very rare skill in men but not that uncommon in women (Unfortunately I cannot find anything relevant when googling so I might be misremembering something else). I can't really even read and listen to music at the same time. I'll either start to switch out the music or I'll stop reading so I can listen properly.
Adjusted for population they look very similar to me.
The fact is that the NHS will treat every and all premature birth. It will also treat every and all pregnant mothers (unless you elect to pay to go privately) If there is skewing of the statistics due to infant mortality I'd think it was the other way with babies not being taken to hospital in the US until it is too late.
Every possible pattern, interesting or not, occurs in the digits of Pi because they go on forever and do not repeat
Your conclusion does not follow from your premise.
Liouville's constant is trancendental. It goes on forever, it does not repeat, and it consists almost entirely of zeros with an occasional 1 and no other digits at all.
Still not sure why you need 1m resolution to show what looks like a half mile (805 meters) or more of ice melt. Even with 15m that's 54 pixels or 3/4" inch on a 72dpi monitor. That's seems fairly visible to me. Then again maybe I'm missing something.
The 2007 melt was WAY beyond anything expected. 2008 melt stayed way below trend. There's some (slight) possibility that the 2009 melt might actually pass the 2007 minimum.
This is unexpected. Climatologists expect the polar caps to melt, Arctic going first, WAIS and Greenland later and EAIS some centuries later again. But the Arctic ocean shouldn't be melting this fast.
So now they'd like to know how and why they misjudged the severity of the polar melt. What might they be missing elsewhere?
These photos allow them to see small puddles on the surface of the ice. Puddles that affect the albedo and local heating.
Scientists will be studying these photos for years to try to explain the 2007 melt. That will then go into improving their models for future climate change.
Okay, that I don't understand at all, perhaps somebody can explain this to me, because I think I'm honestly missing something here. As far as I can tell, this whole "cow emission" thing is total bullshit. Cows' farts don't release new CO2 into the atmosphere. They release CO2 that was previously bound by the plants the cows ate, don't they? So it's all just part of the cycle of life. The real problem isn't the CO2 that was bound by plants during the last few decades and is now released again. The real problem is the CO2 that was bound millions of years ago and is now being released again, destabilizing the climate mankind has enjoyed recently.
Cows release methane. IIRC it's about 20x more potent as a greenhouse gas than CO2.
However, methane oxidizes to CO2+H2O in a fairly short time so it's not so critical when looking at long term climate change unless there is a continuous source.
After a fairly long period of constant CH4 concentration in the atmosphere, it has recently started rising again. It's not certain why that is happening. Worst case is likely to be CH4 release due to melting of permafrost and clathrates because that may indicate that we've succeeded in tipping the climate far enough that future increased warming is self sustaining even without mans input. Best case is that it's a natural effect unrelated to climate change and we've still got time to deal with global warming before it becomes too expensive (although I don't hold out any hope that we actually will deal with it proactively)
Hmmm. I've just not upgraded to firefox3 and I've no intention of doing so.
Two huge security bugs;-)
1. Puts up incorrect security warnings when websites are using self signed certificates. There is encryption and authentication. The website is using self signed SSL for encryption and user login for authentication. The website is doing everything right. Expecting the website to drop SSL and go to plain HTTP is broken.
2. That huge green blob on "secure" sites in the address bar so that you can no longer see the url that you are actually connecting to. Perhaps it works for people who have screens 13 feet wide but I like narrow windows - it makes things easier to read when your eyes don't have to scan back so far when going to the next line.
The problem with your definition of agnosticism is that 100% of people, with no margin of error at all[1], are 100% agnostic.
There are a countable number of things we can believe in.
There are an uncountably infinite number of things we have "faith" do not exist. In fact, there are an uncountably infinite number of invisible pink leprechauns of various heights that do not exist. And that's just one particular shade of pink of a leprechaun with a particularly friendly grin.
My definition of "does not exist" is that it has no measurable influence on the universe that I inhabit. God(s) do not exist. The invisible pink leprechaun that is three nanometres tall doesn't exist either. Apart from anything else, how can it be pink if it's invisible and how can something that is only three nanometres in size have a colour anyway? I am an atheist because I am a skeptic (although global warming deniers who are amongst the least skeptical people on the planet have rather hijacked that term).
Tim.
[1] I'm sure someone is going to now point out some brain damaged individual who believes absolutely everything.
int *data=myFunc(); val=*data; printf("%d\n",val); val=*data;// The compiler is allowed to optimize this call out. printf("%d\n",val);
Actually, the compiler isn't allowed to optimize that second assignment to val out unless it can see the source for printf and can prove that there are not other aliases to the memory that data points to that might be changing it.
Even if you assume the default printf(), myFunc might be returning a pointer to one of the buffers used for IO.
This is one of the reasons that C99 introduced the __restrict keyword; to allow the compiler the make the sort of optimization you are suggesting here.
but if you write kids off early and treat them as though they're useless criminals, then don't be surprised when they grow up to be useless criminals.
It's worse than that. They might start of as useless criminals, but if they're going to go into a life of crime, three years at university^Wprison is about the best education they can get.
Slashdot Mirror
Sorry but I've got absolutely no idea what you are talking about. What does "that's simply because the electrons follow wave trajectories" mean?
Of course the diffraction pattern is built up from an ensemble of electrons. The probability of detecting the electron at the point of detection is 1. That's precisely what "collapsing the wave function" means mathematically. We don't have a handle on what it means physically.
If we "label" the electrons as they pass through the slit then we don't get the diffraction pattern. If we erase that "label" without looking what it was then we do. Even more bizarrely, if we erase the "label" _AFTER_ the electron should have reached the target we still get the diffraction pattern but if we don't erase the label then we don't get a diffraction pattern. (Delayed Quantum Eraser) (Admittedly, to the best of my knowledge the delayed quantum eraser has only been done with correlated photons, not electrons but there's no known reason why it wouldn't work with electrons)
Tim.
Try reading up on Quantum Eraser.
intersting, however, why does the probability wave collaps by the phosphor screen and not by the slits? because observation?
We don't know why the wave function collapses. That post a few days ago about playing "Schroedinger's Cat" with a virus was a tiny step towards understanding.
IIRC if you place measuring equipment by the slits you collapse the waveform there already (i.e. the electron goes through one slit or the other), this would destroy the interference pattern as well, no?
Correct. If you detect the electron going through a slit then you get a distribution on the phosphor screen consistent with electrons being emitted from the slits.
Tim.
In the case of the double-slit experiment, this makes much more sense: an electron goes through one or the other slit, depending on where it happens to be in its wave trajectory. The apparent interference pattern on the phosphor screen is simply the result of many electrons having their own initial wave trajectories. The pictures are identical, but one is conceivable (ie, conceptual), while the other is not.
I'm not sure what you're trying to say here and I might be misinterpreting but it's explicitly not many electrons. You can turn down the beam current in the two slit experiment until you're talking about orders of magnitude less than one electron in the apparatus at any one time on average and you still get the diffraction pattern.
I've skimmed http://plato.stanford.edu/entries/qm-bohm/ and it seems to say that you've got non-local hidden variables instead. I don't know why it's any more conceptually obvious that a "variable" should be smeared out than an "electron" should be smeared out. I'll just define the electron as my variable and we're talking about the same thing (no, I still don't know what it _means_, I can just churn the numbers and get some results that agree with experiment)
Tim.
No it doesn't because my post explicitly says that the wave function is a mathematical curiosity.
My post does constantly confuse an electron with the probability function of finding it. But that's because that's the way electrons behave. If anything the probability function is more fundamental so it should be "You constantly confuse the probability function with a hypothetical billiard ball model of the electron"
The wave function is a mathematical trick that just happens to allow us to calculate the probability distributions we observe. It has no known physical significance whatsoever.
Tim.
It's wrong to think of the electron as a particle when it's "orbiting" in an atom. Instead you should think of it as a probability density. This is Schroedinger's cat all over again, the electron is "smeared out" all over its "orbit" but instead of being "half dead, half alive" it's x% here, y% there.
This is also like the two slit experiment. The electron doesn't go through one slit or the other, it goes through both slits (not 50% dead and 50% alive; 50% went through that slit and 50% went through this slit) but when it hits the phosphor screen it's a particle as its "where is it" probability function collapses to a point.
The "wavefunction" is (as far as we can tell) a mathematical curiosity that when squared gives us the observed probability function. The probability distribution is real, the wavefunction gives us a convenient handle to calculate probabilities and how they evolve.
But now that I've said that the wavefunction is an imaginary curiosity, imagine a sine wave on a string and then join the two ends of the string together. There will only be a few discrete lengths of string where the sine wave will "join up" correctly (ok there's an infinite number but the length of the string is limited). It turns out that, with rather a lot of unpleasant maths (see the wikipedia page for spherical harmonics), our wavefunction works like that sine wave and we find that there are only certain orbitals where the wavefunction is well behaved.
Tim.
There is a point in doing Schroedinger's experiment in that we don't know if there is a level of complexity above which a superposition cannot form.
It seems crazy that a cat (or a person) can be in a state where an outside observer thinks that they must be in a mixture of dead and alive. Which would imply that at some level QM must break down.
But we do not know what that level is (or even if it exists)
Note that you don't actually have to do the dead/alive experiment. It is sufficient to have the cat (or the person) in a superposition of position in order to do the test. The dead/alive test is merely an extreme case of superposition that is hardest to "just accept that's the way the universe works."
Tim.
It seems intuitively obvious that a cat will know if it is dead or alive at any point in time. However it is _theoretically_ possible to design an experiment where the cat (to an external observer) must be in a superposition of being dead and being alive unless quantum mechanics breaks down at that scale.
One question that Schroedinger's Cat raises is "Is there a level of complexity that prevents a superposition forming?" and the proposed experiment will extend the upper limit of complexity that we know quantum mechanics applies to.
Tim.
Silly Europeans always have such a skewed sense of geography. Newark to Tampa is 1,000 miles, exactly. It's a two and a half hour flight and a 20 hour train ride.
That doesn't sound right. That sounds like a local train service not an intercity one.
I regularly do journeys by train:
17 miles commuter service - 17 to 22 minutes depending on whether it's non stop, one extra stop or two extra stops.
250 miles intercity service - 2h50m to 3h15
St Pancras (London) to Marseille is reported as 6h15 mins including crossing Paris. I'm not sure of the exact distance but it's getting on for 1000 miles (probably nearer 800). I've never actually done this journey although I have done Waterloo - Nimes and it's infinitely preferable to taking a plane. By the time you've done the two hours in the airport thing, the journey to and from the airport at each end etc it's not even significantly slower than taking the train.
Tim.
When we create protons and antiprotons, or electrons and positrons in an accelerator we always create them in equal numbers.
The universe is (conjectured to be) uncharged. So there are equal numbers of positive and negative charges.
But we still have the idea of an isolated charge and, if we get close enough to it we can see that the divergence of the electric field is non-zero. With electrostatics it's trivial to get a macroscopic volume where the divergence is non-zero.
These papers claim the same has been achieved with magnetism. In a box approximately 1nm on a side there is a north pole with no matching south pole. So there are magnetic field lines flowing out of the box with no matching field lines flowing in. Of course "over there" there is a south pole which has field lines flowing in without field lines flowing out.
Tim.
I don't see why monopoles should imply perpetual motion.
But the machine in the link you give doesn't make any sense at all. We could build it today, using electric charge instead of magnetic charge but it still won't work. Monopoles aren't some magic that mean the other laws of physics don't apply any more.
At the very least to be plausible, any perpetual motion machine that depended on magnetic monopoles would also have to depend on electric monopoles otherwise you can build an equivalent machine using electric monopoles instead of magnetic monopoles.
The universe is uncharged. Therefore every electric charge forms part of a dipole therefore electric charges aren't monopoles?
Tim.
Now I've scanned one of the papers I see that they're not detecting the sort of magnetic monopole I was thinking of (i.e. a new sub-atomic particle)
Instead they've detected the equivalent of a charged molecule.
They give an analogy of the disassociation of water into H3O+ and OH-. They claim to have done the same thing with magnets - ending up with a disassociated north and south pole.
So their work doesn't appear to give any clue to the mass of a magnetic monopole particle. But AFAICT they have still created a type of magnetic monopole, exactly the same way as a proton is an electric monopole even though it has an internal structure.
Tim.
A magnetic monopole is to a magnetic field what an electron is to an electric field.
This will, amongst other things, mean that Maxwell's equations become more symmetrical.
div D = rho; div B = 0
Will become
div D = rho_e; div B = rho_m
And there will be a magnetic current term for curl H.
It's long been known that if a magnetic monopole exists then charge must be quantized.
I've not looked at any of the papers but I'm interested to find out if they've got a mass estimate for them. Last I remember reading about this they were expected to be heavy (uranium nucleus sort of heavy) but I don't recall if that was an extrapolation from their non-detection or whether there was a more fundamental reason for them needing to be so massive.
Tim.
Look up quantum error correction for multiple particles involved with "spooky action at a distance." Shor's paper isn't particularly hard to follow although I wouldn't have understood the notation until the final year of an undergraduate physics degree.
If you want a very gentle[1] introduction to Bell's inequality then look up Alastair Rae "Quantum Mechanics". IIRC it's the final chapter called "Conceptual problems with quantum mechanics". (The rest of the book is good too IMO)
Tim.
[1] "Very gentle" means enough maths to explain what is going on but nothing more. I'm pretty sure I'd covered all the maths needed for this chapter by A'level[2] (including further maths)
[2] A'levels are taken in the UK at 18 years of age immediately before starting a university undergraduate degree
Bells inequality rules out every possibility of the case:
result_of_experiment = me.some_function();
where some_function() has access to the entire history of me plus as much additional local information as you like (including internal variables) and it is deterministic.
There is a tiny "loophole" in that a truly rigourous test is extremely hard to do and not everybody agrees that the experiments done so far are 100% watertight.
Tim.
There are only a few use cases where single user distributed and centralized revision control systems differ.
1. You can carry a local repository on your laptop and commit. You do not then need to sync to the master repository before continuing work there. (Typically in a distributed system there is one repository that is given the status of master - this avoids issues where two teams might be syncing amongst themselves but both are blissfully unaware that there is any other work happening in the same area of code.)
2. You can work simultaneously on two separate checkouts and commit them without having to "promote" one of them to a branch.
IMO any RCS that doesn't allow you to commit your tested and working snapshot whenever you want is fundamentally broken. Distributed systems must support this by definition[1] and any non distributed system that supports this can trivially be made distributed.
[1] Some distributed systems require you to merge when you synchronize changes. IMO merging should be separate from synchronizing
Tim.
I can play and talk. I can't sightread and talk (I can't sightread particularly well anyway but I've been working on it over the last year and maybe I'll get there one day)
(I can (and do) practice Hanon for hours while reading a book although typically one hand at a time as that makes holding the book and turning pages easier - I've now got a Sony PRS-505 and I wish there was a remote page turn switch so I could turn the pages with my foot.)
I can copy type (poorly) and talk at the same time. Good secretaries can do this effortlessly (and usually do it all the time IME)
Simultaneous translators can (obviously) listen in one language and repeat it in another. OTOH I know people who are completely fluent in four or more languages who struggle to translate at all - they say "If you're talking French then you think in French, if you're talking English then you think in English". (I also know someone who's wife was able to act as a translator in a technical discussion between a Russian and an English speaker without being able to understand what the discussion was about - not simultaneous translation in this case so not multitasking)
I cannot read and listen to speech at the same time at all. I've previously read that this is a very rare skill in men but not that uncommon in women (Unfortunately I cannot find anything relevant when googling so I might be misremembering something else). I can't really even read and listen to music at the same time. I'll either start to switch out the music or I'll stop reading so I can listen properly.
Tim.
I don't know why you would think that Europe won't intervene.
http://www.telegraph.co.uk/health/healthnews/4420446/Premature-births-cost-the-NHS-almost-1-billion-a-year.html
80000 premature births in the UK
http://www.nlm.nih.gov/medlineplus/prematurebabies.html
480000 premature births in the US.
Adjusted for population they look very similar to me.
The fact is that the NHS will treat every and all premature birth. It will also treat every and all pregnant mothers (unless you elect to pay to go privately) If there is skewing of the statistics due to infant mortality I'd think it was the other way with babies not being taken to hospital in the US until it is too late.
Tim.
Every possible pattern, interesting or not, occurs in the digits of Pi because they go on forever and do not repeat
Your conclusion does not follow from your premise.
Liouville's constant is trancendental. It goes on forever, it does not repeat, and it consists almost entirely of zeros with an occasional 1 and no other digits at all.
http://en.wikipedia.org/wiki/Liouville_number#Liouville_constant
Tim.
Still not sure why you need 1m resolution to show what looks like a half mile (805 meters) or more of ice melt.
Even with 15m that's 54 pixels or 3/4" inch on a 72dpi monitor. That's seems fairly visible to me.
Then again maybe I'm missing something.
The 2007 melt was WAY beyond anything expected. 2008 melt stayed way below trend. There's some (slight) possibility that the 2009 melt might actually pass the 2007 minimum.
This is unexpected. Climatologists expect the polar caps to melt, Arctic going first, WAIS and Greenland later and EAIS some centuries later again. But the Arctic ocean shouldn't be melting this fast.
So now they'd like to know how and why they misjudged the severity of the polar melt. What might they be missing elsewhere?
These photos allow them to see small puddles on the surface of the ice. Puddles that affect the albedo and local heating.
Scientists will be studying these photos for years to try to explain the 2007 melt. That will then go into improving their models for future climate change.
Tim.
Okay, that I don't understand at all, perhaps somebody can explain this to me, because I think I'm honestly missing something here. As far as I can tell, this whole "cow emission" thing is total bullshit. Cows' farts don't release new CO2 into the atmosphere. They release CO2 that was previously bound by the plants the cows ate, don't they? So it's all just part of the cycle of life. The real problem isn't the CO2 that was bound by plants during the last few decades and is now released again. The real problem is the CO2 that was bound millions of years ago and is now being released again, destabilizing the climate mankind has enjoyed recently.
Cows release methane. IIRC it's about 20x more potent as a greenhouse gas than CO2.
However, methane oxidizes to CO2+H2O in a fairly short time so it's not so critical when looking at long term climate change unless there is a continuous source.
After a fairly long period of constant CH4 concentration in the atmosphere, it has recently started rising again. It's not certain why that is happening. Worst case is likely to be CH4 release due to melting of permafrost and clathrates because that may indicate that we've succeeded in tipping the climate far enough that future increased warming is self sustaining even without mans input. Best case is that it's a natural effect unrelated to climate change and we've still got time to deal with global warming before it becomes too expensive (although I don't hold out any hope that we actually will deal with it proactively)
Tim.
Hmmm. I've just not upgraded to firefox3 and I've no intention of doing so.
Two huge security bugs ;-)
1. Puts up incorrect security warnings when websites are using self signed certificates. There is encryption and authentication. The website is using self signed SSL for encryption and user login for authentication. The website is doing everything right. Expecting the website to drop SSL and go to plain HTTP is broken.
2. That huge green blob on "secure" sites in the address bar so that you can no longer see the url that you are actually connecting to. Perhaps it works for people who have screens 13 feet wide but I like narrow windows - it makes things easier to read when your eyes don't have to scan back so far when going to the next line.
Tim.
The problem with your definition of agnosticism is that 100% of people, with no margin of error at all[1], are 100% agnostic.
There are a countable number of things we can believe in.
There are an uncountably infinite number of things we have "faith" do not exist. In fact, there are an uncountably infinite number of invisible pink leprechauns of various heights that do not exist. And that's just one particular shade of pink of a leprechaun with a particularly friendly grin.
My definition of "does not exist" is that it has no measurable influence on the universe that I inhabit. God(s) do not exist. The invisible pink leprechaun that is three nanometres tall doesn't exist either. Apart from anything else, how can it be pink if it's invisible and how can something that is only three nanometres in size have a colour anyway? I am an atheist because I am a skeptic (although global warming deniers who are amongst the least skeptical people on the planet have rather hijacked that term).
Tim.
[1] I'm sure someone is going to now point out some brain damaged individual who believes absolutely everything.
int *data=myFunc();
val=*data;
printf("%d\n",val);
val=*data;
printf("%d\n",val);
Actually, the compiler isn't allowed to optimize that second assignment to val out unless it can see the source for printf and can prove that there are not other aliases to the memory that data points to that might be changing it.
Even if you assume the default printf(), myFunc might be returning a pointer to one of the buffers used for IO.
This is one of the reasons that C99 introduced the __restrict keyword; to allow the compiler the make the sort of optimization you are suggesting here.
Tim.
but if you write kids off early and treat them as though they're useless criminals, then don't be surprised when they grow up to be useless criminals.
It's worse than that. They might start of as useless criminals, but if they're going to go into a life of crime, three years at university^Wprison is about the best education they can get.
Tim.