Since noone in this thread seems to have understood the issue, here's what I gathered after reading some German-language newspapers (I've not used google news in years, so please point out inaccuracies kindly):
So far, everytime you clicked on a story on google news, it took you to an article somewhere else. I.e., everytime there was an interesting story on google news, somebody else would share the profit.
But now google starts running news agency stories themselves. I.e., whenever someone clicks on an AP, say, story, they are redirected to a google news page that carries the AP story. Previously, it would have been some newspaper's page who happened to run that story.
So far so good. But how does google news decide which agency stories to place on their front page? For that, they use the story placement on the various news sites they're aggregating, and this is where it becomes unfair because this work is an essential part of running a news web site -- unordered newsfeeds aren't worth much, as otherwise everybody would be getting their news from ap.org or whatever.
In other words, by running stories from news agencies themselves, google has turned from someone benefitting the various news sites into a freeloader.
log(1000) / log(10) gives 2.99999999999999956 in double precision, i.e. google probably doesn't use the decadic log function (i.e. log10) in its implementation, but the natural logarithm instead.
This wouldn't have happened 1) if the guy hadn't had access to inordinate amounts of bullets (you can't kill 15 people with less than 15 bullets) 2) if the guy hadn't had access to a gun that was stored outside the legally required locked safe 3) if the guy hadn't been given weapons training even though his diagnosed mental condition (again, this was against the law)
Once you've addressed these issues, we may want to talk about banning violent games.
Because RNAD Coulton (which is about 4 miles west of the linked site) is hidden under a cloud, I guess. Damned publicity whores, wanted their whole base on google maps but only got half of it exposed.
Unwanted to whom? Not all geeks care that much about privacy. There may be a loud portion that's always talking about PGP and privacy plugins for pidgin, including a (much smaller) contingent that hides away from cameras in real life and tries to obscure their features there. There's also a fair set of just-as-clued-and-geeky folk who are resigned to privacy being not worth the pain, as well as those who value radical openness and push for far less privacy than tradition has given humanity in the past.
Well, finally the technology is there to push your views on others. This is what we privacy-aware people see as the problem (this, and stupid people who just don't understand the implications of these kinds of services).
This formula is only valid in a particle's rest frame. A photon (= light particle) doesn't have a rest frame, as it moves at the speed of light c in every frame. The general formula for frames (moving at constant velocity yaddayadda) is
E^2 + p^2 c^2 == m^2 c^4,
which reduces to the formula you quoted for p = 0, which is of course the definition of the rest frame.
OTOH for massless particles, m = 0, it follows
E = p c,
i.e. energy and momentum are the same for a massless particle.
Now, what is the meaning of the momentum for a photon? A photon can hit an electron, losing its momentum to the electron (plus a recoil, say, nucleus, which is needed for energy-momentum-conservation, yaddayadda), and the maximum momentum it can transfer to the electron is the momentum of the photon.
There are two things to note:
- the momentum p of a photon is related to its frequency f by p = 2 pi f h (h Planck's constant), and
- since momentum changes under Lorentz tranformation, the frequency of light does likewise (think "red-shift" [neglecting gracitational shifts yaddayadda])
Hope this cleared some misconceptions.
whygitisbettertanx.com claims that mercurial doesn't have cheap branching -- the only advantage he sees git having over hg if leaving aside github. I'm surprised by this statement because I use hg branches everyday. The things he describes can all be done straightforwardly with hg, so I'm asking: can anybody in the know tell me if and how git branches are in any way more powerful than hg branches?
FTR I love hg, and I see no reason to switch to git, even though the whole bandwagon movement seems to have jumped on the git train.
Never limit your regexp to a specific length if looking for the longest word:) $ grep "^[qwertasdfgzxcvb]\{14,\}"/usr/share/dict/words
tessarescaedecahedron
$
"[It] is designed to make Mathematica as invaluable for scientific research as it is for mathematics."
Cut down the advertising please. Or at least advertize some free software.
It's been a while since I needes a computer algebra system. How are the free alternatives coming along? Any recommendations?
To add to thr previous:
Arnold's book on mechanics is probably the best you can get as a mathematician. Very clear on the physics, explaining how to make conclusions about physics from intuition, but at the same time exposing the mathematics in a rigid fashion.
It mostly deals with point mechanics, though, so there are not really many PDEs.
If you look at http://en.wikipedia.org/wiki/Knuth_reward_check you'll see a picture of a check with all the numbers. A Yahoo-image search immediately yields scanned checks, both front and back. More attack vectors, indeed.
So you're the guy who develops web pages in Firefox but never bothers to see what they look like in IE â" until his boss complains months later that the company website looks like shit. I call BS.
The gravitational attraction between bodies must also be considered: it is negligible between individual particles, but comes into effect for macroscopic objects. The gravitational interaction is determined by the amount of mass present, and is always attractive, regardless of whether it is between matter or antimatter.
This is an unproven assertion. Noone ever built a large enough lump of antimatter to verify that its gravitational force is indeed attractive. It is true that within the current physical theories gravity is always attractive (leaving aside the cosmological terms), yet, unless this is verified by experiment it is but a very convincing assumption.
This is a cool hack. From what it looks like, this is possible because DOS put the boot sector and the root directory in the beginning of the disk, whereas the C64 made the sane choice of putting it in the middle (think about it, this minimizes seek times). Now the directory (or, more precisely, the File Allocation Table (=FAT)) contains information on so-called bad blocks, i.e. blocks that the OS shouldn't write to because they were known to be bad. If you label the blocks that you put the C64 data into as bad blocks, then DOS is not going to overwrite the C64 data. Now you do the same in the C64 FS and bang -- double OS format created. And it's read/write!
I wonder if someone managed to format a disk such that one was also able to share the data space between the different OSs?
The webcam is a great source of information on CMS:), but if you want to know the status of the LHC, check the following links:
The current status of the beam can always be viewed here
All other status informations are linked from here
So maybe they didn't make a press release, but perhaps journalists should be smart enough to find these pages instead of claiming conspiracies?
See subject, all this talk about checking if keys could be affected, but how does one do that? E.g. gcc.gnu.org should be very interested in this, as all access is handled by ssh keys, and getting every gcc contributor to change their key sounds like an uphill battle, whereas forcing the few affected should be easy enough.
Not compatibility between (La)TeX versions, compatibility between different packages. Everything in TeX needs some package, and when I try to combine different stuff I invariably run into incompatibilities between different packages, so I totally agree with the submitter's sentiments that the TeX world is full of incompatibilities.
A small correction: être vs avoir as auxiliary verb is determined by the verb being reflexive or not, not by it being transitive or not. "je me suis lavé" = reflexive, "j'ai lavé mes mains" = not reflexive. There are also a few special verbs that express a movement that use tre, even though they're not reflexive (e.g. "je suis allé").ps why don't accented characters work in comments? And I thought I could delete HTML entities from my brain.
Well, I don't know why they decided the way they did. But it is clear that even if a material were desirable from a physics point of view, it might be impossible to use it, due to chemical instability, mechanical instability, cost, prohibitve security requirements during manufacturing, etc.
BTW is there any slashdot story that attracted fewer comments?
I'm currently building a detector for photons (= gamma rays) and pions in the range of ~10MeV to a ~100GeV. Our implementation is different, due to our interest in particles other than photons, but the approach is similar. The important point to realize is that you're not detecting the photons, you're detecting secondary particles created by the photons. That's why they have the Tungsten layers in GLAST (people with a smaller budget usually uses lead). Photons passing through it will undergo pair conversion, producing pairs of electrons and positron. You need a heavy material for this purpose, as the interaction probability strongly increases with the charge of the nucleus (Z^2) and its density (proportionally). These pairs are then detected in the silicon microstrip detectors, not the photons themselves.
Since these electron-positron pairs carry most of the energy of the photon (some of it is transferred to the recoiling heavy core), they will in turn radiate of gamma rays of lower energy in a process called Bremsstrahlung. These Bremsstrahlung photons will undergo pair prodution again until the end of detector or until all energy has been absorbed, whatever comes first. This process is called showering. Since GLAST is inside a space vessel it can't be large enough to contain the whole shower, and this is where the Caesium Iodide calorimeter comes in: the charged shower particles leaking out of the first part of the detector will produce light flashes whose intensity and duration which allow the GLAST people to determine the number of shower particles (and maybe rough estimates of their energy) and in turn this will allow them to estimate the energy of the original incident particle.
The constraint of low mass really works against a precise enrgy measurement, but looking at shower shapes the way GLAST does may reveal enough information to obtain halfway reliable numbers.
I'm definitely looking forward to seeing their results. Go GLAST.
Nothing in the contest description says that the remainder of the image must remain untouched, so you could e.g. distribute the contents of the blocked out region steganographically. Also, what the previous poster said: blocked out doesn't necessarily mean blacked out.
Wow, -1 Funny. You've invented anti-funny which I think that can trigger outbursts of straight-faced ness. That's quite an achievement. Is anti-funny what keeps whooshing under my feet?
Slashdot Mirror
Since noone in this thread seems to have understood the issue, here's what I gathered after reading some German-language newspapers (I've not used google news in years, so please point out inaccuracies kindly):
So far, everytime you clicked on a story on google news, it took you to an article somewhere else. I.e., everytime there was an interesting story on google news, somebody else would share the profit.
But now google starts running news agency stories themselves. I.e., whenever someone clicks on an AP, say, story, they are redirected to a google news page that carries the AP story. Previously, it would have been some newspaper's page who happened to run that story.
So far so good. But how does google news decide which agency stories to place on their front page? For that, they use the story placement on the various news sites they're aggregating, and this is where it becomes unfair because this work is an essential part of running a news web site -- unordered newsfeeds aren't worth much, as otherwise everybody would be getting their news from ap.org or whatever.
In other words, by running stories from news agencies themselves, google has turned from someone benefitting the various news sites into a freeloader.
log(1000) / log(10) gives 2.99999999999999956 in double precision, i.e. google probably doesn't use the decadic log function (i.e. log10) in its implementation, but the natural logarithm instead.
This wouldn't have happened
1) if the guy hadn't had access to inordinate amounts of bullets (you can't kill 15 people with less than 15 bullets)
2) if the guy hadn't had access to a gun that was stored outside the legally required locked safe
3) if the guy hadn't been given weapons training even though his diagnosed mental condition (again, this was against the law)
Once you've addressed these issues, we may want to talk about banning violent games.
why the hell are they outraged exactly?
Because RNAD Coulton (which is about 4 miles west of the linked site) is hidden under a cloud, I guess. Damned publicity whores, wanted their whole base on google maps but only got half of it exposed.
Unwanted to whom? Not all geeks care that much about privacy. There may be a loud portion that's always talking about PGP and privacy plugins for pidgin, including a (much smaller) contingent that hides away from cameras in real life and tries to obscure their features there. There's also a fair set of just-as-clued-and-geeky folk who are resigned to privacy being not worth the pain, as well as those who value radical openness and push for far less privacy than tradition has given humanity in the past.
Well, finally the technology is there to push your views on others. This is what we privacy-aware people see as the problem (this, and stupid people who just don't understand the implications of these kinds of services).
The first formula should have a minus sign between the first two terms, sorry.
This formula is only valid in a particle's rest frame. A photon (= light particle) doesn't have a rest frame, as it moves at the speed of light c in every frame. The general formula for frames (moving at constant velocity yaddayadda) is
E^2 + p^2 c^2 == m^2 c^4,
which reduces to the formula you quoted for p = 0, which is of course the definition of the rest frame.
OTOH for massless particles, m = 0, it follows
E = p c,
i.e. energy and momentum are the same for a massless particle.
Now, what is the meaning of the momentum for a photon? A photon can hit an electron, losing its momentum to the electron (plus a recoil, say, nucleus, which is needed for energy-momentum-conservation, yaddayadda), and the maximum momentum it can transfer to the electron is the momentum of the photon.
There are two things to note:
- the momentum p of a photon is related to its frequency f by p = 2 pi f h (h Planck's constant), and
- since momentum changes under Lorentz tranformation, the frequency of light does likewise (think "red-shift" [neglecting gracitational shifts yaddayadda])
Hope this cleared some misconceptions.
whygitisbettertanx.com claims that mercurial doesn't have cheap branching -- the only advantage he sees git having over hg if leaving aside github. I'm surprised by this statement because I use hg branches everyday. The things he describes can all be done straightforwardly with hg, so I'm asking: can anybody in the know tell me if and how git branches are in any way more powerful than hg branches?
FTR I love hg, and I see no reason to switch to git, even though the whole bandwagon movement seems to have jumped on the git train.
Never limit your regexp to a specific length if looking for the longest word :) /usr/share/dict/words
$ grep "^[qwertasdfgzxcvb]\{14,\}"
tessarescaedecahedron
$
"[It] is designed to make Mathematica as invaluable for scientific research as it is for mathematics." Cut down the advertising please. Or at least advertize some free software. It's been a while since I needes a computer algebra system. How are the free alternatives coming along? Any recommendations?
To add to thr previous: Arnold's book on mechanics is probably the best you can get as a mathematician. Very clear on the physics, explaining how to make conclusions about physics from intuition, but at the same time exposing the mathematics in a rigid fashion. It mostly deals with point mechanics, though, so there are not really many PDEs.
If you look at http://en.wikipedia.org/wiki/Knuth_reward_check you'll see a picture of a check with all the numbers. A Yahoo-image search immediately yields scanned checks, both front and back. More attack vectors, indeed.
So you're the guy who develops web pages in Firefox but never bothers to see what they look like in IE â" until his boss complains months later that the company website looks like shit. I call BS.
The gravitational attraction between bodies must also be considered: it is negligible between individual particles, but comes into effect for macroscopic objects. The gravitational interaction is determined by the amount of mass present, and is always attractive, regardless of whether it is between matter or antimatter.
This is an unproven assertion. Noone ever built a large enough lump of antimatter to verify that its gravitational force is indeed attractive. It is true that within the current physical theories gravity is always attractive (leaving aside the cosmological terms), yet, unless this is verified by experiment it is but a very convincing assumption.
This is a cool hack. From what it looks like, this is possible because DOS put the boot sector and the root directory in the beginning of the disk, whereas the C64 made the sane choice of putting it in the middle (think about it, this minimizes seek times). Now the directory (or, more precisely, the File Allocation Table (=FAT)) contains information on so-called bad blocks, i.e. blocks that the OS shouldn't write to because they were known to be bad. If you label the blocks that you put the C64 data into as bad blocks, then DOS is not going to overwrite the C64 data. Now you do the same in the C64 FS and bang -- double OS format created. And it's read/write!
I wonder if someone managed to format a disk such that one was also able to share the data space between the different OSs?
The webcam is a great source of information on CMS :), but if you want to know the status of the LHC, check the following links:
The current status of the beam can always be viewed here
All other status informations are linked from here
So maybe they didn't make a press release, but perhaps journalists should be smart enough to find these pages instead of claiming conspiracies?
Thanks for the pointer!
See subject, all this talk about checking if keys could be affected, but how does one do that? E.g. gcc.gnu.org should be very interested in this, as all access is handled by ssh keys, and getting every gcc contributor to change their key sounds like an uphill battle, whereas forcing the few affected should be easy enough.
Only leftist pinko-commie-terrists-democrats would think that human life outweighs the benefits of a Free Market.
You forgot "christian" in that list :)
Not compatibility between (La)TeX versions, compatibility between different packages. Everything in TeX needs some package, and when I try to combine different stuff I invariably run into incompatibilities between different packages, so I totally agree with the submitter's sentiments that the TeX world is full of incompatibilities.
A small correction: être vs avoir as auxiliary verb is determined by the verb being reflexive or not, not by it being transitive or not. "je me suis lavé" = reflexive, "j'ai lavé mes mains" = not reflexive. There are also a few special verbs that express a movement that use tre, even though they're not reflexive (e.g. "je suis allé").ps why don't accented characters work in comments? And I thought I could delete HTML entities from my brain.
Well, I don't know why they decided the way they did. But it is clear that even if a material were desirable from a physics point of view, it might be impossible to use it, due to chemical instability, mechanical instability, cost, prohibitve security requirements during manufacturing, etc.
BTW is there any slashdot story that attracted fewer comments?
I'm currently building a detector for photons (= gamma rays) and pions in the range of ~10MeV to a ~100GeV. Our implementation is different, due to our interest in particles other than photons, but the approach is similar. The important point to realize is that you're not detecting the photons, you're detecting secondary particles created by the photons. That's why they have the Tungsten layers in GLAST (people with a smaller budget usually uses lead). Photons passing through it will undergo pair conversion, producing pairs of electrons and positron. You need a heavy material for this purpose, as the interaction probability strongly increases with the charge of the nucleus (Z^2) and its density (proportionally). These pairs are then detected in the silicon microstrip detectors, not the photons themselves.
Since these electron-positron pairs carry most of the energy of the photon (some of it is transferred to the recoiling heavy core), they will in turn radiate of gamma rays of lower energy in a process called Bremsstrahlung. These Bremsstrahlung photons will undergo pair prodution again until the end of detector or until all energy has been absorbed, whatever comes first. This process is called showering. Since GLAST is inside a space vessel it can't be large enough to contain the whole shower, and this is where the Caesium Iodide calorimeter comes in: the charged shower particles leaking out of the first part of the detector will produce light flashes whose intensity and duration which allow the GLAST people to determine the number of shower particles (and maybe rough estimates of their energy) and in turn this will allow them to estimate the energy of the original incident particle.
The constraint of low mass really works against a precise enrgy measurement, but looking at shower shapes the way GLAST does may reveal enough information to obtain halfway reliable numbers.
I'm definitely looking forward to seeing their results. Go GLAST.
Nothing in the contest description says that the remainder of the image must remain untouched, so you could e.g. distribute the contents of the blocked out region steganographically. Also, what the previous poster said: blocked out doesn't necessarily mean blacked out.