to all editors: feel free to label this response as troll. i just get annoyed by posts which
a) have absolutely no content and are completely unfunded and
b) morons who do not know jack shit about someting.
finally, i would have expected more cojones than an anonymous post. slashdot: do us all a favor and delete comments from the anti-slashdot morons. freedom of speech? where? in the internet? ha!
i have worked a bit in the field of nano-decorated surfaces. it is impressive that one can make little nano-sizes arrays of magnetic dots on some substrate . this as so small, that one can view them as single particles which switch homogenously. hence you can study the interactions of little magnetic particles in arrays and do experiments which are very close to theoretical models, such as the Ising model. why should you care? because this nano-patterns seem to be interesting for exchange biased systems. and these seem to be interesting for the recording media industry. but why should you care... this is too geeky anyways. this guy (AKA Prof. Kai Liu) at UC Davis does some interesting research with nanostructures... cool pics and some explanations...
nice post... not just "good word of mouth". if you actively are participating in mailing lists and filing bug reports (like i used to do) then you are actually rewarding them for a product. money is not the only currency, but i guess we are the only two who think that way.... : )
i have been in contact with redhat directly about this. what they say to the media is not quite what they tell the customer: "we do not endorse RHPW and so cannot give you any info about it". as for site licenses, no official word yet...
your question makes sense and does not. if i use redhat and am happy, then i will recommend it to others, potential paying customers. if i am not happy, i will make bad publicity for them. it is a matter of the definition of "customer", but if you provide me with a service, regardless if i pay for it or not, i am your customer.
think about it: RH claims 90% of their customers are loyal because they are keeping their subscriptions. the important question is:
How many customers of RH did actually pay for a subscription before the change? And from those how did not pay (but were loyal Rh customers), how many are sticking with it?
The ones who paid before the kaboom do not care in spending bick bucks. The users who supported redhat but could not afford such a pricey OS definitely will not stick with it -- as it is the case in Academia! If RH were smart, they would offer site licenses for academia and big clusters.
I am willing to be my officemate (he is a good catch) that from the RH users who did NOT pay in the first place, 90% will switch to another OS if RH does not offer something "in-between". How about also releasing this information, RH?
(As one always learns in statistics: the outcome depends on HOW you present the data, and not what it actually looks like...)
i have been using spamassassin for a year and it works great! granted, in the beginnings about 18% of the spam (in my case 18% of about 30 emails per day) would get trough. BUT if you read the manpage and tweak with the different scores a bit, you can get that down to 1 - 2% with about the same amount of false positives. as an admin, you should be able to tweak any spam filter to match your needs best.
what i can highly recommend is to increase the score of MICROSOFT_EXECUTABLE as it generally is a piece of spam. in addition the bayesian statistics are a great idea: a spam filter that learns!
as for the reviewer: if it takes this person 10 times longer to read a manpage and punch in some trivial scores into a trivially set up configuration file, then you should take his review with a HUGE grain of salt... especially since he reviewed an ancient version of the software.
finally a general comment about spamassassin: EXCELLENT software, especially for the bargain price of $0.
yet again it seems that academia bites the dust. redhat seems to have moved over to corporate servers, yet they do not want to offer a "service-less" product for academia. we do not need service from redhat, we need a GOOD and STABLE OS for a REASONABLE price -- and updates, of course.
So please, RH, think over your policies. Academia is a big market and we like redhat, so do not take us away from you.
As a side note: I called RH UK last week Thursday. I am still waiting for the promised email from Mrs. Alonso regading my questions about RH Professional Workstation, which seems to be the answer academia is waiting for. All I need to know is if RH is willing to sell their RHEL WS software with access to up2date for a reasonable price and what the licensing conditions are. Can we buy more RHN subscriptons and get just one package???
did you notice the palm 515 review as part of a "headline"? that thing has been out for years!!! there are two pics below... i wonder how they choose their stories, but as far as i am concerned, i will swtick to google news for the time...
There are many long-time users of RH linux, such as myself, who over the years have relied on your company for mission critical applications of the OS (in my case my research as well as the computational clusters I use). Suddenly RH pushes their enterprise products and drops free software COMPLETELY. I have tested Fedora Linux and I do not think it is mature enough to run on mission critical applications. Clearly there are two options:
a) Pay for the yearly (!) $180+ license or...
b) Stop using RH Linux.
In my case, this will mean turning my back to RH and what I have heard from others, they intend to do the same. The corporate customers, who follow suggestions from their system administrators and who pay for a license, will probably follow in these footsteps because RH is becoming more and more corporate. Don't you think you basically started the end of RH with this move?
On the other hand I do not understand why I ask you this question: I already know your answer; "we do not make money with RH Linux and so we drop it and focus on Enterprise RH Linux". The problem is that most do not need help from RH to manage their systems -- unless they hire a windows sysadmin, and so, as I wrote above, your days are counted.
Having an experimental setup that no-one else in the world has is certainly a one way of getting a Nature of Science paper. However, to say that it's easier is quite an overstatement - unless you think it's easy to get funding for a prototype system costing several millions of USD.
As a theorist I *have* done experiments next to my analytical and computational work. And let me tell you: running a Quantum Design Magnetometer or a Princeton VSM is a piece of cake...
From my theorist perspective, it pisses me off to see all the experimentalists that get PhDs without having the slightest clue of what they've done.
Or Nobel prices...
Why does everyone constrain physics into Theory and Experiment? What about those of us that do Computational Physics? You know, like lattice QCD? Our work is necessary and important, but I can guarantee it'll never get a Nobel.
Hey! What about spin glasses!
I am happy to see the physics community speak up when others spill out some unfunded blurbs...
I've submitted several purely empirical papers to PRB and a couple papers to PRL and, with one exception, they came back with a requirement to include DFT calculations - just to "strengthen the discussion". Huh? As if one could just simply go and start doing ab initio calculations. For some reason, the same rules do not seem to apply to purely theoretical papers. No-one's asking these guys to go and conduct some experiments just to "strengthen their discussion".
I beg to differ. If you submit a paper to Phys. Rev. Letters which only contains theory you better have an experiment to back you up or you better SUGGEST an experiment. Otherwise it will be deemed "not interesting for a general audience" and trashed.
What I do not like in your arguments is the aftertaste of theory versus experiment, as well as theory is evial and experiments are underrepresented. Just as an example look at the most prestigious journals: in Nature and Science most papers are experimental. As a theorist you can most of the time just dream of an article there. Why? because it *is* easier to measure a novel effect than to think of a way of explaining it.... And this takes us back to the beginning of my previous posting: the best Nature papers are those where theorists and experimentalists COLLABORATE on a problem and present a nice picture.
I am glad to read that another physicist agrees with my opinions. It always amazes me the things some people write without educating themselves and it hurts to see they get a Score of 4 for that.
As an undergraduate in Zurich I once met Abrikosov because the "Russian Mafia" (Ivlev, Lesovik, Feigelman,....) seems to like this town. Really nice guy.
Cute side story: the original paper of Abrikosov predicts a square vortex lattice. He made a little mistake...
Let me elaborate a bit on your rather narrow-minded comment: superconductivity (SC) was discovered 1911 by K. Onnes. Not until 1935 F. London came up with a macroscopic description of the effect which explained the magnetic part of the problem, but not much further than that. 18 years leater in 1953 Ginzburg and Landau came up with a phenomenological approach (GL theory) which actually explained MANY things without the knowledge of the underlying microscopic mechanism. This was a great breaktrough because you could actually start to PREDICT things without knowing how it really worked in the guts. In particular they were of great importance in realizing that there are two types of SCs (I and II) from which only type II are relevant for industry. Type I "die" soon with small fields and have transition temperatures which are only a few K. Even though in 1957 Bardeen, Cooper and Shriffer (BCS) explained the microscopic theory of SC, GL theory remained one of the most important approaches to understand novel phases, such as the intermediate (Abrikosov) vortex phase in type II SCs. Type II SCs are important in industry because they remain superconducting for high fields. Problem is, you get vortices in the system. Abrikosov (who got also a Nobel medal) was the first to predict that these vortices make a lattice and constitute a NOVEL state of matter (within matter). In the meantime one has als high-T_c superconductors (the stuff MRI machines use) and for these NEW materials there is NO understanding on how SC works. BUT for these materials the Ginzburg Landau theory still applies and often makes predictions on how things will behave. Therefore THEORY IS IMPORTANT and these gentlemen deserve the award. As for Legett: he made important contributions in the world of superfluids as well as Bose Einstein condensation. IMHO his work on quantum tunneling with dissipation is the best. To summarize: no MRI with no GL theory.
As for your little rant: Theory and Experiment (and today also computational physics) should be COMPLEMENTARY to each other. You find many theory papers which do not seem to be close to reality. This does not mean they are garbage. It means that they are ahead of industrial applications. Often one sees experimental papers which simply say: "I measured this and look how cute it is". but they lack of ANY physical understanding. Now you tell me, which one is worse? Clearly Math is the language of Physics. But you need to know how to write in a languagel before you can create a nice poem... If as an experimentalist you do not even know how to "write", how can you then understand the theory pertinent to your experiment? All you are at that stage is an observer... and as we all know: everyone can observe.
It seems as if some experimentalists carry a large chip on the shoulder???
it might be that i added too much nitrogen which is why the stuff did not come out as creamy as others advertize. still, i was not too impressed by the speedup (KRUPS machine has it for you in 20 minutes as well) nor the quality. it was a bit "icy".
there are two problems with making icecream with liquid nitrogen: first, you cannot buy nitrogen at 7-11, you need to either work in a lab or have a friend who does (the latter being my case). second, good icecream is generated by continous stirring of the stuff while it slowly freezes. in this fashion the batch freezes in a polycristalline state and not in one giant single-crystal slab. this is very important as good icecram is supposed to smooth in texture and not "icy". it is almos impossible to do this with the liquid nitrogen version because things freeze too fast. from my experience i have learned that the best ice cream maker is made by KRUPS: stick the bowl into the freezer overnight (or into liquid nitrogen if you want to speed things up!) and enjoy a full batch the next day of the flavors you like. of course you could run into the store and buy some icecream, but do you know what is in that stuff?
i agree with all you write but have to insist that one can show the equivalence of vdW and casimir forces. after all, i wrote my undergaduate thesis on that. : )
before i forget: i recommend the book by mostepanenko and trunov. and of course, the standard work "The Casimir Effect" by k. a. milton has a whole chapter devoted to equivalence of the casimir effect and van der Waals forces. happy reading, if you understand it.
as you write, the casimir force is a quantum effect. still, there is more than just the textbook formula you wrote down for the forc between two plates. note that there are also *repulsive* casimir forces.... in any case, i am too lazy to elaborate and would like to refer you to the work of lamoreaux.
just to add more confusion to the story... one can show that the casimir force between two objects can also be viewed as a van der waals force. imagine two dielectrics separated by vacuum. in the casimir picture, the two dielectrics will attract because of vacuum zero-point energy fluctuations. as someone else pointed out earlier, this is, in very simple terms, because certain frequencies are not allowed in the vacuum creating a pressure. on the other hand, one can also generate the same force by having the particles in the dielectricum fluctuate, i.e. generate van der waals forces due to "dipoles".
from a physics point of view one has a hamiltonian (function which describes the whole system) for which one can integrate out the degrees of freedom of the dielectric or the degrees of freedom of the electromagnetic vacuum. if you remove the dielectric degrees of freedom, you get equations for the EM field which will give you a casimir force when you look at the cero point energies of the system with and without the dielectricum. if you integrate out the field, you will get an effective interaction term for the dielectrica and hence a vdW force.
note also, that both, van der waals and casimir forces depend with a power law on the distance between the objects, usually at a high power and are therefore extremely short-ranged. there are some nice papers and experiments measuring both at the usual archive xxx.lanl.gov. just search for casimir...
dear mr. brown,
first, i would like to thank you for one of the best cooking shows i have seen in a long time. my wife and myself, both geeks (physics & astronomy) do not miss a single episode of your show. as we are moving overseas we are hoping that europe's cable listings have food-tv.
my question is: in your show things seem to work out perfectly every time. this, of course, is a result of your scientific approach and exact work. still, i wonder how you rehearse for such a show and how many times you have to bake the souffle before it comes out puffy.
having tought science before, i admire the simplicity with which complex processes, such as gelation are explained in your show. do you cook up these explanations yourself or do you have a team of scientists to back you up?
thanks, h.
Slashdot Mirror
cowards.
to all editors: feel free to label this response as troll. i just get annoyed by posts which
a) have absolutely no content and are completely unfunded and
b) morons who do not know jack shit about someting.
finally, i would have expected more cojones than an anonymous post. slashdot: do us all a favor and delete comments from the anti-slashdot morons. freedom of speech? where? in the internet? ha!
i have worked a bit in the field of nano-decorated surfaces. it is impressive that one can make little nano-sizes arrays of magnetic dots on some substrate . this as so small, that one can view them as single particles which switch homogenously. hence you can study the interactions of little magnetic particles in arrays and do experiments which are very close to theoretical models, such as the Ising model. why should you care? because this nano-patterns seem to be interesting for exchange biased systems. and these seem to be interesting for the recording media industry. but why should you care... this is too geeky anyways. this guy (AKA Prof. Kai Liu) at UC Davis does some interesting research with nanostructures... cool pics and some explanations...
nice post... not just "good word of mouth". if you actively are participating in mailing lists and filing bug reports (like i used to do) then you are actually rewarding them for a product. money is not the only currency, but i guess we are the only two who think that way.... : )
i have been in contact with redhat directly about this. what they say to the media is not quite what they tell the customer: "we do not endorse RHPW and so cannot give you any info about it". as for site licenses, no official word yet...
your question makes sense and does not. if i use redhat and am happy, then i will recommend it to others, potential paying customers. if i am not happy, i will make bad publicity for them. it is a matter of the definition of "customer", but if you provide me with a service, regardless if i pay for it or not, i am your customer.
think about it: RH claims 90% of their customers are loyal because they are keeping their subscriptions. the important question is:
How many customers of RH did actually pay for a subscription before the change? And from those how did not pay (but were loyal Rh customers), how many are sticking with it?
The ones who paid before the kaboom do not care in spending bick bucks. The users who supported redhat but could not afford such a pricey OS definitely will not stick with it -- as it is the case in Academia! If RH were smart, they would offer site licenses for academia and big clusters.
I am willing to be my officemate (he is a good catch) that from the RH users who did NOT pay in the first place, 90% will switch to another OS if RH does not offer something "in-between". How about also releasing this information, RH?
(As one always learns in statistics: the outcome depends on HOW you present the data, and not what it actually looks like...)
i have been using spamassassin for a year and it works great! granted, in the beginnings about 18% of the spam (in my case 18% of about 30 emails per day) would get trough. BUT if you read the manpage and tweak with the different scores a bit, you can get that down to 1 - 2% with about the same amount of false positives. as an admin, you should be able to tweak any spam filter to match your needs best.
what i can highly recommend is to increase the score of MICROSOFT_EXECUTABLE as it generally is a piece of spam. in addition the bayesian statistics are a great idea: a spam filter that learns!
as for the reviewer: if it takes this person 10 times longer to read a manpage and punch in some trivial scores into a trivially set up configuration file, then you should take his review with a HUGE grain of salt... especially since he reviewed an ancient version of the software.
finally a general comment about spamassassin: EXCELLENT software, especially for the bargain price of $0.
yet again it seems that academia bites the dust. redhat seems to have moved over to corporate servers, yet they do not want to offer a "service-less" product for academia. we do not need service from redhat, we need a GOOD and STABLE OS for a REASONABLE price -- and updates, of course.
So please, RH, think over your policies. Academia is a big market and we like redhat, so do not take us away from you.
As a side note: I called RH UK last week Thursday. I am still waiting for the promised email from Mrs. Alonso regading my questions about RH Professional Workstation, which seems to be the answer academia is waiting for. All I need to know is if RH is willing to sell their RHEL WS software with access to up2date for a reasonable price and what the licensing conditions are. Can we buy more RHN subscriptons and get just one package???
did you notice the palm 515 review as part of a "headline"? that thing has been out for years!!! there are two pics below... i wonder how they choose their stories, but as far as i am concerned, i will swtick to google news for the time...
I am in the same boat! RH basically dropped academia from their list. We are thinking about migrating to other Linux versions or MAC OSX....
Excellent point! It would be absolutely great to do this!!!!
There are many long-time users of RH linux, such as myself, who over the years have relied on your company for mission critical applications of the OS (in my case my research as well as the computational clusters I use). Suddenly RH pushes their enterprise products and drops free software COMPLETELY. I have tested Fedora Linux and I do not think it is mature enough to run on mission critical applications. Clearly there are two options:
a) Pay for the yearly (!) $180+ license or...
b) Stop using RH Linux.
In my case, this will mean turning my back to RH and what I have heard from others, they intend to do the same. The corporate customers, who follow suggestions from their system administrators and who pay for a license, will probably follow in these footsteps because RH is becoming more and more corporate. Don't you think you basically started the end of RH with this move?
On the other hand I do not understand why I ask you this question: I already know your answer; "we do not make money with RH Linux and so we drop it and focus on Enterprise RH Linux". The problem is that most do not need help from RH to manage their systems -- unless they hire a windows sysadmin, and so, as I wrote above, your days are counted.
Having an experimental setup that no-one else in the world has is certainly a one way of getting a Nature of Science paper. However, to say that it's easier is quite an overstatement - unless you think it's easy to get funding for a prototype system costing several millions of USD.
As a theorist I *have* done experiments next to my analytical and computational work. And let me tell you: running a Quantum Design Magnetometer or a Princeton VSM is a piece of cake...
Yes, it is an ego thing, too. So what?
Get a massage and get over it...
From my theorist perspective, it pisses me off to see all the experimentalists that get PhDs without having the slightest clue of what they've done.
Or Nobel prices...
Why does everyone constrain physics into Theory and Experiment? What about those of us that do Computational Physics? You know, like lattice QCD? Our work is necessary and important, but I can guarantee it'll never get a Nobel.
Hey! What about spin glasses!
I am happy to see the physics community speak up when others spill out some unfunded blurbs...
I've submitted several purely empirical papers to PRB and a couple papers to PRL and, with one exception, they came back with a requirement to include DFT calculations - just to "strengthen the discussion". Huh? As if one could just simply go and start doing ab initio calculations. For some reason, the same rules do not seem to apply to purely theoretical papers. No-one's asking these guys to go and conduct some experiments just to "strengthen their discussion".
I beg to differ. If you submit a paper to Phys. Rev. Letters which only contains theory you better have an experiment to back you up or you better SUGGEST an experiment. Otherwise it will be deemed "not interesting for a general audience" and trashed.
What I do not like in your arguments is the aftertaste of theory versus experiment, as well as theory is evial and experiments are underrepresented. Just as an example look at the most prestigious journals: in Nature and Science most papers are experimental. As a theorist you can most of the time just dream of an article there. Why? because it *is* easier to measure a novel effect than to think of a way of explaining it.... And this takes us back to the beginning of my previous posting: the best Nature papers are those where theorists and experimentalists COLLABORATE on a problem and present a nice picture.
I am glad to read that another physicist agrees with my opinions. It always amazes me the things some people write without educating themselves and it hurts to see they get a Score of 4 for that.
....) seems to like this town. Really nice guy.
As an undergraduate in Zurich I once met Abrikosov because the "Russian Mafia" (Ivlev, Lesovik, Feigelman,
Cute side story: the original paper of Abrikosov predicts a square vortex lattice. He made a little mistake...
Let me elaborate a bit on your rather narrow-minded comment: superconductivity (SC) was discovered 1911 by K. Onnes. Not until 1935 F. London came up with a macroscopic description of the effect which explained the magnetic part of the problem, but not much further than that. 18 years leater in 1953 Ginzburg and Landau came up with a phenomenological approach (GL theory) which actually explained MANY things without the knowledge of the underlying microscopic mechanism. This was a great breaktrough because you could actually start to PREDICT things without knowing how it really worked in the guts. In particular they were of great importance in realizing that there are two types of SCs (I and II) from which only type II are relevant for industry. Type I "die" soon with small fields and have transition temperatures which are only a few K. Even though in 1957 Bardeen, Cooper and Shriffer (BCS) explained the microscopic theory of SC, GL theory remained one of the most important approaches to understand novel phases, such as the intermediate (Abrikosov) vortex phase in type II SCs. Type II SCs are important in industry because they remain superconducting for high fields. Problem is, you get vortices in the system. Abrikosov (who got also a Nobel medal) was the first to predict that these vortices make a lattice and constitute a NOVEL state of matter (within matter). In the meantime one has als high-T_c superconductors (the stuff MRI machines use) and for these NEW materials there is NO understanding on how SC works. BUT for these materials the Ginzburg Landau theory still applies and often makes predictions on how things will behave. Therefore THEORY IS IMPORTANT and these gentlemen deserve the award. As for Legett: he made important contributions in the world of superfluids as well as Bose Einstein condensation. IMHO his work on quantum tunneling with dissipation is the best. To summarize: no MRI with no GL theory.
As for your little rant: Theory and Experiment (and today also computational physics) should be COMPLEMENTARY to each other. You find many theory papers which do not seem to be close to reality. This does not mean they are garbage. It means that they are ahead of industrial applications. Often one sees experimental papers which simply say: "I measured this and look how cute it is". but they lack of ANY physical understanding. Now you tell me, which one is worse? Clearly Math is the language of Physics. But you need to know how to write in a languagel before you can create a nice poem... If as an experimentalist you do not even know how to "write", how can you then understand the theory pertinent to your experiment? All you are at that stage is an observer... and as we all know: everyone can observe.
It seems as if some experimentalists carry a large chip on the shoulder???
it might be that i added too much nitrogen which is why the stuff did not come out as creamy as others advertize. still, i was not too impressed by the speedup (KRUPS machine has it for you in 20 minutes as well) nor the quality. it was a bit "icy".
some guy on slashdot == a physicist...
there are two problems with making icecream with liquid nitrogen: first, you cannot buy nitrogen at 7-11, you need to either work in a lab or have a friend who does (the latter being my case). second, good icecream is generated by continous stirring of the stuff while it slowly freezes. in this fashion the batch freezes in a polycristalline state and not in one giant single-crystal slab. this is very important as good icecram is supposed to smooth in texture and not "icy". it is almos impossible to do this with the liquid nitrogen version because things freeze too fast. from my experience i have learned that the best ice cream maker is made by KRUPS: stick the bowl into the freezer overnight (or into liquid nitrogen if you want to speed things up!) and enjoy a full batch the next day of the flavors you like. of course you could run into the store and buy some icecream, but do you know what is in that stuff?
i agree with all you write but have to insist that one can show the equivalence of vdW and casimir forces. after all, i wrote my undergaduate thesis on that. : )
before i forget: i recommend the book by mostepanenko and trunov. and of course, the standard work "The Casimir Effect" by k. a. milton has a whole chapter devoted to equivalence of the casimir effect and van der Waals forces. happy reading, if you understand it.
as you write, the casimir force is a quantum effect. still, there is more than just the textbook formula you wrote down for the forc between two plates. note that there are also *repulsive* casimir forces.... in any case, i am too lazy to elaborate and would like to refer you to the work of lamoreaux.
just to add more confusion to the story... one can show that the casimir force between two objects can also be viewed as a van der waals force. imagine two dielectrics separated by vacuum. in the casimir picture, the two dielectrics will attract because of vacuum zero-point energy fluctuations. as someone else pointed out earlier, this is, in very simple terms, because certain frequencies are not allowed in the vacuum creating a pressure. on the other hand, one can also generate the same force by having the particles in the dielectricum fluctuate, i.e. generate van der waals forces due to "dipoles".
from a physics point of view one has a hamiltonian (function which describes the whole system) for which one can integrate out the degrees of freedom of the dielectric or the degrees of freedom of the electromagnetic vacuum. if you remove the dielectric degrees of freedom, you get equations for the EM field which will give you a casimir force when you look at the cero point energies of the system with and without the dielectricum. if you integrate out the field, you will get an effective interaction term for the dielectrica and hence a vdW force.
note also, that both, van der waals and casimir forces depend with a power law on the distance between the objects, usually at a high power and are therefore extremely short-ranged. there are some nice papers and experiments measuring both at the usual archive xxx.lanl.gov. just search for casimir...
dear mr. brown, first, i would like to thank you for one of the best cooking shows i have seen in a long time. my wife and myself, both geeks (physics & astronomy) do not miss a single episode of your show. as we are moving overseas we are hoping that europe's cable listings have food-tv.
my question is: in your show things seem to work out perfectly every time. this, of course, is a result of your scientific approach and exact work. still, i wonder how you rehearse for such a show and how many times you have to bake the souffle before it comes out puffy.
having tought science before, i admire the simplicity with which complex processes, such as gelation are explained in your show. do you cook up these explanations yourself or do you have a team of scientists to back you up? thanks, h.
... http://antwrp.gsfc.nasa.gov/apod/ap020414.html