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However at least the Catholic church isn't dismissing the idea's, which is a long way from the outright attacks made by more fundamentalist churches. The thing about this debate is that while fundamental theist's attack science and the theory of evolution using doubt, no counter-argument is made that has any impact on the faith of proponents of Intelligent Design.

Science and Religion are different bodies of knowledge, but not mutually exclusive because both use reason as a tool for different goals. There are scientific people who are religious and religious people who are scientific. Making a science based argument about the ignorance of Intelligent Design to someone who has a predominately religious background make both sides dig their heals in. That's why this debate has become so polarised.

I've found that having an understanding of the doctrine that supports scientific investigation and framing that discussion so that it attacks the underpinnings of Intelligent Design an important tool. Building and demonstrating an understanding of the theocratic aspects of this debate is an important tool to disarming the proponents of Intelligent Design and helping them understand why science is important to their faith.

A scientific argument explaining the shortcomings of Intelligent Design to a religious person really just reveals their ignorance of science and, as such, they feel ignorant of science but it's not important to them.

A theocratic argument explaining the shortcomings of Intelligent Design to a religious person reveals the shortcomings of Intelligent Design when compared to the discoveries made by a study of Evolution.

When confronted with one of these discussions I point out that Intelligent Design limits how far humanity explores nature, or in theocratic terms "the works of God". I go on to point out that there is nothing in the Theory of evolution that attacks Christian beliefs but, in fact, uses science as a tool to uncover the amazing wonder of how nature works, or in theocratic terms "the glory of God".

It's at this point that proponents of Intelligent Design start to join the dots for themselves. The insecurity they feel about Darwin's idea's attacking their belief system give way to the possibility that Intelligent Design could actually be a form of blasphemy, something that is important to a religious person.

I think it's important to frame the debate this way because the Intelligent Design position cleverly deceives religious people into accepting ignorance over education and promotes the notion that science aims to dispel religion. Science and Religion have to co-exist in society if we are to dispel ignorance and fundamentalism.

Last I checked, the solar wind isn't a stream of electrons.

It's roughly equal numbers of electrons and protons, as I recall, with a very small amount of helium nuclei in the mix.

Some good graphs here

I'm assuming that if the moon was made from a fairly large amounts of ejected matter, that it would have formed from a gradual gravitational aquisition of the mass. Those other moons and planets that form this way have pretty large angular momentum.

Also important to note, the moon is pretty much tidally locked (the same side always faces the earth). It's inconceivable that Earth's gravitational field did not play an extremely key role in the current angular momentum of the moon. For more information, read the section Tidal Coupling in the Earth-Moon System in the linked article.

Well, we could go back and forth on this forever. In the end, 'weight' is a definition, and the definition I have been using is the commonly accepted one, in which an object in freefall has a weight of zero. If you don't believe wikipedia on this, there are links to other sites (including any number of NASA) sites elsewhere in this thread.

If you want to define weight differently you are of course free to do so, but do not expect to be able to use your term in a useful conversation! If you want to define 'weight' as the mass times the local gravitational field strength, ignoring motion of the object, then do you also include the (small but non-zero) contribution from the gravitational field of the Sun? Don't forget, that it acts in different directions (ie, either adding or subtracting to the conventionally defined weight) depending on whether the sun is below you (night time) or above you (day time). How would you define your weight on the moon, in your scheme? How does the gravitational field of the Earth (and the Sun, and Jupiter, and ...) affect it?

For your question on the acceleration of the rocket, you need to be careful to distinguish the frame of reference. You are completely correct from the frame of reference of the rocket: the impulse of the engines is assumed constant, so as the mass of fuel decreases the acceleration of the rocket increase. This holds no matter whether the rocket is in a gravitational field or not: unless the astronauts looked out the window to see there is no way they can determine whether they are in empty space, or accelerating away from (or towards!) a heavy mass (ie. they cannot determine this by performing experiments to measure the local gravitational field, in all cases they get the same answer! This is the equivalence principle, which is a cornerstone of general relativity).

From the frame of reference of an outside observer on the Earth, the motion of the rocket is certainly affected by gravity. For example, if the acceleration of the rocket just happened to be 9.81m/s^2 then the rocket would be not accelerating relative to an observer on the Earth - he would see it as hovering (or moving at constant velocity relative to the observer). But to the astronauts inside the rocket, they would feel the acceleration as indistinguishable to standing on the surface of the Earth.

What we feel as weight is not the downward force -mg but rather the upward force +mg which we have to exert to resist the downward one. This is what you feel when you do a push-up, for example. In freefall, the downward force -gm is still there, but there is no reaction force acting against it. No rection force = no weight.

This is why LTSP makes so much sense. You plug in a random crappy machine and either you can get it to remote boot via PXE or a boot CD/floppy or you can't. If you can't, you throw it away. And pretty quickly, the problem becomes space and electricity, so you can just stop accepting the ones that won't PXE boot.

http://learn.occ.utk.edu/~pfaffman/utk/proposals/cscl2009/ltsp-research-platform.pdf

Wrong. There is a world of difference between a supercomputer and a cluster. The network is not simply "faster" or "higher bandwidth." These things are custom-designed to fit the type of processing a supercomputer needs to do. These are not embarrassingly parallel codes. In fact, that's why the Top 500 is bogus. It ranks computers based on their ability to run an embarrassingly parallel code. We really ought to be measuring with something like HPCC.

The University of Tennessee system sustained an initial $21.2 million budget cut in June, followed by an additional October impoundment of $17 million. All campuses have been affected and have taken similar measures, of varying degrees of severity, to offset these reductions.

As a result of the initial cut, the Knoxville campus reduced its budget by $11,452,500; the Chattanooga campus by $2,682,200; the Martin campus by $1,965,000; and the UT Health Sciences Center by $2,751,500, according to the proposed budget for the 2009 fiscal year, released by the UT System Budget and Finance Office. Other UT branches affected included the Space Institute, the Institute of Agriculture, the Institute for Public Administration and the Systems Administration division.

I like to think of it the opposite way: RAID 5 is a special-case implementation of RAID 6. The parity calculation in RAID 5 work out to be a simple XOR, but the second (and third, fourth, etc) parity calculations in RAID 6 with two or more parities are significantly more difficult.

If you're interested in implementation, check out The mathematics of RAID-6 (pdf) by H. Peter Anvin, and A Tutorial on Reed-Solomon Coding for Fault-Tolerance in RAID-like Systems (pdf) by James S. Plank (I used these as references to write a RAID-6 implementation in Java).

http://www.math.utk.edu/~vasili/refs/darpa07.MathChallenges.html

Cheers

Just with a lot more dollars behind it...

Every one remotely engaged in Top500 systems knows how very specific the thing being measured is. It's most sensitive to the aggregate clock cycles and processor architecture, and not as sensitive to memory throughput/architecture or networking as many real world things are.

http://icl.cs.utk.edu/hpcc/

Is an attempt to be more comprehensive, at least, by specifying a whole suite of independently scored benchmarks to reflect the strengths and weaknesses of things in a more holistic way. Sure, it's still synthetic, but it can give a better 'at-a-glance' indicator of several generally important aspects of a supercomputer configuration.

The thing probably inhibiting acceptance of this is that very fact, that it is holistic and the winner 'depends' on how you sort the data. This is excellent for those wanting to more comprehensively understand their configurations standing in the scheme of things, but hard for vendors and facilities to use for marketing leverage. Being able to say 'we built *the* fastest supercomputer according to the list' is a lot stronger than 'depending on how you count, we could be considered number one. Vendors will aggressively pursue pricing knowing about the attached bragging rights, and facilities that receive research grant money similarly want the ability to make statements without disclaimers.

Rest assured, though, that more thorough evaluations are done and not every decision in the Top500 is just about that benchmark. For example, AMD platforms are doing more strongly than they would if only HPL score is counted. AMD's memory performance is still outrageously better than Intel and is good for many HPC applications, but Intel's current generation trounces AMD in HPL score. Of course, Intel did overwhelmingly become popular upon release of their 64-bit core architecture based systems, but still..

http://www.law.utk.edu/FACULTY/scope.PDF

Harvard Law Journal on Legislation. The duty to act is well cited.

Were I a college or university official selecting students from various national high schools, I would immediately exclude all graduates from the State of Louisiana starting three years hence. This would apply to all fields of study because science, along with reading, writing and mathematics, makes up a central core of educational training essential to High School graduation.

There is one simple reason: The students may not have been taught scientific rigor, that for a hypothesis to be proven it must be supported by observable, repeatable facts. And any science teacher who teaches that "science" permits a hypothesis or theory to be supported by wishing, conjecture, supposition, acts of unobservable forces and so on is not appropriately training students for any future in higher education. And I would have to say that it is not the job of my college or university to teach remedial science to students who ought to have been correctly taught the basics in high school.

I should mention that the Pope has stated that Darwin's theory of evolution [is] compatible with Christian faith. And anyone who has actually read Darwin's Origin Of Species By Natural Selection and The Descent Of Man will quickly come to the conclusion that Charles Darwin was a very religious man and couched his arguments in terms of his own beliefs, but never once deviating from scientific rigor in his statement of his hypothesis.

The Christian wing-nuts who would teach religion as if it were science have managed to confuse the English definition of the word "theory" with the scientific definition of that word. In English, the word allows for considerable uncertainty whereas, in science, a hypothesis becomes a theory only upon rigorous peer review and only when not disproved by physical evidence. During Darwin's lifetime, his book was always seen as a hypothesis and it graduated to the level of theory as actual evidence that supported his statements came rolling in.

There is genetic and physical evidence for Darwin's statements on natural selection. And we have evidence supporting evolution and none, whatsoever, for any other hypothesis for how plants, animals and humans appeared on the earth.

I would urge any college and university admissions offices to consider denying admission to any and all students who have not appropriately learned science, which means they have been taught to not follow the rules of scientific enquiry in schools in Kansas (in the past) and Louisiana (going forward).

There are different energy calculations for this. Calculated at STP, the number is about 38%. But in actual cellular conditions, the calculated value is anywhere from 50% to 70%, depending especially on the ratio of ADP to ATP.

Sorry, all the organic materials will not have decomposed. This is one of the many misconceptions about our waste stream. The compression of the trash generally results in an anaerobic environment, and it all mostly just.... stays there.

Here's a nice little summary about garbage myths that it looks like William Ruthje of the Tucson Garbage Project put together for high school students about misconeptions regarding trash. One of the particularly surprising and interesting things is the huge percentage of garbage that is actually just paper.

While the article seems to have been written in 1992 and I'm sure trash disposal streams have changed a bit, it gives the general idea and is quite an interesting read. The short of it is that there's a huge volume of stuff out there, and gallium, hafnium, and the like might very well turn out to still be small needles in a very large, stinky, toxic, and hazardous haystack for many years to come.

Another theory is that Moon was tugged into place to stabilize Earth.

There are several petaflop machines in their initial phases of roll-out right now, but peak performance isn't the only number worth paying attention to. The SX-9 is an amazing architecture, with orders of magnitude more bandwidth than the roadrunner system, both in interconnect, and in memory bandwidth. It's also a very expensive machine. The SX, however, has an advantage of being an update and refinement to a very established architecture. codes written for the SX-3 are going to perform well on the sx-9.

Roadrunner is a cool machine, but hard to program. You have most of your compute capability on the cell coprocessors, which are connected by a non-coherent infinaband pipe, to the host opteron processor. On the cell, you have a powerpc doing the program setup, and the 8 spu engines chunking through the data in parallel. If you can parallelize your program enough, you can get those working really quickly, but you have to do all the memory management in software, and control flow has to happen on the ppc. It's not impossible to get good performance from such a machine, but don't expect to just drop your existing software onto it and get decent performance. Blue gene is a less radical approach, and it took 3-4 years for a dozen codes to be rewritten to take advantage of it. Los Alamos runs a small number of applications, but needs a lot of performance. Thus they can spend the time to optimise their small list of apps for such a heirarchical design.

Also, you have your number off a little. The updated cell will provide 100Gflops of double precision performance, according to IBM. Still very fast. http://www.cs.utk.edu/~dongarra/cell2006/cell-slides/04-Ken-Koch.pdf
http://repositories.cdlib.org/cgi/viewcontent.cgi?article=4262&context=lbnl

Apparently, there were many, many unanticipated problems with lunar "dust".

http://news.bbc.co.uk/2/hi/science/nature/6460089. stm
http://apod.nasa.gov/apod/ap980327.html
http://dailybeacon.utk.edu/showarticle.php?article id=51367

As expected, enginerds never seem to want to underestimate a problem especially when they've heard of a similar problem before...

With Comcast I get (at the moment) I get 2416 Kbps outbound and 15315 Kbps inbound. This will drop after about 20 seconds of transmission due to the speed boost which has recently been put into effect on both inbound and outbound connections.

So PC Magazine has unfairly smeared Comcast, which is now giving stellar service.

Another issue is that Comcast uses AT&T's network, and when AT&T bought BellSouth, they agreed to net neutrality, which means that they now peer at many more locations with other networks. It used to be that my packets went twice across the country to go 10 miles from home to work. No longer :-)

Let's start with a Slashdotting of NASA...

• Scalable Dynamic Chimera Methods for Unsteady Aerodynamics is one of those packages mere mortals like us will have either no use for or will have to just drool over.
• Fully Unstructured Navier-Stokes 3D is a nice Fortran-based CFD, requires some hefty paperwork to obtain, and may need you to use G95 rather than GCC's GFortran, due to compiler bugs.
• OVERFLOW and related CFD software.
• Three Dimensional Multi-block Advanced Grid Generation System is the component that actually lets you do a lot of the necessary grid work for CFDs.
• Viscous Upwind ALgorithm for Complex Flow ANalysis is the hardest of the CFD codes at NASA to obtain, but if you want to work on anything hypersonic, it's the best place to start. Do Not Use hypersonic airflows for CPU cooling.

• Astrophysical Thermonuclear Flash Simulator - well, you never know.
• Geant4, for the subatomic nuclear physicist in your life...
• Open Field Operation and Manipulation is a nice open-source CFD package.
• Parallel Basic Local Alignment Search Tool gives you a parallelized search engine for nucleotides and proteins.
• Stanford Exploration Project provides some nice parallel geophysics applications and tools.
• Tachyon Parallel Raytracer is a nice example of what you can do with parallelism and graphics.

• Kerrighed is an up-and-coming clustering system for Linux. I saw it demonstrated at SC|05 - and was less than impressed. It needed a lot of work at that point. However, it looks like it has improved a lot since then, and it would be unreasonable to not mention it.
• MOSIX is the second-oldest clustering technology to gain a fan following to rival Star Trek. It's very good, though hard to get if you're not in academia. Arguably for entirely fair reasons.
• OpenMOSIX was originally a fork from MOSIX but is now essentially its own clustering technology. Development is nowhere near the speed I'd like, it does need far more eyes, but is well-known and highly regarded. Moshe Bar is also one of the coolest developers I've encountered.

• DAKOTA is a program for profiling parallel applications and should be useful in telling you where you are gaining and losing.
• HPC Toolkit is another toolkit for profiling HPC applications.
• is yet another profiler for parallel software. Between this and the others I've listed, you should have more information than sequential programmers ever get to work with.
• Performance API is a facility used by most of the profiling software to provide an architecture-independent view of performance counters. I have it on good authority that some (now former)

Way before you run into any relativistic effects--or even the speed of sound inside the pole--basic 17 century Newtonian physics will make the process less than instantaneous.

Also, thanks to Newton's Third Law, space is like Soviet Russia: In space, the pole pushes you.

Because although they didn't mind our presence, they weren't very snuggly, thereby missing out in the burial process, where dogs and cats won.

For some reason, as ridiculous as this museum seems to me, I don't see it as a threat to science. Folks ignorant enough to buy it would be that ignorant anyway, or they're the absolutist type who can't comfortably marry science and theology in their lives (funny because that type of reasoning, devoid of theological imagination, has spawned a "science" of creationism, which is forced to be incredibly fanciful to explain itself). It really is kind of a last gasp, like when the church was scrambling for geocentric arguments against Copernican cosmology--piling epicycle upon epicycle to explain each newly discovered kind of movement (even though Copernicus didn't do away with epicycles completely). This museum will be a very interesting anthropological throwback--a delicate and desperate collection of epicycles for our own time.

Look at the bottom of this link. Dark matter and antimatter are two separate issues. Antimatter was verified with the observation of the positron that you mention in the 1930's and the existence of antimatter hasn't really been debated since then. Dark matter is something totally different... it's existence is suggested by astrophysical data and not by experimental particle physics. There is no theoretical understanding of dark matter. It's all suggested by observation. Of course, that's the way science is supposed to work, but in a few cases theoretical understanding preceded observation, as was the case with antimatter.

MuPAD light seems to still be around, if you look hard enough :)

Yes it does make sense. Li, Be, and B are all unstable at the temperatures at the core of a sun. Lithium with an amu of 6 literally falls apart extremely quickly inside a sun. At any rate, 3He, 7Li, 6Li Be and B are actually formed by spallation of other elements due to cosmic ray collisions. As another reply states go here: http://csep10.phys.utk.edu/astr162/lect/energy/tri plealph.html

After Carbon is formed alpha particles fuse with the Carbon, Oxygen, Neon and so on, until Iron is formed, note that all along this path no odd number elements are formed. Iron is at the dead bottom of the nuclear energy potential graph. This means that it actually takes energy to fuse Helium with Iron to make Nickel. Where do Nickel and all the other odd numbered elements aside from Li and B come from? Well since it takes energy to make Nickel, when a super giant star undergoes a supernova at the end of its life there is plenty of energy to go around. When a supernova occurs the implosion and subsequent explosion leaves lots of energy to form Nickel, Uranium and Tungsten for example. Add a few odd protons fusions and you get the odd numbered elements too. The event of a supernova is really the only way you can form the oddball elements by fusion. Nuclear decay can also produce oddball elements, those elements with masses above Iron or that are odd numbered, but the vast majority of the oddball elements are produced by fusion during a supernova. This is probably the reason why odd numbered elements are 10 times less abundant than the adjacent even numbered elements.

As an aside, (and oh boy is this offtopic) all elements have chemical properties that make them concentrate under certain conditions that from what I have seen really only exist or at least used to exist on only Earth. This is why I find the concept of mining asteroids pretty absurd. While there are three types of asteroids (carbonaceous, stony and iron-nickel), they are all pretty undifferentiated and there is little or no concentration of economically useful elements, like for instance Aluminum. We have all the iron we will ever need in Precambrian iron reefs that dot every continent and there is very little call for more carbon, or for that matter chunks of undifferentiated basalt. Mining Mars *may* make sense, but all it appears to be made of is basalt or mechanically weathered basalt, but little to no *chemically* weathered basalt.

The problem is one of sorting and concentration. Chemical sorting can occur from running water, cooling magma, or other ways. Running water at different acidities and oxidation states is how some elements are sorted. This is important and neither of these has occurred on an asteroid and very little has probably occurred on Mars. The concentration of an element is what is important. Without a rare element, like Aluminum, being concentrated by several times from its percentage of natural occurance, the cost of refining Aluminum from an asteroid would be several times more than it would be to just mine it from terrestrial Aluminum ore. Suppose someone told you that there was five tons of Gold distributed evenly in a big block of Iron, it would be worthwhile to obtain the Gold if the block was only ten tons, but if the block was 10,000,000,000 tons one would just walk away, it would never be worthwhile to refine the Gold. The point is that unless someone finds an asteroid that is made purely of gold, be sure to ask how they intend on removing all of the impurities from the asteroid and how their method is going to be cost effective versus preexisting terrestrial methods. Most discussions on asteroid mining don't seem to acknowledge this point at all.

Mod the parent up. It's called the triple alpha sequence (process)... and has been written about since the 50's.

http://csep10.phys.utk.edu/astr162/lect/energy/tri plealph.html for more light reading.

Amen, brother.

For people not familiar with MySQL's history, I would suggest a little reading from previous versions of MySQL's manual:

How to cope without COMMIT/ROLLBACK: For the moment, we are much more for implementing the SQL server language (something like stored procedures). With this you would very seldom really need COMMIT-ROLLBACK. This would also give much better performance.

Reasons not to use foreign keys. There are so many problems with FOREIGN KEYs that we don't know where to start.

I decided long ago that the MySQL guys are clowns. MySQL's lack of features was never as big a problem as the fact that I just couldn't take these guys seriously (and the above is only a small subset of the reasons for that).

Amen, brother.

For people not familiar with MySQL's history, I would suggest a little reading from previous versions of MySQL's manual:

How to cope without COMMIT/ROLLBACK: For the moment, we are much more for implementing the SQL server language (something like stored procedures). With this you would very seldom really need COMMIT-ROLLBACK. This would also give much better performance.

Reasons not to use foreign keys. There are so many problems with FOREIGN KEYs that we don't know where to start.

I decided long ago that the MySQL guys are clowns. MySQL's lack of features was never as big a problem as the fact that I just couldn't take these guys seriously (and the above is only a small subset of the reasons for that).

• "Traces of Catastrophe: A Handbook of Shock-Metamorphic Effects in Terrestrial Meteorite Impact Structures", Bevan M. French (Smithsonian Institution), http://www.lpi.usra.edu/publications/books/CB-954/ CB-954.intro.html
• "Stalking the Wily Shatter Cone: A Critical Guide for Impact Crater Hunters", Bevan M. French (Smithsonian Institution), Impact Field Studies Group newsletter, Winter 2005, online at http://web.eps.utk.edu/ifsg_files/newsletter/Winte r_2005.pdf
• "Shatter cones: Branched, rapid fractures formed by shock impact", Amir Sagy, Jay Fineberg, Zeev Reches, JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109 2004, online at http://www.agu.org/pubs/crossref/2004/2004JB003016 .shtml (for a fee), http://www.whoi.edu/science/GG/geodynamics/2005/im ages2005/sagy04_JGR.pdf, http://earthquakes.ou.edu/reches/Publications/Sagy _JGR.pdf, and others

Another example:

Caulerpa Algae spreading wildly in the Mediterranean sea.

Indeed. Whenever someone questions the utility of some basic research I remind them of GFP. Glowing jellyfish? Neat but hardly a useful discovery. Only now GFP fusion proteins are being used to track single vesicle trafficking inside a living cell. Or with BRET you can measure protein-protein interaction in real time.

Also there are restriction enzymes. Primitive bacterial immune systems seems like a niche field, but without restriction enzymes much of our genetic technology would not be possible. What other fields have yielded completely unexpected and invaluable results?

Something (kind of) similar happened to me, and I wrote up a little web page on my experience. The experience itself provides an interesting story, but afterwards Comcast (who the story was about), got mad and threatened to sue me. I got scared just like Spocko, but talked to a lawyer and he told me Comcast's bullying is just that and they didn't have much to actually do other than that. Anyway, the first (long) part of the story is just the bad experience where I whine a lot, heh. Maybe you'll find it a good story. Anyway, scroll down towards the bottom to see where they threaten to sue me and where I bravely (stupidly?) try to stand up to them. It's been a year and still no lawsuit! http://www.cs.utk.edu/~jthomas/cableguy/cable.html

This is a good explanation of how the Earth's magnetic field influences particles from the Sun and it's from a University:

http://csep10.phys.utk.edu/astr161/lect/earth/magn etic.html

String theory is a scientific theory that has neither been proved nor disproved to my knowledge.

I could speculate all day on whether or not it is fact but from what I've read, I will make a few statements. It seems that string theory was invented to satisfy some things we could not explain. This doesn't mean it's wrong or right although some people will contend that it is most probably wrong.

As the summary points out, few (if any) of String Theory's propositions can be tested or even observed. So it is simply an unknown right now. We cannot measure the proposed strings so how can we prove if they exist or they don't? We simply can't yet.

A good analogy would be Bohr's early assumptions about the atom. They were wrong but they were a step in the right direction. In hindsight, we see this now but we don't know what the future holds for String Theory. I'm just glad there are people out there thinking outside the box.

Do not fret, however, as scientists have been very resourceful at proving/disproving theories. I submit, for example, the exercise of determining the diameter of the building blocks of matter. Scientists had the idea to fill up one cubic milliletre of oil and dump it on top of a trough of water with a roller across the top. As the oil spread out, they moved the roller further down the trough. Once they started to see non-reflective parts of the water, they moved it back until they agreed the oil was completely spread out to the best of their abilities. Using this area, they determined how thick a molecule of oil could be without precision tools!

Similar ingenious tests have been devised to easily find the diameter of the earth at sunset on a beach with a yard stick or ruler.

So even though we may never be able to measure these strings, there are still some options left to explore to record properties that may prove/disprove their existence. We're merely in the very early stages of the scientific process.

Let us be excited about String Theory, even if it is wrong it sure is interesting. Nothing's wrong with a scientist who dreams, is there?

Unfortunately this seems to be one of the topics that the slashdot bias and ignorance comes out in full force on.

I agree completely.

* Clusters can not compete with supercomputers. They aren't even in the same market space. Cray doesn't make clusters, and clusters have not taken away their business.

This is not exactly a wrong statement, but it is incredibly broad. First off, Cray does make clusters. At a fundamental level, the basic separate-box clusters connected by Ethernet are the exact same thing as a big massively parallel system. They are on different ends of the spectrum, certainly. The sort of interconnects used by Cray certainly make their systems much more suited to certain workloads than more basic clusters. In practice, even Single System Image vs. separate boxes isn't that big a distinction. And, basic clusters certainly do compete with and take business from Cray. If basic clusters weren't an effective means of computing, then there would be a much larger market for the supers. If I refer to "clusters" in this post, I am probably referring to separate-box basic clusters -- like the parent poster seems to be. As unclear as this terminology can be, it is the way the term is usually used.

* Cray doesn't take off the shelf hardware and sell it as fancy clusters. Actually look into the details of these machines. While processors sometimes are off the shelf much of the surrounding hardware and software is custom.

This point I fully agree with. The high end interconnects and whatnot that you see in supers are on a very different level from what you see in the more basic clusters. For the workloads where the supers kill the basic clusters, it's usually related to comms latency between the nodes, which is all about the crazy interconnects.

* This 50 million contract is one of many that cray has. They also just recently in the news got a 200 million dollar contract. They also are a contender in the DARPA HPCS thing. That could be a lot more if they get it. They aren't dieing.

I'll take your word for it. I haven't specifically kept up with Cray's contracts, though it wouldn't surprise me if they are doing pretty well.

* They aren't owned by SGI any longer. They were bought from SGI by Tera who renamed themselves cray.

Yup, no argument there. (See, I may be a jerk, but at least I'm not arguing with everything! ;) )

* The top500 list is nonsense. It is based off of 1 benchmark (linpack.) That benchmark doesn't stress the interconnect too much and can allow clusters to appear to compete with supercomputers if you manage to ignore all the other factors. The number of teraflops has very little to do with performance. To see a more well rounded and thought out measurement of top systems check out HPCC's website. http://icl.cs.utk.edu/hpcc/hpcc_results.cgi

I wouldn't go so far as to call top500 "nonsense." It is a very specific benchmark. People do tend to look at a very narrow, specific piece of information, and generalise it completely. *That* is nonsense. You have to be aware of what you are reading when you see stuff like benchmark numbers. Benchmarking can be very complex.

That said, there are some real world workloads that work quite a lot like linpack. Consequently, there are a lot of very real world tasks where a cluster is an appropriate tool. My personal interest in HPC tends to focus on 3D rendering performance. This tends to need a lot of FLOPS, and relatively little bandwidth. For the guys who are doing really bandwidth/latency intensive stuff, the basic clusters are useless. (I'm told that stuff like weather sim falls into this category, but I can't comment on the details.) Without specifying a workload, saying th

Unfortunately this seems to be one of the topics that the slashdot bias and ignorance comes out in full force on.

* Clusters can not compete with supercomputers. They aren't even in the same market space. Cray doesn't make clusters, and clusters have not taken away their business.

* Cray doesn't take off the shelf hardware and sell it as fancy clusters. Actually look into the details of these machines. While processors sometimes are off the shelf much of the surrounding hardware and software is custom.

* This 50 million contract is one of many that cray has. They also just recently in the news got a 200 million dollar contract. They also are a contender in the DARPA HPCS thing. That could be a lot more if they get it. They aren't dieing.

* They aren't owned by SGI any longer. They were bought from SGI by Tera who renamed themselves cray.

* The top500 list is nonsense. It is based off of 1 benchmark (linpack.) That benchmark doesn't stress the interconnect too much and can allow clusters to appear to compete with supercomputers if you manage to ignore all the other factors. The number of teraflops has very little to do with performance. To see a more well rounded and thought out measurement of top systems check out HPCC's website. http://icl.cs.utk.edu/hpcc/hpcc_results.cgi

* Bluegene doesn't kick Cray's ass. See the above and then see how it really performs overall. In some areas it does better and in others it just gets destroyed. Depending on the real world problem a full size blue gene may not even be able to perform as well as a much smaller Cray.

If you don't know what you are talking about look it up before posting. Just because it's the common belief doesn't mean there is any truth to it!

I do hope some cosmologist answers this better than I will, but this conundrum was addressed in part by a then-radical idea proposed by MIT professor Alan Guth (he lectured my freshman physics class, in part) who suggested that for a brief period right after the Big Bang, the universe expanded at much faster than the speed of light. This theory is called The Inflationary Universe, and although no one seems to understand why it might be the case, it's one of the few theories that explains things like why the universe is so big, why it's so very nearly flat, and why it isn't all exactly the same temperature and density.

For more information see http://csep10.phys.utk.edu/astr162/lect/cosmology/ inflation.html .

"Our results demonstrate that genomes encode an intrinsic nucleosome organization and that this intrinsic organization can explain approx 50% of the in vivo nucleosome positions.

But if we already could, then presumably we already would, and there wouldn't be any arguing about whether it was possible or not.

That's not necessarily the case. There are a lot of things that are marginal and poorly understood. Take color vision. We've known about color-blindness for a while. But did you know there are people with more color vision than you? To them, we're the color-blind ones. We also don't really understand the idiot savant phenomenon yet. We are an organism only partly understood and under vigorous evolution.

That's no reason to assume that we are latent telepath mutant supermen, of course. Just that we shouldn't rule it out a priori. People should feel free to keep looking until everybody's satisfied that there's nothing there, which presumably won't happen until we have a complete mapping of brain function and a roughly finished theory of consciousness.

Two hundred years ago such questions would have made sense. Today we know there isn't any mechanism for that.

This is an argument from ignorance. You're saying that you haven't seen a mechanism, therefore one doesn't exist.

Can you honestly tell me that in a universe where 90% of the matter is, by our best science, missing - there is no possibility that we may have overlooked something?

Remember, less than a hundred years ago we thought radio traveled through the luminiferous ether. And at the time, it made sense.

pics start on page 5 of this pdf file..

http://plasma.ee.utk.edu/~plasma/publi/AFOSR_repor t.pdf

The work here is to show that a plasma generated near the leading wing edge prevents the seperation of the flow.. feel free to pantent this application for fans :P

There's a great article with pictures of the Earth's magnetic field at: this UK physics site...scroll down to see the "bow shock," but there's no picture of the tail, they cut the picture off early. A great animation of the Sun's impact on the rotating magnetic field of the Earth can be seen at this NASA site.

There is, in fact, a fusion reaction for hydrogen-1, but it is entirely impractical for terrestial power production. Feels good when sunbathing, though.
http://csep10.phys.utk.edu/astr162/lect/energy/ppc hain.html

..can be gotten from the results of the 2005 HPC Challenge - real world results, no marketing blurb.

2000 hours over 10 years is 200h:y, or 33 minutes per day. That's not so heavy use among the people I know.

But what about Bluetooth? People wear headsets inserted into their skulls, along a canal closer to the brain, against a transparent auditory nerve hole. All day long. It's a different frequency, and different power level than cellphones. There isn't 10 years of data yet. But why should we wait?

Swedes already know the damage Bluetooth can cause in the name of bringing everyone together. Let's see the official damage tally.

Joel Lubar at U.Tenn.

http://psychology.utk.edu/people/lubar.html

It's hardly unusual for NASA to be involved in "breakthrough" science that they had no idea already existed.

The Bohr Atomic Postulate is probably a reference to the Bohr Atomic Model:
http://csep10.phys.utk.edu/astr162/lect/light/bohr .html

The Bohr Model is probably familar as the "planetary model" of the atom illustrated in the adjacent figure that, for example, is used as a symbol for atomic energy (a bit of a misnomer, since the energy in "atomic energy" is actually the energy of the nucleus, rather than the entire atom). In the Bohr Model the neutrons and protons (symbolized by red and blue balls in the adjacent image) occupy a dense central region called the nucleus, and the electrons orbit the nucleus much like planets orbiting the Sun (but the orbits are not confined to a plane as is approximately true in the Solar System).

My friends who have been to law school have become, ah, lawyers, judges, investigators, and venture capitalists. Law school sharpens the mind and teaches analysis and discipline and ethics (yeah, I know - lawyer jokes).

One man I've never met except virtually via email exchanges is Glenn Harlan Reynolds. He is on the University of Tenn Law Faculty, and writes (very well and) prolifically about technology. Send him a note - maybe you'll get an encouragement.

Another guy with a law degree who writes about a field completely tangental is Robert Freitas.

But do whatever you do, do it at your own pace.

Documentation like this is great and extremely valuable. It would be much more valuable, however, if it remained current. For example, can the ABISS project (which improves block I/O) be used at all? What do the numbers look like, when using profiling tools like Web100 (which profiles TCP communications)?

Has anyone run the Linux or one of the *BSD kernels through DAKOTA, KOJAK or PAPI to determine where, precisely, bottlenecks are within the kernels? It's easy to theorise, but isn't it cleaner to measure?

Now, I'm not saying these things aren't being done. They probably are, somewhere, by someone, but if the results aren't getting published we don't really know what impact what changes are going to have. The current method of evolving Operating System code in general is often a mix of personal theory and subjective experience based on non-random samples of activity. That can't really be a good way to do things, can it?

If I'm wrong, feel free to say. If I'm right, then maybe it would be a good thing if someone (possibly me) put together some kind of testing kit for measuring Linux kernel performance and actually measured the stats for Linux kernels on some kind of regular basis.

"The solar spectrum consists of a continuum with thousands of dark absorption lines superposed. The lines are called the Frauenhofer lines, and the solar spectrum is sometimes called the Frauenhofer spectrum. These lines are produced primarily in the photosphere."

-- The Solar Spectrum