Slashdot Mirror

Joking aside, this really does have some interesting potential. Effectively this is a real nano-machine and I would love to read a little more, although I am lucky if I can understand 10% of what is in Nature!

It's not the temperature difference alone that determines the power, but the temperature difference times the heat flow. And I know of no theoretical limits to heat flow, although there are lots of practical problems...

Nature has the full scientific article. I don't understand most of it, but it does say "Thin-film thermoelements lead to large cooling power densities (PD)... We estimate a value of PD of 700 W cm-2 at 353 K and 585 W cm-2 at 298 K at the measured maximum cooling in superlattice devices compared to a value of 1.9 W cm-2 in the bulk device of Fig. 4a". That is, 700 watts/cm2 cooling at 70C (the max temperature for industrial-spec semiconductors), 585 at 25C (room temperature), and it's about 350 times as fast at pumping heat as the comparison thermoelectric material.

To actually use that cooling ability, you've got to somehow couple 700W/cm2 heat into one side and remove rather more heat from the other side. (Or to generate 700W power, you've got to couple more than 700W to one side and remove the waste heat from the other.) A TO-220 power transistor has an approximately 1 cm2 metal plate on the back to contact the heatsink; take a really big heatsink and really good thermal paste and really torque down the screw clamping them together, and it will handle almost 20W. 700W would fry the transistor core instantly, before the backplate even got warm. The coupling between a GHz Pentium and heatsink/Peltier refrig/fan must be better than this, but not THAT much better. Lots of luck!

By the way, anyone notice that the reporter doesn't know the difference between "efficiency" and "effectiveness".

a couple of them in fact. (look to the bottom of the page)

1) Even with all the freedom of the Machine Learning people's new model, the entrenched editorial board still places a biased bottleneck in the the propagation of information. The presence of an editor (or a publisher) is not equivalent to unbiased and effective peer review. In an edited journal, peer review often reinforces the 'old boys' network (I think Kuhn pointed this out in his book on Paradigms), and because journal space and reviewer's time are both limited, lots of good data never see the light of day (not only for this reason, but also for some of the reasons others have mentioned).

2) As for "Correctness", I would suggest that one thing added to the Slashdot model of academic publishing that would help make it work would be the posting of raw data. "Correctness" isn't the issue addressed in the peer review process. Nobody *really* knows whether results are "correct" (meaning that the experimentation was done properly) just by reading a paper, no matter how detailed (unless you work in a field that works on formal proofs rather than experiments). The review process weeds out the grossly incompetent stuff, and shapes up the other work to be more useful to the readership. "Correctness" is usually assumed: journal articles are so brief that the information necessary to establish correctness simply cannot be included. I say, put the whole damn data set on the internet, and anybody who wants to can dig around in the data to see whether what the author says matches up with the truth in the data. The only people who will dig around in the data are are those invested in the particular finding, but the end result is that for any given relevant finding, *somebody* who is skeptical will do a cross-check.

Recently a neuroscience journal (Journal of Cognitive Neuroscience) proposed a requirement authors submit their data to a massive neuroimaging database, see this essay. The debate was *very* heated, and JOCN eventually backed down (Those of you with journal access can see an editorial in the September 2000 issue of Nature Neuroscience for a rehash of the events). There were many reasons for the controversy, but one of the big ones was that people didn't want others to have access to their data -- authors want to be able to use their data for publishing new results before somebody else does. Really, though, authors don't want to let other people rummage around in their data because much of the research process involves putting a spin on things, and people not sharing the same views will not put the same spin the data.

3) An additional point of resistance to change is that Universities rely heavily on the current system for tenure and promotion evaluations. The currency in these is evaluations how many articles you've published, and how many of these were cited by others (and how frequently). It will take some work to figure out how to do this with a new system, but it should be possible, and at any rate this is a lesser goal than the one of truth-seeking.

4) Finally, the issue of credibility. From another post: "A comment made by a random AC on slashdot, in contrast, is not worth my [professional] time. There are just too many posts by too few knowledgable [sic] people." This is a good point, but it underestimates the power of the Slashdottish process: it would take a conspiracy of crackpots and cowards to cause a large enough wave of review-posts to give bad research any prominence. Slashdot's "threshold" function, even within a few hours of the original post, seems to work pretty well at weeding out the stuff I don't want to read; something developed for the purpose of academic research would be even better.

5) A related comment on the quality of peer review: In a Slashdottish system, the attractions of signed (i.e., not-anonymous) reviews would increase, because criticism of an article does not prevent it from being published. I would suggest optional signed reviews. In a Slashdot-like system, "signing" your review would give it more weight, perhaps (through cross-linking to your own work and to your other reviews) by establishing that you the reviewer are highly "cross-linked" and thus worth paying attention to. Plus, a Slashdottish system would naturally put a lot of pressure on people not to flame (and presumably the anonymous idiot-flames would soon die out).

General comment: The whole point of scientific publishing is to facilitate the search for and dissemination of truth. The rest -- journals protecting their territory, editors protecting their power, authors protecting their spin on their own data, and Universities protecting an easy method of performance evaluation -- is an unnecessary side show that impedes the primary purpose of uncovering truth. Let's have the authors post their papers and their data, submit them to the scrutiny of everyone else in the field (without the intervention of editors) and see what stands the test of time. The flaws in the system are the flaws of natural selection and democracy, of course, but that's just the way reality and people work. The truth will survive the process and it will come out more quickly and accurately with a bottom-up researcher-driven strategy than with any strategy driven by corporate profits.

There has been a vary interesting ongoing debate about the role of online access in publishing original scientific research that has been hosted by the journal Nature. It features articles by some vary high profile contributors (from our circles) such as Tim Berners-Lee, Richard Stallman and Tim O'Reilly although far more interesting are the opinions from members of the scientific communities directly effected by this issue.

--CTH

There has been a vary interesting ongoing debate about the role of online access in publishing original scientific research that has been hosted by the journal Nature. It features articles by some vary high profile contributors (from our circles) such as Tim Berners-Lee, Richard Stallman and Tim O'Reilly although far more interesting are the opinions from members of the scientific communities directly effected by this issue.

--CTH

There has been a vary interesting ongoing debate about the role of online access in publishing original scientific research that has been hosted by the journal Nature. It features articles by some vary high profile contributors (from our circles) such as Tim Berners-Lee, Richard Stallman and Tim O'Reilly although far more interesting are the opinions from members of the scientific communities directly effected by this issue.

--CTH

There has been a vary interesting ongoing debate about the role of online access in publishing original scientific research that has been hosted by the journal Nature. It features articles by some vary high profile contributors (from our circles) such as Tim Berners-Lee, Richard Stallman and Tim O'Reilly although far more interesting are the opinions from members of the scientific communities directly effected by this issue.

--CTH

There has been a vary interesting ongoing debate about the role of online access in publishing original scientific research that has been hosted by the journal Nature. It features articles by some vary high profile contributors (from our circles) such as Tim Berners-Lee, Richard Stallman and Tim O'Reilly although far more interesting are the opinions from members of the scientific communities directly effected by this issue.

--CTH

• Sanger Center project page with additional info for the data hungry.
• Press release on which the news articles are based.
• Nature Science Update's take on the news

...but was published in Nature 27 Sep 01.

As far as I'm concerned, I'd rather hear about it now, instead of back in June. Then it was just a paper presented at a conference. There's thousands of those, and I've presented a few myself.

Now, however, it's a paper that's been published in Nature. Can't say that I've ever had that distinction.

J.J.

You know, I think scientists are starting to wake up. For one thing, the equally prestigious magazine Nature had a short note recently about Dmitry's case, which was clearly sympathetic towards him.

Also, you have 27758 scientists signing the Open Letter of the Public Library of Science, and you've got physicists publishing pretty much all their material as pre-prints.

I don't think the open systems that science requires to function can co-exist with the closed systems wanted by the entertainment industry. If an open system exists, it can always be used to circumvent a closed system.

Now, it is easy to demonize "hackers" but it is harder to demonize scientists. Therefore, I think the first real battle will be over scientific publishing, and I want to be there when it happens.

Now, I don't think it will be a battle between scientists and artists, though the entertainment industry may try to portray it as such. The openness established by scientists and scientific publishing will be good for the whole of society, stimulate cultural diversity, and art will flourish along with science.

You know, I think scientists are starting to wake up. For one thing, the equally prestigious magazine Nature had a short note recently about Dmitry's case, which was clearly sympathetic towards him.

Also, you have 27758 scientists signing the Open Letter of the Public Library of Science, and you've got physicists publishing pretty much all their material as pre-prints.

I don't think the open systems that science requires to function can co-exist with the closed systems wanted by the entertainment industry. If an open system exists, it can always be used to circumvent a closed system.

Now, it is easy to demonize "hackers" but it is harder to demonize scientists. Therefore, I think the first real battle will be over scientific publishing, and I want to be there when it happens.

Now, I don't think it will be a battle between scientists and artists, though the entertainment industry may try to portray it as such. The openness established by scientists and scientific publishing will be good for the whole of society, stimulate cultural diversity, and art will flourish along with science.

The article refers to this article at Nature

Very interesting, this may enable for people in thrid world countries to have access to the best surgeons in the world. It may also allow operations on the ISS at some point. I'd expect to see developments where surgeons from multiple sites coordinate work on a single patient at a remote site.

The article refers to this article at Nature

Very interesting, this may enable for people in thrid world countries to have access to the best surgeons in the world. It may also allow operations on the ISS at some point. I'd expect to see developments where surgeons from multiple sites coordinate work on a single patient at a remote site.

Here are the articles the popular press cited (very awkward registration required). The "news and views" piece explains that astronomers previously thought the galactic core might be as much as 1500 times as wide as the event horizon of an equally massive black hole. The new observation indicates that it's no more than 20 times as wide.

Researchers are also targeting the insects that carry other vaccines. One possible way to fight malaria is to develop vaccines that "do harm" to mosquitos that suck them up in human blood, says Filip Dubovsky of the Malaria Vaccine Initiative in Washington DC. As yet, there are no candidate malaria vaccines that exploit mosquito saliva.

The existing treatments have adverse side-effects like creating resistant strains of malaria, are 'incompatable' with many users (a friend who lived in Kenya for a year called the weekly dosage "Friday night at the movies" because many people got hallucinations), or because they are just plain poisonous (e.g., painting the walls around an infected person with DDT).

There are other promising lines of attack on malaria as well, but this seems like it might be a good one.

"Robo-cup" (audio, requires player) by Lee Gutkind, National Public Radio, Weekend All Things Considered, 28 July 2001

"RoboCup 2001 Marks SGI's Second Year of RoboCup Federation Sponsorship" (press release), PR Newswire, 1 August 2001

"Robot Competitors Meet on a Soccer Field of Dreams" (free registration required) by Jeffrey Selingo, New York Times, 2 August 2001

"RoboCup: Where Bots Kick Butt" by Jason Spingarn-Koff, Lycos News, 2 August 2001

"Rush is on for 'HAL'-like computer to perfect A.I." by Winda Benedetti, Seattle Post-Intelligencer, 3 August 2001

"Robot world cup kicks off", BBC, 3 August 2001

"RoboCup 2001 boots up" by Helen Pearson, Nature Science Update, 3 August 2001

"Blutgrätschen ohne Blut und Beine", stern.de, 3 August 2001

"Roboter aus 23 Ländern tragen Fußballweltmeisterschaft aus", Net-Business Online, 3 August 2001

"RoboCup 2001, il calcio visto dai robot", Punto Informatico, 3 August 2001

"Building a better goalie (buzz, whir)" by Gregory Roberts, Seattle Post-Intelligencer, 4 August 2001

"Man and machine take the field" by David Olsen, Seattle Times, 4 August 2001

"Robots Storm the Soccer Field" by Maria Godoy, TechTV/Tech Live, 6 August 2001

Information about live Webcast of Botball finals (an event distinct from Robocup) on 7-8 August

Mathematicians have known for more than two centuries that the number is an infinite,
non-repeating decimal.

Definitely. This is why ISI and publishers including Elsevier put so much effort into lobbying congress, through the Software Information Industry Association, to cut funding to the PubScience database project. They've got their sights set on PubMed (as distinction from PubMed Central), next.

This is the sort of thing that you knew would have to happen. It's hard to day weather this iteration will be successful but eventually such a move will be nessecery in the scientific community.

If you missed the discussion, the journal Nature has an ongoing discussion on online scientific publication.

--CTH

This is the sort of thing that you knew would have to happen. It's hard to day weather this iteration will be successful but eventually such a move will be nessecery in the scientific community.

If you missed the discussion, the journal Nature has an ongoing discussion on online scientific publication.

--CTH

At least the article concludes that the GPL does NOT equal Open Source. Does it make sense that Gates/MS call Linux/OS/GPL cancerous and breaking to commercial companies than say it is healthy to the ecosystem? Cancer is healthy? Better send it in to Nature.com.

Clearly, it is also in the authors' interests (though not, one assumes, the publishers') to make the full text of papers as easily and freely available as possible, as highlighted in this article on the Nature site.

Surely therefore the logical thing to do is to expect the publishers by default to charge for the online full-text papers, either by journal subscription or pay-per-view; but to offer authors the choice of buying back the rights to have their full text made available free to the end-user, if the authors will pay an appropriate compensation, rather like the page rates currently charged by some journals. (The exact level of the additional page rates would be another base of competition between journals). As I think RMS pointed out in his contribution to the Nature debate, such rates would usually be quite small in comparison to the overall cost of the research, so with luck both funding agencies and universities would see it as in their own interests to insist on a policy of paying the price for free access.

Most of our enemies would see it most efficient to use prions.

These are what scientists think are responsible for mad cow disease, as well as the Kuru disease from Africa. Supposedly, if used as a biological weapon (which is years away, if even possible), they could be targetted toward specific ethnic groups and people with certain attributes. (Yes, each word in the above is a link to a resource.)

Many research groups are starting to make baby steps in this area. Here is one recent example published in Nature (requires registration):

here

The following is the abstract from an article in the journal Nature - very interesting. Give it a read!

You can read the whole thing on their website

RÉKA ALBERT, HAWOONG JEONG & ALBERT-LÁSZLÓ BARABÁSI

Many complex systems display a surprising degree of tolerance against errors. For example, relatively simple organisms grow, persist and reproduce despite drastic pharmaceutical or environmental interventions, an error tolerance attributed to the robustness of the underlying metabolic network. Complex communication networks display a surprising degree of robustness: although key components regularly malfunction, local failures rarely lead to the loss of the global information-carrying ability of the network. The stability of these and other complex systems is often attributed to the redundant wiring of the functional web defined by the systems' components. Here we demonstrate that error tolerance is not shared by all redundant systems: it is displayed only by a class of inhomogeneously wired networks, called scale-free networks, which include the World-Wide Web, the Internet, social networks and cells. We find that such networks display an unexpected degree of robustness, the ability of their nodes to communicate being unaffected even by unrealistically high failure rates. However, error tolerance comes at a high price in that these networks are extremely vulnerable to attacks (that is, to the selection and removal of a few nodes that play a vital role in maintaining the network's connectivity). Such error tolerance and attack vulnerability are generic properties of communication networks.

The following is the abstract from an article in the journal Nature - very interesting. Give it a read!

You can read the whole thing on their website

RÉKA ALBERT, HAWOONG JEONG & ALBERT-LÁSZLÓ BARABÁSI

Many complex systems display a surprising degree of tolerance against errors. For example, relatively simple organisms grow, persist and reproduce despite drastic pharmaceutical or environmental interventions, an error tolerance attributed to the robustness of the underlying metabolic network. Complex communication networks display a surprising degree of robustness: although key components regularly malfunction, local failures rarely lead to the loss of the global information-carrying ability of the network. The stability of these and other complex systems is often attributed to the redundant wiring of the functional web defined by the systems' components. Here we demonstrate that error tolerance is not shared by all redundant systems: it is displayed only by a class of inhomogeneously wired networks, called scale-free networks, which include the World-Wide Web, the Internet, social networks and cells. We find that such networks display an unexpected degree of robustness, the ability of their nodes to communicate being unaffected even by unrealistically high failure rates. However, error tolerance comes at a high price in that these networks are extremely vulnerable to attacks (that is, to the selection and removal of a few nodes that play a vital role in maintaining the network's connectivity). Such error tolerance and attack vulnerability are generic properties of communication networks.

Are you sure this is the first observation of Aurora on Jupiter? I mean when I worked as a research assistant in the Space Physics lab, I spent a fair amount of time doing image analysis on things that looked like aurora on Jupiter, and that was about ten years ago now. Infact, what I was looking at were maps of spectral emmissons coming of the plant. I also worked with images of ultraviolet light being emitted from the planet. If this wasn't an aurora, I don't know what is.

I think BBC got their terms confused. There's a fine book on the Jovian outer atmosphere and magentosphere called Time Variant Phenomenon in the Jovian System. While technical, this book is way cool and has some great images. Anyway, this is sort of a reference for researchers and grad students who study Jupiter. I believe it's out of print, but can be found at a decent University Library. It was self publisched by NASA and NSF. The point here is that aurora on Jupiter are familar phenomenon that have been studied for a quite a while. I'm not saying anyone understands it, but that's why they study it.

I wish my institution still had access to Nature so I could check the primary source. I think the news here is that a flare was observed. Maybe the big news is that the Hubble imaged it. I dunno. The project I worked on was based off a sounding rocket. It was a pretty cool setup. We'd put a telescope in the nose of small rocket. I think it was a Redstone, but I'm probably wrong. The thing would fly in a ballistic trajectory briefly leaving the atmosphere. During that brief time, our module would find the disk of Jupiter, focus on it, and record the spectra.

Waitaminute. Go to Nature and read the little write up they have. The BBC misreported it. This flare is wholly unlike anything yet seen. Different wavelength--visible! And, it's huge! Dang, that's impressive. The news here is that whatever is going on is not related to the well observed interation between Jupiter and IO. This event is due to an entirely different mechanism. It warms my heart to see an old prof of mine as a coauthor on the report.

Recently, however, our university's trial subscription to the online edition of the prestigious journal Nature and its associated monthlies expired. Our university decided to join with Harvard, Cornell, Princeton, and the University of California in boycotting what was deemed an untenably pricey subscription fee by the Nature publishing group ($30,000 CDN) for a service with significant restrictions in the timeliness of content. Our librarian's letter outlines our school's position on this issue. Nature's own site licensing policies are available here.

• Sheldon Schultz Quick Bio
• Research Group Page
• UsCD Press Release
• Nature Summary
• Space Daily summary - Excellent!

Check out the Vinny the Vampire comic strip

(Actually, I do not take them all that seriously, although such sites are an interesting read from time to time.)

With that much time for evolution, I doubt that there were only one or two varieties of humaniods. I imagine that there were many. and some just didn't make it.

Good to keep things in perspective, because good science is getting scarce in the public eye.

The Nature article was good, but over the head of someone not a specialist. The Nature Science Update posted above is a better read for those who do not want a headache trying to decipher the highly technical original

For those wanting something in between the hardcore Nature article and the mostly fluff CNN and MSNBC articles, here's a layman's version prepared by Nature itself. Check out Nature Science Update.

http://channel.nytimes.com/2001/03/08/science/08SU PE.html

now of course, Lucent has a website, with the press release here. The page with photos of the team can be found here on the bell labs site.

As Usual, the story was first reported in NATURE (NOTE - free registration gives some access, paid registration gives more)

It is mentioned in the actual research paper here. They explain the band structure can be modified by introducing an array of dislocations, which create a special kind of strain field in the crystal structure.

--

Actually, academics have created 100GHz transistors out of GaAs. 10GHz isn't that great compared to these ultra-fast ones

Here is the abstract from the nature website

Also available is full text and PDF of the paper.

The difficult part is that superpositions, which are the key requirement of qubits, are inherently destroyed when measurements are made. But some experiments, like the above, manage to sustain the superposition for a significant time, because the system is only weakly coupled to the measuring instruments.

--

I work for Physical Review Letters (and related journals at the American Physical Society) which is publishing the papers from the Ames, Iowa group. Interestingly enough, the first published paper (in the print journal today, available online since last week at http://link.aps.org/abstract/prl/v86/p1877) has set some new records in our office, in part thanks to increasingly all-electronic processing:

Manuscript received: 30 January 2001
sent to 2 referees: 31 January
Both referees report: 1 February
approved: 2 February
scheduled for an issue: 2 Feb
Updated manuscript received: 2 Feb
proofs available to author: 6 Feb
Author returned proofs (on the web): 8 Feb 2001

A final proof of the article available just over one week after being submitted, and going through a complete peer-review cycle!

More typically each step takes a week or two, though times have been generally improving lately.

But these new superconductors are pretty important!

Also interesting is that Nature has a nice "prepublication" look at the article on the original research, which they are publishing March 1 - Nature in the past has had an "embargo" policy preventing scientists from even talking to journalists about their work before the official publication date, but they've had this page up roughly since we published our related article online. The nature of scientific publishing is changing too here...

While it is very impressive, this discovery, it is important to note that a great deal of work will need to be done to make this a viable material.

A cursory glance at the pre-publish pdf shows that, even when zero field cooled (brought below transition temperature in the absence of a magnetic field, the field applied after the material is already cold), the MgB2 pellets created by Nagamatsu et al are fairly susceptible to flux penetration. Make no mistake, MgB2 materials will be perfected, and may compete with NbTi in the future, but they are still quite a ways off.

If you take the time to take a look at figure 4 of the writeup though, you will clearly see that MgB2 is superconducting, but Niobium Titanium wires have proven useful up to ~45T (tesla), whereas, in a 10 Oe (oersted) field, MgB2 ZFC was succeptible to roughly 1.2T.

Still a damned fine piece of work.

In Nature Magazine.

They measure things such as the number of fragments (fewer=better) and their lengths (longer=better) and estimated coverage of the genome.

There is also a less biased comparison over at the Nature website. I don't know if you can get to read it without a paid subscription though. Their findings are less controversial, saying that the statistics are similar for the two assemblies, but that the annotations (i.e. descriptions of what is actually there, comparison: A group photo with note on peoples names and their relationships) are better in the public version.

Lars
__

They measure things such as the number of fragments (fewer=better) and their lengths (longer=better) and estimated coverage of the genome.

There is also a less biased comparison over at the Nature website. I don't know if you can get to read it without a paid subscription though. Their findings are less controversial, saying that the statistics are similar for the two assemblies, but that the annotations (i.e. descriptions of what is actually there, comparison: A group photo with note on peoples names and their relationships) are better in the public version.

Lars
__

First, there's an interesting, relevant and relatively easy-to-read article by Jack Szostak and co-workers titled "Synthesizing Life" in the January 18, 2001 issue of Nature (vol 409, page 387). In this article they talk about the challenge of creating vesicles and effecting their replication, creating a molecular information-storage device capable of self-replication and coupling the vesicles to the information-storage/replication device in order to get a living/evolving system. Many of the questions raised in earlier comments are addressed. Most relevant to making life, or pieces of life, in space might be the issue of very low local concentrations? Article here [non-free login required (mrrr!)]. Alternatively, you could likely get a reprint from the authors directly by contacting them

Second, one of the more interesting things I remember Freeman Dyson saying was that he thought we should be looking for extraterrestrial life *outside* of gravity wells. That is, he thought it was more likely that things far-along enough to communicate with us would prolly not be sitting at the bottom of a well.

This "Liquid DNA" sounds like a kind of Ionic Liquid.

In most Ionic compounds (Like table salt), the strong attractions between the components means that the substances has a very high melting point. However, it's only fairly recently been discovered that if you use a very large, bulky cation, the melting point will drop, sometimes dramtically below room temperature.

Thus far, most applications have centered on using these substances as industrial solvents or catalysts. This is the first biological application I've ever heard of, apart from some attempts to use them as a solvent for enzymes.

You do not appear to have grasped either the seriousness of the problem or any of the views that you're trying to discredit. Perhaps that's why you haven't seen more 'substantive' evidence?

This is not about smog, or smoke, or anything you can dig up and look at. It's about the impact of industrialisation and, indirectly, capitalism on the equilibrium of the planet.

Which isn't an intrinsically bad thing, morally, except for the fact that we depend on that balance for our survival.

Global warming is not a synonym for climate change, it's just a particular example. The most severe problems we face are not simple sea-level issues but complex climatic phenomena like the direction and strength of the gulf stream and the migration of krill in the antarctic. These are the roots of the food chain and we're not going to like it much when they're cut. There are respectable, peer-reviewed studies (reg required) of these basic cycles which show them to be disrupted by our blundering.

There's a hundred-year lead time on this one. The changes we are seeing now have been accumulating for a century, and even if we all suddenly started conducting ourselves like a sane species instead of fouling our nest and flinging it around, we would still see terrible effects for decades.

So you're right, up to a point: the ability of people to fix this is highly questionable, their possession of the necessary insight even more so. But to deny that we are responsible for careless changes to the global ecosystem with unpredictable effects is the worst kind of head-burying.

You do not know what you are talking about. Climate change due to human activities absolutely HAS been proven, for any reasonable standard of 'proof'.

Some random links. Yes I know these aren't authoratitive primary sources but you can't deep link into the `Nature' site :(
BBC News
BBC News
paper in `Science'
Crowley in `Science'
(UN) IPCC
more U.N.
NASA
NASA
NASA
Nature
BBC News
New Scientist's excellent overview, ideal for clueless know-nothing^W^W getting a basic grounding in the major issues

Next time, try to avoid talking nonsense on a subject you know nothing about.
--
If the good lord had meant me to live in Los Angeles

The big difference in our solar system is that the gas giants are far from the sun, hence their moons are cold, which allows the Saturn moon Titan to keep a (mostly nitrogen) atmosphere. With higher temperatures, the gas molecules move faster, and the escape velocity is reached more easily, thus a larger gravity is required.

There was a paper by Darren Williams and two other authors in Nature back in 1997 which discussed the requirements for habitable moons. You can find a summary here. Basically it says that to keep an atmosphere, you need at least 0.12 the mass of Earth (i.e. five times the mass of the largest moon in the solar system, the Jupiter moon Ganymede).
Moreover, the authors argue that the moon must be able to remain geologically active for several billion years (to resupply carbon dioxide), which pushes the minimum mass up to 0.23 the mass of Earth. That would be twice the mass of Mars.

Sounds like a Nature article from a few months back

For those of you who are interested in learning more than what the Times gives, the full write-up is in this week's Nature (free registration required). I would link to it, but the way they have their CGI stuff set up complicates things. To find it, go to Nature's website, then follow the Contents link on the right, then go to this week's magazine; the article is titled "Neural engineering: Real brains for real robots", it's in the News and Views section, and it starts on page 305. Happy reading....