tag:blogger.com,1999:blog-47487187105845273562024-03-13T12:48:09.510-07:00Stochastic Gain MediumA tube-mounted, ill-behaved amplifier for science and science policy.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.comBlogger28125tag:blogger.com,1999:blog-4748718710584527356.post-25064422632912303032011-10-13T17:10:00.000-07:002011-10-13T17:18:25.545-07:00C and UnixA bit of code, and a single command:<br /><br />int main()<br />{<br />printf("Goodbye, world.");<br />}<br /><br />world# echo "Thanks!" |<a href="http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2011/10/13/BU6V1LHD7C.DTL&type=tech">ritchie</a>B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-38500173546047581752010-05-27T08:56:00.000-07:002010-05-27T09:09:02.974-07:00Using a ruler to measure the wavelength of light.Place a ruler on your desk--the metal kind is best, but even a wooden ruler will do--and shine a laser pointer at its finest scale at glancing incidence. A diffraction pattern should appear on the far wall. A ruler is a reflection grating.<br /><br />In the November 1965 issue of the American Journal of Physics, Arthur Schawlow published a <a href="http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=AJPIAS000033000011000922000001&idtype=cvips&gifs=yes">brief article</a> describing what a "lecture demonstration" of the possibility of measuring the wavelength of visible light with a ruler and presenting without derivation the formula relating the scale spacing on the ruler and the fringe spacing on the screen to the wavelength.<br /><br />The widespread availability of cheap lasers has made this feasible as a student lab, or even as cocktail-party fare. I wouldn't recommend going through the geometry needed to compute spacing between fringes at a party, at least not until everyone else has had two more drinks than you, but it's something that can be done by students in the small-angle approximation (as by Schawlow) or possibly, using a computer, exactly.<br /><br />I've had students measure their laser pointer's wavelength to within a nanometer of the specified value. Not bad for metrology done with standard office supplies!B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-41727784906386992092010-03-30T22:23:00.000-07:002010-03-30T22:38:43.922-07:00Can a biologist fix a radio?This isn't a joke about biologists, but rather the title of a fun manifesto on cellular signaling and control pathways: <a href="http://www.springerlink.com/content/k425638750234506/">Can a biologist fix a radio?</a>.<br /><br />Written with the characteristic Russian sense of humor, it notes the similarity between a radio and a cellular signal transduction pathway and has biologists trying to learn how a radio works and how to fix a broken one by first categorizing the components by appearance, then breaking some to see which stop the sound, smashing radios to see which parts end up near each other, etc. The author (Y. Lazebnik of Cold Spring Harbor Laboratory) argues that this approach does not apply to tunable components, that biologists couldn't fix a radio, and that a better language to describe cellular signaling is needed, so as to make the process quantitative and provide answers to the question "what to measure?"<br /><br />Giving a seminar today, <a href="http://bmcb.biology.arizona.edu/capaldi.html">Andrew Capaldi</a> noted that microarray techniques done well are like measuring voltages across the components of a radio. Things have come far since 2002, when Lazebnik's essay was first published.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-33535458169286708522010-03-23T17:50:00.000-07:002010-03-23T17:54:24.769-07:00Optical Tweezers 'BlogA subject far closer to my interest: There's now a <a href="http://opticaltweezers.blogspot.com/">Blog on Optical Tweezers</a>, reporting on interesting or exciting papers on optical micromanipulation and its applications.<br /><br />It's not only a useful news source for a professional: if you're a "layperson" unfamiliar with this (not well-publicized) set of techniques, dive in. Any starting point on the 'blog will do.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-83155022563541119722010-03-23T01:35:00.000-07:002010-03-23T12:48:46.476-07:00Meyer's underwhelming response.Warren Meyer, the soi-disant "<a href="http://www.climate-skeptic.com">Climate Skeptic</a>", has <a href="http://www.climate-skeptic.com/2010/03/is-it-wrong-to-apply-a-simple-amplifier-gain-mental-model-to-climate.html">responded</a> to my <a href="http://stochasticgain.blogspot.com/2009/12/on-warren-meyer-and-feedback.html">earlier post</a> criticizing <a href="http://www.climate-skeptic.com/2009/06/its-all-about-the-feedback.html">his discussion of feedbacks</a>. The response is largely a combination of Bart Simpson ("I didn't do it nobody saw me do it you can't prove anything") and the government of Orwell's Airstrip One ("We have <i>always</i> been at war with Eastasia.") but ought to be examined further. Thanks go to Meyer and whoever on the LPAZ Diss and Cuss listserv (Mike Renzulli?) pointed him here; any traffic is good traffic.<br /><br />As of last week, Meyer is writing:<blockquote>First, I don’t remember ever claiming that climate models used a straight feedback-amplification method. And I am absolutely positive I never said GCM’s use feedback fractions. I would not expect them to. This is a total straw man.</blockquote> But in his original post (linked above), he wrote:<blockquote>In my video and past posts, I have tried to back into the feedback fraction f that <b>models are using</b>. I used a fairly brute force approach and came up with numbers between 0.65 and 0.85. It turns out I was pretty close. Dr Richard Lindzen has this chart showing the feedback fractions f <b>used in models</b>,...</blockquote>(Emphasis mine.) A year ago, Meyer was incorrectly claiming that climate models used a feedback fraction 1/(1-f). I have to give him credit for getting it straight between now and then, but now, in his response to me, he denies ever having had it wrong, as though I was just making things up about him. Not cool. A lawyers' trick as old as the hills, but I'd like to think that this isn't court and more gentlemanly standards apply.<br /><br />He goes on. <blockquote> am using a simple feedback amplification model as an abstraction to represent the net results of the models in a way layman might understand, and backing into an implied fraction f from published warming forecasts and comparing them to the 1.2C non-feedback number. Much in the same way that scientists use the concept of climate sensitivity to shortcut a lot of messy detail and non-linearity...(By the way, it is not at all unusual for mainstream alarmist scientists to use this same feedback formula as a useful though imperfect abstraction, for example in Gerard H. Roe and Marcia B. Baker, “Why Is Climate Sensitivity So Unpredictable?”, Science 318 (2007): 629–632 Not free but summarized here.)</blockquote><br /><br />Yes, feedback is sometimes convenient to discuss. The Roe and Baker paper--which I've probably linked from this 'blog three times already--even makes use of it as an _input_ of sorts. (An aside: Meyer calls Roe and Baker "alarmist scientists". I challenge him to point out just what is "alarmist" about their analysis, to explain where a special "alarm" assumption enters their analysis. "Alarmist" is a smear and nothing but a smear. It implies something about scientists' <i>methodology</i> that isn't justified by the contents of their work.) Rather than perform a Monte Carlo analysis (such as the parametric bootstrap) to estimate uncertainties of the GCMs directly, Roe and Baker take the GCMs' <i>effective</i> feedbacks as input for their own analysis and ask, given an assumption that the error of these feedbacks is Gaussian with certain hypothetical variances--see the paper!--what uncertainty would temperature have in an amplifier-feedback framework? But as Meyer now notes, the GCMs don't take feedbacks as inputs. He was wrong last year, he is correct now. That's OK.<br /><br />Or perhaps not:<blockquote>The author is essentially challenging the use of Gain = 1/ (1-f) to represent the operation of the feedbacks here. So let’s think about if this is appropriate. Let’s begin with thinking about a single feedback, ice albedo. The theory is that there is some amount of warming from CO2, call it dT. This dT will cause more ice to melt than otherwise would have (or less ice to form in the winter). The ice normally reflects more heat and sunlight back into space than open ocean or bare ground, so when it is reduced, the Earth gets a small incremental heat flux that will result in an increase in temperatures. We will call this extra increase in temperature f*dT where f is most likely a positive number less than one. So now our total increase, call it dT’ is dT+f*dT. But this increase of f*dT will in turn cause some more ice to melt. By the same logic as above, this increase will be f*f*dT. And so on in an infinite series. The solution to this series for a constant value of f is dT’ = dT/(1-f) … thus the formula above.<br /><br />So the underlying operation of the feedback is the same: Input –> output –> output modifies input. There are not somehow different flavors or types of feedback that operate in radically different ways but have the same name (as in his Mustang joke).</blockquote>Let's call the long-term, steady-state global mean temperature anomaly "dT'" as Meyer does. Let's call the long-term, steady-state global mean temperature anomaly were the CO2 concentration to change and everything else to remain constant dT. Let's call the CO2 concentration C. The only general thing we can say about the relationship of these variables is dT'=F(C) where F denotes "function". Now clearly dT=G(C) where G is some other function. We certainly can't get as specific as Meyer and state "F(C)=(1+f)*G(C)" where f is some constant. <br /><br />Meyer at some point concedes this, claiming that feedback being linear is but a useful approximation. Maybe our difference is a mere misunderstanding, caused by one of those vocabulary differences between scientist and engineer.<br /><br />Nope. There's way, way more to our difference. One of us is being "slippery" about the past words of both himself and others. He continues, further down:<blockquote> I used one chart from Lindzen, and it wasn’t even about feedback</blockquote>. The chart on his <a href="http://www.climate-skeptic.com/2009/06/its-all-about-the-feedback.html">original post</a> is taken, with attribution, directly from Lindzen, and it's all about feedback. If Meyer had trouble figuring out to what I was referring, he need only have followed the link in my post--right back to his! <br /><br />When Meyer wrote that original post, he remarked:<blockquote> Dr Richard Lindzen has this chart showing the feedback fractions f used in models, and the only surprise to me is how many use a number higher than 1 (such numbers imply runaway reactions similar to nuclear fission).</blockquote><br /><br />His spider sense was really tingling there--feedbacks greater than 1 should be surprising, whether or not they are "used" by models--but he failed to come to the correct conclusion. Lindzen couldn't possibly have inferred feedbacks greater than 1 using the method discussed in the source lecture, feedbacks greater than 1 are nonphysical and Lindzen's chart was horseshit. Instead of, as a "skeptic" would, calling a pile of shit a turd, Meyer used it in the OP to claim that the GCMs are wrong. Forgive the scatology, but that's like dividing the pile in two and knocking the halves together to try to make fire.<br /><br />A short digression. In the recent post, Meyer declares: <blockquote>I have not modeled the climate, but I have modeled complex financial, economic, and mechanical systems. And here is what I can tell you from that experience — the more people tell me that they have modeled a system in the most minute parametrization, and that the models in turn are not therefore amenable to any abstraction, the less I trust their models. These parameters are guesses, because there just isn’t enough understanding of the complex and chaotic climate system to parse out their different values, or to even be clear about cause and effect in certain processes (like cloud formation).</blockquote> This is an attitude common among climate denialists (even of Meyer's "it's happening and anthropogenic but climatologists have it all wrong" sort): what we working scientists call "effective" theories are somehow better than those with microphysical underpinnings. "I don't trust theories with realistic foundations because there's too much going into it, too much to read, and I don't want to trust that e.g. parametrizations in the literature that have withstood the test of time or those realistic foundations themselves are reasonably good." Transplant this way of thinking to e.g. neuroscience (not my field, but it keeps coming up because it's so accessible) and you get someone who is OK with the Hodgkin-Huxley model of action potential propagation (excellent science, BTW, especially given what little was known about the membrane back then) but balks at attempting to build such things up from known behavior of voltage-gated ion channels. I guess we have stereotypes because they're approximately true, but if we take them too seriously...well, I doubt that Meyer has serious objection to models of the neuron's cell membrane built up from what is known about single ion channel behavior. It's downright wild to call the parametrizations used in GCMs "guesses", but that's a matter for another time.<br /><br />Back to the point. I don't like working discussions of people's honesty into discussions of science. I really don't. But here it's only in response to being, in effect, accused of being dishonest myself. I just caught Meyer claiming--despite my link to his original post, and despite the link to Lindzen in his, that he never claimed that climate models "use" feedbacks, that I'm making a straw man argument, and that he didn't use an obviously bad analysis of feedback from a set of Lindzen slides as reference. It's "I don't know what Kalafut's talking about, it's a straw man argument!" in a way to make me seem like a liar and a loon. Again: Not cool. Mr Meyer: you've been caught. Perhaps your understanding of the science has matured in a year, but that doesn't retroactively correct your past blunders nor does that retroactively turn criticism of your past statements into straw-man arguments.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-1934851897864590442010-03-18T19:04:00.000-07:002010-03-18T19:05:37.936-07:00The Homeopathy Challenge<a href="http://encyclopediadramatica.com/Alternative_Medicine">From Encyclopedia Dramatica</a>:<blockquote>Whenever you encounter someone who buys into Homeopathic cures, you should give them the Homeopathic Challenge. Tell them to induce severe Alcohol Poisoning by chugging an entire bottle of Everclear (a 190 proof grain spirit) in one go. They should then place 1 drop of Everclear in a liter of distilled water, mix it up, and dilute it down further as necessary. If Homeopathy really works, this solution should cure the Alcohol Poisoning and save the guys life. Obviously drinking an entire liter of such potent liquor will mean death without medical treatment, so you can use this to entice the retard to prove once and for all Homeopathy works. </blockquote>B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-16916401566790400952009-12-06T21:52:00.000-08:002009-12-06T22:28:58.047-08:00On Warren Meyer and feedback<a href="http://goldwaterstate.blogspot.com/2009/11/few-words-about-warren-meyers-bona.html">Elsewhere</a>, FOTB Martel Firing asks for my take on a bit of <a href="http://denialdepot.blogspot.com/">'blog science</a>: (would-be) "Climate Skeptic" Warren Meyer's thoughts <a href="http://www.climate-skeptic.com/2009/06/its-all-about-the-feedback.html">regarding feedback</a>. The request is as follows:<br /><blockquote>Ben,<br />I must admit that I'd find the papers beyond my knowledge as I remember nearly nothing from HS Chemistry decades ago. But thanks for the offer.<br />My point was simply that I think you were a bit harsh on Meyer, who although he has a good scientific/engineering education admits to being an amateur -- kind of like Benjamin Franklin and thousands of other amateurs who kept meticulous climate records before there was a single climatologist. For example, the world-wide effects when Krakatoa blew up in 1883 were chronicled in great detail mostly by amateurs. (See: Krakatoa by Simon Winchester)<br />If you want to refute Meyer's argument about AGW, I'd really like you to respond succinctly to his questioning of positive feedbacks needed to justify the catastrophic AGW climate models, e.g. what is the source of the positive feedbacks assumed by the models and what physical phenomenon and measurement thereof justifies a theory or run-away temperatures? (Less than 200 words, please, and no math. Thanks.) (...) See http://www.climate-skeptic.com/2...e-feedback.html and be sure to review the links therein, including the video.<br /><br />The "no math" request is a plea for a reason for the claimed positive feedback which seems rare in nature.</blockquote><br /><br />200 words is a bit short for such a big lump of errors, and to address feedback without math is a bit like trying to make a baby without using testicles, but I'll give it a go, anyway, with the caveat that I don't usually have patience for video, especially for video from people who can't get things right in the appropriate medium, which is writing, so the following addresses only the text. Here goes:<br /><hr><br />Naming positive feedbacks is easy. In paleoclimate, consider the effect of albedo changes at the beginning of an ice age or the "lagging CO2" at the end. In the modern climate, consider water vapor as a greenhouse gas, or albedo changes as ice melts. In everyday experience, consider convection's role in sustaining a fire. Consider the nucleation of raindrops or snowflakes or bubbles in a pot of boiling water. At the cellular level, consider the voltage-gated behavior of the sodium channels in a nerve axon or the "negative damping" of hair cells in the cochlea.<br /><br />On to the meat of Meyer's argument: he seizes on one word ("feedback") and runs madly, from metaphor to mental model. Metaphor: "like in an ideal amplifier". Model: The climate experiences linear feedback as in an amplifier--see the math in his linked post or in the Lindzen slides from which he gets the idea. And then he makes the even worse leap, to claiming that climate models (GCMs) "use" something called "feedback fractions". They do not--they take no such parameters as inputs but rather attempt to simulate the effects of the various feedback phenomena directly. This error alone renders Meyer's take worthless--it's as though he enquires about what sort of oats and hay one feeds a Ford Mustang. Feedback in climate are also nonlinear and time-dependent--consider why the water vapor feedback doesn't continue until the oceans evaporate--so the ideal amplifier model cannot even be "forced" to apply.<br /><br />Meyer draws heavily from a set of slides from a talk by Richard Lindzen before a noncritical audience. These slides are full of invective and conspiracy talk, and their scientific content is lousy. Specifically, Lindzen supposedly estimates effective linear feedbacks for various GCMs and finds some greater than one. The mathematics presented by Lindzen in his slides does not allow that, and he doesn't provide details of how such things even could be inferred. An effective linear feedback greater than one implies a runaway process, yet GCMs are always run for finite time, so there cannot be divergence to infinity. Moreover, as far as I know, all of the GCMs are known to converge once CO2 is stabilized.<br /><br />In short, Meyer has the wrong idea about models (they don't take an amplifier-like feedback as a parameter), the wrong mental model of feedback (feedback in climate is nonlinear and time dependent) and he relies on a situationally unreliable source for numbers.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-21262868336452700422009-12-06T20:54:00.000-08:002009-12-06T21:02:14.178-08:00Why climatologists need to start filing lawsuits.UPDATE: I'd prefer not to link Watts (because he's a gish-galloper), but his site echoes the <a href="http://wattsupwiththat.com/2009/10/01/response-from-briffa-on-the-yamal-tree-ring-affair-plus-rebuttal/" rel="nofollow">early version of Briffa's rebuttal</a> which may be useful while the CRU servers are acting up. Note that there's nothing important there that could not have been inferred from his paper. "No cherry picking--we used X algorithm from Y reference."<br /><br />Back in September, climate science gadfly/demagogue Steve McIntyre posted an extensive commentary on the <a href="http://post.queensu.ca/~biol527/Briffa%20and%20Keith%202000.pdf">2000 paleoclimate paper of Keith Briffa</a>, accusing him of cherry-picking Siberian tree ring data from the "Yamal" set. As readers of this 'blog are already well aware, there's no major scientific thesis of modern-day import (such as anthropogenic global warming) that hinges on paleoclimatology let alone on the rings of a handful of Siberian trees. Nevertheless (perhaps even predictably) McIntyre's commentary went "viral" in the right-wing blogosphere; within a few days the socially constructed truth of the Right was that:<br /><ol><li>the Briffa reconstruction was "debunked",<br /><li> that this meant that the anthropogenic global warming thesis was based on a "<a href="http://blogs.telegraph.co.uk/news/jamesdelingpole/100011716/how-the-global-warming-industry-is-based-on-one-massive-lie/">MASSIVE lie</a>",<br /><li>and that Briffa had engaged in professional misconduct to arrive at his result.</ol><br /><br />Briffa released a <a href="http://www.cru.uea.ac.uk/cru/people/briffa/yamal2000/">thorough reubuttal</a> (use the Google cache if you have trouble with CRU's web server); the whole crew at RealClimate played "what if" and <a href="http://www.realclimate.org/index.php/archives/2009/09/hey-ya-mal">explored the dependency of "hockey stick" reconstructions--and Briffas paper--on the Yamal data</a>. Neither misconduct nor a blunder turn out to have been made, McIntyre loses, Briffa wins, the story should end there, right?<br /><br />Of course not. Among climate denialists, no argument ever dies, because nobody--not even academic law professors--has the integrity to do intellectual due diligence, to verify a claim before passing it on. Thus yesterday Jim Lindgren of the Volokh Conspiracy gets to call Briffa "ethically challenged" and accuse him of the same professional misconduct that McIntyre's fans were accusing him of a few months ago, by a cut-and paste "<a href="http://volokh.com/2009/12/06/debunking-briffas-version-of-the-hockey-stick/">Debunking [of] Briffa’s Version of the Hockey Sticks</a>".<br /><br />Again, none of it sticks, and one gets the feeling that Lindgren doesn't have the intellectual wherewithal to determine whether or not any of it sticks in so technical a field (and who is Lindgren to declare that CRU are now outside the community of scientists?), but the accusations are made anyway, namely that Briffa is cherry-picking and that the data analyzed in his paper were from "datasets, researchers, and locations that he did not disclose"--that is to say that he lied in his paper about what data he was analyzing. Pretty serious accusations to be making so lightly!<br /><br />Maybe Lindgren stopped just short of libel and maybe he didn't--one would <i>think</i> he knows better than to cross the line--but it's clear that this is, unlike most disputes in science, not a dispute between gentlemen. Accusations of professional incompetence and misconduct, conspiracy theories in essence, are not what scientists toss back and forth at each other in pursuit of the truth. My thought are the following: Lawyers (like Lindgren) file libel suits over lesser matters. Climatologists are accused of professional misconduct or worse (think "hoax") over and over again, by prominent people like Lindgren, McIntyre, and other such right-wing commentators daily, to the point where it appears to be akin to the Marxist <a href="http://en.wikipedia.org/wiki/Propaganda_of_the_deed">Propaganda of the Deed</a>, a shaming, a "counting coup", an unfair tactic that has people believing that the accusations "must be true" because they are unanswered. The everyday punching bags--Briffa, Hughes, Jones, Mann, just to name a few--need to start identifying the easy targets, who are local and whose remarks are most clearly tortious, and start making them hurt. Reasonable people, gentlemen, would be stopped in echoing these libels by the rebuttals if not by their factual inaccuracy. The denialists aren't reasonable or decent people and they need to be dealt with in terms the unreasonable and indecent understand. Joe Schmoe made that accusation and settled out of court for X dollars" might stop the denialists from repeating their wildest personal attacks when mere rebuttals don't.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-44137003350930138662009-12-02T16:58:00.001-08:002009-12-02T17:00:25.232-08:00A cautionary taleDon't lose your lab notebook, or <a href="http://www.sciencemag.org/cgi/content/full/326/5957/1187-a">this</a> may happen to you.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-19482254590977354732009-12-01T16:31:00.000-08:002009-12-01T17:43:19.279-08:00Pissing in the meme pool, Climategate edition: "They keep their sources and methods secret!""Climategate" could be described largely as a combination of poor science reporting--think of what might have been were that credulous Washington Post reporter to have had even an infinitesimal epsilon of perspective!--and a "shotgun slander": spin the content of the e-mails, the codes, etc. in the worst way possible, see what you can get away with, and never, ever, retract a falsehood. That isn't to say that some of the criticism hasn't been judicious or constructive--'bloggers Will Wilkinson, Megan McArdle, Tyler Cowen, and Robin Hanson, among others, had very judicious things to say--but that's been drowned out by anti-science types who are unable to or refuse to distinguish good argument from bad.<br /><br />I suppose it's been improving. Last week "hide the decline" was the rage, followed by complaints that (gasp!) submitters of papers being allowed to suggest referees must be an evil conspiracy, and the Bizarro-world narrative that had concern for the integrity of the peer review process (e.g. the DeFreitas affair at Climate Research) was subversion of the peer review process. Now the complaint has settled on possible planned evasion of FOI requests and the supposed deletion of raw data from CRU servers.<br /><br />The gripe about FOI request evasion is possibly legitimate; that of deletion of other people's data from CRU servers, less so. If I had to identify a party that could be harmed by it, I'd identify the CRU itself.<br /><br />Suppose that the would-be "skeptics"--and I hate that term because it implies that everyone else is a bad scientist--decided to do something constructive (instead of producing the usual flood of obviously-wrong, long-debunked specious arguments) and attempted to duplicate one of the CRU temperature results. They have no reason to expect help from CRU--should scientists help people who incessantly libel them and look for cute-but-false arguments that their life's work is a stupid mistake?--but suppose that they find that following the published information in good faith, they can't duplicate the set. It's incumbent on CRU scientists, then, to publish clarifications or supplemental information that enables duplication. But deleting those files may be like throwing out lab notebooks: CRU might find itself lacking information necessary to duplicate their own results! It would seem that the only option would be retraction! That would be a coup for the "skeptics", one that IMO they would not deserve.<br /><br />But wait, you say: the "skeptics" couldn't possibly do this, because the CRU has kept both the raw data sources and methodology secret. Think about it for a minute: would the rest of the scientific community use the CRU results if this were so?<br /><br />The release of each CRU derived data set was accompanied by a peer-reviewed paper explaining the methodology and listing the sources. The CRU TS 2.1 temperature data, for example, were explained by an <a href="http://csi.cgiar.org/cru/PDF/mitchelljones.pdf">International Journal of Climatology article by Timothy Mitchell and Philip Jones</a>.<br /><br />From this article, someone who gets his hands on the same raw data should be able to duplicate the result. If the paper doesn't contain sufficient information to do this, it should not have passed peer review--explaining methods well enough to permit duplication is one of the universal standards for review, and complaints about this are common in referee reports.<br /><br />The existence of this paper and others like it doesn't keep the credulous "skeptics" from saying that everything is secret. <a href="http://www.haloscan.com/comments/studentliberal/7670191093042167954/" rel="nofollow">Libertarian 'blogger "CLS" is a prime example.</a> To quote his comments section (linked): <blockquote>They won't list a source for the data so you can't find it easily. And then you need to know how they massaged the figures, what assumptions they used, etc., in order to replicate their results or to find errors in the process, all of which is necessary before this can rightfully call itself science.<br /><br />As far as I am concerned these men took all their work and flushed it down the toilet. By deleting the original data and refusing to discuss how they massage the original data to get their final results, they remove their claims from "scientific theory" entirely. Science requires replication and scrutiny and they made both impossible. By doing so they themselves took their "findings" and moved them outside the realm of science entirely. If I were a warmer I'd be furious with them.</blockquote><br /><br />Clearly they are listing sources, yet CLS says "They won't list a source." Clearly their papers discuss methodology, yet this CLS says they "[refuse] to discuss how the 'massage' the original data".<br /><br />If nothing else, this illustrates that denialist, faux-sceptic, anti-science, or whatever you call it methodology hasn't changed: Tell the truth about the state of the science when it is convenient, lie about the state of science when it is not. Make false accusations about others at your leisure. The primary technique shall be Just Making Stuff Up. And when called on it, never explain, retract, or apologize.<br /><br />"Climategate" has revealed interesting things about science politics and the need for a few things in climate science if not in science as a whole to change. But it has also made clear that the "skeptics"'s moral bankruptcy is on par with their scientific illiteracy. Their near-universal participation in the last week's lies--and not a peep from any of them speaking out against their fellows!--shows that this is not limited to a few bad eggs like Ian Plimer.<br /><br />If you don't know something, Just Making Stuff Up, especially about the work of others, should never be an option.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-58371626660388638912009-11-23T15:06:00.000-08:002009-11-23T16:03:31.250-08:00I couldn't make that up if I tried!On Helium.com, an article heading:<br /><br />"<a href="http://www.helium.com/knowledge/5425-why-is-global-warming-damaging-the-ozone-layer">Why is global warming damaging the ozone layer?</a>"<br /><br />Excepting that some anthropogenic greenhouse gases (think Freon...) are also ozone depleting, the two matters are unrelated. There's certainly no simple causal link between AGW and ozone depletion. It is possible, as a pure hypothetical I haven't spotted in the literature, that the climate change associated with AGW will affect stratospheric air currents (at the poles or elsewhere) in such a way as to enhance or diminish ozone depletion, but that sort of thinking is probably not what is at work here.<br /><br />Over a decade ago, while still in high school, I wrote in to the editors of a several-book introduction to economics recommending that they remove a phrase "and greenhouse gases are still depleting the ozone layer" from a discussion of externalities. I didn't understand how anyone could confuse these two very different problems--the mistake is inconceivable, not one of those for which one can follow the thought process that led to the wrong conclusion.<br /><br />Strangely enough, Helium.com attracted three writers to this heading. One treats us to the denialist Gish Gallop, one notes that some greenhouse gases break down into free radicals in the upper atmosphere, and one merely states both problems. To their credit, neither made the connection. But someone on the Helium.com staff did. I'd like to put myself in his shoes mentally, but I find it impossible. That has depressing implications.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-33472624797978605822009-11-01T20:52:00.000-08:002009-11-01T21:02:47.858-08:00An ocean acidification referenceThe seemingly thorough lack of concern of Steven Levitt and Steven Dubner for ocean acidification in the geoengineering chapter of their recent Superfreakonomics has brought this once-obscure environmental problem to the mainstream consciousness.<br /><br />Of course,this means that denialist hoke is starting. ("They can't call it 'acidification' if the ocean is not turning to ACID. It's ALARMISM! RELIGION!!!!!1111!!ONE")<br /><br />Those who want to bring themselves up-to-speed on the science of global warming and the associated climate changes have things easy: the IPCC Working Group 1 summarized the literature up to 2007. The IPCC doesn't cover ocean acidification at all, as it isn't climate change. The Royal Society, however, has written a very fair <a href="http://royalsociety.org/displaypagedoc.asp?id=13539">review</a>, accessible to the lay reader.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-31029398695357694542009-08-14T22:11:00.000-07:002009-08-14T22:32:40.616-07:00Goodness of fit.From someone working in a bio-inorganic chemistry lab of fairly strong reputation, I heard of quite the outlandish abuse of statistics.<br /><br />Apparently, they were using reduced chi-square (the usual one, that assumes a gaussian distribution for the noise or of the uncertainty at each point) to fit curves to the data, and also for model selection, comparing models with different numbers of parameters. The number of parameters in the system is supposed to be physically relevant, in a way I don't recall. I don't want to identify the lab, anyway.<br /><br />Using reduced chi-square to do model selection is bad enough as it is: there's no reason to take a model with a higher number of parameters as being better just because it has a lower reduced chi-square. <i>How much lower</i> it should be is not clear.<br /><br />But the real trouble is: the reduced chi-square method comes, at least, with a sort of "warning light" for overfitting, that is, fitting models with too many free parameters. If the reduced chi-square is greater than one, one may or may not be overfitting. But if the reduced chi-square is less than one, and the noise in the data is independently distributed, it is an almost sure sign that one is overfitting, and filling in the noise.<br /><br />Have a look at the formula for the reduced chi-square statistic. For a perfect fit, what value does it converge to in probability? The answer jumps right out, doesn't it.<br /><br />Supposedly, at least one dissertation in this lab drew physical conclusions from fits for which the reduced chi-square was less than one. Several papers, as well, may have been published using this method.<br /><br />The social scientists and the climatologists are very good about their statistics; I'd like to think we're at least getting better about statistics in biophysics. But most of the physical sciences have a long way to come. The curriculum is already somewhat overloaded, but perhaps a course in practical statistics should be required of all doctoral students in the natural sciences, just as in the social sciences; such silly mistakes should be inexcusable. The mistake was not over petty matters such as the size of the error bar (a la the never-ending trouble some people have understanding the difference between noise standard deviation and standard error of the mean.) It directly affected categorical, conceptual conclusions.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-76189462890326656262009-04-06T21:51:00.000-07:002009-04-06T22:02:30.054-07:00Reading phylogenetic trees.As cladistics, facilitated by genetic comparisons and molecular-clock modeling, has become the dominant taxonomic method, the phylogenetic tree diagram has become nearly ubiquitous, but little explanation is given for its meaning. Where the branch points occur along one axis has meaning; placement on the other axis is a matter of taste.<br /><br />In a 11 November 2005 short article in <i>Science</i>, entitled <a href="http://www.sciencemag.org/cgi/reprint/310/5750/979.pdf">The Tree Thinking Challenge</a>, David A. Baum and Susan DeWitt Smith of the University of Wisconsin, and Samuel S. S. Donovan at the University of Pittsburg present a simple phylogeny and ask the reader to, based on that information, determine which of two critters is more closely related to humans. Take their <a href="http://www.sciencemag.org/cgi/data/310/5750/979/DC1/1">quiz</a> and see how you fare. If you get it wrong, the article--a very quick read--will set you straight and establish a good habit.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-25304893600190795212009-03-17T22:14:00.000-07:002009-05-05T14:39:27.104-07:00A recommended climate lecturer.<a href="http://pjk.atmosp.physics.utoronto.ca/">Paul Kushner</a> of the University of Toronto gives a truly outstanding hour-long introduction to climate modeling for the scientifically literate audience, managing also to slip in some of his current work, for illustrative purposes, near the end.<br /><br />I got a chance to sit in on it earlier today, while visiting Stanford University. I recommend him highly as a speaker, if you get the chance to invite him.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-61500136783561706812009-01-28T23:04:00.000-08:002009-01-28T23:45:51.581-08:00Journalist error of least import.On page 48 of the February 2009 issue of <i>Saveur</i>:<br /><blockquote>A nonstick pan is our choice for frying eggs and delicate fish filets [sic]. The 10-inch <i>T-Fal Ultimate Fry Pan</i>, from the French company that pioneered nonstick cooking in the 1950s, is the sturdiest around. Unlike Teflon-coated pans, it has a hard surface, made of a plastic-based resin called PTFE, that is virtually scratchproof and stands up to metal utensils.</blockquote><br /><br />The last time I checked, <a href="http://en.wikipedia.org/wiki/Polytetrafluoroethylene">Teflon was an old trademark synonym for PTFE</a>. I doubt T-Fal printed this claim on its box and figure Saveur's staff writer made up some pitchman's nonsense to pretend to be insightful.<br /><br />Compared to when journalists botch diet advice or environmental news, this is of little import. But I'm still going to write a letter, because I'm that kind of guy.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-86165973223703409612008-10-13T23:04:00.000-07:002008-10-13T23:51:25.525-07:00Did a meta-analysis published in the Lancet really vindicate homeopathy?The audacity of con artists knows few limits. In response to my recent Epinions <a href="http://www.epinions.com/review/Oscillococcinum_Remedy_Twin_Pack_12_Tubes_Boiron/content_446479634052">beat-up</a> of Oscillococcinum, a "homeopathic" sugar pill made and marketed by French quack cure behemoth Boiron, Inc., a representative of the company, one Alissa Gould, posted fifteen studies which supposedly prove the efficiacy of homeopathy or Oscillococcinum. Some of these studies were merely low quality garbage published in faux journals set up to promote quackery (<i>Journal of Alternative and Complementary Medicine</i>", <i>British Homeopathy Journal</i>), others were inconclusive and more than one actually supported the opposite of what Ms Gould claims.<br /><br />The one that caught my attention was a 2005 study by Shang <i>et al</i>, <a href="http://linkinghub.elsevier.com/retrieve/pii/S0140673605671772">"Are the clinical effects of homoeopathy placebo effects? Comparative study of placebo-controlled trials of homoeopathy and allopathy"</a>, <i>Lancet</i> <b>366</b>, and not only because I was shocked that the editors at such a prestigious journal let the use of "allopathy" as a synonym for mainstream medicine make it to press. (Whether "allopathy" was ever practiced is questionable, but it is clear that modern medicine is not based on some tawdry "cure disease with its opposite" maxim.)<br /><br />Shang and co-authors compared 110 placebo-controlled trials of homeopathy and 110 matched trials of evidence-based medicine, finding a trend toward bias in small trials of both, but significant evidence from the large trials that conventional medicine has specific effects, whereas homeopathy is similar to placebo. The paper is a bit difficult to read--I can't think of another field in which those "funnel plots" are used--but worthwhile not only for its frank assessment of homeopathy but also as an exemplar of method.<br /><br />Take-home lesson?: Beware Boiron employees pushing studies: they don't limit their hucksterism to the sugar-pill trade.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-50967586139843857212008-08-08T16:56:00.000-07:002008-08-08T17:47:32.256-07:00The Double-Bind of the IncompetentAs Bertrand Russell once put it, the trouble is that "the stupid are cocksure."<br /><br />We've all encountered them: people who think a talk argument they just made up, be it regarding quantum mechanics, the origin of life, climatology, or (to pull an example from my e-mail box), numerological connections in cosmology, trumps the intellectual "heavy lifting" and rigor of scientists building on the work of previous scientists.<br /><br />It strikes us as hubris, or even dishonesty. As scientists we see this behavior not merely as being incorrect but as a manifestation of a moral failing. Perhaps that is so and perhaps it is not; regardless, a <a href="http://www.apa.org/journals/features/psp7761121.pdf">study</a> by Justin Kruger and David Dunning, published in the Journal of Personality and Social Psychology, shows this lack of insight to be universal among the incompetent.<br /><br />Kruger and Dunning had student volunteers (given extra credit) take the logic portion of the LSAT, a grammar exam, and a "test" in which their rating of the quality of jokes was compared to that given by professionals, and also rate their performance on each. On all three, the low performers assessed their own performance as being above average. Top quartile performers underestimated their own ability, but they revised their assessment after grading five others' grammar exams. The bottom performers gained no insight from grading their peers' exams; they were unable to recognize better work when they saw it!<br /><br />It may be "old news"--the paper dates to 1999--but it is particularly rich, with more insights than I've summarized here. Among other things, it provides some insight into the obstinacy of the armchair global warming denialist, HIV/AIDS denialist, or quantum-mechanics contrarian. Not only are they ill informed, but they are unable to recognize expertise. Read the <a href="http://www.apa.org/journals/features/psp7761121.pdf">full article</a> (which may be behind a pay wall) for more.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-76663250626642478652008-08-05T15:19:00.000-07:002008-08-05T15:25:49.910-07:00"We have foregrounded the redistributional dreams of "social justice" over heroic aspirations to discover, invent, and thereby create new wealth..."Peter Wood, of the <a href="http://www.nas.org/">National Association of Scholars</a>, has a <a href="http://chronicle.com/weekly/v54/i48/48a05601.htm">brilliant essay</a> in this week's <a href="http://www.chronicle.com">Chronicle of Higher Education</a> connecting American high culture's obsession with identity and diversity to the drought of native-born scientists and engineers.<br /><br /><blockquote>The science "problems" we now ask students to think about aren't really science problems at all...a society that worries itself about which chromosomes scientists have isn't a society that takes science education seriously.</blockquote><br /><br />This is bound to anger precisely those who deserve it. A defense of merit, achievement, and a call for culture to respect merit and achievement is long overdue.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-11746044774133030892008-08-04T13:31:00.000-07:002008-08-04T14:09:00.038-07:00What's happening to Bangladesh?Hearing climate contrarians called "skeptics" is, to my ears, like nails on a chalkboard. Not only is there a tendency to fumble about looking for evidence or any argument, good or bad, in support of a predetermined conclusion--the opposite of a skeptic's behavior--but when it comes to evidence supposedly in favor of their position, they more often than not act more like simpletons.<br /><br />Consider the latest fad in the denialosphere, a <a href="http://news.yahoo.com/s/afp/20080730/sc_afp/bangladeshenvironmentunclimatewarming_080730134111;_ylt=Ai1fEIqHFVyfguECUfbGjKvPOrgF">pop report on land accretion in Bangladesh</a>. (Of course, the buzz is not about a scientific paper. Denialists don't usually read those, and tend to kick and scream when one insists they must!) It has been widely predicted that sea-level rise will inundate low-lying areas of Bangladesh, but, currently, sedimentation is adding 20 km^2 to the country, annually.<br /><br />To hear it from <a href="http://www.jennifermarohasy.com/blog/archives/003294.html">Paul Biggs</a> on Jennifer Marohasy's 'blog or <a href="http://freestudents.blogspot.com/2008/08/spoil-sports-ruining-our-apocalypse.html">CLS <!--Jim Peron--> at Classically Liberal</a>, this is proof that sea-level rise will not inundate Bangladesh at all, that the IPCC and unnamed predictors of "catastrophists" are wrong, wrong, wrong.<br /><br />This is nonsense, and it's so patently nonsense that one wonders if Biggs and CLS have any shame at all. Sedimentation and sea-level rise are competing effects: that one and not the other currently determines the sign of land-mass growth doesn't mean that it will always determine that sign. Let's take Paul Biggs' number as gospel for a second, that the IPCC predicts that 17% of Bangladesh will be under water by 2050. (What the IPCC predicts--and what it means for the IPCC as opposed to an individual group's paper to predict anything--is, of course, more complicated than this.) Bangladesh has an area equal to 134,000 km^2 according to the CIA World Factbook 17% of this is 22,780 km^2, far more than 20 km^2/year times 42 years, or even the Yahoo report's sanguine 5000 km^2 of "reclaimed" land.<br /><br />Comparing percentages is not, of course, the way to go about this problem; one needs a model of land accretion during a time of sea level rise. Neither Mahfuzur Rahman nor Maminul Haque Sarker, the scientists/engineers cited in the Yahoo article, are working is not working with one, and neither are the denialists. At worst, I'm being no more flimsy than the wannabe "skeptics"; the comparison is good for a rough estimate and I have better things to do with my time than change field of study.<br /><br />What's incontrovertible is that Bangladesh is already feeling the effects of rising sea levels, mainly through saltwater pollution of soils an aquafiers. See the <a href="http://www.ipcc.ch/pdf/assessment-report/ar4/wg2/ar4-wg2-chapter10.pdf">IPCC AR4 WGII</a> report for discussion and references. (I'd put 5-1 odds on the denialists not looking at the IPCC report at all!)<br /><br />But maybe I'm wasting my time even without changing field of study. CLS talks of a "Church of Saint Al" as though the tail is wagging the dog and climate scientists are taking marching orders from a mere popularizer. And he gives hints that, like Ronald Bailey prior to his <a href="http://www.reason.com/news/show/36811.html">Road to Damascus moment</a>, he's choosing a position on a scientific question based on what he wishes public policy to be, a dishonest practice. To quote:<br /><blockquote>Well that technology costs money and that means an improved economy and that means more carbon emissions so that can’t be allowed.</blockquote><br />Yep, it's the usual Bircher-esque paranoia, the party line from glibertarians who talk a lot about free markets but lack the imagination to put such markets to use: Improved economies mean more carbon emissions, economic growth can't be carbon-neutral or carbon-negative or happen in a cap-and-trade framework. You can either have economic growth or you can stop fouling the nest. Want prosperity? Then take unlimited global warming and ocean acidification.<br /><br />Now there's a teenage pinko's dream argument! "Capitalism and economic growth can only survive by fouling the nest."B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-89592781566473966212008-07-09T22:32:00.000-07:002008-07-09T23:18:48.121-07:00A serious deficiency in the introductory physics syllabusWith one lecture left in my non-calculus "College Physics" summer class, I gave the students a choice of covering oscillatory motion and sound or free energy with two applications to biological physics. The vote was unanimously for the latter.<br /><br />To my surprise, their textbook (the latest edition of <i>Sears and Zemansky's College Physics</i> by Young and Geller) has no mention of free energy, nor do the six other introductory physics textbooks (calculus-based or not) on my office shelf.<br /><br />A "water cooler poll" shows that nobody teaches about free energy in their introductory class. One grad student said he didn't see the topic at all as an undergrad! We teach students the Second Law of Thermodynamics, but not any of its practical consequences. Stock homework problems consist of ridiculous irrelevancies such as computing entropy produced by a falling parachutist.<br /><br />Free energy is perhaps the most useful idea we could teach life-science majors, and it provides a foundation for understanding chemical kinetics and entropic forces such as osmotic pressure, polymer elasticity, and the hydrophobic effect. Most of them hear it as a term in their general chemistry class, and even use it to predict the direction of chemical reactions, but they'd have to take physical chemistry to really begin to understand it.<br /><br />Could someone please explain to me why it's so universally absent from the syllabus as to be excluded from textbooks?B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-14862101819412857502008-06-20T17:00:00.000-07:002008-06-20T17:21:09.149-07:00Toward market control of agricultural runoff."Way back in the day", when I was still seemingly suffering from or perhaps just getting over the loutish aversion to environmentalism that free-marketeers catch like the flu, I <a href="http://web.archive.org/web/20010221214903/liberty-news.com/weekly/02_12_01.html">remarked on Dani Wenner's long-defunct liberty-news.com</a> (revived thanks to <a href="http://www.archive.org">archive.org</a>) about the inability to rein in the Gulf of Mexico's <a href="http://zp9vv3zm2k.scholar.serialssolutions.com/?sid=google&auinit=NN&aulast=Rabalais&atitle=Hypoxia+in+the+Gulf+of+Mexico,+aka+%E2%80%9CThe+Dead+Zone.%E2%80%9D&title=Annual+review+of+ecology,+evolution,+and+systematics&volume=33&date=2002&spage=235&issn=0066-4162">Dead Zone</a> through traditional means like emissions bans or the tort process, noting that perhaps some market-based solution could be brought to bear.<br /><br />I lost sight of the issue between then and now, until the <a href="http://www.nature.org">Nature Conservancy's</a> newsletter brought it back to my attention. That ever-innovative group, having concluded a paired-watershed study exploring different means to buffer waterways, has begun a pilot program which may be a major step toward the institution of markets in wetlands' <a href="http://en.wikipedia.org/wiki/Ecological_goods_and_services">ecological services</a>. To <a href="http://www.nature.org/magazine/summer2008/features/art24733.html">quote</a>:<br /><br /><blockquote>Faced with spiraling land-acquisition costs, the Conservancy is exploring how environmentally friendlier practices might be woven into existing farming operations. On the Mackinaw River, a tributary of the Illinois River, the Conservancy is carrying out a pilot program to test the feasibility of “nutrient farming.” Conservancy staff have built micro-wetlands at the ends of farm fields to catch nutrient-laden water before it reaches the river (in the wetlands, many nutrients are either taken up by plants or metabolized by bacteria and then released into the air).<br /><br />Nutrient farming could form the basis of a market modeled after an existing cap-and-trade system that has helped curb emissions of the pollutants that cause acid rain. Farmers could be paid for nitrogen and phosphorus they take out of the water with micro-wetlands, reducing the overall nutrient load flowing to the Gulf of Mexico.</blockquote>B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-81473092807429285652008-05-30T15:11:00.000-07:002008-05-30T15:18:03.976-07:00Ben Stein gets an F.It is a behavior we see rather often, usually in the context of the faux "debate" over anthropogenic global warming, and we ought start condemning it loudly until it is universally considered shameful: people who refuse to learn even the basics of a scientific theory not only feel entitled to have an opinion on it (as if that isn't bad enough!) but also to express that opinion publicly as though it is of equal merit, and to slander, implicitly or explicitly, the experts.<br /><br />Ben Stein and his writing and production team didn't bother to learn what every high-school graduate should know about the modern theory of evolution, rendering an already poorly-produced film not only wrong, but bad. My review of their film <i>Expelled</i> is now (belatedly) <a href="http://www0.epinions.com/content_431839940228">posted on Epinions.com</a>.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-3284796743743318972008-05-29T17:44:00.000-07:002008-05-29T18:25:01.331-07:00More insight on the Mentos eruptionThe June issue of the <i>American Journal of Physics</i> (the <a href="http://www.aapt.org">AAPT</a>'s flagship publication) contains a <a href="http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=AJPIAS000076000006000551000001&idtype=cvips&gifs=yes">report</a> by Tonya Shea Coffey of Appalachian State University on an undergraduate class project concerning one of the Youtube-era Internet's favorite kids' pranks: the <a href="http://en.wikipedia.org/wiki/Mentos_eruption">Mentos eruption</a>.<br /><br />Fruit Mentos and Mint Mentos were found to cause nearly equal emptyings of Coke bottles. Playground sand, among other things, was an adequate substitute. Diet Coke and Coca-Cola were nearly equally emptied by the Mint Mentos. Differences between Diet Coke and Caffeine Free Diet Coke were not clearly statistically significant.<br /><br />The Diet Coke-Fruit Mentos combination, however, produced the longest jet, followed by the classic Caffeine Free Diet Coke-Mint Mentos pairing. Further investigation by Coffey and her students showed from photographic evidence that aspartame reduces the work needed to form a critical bubble compared to plain seltzer water and that less work is needed to form a bubble in Diet Coke than in plain Coca-Cola. SEM study found that Fruit Mentos and Mint Mentos are nearly equally rough. Moreover, unlike a wax coating previously applied by the "Mythbusters", Fruit Mentos' coating dissolves rapidly in soda water. The researchers speculate about Mentos having a surfactant component but take no measurements.<br /><br />Fairly useless research, yes, but it gets students thinking about questions more subtle than those found in introductory textbooks, provides a means of introduction to surface science intersting to the common eighteen-year-old, and it's more practical than quite a bit of what ends up getting funded by DARPA.<br /><br />HT: <a href="http://www.chronicle.com"><i>Chronicle of Higher Education</i></a>B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0tag:blogger.com,1999:blog-4748718710584527356.post-50359956175117354342008-05-21T23:47:00.000-07:002008-05-22T00:12:02.882-07:00Porter Hypothesis now on sound footing, but does it apply to our world?As a physical scientist, I take a very negative view of the "talk arguments" still common in economics. Qualitative explanation is nice, but one cannot prove or argue anything with mere qualitative work. There is no qualitative scientific methodology.<br /><br /><a href="http://www.isc.hbs.edu/">Michael Porter</a> put forth a few years ago an idea with great appeal: under some circumstances, strict environmental regulations can be a win-win situation, both reining in the negative externality and inducing firms to eliminate waste and innovate, simultaneously increasing profits and R&D spending.<br /><br />More recent <a href="http://zp9vv3zm2k.scholar.serialssolutions.com/?sid=google&auinit=S&aulast=Ambec&atitle=A+theoretical+foundation+of+the+Porter+hypothesis&title=Economics+letters&volume=75&issue=3&date=2002&spage=355&issn=0165-1765">work</a> by Stefan Ambec and Philippe Barla puts this onto more solid footing. Note that the result is parameter-dependent. One would have to be a slob to say that the Porter Hypothesis (which really should now be called the Ambec-Barla Theorem) implies that there is no such thing as a bad environmental regulation.<br /><br />In a <a href="http://www.green.ecn.ulaval.ca/CahiersGREEN2005/05-05.pdf">recent review</a>, Ambec and Barla appraise the empirical evidence, and find that, while case studies can be found on either side, most of the time there are no Porter effects. Whether this is an artifact of the existence of pollution havens is one of many open questions.<br /><br />Win-win environmental regulations remain a tantalizing possibility but not an everyday reality. Perhaps we'll never be able to "have our cake and eat it too". Science, including economics, should inform our policy decisions to the greatest reasonable extent, but problems such as this make it clear that we'll always be caught with value judgements and shades of grey.B. Kalafuthttp://www.blogger.com/profile/15678386134174713187noreply@blogger.com0