Hmmm. Did you analyze that?

So those ever-optimistic planetary scientists from the Phoenix mission have suggested that the photograph seen here indicates a layer of ice just under the surface. Now, just from the photograph I’m not sure how you could determine it was ice. I’d want confirmation, like, perhaps in the form of spectroscopic evidence or something along those lines. I’m sure they will do this sort of thing eventually, but the thing landed on Friday. I think it’s a little premature to claim that shiny patch under the lander is ice. I do know some folks who work on this mission (and a former student of mine spent some time working on it in grad school) and I’m sure they will be thorough. But let’s not jump the gun here.

In other space-related news, the Shuttle launched today which means the ISS will soon have a new, working pump for its one and only toilet. Not sure why that’s important? Well, let’s just say the pump operates the vacuum portion of the toilet. In earthbound toilets gravity performs the task that the vacuum performs.

Bill: Hey, Yuri, you left the cap off the Gatorade again.
Yuri: That’s not Gatorade.

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Volkswagon enters electric car fray

My second favorite automaker, VW (partially owned by my favorite automaker, Porsche), has finally decided to enter the electric/hybrid market, possibly as soon as 2010. VW has long been a provider of diesel cars that get great mileage and both VW and Porsche have made pretty efficient gasoline engines for decades (e.g. some 911s get almost 30 mpg and my 13-year-old Jetta with 245,000 miles on it still gets 34 mpg despite my less-than stellar driving and maintenance habits). It appears as if the technology will be a diesel-electric hybrid which would be cool since you could use fry oil from Mickey D’s as your fuel of choice. I have often dreamed of buying a mid-1980s Porsche 911 and turning it into a hybrid (I will also admit that Tesla is testing my Porsche/VW loyalty – lucky for the Germans I ain’t rich enough to buy a Tesla, though a sedan is supposedly in the works). Thing is, for those of you who don’t know this, I have a 180-mile round-trip commute so, with gas prices headed into the stratosphere, I’ll have to do something soon. Now if only I could get John Deere to get in on the act. I guess I could always retrofit my tractor with an electric engine…

Update: And, honestly, I’ve been wondering for several years now why, if these kids at West Philly High (a public inner-city school) can do it, why can’t the big boys? Turns out these kids have entered the automotive X Prize competition as well and Popular Mechanics has picked them as a top 10 contender (out of 64 entries).

Mistakes were made…

In the Forensic Physics course I’m teaching this summer one of the things we study is post-mortem body cooling. We look particularly closely at two papers that estimate various factors involved in body cooling. In one such paper, the authors give cooling curves – plots of temperature difference ratio versus hours after death. The temperature difference ratio is given by

R=\frac{T_{bt}-T_{et}}{T_{b0}-T_{et}}

where T_{bt} is the body temperature as measured at the site (brain, liver, and/or rectum), T_{b0} is the ‘normal’ body temperature (98.6ºF on average), and T_{et} is the temperature of the environment at the time the body temperature is taken.

But note that this does not seem to take into account fluctuations in environmental temperature. It seems like it would work just fine for a body found in a location with little day/night temperature variation (at that time). But what about cases in which there is a large swing in environmental temperature in a short period of time? For example, it dipped into the 50’s at my house last night but is supposed to get into the low 70’s today. Even moderate differences in T_{et} will cause time estimates to be off by quite a bit.

Of course, I could just see about finding a paper that addresses this issue, but, always up for a challenge (and armed with the suggestion of a student), I’m looking to see if there’s a way to estimate it by extrapolation. The seed of an idea is gestating in my head and we’ll see if it grows into anything. But it is curious that this issue is not addressed in the article. How did this clear peer-review? In fact, there’s a major error in the article too. Honestly it is likely a typo, but one equation is missing a factor of 1/1000 that is necessary for the numbers to come out right. Again, how did this clear both peer-review and the editing process? If I so much as forget to dot an i I get nasty referee and editor comments (ok, that’s a slight exaggeration, but only slight).

A disgusting world

As someone who has family members with autism-spectrum disorders – indeed, who has one himself – I find the fact that this happened to be utterly disgusting. I realize how disruptive students with these conditions can be, but I have seen similar situations handled with far more tact. It is a commonly held myth that people with autism-spectrum disorders do not exhibit feelings. Rather they exhibit extremes of feelings which means at times they can feel emotions more than the average person. How traumatic, then, might this have been for this student? Note that in the article, the teacher confirmed the story!

We have only just begun to understand these disorders. Most of the progress on understanding these disorders has come in the past 15 years or so and yet there is still a great deal of debate. There was a terrific article in Wired back in March that dispels even more myths about the condition. In recent years there’s also been a growing realization that ADD/ADHD is probably an autism spectrum disorder. Both are often seen in conjunction with OCD (obsessive compulsive disorder). The idea that any of these are due to vaccines is unproven. They are very clearly hereditary (one only needs to join my family for Christmas to understand this). I’ve included some articles on the link between ADD/ADHD and autism from a conference on autism sponsored by the Association for Behavior Analysis attended by one of my students who sent me these:

Richard Simpson (Kansas) on Asperger’s syndrome

Richard Foxx (Penn State) on scientifically treating autism

Bobby Newman (Room To Grow) on applied behavior analysis

Finally, some excellent books on both ADD/ADHD and autism are

Driven to Distraction by Hallowell and Ratey

The Curious Incident of the Dog in the Night-Time by Mark Haddon

Impersonation attacks

A few months ago I posted a note about some comments made in the Quantum Cryptography course I was teaching. Specifically it concerned the difference between a regular attack and an “impersonation” attack. In his reply, Matt Leifer pointed out that the “missing” link is the authentication of the classical channel shared by Alice and Bob (i.e. Alice needs to know she is actually talking to Bob). Authentication has always played an important role in cryptography, perhaps in no more poignant a way than during WWII.

I am presently reading a terrific book entitled Between Silk and Cyanide: A Codemaker’s War, 1941-1945 by Leo Marks who was the head of the codes department for the Special Operations Executive (AKA, the Baker Street Irregulars and originally viewed as the dirty water to the champagne of Bletchley Park until Marks overhauled the entire system). In it, Marks recounts that nearly the entire Dutch Resistance was captured and controlled by the Germans. Marks’ only suspicion that something was wrong came from the fact that no Dutch agents ever made mistakes in their coding while everyone else did. Not only did the famous German precision backfire in the case of Enigma (meticulous records that were eventually obtained by the Poles and Brits – plus some really good cryptographers) but it clearly backfired here too! Unfortunately it took Marks a long time to convince his superiors of this.

Putting Google maps to good use

Awhile back I posted a note about how creepy Google maps can be.  However, I have found a use for them after all, despite their creepiness.  I recently created a new course here at Saint A’s that deals with how physics is used in forensic science (so the course is titled Forensic Physics).  I then read this interesting article about how GPS units were being used to map accident scenes.  So, always up for a challenge, I decided to incorporate this with our study of automobile dynamics.  Specifically, we study how one can approximate travel speeds from skid marks.  So we headed over to an empty parking lot (after clearing it with public safety) and I created a nice set of skid marks on a slight rise (1º).  The students then measured the length of the skid marks, measured the slope, and took GPS readings (including elevation) for both ends of the skid marks.  While the GPS was not particularly relevant to this task (it is better suited for larger debris fields) they at least got the sense of how to incorporate it.  Back in the lab we brought up Google Maps and I showed them how to use the position finder and distance calculator to confirm their field readings and to show them how to map debris for an accident site.  It was pretty fun and now I feel less reticent about the existence of Google maps.

Maybe I should finish that Eddington book after all

Over at Incoherently Scattered Ponderings, there is an ongoing discussion that includes a dialogue on the h-index.  I have an absurdly low h-index, but when looking mine up (we don’t really pay any attention to them at my school) I was delighted to find a reference to my PhD thesis by Dean Rickles and Steven French in the introductory chapter to the book they co-edited with Juha Staatsi, The Structural Foundations of Quantum Gravity.  In a footnote related to Eddington’s “heroic effort” to develop a theory of quantum gravity, they refer to my thesis as “an almost equally heroic effort to render it comprehensible and relate it to modern concerns” (see p. 28).  Of course, Steven was the external examiner on my thesis and a major influence on my work (which, lo and behold, has come back round to quantum gravity via information theory).  So there is perhaps some bias there, but, hey, I’ll take what I can get.  Maybe I should buckle down and finish writing that Eddington book after all.  At least Steven would buy it and perhaps Dean.

Is a convincing argument even possible?

Well, under a rather confusing set of circumstances, my second law paper was rejected by PRA – a second time (even though I hadn’t yet made any changes and didn’t realize I had ‘resubmitted’).  In any case, I’ll be taking up Terry Rudolph up on his offer of assistance for the next re-write – and that will put the number of people assisting and/or commenting on this over the past few years into the double-digits, I think.

Anyway, my point isn’t to gripe again about the rejection, per sé.  Rather, I wonder if the basic idea even has a hope of getting published at all.  I know Terry thinks the fact that I derived the Cerf-Adami inequalities without reference to Markov processes is important enough to publish and I’ll certainly re-write the paper to focus on that.  But, the primary idea that I have been trying to get across is that the CF inequalities are a statement of the second law of thermodynamics, and therein lies the problem – no one seems to agree on what that law is!  And, yet, we continue to teach it to students as if we know it.

Consider some remarks from the first reviewer as well as those from a second reviewer they brought in to validate the first.  These should make it clear that physicists either have no idea what the second law truly is or simply can’t agree on it’s statement (which was partially the point of my paper).

Second Reviewer

“The second law of thermodynamics is much more that ‘just a strong statement on the behavior of probabilities’. This assertion in the introduction, even if found in ref.7, is so upsetting for many scientists, that could stop a good number of them at the out set, as it appears to be the case for the previous referee.”

Comment: This is an old idea (e.g. Eddington held this view) that still has a strong following (e.g. my Ref. 7 is to Dan Schroeder’s book and Schroeder knows enough to have also co-authored one of the definitive texts on quantum field theory).  Clearly I should have added a statement indicating I was using this ‘interpretation,’ but it is an interpretation that is commonly taught.  So, if it’s wrong, why do we teach it?  And, my entire point is that there is a problem with the second law of thermodynamics which this reviewer seems to validate by pointing out that “[w]hat I am trying to say is the second law of thermodynamics has been discussed and is being discussed by many, in various fields of science and engineering, and if it were only what the author says (or rather hints to), namely some inequality about probabilities, it would be quite strange that we are still here discussing it well over a century after its first statement.”  Then why, I repeat, does it still appear in published work by well-known and respected authors?

First Reviewer

“In the conclusions the author writes that ‘our definition of entropy needs altering,’ but this is nonsense, because we should not be surprised to see problems if a classical concept (Shannon entropy) is used to describe quantum dynamics.  All we need to do (to remove inconsistencies) is to use von Neumann entropies instead. The point you are raising was made by Brukner, who is acknowledged for discussions, so I find it hard to believe that this is a coincidence. But be that as it may, It is still nonsense to say that Shannon entropy needs to be amended. One should just stop using it in the quantum regime. The 2nd law is perfectly well described with conditional quantum entropies, as Cerf and Adami have in fact shown.”

Comment:  OK, here I really think the reviewer lets his personal views cloud his judgement.  First, if classical and quantum entropies truly do not describe the same (or at least related) phenomena, then don’t use the same freakin’ word to describe them.  Second, Caslav ain’t the only one who sees/saw a serious problem with the notion of entropy in general.  Carnap wrote a whole treatise on it (that was edited by Abner Shimony who is the ‘S’ in the CHSH inequalities, by the way, but perhaps philosophers can’t be taken that seriously)!  Third, how can one so blithely gloss over the quantum/classical dichotomy?  Somewhere they have to be reconciled with one another since they both describe the universe on different levels, and, at some point, there is a crossing from one into the other.  Fourth, von Neumann entropies can reduce to Boltzmann-Gibbs-Shannon entropies!  Therefore, they have to be related!  (See, for example, Sakurai on this topic.)

First Reviewer

“I know perfectly well what degree you have and what you teach. It is still not true that the ‘fundamental assumption of statistical mechanics is all accessible microstates are equally probable in the long run’. It is not true, and perhaps you should go back and reread a stat. mech. textbook. Again: “microcanonical vs.  macrocanonical.”

Comment: Perhaps I should have directly quoted the multiple stat. mech. texts that say these exact words.  The comment was in response to a comment I made in my reply (which I didn’t realize was taken as a reply – I was only asking for clarification on some points) in which I made it clear that I know statistical mechanics pretty well.  In fact, I know it better than I know a lot of other subjects since I am a former mechanical engineer who cut his teeth on thermo-fluid problems.  This is aside from the fact that I have been teaching it regularly for almost six years.

In any case, this makes me wonder if a convincing argument concerning the second law is even possible regardless of what it is related to, since it seems that no one can agree on what the second law is!  Perhaps Landau and Lifshitz did the smart thing by calling it the ‘law of entropy increase.’  In any case, this basic idea – that the CF inequalities are another statement of the second law (or a version of it, anyway) – seems so obvious to me that I am utterly blown away at the fact that, in two years, I have not yet found anyone who really believes in what I’m trying to do (even Barry admitted to being somewhat agnostic on the topic) except, perhaps, Ken Wharton, but no one believed in Ken’s work either until recently (he’s still having a rough go of it despite his work garnering him an invitation to spend a week at the Perimeter Institute). 

Kickin’ Karl Rove’s **s

I love it.  While I’m not a Democrat, I do loathe that slimeball Karl Rove with every fiber of my being and so I am in full support of John Conyers’ (D-MI) expressed desire to “kick his a$$.”  Rarely do we see such honesty in public officials.  I’ll at least give Bush credit for that – he speaks his mind (assuming he has one).

Update: And while I am not in full agreement with the following, it illuminates some of the scarier things in Bush’s sordid past.

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