Archive for May, 2008

Hmmm. Did you analyze that?

Posted in Uncategorized on May 31, 2008 by quantummoxie

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.

Volkswagon enters electric car fray

Posted in Uncategorized on May 31, 2008 by quantummoxie

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…

Posted in Uncategorized on May 30, 2008 by quantummoxie

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

Posted in Uncategorized on May 26, 2008 by quantummoxie

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

Posted in Uncategorized on May 24, 2008 by quantummoxie

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

Posted in Uncategorized on May 23, 2008 by quantummoxie

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

Posted in Uncategorized on May 21, 2008 by quantummoxie

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.