Blessed by the Potato

I am continually amazed at the lack of critical thinking in the general population and the media. I know that I’m a scientist and am therefore, you know, a perfect human being, blessed with capabilities mathematical and analytical in addition to citation searchical. Ok, maybe not quite perfect, but I will acknowledge that I perhaps possess a leg up in the critical analysis department due to inclination, training, and experience. Nonetheless, I’m amazed at some of the nonsense that floats around there in the ether.

For instance, the CNW “study” that just. won’t. die. Here’s where the big disconnect between common sense and reason lead to a meme that endures. The “study” in question claimed that a Hummer used less “energy” in its total lifetime (from design to daily driving to disposal) than Prius. That is something that goes against our common sense, kind of makes us sit up and take notice. Now, what’s supposed to happen is that one’s critical thinking and reason is supposed to kick in and say “hey, this really goes against our common sense: how does a vehicle that costs more money and uses more materials up front, and also uses more gas in an ongoing fashion, possibly use less total energy? I should check this out to see if it’s a neat factoid or total bullshit.” Then a quick fact-checking mission demonstrates that this is, in fact, total and complete bullshit and the thing dies there, and anyone who brings it up is mocked as a rube. Instead, the rubes pass it on without questioning it, and the illogic only serves to help draw attention to it. “Wow, Prius sucks, I’ve got to alert the Intertubes!” Whatever happened to extraordinary claims requiring extraordinary evidence?

I can forgive people for reading too much into patterns sometimes. For instance, nearly anyone who bothers to know anything about fuel economy knows that cars (regular cars — not talking hybrids here) are more efficient on the highway than in the city. But they have real trouble believing that driving slower on the highway saves fuel. After all, doesn’t going faster, like on the highway, save gas compared to going slower, like in the city? Ah, you point out, but there’s a point where the car is most efficient: 90 km/h, say. Going faster than that actually uses more gas. They think for a second, and the light goes on behind their eyes “Oh,” they say in a condescending way “I’ve heard that before, that’s why the speed limit was 55 in the States during the energy crisis. But that was for old cars. New cars are much better and can go faster.” Which, I have to admit, is exactly the right thought process, just the wrong result.

Likewise, for about 4 years there, housing was the best investment one could have: better than the stock market, briefly better even than oil. So you could forgive someone for lusting after a house, repeating nonsense like “priced out forever” and “renting is throwing your money away” or “real estate never goes down”. You might even forgive the same person who scoffed at the “payback period” for a hybrid car not running the same calculation for a house. The media didn’t even surprise me with their house porn and almost exclusively positive coverage of the bubble. I was, however, taken aback by the actions of our government, especially by easing the “margin requirement” (down payment) for a house. I know that they’re dumb promise-breaking neocons [ok, I won’t go there just now] and all, but still, someone should have known better. Then, as the real estate slowdown looks to finally be under way, a study comes out about the most over priced markets from UBC… and the markets it says are over-priced are not the ones people would think are over-priced. This is because of how they did their analysis: they included in their valuation a measure of how much a market has gone up since the last cycle: markets that went up more are not considered to be “bubblier”, but rather, more fairly priced in their estimation since they’re counting on further rapid increases. So the cities with the most rapid increase in prices are supposedly the ones that are less overvalued…

I recently chewed into Netbug about a post of his on environmentalism. He was arguing that man couldn’t cause global warming because, as a documentary that aired on BBC4 argued, we can’t compete with the sun. That’s just the sort of thing that’s great at misleading people (even otherwise smart people capable of Googling, like Netbug) — it has just enough ring of truth to it to make you believe it. This documentary makes a number of points which are true, but not important or worse, wrong-headed. Then it sprinkles in some minority opinions, a fair helping of conspiracy theory (global warming is a conspiracy by Maggie Thatcher to break the unions! Scientists take the dirty british money, but not the money of oil companies — no, if they did, they’d be richer and wouldn’t be doing some slumdog documentary film!) and some selective editing to sucker people in. Then Netbug finished off his post with a statement about how stupid the environmentalism movement has gotten with a clip from Penn & Teller about circulating a petition to ban water at some green rally, and all the people who signed it. Of course, that says less about the environmental movement in general, and more about people’s willingness to sign something they didn’t fully read or understand while at a rally.

So I was holding my hand up to a really bright light, and noticed that the light went right through my hand as though the bone wasn’t there. That diffuse red glow is nothing new, but what I noticed is that the blood vessels were blocking the light. “No way,” I thought, “blood can’t be more opaque than bone!”

Of course, that’s not really the case. Instead, it has to do with scatter: inside the tissue, the light isn’t going straight through like with something that’s actually transparent. Rather, the light is being scattered: bounced off molecules many times before making it out the other side. When something is highly scattered, then the light coming out often has very little relationship to the direction it came in, and it can even scatter around obstructions, such as bone. To get that uniform red glow, you need a fair bit of tissue, enough so that the average scatter length (how far the light can penetrate in the tissue before it finds something to scatter off of) is within the tissue.

With the blood vessels, they’re close to the surface, so when they block the light there isn’t enough tissue for the light to scatter around them (like there is for the bones), which makes them look opaque!

I know that the stock market posts have gotten out of control here lately, and I think it’s wearing on my regular readers (all three of them), since the comment rate has dropped off a cliff. For the first two years of BbtP, there were on average two comments per post (granted, one of those was probably me responding to the first comment), but lately it’s averaged four posts per comment, so to help get things back in balance, I declare this an open comment thread! Comment about anything you want, post any questions or requests you have, whine about whatever’s on your mind, or pimp your own blog (not that it’s going to help you, to be honest, but go ahead).

“If I were to stay up all night working on a paper, and drank 10 cans of coke (3 full strength, 7 Coke Zeros) to keep me going, would that amount of sleep deprivation and caffeine fuck me up?”

Yes. You would start bleeding from the nose around 7 am. Go to bed.

“Follow-up: at what point does one become too old for this shit?”

28.

We’re getting a new MRI unit here at work (actually, an MRI-PET-EEG hybrid imaging system). To make room for it, our old head-only scanner got the boot.

An MRI has a very strong static magnetic field (in the case of this scanner, 3 Tesla), about 60,000 times the strength of the Earth’s magnetic field (the magnetic field that lets you navigate with a compass). This field is on all the time (no matter how much TV and movie writers want to flip it on and off for plot gimicky reasons), due to a loop of current running through some superconductors (a superconducting electromagnet). To keep the superconductors superconducting, they are bathed in liquid Helium. To keep the liquid Helium from boiling off too quickly, it is in turn bathed in liquid Nitrogen (liquid Nitrogen is warmer than liquid Helium, but the difference is a lot smaller than the difference between liquid Helium and air, so the boil-off happens much slower, and liquid Nitrogen is much cheaper to boot, so it’s easier to keep topping up a large liquid Nitrogen buffer surrounding a small liquid Helium bath than to just keep toping up the smaller liquid Helium bath).

When something happens and we need to ramp down the field in the magnet, we “quench” it, venting the Helium and Nitrogen outside, letting the superconductors warm up, and then the magnetic field will come down as the current loop burns itself out (as heat due to the now non-zero resistance in the coil, and also by shunting the current away). Quenching is a very rare event, because it usually happens only when something bad happens and someone hits the emergency quench button (and we try really hard not to hit that button, as it can take a few weeks to get the MRI working again afterwards), or when a scanner has to be taken down to be moved. So our scanner move let us witness one of these rare events (though when I say “us” I don’t include myself, since I unfortunately forgot and didn’t show up to watch it in person, but I got the picture!). It’s just amazing to see that huge plume of condensation appear outside the vent — the now-boiled and thus gaseous Helium and Nitrogen are so cold that they condense not only the water vapour, but also the CO2 and Oxygen right out of the air.

I don’t really get it — there is a lot of fear and doubt out there about hybrid cars, a lot of people saying things to detract from the new technology. Some of it is pure bullshit, like the CNW study or the crap about the Sudbury moonscape. Some of it is selective accounting looking at the purely financial side of things, such as comparing a nicely equipped mid-sized car like a Prius to a bare-bones compact, or assuming that the price of gas won’t go up over the next 15 years, or that you’ll only own your car for 7 years at which point it will be worthless.

I can understand why some companies (cough, GM, cough) who are losing out on sales to hybrids might have an interest in sowing FUD, but I’m surprised that so many people out there seem to take it up without a second thought (how many times have I heard “oh, but the batteries will have to be replaced every 5 years”?!). Hybrids are a very promising technology and a vital step on our path to electric cars, and while rare until very recently on the ordinary streets of Canada, aren’t really all that new.

One of the latest rounds of fear-mongering focuses on the electromagnetic fields (EMFs) produced by hybrid cars, getting international attention in a recent New York Times article “Fear but few Facts on Hybrid Risk” which was linked to by the Consumerist. To quote from the article:

Kent Shadwick, controller of purchasing services for the York Catholic District School Board in York, Ontario, evaluated the Toyota Prius for fleet use. Mr. Shadwick said it was tested at various speeds, and under hard braking and rapid acceleration, using a professional-quality gauss meter.

“The results that we saw were quite concerning,” he said. “We saw high levels in the vehicle for both the driver and left rear passenger, which has prompted us to explore shielding options and to consider advocating testing of different makes and models of hybrid vehicles.”

I sent a message to Kent Shadwick, asking if he’d share his data so I could see what he considered “high” and whether that was a static (DC) field or a time-varying field measured. He did respond, and promptly, but only to say that he hasn’t shared the results anywhere, and that they hired an outside company to take the measurements using a rigourous procedure. He also said that he was looking into shielding solutions.

I have to say that this is really disappointing, and I think it shows the real lack of a decent science education in the general public that the New York Times ran this piece without even being able to say what the fields are or how that compares to the geomagnetic field, let alone whether there’s any risk from that. The field, if you will forgive the pun, of bioelectromagnetics is so controversial and so lacking in standards that it means virtually nothing to have one person say that something is “concerning” without knowing what their threshold for concern is. Some people are concerned by static fields that are weaker than the Earth’s magnetic field; some aren’t concerned about static fields at all until we get beyond the MRI level. Likewise with time varying fields: some people think that virtually any exposure should be eliminated, others think nothing of using microwaves up to the point where they cause protein denaturation or other fields up to the point where they start to heat the tissue. I have no idea what Kent Shadwick might find concerning, so even if he does have a respectable position with the school board (not some random nut falling asleep at the wheel) and even if he did hire qualified people to take good measurements with the proper equipment… his “concern” is not really newsworthy to me unless I know how his threshold of concern compares to mine.

Plus all this concern about magnetic fields in hybrids is really only part of the issue.

The question asked is always about the risks — we know, for instance, that ionizing radiation is something that can cause cancer and other health issues. However, if you have a broken arm or get a nasty bump on the head, you can be sure you’re popping in for an x-ray/CT no questions asked because there is a big benefit to those diagnostic tests that far outweighs the small inherent exposure. It’s really all about risk-benefit ratios.

So for the hybrid car issue, we have the question “what are the fields?” and we don’t even have a good answer to that, from which point some people fall into hysterics (up to selling their car). The real issue is then several steps removed: the Prius may have higher magnetic field exposures than other cars, and those fields have an unknown but probably small effect on human health, and that might outweigh the positive aspects of the technology.

One example used to show that pulsed magnetic fields can effect biology is the FDA-approved bone growth stimulator. I had the pleasure last week of listening to Arthur Pilla’s (one of the inventors of the electromagnetic bone stimulator) plenary talk in San Diego. He talked about the first use of the bone stimulator on a woman who had a fractured tibia just below the knee that hadn’t healed for 9 years, despite multiple bone grafts, etc. They had this theory that an electromagnetic stimulator might be able to stimulate bone growth, but they also knew that the fields would not be restricted to just the break, and that the knee itself would also be exposed. There was a real concern that the bone might grow wildly out of control and completely fuse the knee, but since this woman’s only other option was amputation, they gave it a try. The stimulator only caused bone growth where there was a break. My point is that it’s not quite so simple to say that induced currents will have an effect on tissue; they may have an effect on some tissue some of the time.

So ok, there might be some small risk with hybrids (though probably not). On top of that the benefits have to considered (fuel efficiency, emissions, safety…) One colleague off-handedly said that even if magnetic fields cause cancer, you’d probably be better off with a Prius because you’d be exposed to less gasoline from the gas stations and escaped vapours in your garage… another possible carcinogen. To save less fuel than switching to a hybrid would net, some people will tailgate (draft) semi trucks in their blind spot. That’s a behaviour with a definite and immediate risk — not of possibly getting cancer 20 years down the road, but of getting instantly killed by a tire blowout or sudden stop with zero space for reaction time. Of course, the risk of being turned into a red smear on the pavement is not a new type of risk to drivers.

The benefits of a Prius vs. a comparable conventional car are real and material. The risks are unknown, but probably negligible. Unfortunately people have such a fear of the unknown that they can blow it out of proportion in their decision making, and focus on their fears rather than the overall picture. Back to the York Catholic District School Board: as a scientist, I was a little disappointed that he wouldn’t share his results so that I could come to my own conclusions; however, I understand why he went to the effort of measuring the fields and looking into solutions — for an individual driver, the risk-benefit ratio is pretty clear: just buy the hybrid. For a school board fleet however, there are unions to consider, and a union will fuck up a school board over a perceived threat to its drivers, whether or not that’s a real concern or a valid trade-off (after all, it’s not the union members who are saving on gas in a fleet purchase situation, so in their minds the risk-benefit works a little differently).

The title of the article was spot-on: Fear, But Few Facts.

I don’t know why there is so much misinformation and so much fear being spread about hybrids out there. I wrote Hybrid Cars: The Benefit of My Research (the 2nd link down in the static pages on the bar to the right) to try to distill some of my research over a year ago. Some of that information is starting to get out of date, but I don’t think that anyone has ever read it anyway, so I’m not sure if I should bother updating it with things like this.