Solar Storm

August 4th, 2010 by Potato

A quick note for those that haven’t already heard that there’s a solar storm going on right now, which should make the aurora borealis (northern lights) visible from much further south than normal (i.e., southern Ontarians have a chance at seeing them!). The opportunity should last for another day or two, but unfortunately the terrestrial weather isn’t behaving with the space weather: it was overcast and hazy here last night, and tonight might be more of the same… If you’ve got clear skies, and can get away from the light pollution, it may be worth taking a look up into the night sky.

Fear of Hybrids, Again

July 3rd, 2010 by Potato

I’m disgusted by this article in the Huffington Post. I’ve been warned about that rag and the quality of their science knowledge (worse than none) before, but it became the topic of some discussion over at PriusChat, and I had to check it out for myself. Note that I have ranted on this subject before.

The author describes her experience buying a Prius, after which she experienced headaches. She took the car back to the dealer, got a Highlander instead, and the headaches went away.

If that was all there was to it, it’d be fine: a weird anomaly, who knows why it happened, but her problem is solved so good for her.

But that wasn’t all there was to it. Because the Prius is a hybrid, she immediately jumped to the conclusion that somehow, the magnetic fields were causing her headaches. She then goes on to insinuate that these same fields caused “inflammatory” issues and a brain tumour in people she knows who happen to drive hybrids.

This is not evidence, it’s not science, it’s fearmongering of the worst sort.

To try to add weight to her arguments, she got a “meter” and tried taking some measurements of the magnetic fields on her own. And you know what, the only thing the general public fears more than magnetic fields are numbers, so you can bet that went well. She obviously did not know how the meter (or magnetic fields) work, because she only gives one number in the article.

Here’s the thing about magnetic fields: they’re kind of like sound. You have a frequency, and a strength. So to say you have a sound of 70 dB, or a magnetic field of 2 mG, doesn’t fully describe it. You’d also want to know if it was a deep bass thrum, or a middle C, or so many Hz for the magnetic field. And she doesn’t say that anywhere.

That gets particularly important when she pulls out this mystery meter. I’ll bet you dollars-to-doughnuts she’s trying to use a cheap “trifield” type survey meter, that only has a little dial readout for showing field strength. These are meant to be used around power line fields where you know the frequency you’re dealing with in advance, and they give very screwy results when presented with fields of unknown frequency and transients. Unfortunately, all we can say about the fields present in a car is that they are highly unlikely to be 60 Hz powerline fields.

Often, these meters are induced-current based, so if you have a 1 mG 60 Hz field, it shows up as 1 on the meter. But, if you have a 1 mG 600 Hz field, it shows up as 10 on the meter. So when someone who is unskilled at science or numbers — or much of anything really — gives a number in an article, I have basically zero faith that that number represents what they think it represents. For example, she says that just turning on the Nav and AC system in her car increased the field almost as much as the hybrid drivetrain did, but that makes little to no sense, on many levels. First off, the nav and AC shouldn’t draw nearly as much power as what’s needed to move the car (though all of these are well-shielded in a hybrid), so the measurement shouldn’t have gone as it did. And even if that was the case, it would mean that the nav and AC should be just as much a cause of her headaches as the hybrid drivetrain if she believes magnetic fields are responsible. She shouldn’t be out on a crusade against hybrids, but against in-dash nav systems!

She justifies getting a nav system in her Highlander by saying that the slightly smaller Prius “compacts” the fields, again showing that she doesn’t understand how things work — the extra space in the SUV is wasted, the design constraint still puts the nav system at arm’s reach for the driver.

She then goes on to insinuate that hybrids pose a health danger, remarking that “I started to wonder about my clients who drive hybrids. Every one of them has an inflammatory issue that baffles me…” Her byline says that she’s “Yoga, health expert”. What do you want to bet that every one of her clients, no matter what they drive, has “an inflammatory issue”?

The conclusion though was the biggest tip-off for anyone remotely familiar with the FUD surrounding hybrids that she was not a source to be taken seriously: she repeats some of the nonsense about the batteries and Sudbury, that has been debunked many times (including here), clearly indicating that she has not done her homework.

Scientific articles have peer review systems to try to catch these kinds of glaring errors, and those occasionally do fail (recently, our group tore apart an article, providing 3 pages of corrections, and the other reviewer said simply “it’s fine”). But the mainstream media, which should be more careful since it deals with a more credulous audience, often has much more glaring mistakes present — perhaps because journalists are equally credulous when it comes to technical matters.

All that said, we return to the issue of her headaches. It’s been said that we can’t disagree with the fact that she experienced headaches that went away when she changed cars. I’d say that we could disagree with even that level of evidence (did she make it up to get a controversial article out that other people would cite, even if just to debunk her?), especially given how subjective and random headaches can be. But, let’s grant that her headaches did happen, and even that they went away with the change in cars. It could be that the headaches were unrelated to the car itself, and could have been due to the stress of buying a new car, worrying about finances, etc., and would have gone away in a few days/weeks anyway. But even if we grant that somehow, the headaches were due specifically to the car, that does not lead us to blame the hybrid transmission and/or magnetic fields. There simply is no evidence of that. She had an individual problem, and she solved it by changing cars, and that’s great for her. But it’s misleading to then go and blame one specific aspect of the car without any evidence. She could have been allergic to the ecoplastic used in the dash, or to a host of other things. My favourite theory revolves around the rearview mirror: the Prius is a great car and I love it, but the rearview mirror is horribly low. I’m constantly ducking my head to look under it to check for pedestrians as I make a right turn, and if she was doing the same that repetitive head-ducking motion could have given her a headache. Or, similarly, the rear spoiler splits the rear window, at just about the height most cars’ headlights fall. If she’s driving down even a moderately bumpy road, their lights would constantly strobe to her point of view as they disappear behind the spoiler and reappear above or below it.

There are numerous reasons why this car in particular could be giving her headaches, and unless she’s willing to get back in it for some experimentation, we can’t say what factor could be responsible (if any). It brings us back to the issue of placebos: for an individual person, a placebo may work to solve their problem, such as a headache. They may be willing to pay money for a placebo (e.g., a homeopathic tincture). On the individual level, that’s fine: do what you need to do to solve your individual problem. But on a societal level, we don’t want to ascribe efficacy to what we know are really just placebos and have them for sale in our pharmacies, because it’s not good science, and it’s not good policy. Likewise, we don’t want to go around banning things like cell phones and wifi and hybrids without evidence that they are indeed causing harm (and if she’s afraid of hybrids, man, wait till she sees some of the controversy over cell phones!).

Finally, a quick repeat of my note on risk vs benefits. We know that hybrid cars have demonstrable environmental and financial benefits. We know that they can reduce our individual exposure to known carcinogens (e.g.: diesel), and our societal exposure to other pollutants. We don’t have good evidence that they even do have increased magnetic fields inside of the passenger compartment, and if they did, whether those fields would be harmful. The risk-benefit right now is highly likely skewed towards there being a worthwhile benefit, but because people are so afraid of the unknown, the unknown risks are large in their minds, and lead to articles like this one.

MRI Safety – The First Draft

June 9th, 2010 by Potato

For the curious, here is my expanded first draft; I should say emphatically that my coauthors on that paper are not responsible for what’s said here, this is all BbtP baby. As you can see, a lot was cut out to fit in the space provided, and to not come off as some guy ranting on a blog. Fortunately, this is the perfect venue for an article that comes off as a guy ranting on a blog! For those who have no idea what this is a first draft to, don’t worry about it, this stands on its own.

In Science (vol 327, p931, 19 Feb 2010) a little article came out describing the difficulties researchers in China were having with their studies of functional magnetic resonance imaging in children specifically to get healthy children to volunteer for a scan to act as controls for their patient group.

Intending to enroll children in the study, university students last December handed out fliers at a primary school. But they came away empty-handed: Parents were worried that MRI scans might harm their children. […] parents are reluctant to expose children to strong magnetic fields.
[…]
After 3 decades in the clinic, MRI is considered safer than x-ray scans and proton emission tomography, says physicist Yihong Yang, chief of the MRI physics section at the National Institute on Drug Abuse in Baltimore, Maryland. The main danger is for people with a pacemaker or other metal in their bodies. “Millions of people have been examined with MRI so far; thus it seems now very unlikely that there would be a side effect,” says Arno Villringer, director of cognitive neurology at the Max Planck Institute for Human Cognitive and Brain Sciences in Leipzig, Germany. […] Recruitment goes more smoothly in the United States, where “many parents will allow their children to take the test…”

There is some balance though:

…that reassurance cuts little ice with many parents—and some scientists. “I would not dare to allow my children to be tested by MRI,” says radiologist Han Hongbin of Peking University Third Hospital. “Nobody can ensure that there is no potential danger,” such as during nonroutine MRI scans that use extremely powerful magnetic fields, he says.

This is a very tricky ethical dilemma, for a number of reasons.

Stating that “millions of people have been examined with MRI so far; thus it seems now very unlikely that there would be a side effect,” is an irresponsible statement to make in the face of empirical evidence to the contrary. We know that there are deterministic effects of the fields used in MRI: strong, rapidly changing gradient fields can stimulate nerves to fire; radiofrequencies can cause heating; strong static fields can create projectiles out of metal objects. There are safety limits and procedures in place to attempt to control these effects in MRI scans, but there may still be stochastic effects present. Indeed, it is well known that at high fields some people may experience nausea/vertigo, or a metallic taste. Several studies have examined the effects of the time-changing fields. These effects are not necessarily negative: Rohan et al. [2004] found that a particular MRI scan could improve mood in bipolar patients, and the undesireable effects are subtle and fairly easily managed. The effects are also not necessarily chronic, but the possibility that more exist that we have not yet discovered must be accounted for, particularly when imaging subjects that will have no medical benefit from the scan.

This becomes a particularly touchy issue when children become involved. There are many processes that affect developing organisms more severely than fully matured ones. Some early research into the effects of electromagnetic fields suggests that this may be the case for something like an MRI as well. The fact that millions of adults have been scanned over the past ~30 years may be cold comfort to a parent volunteering their child.

For some biological effects there may be a long latency time as well, before effects can be observed. Solid tumor formation, for example, may take over a decade to manifest after ionizing radiation exposure. Good, long-term epidemiological studies will be needed in the future, alongside basic experimental studies on animals and cell cultures, to arrive at a good answer to the question of whether there are biological or behavioural effects of MRIs, and what they might be. Indeed, it is well known that there is a slightly increased risk of cancer formation from the ionizing radiation present in an x-ray/CT scan. However, if we were at the same point in ionizing radiation-based imaging as we are with MRI — millions of patients scanned, but little long-term follow-up looking specifically for effects — we might not be able to find that risk! Absence of evidence is not proof of the absence of risk, and it is widely accepted that there are small, but non-zero risks associated with CT. Accordingly, it has been appropriate to adopt the precautionary approach, and apply the dictum of ALARA – as low as reasonably achievable – to ionizing radiation dose.

I’m not in any way trying to be fear-mongering: fuller understanding of the processes is needed to mitigate these potential risks. Gadolinium-DTPA was for a long time used as a contrast agent and was understood to be safe. Recently, it has been determined that it can have severe side-effects in some people. These risks can be managed, for example through kidney function tests to determine who may be at risk. Any behavioural or biological effects of MRIs may likewise be managed in the future once they are better understood.

Hoping that there are no effects, without rigorously pursuing the matter in a scientific manner, will not be beneficial in the long run. More research on the potential biological effects of MRI, especially in children, is needed.

We can’t say for sure yet, and will indeed never be able to say with full confidence that there are no biological effects of the fields used in MRI. At this point we can probably agree that any effects, in adults, are not so severe as to counterbalance the usefulness of MRI as a diagnostic and research tool. As more research is done, we will either uncover what the effects are exactly, or continue to narrow down the maximum effect that we could discover with the population tested. With children, however, the studies have not been done, and our confidence that MRIs have no effect is not particularly strong.

And note that I say this as someone who depends very much on having volunteers step up to get an MRI for research purposes, and as someone who’s had a dozen MRIs himself. For an adult, having an MRI is safer than going for a short cruise in your car, a risk that people take for trivial benefits on a regular basis, so I completely understand when someone steps up to help science (and make a few bucks themselves). For children though, we just don’t know. Ultimately it’s the parents’ decision, but informed consent means that the researchers should try to educate them about both sides: the benefits and research aims as well as the potential, unknown risks.

A study is going to be better scientifically if it uses healthy controls to compare to a patient group (in this case, ADHD), rather than a different patient group (such as epilepsy) where the region of the brain being studied is likely not affected. However, that has to be balanced with the ethical realities of doing research.

Rage

April 16th, 2010 by Potato

To break down what it is I’ve been doing for the last few hours, I take recordings of the electrical activity of someone’s brain, it looks something like this:

EEG squigglies prior to hours and hours of work

Lots of squigglies. Too many, in fact — some of those squigglies are the influence of the electrical activity of the heart and of outside sources (like the MRI we stick them in), and they don’t represent the brain activity that we’re looking for. So, you spend a few hours playing with various computerized filtering techniques to get rid of those influences and get something like this:

EEG squigglies after hours and hours of work

Presto-boom-o, you’ve got some more-or-less pure brain activity to look at. Repeat it about 50-60 times for all your subjects (PS: still need subjects, enquire within), throw them all together for some groupwise stats, shake it up, have a cookie, and go write it up to share with the world.

Unfortunately, tonight has not been my night for analysis. The stupid program keeps crashing randomly, and now I’ve gone back to look at some of the saved data from earlier in the night:

Where the fuck have my squigglies gone?? You data-corrupting whore of a program!!

No squigglies.

WHERE ARE MY SQUIGGLIES??!!

Anger and frustration do not even begin to cover it.

G&M Publishes Bad Science

March 18th, 2010 by Potato

The Globe and Mail looks to have been taken in by a perpetual motion machine type scammer in today’s article “Texas university has eureka moment for coal-to-gas”.

I’m not saying that there’s necessarily anything wrong with the main topic of the article: it is possible to make gasoline or other liquid fuels from coal, and researchers in Texas may have found a way to do so economically. What I take issue with are these lines:

“Far better, he said, to capture CO{-2} right at power plants and convert it into crude on the spot. ” … “Assuming, arbitrarily for the moment, that Texas has struck oil in a huge way yet again, UTA’s announcement shows that energy research has finally begun to move in the right direction – simultaneously toward clean coal and the commercial exploitation of carbon dioxide. The reasons are obvious. The world has enough coal reserves to last for centuries. And it has enough CO{-2} – used as an abundant new raw material – to last forever. Harnessed together, this cheap coal and this greenhouse gas could drive the global economy for hundreds of years. “

Carbon dioxide is the product of burning fossil fuels. You have some energy-carrying molecule, you release the energy, and you get carbon dioxide. In order to take carbon dioxide and turn it back into an energy-carrying molecule (oil, coal, sugar, whatever), you have to have a source of energy to get the energy back into the system. For biofuels, this reaction takes place inside plants using energy from the sun. To think that you can simply take the carbon dioxide from a power plant and convert it to crude on the spot is ludicrous — akin to the perpetual-motion machine ideas like putting a windmill on your car.

On top of that, it doesn’t sound like much of a breakthrough: a tonne of coal has something like 15 GJ of energy. To turn that into 1.5 barrels of oil would reduce that to something like 9 GJ of energy, and only about 25% of the mass. Where has the other 1500 lbs of coal gone? Probably used up to supply the energy for the conversion, and out as carbon dioxide. It may be economical (due to the cheap price of coal vs oil), but it’s not particularly green or efficient. Except for rare cases where liquid fuels are needed for range (or where you need to keep the tanks in the blitzkrieg rolling, no matter how much of your total energy reserves it eats up), for transportation purposes it would be far better to burn the coal to make electricity, and then use electrified transportation, than to convert it to gasoline at that kind of conversion ratio.

Update: I contacted Mr. Reynolds at the Globe to inform him that something wasn’t right in his article. He provided me with the original source, which still is missing that key ingredient of how this isn’t just a perpetual motion machine:

“Though refining the technology for converting coal and oil shales to oil is a CREST priority, converting smokestack carbon dioxide to hydrocarbon fuels is also high on the research list.

“The idea that we can dispose of massive quantities of greenhouse gases like CO2 by piping them underground or into the oceans is not very practical,” Rajeshwar says. Better to capture carbon dioxide at power plants and cement plants, convert it to carbon monoxide and then add hydrogen from a renewable source like the water trapped inside lignite coal to make what’s called syngas.

“What’s produced is a liquid hydrocarbon fuel—synthetic oil—from which we can then make any conventional fuel, like gasoline or diesel,” Rajeshwar says. “The oil produced is very similar to that produced from coal.”

These are not the only ideas making the rounds at CREST. Others abound but are not as advanced.

“This is not hypothetical academia,” Billo says. “What we’re doing here is producing real solutions to this country acquiring sustainable and affordable energy.”