Category Archives: Body

Looking for a Straw-Colored Needle in a Large Haystack

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There’s a bit of buzz about the WHO characterizing cell phones as “possibly carcinogenic to humans”. This is a pretty detailed explanation of what that means, from Ed Yong (I think; the link that brought me here said so, but I don’t see Ed’s name on the page anywhere)

World Health Organisation verdict on mobile phones and cancer

What does that mean?
It means that there is some evidence linking mobile phones to cancer, but it is too weak to make any strong conclusions. Specifically, IARC’s panel said that the evidence that mobile phones pose a health risk was “limited” for two types of brain tumours – glioma and acoustic neuroma – and “inadequate” when it comes to other types of cancer.

The Chairman of the group, Dr Jonathan Samet, said, “The conclusion means that there could be some risk, and therefore we need to keep a close watch for a link between cell phones and cancer risk.”

The post goes into some detail about why this is really a non-issue: there is still no proposed mechanism, there are obvious flaws in some of the studies and there are a lot of conflicting results. That last part ties into an important point — the underlying reason that researchers are getting conflicting results is because the system being measured is inherently noisy and the effect under scrutiny is small.

The increased risk‚ from one of the studies (remember, there are others that saw no increased risk), is a 40% increase of those two types of brain tumors, which sounds like a lot, except … you need to look at this in context. Even a substantial increase in a small risk still leaves you with a small risk. We’ve seen this before with traffic analysis, and now we have it for cancer analysis. Matthew Herper has already run the numbers

96% of the U.S. population, or about 300 million people, have cellphones. If everyone’s risk of glioma went up 40% as a result of cellphone use, the number of gliomas in the U.S. would increase by 8,000. That’s a one in 40,000 increase in each person’s risk of glioma, which still isn’t very big.

But the study the WHO is citing only showed the 40% increase in the 10% of people who used cellphones most. I don’t know how many people in the U.S. would now fall into this group, but we’d be talking about maybe hundreds of cases spread out over the whole U.S. population.

We can look at this another way. A fair amount of data has not yielded a statistically significant result. Any signal that exists is still buried in the noise, requiring more statistics, but until you get those statistics, you can’t rule out an effect. What you can do is say that the effect is no larger than some amount, and what is probably the worst-case scenario analyzed above — in the unlikely event the study wasn’t an aberration — yields a very small risk. Which is probably why the collective response of scientists has been “meh”

It's Ungodly

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The Dangerously Clean Water Used To Make Your iPhone

The ordinary person thinks of reverse-osmosis as taking “everything” out of water. RO is the process you use to turn ocean water into crystalline drinking water. And in human terms, RO does take most everything out of the water.
But for semiconductors, RO water isn’t even close. Ultra-pure water requires 12 filtration steps beyond RO. (For those of a technical bent, the final filter in making UPW has pores that are 20 nanometers wide.
…
Water is a good cleaner because it is a good solvent–the so-called “universal solvent,” excellent at dissolving all kinds of things. UPW is particularly “hungry,” in solvent terms, because it starts so clean. That’s why it is so valuable for washing semiconductors.
It’s also why it’s not safe to drink. A single glass of UPW wouldn’t hurt you. But even that one glass of water would instantly start leeching valuable minerals back out of your body.

And Now, My Beauties, Something With Poison in it, I Think.

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Chemistry of Morphine, Heroin, and Lemon Poppy Seed Cake

You’ve heard the warnings – don’t eat poppy seeds before taking a drug test. The seeds can trigger a false positive reading for opioids, making your potential employer think you could be a heroin addict. A few years back, Mythbusters reproduced the anecdotes, showing that just two poppy seed bagels was enough to make Jamie test positive for drugs. (Other studies have shown the same thing.)

I like saying that I eat poppy seed bagels for the plausible deniability whenever I’m within earshot of my boss.

You'll Only Look Like Stretch Armstrong

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Mind tricks may help arthritic pain

“We were giving her a practical demonstration of illusory finger stretching when she announced, ‘My finger doesn’t hurt any more’, and asked whether she could take the machine home with her. We were just stunned – I don’t know who was more surprised, her or us.”

I wonder how closely this is related to the phantom pain solution of amputees

Before TMI meant TMI

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TMI: Fear, Fukushima and Facts

A critique of the xkcd radiation dose chart I linked to, with some more details and caveats, some of which I recognize as true from by background (but wasn’t going to post on my own because it’s too far away from my areas of competence). Randall’s shortcoming is the mixing of chronic and acute exposure doses (long-term and short-term), which are not equivalent, i.e. a dose spread out over a period of time (e.g. months) does not have the same biological effect of the same dose that happens in a period of minutes or hours or days. Giving the body a chance to repair itself matters.

via fine structure

Over on the Other Side of the Line

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Understating the risks is just as irresponsible as overstating it.

The Mind of Dr. Pion: Don’t believe what the press is telling you!

There is no explicit by-line on this article, but the video contains an interview with BBC reporter Chris Hogg in Tokyo that repeats that a half life of 8 days means “that after 8 days the risk will have dissipated”.

The reporter is WRONG. Twice, because that is also not what the officials said. His ignorance of basic physics, in this case a topic I always teach in a college general education class, led him to misinterpret what was actually said by a government spokesman and hence mislead the public.

Let's Look at Some Radioactive Data

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Stock tip: invest in adult diaper companies, what with the soiling of undergarments going on about radiation levels in the US.

I’ve run across a number of stories about the worries and the run on iodine tablets, and then saw the California radiation monitoring map which led me to the EPA site. They give radiation levels for select cities, but don’t tell you what the expected background levels are, so all you have is the assurance that the detected levels are small. However, the EPA has set up a section dedicated to the Japan accident, which includes a map with the most recent data for all of their monitoring sites. I eventually found how to get historical data — you click on “Query View” over in the left column — and looked to see what I could find.

I chose Eureka, CA because it’s on the West Coast and I was excited to have found the database, and the beta count rate because that would be indicative of having fallout reach the US; many fission products are beta-emitters. (The gamma data is divided into energy bins, and would have taken longer to analyze.)

Here’s what the radiation levels look like, starting with March 10, up through a half-day’s worth of data on the 25th.

The earthquake happened in Japan on the 11th at 0542 UTC. You might think the first spike, on the 11th, might be caused by the quake/tsunami, but the cooling problems didn’t happen until about 8 hours had elapsed and it would take several days for any fallout to reach California. If you really think that either peak is significant, all you have to do is go into the database and look at a larger data set.

This graph goes back to early February. The two peaks shown on the first graph are near points 750 and 1000. We can see that the radiation levels are showing no unusual behavior.

Because the EPA has labeled levels coming from specific isotopes I have to assume that’s by looking at the spectrum, and they give numbers that are much less than a picoCurie per cubic meter. One Curie is 3.7 x 10^10 decays per second (based on the activity of a gram of Radium-226), which means that a picoCurie is about 2 decays per minute. The EPA isn’t clear that the numbers it gives for gross beta counts are for a cubic meter or a larger volume, but I think it has to be, because 0.0017 pCi (the Anaheim Cs-137 activity) is only about a quarter of a decay per hour, so I imagine they sample a much larger volume.

Vocabulary lesson: many MSM stories are confusing radiation and fallout/contamination. radiation (in this context) is the energetic particle emitted when something decays, e.g. a gamma or a beta. Fallout or contamination refers to the radioactive particles, such as particulate matter that was expelled from the reactor and contains radioactive particles. We aren’t worried about radiation reaching us from Japan, because that is diminished by distance. It would be like complaining that the lights of Tokyo are too bright and though I’m sure Sarah Palin can see them from her home, it’s simply not an issue for us. What matters is the amount of radioactive particles that might reach us, and decay when they are here. But we can’t see any effect on the radiation levels, because any increase is small compared to the background and fluctuations in the background.

To quote Hedley LaMarr, “Gentlemen, Please, Rest Your Sphincters!”

Sarah McLachlan Science

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A Mystery: Why Can’t We Walk Straight?

More like building a mystery*. Perhaps I am missing something, but I’m having a hard time understanding the “mystery” behind this. From a physics standpoint, we know that a moving object will travel at constant speed in a straight line if and only if there is no net force acting on it. Forces along that path will change the speed, so we don’t have to worry about that, and vertical forces can be ignored, since we aren’t going to start levitating or submersing ourselves in the ground. Which leaves us with the last component, which is perpendicular to the path. An acceleration perpendicular to the path gives you — ta da — circular motion. Physics 101.

I’m guessing the problem is in the assumption that the human brain could remove all biases in our locomotion and produce only forces along the direction of travel, without visual cues for feedback. Why would you assume that to be true? The surprise might be that there are biases rather than fluctuations, which would lead to a random walk (in the perpendicular component), but that’s still not a straight line. Assuming no noise processes at all is just naive.

*no data on if this effect holds while wearing sandals in the snow

Thtuck! Thtuck!

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You either need to learn about the concepts of thermodynamics, or you can watch A Christmas Story

Boy’s Tongue Stuck to Frozen Pole After ‘Christmas Story’ Dare

You’ve seen this scene before — every Christmas.

An 8-year-old Oklahoma boy got his tongue stuck on a frozen stop sign pole after his brother dared him to lick it.

No mention of an escalation from a double-dog to a triple-dog dare, however.