Can Rotational Motion Effect Radioactive Decay?

This post is an analysis of "Changes of decay rates of radioactive 111In and 32P induced by mechanic motion" by YuJian He, Fei Qi and ShengChu Qi, located at http://www.springerlink.com/content/x1q13217t2427059/

Summary: Two different radioactive isotopes were put in a centrifuge and spun. The half-life appeared to increase if spun one way and decrease if spun the other way.
Claim: There is a difference and it can be explained by the chiral dependence of the weak force.

Question 1: Are the results "Significant"?
Statistically, is the proof strong enough to not just be a coincidence? Well... somewhat. For 111In they measure a "natural" half life of 2.83 +/- 0.03 days, clockwise is 2.75 +/- 0.03 days, and anticlockwise it is 2.88 +/- 0.03 days. None of this is the "3 sigma" difference which is necessary in particle physics (though not other fields) to claim an observation.

For 32P the natural is 14.29+/-0.03 days, clockwise is 13.75+/-0.03 days, and anticlockwise is 14.54 +/- 0.03 days. This is a "significant" observation if those errors are true.

It is somewhat unclear where these errors are coming from. They claim to fit their data in Excel, so perhaps that spit out a fit uncertainty. However, they quote the SAME errors for the other isotope even though the half life is an order of magnitude different. They don't provide any measure of "how good" their fit is - like a chi2 test.

Answer: Some of their results do not appear to be statistically significant. Their error bars are not explained so significance cannot really be judged. I can't say their results are "wrong", but they are not good science

Question 2: Is the mechanism they explain the effect with reasonable?

This is dangerous territory since they appear to be chemists and anything effecting radioactive decay half life would be a physics process. Unfortunately this section is poorly written, presumably because English is their second language. This makes it somewhat difficult to tell if what they are saying is nonsense or if it just sounds this way. The general idea is that elementary particles have a property called chirality that relates to spinning clockwise or counterclockwise. It appears as if the authors of this paper try to relate chirality to all sorts of things.

The first problem is that the "physics paper" they cite to discuss the chiral nature of the Weak Force is a Scientific American paper from 1990. This is scary! Scientific American has articles on whether robots will rule the world any time soon. It is not a good source for citing the fundamental rules of the universe. Yes, there is a preference for particles to "spin" clockwise vs counterclockwise. I don't think the authors understand what this means.

Spin is a technical term in physics and is inherently quantum mechanical. It is possible to align the spins of particles, but it must be done on a quantum mechanical level. The authors haven't modified the orientation of the spins of the atoms in their sample (for instance, by putting them in a very strong magnetic field like in MRI or cooling them down to almost 0 kelvin) so they will be randomly distributed. Basically, the motion of the centrifuge in this paper is too "big" for the individual atoms/particles to know that there is a difference between clockwise and anticlockwise.

Answer: No, they seem to misunderstand the physics concept they are citing

Final Conclusion: The most generous judgment is that they misunderstood the physics process and didn't properly consider their sources of measurement error. I would judge it "Sloppy Science" and am surprised it was published in a peer reviewed journal. Perhaps the reviewers didn't understand the physics either.

Science: Made in China?

Unfortunately the "rules" about diagnosing "Bad Science" break down when the research is done in another country, such as China. There are brilliant Chinese Scientists. There are wonderful research facilities and institutions in China. But there can also be a lack of communication between Science in China and Science in the USA.

So here is the scenario:

• A paper is published in a Chinese Chemistry Journal (in English) in 2007
  
• The journal is peer-reviewed
  
• One of 3 authors has no affiliation; the other 2 sound like good Chinese Institutions
  
• The results are surprising and have consequences in Physics, Chemistry, and Biology
  
• The authors explain the strange result via Physics, but are in Chemistry Departments
  
• It has only been cited 2 times, once by a different group not able to confirm the results and once by the original group rejecting the results of the 2nd group.
  
• There are some communication issues in the paper; it isn't written in the "scientific tone" that I am used to
  
• Of the 12 references, 6 are to papers written by the same authors
  

Diagnosing "Bad Science"

Science is often referred to as one entity (especially in political discussions), but there is no specific line between what is "Science" and what isn't. There is a bunch of "stuff" that gets done by people (many of whom call themselves scientists) and some of this "stuff" is done more scientifically than others. The scientific method we teach in primary school (make a hypothesis, test the hypothesis, etc) doesn't always map well to the research industry. Much of the time - especially in interdisciplinary research - it is difficult to know all of the possible effects and think of all of the variables.

Hence, there is a system for people (who identify as scientists) to discuss research. One arm of this system are conferences - face to face meeting filled with talks and posters. Another is journals, especially the "peer reviewed" ones.

Paper Submitted!

My first paper is submitted to the Journal of Nuclear Medicine. This isn't to say it will be appearing - I've just sent it. Some editor will glance at it and decide if they should bother having someone else look at it in detail.

I've learned a few very important things in this process:

• ROOT sucks at making nice looking plots.
  
• It is important to look at the submission interface far before actually trying to submit.
  
• Histograms make more sense in particle physics than anywhere else.
  

I'm sure I will have much more to learn during the review process (if/when it occurs). Probably that the reviewers hate my plots. I wouldn't blame them. It could have been worse. I could have wanted to show a stacked bar graph. ROOT won't do that at all. But hey, it will make great histograms!

Cerenkov time!

I've been scolded for not posting in a while. On the one hand, I've been very busy. On the other, I got a cute little netbook last week that means I can practically blog anywhere, anytime. Like in class. Which, I'm not in right now. Promise.

The real reason I got the netbook was because I am working on a few papers and talk and being able to get away from my desks to do so is quite nice. I've seen my desk at work a LOT lately, especially at strange hours. It won't get better for the next two weeks.

I've been working on one project from December to March. I started working on the paper in January, submitted a draft as a conference abstract (which I find out about tomorrow), but found a few issues in the process of getting it ready for the conference submission. So the simulations were re-run...

And then I went back to my "other" project! The group has done some Cerenkov work and I meant to do simulation work back in the fall. I hit a wall (optics) and gave up... for a longer time than intended. So I'm working on Cerenkov "full time" again. Why? Back in January I submitted an abstract on Cerenkov to APS April meeting, thinking I was "almost done" with my other project. Silly silly me.

So with 1 month to go till April meeting, I had to get my act together and have something to show. So I presented a Cerenkov paper at group meeting to get me back in the right mindset... and found an exciting thing. That I had simulated and written up in a week. So that (short) paper is now in the editing stage and I hope to get it submitted to the Journal of Nuclear Medicine very very soon. Because I still need to work on the part of the Cerenkov simulation I said I was going to do for April meeting! In 2 weeks! That it now looks like I might be giving a press conference at.

While it might be silly to try to give a press conference on what I haven't done yet, it actually makes a lot of sense. Talks at April meeting are short - I have 10 minutes. And given that I want to present something on Biomedical Imaging to physicists, MUCH of that time will be spent on the basics of optical imaging. And then I can talk about Cerenkov Imaging (in general, with the work other groups have done over the past 2 years). And then I will have time to show 1 or 2 slides on MY work. Some of which will be what is in the paper I wrote this weekend.

So likely the press conference will be mostly about Cerenkov Imaging in general, and little about what I have done myself. I think that is ok. Usually the "big" results come from big collaborations - people present on behalf of 100 or more researchers. It is just strange to be presenting research done by a bunch of people who I don't represent in any way. I will give lots and lots of credit to other researchers and I will try very very hard to use data out of my own group whenever possible. I think Cerenkov Imaging is really neat and I would love to share it with journalists. If I just share with them my simulation data they won't think it is very neat... it is the big picture they'd like.

Of course, I'm not as crazy as I sound. I've scheduled a SASS (SLAC Association for Student Seminars) talk for the Wednesday before I go to April meeting (you know, next week) so I need to have everything ready for THEN. So I won't be working up until the last minute before April meeting. I'll be working nonstop until next Tuesday. And then taking the questions and comments from SASS and using them to improve my talk for APS.

So I haven't had much time for blogging lately, and I'm not sure when I will have time again. Possibly when my second paper is submitted...

Happiness in Medicine

Again and again, quality of life (QOL) in different forms is shown to correlate to better recovery from cancer (and other health issues). I find these papers depressing - we'll never get health insurance to pay for trips to Disneyworld, better food, or social programs for people with cancer. A recent paper in the Journal of Clinical Oncology shows a correlation of this type, but claims no causation:

Title: Decrease in Depression Symptoms Is Associated With Longer Survival in Patients With Metastatic Breast Cancer: A Secondary Analysis

Authors: Janine Giese-Davis, Kate Collie, Kate M.S. Rancourt, Eric Neri, Helena C. Kraemer, and David Spiegel

Pictures from Snowpocalypse