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Brief Items: Chem Wiki, Autism/Vaccines, Solar Cells

Kyle Finchsigmate of The Chem Blog is starting a wiki site for chemistry lab techniques – have a look here.
Here’s an excellent overview of the vaccine/autism stuggles, from PLoS Biology. The take-home message: a lot of people in the general public care about a compelling narrative, and many of them don’t give a dirty sock for statistical proofs.
Are solar cells really going to end up looking like this?

18 comments on “Brief Items: Chem Wiki, Autism/Vaccines, Solar Cells”

  1. photon says:

    organic solar cells are a farce

  2. partial agonist says:

    Wow, that autism / vaccine overview is depressing. It’s hard to know what to do as a scientist if the lay public just downright refuses to believe your data. You hate to just give up, but more data disproving a pet theory seems to energize the pet theory.
    A side note- Thimerosol is almost never used as the preservative in childhood vaccines any more, so the chemical that caused all the hype in the beginning has mostly been removed from the equation:
    http://www.fda.gov/CbER/vaccine/thimerosal.htm
    “Thimerosal has been removed from or reduced to trace amounts in all vaccines routinely recommended for children 6 years of age and younger, with the exception of inactivated influenza vaccine (see Table 1). A preservative-free version of the inactivated influenza vaccine (contains trace amounts of thimerosal) is available in limited supply at this time for use in infants, children and pregnant women. Some vaccines such as Td, which is indicated for older children (≥ 7 years of age) and adults, are also now available in formulations that are free of thimerosal or contain only trace amounts. Vaccines with trace amounts of thimerosal contain 1 microgram or less of mercury per dose.”

  3. anon says:

    “It’s hard to know what to do as a scientist if the lay public just downright refuses to believe your data.”
    We live in a country where significant numbers of people believe Fred Flintstone had a dinosaur for a pet.
    Added to that, the public, no doubt, lumps together the scientists who study vaccine safety with their upper management; people like Jeff Kindler, that is– people with less overall credibility than hedge fund managers.

  4. fred says:

    “organic solar cells are a farce”
    Photosynthesis is nearly 100% efficient. You got a silicon cell that beats, say, 20%?

  5. metaphysician says:

    #4 fred- citation? Because I’m nearly 100% certain that’s impossible, unless chlorophyll became more efficient than a Carnot engine when I wasn’t looking.

  6. XIMIK says:

    #4 fred – it seems you are 10-1000 times off:
    http://en.wikipedia.org/wiki/Photosynthetic_efficiency
    Unless you come up with a different definition of efficiency…

  7. D. says:

    Photosynthetic efficiency is .1-2% for most plants, up to 8% for ideal sugarcane. Plants require inputs besides light and produce biomass rather than electricity, so running through a gasifier or boiler loses 10-20% of total energy before we account for cost of collection or cultivation, putting maximum biomass->electricity efficiency around 5%. Organic solar cells can probably do better.

  8. metaphysician says:

    They damn sure aren’t going to approach 100% though, unless you create a breed of organic solar sell that likes growing at near absolute zero.

  9. VanillaGorilla says:

    Re Organic Solar Cells
    While the Torres group has certainly done a lot of cool things in the past i don’t really think this is one of them. Seems a lot like they took the projects from two ends of the lab and stuck em on each other.
    Pretty pictures tho..

  10. fred says:

    “#4 fred- citation? Because I’m nearly 100% certain that’s impossible, unless chlorophyll became more efficient than a Carnot engine when I wasn’t looking.”
    I stand corrected. I was using a number from the popular press, which, apparently does not stand up to scrutiny. I think “D” got it right.
    But, to quibble: I don’t think the Carnot cycle is relevant because the Carnot cycle refers to heat engines.

  11. metaphysician says:

    #10 fred- Doesn’t really matter, as a Carnot cycle is also the theoretical most efficient possible engine arrangement. Whether you use a pure heat engine design, or a chemical mechanism, you cannot get better efficency than a Carnot cycle.
    ( and remember, temperature is ultimately a measure of energy density, so you still have a source and a sink, calculating the equivalent temperature between the two is just trickier )

  12. Will you give your dirty sock designation to Dr. Bernadine Healy, Dr. Julie Gerberding and Dr. Duane Alexander who have called for more research on vaccine autism issues? Dr. Healy has pointed out that the epidemiological studies do NOT address vulnerable populations subsets and that the IOM 2004 Report on autism and vaccine safety actually discouraged research that might provide more information about POSSIBLE vaccine autism connections.
    Then there is Dr. Jon Poling a neurologist who apparently cared a “dirty sock”, whatever you mean by that cheap insult. when the vaccine autism claim he initiated on behalf of his daughter was settled by the government. Dr. Poling is one of those ignorant members of the public who has also called for more research of possible vaccine autism connections.
    Dirty socks, clean socks, clean up your act.

  13. metaphysician says:

    Honestly, I’ll care about alleged autism connections the moment *somebody* claiming a connection admits “But even if there is one, *we all still need to get vaccinated*.”
    Because a miniscule chance of autism is a worthwhile trade to avoid a vastly higher chance of a half dozen deadly diseases.

  14. Cloud says:

    @Harold- go read the PLoS article Derek references. Here is the relevant bit:
    “The DHHS conceded in November 2007 that vaccines aggravated an underlying mitochondrial disorder in the baby girl of a Georgia couple, Terry and Jon Poling, ultimately causing regressive encephalopathy with features of autism spectrum disorder. Their decision was in line with previous table injury rulings that a measles-containing vaccine can exacerbate an existing encephalopathy”in this case, caused by a mitochondrial enzyme deficit. The condition shares symptoms with ASD, but is distinct.”
    To those wondering how to get the science on vaccines across to the public, I’m pretty sure that calling the public stupid is not the way to go.
    I vaccinated my child on the recommended schedule, and we had absolutely no side effects beyond a fever or two. I watched a measles outbreak spread around my neighborhood when my daughter was 11 months old- so 1 month shy of getting her first MMR shot. That was not a fun month. I am firmly in favor of vaccination.
    However, in defense of the parents who are confused- pregnancy and early parenthood is a time when you are asked to make a lot of decisions with really incomplete information about risks and benefits. In many cases, the studies just haven’t been done. Also, doctors are often no help, probably fear of being sued- as an example, I got a sinus infection while I was still breastfeeding. The doctor I saw would not state that it was safe for me to take amoxycillin for my sinus infection while breastfeeding. This despite the fact that I was simultaneously treating my baby for an ear infection with… amoxycillin. I think he was trying to leave the decision to me, so that if something did coincidentally happen to go wrong, I couldn’t come back and sue him. Faced with this sort of situation, parents feel they should do their own “research” on things to try to make the best informed decisions. Of course, their tool for research is Google, not PubMed. Even if they find scientific articles, most people do not have the training to evaluate what they find. I guess we shouldn’t be surprised that some people end up believing some strange things.
    I’m not sure how to unwind this mess. When I run across misinformation on the parenting sites I frequent, I always comment and correct it, and point people to the Science-Based Medicine site or something similar. I’m always amused when someone says that helped them. Why do they trust some random person on the internet (who won’t even give her real name!) but not the pediatrician they have presumably carefully selected?

  15. TFox says:

    Re: vaccination. I ran the numbers for risks vs benefits for a couple of childhood vaccines, and indeed, the benefits dramatically outweighed the risks for all the standard ones. However, *both* benefits and risks were dramatically outweighed by the risk of the car trip to get the vaccine! So a truly rational decision would have been to skip the vaccination, not due to the risk of the vaccine, but due to the car trip. Irrationally, we had our kids vaccinated anyway, figuring that otherwise, to be consistent, we’d have to spend the rest of our lives in bed.
    Carnot efficiency of photosynthesis: the hot side is the temperature of the radiation, ~5000K for the sun, so the max theoretical efficiency is quite close to 100%. Practical efficiencies are much lower.

  16. Anonymous says:

    TFox-
    1. That would only apply if you only look at each single car trip independently, rather than at the marginal risk of one additional car trip. The risk/reward balance looks a lot more favorable when you realize you are either going to be driving a lot anyway, or you have to give up a *lot* more than just one set of vaccinations to avoid the driving risk entirely.
    2. True if the solar cells were in direct thermal contact with the sun, or equivalent. However, the 1 AU worth of distance between the ultimate hot side and the engine, means that it isn’t really the hot side for all practical purposes.

  17. Still Scared of Dinosuars says:

    “We live in a country where significant numbers of people believe Fred Flintstone had a dinosaur for a pet.”
    and that yappy monster sent me off into a lifetime of therapy. 😉
    TFox – As far risks of travelling to get vaccinations I don’t buy that you’ve “weighed” anything. First of all, I’ve never driven my kids to get vaccinations, I’ve driven them to very valuable annual physical examinations at which vaccinations were given. Second, what risks are you weighing? Temporary injury, permanent disability, death? How do you add that up?
    I think you were glibly making a point that I’m perhaps taking too seriously. The connection to the original discussion is that the same question of what risks are you weighing and what weights you are attaching to them apply. It requires careful statistical reasonning and clear rational judgement neither of which is of much value without the other.

  18. TFox says:

    Boy, you get responses quickly when you call vaccination irrational! I’ll plead guilty to being glib, and to having presented my analysis casually. To be a bit more serious, I think the numbers demonstrate the level of care required to actually do these types of analysis in a reasonable way. I think my real argument was a kind of reducio ad absurdum — all the relevant numbers were far less than the risk of the car trip, however measured, which is already a risk that I willingly accept. Therefore, further consideration was pointless. If risk minimization is my sole criterion, I should stop studying the vaccination question, choosing to follow the recommendations of reasonable people who’ve studied this stuff more carefully (eg the CDC), and, most importantly, spend my time productively as far as relevant risks, such as checking that my car seats are installed properly. Which is what in fact I did.
    @16 re sunlight: the color of the light is the relevant question, and that doesn’t change much in 1 AU. Insulate a black body on the Earth’s surface and put it in radiative contact with the sun (ie outside) and it will equilibrate to 5000K, the color of the light. For distant galaxies, the color will shift due to dust and doppler. The intensity of the light will change with distance (~r^{-2}), which will affect the rate of equilibration, and how good your insulation needs to be, but not the temperature. HTH.

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