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Rabu, 13 November 2013

If it scares, it leads

I can't really blame the journalists. They're effectively in the infotainment business. And if punters are more likely to buy newspapers with scary stories about genetically modified crops than newspapers taking the consensus of scientists that the GMOs that have made it through the regulatory approval processes have had a far more thorough going-over than ones that have used other mutagenic techniques, well, we can't really blame them too much.

It can screw up policy though. There's a pretty serious externality through the political system where bogus scare stories whip up demand for regulatory regimes. Politicians cater to those demands.

I've spent a fair bit of time at Offsetting hitting on this kind of theme around bogus studies of the social costs of alcohol that do much to inflame public sentiment against consumption but little to inform.

Today's edition: GMOs. A paper in Cell Research last year suggested that bits of microRNA from food could migrate into people and so GMO bits could be dangerous. Canterbury biologist Jack Heinemann then put out a paper arguing, as I understand things, that if the Cell Research paper were right, then GMO wheat could also affect gene expression in people via the same mechanism. Most scientists working in the area thought this nonsense; the Science Media Centre put out a few rebuttals.

Paul Gorman at the Christchurch Press covered the controversy, highlighting all the scary bits.
The Heinemann paper and the reporting on it have yielded some pressure on the government to take action.

The latest issue of Nature Biotechnology features a replication of the Zhang et al paper in Cell Research on which Heinemann's results built. The Zhang paper didn't replicate. From the accompanying Nature Biotechnology editorial:
In contrast to these findings, the report on p. 965 finds no evidence for uptake of plant miRNA168a in the plasma and liver of mice fed a rice diet. Enzyme-linked immunosorbent assay data from the current study also contradict western blots from the Zhang paper that suggested miR168a directly suppressed levels of low-density lipoprotein receptor adapter protein 1 (LDLRAP1) in mice. Finally, the miRagen study suggests differences in diet composition, rather than miRNA-mediated cross-kingdom gene regulation, likely account for alterations in low-density lipoprotein in mouse plasma.
But why put the paper in Nature Biotechnology rather than Cell Research, where the original report was published? In fact, the miRagen investigators did submit their paper to that journal but were told that “it is a bit hard to publish a paper of which the results are largely negative.”
We differ with this assessment and believe the paper is worthy of publication precisely because it is a negative result throwing light on a key research question.
The original finding from Zhang and colleagues that plant miRNAs are capable of cross-kingdom gene regulation was an extraordinary claim. It went against a large body of research in which the systemic administration of double-stranded RNAs was shown incapable of triggering the RNA interference pathway in humans (and mice). It also raised concerns that plant miRNAs could pose health risks to humans. Indeed, last March, an article published in Environment International (5543552013) went so far as to claim that gene modification of plants using gene silencing mechanisms raises concerns for human health and that these concerns are not adequately considered in food safety assessments. This prompted the regulator Food Standards Australia New Zealand to undertake an assessment of the scientific literature on the issue and to publish a position statement on the regulation of genetically modified crops developed using gene silencing.
Bottom line seems to be that FSANZ and the Science Media Centre were right, the Greens (again) were latching on to fringe findings that supported their priors, and the media ran a scare campaign.

The whole Nature Biotechnology editorial is worth reading. They worry a lot about publication incentives and replication work.

Forbes comments on it here:
A great illustration of the challenge of controlling ‘metastasizing misinformation’ has emerged with the publication of a fascinating and important article in Nature Biotechnology that sharply challenges a study that had made controversial claims that dramatically raised the fear factor about GMOs.
The backstory provides an intriguing look at how the anti-GMO industry and sycophant journalists work—and the consequences of flogging single studies to score ideological points.
...
Since the publication of the original Zhang et al. study, similar research has appeared and the paper itself has been scrutinized—and the results are devastating. In May, researchers at Brigham and Women’s Hospital in Bostonfound that healthy athletes did not carry detectable levels of plant miRNAs in their blood after eating fruit filled with these molecules, and struck out in finding traces in mice or bees. “We conclude,” wrote the authors, “that horizontal delivery of microRNAs via typical dietary ingestion is neither a robust nor a frequent mechanism.”
Then in June, a research team from Johns Hopkins University writing in RNA Biology reported that the results were likely a false positive that resulted from the technique his group used, bolstering the case of skeptics who argued that genetic material from food would have little chance of surviving the digestive system, much less crossing the intestinal lining to enter the bloodstream.
The knockout blow came last week with the release of a replication study published in Nature Biotechnology. A team of scientists led by research scientist Brent Dickinson, using proper controls, could not detect the same microRNA reported by Zhang et al. Bottom line, there was almost none of the original culprit, miR168a, identified (one found in every million miRNAs).  Moreover, they repeated the rice feeding experiment, saw the decrease in LDL that Zhang et al. had found and the changes in LDL did not depend on the availability of miR168a. Instead, the authors added another treatment that corrected an energy/protein imbalance caused by the all-rice diet and the LDL effect went away. In turns out that the LDL effect was a nutrition effect. Mystery solved.”
Ignoring the basic science—few scientists embraced the original Zhang et al. study as it contradicted the logic of previous findings—professional antis will no doubt criticize the replication study as an industry apologia. “Many will dismiss this study because it was done with cooperation from Monsanto,”Folta wrote in his analysis of the newly released paper.  On the other hand, the other cooperator was miRagen [Therapuetics], a company interested in small RNAs for therapies.  They have a vested interest in identifying mechanisms to orally administer miRNA and detect physiological outcomes. If they repeated Zhang et al.’s work it would have been a positive finding for their company, as I’m sure they get plenty of criticism for the viability of their potential therapies.”
...
Don’t hold your breath for rollbacks of their disgraceful journalism and public comments by LeVeaux, Laskway, Gurian-Sherman, Hansen and others whose statements have ranged from credulous to intellectually dishonest to fraudulent manipulation and misrepresentation of results. Expect chief GMO demonizer Jeffrey Smith—who is a charlatan—to continue to hype this unproven danger in his “analysis” of the “dangers” of GMOs. They are single study syndrome sycophants. As a group—and this includes a sizable cadre of web activists, organic extremists, foodie journalists and campaigning scientists—they cherry pick the handful of papers that support their point of view and ignore the vast majority of research that disagrees. Some might call them professional fear mongerers.
I continue to see no scientific basis for demands that GMO foods be labelled. It just feeds the panic. And I continue to update my priors on those who take the GMO fearmongering seriously. There are real social costs to feeding this kind of nonsense. Jenny McCarthy has much for which to answer; so too do the GMO-worriers.

Minggu, 23 Juni 2013

More scientists?

I like science. But I'm not convinced that pouring money into producing more scientists is the most effective way of generating the great things that come from science.

Economists typically recommend "keyhole" interventions. If there's some market failure, intervene at the most direct level to fix it. It's plausible that basic scientific discoveries - the kind that aren't really patentable but that can yield all kinds of later commercial applications - are underprovided relative to some ideal. There are then a few policy options:
  • Award prizes for those making worthy discoveries.
    • But, if the basic research is expensive and if research teams have a hard time getting investor funding for prize-seeking, then this may still underprovide discoveries. Prizes are great when you know what achievement you'd like to fund but you don't know who's best-placed to provide it.
  • Award grants to research teams likely to provide discoveries.
    • This requires the granting agency to be able to pick winning teams and, in small countries, can yield nasty procedural tradeoffs between nepotism (the awards committee gives money just to their friends or to people doing politically favourable work) and administratively expensive application methods
  • Be really generous with baseline University funding, then revise slowly over time to focus funding towards institutions that produce a lot of discoveries so that Universities sharpen incentives.
    • We've moved toward this in New Zealand with PBRF, but the whole process is ridiculously administratively burdensome, the amount of money at stake is pretty small relative to overall University budgets, and because new and important discoveries are pretty rare, the whole thing seems to reward number of journal articles. If one University produced two field medalists, that would get it a couple of PBRF As, but plenty of other places will get plenty of As without field medals. There's basically a big upperbound truncation problem where truly stellar work - the kind that should wind up getting the really big prizes - is under-rewarded. 
  • Encourage lots of kids to take science degrees. Encourage the Universities to expand their science offerings by paying them extra for kids taking science courses and for degree completion in the sciences as compared to arts or commerce. 
    • Increasing the supply of scientists could reduce the cost of scientists and thereby increase the supply of discoveries from those places that hire scientists. In a small country, you cannot really have much of an effect on equilibrium wages in science as you'll just induce post-degree out-migration. And to the extent that science grads get hired in applied shops that, while great, largely internalise the benefits of what they're doing, you've not done as much to get the new discoveries.
I expect that optimal policy would involve some combination of the first three mechanisms. Prizes in combination with baseline university research funding would solve some of the problems we'd otherwise have in providing extra rewards for truly top-notch stuff. And grants can help if there are particular things you want done and you think you know who can do it. If those together work to build demand for scientists, then that can automatically start pulling more kids into science when they see rising salaries and better job prospects.

What do we get when we push a lot of kids through general science degrees instead? Andrew Norton at The Gratten Institute has a few numbers for Australia.
The annual Graduate Destination Survey (GDS) of people with recently completed bachelor degrees consistently finds that people with science qualifications have above-average difficulty finding work. The only exception is for people with degrees in the geological sciences.
Three years on from the GDS, the Beyond Graduation Survey shows that the job outlook of science graduates improves with time. After a slow start their employment rate is only slightly below average.
But this is not evidence of strong demand for specific scientific knowledge. Only 57% of science graduates say their qualification is important or a formal requirement for their job. It is the second lowest match between qualification and discipline.
Norton concludes:
Nobody doubts that science and maths skills are important to Australia’s future. In some specialised areas, employers might struggle to find suitable graduates. But no enrolment or employment data suggests that we are headed for general shortages of science and maths graduates.

The science applications boom may turn out to be a higher education bubble waiting to burst. If it does, thousands of intelligent and capable young people may be left with qualifications that hamper their ability to find meaningful and rewarding work.
Note here that the point isn't that "being employed in a directly relevant profession" is an important measure of a degree's fitness - in that case, dentistry would be the best degree ever. Rather, it speaks to whether there's any great shortage. Were there a generalised shortage of scientists, we would expect most graduating scientists to be snapped up by employers desperate for scientists. Instead, if we look at the underlying data, we see that only 63% of those graduating with life sciences degree and 65% of those graduating with a degree in the physical sciences say that their qualification is either a formal requirement or "important" for their job. 24% of those with a life sciences degree and 19% of those graduating in the physical sciences say their degree is not important for their job; the rest say "somewhat important."

I wonder what the NZ numbers would look like.

The running joke on Big Bang Theory is that scientists make little unless they manage to luck into a good job with Pharma. Bernadette waited tables while doing her PhD. Two young physics faculty members share an apartment; their neighbour, a waitress, hasn't got a roommate and consequently has more substantial money problems. Another physicist only has any money because his father sends him remittances from India. A university engineering technician doing NASA-level work lives with his Mom. Closer to real life, Noah Smith explained grad school in the bench sciences.

Want more of the good stuff that comes from basic science? Find better ways of funding basic science.