Archive for November, 2017

Nov 10 2017

Glyphosate Not Associated with Cancer

Published by under General Science

IARC-Headquarters_ExteriorIn March of 2015 the International Agency for Research on Cancer (IARC), part of the World Health Organization (WHO), published their assessment on glyphosate, Monsanto’s popular weedkiller, classifying it as 2a – a probable carcinogen. This was like red meat to the anti-GMO crowd, and even sparked class action suits against Monsanto and may lead to banning use of the chemical in the EU.

There were significant problems with the IARC report, however. First – it is at odds with every other expert review of the scientific literature on glyphosate. I review the evidence here, citing many expert panel reviews, all conclude that the evidence does not support a link between glyphosate and risk of cancer. The IARC conclusion is a clear outlier, which reasonably prompts questions as to why their designation stands out.

We also need to put the IARC classification of 2a – probable carcinogen, into context. This is the same classification that the IARC gave to drinking hot beverages or eating red meat. Overall they tend to err on the side of caution when making their classification.

But there were problems that go beyond where the IARC sets their threshold for “probable.” Two main criticisms have emerged. The first is the lack of transparency. Reuters has published a series of articles on the issue, outlining, for example, that when the EPA reviewed the safety of glyphosate they also published a 1300 + page document that outlines the entire deliberative process. The IARC produced no such document.

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Nov 09 2017

Evolution Caught in the Act

Published by under Evolution

The hypothesis that life on Earth as it is currently found is the result of biological evolution from a common ancestor over billions of years is supported by such a mountain of evidence that it can be treated as an established scientific fact. Further, it is now a fundamental organizing theory of biology.

This, of course, does not stop ideologically motivated denial. There are those who have been systematically misinformed about the evidence, and the nature of science itself. What they think they know about evolutionary theory they learned from secondary hostile sources. One of the common lies they are repeatedly told is that there are no transitional fossils.

This claim amazes me still, because the evidence is so easily accessible. Lists of transitional fossils are easy to find. One of my favorite examples is the evolution of birds, because the morphological transition from theropod dinosaurs to modern birds was so dramatic.

I also have to point out that this evidence represents a successful prediction of evolutionary theory. When Darwin first published his theory the fossil record was scant. Enough fossils had been discovered for scientists to see that life was dramatically changing over geological time, but the puzzle was mostly empty. There were not enough specimens to see connections between major groups. Evolutionary theory predicts that such connections would be found – and they were, and they continue to be.

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Nov 07 2017

Science-Based Veterinary Medicine

chiropractic_HorseThe Royal College of Veterinary Surgeons (RCVS) is a UK-based professional organization for veterinary surgeons and nurses. They describe their mission as:

We aim to enhance society through improved animal health and welfare. We do this by setting, upholding and advancing the educational, ethical and clinical standards of veterinary surgeons and veterinary nurses.

They recently came out with a statement regarding complementary and alternative medicine, essentially setting the standard for their profession in the UK. There are some good parts to the statement, but also some dramatic weaknesses which are representative, in my opinion, of the broader issues of how academia is dealing with the CAM phenomenon.

The Case for Science-Based Medicine

Before we get to the statement, let me review my position on the matter. As many readers will likely know, I am a strong advocate for what I call science-based medicine. The SBM approach, at its core, is simple – we advocate for one science-based standard for the health-care profession. This means that treatments which are safe and effective are preferred over those that are either unsafe or ineffective. Effectiveness and safety, of course, occur on a continuum and so individual decisions need to be made based on an overall assessment of risk vs benefit.

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Nov 06 2017

US Government Report Affirms Climate Change

climate changeThe U.S. Global Change Research Program Climate Science Special Report was recently published, and its conclusions are crystal clear:

 This assessment concludes, based on extensive evidence, that it is extremely likely that human activities, especially emissions of greenhouse gases, are the dominant cause of the observed warming since the mid-20th century. For the warming over the last century, there is no convincing alternative explanation supported by the extent of the observational evidence.

That conclusion is nothing new to those following the science of climate change for the last couple decades or so. The more this question is studied, the more data is gathered, the firmer the conclusion becomes – the planet is warming due to human release of greenhouse gases, such as CO2. There are error bars on how much warming, and the exact effects are hard to predict, but that’s it. The probable range of warming and effects are not good, however. It will be bad, the only real debate is about how bad and how fast.

The conclusions of the report, therefore, at least scientifically, are not surprising. It was, however, politically surprising. The special report began in 2015, under Obama. Because of Trump’s stated position that global warming is a Chinese hoax, and his appointment of many global warming deniers to key positions, it was feared that his administration would slow or frustrate the publication of this report.

However, according to the NYT, Trump himself was simply unaware of the report. Further, the fate of the report was largely in the hands of those amenable to following the science, rather than putting a huge political thumb on the scale. As a result the report was not hampered or altered. It was approved by 13 agencies who reviewed its findings.

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Nov 03 2017

Consistency Bias

Published by under Neuroscience

“Oceania was at war with Eurasia; therefore Oceania had always been at war with Eurasia.”

– George Orwell

persistence-of-memory-486x309In Orwell’s classic book, 1984, the totalitarian state controlled information and they used that power to obsessively manage public perception. One perception they insisted upon was that the state was consistent – never changing its mind or contradicting itself. This desire, in turn, is based on the premise that changing one’s mind is a sign of weakness. It is an admission of prior error or fault.

Unsurprisingly our perceptions of our own prior beliefs are biased in order to minimize apparent change, a recent study shows. The exact reason for this bias was not part of the study.

Researchers surveyed subjects as to their beliefs regarding the effectiveness of corporal punishment for children. This topic was chosen based on the assumption that most subjects would have little knowledge of the actual literature and would not have strongly held beliefs. Subjects were then given articles to read making the case for the effectiveness or ineffectiveness of spanking (either consistent with or contrary to their prior beliefs), and then their beliefs were surveyed again.

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Nov 02 2017

The Long Winter That Killed the Dinosaurs

Published by under General Science

ChixulubThere is still a bit of a debate about what, exactly, was responsible for the extinction of the non-avian dinosaurs and 75% of all species on Earth about 65 million years ago (the K-Pg extinction event). There is no question that a large meteor impacted near Chicxulub crater in the Gulf of Mexico at precisely that time, and was certainly responsible for at least some of the extinction. However, volcanism near the Deccan traps in India was also stressing the environment and may have contributed to some degree to the extinction. The debate is really about the relative contribution of these two factors, plus a potential third factor, marine regression.

As a non-expert enthusiast my reading of the consensus of scientific opinion is that the meteor impact was the main cause, perhaps made a bit worse by the pre-existing stressors which were already causing a minor extinction of their own. But the K-Pg event would not have been a mass extinction without the meteor strike.

Adding to this view is a recent analysis that indicates the impact would have caused a devastating continuous subfreezing “winter” from 3-16 years long, enough to make the Starks shiver (sorry for the gratuitous GOT reference). Scientists have been drilling in the Chicxulub crater to learn more about the specific effects of the impact.

I wrote in May of this year that scientists have discovered that the impact threw up large amount of gypsum (calcium sulfate dihydrate). The sulphur this would have thrown up into the atmosphere would have effectively blocked out the sun, reducing photosynthesis and breaking the food chain. The researchers even speculated that the impact was in the worst possible location, because the shallow seas have a lot of gypsum, which would not have been present on land or in deep ocean.

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