Daniel Lemire's blog

, 5 min read

Science and Technology links (September 1st, 2018)

  1. What causes the obesity epidemic? Archer et al. think the role of diet is overblown. Rather they believe that obesity is caused by reductions in physical activty below the Metabolic Tipping Point. Their argument is based on the fact that various human population have had various diets (including diets rich in sugar) without triggering widespread obesity. Of course, one would need to demonstrate that physical activity has declined recently. My impression is that many people, being overweight, try to exercise more… without necessarily losing weight.

Update: Archer clarified his position by email:

To be precise, the major determinant of the obesity and diabetes epidemics was the loss of matrilineal and maternal metabolic control due to low levels of physical activity (PA) during the pubertal, pre-conception, and prenatal periods. Yet PA only needed to be lower in previous, not current generations.

The non-genetic evolutionary processes of maternal effects, phenotypic evolution and accommodation (i.e., a form of canalization) allow the recapitulation (inheritance) and/or evolution of obese and metabolically compromised phenotypes without the original environmental context (i.e., low physical activity). In other words, after a few generations of offspring being born less metabolically robust, each successive generation would need to eat less and move more than the previous generation to remain at the same level of adiposity.

  1. A disproportionate number of Thai Buddhist monks are overweight.
  2. Rapamycin is a common drug given to transplantees. It seems that Rapamycin is capable of rejuvenating overaries, and thus prolong fertility in females. It works in mice.
  3. Paul Krugman, a celebrated economist and Nobel-prize recipient, predicts the fall of Bitcoin:

there might be a potential equilibrium in which Bitcoin (although probably not other cryptocurrencies) remain in use mainly for black market transactions and tax evasion, but that equilibrium, if it exists, would be hard to get to from here: once the dream of a blockchained future dies, the disappointment will probably collapse the whole thing.

My wife might make peace with the fact that some nice people once granted me a bitcoin (circa 2012), that I quickly discarded without any thought.

  1. Taleb on innovation (in his book Antifragile):

both governments and universities have done very, very little for innovation and discovery, precisely because, in addition to their blinding rationalism, they look for the complicated (…) rarely for the wheel on the suitcase. Simplicity does not lead to laurels. (…) Even the tax-funded National Institutes of Health found that out of forty-six drugs on the market with significant sales, about three had anything to do with federal funding.

  1. Of the social science studies published in Nature and Science, about a third cannot be reproduced. More critically, the effect being reported is half as large as it should be in the other studies.
  2. Daily aspirin may not help reduce cardiovascular risks. The study is strong with many participants, but there are possible problems like low adherence and insufficient dosage. My understanding is that aspirin may only help if the dosage is just right (not too high, not too low).
  3. Daily aspirin reduced deaths due to several common cancers. Benefit increased with duration of treatment and was consistent across the different study populations.
  4. Statins are regularly prescribed to people at risk of heart attacks or strokes. It is a billion-dollar industry. Okuyama et al. report that statins stimulate atherosclerosis and heart failure.
  5. Few animals have menopause. Besides human beings, it seems that a few whales also have menopause. That is pretty much all.
  6. Common viruses might put you at risk for Alzheimer’s.
  7. The co-inventor of deep learning, Hinton, writes:

The data efficiency of deep learning will be greatly augmented in the years ahead, and its potential applications in health care and other fields will increase rapidly.

  1. The CEO of a company backed by Amazon’s Jeff Bezos is quoted by CNBC as saying:

The time has finally arrived that our knowledge of biology and our sophistication level is sufficient that we can attack some of these fundamental, underlying causes of aging

  1. Dairy products protect you from death.
  2. C++ is a popular programming language, especially among videogame developers. I like C++ well enough when the programmers try to avoid fancy features and unnecessary abstraction. However, I have increasingly felt uneasy about the language as it seems to attract people who believe that complexity is a feature. Scott Meyers, a reputed author of books on C++ writes:

C++ is a large, intricate language with features that interact in complex and subtle ways, and I no longer trust myself to keep all the relevant facts in mind. As a result, (…) I no longer plan to update my books to incorporate technical corrections

I am not sure we should take Scott litterally. I think he may very well be able to figure out what the C++ standard says, but he might have concluded that the interaction with people who enjoy the complexity a bit too much is too annoying.

Here is Linus Torvalds on C++:

(…) the only way to do good, efficient, and system-level and portable C++ ends up to limit yourself to all the things that are basically available in C. And limiting your project to C means that people don’t screw that up, and also means that you get a lot of programmers that do actually understand low-level issues and don’t screw things up with any idiotic “object model” crap.

If you read Linus carefully, his objection regarding C++ stems from the kind of people who are attracted to the language.

As I repeatedly write: programming is social.