Daniel Lemire's blog

, 2 min read

Science and Technology links (March 30th 2019)

  1. As we age, we accumulate old and useless (senescent) cells. These cells should die, but they do not. Palmer et al. removed senescent cells in obese mice. They found that these mice were less diabetic and just generally healthier. That is, it appears that many of the health problems due to obesity might have to do with the accumulation of senescent cells.
  2. Europe is changing its copyright laws to force websites to be legally responsible for the content that users upload. In my opinion, copyright laws tend to restrict innovation. I also think that Europe is generally not interesting in innovating: where is Europe’s Google or Europe’s Samsung?
  3. China is cloning police dogs.
  4. Do we create new neurons throughout life, or not? It remains a controversial question, but a recent article in Nature seems to indicate that neurogenesis in adult human beings is tangible:

By combining human brain samples obtained under tightly controlled conditions and state-of-the-art tissue processing methods, we identified thousands of immature neurons in (…) neurologically healthy human subjects up to the ninth decade of life. These neurons exhibited variable degrees of maturation (…) In sharp contrast, the number and maturation of these neurons progressively declined as Alzheimer’s Disease advanced.

  1. Generally speaking, the overall evidence is that fit and healty people tend to be smarter. It is a myth unsupported by science that the gym rat is dumb whereas the pale out-of-shape guy is smart.If you want to be smart, you better stay fit and healthy. Evidently, this suggests that as you age, you may become lose some of your intellectual sharpness.Cornelis et al. processed a large dataset of cognitive tests and they conclude that you are not losing your intelligence very much, at least until you reach a typical retirement age:

declines in cognitive abilities between the end of the fourth decade and age 65 are small.

In their experiments, fluid intelligence (basically our reasoning ability) did not change very much and sometimes increased over time. This apparently contradict other studies based on smaller samples, and the authors discuss this apparent contradiction. Reaction time increased with age: older people are slower, everything else being equal.