3rd November 2018, 3 min read

Science and Technology links (November 3rd, 2018)

1. Bitcoin, the cryptocurrency, could greatly accelerate climate change, should it succeed beyond its current speculative state.
2. Crows can solve novel problems very quickly with tools they have never seen before.
3. The new video game Red Dead Redemption 2 made $725 million in three days.
4. Tesla, the electric car company, is outselling Mercedes Benz and BMW while making a profit.
5. Three paralyzed men are able to walk again thanks to spinal implants (source: New York Times). There are nice pictures.
6. Human beings live longer today than ever. In the developed world, between 1960 and 2010, life expectancy at birth went up by nearly 20 years. It consistently goes up by about 0.12 years per year. However, it is not yet clear how aging and death have evolved over time. Some believe that there is a “compression” effect: more and more of us reach a maximum, and then we suddenly all die at around the same age. This would be consistent with a hard limit on human lifespan and I think it is the scenario most biologists would expect. There is also the opposite model: while most of us die at around the same age, some lucky ones survive much longer. According to Zuo et al. (PNAS) both models are incorrect statistically. Instead, the curve is advancing as a wave front. This means that as far as death is concerned, being 68 today is much like being 65 a generation ago. This is surprising.
   

(…) we find no support for an approaching limit to human lifespan. Nor do our results suggest that endowments, biological or other, are a principal determinant of old-age survival.

Assuming that Zuo et al. are correct, I do not think we have a biological model at the ready to explain this statistical phenomenon.

1. Suppose that you gave a cocktail of drugs approved for human consumption to worms. By how much do you think you could extend their lifespan? The answer is at least by a factor of two. They tried their best cocktails with fruit flies and showed benefits there as well. It is much harder to manipulate the lifespan of large mammals like human beings, but these results support the theory that drug cocktails could increase human lifespans. They may already being doing so.
2. Amazon is hiring fewer workers, maybe because it is getting better at automation. (speculative) It seems that Amazon is mostly denying the story, hinting that they are still creating more and more jobs.
3. No primate except for human beings, undergoes menopause. Very few animals have menopause: primarily some whales and human beings. I don’t think we know why menopause evolved.
4. Total direct greenhouse gas emissions from U.S. livestock have declined 11.3 percent since 1961, while production of livestock meat has more than doubled.
5. Male and female animals respond very differently to anti-aging strategies and they age very differently:
   

One particularly odd thing in humans is that though women live longer, they are nonetheless more prone to miserable but non-deadly ailments such as arthritis (…) Lethal illnesses such as heart disease and cancer strike men more often. Although Alzheimer’s strikes women more than men, for unknown reasons.

We do not know why there is such a sharp difference between males and females regarding health and longevity. However, some believe that the current historical fact that women live many years more than men is due to the fact that antibiotics disproportionally helped the health of women.

1. Vegans more frequently suffer from bone fractures.
2. Teaching by presenting worked examples seems to be most efficient. Students get the best grades with the least work.This appears self-evident to me. It is curious why worked examples are not more prevalent in teaching.
3. A company called Grifols claims to have a drug that can measurably slow down the progression of Alzheimer’s. For context, we currently have no therapy to slow or reverse Alzheimer’s, so even a small positive effect would be a tremendous breakthrough. However, there has been many, many false news regarding Alzheimer’s and this report appears quite preliminary.