11th March 2023, 4 min read

Science and Technology links (March 11 2023)

In 1500, China was the largest economy in the world, followed by India and France. The USA did not exist yet. In 1700, 4% of human beings lived in France. In the mid 18tg century, there are 25 million inhabitants in France and 5.5 million in England. Yet France had slipped to a sixth place as an economic power worldwide, while the United Kingdom moved up. It was beginning a sustained decline. So what happened to France? It appears that decades before the French revolution, France became less religious and that was the driver for a large decrease in fertility.
Men who do physical labor have higher sperm counts and testosterone levels.
You can take human brain cells, put them in a rat, and these cells will integrate into the rat’s brain.
The top 1 per cent in income score slightly worse on cognitive ability than those in the income strata right below them according to Keuschnigg et al. (2023).
Both hemispheres (south and north) absorb the same amount of energy from the Sun. According to Hadas et al., the presence of more ocean causes the southern-hemisphere to absorb more sunlight; however, it also makes it stormier, increasing cloud-albedo and balancing the difference in reflected sunlight. In effect, the atmosphere is balancing out greating forcing.
Half of elderly American men take statins. In patients suffering from Alzheimer’s, statins worsen cognition: after stopping statins, the patients improved.
Though earlier research concluded that happiness increases with income only up to a point, Killingsworth et al. (2023) find there is a robust linear-log relationship between income and happiness, meaning that each time you multiply your income, your happiness goes up a level. Note that this is a relationship, not necessarily a causal effect.
Sea levels were about 1.5 meters higher 6000 years ago.
High-intensity acute exercise enhances memory.
According to the CDC, 13% of all Americans take antidepressants at any given time. About 15% of patients taking antidepressants have an effect that is above the placebo effect. In other words, most people take antidepressants for no benefit. But antidepressants may not be without risks. Antidepressants are associated with dementia: they may put you more at risk for Alzheimer’s.
Despite substantial reductions in anthropogenic CO₂ emissions in early 2020, the annual atmospheric CO₂ growth rate did not decline, according to Laughner et al. (2021). They write:

The lack of clear declines in the atmospheric growth rates of CO₂ and CH₄, despite large reductions in human activity, reflect carbon-cycle feedbacks in air–sea carbon exchange, large interannual variability in the land carbon sink, and the chemical lifetime of CH₄. These feedbacks foreshadow similar challenges to intentional mitigation.

By using the blood of a young mouse in a old mouse, we appear to be able to at least partially rejuvenate the brain of the old mice.
The gas H2S increased longevity in worms.
The energy density of Li-ion batteries has increased by less than 3% in the last 25 years according to Li (2019).
There were giant penguins during the Paleocene. They might have weighted 150 kg, for more than most human beings. The climate during the Paleocene was generally tropical and the poles were ice-free.
Young men sometimes outperform young women in standardized mathematical tests, while the opposite is true in some other domains. The gap is larger in gender-equal countries.
There are still compulsory sterilization laws in the USA: the State may legally require your sterilization.
We used to think that the earliest human beings (homo sapiens) migrated out of Africa 120,000 years ago. However, we found fossils as old as 177,000 years. The oldest fossils were found in Morocco (315,000 years old), though there are some doubts whether they were from homo sapies.
It appears that ChatGPT is biased against conservative politicians. One might expect the system to express the biases of its creators.