Daniel Lemire's blog

, 3 min read

Science and Technology links (July 21st, 2017)

Want proof that you live in the future? Ok. There is this “cryptocurrency” called ethereum and it is causing a shortage of microprocessors:

Demand from Ethereum miners has created temporary shortages of some of the graphics cards, according to analysts, who cite sold-out products at online retailers. Estimates of additional sales from this demand run as high as $875 million, according to RBC Capital Markets analyst Mitch Steves. That would roughly equal AMD’s total sales from graphics chips last year, or half of Nvidia’s quarterly sales of those components.

This is all very strange.

It is not exactly known why hair turns gray as well age, but it is largely reported as an irreversible process linked with cells dying out. Yet time and time again, there are anecdotes of graying reversal. The latest one was published in a reputable journal (JAMA Dermatology) that even tweeted a picture. In that report, 14 cancer patients have seen their hair pigmentation come back. That offers a powerful hint that we could reverse gray hair with the right therapy. Obviously, there are cheap and obvious ways to turn your hair any color you like at any age… but such reports remind us that there is much we do not understand yet.

Intel’s latest chip, the Core i9 X-series, can produce one teraflop of computing performance for about $2000. If you have 2 billion dollars, you can theoretically buy a million of these chips and produce the first exascale supercomputer. Of course, you’ll also cause a massive power shortage in your neighborhood if you ever turn the thing on.

Jeff Bezos, the president of Amazon, is 53, and so he was in his early 30s when he started out his business. A picture of him offering a side-by-side comparison, 20 years ago and today, has been widely distributed. I would not contradict the current Jeff Bezos: he looks like he could break me in half.

Our brains are poor at repairing themselves. There is such a thing as in vivo neuroregeneration, but it is not widespread in the human body. Researchers have found that using by using the right electrical field, they could entice stem cells to relocate where repairs are needed and then differentiate appropriately. We all know that we inherit our genes from our parents. Then our cells turn on or off those genes through a set of poorly understood techniques called epigenetics. This is necessary if only for cell differentiation: the cells from your brain have the same genes as the cells from your toes, but they express different genes. The older version of you has the same genes as the younger version, but the older you express more genes. It is believed that lifestyle can affect genes. If you starve all your life or exercise intensively, you will express different genes. But can this program of gene expression be passed on to your children? It seems that you can, at least in some specific ways. A recent article in Science makes a case for it:

Parents provide genetic information that guides the development of the offspring. Zenk et al. show that epigenetic information, in the form of the repressive mark H3K27me3, is also propagated to the offspring and regulates proper gene expression in the embryo. Preventing the propagation of maternally inherited H3K27me3 led to precocious gene activation and, ultimately, embryo lethality.

In the early days of the XIXth century, there was debate as to how species evolved. How did the giraffes get long necks? The commonly accepted view is that of Darwin: giraffes with longer necks tended to survive longer and to have more offsprings so that over time, giraffes acquired longer and longer necks, one generation at a time. There were theories that predate Darwinism, one of them by Jean-Baptiste Lamarck. Lamarck believed in soft inheritance. For example, he would believe that if your parents are body builders, you would inherit larger muscles. Lamarck’s view is now discredited, but if epigenetic markers can be passed on to offsprings, then we would be forced to conclude that he was partly right. If you follow the logic of the Science article, it is conceivable that in a society of bodybuilders, kids could receive epigenetic markers that enhance muscle growth. I should point out that even if epigenetic markers are passed on, this does not put into question Darwinism: at best, Darwinism is an incomplete theory.