Eldritch Crank's List: science

R = h2 S.

R is the response to selection, S is the selection differential, and h2 is the narrow-sense heritability. This is the workhorse equation for quantitative genetics. The selective differential S, is the difference between the population mean and the mean of the parental population (some subset of the total population).

For example, imagine a set of parents with IQs of 120, drawn from a population with an average IQ of 100. Suppose that the narrow-sense heritability (in that population, in that environment) is 0.5 . The average IQ of their children will be 110. That’s what is usually called regression to the mean.

The fact that human evolution has been recent, copious, and regional is not widely recognized, even though it has now been reported by many articles in the literature of genetics. The reason is in part that the knowledge is so new and in part because it raises awkward challenges to deeply held conventional wisdom.

“What’s really going on is things are becoming more correlated with each other,” Lloyd recalls realizing. “The arrow of time is an arrow of increasing correlations.”

After years of failed attempts, researchers have successfully generated stem cells from adults. The process could provide a new way for scientists to generate healthy replacements for diseased or damaged cells in patients

Now there is hope in the form of new genome-engineering tools, particularly one called CRISPR.

In the past fifty years two large branches of physical science have each made a historic transition. I recall both cosmology and elementary particle physics in the early 1960s as cacophonies of competing conjectures. By now in each case we have a widely accepted theory, known as a “standard model.”

Scientists like to think of science as self-correcting. To an alarming degree, it is not

In the past fifty years two large branches of physical science have each made a historic transition. I recall both cosmology and elementary particle physics in the early 1960s as cacophonies of competing conjectures. By now in each case we have a widely accepted theory, known as a “standard model.”

The finger’s cells, bone, soft tissue, even nail grew into the mold. “It’s very interesting to see a patient heal. That’s my passion, wound healing. It is fascinating to have the new results,” said Dr. Rodriguez

Frankland suspected that memories actually got filed away into long-term storage, but that the hippocampus lost track of where they’d been stacked during the rapid growth phase that takes place in the first few years of life.

Entropy gets to the actual (rather than ideal) information content of a message by taking into account actual frequencies of usage of symbols. If English text used all letters of the alphabet equally (and unpredictably), then the entropy of text would be exactly 4.7 bits per symbol. Each symbol would contribute 1/26th of -log2(1/26) to the total. But because some letters are used more or less frequently than others, they contribute more or less than 1/26th of log2(1/26), and that total can add up to less than 4.7.

It's easy to visualize this with a simple example involving coin-tossing. Suppose, for sake of example, that a series of coin tosses comprises a message. As a medium of communication, the coin toss is capable of expressing only two states: heads, or tails. This could be represented in binary form as 1 and 0. If half of all tosses are heads and half are tails, then the total entropy in the message is 0.5 * log2(0.5) for heads plus 0.5 * log2(0.5) for tails, or one bit per symbol (Note: If you actually do the math you'll come up with a negative-1. Hence, in entropy calculations, the result is usually multiplied by -1 so it can be expressed as a positive number.)

Since most of the variation in IQ is heritable, scientists have long searched for genetic differences that might account for it. The reason we haven’t found them, Hsu theorizes, is because there aren’t any single genes or even a handful of genes with a big effect on IQ. Instead, the thinking goes, there are as many as 10,000 different locations in the genome where a mutation can affect IQ. According to Hsu’s rough model, all humans carry a few hundred of those 10,000 possible mutations, and each mutation has a tiny negative cost to IQ, on the order of half an IQ point.

Wells suggests they could take the technology further and use it to check for any serious inherited disorders at the same time as doing the chromosome check.

well done

Japanese scientists have produced 26 generations of clones from a single mouse, the lead researcher said Friday, possibly paving the way for the mass replication of valuable livestock.

The team have so far produced 598 mice that are genetic copies of one original creature in an experiment that has so far been going for seven years, said Teruhiko Wakayama of the Riken Center for Developmental Biology.

The very odd thing is that “if a slinky is hanging vertically under gravity from its top (at rest) and then released, the bottom of the slinky does not start to move downwards until the collapsing top section collides with the bottom.”

In the first test, Figaro tried unsuccessfully to reach the nut with a stick that was too short.

He then made his own tool by biting large splinters from a wooden beam. When they were the right size and shape to use as a "raking" tool, he would use them to successfully collect the nuts.

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The prospect of being able to create our own meat could herald a food revolution. Humanity’s meat consumption is projected to double in the next 40 years, according to the UN’s Food and Agriculture Organisation. Given that 70 per cent of agricultural land is already used for meat production, this could precipitate a food crisis of unimaginable proportions.

Jaroslav Flegr is no kook. And yet, for years, he suspected his mind had been taken over by parasites that had invaded his brain. So the prolific biologist took his science-fiction hunch into the lab. What he’s now discovering will startle you. Could tiny organisms carried by house cats be creeping into our brains, causing everything from car wrecks to schizophrenia?