Archive for April, 2018

Apr 10 2018

More Evidence Against Learning Styles

Published by under Education

Are you a visual learner or an auditory learner? Perhaps you learn best when studying material hands on. Or perhaps it doesn’t matter, and the entire concept of different people having different learning styles is not valid.

A new study adds to the pile of those that find little evidence to support the notion of learning styles, but we’ll get to that shortly.

The basic concept is that different people have different strengths and weaknesses that relate directly to how well they learn new information. Further, these strengths and weaknesses can be codified into specific styles, that can then be measured in some valid way. Finally, if you teach a student material in their preferred style, their outcomes will be superior to if they are taught the same material in a manner not in line with their preferred style.

Layered on top of this basic concept are different hypothesized schemes of learning styles – different ways to break up learning strategies. There are visual vs verbal learners, or perhaps abstract vs personal, more or less interactive, problem-solving, etc. One researcher estimated that there are more permutations of different learning styles than there are people on Earth. So really we have to ask – is the basic concept of learning styles valid, and if so which learning style scheme is more helpful?

The answer appears to be no and none.

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Apr 09 2018

Ecomodernism and Science-Based Environmentalism

I have always considered myself an environmentalist, but never found common cause with the environmentalist movement. The problem was (and remains) that so much of the environmentalist movement seems to be at odds with science.

Not always, of course. When the science agrees with a pro-environmentalist position, like the consensus on human-caused global warming, then environmentalists happily cite the science and link arm-in-arm with scientists. However, when the science does not align with the environmentalist position, such as with farming practices, GMOs, and nuclear energy, they just as happily take an anti-scientific position. Then scientists are in the pocket of big industry, the science cannot be trusted, and they cherry pick only the science they like.

So I like to think of myself as a science-based environmentalist. Even if you set aside the moral dimension and take a purely selfish point of view (I don’t, but even if you do), who wants to live on a planet that is all concrete and farmland? I love nature and wildlife, and I think most people do. Nature makes people happy.

No one wants to live on a polluted planet either. Pollution lowers quality of life and causes substantial health problems and cost.

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Apr 05 2018

Humans Are Still Evolving

Published by under Evolution

We tend to think of evolution as something that occurs over very long timescales – thousands and millions of years. While it is true that big changes require a long time, smaller changes must be occurring on shorter timescales. It is those small changes that accumulate into the bigger changes.

However, it’s difficult to perceive and measure the smaller changes that occur over short periods of time. Those small evolutionary changes can also be lost in the background noise of natural variations in a population.

What we need are techniques for observing populations in greater detail, so we can track evolutionary shifts. A 2016 study demonstrates a technique for doing just that. The researchers are taking advantage of the age of big data, in this case genetic data. There are now large genomic data sets available, and researchers can plow through that data to look for the telltale signs of evolutionary change, even over as little as a generation.

The authors of the current study developed a technique in which they count single base pair mutations near alleles (an allele is one copy of a gene – we have two copies or alleles of each gene, one from each parent). When genes are spliced together during recombination (the process by which alleles from each parent are randomly assembled into the genome of an egg or sperm) DNA near each allele will tend to go along for the ride. So that nearby DNA can be used to track the history of the allele itself.

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Apr 03 2018

Fermi vs Drake

Published by under Astronomy

In the world of Dune, human civilization about 10,000 years in the future had colonized the galaxy, with an empire spanning a “million” worlds. There were no aliens to get in our way, so once we had the technology for interstellar travel, we spread out. The first Dune novel was published 15 years after Fermi made his famous observation – essentially, if aliens exist, where are they? Why haven’t they colonized the galaxy like the humans in Dune?

More than half a century later, the Fermi Paradox remains a hotly debated mystery. One might also invoke the Drake Equation in this discussion. I often hear the Drake Equation dismissed as pseudoscience, but it is just a thought experiment. It is an equation that can be used to calculate the number of technological civilizations in the universe by plugging in all the relevant variables Рnumber of stars, then planets, then planets with life, than life that evolved intelligence, etc.  The only thing that can be considered pseudoscience is plugging in numbers that are just guesses and pretending they are scientific estimates.

The Drake Equation

We have started to make progress informing the variables in the Drake Equation, however. Astronomers have a pretty good handle on how many stars there are in the observable universe. Current estimates are that there are about 2 trillion galaxies in the observable universe, with an average of about 100 million stars per galaxy – 200 quintillion stars. We could be off by an order or magnitude or two, either way that is a massive number.

However, many people are interested in the subquestion Рhow common is intelligent life in the Milky Way galaxy? Therefore, how many stars are there in the Milky Way?  Estimates vary there as well, but it is on the order of 100 billion (could be several hundred billion).

After estimating the number of stars, further estimates in the Drake Equation get immediately dodgy. What we need to know next is how many stars have planets, and what is the typical distribution of planets by size and distance from their host star. In other words, how many stars have planets that can potentially host life? This is further complicated by the fact that we can only guess at how adaptable “life” is. Can life develop under the ice of large moons of gas giants? How about in the upper atmospheres of those gas giants?

It is easier, therefore, to answer the question – how many Earth-like planets are out there?

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Apr 02 2018

Science and Pseudoscience of the Interstitium

Recently scientists published a study in which they present evidence for a new possible organ called the interstitium. The science here is interesting – the interstitium is a distributed system of fluid filled cavities in the connective tissue. The fluid is lymph, which means that these cavities likely play an important role in the immune system. They also give the skin and connective tissue a spongy structure, which would make them more flexible and durable.

It is also interesting how the existence of the interstitium was missed for so long. It was an artifact of the methods used to prepare tissue for slides. Fixing the tissue with chemicals would dry out the tissue, causing the cavities to collapse. It was therefore thought that these connective tissue layers were solid.

The science here seems solid, and will likely lead to further discoveries that might inform our understanding of certain diseases. However, the authors of the study decided to spread some pseudoscience along with the science.

Neil Theise, professor of pathology at NYU School of Medicine, and Rebecca Wells, professor of medicine and bioengineering at University of Pennsylvania, on a segment of Science Friday where they discuss their study, said that the interstitium might explain how acupuncture works. Some news outlets even decided to lead with the acupuncture angle. In an article for The Cut Theise digs deeper:

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