Archive for October, 2017

Oct 19 2017

More Gravitational Waves

Published by under Astronomy

neutronStar_drupal_withNOcaptionThe winner of the Nobel prize for physics was the detection of gravitational waves. These are extremely subtle ripples in spacetime caused by massive cataclysmic events, such as black holes colliding. These ripples were predicted by Einstein, who thought we may never be able to detect them because they would be so unbelievably tiny.

How tiny?  LIGO (Laser Interferometer Gravitational-Wave Observatory), the device used to detect the waves, can detect changes as small at 10 -22 meters. Graviational waves detected so far have had an amplitude of 10 -18 meters, smaller than the radius of a proton.

How is that possible? That is where the interferometry comes in. LIGO uses a laser split into two beams that will travel for 8 Km and then reflect off mirrors and come back to the same detector. The two beams have traveled the exact same distance so that they are in phase, or at least they can be calibrated to be exactly in phase, meaning that the peaks of the waves line up. When a ripple in spacetime comes through, the length of the two arms (which are at 90 degree angles to each other) will change slightly, bringing the two beams out of phase. That slight phase shift can be detected and measured.

Prior to winning the Nobel prize LIGO had detected four gravitational waves wash over it. This was considered enough of a confirmation of the technology and science to award the prize.

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Oct 17 2017

What Is Artificial Intelligence

AI-1A recent article by Peter Yordanov claims that Artificial Intelligence (AI) is nothing but misleading clickbait. This is a provocative way to state it, but he has a point, although I don’t think he expressed it well.

Yordanov spends most of the article describing his understanding of human intelligence, partly by walking through the evolution of the central nervous system. His basic conclusion, if I am reading it correctly, is that what we have today and call AI is nothing like biological intelligence.

This is certainly true, but it seems like he takes a long time to make what is essentially a semantic argument. The core problem is that the word “intelligence” means many things. Lack of a consistent operational definition plagues the use of the term is pretty much every context, and certainly in computer AI.

What we have now and is generally referred to as AI are computer algorithms that display functions that resemble intelligence or duplicate certain components of intelligence. Computers are good at crunching numbers, running algorithms, recognizing patterns, and searching and matching data. Newer algorithms are also capable of learning – of changing their behavior based on data input.

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74 responses so far

Oct 16 2017

Clean Eating Antiscience

Eating “clean” is the latest fad diet pseudoscience. A recent article in The Guardian goes over the many aspects of this movement in great detail, and is worth a read. My only complaint is that the author, Bee Wilson, buys into misinformation about the medical profession and nutrition.

Wilson claims that the medical profession was unhelpful when it came to nutrition. I disagree – the medical profession was at the forefront of nutritional research and advice. The problem was that the science-based answers were not what everyone wanted to hear.

There are many aspects to the clean-eating movement, which Wilson does do an excellent job discussing. It is mostly marketing, a way for self-proclaimed “gurus” to make millions selling cookbooks, diet plans, and detox programs with outrageous claims that it will transform you health and cure whatever ails you.

The movement is also partly a reaction to the realities of modern Western culture. There is an obesity epidemic in our culture, and while the exact causes are debated it seems clear that the food industry is partly to blame. Market forces also favor tasty food, which tends to be calorie dense, and supersized portions.

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Oct 13 2017

A Poor Marker of Truth

Published by under Culture and Society

lunar animalsAs a recent Atlantic article recounts, in the early 1800s steamed powered printing presses were making the distribution of information cheaper and faster. It didn’t take long for someone to figure out that this was an opportunity. In 1833 Benjamin Day (who was just 23 – the Zuckerberg of his age) founded the New York Sun.

The paper was the first of the “penny press” – sold for just a penny to increase distribution, and then monetized through advertising. This was a new paradigm – Day was not really selling information to the masses, he was selling the attention of the masses to advertisers. This flipped the incentives. He no longer had an incentive to produce quality information (because information was not the product), but rather to print whatever information got the most attention (which was his product).

So, in 1835 Day printed a series of stories about how astronomers, using a new telescope, were seeing bat people on the moon. The story “went viral” and fooled most people. It took rival newspapers to debunk the stories until Day finally admitted the whole thing was a hoax. That hoax may have been over, but it spawned an age of tabloids that continues to this day.

The printing press of the 21st century, of course, is the internet, and attention is the coin of the realm. This creates an inherent dilemma for our society – because attention is a poor marker of truth.

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Oct 12 2017

Another Antivaccine Retraction

Retracted-950x633Science only works when it works.

In other words – science itself does not lead to an understanding of the universe unless that science is done correctly, rigorously, and honestly. This is a lot harder than I think is generally appreciated. In order to really reach firm scientific conclusions about any complex question we need to follow the arch of the research as it matures. We need to see what overall patterns emerge in the evidence. Eventually a tentative but reliable scientific consensus can be achieved.

There are many ways in which this process can go off the rails, however. With ESP we see researchers chasing the noise – trying to find tiny signals but only chasing their tails. With acupuncture we see proponents choosing to ignore, misinterpret, and then abandon well-controlled clinical trials in favor of “pragmatic” studies that will show them what they want. There is “cargo cult” science that goes through the superficial motions but lacks true scientific methodology. There is “Tooth Fairy” science that nibbles around the edges but never addresses the core premise – is the phenomenon actually real?

There is a huge positive bias in science – researchers have a tendency to tweak their methods to get the results they want, publishers have a tendency to publish positive exciting research, and other scientists have a bias toward citing positive interesting research. Funding sources affect research outcome. When pharmaceutical companies fund research the results are much more likely to be favorable to their drug than independent research. Scientists make mistakes, take shortcuts, and often have blinders on. And then there is outright fraud, which is uncommon but still crops up on a regular basis.

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Oct 10 2017

Half the Matter in the Universe Just Found

Published by under Astronomy

filamentsBy now most people are familiar with dark matter – that mysterious substance which has gravity but otherwise does not seem to interact with the normal matter with which we are most familiar. About 27% of the stuff (matter and energy) in the known universe is dark matter, 68% is dark energy, and only about 5% is made of known particles (baryons – protons, neutrons; leptons – electron; and more exotic particles).

We currently don’t know what dark matter is. We know it’s there because we can see its gravitational effect, first noticed because galaxies spin faster than they should. Based just on the gravity from stuff we can see, galaxies should be flying apart. They stick together because there is significantly more gravity than we can account for. There must be additional matter we can’t see, or dark matter.

It is perhaps less well-known that we also haven’t found about half of the normal matter that should exist in the universe. Even if we just consider that 5% that is made of standard particles, about half of it is missing. That is – until now, if recent reports are accurate.

This really wasn’t much of a mystery (not like dark matter) – astronomers suspected that the missing matter was present in the form of diffuse gas between galaxies. There is a lot of space out there, and even a wispy vapor could contain a lot of particles, as much as is contained in all the visible galaxies. The problem is, this thin gas is too wispy to see with conventional means.

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16 responses so far

Oct 09 2017

The Perfect is the Enemy of the Good

Published by under Logic/Philosophy

Voltaire-quoteThis aphorism has been around since about 1600, originating with Voltaire in French. I have found it to be a useful concept – not an iron-clad rule, but an excellent guiding principle. The perfect is the enemy of the good (sometimes “good enough”).

What this means is that we should not be paralyzed into inaction because we cannot achieve a perfect solution to a specific problem. The idealized perfect solution becomes an obstacle to solutions that are adequate, or at least an improvement on what we have now.

In reality this can be a tricky principle to apply, however. Like the informal logical fallacies, or any informal guideline for clear thinking, there are no rigid rules or definitions. Judgement is required, which means that subjectivity and bias are also involved.

There are two specific ways this principle is either applied to not applied that tends to come up with skeptical topics. The first deals with our own activism – when should we apply this principle?

For example, over the years I and some of my medical colleagues have had a disagreement about how best to approach topics like vaccine exemptions. We all agree that non-medical exemptions decrease vaccine compliance and are a threat to public health. We all agree that in a perfect world states would not allow non-medical exemptions (only exemptions for children who medically are unable to be vaccinated).

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Oct 06 2017

Unnecessary Medical Interventions

clinical-decision-making-46-638A recent JAMA article is an update on a systematic review of overused interventions in medicine. They list the top ten overused tests and treatments, meant to highlight this problem in medicine. They conclude:

The body of empirical work continues to expand related to medical services that are provided for inappropriate or uncertain indications. Engaging patients in conversations aimed at shared decision making and giving practitioners feedback about their performance relative to peers appear to be useful in reducing overuse.

You can read a summary of the ten overused interventions here.  The one you are likely already familiar with is antibiotic overuse. The others are very specific tests or interventions in specific situations, like Computed Tomography Pulmonary Angiography to help diagnose acute pulmonary embolism.

Reviewing each of these interventions in the top ten list would require a deep dive into the literature and detailed discussion, which is not my intent here. If you want that level of detail, read the original article. What I want to discuss is, in general terms, why this is a problem in the first place.

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Oct 05 2017

The Gun Debate Revisited

Published by under Culture and Society

Gun-deathsAfter every mass shooting there is a renewed debate and call for better gun control, and pushback from gun owners who say, “Now is not the time to get political,” and “There’s nothing we can do to stop gun violence, it’s the price of freedom.” Then precisely nothing happens until we get distracted by something else and forget about gun violence until the next headline-grabbing shooting.

Clearly whatever we are doing is not working, and it is the oft-cited definition of insanity to do the same thing and expect a different outcome. So what are we doing wrong?

First, we have to acknowledge that there is a problem. There are about 33,000 gun deaths per year in the US. This is more than any other wealthy country – only war-torn banana republics have higher rates of gun deaths. There were 477 mass shootings in the US in 2016.

About two thirds of gun deaths are from suicides. That is a large portion, but that still leaves 11,000 non-suicide gun deaths each year in the US. Gun homicides are a huge problem, not diminished at all because gun suicides are an even bigger problem. About 20% of gun deaths are crime and gang-related homicides, mostly young men killing other young men. Also, about 1,700 women are killed each year from gun-related domestic violence.

I reject the notion that this is the best we can do, that this is the price of freedom. Other Western democracies seem to enjoy freedom without anything close to the same rate of gun violence. So why has this been such a hard problem to solve?

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111 responses so far

Oct 03 2017

Nobel in Medicine for Circadian Rhythm

Published by under General Science

Nobel 2017-MedicineRemember that time Sarah Palin said:

“[tax] dollars go to projects that have little or nothing to do with the public good — things like fruit fly research in Paris, France. I kid you not.”

OK, she was actually referring to the olive fruit fly, Bactrocera oleae, not the staple of genetics research, Drosophila melanogaster. The comment is still a legitimate target for criticism because it is not clear that Palin understands the difference (or she wouldn’t have said it that way), her statement seems to imply that scientific research into the humble “fruit fly” is a waste, and she is generally anti-science (when it conflicts with her ideology).

At the time of her statement many scientists and reporters delighted in pointing out how central fruit fly research has been to scientific advancements. Well, we can add another example from this year’s Nobel Prize in Physiology or Medicine. The prize goes to three American scientists, Jeffrey C. Hall, Michael Rosbash and Michael W. Young, for their work on the circadian rhythm.  Continue Reading »

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