Sep 17 2021

Spock vs Holmes

You’ve probably noticed that it’s very difficult to write a character who is extremely intelligent in some way. It’s easy to make a character knowledgeable, because you can just put a lot of facts into their mouth. The character Arthur P. Dietrich (played by Stephen Landesberg) on the sitcom Barney Miller always had a relevant fact at the ready. He seemed to know everything. What’s difficult is making a character wise, or giving them the ability to think in complex and logical ways. More specifically, it’s difficult to write a character that’s smarter than the writer themselves.

For me the most impressively written iconically smart character is Sherlock Holmes, written by Arthur Conan Doyle. It’s not impressive that Holmes always solved his cases or had a lot of factual knowledge; that’s the easy part. The author knows who did it and can just have their detective character get to the right answer. What is truly impressive is how Holmes worked through the cases, using genuinely impressive logic and reasoning. Holmes famously refers to his process as “deduction” but he was really mostly using inference to the most likely answer.

I admit I may be partial to Holmes because Doyle was a physician, and I can recognize a lot of clinical logic in Holmes’ thinking. In fact, I took a course on Sherlock Holmes in medical school, where we would make an analogy to how Holmes solved a particular case to how a physician might solve a clinical case. Here are some choice bits of logical advice from Holmes: Continue Reading »

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Sep 16 2021

Another Fusion Breakthrough

About a month ago I wrote about a milestone achieved by the National Ignition Facility (NIF) which is using the inertial confinement method to achieve fusion of hydrogen into helium. Briefly, they achieved “burning plasma” where heat from the fusion provides energy for further fusion. They are only about 70% of the way to ignition, where the fusion is self-sustaining with only its own energy.

The NIF uses lasers to compress the hydrogen plasma to sufficient heat and density for fusion to occur. The other approach to achieving fusion is magnetic confinement, using powerful magnetic fields to squeeze the plasma to incredible density and heat, so that the hydrogen atoms are moving fast enough that occasionally two will collide with enough force to cause fusion. The magnetic confinement approach is all about the magnets – if we have magnets that are powerful and efficient enough, we can make fusion. It’s that simple. After decades of plasma research there are multiple labs around the world that can use magnetic confinement to get hydrogen to fuse. But we have yet to achieve “ignition”. Also, ignition is not the final goal, just one more milestone along the way. We need to go beyond ignition, where the fusion process is producing more than enough energy needed to sustain the fusion, so that some of the excess energy can be siphoned off and used to make electricity for the grid. That’s the whole idea.

MIT’s Plasma Science and Fusion Center (PSFC) in collaboration with Commonwealth Fusion Systems (CFS) has their own magnetic confinement fusion experiment called SPARC (Soonest/Smallest Private-Funded Affordable Robust Compact). This is a demonstration reactor based on the tokamak design first developed by Soviet physicists. The magnetic field is a doughnut shape with a “D” shape in cross-section. Three years ago they determined that if they could build a magnet that was able to produce a 20 Tesla magnetic field, then the SPARC reactor would be able to produce excess fusion energy. It’s all about the magnets. The news is that they just achieved that very goal, on time despite the challenges of the intervening pandemic.

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Sep 14 2021

Cognitive Control and Cheating

It is a fundamental truth of human behavior that people sometimes cheat. And yet, we tend to have strong moral judgements against cheating, which leads to anti-cheating social pressure. How does this all play out in the human brain?

Psychologists have tried to understand this within the standard neuroscience paradigm – that people have basic motivations mostly designed to meet fundamental needs, but we also have higher executive function that can strategically override these motivations. So the desire to cheat in order to secure some gain is countered by moral self-control, leading to an internal conflict (cognitive dissonance). We can resolve the dissonance in a number of ways. We can rationalize the morality in order to internally justify the desire to cheat, or we can suppress the desire to cheat and get a reward by feeling good about ourselves. Except experimentally most people do not fall at either end of the spectrum, but rather they cheat sometimes.

Recent research, however, has challenged this narrative, that cheating for gain is the default behavior and not cheating requires cognitive control. A new study replicates prior research showing that people differ in terms of their default behavior. Some people are mostly honest and only cheat a little, while others mostly cheat, and there is a continuum between. Perhaps even more interesting is that the research suggests that for those who at baseline tend to cheat, markers of cognitive control (using an EEG to measure brain activity) increase when they don’t cheat and behave honestly. That’s actually not the surprising part, and fits the classic narrative that people tend to cheat unless they exert self-control to be honest. However, those who are more honest at baseline show the same markers of increased cognitive control when they do cheat. They have to override their inherent instinct in the same way that baseline cheaters do. What’s happening here?

Before I discuss how to interpret all this, let me explain the research paradigm. Subjects were tasked with finding differences between two similar images. If they could find three differences, they were given a real reward. However, some of the images only had two differences, so subjects had to either accept defeat or cheat in order to win. First subjects were tested at baseline to determine their inherent tendency to cheat. Then they were encouraged to cheat with the rigged games. EEGs were used to measure theta wave activity in specific parts of the brain, which correlates with the degree of cognitive control. Subjects who cheated more at baseline showed increased theta activity when they didn’t cheat, and those who were more honest at baseline showed increased theta activity when they cheated.

Therefore, it appears more accurate to say that cognitive control allows us not to do the morally “correct” thing, but to act against our instincts, whatever they are. But why would people have such different instincts in the first place?

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Sep 13 2021

Using Solar Power to Make Ammonia

Ammonia is the second most produce industrial chemical in the world. It is used for a variety of things, but mostly fertilizer:

About 80% of the ammonia produced by industry is used in agriculture as fertilizer. Ammonia is also used as a refrigerant gas, for purification of water supplies, and in the manufacture of plastics, explosives, textiles, pesticides, dyes and other chemicals.

In 2010 the world produced 157.3 million metric tons of ammonia. The process requires temperatures of 400-600 degrees Celsius, and pressure of 100-200 atmospheres. This uses a lot of energy – about 1% of world energy production. The nitrogen is sourced from N2 in the atmosphere, and the high pressure and temperatures are necessary to break apart the N2 so that the nitrogen can combine with hydrogen to form NH3 (ammonia). The hydrogen is sourced from natural gas, using up about 5% of the world’s natural gas production. About half of all food production requires fertilizer made using this process (the Haber-Bosch process). This is not a process we can phase out easily or quickly.

It does represent, however, a huge opportunity for increased efficiency, saving energy and natural gas, and reducing the massive carbon footprint of the entire process. We know it’s possible because bacteria do it. Some plants have a symbiotic relationship with certain soil bacteria. The plants provide nutrients and energy to the bacteria, and in turn the bacteria fix nitrogen from the atmosphere (at normal pressures and temperatures) and provide it to the plant. These plants (which include, for example, legumes) therefore do not require nitrogen fertilizer. In fact, they can be used to fix nitrogen and put it back into the soil.

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Sep 10 2021

New Spacesuits

One of the technologies that had to be developed in order to return to the Moon, and possibly go on to Mars, is spacesuits. It may seem like we already have developed adequate spacesuit technology, since we used them on the Moon during the Apollo missions, but this is not true. The Apollo suits were only designed to survive for days on the Moon, not for the much longer missions the Artemis program plans. They were also very clumsy, as you can tell from watching any Apollo footage of the astronauts.

Developing the next generation of spacesuits has proven more challenging than initially thought. Recently NASA announced delays in completing their Artemis spacesuits, which will be available no sooner than 2025, at a development cost of over $1 billion. If we managed to develop spacesuits usable on the Moon in the 1960s, why is this proving so challenging six decades later? Essentially it’s because our goals are more ambitious, but let’s review the challenges.

The Moon is a harsh environment, most obviously because it is a near vacuum. At a minimum spacesuits need to maintain sufficient pressure to keep astronauts alive and comfortable. Current suits use a pressure of 4.3 psi (pounds per sq inch). One atmosphere of pressure is 14.7 psi, which means the suits are pressurized to the equivalent of 30,000 feet altitude. You can compensate for the lower pressure by increasing the percentage of oxygen in the air mix. Why use such low pressure? Because this pressure causes the suit to be tight. At one full atmosphere of pressure the suit would be so tight the astronauts couldn’t move.

Another option is to use a skin-tight suit, with direct pressure on the skin. This would be a much skinnier suit and allow for greater movement, but such suits would be very expensive to build, and would have to be minutely customized to each individual wearer. They would also be challenging to get in and out of. This might require some new fabric technology that can “shrink wrap” around the wearer after being put on. But there are no plans to develop this technology, so for now we are stuck with pressurized suits.

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Sep 09 2021

Electric Vehicles by the Numbers

I recently purchased a full electric vehicle (EV) and so far I’m very satisfied with the purchase. The functionality and performance is just superior, in my opinion, to similar internal combustion engine (ICE) vehicles. The up front cost is a little higher than for a similar ICE vehicle, but that difference is coming down, especially if you consider the reduced cost of operation from reduced fuel and maintenance costs. In fact, depending on the specifics some EVs may be cheaper over the lifetime of the car vs a similar ICE vehicle. According to Consumer Reports, for example:

The Tesla Model 3 is priced lower than the gas-powered BMW 330i, and priced only about $2,000 more than an Audi A4. But the savings on operating costs for the Model 3 are about $17,000 when compared with either of the popular German gas-powered sedans.

This will only get better as battery technology improves and EV mass production increases. But the primary reason many people may purchase an EV is because they believe it is better for the environment, and they are correct. However, there is often a lot of confusion over how to properly compare EV to ICE vehicles. Let’s look just at carbon footprint – EVs do require more energy to produce, largely because of their battery, so they begin with a larger carbon footprint than a comparable ICE vehicle. Exactly how much more depends, again, on lots of variables, but mostly the size of the battery. For a 300 mile range EV the upfront carbon footprint is about twice that of an ICE.

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Sep 07 2021

The Aging ISS

The International Space Station (ISS) is getting old. Construction started on the station in 1998 and it has been continuously occupied since November 2000. Construction took 10 years, 30 missions, 15 space agencies, and 15 countries to complete. The lifespan of the modules that make up the ISS was originally set at 15 years, but this has been extended to 30 years, with the ISS commissioned through 2028. It is unclear if it will be extended beyond that.

Throughout this time the station has been repaired and upgraded, but the basic infrastructure remains. There is a certain amount of unavoidable aging that happens to hull, maintaining pressure in the challenging conditions of low Earth orbit. Without environmental control, temperature variation on the ISS would range from 250 degrees F on the sun-facing side and -250 F on the sun-opposite side. Temperature variation like this tends to fatigue material. It is therefore unclear what will happen to the ISS, and to orbiting space stations, after 2028.

The ISS cost $150 billion to build, and $3.5 billion per year to maintain. The ROI has largely been research in microgravity, including researching the ability to maintain extended stays in space. NASA plans to deorbit the ISS after 2028, and has no plans for a replacement. Its vision is to largely cede low Earth orbit to private companies. There are at least two companies with plans for their own stations, Axiom and Bigelow Aerospace. Both companies are planning modules that will attach to the ISS, and then detach and become their own free-floating stations once the ISS is decommissioned.

One of the ISS partners, Russia, has commitments to 2025. It is increasingly looking like they plan on pulling out at that time, and some speculate this is because they wish to focus on their own station. They are starting to warn about the age and condition of the ISS, especially their own modules. In July the Nauka research module’s thrusters fired accidentally, temporarily throwing the ISS out of its usual orientation. There have also been several air leaks in the Russian Zvezda service module where some of the crew sleeps. Russia is now warning that 80% of the components on their modules are past the expiration date, and that small cracks are appearing and may spread catastrophically.

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Sep 03 2021

Trust in Science May Lead to Pseudoscience

The ultimate goal of scientific skepticism is to skillfully use a process that has the maximal probability of accepting claims that are actually true and rejecting those that are false, while suspending judgment when an answer is not available. This is an open-ended process and is never complete, although some conclusions are so solid that questioning them further requires an extremely high bar of evidence. There are many components to scientific skepticism, broadly contained within scientific literacy, critical thinking skills, and media savvy. Traditional science communication focuses on scientific literacy (the so-called knowledge deficit model), but in the last few decades there has been copious research showing that this approach is not only not sufficient when dealing with many false beliefs, it may even be counterproductive.

A new study offer more evidence to support this view, highlighting the need to combine scientific literacy with critical thinking in order to combat misinformation and false claims. The study focuses on the effect of trust in science as an independent variable, and combined with the ability to critically evaluate scientific evidence. In a series of four experiments they looked at acceptance of false claims regarding either a fictional virus, or false claims about GMOs and tumors:

Depending on experimental condition, however, the claims contained references to either (a) scientific concepts and scientists who claimed to have conducted research on the virus or GMOs (scientific content), or (b) lay descriptions of the same issues from activist sources (no scientific content).

They wanted to see the effect of citing scientists and research on the acceptance of the false claims. As predicted, referring to science or scientists increased acceptance. They found that subjects who scored higher in terms of trust in science were more likely to believe false claims when scientists were cited – so trust in science made them more vulnerable to pseudoscience. For those with low trust in science, the presence or absence of scientific content had no effect on their belief in the false claims. These results replicated in the first three studies, using the fictional virus and the GMO claims.

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Sep 02 2021

Bionic Arms

The term “bionics” was coined by Jack E. Steele in August 1958. It is a portmanteau of biologic and electronic. Martin Caidin used the word in his 1972 novel, Cyborg (which is another portmanteau of cybernetic organism). But the term really became popularized in the 1970s TV show, The Six Million Dollar Man. Of course, at the time bionic limbs seemed futuristic, perhaps something we would see in a few decades. Thirty years always feels like far enough in the future that any imagined technology should be ready by then. But here we are, almost 50 years later, and we are nowhere near the technology Steve Austin was sporting. Bionics, as depicted, was more like 100 or more years premature. This is tech more appropriate to Luke Skywalker’s hand in Star Wars, rather than some secret government project in the 1970s.

We are, however, making progress, which I have been writing about periodically here. Now a team at Cleveland Clinic has produced a robot arm tested in two subjects, and they are breaking out the term “bionic” to describe their technology. They achieve their level of functionality by combining three aspects of a brain-machine interface connecting to a robotic limb – intuitive motor control, touch sensation, and kinesthetic sensation (simulating proprioception with vibration). The kinesthetic sensation allows the user to feel the robotic limb’s movements. The authors write:

Here, we show that the neurorobotic fusion of touch, grip kinesthesia, and intuitive motor control promotes levels of behavioral performance that are stratified toward able-bodied function and away from standard-of-care prosthetic users.

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Aug 31 2021

The Origins of COVID

We are approaching two years into this pandemic and we still haven’t proved the origins of the SARS-CoV-2 virus. However, this is not unusual at all, and in itself is not suspicious. It took 13 years to identify the origin of SARS, and we have never identified the origins of some Ebola outbreaks. But what do we know about the origins of SARS-CoV-2? The question has become highly political, which is unfortunate. Let’s review what the actual evidence has to say.

If we go back to the beginning of the pandemic, the early scientific investigation of the virus found that it was 96% identical to a bat coronavirus in the region. Zoonotic spillover is common, and the virus originated in a part of the world with wet markets and close contact with wild animal populations. Direct examination of the virus also did not show any telltale signs of deliberate manipulation. There has been some scientific debate on this topic, but in the end there is general agreement among scientists that there is no smoking gun of genetic manipulation. For these reasons it was concluded early that the most probable origin of COVID was from animals, either directly from bat to human or through an intermediary.

This conclusion was based on examination of the virus itself and the the reservoirs of similar viruses in the region. This was, and by many still is, considered the most likely origin. Researchers have searched for the precise animal origin, and so far have not found it, but that is not in itself unusual or suspicious.

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