Jun 17 2024

Are Animals Conscious?

This is a great scientific question because it challenges how we ask and answer scientific questions. Are animals conscious? This is a question discussed in a recent BBC article that piqued my interest. They eventually get to a question that they should have opened with – how do we specifically define “consciousness”? We can’t answer questions about an alleged phenomenon unless we know what it is. Ideally we would have an operational definition, a list of inclusion and exclusion criteria that need to be met to fit the definition.

So I am going to start with this question – how do we define consciousness? I think there are at least two different contexts here. In medicine we use the term to refer to different states in people. We know, from our own experience, that humans are conscious, and from one point of view we define consciousness as what humans experience. We assume other fully functioning humans are conscious because we are, and there is no reason to think that other beings with brains similar to our own have a fundamentally different phenomenon driving their behavior. In fact part of consciousness is a theory of mind, which is the ability to think about what other beings think and feel.

So when we talk about consciousness in humans the question revolves around the health and functioning of the brain. Someone might be unconscious, or comatose, or vegetative. We label these as “disorders of consciousness”. We might also discuss consciousness in the context of healthy altered states, such as sleeping. Here we do have very specific technical definitions, based upon neurological examination. However, even here our definition is being challenged by new technology, such as functional MRI scanning, which may shows signs of subtle consciousness in someone who does not show signs on exam.

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Jun 13 2024

Bill Gates Backs Nuclear

No one ever said that nuclear power is simple or easy. It’s a tricky and expensive technology. But it also has tremendous potential to create large amounts of reliable green low carbon energy, and many believe that we cannot ignore this potential if we are going to tackle climate change. Billionaire Bill Gates is one of those people.

In the US, since around 1990, we have generated about 19% of our electricity from nuclear power plants. Nuclear produces about 10% of the world’s power from 440 plants. The average age of a nuclear power plant in the US is 42 years – these plants were designed with a 40 year life expectancy. There have been three plants to go online this century, and the last one before that was completed in 1996 – with a 20 year gap with no new nuclear. The bottom line is that we have not been maintaining our expertise in nuclear reactors. Now we are trying to make up for lost time, but find ourselves far behind.

There are several challenges (this list is not meant to be exhaustive) – the cost of building large nuclear power plants, safety issues, sourcing the fissile material, and storing spent nuclear fuel. But there are also lots of advantages – safe reliable green power, predictable (not variable) power, and a small land footprint. Further, we can choose to build nuclear power plants on existing coal fired plant sites. This also has several advantages – the new plant can use existing connections to the grid, will minimize the economic impact to the community of shutting down a job source, and much of the site work is already done.

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Jun 11 2024

Light and Distance in an Expanding Universe

Published by under Astronomy
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Commenter Lal asks in the topic suggestions:

“Media reports that light has been travelling from that distant galaxy for 13 and a half billion years, which I assume is true, but this neither represents the original nor the current distance to that galaxy in terms of light years. I would be interested to know where we lie in the expanding universe compared to these distant galaxies.”

This is a good question, and is challenging to grasp. We need experts who have been thinking about this for decades and who actually understand what’s happening and who can explain it well. Here, I think, is an excellent discussion of this very question. I’ll give a quick summary, but for those interested, you may want to read the full article.

The basic background is that, according to modern cosmological theory, which includes the Big Bang, the universe was a singularity – one point that contained all of spacetime and all matter and energy – about 13.7 billion years ago. This point underwent rapid expansion, at first very rapid, called the inflationary period. Then it continued to rapidly expand, although at a much slower pace, although this rate of expansion has been increasing over time due to dark energy. What happens to the universe when it expands? It’s important to note first that the universe is not expanding into space – space-time itself is expanding.

Matter in the universe gets less dense and hot as the universe expands. At first matter was too hot for particles to exist. Once it cooled enough for protons and neutrons to exist, they mostly formed into hydrogen, but that was still too hot to hold onto electrons so the matter was all plasma. That eventually cooled enough for hydrogen (and some helium and a tiny bit of lithium) atoms to exist – at about 380,000 years after the Big Bang. Since then the matter in the universe has continued to cool and become less dense. However, it was also able to form stars, galaxies, heavier elements, and then lots of interesting things like people.

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Jun 10 2024

The Moon Race is On

Back in the 1960 there was a race to land people on the Moon between the US and the Soviet Union. This was very much a part of the cold war, with each country interested in showing off its technical prowess to the world with a technology closely related to that needed to deliver nuclear warheads. All the while everyone insisted this was all peaceful exploration for all mankind. But as a result we advanced our space technology with a lot of downstream effects. And of course there are many legitimate commercial uses of space, which has kept the space industries going for decades.

Now we are poised for a return to the Moon, with essentially the same tensions playing out. As of now there are five nations in the Moon club – those who have achieved soft landings on the Moon (crashing something into the Moon apparently doesn’t count) – the US, the Soviet Union, China, India, and Japan. We have yet to have a private company land something on the Moon, but we are getting close (this year Intuitive Machines launched a mission but did not make it to the lunar surface because of a fuel leak). What are the geopolitical, economic, commercial, technological, scientific and exploration factors pushing us back to the Moon? It’s complicated, but here are some factors that are commonly discussed by experts.

First, we are clearly in the midst of a new geopolitical space race, this time mainly between the US and China. And again, prestige and influence on the international stage is at stake. Strategists also talk of controlling cislunar space – essentially the space between the Earth and the Moon. This means having an infrastructure of rockets, capsules, and stations that can get to the Moon and back, either crewed or uncrewed. This includes positioning monitoring satellites to keep track of what’s happening in cislunar space, including near Earth orbit.

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Jun 07 2024

Choosing our Representatives

Published by under General
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As we are in an election year in the US, there seems to be only one thing on which there is broad agreement – this upcoming election will be consequential. So allow me to share some of my musings about the process of electing our political representatives.

Let me start by laying out what I see as the major considerations for what makes an ideal representative. This is basic stuff, but it’s worth framing the discussion. We tend to evaluate candidates on three major criteria – their overall morality and character, their experience and competence, and their ideological alignment. At least, we profess to evaluate them on these criteria, and to some extent we do. But we also use some heuristic proxies – how charismatic are they, and how good a speaker/debater are they? Sometimes we even use superficial proxies, like height – the taller candidate has won 58 percent of U.S. presidential elections between 1789 and 2008. This is obviously not a huge factor, but may tip the scales in a close election.

One question is, how do we balance the three main factors above, character, experience, and ideology? The conventional wisdom these days, which matches my experience and I think is correct, is that in the past character was not a determinative factor but a minimum bar. In other words, we generally would not necessarily vote for the person with the better character, but lack of character could be disqualifying. Many a candidate has been sunk by a “scandal” involving their moral character (ala “Monkey Business”). Although some politicians have been able to use their charisma and oratory skills to minimize the impact (think Jennifer Flowers). And again we often use dubious proxies – are they “church-going”.

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Jun 06 2024

Let’s Talk About Cement

Industry is responsible for 23% of carbon emissions, close to the amount of electricity production (25%) and transportation (28%). We talk a lot about transportation and energy, but industrial carbon is a harder nut to crack. Also, the 23% is direct carbon release from industrial processes, if you include the energy used by industry the contribution is 30%. Industry and manufacturing is increasing at a steady rate worldwide, and by some estimates we could be seeing a 90% increase in CO2 release from industry by 2050. This could wipe out any gains we make in the energy and transportation sectors.

The two largest contributors to direct industrial carbon release are steel and cement. Cement production is responsible for about 8% of CO2 emissions, about a third of industrial release. Another third is from steel. So these two industries are a ripe target for reducing carbon emissions. To put the carbon footprint into perspective, if cement production were a country, it would be the third largest emitter after the USA and China.

The world produces 4.4 billion tons of concrete each year (cement is a main ingredient in concrete). This is excepted to increase to 5.5 billion tons by 2050. Some type of cement has been used by people for about 12,000 years, with the first concrete dating to about 800 BC. The Romans perfected concrete, and built an empire out of it. Today cement and concrete are essential building materials for our modern world.

About half of the CO2 from cement production comes from the following chemical reaction – CaCO3 + heat → CaO + CO2. CaCO3 is limestone, and the CaO is what is known as clinker, a main ingredient in cement. The other half of CO2 emissions comes from the energy necessary to heat the limestone to drive the reaction. Some of that CO2 is then absorbed back by concrete, but that takes decades. There are lots of proposals for how to reduce the carbon footprint of cement and concrete, or even eliminate it. The main barrier is that any such process needs to be done on a massive scale – able to make 4.4 billion tons per year and growing.

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Jun 03 2024

Clickbait and Misinformation

Which is worse – clickbaity headlines for news articles that are factually correct, but may be playing up a sensational angle, or straight-up misinformation? It depends on what you mean by “worse”. A new study tries to address this information, with some interesting findings.

Misinformation is an increasingly important topic, one with far reaching implications for society. Our individual lives and our society is increasingly run on information. It is a critical resource, and the ability to evaluate and utilize information may be a determining factor in our quality of life. My favorite example remains Steve Jobs, because he is such a stark example. He was one of the richest people on the planet, with every physical resource at his disposal, and was a titan of an information industry. And yet he died prematurely of a potentially curable disease. He chose to delay mainstream treatment in order to pursue “natural” therapies that were ultimately worthless. We cannot know for sure what would have happened if he did not take this course, but his odds of survival would have been better.

At a societal level the most visible impact that our information ecosystems have deals with politics and public health. We are facing a rather dramatic decision regarding the next presidential election in the US, and this will ultimately be determined by how people are accessing and evaluating information. This has always been the case in a democracy, but I think most people alive today have not experienced a divergence of narrative and opinion as intense as we have today.

We also just when through the worst pandemic in a century, which brought into focus every issue dealing with misinformation. How do we deal with it in an age of social media? How do we balance the interests of making sure people get accurate health information so they can make informed choices, and freedom of speech and the value of open debate? There is no one correct answer, we just have to choose our tradeoffs.

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May 30 2024

Non-Invasive Deep Brain Stimulation

We are rapidly entering the era of neuromodulation – using electrical and magnetic fields in order to increase or decrease the activity of specific regions and circuits in the brain. Such treatments are already shown to be effective in treating some Parkinson’s symptoms, depression, OCD, migraines, and other neurological and psychiatric conditions. Computational models of brain anatomy and the connectome have dramatically increased the utility of neuromodulation. We are still on the steep part of the curve, and it will be interesting to see how far this modality goes in the next 10-20 years.

But there is one technical challenge – reaching the deep brain structures where many of the potentially targeted conditions can be found. The problem is that any electrical or magnetic field has to go through the more superficial brain tissue to get to the deeper structures. The current solution to this problem is to use invasive techniques, such as placing wires in the brain. So called “deep brain stimulation” is now done routinely, using guided stereotactic techniques, but a non-invasive way to accomplish the same goal could lead to a dramatic increase in the utility of neuromodulation.

Researchers have now published a proof of concept study looking at what they call transcranial temporal interference stimulation (tTIS).  The idea of tTIS is actually rather simple – it exploits the phenomenon of interference. Waves, regardless of what kind of waves they are, display certain core behaviors, one of which is interference. Wave are basically additive. If a peak hits a peak you get a bigger peak. If the peak of one wave coincides with the trough of another wave, the two waves will cancel each other out. This is how noise cancelling headphones work, for example.

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May 28 2024

A Greener Li-Ion Battery

It is increasingly obvious that battery technology is one of the keys to transitioning our civilization away from burning fossil fuels. Batteries facilitate the use of cheap, green, but intermittent energy sources. They also allow for the electrification of technology sectors that are currently dominated by fossil fuel, such as transportation. There is nothing easy, however, about making fundamental changes to core technologies on an accelerated timescale. The task is pushing the limits of our resources and ingenuity, and there is predictable pushback from those most affected by the change.

But there is some potentially good news – the relevant technologies are improving rapidly. In my opinion, the battery electric vehicle (BEV) is simply a superior technology to the internal combustion engine (ICE). Beyond the romantic cultural attachment to hum and roar of an engine, BEVs are more efficient, cheaper to operate, and virtually maintenance free. The fact that they are also better for the environment is almost incidental. The main challenge right now is infrastructure – installing all those charging stations.

It’s also pretty clear that the technology curve for BEVs is much steeper than for ICE vehicles (an already mature technology), so the technology advantage is likely to only increase. Core to BEV technology is the “B” part – batteries. The important stats of any BEV are largely driven by the battery – cost, range, recharge time, life expectancy. Right now the lithium-ion battery is the cutting edge technology, but there are lots of potential improvements on the horizon. There are essentially two types of possible battery technology advances – incremental advances in Li-Ion batteries themselves, or entirely new battery technology (like flow batteries). There are lots of potential new battery types being developed, but it seems that Li-Ion batteries likely have 1-2 decades of dominance left. There is also a lot of headroom in terms of perfecting the Li-Ion battery.

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May 24 2024

MOBE – A New Gene Editing System

Have you memorized yet what CRISPR stands for – clustered regularly interspaced short palindromic repeats? Well, now you can add MOBE to the list – multiplexed orthogonal base editor. Base editors are not new, they are basically enzymes that will change one base – C (cytosine), T (thymine), G (guanine), A (adenosine) – in DNA to another one, so a C to a T or a G to an A. MOBE is a guided system for making multiple desired base edits at once.

This is a complementary system to CRISPR, which targets a sequence of DNA and then uses Cas9 or a similar payload to make a double-stranded cut in the DNA. The cells natural repair system can then be leveraged to make changes during the repair process, such as inserting a new genetic sequence. In this way, and with different payloads, CRISPR can make targeted gene insertions or deletions, kill targeted cell types, or turn genes off and back on again.

MOBE cannot insert entire genes. Rather, systems like this can make single base edits. What is new about the MOBE system is that it can make multiple different types of edits at once. Some single base edits can change the nature of the resulting protein. Many single base changes in DNA are “silent” meaning that they do not alter the resulting amino acid that is coded for, because each amino acid has 3-4 similar three base pair codes. It’s also possible that a single base mutation will change the amino acid coded for, but the new amino acid is structurally similar to the previous one, so no conformational change in the protein results. But some point mutations will change one amino acid for a different one with a different effect – turning a straight line into a kink, for example. These alter the three dimensional folded structure of the protein, and therefore its function. Some point mutations may also change the code to what is called a stop codon, ending the production of the protein at that point and dramatically changing its structure.

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