Archive for July, 2024

Jul 11 2024

The Neolithic Revolution

Published by under Culture and Society

What was the greatest invention of human civilization? Arguably it was agriculture, which allowed for civilization itself. Prior to agriculture humans were some combination of hunters, gatherers, scavengers, and fishers. We lived off the land, which was a full-time job. Many communities had to be nomadic, to follow prey and follow the seasons. There were some permanently occupied sites, if they were in proximity to an adequate food source. Food was the ultimate limiting factor on human populations and ingenuity.

Agriculture was therefore a transformative invention, allowing people to stay in one place and develop infrastructure. It also freed up some members of the group to do things other than focus on acquiring food. It made civilization possible. How far back does agriculture go?

The consensus is that agriculture began in earnest about 12,000 years ago, in the fertile crescent that is now Iran, Iraq, Turkey and surrounding regions. Evidence for this includes the remnants of domesticated plants, and also evidence of farming and food processing. In addition there is evidence of domesticated animals, which would have been a source of labor and also an additional food source. There were also some downsides to this shift in lifestyle – relying on a narrow range of plants reduced food diversity and therefore overall nutritional quality. Living with domesticated animals, and in larger populations, also saw the rise of communicable diseases. The latter still plagues humanity. However, successful societies all figured out eventually how to farm a combination of plants that would provide adequate nutrition. You may have noticed that most cultures’ staple foods include some combination of a grain plus a legume – corn and beans, rice and lentils, for example.

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Jul 09 2024

Trust in New Technology

In an optimally rational person, what should govern their perception of risk? Of course, people are generally not “optimally rational”. It’s therefore an interesting thought experiment – what would be optimal, and how does that differ from how people actually assess risk? Risk is partly a matter of probability, and therefore largely comes down to simple math – what percentage of people who engage in X suffer negative consequence Y? To accurately assess risk, you therefore need information. But that is not how people generally operate.

In a recent study assessment of the risk of autonomous vehicles was evaluated in 323 US adults. This is a small study, and all the usual caveats apply in terms of how questions were asked. But if we take the results at face value, they are interesting but not surprising. First, information itself did not have a significant impact on risk perception. What did have a significant impact was trust, or more specifically, trust had a significant impact on the knowledge and risk perception relationship.

What I think this means is that knowledge alone does not influence risk perception, unless it was also coupled with trust. This actually makes sense, and is rational. You have to trust the information you are getting in order to confidently use it to modify your perception of risk. However – trust is a squirrely thing. People tend not to trust things that are new and unfamiliar. I would consider this semi-rational. It is reasonable to be cautious about something that is unfamiliar, but this can quickly turn into a negative bias that is not rational. This, of course, goes beyond autonomous vehicles to many new technologies, like GMOs and AI.

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Jul 08 2024

Some Thoughts on Aging

Published by under Neuroscience

If either of the two presumptive nominees for the major political parties in the US are elected in November they will be the oldest person ever to be inaugerated as president. What implications does this have? As a neurologist who sees patients every workday of various ages, evaluates them, and explicitly investigates the effects of aging on their function, I have some thoughts.

The first thing to realize is that aging affects different people differently. Especially once people get north of 40 you start to see significant and growing divergence in how well people age, in terms of their health and various aspects of functioning. I have seen many patients in their 90s who are completely sharp and fully functional or have just specific issues to deal with, but are overall healthy. I have also seen patients in their 50s who are wrecked and suffering from various aspects of declining health.

This divergence is partly due to the luck of genetics, and partly due to lifestyle. Some people have a chronic illness that dramatically affects their aging. Others may have suffered an injury with long term effects that get more challenging with age. While others have engaged in one or more poor lifestyle choices and have paid a heavy toll. Chronic alcohol use disorder, for example, can be devastating, adding years or decades to one’s apparent age. Smoking also takes its toll.

For these reasons, what we can say about a person based upon just a number is actually quite limited. We can make statistical comments, but that’s all. Even there, we can only describe what is typical, but there are exceptions. There are, for example, so-called “super agers” who do not develop the typical brain changes that most people do with age.

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Jul 02 2024

DNA Nanorobot Kill Switch for Cancer

How’s that for a provocative title? But it is technically accurate. The title of the paper in question is: “A DNA robotic switch with regulated autonomous display of cytotoxic ligand nanopatterns.” The study is a proof of concept in an animal model, so we are still years away from a human treatment (if all goes well), but the tech is cool.

First we start with what is called “DNA origami”. These are sequences of DNA that fold up into specific shapes. In this case the DNA origami is used to create a nanoscale “robot” which is used as a delivery mechanism for the kill switch. The skill switch is quite literal – a “death receptor” (DR) which is a ligand of 6 amino acids. These exist on all healthy cells, but when sufficiently clustered on the surface of a cell, DRs trigger apoptosis, which is programmed cell death – a death switch.

The DNA origami robot has six such ligands arranged in a hexagonal pattern on the interior of its structure. The DNA, in fact, creates this structure with precise distance and arrangement to effectively trigger apoptosis.  When it opens up it reveals these ligands and can attach them to a cell surface, triggering apoptosis. The researchers have managed to create a DNA robot that remains closed in normal body pH, but also will open up in an acidic environment.

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Jul 01 2024

BBC Gets Into UFOs

Published by under UFO's / Aliens

Paranormal phenomena tend to wax and wane in the public interest. Typically a generation will become fascinated with a topic, but eventually the novelty will wear thin and interest will fade. But the flame will be kept alive by the hardcore believers. Wait long enough, and interest will come around again. We are seeing this today with UFOs (Unidentified Flying Objects, now technically terms UAPs or Unidentified Anomalous Phenomena).

Not surprisingly the BBC wants to get in on this UFO action, and they are doing that with their Paranormal series, which they are promoting on their news outlet. They clearly are trying to remain respectable, and not completely abandon their journalistic integrity, but they predictably fall for all the usual fallacies that skeptics have explained many times over decades.

They focus on an incident in Wales in 1977 at the Broad Haven elementary school. This is often referred to as the Roswell of Wales. There were reports that day of something strange going on, including a silver humanoid walking around town, and possible UFO sightings. Some of the students thought they saw something in a field near the school’s playground, and many students then went out to take a look. What UFO believers point to as “compelling” evidence that they saw an actual space craft is that the students, under questioning by the school staff, all drew similar images of what they saw – a pretty typical flying saucer. The BBC captions a picture of some of these drawings: “The children reportedly drew near identical images of the UFO, which captured widespread media attention.”

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