Hopefully Interesting

 New sooner have I posted about the Coronavirus then a couple of new things come up. Yesterday I came across a really great paper,  Beyond Six Feet: A Guideline to Limit Indoor Airborne Transmission of COVID-19 .  It's related to a tool for figuring out risks of indoor aerosol transmission but the information in that paper was what was really interesting to me.  I'd thought that aerosols were only generated by our lungs' alveoli but apparently they can be generated by vocal cords too when you use them to speak, sing, etc.  I suppose the bit I had read earlier was making the simplifying assumption that people are silently sitting still or something.  Anyways, I'd been really interested in how much of what size of aerosol or droplet was generated by what sort of vocalization and what should this paper have but the graph I'd always wanted.     I'd previously been told that 2.5 micron aerosols are most common which looks to be  approximately true for nose breathing

I've fallen a bit out of the habit of blogging so I figured I'd do something fairly easy to start to get back in the habit.  Over the course of the pandemic I've been learning a lot about virology.  Most of this is, as far as I can tell, very basic stuff from the perspective of a virologist but it was surprising to me and might also be new to you who are reading this. Viral Load First of all, viral load is important.  I'd normally thought of people as either sick with a virus or not sick previously.  The easiest way to look at this is from the tools we use to detect viruses.  The way a PCR machine works is that you double the amount of viral RNA in a sample again and again and eventually you have enough virus to detect it by macroscopic means.  The number of times you have to double the amount of RNA before it becomes detectable is called the cyclic threshold or CT value.  For a sensitive PCR machine you can detect RNA down to a CT of 37 to 40.  And the highest viral lo

Ok, that's a somewhat provocative title but I think it's basically accurate.  During this pandemic the US in particular has had a problem with erring towards the side of better, more expensive tests when what we've really needed has been cheaper tests. An inauspicious start The US got off to a really bad start testing for Coronavirus.  Scott Gottlieb was head of the FDA until a year ago and, in contrast to many other Trump appointees, was generally acknowledged as very competent.  Back in February he put together a  Twitter thread  outlining what was happening in terms of testing which I'll summarize here.  Normally hospitals with PCR machines, which is most medium sized or larger ones, can just go ahead and develop their own tests for viruses.  However the CDC thought it would be important to have widely available testing kits which would be of a higher quality than what hospitals could do themselves.  So they asked HHS to declare that Covid-19 was a public health

Many of the worst pandemics that afflict us are from pathogens that don't normally prey on humans.  Probably the most famous pandemic in history was the Black Death.  On the steppe it lives in marmots which it has reached an equilibrium with.  But sometimes a flea transmits it to a rat.  The rat gives the disease to its other fleas and then dies.  Those fleas go to other rats and spread the disease.  When all the rats are dead the fleas find their way to humans instead.  The disease isn't quite as lethal in humans as it is in rats but it still killed a large fraction of the people who got it before the rise of antibiotics. That's pretty typical of zoonotic diseases, or diseases that spread from one species to another.  Most of the time they're just ineffective and can't survive or are mopped up easily by our automatic immune system without us noticing.  But if they succeed they're often the most dangerous diseases that can afflict us because we're not in

2019 is dead, may it rest in peace.  One thing I hope to take from the year, though, is all the things I learned in the books I finished that year.   I'm not going to review them all, there are too many, but I'll break them down into categories and bold the ones I particularly liked.  Within a category there're in chronological order, except when I mixed them up when reshuffling categories but it should be mostly right.  Some books are hard to categorize, for instance is a history of DARPA science or technology?  So it's a bit arbitrary but hopefully useful. Science The Ends of the World: Supervolcanoes, Lethal Oceans, and the Search for Past Apocalypses by Peter Brannen The 10,000 Year Explosion: How Civilization Accelerated Human Evolution by Gregory Cochran Power, Sex, Suicide: Mitochondria and the Meaning of Life  (reread) by Nick Lane The Book of Why: The New Science of Cause and Effect  by Judea Pearl and Dana Mackenzie  Lost in Math: How Beauty Leads P

It’s sad that books, TV shows, etc always overlook Callisto when talking about people having settlements on Jovian moons.  Basically nobody puts one on Io except as a weird research station which is great, because Io is objectively a terrible place to have to be unless you want to learn more about how hot sulfur behaves in high radiation environments. Europa is a common one and there are reasons for that.  We can be sure it has a liquid ocean under all that ice, which means there’s a possibility of life.  If you want a colony in a Moon’s ocean that’s an ok place to put it but we think that Ganymede and Callisto also probably have oceans too.  And they have stuff that, like, isn’t water on their surfaces if you want access to other elements for some strange reason.  If you’re not going to put a colony underwater then Europa’s surface is super radioactive and unprotected humans will tend to get a lethal dose after one day on the surface, though under a kilometer of ice you’re fine G