Transportation in the United Kingdom by Ciro Santilli 35 Updated +Created
Why it takes several days to enter inflammatory phase in COVID-19? by Ciro Santilli 35 Updated +Created
Why is it there such a clear separation of phases?
Why do people with mild symptoms go on to die? It is a great mystery.
Ciro Santilli's theory is that COVID is extremely effective at avoiding immune response. Then, in people where this is effective, things reach a point where there is so much virus, that the body notices and moves on to take a more drastic approach. This is compatible with the virus killing older people more, as they have weaker immunes systems. This is however incompatible with the fact that people don't seem to be contagious after the viral phase is over...
Why is COVID-19 so serious in some people but not in others? by Ciro Santilli 35 Updated +Created
There are a few possibilities:
Fission weapon by geometry by Ciro Santilli 35 Updated +Created
Domains by Proxy by Ciro Santilli 35 Updated +Created
Escherichia coli by Ciro Santilli 35 Updated +Created
Size: 1-2 micrometers long and about 0.25 micrometer in diameter, so: 2 * 0.5 * 0.5 * 10e-18 and thus 0.5 micrometer square.
Genome:
  • 4k genes
  • 5 Mbps
  • www.ncbi.nlm.nih.gov/genome/167
  • wget ftp://ftp.ncbi.nlm.nih.gov/genomes/all/GCF/000/005/845/GCF_000005845.2_ASM584v2/GCF_000005845.2_ASM584v2_genomic.fna.gz
  • wget -O NC_000913.3.fasta 'https://www.ncbi.nlm.nih.gov/search/api/sequence/NC_000913.3/?report=fasta'
Omics modeling: www.ncbi.nlm.nih.gov/pmc/articles/PMC5611438/ Tools for Genomic and Transcriptomic Analysis of Microbes at Single-Cell Level Zixi Chen, Lei Chen, Weiwen Zhang.
Top-level domain by Ciro Santilli 35 Updated +Created
ccTLD by Ciro Santilli 35 Updated +Created
Curl (mathematics) by Ciro Santilli 35 Updated +Created
Points in the direction in which a wind spinner spins fastest.
Ciro Santilli's 2021 cycling accident by Ciro Santilli 35 Updated +Created
Ciro had a small accident in 2021. It wasn't ultra serious, a few cuts, but could have been worse. Here's a post mortem.
Ciro was going to cycle 120 km between two locations he had never cycled before. Ciro had cycled this distance before many many times, so he thought he could do it.
What went wrong:
  • on both ends were cities, larger than those Ciro is used to
  • on the start, was a port city. You do not want to cycle in port areas, ever! Lots of trucks, narrow side-walks, bad road, danger danger!
  • on both sides, endless suburbia. This means you have to check your map every 3 seconds to know which little stree to turn, which is very hard without a way to attach your map to your bike. Ciro had his on his pocket. You lose a lot of time like that!
  • there wasn't a lot of sunlight at the time of the year. Not criticial, but still, less than ideal.
  • during the ride, part of the "well documented and safe cycle route" was closed off for repairs. It was unclear what the best alternative would be. Ciro went down a path, but it turned to be horrendous countryside, he had to pull his bike over fences
  • by then, Ciro was tired and a bit late. He had only eaten sweets all day long. They give you calories, but there's always something missing in them.
  • Ciro arrived at the very very large target city, and it was getting dark, and it was rush hour, lots of cars. This was already back on the official bike path, but even those paths are torduous in suburbia
  • also, Ciro was meant to meet his wife later, and he was in a rush, worried that she would be worried about him
  • at one point, Ciro took the wrong turn for a few hundred meters
  • he realized, and turned back
  • when coming back, now extra impatient because o the wrong turn, the place he had come from was actually one way street for a very short while until the right turn, so Ciro went against the correct direction...
  • a car came. It was relatively slow, because the road was slight uphill for the car, and a turn. The slight downhill also meant Ciro was going a bit faster than he realized
  • Ciro tried to go into the sidewalk anyways to make sure he was clear off the car (he was already). When he tried, the wheel stuck, and he flew forward, hitting a wall slightly
This was a perfect example of how many small things add up to an accident.
You have to know when you are tired and hungry and impatient. This is where huge danger lies.
Stop at a shop, eat, sit down. Darkness is not that dangerous if you have lights.
Take a train outside of large cities if needed. Crossing large cities is not something to be taken lightly. You need calm and time to do so safely.
FFmpeg filter graph by Ciro Santilli 35 Updated +Created
Filter graphs are a thing of great beauty. What an amazingly obscure domain-specific language, but which can produce striking results with very little!!!
ffplay -autoexit -nodisp -f lavfi -i '
sine=frequency=500[a];
sine=frequency=1000[b];
[a][b]amerge, atrim=end=2
'
which creates a graph:
                              +--------+
[sine=frequency=500]--->[a]-->|        |
                              | amerge |-->[atrim]-->[output]
[sine=frequency=1000]-->[b]-->|        |
                              +--------+
and plays 500 Hz on the left channel and 1000 Hz on the right channel for 2 seconds.
So we see the following syntax patterns:
  • sine, amerge and atrim are filters
  • sine=frequency=500: the first = says "araguments follow"
    • frequency=500 sets the frequency argument of the sine filter
    • for multiple arguments the syntax is to separate arguments with colons e.g. sine=frequency=500:duration=2
  • ;: separates statements
  • [a], [b]: sets the name of an edge
  • ,: creates unnamed edge between filters that have one input and one output
A list of all filters can be obtained ith:
ffmpeg -filters
and parameters for a single filter can be obtained with:
ffmpeg --help filter=sine
Related question: stackoverflow.com/questions/69251087/in-ffmpeg-command-line-how-to-show-all-filter-settings-and-their-parameters-bef
TODO dump graph to ASCII art? trac.ffmpeg.org/wiki/FilteringGuide#Visualizingfilters mentions a -dumpgraph option, but haven't managed to use it yet.
Bibliography:
FeathersJS by Ciro Santilli 35 Updated +Created
Looks interesting.
It seems to abstract the part about the client messaging the backend, which focuses on being able to easily plug in a number of Front-end web framework to manage client state.
Has the "main web API is the same as the REST API" focus, which is fundamental 2020-nowadays.
Uses Socket.IO, which allows the client Javascript to register callbacks when data is updated to achieve Socket.IO, e.g. their default chat app does:
client.service('messages').on('created', addMessage);
so that message appear immediately as they are sent.
Their standard template from feathers generate app on @feathersjs/cli@4.5.0 includes:
which looks promising! They don't have a default template for a Front-end web framework however unfortunately: docs.feathersjs.com/guides/frameworks.html#the-feathers-chat lists a few chat app versions, which is their hello world:
But it is in itself a completely boring app with a single splash page, and no database interaction, so not a good showcase. The actual showcase app is feathersjs/feathers-chat.
And there is no official example of the chat app that is immediately deployable to Heroku: FeathersJS Heroku deployment, all setups require thinking.
Global source entry point: determine on package.json as usual, defaults to src/index.js.
ARPANET by Ciro Santilli 35 Updated +Created
Bibliography:
ICMP runs on top of IP by Ciro Santilli 35 Updated +Created
This can be seen with Wireshark very clearly for example, just make a ping and disssemble it.
Taxonomic rank by Ciro Santilli 35 Updated +Created
Naming taxonomic ranks like genus, domain, etc. is a fucking waste of time, only useful before we developed molecular biology.
All that matters is the tree of clades with examples of species in each clade, and common characteristics shared by the clade.
And with molecular biology, we can build those trees incredibly well for extant species. When extinct species are involved however, things get more complicated.

Pinned article: ourbigbook/introduction-to-the-ourbigbook-project

Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
We have two killer features:
  1. topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculus
    Articles of different users are sorted by upvote within each article page. This feature is a bit like:
    • a Wikipedia where each user can have their own version of each article
    • a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
    This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
    Figure 1.
    Screenshot of the "Derivative" topic page
    . View it live at: ourbigbook.com/go/topic/derivative
  2. local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:
    This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
    Figure 5. . You can also edit articles on the Web editor without installing anything locally.
    Video 3.
    Edit locally and publish demo
    . Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.
  3. https://raw.githubusercontent.com/ourbigbook/ourbigbook-media/master/feature/x/hilbert-space-arrow.png
  4. Infinitely deep tables of contents:
    Figure 6.
    Dynamic article tree with infinitely deep table of contents
    .
    Descendant pages can also show up as toplevel e.g.: ourbigbook.com/cirosantilli/chordate-subclade
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact