Ciro Santilli @cirosantilli 40

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Eratosthenes Updated 2025-07-16

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Erhu Updated 2025-07-16

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Video 1.

Suwu herding sheep played by Song Fei (2017)

Source.

Video 2.

The 12 Most Famous Erhu Melodies in China (2021)

Source. TODO transcribe list.

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Erhu player Updated 2025-07-16

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Erik Finman Updated 2025-07-16

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www.unilad.com/technology/erik-finman-bitcoin-12-year-old-millionaire-invest-798094-20231207

In 2011, Finman made a deal with his parents that he would not pursue a college degree as he wanted to make his fortune outside of traditional education.
After receiving $1,245 from his grandmother that year, Finman invested into Bitcoin (BTC) - which was then trading at around $12 - and this gave him about 103 BTC.

Shame that he seems to be a American exceptionalism idiot. Perhaps it was inevitable given his circonstances. After a small market crash: x.com/erikfinman/status/1820457023013626322.

Opportunities like this come across only once every few years.
This ain’t financial advice…
But if you got the cash.
Never bet against America

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Ernest Hemingway Updated 2025-07-16

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Ernest Lawrence Updated 2025-07-16

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1932 Nobel Prize in Physics for cyclotron.

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Erotica Updated 2025-07-16

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Escherichia coli Updated 2025-07-16

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www.cell.com/cell/fulltext/S0092-8674(15)00568-1 2015. Using Genome-scale Models to Predict Biological Capabilities. Edward J. O'Brien, Jonathan M. Monk, Bernhard O. Palsson.
www.quora.com/What-are-some-good-books-on-Escherichia-Coli-E-Coli

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.

Reference strain: E. Coli K-12 MG1655.

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'

Synthesis project: www.sciencemag.org/news/2016/08/biologists-are-close-reinventing-genetic-code-life

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.

Bibliography:

ecoliwiki.org/colipedia/index.php/Welcome_to_EcoliWiki

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Escola da Ponte Updated 2026-01-30

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www.escoladaponte.pt/

Video 1.

Aprender em Comunidade by Prof. José Pacheco

. Source. In Portuguese. Title translation: "Learn in community".

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Essential metabolism for a minimal cell (2019) Updated 2025-07-16

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elifesciences.org/articles/36842

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Ethernet Updated 2025-07-16

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Ethnic minorities in China Updated 2025-07-16

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As of 2020 (TODO starting when) the Chinese government officially recognizes 55 minorities.

These minorities actually had different legal statuses, e.g. they were exempt from the One Child Policy.

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Euclidean metric signature matrix Updated 2025-07-16

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The identity matrix.

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Euclid's formula Updated 2025-07-16

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Euclid's postulates Updated 2025-07-16

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Postulates are what we now call axioms.

There are 5: en.wikipedia.org/w/index.php?title=Euclidean_geometry&oldid=1036511366#Axioms, the parallel postulate being the most controversial/interesting.

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Eugenics Updated 2025-07-16

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Euler-Lagrange equation Updated 2025-07-16

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Let's start with the one dimensional case. Let the

q : R \to R

and a Functional

I

defined by a function of three variables

F : R^{3} \to R

I (q) = \int_{t_{0}}^{t} F (t, q (t), \overset{q}{˙} (t)) d t

(1)

Then, the Euler-Lagrange equation gives the maxima and minima of the that type of functional. Note that this type of functional is just one very specific type of functional amongst all possible functionals that one might come up with. However, it turns out to be enough to do most of physics, so we are happy with with it.

Given

F

, the Euler-Lagrange equations are a system of ordinary differential equations constructed from that

F

such that the solutions to that system are the maxima/minima.

In the one dimensional case, the system has a single ordinary differential equation:

\frac{\partial F ( t , q ( t ) , q ˙ ( t ))}{\partial q} - \frac{d}{d t} \frac{\partial F ( t , q ( t ) , q ˙ ( t ))}{\partial q ˙} = 0

(2)

\frac{\partial F}{\partial q}

and

\frac{\partial F}{\partial q ˙}

we simply mean "the partial derivative of

F

with respect to its second and third arguments". The notation is a bit confusing at first, but that's all it means.

Therefore, that expression ends up being at most a second order ordinary differential equation where

q

is the unknown, since:

the term $\frac{\partial F ( t , q ( t ) , q ˙ ( t ))}{\partial q}$ is a function of $t, q (t), \overset{q}{˙} (t)$
the term $\frac{\partial F ( t , q ( t ) , q ˙ ( t ))}{\partial q ˙}$ is a function of $t, q (t), \overset{q}{˙} (t)$ . And so it's derivative with respect to time will contain only up to $\overset{q}{¨}$