Type of laser by Ciro Santilli 37 Updated +Created
Lasers vs other light sources by Ciro Santilli 37 Updated +Created
The key advantages of lasers over other light sources are:
One cool thing about lasers is that they rely on one specific atomic energy level transition to produce light. This is why they are able to to be so monchromatic. Compare this to:
As such, lasers manage to largely overcome "temperature distribution-like" effects that create wider wave spectrum
Video 1.
Crazy difference between 5W laser and 5W LED by Brainiac75
. Source. Baseic but good. Uses a laser photometer.
Laser spectrum by Ciro Santilli 37 Updated +Created
Video 1.
Spectrum of laser light by Shaoul Ezekiel
. Source. 2008, MIT.
Twisted pair by Ciro Santilli 37 Updated +Created
Education of André-Marie Ampère by Ciro Santilli 37 Updated +Created
en.wikipedia.org/w/index.php?title=Andr%C3%A9-Marie_Amp%C3%A8re&oldid=1211946256:
Jean-Jacques Ampère, a successful merchant, was an admirer of the philosophy of Jean-Jacques Rousseau, whose theories of education (as outlined in his treatise Émile) were the basis of Ampère's education. Rousseau believed that young boys should avoid formal schooling and pursue instead a "direct education from nature." Ampère's father actualized this ideal by allowing his son to educate himself within the walls of his well-stocked library.
TODO find the source for this.
Electrical cable by Ciro Santilli 37 Updated +Created
One more more electrical wires surrounded by an insulator.
Oliver Heaviside by Ciro Santilli 37 Updated +Created
He participated in the development of the electrical telegraph, and he did some good modeling work that improved the foundations of the field, notably creating the telegrapher's equations.
He was one of those idealists who just want to do some cool work even if they have to starve for it, people had to get a state pension for him for his contributions. Nice guy. en.wikipedia.org/w/index.php?title=Oliver_Heaviside&oldid=1230097796#Later_years_and_views:
In 1896, FitzGerald and John Perry obtained a civil list pension of £120 per year for Heaviside, who was now living in Devon, and persuaded him to accept it, after he had rejected other charitable offers from the Royal Society.
He also never married: www.nndb.com/people/627/000204015/
Figure 1.
Oliver Heaviside c. 1900
. Source.
We intersect 2013 DNS Census virtual host cleanup with 2013 DNS census MX records and that leaves 460k hits. We did lose a third on the the MX records as of 260 hits since secureserver.net is only used in 1/3 of sites, but we also concentrate 9x, so it may be worth it.
Then we Wayback Machine CDX scanning. it takes about 5 days, but it is manageale.
We did a full Wayback Machine CDX scanning for JAR, SWF and cgi-bin in those, but only found a single new hit:
Integer factorization algorithms better than Shor's algorithm by Ciro Santilli 37 Updated +Created
A group of Chinese researchers have just published a paper claiming that they can—although they have not yet done so—break 2048-bit RSA. This is something to take seriously. It might not be correct, but it’s not obviously wrong.
We have long known from Shor’s algorithm that factoring with a quantum computer is easy. But it takes a big quantum computer, on the orders of millions of qbits, to factor anything resembling the key sizes we use today. What the researchers have done is combine classical lattice reduction factoring techniques with a quantum approximate optimization algorithm. This means that they only need a quantum computer with 372 qbits, which is well within what’s possible today. (The IBM Osprey is a 433-qbit quantum computer, for example. Others are on their way as well.)
python/sphinx by Ciro Santilli 37 Updated +Created
To run each example and see the output run:
./build.sh
xdg-open out/index.html
python/sphinx/hello by Ciro Santilli 37 Updated +Created
Minimal example. Gives a hint at how boilerplate heavy Sphinx can be!
python/sphinx/class by Ciro Santilli 37 Updated +Created
Basic class example.
SQL histogram by Ciro Santilli 37 Updated +Created
Let's try it on SQLite 3.40.1, Ubuntu 23.04. Data setup:
sqlite3 tmp.sqlite 'create table t(x integer)'
sqlite3 tmp.sqlite <<EOF
insert into t values (
  0,
  2,
  2,
  3,

  5,
  6,
  6,
  8,
  9,

  17,
)
EOF
sqlite3 tmp.sqlite 'create index tx on t(x)'
For a bin size of 5 ignoring empty ranges we can:
sqlite3 tmp.sqlite <<EOF
select floor(x/5)*5 as x,
       count(*) as cnt
from t
group by 1
order by 1
EOF
which produces the desired:
0|4
5|5
15|1
And to consider empty ranges we can use SQL genenerate_series + as per stackoverflow.com/questions/72367652/populating-empty-bins-in-a-histogram-generated-using-sql:
sqlite3 tmp.sqlite <<EOF
select x, sum(cnt) from (
  select floor(x/5)*5 as x,
         count(*) as cnt
    from t
    group by 1
  union
  select *, 0 as cnt from generate_series(0, 15, 5)
)
group by x
EOF
which outputs the desired:
0|4
5|5
10|0
15|1
SQL spatial index by Ciro Santilli 37 Updated +Created
SQL subquery by Ciro Santilli 37 Updated +Created
Window function (SQL) by Ciro Santilli 37 Updated +Created

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