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Western spotted skunk

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Yellow-throated Marten


Archive for March, 2023

Downloading a video from an ebay listing

Wednesday, March 8th, 2023

Using Firefox, go to the item page, open the Firefox Web Developer Tools (Menu -> More tools -> Web Developer Tools). Click on the Network tab in the Tools section, then on the web page click on the video and play it.

In the Network tab, requests for audio_128kb-0.m4s to audio_128kb-16.m4s appeared, and video_720p-0.m4s to video_720p-16.m4s. I copied the URL for the video and audio requests (all the same but with a different -0 to -16 segment), and used wget to download the files. Each was 1-2 MB:


After 32 wget commands, the entire video was present. I downloaded segments from 0 up until after number 16, I got a ‘not found’ message letting me know I had the last segment.

Then I concatenated the pieces together:

cat video_720p-0.m4s >> video_720p.m4s
cat video_720p-1.m4s >> video_720p.m4s
cat video_720p-16.m4s >> video_720p.m4s

And the same for the audio segments. I put the cat commands into a batch file “cat.txt” and ran them using “bash cat.txt”.
Then ffmpeg was used to combine them and convert to mp4 format:

ffmpeg -i video_720p.m4s -i audio_128kb.m4s -c copy ebay_720p.mp4

Links for March 2023

Monday, March 6th, 2023

The Bluestocking, vol 259: Dahl and Fleming

Two Stories About Tacit Knowledge To build a nuke or (can) not build a nuke by Rohit.Krishnan

Book: The Gutenberg Parenthesis The Age of Print and Its Lessons for the Age of the Internet by Jeff Jarvis (2023)
“The Gutenberg Parenthesis traces the epoch of print from its fateful beginnings to our digital present – and draws out lessons for the age to come.”

Book: Glass Art From the Kiln by Rene Culler (2010)

Marx generator This circuit generates a high-voltage pulse by charging a number of capacitors in parallel with DC, then suddenly connecting them in series.

Perimeter of an Ellipse. Estimate or infinite series.

2014-2015 Flint water lead

Monday, March 6th, 2023

This article by Kevin Drum argues that the Flint water lead poisoning episode was not that bad, there was little lasting damage, and the biggest issue today is people hyping the issue and scaring kids (link).

I have to disagree that “…little damage done. Lead levels never got all that high”. True, the attention the problem received led to a quick response that soon fixed the water, and the lead levels in children’s blood began to decline.

But when the lead issue was discovered, “Resident Zero”’s water had lead levels of 217–13,200 μg/L, 14X – 900X alarming levels (!

In the initial study, in 7 of the 9 Flint wards, > 20% of households had water lead levels > 15 ppb, the action level. In the worst wards, child blood lead levels were elevated in 11%, 9%, and 6% of children ( In a quick search, I don’t see how high blood lead levels rose in these kids.

There were 17 months between the water switch and the start of corrective measures. The water lead issue was first identified in Feb 2015, and testing over the spring and summer raised greater and greater alarm as it became clear this was a widespread water issue, and then in Oct 2015 corrective measures were taken.

Several thousand children <6 years old (of 9,000 in Flint) had significantly elevated blood lead levels for more than a year due to this poisoning.

COVID-19 origins, again

Saturday, March 4th, 2023

With an announcement by the DOE, that they sorta think COVID-19 leaked from a lab, the discussion is back on. But there is no new evidence, just a mention of ‘intel’.

I am not an intelligence professional, but I have a few related
questions. US intel on this could come from phone intercepts, emails
collected in real time or hacked out more recently, or from chatting
up Chinese virologists at conferences, etc., but this will give the US
at best a more limited view than the Chinese govt has. No doubt there
were calls, emails, reports issued, panic and alarm as China became
aware of the outbreak and tried to contain it. But how likely is it
that the Chinese govt or scientific officials knew the origins of
COVID-19 early on, or worked it out later on? If Chinese officials
don’t know, an effective intelligence operation can’t extract an

How could China know? If one or more people at the Wuhan Institute of
Virology came down with COVID-19, passed it on to family and
acquaintances, and then COVID-19 spread more widely, they could track
these connections. Classic gumshoe epidemiology. But that did not

Chinese doctors only became aware of a new disease in Dec 2019, health
officials jumped in by the end of Dec, and samples were collected from
Jan 2019 – March 2020 in the Wuhan market. These samples and those
from early cases in the region have all been sequenced, published, and
shared. This was close to the origin of the pandemic, and it is
unlikely China has any better information on what happened than the
rest of us have. COVID-19 passing into humans much earlier and only
becoming pandemic in 2019 is ruled out by the analysis of COVID-19

The best guess at the origin of COVID-19 remains a couple of papers looking at the evidence, the epidemiological evidence of when and where early cases arose, and how it was transmitted, and the genomic evidence from sequencing of COVID-19 in early patients, and comparing these to each other to make a tree of early -> later virus genomes, and to see how the early viral genomes in human patients differ from wild relatives and samples found in the Wuhan live animal market. This sort of analysis can also provide estimates of time–how long the virus has been circulating in human hosts. (ref1, ref2, ref3).