Saturday, April 10, 2021

That which connects Alameda CA and Ann Arbor, MI

Lovely short article: You can take a magical tour of Alameda's fairy doors with this online map

The rise in fairy doors on Alameda began about seven years ago and is largely attributed to Fred Hogenboom and his granddaughter, Serena. The pair built about a dozen doors from scrap wood in Hogenboom's wood shop, then installed them on trees and telephone poles near Hogenboom's home on Oak Street. After that, “social media got a hold of it and from there it just blew up,” Hogenboom said, laughing.


Alameda is a whimsical little city, but it isn’t alone in its fascination with fairy doors. San Francisco has seen its own fairy door boom in recent years, and Ann Arbor, Michigan, has mysterious doors that have been around since 1993 (the doors even have their own Wikipedia page). There are notable fairy door communities everywhere from New York and Washington, D.C., to Kentucky and North Carolina.

It just so happens, I do in fact know some lovers of fairy doors, both in Alameda, and in Ann Arbor...

Thursday, April 8, 2021

Vaccine progress!

Courtesy of the City of Berkeley Health Department, today I got my first dose of the Pfizer vaccine!

I was extremely impressed with the way the mass vaccination site was run. They were very organized, they moved everybody through smoothly and accurately, and everybody who I talked to was friendly and helpful.

Including the 15 minute wait time after the shot, I was through the entire process in barely 25 minutes.

Great work by Curative, who operate the clinic, and the City of Berkeley HD!

Saturday, April 3, 2021

Giant Cargo Ship Traffic Jams Everywhere!

Forget highways, Bay Area's biggest traffic jam right now is on the bay

For the past few weeks, San Francisco Bay has been packed with huge cargo ships. There were 15 of them anchored south of the Bay Bridge at midweek. There is so much ship traffic that there is not enough room inside the bay for them all to anchor safely. Nine more big ships were waiting in the Pacific, steaming up and down 20 to 30 miles offshore between Santa Cruz and Half Moon Bay.

Everything is complicated nowadays.

Normally, a big ship like the T.Jefferson would sail up the Oakland Estuary straight from sea and not have to spend time at anchor. It would be accompanied by tugs and navigated under control of one or more pilots. The 1,200-foot-long ship would be turned 180 degrees in a basin a ways up the estuary. The turning basin has a diameter of just under 1,500 feet, so turning a 1,200-foot ship there is a delicate maneuver.

My son used to attend junior sailing classes in that turning basin, which is in the section of the estuary close to Coast Guard Island and across from the Encinal Yacht Club in Alameda.

Learning to sail those little Optimist dinghies was a wonderful memory ... I'm glad he never had to avoid the T. Jefferson!

The Known World: a very short review

Early in the new year, browsing through the scads of "best books of 2020" lists that always appear in various publications, I was struck by a note from one critic, who said something to the effect of: "yes, it's 18 years old, but The Known World is still one of the best books you could possibly read."

So I tracked it down, and spent the next two months slowly reading it, and I can confirm that that critic was entirely correct.

I'll be thinking about The Known World, and about how deeply it's affected me, for many months and years to come.

Wednesday, March 31, 2021

How important is that Amazon unionization question? Possibly, quite important.

Corey Quinn explains why: You Can’t Trust Amazon When It Feels Threatened.

This teaches us that—when it’s a big enough deal—Amazon will lie to us. And coming from the company that runs the production infrastructure for our companies, stores our data, and has been granted an outsized position of trust based upon having earned it over 15 years, this is a nightmare.

Or, possibly, it was just a Really Stupid Tweet.

Anyway, worth a read.

Friday, March 19, 2021

Vaccine confusion

Here's a snapshot of today's display on the California state Vaccines Dashboard:

I'm trying to understand what those percentages mean.

The "(78%)" for doses administered clearly means that California has administered 78% of the doses it has received -- as of today, California has received 17,661,490 doses of vaccine.

But what about the percentages "(13.7%)" and "(14.9%)" for "People partially vaccinated" and "People fully vaccinated"?

It seems like this should be interpreted as "this is the percentage of the overall population of California".

But the overall population of California as of 2020 is 39.4 million. and 13.7% of 39.4 million is 5,398,000 people, a vastly different number than 4,445,354.

If I reverse the computation, by computing ( (100 / 13.7) * 4,445,354) and also ( (100 / 14.9) * 4,825,765), I end up with 32.4 million.

Is the dashboard assuming that the California population is 32,400,000 people?

It's not like fully vaccinating nearly 5 million people is nothing, of course! But I think it's actually only about 11% of the state population, not 13.7 percent.

I must be misunderstanding something basic.

Tuesday, March 16, 2021

The Antikythera Cosmos work at UCL

A very nice video with an accompanying paper: A Model of the Cosmos in the ancient Greek Antikythera Mechanism

Using our identified period relations for all the planets, we have devised new theoretical planetary mechanisms expressing the epicyclic theories, which fit the physical evidence. For the inferior planets, previous 2-gear mechanisms are inadequate for more complex period relations because the gears would be too large. Two-stage compound trains with idler gears are necessary, leading to new 5-gear mechanisms with pin-and-slotted followers for the variable motions (Fig. 3c). For the superior planets, earlier models used direct mechanisms, directly reflecting epicyclic theories with pin-and-slotted followers. Here we propose novel 7-gear indirect mechanisms with pin-and-slot devices for variable motions (Fig. 3d), analogous to the subtle mechanism that drives the lunar anomaly. Compared to direct mechanisms, these are more economical; a better match for the evidence; and incorporate period relations exactly for higher accuracy. The crucial advantages of indirect mechanisms are expanded in Supplementary Discussion S4. Without these compact systems that can all be mounted on the same plate, it would have been impossible to fit the gearing into the available spaces. Proofs that the mechanisms in Fig. 3 correctly calculate the ancient Greek epicyclic theories are included in Supplementary Discussion S4.

I'm not sure how much of this is actually science, it strikes me more as some sort of historical-fiction-done-by-astronomy-loving-nerds.

But it's still quite interesting, and it's got some fun number theory.