@weekend_editor@mathstodon.xyz
@weekend_editor@mathstodon.xyz avatar

weekend_editor

@weekend_editor@mathstodon.xyz

Retired physicist, after a career in machine learning & stats mostly for cancer drug discovery. Now blogging about stats in the news.

Avatar: convergence basins in the complex plane of Newton's algorithm searching for the cube roots of unity. (After a NYT column by https://mathstodon.xyz/@stevenstrogatz, long ago.)

Header: Quote from GK Chesterton, London Daily News, 1905-Aug-16 on epistemic humility and the ability to say "I am wrong" as the foundation of idealism.

#statistics #physics #r

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johncarlosbaez, to random
@johncarlosbaez@mathstodon.xyz avatar

Imagine the gravitational equivalent of a hydrogen atom. This would be two particles bound by their gravitational attraction, described by a quantum-mechanical wave function.

Alas, nobody has ever seen such a thing. But why not?

The particles couldn't be charged, since then the electromagnetic force would swamp the gravitational force. But suppose we used neutrons! We can work out the Bohr radius of two gravitationally bound neutrons, ignoring the nuclear force between them, and...

...well, I'll leave it as a puzzle: is it very large, or very small?

If it's very small, then of course the nuclear force would swamp the gravitational force, and that would explain why we don't see "gravitational atoms" made of 2 neutrons.

But if it's very large, then on average the neutrons would be quite far apart, so the nuclear force between them might really be negligible: that force goes to zero much faster than the inverse square law obeyed by gravity. So then things get more interesting!

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@johncarlosbaez

Wheeler proposed this in 1955, albeit with EM or gravitational waves that were gravitationally bound.

I found out about it while, as a grad student avoiding thesis work, I took a stroll in a basement library at MIT. There's some WEIRD stuff in the literature!

JA Wheeler, "Geons", Phys Rev 97:2, 511–536. DOI: 10.1103/PhysRev.97.511.

https://en.wikipedia.org/wiki/Geon_(physics)

johncarlosbaez, (edited ) to random
@johncarlosbaez@mathstodon.xyz avatar

You may have seen this Jedi math trick: take something that makes sense with real numbers and try it with complex numbers. Weird yet useful things happen.

For example it turns out that imaginary time is 1/temperature. Hawking used this to compute the temperature of black holes.

An easier example is that the exponential function applied to an imaginary number gives you the trig functions sine and cosine.

Indeed, if ω is any complex number, exp(iωt) is a function of time that oscillates at a frequency equal to the real part of ω, and decays exponentially at a rate equal to the imaginary part of ω. So we can think of ω as a complex frequency! Its real part is an ordinary frequency, while its imaginary part is a decay rate.

Thus, in music it makes sense to consider tuning systems where the frequency ratios are complex. I haven't yet found anything interesting to do with this thought. But it makes sense to have notes that oscillate but also decay.

Here's a dumb idea. Nobody knows Bach's original well-tempered scale. In 1977, Herbert Anton Kellner had a wacky suggestion: the beats in the major third (which is close to a frequency ratio of 5/4, but not quite) should have the same frequency as those of the perfect fifth (which is close to 3/2, but not quite).

This led him - the derivation is too long to fit in the margin of this post - to the 'Bach equation':

F⁴ + 2F - 8 = 0

where F is the frequency ratio of the perfect fifth. He got a solution

F ≈ 1.495953506

for the perfect fifth. But it also has a negative solution, and two complex solutions that aren't real. Do these mean anything?

Maybe you can come up with a better idea about complex tuning systems....

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@johncarlosbaez

> But it also has a negative solution, and two complex solutions that aren't real. Do these mean anything?

Usually when I get a positive and negative root in frequency space:

They're the same magnitude and I'm being reminded that there's a sine and cosine solution from the wave equation hiding in there somewhere.

Basically exp(+iωt) and exp(-iωt).

The imaginary roots, if this extends to them, may be an exponential growth and decay?

johncarlosbaez, (edited ) to random
@johncarlosbaez@mathstodon.xyz avatar

For my Christmas present this year I hope Santa fixes this website - or shuts it down. This symbol does not mean "approximately equal to" - that's

≈

This symbol means "isomorphic to", or "congruent to". I cannot stand another year with this misinformation ruining my Google searches.

https://www.fileformat.info/info/unicode/char/266f/index.htm

𝐍𝐚𝐫𝐫𝐚𝐭𝐨𝐫: 𝐁𝐮𝐭 𝐭𝐡𝐞 𝐩𝐫𝐨𝐛𝐥𝐞𝐦 𝐠𝐨𝐞𝐬 𝐝𝐞𝐞𝐩𝐞𝐫 𝐭𝐡𝐚𝐧 𝐁𝐚𝐞𝐳 𝐭𝐡𝐢𝐧𝐤𝐬. 𝐑𝐞𝐚𝐝 𝐨𝐧!

weekend_editor, (edited )
@weekend_editor@mathstodon.xyz avatar

@johncarlosbaez

"~" also means "is distributed as" with a random variable on the LHS and a distribution family on the RHS.

Unicode explanations are usually written by character set experts, whose grasp of mathematics is mostly that they think it's a pain in their rear.

(But, confession: I also in the past used "~" as "approximately equal". Because I often had to type it into an email where non-ASCII was no end of pain to type, and absolutely no guarantee of what would come out on the recipient's end.)

johncarlosbaez, (edited ) to random
@johncarlosbaez@mathstodon.xyz avatar

Yes, this guy is playing Scottish folk music in a pub on Christmas eve... on a bouzouki! This instrument jumped from Greece to Ireland in the 60s, but now it's used in Scottish folk music too.

We're having a great evening. I hope you are too.

For more on the Irish bouzouki, try this:

https://en.m.wikipedia.org/wiki/Irish_bouzouki

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@johncarlosbaez

I remember hearing Andy M Stewart of Silly Wizard giving a crazy "explanation" of the bouzouki in a Scottish group, back in the 80s in Boston.

I couldn't decide if they were a stand-up comedy group or a music group, and didn't mind being confused by people with multiple skills.

lednabwm, to random

Hmmm....🤔 🤣😂🤣😂🤣

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@jeffowski @lednabwm

You tread quite close to reality.

Brazilian Catholic archbishop Hélder Pessoa Câmara, a proponent of liberation theology, said:

"When I give food to the poor, they call me a saint. When I ask why they are poor, they call me a communist."

He described himself as a socialist.

https://en.wikipedia.org/wiki/H%C3%A9lder_C%C3%A2mara#:~:text=C%C3%A2mara%20preached%20for%20a%20church,they%20call%20me%20a%20communist.%22

siderea, (edited ) to random

There are two problems that are coming for Mastodon of which apparently an awful lot of people are unaware. These problems are coming for Mastodon not because of anything specific to Mastodon: they come to all growing social media platforms. But for some reason most people haven't noticed them, per se.

The first problem is that scale has social effects. Most technical people know that scale has technological effects. Same thing's true on the social side, too.

🧵

CC: @Gargron

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@siderea

You will probably like David Chapman's essay, "Geeks, MOPs, and Sociopaths".

It's about how communities always get invaded by those who wish to USE the community instead of BE the community.

https://meaningness.com/geeks-mops-sociopaths

pkw, to random
@pkw@mastodon.sdf.org avatar

(musing)
What's the function to map over a hash-table?

hashmap ... nope
hash-map ... nope
map-hash ... nope
maphash ... 😋

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@sigue @lispm

People like to dump on "design by committee", usually with good reason.

But given the quality of the result (CommonLISP) and the intelligence & experience of the X3J13 members, this is clearly a positive exception.

Skepticat, to random
@Skepticat@mstdn.social avatar

If you hurt yourself after turning 50, you just stay hurt.

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@Skepticat

After 65, you don't even have to hurt yourself first.

You just hurt by default.

gutenberg_org, to philosophy
@gutenberg_org@mastodon.social avatar

"Philosophy is perfectly right in saying that life must be understood backward. But then one forgets the other clause—that it must be lived forward."

Danish philosopher Søren Kierkegaard died in 1855. Much of his philosophical work deals with the issues of how one lives as a "single individual," giving priority to concrete human reality over abstract thinking and highlighting the importance of personal choice and commitment.

Søren Kierkegaard at PG:
https://www.gutenberg.org/ebooks/author/46682

Title page of the first edition of Søren Kierkegaard's Fear and Trembling (1843).

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@gutenberg_org

The Danish original (Journalen JJ:167 (1843)) is a bit longer, explaining that in medias res is a terrible starting place to understand one's life:

Original Danish: “Det er ganske sandt, hvad Philosophien siger, at Livet maa forstaaes baglaends. Men derover glemmer man den anden Saetning, at det maa leves forlaends. Hvilken Saetning, jo meer den gjennemtaenkes, netop ender med, at Livet i Timeligheden aldrig ret bliver forstaaeligt, netop fordi jeg intet Øieblik kan faae fuldelig Ro til at indtage Stillingen: baglaends.”

English: “It is really true what philosophy tells us, that life must be understood backwards. But with this, one forgets the second proposition, that it must be lived forwards. A proposition which, the more it is subjected to careful thought, the more it ends up concluding precisely that life at any given moment cannot really ever be fully understood; exactly because there is no single moment where time stops completely in order for me to take position [to do this]: going backwards.”

https://www.someweekendreading.blog/quotes/#:~:text=%E2%80%9CLife%20can%20only,be%20lived%20forwards.)

rml, to Lisp
@rml@functional.cafe avatar


https://www.ebay.com/itm/325709617062?hash=item4bd5ce57a6:g:pWUAAOSwNIJkmhFE&amdata=enc%3AAQAIAAAA4OPv%2BaG23GBv6TS3E8I%2FruyybIuR2CI%2FRiJ%2FjXWOoOkFeqwIZh2h2JZXxyuvmzdSNEJDMDEHAj0Vfqz47PvFreKLpLWGvkxYZe5Sw9NsO%2BKiOysDQo1D8iAMk%2B9lEYRdsTY0ItcQYh7jJcP8C54xOaCGfrfy3A8wPbyWPV%2FZwl8J0lQeLMRsBIvLhNlC29oVM0%2BDgg70%2FKAqTWvbzurLgxd%2FCoEAxhdHKiEi8a%2FDpDRInjxdr8j%2BWPRlbyRoyKWPdwKaKIehYUzn5xZLUm2%2BpM2Phn%2Buffit465sMPbt4b1p%7Ctkp%3ABk9SR4acuq73Yg

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@rml

wiping away a tear of nostalgia

We had some great ads.

But...

We also had some TERRIBLE ads, like:

"The future of computing is here. Is your company ready to step in it?"

After explaining the US rural slang meaning of "step in it" (see below), R&D proposed that all future Marketing slogans be vetted for double entendre by a panel of 12 year old boys.

DIdn't work. Worth a shot.

https://www.urbandictionary.com/define.php?term=stepped%20in%20it

w7voa, to random
@w7voa@journa.host avatar

DoJ files files documents in court cases stating the right to interstate travel is protected by the US Constitution when used to access legal abortion procedures. https://www.justice.gov/opa/pr/justice-department-files-statement-interest-case-right-travel-access-legal-abortions

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@w7voa

Bit late, unfortunately: there's already been a pretty outrageous arrest in Idaho for driving to Oregon for an abortion.

Complicating factors: the driver took her son and his underage girlfriend on the abortion trip, at their request. But since she was underage & didn't want to tell her parents, they ALSO got slapped with kidnapping & statutory rape charges.

https://jessica.substack.com/p/idahos-first-abortion-trafficking

siderea, to random

Huh. Somebody is trying to hijack my Zoom account associated with the email address I set up to use exclusively with my graduate school.

Which doesn't exist.

The Zoom account I mean. Both the university and the email address exist.

I don't have a Zoom account associated with that email address.

I'm really sure about that. Because I don't have any Zoom accounts whatsoever.

I wonder to whom I should report this. While this isn't a hugely secret email address, in that I shared it with a lot of my fellow students as well as the university, it's not one at which I ever get any spam, so it is pretty secret.

Since they, whoever they are, haven't managed to hijack it, they're now trying to create a Zoom account with my secret email address for school stuff, which is at my personal domain.

This is not working out very well for them, because the confirmation email went to me.

Not really looking forward to the idea of explaining the problem to the school.

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@siderea

> ...it turned out to be some chick in the psych school...

"Chick"? Heh.

Haven't heard THAT one in a good long while.

Style points for the use of vintage slang as a sarcasm amplifier.

lauren, to random
@lauren@mastodon.laurenweinstein.org avatar

If a mistake by a single employee in a large organization can put your network and data at risk, your systems are deficient.

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@lauren

Or, as we used to say at the beginning of the COVID-19 pandemic:

If your "safety protocol" is unstable with respect to just a few noncompliant idiots, then it was neither safe nor a protocol.

See several universities with isolation and making protocols in the presence of fraternities and alcohol.

Real safety protocols, like in hospitals, have 2 properties:

(1) They're robust against single mistakes, and will at least detect double mistakes. (Triple mistakes can kill somebody.)

(2) They're largely error-correcting due to peer review, i.e., you can screw up but your colleagues will save you. (Good review is an asset, not meddlesome supervisors.)

isomeme, to accessibility
@isomeme@mastodon.sdf.org avatar

Sometimes I can't help but wonder whether some large fraction of product designers actively hate people with low vision. For example, I just had to take a photo and use zoom and image enhancement to determine that this Keurig pod is decaffeinated.

If I were Empress of Earth, I would allow only vision-impaired people to work as product or UX designers.

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@isomeme

I have a friend of many years who is a graphic designer / product designer. (He prefers just "designer", as though there were no other kind.)

He has also gradually lost much of his high-quality vision over the years.

When he designs something, he always thinks: "Will I be able to read/use this in another decade?"

siderea, to random

What's the possessive of Alzheimer's?

I just tried to formulate the following sentence: "I recall reading about some research that seemed to find that problems in sleep architecture proceeded onset of Alzheimer's (other) symptoms by up to two decades".

This is driving me slightly nuts. I mean, technically, if English were sensible and consistent, in the above sentence it should be "Alzheimer's's".

weekend_editor, (edited )
@weekend_editor@mathstodon.xyz avatar

@siderea

Also, you probably meant to say "preceded" instead of "proceeded". :-)

I love the idea of submitting a pull request to the maintainers of the English language.

However, I suspect the implementation is, and thus all patches must be, in INTERCAL.

Isn't there an XKCD in which the puncline is somebody praying, "Dear G-d, I would like to submit a bug report."?

Later: Ah. Here it is:

https://xkcd.com/258/

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@siderea

> Ah, so you're religiously a Manichean?

No, religiously I'm something else.

I just look Manichaean because I'm old, and have observed that the world is... well, let's call it stubbornly sub-optimal & proud of it.

gbhnews, (edited ) to Halloween
@gbhnews@mastodon.social avatar

Is , and for this last Saturday before we are particularly interested in your black cats

But all cats are welcome in our mentions

weekend_editor, (edited )
@weekend_editor@mathstodon.xyz avatar

@gbhnews

This is the Weekend Publisher, providing valuable purr review of my math:

gutenberg_org, (edited ) to books
@gutenberg_org@mastodon.social avatar

"Travellers like poets are mostly an angry race."
Narrative of a Trip to Harar

British explorer and orientalist scholar Richard Francis Burton died in 1890.

He was the first European to discover Lake Tanganyika and to penetrate hitherto-forbidden Muslim cities. He published 43 volumes on his explorations & almost 30 volumes of translations, including a translation of The Arabian Nights. via @wikipedia

Richard Francis Burton @ PG:
https://www.gutenberg.org/ebooks/author/898

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@gutenberg_org @wikipedia

If you're curious about why Project Gutenberg might feel the need to mention that a translation of The Arabian Nights is "unexpurgated", Scott Alexander's hilarious review will clear that right up for you.

https://www.astralcodexten.com/p/book-review-arabian-nights

nblr, to random
@nblr@chaos.social avatar

Hacker leaks millions of 23andme genetic data profiles.

Please resequence your DNA asap, make sure you use at least four different letters and a minimum length of 3.2×10⁹ characters.

https://www.bleepingcomputer.com/news/security/hacker-leaks-millions-of-new-23andme-genetic-data-profiles/

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@nblr

Adenosine, Alanine, Amitryptiline, and Antifascism.

My new genotype is AAAAAA....

gutenberg_org, to science
@gutenberg_org@mastodon.social avatar

German physicist Gustav Kirchhoff died in 1887.

Kirchhoff together with the chemist Robert Bunsen, firmly established the theory of spectrum analysis, which Kirchhoff applied to determine the composition of the Sun. via @Britannica

Several different sets of concepts, concerning diverse subjects such as black-body radiation and spectroscopy, electrical circuits, and thermochemistry, are named "Kirchhoff's laws" after him. via @wikipedia

weekend_editor, (edited )
@weekend_editor@mathstodon.xyz avatar

@gutenberg_org

Also, a copper-cesium deposit on a zinc oxide substrate is a catalyst for the lovely reaction taking carbon dioxide and water to ethanol.

It's also reasonably abundant, but apparently kind of a pain to work with.

X Wang, et al., "Cesium-Induced Active Sites for C–C Coupling and Ethanol Synthesis from CO2 Hydrogenation on Cu/ZnO(0001̅) Surfaces", J. Am. Chem. Soc. 2021, 143, 33, 13103–13112. DOI: 10.1021/jacs.1c03940

https://pubs.acs.org/doi/10.1021/jacs.1c03940

TexasObserver, to news
@TexasObserver@texasobserver.social avatar

For #Newstodon Friday, here's some great #news and #journalism-related accounts to follow on the #fediverse:

@MAD_democracy
@FAIR
@Chron
@TheConversationUS
@damemagazine
@restofworld
@ProPublica
@NewsDesk
@gbhnews
@thetyee
@TucsonSentinel
@longreads
@insideclimatenews
@mnreformer
@UnicornRiot
@dw_innovation
@Windspeaker
@thexylom
@RollingStone

⬆️ No bots on this list 🤠

Just a few of our favs. What are yours?
#FollowFriday #feditips

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@TexasObserver @MAD_democracy @FAIR @Chron @TheConversationUS @damemagazine @restofworld @ProPublica @NewsDesk @gbhnews @thetyee @TucsonSentinel @longreads @insideclimatenews @mnreformer @UnicornRiot @dw_innovation @Windspeaker @thexylom @RollingStone

For biotech & medicine news, it's impossible to beat:

STAT
@STAT

In particular, Helen Braswell

@HelenBranswell

has live-blogged FDA hearings for STAT that were very informative summaries.

mattblaze, to random
@mattblaze@federate.social avatar

Reminder about Mastodon "private" messages. Aside from not being end-end-encrypted (and so visible to instance administrators), they CC anyone @-mentioned ANYWHERE in the body of the message (not just those listed at the start).

They are now called "private mentions" rather than "private messages", but if you don't fully understand the semantics, this behavior may be unexpected and/or cause unpleasant side effects.

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@SteveBellovin @karlauerbach @wollman @mattblaze @sgeo

As I recall it, the Captain was charged by Tenille with harassment, and got exiled to some island with Bob Gilligan.

siderea, to random

I'm looking for a term for something. In rhetoric, there's a term "reductio ad absurdum", literally "reduction to the absurd", whereby one illustrates that one's rhetorical opponent is making a silly argument, by taking it to its logical extremes.

So what's it called, the thing that does, of using more extreme cases to more clearly illuminate principles? For instance, describing moral quandaries in terms of life or death. (Continued)

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@siderea

"Steelmannning" is ALMOST this. It involves addressing the most robust form of an opponent's argument. Here, you're talking about raising the stakes on the argument until it becomes impossible to ignore.

Similar, though not exactly the same. Maybe just "raising the stakes"?

https://en.wikipedia.org/wiki/Straw_man#:~:text=A%20steel%20man%20argument%20(or,not%20the%20one%20they%20presented.

spaf, to random
@spaf@mstdn.social avatar
weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@grrrr_shark @spaf

You came this far. Surely it's worth it to wrap it up a pretty little bow and THEN move on?

johncarlosbaez, (edited ) to random
@johncarlosbaez@mathstodon.xyz avatar

This list of academics on Mathstodon is somewhat useful:

https://github.com/nathanlesage/academics-on-mastodon

But it doesn't list mathematicians or physicists. It does list "theologidons". What's a theologidon? A don who is a theologian?

weekend_editor,
@weekend_editor@mathstodon.xyz avatar

@johncarlosbaez

Apparently "theologidon" is a portmanteau of "theologian" and "mastodon"?

Precedent: the list has a set of academics who study the history of books, nicknamed "BookHistodons".

So far the community has shown remarkable restraint in not making the inevitable pun on "orthodontists". (To my vague disappointment, as I am a Very Bad Person about jokes of that sort.)

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