Today I Learned

[BWV]

If only I could travel back in time and warn my 12 YO self, would have prevented many self-inflicted bruises

 

[pinball1970]

Another child Strep death.

https://www.irishtimes.com/health/2...e-of-bacterial-infection-after-recent-deaths/The article below is less sensational and more measured than some of the other papers.
https://www.theguardian.com/commentisfree/2022/dec/06/strep-a-uk-myths-deaths-children

 

[BillTre]

 

[BillTre]

 

[jedishrfu]

TIL Adam and Eve owned the first computer. It was an Apple. It had one byte. We are still recovering from the first crash, hoping for a reboot, and remembering that on a clear disk you can seek forever.

 

[BillTre]

I recently found a podcast that I am thinking is pretty good.
It is Big Biology.
I would call it a serious biology podcast (as in science for adults).

 

[Ibix]

TIL that there is audio recording of the voice of Helmuth von Moltke the Elder, a man born in 1800 so technically in the 18th century. It was recorded on a wax cylinder in 1889, so the quality is extremely poor.

 

[BWV]

I recently found a podcast that I am thinking is pretty good.
It is Big Biology.
I would call it a serious biology podcast (as in science for adults).

Listened to the last episode during my commute this morning
https://www.bigbiology.org/episodes/2022/12/15/ep-94-synthesizing-life-on-the-planet-with-john-glass

these guys are trying to create the cellular equivalent of a model hydrogen atom - the simplest bacteria cell they can synthesize. They reduced this bacteria to 473 genes, and - surprising to me - biology still does not know what about 1/3 of the genes do.

 

[Hornbein]

Today I learned I didn't know as much about angular momentum as I thought.

 

[Drakkith]

oday I learned I didn't know as much about angular momentum as I thought.

Reminds me of a gyroscope. If it's spinning, it won't fall over.

 

[Hornbein]

TIL the effect of MRI machines on household items.

MRI

 

[BillTre]

Just found out a nice picture of a zebrafish a friend of mine (Dan Castranova) took is getting turned into a US postal stamp in a life magnified series:

the zebrafish is the forth down in the first column.

 

[DaveE]

TIL: Limpet teeth...

are grown as nanometer scale iron oxide (goethite crystals) and are the strongest (tensile strength) biologically produced material, stronger than spider silk. Apparently they may show up in your dentist's practice someday. Lots of interesting details here, if you need an excuse to waste some (more) time.

 

[kyphysics]

We're expected to tip for take-out. . .when did this trend start in America?

In the "old days," take-out orders didn't have a tip expectation.

 

[DaveC426913]

We're expected to tip for take-out. . .when did this trend start in America?

In the "old days," take-out orders didn't have a tip expectation.

"Expected?" Sez who?

I tip when someone brings the food to me.

 

[Rive]

I tip when someone brings the food to me.

Same, but only if there is no 'service charge' on the bill.

... I hate 'service charge'. A tip is supposed to be about feedback too. Service charge feels like upvoting yourself. Simply - cheating.

 

[DaveC426913]

My fam went for a holiday dinner last week. Like, 13 of us. They put a service charge of 15%. (We call it an Autograt.)

I was on the edge of telling our servers I was planning to tip 20% as usual but that they'd taken that decision away from me...

 

[Orodruin]

My fam went for a holiday dinner last week. Like, 13 of us. They put a service charge of 15%. (We call it an Autograt.)

I was on the edge of telling our servers I was planning to tip 20% as usual but that they'd taken that decision away from me...

The concept of waiters needing tips to actually have any sort of decent salary is something that never ceases to baffle me. I don’t stand outside the exam room with a cup for tips at the end of a course.

 

[Ibix]

I don’t stand outside the exam room with a cup for tips at the end of a course.

You should do. With a sign: "Give me a tip and I'll give you a tip."

 

[Drakkith]

The concept of waiters needing tips to actually have any sort of decent salary is something that never ceases to baffle me. I don’t stand outside the exam room with a cup for tips at the end of a course.

My opinion is that it's just an excuse to not pay your employees as much, putting the fault on them if they don't make enough. "Oh, you should be better at your job if you want better pay!"

 

[Ibix]

My opinion is that it's just an excuse to not pay your employees as much, putting the fault on them if they don't make enough. "Oh, you should be better at your job if you want better pay!"

Also if you expect customers to tip 20% then your listed prices are ~17% lower than the customer actually pays. So it looks cheaper than it actually is.

 

[Ahmed1029]

Today I learnt about tensors for the first time

 

[jedishrfu]

MoreTIL on tipping from PBS:

https://www.pbs.org/newshour/economy/why-do-we-tip

and this one on the troubling history of tipping:

https://time.com/5404475/history-tipping-american-restaurants-civil-war/

 

[Orodruin]

Today I learnt about tensors for the first time

 

[Ahmed1029]

Yeah, I've always known the symbols and terminology, but they sounded like witchcraft.

 

[BWV]

Yeah, I've always known the symbols and terminology, but they sounded like witchcraft.

Yeah, found it truly disappointing that I could not use them to commune with the forces of evil.

 

[BWV]

Canada’s Great Slave Lake was taken from the a translation of the Cree term for the lake, as that was Dene territory which they would raid and enslave captives. The Dene, not surprisingly, want the name changed.

 

[Orodruin]

I could not use them to commune with the forces of evil.

Some of my students may tell you that you can use them to commune with their professor …

 

[Ibix]

Yeah, found it truly disappointing that I could not use them to commune with the forces of evil.

You've obviously never said "Euler-Lagrange" three times in a mirror...

 

[Orodruin]

You've obviously never said "Euler-Lagrange" three times in a mirror...

Is your theory not parity invariant?

 

[Ibix]

Is your theory not parity invariant?

Yes it is. The same happens if you say Lagrange-Euler three times in a mirror.

 

[Ahmed1029]

Yes it is. The same happens if you say Lagrange-Euler three times in a mirror.

But it isn't clear whether your theory conserves angular momentum.

 

[Ibix]

Yes it is. The same happens if you say Lagrange-Euler three times in a mirror.

You have to summon Noether to establish that...

 

[Orodruin]

You have to summon Noether to establish that...

If only we had a tool to commune with the dead …

 

[BWV]

If only we had a tool to commune with the dead …

Have to settle for an operator that commutes with the dead

 

[Orodruin]

Have to settle for an operator that commutes with the dead

If the dead Poisson commute with the Hamiltonian they are not likely to change.

 

[berkeman]

TIL that microwave oven turntables can start in either direction (random direction at each start). I've only looked in the oven window a couple of times when starting a cooking cycle, and have been confused by how the rotation direction did not seem consistent. I guess simple AC electrical motors do not have a preferred starting direction...

 

[collinsmark]

TIL that microwave oven turntables can start in either direction (random direction at each start). I've only looked in the oven window a couple of times when starting a cooking cycle, and have been confused by how the rotation direction did not seem consistent. I guess simple AC electrical motors do not have a preferred starting direction...

Yes, not having a preferred direction is a limitation of simple, single phase, AC motors.

This can be overcome by adding additional windings -- "starting windings" -- specifically to bias the starting direction. But this adds complexity and cost, and maybe even efficiency depending on how they're implemented. Household fans/airblowers are a common example of such systems.

3-phase, AC motors don't have such limitations.

 

[BWV]

Yes, not having a preferred direction is a limitation of simple, single phase, AC motors.

This can be overcome by adding additional windings -- "starting windings" -- specifically to bias the starting direction. But this adds complexity and cost, and maybe even efficiency depending on how they're implemented. Household fans/airblowers are a common example of such systems.

3-phase, AC motors don't have such limitations.

Did you check to see if it was manufactured in Australia? Think microwaves rotate clockwise in the Northern Hemisphere and counter in the South

 

[Tom.G]

Yup.
And it saves the manufacturer one turn of 12Ga. wire for the 'Shading Coil,' which can be completely eliminated.

https://en.wikipedia.org/wiki/Shading_coil
(Although I think the article got it wrong about the use in fans! Someone must have gotten confused about the 'stirrer' used in the early ovens to avoid standing waves and dead spots in the oven cavity, they looked a lot like fans with no pitch to the blades.)

 

[nsaspook]

John Cleese's Classic 'Silly Walk' Burns More Calories Than a Normal Gait, Study Finds
BMJ Christmas-week issue

 

[DaveC426913]

John Cleese's Classic 'Silly Walk' Burns More Calories Than a Normal Gait, Study Finds

In the immortal words of Stephen Colbert:

"Hey there, Science. Remember that cure for cancer? How's that comin' along?"

 

[kyphysics]

"Expected?" Sez who?

I tip when someone brings the food to me.

I worry the lack of a tip for take-out results in weird stuff happening to my food.

 

[DaveC426913]

I worry the lack of a tip for take-out results in weird stuff happening to my food.

How? When I go for take-out, I pay when they're handing me my food. It's too late to do anything at that point.

In what circumstance would one ever add a tip before one has actually been served their food?

 

[Hornbein]

How? When I go for take-out, I pay when they're handing me my food. It's too late to do anything at that point.

In what circumstance would one ever add a tip before one has actually been served their food?

Real nice gazpacho we got here buddy. Be a shame if anything were to happen to it.

In his autobiography a gangster revealed that he had to learn a Brooklyn accent in order to be taken seriously.

 

[pinball1970]

TIL Men are rubbish at Xmas?

A rant from two female colleagues complaining that their husbands contributed zero in terms of buying cards and presents for the family.
I was within striking distance and eventually they asked me.
Three relationships of note, I had to admit that my partners did it all.

Like my female colleague's husbands I admitted that I gave money to the partner and they did the choosing and buying.
I signed the cards without reading them and I remember practically begging one partner to take care of it as it stressed me out that much. I really hated it. I don't know when it kicked in, it is like drinking Guinness for the first time and wretching then some time later you are on your 4th pint trying to recall when hate turned to joy.
It just seem to happen.
I did slightly better than one of the husbands who did not even sign the cards.
I feel guilty if they truly despise the exercise as much as we (royal) yet they put up with it.
Noted that this is a FIRST world issue.

 

[Drakkith]

@pinball1970 Yes, I thought it was a pretty well known fact that women often take care of the 'social' aspects of the family. Buying gifts, planning events, etc. I admit that I too often let my fiance do more than her fair share.

 

[Jarvis323]

There is a single cell phytoplanktonic algae that encases itself in a dodecahedron shell.
https://en.m.wikipedia.org/wiki/Braarudosphaera_bigelowii

 

[Hornbein]

There is a single cell phytoplanktonic algae that encases itself in a dodecahedron shell.
https://en.m.wikipedia.org/wiki/Braarudosphaera_bigelowii

As far as I know the icosahedron does not occur in nature.

 

[Borg]

World's smallest D&D die.