Today I Learned

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In summary: Today I learned that Lagrange was Italian and that he lamented the execution of Lavoisier in France during the French Revolution with the quote:"It took them only an instant to cut off this head and a hundred years might not suffice to reproduce it's...brains."
  • #3,221
Hsopitalist said:
Today I learned that over-enthusiastic gardening can take out an astrophysicist as well as rock stars.
The interesting thing is this Brian May incident's timing seems to coincide with "World Naked Gardening Day," as best I can tell.

World_Naked_Gardening_Day.jpg


https://en.wikipedia.org/wiki/World_Naked_Gardening_Day

But I can't confirm that it's not a coincidence. It would seem reasonable though.
 
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  • #3,222
DennisN said:
Today I learned that you can put ice cream in coffee to soften the taste. I usually use milk, but I tried ice cream today since I did not want to go and buy new milk until I needed more from the supermarket.
One day you can hopefully learn what that means about the quality of your coffees. But did the cream or the milk really help, or did it just add something to make the coffee "better"?
 
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DennisN said:
Today I learned that you can put ice cream in coffee to soften the taste. I usually use milk, but I tried ice cream today since I did not want to go and buy new milk until I needed more from the supermarket.

What flavour? What brand?
 
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symbolipoint said:
But did the cream or the milk really help, or did it just add something to make the coffee "better"?
It helped me at least :smile:. I usually don't like my coffee black.

atyy said:
What flavour? What brand?
Vanilla/Chocolate. A Swedish brand called GB Glace.

The coffee with ice cream tasted a bit like coffee with cream.
 
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  • #3,225
TIL a new word: Nowcasting

I've been attempting to do "nowcasting" for several weeks now, but didn't know there was a word for it. I believe it was the following document where I first found it used:

The Nowcasting created an estimate of the gradient of the number carried out already SARS-CoV-2 disease cases in Germany in consideration of diagnostic, reporting and transmission delay. Building on the Nowcasting the time-dependent reproduction number R can be estimated.

I believe it is a fairly new word, as it doesn't show up in many dictionaries: 2 out of 9 that I checked
 
  • #3,226
OmCheeto said:
TIL a new word: Nowcasting

I've been attempting to do "nowcasting" for several weeks now, but didn't know there was a word for it. I believe it was the following document where I first found it used:

The Nowcasting created an estimate of the gradient of the number carried out already SARS-CoV-2 disease cases in Germany in consideration of diagnostic, reporting and transmission delay. Building on the Nowcasting the time-dependent reproduction number R can be estimated.

I believe it is a fairly new word, as it doesn't show up in many dictionaries: 2 out of 9 that I checked
There should be an established term for it, since it is merely a gliding average, something the chartists among the analysts deal with every day.
 
  • #3,227
fresh_42 said:
There should be an established term for it, since it is merely a gliding average, something the chartists among the analysts deal with every day.
"merely a gliding average" sounds like a very oversimplified phrase for what I've been doing.
I would call it "a menagerie of headache inducing gliding average puzzle pieces, none of which fit the whole."
 
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  • #3,228
OmCheeto said:
I believe it is a fairly new word,
I first heard it six or seven years ago (edit: and the way it was presented suggested to me that it was very nearly brand new then). As far as I understand it's applying textbook forecasting techniques to data that you get with a delay to predict what the data would be for today. So if you get, for example, COVID deaths up to last week then make a one week forecast to estimate deaths up to today, you may call it a nowcast instead of a forecast.
 
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fresh_42 said:
There should be an established term for it, since it is merely a gliding average, something the chartists among the analysts deal with every day.
I think it was called forecasting until someone came up with a catchy name for the specific case of forecasting slightly lagged data up to the present.

As far as I'm aware you are correct that it's just applying standard forecasting techniques (I haven't heard of a gliding average - guessing you've transliterated from German and mean a moving average?). However, you do have to be more aware of the reliability, and lack thereof, of recent data in order to make decent short term forecasts from it. So it's a slightly different context for using those techniques.
 
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Ibix said:
I first heard it six or seven years ago. As far as I understand it's applying textbook forecasting techniques to data that you get with a delay to predict what the data would be for today. So if you get, for example, COVID deaths up to last week, then you make a one week forecast to estimate deaths up to today and call it a nowcast instead of a forecast.
Thanks!
A little more snooping on my part found:

"WSFO Washington's "Nowcasting" program for its local service area..." [Ref: pdf; page 5/20]
circa 1971

So it's at least 49 years old!

Ibix said:
I think it was called forecasting until someone came up with a catchy name for the specific case of forecasting slightly lagged data up to the present.

I think that the use by meteorologists is quite a bit different than how I use it.
They use it to mean "very very short term forecasting".
I use it to determine current infection rates.

My nowcasting is currently based on several assumptions:
1. No one knows how many people are currently infected, due to many factors
2. The CFR is ≈4%
3. The average lag between case detection and death is ≈15 days
4. There are a few more complicating fudge factors, which vary from one locale to another.

So if I know how many people died as of today, I can predict how many people were infected 2 weeks ago, and from the trend of the graph around that period, predict how many people are infected today.

I think a good synonym for it would be "guesstimate".

Which is listed at Merriam-Webster:
Definition of guesstimate​
: an estimate usually made without adequate information​
 
  • #3,231
OmCheeto said:
So it's at least 49 years old!
Wow. I thought it was a lot newer than that.
OmCheeto said:
I use it to determine current infection rates.
This is the context I knew it in - predicting today's data from models of what it will eventually settle to. As you say, it's complicated by data sources that can do different things - some have longer lags than others, or have different reporting times, some don't do weekends, some don't do weekends but do backdate the weekend's data on the Monday, and there may be different criteria for recording something in the first place. You can often gloss over a lot of that with longer range forecasts by regarding the last couple of days as unreliable, but that won't work in this context because it's that unreliability and lateness you are trying to account for.
OmCheeto said:
I think a good synonym for it would be "guesstimate".
My understanding is that when you put this kind of contextual knowledge into a model based on someone's opinion it's called "judgement forecasting". Which sounds better. :wink:
 
  • #3,232
Ibix said:
I think it was called forecasting until someone came up with a catchy name for the specific case of forecasting slightly lagged data up to the present.

As far as I'm aware you are correct that it's just applying standard forecasting techniques (I haven't heard of a gliding average - guessing you've transliterated from German and mean a moving average?). However, you do have to be more aware of the reliability, and lack thereof, of recent data in order to make decent short term forecasts from it. So it's a slightly different context for using those techniques.
Yes, it is gliding in German. I didn't look it up since it made perfectly sense to me to call it gliding instead of moving. I follow the press conferences of the RKI here and they explained what they do, so it is indeed a moving average what they calculate. They once explained that they widened the step size from 2 to 4 days in order to smoothen the weekend delays. It's also an average built over the entire country, which means that local data can vary a lot. Politics is trying to implement local criteria now as a benchmark for local quarantine measures.
 
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TIL that the entry in the church baptismal book in Kiel reads: Marx Karl Ernst Ludwig Planck.

However, the "r" has never be seen again except on a copy for the baptismal certificate. When he was ten, he already signed a letter with Max. When and why the name changed is unknown. One possible explanation - and favored by me - is an early adaption to local habits in Munich, where Max was and is much more common.
 
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  • #3,236
fresh_42 said:
TIL that the entry in the church baptismal book in Kiel reads: Marx Karl Ernst Ludwig Planck.
Max Planck = Karl Marx :oldbiggrin:
 
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  • #3,237
Demystifier said:
Max Planck = Karl Marx :oldbiggrin:

Groucho, Chico, Harpo(, Gummo, Zeppo) and of course Planck.
 
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  • #3,238
When I was at school, mnyah mnyah, hand calculators had not been invented, and we were taught how to more conveniently multiply and divide numbers using logarithms to base 10 so that instead of multiplicationsand divisions you did notably easier additions/subtractions of the logs - all explained here https://en.wikipedia.org/wiki/Common_logarithm#Mantissa_and_characteristic
as maybe nowadays this is not taught? To do this you needed to get the logs, which you found in tables, an example is illustrated in the above link. (Then after adding the logs you needed to convert the resulting log back into a number it was log of. It comes back to me that although there were 'antilog' tables for some reason we did not use them but looked them up in the same log tables and were taught a trick called 'interpolation'.) How anyone had been able to calculate the tables was not on the syllabus and we did not ask.

Now to finitely tabulate a function for any possible input it needs to have some kind of repetitive character. For example tables of trigonometric functions only need to go up to 90 degrees, tables of square roots, which we also had, need only go from 1 to 100. So, for instance, log10 2 = 0.3010 to 4 decimal places. And that's all the table tells you. However if you need e.g. log10(2×104), knowing what logs are you know that is 4.3010. If the number is less than 1 the log is negative, e.g. log10(2× 10-4) is -4 + 0.3010. but you didn't combine these into a single negative number, it was unnecessary. In a multiplication for instance you just added the various logs algebraically, added up the positive part after the decimal point, carrying over as in normal addition, and then added algebraically the integers before the decimal point.

I just went into this because I guess it is not taught nowadays, no longer really being useful, so maybe readers don't know it. But there was a question about it in homework help yesterday "Logarithm calculation by hand" and this stuff which I have not needed for decades came back to mind. Well, I learned it not exactly today but a very long time ago, about age 11 or 12 – even a bit depressing to be still talking about it now, doesn't feel like progress. So what's new?

Well, the part after the decimal point like .3010 above was called the 'mantissa'. Funny word, I have never heard that used in any other context and I don't suppose any of you have either. It is not obviously connected with anything else – I mean I can't think of anything less connected with all this than a mantis.

So now, TIL that "decimal part of a logarithm," 1865, from Latin mantisa "a worthless addition, makeweight," perhaps a Gaulish word introduced into Latin via Etruscan (compare Old Irish meit, Welsh maint "size"). So called as being "additional" to the characteristic or integral part. The Latin word was used in 17c. English in the sense of "an addition of small importance to a literary work, etc."

I thought, from the above dating that the word might have been coined by Briggs himself. But the OED gives for first use 1865! It sounds then invented by some Victorian pedant. In which case its present oblivion is fully deserved.

Surprisingly the word 'mantis' seems also a 17th-century scholarly origin.
Modern Latin, from Greek mantis, used of some sort of elongated insect with long forelimbs (Theocritus), literally "one who divines, a seer, prophet," from mainesthai "be inspired," related to menos "passion, spirit," from PIE *mnyo-, suffixed form of root *men- (1) "to think," with derivatives referring to qualities and states of mind or thought (compare mania and -mancy). I find it surprising the highly remarkable insect has no older popular name.

That's what I think I learned today – but I'm not really confident it's all 100% correct.
 
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TIL, well re-learned, about the historical term "doughface" in the context of pre Civil War American politics. Not to be confused with 'doughboys' in later wars, doughfaces referred to Northern politicians who outwardly supported Southern causes and/or voted for legislation that supported slavery and against legislation that favoured abolition.

While the premise of this thread could use work, many responses discuss interesting history.
 
  • #3,240
Demystifier said:
Max Planck = Karl Marx :oldbiggrin:

No wonder you never see them together in the same place at the same time!
 
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  • #3,241
diogenesNY said:
No wonder you never see them together in the same place at the same time!
4254118ee7ce307c18035e712f9710f8.jpg
 
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TIL If you use the small angle approximation twice, it magically becomes exact again $$\int_0^{\frac{\pi}{2}} \cos{\theta} \, d\theta \approx \int_0^{\frac{\pi}{2}} 1 \, d\theta = \left[\theta \right]_{0}^{\frac{\pi}{2}} \approx \left[\sin{\theta} \right]_{0}^{\frac{\pi}{2}} = 1$$ It works for this one, so it's got to work for all of them, right? :wink:
 
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$$\int_0^{\frac{\pi}{2}} \cos{\theta} \, d\theta \approx \int_0^{\frac{\pi}{2}} 1 \, d\theta = \left[\theta \right]_{0}^{\frac{\pi}{2}} \approx \left[\tan{\theta} \right]_{0}^{\frac{\pi}{2}} = \text{... wait}$$
 
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  • #3,244
mfb said:
$$\int_0^{\frac{\pi}{2}} \cos{\theta} \, d\theta \approx \int_0^{\frac{\pi}{2}} 1 \, d\theta = \left[\theta \right]_{0}^{\frac{\pi}{2}} \approx \left[\tan{\theta} \right]_{0}^{\frac{\pi}{2}} = \text{... wait}$$

And that concludes our proof that ##\infty = 1##!
 
  • #3,246
Today I learned the difference between Mitä and Mikä in Finnish.

As of recent, I taken a new interest in learning the language of my ancestors. I grew up hearing it spoken on a fairly regular basis, but never really learned it other than a few scattered words.
Mitä ( the ä is pronounced like the "a" in hat.) is one of the ones I thought I knew. It meant "what".

But I was seeing "mikä" being used for "what", and began to wonder if I had been hearing it wrong ( all my exposure to Finnish was via spoken word)

Today I learned that both words mean "what". It's just that they are used in different contexts.

Both
Mikä tämä on? and Mitä tämä on? mean "What is this?
But the answer you get would be different.
In the same situation,
"Mikä tämä on?" might get you the answer: "Tämä on pöytä." ( this is a table.)
While
"Mitä tämä on?" could get you an answer of "Tämä on tammi" (this is oak)

Mikä means means you are asking about the object, While mitä refers to what it is made of.

In essence Mikä is about a concrete object, while mitä is about substance or something abstract.

"Mitä tämä on?" could also give you answers like "Se on kahvia" ( "It's coffee" ), or "Se on rakkautta." ( It's love)

So, "Tänään opin" ("Today I learned ") that I hadn't heard it wrong after all.
 
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  • #3,247
Today I learned (actually contemplated) that hate is always reciprocated but love seldomly.
 
  • #3,248
Today I learned that Finnish needs an ä in every other word, at least if the small sample above is representative. It has 11 Finnish words, 5 of them have an ä, including one with two ä and one with three ä.
As a German I'm familiar with that letter, but it's not that common in German.
 
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  • #3,249
Janus said:
Today I learned the difference between Mitä and Mikä in Finnish.
Not completely.
Janus said:
Today I learned that both words mean "what".
In your context, yes.
Janus said:
"Mitä tämä on?" could get you an answer of "Tämä on tammi tammea" (this is oak)
Was that a typo? "Tämä on tammi" could be answer to "Mikä tämä on?"
Janus said:
"Mitä tämä on?" could also give you answers like "Se on kahvia" ( "It's coffee" )
One can also say "Se on kahvia mikä maistuu hyvältä" ( "It's coffee which tastes good" ).
One would not say "Se on kahvia mitä maistuu hyvältä".
Janus said:
So, "Tänään opin" ("Today I learned ") that I hadn't heard it wrong after all.
Right.
 
  • #3,250
forcefield said:
Not completely.

In your context, yes.

Was that a typo? "Tämä on tammi" could be answer to "Mikä tämä on?"

One can also say "Se on kahvia mikä maistuu hyvältä" ( "It's coffee which tastes good" ).
One would not say "Se on kahvia mitä maistuu hyvältä".

Right.
Bear with me. I've just delved into this in the last couple of weeks. I know my explanation of the difference was most likely incomplete.

And if I make some errors in forming phrases it is due to my lack of experience with the language. While both of my parents did speak it, having learned it from their immigrant parents, they did not pass this knowledge onto us kids. As I said, my knowledge up to now has been limited to what it sounds like, and a handful of words. (Like how to properly pronounce "sauna". )

So, I think were I erred was, and correct me if I'm wrong, "tammi" would be used to refer to "an oak" ( as in an oak tree), whereas if I meant the type of wood something was made of, you would use "tammea"?
 
  • #3,251
Janus said:
So, I think were I erred was, and correct me if I'm wrong, "tammi" would be used to refer to "an oak" ( as in an oak tree), whereas if I meant the type of wood something was made of, you would use "tammea"?
Yes, "Se on tammea" means that it is made of oak. I wondered because all your other Finnish sentences were correct. My main point though was related to the usage of the words "mikä" and "mitä".
 
  • #3,252
forcefield said:
Yes, "Se on tammea" means that it is made of oak. I wondered because all your other Finnish sentences were correct. My main point though was related to the usage of the words "mikä" and "mitä".
Like I said, I'm early in my learning phase. And it really isn't a structured course, but a little "hit and miss".
I was actually very pleased with myself by the fact that when I saw the following example of the use of Mikä, without any translation given:

"Mikä sinun lempiväri on?"
"Minun lempiväri on punainen"

That I was able work out that it translated to
"What is your favorite color?"
"My favorite color is red."
Based on that I knew "sinä" was "you", "minä" was "I", "väri" was "color" and "punainen" was "red".
This is leaps and bounds beyond what I could have done just three weeks ago.
 
  • #3,253
zoki85 said:
Today I learned that TV makes people more fat than they are in real.

I think this may be because the focal length of the lenses used in studios is often on the short side, to make use of studio space and for 'intimate shots'. That's not what you'd use for a flattering portrait - for standard 35mm negative, 80mm portrait lenses are favoured, compared with the standard 50mm. So this gives the impression that cheeks and jowls are bigger than you'd expect and, hence, you can't see as far round the sides of faces. An illusion of fatness. This could also apply to tummies too. (Also noses!)
 
  • #3,254
about Google's database center
 
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Today I learned the term battler, meaning underdog; a person of modest means who strives to improve themselves.

At first I thought battler meant a war veteran in keeping with my state motto "Battle born!". Stripped of political connotations in keeping with PF policy, according to the cited article the Australian term refers affectionately to the low and middle caste in democratic society who battle or struggle to survive.

I imagine battler might refer to many PF users who strive to learn, help others learn and to communicate knowledge regardless of social standing.
 
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