2 hours ago, kenny1999 said:

I have never lived or been to anywhere with a large area of snow, did you mean the image of the whole sun can sometimes been seen on the snow surface?

What if a particular angle of a car where the reflected light is particularly strong? Which usually happens when the light hits directly on the glass of the headlight and reflects.

First I am going to say +1, for actually answering another member.

First time that I can remember.

Then I am going to say that light reflected off snow can lead to a conditions we call snow blindness.

This is not permanent , means that your eye have been looking at a patternless reflection for too long.

They will recover after closing them or looking away at something more normal for a while. 

Photokeratitis (Ultraviolet [UV] burn, Arc eye, Snow Blindness) - College of Optometrists (college-optometrists.org)

1 hour ago, xStFtx said:

I have been researching Quantum Algebra for a few days. I have a few questions about it in hopes that people can help me on here.

1. How do quantum groups differ from classical groups in mathematics?

2. Can you explain the concept of Hopf algebras and their significance in quantum algebra?

 

1)  There is no difference. Groups are sets with a suitable associative binary operation. Some groups have additional structure, eg abelian groups, which have a commutativity requirement. Non commutativity is very important in QM and leads to the uncertainty principle.

Try this postgrad book.

2)  Hopf algebras also explot non commutativity.

https://www.theoremoftheday.org/MathsStudyGroup/SeligHopf.pdf

57 minutes ago, CharonY said:

Your definition for intelligence seems to include simple biochemical processes, as such it does not seem to be a useful definition. I.e. you could as well use the term life or survival instead of intelligence. And none of those are directly linked to evolution. You could survival all you want, but if you do not procreate, it matters little for evolutionary purposes. The premise you seem to make is similarly broad. Everything contributing to survival is consider guidance. This is not only overly broad but also seems to suggest that there is a target that is being guided towards to, without specifying it.

Together, these definitions are immensely unhelpful to discuss evolution, as it mostly ignores the actual connection to evolution, focuses on individuals rather than populations and largely ignores environmental selective pressures as well as stochastic mechanisms of evolution in favour of sliding the term "guided" in.

Not sure what you mean, but I want to emphasize that evolution happens on the population level (i.e. the composition of the gene pool of a given population).

Generations.

Hey folks it after christmas/newyear so I've gotta give this refreshing bit of 2024 sanity a thumbs up.  +1

2 hours ago, exchemist said:

For the second time now in recent weeks, when logging in I get a message towards the bottom of the screen saying "help me", with a note that I have a personal message. This message disappears after a few seconds, without any further keystrokes from me. On neither occasion has there been any unread personal message in my In box. 

I don't like this. Is it a feature, a bug, or has the forum, or my laptop, been hacked? 

Anything like this ?

can you catch a screenshot of your own ?

33 minutes ago, Arthur Smith said:

Goodness me. All life on Earth, ALL life, is on the same branching tree. Admittedly the roots are a little tangled but the evidence is overwhelming.

Perhaps I should make a distinction between shovels and entities such as biological organisms that reproduce.

Tool use (not restricted to humans) evolves adaptively. If you want to access tubers, a stick is handy. A stick that doesn't break is better, a hardened point more so. Observing and learning from others even better. The bias is stronger when the learning is retained over generations. Human cultural evolution has swamped human biological evolution.

How exactly does this address any of my principal points, rather than mocking my attempt as simple examples to help understand them, which you obviously don't.

1) There are several different types of evolutionary process.

2) Not all evolutionary processes involve selection.

3) Selection is itself a complicated process that involves criteria or standards to 'select' against.

4) Darwinian evolution involves what he dubbed Natural Selection, which was another word for the prevailing conditions.

5) For such a process to operate the prevailing conditions must remain sensibly constant for a long enough time.

6) The prevailing conditions can suddenly change (as with the dinosaurs) in the middle of such an evolutionary process.

1 hour ago, Arthur Smith said:

Not sure how much broader the idea could get. Selective bias on populations of reproducing individuals leads to change in time over those populations. Works with shovels, Covid virus, Great Auks, computer memory.

Whilst I agree that selection and evolution can be connected I don't accept that this is always the case.

They are separate distinct processes.

Change over time is another thing again, which I think too large in scope.

Usually the connection is that as small variation of an offspring of a member of a population leads to another slightly different member of that population. For example a smaller or larger elephant with a slightly longer or shorter trunk may have an evolutionary advantage, but is still an elephant.

A dinosaur faced with the external event of the chixelub meteor underwent an entirely different change, although top of the then evolutionary tree.

41 minutes ago, Genady said:

Here this analogy has been developed somewhat further:

Thanks. +1

27 minutes ago, sethoflagos said:

Just to correct some erroneous assumptions made above, the following quotation from Wikipedia entry https://en.wikipedia.org/wiki/Eth is worth reading

The distinction between voiced and unvoiced 'th' has never been made in English by its representation as 'th', thorn or eth. They are simply alternates for the same pair of sounds. It's a common misunderstanding. In principle, you can go through a Beowulf manuscript swapping all the thorns for eths and vice versa, and still claim with some justification that you'd not introduced any spelling mistakes.

 

 

We are all (well nearly all) learning things here.  +1

29 minutes ago, sethoflagos said:

Whether the sound is voiced or unvoiced is governed by a) common contemporary usage (always) and b) the adjacent vowel sounds (usually). Not by its orthography.

Please note my comment about dialect and the pronunciation of the word bath.

Also compare bath and bathilith.

1 hour ago, Spring Theory said:

Well, that's the way I learned how electromagnetic waves work in physics class.

 

etc

So you are using this to preach that you know everything there is to know about these things instead of listening to see what others might know. ?

I asked if you know the difference between a scalar and a vector to try to help you you understand what swnasont and I are both saying, but from different viewpoints.

The positive and negative convention used in an electric field refers to the direction part of the electric field vector, it does not refer to the magnitude.

Charge on the other hand does refer to the magnitude, since charge is a scalar and has no direction.

15 hours ago, Arthur Smith said:

On 12/28/2023 at 12:05 PM, studiot said:

External intervention, deliberate or otherwise.

Would that not be artificial selection?

 I'm sorry I missed this reply.

No it would not be artificial , nor would it be selection in the darwinian sense.

I am suggestng the definition of the word evolution you are employing is too narrow to cover all possible/conceivable circumstances.

3 hours ago, Fermer05 said:

According to the Static Theory of Tides, the lunar tidal wave moves from east to west following the moon at a speed of 1600 km/h, circumnavigating the Earth in 24 hours, flooding only the eastern shores of the continents. 
But centuries later it was discovered. 
1. That the lunar tidal wave floods the western, southern and northern shores of the continents? 
2. That the speed of a tidal wave of 1600 km/hour is destructive for both continents and marine fauna? 3. That there are not two tidal humps operating simultaneously across the globe, but more than a hundred, regardless of the location of the Moon? 
4. That the applied hour, which theoretically should be 50 minutes, was stretched from 0 to 12 hours and serves as a tool for adjusting the lunar theory of tides to reality.

We all know that the Sun, the Earth, the Moon and the terrestrial waters are in motion.

None is static.

So static is the wrong word to use.

We call what you mean by static theory the equilibrium theory and you are correct it was due to Newton, centuries ago.

You are also correct that it is a very crude inadequate model,

But is does correctly identify the forces involved as a combination of gravitational and rotational and that gravitational forces dominate the force part of the equation, but that rotational speeds dominate the timing part of the equation.

A better theory, which also allows for the fact that the rotational axis of the Moon's orbit is not parallel to the Earth's own rotational axis and a few other effects is known as

The dynamical theory of tides.

But this is still based on Newton's force analysis.

As I have shown your figure of 1600 km/hr is approcimately correct.

But I have also shown that it does not correctly model the system as the timing of the moon's periodic function is not the same as the mechanical resonant frequencies of the water.

Do you understand what this means ?

The simplest method of approaching this is to model the hydrographic response as a fourier series rsonant with the lunar driving force, which introduces the humps you mention and use actual observations to calibrate the fourier coefficients to suit.

A yet better mechanical model is to consider the lunar driving force as a 'Forcing Function' with a frequency near to the resonant to a non resonant system.

Are you familiar with the maths of this  ?

It produces frequencies not in the oringinal lunar function nor the resonant response of the hydrographic system.

So to echo swansont's words

Why have you repeated your earlier posting ?

What are you trying to achieve here ?

1 hour ago, StringJunky said:

Only in the dust state, surely? Industrial exposure of the airborne particulates is harmful to lungs. Inside the body's system, it's used for several purposes by it.

They used to add amyl meta cresol or hexachlorophene to toothpaste once upon a time, until it was banned.

What is the form of this 'silica'  it doesn't say.

However I do take your point that it seems to be used in lots of other thing meant for ingestion.

53 minutes ago, iNow said:

 

It happens to the best of us. Don’t let it bother you, please. 

It doesn't bother me, it was just an oddity that sometimes appears on my screen, like that business of the unidentified notification I reported and everyone tried to tell me was my doing until Capt'n sorted it out.

I didn't think to get a screen capture last time it appeared, but I will do next time.

25 minutes ago, Spring Theory said:

What kind of electric field is not associated with a charge convention? Or magnetic field for that matter.

Do you understand the difference between a vector and a scalar ?

You haven't responded to my statement about this.

27 minutes ago, exchemist said:

We cannot know what some suppliers may add to their silicone greases, or fail to remove from them.

Exactly.

Personally I am uncomfortable with the idea that the stated grease is 10% 'silica' , an known carcinogen.

1 hour ago, iNow said:

Right, more likely it was their PaLM 2 or MUM, under the Search Generative Experience moniker (SGE).

My larger point was that ChatGPT is one specific product from one specific company called OpenAI and that it’s extremely unlikely Alphabet/Google are licensing the use of that product put out by a different company for AI generated summaries of their search results. Instead, they’re almost certainly using their own LLM (SGE as earlier noted).

https://www.theverge.com/2023/5/10/23717120/google-search-ai-results-generated-experience-io

I just don't get your point.

22 minutes ago, Janus said:

The same set of lines, just viewed from different perspectives.  In the first image the red line is "taller" than the green, and in the bottom image the green line is "taller" than the red.  The point being that in Relativity, time and space are measured more like the "height" of the lines in the images and not by their absolute le

I've not seen that analogy before, +1

I'm sorry, this is not a proper discussion.

I am reading what you say, and addressing your points, a few of which I agree with a few I disagree with and some are just plain wrong by observation.

You are simply writing longer and longer versions of the false assumptions without answering my questions about observations on reality.

Another plain wrong statement would be

2 hours ago, Spring Theory said:

Current in electrical circuits is a useful thing to tabulate, but at the micro scale, it is still a charge in movement.

If this is an answer to my comment about circuit theory  then it is just plain wrong.

The sign convention for charge (and current) is opposite to that of voltage (potential).

Please answer the questions I have asked instead of ploughing on as if they had not been asked.

13 minutes ago, Spring Theory said:

A positive charge creates a positive electric field...a negative charge creates a negative electric field. Once you see the charge as momentum, the concept becomes clear. Current in electrical circuits is a useful thing to tabulate, but at the micro scale, it is still a charge in movement.

How is this any sort of answer to my points?

In fact all you have done is reiterated my point about the difference between charge and current.

A further question, to emphasis the point raised by swansont.

Every day, throughout the universe, electrons are taking part in chemical reactions, many of which give of photons.

Those atoms concerned along with their electrons, will go on to take part in more chemical reactions up to an enormous number.

If each time this happens how come the charge on the electron does not diminish by the charges you claim now reside in the electric fied of the photons ?

In other words how come the charge on all electrons is not decaying over time in the whole universe ?

Or do you not accept the principle of conservation of charge ?

12 minutes ago, Spring Theory said:

If the source is removed, it disapates.

Not in the case of an EM field it doesn't.

An electron in an atom can emit a photon in the ionisation process and then be destroyed by a subsequent nulcear reaction.

Yet the photon will remain forever or until it is absorbed somewhere else, which ever comes sooner.

What about answers to my questions ?

10 hours ago, Spring Theory said:

Then where is the charge source for a photon's positive field and the source for the photon's negative field?

21 hours ago, studiot said:

I don't agree.

 

So an electric field is generayed by a charged particle, say an electron.

But once the field has left the electron what destroys it, or why can't it exist without the electron ?

 

What in Maxwell's or other equations prevents this ?

A very disappointing response to my polite and pertinent question.

I have another pertinent observation/question.

The assignation/term positive or negative refer to different properties for charge and electric fields.

This is reflected in the fact, often missed, that in electric circuit theory (where we have current not charge) there are two (not one) sign conventions in play.

As a mechanical engineer you should have a good understanding of sign conventions and their implications.

Charge is a scalar. the electric field is constructed from vectors and the sign convention lies in the vector in the latter and the scalar in the former.

13 hours ago, iNow said:

Indeed. Also, my comment above about trust being a major challenge moving forward may have been overly broad and definitely wasn’t restricted solely to SFN

Not Bard?

Or DeepMind?

No I have never seen explicit reference to those invoked.

4 hours ago, Arthur Smith said:

Asking as a dyed-in-the-wool adaptationist, what other mechanisms can be substituted for selection that produce change over time?

External intervention, deliberate or otherwise.

Two things about bots.

This piece of business news

Quote

New York Times sues Microsoft and OpenAI for 'billions'

https://www.bbc.co.uk/news/technology-67826601

Apparantly NYT allege that ChatGPT was trained on many writings that are their copyright and is now regurgitating them, without permission.

and my own recent experience with Google.

I have noticed that when googling a question especially a technical calculation, the top reference is sometimes to a ChatGPT reply and this gradually getting more frequent.

I will post a screeshot next time I get an example

28 minutes ago, grayson said:

I am in the middle of constructing a theory that is specifically focused on iterations.

I am sorry to rain on your parade, but such theory already exists (and has done since Newton's forward and backward difference formulae)

Iterative methods are also called recursive methods in Analysis and Calculus and come in two flavours : Linear and Non linear recursion.
There are also iterated integrals (Fubinis Theorem) and iterated series.