pglpm

joined 1 year ago
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[–] [email protected] 4 points 1 day ago

Well done! 💪🚀

This reminds me: what kind of Youtube replacement or quasi-replacement in the Fediverse? I've heard that Peertube may be difficult to maintain long term, which makes sense...

[–] [email protected] 10 points 3 days ago* (last edited 3 days ago)

This is a fascinating phenomenon – but fully within current theory. And there's no "inversion of the arrow of time", despite what the sensationalistic, misleading title seems to imply. From the recent paper (my emphasis):

Our results, over a range of pulse durations and optical depths, are consistent with the recent theoretical prediction that the mean atomic excitation time caused by a transmitted photon (as measured via the time integral of the observed phase shift) equals the group delay experienced by the light.

The theoretical explanation is given in this paper:

We examine this problem using the weak-value formalism and show that the time a transmitted photon spends as an atomic excitation is equal to the group delay, which can take on positive or negative values.

It is essentially related to the difference between phase and group velocity of waves.

One more example of how nature – as we currently understand it – offers amazing, fascinating, unexpected phenomena. It doesn't need misleading sensationalism.

 

cross-posted from: https://lemmy.ca/post/29254007

https://www.lieffcabraser.com/antitrust/academic-journals/

"On September 12, 2024, Lieff Cabraser and co-counsel at Justice Catalyst Law filed a federal antitrust lawsuit against six commercial publishers of academic journals, including Elsevier, Springer Nature, Taylor and Francis, Sage, Wiley, and Wolters Kluwer, on behalf of a proposed class of scientists and scholars who provided manuscripts or peer review, alleging that these publishers conspired to unlawfully appropriate billions of dollars that would otherwise have funded scientific research."

[–] [email protected] 2 points 3 weeks ago

Personally I disagree on value of sex/nude scenes – but it's a subjective matter of course. Your final argument is absolutely fair and logical, and very general too. Extremely well put – I subscribe 110% to it!

[–] [email protected] 30 points 4 weeks ago* (last edited 4 weeks ago) (3 children)

It's utter bullshit from the very start. First, it isn't true that the Ricci curvature can be written as they do in eqn (1). Second, in eqn (2) the Einstein tensor (middle term) cannot be replaced by the Ricci tensor (right-hand term), unless the Ricci scalar ("R") is zero, which only happens when there's no energy. They nonchalantly do that replacement without even a hint of explanation.

Elsevier and ScienceDirect should feel ashamed. They can go f**k themselves.

[–] [email protected] 5 points 4 weeks ago (2 children)

It seems to me these scenes are introduced in films to sexualize them. Most often than not they don't add anything to the story. But blood & sex get more viewers. So I find the whole thing hypocritical.

Brings me to mind an episode of the hilarious series "Coupling", where Jeff says that the actress in the film "The Piano" (?) was naked in the whole film. His friends say she wasn't, it was only a scene in the film. And Jeff replies "it depends on how you watch it" 🤣

[–] [email protected] 2 points 1 month ago

Agree 110%! It's sad because it pushes back those people who were curious about alternatives and were willing to try. Hopefully things will improve with time...

[–] [email protected] 1 points 1 month ago (2 children)

I've tried different clients: Element web, desktop, and android, and FluffyChat desktop and android. The problems seems to come, as other have written, when the matrix.org server is involved: it's people from their handle there which experience glitches joining rooms in other servers. It seems this "part" of the fediverse still needs a lot of development.

 

cross-posted from: https://lemmy.ca/post/27749197

I've been trying to use Matrix to replace sites like Discord or Slack. But it seems that if a user creates an invitation-only room in a server, then invited users who are registered on other servers get errors when trying to join. Not very useful error messages either: "Failed to join room". (In my case, I tried creating accounts and rooms at nitro.chat and then at converser.eu, but friends registered at matrix.org don't manage to join).

Quite a let-down. Anyone who's facing the same problem and has maybe managed to solve it?

[–] [email protected] 5 points 1 month ago

Looks very promising! thank you for sharing. Seems worth trying and supporting.

[–] [email protected] 4 points 1 month ago

I didn't know about !matrix, cheers!!

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submitted 1 month ago* (last edited 1 month ago) by [email protected] to c/fediverse
 

I've been trying to use Matrix to replace sites like Discord or Slack. But it seems that if a user creates an invitation-only room in a server, then invited users who are registered on other servers get errors when trying to join. Not very useful error messages either: "Failed to join room". (In my case, I tried creating accounts and rooms at nitro.chat and then at converser.eu, but friends registered at matrix.org don't manage to join).

Quite a let-down. Anyone who's facing the same problem and has maybe managed to solve it?

[–] [email protected] 2 points 1 month ago

Which can be further summarized: academics (🙋🏻) are basically a bunch of idiotic sheep, despite being in academia.

See also https://pluralistic.net/2024/08/16/the-public-sphere/#not-the-elsevier

 

Doesn't CrowdStrike have more important things to do right now than try to take down a parody site?

That's what IT consultant David Senk wondered when CrowdStrike sent a Digital Millennium Copyright Act (DMCA) takedown notice targeting his parody site ClownStrike.

Senk created ClownStrike in the aftermath of the largest IT outage the world has ever seen—which CrowdStrike blamed on a buggy security update that shut down systems and incited prolonged chaos in airports, hospitals, and businesses worldwide....

[–] [email protected] 1 points 2 months ago

Fantastic, this is extremely helpful, thank you! 🥇 I wanted to test a couple of distros for my Thinkpad, and I'll make sure to check and save this kind of information from live USBs.

26
submitted 7 months ago by [email protected] to c/opm
 

A new pack of pure Awesomeness is hopefully arriving soon...

1
submitted 9 months ago* (last edited 9 months ago) by [email protected] to c/[email protected]
 

I was reading some works – true pearls! – by Synge: his conference contribution Tensorial integral conservation laws in general relativity (1959/1962) and his book Relativity: The General Theory (1960). In these works Synge introduces an extremely interesting definition of four-momentum and of rotational momentum, based on two-point tensors. The definition is interesting because (1) it involves the full Riemann tensor, not just the Einstein tensor, (2) it includes the (or rather, defines a) four-momentum and rotational momentum of the gravitational field, (3) it obeys a conservation law as opposed to a balance law (the equation ∇⋅T=0 expresses in general just balance, not conservation).

The definition for rotational momentum is also interesting because it appears as the natural generalization of the one in Newtonian mechanics, which is based on the affine structure of its 3D space. Roughly speaking, in Newtonian mechanics we have (r-a)∧p, where a is a fixed point, r the point of interest, and p the momentum (density) at the point r. Synge essentially replaces the difference "r-a", which relies on an affine structure, with the geodesic distance between two points R and A in spacetime, through his two-point "world function". In his book he explains that general relativity requires the appearance of a reference point (a or A) also in the definition of four-momentum, whereas such reference point is superfluous in Newtonian mechanics.

OK this was a very poor summary, just to pique your interest. For details see Synge's conference contribution, and chapter VI, especially §4, of his book (refs below).

Bryce DeWitt even commented "Je suis tout à fait de l'avis du professeur Synge qui insiste sur le fait que ces fonctions de deux points se montreront très importantes dans le futur développement de la théorie de la relativité générale" on the conference contribution. Two-point tensors were quite fashionable in the 1960s, they are used in interesting ways also in Truesdell & Toupin's The Classical Field Theories (see Part F and Appendix III there).

Yet, these definition venues seem to have been abandoned today. Here are my questions to you: why? just for unfathomable sociology-of-science reasons, or because of physical-mathematical ones? Are there works today which further explore these venues?

References:

• Synge: Tensorial integral conservation laws in general relativity, in Lichnerowicz,Tonnelat: Les théories relativistes de la gravitation (CNRS 1962), pp. 75–83. https://libgen.is/book/index.php?md5=74345AB69DDF9EE233FA55F55FDCB057

• Synge: Relativity: The General Theory (North-Holland 1960). https://libgen.is/book/index.php?md5=7AE08880CF8086FED4D3BCF732BE8E54

• Truesdell, Toupin: The Classical Field Theories, in Flügge: Handbuch der Physik: III/1 (Springer 1960), pp. I–VII, 226–902. https://doi.org/10.1007/978-3-642-45943-6_2 https://libgen.is/book/index.php?md5=728F54156B632C44EAC2C559F120DDAB

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submitted 9 months ago* (last edited 8 months ago) by [email protected] to c/[email protected]
 

A little advertisement for a new free online course about the foundations of data science, machine learning, and – just a little – artificial intelligence. It's been designed for students in computer science and data science, who could be uncomfortable with a head-on probability-theory or statistics approach, and who might have a lighter background in maths. The main point of view of the course is how to build an artificial-intelligence agent who must draw inferences and make decisions. As a course, it's still a sort of experiment.

https://pglpm.github.io/ADA511/

In more technical terms, the course is actually about so-called "Bayesian nonparametric density inference" and Bayesian decision theory.

 

Can't help imagining Saitama putting a definite end, without so much back-and-forth, to Mahito's hateful smirk. One punch is all that's needed.

 

What are the comparative and superlative of the adjective "fun"? I'd say "more fun" and "most fun"...

But I'm somehow slightly tempted by "funnier" and "funniest", which should be for "funny" though, not "fun"...

I didn't find anything about this in the main dictionaries.

 

...and thought of randomly posting it here.

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