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David Sloan @davesmaths.bsky.social · 30/09/2026

I agree. As a case in point a recent paper of mine had a subtle but important error that was pointed out within a week of the paper being on the arXiv, and therefore corrected before submission to a journal. It beat waiting months for a revision, or even a rejection, based on this. If caught at all!

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David Sloan @davesmaths.bsky.social · 30/09/2026

That's a hell of a claim. In the areas I work, peer review can mean a 6 month or even year long lag time between submission and acceptance. When I got my first postdoc I had unpublished work on the arXiv (which was later accepted) that I relied on in applications. I'm sure other ECRs are the same.

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David Sloan @davesmaths.bsky.social · 30/09/2026

Yes, I know THE and Times aren't technically the same thing, but if two orderings disagree so wildly with one another, how can we trust any of them?

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David Sloan @davesmaths.bsky.social · 30/09/2026

A partial order on a subset obeys the partial order on the parent set. Hence we must be forced to conclude that this university ordering is mathematically ill defined and therefore worthless.

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David Sloan @davesmaths.bsky.social · 30/09/2026

Oxford University is the best in the world (Times Higher Education World Rankings 2027) yet 5th best in the UK (Times University Guide 2027). St Andrews at no.1 in the UK and ranks it 185th in the world. Behind 23 other UK institutions.

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David Sloan @davesmaths.bsky.social · 29/09/2026

If you've never heard a fire alarm at work it isn't because there haven't been any fires. It's because your institution didn't install smoke detectors.

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David Sloan @davesmaths.bsky.social · 28/09/2026

From their own article "St Andrews, ranked second in the Guardian’s university league table for 2026, accepts one of the highest percentages in the UK of privately educated students. " St Andrews was just ranked top of the Times UK university rankings.

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David Sloan @davesmaths.bsky.social · 27/09/2026

Newspaper publishes "University Guide" that correlates high scores with middle/upper class students. Newspaper is then shocked to find classism rampant at one of its top ranked institutions. www.theguardian.com/education/20...

theguardian.com

‘It’s like the Scottish Upper East Side’: shame and snobbery as American students blamed for St Andrews classism

Online comments reflect class tensions at Scottish university between those from lower-income families and wealthier US undergraduates

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David Sloan @davesmaths.bsky.social · 24/09/2026

That must hurt. The part where they talk about two different models as though it's supposed to be somehow reassuring is just an extra kick in the teeth: "We read both tea leaves AND entrails for robustness".

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David Sloan @davesmaths.bsky.social · 10/09/2026

You mean other than anyone submitting to an academic journal? ;-)

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David Sloan @davesmaths.bsky.social · 07/09/2026

And good luck to anyone trying to lecture in this disaster of a room. Why is it that academic architecture seems to be designed to actively impede academics?

And image of a ridiculous lecture theater - open top so sounds travel, circular so there's no way to focus on a board, flat with terrible looking uncomfortable chiars, pillars in the middle of the room. Effectively a designed torture chamber for anyone unlucky enough to teach in it.

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David Sloan @davesmaths.bsky.social · 06/09/2026

Yep. Used to be I'd just get general "Here's a bunch of stuff about me..." emails. Now they've started giving obviously AI generated reasons their research relates to mine. And the students. Beyond infuriating - questions either answered in the papers, or so technical they don't understand them.

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David Sloan @davesmaths.bsky.social · 06/09/2026

Very much this. I don't teach my students so they know physics, I teach them so they can think like a physicist*. * An idealized physicist. In a vacuum. I know how some of my colleagues actually think...

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David Sloan @davesmaths.bsky.social · 04/09/2026

I'll keep busy by reading the thousands of media articles about academic malpractice by demographically overrepresented Oxbridge professors from who have been found out recently. They're sure to keep me busy, right?

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David Sloan @davesmaths.bsky.social · 04/09/2026

I'm patiently waiting for the deluge of "All the jobs have been given to less qualified applicants who only got the position because they are sexual harassers" complaints. Bets on whether they get here before Godot?

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David Sloan @davesmaths.bsky.social · 02/09/2026

When you ask me what's wrong with #science in #academia, you get a rant. Thankfully the excellent editors at @bigthink.com made it coherent. #academicsky 🔭🧪

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Reposted by David Sloan

FQxI @fqxi.org · 01/09/2026

Science needs people who can afford to be wrong. Yet we seem to have built a career ladder that removes them. [VISUAL THREAD]

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David Sloan @davesmaths.bsky.social · 27/08/2026

So I guess the mnemonic for the great lakes will need to be updated from HOMES to SHAME.

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David Sloan @davesmaths.bsky.social · 26/08/2026

An excellent volume, with work by great researchers at the interface of physics and philosophy. And some weird guy who kept going on about cosmology.

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Reposted by David Sloan

FQxI @fqxi.org · 21/08/2026

Jordan Scharnhorst is one of our new FQxI Fellows. He’s joining us for Foundational Answers, a programme taking stock of progress on 10 major topics in foundational science and identifying the questions still open. A part of that work is adversarial collaboration. Jordan explains what that means.

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David Sloan @davesmaths.bsky.social · 12/08/2026

Absolutely - looking historically emphasises both the need for repeated experiments and tests of independent predictions of the theory.

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David Sloan @davesmaths.bsky.social · 12/08/2026

To get the Einstein deflection, you have to find the geodesics of the Schwarzschild metric for a null geodesic. It's easiest to do this on a plane using radial coordinate u=1/r and angular coordinate phi, finding paths where u->0 (r-> infinity).

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David Sloan @davesmaths.bsky.social · 12/08/2026

To get the Newtonian deflection, set up axes so that the light is initially travelling along the x axis, with closest distance of this straight line to the sun being aligned with the y axis. Then integrate the total Newton force along this path to get the change in y momentum.

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David Sloan @davesmaths.bsky.social · 12/08/2026

The physics is a little more subtle than on first glance, as negligible (but non-zero) mass photons travelling at a finite speed would also be lensed by Newton's theory but not as much. In doing the calculation right, up to some approximations of large distances, GR gives twice the deflection.

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David Sloan @davesmaths.bsky.social · 12/08/2026

Total eclipse today - the 1919 eclipse was the first big demonstration of gravitational lensing, with GR getting the "right" amount of lensing, beating the Newtonian prediction. If, like me, you thought the Newtonian prediction should be zero, well, read on...

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David Sloan @davesmaths.bsky.social · 11/08/2026

To be fair it has appeared on the Guardian's website: www.theguardian.com/education/20... “In one example the person being complained about drafted the response to the claimant rejecting his complaints against them.” How could this ever be considered a good idea?

theguardian.com

University of Cambridge whistleblower who reported alleged bullying wins employment tribunal

Prof Wyn Evans, who raised concerns over treatment of female staff at Institute of Astronomy, was subject to ‘baseless’ investigation, judge rules

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David Sloan @davesmaths.bsky.social · 10/08/2026

Wonder if this will get the same level of media attention that other Cambridge news always seems to get.

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David Sloan @davesmaths.bsky.social · 10/08/2026

Celeste's story was brillaint, start to finish. But I wouldn't let that set expectations for a next game. The same group made The Talos Principle (epic) and Serious Sam (pure kitsch). Portal (great) and Team Fortress (Plot: Red vs Blue - fight!) even came as part of the same collection.

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Reposted by David Sloan

FQxI @fqxi.org · 07/08/2026

Some physicists believe that the future can influence the past. For someone hearing that for the first time... it sounds pretty crazy. We spoke briefly to Matthew Leifer about how that can possibly be true!

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David Sloan @davesmaths.bsky.social · 03/08/2026

To be fair, that's how paper* used to work. * yes, I know, in a generic sense of the word.

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David Sloan @davesmaths.bsky.social · 31/07/2026

"You've been poisoned. Would you like one dose of antidote or to play the roulette wheel for 100 doses?"

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Reposted by David Sloan

Food Security for Equitable Futures @foodequity.bsky.social · 30/07/2026

🍸 Three #FlashFinding cocktail punches on #FoodSecurity in post-COVID India. Fast, evidence-based insights on how households coped & what this means for food systems and policy. 📽️ ✔️ youtube.com/shorts/Liq1U... ✔️ youtube.com/shorts/CSvdJ... ✔️ youtube.com/shorts/wL2hT... #Nutrition #India #COVID19

youtube.com

Covid-19 and Food Insecurity - Flash Finding#1 🍽️

YouTube video by Food Security for Equitable Futures

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David Sloan @davesmaths.bsky.social · 30/07/2026

If you have no divisors I will find you, prime after prime.

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David Sloan @davesmaths.bsky.social · 29/07/2026

One of my favourite places in the world.

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Reposted by David Sloan

FQxI @fqxi.org · 23/07/2026

A corridor chat with Chris Smeenk, professor at @westernu.ca, about correcting common misunderstandings about the Big Bang and the early universe. Chris' research centres around the scientific method and the nature of our knowledge of physics.

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David Sloan @davesmaths.bsky.social · 09/07/2026

I just see "deleted" for the post you're quoting. Is there good news?

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David Sloan @davesmaths.bsky.social · 30/06/2026

If you haven't seen it already, check out the Multiverse mod. It's the closest thing to FTL2 - a huge expansion on the original. www.subsetgames.com/forum/viewto...

subsetgames.com

[OVERHAUL - USES HYPERSPACE] FTL: MULTIVERSE Version 5.5.1 Stars and Stripes - Subset Games Forum

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David Sloan @davesmaths.bsky.social · 10/06/2026

Makes more sense if you read it in the voice of Zapp Brannigan.

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David Sloan @davesmaths.bsky.social · 10/06/2026

The curvature satisfies the Bianchi identity. It is left to the reader to determine if it also satisfies the Bianchi supremacy and the Bianchi ultimatum.

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David Sloan @davesmaths.bsky.social · 31/05/2026

It's a constant battle in the Guardian for who can make me want to donate less.

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David Sloan @davesmaths.bsky.social · 27/05/2026

Captain of Titanic advises increase speed and ignore icebergs.

Headline: "Tony Blair tells Starmer and rivals: abandon net zero and move closer to Trump"

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David Sloan @davesmaths.bsky.social · 17/05/2026

And it happens again - original email 9:12 PM on Friday, harassing follow-up 9:12PM on Sunday. You won't believe how fast I declined that one. Journal editors: if you do this, you contribute to a culture of overwork and poor mental health, and I will NOT sacrifice that for you.

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David Sloan @davesmaths.bsky.social · 14/05/2026

I'm all in favour of not allowing LLM generated content. Given the central role that arXiv plays in modern physics communication they had better be sure that they are right, and have genunine transparency in their moderation process. A false positive could be devastating to a PhD student's career.

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David Sloan @davesmaths.bsky.social · 14/05/2026

Everything going according to plan for Starmer...

Two headlines next to each other. First reads "Wes Streeting prepares to lauch leadership challenge against Keir Starmer" from 4h ago. The second "Starmer has 'full confidence' in Streeting despite health secretary's allies saying he is planning to resign - as it happened" from 6h ago.

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David Sloan @davesmaths.bsky.social · 12/05/2026

Getting ready to teach: Lecture written PDF on flashdrive Double-checked it's available online to the students Got my notes Grabbed my laptop Jacket on, leave house, get in car Realize I'm still wearing slippers. It might be a rough one today.

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David Sloan @davesmaths.bsky.social · 08/05/2026

Do you like general relativity but find the Einstein-Hilbert action just too conservative for your taste? Now on the arXiv: arxiv.org/abs/2605.05817 More excellent work by my PhD student, in which we show that the conformal factor can be removed in favour of friction.

arxiv.org

Classical General Relativity as a Non-Conservative Action-Dependent Field Theory

Scaling symmetries have previously been examined for classical field theories described by singular Lagrangians; in this article, we apply these results to the first-order formulation of General Relat...

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David Sloan @davesmaths.bsky.social · 05/05/2026

Penrose already nicked that one for twistors - arxiv.org/abs/hep-th/0...

PDF in which we read

"We want to understand the − − − + + amplitudes in
the “original” twistor space with homogeneous coordinates λ, µ. In the language of twistor
theorists, we want to understand the “googly” description of the − − − + + amplitudes.
(The term is borrowed from cricket and refers to a ball thrown with the opposite of the
natural spin.)"

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