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thisrod

1,055 karma · joined February 27, 2009

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thisrod··on How Singapore's government-run dating service works
There is an amusing irony in this approach to marriage promotion: who isn't already married in Singapore? I've been told that the city's 30 year old gay and lesbian crowd is treated to a lot of fancy dates at public expense.
thisrod··on The Truth Physics Can No Longer Ignore
This article is profoundly wrong. Physicists and chemists know exactly what life is.

It's a historical contingency, a strange and unlikely one. The reason we're here is that we could equally well not be here, and the universe would get on fine without us. For most of its history, it did. In most places, it still does.

The interesting question is why so few other people know that.

thisrod··on The Hierarchy of Money
Yes. This could be subtitled, "A rational financial system design process: how and why to fake it."
thisrod··on The Radiation Exposure Lie
I think you're being too kind. The article is entirely one-sided. The title says lies, so it's fair game to call the content propaganda.

The facts on low-dose radiation exposure are pretty simple.

There is no useful direct evidence about the health effects of low doses of radiation, and there never will be. It's a needle in a haystack problem: the diseases caused by radiation are common, with large fluctuations; the effects of a small additional dose are small. The article claims that the impossibility of measuring outcomes is a reason to believe that small doses of radiation are harmless. It's wrong. No one knows.

There is watertight, laws-of-physics level evidence about the effects of radiation on biological tissues. There is an expert consensus on how those kinds of tissue damage lead to cancer and other diseases. This evidence supports the linear no threshold model.

The weak link is the pathology: that expert consensus could be wrong. I'm a physicist, so I'm not qualified to hold an opinion. I've never heard a specific reason to think it's wrong.

Those are the ises. For the rest of this post, suppose that the linear-no-threshold model is correct (as the available evidence suggests). The oughts that follow are also very murky.

Everyone is exposed to radiation in their daily life, and lots of lives are shortened by the effects. When you are exposed to a tiny bit of extra radiation, you are a tiny bit more likely to die from radiation; there are much worse hazards that you should worry about first.

When everyone is exposed to a tiny bit of extra radiation, many people will die prematurely. It's universally agreed that those people are just as valuable as other people, exposed to rarer and more spectacular risks, who a lot of money is spent to save. If a few less razors were confiscated at airports, and aircraft occupants were a bit better shielded from radiation, more lives could be saved overall.

Any question like that is bound to be politically controversial.

thisrod··on British Columbia, Time Zones, and Postgres
This problem isn't specific to timezones. In general, you did X on the basis that A was B, and now you know that that A is actually C. The strategies to handle that are quite interesting:

https://martinfowler.com/articles/bitemporal-history.html

thisrod··on Wooden compass with single red arrow leads people with dementia to their homes
People with this level of dementia won't be able to live independently, and there will be someone else to check that.
thisrod··on Ask HN: How do I bridge the gap between PhD and SWE experiences?
I succeeded at this. My academic physics career petered out, then I stumbled into an industry role with almost as much physics as I was doing in my quantum mechanics postdoc.

The jobs you're looking for are rare, but they do exist. There must be a bunch of them in this project, for example:

https://www.abc.net.au/news/2025-12-22/lake-george-earthquak...

In my case, the unicorn factor worked both ways. The job was advertised for a year before my hiking partner encouraged me to apply, and it took a few months more before I did. From that point, the job was easy to get.

In this job market, supply and demand are reasonably well matched; the problem is that the market is very illiquid. Science jobs are rare to begin with, and people stay in them for decades, so vacancies are even rarer.

On the one hand, a programmer at my company who was interested and capable of switching to optics could have had my role by asking for it. On the other hand, if you joined the company as a programmer, you would have had to wait 5 years for an optics role to come up.

So my advice is to stay in touch with your friends from the earth science days, and expect this to take a long time. Good luck!

thisrod··on Australia's tax office lost billions in a simple scam
Original report here: https://www.abc.net.au/news/2025-07-24/no-return:-australias...
thisrod··on DeepSeek releases Janus Pro, a text-to-image generator [pdf]
It's called capitalism. Take one billion times Haiti's GDP per capita, pour it all into a few blocks in Shenzhen, and reinvest the profits.
thisrod··on With 10 months of support remaining, Windows 10 still dominates
Also if you’re using windows on an IoT device…

Microsoft is using IoT in a loose sense. The "thing" could be an industrial PC at the train station that plays a recorded message saying the 8:15 will run late today.

thisrod··on Prevention of HIV
I wonder how much this will cost? A drug you take 2 times a year could be much cheaper than one you take 365 times a year, and that's a big deal.

The existing daily pill is really expensive. Australia knew that PrEP would practically eliminate HIV transmission. Even so, the decision to pay for it took years and was fiercely contested. That was before COVID, and people are more willing to pay for public health today. But cheap PReP would make a big difference in the poor countries where HIV prevention really matters.

thisrod··on Structure and Interpretation of Classical Mechanics (2015)
Thanks!
thisrod··on Structure and Interpretation of Classical Mechanics (2015)
I've finally gotten around to reading SICM, but I can't get MIT Scheme to install on the current OSX 14.2. Autoconf requires an old version of the OSX SDK. Has someone else already solved that problem?

I was surprised by how many ways Sussman and Wisdom found to modernise the Landau and Lipshitz treatment. There is the obvious change, where the first time they solve some equations of motion, it's done numerically, and the solution is chaotic.

There is also a more subtle change, where they keep sneaking in the concepts of differential geometry. The word "manifold" is reserved for a footnote, but if you know what tangent spaces and sprays are, it's straightforward to translate the "local tuples" and see what they're actually talking about.

I think this is a good idea. If physics undergraduates were exposed to manifolds and tangent spaces in their analytical mechanics course, then saw some exterior calculus in their first electromagnetism course, they might be ready for curvature and geodesics when they study general relativity.

thisrod··on AeroSpace is an i3-like tiling window manager for macOS
> in my experience aerospace is way better in most ways.

As an Amethyst user, I'm approaching this comparison from the other direction: is there one compelling reason to switch?

The improvement I'd most like to see in Amethyst is more stable window placement when I remove a monitor then add it again (I do that a lot with my laptop).

It would be fantastic to have integration between Amethyst-managed spaces, Firefox windows, and Proton Pass vaults. As in Space 1 knows that new windows should use the Google account in my Work vault, and Space 2 knows that new windows should log out from Google because there is no Google account in my Personal vault. I doubt that's an imminent prospect, though.

In general, I prefer the Amethyst approach of extending the builtin OSX window management to the Aerospace approach of replacing it. Clearly the Amethyst developers weren't convinced that it's impossible to move windows between spaces with hotkeys, because they went ahead and implemented that.

Overall, I'm really happy that these window managers are being written. I use a 42 inch monitor, which would be awkward without them.

thisrod··on Is something bugging you?
I'm trying to figure out the name. Is it simply a play on Hypothesis, or am I missing something clever about this being the opposite of property-based testing?
thisrod··on British colonialism killed 100M Indians in 40 years
Has anyone read Late Victorian Holocausts, a full exposition of this argument? It's important if true.

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

thisrod··on I’m not convinced by the new lab leak debunking
I'm a bit disappointed that people with little connection to Asia are still making a big fuss about wet markets and exotic animals.

In March 2020, it was natural for people to leap to conclusions, because the only thing anyone knew about the coronavirus was that it "came from" a Wuhan market with weird animals.

Weird is socially relative. You eat pigs and pat dogs. Billions of people think that's weird and a bit gross. Fair enough, seeing how many diseases people have caught from them. Animals can carry germs that are dangerous to people. Wash your hands after you touch them.

Objectively, a wet market is just a slaughterhouse. Here's what, in 2022, you should deduce from the fact that the first large coronavirus outbreak occurred in a slaughterhouse: coronavirus outbreaks occur in slaughterhouses. Obviously some animal carried the virus to the Wuhan market. It's very likely that animal was human, because of all the species there, only humans are known to catch the virus. Even if you found an infected pangolin, you'd have to suspect it caught the virus from its handlers.

thisrod··on The first liquid hydrogen shipment has begun
In one sense, this is worse than pointless. The hydrogen was made from brown coal, so this shipment has caused more greenhouse gas emissions than any other way Japan could have imported that energy. The capture and storage part of this project is still a fantasy, and no doubt it will extend the unbroken record of failure established by all the previous attempts.

It's not doing the people of the Latrobe Valley any favors by playing along with their pretence that coal mining has a future. They might well have a future in electicity storage, but it won't involve digging things up or burning them.

On the other hand, this is an impressive achievement, and it would be fairly straightforward for Australia to generate hydrogen with no greenhouse emissions. The only question is how many governments we'll have to overthrow before we get there.

thisrod··on World No.1 tennis player has his visa rejected and asked to leave Australia
This retired immigration official makes a good point: if Djokovic was suspected of doing anything dodgy, there were lots of opportunities to question him before he boarded a plane. To that extent, it's an Australian stuff up. And the immigration authorities are notorious for stuff ups.

https://www.theage.com.au/national/djokovic-farce-at-airport...

More cynically, this is a great opportunity for the most dishonest prime minister, and most corrupt government, in recent Australian history to put on some theatre about their respect for the rule of law.

thisrod··on World No.1 tennis player has his visa rejected and asked to leave Australia
The details of this are obscure, due to medical privacy, and I don't know more than anyone else.

On the other hand, this isn't the first time that someone has arrived in Australia with a visa, been taken aside at the airport, questioned by immigration officials, and told to leave the country. The usual reason it happens is when the immigration officials suspect that the person told some some fibs on their visa application. To my ears, "failed to provide adequate documentation" sounds very much like a euphemism for "told us a pack of porkies." This would explain the confusion over what the Immigration Department and the Victorian Government discussed after he arrived, and the Victorian Government's rush to distance themselves from him after that discussion.

thisrod··on Entanglement between superconducting qubits and a tardigrade
The biology is even more interesting than I thought. These things have brains, which shut down, then reboot when they rehydrate. Wow!
thisrod··on Entanglement between superconducting qubits and a tardigrade
> not entirely resisting the troll potential here

Entirely possible. The sad thing is, when I've seen physicists take the "no such thing as bad publicity" approach, it's worked. University presidents watch the news too.

thisrod··on Entanglement between superconducting qubits and a tardigrade
So this is me. A decade ago, I would have been a plausible choice of referee for a paper like this.

https://scholar.google.com/citations?user=C6BzRwwAAAAJ

You'll have to take my word for it, as I don't currently have a university job. For some reason, Google doesn't let you authenticate your Scholar account with your ORCID account, even though they trust ORCID to verify that you wrote the papers.

This paper sounds legitimate to me. If it was made up, it would be a fraud, not a spoof. That's unlikely, because the authors come from the most legitimate institutions there are (The University of Oxford, The National University of Singapore). ArXiv verifies institutional affiliation. Even if it is made up, the experiment is plausible.

I can get how it sounds like a spoof. I laughed out loud at:

> We simulate the electric fields and capacitance shifts using ANSYS Maxwell where the tardigrade is modelled as a cube of length 100μm

I.e, they literally assume a cubical tardigrade in a vacuum!

Actually, I did present this experiment as a spoof, at a physics department O-week camp 20 years ago. I think we used a monkey instead of a tardigrade. It was as lame as it sounds.

> My favorite laugh line from the paper: "Maximum likelihood estimation was then employed to prevent the resulting density matrix from having nonphysical properties."

What they did is totally legitimate. Reconstructing density matrices is numerically unstable, a bit like any computerized tomography. This is similar to constraining a noisy CAT scan, to avoid the "nonphysical property" that the air at some point in your lungs has density less than zero.

Engtangling a live animal is a hell of a party trick. No doubt about that. So how much does this matter scientifically? Here we're getting into subjective territory, and what follows is my opinion.

The surprising aspect is biological, not physical. I might have guessed that, if you cooled a tardigrade to the temperature that quantum electronics operate at, you could use it as a quantum electronic component. I wouldn't have guessed that the tardigrade would get up and walk away afterwards!

The philosophical significance? It depends, of course. For materialists like me, who make sense of quantum wierdness the Everettian way, it makes no difference. Of course electrons can get entangled, and the electrons in a tardigrade—or a physicist—are still electrons. (The price we pay is a very, very, odd sense of personal identity.)

For idealists, this is quite a big deal. If you insist that you are a definite state of consciousness, then you need to draw a line somewhere, between the part of the universe that is you, and the other parts that can be quantum superpositions. Twenty years ago, that was easy: you're an animal, not an atom, duh.

This makes it a bit harder: you're a ... big animal? How big, exactly? You could be some non-electronic degree of freedom, but surely that's a stretch neurologically.

It's a lot easier to draw a categorical distinction of animal vs mineral than of human-like observers vs other animals. If they can entangle a tardigrade, then in principle they could entangle your pet dog. Is it much comfort that they can't, yet, entangle you?

thisrod··on Singapore: Sovereign City
> the law really should catch up

Of course it should! My point is that LKY ended up supporting that, so it's a bit unfair to blame him for it not happening. In the context of the article, it matters that the dictator was in favor of gay law reform, and it was fears of electoral consequences that stopped it, or at least provided the excuse for not doing it.

Here's what Australia was doing in the 1990s. Singapore really didn't have much scope to be worse.

https://www.news.com.au/lifestyle/real-life/news-life/the-ni...

> Austrailia decriminalised gay sexual activity in 1973

That is false, or at least highly misleading.

https://www.abc.net.au/news/2015-08-24/timeline:-australian-...

I think Don Dunstan did something in 1973, but I've forgotten exactly what. (It's interesting how many authors still omit to mention that Dunstan was bisexual.) The murder of George Duncan, by persons unknown but widely suspected to be wearing blue uniforms, was 1972. That gave Dunstan his excuse.

The job wasn't finished until 1997, by the conventional account. Personally, I'd argue for 2016, when Queensland[1] made it legal to be a gay teenager.

https://www.queerradio.org/AgeOfConsent.htm

[1] "named for her gracious majesty Victoria Regina, has been inhabited by many who sought to wear her crown" - Clive Moore, Sunshine and Rainbows

thisrod··on Singapore: Sovereign City
> LKY is often called a "benevolent dictator" ... The country’s record on LGBT rights is particularly dismaying

Actually, Lee Kwan Yew spoke in favor of gay law reform in Singapore from 2007. (Which is longer ago than it sounds: Lawrence v Texas was decided in 2003.) It's about the only policy debate he lost: his successors didn't believe that the people would stand for it. And it's easy to forget how bad everywhere else was. Until 2000 or so, I doubt gay life in Singapore was much harder than in Australia.

https://www.reuters.com/article/us-singapore-homosexuality-i...

thisrod··on Australia has officially hit 90 per cent first-dose milestone: PM
This isn't a massive surprise: Australia has 90-95% uptake rates for every other vaccine, and it was never obvious why COVID would be different. (Apart from the Prime Minister getting involved in drug purchasing. That's usually left to professionals, who don't stuff it up.)

https://www.health.gov.au/health-topics/immunisation/childho...

What's a normal vaccination rate for the US or UK?

thisrod··on Concurrency in Julia
This is an interesting point. Julia might well benefit from

    Base.not_understood(f, x::Apple_Count, y::Apple_Count) =
        f(int(x), int(y)) |> AppleCount
with semantics borrowed from Smalltalk. I'm a bit rusty with Julia, please forgive any syntax errors.

I wonder how hard it would be to hack the compiler, catch method not found exceptions, and do that? It wouldn't be fast, but it would work as a proof of concept.

Edit: the semantics I have in mind go like this. If you call f(x, y), where x and y are Apple_Count, but there is no method defined for f(::Apple_Count, ::Apple_Count), then the compiler tries not_understood(f, x, y).

thisrod··on Legacy Train Control System Stabilisation (2012) [pdf]
People say that the Melbourne city loop was the world's first computerized train line. If that's true, this hardware and software had some serious heritage value. It's a pity that Museums Victoria didn't try harder to preserve it when these replacements were made.
thisrod··on The Melancholy of Subculture Society (2019)
> There's a reason large states arose in the first place, to displace hunter-gatherer tribes, and it is precisely this

That's a big leap, from the paleolithic world of 10 000 BC to the iron age armies of 1000 BC. Other things happened too: sedentism, agriculture, metals, buildings, money, writing, and so on. No doubt being able to feed and pay your soldiers made a big difference to their motivation!

thisrod··on Firefox Now Sends Your Address Bar Keystrokes to Mozilla
There's no technical solution to this, short of writing your own browser. Web browsers are big, and there will only ever be a few organisations capable of building one. Like Boeing and Airbus. Those organisations are rich targets for all kinds of shonks, spivs and chancers, who are more motivated than you are. Resistance is as futile as wearing a parcahute on a 737 Max.

There is a time tested and effective political solution: separation of powers. If Abine Blur blocks Mozilla from doing this stuff, and the Firefox plugin auditors keep an eye on what rorts Abine is pulling, then we dumb punters are in with a chance. Abine and Mozilla could gang up, but that puts them in a prisoner's dilemma—either one could win free advertising, then customers, by dobbing the other in to 60 Minutes. Some people are capable of resolving the prisoner's dilemma superrationally, but they don't become shonks, spivs, or chancers, so this is a fairly reliable solution. I think the priority for a privacy respecting internet should be to get Mozilla, Abine, and Duck Duck Go to start acting as if the others exist, and users of any are likely to use them all.

Maybe, in the end, big tech bastards are just another kind of bastard. That would be nice. In 200 years of democratic reform, the people have invented some sophisticated and effective ways of stuffing the bastards back underneath whatever rock they most recently slithered out from.

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