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fraserphysics

It's a good article about an important subject. Also thanks for the link around the paywall (We dropped the W. Post when Bezos brought in that Brit to run it).

My theory is that the chicken tax makes big pickups etc. the most profitable thing US car companies can make. So they focus on that and relegate everything else to the margins. I suspect that worldwide there will be many more electric sedans than pickups and that, as the article suggests, the US auto industry will end up like the UK auto industry.

Re:A misalignment of AI in mathematics on Friday September 11, 2026 @08:42PM (#49667396)
I don't know how societies set "primary goals". After spending 15 years in a tenure track -- tenured position, I thought setting goals well was important.

I take pleasure in how mathematics and science help me understand the universe better than I understood it before I studied the fields. I believe that my understanding has helped me contribute to society.

Yes! US agriculture (Mostly a red state industry) needs potash. Google AI says that most potash comes from (in order) Canada ("is the primary global exporter and supplies nearly 80% of U.S. imports"), Russia, Belarus, China, and "smaller volumes are supplied by countries [...]".

If I were king of Canada, I would restrict supplies of such materials needed by red states.

Re:Windows 95 released August 24, 1995 on Tuesday August 25, 2026 @11:11AM (#49435539)
I had a summer visiting professor job at Intel at the time doing signal processing. They set me up to use MatLab under Windows95. I installed Linux and code from Numerical Recipes to get around various limitations. Andy Grove had just banned Macs because they didn't use Intel chips. They believed the WinTel duopoly was giving them "more money than God." (A phrase that I first heard at Intel that summer)
That seems like a good idea to me. No matter what the owner says, I would want to know about the incident if I were providing liability insurance on the vehicle.
Sort of related. Across the street from my cousin's house in Portland, OR, a car ran over the curb and into landscape features that knocked off the car's bumper and license plate. The perpetrator then backed up and drove away. My cousin's doorbell camera caught it all. Police are not interested, saying no one can prove who was driving. Who needs a license plate reader when you can get a license plate?
Re:What Happens to an Economy When It's Too Hot to Work? on Saturday June 13, 2026 @09:49PM (#48523405)
The second law of thermodynamics implies that one must spend energy as work to move thermal energy up a temperature difference. So the net effect of an air conditioner is to increase the total amount of thermal energy.
Re:The Countdown to a Major Oil Price Surge Has Begun on Tuesday June 09, 2026 @11:52PM (#48471213)
For a long time I've been reading that the closure of Hormuz is going to constrain consumption soon. I understand the economic theory that reducing supply of an inelastic commodity greatly increases the price. The article says that inventories have insulated us from high prices so far. I am surprised by how large and effective those inventories have been. And I am surprised that futures prices are not higher. Can anyone here suggest explanations?
It was so long ago that I've forgotten most of it. I was impressed that it was based on evidence based literature. Here is a link to the training now https://carpentries.org/instructor-training/ I am disappointed that I don't see a reading list.

Unless it's changed since I was active, The Carpentries does not monetize content.

I signed up for software carpentry instructor training at the SciPy conference in 2015. I expected to learn about their curriculum. Instead, I found that they taught pedagogy. There were articles to read in advance. I should have taken that class before I spent 15 years teaching at university rather than afterwards.
When I worked at Los Alamos, the head of counterintelligence was a former CIA ops guy. He seemed warm and intelligent; just an all around good guy. In presentations, he explained that his job at the CIA was to exploit that appearance to ruin people's lives. He said his approach was to gain the trust of a mark, and then provide him with what ever was required to get him to betray things he loved. The presentations were effective, enlightening and spooky.

So, I agree: All spies are bastards.

Re:The Letter S, by Donald Knuth [pdf] on Thursday May 21, 2026 @12:41AM (#48217950)
This article was in Springer's The Mathematical Intelligencer in 1980. The next article in that volume was "Strange Attractors" by David Ruelle. When I read Ruelle's article in the early 1980s, I noticed Knuth's article. By the time I got to writing my third paper on strange attractors in 1988, I was using TeX.
Re:Helium Is Hard to Replace on Friday April 10, 2026 @06:05PM (#47724206)
Helium will leak out of some structures that hold methane. Shale will trap methane and let helium escape. Layers of salt trap both. Thus horizontal drilling and fracking to recover oil and methane from shale produces very little helium.
Re:Tracy Kidder has died on Tuesday March 31, 2026 @03:35PM (#47592347)
Tracy Kidder's father and grandfather (Henry M. and Henry M. Jr.) were partners in the law firm that's now Seward and Kissel. My great grandfather was a partner in the firm when he died in 1935. I've heard that everyone liked and admired my great grandfather. The Kidders took care of his descendants for the next say 65 years. In 1977 when I got a Bachelors degree in Physics, HMK Jr. wrote a will for me. We met at the Seward and Kissel office to get it signed and notarized, and HMK Jr. took me to lunch at a fancy club downtown. After some martinis, he told me that there'd been two generations of losers in my family, and that everyone thought with my degree in Physics, I could pick up the mantle.

Then he said that he wished his son, Tracy, had an interest in real science like me. When I asked what Tracy was doing, Henry described a silly project of hanging out with computer engineers.

I enjoyed "The Soul of a New Machine" when it came out. I always hoped that I could meet Tracy someday. I guess not. He did great work, I hope his father learned to be proud.

Re:Epstein's Ugly World of Science on Saturday February 14, 2026 @11:25AM (#47015756)
Thank you for articulately describing an ugly part of the world of science that I've seen over the last 40 years. I appreciate your "There but for the grace of God" thought. If I were a bigger star, I can only hope that I would have behaved better than some of those big stars.
Re:The AI boom is causing shortages everywhere else on Sunday February 08, 2026 @12:03PM (#46936197)
After free UNIX and Linux became available on affordable home computers, I found it was no longer necessary to be at a company to do interesting projects. That was before 1995.
Encouraged by the replies here, I tried to get quickemu to setup macOS on my AMD based desktop. The emulated machine crashed trying to boot macOS, and I gave up after a couple of hours.
I thought that macOS was proprietary, and that apple only allowed it to be run on apple hardware. Just last month, I used incus to test a software package in 6 Linux distributions. I want to also test the package in macOS. Must I get a license from apple to do that with Quickemu?
Re:Ask HN: What Are You Working On? (December 2025) on Sunday December 14, 2025 @04:26PM (#46267111)
I'm polishing up the second edition of "Hidden Markov Models and Dynamical Systems." The book explains several state space models and connects them to ideas about chaos. Here's a link to a pdf draft: https://www.fraserphysics.com/book.pdf and here's a link to source for the book: https://gitlab.com/fraserphysics/hmmds Once you install the source software, you can build a pdf for the book by typing "make book". I think that makes it reproducible research.

Show HN: Markov Models and Dynamical Systems – Software and Book

https://gitlab.com/fraserphysics/hmmds

This is a draft of a second edition of this book from SIAM https://epubs.siam.org/doi/book/10.1137/1.9780898717747?mobi...There are three things to show:1. A pdf of the draft: https://www.fraserphysics.com/book.pdf2. The hmm project which provides code for state-space models: https://gitlab.com/fraserphysics/hmm with documentation at https://fraserphysics.gitlab.io/hmm/3. The hmmds project...

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Re:$50 Oil Could Crush American Shale Growth on Tuesday November 04, 2025 @08:17PM (#45817916)
Yes! There's more oil in the ground than we should ever burn. The places where it's cheap to get out are ruled by unpleasant people. Shale limits the price they can charge. Yea shale. However, low prices encourage putting CO2 in the air. Boo shale. I wish we would find a better way to reduce use than paying unpleasant people high prices.
Re:Nobel Prize in Physics 2025 on Tuesday October 07, 2025 @01:37PM (#45506209)
I read the NY Times article about this earlier this morning. I thought it was not very good. I came to HN to see if it had something better. It did. The linked article is also at something like a high school level, but it gave me (retired PhD Physics) a good idea of the experiment and the theory. Thanks.
Please take a look at the most recent draft of my book "Hidden Markov Models and Dynamical Systems" https://www.fraserphysics.com/book.pdf In the first chapter I talk about a chaotic model for laser dynamics, and in the last chapter I use the same ideas to analyze ECGs.

The code and text are at https://gitlab.com/fraserphysics/hmmds. From a Nix command line, "make book" builds the book in about 10 hours.

I'd be grateful for any feedback on the book or the software.

I think it was Larry Summers.
Re:Google's Liquid Cooling on Monday August 25, 2025 @03:20PM (#45017827)
One way to characterize the cost of cooling is entropy production. As you say, cooling is proportional to difference in temperature. However, entropy production is also proportional to temperature difference. It's not my field, but it looks like an interesting challenge to optimize competing objectives.
Re:Why Hasn't Medical Science Cured Chronic Headaches? on Thursday August 14, 2025 @01:54AM (#44897157)
I started getting migraines in the 1960s. Thanks for the link.

While a cup of coffee often helped me feel better in years past, I've found eliminating coffee from my diet has reduced my headache frequency. Triptans help when I get the occasional headache now.

I was disappointed that the article didn't talk about the variety of migraine manifestations. Some of the manifestations can be confused with transient ischemic attacks.

Re:New sphere-packing record stems from an unexpected source on Wednesday July 09, 2025 @12:29AM (#44506356)
I think the result for Gaussian channels is in R^n.
Don't Shannon's channel coding theorem and rate-distortion theorem establish bounds on possible sphere packing?
Re:How to get my ECG data? on Wednesday June 18, 2025 @11:27PM (#44315182)
Thank you for your reply.

I am also not a doctor. I have an appointment with a specialist MD. My PCP was initially alarmed, but after some research and consultations believes that I am not in immediate peril.

Unfortunately the devices that those links point to would not provide 24 hours of continuous data. The data that Phillips won't give me is a continuous record of about 720 hours with a few small breaks. The interesting event was one 2 second interval in the middle of one night.

How to get my ECG data?

I wore a heart monitor for a month and want the data. I've called and exchanged email with "Bio Telemetry, a Phillips company", and all I've received is a stack of paper with a "Daily Patient Report" for each day. (Well I've also received a statement from BCBS saying that they won't pay Bio Telemetry $9,000). My first/primary question to HN is:Do you have advice on how to get the actual...

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