azalemeth

21 hours agodiscuss

A nanosecond? The speed of sound at sea level in dry air is approximately 330m/s. So at say 3.3 kHz, the rough logarithmic middle of the audible spectrum, K=2π/lambda is 2π/0.1 m=20 π rad/m. A phase difference from a source difference k. ∆r would therefore likely be far more easily resolved than that for many physical ∆rs then, no?

azalemeth

3 days agodiscuss

I'm a medical physicist. I literally haven't been able to get Fable to answer a question I have written -- all of my work is verboten. I have however asked Claude Code (opus 4.8) to ultracode "a Fable oracle that <deals with the high level difficult problems> in a digraphed, clean content, isolated environment with a minimally scoped working codebase. Ask the model at the start and the end to report exactly what its version string is. If it is not claude-fable-5, stop the agent and refine the prompt until this changes"

It burns through tokens like anything but apparently Claude is much better at prompting Claude than I am.

Would I pay for it? God no. I'm still smarter than I am and it just will not work on my actual problems.

azalemeth

3 days agodiscuss

I still haven't been able to use Fable. I'm a medical physicist -- it just balks at anything I do and gives me an AUP / safeguard error. Applies even if I docstrip out all the comments in my C code!

azalemeth

9 days agodiscuss

For what it is worth, your site has been blocked by the UK's national cyber security centre on my current connection:

    This site may be associated with malicious activity or malware.
     Access to this site has been blocked by the Protective DNS Service
    Site: wtf.korridzy.com
    Please contact your local Network Administrator or IT support if you require further assistance


    Look up this site on Cloudflare Radar [1] for more information.

I would wear this as a badge of pride!

[1] https://radar.cloudflare.com/domains/domain/wtf.korridzy.com

azalemeth

10 days agodiscuss

I'm an international prizewinning academic likely to reduce my hours due to health concerns but very interested in fun, physics-heavy problems and out-of-bag collaborations.

Location: UK

Remote: Yes

Willing to relocate: No

Technologies: Medical Imaging, Magnetic Resonance and biomedical research in general -- and in a more nerdy context, HPC, MPI, C, C++, R, a bit of python (though, frankly, I do not like it) /tensorflow, and bash / mathematica / matlab. Not popular, I know. Oh, and LaTeX. I'll write a shopping list in LaTeX. You probably don't want that.

Website: Have a glance at https://scholar.google.co.uk/citations?user=LhYjunkAAAAJ for a flavour of the many random things I've worked on

Email: See my HN Userpage.

azalemeth

10 days agodiscuss

I haven't bought a single Sony product since then. I used to have a Sony walkman, clock radio, buy classical Sony CDs (or their sub brands), etc, nearly got an original PlayStation.

I wrote a letter to them after the rootkit fiasco saying they've lost a consumer for life. Didn't get a real response. Wrote to them last anti DRM day. Didn't get a response.

Really, this is the only power one has in capitalism -- don't buy their products.

azalemeth

22 days agodiscuss

I know you're joking, but changes in isotopes mildly affect reduced mass and hence enzyme kinetics. Maize and other C4 plants already preferentially enrich themselves with 13C [0-3] which occasionally buggers up metabolomic experiments. Famously, a few drugs use 2H rather than natural abundance H typically in order to exploit a kinetic isotopic effect and get a better Km in their binding pocket [4].

[0] https://en.wikipedia.org/wiki/Fractionation_of_carbon_isotop... [1] https://pubmed.ncbi.nlm.nih.gov/7577891/ [2] https://pubmed.ncbi.nlm.nih.gov/1734681/ [3] https://en.wikipedia.org/wiki/List_of_C4_plants [4] https://en.wikipedia.org/wiki/Deuterated_drug#Examples

azalemeth

25 days agodiscuss

I think it's worth mentioning the likes of tor, lokinet, yggdrasil, i2p, freenet and maybe other "esoteric" forms of networking like vless or v2ray. If they really do put significant barriers in the way of nerd-to-nerd communication, other metrics will only grow really.

At the moment, it's network effects that are the biggest deterrent to using these technologies -- at the moment I don't want to browse eepsites or .loki domains at the moment although I think the technology is interesting -- because the use cases are "normal" consensual porn, horrific illegal porn / CSAM, illegal drugs, and organised crime, none of which are me. If they manage to drive even 0.1% of the population towards talking about, say, cat pictures, unreal tournament matches (gamer-to-gamer communication is itself banned under these proposals without age verification!), or something that normal nerds would like, then (a) the popularity of these methods would explode; (b) the ability of law enforcement to surveil them as proxies for genuinely bad stuff would be significantly hampered; and (c) I think the net result is that more people would be exposed tangentially at least to criminality than before.

It's a shockingly short-sighted proposal. I wrote to my MP about it; her response was basically "We have a difference of opinion".

azalemeth

26 days agodiscuss

Academia is the most relevant, toxic example that I can think of. Be horrible to others on a short term contract (grad students, postdocs) and break them whilst extracting maximum value -- get more papers, more grants written -- more money -- success.

Be nice, think about hard problems for a long period of time, only speak up when you have something positive to contribute -- be labelled an underperforming academic and managed into obscurity.

A great example of this is Peter Higgs, who famously said that he'd be unemployed pretty quickly in the academia of 2013. [0]

[0]: https://www.theguardian.com/science/2013/dec/06/peter-higgs-...

azalemeth

last monthdiscuss

> I saw 'medical physicist' and wondered what you do. Thank you for 'a bit more context', I care! Very interesting stuff. Did you attend medical school + a physics program?

That's a whole separate long answer. I'm not a qualified doctor (and nor would I claim to be), but after a masters' degree in particle physics I moved into an explicitly interdisciplinary training programme that led to a doctorate and at other places in the country I did it in, a separate MPhil. During that initial year I spent a fair amount of time in the dissection room, learning anatomy, as well as most of the first three years (the foundational, preclinical part) of a medical degree combined into one (which contained lots of molecular biology, frankly). My final doctorate was between the departments of condensed matter physics (nominally my awarding institution), biochemistry, radiation oncology, and "the department of physiology anatomy and genetics", which is basically preclinical medicine. The people I work with are 50/50 recovering engineers or physicists, and qualified clinical medics who are trying to learn things like perturbation theory in their time off…

>"it just works", completely by luck What does your validation function look like for this? Whenever stuff "just works" for me I get a little nervous until I determine why.

Ah. I do know why: the relevant Damköhler numbers [0] are either very small (chemistry is much quicker than flow) or large (flow is much quicker than chemistry). So the approximations I am building in are justified and an awkward middle region is excluded; we also are only interested in small concentrations in a carrier fluid (e.g. blood, lymph) where the presence or absence of the species in question does not change its rheology.

I am lucky because we have evolved this way. If our circulatory system and its approach to metabolism was more similar to e.g. a reacting polymer foam ("can of expanding foam") which completely consumes its reactants as it goes, this implicit Lagrangian approach would likely not work.

[0] https://en.wikipedia.org/wiki/Damk%C3%B6hler_numbers

azalemeth

last monthdiscuss

Honestly for a "side project" Opus has been fantastic for me writing a hybrid simulation framework that prior to large scale code generation would have been a matter of years (and writing a grant, assembling a team, etc – in order to do it "properly"). I've had a bit of help with a grad student and I hacking together on a project that is basically "please merge the following GPL codebases and different areas of physics into one coherent environment". I've given Opus validated codes in disparate languages (julia, python, C) and asked for aspects of various algorithms as an extension module to a large chunk of C and C++ code that is a monte carlo simulator that has been around since 2004.

A bit more context if you care: it's a meso-scale, physiological simulation environment of "particles" that carry nuclear spin, can move in 3D space, and (should they interact with each other or their environment) undergo chemical kinetics. The idea is to simulate molecules within e.g. organs or blood vessels within a person in an MRI scanner, with the motion of the particles dominated by the Navier Stokes equations, but here solved in a Lagrangian (rather than Eulerian) framework by smoothed particle hydrodynamics.

The fact that particles carry nuclear spin means that we can solve the (semiclassical) Bloch equations and by using a python plugin module import exactly the physical MRI scanner would do (in pulseq format) and be able to predict what signal the machine would record – e.g. there's a whole world of cardiac or neurological flow imaging work done in the context of nasty diseases like stroke or myocardial infarction – which has a bunch of physical artefacts behind it. I'm trying to make a simulation framework that can take in realistic patient geometries and act as a 'data generating process' because if we do it right the various physical artefacts that the machine records are reproduced, surprisingly accurately. Of course you also know the ground truth of where the particles are. I'm specifically interested in a weird technique (which I did my PhD in and you can read an article all about here: [0]) called dynamic nuclear polarisation, where specific spin states of molecules such as [1-13C]pyruvate are injected essentially out of thermodynamic equilibrium and act as short-lived tracers of metabolism – again highly altered in disease. The signal we record is a strong function of the physics of what you told the machine to do, the spatial constraints and environment of the patient's body, and the chemical kinetics of the patients' biochemistry (the latter two are usually what we're interested in).

Getting them to do chemistry as well as act as a "simple" tracer is more involved, because in the Lagrangian framework the number of particles is ≈ the spatial resolution of your simulation. That's fine if you're simulating water, but if you're simulating something that reacts concentration is not scale invariant (if you want to keep the interpretability of the rate constants). I've worked out an analytic set of scaling rules around this and fortunately for my application environments and length scales "it just works", completely by luck.

I've used Claude to port various SPH algorithms and boundary condition handling ideas (which are absolutely critical and highly not obvious – we have leaky walls in some places, and e.g. LCR / circuit theory models of the microcirculation to plug in) and it's been a godsend. But I'm running into its limitations constantly. It both confidently makes shit up, claims it is mathematically justified and when the resulting simulation explodes says "I apologise; I lied above" (!) or "I apologise; I am wrong" and I periodically have to yell at it to try to do something more productive.

The real hope is that this simulation environment would be both generally useful for basically anyone doing flow MRI, and help our basic scientific understanding of what we're measuring (the technique is in many hospitals!) but also be able to produce meaningful synthetic training data for image reconstruction algorithms later on. It'll end up permissively licensed (all of the "starting" codebases have compatible OSS licenses, and we're releasing our contributions similarly).

I really hoped that Fable would be better at this sort of work. Occasionally, relating to my work DNP [1], I have need to talk about proper nuclear physics and I have seen Opus's chat interface write a wall of text (e.g. talking about photonuclear reactions and cross section differences in millibarn) and then just delete it all. Support have told me that yes, I've hit the nuclear filter and, well, tough shit, basically.

I wrote a version of the above to them yesterday, and just got the most boilerplate response that I've yet to test:

    Thanks for reaching out to Anthropic Support.
   
       We're sorry to hear of the issue that you're running into with accessing Fable 5. I'm happy to say the issue has now been resolved and you should be able to access the model within Claude.

    I'll close this case out for now, but please feel free to reach back out to us here if you have any follow up questions or concerns or if you're still in need of assistance. We'll be happy to help.

which doesn't fill me with hope...

[0] https://physicsworld.com/a/dynamic-nuclear-polarization-how-... [an "accessible" article] [1] https://www.science.org/doi/pdf/10.1126/sciadv.adz4334

azalemeth

last monthdiscuss

I genuinely can't use Fable. I'm a medical physicist. I use the word nuclear a lot. Opus is fine (well, 99% of the time - I've certainly hit the CBRN filters a few times and even been invited to email anthropic about the false positives).

Fable has literally refused to work on any of my problems (even those about fluid dynamics!) and just tells me that I'm violating anthropic's AUP. I've reached out to their support and don't expect to hear anything sensible back. One thing I do look forward to though is OpenAI offering an equivalent model but with less safeguards...

azalemeth

last monthdiscuss

I'm a medical physicist. I use the word nuclear a lot. Opus is fine (well, 99% of the time - I've certainly hit the CBRN filters a few times and even been invited to email anthropic about the false positives).

Fable has literally refused to work on any of my problems (even those about fluid dynamics!) and just tells me that I'm violating anthropic's AUP.

azalemeth

last monthdiscuss

This statistic comes from here -- https://www.gov.uk/government/publications/parental-support-... -- a preliminary analysis of the consultation. The headline statement is:

    "Of the parents and carers of children aged 21 and under who responded to Question 12 on the full-length version of the consultation, 89% supported “a legal requirement for social media services to have a minimum age of access”."

However, what the government (and the media) are _NOT_ reporting is that the consultation also paid an independent firm to undertake a nationally representative survey of adults in the general population. The above document acknowledges this itself, by stating:

    Caveats and limitations

    Users should note the following when interpreting these results: 
    Self-selecting sample

    The consultation was open to anyone who chose to respond. The results reflect the views of parents and carers who were motivated to take part, and are not representative of parents and carers nationally. As with any open public consultation, respondents may differ systematically from the wider population in their views and characteristics. 
    Question routing

    These questions were only presented to respondents who wanted to respond to Chapter 2: Interventions for safer, more positive experiences. All questions in this section were optional. Finally, Question 13 was only presented to respondents who answered “Yes” to Question 12 (i.e. those who supported a legal requirement for a minimum age of access in principle). The 96% figure therefore relates to the level of agreement with a minimum age of at least 16 among those parents and carers who opted to respond to this Chapter and already supported some form of minimum age requirement. It does not represent the views of all consultation respondents, nor all parents and carers who responded.
    Full consultation only

    The figures relate only to the full-length version of the consultation, not the streamlined parents’ and children’s consultations.

Status of results

   These figures should be treated as provisional. A comprehensive analysis of all consultation responses will be published separately.consultation, respondents may differ systematically from the wider population in their views and characteristic

So, it's 90% of 9499 parents who specifically went out of their way to respond to a consultation widely heralded as being predetermined and about blocking access to social media. For context, in the 2021 census (massively disrupted by covid) there were 11.5 million schoolchildren and full-time students whose parents were the target of the survey.

The representative study isn't published yet. The provisional headline 90% number is.

[1] https://www.ons.gov.uk/peoplepopulationandcommunity/educatio...

azalemeth

last monthdiscuss

I'm someone with an academic background who is always interested in new collaborations and interesting problems to explore.

Location: Mostly in Oxford, UK Remote: Yes Willing: no Technologies: Prize-winning physicist and physical scientist. Deeply familiar with maths and physics and statistical inference, in a biomedical context. I've worked on everything from pythons to potatoes (and from assembly code to, well, python). Google Scholar is probably a better judge of my outputs than a strict CV; https://scholar.google.co.uk/citations?hl=en&user=LhYjunkAAA... Email: in profile.

azalemeth

last monthdiscuss

I have specifically chosen AMD _many_ times in the past precisely because of their better linux support and more open toolchain.

This is an absolute foot-gun moment. And the gaslighting PR responses are just unacceptable. I'm very disappointed in them.

azalemeth

2 months agodiscuss

My local library has some dead tree format books with a 500 year support window. Or dead animal or dead reed format books with more like a 2000-year support window.

Planned obsolescence is always bad.

azalemeth

2 months agodiscuss

Exactly. A decent digital communication, spectrum or vector network analyser from the likes of Keysight (AKA HP or Agilent) or R&S is crazy money – many thousands.

Compared to any piece of "proper" test and measurement equipment even if Flipper 1 is $1k it's a steal, for example. Heck, the last thing I put on a grant application was a 220 GHz AWG that was something like $1.5m. Admittedly quite different from a single m2 plugin socket but a 1 GHz spectrum analyser starts at $2.4k and everything fancier is "price on application" [0].

I realise this is not the same piece of kit as Flipper One, but with the right daughter boards, hackability, and <s>graduate student</s> labour I imagine you could do a lot (I am interested in RF at <1 GHz for NMR reasons as well as electronic Larmor frequencies at ~100 GHz frequencies). Their SDR daughter boards are designed for communication but there's a whole world of academic nerds who do weird things and would love a genuinely open, hackable broadband SDR (they exist, with limitations! I have a lime SDR somewhere…)

[0] https://www.rohde-schwarz.com/us/products/test-and-measureme...

azalemeth

2 months agodiscuss

This looks flippin' amazing, but also like the definition of project scope creep. I imagine it will be brilliant, unaffordable, surprisingly cheap, terrible and awesome (in both senses of the word) all at the same time. 3GPP really needs a light shining through it.

I sincerely hope I work out a way of getting someone else to buy the thing for me. And the push towards all in-tree source is fantastic. Genuinely impressed.

azalemeth

2 months agodiscuss

It is perhaps worth highlighting that Mozilla has done this in response to a specific UK government consultation [1] all about "growing up in the online world", which has, buried about 30 pages deep, a specific question about age-gating VPNs and similar technologies.

As far as I can tell, there is no requirement to be a UK citizen to answer this – if you are, were, or could be resident in the UK I urge you to fill it out and help provide a voice of reason...

[1] https://www.gov.uk/government/consultations/growing-up-in-th...

Submissions

Do not ban children from using virtual private networks

Marine Transportation Safety Investigation [Titan] Submersible Implosion [pdf]

GSM, UMTS, LTE and 5G Standard Protocols and Procedures for Lawful Interception [pdf]

Today is the last day of the UK's consultation on social media and VPNs

GradIEEEnt half decent – The hidden power of imprecise lines(2023) [pdf]

[untitled]

Peers vote to ban pornography depicting sex acts between stepfamily members

Apple begins age checks in the UK with latest iOS update

Microsoft Authenticator to nuke Entra creds on rooted and jailbroken phones

Open consultation: Growing up in the online world

Police arresting 1000 paedophiles a month across the UK

Biases in the Blind Spot: Detecting What LLMs Fail to Mention

Do not ban children from using virtual private networks

"Giving children the space to grow"

Grok is still undressing men

Diving into the Depths of Widevine L3

NSA Network Shaping 101 [2007, Snowden leak] [pdf]

(2023) GCHQ [Sigint] Summaries

[untitled]

Games’ affordance of childlike wonder and reduced burnout risk in young adults

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