manvillej (u/manvillej)

manvillej commented on Good Justifications Write Themselves oblique.security/blog/jus... · Posted by u/mooreds

manvillej · 7 months ago

I think this is a step forward, but I think it is better to think of access in terms of what responsibilities a person or group has.

When new access is to be given, it should be framed in the context of what new responsibilities are required.

I think this framing provides not just justification, but can provide inherent expectations of a users behavior that is easier to inspect and interrogate if needed.

manvillej commented on Tips for mathematical handwriting (2007) johnkerl.org/doc/ortho/or... · Posted by u/susam

bluenose69 · a year ago

This is a good resource, and pretty much what I tell students in my classes. I take great care to explain how to write symbols, and I also give multiple pronunciations of the Greek letters.

Students with math and physics backgrounds are fine with Greek letters and other mathematical symbols, but the biologists in the class are mystified. They also get terribly confused when I reuse symbols for different purposes.

What I've discovered is that the students who have trouble with mathematical notation and reasoning got derailed when a teacher, in an early grade, said "let x be the unknown". That is a phrase that never comes up in other contexts, and I think it throws them off track. Many find it difficult to get back on-track later, so they memorize and sleep-walk their way through other mathematics classes until the system no longer insists that they take them. A shame, really.

manvillej · a year ago

I found this little pocket mathematics notation book when I first studying undergrad in this used book store in Boston. it literally carried me through Calc, Linalg, stats, dynamic programming, stochastic processes, game theory, economics, etc.

I ended up copying it by hand along with every exam and test notes over my entire degree into one little moleskine notebook. its a god send any time I have to remember how to do something or learn something new.

manvillej commented on Words flagged in search of current NSF awards mastodon.social/@Lazarou/... · Posted by u/croes

j7ake · a year ago

RIP statisticians and Ml researchers who use the word “bias” in their work.

manvillej · a year ago

RIP Academia as a whole

manvillej commented on Natrium 'advanced nuclear' power plant wins Wyoming permit wyofile.com/natrium-advan... · Posted by u/chiffre01

pfdietz · a year ago

This is a fast reactor. That is, a reactor in which the neutrons, instead of being moderated down to thermal energies, remain at high energy.

The fission cross section for such energetic neutrons is much lower than for thermal neutrons. Therefore, there has to be a much greater density of fissionable material in the reactor core.

The lack of a moderator also means rearrangement of the core in an accident is potentially much more dangerous. If the fuel itself rearranges to become more compact, say by melting and flowing, the reactivity could increase. This is not possible in (say) a light water reactor, where such a rearrangement would reduce reactivity.

The nightmare scenario for any fast reactor, warned about by Edward Teller in 1967, is a rearrangement that causes the core to become supercritical on prompt neutrons alone (that is, on only the neutrons released promptly at the moment of fission, not on those + the delayed neutrons emitted by some fission products as they decay). A fast prompt supercritical configuration could potentially explode with great violence, greater than Chernobyl. An atomic bomb is a prompt fast supercritical system.

I will want to see how the NRC does or does not license their design, a process that has just started. I will not be surprised if their approach ends up being unlicensable in the US because safety cannot be assured by analysis under accident conditions.

manvillej · a year ago

reddit had a nice list of the pros and cons: https://www.reddit.com/r/NuclearPower/comments/17k0wcc/natri...

I understand the risks around sodium, but the "passive natural circulation cooling" I don't understand. Is it more feasible with this design and why?

" Pros:

    high temperature means we can use process-heat which is a much more efficient use of heat.

    fast spectrum neutrons means we can burn importantly troublesome parts of nuclear waste.

    fast spectrum is also better for breeding new fuel, significantly increasing how much energy we can extract from uranium/thorium.

    passive natural circulation cooling is much more feasible.

Cons:

    fast spectrum is a little more complicated to control.

    fast reactors require high enrichment.

    inspection of the plant is very difficult with liquid metal.

    high temperature liquid metal doesn't play nicely with metal pipes.

    sodium burns in air and is explosive with water.

    we simply do not have nearly as much experience with sodium as we do water and that really cannot be understated.
"

manvillej commented on Fixing America's elevators is becoming a heavy lift axios.com/2025/01/05/elev... · Posted by u/ecliptik

massysett · a year ago

Stories like this make me a bit suspicious. It reads like some publicist - for the building owners maybe? or for elevator repair companies lobbying for something? - contacted the author or the website and said "I've got a great story for you, America is in an ELEVATOR CRISIS!" At first the writer yawned, but worked on this piece sporadically when there was nothing else to do, and several months later there was a slow news day, so might as well put this up.

I can understand saying there are some issues here, but "elevator crisis"? Yeah OK.

manvillej · a year ago

probably anecdotal, but I live in a new apartment building <2 years old. near CONSTANT elevator issues. 1-2 of the 3 elevators are out at a time. its been this way for a year.

can't wait for my lease to end.

manvillej commented on Slow deployment causes meetings (2015) tidyfirst.substack.com/p/... · Posted by u/fagnerbrack

sourceless · a year ago

I think unfortunately the conclusion here is a bit backwards; de-risking deployments by improving testing and organisational properties is important, but is not the only approach that works.

The author notes that there appears to be a fixed number of changes per deployment and that it is hard to increase - I think the 'Reversie Thinkie' here (as the author puts it) is actually to decrease the number of changes per deployment.

The reason those meetings exist is because of risk! The more changes in a deployment, the higher the risk that one of them is going to introduce a bug or operational issue. By deploying small changes often, you get deliver value much sooner and fail smaller.

Combine this with techniques such as canarying and gradual rollout, and you enter a world where deployments are no longer flipping a switch and either breaking or not breaking - you get to turn outages into degradations.

This approach is corroborated by the DORA research[0], and covered well in Accelerate[1]. It also features centrally in The Phoenix Project[2] and its spiritual ancestor, The Goal[3].

[0] https://dora.dev/

[1] https://www.amazon.co.uk/Accelerate-Software-Performing-Tech...

[2] https://www.amazon.co.uk/Phoenix-Project-Helping-Business-An...

[3] https://www.amazon.co.uk/Goal-Process-Ongoing-Improvement/dp...

manvillej · a year ago

this isn't even a software things. Its any production process. The greater amount of work in progress items, the longer the work in progress items, the greater risk, the greater amount of work. Shrink the batch, shorten the release window window.

It infuriates me that software engineering has had to rediscover these facts when the Toyota production system was developed between 1948-1975 and knew all these things 50 years ago.

manvillej commented on Spotify has shut down several API endpoints developer.spotify.com/blo... · Posted by u/leecoursey

Aurornis · a year ago

> So as long as they're winning, every corp is going to either shut down APIs or absurdly gouge prices. This is the new internet that we've voted for with money and attention.

I think you’re missing the real cause of this shift: These free APIs existed during the investment-fueled growth phase, then disappeared when they started switching into the real business mode.

We had an unusually long period of time where companies could play the startup game of spending money and headcount on things that didn’t generate much or any revenue. Free APIs were an artifact of that. The disappearance of the Twitter and Reddit APIs coincides with them shifting toward profitability.

You don’t have to “vote for” anything for this to happen. When it stops being easy to run companies at a loss year over year, the parts of the company that aren’t generating more revenue than they cost either get price increases or dropped entirely.

I’ve been at a startup-like company going through this change. It was sad, though not at all surprising, when management started taking inventory of everything people were working on and cross referencing it with how much that was generating in revenue. There were a few moments of internal revelation when someone realized that entire teams of expensive engineers had been working on features and products that either very few people used or that were very complex but generated no revenue. It doesn’t make business sense.

The abuse landscape has also changed dramatically. In the early days, free APIs were rarely used features by a few power users. Now, any free API is guaranteed to be abused by some growth hacking startup who wants to vacuum up all of your data and use it for SEO spam, AI training, or other purposes.

manvillej · a year ago

This is a standard technology company strategy. Isolate your customers, remove their options, markup the price.

manvillej commented on Denmark will plant 1B trees and convert 10% of farmland into forest apnews.com/article/denmar... · Posted by u/geox

mmooss · a year ago

Currently the public subsidizes the agriculture industry by paying for the consequences of the industry's carbon emissions. Also, that subsidy distorts industry choices in favor of carbon.

The industry might be accustomed to profiting from the subsidy, but that doesn't make them entitled to it! And certainly the industry has had plenty of time to anticipate and adjust to the problems of carbon emissions.

manvillej · a year ago

Governments pay to keep food at the cheapest point possible to ensure stability. a fed population doesn't kill their governments. Agriculture is not a regular industry; its a national security issue

Farming is not a profitable endeavor. There would be a lot less financial advisors in the world otherwise. A carbon tax will either drive up prices or reduce suppliers, increasing prices. Reducing farmland will require more efficient methods which will also drive up prices

The result will be the public pays more for food, not the agriculture industry makes any more or less money. It will require more imports which will come from countries with less regulation and more exploitable resources.

We've seen the story of disruptions to the food supply play out before. The reality is this is a more dangerous gamble than most people realize.

manvillej commented on Denmark will plant 1B trees and convert 10% of farmland into forest apnews.com/article/denmar... · Posted by u/geox

benmanns · a year ago

I think we should start doing more taxes combined with subsidies. Give everyone a $1/t carbon tax. Give everyone a ~$1/t farming subsidy based on current carbon production. Nobody loses, but everyone is incentivized to decrease carbon production and the faster ones profit more. Phase out the subsidy over X years if you like.

Otherwise, you’re right. We’re upsetting the balance of a very complex, very important system and causing a regressive tax in the form of price increases.

manvillej · a year ago

a combined tax and subsidy to try to drive farmers into more sustainable practices in a fiscally neutral way isn't a bad idea, but I think it is just a very risky and necessary roll of the dice.

I think inevitably, there will be price increases. The questions is just how bad and how many farms survive the transition.

manvillej commented on Denmark will plant 1B trees and convert 10% of farmland into forest apnews.com/article/denmar... · Posted by u/geox

JacobJeppesen · a year ago

I've seen a bit of confusion regarding this. First, it's 10% of Denmark's total land area, which is roughly equivalent to 15% of farmland area. Second, the conversion of farmland area into nature and forests is mainly for improving water quality, as excess nitrogen from agriculture has essentially killed the rivers and coastal waters through oxygen depletion from algae.

Regarding global warming and CO2, the area conversion of peatlands will help, but the major change here is the introduction of a carbon tax for the entire agricultural industry. And to end confusion regarding other emissions than CO2, it's actually a CO2-equivalent (CO2e) tax, which includes a range of other gasses. E.g., 1kg of methane is 25kg CO2e.

If you'd like to read more, see the two PDF documents below, which are the main official documents. They're in Danish, but upload them to Claude or ChatGPT, and you'll have a much better source of information if you'd like to know more about the specifics and how the actual implementation is planned.

[1] https://www.regeringen.dk/media/13261/aftale-om-et-groent-da...

[2] https://mgtp.dk/media/iinpdy3w/aftale_om_implementering_af_e...

manvillej · a year ago

I am very conflicted on a carbon tax for the agriculture industry. It is going to sidle a cost to an industry of razor thin margins. The transition from regenerative agriculture is expensive & rising food costs has a destabilizing effect.

There need to be changes, but I am not convinced that this will have the desired effects. Its quite possible this leads to a net conversion of farmland to residential or commercial property rather than nature.