Hacker News Reader

dumahon Why the weak nuclear force is short range

They definitely wouldn’t work because we have strong evidence that relativity is a more accurate theory and significant evidence that either gravity does not obey an inverse square law or our estimation of the distribution or nature of dark matter is incorrect.

https://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gr...

dumahon An artist who trained rats to trade in foreign-exchange markets (2014)

FOREX volume is almost 10% of annual global GDP _per day_.

This trading is overwhelmingly unrelated to trade in goods or services, or the movement of wealth with much permanence.

dumahon Bankruptcy judge rejects sale of Infowars to The Onion

FTX creditors would like to have a word with you.

dumahon A simple way to scale pixel art games

We don’t need a statement of intent because we have historical records of their work process simultaneously using both TV and computer displays.

dumahon Engineers do not get to make startup mistakes when they build ledgers

The US Government formerly fixed gold prices by statute and prohibited US citizens from owning or trading gold anywhere around the world.

The idea such a system could function in todays world is strange to me.

dumahon GM Under CEO Mary Barra Is an Undeniably Soulless and Dishonest Company

Being undeniably soulless and dishonest is still major progress from powering anti-Semitic political campaigns, world war 2, and the Holocaust.

https://jweekly.com/2006/12/01/financing-of-racist-anti-semi...

https://www.washingtonpost.com/wp-srv/national/daily/nov98/n...

https://www.jewishvirtuallibrary.org/general-motors-and-the-...

dumahon Fly.io outage (restoration in progress)

I take your point but corrosion-resistant metals such as Aluminum, Titanium, Weathering Steel and Stainless Steel don’t avoid corrosion entirely but form a thin and extremely stable corrosion layer (under the right conditions).

dumahon Only buy a magnetic keyboard for gaming

Using Razer as an example, the full size keyboard is 6 inches wider than a 60%, and 3.5 inches larger than the 80%.

You said 2 inches but it’s actually half the width of a 13” laptop.

I can fit a compact keyboard and a trackpad in the size of a normal keyboard.

dumahon Spanish police arrest ex-fraud chief after €20M found in walls of his house

“I ask: in case I ever get my hands on millions in cash, what is my plan for using it?”

The question wasn’t how the Spanish Anti-Fraud chief would launder.

A number of high-profile acts in the US have had managers convicted for this in connection with drug trafficking and other organized crime.

It’s absolutely plausible.

I’m not sure why you think a cursory audit would reveal that a cash receipt was forged.

dumahon Christopher Columbus may have been Spanish and Jewish, documentary says

Some Protestants hold that Catholicism is not a sect of Christianity due to a number of beliefs, such as the different requirements for salvation.

I don’t know how common this belief is in the US but I personally have encountered a number of people that believe this.

dumahon Christopher Columbus may have been Spanish and Jewish, documentary says

Most Americans (62%) have European ancestry.

You are listing the most frequent origins of immigrants to America as of 2024.

I’m not sure how this is relevant to the prior discussion.

https://www.census.gov/library/stories/2023/09/2020-census-d...

dumahon Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

The joke is that Sol is a gravitationally confined thermonuclear reactor.

dumahon Legalizing sports gambling was a mistake

I don’t know exactly what the right regulation would look like to restrict this specific kind of activity, but I don’t have a problem, in principle, with such regulation.

dumahon An Intuitive Explanation of Black–Scholes

Black-Scholes assumes constant volatility and cannot compute option prices without a volatility input.

This volatility is backed out of nearby options prices, often using the formula for European options.

There isn’t any purely theoretical option price because an assumption depends on observed prices.

dumahon Some Automattic employees accept severance package offer

As of 11 months ago, Fidelity had marked down their stake by 71%.

As of now, it’s 80%.

Are you saying that your threshold for “serious” is more than a 71% loss of value?

These losses are squarely in the territory of those who are commonly labeled as “worst ceo’s of all time”.

dumahon Legalizing sports gambling was a mistake

Sports betting is a negative EV zero-sum game motivated by an addiction, for a significant fraction of the population.

Investment in equities is principally a non-zero-sum positive EV game motivated by rational expectations for preservation and growth of wealth.

The fact that some financial actors have very good sharpe ratios or dominate capture of trading profits on millisecond horizons isn’t a significant detriment to the larger good resulting from retail investment.

dumahon Show HN: Iceoryx2 – Fast IPC Library for Rust, C++, and C

https://github.com/apache/arrow/issues/34738

https://lists.apache.org/thread/lk277x3b9gjol42sjg27bst2ggm5...

dumahon Netflix's Key-Value Data Abstraction Layer

Netflix serves over 40,000 hours of video in more than 100 encodings. Source files are high quality and can reach terabytes per hour of bitrate. Source data must be retained for re-encoding. Encoding is adaptive to scene. The ETL can generate a quarter million tasks to process one source file.

I’m not saying YouTube’s problem isn’t much larger, but your assumptions are off by orders of magnitude. If you are curious about the workload there are many blog articles and stories here.

dumahon MicroPython on Flipper Zero

Emulating the rolling code protocol would desync your keys.

What ever device you’d want to use as a backup would need to capture information sent from the vehicle during the last unlock.

dumahon Sunamp's thermal battery uses a chemical found in salt-and-vinegar potato chips

Sodium Acetate is an interesting chemical - it’s also effective at improving the hydraulic properties of concrete.

https://scholar.google.com/scholar?hl=en&as_sdt=0%2C33&q=sod...

dumahon The guidance system and computer of the Minuteman III nuclear missile

The physical environment these weapons were designed for is extreme and only possible to simulate piecemeal.

Each stage needs to function in the presence of nearby nuclear detonations, resulting from both adversary and friendly weapons.

These detonations are expected to cause severe shock, thermal, radiation, and electromagnetic transients.

In the case of the most important targets, it is guaranteed that numerous detonations near the target, from ABM systems and friendly impacts, will occur, and these systems have been engineered and are expected to perform reliably under such conditions.

dumahon The Third Atomic Bomb

No, super-criticality occurs in a nuclear reactor when ever the neutron population is increasing.

You might be conflating that condition with prompt criticality.

dumahon The Third Atomic Bomb

In the case we are considering, it doesn’t, but it could with other materials.

Consider that the wavelength of the neutron is a function of its energy, and that the cross sections for interaction between nuclei and neutrons are strong and complex functions of energy.

If the cross section for the interaction of interest gets smaller with decreasing energy, then it would be the case that the neutrons mean free path length would increase as energy decreased.

dumahon Python extensions should be lazy

Cython implements a C api for accessing the underlying data structure.

Arrays implement the buffer interface so they can be used efficiently with tools like numpy.

dumahon Python extensions should be lazy

A performant table data structure with powerful and convenient syntax for interaction is one great feature Q has that Python lacks.

dumahon Python extensions should be lazy

3. The memoryview interface is often a good solution.

dumahon The future of kdb+?

You didn’t learn Q in two weeks to the extent that you are qualified to assert that someone who knows how to use a Python IDE is more productive than a quant dev with decades of experience.

I find it much more likely that you couldn’t understand their code and quit out of frustration.

If you were a highly skilled quant dev and this was a good seat, quitting after two weeks would have been a disaster to manage the next transition given the terms these contracts always have.

dumahon Engineering principles for building financial systems

Timezone, not the offset, should generally be stored.

Offsets rotate throughout the year.

If you store only the offset, you can’t necessarily apply a delta to the time and localize it to the origin locale.

dumahon Making my own wedding rings

On Naval deployments, it’s common for mechanics, who are planning on proposing or are engaged, to file nuts into pairs of wedding bands.

This can take weeks or months, depending on the material and method.

Since there are nuts available from peculiar corrosion-resistant alloys and superalloys, the product can be quite unique.

dumahon Pattern of brain damage is pervasive in Navy SEALs who died by suicide

Round parachutes are typically deployed with a static line and open very quickly, resulting in significantly higher acceleration.

Ram air parachutes can effectively open in a more gradual manner due to the cellular design.