Hacker News Reader

scytheon New solar desalination breakthrough makes fresh water without toxic brine

Solar desalination looks pretty good in terms of efficiency. The problem is that the solar energy must now be collected at the shoreline. This means that a lot of coastal real estate gets turned into a desalination plant. Alternatively, you transport the water, but pumping seawater requires corrosion and fouling resistant materials throughout the system.

scytheon All of human cooking compressed into 2 megabytes

Two major contributing factors I can think of:

- land meats were all but banned in Japan for centuries prior to Perry's ultimatum, encouraging the development of alternatives in flavor and nutrition like natto and katsuobushi

- geographically, Japan had less access to land crops (even wheat was not common!) and more access to fish and seaweed than Korea

scytheon Why is almost everyone right-handed? A new study connects it to bipedalism

Sometimes I think people downvote me because they're frustrated that I didn't engage further. After twenty years of Internet discussions, I'm a little burned out and I tend to fire and forget.

scytheon Why is almost everyone right-handed? A new study connects it to bipedalism

Situs inversus ("dextrocardia") is a rare disorder. What I postulated is a (very) small selective advantage leading to a neurological mechanism evolving over generations, not a direct line from the heart to handedness during development. Anyway, the effect would be very slight, and even if it did exist, it could have gone away later, but dexterity would have been baked in at that point (see also the ocular blind spot).

scytheon Why is almost everyone right-handed? A new study connects it to bipedalism

Here's my five minute lunchtime hypothesis: it's because the heart is on the left. As human behavior demanded increasing precision from the hands, being a little farther from the heartbeat was a slight advantage.

scytheon High-Entropy Alloy

Most high-entropy alloys contain expensive metals so the primary domain of interest has mostly been as a coating for other metals. Recently there has been some work on AlCrMnFeNi, which is the cheapest composition I've seen by far.

scytheon The main thing about P2P meth is that there's so much of it (2021)

The production case for a stronger stimulant is weaker. Heroin is a really complicated molecule. It is only made from a natural precursor. Meth can be made by two major pathways, and P2P can be made by at least four off the top of my head. It was the fentanyl equivalent for cocaine. For anything else, you balance the increased complexity of synthesis with any increase in potency.

scytheon Spain has become one of Europe’s cheapest power markets

There have been two hydroelectric power plant failures in the United States in the last fifty years, and one near miss. This is among hundreds of dams many of which have operated for more than a century.

A pumped-storage dam also doesn't increase the area subject to flooding. If the upper dam fails, it flows into the lower lake. This can potentially be a design consideration. It's not like a greenfield hydropower dam.

If you want to play the rare catastrophic risk card, battery fires can release highly toxic hydrogen fluoride. But the damage of climate change is far greater than the very small risk from either dams or batteries, which is preventable in both cases with proper maintenance and monitoring. I think the tail risk question is moot, honestly.

scytheon Spain has become one of Europe’s cheapest power markets

>On top of that battery prices have been plummeting too so that now Solar + battery is cheaper than other options like Nuclear and especially Gas.

I'm a little bit sad that pumped hydro doesn't get more attention in the discussion. It might be too late for it to matter, with improvements in battery prices and ongoing lithium discoveries. But that only underscores the fact that it should have been allowed to matter twenty years ago. Utilities have slow-walked solar all around the world because of concerns about the grid stability, which has been well within the reach of pumped hydropower to fix since many years ago. In fact major pumped hydropower projects were mostly carried out in the United States during the nuclear power optimism era.

It is a little destructive to construct pumped hydro reservoirs. But it generally isn't as damaging as a conventional hydroelectric dam. The reason lies in the source of the water. In a conventional dam, you need a lot of water flowing in from up high, so you dam a major river near its lower cataracts. This disrupts the migration of fish and animals along the river and impacts the whole ecosystem of the rather large drainage basin upstream, and disrupts the migration of fish. But when a closed-loop pumped storage reservoir is created above an existing lake, usually a much less important stream is selected. Its immediate valley is still inundated, but the area of effect is much less. It does tend to prolong the use of the existing dam, but we are already preserving basically all existing dams.

It might still be appropriate in some places where imports are less affordable like Latin America or it might appeal to protectionists in the West. In general, hydro is usually cheap.

scytheon The Disappearance of the Public Bench

Homelessness and visible homelessness need to be distinguished here. The large majority of homeless people are not the ones you notice on the streets. Most try to be discreet. Some have jobs. A person who lives in their car is considered homeless.

The best measure to reduce homelessness is to provide timely support for people who are being evicted from their homes before they lose their jobs (which they might still have) and before their mental health deteriorates. This is the point at which assistance is most effective. You have heard the saying, "an ounce of prevention is worth a pound of cure". Such programs have been applied to great effect in e.g. London.

The way to respond to people who have experienced chronic homelessness with complications is different and more difficult.

scytheon The Old Guard: Confronting America's Gerontocratic Crisis

>This is likely the worst issue humanity will be facing over the next 50 years, even more than climate change.

Tangent, I know, but the climate change horizon is very long, much longer than 50 years. For example, a common projection is that the sea level will rise by almost one meter by 2100. This is already an unpleasant forecast. But it will continue to rise: under a 2 C warming scenario, sea levels reach (median prediction) 2.7 meters above the 2000 levels in 2300, which would be catastrophic. 2300 may seem far away, but it will come.

The current estimate is that we need to eliminate emissions this century and we will thereafter still need to do mitigation and removal to undo the damage, or extant coastal settlements will be destroyed. It is a very long process. See e.g.:

https://www.nature.com/articles/nclimate1584

scytheon The Old Guard: Confronting America's Gerontocratic Crisis

>Venice was run by very old men. It was common for the Doge to be in their 80s. Meanwhile, many of their neighbors had kings who were very young, sometimes teenage boys.

But those kings were (legally) absolute monarchs, while Venice was (somewhat) a republic. This isn't a trivial distinction. The young kings of the various Carolignian successors also tended to inherit their titles when their fathers were killed, while Venice occupied a highly defensible geographic location (a swamp) which supported institutional continuity.

scytheon Colombia hosts talks on exiting fossil fuels as global energy crisis deepens

It's on Wikipedia, sorted backwards:

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

Venezuela is an unusual case because their economy has been a disaster for the last half decade. And I agree that the data aren't so straightforward.

scytheon Colombia hosts talks on exiting fossil fuels as global energy crisis deepens

Most of South America has worked like this for decades. Hydropower is king even in Venezuela. It's altruistic on their part, but it may have reduced their long-term economic growth. Viewed in terms of GDP per capita, South America is a laggard. But if you change the denominator and look at GDP per kWh (energy intensity) they are surprisingly close to the rich world.

There is a hidden upside to all this hydro: it could potentially be upgraded to pumped storage and support a massive expansion of solar and wind. However, no SA country has such a forward-looking energy policy.

scytheon Online age verification is the hill to die on

>But if someone is willing and able to pay

If someone is willing and able to pay, they have a source of money. If they aren't allowed to buy something, that control should be applied at the level where they get the money. If the child is using an adult's credit card, responsibility lies with the adult. If children need to have their own credit cards, the obvious point of control is the credit card itself.

But also, most porn is ad-supported, pirated or free. Directly paid content is a small fraction. So all of this is moot for porn.

scytheon Can you stop beans from making you gassy?

>Here I feel the need for an aside. Many, many people will tell you that the key to reducing bean gas is to eat more beans. Eating more beans, they argue, works because it allows our digestive systems, and the microbiome in them, to acclimate to the beans. Over time, they say, the gassiness will go down. This makes no sense to me. If these oligosaccharides are food for bacteria in our gut, common sense would say that feeding that bacteria more food would, if anything, do the opposite by supporting their population growth while giving them plenty of raw material to digest. It wasn't within the scope of this project to test (and, I suspect, disprove) this theory, but count me as highly doubtful. If anything, I have to imagine that eating more beans more often just makes people more used to being gassy, and that, in turn, makes them notice it less. (Their significant others might have a very different take…)

I agree with this in principle but have to point out a few flaws in practice.

First, the immediate product of fermentation is not methane, despite what your high school biology teacher told you. It's hydrogen. In fact, bacteria do not produce methane at all! Only archaea are capable of methanogenesis. This is a rather surprising fact nobody mentioned in school:

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

>Organisms capable of producing methane for energy conservation have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with anaerobic bacteria.

So there is some room for error here. When methanogenesis occurs, the volume of gas is reduced by 80%:

4 H2 + CO2 >> CH4 + 2 H2O (l)

But I have never seen any evidence that the amount of archaea or the extent of methanogenesis in the digestive tract varies with diet. However, it does change under certain circumstances, and more methane in enteric gas is generally correlated with less hydrogen:

https://www.jstage.jst.go.jp/article/bmfh/45/1/45_2025-044/_...

>However, methane gas production was not changed by dietary intake, suggesting that intervention with prebiotics may be necessary.

https://iopscience.iop.org/article/10.1088/1752-7155/7/2/024...

>Usually patients produce either hydrogen or methane, and only rarely there are significant co-producers, as typically the methane is produced at the expense of hydrogen by microbial conversion of carbon dioxide. Various studies show that methanogens occur in about a third of all adult humans

(The second study is less optimistic than I am about methanogens reducing intestinal discomfort.)

But there is another thing that can change the amount of noticeable farting: unnoticeable farting. The digestive tract has its own nervous subsystem which reacts to stimuli and processes information. It's plausible that if you produce a lot of gas for a long time, your digestive tract learns to let it out gently. This may reduce irritation of the epithelium.

scytheon Ping-pong robot beats top-level human players

go fmt

scytheon AI Resistance: some recent anti-AI stuff that’s worth discussing

>It's a very comparable game of cat and mouse to spam email filtering. People also tried to claim that spam was over because for a time companies like Google cared enough to invest a lot in preventing as much as possible from getting through. If you've noticed in recent years the motivation to keep up that level of filtering has greatly diminished.

https://en.wikipedia.org/wiki/Lotka%E2%80%93Volterra_equatio...

scytheon A Brief History of Fish Sauce

I have a bottle of Colatura di Alici in my fridge. It's great when I remember to use it. But it costs about ten times as much as a Southeast Asian fish sauce, which is a natural consequence of only being produced in one town in Italy.

scytheon The Bromine Chokepoint

I think you misunderstand. I'm not arguing that the US will face a shortfall. The data above show that the US imports less than 25% of its bromine, but are redacted to prevent the public knowing the real amount. Factories in America are unlikely to face shortfalls of bromine.

But unless we have an extra 250 million tonnes of production capacity sitting on the sidelines, which would probably mean more than doubling our total output, we're not going to make up the shortfall for anyone else. We're talking about the majority of (disclosed) global production going offline if Iran could manage it (though again it is not clear that they can or will). China will also probably be using everything that they produce. Europe and the rest of Asia will be left high and dry. It's a win for the US strategy of critical minerals resilience, in some sense, but it's still a problem.

scytheon The Bromine Chokepoint

The US production in your linked article is listed as "W". This is explained as "Withheld to avoid disclosing company proprietary data". But imports consistently exceed exports, so it appears that US production is not likely to make up a global shortfall.

scytheon The Bromine Chokepoint

The British blockade probably did more for the downfall of Mossadegh than the US influence on the Shah. Iran's economy was severely impacted by the blockade and this allowed the Shah to gain support within the Iranian government for a coup. The US decided to support a coup because it was feared that a collapse of the Iranian economy would open the door to communist revolutionaries, and the US was not prepared to go against Britain and try to stop the blockade. I have wondered, however, if the outcome of the Iran situation in 1953 affected Eisenhower's judgment about the Suez crisis in 1956.

By 1979 it was no longer possible to marshal public anger towards the UK whose empire had been completely dismantled. Meanwhile, the US continued to support the Shah's regime by selling weapons until 1979, and this was probably at least as important as the coup for the image of America as a public villain during the Islamic Revolution.

scytheon The Bromine Chokepoint

Bromine is unusually concentrated in the Dead Sea, representing 0.4% instead of 0.0065% in the oceans:

https://en.wikipedia.org/wiki/Bromine#Occurrence_and_product...

The largest producer outside the Dead Sea is China by far, and the only other significant producer is Japan (!) which produces a paltry ~10% of worldwide output. It's possible to produce bromine from other places but you'd basically be starting from zero on the infrastructure involved. The short-term risks are real.

https://www.reportlinker.com/dataset/6b01d1a976f7ec9db71e35b...

However, it may be hard for Iran to disrupt bromine production. They may also not think about it.

EDIT: According to other links in this thread the US produces a significant but undisclosed (?!) quantity of bromine, practically all of which is consumed domestically. So it was probably missing from my data. Not great for other bromine users.

scytheon Why Japan has such good railways

>Do you see, or experience, a lot of contention for nighttime parking?

In the Hudson Waterfront of New Jersey, yes.

scytheon Why Japan has such good railways

>the same government, mysteriously, has no problem building a vast network of roads reaching everywhere and spanning the whole country.

Our road-building has slowed dramatically since the 1980s. The Interstate Highway network would be much more expensive and slow to build today.

>If the US government neglects a section of highway until a city becomes unreachable by roads, there will be riots.

Consider John's Island, South Carolina. The highway that was supposed to go there has been delayed for 33 years. Access to the island/town is through two two-lane roads that get backed up to a standstill every night. There's a running "joke" about how everyone is going to die if there's a major hurricane.

scytheon Helium is hard to replace

>The vast majority of MRI machines used today use superconducting magnets made from niobium-titanium (NbTi), which becomes superconducting at 9.2 degrees above absolute zero. This is well below the boiling point of any other coolant, making liquid helium the only practical option for cooling the magnets.

Well, this is part of it. The other issue is that the superconducting phase diagram has two limits: the transition temperature Tc and the upper critical magnetic field Hc. The magnetic field limit is generally highest at absolute zero and drops steeply with temperature. Even for the superconductors with Tc as high as 120 K the Hc at 20 K will be much less than the Hc at 4 K. So in order to make powerful superconducting magnets you need helium regardless of what superconductor you use, since nothing has broken this pattern.

scytheon Iran demands Bitcoin fees for ships passing Hormuz during ceasefire

Pakistan, the mediator of the agreement, declared that a ceasefire in Lebanon was part of the agreement when the agreement was announced:

https://www.reuters.com/world/asia-pacific/what-us-iran-isra...

>Pakistani Prime Minister Shehbaz Sharif announced the ceasefire between Iran and the United States on X, saying the two sides agreed to an immediate ceasefire everywhere, including Lebanon, where Israel launched strikes.

This suggests that either the Americans are lying or they did not read the agreement carefully before signing. Either way I don't think it's a good look for the United States.

The US has plenty of ability to force Israel to stop its invasion of Lebanon and it has done similar things twice before by economic means. All parties to the agreement are aware of this.

scytheon US and Iran agree to provisional ceasefire

>Calling Iranians who are against their current government “morally compromised” is real reprehensible for someone sitting in an armchair.

What I said was that anyone who wants their country to meet the fate of other countries the US has attempted to regime change is morally compromised. Simply hoping that the Islamic regime will go away is completely rational. Knowing that it will definitely fail and wanting to try it anyway is insanity.

And the diaspora fools cheering for more bombs and destruction are also in armchairs. They have no sympathy from me.

>Hoping foreign power can help overthrow the domestic lord is nothing new. That’s literally how the U.S. gained its independence with French military assistance.

Not regime change, a rebellion.

>And to your point, US interventions saved South Korea, Kuwait, Grenada, Bosnia, in addition to Panama.

South Korea was a response to invasion, Kuwait was a response to invasion, Grenada was a coup (response to a coup — edge case because the end state was much easier to define and also the country is minuscule), Bosnia was a rebellion. None of these are regime change.

>Kurds in Iraq can attest to this.

Also a rebellion. You might want to recheck the criteria.

>We don’t know how Iraq and Venezuela will turn out in the current timeline either.

23 years of civil war is too many. You can't just say "well eventually it worked out", that could justify anything. Other dictatorships have ended faster without violence. Venezuela was not a real regime change war because a deal was made with the VP before the invasion and also the Bolivarians are still in power.

scytheon US and Iran agree to provisional ceasefire

> There are news reports of Iranian expats and opponents within Iranian who are disappointed with the ceasefire. They wanted trump to go further and destroy the regime.

Most of them realized their mistake:

https://www.economist.com/middle-east-and-africa/2026/04/01/...

Iranians hoping that war and death will save them are chasing a gruesome mirage. The US has successfully liberated exactly one country by regime change since 1945: Panama in 1989. Every other intervention has either supported a rebellion (secession) instead of a revolution, or it has ended in failure (Afghanistan, Vietnam, Somalia) or a prolonged civil war (Iraq, Libya, Yemen). Anyone hoping for such a fate to befall their own country is morally compromised.

scytheon US and Iran agree to provisional ceasefire

JCPoA compliance was verified by the US and the IAEA regularly until the agreement was suspended by Donald Trump in 2018.