Do you miss the old Quora answers of yore? I'm trying out a subscriber-only newsletter where I answer questions: askyishan.com/ Secrets to tech, AI, climate, social platforms, and more!

The Amazon rainforest generates its own rain. This is not a metaphor. Trees in the Amazon collectively transpire approximately 20 billion tonnes of water vapor per day from their leaves into the atmosphere, the largest non-oceanic source of water vapor on Earth. This moisture rises, forms clouds, moves on prevailing winds, and falls again as rain, often hundreds of kilometers from where it evaporated. Researchers studying this process call them the "flying rivers" of the Amazon: atmospheric flows of moisture driven not by ocean evaporation but by trees. Studies have estimated that approximately 50 percent of all rainfall in the Amazon basin originates from water previously transpired by the forest rather than from oceanic sources. The forest is not simply receiving rain. It is continuously recycling moisture to keep itself alive. The implications for deforestation are not intuitive. Clearing a section of Amazon forest does not simply remove trees. It removes transpiration input from the water cycle in that region. Less transpiration means less moisture entering the atmosphere, which means less rainfall, which means the surviving forest around the cleared area becomes drier, which makes it more vulnerable to fire and drought. A healthy forest creates the conditions for its own persistence. A degraded forest degrades the conditions of the forest around it. The flying river system also exports moisture far beyond the Amazon basin itself. Atmospheric moisture from Amazonian trees has been traced to rainfall in southeastern Brazil's agricultural regions, one of the continent's most productive farming areas. That agriculture is partly irrigated by transpiration from a forest it has no direct economic relationship with and no formal obligation to protect. #nature #science #forestfacts #conservation

The only country that has had a sane public policy reaction to rising home prices in my lifetime has been China. (Japan also has the right attitude about housing as a [non-]asset.) Being happy about house prices going up is like being happy about taxes going up.

Being happy that the housing market is going up is like being happy that taxes are going up.

Appropriate for this great day Going it’s own way since 1776

The manufacturing process for producing >200 million sterile screwworm flies a week can be summarized as creating a “76,000-square-foot artificial wound.” This is grotesquely fascinating:

There is a eucalyptus tree whose bark, at any given moment, is simultaneously vivid green, cerulean blue, deep purple, bright orange, and dark brown. Photographs of it are routinely assumed to be digitally altered. They are not. Eucalyptus deglupta, the rainbow eucalyptus, is native to the Philippines, Papua New Guinea, and eastern Indonesia. It is unusual among eucalypts in several respects. Most eucalyptus species are adapted to dry Australian conditions. This one grows in tropical rainforest. It is the only eucalypt with a native range that extends into the Northern Hemisphere. The mechanism of its colors is not pigment. The tree is not producing them deliberately. What happens: the outer bark is shed in irregular strips throughout the year, exposing fresh inner bark beneath. That inner bark is green because it contains chlorophyll. The rainbow eucalyptus photosynthesize through their bark. As the newly exposed bark ages, tannins accumulate as the tissue oxidizes. Different tannins produce different colors at different stages: bright green fades to blue, then purple, then orange, then reddish brown, until the outermost layer is ready to peel again. Because different portions of the trunk shed at different times, the trunk at any given moment is a mosaic of bark sections at different stages of oxidation. The result is a continuous abstract painting applied by the tree's own chemistry. The tree grows to between 60 and 78 meters in its native range, with a trunk diameter up to 2.4 meters. Its primary commercial application is the production of white pulp paper, which has approximately the same relationship to the tree's appearance as using Michelangelo's marble for paving stones. #exotictrees #forestfacts #nature #science

People think China doesn’t regulate its factories. It does and they all hate it. How do you think they turned their skies from black to blue? In 2016 they told one of our suppliers that they had to replace their coal boiler. They said “all your orders are delayed for 3 months” I said “cancel them”. They said “never mind. Well deliver on time” What did they do? They switched their work hours from during the day to the night and pumped black soot into the night sky where it couldn’t be seen by the government. Simultaneously they changed to a natural gas boiler. Thinking that China has world beating manufacturing because of cheap labor and lack of regulations like OSHA is cope. China goes hard.

BREAKING: FAA officially announced the rulemaking to legalize supersonic flight, including the Boomless Cruise ("Mach cutoff") approach we demonstrated on XB-1. This is a major step toward the supersonic renaissance.

imagine how fucked up it would be if one of your legs were an inch shorter than the other bc your scoliosis is so bad turns out usain bolt has this problem USAIN BOLT everyone with chronic pain issues downstream of odd mechanical problems needs to hear this

One thing that makes deep frying hard at home is that if you don’t use a huge amount of oil, the oil temp drops as soon as you put food in, making for a worse fry. @ImpulseLabs cooktop dynamically adjusts the burner output to maintain a set temp, overcoming this problem!

My dad gave me a piece of advice that has served me well: never make a comment about, or a play on someone's name. You will never impress them. You will only sink in their esteem. I met an old guy named John Lennon once, shook his hand and said "good to meet you Mr. Lennon." You could see the respect and joy at not hearing yet another damned comment about his name. Thanks dad.

Wow this was a great summary

A big problem with research studies on AI models is that given how long the peer review process is, the results are always out-of-date by the time the paper is published. This time, we have something better! The typical reaction to research results like this roughly goes "You're just testing on old models. Today's models are way better and surely can do it now!" But the best solution is for these papers to also open-source all of their testing framework so that upon publication, others can reproduce their results, as well as run it on the newest models of the day - and into the future. After all, "this is the worst they'll ever be" so what really matters is determining when they DO pass the threshold. As it turns out, the authors of this paper DID open-source their evaluation framework! Here: github.com/aiden-ygu/health-… So I figured... let's re-run the tests on the latest models! Summary of our results are here: github.com/ywong137/health-a… One drawback is that, unfortunately, the authors didn't (or weren't legally able to) open-source ALL the testing data, since apparently some of it is copyrighted by JAMA/NEJM etc. That's a separate problem with the medical research publishing industry for another time. However, we were able to reproduce the test on the public datasets they did include! First, we re-ran the same tests (as closely as we could) on the old models the paper claimed to use, in order to establish a baseline and determine how much "drift" there would be. (Answer: not too much) Then we ran those tests on the newest frontier models we could find. The results are: the most capable models today (GPT-5.5 Pro) did outperform the best models from before (79/100 vs 69/100), but did not improve enough to be considered sufficient for reliable medical use. In fact, the paper's criterion for "fit for reliable medical use" is more stringent, requiring the models to be robust under perturbation and bad data, knowing when to say there's not enough information, give clinically valid reasoning rather than hallucinations, etc. Those sound pretty reasonable to me. I wasn't able to reproduce that kind of qualitative evaluation, but even on the basic pass/fail test using public datasets of interpreting radiology images, the newest models are better, but not yet quite good enough. Nevertheless, I would like to praise the paper's authors for at least open-sourcing what they could, enabling me to (fairly quickly) attempt to reproduce their results. This is definitely a step in the right direction! While my reproduction wasn't able to be comprehensive, it certainly gave me useful directional info and - perhaps more importantly - allowed me (a random dude on the internet) to directly reproduce the results in their paper and validate them. I would like to encourage ALL authors of research papers on AI models to do similar open-sourcing of their experimental frameworks!

Restrained ground testing begun. The speed at which we can identify and fix issues with both the prototype and our processes is just unreal. At least 10x if not 100x faster than how fast I was fixing issues on my own VTOL builds back in pre-agentic dev days.

Gotta have the iron in him

This is genuinely shocking, and says so much about our approach to China. I decided to check for independent reviews of the English version Xi Jinping's latest book, published a year ago, to see what people had to say about it since I hadn't read it myself. To my surprise, I couldn't find any: not a single thoughtful review about the book out there! Even on Amazon, check it for yourself (amazon.com/XI-JINPING-GOVERN…): the book has only 3 ratings, that's it. No matter where you stand on China, you’ve got to admit that’s pretty crazy: the sitting president of the world's rising superpower publishes a 700-page book explaining exactly what he's doing and why, and we don’t even care to look. If there ever was a fact that illustrates just how willfully ignorant we are about China, this is it. All the more because we then go spew the usual clichés around how secretive and impenetrable the Chinese system is: the book is on Amazon for $21 for crying out loud! Anyhow, this felt so wrong that I figured I'd fix it. I bought the book, read it attentively and wrote what I hope you'll agree is a thoughtful review of it. The book contains genuinely surprising passages, such as Xi writing that oversight of the Communist Party by "the judiciary, the public, and the media" was not just something the Party must “readily accept,” but something that he framed as historically decisive - an essential component to "escaping the historical cycle of rise and fall" that has doomed every dynasty in China's history. Other passage that I'm sure would surprise many: a common narrative out there is that China blames the West for the century of humiliation and is driven by revenge. Well, Xi explains that's not true at all: the century of humiliation was China's own mistake, originated in the Ming Dynasty's disastrous "policy of national seclusion" that "resulted in China missing out on the opportunities presented by the Industrial Revolution" and "led to China’s decline." All in all, the book is remarkably self-reflective and thoughtful. For instance Xi recognizes that his drive for “full and rigorous internal governance” - including to rid the Party of corruption - risked "instill[ing] fear and apprehension, or intimidate members into inaction.” He emphasizes the need for pragmatism in this regard, codified in a framework called the “Three Distinctions” that separates honest mistakes - made while experimenting, reforming, or operating without precedent - from deliberate violations committed for personal gain. And many other surprises still. I found it a genuinely fascinating read for anyone interested in how the Chinese system works and how Xi thinks - or anyone interested in governance, period, as so much of what he writes is pretty universally applicable. This is the link to my review of the book, an article I titled "The Book the West Refuses to Read": open.substack.com/pub/arnaud…

The CUDA moat has evaporated overnight. CUDA was necessary when humans wrote code. Now it isn’t. TPU and other non-Nvidia architectures are about to take off.

Incredible history of the 2nd Punic War presented by the Fred Rogers, newly released by his estate.

"“Who elected you and Sam Altman?” Cooper asked. “No one. Honestly, no one,” Amodei replied." Actually... I wonder who we'd get if we really DID have an election to decide who should call the shots on AI guardrails. (add your nominations below and I'll run a poll later on the top ones)

It strikes me that if you look at AI in terms of “what product is it selling?” and realize the answer is “intelligence” or “thinking” then you quickly realize that certain demographics (both inside and outside the US) will value that, and thus have motivation to adopt it, while others don’t.