P.S. You Should Know... | Issue #473

Record ride

my story 🚀

🚲 Our daughter wanted to challenge herself to new personal record for bike ride distance. After 6+ miles and many of hills, we rolled up to our house and celebrated!

fun facts 🙌

Interstate 19: America’s only metric highway. “There’s not many places in the U.S. where you get a little math problem while you’re driving.” Interstate 19 in Arizona is a 102-kilometer stretch where signs are in meters and kilometers, and locals keep fighting to keep it that way. ~ learn more

Say now Shibboleth. “Then said they unto him, Say now Shibboleth: and he said Sibboleth: for he could not frame to pronounce it right.” So they killed him. A shibboleth is a word or habit that marks you as an insider or outsider. ~ learn more

A wastewater plant that grows nature. “The largest bio-remediation facility in the world” is cleaning Riyadh’s wastewater while building habitat along Wadi Hanifa. Permaculture instructor Andrew Millison visits the site and treats it like a working ecosystem, not just infrastructure. ~ learn more

Part bank vault, part citadel. “They are part bank vault, part food store and part citadel.” In southern Morocco, these agadir (igoudar) were communal fortress granaries where families stored grain, jewelry, and documents behind thick walls and carved wooden locks. ~ learn more

tech, startups, internet ⚡

How to finance a data center buildout. “An innovation on the finance side” is a phrase you never want to hear. The ‘conduit debt financing’ allows companies to access debt markets at scale without showing debt on their balance sheets, by using an intermediary known as a conduit. ~ learn more

HyperAgents that rewrite their own upgrades. “A hyperagent combines the task agent and the meta agent into a single self-referential, modifiable program, such that the mechanism responsible for generating improvements is itself subject to modification.” The idea is simple: let the system change both how it solves tasks and how it decides what to change next, so improvements can compound across domains. ~ learn more

GODMOD3. I’ve written before about Pliny the Liberator, an AI security researcher and LLM jailbreaker extraordinaire. Here’s his latest gift to the public: no sign-ups / guardrails / filters, and totally open source. “the most liberated AI interface ever built! designed to push the limits of the post-training layer and lay bare the true capabilities of current models. simply enter a prompt, then sit back and relax! enjoy a game of Snake while a pre-liberated backend agent jailbreaks dozens of models, battle-royale style.” ~ learn more or try yourself

Why ATMs didn’t kill bank teller jobs, but the iPhone did. “ATMs did not reduce bank teller employment. But they miss the second half of the story, which is that another technology did. And that technology was the iPhone.” The piece argues the ATM mostly shifted teller work around, while smartphones and mobile banking made whole interactions disappear. ~ learn more

better doing 🎯

The science of personality change. “Brian Little says that in the service of important personal projects, we can actually shape-shift for a short period of time in order to achieve our goals.” Olga Khazan explains how you can act like the person you want to be, long enough for it to start feeling like you. ~ learn more

Linus’s Law applies to science, too. The creator of Linux changed software by publishing his code and letting the community find and fix bugs, rather than polish for a long time before releasing. The author argues this works for research too: release early, let lots of weirdly qualified strangers take a look, and you get angles no tightly managed team will find. ~ learn more

to your health ⚕

Not for human consumption. Amid the FDA’s efforts to regulate peptides, communities on platforms like Telegram are conducting their own lab testing and trials, often without clinical backing. Retatrutide, a new frontrunner in weight loss drugs, shows promise with “28.7% weight loss in Phase 3 trials,” yet the market for grey-market peptides like BPC-157 continues to blur lines between legitimate health intervention and regulatory overstep. ~ learn more

The nutrition wars will never be won. “The universality can be wrong, even when the experience is real.” A good frame for why nutrition debates keep looping: people find what works for their body, then mistake it for a rule everyone should follow. ~ learn more

retail therapy 💸

AI-generated ads win, as long as users don’t know. “Across studies, we find that genAI-created ads consistently outperform both human-and genAI-modified ads, increasing click-through rates by up to 19% in field settings.” Visual generative AI shows more promise in creating ads from scratch than merely enhancing human designs. But… “Finally, we find that disclosing AI involvement in ad generation significantly reduces advertising effectiveness by up to 31.5%, underscoring trade-offs relevant to evolving AI disclosure policies.” ~ learn more

under the microscope 🔬

A way to rejuvenate the immune system. Stimulating the liver to produce some of the signals of the thymus can reverse age-related declines in T-cell populations and enhance response to vaccination, which is evidence of boosted immune reaction. ~ learn more

How exercise can lower Alzheimer’s risk. “Now, closely examining cells from geriatric animals’ blood-brain barriers, the researchers noticed that a damaging protein, known as TNAP, proliferated on the surface of those cells in far greater numbers than on cells from young animals, making the barrier more porous. Old animals that exercised, though, had much less TNAP dotting their blood-brain barriers than sedentary mice.” ~ learn more

Fasting hype meets a meta-analysis. “Intermittent fasting just doesn’t seem to work for overweight or obese adults trying to lose weight,” said Luis Garegnani, after a Cochrane-backed review of 22 randomized trials found IF was no better than standard dietary advice for weight loss. The paper still leaves room for possible benefits beyond the scale, like metabolic health. ~ learn more

teaching the kids 👩‍🏫

Selection bias, the real teacher. “In the world of educational data, “too good to be true” usually means there is a hidden variable in how the data was collected or filtered.” Readers may remember that I’m bullish on Alpha School’s claims on student education outcomes. Of course there’s tons of selection bias. Luke Shepard digs into Alpha School’s glossy test score claims and keeps coming back to the denominator: who got counted, who got excluded, and who could even afford to be there. ~ learn more

thanks for reading!