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Cake day: July 4th, 2023

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  • It’s not that we don’t use mode, there are definitely times mode is used. It’s just that mean (and median as well) contain a lot more useful information about distributions that we often care about. For a normal distribution mean, median, and mode should all be identical. So why do we use mean? Because mathematically, the mean is what underpins the formula for the normal distribution, not median or mode, and when you’re talking about doing math with normal distributions mean is the thing to talk about (along with standard deviation).

    We use median a lot too, you probably just don’t hear it called median very often. The median is useful in non-normal distributions, and it defines the 50th percentile, so along with the 25%-ile and 75%-ile you’ve got your quartile distributions. We use these all the time to talk about grades in schools, or when we talk about home prices distributions in a given area, or salaries within a given field.

    We use mode too, again just by a different name most of the time. Any time you’ve asked “what’s the most common blank” you’re basically asking for a mode. When we talk about “average” income in a country, we’re usually actually talking about median or mode. Favorite animal? Answered as a mode.

    You have to use the right statistical tool for your question: unfortunately English doesn’t do a good job of conveying this without math jargon.


  • This is an alternative birth method called “lotus birth” or more formally “umbilical non-severance” in which babies are left tethered to the delivered placenta until their cord desiccates and detaches from their body on its own, usually in 3-10 days, while applying salt to the placenta to increase the speed at which it dries. It will eventually fall off, however, after its delivery the placenta is no longer being supplied with the oxygenated blood it needs to survive, and becomes necrotic (dead). This can act as an easy entry point for infectious organisms to enter the neonate, and can result in life-threatening infections. Neither the American College of Obstetrics or the American Academy of Pediatrics have explicit guidance statements as to whether this should be recommended against. AAP has published that there have been multiple case reports of severe infections with various bacteria secondary to this practice.

    This should not be confused/conflated with Delayed Cord Clamping, which is waiting 30-60 seconds after the baby’s delivery for some of the residual fetal blood in the placenta to be delivered to the baby’s circulation to prevent anemia. This has good evidence for benefit to the baby, is recommended by ACOG, and is basically standard of care in the US.

    Source: ACOG and AAP publications, also I’m a 4th year medical student that has completed OBGYN rotations






  • If I was guessing, in general, I think people who advocate for a pure meritocracy in the USA feel the world should be evaluated in more black and white, objective terms. The financial impact and analytic nature of STEM and finance make it much easier to stratify practitioners “objectively” in comparison to finding, for instance, the “best” photographer. I think there is also a subset of US culture that thinks that STEM is the only “real” academic group of fields worth pursuing, and knowledge in liberal arts is pointless -> not contributing to society -> not a meaningful part of the meritocracy. But I’m no expert.


  • As a general rule, yes. People who are able to better perform a task should be preferentially allocated towards those tasks. That being said, I think this should be a guiding rule, not a law upon which a society is built.

    For one, there should be some accounting for personal preference. No one should be forced to do something by society just because they’re adept at something. I think there is also space within the acceptable performance level of a society for initiatives to relax a meritocracy to some degree to help account for/make up for socioeconomic influences and historical/ongoing systemic discrimination. Meritocracy’s also have to make sure they avoid the application of standardized evaluations at a young age completely determining an individual’s future career prospects. Lastly, and I think this is one of common meritocracy retorhic’s biggest flaws, a person’s intrinsic value and overall value to society is not determined by their contributions to STEM fields and finance, which is where I think a lot of people who advocate for a more meritocracy-based society stand.





  • It depends on the half life of the element in question. The most comparable concrete thing we can compare this to with real numbers because we know it works is an RTG. RTGs are solid-state generators, but people could colloquially refer to them as “batteries” and not be terribly wrong. They take a quantity of a radioactive material and allow it to decay, using the heat given off to establish a thermal gradient which is then converted to electricity via thermocouples. Most of these are “fueled” with Pu-238 (at least the ones for spacecraft), which has a half life of 87.7 years. That means in 87.7 years, if you started with 4kg of Pu when you built it, you’d have only 2kg of Plutonium left. If the Pu decayed only into stable isotopes (it doesn’t) then your radioactive emissions/decay would also be exactly halved at this time. If the electrical system is perfectly efficient this would also halve the electrical power produced.

    I provide this all as background because to answer your question you have to know three key factors about the device to determine the lifetime of the battery. The half-life of the isotope used, the minimum electrical requirements of the device you’re powering, and the amount of radioactive material in the initial battery. The battery’s lifetime is determined by when decay will decrease the ongoing energy output below the minimum current and voltage requirements needed by the battery. The longer the half life of the isotope, the slower this decrease is and the less initial overpowering that is required.

    Ex. If you use an isotope with a 12.5 year half life for a “50-year” battery, you would need to start with 8 times the material needed for your minimum power output requirements. If you use an isotope with a 200 year half life, you only need 19% more starting mass than you minimum requirement. The first battery will produce 8x the power at the very beginning, while the second will only produce 18% more.





  • A lot of the really prestigious medical schools/residency programs have a reputation for a toxic culture, and this means by and large they attract a larger share of toxic applicants. Their programs are really focused not on training great bedside clinicians, but on training people who will attempt to change fields through research and public policy. Unfortunately, the toxic nature of these programs, and their immense emphasis on publishable output and reputation, likely attract a larger fraction of narcissists with the skills necessary to mask their inappropriate behaviors when needed in comparison to other programs. That is not to say that all Harvard trained physicians are horrible people, I’m sure the vast majority of them are fantastic, but I would be money that Harvard attracts a greater fraction of the kookes than your average midtier medical school.