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Ask HN: Teach me something new

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Re: Ask HN: Teach me something new

#481

Post by ticklemyelmo »

idrios wrote: post #119

In drug development, a lot of the engineering goes into making sure the pharmaceutical compound -- having been developed -- actually reaches the target area of the body. If the compound is a relatively large particle that needs to get into the blood stream, a nasal spray might result in the compound being deposited at the bottom of a person's lungs without ever getting absorbed. If stomach acids break the chemical do…

When I was researching my kid's ADHD medicine I was fascinated to learn about its osmotic release delivery system (https://en.wikipedia.org/wiki/Osmotic-controlled_release_ora...).

What looks like a simple pill is actually a tiny machine that delivers the medicine at a precisely controlled rate over a period of hours.

Re: Ask HN: Teach me something new

#482

Post by ajot »

ajb wrote: post #229

In statistics, the mean and median are both averages, but are technically quite different. The mean is the sum of all items divided by the number of them, while the median is the middle item in the sorted list. When they are different, this can have strange effects. For example, when estimating engineering tasks, the mean error is often positive while the median is often negative. This is why your manager believes th…

> In statistics, the mean and median are both averages, but are technically quite different. The mean is the sum of all items divided by the number of them, while the median is the middle item in the sorted list.

There was an article posted here, one or two years ago, that explained how mean and median are very similar, as they are the values that minimize residuals or the squared of residuals.

I'm sorry I can't find it right now, I hope some other user knows which article I'm talking about and can link it down here, because it is, in my opinion, an excelent read.

Re: Ask HN: Teach me something new

#483

Post by thematrixturtle »

tomrod wrote: post #433

Filipino and Polynesian languages come from the same linguistic branch, and their numbers are similar for most and the same for some.

It's over 11,000 km from Malaysia to the Cook Islands, yet the number 5 is lima in Malay and rima in Cook Islands Maori.

Re: Ask HN: Teach me something new

#484

Post by leemailll »

ajb wrote: post #229

In statistics, the mean and median are both averages, but are technically quite different. The mean is the sum of all items divided by the number of them, while the median is the middle item in the sorted list. When they are different, this can have strange effects. For example, when estimating engineering tasks, the mean error is often positive while the median is often negative. This is why your manager believes th…

median could be average, but that depends on the probability distribution of your data

Re: Ask HN: Teach me something new

#485

Post by randlet »

mikelevins wrote: post #385
CGamesPlay wrote: post #219

Earlier quoted context omitted.

Interesting. I get these scotomas about every 6 months or so, usually lasting for 30 or so minutes. I was told they were called "ocular migraines", and a cursory glance over the internet doesn't seem to help me differentiate between the two, although I will say that [0] is a very accurate depiction of how it looks when it happens to me. I normally just take a break from whatever I'm doing and go for a walk. The first…

The image you linked is what I'm calling "flickering". My full-blown scintillating scotoma is much more vivid and fully-formed. In the incident I'm reporting, it was a 3D physical-looking structure of triangular prisms made of white light, with zebra stripes of utter blackness sweeping rapidly along them, surrounded by an aura that looked like a cross between the sun's corona and the aurora borealis. These links are…

Your first link is exactly what it looks like to me (except pulsing/shimmering). I can usually sense it before it starts then it starts as a small aberration and gradually grows to encompass almost my entire vision. Extremely unsettling the first time it happened.

Re: Ask HN: Teach me something new

#486

Post by spcebar »

The saying "blood is thicker than water" is from the Bible. The full quote is "the blood of the covenant is thicker than the water of the womb," which means the opposite of how "blood is thicker than water" is used.

Re: Ask HN: Teach me something new

#487

Post by aldebran »

dssagar93 wrote: post #342

I'm gonna throw some Hindu mythology- time travel here. Did you know that time-travel is a modern concept but in the Indian scriptures, which dates back to thousands of years already mentioned about it. It is a story about King Kakudmi, who sought a husband for his beautiful daughter, Revati. They both had travel to Lord Bhrama's(Creator of the universe) place which was apparently very far from our planet to seek adv…

If you got a kick out of that, it gets better!

There’s a publication called “Date Panchang” that gets a new version for every new Hindu year. The first few pages talk about time and how Brahma experiences time.

If you can read sanskrit/Marathi, it’s page 5 here: https://pdfcoffee.com/qdownload/date-panchang-2020-pdf-free....

It talks about how long Brahma’s life is and where I’m his life he is right now. Not sure how they calculated that but it’s pretty wild to think about.

Re: Ask HN: Teach me something new

#488

Post by travisjungroth »

cricalix wrote: post #378
Zircom wrote: post #196

Earlier quoted context omitted.

You haven't experienced a whole lifetime. Every moment up until the current [whatever the smallest unit of time really physically possible is] is just a memory of an experience. Subjectively from your perspective there's absolutely no difference between having actually experienced all that and merely having memories of having experienced all of it. You could materialize into existence for exactly one moment and belie…

Now that's an existential crisis right there. There's no way to determine if I've literally flashed into existence and am remembering this sentence, and am thinking of how to continue it, versus actually existing on the timescale of a human life. Urgh. Then again, does it matter? Probably not.

I came to the same realization at about 12 years old. The mechanics were different than the Boltzmann brain. I saw it as that there are only two things that define the current universe: matter and energy. How could I know the universe wasn’t _just_ created? Every atom of my house, every atom of my body, created or placed in just the spot it is now, with just the energy it has now. My memories from five minutes ago are exactly what a brain that looks like mine would “remember” from five minutes ago.

Looking back, this realization became a feeling and this feeling became the backdrop for much of my growth as a person. Sometimes I was filled with fear. Sometimes I would shed all responsibility because it didn’t feel real.

At the best times, it fills me with a profound sense of agency, balanced with responsibility. It’s like teleporting into someone else’s body. Some things you choose to play along with, taking care of “his” mother. Other things you abandon, changing direction in your life as you need, despite what anyone might say.

Re: Ask HN: Teach me something new

#489

Post by O_H_E »

eps wrote: post #287
helph67 wrote: post #36

Here's mine, the Pareto principle or the 80/20 rule. You will find that it applies in MANY ascpects of life and knowing it may give you an `edge'. https://en.wikipedia.org/wiki/Pareto_principle

Closely related - In theory, there's no difference between the theory and the practice. In practice, there is.

Oohh, that is good. Actually made me laugh

Re: Ask HN: Teach me something new

#490

Post by leemailll »

SemanticStrengh wrote: post #122

Very few people know the potent facts about the brain: * your neurons are not in your "brain" 90% of your neurons are not in what you generally denote by brain. They are in your cerebellum. The cerebellum has a distinct neural architecture, that difference is in fact clearly visible with the najed eye. A very poor simplistification would be to call it our GPU. * the spinal cord is huge and is structurally a contiguou…

I don't know where you get the idea brain does not include cerebellum. This is completely false
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