Massive 'ocean' discovered towards Earth's core - <AUTHOR> http://www.newscientist.com/article/dn25723-massive-ocean-discovered-towards-earths-core.html <comment><USER2> This seems to be a confirmation of a study that what was published in March: [http://www.dailymail.co.uk/sciencetech/article-2579584/The-v...](http://www.dailymail.co.uk/sciencetech/article-2579584/The- vast-reservoir-hidden-Earths-crust-holds-water-ALL-oceans.html)

<comment><USER3> Woo...Daily Mail being used as a news source I'd avoid that comic in future, it's the UK equivalent of the National Enquirer.

<comment><USER4> Sources can be a joke until they happen to be correct. Sometimes it's worth considering the claim despite the source.

</comment></comment></comment><comment><USER5> I know that truth can be stranger than fiction, but am I the only one a little hesitant to believe that underneath the U.S. alone is a reservoir that is _three times_ the volume of _all the oceans combined_?

EDIT: I didn't mean to imply that this exists only under the U.S. and nowhere else. I meant to imply "so far, the existence of this reservoir has only only been confirmed under the U.S.; the rest of the world is unknown at this point".

<comment><USER6> 3D space is infinitely larger than 2D space :)

The deepest point in earth's oceans is 12 km or so, and the average is ~4km. Now, imagine this discovered reservoir is 400 km "deep". It means it will have 3x the volume of all oceans even if its surface area is 30 times smaller.

<comment><USER7> From the article:

      Sure enough, they found signs of wet ringwoodite in
      the transition zone 700 kilometres down, which
      divides the upper and lower regions of the mantle.

From wikipedia:

      The transition zone is part of the Earth's mantle, and
      is located between the lower mantle and the upper
      mantle, between a depth of 410 and 660 km.

So, if our planet is roughly 12,000 km in diameter (6,000 km to the center), then this region of depth represents a 100-200 km thick shell where pockets of water may exist. But let's max it out, and try to find the volume ((4/3) * (pi r^3)) using very rough, round numbers to get an upper ceiling.

Hypothetically, if it _were_ a continuous shell of pure, fresh water encapsulating the entire inner mantle and core, and if it happened to be 200km thick, with an inner surface at 600 km deep (the shell's floor starts at a radius of 5,400 km) and an outer surface at 400 km deep (the shell's ceiling stops at a radius of 5,600 km), the intervening space could collect possibly a volume close to 76 billion liters of water.

Compare this to a hypothetical scenario, where our planet's rocky crust has a radius of 5,995 km, and is completely covered in one giant ocean of water 5 km deep (think Water World with Kevin Costner) for a total diameter of 12,000 km, this huge ubiquitous ocean would only contain 2 billion liters of water.

So, in a world of perfect spherical maximums, rounded to the nearest billions in liters, this subterranian zone could contain 38 times the water we currently observe on the surface of the earth.

<comment><USER8> You dropped some zeros. A billion liters is a cube 100 meters on a side, more like a drop than an ocean.

<comment><USER7> Wait, you're right. I think I dropped about maybe 4 zeroes off the exponential notation. Strike the "billion" and make it like 10^11th or 10^12th power. Either way, I think the ratios still work.

<comment><USER7> ...and oh yeah, by the way, my units were the wrong order of magnitude; should've been kiloliters (not just liters), on top of the exponential notation.

</comment></comment></comment></comment></comment></comment><comment><USER9> Excerpt:

 _By measuring the speed of the waves at different depths, the team could figure out which types of rocks the waves were passing through. The water layer revealed itself because the waves slowed down, as it takes them longer to get through soggy rock than dry rock.

Jacobsen worked out in advance what would happen to the waves if water- containing ringwoodite was present. He grew ringwoodite in his lab, and exposed samples of it to massive pressures and temperatures matching those at 700 kilometres down._

To me, as someone who knows not that much about all this, that sounds like it could well be hooey. It could be voodoo. It could be a Tall Tale.

Can anyone explain to me (like I am 5 years old) how such things get vetted or taken seriously or whatever?

No, I am not trolling.

Thanks.

<comment><USER10> It's a fair question.

Observing how waves travel through planetary bodies is one of the most useful methods for looking into the interior of these objects. On a fundamental level, it's an advanced version of knocking against a large metal silo to determine if it's empty or full.

However, detailed findings can be tricky sometimes. In this case, the geologist calculated beforehand what the frequency absorption fingerprint of "rock containing water" would be, and then he found a matching signature in the measurements he took.

Indeed there are several things that could have gone wrong: the signature of the substance might be different than previously assumed, or the seismic measurements themselves could be faulty.

Over time we'll get more measurement opportunities and we'll refine our models as more scientists will work on this. There might be more evidence from other sources available if we know how to look for it, too. So the confidence level in this finding will be modified in the future.

Right now it's just an intriguing but singular result that deserves further study.

<comment><USER9> _Right now it 's just an intriguing but singular result that deserves further study._

See, I guess that is my issue here: The article talks like we KNOW this for sure, not like "preliminary results suggest..." when no one has sampled anything that deep to verify it etc.

Thank you.

</comment></comment></comment><comment><USER11> Uh oh.

[http://en.wikipedia.org/wiki/Flood_(Baxter_novel)](http://en.wikipedia.org/wiki/Flood_\(Baxter_novel\))

<comment><USER12> I remember in the 90's there was a conspiracy theory going around that the 'global elites' had created a massive submarine base - in the middle of the Amazon jungle, i.e. hundreds of miles from the oceans - specifically to use as a survival plan in case of a massive flood. There was even a site dedicated to the 'discovery' of photo's of the massive submarine, taken from a light airplane which crashed .. the camera was found and later the pictures were made available.

I wonder if the author of "Flood" had heard of this theory and incorporated it into his book. Try as I might I can't find _any_ details about this jungle submarine base any more - seems its been wiped off the 'net.

Another thing I thought of is the Cataclysm as described by Szukalski, that weirdo. He posited that every 64,000 years, the Earth undergoes a massive upheaval due to "Gravity heat" which busts open the Earths' core and releases massive amounts of water from within. Now that there is actual scientific evidence of this whacky theory, I'm starting to get a bit more interested in finding that jungle submarine base .. ;)

<comment><USER13> Well, there are free and almost free satelite photos of the entire Amazon jungle available. Thus, nothing is stopping you.

<comment><USER11> A 100 foot high canopy means concealing something in the Amazon would be pretty straightforward.

<comment><USER13> One can easily hide something that has less than 20 or so meters hight (because trees rarely get over that height), and smaller than a few trees in area. If the thing you want to hide is bigger than that, you'll have better luck in a cave, or disguising it as a rock and placing it in the middle of a desert.

</comment></comment></comment></comment></comment><comment><USER14> Just hypothetically.

If the story of the great flood (Holy Bible) is real - could it be that this is where all of the water has gone? Could this water some time in the future "rise up" once more and create a second worldwide flood?

<comment><USER15> If by rise up once more you mean it rose up the first time, then no--the bible claims it just rained a bunch of days.

<comment><USER16> That's false.

> 11 In the six hundredth year of Noah's life, on the seventeenth day of the > second month—on that day all the springs of the great deep burst forth, and > the floodgates of the heavens were opened. 12 And rain fell on the earth > forty days and forty nights.

[http://www.biblegateway.com/passage/?search=Genesis%207&vers...](http://www.biblegateway.com/passage/?search=Genesis%207&version=NIV)

<comment><USER17> That's really ambiguous. I read it to mean deep springs in heaven opened and it rained from them.

<comment><USER18> It isn't ambiguous under the commonly accepted scientific facts of the time, in that particular civilization.

They believed that they were on a flat earth under a dome that separated the atmosphere from huge amounts of water above (hence the blue color of the sky) and below (hence the oceans). They believed that the dome leaked sometimes, causing rain. They believed that the flat earth leaked too, causing rivers.

More information here: [http://en.wikipedia.org/wiki/Biblical_cosmology](http://en.wikipedia.org/wiki/Biblical_cosmology)

<comment><USER19> Ted Chiang played around with ancient Near East cosmology to great effect in his story "The Tower of Babylon"

[https://en.wikipedia.org/wiki/Tower_of_Babylon_(story)](https://en.wikipedia.org/wiki/Tower_of_Babylon_\(story\))

</comment></comment></comment></comment></comment></comment><comment><USER20> An ocean as imagined by Jules Verne in Journey to the Centre of the Earth. A splendid bit of early fantasy fiction. I recommend 'Lost' \- the chapter where the narrator gets separated from his Uncle in caverns 70 miles underground.

<comment><USER21> Except that it looks more like a huge rocky sponge.

</comment></comment><comment><USER22> Seems like a pretty nice place for a Great Old One to fhtagn.

<comment><USER23> For the lazy, it's "dream" or "dreaming" :)

       "Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn"

translates to:

       "In his house at R'lyeh, dead Cthulhu waits dreaming."

</comment></comment><comment><USER24> It would be so cool to get a sample of that water (assuming it does in fact exist) and see what type of life is in it (if any). It would be almost like seeing life from another planet.

<comment><USER25> > In the mantle, temperatures range between 500 to 900 °C (932 to 1,652 °F) at > the upper boundary with the crust; to over 4,000 °C (7,230 °F) at the > boundary with the core. [1]

Those would be some pretty extreme extremophiles!

> However, it is thought unlikely that microbes could survive at temperatures > above 150 °C, as the cohesion of DNA and other vital molecules begins to > break down at this point. [2]

Aww man! Though there are some pretty amazing extremophiles out there anyway!

[1] [http://en.wikipedia.org/wiki/Mantle_%28geology%29#Temperatur...](http://en.wikipedia.org/wiki/Mantle_%28geology%29#Temperature)

[2] [http://en.wikipedia.org/wiki/Hyperthermophile#History](http://en.wikipedia.org/wiki/Hyperthermophile#History)

[http://en.wikipedia.org/wiki/Extremophile](http://en.wikipedia.org/wiki/Extremophile)

</comment></comment><comment><USER26> After reading this article, I was reminded of [0]. The Earth's core is hot due to the presence of radioactive isotopes, both the uranium-238 and thorium-232 series occur in substantial quantities. This could alter the chemical composition of the water present due to radiolysis.

Anyone up for a hydrogen peroxide cocktail?

[0] [http://en.wikipedia.org/wiki/Chernobyl_disaster](http://en.wikipedia.org/wiki/Chernobyl_disaster)

</comment><comment><USER21> The quote would better be placed around 'discovered' rather than 'ocean' considering it's all lab experiments and a pair of wet diamonds. Not to dismiss the hypothesis/theory, which seems pretty solid (no pun intended), but it's not like we discovered a new ocean like the Europeans discovered a new continent centuries ago.

</comment><comment><USER27> One would think that water's density is smaller than the rock. Why wouldn't it eventually rise to the surface above the denser material if the surrounding rock wasn't solid?

<comment><USER28> 1) Porosity is the ratio of the volume of openings (voids) to the total volume of material. Porosity represents the storage capacity of the geologic material. On the other hand, permeability is a measure of the ease with which fluids will flow though a porous rock. Although a rock may be highly porous, if the voids are not interconnected, then fluids within the closed, isolated pores cannot move. This situation is commonly found in nature and represents a challenge for the extraction or the injection in reservoirs.

Nevertheless, I have no idea of the porosity level that could exists at those depths.

2) At 700km depth pressures are of order 21 Giga Pascals (~207000 atmospheres) and temperatures about ~1900ºC. Water is not the water we know at these conditions, it is a supercritical fluid. The line separating liquid and gas phases ended at much lower temperatures.

<comment><USER27> I thought at those depths the rock isn't solid, so why would water (or supercritical fluid) need a lot of pores to go through? Not to mention, can't supercritical fluids effuse through solids?

</comment></comment></comment><comment><USER29> Is it a closed biosphere? What's in it?

<comment><USER25> Very likely not a biosphere because of the very extreme temperatures (for any type of life anyways, even extremophiles), but a lot of things we've discovered over the years used to be thought to be impossible too!

[https://news.ycombinator.com/item?id=7888553](https://news.ycombinator.com/item?id=7888553)

</comment></comment><comment><USER30> and the moment we learn how to do fracking through 700km deep well...

<comment><USER31> We're fracking at a couple thousand meters right now, I'd say 700km is a decently-sized buffer.

</comment></comment><comment><USER32> Coming next: creationist interpretation of this in a Biblical flood narrative with reference to "opening up the fountains of the deep".

<comment><USER33> The flood story is covered in many cultures.

[http://en.m.wikipedia.org/wiki/Gilgamesh_flood_myth](http://en.m.wikipedia.org/wiki/Gilgamesh_flood_myth)

[http://en.m.wikipedia.org/wiki/Flood_myth](http://en.m.wikipedia.org/wiki/Flood_myth)

<comment><USER34> AFAIK the Epic of Gilgamesh does not include the "fountains of the deep" aspect of the Noah story that's relevant here, and also there aren't a lot of Sumerian creationists around.

<comment><USER33> I was simply pointing out that there are many flood stories in many cultures. I added another link for more references. I just know that Gilgamesh is one of the oldest. Many cultures, including the some Indians in North America, have incorporated it into their mythology.

<comment><USER35> > I was simply pointing out that there are many flood stories in many cultures

Being in many cultures isn't evidence against the story, as it seems you are trying to imply.

It could simply mean there was one huge flood and lots of cultures recorded it.

I am aware there is no scientific mechanism to cause a worldwide flood, this is explicitly about divine intervention. (i.e. a miracle, not creationism pseudo science).

<comment><USER36> Everything that happens on a geological scale leaves geological evidence. There is no such evidence for a global flood. It's not just the mechanism for _causing_ the flood that's missing, but any sign of it whatsoever. I grew up learning about and believing in a global flood, and confronting the hard truth that there is no evidence for a flood was an important part of my intellectual development.

However, since there are reasons other than reason and evidence for people to believe in a flood, no amount of reasoning or evidence will change those beliefs, so I propose we focus on the tantalizing science fiction implications instead.

<comment><USER37> The absence of evidence is not proof of the contrary. I am an atheist and I laud your dedication to evidence based reason, but don't go overboard and ignore things many people believe are true, often they do for a reason.

That said, if there never was such a flood there would likely be evidence that it never happened.

<comment><USER38> I'm curious what you think "evidence that it never happened" would look like, except for looking like the absence of evidence?

What would evidence that there was never a global flood look like? One example might be "lack of a global species disruption in the fossil layer". But that's just absence of evidence again.

<comment><USER39> You're talking about the idea of the Genesis flood, occurring some 4500 years ago, drastically rearranging the recently-created Earth's geology, wiping out every living thing except for the few that survived on a boat that landed on a single mountain in what is modern-day Turkey?

I think there are some predictions you could make there. However every single one of them is just so far divorced from what we observe that they aren't even worth enumerating.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER40> I hope they find the dinasouars like in Verne's A Journey to the Center of the Earth

</comment><comment><USER41> In the not too distant future, when water becomes a valuable commodity, we'll have "I drink your milkshake" situations that will get geopolitical very fast.

<comment><USER42> What makes you think this doesn't happen already. Arizona called in the National Guard on California during construction of tunnels out of Lake Mead. Mexico has threatened to take the US to international court over the salinity of the Colorado River. Dynamite was set off numerous times on the aqueducts that bring water to LA. Hostages have been taken and killed over the construction of dams in South America. Fresh water already is the scarcest resource we have in the American West. Far scarcer than oil by a long shot.

<comment><USER43> >Fresh water already is the scarcest resource we have in the American West.

What does that mean? I'm not sure how you'd go about quantifying scarcity in any meaningful way. Are we going by volume? Price? If price, then price per what?

<comment><USER44> You have to consider price, particularly in the American West, as desalination can make as much fresh water as you can afford.

The only thing stopping California from building massive solar-powered desalination plants is that bullying the surrounding states is (currently) cheaper and easier (politically).</comment></comment></comment></comment>


Fireflies - <AUTHOR> http://ncase.me/fireflies/ <comment><USER2> Apologies for what might be shameless self-promotion, but if you're interested in this idea, you might like my 2012 project , "The Kuramoto Model (1,000 Fireflies)." I built 1,000 microcontroller-based LED devices that synchronized with each other using radio communication, with a similar algorithm to what Nicky used. Link is here: [http://davidrueter.com/projects/2012-the-kuramoto- model.html](http://davidrueter.com/projects/2012-the-kuramoto-model.html)

<comment><USER3> Very good result although the green mind in me screams a bit when thinking about all this waste.

<comment><USER4> Hmm, my city gives away bike lights pretty frequently - they aren't as sophisticated (sadly) but it doesn't seem especially wasteful either way (at least I'd assume that a fair percentage of the riders using them would have bought some kind of light otherwise; and as long as they continue to work, I wouldn't expect them to end up in a landfill). The synchronization is especially fun.

</comment></comment></comment><comment><USER5> Yay ncase did it again! Don't forget to (re)view his project on The Parable of the Polygons: [https://news.ycombinator.com/item?id=8716538](https://news.ycombinator.com/item?id=8716538)

Playable posts are amazing. Interactivity in texts is amazing.

<3

<comment><USER6> If you like interactive posts with lots of play, check out Bret Victor's work (if you haven't already). Good start here: [http://worrydream.com/ClimateChange/](http://worrydream.com/ClimateChange/)

<comment><USER5> Fun fact which I heard on a conference about gaming: Vihart (who ncase collaborated with) worked together with Bret Victor.

Disclaimer: not sure if memory serves me right though O:)

</comment></comment></comment><comment><USER7> This is similar to a pretty famous result in networking and distributed systems about self-synchronization, which used to cause problems.

[http://ee.lbl.gov/papers/sync_94.pdf](http://ee.lbl.gov/papers/sync_94.pdf)

<comment><USER8> Fascinating! I can see how synchronization across distributed systems would cause problems -- lots of requests against the same type of resource at the same time, for example, resulting in a thundering herd ([https://en.wikipedia.org/wiki/Thundering_herd_problem](https://en.wikipedia.org/wiki/Thundering_herd_problem)) -- but also how it could be absolutely what you want (like if you want to synchronize clocks across systems, which I guess is exactly what's going on in the OP [https://en.wikipedia.org/wiki/Clock_synchronization](https://en.wikipedia.org/wiki/Clock_synchronization)).

</comment></comment><comment><USER9> I did the same thing a few years ago! My fireflies didn't move around though.

[https://www.michaelfogleman.com/static/fireflies/](https://www.michaelfogleman.com/static/fireflies/)

<comment><USER10> Nice.

I saw your comment: "The cells need not have identical individual frequencies to reach sychronization."

This seems counter-intuitive to me.

<comment><USER9> They can't be too out of whack, but they can vary.

</comment></comment></comment><comment><USER11> I did not realize you could scroll down on first viewing. If this weren't at 400+ upvotes when I saw it, I would have thought that was it.

<comment><USER12> Same here. I'm glad I scrolled down and resized my screen. I didn't notice it my first viewing actually. I only noticed it when I called my wife down to check it out later.

</comment></comment><comment><USER13> I think the example works more quickly than it should due to the line "if(ff.clock>1) ff.clock=1;" Every time the clock goes over 1, wouldn't you mod the clock value, not set it to 1 exactly?

<comment><USER14> No, partly because fireflies take a certain amount of time to "charge" so jumping mid cycle might not be plausible physically.

So what this line does (which is in the section of code where a flash alters the fireflies around it) is that after advancing the other fireflies clocks, if any are over 1 then it puts them in the right state to flash on the next time they're evaluated. If you mod it, then you would have the logic:

"if I'm a firefly and see my neighbour flash while just about to flashing myself, don't flash but reset my clock to part way through the cycle"

rather than

"if I'm a firefly and see my neighbour flash while just about to flashing myself, flash as well"

Edit - setting it to one ensures that each neighbour can't keep adding to the clock, advancing it to a random point in the cycle.

<comment><USER15> If the fireflies take that time in their clocks to "charge the light", could it be that when they nudge their clock once or more in the cycle, the intensity of the light is a bit lower than it would normally be?

<comment><USER14> Interesting question. I honestly thought that the process was actually to _reset_ the clocks not move them forwards, that's how I've simulated it in the past.

</comment></comment></comment></comment><comment><USER16> Beautiful, educational and clever. I love it.

On the subject of fireflies and emergent patterns, RadioLab did a wonderful podcast on the subject as well a few years ago: [http://www.radiolab.org/story/91500-emergence/](http://www.radiolab.org/story/91500-emergence/) This piece very much reminded me of that.

</comment><comment> m-j-fox Nature's PLL.

[https://en.m.wikipedia.org/wiki/Phase- locked_loop](https://en.m.wikipedia.org/wiki/Phase-locked_loop)

</comment><comment><USER17> > But whenever you shine, you inspire those close to you to shine too, a > little bit sooner than they otherwise would have. And those close to you, in > turn, inspire those close to them.

This is adaptation to input disruption on a network of brain impulses. Fascinating that so much correlates with our own perception and technologies.

Really great interactive post both informative and engaging.

</comment><comment><USER18> Not on the coding side, but the inspiration. . . For those of us in the USA, there is a much more accessible version of synchronous fireflies at Great Smoky Mountains National Park in Tennessee. I lived there for a few years and went multiple times[1].

The dates get announced a month or so beforehand, and tickets are based on a lottery system since it only[2] occurs on one side of one river for less than a mile. You can technically also hike in if you're ok with 8 or so miles near sunset and then the same amount out in the pitch black. I believe that is frowned upon, but very few people do it that way (I was the only one the year I couldn't get tickets and decided to hike).

[1] [https://www.flickr.com/photos/23215983@N02/albums/7215764507...](https://www.flickr.com/photos/23215983@N02/albums/72157645075559534)

[2] Not exactly only, but certainly the most strongly.

</comment><comment><USER19> What an extremely nice interactive read. Works good on mobile. And it applies the biological lesson to human life, which is a nice way to finish a sermon. Article. Well done.

<comment><USER20> Yup ditto. A quick superb from me

</comment></comment><comment><USER21> Kind of curious how it works, when you inspect it, there's just a canvas, the fireflies don't seem to be individual, so no sense of "objects" or "individual entities"

open source time to read

but with regard to say if it was a real-time rendered animation, then calculating the point of origin and affecting the nearby fireflies... hmm

the view clock part was particularly impressive though I could see it as a state thing, still so many of them on the same page, not crashing the browser or something interesting. Maybe I'm over thinking it.

edit: I didn't look at the scripts though below the canvas.

<comment><USER22> Canvas is pretty performant. WebGL is even more performant. You can easily have a few thousand things on the same page at a time.

<comment><USER21> They have states right? I'm curious how that is like a JSON string or something to access each thing and change individually? I can go read haha

</comment></comment></comment><comment><USER23> Reminds me of the Fireflies[0] model included in NetLogo[1].

[0] [https://ccl.northwestern.edu/netlogo/models/Fireflies](https://ccl.northwestern.edu/netlogo/models/Fireflies) [1] [http://ccl.northwestern.edu/netlogo/index.shtml](http://ccl.northwestern.edu/netlogo/index.shtml)

</comment><comment><USER24> This is neat.

Did they ever figure out _why_ Thailand fireflies do this, instead of just how?

<comment><USER25> I suspect it helps avoid being eaten. Anything trying to eat them is presented with too many bright spots to track, then nothing to see.

<comment><USER24> Wouldn't that also be true of normal fireflies? It's pretty hard to track a single firefly if there's a bunch of them in the area.

<comment><USER25> Not so much, there's no competition, so it's easier to track. I used to collect freflies in a jar as a kid. Seems like a similar idea to schools of fish, herds of antelope, etc. Stay together (even if defenseless) and predators have a hard time picking an individual to hunt.

<comment><USER26> Ah, the paradox of choice (Firefly Edition).

</comment></comment></comment></comment></comment><comment><USER27> This is fasinating topic, I recently tried to understand what happens to this type of model if you perturb it with heavy-tailed noise.

[http://www.sciencedirect.com/science/article/pii/S0378437116...](http://www.sciencedirect.com/science/article/pii/S0378437116306768)

</comment><comment><USER28> The background noise is so soothing. [http://ncase.me/fireflies/sounds/forest.mp3](http://ncase.me/fireflies/sounds/forest.mp3)

<comment><USER29> Yeah, although my volume is down low and I opened the page in another tab while I was reading. By the time the sound permeated my consciousness, I thought that I had a hard drive going bad in my NAS next to my laptop.

</comment></comment><comment><USER30> If anyone is interested in this synchronization process or how it relates to synchronization in general, I highly recommend 'Sync' by Steven Strogatz. It's one of the best popular science/math books I've ever read, and Strogatz is a mathematician at the heart of the research, and a great writer as well, so you really get the story from someone who is a world expert, rather than an interested journalist.

</comment><comment><USER10> My only hang-up with the explanation/simulation is, why do the fireflies all have clocks that run at the same duration as one another?

I understand advancing your clock to synchronize flashes, but doesn't this presuppose that the clocks run at the same speed?

When I turned on "Show Clocks" in the simulation it indeed looked like the clocks ran at identical durations. Seems like this would be difficult in nature.

<comment><USER31> I imagine if they started at wildly different speeds it would still converge but the convergence would take longer.

<comment><USER32> The article only talks about changing the phase on fixed amount, nothing about fixing the frequency.

</comment></comment></comment><comment><USER33> Very cool. This was an interesting paper on synchrony in the brain, and how it's related to consciousness - [https://www.nature.com/articles/ncomms10340](https://www.nature.com/articles/ncomms10340)

</comment><comment><USER34> Reminded me of another phenomenon, the one occurring to metronomes on the same surface: [https://www.youtube.com/watch?v=5v5eBf2KwF8](https://www.youtube.com/watch?v=5v5eBf2KwF8)

</comment><comment><USER35> It would be even more impressive if the fireflies' internal clock was ticking at slightly different speeds. As it is now, once they're synchronized, turning the sync mechanism off has no effect and they stay synced forever.

</comment><comment><USER36> Why would a firefly that sync survive more than one which doesn't?

<comment><USER37> Good question. My initial guess: it is easier for predators to detect/catch fireflies that blink out of sync with the rest of the flock. If all blink in perfect synch, it's just a big flash of light to the predators.

</comment></comment><comment><USER38> After the point when the whole swarm is synchronised there seems to be no further nudging, does this make sense? Am I missing something? Very interesting, just not sure I understand.

<comment><USER39> It's because of what dyarosla pointed out in their comment: [https://news.ycombinator.com/item?id=14452832#14456254](https://news.ycombinator.com/item?id=14452832#14456254)

</comment></comment><comment><USER40> Is there some inverse of the firefly's sync protocol that if they all followed would turn a synchronized swarm back into a chaotic one?

<comment><USER41> In real fireflies, the individual clocks have slightly different frequencies. The inverse of the protocol is no protocol: stop syncing and let the blinks slowly fall back into chaos.

</comment></comment><comment><USER42> I wonder if you need the random scattering for this to work, or if it would still work if the fireflies formed a hollow circle.

</comment><comment><USER43> The view source of this is amazingly clean and refreshing to read. Great learning example, thanks!

</comment><comment><USER44> Incidentally, this is a very powerful model for neural synchrony as well.

</comment><comment><USER45> Does the 137.5 degrees has something todo with this?

</comment><comment><USER46> ot, the patreon link comes up with an empty white page and pukes all kinds of js errors to the console for me

</comment><comment><USER47> This is nice, I really enjoy this

</comment><comment><USER48> this is pure genius! i love fireflies!

</comment><comment><USER49> Nature has the best algorithms, don't it folks?

I have a question about a detail.

The rule is:

1\. When you see a nearby neighbour flash, nudge your own clock forward.

2\. That's it.

My question is -- when the fireflies are firing at the same time, they see each other flash, so they all nudge their clocks forward, correct?

Assuming they don't nudge their clocks forward at the same amount, they would fall out of sync, correct? But they stay in sync, so they must nudge forward at the same amount...is this right?

So my question is -- if everyone keeps nudging their clocks forward, why don't they keep speeding up? They do appear instead to continue flashing at the same steady rate.

Does this mean that there ought to be another detail in the rule, such as,

If you see a neighbour nearby flash, when you are not flashing, nudge your clock forward by a bit.

? Or is the perspective I just said missing something?

<comment><USER50> At least in the Kuramoto model, it's a little more complicated than the OP makes it sound (but not much). Step 1 is more like "if you see a flash, bump your clock closer to midnight."

Specifically, an ODE is given for firefly $i$'s phase angle $ \theta_i$

$$\dot\theta_i = \omega_i + K / N \sum_{j=1}^N \sin(\theta_j - \theta_i)$$

This gets interesting because the flies natural frequencies $\omega_i$ are also assumed to be randomly distributed. So you don't get perfect phase- synchronization--flies with fast natural frequencies lead the pack as it loops around the phase ring, and flies with slow natural frequencies are dragged along at the back. Relative to the mean phase, your excess phase approaches a smooth increasing function of your natural frequency. But, for high enough values of $K$, you do get frequency-synchronization--everyone oscillates at the average frequency.

(For low values of $K$, or too-large natural frequencies, "rogue oscillators" emerge in a SNIPER bifurcation. They zoom around the phase ring at a different frequency, briefly slowing as they pass through the cloud of synchronized oscillators. Also applies for too-slow rogues.)

In the video and the OP's simulation, it looked the natural frequencies were all pretty similar, if not the same. However, there was a second addition that is not in the original Kuramoto model (but is in most subsequent models): rather than observing all other flies, only observe nearest neighbors. This can be added by putting a symmetric boolean adjacency matrix $A_{i,j}$ right before the $\sin$ in the previous equation.

This has the effect of making excess phase a smooth function of not only the natural frequency, but also some structural feature imposed by the network. In random networks like Erdos-Renyi, this feature is the node degree, but in the video it looks like it might be the long axis of the bush (so, like, one of the eigenvectors of the graph Laplacian).

(In general, coupled oscillators, such as circadian gene clocks, show this smooth dependence of excess phase on per-unit heterogeneities, which is the topic for the first half of my PhD dissertation. The second half is figuring out what the heterogeneities are when you only have recordings of the dynamics to go by.)

<comment><USER51> > $$\dot\theta_i = \omega_i + K / N \sum_{j=1}^N \sin(\theta_j - \theta_i)$$

What's the quickest way to preview that (without needing a hosted service)?

I just made this small LaTeX document (I'm amazed I knew this by heart, I typed this manually maybe thrice in my life):

        \documentclass{paper}
        \begin{document}
        $$\dot\theta_i = \omega_i + K / N \sum_{j=1}^N \sin(\theta_j - \theta_i)$$
        \end{document}
        <esc>:wq
        pdflatex tmp.tex && evince tmp.pdf && rm tmp.*

but that's still quite a bit of extra work just to view it. Do you know a better way to do it?

<comment><USER52> I use this solution sometimes.

[http://www.HostMath.com/Show.aspx?Code=%5Cdot%5Ctheta_i%20%3...](http://www.HostMath.com/Show.aspx?Code=%5Cdot%5Ctheta_i%20%3D%20%5Comega_i%20%2B%20K%20%2F%20N%20%5Csum_%7Bj%3D1%7D%5EN%20%5Csin\(%5Ctheta_j%20-%20%5Ctheta_i\))

</comment></comment></comment></comment><comment><USER53> Probably one of my favorite things I've seen on HN in a long time. The perfect synthesis of tech explanations to biological phenomena. The way the entire page fits together to teach is just beautiful.

Why it's sitting down on the second page with just a few upvotes is beyond me.

</comment><comment><USER54> One of the things I miss from growing up in rural Virginia.

</comment><comment><USER55> Parable of the polygons is extremely questionable. For one, it attempts to have its cake while eating it too, by pretending it's an abstract demonstration about choices while explicitly calling out to hot topics in diversity, implying a clear causal link. For another, the model involves discrete agents on a discrete grid making decisions based on their immediate 8 square neighborhood, with no persistence or hysteresis, which does not at all match the real life domain it is attempting to model.

If you changed the grid geometry, changed the action radius, or added a more complicated decision mechanism, it is likely to result in a completely different outcome. It is more like a cellular automaton than a sociological model, compounding design choices, not agent choices.

It should probably be called Parable of the Quantization Error instead and held up as an example of an explorable explanation being misused for propaganda purposes, using its medium to present a false image of impartiality.

<comment><USER56> If you're so passionate about it, you should go implement these changes to show how the model fails. I would read that, if it were done well. It's not obvious to me that simply changing the radius or grid geometry would have the effect you claim.

Your objection is just that the model is too simple, but everyone knows linear regression predicts quite a lot, quadratic polynomials estimate physical motion very well, etc.

On the other hand, I don't think the authors make the claims about faithfully and objectively measuring reality that you say they do. You're building up a straw man there.

<comment><USER57> FWIW, the majority of the first page of this user's comment history (6/10) are complaining about feminism in some fashion.

(I don't generally like looking at people's comment history, but one, you're absolutely spot-on that it would be easy to change the simulation - it's public domain and it's in JavaScript, this is _Hacker_ News, if you don't know how to edit the JS console yourself there are tons of people who will gladly help if you ask, so the lack of curiosity is interesting. And two, I've seen some sort of shift in more vocal MRA-adjacent / alt-right-adjacent viewpoints on this site in recent weeks and I've been kind of curious where it's coming from.)

Anyway, in the hope of not dragging this too far off-topic: 'tnone, do you have a specific change you'd like to see implemented in the simulation? I'd be happy to implement the change and rehost it and see what happens. I think there _are_ genuine criticisms to be made (for instance, [https://github.com/ncase/polygons/issues/9](https://github.com/ncase/polygons/issues/9) sounds worth some investigation, despite the phrasing of the comment thread). But given how easy it is to apply actual data to these questions, I think we should do that to avoid FUD.

In particular, how about changing the radius to be the surrounding 24 squares (two steps out, instead of one), or making it less likely that an individual polygon will move again shortly after it has moved?

<comment><USER56> Since I wrote that comment I feel the itch to do it myself :) He said topology, but I don't think he meant what I'm thinking of: a torus! A Mobius band! The projective plane! My curiosity is getting the better of me.</comment></comment></comment></comment>


29 celebrities that you didn't know was really smart - <AUTHOR> http://finance.yahoo.com/news/the-30-smartest-celebrities-in-hollywood-175417855.html

<comment><USER2> was -> were</comment>


Remnants of the Biosphere - <AUTHOR> http://bldgblog.blogspot.com/2010/01/remnants-of-biosphere.html

<comment><USER2> I'm actually surprised at how well it's all held up (particularly the "rainforest" area. Anyone know if they are doing _any_ maintenance to it at all?

</comment><comment><USER3> We made a small trip to see this when I was growing up in AZ. Mostly forgot about it until now, very cool to see.

</comment><comment><USER4> Looks like Myst to me. Beautiful.

</comment><comment><USER5> Blogspam. Original: [http://bldgblog.blogspot.com/2010/01/remnants-of- biosphere.h...](http://bldgblog.blogspot.com/2010/01/remnants-of- biosphere.html)

<comment><AUTHOR> What are you talking about? That is what is linked here.

<comment><USER6> Actually, it appears the link was re-written in at least one of these submissions, probably because it was blogspam.

<comment><AUTHOR> Ah, interesting. This one always had this URL, the other did get changed though.</comment></comment></comment></comment>


Nantucket: an accidental limerick detector - <AUTHOR> http://www.daniellesucher.com/2012/04/nantucket-an-accidental-limerick-detector/ <comment><USER2> Some day I may turn this into a chrome extension to highlight limericks on arbitrary pages. It would be joyous to see a highlighted section of some random wikipedia page pop out to be a limerick!

</comment><comment><USER3> As someone who was drawn back into programming by the NLTK while in a creative writing program, I say bravo!

This one especially moved me:

      Amorite and the Girgasite
      And the Hivite and the Arkite
      and the Sinite And
      the Arvadite and
      the Zemarite and the Hamathite

I imagine it would be fun to do this with heroic couplets, too. If I'm not mistaken, I think the idea has been applied to random tweets.

<comment><USER4> I made a bot that would fetch Twitter posts and re-tweet any it detected were 5-7-5 haiku. The syllable counter was just a series of regex replacements, loosely inspired by Metaphone, but it was about 95% accurate on my dictionary of 300,000 words.

<comment><USER3> Have you seen the New York Times haikubot? (Maybe you wrote it?)

</comment></comment></comment><comment><USER5> I think the rhyme definition is wrong. To me a rhyme has to be have the same phonemes from the coda of the last _accented_ syllable to the end of the line.

<comment><USER6> Yes, without accent detection, the 'limericks' it finds can generally only be read with forced stresses, and the rhyming schemes it winds up with can be quite weak (rhyming an unstressed 'the' at the end of two lines, for example).

Ironically, by not knowing how to properly handle a stress-unstress syllable pair at the end of a line, this program would completely miscue on any limericks it finds with a first line that ends in 'Nantucket'

</comment></comment><comment><USER7> If you like this you might like [https://twitter.com/anagramatron](https://twitter.com/anagramatron)

<comment> guard-of-terra What are these anagrams for? What's the subject?

<comment><USER8> It appears that it retweets pairs of tweets that anagram each other. The tumblr page shows it more clearly:

[http://anagramatron.tumblr.com/](http://anagramatron.tumblr.com/)

</comment></comment></comment><comment> guard-of-terra Yandex has Autopoet that writes poems using search queries as dictionary.

[http://autopoet.yandex.ru/](http://autopoet.yandex.ru/) It supports quite some poetic forms including limerick.

Unfortunately it only handles Russian. But poems are actually pretty awesome.

</comment><comment><USER9> Is there a (freely available) online dictionary(?) which gives the pronunciation of English words?

<comment><USER10> Get the CMU pronouncing dictionary as explained in the README: [https://github.com/DanielleSucher/Nantucket/](https://github.com/DanielleSucher/Nantucket/)</comment></comment>


Why I'm finally convinced it's time to stop saying "you guys" - <AUTHOR> http://www.vox.com/2015/6/11/8761227/you-guys-sexism-language?utm_source=digg <comment><USER2> I'm torn about this.

On the one hand, I can see how it isn't the most inclusive language. Saying "you guys" is like using "he" as a default pronoun and kind of outdated in a world that's trying to be more inclusive. Just because it sounds natural to say doesn't mean it's proper.

On the other hand, "you guys" is the New England/Northeast version of you plural, and is the most natural for me to say. "Y'all" sounds stupid coming out of my mouth, "you all" sounds like I'm purposefully trying not to say y'all, "you people" is decidedly not acceptable, "you girls" sounds even MORE sexist...

Sometimes, you just can't win.

<comment><USER3> >Sometimes, you just can't win.

folks? people? etc?

"Alright folks, let's get back on topic."

"Alright people, let's get back on topic."

"You folks going to happy hour?"

</comment></comment><comment><USER4> "You guys" is gender neutral to me.

</comment><comment><USER5> "You guys" is not only used to denote an all-male or mixed-gender group.

Evidently, Jenée Desmond-Harris is unaware that girls also use "you guys" to refer to their _all-female_ peer groups!

It's clear from the all-female usage that "you guys" does not mean anything like "you group of males, and ... some less important people".

</comment><comment><USER6> Its a necessary part of speech, similar to the german Ihr (yall) and Ihren (all yall). It sounds funny to some Americans, but they use other made-up crutches to work around it. If yall used it regularly, it'd seem perfectly natural to yall.

</comment><comment><USER7> Previous thread discussing this: [https://news.ycombinator.com/item?id=9211180](https://news.ycombinator.com/item?id=9211180).

</comment><comment><USER8> Another reason everyone should get comfortable with using y'all as a real/acceptable word in English.

<comment><USER4> I don't know why, but I really don't like saying or hearing "y'all"

<comment><USER5> It's still currently an element of some dialects of American english that will stigmatize you as belonging to a certain class.

People not belonging to such a class use "y'all" jokingly in situations where everyone knows it.

</comment></comment></comment><comment><USER9> what the fuck</comment>


QBASIC Programming for Kids - <AUTHOR> http://www.tedfelix.com/qbasic/ <comment><USER2> Oh wow, that's a blast from the past!

Had lots of fun with QBasic as a kid :)

<comment><USER3> I have a fond place for QBasic. I started to teach myself programming (as a 14 year old in the 90s) with GW Basic because my dad's older computer had disks and a manual. I quickly learned that if I upgraded to DOS 5 I could get QBasic and I did so along with a book from the library on QBasic programming. I tore into that book. I think I renewed by checkout as many times as they let me. I never stopped programming everyday from that day until well into adulthood. Now I have had some days where I haven't programmed in the last 25 years. QBasic was a life changing moment for me.

<comment><USER2> I'm the same.

QBasic, GW Basic, Commodore 64, those were the big ones for me as a kid.

Without them, I probably wouldn't be a programmer today.</comment></comment></comment>


UK government to create their own internet - <AUTHOR> http://www.independent.co.uk/life-style/gadgets-and-tech/news/theresa-may-internet-conservatives-government-a7744176.html <comment><USER2> I'm struggling to find a difference between these proposals and those of governments like. Genuine freedom is dead - governments can't tolerate true freedom.

<comment><AUTHOR> I suppose the difference is this government won't actually want to pay for the great firewall!

</comment></comment><comment><USER3> There are previous major discussions:

Here: [https://news.ycombinator.com/item?id=14382184](https://news.ycombinator.com/item?id=14382184)

And here: [https://news.ycombinator.com/item?id=14374533](https://news.ycombinator.com/item?id=14374533)

</comment><comment><USER4> Mrs May, tear down this (fire)wall.</comment>


The Rise of the Machines - <AUTHOR> http://www.nytimes.com/2008/10/12/opinion/12dooling.html

<comment><USER3> Quants had almost nothing to do with this crisis. The problem wasn't that the computers knew too much, it was that they knew too little. They were fed best- case-scenario risk analyses. Of course the loans looked good if you assumed the housing market was going to keep going up.

</comment><comment><USER4> "...because we all know that no one understands credit default obligations and derivatives, except perhaps Mr. Buffett and the computers who created them." Statements of this sort are getting really tiresome.

Will some of the derivative designs be made public as a result of the congressional hearings? Shouldn't that be part of the investigation's purview?

<comment><USER5> And why single out Mr Buffet on understanding them? He is a clever guy - <USER2> he is not very keen on derivatives.

</comment></comment><comment><USER6> Ex-hedge quant here. Here's my semi-informed take.

Quants didn't write most of these toxic derivatives, and they weren't conceived by computers, at least not as far as I know. Though technological modeling was necessary to value many of these securities (Monte Carlo methods, etc.) I really doubt that any serious financial company would allow a computer to conceive of derivatives to any meaningful extent. But I could be wrong.

These contracts, in many cases, were _designed_ to be complex beyond comprehension, but AI methods don't help make them comprehensible to machines. I think of these 500-page derivatives contracts as similar to long software EULAs (which are intended to be so long and dry that 95% "TL;DR" and click "Accept", while even the diligent 5% miss details)... or to the packets in which health insurance companies detail exclusions. The things are intended to be virtually incomprehensible, making it easy for the writer to fool not only his customers, but also his bosses, by sweeping low probability risks (e.g. an "unprecedented" nationwide drop in real estate during a strong economy such as that which existed in mid-2007) under the rug.

Quant funds were not hammered because (loosely speaking) the computers emergently "tricked" them. They got whacked because all the models were trained on the past, and 8/2007 - Pres. has been unprecedented. Also, the fact that a large number of seemingly independent agents (funds) have piled into the same few strategies means that an unwind from one will lead to losses for many.</comment>


Magic Ink: Information Software and the Graphical Interface (2006) - <AUTHOR> http://worrydream.com/#!/MagicInk

<comment><AUTHOR> I recently discovered this five-year old essay by Bret Victor who, coincidentally, has another article on the front page right now (<http://news.ycombinator.com/item?id=3212949>). It discusses how to improve user interfaces by focusing less on interaction and more on information/graphic design.

It's long but worth your time. If nothing else, have a look at the proposed redesign of Amazon search results, and the hypothetical flight planning website that looks eerily similar to Hipmunk's eventual design.</comment>


The Glorious Horror of TECO - <AUTHOR> http://goodmath.scientopia.org/2010/11/30/the-glorious-horror-of-teco/ <comment><USER2> > Richard Stallman and James Gosling wrote emacs - the editor macros for TECO.

Actually the original TECO Emacs was written by Guy Steele, RMS took it over later. I remember using this on Tops-20.

James Gosling wrote an Emacs in C, to run on Unix. It had a "Mocklisp" macro language. I remember reading the source code at CMU.

RMS then wrote GNU Emacs, with the better "elisp" macro language.

Both of these were inspired by the Emacs written in MacLisp by Bernie Greenberg.

</comment><comment><USER3> Ah the fun of TECO where it was standard practice to type your name into the buffer and hit 'esc' (start program for TECO) just to see what it would do.

</comment><comment><USER4> hkex$$</comment>


What Could Raising Taxes on the 1% Do? Surprising Amounts - <AUTHOR> http://www.nytimes.com/2015/10/17/business/putting-numbers-to-a-tax-increase-for-the-rich.html <comment><USER2> "Right now, the wealthy pay too little," Hillary Rodham Clinton said at this week's Democratic debate in Las Vegas, "and the middle class pays too much."

Careful folks, that's focusing your attention to the wrong areas. Look at the (wo)man behind the curtain. A flat-tax is what is needed.

<comment><USER3> Ah yes, the flat tax. The thing talked about on AM conservative talk radio all the time.

Flat taxes like sales taxes are regressive and hurt the poor. Take for example Mississippi which has sales taxes on food. Disgusting.</comment></comment>


Google shuts down Burger King's cunning TV ad - <AUTHOR> http://www.theverge.com/platform/amp/2017/4/12/15277278/google-home-burger-king-whopper-ad-campaign <comment><USER2> Thank god. This has so much potential to do so much annoying damage.</comment>


Ask HN: What are some websites currently using the .app domain? - <AUTHOR> I was wondering on sites already using this domain, so far I've only found: https://cash.app/ <comment><USER2> [https://get.app/](https://get.app/) has a gallery.

<comment><AUTHOR> thanks

</comment></comment><comment><USER3> The TLD just entered general availability three days ago! There aren't going to be a lot of sites using it yet.</comment>


Ask HN: How to bring in an external CEO for young/successful startup? - <AUTHOR> See title. I have bootstrapped two different businesses. Company A is doing very well ($100k/mo revenue), but it started to stagnate a couple of years ago.
At that point we started Company B. I invested nearly $2mil and 2 years into its development and we just finished building it 2-3 months ago. It currently makes $10k/mo and has a very solid business plan that we think will create a very viral growth engine for it.
We were just beginning to execute on this business plan when market changes suddenly allowed for Company A to have explosive growth. We suddenly have a vision for how we can turn Company A into a $100mil/yr company. This falls under "good problems", but as the Founder/CEO of both I also have the very painful decision that we need to basically abandon Company B to go all in on Company A.
With that being said, Company B is generating money and is almost ramen profitable, has a lot of money invested in it, and I still believe in it just as much as I did before.
I have considered trying to sell it, but I think at this point it won't get anywhere near its value, or what it would be able to get with even just a year of effort put into growing it.
So at this point, I am exploring other options, with one attractive one being to let someone else (or some other group) assume the role of CEO in return for a significant equity package (since it is bootstrapped entirely with my money, I own 100% of the company right now). That way I can personally go all in on Company A, but Company B is still left in good hands and can grow to its potential.
Is this even realistic and if so how would I even begin to go about doing this? I know how I'd go about selling Company B, but we are not in Silicon Valley (east coast), and I am not particularly well connected so I'm not sure who I'd even start talking to about such a possibility.
Basically, how do I go about finding an external CEO to run Company B or am I stuck selling it for 1/10th of its investment? <comment><USER2> Such an awesome problem to have, but still a problem. Good on you for recognizing too that it would be too much to try and do both yourself. Sometimes our egos get in the way of the best decisions and you seem to have solved that problem already.

I hired a CEO a while back to run a company that I acquired through some less then conventional means, but wound up with 100% ownership in. I was and still am a CTO at another company that is quite separate but I always am on the lookout for deals which is how this deal fell into my lap. Anyway, I didn't have any contacts in the main industry the company operated in, but obviously could understand the model and technology (or I would've skip it). So I reached out to suppliers and businesses that were in the same vertical but not competitors and started asking lots of questions. Bought quite a few lunches/dinners/drinks to learn all that I could and to ask them point blank if they knew of anyone that might be a fit for what I needed. This took me a little while, but I generally refuse to use recruiters, so to me it was the best way to come up with someone I felt had the right skill mix and that I could cut a deal with that involved more than just a salary. Once I heard a few names pretty consistently then I approached them and met with them all, eventually cutting a deal with one to lead the company while I kept my day job.

My 2 cents. This has worked out great for me, but partially because I am good at leaving him to do his job and I don't interfere or get in his way. He gives me regular reports, and calls me for large decisions or things he feels I need to be in the loop on, since it is still my money and company in the end. However, I'd say 85-90% of the time I always go with his recommendation, after all I hired him as the expert. It hasn't always been the right call of course, but neither have my decisions in my career either, so who cares, fix it and move on. I only bring this up because if you choose this route over selling you have to manage things forward and not interfere with the business, you essentially are a board chairman. That doesn't mean you don't have input etc, just that you have to be careful how you approach it so you don't destroy the employee trust in their leadership. Just like founders who constantly bounce in and out of areas thinking they are making things better instead of using the leadership they hire to get what they need done, it destroys company's long term and limits the growth of the company.</comment>


The Crushing Cost of Health Care - <AUTHOR> http://online.wsj.com/article/SB10001424052702304441404577483050976766184.html?mod=WSJ_hpp_LEFTTopStories <comment><USER3> The thing that most people don't realize and the media surprisingly never talks about is the fact that Medicare and Medicaid consistently underpay for treatments given. Somehow the government gets away with only paying 2/3-3/4 of the actual cost, leaving the hospital to foot the bill. It's so bad that many clinics don't accept Medicare because it simply causes them to hemorrhage too much cash.

<comment><USER4> Yes, I learned this from a talk at the University of Chicago Hospitals -- Medicare/Medicaid almost always paid less than a dollar for every dollar in costs that they incurred (I think the quoted average number was closer to 50 cents on the dollar but I could be wrong). The only way they made up for these costs was from patients with certain types of private health insurance (not all types because some like Blue Cross had essentially negotiated rates very very close to cost). Without these patients, the hospital would not have been able to afford the Medicare and Medicaid patients.

</comment></comment><comment><USER5> I know the term "Death Panels" pushes a lot of peoples buttons, but it sounds to me like a government agency that decides that someone, and later when money is more tight that some-subset is too expensive, is basically just that - <USER2> Death Panel.

As rough as it is to stomach sometimes, I'd have to say that the people who "deserve" better treatment are the ones who worked hard and smart and are able to pay for it. Life is not fair, and saving for terrible contingencies helps mitigate those very risks.

<comment><USER6> More importantly, it ignores the fact that this already happens, except it's insurance companies, not a government agency, that do it.

"Life is not fair, and saving for terrible contingencies helps mitigate those very risks."

For many hard-working people, it's impossible to save enough, or to have saved enough, for such contingencies. The simplest example would be a young couple whose child has some wildly expensive condition.

<comment><USER5> That was the point about "life is not fair" and again about "mitigating" the risks. I didn't say it removes the risks. Nothing does, not even big brother taking all our personal responsibility and freedoms away.

</comment></comment></comment><comment><USER7> Poor title. It's not clear that these very expensive patients really account for the bulk of the cost problem we're facing.

On the other hand, it is worth considering the ethics of such a situation. At least as depicted in the article, it seems hard to understand how prolonging treatment in this case really benefited the patient, regardless of the cost.</comment>


Ask HN: What's a good site to find iOS jobs in NY, Boston or Remote? - <AUTHOR>

<comment><USER2> [http://gun.io](http://gun.io). You need github to apply.</comment>


Convicted of Sex Crimes, but with No Victims - <AUTHOR> https://www.nytimes.com/2020/08/26/magazine/sex-offender-operation-net-nanny.html <comment><USER2> [http://archive.is/XUEO3](http://archive.is/XUEO3)</comment>


Private, Encrypted File Sharing - <AUTHOR> https://send.firefox.com <comment><USER2> This is exactly the alternative to lockify.com I was looking for a few days ago.

</comment><comment><USER3> Pretty cool. Didn't know this service.</comment>


(2014) Deadmau5's Gets Cease and Desist for His Nyan Cat Ferrari - <AUTHOR> https://mashable.com/2014/08/30/ferrari-deadmau5-cease-and-desist/ <comment><AUTHOR> Similar reading from WaPo: [https://www.huffingtonpost.ca/2014/08/28/deadmau5-purrari- ce...](https://www.huffingtonpost.ca/2014/08/28/deadmau5-purrari-cease-and- desist-ferrari_n_5732422.html)

</comment><comment><AUTHOR> TLDR; Ferrari != John Deere - sounds like registered trademark violations at play - more so than just the paint job.

Seems like when you buy an exotic car its good practice to not name it something that rhymes with the manufacture's name. The "Purrari" also has custom badges that remix the Ferrari logo into the Nyan Cat theme. Which IMO might be the straw that broke the camel's back - and got Ferrari's attention not to mention the media spectacle it creates.</comment>


Windows 10 advertisment popup on Windows 7, came with Windows Update - <AUTHOR> https://www.reddit.com/r/Windows10/comments/38129w/windows_10_popup_legit/

<comment><AUTHOR> More Info: [http://venturebeat.com/2015/05/31/microsoft-starts- prompting...](http://venturebeat.com/2015/05/31/microsoft-starts-prompting..).

This Windows update KB installs it: [https://support.microsoft.com/de- at/kb/3035583/en-us](https://support.microsoft.com/de-at/kb/3035583/en-us)

</comment><comment><USER2> Approx two months of waiting for the Windows 10 update to roll out. July 29th 2015 is when the update comes out.

You lose Media Center, and MS Harts and some other stuff. No sure about compatibility with older programs.</comment>


Multicast in Ruby: Building a Peer-to-Peer Chat System - <AUTHOR> http://tx.pignata.com/2012/11/multicast-in-ruby-building-a-peer-to-peer-chat-system.html

<comment><USER2> 1) Do NOT use 188.8.131.52! I cannot emphasize this enough. This is the IPv4 all hosts address and should not be used for mcast applications. IANA has reserved the 239/8 range for intra-AS mcast applications. Use it. In general using any address in the 224/8 range is bad for mcast application development. But especially do not use anything in the 224/24 range.

2) Does Ruby automagically take care of setting the destination Ethernet address to an IP multicast MAC? I don't see any mention of this but it's pretty important.

As insaneirish rightly points out, it's really only multicast if it crosses an L2 boundary and a multicast routing protocol like PIM or DVMRP is involved. This writeup will most likely only result in poorly formed packets being broadcast on a local subnet.

</comment><comment><USER3> Some thoughts about multicast. This works great on a single subnet, but it's likely to just be treated as broadcast (in the absence of IGMP snooping on the switches). Making multicast work outside a single subnet (even off of the same router) requires multicast routing to be enabled (and it's usually not, because doing it without breaking things is complicated).

Now for some comments that apply more generally to multicast (and not for this low volume chat application). Setting TTL=1 for multicast traffic is often bad, because it causes the first hop router to have to generate an ICMP time exceeded message. Having to do this lots and lots and lots of times per second can crush some legacy router platforms. Speaking as someone who builds networks just for multicast, we instruct our application developers to always use a large TTL and tell them we will ensure it doesn't go further than it should. It's just a practical course of action.

But good job!

<comment><USER4> > Speaking as someone who builds networks just for multicast

I heard about IP Multicast more than 10 years ago. But it never took off. Or at least I thought so.

I am really curious what are practical applications of the networks you build. Do your clients use them for broadcasting video streams or something else?

<comment><USER5> IP multicast is used quite extensively for streaming video. Mostly in combined voice/video/data networks for IPTV (think hotel rooms, but also network service providers), as well for stuff like e.g. security cameras.

On the public Internet it's still virtually unheard-of afaik, and I expect it to remain that way indefinitely.

(I used to work on IP multicast support for network switches.)

<comment><USER6> It used to be pretty popular on the public Internet back when a lot of the use was by academic institutions.

I remember seeing some NASA stuff (?) on there before the local university management decided to put up a firewall and break all the interesting IP apps.

ref. <https://en.wikipedia.org/wiki/Mbone>

</comment></comment></comment></comment><comment><USER7> " _I've never used multicasting in a real-world application but will be keeping my eyes open for an opportunity_ ". Don't. Seriously, just don't do it. I personally know of outages directly attributed to multicast that have cost more than your $widget will ever make.

 _But_ , you say, _I've got the textbook case of media broadcast!_ Yeah, still probably not worth it. Check out UDP broadcast, or tiered distribution, or service and peer discovery. There's another way to do what you want.

 _No way! I know all about multicast forwarding, and every node really does need all of these packets_ Really? You're going to build reliable delivery at the application layer? And deliver yet _more_ mcast to _every_ node. And you won't have contention problems, across your entire domain, for the limited byte & namespace resources? And it won't be a problem when every packet _must_ be routed to every TOR? Because you _will_ have heterogenous hosts in each rack subscribed to every available group.

So, really, don't do it. It looks cool. It looks efficient. It looks simple. It's not. In grown up land it's just not worth it.</comment>