The sleeping beauty paradox - <AUTHOR> http://stats.stackexchange.com/questions/41208/the-sleeping-beauty-paradox <comment><USER2> I'm having trouble finding the paradox here. As with many probability puzzles, the problem seems to be a hidden conditional in the probabilities.

There's no change in belief happening, only two different beliefs. First is "1/2 of the times it is flipped, the coin will be heads". Seconds is "1/3 of the times I am awakened, the coin will be heads". The coin flip is fair, but the decision to ask the question is biased.

This is extremely simple to demonstrate by resorting to the absurd case. If we change the awakening ratio away from 1-2, the absurdity of saying "1/2" becomes increasingly clear. At 1-9, tails will be the correct guess 90% of the time the question is asked. At 0-1, heads isn't even a possible outcome on awakening.

<comment><USER3> Both answers are valid because the question is ambiguous. Asking "what is your belief" doesn't work because there are multiple ways to interpret that. You can clarify such situations by putting them in a game. Probabilities are about how much you would bet on it.

Game 1: You get $10 every time you guess correctly. Best strategy: Guess tails because if it's correct you get $20. If you guess heads correct you get only $10. If you got $3 for guessing tails correctly and $6 for guessing heads correctly then it would not matter what strategy you used.

Game 2: If you guess correctly then you get $10 by the end of the experiment. Best strategy: it doesn't matter what you guess, if you guess tails correctly you get the $10, and if you guess heads correctly you also get $10.

Thirders think the question is like game 1: every time they guess correctly they win correctness points. Halfers think the question is like game 2: they either guess correctly or they don't; you don't get additional correctness points by guessing right twice.

<comment><USER4> > Game 2: If you guess correctly then you get $10 by the end of the > experiment.

The question is clear you get a reward each time you awaken, not at the end of the game.

The reward is correctness (Humans like being correct = reward, else things like 'should believe' becomes meaningless hence the question becomes meaningless Q.E.D. it's not meaningless and correctness is a reward)

"When you are awakened, to what degree should you believe that the outcome of the coin toss was Heads?"

<comment><USER2> This fits with my understanding of what's happening here. The SO discussion is a bit unclear as you go down the page, but the initial statement of problem up top clearly claims that you're questioned each time you awaken.

I think you're quite right to point out that _being correct_ is the only fair heuristic for this question. Several of the defenses of a 'halfer' belief amount to "you ought to believe this so that your beliefs obey this type of decision theory". Actively believing something with a (reliably) worse payout to conform to a rule about belief seems like a terrible form of epistemology.

On a related note, are you familiar with Newcomb's Paradox and the LessWrong debates over it? They get to a similar idea of "correctness above all".

</comment></comment></comment></comment><comment><USER5> Can someone explain the half position clearly? I don't understand how anyone could think half is the correct answer.

Let me frame the question a different way. You are one of three volunteers in separate rooms. I flip a coin and if it's heads I ask one volunteer (at random) to guess the outcome. If I flip tails I ask two of the volunteers (again, at random) to guess the outcome.

You know the rules I will follow, but you cannot tell if anyone else has been asked before you. I open the door and ask you to guess the outcome of the flip. What do you guess?

<comment><USER6> The fact is, there _aren 't_ three volunteers, there's only one. Upon awakening, she has no information she didn't have when she went to sleep, which at first seems to be an unassailable argument in favor of the "halfers."

To me, the problem with the "no new information" argument is that there's another popular paradox in which it also seems to apply, but fails spectacularly. In the Monty Hall paradox ([https://en.wikipedia.org/wiki/Monty_Hall_problem](https://en.wikipedia.org/wiki/Monty_Hall_problem)), you know in advance that the host is going to open a door at random and offer you a chance to change your initial guess. You're aware that the host knows what's behind the doors. You know that no matter what door you pick, one of the remaining ones has a goat behind it. And you know that the omniscient host will pick that door. So what new information do you gain when the host does what you knew he was going to do?

One way to resolve the Monty Hall paradox is to rephrase it such that there are a million doors and the host opens all of the remaining ones except one. Of course it makes sense to switch doors in that scenario, since you knew that the host would avoid opening your initially-chosen door as well as the one with the car behind it. Your initial door has 1:1000000 odds of winning, while the only other closed door has odds of 1/2.

So if you could find a way to transform the Sleeping Beauty problem into a Monty Hall problem, that could be a good way to settle the argument in favor of the "thirders."

Or, if with some logical sleight-of-hand, you could show that SB is _not_ isomorphic to MH, that could potentially be used to strengthen the no-new- information argument made by the "halfer" side. I'm leaning that way, because SB does not know upon awakening, and will not remember, whether the experiment will result in her being awakened twice. _For all she knows, she 's playing the same Monty Hall game for the second time._ It's this lack of an unbroken timeline of conscious awareness that settles the question in favor of the halfers.

To answer the thirders' rebuttal that SB would lose money if she were gambling on the coin toss with any odds other than 1:3, I'd say that's a completely different experiment. We aren't being asked to speculate on the set of events behind multiple awakenings, just one in isolation. The lack-of-new-information argument carries the day. Any arguments that involve repetition, clones, or gambling fail because they are responding to a different question.

TL,DR: Don't gamble if the game involves erasing the players' memories. You will lose a lot of money in a hurry, even if your strategy is mathematically optimal.

<comment><USER7> Here's an amplification that might clarify it. If you flip heads, I'll wake you up zero times. If you flip tails, I'll wake you up once. Now what's the probability that you flipped tails. 100%, right? Why? The coin still has a 50% chance of giving either heads or tails.

Here's another -- if you flip heads, I'll wake you up once. If you flip tails, I'll wake you up a million times. When I wake you up, is it more likely that you flipped tails or heads, remembering that you don't know which day it is.

You are right, by the way, that there is no new information -- the tendency to answer "50%" the night before is the logical error. You are conflating the odds of flipping heads or tails with the odds of WHETHER you flipped heads or tails in light of the known outcome (which is not 1:1 with flipping heads or tails).

Also, if you believe in statistics, the right answer in the continuous case (infinite repeats) is also the right answer in the singular case (one repeat). Your point about "there aren't three volunteers, only one" is fallacious.

<comment><USER6> _Here 's an amplification that might clarify it. If you flip heads, I'll wake you up zero times. If you flip tails, I'll wake you up once. Now what's the probability that you flipped tails. 100%, right? Why? The coin still has a 50% chance of giving either heads or tails._

I do like that, it's a strong argument. But it still relies on monkeying with the participant's awareness in a way that is likely to (or in this case, _will_ ) keep them from making the right decision over time. You use the term "known outcome," but there isn't a known outcome if you're dead or asleep forever.

 _Your point about "there aren't three volunteers, only one" is fallacious._

But so is treating it as any other problem (like gambling) that only converges on an answer after multiple trials. The strength of your argument is that it doesn't rely on answering a different question, just changing a parameter in the question that _was_ asked. But it's an awfully important parameter. Implicit in the question is the premise that you will be alive/aware at some point in the future, so that you can be asked what you think.

Edit: another way to rebut your particular argument is by sticking with the original terms of the problem, except that if the coin lands on heads, they shoot you after you answer. That doesn't help you answer the question.

<comment><USER7> I think you're starting to grasp it. The key here is that if you are dead or asleep forever, _then you are not waking up to answer the question_. Therefore, the simple fact that you are waking up brings new information to the situation -- you know for sure that you didn't flip heads.

<comment><USER8> But in the original question, you were already guaranteed to wake up, so how does it give you any information?

</comment></comment></comment></comment></comment></comment><comment><USER9> I don't see the problem in their problem:

> Whenever SB awakens, she has learned absolutely nothing she did not know > Sunday night. What rational argument can she give, then, for stating that > her belief in heads is now one-third and not one-half?

The argument that she can give is clear: she _might_ have learned something, but the memory was taken from her. And she knew that they would take the memory from her. So yes, she hasn't learned anything new, but that's a cop- out—the problem explicitly prevents it.

I mean, from that perspective, she doesn't even need to go to sleep! They could ask her, "when you wake up, how likely will you think that the coin was heads?" and get the same (correct) response of 1/3\. That result is not based on her "learning new information" (since the situation forbids it), it's based purely on the situation as described.

<comment><USER10> > They could ask her, "when you wake up, how likely will you think that the > coin was heads?" and get the same (correct) response of 1/3.

Exactly. Let's stretch the example to the extreme, if you get heads you get woken once, if you get tails you get woken 1 million times. Now say you run this experiment 10 times and you happen to get 5 heads and 5 tails. You'd be woken up 5 million and 5 times. And with each wakening, the chance of the coin having been heads isn't 50%, if you'd say and guessed it was heads every time you wouldn't get half of them right, you'd be statistically wrong about 5 million times out of the 5m and 5 times. The correct answer is 1 in a million, and if you'd guessed tails on every awakening instead you'd be wrong on average only once in a million.

It's this chance to be correct or incorrect in your answer when waking that would inform the question that was posed 'When you are awakened, to what degree should you believe that the outcome of the coin toss was Heads', which then would be 1/3.

<comment><USER11> First of all, how often you're correct doesn't matter; say the tails option wasn't "you'll be woken up a million times", but instead "you'll be asked _the same stupid question_ a million times" (and have to answer as if you'd forgotten the previous answer). _Of course_ you'll be wrong more often in the tails situation.

Second, the experiment isn't run 10 times. It's run once. A single coin flip. With a multitude of flips, you've got no idea where you are in the sequence so it pushes your averages toward the 1:1000000. But a single coin flip is a single coin flip, 50/50.

</comment></comment></comment><comment><USER12> Here is a surefire way to win the lottery.

Start by picking numbers. Your chances of winning naturally are very small, so I will make an arrangement with you. You go to sleep before the winning numbers are read. Afterwards, if you have won, I will wake you up N times, administering our trusty forget potion. But if you have not won, I will wake you up only once.

As we have established in this thread, by increasing N, your chances of having guessed the lotto numbers correctly upon awakening approach 100%.

I wake you up, you apply Bayes' Theorem, and then rejoice, for you almost certainly have won the lottery!

</comment><comment><USER13> "[…] to what degree should you believe that the outcome of the coin toss was Heads?" is a terribly unrigorous way to phrase this question. I suspect it's where all the confusion sets in.

Are we adjusting the natural prior of a coin toss based on information we now have? We have no information; 50%.

Are you placing a bet each time you are awake? You get to bet _twice_ if the coin comes up Tails; 2:1 (33%) odds against Heads balances the tables.

Are we judging how often we'd be correct if we guessed Heads every time we were awoken? Depends on the number of trials. With only 1 trial; 50%. With 2 trials; 42%. With infinite trials; 33%.

Nothing begets a paradox like an ill-posed question.

<comment><USER14> >We have no information

We do, we know that we are now in the experiment. In the case where you don't wake up on heads at all, have you learned new information upon waking? If yes, why don't you learn something anytime the relative probabilities differ?

<comment><USER13> That's not new information. You know that you will be in the experiment before the coin toss. Information does not flow acausally.

To contrast with Monty Hall, after the MC opens the first door, you _do_ have new information: you glean information from the MC's choice, which he made based on his knowledge of where the prize is.

In this problem, the researchers take no action visible to you after the coin flip, and your memory is wiped before each new observation you can make. So your knowledge about the flip's outcome is exactly the same after it occurs as before: 50% chance.

<comment><USER14> If that doesn't count as new information, does waking up if you were to only wake on tails count as new information?

If yes, what's the justification for distinguishing the two?

What happens if you are told it's your first awakening as soon as you get up? Bayes theorem would imply you can't think the chances of heads stay the same before and after hearing this, so at least one must not be 50%.

<comment><USER13> I might be misunderstanding your conditions, but I would say no, waking up only on tails would not count, unless of course you got to make your choice _after_ the researcher indicates they're about to put you back to sleep. Then you obviously know that the coin flip was tails! But in any case where you have just awoken after having had your memory wiped, and you have not been told anything by the researcher, you have been given no new info.

I think, if you are told it's your first awakening, then you still must assume 50% heads or tails: in both cases, you will always have a first awakening, so there is no new info there. _However_ , since you will _not_ be told this in your second awakening, if that occurs, you know immediately the coin must have come up tails.

<comment><USER14> >I think, if you are told it's your first awakening, then you still must assume 50% heads or tails: in both cases, you will always have a first awakening, so there is no new info there.

How is this not a direct violation of Bayes theorem? The probability of learning that it is the first awakening differs based on what the coin flip was, so it requires an update.

<comment><USER13> Once you know it is the first awakening, the probability of it being the first awakening is 100%.

<comment><USER14> When you wake up, you don't know which awakening it is. You claim the probability of heads is 50%.

Now, you are told it is the first awakening. The probability of learning that if heads is twice as much as the probability of learning that if tails, so your Bayes factor is 2:1. You therefore cannot still believe that the probability of heads is 50%.

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER15> Maybe it's really an argument about this:

Upon awakening:

Halfer:

        P(monday,heads)=0,5
        P(monday,tails)=0,25
        P(tuesday,tails)=0,25

Thirder:

        P(monday,heads)=0,33
        P(monday,tails)=0,33
        P(tuesday,tails)=0,33

<comment><USER15> I think it boils down to the thirder position.

P(monday,heads)=0,33 since P(heads)=0,5 and P(monday)=0,67.

This is because we are sampling awakenings, not coin tosses or beauties.

It's like betting on a coin toss, but with a side twist that the bet is evaluated twice (no new toss) when the coin is tails. Hence a majority of evaluations will be on tails:

      Guess, Coin, Profit
      H,     H,    +1
      H,     T,    -2
      T,     H,    -1
      T,     T,    +2

Analysis for betting heads: average is +1 + -2 = -1 Betting tails: average is -1 + +2 = +1.

I'd bet tails!

</comment></comment><comment><USER16> A similar problem is God's Coin Toss as described in Scott Aaronson's excellent lecture series (and book) "Quantum Computing Since Democritus":

[http://www.scottaaronson.com/democritus/lec17.html](http://www.scottaaronson.com/democritus/lec17.html)

</comment><comment><USER17> Not a paradox...here is a proof that it is 1/3

Let P(T) = probability that coin landed on tails, P(H) = probability that coin landed on heads.

Let "1st" denote the event that it is the first time you are awaken, "2nd" the second time.

Note that P(T|1st) = 1/2 (if you were told that this is the first time you were woken up, it's equally likely that the coin landed heads or tails). And of course, P(T|2nd) = 1

By the definition of conditional probability, 1/2 = P(T|1st) = P(1st|T) _P(T) /P(1st) = (1/2)_P(T)/P(1st) Hence P(T) = P(1st) = P(T) _1 /2 + P(H) = P(T)_1/2+(1-P(T)) = 1 - P(T)/2 -> P(T) = 2/3

</comment><comment><USER11> Both are right: the two camps posit completely different things.

Halvers stipulate a single experiment. Thirders stipulate infinite experiments.

It is pretty straightforward math to show these are not inconsistent, and there are even options in between. [https://stats.stackexchange.com/questions/41208/the- sleeping...](https://stats.stackexchange.com/questions/41208/the-sleeping- beauty-paradox/169582#169582)

</comment><comment><USER18> From my understanding, the answer is 1/2.

Let us assert that the probability of the coin flip being heads is 1/2.

Now, you have awoken. Regardless of if you've awoken to the Heads flip, or the first time to the Tails flip, or the second time to the Tails flip, the original flip's chance was still 1/2.

The possible misunderstanding comes from the fact that you will awake TWICE to Tails, which is more than to Heads! But the thing is this is irrelevant to the question, because you don't know whether this is the first or the second time, and you only need to wonder whether the original flip (recall it is probability 1/2) was heads or not. Potentially you could think that you'd be "wrong" more often, but we are only looking at one specific instance of you waking up in isolation, for which you have no additional information.

For example, consider waking up 1000 times if the flip is tails. Upon waking up, do you think the probability heads becomes 1/1001? I think regardless of waking up the first time or the 1000th time, you have no more information so it might as well have been the first time, and hence the probability is 1/2.

<comment><USER19> > ...Upon waking up, do you think the probability heads becomes 1/1001?

Of course, do you really think otherwise? If I promised to put a pound in your moneybox every time you correctly guessed the coin state on each awakening, would you really fall to sleep confident in a 50/50 guess strategy in your 1000 awakenings to 1 scenario?

<comment><USER20> the betting argument is not the same as what is being discussed.

to a halver, the likelihood of heads and tails are still each 1/2, but the expected winnings of betting tails would of course be larger.

it would be like saying i'll flip a coin, and if you guess correctly that it's tails i'll give you a million dollars. obviously i will guess that it's tails, even though i still believe each outcome is equally likely.

</comment></comment></comment><comment><USER21> It seems to me that the paradox/confusion here comes from asking someone to consider a distribution over a bound variable - i.e. you are asked to examine the odds of X happening in a situation where there are already side effects of whether or not X happened.

In this sense, it reminds me of the puzzle where a man gives you a choice between two envelopes, one of which is specified to contain twice as much money as the other, with the paradox centering on a bystander's argument that you should then switch envelopes, since the other one must have either half or twice your value, giving you a 1.25x higher expected value for switching.

As I understand it, in both cases the "traditional" solution to the problem is to recognize that probability doesn't work that way, and you can't consider distributions over bound variables, but the more interesting solution is to rephrase things in Bayesian terms, in which case the analysis is reasonably straightforward.

I'm a dabbler though; experts please tell me if I'm spouting gibberish.

</comment><comment><USER22> You're flipping a fair coin again and again. Every time you flip heads, you add 1 black ball to a (initially empty) bag. Every time you flip tails, you add 2 red balls to the same bag bag.

After a large number of flips, you pick a ball randomly from the bag.

What are the odds that the ball was added when a heads was flipped?

What are the odds that the ball is black?

<comment><USER12> The question specified one coin flip. In your thought experiment, after one flip, the answer to both your questions is 50%.

</comment></comment><comment><USER23> I'm a layman in probability but isn't it the same thing as the Inspection paradox? [http://allendowney.blogspot.be/2015/08/the-inspection- parado...](http://allendowney.blogspot.be/2015/08/the-inspection-paradox-is- everywhere.html)

</comment><comment><USER24> I remember reading rec.puzzles occasionally in the day when the Sleeping Beauty question was first posed. Coming back after not reading the group was for a couple of weeks was incredibly confused because it was full of minor variants of this single question constructed by people to support their position. I'd not only missed the original question and was thus lacking the context completely, but also had missed the megathread that followed and didn't understand the political undercurrents which would have been obvious if I'd only known who was halfer and who a thirder. It was just crazy.

Here's a great account of how it unfolded: [http://www.maproom.co.uk/sb.html](http://www.maproom.co.uk/sb.html)

</comment><comment><USER25> This reminds me of the Monty Hall problem, but in reverse - you were playing the Monty Hall game and just won the car! You forgot whether or not you switched doors during the second step - what is the probability you switched doors?

<comment><USER2> There's actually a strong analogy to an extended Monty Hall here. Specifically:

1\. Monty offers the challenge, and I pick door B.

2\. Monty opens door C, showing a goat.

3\. Monty asks if I want to switch. My odds of winning are now P(A) = 2/3, P(B) = 1/3.

4\. My mom flips on the TV to see me play, but has missed my answers and only sees the state of the doors. What are her odds of guessing right?

Result: my mom's odds of winning are 1/2, even though the odds of a given door winning are not. There's a bias between the two doors, but her perspective is neutral - she's guessing which door has better odds, and that guess is unbiased.

As you say, this question is the reverse: the odds on the coin flip are unbiased, but my odds of being asked the question are biased towards one of the two outcomes.

<comment><USER6> See my other post; I actually think that a Monty Hall comparison argues in favor of an unbiased 1:2 guess, because of how the terms of the two problems differ.

In the SB question, your odds of being asked the question are 1:1. You just don't know how many times you'll be asked. You didn't know the night before (and neither did the researchers), and you still don't know, even though the researchers now do.

In the MH game, you give the host some new information when you make your initial choice. He already knew what door _not_ to open, but now he knows what door he _must_ open, and the rules require him to communicate that to you. That's when you receive the new information (as you point out with the example of your mom walking into the room).

In the SB problem, you don't get any new information before the question is asked, including whether or not you're going to be put back to sleep. So the only answer you can rationally give is 1:2.

If the researchers used a d20 instead of a coin to determine how many times to wake you up, you could safely guess that any given awakening wasn't your first or your last. But you still can't give any answer about the number on the die, other than a random guess from 1-20. You need to store some information for later recall, and they're not letting you do that.

</comment></comment></comment><comment><USER26> I'm not sure this is a paradox. There are 2 expected outcomes. All the added outcomes rely on the experimenter to disrespect the set rules.

This is a conditional probability with a hard to predict condition (ie. human factor) portrayed as a non-conditional probability. This looks more like a bad representation of a problem rather than a paradox.

This reminds me of my youth. Regardless of the project I was trying to accomplish, as soon as my little brother got involved, all bets where off. He was a hard to predict little bugger.

</comment><comment><USER27> Even if you get awakened 99 times with Tails, you have equal probability going down the Heads (1 awakening) or Tails (1/99 awakenings) paths.

So if you awaken with no knowledge of other awakenings, you are equally likely to be on either path, with the coin being Heads or Tails.

You are NOT equally likely to guess that your awakening was due to Heads or Tails however, and that's the paradox.

<comment><USER14> This is basically just asserting SSA.

One problem with the halfer claim is that if you learn it is the first awakening, you then place much more probability on it landing heads (basic Bayes theorem application), even when the coin is yet to be flipped. How would you resolve that?

</comment></comment><comment><USER28> I'm not sure I understand this given the way the question is posed.

We're doing a single experiment, and I am put to sleep without remembering either once or twice, and then awaken (potentially a third time) after that?

Or could this keep going indefinitely until heads comes up?

And am I guessing each time I'm woken, or only after the final time?

</comment><comment><USER29> How do the researchers get you back to sleep for the second (tails) awakening?

You're woken once or twice and given the potion. Or you're woken and given the potion each time. This riddle wants it both ways, and that is part of the problem with it.

<comment><USER14> You're only given the potion right before going to sleep, after you need to state your probability estimates.</comment></comment>


Is Cloudflare a honey pot? - <AUTHOR> http://www.crimeflare.com/honeypot.html <comment><USER2> Going by their homepage, the site that posted this doesn't like anybody. Also, they make a huge song and dance about people "hiding" behind cloudflare, however:

 _Registry Registrant ID:

Registrant Name: WHOISGUARD PROTECTED

Registrant Organization: WHOISGUARD, INC._

yeah, whatever...

The same server also hosts a site with this fine page: [http://www.namebase.net/books52.html](http://www.namebase.net/books52.html) suggesting AIDS is a bio weapon engineered by the USA. Given that they appear to have been designed by the same person with unlimited access to MSPaint, version Windows 3.1, I think it is safe to assume this is by the same people.

</comment><comment><USER3> No.

Even if the original idea (which btw, the origin story was shared on TechCrunch when they launched, was maybe even on their about page, etc.) was from this honeypot project, CloudFlare is a different beast. Moreover, there's now the company-wide "we'd all have to be in on it" perspective. If you read through the posts from folks like jgrahamc and others, you'd hopefully conclude that selling visitor data would be much less interesting than their actual business.

<comment><USER4> Still, begs the question: what value do they get from their "Free" customers? Is it simply a freemium model based on getting conversions OR do they extract value from front-ending those smaller sites? Seems like the latter for sure... but that doesn't make it a honeypot.

<comment><USER5> Cloudflare makes money by charging our customers for the service we provide. Turns out that lots of people pay us for that service and that money is much greater than the cost of running the service.

Here's the important thing about those FREE customers: many of them turn into high-paying customers later. For example, it is very common for CIO/CTO at $BIG_CORP to quietly test their personal blog on a Cloudflare FREE plan and we have no idea they are doing it. Later CIO/CTO uses that experience and decides to spend $BIG_DOLLAR from $BIG_CORP with Cloudflare.

</comment></comment></comment><comment><USER6> There's a CloudFlare engineer who posts prolifically here on HN; he's denied that they sell data of any kind numerous times. I think it's safe to take them at their word without proof otherwise? [https://news.ycombinator.com/item?id=12830120](https://news.ycombinator.com/item?id=12830120)

<comment><USER7> You think it's safe to take the word of an anonymous stranger on the internet?

<comment><USER8> Yes.

There is nothing particularly dangerous about accepting claims from strangers on the internet at face value. I don't use their service, so I'm not going to be harmed by anything he says if he is lying or if he is telling the truth. If I decide later to use their service or if he says something that seems false or misleading when taken at face value, I can adjust my level of skepticism accordingly.

</comment></comment></comment><comment><USER9> It's definitely an organizational "SPoF" a-la Lavabit in that govts can lean on it, attempt to squash it, try to hack it, etc., whereas distributed solutions like i2p and BitTorrent are harder to strangle.</comment>


Revolutionary Aluminum Process Eliminates Emissions, Produces Oxygen - <AUTHOR> https://www.engineering.com/AdvancedManufacturing/ArticleID/16941/Revolutionary-Aluminum-Process-Eliminates-Emissions-Produces-Oxygen.aspx <comment><USER2> The last line makes me sad "proprietary process". I was curious about the actual chemistry.

<comment><USER3> Here is the paper about it(not the process specifically, but it describes what it will does in principle): [https://www.researchgate.net/publication/262148554_The_Alumi...](https://www.researchgate.net/publication/262148554_The_Aluminum_Smelting_Process_and_Innovative_Alternative_Technologies)

<comment><USER4> That paper shows the chemical formula emits CO2. Are you sure this is the same process?

<comment><USER3> Relevant text from the paper: We see immediately that this reaction is different from Equa- tion 1. Here, oxygen is formed at the anode, which environmentally is a highly favorable gas, compared with CO2. The dream would of course be to have anodes that lasted as long as the cell life, which now may be up to 5 years or longer. Anode changes would then not be necessary after the cell has been started. Nevertheless, it is a chemical fact that all materials have a finite solubility in the very corrosive cryolitic melts at about 960◦C, so a totally inert anode will probably never be found for use in these electrolytes. Thus, what we really are looking for is a slowly consumable anode. But how slow a consumption rate can we tolerate? The potential inert anode material must have low solubility and low reactivity in the electrolyte and also show good chemical re- sistance against the anodically produced hot oxygen gas. In addition, the anode material should be physically stable at the operating tem- perature, mechanically robust and resistant to thermal shock. There will be extreme requirements for keeping the wear rates of these anodes low. A wear rate of the order of 10 mm/y may perhaps be sufficient, but lower values would certainly be beneficial. There are two main challenges in the development of inert anode materials. In addition to the requirement that the anode ma- terial should survive sufficiently long in the electrolyte, the metal produced must be of adequate purity. The impurity metal content in the aluminum can indeed be very significant for the customers, and the need for making pure aluminum will become more stringent in coming years. The corrosion products, caused by the dissolution of the anode material into the electrolyte, predominantly will end up in the metal phase and thereby contaminate the aluminum produced. Hence, the anode corrosion should be low enough to give impu- rity contents corresponding to the present specifications for smelter grade aluminum. There are three principal potential advantages in favor of de- veloping a new cell technology with inert anodes: 1\. Cost reduction. All costs directly associated with the consumable carbon anode will then be eliminated, including the capital saving and raw materials costs by eliminating the need for the carbon anode fabrication, baking, and also the anode rodding plant. These cost savings may be significant. It has been indicated that there might be 25% to 30% lower capital costs for a new potline with inert anode cell technology.3 2\. Environmental friendliness. Inert anodes would eliminate all greenhouse gas generation and emissions from the electrolysis cells. Smelters would no longer generate CO2, carbon monoxide, or perfluorocarbon gases (CF4and C2F6), because carbon would no longer be used as anode material. Carbon residues (butts) will of course disappear. In addition, the fluoride and dust emissions during anode change will also be eliminated. 3\. Improved occupational health issues. Inert anodes would reduce the work practices associated with the present prebaked carbon anode change. The frequency of anode changes will certainly be drastically reduced with inert anodes. Working conditions in the potrooms would also be improved by avoiding all anode effects. The outlook of the primary aluminum industry may be sum- marized as follows: This is now a mature industry, which presently (2013) suffers severely from low aluminum prices and a very chal- lenging market situation. Technologically, the present aluminum production process can be a close-to-zero greenhouse gas producer. The first step, which is actually ongoing, is to focus on lower specific energy consumption, and also to eliminate the occurrence of anode effects. Furthermore, it is possible to reduce the inherent production of CO2by reducing the net carbon anode consumption, although this reduction can only be perhaps 10% or even less with the existing carbon anode tech- nology. Here, an inert anode, if such a material can be found and developed for use in industrial aluminum production, would repre- sent a remarkable technological breakthrough, because then oxygen is formed at the anodes instead of CO2

</comment></comment></comment></comment><comment><USER5> Of course it produces oxygen - aluminum processing is in large part reducing aluminium oxides.

Given the scant data provided it is unclear if their technique results in fewer additional airborne pollutants mixed with the oxygen which might be nice

</comment><comment><USER6> Does this require less energy input?</comment>


Ask HN: Is there a bias against hackers from 'name-brand' colleges? - <AUTHOR>

Hackers are some of the most meritocratic and egalitarian people I know, but sometimes I sense a sort of backlash against our peers who went to so-called 'name-brand' colleges by those, like the vast majority of us, who went to non-luxury colleges.  Do you see this as well in your workplace?  If so, please discuss reasons you think this might be happening.  How much differently do you treat people based on where they went to college?  Thanks! <comment><USER2> There's jealousy sometimes, but ultimately if you've got skill commensurate (or better) with the name brand of your degree, it's not a problem at all. Most people are cool. If you're an arrogant ass, you'll get treated like one. If you got hired by management based on your school, but you can't code very well, people will look down on you.

Actually, the broader backlash by far seems to be from some self-taught hackers against people who've gone to school for computer science. There seems to be this idea out there that a computer science program is worthless for becoming a good hacker. For crappy programs, this is true. For great ones, it couldn't be further from the truth.

Anyway, do expect some people to try to test you though and embarrass you if they can. Of course, those people probably would have tried no matter where you went to school.

<comment><AUTHOR> thanks for the quick reply! i'm curious about your statement about "skill commensurate with the name brand of your degree" ... does that imply that certain people are held to a higher standard due to where they went to college? that seems unfair both to those people (who have unreasonably elevated expectations) and to everyone else (who have lowered expectations since they don't have a name-brand diploma). if 2 people are in the same position at the same company receiving the same pay (working as peers), shouldn't others expect something similar from them regardless of their degrees?

<comment><USER3> Is it really unfair to hold someone to a higher standard because they went to a 'good' school? I think part of the way we estimate future performance is by examining past performance, and performing well at a name-brand school should indicate ability to perform well at tasks for which their education prepared them.

On the other hand, doing well at a non-name-brand school doesn't mean another person can't perform well, it just means that you can't predict quite as easily how well they'll do.

If you give an easy exam and everyone scores 90% or better you don't know much more about the person who scored 100% than you do about the person who scored 90%. If, on the other hand, you give an extremely difficult exam that results in a curve with the 90% cut-off at 80% and the 10% cut-off at 20% you know much more about the abilities of those who did well compared to the abilities of those who did poorly. I think people tend to view a name-brand college as a the very tough exam and a non-name-brand college as the easy exam. Whether or not this is a safe assumption is another question.

<comment><USER2> _Is it really unfair to hold someone to a higher standard because they went to a 'good' school? I think part of the way we estimate future performance is by examining past performance, and performing well at a name-brand school should indicate ability to perform well at tasks for which their education prepared them. On the other hand, doing well at a non-name-brand school doesn't mean another person can't perform well, it just means that you can't predict quite as easily how well they'll do._

I agree with this, which is why I put "unfairness" in quotes in my other response. There's a certain political correctness that makes people uneasy about comparing two candidates based on the schools they went to. The fact is, the rigor of training for the same degree varies wildly depending on the school you attended.

If you're comparing two seemingly equivalent unknowns who've got no body of work other than a degree, I think it makes perfect sense to bias towards the person who completed the better program.

<comment><USER3> I should have been more clear about what I was responding to - this commend by rdr:

"does that imply that certain people are held to a higher standard due to where they went to college? that seems unfair both to those people (who have unreasonably elevated expectations) and to everyone else (who have lowered expectations since they don't have a name-brand diploma)."

I agreed with both your original comment and the follow-up. The question of fairness got me thinking, though, and I wanted to present one way of thinking about it.

</comment></comment></comment></comment></comment><comment><USER4> I'm more worried whether there's a bias against hackers from non-name-brand colleges, especially in the startup community.

<comment><AUTHOR> really? isn't the startup community supposed to be more anti-establishment and not worry about paper credentials as much as, say, a large corporation or government organization?

</comment></comment><comment><USER5> Hopefully I know enough about a co-worker's skills to form a good opinion of them before I find out what college they went to. If you bring it up in our first conversation, I'm going to wonder why.

On the other hand, if you went to grad school, research is such a small world that this kind of thing comes up more often - I might ask who your advisor was, etc, to find out whether we have friends in common. It's less about skills.

</comment><comment><USER6> It's no coincidence that startups start around universities, because that's where smart people meet. It's not what people learn in classes at MIT and Stanford that has made technology companies spring up around them. They could sing campfire songs in the classes so long as admissions worked the same. -Paul Graham. "How to Start a Startup," March 2005.

</comment><comment><USER7> A brand name helps in getting job interviews and it helps open doors. Backlash is very uncommon, unless you are a jerk.

</comment><comment><USER8> It's a good question, but tough to answer because its impossible to generalize the behavior of "hackers".

That said, I have heard of backlash against 'name-brand' colleges at a startup, but it was, interestingly, not by hackers but by business dev. people.

I think at the end of the day, you're a jerk if you judge a person by their college. And you're a jerk if you think going to a good college actually means you're inherently more capable than other folks.

</comment><comment><USER9> "Hackers are some of the most meritocratic and egalitarian people I know..."

Maybe you need to meet some new hackers.

I have never seen this. Ever.

30 years. 90 companies. 1,000,000 lines of code.

Maybe it's just because people who know me know better than to bother with details instead of issues.

Your "pedigree" is a detail. Your work is an issue. Don't waste your time with those who don't know the difference.

<comment><USER10> Your reaction to this suggests to me that you may have mistaken what meritocratic and egalitarian mean. People with these qualities do not usually care about things such as ones "pedigree", thus the GP's confusion that hackers look down upon people who've attended "name-brand" universities.

If not, please elaborate on your post as I do not understand how you in 30 years can not have met hackers with these qualities.

<http://dictionary.reference.com/browse/meritocratic> <http://dictionary.reference.com/browse/egalitarian>

<comment><USER9> Sorry. The part of OP's post I have never seen was that "backlash" part, not the "meritocratic and egalitarian" part. I see now how that could have been misinterpreted because my manual string extraction was off by 62 characters.

But thanks smacking me with 2 dictionary links. That oughta fix it.

<comment><USER10> No offense was intended, I simply did not parse your reaction to what you quoted.</comment></comment></comment></comment>


One Nation, Tracked - <AUTHOR> Http://nytimes.com/tracked <comment><USER2> I am surprised that this article didn't attract discussion on HN. It would be useful if NYT can just straight up publish which apps were giving those out. That would make people instantly uninstall them and probably not touch them again for a long time.

<comment><USER3> It's been posted and attacted some attention:

[https://news.ycombinator.com/item?id=21833718](https://news.ycombinator.com/item?id=21833718)</comment></comment>


Court Rules That Politicians Blocking Followers Violates Free Speech - <AUTHOR> http://nymag.com/selectall/2017/07/judge-politicians-blocking-followers-violates-free-speech.html <comment><USER2> This is irrational.

Not that I expect the courts to be rational anymore.

Anyone should be able to block (and unblock) anyone they like on social media.

</comment><comment><USER3> Next: A voter's failure to open franked mailers violates the Congressmember's free speech.</comment>


Show HN: BankLocal – Find local banks and invest in growing your community - <AUTHOR> http://banklocal.info

<comment><USER2> Hi,

putting aside the debate over free market theory for the moment, as regards the banking industry the evidence is very clear and compelling: smaller sized banks and credit unions do in fact lend a greater portion of their assets to small businesses. This mainly has to do with the business structure of large vs. small banking institutions. To quote the FDIC's 2012 Community Banking Study:

"Community banks tend to be relationship lenders, characterized by local ownership, local control, and local decision making. By carrying out the traditional banking functions of lending and deposit gathering on a local scale, community banks foster economic growth and help to ensure that the financial resources of the local community are put to work on its behalf. Community banks have always been inextricably connected to entrepreneurship. As of 2011, they held 14 percent of banking industry assets, but 46 percent of the industry's small loans to farms and businesses."

Analysis of our own data is even more telling: BankLocal data as of 12/31/13 shows that the nation's four largest banks, JP Morgan Chase, Bank of America, Citibank and Wells Fargo (collectively known as the Big-Four) only loaned 1.9% of their combined assets to small businesses compared to 10.6% for small and medium size banks.

If small businesses and the Main St. economy matter to you, then so should Local Banking.

<comment><USER3> > _putting aside the debate over free market theory for the moment..._

But this is the central point, whether a person is interested in investing locally, or investing in small businesses. I already addressed the issue of investing locally in my top level comment.

> _If small businesses and the Main St. economy matter to you, then so should > Local Banking._

Free market theory says that there is no reason to prefer small vs large businesses. Which ever is most efficient will win in the market place, and will produce the most total welfare. And if income distribution is a concern, taxation and redistribution is a better way to address this than funding small businesses.

The term _Main St. economy_ is misleading, because both small and large businesses contribute to the economy in exactly the same way. There is no way in which big businesses don't affect or benefit ordinary people.

<comment><USER4> "Which ever is most efficient"

If I care about the most efficient way to make sure money stays local to my region, dealing with institutions that have a habit of keeping money in a particular region seems the best way to ensure that happens.

<comment><USER5> Efficient is a technical term from economics. It refers to whatever maximizes total welfare. Total welfare is also a technical term, and is roughly approximated by GDP.

You don't have to believe efficiency is an important goal (although my post was arguing that it is). But please let us have this word. Arguments should be had on the basis of refuting peoples ideas, not depriving them of the use of any word with a positive connotation.

</comment></comment></comment></comment><comment><USER3> While I guess it's good to provide people with information that they want, I disagree with the premise that _Local banks and credit unions work within established localities and reinvest depositors ' money into local businesses, farms, and individuals. To put it simply, they often use your money more responsibly than large megabanks, and your community benefits._

Every business is located somewhere. Why would it be better for a person to invest in projects located near themselves, than far away? From the way they phrase it, you'd think that megabanks [sic] throw the money into a black hole, or otherwise use it in some manner other than investing in businesses (which again, must be located somewhere).

The movement to buy/invest locally goes against all of economic theory. Artificial barriers to trade (such as a choice to buy locally) reduce total welfare, and can rarely be justified in terms of income distribution (because the best tradeoff between total welfare and income distribution comes from taxation and redistribution).

<comment><USER6> If the product costs/benefits are equal, why not buy local? Was there an assumption that buying local is a less attractive deal?

<comment><USER3> If the product costs/benefits are equal, why not buy non-local? It seems like your avoiding discussing the actual reason I gave for why local vs non-local is not a valid criterion for judging potential investment opportunities.

In general, if you think that some property of a product is good, then you are implying that you should buy it even when it would otherwise be a less attractive deal. In the language of economics, you would say that property enters your utility/decision function.

</comment></comment></comment><comment><AUTHOR> Hi, one of the developers here. This is just a little side project I built with a financial analyst friend. Uses government data from the FDIC / FFIEC / NCUA and an open algorithm Bob developed to rank banks based on local impact. Clearly more we could do here but wanted to release an easy to use tool that could help people find and promote community banks. Response has been good so far, just won a social innovation challenge grant. Your feedback and thoughts (improvements, issues, etc) all very welcome. tia.

<comment><USER7> Seems like a cool idea. Nothing comes up when I search cities in VA. And when I went directly to their pages I got a rails error:

[http://banklocal.info/locations/va/3174-virginia-beach- va](http://banklocal.info/locations/va/3174-virginia-beach-va) [http://banklocal.info/locations/va/827-richmond- va](http://banklocal.info/locations/va/827-richmond-va)

<comment><AUTHOR> Ha! My Redis instance just fell over :) Things should be back to normal now. Apologies for the inconvenience.

Seems like if you just search for 'Virginia' Google Places will plop you down in a rural part of the states where there aren't any banks within the default 5 mile radius. If you expand that search area a bit (or select a city) you'll see more options.

Thanks for taking a look!</comment></comment></comment>


Online Word Counter - <AUTHOR> http://wordcountr.com A simple to use word counter! <comment><USER2> I like the histogram. I like the style. It would be really cool if you collected all the words over time and present a global top ten... But the trolls would probably put naughty words up.

<comment><AUTHOR> Thanks, its something I knocked up in a day.

The plan is to make a Natural Language Engine, giving you all sorts of interesting facts about your block of text.

I didn't think of doing a history of all text, thats actually a really cool idea! I'll have a bit of a think about how to implement this in a nice way.

What you see is the first step to hopefully something that I can grow over time.</comment></comment>


Thoughts on how to find alternate algebra-like systems - <AUTHOR> http://westoncb.blogspot.com/2017/10/thoughts-on-how-to-find-alternate.html <comment><AUTHOR> Author here: I'm mostly wondering if this is a direction people have looked into before, or if it might be interesting after all, or if anyone can point out to me why it's probably nonsense :)</comment>


YC W16- Why I joined SendBird and Why do I stay? - <AUTHOR> https://kimchihill.com/2020/02/24/why-i-joined-sendbird-and-why-do-i-stay/ <comment><AUTHOR> Thank you for reading my blog. This article is about why I joined a YC startup SendBird back in 2015 and what led me to come to the states in 2017 as a series of the surprising journey. It has been almost 5 years I am with this company, so I wanted to shed a light on why I stay for audiences.</comment>


A drug that can repair cavities and regrow teeth (2017) - <AUTHOR> http://www.loopinsight.com/2018/02/21/scientists-have-found-a-drug-that-can-repair-cavities-and-regrow-teeth/?utm_source=loopinsight.com/twitter&utm_campaign=twitter&utm_medium=referral <comment><USER2> If you have a cavity, try repairing it yourself. (I did as a poor college student) If the cavity is visible and you can work with it, you may want to try and see if your body can do it on it's own.

At the very least, you can have a fun biology experiment.

First, stop eating anything that eats away your tooth. (coke, I am looking at you..., coffee, sugary and acidic stuff, etc...) Clean out the cavity, I used a toothpick and some hydrogen peroxide. Every day clean it out and keep it clean. Swish copious amounts of spit around in your mouth regularly, all day. That's it.

I fixed a large hole in the side of my molar doing this. (dentist didn't believe me years later, but I have a witness, lol)

<comment><USER3> I do something similar. I wash my mouth twice a day with listerine ultra- clean, which contains 20% alcohol. I leave it in my mouth for about 2 minutes and push my teeth together to get the mouthwash into the gums. This has a funny side effect of killing bacteria that is in the plaque on the teeth. Their remains stain the outer layer, but it comes off easily and makes removing the plaque really easy.

I also don't eat anything with added sugar and I take supplements, amino acids, enzymes, extra vitamin d, calcium, chelated magnesium to keep calcium from building up in arteries.

A filling became brittle and fell out about 18 years ago. I completely ignored it. I've had zero problems with my teeth since and have not returned to a dentist since then.

<comment><USER2> I applaud your focus on health. It's not an easy thing to change in life.

What happened to your tooth where the filling fell out? Did it fill in at all naturally? (ie, fully or partially in any way?)

Not sure about the listerine, as I think some (or most?) bacteria in our mouth is supposed to be there. There may be some long term issues to consider. But who knows, everyone is affected so differently, I no longer am dogmatic about what will help or not these days.

Last note on the calcium build up in arteries (off topic a bit), but any build up in the arteries is now known to be a good thing, as it's keeping you alive by repairing a rip/tear in the artery. Even doctors are starting to admit this. It's a bandage, not a blockage.

<comment><USER3> The tooth somewhat repaired, minus the enamel. There is still a divot that I must keep clean, but it is easy to clean.

Bacteria is required in the gut, but AFAIK, it is not required in the mouth. I certainly replenish bacteria in my gut with 20 different cultures.

Excess calcium in the arteries will build up and become blockage. In my younger years I ate many bad things and now I have to be careful not to add to the existing layers.

<comment><USER2> I suspect that some bacteria from the mouth ends up in the gut? I have not researched this topic at all, so I am just surmising.

> _Excess calcium in the arteries will build up and become blockage._

You may want to look into recent studies, they are finding that when an artery is "scratched" (white sugar can scratch arteries) deposits (plaque) are designed to cling to this damage and are a repair tool. If your diet is poor, it can cause damage (as it seems you already know) but also being overweight, lack of exercise, and other things can contribute to weak cellular structure so arteries are more easily damaged.

(note, I got this info from friend who recently had a heart attack and went to the Mayo Clinic, and this is the info they passed on, and is confirmed elsewhere online)

<comment><USER4> > (white sugar can scratch arteries)

I don't doubt that white sugar is damaging to arteries and effects the microstructure of arterial walls, but I'm skeptical that there's a statistically significant difference between white and brown sugar for cardiovascular health. Can you cite any studies that break out white vs. brown sugar?

White table sugar is nearly 100% sucrose and water, while brown sugar has a tiny percentage of molasses and iron, and perhaps traces of other minerals.

I'm skeptical that the tiny percentage of iron and molasses present in brown sugar is protective of arteries. Also, any sucrose in your blood is in solution, not crystaline. What's the mechanism for this "scratching", and why isn't it (as you imply) also present with brown sugar?

I'm not saying you're wrong, but the most plain reading of your post suggests a mechanism (physical scratching, presumably from microcrystaline sucrose) that doesn't make sense to me. Does the sucrose form some large complex with some serum protien, where it's formation is inhibited by something in the molasses present in brown sugar? (Unless someone is massively iron deficient and consuming massive amounts of brown sugar, white vs. brown sugar should have no measurable effect on iron levels in the body.) Or, did you not mean to imply that brown sugar is any better for your arteries than brown sugar?

At work, those times I put sugar in my coffee, I do use brown sugar, but I do it for the difference in flavor and recognize that when mixed into coffee, I'd likely fail a blind taste test. At home, I don't pay the extra cost of brown sugar.

<comment><USER2> > _I don 't doubt that white sugar is damaging to arteries and effects the > microstructure of arterial walls, but I'm skeptical that there's a > statistically significant difference between white and brown sugar for > cardiovascular health. Can you cite any studies that break out white vs. > brown sugar?_

I have no studies to cite right now, my son just did a research paper for school on the effects of white processed sugar though. He may have something, but I feel this would require more effort than just googling this.

The source I got from this was a doctor at the Mayo Clinic, who treated my friend. I would consider this a reputable source. (but hard to properly reference)

Modern brown sugar is just white sugar with molasses added back to it. I have no sources for this though, just info I've run into, and my experiences with real brown sugar (looks nothing like the stuff in the store). Look up Sucanat, a brand of unprocessed sugar, it still has the molasses in it, but it's dry. :P

Edit: This article from Mayo Clinic seems to saying the connection between refined sugar and heart disease is unclear, the message I got from my friend (through doctor at Mayo) was that it was not unclear.

[https://www.mayoclinic.org/healthy-lifestyle/nutrition- and-h...](https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy- eating/in-depth/added-sugar/art-20045328)

Also, another friend (don't talk to her as much so I forgot this one) is that refined sugars cause inflammation in arteries. I can't recall if she had gone to Mayo as well, but that was from her doctor as well.

<comment><USER4> Ahh, you sound confused by the sugar industry marketing.

Brown and "raw" sugar are still processed sugars by many definitions. For instance, see [[https://www.cancercenter.com/discussions/blog/natural-vs- ref...](https://www.cancercenter.com/discussions/blog/natural-vs-refined- sugars-whats-the-difference/)] Brown, raw, and white sugar are all extracted and highly concentrated from the harvested plant products. When you read about processed suger in medical research, they're almost certainly making a distinction between extracted and concentrated sugars vs sugars that are still bound in plant products such as fruits.

I don't doubt that these studies and the Mayo Clinic doctor warned your friend about processed sugars. However, they were almost certainly directing towards fruits and vegetables and away from white sugar, brown sugar, and "raw" sugar (which is a marketing term for a still highly processed sucrose extract from plants).

And while we're throwing around Mayo Clinic doctors, my dad recently retired, but he was a practicing physician who did his residency at the Mayo clinic, and he certainly considers brown and "raw" sugar to be processed sugar.

<comment><USER2> > _Ahh, you sound confused by the sugar industry marketing._

I don't think so, I agree with you. All of those sugars are processed. What did I write that made you think otherwise?

I don't need a doctor to tell me if something is bad for me or not, but it seems to be very useful for many people, hence the Mayo sources. But my point in referencing Mayo was also to demonstrate that this is becoming common knowledge.

Sucanat is simply juice from a cane plant with the water removed. This is not a "processed sugar". My personal opinion is this is a plant extract.

</comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER5> I had to dig through a few pages that summarized eachother like Russian nesting dolls before finding this: [https://www.nature.com/articles/srep39654](https://www.nature.com/articles/srep39654)

This is kinda fascinating.

The original article was published in Nature over a year ago. The summary/futurist speculative news article was published in October, that was included in a '10 daily links' post today and then from there it was summarized on loopinsight.com.

</comment><comment><USER6> more accurately, "we did some mouse trials last year that looked promising, so, maybe!"

[https://en.wikipedia.org/wiki/Tideglusib](https://en.wikipedia.org/wiki/Tideglusib)

<comment><USER7> [https://www.nature.com/articles/srep39654/figures/2](https://www.nature.com/articles/srep39654/figures/2) doesn't look like mice teeth at all.

<comment><USER6> And yet, they are.

From the methods section,

 _" The purpose of this study was to investigate whether natural dentine repair could be enhanced by stimulating the formation of reparative dentine. Adult CD1 wild-type mouse first molars were used and damage stimulated by controlling drilling (see below). The drugs of choice and vehicle were based on previous reports in the literature and also translational potential into a simple, cost effective dental therapy."_

</comment></comment></comment><comment><USER8> I feel like I've read a variation of this headline every six months or so for the last decade, and nothing ever seems to come of it.

<comment><USER9> Same here! Seems to pop up every 6mo to a year, but yet nothing ever changes in the industry. I just found out I have a cavity and the dentist wants to fill it. I am trying to avoid it at all costs though, so this is pretty timely for me. The problem is that its in between my teeth, and even when I try really hard with brushing and flossing in the area, there still seems to be food particles that get in.

<comment><USER10> Get that taken care of bruh.

</comment></comment></comment><comment><USER11> The actual scientific article is January 2017:

[https://www.nature.com/articles/srep39654](https://www.nature.com/articles/srep39654)

</comment><comment><USER12> Not so long ago on HN: [https://www.scientificamerican.com/article/instead-of- fillin...](https://www.scientificamerican.com/article/instead-of-filling- cavities-dentists-may-soon-regenerate-teeth1/)

<comment><USER13> And here: [https://news.ycombinator.com/item?id=16013803](https://news.ycombinator.com/item?id=16013803)

</comment></comment><comment><USER14> An anecdote fwiw:

I rarely brushed my teeth as a child, and had numerous cavities. But for some reason, they only occurred on my baby teeth, not my adult teeth.

My brushing habits atrophied further and by the time I was 18, not only was I not brushing at all, but I never went to the dentist again, except for once in my mid-30s. The dentist admonished me over lack of brushing and the plaque buildup on my teeth, but there were still no cavities or irregularities. I've not been to a dentist in the 10 years since then, and on the very rare occasions (once a week or two weeks) where I do brush, I don't use tooth paste (kept forgetting to buy some).

I keep waiting for the hammer to drop, but so far lucky.

<comment><USER15> How do you handle the aesthetics part: residues, breath,..?

</comment></comment><comment><USER16> Remember, brushing does the most good when you do it _before_ you eat. The bacteria in your mouth take mere seconds to start acidifying the surfaces of your teeth, and research has shown that most of the damage to enamel is done within about half an hour after eating.

Brushing soon after you eat, while the surface pH is still low, can actually damage your teeth beyond the damage done by the acid alone.

[http://www.rdhmag.com/articles/print/volume-24/issue-2/colum...](http://www.rdhmag.com/articles/print/volume-24/issue-2/columns/periodontics/brush- before-eating.html)

<comment><USER17> So can someone please invent a toothpaste that's not heavily mint flavored? I'd rather have my food taste like food.

<comment><USER18> There are plenty available. Of the top of my head I'm aware of are fennel and strawberry from Tom's of Maine, which are pretty widely available. A quick search shows lemon, mango, cinnamon, and pomegranate are also available from others. Might take some trial and error, but hopefully you can find one you like.

</comment></comment></comment><comment><USER19> Another dentistry advancement that won't leave the lab.

</comment><comment><USER20> We've had this before. It never seems to make it into the mainstream.

</comment><comment><USER21> Now, lets assume i grow some elephant stem cells into molar-cells- and apply this strategy to 3d print fake ivory and rhino - maybe the slaughter can still be stopped.</comment>


Raspberry Pi – UASP, Trim, and Boot Performance via USB - <AUTHOR> https://www.jeffgeerling.com/blog/2020/raspberry-pi-usb-boot-uasp-trim-and-performance <comment><USER2> Wow, the animated gif of the Defrag running sent me _way_ back.

I used to run that like it was religion, watching the blocks all move together and change color, and knowing the machine would run just a bit faster after it was all done was a bit of magic.

<comment><USER3> It _felt_ like you were cleaning and tidying up.

</comment></comment><comment><USER4> Just wanted to say thanks for doing this research on flash speeds and posting your results for the last few years, they've helped me pick both reasonable sd-cards and mid-cost USB thumb drives that work for my budget and RPi 4.

</comment><comment><USER5> Samsung Evo+ cards with the same speed rating (say U1) and model number can vary in performance quite a bit. I have tried three of them on my rpi4, and found one which was considerably faster than the others. To be sure I verified it with crystaldiskmark and indeed, it was up to 2x faster in writes and reads.

Samsung cards tend to outperform other brands in that price range.

</comment><comment><USER6> Good to see you up here on the front page Jeff, well-deserved for all your RPi tutorials and videos.

<comment><AUTHOR> Ha, good to see you in the comments too!

</comment></comment><comment><AUTHOR> tl;dr - the Pi 4 now has USB boot enabled by default, and you can get way better performance from a fast USB 3.0 drive than the built-in microSD.

I like the Arcanite for large files and basic storage needs, or an NVMe + USB 3.0 adapter for the best performance for a reasonable price.

UASP can speed up operations by up to 50%, and many SSDs and high end flash drives do support it. TRIM support is less prevalent, and you often need to manually enable it (there's a guide linked in the post).

Weirdest finding: the Arcanite flash drive firmware indicates it supports trim, but when I tried running fstrim something blew up in the drive, and I could no longer read/mount/initialize it from Mac/Linux/Windows (I had to buy a replacement to finish the testing).

<comment><USER7> Do you mean the Arcanite flash drive literally let the smoke out or did it just stop working?

<comment><USER8> Not likely to be smoke. However TRIM failures were very common with SSDs early on and even today some distros disable or partially disable it by default (see for example this Debian warning: [https://wiki.debian.org/SSDOptimization#WARNING](https://wiki.debian.org/SSDOptimization#WARNING)). Upstream Linux does not enable TRIM for MD-raid devices unless you use a special kernel boot parameter. "Continuous TRIM" (which means setting the discard parameter on the filesystem so that files are automatically trimmed on deletion) is also a good way to reveal bugs and problems, some of which will merely kill performance when you delete files, and others will nuke your data.

</comment></comment></comment><comment><USER9> Does anyone have any experience how reliable is such modern USB attached storage when run 24/7? Some years back I made a box (x86, not RPi) with a bunch of USB connected drives (from Western Digital, if I remember correctly). After a few days of uptime the drives would simply drop from the bus. I was guessing there was a bug in the drive's USB controller.

These devices are usually meant to be used as a carrier that's only connected to a computer to load/off load data. Long-term operation probably isn't a priority when developing them.

<comment><USER10> Not related to USB, but flash storage quality in general varies a lot.

We have a few hundred Raspberry Pi in operation at customer sites, running 24/7\. Back when we started our business we used generic Micro SD (can't remember the brand). They would fail after 2-6 months. This was a big hassle. We have customers all over Germany and would need to ship them a complete RPI as a replacement, as the customers are usually not tech-savvy enough to just replace the SD.

We now use SanDisk's "Industrial" Micro SD and haven't had this problem since.

Also, reducing writes to the SD is certainly a good idea. Ideally - if you can - mount the system as read only.

<comment><USER11> Interesting you mention "Industrial" cards as I have been looking at cards in this range after reading quite a few issues with RPIs over the past few months. I have a RPI3 with a SanDisk Extreme, running for 18 months 24/7 with no issues yet. Plenty of re-imaging and high temps. RPI 4 has a SanDisk Ultra, only been running for 3 months 24/7\. Now whilst we all should have backups anyway, I really don't want the worry or hassle of restoring backups couple of times a year, I would rather have a card that will last years rather than months.

Slightly off topic but I have also been looking at using net boot instead. Not only would it be just as fast as the Micro SD cards but much easier to perform backups locally and offsite.

</comment></comment></comment><comment><USER12> How does this change with LUKS enabled? I don't see a point of storing data unencrypted these days.

<comment><USER13> For normal laptops it won't be so much difference in performance, as LUKS by default uses AES-XT as the encryption type, and most modern CPUs have AES accelerators in them.

For rPi though? Not sure they have an AES accelerator, and if they don't then it's going to be a huge cost to performance.

Not only because USB is using a CPU core to operate (because USB uses CPU not dedicated hardware like FireWire) but also because it has to transparently translate and encrypt every access.

It seems like the raspberry actually has zero crypto extensions anyway: [https://www.raspberrypi.org/forums/viewtopic.php?t=207888](https://www.raspberrypi.org/forums/viewtopic.php?t=207888)

<comment><USER14> >Not sure they have an AES accelerator

The ARM chips in the all of the Raspberry pis do not have AES accelerators. Encrypting your pis drive is going to be a serious hit on performance like you said. I don't recommend it.

If you really really really want to encrypt your Rpi then you need to use a disk cipher like Adiantum. It is based off of ChaCha12 and was made specifically for low end CPUs that lack AES accelerators.

</comment></comment></comment><comment><USER15> These reports always comment on raw performance without checking if the drive actually meets the storage contract with the host.

That's like having a 'hall of fame' for the fastest marathon runners, but not having anyone keep an eye on if they took a taxi half the route...

These benchmarks should always have a section where a drive has its power pulled repeatedly while under heavy load. If, ever, a single sector becomes overwritten, rolled back, or unreadable, except those being written between a pair of write barriers, then the drive has failed the test, and all other performance results thrown out. That drive took the taxi.

</comment><comment><USER16> As an end user of Raspis and all their improvements over the past few years, to anyone connected to or working on the project, thank you.

</comment><comment><USER17> I've a rpi4 that I'm setting up as a media player. Files come from a NAS. In the past (rpi3) I've just used an SD card in the Pi. I'm curious if I'd get better performance using USB. Also curious if I did use USB if I could setup automatic caching to the drive.

<comment><USER4> I'm using an RPi 4 as a NAS/home server and the difference between SD speeds and USB speeds was pretty noticeable (subjectively); even simple linux commands (ls, cp -r, mv) sped up after switching to a SanDisk Ultra Flair. Except for one USB drive...

Recently I had the misfortune of having a debian update screw up my docker daemon and I ran over to Best Buy to grab any-old-USB drive to use as a new OS drive. As it happens the SD copy over went fine, but as I performed basic "setting the server up" operations like copying over the old data (50 GB of various sizes) and firing up docker-compose scripts, performance deteriorated rapidly to the point where a docker install of a lighttpd container took at least 30 minutes and the system became effectively unusable.

The poor-performing drive was the PNY Elite-X Fit, USB 3.0, 128GB, purchased for ~$22

I've switched back to a SanDisk SD card for the moment which is perfectly adequate for the next few months but I hope to get back to running off a USB soon when I'm not so busy.

</comment></comment><comment><USER18> Is there a reason the XPG SX8200 256GB SSD with 3500MB/s wasn't tested? Would there be a performance boost compared to what was tested on the Pi 4?</comment>


Startup allows you to get a list of your competitors' customers - <AUTHOR>

Fan Harvest http://fanharvest.com/ allows you to plug in your competitors' facebook page names and gives you a list of their most engaging customers. You can use this data to advertise on Facebook to only these people. This is the best kind of targeting Facebook ads. The results are phenomenal with about 10% CTR. <comment><USER2> Crafty! I might be mad, but I'm avoiding interactions, professional or personal, with Facebook. Would be nice if [http://fanharvest.com](http://fanharvest.com) (clickable!) offered integration with other networks.

<comment><AUTHOR> If I am not wrong, Twitter is coming pretty soon. They also have something called Folwd [http://folwd.com/](http://folwd.com/) that allows you to keep your social profiles updated.

</comment></comment><comment><USER3> Hi mukeshitt, thank you for recommending Fan Harvest.

<comment><AUTHOR> My pleasure. Good stuff guys. How is it working for you?</comment></comment>


The Age of the Never-Ending Performance Review - <AUTHOR> https://www.bloomberg.com/view/articles/2016-08-22/the-age-of-the-never-ending-performance-review <comment><USER2> More frequent performance feedback is a good thing. Just don't think for a second that it changes the nature of the employer-employee relationship.

The employer wants: best work at the lowest price. The employee wants: to do best work (hopefully) at the highest price.

That tension in price comes into play in all the big (hiring, raises, promotions, bonuses) moments of this relationship and the deck is mostly stacked against the employee.

What's an employee to do? Get leverage. And when i say get, I mean earn it (because you work hard and smart and are killing it at work) and show it (be savvy). You need to track every instance of your good work, every demonstration of your value to the company. You need to know what form your performance feedback will take (quick meeting? annual review? panel?) and be ready with all the ammo/leverage/savvy/whatever you want to call it. You have to be able to show what you're worth, what the company loses by losing you (loss aversion works on your boss too) and all that.

<comment><USER3> That's small ball leverage. Real leverage is being irreplaceable so that if you leave they're screwed. Think of it like being a monopolist supplier. Competition depresses wages, so the way to be rich is to be a monopolist. Straight out of Peter Theil, though I don't think he'd like this version as much.

<comment><USER4> "Never make yourself indispensible. If you can't be replaced, you can't be promoted."

\-- Something I once read somewhere. I can't say I've followed its advice, but I also can't say I've observed it to be false.

<comment><USER5> Personally I don't want to be promoted. Promotions suck. Just keep feeding me hard technical problems and keep administrative and management responsibility as far away from me as possible and I'll be happy.

<comment><USER6> Unfortunately the indispensible employee generally isn't the one getting fed hard technical problems, he's the one responsible for maintaining the complex, mission-critical _thingy_ that only he understands and which seems to break down on a regular basis.

I do not envy the indispensible employee.

<comment><USER7> It's a trade off. I got in at 9.30, left at 5, was overpaid and spent most of my day reading HN, doing side projects, or playing cool js games like that cat one. My only meaningful responsibility was to make sure we didn't break down too much or for too long, and that took a few hours a week.

I think that for some people that would have been a trade off they'd be happy to make (and in many ways it _was_ attractive), I think if I'd got on with the people I worked with I might still be there.

</comment></comment></comment></comment></comment></comment><comment><USER8> >Of course, companies that turn themselves into unpleasant places to work will presumably drive away the best workers.

The hand wavy, market-will-solve-it, get-out-of-jail-free-card of our generation raises its greying head again.

A) You can only leave a firm if you have a sufficiently fluid job market for your skills.

B) Firms will be dystopian, and managers will follow the latest HR fad or mantra that infects their CEOs or competitors. "Forever criticism" will most likely make it much worse.

c) We have repeatedly shown that human beings are terrible at assessing their own inabilities, while also being influenced by non critical factors during assessments of situations. The most likely scenario - forever criticism combined with an annual review, will provide people with just the kind of data minefield to blow each other up with.

D) Tools like this are an effort to bridge a paucity of managerial experience. The solution to this is to give people actual managerial experience - i.e. identify and train managers (not leaders), or teams which can self manage.

(side note - to achieve D, you need people to work in firms long enough for the investment to be worthwhile.)

<comment> UK-AL If you don't have the skills you probably don't deserve to be paid lots. So that's a non issue

<comment><USER9> "...don't deserve to be paid lots..."

Yet what people "deserve" has absolutely nothing whatsoever to do with what they are paid. Do you think people in negotiations sit around thinking "what does this guy deserve?" Or are they just trying to get the best bang for their buck like anyone else?

<comment> UK-AL If you have the skills you don't even need strong negotiation skills.

You always have the ability to just get multiple offers and walk away from the worst.

<comment><USER10> I agree with your point higher up but couldn't disagree more strongly with this:

> _If you have the skills you don 't even need strong negotiation skills._

If you have absolutely shit negotiating skills, or don't even negotiate, you are going to be paid less than you deserve forever. You might get a few lucky offers where the initial offer is actually close to market, but more often than not you're getting an 80-90% market offer the first time around.

You combine developer pay being as high as it is, the majority of raises and promotions being based off previous salary, and compounding interest, and it's not unreasonable that no or poor negotiation could leave over a million dollars on the table over the course of your lifetime.

<comment> UK-AL It's very hard for companies to do this, if you have multiple offers.

You say I've got a better offer from x, and they will have to beat or say no. You keep doing this, eventually you will reach market price regardless of negation skills.

<comment><USER11> Wrong. If all the offers are around the same, you're still right where you were.

<comment> UK-AL If all offers are the same, that's a strong indicator to say that's your actual value and not anyone low balling you

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER12> I work at a 50-ish person services agency. We used to do reviews at the end of every project. Everyone staffed to the project has the option of publicly or anonymously evaluating anyone else, and we offer the option for clients to give us their feedback on anyone they want.

What we found is that nobody gives a shit. People with glowing reviews... still leave the company (even with reviews tied to bonuses). People who are great performers still get shit reviews from their peers based on personality instead of merit.

So it's pretty much all just shit that wastes time.

We dropped reviews in favor of public praise mechanisms where anyone use an open mic at our weekly staff meetings to praise a co-worker if they feel so inspired (holy fuck it's a lot of sales people patting each other on the back though), and a karma-tracking tool that keeps a tally in Slack. We also send out a very simple questionnaire at the end of a project to our employees, clients, and contractors... it's in a Google Form and they can opt not to leave their name... we just ask, "What sucked about this project?"

Love to find a better way to do it... but meh, I don't want to waste any more time on this. We all know who we like to work with, we know bosses give bonuses based on who they like, and anything else is just a BS time-sink designed to make you lie to yourself.

<comment><USER13> > holy fuck it's a lot of sales people patting each other on the back though

Meanwhile at my company the engineering boss spends a brief time every monthly meeting pleading for somebody--anybody--to submit nominations for corporate recognition. Not sure if it's mass-imposter-syndrome or just high expectations or what.

</comment></comment><comment><USER14> This is why HR people are HR people and don't do real work other than negotiating the health plan.

Systems like this are trivial to abuse. Several years ago, I worked for a company that was poised to expand a line of business that I happened to be in, and we wanted to get certain people positioned to move up and certain other people to stay where they were.

We didn't have a micro-management system in place, so we did what you do in the absence of process: email. We did a traditional propaganda campaign. "Wow. Betty Sue really did a great job at X!" "Joe had a bit of trouble getting things going, but Mike helped close it." "Betty Sue and Mike rocked that TPS report meeting!"

Instead of coming up with creepy ways to gather intel to let you do whatever you want while avoiding discrimination lawsuits, hold managers accountable for performance and give them the ability to manage.

</comment><comment><USER15> I recently moved to a SW company that does this every 6 months. I haven't been through the review process yet but it seems all consuming for 3 out of the 6 months. My manager has a team of 7 and it seems like he spends half his time on this.

Since I work on HW my projects are long-term and they don't fit this review cycle very well. I also think it causes people to do a lot of nonsense stuff as they desperately try to "make an impact" during the review period. A lot of stuff is done that is a distraction in the name of making an impact.

I get the need to measure people and provide feedback but this constant review shit is ridiculous. In my experience it's clear who is pulling their weight and who isn't.

<comment><USER16> It may be clear to you, but it's probably less clear to management. This gives them a "pulse".

<comment><USER15> If you are managing small teams of people and don't know if they are pulling their weight, then the problem is that you aren't a very good manager.

</comment></comment></comment><comment><USER17> More frequent feedback isn't anything new. This is how one is _supposed_ to manage.

Look, if you walk into a performance review and you don't know how it's going to end, your manager is doing it _wrong_.

Your manager should know your strengths and weaknesses. They should know your successes and failures and _why_ they were successes and failures. They should know your goals and form a plan for you to help you accomplish them (a serious plan, not some "well, they make us list three goals every year" crap). The only way to get that is to have open, frequent communication with you.

A good manager is there to help you succeed. If not, they're just a boss.

</comment><comment><USER18> 360 performance reviews suffer a similar problem in that the savvy folks will all give each other positive feedback. In fact this is the ultimate solution to the prisoners dilemma. Management is looking to divide and conquer which in the long run will hurt even the best performers. Because even the best are human and occasionally have performance issues outside of their control. Not to mention the inequality in work assignments with respect to high value business goals.

<comment><USER19> And engineers with Libertarian slants happily go along with it while their masters laugh.

<comment><USER20> Laugh what? It doesn't seem efficient.

<comment><USER21> But only shareholders care about aggregate efficiency. Managers do too, of course, in the abstract, but not nearly as much as they do about their own careers. You don't even need to be a bad actor for this to be true.

</comment></comment></comment></comment><comment><USER22> Well, isn't it ironic that Bloomberg still uses stack ranking and (quoting the article) encourages managers to actively "manage out dead wood"?

The performance reviews I've experienced in my time at Bloomberg were some of the most forensic shit I'd ever faced. Every misstep counts against you, and "the talk" isn't far behind.

</comment><comment><USER23> The problem of "not enough feedback" is far more pervasive than that of "too much feedback". However, most companies that try to resolve this issue try a One Size Fits All approach for all employees, rather than customizing the feedback solution. Different groups of employees need different frequency and intensity of feedback: client-facing employees typically benefit from more feedback than engineers.

</comment><comment><USER24> Some on HN bemoan the lack of a "true" meritocracy. Maybe these never-ending, always-on performance evaluation and feedback loops are a dream come true for the HN majority. But as the author states towards the end of the article, everybody else will be left by the wayside as inequality grows between the be[st|tter] performing and "other" people.

The question remains to be seen which side of the line the majority of HN readers fall.

Of course, the more cynical amongst us may sneer and think "yet another social system for fakers to game." They probably wouldn't be wrong either, but seems on the surface that continuous performance evaluation will be slightly harder to game.

<comment><USER25> No way. Fuck that.

I have quit jobs over their idiotic daily meeting rituals. Continuous evaluation does nothing for team performance.

Firing people hurts morale. Hiring people who suck hurts morale.

Making people who suck, suck in public on a daily basis hurts morale.

Forcing people who actually get shit done, to mire themselves in tedium and busy work, and engage garish displays of self-appraisal, not only interrupts actual work, distracting from things that count, but provides for a constant atmosphere of interrogation.

Playing the daily meeting, and weekly status game is shit. I won't do it. Never again. Not for any amount of money.

Know what you want before you assign it to me. I'll get it done. Don't ask me are we there yet? Are we there yet? Are we there yet? You child. Grow some patience. The car ride is over when I park the car.

<comment><USER26> While I probably wouldn't use such strong words, I absolutely agree. The daily standup/frequent performance review has disastrous effects on productivity with no discernible benefit. It appears to be something that management can do to cheaply create an illusion of managerial productivity.

<comment><USER27> If you're not willing to use strong language, then you might be part of the problem.

<comment><USER28> Good communicators don't need to swear or yell to make points.

<comment><USER27> The best ones do.

<comment><USER29> You're a fucking idiot.

<comment><USER27> Fuck you pal!

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER30> be wary of any feedback loop that is visible to HR and permanently stored in their systems.

and be wary of bosses who rely on these system rather than taking you out to coffee and actually investing in you as a human being.

<comment><USER31> At this point, I'm convinced that people go into HR because they aren't competent enough to do anything useful with their careers. My firm's HR people have wasted hundreds of thousands of dollars of our time holding mandatory webinars to give us information that could have been contained in 2-3 paragraph emails.

<comment><USER32> That's a pretty broad generalization. I've seen my fair share of crappy HR groups, but I've also seen good ones. Just as I've seen some terrible Dev groups, as well as some good ones.

<comment><USER31> Yeah, I was definitely being unfair. I was irritated with my HR people when I wrote that comment.

</comment></comment></comment></comment><comment><USER33> Oh good USSR style spy on your neighbors is back for corporate monetization.

You know, I watched a few episodes of the English show Black Mirror about how technology is used for vile dystopian hellscapes like this but it got too depressing to watching after about 3 of them.

How long before this is directly tied to your social media by the companies that require access to your accounts?

<comment><USER34> Requiring access to your social accounts is laughable. Unless it's directly tied to your job, it's a signal to quickly and politely end the relationship.

</comment></comment><comment><USER35> "... it's easy to see how some workplaces could turn pretty dystopian pretty quickly"

Frankly, it's hard to see how they could get much worse than they are right now.

<comment><USER36> Watch it, they'll think you're challenging them.

</comment></comment><comment><USER37> Yellow submarine! What a great way to advertise your products to other managers and HR departments who might use them.

I find in practice these web tools are just used to run typical annual / semi- annual perf reviews and give the company an excuse to give people raises and promotions in a non-adhoc manner. Everyone bitches about the time it takes to do them and it's usually a low priority extra thing you have to do.

It feels like school report cards in essence.

</comment><comment><USER38> Anybody found that any of the continuous feedback tools are actually helpful either as the employee or manager?

<comment><USER39> I'd be curious if anyone who has worked at Valve has any insights they would like to share.

It's worth pointing out that Linus Torvalds has a successful continuous feedback system -- and it is his 99% job to provide feedback. I only mean that he doesn't write as much of the Linux code any more, day-to-day, he mostly just reviews patches.

<comment><USER40> A recent _rant_ from Linus Torvalds on commenting style: [https://lkml.org/lkml/2016/7/8/625](https://lkml.org/lkml/2016/7/8/625)

<comment><USER41> What's so bad about that? It actually seems like a pretty sensible and well argued bit of feedback - with some slightly colorful language but nothing that seems that extreme.

<comment><USER42> It's honestly rather long winded for something the compiler isn't going to give two hoots about. :)

When it comes to syntax, I personally think that the best policy is to pick one style, and stick with it. I have come to distrust people with passionate rants like this about syntax because, in my experience, in a few years there probably will be another syntax that falls in fashion, and all of a sudden this New Syntax that now is The New One True Way that everyone gets passionate about, and you have to be high to actually like Old Syntax or something.

What can happen in long term projects is syntax mishmash. Not terribly a big deal with comment formatting, but annoying for other things. Wonder if that variable you are trying to remember is camelCase, underscore_notation, or sHungarianNotation? Is the table you are joining to using Id as a key, TableId as a key, or Table_Id as a key? That's more annoying than any of the problems any syntax has.

So Linus's rant only would be useful to me if his opinion on comment formatting has been consistent over the years. :)</comment></comment></comment></comment></comment>


Ask HN: Best ways to recruit grad students for freelance work? - <AUTHOR>

I am looking to build a modestly reliable stable of graduate level students in a specific field of study (life sciences) for ongoing writing projects that need specialist knowledge: the freelance writing rates on the table aren't likely to be attractive to anyone much beyond the starving grad student years, and they have the necessary knowledge for the job. So hopefully win-win.
Unfortunately, I am so far removed from that stage of life that it's a research project for me to figure out how best to reach that demographic - the times, they have changed.
More generally: how would the minds of HN go about an advertising or recruitment-for-part-work effort targeted at graduate students in a particular narrow field of study? What are the tools and approaches out there that can help with this? <comment><USER2> I got caught up in the publishing vice and often tapped into the graduate student pool when I was looking for writers with the research chops to delve into one of my juicier subjects. One of the most effective tools I discovered was to get professors I am friends with to introduce me to professors in the field that I was looking to cover. Once I had my 'in', those professors were always extremely open to introducing me to graduate students they personally know, or more generically, introducing me to Graduate Students' Associations (every University I know of has one, or something similar).

If I didn't know any professors, I would likely go directly to Graduate Student Associations, though be prepared - higher education can feel rather closed off, so they may view you with suspicion until you get your in!

</comment><comment><USER3> When I was in graduate school, my department's website maintained a list of students who signed up as "tutors", willing to tutor undergraduates in exchange for cash.

Maybe this is less common outside of math (as there were a ton of low-level math courses), but this was surely a reliable way of finding grad students looking for paying work.

But warning: if the projects are _ongoing_ , I feel like you might need to pay well, at least $30/hour. My suspicion is that anyone who would accept less is liable to not be very busy (never a good sign in a grad student).</comment>