Statisticians Find They Can Agree: It's Time to Stop Misusing P-Values - <AUTHOR> https://fivethirtyeight.com/features/statisticians-found-one-thing-they-can-agree-on-its-time-to-stop-misusing-p-values/ <comment><AUTHOR> The article submitted here leads to the American Statistical Association statement on the meaning of p values,[1] the first such methodological statement ever formally issued by the association. It's free to read and download. The statement summarizes into these main points, with further explanation in the text of the statement.

"What is a p-value?

"Informally, a p-value is the probability under a specified statistical model that a statistical summary of the data (for example, the sample mean difference between two compared groups) would be equal to or more extreme than its observed value.

"Principles

"1\. P-values can indicate how incompatible the data are with a specified statistical model.

"2\. P-values do not measure the probability that the studied hypothesis is true, or the probability that the data were produced by random chance alone.

"3\. Scientific conclusions and business or policy decisions should not be based only on whether a p-value passes a specific threshold.

"4\. Proper inference requires full reporting and transparency.

"5\. A p-value, or statistical significance, does not measure the size of an effect or the importance of a result.

"6\. By itself, a p-value does not provide a good measure of evidence regarding a model or hypothesis."

[1] "The ASA's statement on p-values: context, process, and purpose"

[http://amstat.tandfonline.com/doi/abs/10.1080/00031305.2016....](http://amstat.tandfonline.com/doi/abs/10.1080/00031305.2016.1154108)

<comment><USER2> > "3\. Scientific conclusions and business or policy decisions should not be > based only on whether a p-value passes a specific threshold.

There is no lower threshold at which the data becomes non-predictive?

<comment><USER3> More likely they mean the opposite: that a statistically significant P value (by whatever threshold you decide to use) should not be used, by itself, to drive policy decisions. Internally, the effect size still matters. Externally, there are numerous other factors that should drive decisionmaking.

<comment><USER2> Right, but I guess what I'm getting at is frequently we see people doing even worse: making policy decisions based on data that doesn't even hit a minimum threshold for acceptability. I totally agree that people shouldn't make policy decisions solely because the data supports it, but frequently you see people make decisions based on data _indicating_ something without actually being statistically significant. That feels like a bigger problem to me than people actually getting good data but then using it too confidently, which I have rarely if ever seen.

TLDR: People tend to make policy decisions based on data even when the data is basically useless, I'm more worried about that then blindly following good data.

<comment><USER4> One issue is that if you have a large effect that's consistently and easily reproduced, you don't actually need very accurate measurements or a statistical analysis at all. So any minimum standard would need to take into account.

Another issue is that science is expensive and we need to make decisions all the time whether there is any science backing them or not. So what do you do if there's no science that meets the minimum standards?

<comment><USER2> > One issue is that if you have a large effect that's consistently and easily > reproduced, you don't actually need very accurate measurements or a > statistical analysis at all.

I mostly agree with this, but you never have that in a difficult decision.

> Another issue is that science is expensive and we need to make decisions all > the time whether there is any science backing them or not. So what do you do > if there's no science that meets the minimum standards?

Right! My entire point is that maybe data driven decision making isn't as useful as we think because it mostly doesn't hit scientific levels of accuracy. Maybe there are other, more intuitive systems, that make as much if not more sense, in absence of good data. How would we even know either way? We can't!

Regardless I'd love for the discussion to be "this is the best we can do" rather than "yes we did A/B testing so we _know_ it's true!!!"

<comment><USER5> >> One issue is that if you have a large effect that's consistently and easily reproduced, you don't actually need very accurate measurements or a statistical analysis at all.

> I mostly agree with this, but you never have that in a difficult decision.

Consider the problem "should we cure congenital deafness in infants?"

To Deaf Community Leaders, this isn't a difficult decision at all; they are strongly against curing deaf children because it makes their power base smaller.

To deaf parents of deaf children, this is a tricky choice. Curing the child's deafness dramatically improves its prospects in life, but it also inevitably cuts the child off from the parents' community. You have to choose between how good you want your child's future to be, and how close you'd like your relationship with them to be.

To hearing parents of deaf children, this is again a trivial choice; obviously you'd cure the child.

BUT, curing deafness is definitely (1) a large effect that is (2) easily reproduced.

<comment><USER5> Having thought a bit more about this, I want to disagree more strongly with the sentiment "you never have [large, reproducible effects] in a difficult decision". I think difficult decisions necessarily involve that kind of effect.

A couple of things might make a decision difficult:

\- Some course of action will produce a big effect. Would that be good or bad?

\-- Ok, assume there's a good effect out there to be achieved. Is it worth the cost of obtaining it?

Those questions, variously applied, occupy a lot of people's time and brainpower. In the curing-a-deaf-child example, the parents are making a tradeoff between quality of their child's life (which is good), and closeness to their child (also good). Paying one for the other means giving up something good, which makes the decision nontrivial. But this is a difficult decision because the effects are _large_ , not because they're small.

In contrast, if you're dealing with an effect of very small size, or one that can't be reproduced ("lose weight by following our new diet!")... this might feel like a difficult decision, but it shouldn't. It _does not matter_ what you decide, because (by hypothesis!) your decision will have no effect on the outcome! (Or, for the "very small effect size" case, at most a very small effect.)

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER6> I agree as well!

Here is what probability theory teaches us. The proper role of data is to adjust our prior beliefs about probabilities to posterior beliefs through Bayes' theorem. The challenge is how to best communicate this result to people who may have had a wide range of prior beliefs.

p-values capture a degree of surprise in the result. Naively, a surprising result should catch our attention and cause us to rethink things. This is not a valid statistical procedure, but it IS how we naively think. And the substitution of a complex question for a simpler one is exactly how our brains are set up to handle complex questions about our environment. (I'm currently working through _Thinking Fast and Slow_ which has a lot to say about this.)

Simple Bayesian approaches take the opposite approach. You generally start with some relatively naive prior, and then treat the posterior as being the conclusion. Which is not very realistic if the real prior was something quite different.

Both approaches have a fundamental mistake. The mistake is that we are taking a data set and asking what it TELLS us about the world. When in probability theory the real role of data is how to UPDATE our views about the world.

This is why I have come to believe that for simple A/B testing, thinking about p-values is a mistake. The only three pieces of information that you need is how much data you are willing to collect, how much you have collected, and how big the performance difference is. Stop either when you have hit the maximum amount of data you're willing to throw at the test, or when the difference exceeds the square root of that maximum amount. This is about as good as any simple rule can do.

If you try to be clever with p-values you will generally wind up putting yourself at saving yourself some effort in return for a small risk per test of making very bad mistakes. Accepting small risk per test over many tests for a long time puts you at high odds of eventually making a catastrophic mistake. This is a very bad tradeoff.

I've personally seen a bad A/B test with a low p-value rolled out that produced a 15% loss in business for a company whose revenues were in the tens of millions annually. It. Was. Not. Pretty. (The problem was eventually found and fixed..a year later and after considerable turnover among the executive team.)

<comment><USER7> _Simple Bayesian approaches take the opposite approach. You generally start with some relatively naive prior, and then treat the posterior as being the conclusion. Which is not very realistic if the real prior was something quite different._

I don't think this is a completely accurate portrayal of Bayesian stats. In Bayesian stats, there is no "real prior". Probability distributions are all subjective representations of belief. The prior is just what you believe _prior_ to evidence, and the posterior is what you believe after you've taken evidence into account.

That said, moving away from p-values and towards something more robust is something the A/B testing industry needs. (Obviously I have my own opinion of what that something should be, and it's a bit different from what you are advocating.) There are far too many consultancies and agencies p-hacking their way to positive results ("hey unsophisticated client - guess what I made your conversion rate go up 25%!") and I'd love to see every one of them die.

<comment><USER6> There are different approaches a Bayesian might take. The one that I described is certainly among them, though it is not the only one.

<comment><USER8> I think the word "naive" is problematic here. Have you seen instances where Bayesians choose a prior that isn't at least somewhat informed by exploratory analysis?

<comment><USER9> It's quite common to choose a conjugate prior, which aids computation, and which is readily comprehensible within the discipline ("...and a Wishart prior for the covariance, of course..."). But which is, in effect, not at all informed by the data.

It's also common to have a complex, multi-level model setup which has a few hyperparameters (say, gamma distribution shapes) which are set basically arbitrarily. The idea being that the posteriors for the lowest levels (closest to data) will be learned/fitted, but the hyper parameters at the top-level of the model are fixed. This is very common in spatial statistics.

It's also common to make lots of (conditional) independence assumptions, just because they are convenient. Such as diagonal covariances, or conditional independence between "separate" elements of a model. But these independence assumptions are often just convenient or based on intuition, but not re- checked. Or, if they are checked and found wanting, it's "left for future work".

These practices are defensible, and attackable. But choosing convenient priors out of a bag of standard priors, without reference to the problem at hand, is very common.

</comment></comment></comment></comment></comment><comment><USER10> It's not just p-values. Some people just don't understand even very basic statistics.

I remember talking to one person in marketing who ran surveys of the company's users. They would send out a survey to all registered users, get back responses from 1% of them or something, and then proceed to report findings based on the responses. They were really happy, since a 1% response rate is great for surveys like this.

I tried to explain to them that all of this statistical machinery relies on having a random sample, and a self-selected sample is not that. No effect whatsoever. Surveys like this are standard practice in the industry. Why are you making trouble, geek-boy?

<comment><USER11> " Surveys like this are standard practice in the industry."

So, how does one exploit this apparent bad practice? I.e., how does one make a profit from others making this mistake? The answer is, of course, one doesn't - otherwise others would've done so. So what does this tell us about the state of affairs? Is it that bad sampling doesn't matter for practical purposes, or that marketing research is useless? I don't know, and I'm not trying to be belligerent here. A situation similar to this shows up in dozens of places every day - more often than not, it doesn't matter if things are done 'right', there are large margins within which 'good enough' is indistinguishable from 'right'.

This bothers me greatly, but it's hard to argue against this conclusion, empirically. How to deal with this cognitive dissonance? I mean this is the exact topic at least half of the blog posts that make it to the HN front page deal are fundamentally about.

</comment></comment><comment><USER12> P-values are so weird. Studies should instead report a likelihood ratio. A likelihood ratio is mathematically correct, and tells you exactly how much to update a hypothesis.

You can convert p-values to likelihood ratios, and they are quite similar. But its not perfect. A p value of 0.05 becomes 100:5, or 20:1. Which means it increases the odds of a hypothesis by 20. So a probability of 1% updates to 17%, which is still quite small.

But that assumes that the hypothesis has a 100% chance of producing the same or greater result, which is unlikely. Instead it might only be 50% which is half as much evidence.

In the extreme case, it could be only 5% likely to produce the result, which means the likelihood ratio is 5:5 and is literally no evidence, but still has a p value of 0.05.

Anyway likelihood ratios accumulate exponentially, since they multiply together. As long as there is no publication bias, you can take a few weak studies and produce a single very strong likelihood update.

</comment><comment><USER13> For context, I have a degree in statistics, and I did research with Andrew Gelman (one of the statisticians quoted in the article).

Glad to see this is gaining traction! I've been saying this for years: the world would actually be in a better place if we just abandoned p-values altogether.

Hypothesis testing is taught in introductory statistics courses because the calculations involved are deceptively easy, whereas more sophisticated statistical techniques would be difficult without any background in linear algebra or calculus.

Unfortunately, this enables researchers in all sorts of fields to make incredibly spurious statistical analyses that _look_ convincing, because "all the calculations are right", even though they're using completely the wrong tool.

Andrew Gelman, quoted in the article, feels very strongly that F-tests are always unnecessary[0]. I'd go as far as to extend that logic to the Student's t-test and any other related test as well.

You can get into all sorts of confusing "paradoxes" with p-values. One of my favorites:

Alice wants to figure out the average height of population. Her null hypothesis is 65 inches. She conducts a simple random sample, performs a t-test, and determines that the sample mean is 70 inches, with a p-value of .01.

In an alternate universe, Bob does the same thing, with the same null hypothesis (65 inches). He determines that the sample mean is 90 inches, with a p-value of .000001.

Some questions:

A) Does Bob's experiment provide stronger evidence for rejecting the null hypothesis than Alice's does?

B) In Bob's universe, is the _true_ population mean higher than it is in Alice's universe?

By pure hypothesis testing alone, the correct answer to both questions is "no", even though the intuitive answer to both questions is "yes"[1].

[0] [http://andrewgelman.com/2009/05/18/noooooooooooooo/](http://andrewgelman.com/2009/05/18/noooooooooooooo/)

[1] Part of the problem is that we _do_ expect that, in Bob's universe, the true population mean is highly likely to be higher, and this _is_ supported by the data. Trouble is, the reason we expect that is not formally related to hypothesis testing and t-tests/p-values.

<comment><USER14> If you're doing a measurement, why have a null hypothesis? Alice should sample the population at random, take the height measurements, calculate the average, plot the distribution, calculate the variance. If the distribution is not sufficiently smooth then continue to take measurements until it's smooth, or unchanging. Then Alice is done discovering all there is to know about the height distribution of the population she sampled. Same with Bob.

<comment><USER13> > Alice should sample the population at random, take the height measurements, > calculate the average, plot the distribution, calculate the variance

A student-t test is basically a lossy encoding of that information you describe (the sample mean, the variance, and the sample size).

> If the distribution is not sufficiently smooth then continue to take > measurements until it's smooth, or unchanging.

From a frequentist standpoint, this would be considered sloppy and bad methodology. You don't keep sampling until you get the results you want (or until the null hypothesis is invalidated).

That said, as I mention in a comment above, the fact that you _can_ keep sampling until the null hypothesis is invalidated (and that it is mathematically always guaranteed to happen eventually) is a big problem with the concept of hypothesis testing in the first place.

</comment></comment></comment><comment><USER15> Is the p-value really not the probability of your results being due to chance? Is that not a perfectly valid definition of it?

I suppose 'chance' is a little hand-wavy, but isn't a p-value just the probability of your data given that your hypothesis is false? Isn't that literally and precisely the probability that they occurred by chance?

<comment><USER16> Imagine I handed you a 20-sided die. I claim it says 7 on every side, but I might be lying. You roll a 7. What are the chances it actually has 7 on every side?

You can't actually say unless you either (1) roll the die more times, or (2) assume something about the probability that I gave you an all-7's die to begin with.

Doing (2) is useless, because that exactly the question we are trying to answer.

For example, suppose I perform this experiment all the time and I know that I give an all-7's die only 1% of the time. With this new information, you could actually calculate the probability of an all-7's die given a 7 roll. Of all the possible outcomes, you could add up the ones where I gave you an all-7s die _and_ the ones where I gave you a normal die but you just rolled 7. Then you could divide that by the total number of possible outcomes.

But this would give you a totally different number than if I give you an all-7's die 99% of the time. And the problem is that you don't have any information about what kind of die you have before you roll it. You're trying to figure out which world we live in -- one where your hypothesis is true or one where it's not.

(I am pretty sure that what I wrote above is true. But one thing I'm not as clear on is how multiple rolls of the die actually can establish confidence percentages. How many rolls does it take to actually establish confidence? Would love to hear from any stats experts about that.)

<comment><USER17> rolling the die more times just lowers the P value. You still can't make a definitive statement on the probability that it's an all-7's die without assuming something about the prior probability.

However, if you can bound the prior probability on the low end, you can make meaningful answers. Let's say you think there's at least a 1-in-a-billion chance that you have an all-7's die. After five rolls in a row of 7, there's at least a 0.3% chance that you were handed an all-7's die. After six rolls there's a 6% chance, and so on.

Usually this quantitative analysis isn't formally done, since the priors can always be debated, but rather a very small P value is demanded for very unlikely events.

</comment></comment></comment><comment><USER18> Next step is explaining social science students the meaning of 'randomness' :)

Really, the amazing amount of bullshit social studies I have seen 'proven' by statistics. Amazing new insights like 'if children wear green shirts, while the teacher has a blue shirt the cognitive attention span is 12.3% higher than children wearing purple shirts. The effect was measured with a significance of bla bla bla.'

Software like SPSS facilitates this even more. People with no notion of random effects or probablilty theory click on the 'proof my research' button and even get it published.

So a lot more work in this area!

</comment><comment><USER19> In undergrad, I learned how to about p-values but never quite understood how they were actually useful. Now, as a bioinformatics graduate student, I've come to understand that my original instinct was right all along.

</comment><comment><USER3> Statistical significance is difficult to ensure. Certainly, one should be suspicious if 0.05 is _ever_ used as a significance threshold, because it's unlikely that exactly one hypothesis under one regime was tested in any given paper.

I am glad that the article's headline is clear that it's time to stop _mis_ using P-values. Tests for statistical significance should still be used, and to abandon them would be foolish. In a sense, though, they are the beginning, not the end, of assessment.

</comment><comment><USER14> p-value analysis has its big caveats like multiple comparisons, but Bayesian has its own, such as it's extremely hard to calculate priors. Both are challenging to use in difficult analysis and both can be abused.

<comment><USER20> > such as it's extremely hard to calculate priors.

I think you mean it is difficult to formulate priors? Typically, calculating a prior only involves sampling from a distribution.

<comment><USER14> Let's use this example: [http://betterexplained.com/articles/an-intuitive-and- short-e...](http://betterexplained.com/articles/an-intuitive-and-short- explanation-of-bayes-theorem/)

-1% of women have breast cancer (and therefore 99% do not).

-80% of mammograms detect breast cancer when it is there (and therefore 20% miss it).

-9.6% of mammograms detect breast cancer when it's not there (and therefore 90.4% correctly return a negative result).

For generating a prior, I posit it's really hard to determine that 1% of women have breast cancer, and this prior is almost linearly sensitive to whether you actually have cancer:

prior | % likelihood of cancer

2% | 16%

1% | 7.8%

0.5% | 4%

Why do I think it's hard to determine the prior? Imagine you are a 34 yrs old woman in SF. Do you use the rate of breast cancer for only 34 yr olds? For the range of 30-40 yr olds? 30-65 yr olds? For women only in SF? In the bay area? In California? Data from 2000-2016? 2010-2016? This becomes hard because positive cases are rare (thank god), so the population of which you calculate the prior from can be noisy. Imagine if the positive result occurs 1e-5 times.. you are talking about 10's of cases every million. Vary the prior probability and your posterior probability will vary just as much.

<comment><USER20> hmm, what you are discussing above is typically called the formulation of the prior, not the calculation of it. And I agree that this formulation can be problematic. It is almost certainly the most contentious element in Bayesian inference.

However, I will note that your examples are largely overstating the problem. The prior is not typically as subjective as you are implying. Furthermore, the Bayesian prediction converges to the frequential result in the limit of 'large' data. If your results are so highly sensitive to your prior that the results drastically change, then you either have:

1) insufficient data, at which point the frequentist results would also certainly have been as bad or worse (the prior acts as a regularization) 2) a misspecified prior

Either way, it is absolutely required that you perform tests to ensure your results are _not_ greatly sensitive to your choice of prior, or if so that this is clearly noted as a modeling assumption. And bayes naturally has many means to test precisely this, such as cross-validation, bayes-factors, hierarchical, etc.

I also note that this is why I typically prefer Jeffreys Priors in my work. I mention this so that one can see that not all priors are 'subjective'. These are difficult to use in some fields, admittedly.

</comment></comment></comment></comment><comment><USER21> The #1 problem is with p-values is the word "significant". We should use "detectable" instead. Significant implies meaningful to most people, but not in a statistical context. This is quite confusing. Detectable is better because the mainstream meaning aligns with the jargon.

So:

> "Discovering statistically significant biclusters in gene expression data"

becomes:

> "Discovering statistically detectable biclusters in gene expression data"

This rephrasing makes it evident that "statistically detectable" adds little to the title. So the title becomes

> "Discovering biclusters in gene expression data"

A better title.

</comment><comment><USER22> This excellent and amusing article by Gerd Gigerenzer discusses the history of p-values and their (mis)use:

"Mindless Statistics"

[http://library.mpib- berlin.mpg.de/ft/gg/GG_Mindless_2004.pdf](http://library.mpib- berlin.mpg.de/ft/gg/GG_Mindless_2004.pdf)

or

[http://www.unh.edu/halelab/BIOL933/papers/2004_Gigerenzer_JS...](http://www.unh.edu/halelab/BIOL933/papers/2004_Gigerenzer_JSE.pdf)

</comment><comment><USER23> The article tends to imply P-value should not be used at all, rather than misused. P-value definitely means something. For example, if the p-value is 1e-10 (which is often possible), you know for sure that the hypothesis generating has been disproved. So let me rephrase the title of the article - "It's time to use P-Value correctly."

</comment><comment><USER24> Wow, I remember having these reservations about p-values when I took classes in stats but whenever I brought them up a prof. would wave their hands and be dismissive. They gave me a degree in political science, but I felt that political science was an oxymoron and it left me with no respect for the field.

<comment><USER13> > They gave me a degree in political science, but I felt that political > science was an oxymoron and it left me with no respect for the field.

For what it's worth, Andrew Gelman (quoted in the article) is one of the most pre-eminent Bayesian statisticians alive, and is a professor in both the department of Statistics and Political Science!

"Political Science" need not be an oxymoron, even if a lot of self-professed political scientists use rather unscientific methods.

</comment></comment><comment><USER25> ...and I could not find the word "correlation" anywhere in this article discussion statistics, harm, misunderstanding, and studies. Shame.

</comment><comment><USER26> If people would just learn to resample (cross validate, use subsampling or the bootstrap), we wouldn't be having this pointless discussion at all.

<comment><USER27> In theory, you are correct, but some data sets are too small or make it too difficult to cross validate in a way, that is meaningful to the original problem

</comment></comment><comment><USER28> This is one of the best conversation threads I've ever seen on HN. It's both polite and informative.

I want to toss in my own thoughts here.

Since I've spent the vast majority of my tech career in the Market Research industry (hello, bias!), I'm tempted to say that one of the most frequent intersections between statistical science and business decisions happens in that world.

Product testing, shopper marketing, A/B testing . . . these are pretty common fare these days. But I feel like the MR people are sort of their own worst enemy in many cases.

It's a fairly recent development that MR people are even allowed a seat at the table for major product or business decisions. And when the data nerds show up at the meeting, we have to make human communication decisions that are difficult.

I can't show up at the C-suite and lecture company executives about the finer points of statistical philosophy. When I'm presenting findings to stake- holders, it's my job to abstract the details and present something that makes a coherent case for a decision, based on the data we have available.

It is sinfully attractive to go tell your boss's boss's boss that we have a threshold--a number we can point to. If this number turns out to be smaller than .05, this project is a go.

Three months later, you go back to that boss and tell him the number came back and it was .0499999. The boss says, "Okay, go!" And then you are all, "Wait, wait, wait. Hang on a second. Let's talk about this."

My god, what have I done?

The practical reality of the intersection of statistics and business is a harsh one. We have to do better. In terms of leaky abstractions, the communication of data science to business decision makers is quite possibly the leaky-est of all.

Why is it so leaky? I have two points about this.

1) Statistics is one of the most existentially depressing fields of study. There is no acceptance; there is no love; there is nothing positive about it. Ever.

Statistics is always about rejection and failure. We never accept or affirm a hypothesis. We only ever reject the null hypothesis or we fail to reject it. That's it.

2) In business, we tend to be very very sloppy about formulating our hypotheses. Sometimes we don't even really think about them at all.

Take a common case for market research. New product testing. We do a rep sample with a decent size (say, 1800 potential product buyers) and we randomly show five different products, one of which is the product the person already owns/uses (because that's called control /s). The other 4 products are variations on a theme with different attributes.

What's the null hypothesis here? Does it ever get discussed?

What's the alternative hypothesis?

The implicit and never-talked-about null is that all things being equal, there is no difference between the distribution of purchase likelihood among all products. The alternative is that there is a real difference on a scale of likely to purchase.

The implicit and intuitive assumption is that there is something about that feature set that drives the difference. (I'm looking at you, Max Diff)

But that's not real. It's not a part of the test. The only test you can do in that situation is to check if those aggregate distributions are different from each other. The real null is that they are the same, and the alternative is that they are different.

All you can do with statistics is tell if two distributions are isomorphic.

Now, who wants to try to explain any of that to your CEO? No one does. Your CEO doesn't want it, you don't want it, your girlfriend doesn't want it. No one wants it.

So we try to abstract, and I feel like we mostly fail at doing a good job of that.

This is getting really long, and I don't want to rant. So to finish up, an idea for more effective uses of data science as it interacts with the business world:

I agree, let's stop talking about p values. Let's work harder and funnel the results of those MR studies into practical models of the business' future. Let's take the research and pipe it into Bayesian expected value models.

Let's stop showing stacked bar charts to execs and expecting them to make good decisions based on weak evidence we got from hypotheses we didn't really think about in the first place.

Some of this might come across as a rant. I hope it is not taken that way. This is a real problem that I've been thinking about for a long time. And I don't mean to step on anyone's toes. I have certainly committed many of the data sins that I'm deriding above.

Edited to add:

The real workings of statistics are unintuitive. I'm not saying that they are wrong. But in working with people for years now, I understand the confusion. It's a psychological problem. Hypotheses are either not really well though out or not considered in an organized way, in my experience.

A hypothesis is not concrete in many practical cases. It's a thought. An idea, perhaps. It's often a thing that floats around in your mind, or maybe you paid some lip service and tossed it into your note-taking app.

Data seem much more real. You download a few gigabytes of data and start working on it. It's quite easy to get confused.

I have real data! This is tangible stuff. Thinking of things properly and evaluating the probability of your data given the hypothesis is _hard_. Your data seems much more concrete. These are real people answering real questions about X.

Even for people who are really hell-bent on statistical rigor, this is a challenge.

</comment><comment><USER29> If they held the same meeting 20 times, would they reach the same conclusion in 19 of those meetings?

On a more serious note, I think that the use of the word "significant" to mean "the effect is reasonably likely to exist by some standard" should be abolished.

Webster's 1913 dictionary says:

> Deserving to be considered; important; momentous; as, a significant event.

Statisticians don't use "significant" to mean important at all -- they use it to mean "I could detect it". This is bad when someone publishes a paper saying "I found that some drug significantly reduces such-and-such" \-- this could just mean that they did a HUGE study and found that the drug reliably had some completely unimportant effect. It's much worse when it's negated, though. Think about all the headlines that say that some treatment "did not have a significant effect". This is basically meaningless. I could do a study finding that exercise has no significant effect on fitness, for example, by making the study small enough.

A good friend of mine suggested that statisticians replace "significant" with "discernible". So next time someone does a small study, they might find that "eating fat had no discernible effect on weight gain", and perhaps readers would then ask the obvious question, which is "how hard did you look?".

This would also help people doing very good research make less wishy-washy conclusions. For example, suppose that "vaccines have no discernible effect on autism rates". This is probably true in a number of studies, but _it 's the wrong analysis_. If researchers who did these studies had to state the conclusions in a silly manner like that, maybe they'd find a more useful analysis to do.

Hint: doing big studies just so you can fail to find an effect is nonsensical. Instead, do big studies so you can put a tight upper bound on the effect. Don't tell me that vaccines don't have a significant (or discernible) effect on autism. Tell me that, with 99.9% confidence, you have ruled out the possibility that vaccines have caused more than ten autism cases in the entire history of vaccines, and that, most likely, they've caused no cases whatsoever (or whatever the right numbers are).

Edit: fixed an insignificant typo.

<comment><USER30> That's the _second_ definition in Webster's 1913 edition. The first is:

> Fitted or designed to signify or make known something; having a meaning; > standing as a sign or token; expressive or suggestive; as, a significant > word or sound; a significant look.

It seems to me that this is the sense in which statisticians talk about significance. It means that the results actually signify something rather than just being meaningless noise.

<comment><USER29> Interesting. That definition seems like a bit of a stretch in this context to me. Results of trials aren't "fitted or designed" to signify -- they are or are not significant by the p-value standard, and whether they are or are not is random (which is the whole point).

In any event, I suspect that, among most currently living English speakers, the second definition is what comes to mind.

</comment></comment></comment><comment><USER14> 5% (1 in 20) is a pretty weak threshold to pass. Let's go 5 sigma (p < 3e-7) for discoveries and reserve 0.05 < p < 3e-7 for stuff we should take closer looks at.

<comment><USER3> > 5% (1 in 20) is a pretty weak threshold to pass. Let's go 5 sigma (p < 3e-7) > for discoveries and reserve 0.05 < p < 3e-7 for stuff we should take closer > looks at.

This would still end up leading to misuse of P-values. Let's say you're doing a genome-wide association study on several hundred thousand SNPs. The traditional threshold is 5e-8 (0.05 / 1,000,000 effective tests). So using 3e-7 for the threshold for "discovery", you'd count many things as discovery that shouldn't be so.

On the other hand, let's say you do a study with 20 people with cancer. You give 10 of them a drug, the other 10 a placebo. All 10 with the drug survive; all 10 with the placebo die. Your P value is 0.0002. This doesn't count as discovery, but clinically I know what my judgment is going to be.

This is all to say that the misuse of P-values does not just come from the threshold.

<comment><USER14> Multiple comparisons? 1 million independent tests? Hello?

>Your P value is 0.0002. This doesn't count as discovery, but clinically I know what my judgment is going to be.

>Let's go 5 sigma (p < 3e-7) for discoveries and reserve 0.05 < p < 3e-7 for stuff we should take closer looks at.

^Means you should start a new trial with n > 20 given the same placebo/drug split.

<comment><USER31> In the scientific world, it is economically infeasable (cost/time) for 1 million tests for a given hypothesis. Even n > 20 can be difficult for certain studies. Bootstrapping the results to simulate 1 million trials won't fix the aforementioned issue either.

<comment><USER32> > Even n > 20 can be difficult for certain studies.

For some expensive experiments even n=3 is difficult to reach. "Should we do another replicate and go from n=2 to n=3, or should we hire another post-doc?" is a relatively common (rhetorical) question.</comment></comment></comment></comment></comment>


4 Months with Rails - Launching My First App - <AUTHOR>

http://www.uhpartments.com
I bought my first programming book from Amazon on August 17th (Chris Pine's Learn to Program) and have been teaching myself RoR since. I work days at a NYC startup in marketing and operations, so I learned in addition to working about 50 hours a week.
I attended a hackathon, spent hours on Stack Overflow and watching Railscasts, and just got my hands dirty and built something.
I obviously have a long way to go to be a proficient rails developer, but I'm absolutely loving programming, even if just as a hobby.
Would love some feedback! I had previously built http://www.badnycapartments.com as a Drupal site with the same sort of goal, but a year later I'm taking everything I've learned (not just tech but biz too) and re-launching as uhpartments. <comment><USER2> Congrats! It's great that you didn't just sit around on your off time and instead got up and started coding. It's definitely the way to do it.

</comment><comment><USER3> Since UI, simple

</comment><comment><USER4> Good stuff!

</comment><comment><USER5> Congratulation Sbauch. Did you have any previous web-development background like Html/CSS or you learned everything from scratch?

<comment><AUTHOR> I learned html in middle school (2000-2001?) and have always been semi- comfortable with it. CSS too, which I also brushed up on for BadNYCapartments.com.

And I definitely need basic HTML skills for my day job for html emails, things like that.

But this was a whole different ballgame!</comment></comment>


Dataforge UUCP - <AUTHOR> https://uucp.dataforge.tk/ <comment><USER2> Hello! I'm Wes (aka; praetor), the founder of the UUCP project ! I'm humbled my project reached the front page of HN and has generated some interest.

Yes. I do apologize for the documentation being sparse. I'm developing the Tier 1 provisioning scripts, and documenting at the same time. Plus, unfortunately, I have a full-time life. But once I finish the Tier 1 stuff, I can delegate duties out to those with an interest :D

Yup. It's all run via SSH. The preferred server is Taylor UUCP, which is super flexible. I've sent an e-mail to the developer, Ian Taylor, to hopefully revive that project and breath some life into UUCP. It's a fantastically resilient protocol and will run over damned near anything. We've even had some talk of running UUCP over ham radio links!!!

All the Tier 1 hosts are mesh interconnected, so even if one goes down, it doesn't take huge swathes of the network with it. With how the Internet is shaping up to be, if Google goes down, it's taking a huge piece of the network with it. This is really intended to reawaken the DIY ethos the Internet was founded on. Mostly public nixes and tilde servers, but anyone with some dedication can be a Tier 1. We've kinda democratized it that way.

And no, you don't have to be the "right kind of freedom fighter". The Tier 1 operators have a gentleman's agreement to let anything pass through their node to the broader network unless it's something like CP or flagrantly against the law (or spam)

It's an exciting project! It really is a network for the modern nerd, and is ripe for all sorts of projects!

Please join us on IRC @ irc.tilde.chat or subscribe to the project mailing list at firstname.lastname@example.com

See ya on the network! :D

<comment><USER3> To me, merely encrypting the transport layer via SSH is far from secure, especially when the network is used by "hackers" and "freedom fighters". Today, if a network wants to be immune from tracking by design, it should officially support to be accessed from anonymous networks. The UUCP protocol is perfect for relatively high-latency, low-bandwidth anonymous network, like Tor or i2p (Particularly, i2p by itself is a great project, the only issue is the latency of the network is too high for HTTP), it would be great if some Tier 1 hosts can be accessed from Tor/i2p via a raw TCP socket (without SSH, since it's unnecessary and increases overhead in these networks). Illegal content and spam can be a problem, only peering to reputation hosts can solve the problem at large.

<comment><USER2> Nothing says we can't run some nodes via i2p or Tor, and I suspect eventually someone will do it, which I like. I'd like to this to be a place where people with internet censorship can get the world out when Twitter fails. Hence the freedom fighter. We don't impose a transport. SSH is just a good trade off for easy and secure. The ol' UUCP books have to be dusted, so I want to keep the entry reasonably low. Once people are familiar (or re-familiar) with UUCP and feel confident enough to make contributions, I think we'll see this very thing. Like I said, it's ripe for tinkering.

<comment><USER4> Tor should be the only way to link nodes. The only reason for anyone to use batched mail and news in 2019 would be for the security - which means tor.

There is no reason to use SSH, as it expose the IP address of the participants.

Setting up UUCP for mail and news on localhost is not so easy anyway (meaning you must setup an MTA +NNTP daemon unless you do old school QWK), so you might as well ask the person to spend 5 minute to configure an onion address.

Like the previous author, I also strongly suggest you change the design to make it a cool and useful project instead of just a nostalgia fueled hobby (SGI servers??)

</comment></comment></comment></comment><comment><USER5> LOL kids these days. I remember when we first got Internet access and didn't have to batch up a UUCP download late at night any more, what a great convenience! Also things like URLs are remarkably useful; finding a file via UUCP was quite a hassle. I mean as an art project goes, sure, why not? But it's hard to imagine UUCP offers any practical advantages unless you literally don't have an always-on Internet connection.

For more nostalgia, enjoy the UUCP maps: [http://olduse.net/blog/current_usenet_map/](http://olduse.net/blog/current_usenet_map/)

<comment><USER6> In South Africa where I grew up, we had the entire country's internet hanging off a single dialup UUCP gateway at Rhodes University in Grahamstown from 1988 until 1991.

In 91 they replaced the dialup UUCP link with a 9600kbps leased line. Only universities had access. We got our first commercial ISP in 1993.

<comment><USER7> > [ZA] got our first commercial ISP in 1993.

Interesting 'doc' from the Internet Society on the effort from a few years ago on Internet exchange points (IXPs):

* [https://www.youtube.com/watch?v=MFv-9iPwwLE](https://www.youtube.com/watch?v=MFv-9iPwwLE)

</comment></comment></comment><comment><USER8> UUCP is one of those good things that many early ISP providers overlooked, You had companies with an e-mail server that would dial up to the internet to send and receive e-mail and would get a dynamic IP address. This would be no problem for UUCP, but since many newcomers to the internet didn't know it they would use some clunky dynamic DNS system instead. Also if the connection dropped there was no 'resume' feature if this happened during the sending or receiving of a large e-mail, so it would have to start sending or receiving that e-mail all over again.

</comment><comment><USER6> I suspect this is #1 on HN because we are all very interested in ideas that enable decentralized publishing. The trouble with uucp is that it wont take long for a tier 1 node to disconnect a leaf for being the wrong kind of freedom fighter.

</comment><comment><USER9> Interesting. I had no idea someone had layered SSH and certificate auth on top of UUCP.

Used UUCP a lot back in the day to push software updates out to customer machines over dial up.

<comment><USER10> I'd love to read more about these stories. Do you blog?

<comment><USER9> I should, but no. It was a company that sold software to hospitals that would integrate software/servers from different departments via a protocol called HL7. Hospitals were not generally on the internet in the early 90's. So, we would do a week on site installing an AIX box and the software, do a few integrations, etc. Before we left, we'd install a 56k modem.

UUCP was handy because you could push files and run remote commands on a batch schedule without a lot of scripting. We did have some clients that had more complicated setups where we would have to resort to SLIP (serial line IP) and more traditional scripts/rsh/etc. All terribly insecure, with plain text passwords in files...or worse, ".rhosts" files.

<comment><USER11> Same here UUCP setup to trigger syncing of nightly billing runs on SCO(!) Unixware servers.

All the code was written as a combination of Microfocus COBOL and hairy shell- scripts. I recall we had a lot of random SSH-tunnels being held open via keep- alive-pings, and SLIP was definitely something I had to use.

</comment></comment></comment></comment><comment><USER12> Seems interesting, but unfortunately the leaf guide is empty.

[https://uucp.dataforge.tk/~uucp/wiki/index.php?n=Main.LeafNo...](https://uucp.dataforge.tk/~uucp/wiki/index.php?n=Main.LeafNode)

<comment><USER13> Hey, I'm one of the Tier 1 nodes for the Dataforge UUCP project. It's currently a work-in-progress as the Tier 1 guide was only just recently completed. If you are interested in joining as a lead node, you can get help setting it up in #uucp on the tilde.chat network.

</comment></comment><comment><USER14> I remember uucpssh.org[1] which I had bookmarked for a while but didn't get around to setting up before it closed down. Now it resolves to a spam website. Sad!

[1] [http://www.linuxfocus.org/English/March2004/article330.shtml](http://www.linuxfocus.org/English/March2004/article330.shtml)

</comment><comment><USER15> Interesting. I used to have a UUCP email and news feed back in the 90's, for the BBS I ran in high school.

</comment><comment><USER16> I ran AmigaUUCP way back when. I feel tempted to set up UUCP again…

</comment><comment><USER17> Somewhat in a similar vein (in that it provides an NNTP interface and provides for decentralized distribution of newsgroups/mailing lists) is public-inbox [0] which is used by kernel.org for mirroring LKML; it's quite straightforward to get running and has a great technical foundation on git.

[0] [https://public-inbox.org](https://public-inbox.org)

</comment><comment><USER18> I used to run a leaf node in Hawaii with an AT&T 3B1 using its internal 1200 baud modem. My upstream was Pegasus Information Systems, run by by a guy named Richard Foulk.

</comment><comment><USER19> What are "tilde networks"?

<comment><USER20> Tilde.club explains at [http://tilde.club/~faq/](http://tilde.club/~faq/).

<comment><USER21> Also worth checking the Dataforge UUCP site list.

[https://uucp.dataforge.tk/sites.html](https://uucp.dataforge.tk/sites.html)

</comment></comment></comment><comment><USER22> some examples of this in use would be good, the documentation looks a bit sparse.

</comment><comment><USER23> I can haz UUCP+Briar using (in order of preference) GNUnet/i2p/Tor as the underlay with full end to end PGP encryption, Web & Chain of trust & custody attestation, via fully bootstrappable & replicable builds?

No?

Meh. Guess it'll take another 7 years until crypto & libre take off.

<comment><USER4> This. You are downvoted but your technical critique is spot on.

Throw in Monero to pay for services and you've got a great technological stack possible right now, while something like that at the time of the cryptonomicon was just a dream.

It could be a cool project if it took advantages of all the pieces of technology we now have that they didn't have back then - PGP was a late addition, replicable builds not a concern, tor and cryptocurrencies yet to be invented.

<comment><USER23> Thanks. I suspect the downvotes come about due to the rather tongue-in-cheek way I started my comment with, albeit I wanna avoid speculating about reasoning behind downvotes.

Speaking of Monero & paying for services: GNUnet has the GNU Taler project. While not applicable to the same use cases to which Monero applies, it fits into a related niche very much in need of filling.</comment></comment></comment>


Jupiter's North Pole Unlike Anything Encountered in Solar System - <AUTHOR> https://www.nasa.gov/feature/jpl/jupiter-s-north-pole-unlike-anything-encountered-in-solar-system <comment><USER2> Ignoring all the fascinating stuff about Jupiter, let me point out this gem: _The download of six megabytes of data [...] took one-and-a-half days_

I sometimes like to scare kids by telling them about the time when I surfed the Internet with 14.4 kbit modem, but even that looks incredibly fast compared to the speed of interplanetary data transmission (back then, 6 MiB would have taken me about 2-2.5 hours).

(NB that I am not complaining or anything, just pointing out that this is many orders of magnitudes slower than anything one would normally consider a "slow" connection.)

<comment><USER3> It's also fascinating to think about how TCP is ineffective at that distance.

[https://en.wikipedia.org/wiki/Interplanetary_Internet](https://en.wikipedia.org/wiki/Interplanetary_Internet) is a good starting point to learn more.

<comment><USER4> That means when humans finally colonize Mars, there will be two FaceBooks, FB Mars and FB Earth, with any communication between them running at a lag.

I bet there will be AI research to create bots to act in "real time" on your behalf on the opposite planet. If the artificial agent can imitate your own actions and judgements, it would be a good way to surpass the speed of light. It will be necessary to build these agents because other interested parties could use the time lag to unfairly gain an advantage over you. The more we explore, the larger the time lag. With Jupyter it is 33-53 minutes. With Pluto it's 5h. The nearest star - 4 years. The Moon is at 1.3s.

<comment><USER5> The last thing I need is a realtime Facebook now. I feel like I should build in a delay of ~1 week to everything I do.

<comment><USER6> Yes. I world also like to see the delay randomized between 3 and 10 days so that nobody can tell what tempo you're replying at.

</comment></comment></comment></comment></comment><comment><USER7> _"Saturn has a hexagon at the north pole," said Bolton. "There is nothing on Jupiter that anywhere near resembles that. The largest planet in our solar system is truly unique. We have 36 more flybys to study just how unique it really is."_

This is the first I've heard of Saturn's hexagon, very interesting: [http://www.space.com/30608-mysterious-saturn-hexagon- explain...](http://www.space.com/30608-mysterious-saturn-hexagon- explained.html)

<comment><USER8> >The largest planet in our solar system is truly unique.

Hold on -- how much do we know about the poles of gas giants in other solar systems? I'm guessing we can't get a good look or anything...

Edit: added quote to clarify what I was responding to.

<comment><USER9> Saturn has a tilt just a bit more than the Earth and it experiences seasons; the pole is rotated something like 26 degrees into our field of vision in "winter". Uranus is actually rotating on it's side.

[http://www.setterfield.org/Astronomy/pictures/axial-tilt- pla...](http://www.setterfield.org/Astronomy/pictures/axial-tilt-planets.jpg)

<comment><USER10> " _other_ solar systems"

<comment><USER9> The answer is we don't. Unlike the other three gas giants in the Solar System we can't see Jupiter's pole clearly. So Jupiter is unique to our solar system, and we don't know much about the visual details of exoplanets.

<comment><USER11> Is Jupiter all gas or does it have any mass? It is hard for m kind to imagine a big ball of gas looking like a planet and going around the sun

<comment><USER12> The thing is, there's a _lot_ of gas, which like any other matter, has mass. So, even though a hydrogen atom is the lightest element possible, and we think of hydrogen gas a being light, that's just relative to other things. At a human scale, it isn't possible to have that much of the stuff around. But you can always go and collect a lot of it; in fact if you get ten to the power twenty seven kilograms of the stuff, and put it in one place, gravity will shape it into a sphere that looks very like Jupiter. Or, get 1000 times as much as that, and watch as gravity squeezes it so much it begins to fuse into helium at the centre - you'll have a star the size of our Sun...!

</comment></comment></comment></comment></comment></comment></comment><comment><USER13> Absolutely breathtaking.

Interesting that they phrase the headline almost as if to imply uniqueness. My impression was that Saturn's hexagon was the unique situation (occurring, hypothetically, only under very specific conditions). Is it expected then that Uranus and Neptune's poles will look different still?

<comment><USER14> Uranus has an axial tilt of around 90°, so it is undoubtedly completely wacky. I have no idea what Neptune's looks like.

<comment><USER15> No one does. Neptune and Uranus have been visited by only Voyager 2. Neptune's pole wasn't covered in the flyby.

</comment></comment></comment><comment><USER16> I understand Juno flew as close as 4,200km. Are there any pictures from that distance? The closest here says it was taken from 38,000km.

<comment><USER17> Given the exceptionally slow transfer rate, I suspect we will be seeing even better images over the next few weeks.

</comment></comment><comment><USER18> I wonder if the clouds don't separate into bands as much at those latitudes because the velocity (due to the planet's rotation) is lower closer to the poles.

<comment><USER19> The Coriolis force is strongest at the poles and weakest at the equator, so I presume there would be more rotation and thus less banding near the poles due to this effect.

The origin of the banding is supposedly similar to the banding on Earth, which has three broad 'bands' driven by Hadley cells (polar, mid-lattitude, tropical), driven by convective heating moving energy away from the equator towards the poles, except presumably Jupiter has much more energy and therefore more convection and more bands.

I only have a very crude understanding of atmospheric forces, though, so paging someone who knows better.

</comment></comment><comment><USER20> There are only 8 planets in the solar system (well, 9 with Pluto). "Unique" isn't a terribly high bar here.

</comment><comment><USER21> the second video says:

> the infrared data captured a faint aurora

when talking about aurora strength which variable is predominant: the magnetosphere, the atmosphere, or amount of solar radiation?

also, can anyone speak to the reason for the noisy instrument detecting those 3.45 micron wavelengths? why is the bottom edge so active?

</comment><comment><USER22> "The download of six megabytes of data collected during the six-hour transit, from above Jupiter's north pole to below its south pole, took one-and-a-half days."

...surely that's a typo and they mean gigabytes?

<comment><USER23> The solar panels that Juno has produce only 500 watts of power. You would need a lot more then that to be sending gigabytes of data in any meaningful timeframe. So yes it really is just six megabytes of data taking 30h+ to download. Btw the panels would produce 14kW at earth orbit but suns power goes down quite fast as you move away from it. Also the farthest from the Sun we've ever used solar panels. Traditionally missions this far from the Sun have used some kind of a nuclear power source (RTGs). Though I don't think they could produce 500 watts without being very big.

[http://www.jpl.nasa.gov/news/news.php?feature=4818](http://www.jpl.nasa.gov/news/news.php?feature=4818)

<comment><USER24> Transmission is one thing, but collection is another: did they really only collect 6 megabytes of data over the course of a 6 hour flyby?

Off topic, ish: does anyone know how large a solar panel array would have to be to supply all of our current energy use, if the array orbited the Sun at the same distance Mercury does?

<comment><USER25> According to Wikipedia, the world's average energy consumption is 12.3Tw. Given that the Earth is gets 1366 W/m² of solar power at 149,597,870km, this means Mercury gets 9190 W/m² at 57,910,000km. Plugging these together, this tells us that a 12.3Tw solar array of 100% efficiency in Mercury's orbit would have a surface area of 1338 km².

Realistically, you'd at least double that, to produce the same power, as solar panels are <50% efficient.

<comment><USER24> Brilliant, thanks. So how long before we start putting solar panels in close, direct orbit around the Sun?

<comment><USER26> Then we could beam the energy back to earth using lasers so bright that they would burn plasma holes through our atmosphere and precisely target receiving stations where they would vaporize water which would power a steam turbine. Totally doable, I'd say we could get it up and running in a couple years.

<comment><USER24> This sounds like sarcasm, but yes: solar collectors in close orbit around the sun, huge flying parabolic mirrors focusing solar energy that's already 7-10x more dense than it is at 1 AU, beaming that energy to receivers sitting in orbit around the Earth (perhaps at Lagrange 1 and, via L4/L5, L2 to reach the night side of the planet), relayed in to near earth orbit satellites, and being beamed down to many surface locations at safe intensities that might well be used to boil ocean water, driving steam turbines and producing fresh water (and salt).

Such a system could provide energy dense power to the entire solar system (skipping the steam turbine step for most locations, and going pure solar electric), up to large installations for entire planets, and down to individual spaceships.

I'm not suggesting we'll do it tomorrow. But within a hundred years, if we get and keep our shit together..?

</comment></comment></comment></comment></comment></comment></comment><comment><USER27> > _"Saturn has a hexagon at the north pole," said Bolton. "There is nothing on > Jupiter that anywhere near resembles that. The largest planet in our solar > system is truly unique. We have 36 more flybys to study just how unique it > really is."_

Eh? Jupiter is 'truly unique' because it _doesn 't_ have an extremely puzzling feature that only one other planet is known to have?

<comment><USER28> Why are people getting bent out of shape about the word "unique"? It is unique because Jupiter has features that we have not observed on any other planet, some of which are mentioned in the article (different types of storm systems, high altitude clouds casting shadows etc). From context, he is clearly not only talking about Saturn's hexagon. This pedantry is ridiculous.

<comment><USER29> People are confused. As was I at first. Considering the emphasis "truly unique" I expected more treatment of that point by the article. By not having that I was left feeling like I missed something / confused. People generally don't like feeling confused.

Personally, I don't understand the people defending the usage here. As far as I have experienced in my life, when people say "unique" in good faith they mean "one of a kind" and those people who don't use it that way are considered to have done a bait-and-switch.

That said, perhaps there's been a lingustic shift I haven't yet noticed.

</comment></comment></comment><comment><USER30> based on the obvious banding from the side i always assumed the top might in fact look like a hexagon.. looking forward to seeing more!!

</comment><comment><USER31> Where does that infrared heat orginate? Fission?

<comment><USER32> Probably a combination of radioactive decay and gravitational collapse.

<comment><USER31> Probably another dumb question, if you would pump heat into this, and increase the isolation factor - could you produce a brown dwarf?

<comment><USER33> The lower theoretical threshold for a brown dwarf star, which fuses deuterium->lithium, is 13 times the mass of Jupiter. There isn't enough mass for fusion to occur on its own no matter how energetic the particles are.

<comment><USER31> Thanks.</comment></comment></comment></comment></comment>


What was it like to be an executioner in the Middle Ages? - <AUTHOR> https://www.livescience.com/medieval-executioner-life.html <comment><USER2> Upon hearing the sad news of Gene Wolfe's passing in April of this year, I took the occasion to reread his Book of the New Sun series. The protagonist is Severian, a banished member of a Torturers guild, who earns some money during his travels by performing professional executions. It's a little unsettling to immerse yourself in a story written in the first-person narrative of this sort of character.

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

<comment><USER3> The Book of the New Sun is a masterpiece. Although I recommend having a dictionary on hand... preferably one with old English/arcane words.

</comment></comment><comment><USER4> Here's an article about what it's like to be an executioner in the modern era (Saudi Arabia, 2003): [https://web.archive.org/web/20090911101207/http://www.arabne...](https://web.archive.org/web/20090911101207/http://www.arabnews.com/?page=1&section=0&article=27038&d=5&m=6&y=2003)

<comment><USER5> Compared to TFA, it seems sensible.

In particular:

> Before an execution, nonetheless, he will go to the victim's family to > obtain forgiveness for the criminal. "I always have that hope, until the > very last minute, and I pray to God to give the criminal a new lease of > life. I always keep that hope alive."

That's a very different perspective. If the victim's family forgives the criminal, I gather that they go free.

But on the other hand, losing a hand for stealing is horrible.

<comment><USER4> I believe forgiveness in this context refers to the Islamic concept of Diya ([https://en.m.wikipedia.org/wiki/Diya_(Islam)](https://en.m.wikipedia.org/wiki/Diya_\(Islam\)))

<comment><USER5> As I understand it, it's not always about money.

</comment></comment></comment></comment><comment><USER6> Kingdom Come: Deliverance, a medieval RPG, did this quite well. The protagonist Henry does a few jobs for the executioner and they make it clear the isolation and ostracization the executioner suffers, and he lives well out of town.

</comment><comment><USER7> The Hangman's Daughter book series gives a pretty great look into this same topic, dramatic flair aside. They're written by a modern descendent of a Bavarian executioner family who dug into his family's past and then loosely tied some actual historical events into clever stories (basically the definition of historical fiction, I suppose). They were fun beach reads for me that also taught me a lot about 1600s German life.

</comment><comment><USER8> Not in the article, but in the book it self: there is also the function of combating superstition! Lots of people believed incredibly dangerous things. Such as cutting of the (arm or) hand of a new born (and carrying it when you attempt to burglar a house) can make you invisible. This believe was obviously quite dangerous for new borns. Thieves and burglars would sometimes "try their luck". When they got caught it was the executioners job to also demonstrate/ educate the people.

</comment><comment><USER9> 1573 mentioned in article is not Middle Ages, just saying.

<comment><USER10> It's not unimportant. The mistake is (in time) like "what it was to be a computer scientist in WWI". Like... what?

<comment><USER11> Bamberg was not exactly on the cutting edge of the Renaissance, so executions in 1573 might have been about the same as in the middle ages. Bamberg was burning witches into the 1600s.

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

<comment><USER12> Witch trials were a post-medieval phenomenon.

</comment></comment></comment></comment><comment><USER13> It should be added that criminal law that time also meant that executed convicts had to be studied by the general public to inspect any inner deformations or sick organs which could have caused those crimes. So the executioner was also a pathologist who prepared a public autopsy in a special room after the execution. Or there was another special doctor who did that. Many executioners did the autopsy by themselves which raised their profile.

An excellent novel about he executioners business is Pavel Kohout's Katyne.

</comment><comment><USER14> Curious, how many executions per year could there possibly be in Bamberg, Bavaria?

<comment><USER15> The only figures I could see casually were that there were approximately 2,000 per year in England during the reign of Henry VIII...so I guess it's not insane to imagine a mid-size town in Germany having 10 or 15 a year? Which would surely be enough to justify professional help?

<comment><USER16> Beside actual executions, there were torture as a part of crime investigation (in particular to extract confession as the religion insisted that criminal must confess to make sure that no innocent gets punished), plus non-capital punishments:

"During this time, he executed 394 individuals by various methods, and also flogged, disfigured, or tortured many hundreds more."

So, it was pretty busy.

</comment></comment></comment><comment><USER17> This site is toxic on mobile. There ads on top of the text.

<comment> martin-adams Yep, same here. Gave up reading because it was impossible to read.

<comment><USER18> Prepend to the url:

        outline.com/

So:

        https://outline.com/https://www.livescience.com/medieval-executioner-life.html

[https://outline.com/https://www.livescience.com/medieval- exe...](https://outline.com/https://www.livescience.com/medieval-executioner- life.html)

</comment></comment></comment><comment><USER19> I went to the torture device museum show when I was in San Diego about a decade ago.

Seeing how cruelty was inflicted stays with you, so I don't recommend it unless you're studying that area.

The closest analogy is that once you see the goatsie picture, you can't unsee it.

At a higher level, learning how government abused punishment in the past does make you question whether they're any more qualified today.

</comment><comment><USER20> The article only mentions the clean executions (other than burning at the stake). There were plenty that were gruesome; essentially tortured to death.

<comment><USER21> _The Count of Monte-Cristo_ carries a depiction of a public execution that is rather ... vivid. The convicted is clubbed to death. And not too cleanly.

Quick research doesn't say whether this fashion was used in reality or not. The wikipedia article on Italian capital punishment doesn't go into style details.</comment></comment>


Ask HN: Common ratio; hours of work invested to equity retained, in startups? - <AUTHOR> Let us consider 2 web applications, which are pretty far along in development; posit they are both very close to MVP; further, an experienced VC team feels that both apps have rouphly equal potential.  The team developing application A, has invested 3,700 hours and the team developing application B, has invested 1850 hours.  What percent of a company might the devs for app A get for their elbow~grease capital vs the devs for app B, for theirs?  Is there a widely employed ratio for sweat equity or is this alone not a signifigant enough factor amongst all the other considerations, to move the figure much? <comment><USER2> Investment is based on an estimate of the future value of the business, so 'sweat equity' doesn't mean much because it's in the past. If a founder/VC wants to maintain a relationship with anyone who's put work in already then it's not unreasonable to negotiate a small percentage, but it's very unlikely that anything would be based on hours or the monetary value of hours worked so far.

You chose to give your time freely and you could have walked away at any point. You don't get to retrospectively ask for 'payment'.</comment>


Overnight, App for Booking Last-Minute Spaces with Local Hosts, Raises $2.5M - <AUTHOR> http://techcrunch.com/2016/02/25/overnight-the-app-for-booking-last-minute-spaces-with-local-hosts-closes-2-5m-seed-round <comment><USER2> This seems like a good supplement for people who are already AirBnB hosts because such people already have an intention to provide a space, therefore they are inclined to have the space relatively prepared in advanced for a future booking.

Perhaps the UX is difference on this app vs AirBnB, but what prevents someone from using AirBnB for a last minute rental except that the host must be prepared for such an event?

<comment><USER3> It's hard to set up. There is instant booking on AirBnB, but mostly you have to email people and have a conversation, introduce yourself, etc. and wait for the host to get back to you. I have booked relatively last minute on AirBnB, in fact one of my best experiences was at a "startup" hotel in San Francisco, but by and large it's difficult and unreliable. Especially the "request to book" thing. If I put in a request for same day accommodations, I can't put in a second request for fear of both requests being accepted. And requests have, I believe, 24 hours to be accepted. So in theory you could try to book this morning for tonight, and not get a response until tomorrow. Or put in multiple requests and they're all accepted and you're charged for many rooms.

And even if it works, you have to coordinate with the hosts on entrance, parking, etc. at the last minute, which could be impossible.

Generally AirBnB isn't optimized for last-minute bookings in my experience.

When I need something super last minute, I can always rely on Hotel Tonight. But something like this, a last-minute AirBnB without all the AirBnB hassles, would be pretty nice.

<comment><USER2> It seems that last-minute requests on AirBnB do not really succeed because the hosts aren't prepared to respond in time. So, it's a psychological / cultural issue because AirBnB was created without this 'last-minute' booking concept / ability in mind (right?).

Even with this app, don't you still need to coordinate with the host for entrance, parking, etc?

Also, the fact that multiple requests for the same accommodations by the same user aren't consolidated and yield multiple chargings seems like a bug...

The hassle seem more related to what you stated, that AirBnB "isn't optimized for last-minute bookings."

<comment><USER3> Definitely sounds like you would still need to coordinate with the host, but perhaps the different culture and mindset makes people more cognizant of the fact that they have to do the coordination quickly and be ready to do it.

</comment></comment></comment></comment><comment><USER4> So, how do they compete when AirBnb launches this feature in a few month's time?

To be honest, this sounds like a nightmare for hosts. Hotels can do Hotels Tonight because they have paid staff at the checkin desk 24/7 and usually some spare, made up rooms. I'd have to get paid a lot to open up my spare room at a moment's notice.

<comment><USER5> I think this works better for people who don't want to schedule their entire lives around an airbnb calendar. If you have a room / guest house to rent, and you don't have hired help, you need to be there. Ruins the spontaneity of life, like if I want to take a few days off to go on a getaway. I could see this being useful as a seller.

However, as a buyer, it's risky. You need to trust that a room will always be available with your expectations, and you won't know until the same day. It would stress me out.

<comment><USER6> I'd be surprised if this is still around in 3 years. The things you mentioned are the first that came to my mind. Plus, there'll probably be high churn making it even worse for hosts because it'll probably mainly appeal to people caught in a city at short notice, and probably short term in that case.

</comment></comment></comment><comment><USER7> This is perfect for areas and buildings where Airbnb is banned. For example I was renting out my apartment in Chicago for $250 a night until someone from the building management company contacted me saying that rentals or subleases < 1 month were not allowed in my building and I needed to take my place off the site. I removed the listing and asked them how they knew that it was up. Apparently they had an intern look through all of their properties on Airbnb regularly and find all of the Airbnb listings for them. This app would allow me hide my listing from building management but to be visible by verified travelers. I am sure this wouldn't only be true of individual buildings, but entire neighborhoods or cities where it may be banned.

<comment><USER2> You have a window where you can use this app until the building management catches on and adds this app to the ban list.

How does this hide your listing except by putting it on a less known service?

<comment><USER7> For Airbnb all listings are public. In this app everything is private until you let specific users be able to view it.

</comment></comment></comment><comment><USER8> I've always thought that something like this would be very effective for renting "space" rather than it necessarily being a full bedroom. The company could let the apartment/house owner rent fold-able cots or something to utilize, say, a living room as a sleeping space. There would be basic check boxes like access to a shower, a kitchen, etc., but it is more of a free-form lodging rather than renting a room.

</comment><comment><USER9> My brain couldn't help but read it this way for a while: _App for booking raises $2.5M overnight._</comment>


Clyde raises $14M to help e-commerce businesses offer extended warranties - <AUTHOR> https://techcrunch.com/2020/05/11/clyde-raises-14-million-series-a-to-help-e-commerce-businesses-offer-extended-warranty-plans/ <comment><AUTHOR> Four years ago, Brandon Gell was an architecture student who spent most of his time working on 3D printing modular housing. Now, he's the founder of Clyde, an extended warranty startup that wants to help small e-commerce businesses offer product protection. Today, the company announced it has raised a $14 million Series A led by Spark Capital with participation from Crosslink, RRE, Rea Sea Ventures and others.</comment>


Yahoo BOSS service to be shut down - <AUTHOR> Just got this email:
At Yahoo, we're always looking for ways to streamline and simplify products for our customers. With this focus in mind, we will discontinue the BOSS JSON Search API, as well as the BOSS Placefinder API and BOSS Placespotter API, on March 31, 2016.
Access to the BOSS APIs will continue until March 31, 2016. Moving forward, customers leveraging the BOSS JSON Search API can instead use YPA, a Javascript Solution that provides algorithmic web results with search ads for publishers who manage their own search engine results pages (SERPs). <comment><USER2> Announcement: [https://developer.yahoo.com/boss/search/](https://developer.yahoo.com/boss/search/)

The only other option seems to be Bing Search API. Anyone know of a decent other alternative?

</comment><comment><USER3> What does this mean for DDG?</comment>


Revealing Subtle Changes in the World - <AUTHOR> http://nsf-scivis.skild.com/skild2/nsf2012/viewEntryDetail.action?pid=40708

<comment><AUTHOR> Check out our cool video and vote for it if you like it.</comment>


Stemcentrx VC takes shots at Fidelity, Andreessen Horowitz after mega-sale - <AUTHOR> http://www.bizjournals.com/sanjose/blog/techflash/2016/04/stemcentrx-vc-takes-shots-at-fidelity-andreessen.html <comment><USER2> Their xenograft-assay approach sounds painfully difficult so congratulations for apparently pulling it off.

BTW life sciences was the original field where you could get an exit without revenue.</comment>


GPhone Emulator: Try out the gPhone yourself - <AUTHOR> http://thenextweb.org/2008/10/06/g1-emulator-try-out-the-googlephone-yourself/

<comment><USER2> Would be neat if it were a real emulator, but it's just sort of a hacked up flash application.

<comment><AUTHOR> Yeah, but it does give you a sense of what it will look like so it is better than nothing...

</comment></comment><comment><USER3> The browser doesn't work. Is the only and most interesting part of the whole device. Ugh...</comment>


A Mythical Phoenix: Mainframe's Evolution - <AUTHOR> https://www.share.org/blog/a-mythical-phoenix-mainframe-s-evolution <comment><USER2> I don't claim to be an expert here so please correct me but if the mainframe vendors want to extend the life of this technology then they should invest a bit more in helping curious explorers access them. Whether through emulation, documentation which is a bit zippier (i.e., more Whys Guide to Ruby and less 1978 phone book, etc...). The closed nature of information on mainframes means that it's hard for people to catch the bug of interest in them by fooling around first.

<comment><USER3> Mainframe emulator: [http://www.hercules-390.org/](http://www.hercules-390.org/)

Yeah, it's kind of hard to get into the mainframe business. Kind of like getting into piloting a passenger jet. You can't pilot a passenger jet without a few hundred hours of flight time on a jet aircraft.

You can't just buy a used one and fly around on your own. So you hope someone who owns a jet will lug you around until you become competent and certified.

<comment><USER4> I have a z114 and a z800 and a P/390\. Not any harder than for instance owning professional wood working gear.

<comment> le-mark And you have media for the OS you can install on them? And setup and configuration to a useable system is as simple as the guided wizards other OSs provide?

<comment><USER4> Yup. It's not like installing Ubuntu on a laptop but I don't think that's to be expected. IBM does have zPDT which is a lot easier.

</comment></comment></comment></comment></comment><comment><USER5> Whilst it may be true that it can run cobol, one must have to aware the assembler part of the story. Still remember the enjoyment of from 24 to 31 bit. And apar and s/370 assembler language patch.

It is not all colour.

Btw the claim you cannot run old msdos is over stretching. Still running turbo pascal on dos.

</comment><comment><USER6> Waxing nostalgic: I loved working on mainframes back in the day. My job was a little unusual for a mainframe programmer, so maybe that's why: my team was customizing the VM/370 hypervisor and its usual guest OS ("CMS") for our employer's needs. It was mostly 370 assembly, for the OS changes, and the occasional script (or "Exec", as it was called in CMS). I wasn't doing much app development and never saw anything that looked even remotely like JCL.

I loved it, and I would never go back to it.</comment>


Ask HN: Any way to read a 9-track 1/2" tape in Silicon Valley? - <AUTHOR> I'd like to read two old 9-track, 1600BPI open reel computer tapes from the 1980s. Unix TAR format.  They contain source code for 30 year old software, one of the earliest proof of correctness systems. I'd like to upload it to Github for historical purposes.<p>Anyone still have that capability? <comment><USER2> I asked around and Lyle Buckley is the guy to contact for this. He charges for this, but he might be willing to do it pro bono if it's for a good cause.

<comment><USER2> Marc (who's working with me on the Alto restoration) said he could dump the tape into SIMH format, but it would be up to you to untar it from that.

</comment></comment><comment><USER3> Don't know if they have the capability, but an interesting place to start might be the Computer History museum in Mtn View. [http://www.computerhistory.org/](http://www.computerhistory.org/)

<comment><AUTHOR> Their IBM 1401 can't do it. Its tape drives don't go up to 1600 BPI.

<comment><USER3> Might they know someone who has access to that hardware even if they don't have it on hand themselves?

<comment><USER4> Computer History Museum has 1 1401 - [http://www.computerhistory.org/atchm/about-the-computer- hist...](http://www.computerhistory.org/atchm/about-the-computer-history- museums-ibm-1401-machines/)

</comment></comment></comment></comment><comment><USER5> This guy got one. (Man take me back, used to have the HP drive on my first job in the 90's. (Sigh) The bad old days...)

Maybe he'll take pity on you

[https://www.youtube.com/watch?v=CEL8wnW5uvs](https://www.youtube.com/watch?v=CEL8wnW5uvs)

</comment><comment><USER6> How about the US Department of Defense? They seem to love maintaining old tech.

</comment><comment><USER7> There's a chance the living computer museum in Seattle has such a drive.

[http://www.livingcomputermuseum.org](http://www.livingcomputermuseum.org)

</comment><comment><AUTHOR> There are a few commercial data recovery services that can still do it, but I'm being quoted $500 a reel and up.</comment>


RBS Faces $783Million Fine for Manipulating LIBOR - <AUTHOR> http://www.bloomberg.com/news/2013-02-05/rbs-said-to-face-up-to-783-million-fine-for-manipulating-libor.html

<comment><USER2> Where's the jail-time?</comment>


Interview: Reggie Fils-Aime On Garage Devs And The Value Of Software - <AUTHOR> http://www.gamasutra.com/view/news/33595/Interview_Reggie_FilsAime_On_Garage_Devs_And_The_Value_Of_Software.php <comment><AUTHOR> It almost seems like the message is do you incubation on iOS / Android then you can talk to Nintendo. I think his band analogy works against his point.</comment>


Late Bronze Age Shipwreck Excavation - <AUTHOR> http://nauticalarch.org/projects/uluburun-late-bronze-age-shipwreck-excavation/ <comment><USER2> I recently read a really good book about the systems collapse that occurred towards the end of the Bronze Age. The book is "1177 BC: The Year Civilization Collapsed" [1]; it provides a vivid look into the ancient world, with some eerie parallels to our world today.

The Late Bronze Age was a fascinating time around the Mediterranean; there was extensive trade between Egypt, the Hittites, Minoans, Assyrians, Mitanni, and others; shades of "globalization" and a multi-cultural aesthetic had emerged, then it all came crashing down in the 12th century BCE.

[1] [https://www.amazon.com/1177-B-C-Civilization-Collapsed- Turni...](https://www.amazon.com/1177-B-C-Civilization-Collapsed- Turning/dp/0691140898)

<comment><USER3> Eric Cline, the author of that book, is also an entertaining speaker.

I recommend his 1h youtube talk about the bronze age & genesis of "1177 BC": [https://www.youtube.com/watch?v=hyry8mgXiTk](https://www.youtube.com/watch?v=hyry8mgXiTk)

<comment><USER4> Thanks for the link! (HN needs a fav feature)

</comment></comment></comment><comment><USER5> The Uluburun shipwreck is famous enough to have a Wikipedia page: [https://en.wikipedia.org/wiki/Uluburun_shipwreck](https://en.wikipedia.org/wiki/Uluburun_shipwreck)

</comment><comment><USER6> " _...more than 22,000 dives logged to depths in excess of 150 feet._ "

How many divers did they lose?

</comment><comment><USER7> I was lucky to meet the ex director of the _Musee Guimet_ by chance, and he explained to me that his career started on nautical sites in the Philippines.

</comment><comment><USER8> And we don't even know the name of the sponge diver who found this. The find should be named after them.</comment>


Phillips Exeter Academy Mathematics Course Materials - <AUTHOR> http://math.exeter.edu/dept/materials/index.html <comment><USER2> Well, I guess it's no surprise that the rot has set in even at Exeter. In many ways, my below average public school in the late '70s was more rigorous than this dog's breakfast, at least prior to the calculus (where I don't like the emphasis on "Working within contexts whenever possible...").

Note that the word "proof" doesn't appear until the very highest specific class; traditionally the geometry class after the first algebra class was where that was introduced.

Then again, if they're preparing students for Harvard, as of the late '80s the only math requirement there was to prove you could do algebra, according to a friend who took their honors calculus.

<comment><AUTHOR> So you think these are easy problems? What would be an example of a secondary math curriculum that is better?

<comment><USER2> Well, for starters, the old traditional one that focused on _math_ and not calculators (beyond graphing; being able to quickly turn an equation into a graph is useful, particularly for the calculus).

I personally found the Algebra I, Geometry and Algebra II sequence to be good. Algebra I teaches you symbolic math. Geometry teaches you geometry, analogs to algebra (the algebraic discoveries of the Greeks were done with geometry) and introduces you to formal math including proofs. Algebra II brings it all together with serious analytic geometry and more algebra (and hopefully includes matrices); you need a really strong foundation in both to master the calculus.

After that, _briefly_ do enough trig to be prepared for calculus (see related comment below) and finish up your pre-calculus ending with limits.

At that point I draw an arbitrary line ending secondary math, although of course that's not how it's done, especially in the rest of the world.

Things NOT to do:

Avoiding "drill and practice".

"hands-on labs that require [ Algebra I students ] to collect data, make conjectures, and draw conclusions"

Actually, their "ADVANCED INTEGRATED MATHEMATICS" doesn't sound at all bad, except that the binomial theorem is something you should have learned early in Algebra I. It probably is a _much_ better way to introduce trig, which it deadly dry and apparently pointless in the traditional sequence.

Back to the things that set off warning bells:

An "inductive approach to calculus".

"Working within contexts whenever possible" (the emphasis suggests to me that they aren't just doing the standard physics applications).

<comment><AUTHOR> _I personally found the Algebra I, Geometry and Algebra II sequence to be good._

What textbooks did you use to learn those subjects? If I remember correctly from other comments of yours, you went on to a rigorous quantitative major in college, right?

<comment><USER2> I'm sorry, but that was in the period of 1975-8, so there's not a chance in the world I could remember them. And I went on to be a Chemistry major at MIT ... but _everyone_ at MIT must pass the first four classes listed here: <http://news.ycombinator.com/item?id=1107911> (the calculus plus physics as of the 19th century).

My advice is to find older textbooks (used is cheap). Pre-calculator is good (cheap non-graphing calculators were available long before the graphing ones were), avoid New Math and all that like the plague (yes, set theory _is_ tremendously useful (and multiple bases even more for people like us), and I'm _very_ glad I started learning it in elementary school, but for 99% of students it's going to be a totally unmotivated distraction then (I was lucky I found it "neat" and simple to learn)).

Rainforest Math is _right out_ , as it anything that doesn't assume you've drilled your arithmetic tables until you know them cold.

People have said good things about the Singapore Math curriculum (<http://www.singaporemath.com/>) but I haven't really looked at it. Others like the Saxon math texts ([http://saxonpublishers.hmhco.com/en/saxonpublishers.htm;jses...](http://saxonpublishers.hmhco.com/en/saxonpublishers.htm;jsessionid=CDB48C7E0E7010591B28AE3BF45EE04F.ecom- app-wk2)), which integrate geometry throughout. Avoid _anything_ with manipulatives.

(Side note: _DO NOT_ try algebra based physics (generally taught as a US senior class); it's cargo cult science and _no one_ does it but "educators" and their victims. There's a reason Newton invented the integral calculus to figure out his system of mechanics.)

I've procured some texts to someday _relearn_ my math starting with Algebra; I can only vouch for the beginning of the first ones _and not for someone learning this for the first time_ ; I haven't touched in detail any beyond those two. If you're interested, just ask and I'll supply the list with ISBNs.

<comment><AUTHOR> _If you're interested, just ask and I'll supply the list with ISBNs._

I am interested, so I am asking here. I'm always interested in recommendations of math learning materials, because I am a math teacher by occupation now.

<comment><USER2> I'm working on the list (the annotations will take a while, and I'll probably post it section by section); watch this space, and I'll email you a copy as well.

</comment></comment></comment></comment></comment></comment></comment><comment><USER3> All of the links on that page give me a "system cannot find the file specified" error, except the Harkness one. I assume they were working four hours ago, based on the comments here ... (must resist urge to spout conspiracy theories). They were also working 18 months ago, for anyone who still wants to see them:

[http://web.archive.org/web/20080610161827/http://math.exeter...](http://web.archive.org/web/20080610161827/http://math.exeter.edu/dept/materials/index.html)

Anyway, based on the dates, I'm guessing this may be some kind of summer/remedial course, rather than their regular curriculum.

<comment><AUTHOR> I'm encountering the same error in not finding the files, which I had previously downloaded. Thanks for the helpful archive link.

As of the last revision date, those problem sets were the usual study materials for the main school year math courses at Exeter. Even very advanced students took the courses shown (depending on entry grade) before going on to other courses.</comment></comment>


Hiding the Real Africa : Why NGOs prefer bad news - <AUTHOR> http://www.cjr.org/reports/hiding_the_real_africa.php?page=all <comment><USER2> I wonder when Chinese manufacturing jobs will get moved to Africa? Underway by 2020?</comment>


Generate iconfonts from probably the largest premium vector icon set on the web - <AUTHOR> https://pictonic.co <comment><USER2> It looks very nice, but isn't this the wrong way to do vector graphics online? The purpose of a font as I see it is to give _text_ certain style. This looks like a hack - using one thing in a way it was not supposed to be used. Editing the source code of a web page using this must be very unintuitive. We have SVG and while it is far from perfect, at least it is supposed to represent pictures. And can use more than 1 color...

<comment><USER3> Theoretically you're right, but SVG doesn't work in IE, so it's not a realistic option for most developers. Icon fonts are scalable, retina-ready and actually work.

</comment></comment><comment><USER4> I'd like to see JavaScript code provided that is capable of drawing the same thing in a Canvas2D context. I can work with you on what that would look like.

(I'm the author of Blossom, an upgrade to SproutCore that does all UI elements in Canvas -- see <https://github.com/fohr/blossom.>)

UPDATE: Yes, I'm aware there are SVG converters out there. It's still annoying.

<comment><AUTHOR> Interesting, yea I guess that's exactly what would be required to achieve this, a function capable of reliably translating between path data formats and also canvas instructions. Path data can be annoying though, so many ways to express the same thing. Happy to collab on a jsfiddle? Once we have that the rest should be fairy simple.

<comment><USER4> I'd start with this and see what the output looks like: <http://www.professorcloud.com/svg-to-canvas/>

</comment></comment></comment><comment><USER5> Looks nice. Why do I have to log in to browse icons? There is the widget on the homepage that cycles through them but I can't actually get it to pause so I can see what's available. That's really annoying.

<comment><AUTHOR> hi there, i worked on pictonic. thanks for the feedback. the widget should pause on hover, i'll look into that. it only shows a small random sample from the full library though. since these are premium icons we have some terms and a non-public area

<comment><USER6> Don't use hover for that. First it is not obvious because it has no affordance and secondly it doesn't work on mobile.

<comment><AUTHOR> Good points, thanks

</comment></comment></comment></comment><comment><USER7> Looks cool. In the demo I would love to be able to change the font-size beyond 20-40 px as well as add a 2nd font with regular text to see how it looks next to that.

<comment><AUTHOR> Hiya, thanks for the feedback! what info would the comparison give? Did you want to compare kerning and baselines?

<comment><USER7> I just want to look at the source for something like your example image to see what you need to do to line up the icons with other fonts.

<comment><AUTHOR> ok thanks, we'll look into this, in the meantime, it should line up pretty nicely, and its easy to mod with css

</comment></comment></comment></comment><comment><USER8> Can I use icon fonts with native iOS apps?

<comment><USER6> They are standard fonts so if you can set the type, why not?

<comment><USER8> I ask because alz needs to know I care.

That, and I'm lazy. Which alz also needs to know.

<comment><AUTHOR> Thanks, this is really good feedback. We will definately look into it

<comment><AUTHOR> Btw We can also provide individual icon svgs with the font pack if this is useful

<comment><USER8> I'll get back to this when I get to overhauling the icons in my apps. Not sure when that is.

<comment><AUTHOR> hi there,

i just wanted to let you know that we've tested these on ios, and in an upcoming release we are going to make it a piece of cake to integrate pictonic's icons into your ios projects.

alan

</comment></comment></comment></comment></comment></comment></comment><comment><USER9> No github icon D:

<comment><AUTHOR> _facepalm_ ...we'll add this for sure</comment></comment>