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tokenadulton Algebra

Thanks for sharing this particular Feynman lecture. The treatment here, using what are basically the Peano postulates to derive the field properties of the real numbers and then the basic structure of secondary school mathematics, follows the treatment of Landau's Grundlagen der Analysis (Foundations of Analysis), a concise book that Feynman was probably aware of as he presented his lecture. Feynman of course added a sense of excitement and wonder that makes this lecture charming to read. Such treatments of the foundations of secondary school mathematics are fairly commonplace in the better university textbooks of mathematics. I first learned of Landau's book in a discussion of mathematics education in a Usenet newsgroup back in the 1990s, and bought the German edition on the recommendation of Michael Spivak's famous textbook Calculus, which follows a similar approach (but starting from the field properties of real numbers taken as axioms). In those days, I'm pretty sure, the standard calculus textbook at Caltech, where Feynman taught, was Apostol's textbook, which starts a little bit differently but also takes a theorem-proof approach.

https://maa.org/press/maa-reviews/calculus-4

tokenadulton Paper map sales are booming

My user experience on several recent trips is that Google Maps showed me the exit number for the exit I would use next very prominently on top of the display (where it shows the direction of the next turn). Maybe that isn't rolled out consistently for all trips.

tokenadulton So why a News Feed?

Post is currently a progressive web app. There is no immediate plan to build dedicated mobile apps for Post.

tokenadulton So why a News Feed?

To access Post on my desktop computer, I just any browser to navigate to Post [dot] news. It's just a website. I have stored cookies on one browser I use, and I typically start up that browser with Post as one default tab. I have another browser I use for testing websites that shows me what Post looks like to users who have never logged in.

https://post.news/

tokenadulton Waze Founder Noam Bardin is starting up a Twitter alternative

OP here. My apologies for the phrase "Twitter alternative" in the article title, which is NOT exactly Noam Bardin's vision for the Post startup.

I appreciate the comments here from HN users. I've hardly posted here in a long time, because in recent years I have posted mostly about politics, which is off-topic posting here on HN. A federated world of specialized online communities is an appealing idea, and I will be trying out the Fediverse as well. (A lifelong friend who is an infosec specialist has landed on a server about infosec, and that's probably where I will establish a lurker account, in the interest of being on a securely configured server.)

Information security in an online service is one of the features I look for, and why I prefer big, well invested commercial online services to home-brew solutions. I figure HN has enough back-end infrastructure to keep what data I share with HN safe, and Facebook does too. (One can dislike how Facebook allows advertisers to look at user data while still appreciating how Facebook keeps away certain kinds of criminal threat vectors.)

The user perception of the user experience ultimately decides what users think about online networks. Part of the user experience in any network is the other users. That's what I've long appreciated about HN. That's what I liked about Twitter as I took care to follow interesting people who post there. I'll see about the newest communities and who else is there, and decide based on my preferences as everyone else will.

Thanks again for the back-and-forth in the discussion here, which has been good food for thought.

tokenadulton Waze Founder Noam Bardin is starting up a Twitter alternative

The phrasing "Twitter alternative" is my fault in setting the title for the thread-opening post here. The "Twitter alternative" phrasing should not be attributed to the founder of Post.

I get the impression that the founder, Noam Bardin, DOESN'T think he's building a Twitter alternative but rather, in the beta welcome page's words, "a civil place to debate ideas; learn from experts, journalists, individual creators, and each other; converse freely; and have some fun. Many of today's ad-based platforms rely on capturing attention at any cost — sowing chaos in our society, amplifying the extremes, and muting the moderates. Post is designed to give the voice back to the sidelined majority; there are enough platforms for extremists, and we cannot relinquish the town square to them."

Twitter has never been quite like that. If the founder's vision succeeds, I might like Post very well indeed. In all such things, the proof is in the user experience as experienced by each user, but I think the goals sound good for Post.

tokenadulton Ask HN: If you were asked to design Mathematics courses

I would start by largely imitating the courses that already exist in the country of Singapore. They are pretty good examples of international best practice, and they are available in English, the language of school instruction in Singapore.

https://www.singaporemath.com/Singapore_Math_s/331.htm

tokenadulton Ask HN: Improving the world as a software developer

A good framework for looking at careers and figuring out if your best trade-off is to do your occupation as a direct way to make the world a better place or to make your living and then donate money to make the world a better place can be found in the book Doing Good Better: How Effective Altruism Can Help You Help Others, Do Work that Matters, and Make Smarter Choices about Giving Back by William MacAskill. In many ways, it is the best career planning advice I have ever seen in any book, and I'm applying for myself and encouraging my four children to use the same planning framework.

https://www.amazon.com/Doing-Good-Better-Effective-Altruism/...

tokenadulton 4,000-year-old termite mounds found in Brazil are visible from space

"The mounds, which are easily visible on Google Earth, are not nests."

This sentence from the article kindly submitted here ignores that Google Earth imagery includes imagery taken from airplanes as well as from satellites. Statements that such-and-such an object (a classic example is the Great Wall of China) is visible from space, or from the Moon, go back to eras long before human space flight. Most such statements are wrong.

As other comments previous to mine have noted, various specialized imaging devices in satellites (or on airplanes) can have a higher resolution than human-eye vision. But the headline "are visible from space" is surely an exaggeration. Space flight has been going on since 1960s, but there has been no report of the termite mounds till now, it appears.

tokenadulton In few years renewable power may become a better economic option

I hope there is further work on renewable aviation fuels, as vehicle fuels in general will be a big source of demand for fossil energy extraction for quite a while, and especially for aviation applications.

"Renewable energy in transport" report by IEA (.PDF)

https://www.iea.org/media/training/presentations/Day_2_Renew...

tokenadulton Ask HN: Good books on history of mathematics?

I like anything by John Stillwell about the history of mathematics. It's accessible (not QUITE as accessible as The Lady Tasting Tea) and interesting.

https://www.amazon.com/Elements-Mathematics-Euclid-John-Stil...

tokenadulton Best-selling introductory psychology books give misleading view of intelligence

I know eminent IQ researchers back at the time who declined invitations to sign on to the Gottfredson consensus statement (with good reason, in my opinion). On the other hand, it is still a reasonably fair statement of a lot of the consensus among IQ researchers, but as you say now twenty years out of date. (I read the consensus statement right after it was published.)

tokenadulton Best-selling introductory psychology books give misleading view of intelligence

Thanks for sharing that link. The underlying paper is (of course) better than the popular article kindly submitted to open the interesting discussion here. In particular, the paper makes clear its own methodological limitations.

tokenadulton Best-selling introductory psychology books give misleading view of intelligence

Gottfredson's paper is a paper that I have read, and I see it is being used as the analytical framework for criticizing psychology textbooks. I do research for writing popular writings on psychology, so I have a whole bunch of introductory psychology textbooks in the office where I am typing this, and I have to agree that introductory psychology textbooks leave a LOT to be desired in representing the consensus of modern psychology research. That's true about research on human intelligence and true about any other psychology topic: the introductory textbooks only do a so-so job.

That said, one might wonder where to find good information about current psychology research. Sometimes there are review articles that update practitioners on current research, which are incidentally read by scientists in other disciplines. I'll note for the record that not all psychologist agree EITHER with the review article I will link here, but it is a good readable account of current issues in the psychological research on human intelligence and well worth a read for Hacker News participants who are curious about these issues. It refers to many of the most important papers in the field, most of which I have read over the last three decades.

Nisbett, R. E., Aronson, J., Blair, C., Dickens, W., Flynn, J., Halpern, D. F., & Turkheimer, E. (2012). Intelligence: New findings and theoretical developments. American Psychologist, 67, 130-159. doi:10.1037/a0026699

(Disclaimer: I have met many of the researchers on human intelligence, including Gottfredson, at professional conferences, but my views of what the overall research says and who has the best leads on open research questions are my own.)

http://people.virginia.edu/~ent3c/papers2/Articles%20for%20O...

tokenadulton Mathematical secrets of ancient tablet unlocked after nearly a century of study

The part of the article that says, "Daniel Mansfield, of the university’s school of mathematics and statistics, described the tablet which may unlock some of their methods as 'a fascinating mathematical work that demonstrates undoubted genius' – with potential modern application because the base 60 used in calculations by the Babylonians permitted many more accurate fractions than the contemporary base 10" seems to be the basis for that subheadline. But that's ridiculous and shows that the editors of the article (not the quoted scholar, necessarily) are innumerate. (Common, whether proper or improper) fractions written in any numerical base are equally accurate--fractions are exact real numbers. Approximations of a fraction in a place-value notation can be made as accurate as needed with sufficient expressed place values, and since 500 years ago, the Western world has been able to write decimal numerals for rational numbers to any desired degree of accuracy.

tokenadulton There Was No ‘Golden Age’ of Air Travel

Air travel being priced so that you (not to mention I and anyone else) can enjoy it reasonably often seems to be a good thing, not a bad thing.

tokenadulton Storing Drinking-Water in Copper Pots Kills Contaminating Bacteria (2012)

What follow-up has there been on this since the 2012 publication in a rather obscure journal? Most importantly, is there a source of copper vessels in most countries that is as inexpensive as other means of reducing bacterial load in drinking water?

tokenadulton Scientists Tie 52 Genes to Human Intelligence

"But all of these genes together account for just a small percentage of the variation in intelligence test scores, the researchers found; each variant raises or lowers I.Q. by only a small fraction of a point.

'It means there’s a long way to go, and there are going to be a lot of other genes that are going to be important,' Dr. Posthuma said."

Indeed. This result is fully predictable from the several previous GWAS studies on IQ that have been done. Any gene that influences IQ in the general population has at most a small effect, and the variance among human individuals in IQ is the result of interaction of hundreds of genes and the environment the individual lives in.

Here's a link to a lot of good writings by one of the leading researchers on human behavior genetics, for more details. I especially like one particular article I'll link just below the link to his collected writings.

http://people.virginia.edu/~ent3c/vita1_turkheimer.htm

Turkheimer, E. (2000). Three laws of behavior genetics and what they mean. Current Directions in Psychological Science, 9, 160-164.

http://people.virginia.edu/~ent3c/papers2/Articles%20for%20O...

tokenadulton New Study Challenges a Genetic Link to Stress, Depression

The press release is misleading. Indeed, press releases about scientific studies are almost always misleading, which is why they are not the preferred source for stories about new scientific findings.

I participate most weeks during the United States school year in a "journal club" about human behavior genetics. The meetings include researchers who research genetic influences on depression and other mental disorders. It has been known for a LONG time that depression runs in families in a way that demonstrates genetic influence on depression. (In other words, adoption studies and twin studies, and especially studies on the rare monozygotic twins who are brought in separate households, make clear that genetic similarity of human individuals is linked to their similarity in risk for depression.) It has also been known for a LONG time that environmental influences, including the vague set of influences called "stress," matter for development of depression, so sometimes monozygotic ("identical") twins are discordant for depression, because they have different life experiences.

What the press release is about, and what scientists have been trying to figure out during my adult life, is what the nature of genetic influences on depression might be. It has also been known for the better of a decade, and suspected much earlier by the more astute researchers on human behavior genetics, that MANY genes influence any one human behavior trait of interest. Depression is SURELY, as we can now say by the results of massive genome-wide association studies (GWASs), influenced by hundreds of genes, each of which has only a small effect on risk. So the press release reports that an early finding that was expected to show that one gene variant had a lot to do with developing depressing has rather shown that that gene variant, as is true of all other gene variants, sometimes has no detectable effect on a patient's having depression or not.

The human mood regulation system is just that, a SYSTEM, so perturbations of many different aspects of the system can cause clinical signs that are identified as "depression." What helps depression, in general, is a both-and approach of prescribed medicine under the supervision of a physician and talk therapy provided by a psychotherapist. Most patients these days with diagnosed depressed do MUCH better than patients did a generation ago. Some patients are helped a lot by one or another of the selective serotonin reuptake inhibitors (SSRIs), and some are not helped by those medicines at all. And that's all because depression is a clinical condition with a diverse set of underlying biochemical causes, as we know for sure from GWAS studies.

Further study of genetic relationships to depression should help develop new drugs that help some patients who are not helped by current drugs or that help patients who are already helped by existing drugs but with fewer side effects. But we are NOWHERE near being able to use genetic test results to decide which drug to use first: patients have to talk to their doctors about how they are feeling as they undergo treatment. Your best bet for finding good treatment if you feel depressed is to find out what has helped a NEAR relative who has also suffered depression.

tokenadulton How Breaking the Rules Could Win You $250,000

The official prize program announcement from the sponsoring organization, the MIT Media Lab:

https://www.media.mit.edu/disobedience/

tokenadulton What a Century of Research Reveals About Gifted Kids

The thread-opening link here is a blog post by an active researcher on the topic. The blog post links to a recent paper from the Review of Educational Research[1] by a more senior researcher with more details. I have met both of these researchers at professional conferences.

[1] https://s3.amazonaws.com/vu-my/wp-content/uploads/sites/826/...

tokenadulton Ask HN: Online Security Tips for Newbie Freedom Activists?

Maybe some of the onlookers don't know that you have long identified yourself as a woman here. As I recall, we (you and I) eventually figured out that we first "met" on an online community before Hacker News was founded.

tokenadulton Ask HN: Online Security Tips for Newbie Freedom Activists?

Thank you very much to all for the detailed comments. I appreciate you keeping advice simple enough for someone like me, who decades ago counted as a "power user" of PCs, but who has no particular technical training or computer-related work experience. I will have to digest some of this advice for women (they are mostly women in the local group) who are barely comfortable using Facebook. And I'll pass on other tips to the women and men who have actual technical backgrounds and will be implementing the different online projects of the local group.

Advice that especially fits our situation is having an appropriate level of security for an intentionally PUBLIC organization whose members will be identifiable by multiple in-person activities in public places over the next few years. We are not afraid to be known as people who support the cause that we support. We are resolutely sticking to peaceful, legal means to reach our goals. Many group members are VERY wary of new group members--plenty of them are wary of me--so we will have to build mutual trust as we build mutual communication and public-facing communication. I like mz's advice to remind members that anything they say in an online group--even in our internal online groups for members only--might show up in mass media or in propaganda spread by opponents, so I try to model careful speaking and writing.

I'll link here to a document about the bad-case scenario of living under an actual dictatorship with a secret police force that kills political opponents. That's something I've actually done (in Taiwan, in the 1980s). The good news is that nonviolent popular movements can even overthrow dictators and establish democratic republics with full protection of civil liberties. That takes mental toughness, but it can be done. I've seen it done. You may be inspired by the document linked here and the other documents (in numerous languages) posted at the same website.

http://www.aeinstein.org/wp-content/uploads/2013/09/FDTD.pdf

tokenadulton Ask HN: Online Security Tips for Newbie Freedom Activists?

Thanks especially for items 8 through 15, which some people forget. Part of what I hope happens where I live is that 13 happens in a big way, and the overall inclusive movement becomes broader and broader as different specialized local groups network with one another and with a variety of national groups.

tokenadulton Paralyzed man regains use of arms and hands after experimental stem cell therapy

The patient's age being twenty-one may have made a difference in this happy news story. My dad had a slip and fall on ice at age seventy-two that left him paralyzed from the chin down until he died six years later. He had had a similar injury from a car crash (back when cars didn't have seat belts) at age eighteen, from which he recovered fully (although he wasn't so paralyzed from the first injury). So when he had his second injury, he at first thought he would also recover from that injury. Maybe because the second injury aggravated damage to his spine still remaining from his first injury, or maybe just because he was a lot older when injured the second time, he never recovered much at all from the second injury. His experience reminds me how many other people in a family are affected by spinal cord injuries, and thus how important it is to find better treatments for them.

So it's hard to say how wide a range of patients will be treatable with the new technique, but that's what medical research is for: to find out what helps for which patients. I hope further research continues on this and other treatments for spinal cord injuries.

tokenadulton A woman died from a superbug that outsmarted all 26 US antibiotics

This has been anticipated for a while (I recall posting comments about this years ago) as multiply antibiotic-resistant microbes have been spreading in India, where the woman mentioned in the article kindly submitted here had traveled.

http://blogs.wsj.com/indiarealtime/2013/04/23/india-has-lost...

https://www.nytimes.com/2014/12/04/world/asia/superbugs-kill...

tokenadulton The Riemann Hypothesis, explained

I like his wording of Euclid's classic proof of the infinity of prime numbers. That's good exposition to start off the article.

tokenadulton The Middle Class Can't Afford to Live in Cities Anymore

a decent home (2000 sq ft, good neighborhood, reasonable commute)

We have lived for more than a decade with four children in a house with fewer finished square feet of floor space. I'm curious about what "good neighborhood" means here, because my children can walk or bicycle all over the place, without fear of mishap, and the local public schools here draw people from all over the country. "Reasonable commute" is also a term I'd like to understand better in this context. How tied to location is the employment you each have, if you are able to move out of state?

I have to think that it's possible for middle-class people like my family (at a lower income level, currently, than what you self-report) to live in cities, because we do. Most of our work happens to be in outer-ring suburbs, so "reasonable commute" puts us there, but other people with work nearer into the center of the metropolitan area can live affordably further in.

Disclosure: we live in an other ring suburb of Minneapolis, just outside the beltway freeway around the Twin Cities, and barely within reach of the bus system. My wife and my third son bike-commute often, year-round.