Some links (Open Thread?)

It’s been quite a while since the last time I posted a ‘here’s some interesting stuff I’ve found online’-post, so I’ll do that now even though I actually don’t spend much time randomly looking around for interesting stuff online these days. I added some wikipedia links I’d saved for a ‘wikipedia articles of interest’-post because it usually takes quite a bit of time to write a standard wikipedia post (as it takes time to figure out what to include and what not to include in the coverage) and I figured that if I didn’t add those links here I’d never get around to blogging them.

i. Battle of Dyrrhachium. Found via this link, which has a lot of stuff.

ii. An AMA by someone who claims to have succeeded in faking his own death.

iii. I found this article about the so-called “Einstellung” effect in chess interesting. I’m however not sure how important this stuff really is. I don’t think it’s sub-optimal for a player to spend a significant amount of time in positions like the ones they analyzed on ideas that don’t work, because usually you’ll only have to spot one idea that does to win the game. It’s obvious that one can argue people spend ‘too much’ time looking for a winning combination in positions where by design no winning combinations exist, but the fact of the matter is that in positions where ‘familiar patterns’ pop up winning resources often do exist, and you don’t win games by overlooking those or by failing to spend time looking for them; occasional suboptimal moves in some contexts may be a reasonable price to pay for increasing your likelihood of finding/playing the best/winning moves when those do exist. Here’s a slightly related link dealing with the question of the potential number of games/moves in chess. Here’s a good wiki article about pawn structures, and here’s one about swindles in chess. I incidentally very recently became a member of the ICC, and I’m frankly impressed with the player pool – which is huge and includes some really strong players (players like Morozevich and Tomashevsky seem to play there regularly). Since I started out on the site I’ve already beaten 3 IMs in bullet and lost a game against Islandic GM Henrik Danielsen. The IMs I’ve beaten were far from the strongest players in the player pool, but in my experience you don’t get to play titled players nearly as often as that on other sites if you’re at my level.

iv. A picture of the Andromeda galaxy. A really big picture. Related link here.

v. You may already have seen this one, but in case you have not: A Philosopher Walks Into A Coffee Shop. More than one of these made me laugh out loud. If you like the post you should take a look at the comments as well, there are some brilliant ones there as well.

vi. Amdahl’s law.

vii. Eigendecomposition of a matrix. On a related note I’m currently reading Imboden and Pfenninger’s Introduction to Systems Analysis (which goodreads for some reason has listed under a wrong title, as the goodreads book title is really the subtitle of the book), and today I had a look at the wiki article on Jacobian matrices and determinants for that reason (the book is about as technical as you’d expect from a book with a title like that).

viii. If you’ve been wondering how I’ve found the quotes I’ve posted here on this blog (I’ve posted roughly 150 posts with quotes so far), links like these are very useful.

ix. Geology of the Yosemite area.

February 7, 2015 Posted by | Astronomy, Chess, Geology, History, Mathematics, Open Thread, Random stuff, Wikipedia | Leave a comment

Open Thread

It’s been a long time since I had one of these. Questions? Comments? Random observations?

I hate posting posts devoid of content, so here’s some random stuff:


If you think the stuff above is all fun and games I should note that the topic of chiralty, which is one of the things talked about in the lecture above, was actually covered in some detail in Gale’s book, which hardly is a book which spends a great deal of time talking about esoteric mathematical concepts. On a related note, the main reason why I have not blogged that book is incidentally that I lost all notes and highlights I’d made in the first 200 pages of the book when my computer broke down, and I just can’t face reading that book again simply in order to blog it. It’s a good book, with interesting stuff, and I may decide to blog it later, but I don’t feel like doing it at the moment; without highlights and notes it’s a real pain to blog a book, and right now it’s just not worth it to reread the book. Rereading books can be fun – I’ve incidentally been rereading Darwin lately and I may decide to blog this book soon; I imagine I might also choose to reread some of Asimov’s books before long – but it’s not much fun if you’re finding yourself having to do it simply because the computer deleted your work.

ii. Beyond Power Calculations: Assessing Type S (Sign) and Type M (Magnitude) Errors.

Here’s the abstract:

“Statistical power analysis provides the conventional approach to assess error rates when designing a research study. However, power analysis is flawed in that a narrow emphasis on statistical significance is placed as the primary focus of study design. In noisy, small-sample settings, statistically significant results can often be misleading. To help researchers address this problem in the context of their own studies, we recommend design calculations in which (a) the probability of an estimate being in the wrong direction (Type S [sign] error) and (b) the factor by which the magnitude of an effect might be overestimated (Type M [magnitude] error or exaggeration ratio) are estimated. We illustrate with examples from recent published research and discuss the largest challenge in a design calculation: coming up with reasonable estimates of plausible effect sizes based on external information.”

If a study has low power, you can get into a lot of trouble. Some problems are well known, others probably aren’t. A bit more from the paper:

“design calculations can reveal three problems:
1. Most obvious, a study with low power is unlikely to “succeed” in the sense of yielding a statistically significant result.
2. It is quite possible for a result to be significant at the 5% level — with a 95% confidence interval that entirely excludes zero — and for there to be a high chance, sometimes 40% or more, that this interval is on the wrong side of zero. Even sophisticated users of statistics can be unaware of this point — that the probability of a Type S error is not the same as the p value or significance level.[3]
3. Using statistical significance as a screener can lead researchers to drastically overestimate the magnitude of an effect (Button et al., 2013).

Design analysis can provide a clue about the importance of these problems in any particular case.”

“Statistics textbooks commonly give the advice that statistical significance is not the same as practical significance, often with examples in which an effect is clearly demonstrated but is very small […]. In many studies in psychology and medicine, however, the problem is the opposite: an estimate that is statistically significant but with such a large uncertainty that it provides essentially no information about the phenomenon of interest. […] There is a range of evidence to demonstrate that it remains the case that too many small studies are done and preferentially published when “significant.” We suggest that one reason for the continuing lack of real movement on this problem is the historic focus on power as a lever for ensuring statistical significance, with inadequate attention being paid to the difficulties of interpreting statistical significance in underpowered studies. Because insufficient attention has been paid to these issues, we believe that too many small studies are done and preferentially published when “significant.” There is a common misconception that if you happen to obtain statistical significance with low power, then you have achieved a particularly impressive feat, obtaining scientific success under difficult conditions.
However, that is incorrect if the goal is scientific understanding rather than (say) publication in a top journal. In fact, statistically significant results in a noisy setting are highly likely to be in the wrong direction and invariably overestimate the absolute values of any actual effect sizes, often by a substantial factor.”

iii. I’m sure most people who might be interested in following the match are already well aware that Anand and Carlsen are currently competing for the world chess championship, and I’m not going to talk about that match here. However I do want to mention to people interested in improving their chess that I recently came across this site, and that I quite like it. It only deals with endgames, but endgames are really important. If you don’t know much about endgames you may find the videos available here, here and here to be helpful.

iv. A link: Crosss Validated: “Cross Validated is a question and answer site for people interested in statistics, machine learning, data analysis, data mining, and data visualization.”

A friend recently told me about this resource. I knew about the existence of StackExchange, but I haven’t really spent much time there. These days I mostly stick to books and a few sites I already know about; I rarely look for new interesting stuff online. This also means you should not automatically assume I surely already know about X when you’re considering whether to tell me about X in an Open Thread.

November 18, 2014 Posted by | Chess, Lectures, Mathematics, Open Thread, Papers, Statistics | Leave a comment

Open Thread

It’s been a long time since I had one of these.

Some random stuff I’ve come across:

i. Reviews of Anything. Some pretty funny stuff there. Examples include:  Our solar system: 1 star. Reviews of this review. The 5 star Rating System: 9/10. Obese Americans, 1 out of 4. Spell Checker: 1 satr.


iii. The Bad Writing Contest. A quote from the link:

“The move from a structuralist account in which capital is understood to structure social relations in relatively homologous ways to a view of hegemony in which power relations are subject to repetition, convergence, and rearticulation brought the question of temporality into the thinking of structure, and marked a shift from a form of Althusserian theory that takes structural totalities as theoretical objects to one in which the insights into the contingent possibility of structure inaugurate a renewed conception of hegemony as bound up with the contingent sites and strategies of the rearticulation of power.”

In contexts where you socialize with people who write that way, dumbpiphanies may happen.


v. I’m not actually sure I liked this lecture very much (I was very much annoyed by the word ‘cristal’ in the slides in the last part of the lecture; he repeatedly misspells the word crystal in the slides. I find that kind of sloppiness irritating, because I tend to use the existence of spelling errors in lecture notes/slides in mathematical lectures as what might be termed a caution heuristic; if the lecturer did not bother to correct spelling errors, I figure he probably also didn’t bother to correct other errors in the slides – and if you start to think along the way that there might be errors in the slides, a lecture to me becomes less enjoyable to watch, especially when the lecture deals with complicated stuff which is hard enough to follow as it is), but I figured I might as well share it anyway:

vi. arXiv vs snarXiv.



September 30, 2014 Posted by | Lectures, Mathematics, Open Thread | 8 Comments

Meta/Open Thread

I dislike brief updates like these, but I figured it was better in this case to post it than to not post it. As I mentioned earlier, last week I did not have internet access – I am now back online. However I am also very exhausted and I have some things that need to get done (these ‘things’ include ‘sleep’) before I can justify spending the amount of time a regular blogpost takes me to write. I expected before going offline that I would be able to post something yesterday, but things did not go as planned.

I didn’t read much during the week I was offline, but I did manage to read Buskirk et al. and Yzerbyt et al., as well as a couple of Christie novels I have no intention of covering here on the blog – see my goodreads profile for details if you’re curious about those. I’ll not resume regular blogging until tomorrow afternoon/evening at the earliest, but things should after that return to normal quite soon.

As I don’t have a lot of stuff to contribute to the conversation at the moment, I thought it would be apposite to let this be an Open Thread as well. Questions, recommendations, random remarks, etc., are all welcome.

August 26, 2014 Posted by | Open Thread | Leave a comment

Open Thread

It’s been a while since I’ve posted one of these. This is where you share interesting stuff you’ve come across since the last time I posted one of these things (or perhaps it is where you don’t share interesting stuff; the latter is by far the most common decision, after all). I don’t really have anything interesting to share here myself, but I figured I should post something anyway, so… :

I was considering adding this lecture as well, but it’s not a particularly good lecture so that seemed like a bad idea.

A friend of mine recently made me aware of the existence of this resource, which one of two of you may consider to be worth checking out.

June 28, 2014 Posted by | Cancer/oncology, Lectures, Medicine, Music, Open Thread, Philosophy | 7 Comments

Open Thread

This is where you share interesting stuff you’ve come across since the last time I posted one of these.

I figured I should post a bit of content as well, so here we go:


(Chichen Itza is not located in ‘Southern America’, but aside from that I don’t have a lot of stuff to complain about in relation to that lecture. As I’ve mentioned before I generally like Crawford’s lectures.)

ii. I haven’t read this (yet? Maybe I won’t – I hate when articles are gated; even if I can usually get around that, I take this sort of approach to matters as a strong signal that the authors don’t really want me to read it in the first place (if they wanted me to read it, why would they make it so difficult for me to do so?)), but as it sort of conceptually relates to some of the work Boyd & Richerson talk about in their book, which I read some chapters of yesterday, I figured I should link to it anyway: Third-party punishment increases cooperation in children through (misaligned) expectations and conditional cooperation. Here’s the abstract:

“The human ability to establish cooperation, even in large groups of genetically unrelated strangers, depends upon the enforcement of cooperation norms. Third-party punishment is one important factor to explain high levels of cooperation among humans, although it is still somewhat disputed whether other animal species also use this mechanism for promoting cooperation. We study the effectiveness of third-party punishment to increase children’s cooperative behavior in a large-scale cooperation game. Based on an experiment with 1,120 children, aged 7 to 11 y, we find that the threat of third-party punishment more than doubles cooperation rates, despite the fact that children are rarely willing to execute costly punishment. We can show that the higher cooperation levels with third-party punishment are driven by two components. First, cooperation is a rational (expected payoff-maximizing) response to incorrect beliefs about the punishment behavior of third parties. Second, cooperation is a conditionally cooperative reaction to correct beliefs that third party punishment will increase a partner’s level of cooperation.”

I should note that I yesterday also started reading a book on conflict resolution which covers the behavioural patterns of social animals in some detail, and which actually also ‘sort of relate, a bit’ to this type of stuff. A lot of stuff that people do they do for different reasons than the ones they usually apply themselves to explain their behaviours (if they even bother to do that at all..), but scientists in many different areas of research are making progress in terms of finding out ‘what’s really going on’, and there are probably a lot more potentially useful approaches to these types of problems than most people usually imagine. Many smart people seem at this point to me to be familiar with some of the results of the heuristics-and-biases literature/approach to human behaviour because that stuff’s been popularized a lot over the last decade or two, and they probably have a tendency to interpret human behaviour using that sort of contextual framework, perhaps combined with the usual genes/environment-type conceptual approaches. Perhaps they combine that stuff with the approaches that are most common among people with their educational backgrounds (people with a medical degree may be prone to using biological models, an economist might perhaps apply game theory, and an evolutionary biologist might ask what a chimpanzee would have done). This isn’t a problem as such, but many people might do well to try to keep in mind every now and then that there are a lot other theoretical frameworks one might decide to apply in order to make sense of what humans do than the one(s) they usually apply themselves, and that some of these may actually add a lot information even if they’re much less well-known. Some of the methodological differences relate to levels of analysis (are we trying to understand one individual or a group of individuals?), but that’s far from the whole story. To take a different kind of example, it has turned out that animal models are actually really nice tools if you want to understand some of the details involved in addictive behaviours, and they seem to be useful if you want to deal with conflict resolution stuff as well, at least judging from the stuff I’ve read in that new book so far (one could of course consider animal models to be a subset of the genetic modeling framework, but in an applied context it makes a lot of sense to keep them separate from each other and to consider them to be distinct subfields…). I have a nagging suspicion that animal models may also be very useful when it comes to explaining various forms of what people usually refer to as ’emotional behaviours’, and that despite the fact that a lot of people tend to consider that kind of stuff ‘unanalyzable’, it probably isn’t if you use the right tools and ask the right questions. You don’t need to be a doctor or a biologist to see why hard-to-observe purely ‘biological effects’ having behavioural effects may be important, but are these sorts of dynamics taken sufficiently into account when people interact with each other? I’m not sure. Mathematical modeling approaches like the one above are other ways (of course various approaches can be combined, making this stuff even more complicated…) to proceed and they seem to me to be, certainly when they generate testable predictions, potentially useful a well – not necessarily always only because we learn whether the predictions are correct or not, but also because mathematical thinking in general allows/requires you to think more carefully about stuff  and identify relevant variables and pathways (but I’ve talked about this before).

I should point out that I wrote the passage above in part because very occasionally I encounter a Fan of The Hard Sciences (on the internet) who seems to think that rejecting all kinds of human behavioural theory/-research (‘Social Science’) on account of it not being Hard Enough to generate trustworthy inferences is a good way to go – I actually had a brief encounter with one of those not too long ago, which was part of what motivated me to write the stuff above (and the stuff below). That guy expressed the opinion that you’d learn more about human nature by reading a Dostoyevsky novel than you would by reading e.g. Leary & Hoyle’s textbook. I’m perhaps now being rather more blunt than I usually am, but I thought I should make it clear here, so that there are no misunderstandings, that I tend to consider people with that kind of approach to things to be clueless fools who don’t have any idea what they’re talking about. Perhaps I should also mention that I have in fact read both so I feel qualified to judge on the matter, but this is probably arguably besides the point; the disagreement goes much deeper than just the truth content of the specific statement in question, as the much bigger problem is the methodological divide. Some skepticism is often required in behavioural sciences, among other things because establishing causal inference is really hard in many areas, but if you want your skepticism to make sense and be taken seriously you need to know enough about the topic and potential problems to actually formulate a relevant and cogent criticism. In that context I emphasize that ‘unbundling’ is really important – if you’re speaking to someone who’s familiar with at least some part of ‘the field of social science’, criticizing ‘The Social Sciences’ in general terms will probably just make you look stupid unless you add a lot of caveats. That’s because it’s not one field. Do the same sort of problems arise when people evaluate genetic models of human behavioural variance and ‘sociological approaches’? Applied microeconomics? Attachment theory? Evolutionary biology? All of these areas, and many others, play some role and provide part of the picture as to why people behave the way they do. Quantum physics and cell biology are arguably closer connected than are some of the various subfields which might be categorized as belonging to ‘the field’ of ‘social science’. Disregarding this heterogeneity seems to be more common than I’d wish it was, as is ‘indiscriminatory skepticism’ (‘all SS is BS’). A problem with indiscriminatory skepticism of this sort is incidentally that it’s sort of self-perpetuating in a way; that approach to matters pretty much precludes you from ever learning anything about the topic, because anyone who has anything to teach you will think you’re a fool whom it’s not worth spending time talking to (certainly if they’re in a bad mood on account of having slept badly last night…). This dynamic may not seem problematic at all to people who think all SS is BS, but of course it might be worth pointing out to those kinds of people that by maintaining that sort of approach to the subject matter they’re probably also cutting themselves off from learning about research taking place in areas they hadn’t even considered to belong to the field of social science in the first place. Symptom analyses of medical problems are usually not considered to be research belonging to the social sciences, but that’s mostly just the result of a categorization convention; medical problems, or the absence of them, impact our social behaviours in all kinds of ways we’re often not aware of. Is it medical science when a doctor performs the analysis, but social science when the psychologist analyzes the same data? Is what that guy is doing social science or statistics? Sometimes the lines seem to get really blurry to me. Discriminatory skepticism is better (and probably justified, given methodological differences across areas), but contains its own host of problems. Often discriminatory skepticism seems to imply that you disregard certain levels of analysis completely – instead of ‘all SS i BS’, it becomes ‘all SS belonging to this level of analysis is BS’. Maybe that’s better than the most sensible alternative (‘perhaps it’s not all BS’) if the science is really bad, but even in those situations you’ll have contagion effects as well which may cause problems (‘culture? That’s the sort of crap cultural anthropologists deal with, isn’t it? Those people are full of crap. I’m not going to spend time on that stuff.’ So you disregard those aspects of behaviour completely, even if perhaps they do matter and can be subject to scientific analysis of a different type than the one the Assigned Bad Guys (‘Cultural Anthropologists’) usually apply).

I don’t think we’ll ever get to the point where we have a Big All-Encompassing Theory of How Humans Work because there are too many variables, but that does not mean that the analysis of specific behaviours and specific variables is without merit. Understanding that I may feel argumentative right now because I’ve misjudged my insulin requirements (or didn’t sleep enough, or haven’t had enough to eat, or had a fight with my mother yesterday, or…) is important knowledge to take into account, and you can add a lot of other similarly-useful observations to your toolbox if you spend some time on this type of stuff. A big problem with not doing the research is that not doing the research does not protect you from adopting faulty models – rather it seems to me that it almost guarantees that you do. Humans need explanations for why things happen, and ‘things that happen’ include social behaviours; they/we need causal models to make sense of the world, and having no good information will not stop them from coming up with theories about why people behave the way they do (social scientists realized that a while back..). And as a result of this, people might end up using a novel written 150 years ago to obtain insights into why humans behave the way they do, instead of perhaps relying on a textbook written last year containing the combined insights of hundreds of researchers who looked at these things in a lot of detail. The researchers might be wrong, sure, but even so this approach still seems … stupid. ‘I don’t trust the social scientists, so instead I’ll rely on the life lessons and social rules taught to me by my illiterate grandmother when I was a child.’ Or whatever. You can easily end up doing stuff like this, without ever even suspecting, much less realizing, that that’s what you’re doing.

Comments on the topics covered above are welcome, but I must admit that I didn’t really write this stuff to start a dicussion about these things – it was more of a, ‘this is where I’m coming from and these are some thoughts on this topic which I’ve had, and now you know’-posting.

iii. Enough lecturing. Let’s have a chess video. International Master Christof Sielecki recently played a tournament in Mallorca, and he’s made some excellent videos talking about his games. Here’s one of those videos:

I incidentally think I have learned quite a bit from watching his material on youtube. I may have talked about his youtube channel here on the blog before, but even if I have I don’t mind repeating myself as you should know about it if you’re interested in chess. He is one of the strongest players online providing this sort of content, and he provides a lot of content. If you’re a beginner some of his material may be beyond you, but not all of it; I don’t think his opening videos for example are particularly difficult to understand or follow, even if you’re not a very strong player. And if you’re a ‘strong club player’ I think this is the best chess channel on youtube.

May 25, 2014 Posted by | Astronomy, Chess, Lectures, Open Thread, Physics | 7 Comments

Open Thread

I was recently reminded that I probably ought to revive these things.

First a few ‘meta’ observations regarding content on this blog, then I’ll leave the word to you:

I was recently reminded of the fact that people sometimes read stuff I’ve written a long time ago (usually I try – mostly successfully – to put it out of my mind that this ever happens). So it’s worth pointing out two things here. First, if I wrote something 5 years ago, I’ve probably changed my mind about it at least three times since then. Very occasionally I will by accident realize that I’ve written something awful a long time ago, and if that happens I may decide to delete the post or make corrections to it; but usually that doesn’t happen, so there’s a lot of crud in the archives which I’ve simply neglected to get rid of because it takes a lot of time and effort dealing with that kind of stuff unless you just delete everything indiscriminately, a move I’ve been hesitant to make (perhaps with little justification). Secondly, if I just published a post (people who subscribe to the blog in one way or another will, as far as I’ve been made aware, usually be able to tell when a post was published) here on the blog and you’re reading it right after publication, there’s a high likelihood the post will change later on. I often feel a desire to make corrections and perhaps add stuff to or delete stuff from a post within the first hour or two of a post’s existence. If you only plan on reading a post once then reading it right after I published it might not be the optimal strategy as it’ll likely at that point still be a work in progress. The more words I’ve written on my own, the more likely it is that corrections will be made later on. Sometimes the time-lag between publication and correction can be significant, e.g. it sometimes happens that I post something before I go to bed and then make adjustments to the post the next day. Some people would probably argue that this procedural approach is inefficient and that I ought to finish the post, with corrections, before I publish it, but one reason why I’m not that careful about such things is that I consider most of the stuff published here to be relatively ‘fluid’ anyway; this isn’t a book, I always retain the right and the opportunity to correct errors, delete a paragraph or a post I don’t like, or really whatever strikes my fancy. If a few people happen to come across a few error-ridden and in retrospect only half-finished posts along the way, I don’t really mind that. Usually those errors will get corrected in time and thoughts will be developed in more (or, as the case may be, less) detail. I have considered how to approach major adjustments before – one option I’ve considered is to rename the posts and add a ‘revised’ in a parenthesis to the post title, perhaps with a little note at the beginning as well, in order to inform readers who’ve only read what later turned out to be an early draft that the post has changed – but I haven’t really found a solution I like. So for now it is the way it is. Feedback and ideas are welcome.

Okay, the word is yours. Read anything interesting?

May 4, 2014 Posted by | meta, Open Thread | 3 Comments

Open Thread

This is where new readers come out of the woodwork and say ‘hi!’ And it’s where regular readers tell me about interesting stuff they’ve come across since the last Open Thread.

I had social obligations this weekend and so I haven’t done a lot of blogging-relevant stuff over the last few days. I’ve read Ishiguro’s The Remains of the Day, and although I won’t blog it here I will note that it was an awesome book.

A few links:

i. I recently watched this lecture, but I decided against embedding it here because I was very far from impressed by it. If you decide to give it a shot you should at the very least do yourself a favour and skip the first 5 minutes. You should also note that quite a bit of work has been done in related areas such as search and matching theory since the Gale–Shapley algorithm was developed.

ii. Sexual Behavior, Sexual Attraction, and Sexual Identity in the United States: Data From the 2006–2008 National Survey of Family Growth.

Some results and data from the link:

“Among adults aged 25–44, about 98% of women and 97% of men ever had vaginal intercourse, 89% of women and 90% of men ever had oral sex with an opposite-sex partner, and 36% of women and 44% of men ever had anal sex with an opposite-sex partner. Twice as many women aged 25–44 (12%) reported any same-sex contact in their lifetimes compared with men (5.8%). Among teenagers aged 15–19, 7% of females and 9% of males have had oral sex with an opposite-sex partner, but no vaginal intercourse.”

“About one-half of all STIs occur among persons aged 15–24”

“Although current HIV medications have substantially increased life expectancy (7), the medical costs are substantial, averaging approximately $20,000 per year for each person in care”

“Among women aged 15–44 in the 2006–2008 NSFG, 11% had never had any form of sexual activity with a male partner in their lives, 6.1% had sex in their lifetime but had no opposite-sex sexual activity in the past 12 months, and 69% had one male partner in the past 12 months. Nearly 8% had two partners in the past year, and about 5% had three or more partners in the past year. […] Among women aged 25–44, 1.6% never had any form of sexual activity with a male partner, 6.6% have had sex with a male but not in the past year, and 82% had one partner in the past year. Having one partner in the past 12 months was more common at older ages, presumably because more of these women are married. Having one partner in the past year was significantly more common among married (97%) or cohabiting (86%) women than those in other groups […] women aged 22–44 with less than a high school diploma were nearly twice as likely (13%) to have had two or more partners in the past 12 months as women with a bachelor’s degree or higher (7%).”

“Among women aged 15–44, the median number of male partners is 3.2 and in 2002 it was essentially the same at 3.3. For men aged 15–44, the median number of female partners was 5.6 in 2002 and remained similar at 5.1 in 2006–2008. As in 2002 when 23% of men and 9% of women reported 15 or more partners in their lifetimes, men were more likely than women to report 15 or more partners in 2006–2008 (21% of men and 8% of women). […] These results are consistent with prior findings from surveys in the United States and other countries, which all show that men on average report higher numbers of opposite-sex sexual partners than do women of the same age range […] While 11%–12% of women with lower levels of education reported 15 or more partners, 6.8% with bachelor’s degrees or higher reported 15 or more partners. For men […], the disparity by college education was smaller”

iii. The FIDE Candidates Tournament (the tournament deciding who’s to play against Magnus Carlsen in the next World Chess Championship match) has begun and a few rounds have been played. Some interesting chess so far. The official site is here. I haven’t followed the live commentary, but I’ve noted that the main commentators seem to be Danish Grandmaster Peter Heine Nielsen and his wife Viktorija Čmilytė (currently the 12th strongest female player in the world). Without having followed the coverage I can’t of course say how well they’ve done, but I’d say that picking someone like Nielsen to provide commentary seems to me like a very good idea; aside from being a ‘pretty strong player’ who’s been in the world top 100 for a decade or something like that, he’s also been one of Anand’s seconds for years – he’s currently Magnus Carlsen’s second – and if you want someone able to talk about the specific details of the various openings likely to be employed in games like these, it would probably be very hard to find someone significantly better than him.

March 17, 2014 Posted by | Open Thread | 5 Comments

Open Thread

A little bit of stuff from around the web:

i. “Most people lack the motivation and self-discipline to teach themselves entirely new subjects while sitting alone at their computers. “Will I ever need this? Will I ever be asked to prove I know this? Will anyone ever be impressed by my knowing this? Will anyone I care about care if I don’t know it?” If the answer to any of these questions ever seems like it might be “no”, boom, window closed, game over. Or rather game on. Time for some XBox!”

Quote from the comment section of this post, where the main topic is MOOCs. I wrote some comments related to that quote, but later decided not to post the stuff I’d written – but I figured I might as well post the original quote and include the link here.

ii. Too Fat to Fit through the Door: First Evidence for Disturbed Body-Scaled Action in Anorexia Nervosa during Locomotion.

“To date, research on the disturbed experience of body size in Anorexia Nervosa (AN) mainly focused on the conscious perceptual level (i.e. body image). Here we investigated whether these disturbances extend to body schema: an unconscious, action-related representation of the body. AN patients (n = 19) and healthy controls (HC; n = 20) were compared on body-scaled action. Participants walked through door-like openings varying in width while performing a diversion task. AN patients and HC differed in the largest opening width for which they started rotating their shoulders to fit through. AN patients started rotating for openings 40% wider than their own shoulders, while HC started rotating for apertures only 25% wider than their shoulders. The results imply abnormalities in AN even at the level of the unconscious, action oriented body schema. Body representation disturbances in AN are thus more pervasive than previously assumed: They do not only affect (conscious) cognition and perception, but (unconscious) actions as well.”

Much more at the link.

iii. I posted Zach Weiner’s video earlier, but this one is pretty good too:

iv. A chess game I played recently. In related news (?), Magnus Carlsen has started a youtube channel:

Sorry for the infrequent blogging – I don’t have a good excuse so you can just ascribe it to lack of motivation and self-discipline (see above). On a more serious note I have been working a lot and I have not been feeling particularly great. This comic actually for a short while made me seriously consider if it would be worth it to deliberately gain 20-30 kg just in order to cut a decade or two off my life expectancy; the associated costs seemed a lot lower to me than they usually are for other people, and there would be benefits as well – although it’s hardly a good coping device, food is certainly better than quite a few of the alternatives (e.g. alcohol, hard drugs).

I should note that if people don’t at least occasionally add links/comments/reading suggestions/questions etc. to these posts, I’ll consider retiring the Open Threads again. On a related matter I like it when people provide feedback via the rating system, but people rarely use this feature.

February 8, 2014 Posted by | Open Thread | 2 Comments

Open Thread

A little random stuff from the web:

1914 alt(link)

I felt pretty much that way after watching the video below and skimming parts of Terence Tao’s related blogpost.

I did a little work on infinite series and their convergence properties in a previous course in micro – enough to know that this stuff sometimes makes no sense at all – but I do not think I have ever seen this one before. Incidentally I should point out that if you ever get the impression that you have a tendency to overestimate your own intellectual abilities and you would like an easy way to keep reminding yourself that you’re not actually that smart, making Tao’s blog your starting page for a couple of weeks should do the trick…

ii. A couple of Khan Academy videos (just to remind you guys that the site is still around and still has a lot of videos you may be interested in watching at some point):

iii. A few interesting wikipedia links from the bookmarks (I can’t be bothered to write a ‘wikipedia links of interest post’):
Empire of Japan.
Juan Perón.
Operation Keelhaul.
Project MKUltra.
List of animals with fraudulent diplomas.

iv. After the end of the last chess tournament I participated in I got curious as to how strong the opponents I’m regularly playing against on playchess actually are, so I decided to for a while semi-systematically look up the ratings of the players I play against to get an idea how well I actually do. I got curious to a significant degree because despite a rather horrible end of the aforementioned tournament (½ out of 4 in the last four games), I still performed at ~1900 FIDE, which is far higher than the playing strength I had assumed based on my online games/rating. There may be multiple explanations for this, for one thing ‘over-the-board chess is different’. But another aspect may play a role as well: What I realized when I started ‘checking out’ my opponents was that a lot of strong players have online ratings not that different from my own (I defeated all these players in online games during the last month or so). Of course lots of opponents didn’t have fide ratings, and lots of players don’t add their true names to their profiles, but this little exercise did make me realize that I may not actually be doing that badly on the site.

I recently found out how to share games I’ve played on playchess, making the game sharing process significantly easier than it used to be. I may share more games in the future than I have in the past. Here are two games I played in January: 1, 2. On a related matter, here’s one reason why I’ll probably never become an IM. Despite the fact that I’m most of the time on the top 100 tactics list on playchess, I feel pretty confident I’ll never find a mate like that in one minute.

v. Am I the only one thinking this is way too much work to be worth the effort? Also: 88 dates? A mathematician like him should be familiar with the literature on optimal stopping rules (see e.g. this), and from my reading of the article it doesn’t seem as if he even considered implemented a stopping rule.

January 30, 2014 Posted by | Chess, History, Khan Academy, Lectures, Mathematics, Medicine, Open Thread | Leave a comment

Open Thread

Exam’s getting close – expect no further updates until Monday or Tuesday. Some random stuff of interest from the bookmarks:

i. First a very neat link: The Cost-Effectiveness Analysis Registry. It’s exactly what it says on the tin; a registry with information about cost-effectiveness stuff.

I really like the utility weight feature. And of course I was curious about my own disease so I looked up T1DM. According to the search I did, a utility weight estimate for ‘Diabetes with no complications’ is reported to be 0.757. One way to think about this is to say that that person’s life is about three-quarters as good as a healthy person’s life. Another way to think about it is that if person X gets type 1 diabetes during, say, the first year of life (pretty close to my situation), the lifetime utility loss that individual will incur from that diagnosis corresponds to losing two decades of his/her life (i.e. ‘die at the age of 56 instead of at the age of 75’, assuming ‘equivalent’ age-related (and other) utility variation in the two populations). With complications the utility weights of course drop further; diabetes + retinopathy yields a weight of 0.61, and nephropathy + heart disease equals 0.516 (‘his life is only half as good as that of a healthy person’). Of course one should have in mind that the utility contribution from complications impact fewer years of life because people with heart disease or kidney failure have a tendency to die at faster rates than people who do not suffer from these complications (certainly part of why the utility weights are lower…), and some people live many years without complications.

I’d say that if one wants a brief overview of how ‘severe’ a disease is thought to be the utility weight estimates provided at the site are actually really nice tools, but do have in mind that a lot of assumptions go into making such estimates, and there are lots of differences in treatment regimes and/or differences in disease impacts e.g. when you make cross-country comparisons (most estimates are not ‘globally valid’, it’s safe to say). ‘Proper’ utility weights are/ought to be highly heterogenous across subgroups, and will in many cases (not just when it comes to diabetes) be time-dependent, among other things. Individual variation is huge. In a way this is all a bit ‘quick and dirty’, but it’s better than nothing; either way it’s probably a good idea to check out the actual studies if you want more than just a quick estimate. Of course the site has as already mentioned stuff other than utility weight estimates – if you want to know if a given health intervention is likely to be cost-effective this also seems like a great place to start. (And on a related note, if you know nothing about cost-effectiveness analysis a good place to start would be to read this book, or at least the first half of it.)

ii. Being right or being happy: pilot study; a ‘study’ from the Christmas edition of the British Medical Journal. I’m sure some of you have already read this, but others may not have. Here’s the introduction (I should note that it’s not a very long ‘article’):

“Three of the authors are general practitioners who see many patients and couples who lead unnecessarily stressful lives by wanting to be right rather than happy. Mathieu encourages her psychotherapy clients “to try to live in the gray. There are a million shades of gray” (although a recent erotic novel suggests there are only 50) “on the spectrum of white to black, and each provides a much richer telling of a story that is hardly ever as clear as this or that. So, when we looked a bit more closely, we saw that ‘right versus happy’ was not so much about getting crowned the winner or loser, a genius or fool; it was more about flawed thinking and a desire to want to feel being in control.”1 This might be the first study to systematically assess whether it is better to be right than happy; a Medline search in May 2013 found no similar articles. Our null hypothesis was that it is better to be right than happy.”

I’m skeptical about the results…

iii.  Who did whom? A field guide to Pleistocene hookups, by John Hawks.

iv. At this point I’m roughly one-third of the way towards reaching the level of ‘walking dictionary’ on (give it another month or two…). Many of the roughly 1700 words I’ve supposedly mastered on the site I already knew – considering how little I’ve focused on this stuff over the years, I’m actually quite surprised now how many words I ‘sort of know, but didn’t know that I knew’. On the other hand there have also been quite a few words I’ve never seen before, and some words I didn’t know as well as I thought I did. A funny thing about language, which I haven’t really thought about, is that like in the case of other areas of knowledge you’ll often not ever actually be made aware of the fact that your vocabulary (/knowledge) is limited unless you make an effort of actively seeking out words (facts) you don’t know; if you don’t know that there’s a word for X, you’ll often never be made aware that you didn’t know – especially if other people don’t know that word either. The ‘hey, I’m familiar with this concept but I didn’t know it actually had a name…’-experience a site like this will occasionally provide is really nice. Anyway, below a few words I’ve picked up along the way:

Eleemosynary (of, relating to, or supported by charity; charitable).
Martinet (a person who is very strict and demands obedience from others; a strict disciplinarian; a person who stresses a rigid adherence to the details of forms and methods).
Ratiocination (the process of exact thinking: reasoning; a reasoned train of thought).
Sagaciousness (the ability to understand inner qualities or relationships; having or showing acute mental discernment and keen practical sense; shrewd).
Sententious (having or expessing strong opinions about what people should and should not do; given to or abounding in aphoristic expression/excessive moralizing; terse, aphoristic, or moralistic in expression).
Solecism (an ungrammatical combination of words in a sentence; something deviating from the proper, normal, or accepted order; a breach of etiquette or decorum).
Echolalia ((psychiatry) mechanical and meaningless repetition of the words of another person; an infant’s repetition of sounds uttered by others).
Ingenuous (lacking in sophistication or worldliness; innocent and unsuspecting).
Ineluctable (not to be avoided, changed, or resisted; inevitable).
Supererogatory (more than is needed, desired, or required; superfluous).

Note that even if you’re an incorrigible reprobate who hates other people and don’t really want to learn new stuff, a larger vocabulary will be something you can make good use of; a larger vocabulary makes it a lot easier to surreptiously insult people. Rather than calling the overweight woman in front of you fat, you can just call her embonpoint. And instead of calling the moron next to you in the bar an alcoholic, you can just say that he’s bibulous…


This is awesome! (And actually that hypothesis probably sounds more plausible than at least some of the ‘evolutionary theories’ I’ve seen presented (in earnest) in the past…)

Your turn – what have you been doing? Comments to the stuff above? Any new readers out there who’d like to tell us a bit about themselves? Any good books or links I should read (after my exam)?

January 11, 2014 Posted by | Anthropology, Diabetes, Economics, Evolutionary biology, Health Economics, Medicine, Open Thread | Leave a comment


It’s 2014 and I’m still alive. Thought you should know.

I’ve decided not to stop blogging, but I’ll probably blog less in the time to come than I have in the past.

Consider this the first Open Thread of the new year. I’ll probably post a few posts soon with some actual content.

January 1, 2014 Posted by | Open Thread | 7 Comments

Open Thread

Share whatever you like – links, books, christmas present ideas (I’m planning on giving that whole thing a miss, but I’m not the only one reading the comments), …

My contributions to the discussion below:

i. Alcohol may not just be bad for the fetuses that make it out of the birth canal:

“Of the 186 pregnancies, 131 resulted in delivery of a child, and 55 (30 percent) were spontaneously aborted. Of the abortions, 34 were detected only by urinary hCG before or at 6 completed gestational weeks. The 21 clinically recognized abortions occurred in the interval after 6 and by 15 completed gestational weeks.

A high intake of alcohol by women or their partners was associated with a higher frequency of spontaneous abortions than was a low intake (table 1). Women who experienced a spontaneous abortion were older and had, on average, longer menstrual cycles, a higher caffeine intake, and partners with a higher caffeine intake than did women who gave birth (table 1). No association was found between spontaneous abortion and the partner’s smoking habits, partner’s age, body mass index, and partner’s reproductive illnesses; contraception last used; education for both man and woman; or hours at work for both partners.

The crude associations between female and male alcohol intakes and spontaneous abortion shown in figures 1 and 2 changed only slightly by adjustment for the confounders listed in table 2. Female alcohol intake was associated with a 2–3 times higher adjusted risk of spontaneous abortion compared with no intake, and male intake was associated with a 2–5 times increase in the adjusted risk. However, only the relative risks for male and female intakes of 10 or more drinks/week compared with no intake were statistically significant. We found a high correlation between male and female alcohol intakes. Additional adjustment for male intake revealed a lower risk of spontaneous abortion associated with female alcohol intake, whereas the higher risk associated with a high male alcohol intake changed only slightly following adjustment for female intake […] women in this study with a moderate or high alcohol intake [also] have an increased waiting time to pregnancy”

The quotes above are from Alcohol Consumption at the Time of Conception and Spontaneous Abortion, by Henriksen, Hjollund et al.

ii. Half of US clinical trials go unpublished.

I should note that I don’t know enough about this stuff to comment intelligently on the findings. I’m planning to read Principles and Practice of Clinical Trial Medicine at some point in the not-too-distant future, and so I figured I ought to wait until I have had a go at that book to comment on this stuff. I wanted to add the link anyway though, in part so that I’d remember it in case it’ll be a while until I read Chin & Lee’s book.

iii. On a more personal note, Monday evening I beat an International Master for the first time in my life. It was in a one-minute bullet game (each player gets one minute to play the entire game) so it was not a particularly well played game, but I consider this to be a somewhat significant milestone still – IMs are really good chess players (‘An International Master is usually in the top 0.25% of all tournament players at the time he or she receives the title’ – from the wiki-link above). My opponent was Migchiel De Jong – here’s his Fide profile, here’s the game. There’s incidentally no doubt this was the guy I played – his full name is on his profile and his blitz rating was above 2600 when I played him (which is high – higher than some GMs on the site). It wasn’t a case of me getting outplayed but winning on time anyway – rather I had a mate in one in the game which he spotted after he’d made his move, and he resigned as a consequence of spotting the mate even though I missed it. When he resigned he had only 0.3 seconds left on his clock, so this may have been a contributing factor; if he’d not resigned he’d have lost on time. I had 3.6 seconds left which was of course the main reason why I didn’t spot the mate – I was too busy making moves in the time scramble in order not to lose on time to look for mates.. The time-trouble was incidentally also of course the reason why I was only up a piece when he resigned and why I did not take his queen when he blundered it a few moves earlier (bullet-chess can get pretty wild…).

(Your turn…)

December 4, 2013 Posted by | Chess, Medicine, Open Thread, Personal, Studies | 12 Comments

Open Thread

i. Some questions:

“Look for reasons for living and internal strengths for managing risk:
* ‘What’s important to you in your life?’
* ‘What do you feel connected to? Faith? Family? Community?’
* ‘What keeps you going?’
* ‘Do you have a sense of purpose or meaning?’
* ‘How do you manage stress?’
* ‘What do you do to take care of yourself?’
* ‘What has kept you from killing yourself?’
* ‘What do you do that helps you deal with thoughts of suicide?’
* ‘How do you manage to stay safe?’
* ‘What would keep you from killing yourself now?’”

(From Chehil’s book)

ii. Detecting Consciousness in the Vegetative. An interesting post.



From this collection of hilarious Chinese translation fails (via Razib Khan – re. RK, see also this). Curious though I’d be about how the fries would deliver the baby, I don’t really need an emergency C-section at this point. And I’m not quite willing to let go of what’s left of my inner child yet. So I’d probably go for the fried cat ear.

iv. When I grow up, I want to be a cartoonist. In other words, a mathematician. On a related matter, comics like this (and this – don’t miss the votey at the red button!) almost make me sad I won’t have children. I should perhaps point out that SMBC in general is a pure goldmine when it comes to such comics – see for instance also this, this, this, this, this, this, this and this. The best I can hope for is probably something like this.

What’s going on in your life? What have you learned recently? Links of interest? How would you answer Chehil’s questions?

November 25, 2013 Posted by | comics, Open Thread, Random stuff | 5 Comments

Open Thread

i. A while back I promised an update on the clinical trial I’ve been enrolled in, but I forgot about that stuff. Anyway I have learned that I was one of the patients who got the active drug, and they’d like me to continue taking the drug for another two years. I’ve decided to stay in the trial (technically I’m enrolling in a new trial, but…) and keep taking the drug.

ii. Given that the World Chess Championship has just started, this paper about chess ratings seems timely. Here’s incidentally the World Chess Championship main site. It’s started out with two draws, the last of them lasting only one hour and fifteen minutes or so – really disappointing but perhaps not that surprising; most championship match games tend in my opinion to be rather boring.

iii. This weekend I went to a Mensa ‘Game Day’ meetup – basically we got together and played various games (mostly board-games in my case, but no chess..) the entire day. This is one of the few ways I’m currently trying to step outside my comfort zone. It was sort of an okay experience and I’m glad I gave it a shot. But I did get bored towards the end and I felt very drained afterwards. I learned that this kind of thing is an inefficient way to get to know people. I was reminded that when you feel socially isolated and lonely you tend to think of social interaction with other people as much nicer than it actually often is in real life.


Sorry for the infrequent updates. What have you been up to? Read something interesting? Watched a good movie?

November 12, 2013 Posted by | Astronomy, Chess, Open Thread, Papers, Personal | 6 Comments

Open Thread

i. Here are my thoughts on the upcoming Danish election:

(And here are my thoughts on voting in general.)

ii. Excerpt from Samuel Pepys’ diary (Friday the 19th of October, 1660):

Office in the morning. This morning my dining-room was finished with green serge hanging and gilt leather, which is very handsome.

This morning Hacker and Axtell were hanged and quartered, as the rest are.

This night I sat up late to make up my accounts ready against to-morrow for my Lord. I found him to be above 80l. in my debt, which is a good sight, and I bless God for it.”

Here’s a background article. I learned about the existence of this diary through Bryson. I should point out that navigation is easier at the site where the diary is located; you can get brief explanations of key terms simply by hovering over the linked words, and so you often don’t really need to click any links.


I don’t actually think the lecture is all that great, but I watched it anyway and I figured I might as well blog it.

iv. I got a draw against a ~2050 Elo opponent last Monday – you can watch the game here, I was white. This was actually I game I was reasonably satisfied with – my opponent was the one who offered the draw, which was in itself a small victory (I graciously accepted). The draw was not a result of a blunder in a time scramble or something like that; I played semi-accurate moves and so did my opponent, and so we ended up in a dead drawn position. I didn’t exactly play ambitiously in this game but with opponents like this most people will probably consider a draw a satisfactory outcome (my opponent was in the top 25 in the last Danish Championship), and keeping it simple seemed the best strategy, especially as I got completely crushed in the first game I played against him. Today I won a bullet game against a much stronger opponent, but I often do that and those games don’t really count nearly as much as these; games like this one are serious games, and in these kinds of time controls it seems I can still play along with some of the best players in the club. This is nice. After 8 games of the tournament my performance rating is now slightly above 1950.

Okay – on to you guys: What have you been up to? Have you read anything during the last couple of weeks that I ought to read as well? Have you seen an amazing TV series I’ve never heard about? A good online lecture? Found an amazing website?

This is probably also a good place for a new reader to step forward and tell me a little about yourself. I like to know at least a little bit about who’s reading along here.

October 28, 2013 Posted by | Chess, Economics, Health Economics, History, Lectures, Medicine, Open Thread | 11 Comments