# Econstudentlog

## Stuff

i. Econometric methods for causal evaluation of education policies and practices: a non-technical guide. This one is ‘work-related’; in one of my courses I’m writing a paper and this working paper is one (of many) of the sources I’m planning on using. Most of the papers I work with are unfortunately not freely available online, which is part of why I haven’t linked to them here on the blog.

I should note that there are no equations in this paper, so you should focus on the words ‘a non-technical guide’ rather than the words ‘econometric methods’ in the title – I think this is a very readable paper for the non-expert as well. I should of course also note that I have worked with most of these methods in a lot more detail, and that without the math it’s very hard to understand the details and really know what’s going on e.g. when applying such methods – or related methods such as IV methods on panel data, a topic which was covered in another class just a few weeks ago but which is not covered in this paper.

This is a place to start if you want to know something about applied econometric methods, particularly if you want to know how they’re used in the field of educational economics, and especially if you don’t have a strong background in stats or math. It should be noted that some of the methods covered see wide-spread use in other areas of economics as well; IV is widely used, and the difference-in-differences estimator have seen a lot of applications in health economics.

ii. Regulating the Way to Obesity: Unintended Consequences of Limiting Sugary Drink Sizes. The law of unintended consequences strikes again.

You could argue with some of the assumptions made here (e.g. that prices (/oz) remain constant) but I’m not sure the findings are that sensitive to that assumption, and without an explicit model of the pricing mechanism at work it’s mostly guesswork anyway.

iii. A discussion about the neurobiology of memory. Razib Khan posted a short part of the video recently, so I decided to watch it today. A few relevant wikipedia links: Memory, Dead reckoning, Hebbian theory, Caenorhabditis elegans. I’m skeptical, but I agree with one commenter who put it this way: “I know darn well I’m too ignorant to decide whether Randy is possibly right, or almost certainly wrong — yet I found this interesting all the way through.” I also agree with another commenter who mentioned that it’d have been useful for Gallistel to go into details about the differences between short term and long term memory and how these differences relate to the problem at hand.

“An extensive body of prior research indicates an association between emotion and moral judgment. In the present study, we characterized the predictive power of specific aspects of emotional processing (e.g., empathic concern versus personal distress) for different kinds of moral responders (e.g., utilitarian versus non-utilitarian). Across three large independent participant samples, using three distinct pairs of moral scenarios, we observed a highly specific and consistent pattern of effects. First, moral judgment was uniquely associated with a measure of empathy but unrelated to any of the demographic or cultural variables tested, including age, gender, education, as well as differences in “moral knowledge” and religiosity. Second, within the complex domain of empathy, utilitarian judgment was consistently predicted only by empathic concern, an emotional component of empathic responding. In particular, participants who consistently delivered utilitarian responses for both personal and impersonal dilemmas showed significantly reduced empathic concern, relative to participants who delivered non-utilitarian responses for one or both dilemmas. By contrast, participants who consistently delivered non-utilitarian responses on both dilemmas did not score especially high on empathic concern or any other aspect of empathic responding.”

In case you were wondering, the difference hasn’t got anything to do with a difference in the ability to ‘see things from the other guy’s point of view’: “the current study demonstrates that utilitarian responders may be as capable at perspective taking as non-utilitarian responders. As such, utilitarian moral judgment appears to be specifically associated with a diminished affective reactivity to the emotions of others (empathic concern) that is independent of one’s ability for perspective taking”.

On a small sidenote, I’m not really sure I get the authors at all – one of the questions they ask in the paper’s last part is whether ‘utilitarians are simply antisocial?’ This is such a stupid way to frame this I don’t even know how to begin to respond; I mean, utilitarians make better decisions that save more lives, and that’s consistent with them being antisocial? I should think the ‘social’ thing to do would be to save as many lives as possible. Dead people aren’t very social, and when your actions cause more people to die they also decrease the scope for future social interaction.

v. Lastly, some Khan Academy videos:

(This one may be very hard to understand if you haven’t covered this stuff before, but I figured I might as well post it here. If you don’t know e.g. what myosin and actin is you probably won’t get much out of this video. If you don’t watch it, this part of what’s covered is probably the most important part to take away from it.)

It’s been a long time since I checked out the Brit Cruise information theory playlist, and I was happy to learn that he’s updated it and added some more stuff. I like the way he combines historical stuff with a ‘how does it actually work, and how did people realize that’s how it works’ approach – learning how people figured out stuff is to me sometimes just as fascinating as learning what they figured out:

(Relevant wikipedia links: Leyden jar, Electrostatic generator, Semaphore line. Cruise’ play with the cat and the amber may look funny, but there’s a point to it: “The Greek word for amber is ηλεκτρον (“elektron”) and is the origin of the word “electricity”.” – from the first link).

(Relevant wikipedia links: Galvanometer, Morse code)

April 14, 2013

## Khan Academy videos of interest

I assume that not all of the five videos below are equally easy to understand for people who’ve not watched the previous ones in the various relevant playlists, but this is the stuff I’ve been watching lately and you should know where to look by now if something isn’t perfectly clear. I incidentally covered some relevant background material previously on the blog – if concepts from chemistry like ‘oxidation states’ are a bit far away, a couple of the videos in that post may be helpful.

I stopped caring much when I reached the 1 million mark (until they introduced the Kepler badge – then I started caring a little again until I’d gotten that one), but I noticed today that I’m at this point almost at the 1,5 million energy points mark (1.487.776). I’ve watched approximately 400 videos at the site by now.

Here’s a semi-related link with some good news: Khan Academy Launches First State-Wide Pilot In Idaho.

March 7, 2013 Posted by | biology, Khan Academy, knowledge sharing | 2 Comments

## Khan Academy videos of interest

Took me a minute to solve without hints. I had to scribble a few numbers down (like Khan does in the video), but you should be able to handle it without hints. (Actually I think some of the earlier brainteasers on the playlist are harder than this one and that some of the later ones are easier, but it’s a while since I saw the first ones.)

Much more here.

Naturally this is from the computer science section.

It’s been a while since I’ve last been to Khan Academy – it seems that these days they have an entire section about influenza.

## Khan Academy videos of interest

There are other ressources than Khan Academy out there, so I thought I’d start out with a few remarks related to those. I’m about to start a course on coursera which I signed up for a long time ago, but I’m actually reconsidering now because I may not be able to find the time. If you don’t know about the site, go have a look around. A friend of mine also linked to this collection of videos from MIT on Electricity and Magnetism – looks very interesting. Anyway, a few Khan Academy videos below:

Just how sensitive blood flow is to vessel radius is an aspect I’d never given much thought, even though this is not exactly the first time I’ve done work on fluid dynamics (there’s also a largish section on that at Khan Academy) or the cardiovascular system. For some reason this video really made that link much more obvious to me, and these dynamics make it easier in my mind to understand why even relatively small changes in blood vessel composition over time can actually impede blood flow quite significantly and turn out to have rather large physiological effects. Math far more often than not helps me to think more clearly about stuff.

Some other videos:

It’s been a while since I’ve been to Khan Academy (actually getting the Kepler badge sort of killed my motivation for a while), but I revisited the site earlier today and I realized that they’ve launched a brand new computer science section which looks really neat. Intro video below:

## Khaaan!

Here’s what the profile looks like now:

The topics are (still) all mathematics-related, and there are currently 345 individual skills in which one can obtain mastery. So having 300 below the belt means that I’ve pretty much cleaned out most major sections (each of the 19 challenge patches above basically required complete mastery of all exercises in the given topic).

I find it interesting that the incentive system of Khan Academy apparently seem to be so effective on me, considering how hard it is for me on a general level to do what I’d consider ‘real work’. I’m still not sure how much of it is the badge/achievements system and how much is other stuff; but I do know that when I study ‘in real life’, I get zero feedback on my performance or skill level for months. Feedback is basically what you get after you’ve sat your exams – twice a year or so. Sometimes there’s a bit more than that, but not much. If it’s possible and realistic to do this somehow (I know that some people argue that it is; by involving other people as well, putting money on the line etc.), it seems like it would be optimal for me to set up similar incentive systems for other areas of my life.

On the other hand, part of what makes Khan Academy’s system work so well on me is probably exactly that doing nothing any given day has zero consequenses for me; the punishment element/aspect is completely absent, so I always feel a (/false) sense of achievement after I’ve done work there. But if I had a third hand, I’d probably add to that that I’ve not actually spent all that much time at the site (compared to how much time is required to put in to get through a normal semester at a university). So I’m likely overestimating the relevant effect sizes.

Either way, the people at Khan Academy have done a lot of things – succesfully, I’d add – to make learning new stuff fun. If you haven’t already, you should make a profile and start learning. I’m willing to bet you don’t know everything that’s covered on the site.

## More ‘stuff’

i. (click images to view them in full size)

ii. Ed Yong has written a good piece about Kawaoka et al.’s study on bird flu mutations. I think you’ll learn more from Ed’s piece than from the actual study, but I wouldn’t know as I have only but very briefly skimmed the study.

iii. Ben Goldacre: Battling bad science. Ben Goldacre’s TED talk.

iv. A quote by Mencius Moldbug: “in many ways nonsense is a more effective organizing tool than the truth. Anyone can believe in the truth. To believe in nonsense is an unforgeable demonstration of loyalty. It serves as a political uniform. And if you have a uniform, you have an army.” I seem to recall having said something very much along the same lines quite a few times in the past. But it’s worth repeating. Direct link here, via lesswrong.

v. So, lately I’ve been reading Heather. I know I should have long finished the book by now, but I don’t seem to have been able to put in more than a few hours here and there lately, and it’s a very long book so I’m not quite done yet. It doesn’t help that I’m actually studying the book, instead of ‘just reading’ it; I don’t seem to be able to achieve much more than 20-25 pages/hour. I really like it though, and I hope to finish it later this week. Here’s a good quote from the concluding remarks of chapter 6, on Franks and Anglo-Saxons:

“there are many ways in which Frankish and Anglo-Saxon migration illustrate and develop the main themes of this book. Transport logistics [...] and active fields of information decisively shaped both, but perhaps above all it is again the interaction of migration and patterns of development, and the huge role played by prevailing political structures, that jump out of the evidence. Frankish and Anglo-Saxon migration can be seen as mechanisms by which unequal patterns of development were renegotiated. Despite its own economic transformations during the Roman era, non-Roman western Europe lagged sufficiently far behind adjacent areas of the Empire for the latter’s wealth to exercise a strong pull. [...] The main way for most outsiders to access any of this wealth [...] was to raid it regularly for movables, apart from a relatively few who made it big in the Roman army. Throughout the Roman period, this greater wealth was protected by armies and fortifications. As lowland Britain and north-eastern Gaul fell out of central imperial control at different points in the fifth century, however, the restriction these imperial institutions had imposed upon the capacity of outside populations to seize control of capital assets was removed, and raiding, after a time lag, turned into predatory migration, aiming at the seizure of landed estates.
Unequal development was ultimately responsible, then, for both flows of migration. But both the Frankish and the Anglo-Saxon versions were effect, rather than cause, of central Roman collapse. They played a major role in dismantling such structures of local Roman provincial life as remained upon their arrival in northern Gaul and Britain, respectively, but in both cases it was the failure of the imperial centre’s capacity to maintain enough force on its fringes that exposed these provincial Roman societies to immigrant attention.”

vi. Via Big Think, a few graphs and a few stats:

“Did you know that almost 90% of the world’s population lives in the northern hemisphere? And that half of all Earthlings [1] reside north of 27°N? Or that the average human lives at 24 degrees from the equator – either to its north or south?” (here’s a related post of mine)

viii. A Yale lecture – Demographic Transition in Europe; Fertility Decline:

x. The people at 23andMe (the name should be familiar to people reading gnxp) have made some videos on ‘human prehistory’ and on ‘genetics 101′ which are now available at Khan Academy. I’ve posted the ones on human prehistory below, you can watch the genetics videos here.

If nobody clicks the link to the biology section above where one can watch the Genetics 101 videos, I’ll probably blog those too at a later point in time. I know that there are a lot of links in this post, but you shouldn’t miss those either.

xi. Binary star.

xii. Transform fault.

May 3, 2012

## Random stuff from the net, links, wikipedia…

1. RAND: Living Well at the End of Life (via Razib Khan). Here’s a link to one of the sources, a book which deals with some of the same questions: Approaching Death: Improving Care at the End of Life. Looks interesting, don’t have time to read it at the moment.

2. Fatal familial insomnia. “Fatal familial insomnia (FFI) is a very rare autosomal dominant inherited prion disease of the brain. It is almost always caused by a mutation to the protein PrPC, but can also develop spontaneously in patients with a non-inherited mutation variant called sporadic Fatal Insomnia (sFI). FFI is an incurable disease, involving progressively worsening insomnia, which leads to hallucinations, delirium, and confusional states like that of dementia.[1] The average survival span for patients diagnosed with FFI after the onset of symptoms is 18 months.”

Sleep’s important.

“In psychology, the false consensus effect is a cognitive bias whereby a person tends to overestimate how much other people agree with him or her. There is a tendency for people to assume that their own opinions, beliefs, preferences, values and habits are ‘normal’ and that others also think the same way that they do.[1] This cognitive bias tends to lead to the perception of a consensus that does not exist, a ‘false consensus’. This false consensus is significant because it increases self-esteem. The need to be “normal” and fit in with other people is underlined by a desire to conform and be liked by others in a social environment.

Within the realm of personality psychology, the false consensus effect does not have significant effects. This is because the false consensus effect relies heavily on the social environment and how a person interprets this environment. Instead of looking at situational attributions, personality psychology evaluates a person with dispositional attributions, making the false consensus effect relatively irrelevant in that domain. Therefore, a person’s personality potentially could affect the degree that the person relies on false consensus effect, but not the existence of such a trait.

The false consensus effect is not necessarily restricted to cases where people believe that their values are shared by the majority. The false consensus effect is also evidenced when people overestimate the extent of their particular belief is correlated with the belief of others. Thus, fundamentalists do not necessarily believe that the majority of people share their views, but their estimates of the number of people who share their point of view will tend to exceed the actual number.

This bias is especially prevalent in group settings where one thinks the collective opinion of their own group matches that of the larger population. Since the members of a group reach a consensus and rarely encounter those who dispute it, they tend to believe that everybody thinks the same way.

Additionally, when confronted with evidence that a consensus does not exist, people often assume that those who do not agree with them are defective in some way.[2] There is no single cause for this cognitive bias; the availability heuristic and self-serving bias have been suggested as at least partial underlying factors.

The false consensus effect can be contrasted with pluralistic ignorance, an error in which people privately disapprove but publicly support what seems to be the majority view (regarding a norm or belief), when the majority in fact shares their (private) disapproval. While the false consensus effect leads people to wrongly believe that they agree with the majority (when the majority, in fact, openly disagrees with them), the pluralistic ignorance effect leads people to wrongly believe that they disagree with the majority (when the majority, in fact, covertly agrees with them).”

4. Malthus, An Essay on the Principle of Population. Salman Khan recently made a video on the subject, here’s wikipedia.

“Only a few decades ago, it was legal for a man to rape his wife. Sweden was the first country to explicitly criminalize it in 1965, and it has only been illegal in all fifty US states since 1993. Fifty-three countries around the world still don’t consider it a crime.

In some old patriarchal systems, a woman belonged first to her father (or closest living male relative if the father was dead) and then to her husband. Once married — and in some systems she could be married off without her consent to some old man she despised or had never met — her husband had a legal and “moral” right to her body whether she liked it or not. It gets even creepier when the bride is underage.”

We tend to take a lot of stuff for granted. Another reason why you should read Nothing To Envy.

“A schema (pl. schemata or schemas), in psychology and cognitive science, describes any of several concepts including:

*An organized pattern of thought or behavior.
*A structured cluster of pre-conceived ideas.
*A mental structure that represents some aspect of the world.
*A specific knowledge structure or cognitive representation of the self.
*A mental framework centering on a specific theme, that helps us to organize social information.
*Structures that organize our knowledge and assumptions about something and are used for interpreting and processing information.

A schema for oneself is called a “self schema”. Schemata for other people are called “person schemata”. Schemata for roles or occupations are called “role schemata”, and schemata for events or situations are called “event schemata” (or scripts).

Schemata influence our attention, as we are more likely to notice things that fit into our schema. If something contradicts our schema, it may be encoded or interpreted as an exception or as unique. Thus, schemata are prone to distortion. They influence what we look for in a situation. They have a tendency to remain unchanged, even in the face of contradictory information. We are inclined to place people who do not fit our schema in a “special” or “different” category, rather than to consider the possibility that our schema may be faulty. As a result of schemata, we might act in such a way that actually causes our expectations to come true.”

7. Koch Snowflake Fractal (a structure with infinite perimeter but a finite area). Couldn’t remember if I’ve already blogged this at one point, but no harm done in case I have:

January 3, 2012

## Khan Academy videos of interest

(I know there’s been a lot of video posts recently, this is almost turning into a vlog, but…)

Some additional data: I’ve previously blogged a Danish version of the ‘health care spending as a percentage of GDP’ -graph, going back to ~ 1970. The title is in Danish but it really shouldn’t be much of a problem for non-Danish speaking readers to figure out what’s going on:

November 7, 2011

## Random stuff

i. Perhaps most ‘imposter-syndrome’ sufferers are really imposters who do not suffer from imposter-syndrome. Convoluted? Well:

“Social psychologists have studied what they call the impostor phenomenon since at least the 1970s, when a pair of therapists at Georgia State University used the phrase to describe the internal experience of a group of high-achieving women who had a secret sense they were not as capable as others thought. Since then researchers have documented such fears in adults of all ages, as well as adolescents.

Their findings have veered well away from the original conception of impostorism as a reflection of an anxious personality or a cultural stereotype. Feelings of phoniness appear to alter people’s goals in unexpected ways and may also protect them against subconscious self-delusions.

Questionnaires measuring impostor fears ask people how much they agree with statements like these: “At times, I feel my success has been due to some kind of luck.” “I can give the impression that I’m more competent than I really am.” “If I’m to receive a promotion of some kind, I hesitate to tell others until it’s an accomplished fact.”

Researchers have found, as expected, that people who score highly on such scales tend to be less confident, more moody and rattled by performance anxieties than those who score lower. [...]

In short, the researchers concluded, many self-styled impostors are phony phonies: they adopt self-deprecation as a social strategy, consciously or not, and are secretly more confident than they let on.

“Particularly when people think that they might not be able to live up to others’ views of them, they may maintain that they are not as good as other people think,” Dr. Mark Leary, the lead author, wrote in an e-mail message. “In this way, they lower others’ expectations — and get credit for being humble.”

In a study published in September, Rory O’Brien McElwee and Tricia Yurak of Rowan University in Glassboro, N.J., had 253 students take an exhaustive battery of tests assessing how people present themselves in public. They found that psychologically speaking, impostorism looked a lot more like a self-presentation strategy than a personality trait.”

My emphasis, and here’s the link. The interesting thing to me is why exceeding expectations for a given accomplishment level is status-enhancing compared to doing worse than expected. Anyway, this is one of the many ways that people who pretend to be humble brag – by downplaying expectations they increase the status level associated with any given accomplishment-level. Very few people would consider employing a strategy aimed at improving expectations-forming mechanisms to better match reality in the long run a status-enhancing move.

ii.

Calvin: “I say it’s a fallacy that kids need 12 years of school! Three months is plenty!”
Calvin: “Look at me. I’m smart! I don’t need 11½ more years of school! It’s a complete waste of my time!”
Hobbes: “How on Earth did you get all the way to the bus stop with both feet through one pant leg?”
Calvin: “I fell down a lot.”
Hobbes: “Nothing. I was just curious.”

Calvin: “Look at all these ants.”
Calvin: “They’re all running like mad, working tirelessly all day, never stopping, never resting.”
Calvin: “And for what? To build a tiny little hill of sand that could be wiped out at any moment! All their work could be for nothing, and yet they keep on building. They never give up!”
Hobbes: “I suppose there’s a lesson in that.”
Calvin: “Yeah … Ants are morons. Let’s see what’s on TV.”

Calvin: “Tigers don’t worry about much, do they?”
Hobbes: “Nope.”
Hobbes: “That’s one of the perks of being feral.”
Calvin: “I’m not having enough fun right now.”
Hobbes: “You’re not?”
Calvin: “I’m just having a little bit of fun. I should be having lots of fun.”
Calvin: “It’s Sunday. I’ve just got a few precious hours of freedom left before I have to go to school tomorrow.”
Calvin: “Between now and bedtime, I have to squeeze all the fun possible out of every minute! I don’t want to waste a second of liberty!”
Calvin: “Each moment I should be able to say, “I’m having the time of my life right now!’”
Calvin: “But here I am, and I’m not having the time of my life! Valuable minutes are disappearing forever, even as we speak! We’ve got to have more fun! C’mon!”
[Calvin and Hobbes start running away]
Hobbes: “I didn’t realize fun was so much work.”
Calvin: “Sure! When you’re serious about having fun, it’s not much fun at all.”

When I was a child, I sometimes felt like Calvin did in that last comic. I never do anymore. I guess it’s part of growing up. Reading a strip like this once you have is a good way to make you remember that here is something you’ve probably lost for ever. I have read a lot of Calvin and Hobbes over the last couple of days. I really love that comic but sometimes reading it really hurts. Some of it is a lot deeper than it lets on.

iii.

I tweeted this, but in case you missed it: Khan Academy have now added Art History to the list of subjects covered. 300 videos of it. I don’t know how many of my readers have an interest in that stuff (I don’t), but if you do – go knock yourself out! They write in the blogpost that: “we are incredibly excited to push the frontier on freely available content in the Arts and Humanities.” And I’m excited about that too. People really shold not be paying a lot of money for this kind of stuff. Maybe if it’s available for free online – and presented at a site including other stuff as well, such as mathematics, physics ect., more young people will start to realize that…

October 20, 2011

## The French Revolution and The Napoleonic Wars

Wikipedia has some relevant stuff here, here and here. Note that if you’re interested in the history of France, Wikipedia has a ‘History of France series’ with lots of other stuff (see the sidebar in the article on the French Revolution).

Khan Academy has a lot of good stuff on the subject too, I’ve decided to post some of the videos here:

A comment before I move on to the Napoleonic Wars: Something I didn’t know anything about was that even though the Bastille did work as a political prison at the time, the prisoners really were nowhere near the main reason for storming it – the protesters stormed it to get hold of the weapons stored inside:

“On the morning of 14 July 1789, the city of Paris was in a state of alarm. The demonstrators, led by Amaria Cahila of the third estate in France, had earlier stormed the Hôtel des Invalides to gather arms (29,000 to 32,000 muskets, but without powder or shot), and were mainly seeking to acquire the large quantities of arms and ammunition stored at the Bastille. On the 14th there were over 13,600 kilograms (30,000 lb) of gunpowder stored there.

At this point, the Bastille was nearly empty of prisoners, housing only seven old men annoyed by all the disturbance:[4] four forgers, two “lunatics” and one “deviant” aristocrat, the comte de Solages (the Marquis de Sade had been transferred out ten days earlier). The cost of maintaining a medieval fortress and garrison for so limited a purpose had led to a decision being taken to close it, shortly before the disturbances began. It was, however, a symbol of royal tyranny.”

(More here)

September 10, 2011

## Khan Academy stuff of interest

September 3, 2011

## Some basic stuff (mostly for the non-economists)

As a student of “economics”, I’m pretty sure I’ve had more courses dealing with stuff like this (and of course stuff a bit harder) than I’ve had courses about how ‘the economy’ supposedly ‘works’.

In related news, semester started yesterday so I might update a bit less frequently in the time to come. We’ll see how it goes.

August 31, 2011

Some videos of interest:

August 17, 2011 Posted by | biology, Khan Academy, knowledge sharing | 2 Comments

## Khan videos of interest

Some of the stuff I’ve been watching today:

(For the record: I think the above video is just plain cool. I’ve had real trouble ‘getting’ how the kidneys actually work, despite reading quite a bit about that subject at one point; one of the main things I remember from reading about it when I did was that the more details were added to the mix the more confused I tended to get (always a risk when you use peer-reviewed research to supplement wikipedia and similar sources). Khan does a brilliant job here, he’s of course simplifying stuff somewhat but you get it.)

In a couple of later videos he makes a few clarifications regarding the terminology (and frankly if you like this one, you should watch them too – this one is the next in the series) but those are not super important.

The last two were some of the videos I felt I had to take a closer look at in order to get a little more out of some of the sections in the Microbiology textbook. I’m pretty sure this stuff was covered in HS-chemistry, but that’s a long time ago and I haven’t used that stuff since then so a lot of it is just gone. Thanks to Khan, brushing up on some of this stuff is a lot easier than it otherwise could have been.

I think I ought to have a go at the calculus section and linear algebra at some point, but so far I haven’t really found the motivation to do so – besides from watching a few random videos along the way. Incidentally, today I crossed the 100-completed-videos mark (75 of them were in the Cosmology and Astronomy section, which I’ve watched in full from start to finish – and which I highly recommend even though technically some of the videos probably do not belong in this category at all).

August 7, 2011

## Why do continental plates move around?

Don’t want the blog to die, even temporarily, so a brief update:

Here’s more, plus links to related stuff. There are lots of geology subjects covered in the Cosmology/Astronomy section of Khan Academy and it’s good stuff to get refreshed.. Or learn.

In other news, my brothers will be joining me and my parents tomorrow. Burial will take place on Friday. Today has been much better than yesterday and the day before, probably in part because the day was filled with stuff to do. Time helps. ‘Doing stuff’ helps.

July 19, 2011

## An introduction to DNA

I decided to take the biology stuff ‘from the top‘ and this is as far as I’ll go today:

…This is pure gold. I’m currenty at chapter 9 in Russell’s Genetics…, which is about ‘The Organization of DNA in Chromosomes’, after having read the chapter about ‘The Structure of Genetic Material’ (‘the chemical composition of DNA and RNA’). So I can tell you that Sal’s treatment is, as he also mentions himself again and again, grossly simplified – some of this is very complex stuff. However ‘the basics’ needn’t be that hard to get, and Salman Khan does his best to make this stuff approachable, even to people with very little knowledge of biology.

Today’s been a great day where I feel like I’ve learned a lot. If you’ve liked (some of..?) the videos I’ve posted from Khan Academy so far, then you really should go make a user profile (one can log in via google or facebook) and start exploring more systematically. There’s a lot of good stuff here.

July 12, 2011 Posted by | biology, Khan Academy | 10 Comments

## Krebs / Citric Acid Cycle (yep, Khanacademy’s still awesome!)

Lots more here. I also took a personal interest in this short but neat and instructive video:

He also has a couple of follow-ups to that one here, here and here. They are also quite neat; a lot of learning in a short amount of time.

Btw, I just went and made myself an account to Khanacademy. I consider it quite likely that I’ll visit the site more frequently in the future than I used to do. If I do I’ll do my best to remember to post on my progress here as well.

The site has a lot of data on your progress and I like that kind of stuff. For instance now I know that I’ve spent 50 minutes today on the site (maybe information like that could potentially cause me to cut down on my time consumption of a good like this, but I actually don’t think that is in any way the most likely outcome..).

## Euler’s formula and Euler’s identity

The video is more than half-way through the calculus coursework, so if you’re unfamiliar with this stuff there’ll probably be some things you don’t understand even if he keeps it simple and don’t go through a more formal proof. The Maclaurin series he’s talking about is just a Taylor series evaluated at x=0, at uni we always call them Taylor series or Taylor expansions but apparently naming conventions differ.

The three videos before that one builds up to this, but if you’re familiar with maths and can remember how to do Taylor expansions and how to deal with trigonometric functions, you should be able to follow this quite easily without watching those as well; I could, as he doesn’t deal with anything here that I haven’t had exams in at a previous point in time. It probably didn’t do any harm that I read 100 pages in Discrete Mathematical Structures this weekend, parts of which contained a brush-up on permutations and factorials (the “!”-thingies in the formulas).

Videos like these were the kind of stuff I had to cut down on a lot during the last month leading up to the exam, those and non-study books. I’m behind on the blogging of the books I’m reading but I’ll get to it.

What do economists learn when taking their education? Most people would probably guess that they/we learn a lot of stuff about markets, industries/firms and some political economy (‘how the economy works’) and such. Maybe something about ‘how to calculate the numbers’. This is another side of the coin. Even though we wouldn’t be asked to go through that proof at an exam, we are (at least some of us) probably expected to know enough math to be able to understand something like this (it depends on the courses). There’s a lot of math and statistics in (some areas of) economics. There’s actually enough to make a guy who voluntarily decides to watch a video like the one above in his spare time think it’s a little too much. Though of course part of the reason why I feel that way is the fact that I suck at math, which is also why I try to get better at it – at least I’m not a math atheist. Now that we are dealing with comics, there’s also this.

June 22, 2011

## A video

The previous video in the series, which he mentions a few times, is here. And of course there’s a lot more here, under the ‘Biology’ section.

November 11, 2010