Econstudentlog

‘Get a friend – live longer’

No, that’s not actually what the study says but I’m sure that’s what the headlines will sound like when the journalists get their hands on this study…

“Across 148 studies (308,849 participants), the random effects weighted average effect size was OR = 1.50 (95% CI 1.42 to 1.59), indicating a 50% increased likelihood of survival for participants with stronger social relationships. This finding remained consistent across age, sex, initial health status, cause of death, and follow-up period.”

[…]

“social relationships were more predictive of the risk of death in studies that considered complex measurements of social integration than in studies that considered simple evaluations such as marital status.”

Here’s a link to the study. The estimated effects of social relationsships on mortality are, in case you were in doubt, huge:

“These findings indicate that the influence of social relationships on the risk of death are comparable with well-established risk factors for mortality such as smoking and alcohol consumption and exceed the influence of other risk factors such as physical inactivity and obesity. Furthermore, the overall effect of social relationships on mortality reported in this meta-analysis might be an underestimate, because many of the studies used simple single-item measures of social isolation rather than a complex measurement.”

July 29, 2010 Posted by | data, health, studies | 1 Comment

An expensive mind

“Finally, there is also a distinguishing feature that is a much more remarkable violation of expectations – a brain three times the size expected of a primate our size. This is all the more interesting as primates are already twice as encephalized as other mammals […] A direct comparison shows this difference in numbers: Whereas human brains have an average volume of 1251.8 cubic centimetres and weigh about 1300 gram, the brains of the other great apes only have an average volume of 316.7 cubic centimetres and weigh between 350-500 gram”

[…]

“The human brain is also extremely “expensive tissue” (Aiello & Wheeler 1995): Although it only accounts for 2% of an adult’s body weight, it accounts for 20-25% of an adult’s resting oxygen and energy intake (Attwell & Laughlin 2001: 1143). In early life, the brain even makes up for up 60-70% of the body’s total energy requirements. A chimpanzee’s brain, in comparison, only consumes about 8-9% of its resting metabolism (Aiello & Wells 2002: 330). The human brain’s energy demands are about 8 to 10 times higher than those of skeletal muscles (Dunbar & Shultz 2007: 1344), and, in terms of energy consumption, it is equal to the rate of energy consumed by leg muscles of a marathon runner when running (Attwell & Laughlin 2001: 1143). All in all, its consumption rate is only topped by the energy intake of the heart (Dunbar & Shultz 2007: 1344).”

Here’s the link. The brain volume data and the 20-25 % weren’t new numbers to me but the others were.

July 28, 2010 Posted by | biology | Leave a comment

The picture of Dorian Gray

I had the book recommended to me by my little brother last year, but I never got around to reading it until now. I haven’t done as much book-reading (though I’ve done plenty of that other stuff) as I’d have liked for the last couple of weeks, but I’m glad I at least got started on this one – it’s a wonderful book!

A few quotes:

1) […] “beauty, real beauty, ends where an intellectual expression begins. Intellect is itself a mode of exaggeration, and destroys the harmony of any face. The moment one sits down to think, one becomes all nose, or all forehead, or something horrid. Look at the succesful men in any of the learned professions. How perfectly hideous they are! Except, of course, in the Church. But then in the Church they don’t think. A bishop keeps on saying at the age of eighty what he was told to say when he was a boy of eighteen, and as a natural consequence he always looks absolutely delightful.”

2) “You seem to forget that I am married, and the one charm of marriage is that it makes a life of deception absolutely necessary for both parties. I never know where my wife is, and my wife never knows what I am doing. When me meet – we do meet occasionally, when we dine out together, or go down to the Duke’s – we tell each other the most absurd stories with the most serious faces. My wife is very good at it – much better, in fact, than I am. She never gets confused over her dates, and I always do.”

3) “You know we poor artists have to show ourselves in society from time to time, just to remind the public that we are not savages. With an evening coat and a white tie, as you told me once, anybody, even a stockbroker, can gain a reputation for being civilised.”

4) “‘I make a great difference between people. I choose my friends for their good looks, my acquaintances for their good characters, and my enemies for their good intellects. A man cannot be too careful in the choice of his enemies. I have not got one who is a fool.’ […]
‘according to your category I must be merely an acquaintance.’
‘My dear old Basil, you are much more than an acquaintance.’
‘And much less than a friend. A sort of brother, I suppose?’
‘Oh, brothers! I don’t care for brothers. My elder brother won’t die, and my younger brothers seem never to do anything else.'”

5) “‘I quite sympathise with the rage of the English democracy against what they call the vices of the upper orders. The masses feel that drunkenness, stupidity, and immorality should be their own special property, and that if anyone of us makes an ass of himself he is poaching on their preserves.'”

All the quotes above are from the first ten pages of the book, this should tell you all you need to know. Btw, when writing this post, I found out that Wikiquote has a separate post on the book, so if you want to know a little more just follow this link.

July 25, 2010 Posted by | books | Leave a comment

Wikipedia (and other) articles of interest

1) Sun. How much do you really know about this thing? Do you know as much as you should?

2) Frog. More than 5,000 species are described, I had no idea there were that many. From the article:

“The skin of a frog is permeable to oxygen and carbon dioxide, as well as to water. There are a number of blood vessels near the surface of the skin. When a frog is underwater, oxygen is transmitted through the skin directly into the bloodstream. On land, adult frogs use their lungs to breathe. Their lungs are similar to those of humans, but the chest muscles are not involved in respiration, and there are no ribs or diaphragm to support breathing. Frogs breathe by taking air in through the nostrils (which often have valves which close when the frog is submerged), causing the throat to puff out, then compressing the floor of the mouth, which forces the air into the lungs.” […] “Frogs are known for their three-chambered heart, which they share with all tetrapods except birds, crocodilians and mammals. In the three-chambered heart, oxygenated blood from the lungs and de-oxygenated blood from the respiring tissues enter by separate atria, and are directed via a spiral valve to the appropriate vessel—aorta for oxygenated blood and pulmonary artery for deoxygenated blood. This special structure is essential to keeping the mixing of the two types of blood to a minimum, which enables frogs to have higher metabolic rates, and to be more active than otherwise.”

3) Qin Shi Huang. The first emperor of a unified China. Also it seems a really unpleasant human being.

4) Not from Wikipedia: The illusion of transparency. I’ve linked to youarenotsosmart before, I’ll likely do it again. The short version:

“The Misconception: When your emotions run high, people can look at you and tell what you are thinking and feeling.

The Truth: Your subjective experience is not observable, and you overestimate how much you telegraph your inner thoughts and emotions.”

5) History of the Hittites.

July 22, 2010 Posted by | astronomy, biology, history, Psychology, wikipedia | Leave a comment

En opfølgning

For et år siden deltog jeg i en øjenundersøgelse som jeg også omtalte her på bloggen. Jeg fik for ikke så længe siden et brev fra lægen som stod for studiet. I brevet stod bl.a.:

“Vi har analyseret data, og har fundet at øjendråberne påvirker blodgennemstrømningen i nethindens blodkar. Derfor kan de muligvis være en behandlingsmulighed for diabetisk øjensygdom i fremtiden.”

Det er godt nyt! I brevet fremgik det også, at et nyt studie er påbegyndt, som vil undersøge et tredje præparat. Jeg regner også med at deltage i dette studie og har udtrykt min interesse i at deltage.

Her er et let relateret link. Helt ærligt, hvor lavt kan man synke? Hvordan kan sådan et menneske se sig selv i spejlet? Skodkultur er om noget et pænt ord at bruge.

July 20, 2010 Posted by | diabetes, personligt | Leave a comment

Quote of the day (week? month?)

It’s been a slow couple of weeks so I decided it was probably a good idea to at least post something now, lest anyone should think I’d decided to give up the blog. Not for the faint of heart:

Philosopher Han Fei Tzu, a member of the ruling aristocracy of the 3rd century BC, who developed a school of law, wrote: “As to children, a father and mother when they produce a boy congratulate one another, but when they produce a girl they put it to death.”[54] Among the Hakka people, and in Yunnan, Anhwei, Szechwan, Jiangxi and Fukien a method of killing the baby was to put her into a bucket of cold water, which was called “baby water”.

More here.

July 17, 2010 Posted by | quotes | Leave a comment

Wikipedia articles of interest

I think I’ll drop the word random from the post titles of these posts in the future. It’s only the subjects that are somewhat random, not the articles – I go through a non-trivial amount of effort to pick out some of the most interesting of the articles I read. Anyway…

1) Orbital mechanics.

2) Pelagic fish.

…wait, reading an article about fish? Is that guy serious? How boring! …think again:

(more here. Also, here’s an article providing some more context).

3) Roman–Persian Wars. A featured article. There were a lot of wars going on but I doubt this region is all that special in that regard – the difference is that in this region of the world there were often someone around who’d write down something after people had stopped killing each other. If you’re somewhat unfamiliar with this argument, go here and extrapolate. Here’s btw. a nice illustration from the article, click to enlarge:

Case in point: The ‘West African Peoples’ didn’t write much, if anything, down. That’s why they’re called ‘West African Peoples’.

4) Brown rat. It’s a pretty successful species:

‘The only brown rat-free zones in the world are the Arctic, the Antarctic, some especially isolated islands, the province of Alberta in Canada,[45] and certain conservation areas in New Zealand[46][47]’

5) Lake Baikal. Never heard of it? You should have. It is ‘the most voluminous freshwater lake in the world with an average depth of 744.4 m (2,442 ft) and contains a total of roughly 20% of the world’s surface fresh water.’ It’s more than 25 million years old.

Here’s one image of (part of) the lake:

And here’s another:

6) Candela. The SI base unit of luminous intensity. Lots of related links in the article.

July 11, 2010 Posted by | biology, Geography, history, Physics, wikipedia | Leave a comment

Books I’d like to own but do not (yet)

My birthday is not all that far away, so I’ve made a wish list. A few books from the list – regular readers ought to recognize at least a couple of the titles:

Swann’s Way, Proust.

Samurai William, Giles Milton.

The Aeneid, Virgil.

Reflections; or Sentences and Moral Maxims, François de La Rochefoucauld.

– Any book from the Discworld series by Terry Pratchett. I have read a few of them but I don’t own any of them. I want them all on my bookshelf.

The Fall of the Roman Empire, Peter Heather.

Chess Opening Essentials, Vol. 3: Indian Defences, Komarov, Djuric & Pantaleoni.

The hound of the Baskervilles, Conan Doyle.

The Naked Sun, Isaac Asimov. Have read a Danish version of this book, would like to have/read it in English.

If you can’t think of anything else to read during the Summer, some of these books should be worth spending time with. Or so I’ve heard. If I had to pick only one, I’d go for Rochefoucauld.

July 7, 2010 Posted by | books | Leave a comment

There’s more to the Dunning-Kruger effect than you think

…or less, whichever way one might look at it.

After reading this post I was made aware of the fact that I had gotten it a bit wrong in my mind – primarily of course on account of being too lazy to actually read the damn study.

The D-K effect, or the consequenses of it, however you want to look at it, does not necessarily mean that marginally less competent people consider themselves more competent than marginally more competent people. From the original study:

People who are less competent are more likely to overestimate their own ability than more competent people are. There’s no doubt about that, and as the authors note in the paper, this is not just a result of erronous peer assessment, ie. that the overconfidence of the less skilled is caused (solely) by their faulty assumptions about other peoples’ skills, rather than by faulty assumptions about their own skills. The effect causes the (assumed) skill distribution to flatten – skilled people assume that they are more skilled than less skilled individuals and vice versa, but especially among low skilled individuals, the skill differential that exists between them and the more skilled individuals are assumed to be much smaller than it actually is – but it needn’t affect the absolute ordering of subjects. I had assumed that the D-K effect also necessarily resulted in a change in the ordering of individuals on some relevant margin, presumably somewhere in the higher end of the skill distribution, however this is not necessarily the case – d(Perceived ability)/d(Actual test score) is less than one but above zero everywhere in the specific study, the main results of which I posted above in the graph. In the second study they described in their paper, that is no longer the case, but whether the variable differences between actual test scores and perceived ability across individuals cause the ‘subjective ordering distribution’ to differ from the ‘objective ordering distribution’ is not clear cut.

Do note that the ‘no parent thinks his/her child is below average’-effect is probably closely related to the dynamics of the D-K framework. I have always thought that this was a very strange thing. However if nobody think that they are below average (look at the y-axis above), it makes a bit more sense. And a lot less sense, because that’s just plain weird!

Do also note that no matter who you are and what we’re measuring, one can always construct a skill distribution where you will be low skilled.

July 7, 2010 Posted by | Psychology, random stuff | 2 Comments

Quotes

1. Doubt, n. The philosophical device Descartes so cleverly used to prove everything he previously believed.

L. A. Rollins, Lucifer’s Lexicon

2. Man, n. An irrational animal whose irrationality is best demonstrated by his irrational belief in his rationality.

-ll-

3. I was gratified to be able to answer promptly, and I did. I said I didn’t know.

Mark Twain

4. Convictions are more dangerous enemies of truth than lies.

Nietzsche

5. A superstition is a premature explanation that overstays its time.

George Iles

6. A thing is not necessarily true because a man dies for it.

Oscar Wilde

7. All women become like their mothers. That is their tragedy. No man does. That’s his.

-ll-

8. Thirty-five is a very attractive age. London society is full of women of the very highest birth who have, of their own free choice, remained thirty-five for years.

-ll-

9. In this world there are only two tragedies. One is not getting what one wants, and the other is getting it.

-ll-

10. ‘We don’t want to hear negative things about ourselves. If someone says to you “you’re a very honest person, but it takes people a while to really get to know you” then you’re almost certainly going to agree, because it’s not negative in any way. Turn that around and say the opposite – “you’re deceptive and people can read you like an open book” is awful. No one wants to hear that, it makes him or her sound shallow and evil.’

Paul Michael (‘advertising guru‘)

The first five quotes I found here. As to Wilde: The Picture of Dorian Gray has been standing on my bookshelf unread for way too long, I expect to start reading it next week.

July 5, 2010 Posted by | books, quotes | Leave a comment

Random wikipedia links of interest

1. Orogeny.

‘Before the development of geologic concepts during the 19th century, the presence of mountains was explained in Christian contexts as a result of the Biblical Deluge. This was an extension of Neoplatonic thought, which influenced early Christian writers and assumed that a perfect Creation would have to have taken the form of a perfect sphere. Such thinking persisted into the 18th century.’

Of course this could just be the confirmation bias talking, but I think the ‘religion makes you more stupid and less knowledgeable’-hypothesis gets yet another point here.

2) Coalworker’s pneumoconiosis – ‘a common affliction of coal miners and others who work with coal, similar to both silicosis from inhaling silica dust, and to the long-term effects of tobacco smoking. Inhaled coal dust progressively builds up in the lungs and is unable to be removed by the body; that leads to inflammation, fibrosis, and in the worst case, necrosis.’

3) Hand grenade. Did you know that a gunpowder version of this weapon (Zhen Tian Lei – that article is only a stub, unfortunately) was developed more than 1000 years ago – I most certainly did not.

4) Gene expression. This is a dangerous article, it has a lot of good links and can cost you many hours of your life if you’re not careful. As I’m sure regular readers would know, the name of the article is of course also the name of one of my favourite blogs.

5) Simpson’s paradox.

6) Noisy-channel coding theorem.

‘the noisy-channel coding theorem establishes that however contaminated with noise interference a communication channel may be, it is possible to communicate digital data (information) nearly error-free up to a given maximum rate through the channel.’

[…]

‘Stated by Claude Shannon in 1948, the theorem describes the maximum possible efficiency of error-correcting methods versus levels of noise interference and data corruption. The theory doesn’t describe how to construct the error-correcting method, it only tells us how good the best possible method can be. Shannon’s theorem has wide-ranging applications in both communications and data storage. This theorem is of foundational importance to the modern field of information theory. Shannon only gave an outline of the proof. The first rigorous proof is due to Amiel Feinstein in 1954.

The Shannon theorem states that given a noisy channel with channel capacity C and information transmitted at a rate R, then if R < C there exist codes that allow the probability of error at the receiver to be made arbitrarily small. This means that, theoretically, it is possible to transmit information nearly without error at any rate below a limiting rate, C.’

I’d file this one under ‘stuff I didn’t know I didn’t know’. There’s a lot of that stuff around.

July 3, 2010 Posted by | Computer science, genetics, Geology, medicine, statistics, wikipedia | Leave a comment

Current projects

1) Reading Conan Doyle:

and have started reading John Stuart Mill:

The Conan Doyle book above is the first of three volumes of The Complete Sherlock Holmes published by Wordsworth Classics, which contains all Sherlock Holmes stories ever written by Doyle arranged chronologically in order of publication. So far I’ve read A study in Scarlet, The Sign of Four, A Scandal in Bohemia, The Red-Headed League, A Case of Identity, The Boscombe Valley Mystery, The Five Orange Pips and The Man With The Twisted Lip, which only amounts to 200 pages (the text size is very small and there’s a lot on each page, especially the first 120 pages which do not have any illustrations – the rest of the book do – the two first stories mentioned are actually novels, not short-stories). I read The Hound of the Baskervilles years ago (in Danish), but have otherwise never read anything by Doyle. After having read some of those short-stories, I’ve started thinking that stories like these when published were kind of the tv-series of that time, maybe I’m wrong. Anyway, I’d much rather be reading this stuff than be watching a randomly selected tv-show of today (keywords: randomly selected).

Haven’t read much of Mill yet, not enough to comment on it.

2)

As mentioned on the twitter, I’ve started playing this piece:

I’ve also started playing this:

I think Arrau plays it just a little too fast, but maybe that’s just me, and I didn’t want to spend a lot of time finding a ‘better’ version online.

Still working on this (but I haven’t gotten far, which was why I started playing the above stuff from the Chopin prelude):

July 3, 2010 Posted by | books, Chopin, music | Leave a comment

The myth of the Fat Burning Zone

“It is absolutely true that in a relative sense, the lower the exercise intensity the greater the reliance on fat as a substrate for energy. As the exercise intensity increases, the relative proportion of fat oxidation decreases while that of carbohydrate increases. However, the value of interest to anyone attempting to maximize fat loss is not what percentage of energy comes from fat during the exercise (relative), but how much fat is oxidized (absolute). This is where the fat burning zone breaks down.

While exercising at 60% of maximal heart rate (fat burning zone) the proportional use of fat is highest (63% – white numbers inside each red bar) while the absolute number of calories of fat burned is actually lower than that achieved at higher intensities (70, 75, and 80%) – much like comparing the Honda to the Mustang. In fact, although while exercising at 80% of maximal heart rate the relative use of fat is much lower (33% vs 63%) the absolute amount of fat burned is still greater (by approximately 10 calories).”

“Another reason the fat burning zone is inaccurate is because during more intense exercise TOTAL CALORIC expenditure is much higher.”

Link, via Razib Khan.

That last point is pretty important too. I burn maybe 1500 kcal everytime I run half a marathon, and currently I do that a couple of times a week on average. That’s a lot of calories. That’s one of the main reasons why long-distance runners are very rarely fat. I didn’t want to copy the whole post, but the last part of the post I linked to is pretty important too; if you want to lose weight, what you want to do is maximizing caloric expenditure given the time spent exercising – and walking is most often not the way to do that.

July 1, 2010 Posted by | data, random stuff | 3 Comments