i. “No really great man ever thought himself so.” (William Hazlitt)

ii. “We judge ourselves by what we feel capable of doing, while others judge us by what we have already done.” (Henry Wadsworth Longfellow)

iii. “I am more afraid of deserving criticism than of receiving it.” (-ll-)

iv. “The same principle leads us to neglect a man of merit that induces us to admire a fool.” (Jean de La Bruyère)

v. “The moderation of fortunate people comes from the calm which good fortune gives to their tempers.” (Rochefoucauld)

vi. “Investigate what is, and not what pleases.” (Goethe)

vii. “No one would talk much in society, if he knew how often he misunderstands others.” (-ll-)

viii. “Nothing is more damaging to a new truth than an old error.” (-ll-)

ix. “Very often when we have found ourselves forever separated from what we had intended to achieve, we have already, on our way, found something else worth desiring.” (-ll-)

x. “It is the most foolish of all errors for young people of good intelligence to imagine that they will forfeit their originality if they acknowledge truth already acknowledged by others.” (-ll-)

xi. “If some people hadn’t felt obliged to repeat what is untrue simply because they had at one point maintained it, they would have turned into quite different people.” (-ll-)

xii. “Only in quiet waters things mirror themselves undistorted. Only in a quiet mind is adequate perception of the world.” (Hans Margolius)

xiii. “Living well is the best revenge.” (George Herbert)

xvi. “[Education] has produced a vast population able to read but unable to distinguish what is worth reading.” (G. M. Trevelyan)

xv. “Many who burnt heretics in the ordinary way of their business were otherwise excellent people.” (G. M. Trevelyan, “Bias in History”)

xvi. “Does a man of sense run after every silly tale of hobgoblins or fairies, and canvass particularly the evidence? I never knew anyone, that examined and deliberated about nonsense who did not believe it before the end of his enquiries.” (David Hume)

xvii. “He is happy, whose circumstances suit his temper; but he is more excellent, who can suit his temper to any circumstances.” (-ll-)

xviii. “Hear the verbal protestations of all men: Nothing so certain as their religious tenets. Examine their lives: You will scarcely think that they repose the smallest confidence in them.” (-ll-)

xix. “Men have, in general, a much greater propensity to overvalue than undervalue themselves […] custom has established it as a rule, in common societies, that men should not indulge themselves in self-praise, or even speak much of themselves; and it is only among intimate friends […] that one is allowed to do himself justice. […] He must be a very superficial thinker, who imagines that all instances of mutual deference are to be understood in earnest, and that a man would be more esteemable for being ignorant of his own merits and accomplishments. A small bias towards modesty, even in the internal sentiment, is favourably regarded, especially in young people; and a strong bias is required in the outward behaviour; but this excludes not a noble pride and spirit, which may openly display itself in its full extent, when one lies under calumny or oppression of any kind.” (-ll-, An Enquiry Concerning the Principles of Morals)

xx. “I am convinced that, where men are the most sure and arrogant, they are commonly the most mistaken, and have there given reins to passion, without that proper deliberation and suspense, which can alone secure them from the grossest absurdities.” (-ll-)

June 29, 2013 Posted by | quotes | Leave a comment

Wikipedia articles of interest

i. Otto I, Holy Roman Emperor.

Otto I (23 November 912 – 7 May 973), also known as Otto the Great, was the founder of the Holy Roman Empire, reigning from 936 until his death in 973. The oldest son of Henry I the Fowler and Matilda of Ringelheim, Otto was “the first of the Germans to be called the emperor of Italy”.[1]

Otto inherited the Duchy of Saxony and the kingship of the Germans upon his father’s death in 936. He continued his father’s work to unify all German tribes into a single kingdom and greatly expanded the king’s powers at the expense of the aristocracy. Through strategic marriages and personal appointments, Otto installed members of his own family to the kingdom’s most important duchies. This reduced the various dukes, who had previously been co-equals with the king, into royal subjects under his authority. Otto transformed the Roman Catholic Church in Germany to strengthen the royal office and subjected its clergy to his personal control.

After putting down a brief civil war among the rebellious duchies, Otto defeated the Magyars in 955, thus ending the Hungarian invasions of Europe. The victory against the pagan Magyars earned Otto the reputation as a savior of Christendom and secured his hold over the kingdom. By 961, Otto had conquered the Kingdom of Italy and extended his realm’s borders to the north, east, and south. In control of much of central and southern Europe, the patronage of Otto and his immediate successors caused a limited cultural renaissance of the arts and architecture. Following the example of Charlemagne‘s coronation as “Emperor of the Romans” in 800, Otto was crowned Emperor in 962 by Pope John XII in Rome.

Otto’s later years were marked by conflicts with the Papacy and struggles to stabilize his rule over Italy. Reigning from Rome, Otto sought to improve relations with the Byzantine Empire, which opposed his claim to emperorship and his realm’s further expansion to the south. To resolve this conflict, the Byzantine princess Theophanu married his son, Otto II, in April 972. Otto finally returned to Germany in August 972 and died of natural causes in 973. Otto II succeeded him as Emperor.”

This part made me scratch my head: “Otto called the feuding parties to his court at Magdeburg, where Eberhard was ordered to pay a fine, and his lieutenants were sentenced to carry dead dogs in public, a particularly dishonoring punishment.” Carry dead dogs in public? Seriously? The article incidentally has many examples of how ‘the game of thrones’ was played by Otto and his comtemporaries (strategic marriages, hidden agreements, banquets held where the people who showed up got massacred, …). Here’s a little more stuff from the article:

“In the early summer of 951, before his father marched across the Alps, Otto’s son Liudolf, Duke of Swabia, invaded Lombardy in northern Italy. From his stronghold in Swabia located just north of the Alps, Liudolf was in closer proximity to the Italian border than his father in Saxony. While the exact reason for Liudolf’s actions are unclear, dynastic concerns and family ties to Adelaide may have been a factor. Adelaide’s mother, Bertha of Swabia, was a daughter of Regelinda, the mother of Liudolf’s wife Ida, from her first marriage to Burchard II, Duke of Swabia. Liudolf, therefore, may have intervened in the Italian campaign at the request of Adelaide’s relatives. Additionally, Liudolf, 19 years old himself, did not view the idea of a young step-mother as in his best interests. Though Otto had named him as his successor, Liudolf feared any potential step-brother may usurp his claim to the German throne.

The purpose of Liudolf’s Italian campaign was to overthrow Berengar II and therefore render unnecessary Otto’s own expedition into Italy, and thus his marriage to Adelaide. While Liudolf was preparing his expedition, the Bavarian Duke Henry, Otto’s brother and Liudolf’s uncle, conspired against him; Swabia and Bavaria shared a long common border and the two dukes were involved in a border dispute. Henry influenced the Italian aristocrats not to join Liudolf’s campaign. When Liudolf arrived in Lombardy, he found no support and was unable to sustain his troops. His army was near destruction until Otto’s own army crossed the Alps. […] With the humiliating failure of his Italian campaign and Otto’s marriage to Adelaide, Liudolf became estranged from his father and planned a rebellion. […]

Word of the rebellion reached Otto at Ingelheim. In order to secure his position, he traveled to his stronghold at Mainz. The city was also the seat of Archbishop Frederick of Mainz, who acted as the spokesman for the rebels and offered himself as a mediator between Otto and the rebels, who quickly arrived in Mainz. Recorded details of the meeting or the negotiated treaty do not exist, but Otto soon left Mainz with a peace treaty favorable to the conspirators, most likely confirming Liudolf as heir apparent and approving Conrad’s original agreement with Berengar II, making the treaty contrary to the desires of Adelaide and Henry.

When Otto returned to Saxony, Adelaide and Henry persuaded the king to void the treaty. Convening the Imperial Diet at Fritzlar, Otto declared Liudolf and Conrad as outlaws in absentia.[25] […] Otto’s actions at the Diet prompted the people of Swabia and Franconia into civil war against their king. […] The Hungarians invaded Otto’s domain as part of the larger Hungarian invasions of Europe and ravaged much of Southern Germany during Liudolf’s civil war. Though Otto had installed the Margraves Hermann Billung and Gero on his kingdom’s northern and northeastern borders, the Principality of Hungary to the southeast was a permanent threat to German security.”

These were ‘interesting times’…

ii. Enceladus (moon) (featured).

Enceladus is the sixth-largest of the moons of Saturn.[12] It was discovered in 1789 by William Herschel.[13]

Enceladus seems to have liquid water under its icy surface. Cryovolcanoes at the south pole shoot large jets of water ice particles into space. Some of this water falls back onto the moon as “snow”, some of it adds to Saturn’s rings, and some of it reaches Saturn. The whole of Saturn’s E ring is believed to have been made from these ice particles. Because of the apparent water at or near the surface, Enceladus may be one of the best places for humans to look for extraterrestrial life.”

600px-Enceladus_from_VoyagerIt’s not very big, here’s a to-scale size comparison made by NASA:


“In 2005 the Cassini spacecraft performed several close flybys of Enceladus, revealing the moon’s surface and environment in greater detail. In particular, the probe discovered a water-rich plume venting from the moon’s south polar region. This discovery, along with the presence of escaping internal heat and very few (if any) impact craters in the south polar region, shows that Enceladus is geologically active today. Moons in the extensive satellite systems of gas giants often become trapped in orbital resonances that lead to forced libration or orbital eccentricity; proximity to the planet can then lead to tidal heating of the satellite’s interior, offering a possible explanation for the activity.

Enceladus is one of only three outer Solar System bodies, with Jupiter‘s moon Io‘s sulfur volcanoes and Neptune‘s moon Triton‘s nitrogen “geysers” where active eruptions have been observed. Analysis of the outgassing suggests that it originates from a body of subsurface liquid water, which along with the unique chemistry found in the plume, has fueled speculations that Enceladus may be important in the study of astrobiology.[14] The discovery of the plume has added further weight to the argument that material released from Enceladus is the source of the E ring. […]

Because it reflects so much sunlight, the mean surface temperature at noon only reaches −198 °C (somewhat colder than other Saturnian satellites).[8] […]

Images taken by Cassini during the flyby on July 14, 2005 revealed a distinctive, tectonically deformed region surrounding Enceladus’s south pole. This area, reaching as far north as 60° south latitude, is covered in tectonic fractures and ridges.[2][40] The area has few sizable impact craters, suggesting that it is the youngest surface on Enceladus and on any of the mid-sized icy satellites; modeling of the cratering rate suggests that some regions of the south polar terrain (SPT) are possibly as young as 500,000 years, or younger.[2]

iii. Pax Mongolica (‘good article’).

“The Pax Mongolica (less often known as Pax Tatarica)[1] is a Latin phrase meaning “Mongol Peace” coined by Western scholars to describe the stabilizing effects of the conquests of the Mongol Empire on the social, cultural, and economic life of the inhabitants of the vast Eurasian territory that the Mongols conquered in the 13th and 14th centuries. The term is used to describe the eased communication and commerce the unified administration helped to create, and the period of relative peace that followed the Mongols’ vast conquests. The term was coined in parallel to Pax Romana.

The conquests of Kublai Khan and his successors effectively connected the Eastern world with the Western world, ruling a territory from Southeast Asia to Eastern Europe. The Silk Road, connecting trade centers across Asia and Europe, came under the sole rule of the Mongol Empire. It was commonly said that “a maiden bearing a nugget of gold on her head could wander safely throughout the realm.”[2][3] The end of the Pax Mongolica was marked by political fragmentation of the Mongol Empire and the outbreak of the Black Death in Asia which spread along trade routes to much of the world.”

iv. Marco Polo (‘good article’).

Marco Polo (Listeni/ˈmɑrk ˈpl/; Italian pronunciation: [ˈmarko ˈpɔːlo]; c.1254 – January 8–9, 1324)[1] was an Italian merchant traveler from the Republic of Venice[2][3] whose travels are recorded in Livres des merveilles du monde, a book which did much to introduce Europeans to Central Asia and China. He learned the mercantile trade from his father and uncle, Niccolò and Maffeo, who traveled through Asia, and apparently met Kublai Khan. In 1269, they returned to Venice to meet Marco for the first time. The three of them embarked on an epic journey to Asia, returning after 24 years to find Venice at war with Genoa; Marco was imprisoned, and dictated his stories to a cellmate. He was released in 1299, became a wealthy merchant, married and had three children. He died in 1324, and was buried in San Lorenzo.

His pioneering journey inspired Christopher Columbus[4] and many other travellers.”

Do note that the version of the Fra Mauro map included as an illustration to the article is ‘upside down’; in the original version of that map south was at the top and north at the bottom…

v. Royal Navy. All you ever wanted to know about the Royal Navy of Britain and its history. Well, not really, but that’s probably also a bit much to ask for; for example the article never even mentions the Singapore Strategy. I should point out that there are many featured articles in these areas of wikipedia even if this article is not one of them (the Singapore Strategy article however is); specific warships which saw action during the World Wars for example often have very detailed and well-written (i.e. featured-) articles (see e.g. German Battleship Bismarck, HMS Furious, HMS Eagle, HMS Royal Oak, … – here’s a list of WW2 ships…) and the coverage of ship-classses is often great too (see e.g. Dreadnought, Ironclad warship, Battleship, Yamato-class battleshipCourageous-class battlecruiser …).

vi. Mount Kenya (‘good article’).

vii. Meristem.

“A meristem is the tissue in most plants containing undifferentiated cells (meristematic cells), found in zones of the plant where growth can take place.

Meristematic cells give rise to various organs of the plant and keep the plant growing. The Shoot Apical Meristem (SAM) gives rise to organs like the leaves and flowers. The cells of the apical meristems – SAM and RAM (Root Apical Meristem) – divide rapidly and are considered to be indeterminate, in that they do not possess any defined end fate. In that sense, the meristematic cells are frequently compared to the stem cells in animals, which have an analogous behavior and function.

The term meristem was first used in 1858 by Karl Wilhelm von Nägeli (1817–1891) in his book Beiträge zur Wissenschaftlichen Botanik.[1] It is derived from the Greek word merizein (μερίζειν), meaning to divide, in recognition of its inherent function.

In general, differentiated plant cells cannot divide or produce cells of a different type. Therefore, cell division in the meristem is required to provide new cells for expansion and differentiation of tissues and initiation of new organs, providing the basic structure of the plant body.”

viii. Wieferich prime.

“In number theory, a Wieferich prime is a prime number p such that p2 divides 2p − 1 − 1,[4] therefore connecting these primes with Fermat’s little theorem, which states that every odd prime p divides 2p − 1 − 1. Wieferich primes were first described by Arthur Wieferich in 1909 in works pertaining to Fermat’s last theorem, at which time both of Fermat’s theorems were already well known to mathematicians.[5][6]

Since then, connections between Wieferich primes and various other topics in mathematics have been discovered, including other types of numbers and primes, such as Mersenne and Fermat numbers, specific types of pseudoprimes and some types of numbers generalized from the original definition of a Wieferich prime. Over time, those connections discovered have extended to cover more properties of certain prime numbers as well as more general subjects such as number fields and the abc conjecture.

Despite a number of extensive searches, the only known Wieferich primes to date are 1093 and 3511 (sequence A001220 in OEIS).”

It’s worth having these guys in mind when you’re thinking about limits – “It has been conjectured (as for Wilson primes) that infinitely many Wieferich primes exist” – but only two (2!) such numbers are currently known, and: “It is now known, that if any other Wieferich primes exist, they must be greater than 6.7×1015.” Sometimes it takes a lot of time to get to infinity… Incidentally only 48 Mersenne primes, a different type of primes, are known and it’s also hypothesized that there’s an infinite number of those…

June 29, 2013 Posted by | astronomy, biology, history, mathematics, wikipedia | Leave a comment


An awesome book!

A quote:

“Throughout the previous pages I have been assuming—what perhaps should have been laid down at the beginning as a distinct and fundamental proposition—that every human being in Flatland is a Regular Figure, that is to say of regular construction. By this I mean that a Woman must not only be a line, but a straight line; that an Artisan or Soldier must have two of his sides equal; that Tradesmen must have three sides equal; Lawyers (of which class I am a humble member), four sides equal, and, generally, that in every Polygon, all sides must be equal.

The size of the sides would of course depend upon the age of the individual. A Female at birth would be about an inch long, while a tall adult Woman migh extend to a foot. As to the Males of every class, it may be roughly said that the lenght of an adults’ sides, when added together, is two feet or a little more. But the size of our sides is not under consideration. I am speaking of the equality of sides, and it does not need much reflection to see that the whole of the social life in Flatland rests upon the fundamental fact that Nature wills all Figures to have their sides equal.

If our sides were unequal our angles might be unequal. Instead of its being sufficient to feel, or estimate by sight, a single angle in order to determine the form of an individual, it would be necessary to ascertain each angle by the experiment of Feeling. But life would be too short for such a tedious groping. The whole science and art of Sight Recognition would at once perish; Feeling, as far as it is an art, would not long survive; intercourse would become perilous or impossible; there would be an end to all confidence, all forethought; no one would be safe in making the most simple social arrangements; in a word, civilization would relapse into barbarism.”

He points out a little later in the story that: “If my Readers have followed me with any attention up to this point, they will not be surprised to hear that life is somewhat dull in Flatland.” But things used to be different – included in the story is the awesome tale of the Colour Revolt and its suppression – and the character we follow probably lives one of the most exciting lives of any Flatlander alive at that point; we are told about his adventures/experiences while visiting Lineland and Spaceland as well as his brief visit to the king of Pointland, among other things.

This is a short but wonderful book!

June 28, 2013 Posted by | books, mathematics | 3 Comments

Terence Tao on primes and other stuff

Two interesting videos I came across:

He’s talking to an audience who is presumed (..I assume, from his comments along the way..) not to know what a limit is or what the central limit theorem is about, so of course this is a very ‘unstructured’ review – he has to take a lot of shortcuts… As he points out at some point during the end when dealing briefly with his own work: “There’s absolutely no chance I can tell you about how this is proven” – but it’s still interesting stuff. As some of you will know I’ve covered many of the things covered in this video before here on the blog, and if you’re interested to know more about these things Brit Cruise’ applied math playlist on Khan Academy deals with similar stuff and has a more detailed overview of some of these things. This is probably also a good place to remind you of the existence of Simon Singh’s The Code Book.

The second video is more technical. If you watched the first one you should probably just skip the first ten minutes of this which is mostly just a recap:

A quote from the second lecture: “One funny thing about number theory, as opposed to other fields of mathematics, is that we can’t prove everything we want […] but we can conjecture things really well … so almost any question about the primes we can say very confidently whether it’s true or false, whether something is true about the primes, and we have lots of numerical evidence, lots of heuristic evidence, but we can’t prove most of that. Our ability to conjecture is about one hundred years ahead of our ability to prove things … we have all these conjectures, and we’re pretty much, like 99 percent certain they’re all true, it’s just that we can’t prove any of them.”

If you want to know what he and Ben Green did (and you happen to know a lot of stuff about math/number theory/…), you can have a go at their paper here). Here’s a screencap from the paper, illustrating what kind of stuff’s involved (click to view full size):

screencap Tao

June 27, 2013 Posted by | Lectures, mathematics | Leave a comment

A Storm of Swords (II)

I finished the book. It’s pretty awesome, I decided to give it 5 stars on goodreads. Lots of unexpected twists and plot developments – I will say no more than that in order not to ‘spoil’ anything, but I will add that nobody who reads this book will see everything coming that Martin throws at us in this book; this is simply not possible, and it’s a big part of what makes it great. You keep guessing, assuming, etc. – but you’ll often feel as much in the dark about what’s going to happen as do presumably the characters you’re reading about.

I did not spend as much time (book) reading during the last week as I did in the preceding weeks, and you don’t finish this book in an afternoon. Anyway now I’m done, and I can safely say that it’s well worth the time. Next up: A feast for crows.

June 25, 2013 Posted by | books | Leave a comment

Some times I don’t know why I even bother…

Here’s what a ‘lost’ position looks like:

Lost game
I was white – I lost on time in this position (i.e. it was my move – so that last rook of his, well…). This happens more often than I care to admit when I play blitz or bullet games. On the plus side, my tactics abilities have improved a lot over the last year. I’m currently #60 on the tactics trainer top 100 list on Playchess.

I haven’t blogged much the last few days, so I decided to post a few videos with game analyses below; the first one is from the Norway Chess 2013 Super Tournament, the last ones from the FIDE Thessaloniki Tournament. Incidentally Gelfand just won Tal Memorial, in case anybody cares.

June 24, 2013 Posted by | Chess | Leave a comment


i. “One of the greatest disservices you can do a man is to lend him money that he can’t pay back.” (Jesse Holman Jones)

ii. “I wish it were possible to obtain a single amendment to our constitution. I would be willing to depend on that alone for the reduction of the administration of our government to the genuine principles of it’s constitution; I mean an additional article, taking from the federal government the power of borrowing.” (Thomas Jefferson)

iii. “Not to know what happened before one was born is always to be a child.” (Cicero)

iv. “We know what we are, but know not what we may be.” (Shakespeare)

v. “A life of knowledge is not often a life of injury and crime.” (Sydney Smith)

vi. “every law which originated in ignorance and malice, and gratifies the passions from whence it sprang, we call the wisdom of our ancestors: when such laws are repealed, they will be cruelty and madness; till they are repealed, they are policy and caution.” (-ll-)

vii. “Have the courage to be ignorant of a great number of things, in order to avoid the calamity of being ignorant of everything.” (-ll-)

viii. “Among the smaller duties of life I hardly know any one more important than that of not praising where praise is not due.” (-ll-)

ix. “It is the greatest of all mistakes to do nothing because you can only do little.” (-ll-)

x. “No furniture so charming as books.” (-ll-)

xi. “The good life is one inspired by love and guided by knowledge.” (Bertrand Russell)

xii. “We have all forgot more than we remember.” (Thomas Fuller)

xiii. “He knows little who will tell his wife all he knows.” (-ll-)

xiv. “Misfortunes cannot suffice to make a fool into an intelligent man.” (Cesare Pavese)

xv. “There is nothing so wretched or foolish as to anticipate misfortunes. What madness it is in your expecting evil before it arrives!” (Nil est nec miserius nec stultius quam prætimere. Quæ ista dementia est, malum suum antecedere – Seneca the Younger)

xvi. “philosophy teaches us to act, not to speak; it exacts of every man that he should live according to his own standards, that his life should not be out of harmony with his words, and that, further, his inner life should be of one hue and not out of harmony with all his activities. This, I say, is the highest duty and the highest proof of wisdom, – that deed and word should be in accord, that a man should be equal to himself under all conditions, and always the same.” (-ll-, Moral Letters to Lucilius)

xvii. “A quiet life does not of itself give lessons in upright conduct; the countryside does not of itself teach plain living; no, but when witnesses and onlookers are removed, faults which ripen in publicity and display sink into the background.” (-ll-, letter 94)

xviii. “How many people live on the reputation of the reputation they might have made!” (Oliver Wendell Holmes)

xix. “It is fundamentally the confusion between effectiveness and efficiency that stands between doing the right things and doing things right. There is surely nothing quite so useless as doing with great efficiency what should not be done at all.” (Peter Drucker)

xx. “Shame is an ornament to the young; a disgrace to the old.” (Aristotle)

June 20, 2013 Posted by | quotes | Leave a comment

The pace of modern life

I had to share this one – it’s pretty awesome (click to view):


Link. In related(?) news, abstrusegoose has started updating again.


June 20, 2013 Posted by | comics, xkcd | Leave a comment

A storm of swords

I read 400 pages today. It’s quite good (4.51 average rating on goodreads), like the prequels. It’s also quite long, 1177 pages. As I pointed out before, the page count should not scare you off – it’s easy to read and there are lots of chapters so it’s easy to split it up into chunks. However there are chunks and then there are chunks; given the number of characters and the number of different storylines, I’d assume it’s probably easier to read it in one go than it is to read it over a long period of time. It’s much easier to remember who character X is if you first encountered him 6 hours ago than if you read about him two weeks ago, and there are a lot of Xs here. Also, if you were to read a book like this in segments of, say, one chapter (10-20 pages) per day, it would literally take you months to finish (78 days with a 15 pages/day reading scheme) and I consider it likely that it would be a very different experience from the one you’d have if you were to read it over a short period of time (a few days). These remarks naturally also apply to the prequels.

Incidentally, according to a very brief blog overview I just did this one will be the 25th book I read this year. I’ve sort of told myself that it would be nice to cross 50 books (52?) this year – that should still be quite feasible, even though the current rate (6 books during the last fortnight, and as mentioned 400 pages/day right now) is not exactly a long-term equilibrium.

I’m probably reading too much fiction these days. Oh well, my reading speed is not very impressive and I tell myself that reading fiction at least helps with that…

June 19, 2013 Posted by | books | 8 Comments

European Societies in the Bronze Age (II)

I finished the book. I ended up giving it 3 stars on goodreads, but as I read the last half I mostly moved closer to a 2-star evaluation. Part of the book is great, part of it is very weak. It’s best when it just deals with the facts; what do we find when we look in the different kinds of tombs left behind (and why might we not always find what we’d expect to find?), how big were the dwellings they lived in and what were they made of, how did these guys procure the metals we’ve been talking about, what did they eat, what did they wear and how did they make their clothes – questions like that. It’s much weaker when he’s engaging in various forms of bigger-picture theorizing, or telling me about the theories other people have come up with for this and that; many of those theories are presumably discussed and forwarded by people I’d prefer got fired from the institutions they work at.

Overall there’s much good stuff and I learned a lot – and as I did point out through the goodreads rating, overall I liked the book. Here’s one of the parts from the last half of the book which answered one of the many questions I’d been curious about the answer to before starting out:

“As with most prehistoric populations, people in the Bronze Age did not live long. Disease, whether chronic such as arthritis, or epidemic, such as viral infections, must have been prevalent at all times and places. Mortality studies invariably show a pattern whereby perinatal and infant mortality was extremely high and child mortality high; for those who survived into their teens, the chances of making it into adulthood were quite good, but by the age of 35 the odds against further survival increased dramatically. People older than 45 were unusual. This can be demonstrated from the analysis of El Argar, where a large sample (563 individuals) was studied: life expectancy at birth was 19.9 years, but at age 20 it was still a further 15.9 years;[19] the figures for Grossbrembach and Velika Gruda are not dissimilar.[20] Brothwell estimated an average lifespan for British Bronze Age males of 31.3 years and for females of 29.9 years, with only 3.3% surviving beyond 50.[21] […] Given the incidence of disease, the quality of life must in many cases have been poor. Those with chronic arthritis would have been in constant pain, and dependent on other members of the community for the maintenance of daily life. Even so ‘minor’ an affliction as tooth caries could have caused ongoing pain, while a tooth abscess could even have been life-threatening. Fourteen of the Grossbrembach adults had tooth caries, in some cases extensive.”

Wikipedia does not at present have enough material on the stuff covered in this book for you to be able to learn anywhere near the same amount of stuff about this topic as you would learn from reading this book (and I’m sure reading the book would make retention much easier than reading random wikipedia articles) – for instance see the main article on Bronze Age Europe, there’s not much stuff here. However below a few more links to stuff (‘samples of the kind of stuff’) covered in the book:

Apennine culture.
Wessex culture.
Hill fort.
Lusatian culture.

June 18, 2013 Posted by | anthropology, archaeology, books | Leave a comment

European Societies in the Bronze Age

“The production of charcoal is an aspect of metalworking that is often ignored.62 Charcoal was the ideal fuel for furnaces prior to the advent of coke because it promotes a strongly reducing atmosphere in the furnace, consisting as it does of almost pure carbon, and on burning creates an oxygen-starved atmosphere, essential if oxygen compounds are to be removed from the metal being worked. The forcing of air into an enclosed charcoal-burning furnace raises the temperature rapidly; charcoal has a calorific value about twice that of dried wood. To make charcoal, cut timber is ignited in a sealed heap or pit and allowed to smoulder; only sufficient oxygen is admitted at the start to get the fire going, after which the process continues without the addition of oxygen. By this means combustion is incomplete, no ash results, and almost everything except carbon is removed from the wood. Considerable quantities of timber would have been needed in the most prolific metal-production areas. It has been estimated that to produce 5 kg of copper metal one would need at least 100 kg of charcoal, which would in turn have required some 700 kg of timber, a considerable requirement in terms of labour.”

From European Societies in the Bronze Age (Cambridge World Archaeology), by A. F. Harding. I’ve roughly read the first half of this book today, and so far I like it – if it continues along the same lines, I’ll probably give it three stars on goodreads (where the average rating is currently 3.8). It’s easy to read and it has a lot of interesting stuff about things I do not know much about. Below I’ve added some wikipedia links to stuff related to what’s covered in the first six chapters – they should tell you a bit about what kind of stuff’s covered in this book.

Urnfield culture.
Clearance cairn.
The Thera eruption.
Wattle and daub.
Ard (plough).
Placer mining.

June 17, 2013 Posted by | anthropology, archaeology, books | Leave a comment

A Clash of Kings

I finished the book today. I’ve given it 4 stars on goodreads, where the average rating is 4.37.

The book was significantly easier for me to read than was the first one, in part because a lot of the main characters had already been introduced. There are plenty of new people joining the party in this book, but by now you have a basic framework to fit these people into which helps a lot.

I gather that there are characters for whom we’re supposed to feel sympathy featuring in this story, but they are few and sometimes it’s hard to like even the people whom you sort of assume you’re supposed to like. The types of people you’ll encounter in this narrative include mere children (many of the main characters are very young), and often children given way too much power way too early; dirtbags; fools; cowards; selfish jackasses; hateful ignoramuses; stubborn jerks; immature morons; greedy schemers, deceitful backstabbers; merciless murderers; and/or a combination of all of these things – an observation which I should point out, incidentally, is not meant as a criticism. This is rather part of what makes this book great, as is the fact that we’ll often learn people’s traits through their actions rather than through descriptions. People in these books to a significant extent behave the way you’d expect actual people to behave if they were to find themselves in the situations/settings/etc. the characters find themselves in – and we learn enough about the people and the social milieu to often understand quite well why they behave the way they do. But understanding why a person does something does not equate condoning said behaviour, which is part of why it may be hard to muster sympathy for a specific character and his/her actions. It should be noted that there are few ‘complete monsters‘ here; The Mountain and Sandor Clegane may be used as examples, as well as Joffrey – but at least the two of them we know most about (Sandor and Joffrey) are described in enough detail for us to understand at least something about how they’ve ended up the way they have, and why they behave the way they do. They are horrible people, and I’d be surprised to meet a person who’s read the first two books and didn’t have some non-trivial desire to see the Joffrey character dead (the Joffrey character is probably the most well-done hate sink I’ve ever encountered), but they are not ( me) unrealistically horrible people given the setting and what we know. They are rather human, all too human. A great thing about the story is that whereas the huge number of characters involved makes it near-impossible to know why all these people behave the way they do, we do get close enough to some of them to understand what’s going on and we’re constantly reminded that they all have their reasons for behaving the way they do, even if we don’t always know those reasons. And given that Westeros is a pretty crappy place at this point (though I have no doubt it’ll likely get worse), it should not surprise us that most of the people involved in this narrative don’t exactly behave like angels – I’ve touched upon related themes before.

I feel the need to point out that the prose in this work is nothing extraordinary; sometimes the language felt excessively ‘rough’ and ‘raw’ and in need of ‘polishing’. Then again perhaps that’s just me, I’ve sort of taken a liking to works where the author deliberately plays around a bit with the language, like e.g. Pratchett is wont to do in his works – but it is part of why I only gave it 4 stars, rather than 5. I guess the semi-neutral position here would be to simply remark that you shouldn’t read this book for the quotes – the language isn’t what’s driving this story, nor should it be; and it does work well enough to tell the tale.

I’m toying with the idea of reading the rest of the published series this summer as well. We’ll see. The books are quite long, but they don’t actually take all that long to read and the page count should not scare you away; as I’ve noted before I consider myself to be a rather slow (well, another word to use is ‘careful’, but…) reader, yet I can read one of these guys during a long weekend (2-3 days) without problems. Then again I don’t have much of a social life – if you do and you can’t just take a few days out of your life to read books like these, it’ll probably take you a bit longer than that. On the third hand the best time of year for most people to read books like these is probably now, or soon. As noted in the comments earlier it’s certainly possible to ‘save time’ by just watching the tv series instead and skip the books, but what I can tell you at this point is that the books are worth reading on their own.

June 16, 2013 Posted by | books | Leave a comment

Wikipedia articles of interest

i. Introduction to general relativity.


For anybody who does not know, there’s a simple version of wikipedia available, which tries to keep things as simple as possible so as many people as possible can understand what’s going on in those articles. The article I link to here is not from the simple wikipedia, but it is an in some sense ‘corresponding’ attempt by the wikipedia community to make general relativity more accessible to ‘the masses’. It’s a featured article, and there are lots of links. I read the main article on the subject matter (also featured) first, which is probably the wrong reading order if you plan on reading both.

ii. Transcendental number.

“In mathematics, a transcendental number is a (possibly complex) number that is not algebraic—that is, it is not a root of a non-zero polynomial equation with rational coefficients. The most prominent examples of transcendental numbers are π and e. Though only a few classes of transcendental numbers are known (in part because it can be extremely difficult to show that a given number is transcendental), transcendental numbers are not rare. Indeed, almost all real and complex numbers are transcendental, since the algebraic numbers are countable while the sets of real and complex numbers are both uncountable. All real transcendental numbers are irrational, since all rational numbers are algebraic. The converse is not true: not all irrational numbers are transcendental; e.g., the square root of 2 is irrational but not a transcendental number, since it is a solution of the polynomial equation x2 − 2 = 0. […]

The set of transcendental numbers is uncountably infinite. […] Any non-constant algebraic function of a single variable yields a transcendental value when applied to a transcendental argument. […] The non-computable numbers are a strict subset of the transcendental numbers.

All Liouville numbers are transcendental, but not vice versa.”

The article has more. Here’s a (very technical!) related article about the Lindemann-Weierstrass theorem.

iii. Diamond (featured).


“In mineralogy, diamond (from the ancient Greek αδάμας – adámas “unbreakable”) is a metastable allotrope of carbon, where the carbon atoms are arranged in a variation of the face-centered cubic crystal structure called a diamond lattice. Diamond is less stable than graphite, but the conversion rate from diamond to graphite is negligible at ambient conditions. Diamond is renowned as a material with superlative physical qualities, most of which originate from the strong covalent bonding between its atoms. In particular, diamond has the highest hardness and thermal conductivity of any bulk material. Those properties determine the major industrial application of diamond in cutting and polishing tools and the scientific applications in diamond knives and diamond anvil cells.

Diamond has remarkable optical characteristics. Because of its extremely rigid lattice, it can be contaminated by very few types of impurities, such as boron and nitrogen. Combined with wide transparency, this results in the clear, colorless appearance of most natural diamonds. Small amounts of defects or impurities (about one per million of lattice atoms) color diamond blue (boron), yellow (nitrogen), brown (lattice defects), green (radiation exposure), purple, pink, orange or red. Diamond also has relatively high optical dispersion (ability to disperse light of different colors), which results in its characteristic luster. Excellent optical and mechanical properties, notably unparalleled hardness and durability, make diamond the most popular gemstone.

Most natural diamonds are formed at high temperature and pressure at depths of 140 to 190 kilometers (87 to 120 mi) in the Earth’s mantle. Carbon-containing minerals provide the carbon source, and the growth occurs over periods from 1 billion to 3.3 billion years (25% to 75% of the age of the Earth). Diamonds are brought close to the Earth′s surface through deep volcanic eruptions by a magma, which cools into igneous rocks known as kimberlites and lamproites. Diamonds can also be produced synthetically in a high-pressure high-temperature process which approximately simulates the conditions in the Earth mantle. […] The rate at which temperature changes with increasing depth into the Earth varies greatly in different parts of the Earth. In particular, under oceanic plates the temperature rises more quickly with depth, beyond the range required for diamond formation at the depth required. The correct combination of temperature and pressure is only found in the thick, ancient, and stable parts of continental plates where regions of lithosphere known as cratons exist. Long residence in the cratonic lithosphere allows diamond crystals to grow larger.[11] […]

Diamond-bearing rock is carried from the mantle to the Earth’s surface by deep-origin volcanic eruptions. The magma for such a volcano must originate at a depth where diamonds can be formed[11] […] (three times or more the depth of source magma for most volcanoes). This is a relatively rare occurrence. These typically small surface volcanic craters extend downward in formations known as volcanic pipes.[11] […] The magma in volcanic pipes is usually one of two characteristic types, which cool into igneous rock known as either kimberlite or lamproite.[11] The magma itself does not contain diamond; instead, it acts as an elevator that carries deep-formed rocks (xenoliths), minerals (xenocrysts), and fluids upward. […]

Diamond is the hardest known natural material on the Mohs scale of mineral hardness, where hardness is defined as resistance to scratching and is graded between 1 (softest) and 10 (hardest). Diamond has a hardness of 10 (hardest) on this scale.[25] Diamond’s hardness has been known since antiquity, and is the source of its name.

Diamond hardness depends on its purity, crystalline perfection and orientation: hardness is higher for flawless, pure crystals oriented to the <111> direction (along the longest diagonal of the cubic diamond lattice). [….] Somewhat related to hardness is another mechanical property toughness, which is a material’s ability to resist breakage from forceful impact. The toughness of natural diamond has been measured as 7.5–10 MPa·m1/2.[27][28] This value is good compared to other gemstones, but poor compared to most engineering materials. […]

The production and distribution of diamonds is largely consolidated in the hands of a few key players, and concentrated in traditional diamond trading centers, the most important being Antwerp, where 80% of all rough diamonds, 50% of all cut diamonds and more than 50% of all rough, cut and industrial diamonds combined are handled.[46] This makes Antwerp a de facto “world diamond capital”.[47] Another important diamond center is New York City, where almost 80% of the world’s diamonds are sold, including auction sales.[46] […]

De Beers and its subsidiaries own mines that produce some 40% of annual world diamond production. For most of the 20th century over 80% of the world’s rough diamonds passed through De Beers,[48] but in the period 2001–2009 the figure has decreased to around 45%.[49] De Beers sold off the vast majority of its diamond stockpile in the late 1990s – early 2000s[50] and the remainder largely represents working stock (diamonds that are being sorted before sale).[51]  […]

80% of mined diamonds (equal to about 135,000,000 carats (27,000 kg) annually), unsuitable for use as gemstones, are destined for industrial use. In addition to mined diamonds, synthetic diamonds found industrial applications almost immediately after their invention in the 1950s; another 570,000,000 carats (110,000 kg) of synthetic diamond is produced annually for industrial use. Approximately 90% of diamond grinding grit is currently of synthetic origin.[74] […] Roughly 49% of diamonds originate from Central and Southern Africa, although significant sources of the mineral have been discovered in Canada, India, Russia, Brazil, and Australia.[74]

iv. Gropecunt Lane (featured – NSFW?).

Gropecunt Lane /ˈɡrpkʌnt ˈln/ was a street name found in English towns and cities during the Middle Ages, believed to be a reference to the prostitution centred on those areas; it was normal practice for a medieval street name to reflect the street’s function or the economic activity taking place within it. Gropecunt, the earliest known use of which is in about 1230, appears to have been derived as a compound of the words grope and cunt. Streets with that name were often in the busiest parts of medieval towns and cities, and at least one appears to have been an important thoroughfare. […]

Although some medieval street names such as Addle Street (stinking urine, or other liquid filth; mire[15]) and Fetter Lane (once Fewterer, meaning “idle and disorderly person”) have survived, others have been changed in deference to contemporary attitudes. Sherborne Lane in London was in 1272–73 known as Shitteborwelane, later Shite-burn lane and Shite-buruelane (possibly due to nearby cesspits).[16][17] Pissing Alley, one of several identically named streets whose names survived the Great Fire of London,[18] was called Little Friday Street in 1848, before being absorbed into Cannon Street in 1853–54.[19] Petticoat Lane, the meaning of which is sometimes misinterpreted as related to prostitution, was in 1830 renamed as Middlesex Street, following complaints about the street being named after an item of underwear.[20] […] As the most ubiquitous and explicit example of such street names, with the exception of Shrewsbury and possibly Newcastle (where a Grapecuntlane was mentioned in 1588) the use of Gropecunt seems to have fallen out of favour by the 14th century.[22] Its steady disappearance from the English vernacular may have been the result of a gradual cleaning-up of the name; Gropecuntelane in 13th-century Wells became Grope Lane, and then in the 19th century, Grove Lane.[23]

v. Mary Toft (featured).

Mary Toft (née Denyer; c. 1701–1763), also spelled Tofts, was an English woman from Godalming, Surrey, who in 1726 became the subject of considerable controversy when she tricked doctors into believing that she had given birth to rabbits.”

If that introduction doesn’t make you want to read this article, we probably can’t be friends… Here’s the rest of the introduction:

“In 1726 Toft became pregnant, but following her reported fascination with the sighting of a rabbit, she miscarried. Her claim to have given birth to various animal parts prompted the arrival of John Howard, a local surgeon, who investigated the matter. He delivered several pieces of animal flesh and duly notified other prominent physicians, which brought the case to the attention of Nathaniel St. André, surgeon to the Royal Household of King George I. St. André concluded that Toft’s case was genuine but the king also sent surgeon Cyriacus Ahlers, who remained sceptical. By then quite famous, Toft was brought to London and studied at length, where under intense scrutiny and producing no more rabbits she confessed to the hoax, and was subsequently imprisoned as a fraud.

The resultant public mockery created panic within the medical profession and ruined the careers of several prominent surgeons. The affair was satirised on many occasions, not least by the pictorial satirist and social critic William Hogarth, who was notably critical of the medical profession’s gullibility. Toft was eventually released without charge and returned home.”

The story is completely absurd, but also quite funny. I laughed out loud when I read this part, “The timing of Toft’s confession [7 December] proved awkward for St. André, who on 3 December had published his forty-page pamphlet A Short Narrative of an Extraordinary Delivery of Rabbets.[44]” Naturally this article is yet another gem from the wikipedia list of unusual articles.

vi. Small shelly fauna (‘good article’).

“The small shelly fauna or small shelly fossils, abbreviated to SSF, are mineralized fossils, many only a few millimetres long, with a nearly continuous record from the latest stages of the Ediacaran to the end of the Early Cambrian period. They are very diverse, and there is no formal definition of “small shelly fauna” or “small shelly fossils”. Almost all are from earlier rocks than more familiar fossils such as trilobites. Since most SSFs were preserved by being covered quickly with phosphate and this method of preservation is mainly limited to the Late Ediacaran and Early Cambrian periods, the animals that made them may actually have arisen earlier and persisted after this time span.

Some of the fossils represent the entire skeletons of small organisms, including the mysterious Cloudina and some snail-like molluscs. However, the bulk of the fossils are fragments or disarticulated remains of larger organisms, including sponges, molluscs, slug-like halkieriids, brachiopods, echinoderms, and onychophoran-like organisms that may have been close to the ancestors of arthropods.

One of the early explanations for the appearance of the SSFs – and therefore the evolution of mineralized skeletons – suggested a sudden increase in the ocean’s concentration of calcium. However, many SSFs are constructed of other minerals, such as silica. Because the first SSFs appear around the same time as organisms first started burrowing to avoid predation, it is more likely that they represent early steps in an evolutionary arms race between predators and increasingly well-defended prey. On the other hand mineralized skeletons may have evolved simply because they are stronger and cheaper to produce than all-organic skeletons like those of insects. Nevertheless it is still true that the animals used minerals that were most easily accessible.

Although the small size and often fragmentary nature of SSFs makes it difficult to identify and classify them, they provide very important evidence for how the main groups of marine invertebrates evolved, and particularly for the pace and pattern of evolution in the Cambrian explosion. Besides including the earliest known representatives of some modern phyla, they have the great advantage of presenting a nearly continuous record of Early Cambrian organisms whose bodies include hard parts. […]

Small shelly fossils are typically, although not always, preserved in phosphate. Whilst some shellies were originally phosphatic, in most cases the phosphate represents a replacement of the original calcite.[15] They are usually extracted from limestone by placing the limestone in a weak acid, typically acetic acid; the phosphatized fossils remain after the rock is dissolved away.[16] Preservation of microfossils by phosphate seems to have become less common after the early Cambrian, perhaps as a result of increased disturbance of sea-floors by burrowing animals.[15] Without this fossil-forming mode, many small shelly fossils may not have been preserved – or been impossible to extract from the rock; hence the animals that produced these fossils may have lived beyond the Early Cambrian – the apparent extinction of most SSFs by the end of the Cambrian may be an illusion.[16][3][4] For decades it was thought that halkieriids, whose “armor plates” are a common type of SSF, perished in the end-Botomian mass extinction; but in 2004 halkieriid armor plates were reported from Mid Cambrian rocks in Australia, a good 10 million years more recent than that.[17] […]

Biomineralization is the production of mineralized parts by organisms. Hypotheses to explain the evolution of biomineralization include physiological adaptation to changing chemistry of the oceans, defense against predators and the opportunity to grow larger. The functions of biomineralization in SSFs vary: some SSFs are not yet understood; some are components of armor; and some are skeletons. A skeleton is any fairly rigid structure of an animal, irrespective of whether it has joints and irrespective of whether it is biomineralized. Although some SSFs may not be skeletons, SSFs are biomineralized by definition, being shelly. Skeletons provide a wide range of possible advantages, including : protection, support, attachment to a surface, a platform or set of levers for muscles to act on, traction when moving on a surface, food handling, provision of filtration chambers and storage of essential substances.[2]

Incidentally I’ve now read the first half of George Martin’s A Clash of Kings – I’ll probably blog it tomorrow.

June 15, 2013 Posted by | Geology, history, mathematics, Paleontology, Physics, wikipedia | 2 Comments

Some data

I spent a bit of time on Statistikbanken, a site run by Statistics Denmark which gives you access to a lot of neat Danish data. Below a table I made from (SKI5), one of the databases; click to view full size:

Divorce 1

The variable to the left is a marriage duration indicator at the time of measurement – note that the years at the top (1980, 1990,…) are not the years where the marriages were formed, but rather the years of measurement – and they’re looking back in time and implicitly include marriages which were dissolved decades ago. So if you take the year 1980 for example, back then 21 % of marriages which had been going on (/…would have been going on…) for 10 years had been dissolved through divorce, whereas 36 % of marriages which had been going on for 30 years had ended in divorce. When I last looked at this stuff, I didn’t include these particular numbers and I got curious (plus I was bored).

Here’s what happens if you zoom in on the first 10 years of marriage:

Divorce 2

The bolded ones are the cohorts with the highest divorce rate for that specific marriage duration. Interestingly, although the 2012 numbers are generally a bit smaller than the rest the 1990 numbers are in most cases marginally higher than the 1980 numbers; some constant, ‘rule-based’ (monotonous?) development in divorce risk over time is hard to identify when you demand it be consistent with the information provided in the two tables above. That said, the numbers are actually in my opinion very similar all things considered – I’d assume that if you could compare these cohorts with earlier cohorts, you’d see more dramatic differences.

Okay, what about cars, busses and so on? How many of those are there in Denmark? This is the kind of question children ask, but when you become an adult most people stop asking these questions. I (childishly..) had a look, here are the numbers for the entire country (Statistikbanken, BIL707):


Despite population growth there’s been a decrease in the number of Danish busses, vans, and lorries during the last six years – the number of lorries has dropped 15%, and the number of vans dropped by roughly 10 %.

Here are the numbers for Region Hovedstaden, the area around Copenhagen. With 1.7 million people, this area makes up almost a third of the Danish population:


Whereas the population share of the region is around ~30%, the 2013 share of car-owners is ~27% – quite close to the national average. This really surprised me; I’d have assumed the number of car-owners was smaller than this, and that people relied more on public transportation; but the proportion of all Danish busses committed to this region is actually around ~30% (28,7), close to the population share of the region. I’d have expected the numbers to look different; that a biggish proportion of all Danish busses were committed to this region and that the number of car-owners was lower.

Incidentally there’s roughly one bus per 400 people in Denmark.

How many people are actually caught violating the national gun laws (‘weapons laws’ – the laws also regulate the use of other weapons such as knives and explosives; e.g. in Denmark it’s illegal to carry a knife with a blade longer than 7 centimeters on you, and until last year a violation of that law would lead to a mandatory one week prison sentence in the absence of exceptional extenuating circumstances)? I didn’t know and so I got curious. I looked at the data included in STRAF11, and it turns out that there were 6808 violations of the weapons law in Denmark in 2007 (before the knife law mentioned above was introduced in 2008), and 6517 in 2012. This is close to 18 people per day over the course of the year.

Computer and internet? How many families own a computer and/or have internet access at home? Unfortunately there are some missing data problems here, but here’s what they got (VARFORBR):

Computer and internet
As you’d expect internet lags computers a bit but there seems to have been convergence over time, and by now only a small minority do not have a computer at home. The above data is not, however, all the stuff they have when it comes to internet usage. I looked around and I found the DIS129 dataset, which deals with active internet subscriptions in Denmark. A funny thing is that if you compare the numbers you get from the two datasets, the numbers don’t really add up; internet penetrance is significantly lower if you base your conclusions on the register data from DIS129 than if you use VARFORBR, which is survey based (actually it’s clear from the description that the DIS129 dataset is also partly survey based, but it’s also made clear that the specific data I use here (there’s a lot of data in that dataset) are from the register-based part of the dataset).

I combined the DIS129 data – limiting myself to private (non-corporate) subscriptions and corporate internet subscriptions used by private individuals as well (i.e. ‘purely corporate’ internet subscriptions were excluded from the sample) – with the household data from FAM55N (we don’t care about internet subscriptions as such, we care about penetrance/adoption rates) to construct a variable indicating the proportion of households with active internet subscriptions. The DIS129 data has a data point for each six months; I decided I didn’t like that very much and so I averaged the data out in order to report only one data-point for each year – results are given below, first the ‘raw’ (averaged) subscription numbers, then the household data, and lastly the proportion of households with active internet subscriptions:

Active internet users


Internet subscribers
Maybe I should have included the word ‘estimated’ in front of ‘proportion’ in the title above, but all we have are estimates anyway, so…  Do note that the x-axes are not identical for the figures based on the VARFORBR and the DIS129 data – unsurprisingly the growth rate was much higher in the 90es than it has been later on; what you want to compare is the last graph above and the part of the VARFORBR graph for which the two x-axes match each other. It’s obvious that the VARFORBR numbers are significantly higher than the DIS129 numbers. In case you were wondering why I don’t compare similar time periods; I figured the development in the 90es was interesting (most adoption took place in the 90es), however the register data didn’t go back further than 2003. If it had I’d have included the data, but I didn’t think it made a lot of sense to exclude the data from the 90es from the VARFORBR data set just because corresponding figures didn’t exist in the DIS129 data set.

Purely corporate subscriptions make up roughly 10 percent of the market share, so not excluding those when calculating adoption rates may lead to a significant overestimate of household internet use. I believe I’ve seen higher adoption rates than the ones derived from the DIS129 data set reported in the media before, but I also believe these estimates have all been based on surveys by Statistics Denmark – so presumably they’re derived from the VARFORBR data set or the source material of this data set. Note that if you’re basing your estimate on the DIS129 sample then you could probably argue that the numbers provided are overestimates of the actual penetrance rates; some households may have more than one active internet subscription, and this arrangement is presumably more common than is the one where different households share the same internet connection. On the other hand they note in the documentation that the registers, despite being very comprehensive, may not be complete and that some relevant data here may be missing from the registers.

Basing our analysis on the register data provided, in the second half of 2011 there were 1.94 million active internet subscriptions used by private individuals, and there were 2,58 million households. I think that I consider the data from DIS129 to be more reliable than the data from VARFORBR; register data is usually better than survey data, although measurement error is always a potential problem. I also think an overestimate of the adoption rate resulting from the use of survey data, which is likely here given the discrepancy, is more plausible from a theoretical point of view than would be an underestimate; people participating in surveys are more likely to say that they have an internet connection even though they don’t than they are to say that they don’t have an internet connection even though they do. I also believe that this bias is likely to increase in people’s estimates of the ‘true’ penetrance rate; when you think everybody else have internet access you become less likely to admit that you don’t if you don’t. But there are multiple ways to explain the gap – for now perhaps the important point is that there is a gap, and that this should be kept in mind the next time the media talks about the results of the latest survey they’ve conducted (people rarely talk about the results of the latest register update…).

June 12, 2013 Posted by | data, demographics, statistics | Leave a comment

Daily Negations

“Daily Negations is exactly what the title suggests: a collection of negative thoughts, one for each day of the year. Like any other daily meditation books, it can be kept by the bed, on the coffee table or by the toilet. Daily Negations can be consulted first thing in the morning, or anytime during the day when a quick let-me-down is needed.

If you have a bleak view of life, Daily Negations will reinforce that view. The book may also be used by (or given to) people whose attitude in life is too sunny, too optimistic, too full of boundless strength and hope. Such people can come to a more normal, realistic world-view by daily consultation of Daily Negations.”

From the back cover of the book, which I’ve mentioned and quoted from once before. I gave the book a 5 star rating on goodreads, where the average rating is 4.56. A few more quotes below:

“Life doesn’t have to be something I actually live. Life can be something that happens while I am doing other things, like watching television or escaping into fantasy. The world won’t stop if I decide not to do anything. And it is easier not to do than to do. And the less I do, the less I can fail at.”

“All over the world, there are people much worse off than me who somehow manage to pick themselves up and go on. Their spirit should challenge and inspire me, but I prefer to believe that if they were in my position, they would be just as lazy and pathetic and useless as I am.”

“Each day brings me another 24 hours away from my youth. On the other hand, each day brings me 24 hours closer to my death. It will all be over before I know it.”

“In brief moments of clarity, it is plain to see that I can’t help myself, that no one else can help me and it will never get better. Fortunately, I am usually too deluded to ever face up to those simple truths.”

“Sometimes I console myself with the idea that even though I don’t do what I should do, at least I feel bad about it sometimes. At least I feel some guilt, and whenever I feel too much guilt, I can always overindulge in something that will distract me from my guilt, so that I dont’ really feel it. So I guess I’m really not very good at consoling myself.”

“I can see that it takes a lot of work to improve myself. Becoming the person I want to become will require enormous effort. I can recognize this, but I must always remember that deep down, I have no intention of doing what must be done: I won’t do anything today, and I probably won’t do anything tomorrow, or next week or next year. I will probably not improve very much, if at all. It is more likely that I will keep getting worse.”

“If I approach today with a negative attitude, I shouldn’t be surprised if things turn out badly. Similarly, if I approach today with a positive attitude, I shouldn’t be surprised if things turn out badly. As long as I’m alive, things will turn out badly.”

“Today will be a great day. Not for me of course—for me, it will be mediocre or terrible. But for somebody else, it will be an excellent day. I wish I were someone else. It sucks to be me.”

“Perhaps when I die, it will disappoint people who were counting on me. Perhaps something, or someone, will have trouble going on without me. Most likely though, my death won’t make any difference at all. Just like my life.”

“When I think of all the advantages I have had, I can feel even worse about how little I have accomplished. That is why it is so important to me to lie to myself, and tell myself that things were harder than they actually were, and that the obstacles in my way were not, for the most part, of my own making, and that all things considered, I did the best I could. These lies make me feel that I am better than other people (or at least as good), and that in turn makes me feel better about myself. It is so important to lie.”

“One thing I do is compare myself to other people: people I went to high school with who are more successful than I am, people in magazines and on TV who are better looking and more talented than I am, people at work who are smarter than I am and get promoted above me, and so on. I don’t like to do this, but I can’t help it, because I can’t control my bad habits, because I am an idiot.”

“Sometimes I think I’d like to get away for a while. But no matter where I go, there I am. There’s no escaping me. I might as well stay here.”

“There is no need to make excuses for myself when I make mistakes. Excuses involve creativity and energy. If I am too lazy and stupid to do something right, then I should be too lazy and stupid to explain myself.”

“Today I should try to do something I have never done before. Sometimes it is better to fail at something new, rather than to fail at the same old things.”

“Life may be looked at as a series of opportunities, but it is more accurate to look at life as a series of missed opportunities.”

This is great stuff! You can order the book here.

June 10, 2013 Posted by | books | 2 Comments


If you have any alternatives, especially ones which involve not-unpleasant interaction with other people, you should not follow these links or watch this stuff. Go interact with other people instead. Have fun, (try to) enjoy life. If you enjoy this kind of stuff, you’re likely doing things wrong and you’ll probably end up unhappy.

Tet offensive.

Arrest and assassination of Ngo Dinh Diem.

Genetically Modified Crops and Food Security.

War of 1812.

Tichborne case.

Geoguessr. It’s quite fun. My best score so far is 13165 (but who cares?).

June 9, 2013 Posted by | history, Khan Academy, Lectures, medicine, Pharmacology, Physics, random stuff, wikipedia | Leave a comment

Carpe Jugulum

As I believe I’ve pointed out before, the witch-books aren’t among my favourites; but there’s no such thing as a bad Discworld novel. Some quotes from the book, which I read yesterday and gave 3 stars on goodreads (where the average rating is 4.03):

“The people of Lancre wouldn’t dream of living in anything other than a monarchy. They’d done so for thousands of years and knew that it worked. But they’d also found that it didn’t do to pay too much attention to what the King wanted, because there was bound to be another king along in forty years or so and he’d be certain to want something different and so they’d have gone to all that trouble for nothing. In the meantime, his job as they saw it was to mostly stay in the palace, practise the waving, have enough sense to face the right way on coins and let them get on with the ploughing, sowing, growing and harvesting. It was, as they saw it, a social contract. They did what they always did, and he let them.”

“do you know what I found him doing in the old dungeons last week?’
‘I’m sure I couldn’t guess,’ said the Count.
‘He had a box of spiders and a whip! He was forcing them to make webs all over the place.’
‘I wondered why there were always so many, I must admit,’ said the Count.”

“cutting off the head and staking them in the heart is generally efficacious.’
‘But that works on everyone,’ said Nanny.
‘Er … in Splintz they die if you put a coin in their mouth and cut their head off …’
‘Not like ordinary people, then,’ said Nanny, taking out a notebook.
‘Er … in Klotz they die if you stick a lemon in their mouth—‘
‘Sounds more like it.’
‘—after you cut their head off. I believe that in Glitz you have to fill their mouth with salt, hammer a carrot into both ears, and then cut off their head.’ […]
‘And in the valley of the Ah they believe it’s best to cut off the head and boil it in vinegar.'”

“The result would have been called primitive even by people who were too primitive to have a word yet for ‘primitive’.”

“The local coachman used to warn visitors, you see. “Don’t go near the castle,” they’d say. “Even if it means spending a night up a tree, never go up there to the castle,” they’d tell people. “Whatever you do, don’t set foot in that castle.” He said it was marvellous publicity. Sometimes he had every bedroom full by 9 p.m. and people would be hammering on the door to get in. Travellers would go miles out of their way to see what all the fuss was about.”

“The castle gates swung open and Count Magpyr stepped out, flanked by his soldiers.
This was not according to the proper narrative tradition. Although the people of Lancre were technically new to all this, down at genetic level they knew that when the mob is at the gate the mobee should be screaming defiance in a burning laboratory or engaged in a cliffhanger struggle with some hero on the battlements.
He shouldn’t be lighting a cigar.
They fell silent, scyths and pitchforks hovering in mid-shake. The only sound was the crackling of the torches.
The Count blew a smoke ring.
‘Good evening,’ he said, as it drifted away. ‘You must be the mob.’
Someone at the back of the crowd, who hadn’t been keeping up to date, threw a stone. Count Magpyr caught it without looking.
‘The pitchforks are good,’ he said. ‘I like the pitchforks. As pitchforks they certainly pass muster. And the torches, well, that goes without saying. But the scythes … no, no, I’m afraid not. They simply will not do. Not a good mob weapon, I have to tell you. Take it from me. A simple sickle is much better. Start waving scythes around and someone could lose an ear. Do try to learn.’
He ambled over to a very large man who was holding a pitchfork.
‘And what’s your name, young man?’
‘Er … Jason Ogg, sir.’
‘The blacksmith?’
‘Wife and family doing well?’
‘Er … Yessir.’
‘Good man. Carry on. If you could keep the noise down over dinner I would be grateful …”

“‘You look like a priest. What’s your god?’
‘Er … Om.’
‘That’s a he god or a she god?’
‘A he. Yes. A he. Definitely a he.’ It was one thing the Church hadn’t schismed over, strangely.”

“‘But you can hardly stand up!’
‘Certainly I can! Off you go.’
Oats turned to the assembled Lancrastians for support.
‘You wouldn’t let a poor old lady go off to confront monsters on a wild night like this, would you?’
They watched him owlishly for a while just in case something interestingly nasty was going to happen to him.
Then someone near the back said, ‘So why should we care what happens to monsters?’
And Shawn Ogg said, ‘That’s Granny Weatherwax, that is.’
‘But she’s an old lady!’ Oats insisted.
The crowd took a few steps back. Oats was clearly a dangerous man to be around.”

“He could just make out her face. It was a picture, but not one you’d hang over the fireplace.”

“Verence was technically an absolute ruler and would continue to be so provided he didn’t make the mistake of repeatedly asking Lancrastians to do anything they didn’t want to do.”

June 8, 2013 Posted by | books, Terry Pratchett | Leave a comment

Chromosomal abnormalities..

I finished Peter Jensen’s book, which I also mentioned in the previous post, this morning, and I decided to add a few comments and links to articles covering stuff he also covers in his book. I liked the book and gave it 3 stars on goodreads. It’s old – from 1998 – so a lot of stuff has happened since then in this field (e.g. ‘new’ genetic diseases, such as 17q21.31 microdeletion syndrome, have been ‘discovered’ – though I should caution here that according to Jensen a distinction is to be made between ‘chromosomal abnormalities’ and ‘genetic diseases’; unlike many genetic disorders, chromosomal abnormalities involve mutations which are large enough to be seen using an ordinary light microscope). However my working assumption has been that most of the stuff covered in the book is unlikely to have changed much; how a chromosomal abnormality affects the individuals who have it doesn’t change much from one decade to another, even though improvements in medical technology may have improved outcomes for some specific diseases.

Some links to stuff he talks about in the book, in no specific order: Chromosome abnormality (I should add that pretty much every link in that article is to an article on something which is also covered in the book), Aneuploidy, Robertsonian translocation, Klinefelter syndrome, Turner Syndrome, Williams Syndrome, Down Syndrome, Patau syndrome, Fragile X syndrome, Angelman Syndrome, Prader-Willi syndrome, Barr body, Non-disjunction, Amniocentesis, Trisomy 8, FMR1.

A few general remarks: It should be noted that autosomal chromosomal abnormalities are usually more severe than sex-linked chromosomal abnormalities. More than 95% of chromosomal abnormalities result in spontaneous abortion, and 60% of early spontaneous abortions (within the first trimester) are due to chromosomal abnormalities. Monosomies (including partial ones) tend to have more severe consequences than do trisomies. Even though people tend to think that way about genetic diseases not all chromosomal abnormalities are best thought of as inhabiting a binary event space (either you have it or you don’t); some of them display to a significant extent a dose–response relationship (see e.g. the articles on the FMR1 gene & Fragile X syndrome). As should be obvious from the number of associated abortions, many of the chromosomal abnormalities (particularly the autosomal ones) lead to really horrible outcomes: Among Pataus Syndrome sufferers less than 40% survive past [remember: 1998 numbers] one week after birth, and only 4,5% survive past 6 months [according to wikipedia’s article on the topic, “More than 80% of children with Patau syndrome die within the first year of life” – so mortality is still very high]; when it comes to Edward’s syndrome likewise approximately 60% died within a week, and around 5% were still alive after a year back then – and this is just considering the variable survival, not stuff like blindness, polydactyli, organ malformation (brain, heart, kidneys, …), deafness, etc., etc., which are also very often present in people with these disorders…

Incidentally I read most of Carpe Jugulum today, but I won’t blog that one until tomorrow.

June 7, 2013 Posted by | books, genetics, medicine | Leave a comment

A Game of Thrones (II)

I finished the book. I gave it a 5 star rating on goodreads, where the average rating is 4.43. It’s a good book. I was considering whether it should have four or five stars, but in the end I decided that I probably give too few books 5 stars and this one kept me reading for many enjoyable hours, so…

It should go without saying that the second half is no worse than the first half; in retrospect it’s a natural plot development (some of it you can probably see coming, other things…), and Martin is quite good at this plot development stuff; after having read 800 pages you sort of feel that this story has only just really begun.

I’ll most likely read A Clash of Kings sometime this summer, but I won’t start reading that one this afternoon. I have yet to decide if I should start watching the tv-series before reading the second book, or if I should wait – I’ll probably wait. Anyway, these books are entertainment, not learning, and I feel a little bit guilty about not really having learned anything at all during the last few days; so I think I’ll read Kromosomafvigelser hos mennesket (‘Chromosomal abnormalities in humans’) by Peter Jensen next. I need a breather and this is my way to ‘breathe’. As that book is in Danish I’m not sure if I’ll cover it here in any detail, but I may say a word or two about it later on. I bought it on a sale (for 20 kroner ~$4..) and if it hadn’t been on sale I probably wouldn’t have bought it – there’s certainly no way I would have paid more than 100 kroners for it. I expect to finish it in a short amount of time as it’s quite short and as this is not the first book I read which deals with this topic.

June 6, 2013 Posted by | books | 2 Comments

A Game of Thrones

By George R. R. Martin. I had an exam yesterday (which went well, thanks for asking..), and after the exam I decided that I just wanted to take time off and read something I didn’t have to read; something I actually wanted to read because I assumed the reading experience would be enjoyable. A friend recommended this (book) series and I’ve also been made aware that there’s a tv-series I may want to give a try.

I’ve read half of the book (400 pages) by now and I expect to finish it sometime tomorrow. I also have procured A Clash of Kings, the next book in the series, and if I’m not disappointed during the last half of this book I’ll move on to read that as well sometime soon.

It’s a very good read so far but/and that’s mainly due to the storyline and the imaginary world Martin has created for us; the greatest problem I have with the book is the fact that there are a lot of people to keep track of and that it’s not always easy to figure out right away which ones are ‘important enough’ for you to need to need to remember them and who they are and what their uncle did in that war a long time ago. But that said, this is not a major problem, and the stuff is interesting even though you can’t always quite remember just who this particular guy is; the major characters reappear again and again so you gradually familiarize yourself with the characters even though they’re sometimes a bit hard to keep track of. I find it hard to illustrate the page-turner aspect of this book with quotes, but below I’ve added a few quotes from the first half anyway:

“Daenerys said nothing. She had always assumed that she would wed Viserys when she came of age. For centuries the Targaryens had married brother to sister, since Aegon the Conqueror had taken his sisters to bride. The line must be kept pure, Viserys had told her a thousand times […] yet now Viserys schemed to sell her to a stranger, a barbarian. […] “Are you sure tha Khal Drogo likes his women this young?” [Daenerys is 13] “She has had her blood. She is old enough for the khal,” Illyrio told him, not for the first time. […] “We go home with an army, sweet sister. With Khal Drogo’s army, that is how we go home. And if you must wed him and bed him for that, you will.” He smiled at her. “I’d let his whole khalasar fuck you if need be, sweet sister, all forty thousand men, and their horses too if that was what it took to get my army.”” [these last words were said by Viserys, the older brother of Daenerys – from what I’ve read so far, he seems like a very nice guy…]

[Her son (7 years old) lies paralyzed in a bed nearby, unconscious. The (‘bastard’) son of her husband, who has lived with the family all his life and been considered a brother by this woman’s young children, visits in order to say goodbye as he’s leaving the castle very soon, in all likelihood for the rest of his life. The last thing the woman says to him before he leaves:] “”It should have been you,” she told him.” [As in, she’d wish he was the one who’d broken his back and lay unconscious in that bed. And I still believe she’s actually supposed to be one of the sympathetic characters in this story, though as you can probably gather these things are complicated too…]

“Sansa did not really know Joffrey yet, but she was already in love with him. He was all she ever dreamt her prince should be, tall and handsome and strong, with hair like gold. She treasured every chance to spend time with him, few as they were. […] All she wanted was for things to be nice and pretty, the way they were in the songs. Why couldn’t Arya [her sister] be sweet and delicate and kind, like Princess Myrcella? She would have liked a sister like that.”

“As the others took their accustomed seats, it struck Eddard Stark forcefully that he did not belong here, in this room, with these men. He remembered what Robert had told him in the crypts below Winterfell. I am surrounded by flatterers and fools, the king had insisted. Ned looked down the council table and wondered which were the flatterers and which were the fools. He thought he knew already.”

“”Your sister sits beside the king. Your brother is a great knight, and your father the most powerful lord in the Seven Kingdoms. Speak to them for us. Tell them of our need here. You have seen for yourself, my lord. The Night’s Watch is dying. Our strength is less than a thousand now. Six hundred here, two hundred in the Shadow Tower, even fewer at Eastwatch, and a scant third of those fighting men. The Wall is a hundred leagues long. Think on that. Should an attack come, I have three men to defend each mile of wall.” […] He was in deadly earnest, Tyrion realized. He felt faintly embarrased for the old man. Lord Mormont had spent a good part of his life on the Wall, and he needed to believe if those years were to have any meaning. “I promise, the king will hear of your need,” Tyrion said gravely, “and I will speak to my father and my brother Jaime as well.” And he would. Tyrion Lannister was as good as his word. He left the rest unsaid; that King Robert would ignore him, Lord Tywin would ask if he had taken leave of his senses, and Jaime would only laugh.”

“”the common people are waiting for him. Magister Illyrio says they are sewing dragon banners and praying for Viserys to return from across the narrow sea to free them.” “The common people pray for rain, healthy children, and a summer that never ends,” Ser Jorah told her. “It is no matter to them if the high lords play the game of thrones, so long as they are left in peace.” He gave a shrug. “They never are.”

“”Is there a man in your service that you trust utterly and completely?””Yes,” said Ned.
“In that case, I have a delightful palace in Valyria that I would dearly love to sell you,” Littlefinger said with a mocking smile. “The wise answer was no, my lord, but be that as it may. […]
“Lord Petyr,” Ned called after him. “I … am grateful for your help. Perhaps I was wrong to distrust you.”
Littlefinger fingered his small beard. “You are slow to learn, Lord Eddard. Distrusting me was the wisest thing you’ve done since you climbed down off your horse.”

“I will not keep you long, my lord. There are things you must know. You are the King’s Hand, and the king is a fool.” […] “Your friend, I know, yet a fool nonetheless … and doomed, unless you save him. Today was a near thing. They had hoped to kill him during the melee.”
For a moment, Ned was speechless with shock. “Who?
Varys sipped his wine. “If I truly need to tell you that, you are a bigger fool than Robert and I am on the wrong side.”

“Varys will quietly let it be known that we’ll make a lord of whoever does in the Targaryen girl.”
Ned was disgusted. “So now we grant titles to assasins?”
Littlefinger shrugged. “Titles are cheap. The Faceless Men are expensive. If truth be told, I did the Targaryen girl more good than you with all your talk of honor. Let some sellsword drunk on visions of lordship try to kill her. Likely he’ll make a botch of it, and afterward the Dothraki will be on their guard. If we’d sent a Faceless Man after her, she’d be as good as buried.”
Ned frowned. “You sit in council and talk of ugly women and steel kisses, and now you expect me to believe that you tried to protect the girl? How big a fool do you take me for?”
“Well, quite an enormous one, actually,” said Littlefinger, laughing.
“Do you always find murder so amusing, Lord Baelish?”
“It’s not murder I find amusing, Lord Stark, it’s you. You rule like a man dancing on rotten ice.”

June 5, 2013 Posted by | books | 7 Comments