Econstudentlog

“What Darwin said” – evolution in a nutshell

7 links: 1, 2, 3, 4, 5, 6 and 7. Read them all. HT: Razib Khan. If you don’t already know about his blog, follow this link and start reading; the scienceblog-gnxp is definitely on my current top five of all blogs I read.

You can of course, rather than following these links, also just read Darwin himself here (I have given you this link before some time ago, but in case someone missed it: Here you can find a Danish translation of On the Origin of Species…).

For the record, I value the opinions of people denying evolution’s views about the biological sciences about as highly as I value the medical opinions of people still subscribing to the miasma theory of disease. The parallel is not completely randomly chosen: On the Origin… came out in 1859, only 5 years after Filippo Pacini as the first man ever isolated a bacterium, the Vibrio cholerae bacillus which causes cholera, thus invalidating the miasma theory of disease. One of the main reasons why there aren’t many people who are convinced that the latter theory is correct anymore, is that that particular theory never made it into the churches.

October 30, 2009 Posted by | evolution, genetics, religion | Leave a comment

College degrees and gender

Since 1970, the gender ratio has flipped:

collegedegrees

Only business, engineering and the physical sciences have more males than females enrolled. Via Mark Perry.

October 27, 2009 Posted by | data, demographics, education, USA | Leave a comment

Diabetes, international prævalens og lidt mere om mortalitet

Jeg ville egentligt have gjort dette til en mere bred post om sundhedsdata, men jeg kom til at gå ud ad en tangent, og posten herunder er så, hvor jeg havnede. Først et kig på diabetesprævalensen i et internationalt perspektiv:

diabetes prevalens

diabetes prevalens 2

Jeg vidste ikke på forhånd, om jeg ville skrive posten på dansk eller engelsk, så jeg valgte at konstruere graferne på engelsk, anyway… De første to lande er Australien og Østrig, SR er Slovakiet, Kor er (Syd)korea – jeg håber de øvrige giver sig selv, ellers spørg. Kilden er OECD, rådata kan findes her. Der er også meget mere data af samme type ved dette link til OECD’s sample over helbredsrelaterede nøgleindikatorer, som jeg også tidligere har linket til.

Bemærkelsesværdigt for mange vil det nok være, at USA end ikke er i nærheden af at være i toppen af listen over diabetesrater. Jeg ved ikke om det er opgørelsesmetoden, der spiller ind her, men dette er i hvert fald overraskende. Mange lande, i dette udsnit Schweiz, Mexico, Ungarn, Canada, Tyskland, Tjekkiet og Østrig, har højere absolut prevalens, og de fleste af de samme lande ligger ligeledes på niveau eller højere i de alderskorrigerede data (her skiller især Mexico sig ud fra resten). Bemærk at mellemindkomstlande i efterhånden nogle år har oplevet stor vækst i incidensen af type 2 diabetes, og at både Kina og Indien i disse år også oplever voldsom vækst. Livsstilssygdomme holder sig ikke længere til de rige lande.

Jeg fandt også nedenstående interessant (data er fra OECD’s nøgleindikatorer):

diabetes dødsfald

Pr. 100.000 indbyggere er på en måde en god variabel, på en måde en dårlig variabel at anvende. Den er god, fordi den angiver en form for (meget) løst estimat for, hvor udbredt sygdommen er (ja, det, der måles, er hvor mange, der dør af sygdommen; men disse to variable følges altså ret godt ad – det må synes en rimelig antagelse, at ‘den marginale nydiagnosticerede diabetiker’ ikke vil introducere væsentlige nye effekter af interesse på populationsniveau, som vil lede til signifikante afvigelser på mortalitetsraterne på tværs af diabetespopulationen som helhed på langt sigt, selvom han eller hun rigtigt nok gør på kort sigt, se også ndf.). Den er dårlig, fordi den overser modsatrettede effekter, som i perioden utvivlsomt har spillet en rolle. Hvis man ønskede kun at fange mortalitetsudviklingen og således prøve at omgå problemet prævalensvariationen (-væksten) over tid udgør, ville døde pr. 1000 diabetikere eller lignende være et bedre mål, selvom det selvfølgelig også er problematisk at anvende, eksempelvis fordi risikoen for komplikationer vokser over tid og derfor på ingen måde er homogen i gruppen af diabetikere, et forhold mortalitetsstudierne altid tager (og bør tage) højde for.

Det er vanskeligt at sammenligne tallene fra 1960 med tallene fra i dag, for mange ting har ændret sig, og en del af disse har utvivlsomt medvirket til at gøre det problematisk at sammenligne tallene over tid uden at tage nogle betydelige forbehold. Det giver mening, at flere i dag dør af diabetes, fordi flere i dag har diabetes, men for bare at tage tre markante problemer, så a) har patologernes praksis ændret sig i perioden, b) diabetes var mere dødelig for 50 år siden, end sygdommen er i dag, fordi vores viden om sygdommen og vores behandlingsmuligheder er udvidet markant, og c) det er uklart, hvor stor forskel de markante fremskridt i diagnosticeringsprocessen (måling af glykeret hæmoglobin, brugen af plasma-glukose værdier), såvel som de deraf følgende ændrede diagnostiske praksis, har betydet for disse tal. Tallene er i den meget lave ende, og det vil de fleste af den slags opgørelser være: Mange diabetesdødsfald er vanskelige at kategorisere den ene eller den anden vej. Mere end 80 % af diabetikerne herhjemme dør af hjertekar-sygdom, men det er umuligt for en patolog at vide med sikkerhed, om hr. Hansen fik sin blodprop pga. sin diabetes, eller om han havde fået den alligevel. Hvis tallene stammer alene fra eksempelvis dødsårsagsregistret, vil de undervurdere diabetes’ betydning for mortaliteten betydeligt, en observation der for øvrigt er righoldig empirisk belæg for at gøre sig (Mühlhauser, Sawicki m.fl.). Observationen betyder også, at der nok i opgørelser som disse vil være en tendens til kun at anvende/acceptere diabetes som dødsårsag i de mest oplagte tilfælde (de mest oplagte vel nok værende DKA, diabetisk hypoglykæmi (estimeret 2-4% af alle dødsfald blandt diabetikere), hyperosmolær non-ketotisk koma og nyresvigt sekundær til diabetes), og så se bort fra diabetes som forklaringselement i tilfælde som er vanskeligere at kategorisere.

Hvis man holder sig alene til disse tal, koster diabetes lidt under 900 mennesker livet herhjemme hvert år, ud af ca. 55.500 døde i alt – det omtrentlige tal for 2006, det sidste år hvor data er tilgængelige i OECD-regi, jf. dst – svarende til ca. 1.6 %. Det tal er meget, meget lavt, og estimaterne på dette område varierer da også ganske betydeligt. Den internationale diabetesforening IDF estimerede således tidligere dette efterår, at 2.744 danskere i 2010 vil dø på grund af diabetes (linket er her – men det er en elendig artikel, og jeg vil anbefale dig ikke at følge linket, da det estimat er omtrent artiklens eneste ‘formildende omstændighed’, så at sige). Det estimat er måske tættere på sandheden, men der er som sagt mange usikkerhedselementer her som gør evaluering af sådanne estimater vanskelig.

October 27, 2009 Posted by | data, diabetes | Leave a comment

John Hawks and Razib Khan on bloggingheads, part 2

I loved their first video, and this one is just as great. Hawks is a really great communicator and he does an excellent job in these videos, whereas Razib manages to ask a lot of the right questions. I highly recommend you to watch at least the first 45 minutes of this episode.

Vodpod videos no longer available.

more about “BH episode (Hawks and Khan)“, posted with vodpod

October 19, 2009 Posted by | anthropology, archaeology, science | Leave a comment

Obama’s “New Era of Responsibility”

Chart_9-24-09

The September 08 projections were made before Obama was elected, the January projections were made about the same time he was inaugurated (January 20th) whereas the most recent August projections were made after he’d have time to actually make policy. These projections are not based on the estimates of some obscure right-wing partisans; rather the numbers are provided by the CBO. Potential healthcare reforms (…/spending bills) are not included in these numbers.

Link, via the mercatus twitter.

October 17, 2009 Posted by | data, economics, Obama | 4 Comments

Efterårsferielæsning

i) Formel logik, af Stephen Read og Crispin Wright. Det er en introduktionsbog til formel logik, som formodentligt anvendes på filosofistudiet – jeg faldt over bogen i Stakbogladen. Har læst de første par kapitler, den er ok indtil videre. Det er ikke oplagt at citere fra den. Jeg har altid været lidt træt af, at jeg nærmest ingen undervisning har haft i dette emne på noget tidspunkt i mit liv (vi berørte nærmest end ikke overfladen i filosofi i gymnasiet), og det, at jeg nu læser denne bog, er en måde at råde lidt bod på dette forhold. Bogen havde formodentligt været en god støtte at have ved hånden, da jeg i sin tid læste Karl Poppers LoSD, især i forhold til de relativt tekniske appendixes, som jeg gerne skal indrømme, at jeg ikke læste i deres helhed.

ii) King Lear, af William Shakespeare. Har anskaffet mig en et-binds udgave af hans samlede værker på omtrent 1100 sider, og er startet ud der. Naturligvis på originalsproget. Har ikke læst ret meget endnu, i hvert fald ikke nok til at udtale mig nærmere på nuværende tidspunkt.

iii) Robin Lane Fox. Stadig et stykke vej endnu. Stadig spændende.

iv) 639 Essential Endgame Positions, af Eric Schiller. Jeg mangler seriøst noget slutspilsviden, og denne bog er et forsøg at rette lidt op på det forhold. Læser stadig Polgar ved siden af, er mere end 10% færdig nu (600 problemer løst); men den bog er, som jeg vurderer det, primært et redskab til bedring af de taktiske færdigheder. Ikke at den ikke også samtidig er et fremragende redskab til at.gøre dig langt bedre bekendt med de enkelte brikkers potentiale og styrker din generelle stillingsforståelse betydeligt, det gør den såmænd også. Jeg har læst relativt lidt ikke-netbaseret skakteori, men jeg tror nok, jeg på nuværende tidspunkt er nået et punkt, hvor det vil være kontraproduktivt ikke at sætte sig lidt grundigere ind i spillets mange facetter, hvis jeg ønsker at forbedre mit spil over tid, og det gælder vel nok især, pga. min spillestil og mit temperament, slutspilsniveauet. Der er kun så meget Fritz kan hjælpe med. Jeg har undret mig over Schiller’s opbygning af bogen, der er noget kontraintuitiv og også lidt irriterende (hvis man ønsker at evaluere afledte varianter i konkrete analyser, er man ofte nødt til at hoppe frem og tilbage i bogen for at gøre det). Tror langt fra, at det er den bedste bog om emnet, men den er et skridt på vejen, og jeg er allerede blevet præsenteret for flere grundlæggende ideer, jeg ikke kendte til, i forhold til konkrete slutspilspositioner.

October 14, 2009 Posted by | bøger, skak | 3 Comments

Promoting the unknown, a continuing series

A few of Felix Blumenfeld‘s piano pieces. They are unfortunately not very well known. A shame, this is great stuff:

October 10, 2009 Posted by | music | Leave a comment

The Classical World (1)

I’ve mentioned the book a few times by now, but I haven’t gone into much detail. What I wrote in the first post in which I mentioned the book is a good, if very short, summary of what the book is all about: Ancient Greece and ancient Rome, 900 years, ~ 700 pages . From Homer to Hadrian.

I’ve only read the first 200 pages or so, so this is just a somewhat preliminary account. Robin Lane Fox’s book is not flawless, but I like his style. He is not trying to (pretend that he is…) write (…/writing) a 100 percent objective account of the matters he describes; on the contrary he often emphasizes his own views and opinions, very openly starting sentences with the words ‘in my opinion‘. I find his openness and honesty refreshing. You will most likely disagree with him on a number of things – which is a good thing, because measured disagreement makes you think.

On a methodological level, I’d have liked some more economics, some trade estimates, some data in general, but I know full well that those are very hard to come by. And would be mostly pure guesswork anyway. That said, Fox’ account is not in any way excessively centered on a few great individuals, he rather also does try to also give us some insights into “life as an ordinary greek”, even if it is hard to know all that much for certain about them (as Fox ie. openly tells us in the book, even in fourth-century Athens, we have no first-hand surviving evidence of conversations between husband and wife (p.190)). The book’s composition is great, with chapters long enough to cover the specific subject in question, but short enough to never let you miss ‘the big picture’ – the average length is 10 (densely packed) pages or so, with relatively little variation. I read about 30 pages/hour, with a relatively high reading comprehension (and a lot of painting and writing in the book) – this is not a book where you can read 80 pages/hour, definitely not if you want to actually learn and remember something from it. The book’s chronology is, as you’d expect, relatively unbroken, and on the chapter level it has so far progressed linearly. The chapters also all assume that you’ve read the previous one(s) and I believe you’d miss out on a lot if you were to skip specific chapters. Stated another way: This is in my opinion a book you’re really supposed to read from the first to the last page.

Below follow a few quotes from the book:

1) …What he [Solon] did do was to ban the bad practice of creditors who demanded their debtor’s free person as security for his debts. Most of these debts would be small and short-term, but they brought the debtor the accompanying risk of default, real or alleged: there was no idea of ‘collateral’ and as the security (a person) was so much more valuable, it was tempting for a creditor to foreclose unjustly. Debts thus led to the unacceptable enslavement of one Athenian by another (p.65)

Notice the word bad in the beginning of this quote, as well as the words unjustly. Fox is not trying to be 100% objective, but in most cases it doesn’t matter all that much. Apropos what should happen to debtors who defaulted on their loans, which probably should be considered a question meriting at least some interest today, here’s the Roman version (p.120):

It was […] a particular Roman precision to specify that a debtor who defaulted when owing debts to several people should be divided into pieces and distributed to each of his creditors.

From Rome’s Twelve Tables. Makes you think…

2) With two minor interruptions, this democracy persisted among the Athenians and evolved for more than a hundred and eighty years. In our terms, it was remarkably direct. It was not at all a ‘representative democracy’ which elected local representatives either to ‘represent’ their constituents or their own careers and prejudices. Its whole concern was to limit power-blocs or over-assertive cliques, to achieve fragmentation, not representation. (p.96, my emphasis)

3) For us, the most distinctive fact about the Athenian culture Herodotus visited is that it was a slave society. Some 55.000 adult male citizens owned some 80.000-120.000 other human beings, ‘objects’ whom they could buy and sell. These slaves (almost all non-Greeks) were central to the Athenians’ economy, working in the silver-mines (often down appallingly narrow tunnels) and also in agriculture where contemporary comedies present them to us as a normal part of quite modest Athenian families’ property. The prices of untrained slaves appear to have been low, because supply was abundant, from war or raids on barbarian Thrace or inland Asia Minor. […] However, Herodotus would not have remarked unduly on this fact of life. Slaves were andrapoda, ‘man-footed beasts’; they were ubiquitous in the Greek communities into whom Herodotus enquired. He never queried the justice of this fact. (p.143)

4) In public, a married Athenian woman was still [~ 450 BC] only called ‘the wife of…’; to use her own name would imply that she was a prostitute. In the late 340s we find an Athenian orator reminding a citizen-jury that ‘we have “courtesans” [hetairai] for pleasure, prostitutes for everyday attention to our bodies and wives for the production of children legitimately and for being a trustworthy guardian of the contents of the household.’ […] Those Athenian males who could afford all three types of woman would have agreed with the orator in question, while adding that in youth (and, perhaps, still), they had young boys for competitive pursuit, idealization and quick sexual pleasure without the risk of a baby. They never met an educated Athenian woman, because no women were taught in an Athenian school with the boys. (p.144-145)

October 7, 2009 Posted by | anthropology, books, history | Leave a comment

Books and a game

The last week has been somewhat slow here. I don’t feel much like blogging at the moment, but I feel a bit bad about it when I don’t update regularly, so another chess game must be better than nothing. As always, follow the link – I was black.

My opening choice was a little, unorthodox, but he’d just played the Stonewall against me – and if you want to piss me off, that sure is a great way to do it, especially if you combine it with systematic and deliberate lag. I would never have played ie. 11.Bb6 if I hadn’t been angry – it was a deliberate sack, not a blunder, but never the less a dubious sack I wouldn’t have made otherwise – however pretty much every single move I make after that is on the Fritz short-list.

On a completely different note, I have now completed both of Pratchett’s books. Going Postal is the best of them, but both are well worth reading and if you like Going Postal, you’ll no doubt like Making Money too. Lane Fox’s book is great so far, but I still have a long way to go. I will probably bring a few quotes from the book in next couple of days, if I can find the time and motivate myself to do so (as always, I make no promises).

October 6, 2009 Posted by | books, Chess, history | Leave a comment