The Cascades Raptor Center


The Cascades Raptor Center, Eugene, Oregon (image credit)

I am currently travelling in the US, and recently dropped in at the Cascades Raptor Center in Eugene, Oregon (see the Raptor Center website and Raptor Center instagram). This is primarily a hospital and rehabilitation centre for injured raptors (eagles, hawks, falcons, ospreys, owls, vultures, etc.). By my count, 37 birds are on public display in wire mesh aviaries (mostly birds too seriously injured to be released).

Admission is US$10 per adult, and there is a small gift shop. Viewing the birds takes about an hour, and I really enjoyed my visit (the Center would also appeal to children of all ages). Tripadvisor gives the Center 4½ stars, which is probably a little more than I would give, given the Center’s size (but the money supports the Center’s work). There are also more interactive night-time viewing events, which I did not experience.


Ferruginous hawk (Buteo regalis) and Gyrfalcon (Falco rusticolus) at the Raptor Center (photographs by Anthony Dekker)


Pi Day!

Pi Day is coming up again (3/14 as a US date). The number π is, of course, 3.14159265… Here are some possible activities for children:

  • Search for your birthday (or any other number) in the digits of π
  • Follow in the footsteps of Archimedes, showing that π is between 22/7 = 3.1429 and 223/71 = 3.1408.
  • Calculate 333/106 = 3.1415 and 355/113 = 3.1415929, which are better approximations than 22/7.
  • Measure the circumference and diameter of a round plate and divide. Use a ruler to measure the diameter and a strip of paper (afterwards measured with a ruler) for the circumference. For children who cannot yet divide, try to find a plate with diameter 7, 106, or 113.
  • Calculate π by measuring the area of a circle (most simply, with radius 10 or 100), using A = πr2. An easy way is to draw an appropriate circle on a sheet of graph paper.

You can also try estimating π using Buffon’s needle. You will need some toothpicks (or similar) of length k and some parallel lines (such as floorboards) a distance d apart (greater than or equal to k). Then the fraction of dropped toothpicks that touch or cross a line will be 2 k / (π d), or 2 / π if k = d. There is an explanation and simulator here (see also the picture below). And, of course, you can bake a celebratory pie and listen to Kate Bush singing π, mostly correctly!

This picture by McZusatz has 11 of 17 matches touching a line, suggesting the value of 2×17/11 = 3.1 for π (since k = d).

Actually, of course, π = 3.1415926535 8979323846 2643383279 5028841971 6939937510 5820974944 5923078164 0628620899 8628034825 3421170679 8214808651 3282306647 0938446095 5058223172 5359408128 … (digits in red are sung by Kate Bush, accurately, although some have said otherwise).


Looking back: 2001

The 1968 film 2001: A Space Odyssey suggested that we would have extensive space flight in 2001. That turned out not to be the case. What we did get was the September 11 attacks on the USA and the military conflicts which followed. Nevertheless, NASA commemorated the film with the 2001 Mars Odyssey orbiter.

Films of 2000 included the superb The Lord of the Rings: The Fellowship of the Ring, several good animated films (including Monsters, Inc., Shrek, and Hayao Miyazaki’s Spirited Away), the wonderful French film Amélie, some war movies (Enemy at the Gates was good, but Black Hawk Down distorted the book too much for my taste), the first Harry Potter movie, and an award-winning biographical film about the mathematician John Nash.

In books, Connie Willis published Passage, one of my favourite science fiction novels, while Ian Stewart explained some sophisticated mathematics simply in Flatterland.

Saul Kripke (belatedly) received the Rolf Schock Prize in Logic and Philosophy for his work on Kripke semantics, while Ole-Johan Dahl and Kristen Nygaard (also belatedly) received the Turing Award for their work on object-oriented programming languages (both these pioneers of computing died the following year).

The year 2001 also saw the completion of the Cathedral of Saint Gregory the Illuminator in Armenia, which I have sadly never visited.

In this series: 1978, 1980, 1982, 1984, 1987, 1989, 1991, 1994, 2000, 2001, 2004, 2006, 2009.


Rods and cones in the human eye

I already posted these images (click to zoom) on Instagram. They illustrate the sensitivity to colour of the rods (lower right) and the three types of cones in the human eye. Cone sensitivity data is from CVRL.

Notice that red light is pretty much invisible to the rods. This is why red light does not interfere with night vision, and is used in e.g. this aircraft cockpit:


Eurovision Song Contest and GDP

Following up on my previous post and the one before that, here is some more analysis of Eurovision Song Contest voting for this year. There are some interesting correlations between national tele-votes (not jury votes) and demographic variables, especially per capita GDP. As the map above shows, this is essentially a proxy for the northwest–southeast axis.

Iceland came 4th with the song 10 Years in spite of never actually competing; a positive COVID-19 test result restricted the band to their hotel; and they were judged based on a tape of their rehearsal performance. The richer Nordic countries seem to have been especially generous in this situation (see chart below).

Conversely, the winning song from Italy received generally lower tele-votes from the richer countries (I am not entirely sure why):

The song Je me casse from Malta came 7th overall. As with Iceland, the higher tele-votes came from the richer countries, although the pattern here is fuzzier than for Iceland. There are also some notable outliers: the Australian tele-vote of 8 for Malta probably reflects the 176,000 people of Maltese descent living in Australia.

Russia shows a pattern somewhat similar to Italy (p < 0.004, R2 = 22%), but this is simply because the former Soviet countries that vote for Russia are also the poorer ones. A better predictor can be obtained by counting Russian expatriates (p < 0.001, R2 = 44%).

And finally, here is a plot of tele-vote totals against jury vote totals. They differ substantially:


Eurovision Song Contest: More Analysis

Following up on my previous post, here is some more analysis of Eurovision Song Contest voting for this year. The maps above show a hierarchical clustering analysis on tele-voting (above) and jury voting (below), based on calculating simple Euclidean distance between vote vectors and on an assumption that countries would give themselves 12 points if they could. Some key differences between the four main clusters are highlighted in colour (note that Azerbaijan, Israel, the Netherlands, and the UK clustered alone or in a pair):

Tele-voting cluster 1 (green)

Countries: Australia, Belgium, Denmark, Estonia, Finland, Germany, Iceland, Ireland, Italy, Latvia, Lithuania, Malta, Norway, Poland, Sweden, and Ukraine.

Average votes:  Italy:  8, Iceland:  8, Ukraine:  8, Finland:  8, Lithuania:  8, France:  6, Switzerland:  4, Sweden:  4, Norway:  4, Malta:  2, Russia:  2, Serbia:  1, Belgium:  1, Albania:  1, Germany:  1, Greece:  0, Cyprus:  0, and Moldova:  0.

Tele-voting cluster 2 (purple)

Countries: Austria, Bulgaria, Croatia, North Macedonia, Serbia, Slovenia, Spain, and Switzerland.

Average votes:  Italy:  10, Serbia:  10, France:  8, Switzerland:  6, Ukraine:  6, Finland:  5, Iceland:  4, Russia:  2, Bulgaria:  2, Greece:  2, Azerbaijan:  2, Albania:  2, Spain:  2, Malta:  1, Lithuania:  1, Portugal:  1, Cyprus:  1, and Moldova:  0.

Tele-voting cluster 3 (red)

Countries: Albania, Czech Republic, France, Moldova, Portugal, and Romania.

Average votesMoldova:  10, Ukraine:  9, Italy:  8, France:  8, Switzerland:  6, Finland:  4, Greece:  4, Russia:  3, Portugal:  3, Iceland:  2, Sweden:  2, Albania:  2, Lithuania:  1, Bulgaria:  1, Israel:  1, Azerbaijan:  1, Serbia:  0, and Cyprus:  0.

Tele-voting cluster 4 (yellow)

Countries: Cyprus, Georgia, Greece, Russia, and San Marino.

Average votes:  Italy:  10, Greece:  9, Cyprus:  9, France:  7, Ukraine:  6, Finland:  4, Russia:  4, San Marino:  4, Lithuania:  3, Switzerland:  2, Bulgaria:  2, Moldova:  2, Azerbaijan:  2, Malta:  1, Albania:  1, Iceland:  0, and Serbia:  0.

Check out the disputed songs: Iceland: 10 Years, Lithuania: Discoteque, Serbia: Loco Loco, Moldova: Sugar, Greece: Last Dance, and Cyprus: El diablo.

The map below shows jury voting. For jury voting, there were only two substantial clusters (i.e. containing 4 or more countries – Albania, Malta, Romania, France, Israel, Norway, Sweden, Belgium, and Italy clustered alone or in small clusters of 2 or 3 countries).

Jury voting cluster 1 (purple)

Countries: Australia, Austria, Croatia, Czech, Denmark, Estonia, Finland, Georgia, Germany, Iceland, Ireland, Latvia, Lithuania, Netherlands, NM, Poland, Portugal, Serbia, Slovenia, Spain, Switzerland, Ukraine, and UK.

Average votesSwitzerland:  9, Iceland:  8, France:  7, Italy:  6, Malta:  4, Bulgaria:  4, Portugal:  4, Ukraine:  3, Finland:  3, Lithuania:  2, Russia:  2, Israel:  2, Belgium:  2, Greece:  1, Sweden:  1, Serbia:  1, Cyprus:  1, Azerbaijan:  1, San Marino:  1, Netherlands:  1, Spain:  1, Germany:  1, UK:  1, and Moldova:  0.

Jury voting cluster 2 (red)

Countries: Azerbaijan, Bulgaria, Cyprus, Greece, Moldova, Russia, and San Marino.

Average votesGreece:  9, Moldova:  8, Malta:  7, Bulgaria:  7, Italy:  6, France:  6, Russia:  6, Cyprus:  4, Azerbaijan:  4, San Marino:  3, Portugal:  2, Belgium:  2, Switzerland:  1, Iceland:  1, Ukraine:  1, Finland:  1, Lithuania:  1, Sweden:  1, Israel:  1, and Spain:  1.

Check out the disputed songs: Switzerland: Tout l’Univers, Iceland: 10 Years, Greece: Last Dance, and Moldova: Sugar


Eurovision Song Contest 2021

The Eurovision Song Contest has been on again (strangely, Australia is now part of Europe). On the whole, I didn’t think much of the songs this year, although there were a few gems (like the French entry).

This (revised) chart shows those tele-votes which were surprisingly high, given the total scores (country colours indicate total scores, with grey for non-finalists). Arrows reflect high tele-votes (in a relative sense). Red arrows reflect particularly high tele-votes (in a relative sense), including:

  • Austria, Croatia, North Macedonia (NM), Slovenia, and Switzerland Serbia (Balkan cluster)
  • North Macedonia (NM) and Italy Albania (ditto)
  • Cyprus Greece Cyprus (as usual)
  • Netherlands Greece (the Greek singer resides in the Netherlands)
  • Georgia Greece
  • Russia Cyprus
  • Moldova Russia (former USSR)
  • Czech Republic and Romania Moldova
  • Latvia, Germany, Norway, UK, and Ireland Lithuania
  • Denmark and Iceland Sweden (Nordic cluster)
  • Sweden, Iceland, and Estonia Finland (ditto)
  • Malta Norway
  • Azerbaijan Israel

Regional sentiment and expatriate voting still play a part, I see. Here is the same network overlaid on a map:


Houston, we have a problem

Some years ago, I posted the chart above, inspired by a classic XKCD cartoon. The infographic above shows the year of publication and of setting for several novels, plays, and films.

They fall into four groups. The top (white) section is literature set in our future. The upper grey section contains obsolete predictions – literature (like the book 1984) set in the future when it was written, but now set in our past. The centre grey section contains what XKCD calls “former period pieces” – literature (like Shakespeare’s Richard III) set in the past, but written closer to the setting than to our day. He points out that modern audiences may not realise “which parts were supposed to sound old.” The lower grey section contains literature (like Ivanhoe) set in the more distant past.

The movie Apollo 13 has now joined the “former period piece” category. Released in 1995, it described an event of 1970, 25 years in the past. But the ill-fated Apollo 13 mission of 11–17 April 1970 is now 51 years in the past; the movie is closer to the event than it is to us (although the phrase “Houston, we have a problem” – in real life, “Houston, we’ve had a problem” – has become part of the English language).

The image shows the real-life Apollo 13 Service Module, crippled by an explosion (left), together with a poster for the 1995 movie (right). Maybe it’s time to watch it again?


A Narnian Timeline

I’ve been on a bit of a Narnia binge recently. Continuing that theme, here is a timeline of the Chronicles of Narnia (click to zoom). The Terran time axis has varying scales (although piecewise linear), since 5 of the 7 Narnia books (53% of Narnian history) are set during 1940–1942. For simplicity, I also assume a piecewise linear mapping of Narnian time to Terran time (see graph below), although the text of the books indicate that the mapping is more complex than that. For Narnian events in the chart, only the vertical position has meaning (the sideways curve is only there to create space).

The Crucifixion of Jesus is included as a significant Terran event, since its Narnian parallel is the key event of The Lion, the Witch and the Wardrobe. Some scholars date this to the year 30, rather than 33.

The chart was produced using R. The curved lines are plotted with colours from colorRampPalette(). Images were added using png::readPNG, as.raster(), and rasterImage(), with circles using plotrix::draw.circle(). For the title, the extrafont package was used.