Funny clocks and counters…
Latest Posts
From an Ecologist’s Nightmare to a Mathematician’s Dream
“Since you are a computer scientist, I have an optimisation problem for you!”, my colleague said, half jokingly. As an ecologist, one of the things my colleague studies is invasive plant species. The question he was facing is how to reconstruct the most likely routes along which these species travel when they invade new territory, based on historical records on when and where they first appeared. As it turns out, this question is an instance of a known mathematical optimisation problem called the minimum cost arborescence problem.
Read the full story on Plus Magazine…
Whim of the Week – 64
Collect moments, not things…
Full Moon Above Thessaloniki
An (almost) full moon (98% illuminated) rising above Thessaloniki, Greece, as viewed from the balcony of my hotel room. A rather hazy evening, so no exceptional shots, but very beautiful to watch anyway! (Click each pic for a full-size view.)
The Evolution of Emergent Computation
Many systems in nature consist of a large number of relatively simple units that interact only locally, and without a central control, yet the system as a whole can perform sophisticated global information processing, or produce intricate globally coordinated behaviors. A well-known example of this is quorum sensing in microbial communities, where the basic units are bacteria.
Read the full story on TVOL.
Evolution Montpellier 2018
Evolutionary biology is a thriving field. This was exemplified very recently at the Second Joint Congress on Evolutionary Biology, held in Montpellier, France, from 19-22 August. Attended by around 2700 scientists, there were more than 800 contributed talks, distributed over 78 thematic symposia over the course of four days. This was certainly the largest evolutionary biology meeting ever organized so far.
Whim of the Week – 63
Funny traffic lights and beautiful castles.
La Cathedrale de Strasbourg
I spent a morning strolling around the old town of Strasbourg, France, with as main goal a visit to its impressive cathedral. Unfortunately it was a completely overcast day, so the sky was white instead of blue. But in some way it actually made the whole experience even more mystical!
A Chalk Walk
Among scientists, a “chalk talk” means a lecture without a laptop and beamer to display fancy graphics, but simply using a blackboard and a piece of chalk to draw diagrams and formulas while you speak. It’s sort of going back to the basics to force you to explain your topic clearly. Last week I also went back to the basics, leaving my laptop behind to go on a 5-day walking trip through Zuid-Limburg, the southernmost area of The Netherlands. This region is well known for its extensive layers of limestone, and the 90km walking path I followed is appropriately called Krijtlandpad, or chalkland path. It was indeed a beautiful “chalk walk”, also highlighting many of the other things the region is famous for, including the country’s highest point.
Lunar Eclipse over Amsterdam
Last night there was a (complete) lunar eclipse which was visible from Amsterdam. Many thanks to Jo & Piet for sharing their 9th-floor apartment balcony with me, from where the views were just wonderful! Here are some impressions. Click any of the pics for a full-size view…
Whim of the Week – 62
Beauty is cruelty…
Complex Experimental Autocatalytic Sets
Autocatalytic sets are self-sustaining chemical reaction networks which are believed to have played an important role in the origin of life, and to be an underlying principle of living systems in general. They have been studied in great detail both mathematically and with computer simulations, and actual experimental examples have been constructed in the lab. However, so far these experimental examples were of a limited complexity (so-called “elementary” autocatalytic sets). Recently, though, a group of researchers have constructed and studied the first experimental example of a more complex (“non-elementary”) autocatalytic set.
The Evolutionary Roots of Irrationality
Standard economic theory assumes that humans behave fully rationally and are able to objectively calculate the value (or cost) of the different choices they are presented with. In fact, we pride ourselves on our rationality. Different from the animals, we humans have the unique capacity for logical thought and rational decision making. Or do we?
Read the full piece on This View of Life…
Whim of the Week – 61
A whimsical garage owner…
Citizen Science: Schumann Resonances
Schumann resonances (SR) are global electromagnetic resonances generated by lightning in the cavity between the Earth’s surface and the ionosphere. Their existence was predicted mathematically in 1952. However, it took another decade before they could be reliably measured and verified. Given that Schumann resonances occur in the same electromagnetic frequency spectrum as human brain waves, it has been suggested that extreme fluctuations in these resonances could affect human behavior and health.
Read the full story at Plus magazine.
Whim of the Week – 60
A poem about mathematics…
Snooker Statistics Follow Precise Mathematical Laws
A particular mathematical relationship known as a power law has been observed in many day-to-day situations, from word use frequencies in natural languages to the connectivity distribution in Facebook friendship networks. As it turns out, though, such a power law can also be found in snooker statistics. And if the amazing Ronnie O’Sullivan produces yet a few more centuries, the mathematical correspondence will be even better! Read more
Whim of the Week – 59
Frolicking frogs and slithering snakes…
Impressions of Amsterdam
I’ll admit it straight away: it’s not my city, and it never will be. But on one of those rare blue-sky days it’s actually not so bad (if you can manage to dodge the hordes of tourists, that is). Here are some impressions from around the old town of Amsterdam, in the area where I currently live and work.
Whim of the Week – 58
Snails do it too!
Update: Earthquake Statistics
A year ago I published an article in Plus magazine debunking claims buzzing around the internet about a supposed recent increase in earthquakes and volcanic eruptions and so on. In that article I showed in detail how anyone can analyze publicly available data to put such claims to the test. In the current post, I present a brief update on earthquake statistics, showing that there still is no need to worry.
Tracing the Roots of my Family Name
It’s quite fun when your family name originates from a specific place that still exists and can be visited. As had already been known for a long time, my family name comes from a street, the Hordijk, in a neighborhood that is now in the southern part of the city of Rotterdam. So, on a sunny Saturday afternoon, I decided to go and pay a visit to this place where my ancestors once lived…
Whim of the Week – 57
Room for rent…
Evolution as a Problem Solver in Computer Science
The theory of evolution has helped biologists and ecologists to understand more about the natural world in general, and psychologists and social scientists to understand more about ourselves in particular. However, it has also taught a thing or two to computer scientists.
Read the full story on This View of Life…
What’s Your Problem?
Some problems are fundamentally hard, not only for humans, but even for computers. We may know how to solve these hard problems in theory, but in practice it might take billions of years to actually do so, even for the fastest supercomputer.
Read the full story on Plus magazine…