A Home for Complex Systems Science

In complex systems science, the notion of complexity is often summarized with the phrase “the whole is more than the sum of its parts“. This expression can be traced all the way back to the early Greek philosopher Aristotle (Metaphysics, Book VIII, 1045a.8-10) and mathematician Euclid (Elements, Book I, Common Notion 8). It was therefore appropriate to have a conference on complex systems in Greece. As part of a delegation from the Institute for Advanced Study of the University of Amsterdam, I attended this conference to learn more about recent advances in complex systems science, and about some ancient Greek history. Read more

Workshop Report: Developmental Biases in Evolution

“Developmental bias is a manifestation of a much more fundamental principle, and is the norm rather than the exception”, according to one scientist. “Developmental bias is a misleading term and we should get rid of it”, according to another. Both were in the same room, at the same time. So what is developmental bias, what role does it play in evolution, and why do we even care? These questions were the focus of an interesting and spirited workshop, the third in a series of EES project meetings, held recently at the Santa Fe Institute. As with the first meeting, I was able to sit in on this workshop, like a fly on the wall, and listen to the presentations, arguments, and debates. Here’s what I learned…

Read the full piece on the EES Blog

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

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.

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!

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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.

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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…

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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.

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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

Dutch Deserts

With on average more than 180 days with rain annually (that’s roughly every other day!), and a total of more than 800mm of rainfall every year, one certainly would not expect to find a desert in The Netherlands. However, there are actually several areas in the country where you can walk through perfect white-sand landscapes. Interestingly, the cause of this goes back several ice ages.

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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.

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

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.

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