Martijn Cloos
Bio [2006]
Currently Martijn is pursuing his master's degree in biomedical physics at
Amsterdam University. Apart from biomedical physics, he also has a strong
interest in theoretical physics and tries to combine both fields whenever
possible. With a small group of people from his university, he makes
educational material
about science for children.
Project Title
Modeling Folding Caused by Growth
Project
In nature there are systems that will fold while growing. Here I look at a
model that captures some of the basics of this behavior using only a
simple set of rules. I compare the results to observations in biology and
chemistry, in particular to folding caused by cell growth and molecular
bonding.
The model is based on a network substitution system. There are two
different types of nodes, represented by black and white. The black nodes
are active and can divide into three new nodes creating a new cell. A
totalistic rule determines how nodes are substituted.
The cell representations in this model are simple surfaces that are
bounded by edges and have no internal edges. The shape of the cells is not
preserved during the evolution. Cells must have similar dimensions, so
cells are rescaled by connecting their centers of mass with all their
nearest first neighbors. The connections are then laid out in
three-dimensional space using a spring model. This is then used to
construct the 3D shape.
Favorite Four-Color, Radius-1/2 Rule
Rule chosen: 260
In the space of left-handed, range-1/2, four-color CA I like rule 260
because it is exactly the same as rule 60 from the ECA. For any binary
initial condition, rule 260 is the smallest of a superset of 1048576 rules
that all have this behavior. The largest rule number in this set is
4294963460. The set is formed by taking all the possible numbers
##########010010 from base 4 (# is a number in range 0-3). When you plot
the table of numbers without sorting them you can see the pattern caused
by the base for the enumerating system.
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