Dresden 2017 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 34: Posters - Physics of Physarum polycephalum and Other Slime Molds (Focus Session)

BP 34.2: Poster

Dienstag, 21. März 2017, 14:00–16:00, P2-OG1

Inexpensive Observation System for Decision Experiments with Physarum polycephalum — •Ann-Marie Parrey¹, Nelly von Puttkamer^1,2, Anja Bammann¹, Adrian Fessel¹, Erik Bernitt¹, and Hans-Günther Döbereiner¹ — ¹Institut für Biophysik, Universität Bremen — ²Hochschule Bremen

A low-priced observation system with automated temperature control and image capturing is presented. The setup is controlled by a Raspberry Pi and can be used for educational purposes. We demonstrate that with this system, the decision-making behaviour of slime molds such as Physarum polycephalum can be automatically observed.

Over a period of 24 hours a Raspberry Pi camera module inside the incubator takes pictures of a slime mold growing on an agar plate composed of two sides. One side contains a threat, i.e. salt, while the other side is neutral. The slime mold is prepared on an oatmeal flake and sits in the middle of the agar plate. Varying salt concentration, we observe a strong preference of the slime mold towards the neutral side for high salt concentrations, while this preference weakens for low concentrations. This behaviour can be explained assuming a two state system, where the salt side is represented by a higher energy state and the neutral side is associated with a lower energy state. With these assumptions, the probability P_N(c) to find the slime mold on the neutral side can be calculated: P_N(c)=1/(e^−kc+1) , with c as the salt concentration and a constant k, which is fit to the data. We find theoretically that k = 1/Ω   ∂Ω/∂ c, i.e. the relative loss of the number of states Ω with increasing salt concentration.