Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Testing an agent-based model of bacterial cell motility: How nutrient
  concentration affects speed distribution   We revisit a recently proposed agent-based model of active biological motion
and compare its predictions with own experimental findings for the speed
distribution of bacterial cells, \emph{Salmonella typhimurium}. Agents move
according to a stochastic dynamics and use energy stored in an internal depot
for metabolism and active motion. We discuss different assumptions of how the
conversion from internal to kinetic energy $d(v)$ may depend on the actual
speed, to conclude that $d_{2}v^{\xi}$ with either $\xi=2$ or $1<\xi<2$ are
promising hypotheses. To test these, we compare the model's prediction with the
speed distribution of bacteria which were obtained in media of different
nutrient concentration and at different times. We find that both hypotheses are
in line with the experimental observations, with $\xi$ between 1.67 and 2.0.
Regarding the influence of a higher nutrient concentration, we conclude that
the take-up of energy by bacterial cells is indeed increased. But this energy
is not used to increase the speed, with 40$\mu$m/s as the most probable value
of the speed distribution, but is rather spend on metabolism and growth.

25
The categories of this paper are: patt-sol
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
3
The categories of this paper are: physics
22
The categories of this paper are: chao-dyn
19
The categories of this paper are: eess
21
The categories of this paper are: adap-org
32
The categories of this paper are: atom-ph
13
The categories of this paper are: quant-ph
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci