Data output

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Track number
Time
X
Y
Vx
Vy
V
Angle
Ax
Ay
A

The number of the track
Calibrated time
Calibrated X coordinate (origin is top left)
Calibrated Y coordinate (origin is top left)
Calibrated and averaged velocity in x direction (top to bottom)
Calibrated and averaged velocity in y direction (top to bottom)
Length of the calibrated and averaged velocity vector
Angle of the velocity vector
Calibrated and averaged acceleration in the x direction
Calibrated and averaged acceleration in the y direction
Length of the calibrated and averaged acceleration vector

Cluster of cultured bacteria swarming around an algal cell. The bacterial are responding to the oxygen gradient created by the algal cell. Tracked over 16 seconds, containing 930 runs. Scale bar, 50 µm. From Blackburn et al 1998.

Analysis of the clustered bacteria shown above. Radial components of run lengths relative to the algal cell (center of source) are plotted as a function of distance, separated into those moving toward and away from the source (up and down gradients). Run lengths were closely Poisson distributed. From Blackburn et al 1998.