| When you open the Options button in the
kinetics window, you are shown the following options to modify the
attributes of the current graph (or currently-selected gate).
From this window, you control all of the parameters
that can be displayed in the kinetics graph.
The functions that can be displayed are each calculated
on the Y parameter for each time interval across the entire graph.
FlowJo selects an appropriate time interval over which to calculate
the function values (usually, this value is 1 channel of the time
parameter). After the function is computed, any smoothing that has
been selected is applied; the result is graphed in the window. TheY
axis scaling is also defined in this window: either automatic (FlowJo
scales the Y axis so that the minimum and maximum values of the
graph will be onscale); or, you can set the minimum and maximum
Y axis values manually.
The possible functions that can be displayed are:
- Median: the median fluorescence of the events
in each time interval
- Mean: the mean fluorescence of the events in
each time interval
- Geometric mean: Same as mean for linear Y parameters;
otherwise, it is average of the channel values converted to the
scale of the Y parameter.
- Percentile: An arbitrary percentile of the events
in each time interval. Entering 50 in the percentile value generates
the same graph as "Median."
The remaining functions are computed based on a
threshold value. The threshold is a scale value of the Y axis parameter
(i.e., not the channel value, but the scaled linear fluorescence
value). The threshold can either be an absolute value, or a relative
value based on time slices that you have defined (see information
on defining thresholds).
The first threshold function is just the fraction
of events that are above the threshold for each time interval. If
you were to define a certain threshold fluorescence value as the
minimum for a cell to be considered a "responding" cell,
then the resulting graph would show you the fraction of cells responding
as a function of time. Each of the other functions gives you the
appropriate statistic calculated only on the cells above the threshold
value. Thus, you could, for example, plot the median fluorescence
of responding cells to eliminate the averaging in of non-responding
cells.
The two possible smoothing functions are "moving
average" and "Gaussian". They are similar; the Gaussian
smoothing places less weight on values more distant from the center.
The smoothing width defines approximately how many time intervals
are averaged for each displayed time interval; a smoothing width
of 1 implies 3 time intervals are averaged for each point.
Go to the overview on Kinetics.
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