These parameters behave like parameters that were collected: you can display them, calculate statistics on them, etc. It is important to note that although newly derived parameters are not added to the original data file, they can become part of a new data file if you choose to Export your file(s). This will eliminate the need to recreate the parameter(s) when using the data in a different workspace.

Common Uses:

Ratio: Division can be used to calculate a ratio of any two collected parameters. This is commonly necessary for calcium flux experiments, in which the ratio of Indo-1 fluorescence in two different channels is related to the calcium concentration. You can choose to create a ratio parameter with either linear or logarithmic scaling.

Add Gain or Offset: Adjust your data’s display arithmetically. Insert the Reference parameter, and then choose to multiply or add each value by any number to move the data points towards or away from 0.

Lin/Log Conversion: Change scale by selecting Linear or Log from the Scale drop-down menu. It is easier to use the ‘T’ button in the graph window to do this much quicker.

Zoom: Use Scaling to restrict the range of your plots to identify minor fluctuations in your histogram plots. Select a Reference parameter and then enter Min and Max values for the range. By pressing Preview, your mono-variate plot can be previewed. It is easier to use the ‘T’ button in the graph window to do this much quicker.

Functions Available:

FlowJo provides a suite of mathematical functions to assist your analysis, described briefly below.

Basic functions:

+ (Addition) : combine parameters together

/ (Division) : calculate a ratio of parameters

% (Modulus) : the remainder of the division of one parameter by another (a.k.a modulo)

* (Multiplication) : scaling one parameter by another

– (Subtraction) : the inverse of addition

Value functions:

abs (Absolute value) : the numerical value of a parameter without regard to its sign

ceil (Rounded up value) : determines the smallest integer not less than the specific reference

floor (Rounded down value) : determines the largest integer not greater than the specific reference

neg (Negate) : reverses the sign of the parameter values

max (Maximum value) : largest value that a parameter takes

min (Minimum value) : smallest value that a parameter takes

round (rounded value) : replace a numerical value with one that is shorter, simpler, and approximately equal

Power functions:

pow [Exponentiation] : multiplication repeated by the number of times set by the power

exp [e^ exponentiation] : the mathematical constant e multiplied by itself the number of times set by the power

ln [Natural logarithm] : logarithm to the base e

log [Base 10 logarithm] : logarithm to the base 10

sqrt [Square root] : of a number a is a number such that y^2=a

Trigonometry functions:

acos [Arc cosine] : inverse cosine

asin [Arc sine] : inverse sine

atan [Arc tangent] : inverse tangent

cos [cosine] : of an angle is the ratio of the length of the adjacent side to the length of the hypotenuse

cosh [Hyperbolic cosine] : analog of cosine for hyperbola

sin [Sine] : of an angle is the ratio of the length of the opposite side to the length of the hypotenuse.

sinh [Hyperbolic sine] : analog of sine for hyperbola

tan [Tangent] : of an angle is the ratio of the length of the opposite side to the length of the adjacent side

tanh [Hyperbolic tangent] : analog of tangent for hyperbola