SigmaTransformed: SigmaTransformed
In aravind-j/viabilitymetrics: Seed Viability Calculations and Curve Fitting

Description Usage Arguments Details Value References See Also Examples

SigmaTransformed transforms the measured sigma value at a specific temperature to an estimate of sigma at another temperature. This useful in comparitive seed testing protocol to compare seed longevities among species tested at different temperatures \insertCiteprobert_ecological_2009viabilitymetrics. \loadmathjax

1	SigmaTransformed(sigma, temp1, temp2, temp.coeff = c(0.0329, 0.000478))

`sigma`	The inverse of slope from the seed viability equation (\mjseqn\sigma), estimated at temperature `temp1`.
`temp1`	The temperature at which `sigma` is estimated in °C.
`temp2`	The temperature at which the transformed \mjseqn\sigma is to be estimated in °C.
`temp.coeff`	The species-specific temperature coefficients (\mjseqnC_H and \mjseqnC_Q.) as a numeric vector of length 2.

The transformation is based on the effect of temperature on seed longevity (\mjseqn\sigma) (identified by storage experiment with constant moisture content and varying temperature) which is as follows.

\mjsdeqn\log\sigma

= \beta - C_Ht - C_Ht^2

Where, \mjseqnC_H and \mjseqnC_Q are the species-specific temperature coefficients, \mjseqnt is the temperature and \mjseqn\beta is the constant associated with moisture relations of seed longevity.

The transformed value of \mjseqn\sigma at temperature temp2.

\insertRef

ellis_improved_1980viabilitymetrics

\insertRef

probert_ecological_2009viabilitymetrics

Sigma