SSsharp: self start for temperature response

In nlraa: Nonlinear Regression for Agricultural Applications

self start for temperature response

Description

Self starter for temperature response function

Usage

sharp(temp, r_tref, e, el, tl, eh, th, tref = 25)

SSsharp(temp, r_tref, e, el, tl, eh, th, tref = 25)

Arguments

temp	input vector (x) which is normally ‘temperature’.
r_tref	rate at the standardised temperature, tref
e	activation energy (eV)
el	low temperature de-activation energy (eV)
tl	temperature at which the enzyme is half active and half suppressed due to low temperatures
eh	high temperature de-activation energy (eV)
th	temperature at which enzyme is half active and half suppressed dut to high temperatures
tref	standardisation temperature in degrees centigrade. Temperature at which rates are not inactivated by either high or low temperatures. Typically, 25 degrees.

Details

For details see Schoolfield, R. M., Sharpe, P. J. & Magnuson, C. E. Non-linear regression of biological temperature-dependent rate models based on absolute reaction-rate theory. Journal of Theoretical Biology 88, 719-731 (1981)

Value

sharp: vector of the same length as x using a sharp function

Note

I do not recommend using this function.

Examples

require(ggplot2)
require(minpack.lm)

temp <- 0:45
rate <- sharp(temp, 1, 0.03, 1.44, 28, 19, 44) + rnorm(length(temp), 0, 0.05)
dat <- data.frame(temp = temp, rate = rate)
## Fit model
fit <- nlsLM(rate ~ SSsharp(temp, r_tref, e, el, tl, eh, th, tref = 20), data = dat)
## Visualize
ggplot(data = dat, aes(temp, rate)) + geom_point() + geom_line(aes(y = fitted(fit)))

nlraa documentation built on July 9, 2023, 6:08 p.m.