GUTS_RED_IT: GUTS-RED-IT scenario

In cvasi: Calibration, Validation, and Simulation of TKTD Models

GUTS-RED-IT scenario

Description

Reduced General Unified Threshold models of Survival (GUTS) with individual tolerance (IT).

Usage

GUTS_RED_IT(param, init)

Arguments

param	optional named list or vector with model parameters
init	optional named numeric vector to use as initial state

Value

an S4 object of type GutsRedIt

Simulation output

The return value of simulate() will contain values for the state variables, as well as an additional column S which represents the survival probability for each time point. S is calculated as described in EFSA (2018) as S = (1- F(t)). The background hazard rate hb is already considered in state variable H and therefore does not occur as an additional term to derive S.

State variables

The following list describes the default names and standard units of GUTS-RED state variables:

• D, scaled damage (conc)

• H, cumulative hazard (-)

The state variables are initialized with zero by default.

IT model parameters

• kd, dominant rate constant (time^-1)

• hb, background hazard rate (time^-1)

• alpha, median of thresholds (conc)

• beta, shape parameter (-)

Effects

The effect endpoint L (lethality) is available for GUTS-RED models. A value of zero (0.0) denotes no effect on organism survival. A value of one (1.0) denotes a lethality rate of 100%, i.e. no survivors.

The survival probability S is available in the return value of simulate().

References

EFSA PPR Panel (EFSA Panel on Plant Protection Products and their Residues), Ockleford C, Adriaanse P, Berny P, et al., 2018: Scientific Opinion on the state of the art of Toxicokinetic/Toxicodynamic (TKTD) effect models for regulatory risk assessment of pesticides for aquatic organisms. EFSA Journal 2018; 16(8):5377, 188 pp. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.2903/j.efsa.2018.5377")}

See Also

Other GUTS-RED models: GUTS-RED-models, GUTS_RED_SD()

cvasi documentation built on Sept. 23, 2024, 9:08 a.m.