robustbase (version 0.95-1)

toxicity: Toxicity of Carboxylic Acids Data

Description

The aim of the experiment was to predict the toxicity of carboxylic acids on the basis of several molecular descriptors.

Usage

data(toxicity, package="robustbase")

Format

A data frame with 38 observations on the following 10 variables which are attributes for carboxylic acids:

toxicity

aquatic toxicity, defined as \(\log(IGC_{50}^{-1})\); typically the “response”.

logKow

\(log Kow\), the partition coefficient

pKa

pKa: the dissociation constant

ELUMO

Energy of the lowest unoccupied molecular orbital

Ecarb

Electrotopological state of the carboxylic group

Emet

Electrotopological state of the methyl group

RM

Molar refractivity

IR

Refraction index

Ts

Surface tension

P

Polarizability

References

Maguna, F.P., Núñez, M.B., Okulik, N.B. and Castro, E.A. (2003) Improved QSAR analysis of the toxicity of aliphatic carboxylic acids; Russian Journal of General Chemistry 73, 1792--1798.

Examples

data(toxicity)
summary(toxicity)
plot(toxicity)
plot(toxicity ~ pKa, data = toxicity)

## robustly scale the data (to scale 1) using Qn
(scQ.tox <- sapply(toxicity, Qn))
scTox <- scale(toxicity, center = FALSE, scale = scQ.tox)
csT <- covOGK(scTox, n.iter = 2,
              sigmamu = s_Qn, weight.fn = hard.rejection)
as.dist(round(cov2cor(csT$cov), 2))