This Test Guideline lists methods for determining the density of liquids and solids, giving only a very succinct description of them. The density of a substance is the quotient of its mass and its volume and is expressed in kg/m3. Several methods are for liquid substance only: hydrometer,...

The bacterial reverse mutation test uses amino-acid requiring at least five strains of Salmonella typhimurium and Escherichia coli to detect point mutations by base substitutions or frameshifts. The principle of this bacterial reverse mutation test is that it detects mutations which revert...

Dominant lethal (DL) effects cause embryonic or foetal death. Induction of a dominant lethal event after exposure to a test substance (liquid, solid, vapour or gas, …) indicates that the substance has affected germinal tissue of the test species. Dominant lethals are generally accepted to be...

This Test Guideline describes methods to measure the viscosity of liquids. The methods listed are appropriate in principle for the investigation of Newtonian liquids. The measurement of non-Newtonian liquids is only possible with the rotational viscometer. Viscosity measurements are carried out...

This Test Guideline describes a method which is an adaptation of the Soap and Detergent Association semi-continuous activated sludge (SCAS) procedure for assessing the primary biodegradation of alkyl benzene sulphonate. The test does not simulate those conditions experienced in a sewage...

In many countries a new concept is emerging as an alternative to command-and-control regulation: the concept of shared responsibility between governments and businesses. Governments and businesses are seeing a need for co-operation and partnership, rather than confrontation and adversarial...

While most 15-year-old students spend part of their after-school time doing homework, the amount of time they spend on it shrank between 2003 and 2012. Socio-economically advantaged students and students who attend socio-economically advantaged schools tend to spend more time doing homework....

Education is the key to economic, social and environmental progress, and governments around the world are looking to improve their education systems. The future of education in the 21st century is not simply about reaching more people, but about improving the quality and diversity of educational...