Persistence of Simple Substances

A simple persistence condition for structured populations.

The fundamental question in both basic and applied population biology of whether a species will increase in numbers is often investigated by finding the population growth rate as the largest eigenvalue of a deterministic matrix model. For a population classified only by age, and not stage or size, a simpler biologically interpretable condition can be used, namely whether R0, the mean number of ...

A simple screening method for insecticidal substances from actinomycetes.

A simple and selective assay system was developed in the search for new insecticidal substances from Actinomycetales strains propagated on solid culture media. The strains were first tested for their ability to produce antimicrobial compounds. Only strains displaying weak or no activity were retained and screened in the insecticidal bioassay. Microbial solid cultures were given as food to larva...

NEW SUBSTANCES: Model assessment of potential for long-range transboundary atmospheric transport and persistence of Endosulfan

New Concepts in the Evaluation of Biodegradation/Persistence of Chemical Substances Using a Microbial Inoculum

The European REACH Regulation (Registration, Evaluation, Authorization of CHemical substances) implies, among other things, the evaluation of the biodegradability of chemical substances produced by industry. A large set of test methods is available including detailed information on the appropriate conditions for testing. However, the inoculum used for these tests constitutes a "black box." If b...

Persistence in a Simple Model for Earth’s Atmosphere Temperature Fluctuations

The effect caused by the presence of a number of distinct time scales in a simple stochastic model for Earth’s atmosphere temperature fluctuations is studied. The model is described by a dissipative dynamics consisting of a set of coupled stochastic evolution equations. The system shows features that resemble recent observations. In contrast to other approaches, like autoregressive models, the ...