Learn More
We have compared the sublethal effects of two insecticides in the honeybee (imidacloprid and deltamethrin) in both semi-field and laboratory conditions. A sugar solution containing 24 microg kg(-1) of imidacloprid or 500 microg kg(-1) of deltamethrin was offered to a colony set in an outdoor flight cage. In contrast to imidacloprid, deltamethrin had lethal(More)
The concept that computers can be creative in designing new molecules is now being actively explored. Our work has been aimed at developing an intercommunicating hybrid system using a genetic algorithm and a backpropagation neural network model for solving the general problem of designing molecules with specific properties. A case study dealing with(More)
SUMMARY A new method combining graphical displays with principal component analysis (PCA) has been used to evaluate published data on the toxicity of seven chemicals to 14 species (17 testing procedures) of aquatic biota. The results show the usefulness of simple graphical approaches to analyze the structure of environmental data sets. Thus, the study(More)
Losses of foraging bees are sometimes attributed to altered flight pattern between a meliferous plant treated with an insecticide and the hive. Only a limited number of studies has investigated the impact of pesticides on homing flight due to the difficulty of measuring the flight time between the food source and the hive. Monitoring the flights of the(More)
The family of adaptive resonance theory (ART) based systems concerns distinct artificial neural networks for unsupervised and supervised clustering analysis. Among them, the ART 2-A paradigm presents numerous strengths for data analysis. After a rapid presentation of the ART 2-A theory and algorithmic information, the usefulness of this neural network for(More)
The OECD has proposed five principles for validation of QSAR models used for regulatory purposes. Here we present a case study investigating how these principles can be applied to models based on Kohonen and counter propagation neural networks. The study is based on a counter propagation network model that has been built using toxicity data in fish fathead(More)
  • H Zhang, Y Yang, J Devillers, A T Balaban, Gordon Breach, Amsterdam +8 others
  • 2007
The Wiener index of a graph is the sum of distances between all pairs of vertices. A toroidal polyhex (or toroidal graphitoid) H (p, q, t) can be described by a string (p, q, t) of three integers (p ≥ 1, q ≥ 1, 0 ≤ t ≤ p-1). In a recent work (MATCH 45 (2002) 100-122) M.V. Diudea obtained Wiener index formulae for several classes of toroidal nets, including(More)
The contamination of the eggs of farmland birds by currently used plant protection products (PPPs) is poorly documented despite a potential to adversely impact their breeding performance. In this context, 139 eggs of 52 grey partridge Perdix perdix clutches, collected on 12 intensively cultivated farmlands in France in 2010-2011, were analysed. Given the(More)
An attempt was made to derive structure-activity models allowing the prediction of the larvicidal activity of structurally diverse chemicals against mosquitoes. A database of 188 chemicals with their activity on Aedes aegypti larvae was constituted from analysis of original publications. The activity values were expressed in log 1/IC50 (concentration(More)
The potential effects of pesticides and their metabolites on the endocrine system are of major concern to wildlife and human health. In this context, the azole pesticides have earned special attention due to their cytochrome P450 aromatase inhibition potential. Cytochrome P450 aromatase (CYP19) catalyses the conversion of androstenedione and testosterone(More)