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{This paper presents a knowledge representation object language (KROL) on top of Prolog. KROL is aimed at providing the ability to develop second-generation expert systems. The main aspects of KROL include multi-paradigm knowledge representation (first-order predicate logic, objects, rules), inference mechanisms at different levels of granularity, explanation facility, object-oriented database management module, and user-friendly interface. KROL has sufficient expressive power to be used in applying demanding knowledge-based modeling methodologies, such as KADS and Generic Task, which are the major landmarks of the second-generation expert systems technology. Four successful agricultural expert systems have been developed in the last 6 years using KROL. To demonstrate the language capabilities, we present an example of disorder diagnosis.}

Apramycin was administered to chickens orally, intramuscularly and intravenously to determine blood concentration, kinetic behaviour, bioavailability and tissue residues. Single doses of apramycin at the rate of 75 mg kg-1 body weight were given to broiler chickens by intracrop, i.m. and i.v. routes. The highest serum concentrations of apramycin were reached 0.20 and 0.76 hours after the oral and i.m. doses with an absorption half-life (t1/2(ab.)) of 0.10 and 0.19 hours and an elimination half life (t1/2(beta)) of 1.22 and 2.31 hours respectively. The systemic bioavailability was 2.0 and 58 per cent after intracrop and i.m. administration, respectively, indicating poor absorption of the drug when given orally. Following i.v. injection, the kinetics of apramycin was described by a two-compartment open model with a (t1/2(alpha)) of 1.5 hours, (t1/2(beta)) of 2.1 hours. Vd(ss) (volume of distribution) of 4.82 litre kg-1 and C1(B) (total body clearance) of 1.88 litre kg-1 hour-1. The serum protein-binding of apramycin was 26 per cent. The highest tissue concentrations of apramycin were present in the kidneys and liver. No apramycin residues were detected in tissues after six hours except in the liver and kidneys following intracrop dosing and kidneys following i.m. administration.

A kinetic and thermodynamic study of the aerial oxidation of perphenazine is presented. The investigations involve factors that are likely to be operative under normal conditions of the storage of the drug in liquid formulations. The factors which have been investigated one at a time comprise, pH, dissolved oxygen, metal ions, solvent, ionic strength and temperature. The experimental results were discussed and the kinetic parameters evaluated at 60°C and 80°C were employed for the computation of the activation energy (E(a)(#)), enthalpy change (ΔH(#)) entropy change (ΔS(#)) and free energy change (ΔG(#)). The relevance of these thermodynamic parameters to the rate constant (k) of the reaction and the effect of the surface activity of perphenazine on the degradation:process have been discussed.