Expert Systems used in the identification of misconceptions and assessment in school science: a review and proposed development

From research carried out over the last 20 years, there is now a wealth of data on the identification of students' misconceptions in various topics within science education. Much of the data in the form of questions and students' answers, and analysis of the data is well documented. Within this same period there have been major developments in the programming and use of microcomputer based expert system shells which can use formalised expert knowledge to mimic the processes normally carried out by a human expert. It seems that the two areas of research could, in the fuure, be brought together to provide support for teachers in using the research findings to support the individualised and targeted teaching of students in the classroom. A recent literature search, however, has shown the dearth of activity in this field. This paper reviews the situation at the present time and suggests how the two activities could be united.     

Controlling fruit-shedding in the oil palm

The oil palm is a major factor in the economy of much of South East Asia and maximising the harvest is of major consequence. One important source of loss is the shedding of ripe fruit from the bunches before they reach the factories. Study of the course of abscission reveals unusual processes in the oil palm — and in a few other plantation crops such as dates and coconuts — which suggest practical means of achieving better harvesting regimes and regulation of fruit shedding.     

Epidemiological considerations of the history of indigenous malaria in Britain

Thanks to the intensive use of antimalarial drugs, of insecticides to destroy the mosquitoes that carry it, and of land drainage measures to eliminate their breeding grounds, the incidence of malaria worldwide has been very substantially reduced in recent years. In Britain it is today virtually unknown, save among those who have acquired it abroad. In the past, however, it was widely prevalent and the reasons for its decline are an interesting facet of social history.     

Resurgence of behavior during extinction depends on previous rate of response

In two experiments, food-deprived rat subjects leverpressed for food in three successive training phases. In the first phase of both experiments, rats were exposed to a multiple schedule, one component of which produced a high rate of response, and the other of which produced a lower rate of response (multiple random ratio [RR], random interval [RI] in Experiment 1, and multiple differential reinforcement of high rate, differential reinforcement of low rate in Experiment 2). Rats were then transferred to a multiple fixed interval (FI; 60-sec, 60-sec) schedule, until the effects of the first phase on response rate were no longer apparent and their response rates did not differ from those of rats responding on a multiple FI 60-sec, FI 60-sec schedule without previously experiencing a multiple RR, RI schedule. During the third stage oftraining, all rats were placed into extinction. During extinction, rates of responding were higher in the component previously associated with the high rate of responding in Phase 1, and they were lower in the component previously associated with low rates of responding in Phase 1. These results suggest that resurgence effects, like other history effects, are controlled by previous rates of responding.     

Effects of response-independent stimuli on fixed-interval and fixed-ratio performance of rats: a model for stressful disruption of cyclical eating patterns

Binge eating is often associated with stress-induced disruption of typical eating patterns. Three experiments were performed with the aim of developing a potential model for this effect by investigating the effect of presenting response-independent stimuli on rats’ lever-pressing for food reinforcement during both fixed-interval (FI) and fixed-ratio (FR) schedules of reinforcement. In Experiment 1, a response-independent brief tone (500-ms, 105-dB, broadband, noisy signal, ranging up to 16 kHz, with spectral peaks at 3 and 500 Hz) disrupted the performance on an FI 60-s schedule. Responding with the response-independent tone was more vigorous than in the absence of the tone. This effect was replicated in Experiment 2 using a within-subject design, but no such effect was noted when a light was employed as a disrupter. In Experiment 3, a 500-ms tone, but not a light, had a similar effect on rats' performance on FR schedules. This tone-induced effect may represent a release from response-inhibition produced by an aversive event. The implications of these results for modeling binge eating are discussed.