Models for recall and recognition.
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Attention↗
Biomedical subjects
J G Raaijmakers
Publications and source records attributed to J G Raaijmakers.
Episodic memory in dementia of the Alzheimer type and in normal ageing: similar impairment in automatic processing.
A perceptual identification task was used to provide an implicit measure for automatic memory processes. The facilitation of word identification on repeated presentation is taken as a measure of the automatic retrieval of an episode. In addition, recognition memory was tested. The recognition task is an explicit test of memory and relies mainly on controlled processing. In the first experiment 11 patients suffering from probable Alzheimer disease and 11 normal age- and sex-matched controls were tested. Both groups exhibited a rather small facilitation effect (ca 7%) but did not differ in the size of the effect. However, when tested explicitly, a difference in recognition memory existed between the two groups. In the second experiment the performance of 11 normal young subjects was compared to that of 11 normal elderly subjects. Whereas the elderly group showed a small facilitation effect similar to that observed in the first experiment, a considerable facilitation effect was found for the young group. Also, the elderly group had poorer recognition memory than the young group.
Aged↗
Statistical analysis of the Michaelis-Menten equation.
An application of the method of maximum likelihood (ML) is described for analysing the results of enzyme kinetic experiments in which the Michaelis-Menten equation is obeyed. Accurate approximate solutions to the ML equations for the parameter estimates are presented for the case in which the experimental errors are of constant relative magnitude. Formulae are derived that approximate the standard errors of these estimates. The estimators are shown to be asymptotically unbiased and the standard errors observed in simulated data rapidly approach the theoretical lower bound as the sample size increases. The results of a large-scale Monte Carlo simulation study indicate that for data with a constant coefficient of variation, the present method is superior to other published methods, including the conventional transformations to linearity and the nonparametric technique proposed by Eisenthal and Cornish-Bowden (1974, Biochemical Journal 139, 715-720). Finally, the present results are extended to the analysis of simple receptor binding experiments using the general approach described by Munson and Rodbard (1980, Analytical Biochemistry 107, 220-239).
Analysis of Variance↗
System for the identification of novel prostaglandins.
A system for structural analysis based on thin-layer and gas chromatographic and mass spectrometric data is presented. It permits the rapid and unequivocal identification of structurally closely related prostaglandins and their products containing microbiologically introduced hydroxyl groups at positions C-16, -17, -18, -19, and -20. Novel criteria are described by which distinctions can be made between stereoisomers.
Chromatography, Gas↗