Aflatoxin in maize: a review of the early literature from "moldy-corn toxicosis" to the genetics of aflatoxin accumulation resistance.

Aflatoxin is a potent toxin produced by Aspergillus flavus Link:Fr, an opportunistic ear-rot pathogen of maize (Zea mays L. subsp. Mays). Prior to the discovery of aflatoxin, A. flavus was considered a minor pathogen and was not a priority for maize breeders or pathologists. Aflatoxin was discovered in England in 1961 following an epidemic in poultry. By the early 1970s, surveys of agricultural commodities in the USA found that maize produced in the Southeast was especially vulnerable to aflatoxin contamination. Aflatoxin contamination was initially treated as a post-harvest issue, but pre-harvest contamination was proven by 1975. Pre-harvest contamination meant that genetically based host-plant resistance was a possible solution. The potential magnitude of the problem became apparent in 1977 when the southeastern US maize crop suffered epidemic aflatoxin contamination. The first experiment demonstrating the heritability of host-plant resistance to aflatoxin accumulation was published in 1978. These events combined to make breeding for reduced aflatoxin contamination both a high priority and a rational breeding objective. This review surveys the early scientific literature in order to place research on the genetics of aflatoxin accumulation in maize into historical context. It tells the story of how multi-disciplinary research began with veterinary diseases of unknown etiology and resulted in host-plant resistance to a previously minor plant pathogen becoming a central public sector breeding objective.

Making faces: creating three-dimensional parameterized models of facial expression.

Previous studies of the perceptual processing and dynamics of emotional expression in faces have been limited by the lack of realistic yet controlled stimuli. The present work offers researchers a method for creating such stimuli for exploring these phenomena. We describe the creation of the stimuli and a series of experiments testing the validity of these stimuli with respect to emotional expressions in humans. Participants evaluated synthesized facial images and standardized photographs of six basic emotional expressions for intensity and accuracy of perceived emotion. Comparisons of these measures were qualitatively similar for synthesized and photographed faces. A manipulation of the magnitude of the synthesized expressions yielded a significant effect on the perceived intensity of expression. In a subsequent multidimensional scaling study, no systematic differences were uncovered in the derived configurations of the synthesized expressions and the photographs. These results are discussed in the context of possible future research applications.