University of Winnipeg

About: University of Winnipeg is a education organization based out in Winnipeg, Manitoba, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 3235 authors who have published 6413 publications receiving 150564 citations. The organization is also known as: U of W.

Factors affecting pheromone production in beetles

Abstract: Pheromone production and/or release by beetles is coordinated with a variety of behavioral, physiological, and environmental factors. To data, two basic mechanisms for the regulation of pheromone biosynthesis in beetles have been proposed. Pheromone biosynthesis may simply be dependent on the availability of biosynthetic precursors. Alternatively, certain stimuli or events may trigger pheromone biosynthesis via juvenile hormone (JH) action. JH may either act directly at the site of pheromone biosynthesis to enhance pheromone production or may act indirectly, through a brain hormone (which might be related to the pheromone biosynthesis activating neuropeptide) or through effects on antennal sensory response. Knowledge of the regulation of the initiation and termination of pheromone biosynthesis is reviewed. Mechanisms by which pheromone stereochemistry is controlled are also discussed. This is an important aspect of pheromone production in Coleoptera, since slight changes in the stereochemistry can completely alter the activity of the molecule. © 1994 Wiley-Liss, Inc.

Crucial role of the postnatal maternal environment in the expression of prenatal stress effects in the male rats.

Abstract: Methodological and conceptual problems common in prenatal stress experiments were analyzed, and an experiment incorporating solutions to those problems were designed and executed. Rats were prenatally stressed or served as controls and then were cross-fostered within or between treatment groups. In adulthood, one male from each litter was tested over 20 trials in an open-field box and then tested over 20 successive discrimination reversals in a T-maze. A T-factor analysis was performed on each of the two sets of observations, and factors scores were subjected to elevational analyses. Major hypotheses generated from the results are the following: (a) Male rats subjected to prenatal stress acquire emotional reactivity levels in adulthood that are either elevated or reduced depending on the postnatal maternal environment. (b) Male rats subjected to prenatal stress acquire reversal learning sets in adulthood with a rapidity that parallels and indeed is produced by the pattern of emotional reactivity reflected in the above a and as mediated by cognitive processes. (c) T-factor analysis of trials is required in order to avoid construct validity problems as well as internal validity problems, both brought about by the confounding of trial variables, and in addition, it may generate valuable hypotheses giving further meaning to the dependent variables under observation.

Unique effective action in five-dimensional Kaluza-Klein theory.

Abstract: The problem of gauge and parametrization dependence in self-consistent dimensional reduction of five-dimensional quantum gravity is discussed. It is shown how the modification of the background-field method suggested by Vilkovisky is crucial for obtaining the correct result. We find that there are no physically acceptable self-consistent solutions of the form ${\mathrm{R}}^{4}$\ifmmode\times\else\texttimes\fi{}${\mathrm{S}}^{1}$ at the one-loop level.