University of Guelph

About: University of Guelph is a education organization based out in Guelph, Ontario, Canada. It is known for research contribution in the topics: Population & Gene. The organization has 26542 authors who have published 50553 publications receiving 1715255 citations. The organization is also known as: U of G & Guelph University.

Absence of natural killer cells during murine pregnancy is associated with reproductive compromise in TgE26 mice

Abstract: Strategies of cell depletion were pursued to extend understanding of the functions of natural killer (NK) cell-like large granulated lymphocytes found in the rodent uterus during pregnancy. Repeated infusions of antibody to Ly-49G2, a surface marker thought to be expressed by the progenitor forms of these cells, removed Ly-49G2+ cells from the virgin but not the pregnant uterus. Large granulated uterine lymphocytes also differentiated during pregnancy in transgenic mice that carried a deletion in the IL-2 gene. This cell population was absent in two strains of mice, p56lck-/lck-.IL-2Rbeta-/IL-2Rbeta- and TgE26. Implantation sites in both of these strains had histopathological anomalies in the zone of decidualization. In TgE26 mice, a sudden onset of fetal loss began at Day 10 of gestation. Fetal death was associated with progressive changes in the maternal uterine arterioles, suggestive of localized arteriosclerosis associated with hypertension. TgE26 females carried immune-competent fetuses to term, apparently through preventive or compensatory mechanisms that may modify the uterine vasculature after the onset of vascular pathology. These studies are the first to suggest a vital role for large granulated lymphocytes in the promotion of fetal survival and pregnancy success.

A knowledge based genetic algorithm for path planning of a mobile robot

Abstract: In this paper, a knowledge based genetic algorithm (GA) for path planning of a mobile robot is proposed, which uses problem-specific genetic algorithms for robot path planning instead of the standard GAs. The proposed knowledge based genetic algorithm incorporates the domain knowledge into its specialized operators, where some also combine a local search technique. The proposed genetic algorithm also features a unique and simple path representation and a simple but effective evaluation method. The knowledge based genetic algorithm is capable of finding an optimal or near-optimal robot path in both complex static and dynamic environments. The effectiveness and efficiency of the proposed genetic algorithm is demonstrated by simulation studies. The irreplaceable role of the specialized genetic operators in the proposed GA for solving robot path planning problem is demonstrated by a comparison study.

Production of somatic and germline chimeras in the chicken by transfer of early blastodermal cells

Abstract: Cells were isolated from stage X embryos of a line of Barred Plymouth Rock chickens (that have black pigment in their feathers due to the recessive allele at the I locus) and injected into the subgerminal cavity of embryos from an inbred line of Dwarf White Leghorns (that have white feathers due to the dominant allele at the I locus). Of 53 Dwarf White Leghorn embryos that were injected with Barred Plymouth Rock blastodermal cells, 6 (11.3%) were phenotypically chimeric with respect to feather colour and one (a male) survived to hatching. The distribution of black feathers in the recipients was variable and not limited to a particular region although, in all but one case, the donor cell lineage was evident in the head. The male somatic chimera was mated to several Barred Plymouth Rock hens to determine the extent to which donor cells had been incorporated into his testes. Of 719 chicks hatched from these matings, 2 were phenotypically Barred Plymouth Rocks demonstrating that cells capable of incorporation into the germline had been transferred. Fingerprints of the blood and sperm DNA from the germline chimera indicated that both of these tissues were different from those of the inbred line of Dwarf White Leghorns. Bands that were present in fingerprints of blood DNA from the chimera and not present in those of the Dwarf White Leghorns were observed in those of the Barred Plymouth Rocks.(ABSTRACT TRUNCATED AT 250 WORDS)

Transitive inference in rats (Rattus norvegicus).

Abstract: Although Piagetian theory proposes that the ability to make transitive inferences is confined to humans above age 7, recent evidence has suggested that this logical ability may be more broad based. In nonverbal tests, transitive inference has been demonstrated in preschool children and 2 species of nonhuman primates. In these experiments, I demonstrate evidence of transitive inference in rats (Rattus norvegicus). I used an ordered series of 5 olfactory stimuli (A E and A > F). The possibility that logical transitivity may reflect a form of spatial paralogic rather than formal deductions from a syllogistic-verbal system is discussed.