Some cetaceans bioaccumulate substantial concentrations of planar halogenated aromatic hydrocarbons (PHAHs) in their tissues, but little is known about the effects of such burdens on cetacean health. 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related PHAHs cause toxicity via activation of the aryl hydrocarbon receptor (AHR), a member of the bHLH-PAS family of transcription factors. Differen...

We consider the question: Does a set of patterns cover all objects of a given type? This is straightforward in the simply-typed setting, but undecidable in the presence of dependent types. We discuss the question in the setting of Beluga, a dependently-typed programming and reasoning environment which supports programming with contextual objects and contexts. We describe the design and implemen...

The effects of in vitro exposure to different organochlorines were evaluated on immune functions of beluga whale peripheral blood leukocytes and splenocytes. The effects of different concentrations of four different congeners of PCBs (138, 153, 180, and 169) as well as two DDT metabolites (p,p'-DDT and p,p'-DDE) were evaluated on phagocytosis and cell proliferation. The effects of dioxins and m...

Toxoplasmosis was diagnosed in two free-ranging beluga whales from the St Lawrence estuary, Quebec, Canada, in 1988 and 1998. Histologically, tachyzoites and bradyzoites were present in the brain, spleen, lymph nodes, adrenals and lungs of both animals, and in the thymus of one. These organisms were readily labelled by an indirect immunohistochemical method for Toxoplasma gondii antigens. In th...

James, Hudson and Ungava bays are summering areas for stocks of beluga whales (Delphinapterus leucas) (Sergeant and Brodie, 1975; Finley et al., 1982; Smith and Hammill, 1986; Richard et al., 1990). There are several apparently separate summer groups, which include a summer group of ~23,000 individuals in western Hudson Bay, a group of 1500 individuals in the eastern Hudson Bay arc, and a few i...

Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near-top trophic-level marine predators have been little studied in polar regions or with latitude. We quantified the large-scale l...

Contaminants described as organochlorines (OCs; e.g., polychlorinated biphenyls [PCBs]) are present in tissues of marine mammals, including beluga whales (Delphinapterus leucas), but the complexity of contaminant exposure often is not fully known. The PCBs, OC pesticides, polybrominated diphenyl ether (PBDE) flame retardants, methylsulfonyl (MeSO2)- and hydroxy (OH)-PCB metabolites, and OH-PBDE...

lactic acid bacteria are characterized as gram-positive, usually non-motile, non-sporulating bacteria that produce lactic acid as a major or sole product of their fermentative metabolism. in this study, the presence of lactobacilli were investigated in the intestines of beluga ( huso huso) and persian sturgeon ( acipenser persicus ), inhabiting caspian sea. the obtained data showed that various...