新加坡六合彩开奖直播

Moose (Alces alces andersoni) in the Cape Breton Highlands of northern Nova Scotia have exhibited a high incidence of incisorform breakage (macrofracture). Tooth breakage in moose is very rare and has only been previously reported in Alaskan moose (1990) (Alces alces gigas) and in Manitoban moose (1986) (Alces alces andersoni), yet the cause remains uncertain. This study attempted to evaluate the hypothesis of a possible relationship between tooth weakness (leading to breakage) and a nutritional factor related to the unique geology of the Highlands. Fractured (unhealthy) teeth from the Cape Breton Highlands have been compared to unfractured (healthy) teeth from two areas in mainland Nova Scotia; Shelburne and Cumberland Counties. Macrofracture patterns were documented, described, and categorized, while the microfractures were examined using microphotography and electron microprobe imaging. The apatite in tooth enamel and accompanying bony tissue (dentin), were analyzed using Neutron Activation Analysis (NAA), and Electron Microprobe Microanalysis (EPMA). Initial data suggests intriguing geochemical differences between healthy and unhealthy teeth. Preliminary results indicate the macrofractures occur first on the I1 incisor followed by the I2. The microfractures are nearly identical for all degrees of macrofracture, except for two distinct types of dendritic fracture which only occurred in the severely broken teeth. These conclusions were supported by the initial results of the geochemistry analysis, which showed that the unhealthy teeth were comparatively deficient in Zn and Sr, and slightly deficient in Mg and Au. Sr deficiency has been linked to increased incidence of dental caries in human studies.

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Supervisor: Marcos Zentilli