The physical appearance of the vulva in ureaplasma infected ewes

The vulvar labia of ewes naturally infected with ureaplasma were significantly more swollen and red than those of uninfected ewes. Similar changes were observed following experimental infection of previously uninfected ewes. These differences, although statistically significant, were not sufficiently marked to be useful in diagnosing infection by clinical examination.     

Current and historical inputs of mercury to high-latitude lakes in Canada and to Hudson Bay

Sediment cores collected from several lakes in northern Canada have been analyzed for mercury and several other chemical contaminants. Sites ranged from the Experimental Lakes Area of northwestern Ontario, north to Cornwallis Island, and west to the southern Yukon. Cores were sliced at sites of collection and individual slices were freeze dried and analyzed for Pb-210 and Cs-137 to estimate average time intervals of deposition. The earliest date estimated by Pb-210 was about 1850, and mercury concentrations in some lakes were clearly increasing before then, assuming no vertical movements of mercury within the sediments. Extrapolation of dates downward to deeper slices, assuming a constant sedimentation rate, indicated that in some lakes mercury inputs increased slowly even in the 1500's, more rapidly after 1750, and more rapidly yet over the current century. These increases are interpreted as increased fluxes of mercury to the lakes as a result of long-range transport of atmospheric mercury, since there are no local industrial sources of mercury. Slices taken near the bottom of a core are taken to estimate the geological component while elevations in excess of that in surface slices are taken to represent contamination from fallout. This partitioning suggests that sediments in the eastern Northwest Territories are dominated by pollution, while those from the western Northwest Territories are influenced more by their geological settings. Two cores from Hudson Bay suggest that mercury is increasing there too, but has not yet exceeded geological sources. Mercury shows little or no tendency to decline in the most recent slices; indicating that inputs of mercury remain at or near their historical maxima. Given relatively high and continuing inputs of mercury to northern lakes it seems likely that some portion of that mercury may find its way into the food chain, hence the long-term prospect is for increasing levels of mercury in northern fish.     

Aromatic polyimides with high melt index modified by 1,6-hexamethylenediamine

1,6-Hexamethylenediamine (HMDA) is utilized to synthesize copolyimides based on bisphenol-A dianhydride and 4,4-oxydianiline or 1,4-bis(4-aminophenoxy) benzene. The purpose of this study is to modify the processability of aromatic polyimides for textile processing and melt property requirements. Polyimides containing an aliphatic HMDA are synthesized via random and block copolymerizations. Variations in the aliphatic content produce a series of polyimides that have different thermal stability, mechanical properties, and processing characteristics. Based on the results, polyimides synthesized with 25 % HMDA have better mechanical properties compared to other contents of HMDA, and block copolyimides have better processability with higher melt index than random copolymers.     

Inflorescence and seed production in festuca pratensis var. apennina (2n\t=28)

Summary Plants of tetraploid Festuca pratensis var. apennina (2n=28) collected from Switserland and Northern Italy produced few inflorescences when grown in the field and under glasshouse conditions. The effects of winter and spring treatments upon reproductive growth were investigated and it was concluded that exposure to low winter temperatures and the control of tiller density in the spring were two important factors controlling the production of inflorescences. A procedure for the production of seed is suggested which will allow breeders to obtain efficient multiplication of collected plant material.