Showing papers by "Government of Canada published in 1982"

Distal symmetric polyneuropathy in the spontaneously diabetic BB-wistar rat. An ultrastructural and teased fiber study.

Abstract: The distal, symmetric polyneuropathy of the spontaneously diabetic BB-Wistar rat was studied ultrastructurally and by means of teased fiber preparations. Ultrastructural findings consisted of malorientation of the axonal cytoskeleton, followed by axonal atrophy, secondary myelin breakdown and distal Wallerian degeneration. This sequence of structural changes could be confirmed by scoring of pathological abnormalities and morphometric evaluation of teased fibers. Distal sensory nerve fibers were affected earlier and more severely than motor fibers.

Dissolved and suspended mercury. species in the Wabigoon River (Ontario, Canada): seasonal and regional variations

Abstract: Seasonal and regional variations in the speciation, sediment-water partitioning, and dynamics of mercury (Hg) were studied at selected sites along the Hg-polluted Wabigoon River, and at unpolluted headwater and tributary sites, during April–September, 1979. ‘Dissolved’ and ‘particulate’ forms of Hg in the water were separated by continuous-flow centrifugation in the field. The Hg and other pollutants such as wood chips and salt had been discharged from a chlor-alkali plant and paper mill at Dryden, Ontario.

Comparison of the uptake and bioconcentration of fluridone and terbutryn by rainbow trout andChironomus tentans in sediment and water systems

Abstract: The rates of uptake and clearance of the aquatic herbicides terbutryn (14C) (2-t-butylamino4-ethylamino-6-methylthio-s-triazine) and (14C) fluridone (1-methyl-3-phenyl-5-(3-trifluoromethylphenyl)-4-(1H)-pyridinone) from water by rainbow trout andChironomus tentans (4th Instar) larvae were determined in static systems. Uptake rates for both herbicides were much lower than those for more hydrophobic compounds tested under similar conditions. Bioconcentration factors (BCFs) for fish of 91 and 312 were estimated for fluridone and terbutryn, respectively, by use of a pharmacokinetic model. Uptake and clearance of fluridone and terbutryn by chironomid larvae were more rapid than for rainbow trout. BCFs for chironomid larvae were estimated to be 128 for fluridone and 48 for terbutryn. Liver, intestine, and pyloric caeca of adult rainbow trout accumulated the highest residues of (14C)-fluridone and -terbutryn. Most of the radioactivity was found to be in the form of fluridone or 4-hydroxyfluridone (1-methyl-3-(4-hydroxyphenyl)-5-(3-trifluoromethyl phenyl)-4(1H)-pyridinone) while terbutryn and de-ethylated terbutryn (2-amino-4-(t-butylamino)-6-(methylthio)-s-triazine) were the major products in tissues of fish exposed to terbutryn. Accumulation of (14C)-fluridone and -terbutryn by chironomid larvae was studied in sediment spiked with 0.5 and 0.05 μg/g of each herbicide. Larvae in contact with sediment accumulated levels of radioactivity of both herbicides that were similar to the levels in larvae held in a screened cup above the sediment.

FET photodetectors: A combined study using optical and electron-beam stimulation

Abstract: The photosensitivity of GaAs FET's has been studied using both optical and electron-beam (e-beam) stimulation at various signal frequencies up to 1.3 GHz. The results indicate that, at high frequencies, the photoconductive mechanism which usually gives a small current gain is the dominant process, whereas at low frequencies photovoltaic mechanisms, which lead to "phototransistor" action are responsible for the observed high photosensitivity and current gain in the device.

Adaptivity Versus Tree Searching in DPCM

Abstract: The interaction is studied between the effects of tree searching and predictor and quantizer adaptation in a differential pulse-code modulation (DPCM) speech digitzer. A 2 s male sentance is digitized at 1 and 2 bits/sample. The maximum entropy method computes a new source model every 8 ms, and a variety of strategiesare used to adapt the quantizer. Results are displayed m plots of local SNR versus time. It is found that the predictor, the quantizer, and the tree search each contribute roughly independently to the total SNR. Adaptivity contributes in total 6-7 dB and tree searching 2-3 dB. Local gains of both types can be higher.

Studies into the effects of cadmium and low pH upon methane production

Abstract: Investigations into the effects of the heavy metal cadmium (Cd) and low pH upon methanogenesis from anaerobic lake sediments were conducted over the period summer 1978 to early spring 1981 at the Freshwater Institute, Winnipeg, and at the Experimental Lakes Area (ELA), north-western Ontario. Experiments conducted at ELA consisted of both laboratory and field studies, while those at the Institute consisted of developmental and test laboratory studies.

Remembering the Monarch

Abstract: The Quee's influence in Canada is waning, as nearly everyone agrees. Yet a majority of Canadians must regret this decline, because opinion polls have shown that for every one Canadian who wants to abolish the monarchy, two want to preserve it. Canadians, it would appear, have resigned themselves to accepting their countr's gradual transformation into a republic, as though it were part of some larger inevitable process. Many of them, for example, continue to support electorally a political party that, since the days of William Lyon Mackenzie King, has had a policy of dissociating Canada from her British imperial past. In 1972, a special joint parliamentary committee formed by the Trudeau government to study the constitution declared that it “preferred a Canadian as Head of State for Canada.”