Government of Canada

About: Government of Canada is a government organization based out in Ottawa, Ontario, Canada. It is known for research contribution in the topics: Monetary policy & Productivity. The organization has 796 authors who have published 886 publications receiving 21366 citations. The organization is also known as: federal government of Canada & Her Majesty's Government.

Hundreds of Unrecognized Halogenated Contaminants Discovered in Polar Bear Serum.

Abstract: Exposure of polar bears (Ursus maritimus) to persistent organic pollutants was discovered in the 1970s, but recent evidence suggests the presence of unknown toxic chemicals in their blood. Protein and phospholipid depleted serum was stirred with polyethersulfone capillaries to extract a broad range of analytes, and nontarget mass spectrometry with "fragmentation flagging" was used for detection. Hundreds of analytes were discovered belonging to 13 classes, including novel polychlorinated biphenyl (PCB) metabolites and many fluorinated or chlorinated substances not previously detected. All analytes were detected in the oldest (mid-1980s) archived polar bear serum from Hudson Bay and Beaufort Sea, and all fluorinated classes showed increasing trends. A mouse experiment confirmed the novel PCB metabolites, suggesting that these could be widespread in mammals. Historical exposure and toxic risk has been underestimated, and these halogenated contaminants pose uncertain risks to this threatened species.

Morphological and physiological development of olfactory receptor cells in rainbow trout (Salmo gairdneri) embryos.

Abstract: The morphological and functional differentiation of the olfactory receptor cells were investigated in developing rainbow trout (Salmo gairdneri) embryos by means of light and electron (transmission and scanning) microscopy and electrophysiology. Ciliated receptor cells first appeared when the olfactory placode was folded to form a groovelike structure rostrad to the eye at stage 24 (day 18; 18 days postfertilization). Ciliated receptor cells predominated until immature microvillar receptor cells developed in stage 28 (day 26) embryos. At stage 29, the day of hatching, the anterior edge of the olfactory epithelium contained only ciliated receptor cells, and the midregion contained both ciliated and microvillar receptor cells. Spontaneous neural firing activity was recorded from the olfactory mucosa as early as stage 25. The neural responses to amino acids were initially recorded from stage 26 embryos, containing sparse ciliated receptor cells with a few short cilia. The D-enantiomers of amino acids were less effective. From these results we concluded that in rainbow trout the olfactory receptor cell has two separate morphological forms, ciliated and microvillar. These are ontogenetically distinct; the ciliated receptor cells preceded the microvillar. The ciliated receptor cells respond to amino acid stimulation.

Gustatory responses of the rainbow trout (Salmo gairdneri) palate to amino acids and derivatives

Abstract: 1. Gustatory responses to amino acids and derivatives obtained from the palatine nerve (VIIth cranial nerve) of rainbow trout (Salmogairdneri) were studied. 2. The response to an amino acid was characterized by its fast-adapting, phasic nature that returned to baseline within 5 s during continuous stimulation. 3. Complete recovery of the response took place 120 s after stimulation when tested with two identical stimuli given successively (Figs. 2, 3). 4. Among common amino acids tested, onlyL-isomers of proline, hydroxyproline, alanine, leucine, and phenylalanine were stimulatory (Table 1), demonstrating that the facial taste system is more narrowly-tuned to amino acid stimuli than the olfactory system. The arginine derivative,L-α-amino-β-guanidinopropionic acid (L-AGPA) andL-argininic acid, and betaine were also effective. 5. Concentration-response relations, when plotted semi-logarithmically, were generally sigmoidal, saturating at higher concentrations (>1 mM) (Fig. 5). The threshold concentration forL-proline, the most effective amino acid tested, was estimated to be 50 nM. The thresholds for other stimulatory chemicals ranged between 1 and 100 μM. 6. L-AGPA, though having higher threshold (10 μM), could induce responses three times the magnitude of that ofL-proline at 1 mM. 7. The stimulatory activity of heterocyclic-imino acids having 4-, 5-, and 6-membered rings and also of thioproline and hydroxyproline suggests that the receptor recognizes primarily the imino acid region (Fig. 6). 8. Taste responses to amino acids were independent of pH, except that arginine analogues were only active at basic pHs (Fig. 7 and Table 3). larginine was active only at pHs higher than 8.5. The palatal chemoreceptors were stimulated by waters with pHs below 7.0, suggesting the existence of receptors for pH and/or CO2 (Fig. 7).

Continuous passive motion following total knee arthroplasty

Abstract: Background Knee arthroplasty (KA) is a common intervention that can enhance the quality of life for patients with osteoarthritis (OA) and rheumatoid arthritis (RA). Post-surgery rehabilitation protocols often include continuous passive motion (CPM). However, CPM protocols vary considerably amongst institutions. Objectives The purpose of the current meta-analysis is to evaluate the effectiveness of continuous passive motion following total knee arthroplasty. Search strategy An electronic search of MEDLINE (1966 to 2002), EMBASE (1988 to 2002), CINAHL (1982 to 2002), HEALTH STAR (1991 to 1994) and CURRENT CONTENTS (1997 to 2002) was conducted to identify randomized controlled trials. Selection criteria Following an a priori protocol, only randomized controlled trials of CPM for the treatment of participants post KA were eligible. Subjects were 18 years of age or older and had a pre-surgery diagnosis of degenerative joint disease. Both the experimental and control groups received physiotherapy. In addition to the physiotherapy intervention, the experimental group received CPM. Data collection and analysis Two reviewers independently selected trials for inclusion. Data were then extracted and the quality of the trial assessed using predetermined forms. Outcome measures of interest were: active and passive knee range of motion (ROM) length of hospital stay, pain, swelling and quadriceps strength. A fixed effects model was used throughout for continuous variables, except where heterogeneity existed; in which case, a random effects model was used. Results were analyzed as weighted mean differences (WMD) with 95% confidence intervals (CI). Standardized mean differences (SMD) were used when different scales were used to measure the same concept (e.g. pain). Dichotomous outcomes were presented as a relative risk. Main results Fourteen trials were retained for analysis. Results favouring CPM were found for the main comparison of CPM combined with physiotherapy (PT) versus PT alone at end of treatment. For the primary outcomes of interest, CPM combined with PT was found to statistically significantly increase active knee flexion (WMD 4.30 degrees, 95% CI: 1.96, 6.63) and decrease length of stay (WMD -0.69 days, 95% CI: -1.35, -0.03). CPM was also found to decrease the need for post-operative manipulation (RR 0.12, 95% CI: 0.03, 0.53). CPM did not significantly improve passive knee flexion and passive or active knee extension. Authors' conclusions CPM combined with PT, may offer beneficial results compared to PT alone in the short term rehabilitation following total knee arthroplasty.

Bank Leverage Regulation and Macroeconomic Dynamics

Abstract: This paper assesses the merits of countercyclical bank balance sheet regulation for the stabilization of financial and economic cycles and examines its interaction with monetary policy.