Showing papers by "Government of Canada published in 1984"

Acidic deposition: Effects on aquatic ecosystems

Abstract: The literature pertaining to the influence of the atmospheric deposition of acidifying substances on aquatic ecosystems is examined in this article. Important chemical species in atmospheric deposition are first identified, and their influence on stream and ultimately on lake water chemistry discussed. Changes that have accompanied acidification among biological communities of decomposers, primary and higher order producers are discussed. Where they exist, hypotheses relating to causes of community changes are examined.

A preliminary investigation on effects of fluctuating flows on invertebrates of the Hawea River, a large regulated river in New Zealand

Abstract: An experiment with flow changing at 3, 9, and 18 m3 s‐1 h‐1 on consecutive days failed to produce any measurable effect on benthic invertebrates in the regulated Hawea River, New Zealand, but did result in increased numbers of drifting chironomid larvae, trichopteran larvae, and oligochaetes compared to days when flow was stable. Drift densities were at least as high on the day flow changed at 3 m3 s‐1 h‐1 (minimum flow 15 m3 s‐1, maximum flow 30 m3 s‐1) as on subsequent days when flow changed at 9 and 18 m3 s‐1 h‐1 (minimum flows both 15 m3 s‐1, maximum flows 60 and 105 m3 s‐1 respectively) indicating that rapid rates of change of flow may not necessarily cause more benthic invertebrates to enter the drift than slow rates of change. Fluctuating flows resulted in more animals entering the drift at a site 5 km below a control dam than at a site 0.8 km below the dam. Drift of non‐invertebrate organic matter (mainly periphyton) showed similar patterns to invertebrate drift. It is suggested that most...

Nonlinear refractive-index phenomena in isotropic media subjected to a dc electric field: Exact solutions

Abstract: An exact, closed-form solution is presented for the propagation characteristics of an intense, arbitrarily polarized optical beam in an isotropic medium which is subjected to a dc electric field. The related phenomena of dc-electric-field-induced optical rectification and second-harmonic generation are examined as well as the propagation characteristics of a weak beam in an isotropic medium in the presence of both the intense optical and dc fields. One fundamental and noteworthy aspect of the results presented here is that both the formalism and the resulting solutions for these third-order nonlinear optical phenomena are given explicitly and entirely in terms of the set of real, observable Stokes parameters rather than in terms of the electric field amplitudes and phases.

Muslims in the Canadian Mosaic

Abstract: (1984). Muslims in the Canadian Mosaic. Institute of Muslim Minority Affairs. Journal: Vol. 5, No. 1, pp. 7-16.

Rapid, sensitive liquid chromatographic method for determination of zearalenone and alpha- and beta-zearalenol in wheat.

Abstract: A rapid, sensitive liquid chromatographic (LC) method is described for quantitative determination of zearalenone and alpha- and beta-zearalenol in wheat. The procedure incorporates an internal standard, zearalenone oxime, to facilitate quantitation and automated analysis. A sample, buffered with pH 7.8 phosphate, is extracted with water-ethanol-chloroform (2 + 50 + 75) and cleaned up. The final residue is dissolved in LC mobile phase and injected onto a reverse phase RP-18 column under the following conditions: water-methanol-acetonitrile (5 + 3 + 2) mobile phase; fluorescence (excitation wavelength 236 nm, 418 nm cut-off emission filter) and UV (254 nm, range 0.0025 AU) detectors. The limit of detectability (twice background) is 0.5 ng for zearalenone and alpha-zearalenol standards on the fluorescence detector and 4 ng for beta-zearalenol on the UV detector, which is equivalent to 20 micrograms zearalenone and 20 micrograms alpha-zearalenol/kg, and 160 micrograms beta-zearalenol/kg feed. Standard curves are linear over the range 0-35 ng zearalenone and alpha-zearalenol on the fluorescence detector and 0-50 ng beta-zearalenol on the UV detector. Recoveries of all compounds are 87.5-101% in the range 0.1-3.0 mg/kg (ppm).

An application of conjoint analysis to leisure research: cultural preferences in Canada.

Abstract: The paper outlines the usefulness of conjoint analysis for studying cultural and leisure preferences. The technique is advantageous because it permits one to make predictions about preferences, by ...

Performance of space-based radar in the presence of earth clutter

Abstract: The paper presents some general principles related to the performance of a space-based radar (SBR) using pulse Doppler to suppress the earth clutter These principles are developed using a heuristic description of clutter as seen from a space-based radar, and illustrated by means of a case study It is demonstrated that SBR performance varies with look direction and that clear areas exist in the clutter spectrum, where targets can be easily detected Also, velocity compensation techniques can be employed to enhance detection for certain look directions

Electrolyte changes of serum and muscle, and related mortalities in maturingAnguilla rostrata migrating down the St. Lawrence Estuary (Canada)

Abstract: This study was made to investigate changes in serum and muscle ion concentrations and related mortalities in maturingAnguilla rostrata migrating down the St. Lawrence Estuary. Mortalities take place in the freshwater portion of the St. Lawrence. Electrolyte concentrations of moribund eels taken in freshwater were compared to those of freshwater and salt water controls. Moribund eels had a much lower serum osmolality (270 mOsm/kg) than the controls (328 and 358 mOsm/kg). This resulted from low sodium (125 mEq/l) and particularly low chloride (69 mEq/l) contents in the moribund eels compared to the freshwater controls (153 and 117 mEq/l) and the salt water controls (179 and 137 mEq/l). There was also a general decrease in muscle ion concentrations in moribund eels though the percentage water was similar to that of the freshwater controls (64.0 and 63.7%). The changes measured between the freshwater controls and the salt water controls in nature are similar to those measured onAnguilla anguilla in laboratory. These results suggest that mortalities are related to failure by some of the maturing eels to maintain their mineral balance in freshwater. Hypothesis is made that maturing eels migrating long distances in freshwater or retarded by physical or chemical barriers, start to excrete sodium and chloride under hormonal control before they have reached brackish water. In the conditions that prevail in the St. Lawrence Estuary, this results in mineral unbalance and possibly in mortalities.

Canadian Broadcasting Policy — A Broad Perspective

Abstract: Mesdames, Messieurs, Je suis heureux de vous saluer et je vous remercie de votre aimable invitation a prendre la parole devant vous au-jourd'hui. Aux specialistes que vous etes, j'apporterai le point de vue a lafois plus modeste et plus englobant du generaliste. — Au depart, cependant, generalisteset specialistes Canadiens partagent avec vous une conviction fondamentale: pour demeurer concurrentiel et conserver sa place dans le peloton de tete des nations les plus industrialisees, le Canada doit necessairement adopter les nouvelles technologies, en particulier celles des communications, susceptibles d'ameliorer la productivite, les couts et l'innovation, tout en favorisant la qualite de la vie. — Dans cette perspective, le gouvernement du Canada, par ses institutions, ses politiques, ses programmes et ses projets et par sa collaboration etroite avec le secteur prive. a ete et demeure activement un des moteurs principaux des progres technologiques realises dans notre pays. Cependant, il ne considere pas le progres technique comme une fin en soi. Sa finalite ne saurait etre uniquement d'ordre economique, elle doit en englober l'impact humain et social. — Au ministere des communications en particulier, nous considerons les technologies nouvelles comme generatrices de progres economiques, certes, mais aussi comme moyens d'atteindre des objectifs sociaux et culturels, ainsi que la loi sur la radio-diffusion l'indique clairement a l'article 3 lorsqu'elle declare: “Que le systeme de la radiodiffusion Canadienne devrait etre possede et controle effectivement par des Canadiens de facon a sauvegarder, enrichir et raffermir la structure culturelle, politique, sociale et economique du Canada.”