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1
Devaux, J., C. Beeton, E. Béraud, and M. Crest. "Canaux ioniques et démyélinisation : les fondements d’un traitement de l’encéphalomyélite autoimmune expérimentale (EAE) par des bloqueurs des canaux potassium." Revue Neurologique 160, no. 5 (May 2004): 16–27. http://dx.doi.org/10.1016/s0035-3787(04)71001-2.
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Schaller and Graf. "Zerebrale Ischämietoleranz." Praxis 91, no. 40 (October 1, 2002): 1639–44. http://dx.doi.org/10.1024/0369-8394.91.40.1639.
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La tolérance à l'ischémie se définit comme une réaction cérébrale adaptative rapide à un ou plusieurs épisodes d'ischémie et de reperfusion qui améliorent la tolérance à une ischémie ultérieure de longue durée. Les mécanismes moléculaires de cette tolérance à l'ischémie ne sont connus que de façon partielle. La cascade pathophysiologique peut être décrite comme divisée en induction, transduction et tolérance. Les récepteurs au N-methyl-D-aspartate (NMDA) et à l'adénosine et la conservation de l'énergie métabolique jouent un rôle dans la phase d'induction alors que les protéinases de transduction, les facteurs de transcription et les gènes de réponse immédiate sont actifs dans la phase de transduction. La tolérance est observée dans plusieurs fenêtres temporelles. Une phase précoce est observée quelques heures après le stimulus de préconditionnement et est générée par les récepteurs à l'adénosine et les canaux à potassium ATP dépendants. Cliniquement, il existe des indices que des attaques ischémiques transitoires offrent une protection contre une ischémie cérébrale transitoire ultérieure.
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Valli, P., G. Zucca, and L. Botta. "Perilymphatic potassium changes and potassium homeostasis in isolated semicircular canals of the frog." Journal of Physiology 430, no. 1 (November 1, 1990): 585–94. http://dx.doi.org/10.1113/jphysiol.1990.sp018308.
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Picard, Kelly, Diana Mager, and Caroline Richard. "How Food Processing Impacts Hyperkalemia and Hyperphosphatemia Management in Chronic Kidney Disease." Canadian Journal of Dietetic Practice and Research 81, no. 3 (September 1, 2020): 132–36. http://dx.doi.org/10.3148/cjdpr-2020-003.
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Food processing has a unique impact on patients living with chronic kidney disease who may need to restrict dietary sodium, potassium, and phosphorus intake. Canada is the second largest consumer of processed food in the world. Highly processed foods tend to be more nutrient dense, contain less fibre, and are higher in sodium than unprocessed foods. To reduce the amount of sodium in processed food, Health Canada has encouraged food producers to reduce the sodium in their food. Potassium additives have been identified as an attractive alternative to sodium and their use in food processing is expected to increase. Phosphorus additives have been reported to be present in about 44% of processed foods. Given the changes in the nutrient profiles of processed foods, dietary advice on ways to reduce sodium, potassium, and phosphorus intake may be best achieved by recommending minimally processed food and encouraging unprocessed foods more often.
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Ross, Jessica Zane, and Sidney Omelon. "Canada: Playing catch-up on phosphorus policy." FACETS 3, no. 1 (October 1, 2018): 642–64. http://dx.doi.org/10.1139/facets-2017-0105.
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The concept of sustainable phosphorus is studied in depth around the world, as the scientific community largely agrees that the non-renewable phosphorus reserves in the form of phosphorite ore must be used judiciously. Unfortunately, many developed countries, including Canada, have yet to implement a phosphorus management plan. The Netherlands, Germany, and Switzerland can be heralded as success stories of effective, committed, cross-sector phosphorus management. We examine factors that contributed to their success and consider how these may be transferred to Canada. We also consider Canadian geographic and research factors and contrast the Canadian policy environment and phosphorus recycling efforts with those in the EU. Finally, we analyze active Canadian and North American phosphorus interest groups and seek to determine why their collective efforts have yet to coalesce around tangible action. Canada produces phosphorus fertilizer from imported deposits of phosphate rock. Canada produces potassium fertilizer from its rich potash mines, making it a global power in nutrient production. It is imperative that Canada earns a respected leadership role in efficient global phosphorus and potassium nutrient management and recycling.
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Cowles, Richard S. "Sulfur Amendment of Soil Improves Establishment and Growth of Firs in a Field Naturally Infested with Phytophthora1." Journal of Environmental Horticulture 38, no. 1 (March 1, 2020): 15–21. http://dx.doi.org/10.24266/0738-2898-38.1.15.
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Abstract Acidification of soil from pH 6 to 4 by incorporating elemental sulfur reduced mortality and improved color and initial growth of Fraser fir, Abies fraseri (Pursh) Poir., and Canaan fir, Abies balsamea (L.) Mill. var. phanerolepis Fernald, planted into a field that had previously experienced significant losses consistent with phytophthora root rot. Acidifying the soil improved tree color starting the year of planting and persisting through five years. During their second year after planting, extension of terminal growth was 12.5 vs. 5.6 cm (4.9 vs. 2.2 in) for plots with soil pH of 4 and 6, respectively, averaged across tree species. In subsequent years, the growth rate of trees was unaffected by having acidified the soil. Over the course of five years, the average annual mortality rate for the trees was 1.4, 4.0, 9.7, and 12.2% for Canaan fir (pH 4), Canaan fir (pH 6), Fraser fir (pH 4), and Fraser fir (pH 6), respectively. However, all tree mortality for Canaan fir planted into acidified soil occurred during the first two years. A root dip with potassium phosphite at the time of planting only benefitted Fraser fir. Minimizing losses of trees in this field would require planting species less susceptible or resistant to phytophthora root rot infection and soil acidification. Index words: soil acidification, phytophthora root rot, potassium phosphite, root dip Species used in this study: Fraser fir; Abies fraseri (Pursh) Poir.; Canaan fir; Abies balsamea (L.) Mill. var. phanerolepis Fernald Chemicals used in this study: acibenzolar-S-methyl (Actigard 50WDG); clothianidin (Arena 50WDG); imidacloprid (Xytect 2F); potassium phosphite (Helena Prophyt); sulfur
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Hall, Brian. "Canada East: Liquid potassium fertilizer trial on Ontario soybeans." Crops & Soils 46, no. 3 (May 2013): 10–11. http://dx.doi.org/10.2134/cs2013-46-3-2.
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Wang, Mingyue, and Rui Kong. "STUDY ON THE CHARACTERISTICS OF POTASSIUM SALT INTERNATIONAL TRADE BASED ON COMPLEX NETWORK." Journal of Business Economics and Management 20, no. 5 (August 19, 2019): 1000–1021. http://dx.doi.org/10.3846/jbem.2019.10455.
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This paper studies the evolutionary characteristics of international trade of potassium salts. We construct a weighted and directed complex network model of potassium salt trade, analyze the scale and activity, trade relations, trade flow distribution and the importance of trading countries using UN Comtrade2000-2016 data. Results show that potassium salt trade is more dynamic, resource allocation is more convenient. Some countries have formed trade groups. The relationship between small and major countries is growing. The resource flows of countries with large degrees are conducive to balancing resource’s distribution. Besides Canada is a leading trade country, and the US, the Russian Federation, China and Brazil are trade-led countries. China, the Netherlands, the US, France and India are important hubs. Finally, using Porter's national competitive advantage theory, it proposes countermeasures for forming the international competitive advantage of potassium salt enterprises in different countries.
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Folinsbee, R. E., H. Baadsgaard, and J. Lipson. "POTASSIUM-ARGON DATES OF UPPER CRETACEOUS ASH FALLS, ALBERTA, CANADA*." Annals of the New York Academy of Sciences 91, no. 2 (December 15, 2006): 352–59. http://dx.doi.org/10.1111/j.1749-6632.1961.tb35475.x.
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Perieanu, Mădălina Violeta, Claudia-Camelia Burcea, Viorel Ştefan Perieanu, Mihai Burlibaşa, Gabriela Tănase, Camelia Ionescu, Iuliana Babiuc, et al. "Comparative Study on the Efficiency of Some Common Compounds Used in Controlling Dental Hypersensitivity in Noncarious Cervical Injuries." Acta Medica Transilvanica 25, no. 3 (September 1, 2020): 60–64. http://dx.doi.org/10.2478/amtsb-2020-0053.
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AbstractIn general, the treatment of dentin hyperesthesia can be performed either at home or in the dentist’s office. The therapeutic approach aims at the use of products, which decrease the excitability of pulp nociceptors or reduce the permeability of the dentin canals. The purpose of this study is to compare the efficiency in the treatment of dentin hyperesthesia of a product containing potassium nitrate, compared to another product using Recaldent™ Technology. The results of this study indicated a significant decrease in pain sensitivity both after application of the product using Recaldent™ Technology and after the product containing potassium nitrate, the results being slightly in favour of the first product.
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Martini, Marta, Rita Canella, Alessandro Leparulo, Ivo Prigioni, Riccardo Fesce, and Maria Lisa Rossi. "Ionic currents in hair cells dissociated from frog semicircular canals after preconditioning under microgravity conditions." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 296, no. 5 (May 2009): R1585—R1597. http://dx.doi.org/10.1152/ajpregu.90981.2008.
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The effects of microgravity on the biophysical properties of frog labyrinthine hair cells have been examined by analyzing calcium and potassium currents in isolated cells by the patch-clamp technique. The entire, anesthetized frog was exposed to vector-free gravity in a random positioning machine (RPM) and the functional modification induced on single hair cells, dissected from the crista ampullaris, were subsequently studied in vitro. The major targets of microgravity exposure were the calcium/potassium current system and the kinetic mechanism of the fast transient potassium current, IA. The amplitude of ICa was significantly reduced in microgravity-conditioned cells. The delayed current, IKD (a complex of IKV and IKCa), was drastically reduced, mostly in its IKCa component. Microgravity also affected IKD kinetics by shifting the steady-state inactivation curve toward negative potentials and increasing the sensitivity of inactivation removal to voltage. As concerns the IA, the I- V and steady-state inactivation curves were indistinguishable under normogravity or microgravity conditions; conversely, IA decay systematically displayed a two-exponential time course and longer time constants in microgravity, thus potentially providing a larger K+ charge; furthermore, IA inactivation removal at −70 mV was slowed down. Stimulation in the RPM machine under normogravity conditions resulted in minor effects on IKD and, occasionally, incomplete IA inactivation at −40 mV. Reduced calcium influx and increased K+ repolarizing charge, to variable extents depending on the history of membrane potential, constitute a likely cause for the failure in the afferent mEPSP discharge at the cytoneural junction observed in the intact labyrinth after microgravity conditioning.
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Skitch, Steven A., and Rahim Valani. "Treatment of Pediatric Diabetic Ketoacidosis in Canada: A Review of Treatment Protocols from Canadian Pediatric Emergency Departments." CJEM 17, no. 6 (July 16, 2015): 656–61. http://dx.doi.org/10.1017/cem.2015.56.
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ABSTRACTObjectiveDiabetes is the most common pediatric endocrine disorder, and diabetic ketoacidosis (DKA) is the leading cause of diabetes-related morbidity and mortality. This article reviews pediatric DKA treatment protocols from across Canada and identifies similarities and differences.MethodsPediatric tertiary centres in Canada were asked for a copy of their DKA treatment protocol. For each protocol, we collected information on the amount of initial fluid bolus, maintenance fluid rate, insulin infusion rate, potassium replacement, monitoring and adjustment for serum glucose, administration of bicarbonate, and treatment for cerebral edema.ResultsResponses were obtained from 13 sites. Treatment guidelines were consistent in their recommendations on timing and dosage of intravenous insulin, potassium replacement, monitoring and adjusting for serum glucose, and management of cerebral edema. Variability in treatment protocols was found chiefly in volume of initial fluid bolus (range: 5–20 mL/kg) and length of time boluses should be administered (20–120 min), maintenance fluid rates (based on weight or a 48-hr deficit), and the role of bicarbonate administration.ConclusionsThis is the first review of treatment protocols for pediatric DKA in Canada. It identified many common approaches but noted specific differences in fluid boluses, maintenance fluid rates, and bicarbonate administration. The extent of variation indicates the need for further study, as well as national guidelines that are evidence-based and consistent with best practices.
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Karamanos, Rigas, Norm A. Flore, and John T. Harapiak. "Application of seed-row potash to spring wheat grown on soils with high available potassium levels." Canadian Journal of Plant Science 93, no. 2 (March 2013): 271–77. http://dx.doi.org/10.4141/cjps2012-148.
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Karamanos, R., Flore, N. A. and Harapiak, J. T. 2013. Application of seed-row potash to spring wheat grown on soils with high available potassium levels. Can. J. Plant Sci. 93: 271–277. Two experiments were conducted at numerous locations across western Canada from 1990 to 1994 to ascertain the response of hard red spring (CWRS) wheat (Triticum aestivum L.) to seed-row applied K fertilizers. Soil test K levels at all sites (location×year combinations) exceeded the critical level for western Canada of 125 mg NH4OAc-extractable K kg−1, the concentration below which the probability of a K deficiency is high. In the first experiment, days to maturity and yield for wheat were statistically similar whether or not KCl was applied in the seed row. When the cultivar Roblin was grown significant (P<0.05) yield reductions as a result of seedrow placing low rates of potassium fertilizers were obtained. The second experiment showed that maturity and yield did not respond to treatments including KCl, K2SO4, or CaCl2 fertilizer applied in seed row. Furthermore, spring wheat responses for any of the preceding treatments were not different relative to the control (no K fertilizer applied). These findings bring into question the benefit of seed-row K fertilizer application to hard red spring (CWRS) wheat production on K-sufficient soils in western Canada.
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Quesnel, Pierre-Olivier, and Benoît Côté. "Prevalence of Phosphorus, Potassium, and Calcium Limitations in White Spruce across Canada." Journal of Plant Nutrition 32, no. 8 (July 22, 2009): 1290–305. http://dx.doi.org/10.1080/01904160903006002.
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Raghuwanshi, S. S., B. K. Bhaumik, and S. G. Tewari. "A direct method for determining the altitude variation of the uranium stripping ratio in airborne gamma‐ray surveys." GEOPHYSICS 54, no. 10 (October 1989): 1350–53. http://dx.doi.org/10.1190/1.1442597.
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In airborne gamma‐ray spectrometric surveys, it is essential to calculate the net counts in the thorium, uranium, and potassium channels for quantitative analysis. The net uranium, thorium, and potassium counts are given by [Formula: see text], (1a) [Formula: see text] (1b) and [Formula: see text], (1c) where [Formula: see text], [Formula: see text], and [Formula: see text] are the background corrected counts per second for uranium, thorium, and potassium channels, respectively; α and β are the Compton contributions of thorium gamma rays in the uranium and potassium windows, respectively; and γ is the contribution of uranium gamma rays in the potassium window. In some countries, such as the U.S., Canada, and India, it is common practice to compute the stripping ratios by taking measurements over a set of calibration pads with known and varying amounts of uranium, thorium, and potassium (Grasty and Darnley, 1971; Grasty, 1975; Lovborg, 1984). These factors are determined by keeping the detector system inside the survey aircraft over the calibration pads. The stripping coefficients do not have fixed values but vary with source‐detector distance. Because most airborne surveys are conducted at about 120 m above ground level, the stripping ratios measured over the pads should be corrected for variations with ground clearance. In practice, the ground clearance in airborne gamma‐ray surveys may vary from about 40 m to 200 m depending upon the topography of the area flown. It is, therefore, necessary to know the values of the stripping coefficients as a function of ground clearance at least within the range of investigations. If this is known, it is possible to apply proper corrections while converting all data to a uniform datum of 122 m.
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Rowan, David J., and Joseph B. Rasmussen. "Bioaccumulation of Radiocesium by Fish: the Influence of Physicochemical Factors and Trophic Structure." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 11 (November 1, 1994): 2388–410. http://dx.doi.org/10.1139/f94-240.
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Although many measurements have been made on radiocesium levels in water and aquatic biota, no agreement has been reached regarding the factors affecting bioaccumulation of these radionuclides. With monitoring data from countries that operate nuclear facilities and data from the primary literature, we explored the chemical and ecological factors that determine the bioaccumulation of radiocesium. Using log–linear regression we found that the bioaccumulation of 137Cs by fish was a negative function of both dissolved potassium and suspended sediment concentration, and a positive function of temperature. Important ecological factors were the trophic level of the fish (piscivores bioaccumulate more than plank-tivores and benthivores), and the length of the food chain as reflected by the ratio of piscivore yield relative to net primary production. Fish from softwater drainages, which make up a large portion of northern Europe and Canada, are more vulnerable to radiocesium contamination than fish from hardwater sedimentary drainages, because these waters are extremely low in potassium and suspended sediment, and their watersheds are less efficient in retaining radiocesium. High dissolved potassium, short food chains, and the much greater volume and mixing potential of the ocean make marine fish less vulnerable to releases of radiocesium.
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Dyke, Larry D. "Contaminant migration through the permafrost active layer, Mackenzie Delta area, Northwest Territories, Canada." Polar Record 37, no. 202 (July 2001): 215–28. http://dx.doi.org/10.1017/s0032247400027248.
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AbstractBuried pits (sumps), used for the disposal of drilling muds in the Mackenzie Delta area of Arctic Canada, provide an opportunity for assessing the effectiveness of ice-bonded permafrost sediments as a containment for industrial wastes. Potassium chloride (KCI) added to drilling muds as a freezing-point depressant provides a suitable tracer, because it is easily identified and natural concentrations in sediment pore water are typically low (less than 0.02 g l−1; potassium). Muds with KCI concentrations of up to 10% by weight (100 g l−1) have been used. In the vicinity of sumps, potassium is found at elevated concentrations of up to several g l−1 in the seasonal thaw layer (active layer) at distances well beyond what would be expected from diffusive transport alone. Within the level alluvial silts of the modern Mackenzie Delta, KCI has moved up to 50 m laterally from sump edges. On surrounding tundra uplands, KCI has migrated several hundred metres downslope within the active layer.Although ice-rich permafrost sediments appear to form an effective barrier against downward movement of solutes, thawing ice lenses and veins within the active layer greatly increase the lateral hydraulic conductivity in this zone during the thaw season. Compared with unfrozen silty sediments, the large pores left by thawed ice fabric in the same sediment after a freeze–thaw cycle have been shown to increase the hydraulic conductivity up to four orders of magnitude. This phenomenon is probably common in thawing, ice-rich sediments and presumably favours accelerated downhill movement of solutes. On level ground, it is anticipated that KCI movement is promoted by fluid densities approaching that of sea water. Laboratory experiments with thawed sand and both unfrozen and thawing Mackenzie Delta silt confirm the existence of density-driven solute movement and the importance of thawing ice fabric in promoting solute movement. The thawed ice fabric of active-layer sediments and the presence of a frost table promote lateral movement of fluids when a density or elevation gradient is present. These tendencies widen the area potentially affected by contaminant migration from abandoned waste sites and they may also promote the movement of contaminants that escape from future containments.
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Preston, K. R., and J. E. Dexter. "Canadian short process bread: Potassium bromate response of flour streams and divide flours milled from Canadian red spring wheat." Canadian Journal of Plant Science 74, no. 1 (January 1, 1994): 71–78. http://dx.doi.org/10.4141/cjps94-013.
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Mill streams and divide flours from a pilot-scale milling of commercially grown No. 1 Canada Western Red Spring wheat were baked by a short (no bulk fermentation) baking procedure at various levels of potassium bromate. The quality of bread produced, measured in terms of loaf volume, loaf volume per unit protein and overall bread score showed a wide range of response to potassium bromate level. Household patent flour and the highly refined reduction flours exhibited relatively little baking response to increasing bromate levels, achieving optimum baking performance between 0 and 50 ppm. The least refined reduction flours required higher bromate levels (80–120 ppm) to achieve maximum response, and also demonstrated a greater relative response than the more refined reduction flours. Baker's patent flour and the most refined break flours responded very strongly to bromate, and required higher levels (100–150 ppm) to attain full response. Poorly refined break flours exhibited the highest bromate requirement (225 ppm). Straight-grade flours of 62, 75 and 79% extraction exhibited very little difference in bromate requirements. It appears that stream selection has limited potential as a means of reducing the bromate requirement of bakery flour prepared from Canada Western Red Spring wheat. Key words: Red spring wheat, milling, baking quality, bread, mill streams, bromate response
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Moroni, Martin T., Nelson Thiffault, Brian D. Titus, Christina Mante, and Franz Makeschin. "Controlling Kalmia and reestablishing conifer dominance enhances soil fertility indicators in central Newfoundland, Canada." Canadian Journal of Forest Research 39, no. 7 (July 2009): 1270–79. http://dx.doi.org/10.1139/x09-061.
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Growth rates of young conifers can be poor on disturbed sites dominated by Kalmia angustifolia L. Hence, a conifer revegetation trial was established on a Kalmia -dominated site to evaluate the effects of various silvicultural options and planted species on selected soil organic layer characteristics. Larix laricina (Du Roi) K. Koch, Pinus banksiana Lamb., and Picea mariana (Mill.) BSP seedlings were planted in plots with or without Kalmia control with herbicides. The effect of fertilizer amendment was also assessed. Seventeen years postplanting, organic layer fertility indicators suggest that soil fertility improved after Kalmia control and conifer reestablishment, especially if nitrogen (N) – phosphorus – potassium fertilizer was also applied. When Kalmia was controlled, aerobically mineralizable N and exchangeable sodium concentrations were increased; fertilizer addition to herbicided plots also increased exchangeable potassium and calcium concentrations, and cation exchange capacity compared with untreated control plots. Conifer height, diameter, and canopy closure were Larix > Pinus > Picea. Kalmia cover in control plots was 87%; Kalmia reinvasion in herbicided plots achieved 40%–43% cover but did not differ among the conifer species. Principal component analysis indicated that aerobically mineralizable N and total N were positively correlated with canopy closure. Our results suggest that increases in organic-layer fertility were related to increased conifer size resulting from Kalmia control.
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Harnois, Luc, and Raymond Mineau. "Geochemistry of the Île Cadieux monticellite alnöite, Quebec, Canada." Canadian Journal of Earth Sciences 28, no. 7 (July 1, 1991): 1050–57. http://dx.doi.org/10.1139/e91-095.
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The Île Cadieux alnöite, a small Cretaceous intrusion, is a member of the Monteregian Hills Petrographic Province. Mineral chemistry was determined for olivine, spinel, clinopyroxene, melilite, and a potassium–iron–nickel sulphide akin to djerfisherite. Whole rocks were analysed for major elements and 24 trace elements (including rare-earth elements). The Île Cadieux alnöitic rocks have greater MgO/Al2O3 ratios than most alnöites but are otherwise similar to typical alnöites with respect to major and trace elements. Comparison of spinel and whole-rock chemical compositions from the Île Cadieux and Île Bizard (located 15 km to the northeast) alnöitic intrusions suggests that these magmas were generated under different physicochemical conditions of melting, or alternatively that they are fractions of a single magma which crystallized under different conditions.
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Bérubé, Marc-André, Jacques Locat, Pierre Gélinas, Jean-Yves Chagnon, and Paul Lefrançois. "Black shale heaving at Sainte-Foy, Quebec, Canada." Canadian Journal of Earth Sciences 23, no. 11 (November 1, 1986): 1774–81. http://dx.doi.org/10.1139/e86-163.
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Oxidation of pyrite and crystallization of sulphate minerals in rock fractures have locally produced ground heaving in excess of 10 cm in the foundations of a college at Sainte-Foy, near Québec (Quebec). Black shales of the Sainte-Foy Formation are involved; they contain about 2% disseminated framboidal pyrite and 3% calcite. Reaction products identified with a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray chemical analyser (EDXA) are iron hydroxides and numerous sulphate minerals containing calcium, iron, potassium, aluminum, magnesium, manganese, barium, and strontium. In Ontario, heaving of black shales has been observed in the Ottawa area in particular; rock expansion there was mainly attributed to crystallization of gypsum along the bedding plane cleavages of the shales. At Sainte-Foy, fibroferrite, a fibrous iron–aluminum sulphate mineral, probably also contributed significantly to heaving.
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Toboła, Tomasz, and Piotr Kukiałka. "The Lotsberg Salt Formation in Central Alberta (Canada)—Petrology, Geochemistry, and Fluid Inclusions." Minerals 10, no. 10 (September 30, 2020): 868. http://dx.doi.org/10.3390/min10100868.
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The Lotsberg Salt Formation (LSF) of the Lower Devonian age occupies a large area in Alberta (Canada). It has been used for brine production, disposal, and storage purposes since the 1950s. Its petrological and geochemical features remain poorly understood up to now. Previous studies showed that these salt rocks are large crystalline and distinguishable by a very low bromine content (2–5 ppm). Our studies reveal that the main impurity is dolomite with an addition of haematite. It showed, also, a lack of sulphate minerals (anhydrite). Manganite also occurs within the halite crystals. Microthermometric measurements of primary fluid inclusions in halite show a large range of homogenization temperatures from 32.4 °C to 357.0 °C with the highest temperature in the upper part of the salt profile. Geochemical analysis confirms the low bromine contents, which is between 0.67–12.74 ppm. Potassium contents (166–3651 ppm) seem to be in the normal range for salt rocks, but magnesium content (25–177 ppm) is much lower than potassium. Rubidium is, as well, within the normal range, with values between <0.01 ppm and 3.13 ppm, while caesium contents (5.07–211.22 ppm) are almost sixty times higher in comparison to those of rubidium. The high concentration of Cs, Mn, Rb, and the high homogenization temperatures of the host minerals suggest that the LSF underwent extensive ion exchange related to hydrothermal inflow. These hydrothermal solutions originated from the basement of the LSF.
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Sanderson, Kevin R., and J. Brian Sanderson. "Potassium management for carrots in Prince Edward Island." Canadian Journal of Plant Science 86, Special Issue (December 1, 2006): 1405–7. http://dx.doi.org/10.4141/p06-108.
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Nine field studies were conducted over a 3-yr period to determine the response of carrot (Daucus carota L.) to soilapplied K on sandy to loamy sand Orthic Podzol soils in Prince Edward Island (PEI), Canada. Mid-season soil K levels ranged from 34 to 103 µg g-1, and sites were classified as L– (very low), L (low) and M (medium) (Mehlich 3 extractable) according to the PEI Soil and Feed Testing Laboratory. Cultivars used were Imperator-type and the crops were managed to conform to local growing practices. Treatments consisted of preplant broadcast applied muriate of potash (KCl) at 0, 75, 150, 225 or 300 kg K ha-1. When no K was applied, total carrot yields on the L–, L and M soil K ratings were 70, 90 and 98% of the maximum yield, respectively. To achieve 95% of the maximum yield, 150, 75 and 0 kg K ha-1 were required on the L–, L and M soils, respectively. Increasing rates of applied K linearly increased the K content of carrot petioles and soil samples taken at harvest. Potassium content in the carrot roots increased linearly with the rate of applied K, but parallel line analyses indicated that separate K response lines were required for each K soil test rating. Rates of 300, 150 and 75 kg K ha-1 were required to increase root K content to above the published standard of 27 mg g-1 (DM basis) on the L–, L, and M soil K sites, respectively. Key words: Carrot, potassium, soil K rating, nutrient content, yield
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Murphy, Mary M., Leila M. Barraj, Tristin D. Brisbois, and Alison M. Duncan. "Frequency of fruit juice consumption and association with nutrient intakes among Canadians." Nutrition and Health 26, no. 4 (August 12, 2020): 277–83. http://dx.doi.org/10.1177/0260106020944299.
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Background: In Canada, studies on consumption of 100% fruit juice and nutrient intakes are limited. Aim: This study aimed to evaluate nutrient intakes and adequacy of intake by frequency of fruit juice consumption. Methods: Individuals ≥1 year ( n = 34,351) participating in the Canadian Community Health Survey, 2004 with a 24-hour dietary recall and reported usual frequency of fruit juice consumption (assumed to be 100% juice) were categorized by frequency of consumption as <0.5, ≥0.5 to <1.5, or ≥1.5 times/day. Results: More frequent consumption of fruit juice (≥0.5 times/day) was associated with higher intakes of total fruits and vegetables, whole fruits, energy, total sugars, vitamin C and potassium. More frequent consumption of fruit juice was associated with improved intake adequacy of vitamin C for adults. Conclusions: Fruit juice consumption contributes to increased intakes of vitamin C and potassium as well as energy and total sugars, thus presenting a trade-off for consumers to balance.
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Boehnke, Patrick, Elizabeth A. Bell, Thomas Stephan, Reto Trappitsch, C. Brenhin Keller, Olivia S. Pardo, Andrew M. Davis, T. Mark Harrison, and Michael J. Pellin. "Potassic, high-silica Hadean crust." Proceedings of the National Academy of Sciences 115, no. 25 (June 4, 2018): 6353–56. http://dx.doi.org/10.1073/pnas.1720880115.
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Understanding Hadean (>4 Ga) Earth requires knowledge of its crust. The composition of the crust and volatiles migrating through it directly influence the makeup of the atmosphere, the composition of seawater, and nutrient availability. Despite its importance, there is little known and less agreed upon regarding the nature of the Hadean crust. By analyzing the 87Sr/86Sr ratio of apatite inclusions in Archean zircons from Nuvvuagittuq, Canada, we show that its protolith had formed a high (>1) Rb/Sr ratio reservoir by at least 4.2 Ga. This result implies that the early crust had a broad range of igneous rocks, extending from mafic to highly silicic compositions.
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Simons, R. G., C. A. Grant, and L. D. Bailey. "Effect of fertilizer placement on yield of established alfalfa stands." Canadian Journal of Plant Science 75, no. 4 (October 1, 1995): 883–87. http://dx.doi.org/10.4141/cjps95-146.
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Alfalfa yield response to P and K fertilization management has been documented elsewhere, but little work has been done in western Canada. Field studies conducted on two Manitoba soils for 4 yr evaluated the effects of four levels of monoammonium phosphate and three levels of potassium chloride fertilizers, applied as a surface broadcast or as an in-soil band application, on the yield of established alfalfa (Medicago sativa L.) stands. Applied P increased total annual forage yield on the clay loam soil by 1.53 t h−1 (47%), when averaged over the 4 yr of the study, but did not increase yields on the fine sandy loam. Yield response to P application on the clay loam soil increased over the 4 yr of the study. Potassium application resulted in minor or no increases in forage yield on both soils. On the clay loam soil, there was no yield difference between banded and broadcast fertilizer applications. On the fine sandy loam soil, band application reduced yields slightly compared with broadcast application, particularly at the first harvest following fertilizer application. Grass ingress into the plots was reduced by K application but was not affected by P fertilization, which may indicate a beneficial effect of K fertilization on alfalfa vigor and persistence. Key words: Potassium, phosphorus, banding, broadcast, persistence
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Haag, M. D. M., J. R. Kelly, A. Ho, and D. W. Seccombe. "A study to examine the accuracy of potassium measurements in clinical laboratories across Canada." Clinical Biochemistry 33, no. 3 (April 2000): 229. http://dx.doi.org/10.1016/s0009-9120(00)00096-5.
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Haag, Mendel D. M., Joseph R. Kelly, Amy Ho, and David W. Seccombe. "A study to examine the accuracy of potassium measurements in clinical laboratories across Canada." Clinical Biochemistry 33, no. 6 (August 2000): 449–56. http://dx.doi.org/10.1016/s0009-9120(00)00150-8.
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Sharifi, Mehdi, Mumtaz Cheema, Kristie McVicar, Lise LeBlanc, and Sherry Fillmore. "Evaluation of liming properties and potassium bioavailability of three Atlantic Canada wood ash sources." Canadian Journal of Plant Science 93, no. 6 (November 2013): 1209–16. http://dx.doi.org/10.4141/cjps2013-168.
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Sharifi, M., Cheema, M., Mahoney, K., LeBlanc, L. and Fillmore, S. 2013. Evaluation of liming properties and potassium bioavailability of three Atlantic Canada wood ash sources. Can. J. Plant Sci. 93: 1209–1216. Wood ash has the potential to enhance productivity in agricultural systems by influencing soil pH and nutrient availability. The liming properties and fertility values of wood ash from three Atlantic wood ash sources were evaluated in this study. The liming properties were tested using three wood ash sources [JD Irving (IR), New Page (NP), and Brooklyn Power (BP)] and two local lime sources in an 8-mo incubation experiment at 25°C. Soil pH was measured 14 times during the incubation. Availability of potassium (K) in wood ash was evaluated in a greenhouse setting with a K-deficient soil using annual ryegrass as the test plant. Total plant K and P uptake and Mehlich-3 extractable K and P were used as predictors of nutrient bioavailability. Wood ash application increased soil pH to the maximum level within the first 50 d after application and stabilized soil pH for 8 mo. The measured effective calcium carbonate equivalent of ashes relative to Mosher lime average among two soils were in order of BP (32)>IR (25)>NP (16). About 96, 38, and 71% of total K in IR, NP and BP ash sources, respectively, were bioavailable for ryegrass in 115 d. Although soil was not P deficient, soil P bioavailability (Mehlich III extractable P) was enhanced by 14 and 48% in NP and BP wood ash treatments, respectively, whereas P bioavailability decreased by 24% in the IR ash treatment. The results clearly demonstrate that these sources of wood ash can be considered as an effective liming agent and source of K in agricultural production systems.
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Huber, Franziska, and Fernanda Helena dos Reis. "Técnica Alternativa para Montagem de Insetos em Lâminas Permanentes para Visualização em Microscopia Óptica." EntomoBrasilis 4, no. 1 (March 31, 2011): 13–19. http://dx.doi.org/10.12741/ebrasilis.v4i1.112.
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Diversas substâncias químicas são utilizadas na montagem de insetos em lâminas permanentes para visualização em microscopia óptica. O alto custo, a indisponibilidade no comércio convencional e a periculosidade de tais substâncias químicas, fazem com que este meio de estudo prático torne-se pouco viável para alguns estudos didáticos. Dentre os diversos produtos químicos utilizados para a montagem de insetos em lâminas permanentes os mais utilizados são o xilol, bálsamo do Canadá, hidróxido de potássio, alcoóis, fenol, creosoto, entre outros. Todos estes produtos químicos apresentam, individualmente ou em conjunto, alguns riscos para a saúde humana. Com a finalidade de encontrar materiais alternativos, de fácil acesso e baixa toxicidade para a montagem de insetos em lâminas permanentes para microscopia, o presente estudo testou a eficiência de algumas substâncias alternativas. Foram testados: verniz vitral incolor (Acrilex®) como substituto do bálsamo do Canadá e solvente para artesanato (Acrilex®), Óleo de imersão (Merck®) e xilol em substituição ao creosoto de Faia. Foram realizadas montagens de Ctenocephalides sp., de Aedes aegypti (Linnaeus) e Pediculus sp.. O uso de verniz vitral incolor mostrou ser um substituto barato e eficiente ao Bálsamo do Canadá, oferecendo ótima transparência e visualização, além de rápida secagem. O óleo de imersão pôde ser utilizado em substituição ao creosoto de Faia, tanto para montagens em bálsamo, quanto em verniz, sendo que a última combinação apresentou vantagens, devido à rapidez da secagem do verniz. O solvente para artesanato não obteve bons resultados aparentando agredir demasiadamente a quitina dos insetos, efeito observado principalmente quando em combinação com o verniz vitral.
Alternative Permanent Slide Mounting Technique of Insects for Light Microscopy
Abstract. Various chemicals are used in the mounting of insects on permanent slides for optical microscopy. The high cost, little availability in ordinary commerce and the dangers make their use impractical for some studies. Among the various chemicals used for the microscopic mounting of insects are Xylene, Canada Balsam, Hydroxide Potassium, Alcohols, Phenol and Creosote. All these chemicals present, individually or collectively, some risks to human health. In order to find alternative materials of easy access and low toxicity, for the permanent mout of insects, this study tested the efficacy of some alternatives materials. Were tested: Colorless varnish (Acrilex ®) as a substitute for Canada balsam and solvent (Acrilex ®), Immersion Oil for microscopy (Merck ®) and Xylene as substitutes for creosote. There were mounted especimens of Ctenocephalides sp., Aedes aegypti (Linnaeus) and Pediculus sp.. The use of Varnish Colorless proved to be an efficient and cheap substitute to Canada Balsam because it offered transparency, optimal visualization, and rapid drying. The immersion oil might be used instead of Creosote, both mounted in Balsam, as in varnish. The last combination was more advantageous due to rapid drying of the varnish. Solvent did not get good results appearing to damage insect chitin, an effect observed especially when combined with the varnish.
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Ryswyk, A. L. van, D. G. Stout, B. H. Roddan, E. J. Hogue, and J. W. Hall. "Soil properties associated with alfalfa winter survival at Kamloops, British Columbia." Canadian Journal of Soil Science 73, no. 1 (February 1, 1993): 141–46. http://dx.doi.org/10.4141/cjss93-016.
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Alfalfa (Medicago sativa L.) survival at Kamloops Agriculture Canada Research Station decreased following the 1985–1986 cold event, when survival varied along a soil gradient. Survival was positively related to the soil's potential available soil-water storage capacity, which may have contributed to a temporary buffering of soil-temperature decline. However, this relationship was not observed following the 1988–1989 cold event, when the air-temperature drop was greater following a prolonged mild period. Key words: Medicago sativa, low-temperature injury, cold hardiness, available water storage capacity, extractable soil potassium
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Comeau, Paul L., and David J. Bellamy. "An ecological interpretation of the chemistry of mire waters from selected sites in eastern Canada." Canadian Journal of Botany 64, no. 11 (November 1, 1986): 2576–81. http://dx.doi.org/10.1139/b86-340.
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Water samples (132) were collected from selected mires in eastern Canada. Sites chosen included ombrotrophic, transition, and minerotrophic mire in both maritime and continental areas in Nova Scotia, New Brunswick, and Quebec. Chemical analysis of the major ions found in mire waters revealed that concentrations increased from ombrotrophic to minerotrophic conditions. Chloride, sodium, and magnesium were more abundant in maritime mires, while calcium, potassium, and sulfate had higher levels in transition and ombrotrophic mire in agricultural areas. Comparison with studies in Europe indicates similar ionic conditions for the three mire categories with respect to proximity to the sea and human disturbance.
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Molander, A., C. Reit, and G. Dahlén. "The antimicrobial effect of calcium hydroxide in root canals pretreated with 5% iodine potassium iodide." Dental Traumatology 15, no. 5 (October 1999): 205–9. http://dx.doi.org/10.1111/j.1600-9657.1999.tb00775.x.
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Ryan, A. B., W. R. A. Baragar, and D. J. Kontak. "Geochemistry, Tectonic Setting, and Mineralization of High-Potassium Middle Proterozoic Rocks in Central Labrador, Canada." Geological Society, London, Special Publications 33, no. 1 (1987): 241–54. http://dx.doi.org/10.1144/gsl.sp.1987.033.01.17.
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Schuerger, Andrew C., and William Hammer. "Suppression of Powdery Mildew on Greenhouse-Grown Cucumber by Addition of Silicon to Hydroponic Nutrient Solution Is Inhibited at High Temperature." Plant Disease 87, no. 2 (February 2003): 177–85. http://dx.doi.org/10.1094/pdis.2003.87.2.177.
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Silicon amendments to hydroponic nutrient solutions have been used successfully in Canada to suppress powdery mildew (PM) caused by Sphaerotheca fuliginea on cucumber (Cucumis sativus). In contrast, preliminary trials in Florida greenhouses failed to achieve the level of disease suppression reported in the literature for Canadian studies. A series of greenhouse experiments were conducted in Florida to determine the factors involved in reducing the effectiveness of silicon amendments for PM suppression on cucumber. Three horticultural practices (cultivar, nutrient solution formula, and rooting medium) and two environmental factors (light intensity and temperature) were tested in combination with silicon amendments for their effects on the suppression of PM on cucumber. When plants were irrigated with a standard nutrient solution amended with potassium silicate at 0 mg/liter, the cucumber cv. Vetomil was found to be resistant and cvs. Corona, Cilla, Farbio, and Toska were found to be susceptible to PM. Susceptible cultivars irrigated with potassium silicate at 100, 150, or 200 mg/liter exhibited a slight but statistically significant reduction in PM over the course of a 49-day trial. Although PM in the cultivar trial was slightly lower in treatments with added silicon, disease suppression with silicon was not commercially useful because it failed to increase fruit yields. Nutrient solution formula, rooting medium, and light intensity had no effects on the levels of PM suppression, regardless of whether plants were irrigated with potassium silicate at 0 or 100 mg/liter. Temperature was found to act in a synergistic manner with silicon. The greatest effect of temperature on PM suppression was observed at 20°C in which cucumber plants, irrigated with silicon at 100 mg/liter, exhibited significant reductions in the numbers of PM colonies per leaf. Disease suppression by silicon was observed at 25 and 30°C, but the magnitude of the disease suppression was significantly lower than when plants were maintained at 20°C. The effect of temperature on PM suppression by silicon may explain the difference in results between previous experiments in Canada, where greenhouse temperatures averaged 20 to 25°C, and the current study in Florida, where greenhouse temperatures averaged 24 to 32°C.
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Rennie, K. J., and M. J. Correia. "Potassium currents in mammalian and avian isolated type I semicircular canal hair cells." Journal of Neurophysiology 71, no. 1 (January 1, 1994): 317–29. http://dx.doi.org/10.1152/jn.1994.71.1.317.
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1. Type I vestibular hair cells were isolated from the cristae ampullares of the semicircular canals of the Mongolian gerbil (Meriones unguiculatus) and the white king pigeon (Columba livia). Dissociated type I cells were distinguished from type II hair cells by their neck to plate ratio (NPR) and their characteristic amphora shape. 2. The membrane properties of gerbil and pigeon type I hair cells were studied in whole-cell voltage- and current-clamp using the perforated patch technique with amphotericin B as the perforating agent. 3. In whole-cell current-clamp, the average zero-current potential, Vz, measured for pigeon type I hair cells, was -70 +/- 7 (SD) mV (n = 18) and -71 +/- 11 mV (n = 83) for gerbil type I hair cells. 4. At Vz, for both gerbil and pigeon type I hair cells, a potassium current (IKI) was > or = 50% activated. This current deactivated rapidly when the membrane potential was hyperpolarized below -90 mV. 5. IKI was blocked by externally applied 4-aminopyridine (4-AP) (5 mM) and by internally applied 20 mM tetraethylammonium (TEA). It was also reduced when 4 mM barium was present in the external solution. The degree of block by barium increased as the membrane potential became more positive. External cesium (5 mM) blocked the inward component of IKI. When IKI was pharmacologically blocked, Vz depolarized by approximately 40 mV. Therefore IKI appears to be a delayed rectifier and to set the more negative Vz noted for isolated type I hair cells when compared to isolated type II hair cells, which do not have IKI. 6. A second, smaller potassium current was present at membrane potential depolarizations above -40 mV. This current was blocked by 30-50 mM, externally applied TEA, 100 microM quinidine, 100 nM apamin, but not 100 nM charybdotoxin, indicating that this is a calcium-activated potassium current, IK(Ca), different from the maxi-K calcium-activated potassium current found in most other hair cells.
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Hosseini, Seyed H., Yanni Papanikolaou, Naorin Islam, Patil Rashmi, Arash Shamloo, and Hassan Vatanparast. "Consumption Patterns of Grain-Based Foods among Adults in Canada: Evidence from Canadian Community Health Survey—Nutrition 2015." Nutrients 11, no. 4 (April 4, 2019): 784. http://dx.doi.org/10.3390/nu11040784.
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In this study, we used the Canadian Community Health Survey-Nutrition (CCHS) 2015 data to examine the consumption patterns of grain-based foods (GBFs) for Canadian adults. We used a k-mean cluster analysis based on the contribution of 21 grain-based foods to total energy intake of adults in Canada to find the dietary patterns of GBFs. Cluster analyses rendered seven dietary patterns including: ‘other bread’, ‘cake and cookies’, ‘pasta’, ‘rice’, ‘mixed’, ‘white bread’, and finally ‘whole wheat and whole-grain bread’. ‘No grain’ and ‘rice’ consumers had lower intakes of dietary fibre, folate, iron and calcium, which are the nutrients of public health concern in Canada. Adults consuming a ‘mixed grain’ dietary pattern had a greater daily intake of calcium, potassium, magnesium, riboflavin, and vitamin B6 than those in the ‘no grain’ dietary pattern. We also observed that a considerable proportion of individuals clustered in the ‘rice’ group are immigrants and belong to households with lower income levels.
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Verma, P. R. "Biology and control of Rhizoctonia solani on rapeseed : A Review." Article de synthèse 77, no. 3 (April 12, 2005): 99–111. http://dx.doi.org/10.7202/706106ar.
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Rhizoctonia solani AG2-1 is the principal pathogen causing damping-off and seedling and mature plant root rot (brown girdling root rot) in oilseed rape and canola (Brassica napus and B. rapa) in western Canada and the United States; AG4 isolates mainly attack adult plants and cause basai stem rot. Seedling infection by AG2-1 is favoured by cool weather atthe time of planting, whereas warm weather late in the growing season is more conducive for infection of mature plants by AG4 isolates. Survey data show that disease development is favoured by high soil moisture, low levels of nitrogen, phosphorus and potassium and high levels of copper in fine-textured soils. Moderate resistance in condiment mustard (Sinapis alba) and some other species appears to be genetically controlled and should be utilised in breeding programmes. Carboxin and iprodione in mixtures with insecticide gamma-HCH are recommended in Canada as seed treatments to control damping-off and seedling root rot, but do not control brown girdling root rot.
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Thomas, Ben W., Derek Hunt, Shabtai Bittman, Kirsten D. Hannam, Aimé J. Messiga, Dennis Haak, Mehdi Sharifi, and Xiying Hao. "Soil health indicators after 21 yr of no-tillage in south coastal British Columbia." Canadian Journal of Soil Science 99, no. 2 (June 1, 2019): 222–25. http://dx.doi.org/10.1139/cjss-2018-0146.
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The lower Fraser Valley is one of the most intensively cropped regions in Canada. Yet, how soil health indicators respond to long-term intensive agricultural management is poorly documented in this region. Thus, we evaluated a suite of soil health indicators in response to 21 growing seasons of continuous silage corn (Zea mays L.) under conventional tillage or no-tillage (0–20 cm soil layer). Wet aggregate stability, available water capacity, active carbon (permanganate oxidizable, POXC), and extractable potassium and extractable magnesium were significantly greater with no-till than conventional tillage, whereas 8 of 13 indicators were similar. Soil health indicators responded more favourably to no-till than conventional tillage.
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Hogarth, D. D. "FLUORO-POTASSIC-MAGNESIO-ARFVEDSONITE, KNa2Mg5Si8O22F2, FROM THE OUTAOUAIS REGION, QUEBEC, CANADA." Canadian Mineralogist 44, no. 1 (February 1, 2006): 289. http://dx.doi.org/10.2113/gscanmin.44.1.289.
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McKeown, Alan, and Cathy Bakker. "543 Effect of Calcium and Sulfur on Yield of Late-storage Cabbage." HortScience 35, no. 3 (June 2000): 489B—489. http://dx.doi.org/10.21273/hortsci.35.3.489b.
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Soil and crop management practices suggest the possibility of sulfur deficiency for cole crops in Southern Ontario. A 3-year study was conducted to evaluate rates of calcium and sulfur on yield of `Huron' late-storage cabbage. Treatments were based on CaSO4 applied at 0, 1000, 2000, and 3000 kg·ha–1 `Novacal' (Ca 27%, S 19%, Mg 2.5%, Dolomex Inc., Portage-du-Fort, Quebec, Canada), a granulated gypsum product. Potassium sulfate and calcium nitrate were used as elemental controls. Potassium and nitrogen levels were balanced with potassium chloride and ammonium nitrate. Phosphorous applications were based on soil analysis. All treatments were applied pre-plant incorporated. This trial was repeated on sand and loam soils typical of soil used for cabbage production in southern Ontario. Applications of sulfur increased yield of cabbage on sand and clay, although the optimum rate varied from year to year. Medium and high rates produced the highest yield in the first year, while low rates were more effective in the second and third seasons. Response of cabbage to calcium varied from year to year. Medium and high rates of calcium increased yield on sand, but had no effect on clay in the first year. Calcium had no effect on yield on either soil type in the second year. However, in the third year, low rates of calcium produced the highest yield on both sand and clay. Although there were no visual symptoms of deficiency, applications of sulfur, and to a lesser extent calcium, increased yield indicating that a `hidden hunger' for these elements may exist on some soils in southern Ontario.
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Mitchell, R. H., M. D. Welch, A. R. Kampf, A. K. Chakhmouradian, and J. Spratt. "Barrydawsonite-(Y), Na1.5CaY0.5Si3O9H: a new pyroxenoid of the pectolite–serandite group." Mineralogical Magazine 79, no. 3 (June 2015): 671–86. http://dx.doi.org/10.1180/minmag.2015.079.3.12.
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AbstractThe new pyroxenoid barrydawsonite-(Y) occurs at the Merlot Claim, North Red Wine Pluton, Labrador, Canada (62°32'38.54'' W; 54°08'1.37'' N). The host rock is a metamorphosed eudialyte syenite consisting of eudialyte, potassic arfvedsonite, jadeitic aegirine, nepheline, albite and potassium feldspar with accessory Y-bearing pectolite, britholite and steenstrupine. Barrydawsonite-(Y) crystals commonly have discrete thin rims of Y-bearing pectolite. The average empirical formula (based on nine anions p.f.u.) is Na1.54Ca0.74Mn0.15Fe0.07Y0.38Nd0.01Sm0.01Gd0.02Tb0.01Dy0.04Ho0.01Er0.02Yb0.01Si3.00O9H. The simplified formula is Na1.5Y0.5CaSi3O9H. Barrydawsonite-(Y) is related to pectolite by the substitution ½[NaM3+Ca–2] (M3+ = Y,REE), and is exceptional in being the only member of the pectolite group that has the structure of the monoclinic M2abc polytype. The crystal structure has been determined in monoclinic space group P21/a: a = 15.5026(2), b = 7.0233(1), c = 6.9769(1) Å, β = 95.149(1)°, V = 756.58(2) Å3(Z = 4). Final agreement indices are R1 = 0.038, wR2 = 0.068, Goof = 1.136. The asymmetric unit of barrydawsonite-(Y) has three metal sites: M(1) = Ca, M(2) = Na0.5(Y,REE)0.5, M(3) = Na. M(1) and M(2) are octahedrally-coordinated sites, whereas M(3) is [8]-coordinated as in pectolite and serandite. The structural formula for the empirical composition is M(3)Na1.00M(2)(Na0.50Y0.38REE0.13)Σ=1.01M(1)(Na0.04Ca0.74Mn0.152+Fe0.072+)Σ=1.00Si3O9H. There is excellent agreement between the refined site-scattering values and those calculated based upon the structural formula.Barrydawsonite-(Y) is biaxial (+) with α = 1.612(1), β = 1.617(1), γ = 1.630(1) (white light) and 2V = 63(1)°. The five strongest peaks in the X-ray powder diffraction pattern are [dobs (Å), Iobs%, (hkl)]: [2.905, 100, (023)], [3.094, 30, (210,211,121,202)], [1.7613, 29, (127,323,040)], [3.272, 27, (202,104)], [1.7016, 27, (140,227,325)].
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Lafond, J., and D. Pageau. "Fertilisation phosphatée et potassique dans la culture du pois sec." Canadian Journal of Plant Science 90, no. 5 (September 1, 2010): 629–36. http://dx.doi.org/10.4141/cjps09152.
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In Quebec, the P recommendations for dry peas (Pisum sativum L.) are nearly three times higher than those in western Canada, while recommendations for K are at least 20% lower. The objective of this project was to re-evaluate the P and K needs of dry peas under the climatic conditions of the Saguenay-Lac-Saint-Jean region (Quebec, Canada) in soils with a range of soil P and K availabilities. The treatments consisted of four P rates (0, 20, 40, 80 and 160 kg P2O5 ha–1) and three K rates (0, 50 and 150 kg K2O ha–1). The trials were conducted at two sites over 3 yr. Site 1 was classified as low in P availability and site 2 as medium according to the soil analysis. Both sites had a medium level of soil K availability. Grain yields increased significantly, by 6%, with increasing fertilizer P (3246 to 3437 kg ha–1). Potassium fertilization had no significant effect on grain yields. Grain yields were also 37% higher in the highest soil P site. This low response of the crop to mineral fertilizers was attributed to the significant soil contribution to crop P and K needs. Soil tests have also indicated an enrichment of P and K with large inputs of mineral fertilizers. Thus, a rate of 30-35 kg P2O5 ha–1 for P poor soils would be sufficient to meet the crop needs. For soils with moderate levels of K (201-400 kg K ha–1), a rate of 50 kg K2O ha–1 would be sufficient to meet the crop needs and to maintain the soil fertility. Key words: Enrichment, efficiency, phosphorus, potassium, Pisum sativum L.
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Legrand, Michel, Joseph McConnell, Hubertus Fischer, Eric W. Wolff, Susanne Preunkert, Monica Arienzo, Nathan Chellman, et al. "Boreal fire records in Northern Hemisphere ice cores: a review." Climate of the Past 12, no. 10 (October 28, 2016): 2033–59. http://dx.doi.org/10.5194/cp-12-2033-2016.
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Abstract. Here, we review different attempts made since the early 1990s to reconstruct past forest fire activity using chemical signals recorded in ice cores extracted from the Greenland ice sheet and a few mid-northern latitude, high-elevation glaciers. We first examined the quality of various inorganic (ammonium, nitrate, potassium) and organic (black carbon, various organic carbon compounds including levoglucosan and numerous carboxylic acids) species proposed as fire proxies in ice, particularly in Greenland. We discuss limitations in their use during recent vs. pre-industrial times, atmospheric lifetimes, and the relative importance of other non-biomass-burning sources. Different high-resolution records from several Greenland drill sites and covering various timescales, including the last century and Holocene, are discussed. We explore the extent to which atmospheric transport can modulate the record of boreal fires from Canada as recorded in Greenland ice. Ammonium, organic fractions (black and organic carbon), and specific organic compounds such as formate and vanillic acid are found to be good proxies for tracing past boreal fires in Greenland ice. We show that use of other species – potassium, nitrate, and carboxylates (except formate) – is complicated by either post-depositional effects or existence of large non-biomass-burning sources. The quality of levoglucosan with respect to other proxies is not addressed here because of a lack of high-resolution profiles for this species, preventing a fair comparison. Several Greenland ice records of ammonium consistently indicate changing fire activity in Canada in response to past climatic conditions that occurred during the last millennium and since the last large climatic transition. Based on this review, we make recommendations for further study to increase reliability of the reconstructed history of forest fires occurring in a given region.
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Gowda, C., R. Seth, and N. Biswas. "Beneficial reuse of precast concrete industry sludge to produce alkaline stabilized biosolids." Water Science and Technology 57, no. 2 (January 1, 2008): 217–23. http://dx.doi.org/10.2166/wst.2008.011.
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The precast concrete industry generates waste called concrete sludge during routine mixer tank washing. It is highly alkaline and hazardous, and typically disposed of by landfilling. This study examined the stabilization of municipal sewage sludge using concrete sludge as an alkaline agent. Sewage sludge was amended with 10 to 40% of concrete sludge by wet weight, and 10 and 20% of lime by dry weight of the sludge mix. Mixes containing 30 and 40% of concrete sludge with 20% lime fulfilled the primary requirements of Category 1 and 2 (Canada) biosolids of maintaining a pH of 12 for at least 72 hours. The heavy metals were below Category 1 regulatory limits. The 40% concrete sludge mix was incubated at 52 °C for 12 of the 72 hours to achieve the Category 1 and 2 regulations of less than 1000 fecal coliform/g solids. The nutrient content of the biosolids was 8.2, 10 and 0.6 g/kg of nitrogen, phosphorus and potassium respectively. It can be used as a top soil or augmented with potassium for use as fertilizer. The study demonstrates that concrete sludge waste can be beneficially reused to produce biosolids, providing a long-term sustainable waste management solution for the concrete industry
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Lupwayi, N. Z., G. W. Clayton, J. T. O’Donovan, K. N. Harker, T. K. Turkington, and Y. K. Soon. "Soil nutrient stratification and uptake by wheat after seven years of conventional and zero tillage in the Northern Grain belt of Canada." Canadian Journal of Soil Science 86, no. 5 (November 1, 2006): 767–78. http://dx.doi.org/10.4141/s06-010.
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The distribution of NaHCO3-extractable nitrate-N, ammonium-N, phosphorus (P) and potassium (K) with soil depth (0 to 20 cm in 5-cm increments) at Fort Vermilion (58°23′N 116°02′ W), Alberta, was described in the 7th and 8th years of conventional and zero tillage following placement of red clover (Trifolium pratense) green manure (GM), field pea (Pisum sativum), canola (Brassica rapa) and monoculture wheat (Triticum aestivum) residues. Soil nitrate-N concentrations under zero tillage were greater than those under conventional tillage in the 0–5 cm soil layer, below which the concentrations were similar. Ammonium-N and K concentrations followed a similar pattern. However, soil P concentrations were usually not different between tillage systems in the 0–5 cm soil layer, but the concentrations decreased more under zero tillage than under conventional tillage at lower depths. A notable exception for soil phosphate was under canola residues, where the concentration was greater under zero tillage than under conventional tillage at all depths. Uptake of N, P or K by a subsequent wheat crop was usually greater (though not always significantly) under zero tillage than under conventional tillage, and there were no interactions between tillage and crop residue. Therefore, differences in nutrient stratification between the two tillage systems did not translate into differences in wheat nutrient uptake. Key words: Conservation tillage, crop rotation, nutrient uptake, soil nitrogen, soil phosphorus, soil potassium
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Qian, P., J. J. Schoenau, K. J. Greer, and Z. Liu. "Assessing plant-available potassium in soil using cation exchange membrane burial." Canadian Journal of Soil Science 76, no. 2 (May 1, 1996): 191–94. http://dx.doi.org/10.4141/cjss96-026.
Full textAbstract:
We assessed a method for extraction of plant-available potassium using a cation exchange membrane (CEM) burial technique. The study compared the amounts of K extracted by CEM burial with three reference chemical-based extractants for 19 soil samples representing a wide range of soil types in Saskatchewan, Canada and the People’s Republic of China. The three reference extractants were (1) 1 M NH4OAc, (2) a mixed solution of 0.01 M EDTA, 0.25 M NaHCO3 and 0.01 M NH4F and (3) 1 M HNO3. Potassium extractable by 1 M NH4OAc ranged from 37 mg kg−1 to 1889 mg kg−1 among the 19 soils. The K availability as predicted by CEM was significantly correlated with the reference methods with the strongest relationship (r2 = 0.94, P < 0.001) with the EDTA-NH4F test. To evaluate the relative ability of CEM and the conventional tests to predict K availability to plants, canola and wheat were grown on the 19 soils in the growth chamber and plant K uptake was compared with test-predicted K availability. All test methods revealed a similar ability to predict K availability with good correlation (r2 = 0.70, P < 0.001) with plant uptake. However, the CEM method showed its advantages in predicting plant availability in a variety of soil types with large coefficients of determination in both acidic and neutral to alkaline soil groupings. The CEM burial technique could be readily adopted in soil K availability analysis because of low cost and simplicity as well as its consistency over a wide range of soil types. Key words: Cation exchange membrane, burial technique, extraction, plant K availability, plant K uptake, soil test
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Garvin, J. L., K. R. Spring, and P. A. Santi. "Secretion of endolymph by semicircular canals of the shark." American Journal of Physiology-Renal Physiology 255, no. 4 (October 1, 1988): F711—F719. http://dx.doi.org/10.1152/ajprenal.1988.255.4.f711.
Full textAbstract:
The semicircular canals of the vestibular labyrinth of the dogfish shark, Squalus acanthias, may serve as a simple in vitro system for the study of the ionic transport mechanisms involved in endolymph formation. Electron microscopy showed that the epithelium was made up of at least three distinct cell types divided into separate regions running the length of the canals. Secretion of endolymph was studied in isolated canals by the split droplet method; when the lumens of the canals were filled with shark Ringer a potassium-rich fluid was secreted into the lumen at a rate of 0.34 microliter.cm-2.min-1. The K concentration of the secreted fluid averaged 112 mM; the calculated rate of K secretion was 2.3 mumol.cm-2.h-1, comparable to recent measurements in mammalian utricle. Fluid secretion was dependent on active transport and was inhibited by ouabain, bumetanide, or methazolamide in the external bathing solution. Fluid secretion was unaffected by the K channel blocker, Ba, in the luminal droplet or by the adenylate cyclase stimulator, forskolin, in the external bathing solution. For electrophysiological analysis, isolated canals were perfused in a chamber designed for voltage/current clamping; an axial wire was inserted into the canal lumen and constant-current pulses were passed to determine tissue resistance. When the luminal fluid was high-K Ringer, transepithelial potential difference was -1.1 mV (lumen negative) and resistance 37 omega.cm2. Dilution and bi-ionic potential measurements showed that the epithelium of the canals exhibited only slight cation selectivity. These results are consistent with a model for endolymph secretion involving cotransport secondary to the ion gradients created by the Na+-K+-ATPase.
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Hanes, J. A., S. J. Clark, and D. A. Archibald. "An 40Ar/39Ar geochronological study of the Elzevir batholith and its bearing on the tectonothermal history of the southwestern Grenville Province, Canada." Canadian Journal of Earth Sciences 25, no. 11 (November 1, 1988): 1834–45. http://dx.doi.org/10.1139/e88-173.
Full textAbstract:
Results of 40Ar/39Ar step heating for muscovite, potassium feldspar, and plagioclase from the ca. 1240 Ma Elzevir trondhjemite in the Central Metasedimentary Belt of the Canadian Grenville Province have been combined with earlier data and used to deduce a thermal history for the eastern Elzevir terrane following the Ottawan orogeny (1050–950 Ma). Muscovite yielded precise plateau dates of ca. 900 Ma, whereas the potassium feldspar displayed disturbed age spectra with ca. 730–760 Ma dates for broad "plateau" regions. This age difference could be explained by slow cooling or by thermal overprinting at 760–800 Ma that has updated the microcline. The plagioclase spectra provide evidence for a low-temperature hydrothermal event ca. 380 Ma ago that has generated sericite in saussurite and has caused partial argon loss from the microcline. This result agrees with the other plagioclase thermochronometry and paleomagnetism on the Cordova gabbro 25 km to the west but provides a lower estimate for the upper age bracket of this event. It is suggested that earlier models of protracted, post-700 Ma cooling of this part of the Grenville orogen may be a consequence of variable updating of plagioclase by this Devonian alteration event.Results of 40Ar/39Ar step heating for muscovite and microcline from the Bark Lake diorite in the Bancroft terrane are in agreement with earlier work in this area, and the cooling path of the Elzevir trondhjemite is seen to be indistinguishable, within the limitations of the method, from that of the Bark Lake diorite in the time period 1050–750 Ma.
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Norris, C. H., A. J. Ricci, G. D. Housley, and P. S. Guth. "The inactivating potassium currents of hair cells isolated from the crista ampullaris of the frog." Journal of Neurophysiology 68, no. 5 (November 1, 1992): 1642–53. http://dx.doi.org/10.1152/jn.1992.68.5.1642.
Full textAbstract:
1. A-type outward currents were studied in sensory hair cells isolated from the semicircular canals (SCC) of the leopard frog (Rana pipiens) with whole-cell voltage- and current-clamping techniques. 2. There appear to be two classes of A-type outward-conducting potassium channels based on steady-state, kinetic, pharmacological parameters, and reversal potential. 3. The two classes of A-type currents differ in their steady-state inactivation properties as well as in the kinetics of inactivation. The steady-state inactivation properties are such that a significant portion of the fast channels are available from near the resting potential. 4. The inactivating channels studied do not appear to be calcium dependent. 5. The A-channels in hair cells appear to subserve functions that are analogous to IA functions in neurons, that is, modulating spike latency and Q (the oscillatory damping function). The A-currents appear to temporally limit the hair cell voltage response to a current injection.