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Definitions of the notions of soil resilience and degradation of the soil-vegetation cover are suggested. These problems are considered with respect to vulnerable tundra ecosystems. The analysis of available experimental data made it possible to obtain empirical equations characterizing the relationships between the plant productivity and the soil properties. These equations can be used to predict the degree of soil degradation under particular types of technogenic loads and the soil and vegetation potential for the natural restoration or artificial rehabilitation of the soil-vegetation cover in tundra ecosystems. The results obtained can be applied for the development of optimal nature management strategies in the areas of oil and gas fields in the north. 相似文献
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Booth AJ Stogdale L Grigor JA 《The Canadian veterinary journal. La revue veterinaire canadienne》1984,25(1):2-6
Salmon poisoning disease in dogs has previously been reported in North America only along the western coast of the U.S.A. This paper presents the findings from eight affected dogs recently diagnosed on Vancouver Island, Canada. The clinical signs shown by these dogs were lethargy, anorexia, pyrexia and lymph node enlargement. The causative agent, Neorickettsia helminthoeca was observed in macrophages obtained from lymph node aspirates. This organism is transmitted to dogs in cysts of the fluke Nanophyetus salmincola salmincola within the tissues of the salmon or trout. The presence of fluke eggs in the feces of dogs showing typical signs is very suggestive of a diagnosis of salmon poisoning disease. Appropriate treatment, including chloramphenicol or oxytetracycline and fluid therapy, resulted in recovery. Prevention of salmon poisoning disease in endemic areas can be achieved by advising owners against allowing their dogs to eat raw salmon or trout. We suggest, based on the diagnoses made in these eight dogs, that Vancouver Island now be considered an endemic area for salmon poisoning disease. 相似文献
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V. Ya. Grigor’ev 《Eurasian Soil Science》2007,40(11):1217-1226
Semi-empirical equations for describing the erosive and transporting capacities of low-depth flows with account for their interaction with eroded soil were developed and experimentally and theoretically substantiated. These equations can form the basis for a unified model of rill erosion under irrigation, rainfall, and snowmelt runoff conditions. 相似文献
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Snejana Doncheva Zlatimira Stoyanova Katya Georgieva Dimitrina Nedeva Rumyana Dikova Grigor Zehirov Ana Nikolova 《植物养料与土壤学杂志》2006,169(2):247-254
The effect of copper (Cu) excess (1.5, 4.7, 31, 78, 156 μM) and exogenously supplied succinate on plant growth, chlorophyll content, chlorophyll fluorescence, and isoenzym profiles of some antioxidant enzymes in maize plants was studied. Excessive Cu supply led to a reduction in the relative growth rate (RGR), tolerance index (TI), chlorophyll a and chlorophyll b contents, and the quantum yield of PSII electron transport in the light‐adapted state (ΦPSII). Copper treatment induced several changes in the anionic and cationic peroxidases (PODs), as well as superoxide dismutase (SOD) isoenzyme profiles. After 8 d of 78 μM–Cu treatment, two new anionic and two new cationic peroxidase isoenzymes in the roots were registered. Copper applied at concentrations above 31 μM resulted in higher levels of manganese superoxide dismutase (Mn‐SOD) in the roots and Cu,Zn‐superoxide dismutase (Cu,Zn‐SOD) in the leaves. However, the addition of Na‐succinate (200 μM) to the root medium prior to Cu treatment increased the capacity of the plants to partially overcome Cu toxicity. 相似文献
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A procedure was developed on the basis of the experimental-theoretical equation for calculating the parameters of soil erosion resistance (the bottom eroding velocity of flow), the principles of the erosion resistance theory, the experimentally obtained relationships between the main erosion parameters of Tajikistan soils (the size of water-stable aggregates and their cohesion), and other properties (the initial water content, the lumpiness, the contents of physical clay and humus, the porosity ratio, and the lower plasticity limit). For practical purposes, a simpler procedure is recommended to evaluate and map the erosion resistance of irrigated lands in the areas of typical serozems and mountain cinnamonic soils of Tajikistan from minimum initial information (the texture, lumpiness, and density of the soils and the content of plant roots). 相似文献
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Reconstructing past ocean pH-depth profiles 总被引：1，自引：0，他引：1
Measurement of boron isotope compositions in species of planktonic foraminifera that calcified their tests at different depths in the water column are used to reconstruct the pH profile of the upper water column of the tropical ocean. Results for five time windows from the middle Miocene to the late Pleistocene indicate pH-depth profiles similar to that of the modern ocean in this area, which suggests that this method may greatly aid in our understanding of the global carbon cycle. 相似文献
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ZF Ren ZP Huang JW Xu JH Wang P Bush MP Siegal PN Provencio 《Science (New York, N.Y.)》1998,282(5391):1105-1107
Free-standing aligned carbon nanotubes have previously been grown above 700 degreesC on mesoporous silica embedded with iron nanoparticles. Here, carbon nanotubes aligned over areas up to several square centimeters were grown on nickel-coated glass below 666 degreesC by plasma-enhanced hot filament chemical vapor deposition. Acetylene gas was used as the carbon source and ammonia gas was used as a catalyst and dilution gas. Nanotubes with controllable diameters from 20 to 400 nanometers and lengths from 0. 1 to 50 micrometers were obtained. Using this method, large panels of aligned carbon nanotubes can be made under conditions that are suitable for device fabrication. 相似文献
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S. V. Grigor’ev T. V. Shelenga V. S. Baturin Yu. V. Sarana 《Russian Agricultural Sciences》2010,36(4):262-264
The composition and content of fatty acids in oil of ruderal hemp seeds collected in the Volga, Southern, Urals, Siberian,
and Far Eastern federal districts are studied. The content of tetrahydrocannabinol is assessed. 相似文献