Landscape Ecology - To analyze the scales at which landscape structure influences ecological processes, two approaches with different underlying ecological assumptions exist; the usual threshold... 相似文献
In the first section, the author presents a detailed analysis of fundamental processes of pedological evolution in the light of the latest findings as to biogeochemical, mineralogical and granulometric aspects of pedogenesis on crystalline aluminosilicate rocks. This analysis is based on the nature of various geochemical weathering phenomena, on the one hand, and on problems related to the organization of plasmic elements (pédoplasmation) and their possible transfers as particles, on the other. With reference to the latter aspect, two major types of “pedogenesis” may be considered: “associative” pedogenesis in which plasma-skeleton links are kept, and “dissociative” pedogenesis in which plasma—skeleton links are disrupted and plasma is redistributed.Then, in the second section, a structuring of fundamental pedogenetic processes is proposed, based on the observation of three major phyla at the earth surface.Phylum I: Process with predominant biogeochemical evolution without plasma formation or with plasma destruction.Phylum II: Process with predominant biogeochemical evolution with plasma formation and reorganization in situ.Phylum III: Process with predominant textural evolution with plasma mobilization and redistribution. 相似文献
The metabolism of benomyl was studied in carrots treated with high rates of benomyl, and in strawberries and apples treated at normal rates. The same metabolites were observed in both cases though, at normal rates, their concentrations were low but significant. Detected by means of gas-liquid chromatography they were: carbendazim, 2-aminobenzimidazole (2-AB), benzimidazole, 2-aminobenzonitrile, o-phenylene-diamine and the conjugates of carbendazim and 2-AB. o-Phenylenediamine has not hitherto been reported as a metabolite of benomyl. Two unidentified compounds were also observed by gas-liquid chromatography; their mass spectra were obtained by means of combined gas-liquid chromatography and mass spectrometry. 相似文献
A new acidic derivative of the fungicide fenpiclonil was synthesized containing a methyl group on the alpha-position of the carboxyl function of N-carboxymethyl-3-cyano-4-(2,3-dichlorophenyl)pyrrole. The phloem mobility of the resulting N-(1-carboxyethyl)-3-cyano-4-(2,3-dichlorophenyl)pyrrole was comparable with that of the former compound, but was higher at external pH 5.0. Unlike the derivatives previously synthesized, it was comparable with fenpiclonil in its fungicidal activity against the pathogenic fungus Eutypa lata. 相似文献
A sheep-pox virus strain has been adapted and multiplied in primary lamb kidney cell cultures. The main characteristics of the strain have been verified in vitro after clones were isolated, and the results confirmed its identity. The safety and the potency of the strain have been investigated in sheep.
The inoculation of the strain to sheep was followed by a post-vaccinal reaction materialised by a nodule at the site of inoculation and an increase of temperature by about 1°C. No reactions adversely affecting pregnancy have been noted. Immunisation was demonstrated by an increase in the level of neutralising serous antibodies and protection against the pathogenic virus. The immunity tended to decrease during the second year after primovaccination and a yearly booster vaccination appeared to be necessary. Primovaccination of lambs over 2 months of age produced a better immunity, especially when the lambs were born from vaccinated ewes.
This strain forms the active principle of a freeze-dried vaccine containing no adjuvant of the immunity. 相似文献
A series of derivatives of the phenylpyrrole fungicide fenpiclonil was synthesized in which a carboxyl group was present at various sites of this non-phloem-mobile molecule. Using the Kleier model, all these acidic analogues were predicted to be moderately phloem-mobile, especially the N-substituted derivatives. One of these latter molecules, N-carboxymethyl-3-cyano-4-(2,3-dichlorophenyl)pyrrole, exhibited some fungicidal activity on the pathogenic fungus Eutypa lata, and was then tested as a phloem-mobile pesticide in the Ricinus system. The compound was indeed mobile in the sieve tubes and was not degraded to fenpiclonil in the phloem sap under our experimental conditions. Its concentration in the sap was closely correlated to the percentage of the undissociated form of the molecule in the external medium, and was similar under acidic conditions (external pH 4.6-5.0) to that of the herbicide glyphosate. 相似文献
Mid-infrared spectroscopy was applied to the analysis and discrimination of Cognacs and other distilled drinks (Armagnacs, whiskies, brandies, bourbons, rums, and counterfeit products). Strong correlations were found between dry extract spectra, polyphenolic dry extract spectra, and the total polyphenol concentration of samples, notably of Cognacs. Principal component analysis applied to spectral data made it possible to emphasize the importance of dry extract data when a distinction is made between Cognacs and Armagnacs, whiskies, bourbons, and rums, and of polyphenol concentration when Cognacs, brandies, and counterfeit products are separated. Ninety-six percent of samples in the test set were correctly assigned to Cognacs and non-Cognacs by partial least-squares discriminant analysis. 相似文献
The aim of the study was to test three different hand-milking techniques (“pull down”, “thumb in”, and “full hand grip”) and
their effects on milk production and teat treatment. This is important since milk production in many tropical areas still
rely on hand-milking. The study was carried out at a peri-urban farm in the Bobo-Dioulasso area in Burkina Faso. Twelve indigenous
Zebu cows in early lactation were used in the study. The sequences of the treatments (hand-milking techniques) and the milkers
were balanced for carry-over effects between successive periods and days, respectively. The sequences were constructed by
using special Latin squares. Yield and composition of saleable milk was not affected by milking technique but there were differences
between the milkers in milk yield. There was also a significant interaction for saleable milk yield between milker and milking
technique. Hemoglobin in milk was measured as an indicator of teat damage. The hemoglobin content was numerically higher in
post-milking strip milk samples than in saleable milk. It was concluded that the amount of milk removed depends mainly on
the milker and how well the milking technique works for the individual milker. No effect of milking technique was observed
on teat treatment. 相似文献