The SAHGA model to calculate the Spatial Ammoniacal Heterogeneity at the soil surface after fertiliser Granule Application     

Edith?Le?CadreEmail author  Sophie?Génermont  Farooq?Azam  Sylvie?Recous 《Biology and Fertility of Soils》2004,40(3):178-180

After dissolution of fertiliser granules, a high nitrogen concentration is recovered in the immediate vicinity of granules, which may enhance damaging processes like nitrite accumulation or ammonia volatilisation. Based on the diffusion equations of Cranck, the granule-soil microsite was modelled to obtain the actual fertilised surface plot and the effective rate of N application on this surface. Parameterisation of the diffusion coefficient of solutes consisted of a temperature and soil texture correction. The model was tested against an experimental data set obtained from soil incubations at two soil water contents (21.2% m³ m^–3 and 28.3% m³ m^–3) and two temperatures (4°C and 25°C) by comparing NH₄⁺ recovery at various distances from the granules. The simulated radius of the granule-soil microsite was more affected by the water content than by the temperature. The model is very accurate because 95–100% of total NH₄⁺ applied was recovered in the modelled surface depending on the experimental conditions (temperature and water content). The model was simple enough to be easily integrated into larger models dealing with surface-applied granule fertilisers.  相似文献   

Evaluation of the in vivo anthelmintic properties of Mitragyna inermis (Willd.) as a livestock dewormer against parasitic hematophagous worm Haemonchus contortus infections in different breeds of lambs     

Alowanou  Géorcelin Goué  Azando  Erick V. B.  Adenilé  Adam D.  Koudandé  Delphin O.  Chrysostome  Christophe A. M.  Hounzangbé-Adoté  Sylvie M. 《Tropical animal health and production》2020,52(1):309-319

Tropical Animal Health and Production - Gastrointestinal (GI) nematodes remain a major constraint on livestock production throughout the world. This study assessed the in vivo efficacy of the...  相似文献   

Estimating illegal and unreported catches from marine ecosystems: a basis for change   总被引：4，自引：0，他引：4  

Tony J Pitcher  Reg Watson  Robyn Forrest  Hreiðar Þór Valtýsson  & Sylvie Guénette 《Fish and Fisheries》2002,3(4):317-339

To evaluate the impacts of fishing on marine ecosystems, the total extraction of fish must be known. Putting a figure on total extraction entails the difficult task of estimating, in addition to reported landings, discards, illegal and unmandated catches. Unreported catches cast various types of shadow, which may be tracked and estimated quantitatively. Some shadows of unreported catches are reviewed, for example, an innovative, well‐funded NGO publicizes illegal catch in the Southern Ocean. For various reasons, official figures often have the implicit but unacceptable assumption that such categories are null. We present an estimation procedure based on adjustment factors taken from observer reports, correspondents and published information that track changes in a regulatory regime, and hence reflect incentives and disincentives to misreport. Monte Carlo simulations address uncertainty using multiple sources of information to provide upper and lower estimates. Once in place, this method provides preliminary estimates that may be refined without disruption. The method is demonstrated for fisheries in Iceland and Morocco. We use a ‘by‐species’ approach for Icelandic cod and haddock, while the Moroccan catch is divided into demersal and pelagic categories. Results suggest that Icelandic cod catches may have been underestimated by between 1 and 14% at different times, and haddock by between 1 and 28%. Underestimation of Moroccan catches appears to have been as much as by 50%. These case studies show that it is possible to obtain estimates of misreporting, even when direct data are lacking. Our method encourages transparency because sources of information are presented so that uncertain values are easily identified, offering a basis for comment, collaboration and refinement in estimating illegal and unreported fishing.  相似文献   

Haemocyte responses of blue mussels (Mytilus edulis L.) transferred from a contaminated site to a reference site: can the immune system recuperate?     

Elise Mayrand  Sylvie D St-Jean  & Simon C Courtenay 《Aquaculture Research》2005,36(10):962-971

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Characterization and quantification of proteins in lecithins     

Martín-Hernández C  Bénet S  Marvin-Guy LF 《Journal of agricultural and food chemistry》2005,53(22):8607-8613

Several methods for extraction and quantification of proteins from lecithins were compared. Extraction with hexane-2-propanol-water followed by amino acid analysis is the most suitable method for isolation and quantification of proteins from lecithins. The detection limit of the method is 15 mg protein/kg lecithin, and the quantification limit is 50 mg protein/kg. The relative repeatability limits for samples containing 0-500 and 500-5000 mg protein/kg sample were 12.6 and 7.5%, respectively. The protein recovery ranged between 101 and 123%. The protein content has been determined in different kinds of lecithins. The results were as follows: standard soy lecithins (between 232 and 1338 mg/kg), deoiled soy lecithin (342 mg/kg), phosphatydylcholine-enriched soy lecithins (not detectable and 163 mg/kg), sunflower lecithins (892 and 414 mg/kg), and egg lecithin (50 mg/kg). The sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein patterns of the standard soy and sunflower lecithins are very similar to those of soy flour. The protein profile of the egg lecithin shows several bands with a broad range of molecular masses. The molecular masses of the main proteins of soy lecithins and soy flour have been determined by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) and ranged from 10.5 to 52.2 kDa. Most of the major proteins from soy and sunflower lecithins identified by MALDI-MS and electrospray tandem MS belong to the 11S globulin fraction, which is one of the main fractions of soy and sunflower seeds. In addition, the seed maturation protein P34 from the 7S globulin fraction of soy proteins has also been identified in soy lecithins. This protein has been reported as the most allergenic protein in soybean.  相似文献   

Landscape composition influences roe deer habitat selection at both home range and landscape scales     

Nicolas Morellet  Bram Van Moorter  Bruno Cargnelutti  Jean-Marc Angibault  Bruno Lourtet  Joël Merlet  Sylvie Ladet  A. J. Mark Hewison 《Landscape Ecology》2011,26(7):999-1010

Understanding how patterns of habitat selection vary in relation to landscape structure is essential to predict ecological responses of species to global change and inform management. We investigated behavioural plasticity in habitat selection of roe deer (Capreolus capreolus) in relation to variable habitat availability across a heterogeneous agricultural landscape at the home range and landscape scales. As expected, woodland was heavily selected, but we found no functional response for this habitat, i.e. no shift in habitat selection with changing habitat availability, possibly due to the presence of hedgerows which were increasingly selected as woodlands were less abundant. Hedgerows may thus function as a substitutable habitat for woodlands by providing roe deer with similar resources. We observed a functional response in the use of hedgerows, implying some degree of landscape complementation between hedgerows and open habitats, which may in part compensate for lower woodland availability. We also expected selection for woodland to be highest at the wider spatial scale, especially when this habitat was limiting. However, our results did not support this hypothesis, but rather indicated a marked influence of habitat composition, as both the availability and distribution of resources conditioned habitat selection. There was no marked between-sex difference in the pattern of habitat selection at either scale or between seasons at the landscape scale, however, within the home range, selection did differ between seasons. We conclude that landscape structure has a marked impact on roe deer habitat selection in agricultural landscapes through processes such as landscape complementation and supplementation.  相似文献   

Environmental,historical, and contextual determinants of vegetation cover: a landscape perspective   总被引：1，自引：1，他引：0  

de Blois  Sylvie  Domon  Gérald  Bouchard  André 《Landscape Ecology》2001,16(5):421-436

We formulated and tested models of relationships among determinants of vegetation cover in two agroforested landscapes of eastern North America (Haut Saint-Laurent, Quebec, Canada) that differed by the spatial arrangement of their geomorphic features and intensity of agricultural activities. Our landscape model compared the woody plots of each landscape in terms of the relative influence of environmental attributes, land use history (1958 – 1997), and spatial context (i.e., proximity of similar or contrasting land cover). Our vegetation model evaluated the relative contribution of the same sets of variables to the distributions of herbs, trees, and shrubs. Relationships were assessed using partial Mantel tests and path analyses. Significant environmental and contextual differences were found between the vegetation plots of the two landscapes, but disturbance history was similar. Our vegetation model confirms the dominant effect of historical factors on vegetation patterns. Whereas land-use history overrides environmental and contextual control for trees, herbaceous and shrub species are more sensitive to environmental conditions. Context is determinant only for understory species in older, less-disturbed plots. Results are discussed in relevance to vegetation dynamics in a landscape perspective that integrates interactions between environmental and human influences.  相似文献   

Utilisation d'anticorps spécifiques d'une fraction obtenue par chromatographie d'exclusion pour une amélioration de la caractérisation sérologique deRhizoctonia solani Kühn AG3     

Sylvie Le Coz-Gillet  Lucien Hingand 《Potato Research》1991,34(2):149-158

La purification d'un extrait mycélien soluble d'une souche deR. solani AG3 par chromatographie d'exclusion permet de recueillir une fraction antigénique. Une lapine est immunisée par voie intradermique. L'immunsérum titre 0,125 par la technique de double-diffusion en agarose. Différentes techniques sérologiques (immunodiffusion, électrotransfert suivi de révélation des fractions antigéniques, coloration immunoenzymatique du mycélium) sont appliquées à des souches deR. solani AG1, AG2, AG3, AG4, AG5, AG6, AG7, AGBI et deCeratobasidium CAG1, CAG2, CAG3, CAG4 et CAG5. Le sérum se révèle spécifique des souches AG3. A soluble mycelial extract ofR. solani AG3 was purified by size exclusion chromatography. Five peaks were present in the elution profile: the first was well defined and of large volume. It was retained to immunise a female rabbit by intradermic injection. The titre of the antiserum determined by double immuno-diffusion in agarose was 0.125. The antiserum was tested on isolates ofR. solani AG1, AG2, AG3, AG4, AG5, AG6, AG7, AGB1 and ofCeratobasidium CAG1, CAG2, CAG3, CAG4 and CAG5 (Table 1) using three different methods:

–	- immunodiffusion with the test material adjusted to 3 mg/ml of proteins. Only AG3 isolates formed a single precipitation line (Fig. 1).
–	- electrotransfer and immuno-blotting. Test samples containing 8 mg/ml of proteins were electrophoresed under natural conditions in a discontinuous system. The proteins were then electrotransferred to a nitrocellulose membrane. Immunoenzymatic staining showed that only one band was present in AG3 isolates (Fig. 2).
–	- immunoenzymatic labelling of the mycelium demonstrated the presence of dark granules on the cell wall of only AG3 isolates (Fig. 3).

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Genetically encoded sensors for ions and metabolites     

Sakiko Okumoto  Karen Deuschle  Marcus Fehr  Melanie Hilpert  Ida Lager  Sylvie Lalonde 《Soil Science and Plant Nutrition》2013,59(7):947-953

Many of the genes encoding important trans porters and metabolic enzymes have been identified over the last ten years. Moreover it has been possible to study the biochemical properties of the corresponding proteins in great detail. It is expected that by 2,010 biochemical functions will have been assigned to many of the products of the approximately 30,000 Arabidopsis genes. We will get closer to understanding the biological function of the gene products by systematic analysis of mutants using knock-out and TILLING approaches. Metabolomics initiatives complement these approaches by providing insight into the changes in cellular ion and metabolite profiles in the mutants, thus giving information essential for the construction of cellular and whole plant models. However, one important dataset especially relevant to multicellular organisms is lacking: the knowledge of the spatial and temporal profiles of ions and metabolite levels at cellular and subcell ular levels. To address this issue, we have developed protein-based nanosensors for several metabolites, providing a set of tools for the determination of cytosolic and subcellular ion (e.g. iron and zinc) and metabolite levels in real time using fluorescence-based microscopy. The prototypes of these sensors were shown to function in vitro and also in vivo, i.e. in yeast and in mammalian cell cultures. One future goal is to expand the set of sensors to a wider spectrum of targets by using the natural spectrum of periplasmic binding proteins from bacteria and by computational design of proteins with altered binding pockets. Application of nanosensor technology to plant cells and tissues will help to elucidate the special and temporal distribution of ions and metabolites.  相似文献   

Spatial attributes of fire regime in eastern Canada: influences of regional landscape physiography and climate     

Nicolas Mansuy  Yan Boulanger  Aurélie Terrier  Sylvie Gauthier  André Robitaille  Yves Bergeron 《Landscape Ecology》2014,29(7):1157-1170

The characterization of the fire regime in the boreal forest rarely considers spatial attributes other than fire size. This study investigates the spatial attributes of fires using the physiography of the landscape as a spatial constraint at a regional scale. Using the Canadian National Fire Database, the size, shape, orientation and eccentricity were assessed for 1,136 fires between 1970 and 2010 in Quebec’s boreal forest and were summarized by ecodistrict. These spatial metrics were used to cluster 33 ecodistricts into homogeneous fire zones and then to determine which environmental variables (climate, topography, hydrography, and surficial deposits) influence the spatial attributes of fires. Analyses showed that 28 out of 33 ecodistricts belonging to a given fire zone were spatially contiguous, suggesting that factors driving the spatial attributes of fire are acting at a regional scale. Indeed, the orientation and size of fires vary significantly among the zones and are driven by the spatial orientation of the landscape and the seasonal regional climate. In some zones, prevailing winds during periods conducive to fire events parallel to the orientation of the landscape may favour the occurrence of very large fires (>100,000 ha). Conversely, an orientation of the landscape opposite to the prevailing winds may act as a natural firebreak and limit the fire size and orientation. This study highlights the need to consider the synergistic relationship between the landscape spatial patterns and the climate regime over the spatial attributes of fire at supra-regional scale. Further scale-dependant studies are needed to improve our understanding of the spatial factors controlling the spatial attributes of fire.  相似文献