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91.
92.
Marie Ange Ngo Bieng Thomas Perot François de Coligny François Goreaud 《European Journal of Forest Research》2013,132(5-6):841-850
Spatial pattern has a key role in the interactions between species in plant communities. These interactions influence ecological processes involved in the species dynamics: growth, regeneration and mortality. In this study, we investigated the effect of spatial pattern on productivity in mature mixed forests of sessile oak and Scots pine. We simulated tree locations with point process models and tree growth with spatially explicit individual growth models. The point process models and growth models were fitted with field data from the same stands. We compared species productivity obtained in two types of mixture: a patchy mixture and an intimate mixture. Our results show that the productivity of both species is higher in an intimate mixture than in a patchy mixture. Productivity difference between the two types of mixture was 11.3 % for pine and 14.7 % for oak. Both species were favored in the intimate mixture because, for both, intraspecific competition was more severe than interspecific competition. Our results clearly support favoring intimate mixtures in mature oak–pine stands to optimize tree species productivity; oak is the species that benefits the most from this type of management. Our work also shows that models and simulations can provide interesting results for complex forests with mixtures, results that would be difficult to obtain through experimentation. 相似文献
93.
Marie Peeters Coline ClossonJean-François Beckers PhD Marc Vandenheede PhD 《Journal of Equine Veterinary Science》2013
During competition, stress may affect riders and horses. This stress can affect health, welfare, and/or performance. Our aim was to quantify stress levels during competition in horses and riders. We also searched relationships between these stress levels and performance. Twenty riders and 23 horses were followed up during a show-jumping event (26 courses) held at a riding school. Regular saliva samples taken from horses and riders were assayed to evaluate cortisol levels. We studied salivary cortisol evolution during the days of competition. There was no correlation between instantaneous sampling on horses and their riders. However, we did find a parallel between horse and rider salivary cortisol evolution curves, with a similar peak, reached 20 minutes after the course. The increase was stronger in riders than in horses. Correlations appeared between salivary cortisol concentration and performance, but stress in both partners seems to have an opposite influence on performance. Riders who showed a higher salivary cortisol increase were awarded more penalties, whereas horses that showed a higher increase in salivary cortisol performed better. Stress level measurement in rider–horse pairs would thus lead to improvement in competition conditions and performance, for horses as well as for riders. 相似文献
94.
New Forests - In reclaimed waste rocks slopes, the soil cover spread for revegetation is prone to erosion. This soil needs to be immediately protected from soil erosion by above and belowground... 相似文献
95.
OBJECTIVE: Renewed focus on public health has brought about considerable interest in workforce development among public health nutrition professionals in Canada. The present article describes a situational assessment of public health nutrition practice in Canada that will be used to guide future workforce development efforts. METHODS: A situational assessment is a planning approach that considers strengths and opportunities as well as needs and challenges, and emphasizes stakeholder participation. This situational assessment consisted of four components: a systematic review of literature on public health nutrition workforce issues; key informant interviews; a PEEST (political, economic, environmental, social, technological) factor analysis; and a consensus meeting. FINDINGS:Information gathered from these sources identified key nutrition and health concerns of the population; the need to define public health nutrition practice, roles and functions; demand for increased training, education and leadership opportunities; inconsistent qualification requirements across the country; and the desire for a common vision among practitioners. CONCLUSIONS: Findings of the situational assessment were used to create a three-year public health nutrition workforce development strategy. Specific objectives of the strategy are to define public health nutrition practice in Canada, develop competencies, collaborate with other disciplines, and begin to establish a new professional group or leadership structure to promote and enhance public health nutrition practice. The process of conducting the situational assessment not only provided valuable information for planning purposes, but also served as an effective mechanism for engaging stakeholders and building consensus. 相似文献
96.
Shinkaruk S Lamothe V Schmitter JM Fructus A Sauvant P Vergne S Degueil M Babin P Bennetau B Bennetau-Pelissero C 《Journal of agricultural and food chemistry》2008,56(16):6809-6817
Two carboxylic acid haptens of glycitein were synthesized, with a spacer arm at the C2 position. They differed in the length of the spacer arm, with the length of the spacer arms being three or four carbon atoms, and were named Delta3-glycitein and Delta4-glycitein haptens, respectively. The different haptens were coupled to bovine serum albumin (BSA), and the coupling efficiency was assessed by MALDI mass spectrometry. Polyclonal antibodies were generated against the BSA conjugates. An additional conjugate of Delta4-glycitein hapten was generated with swine thyroglobulin (Thyr). Enzyme-linked immunosorbent assays (ELISAs) based on the competition between free glycitein and Delta4-glycitein-Thyr conjugates for specific antibodies were developed. The IC50 of the standard curves was 15.6 ng mL(-1) with anti-Delta3-glycitein and 62.5 ng mL(-1) with anti-Delta4-glycitein, that is, 10.9 and 44 pmol/well, respectively. With the Delta3-glycitein antibody, interassay and intra-assay variations were 12.2 and 11.5%, respectively. Specificity tests did not show any significant cross-reaction with any other soy isoflavone. This specificity is not influenced by the length of the spacer arm. The assay was validated by measurements performed on plasma samples as well as on soy-based foodstuffs and on soy-based food supplements. 相似文献
97.
Novák J Tykva R Wimmer Z Pavlík M Prouza M Hlavsová K Zarevúcka M 《Journal of agricultural and food chemistry》2008,56(15):6604-6608
Two bacteria were isolated from sand RQ30, characterized as Bacillus simplex and Bacillus sp. strain 05 (GenBank EU399813 ), and were used as biocatalysts for a hydrolytic assay of stability of the cis or trans isomers of ethyl N-{2-{4-{[2-(butanoyl)oxycyclohexyl]methyl}phenoxy}ethyl}carbamate, which are among insect hormonogen substances (juvenogens). The stability tests were performed using simple modeling under laboratory conditions. The structures of the products were assigned as ethyl (1 R,2 R)- N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl}carbamate and ethyl (1 S,2 R)- N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl}carbamate on the basis of (1)H and (13)C NMR, IR, and FAB-MS analyses. 相似文献
98.
Espaa María Luisa Baret Frdric Weiss Marie 《Agricultural and Forest Meteorology》2008,148(10):1553-1562
Digital hemispherical photography poses specific problems when deriving leaf area index (LAI) over sloping terrain. This study proposes a method to correct from the slope effect. It is based on simple geometrical considerations to account for the path length variation within the canopy for cameras pointing vertically. Simulations over sloping terrain show that gap fraction increases up-slope while decreasing down-slope. As a consequence of this balance between up- and down-slope effects, effective LAI estimates derived from inversion of the Poisson model are marginally affected for low to medium slopes (<25°) and LAI (LAI < 2). However, for larger slopes and LAI values, estimated LAI values may be strongly underestimated. The proposed correction was evaluated over four forested sites located over sloping terrain. Results indicate that in these conditions (LAI between 0.6 up to 3.0, clumped canopies with relatively erectophile leaf distribution), the effect of the slope (between 25° and 36°) was moderate as compared to other potential sources of problems when deriving LAI from gap fraction measurements, including clumping, leaf angle inclination and spatial sampling. 相似文献
99.
Carine Hue Marie Tremblay Daniel Wallach 《Journal of Agricultural, Biological & Environmental Statistics》2008,13(3):355-365
Bayesian methods seem well adapted to dynamic system models in general and to crop models in particular, because there is
in general prior information about parameter values. The usefulness of a Bayesian approach has often been pointed out, but
actual applications are rather rare. A major difficulty is including the elements of the covariance matrix of model errors
in the treatment. We treat the specific case of balanced data and an unstructured covariance matrix. In our particular case
this is a 3 × 3 matrix. We illustrate two methods for deriving a sample from the joint posterior density for the crop model
parameters and the error covariance matrix parameters. The first method is based on importance sampling, the second on Metropolis
within Gibbs sampling. We derive an instrumental density for the former and a proposal density for the latter which are adapted
to this type of model and data. Both algorithms work well and they give very similar results. The example concerns a model
for sunflowers during rapid leaf growth. The ultimate goal is to use the model as a decision aid in predicting disease risk. 相似文献
100.
Lou Frotté Julien Ringelstein Dominique Monti Marie Robert Christophe Pécheyran Nadia Améziane Hélène Tabouret 《Ecology of Freshwater Fish》2020,29(1):132-144
All native fishes living in the Caribbean island rivers are considered diadromous but few species have been validated as diadromous. In Guadeloupe (Lesser Antilles) as well as in the other tropical islands, the riverine habitats are subject to strong anthropogenic pressure due to resource modifications or dams. The management of fish biodiversity requires knowledge concerning their life history traits and behaviour that are still unknown for most species at a local scale and at the whole distribution area of the species. In a Guadeloupe river, we inferred the migratory patterns of four freshwater fishes common to Caribbean rivers by the analysis of otolith microchemistry. We found two species Eleotris perniger (Eleotridae) and Sicydium plumieri (Gobiidae) to be completely amphidromous with a marine larval phase and a freshwater adult phase. Agonostomus monticola (Mugilidae) was also found to be amphidromous in this system. The fourth species Gobiesox cephalus (Gobiesocidae) showed elemental ratios suggesting an estuarine larval phase and was defined as “limited amphidromous”. The identification of such life history traits, with limited dispersion abilities, argues for specific management measures in tropical island rivers at a basin scale for the conservation of biodiversity. 相似文献