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51.
52.
Kfoury Miriana Auezova Lizette Greige-Gerges Hélène Fourmentin Sophie 《Environmental Chemistry Letters》2019,17(1):129-143
Environmental Chemistry Letters - There is a growing interest for aromatic and biological properties of essential oils as alternatives to synthetic chemicals and drugs. However, essential oils and... 相似文献
53.
Sophie Pierce Keith E. Schilling 《Journal of the American Water Resources Association》2023,59(5):913-928
Nutrient export from the agricultural Midwest threatens the Gulf of Mexico and new conservation practices are needed to reduce the loss of nutrient from subsurface tile drainage systems. Oxbows are natural waterbodies formed when a river cuts off a meander loop and water quality benefits of reconstructed oxbows are being increasingly recognized. In this study, we monitored four reconstructed oxbow sites (two tile-fed, two non-tile) over a 2-year period in north-central Iowa and assessed their capacity for NO3-N and dissolved reactive phosphorus (DRP) reductions. Water flow and quality monitoring of tiles, shallow groundwater, oxbow and receiving streams documented that the oxbows were dominated by tile drainage inputs. NO3-N concentrations were highest in the drainage tiles flowing into the tile-fed oxbows (mean 8–10 mg/L) and much lower in floodplain groundwater (<1–2 mg/L). Annual NO3-N loads into the tile-fed oxbows were substantially larger than input loads into the non-tiled oxbows. For the two tile-fed oxbows, the 2-year NO3-N retention efficiencies were very similar (0.76–0.77) and on a monthly basis, greater retention efficiencies were measured in summer and fall. DRP concentrations and loads into the tile-fed oxbows were too low to allow for meaningful estimates of retention. Reconstructing oxbows to receive tile drainage water should be considered a sustainable conservation practice for tile drainage treatment in agricultural areas. 相似文献
54.
Morné A. du Plessis 《Behavioral ecology and sociobiology》1991,28(4):291-295
Summary Observations were made of ten green (red-billed) woodhoopoe Phoeniculus purpureus flocks during the breeding season in order to quantify the relationship between flock size and the amount of food delivered to chicks. The study period was kept short specifically to minimize the effects of environmental stochasticity. Neither woodhoopoe feeding visit rates nor the total amount of food brought to chicks increased with flock size. Although nonbreeders did not increase the net rate of food provisioning to chicks, they reduced parental input in chick rearing, and hence energy expenditure by the breeding pair. However, over an 8-year study period, which includes data for 144 flock years, this did not result in increased breeding frequency or enhanced survival of breeders. There is thus no evidence that helpers' feeding contributions to young per se influence the indirect fitness of helpers. 相似文献
55.
Herman Friedl Smidt Stefan Englisch Michael Feichtinger Franz Gerzabek Martin Haberhauer Georg Jandl Robert Kalina Michael Zechmeister-Boltenstern Sophie 《Environmental science and pollution research international》2002,9(2):46-52
In the North Tyrolean Limestone Alps a site was investigated over a four-year period (1998–2001) in order to assess the nitrogen saturation status, the nitrogen budget (quantification of the net uptake of nitrogen by the canopy and of the nitrogen mineralization, nitrogen uptake from roots and N2O emission rates, proof of the origin of nitrate in the soil water with stable isotope analyses), and the effects of the actual nitrogen input on ground water quality. The main goals were to quantify the nitrogen input rate, the nitrogen pools in above-ground and below-ground compartments, nitrogen turnover processes in the soil as well as the output into the groundwater and into the atmosphere. The findings are based on continuous and discontinuous field measurements as well as on model results.While nitrogen input exceeded the Critical Loads of the WHO (1995), nitrogen deficiency and nutrient imbalances were verified by needle analyses. The atmospheric input of inorganic nitrogen was higher than the nitrogen output in 50 cm soil depth. A tracer experiment with15N helped to prove that not more than half of the applied nitrate could be discharged. This allows the conclusion that nitrogen is stored in the system and that the site cannot yet be said to be saturated with nitrogen. The same result was also obtained by modelling. In addition, it was proved that the nitrogen discharge did not stem from deposition but from processes within the system. 相似文献
56.
Modelling spatial zero-inflated continuous data with an exponentially compound Poisson process 总被引:1,自引:1,他引:0
Sophie Ancelet Marie-Pierre Etienne Hugues Benoît Eric Parent 《Environmental and Ecological Statistics》2010,17(3):347-376
A parsimonious model is presented as an alternative to delta approaches to modelling zero-inflated continuous data. The data model relies on an exponentially compound Poisson process,
also called the law of leaks (LOL). It represents the process of sampling resources that are spatially distributed as Poisson
distributed patches, each containing a certain quantity of biomass drawn from an exponential distribution. In an application
of the LOL, two latent structures are proposed to account for spatial dependencies between zero values at different scales
within a hierarchical Bayesian framework. The LOL is compared to the delta-gamma (ΔΓ) distribution using bottom-trawl survey data. Results of this case study emphasize that the LOL provides slightly
better fits to learning samples with a very high proportion of zero values and small strictly positive abundance data. Additionally,
it offers better predictions of validation samples. 相似文献
57.
58.
Rita Covas Morné A. du Plessis Claire Doutrelant 《Behavioral ecology and sociobiology》2008,63(1):103-112
Some studies on the effects of helpers in cooperatively breeding vertebrates show a positive effect of helper presence on
reproductive output whereas others find no effect. One possibility for this discrepancy is that helpers may have a positive
effect when breeding conditions are adverse, while their effect might go unnoticed under good conditions. We investigate this
hypothesis on sociable weavers Philetairus socius, a colonial cooperatively breeding passerine that inhabits a semi-arid region where breeding conditions vary markedly. We
used multivariate mixed models to analyse the effect of helpers on reproduction under contrasting environmental and social
conditions while controlling for parental and colony identity. We found that reproductive success in sociable weavers was
primarily influenced by nest predation and rainfall. In addition, colony size was negatively associated with hatching and
fledging success and number of young fledged per season. Helpers had a less prominent but significant influence on feeding
rates and reproductive outcome. In agreement with expectations, the presence of helpers counteracted some of the negative
effects of breeding in periods of low rainfall or in large colonies and was also associated with an increased number of young
fledged per season. Our results illustrate that the effect of helpers might be detectable mostly under unfavourable conditions,
but can contribute to improve reproductive performance in those situations. 相似文献
59.
Previous studies of upland roadside soils in Cumbria, that would normally be naturally acidic, have highlighted that (a) runoff from roads subjected to long-term road salting can dramatically raise soil pH down slope in upland areas; (b) the soil pH increase dramatically changes N cycling in soils down slope, increasing mineralisation of organic matter, ammonification, ammonium leaching down slope and nitrification and nitrate leaching; (c) the increase in nitrification substantially increases nitrate leaching to down-slope rivers, and this is readily detectable in field studies; and (d) loss of soil organic matter over decades of salting is so great that organic matter is no longer substantially solubilised by high salt concentrations found in soil solution below road drains. This paper tests and supports the hypothesis that such effects are minimal for more calcareous soil ecosystems. It examines the soil and soil solution chemistry on another Cumbrian upland highway, the A686 near Leadgate, Alston. Sodium % of soil CEC values for soil transects affected by spray containing road salt are similar at both the A6 and A686 sites. However, spatial trends in calcium, magnesium, ammonium, and nitrate concentrations as well as pH differ, as a direct result of the higher weathering rate of parent material and possibly also the presence of limestone walls above both spray-affected and control transects at the A686 site. 相似文献
60.
Hanane Bouchghoul Chloé Quelin Philippe Loget Féréchté Encha-Razavi Marie-Victoire Senat Lorraine Maheut Julie Galimand Sophie Collardeau-Frachon Lydie Da Costa Jelena Martinovic 《黑龙江环境通报》2018,38(10):772-778
We report a multiplex family with a GATA1 gene mutation responsible for a massive fetal cerebral hemorrhage occurring at 36 weeks. Two other stillbirth cousins presented with fetal hydrops and congenital hemochromatosis' phenotype at 37 and 12 weeks of gestation. Molecular screening revealed the presence of a c.613G>A pathogenic allelic variation in exon 4 of GATA1 gene in the 3 male siblings and their carrier mothers. The diagnosis of a GATA1 gene mutation may be suspected in cases of male fetuses with intracerebral bleeding, particularly if a history of prior fetal loss(es) and mild maternal thrombocytopenia are also present. 相似文献