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991.
Batch tests and diffusion tests were performed to analyze the efficiency of a protective barrier in a landfill consisting of compacted soil with 10% bentonite compared to the results obtained for only compacted soil and for compacted soil covered with a 1-mm-thick HDPE geomembrane; the soil and leachate were collected from the Rio das Ostras Landfill in Rio de Janeiro, Brazil. The diffusion tests were performed for periods of 3, 10 and 60 days. After the test period, the soil pore water was analyzed and the profiles for chloride, potassium and ammonium were determined along a 6-cm soil depth. The results of the batch tests performed to define sorption parameters were used to adjust the profiles obtained in the diffusion cell experiment by applying an ion transfer model between the interstitial solution and the soil particles. The MPHMTP model (Multi Phase Heat and Mass Transfer Program), which is based upon the solution of the transport equations of the ionic contaminants, was used to solve the inverse problem of simultaneously determining the effective diffusion coefficients. The results of the experimental tests and of the model simulation confirmed that the compacted soil with 10% bentonite was moderately efficient in the retention of chloride, potassium and ammonium ions compared to the configurations of compacted soil with a geomembrane and compacted soil alone, representing a solution that is technically feasible and requires potentially lower costs for implementation in landfills.  相似文献   
992.
Asian knotweeds (Fallopia spp.) are considered one of the world’s most invasive species. Restoring habitats dominated by these exotic species requires a better understanding of the importance of abiotic factors controlling the invasive knotweeds performance. We used observational data obtained on the embankment of the Isère River (France) to study the performance of Fallopia spp. under different soil, light, and disturbance conditions. On the Isère riverbanks, light intensity assessed by light quantity transmitted through canopy was the most important factor explaining the variability observed on knotweed performance expressed as above-ground biomass per square meter. Asian knotweeds were more productive under intensive light conditions. Alternatively other factors such as mowing (twice a year), soil fertility, soil texture, position on the bank or exposure to the sun had no significant effect on knotweed biomass production. We conclude that decreasing light resources, for example, by increasing competitive pressure on sites dominated by Asian knotweeds could be included in management plans to control the populations of this invasive taxon.  相似文献   
993.
This paper estimates rural household-level forest reliance in the western highlands of Guatemala using quantitative methods. Data were generated by the way of an in-depth household income survey, repeated quarterly between November 2005 and November 2006, in 11 villages (n = 149 randomly selected households). The main sources of income proved to be small-scale agriculture (53 % of total household income), wages (19 %) and environmental resources (14 %). The latter came primarily from forests (11 % on average). In the poorest quintile the forest income share was as high as 28 %. All households harvest and consume environmental products. In absolute terms, environmental income in the top quintile was 24 times higher than in the lowest. Timber and poles, seeds, firewood and leaf litter were the most important forest products. Households can be described as ‘regular subsistence users’: the share of subsistence income is high, with correspondingly weak integration into regional markets. Agricultural systems furthermore use important inputs from surrounding forests, although forests and agricultural uses compete in household specialization strategies. We find the main household determinants of forest income to be household size, education and asset values, as well as closeness to markets and agricultural productivity. Understanding these common but spatially differentiated patterns of environmental reliance may inform policies aimed at improving livelihoods and conserving forests.  相似文献   
994.
The Jarcho–Levin syndrome is a specific form of spondylocostal/spondylothoracic dysostosis. There have been various classifications of this syndrome. We present the case of a severe prenatal Jarcho–Levin syndrome, diagnosed by ultrasound examination during the first trimester of pregnancy in a family with no previous medical history of an affected child. X-ray exploration, high-resolution spiral computed tomography and autopsy confirmed the diagnosis. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
995.
The capacity to distinguish colony members from strangers is a key component in social life. In social insects, this extends to the brood and involves discrimination of queen eggs. Chemical substances communicate colony affiliation for both adults and brood; thus, in theory, all colony members should be able to recognize fellow nestmates. In this study, we investigate the ability of Dinoponera quadriceps workers to discriminate nestmate and non-nestmate eggs based on cuticular hydrocarbon composition. We analyzed whether cuticular hydrocarbons present on the eggs provide cues of discrimination. The results show that egg recognition in D. quadriceps is related to both age and the functional role of workers. Brood care workers were able to distinguish nestmate from non-nestmate eggs, while callow and forager workers were unable to do so. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   
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Many studies have shown the importance of colorful ornamentation in mate choosiness or intrasexual conflict. However, research on color ornaments has focused mainly on birds, lizards or fish, but remains practically unknown in other animal groups such as turtles. In addition, female ornaments and their relation with sexual selection also remain almost unknown. Here, we measured the coloration of the shell and the limb stripes of male and female Spanish terrapins Mauremys leprosa and explored the existence of sexual dichromatism and the relation of color characteristics with body size and health state estimated from the immune response to the injection of an antigen (phytohaemagglutinin test). Our results showed that shell coloration, which could be constrained by natural selection to be cryptic, changed with body size, but did not differ between sexes. In contrast, females had brighter and less ultraviolet-saturated and more orange-saturated limb stripes than males. In females, interindividual variation in limb stripe coloration was related with body size and immune response suggesting that this coloration may inform honestly about multiple traits that could be important in sexual selection. In contrast, coloration of limb stripes of males was duller than in females, and was not related with any trait suggesting that coloration is not important in sexual selection for males.  相似文献   
1000.
Five organic Sloping and Mountainous Olive Plantation Production Systems (SMOPS) have been studied in four olive-producing areas in four European countries (Spain, Italy, Greece and Portugal). Results indicate that these SMOPS provide ecological, economic and social benefits to the regions in which they are located, although most of these benefits are not strictly limited to the organic production systems. Erosion control and organic matter balance remain significant issues in four of the SMOPS and we suggest that subsidy support should be conditional on the implementation of additional soil and water conservation measures that should be provided with specific funding. Most of the SMOPS will remain dependent on a similar level of support in order for olive production to remain economically feasible. The lower profitability compared to non-organic olive production systems suggests that there is limited scope for expansion of organic olive production, although in the study areas where there is little such production, such as Western Crete (Greece) and Basilicata-Salerno (Italy) the scope remains great. The analysis of the reasons for the beneficial effects of olive cultivation in the areas studied indicates that in most cases soil management techniques adopted in or recommended for organic production systems could provide similar benefits in other production systems as well.  相似文献   
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