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931.
David A. P. Paterson Winifred Ijomah James F. C. Windmill 《International Journal of Sustainable Engineering》2016,9(2):130-140
While many studies and reviews into the practices conducted by industry and academia to recycle and remanufacture carbon fibre-reinforced plastic (CFRP) exist, to date no investigation exists which regards the correctness of the use of the terms recycling and remanufacturing. As such, this paper seeks to analyse the CFRP reuse industry’s attempt to recycle and remanufacture manufacturing waste CFRP and end-of-life (EOL) CFRP with an emphasis on the terminology used to describe these practices. Firstly, this paper presents a justification of the importance of using EOL terminology correctly; outlining the benefits and problems associated with using the correct and incorrect terminology. This paper finds that in the case of CFRP remanufacturing, terminology is being applied incorrectly and in the case of CFRP recycling, particular care should be taken when applying the term recycled to CFRP or stating that CFRP has been recycled. Further, this paper proposes new terminology (in keeping with EU directives) which could be adopted by industry and academia working in this area. This paper also finds that in the case of remanufacture, CFRP is incapable of being remanufactured. 相似文献
932.
Delgado J. F. de la Osa O. Salvay A. G. Cavallo E. Cerrutti P. Foresti M. L. Peltzer M. A. 《Journal of Polymers and the Environment》2021,29(10):3242-3251
Journal of Polymers and the Environment - In the last decades, cellulose nanoparticles have been widely used to reinforce polymeric materials due to their strength and their wide availability in... 相似文献
933.
The Fleet (southern England) is a stable (ca. 5,000 years) coastal saline lagoon that supports a population of Alcyonidium resembling the common coastal epiphyte, Alcyonidium gelatinosum (L.). A combination of morphological, reproductive, and ecological characters was used to compare lagoonal and non-lagoonal proximate populations. Comparisons revealed a difference in the timing of spawning, considered to be related to the temporally restricted availability of viable substrata within the lagoonal basin. Allochronous spawning and spatial separation together suggest that the lagoonal taxon is reproductively isolated. The two populations were further compared with seven other coastal populations of Alcyonidium using randomly amplified polymorphic DNA (RAPD) analysis. The results confirm the individuality of the lagoonal taxon but also a close relationship with three A. gelatinosum populations. We present and consider four hypotheses that may account for the presence of this genetically distinct taxon: (1) diversification within the Fleet; (2) colonisation from another lagoon; (3) non-indigenous species status; and (4) introduction by shipping or other anthropogenically mediated dispersal mechanism. Significant diversification on the time scale involved has been demonstrated for isolated freshwater environments and, therefore, is feasible within a saline lagoon. Hypothesis 1 and, to a lesser extent, hypothesis 2 are consistent with the recognition of individual lagoons as 'biogeographic' islands of importance for their unique or characteristic biodiversity. The study also represents the first example of concordant morphological, reproductive, and genetic diversification in a marine bryozoan. 相似文献
934.
Christophe Pélabon Jean-Michel Gaillard Anne Loison Christine Portier 《Behavioral ecology and sociobiology》1995,37(5):311-319
We examined data on sex-specific differences in neonatal weight, litter size and adult female body weight in 32 populations of polygynous ungulates of 18 different species to test for the existence of a trade-off between sex-biased maternal care and the total amount of maternal expenditure. This corresponds to an extension of the hypothesis of Byers and Moodie (1990) that sex-biased maternal care is limited by a high level of maternal expenditure. We did not find any relationship between sex-biased care and two measures of total maternal expenditure. We highlighted high intraspecific variability in sex-biased care and very low intraspecific variability in total maternal expenditure. Even when this between-population variability in sex-biased care was accounted for, no relationship between sex-biased maternal care and maternal expenditure was detected. Apart from difficulties in finding suitable measures for both variables, two other reasons may account for the lack of a relationship between sex-biased maternal care and total maternal expenditure. Firstly, male offspring seem to be more affected than female offspring by harsh environmental conditions. This may lead to the variation observed in the extent of sex-specific differences in birth weight within a single species. If we assume that for a given maternal expenditure reproductive costs incurred by mothers are highest during harsh conditions, this could indicate the existence of a trade-off between sex-biased maternal care and maternal expenditure at the intra-specific level, thereby supporting the Byers and Moodie hypothesis. Secondly, polygyny is only a poor predictor of sex-biased care and factors such as compensatory growth or extended periods of growth may be expected to modify predictions for different species. Thus, environmental conditions and relative effects of maternal care on male and female lifetime reproductive success are better predictors of sex-biased care than total maternal expenditure.Communicated by P.M. Kappeler 相似文献
935.
Recruitment data for 18 marine fish stocks are smoothed using 10 parametric families of probability distributions. Comparative fit of the 10 families is assessed by means of the maximized log-likelihood. Results indicate that the gamma distribution provides an overall good fit in the right-hand tail of the data, but that some adjustment to the gamma distribution is called for in the left-hand tail. Weight functions and weighted distributions are suggested as one means of achieving the needed adjustment. 相似文献
936.
Reis AP Patinha C Ferreira da Silva E Sousa AJ 《Environmental geochemistry and health》2012,34(2):229-241
The Marrancos gold mineralisation has a chemical assemblage of Fe–As–Se–Bi–Au–Ag–Te–(Cu–Pb–Zn–Sn–W). The −200 mesh of 144
topsoil samples was analysed by ICP–MS to determine total contents of 53 elements that include potentially harmful elements
like Cd, As and Pb. The soil geochemistry shows that some trace elements occur in considerably high concentrations. On the
basis of data for total metal concentrations, 10 topsoil samples were selected to carry out a metal fractionation study using
a selective extraction method. A set of four leaches of increasing strength was used sequentially in the soil samples. Across
the study area, there is some evidence of past mining and exploration activity, indicating that these soils may be locally
disturbed. The shallow mineralised quartz veins were exploited for gold by the Romans. Several galleries were constructed
during the 2nd World War, probably for the exploration of quartz–cassiterite–wolframite veins. However, the main mineralised
body in depth was never explored. The results of metal fractionation show different partitions for the three elements. Total
Cd concentrations in these soils are low, with a median value of 0.1 mg/kg. In average, 12% of total Cd is adsorbed by clays
and/or co-precipitated with carbonates, and 19% is bounded to Fe–Mn oxyhydroxides. However, the low concentrations indicate
that the metal does not represent an immediate risk to human health. For Pb, metal fractionation shows that, on average, 22%
of Pb is adsorbed by amorphous Fe and Mn oxides, but the samples from the northern part of the area have the major fractions
of Pb in soluble forms. The low probability of exposure in this part of the study area decreases the risk posed by this heavy
metal. Total As concentrations in the Marrancos soils are extremely high. A large area has As concentrations above 1,000 mg/kg.
For As, metal fractions in the sulphide phase vary between 84 and 98% in the studied samples. But one sample has 20% of total
As in easily reducible forms, corresponding to a partial concentration of 1,800 mg/kg that has a high probability of being
bioavailable. The most labile As forms occur at the southern part of the area, where the probability of exposure is higher
and the risk of human health increases in the same order. From the three studied potentially harmful elements, As is certainly
the element of concern. 相似文献
937.
Invisible floral larcenies: microbial communities degrade floral nectar of bumble bee-pollinated plants 总被引:2,自引:0,他引:2
The ecology of nectarivorous microbial communities remains virtually unknown, which precludes elucidating whether these organisms play some role in plant-pollinator mutualisms beyond minor commensalism. We simultaneously assessed microbial abundance and nectar composition at the individual nectary level in flowers of three southern Spanish bumble bee-pollinated plants (Helleborus foetidus, Aquilegia vulgaris, and Aquilegia pyrenaica cazorlensis). Yeasts were frequent and abundant in nectar of all species, and variation in yeast density was correlated with drastic changes in nectar sugar concentration and composition. Yeast communities built up in nectar from early to late floral stages, at which time all nectaries contained yeasts, often at densities between 10(4) and 10(5) cells/mm3. Total sugar concentration and percentage sucrose declined, and percentage fructose increased, with increasing density of yeast cells in nectar. Among-nectary variation in microbial density accounted for 65% (H. foetidus and A. vulgaris) and 35% (A. p. cazorlensis) of intraspecific variance in nectar sugar composition, and 60% (H. foetidus) and 38% (A. vulgaris) of variance in nectar concentration. Our results provide compelling evidence that nectar microbial communities can have detrimental effects on plants and/or pollinators via extensive nectar degradation and also call for a more careful interpretation of nectar traits in the future, if uncontrolled for yeasts. 相似文献
938.
Mirco Bundschuh Michael C. Newman Jochen P. Zubrod Frank Seitz Ricki R. Rosenfeldt Ralf Schulz 《Environmental science and pollution research international》2013,20(10):7341-7347
Although generally misunderstood, the p value is the probability of the test results or more extreme results given H0 is true: it is not the probability of H0 being true given the results. To obtain directly useful insight about H0, the positive predictive value (PPV) and the negative predictive value (NPV) may be useful extensions of null hypothesis significance testing (NHST). They provide information about the probability of statistically significant and non-significant test outcomes being true based on an a priori defined biologically meaningful effect size. The present study explores the utility of PPV and NPV in an ecotoxicological context by using the frequently applied Daphnia magna reproduction test (OECD guideline 211) and the chemical stressor lindane as a model system. The results indicate that especially the NPV deviates meaningfully between a test design strictly following the guideline and an experimental procedure controlling for α and β at the level of 0.05. Consequently, PPV and NPV may be useful supplements to NHST that inform the researcher about the level of confidence warranted by both statistically significant and non-significant test results. This approach also reinforces the value of considering α, β, and a biologically meaningful effect size a priori. 相似文献
939.
940.
Lakshminarayana JS O'Neill HJ Jonnavithula SD Léger DA Milburn PH 《Environmental pollution (Barking, Essex : 1987)》1992,76(3):201-210
Preliminary results are reported from a co-operative study between Agriculture Canada and Environment Canada on environmental impacts of atrazine measured in a field stream receiving agricultural drainage. Systematically, tile drained plots of known crop rotation, area, flow and pesticides use were used in the study. A maximum tile drainage concentration of 13.9 microg liter(-1) atrazine was measured while the maximum measured stream concentration was 1.89 microg liter(-1). Phytoplankton and zooplankton samples were collected on a bi-monthly basis during the growing season. The study indicated possible negative impacts of low concentrations of atrazine on planktonic drift populations, when natural stream flow was reduced, resulting in a lower dilution capacity. A 20 m section of the stream was affected by the tile drainage waters as measured by the resident biological community. Both atrazine and ambient environmental conditions were felt to be contributing to the measured results. No negative impacts on planktonic drift populations were evident beyond 50 m downstream of the tile drainage and stream confluence. 相似文献