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141.
Environmental Modeling & Assessment - This study applies a large battery of state-of-the-art nonlinear unit root tests to examine the stationarity properties of carbon dioxide emission series...  相似文献   
142.
Environmental Science and Pollution Research - Oil sludge washing (OSW) with surfactants and co-solvents is used to recover the oil, and this process leaves some residuals (sediments and surfactant...  相似文献   
143.
Environmental Science and Pollution Research - The dyes Auramine and Auramine O are used in several industrial products, despite the scarce information regarding their ecotoxicity. The aim of the...  相似文献   
144.
Mesozooplankton distribution, metabolism and feeding were investigated in the slope water oceanic anticyclonic eddy (SWODDY) AE6 during the cruise Gigovi-0898, which was conducted in August 1998 in the Bay of Biscay. According to the distribution of isotherms at 200 m depth, the sampling area was divided into three zones: SWODDY centre (C), edge (E) and outside the SWODDY (O). Multivariate analysis identified four different zooplankton assemblages. Such separation was closely related to the structure of the SWODDY, with each grouping associated to a particular zone of this mesoscale structure. Thus, two of the groups were located at the SWODDY centre and outside (groups C and O, respectively), whereas the two remaining station groupings (TWE and TNS) were situated at the SWODDY margin. The assemblages C and O differed clearly from each other in their taxonomic composition. In contrast, TWE and TNS were separated because of the differences observed in numerical abundance rather than by a different composition. Some taxa were found exclusively outside the SWODDY, while others were confined to the centre, suggesting a large degree of isolation of the SWODDY with respect to the surrounding waters. Phytoplankton and mesozooplankton biomass followed a similar pattern, with highest values in the SWODDY centre, although the differences between zones were significant only for phytoplankton. The highest grazing impact for both phytoplankton standing stock (3.4%) and primary production (12.7%) was observed outside the SWODDY. Ammonium released by mesozooplankton accounted for between 25.3% (outside the SWODDY) and 44.4% (SWODDY centre) of total phytoplankton nitrogen demands. The percentage of total phosphorus required to be fulfilled by phosphate excretion ranged from 14.0% at the edge to 17.5% outside. Mesozooplankton underwent intense vertical migrations, especially at the SWODDY edge. The role of the mesozooplankton in the biological pump releasing metabolic end-products below 200 m at night time is proposed as one of the main sources of downward export of biogenic material in these systems.Communicated by S.A. Poulet, Roscoff  相似文献   
145.
Moreno DA  Víllora G  Ruiz JM  Romero L 《Chemosphere》2003,52(6):1031-1040
Soils contaminated with low levels of heavy metals and other trace elements are now frequently used for vegetable growing. In this situation, heavy metals and trace elements from these polluted soils may accumulate in the agricultural plants being grown in them and thereby enter the human food chain. The objectives of this study are to elucidate the effects of growth conditions, manipulated by the crop covers, on the phytoaccumulation of elements, and to investigate the conceivable influences of these conditions on the plant biochemistry. In three consecutive years of field experiments, open air (T(0)), and floating rowcover treatments (T(1): perforated polyethylene 50 micrometers; T(2): polypropylene 17 gm(-2)) were used to produce different environmental conditions for the growth of Chinese cabbage [Brassica rapa L. (Pekinensis group) cv. 'Nagaoka 50']. Five samplings (whole tops) were carried out from transplanting to harvest and measurements of B, Al, Ag, Si and Ca concentration as well as phenolics (orto-diphenols, total phenols and anthocyanins), pectic fractions, amino acids (histidine, phenylalanine and tyrosine) and polyphenol oxidase activity, were carried out in samples. The T(1) (perforated polyethylene sheet) gave greater B, Al, Ag and Si concentration and phytoextraction (in weight units) than the open-air control. These findings can help to develop new cost-effective techniques for phytoremediation as the application of plastic covers in the field. The build-up of heavy metals in those crops would make the product less suitable for human consumption.  相似文献   
146.
Environment, Development and Sustainability - The objective of this work was to analyse the relations between innovation management and organisational sustainability in a Brazilian higher education...  相似文献   
147.
Female birds deposit in the yolks of eggs substantial amounts of androgens, such as testosterone and androstenedione. These androgens have been shown to speed up nestling development, induce a fast development of ornaments and increase dominance in adults. Experiments in several species have reported that females invest greater amounts of androgens in the eggs fathered by attractive males, suggesting that yolk androgen is a costly investment for either the offspring or the mother. There is some evidence that nestling immunocompetence may be partially suppressed by high levels of yolk androgens, but it is not known whether this is also the case for females. We tested this hypothesis in the house martin by inducing an immune challenge through an injection of sheep red blood cells, a standard challenge of the humoral immune system. Experimental birds laid eggs with lower amounts of yolk androstenedione than controls, and there was a similar non-significant trend for testosterone. Furthermore, the probability of laying a replacement clutch was higher for birds that had laid a first clutch with relatively high levels of yolk testosterone. These results suggest that yolk androgen deposition is limited by immune costs in the female, and that only females in good condition may afford to invest high levels of androgen in eggs in this species.  相似文献   
148.
Variations in the gene encoding the low-density lipoprotein receptor (LDLR) can cause familial hypercholesterolemia (FH), one of the most common inherited metabolic disorders in humans. The functional effects of the p.Gln92Glu and p.Asn564His alterations are predicted as benign, but the c.313 + 1G>C and p.Lys799_Phe801del changes are believed to cause disease. Although p.Gln92Glu and c.313 + 1G>C have been observed only in Spain, p.Asn564His and p.Lys799_Phe801del are widespread in Western Europe. In order to estimate the ages (t generations) of these four variants of the gene, to determine their possible origin and to consider the influence of age and selective pressure on their spread, we analyzed 86 healthy individuals and 126 FH patients in Spain. Most of the FH patients investigated carried two of these four LDLR variants simultaneously, while only one patient carried three of them simultaneously. Haplotype analyses were based on five LDLR SNPs: c.81T>C, c.1413G>A, c.1725C>T, c.1959T>C and c.2232G>A. The results suggest that p.Gln92Glu and c.313 + 1G>C arose at about the same time (99 and 103 generations ago, respectively) in the CACTG haplotype and that p.Asn564His and p.Lys799_Phe801del appeared in the CGCCG haplotype and might be slightly more recent variations (92 and 95 generations ago, respectively). Low selective pressures could explain the maintenance of these variants in spite of their ages. The origin of p.Gln92Glu and c.313 + 1G>C appears to be in Spain whereas p.Asn564His and p.Lys799_Phe801del could have been introduced in Spain by Celtic migrations in the seventh to fifth centuries BC.  相似文献   
149.
During the last 50 years, mechanisation of the rural environment, and, more recently, the Common Agricultural Policy have led to profound changes in agrarian landscapes throughout Europe, and in particular in the rich and diverse Mediterranean landscapes (Meeus et al., 1990). In the north-east of the Iberian Peninsula, a small area of hedgerow landscape persists as a remnant of what was once an important centre for livestock production. This paper presents the results of a study carried out in this area with the aim of clarifying the relationship between the structural change of this hedgerow landscape and the evolution of farming practices developed by its owners and workers. It also considers these farmers’ perceptions of their pastures, of their farms and of the region. Up to 61 statistically significant relationships were found between the physical landscape characteristic variables and the socio-economical variables. Results depict a hedgerow landscape determined by the combination of two management models. Here, and contrary to conclusions reported in similar literature, traditional pasture activity leads to a weaker hedgerow network than a farming model based on crop cultivation. Management guidance required to move from the current situation towards a hedgerow landscape supporting both biodiversity and agrarian activity is discussed.  相似文献   
150.
Non-random sex allocation may occur whenever the expected reproductive value of sons and daughters differs, as is the case when the sexes differ in susceptibility to environmental conditions or maternal effects (e.g. egg size and hatch order). Under such circumstances, covariation between egg and clutch characteristics and egg sex may be expected, and this covariation should vary with maternal state or ecological conditions. In this 2-year study (2007–2008), we examined sex allocation in relation to egg and clutch traits in the yellow-legged gull Larus michahellis, a species where male chicks are larger and more susceptible to harsh rearing conditions than female ones. In 2008, eggs were more likely male early in the season in two- but not three-egg clutches, and large eggs were more likely males late in the season. No egg/clutch traits predicted egg sex in 2007. Within-clutch egg mass asymmetry (the difference in egg mass between the first- and last-laid eggs) predicted sex in both years. In 2007, clutches with smaller egg mass variation were more likely to contain males, while in 2008 this relationship held for the last-laid egg and was reversed for the preceding egg(s). Laying order and sex of the previous egg did not predict egg sex, providing no evidence of sex-specific oocyte clustering. Thus, the relationships between egg sex and egg/clutch traits differed among years, suggesting a phenotypically plastic response of females to extrinsic conditions, and involved within-clutch egg mass asymmetry, a trait likely reflecting variation in maternal quality and/or reproductive tactics, which has been largely neglected in previous studies of sex allocation.  相似文献   
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