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51.
某大型汽车厂设计采用多级过滤技术对工业废水处理尾水进行深度处理,再生后的中水回用于工业循环冷却水系统。介绍了多级过滤工艺的系统组成、工艺原理及处理效果。实际运行情况表明:采用多级过滤技术处理汽车工业废水处理后的尾水,系统运行稳定,出水水质良好,满足GB/T 19923—2005《再生水用作冷却用水的水质控制标准》的要求。  相似文献   
52.
Recent studies suggest that many organisms actively colonize the subterranean environment to avoid climatic stress, exploit new ecological opportunities and reduce competition and predation. Terrestrial salamanders are known to colonize the more stable subterranean habitats mainly to escape external climatic extremes, while the role of predation avoidance remains untested. To better understand the importance of predation, we used clay models of the cave salamander Speleomantes strinatii to compare the predation occurring in woodland and subterranean habitats. Models were positioned in three forests and in three caves in NW Italy. One-hundred eighty-four models were retrieved from the field and 59 (32%) were attacked by predators. Models were attacked on their head more often than expected by chance and, therefore, were perceived by predators as real prey items. In the woodlands, clay models showed a four-time higher probability of being attacked in comparison to caves, suggesting a different level of potential predation risk in these surface habitats. These findings are one of the first experimental evidences that, in terrestrial ecosystems, predation avoidance may contribute to the salamander underground colonization process.  相似文献   
53.
Many small terrestrial vertebrates exhibit limited spatial movement and are considerably exposed to changes in local environmental variables. Among such vertebrates, amphibians at present experience a dramatic decline due to their limited resilience to environmental change. Since the local survival and abundance of amphibians is intrinsically related to the availability of shelters, conservation plans need to take microhabitat requirements into account. In order to gain insight into the terrestrial ecology of the spectacled salamander Salamandrina perspicillata and to identify appropriate forest management strategies, we investigated the salamander’s seasonal variability in habitat use of trees as shelters in relation to tree features (size, buttresses, basal holes) and environmental variables in a beech forest in Italy. We used the occupancy approach to assess tree suitability on a non-conventional spatial scale. Our approach provides fine-grained parameters of microhabitat suitability and elucidates many aspects of the salamander’s terrestrial ecology. Occupancy changed with the annual life cycle and was higher in autumn than in spring, when females were found closer to the stream in the study area. Salamanders showed a seasonal pattern regarding the trees they occupied and a clear preference for trees with a larger diameter and more burrows. With respect to forest management, we suggest maintaining a suitable number of trees with a trunk diameter exceeding 30 cm. A practice of selective logging along the banks of streams could help maintain an adequate quantity of the appropriate microhabitat. Furthermore, in areas with a presence of salamanders, a good forest management plan requires leaving an adequate buffer zone around streams, which should be wider in autumn than in spring.  相似文献   
54.
Increasing levels of Heracleum persicum (golpar) in drinking water were studied in broilers. Two hundred and forty-one-day-old male chickens were allocated to one of six treatments: control, without added phytogenics nor probiotics in drinking water, and probiotics at recommended manufacturer’s level (P) or 1.0, 1.5, 2.0, and 2.5 ml/l of golpar extract solution (G1, G1.5, G2, and G2.5 treatments, respectively) in drinking water. As a result of this study, no linear or quadratic trends in the feed intake (FI) and feed conversion rate (FCR) due to golpar supplementation were found. Body weight gain, final body weight, and relative carcass weight showed a positive linear response with increasing levels of golpar supplementation. Neither golpar nor probiotics had effects on the percentages of edible parts of the carcass. Golpar supplementation levels caused a linear negative response of the albumin content in blood plasma, whereas both abdominal fat as percentage of carcass weight and uric acid levels in blood plasma linearly increased. The effects on Ig responses were only observed at 42 days of age and were similar in probiotics and the highest level of golpar supplementation. Based on our results, both probiotics and golpar supplementation could improve broiler performance and immune function.  相似文献   
55.
A Spanish ecodesign standard (the UNE 150301) is being used as a basic reference point in paving the way for the future ISO 14006 ecodesign standard which may foreseeably be passed in 2011. This article aims to analyze the experience regarding adoption of the UNE 150301 in Spain.Following an analysis of the standard’s structure, its objectives and scope, its real implementation process is then analyzed based on an exploratory qualitative study carried out in four Spanish companies that have been pioneers in adopting this environmental standard. The conclusion is drawn in the article that in all the cases analyzed, the greatest source of impact occurs in the phase in which the product is used and is related to energy consumption. Companies appear to be satisfied with the adoption of this standard and, in particular, point out that they have managed to reduce the environmental impact of their products. However, they draw attention to the fact that, to deal with certain instances of impact that increases in cost entail, administrative bodies need to establish mandatory regulations, as environmentally-friendly companies would otherwise lose competitiveness.  相似文献   
56.
Using information on a basic or “lifeline” level of domestic water use obtained from a water demand function based on a Stone–Geary utility function, a minimum water threshold of 128 m3 per household per year was estimated in a sample of municipalities in Southern Spain. As a second objective, water affordability indexes were then calculated that relate the cost of such lifeline to average municipal income levels. The analysis of the factors behind the differences in that ratio across Andalusian municipalities shows that the relative cost of purchasing the lifeline appears inversely related to average income levels, revealing an element of regressivity in the component of water tariffs affecting the least superfluous part of the household’s consumption. The main policy recommendation would involve redesigning water tariffs in order to improve access for lower income households to an amount of water sufficient to cover their basic needs. The proposed methodology could be applied to other geographical areas, both from developed and from developing countries, in order to analyze the degree of progressivity of the water tariffs currently in effect and in order to guide the design of more equitable regulatory policies.  相似文献   
57.
1. The HGPRT (Hypoxanthine‐Guanine‐Phospho‐Ribosyl‐Transferase) assay with Chinese Hamster V79 cells was used to measure the mutagenic effects of UV irradiation, potassium dichromate and nickel chloride. The agents were tested separately and in the combinations of UV plus nickel and dichromate plus nickel.

2. UV, Cr(VI) and Ni(II) were confirmed to be mutagenic in the V79 cell assay. The combination of UV(5J/m2) and Ni(II) (0.5 mM) caused a mutation rate 11.2 times above that corresponding to the sum of the individual mutation rates of these agents. The combined action of Cr(VI) (0.1 mM) and Ni(II) (0.5 mM) produced a mutation rate 2.8 fold above that corresponding to the sum of the individual rates of the separate agents.

3. The enhancing effect of nickel chloride on the mutagenicity of UV or Cr(VI) is interpreted by an interference of Ni(II) with the repair of DNA lesions.  相似文献   
58.
The pesticide usages are controlled by comparing residue concentrations in treated commodities to legally permitted maximum levels (MRLs) determined based on supervised trials designed to reflect likely maximum residues occurring in practice following authorised use. The number of trials available may significantly affect the accuracy of estimated maximum residues. We conducted a study with synthetic lognormal distributions with mean of 1 and standard deviations of 0.8 and 1.0, which reflect the residue distributions observed in practice. The likely residues in samples were modelled by drawing random samples of size 3, 5, 10 and 25 from the synthetic populations. The results indicate that the estimations of highest residues (HR), used for calculation of short-term intake, and the MRLs, serving as legal limits, are very uncertain based on 3–5 trials indicated by the calculated HR0.975/HR0.025 and MRL0.975/MRL0.025 ratios of 12 and 9, and 13 and 10, respectively, which question the suitability of such trials for the intended purpose. As the 95% range of HR and MRL rapidly decreases with number of trials, ideally ≥15 but minimum 6–8 trials should be used for estimation of HR and MRL according to the current typical practice of Codex Alimentarius.  相似文献   
59.
60.
The central role played by livestock in the livelihoods of rural households in the developing world is seldom fully appreciated by policy makers, development agencies and donors. Knowledge gaps in the geographic distribution and environmental determinants of farming systems, especially if viewed through the livestock lens, compound this problem. We have produced a map of pastoral, agro-pastoral and mixed farming systems across Eastern Africa, by analysing datasets collected in the framework of livelihood analysis. Input data were gathered between 2000 and 2007 by various emergency and development agencies for Djibouti, Eritrea, Kenya, Somalia, Uganda and parts of Ethiopia and Sudan. A quantitative definition of the production systems is adopted, based on the ratio of livestock- to crop-derived income. The resulting livelihood-based map of livestock production systems was compared through correspondence analysis to an alternative livestock production systems map, produced independently from environmental data. Convergence between the two mapping approaches was evident. The geographic distribution of the livestock production systems was also modelled using multivariate analysis of remotely sensed and other geospatial datasets. Models show high statistical accuracy, and were thus used to fill the gaps in the observed distribution of livestock production systems. Finally, selected environmental factors underpinning the systems (agro-climatology, human and livestock populations and land cover) were analysed in detail, enabling the livestock production systems to be characterized in terms of them. The regional scope of the map, as well as its direct link with a vast amount of livelihood information, render it a valuable tool for a range of development and research applications, including those related to global change.  相似文献   
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