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71.
The effect of six glyphosate concentrations on growth rate and aflatoxin B1 (AFB1) production by Aspergillus section Flavi strains under different water activity (aW) on maize-based medium was investigated. In general, the lag phase decreased as glyphosate concentration increased and all the strains showed the same behavior at the different conditions tested. The glyphosate increased significantly the growth of all Aspergillus section Flavi strains in different percentages with respect to control depending on pesticide concentration. At 5.0 and 10 mM this fact was more evident; however significant differences between both concentrations were not observed in most strains. Aflatoxin B1 production did not show noticeable differences among different pesticide concentrations assayed at all aW in both strains. This study has shown that these Aspergillus flavus and A. parasiticus strains are able to grow effectively and produce aflatoxins in high nutrient status media over a range of glyphosate concentrations under different water activity conditions.  相似文献   
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Organic farming is a form of agriculture that excludes the use of synthetic fertilizers, pesticides, and genetically modified organisms. These fertilizers have been traditionally overused in conventional farming to avoid lost revenue, but this often not does not take into account the potential contamination of aquifers and river due to nitrate leaching. Transition to organic farming practices could provide an instrument to reduce contamination and increase potential income. It is difficult to determine to what extent those fertilizers could have been used within a complete traceability of the production process. In this experiment, we evaluated the use of (15)N/(14)N isotopic discrimination in sweet pepper plants to test the hypothesis that synthetic fertilizers significantly reduce (15)N/(14)N compared with exclusively organic practices. Therefore, three common types of organic manures (sheep, hen, or horse) were applied at a rate of 8 kg m(-2) with or without synthetic fertilizer amendments under fully controlled environmental and irrigation conditions. Results indicate that (i) use of synthetic fertilizers significantly reduced (15/14)N(2)vsN(2)atm compared with treatments that only received water; (ii) with respect to the plant organs, old leaves and fruits were more sensitive to the synthetic fertilizer additions with reductions in (15/14)N(2)vsN(2)atm of 24.1 and 27.8%, respectively; and (iii) independently of the organic manure used, no additional fertilization (synthetic or organic) is required before 106 days after transplanting at that dosage because plant fresh weight was not reduced.  相似文献   
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Semipermeable membrane devices (SPMDs) were used for measurements in air of twelve polycyclic aromatic hydrocarbons (PAHs) in two Genoa locations, both on building roofs, distant 300 m from each other. The first, site A, was in front a dismissing steel complex and the second, site B, was in an urban area overlooking a busy thoroughfare. SPMDs were deployed contemporary at the two sites, in nine monthly samplings, from April 2007 to May 2008. The amount of sequestered PAHs, in sites A and B, ranged between 61–267 ng SPMD?1 d?1 and 50–535 ng SPMD?1 d?1, respectively.PAHs profiles highlighted seasonal differences and suggested the possible role of different PAHs sources in the two areas. In particular, the contribution of remediation works of the steel complex was observed in site A. Moreover, a naphthalene leak from a tank, into the former industrial area, and a fire broke out near site A, were registered by time-integrated measurements of SPMDs.However, the strong dependence between amount of sequestered PAHs and air temperature needs further studies to distinguish between uptake rate variability and seasonal contribution of different sources. Finally, to measure air concentrations with reasonable accuracy, it should be very important to have certified sampling rates for all individual PAHs.  相似文献   
74.
Mussel biomonitors are widely used as screening tools for polybrominated diphenyl ethers (PBDEs) in marine and aquatic environments. This study determined elimination rate coefficients (k(tot)) for eight PBDE and five PCB congeners in the freshwater mussel, Elliptio complanata, over a 120d depuration period. Elimination of BDE 15, 28, 47, 75 and 100 was similar to PCBs of equivalent hydrophobicity and negatively related to chemical K(OW). Rapid elimination of BDE 190 and an inferred rapid elimination of BDE 183 indicate mussels are capable of biotransformation of certain highly brominated PBDEs. Time to 90% steady state ranged from 48 to 66d for di- and tribromoDE congeners and from 91 to >250d for tetra- to hexabromoDE congeners. Given the long time periods required for steady state, mussel accumulated PBDE residues should be interpreted in the context of calibrated bioaccumulation models.  相似文献   
75.
In developing countries, participatory conservation initiatives have been criticized for many reasons, mainly for excluding marginalized groups which have led to unequal benefits. Using concepts from the literature on participation, conservation, and political ecology, this research explored the participation of marginal groups, i.e., poor, women, lower caste, and landless, in management institutions in Nepal’s Annapurna Conservation Area. Field work for this research was conducted through the use of interviews and participant observation during August–October 2010. Results show that although marginal groups were involved in local management institutions, their representation was minimal and had not led to meaningful participation or empowerment to influence the decisions being made in conservation and development programs. Our study findings indicate that the involvement of marginal groups in local initiatives is complex and influenced by several factors. The study concludes that the Annapurna Conservation Area Project needs to re-orient its conservation projects by adopting a more inclusive form of participation and move beyond the quota system.  相似文献   
76.
A geochemical study of a red soil derived from plioquaternary materials was carried out. The soil was located in a region of complex geomorphology and pedologic evolution, with particular characteristics of a Mediterranean climate associated with processes of alteration, rubification, gleying (hydromorphism) and argillization. The depth distribution of 27 trace elements was studied in order to determine the amounts of these elements in the soil and its tendency. The mineralogy of the clay fraction was also studied along with other physico-chemical properties to elucidate in terms of attributes meaningful for viticulture. The geochemical composition of the horizons was studied. The effect of human activities on the soil was investigated as well as the geographical origin of Mancha wines. It was found that these activities did not give rise to significant variations of trace elements, although a discontinuity related to the accumulation of new materials was detected. Ultimately, using established productivity standards, suitability for the cultivation of vines on these soils was determined.  相似文献   
77.
The aim of this paper is to presents a progress report on how a subnational jurisdiction, the Australian state of Victoria, is attempting to implement regional governance for sustainability through its catchment planning framework. The paper examines the lessons learnt from a best practice approach to the implementation of network governance to see whether there are actions that can be taken to improve regional governance for sustainability in Victoria. The authors argue that Victoria is implementing a network governance approach to natural resource management (NRM) as a significant component of sustainability and that this has certain advantages. In particular the emergence of Regional Catchment Strategies developed by the State's ten statutory Catchment Management Authorities as 'regional sustainability blueprints' is bringing a significant level of maturity to the state's governance framework. Furthermore the state is currently working to complete its governance for sustainability through new statewide integrating frameworks—an Environmental Sustainability Framework as well as a statewide Catchment Management and Investment Framework. The paper concludes that taking a network governance approach could have transformative potential but there are significant challenges ahead: the complex task of aligning of national, state, catchment and local government strategies through an outcomes focus; the scarcity of mechanisms and tools to assist in translation of strategies into integrated investment priorities; gaps in knowledge and understanding of natural resource management problems; limitations in the capacity of regional and local bodies, including local government; and getting the policy tools right within the framework. However, as the best practice examples illustrate, taking a gradual approach to the development of the institutions—building on successive wins in capacity—is the best and only way to proceed.  相似文献   
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本文总结了在尼泊尔珠穆朗玛峰国家公园所做的旅游影响的研究结果,调查了旅游利用和环境特点对步行道的影响.7条步行道分成208个路段,评估的总长度为90km.采用了4级评估体系对步行道的路况进行评价,用Arc/Info和Arc/View地理信息系统(GIS)对旅游利用影响的空间格局进行分析.研究表明旅游利用和道路破坏之间密切相关,但步行道位置和环境因素是同等重要的变量.本研究认为较系统、实验性的研究是必要的,这些工作能够将人类活动导致的步行道损坏和自然因素影响明确地区别开.  相似文献   
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