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911.
912.
An essential step in the development of products based on biotechnology is an assessment of their potential economic impacts and safety, including an evaluation of the potential impact of transgenic crops and practices related to their cultivation on the environment and human or animal health. The purpose of this paper is to provide an assessment method to evaluate the impact of biotechnologies that uses quantifiable parameters and allows a comparative analysis between conventional technology and technologies using GMOs. This paper introduces a method to perform an impact analysis associated with the commercial release and use of genetically modified plants, the Assessment System GMP Method. The assessment is performed through indicators that are arranged according to their dimension criterion likewise: environmental, economic, social, capability and institutional approach. To perform an accurate evaluation of the GMP specific indicators related to genetic modification are grouped in common fields: genetic insert features, GM plant features, gene flow, food/feed field, introduction of the GMP, unexpected occurrences and specific indicators. The novelty is the possibility to include specific parameters to the biotechnology under assessment. In this case by case analysis the factors of moderation and the indexes are parameterized to perform an available assessment.  相似文献   
913.
RaMCo is a prototype version of a decision-support system for coastal-zone management. The model is based on the findings of a multidisiciplinary research program, conducted in Southwest Sulawesi, Indonesia. Different management strategies can be compared on the basis of the short- and long-term consequences. Land-use change has been included in RaMCo in view of the impacts of land-based human activities on the marine environment. The key aspect of the model is a combination of the temporal dynamics of land-use change on the regional (macro-level) scale and spatial dynamics on the local (micro-level) scale. Constrained cellular automata are used to integrate both scale levels. The state changes of the cells depend on the consistency with the macro-scale model, local geographical conditions, and interaction with neighboring cells. In this paper, we discuss the underlying theoretical assumptions of the macro-scale and micro-scale models, some characteristic results for land-use change in the study area, and the validation problem.  相似文献   
914.
915.
The Funil Reservoir (Rio de Janeiro State, Brazil) is an environment degraded by constant discharge of nutrients and pollution coming from the most industrialized region of the country. As a consequence of eutrophication, there are continuous cyanobacteria blooms, which cause acute and chronic toxicity to zooplankton. In this context, Phase I of Toxicity Identification Evaluation (TIE) was performed on Daphnia similis using water and interstitial water from the reservoir, with the aim of identifying classes of compounds responsible for toxicity. The results indicated that water toxicity was due to cyanobacteria resulting from blooms in the reservoir and surfactants. Metals, especially copper, contributed to sediment toxicity. This research is the first attempt to describe the nature of toxicity in this reservoir using this method.  相似文献   
916.
917.
In an effort to accurately assess national methane (CH4) production levels, many African countries are producing inventories of their national livestock populations. Conducting accurate livestock surveys is an expensive and time-consuming process, but is necessary because the most readily available data on livestock production are often incomplete or unsatisfactory. This paper looks at practical approaches to collecting data on livestock production and on the reproductive parameters for livestock, with special reference to African pastoralist populations, and makes qualified recommendations as to how inventory teams might be able to produce more accurate assessments of their total livestock populations. The methodology used during Nigeria's National Livestock Census (1990–92) serves as a basis for a discussion of the issues.  相似文献   
918.
Several mutagenic agents may be present in substances released in the environment, which may cause serious environmental impacts. Among these substances, there is a special concern regarding the widespread use of silver nanoparticles (AgNP) in several products due to their widely known bactericidal properties, including in the medical field and the food industry (e.g., active packaging). The assessment of the effects of AgNP released in the environment, having different concentrations, sizes, and being associated or not to other types of materials, including polymers, is therefore essential. In this research, the objective was to evaluate the genotoxic and cytotoxic effects of AgNP (size range between 2 and 8 nm) on root meristematic cells of Allium cepa (A. cepa). Tests were carried out in the presence of colloidal solution of AgNP and AgNP mixed with carboxymethylcellulose (CMC), using distinct concentrations of AgNP. As a result, when compared to control samples, AgNP induced a mitotic index decrease and an increase of chromosomal aberration number for two studied concentrations. When AgNP was in the presence of CMC, no cytotoxic potential was verified, but only the genotoxic potential for AgNP dispersion having concentration of 12.4 ppm.  相似文献   
919.
The maintenance of limnological monitoring programs in the Cerrado Domain is crucial as a provision of useful information about temporal variations in land use and their respective water quality responses, considering its importance as water source for different Brazilian hydrographic basins. The purpose of this research was to describe limnological variables of low-order lotic systems located in the Cerrado Long Term Ecological Research (LTER) site (Environmental Protection Area (APA) Gama and Cabeça de Veado, Federal District of Brazil). Altogether, nine different streams were considered in this study. Samplings were conducted between 2010 and 2012, concentrated in the dry and rainy seasons. The sampling sites were generally characterized by low nutrient concentrations (e.g., medians, TP?=?14.8 μg L?1, TN?=?20.0 μg L?1, NO3?=?13.8 μg L?1) and slightly acidic waters (median, pH?=?5.3), with quite low electrical conductivity values (median?=?6.4 μS cm?1). However, water quality degradation as a response to diffuse pollution was reported in some sampling points (e.g., Onça and Gama streams), expressed by relatively higher N and P concentrations, which were probably highlighted by the good water quality of the data set as whole. Although there was a trend to higher values of nitrogen forms during the dry season, significant statistical differences between the seasonal periods were reported only for the variables temperature and dissolved silica, which were higher in the dry and rainy season, respectively. The streams located in the preserved areas inside the ecological stations of APA Gama and Cabeça de Veado can still be considered good examples of reference lotic systems in the Cerrado Domain; notwithstanding, this study reported incipient signs of water quality degradation which cannot be overlooked in future limnological monitoring.  相似文献   
920.
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