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991.
Community-based monitoring (CBM) activities in Canada are increasing. A conceptual framework developed for and used to guide a pilot CBM project in 31 Canadian communities is evaluated. The framework provided the strategic direction necessary for successful implementation of the pilot and proved useful in the training of community coordinators hired for the project. Limitations of the framework include its inadequate attention to community diversity, its linearity, and insufficient expression of the adaptive and synergistic nature of its components. In order to support local sustainability, CBM appears to require an approach that is context-specific, iterative, and adaptive. Given these emergent characteristics, an enhanced conceptual framework for CBM in Canada is developed based on four dynamic themes: community mapping, participation assessment, capacity building, and information delivery. 相似文献
992.
Public Perception of Flood Hazard in the Niger Delta,Nigeria 总被引:3,自引:0,他引:3
Summary Our study had the aim of understanding how floodplain dwellers regard the risk of flooding. About 500 questionnaires were
administered to landowners in the selected settlements in the study area using systematic random sampling. The results of
analysis show, among other things, that the population regards most important the causes of floods as heavy, prolonged rainfall
and river overflow. Nevertheless, they have little knowledge of the frequency of severe floods, and flood alleviation schemes.
Most flood victims do not get compensation or relief during flood disaster, and the reason why they remain in the study area
is influenced by their occupations, especially fishing, subsistence agriculture, and the presence of crude oil in the region
which has attracted many migrants who cannot afford the high cost of accommodation and are therefore forced to live in vulnerable
areas of the floodplain. Finally, the study concludes that flood control in the region needs the cooperation of government,
community efforts and an enlightenment programmes through environmental education and mass media. 相似文献
993.
Loss of grassland species resulting from activities such as off-road vehicle use increases the need for models that predict
effects of anthropogenic disturbance. The relationship of disturbance by military training to plant species richness and composition
on two soils (Foard and Lawton) in a mixed prairie area was investigated. Track cover (cover of vehicle disturbance to the
soil) and soil organic carbon were selected as measures of short- and long-term disturbance, respectively. Soil and vegetation
data, collected in 1-m2 quadrats, were analyzed at three spatial scales (60, 10, and 1 m2). Plant species richness peaked at intermediate levels of soil organic carbon at the 10-m2 and 1-m2 spatial scales on both the Lawton and Foard soils, and at intermediate levels of track cover at all three spatial scales
on the Foard soil. Species composition differed across the disturbance gradient on the Foard soil but not on the Lawton soil.
Disturbance increased total plant species richness on the Foard soil. The authors conclude that disturbance up to intermediate
levels can be used to maintain biodiversity by enriching the plant species pool. 相似文献
994.
995.
A. Wieraszko Z. Ahmed J. Armani N. Maqsood S. Philips H. Raja 《The Environmentalist》2005,25(2-4):145-155
Summary The influence of pulsed magnetic fields (PMF) on the properties of nervous tissue was investigated. Hippocampal slices or
synaptosomes obtained from hippocampal tissue were used as model systems. The amplitude of potentials recorded in vitro from one of the hippocampal pathways (Schaffer collaterals that use glutamate as a neurotransmitter) was employed as a measure
of the influence of magnetic fields on synaptic efficiency. The synaptic glutamate turnover and radioactive calcium accumulation
were used as markers of the PMF influence on biochemistry of synaptic mechanisms. The exposure of hippocampal slices for 30
min to PMF amplified evoked potentials. While the frequency of 0.16 Hz exerted the strongest effect, lower (0.01, 0.07, 0.03
Hz) and higher (0.5 Hz) frequencies were much less effective. The enhancement of the neuronal excitability was correlated
with significant increase in the neuronal spontaneous activity mediated by electrical synapses. The PMF-induced changes in
the excitability of the tissue were accompanied by an increase in the synaptic turnover of glutamate. The release of radioactive
D-Aspartate (a glutamate analog used as a marker for glutamate turnover) from the slices, and its uptake by synaptosomes were
enhanced, and reduced respectively, following the stimulation with pulsed magnetic fields. The frequency which was the most
efficient in amplification of evoked potentials (0.16 Hz) was also the most effective in the modulation of the release and
uptake processes. The PMF-induced changes in neurotransmitter turnover coincided with an increase in 45Ca2+ accumulation observed in hippocampal slices exposed to PMF. 相似文献
996.
Summary The balance of evidence suggests a perceptible human influence on global ecosystems. Human activities are affecting the global
ecosystem, some directly and some indirectly. If researchers could clarify the extent to which specific human activities affect
global ecosystems, they would be in a much better position to suggest strategies for mitigating against the worst disturbances.
Sophisticated statistical analysis can help in interpreting the influence of specific human activities on global ecosystems
more carefully. This study aims at identifying significant or influential human activities (i.e. factors) on CO2 emissions using statistical analyses. The study was conducted for two cases: (i) developed countries and (ii) developing
countries. In developed countries, this study identified three influential human activities for CO2 emissions: (i) combustion of fossil fuels, (ii) population pressure on natural and terrestrial ecosystems, and (iii) land
use change. In developing countries, the significant human activities causing an upsurge of CO2 emissions are: (i) combustion of fossil fuels, (ii) terrestrial ecosystem strength and (iii) land use change. Among these
factors, combustion of fossil fuels is the most influential human activity for CO2 emissions both in developed and developing countries. Regression analysis based on the factor scores indicated that combustion
of fossil fuels has significant positive influence on CO2 emissions in both developed and developing countries. Terrestrial ecosystem strength has a significant negative influence
on CO2 emissions. Land use change and CO2 emissions are positively related, although regression analysis showed that the influence of land use change on CO2 emissions was still insignificant. It is anticipated, from the findings of this study, that CO2 emissions can be reduced by reducing fossil-fuel consumption and switching to alternative energy sources, preserving exiting
forests, planting trees on abandoned and degraded forest lands, or by planting trees by social/agroforestry on agricultural
lands. 相似文献
997.
The Ethics of Constrained Choice: How the Industrialization of Agriculture Impacts Farming and Farmer Behavior 总被引:3,自引:0,他引:3
Mary?K.?HendricksonEmail author Harvey?S.?James 《Journal of Agricultural and Environmental Ethics》2005,18(3):269-291
The industrialization of agriculture not only alters the ways in which agricultural production occurs, but it also impacts the decisions farmers make in important ways. First, constraints created by the economic environment of farming limit what options a farmer has available to him. Second, because of the industrialization of agriculture and the resulting economic pressures it creates for farmers, the fact that decisions are constrained creates new ethical challenges for farmers. Having fewer options when faced with severe economic pressures is a very different situation for farmers than having many options available. We discuss the implications of constrained choice and show that it increases the likelihood that farmers will consider unethical behavior. 相似文献
998.
999.
Recent research has focused on establishing the values of preserving biodiversity both in agriculture and in less managed ecosystems, and in showing the importance of the role of cultural diversity in preserving biodiversity in food production systems. A study of the philosophy embedded in cultural systems can reveal the importance of the technological information for preserving genetic biodiversity contained in such systems and can be used to support arguments for the protection/preservation of cultural diversity. For example, corn or maize can serve as a paradigm of Native American thinking and can provide one of the few areas from which common philosophical conceptions can emerge. An examination of the cultivation of corn or maize as an agricultural activity and as a cultural activity in Native American literature reveals a philosophy that recognizes the importance of biodiversity and provides techniques for its preservation. Corn, and the food and the materials derived from it, is something thought out, not by specialists, but by the entire tribe and its ancestors, even if this thinking is done within what we might consider a framework of highly mythical notions. Importantly, this framework yields an understanding of both the genetics and nutrition of corn. A survey of these mythical notions (myths and stories) and agricultural practices makes this thought explicit and exemplifies the value of cultural diversity and biodiversity. 相似文献
1000.
Gaverick?Matheny Kai?M.?A.?ChanEmail author 《Journal of Agricultural and Environmental Ethics》2005,18(6):579-594
Few moral arguments have been made against vegetarian diets. One exception is the “Logic of the Larder:” We do animals a favor
by purchasing their meat, eggs, and milk, for if we did not purchase these products, fewer animals would exist. This argument
fails because many farm animals have lives that are probably not worth living, while others prevent a significant number of
wild animals from existing. Even if this were not so, the purchase of animal products uses resources that could otherwise
be used to bring a much greater number of animals into existence. 相似文献