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Tsunamis have occurred in Canada due to earthquakes, landslides, and a large chemical explosion. The Pacific coast is at greatest risk from tsunamis because of the high incidence of earthquakes and landslides in that region. The most destructive historical tsunamis, however, have been in Atlantic Canada – one in 1917 in Halifax Harbour, which was triggered by a catastrophic explosion on a munitions ship, and another in 1929 in Newfoundland, caused by an earthquake-triggered landslide at the edge of the Grand Banks. The tsunami risk along Canada's Arctic coast and along the shores of the Great Lakes is low in comparison to that of the Pacific and Atlantic coasts. Public awareness of tsunami hazard and risk in Canada is low because destructive tsunamis are rare events. 相似文献
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Ethanol Production: Energy and Economic Issues Related to U.S. and Brazilian Sugarcane 总被引：1，自引：0，他引：1
For a thorough and up-to-date evaluation of all the fossil energy costs of ethanol production from sugarcane in both the U.S.
and Brazil, every energy input in the biomass production and ultimate conversion process must be included. In this study,
more than 12 energy inputs in average U.S. and Brazilian sugarcane production are evaluated. Then in the fermentation/distillation
operation, nine more fossil fuel inputs are identified and included. Some energy and economic credits are given for the bagasse
to reduce the energy inputs required for steam and electricity. Based on all the fossil energy inputs in U.S. sugarcane conversion
process, a total of 1.12 kcal of ethanol is produced per 1 kcal of fossil energy expended. In Brazil a total of 1.38 kcal
of ethanol is produced per 1 kcal of fossil energy expended. Some pro-ethanol investigators have overlooked various energy
inputs in U.S. and Brazilian sugarcane production, including farm labor, farm machinery, processing machinery, and others.
In other studies, unrealistic low energy costs were attributed to such energy inputs, as nitrogen fertilizer, insecticides,
and herbicides. Both the U.S. and Brazil heavily subsidize ethanol production. Thus billions of dollars are invested in subsidies
and this significantly increases the costs to the consumers. The environmental costs associated with producing ethanol in
the U.S. and Brazil are significant but have been generally overlooked. The negative environmental impacts on the availability
of cropland and freshwater, as well as on air pollution and public health, have yet to be carefully assessed. These environmental
costs in terms of energy and economics should be calculated and included in future ethanol analyses so that sound assessments
can be made. In addition, the production of ethanol in the U.S. and Brazil further confirms that the mission of converting
biomass into ethanol will not replace oil. This mission is impossible. General concern has been expressed about taking food
crops to produce ethanol for burning in automobiles instead of using these crops as food for the many malnourished people
in the world. The World Health Organization reports that more than 3.7 billion humans are currently malnourished in the world—the
largest number of malnourished ever in history. 相似文献
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Data from Mesoamerican studies shows that the proportion of women registered as ‘farm operators’ in fairtrade-organic coffee producer unions has increased significantly. However, this increase is uneven across Mesoamerican communities and the prospects for improved gender equity rest on several questions that we explore in this study. First, what explains the large discrepancies in participation across groups? Second, what effect does the ‘farm operator’ status have on women’s ability to participate in producer unions and in fairtrade-organic coffee networks? Third, how will fairtrade-organic organizational and procedural norms affect women’s insertion into the coffee ‘value-chain’? Making use of ethnographic, archival, and survey data we find that fairtrade organizational norms combine with organic procedural norms to bring significant impacts in three areas: women’s organizations have greater access to network benefits, women gain greater control over farm practices, and women enjoy increased access to cash. However, we also find that the burden of complying with norms together with stagnant real prices excludes some women who might otherwise benefit from expanded participation. 相似文献
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The problem of storm surges is introduced briefly. The utility of passive microwave observations to study this phenomenon is pointed out. The reasons for the nonoccurrence of severe surges in the Bay of Bengal, during monsoon regimes, is discussed in this paper. It was demonstrated that the predominant reason for lack of severe surges over the Bay of Bengal coast is due to the absence of weak wind shear during monsoon seasons.Atmospheric Environment Service, Ice Center, Environment Canada, 373 Sussex Drive, Ottawa, Ontario, Canada K1A OH3. 相似文献
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Thomas C. Beard Christopher J. Perry Tad C. Fox Thomas G. Naymik Peter Shanahan 《Environmental Geology》1991,18(3):195-207
The regulatory requirements for characterization of the Martinsville Alternative Site (MAS) were fulfilled by applying an iterative approach to the groundwater flow modeling of the site and surrounding area. The approach consisted of field data collection and development of an initial conceptual model. The numerical model was then constructed to be consistent with the data and conceptual model. Next, the calibration results were evaluated statistically, and visually by a groundwater modeling review committee, to determine if the model accurately represented groundwater flow at the site. Initial results failed acceptance criteria because the values of numerical model input parameters had to be varied beyond observed data ranges to calibrate the results, and therefore the model was inconsistent with the initial conceptual model. This led to additional field data collection in areas where the numerical model deviated most from field-determined data. The new data provided sufficient information to revise the conceptual model and calibrate the numerical model successfully. Model calibration was followed by validation. Validation of the numerical model provided additional assurance that the model correctly simulated the observed system. No additional data were found to be necessary during validation of the MAS numerical model. The iterative approach proved to be successful for calibrating and validating this groundwater flow model and should be implemented from the onset of characterization planning in other applications. 相似文献
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