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51.
Abu T. Khan Thomas C. Graham L. Ogden S. Ali Salwa Sherylee J. Thompson 《Journal of environmental science and health. Part. B》2013,48(4):403-415
A two-generation reproductive toxicity study of zinc chloride (ZnCl2) was conducted in rats. Fo male and female rats were administered 0.00 (control), 7.50 (low), 15.00 (mid) and 30.00 (high) mg/kg/day of ZnCl2. Selected F1 male and female rats were exposed to the same doses received by their parents (Fo). Exposure of F0 parental rats to ZnCl2 showed significant reduction in fertility, viability (days 0 and 4), and the body weight of F1 pups from the high-dose group but caused no effects on litter size, weaning index, and sex ratio. Similarly, the continued exposure of F1 parental rats to ZnCl2 also reduced fertility, liter size, viability (day 0), and the body weight of F2 pups within the high-dose group but caused no effects on weaning index and sex ratio. Exposure of ZnCl2 to F0 and F1 parental males resulted in a significant reduction in their body weights, and the F0 and F1 parental females did not show any significant difference in their body weights compared to their control groups. However, the postpartum dam weights of both F0 and F1 female rats were significantly reduced compared to their controls. Exposure of ZnCl2 to Fo and F1 generation parental rats did not produce any significant change of their clinical signs as well as their clinical pathology parameters, except the alkaline phosphotase (ALK) level, which showed an upward trend in both sexes of both generations. Exposure of ZnCl2 to F0 rats resulted in a reduction of brain, liver, kidney, spleen and seminal vesicles weights of males and in the spleen and uterus of females. Similarly, exposure of F1 rats to ZnCl2 also resulted in reduction of brain, liver, kidney, adrenal, spleen, prostate and seminal vesicles weights of males and in spleen and uterus of females. ZnCl2 exposure resulted in grossly observed gastro-intestianla (GI) tract, lymphoreticular/hematopoietic, and reproductive tract lesions in parental rats in both generations. Reduced body fat was also recorded in F1 parental rats. 相似文献
52.
Jaques Reifman Earl E. Feldman Thomas Y.C. Wei Roger W. Glickert 《Journal of the Air & Waste Management Association (1995)》2013,63(2):240-251
ABSTRACT The application of artificial intelligence techniques for performance optimization of the fuel lean gas reburn (FLGR) system is investigated. A multilayer, feedforward artificial neural network is applied to model static nonlinear relationships between the distribution of injected natural gas into the upper region of the furnace of a coal-fired boiler and the corresponding oxides of nitrogen (NOx) emissions exiting the furnace. Based on this model, optimal distributions of injected gas are determined such that the largest NOx reduction is achieved for each value of total injected gas. This optimization is accomplished through the development of a new optimization method based on neural networks. This new optimal control algorithm, which can be used as an alternative generic tool for solving multidimensional nonlinear constrained optimization problems, is described and its results are successfully validated against an off-the-shelf tool for solving mathematical programming problems. Encouraging results obtained using plant data from one of Commonwealth Edison's coal-fired electric power plants demonstrate the feasibility of the overall approach. Preliminary results show that the use of this intelligent controller will also enable the determination of the most cost-effective operating conditions of the FLGR system by considering, along with the optimal distribution of the injected gas, the cost differential between natural gas and coal and the open-market price of NOx emission credits. Further study, however, is necessary, including the construction of a more comprehensive database, needed to develop high-fidelity process models and to add carbon monoxide (CO) emissions to the model of the gas reburn system. 相似文献
53.
Simulating Land-Cover Change in Montane Mainland Southeast Asia 总被引:6,自引:0,他引:6
We used the conversion of land use and its effects (CLUE-s) model to simulate scenarios of land-cover change in Montane mainland
southeast Asia (MMSEA), a region in the midst of transformation due to rapid intensification of agriculture and expansion
of regional trade markets. Simulated changes affected approximately 10 % of the MMSEA landscape between 2001 and 2025 and
16 % between 2001 and 2050. Roughly 9 % of the current vegetation, which consists of native species of trees, shrubs, and
grasses, is projected to be replaced by tree plantations, tea, and other evergreen shrubs during the 50 years period. Importantly,
4 % of this transition is expected to be due to the expansion of rubber (Hevea brasiliensis), a tree plantation crop that may have important implications for local-to-regional scale hydrology because of its potentially
high water consumption in the dry season. 相似文献
54.
Thomas Seager Evan Selinger Arnim Wiek 《Journal of Agricultural and Environmental Ethics》2012,25(4):467-484
Because wicked problems are beyond the scope of normal, industrial-age engineering science, sustainability problems will require reform of current engineering science and technology practices. We assert that, while pluralism concerning use of the term sustainability is likely to persist, universities should continue to cultivate research and education programs specifically devoted to sustainable engineering science, an enterprise that is formally demarcated from business-as-usual and systems optimization approaches. Advancing sustainable engineering science requires a shift in orientation away from reductionism and intellectual specialization towards integrative approaches to science, education, and technology that: (1) draw upon an ethical awareness that extends beyond the usual bounds of professional ethics or responsible conduct of research to include macroethics, (2) adopt anticipatory and adaptive approaches to unintended consequences resulting from technological innovation that result in more resilient systems, and (3) cultivate interactional expertise to facilitate cross-disciplinary exchange. Unfortunately, existing education and research training programs are ill-equipped to prepare scientists and engineers to operate effectively in a wicked problems milieu. Therefore, it is essential to create new programs of graduate education that will train scientists and engineers to become sustainable engineering science experts equipped to recognize and grapple with the macro-ethical, adaptive, and cross-disciplinary challenges embedded in their technical research and development programs. 相似文献
55.
Stabilizing global greenhouse gas concentrations at levels to avoid significant climate risks will require massive "decarbonization" of all the major economies over the next few decades, in addition to the reduced emissions from other GHGs and carbon sequestration. Achieving the necessary scale of emissions reductions will require a multifaceted policy effort to support a broad array of technological and behavioral changes. Change on this scale will require sound, well-thought-out strategies. In this article, we outline some core principles, drawn from recent social science research, for guiding the design of clean technology policies, with a focus on energy. The market should be encouraged to make good choices: pricing carbon emissions and other environmental damage, removing distorting subsidies and barriers to competition, and supporting RD&D broadly. More specific policies are required to address particular market failures and barriers. For those technologies identified as being particularly desirable, some narrower RD&D policies are available. 相似文献
56.
Thomas WH 《Environmental management》2010,45(1):82-92
It has been proposed that indigenous societies can be models for the conservation of biodiversity. However, attempts at implementing
conservation-based development plans are being judged failures. In this article, I argue that these failures can be addressed
by translating indigenous knowledge into context that is mutually intelligible to both indigenous people and conservation
biologists. Drawing on sixteen months of ethnobiological fieldwork, this article uses indigenous knowledge to describe the
relationship of traditional life to biodiversity for the Hewa of Papua New Guinea’s Central Range. The island of New Guinea
is one of the planet’s last bastions of cultural and biological diversity. Using birds as an indicator of diversity, I argue
that more productive conservation policies will emerge when indigenous activities are viewed not as vehicles for establishing
equilibrium with the environment, but as a source of ecological disturbance. Although Hewa traditions currently play a significant
role in shaping this biologically diverse environment, their lifestyle is not necessarily a template for sustainability in
the future. 相似文献
57.
The radon isotope 222Rn and salinity in coastal surface water were mapped on regional scales, to improve the understanding of coastal processes and their spatial variability. Radon was measured with a surface-towed, continuously recording multi-detector setup on a moving vessel. Numerous processes and locations of land-ocean interaction along the Central Great Barrier Reef coastline were identified and interpreted based on the data collected. These included riverine fluxes, terrestrially-derived fresh submarine groundwater discharge (SGD) and the tidal pumping of seawater through mangrove forests. Based on variations in the relationship of the tracers radon and salinity, some aspects of regional freshwater inputs to the coastal zone and to estuaries could be assessed. Concurrent mapping of radon and salinity allowed an efficient qualitative assessment of land-ocean interaction on various spatial and temporal scales, indicating that such surveys on coastal scales can be a useful tool to obtain an overview of SGD locations and processes. 相似文献
58.
The current trend in foreign aid is toward small-scale sustainable development projects in partnership with defined communities.
However, these projects are subject to the influences of self-interested human behavior, poorly defined community structures
and resources and organizational constraints that can prevent full realization of development models. Under these constraints,
attempting participatory community development models to the exclusion of other techniques may not be the most effective way
to achieve positive change. Instead, development agencies should consider adopting other proven elements of development in
combination with the spirit of community development to achieve a positive impact within the community and organizational
structures and ensure accountability for success. A small-scale attempted, sustainable development case study in Rwanda is
reviewed, as well as a new concept for larger scale development integrating ‘carbon credits’. Additionally, a development
accreditation organization is proposed to ensure additional accountability in this field. 相似文献
59.
Bernadette Teufl Gabriele Weigelhofer Jennifer Fuchsberger Thomas Hein 《Environmental science and pollution research international》2013,20(3):1781-1793
Intensive agricultural land use imposes multiple pressures on streams. More specifically, the loading of streams with nutrient-enriched soil from surrounding crop fields may deteriorate the sediment quality. The current study aimed to find out whether stream restoration may be an effective tool to improve the sediment quality of agricultural headwater streams. We compared nine stream reaches representing different morphological types (forested meandering reaches vs. deforested channelized reaches) regarding sediment structure, sedimentary nutrient and organic matter concentrations, and benthic microbial respiration. Main differences among reach types were found in grain sizes. Meandering reaches featured larger mean grain sizes (50–70 μm) and a thicker oxygenated surface layer (8 cm) than channelized reaches (40 μm, 5 cm). Total phosphorous amounted for up to 1,500 μg?g?1 DW at retentive channelized reaches and 850–1,050 μg?g?1 DW at the others. While N-NH4 accumulated in the sediments (60–180 μg?g?1 DW), N-NO3 concentrations were generally low (2–5 μg?g?1 DW). Benthic respiration was high at all sites (10–20 g O2 m?2?day?1). Our study shows that both hydromorphology and bank vegetation may influence the sediment quality of agricultural streams, though effects are often small and spatially restricted. To increase the efficiency of stream restoration in agricultural landscapes, nutrient and sediment delivery to stream channels need to be minimized by mitigating soil erosion in the catchment. 相似文献
60.
H. P. Sanderson R. Thomas Morris Katz 《Journal of the Air & Waste Management Association (1995)》2013,63(6):328-330
Field experience with the lead acetate impregnated paper tape sampler has indicated that large errors may arise in this method due to fading of the color of the precipitated lead sulfide spots. This fading is due to the action of light, sulfur dioxide, ozone, on other substances capable of oxidizing lead sulfide. The moisture content or relative humidity of the air sample must be maintained at an appropriate level to ensure reaction with the impregnated paper tape. The effects of the factors have been investigated in laboratory experiments with known concentrations of H2S. A number of antioxidants were studied in relation to the stability of the resultant spots to light and oxidation Orthophenyl phenol was found to be the most effective antioxidant for this purpose. A number of necessary precautions to be employed in the use of the lead acetate method are recommended and the limitations are discussed. 相似文献