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Applications of Artificial Intelligence, particularly Expert Systems, are rapidly increasing. This science promises to give computer-based systems the capability of reasoning and decision making in near human-like fashion. Whether used for farm management or intelligent machine control, Expert Systems will find many agricultural applications. Much of the development and distribution of such systems will probably take place in the public sector, particularly the Cooperative Extension Service. A major nontechnical factor affecting the development and extensive use of Expert Systems is the legal issue of products, liability, and negligence. The legal issues surrounding Expert Systems have not yet been fully tested and defined by the courts. Developers and users of Expert Systems must consider these factors for each particular application. 相似文献
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Seymour Colleen L. Gillson Lindsey Child Matthew F. Tolley Krystal A. Curie Jock C. da Silva Jessica M. Alexander Graham J. Anderson Pippin Downs Colleen T. Egoh Benis N. Ehlers Smith David A. Ehlers Smith Yvette C. Esler Karen J. O’Farrell Patrick J. Skowno Andrew L. Suleman Essa Veldtman Ruan 《Ambio》2020,49(6):1211-1221
Ambio - A horizon scan was conducted to identify emerging and intensifying issues for biodiversity conservation in South Africa over the next 5–10 years. South African biodiversity... 相似文献
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Timothy J. Downs 《Journal of Environmental Planning and Management》2000,43(5):601-621
Complex relationships exist between human nature and needs, cultural evolution and ecological dynamics. The purpose of this paper is to present a working hypothesis that explores how we may reverse worsening underdevelopment, poverty and unsustainability trends world-wide. Empirical evidence from cultural history and contemporary project experience are used to suggest a development process that combines three critical dimensions: ethics, productive social interaction and knowledge integration. Logic dictates that the process should be applied in any given country to mobilize investment in supplies of natural, human and economic capital, principally biodiversity, soil and water conservation, education and public health. A sociopolitical theory of underdevelopment is presented to suggest that unethical virtual cartels control social interaction, knowledge integration and resource mobilization, precipitating negative feedback effects on human development, ecological stability and, ultimately, cultural evolution. The hypothesis was formulated using observations over 5 years in Mexico and case-study experience to initiate an alternative process of water resource conservation. 相似文献
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A numerical model was developed to describe the fate and transport of hydrazinium (N2H5+) and competing Ca2+ and H+ cations applied in acidic solutions to columns of Ca2+/H+-saturated sandy soil during steady saturated flow conditions. Instantaneous ternary H+-Ca2+-N2H5+ cation exchange using the Gaines-Thomas approach was combined with second-order, irreversible, kinetic chemisorption of exchange-phase N2H5+ ions as major retention mechanisms for N2H5+. Exchange-mediated chemisorption is assumed to occur as chemical binding of N2H5+ ions located on carboxyl-group exchange sites to nearby carbonyl groups, consequently decreasing the effective soil cation exchange capacity (CEC). Comparison of simulated and observed breakthrough curves (BTCs) for concentrations of N2H5+ and Ca2+ ions in column effluent was used in model evaluation. The cation transport model with cation exchange coupled with exchange-mediated chemisorption provided a valid first approximation for N2H5+ transport. 相似文献
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Downs PW Singer MS Orr BK Diggory ZE Church TC Stella JC 《Environmental management》2011,48(4):847-864
The goal of restoring ecological integrity in rivers is frequently accompanied by an assumption that a comparative reference
reach can be identified to represent minimally impaired conditions. However, in many regulated rivers, no credible historical,
morphological or process-based reference reach exists. Resilient restoration designs should instead be framed around naturalization,
using multiple analytical references derived from empirically-calibrated field- and model-based techniques to develop an integrated
ecological reference condition. This requires baseline data which are rarely collected despite increasing evidence for systematic
deficiencies in restoration practice. We illustrate the utility of baseline data collection in restoration planning for the
highly fragmented and regulated lower Merced River, California, USA. The restoration design was developed using various baseline
data surveys, monitoring, and modeling within an adaptive management framework. Baseline data assisted in transforming conceptual
models of ecosystem function into specific restoration challenges, defining analytical references of the expected relationships
among ecological parameters required for restoration, and specifying performance criteria for post-project monitoring and
evaluation. In this way the study is an example of process-based morphological restoration designed to prompt recovery of
ecosystem processes and resilience. For the Merced River, we illustrate that project-specific baseline data collection is
a necessary precursor in developing performance-based restoration designs and addressing scale-related uncertainties, such
as whether periodic gravel augmentation will sustain bed recovery and whether piecemeal efforts will improve ecological integrity.
Given the numerous impediments to full, historical, restoration in many river systems, it seems apparent that projects of
naturalization are a critical step in reducing the deleterious impacts of fragmented rivers worldwide. 相似文献
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A Method for Spatially Explicit Representation of Sub-watershed Sediment Yield,Southern California,USA 总被引:1,自引:0,他引:1
Derek B. Booth Glen Leverich Peter W. Downs Scott Dusterhoff Sebastian Araya 《Environmental management》2014,53(5):968-984
We present here a method to integrate geologic, topographic, and land-cover data in a geographic information system to provide a fine-scale, spatially explicit prediction of sediment yield to support management applications. The method is fundamentally qualitative but can be quantified using preexisting sediment-yield data, where available, to verify predictions using other independent data sets. In the 674-km2 Sespe Creek watershed of southern California, 30 unique “geomorphic landscape units” (GLUs, defined by relatively homogenous areas of geology, hillslope gradient, and land cover) provide a framework for discriminating relative rates of sediment yield across this landscape. Field observations define three broad groupings of GLUs that are well-associated with types, relative magnitudes, and rates of erosion processes. These relative rates were then quantified using sediment-removal data from nearby debris basins, which allow relatively low-precision but robust calculations of both local and whole-watershed sediment yields, based on the key assumption that minimal sediment storage throughout most of the watershed supports near-equivalency of long-term rates of hillslope sediment production and watershed sediment yield. The accuracy of these calculations can be independently assessed using geologically inferred uplift rates and integrated suspended sediment measurements from mainstem Sespe Creek, which indicate watershed-averaged erosion rates between about 0.6–1.0 mm year?1 and corresponding sediment yields of about 2 × 103 t km?2 year?1. A spatially explicit representation of sediment production is particularly useful in a region where wildfires, rapid urban development, and the downstream delivery of upstream sediment loads are critical drivers of both geomorphic processes and land-use management. 相似文献