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The considerations involved in defining appropriate roles for the public and private sectors in agricultural research are examined with respect to mechanization, plant variety, and insecticide research and development. It is concluded that the public sector should continue to give mechanization a low priority. Varietal improvement should remain a relatively high priority until the effects of plant variety protection legislation become more apparent. Simultaneous achievement of safety, environmental, and productivity objectives in insect pest control will require that the public sector play a larger role in research and development.  相似文献   
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In this article we examine the economic benefits of the long history of public research in agriculture. Agricultural productivity continues to grow. Annual rates of return on research expenditure are of the order of 50 percent. Research oriented to science is profitable when associated with technological research. Decentralization, as in the system of state agricultural experiment stations and substations, has allowed close association of research oriented to science with that oriented to technology and to farming. The high rate of return shows that investment in public research in agriculture is too low. This is at least partially because research benefits spill over to other regions and to consumers, reducing the incentives for local support.  相似文献   
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Atomic absorption spectroscopy procedures are outlined for the determination of some important heavy metals in sewage treatment plant solids and liquids. Problems associated with sample preparation and sample solution interferences are described. It is recommended that reference standards and internal laboratory control samples be used to allow some assessment of the validity of results. Sewage treatment plant products both liquid and solid were analyzed and results given for samples representing a wide range of sewage input patterns.  相似文献   
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