Non-point sources and the waste discharge charge system.

The development of a waste discharge charge system (WDCS) in South Africa has been proposed to promote waste reduction and water conservation. The WDCS is based on the polluter pays principle and is designed such that the management of waste discharges achieves resource quality objectives (RQOs) at the minimum total cost to the catchment. Two charges are distinguished: first a charge for optimising use of the resource (incentive charge); and secondly, a charge for development and operation of mitigation measures in the resource (mitigation charge). The WDCS is applied to both point sources and non-point sources (NPS) of contamination. In the inclusion of NPS, the charge system distinguishes between registered and non-registered NPS, with the charge applied to the former group only, in the first instance. This paper introduces the WDCS by describing the principles and the theoretical basis of the WDCS, highlighting the link to RQOs as the benchmark of acceptable externalities. The paper explores the inclusion of NPS in the WDCS, describing: first, the principles of NPS inclusion in the WDCS; secondly, the types of NPS included in the present version of the WDCS; thirdly, the methodology for charge estimation; and finally, non-registered NPS and their potential inclusion in future editions of the WDCS. The paper concludes with remarks and challenges facing the first edition of the WDCS.     

New climate change scenarios for the Netherlands.

A new set of climate change scenarios for 2050 for the Netherlands was produced recently. The scenarios span a wide range of possible future climate conditions, and include climate variables that are of interest to a broad user community. The scenario values are constructed by combining output from an ensemble of recent General Climate Model (GCM) simulations, Regional Climate Model (RCM) output, meteorological observations and a touch of expert judgment. For temperature, precipitation, potential evaporation and wind four scenarios are constructed, encompassing ranges of both global mean temperature rise in 2050 and the strength of the response of the dominant atmospheric circulation in the area of interest to global warming. For this particular area, wintertime precipitation is seen to increase between 3.5 and 7% per degree global warming, but mean summertime precipitation shows opposite signs depending on the assumed response of the circulation regime. Annual maximum daily mean wind speed shows small changes compared to the observed (natural) variability of this variable. Sea level rise in the North Sea in 2100 ranges between 35 and 85 cm. Preliminary assessment of the impact of the new scenarios on water management and coastal defence policies indicate that particularly dry summer scenarios and increased intensity of extreme daily precipitation deserves additional attention in the near future.     

Calculating nitrogen-removal efficiency with a one-dimensional nitrogen budget model of a reed-wetland soil system.

A simple one-dimensional model that can evaluate the transport and fate of nitrogen in wetland soil-vegetation systems was developed to calculate the nitrogen-removal efficiencies of reed-bed wetlands. A common wetland plant, Phragmites australis, was the focus of this study. Seasonal variations of temperature, seasonal changes of nitrogen uptake by vegetation, the vertical distribution of root biomasses and oxygen transport into the soil by vegetation were considered in the model. Field observations were conducted to determine some model parameters and to validate the model, although most of the parameters were adopted from data published in Europe and North America. Field observations were carried out at the Minuma-Tanbo wetland (35 degrees 52' N, 139 degrees 43' E) in Japan. The calculated concentrations of NH4-N in the soils were about 10 times larger than those of the observational results. On the other hand, calculated NO3-N concentrations were about half of the observational data. However, the calculated nitrogen-removal efficiencies indicated the same trends as previous studies. It was found that the hydraulic loading rate played a key role in relation to nitrogen removal and nitrogen transformation in reed wetland systems.     

基于雅可比矩阵的电压控制区域划分的改进

对应用比较广泛的电压控制区域（VCA）划分方法进行了改进，在传统的去除小元素法基础上，采用牛顿 — 拉夫逊法潮流雅可比矩阵中有功和无功对电压幅值偏导数的子矩阵之和进行VCA划分;然后，将各种拓扑变化对系统电压稳定性的影响进行排序，按从大到小的顺序用这些拓扑变化对得到的VCA分区进行修正，直到修正结果不再改变为止，从而得到了适用于各种拓扑结构下电压稳定性分析的分区。改进后分区的有效性在新英格兰10机39节点系统上得到了验证。     

North-South interdependence: An economic-physical interpretation

Summary The article gives a physical-economic interpretation to a number of economic North-South interdependent relations. Basic research evidence at the man-machine level was an inspiration; the output could only be expressed in physical specification terms. The corresponding generalizations are in product complexity, speciality terms also. This terminology is conducive to far-ranging extrapolations and generalizations. It eliminates the problem of pricing at the product level for all aggregation levels; therefore the fundamental economic relations are better expressed. The article concludes with a mega extrapolation in graphical terms, which relates the product and implied technological capability in the world, expressed in physical terms, for country groups ordered by three development levels. Correspondingly the comparative advantage and inter-industry trade areas at the world product level are shown.The author acknowledges valid comments of two anonymous referees and financial support by DGIS to the Technology Scientific Foundation for the research of which this paper reports certain aspects only. This paper came out as a working paper TSF 84-1. An earlier version was presented at the International Economic Association Meeting in Madrid, Sept. 1983. Clearly, only the author bears responsibility for the ideas and interpretations presented in the following text.     

Diffuse pollution in Japan: issues and perspectives.

Many parts of Japan have experienced rapid urbanization and industrialization over the past 50 years. This trend resulted in severe water pollution in many urban areas. To address the pollution problems, several measures such as construction of sewerage systems and enactment of laws and regulations have been undertaken. Because of these measures, the water quality has been improved to some extent. However, many water quality concerns still remain and are attributed in part to diffuse pollution. In this paper, historical progress, present situation and future aspects of diffuse pollution problems in Japan are reviewed. It is noted that solving diffuse pollution problems will require a combination of several measures including application of conventional treatment technologies and natural purification systems, implementation of appropriate policy measures, and promotion of citizen participation.     

The Role Of Maternal Literacy in Reducing the Risk of Child Malnutrition in India

This study uses unit-record data on over 50,000 rural children, from the sixteen major states of India, to analyse the determinants of the risks of severe stunting and of being severely underweight. The importance of this study derives from the fact that the prevalence of under-nourishment in India is, even relative to other poor countries, shockingly high. The study focuses on the role of maternal literacy in reducing the risk of child malnourishment. It concludes that when the mother is literate, real benefits flow to children in terms of reduced risk; the same benefits, however, do not flow when the father, but not the mother, is literate. Literate mothers make more effective use of health-care institutions, like anganwadis and hospitals. Consequently, the benefits to children from expanding the supply of such institutions are greater when these institutions interact with mothers who are literate.