水力负荷与气水比对人工湿地净水效果的影响

以某高海拔地区污水处理厂的二级生化处理水为研究对象,通过对人工湿地进出水中COD、NH+4-N、TP浓度的变化,研究了水力负荷、气水比两个参数对人工湿地净水效果的影响。结果表明:人工湿地去除生活污水中COD、NH4+-N、TP的最佳水力负荷为0.33 m3/(m2·d)、气水比为3:1,在此最佳试验条件下,COD、NH4+-N、TP的去除率分别可达84%、69%、68%,出水水质满足《地表水环境质量标准》Ⅲ类水质标准。     

Modelling the spatial distribution of red grouper (Epinephelus morio) at Campeche Bank, México, with respect substrate

The red grouper (Epinephelus morio) has historically been one of the most important fisheries of the Campeche Bank area in the Gulf of México, where two fleets from México and one from Cuba participate. Current stocks have been estimated to be a third or less as abundant as in the 1970s; hence, the fishery has been declared to be over-exploited. The federal government of México has expressed the need to investigate the potential use of protected areas as a management tool for recovery of this species. Based on artificial neural network (ANN) modelling, we analysed the spatial distribution of red grouper with respect substrate, considering the demographic structure of the stock. We found a significant relationship between the type of substrate and the three stages of development (juveniles, pre-adults and adults). Juveniles are distributed in shallow waters close to the coast on coral substrates; pre-adults are also associated with coral substrates, but at an intermediate depth; adults are found in deeper waters on sandy substrates. We also identified seasonal reproductive aggregation patterns, always in relation to substrate types. Reproductive aggregation during the winter and early spring in the north-eastern continental shelf and the almost permanent (exception in autumn) concentration of juveniles in coastal waters around the central and eastern coast of Yucatan are of particular importance for management. These patterns represent seasons and areas of high fish vulnerability, which is the basic criterion for further analysis of protected areas.     

2010 World Expo and Urban Life Quality in Shanghai in Terms of Sustainable Development

Based on sustainable development theory and the UN＇s Human Development Index, this thesis puts forward what the quality of urban life implies, makes a study of the world Expo＇s potential influences on the urban life of Shanghai and advances the strategy and measures to strengthen the life-quality-facing urban management     

A critique of the official report on the evacuation of the World Trade Center: continued doubts

This paper criticises the conclusions and the unanswered questions in the National Institute of Standards and Technology (NIST)'s official report on the evacuation of the World Trade Center in New York City, United States, on 11 September 2001. It reviews the extent to which the report disregards several conventional statistical methods and comments on the NIST's refusal to share the machine‐readable data file with the scientific community for replication and further analysis. Problems lie in the sampling methods employed, the treatment of missing data, the use of ordinary least squares (OLS) with binary dependent variables, the failure to document the scalability of the scales used, the lack of tests to check for constant error variance, and the absence of overall fit tests of the model. There are also conceptual and theoretical issues, such as the absence in the report of considerations of the influence of group‐level processes and their impact on the collective behaviour of evacuating collectivities.     

POLLUTANT LOADING CAPACITY FOR THE BLACK RWER,CHEHALIS RWER SYSTEM,WASHINGTON1

ABSTRACT: The Black River, a tributary of the Chehalis River in western Washington State, has a history of widespread low dissolved oxygen (DO), anoxia in some locations, and fish kills. As part of a Total Maximum Daily Load (TMDL) study, environmental data were collected during two summer dry seasons and simulations were conducted with the WASP5 model to assess the effect of biochemical oxygen demand ( BOD ), ammonia, and nutrient loads on DO in the Black River. DO levels were below the State water quality regulatory criterion of 8.0 mg/L in almost all locations during the study. The slow middle reach of the river showed stratified conditions, with anoxia in some of the deepest pools. Based on model simulations, DO was found to still fall below the 8.0 mg/L criterion in the entire mainstem under “natural” conditions, and eutrophication was identified as a potential problem in the middle reach. A TMDL was proposed for BOD and ammonia that would prevent significant degradation of DO in the Black River. To prevent eutrophic conditions in the Black River, a TMDL for total phosphorus was proposed that establishes a protective criterion of 0.05 mg/L for the middle river during the dry low-flow season.     

岸坡侵蚀及其防治

岸坡侵蚀是土地侵蚀的一个类型．它进一步又可划分为岸坡崩塌、滑坡侵蚀，岸坡塌陷侵蚀，岸坡沟谷侵蚀和岸坡洪水侵蚀。本文在详细分析各类岸坡侵蚀的基础上，提出了岸坡侵蚀的特点和防治对策。     

Financing of wasteland afforestation in India

India has vast tracts of wastelands, which have been lying barren for ages. Most such lands are physically suitable for growing trees and thus could be put to socially productive uses. However, although usually economically viable, afforestation requires massive initial investment, generally beyond the means of the landowners. Also, government budgetary allocations do not cover current needs. In this situation, institutional credit is required. The National Bank for Agriculture and Rural Development (NABARD) of India has recognized this need and has devised a number of different schemes to provide refinance facilities to individuals and organisations. Although the number of forestry schemes refinanced by NABARD has increased rapidly in the past, they currently constitute only about 1% of the total number of loans sanctioned, and only about 2% of NABARD's cumulative loan disbursement to date. In fact, since 1992, the share of afforestation schemes has declined. A number of factors have been identified as major constraints, including time-consuming and complicated procedures for accessing land; restrictions on harvesting and selling trees; delays in sanctioning and disbursement of bank credit; non-remunerative prices for tree products; and flawed public policies and programmes. This article argues that unless these constraints are overcome, NABARD will not be able to play an effective role in speeding up development programmes in the forestry sector. It further argues that most of the current constraints on institutional credit for wasteland afforestation can be removed or relaxed. Practical strategies are suggested to mobilize more funds and channel more institutional credit for wasteland afforestation in India.     

世界与中国核电市场寿命周期探索

核电是高效、安全、清洁、经济的能源 ,但它和一切进入市场的产品一样 ,有其市场寿命周期。世界核电发展 5 0年 ,经历了市场寿命的投入期、成长期 ,现在处于成熟期 ;中国核电发展十多年 ,已进入成长期。笔者探索了世界与中国核电市场寿命分期 ,各期产生转换的动因 ,重点探讨了核电市场前景 ;同时认为 ,世界核电在未来的 2 0年左右 ,由于退役装机容量大于新增装机容量 ,可能出现阶段衰退 ,但会继续发展 ,进入新的寿命周期 ;而中国核电由于社会、经济快速发展 ,能源资源的不足 ,能源、电力结构调整与地区优化 ,环境与生态可持续发展等多方因素 ,仍需要不断发展 ,预测中国核电将有 6 0年以上的发展期。     

Ecosystem management: A comparison of greater yellowstone and georges bank

Ecosystem management links human activities with the functioning of natural environments over large spatial and temporal scales. Our examination of Greater Yellowstone and Georges Bank shows similarities exist between human uses, administrative characteristics, and some biophysical features. Each region faces growing pressures to replace traditional extractive uses with more sustainable extractive or noncommodity uses coupled with concern about endangered species. Ecosystem management as a set of practical guidelines for making decisions under evolving expectations is far from complete, and it embodies new demands on individuals and institutions. In each system these challenges are considered relative to: the public's symbolic understanding of the management challenge, ecosystem management ambiguities, information availability, information use, administrative setting, and learning capabilities of governance organizations Progress in making ecosystem management operational may occur as refinements in content and approach make it an increasingly attractive option for resource users, the public, and government officials.