中国、印度和世界的新秩序

中国和印度几乎同时出现在世界舞台表明国际事务的架构发生了史无前例的变化.这两个占世界人口40%的巨人,其人口相当于位居其后的20个人口最多国家的人口总和.在十九和二十世纪,这两个巨人长期在主宰国际事务的欧洲、日本和美国的阴影之下沉睡.     

非洲中部生态系统的碳排放及碳截留潜力

<京都议定书>中的<气候变化框架公约共同行动计划>和<清洁开发机制>要求对目前生态系统的碳蓄积、碳通量及碳截留潜力进行科学的理解,特别是对于碳贮库大但碳排放显著的、存在大面积和可重新造林土地的热带生态系统的了解.非洲中部拥有世界上10%的现有热带湿润森林,但有关该地区的碳研究甚少.1980年,非洲中部生态系统地上部分的碳蓄积为28.92Pg,到1990年则减少到24.79Pg.以增加生物量碳密度为目标而改善的森林管理能够截留18.32Pg的碳,到2050年还有超过50万km2原为森林的土地可以重新造林,从而增加截留10Pg的碳.了解生物量碳蓄积及其潜在截留量的空间分布对于通过<共同行动计划>和<清洁开发机制>所启动的碳贸易行动具有重大的意义.     

Book reviews

Rebuilding the City: Property‐led Urban Regeneration

P. Healey, S. Davoudi, M. O'Toole, S. Tavsanoglu & D. Usher (Eds)

London, E. & F. N. Spon, 1992, 312 pp., £30

Der Wert stadtnaher Wälder als Erholungsraum: Eine ökonomishce Analyse am Beispiel von Lugano (Value of Urban Forests as Recreational Areas: An Economic Analysis on the Case of Lugano)

Claudia Nielsen

Chur (Switzerland), Verlag Rüegger, 1992, 261 pp., SFr 48

Urban Planning under Thatcherism: The Challenge of the Market

A. Thornley

London, Routledge, 1991, 253 pp., £14.99

Sustainable Development and Urban Form, European Research in Regional Science 2

M. J. Breheny (Ed)

London, Pion, Limited, 1992, 292 pp., £28.00.

Tourism, Museums and the Local Economy: The Economic Impact of the North of England Open Air Musuem at Beamish

Peter Johnson & Barry Thomas

Cheltenham, Edward Elgar, 1992, 160 pp., £29.50     

Who cleans up the oil? A microeconomic study

Although oil spill cleanup requirements have existed in the United States for years, recent increases in oil imports and marine transportation of petroleum products as well as growing environmental concern have exposed a new industry, the Oil Spill Cleanup Industry. This paper explores some of the microeconomic aspects of this industry which has come under increased scrutiny by the general public, big business, and the federal government.In addition to a brief history and definition, several basic questions about the economic viability of the oil spill cleanup industry are raised and explored, and the impact on the industry of cleanup from government sources is examined, both from the perspective of present operations and from apparent future increases in federal participation. The primary dilemma facing the industry, that of providing continued and immediate supply while confronted with stochastic demand, is discussed. The effects of the large spill on the industry both in terms of revenue and ability to meet cleanup requirements is also considered.Information for the paper is drawn from past and continuing involvement in the U.S. Coast Guard's Marine Environmental Protection Program by both authors. The statistical evidence presented here was compiled through personal interviews and from two computerized Coast Guard information systems; PIRS (the Pollution Incident Reporting System), and SKIM (the Spill Cleanup Equipment Inventory System).     

An Application of a Modified Ecological Footprint Method and Structural Path Analysis in a Comparative Institutional Study

This paper presents an application of a modified ecological footprint method, using a regional, disturbance-based approach. In contrast to conventional institutional ecological footprint calculations, energy and land use resulting from all upstream production processes are explored by employing an input-output framework. Ecological footprints are calculated for two research institutions: the School of Physics (SoP) at the University of Sydney, and the Sustainable Ecosystems (CSE) Department of the Commonwealth Scientific and Industrial Research Organisation. These are broken down further in terms of land disturbance and greenhouse gas emissions, and as a function of production layer. To enable the use of the results in policy formulation, the ecological footprints are decomposed into detailed contributing paths, which are ranked according to their importance, using structural path analysis. The paper demonstrates that a considerable proportion of impacts occur upstream in industrial production. Thus a significant result of the study is the weight of obscure paths in the total footprints and, therefore, the importance of conducting an holistic assessment in order to ensure all upstream contributions are captured in the final impact of the institution.     

COLD WATER PATCHES IN WARM STREAMS: PHYSICOCHEMICAL CHARACTERISTICS AND THE INFLUENCE OF SHADING1

ABSTRACT: Discrete cold water patches within the surface waters of summer warm streams afford potential thermal refuge for cold water fishes during periods of heat stress. This analysis focused on reach scale heterogeneity in water temperatures as influenced by local influx of cooler subsurface waters. Using field thermal probes and recording thermistors, we identified and characterized cold water patches (at least 3°C colder than ambient streamflow temperatures) potentially serving as thermal refugia for cold water fishes. Among 37 study sites within alluvial valleys of the Grande Ronde basin in northeastern Oregon, we identified cold water patches associated with side channels, alcoves, lateral seeps, and floodplain spring brooks. These types differed with regard to within floodplain position, area, spatial thermal range, substrate, and availability of cover for fish. Experimental shading cooled daily maximum temperatures of surface waters within cold water patches 2 to 4°C, indicating a strong influence of riparian vegetation on the expression of cold water patch thermal characteristics. Strong vertical temperature gradients associated with heating of surface layers of cold water patches exposed to solar radiation, superimposed upon vertical gradients in dissolved oxygen, can partially restrict suitable refuge volumes for stream salmonids within cold water patches.     

VEGETATION INFLUENCE ON SMALL STREAM SILTATION1

ABSTRACT: A meandering stream channel was simulated in the Hydraulics Laboratory at Colorado State University and a series of tests was conducted using four types of vegetation to evaluate the potential effects of vegetation on sediment deposition and retention in a stream channel. The data collected included average flow velocity, flow depth, length of vegetation, density of vegetation, cross-sectional area of the vegetative stem, wetted perimeter of the vegetative stem, and injection and flushing time. The findings indicated that the vegetation could retain from 30 to 70 percent of the deposited sediments. The ability of vegetation to entrap and retain sediment is related to the length and cross-sectional area of the vegetation. The variables describing the flow and the vegetative properties were combined to form a predictive parameter, the sedimentation factor (S_d) that can be compared with the amount of sediment entrapped by vegetation in a stream system. A relation was developed correlating vegetation length to sediment retention after flushing for flexibility and rigid vegetation.     

DENSITY CURRENT INTRUSIONS IN AN ICE-COVERED URBAN LAKE1

ABSTRACT: Evidence is presented that snowmelt runoff from an urban watershed can produce density current intrusions (underflows) in a lake. Several episodes of density current intrusions are documented. Water temperatures and salinities measured near the bottom of a 10 m deep Minneapolis lake during the late winter warming periods in 1989, 1990, 1991, and 1995 show significant rapid changes which are correlated with observed higher air temperatures and snowmelt runoff. The snowmelt runoff entering this particular lake (Ryan Lake) has increased electrical conductivity, salinity, and density. The source of the salinity is the salt spread on urban streets in the winter. Heating of littoral waters in spring may also contribute to the occurrence of the sinking flows, but is clearly not the only cause.     

Employers′ knowledge of the hazard communication standard requirements and the perceived barriers to compliance

This study examined employers′ perceived knowledge of the Hazard Communication Standard (HCS) requirements prior to the inspection in which they were cited for an HCS violation. A lack of staff available to implement the HCS program was identified as having a significant impact upon compliance (p < 01). The perceived difficulty with compliance was also examined by the violations received by the organization. Those organizations cited for failing to have a written program identified a lack of staff available to implement the HCS requirements as having a greater impact upon compliance than those not cited for written program violations (p < 05). Suggested methods for improving the overall compliance with the HCS may include using the many compliance resources available through insurance companies, safety organizations, and state programs. Areas for further research include identifying the availability, use, and effectiveness of the outside safety and health compliance resources.