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141.
Resource estimates alone will not give advance warning of encroaching production difficulties. An analysis of the general stages in the evolution of petroleum production and discovery and of industry statistics provides an estimate of when the stage characterised by increasing production in the market economy countries outside the United States and Canada will end. The analysis indicates that the year of maximum production will be in the 1990s. Economic growth aggravates the difficulties accompanying the production decline by advancing the date of peak production and by increasing the adjustments that must be made as oil production declines. Des prévisions de ressources à elles seules ne constituent pas des signes précurseurs de difficultés croissantes de production. Une analyse des étapes générales marquant l'evolution de la découverte et de la production du pétrole ainsi que des statistiques industrielles nous permet de prévoir l'époque à laquelle prendra fin la phase de production accrue dans les pays à économie de marché en dehors des Etats-Unis et du Canada. Cette analyse révèle que l'année de production maximale se situera dans les années 90. La croissance économique accentue les difficultés qui accompagnent le déclin de la production de pétrole en avancant la date à laquelle cell-ci atteindra son plafond et en augmentant le nombre d'ajustements qui s'avèrent nécessaires au fur et à mesure qu'elle baisse. Las evaluaciones de recursos no dan por si solas un aviso anticipado de las dificultades de producción. Un análisis de las etapas principales en la evolución del descubrimiento y producción de petróleo y de las estadísticas industriales provee un estimado de cuando va a terminar la etapa caracterizada por un crecimiento de producción en los paises de economias de mercado otros que Estados Unidos y Canada. El análisis indica que el año de producción máxima se hallará en la década del 90. El crecimiento económico agrava las dificultades debidas a la declinación de la producción al adelantar la fecha de máxima producción (pico) y al aumentar los ajustes que deven hacerse cuando la producción de petróleos disminuye. 相似文献
142.
143.
This paper describes the help given by the social services department of a shipping company to bereaved families following a shipping disaster. In the absence of clear, factual and prompt information from an authoritative source, there is a tendency for bereaved individuals to deny their loss and thereby delay the process of mourning and eventual recovery. Appropriate intervention and support can help to overcome this tendency as was seen in the Madasa case. 相似文献
144.
Results of a recent intercomparison on the determination of trace elements in simulated air filter samples are reported. A large scatter of results is obtained for some elements and systematic differences between laboratories are observed. The performance of different methods, in particular neutron activation analysis and atomic absorption spectrophotometry, used by the various laboratories is discussed (air filter analysis; intercomparison; trace elements; control charts). 相似文献
145.
J A Heidman 《Journal - Water Pollution Control Federation》1975,47(6):1493-1498
146.
There is a growing recognition that knowledge of indigenous communities, based on accumulated observations and experience over time, is significant for sustainable environmental management in collaboration with modern scientific knowledge. A number of innovative policy initiatives are currently being implemented in New Zealand to enable indigenous Maori tribes and sub-tribes to rehabilitate and manage their local fisheries in accordance with customary values and practices. These policies are an important milestone from an historical perspective as they are meant to recognise and empower the role of Maori as Treaty partners. The fisheries management regime in New Zealand now provides for Maori representation at the local level within a co-management framework that enables local Maori communities to exercise their customary rights. These institutional arrangements have been crafted to facilitate Maori input, based on customary values and practices, to complement modern Western management practices for sustainable harvesting of marine resources. Nevertheless, the degree to which these initiatives constitute an adequate response to Maori Treaty aspirations is debatable. A major constraint in this respect is that the government is compelled to recognise the needs of other, economically and politically more dominant, non-Maori user-groups in allocating and managing access to fishery resources and the marine environment. 相似文献
147.
Laboratory column experiments run for up to 13 days compared air sparging of groundwater contaminated by dissolved petroleum hydrocarbons in sterile and non-sterile aquifer sediments as well as uncontaminated sediments and groundwater. Loss of dissolved BTEX compounds in the contaminated columns was very rapid, occurring through volatilisation. The majority of the dissolved total organic carbon (TOC) persisted for much longer periods however. A direct comparison between losses from sterile and non-sterile columns suggested a negligible contribution of biodegradation to the removal of TOC. This was difficult to confirm through examination of O2 utilisation because oxidation of a small amount of reduced sulphur in the aquifer materials was the dominant sink for O2. Despite this, it was possible to conclude that less than 22% of the removal of TOC was through biodegradation during the first three days of air sparging. 相似文献
148.
MICHAEL A. SCHUETT 《Environmental management》1997,21(2):239-246
/ This study intended to explore the perceptions of mountain bikingmanagement through a mail survey of state park directors in all 50 states.With a 100% response rate, it was found that 47 states permit mountainbiking in their state parks, however, few state parks have formalized plansto manage this outdoor activity. The management policies that do exist arenot followed on a statewide basis but vary within each state and at eachstate park. Many states have worked cooperatively with local mountain bikingclubs to develop and maintain mountain bike trails, promote rider education,and provide volunteer patrols on trails. The issue of user conflict surfacedwith almost three-fourths of the managers responding that conflict existedbetween mountain bikers and other trail users. This preliminary study shouldprompt further research with on-site managers focusing on the use ofmanagement plans for mountain biking, cooperation between managers and usergroups, and user conflict. It is recommended that an Internet-basedinformation clearinghouse or discussion group be made available to landmanagers by a national bicycling organization.KEY WORDS: Mountain biking; State parks; State park directors;Recreation resource management 相似文献
149.
Agricultural economics has, until the 1990s, enjoyeda reputation for relevance and usefulness to theagri-food industry and policy-makers. Thatreputation has been jeopardized by a growinginfatuation with models and quantification, and aconcomitant underemphasis placed on many complexproblems and issues of society. An illustrativeexample is explored, using agriculturalactivity-related damage to the natural resourcebase, environment and ecology. Agriculturaleconomists are urged to respond by broadening theirterms of reference and joining forces with otherdisciplines. 相似文献
150.
WILLIAM E. HOGSETT JAMES E. WEBER DAVID TINGEY ANDREW HERSTROM E. HENRY LEE JOHN A. LAURENCE 《Environmental management》1997,21(1):105-120
/ The risk tropospheric ozone poses to forests in the United States is dependent on the variation in ozone exposure across the distribution of the forests in question and the various environmental and climate factors predominant in the region. All these factors have a spatial nature, and consequently an approach to characterization of ozone risk is presented that places ozone exposure-response functions for species as seedlings and model-simulated tree and stand responses in a spatial context using a geographical information systems (GIS). The GIS is used to aggregate factors considered important in a risk characterization, including: (1) estimated ozone exposures over forested regions, (2) measures of ozone effects on species' and stand growth, and (3) spatially distributed environmental, genetic, and exposure influences on species' response to ozone. The GIS-based risk characterization provides an estimation of the extent and magnitude of the potential ozone impact on forests. A preliminary risk characterization demonstrating this approach considered only the eastern United States and only the limited empirical data quantifying the effect of ozone exposures on forest tree species as seedlings. The area-weighted response of the annual seedling biomass loss formed the basis for a sensitivity ranking: sensitive-aspen and black cherry (14%-33% biomass loss over 50% of their distribution); moderately sensitive-tulip popular, loblolly pine, eastern white pine, and sugar maple (5%-13% biomass loss); insensitive-Virginia pine and red maple (0%-1% loss). In the future, the GIS-based risk characterization will include process-based model simulations of the three- to 5-year growth response of individual species as large trees with relevant environmental interactions and model simulated response of mixed stands. The interactive nature of GIS provides a tool to explore consequences of the range of climate conditions across a species' distribution, forest management practices, changing ozone precursors, regulatory control strategies, and other factors influencing the spatial distribution of ozone over time as more information becomes available.KEY WORDS: Ecological risk assessment; GIS; Ozone; Risk characterization; Forests; Trees 相似文献