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981.
As the main organic pollutant in municipal living waste , kitchen waste causes secondary pollution in the course of its being gathered and transported to the landfill by mixing with other refuse and by decomposition. This makes pollution prevention more difficult and raises the cost of landfill engineering. However, the amount of solid waste to be treated can be decreased and such pollution burden lessened by disposing of the solid waste in local municipal areas. The program in Beijing also shows that this works well with our situation in China and can accelerate marketization and public participation.  相似文献   
982.
Arbitrary modeling choices are inevitable in scientific studies. Yet, few empirical studies in conservation science report the effects these arbitrary choices have on estimated results. I explored the effects of subjective modeling choices in the context of counterfactual impact evaluations. Over 5000 candidate models based on reasonable changes in the choice of statistical matching algorithms (e.g., genetic and nearest distance mahalanobis matching), the parametrization of these algorithms (e.g., number of matches), and the inclusion of specific covariates (e.g., distance to nearest city, slope, or rainfall) were valid for studying the effect of Virunga National Park in Democratic Republic of the Congo on changes in tree cover loss and carbon storage over time. I randomly picked 2000 of the 5000 candidate models to determine how much and which subjective modeling choices affected the results the most. All valid models indicated that tree cover loss decreased and carbon storage increased in Virunga National Park from 2000 to 2019. Nonetheless, the order of magnitude of the estimates varied by a factor of 3 (from −4.78 to −13.12 percentage points decrease in tree cover loss and from 20 to 46 t Ce/ha for carbon storage). My results highlight that modeling choices, notably the choice of the matching algorithm, can have significant effects on point estimates and suggest that more structured robustness checks are a key step toward more credible findings in conservation science.  相似文献   
983.
循环经济是以科学发展观为统领,以先进的科学技术为基础,以低消耗、低排放、高效率为特征的集约化、内涵式经济增长模式。为了促使我国走上循环经济发展之路,就必须建立循环经济科技支撑体系,即以政府为主导、企业为主体、社会化服务机构健全的循环经济科技创新体系和完善的循环经济科技政策体系、法律法规体系以及绿色文化与教育体系。  相似文献   
984.
Abstract: Water demand in a viable economy tends to be dynamic: it changes over time in response to growth, drought, and social policy. Institutional capacity to re‐allocate water between users and uses under stress from multiple sources is a key concern. Climate change threatens to add to those stresses in snowmelt systems by changing the timing of runoff and possibly increasing the severity and duration of drought. This article examines Snake and Klamath River institutions for their ability to resolve conflict induced by demand growth, drought, and environmental constraints on water use. The study finds that private ownership of water rights has been a major positive factor in successful adaptation, by providing the basis for water marketing and by promoting the use of negotiation and markets rather than politics to resolve water conflict.  相似文献   
985.
Abstract: The effects of streamflows on temporal variation in stream habitat were analyzed from the data collected 6‐11 years apart at 38 sites across the United States. Multiple linear regression was used to assess the variation in habitat caused by streamflow at the time of sampling and high flows between sampling. In addition to flow variables, the model also contained geomorphic and land use factors. The regression model was statistically significant (p < 0.05; R2 = 0.31‐0.46) for 5 of 14 habitat variables: mean wetted stream depth, mean bankfull depth, mean wetted stream width, coefficient of variation of wetted stream width, and the percent frequency of bank erosion. High flows between samples accounted for about 16% of the total variation in the frequency of bank erosion. Streamflow at the time of sampling was the main source of variation in mean stream depth and contributed to the variation in mean stream width and the frequency of bank erosion. Urban land use (population change) accounted for over 20% of the total variation in mean bankfull depth, 15% of the total variation in the coefficient of variation of stream width, and about 10% of the variation in mean stream width.  相似文献   
986.
Abstract: As nearly all of Texas’ rural lands are privately owned, landowner associations for the management of white‐tailed deer and ground‐water have become increasingly popular. Deer are a common‐pool resource with transboundary characteristics, requiring landowner cooperation for effective management. Ground‐water reserves are economically important to landowners, but are governed by the “rule of capture” whereby property rights are not defined. One ground‐water association and four wildlife management associations (WMAs) were surveyed to characterize their member demographics, land use priorities, attitudes, and social capital. Members of the ground‐water cooperative were part of a much larger, more heterogeneous, and more recently formed group than members of WMAs. They also placed greater importance on utilitarian aspects of their properties, as opposed to land stewardship for conservation as practiced by members of WMAs. If ground‐water association members could be more locally organized with more frequent meetings, social capital and information sharing may be enhanced and lead to land stewardship practices for improved hydrologic functions and sustained ground‐water supply. This, coupled with pumping rules assigned by the local ground‐water district, could yield an effective strategy that is ecologically and hydrologicaly sound, and that allows rural provision of water supply to urban consumers.  相似文献   
987.
The notion of creating marine protected areas (MPAs) in the high seas has been hailed as “an idea whose time has come”, and advocates are calling for them to be part of a global representative system to be established by 2012. It is argued in this paper that embedding the high seas MPA concept in the macro-goal of a global representative system subsumes more pragmatic and politically acceptable “micro-actions”. Development of politically contentious policy proposals such as high seas MPAs may have a better chance of success if they proceed by increments and are negotiated outside the limelight of a full scale, temporally defined global project. The following paper critically analyses the salience of international environmental agreements in the context of high seas MPAs and suggests a prototype MPA established by means of a negotiated agreement between a small number of countries which share political will and technological capacity to make a difference. Modelled on the recently implemented Titanic Accord, the prototypical high seas MPA would allow parties to develop a collaborative, rules-based regime which could be used to manage the actions of citizens involved in activities that may have a negative impact on the specified area.  相似文献   
988.
Abstract: Spatio‐temporal linkages between hydrologic and ecologic dimensions of watersheds play a critical role in conservation policies. Habitat potential is influenced by variation along longitudinal and lateral gradients and land use disturbance. An assessment of these influences provides critical information for protecting watershed ecosystems and in making spatially explicit, conservation decisions. We use an ecohydrologic approach that focuses on interface between hydrological and ecological processes. This study focuses on changes in watershed habitat potentials along lateral (riparian), and longitudinal (stream order) dimensions and disturbance (land use). The habitat potentials were evaluated for amphibians, reptiles, mammals, and birds in the Westfield River Watershed of Massachusetts using geographic information systems and multivariate analysis. We use a polynomial model to study nonlinear effects using robust regression. Various spatial policies were modeled and evaluated for influence on species diversity. All habitat potentials showed a strong influence along spatial dimensions and disturbance. The habitat potential for all vertebrate groups studied decreased as the distance from the riparian zone increased. Headwaters and lower order subwatersheds had higher levels of species diversity compared to higher order subwatersheds. It was observed that locations with the least disturbance also had higher habitat potential. The study identifies three policy criteria that could be used to identify critical areas within a watershed to conserve habitat suitable for various species through management and restoration activities. A spatially variable policy that is based on stream order, riparian distance, and land use can be used to maximize watershed ecological benefits. Wider riparian zones with variable widths, protection of headwaters and lower order subwatersheds, and minimizing disturbance in riparian and headwater areas can be used in watershed policy. These management objectives could be achieved using targeted economic incentives, best management practices, zoning laws, and educational programs using a watershed perspective.  相似文献   
989.
The regulatory structures underlying United States and European Union policies regarding genetically modified (GM) food and crops are fundamentally different. The US regulates GM foods and crops as end products, applying roughly the same regulatory framework that it does to non GM foods or crops. The EU, on the other hand, regulates products of agricultural biotechnology as the result of a specific production process. Accordingly, it has developed a network of rules that regulate GM foods and crops specifically. As a result, US regulation of GM foods and crops is relatively permissive, whereas EU regulation is relatively restrictive. Why are genetically modified food policies in the United States and the European Union so strikingly different? In the light of the recent World Trade Organization dispute on agricultural biotechnology, it may seem that economic interests are the driving force behind policies. While they are certainly part of the picture, the issue is far more complex. This paper argues that three different elements help explain differences between US and EU GM food policies. First, an investigation of US and European policies of the 1970s and 1980s on recombinant DNA research and of events leading up to early GM food and crop regulation allows a deeper understanding of current policy. Second, scrutinizing underlying values and norms can uncover the beliefs that condition current GM food and crop policy. Third, an analysis of involved actors’ views and levels of success in influencing policy is essential to understanding US and EU policies.  相似文献   
990.
The traditional vision of the role science should play in policy making is of a two stage process of scientists first finding out the facts, and then policy makers making a decision about what to do about them. We argue that this two stage process is a fiction and that a distinction must be drawn between pure science and science in the service of public policy. When science is transferred into the policy realm, its claims to truth get undermined because we must abandon the open-ended nature of scientific inquiry. When we move from the sphere of science to the sphere of policy, we pick an arbitrary point in the open-ended scientific process, and ask our experts to give us the answer. The choice of the endpoint, however, must always be arbitrary and determined by non-scientific factors. Thus, the two stages in the model of first finding the facts, and then making a decision about what to do, cannot be clearly separated. The second stage clearly affects the first. This conclusion will have implications about existing scientific policy institutions. For example, we advocate that the environmental assessment process be radically overhauled, or perhaps even let go. It will be our position that ultimately a better model for the involvement of scientists in public policy debates is that of being participants in particular interest groups (“hired guns”), rather than as supposedly unbiased consultants to decision-makers.  相似文献   
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