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291.
292.
浮置板轨道结构在城市轨道交通减振降噪上的应用 总被引:11,自引:0,他引:11
随着城市轨道交通的快速发展,其引起的振动和噪声问题得到国内外的重视,如何采用有效的减振降噪措施降低振动的环境影响成为热点问题之一。浮置板轨道隔振措施在国外有几十年的历史,得到广泛的应用,并在近几年成功应用于我国的城市轨道交通系统。在目前的减振措施中,浮置板轨道减振效果最好,可达20~40dB。根据不同的分类方法,评述了浮置板轨道的种类及应用情况,运用动力学原理分析了浮置板轨道的隔振原理。详细介绍了浮置板轨道在国内外应用的实例和减振降噪实测结果,认为浮置板轨道结构是一种高效的减振降噪措施,具有广阔的发展前景。 相似文献
293.
Dunes that are protected because of their very rich and diverse plant communities are often exposed to excessive visitor pressure.
The effects of trampling on the habitat must be known from a conservation viewpoint but also are important for management.
To determine the response of plant assemblages to trampling by people, an experimental study was conducted on the state-owned
dunes at Quiberon (Brittany, France). Indices of resistance and resilience were used to compare three typical plant communities
belonging to the various landscape units: mobile dune, semifixed dune, and fixed dune. The strong contrasts between communities
belonging to different successional stages reflect their ecological functioning. The mobile dune and semifixed dune with their
low resistance contrasted with the fixed dune. Only the vegetation cover of the semifixed dune benefited from long-term trampling
and had a very high resilience (134%). This response could be explained by a good balance of two opposite factors: soil compaction
increasing soil stability and moisture content, and vegetation destruction. Because of their low resilience, trampling seems
to be harmful for fixed dunes in the long term. The tourist pressure seems easier to integrate in to the mobile dunes and
the semifixed dunes if periods of recovery are included in the management. 相似文献
294.
Prospects for the co‐management of mangrove ecosystems on the North Brazilian coast: Whose rights,whose duties and whose priorities? 总被引:2,自引:0,他引:2
This article describes the co‐management approach in situations of open access to and of increasing pressure on resources, using a mangrove coastal zone in North Brazil as an example. Co‐management clearly has the potential to turn nonviable, de facto open access to mangroves into effective common property management. Alliances of different political and ideological groups have been formed under the RESEX (reservas extrativistas — natural resource user reserve) model of coastal co‐management. Local economic interests have been mobilized as client constituencies. The RESEX system of co‐management assigns additional duties to both co‐managing parties, i.e., the state administration and the local users, in exchange for new rights. The authors argue that local support for the RESEX model has been gained on partially distorted premises. As the public authority passes on responsibility for management to local users under the RESEX model, this entails a number of duties for the local users. Thus local users assume the duty to implement and monitor resource management; they also appear to gain the right to take local decisions, such as excluding outsiders from resource access, and designing local resource management rules. However, as this article shows with two examples, some important new rights for local users under the RESEX co‐management concept are contrary to environmental legislation in force. This conflict is at present unresolved. It is argued that increased transparency about their precise rights for local resource co‐managers will considerably improve the prospects of coastal co‐management in Brazil. 相似文献
295.
Sylvie Pouteau 《Journal of Agricultural and Environmental Ethics》2002,15(3):289-303
Substantial equivalence (SE) has beenintroduced to assess novel foods, includinggenetically modified (GM) food, by means ofcomparison with traditional food. Besides anumber of objections concerning its scientificvalidity for risk assessment, the maindifficulty with SE is that it implies that foodcan be qualified on a purely substantial basis.SE embodies the assumption that only reductivescientific arguments are legitimate fordecision-making in public policy due to theemphasis on legal issues. However, the surge ofthe food debate clearly shows that thistechnocratic model is not accepted anymore.Food is more than physico-chemical substanceand encompasses values such as quality andethics. These values are legitimate in theirown right and require that new democraticprocesses are set up for transverse,transdisciplinary assessment in partnershipwith society. The notion of equivalence canprovide a reference scale in which to examinethe various legitimate factors involved:substance (SE), quality (QualitativeEquivalence: QE), and ethics (EthicalEquivalence: EE). QE requires that newqualitative methods of evaluation that are notbased on reductive principles are developed. EEcan provide a basis for the development of anEthical Assurance as a counterpart of QualityAssurance in the food sector. In France, asecond circle of expertise is being set up toaddress the social issues in food public policybeside classical risk assessment by the firstcircle of expertise. Since ethics is likely tobecome an organizing principle of the secondcircle, the equivalence ethical framework canprove instrumental in this context. 相似文献
296.
Juha Peltomaa Mikael Hildén Suvi Huttunen 《Journal of Environmental Policy & Planning》2020,22(2):268-280
ABSTRACTDuring policy change, the role of the actors communicating the change to different audiences is accentuated. The media plays an increasing role, either as an actor or by providing a stage for other actors. In particular, specialised journals represent an influential, albeit understudied, sphere of policy studies. We use the narrative policy framework complemented with frame analysis to trace how specialised media can affect policy implementation through implicit suggestions for action. Using this combined approach, we analyse how specialised forest journals, which are the most important forest information source for Finnish forest owners, have conveyed the renewal of forest legislation in Finland. The core message of the journals is that forest owners should, despite their new freedom granted by the reform, rely on experts rather than experimenting when managing their forests. This suggests that the media contributes to a path-dependent continuation of a forest policy that is based on a rationalistic exploitation ethos. The innovative potential, which the policy change aimed at encouraging, is thereby partially undermined. However, the analysis of the narratives also reveals that forest expertise and professionalism are diversifying. This notion is important as diversity can eventually lead to narratives supporting more fundamental change in forests management. 相似文献
297.
Accountability has hardly been studied in the governance of climate change adaptation. This paper develops a framework for assessing the accountability of interactive governance arrangements for local adaptation. This framework is based on five important accountability mechanisms: Clear responsibilities and mandates, Transparency, Political oversight, Citizen control and Checks and sanctions. For illustration purposes, the proposed framework is applied to the case of a Dutch local adaptation governance arrangement. The application shows that the five proposed mechanisms and their operationalizations offer a valid assessment of the accountability of such arrangements. It also raises some challenges, such as the tensions between accountability and flexibility, legitimacy and effectiveness; the potentially important roles of trust and of the political skills of central actor(s) in the arrangement in raising accountability, and the potential need to distinguish between arrangements for policy planning and for service delivery. 相似文献
298.
The seal failure of tubing and casing connections compromises underground gas storage well safety. This work proposes a systematic uncertainty analysis framework for connection sealability assessment. The framework covers reliability analysis and reliability sensitivity analysis and attempts to provide more effective support for the reliability design of connection seals. The reliability analysis introduces an adaptive Kriging with stopping criterion P-Monte Carlo simulation (AKP-MCS) method, which can provide a satisfactory estimate of failure probability with a small number of performance function evaluations. This metamodeling technology can effectively reduce the numerical efforts required for the reliability assessment of connection sealability. In the reliability sensitivity analysis, the refined metamodel obtained from the reliability analysis is coupled into a single-loop Monte Carlo simulation (MCS) method. The classifier attribute of this metamodel can meet the requirement of the single-loop MCS method to classify the signs of sampling points. This attribute enables sample matrices to be evaluated on this metamodel instead of the performance function, making the reliability sensitivity assessment more feasible. The proposed method is first demonstrated with four academic examples with promising results. Next, an illustrative tubular connection case is provided. The proposed scheme gives estimates of the failure probability and reliability sensitivity close to the classical model but requires less computational cost. The results of the analysis can provide useful information for the scheme decision-making and reliability optimization of connection seal design. 相似文献
299.
Cornelia E. Nauen 《Environment, Development and Sustainability》2008,10(5):605-622
The paper examines preliminary experiences with international scientific cooperation in fisheries, aquaculture and coastal
zone issues through 90 projects in successive European Research Framework Programmes (FP4–FP6: 1994–2006). FPs had increasingly
ambitious objectives in response to international commitments, such as the Convention on Biological Diversity, the Millennium
Development Goals, the Johannesburg Plan of Implementation and dialogue with partner regions. Sustainable aquatic food production
in the context of respect for ecosystems was a central concern. Engagement with different social actors and attention to investment
in education, people and institutions enabled uptake of research results in education, innovation and some impact. The emphasis
in several recent projects on more integrated analyses and knowledge products in the public domain is an encouraging response
to the growing crisis of aquatic resource systems. It is suggested that significant up-scaling will be required. This might
be done through institutional internalisation and better translation of research results into policy developments supportive
of transitions towards sustainable production systems and ecosystem rehabilitation. Capacity building to use research in novel
ways and other enabling mechanisms need to be put in place to increase societal and environmental benefits of the research.
相似文献
Cornelia E. NauenEmail: |
300.
Policy concerns related to the environment have grown in the past decadesfrom relatively local and well-defined problems to increasingly complex andglobal issues. With this has grown the need to develop the capacity tointegrate, reconcile, organize, and communicate knowledge across scientificdisciplines, as well as to make this knowledge available and useful for policy-makers. One response to this has been the growing field ofIntegrated Assessment (IA). Our goal in this paper is to reflect on the purpose and valueof IA in principle. We propose a conceptual framework within whichindividual IA studies, and the practice of IA as a whole, can be placed andevaluated. The framework addresses both the integrative nature of IAs andtheir policy usefulness, including a self-awareness of their role and capabilities. We illustrate several stages in the evolution of integrated assessments: fromlinear to more complex chains of analysis, from non-adaptive to perfectly-adaptive to realistically-adaptive agents, from simplistic to sophisticated to pluralistic consideration of alternative underlying development paths, from strictly quantitative to quantitative and qualitative analyses, from science-driven to policy-driven, and from analyses that dictate to users to those that involvethose users in the actual assessment process. By so doing, we argue for botha richer form and process of IA. Ultimately, we feel that it may also benecessary to reconsider the framing of the questions that IAs have been askedto address, perhaps leading to the consideration of the use of other forms of mandated science. 相似文献