Decades of research has generated new scientific understanding and technologies aimed at better managing environmental change in estuarine and coastal regions. Yet many across the communities of coastal and estuarine research, management, and funding believe that progress has been too slow in applying this research in practice. This essay reviews how the National Estuarine Research Reserve System’s funding program evolved over the past two decades to improve how researchers and users of research work together to increase the uptake of science to achieve resource management and conservation goals. Incremental innovation in the design of the NERRS funding program enabled more intensive and multiway engagement between funders, researchers, and users, which created new pathways for applying science in practice. Furthermore, these interactions stimulate reflection and adaptation within each separate institutional setting, supporting changes that may science to better support environmental problem solving. 相似文献
The aim of the present study is twofold. First, to provide new information concerning the technical characteristics of urban bus companies on the basis of a sample of medium and large-size cities in Spain. Second, to analyze the degree of efficiency of those companies and to quantify the reasons for this efficiency. The results should be useful in evaluating possible changes in public policies relating to urban transport, specifically changes in the way the market is organized and in pricing.The analysis is carried out by estimating a cost function. The sample is made up of a panel data set consisting of observations of nine Spanish companies that operated during the period 1983–1995. The specified functional form is translogarithmic. The output unit of measure adopted is bus*kms run. The cost function includes the network length for each company, thus permitting evidence concerning economies of density and economies of scale.The use of panel data allows us to estimate the cost function, taking into account that each company is affected by the specific characteristics of each individual city, the different features of the network in question and by different levels of efficiency. The economies of scale have been calculated, taking into account that the features of the network and of the city – represented by their specific individual effect – will vary with the company's level of output.Finally, an analysis is made of the relative productive efficiency of the companies, as well as of the variables likely to influence that efficiency. 相似文献
This paper pursues three goals: (1) determining the relative importance of built environment barriers limiting walkability, (2) analyzing the existence of an asymmetry in the way people evaluate positive and negative built environment characteristics, and (3) identifying solutions to tackle the main barriers and quantify their impact in walkability. A best–worst scaling survey was developed to compare the importance of eight different attributes of the built environment regarding walkability. Model results show an asymmetry negative–positive in the judgment and choice of built environment characteristics that promote and impede walkability. The most important barriers, obtained from worst responses, are connectivity, topography, sidewalk surface and absence of policemen. Walkability scores were computed for different neighbourhoods and different policy scenarios were forecasted. Simulation results from the worst responses indicate that improvements in sidewalk quality, along with an increase in the number of police officers, lead to an 85% increase in the walkability score for the lower income neighbourhoods.
Traffic forecasts provide essential input for the appraisal of transport investment projects. However, according to recent
empirical evidence, long-term predictions are subject to high levels of uncertainty. This article quantifies uncertainty in
traffic forecasts for the tolled motorway network in Spain. Uncertainty is quantified in the form of a confidence interval
for the traffic forecast that includes both model uncertainty and input uncertainty. We apply a stochastic simulation process
based on bootstrapping techniques. Furthermore, the article proposes a new methodology to account for capacity constraints
in long-term traffic forecasts. Specifically, we suggest a dynamic model in which the speed of adjustment is related to the
ratio between the actual traffic flow and the maximum capacity of the motorway. As an illustrative example, this methodology
is applied to a specific public policy that consists of suppressing the toll on a certain motorway section before the concession
expires. 相似文献
Of the many public initiatives used to promote the use of bicycles in the urban environment, the one that has achieved the most spectacular results in a short period of time is the public bicycle hire system. The experience of Seville is one of the most successful internationally, where 6.6 % of mechanised trips were being made by bicycle within 30 months. This paper analyses this experience in the university community, which represents one-third of system users. We conclude that the people who are most satisfied with the system are those who use it for leisure and recreation activities, non-residents of the city, more environmentally aware people and those who have no alternative mode of transportation. Their satisfaction is also closely linked to their appreciation of the bicycles’ level of comfort, the ease with which users can hire bicycles and return them and the small amount of paperwork involved required to sign up for the system. However, user appreciation has fallen over time because the system’s rapid success has caused it to become overloaded. This experience therefore provides one main lesson: the system’s success can result in eventual difficulties. 相似文献
The objective of this paper is the comparison of the efficiency levels for a set of European rail companies in monopoly situations with respect to hypothetical duopoly situations. More specifically, the aim is to test whether the operating costs function of such companies is subadditive. A cost function is subadditive when a single firm can produce all relevant output vectors cheaper than two or more firms. In order to do so the test developed by Evans and Heckman (1984) will be used. It was applied for the American phone company Bell System to assess the convenience of separating the management of local and long-distance services. The results indicate that at least for the companies of a greater size, an efficiency increase (as measured by lower costs), would be obtained from the separation of the current companies in two different companies of a lower size. Besides, these efficiency gains are greater when the two new companies specialize their production, either on passenger or on freight traffic. 相似文献
It is a fact that coastal zones in the Mediterranean are becoming progressively more seriously degraded. Instrumental to the phenomenon in Spain is the evident failure of the coastal management that the institutions have pursued for over three decades, both under the old, state-centralized model, and the new organizational model with the political division of land into autonomous regions. This failure can in part be explained not only by the inadequate tools the administration possesses to address the dynamism and complexity of the new economic activities that have sprung up along the coast, but also by incoherent sectoral policies. Finally, there has been no all-encompassing political strategy capable of dealing with coastal communities' demands for development and the need for the protection of ecosystems and their natural resources. All this has resulted not only in a deterioration of the area, but also in the discrediting of actions implemented by the institutions, and their plans and programs being perceived as an obstacle to economic development. 相似文献