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1.
Externalities are uncompensated influences that are not expressed in a market but that affect the production possibilities or the welfare level of third parties. An example is the noise pollution in airport areas. Although air transport is an important source of economic growth and employment in many countries, the social and environmental problems connected with this sector are rising rapidly. Consequently, airports are becoming a matter of concern to many politicians. On what kind of values should they base their decisions as to further growth or consolidation of the current situation? In this paper we discuss two approaches, one based on mainstream, neo-classical, economics, and one based on institutional approaches, more in particular new institutional economics, which can be seen as a development complementary to the mainstream.  相似文献   
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In the presence of biofilms, stainless steels (SS) exhibits an increase in corrosion potential, called ennoblement. In the present study, the corrosion potential (Eco,) behavior of the duplex SS UNS S32760 was recorded simultaneously with the in situ marine biofilm formation in two areas at Arraial do Cabo, Southeastern Brazil. The biofilm at Forno Harbor (an anthropogenically disturbed area) was characterized by higher relative abundances of Bacteria at day 2, followed by diatoms (especially Navicula sp.) on day 10 and dinoflagellates on day 18, whereas no clear trend was recorded at Cabo Frio Island (an undisturbed area). The ennoblement of Ecor values was site-dependent. In a complementary laboratory assay, biofilms were removed and the Eco values registered in sterile conditions for the subsequent 10 days and corroborated in situ results. Understanding biofilms and SS interactions has important implications for materials science and engineering decisions as well as helping to fill in imnortant gaps in this knowledge.  相似文献   
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This article examines fundamental questions concerning the origins and evolution of academic transport studies and the dynamics of its historical development. These fundamental questions are generally little discussed, yet are vital in gaining a better understanding of how the subject is driven forward. This article therefore attempts to answer these questions by taking the UK as a case study, with the principal method being evidence from semi-structured interviews with 20 senior figures integrally involved in the development of the subject. The characterization of transport studies provided by Allsop is employed as an analytical framework, enabling the construction of a historical narrative that can provide salient insights. Thus, it is argued that for academic transport studies the degree of early cross-fertilization with public arenas has meant that subsequent developments have been shaped by the subject's contextual environment. Most prominent among these developments has been the trend towards wider disciplinary breadth. This article examines the evolution of these processes, while the concluding section discusses their implications for consequent strengths and limitations of the subject.  相似文献   
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Time series measurements of flow and pigment concentrations (Chl) in the Menai Strait have revealed that the strong residual flow in a tidal channel ( 500 m3 s− 1) transports phytoplankton from the open sea into the channel where much of it is consumed by suspension feeders, mainly in commercial beds of Mytilus edulis. The progressive depletion of phytoplankton along the channel results in a strong horizontal gradient of plankton and hence Chl. Tidal displacement of this gradient causes large (± 50% of mean) oscillations of Chl in the vicinity of the mussel beds. Vertical mixing by the strong tidal flows is sufficiently vigorous for most of the tidal cycle to ensure that downward diffusion can resupply the near-bed layer although there are indications of some transient depletion around slack water.This paradigm of the interaction of advection, diffusion and filtration determining the distribution of plankton and its supply to mussels has been encapsulated in a series of simple models forced only by boundary values. In the first, a 1-D model of tidal flow in the channel reproduces the principal features of the observed currents including the unusually large spatial change in phase of the currents and the variation of the residual transport with tidal range. The flow field from this physical model is used to drive a second model based on the advection diffusion equation for Chl with a source at the Irish Sea boundary and a sink over the mussel bed. This model illustrates the formation of a strong Chl gradient along the channel and simulates the amplitude and phase of the M2 oscillations of Chl and the development of the M4 variation apparent in the observations. This second model has been extended to 2-D over the mussel beds to allow investigation of the effects of water column mixing. The model indicates that only for a short period ( 30 min), close to slack water, is mixing sufficiently reduced to permit the development of a depletion boundary layer and then only within  1 m from the bottom, a result which is consistent with the observations.  相似文献   
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Using photographs, this paper explores the gendered link between transport and the urban environment. It becomes apparent that moving around in urban spaces is an experience which is or can be fundamentally different for women and men. From pictures I conclude that a historical analysis of gender and urban transport ought to be a straightforward task to undertake: women are clearly visible in the visual record of the transport environment. However, a look at the historiography shows that research on gendering the city mostly deals with workplaces, women’s employment, class and race segregation in urban areas, welfare programmes specially designed to helped women, urban housing and marginalisation of women, housewives, healthcare, homeless women and politics. Gender and transport is hardly to be found: how women move and moved through urban space has not received sustained attention. Further, the main body of scholarly texts lacks in historical concern, stemming from such diverse disciplines as sociology, geography, economic and political sciences, women’s studies and planning.  相似文献   
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Intedis公司认为,汽车中每一个线束系统的成本结构都可以进行优化,我们的目标是实现每辆车的成本节省两位数欧元。本公司从电气电子产品之间的关联并以全方位的视角分析整个电子电气系统,以实现线束系统成本的最大优化。  相似文献   
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The past emphasis in this conference series has been on the best ways to deregulate regulated public transport markets. This workshop reverses this process by examining the best ways to regulate deregulated public transport markets. A hierarchy of regulatory needs is identified and three hybrid models examined, based loosely on experience from Great Britain, New Zealand and Sweden. It is argued that deregulated public transport markets are a global phenomenon but regulatory measures should reflect local requirements. The resultant process of glocalisation might result in regulatory measures that focus on the rules of law and their enforcement in emerging public transport markets (such as urban transport in Sub Saharan Africa and for the soon to be competitive inter urban market in Germany) but that focus on guidance for network integration and incentivisation for welfare maximisation in more mature public transport markets (as in Great Britain, New Zealand and Sweden).  相似文献   
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There has long been conflict over the degree to which railways should follow commercial or social investment criteria. This paper outlines the components of a comprehensive social cost‐benefit analysis of railway investment, and then describes the current approach in Britain. British Rail investment proposals are subject to a purely financial appraisal, although in the subsidized sectors of the railway this is subject to the proviso that a ‘broadly comparable’ level of service should be maintained. Local authorities and private operators are able to apply for a central government grant towards the cost of schemes they sponsor. But grant is only payable in respect of external benefits—that is, benefits other than to public transport users. Sponsors are also expected to seek contributions from private developers wherever possible. The difficulties to which this approach leads are discussed, and illustrated with two case studies of actual schemes. In one, it appears that failing to consider disbenefits to bus operators (and in turn to users of bus services) could lead to investments being undertaken which are not justified. In the other, a scheme which yields a high Net Present Value could not go ahead, in the form that we evaluated, because there is no way of recouping enough of the user benefits as revenue. Both are examples of the sort of distorting effect on decision‐making the current regime may have.  相似文献   
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