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31.
R/V POLARSTERN expedition ARK XVIII/1 in summer 2002 provided the opportunity to carry out a sampling programme to assess the activity, biomass and composition of the small-sized benthic biota (size range: bacteria to meiofauna) around the active mud-oozing and methane-seeping Håkon Mosby Mud Volcano (HMMV) on the SW Barents Sea slope, Northern North-Atlantic. A total of 11 stations, covering different areas (e.g., bacterial mat sites, and pogonophoran fields) within the crater, and sites outside the caldera were sampled using a multiple corer. Subsamples were analyzed for various biogenic compounds to estimate the flux of organic matter to the seafloor (sediment-bound chloroplastic pigments indicating phytodetritus), activities (bacterial exo-enzymatic turnover rates) and the total biomass [from bulk parameters, like phospholipid (PL) concentrations in the sediments] of the smallest sediment-inhabiting organisms (range: bacteria to meiofauna). Direct investigations of bacterial numbers and biomasses as well as on meiofauna densities and composition completed our investigations at HMMV. As expected for a comparable small deep-sea area with only minor disparity in water depth between sampling sites, our investigations revealed generally no significant differences in organic matter input from phytodetritus sedimentation between sampling sites inside and outside HMMV. Bacterial exo-enzymatic activities as well as total microbial biomass (TMB) and meiofauna densities, however, exhibited generally higher values at HMMV, compared to sites outside the mud volcano. Enhanced benthic life at HMMV is based on chemosynthetic processes, making the mud volcano a “chemosynthetic oasis” in an otherwise oligotrophic deep-sea environment. As we did not find any indication for bacterial symbioses in the meiofauna, comparably rich meiofaunal assemblages at HMMV are presumably indirectly related to a general enhanced biological production.  相似文献   
32.
A model of traveler behavior is proposed which is consistent with the possibility that travelers expend average daily amounts of time and money on travel with stable regularities both among urban areas and over time in the same area. The model is founded on economic utility theory. It is designed to forecast: (1) the amount of total travel generated by types of households, (2) the division of travel among available modes, and (3) the relationship between the amounts of time and money allocated to travel expenditures. The qualitative properties of the model are shown to be consistent with economic principles. Specific theoretical results reveal that, in the simultaneous presence of constraints on both time and money, travel budgets are not strictly constant proportions of income and time available as they are in the cases of single constraints relevant to classes of travelers to whom time is scarce compared to money, or conversely. Constant expenditure proportions are shown to be linear approximations which are subject to empirical validation. The relevant economic principle is that expenditures can be considered fixed in the short run but become flexible in the long run when utility maximization is applied to the expenditures themselves and not just to their allocation. Empirical tests of the model using data from three urban areas are positive, but additional tests are called for. The most important output of the research is deemed to be the establishment of theoretical hypotheses which can be used in continuing tests of travel budgets.  相似文献   
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34.
Trucking industry demand for urban shared use freight terminals   总被引:1,自引:0,他引:1  
The issue of shared use urban freight facilities first received attention during the 1970s when it was observed that, while inter-urban freight movements were becoming increasingly efficient, there were significant diseconomies in the movement of freight via truck within urban areas. Early research suggested that shared urban freight facilities should be constructed so that trucking companies could consolidate smaller shipments into larger ones. In the past few years, the concept of Urban Ports has gained increasing attention, not just for carriers who need to load and unload freight, but to provide a place near the urban center for truckers to wait out peak traffic periods. In this paper, using recently developed survey data, we examine trucking company interest in such facilities by examining the results of an ordered probit demand model.  相似文献   
35.
自从2005年初欧洲空气洁净法令颁布以来,微粒污染已经成为环境保护论者的主要议题.这一问题已经作为课题在罗马被激烈辩论过许多年.Trambus公交公司-城市公交的经营者,正在计划为其车队增加一种新车型,并已决定在正常工作条件下试用ZF Ecomat 6档全自动变速箱.结果表明,它能够降低6%的燃料消耗从而减少微粒污染,并且显著的降低了运营成本.  相似文献   
36.
公司是通勤交通的主要创造者,在与交通相关的讨论中,公司扮演着重要角色。近几年,公司提出了多种政策措施,以改善员工的出行条件,但其愿景与行动通常被研究文献所忽视。为了讨论比利时公司在交通政策方面的最佳实践,分析了现有研究成果和比利时的两次大规模通勤交通调查。首先,对公司进行分类,以便确定在推广替代交通方式方面受员工欢迎的公司。然后,通过量化分析确定交通政策的最佳实践。结果显示,最佳替代交通方式取决于公司特征;自行车交通最适合小型工作场所,大型工作场所和位于建筑密集区或市中心的公司则更适合推广公共交通;在公司交通管理中,财务激励、设施提供、信息传播和停车管理均起重要作用。  相似文献   
37.
The paper explores the role of stakeholder collaboration in the adoption of innovations as part of the environmental and sustainability agenda of port gateways. We do this through a comparative assessment of the port of Vancouver, British Columbia, and the twin ports of Los Angeles and Long Beach, California. An inductive research approach is used to identify and assess the initiation and implementation process behind exemplary innovations. Innovation includes new technologies and processes for handling and moving cargo, mechanisms for planning and policy making, as well as financing, implementing, upgrading, managing and operating infrastructure systems. A relatively new arena for competition on the basis of innovation concerns environmental performance. The conceptual framework and empirical evidence suggest that while there may be intense demand for and supply of innovation in port gateways, the complex dynamics of the logistics chain are such that successful innovation requires conscious involvement and collaboration of stakeholders.  相似文献   
38.
Employers are regularly involved in transport planning and characteristic workplace-oriented tools include: (1) travel plans for building projects, (2) mandatory travel plans, (3) subsidies to employers with an advanced travel plan and (4) best travel plan awards. In all cases, experts judge the level of car use. We argue that decision-makers might benefit from a multiple regression-based benchmark modelling tool that estimates the expected share of the car. In this paper, we estimate the share of car users in the commuting modal split at workplaces. However, since the amount of information available to experts differs, we gradually add information to the model to measure the impact of data availability. Without historic data on modal split, the current share can only be predicted moderately well, i.e. within a 20% range. Besides adding the past, results improve by using homogenous and regional subsamples. Nevertheless, quantitative analyses do not make expert knowledge obsolete.  相似文献   
39.
Allahviranloo  Mahdieh  Bonet  Thomas  Diez  Jérémy 《Transportation》2021,48(3):1125-1148
Transportation - Historically cities are formed to provide interaction and communication opportunities for communities. As cities become smarter, new forms of interactions are formed and the...  相似文献   
40.
This paper considers the issue of women's employment at sea in view of the current and predicted labour shortage in the industry. It reports on an International Labour Organization (ILO) commissioned study which aimed to explore employment policies and practices regarding women seafarers and the experiences of women seafarers themselves. The data suggested that those employers who had experience employing women seafarers were generally very positive about their skills and abilities. Women seafarers themselves were dedicated and committed to a sea-going career. The paper concludes that women seafarers are an under-recognized resource and, if utilized, could fill labour shortages in the industry, both in sea-going positions and in marine positions ashore that require sea-going experience. A series of recommendations are outlined in order to promote the recruitment and retention of women at sea.  相似文献   
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