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171.
Specialization in cargoes and forelands is defined for the ports of Montreal, Quebec, Saint John, and Halifax using a variation of the location quotient. Economic impact is also defined using the location quotient. All ports are shown to have some degree of specialization; whereas, Saint John and Halifax have relatively greater economic impact. It is suggested that the four ports should be encouraged to develop their specializations. However, are the benefits to the shipping industry in following such a policy outweighed by the losses to the local economies because investment in certain ports does not take place?  相似文献   
172.
My bowels boiled and rested not: the days of affliction prevented me. (Job 30: 27.)  相似文献   
173.
In recent years the measurement of productivity has increasingly focused on measuring total factor productivity or TFP. Additional research has investigated the reasons for differences in TFP between firms. The implicit assumption behind this work is that simpler measures of industry productivity (such as revenue ton-miles per employee) can seriously misstate both the level and growth rate of productivity. As a result, accurate analysis of productivity requires information on TFP. While this argument is not open to debate on a theoretical basis, the extent that simple measures of productivity inaccurately portray TFP has not been investigated in anything but a cursory manner. This paper investigates the relationship between typical industry measures of productivity and TFP using a data set of U.S. and non-U.S. airlines for the period 1970–1983. The paper examines both levels of productivity and growth rates. The results indicate the extent to which industry measures accurately or inaccurately reflect the more comprehensive measure of productivity (TFP). To the extent that industry measures are inaccurate, this paper investigates the possible sources of error in order to determine if slightly altered industry measures might more accurately reflect TFP.  相似文献   
174.
In contemporary times, Public–Private Partnership (PPP) in transport infrastructure has gained considerable attention in developing regions following its success in the developed countries. However, Sub-Saharan Africa (SSA) is among the developing regions with few transport PPP projects and among the regions with high number of failed projects. Meanwhile the region's transport infrastructure need far exceeds it current provision. This paper therefore aims to examine the project experiences (success and failure factors) of three highly profiled transport PPP projects, namely the Lekki toll road concession project (Nigeria), N4 toll road (South Africa/Mozambique) and Port of Maputo (Mozambique) in order to develop policy measures for effective future implementation. The experiences of the three projects show that transport PPP policy is indeed feasible in SSA. However, to realise its full applicability, proper policy actions and measures must be carefully observed and these include effective and efficient stakeholder management, transparent and competitive tendering process, high participation of local investors, stable macro-economic conditions and strong government commitment and regulatory framework. The projects experiences and policy actions developed are impactful in accelerating transport infrastructure development through PPP approach in SSA. Hence it is hoped that policy-makers and practitioners would be informed on the key strategies to employ in implementing future projects.  相似文献   
175.
就美国交通的基本情况、发展模式、交通工具的选择和新技术的应用、智能交通系统及私有化和外包等诸多方面进行了深入的探讨,对美国交通的发展趋势做出了详尽而有理有据的预测,这样的综合介绍无疑会使我国的交通规划与发展颇受裨益。  相似文献   
176.
    
The insufficiency of infrastructure capacity in an air transport system is usually blamed for poor punctuality performance when implementing flight schedules. However, investigations have revealed that ground operations of airlines have become the second major cause of flight delay at airports. A stochastic approach is used in this paper to model the operation of aircraft turnaround and the departure punctuality of a turnaround aircraft at an airport. The aircraft turnaround model is then used to investigate the punctuality problem of turnaround aircraft. Model results reveal that the departure punctuality of a turnaround aircraft is influenced by the length of scheduled turnaround time, the arrival punctuality of inbound aircraft as well as the operational efficiency of aircraft ground services. The aircraft turnaround model proposed is then employed to evaluate the endogenous schedule punctuality of two turnaround aircraft. Model results, when compared with observation data, show that the operational efficiency of aircraft ground services varies among turnarounds. Hence, it is recommended that the improvement of departure punctuality of turnaround aircraft may be achieved from two approaches: airline scheduling control and the management of operational efficiency of aircraft ground services.  相似文献   
177.
以台湾隧道为背景,搜集整理1990年代以来安全检测作业调查所得的异状,并纳入相关报导中早期隧道的破坏案例,继而区分不同的异状及其类别,并探讨采用砖(石)砌、混凝土与钢筋混凝土等不同的衬砌材料以及不同构筑方式之隧道所发生的异状形态.  相似文献   
178.
    
ABSTRACT

It is essential that the pedestrian environment accommodates all users so they can participate in everything the community has to offer. However, people with disabilities (PWDs) often find it difficult to navigate this environment because of physical and social accessibility factors. While we know a great deal about which factors act as barriers and facilitators to mobility, we do not know enough about how they influence navigation (i.e. planning a route, en route decisions, and route learning) or how they can be improved. A scoping review was conducted to identify these factors, assess their implications, and suggest future directions. In total, 3394 studies were found and screened, 163 full-text articles were reviewed, and 37 articles met the inclusion criteria for the final review. These studies focused on those with visual impairments, navigating crosswalks, and the cognitive elements of navigation. Future research is needed that includes more types of disabilities, considers the navigational process from planning to arrival, and evaluates interventions.  相似文献   
179.
Althoughadultmammalianhepato-cytesarehighlydiferentiatedandnonpro-liferatingcels,theprimaryculturesofadultrathepatocytescanbe...  相似文献   
180.

The use of third-party logistics services by large US manufacturers continues to grow. Increasingly, those services are used to support international sourcing and sales activities. Use of these services is often triggered by specific events such as a corporate restructuring, a top management change or a benchmarking effort. Nearly two-thirds of users report they experienced significant impediments in implementing third-party agreements. After starting conservatively, the typical user buys a wide variety of logistics services. Users generally report that buying logistics services has had a positive impact on their organizations, particularly with respect to logistics costs and customer service. However, many also report negative impact on employee morale linked to downsizing the logistics workforce. More than two-thirds of users report cancelling at least one-third-party logistics contract. Nevertheless, if given complete responsibility to make the decision, >70% of users would increase their companies' use of such services.  相似文献   
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