猴细小病毒Vp2的克隆、表达和鉴定

目的　克隆、表达和鉴定猴细小病毒 (simianparvovirus,SPV)Vp2蛋白。方法　用设计的SPVVp2区的特异性引物 ,PCR法扩增SPVVp2基因DNA片断 ;将获得的基因片断插入 pThioHisA载体中 ,转化大肠杆菌DH5α后挑选阳性克隆 ,利用限制性内切酶酶切和核酸序列分析技术鉴定重组质粒 ;以LB培养液培养转化有插入SPVVp2基因的pThioHisA载体的大肠杆菌 ,以终浓度 1mmol·L -1的IPTG诱导蛋白的表达 ;用SDA PAGE和Westernblot分析和鉴定表达的蛋白。结果　经限制性内切酶酶切和核酸序列分析 ,获得了插入pThioHisA载体框架的SPVVp2基因的表达质粒 ;阳性转化大肠杆菌在IPTG诱导下获得了SPVVp2蛋白的表达 ;SDA PAGE和用抗 Thio及抗 SPVVp2的特异性抗体的Westernblot分析证实了表达蛋白的特异性。结论　获得了SPVVp2基因的表达质粒并在大肠杆菌中得了高效表达 ,为进一步建立SPV感染的检测方法和研究SPV的血清流行病学等奠定了基础。     

Port competition with accessibility and congestion: a theoretical framework and literature review on empirical studies

This review interprets recent studies of the interactions between the competition of gateway seaports and the accessibility of landside transportation links to inland regions. Port competition is treated as part of a rivalry between two transportation chains. This article identifies the main modeling approaches and defines the different types of hinterland access systems described in the literature. A general theoretical framework is then proposed to incorporate those key components. The importance of the proposed framework is revealed by comparing and extending results from the literature. Major assumptions that need further empirical verification are identified and discussed, and related empirical studies are reviewed. Finally, avenues for further research are discussed.     

Impacts of trade liberalization on Chinese economy with Belt and Road initiative

China has been continuously implementing the open-door policy for past 15 years ever since it joined the World Trade Organization, which escalated international trade and demand for shipping. Compared with the other major importing countries in the world, China’s importing tariff is relatively low. Under the Belt and Road initiatives, more Free Trade Agreements to be concluded and more Free Trade Zones to be established, it is expected that the effective import tariff rate may continue to decrease in the future. This study analyses the impact of further reduction in Chinese import tariff rate on major economic indicators using a computable general equilibrium (CGE) model and based on the Chinese macro-economic data of 2012. The model results show that, with a balanced international payment, such a reduction can increase GDP, resident consumption, both imports and exports, and reduce GDP price, trade surplus, and government revenue. The results ease the concern that further import tariff reduction may harm the domestic production. Rather, it points out that there are still rooms to improve national economy and increase the consumer utility by trade liberation.     

Bicycle commuting in an automobile-dominated city: how individuals become and remain bike commuters in Charlotte,North Carolina

Transportation - In Charlotte, North Carolina less than one half of 1% of commuters ride a bicycle to work despite several decades of public investment in bicycle infrastructure and planning. Like...     

Port competition between Shanghai and Ningbo

The objective of this paper is to analyse the relative competitiveness of the neighbouring container ports of Shanghai and Ningbo in China and to develop a view of the likely future outcome of the competition between them. After assessing the demand for their services within what is hypothesized as a shared hinterland, current supply and future expansion plans are detailed and considered within the two ports' wider development strategies. The relative competitiveness of the two ports is then evaluated on the basis of price and quality of service, as embodied within the concept of generalized cost as incurred by customers. A critical political dimension is a necessary element of this analysis. It is concluded that continued economic development in the hinterland, central government policies on regional development and China's accession to the World Trade Organization (WTO) will all contribute to growing demand for port services. However, Ningbo will continue to gain greater market share as the result of advantages in its natural endowments (particularly depth of water), price (especially in terms of recovering the cost of capacity expansions) and quality of service improvements that are predicted to emerge as the result of currently planned enhancements to inland transport infrastructure and logistical systems.     

火与气的探查测绘

火与气的探测系统在许多现场扮演着安全方面极重要的角色。正规的安全评估常常假设火与气的探测系统可以减轻危险，然而在这方面却几乎没有标准的指导原则。要想对有关参数定量往往是很困难的，而想要确定在安全要求方面的预期性状或表述已达到的实际性状也往往无章可循。[第一段]     

Evaluating commuter opinion of congestion pricing in metropolitan Seattle

Continued growth and development in the Puget Sound region combined with existing geographic limitations have resulted in a transportation network that is at or near capacity for many hours during every weekday. Single‐occupancy vehicles (SOVs) remain the predominant mode of travel, despite a network of high‐occupancy vehicle lanes and regional transit. Given this situation, considering alternative methods to regulate traffic flow is necessary, and the implementation of a regional congestion pricing system is one such option. Although widespread throughout the world, congestion pricing has only recently been implemented in the United States.     

Container port systems in China and the USA: a comparative study

This study compares the evolution of container port systems in China and the USA in terms of port throughput, number of container ports and the concentration level in the container port system, based on the time-series data on these three features over the period 1979–2009 for China and 1970–2009 for the USA. The results show that the densities of container ports in the two countries are similar, and their evolutionary processes are alike, which has led to a comparable market structure in the port industries of the two countries. In addition, the disparities between container ports closely represent the unevenness in the regional economic development. We further compare the port management regimes of the two countries in terms of the administrative processes for port development and expansion, the ownership structure and the providers of port functions, which offer some explanation on the dynamics of port evolution in the two countries. In conclusion, it can be seen that the evolution of the container port system and the management regime in the USA can be a de facto reference for the future development of the Chinese container port system.     

Evolution and research trends of container shipping

The shipping industry was transformed by the expansion of international trade and technological innovation, notably containerization, since the 1960s. Accordingly, this was followed by a significant increase in research addressing different aspects of container shipping. Despite such availability, important questions have remained unanswered: what are the major contributions that the research community has made to the container shipping industry, global and regional economies? Have their contributions been skewed towards particular themes, directions, and geographical areas? What can the shipping research community learn from the evolution and trends of container shipping research so that they can continue to contribute to the well-being of the global and regional economies? To address these questions, the paper undertakes a critical review and analysis on the evolution and trends of research in container shipping in the past four decades, based on a collection of 282 papers investigating different topics in container shipping featuring in major scholarly journals between 1967 and 2012. The study enables the shipping research community to enhance self-understandings and identifies major gaps for further research.     

The utility analysis of risk attitudes in shipping

Many methodologies have been developed in order to optimize business decision making. By definition, optimization is only possible when an objective, or set of objectives, has been specified. However, the presence of risk obscures the potential payoffs of a particular decision. How different decision makers react to this phenomenon is reflected in the different objectives which they adopt. One corollary of this diversity of objectives is that any generally applicable optimization method must explicitly take into account the influence of risk attitude on decision choice. Because of the magnitude of the risks involved, virtually nowhere is this requirement more relevant than in relation to shipping decisions. This paper presents and justifies a method for assessing and measuring attitudes towards market risk. The method is applied to a sample of shipowners in Britain, Norway, Hong Kong and Greece and the risk profiles that are developed have some surprising, and important, implications for decision making in shipping.