雌激素与盐敏感高血压的关系

目的　进一步探讨植物性雌激素和内源性雌激素对雌性自发性高血压鼠 (SHR)的盐敏感高血压反应的保护作用。方法　对三周龄雌性SHR行卵巢切除术 ,饲以 0 .1mol·L- 1 或 1 .4mol·L- 1 NaCl,含或不含植物性雌激素之食物。 1 0周龄时 ,腹主动脉内植入遥测传感器 ,用“计算机腹主动脉血压遥测系统”2 4h连续测量血压、心率及整体活动。静脉注射六甲双铵阻断交感神经系统活动后 ,记录动脉压和心率反应。结果　食用无论是否富含植物性雌激素的高盐食物 ,动脉血压都明显增高 ,不含植物性雌激素组更甚。交感神经系统活动阻断后 ,引起所有各组鼠夜间动脉压急剧降低。结论　食物中所含之植物性雌激素可降低雌性SHR的盐敏感高血压反应。交感神经系统兴奋性异常在高盐食物引起的血压增高中起重要作用     

Impact of pricing and transit disruptions on bikeshare ridership and revenue

Transportation - Bikeshare operators routinely explore options to improve ridership and revenue by studying interaction among pricing, service and operations. The objective of this research is to...     

The relationship between coastal-zone management and off-shore economic development

‘Coastal-zone management is ideally founded on a consideration of the full range of bio-physical and socio-economic elements integrated through problem perception, decision making and remedial strategy planning. Specification of the framework indicates a variety of potential links between the coastal zone and continental shelf development.’     

Ranking of factors contributing to higher performance in the ocean transportation industry: a multi-attribute utility theory approach

The North American Free Trade Agreement (NAFTA) signed by Canada, the U.S.A. and Mexico and which came into effect on 1 January 1994, is a significant move towards further integration of the North American economies. This paper examines the likely impact of NAFTA on Canadian ports. Three channels of impact are identified. First, there are direct impacts on trade flows between Canada and its North American trading partners. In this regard we find that ports do not typically handle the types of products that are likely to be affected by NAFTA, and so the direct impacts may be minimal. Second, and more significantly, port catchment areas are likely to undergo substantial changes as they respond to a more competitive environment within the free trade area. Third, the transportation sector has itself been included in NAFTA, and Canadian ports will face increased competition from land based transportation modes. We conclude that ports in Canada must learn to work more consciously as agents of regional economic development.     

Damage detection of offshore jacket structures using frequency domain selective measurements

The development of damage detection techniques for offshore jacket structures is vital to prevent catastrophic events. This paper applies a frequency response based method for the purpose of structural health monitoring. In efforts to fulfill this task, concept of the minimum rank perturbation theory has been utilized. The present article introduces a promising methodology to select frequency points effectively. To achieve this goal, modal strain energy ratio of each member was evaluated at different natural frequencies of structure in order to identify the sensitive frequency domain for damage detection. The proposed methodology opens up the possibility of much greater detection efficiency. In addition, the performance of the proposed method was evaluated in relation to multiple damages. The aforementioned points are illustrated using the numerical study of a two dimensional jacket platform, and the results proved to be satisfactory utilizing the proposed methodology.     

Low-aspect ratio appendages for wind-assisted ships

Journal of Marine Science and Technology - Wind propulsion for commercial ships has been identified as a key component in the energy transition for the maritime industry. The sailing hybrid ship...     

The development of road and rail transport safety valuation in the United Kingdom

An extensive body of theoretical and empirical work has been undertaken in the UK since the middle of the last century on the estimation of values of safety for use in the appraisal of proposed transport projects, particularly road and rail. This research has focused largely on ‘willingness-to-pay’ based values in order to measure the strength of the travelling public's preference for marginal improvements in transport safety, relative to consumption of other goods and services. In terms of practical policy making, the research has resulted in a set of values for the prevention of statistical fatalities and non-fatal injuries that are applied not only in transport safety decision making, but also in other public sector contexts. This paper summarises the main findings of this research.     

Ludwig?s Ratchet and the Collapse of New England Groundfish Stocks

The stocks of principal groundfish species off New England have collapsed, creating economic hardship and dislocation in fishing communities from Rhode Island to Maine. In this article we analyze the causes of this collapse using the ?ratchet effect? described by Ludwig, Hilborn, and Walters (1993) as a framework. According to Ludwig, Hilborn, and Walters, powerful economic and political interests drive fisheries to overcapitalize and overexploit despite scientific evidence that stocks are declining. When the fishery is no longer economically viable, governments provide financial assistance to minimize economic hardship. When stocks increase there is another rush to invest, and the cycle repeats itself. The history of groundfish management in New England conforms well to this model. Optimism among fishers and government over U.S. control of this fishery in 1977 stimulated successive rounds of investment that built up excessive fishing capacity despite warnings from scientists that stocks were becoming weaker. Management regimes designed by the New England Fishery Management Council were ineffective in constraining fishing effort. Collapse of the stocks has led to severe restrictions on fishing and to government assistance. We suggest that the integration of science, management, and harvesting sectors through ecosystem-based management offers the best means of avoiding similar situations in the future.     

Proximité aux infrastructures et croissance de l’emploi en ?le-de-France (1993–2008) : le r?le des transports à l’échelle intramétropolitaine

This article aims to analyze the role of proximity to transport infrastructures in employment growth within 291 municipalities located in the ?le-de-France region between 1993 and 2008. Based on the employment data from Unistatis, a multiple regression econometric model is estimated, first without variables describing proximity to infrastructure, and then integrating them in order to measure the gain in explanatory power. The results suggest that the role of infrastructure in employment growth rate is limited and varies according to economic sectors and network types.     

Dynamic location: an iconic model to synchronize temporal and spatial transportation data

This paper describes a model to synchronize the management and query of temporal and spatially referenced transportation data in geographic information systems (GIS). The model employs a method referred to as dynamic location, which facilitates spatial intersect queries from geographic shapes without the use of topological relationships. This is the inverse of how dynamic segmentation works in GIS. In contrast to dynamic segmentation, dynamic location stores geometry as an object within a single database field. This is an efficient, precise iconic model superseding the need for data decomposition into a complex set of tables. As an object model, the dynamic location process lends itself to high performance in an Internet, data-intensive, enterprise environment. Linear events are stored as {x, y} features, and not referenced to any route system. Route systems are built from {x, y, m} values (m for measure) and serve as number lines for mathematical operations. Any {x, y} object can then be referenced to either the Cartesian grid or any selected number line. This method offers the benefits of linear referencing, while making full use of a stable geodetic datum. Combinations of any {x, y} events may be placed over any {x, y, m} number line (route) and an intersect determined by looking through stacked {x, y, m} vertices of the coincident shapes. Since both geometry and shape reside in the same record, the use of “begin” and “end” dates facilitates full spatial and temporal version control. From a business process perspective, this creates a spatially enabled database, pulling GIS business functions back into the information technology mainstream.