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91.
When Canadian salmon farmers find the health of their stock is compromised by infection or disease, the use of drugs or pesticides can be required. In Canada, there is a very limited range of these chemicals legally available to farmers and veterinarians. The formal approval and registration process for these chemotherapeutants is complicated. It involves the overlap of a variety of government departments, depending on the method of application of the therapeutic compound. These formal channels, through which chemotherapeutic products, specifically drugs and pesticides, are licensed for use, are both lengthy and costly to navigate. Often, these costs exceed any potential returns from the sale of the products (OCAD, 2001; Harper, 2002). Consequently, unapproved drugs, which would not normally be available for use, are obtained through alternative channels, which may pose a number of environmental, human, and animal safety concerns. This article seeks to provide a better understanding of the approval process and regulations governing drugs and pesticides and how they are made available for use in Canadian salmon culture.  相似文献   
92.
Many marine protected areas (MPAs) face a multitude of threats to the ecosystems that they have been established to conserve. This study is based on 111 interviews conducted in 2013–2014 designed to discover the perceptions of stakeholders about the threats, the causes of the threats, and their responses to the threats, to a well-established MPA – Cabo de Palos - Islas Hormigas (CPH-MPA). This MPA was created to safeguard fisheries and the associated artisanal fishers, but over time it has become a tourism “hotspot.” Resilience theory, which incorporates ecological resilience, social resilience, and individual resilience, helps us to analyze stakeholders' responses to threats by categorizing them into passive, adaptive, and transformative responses. We found respondents identified four main threats – over-fishing, excessive scuba diving, pollution, and invasive species; attributed the threats to three main causes – ineffective management, poor environmental stewardship, and climate change; and expressed three kinds of responses – do nothing, adapt, or transform – with a preference for adaptation and (especially) transformation. The lesson of this study is that it shows how, unless drastic action is taken to curb recreational diving activities, the CPH-MPA is in danger of changing from a fishing reserve to a largely unregulated leisure diving venue, which is unlikely to fulfill the requirements of resilience; ecological, social, or individual.  相似文献   
93.
采用降雨极值的皮尔逊-Ⅲ型分布模型,引入冯利华干旱模型,分析基于马尔可夫链的晴雨转化矩阵.并通过这些概率模型建立膨胀土路基在气候作用下的水毁灾害预测模型.计算分析结果表明,该计算模型为膨胀土路基的地理分布与气候耦合时的水毁预测提供了一种可扩展的算法,也可用于极端气候条件下的其他灾害预测.  相似文献   
94.
为满足TB 10601-2009《高速铁路工程测量规范》中控制网设计时边长投影变形值的要求,设计院通常把1条几百公里的高速铁路划分为多个几十公里的工程投影独立坐标系。相邻坐标系之间的搭接段线路设计中线,可采用前、后投影带坐标系的设计参数来推算,由于投影变形导致相邻坐标系推算出的线路设计中线存在横向偏差,轨道精调时若处理不当,会降低轨道的平顺性,甚至影响运营铁路的行车安全。为解决换带搭接段设计中线的横向偏差,提高轨道精调的效率及精度,本文提出利用方向自适应投影将运营铁路多个坐标系统一为1个坐标系的方法,同时建立精确的线路参数转换模型,实现了原设计参数与新设计参数的精确转换。通过工程实例验证,坐标系统一后的线路参数与原设计参数较差较小,不会影响轨道平顺性,该方法可行。研究成果可为提升运营铁路精调效率提供借鉴。  相似文献   
95.
地铁司机职业适应性测试管理实验系统设计   总被引:1,自引:0,他引:1  
在对地铁司机的职业进行分析研究的基础上,研制了地铁司机职业适应性测试管理实验系统.介绍了系统的总体结构、后台数据库设计、前后台交互式界面处理流程,以及系统各模块的功能.该系统采用浏览器/服务器结构,包括测试信息管理、系统维护及职业适应性测试等三个子系统.系统能够生成测试试题并记录测试结果,同时可根据相关的评价指标进行处理,对地铁司机的职业适应性做出量化评判,从而为地铁司机的安全值乘、合理选拔提供科学依据.  相似文献   
96.
Climate change is predicted to have particularly challenging impacts throughout the Arctic. For instance, there is a great probability of sea ice melting, leading to increased vessel traffic and oil pollution. Eight major nation-states have vested concerns in the potential opening of Arctic sea routes. They each have pledged to take protective action through the Arctic Council. However, there is still a need to develop an international institution to simultaneously address Arctic marine pollution and protect the needs of these states. This article seeks to design a legally binding regime for oil pollution control in the Arctic. In creating this new regime, we shall utilize several shared design elements of historically effective international regimes and take advantage of the legal innovations of these agreements. Our new regime, entitled the Arctic Shipping and Environmental Management Agreement (ASEMA), will take into account both the economic and environmental interests of the parties involved.  相似文献   
97.
Four decades ago Australia was credited as being an early leader in implementing integrated coastal management (ICM). Nevertheless, as a federation of states and territories Australia has since struggled to fully implement vertical integration of its coastal governance arrangements. In particular the federal government has historically possessed only a minor role in coastal management despite the recommendations of several major inquires suggesting that this role needed to be enhanced. This article examines a series of circumstances and events over the past two years in Australia that has created the opportunity for the federal government to adopt a more significant and prominent role in coastal management and hence to substantially complete the vertical integration of ICM in Australia. These stimuli for coastal policy reform could also play a role in enhancing ICM in other federated nations.  相似文献   
98.
Climate change is having and will continue to have a range of negative impacts on social–environmental systems. Many ports, with their coastal locations and essential roles in regional and national economies, face particular exposure to storm impacts that may worsen with climate change. Currently in the United States port resilience planning falls primarily on port operators. Engaging a wider range of stakeholders in long-term seaport functioning may reduce risks from disruptive and potentially irreversible impacts of climate change. This study uses empirical data gathered through two case studies of highly exposed U.S. ports, Gulfport (MS) and Providence (RI), to identify strategies that port planners and external stakeholders consider feasible for enhancing their port's resilience. This article categorizes these resilience strategies and suggests the potential role that different stakeholders could play in facilitation and implementation.  相似文献   
99.
This contribution addresses the need for a simple model for managers to employ when planning strategies for the management of touristic beaches under sea level rise. A methodological framework was developed and tested in two Aegean archipelago islands (Lesvos and Rhodes, Greece). The scheme can represent the status of touristic island beaches, based on easily obtained variables/indicators and projections of beach erosion/retreat under different scenarios of mean sea level rise (MSLR) and extreme events. Information on beach geomorphological characteristics, environmental setting, water quality, management, and services (such as those used in the “Blue Flag” classification) was collated/collected and beach erosion/retreat due to CV & C was estimated through suitable ensembles of cross-shore (1-D) morphodynamic models. A Strength-Weaknesses-Opportunities-Threats (SWOT) framework was employed to assist in the selection of indicators and multicriteria analysis used to optimize indicator weights and rank beaches according to their sustainability under sea level rise. Implementation of the framework at the two islands has shown that: the majority of Lesvos and Rhodes beaches (82% of a total of 217 beaches and 58% of a total of 97 beaches, respectively) can be classified as beaches with no, or minimal, human interference, suggesting that under environmentally sound coastal management further touristic development might be afforded; there could be very significant effects of the sea level rise on the carrying and buffering capacities of the most developed (“Blue Flag”) beaches, with some expected even under conservative projections to be completely eroded by 2100, unless technical adaptation measures are taken; and using the proposed framework, touristic beaches can be rapidly ranked in terms of their resilience to sea level rise and their development potential, allowing prioritization of effective management responses.  相似文献   
100.
In this paper, we investigate an area-based pricing scheme for congested multimodal urban networks with the consideration of user heterogeneity. We propose a time-dependent pricing scheme where the tolls are iteratively adjusted through a Proportional–Integral type feedback controller, based on the level of vehicular traffic congestion and traveler’s behavioral adaptation to the cost of pricing. The level of congestion is described at the network level by a Macroscopic Fundamental Diagram, which has been recently applied to develop network-level traffic management strategies. Within this dynamic congestion pricing scheme, we differentiate two groups of users with respect to their value-of-time (which related to income levels). We then integrate incentives, such as improving public transport services or return part of the toll to some users, to motivate mode shift and increase the efficiency of pricing and to attain equitable savings for all users. A case study of a medium size network is carried out using an agent-based simulator. The developed pricing scheme demonstrates high efficiency in congestion reduction. Comparing to pricing schemes that utilize similar control mechanisms in literature which do not treat the adaptivity of users, the proposed pricing scheme shows higher flexibility in toll adjustment and a smooth behavioral stabilization in long-term operation. Significant differences in behavioral responses are found between the two user groups, highlighting the importance of equity treatment in the design of congestion pricing schemes. By integrating incentive programs for public transport using the collected toll revenue, more efficient pricing strategies can be developed where savings in travel time outweigh the cost of pricing, achieving substantial welfare gain.  相似文献   
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