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531.
The highest diversity coral reefs in the world, located in the Coral Triangle, are threatened by a variety of local stresses including pollution, overfishing, and destructive fishing in addition to climate change impacts, such as increasing sea surface temperatures (SSTs), and ocean acidification. As climate change impacts increase, coral reef vulnerability at the ecoregional scale will have an increasingly important influence on conservation management decisions. This project provides the first detailed assessment of past and future climatic stress, thermal variability, and anthropogenic impacts in the Coral Triangle at the ecoregional level, thus incorporating both local (e.g., pollution, development, and overfishing) and global threats (increasing SSTs). The development of marine protected area (MPA) networks across the Coral Triangle is critical for the region to address these threats. Specific management recommendations are defined for MPA networks based on the levels of vulnerability to thermal and local stress. For example, coral reef regions with potentially low vulnerability to thermal stress may be priorities for establishment of MPA networks, whereas high vulnerability regions may require selection and design principles aimed at building resilience to climate change. The identification of climate and other human threats to coral reef systems and ecoregions can help conservation practitioners prioritize management responses to address these threats and identify gaps in MPA networks or other management mechanisms (e.g., integrated coastal management).  相似文献   
532.
Climate change poses known and unknown risks for coastal communities and also challenges for university faculty and local government staff who communicate about cli- mate sciences. Conceived as a way to move beyond traditional models of science communication, this project involved public and private decision makers in specific at-risk communities in Oregon (U.S. Pacific coast) and Maine (Atlantic coast). Both state projects sought to move behavior toward decisive action that results in coastal communities that are more resilient to climate variability at all scales. To promote engagement between project staffs and publics, a dialogic model of communication was advanced, beginning with interviews and focus groups that in turn shaped further engagement through workshops and targeted video products. This means of communication led to a deeper understanding of participants’ knowledge, beliefs, perceptions, values, and barriers to action related to climate change and its effects. Coinciding with this, project participant evaluations in both Oregon and Maine indicate that the workshops and videos were successful at informing them on this complex issue; and in both states, project participation led to action outcomes. We believe that applied elsewhere our multifaceted and adaptive approach will garner similar results, provided sufficient dedicated staffing and attention to methods.  相似文献   
533.
轮胎式集装箱门式起重机节能技术应用与发展   总被引:5,自引:1,他引:5  
介绍当前国内外轮胎式集装箱门式起重机(RTG)的节能技术方案,分析RTG"油改电"应用的主要技术特点,指出RTG节能技术的发展方向。  相似文献   
534.
本文对美国破产立法的历史演变和未来走向作了简要的回顾和考察,并对历次演变及更迭的成因进行了简要的分析。文章第一部分回顾了美国破产法的历史沿革,第二部分分析了美国破产立法的演变特点及成因,第三部分审视了美国破产立法的现实走向。  相似文献   
535.
ABSTRACT

Stability control of a vehicle in autonomous safety-critical at-the-limit manoeuvres is analysed from the perspective of lane keeping or lane changing, rather than that of yaw control as in traditional ESC systems. An optimal control formulation is developed, where the optimisation criterion is a linear combination of the initial and final velocity of the manoeuvre. Varying the interpolation parameter in this formulation turns out to result in an interesting family of optimal braking and steering patterns in stabilising manoeuvres. The two different strategies of optimal lane-keeping control and optimal yaw control are shown to be embedded in the formulation and result from the boundary values of the parameter. The results provide new insights and have the potential to be used for future safety systems that adapt the level of braking to the situation at hand, which is demonstrated through examples of how to exploit theresults.  相似文献   
536.
Weaving sections, where a merge and a diverge are in close proximity, are considered as crucial bottlenecks in the highway network. Lane changes happen frequently in such sections, leading to a reduced capacity and the traffic phenomenon known as capacity drop. This paper studies how the emerging automated vehicle technology can improve the operations and increase the capacity of weaving sections. We propose an efficient yet effective multiclass hybrid model that considers two aspects of this technology in scenarios with various penetration rates: (i) the potential to control the desired lane change decisions of automated vehicles, which is represented in a macroscopic manner as the distribution of lane change positions, and (ii) the lower reaction time associated with automated vehicles that can reduce headways and the required gaps for lane changing maneuvers. The proposed model is successfully calibrated and validated with empirical observations from conventional vehicles at a weaving section near the city of Basel, Switzerland. It is able to replicate traffic dynamics in weaving sections including the capacity drop. This model is then applied in a simulation-based optimization framework that searches for the optimal distribution of the desired lane change positions to maximize the capacity of weaving sections. Simulation results show that by optimizing the distribution of the desired lane change positions, the capacity of the studied weaving section can increase up to 15%. The results also indicate that if the reaction time is considered as well, there is an additional combined effect that can further increase the capacity. Overall, the results show the great potential of the automated vehicle technology for increasing the capacity of weaving sections.  相似文献   
537.
结合实践经验,探讨了项目建设前期准备、项目实施过程中、项目完成后三个阶段的工程变更问题,从变更项目的前瞻性、熟悉变更文件、变更实施的可操控性、变更签认的及时性四个方面介绍了工程变更在项目管理中的应用。  相似文献   
538.
借助虚拟样机仿真技术,发现某预研项目车辆具有过多转向趋势,在全面分析车轴左右轮荷变化的基础上,深入探讨了车辆转向特性的影响因素.针对本项目提出可通过加粗前悬架横向稳定杆直径的办法来获得车辆的不足转向特性。通过对多种匹配方案的仿真分析和对比权衡,并结合国标对稳态回转实验的评价打分方法,最终确定把前后悬架侧倾角刚度之比由1.17增加到1.96,此时车辆的过度转向趋势得以消除,并具有了适度的不足转向特性。  相似文献   
539.
丁旭  王海晓  高明星  吕贞 《隧道建设》2022,42(4):679-687
公路隧道出入口段行车时驾驶员的视觉负荷变化较大,为进一步量化该路段视觉负荷的变化规律,选取10名驾驶员在秦岭终南山公路隧道柞水—西安段进行实驾试验,采集驾驶员在昼间晴朗天气下通过隧道出入口路段的照度、车速、瞳孔面积等数据。通过分析驾驶员在隧道出入口段的瞳孔面积变化特征,参照峰均比(PAR)、频段比(LF/HF)等物理学、医学参数,提出“瞳孔面积相对变化强度”(RCPA)的概念,将其作为视觉负荷的评价指标,划分出该指标取值与视觉舒适度的关系,并建立RCPA与速度、照度的数学模型。结果表明: 1)RCPA可以较好地体现出隧道出入口段视觉负荷渐变累积和急剧震荡的规律; 2)在即将驶入洞口和刚刚驶离洞口时的瞬时视觉负荷最大,超过了生理极限; 3)RCPA与速度、照度的定量关系可为隧道出入口制定安全速度阈值、改善照明环境提供参考依据。  相似文献   
540.
Magneticmotorevokedpotentialisanon-invasiveelectrophysiologictechnique,currentlyinuse,intheclinicaldiagnosisoftheextentofspin...  相似文献   
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