Influence of Trampling Intensity versus Hydration State on Loss of Biomass from the Intertidal Rockweed,Fucus gardneri

I investigated the impact of human trampling on Fucus gardneri populations at Cattle Point on San Juan Island, Washington. I hypothesized that damage to Fucus fronds would differ depending on hydration state of the plants, number of trampling steps, and time. Over a two-day period, two levels of trampling treatment, 100- and 200-steps, were applied to 18 plots on two rocky intertidal benches. Detached biomass resulting from trampling was collected each day, weighed to the nearest 0.1 gram, re-hydrated overnight in seawater, and re-weighed in order to calculate biomass removed as a function of mean percent Fucus within each plot. Damage to plants did not differ with the hydration state of Fucus. However, loss of biomass did increase with treatment level, with 222 g of Fucus fronds removed from one 100-step plot up to 1302 g removed from a 200-step plot. Percent cover decreased differentially with treatment level, ranging from 10 percent cover in a 100-step plot up to 85 percent loss in a 200-step plot. To determine the effect of hydration on loss of Fucus biomass, future studies should include plants with a higher degree of desiccation than those in this study, more samples to increase the power of the analysis, and a longer period to detect changes due to time.     

Caught in a Maelstrom: Implementing California Marine Protected Areas

The first attempt to implement the 1999 California Marine Life Protection Act (MLPA) to establish marine protected areas (MPAs) ended contentiously in 2002. The initial MLPA process is examined by a statutory analysis and an analysis of stakeholder network relationships and beliefs. The failure of the initial MLPA process can be understood by a combination of factors: (i) Insufficient financial support from the California State government; (ii) Unclear, unranked and inconsistent statutory objectives; (iii) The application of a science-based process that excluded affected stakeholders; (iv) Implementing officials who lacked expertise in designing and managing political processes; and (v) A community of stakeholders who were polarized into coalitions of proponents and opponents of MPAs. The article concludes by discussing limitations of its methods and analysis and by offering strategies for learning from policy failures.     

Management considerations for accreting shorelines

Abstract

Natural coastal accretion in the United States occurs at river mouths, spits across embayments, inlets, capes and cuspate forelands, and pocket beaches. Human‐induced accretion occurs updrift of groins and jetties, landward of breakwaters, and in locations which are artificially nourished. Coastal accretion is usually temporary (years to tens of years). Erosion may occur due to deflection of streams and tidal current channels or to changes in sea level, weather patterns, or sediment budgets. A focus on ownership disputes or use of accreted land draws attention away from the long‐term problem of the development of land which may be subject to future erosion. Control mechanisms should be in place to direct development on accreting shorelines to make more effective use of the resource.     

平阳高速公路穿越东村小窑煤矿采空区设计

近年来山西省的高速公路穿越煤矿采空区和铝土矿采空区的工程很多,采空区的处治设计直接影响到高速公路的运营安全和使用寿命。结合工程实践,针对平阳高速公路煤矿采空区的特点,阐述穿越东村小窑煤矿采空区的三种处治设计方案,并对方案进行对比,可供同行参考。     

民族地区高职高专院校贫困生现状调查分析——以L高等专科学校为例

由于我国各地区地理位置、经济发展状况不一样,民族地区高职高专院校学生贫困生所占的比例相对比较多。文中拟对高职高专院校贫困生在校表现做一个深入调查和分析,为民族地区高职高专院校贫困生学生思想工作提供相应的对策。     

夏热冬冷地区重交通钢桥面铺装技术应用

夏热冬冷地区重交通钢桥面铺装对钢板防护、混合料高温稳定性和低温抗裂性要求较高,同时需兼顾沥青混合料的耐久性和施工和易性。通过对全国典型钢桥面铺装的调研和分析,判断沙尔沁互通立交钢桥面浇注式沥青混凝土铺装设计的合理性,通过关键施工控制措施,使该种铺装结构在沙尔沁互通立交顺利实施。     

黄土地区高陡斜坡溜坍下滑治理研究

根据黄土高陡斜坡溜坍下滑的现状、特点、地质情况等,应用预应力锚索锚固桩预加固坡脚,通过检算各级边坡的最不利圆弧滑动面,设置锚索格梁、十字形锚杆格梁加固防护各级边坡,可有效治理高陡斜坡的溜坍下滑。研究阐明本项目的边坡设计参数、设计检算与工程设置情况,为类似工程设计提供参考。     

城市轨道交通控制保护区管理要点

如果因城市轨道交通控制安保区管理难度及协调难度加大造成监管不到位,将存在影响运营安全甚至出现停运的风险。分析轨道交通控制保护区事故出现的位置及发生的原因,通过对运营线路控制保护区施工项目进行技术审查、过程监管,做到将控制保护区的安全影响因素降到最低,规范控制保护区的技术方案及施工方法,确保各项安全措施落实。实践证明,这些要点是对轨道交通安全防护的重要举措。     

Analysis on Gas Characteristics of the Sichuan Red-bed Section of ChengduGuiyang Railway and Suggestion on Division of Gas Working Areas in the Survey Stage北大核心CSCD

Combining with the borehole gas concentration tests for the Sichuan red-bed section of the Chengdu-Guiyang Railway, this paper analyzes its correlation with the stratum chronology geological structure, and tunnel depth on the basis of data statistics, and puts forward the suggestion to qualitatively and quantitatively divide gas working areas. The results show that the correlation between the tunnel gas concentration and the stratum chronology is not significant in the Sichuan red-bed section of the Chengdu-Guiyang Railway (except coal-bearing strata); geological structure plays a controlling role in gas transport and accumulation; and the positive correlation between the gas concentration and the tunnel depth is significant. According to the above conclusions, it could qualitatively divide the gas working areas according to the geological structure and mapping information collected during the survey stage, and quantitatively divide the gas working areas according to the gas concentration test results. The final categorization of gas working areas can be determined by combining the qualitative and quantitative results. © 2022, Editorial Office of "Modern Tunnelling Technology". All right reserved.