基于遗传-神经网络算法的含均匀腐蚀缺陷油气管线爆破压力预测研究*

为提高含均匀腐蚀缺陷油气管线爆破压力的预测精度，保障长输油气管线的安全运行，将遗传算法和BP神经网络相结合，建立含均匀腐蚀缺陷油气管线爆破压力预测的遗传-BP神经网络（GA-BPNNs）模型。采用已有文献实验数据，分析对比该模型与AGA NG-18，ASME B31G，修正B31G，PCORRC，DNV RP-F101和SHELL 92等方法用于X46，X52，X60，X65，X80等材质油气管线含均匀腐蚀缺陷时爆破压力的计算误差。结果表明:GA-BPNNs模型用于含均匀腐蚀缺陷油气管线爆破压力预测时，误差在-7.78%～6.06%之间，预测精度明显高于目前国内外通用规范的计算结果；该模型操作简单，适用范围广，工程实用性好，为含缺陷压力管道爆破压力的预测提供更好的思路和方案。     

Role of Genetic Refuges in the Restoration of Native Gene Pools of Brown Trout

Abstract:  Captive-bred animals derived from native, alien, or hybrid stocks are often released in large numbers in natural settings with the intention of augmenting harvests. In brown trout ( Salmo trutta ), stocking with hatchery-reared non-native fish has been the main management strategy used to maintain or improve depleted wild brown trout populations in Iberian and other Mediterranean regions. This measure has become a serious threat to the conservation of native genetic diversity, mainly due to introgressive hybridization. Aware of this risk, the agency responsible for management of brown trout in the eastern Pyrenees (Spain) created "brown trout genetic refuges" to preserve the integrity of brown trout gene pools in this region. Within refuge areas, the prerefuge status with respect to fishing activities has been maintained, but hatchery releases have been banned completely. We evaluated this management strategy through a comparison of the stocking impact on native populations that accounted for stocking histories before and after refuge designations and fishing activities. In particular we examined the relevant scientific, cultural, and political challenges encountered. Despite agency willingness to change fishery policies to balance exploitation and conservation, acceptance of these new policies by anglers and genetic monitoring of refuge populations should also be considered. To improve management supported by genetic refuges, we suggest focusing on areas where the public is more receptive, considering the situation of local native diversity, and monitoring of adjacent introgressed populations. We recommend the use of directional supportive breeding only when a population really needs to be enhanced. In any case, management strategies should be developed to allow for protection within the context of human use.     

初中教育师资力量与教育成效耦合协调研究--以大连市为例

基于2015年大连市初中学校教育统计数据,利用熵值法、耦合协调度模型和空间插值分析法,从市域内校际间对大连市初中师资力量与教育成效耦合协调的空间特征进行了研究。结果表明:①师资力量高低分离、抱团分布,教育成效呈现核心高、边缘低的格局。②师资力量与教育成效的耦合度总体水平较高,以高水平耦合为主,空间上基本覆盖整个大连市。③协调度上,勉强协调与初级协调为主,空间呈现明显的中心—外围分布趋势,其中勉强协调占大部分。④学校类型具体划分为6种协调类型,呈核心—外围的圈层分布模式,其中核心城区为师资高成效高的中级协调。     

Welfare effects of rural-urban land conversion on different aged land-lost farmers: exemplified in Wuhan city

Rural-urban land conversion is a universal phenomenon in the rapid process of economic development and urban growth. The welfare of farmers who lost their farmland attracted a widespread concern within the society and academia. However, further research about differentiated policies according to the characteristics of different farmer groups is still need to be conducted. This article divides the land-lost farmers into three age groups: younger than 45, 45–65, and more than 65. It proposes a welfare index system including eight functional areas based on different age groups of affected farmers, taking four districts of Wuhan City as case study area. Fuzzy mathematics method is used to derive the aggregated welfare effect index. Our analysis show that the overall welfare levels of land-lost farmers of all age groups declined, but with a varying degree, with the level of welfare in those farmers who are 45–65 years old, younger than 45 years old, and older than 65 years old decreased by 18.7%, 16.6%, and 12.7%, respectively. The direction and degree of effects on the functional activity index varies among different groups. Economic conditions, living environment, health, and social participation of all age groups decrease while social security and housing conditions increase. On the other hand, development opportunities, social communication, and leisure have different changing directions in different age stages. These results call for differentiated and tailor-made compensation policies for land-lost farmers, towards improving the welfare levels of all farmers and reduce the disparity among them.     

高层RC框架结构基于成本-效益准则的优化设计研究(Ⅱ)——应用

根据作者先前提出的优化模型及基于成本-效益准则的优化设计流程,以多目标遗传算法为搜索引擎,运用MATLAB语言开发了高层RC框架结构基于成本-效益准则的自动优化程序。研究结果表明,程序所产生的设计方案具有多样性、可选择性、业主主动参与性及可依靠经验等特点。     

An emergency response plan for cascading post-earthquake fires in fuel storage facilities

Natural disasters such as large earthquakes may rapidly result in cascading events such as post-earthquake fires (PEFs) to trigger. This is particularly the case in industrial facilities which is well known as natural-hazard triggered technological accidents (NaTechs). This study provides a response framework for NaTechs caused by earthquake in fuel storage facilities. To do this, seismic vulnerability of fuel storage tanks and possible damage fashions are studied. Considering fuel leakages can result in PEFs, possible scenarios are simulated numerically using Process Hazard Analysis Software Tool (PHAST). A case study including 20 fuel tanks adjacent one to another is investigated to simulate a domino effect when different arbitrary tanks start to ignite; hence, the worst case scenario can be determined. Based on the results of the case studied, inability to extinguish the possible PEFs over less than 9 min can lead to spreading them to the adjacent tanks. The results indicate that it takes about 40 min the adjacent tanks involve in the fires. Therefore, it is of paramount importance to provide an emergency response plan in advance to properly respond to the fires. The study here also highlights the role of preventive strategies in reducing the associated risks of PEFs in industrial facilities.     

Ability of Wildlife Overpasses to Provide Connectivity and Prevent Genetic Isolation

Abstract:  We reviewed research on wildlife overpasses in the context of their genetic effectiveness to provide connectivity between population patches that have been isolated by road construction. The potential ecological consequences of such habitat fragmentation include reduction of gene flow between subpopulations and hence an increase in genetic differentiation and a decrease in genetic diversity. Among the solutions to provide connectivity between patches isolated by roads, wildlife overpasses are one of the most expensive alternatives. Despite the high costs associated with their construction, most of the studies assessing their use by wildlife remain observational, reporting evidence for passage use but few data on the number of individual crossings. Moreover, the use itself of wildlife overpasses does not appear sufficient to assess their effectiveness from a genetic viewpoint because a minimum number of individuals is required to assure gene flow between population patches and because the spatiotemporal dimension of individual movements and demographic parameters of subpopulations must be considered. So far, there is no evidence that wildlife overpasses do or do not efficiently address genetic issues. This lack of data is probably due to the fact that few mitigation efforts have implemented monitoring programs that incorporate sufficient experimental designs into pre- and postconstruction evaluation. To assess the genetic effectiveness of wildlife overpasses, long-term monitoring programs, including fieldwork and genetic analyses, are needed.     

Ethical Considerations at the Various Stages in the Development, Production, and Consumption of GM Crops

The aim of this paper is to clarify the ethical issuessurrounding GM crops by examining the various stages or levels intheir development, production, and consumption. Previous workabout the acceptability or non-acceptability of GM crops hastended to conflate these various levels, partly as a result ofwhich GM crops are all-too-often simply said to be ``good' or``bad.' There are, though, various problems with such a binarycategorization. I look in particular at the duties of scientists,companies, regulatory systems, farmers, retailers, and consumers.