Tracking a half century of media reporting on gray wolves

Natural resource and wildlife managers must balance the disparate priorities of a diversity of stakeholders. To manage these priorities, a firm understanding of topics salient to the public is needed. The media often report on issues of importance to the public; therefore, these reports may be a useful measure of public interest. However, efficient methods for distinguishing diverse topics related to a wildlife management issue reported in the media and changes in the salience of those topics have been lacking. We used latent Dirichlet allocation, a Bayesian mixture model, to quantitatively assess the salience of topics surrounding the gray wolf (Canis lupus), which was reintroduced to Idaho (U.S.A.) in 1995. We analyzed articles published from 1960 to 2015 in an Idaho newspaper. We identified 6 distinct topics associated with gray wolves: policy, hunting, biological status, implementation of management, recovery, and human-wolf conflict. The salience of topics pre- and postreintroduction of wolves (1995) and pre- and postdelisting of wolves from the U.S. Endangered Species Act (2009) differed significantly, underscoring that these events were turning points in how issues were being publicly discussed and framed. Articles written by the local reporters were more likely to report on topics regarding conflict between humans and wolves, whereas articles sourced from a national outlet reported more on topics pertaining to wolf policy and biological status. In the context of managing a contentious, far-ranging, and long-lived wildlife species, our methods can help guide the location and timing of a suite of management strategies (e.g., media relation plans and stakeholder engagement) that promote human-wildlife coexistence across different landscapes.     

驾驶员风险认知能力对交通安全的影响

为辨别不同驾驶员风险认知能力对驾驶安全的影响。通过设置13种存在潜在风险的交通情景,引入惩罚用时机制,利用驾驶模拟器,对熟练驾驶员和非熟练驾驶员在风险认知培训前后的风险认知能力进行比较,找出不同驾驶员对风险认知的差异。试验结果显示,熟练驾驶员的风险认知能力比非熟练驾驶员要高,两者在引起交通风险的因素上是不同的,培训后的风险认知能力较之前有很大提高。培训能够拓宽驾驶员对潜在风险的认知程度,更好地将驾驶员的操作技能、知识体系和外在行为衔接在一起,从而减少交通事故的发生。     

An investigation on the fuel savings potential of hybrid hydraulic refuse collection vehicles

Refuse trucks play an important role in the waste collection process. Due to their typical driving cycle, these vehicles are characterized by large fuel consumption, which strongly affects the overall waste disposal costs. Hybrid hydraulic refuse vehicles offer an interesting alternative to conventional diesel trucks, because they are able to recuperate, store and reuse braking energy. However, the expected fuel savings can vary strongly depending on the driving cycle and the operational mode. Therefore, in order to assess the possible fuel savings, a typical driving cycle was measured in a conventional vehicle run by the waste authority of the City of Stuttgart, and a dynamical model of the considered vehicle was built up. Based on the measured driving cycle and the vehicle model including the hybrid powertrain components, simulations for both the conventional and the hybrid vehicle were performed. Fuel consumption results that indicate savings of about 20% are presented and analyzed in order to evaluate the benefit of hybrid hydraulic vehicles used for refuse collection.     

PLC控制系统在钢渣热焖工艺中的应用

利用PLC控制系统,实现在钢渣热焖工艺中的恒压供水和钢渣热焖定时定量喷水的自动控制要求,具有国际先进水平,取得了良好的经济效益、社会效益和环境效益.     

分子生物学技术在水处理中的应用研究进展

利用现代分子生物学技术对微生物进行分析和研究,以解决传统微生物分析成本高、速度慢、准确度较低和灵敏度较差等缺点。介绍分子生物学技术在水处理中的应用现状,并对未来发展方向提出建议。目前分子生物学技术在供水工程中主要用于水中细菌、病毒、原生动物、蠕虫等病原微生物的快速检测以及管网微生物种群的分析,在污水处理中主要用于脱氮除磷过程菌群数量和空间分布的剖析、污泥膨胀成因分析以及监测微生物种群多样性来优化处理工艺。分子生物学技术的深入研究将进一步促进水行业的发展。     

Effects of sludge retention time, carbon and initial biomass concentrations on selection process: From activated sludge to polyhydroxyalkanoate accumulating cultures

Four sequence batch reactors (SBRs) fed by fermented sugar cane wastewater were continuously operated under the aerobic dynamic feeding (ADF) mode with different configurations of sludge retention time (SRT), carbon and initial biomass concentrations to enrich polyhydroxyalkanoate (PHA) accumulating mixed microbial cultures (MMCs) from municipal activated sludge. The stability of SBRs was investigated besides the enrichment performance. The microbial community structures of the enriched MMCs were analyzed using terminal restriction fragment length polymorphism (T-RFLP). The optimum operating conditions for the enrichment process were: SRT of 5 days, carbon concentration of 2.52 g COD/L and initial biomass concentration of 3.65 g/L. The best enrichment performance in terms of both operating stability and PHA storage ability of enriched cultures (with the maximum PHA content and PHA storage yield (Y_PHA/S) of 61.26% and 0.68 mg COD/mg COD, respectively) was achieved under this condition. Effects of the SRT, carbon concentration and initial biomass concentration on the PHA accumulating MMCs selection process were discussed respectively. A new model including the segmentation of the enrichment process and the effects of SRT on each phase was proposed.     

航空装备外场级平均修复时间评估研究

目的探索航空装备部队使用保障阶段维修性指标评估的实施方法。方法构建航空装备外场级平均修复时间评估指标体系,包括评估条件界定、统计准则确定、数据处理方法、评估流程、使用表格等,并结合具体机型进行评价应用。结果该机型飞机整机的累计修复时间为138.5 h,平均修复时间Mct=2.17 h,满足不大于3 h指标要求。结论评估方法系统科学,可为各类装备开展相关维修性评估工作提供方法支持和工程借鉴。     

机载武器及其双配套设备可靠性鉴定试验方案的分析

通过分析机载武器的使用特点和情况,并结合实验室开展机载武器可靠性鉴定试验的已有经验,对该类装备的可靠性鉴定试验的方案进行了分析和讨论,对试验样件在充足或不足的条件下进行试验的各种试验方案进行了深入分析。指出了各种方案的优缺点,对比了各种试验方案的特点。最后给出了机载武器可靠性鉴定统计试验方案的选取原则。     

生态高负荷土地快速渗滤系统处理猪场废水的效能及微生态

以经过厌氧反应器处理后的猪场废水为研究对象,探讨了新型生态高负荷土地快速渗滤系统对废水中COD、氨氮及总氮的去除情况;同时分析了该系统中的微生物群落结构以及过氧化氢酶、脲酶、硝酸盐还原酶的含量.结果表明,在水力负荷为11 cm·d~(-1)、进水COD为700 mg·L~(-1)左右的条件下,一级土地渗滤柱与二级土地渗滤柱对COD的去除率分别为78.8%与63.0%,总去除率达到了92.6%;而当水力负荷增大到22 cm·d~(-1)时,总的COD去除率仍在90.0%以上;该系统对于氨氮的去除更为显著,去除率可达99%左右.一级土地快速渗滤系统中上、中、下部的过氧化氢酶含量分别为1.899、0.990、0.323 m L·g~(-1),表明猪场废水中的有机物主要在该系统的上部与中部得以去除;二级土地快速渗滤系统上、中、下部的硝酸盐还原酶含量分别是3.453、3.831、1.971 m L·g~(-1),表明脱氮作用主要发生二级土地快速渗滤系统的上部与中部.该土地快速渗滤系统中微生物以Gram Negative与Gram Positive为主,特别是在二级土地快速渗滤系统中,AM Fungi与Actinomycetes占有一定比例,为猪场废水中难降解有机物的去除提供了保障.     

海水生物滤器氨氮沿程转化规律模型

生物滤器是海水循环水养殖系统中的核心水处理单元,其主要用于去除对养殖生物有害的氨氮、有机物等.本研究基于吸附原理和一级反应生物膜理论构建了氨氮在生物滤器中沿程转化规律的数学模型,并通过实验加以验证.实验所用生物滤器采用竹制空心生化球填料,装填高度为70 cm,在pH为7.1～7.6,DO为5～7 mg.L-1,气水比20∶1左右,有机负荷约为4g.(m3.h)-1,水力停留时间(HRT)为1 h条件下,生物滤器中氨氮的去除主要发生在填料高度0～10 cm处,10～70 cm处氨氮去除量很少.进水氨氮质量浓度的增大和水力停留时间的降低都会导致出水氨氮质量浓度增大.此外,模型对进水氨氮质量浓度较低时的沿程出水氨氮质量浓度具有很好的预测效果;当进水氨氮质量浓度较高时,预测值略低于实际结果.