Improving credibility and transparency of conservation impact evaluations through the partial identification approach

The fundamental challenge of evaluating the impact of conservation interventions is that researchers must estimate the difference between the outcome after an intervention occurred and what the outcome would have been without it (counterfactual). Because the counterfactual is unobservable, researchers must make an untestable assumption that some units (e.g., organisms or sites) that were not exposed to the intervention can be used as a surrogate for the counterfactual (control). The conventional approach is to make a point estimate (i.e., single number along with a confidence interval) of impact, using, for example, regression. Point estimates provide powerful conclusions, but in nonexperimental contexts they depend on strong assumptions about the counterfactual that often lack transparency and credibility. An alternative approach, called partial identification (PI), is to first estimate what the counterfactual bounds would be if the weakest possible assumptions were made. Then, one narrows the bounds by using stronger but credible assumptions based on an understanding of why units were selected for the intervention and how they might respond to it. We applied this approach and compared it with conventional approaches by estimating the impact of a conservation program that removed invasive trees in part of the Cape Floristic Region. Even when we used our largest PI impact estimate, the program's control costs were 1.4 times higher than previously estimated. PI holds promise for applications in conservation science because it encourages researchers to better understand and account for treatment selection biases; can offer insights into the plausibility of conventional point‐estimate approaches; could reduce the problem of advocacy in science; might be easier for stakeholders to agree on a bounded estimate than a point estimate where impacts are contentious; and requires only basic arithmetic skills.     

Drying of combustible powders – Risk & mitigation

This paper provides an overview of the various processes for drying combustible powders with particular emphasis on spray, fluid bed and ring dryers. Clients of FM Global, an industrial property insurance company, have experienced numerous explosion and fire losses in dryers and the primary causes and equipment involved in recent events are reviewed. Several case examples are provided. Key operating parameters that can impact the hazard created by processing combustible dusts are highlighted. For each dryer type the key controls, alarms and interlocks are addressed as well as the protection and mitigation features that can be installed. This will emphasize FM Global loss prevention guidelines but will also point out differences with NFPA and EU codes.     

污染物与生物大分子作用的研究方法及进展

环境污染物进入机体后会首先作用于生物大分子,致使生物大分子的结构发生变化,从而产生一系列的病变作用,因此研究污染物与生物大分子之间的作用有助于深入地阐述污染物的致毒过程,从而全面评价环境污染物的毒性。近年来较常用于研究分子间相互作用的方法有荧光光谱法、平衡透析法、等温滴定微量热法、圆二色谱法、核磁共振、共振光散射等,本文对这些方法在研究污染物和生物大分子之间的结合模型、结合数目、结合位点等方面的研究成果进行了综述,并提出了今后的研究方向。     

耕作方式对太湖地区冬小麦生长季N_2O排放的影响

采用静态暗箱-气相色谱法对2009年11月至2010年6月冬小麦(Triticum aestivum L.)生长季N2O排放通量进行田间原位观测,研究不同耕作方式(免耕、少耕、传统耕作)对太湖地区稻麦轮作系统麦季土壤N2O排放的影响。结果表明:有植株参与下免耕、少耕和传统耕作的冬小麦生长季N2O平均排放通量分别为63.75μg·m-2·h-1、39.94μg·m-2.h-1和48.83μg·m-2·h-1,无植株参与下分别为73.48μg·m-2·h-1、52.97μg·m-2·h-1和63.60μg·m-2·h-1,麦季N2O排放通量的季节变化与5 cm、10 cm土壤温度呈显著或极显著线性正相关(r=0.400*～0.654**,n=28)。小麦种植对N2O的排放影响较大,无植株参与的N2O季节总排放量显著高于有植株参与的处理(P<0.05);耕作方式显著影响冬小麦农田N2O季节总排放量(P<0.05),有植株参与下麦季N2O总排放量少耕较免耕和传统耕作分别减少37.3%和17.9%,无植株参与下分别减少28.0%和16.7%。研究表明太湖地区冬小麦采用少耕措施可减少麦季N2O的排放。     

Suggestion on further strengthening ultra-low emission standards for PM emission from coal-fired power plants in China

China has established the largest clean coal-fired power generation system in the world by accomplishing the technological transformation of coal-fired power plants(CFPPs) to achieve ultra-low emission. The potential for further particulate matter(PM) emission reduction to achieve near-zero emission for CFPPs has become a hotspot issue. In this study,PM emission from some ultra-low emission CFPPs adopting advanced air pollutant control technologies in China was reviewed. The results revealed tha...     

同位素稀释-液相色谱-串联质谱法同时测定养殖水体中23种镇静剂

建立了同位素稀释-液相色谱-串联质谱法（LC-MS/MS）同时测定养殖水体中23种镇静剂残留的方法。样品经0.45 μm滤膜过滤后,用Oasis HLB固相萃取柱净化,浓缩后用50%的甲醇水定容。以1%甲酸水溶液和乙腈为流动相,采用Agilent InfiniityLab Poroshell 120 SB-C18色谱柱分离后,在多反应监测模式下测定,内标法定量。结果表明,23种镇静剂在0.5～100ng/L质量浓度范围内线性关系良好（r>0.99）,检出限和定量限分别为0.1~0.3和0.4 ~1.0 ng/L。加标回收率为73.5%~117.6%,相对标准偏差（RSD）为1.1%~9.9%。该方法前处理简单,净化效果较好,灵敏度较高,适用于池塘养殖水体中23种镇静剂类药物残留的快速检测。     

两种铁改性生物炭对微碱性砷镉污染土壤的修复效果

改性生物炭作为良好的重金属钝化剂,已被广泛应用于环境修复.为探究不同改性方法对生物炭钝化土壤砷-镉(As-Cd)的影响,采用共沉淀法和浸渍热解法制备铁改性生物炭,通过吸附试验和土壤培养试验,对生物炭性质、吸附As-Cd以及钝化土壤As-Cd的能力进行分析.结果表明,两种改性方法均可提高生物炭铁含量和零电荷点,且共沉淀法制备的铁改性生物炭(FeBC-1)负载的铁矿物主要为Fe₃O₄、 FeO(OH)和γ-Fe₂O₃等,而浸渍热解法制备的铁改性生物炭(FeBC-2)主要为α-Fe₂O₃和γ-Fe₂O₃等铁氧化物.FeBC-1对As和Cd均展现出很强的吸附去除能力,去除率达21.40%～34.14%,可显著促进土壤中非专性吸附态As向残渣态As转化,而FeBC-2仅对As具有较好的吸附效果.BC、 FeBC-1和FeBC-2对Cd的吸附能力与自身的阳离子交换量(CEC)呈正比,其中,BC对Cd的吸附去除效果优于FeBC...     

Creating Pedestrian Crash Scenarios in a Driving Simulator Environment

Objective: In 2012 in the United States, pedestrian injuries accounted for 3.3% of all traffic injuries but, disproportionately, pedestrian fatalities accounted for roughly 14% of traffic-related deaths (NHTSA 2014 NHTSA. Traffic Safety Facts 2012 Pedestrians. Washington, DC: Author; 2014. DOT HS 811 888. [Google Scholar]). In many other countries, pedestrians make up more than 50% of those injured and killed in crashes. This research project examined driver response to crash-imminent situations involving pedestrians in a high-fidelity, full-motion driving simulator. This article presents a scenario development method and discusses experimental design and control issues in conducting pedestrian crash research in a simulation environment. Driving simulators offer a safe environment in which to test driver response and offer the advantage of having virtual pedestrian models that move realistically, unlike test track studies, which by nature must use pedestrian dummies on some moving track.

Methods: An analysis of pedestrian crash trajectories, speeds, roadside features, and pedestrian behavior was used to create 18 unique crash scenarios representative of the most frequent and most costly crash types. For the study reported here, we only considered scenarios where the car is traveling straight because these represent the majority of fatalities. We manipulated driver expectation of a pedestrian both by presenting intersection and mid-block crossing as well as by using features in the scene to direct the driver's visual attention toward or away from the crossing pedestrian. Three visual environments for the scenarios were used to provide a variety of roadside environments and speed: a 20–30 mph residential area, a 55 mph rural undivided highway, and a 40 mph urban area.

Results: Many variables of crash situations were considered in selecting and developing the scenarios, including vehicle and pedestrian movements; roadway and roadside features; environmental conditions; and characteristics of the pedestrian, driver, and vehicle. The driving simulator scenarios were subjected to iterative testing to adjust time to arrival triggers for the pedestrian actions. This article discusses the rationale behind creating the simulator scenarios and some of the procedural considerations for conducting this type of research.

Conclusions: Crash analyses can be used to construct test scenarios for driver behavior evaluations using driving simulators. By considering trajectories, roadway, and environmental conditions of real-world crashes, representative virtual scenarios can serve as safe test beds for advanced driver assistance systems. The results of such research can be used to inform pedestrian crash avoidance/mitigation systems by identifying driver error, driver response time, and driver response choice (i.e., steering vs. braking).     

Exploring guerrilla gardening: gauging public views on the grassroots activity

The literature on guerrilla gardening is developing rapidly. The majority of these accounts currently derive from North America, with little academic exploration apparent beyond this context: they focus explicitly on the grass-roots gardeners and show little regard for those surrounding the action's location. Guerrilla gardeners often colonise land not only without the permission from authorities, but also with little regard for those who surround the space; transforming areas without consulting with the local communities. This paper explores those affected by guerrilla gardening; grounding our argument in evidence gathered from the activities of three guerrilla groups. In doing so, we investigate the public's views of several informal gardening projects, questioning their value and impact on the surrounding areas. The emerging responses are very mixed, ranging from positive comments about improving aesthetics, to negative remarks surrounding the practices of some groups. Ultimately, this paper demonstrates how, although often promoted and perceived to be a constructive activity, guerrilla gardening can result in adverse impacts on those who surround colonised sites.     

Operationalizing ecosystem service bundles for strategic sustainability planning: A participatory approach

The ecosystem service concept is recognized as a useful tool to support sustainability in decision-making. In this study, we collaborated with actors in the Helge å catchment, southern Sweden, in an iterative participatory ecosystem service assessment. Through workshops and interviews, we jointly decided which ecosystem services to assess and indicators to use in order to achieve a sense of ownership and a higher legitimacy of the assessment. Subsequently, we explored the landscape-level interactions between the 15 assessed services, and found that the area can be described using three distinct ecosystem service bundles. The iterative, participatory process strengthened our analysis and created a shared understanding and overview of the multifunctional landscape around Helge å among participants. Importantly, this allowed for the generated knowledge to impact local strategic sustainability planning. With this study, we illustrate how similar processes can support local decision-making for a more sustainable future.Electronic supplementary materialThe online version of this article (10.1007/s13280-020-01378-w) contains supplementary material, which is available to authorized users.