Using a social learning configuration to increase Vietnamese smallholder farmers’ adaptive capacity to respond to climate change

Social learning is crucial for local smallholder farmers in developing countries to improve their adaptive capacity and to adapt to the current and projected impacts of climate change. While it is widely acknowledged that social learning is a necessary condition for adaptation, few studies have systematically investigated under which conditions particular forms of social learning are most successful in improving adaptive capacity of the most vulnerable groups. This study aims to design, implement and evaluate a social learning configuration in a coastal community in Vietnam. We make use of various methods during four workshop-based interventions with local smallholder farmers: interviews with key farmers and commune leaders, farmer-to-farmer learning, participatory observations and focus group discussions. The methods for evaluation of social learning configuration include in-depth interviews, focus group discussions and structured survey interviews. Our findings show that the social learning configuration used in this study leads to an increased problem ownership, an enhanced knowledge-base with regard to climate change impacts and production adaptation options, improved ability to see connections and interdependencies and finally, strengthened relationships and social cohesion. The results suggest that increased social learning in the community leads to increase in adaptive capacity of smallholder farmers and improves both their economic and environmental sustainability. We discuss the key lessons for designing learning configurations that can successfully enhance adaptive capacity and smallholder farmers’ agency and responsiveness to the challenges posed by climate change impacts.     

基于机器学习利用低成本传感器数据构建城市近地面PM2.5浓度的高分辨率空间分布

PM_2.5是当前影响中国城市空气质量的一种重要污染物,它对人体健康有不利影响,高时空间分辨率的PM_2.5浓度分布是城市大气污染 精细化防控和健康影响评估的重要基础.低成本传感器在中国城市空气质量监测领域得到越来越多的应用,但由于其数据质量不够高,其价值没有得到充分的挖掘.本研究以在长三角地区蚌埠市城区作为研究案例,首先基于国控站监测数据对低成本传感器观测数据进行校准.接着通过6种机器学习模型的预测性能的比较选取随机森林作为本研究的核心方法.然后利用随机森林方法结合土地利用类型、人口密度和通过WRF模式模拟得到的气象数据、监测数据等多源数据,构建了时间分辨率为1 h、空间分辨率为0.005°（接近500 m）的近地面PM_2.5浓度的时空分布.最后对几种方法的结果进行了比较和评估.反演得到的高分辨率PM_2.5浓度的10倍交叉验证结果显示,空间R²=0.95,RMSE=9.32 μg·m^-3,时间R²=0.88,RMSE=9.24 μg·m^-3.结果表明,低成本传感器观测数据可以帮助人们构建具有更高精度的高时空分辨率的PM_2.5浓度 分布,使得低成本传感器数据的时空特征价值得到更好的利用,同时也可为低成本传感器更好地服务于空气质量精细化管理提供一种新的 应用思路.     

贵州省薏苡秸秆处置现状调查分析—以兴仁市为例

贵州省兴仁市是中国最大的薏苡产地,且薏苡是重要杂粮作物,目前薏苡秸秆处置资源化利用程度低.为提高秸秆资源化利用率,对薏苡秸秆组成成分分析,调查秸秆资源化利用现状,分析资源化利用难点并提出建议.结果显示:薏苡秸秆成分中,主要有纤维素(37.47％),半纤维素(22.70％),木质素(13.44％),粗蛋白(8.08％),...     

新加坡环境风险管控对我国城市规划的启示

新加坡作为世界上人口密度最高的国家之一,有限的土地上承载了多个大型石化企业,不仅拥有世界第三大炼油中心和重要的石化中心,还被誉为"花园城市",这与其在重工业发展过程中重视环境风险管控密不可分。概述了新加坡先进的环境风险管控理念,分析了我国在环境风险管控方面存在的突出问题,即在规划源头缺乏环境管制、不同用地类型环境功能不相容、各地化工园区泛滥且产业布局混乱;指出新加坡从规划源头控制环境风险的先进理念对我国土地利用规划和环境风险管控具有一定的启示作用,并建议我国在规划源头增加明确的环境风险管控要求,根据环境风险实施土地使用类型的梯级过渡,规定强制隔离要求,针对现有城市建设和规划开展环境安全评估,全面推进化学品项目及园区的管理、清理和整顿。     

Fenton试剂与骨架构建体复合调理剂对污泥脱水性能的影响

将Fenton试剂与骨架构建体联用作为复合调理剂开展了污泥调理及脱水试验.结果表明,赤泥与水泥作骨架构建体调理后,污泥脱水性能和脱水液pH均优于石灰与水泥调理污泥.以污泥比阻(SRF)为评价指标,开展了Fenton反应时间、初始pH及调理剂投加量对污泥脱水性能影响的单因素试验.当Fenton反应时间为90 min,初始pH为5,水泥、赤泥、Fe²⁺和H₂O₂的投加量(以污泥干固体质量计)分别为300、300、40和32 mg·g^-1时,污泥比阻降低率可达94.25%±0.21%.在此基础上,以泥饼含水率为响应指标,利用表面响应法对调理剂投加量进行优化.结果表明,水泥、赤泥、Fe²⁺和H₂O₂的投加量分别为287、287、46和37 mg·g^-1,泥饼含水率可降至47.7%±0.8%.调理后污泥的粒径减小,比表面积增大,粘度减小,Zeta电位由负变正,说明该复合调理剂能有效地破解胞外聚合物(EPS),提高污泥脱水性能.     

Past climate, future perspective: an exploratory analysis using climate proxies and drought risk assessment to inform water resources management and policy in Maine, USA

In recent decades, significant progress has been made toward reconstructing the past climate record based on environmental proxies, such as tree rings and ice core records. However, limited examples of research that utilizes such data for water resources decision-making and policy exist. Here, we use the reconstructed record of Palmer Drought Severity Index (PDSI), dating back to 1138AD to understand the nature of drought occurrence (severity and duration) in the state of Maine. This work is motivated by the need to augment the scientific basis to support the water resources management and the emerging water allocation framework in Maine (Maine Department of Environmental Protection, Chapter 587). Through a joint analysis of the reconstructed PDSI and historical streamflow record for twelve streams in the state of Maine, we find that: (a) the uncertainties around the current definition of natural drought in the Chapter 587 (based on the 20th century instrumental record) can be better understood within the context of the nature and severity of past droughts in this region, and (b) a drought index provides limited information regarding at-site hydrologic variations. To fill this knowledge gap, a drought index-based risk assessment methodology for streams across the state is developed. Based on these results, the opportunities for learning and challenges facing water policies in a changing hydroclimate are discussed.     

太子河洛氏鱥幼鱼栖息地适宜度评估

基于对太子河流域鱼类及栖息地的调查研究,选择该流域的优势种洛氏鱥(Phoxinus lagowskii)作为指示生物,建立洛氏鱥幼鱼对水深、流速、溶解氧、总溶解颗粒物和河岸带植被指数的栖息地适宜度曲线,并借鉴河道内流量增量法计算各采样点河段的洛氏鱥幼鱼栖息地适宜度指数。结果表明:洛氏鱥幼鱼栖息地适宜度指数在太子河上游较高(>0.5),中游次之(0.2-0.5),下游较低(<0.2)。洛氏鱥幼鱼栖息地适宜度指数与10项栖息地调查指标和土地利用类型的相关性分析表明:太子河流域内限制洛氏鱥幼鱼生存的因素不是水文条件,而是河流水质及河岸带等环境因素;洛氏鱥幼鱼栖息地适宜度指数受人类活动影响较大,随着太子河中下游人类开发强度加大,洛氏鱥栖息地质量呈下降趋势。     

郑州市大气PM2.5中水溶性离子的污染特征及来源解析

为探究郑州大气细颗粒物PM_2.5中水溶性无机离子(WSIIs)的污染特征、季节变化和来源,有针对性地防治PM_2.5的污染,2020年12月至2021年10月4个不同季节连续采集PM_2.5样品,并结合气态污染物(SO₂、 NO₂和O₃)和气象因素(温度和相对湿度)对9种WSIIs(NO^-₃、 NH⁺₄、 SO₄^2-、 Ca²⁺、 K⁺、 Na⁺、 Mg²⁺、 F^-和Cl^-)进行分析.结果表明,观测期ρ[总水溶性离子(TWSIIs)]年均值为(39.34±21.56)μg·m^-3,呈现出冬季最高、夏季最低的季节变化特征.全年PM_2.5均稍微偏碱性,NH     

Synthesis and characterisation of transition metal sulphide-loaded fly ash–based mesoporous EU-12 photocatalysts for degradation of rhodamine B

Transition metal sulphide-loaded fly ash–based EU-12 photocatalysts were synthesized by sono-hydrothermal method followed by ion exchange. The composites were characterized by XRD, FESEM, DSC-TGA, Raman spectroscopy, and BET surface area analysis. The XRD results imply 76.39% crystallinity of EU-12 and morphological studies by FESEM, and TEM revealed the shape and size of EU-12, i.e. rod-shaped with size ranging from 5 to 200 nm. Band gap of all synthesized photocatalysts were found to be?≤?3.44 eV. The photoactivities of the photocatalysts were examined by degrading rhodamine B (RhB). The results indicated that metal sulphide/EU-12 composite had the strong photoactivity under visible light compared to dark environment. Furthermore, the efficiency of photocatalysts was determined in terms of degradation efficiency towards RhB which was found to be maximum of 98.62% for 0.2 M CdS/EU-12 at 2 gL^?1 of catalyst dosage and 10 ppm of dye concentration within 3 h under visible light source of 200 W.