高原富营养化湖泊杞麓湖微囊藻毒素分布特征、相关因子及其健康风险分析     

王永强  国晓春  卢少勇  宋迪  蒋昀耕  杨莉园 《湖泊科学》2024,36(1):52-63

杞麓湖作为典型的富营养化高原湖泊,其藻华暴发引发的微囊藻毒素(microcystins, MCs)污染问题会危害水生态安全并造成人体健康风险。为了评估杞麓湖流域MCs的秋冬季节污染现状以及健康风险情况,对湖内和7条主要入湖河流入湖口的表层水进行采样检测,分析MCs主要异构体的时空分布特征,研究MCs与水质和浮游植物等环境因子的关系,并通过人体非致癌健康风险评价MCs的风险等级。结果发现,MCs浓度自秋季到冬季呈下降趋势,秋季湖内胞内MCs(IMCs)占比超过99%,冬季IMCs与胞外MCs(EMCs)浓度接近。MC-RR和MC-LR是主要的MCs异构体类型,其中MC-RR在秋季浓度占比高于MC-LR和MC-YR,而冬季MC-LR最高。MCs与微囊藻密度等生物因子呈极显著正相关关系,与TN、TP和NH₃-N营养盐呈显著负相关关系。杞麓湖EMCs污染的风险指数范围为0.004~0.110,处于极低或低风险,冬季风险略高于秋季,因南岸入湖EMCs污染以及湖内IMCs释放带来的风险需要进一步关注。  相似文献   

无定河流域不同水土流失区底栖动物生物完整性指数构建与健康评价     

侯湘然  潘保柱  侯易明  胡恩  贺瑶  冯治远 《湖泊科学》2024,36(1):274-285

无定河流域位于黄土高原与毛乌素沙地过渡带,水土流失严重,生态环境具有脆弱性和波动性。于2021年春季(4月)和秋季(10月)对无定河流域上、中、下游及其6条支流和流域内的3个淤地坝开展水生态系统调查,旨在厘清无定河流域底栖动物群落特征,构建底栖动物生物完整性指数并开展健康评价。无定河流域春季共采集到底栖动物105种,平均密度为181 ind./m²,平均生物量为0.760 g/m²,秋季共采集到底栖动物67种,平均密度为94 ind./m²,平均生物量为0.454 g/m²。通过对两季度研究区域内底栖动物27个生物参数开展分布范围检验、判别能力分析和相关性分析,构建无定河流域底栖动物生物完整性指数,对全流域40个样点(6个参照点和34个受损点)进行B-IBI健康评价。评价结果表明,总体上无定河流域底栖动物生物完整性较好,40个样点中春季有19个处于健康或亚健康状态,秋季有23个处于健康或亚健康状态,其中无定河上、中游干支流大都以健康和亚健康为主,无定河下游干支流以及3个淤地坝水体健康状况较差。在不同水土流失类型区域,底栖动物群落特征和生物完整性评价具有显著性差异。本研究结果可为无定河流域河流健康评估提供科学依据。  相似文献   

遥感在森林精准培育中的应用现状与展望   总被引：1，自引：0，他引：1  

周凯  曹林 《遥感学报》2021,25(1):423-438

随着社会经济快速发展及人口增长,中国木材供需矛盾突出,对外依存度高。面对有限的土地资源,迫切需要更为高效、高质量地培育森林资源,在定向培育和集约经营等的各个环节实现培育技术精准化。现代遥感技术所构建的多平台、多角度、多模式立体观测体系及定量分析方法是森林精准培育的关键技术。以遥感技术为核心所构建的从土壤类型分析、土地适应性评价、生态环境模拟到林木育种、灌溉施肥、林木长势监测、病虫害防治等一体化、精准化的森林精准培育新体系,将全面支撑现代林业的整体提质增效和森林质量精准提升。本文首先介绍了RGB相机、多光谱、高光谱、激光雷达、热红外和荧光传感器在森林精准培育中应用现状,并对其应用特点及测量指标进行了综合比较;然后,重点介绍了遥感在林木良种选育、营养胁迫监测诊断及水肥精准喷灌以及森林病虫害防治与健康评估这3个森林精准培育重要方向上的应用,并分析了各应用方向的共性需求;最后,从3个方面,即多源遥感信息融合,人工智能、物联网及3S技术集成,以及遥感数据与生理生态模型和辐射传输模型等的集成应用,分析了未来遥感技术在森林精准培育中的发展趋势及应用前景。  相似文献   

Ethical challenges to medical assistance at sea     

《Marine Policy》2017

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Effects of rainfall,geomorphological and geometrical variables on vulnerability of the lower Mississippi River levee system to slump slides     

Farshid Vahedifard  Sona Sehat  James V. Aanstoos 《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2017,11(3):257-271

This study investigated the importance of rainfall and various geomorphological and geometrical factors to the vulnerability of earthen levees to slump slides. The study was performed using a database including 34 slump slides that occurred in the lower Mississippi River levee system from 2008 to 2009. The impact of rainfall within the six months prior to slide occurrence was studied for 23 slides for which an accurate occurrence date was available. Several variables were used to develop a logistic regression model to predict the probability of slump slide occurrence. The proposed model was verified for both slide and non-slide cases. The regression analysis depicts the impact of channel width, river sinuosity index, riverbank erosion, channel shape condition and distance to river. Excluding the sinuosity index, the impact of the other independent variables examined was found to be significant. Occurrence of riverbank erosion around the slide locations was the most significant predictor factor. A channel width of less than 1000?m was ranked as the second most significant variable. The proposed model can aid in locating high-risk areas on levees in order to take prompt protective measures, increase monitoring efforts and enable early response under emergency conditions.  相似文献   

1D System identification of a 54‐story steel frame building by seismic interferometry          下载免费PDF全文

Mohammadtaghi Rahmani  Maria I. Todorovska 《地震工程与结构动力学》2014,43(4):627-640

A 54‐story steel, perimeter‐frame building in downtown Los Angeles, California, is identified by a wave method using records of the Northridge earthquake of 1994 (M_L = 6.4, R = 32 km). The building is represented as a layered shear beam and a torsional shaft, characterized by the corresponding velocities of vertically propagating waves through the structure. The previously introduced waveform inversion algorithm is applied, which fits in the least squares sense pulses in low‐pass filtered impulse response functions computed at different stories. This paper demonstrates that layered shear beam and torsional shaft models are valid for this building, within bands that include the first five modes of vibration for each of the North–South (NS), East–West (EW), and torsional responses (0–1.7 Hz for NS and EW, and 0–3.5 Hz for the torsional response). The observed pulse travel time from ground floor to penthouse level is τ ≈1.5 s for NS and EW and τ ≈ 0.9 s for the torsional responses. The identified equivalent uniform shear beam wave velocities are β_eq ≈ 140 m/s for NS and EW responses, and 260 m/s for torsion, and the apparent Q ≈ 25 for the NS and torsional, and ≈14 for the EW response. Across the layers, the wave velocity varied 90–170 m/s for the NS, 80–180 m/s for the EW, and 170–350 m/s for the torsional responses. The identification method is intended for use in structural health monitoring. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Detection thresholds in structural health monitoring     

《Soil Dynamics and Earthquake Engineering》2014

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IPCC第五次评估报告气候变化对人类福祉影响的新认知   总被引：2，自引：0，他引：2  

张存杰  黄大鹏  刘昌义  刘起勇 《气候变化研究进展》2014,10(4):246-250

IPCC第五次评估报告（AR5）第二工作组（WGII）报告评估了气候变化对人类健康、人类安全、生计与贫困的影响,指出气候变化已经对人类健康和安全造成了负面影响,气候变化、气候变率和极端气候事件给城市和农村的贫困人口增添了额外的负担,与气候变化相关的风险增大。21世纪的气候变化,将继续加剧现有健康问题,增加人类的迁徙,放大冲突的驱动因素的影响,对许多国家的关键基础设施造成不利影响,给小岛国和有很长海岸线国家的领土完整带来风险;整个21世纪,气候变化将减缓经济增长,进一步威胁粮食安全,使减贫更为困难,贫困问题更加突出。  相似文献   

Bacterial Proliferation in Municipal Water Supplied in Mirpur Locality of Dhaka City,Bangladesh          下载免费PDF全文

Mrityunjoy Acharjee  Farjana Rahman  Fahmida Jahan  Rashed Noor 《洁净——土壤、空气、水》2014,42(4):434-441

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The Concept and Development of Smart Structures Technologies for Long-span Cable-supported Bridges     

《Marine Georesources & Geotechnology》2013,31(3-4):315-331

This article presents an overview of smart structures technologies in connection with long-span cable-supported bridges. Considering the broad scope of the smart structures technologies, two subareas, namely, structural health monitoring and structural control technologies, and their applications in long-span cable supported bridges, are identified as the focus of this review. It is believed that by, adopting the smart structures technologies, reliable operation and hazard management of long-span bridges can be achieved much more efficiently and can be made economically feasible, especially for bridges located at sites with high risks of severe natural hazardous events, such as those facing the bridges of the Taiwan Strait Crossing project. The feasibility of and practical issues in implementing the smart structures technologies in the design and construction of long-span cable-supported bridges are also discussed here. Considering the time span of the construction of the Taiwan Strait Crossing, some of the innovative technologies with a high potential for future long-span bridge applications, while still at the stage of exploratory research at the time of writing, are also examined as it is believed these technologies might have become prevalent by the completion time of the Taiwan Strait Crossing project.  相似文献