基于“哨兵-3A”OLCI影像的太湖蓝藻水华荧光基线高度指数信号特征分析

利用新型遥感数据"哨兵-3A"卫星OLCI影像数据,基于其665,681和708 nm波段构建的"荧光基线高度"指数算法,采用SNAP 6.0遥感专业软件,计算了2017年不同季节4个典型日期太湖FLH的全湖分布及蓝藻水华区信号强度特征。以完成了瑞利散射及气体吸收订正的3个波段的遥感反射率数据计算FLH图像,结果表明,FLH数值的"负偏"程度与蓝藻水华强度有很好的对应关系,FLH值"负偏"越大,蓝藻水华越严重,可以作为比较不同季节水华强度的有效遥感指标;富营养化较严重、较为浑浊、以蓝藻为优势种的内陆水体与大洋清洁、非蓝藻优势浮游植物水体的FLH"正偏"信号特征迥异。     

城市自然景区游客环境责任行为影响因素研究

城市自然景区是城市中不可多得的旅游资源和游憩空间,游客旅游行为对城市自然景区的游憩冲击一直是城市旅游管理亟待解决的棘手问题,研究游客的环境责任行为是控制游憩负面冲击,增强城市自然景区可持续发展能力的有效途径。本研究在国内外文献综述和实践观察基础上,将游客社会责任意识引入游客环境冲击感知和环境责任行为的关系研究中,建立了包含生态环境冲击感知、不友善行为感知、游客冲突感知和设施管理冲击感知四个游憩冲击感知变量,自我约束行为和保护促进行为两个环境责任行为变量的"游憩冲击感知—社会责任意识—环境责任行为"理论模型,应用问卷调查和结构方程模型,以长沙岳麓山国家5A级景区为案例,对城市自然景区游客环境责任行为的影响因素及其相互关系展开定量实证研究。研究发现:(1)游客游憩冲击感知对环境责任行为的直接影响作用较小,生态环境冲击感知对环境保护促进行为具有显著正向影响;(2)游客社会责任意识对环境自我约束行为具有显著正向影响,其在游客环境冲击感知、设施管理冲击感知、游客冲突感知与环境责任行为的影响关系中起中介作用;(3)游客冲击感知对社会责任意识的影响主要表现为游客生态环境冲击感知和设施管理冲击感知对游客社会责任意识具有显著的正向影响,而游客冲突感知对游客社会责任意识具有显著的负向影响。根据研究结论,文章最后指出城市自然景区游客环境责任行为若干管理启示。     

Involvement of mitochondrial dysfunction in nanosized lead oxide induced cellular damage in human lung alveolar epithelial cells

High levels of industrial lead (Pb) exposure have decreased in the last 10 years as an outcome of removal of the metal from gasoline and paints. However, environmental Pb exposures remain extensive and may be correlated with adverse human health outcomes. The present study was designed to examine molecular mechanisms underlying cytotoxicity of lead oxide nanoparticles (PbONPs) on human lung alveolar epithelial (A549) cells. When A549 cells were incubated with PbONPs, the production of reactive oxygen species was enhanced as observed by 2',7'-dichlorodihydrofluorescein diacetate. PbONPs significantly reduced proliferation of A549 cells and increased caspase3 activity. In addition, exposure of PbONPs decreased levels of glutathione, and increased lipid peroxide levels and activities of superoxide dismutase and catalase. Exposure of PbONPs enhanced DNA damage as evidenced by tail DNA (%) and olive tail moment. Taken together, these finding indicated that PbONPs diminished cell proliferation and increased apoptotic cell death of A549 cells.     

Artisanal and small-scale gold mining in Burkina Faso: Suggestion of multi-agent methodology as a complementary support in elaborating a policy

In order to better manage artisanal and small-scale gold mining, the Burkinabe authorities have planned to build a suitable methodological support as an aid to elaborating appropriate policies and actions. The developed methodology concerns (a) at a spatial level, the generation and analysis of a geological resources map needed by the artisanal miners and (b) at a socioeconomic level, analysis of the miners' activity. This paper reports and discusses the results of our suggestion to also introduce the use of an approach known as multi-agent system (MAS) as a complementary part of this initial methodology, at a downstage level to the above two analysis stages. MAS methodology could be used to develop simulation models to forecast the future of the activity. MAS is appropriate for describing the dynamics of systems where it is impossible to obtain all output data of a model from a purely mathematical or statistical transformation of input data. Our suggestion involves (i) demonstrating the capacity of the approach to simulate all parameters needed by mining policy makers and (ii) evaluating to what extent the methodology is accepted by them, as well as, at a more scientific level, the literature regarding mining system simulation.     

Field dissipation of 4-nonylphenol, 4-t-octylphenol, triclosan and bisphenol A following land application of biosolids

The persistence of contaminants entering the environment through land application of biosolids needs to be understood to assess the potential risks associated. This study used two biosolids treatments to examine the dissipation of four organic compounds: 4-nonylphenol, 4-t-octylphenol, bisphenol A and triclosan, under field conditions in South Australia. The pattern of dissipation was assessed to determine if a first-order or a biphasic model better described the data. The field dissipation data was compared to previously obtained laboratory degradation data. The concentrations of 4-nonylphenol, 4-t-octylphenol and bisphenol A decreased during the field study, whereas the concentration of triclosan showed no marked decrease. The time taken for 50% of the initial concentration of the compounds in the two biosolids to dissipate (DT50), based on a first-order model, was 257 and 248 d for 4-nonylphenol, 231 and 75 d for 4-t-octylphenol and 289 and 43 d for bisphenol A. These field DT50 values were 10- to 20-times longer for 4-nonylphenol and 4-t-octylphenol and 2.5-times longer for bisphenol A than DT50 values determined in the laboratory. A DT50 value could not be determined for triclosan as this compound showed no marked decrease in concentration. The biphasic model provided a significantly improved fit to the 4-t-octylphenol data in both biosolids treatments, however, for 4-nonylphenol and bisphenol A it only improved the fit for one treatment. This study shows that the use of laboratory experiments to predict field persistence of compounds in biosolids amended soils may greatly overestimate degradation rates and inaccurately predict patterns of dissipation.     

Simultaneous determination of organochlorine pesticides and bisphenol A in edible marine biota by GC-MS

A study to assess the level of organochlorine pesticides (OCPs) and bisphenol A (BPA) in edible marine biota collected from coastal waters of Malaysia was conducted using GC-MS and SPE extraction. An analytical method was developed and validated to measure the level of 15 OCPs and BPA simultaneously from five selected marine species. It was observed that some samples had low levels of p,p′-DDE, p,p′-DDT and p,p′- DDD ranging from 0.50 ng g⁻¹ to 22.49 ng g⁻¹ dry weight (d.w) but significantly elevated level of endosulfan I was detected in a stingray sample at 2880 ng g⁻¹ d.w. BPA was detected in 31 out of 57 samples with concentration ranging from below quantification level (LOQ: 3 ng g⁻¹) to 729 ng g⁻¹ d.w. The presence of OCPs is most likely from past use although there is also indication of illegal use in recent times. The study also reveals that BPA is more widely distributed in coastal species caught off the coast of the most developed state. The potential health risk from dietary intakes of OCPs and BPA from the analysed fish species was negligible.     

Induction to oxidative stress by saxitoxin investigated through lipid peroxidation in Neuro 2A cells and Chlamydomonas reinhardtii alga

Saxitoxin (STX) is a cyanotoxin, which can cause neurotoxic effects and induce ecological changes in aquatic environments, a potential risk to public and environmental health. Many studies of cytotoxicity on animal cells and algae have been performed, although few compare the toxic effects between the two models. In this sense, we investigated the oxidative stress induced by STX (0.4-3.0 nM) in two different cellular models: Neuro-2A (N2A) cells and Chlamydomonas reinhardtii alga by quantification of malondialdehyde (MDA) levels as indicative of lipid peroxidation (LPO). Also was evaluated the antioxidant defense of these cells systems after exposure to STX by the addition of antioxidants in N2A cells culture, and by the measure of antioxidants enzymes activity in C. reinhardtii cells. The MDA levels of N2A cells increased from 15% to 113% for 0.4 and 3.0 nM of STX, respectively, as compared to control. Superoxide-dismutase and catalase did not appear to protect the cell from STX effect while, in cells treated with vitamin E, the rates of MDA production decreased significantly, except for higher concentrations of STX. No MDA productions were observed in algal cells however some effects on antioxidant enzymes activity were observed when algae were exposed to 3.0 nM STX. Our results indicate that the concentrations of STX that may induce oxidative stress through LPO are different in animal and phytoplankton communities. A combination of algal and animal bioassays should be conducted for reliable assessment of oxidative stress induced by STX.     

智能楼宇的指纹门禁系统

介绍一套基于TMS320VC5509A的指纹识别系统的硬件设计方案,并重点对指纹采集模块、指纹处理模块、CPLD接口模块进行了详细讨论.     

A~2/O工艺重新启动试验的污泥活性恢复研究

以处理实际城市污水的小试规模A2/O工艺为研究对象,在处理工艺稳定运行的基础上关停装置60 d,进行了"饥饿"期内不同关停模式下系统重新启动后污泥活性恢复的研究.结果表明,循环模式、厌氧模式和微曝模式3种不同关停模式下,系统重启第4天,污泥硝化性能及反硝化性能基本恢复甚至超过关停前水平,而脱碳性能和除磷性能的恢复速度则较缓慢,重新启动后系统呈现较好的反硝化除磷能力;重启第12天后3种关停模式出水水质良好,基本满足<城镇污水处理厂污染物排放标准>(GB 18918-2002)一级B标准.不同关停模式下,系统污泥活性恢复速率及出水水质对比显示,污水处理厂故障检修期间将搅拌、曝气等动力设备完全关闭的厌氧模式下系统污泥活性恢复较快,而且能耗最低.     

厌氧—交替O/A的序批式膜生物反应器脱氮除磷性能比较

提出一种高效脱氮除磷的新工艺,即厌氧-交替O/A的序批式膜生物反应器.在HRT为8.4 h、交替O/A时间为10min/10 min时,系统氨氮、总氮、总磷的平均去除率分别达到99.57%、89.92%、93.26%.典型周期试验证明.频繁的O/A环境更利于系统高效脱氮除磷,且O/A交替越频繁,系统中反硝化聚磷菌(DPAO)占聚磷菌(PAO)的比例(即缺氧吸磷速率与好氧吸磷速率的比值)越大.当交替O/A时间为10 min/10 min时.系统中DPAO占PAO的比例为70.87%,比交替O/A时间为30 min/30 min时提高了66%.