Contaminant Exposure of Barn Swallows Nesting on Bayou D'Inde, Calcasieu Estuary, Louisiana, USA

Current and historical point source discharges, storm water runoff, and accidental spills have contaminated the water, sediment, and biota within the Calcasieu Estuary in southwestern Louisiana. In 2003, barn swallow (Hirundo rustica) eggs and nestlings were collected beneath two bridges that cross Bayou d′Inde, the most contaminated waterway within the Calcasieu Estuary. Samples were also collected from a bridge over Bayou Teche, a reference site in south central Louisiana. Polychlorinated biphenyl (PCB) concentrations in barn swallow eggs and nestlings were significantly higher at the downstream site on Bayou d′Inde (2.8 μ g/g PCBs in eggs and 1.5 μ g/g PCBs in nestlings) than at the other two sites (< 0.2 μ g/g PCBs in eggs and nestlings at both sites). Ethoxyresorufin-O-dealkylase activity in nestling livers was significantly higher at the downstream site on Bayou d′Inde (50 pmol/min/mg) compared to the other two locations (24 pmol/min/mg, each), probably because of exposure to PCBs. Polychlorinated dibenzo-p-dioxin and polychlorinated dibenzofuran concentrations in eggs and polycyclic aromatic hydrocarbons in nestlings were at background concentrations at all sites. Trace element concentrations in barn swallow eggs and nestling livers were at background levels and did not differ among the three sites. A biomarker of DNA damage did not differ among sites.     

氯吡嘧磺隆和镉复合对斑马鱼肝脏的影响

为了探究污染物镉和氯吡嘧磺隆复合污染对非靶标生物斑马鱼的毒性作用,通过急性毒性试验,获得镉和氯吡嘧磺隆对斑马鱼的LC50.以LC25作为0水平,设置9个处理组进行试验,检测不同处理组斑马鱼96 h死亡率、斑马鱼肝脏中CAT、MDA和羧酸酯酶CarE.检测结果表明,镉和氯吡嘧磺隆对斑马鱼存在交互作用,当水体中镉浓度为3....     

解读摄影的本体语言

摄影本体语言是其传递视觉信息的方式,融入照相机、镜头以及成像系统最前沿的科学技术。摄影本体语言包含摄影的纪实性、瞬间性、时间与空间的拓展、镜头透视关系变化、清晰与模糊的运用等。这些视觉语言是最具摄影性质的语言,也是摄影区分其他平面艺术的要素和本质。而构图、用光、影调和色彩的表现是摄影与绘画相互交融的造型语言,是摄影视觉表达的技术与技巧。摄影本体语言和造型语言相互交融,创造影像视觉表达与表现的价值。     

硫酸锰渣污染土壤中重金属的形态分布及生物活性

测定了硫酸锰渣污染土壤中Cu,Zn,Cd,Pb,Mn的总量和各形态含量.结果表明重金属总量远超过环境背景值和土壤环境二级标准.重金属各形态分布特征:Cu,有机态>残渣态>铁锰氧化态>碳酸盐态>可交换态;Zn,残渣态>铁锰氧化态>有机态>碳酸盐态>可交换态;Cd,铁锰氧化态>可交换态>碳酸盐态>残渣态>有机态;Pb,铁锰氧化态>残渣态>有机态>碳酸盐态>可交换态;Mn,铁锰氧化态>残渣态>可交换态>有机态>碳酸盐态.重金属的生物可利用性系数和迁移系数均为Cd>Mn>Pb>Cu>Zn.     

Endosulfan induces changes in spontaneous swimming activity and acetylcholinesterase activity of Jenynsia multidentata (Anablepidae, Cyprinodontiformes)

We assessed changes in spontaneous swimming activity and acetylcholinesterase (AchE) activity of Jenynsia multidentata exposed to Endosulfan (EDS). Females of J. multidentata were exposed to 0.072 and 1.4 μg L⁻¹ EDS. Average speed and movement percentage were recorded during 48 h. We also exposed females to EDS at five concentrations between 0.072 and 1.4 μg L⁻¹ during 24 h, and measured the AchE activity in brain and muscle. At 0.072 μg L⁻¹ EDS swimming motility decreased relative to the control group after 45 h, while at 1.4 μg L⁻¹ EDS swimming motility decreased after 24 h. AchE activity significantly decreased in muscle when J. multidentata were exposed to EDS above 0.072 μg L⁻¹, while no significant changes were observed in brain. Thus, changes in swimming activity and AchE activity in muscle are good biomarkers of exposure to EDS in J. multidentata.     

生物处理镉污染土壤及其酶活性研究

以添加镉的天津农田土壤为对象,分别设定空白处理、添加诺沃肥处理及生物强化处理(添加1株紫外线诱变工程菌和诺沃肥).研究土壤在不同pH、温度和含水率条件下可提取有效态镉(E-Cd)、过氧化氢酶及脲酶活性的变化情况.结果表明,添加诺沃肥处理可以有效降低E-Cd含量.而生物强化处理可进一步促进镉的固定效果;最适合生物修复的环境条件为PH 7.0、温度30℃和土壤含水率50%;添加诺沃肥处理和生物强化处理的土壤中过氧化氢酶和脲酶活性明显高于空白处理,说明生物修复后,土壤酶活性已经恢复,表明这2种处理能改善土壤结构和性能,提高土壤的肥力.     

微生物絮凝剂产生菌的筛选及其絮凝特性

采用常规的微生物学方法,从垃圾渗滤液中筛选到一株高效微生物絮凝剂产生菌LB1,根据其形态学和生理生化特征初步鉴定该菌株属于假单胞菌属,命名为Pseudonomas sp. LB1。LB1所产微生物絮凝剂的絮凝特性的研究结果表明,LB1的最佳产絮凝时间为96 h,所产絮凝活性物质主要是其生长过程中的胞外分泌物和细胞生长后期的次级代谢产物,菌体细胞本身具有一定的助凝作用。LB1所产絮凝剂最佳加样量为3％（体积分数V/V）;对pH的适应范围较宽,在4～10之间具有较高的絮凝活性,均大于75％;温度为25℃时絮凝率为86.3％,在25～60℃之间,絮凝率基本保持稳定;LB1所产絮凝剂对几种废水具有较好的絮凝效果。     

Increasing stair climbing in a train station: The effects of contextual variables and visibility

Accumulation of physical activity during daily living is a current public health target that is influenced by the layout of the built environment. This study reports how the layout of the environment may influence responsiveness to an intervention. Pedestrian choices between stairs and the adjacent escalators were monitored for 7 weeks in a train station (Birmingham, UK). After a 3.5 week baseline period, a stair riser banner intervention to increase stair climbing was installed on two staircases adjacent to escalators and monitoring continued for a further 3.5 weeks. Logistic regression analyses revealed that the visibility of the intervention, defined as the area of visibility in the horizontal plane opposite to the direction of travel (termed the isovist) had a major effect on success of the intervention. Only the largest isovist produced an increase in stair climbing. Additionally, stair climbing was more common during the morning rush hour and at higher levels of pedestrian traffic volume. The layout of the intervention site can influence responsiveness to point-of-choice interventions. Changes to the design of train stations may maximize the choice of the stairs at the expense of the escalator by pedestrians leaving the station.     

Analysis of Coupling between Soil and Water Conservation and Economic-social Development

The coupling relation exists in water and soil conservation and economic-social development. The article analyses the relation of soil and water conservation and economic-social development stages as well as the coupling analytical method. Then calculates the expecting income by dispersing Markov decision and calculates the correlation coefficient and the relationship degree. The article obtains the relationship of soil and water conservation investments and all kinds of incomes. Finally, it analyzes the important meaning in socio-economic development of water and soil conservation.     

Change of Flood Patterns in China under the Influences of Climate Change and Human Activities

Based on the flood affected area （FA） data of the provinces in China from 1950 to 2005, the article discusses the change of the flood patterns in China, and investigates its relationship with climate change and human activities. The flood center shifted from North China and the Yangtze-Huaihe basin in the 1950s towards the south, north and west of China, and located in the south of the Yangtze River and South China after the 1990s. The FA in the western provinces was continuously on the rise since the 1950s. There are two characteristics for the future flood pattem in China. The pattern of ＂flood in the south and drought in the north＂ depends on the north-south shift of the maximum rainfall region in eastern China. The flood intensification to the west of Hu Huanyong＇s line mainly results from the increase of rainfall, extreme precipitation and the melting of glaciers under the background of human activity magnification.