State of the population of the European pearl mussel <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> (L.) (Mollusca,Margaritiferidae) at the northeastern boundary of its range (Solza River,White Sea Basin)

Only two river basins in which the European pearl mussel has survived to date are known in Arkhangelsk oblast. These are the Solza and Kozha basins. The northeastern boundary of the European range of this species passes along the watershed between the basins of the Solza and the Shirshema (the Onega Peninsula) and then along the Onega-Northern Dvina watershed. The population density and the proportion of juveniles widely vary in different parts of the Solza Basin, and, therefore, the previously conclusion concerning the ageing of the population in the Kazanka River (Bolotov and Semushin, 2003) applies only to certain parts of this river. The highest density of the pearl mussel in the Solza Basin is 68 ind./m². Fish cultivation contributes to the conservation of this pearl mussel population, as the release of Atlantic salmon juveniles ensures reproduction of the mollusk under conditions of regulated river flow.     

环境变化对鸟类种群结构的影响研究

文章将镇江市域内主要优势种树麻雀作为指示种,通过对种群数量、时空分布、不同生境分布、栖息地和森林植被等方面对树麻雀的生态影响进行了调查研究。结果表明：各生境中,分布密度以乡村与城镇最高,农田次之,森林、灌丛及水域最低;植被变化、城乡建设、以及农药、化肥的施用是引起某些鸟类数量变化的重要原因;以鸟类为代表的野生动物与环境关系密切,其分布区域和种群数量的变化以及群落参数变化反映和预示了环境的变化趋势。     

基于DEA的陕西省环境治理效率分析研究

借助于数据包络分析方法（DEA）对陕西省2002年-2009年的环境治理效率进行分析。分析结果表明,这8年陕西省环境治理技术效率的均值为0．985,其在规模效率上处于规模有效阶段的占75％,在技术效率上处于有效状态的占75％。这说明陕西省环境治理效率保持在一个较好的水平,但陕西省环境治理投入还没有充分地发挥作用,人才队伍建设水平有待提高,环境治理对经济发展和社会进步的贡献偏低。陕西省政府可采取一些措施使陕西环境治理效率进一步提高。     

威远江自然保护区思茅松种群的林窗更新研究

在野外考察的基础上,运用径级结构、高度结构的方法对思茅松种群的林窗更新进行研究,研究结果表明：思茅松纯林的林窗更新与灌草层盖度,尤其是草本层盖度密切相关。灌木层盖度的大小影响幼苗的存活,灌木层盖度小,幼苗存活率高。草本层盖度的大小影响种子的萌发,草本层盖度小,种子萌发率高。在针阔混交林林窗中,当常绿阔叶树稀少或土层浅薄时,思茅松更新个体年龄差异大,当常绿阔叶树长势好且密度较大时,思茅松更新个体年龄普遍差异较小。     

Modified ADM1 for modeling free ammonia inhibition in anaerobic acidogenic fermentation with high-solid sludge

Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid (VFA) production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid sludge fermentation, the anaerobic digestion model No. 1 (ADM1) was modified to simulate the VFA generation in batch, semi-continuous and full scale sludge. The ADM1 was operated on the platform AQUASIM 2.0. Three kinds of inhibition forms, e.g., simple inhibition, Monod and non-inhibition forms, were integrated into the ADM1 and tested with the real experimental data for batch and semi-continuous fermentation, respectively. The improved particle swarm optimization technique was used for kinetic parameter estimation using the software MATLAB 7.0. In the modified ADM1, the K_s of acetate is 0.025, the k_m,ac is 12.51, and the K_{I_NH3} is 0.02, respectively. The results showed that the simple inhibition model could simulate the VFA generation accurately while the Monod model was the better inhibition kinetics form in semi-continuous fermentation at pH 10.0. Finally, the modified ADM1 could successfully describe the VFA generation and ammonia accumulation in a 30 m³ full-scale sludge fermentation reactor, indicating that the developed model can be applicable in high-solid sludge anaerobic fermentation.     

Pesticide exposures and respiratory health in general populations

Human exposures to pesticides can occur in the workplace, in the household and through the ambient environment. While several articles have reviewed the impact of pesticide exposures on human respiratory health in occupational settings, to the best of our knowledge, this article is the first one to review published studies on the association between pesticide exposures and human respiratory health in the general populations. In this article, we critically reviewed evidences up to date studying the associations between non-occupational pesticide exposures and respiratory health in general populations. This article also highlighted questions arising from these studies, including our recent analyses using the data from the Canadian Health Measures Survey (CHMS), for future research. We found few studies have addressed the impact of environmental pesticide exposures on respiratory health, especially on lung function, in general populations. In the studies using the data from CHMS Cycle 1, exposures to OP insecticides, pyrethroid insecticides, and the organochlorine pesticide DDT were associated with impaired lung function in the Canadian general population, but no significant associations were observed for the herbicide 2,4-D. Future research should focus on the potential age-specific and pesticide-specific effect on respiratory health in the general population, and repeated longitudinal study design is critical for assessing the temporal variations in pesticide exposures. Research findings from current studies of non-occupational pesticide exposures and their health impact in general population will help to improve the role of regulatory policies in mitigating pesticide-related public health problems, and thereafter providing greater benefit to the general population.     

聚天冬氨酸-丝氨酸接枝聚合物的合成及阻垢性能

目的研究聚天冬氨酸-丝氨酸接枝聚合物的阻垢性能。方法以聚琥珀酰亚胺为母体,以丝氨酸为接枝单体,合成出聚天冬氨酸-丝氨酸接枝聚合物(PASPSE),采用静态阻垢法分别考察了聚合时间、聚合温度、原料配比对产物阻垢性能的影响。结果聚天冬氨酸-丝氨酸接枝聚合物合成的最佳条件为聚合时间18 h、聚合温度55℃、聚琥珀酰亚胺与丝氨酸原料配比(摩尔比)为1:1。该接枝聚合物对Ca CO3垢具有良好的螯合分散作用,其Ca CO3阻垢率随温度的升高、工作时间的延长、HCO3-与Ca2+含量之比的增大而降低。在90℃高温环境下,10 mg/L PASPSE的阻垢率可达95.5%。结论在高温水系统中,PASPSE对Ca CO3垢具有较好的阻垢性能。     

CANON在SBAF中的快速启动及其微生物特征

启动周期长是单级全程自养脱氮工艺(CANON)的主要制约因素之一.本文研究了基于淹没式生物滤池(SBAF)的CANON工艺的快速启动方法.首先,以城镇污水处理厂二沉池中普通活性污泥为种泥,在(30±2)℃、不添加有机碳源,控制DO(阶段Ⅰ:0.3~0.5 mg·L~(-1),阶段Ⅱ~Ⅳ:0.1~0.2 mg·L~(-1))的实验条件下,经过48 d对污泥微生物的驯化,成功启动了CANON工艺,氨氮(NH+4-N)和总氮(TN)最大去除率分别达到99.9%和86.5%.其次,采用16S r DNA宏基因组高通量测序技术研究了体系内微生物种群结构特性.测序结果显示体系内两个优势微生物菌门是Proteobacteria(变形菌门)和Planctomycetes(浮霉菌门),平均分别占比26.6%和17.8%,主要脱氮微生物是β-Proteobacteria中的Nitrosomonas和Brocadiae中的Candidatus brocadia.通过以上实验分析得出:采用SBAF启动CANON技术,具有可实现体系快速启动、生物高效脱氮、过程稳定运行等特性.     

Effect of scale on flame speeds of methane-air

Explosions are the main types of accidents causing casualties in underground coal mines. Research on the mechanisms of gas explosions is needed as a basis for the development of techniques and strategies for explosion prevention, suppression, and mitigation. The prevention of loss in explosion accidents and inquiries into their causes require understanding of the explosion process of methane in air. Because of the high cost and safety issues in full scale experiments, the experiments with small scale ducts have become a key alternative approach. Whether the experimental results at small scales agree with those at full scales needs to be investigated to validate the significance of the experimental results at small scale. Numerical simulation was used to obtain the explosion characteristics of a methane-air mixture in a gallery or duct. If the grid size is too fine in the numerical simulation for a methane-air explosion it is difficult to calculate using the present computer resource. If the grid size is too coarse, the considerable error may result. The effect of grid size on results of calculation depends on the scenario being investigated. The effect of grid sizes on simulation accuracy was analyzed in this work. The overpressure and temperature distributions and the flame propagation for the deflagration of methane-air mixtures in a gallery or duct were obtained by the AutoReaGas code at three different scales. The geometry of investigated objects and the grids in the calculation domain were similar in the three cases. The calculated overpressures vary with the scale. The calculated temperatures do not vary with the scale for the three cases.