Evaluation of acetylcholinesterase activity in several zooplanktonic crustaceans

Zooplankton are an essential component of the marine and estuarine food chains. The ecotoxicological risk to zooplanktonic communities, estimated through the use of the biomarkers, can be used as an early warning signal of a potential alteration of the ecosystem health. The aim of this project was to evaluate the potential use of several biomarkers (esterases, mixed function oxidases, porphyrins) in zooplanktonic organisms. The acetylcholinesterase activity (AChE) was determined in homogenates of whole organisms of 10 different zooplanktonic crustaceans. Mean activity of AChE was 10.05 micromol/min/g for Acartia margalefi; 3.30 for Acartia latisetosa; 79.70 for Siriella clausi; 49.97 for Diamysis bahirensis; 7.48 for Siriella armata; 14.20 for Mysidopsis gibbosa; 4.49 for Euphausia crystallorophias; 1.66 for Euphausia superba; 2.74 for Streetsia challengeri; 13.26 for Meganycthiphanes norvegica. The species moreover showed a linear increase in enzyme activity in relation to the increase in sample concentration. The key result of this study concerns the different AChE activity basal values of the crustaceans' different species.     

Phytoremediation of small-scale oil spills in fresh marsh environments: a mesocosm simulation

Research was conducted to assess the impact of oiling on fresh-marsh plant communities and to test the efficacy of techniques that may be used to enhance the bioremediation of crude oil spills in these environments while minimizing secondary anthropogenic impacts. To emulate field conditions, a mesocosm facility was used that houses 120 mesocosm vessels, each of 200-1 capacity. A five-way factorial treatment arrangement was used that included two substrates (inorganic, organic), two nutrient regimes (fertilized, not fertilized), two aeration levels (substrate aeration, no aeration), three oiling concentrations (0-, 5-, 10-1 m(-2) of South Louisiana Sweet Crude oil), and four vascular plant species (Alternanthera philoxeroides, Panicum hemitomon, Phragmites australis, Sagittaria lancifolia, and an unplanted control). Under the 5- and 10-1 m(-2) oiling concentrations, S. lancifolia displayed a short-term response of increased productivity, whereas P. hemitomon had the highest biomass production and photosynthetic rates at the end of the 18-month experiment. Overall plant growth and productivity, as well as oil degradation, were significantly higher in the inorganic substrate, indicating that biodegradation of oil spills in organic substrates may require a longer time period. Time-released fertilizer also stimulated plant productivity and resulted in higher soil respiratory quotients, suggestive of greater microbial activity, particularly in aerated mesocosms. The amount of oil remaining after 18 months was lowest in aerated and fertilized mesocosms containing either P. hemitomon or S. lancifolia and a substrate of low organic matter content.     

活性水系沉积物的冻结采样技术应用于矿产勘查及环境研究

本文比较了活性水系沉积物的冻结采样技术与常规采样技术，经统计分析，１０种氧化物和２１种微量元素在两种技术之间全部都存在着显著的差异。在１２２个采样点上所得到的氧化物重量百分比和微量元素含量表明：冻结采样可得到具有代表性的沉积物样品。每个采样点为了获得对沉积物中氧化物重量百分比和元素含量具有代表性的评估，需要小于５０％的冻结样品，相反，常规采样由于冲洗和淘洗细粒级沉积物，致命用以常规地球化学分析的沉     

在鄂霍茨克——楚克奇火山矿床中的金—冰长石—石英集合体

含金的冰长石－石英集合体是金银矿化的指示剂，它们在区域矿床系列中，并在的集合体的结构，石英及冰长石典型的化学键和金矿堆积作用中，具有统一的规律性。     

A comparison of solute-transport solution techniques and their effect on sensitivity analysis and inverse modeling results

Five common numerical techniques for solving the advection-dispersion equation (finite difference, predictor corrector, total variation diminishing, method of characteristics, and modified method of characteristics) were tested using simulations of a controlled conservative tracer-test experiment through a heterogeneous, two-dimensional sand tank. The experimental facility was constructed using discrete, randomly distributed, homogeneous blocks of five sand types. This experimental model provides an opportunity to compare the solution techniques: the heterogeneous hydraulic-conductivity distribution of known structure can be accurately represented by a numerical model, and detailed measurements can be compared with simulated concentrations and total flow through the tank. The present work uses this opportunity to investigate how three common types of results--simulated breakthrough curves, sensitivity analysis, and calibrated parameter values--change in this heterogeneous situation given the different methods of simulating solute transport. The breakthrough curves show that simulated peak concentrations, even at very fine grid spacings, varied between the techniques because of different amounts of numerical dispersion. Sensitivity-analysis results revealed: (1) a high correlation between hydraulic conductivity and porosity given the concentration and flow observations used, so that both could not be estimated; and (2) that the breakthrough curve data did not provide enough information to estimate individual values of dispersivity for the five sands. This study demonstrates that the choice of assigned dispersivity and the amount of numerical dispersion present in the solution technique influence estimated hydraulic conductivity values to a surprising degree.     

关于中国地理学中的区域综合研究

综合性与区域性是地理学的两大基本特点。随着区域发展成为人们关注的热点,跨学科综合研究成为学科发展趋势,我国的区域综合研究势在必行。我国地理学的发展历程和当今研究现状亟须区域综合研究的根本性突破,才能更好地为全球层面上的全球环境变化、国家层面上的可持续发展以及地区层面上的社会经济发展服务,才能推动地理学理论创新,真正实现黄秉维先生所倡导的"综合指导下分析,分析基础上综合"的方法论应用。最后,依据我国地域特征,拟定8个典型区域作为近期综合研究区,并提出加快研究云贵高原喀斯特地区的倡议。