有机磷农药毒性预测模型研究

选用化合物分子拓扑学的信息理论指数、价分子连接性指数，运用多元非线性回归分析，对１１４种有机磷农药大鼠经口、小鼠经口及大鼠经皮急性毒性ＬＤ５０、神经毒性作用进行了定量预测分析。回归模型相关指数Ｒ＾２均在０．８１以上，残差呈正态分布，预测效果满意，显示了系统具有较强的预测能力。     

Effects of elevated CO2 concentration on growth and water usage of tomato seedlings under different ammonium/nitrate ratios

Increasing atmospheric CO2 concentration is generally expected to enhance photosynthesis and growth of agricultural C3 vegetable crops, and therefore results in an increase in crop yield. However, little is known about the combined effect of elevated CO2 and N species on plant growth and development. Two growth-chamber experiments were conducted to determine the effects of NH4^＋/NO3^- ratio and elevated CO2 concentration on the physiological development and water use of tomato seedlings. Tomato was grown for 45 d in containers with nutrient solutions varying in NH4^＋/NO3^- ratios and CO2 concentrations in growth chambers. Results showed that plant height, stem thickness, total dry weight, dry weight of the leaves, stems and roots, G value （total plant dry weight/seedling days）, chlorophyll content, photosynthetic rate, leaf-level and whole plant-level water use efficiency and cumulative water consumption of tomato seedlings were increased with increasing proportion of NO3- in nutrient solutions in the elevated CO2 treatment. Plant biomass, plant height, stem thickness and photosynthetic rate were 67%, 22%, 24% and 55% higher at elevated CO2 concentration than at ambient CO2 concentration, depending on the values of NH4^＋/NO3^- ratio. These results indicated that elevating CO2 concentration did not mitigate the adverse effects of 100% NH4^＋-N （in nutrient solution） on the tomato seedlings. At both CO2 levels, NH4^＋/NO3^- ratios of nutrient solutions strongly influenced almost every measure of plant performance, and nitrate-fed plants attained a greater biomass production, as compared to ammonium-fed plants. These phenomena seem to be related to the coordinated regulation of photosynthetic rate and cumulative water consumption of tomato seedlings.     

A review on molecular topology: applying graph theory to drug discovery and design

Molecular topology is an application of graph theory and statistics in fields like chemistry, biology, and pharmacology, in which the molecular structure matters. Its scope is the topological characterization of molecules by means of numerical invariants, called topological indices, which are the main ingredients of the molecular topological models. These are statistical models that are instrumental in the discovery of new applications of naturally occurring molecules, as well as in the design of synthetic molecules with specific chemical, biological, or pharmacological properties. In this review, we focus on pharmacology, which is a novel field of application of molecular topology. Besides summarizing some recent developments, we also seek to bring closer this interesting biomedical application of mathematics to an interdisciplinary readership.

Do energy efficiency standards hurt consumers? Evidence from household appliance sales

We build novel welfare-based price indices for major household appliances that leverage changes in same-model prices and how consumers substitute between exiting, continuing and new models. We then evaluate how minimum energy efficiency requirements and changing criteria for Energy Star™ labels affected these indices in the U.S. between 2001 and 2011, a period of time when some appliances experienced standard changes while others did not. We find that prices declined while quality and consumer welfare increased, especially when standards become more stringent. We also find that much of the price index decline can be attributed to standards-induced innovation, or cannibalism, not to inter-manufacturer competition. Our results also add to a growing body of evidence that the Consumer Price Index exaggerates inflation due to inadequate account of quality and substitution to new goods.     

基于IOCS的内蒙古潜在植被NPP空间分布特征研究

以综合顺序分类系统(IOCS)为基础,利用1985-2009年内蒙古及周边常规气象站的观测资料,采用NPP分类指数模型模拟内蒙古各潜在植被类型NPP,分析其空间分布特征及NPP与气候因子之间的关系。研究表明:①内蒙古地区植被NPP在空间分布上表现出一定的经向分布特征,多年均值介于0~366.5 gC·m^-2·a^-1之间,高值区中心分布在大兴安岭东北部;②各潜在植被类型中,碳汇潜力贡献率最大的潜在植被类型为微温微干温带典型草原类(ⅢC),其值为23.6%;最小的为寒温微干山地草原类(ⅡC),接近于0;③内蒙古潜在植被类型NPP表现出明显的干湿地带性和纬度地带性,且随寒温→微温→暖温、微干→微润→湿润→潮湿的变化其NPP值逐渐增大;但暖温极干暖温带荒漠类(ⅣA)和暖温干旱暖温带半荒漠类(ⅣB)并不符合这一规律,主要原因是较高的温度和较少的降水,达不到植被物质生长的需求。     

On the consequences of aggregation and balancing of networks on system properties derived from ecological network analysis

In the ecological network analysis (ENA) of complex flow food webs the assumption is often made that the models characterizing the flows and stocks of ecosystems occur in a steady state where inflows equals outflows. An assessment of the system indices derived from ENA of six balanced and unbalanced system models, respectively, indicate to differences between indices. The aggregation of highly articulated flow models into models with fewer compartments also has drastic effects on the system metrics, particularly on the information indices.     

Rapana venosa as a bioindicator of environmental pollution

The aim of this investigation was to examine biochemical differences in the gastropod Rapana venosa (R. venosa) from polluted (RvP) and nonpolluted (RvN) sites of the Black Sea's Bulgarian coast that may serve as bioindicators of environmental quality. Mussels Mytilus galloprovincialis (MMg) were collected from polluted (MMgP) and nonpolluted (MMgN) sites at the same time for comparison. Bioactive compounds and the antioxidant activity of dry matter (DM) methanol extracts from RvP and RvN were determined. Three-dimensional fluorometry (3D-FL) and Fourier transform infrared (FTIR) analyses were used to evaluate polyphenols and proteins. DM methanol extracts from RvP, and to lesser extent RvN, showed high amounts of total phenolics (23.22±2.9 and 15.60±1.8 mg GAE · g^?1 DW) and exhibited high levels of antioxidant activity in some radical scavenging assays (μ MTE · g^?1 DW): 56.38±5.2 and 33.79±3.3 by 2,2azino-bis (3-ethyl-benzothiazoline-6-sulfonic acid) diamonium salt (ABTS·⁺); 54.79±5.6 and 33.7±2.6 by cupric reducing antioxidant capacity (CUPRAC); 62.34±6.8 and 30.31±3.9 by the 1diphenyl-2-picrylhydrazyl method (DPPH). A correlation in the above indices was found between R. venosa and M. galloprovincialis, but all results were relatively higher for M. galloprovincialis than for R. venosa. The obtained indices of R. venosa may serve as a bioindicator of environmental ecological quality.     

信息理论指数及其在有机磷农药毒性预测研究中的应用

为探讨化合物结构与毒性关系研究方法,将定量描述分子结构特征的信息理论指数、价分子连续性指数应用于有机磷农药毒性预测研究,提出了基团信息参数。运用判别分析、多元非线性回归分析,依据１１４种有机磷农药急性毒性数据资料,按动物不同给药途径,分别建立定性、定量预测模型,定性判别回代符合率均在８３．３３％以上,定量回归方程相关指数Ｒ＾２均在０．８１以上,回归残差呈正态分布。预测分析,预测值均在ＬＤ５０测定值     

城市主要功能用地景观格局的演变特征——以江苏省淮安市为例

基于GIS平台,提取了淮安市主城区城市用地的矢量数据,借助Fragstats3.3软件,计算了主要功能用地的景观格局指数,并对城市功能用地景观格局演变的特征进行了分析。研究表明：自1982年以来,城市功能用地斑块数量增多,斑块面积逐渐增大,面积差异不断缩小,用地斑块空间聚集程度渐渐上升,连通性水平逐步提高,功能用地斑块的形状特征与规整性变化明显;居住用地呈现出大分散、小集中的空间格局特征,斑块面积由小变大,斑块之间距离增大,密度降低,用地斑块的规整性与形态变化较大;工业用地由分散布局逐渐趋向于集中,斑块面积规模由小变大,完整性与集聚程度不断提高,相互连通性明显增强,斑块形态复杂性低;城市公共设施用地表现出大分散、小集中特点,用地斑块面积由大变小,面积差异较大,斑块形态与规整性变化明显     

中国环境友好型社会评价体系构建与应用

根据环境友好型社会的内涵和建设途径，遵循指标体系构建原则，结合中国实际，建立了一套包括3个层次31个指标的环境友好型社会综合评价指标体系。根据所选定的指标体系。利用多目标二级决策法和变异系数法对一、二级指标确定权重，并运用TOPSIS法对中国各地2004年的环境友好型社会建设水平进行了排序、评价。结果表明：各地环境友好型社会建设水平普遍不高，与经济发展水平有一定的正相关性，地域格局上呈现出东部、东北、中部、西部依次递减的趋势；环境友好型社会建设水平的区域差异主要表现在地带间的差异。