安徽省农民人均纯收入地域差异及其原因分析

以SPSS V13．0、Excel、Eviews 3．1和ArcView GIS3．2为工具，运用层次聚类分析和相关分析等方法，分析了安徽省农民人均纯收入的地域差异以及引起地域差异的原因。结果表明，安徽省农民人均纯收入的地域分异由东南向西北递减，并与经济发展水平区内分异性相吻合，这种差异是由自然条件差异和社会条件差异共同造成的。本研究对安徽省农村区域发展均衡性具有一定的指导意义。     

MULTITEMPORAL SCALE HYDROGRAPH PREDICTION USING ARTIFICIAL NEURAL NETWORKS1

Abstract: An artificial neural network (ANN) provides a mathematically flexible structure to identify complex nonlinear relationship between inputs and outputs. A multilayer perceptron ANN technique with an error back propagation algorithm was applied to a multitime-scale prediction of the stage of a hydro-logically closed lake, Devils Lake (DL), and discharge of the Red River of the North at Grand Forks station (RR-GF) in North Dakota. The modeling exercise used 1 year (2002), 5 years (1998–2002), and 27 years (1975–2002) of data for the daily, weekly, and monthly predictions, respectively. The hydrometeorological data (precipitations P_(t), P_(t-1), P_(t-2), P_(t-3), antecedent runoff/lake stage R_(t-1) and air temperature T_(t) were partitioned for training and for testing to predict the current hydro-graph at the selected DL and RR-GF stations. Performance of ANN was evaluated using three combinations of daily datasets (Input I = P_(t)), P_(t-l), P_(t-2), P_(t-3), T_(t) and R_(t-l); Input II = Input-l less P_(t) P_(t-l), P_(t-2), P_(t-3); and Input III = Input-II less T_(t)). Comparison of the model output using Input I data with the observed values showed average testing prediction efficiency (E) of 86 percent for DL basin and 46 percent for RR-GF basin, and higher efficiency for the daily than monthly simulations.     

Questionable accountability: MSF and Sphere in 2003

This article examines the relationship between Médecins Sans Frontières (MSF) and the Sphere Project. Prior to revisiting the concerns MSF had with the project, it looks at factors that give rise to differences between NGOs and cites some reasons for why an organisation such as MSF would not embrace such a project and clarifies some key elements of MSF-style humanitarianism. The author revisits the original concerns and arguments presented by MSF when it decided not to participate beyond assisting with the establishment of technical standards and key indicators for the handbook. This is followed by a critical discussion examining these concerns and counter-criticism with reference to experiences a few years after the inception of Sphere. It concludes with MSF's perceptions and stance regarding Sphere and accountability in 2003.     

中国区域可持续发展水平的时空分异初探

本文通过因子分析,建立了中国可持续发展的因子结构模型,指出：（1）社会经济发展呈现“丁”字型格局;（2）环境污染东、中部严重,西部较轻;（3）生态退化西重东轻,北重南轻;（4）中国“环境与发展”时序上大致呈现“U”字型规律,29个省市分别与“U”曲线的逆向非同速（加速）阶段、同向非同速（加速）阶段、同向非同速（减速）阶段在地域上联系起来。     

红枫湖水体中活性汞和溶解气态汞的分布特征及其控制因素

基于二次金汞齐结合冷原子荧光测定法对红枫湖活性汞(RHg)和溶解气态汞(DGM)的时空分布特征及其控制因素进行了研究. 红枫湖溶解气态汞含量(ρ(DGM))为0.024～0.110 ng/L,随着水深的增加ρ(DGM)降低,且夏季高,冬季低,这种分布特征表明光在原子态汞的形成中起着重要的作用. 红枫湖ρ(DGM)除受光强影响外,还受到春季后五大量生长的藻类影响,但与溶解性有机碳含量(ρ(DOC))及温度的相关性不大. 活性汞含量(ρ(RHg))为0.14～2.70 ng/L,其主要受Hg2+的光致还原过程,Hg2+的甲基化过程以及人为源的释放等因素的控制.      

Contradictory results in sex ratio studies: populations do not necessarily differ

In avian sex ratio studies, results often differ between species and between populations within species. Some researchers argued that positive results were simply statistical artefacts and that sex ratio adjustment did not exist. However, many of the proposed mechanisms of sex ratio adjustment result in costly laying gaps. In these cases, females laying large clutches may restrict the sex manipulation to the first egg of the clutch. Consequently, detectability of sex ratio adjustment on the level of the clutch can be low. Though obvious, this fact is often neglected in the literature. Using simulations, I show that the proportion of undetected sex manipulation can be surprisingly high when the manipulation is restricted to the first egg. If the sample size is 50 broods, there is 47% and 71% chance in 6- and 12-egg clutches, respectively, that sex manipulation is undetected. Even with large samples (n = 100), the figures are 15% and 46%. These data suggest that nonsignificant results for clutch sex ratios do not necessarily mean that sex is not manipulated in a portion of the brood, e.g. in first-laid eggs. Hence, whenever possible, data on laying order-specific sex manipulation should also be collected. Without such data, contradictory results on brood sex ratios should be interpreted cautiously.     

我国西南地区1960～2000年降水资源变化的时空特征

利用我国西南地区96个测站近40a的月降水量资料,采用主成分分析、旋转主成分分析、小波分析等方法对西南地区年降水资源变化的时空特征进行了分析。结果表明:近40a西南地区的西部高原地区降水资源呈增加趋势,而东部除重庆地区外,大部分地区降水资源减少。西南地区年降水资源空间特征复杂,存在南北和东西相反变化的差异,空间异常可分为8个异常区,即滇南区、川西高原区、滇黔交界区、四川盆地东部、四川盆地西部、滇西区、黔渝交界区和凉山区。西部高原地区年降水量都经历了多雨-少雨-多雨的过程,20世纪90年代降水量呈增加的趋势,四川盆地东部经历了少雨-多雨-少雨的过程,四川盆地西部和整个西南地区东南部的降水量整体都呈下降趋势。川西高原区、滇南区和滇黔交界区在整个时段存在显著的准14a周期,其他异常区的显著周期及其年代变化有较大差异。     

人工湿地基质中酶活性和细菌生理群的时空动态特征

对复合垂直流人工湿地基质中6种酶酶活性和5种细菌生理类群数量进行了测定.结果表明各种酶酶活性在不同月份存在显著差异(p<0.05):纤维素酶、蛋白酶和磷酸酶在6月、9月和12月时都表现出较高的酶活性,并且都显著地高于3月的酶活性;β-葡萄糖苷酶在6月时酶活性显著地高于其它月;而脲酶活性在9月和12月时极显著地高于3月和6月(p<0.01);脱氢酶酶活性在6月和12月时明显高于3月和9月.相比较而言,6种酶酶活性的空间特征较为一致,下行流池酶活性显著高于上行流池活性(p<0.05),并且随着基质层深度的增加,酶活性亦相对递减.细菌生理类群数量在6月和9月达到高峰,并且所反映出来的空间规律与酶活性有一致性.     

长江上游支流老河沟鱼类群落结构的时空格局

2012年3月、6月、9月和12月按季度对涪江支流老河沟的14个样点进行了鱼类群落结构调查和分析。共采集鱼类11种,隶属于2目4科;其中,鲤形目鱼类7种,占物种数的63.64%。沿上游源头到下游的纵向梯度方向,老河沟鱼类的种类数和丰度均逐渐增加,具极显著性差异,而鱼类种类数和丰度则无季节差异性。聚类分析(Cluster Analysis)和多维尺度分析(MDS)表明,当Bray-curtis相似度矩阵值为40.77%时,老河沟鱼类群落分成上游、中游和下游3组。利用相似度百分比分析(SIMPER)确定,引起3组差异性的特定鱼类是宽鳍鱲、尖头、似()、齐口裂腹鱼、贝氏高原鳅、红尾荷马条鳅和青石爬鮡。典型相关分析(CCA)表明海拔、底质类型、流速、溶氧、总溶解固体、水温、电导率、河宽、pH值和水深等环境变量是老河沟鱼类群落时空格局差异的影响因子。     

气候变化对中国夏季臭氧影响

气象条件对近地层臭氧(O₃)的生成有重要影响.为了探讨未来气候变化如何影响中国不同地区的O₃浓度,本研究将全球耦合模式比较计划CMIP5提供的CESM地球系统模式的气候预测数据作为WRF区域气象模式的初始边界条件,降尺度模拟了3种代表情景(RCP4.5、 RCP6.0和RCP8.5)下的未来2046～2055年夏季气候变化情况,并驱动CMAQ区域空气质量模式模拟气候变化对O₃的影响.结果表明,气候变化使中国夏季边界层高度、温度均值和高温天数增加,相对湿度有所降低,近地面风速无明显变化.在气象要素的共同影响下,O₃浓度在京津冀、四川和华南等地区呈现增加趋势,O₃每日最大8 h滑动平均(MDA8)极值在不同情景下增幅为：RCP8.5(0.7μg·m^-3)>RCP6.0(0.3μg·m^-3)>RCP4.5(0.2μg·m^-3).夏季MDA8超标日变化与高温天数变化有较为相似的分布,MDA8超标的发生与高温天...