广东省城镇居民消费结构变动的定量分析

利用扩展的线性支出系统(ELES),依据1997年及2003年广东省城镇居民年人均可支配收入和消费支出的截面数据,对广东城镇居民消费结构的变动情况进行定量分析。分析结果表明,广东城镇居民在“衣”和“食”得到满足之余,越来越重视对“住”与“行”的消费,同时,对精神文化、教育、交往联络、自身健康和保健也越来越关注,并提出了促进广东城镇居民消费结构优化和升级的几点建议。     

温度对橄榄蛏蚌耗氧率和排氨率的影响

在室内实验条件下研究了温度对不同规格橄榄蛏蚌耗氧率和排氨率的影响。实验结果表明, 15~30℃下,橄榄蛏蚌耗氧率和排氨率为大规格组均小于小规格组。耗氧率和排氨率与橄榄蛏蚌软体部干重(W)呈现明显的幂函数关系。在实验温度(15~30℃)范围内,随温度的上升,橄榄蛏蚌的耗氧率和排氨率均先逐渐增加,后随之下降,两者的高峰值分别出现在25℃和20℃。耗氧率(O)、排氨率(N)与温度(T)和橄榄蛏蚌软体部干重(W)的二元线性回归方程分别为:O=-0 .651 3+0. 053 2T+0. 107 3W,N=32. 162 6-1. 056 6T+1 .322 2W。二方程复相关系数r分别为0 .964 2和0 .892 1;F检验分别为极显著和显著。     

Extreme spatial variations in crime density in Baltimore County, MD

A salient characteristic of the geography of crime in the US is the presence of extremely sharp geographic variations. These variations may be significant indicators of local environmental inequalities and may have implications for fear of crime and crime contagion, and may also be indicators of potential or actual neighborhood instability. Such micro-level variations are not generally apparent on small scale maps of urban crime. Previously, micro-level analysis of this gradient phenomenon has been inhibited by the confluence of large volumes of data over large areas, a plethora of possible boundaries that might be used for the purpose of data aggregation, and practical difficulties in the identification of gradients in the context of small units of analysis. The present study attempts to identify steep crime gradients and to characterize the physical and social circumstances under which they occur. Analysis was based on 97,880 geocodable incidents reported in 2000 in Baltimore County, Maryland. Crime densities were calculated for 5324 census blocks that experienced at least one crime incident. A steep gradient for the purpose of this research was the juxtaposition of blocks in the highest and lowest quintiles in terms of crime density. Using residential and commercial land uses as a filter, some 259 blocks satisfied the gradient criterion. Further analysis linked these blocks to their parent block groups for the purpose of identifying their social attributes. In addition, six clusters of blocks were investigated in the field. A typology of adjacencies identified six categories.     

Seasonal changes in the distribution and exchange of inorganic nitrogen between sediment and water in the Northern Baltic (Gulf of Bothnia)

The concentration profiles of nitrate plus nitrite, ammonium, and redox potential in sediment and water column were determined in late winter and summer at a sampling site off Norrbyn, northern Sweden, in the Gulf of Bothnia. The sediment had an oxidized surface layer during winter and spring, and nitrification occurred. Nitrate but not ammonium was present in the water column at this time. During summer a layer of planktonic detritus was deposited onto the sediment and led to its deoxygenation and reduction. Ammonium was then the predominant form of inorganic nitrogen in the water column.Laboratory experiments confirmed that nitrification in the surface layer of sediment prevented ammonium export during winter. Enhanced temperature or organic detritus deoxygenated the surface sediment and inhibited nitrification, and export of ammonium from the sediment increased. Although nitrification was important in determining the flow of nitrogen in the sediment it accounted for at most only 5% of the total oxygen uptake by the sediment.     

STUDY ON THE DYNAMIC PROCESS OF RILL EROSION OF LOESS SLOPE SURFACE

1 mTRODUCTIONAs a woridwide concem, excessive water erosion induces land degradation, causes losses of plantnutrients, and Ieads to off site enVironmental problems such as sedimentahon streams and reservoirs. mllerosion, which results from concentraed flow in a lindted and confined space, plays imPortant roles inthe erosion systCm on uPland areas. Data listed in Table l show its contribution and imPoftance to thetOtal slope soil losses. In the last decades, stodies on the physical mecha…     

粘土矿物碱耗协同效应研究

选择蒙脱石,高岭石,伊利石等三种在储层中最党风的储层粘土矿物,两两分别按２Ｌ：０,１：１,０：２质量配比组成复配物系列;在３０℃、５０℃温度下按１：５,１：８,１：１０（ｇ／ｍｌ）固／液比分别与１．６％的Ｎａ２ＣＯ３深液反应８ｈ,３６０ｈ;监测反应前后碱液浓度的变化;计算了各条件下各自的绝对碱耗量。结果表明三种粘土矿物中蒙脱石耗碱最大,高蛉石的耗碱量与伊利石的接近;随着固／液比减小和温度升高,矿物     

转型期广州市城市居民住房产权分异研究

利用社会-人口统计学研究方法,以问卷调查结果为基础,从自置房和租赁房、资助房和商品房两个层面,分析住房产权分异影响因素,研究发现社会经济特征变量与组织变量对住房产权分异都有显著影响,尤其是组织变量对资助房与商品房产权分异的影响更显著.家庭社会经济特征,如户主年龄、婚姻状况、家庭规模和家庭收入对产权分异的影响基本与西方类似.国有单位和工龄长的职工,享受资助房的机会相对较多.目前的住房制度改革集中在住房的私有化和大规模的商品房开发建设上,应更加关注新形势下住房分配的不平等.     

中国能源消费与气候变化的关系

Energy consumption has an inevitable connection with economic level and climate. Based on selected data covering annual total energy consumption and its composition and that of all kinds of energy in 1953-1999, the annual residential energy consumption and the coal and electricity consumption in 1980-1999 in China, the acreage of crops under cultivation suffered from drought and flood annually and gross domestic product (GDP) in 1953-1999 in the whole country, and mean daily temperature data from 29 provincial meteorological stations in the whole country from 1970 to 1999, this paper divides energy consumption into socio-economic energy consumption and climatic energy consumption in the way of multinomial. Itchanges between the climate energy consumption andalso goes further into the relations and their changes between the climate energy consumptionenergy consumption and the economic level inand climate factor and between the socio-economic energy between the climate energy level in China with the method of statistical analysis. At present, there are obvious transitions in the changing relationships of the energy consumption to economy and climate, which comprises the transition of economic system from resource-intensive industry to technology-intensive industry and the transition of climatic driving factors of the energy consumption from driven by the disasters of drought and flood to driven by temperature.     

黑河中游二白杨叶面积指数动态变化及其与耗水量的关系

在黑河中游,利用直接法和热脉冲树干液流仪分别监测了二白杨生长季节的叶面积指数和耗水量动态变化,研究了二白杨叶面积指数动态变化规律及其与耗水量的关系.结果表明:在生长季节,二白杨叶面积指数的增长符合Logistic模型;在树冠结构垂直分布上,1 000~1 400 cm之间二白杨叶面积指数占全树叶面积指数的75.5%;二白杨个体间的叶面积指数与胸径平方和树高乘积呈指数函数关系.当单株叶面积指数从0.44增大到4.94时,二白杨耗水量从42.95 L·d^-1增加到140.30 L·d^-1.单株二白杨耗水量与叶面积指数之间呈现线性关系.     

Major ion chemistry of two cratonic rivers in the tropics: Weathering rates and their controlling factors

Continental weathering plays a dominant role in regulating the global carbon cycle, soil chemistry and nutrient supply to oceans. The CO₂-mediated silicate weathering acts as a major CO₂ sink, whereas sulphuric acid-mediated carbonate dissolution releases CO₂ to the atmosphere–ocean system. In this study, dissolved major ions and silica concentrations of two tropical (Damodar and Subarnarekha) river systems from India have been measured to constrain the type and rate of chemical weathering for these basins. The total dissolved solids (TDS) of these rivers, a measure of total solute supply from all possible sources, are about 2–3 times higher than that of the global average for rivers. Mass balance calculations involving inverse modelling estimate that 63 ± 11% of total cations are derived from rock weathering, of which 27 ± 7% of cations are supplied through silicate weathering. The sulphide-S concentrations are estimated by comparing the water chemistry of these two rivers with that of a nearby river (Brahmani) with similar lithology but no signatures of sulphide oxidation. The outflows of Damodar and Subarnarekha rivers receive 17% and 55% of SO₄ through sulphide oxidation, respectively. The sulphide oxidation fluxes from the ore mining areas, such as upper Damodar (0.52 × 10⁹ mol/yr) and lower Subarnarekha (0.66 × 10⁹ mol/yr) basins, are disproportionally (~9 times) higher compared to their fractional areal coverage to the global drainage area. The corresponding CO₂ release rate (2.84 × 10⁴ mol/km²/yr) for the Damodar basin is lower by five times than its CO₂ uptake rate (1.38 × 10⁵ mol/km²/yr). The outcomes of this study underscore the dominance of sulphide oxidation in controlling the dissolved chemical (cationic and sulphur) fluxes.