A Method for Forecasting the Dates of Mass Calving and Some Characteristics of the Rut and Calving in the Kalmyk Population of Saiga (Saiga tatarica L.)

A method for forecasting the dates of calving in the saiga population on the basis of average fetal body weight is proposed. The method is based on the relationship between the number of days before calving and the average weight of fetuses, which obviates the necessity of determining fetal age and exact gestation period in this species. The average length of gestation, the dates of the rut in the years studied, and the age of females that have mated immediately upon the onset of the rut and before its cessation have been determined. It is shown that the duration of mass calving depends on the proportion of mature males in the population.     

我国人口问题与可持续发展

人口因素在“人口、资源、环境、经济、社会”可持续发展系统中处于中心地位。本文从可持续发展角度，探讨了我国人口数量、质量、结构、分布等方面存在的问题，并对其优化方向作了简要分析。     

基于需求与供给理论的甘肃省人口土地承载力研究

从供给和需求平衡的经济学视角,运用生态能值分析的研究方法,对2006年-2012年甘肃省农业土地人口承载力进行了实证研究.发现中国取消农业税政策提高了农民生产积极性,同时发现近年来甘肃省农业土地能值供给无法满足人口能值需求,但供需差距在缩小,预计未来十数年内随着农业产业化生产及农业科技的提高,甘肃省将实现农业土地产出和人口能值需求的自给自足.     

A Review of the United States' Past and Projected Water Use

Good information and data on water demands are needed to perform good analyses, yet collecting and compiling spatially and temporally consistent water demand data are challenges. The objective of our work was to understand the limitations associated with water‐use estimates and projections. We performed a comprehensive literature review of national and regional United States (U.S.) water‐use estimates and projections. We explored trends in past regional projections of freshwater withdrawals and compared these values to regional estimates of freshwater withdrawals made by the U.S. Geological Survey. Our results suggest a suite of limitations exist that have the potential for influencing analyses aiming to extract explanatory variables from the data or using the data to make projections and forecasts. As we explored regional projections, we paid special attention to the two largest water demand‐side sectors — thermoelectric energy and irrigation — and found thermoelectric projections are more spread out than irrigation projections. All data related to water use have limitations, and there is no alternative to making the best use that we can of the available data; our article provides a comprehensive review of these limitations so that water managers can be more informed.     

四种溶剂对土壤中芴的提取及HPLC检测比较研究

多环芳烃(PAHs)作为一类具有健康风险的疏水性有机污染物,近年来在土壤中被频繁检出。高效液相色谱法(HPLC)可以在同一条件下同时检测环境中多种PAHs,然而为了更好地定量分析,需要研究针对某一种PAH更加精准的HPLC检测条件。以常见的PAHs——芴作为研究对象,分别以乙酸、丙酮、乙醇和甲醇为溶剂配制了0~60 mg/L的芴溶液,用HPLC法检测溶液中的芴,在不同条件下得到了相关系数为0.9990~1.0000的标准曲线;研究将芴附着到土壤及将其从土壤中提取时机械振荡时间对4种溶剂提取芴的影响,得出附着最佳振荡时间为10 h,提取最佳振荡时间为1 h;探究了机械振荡法提取土壤中的芴时4种溶剂的提取率,提取率为乙酸>丙酮>乙醇>甲醇。     

Trends of SO2emission in the European union, 1985–1997

The trends of yearly emission of sulphur dioxide are analysed for the European Union during a period of time from 1985 to 1997. To achieve the above matter the method of the least squares model has been used. Major SO₂emissions were found in Germany, the United Kingdom, Spain, Italy and France. However, high SO₂emissions by km²were found in Germany, the United Kingdom and Belgium. The most remarkable results of the trend analysis appears as follows: 12 countries with significant downward trends, 2 countries with significant upward trends and 1 country with no significant trend. A decreasing trend is evident for the most part of the E.U., although Portugal and Greece generated significant increasing trends of SO₂emission for the mentioned year period.     

经济、环境与人口健康的相互影响:基于我国省区面板数据的实证分析

经济增长造成环境变化;收入水平和环境质量共同影响着人口健康;人口健康状况又影响着经济增长.本文构建了一个描述兰者之间关系的联立方程模型,使用省区面板数据.分析了我国20世纪90年代至今省区层面上经济、环境与人口健康的相互影响.实证结果表明,工业污染是经济增长的阻碍因素;经济增长对人口健康有显著的正影响,而工业污染对人口健康有显著的负影响;人口健康对经济增长的贡献不显著;教育状况对经济增长有显著促进作用,但对人口健康没有显著的直接影响;第三产业的发展有利于减少工业污染,改善环境质量.因此,发展教育事业和第三产业,是促进经济增长和提高环境质量的有效举措.     

Demographic Characteristics of Extinction in a Small, Insular Population of House Sparrows in Northern Norway

Abstract:  In conservation ecology there is an urgent need for indicators that can be used to predict the risk of extinction of populations. Identifying extinction-prone populations has been difficult because few data sets on the demographic characteristics of the final stage to extinction are available and because of problems in separating out stochastic effects from changes in the expected dynamics. We documented the demographic changes that occurred during the period prior to extinction of a small island population of House Sparrows ( Passer domesticus ) after the end of permanent human settlement. A mark-recapture analysis revealed that this decline to extinction was mainly due to increased mortality after closure of the last farm that resulted in a negative long-term-specific growth rate. No change occurred in either the structural composition (breeding sex ratio and age distribution) of the population or in female recruitment. No male, however, recruits were produced on the island after the farm closure. Based on a simple, stochastic, density-dependent model we constructed a population prediction interval (PPI) to estimate the time to extinction. The 95% PPI slightly overestimated the time to extinction with large uncertainty in predictions, especially due to the influence of demographic stochasticity and parameter drift. Our results strongly emphasize the importance of access to data on temporal variation that can be used to parameterize simple population models that allow estimation of critical parameters for credible prediction of time to extinction.     

人口结构、社会保障与机构投资者的发展——以发达国家为例

近年来我国的经济发展中出现了居民的存款储蓄不断增长与企业资金短缺、股票市场低迷并存的现象。发达国家的经验表明,社会保障制度与金融发展具有明显的相关性：社会保障制度的改革与发展。改变了居民以存款为主体的金融资产结构。使居民金融资产的选择从直接持有转向通过养老金、保险金和共同基金等机构投资者的间接持有，促进了机构投资者的迅猛发展；而机构投资者的资产越来越多的投向了证券资产。进而促进了资本市场的进一步发展。     

Population cycles of the bank vole in the range optimum

Patterns of seasonal and long-term dynamics of the size and structure of the bank vole population were studied in the European subtaiga subzone, the optimum of the species range. The dynamics of this population proved to undergo complex fluctuations with cyclic components, which have periods of one year and about three years. The one-year fluctuations of the population size and structure are accounted for by animal adaptation to seasonal changes in environmental factors. The fluctuations with the three-year quasi-period are determined by intrapopulation density-dependent mechanisms.