同离子效应和温度场对裂缝中酸液有效作用距离的影响

酸液有效作用距离是酸压设计的重要参数,也是影响酸压效果的重要因素。酸液中的反应产场(同离子)和裂缝中温度分布对酸液沿裂缝流动时的有效作用距离影响很大。到目前为止,尚未见到研究同离子效应和温度场对酸液有效作用距离综合影响的文章。本文从酸压设计计算的实际需要出发,考虑影响酸液有效作用距离的主要因素,建立裂缝中酸岩流动反应数学模型,并将该模型与裂缝中温度分布模型、速度场模型和表面反应动力学模型联立求解,编制电算程序,进行系统计算。分析对比,给出了同离子效应、酸液浓度、地层温度、反应生成热等因素对酸液有效作用距离影响的对比数据和图表。本文所编制的计算机程序和得到的结论可供酸压施工和设计计算使用。     

Modeling Benzene Pharmacokinetics Across Three Sets of Animal Data: Parametric Sensitivity and Risk Implications

Typically, the uncertainty affecting the parameters of physiologically based pharmacokinetic (PBPK) models is ignored because it is not currently practical to adjust their values using classical parameter estimation techniques. This issue of parametric variability in a physiological model of benzene pharmacokinetics is addressed in this paper. Monte Carlo simulations were used to study the effects on the model output arising from variability in its parameters. The output was classified into two categories, depending on whether the output of the model on a particular run was judged to be generally consistent with published experimental data. Statistical techniques were used to examine sensitivity and interaction in the parameter space. The model was evaluated against the data from three different experiments in order to test for the structural adequacy of the model and the consistency of the experimental results. The regions of the parameter space associated with various inhalation and gavage experiments are distinct, and the model as presently structured cannot adequately represent the outcomes of all experiments. Our results suggest that further effort is required to discern between the structural adequacy of the model and the consistency of the experimental results. The impact of our results on the risk assessment process for benzene is also examined.     

专题弁言：中国历史交通地理

灯塔对近代航运发展和航道安全而言具有举足轻重的意义。传统研究更多是从全国层面切入或以沿海地区为中心分析灯塔的发展变迁,并未对内河特别是长江流域的灯塔建设进程及其所面临的安全问题进行过专门讨论,忽视了内河流域相较于沿海地区在灯塔建设防护中的特殊性。利用灯塔表和相关报刊资料对长江中下游灯塔发展及其防护措施的变化进行分析发现,由于灯塔建设中资金不足、人员较少、防护措施简陋和配套制度不够完善,长江中下游的灯塔及其人员比沿海灯塔和灯塔职员更容易成为盗窃和抢劫犯罪的目标,这种风险的存在也影响到航运和航行人员的安全。     

初始信任对个人互联网理财使用意愿的影响研究--兼论性别、受教育水平等因素的中介效应与调节效应

互联网金融飞速发展,其中以余额宝为代表的货币基金类理财产品最为引人瞩目。以行为理论模型为框架,初始信任为研究出发点,引入性别、受教育水平、使用经验等调节变量构建了三阶段模型,基于301位互联网理财用户的有效调研数据,运用结构方程、线性回归等方法进行实证分析。结果表明:引入初始信任的行为理论整合模型能够更好地解释用户的互联网理财使用行为;初始信任是用户感知易用性和使用意愿间的显著性中介变量,中介效应比例为总效应的54.0%;性别与受教育水平在使用意愿的不同影响关系中起显著性的调节效应;使用经验在初始信任与使用意愿间的调节效应不显著,从动态角度来看,初始信任能够持续稳定地影响使用意愿。研究结论为互联网理财供给方提高产品竞争力、培育忠诚用户和市场规模的扩大提供了理论依据与决策支撑。     

National and ethnographic groups in Central Asia as reflected in ethnic statistics (Part 2)

This is the second part of an article in which the author examines trends in population growth and development among the national and ethnographic groups of the republics of Central Asia. The historical process of ethnic group consolidation is studied, with a focus on the roles of bilingualism, cross-national marriage, and socioeconomic development in inter-ethnic integration     

National and ethnographic groups in Central Asia as reflected in ethnic statistics (Part 1)

The author examines trends in population growth and development among the national and ethnographic groups of the republics in Central Asia. The historical processes of ethnic groups consolidation, population growth and distribution, and socioeconomic development are traced from the period of the Czarist empire to the present. Data are primarily from population censuses of the USSR     

Essay: On the place of the Holocaust in history. In honour of Franklin H. Littell

The Holocaust was a human event, perpetrated for human reasons which can be historically explained. As an event within history, it is unique in terms of the murderers'S motivation: a mission to rescue Germany, Europe and the world from their supreme enemy, the Jews. Other events, such as that which seems to most closely parallel the Holocaust, the Armenian massacres by the Turks in World War I, bear certain similarities to the Holocaust. Yet. In its attempt at total physical annihilation of all Jews everywhere, the Holocaust is unique. It stands at the extreme end of a continuum of human brutality, extending from mass murder, which has become commonplace, to genocide, and to Holocaust.     

Urbanization problems in China

Problems related to urbanization in China are discussed. The author first reviews trends in urbanization over the past 30 years, and then considers the relationship between urbanization and the country's economic growth. Probable future trends in urbanization up to the year 2000 are next described, with a final note on regional differences in urbanization patterns.     

Socio-economic and cultural differentials in contraceptive usage among Ghanaian women

Data from the Ghana Fertility Survey of 2001 married women in 1979-1980 were subjected to logistic regression to determine the factors influencing contraceptive use. In this Ghanaian sample only 22 women and no men were sterilized, 11% used an efficient contraceptive method and 8% were using an inefficient method. The most prevalent methods were abstinence by 6% and pill by 5%. The variables analyzed were birth cohort, age at 1st marriage, education, occupation, religion, ethnicity, rural/urban residence, northern/southern residence and number of children desired number of living children. All these factors were dichotomized, e.g., cohort: born before or after 1950. Factors positively significant for contraceptive use were younger women (20% more likely), married at age 20 or older (82% more), education (150% for any method, 67% for an efficient method), professional occupations, protestants, urban residence, southern residence, desire fewer children. Factors negatively associated with contraception were agricultural work (50% as likely), non-Christian religion, both traditional and Moslems (75%), desiring more children and living in the north. Unexpectedly, living in the northern undeveloped region was strongly linked with use of an efficient contraceptive. A factor without significant effect was ethnicity, Akan or non-Akan. These results were discussed with a general review of the literature on determinants of contraceptive use.