Changing compatibility of cohabitation and childbearing between young British women born in 1958 and 1970

We investigate the effect of parenthood on whether non-marital unions led to marriage or parting for two cohorts of British women when they were aged between 16 and 29. We compare the effect of conceptions leading to births and the presence and characteristics of children on the odds that a cohabitation was dissolved, or that it was converted to marriage, for women born in 1958 and 1970. A multilevel, multiprocess, competing-risks model allows for multiple cohabitations per woman and endogeneity of fertility status. We find that cohabiting couples’ response to impending parenthood and the presence of children changed over time. In particular, the proportion of cohabiting couples who married before a birth decreased and, in the 1970 cohort only, the risk of dissolution declined during pregnancy. There is also evidence that the presence of a child cemented a cohabiting union for women from the 1970, but not the earlier, cohort.     

Host-feeding and oviposition strategies of parasitoids in relation to host stage

Summary Until now, mathematical models of parasitoid-host interactions have not incorporated the tendency for destructively host-feeding parasitoids to partition their feeding and oviposition behaviour in relation to different host stages. A literature survey reveals a trend for female parasitoids to feed preferentially or exclusively on earlier host stages and to oviposit preferentially or exclusively in/or later ones. We explore the relative advantages to host-feeding parasitoids of a number of possible host stage selection strategies. We develop hypotheses, formalizing and testing them using modifications to our earlier simulation model of host-feeding strategies (Jervis and Kidd, 1986). We conclude from our modelling that the advantage to be gained from feeding on early host stages and ovipositing in late ones is likely to be associated with: 1) reduced handling times when feeding on early stage hosts; 2) reduced wastage of progeny from mortality factors other than host-feeding by the parent parasitoid, achieved by confining oviposition to late host stages; and 3) reduced probability of progeny mortality resulting from the parent's host-feeding activities.     

产业振兴生产效率经济影响研究

 本研究构建了一个动态可计算一般均衡模型（CGE）以量化估算中国产业振兴中的生产率变化之经济影响。主要结论：各产业的TFP的长期增长能促进国内生产总值的增长,所带来的增长效应都很高。振兴规划中的机电、电力、物流、化学、交通运输产业的TFP增长的乘数效应很大。技术进步对产业振兴规划中资本密集型产业的物质要素资本投入替代作用明显。走依靠技术进步的创新发展之路,才能科学有效地实施产业振兴规划,推进“两型社会”的建设和低炭经济发展。     

Sample‐size calculations for multi‐group comparison in population pharmacokinetic experiments

This paper describes an approach for calculating sample size for population pharmacokinetic experiments that involve hypothesis testing based on multi‐group comparison detecting the difference in parameters between groups under mixed‐effects modelling. This approach extends what has been described for generalized linear models and nonlinear population pharmacokinetic models that involve only binary covariates to more complex nonlinear population pharmacokinetic models. The structural nonlinear model is linearized around the random effects to obtain the marginal model and the hypothesis testing involving model parameters is based on Wald's test. This approach provides an efficient and fast method for calculating sample size for hypothesis testing in population pharmacokinetic models. The approach can also handle different design problems such as unequal allocation of subjects to groups and unbalanced sampling times between and within groups. The results obtained following application to a one compartment intravenous bolus dose model that involved three different hypotheses under different scenarios showed good agreement between the power obtained from NONMEM simulations and nominal power. Copyright © 2009 John Wiley & Sons, Ltd.     

论传统图形符号的艺术内涵

具有代表性的中国传统图形,如凤纹、云纹、鱼纹、涡纹等,都可从中探寻到其表现形式在各个历史时期发展演变的脉络。这种“形”的延伸是对原始母题的继承与延续,也是对其外在形式的衍生与拓展。高度现代化、信息化的社会,新材料、新技术的不断更新,新思想、新观念、以及国外的各种艺术思潮的涌入给中国的传统艺术带来了前所未有的冲击。     

气水交替驱油藏注入能力分析及优化

针对注入能力降低是制约气水交替驱提高油藏采收率的关键因素的问题,以相似理论中的检验分析法推导了气水交替注入无因次注入能力方程,运用考虑相渗和毛管滞后效应耦合的数值模拟方法,评价无因次注入能力的因素影响,讨论并优化了注入水气比。研究结果表明：对于特定油藏体系,通过增加注入气的富化度提高粘滞力重力比来达到改善驱替效果的方法比片面地增加注气速度更高一些;水气比越高,达到相同开采效果所需气量越小,但因此而出现较明显的注入能力下降的趋势。对于低粘滞力重力比的注气条件,选择水气比为2最佳;而对于高粘滞力重力比,则水气比为1是最佳选择。建议在水气比的优选时充分结合油藏地质特征和注入流体特性进行分析。     

CAFTA、ACFTA自贸区与WTO贸易自由化的比较研究

全球贸易自由化是一个艰难的过程,区域性自由贸易区的建设是通向全球贸易自由化的必经之路吗？本文采用CGE全球模型---GTAP来研究CAFTA、ACFTA自由贸易区与WTO多边贸易自由化之间的相互关系。就粮食作物而言的部门调整,一个可能的全面的中国-奥大利亚自由贸易区（CAFTA）与多边贸易自由化进程的目标是一致的（WTO多边自由化过程）,然而中国-东盟自由贸易区（CAFTA）却与多边自由化进程不一致。     

极端气候冲击下中国粮食安全的技术进步路径选择——基于动态CGE模型的模拟

基于中国动态可计算一般均衡（CGE）模型,系统探讨了极端气候冲击下中国粮食安全的最优技术进步路径选择。从产量、价格、进口依赖度以及人均占有量的视角综合考察了粮食安全指标的动态变化,结论表明：土地、劳动力和资本增进型技术进步会缓解极端气候对粮食安全的不利冲击,并且缓解的效果依次递减;土地和劳动增进型技术进步组合、土地和资本增进型技术进步组合、劳动力和资本增进型技术进步组合缓解极端气候对粮食安全冲击的效果也依次递减。提出：在当前小规模经营农户为主的条件下,为了缓解极端气候事件对粮食安全的不利冲击,粮食生产应重点鼓励土地增进型技术进步,其次是劳动力增进型技术进步。     

开放校内外实习基地实现人才培养模式创新

开放式实习实现了学生实习与企业相结合,实习与就业相结合,实习与教师科研相结合。河南工业大学在开放式实习教学方面进行了探索性研究和实践,积累了一定经验。     

国债市场利率期限结构波动的对偶变换建模

本文针对传统利率期限结构拟合曲线存在过度波动问题,构建定价误差绝对距离和波动曲率双重最优化模型,借助对偶几何程序转换为在线性约束区域内的绝对距离最小化问题,并运用负指数平滑立方L1样条和计算几何逼近算法求解模型参数,通过负指数立方L1样条、NSS模型和B样条进行样本内拟合与样本外预测能力的比较,证实负指数立方L1平滑样条对利率期限结构波动的定价精确度、结构性拟合和样本外预测能力均有明显的优势,丰富了国债市场利率期限结构波动与定价的理论基础和研究方法。