一类函数积分的估值公式与近似计算

用一种简捷的方法,讨论了一类满足一定条件的多元函数在任意区域上的积分问题,将任意积分区域简化为常见区域的积分,并给出了估值公式,举例说明了在积分近似计算中的应用及误差分析,同时进行了有关的数值分析,从而更直观地展示了估值公式的意义。     

利用函数的凸凹性证明均值不等式

从利用Jensen不等式证明均值不等式关系的过程中函数的取法入手 ,证明了这种不等关系与函数性质 (凸性、单调性 )之间的关系 ,由此可以定义一种更一般的平均———函数平均 ,而调和平均、几何平均、算术平均只是函数平均在特殊函数上的表现     

A Room With a View or a Room of One's Own? Housing and Social Stratification

This study attempts to understand the role that housing plays in the system of social stratification. First, it generates a model of how housing outcomes are stratified along dimensions of socioeconomic status and race. Second, it asks what role housing conditions play in the system of educational stratification of offspring. Using two-generational data from the Panel Study of Income Dynamics, this paper demonstrates that home ownership is predicted by family income and race and that this indicator has a significant effect in predicting the educational attainment of offspring. Household crowding is also related to income and race and also affects the educational attainment of offspring. Meanwhile, housing quality—as measured by the physical condition of the unit—is not related to income or race and has no effect on educational attainment. Of particular note is that when socioeconomic status and housing conditions are held constant, African-Americans demonstrate more than a half-grade advantage over their non-black counterparts in years of completed schooling. In conclusion, the paper argues that housing matters not only for the immediate well-being of families, but also for the life-chances of the subsequent generation, and should be a standard variable in the conception of class background.     

Examining racial differences in the effect of popular sports participation on academic achievement

Using data from the Education Longitudinal Study of 2002, this study employs propensity score modeling to measure the effects of participation in varsity football (among men) and varsity basketball (among men and women) in the 10th grade on students’ GPAs and math test scores in the twelfth grade. This study also investigates whether the effect of sports participation on student achievement differs between black and white students. The results show that participation in varsity football negatively affects the 12th grade GPAs of black, but not white, men but does not affect the math test scores of either of these subgroups. Moreover, varsity basketball participation leads to higher GPAs in the 12th grade among white, but not black, women. Implications of the different operationalizations of sports participation, the investigation of different student subpopulations, and the different methods of analysis are discussed.     

变时滞控制系統的镇定性

本文首先建立一个变系数变时滞微分不等式。然后,利用此微分分等式研究具有变量时滞的控制系统的镇定问题,获得了判别系统镇定的简便充不了,准则。     

收入不平等与经济发展——基于中国省际面板数据的分析

基于1987-2005年的中国省级面板数据对收入不平等与经济发展之间的关系进行了分析.有证据表明中国确实存在着不平等程度随经济发展先提高后降低的现象(也即不平等与经济发展水平存在Kuznets倒U型关系),转折点大约在人均GDP达到15 870元(1987年价格水平)时出现.文章随后分析了收入不平等对经济发展的影响,结果发现本期的经济增长速度随着上期收入不平等水平的提高呈现先升后降的趋势.在收入不平等的变化对经济增长的影响方面没有发现一致的结论.     

具有网络外部性的扩展Hotelling模型

将网络外部性引入线性运输成本下的Hotelling模型,研究了两家网络产品厂商首先选址,然后进行价格竞争的两阶段完全信息动态博弈问题,得到了厂商价格竞争均衡的存在性条件,推广了一般Hotelling模型的结论.由于网络外部性的存在,消费者效用是相互依赖的.网络产品的市场份额既是消费者选择的结果,又是消费者选择的依据.文章将交通流量分配技术和无穷维变分方法相结合,建立了刻画网络产品市场划分的模型——无穷维变分不等式,并研究了市场划分的存在性和唯一性问题.最后假定厂商定位在两端,分析了产品的网络外部性特征及单位运输成本对两个厂商竞争均衡情况的影响.     

Gender inequality in mobile technology access: the role of economic and social development*

ABSTRACT

Digital inequality is a burgeoning field of study across disciplines, yet few papers address categorical digital inequality in cross-national samples. Using the only available cross-national data on access to Information and Communications Technologies (ICTs) disaggregated by gender from the International Telecommunications Union (ITU), I add to existing literature by examining factors associated with women’s unequal access to mobile phones across 51 countries. The largest of such samples, the ITU data demonstrates that the type and levels of gender inequality in mobile phone use are not consistent throughout countries. In fact, the distribution is quite variable, from incorporating a small-sample of nations where women have marginally higher access, to sub-samples close to parity, to a larger sub-sample where women are at a substantial disadvantage. Using Quantile Regression Methods to assess these variations, I test how major gender and international development theories inform inequality patterns. My findings suggest that women’s wellbeing, as measured by their access to modern contraception (i.e., reproductive autonomy), overwhelmingly promotes women’s relative access to mobile phones, regardless of preexisting levels of access. Other perspectives like the growth imperative and world polity theory show some staggered associations along the distribution that remain substantively inconclusive.     

Rising powers,people rising: neo-liberalization and its discontents in the BRICS countries

ABSTRACT

The rise of the BRICS countries – Brazil, Russia, China, India, and South Africa – has called into question the future of Western dominance in world markets and geopolitics. However, the developmental trajectories of the BRICS countries are shot through with socio-economic fault lines that relegate large numbers of people to the margins of current growth processes, where life is characterized by multiple and overlapping vulnerabilities. These socio-economic fault lines have, in turn, given rise to political convulsions across the BRICS countries, ranging from single-issue protests to sustained social movements oriented towards structural transformation. This article presents an innovative theoretical framework for theorizing the emerging political economy of development in the BRICS countries centred on neo-liberalization, precarity, and popular struggles. It discusses the contributions to this special issue in terms of how they illuminate the intersection between neo-liberalization, precarity, and popular struggle in Brazil, Russia, India, China, and South Africa.