族群认同的血缘性重建--以海村京族人为例

本文对1949年以来海村京族人族群意识的变化进行了考察。认为,客观文化特征的不断消退,族际交流与族群互动的日益频繁,族群认同上功利性取向的不断增加以及“法定”的民族属性对京族认同的冲击,使海村京族人的族群认同面临表述上的危机。为了应对这种危机,海村京族人不得不重新利用血缘关系的不可替代性来重新构建其族群认同,并以此为基础复兴京族传统文化,强化族群成员的族群意识。     

Entry and Exit in OTC Derivatives Markets

We develop a parsimonious model to study the equilibrium and socially optimal decisions of banks to enter, trade in, and possibly exit, an OTC market. Although we endow all banks with the same trading technology, banks' optimal entry and trading decisions endogenously lead to a realistic market structure composed of dealers and customers with distinct trading patterns. We decompose banks' entry incentives into incentives to hedge risk and incentives to make intermediation profits. We show that dealer banks enter more than is socially optimal. In the face of large negative shocks, they may also exit more than is socially optimal when markets are not perfectly resilient.     

Estimation of Nonparametric Models With Simultaneity

We introduce methods for estimating nonparametric, nonadditive models with simultaneity. The methods are developed by directly connecting the elements of the structural system to be estimated with features of the density of the observable variables, such as ratios of derivatives or averages of products of derivatives of this density. The estimators are therefore easily computed functionals of a nonparametric estimator of the density of the observable variables. We consider in detail a model where to each structural equation there corresponds an exclusive regressor and a model with one equation of interest and one instrument that is included in a second equation. For both models, we provide new characterizations of observational equivalence on a set, in terms of the density of the observable variables and derivatives of the structural functions. Based on those characterizations, we develop two estimation methods. In the first method, the estimators of the structural derivatives are calculated by a simple matrix inversion and matrix multiplication, analogous to a standard least squares estimator, but with the elements of the matrices being averages of products of derivatives of nonparametric density estimators. In the second method, the estimators of the structural derivatives are calculated in two steps. In a first step, values of the instrument are found at which the density of the observable variables satisfies some properties. In the second step, the estimators are calculated directly from the values of derivatives of the density of the observable variables evaluated at the found values of the instrument. We show that both pointwise estimators are consistent and asymptotically normal.     

Relationships among JIT practices: an interpretive modeling approach

Abstract

This research develops a model of relationships among components of Total-JIT, including JIT-information, JIT-manufacturing, JIT-purchasing, and JIT-selling, to establish an implementation hierarchy based on relative importance. The data collected relates to the relationships among JIT components and two performance measures, supply chain competency and organizational performance. Two groups are used in the research, one group of five operations management academics and another group of 30 practicing operations managers working in U.S. manufacturing firms. An interpretive structural modelling methodology is used to develop alternative structural models. The academics’ data show JIT-information emerging as lynchpin of relationships, directly impacting all other JIT practices and both performance measures. The practitioners’ data indicates that all JIT practices and performance measures are interactive as components and outcomes. This study is the first to apply interpretive structural modelling to investigate the interplay among total-JIT components and the performance measures of supply chain competency and organizational performance.     

贫困地区新生代女性农民工休闲生活现状调查研究--以甘肃省定西市为例

休闲已成为现代人生活、工作所不可或缺的组成部分。作为经济转型时期的特殊社会群体,新生代女性农民工的休闲生活现状值得关注。研究以甘肃省定西市为例,从休闲时间、休闲消费、休闲认知三个维度对本地区新生代女性农民工与男性农民工、同龄城市女青年休闲生活进行对比研究,得出结论:贫困地区新生代女性农民工休闲时间严重不足,主要休闲消费方式仍处于消极型的休闲层次类型;相对于上一代农民工而言,她们已经认识到休闲的重要性,但由于受封闭的休闲空间及拮据的经济条件所限,她们的休闲动机仍停留在马斯洛的五个需求层次中前两层的初级需要。针对此现状,文章提出了相应的对策与建议。      

An F-type test for detecting departure from monotonicity in a functional linear model

When studying associations between a functional covariate and scalar response using a functional linear model (FLM), scientific knowledge may indicate possible monotonicity of the unknown parameter curve. In this context, we propose an F-type test of monotonicity, based on a full versus reduced nested model structure, where the reduced model with monotonically constrained parameter curve is nested within an unconstrained FLM. For estimation under the unconstrained FLM, we consider two approaches: penalised least-squares and linear mixed model effects estimation. We use a smooth then monotonise approach to estimate the reduced model, within the null space of monotone parameter curves. A bootstrap procedure is used to simulate the null distribution of the test statistic. We present a simulation study of the power of the proposed test, and illustrate the test using data from a head and neck cancer study.     

Male bisexuality and condom use at last sexual encounter: results from a national survey

Relatively little is known about condom use among bisexual men as separate and distinct from exclusively homosexual and heterosexual men. Most previous research on bisexual men has relied on non-probabilistic, high risk samples with limited generalizability. We examined the relationship between male behavioral bisexuality and condom use in the 2002 cycle of the National Survey of Family Growth (NSFG). Bisexually-active men positively differed from heterosexually- and homosexually-active men on every indicator of confounding risk. However, bisexually-active men did not report using condoms less often than other men during their last sexual encounters with males and females. Indeed, with female partners, bisexually-active men reported higher rates of condom use than other men. These relationships remained when all sociodemographic and confounding risk factors were held constant. Our results suggest that caution must be used when making assumptions about condom use in the general population of bisexual men from non-probabilistic samples.     

Association of sexual abstinence in adolescence with mental health in adulthood

We examined whether adolescent sexual abstinence predicts better adult mental health. 1,917 adolescents, recruited from middle schools at age 13, were surveyed at ages 13, 18, 23, and 29. In bivariate analyses, adolescent sexual abstinence was associated with better mental health at age 29 for females, but not males; three adolescent factors, educational prospects, family bonding, and unconventionality were investigated as explanatory variables of this relationship. The abstinence-mental health relationship was nonsignificant when educational prospects was included in multivariate models, and marginally significant when family bonding and unconventionality were included; all three explanatory factors accounted for significant proportions of the variance in adult mental health. Girls who are uninvolved in school, have weak family backgrounds, and exhibit unconventionality may have poor adult mental health, whether or not they abstain from sex in adolescence. Interventions that strengthen adolescents' connections to families and schools may reduce risk for long-term mental health problems.