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。      

Testing Hypotheses in Nonparametric Models of Production

Data envelopment analysis (DEA) and free disposal hull (FDH) estimators are widely used to estimate efficiency of production. Practitioners use DEA estimators far more frequently than FDH estimators, implicitly assuming that production sets are convex. Moreover, use of the constant returns to scale (CRS) version of the DEA estimator requires an assumption of CRS. Although bootstrap methods have been developed for making inference about the efficiencies of individual units, until now no methods exist for making consistent inference about differences in mean efficiency across groups of producers or for testing hypotheses about model structure such as returns to scale or convexity of the production set. We use central limit theorem results from our previous work to develop additional theoretical results permitting consistent tests of model structure and provide Monte Carlo evidence on the performance of the tests in terms of size and power. In addition, the variable returns to scale version of the DEA estimator is proved to attain the faster convergence rate of the CRS-DEA estimator under CRS. Using a sample of U.S. commercial banks, we test and reject convexity of the production set, calling into question results from numerous banking studies that have imposed convexity assumptions. Supplementary materials for this article are available online.     

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.     

生态批评作为文学活动对于人的诗意生存

生态存在必然诗意地寻归生命有机性的运演节律。对人来说,或者对人的生存来说,生态对文学、文学对生态,都依生态存在而动,都是人的生命活动状态使然。生命有机性既是人的自然之身及感性生命的基础,又有机呈现人的多重存在关系,更需要精神性及审美化的提升,文学则是其中重要提升力量。生命、人与文学的生成及效应则依循诗意的节律,既形成整体的有效性,又显示着各方的魅力。当生态批评作为一种文学现象出现,从发生之初到广泛影响实际都在极大地关注着人的生存问题,并探寻人何以能诗意生存。当生态批评作为文学活动在助力,必然要成就那种“有效”及“魅力”,其方法、策略及目的性追寻,旨在助推人的活动不断地融入诗意生存。事实上,生态批评的阐释、评论、理性确证及学理基质,就是通过生态整体及诗意性的综合性体验,把控生态、生命、人与文学间的诗意关系,彰显其相互促动、相互映衬的魅力。     

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.