Trends in long-acting reversible contraceptive (LARC) use,LARC use predictors,and dual-method use among a national sample of college women

Objective: Assess long-acting reversible contraceptive (LARC) and other contraceptive use trends, identify LARC use predictors, and examine dual method use. Participants: Women in the American College Health Association-National College Health Assessment (ACHA-NCHA) II, aged 18–24 years, who reported having vaginal sex (N = 37,899). Methods: Secondary analyses of Fall 2011–2014 ACHA-NCHA II data. Results: Statistically significant increases in LARC usage and, specifically, implant usage, were found. Characteristics associated with LARC use included age, race/ethnicity, relationship status, and school type. Students reporting LARC use had lower odds of condom usage compared with non-LARC hormonal method users. Conclusion: This analysis of LARC predictors and dual LARC/condom use has implications for research and health promotion efforts. Findings suggest that college health services are well positioned to meet the sexual and reproductive health needs of diverse populations of students. College health professionals should elicit students' individual and/or relationship priorities to tailor messaging/services offered for pregnancy/STI prevention.     

Investigating the Relationship Between Real Estate Agents,Segregation, and House Prices: Steering and Upselling in New York State

This article leverages a unique data set, recently developed regression methods, and qualitative interviews to investigate the multiple ways real estate agents produce housing inequality. We find that the clustering of agents in and around certain neighborhoods correlates positively with house prices. Our results also show a significant relationship between agent concentration and racial segregation. Our qualitative data reveal how agents engage in steering and upselling. The findings enhance our understanding of mechanisms in the housing market, and provide more empirical clarity on the role real estate agents play in asset and place inequality.     

ANOVA models for Brownian motion

We investigate longitudinal models having Brownian-motion covariance structure. We show that any such model can be viewed as arising from a related “timeless” classical linear model where sample sizes correspond to longitudinal observation times. This relationship is of practical impact when there are closed-form ANOVA tables for the related classical model. Such tables can be directly transformed into the analogous tables for the original longitudinal model. We in particular provide complete results for one-way fixed and random effects ANOVA on the drift parameter in Brownian motion, and illustrate its use in estimating heterogeneity in tumor growth rates.     

Statistical considerations for assessing precision of heterogeneous duplicate measurements: An application to pharmaceutical bioanalysis

Duplicate analysis is a strategy commonly used to assess precision of bioanalytical methods. In some cases, duplicate analysis may rely on pooling data generated across organizations. Despite being generated under comparable conditions, organizations may produce duplicate measurements with different precision. Thus, these pooled data consist of a heterogeneous collection of duplicate measurements. Precision estimates are often expressed as relative difference indexes (RDI), such as relative percentage difference (RPD). Empirical evidence indicates that the frequency distribution of RDI values from heterogeneous data exhibits sharper peaks and heavier tails than normal distributions. Therefore, traditional normal-based models may yield faulty or unreliable estimates of precision from heterogeneous duplicate data. In this paper, we survey application of the mixture models that satisfactorily represent the distribution of RDI values from heterogeneous duplicate data. A simulation study was conducted to compare the performance of the different models in providing reliable estimates and inferences of percentile calculated from RDI values. These models are readily accessible to practitioners for study implementation through the use of modern statistical software. The utility of mixture models are explained in detail using a numerical example.     

双重异质信念下中国上市公司融资决策研究

投资者异质信念与投资者-管理者异质信念是我国资本市场的重要特征。本文在双重异质信念假设下,基于我国上市公司融资环境,建立融资决策模型,分析双重异质信念对我国上市公司股权债权融资选择的影响,得到结论:(1)卖空限制下,投资者异质信念越大,公司越倾向于股权融资;(2)投资者-管理者异质信念越小,公司越倾向于股权融资。以2005-2009年沪深A股再融资公司为样本,采用单变量分析和Probit多元回归方法,对模型结论进行实证检验,实证结果支持模型结论,并从双重异质信念的视角对我国资本市场融资异象进行解释。     

投入产出视角下工业技术创新的环境规制协同效应

技术创新是实现经济发展和环境保护"双重红利"的必要途径。为此,构建环境规制影响工业技术创新投入产出的三阶段分析框架,利用中国2002-2015年大中型工业企业35个分行业面板数据,使用动态面板系统广义矩估计（GMM）方法,在区分行业间污染排放强度波动趋势异质性的条件下实证检验环境规制对工业技术创新投入、产出的非线性影响及分阶段作用机制,找寻工业技术创新的环境规制最优协同区间,进一步引入交互项模型分析环境规制、创新投入、创新产出之间的交互影响与协同效应,以综合探究工业技术创新的环境规制协同机制。研究结果表明:（1）除在污染排放强度为递增样本,环境规制与创新人员、资金投入均呈现"U形"关系;（2）环境规制与创新知识、产品产出均呈现"倒U形"关系;（3）虽然在全样本中存在创新投入产出分阶段协同作用的最优环境规制区间,但中国现阶段环境规制水平还处于各曲线拐点左侧,远低于协同区间水平;（4）在创新技术研发阶段,存在环境规制与创新资金投入的协同效应,在创新技术转化阶段,存在环境规制与创新知识产出的协同效应。目前,中国工业行业整体环境规制水平仍然较低,为实现环境与经济的双赢,应提高环境规制强度,针对不同工业行业制定环境规制滚动修正、动态调整机制,充分发挥环境规制对工业行业技术创新的推动作用。     

存在爽约行为的异质患者序列预约调度优化

针对服务时间不同且存在爽约行为的异质患者,考虑患者的动态预约过程,设计患者的序列调度优化方案。给定患者集合,以最小化患者等待时间成本和医生空闲及加班成本为目标,建立混合整数规划模型,分别在不考虑患者超订和允许患者超订两种情况下优化排序方案。在此基础上,设计患者动态到达的序列预约调度优化方案,在患者发出预约请求时立即决定是否接受该患者,同时为接受预约的患者安排相应的服务时间,即为其分配服务开始时间。进一步地,提出将服务时间差异较大的患者进行分类调度、分时段就诊的预约方案,以减少医生加班和空闲时间。通过数值计算验证模型和算法的有效性。此外,数值结果显示,基于患者服务时间差异进行分类分时段的调度方案可以在一定程度上降低系统成本,提高服务效率。     

苏州市国际货运代理业的现状与发展

苏州发展货运代理业有着巨大的潜力.我们应完善货代业的管理法规,加强国际货代市场的监管力度;货代企业也要树立品牌意识,提高服务质量,实现规模经营,走联合之路.     

Testing for Equivalence of Means under Heteroskedasticity by an Approximate Solution of a Partial Differential Equation of Infinite Order

Abstract. A test for two‐sided equivalence of means has been developed under the assumption of normally distributed populations with heterogeneous variances. Its rejection region is limited by functions ± h that depend on the empirical variances. h is stated implicitly by a partial differential equation, an exact solution of which would provide a test that is exactly similar at the boundary of the null hypothesis of non‐equivalence. h is approximated by Taylor series up to third powers in the reciprocal number of degrees of freedom. This suffices to obtain error probabilities of the first kind that are very close to a nominal level of α = 0 . 05 at the boundary of the null hypothesis. For more than 10 data points in each group, they range between 0.04995 and 0.05005, and are thus much more precise than those obtained by other authors.     

Fairness Among Servers When Capacity Decisions Are Endogenous

We look at a simple service system with two servers serving arriving jobs (single class). Our interest is in examining the effect of routing policies on servers when they care about fairness among themselves, and when they can endogenously choose capacities in response to the routing policy. Therefore, we study the two‐server game where the servers’ objective functions have a term explicitly modeling fairness. Moreover, we focus on four commonly seen policies that are from one general class. Theoretical results concerning the existence and uniqueness of the Nash equilibrium are proved for some policies. Further managerial insights are given based on simulation studies on servers’ equilibrium/off‐equilibrium behaviors and the resulting system efficiency performance under different policies.