Correcting the Errors: Volatility Forecast Evaluation Using High‐Frequency Data and Realized Volatilities

We develop general model‐free adjustment procedures for the calculation of unbiased volatility loss functions based on practically feasible realized volatility benchmarks. The procedures, which exploit recent nonparametric asymptotic distributional results, are both easy‐to‐implement and highly accurate in empirically realistic situations. We also illustrate that properly accounting for the measurement errors in the volatility forecast evaluations reported in the existing literature can result in markedly higher estimates for the true degree of return volatility predictability.     

Academic and Behavioral Outcomes Among the Children of Young Mothers

In this article, we use newly available data from the National Longitudinal Survey of Youth to investigate the effects of early motherhood on academic and behavioral outcomes for children born to early child bearers. We find that early motherhood's strong negative correlation with children's test scores and positive correlation with children's grade repetition is almost entirely explained by prebirth individual and family background factors of teen mothers themselves. However, early childbearing is associated indirectly with reduced children's test scores through its linkage to family size (and thus to child birth order). We find a different pattern in predicting fighting, truancy, early sexual activity, and other problem behaviors among adolescent and young adult offspring. For these behaviors, maternal age at first birth remains an important risk factor even after controlling for a wide range of background factors and maternal characteristics. These results highlight the diverse pathways through which teen parenting might influence subsequent child well‐being and social performance.     

基于视听说网络的大学英语自主学习效果实证研究

国内外许多学者对自主学习进行了大量探讨与研究,但大部分都限于对自主学习能力的界定、对其理论依据和实施策略等进行阐述与分析,几乎没有相关的实证研究。基于此有必要运用实证研究,把学习者在自主学习中各个级别的测试成绩(包括听力、词汇、语法、拼写、口语五个方面)作为一因变量,分析大学生在视听说网络教学模式下自主学习的效果,以了解自主学习对大学英语教学的积极作用以及存在的问题。     

Improving Intimate Partner Violence Services in Home Visiting: A Multisite Learning Collaborative Approach

Abstract

To improve intimate partner violence (IPV) service delivery, the Florida Maternal, Infant, and Early Childhood Home Visiting (MIECHV) Initiative’s continuous quality improvement (CQI) team implemented a Breakthrough Series model Learning Collaborative with eight program sites. Using mixed-methods, we: examined post-Collaborative changes in Florida MIECHV home visitors’ knowledge, system awareness, and confidence; identified strategies to address challenges in supporting families with IPV; and assessed post-Collaborative program improvements. The Collaborative included three interactive 2-day sessions, six webinars, and testing strategies using the Model for Improvement (Plan-Do-Study-Act). Three online surveys assessed changes influencing IPV screening, referrals, and safety planning. Thematic content analysis of qualitative data revealed existing barriers and strategies to address challenges. Home visitors reported accurate knowledge (change: 2.3%-34.8%), confidence (change: 31.8%-37.9%), and system awareness (change: 22.7%-53.5%) for all items from baseline to final survey. There was also an increase in rates of IPV screening (change: 88.0%-91.0%) and referrals (change: 43.0%-100.0%). Strategies for addressing challenges in supporting families experiencing IPV were identified at the individual (self-care, continuous education); interpersonal (reflective supervision, trauma-informed approach); organizational (defining success, supportive agency/program, policies); and community (collaboration with IPV service providers) levels. Lessons learned from the MIECHV IPV Learning Collaborative informed future CQI projects.     

Obtaining cancer risk factor prevalence estimates in small areas: combining data from two surveys

Summary.  Cancer surveillance research requires accurate estimates of risk factors at the small area level. These risk factors are often obtained from surveys such as the National Health Interview Survey (NHIS) or the Behavioral Risk Factors Surveillance System (BRFSS). The NHIS is a nationally representative, face-to-face survey with a high response rate; however, it cannot produce state or substate estimates of risk factor prevalence because the sample sizes are too small and small area identifiers are unavailable to the public. The BRFSS is a state level telephone survey that excludes non-telephone households and has a lower response rate, but it does provide reasonable sample sizes in all states and many counties and has publicly available small area identifiers (counties). We propose a novel extension of dual-frame estimation using propensity scores that allows the complementary strengths of each survey to compensate for the weakness of the other. We apply this method to obtain 1999–2000 county level estimates of adult male smoking prevalence and mammogram usage rates among females who were 40 years old and older. We consider evidence that these NHIS-adjusted estimates reduce the effects of selection bias and non-telephone coverage in the BRFSS. Data from the Current Population Survey Tobacco Use Supplement are also used to evaluate the performance of this approach. A hybrid estimator that selects one of the two estimators on the basis of the mean-square error is also considered.     

连续贝塔、非连续贝塔与股票风险溢酬

本文利用高频数据将传统的CAPM贝塔分解为连续贝塔和非连续贝塔（跳跃贝塔和隔夜贝塔），并在此基础上进一步考虑正向市场和负向市场的非对称性，将跳跃贝塔又细分为正向跳跃贝塔和负向跳跃贝塔，以探讨不同类型系统性风险的特征差异及其所对应的风险溢酬。实证结果表明，个股对市场发生的非连续变动比连续变动更加敏感，投资者对市场发生的负向跳跃比正向跳跃反应更加强烈；中国股票市场上的系统性非连续风险溢酬（跳跃风险溢酬和隔夜风险溢酬）显著为正，但系统性连续风险并没有得到定价；其中，跳跃风险溢酬则主要来源于对系统性负向跳跃风险的补偿，而正向跳跃风险对股票横截面收益率没有显著的影响。     

Sildenafil versus continuous positive airway pressure for erectile dysfunction in men with obstructive sleep apnea: a meta-analysis

Objective.?To evaluate the effectiveness of sildenafil versus continuous positive airway pressure (CPAP) for patients with erectile dysfunction (ED) and obstructive sleep apnea (OSA).

Methods.?This is a meta-analysis of a randomized controlled trial. The main outcome measures for effectiveness were the percentage of successful intercourse attempts, International Index of Erectile Function (IIEF) domain scores (erectile function, EF) and the satisfaction levels of the patients and their partners with the treatment for ED.

Results.?Two randomized controlled trials totaling 70 patients were included. Meta-analysis results are as follows: after 12 weeks of treatment, patients under sildenafil demonstrated a significant advantage over under CPAP in terms of the percentage of successful intercourse attempts [OR?=?3.24, 95% CI (2.37–4.43)], EF scores [WMD?=?3.57, 95%CI (1.68–5.45)], and the satisfaction levels of the patients and their partners with the treatment for ED [OR?=?3.56, 95% CI (1.27–9.98)].

Conclusion.?Current clinical studies might confirm that both therapeutic methods were safe and effective, but sildenafil was superior to CPAP in the treatment of ED in men with OSA. We conclude that new therapeutic agents or a combination of the two methods should be studied further.     

Euler(p,q) Processes and Their Application to Non Stationary Time Series with Time Varying Frequencies

We introduce Euler(p, q) processes as an extension of the Euler(p) processes for purposes of obtaining more parsimonious models for non stationary processes whose periodic behavior changes approximately linearly in time. The discrete Euler(p, q) models are a class of multiplicative stationary (M-stationary) processes and basic properties are derived. The relationship between continuous and discrete mixed Euler processes is shown. Fundamental to the theory and application of Euler(p, q) processes is a dual relationship between discrete Euler(p, q) processes and ARMA processes, which is established. The usefulness of Euler(p, q) processes is examined by comparing spectral estimation with that obtained by existing methods using both simulated and real data.     

网络自主学习领域研究中的问题

大学英语的网络自主学习正在各个高校广泛开展，对于网络自主学习进行研究也是为了更好地促进学生自主学习的发展，但对该领域的研究存在一些问题，如论文的理论框架部分较少引用最新理论，某些实验研究中存在逻辑缺失之处，即不同实验组别之间没有同等的实验条件，这都会对研究得到正确结论产生不利影响。此外，在实验设计中一些研究过于注重比较学生的成绩等，而这些并不是国家推行网络自主学习的目的所在。网络自主学习的目的是为了促进学生自主学习能力的发展，从某种程度上说，自主学习本身就是目的，因此，不应该用成绩来苛求网络自主学习。衡量网络自主学习是否成功，用质的方法更为合适。     

如何用SPSS软件一步算出主成分得分值

主成分分析法常被应用于综合评价与监控,其评价与监控值就是样品的主成分得分值,故尽快求出主成分得分值是实现综合评价与监控的重要环节之一。多数人使用的SPSS软件求解主成分得分值的方法较慢,甚至出现错误。而从理论上给出主成分得分值与未旋转因子得分值的关系式,并利用SPSS软件因子分析模块中未旋转因子得分值,一步算出主成分得分值,则大大简化了计算,其效果比以前的方法好。同时也改正了一些新版文献的错误。