Influence diagnostics for the structural sharpe model under normal/independent distributions

A method is proposed in this paper to assess the local influence of minor perturbations for the Sharpe model when the normal distribution is replaced by normal/independent (NI) distributions. The family of NI distributions is an attractive class of symmetric heavy-tailed densities that includes as special cases the normal, t-Student, slash, and the contaminated normal distributions. Since the returns of the market are not observable, the statistical analysis is carried out in the context of an errors-in-variables model. An influence analysis for detecting influential observations (atypical returns) is developed to investigate the sensitivity of the maximum likelihood estimators. Diagnostic measures are obtained based on the conditional expectation of the complete-data log-likelihood function. The results are illustrated by using a set of shares of companies traded in the Chilean stock market.     

新常态下交通对中国经济质量增长的贡献

根据交通外部性和非线性理论构建交通门槛模型,并基于1985-2012年中国省际面板数据,采用Hansen门槛效应的内生分组方法检验新常态下交通对中国经济增长质量的贡献。结果显示：新常态下交通对经济增长质量贡献略低于"旧常态",但仍表现出区间"递增"趋势;把新常态下TFP分解为技术进步和技术效率,发现中密度地区要素配置结构已不适应技术进步的需要,高密度地区技术效率相对技术进步对经济增长质量的贡献较低;随着区间交通密度的增加,"政府干预经济"更有效率,但城市化和产业发展对经济增长质量贡献由正转负。为进一步提升新常态下交通对中国经济增长质量的贡献,应定向适度加大"中密度地区"交通投资力度,助其跳出"低增长陷阱";借助信息化、智能化手段引领交通建设转型升级以提高经济运行效率;构建"交通-产业-城镇"三位一体的协同新型综合交通体系;协调好城市化与交通基础设施建设之间的关系。     

轻重学说在汉武帝时的实践和发展——兼论耿寿昌的常平仓制度

轻重学说旨在增收国家财政,这一性质使其成为封建政府解决财政危机的重要工具。西汉武帝政府面对＂县官空虚＂的财政状况,不仅把＂立币,国铜＂、＂官山海＂、＂敛之以轻,散之以重＂等轻重理论运用于增收国家财政的实践,还在实践中发展了这种学说。轻重学说在宣帝时耿寿昌的常平仓制度中亦有体现。     

Fathers' birth experience in relation to midwifery care

The aim was to identify the proportion of fathers having a positive experience of a normal birth and to explore factors related to midwifery care that were associated with a positive experience.

Background

Research has mainly focused on the father's supportive role during childbirth rather than his personal experiences of birth.

Methods

595 new fathers living in a northern part of Sweden, whose partner had a normal birth, were included in the study. Data was collected by questionnaires. Odds Ratios with 95% confidence interval and logistic regression analysis were used.

Results

The majority of fathers (82%) reported a positive birth experience. The strongest factors associated with a positive birth experience were midwife support (OR 4.0; 95 CI 2.0–8.1), the midwife's ongoing presence in the delivery room (OR 2.0; 1.1–3.9), and information about the progress of labour (OR 3.1; 1.6–5.8).

Conclusion

Most fathers had a positive birth experience. Midwifery support, the midwife's presence and sufficient information about the progress of labour are important aspects in a father's positive birth experience. The role of the midwife during birth is important to the father, and his individual needs should be considered in order to enhance a positive birth experience.     

国际法视野下碳排放权的法律属性

目前,国内法学研究将碳排放权的法律属性界定为环境财产权、新型财产权、用益物权、准物权等。站在国内法的角度,这些对碳排放权的法理解释有其合理性。但从“差别原则”向“共同原则”转变的进程中,更需要从国际法层面对碳排放权的法律属性作出深层次的回应。碳排放权的自然法、国际人权法以及人类生态法属性应是当代人类控制温室气体,确保人类享有清洁空气权的国际法理论解释。     

The Volatility of Realized Volatility

In recent years, with the availability of high-frequency financial market data modeling realized volatility has become a new and innovative research direction. The construction of “observable” or realized volatility series from intra-day transaction data and the use of standard time-series techniques has lead to promising strategies for modeling and predicting (daily) volatility. In this article, we show that the residuals of commonly used time-series models for realized volatility and logarithmic realized variance exhibit non-Gaussianity and volatility clustering. We propose extensions to explicitly account for these properties and assess their relevance for modeling and forecasting realized volatility. In an empirical application for S&P 500 index futures we show that allowing for time-varying volatility of realized volatility and logarithmic realized variance substantially improves the fit as well as predictive performance. Furthermore, the distributional assumption for residuals plays a crucial role in density forecasting.     

Single-stage sampling procedure of the t best populations under heteroscedasticity

Given k( ? 3) independent normal populations with unknown means and unknown and unequal variances, a single-stage sampling procedure to select the best t out of k populations is proposed and the procedure is completely independent of the unknown means and the unknown variances. For various combinations of k and probability requirement, tables of procedure parameters are provided for practitioners.     

教育变迁视野下人口较少民族文化传承路径及其困境——以云南布朗族为例

全球化浪潮使得布朗族如其他绝大多数少数民族一样正面临外来文化冲击,如何有效传承本民族传统文化日益重要。本研究认为,教育是人类文化传承的重要途径;随着社会的发展,布朗族传统教育的模式及其功能发生了改变;民族地区现代学校教育责无旁贷地成为当今民族文化传承的重要场所,尽管它正面临传承与发展的两难困境。     

高校汉语言文学专业师范生实践教学存在问题与对策

高校汉语言文学专业师范生实践教学在教学技能培养方面取得了一定成效,但就教育改革发展的要求来看,现阶段还存在亟待解决的问题：实践教学效果两极分化;实践教学过程程序化、形式化;教学方式缺乏特点和亮点;教学资源不足;教学评价机制落后等。问题的根源在于：思想上重视不足;理论与实践脱节;缺乏针对性;缺少时间的保证和一线教学经历。问题的解决途径主要有：加强重视程度;坚持实践教学的灵活性;实践教学常态化;加强教学针对性,评价标准科学化。     

Moment-Implied Densities: Properties and Applications

Suppose one uses a parametric density function based on the first four (conditional) moments to model risk. There are quite a few densities to choose from and depending on which is selected, one implicitly assumes very different tail behavior and very different feasible skewness/kurtosis combinations. Surprisingly, there is no systematic analysis of the tradeoff one faces. It is the purpose of the article to address this. We focus on the tail behavior and the range of skewness and kurtosis as these are key for common applications such as risk management.