Bootstrap methods for bias correction and confidence interval estimation for nonlinear quantile regression of longitudinal data

This paper examines the use of bootstrapping for bias correction and calculation of confidence intervals (CIs) for a weighted nonlinear quantile regression estimator adjusted to the case of longitudinal data. Different weights and types of CIs are used and compared by computer simulation using a logistic growth function and error terms following an AR(1) model. The results indicate that bias correction reduces the bias of a point estimator but fails for CI calculations. A bootstrap percentile method and a normal approximation method perform well for two weights when used without bias correction. Taking both coverage and lengths of CIs into consideration, a non-bias-corrected percentile method with an unweighted estimator performs best.     

试析林纾在《黑奴吁天录》中的变译

在《黑奴吁天录》中采用变译法主要由译者和读者两个因素决定,林纾通过采用阐译、缩译和改译三种变译,保持了译文信息的忠实、美学的忠实、语用功能的忠实和效果的忠实.变译的运用使译文创造性地忠实于原文,实现了忠诚原则与跨文化信息的有效传递.     

The boomerang effect of psychological interventions

Research has found that teaching people about psychological biases can help counteract biased behavior. On the other hand, due to the innate need for preservation of a positive self-image, it is likely that teaching people about biases they hold, may cause a boomerang effect in cases where being associated with a specific bias implies negative social connotations. In the three studies below we examine situations in which psychological bias implies negatively associated behavior, and show that teaching people about bias in those contexts can be counterproductive.     

Spatial Distribution of Flood Risk and Quality of Spatial Management: Case Study in Odra Valley,Poland

This article presents methodological solutions aimed at presenting the spatial distribution of flood risk and quality of spatial management (land use), indicating both those areas used reasonably and those requiring modification. The purpose was to identify key risk areas and risk‐free areas from the point of view of human security and activity on the floodplains, based on the examples of the vicinities of Wroclaw and Raciborz in the Odra Valley, Poland. Due to recent climate change, Poland has suffered the effects of severe flooding (e.g., 1997, 2001, 2010). The analyses conducted were motivated by the European Parliament and Council's recently implemented Directive 2007/60/WE, as well as by the demand for studies for local spatial planning. The analysis indicates that reasonably developed areas do not account for the majority of those studied, making up 36% of the Wroclaw area and 15% of the Raciborz area.     

Pricing arithmetic Asian option under a two-factor stochastic volatility model with jumps

This paper presents an efficient Monte Carlo simulation scheme based on the variance reduction methods to evaluate arithmetic average Asian options in the context of the double Heston's stochastic volatility model with jumps. This paper consists of two essential parts. The first part presents a new flexible stochastic volatility model, namely, the double Heston model with jumps. In the second part, by combining two variance reduction procedures via Monte Carlo simulation, we propose an efficient Monte Carlo simulation scheme for pricing arithmetic average Asian options under the double Heston model with jumps. Numerical results illustrate the efficiency of our method.     

Asset Accumulation: An Alternative Approach to Achieving the Millennium Development Goals

The United Nations Millennium Development Goals (MDGs) are unlikely to be achieved by 2015, owing to conceptual flaws in their design as well as the structural and political constraints faced during implementation at the country level. While criticism of the MDGs is widespread, innovative ideas on addressing these operational challenges are still scanty. By reviewing a number of experiences, including those of the Foundation for the Promotion of Local Development (PRODEL) in Nicaragua and the Ministry of Cities in Brazil, this article highlights the importance of incorporating an asset‐accumulation perspective into MDG‐related policies and programmes as a way of generating an enabling environment that opens up new opportunities for poverty reduction in the cities of low‐ and middle‐low‐income countries.     

Linguistic practice and identity work: Variation in Taiwan Mandarin at a Taipei County high school

This article examines variation in the use of two Taiwan Mandarin features, de‐retroflection of sibilant fricatives [?] → [s], and labial glide deletion [w?] → [?], in the speech of Taipei County high school students. The features become resources for the negotiation of identity positions within the highly structured school institution. I discuss the correlations between the use of Taiwan Mandarin and two social factors: membership in the small culture (Holliday 1999 ) of a particular bānjí or class, and individual aspirations. Holliday's concept of small cultures is proposed as a variant of the Community of Practice. I refer to Bucholtz and Hall's ( 2004 ) tactics of intersubjectivity framework as a possible tool for explaining variation at the school. I argue that the two Taiwan Mandarin features are invoked to perform different social goals, which is possible because they are imbued with related but significantly different sociocultural meanings (Brubaker 2012 ; Baran 2007 ).     

Application of the Bootstrap Approach to the Choice of Dimension and the α Parameter in the SIRα Method

To reduce the dimensionality of regression problems, sliced inverse regression approaches make it possible to determine linear combinations of a set of explanatory variables X related to the response variable Y in general semiparametric regression context. From a practical point of view, the determination of a suitable dimension (number of the linear combination of X) is important. In the literature, statistical tests based on the nullity of some eigenvalues have been proposed. Another approach is to consider the quality of the estimation of the effective dimension reduction (EDR) space. The square trace correlation between the true EDR space and its estimate can be used as goodness of estimation. In this article, we focus on the SIR_α method and propose a naïve bootstrap estimation of the square trace correlation criterion. Moreover, this criterion could also select the α parameter in the SIR_α method. We indicate how it can be used in practice. A simulation study is performed to illustrate the behavior of this approach.     

Composite quantile regression for varying-coefficient single-index models

ABSTRACT

The varying-coefficient single-index model (VCSIM) is a very general and flexible tool for exploring the relationship between a response variable and a set of predictors. Popular special cases include single-index models and varying-coefficient models. In order to estimate the index-coefficient and the non parametric varying-coefficients in the VCSIM, we propose a two-stage composite quantile regression estimation procedure, which integrates the local linear smoothing method and the information of quantile regressions at a number of conditional quantiles of the response variable. We establish the asymptotic properties of the proposed estimators for the index-coefficient and varying-coefficients when the error is heterogeneous. When compared with the existing mean-regression-based estimation method, our simulation results indicate that our proposed method has comparable performance for normal error and is more robust for error with outliers or heavy tail. We illustrate our methodologies with a real example.     

小额信贷经理人愿意扶贫吗？——基于西北地区贫困县152位信贷经理人的经验分析

基于西北5省15个国家级贫困县152位信贷经理人的问卷调查,分析了小额信贷经理人的扶贫意愿、行为以及影响因素。经验研究结果表明：在调研的国家级贫困县中,尽管近六成小额信贷经理人向贫困户发放过贷款,但业务量总体较少,具有信贷扶贫意愿的不到2成;性别、教育背景、收入满意度、信贷决策自主性、放贷任务以及是否完成任务对信贷扶贫业务有显著影响;性别和信贷自主权对扶贫意愿具有显著影响。由此,在信贷扶贫项目选择信贷经理人时,采取差异化策略,有序放松信贷自主权,加强扶贫效果考核,对提高金融扶贫绩效会起到积极的作用。