2017年轮国际比较项目住房服务比较方法及其对中国的影响

住房服务比较一直是国际比较项目(ICP)中的一个难点领域,即将结束的2017年轮ICP在实践中也十分关注住房领域,并做出了系列改进。本文主要梳理现阶段区域住房服务比较中的3种方法和亚洲开发银行创建的新方法的基本原理、优缺点及适用范围,以及介绍全球住房服务比较中的区域链接方法、剖析方法存在的问题;同时,本文进一步评估了亚太区域比较方法和区域链接方法对中国的可能影响。研究发现,现阶段的区域住房服务比较方法和区域链接方法都存在一定的不足,亚太区域比较方法以及ICP区域链接方法都存在低估中国住房服务购买力平价的可能。本文提出,在中国可以提供准确的租金数据背景下,为避免亚太区域因整体数据质量较差而被迫选择较差的方法所带来的不利影响,中国应在亚太区域尝试寻求比较方式的转变,以提高自身比较结果的准确性。     

海外上市地点和企业投资:纳斯达克、香港、新加坡上市企业比较

本文研究海外上市地点与企业投资之间的关系。香港和新加坡在信息环境和制度环境方面相差不大,而纳斯达克在这两个方面均存在显著优势。良好的信息环境和制度环境可以减弱信息不对称的程度,缓解企业面临的代理问题,从而减少企业投资不足或者投资过度的行为。与此相一致,我们发现相比在香港和新加坡上市而言,在纳斯达克上市的企业其投资—现金流敏感性更低,规模小、上市时间短、应计项高、杠杆率低的企业受影响更大。进一步研究发现,在纳斯达克上市既可以缓解企业的投资不足,也可以降低企业的投资过度,这表明纳斯达克信息环境优势和制度环境优势共同作用提高了企业的投资效率。     

The spokane heart study: weibull regression and coronary artery disease

Coronary artery calcium is a marker of coronary artery disease and measures the progression of atherosclerosis. It is measured by electron beam computed tomography, and the measured amount of coronary artery calcium is highly skewed to the right and left censored. The distribution of coronary artery calcium appears to be Weibull. We propose a Weibull regression model and we analyze the data using these techniques. Our analysis is based on data from the Spokane Heart Study, which is a cohort of about a thousand subjects that are assessed every two years for coronary artery calcium and risk factors of coronary artery disease. The major focus of the heart study is to determine the natural history of atherosclerosis in its early phase, and we analyze the data as a cross-sectional study with 859 subjects. We would also like to highlight the use of Weibull regression techniques in situations like this, where we have extreme right skewed data. Our main emphasis will be on examining the effect of the traditional risk factors of age, gender, lipid profile (cholesterol and HDL), patient history of lipid abnormality, hypertension, and smoking, and other family history risks on coronary artery calcium. We found that the most important factors influencing the disease were age, sex, and patient history of smoking and lipid abnormality.     

Quasi-Likelihood Approach to Bioavailability and Bioequivalence Analysis

The outcomes AUCT (area-under-curve from time zero to time t) of n individuals randomized to one of two groups TR or RT, where the group name denotes the order in which the subjects receive a test formulation (T) or a reference formulation (R), are used to assess average bioequivalence for the two formulations. The classical method is the mixed model, for example, proc mixed or proc glm with random statement in SAS can be used to analyze this type of data. This is equivalent to the marginal likelihood approach in a normal–normal model. There are some limitations for this approach. It is not appropriate if the random effect is not normally distributed. In this article, we introduce a hierarchical quasi-likelihood approach. Instead of assuming the random effect is normal, we make assumptions only about the mean and the variance function of the random effect. Our method is flexible to model the random effect. Since we can estimate the random effect for each individual, we can check the adequacy of the distribution assumption about the random effect. This method can also be used to handle high-dimensional crossover data. Simulation studies are conducted to check the finite sample performance of the method under various conditions and two real data examples are used for illustration.     

Focused Information Criterion and Model Averaging in Quantile Regression

In this article, we study model selection and model averaging in quantile regression. Under general conditions, we develop a focused information criterion and a frequentist model average estimator for the parameters in quantile regression model, and examine their theoretical properties. The new procedures provide a robust alternative to the least squares method or likelihood method, and a major advantage of the proposed procedures is that when the variance of random error is infinite, the proposed procedure works beautifully while the least squares method breaks down. A simulation study and a real data example are presented to show that the proposed method performs well with a finite sample and is easy to use in practice.     

An Exponential-Gamma Convolution Model for Background Correction of Illumina BeadArray Data

Illumina BeadArrays are becoming an increasingly popular Microarray platform due to its high data quality and relatively low cost. One distinct feature of Illumina BeadArrays is that each array has thousands of negative control bead types containing oligonucleotide sequences that are not specific to any target genes in the genome. This design provides a way of directly estimating the distribution of the background noise. In the literature of background correction for BeadArray data, the information from negative control beads is either ignored, used in a naive way that can lead to a loss in efficiency, or the noise is assumed to be normally distributed. However, we show with real data that the noise can be skewed. In this study, we propose an exponential-gamma convolution model for background correction of Illumina BeadArray data. Using both simulated and real data examples, we show that the proposed method can improve the signal estimation and detection of differentially expressed genes when the signal to noise ratio is large and the noise has a skewed distribution.     

为什么农民无法从“公司+农户”中受益

为了探究以“公司+农户”为主体的农业产业化经营蓬勃发展与农民增收乏力之间的矛盾,文章以江西省部分农业龙头企业和农户的调查资料为基础,从家庭经营规模、利益联结机制和龙头企业实力三个方面分析了导致目前农民无法受益的原因:以妇女和老人为农业生产主体的农村“空心化”现状使得参与农业产业化经营的农户家庭经营规模偏小;农民和公司的主体地位不对称,农民难以参与农产品加工、销售环节的利润分配,农户和公司之间是松散型利益联结机制;农业龙头企业普遍是小企业,生存的压力已经令其自顾不暇,即使有心也无力让为数众多的农户参与到有限利润的分配中来.     

The Changing Mode of Legal Regulation of Labor Relations in China

At present, Chinese labor relations operate under a unitary model of legal regulation in which labor law is applied to workers “as a whole, with everyone treated equally.” This causes a number of problems. In reality, due to constantly changing modes of employment and the flexibility of workers’ “affiliation,” forms of employment are highly diverse. In addition to regular employees, there are also “quasi-employees” (employee-like persons) whose affiliation is quite weak, and other special employees. This necessitates the updating of the legislative thinking behind labor laws. While holding fast to the assumption that workers are a vulnerable group, we should review the differences between different types of employee and draw up the corresponding regulations on the basis of specific situations. Where legislative technique is concerned, we should do away with the traditional one-size-fits-all legislative model in favor of a dedicated model that targets particular types of subject and particular circumstances. We should abandon the traditional old-fashioned model in which “all labor law provisions apply” or “no labor law provisions apply” and categorize employees in such a way as to provide special rules for quasi-employees, special employees and employees of special employers. The legal regulation of labor relations should be based on categorization and differential treatment.