The analysis of proportions in agricultural experiments by a generalized linear mixed model

This paper is concerned with the statistical analysis of proportions involving extra-binomial variation. Extra-binomial variation is inherent to experimental situations where experimental units are subject to some source of variation, e.g. biological or environmental variation. A generalized linear model for proportions does not account for random variation between experimental units. In this paper an extended version of the generalized linear model is discussed with special reference to experiments in agricultural research. In this model it is assumed that both treatment effects and random contributions of plots are part of the linear predictor. The methods are applied to results from two agricultural experiments.     

“汇改”后汇率变动对股票市场的影响——基于具体行业股票收益率的实证分析

使用GARCH和分位数回归模型,以11个具体行业上市公司为样本,对2005年7月＂汇改＂后人民币汇率变动与股票市场中行业股票收益率波动的相关性进行分析,研究结果表明：相对于即期汇率,以远期汇率为代表的汇率预期对行业股票收益率影响更为明显;预期汇率对行业股票收益率的影响具有明显的阶段性特征;在第一阶段,受远期汇率影响的行业主要对远期汇率的升值比较关注,而在第三阶段,不同行业对即期汇率和远期汇率的反应呈现多样化。     

基于地理加权回归的住宅地价测算方法及实证

建立样点地价与定级作用分值(因素影响分值)之间的函数关系,是表达地价空间分异规律、批量测算地价的关键。通过GWR与地价传统评估方法(OLR)进行比较,以北海市住宅用地为例,进行建模测算和分析。研究表明:(1)GWR模型模拟的北海市住宅用地地价空间分异与北海自身资源禀赋及城市发展方向相一致;(2)GWR模型的拟合度和检验精度及解释能力均优于OLR模型;(3)GWR方法构建的地价拟合表面与现有的北海市住宅用地土地级别与基准地价成果图件总体上具有一致性,可以用于基准地价测算或其他批量地价测算应用需求中。     

三段截尾变量小值概率上界的估计

在给定随机变量X∈[-a,M-a],M＞0,a≥0,且EX＝m1,EX2＝m2的条件下,研究了三段线性函数max（0,X,mX-z）的概率分布的上界,其中m＞1,z＞0,M＞max（m1,z/（m-1））。通过简单的变换,将概率问题转化成了均值问题后,应用对偶的理论,构造控制函数,得到了概率分布的上界。是X∈[-a,＋∞],a≥0,且EX＝m1,EX2＝m2,三段线性函数max（0,X,mX-z）的概率分布（左尾）界的推广。具有很强的理论和重要的实际意义。     

Cultural differences and entrepreneurial behaviour: an intra-country cross-cultural analysis in Cape Verde

Two recent research trends give rise to the current work: the need to extend the conclusions reached in entrepreneurship studies to other cultural contexts, particularly important given the interest in stimulating the creation of firms in recently industrialised and less developed countries; and the need to go beyond the axiom ‘nation=culture’ in favour of the multiple cultures perspective. With these antecedents, we present the current work, which aims to answer two research questions: (1) are the cultural values associated in the literature with venture creation generalisable to different cultural contexts? (2) are there intra-cultural differences in a country generating differences in the entrepreneurial behaviour of its population? Thus, this work contributes to extending knowledge about entrepreneurship and international cross-cultural management by taking the novel approach of studying the cultural values and the decision to create a venture from the intra-cultural differences perspective. A sample of 448 individuals, obtained in the Republic of Cape Verde and analysed in six territories within this country, allows us to confirm the existence of cultural differences in individualism between regions of the Republic of Cape Verde, as well as their capacity to explain entrepreneurial behaviour in these regions.     

What factor contributes to productivity growth of Chinese city banks: The role of regional difference

This study pays more attentions to investigate the performance of Chinese city banks, which can make up the blanks large banks left in the financing market, further improving local economic development. The study modifies the profit productivity indicator of Juo et al. (2015) under the short-run assumption to measure the profit productivity and its components. Our study finds that there exists a significant difference among banks by regions, and the eastern regional city banks have a best profit efficiency, but decline more than the others. The decomposed component, price effect, plays a most important role to explain the profit productivity change.     

Some mathematical aspects of price optimisation

Calculation of an optimal tariff is a principal challenge for pricing actuaries. In this contribution we are concerned with the renewal insurance business discussing various mathematical aspects of calculation of an optimal renewal tariff. Our motivation comes from two important actuarial tasks, namely (a) construction of an optimal renewal tariff subject to business and technical constraints, and (b) determination of an optimal allocation of certain premium loadings. We consider both continuous and discrete optimisation and then present several algorithmic suboptimal solutions. Additionally, we explore some simulation techniques. Several illustrative examples show both the complexity and the importance of the optimisation approach.     

Does the stock market contain information about economic growth? Time-varying out of sample causality tests

We present a new approach to conduct time-varying out of sample causality tests and apply our method to examine the information content of the stock market for economic growth in the US context. We show that equity valuations convey little information in the period after the 1960s. Particularly, there is no evidence to suggest that the recent bull market in equities is indicative of higher future economic growth. Hence, our results are against the argument that the stock market should be included as a leading indicator in economic policymaking.     

A Hermite-spline model of post-retirement mortality

ABSTRACT

We present a model for post-retirement mortality where differentials automatically reduce with increasing age, but without the fitted mortality rates for subgroups crossing over. Selection effects are catered for, as are age-modulated time trends and seasonal variation in mortality. Central to the model are Hermite splines, which permit parsimonious modelling of complex risk factors in even modest-sized portfolios. The model is therefore suitable for the stand-alone analysis of experience data for reinsurance, bulk annuities and longevity swaps. We also illustrate the contrast between the statistical significance of a risk factor and its financial significance and discuss reasons why one might include risk factors like season that are not directly financially significant.     

生态语言学视野中湘南瑶语的保存和变异——以榴星瑶语为例

湖南永州东安榴星村有汉瑶两个民族,现代榴星村里有一种瑶语方言,两种汉语方言。这三种方言共存于一个语言生态系统里。汉语方言处于优势地位,榴星瑶语的演变是语言的生态变异,瑶语在竞争中仍保持了自己的特色但又趋于濒危。