Shape spaces for prealigned star-shaped objects—studying the growth of plants by principal components analysis

Summary.  We analyse the shapes of star-shaped objects which are prealigned. This is motivated from two examples studying the growth of leaves, and the temporal evolution of tree rings. In the latter case measurements were taken at fixed angles whereas in the former case the angles were free. Subsequently, this leads to different shape spaces, related to different concepts of size, for the analysis. Whereas several shape spaces already existed in the literature when the angles are fixed, a new shape space for free angles, called spherical shape space , needed to be introduced. We compare these different shape spaces both regarding their mathematical properties and in their adequacy to the data at hand; we then apply suitably defined principal component analysis on these. In both examples we find that the shapes evolve mainly along the first principal component during growth; this is the 'geodesic hypothesis' that was formulated by Le and Kume. Moreover, we could link change-points of this evolution to significant changes in environmental conditions.     

信贷政策效应的非对称性、信贷扩张与经济增长

 本文从银行贷款的角度出发,运用马尔可夫区制转移向量自回归模型（MS-VAR）对1992～2008年间的信贷增长率与经济增长率以及通货膨胀率的关系分别进行总量研究。检验结果表明,我国的经济增长路径和通货膨胀路径均有明显的三区制特征;各区制的持续期、转移概率均存在非对称的特点;信贷增长率与经济增长率以及通货膨胀率在各区制的同期相关系数明显不同,并且表现出结构性变化。     

安徽省金融发展与经济增长：基于VAR和VEC模型的实证

安徽通过改革开放以来三十一年的发展,金融发展在一定程度上促进了经济的增长,相关实证分析显示：金融规模的扩张和股票市场的发展不同程度地促进了经济的增长,虽然股票市场的发展滞后到第七期对经济增长的贡献才超过了金融规模的扩张对经济增长的贡献,但其贡献度一直在增长,这表明,虽然金融规模的扩张对经济增长的贡献仍然较大,但是成立只有十几年的股票市场的发展对经济增长的贡献具有很大的潜力;而金融发展的效率对经济增长的贡献有限,且有些时期对经济增长呈负作用;保险市场的发展并没有表现出对经济增长的显著促进作用。基于实证分析的结果,为了安徽的金融发展更快更全面地促进经济增长,安徽股票市场的发展应摆在比传统金融中介发展更优先的位置,应继续加大企业从股票市场的融资力度,同时应大力发展多元化金融体系来提高金融发展效率,加快保险机构改革并提高保险业经营水平。     

"员工流动成长效应":结构模型构建与实证分析

本文分析了"员工流动成长效应",通过访谈和问卷调查获得数据,采用项目分析、探索性因子分析以及验证性因子分析等方法,构建和检验了"员工流动成长效应"的结构模型。研究表明,"员工流动成长效应"是个并列的七因子构念,这七个因子包括发展空间、创新能力、社会能力、职业能力、自我认知、工作业绩和报酬水平。文章通过ANOVA差异分析检验了主动流动与被动流动两种流动类型"员工流动成长效应"的差异。结果表明,主动流动与被动流动在发展空间、社会能力、职业能力、工作业绩以及报酬水平五个方面存在显著差异,而在创新能力、自我认知两个方面的差异则不显著。     

General multivariate linear models for longitudional studies

Longitudinal studies occcur frequently in many different disciplines. To fully utilize the potential value of the information contained in a longitudinal data, various multivariate linear models have been proposed. The methodology and analysis are somewhat unique in their own ways and their relationships are not well understood and presented. This article describes a general multivaritate linear model for longitudinal data and attempts to provide a constructive formulation of the components in the mean response profile. The objective is to point out the extension and connections of some well-known models that have been obscured by different areas of application. More imporiantly, the model is expressed in a unified regression form from the subject matter considerations. Such an approach is simpler and more intuitive than other ways to modeling and parameter estimation. As a cmsequeace the analyses of the general class cf models for longitudional data can be casily implemented with standard software.     

A Comparison of REML and Covariance Adjustment Method in the Estimation of Growth Curve Models

The classical growth curve model is considered when one continuous characteristic is measured at q time points. The covariance adjusted estimator of growth curve parameters is the OLS estimator adjusted using analysis of covariance. The covariates are obtained from functions of within individuals error contrasts. On the other hand, REML estimators emerge from maximization of the likelihood of OLS residuals. We compare the efficiency of estimators of growth curve parameters obtained by REML with that of covariance-adjusted least squares estimators with covariates selected via CAIC.     

通货膨胀预期、企业成长性与企业投资

本文实证检验了通货膨胀预期对企业投资行为的影响及其内部机理来分析通货膨胀预期变化的经济后果。研究发现,宏观预期通货膨胀率的上升会促使微观企业增加当期资本支出规模,但是降低投资效率。进一步分析结果表明：第一,预期通货膨胀率越高,高成长性企业的投资水平显著提高,投资效率显著下降,这一结果在低成长性企业中并不显著;第二,宏观预期通货膨胀率升高,银行更愿意借款给企业。这一结果在高成长性企业中同样显著,在低成长性企业中并不显著。这说明通货膨胀预期通过外部融资促使公司投资,高成长性企业比低成长性企业能够获得更多的银行贷款,从而增加资本投资,而低成长性企业受通货膨胀预期的影响被弱化。     

宽带对中国经济增长影响的实证分析

本文运用2000年至2011年中国宽带渗透省际面板数据,研究了宽带与中国经济增长之间的关系,发现宽带引入和渗透对中国经济增长起到了显著推动作用,2000年到2011年的数据表明,宽带渗透率每增长10% 能带动人均GDP年增长率增加约0.19个百分点。分析表明宽带渗透对经济增长的贡献存在一定的网络效应,当宽带渗透率达到约10%后,宽带渗透对人均GDP年增长率的贡献率增加。此外,宽带对中国经济增长的影响具有区域差异性,宽带对于东部、中部经济发展的推动作用显著,而对西部还不明显,可能的原因是西部信息化应用水平与东、中部地区还有较大差距。截止2012年,中国宽带渗透水平以及宽带传输速率与发达国家还有明显差距,并有进一步加大的趋势,实施宽带中国战略具有现实紧迫性。     

Institutions and Economic Outcomes: A Dominance-Based Analysis

An important issue in both welfare and development economics is the interaction between institutions and economic outcomes. While welfarists are typically concerned with how these variables contribute to overall wellbeing, empirical assessments of their joint contribution are limited. Development economists, on the other hand, have focused extensively on whether institutions cause or are caused by growth yet the relevant literature is still rife with debate. In this article, we use a notion of distributional dominance to tackle both the measurement of multivariate welfare and the evaluation of inter-temporal dependence without hindrance from the mix of discrete (political) and continuous (economic) variables in our data set. On the causality front, our results support the view that institutions promote growth more than growth promotes institutions. On the welfare front, we find that economic growth had a positive impact from 1960 to 2000 but declines in institutional quality over the earlier part of this period were sufficient to produce a decline in overall wellbeing until the mid-1970s. Subsequent improvements in institutions then reversed the trend and, ultimately, wellbeing in 2000 was higher than that in 1960.     

Industry Implications of Value Creation and Appropriation Investment Decisions*

Managers face a critical task in making firm investment decisions that are targeted toward creating and appropriating value. As managers weigh their resource investment decisions, we argue that these investments have a direct impact on the growth and volatility of the firm's industry. With data covering 377 industries across 16 years, we investigate relationships for aggregate firm investments on the growth and volatility of industry profit and sales. Results reveal important, complex relationships between investment in value creation and appropriation and different elements of the industry environment. Implications for management theory and practice are discussed.