供给侧结构性改革推进四川省玉米产业转型发展策略

[目的]随着中国粮食产量的"十二连增",国内农业生产的主要矛盾也逐步由总量不足转向结构性矛盾,其中玉米产业面临的矛盾尤为突出,玉米产业结构调整是我国农业供给侧结构性改革推进中的首要任务。四川既是全国玉米生产的重要省份,也是玉米消费大省,如何推进玉米产业供给侧结构性改革、实现产业转型发展还有待于思考。[方法]文章从供需平衡、供给结构、供给效益和供给效率4个角度分析了四川玉米产业供给侧的特征,同时从要素供给、社会化服务和产业链3个方面分析了影响四川玉米产业发展的制约因素。[结果]四川玉米消费结构呈现多元变化,从口粮消费为主转变为以饲料、工业加工消费为主;草食畜牧业发展迅速,饲用作物需求量增大;农业科技支撑力度明显,玉米育种成就突出。[结论]提出从优化品种结构、推行种养循环、培育新型经营主体、拓展产业链等方面推进四川玉米产业的转型升级。     

Distance-sensitivity of German exports: first evidence from firm-product level data

This article uses a tailor-made new data set of 7 580 251 observations for German exports at the firm-product-destination level to estimate a gravity equation and to investigate the link between the amount of firms’ exports and the distance to destination countries. It is shown that, in line with stylized facts based on aggregate data, the quantity of exports declines significantly with distance within a firm for a given product.     

Modeling and Measuring Economic Reality: Reply to the Reviews

To begin with, we'd like to express our appreciation to our three commentators for their thoughtful and helpful reviews. Like the founders of the subject, we believe, and our reviewers seem to agree, that structural econometrics has the potential to enable us to develop serious working models of how different economies actually operate, and also to tell us something about the changing patterns of their growth and transformation. But both we and our reviewers agree that there is a great deal wrong with the way econometrics is practiced today.     

关于复数运算在高次方程中的运用

随着office2010版开发,复数函数的运算的完善为高次方程的完整解提供了技术上的有力保障。     

Convergence analysis and optimal strike choice for static hedges of general path-independent pay-offs

In this paper, we propose a new algorithm to find the optimal static replicating portfolios for general path-independent nonlinear pay-off functions and give an estimate for the rate of convergence that is absent in the literature. We choose the static replication by designing an adaptation function arising in the error bound between the nonlinear pay-off function and the linear spline approximation and derive the equidistribution equation for selecting the optimal strikes. The numerical tests for variance swaps, swaptions, static quadratic hedges and also for a jump-diffusion process, allowing for the default of the underlying asset, show that the proposed iterative equidistribution equation algorithm is simple, fast and accurate. The paper generalizes and improves the results on static replication and approximation in the literature.     

发达国家住房福利政策的演变及启示——我国公租房领域供给侧结构性改革探析

我国公租房领域存在投资主体单一、政府财政压力大、市场参与度不够、配置低效、供需失衡及错配、贫富分区程度加大等问题，需通过推进供给侧结构性改革来予以解决。发达国家住房福利政策的演变表明，住房政策应与住房市场供需状况相适应，政府所扮演的角色须从“公共住房的直接供给者”走向“市场化供给的环境营造者”，即从“补砖头”到“补人头”是住房福利政策演进的必然趋势。我国公租房领域供给侧结构性改革应与住房供求情况相匹配。一方面，要转变政府职能，从政府实物配给逐步过渡到市场化供给；另一方面，要积极打造健康的住宅租赁投资市场以促进公租房供给市场化，并通过开发配建和货币化补贴等措施促成公租房“隐形化”混合居住模式。     

Moderating Role of Gender in the Relationship between Hotel Service Quality Dimensions and Tourist Satisfaction

Gender has frequently been identified as one of the key attributes and predictors in developing marketing strategy. This study examines the moderating role of gender in the relationship between hotel service quality dimensions and tourist satisfaction with hotel service delivery. The results derived from multi-group structural equation modeling via the AMOS 5.0 computer program revealed that gender significantly moderated the relationship between service quality dimensions and tourist satisfaction with hotel service delivery. Empathy and tangibles both contributed as the most important significant predictors of tourist satisfaction with hotel service delivery for male tourists as opposed to female tourists. It is statistically confirmed that men and women appear to respond to different aspects of a service encounter when making judgments about their satisfaction.     

Household indebtedness in Korea: Its causes and sustainability

This paper investigates why household debt in Korea has increased so rapidly over the past decade and whether it is sustainable, adopting a multi-faceted approach which includes a time series analysis, a quantitative analysis based on household panel data, and an analysis using a debt dynamics equation derived from the household budget constraint. A regression analysis reveals that household debt growth has been significantly related to house price increases, banks’ lax attitudes toward household lending, and financial institutions’ favorable funding conditions. Also 70–80% of the total debt increase has been accounted for by high income or newly indebted households. The debt dynamics equation analysis shows that the rapid rise in the ratio of household debt to disposable income is attributable not only to the increase in household asset purchases but also to the dampened growth in disposable income and the reduced savings rate. The sustainability analyses indicate that Korean households’ debt sustainability is unlikely to deteriorate sharply within a short period of time unless two extreme scenarios, under which house prices decline by 5% a year over the next five years, or a significantly large macroeconomic shock similar to the 1997 crisis hits the economy, would be realized.     

Optimal constrained investment in the Cramer-Lundberg model

We consider an insurance company whose surplus is represented by the classical Cramer-Lundberg process. The company can invest its surplus in a risk-free asset and in a risky asset, governed by the Black-Scholes equation. There is a constraint that the insurance company can only invest in the risky asset at a limited leveraging level; more precisely, when purchasing, the ratio of the investment amount in the risky asset to the surplus level is no more than a; and when short-selling, the proportion of the proceeds from the short-selling to the surplus level is no more than b. The objective is to find an optimal investment policy that minimizes the probability of ruin. The minimal ruin probability as a function of the initial surplus is characterized by a classical solution to the corresponding Hamilton-Jacobi-Bellman (HJB) equation. We study the optimal control policy and its properties. The interrelation between the parameters of the model plays a crucial role in the qualitative behavior of the optimal policy. For example, for some ratios between a and b, quite unusual and at first ostensibly counterintuitive policies may appear, like short-selling a stock with a higher rate of return to earn lower interest, or borrowing at a higher rate to invest in a stock with lower rate of return. This is in sharp contrast with the unrestricted case, first studied in Hipp and Plum, or with the case of no short-selling and no borrowing studied in Azcue and Muler.     

基于结构方程模型的集聚农户共生认知及影响因素分析:以重庆市为例

研究目的:探讨对集聚农户共生、集聚区土地利用率提高的影响因素,为提升农户共生的认知水平、优化农户共生关系及促进资源的节约集约利用提供有效路径及理论指导。研究方法:参与式农户调查,结构方程模型。研究结果:(1)户主自身特征、农户家庭特征、集聚共生效益特征及外部环境与政策特征这4类外源潜变量对农户共生认知产生重要影响且影响程度大小不同,其中,集聚共生效益特征的影响最为显著,外部环境与政策特征、户主自身特征和农户家庭特征的影响依次减弱;(2)是否为干部、对原集聚模式的满意度、是否促进农户生产生活条件和政府对集聚区的补贴力度分别对这4类外源潜变量具有较好的解释能力。研究结论:显化农户共生效益、增强"精英"农户及村干部的正向引导、提升农户成员受教育水平、培养农户"共生共荣"理念等是深化农户共生关系,促进和谐乡村人居环境建设的重要路径。