我国农业水资源问题分析

水资源素有“农业生产的命脉”之称。由于多方面因素影响，我国农业水资源供需缺口越来越大．严重危及我国未来农业生产安全。本文分析了我国的农业水资源现状及存在的问题．并提出若干保护农业水资源安全的对策。     

投资与通货膨胀-紧缩的联系:来自中国的经验证据

基于Toda-Yamamoto长期因果检验程序和广义脉冲反应技术,本文首先研究了全社会实际固定资产投资与零售价格水平变动之间的长期因果及其冲击-动态反应关系,然后进一步考察了货币供给量M1和贸易依存度在促成上述关系中所扮演的角色.其研究结论为:(1)货币供给量M1是唯一的外生变量,其增长不是价格水平变动的直接因,而是通过全社会实际固定资产投资间接地成为价格水平变动的因;(2)贸易依存度和全社会实际固定资产投资之间存在双向因果联系,前者只能通过后者间接地成为价格水平变动的因;(3)中国对外开放既消化又强化了中国生产能力过剩,但消化胜于强化;(4)投资一个单位正向冲击在开始的2-4年左右导致相对温和的通货膨胀,但后五年左右将导致相对严重的通货紧缩.     

公共支出对我国技术效率的影响分析

文章首先应用随机前沿方法,估计了我国31省市的时变随机前沿生产函数模型,结果表明提高公共支出占GDP的比例能显著地降低技术效率,而提高公共支出的组成部分占GDP的比例对技术效率有显著的促进作用,其现实意义就是优化公共支出结构对我国的技术效率有促进作用.其次,计算了我国31省市的技术效率,结果发现东部与西部之间的技术效率差距较大,而且在进一步扩大之中.再次,对TFP变化率进行了分解,分析表明:不论是从全国还是从东中西部三地区看,对技术效率影响最大的因素都是规模经济性,而技术进步和资源配置效率影响较小.最后,根据我国目前以规模经济性对TFP变化率为主要影响因素的实际情况,指出从公共收支视角来提高技术进步和资源配置效率对TFP变化率的影响,缩短东西部技术效率的差距,是一条高效率的公共支出发展之路.     

会计信息化发展及其影响

在信息化时代,会计信息化应该面向国民经济和社会信息化,会计信息化的主要任务是会计职业判断的智能化,在此基础上,将社会经济的监督权与会计信息的生产整合,创新一种新的会计信息生产方式。会计信息化对会计理论与实践产生了巨大的冲击与革新。     

Two–step sequential sampling

Choosing the sample size in advance is a familiar problem: often, additional observations appear to be desirable. The final sample size then becomes a random variable, which has rather serious consequences.
Two such sample extension situations will be considered here. In the first situation, the observed sample variance determines whether or not to double the original sample size. In the second situation, the variances observed in two independent samples are compared; their ratio determines the number of additional observations.     

Heteroscedasticity and Non-Monotonic Efficiency Effects of a Stochastic Frontier Model

We consider a model that provides flexible parameterizations of the exogenous influences on inefficiency. In particular, we demonstrate the model's unique property of accommodating non-monotonic efficiency effect. With this non-monotonicity, production efficiency no longer increases or decreases monotonically with the exogenous influence; instead, the relationship can shifts within the sample. Our empirical example shows that variables can indeed have non-monotonic effects on efficiency. Furthermore, ignoring non-monotonicity is shown to yield an inferior estimation of the model, which sometimes results in opposite predictions concerning the data.     

中国石油产量的VERHULST模型的建立与分析

随着我国国民经济的快速发展,对能源的需求逐渐增大,尤其是对石油的需求逐年上升,石油的供应问题已成为普遍关注的问题。我国石油资源赋存条件差,石油增储难度大,大多数主力油田已进入中后期开采阶段,石油产量增产难度大。面对日益增加的石油需求,及时准确、科学地预测我国今后一段时期石油产量,对于制定石油需求和石油战略储备计划具有重要的现实意义。因此,根据我国石油产量变化特点,建立了Verhulst模型,经过检验,模型预测精度很高,并对2020年以前的石油产量进行了预测。     

The impact of credit constraints on the performance of Chinese agricultural wholesalers

This article evaluates the impact of credit constraints on the performance of Chinese agricultural wholesalers. We estimate a stochastic frontier function using transaction and credit data of agricultural wholesalers from across China to estimate the efficiency and productivity impacts of credit constraints on sales of affected agricultural wholesalers. Empirical results show that micro- and smaller wholesalers are disproportionally impacted by credit constraints and that eliminating these constraints would increase the sales of affected agricultural wholesalers by approximately 15%. Thus, policies aimed at providing credit access for these wholesalers would significantly boost the performance of smaller agricultural wholesalers while improving the overall performance of the Chinese food supply chain without requiring additional non-credit inputs.     

Modelling the dynamics of Bitcoin and Litecoin: GARCH versus stochastic volatility models

We examine and compare a large number of generalized autoregressive conditional heteroskedastic (GARCH) and stochastic volatility (SV) models using series of Bitcoin and Litecoin price returns to assess the model fit for dynamics of these cryptocurrency price returns series. The various models examined include the standard GARCH(1,1) and SV with an AR(1) log-volatility process, as well as more flexible models with jumps, volatility in mean, leverage effects, t-distributed and moving average innovations. We report that the best model for Bitcoin is SV-t while it is GARCH-t for Litecoin. Overall, the t-class of models performs better than other classes for both cryptocurrencies. For Bitcoin, the SV models consistently outperform the GARCH models and the same holds true for Litecoin in most cases. Finally, the comparison of GARCH models with GARCH-GJR models reveals that the leverage effect is not significant for cryptocurrencies, suggesting that these do not behave like stock prices.     

Poverty Traps, Indeterminacy, and the Wealth Distribution

We consider a one-sector growth model in continuous time with a production externality and endogenous labor supply. There is a continuum of households who have identical preferences but differ with respect to their initial wealth. We show that there exist economies such that an indeterminate steady state exists for some wealth distribution but not for others. A second result is that a redistribution of wealth may drive the economy from a steady state with strictly positive output to a poverty trap in which output converges asymptotically to zero. These results indicate that differences in the wealth distribution may be responsible for drastic differences in the long-run standard of living. Journal of Economic Literature Classification Numbers: D31, D50, O41.