民族文化变迁对生态环境保护的影响——以云南为例

我国西部生态环境保护一直是各学科关注的焦点问题,但从生态环境保护的民族文化内在驱动力这一重要角度进行研究的较少。实际上,环境保护的主体是当地居民,而环境保护观念主要受到传统民族文化的影响。本文通过对云南民族文化变迁的分析,指出了对云南民族生态文化产生负面影响的因素主要来自三方面:汉文化、近现代文明、地域权力变更与“左”倾思想。最后,探讨了解决云南民族文化与生态环境保护之间的摩擦的途径。     

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.     

Farmland Investment Under Conditions of Certainty and Uncertainty

This study investigates the potential for farmland to improve mixed-asset portfolio efficiency. Three major conclusions are drawn from the research. First, in a world with certainty, farmland can be shown to statistically improve mixed-asset portfolio efficiency. Second, with the introduction of uncertainty into the portfolio allocation model, investors can justify small or no allocations of farmland in a mixed-asset portfolio, although it appears that even with uncertainty prudent investors should evaluate the asset class. Third, with respect to farmland investment and geographic diversification, the results question the ability of an optimized mean–variance portfolio to provide substantial improvement in comparison to a naïve portfolio. The marginal improvement in portfolio efficiency of an optimized farmland portfolio versus a naïve farmland portfolio is not statistically significant.     

Observable Consequences of Trading Structure Differences: On the Use of Variance Ratios in Microstructure Studies

This paper examines the variance ratio tests in studies of transitory volatility and concludes that the variance ratio is an appropriate test of trading structure differences only under certain assumptions regarding the evolution of underlying stock prices and the autocorrelation structure of returns. This result raises caution as to the interpretation of results bases upon the 24-hour variance ratio methodologies in studies of transitory volatility and trading structure effects. A numerical example indicates that errors in inferences can be severe.     

Diversification Benefits of Japanese Real Estate Over the Last Four Decades

This paper studies the benefits of diversifying into real estate and other assets that typify the wealth held by Japanese investors. We examine movements in mean variance frontiers by employing spanning tests to assess the statistical significance of frontier shifts. We also investigate the impact of shifts in mean variance frontiers before and after the precipitous decline in Japanese real estate and stock market values that began in 1990. Spanning tests show that real estate, short and long-term bonds, and Japanese equity provide significant diversification benefits. We find that mean variance frontiers shift after 1990. Statistically significant shifts are also economically important as measured by Sharpe ratio changes. Although significant, the portfolio weights on Japanese real estate are relatively small compared to their composition found in surveys of Japanese household wealth.     

The Effects of Oil Price on the Korean Economy: A Global VAR Approach

This article empirically explores the effects of oil price on the Korean economy using a Global VAR model. First, we evaluate the average connectedness of oil price with the Korean domestic variables over the precrisis period. We then investigate the time-varying contribution of oil price to the Korean financial and real sectors during and after the global financial crisis through recursive estimation. It is found that the contribution of oil price becomes very large in the case of real exports, equity prices, and real output, but plays a much less prevalent role in the remaining cases. In the meantime, the time-varying contribution of oil price to the Korean economy has not changed during and after the global financial crisis. Interestingly, we find that the Korean economy is affected mostly by overseas financial conditions in the short-term but it becomes more susceptible to oil price fluctuations in the long run, suggesting that Korea’s reliance on energy imports leaves the economy exposed to volatility in energy prices.     

吉林省农业生态旅游功能分区研究  谢 璐

随着我国城镇化进程的不断加快,生活在喧嚣都市的人们越来越向往恬静的田园风光,农业生态旅游业作为一种新型农业生产经营形式与旅游活动项目应运而生,并且越来越受到相关学者与政府的重视.文章以吉林省农业生态旅游为研究对象,分析了农业生态旅游的发展现状,指出其发展存在生态环境破坏、 基础设施落后、 管理水平较低、 产业链条较短等问题;综合考虑吉林省地形地貌特征、 气候特征、民俗风情等因素,考虑不同区域农业经济、 社会、 生态及文化的相似性与差异性,对其进行地理空间分区,大致分为东部长白山农业生态旅游功能区、 中部松辽平原农业生态旅游功能区、 西部松嫩平原农业生态旅游功能区,同时探究了各功能区的差异性特征;针对各功能区不同特征提出"政府调控-市场调节"相互配合、"农业-旅游业"相互耦合、"经济-社会-生态"相互协调、"以点带面"互联互动、"省内-省外"互学互助等发展建议,以期为当地农业生态旅游的发展提供借鉴,为促进吉林省农业生态旅游业的可持续发展提供参考.     

新会计准则影响股东权益变化因素的分析

文章针对新会计准则的颁布对股东所有者权益的变化各影响因素进行分析,选取巨潮资讯网、上海证券交易所网站、深圳证券交易所网站等公开披露的国内A股上市公司2006年的年度报告数据,对影响所有者权益变化的15个因素进行了描述性统计、单因素敏感性分析和回归分析,得出在所有的影响因素当中,长期股东权益投资差额对股东权益的变化的影响是显著的。     

人民币新汇制改革的贸易效应之谜——基于我国对外经济贸易特征视角的协整研究和脉冲分解

关于人民币汇制改革在我国贸易均衡方面的表现,文章运用Johansen模型揭示出:人民币升值是近两年贸易顺差形成的主要推动因素,马歇尔-勒纳条件在我国并不适用;依托于我国现行的经济贸易特征,未来一段时间我国仍将唱响贸易顺差的主旋律;在人民币加速升值的今天注重升值节奏对于保持我国贸易收支的稳定不容忽视,这一观点通过脉冲响应函数与方差分解得到了有效印证.     

Implied integrated variance and hedging

If the volatility is stochastic, stock price returns and European option prices depend on the time average of the variance, i.e. the integrated variance, not on the path of the volatility. Applying a Bayesian statistical approach, we compute a forward-looking estimate of this variance, an option-implied integrated variance. Simultaneously, we obtain estimates of the correlation coefficient between stock price and volatility shocks, and of the parameters of the volatility process. Due to the convexity of the Black–Scholes formula with respect to the volatility, pricing and hedging with Black–Scholes-type formulas and the implied volatility often lead to inaccuracies if the volatility is stochastic. Theoretically, this problem can be avoided by using Hull–White-type option pricing and hedging formulas and the integrated variance. We use the implied integrated variance and Hull–White-type formulas to hedge European options and certain volatility derivatives.