微波提取酵母胞内甘油的分析方法初探

本文探讨了面包酵母胞内甘油分析的预处理方法——微波破碎法。通过单因素实验分析,确定了胞内甘油的提取条件:酵母细胞用微波破碎3次、每次破碎10 s、间隔5 s,然后用10 mL蒸馏水提取30 min得到胞内甘油,此法简便、易提取,适用于天然产物的快速提取。     

绿色环保军用食品的研究与进展

军用野战食品是保证战士饮食的重要食物,对提高战士的身体素质、提升军队的战斗力具有至关重要的作用。各国军队首脑对此都十分重视,将此项内容作为军队建设的重要内容。基于此,本文综述了相关学者对军用食品的研究,以期为相关学者提供借鉴。     

Adoption of farm‐based irrigation water‐saving techniques in the Guanzhong Plain,China

This article analyses adoption of farm‐based irrigation water saving techniques, based on a cross‐sectional data set of 357 farmers in the Guanzhong Plain, China. Approximately 83% of the farmers use at least one farm‐based water‐saving technique. However, the traditional, inefficient techniques border and furrow irrigation are still prevalent whereas the use of advanced, more efficient techniques is still rather rare. We develop and estimate an adoption model consisting of two stages: awareness of water scarcity and intensity of adoption. We find that awareness of water scarcity and financial status enhance adoption of more advanced techniques whereas access to better community‐based irrigation infrastructure discourages it. We furthermore find both community‐based irrigation infrastructure and farm‐based irrigation water‐saving techniques have mitigating effects on production risk. From the results it follows that adoption can be stimulated via financial support and via extension aimed at enhancing awareness of water scarcity.     

Latent vs. Observed Variables: Analysis of Irrigation Water Efficiency Using SEM and SUR

In this paper we compare conceptualising single factor technical and allocative efficiency as indicators of a single latent variable, or as separate observed variables. In the former case, the impacts on both efficiency types are analysed by means of structural equation modeling (SEM), in the latter by seemingly unrelated regression (SUR). We compare estimation results of the two approaches based on a dataset on single factor irrigation water use efficiency obtained from a survey of 360 farmers in the Guanzhong Plain, China. The main methodological findings are that SEM allows identification of the most important dimension of irrigation water efficiency (technical efficiency) via comparison of their factor scores and reliability. Moreover, it reduces multicollinearity and attenuation bias. It thus is preferable to SUR. The SEM estimates show that perception of water scarcity is the most important positive determinant of both types of efficiency, followed by irrigation infrastructure, income and water price. Furthermore, there is a strong negative reverse effect from efficiency on perception.     

Value of hedge and expected returns

We demonstrate how it is possible to generate value for an investor with a hedge attached to the buy-and-hold strategy of an S&P 500 index fund. We study the S&P 500 index portfolio (not including dividends) and the value-weighted S&P 500 index portfolio (including dividends) of the Center for Research in Securities Prices for 1967:01–2011:12, using the capacity utilization and the unemployment rates in real time to determine if a hedge position should be initiated or closed. A hedge is initiated if the capacity utilization, the unemployment rate or a combination of the two signals a contraction in the real economy. The hedge position is closed if it signals otherwise an expansion. We use utility gains (Campbell and Thompson 2008), the manipulation-proof performance measure (MPPM) statistics (Ingersoll et al. 2007) and the P-Sharpe ratio (Bailey and López de Prado 2012) to evaluate the performance of a particular hedge strategy. The empirical results show that there are infinitely many hedges that can generate positive utility gains, higher MPPM statistics and higher P-Sharpe ratios.     

人力资源管理强度的研究回顾及在中国情境下的理论框架建构

人力资源管理强度能够从整体上反映企业人力资源管理的效果,在组织管理实践中具有重要的指导作用.但以往关于人力资源管理强度的探讨主要集中于西方情境,这极大地限制了其在中国情境下的发展.因此,本文立足于中国情境,在对现有人力资源管理强度进行理论回顾的基础上,构建了中国情境下人力资源管理强度的研究框架,并从维度、测量与实证研究三个方面进行了未来展望.     

洪口水电站坝基工程地质研究

通过对洪口水电站坝基工程地质条件分析,根据流纹岩岩体硬、脆、碎的特点和物理力学特性,进行工程地质研究,充分利用弱风化流纹岩作为大坝基础,对坝基稳定分析计算,提高了建基面,提出合理处理方式,减少工程量和节省工程投资。     

Together alone: a group-based polarization measurement

Quality & Quantity - The growing polarization of our societies and economies has been extensively studied in various disciplines and is subject to public controversy. Yet, measuring...     

像绅士那样品酒

好酒,自然是由优良葡萄品种酿造而成的,其各种成分和结构均衡协调,香气和风味饱满、丰富、怡人、悠长,不仅能反映葡萄品种的典型特征,更反映葡萄产地的风土和工艺.     

A comparative performance of conventional and Islamic unit trusts: Market timing and persistence evidence

It is expected that the returns and resistance of Islamic mutual funds will be different from conventional mutual funds as the former have limited choices for portfolio diversification. This article analyses the performance of conventional and Islamic unit trusts for the period February 1995 to July 2012 in the Malaysian market, one of the most developed Islamic mutual fund markets. The performance analysis is based on four parameters: (i) risk-adjusted returns of unit trusts; (ii) market timing abilities; (iii) selection performance; and (iv) persistence. The results of this study suggest that the returns of both conventional and Islamic unit trusts have outperformed the market throughout the sample period. The results for market timing and selectivity are mostly the same for both categories of funds. However, Islamic unit trusts seem to have better resistance to market downturn than conventional unit trusts. The results of this research can be used by investors to identify funds or create portfolios that are more suitable for a recessionary scenario and for fund managers to better manage their portfolio performance during times when markets are likely to fall. The findings in this article are highly relevant for policymakers, investors and fund managers to determine policy matters, deciding on investment and marketing strategy for Islamic mutual funds.