粮食中镉含量测定方法初探:以石墨炉原子吸收分光光度计法为例

笔者长期从事粮食中镉污染检验工作,大量实践经验表明,虽然原子吸收仪的品牌、型号各不相同,但应用原理、结构大致相同。本文以石墨炉原子吸收分光光度计法对粮食中镉的含量的检测为例进行说明,发现试样前处理、试剂空白、使用试剂、回收实验及在操作过程中的对仪器的处理等对检测结果均会产生直接影响。为确保检测结果准确性,本文对检测过程中影响检测结果的各注意事项进行了分析总结,希望能对从事镉污染检测工作的人员提供理论指导和借鉴。     

Essential equilibria of large generalized games

We characterize the essential stability of games with a continuum of players, where strategy profiles may affect objective functions and admissible strategies. Taking into account the perturbations defined by a continuous mapping from a complete metric space of parameters to the space of continuous games, we prove that essential stability is a generic property and every game has a stable subset of equilibria. These results are extended to discontinuous large generalized games assuming that only payoff functions are subject to perturbations. We apply our results in an electoral game with a continuum of Cournot-Nash equilibria, where the unique essential equilibrium is that only politically engaged players participate in the electoral process. In addition, employing our results for discontinuous games, we determine the stability properties of competitive prices in large economies.     

Global financial crisis and dependence risk analysis of sector portfolios: a vine copula approach

We use regular vine (r-vine), canonical vine (c-vine) and drawable vine (d-vine) copulas to examine the dependence risk characteristics of three 20-stock portfolios from the retail, manufacturing and gold-mining equity sectors of the Australian market in periods before, during and after the 2008–2009 global financial crisis (GFC). Our results indicate that the retail portfolio is less risky than the manufacturing counterpart in the crisis period, while the gold-mining portfolio is less risky than both the retail and manufacturing sector portfolios. Both the retail and gold stocks display a higher propensity to yield positively skewed returns in the crisis periods, contrary to the manufacturing stocks. The r-vine is found to best capture the multivariate dependence structure of the stocks in the retail and gold-mining portfolios, while the d-vine does it for the manufacturing stock portfolio. These findings could be used to develop dependence risk- and investment risk-adjusted strategies for investment, rebalancing and hedging which more adequately account for the downside risk in various market conditions.     

Success factors in a CRM strategy: technology is not all

Organisations today need to create, maintain and reinforce relationships with customers. Customer Relationship Management (CRM) seems to have helped firms to better understand their relationships. However, past studies have looked at technology and customer orientations (COs) as key factors. This paper aims to analyse the simultaneous effect of Market Orientation (MO) (rather than CO), Knowledge Management (KM) and other organisational factors in order to explain how to implement a successful CRM. Findings suggest that MO and KM may influence CRM success. Data also suggest that particular organisational factors such as employees, leadership and specific know-how may be key factors in determining the success of CRM. For efficiency resource management, this paper recommends to focus not as much in technology, but on programmes for selection, training and motivation of employees which may enhance CRM objectives. Companies may also pursue a higher customer value by putting in place and reinforcing KM schemes in specific know-hows about CRM.     

Familiness,business strategy and stakeholder engagement: The internationalisation of Spanish olive oil mills

Based on social capital theory and the family-firm context, this paper studies familiness' composition and the result of the overlap of the family and firm systems, analysing their influence on the internationalisation strategies of family firms. In this relationship, the stakeholder engagement becomes at the same time an antecedent and a result when developing family businesses' strategies, being one of the most relevant the internationalisation strategies. Prior research focused on familiness as the result of proxy variables such as the percentage of ownership and management in family hands, or business size, instead of as psychological variables resulting from shared organisational culture and social interactions. Through a qualitative study based on 12 interviews of general managers and/or export managers of Spanish family olive oil mills, this study asserts that the level of familiness influences internationalisation strategies, the reasons underlying a business becoming international and its commitment to activities abroad being the role of stakeholders crucial in those interactions. The higher the level of familiness, the more likely the family business internationalisation and the higher their levels of international commitment. Additionally, the higher the concern about their stakeholders, the higher their levels of international commitment. The family businesses' concern for their stakeholders and their international commitment share a reciprocal relationship. The results regarding the relevance of familiness as social capital resources in sustaining competitive advantages support the decision to promote, develop and nurture social capital when a family business goes international.     

High‐performance work systems and workplace performance in small,medium‐sized and large firms

This article draws on the Organisational Growth and Development (OGD) life cycle model to explore the relationship between high‐performance work systems (HPWS) and performance in firms of different size, thereby extending understanding of congruence or ‘best fit’ theory within strategic HRM debates. With reference to management control theory, economies of scale and the availability of specialist managerial skills, the article hypothesises that while an HPWS–performance relationship might exist in small, medium‐sized and large firms, the relationship will be stronger in large firms than in both small and medium‐sized firms, and stronger in medium‐sized firms than in small firms. Analysis of data from the British Workplace Employment Relations Survey demonstrates, however, that there is no association between HPWS and workplace performance in medium‐sized firms, in contrast to the positive relationship between HPWS and performance found in large firms and between HPWS and labour productivity in small firms.     

不同产地中试生产葡萄酒中白藜芦醇的含量测定

目的是建立中试生产葡萄酒中白藜芦醇的含量测定方法。方法系采用高效液相色谱法测定了白藜芦醇的含量,C_(18)色谱柱(250 mm×4.6 mm,5μm),流动相为甲醇∶水=40∶60,流速1mL/min,检测波长306 nm,柱温30℃。结果显示白藜芦醇与样品中其他组分分离效果较好,白藜芦醇在0.271 3~4.340 0μg范围具有良好线性关系,相关系数r=0.999 9;平均回收率为94.6%,RSD为1.97%(n=6)。结论为采用此法准确可靠,可用于该葡萄酒的质量控制。     

新形势下工程造价能力指标与课程体系标准研究

针对造价人才的执业环境的改变,分析行业在新形势下对咨询业务的新需求,并根据业务实践总结出BIM、PPP、全过程工程咨询等技术和管理模式的出现对造价人才的需求,在此基础上构建新形势下工程造价人才的能力指标体系,并提出了与能力标准体系呼应的核心课程体系设置思路。     

REPORTING GUIDELINES FOR META-ANALYSIS IN ECONOMICS

Meta-analysis has become the conventional approach to synthesizing the results of empirical economics research. To further improve the transparency and replicability of the reported results and to raise the quality of meta-analyses, the Meta-Analysis of Economics Research Network has updated the reporting guidelines that were published by this Journal in 2013. Future meta-analyses in economics will be expected to follow these updated guidelines or give valid reasons why a meta-analysis should deviate from them.     

The impact of environmental regulation on Chinese spatial development

We examine the relationship between environmental regulation and spatial development in China. Exploiting changes in national pollution standards for three industries, ammonia, paper and cement, we measure the impact of environmental regulation on industry productivity. Our results suggest that national pollution standards do not affect industry productivity, but they reallocate productivity spatially. We show that regulated industries located in developing cities increase their productivity compared to similar industries in other cities. This means that environmental regulation affects the spatial distribution of technology in China and might influence long‐term spatial development by reducing geographical disparities.