液相色谱-串联四级杆质谱方法检测动物源性基质中的β2——受体激动剂

利用安捷伦6410高效液相色谱串联质谱（LC／MS／MS）方法快速、准确地测定多种β2-受体激动剂的残留量。串联质谱在电喷雾（ESI＋）,多反应监测（MRM）模式下,进行质谱定性和定量分析,比液相检测方法灵敏、快速。该方法的定量检测限（LOQ）大多在0．5μg／kg以下,完全可以达到欧盟和日本对β2-受体激动剂残留限量的要求。     

Tradable Discharge Permit System for Water Pollution: Case of the Upper Nanpan River of China

A discharge permit system for water pollution of theupper Nanpan River has been tested since 1992. Thispaper proposed the shift of the current non-tradablepermits to tradable permits to attain the samepollution reduction targets at a lower cost. It wasfound that this river appeared good for trading. Apilot trading program for point sources was thenrecommended to a smaller trading zone. There would beten potential trades for chemical oxygen demanddischarge, gaining an annual cost-saving of ChineseYuan 2.4 million, or saving 18.4% of the total annualcost to attain the reduction target without trading.The marginal pollution reduction cost was estimated atChinese Yuan 959 for one kilogram chemical oxygendemand per day. Meanwhile, `without trading' and `withtrading' scenarios would bring about 900.9 kg/day and51.5 kg/day of redundant reduction respectively. Thenet annual benefit arising from trading, about ChineseYuan 1.6 million, would still be significant. At last,the study recommended that compliance monitoring andexecuting institution requirements be kept in mindwhile designing the program. An information systemneeds to be established to provide potentialparticipants relevant information. The method ofpermit allocation and lifespan of permits should alsobe addressed later.     

Empirical Analyses of Extreme Value Models for the South African Mining Index

While the classical normality assumption is simple to implement, it is well known to underestimate the leptokurtic behaviour demonstrated in most financial data. After examining properties of the Johannesburg Stock Exchange Mining Index returns, we propose two extreme value models to fit its negative tail with a higher degree of accuracy. The generalised extreme value distribution (GEVD) is fitted using the block maxima approach, while the generalised Pareto distribution (GPD) is fitted using the peaks‐over‐threshold method. Numerical assessment of value‐at‐risk (VaR) estimates indicates that both GEVD and GPD increasingly outperform the normal distribution as we move further into the lower tail. In addition, GEVD produces lower estimates relative to that of the historical VaR, and GPD provides slightly more conservative estimates for adequate capitalisation.     

锯末/SBR系统处理屠宰场废水的研究

采用锯末强化SBR工艺处理屠宰场废水进行了研究,考察锯末用量、曝气时间、沉淀时间对处理效果的影响。结果表明:投加锯末可以明显改善污泥性能,提高处理效果。锯末/SBR系统处理屠宰场废水过程中,最佳工艺为w(锯末):w(污泥)为2:10,曝气6h,沉淀40min。在此工艺下,进水COD在486~2546mg/L,BOD5在186-1055mg/L、NH3-N在18.5-32.8mg/L之间变化时,锯末/SBR系统运行稳定,平均去除率分别达94.64%、94.34%、96.72%,比单纯SBR系统分别提高17.08%、12.85%、15.69%。进水COD在486~1459mg/L,BOD5在186-604mg/L、NH3-N在18.5-32.8mg/L时,出水水质可达到《城镇污水处理厂污染物排放标准》(GB18918-2002)一级标准。     

Tax reform in Georgia and the size of the shadow economy

This study applies three different methods widely used in the literature to track changes in shadow economic activity in Georgia following a drastic tax reform in 2005. The first method is a currency demand approach based on macrolevel data. The second and third methods rely on micro level data from household surveys. Overall, we find evidence that the amount of income underreporting decreased in the years following the reform. The biggest change is observed for households headed by a farmer, followed by ‘other’ types of households where the head does not report any working status. Employed and self‐employed households appear very similar before the tax reform and show minimal adjustment in income reporting in the post‐reform period. Results, however, suggest that much of any difference may have come from increased enforcement efforts rather than rate changes.     

信用证风险及对策研究

作为国际贸易的重要结算工具之一,信用证被许多国家所接受和使用,但受国际贸易惯例、国内立法、司法效率、诚信体系等因素尚不完善的影响,使用信用证进行结算仍然存在许多风险。通过分析信用证属性和特点,特别是信用证流转过程中存在的主要风险控制点,从立法、司法、银行和企业四方面提出有针对性的防范措施。     

Life satisfaction and support for tourism development

The purpose of this study is to better understand local residents’ support for tourism development by exploring residents’ perceived value of tourism development, life domain satisfaction (material/non-material), and overall quality of life in their community. The study provides the theoretical and empirical evidence of the relationships among those constructs. Using a sample of residents from five different tourism destinations, the results of a structural equation modeling approach indicated that residents’ perceived value of tourism development positively affects non-material and material life domain satisfaction; thereby, it contributes to overall quality of life. Finally, overall quality of life is an effective predictor of support for further tourism development.     

Structural embeddedness and position: evidences from affiliation of patent with technological classifications

This paper contributes to the empirical identification of the structural positions in network through an exploration of the interactions between R&D activities (patents) and technological areas of patents (technological classifications). Affiliation network analysis was conducted to study the affiliation between patents and technological classifications. We identified some key patents and explored the differentiated positions of the core and periphery. The results of network analysis was further verified by statistical analysis. We found that the impacts of the centralities in position were significant. Technological implications and foresights are discussed in the conclusion.     

Trust-building processes in tourist coopetition: The case of a Polish region

This study examines the role of trust in establishing collaboration between two individual competing tourism firms. The study contributes to the existing body of knowledge by investigating how various trust-building processes influence dyadic coopetition in five municipalities in Poland. The literature suggests eight different trust-building mechanisms at various levels of analysis and collaborative endeavors. Our results indicate four processes important to start dyadic coopetition, which are based on: calculation, emotional bond, reputation and embeddedness in social networks. Our findings also show that if trust based on calculation is not reported, then even several trust-building processes combined do not lead to coopetition. Moreover, trust does not appear as a homogenous concept, and different trust-building processes do generate different effects. The results show that trust may play both positive and negative roles in coopetition formation.     

基于B／S结构的港口物资采购管理网上报价的研究

基于B／S结构的物资管理系统网上报价功能不仅实现了供应商供货信息的统一管理，同时具有经济性高、保密性好、易于维护、方便使用和易于扩大业务范围的优点。