基于TAM的内在感知对影响农户不同节水灌溉技术采用的研究*——以甘肃张掖市为例

[目的]节水灌溉技术采用率低下是制约干旱半干旱地区农业发展的瓶颈,农户作为技术采用的微观主体,如何激励农户采用节水灌溉技术、提高技术采用率是有关实践研究待解决的问题,以往研究大多关注社会因素对技术采用的影响,心理层面即感知影响方面的研究不足。[方法]文章以甘肃省张掖的547份农户调查问卷为例,根据农业技术采用特点对已有技术接受模型(TAM)进行调整与扩展,运用二元Probit回归模型实证分析了内在感知对农户节水灌溉技术采用的影响。[结果]感知有用性、感知易用性是农户对节水灌溉技术认知的内在约束,节水效果、经验交流对农户采用膜下滴灌技术产生显著的正向影响;增产效果、技术有用性对农户采用低压管灌技术产生显著的正向影响;感知社会规范是农户个体社会网络的认知,亲朋使用、邻里使用感知均对农户采用不同节水灌溉技术产生显著的正向影响。农户对节水灌溉技术的采用除受这些因素影响以外,还受到户主性别、年龄、教育、家庭人口总数、健康的影响。[结论]推行技术补贴制度,加大农技推广服务,充分发挥集体行动影响力对提高节水灌溉技术的认知和采用具有重要作用。     

On the investment credentials of Bitcoin: A cross-currency perspective

We examine diversification capabilities of Bitcoin for a global portfolio spread across six asset classes from the standpoint of investors dealing in five major fiat currencies namely US Dollar, Great Britain Pound, Euro, Japanese Yen and Chinese Yuan. Considering the period of prolonged decline in Bitcoin’s value throughout 2018, we employ modified conditional value-at-risk and standard deviation as measures of risk to perform portfolio optimisations across three asset allocation strategies. Results show that portfolios denominated in Japanese Yen, Chinese Yuan and US Dollar account for greater proportion of optimal investment in Bitcoin and exhibit higher improvement in risk-adjusted returns due to investment in Bitcoin. We also perform a comprehensive risk-adjusted evaluation of portfolios with and without Bitcoin to reinforce striking variation in degree of diversification benefits of Bitcoin in a cross-currency context. Taken together, our findings provide insights into sharp disparity in Bitcoin trading volumes across national currencies from a portfolio theory perspective.     

Factors influencing the consumers’ behavioural intention to use online food delivery service: Empirical evidence from Taiwan

Understanding consumer preferences is crucial in helping online food delivery services (OFDS) increase operating revenue and competitiveness while achieving sustainable development. Prior studies on OFDS employed qualitative research and methods for statistical analysis, but few researchers have discussed the importance of the primary factors influencing consumers' selection and intention of OFDS from multiple-attribute decision-making (MADM) perspective. Based on a consumer's perspective, the MADM techniques were utilised in this study to build an assessment model for consumers' selection of OFDS. First, to determine the relative weight of each evaluation criterion and dimension, the analytic hierarchy process (AHP) was utilised. Subsequently, the complex proportional assessment of alternatives (COPRAS) was utilised to analyse the feasible solutions. Lastly, the modified VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR) was employed to discuss the performance gap between each evaluation dimension and criterion. The three methods helped identify the primary evaluation criteria and determine the rankings of feasible solutions and related performance gaps. The methods were used to conduct an empirical analysis of the data. Several conclusions and suggestions have been provided based on the findings. The findings are anticipated to serve as a reference for OFDS operators to learn from, allowing them to better understand consumers' demands and provide better service. Finally, theoretical and managerial implications are explored.     

修正的房价收入比:衡量我国城市房价泡沫水平的更优指标

改革开放以来,我国城镇居民可支配收入连续多年高速增长,本文通过构建一个包含收入增长的模型,估算城镇居民可承受的按揭还款房价收入比极值。在此基础上,考虑到实际购房分为首付和按揭还款两部分,提出了修正的房价收入比这一新指标,用于衡量首付部分或按揭还款部分是否存在泡沫。通过实证检验,发现我国房地产市场的泡沫主要集中在首付部分,且当首付比例超过20%以后,所考察的13个重点城市的房价都存在严重的泡沫。     

香港转基因食品标签制度剖析

转基因食品标签是个有争议的问题。虽然绝大多数香港民众和公益组织赞成强制性标签,香港政府基于商业和经济考虑,采取了自愿性标签制度。业界可自愿在转基因食品包装上增加"含有转基因成分"的正面标签或"不含有转基因成分"的反面标签。这种自愿性标签制度没有重视消费者权利和食品安全,引致消费者和公益组织的批评。     

Antecedents of consumers’ intentions to upgrade their mobile phones

The fourth generation (4G) mobile phone will soon be launched. Marketers need to know which factors determine whether customers choose to upgrade their mobile phones, as this will affect the diffusion of third generation (3G), 4G, and Worldwide Interoperability for Microwave Access phones. This study integrates pre- and post-adoption theories, upgrading, and value-based theory to examine plans to upgrade to a newer model mobile phone among second generation (2G) and 3G mobile phone users. The empirical results show that the technology acceptance model fails to explain consumers’ intentions to upgrade in sequence. Although customers perceived next-generation mobile phones as being easier to use and more useful than their current model phones, this did not directly influence them to upgrade. When users were satisfied with their current model, they were not willing to upgrade to a newer generation model. Moreover, value assessments affect users’ plans to upgrade to next-generation mobile phones.     

FDI知识溢出对区域低碳创新网络效率的门槛效应研究

针对经济全球化趋势和创新驱动发展战略下区域低碳创新网络发展面临的可持续转型增长问题,以及环境规制与低碳创新网络效率的非直接关联特征,通过构建考虑非期望产出的J SBM模型测算低碳创新网络效率,运用核密度函数模型描绘区域低碳创新网络效率的动态演变规律与区域异质性,从环境规制视角构建FDI知识溢出与低碳创新网络效率的非线性面板回归模型,探讨环境规制的门槛效应和时序变化以及FDI知识溢出与低碳创新网络效率的作用机理。研究表明：样本期间区域低碳创新网络效率整体较为收敛,地区差距呈扩大趋势;人力资本和吸收能力因素与低碳创新网络效率显著正相关,政策支持和市场竞争在一定程度上制约低碳创新网络效率提升;加大环境规制强度能够促进FDI知识溢出、提升低碳创新网络效率;门槛效应的时空异质性明显,不同年份同一地区的分布存在较大差异。     

转基因食品强制标识制度在世贸组织框架内的法律分析

鉴于转基因食品可能存在不确定的风险,许多国家都要求对转基因食品进行强制标识。由于欧盟自1998年以来暂停批准转基因农产品在欧盟市场的准入申请,2003年5月,美国、加拿大和阿根廷在世贸组织提起针对欧共体的申诉。在该案的审理过程中,欧盟对转基因食品的强制标识制度也成为一个争议的问题,这给中国政府敲响了警钟。在中国,目前有农业部和卫生部的两个相关管理办法。本文根据世贸组织的相关规则,包括《实施卫生与植物卫生措施协定》、《技术性贸易壁垒协定》以及关贸总协定1994第20条,从实体和程序上对我国现行规定的合法性进行了具体分析,并提出了相应建议,以期为政府相关部门的决策提供参考。     

Predicting Tourists' Intention to Try Local Cuisine Using a Modified Theory of Reasoned Action: The Case of New Orleans

The purpose of the present study was to examine the utility of the modified theory of reasoned action (TRA) in predicting tourists' behavioral intention to try the local cuisine in New Orleans. The results indicated that the proposed model had strong predictive ability regarding tourists' intention to try the local cuisine. Attitude and past behavior were significant predictors of tourists' behavioral intention. In addition, the interdependence between attitudinal and normative components was partly supported. Gender had a significant moderating role in the relationships between attitude/past behavior and behavioral intention to experience the local cuisine. Theoretical and practical implications of the findings are discussed.     

The precautionary principle: an 'unprincipled' approach to biotechnology regulation

A tenet of administrative law, particularly in the United States, is that regulators must base their decisions on 'intelligible principles' to provide consistency, predictability, transparency and accountability. The precautionary principle, which purports to provide a new decision rule for making environmental decisions under conditions of uncertainty, fails to provide such an intelligible principle for making decisions. The precautionary principle is ambiguous on the use of the two major criteria currently used to make environmental decisions - significant risk and cost-benefit balancing - yet offers no new specific decision criteria in their place. The second fundamental problem with the precautionary principle is that it is based on the unsubstantiated premise that the current regulatory system is insufficiently protective. The current system already tends to err on the side of the safety, as it should, but the relevant question is just how precautious should we be? As illustrated by the example of genetically modified organisms, the prudent level of precaution depends on factors such as the magnitude, distribution and uncertainty of risks, the extent of exposure, and the trade-offs and lost benefits in foregoing the risk. These are precisely the factors that are considered under the current risk-based approach, which the precautionary principle seeks to replace.