Estimating gravity equation models in the presence of sample selection and heteroscedasticity

Gravity models are widely used to explain patterns of trade. However, two stylized features of trade data, sample selection and heteroscedasticity challenge the estimation of gravity models. We propose a two-step method of moments (TS-MM) estimator that deals with both issues. The Monte-Carlo experiments show that the TS-MM estimates are resistant to various combinations of sample selection and heteroscedasticity. Moreover, the TS-MM estimator performs reasonably well even when the data generating process deviates from the TS-MM assumptions. We revisit the world trade in 1990 to illustrate the usefulness of the proposed model, with emphasis on the identification of the extensive margin of trade.     

论我国食品安全监管体制的完善

食品安全问题的日益严重,引发国人的极度关心。问题的频发表明我国食品安全监管执法体制还存在不少漏洞。其问题主要是：事前监管缺乏科学性、事中监管缺乏有效性、事后监管缺乏及时性、可追溯性。因此食品安全监管事前必须要建立合理的食品安全标准,严格食品行业准人标准;事中应完善食品生产经营过程监管,提高食品安全检验水平;事后要建立政府问责机制,加大对食品生产者违法行为的惩罚力度,完善社会监督机制。     

Assessing the Reliability of Self‐reported Income Information in Informal Small Business Lending through a Bogus Pipeline Experiment

Coping with asymmetric information plays a major role in successful small business lending. Our purpose is to determine if small business applicants report their income information correctly when requesting a loan. We use a randomised controlled trial bogus pipeline experiment, established during a typical cash‐flow analysis of a bank for small businesses in the Philippines. The bogus pipeline approach is commonly applied in social science and aims to increase the rate of truth telling by informing participants that answers will be verified by a lie detector. The experimental data, which include 243 observations of credit clients that are mainly from the agricultural and food value chain, served to identify asymmetric information. Additionally, debtors’ repayment behaviour for approved loans was observed by the bank. Our results indicate that loan applicants of the treatment group report lower incomes, an effect which is most pronounced in lower income quantile. Our analyses also reveal higher loan delinquencies in the control group.     

Is late really better than never? The farmer welfare effects of pineapple adoption in Ghana

Export agriculture offers potentially high returns to smallholder farmers in developing countries, but also carries substantial market risk. In this article we examine the intertemporal welfare impact of the timing of a farmer's entry into the export pineapple market in southern Ghana. We examine whether farmers who never cultivated pineapple are better or worse off than farmers who decided to adopt pineapple earlier or later relative to their peers and experienced a significant adverse market shock several years prior to our endline survey. We use a two‐stage least squares model to estimate the causal effect of duration of pineapple farming on farmer welfare. Consistent with economic theory, we find that earlier adoption of the new crop brings greater welfare gains than does later uptake. But we find that the gains to later uptake of pineapple—just before the market shock—are small in magnitude, just 0.1 standard deviations of a comprehensive asset index, indicating that the gains to adoption may be precarious and depend on the context, in particular on the severity of prospective market shocks.     

严格导游准入制度与健全导游管理体制的探讨

目前,由于导游准入制度体系存在缺陷,旅游市场管理体制仍待完善,导游整体素质亟待提高等深层次的问题日益凸显。文章主要剖析这一现象的成因,提出严格导游员准入制度,建立健全旅游管理机制及相关法律法规体系,以提高导游整体素质,提升导游服务质量。     

HR managers in five countries: what do they do and why does it matter?

The 1980s saw the need for change in the organizational role of human resource (HR) professionals, from the traditional employee champion and administrative expert to strategic business partner and change agent. The argument posited was that a more challenging environment compels organizations to turn to managing their HRs as a source of competitive advantage and that means an increasing business partnership for HR professionals. However, very few studies examine the execution of these multiple, sometimes contradictory roles, despite the risk that neglecting traditional roles endanger organizational performance in the long term. This five-country comparative study finds that multiple roles are at least moderately executed, and that these HR roles have different impact depending on the aspect of organizational performance. As well, a more challenging environment, defined here as legal constraints and industry challenges, generally does not have a significant moderating effect on the impact of the different HR roles on organizational performance.     

浅谈新形势下的高职院校设备管理工作

从设备的购置、转资、使用、维修和报废等5个环节入手,介绍了新形势下高职院校设备管理工作的一些经验做法,指出了加强设备管理人员培训的重要性。     

Context-Sensitive Access Control Model for Government Services

During the past two decades, e-government information systems have become less paper-based and more computer-based. Those information systems usually take the form of workflow systems. Due to the large social impact of e-government systems, computer security plays a pivotal role in ensuring its efficiency and effectiveness. Access control is one of the key aspects of computer security. Current access control models do not take into account the context of the system and its environment. In this article, we argue that a formal context-sensitive access control model can improve the development of e-government workflow systems and present a particular context-sensitive access control model. The subject of the article is a specification of the context-sensitive access control model for business processes (COBAC). By using a context-sensitive access control, it is possible to define more sophisticated access control policies that cannot be implemented by existing access control models. The COBAC's context is modeled using Web Ontology Language (OWL) in order to provide formal representation of context, rich representation of diverse contextual information, semantic interoperability between various context-aware systems, and a high degree of inference making. The presented model is applicable in different e-government systems, and supports the definition of access control policies for both simple and complex business processes. The model's prototype is verified by a case study on a real e-government business process—the national petty offense trial proceedings.     

Media,Education and Corruption: Investigating the Associations

We study the interactive association of press freedom, access to media and education with a nation's corruption levels. A free press generates unbiased information that greater access to the media helps propagate; and a greater degree of education, in the same context, helps individuals apply that information. This entire process generates a vigilant and corruption‐free economy. It is therefore important to consider these factors in conjunction.