早晚航班对飞行员疲劳程度的影响

航空公司为了提高飞机利用率,导致早晚班的比重明显增加.由于飞行员生物节律的改变,致使其疲劳程度加深.为了保证飞行安全,减缓飞行疲劳,合理排班,需要对执行早晚班的飞行员的疲劳系数进行研究.通过对20名飞行员以及10名飞行学员进行电话访谈,了解到他们早晚班的疲劳程度,进而改进西南航空局可用机组疲劳系数的计算公式,优化了每名飞行员早晚班疲劳系数的计算公式.     

Hi-tech start-ups: legitimacy challenges and funding dynamics

Studies on the legitimacy challenges faced by hi-tech start-ups are still scarce, leaving room for research, and policymaking debate. Legitimacy issues may become difficult to face for hi-tech firms in comparison with other start-ups, because they work in an extreme environment where the technological challenges are at the edge of the scientific possibility. The paper proposes a conceptual model to grasp the relevance of three legitimacy drivers of the hi-tech start-ups for investment decisions. We investigated the ability of 30 hi-tech start-up firms to obtain financial resources from the US investors, employing a set-theoretic approach and carried out fuzzy-set Qualitative Comparative Analysis. Our findings clarify that the funding decisions of US investors are driven by the location of headquarter and R&D of hi-tech start-ups and by the educational experience of the founders. Our study has significant theoretical, practical, and policymaking implications.     

A hybrid information approach to predict corporate credit risk

This study proposes a hybrid information approach to predict corporate credit risk. In contrast to the previous literature that debates which credit risk model is the best, we pool information from a diverse set of structural and reduced‐form models to produce a model combination based on credit risk prediction. Compared with each single model, the pooled strategies yield consistently lower average risk prediction errors over time. We also find that while the reduced‐form models contribute more in the pooled strategies for speculative‐grade names and longer maturities, the structural models have higher weights for shorter maturities and investment grade names.     

The Impact of Employment on Parental Coresidence

We examine the extent to which parents use housing and shared living arrangements as a form of risk‐sharing for their adult children, using detailed data on children and parents in the Health and Retirement Study for 1998–2012. On average, a young man moving from full‐time to nonemployment raises the likelihood of coresiding with a parent by 1.5 percentage points; moving from full‐time employment to being part‐time employed raises the likelihood of coresiding with a parent by 2 percentage points. The implied elasticity of parental coresidence with respect to the son's income is ‐1.1; for daughters, the elasticity is ‐0.5.     

Mobile learning adoption for tourism education in a developing country

Since developing countries are gradually introducing mobile-based tourism education, it is a growing demand to understand the students’ intention to adopt mobile learning. The study used partial least squares-based structural equation modelling to analyse survey data from 176 questionnaires at three tourism education institutes in Bangladesh. The study contributes to the theory of planned behaviour by examining the antecedent impact of innovativeness and moderating effect of self-efficacy. Results confirmed innovativeness as a significant antecedent on the attitude–intention relationship; however, the moderating effect of self-efficacy has not been supported. The study has marketing implications for tourism education institutes and government bodies.     

债务违约、社会责任与政府支持

转型期中国，地方国有企业作为地区经济发展的一股中坚力量，当其发生债务违约时，作为实际控制人的地方政府究竟是否愿意提供支持，会优先选择哪些企业提供支持，政府的支持行为是否会影响到信贷资源的配置效率呢?为得到验证，文章选取2007-2016年沪深A股地方国有上市企业作为研究样本，实证分析了地方国企发生债务违约后，地方政府的支持行为及其对信贷资源配置效率的影响。研究结论表明：第一，地方国企发生债务违约后，地方政府会提供更多的"支持"，且支持额度与债务违约额呈显著正相关关系；第二，债务违约前，承担了更多社会责任（环保投资、捐赠以及就业等）的地方国企，在债务违约后可相应地获得更多的地方政府支持；第三，违约企业，尤其是得到更多政府支持的违约企业可获得更多的信贷资源，而其经营业绩却往往更差。由此表明政府干预一定程度上降低了信贷资源配置效率。     

The Gravity of Intermediate Goods

Review of Industrial Organization - One of the puzzles of the gravity literature is the persistent effect of distance on trade flows, despite the dramatic fall in trade costs during the last few...     

农作物面积抽样单元空间变异性及其对抽样外推效率的影响

［目的］联合遥感和传统抽样方法的空间抽样技术是进行大区域农作物面积监测的有效手段。但传统抽样要求抽样单元间相互独立，并未考虑到区域农作物空间变异性的存在对农作物面积空间抽样效率是否有影响及其影响程度如何，从而限制了农作物面积监测的效率和精度。［方法］文章以吉林省德惠市为研究区，利用变异函数分别对10种抽样单元尺度内玉米和水稻种植面积的空间变异性进行定量评价。选择3种空间抽样方案（简单随机抽样、系统抽样、分层抽样），分别计算不同空间变异程度下的样本容量（n）、抽样相对误差（Re）和总体总值估计量的变异系数（CV（Y︿））作为空间抽样效率的评价指标，定量分析空间变异性对农作物面积空间抽样效率的影响，提出适宜空间变异农作物的空间抽样优化方案。［结果］(1)玉米和水稻面积的空间变异性（反映为基台值C0+C）均随着抽样单元尺度的增加逐渐而减小，其中500m×500m和2 500m×2 500m抽样单元尺度下农作物面积的空间自相关程度相对最小。(2)相同抽样比下，农作物面积在3种抽样方法下的相对误差和变异系数均随着空间变异性的减小（抽样单元尺度增加）逐渐增大，其中玉米和水稻在分层抽样条件下的相对误差和变异系数具有相对最小值，分别限制在10%和20%以内，其次为系统抽样（Re<40%，CV（Y︿）<88%）和简单随机抽样（Re<50%，CV（Y︿）<75%）。 在抽样方法被选定的情况下，两种农作物的分层抽样相对误差变化率随着抽样比的增加迅速降低，当抽样比增至5%时，其相对误差和变异系数的变化率基本趋于稳定，继续增加抽样比来提高抽样精度的效果甚微。 在3 500m×3 500m抽样单元尺度内，按5%抽样比确定的样本容量对玉米和水稻面积进行分层抽样时，可达到95%的抽样精度（Re<5%）。 综合农作物在不同抽样单元尺度下的空间变异特征和空间抽样效率，基于2 500m×2 500m的抽样单元尺度和5%抽样比进行分层抽样的空间变异性农作物空间抽样方案是一种高精度、低成本、代表性强的空间抽样方案。［结论］该研究为区域农作物面积抽样调查方法的改善和抽样效率的提高提供技术支持和参考依据。     

A tale of two Italies: ‘access-orders’ and the Italian regional divide

ABSTRACT

This paper uses the ‘access orders’ paradigm developed by North, Wallis, and Weingast [(2009). Violence and social order: A conceptual framework for interpreting recorded human history. Cambridge: Cambridge University Press] to analyse the case of the Italian North–South economic divide. In line with their framework, we collect and discuss several social and political indicators over the long-run, at the regional level. Firstly we looked at data on the pre-conditions for the establishment of an open-access order, such as murders per capita (a proxy for control over violence), voting turnout and referendums participation (proxies for political legitimacy), and the impersonality of exchange. We then showed evidence of different access orders in the North and in the South, using the information on human capital formation, women participation in the labour market, and referendum results. On the basis of this evidence, we argue that, despite being part of the same State and subject to the same formal institutions, the North of the country progressively developed into an open-access order, while the South remained a form of limited access order.

Institutional differences are linked to specific aspects of the economic performance of the two areas, thus the ‘access order’ paradigm appears to be an effective conceptual scheme to explain the North–South economic divide.