经济增长与不平等对我国农村脱贫时间的影响

选择FGT贫困指数和脱贫时间指数，利用世界银行公布的我国农村贫困线和收入分配分组数据。对比分析了1981年-2005年以来的农村贫困变化趋势。研究发现，农村贫困状况虽然总体上呈缓解趋势，但在脱贫时间指数的构成中，由于不平等所延长的脱贫时间，无论从绝对量还是相对量上都明显提高，这说明收入分配的恶化已经成为反贫困的严重障碍，这种变化趋势值得高度关注。     

Identifying Discretionary Fiscal Policy Reactions with Real‐Time Data

We propose a method of identifying discretionary fiscal policy reactions using real‐time data. Automatic stabilizers should depend on true GDP, while discretionary fiscal policy is contingent on the information that policy makers have in real time. We can compute a real‐time measurement error by comparing the first release of GDP data with later revisions. Discretionary fiscal policy is influenced by this measurement error, whereas automatic fiscal policy is not. We use this identification approach to test the central identifying assumption of Blanchard and Perotti’s (2002) seminal structural vector autoregression (VAR). According to this assumption, fiscal policy makers do not react to GDP developments contemporaneously in a discretionary fashion. We find that government expenditure is adjusted upward if GDP growth in real time is lower than true GDP. This suggests that fiscal policy makers use short‐term funds to buy goods and services in response to their perception of GDP dynamics.     

Do investors actually value sustainability? New evidence from investor reactions to the Dow Jones Sustainability Index (DJSI)

Research Summary: Research exploring investor reactions to sustainability has substantial empirical limitations, which we address with a large‐scale longitudinal financial event study of the first global sustainability index, DJSI World. We examine investor reactions to firms from 27 countries over 17 years that are added, deleted, or continue on the index. We find that once relevant controls and comparisons to observationally equivalent firms beyond the index are included, DJSI events have only limited significance and/or materiality. Nonetheless, investors' valuation of sustainability around the world has evolved over time, involving diminishing reactions to U.S. firms and increasing benefits, particularly of continuation on the index, over time. The study highlights the importance of careful analysis and longitudinal global samples in making inferences about the financial effects of social performance. Managerial Summary: The debate about how investors perceive corporate social responsibility (CSR) predates Milton Friedman's famous statement that the only social responsibility of business is to increase profits. Although extensive research has studied whether sustainability contributes to financial performance, we have yet to understand whether investors believe it pays off. This financial event study of reactions to the addition, continuation, and deletion from DJSI World, the first global sustainability index, shows that investors care little about DJSI announcements. Nonetheless, there is some evidence that global assessments of sustainability are converging and that investors may increasingly be valuing continuation on the DJSI, suggesting that firms may gain at least limited benefits from reliable sustainability activities.     

全货运航空公司单分配严格枢纽航线网络优化设计

针对全货运航空公司，研究其货运航线网络的构建问题。基于单分配严格枢纽航线网络，对传统模型进行改进。以各航线上货物的委托运输成本和自有机队的运输成本，取代传统的单位运输成本和折扣因子，考虑枢纽点的中转成本和载运率对路径选择的影响。结合航空货运夜航的特征考虑各机队夜间可用时间的限制，以总成本最小为目标，构建数学模型，采用LINGO优化软件求解，验证模型的有效性，为全货运航空公司构建货运航线网络提供参考。     

Towards the use of chronological age in research – A cautionary comment

In recent years, this journal published several articles that used chronological age in their models to distinguish customer behavior between younger and older people. While all these articles are in line with the growing importance of age-related research, chronological age is not discriminant when behavior and motivations enter the fray. By taking two recent articles in this journal as examples, this short note calls for a cautious application of chronological age and highlights other age-related constructs for research. The note ends with practical implications and avenues for further research in age-related projects.     

A MILP model for planning the trips of dynamic positioned tankers with variable travel time

The transportation of the crude oil produced in offshore oilfields to onshore terminals is performed by vessels, known as shuttle tankers. Scheduling shuttle-tanker operations entails solving complex problems to ensure a timely offloading of the platforms, taking into account several logistics and inventory constraints. This work proposes a new MILP formulation that advances previous works by considering variable travel time between platforms and terminals. The combination of the MILP formulation with an optimization solver constitutes a decision-support tool to aid engineers reach optimal decisions for a planning horizon. To handle large-scale instances, rolling-horizon and relax-and-fix strategies are proposed.     

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.     

Motivations and Use Context in Mobile Tourism Shopping: Applying Contingency and Task–Technology Fit Theories

Mobile tourism shopping is an emerging market, but there is little theoretically based research on the topic. This study investigates the impact of motivations (value, enjoyment, time saving and mobility) on consumer satisfaction by applying contingency and task–technology fit theories in the mobile tourism shopping context. The results show that value and enjoyment have significant effects on satisfaction. Use context is found to have a full mediating role between time saving and satisfaction as well as between mobility and satisfaction. This study offers theoretical and practical contributions to the tourism literature and mobile tourism industry. Copyright © 2013 John Wiley & Sons, Ltd.     

Waiting time probabilities in the M/G/1 + M queue

We consider an M/G/1 queueing system where the customers may leave the queue if their services do not commence before an exponentially distributed random time. The (conditional) offered waiting time distribution is approximated by a gamma distribution via matching the first and second moments of the actual waiting time. A simulation study is conducted to assess the accuracy of the approximation and it reveals that the approximation performs satisfactorily under general conditions on service time distributions.     

Production technologies in stochastic continuous time models

Properties of dynamic stochastic general equilibrium models can be revealed by either using numerical solutions or qualitative analysis. Very precise and intuition-building results are obtained by working with models which provide closed-form solutions. Closed-form solutions are known for a large class of models some of which, however, have some undesirable features such as potentially negative output. This paper offers closed-form solutions for models which are just as tractable but do not suffer from these shortcomings.