INTERNATIONAL MIGRATION: A CASE AGAINST BUILDING EVER‐HIGHER FENCES

International migration, seen as a powerful force of truly global character that is shaping today's socio‐economic reality, is a highly controversial and politicised issue. This paper explores its ramifications in the context of a growing backlash against immigration across the rich world. Specifically, it argues that the free flow of people – like the free movement of goods and capital – is beneficial to developed and developing economies alike and, in doing so, shows how migration produces win–win outcomes. Thus the study, while admitting that inflows of foreign‐born workers pose challenges and entail trade‐offs, makes a case for the liberalisation of immigration policies. The paper deepens our understanding of the issues at hand and constitutes a voice in favour of liberal‐policy choices.     

断面法储量计算在某金矿的应用分析

文章以断面法在胶东某金矿的应用为例,对断面法计算储量进行了详细的介绍。实例说明断面法是一种应用比较方便的储量计算方法,也能保证计算精度。分析总结断面法的优缺点,并从理论上分析了储量计算误差来源及储量计算的精度。     

新城金矿采场支护参数设计

结合本矿的开采技术条件,拟选用砂浆锚索进行预加固。该支护方式能通过砂浆、杆体把岩体连成一体,从而提高了顶板的稳定性,可以有效的防治冒落。被加固矿岩与钢绞线通过水泥砂浆结合成稳固的整体,借助杆体的悬吊作用,来提高采场顶板的岩体稳定性,从而为回采提供安全的作业环境。     

Raising the bar (5)

Raising the bar (5). Spatial Economic Analysis. This editorial summarizes and comments on the papers published in this issue 12(1) so as to raise the bar in applied spatial economic research and highlight new trends. The first paper examines the impact of the level of education on the decision to migrate and finds that it is approximately twice as large if both variables are modelled simultaneously. The second paper is one of the first papers to introduce a spatial component to models of international environmental agreements and to develop an exciting overlap with New Economic Geography. The third paper provides a tool, applied to Beijing, with which urban economic planners can investigate the role of variation and selection mechanisms in cluster development and identify possible paths of growth. The fourth paper contributes to the existing literature on retail geography by examining the role of consumption possibilities as an urban amenity. The fifth paper develops a Bayesian estimator of a linear regression model with spatial lags among the dependent variable, the explanatory variables and the disturbances. Finally, the sixth paper develops a semi-parametric generalized method of moments (GMM) estimator for a spatial autoregressive model with space-varying coefficients of the explanatory variables and a spatial autoregressive coefficient common to all units.     

用PERT法求解不确定网络中活动时间参数的改进研究

基于计划评审技术(PERT)中β分布的假设,阐述了常规三时估计方法的不足,提出了相应解决对策,即采用限定概率三时估计法分别建立了β分布和Gamma分布拟合方差最小模型,用微粒群算法求解模型,并且将求解结果与常规三时估计方法进行了对比研究。实例证实,对于不同类型的活动,可以选择合理的分布类型并利用限定概率三时估计法,对各个活动的持续时间服从的分布密度函数进行拟合,从而提高PERT的精度和效率。     

外出务工对流出地家庭生计策略的影响——来自西部山区的证据

本文首先基于可持续生计框架,引入劳动力迁移的视角,之后改进农户模型以分析劳动力外出务工对流出地家庭生计策略的影响机理,并利用陕西秦岭北麓地区1074户的调查数据进行验证。结果发现:外地打工虽然有利于家庭的资本积累,但会阻碍流出地非农生计活动的参与和劳动力供给;本地打工在促进资本积累的同时,对参与林(经济)作物种植、养殖和自营等生计活动有显著的促进作用,但过多的劳动力外出务工仍然会减少本地其它活动的收入水平。     

Emigration,wage differentials and brain drain: the case of Suriname

In this article, we examine two hypotheses concerning emigration. The first hypothesis is that emigration is positively correlated with wage differentials. The second hypothesis concerns a positive correlation between emigration and higher education in the sending country (the so-called brain gain hypothesis). We analyse unique time-series data for Suriname for the period 1972–2009, for which we fit error correction models to disentangle short-run from long-run effects. We document moderate support for the first hypothesis, but we find strong support for the brain drain (and not brain gain) hypothesis. We conclude with implications of our findings for Suriname.     

Migration and Americanization: The special case of Belgian economics*

One of the distinguishing features of Belgian economics is that, from the early 1920s, so many of Belgium's best economists pursued postgraduate studies at top American universities, a case of ‘temporary’ migration. This was made possible by the fellowships granted by the Commission for Relief in Belgium, a legacy of the First World War. After a stay in the US of a few years, most returned to Belgium. However, they maintained strong links with the US. Also, they tried to recreate in Belgium the most valuable elements of their American experience. It would lead to a strong and early Americanization of Belgian economics. Moreover, they were at the forefront of several initiatives to organize economics on a European scale, such as the European Economic Review and the European Economic Association.     

Trade liberalization,technology, relative factor supplies and the relative wage: evidence from the South

There is much controversy about the role that trade liberalization, technological change and relative factor supplies have played in bringing about changes in the relative wage of the unskilled workers. Much of the empirical work on this issue has focused on the industrial countries and paid little attention to developing countries. To fill this gap, this study develops a special data set to examine the relative wage behaviour of a large number of developing countries. An empirical model based on the theory is used to test different explanations of the relative wage change. As predicted by the technology explanation, the empirical analysis in the study finds a significant negative link between the relative wage of unskilled workers and the technology index. The analysis, however, does not find a significant role for labour supplies or trade liberalization in determining the relative wage of unskilled–skilled workers.