A quintessential immigrant niche? The non-case of immigrants in the Dutch construction industry

Students of immigrant entrepreneurship show a distinct preference for ethnic concentrations. They focus on small entrepreneurship in sectors with large concentrations of immigrant businesses or on ethnic commercial precincts. This preference stems from practical and theoretical considerations. It seems that the study of such concentrations, or niches, is essential to the theoretical understanding of the structural determinants of small entrepreneurship and the processes of economic incorporation of immigrants. This paper challenges this orthodoxy. It argues that it is important to assess the factors and processes that positively and negatively affect the formation of niches. This argument is corroborated by an analysis of the construction industry in the Netherlands. According to Waldinger (1995: 577), ‘construction represents the quintessential ethnic niche’, but immigrants in the Netherlands did not carve out a niche. This exceptional situation can be attributed to a sector-specific configuration of social, economic and institutional processes.     

关于我国农业可持续发展的若干思考

农业可持续发展的理念是对传统的农业现代化思路的否定，它要求逐步改变形成于计划经济时代的旧的生产经营体制，这是一项长期，杂复和艰巨的任务，我们必须为此作不懈的努力。     

构建“三个代表”重要思想“三进”的运作体系

党的十六大把“三个代表”重要思想写进党章,作为党必须长期坚持的指导思想。把“三个代表”重要思想与邓小平理论同时“进教材、进课堂、进学生头脑”,是新的形势向高校提出的战略任务。     

Optimal dividend policy and growth option

We analyse the interaction between the dividend policy and the decision on investment in a growth opportunity of a liquidity constrained firm. This leads us to study a mixed singular control/optimal stopping problem for a diffusion that we solve quasi-explicitly by establishing a connection with an optimal stopping problem. We characterize situations where it is optimal to postpone the distribution of dividends in order to invest at a subsequent date in the growth opportunity. We show that uncertainty and liquidity shocks have an ambiguous effect on the investment decision.      

A DC programming heuristic applied to the logistics network design problem

This paper proposes a new heuristic method for the logistics network design and planning problem based on linear relaxation and DC (difference of convex functions) programming. We consider a multi-period, multi-echelon, multi-commodity and multi-product problem defined as a large scale mixed integer linear programming (MILP) model. The method is experimented on data sets of various size. The numerical results validate the efficiency of the heuristic for instances with up to several dozens facilities, 18 products and 270 retailers.     

21世纪我国物流业发展面临的机遇与挑战浅析

我国物流业的发展经历了从无到有、从传统的简单物流模式发展到现代新型的物流模式阶段,走过了一条曲折的道路。尤其是进入21世纪以来,随着我国加入WTO协定,企业所面临的市场竞争是前所未有的,机遇与挑战并存。为参与国际竞争,企业必须通过降低成本、扩大销售、提高自身核心竞争力等一系列的措施和方法来应对,以便在国际市场激烈的竞争环境中取得优势,占有一席之地。因此,必须积极把握机遇,迎接挑战。     

Optimization of postal express line network under mixed driving pattern of trucks

Details about the movement of trucks on postal express lines are investigated to improve the performances of mail distribution. A mixed driving pattern of trucks is introduced to minimize the transportation cost of a postal express line network with a service level requirement. We formulate this problem as a mixed p meeting depots location with shipment scheduling problem and build a MINLP model. A two-level tabu search procedure based on shipment grouping method is developed. Through a series of computational experiments and sensitivity analysis on different instances, some managerial insights of the network under mixed driving pattern are revealed.     

农资连锁经营应急机制下车辆调度研究

连锁经营,作为农资流通领域的新模式,逐步取代了原本散乱的农资零售格局。物流配送活动作为连锁经营理念的核心,是农资连锁经营能够成功运作的关键。但由于农业生产对农资产品的特殊要求,当消费者对农资产品有紧急需求,但就近的连锁店铺不能供货时,会给农业生产带来不利影响。本文引入应急概念,构建了应急车辆调度模型,来实现配送中心对企业配送系统内部各节点的库存的协调,使该连锁店能够快速响应消费者需求。     

有效需求波动、国有商业银行调整刚性与外资银行经营规模的选择

本文建立了一个有效需求水平不确定情况下的两阶段混合寡占博弈模型．前瞻性地讨论了国有商业银行的经营规模表现出调整刚性的情况下，外资银行经营规模的选择、其实际想要吸收的均衡存款量与选定经营规模之间所存在的关系．以及这种关系将会带来怎样的宏观经济与社会福利后果等问题。研究发现：（1）当实际中的有效需求水平越低时，外资银行经营规模的“产能”过剩；（2）当实际中的有效需求水平越高时，外资银行经营规模的“产能”不足。这一发现具有实施促进经济增长、有效控制居民收入差距政策方面的理论含义。     

Mixed up? that’s good for motivation

We show that career concerns can arise in the absence of ex ante uncertainty about an agent’s type, if his unobservable actions influence future productivity. Implementing effort in mixed strategies allows the principal to endogenously introduce uncertainty about the agent’s ex post productivity and generate reputational incentives. Creating such ambiguity can be optimal for the principal, even though this exposes the agent to additional risk and reduces output. This finding for an environment with imperfect commitment contrasts with standard agency models, where implementing mixed strategy actions typically is not optimal if pure strategies can also be implemented.