Moving for a ‘better welfare’? The case of transnational Sudanese families

The burgeoning literature on welfare migration, or on the likelihood of migrants moving to countries with more generous welfare states, yields mixed results. In this article, we aim to disentangle what kinds of considerations underlie the decisions that migrants and their families make to address their social protection needs when they move to certain places. We explain how Sudanese extended families, with members scattered across multiple countries, draw on formal and informal institutions to meet their needs for social protection. Through a transnational approach, we analyse the mechanisms guiding the access, circulation and coordination of resources to cover different but related social protection domains. We contribute to current debates on transnational social protection by drawing on the life stories of members of a Sudanese transnational family and by expanding on the concept of ‘resource environment’. We based this article on 14 months of multi‐sited ethnographic fieldwork with Sudanese migrants and their families in the Netherlands, the UK and Sudan.     

LOT-SIZING IN CAPACITATED MULTI-STAGE SERIAL SYSTEMS

The lot-sizing problem in capacitated multi-stage systems with a serial product structure is addressed. This is a complex optimization problem that is part of the decision set in material requirements planning (MRP) systems. The mathematical model that describes the problem uses the concept of echelon stock and includes lead times. Setup times are taken into account, which implies that the problem of finding a feasible solution is NP-Complete. This paper proposes a heuristic method that provides a production plan in order to minimize inventory, production, and setup costs. The heuristic starts from a solution for the uncapacitated problem, which is given by the sequential application of the Wagner-Whitin algorithm. Feasibility is then attempted by shifting production amounts between periods. Computational tests conducted in 1,800 instances with up to 40 components and 18 periods have shown that feasible solutions were obtained in 83.7% of the instances. For the infeasible instances, on average, the heuristic is able to find solutions with very low capacity excess. The solutions' quality is evaluated through a lower bound provided by Lagrangean relaxation and on average the gap is less than 10%.     

Estimating the Period of a Cyclic Non‐Homogeneous Poisson Process

Abstract. Motivated by applications of Poisson processes for modelling periodic time‐varying phenomena, we study a semi‐parametric estimator of the period of cyclic intensity function of a non‐homogeneous Poisson process. There are no parametric assumptions on the intensity function which is treated as an infinite dimensional nuisance parameter. We propose a new family of estimators for the period of the intensity function, address the identifiability and consistency issues and present simulations which demonstrate good performance of the proposed estimation procedure in practice. We compare our method to competing methods on synthetic data and apply it to a real data set from a call center.     

RENT‐SEEKING AND CAPITAL ACCUMULATION

A general model incorporating rent‐seeking activities in the standard neoclassical model of capital accumulation is presented. The welfare of the representative agent is negatively affected by the efficiency of rent‐seeking activities. Although intuitive, this result is not obvious because long‐run income can be positively affected by more efficient rent‐seeking activities. The model is used to provide explanations for some recent experiences in developing countries, including the relative poor performance of economies that experience a move to a more decentralized system and the observed path of total factor productivity (TFP) in countries like Ireland and Venezuela. (JEL D23, D74, O40, O41, O47)     

CHARACTERIZING ECONOMIC GROWTH PATHS BASED ON NEW STRUCTURAL CHANGE TESTS

One of the prevalent topics in the economic growth literature is the debate between neoclassical, semi‐endogenous, and endogenous growth theories regarding the model that best describes the data. An important part of this discussion can be summarized in three mutually exclusive hypotheses: the “constant trend,” the “level shift,” and the “slope shift” hypotheses. In this article we propose the characterization of a country's economic growth path according to these break hypotheses. We address the problem in two steps. First, the number and timing of trend breaks is determined using new structural change tests that are robust to the presence, or not, of unit roots, surpassing technical and methodological concerns of previous empirical studies. Second, conditional on the estimated number of breaks and break dates, a statistical framework is introduced to test for general linear restrictions on the coefficients of the suggested linear disjoint broken trend model. We further show how the aforementioned hypotheses, regarding the economic growth path, can be analyzed by a test of linear restrictions on the parameters of the breaking trend model. We apply the methodology to historical per capita gross domestic product for an extensive list of countries. The results support the three alternative hypotheses for different sets of countries. (JEL C22, F43, O40)