A network approach to modeling the multi-echelon spare-part inventory system with backorders and interval-valued demand

A multi-echelon inventory system implies the existence of a hierarchy of stocking locations, and the dependence and interaction between them. We consider a multi-echelon, spare-part inventory management problem with outsourcing and backordering. The problem is characterized by deterministic repair time/cost, and supply and demand that lie within prescribed intervals and that vary over time. The objective is to minimize the total inventory and transportation costs. We develop a network model for problem analysis and present a network flow algorithm for solving the problem. We prove that the Wagner-Whitin property, known for the lot-sizing problem, can be extended to the spare-part inventory management problem under study.     

Normativa de empleo,teoría de juegos y representación laboral insuficiente en las economías liberales

Se analiza el impacto de la normativa europea de información y consulta en los niveles de representación de los trabajadores en dos economías liberales (Irlanda y Reino Unido) a partir de tres postulados teóricos y del dilema del prisionero de la teoría de juegos. Sobre la base de datos cualitativos de 16 empresas recabados mediante entrevistas, los autores evalúan los postulados y explican por qué las normas nacionales de transposición son ineficaces para promover la cooperación en beneficio mutuo en economías liberales, aportando así un modelo teórico a las investigaciones previas sobre el tema, fundamentalmente empíricas.     

Saltatory Ontogeny and the Life-History Model: Neglected Processes and Patterns of Evolution

A single cell – an egg – cannot be in the same stabilized state as a differentiated multicellular embryo or reproducing adult. The entire ontogeny must, therefore, consist of a sequence of stabilized states. Ontogeny of a phenotype cannot progress gradually but is a saltatory homeorhetic system, proceeding via natural thresholds from one self organized state to the next, hierarchically ever more complex and specialized. The natural boundaries of ontogeny – the far-from-stabilized thresholds – represent also states when changes can be easiest inserted or induced, and especially in the early ontogeny, from the intervals where evolution (change) can occur. As a result, ontogeny can also be divided into distinct life-history intervals called periods, be it embryo, larva (infant, pup), juvenile, adult and senescence, each divided in turn into phases, and each of these into natural steps. It is left to the imagination of scholars in social sciences to find parallels of saltation in economics and history.     

Investor reaction to women directors

Existing studies on women directorships present equivocal results on the association between appointing women directors and firm performance. These studies tend to focus on western countries and largely ignore investors' reactions to such appointments. This paper applies the financial event study method and finds that investors generally respond positively to the appointment of women directors in Singaporean firms. Regression analyses also reveal that investors are most receptive when the women are independent directors and are least receptive when the directors assume the CEO role. This study not only tests the theory of gender diversity in an Asian context but also examines whether investors react systematically to the different positions that women directors hold on corporate boards, a question that has received little attention in prior studies.     

Health Care Matters: Supply Chains In and Of the Health Sector

Providing health care involves a complex enterprise, and the trade‐off between quality and cost has been particularly stark compared to other industries. However, a recent focus on health sector supply networks is now producing significant innovations and improvements. This Special Topic Forum illustrates for the academic and practitioner community how health care supply chain research can benefit from our evolving understanding of supply chains and help push that understanding even further. We classify health care supply chain research into two broad categories—supply chain in health care and supply chain of health care—to set an agenda for future research.     

Housing demand in Russia: Rationing and reform1

In a number of articles Alexeev (1988a) and (1988b) shows that in the former Soviet Union the administrative rationing of housing was partially replaced by market forces acting through the second economy. This paper uses a much richer dataset to update his analysis for Russia to consider housing demand in 1992, the last year of the administrative allocation system. Almost immediately after the survey used for this analysis Russia began to privatize the housing stock as part of its movement towards a market economy. The questions we ask are: Were households really able to beat the system, as argued by Alexeev and, if so, were they still able to do so in 1992? Our answer to the second question is that in 1992 households were not able to beat the system. Income had no observable effect on housing demand. Furthermore, we do not think that the difference in our empirical results and Alexeev's is due only to the broader economic changes that occurred since his estimation or the richer dataset available to us. Indeed, our answer to the first question is that there are good reasons for arguing that Alexeev's estimates of the income elasticity of housing demand are biased upwards.