1,642 research outputs found

    An ALM Model for Pension Funds using Integrated Chance Constraints

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    We discuss integrated chance constraints in their role of short-term risk constraints in a strategic ALM model for Dutch pension funds. The problem is set up as a multistage recourse model, with special attention for modeling the guidelines proposed by the regulating authority for Dutch pension funds. The paper concludes with a numerical illustration of the importance of such short-term risk constraints.

    Optimizing electricity distribution using two-stage integer recourse models

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    We consider two planning problems faced by an electricity distributor. Electricity can be ob-tained both from power plants and small generators such as hospitals and greenhouses, whereas the future demand for electricity is uncertain. The price of electricity obtained from the power plants depends on quota that are to be determined in a yearly contract, whereas the (given) contracts with small generators contain various constraints on switching them on or off.

    Fast heuristics for a dynamic paratransit problem

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    In a previous paper we developed a non-standard two-stage recourse model for the dynamic day-ahead paratransit planning problem. Two heuristics, which are frequently applied in the recourse model, contain many details which leads to large CPU times to solve instances of relatively small size. In this paper we simplify both heuristics to decrease CPU time considerably while maintaining the quality of the obtained solutions as much as possible. Numerical experiments on (semi-)realistic instances, inspired by practice, show that our recourse model with fast heuristics provides acceptable solutions within reasonable time.

    Modulation of Functional Activities of Chicken Heterophils by Recombinant Chicken IFN-γ

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    The objective of the present studies was to examine the in vitro effects of recombinant chicken interferon-γ (rChIFN-γ) on shape change, phagocytosis, and the oxidative/nonoxidative killing activities of day-old chicken heterophils. Heterophils (4 × 106/ml) were incubated with various concentrations of recombinant ChIFN-γ from both Escherichia coli and transfected Cos cells for 2 h at 39°C. The incubation of the neonatal heterophils with rChIFN-γ resulted in significantly greater numbers of cells with membrane shape change when compared with the mock-treated heterophils. Both Cos cell-derived and E. coli-derived ChIFN-γ significantly increased (p < 0.01) the phagocytosis of opsonized or nonopsonized Salmonella enteritidis by the neonatal heterophils in a concentration-dependent manner. Incubation with ChIFN-γ induced no direct stimulation of the respiratory burst by the chicken heterophils but did prime the heterophils for a significantly strengthened respiratory burst to subsequent stimulation with opsonized zymosan (OZ). Lastly, incubation of the heterophils with ChIFN-γ primed the cells for a significant increase in the release of β-D-glucuronidase following stimulation with OZ. These results show that neonatal avian heterophils can respond to cytokine modulation with enhanced functional competence, suggesting that ChIFN-γ can enhance the immune competence of the innate defenses of chickens during the first week of life

    An ALM Model for Pension Funds using Integrated Chance Constraints

    Get PDF
    We discuss integrated chance constraints in their role of short-term risk constraints in a strategic ALM model for Dutch pension funds. The problem is set up as a multistage recourse model, with special attention for modeling the guidelines proposed by the regulating authority for Dutch pension funds. The paper concludes with a numerical illustration of the importance of such short-term risk constraints

    Poverty Alleviation through Sustainable Strategic Business Models: Essays on Poverty Alleviation as a Business Strategy

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    How can the private sector serve the unmet needs of the world’s poor while, at the same time, attracting new business opportunities and advancing the standard of living of those living in poverty? One approach to this, known as the base-of the-pyramid, is for the private sector to develop towards including the poor as both producers and consumers. In this thesis we focus on some critical questions in base-of-the-pyramid research. In cooperation with NGOs, development organizations and micro finance institutions, we collected a unique dataset of 143 firms operating in base-of-the-pyramid markets in a total of 105 countries. Their focal group of customers, employees, suppliers, and/or distributors have an average daily purchasing power of $2 or less. Building upon this dataset, we develop an empirically derived classification of business challenges for firms at the base-of-the-pyramid, and examine differences with high-income markets. We also extend and test the central postulate that embedding social and environmental value in a firm’s business model drives a firm’s financial performance at the base-of-the-pyramid. Lastly, we build a management support model, which can be used to develop profitable pro-poor business models. We provide managers and entrepreneurs with the questions to ask, the framework to help formulate answers to these questions, and the qualities to search for in the answers. To this end, we clarify and conceptually advance the strategic business model concept, which provides the multi-theoretical approach necessary for disruptive innovation and augments our understanding of competitive advantage

    A dynamic day-ahead paratransit planning problem

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    Fast heuristics for a dynamic paratransit problem

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