INNOVATION THROUGH (INTERNATIONAL) FOOD SUPPLY CHAIN DEVELOPMENT: A RESEARCH AGENDA

This paper presents a research agenda on innovation through (international) food supply chains and networks in developing countries. It derives major topics from a multi-perspective view on international food chains (economic, technology, social/legal and environment) and from different theoretical streams dealing with chains and networks (Supply Chain Management, Industrial Organization theory and Network Theory). Three agri-supply chain projects in developing countries (Thailand, South-Africa, Ghana) are analyzed to identify focus areas in supply chain development projects and important gaps. These projects were collaborative actions between companies and research institutes to initiate international supply chain development.Industrial Organization,

Dynamic Duopoly with Intertemporal Capacity Constraints

We analyze strategic firm behavior in settings where the production stage is followed by several periods during which only sales take place. We analyze the dynamics of the market structure, the development of prices and sales over time, and the implications for profits and consumer surplus. Two specific settings are analyzed. In the first, a firm can commit up-front to a sales strategy that does not depend on the actual sales of its competitor. In this case there is a unique Nash equilibrium and price increases over time. In the second setting,there is no commitment and firms can adjust their sales in response to observed supply of their competitor in the previous period. It is shown that in this case a subgame perfect Nash equilibrium does not always exist. Equilibria can have surprising features. For some parameter constellations, price may decrease over time. It is also possible that the firm increases its pro�t by destroying some of its production. When firms have equal size, the equilibrium outcome is the same in both the commitment and the non-commitment setting. In general, the setting without commitment is bene�cial to the larger firm, whereas the setting with commitment leads to higher pro�ts for the smaller firm.mathematical economics;

Diagonals of rational functions and selected differential Galois groups

International audienceWe recall that diagonals of rational functions naturally occur in lattice statistical mechanics and enumerative combinatorics. In all the examples emerging from physics, the minimal linear differential operators annihilating these diagonals of rational functions have been shown to actually possess orthogonal or symplectic differential Galois groups. In order to understand the emergence of such orthogonal or symplectic groups, we analyze exhaustively three sets of diagonals of rational functions, corresponding respectively to rational functions of three variables, four variables and six variables. We impose the constraints that the degree of the denominators in each variable is at most one, and the coefficients of the monomials are 0 or $\;\pm 1,$ so that the analysis can be exhaustive. We find the minimal linear differential operators annihilating the diagonals of these rational functions of three, four, five and six variables. We find that, even for these sets of examples which, at first sight, have no relation with physics, their differential Galois groups are always orthogonal or symplectic groups. We discuss the conditions on the rational functions such that the operators annihilating their diagonals do not correspond to orthogonal or symplectic differential Galois groups, but rather to generic special linear groups

Preference polymorphism for coloration but no speciation in a population of Lake Victoria cichlids

Female mating preference based on male nuptial coloration has been suggested to be an important source of diversifying selection in the radiation of Lake Victoria cichlid fish. Initial variation in female preference is a prerequisite for diversifying selection; however, it is rarely studied in natural populations. In clear water areas of Lake Victoria, the sibling species Pundamilia pundamilia with blue males and Pundamilia nyererei with red males coexist, intermediate phenotypes are rare, and most females have species-assortative mating preferences. Here, we study a population of Pundamilia that inhabits turbid water where male coloration is variable from reddish to blue with most males intermediate. We investigated male phenotype distribution and female mating preferences. Male phenotype was unimodally distributed with a mode on intermediate color in 1 year and more blue-shifted in 2 other years. In mate choice experiments with females of the turbid water population and males from a clearer water population, we found females with a significant and consistent preference for P. pundamilia (blue) males, females with such preferences for P. nyererei (red) males, and many females without a preference. Hence, female mating preferences in this population could cause disruptive selection on male coloration that is probably constrained by the low signal transduction of the turbid water environment. We suggest that if environmental signal transduction was improved and the preference/color polymorphism was stabilized by negative frequency-dependent selection, divergent sexual selection might separate the 2 morphs into reproductively isolated species resembling the clear water species P. pundamilia and P. nyerere

Business Process Modelling in Demand‐Driven Agri‐Food Supply Chains

Agri ‐food companies increasingly participate in demand‐driven supply chains that are able to adapt flexibly to changes in the marketplace. The objective of this presentation is to discuss a process modelling framework, which enhances the interoperability and agility of information systems as required in such dynamic supply chains. The designed framework consists of two parts: an object system definition and a modelling toolbox. The object system definition provides a conceptual definition of business process in demand‐driven supply chains from a systems perspective. It includes an application of the Viable Systems Model of Stafford Beer to supply chains, and classifications of business processes, control systems and coordination mechanisms. The modelling toolbox builds on the terminology and process definitions of SCOR and identifies three types of process models: i) Product Flow Models: visualize the allocation of basic transformations to supply chain actors and the related product flows from input material into end products (including different traceability units based on the GS1 Global Traceability Standard); ii) Thread Diagrams: visualize how order driven and forecast driven processes are decoupled in specific supply chain configurations (positions Customer Order Decoupling Points), and how interdependences between processes are coordinated; iii) Business Process Diagrams: depict the sequence and interaction of control and coordination activities (as identified in Thread Diagrams) in BPMN notation. The framework is applied to several agrifood sectors, in particular potted plants and fruit supply chains. The main benefits are: i) It helps to map supply chain processes, including its control and coordination, in a timely, punctual and coherent way; ii) It supports a seamless translation of high level supply chain designs to detailed information engineering models; iii) It enables rapid instantiation of various supply chain configurations (instead of dictating a single blueprint); iv) It combines sector specific knowledge with reuse of knowledge provided by generic cross industry standards (SCOR, GS1)