Mapping the Greek Wine Supply Chain: A Proposed Research Framework

The wine industry involves both the production (i.e., from vine to wine) and consumption of wine (i.e., dining and tourism experiences). This results in a complicated system of intertwined product and services supply chains. Recent studies in the field suggest several key perspectives for future research, such as sustainability, resilience and circular economy. However, the complex nature of the sector which comprises numerous stakeholders and flows (i.e., products—services—information), entailing knotty interactions and interdependencies, makes any research direction questionable in terms of its effectiveness. Therefore, the objective of this study is to provide a tool for designing targeted future research in such multiple environments. We employed an end-to-end mapping approach using data from the Greek wine supply chain, identifying essential insights for a compelling research agenda. The key output is a set of three supply chain maps revealing the structure, processes and actors from all the main angles: basic production, value chain and stakeholders. A synthesis of these maps supports an overall understanding of the sector, unmasking any interaction and hidden information holdups. The study thus aims to offer an integrated research framework that highlights the leading priorities of the Greek wine industry.

Weighted Homology of Bi-Structures over Certain Discrete Valuation Rings

An RNA bi-structure is a pair of RNA secondary structures that are considered as arc-diagrams. We present a novel weighted homology theory for RNA bi-structures, which was obtained through the intersections of loops. The weighted homology of the intersection complex X features a new boundary operator and is formulated over a discrete valuation ring, R. We establish basic properties of the weighted complex and show how to deform it in order to eliminate any 3-simplices. We connect the simplicial homology, Hi(X), and weighted homology, Hi,R(X), in two ways: first, via chain maps, and second, via the relative homology. We compute H0,R(X) by means of a recursive contraction procedure on a weighted spanning tree and H1,R(X) via an inflation map, by which the simplicial homology of the 1-skeleton allows us to determine the weighted homology H1,R(X). The homology module H2,R(X) is naturally obtained from H2(X) via chain maps. Furthermore, we show that all weighted homology modules Hi,R(X) are trivial for i>2. The invariant factors of our structure theorems, as well as the weighted Whitehead moves facilitating the removal of filled tetrahedra, are given a combinatorial interpretation. The weighted homology of bi-structures augments the simplicial counterpart by introducing novel torsion submodules and preserving the free submodules that appear in the simplicial homology.

Čech–Delaunay gradient flow and homology inference for self-maps

We call a continuous self-map that reveals itself through a discrete set of point-value pairs a sampled dynamical system. Capturing the available information with chain maps on Delaunay complexes, we use persistent homology to quantify the evidence of recurrent behavior. We establish a sampling theorem to recover the eigenspaces of the endomorphism on homology induced by the self-map. Using a combinatorial gradient flow arising from the discrete Morse theory for Čech and Delaunay complexes, we construct a chain map to transform the problem from the natural but expensive Čech complexes to the computationally efficient Delaunay triangulations. The fast chain map algorithm has applications beyond dynamical systems.

Mapping Sustainable Tomato Supply Chain in Greece: A Framework for Research

Sustainable food supply chains are complex systems involving several stakeholders, processes, flow of goods/materials and information. The value generated in combination with the contradictory agendas among actors makes any groundwork for future research a challenging endeavor. Hence, an end-to-end mapping of the food supply chain under examination is a vital prerequisite for the design of a comprehensive research framework. This study exemplified such a mapping approach in the Greek sustainable tomato supply chain, providing significant insights for an impactful research agenda. Data were obtained from secondary sectoral sources and open interviews with key players across the supply chain—covering all its main stages, i.e., production, packaging, storing, transportation, wholesaling, and retailing. The findings are summarized in three supply chain maps that illustrate the areas concerning sustainability, value chain and stakeholders. These maps synthesize a bigger picture of the supply chain that reveals the complicated interactions among its actors, the hidden bottlenecks in the flow of information and the areas that need deeper exploration. Its fundamental implication is the design of a targeted research framework, underlying the main priorities of the Greek tomato supply chain and eventually the Greek agri-food sector.

Multi-stakeholder partnerships in value chain development

Purpose The purpose of this paper is to demonstrate that agricultural commodity value chain development using multi-stakeholder partnerships (MSPs) can fast-track improvement in the livelihoods of rural farming households. With the view that such partnerships can raise farmers’ incomes, the study uses the case of the organic pineapple (OP) value chain in Ntungamo, Western Uganda, to understand the governance features that hold the value chain partners together, to analyse the costs and margins to the participating farmers, to identify opportunities for demand-driven upgrading of the farmers’ skills and knowledge, and the role that partnerships play in such upgrading. Design/methodology/approach The study uses the qualitative tools of value chain analysis: value chain maps of stakeholders, processes and support services of the OP value chain, and a quantitative tool to analyse costs and margins to the participating farmers. Interviews were conducted with key informants from the OP innovation platform, and survey data collected for the planting season, February–July, 2014, across three farmer categories of certified organic, conventional, and farmers not participating in the innovation platform. Findings Careful selection of partnerships to develop the value chain is found to be critical. Partners to involve should be those that enable the upgrading of farmers’ knowledge, skills and technologies to position them for better markets. Partners should also include those that enable the improvement of margins to the farmers and efficiency of the value chain. The strategic MSPs should be bound by formal contracts, to ensure stable relationships in the value chain and hence sustainable market access for the farmers. Research limitations/implications Although carried out on a specific value chain in a specific local context, this is not likely to limit the applicability of the findings to commodity value chains in a range of local contexts. Originality/value The study fulfils the need to highlight the role that stakeholder partnerships can play in value chain development and how they can be sustained by governance and institutional arrangements.

(4,2)-CHAIN HOMOTOPY

We consider (4,2)-chain homotopy for (4,2)-chain maps between (4,2)-chain complexes (weak or strong), andprove that if f and g are (4,2)-chain homotopic, then they induce the same homomorphisms on the (4,2)-homologygroups for the correspondent (4,2)-chain complexes.

Homotopic Chain Maps Have Equals-Homology andd-Homology

The homotopy of chain maps on preabelian categories is investigated and the equality of standard homologies andd-homologies of homotopic chain maps is established. As a special case, ifXandYare the same homotopy type, then theirnthd-homologyR-modules are isomorphic, and ifXis a contractible space, then itsnthd-homologyR-modules forn≠0are trivial.