234 research outputs found

    A nonlocal inhomogeneous dispersal process

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    AbstractThis article in devoted to the study of the nonlocal dispersal equationut(x,t)=∫RJ(x−yg(y))u(y,t)g(y)dy−u(x,t)in R×[0,∞), and its stationary counterpart. We prove global existence for the initial value problem, and under suitable hypothesis on g and J, we prove that positive bounded stationary solutions exist. We also analyze the asymptotic behavior of the finite mass solutions as t→∞, showing that they converge locally to zero

    2-Vector Spaces and Groupoids

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    This paper describes a relationship between essentially finite groupoids and 2-vector spaces. In particular, we show to construct 2-vector spaces of Vect-valued presheaves on such groupoids. We define 2-linear maps corresponding to functors between groupoids in both a covariant and contravariant way, which are ambidextrous adjoints. This is used to construct a representation--a weak functor--from Span(Gpd) (the bicategory of groupoids and spans of groupoids) into 2Vect. In this paper we prove this and give the construction in detail.Comment: 44 pages, 5 figures - v2 adds new theorem, significant changes to proofs, new sectio

    Building theory of agri-food supply chain resilience using Total Interpretive Structural Modelling and MICMAC analysis

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    Agri-food supply chains are inherent with some unique characteristics and that can be easily disrupted compared with other supply chains. Therefore, supply chain resilience factors are relevant and can be taken into consideration. In this paper an attempt has been made to build a theoretical framework of resilience factors in agri-food supply chains with the help of total interpretive structural modelling and matrix of cross impact multiplications applied to classification analysis. The results of the total interpretive structural modelling demonstrate that leadership plays a vital role in enhancing the resilience of the agri-food supply chain. Furthermore, the matrix of cross impact multiplications applied to classification analysis results indicate that leadership and working team stability along with strong driving power should be given critical focus by agri-food supply chain managers to facilitate the improvement of agri-food supply chain resilience. This paper contributes to the extant theory building in the field of agri-food supply chain resilience, to fill the gap that a few researches have been conducted on agri-food supply chain resilience theory building

    Ligninolytic enzymes activities and SEM analysis of fungal inoculum of Anthracophyllum discolour

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    Fungal inocula are used for biotechnological applications especially in bioremediation process. They are formulated with a carrier, nutrient sources, binder, and lubricant to be encapsulated for a layer of fungal mycelium. The white-rot fungus Anthracophyllum discolor was studied for its ability to growth actively to form these inocula and to produce ligninolytic enzymes. In this study, fungal inocula were formulated on 3 different mixtures of lignocellulosic materials: F1, F2 and F3 and, two kind of fungal inocula were produced, coated and uncoated. The ligninolytic enzymes Laccase (Lac), Manganese Peroxidase (MnP), Manganese-independent Peroxidase (MiP) and Lignin Peroxidase (LiP) were measured during the experiments. The main enzymatic activity detected was Manganese Peroxidase for F1, F2 and, F3 tested and Laccase had the lowest activity. The amount of total ligninolytic enzyme activity was approximately 40% higher on uncoated than coated pellets, demonstrating the capacity of Anthracophy/lum discolor to growth and produce enzymes on this formulation. Uncoated pellet showed the highest MnP activity, after 15 days in average was 477,13 mmol/min/g being the pick of enzyme at the day 15 with 220,99 mmol/min/g. In contrast for coated pellets the MnP activity was 271,15 mmol/min/g. The UP was not detected on fungal inocula studied. Based on the results of ligninolytic enzymes, the fungal ability to growth and colonization on these pellet formulations showed by scanning electron microscopy (SEM), the pellet uncoated formulated with F1 lignocellulosic materials presents high potential to be used on bioremediation processes. These results will be presented and discussed

    Risk analysis of the agri-food supply chain: A multi-method approach

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    Agri-food supply chains (AFSCs) are becoming more complex in structure, and thus more susceptible to different vulnerabilities and risks. Therefore, to enhance performance, we need to manage the risks in AFSCs effectively and efficiently. This study analyses various AFSC risks using a multi-method approach, including thematic analysis, total interpretive structural modelling (TISM) and fuzzy cross-impact matrix multiplication applied to classification (MICMAC) analysis. Based on the empirical data collected from experienced AFSC practitioners and following thematic analysis, eight categories of risk and 16 risk factors were identified as important. Furthermore, the interrelationships among the identified risks were built using TISM. Finally, the identified risks were classified into various categories according to their dependence and driving power using fuzzy MICMAC analysis. The research results indicate that the weather-related and political risks have the highest driving power and are located at the lowest level in the TISM hierarchy. These risks have a high tendency to disturb the whole flow of AFSC and so should be managed effectively. This study advances existing literature on identifying risk factors, defining interrelations between different AFSC risks, and determining the key risks. The risk analysis results can help AFSC practitioners in AFSC to identify, categorise and analyse the risks

    Knowledge Mobilization for Agri-Food Supply Chain Decisions: Identification of Knowledge Boundaries and Categorization of Boundary-Spanning Mechanisms

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    The current world business environment is characterized by increasing uncertainties, complexities, and risks, which require agri-food supply chain (AFSC) managers to respond and act quickly in a context full of instability and unpredictability. Increasing pressure placed on AFSC managers intensifies the need to combine knowledge management (KM) and decision support that rapidly overcome knowledge boundaries. It has been recognized that the research issue related to the knowledge mobilization crossing boundaries in the AFSC needs to be addressed. This paper investigates knowledge boundaries and boundary-spanning mechanisms by collecting data from experienced AFSC practitioners. Empirical results verify that knowledge boundaries such as syntactic boundaries, semantic boundaries, and pragmatic boundaries could be effectively tackled by four specific boundary-spanning mechanisms: boundary spanners, boundary objects, boundary practices, and boundary discourses

    Blockchain technology in agri-food value chain management: A synthesis of applications, challenges and future research directions

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    Agri-food value chain is an area of significant importance because of providing sustainable, affordable, safety and sufficient food, feed, fibre and fuel to consumers, it is critical to ensure these value chains running smoothly and successfully by applying advanced internet technologies. Blockchain technology is a new digital technological approach underpinned by the Industry 4.0 to ensuring data integrity and preventing tampering and single point failure through offering fault-tolerance, immutability, trust, transparency and full traceability of the stored transaction records to all agri-food value chain partners. This paper used systematic literature network analysis to review the state-of-the-art blockchain technology including its recent advances, main applications in agri-food value chain and challenges from a holistic perspective. The findings suggest that blockchain technology together with advanced information and communication technology and internet of things have been adopted for the improvement of agri-food value chain management in four main aspects: traceability, information security, manufacturing and sustainable water management. Six challenges have been identified including storage capacity and scalability, privacy leakage, high cost and regulation problem, throughput and latency issue, and lack of skills. Based on the critical analysis of literature, research gaps and future research directions are proposed in this paper regarding the applications and challenges of blockchain technology in agri-food value chain management. This study makes contributions to the extant literature in the field of agri-food value chain management by discovering the potential of blockchain technology and its implications for agri-food value chain performance improvements such as food safety, food quality and food traceability

    Diversity of gut microflora is required for the generation of B cell with regulatory properties in a skin graft model

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    B cells have been reported to promote graft rejection through alloantibody production. However, there is growing evidence that B cells can contribute to the maintenance of tolerance. Here, we used a mouse model of MHC-class I mismatched skin transplantation to investigate the contribution of B cells to graft survival. We demonstrate that adoptive transfer of B cells prolongs skin graft survival but only when the B cells were isolated from mice housed in low sterility "conventional" (CV) facilities and not from mice housed in pathogen free facilities (SPF). However, prolongation of skin graft survival was lost when B cells were isolated from IL-10 deficient mice housed in CV facilities. The suppressive function of B cells isolated from mice housed in CV facilities correlated with an anti-inflammatory environment and with the presence of a different gut microflora compared to mice maintained in SPF facilities. Treatment of mice in the CV facility with antibiotics abrogated the regulatory capacity of B cells. Finally, we identified transitional B cells isolated from CV facilities as possessing the regulatory function. These findings demonstrate that B cells, and in particular transitional B cells, can promote prolongation of graft survival, a function dependent on licensing by gut microflora
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