64 research outputs found

    The role of the mitochondria and the endoplasmic reticulum contact sites in the development of the immune responses

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    Abstract Mitochondria and endoplasmic reticulum (ER) contact sites (MERCs) are dynamic modules enriched in subset of lipids and specialized proteins that determine their structure and functions. The MERCs regulate lipid transfer, autophagosome formation, mitochondrial fission, Ca2+ homeostasis and apoptosis. Since these functions are essential for cell biology, it is therefore not surprising that MERCs also play a critical role in organ physiology among which the immune system stands by its critical host defense function. This defense system must discriminate and tolerate host cells and beneficial commensal microorganisms while eliminating pathogenic ones in order to preserve normal homeostasis. To meet this goal, the immune system has two lines of defense. First, the fast acting but unspecific innate immune system relies on anatomical physical barriers and subsets of hematopoietically derived cells expressing germline-encoded receptors called pattern recognition receptors (PRR) recognizing conserved motifs on the pathogens. Second, the slower but very specific adaptive immune response is added to complement innate immunity. Adaptive immunity relies on another set of specialized cells, the lymphocytes, harboring receptors requiring somatic recombination to be expressed. Both innate and adaptive immune cells must be activated to phagocytose and process pathogens, migrate, proliferate, release soluble factors and destroy infected cells. Some of these functions are strongly dependent on lipid transfer, autophagosome formation, mitochondrial fission, and Ca2+ flux; this indicates that MERCs could regulate immunity

    Explaining the effect of rapid internationalization on horizontal foreign divestment in the retail sector. An extended penrosean perspective

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    Building on and extending Penrosean logic we argue that rapid international expansion by firms might lead to a breach of Penrosean constraints on efficient expansion and to subsequent divestment of international operations to bring firm scope back into Penrosean constraints. We further predict that intra-regional concentration and international experience moderate the above effect because they influence firms ability to avoid a breach of Penrosean constraints and/or weaken the consequences of such a breach. Using data on the international expansion and divestment of large retail MNEs over the period 2003-2012 we find empirical support for the proposed extended Penrose effect in explaining international divestment as well as for the moderating effects of intra-regional concentration and international experience. Our study contributes to the development of Penrosean logic and to our understanding of the factors that drive firms to divest overseas operations

    Reducing Information Variation in Text

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    Reducing Information Variation in Text

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    A decision support system for assessing offshore wind energy potential in the North Sea

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    Offshore wind energy (OWE) in the North Sea has the potential to meet large share of Europe’s future electricity demand. To deploy offshore wind parks in a rational way, the overall OWE potential has to be realistically determined. This has to be done on an international, cross-border level and by taking into account the existing man-made and nature-related uses of the North Sea. As spatial conflicts will arise between existing uses and the new OWE uses, a Decision Support System (DSS) based on a Geographic Information System (GIS) was developed. Based on data of existing sea uses and calculation rules for spatial prioritisation analysis, the DSS helps in identifying areas that are (1) generally suitable for offshore wind power, (2) strictly excluded or (3) negotiable with respect to other existing sea uses. The combination of this conflict analysis together with cost assumptions for offshore wind farms and their expected electricity yield leads to identification of favourable areas for OWE deployment in the North Sea. This approach helps to reduce the conflict between offshore wind deployment and existing sea uses in the North Sea for future planning. The results can assist decision makers in developing transnational roadmaps for OWE
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