118 research outputs found

    Simultaneous deformations and Poisson geometry

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    We consider the problem of deforming simultaneously a pair of given structures. We show that such deformations are governed by an L-infinity algebra, which we construct explicitly. Our machinery is based on Th. Voronov's derived bracket construction. In this paper we consider only geometric applications, including deformations of coisotropic submanifolds in Poisson manifolds, of twisted Poisson structures, and of complex structures within generalized complex geometry. These applications can not be, to our knowledge, obtained by other methods such as operad theory.Comment: 32 pages. Results in Section 2 improved (Lemma 2.6 and Corollaries 2.20, 2.22). Corollary 2.5 and Corollary 2.11 added. Final version, accepted for publicatio

    Nijenhuis and Compatible Tensors on Lie and Courant algebroids

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    We show that well known structures on Lie algebroids can be viewed as Nijenhuis tensors or pairs of compatible tensors on Courant algebroids. We study compatibility and construct hierarchies of these structures

    Analyticity, Unitarity and One-loop Graviton Corrections to Compton Scattering

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    We compute spin-flip cross section for graviton photoproduction on a spin-1/2 target of finite mass. Using this tree-level result, we find one-loop graviton correction to the spin-flip low-energy forward Compton scattering amplitude by using Gerasimov-Drell-Hearn sum rule. We show that this result agrees with the corresponding perturbative computations, implying the validity of the sum rule at one-loop level, contrary to the previous claims. We discuss possible effects from the black hole production and string Regge trajectory exchange at very high energies. These effects seem to soften the UV divergence present at one-loop graviton level. Finally, we discuss the relation of these observations with the models that involve extra dimensions.Comment: 15 pages, 3 figure

    Identity Drift:The Multivocality of Ethical Identity in Islamic Financial Institution

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    In today’s neo-liberalist world, Islamic financial institutions (IFIs) face many difficulties combining contemporary financial thinking with Islamic, faith-based principles, on which their day-to-day operations ought to be based. Hence, IFI are likely to experience shifts/changes in organizational and ethical identity due to tensions that the combination of these principles invokes. We present an in-depth case study that focuses on these shifts in a major European based IFI across a 14-year period. We conceptualize identity change as drift, highlighting the multivocal nature of identity construction. The ethico-faith principles that were meant to serve as living codes of ethics guiding the IFI’s organizational culture, operational processes, and strategy formation turned out to mainly have been discursively rationalized to respond to regulatory, market and institutional imperatives. The company is aware that it needs to engage in a continuous dialogue with those who set these requirements. Its ethico-faith principles may consequently be adapted quite radically, especially in periods of turmoil and takeover, as we show across the analysed time period. The paper provides valuable insights for faith-inspired organizations to reflect on the extent to which they wish to engage in the discursive justification and legitimization of current market hegemonies, whilst they actively encourage their managers to behave ethically as well

    A Novel, Low-Volume Method for Organ Culture of Embryonic Kidneys That Allows Development of Cortico-Medullary Anatomical Organization

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    Here, we present a novel method for culturing kidneys in low volumes of medium that offers more organotypic development compared to conventional methods. Organ culture is a powerful technique for studying renal development. It recapitulates many aspects of early development very well, but the established techniques have some disadvantages: in particular, they require relatively large volumes (1–3 mls) of culture medium, which can make high-throughput screens expensive, they require porous (filter) substrates which are difficult to modify chemically, and the organs produced do not achieve good cortico-medullary zonation. Here, we present a technique of growing kidney rudiments in very low volumes of medium–around 85 microliters–using silicone chambers. In this system, kidneys grow directly on glass, grow larger than in conventional culture and develop a clear anatomical cortico-medullary zonation with extended loops of Henle

    Down-Regulated NOD2 by Immunosuppressants in Peripheral Blood Cells in Patients with SLE Reduces the Muramyl Dipeptide-Induced IL-10 Production

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    Pattern recognition receptors (PRRs) such as Toll-like receptors are aberrantly expressed of peripheral blood mononuclear cells (PBMCs) in systemic lupus erythematosus (SLE) patients, for playing immunopathological roles. basal productions of cytokines (IL-6, IL-8 and IL-10) were significantly increased in immunosuppressant naïve patients and patients with active disease despite immunosuppressants compared with HCs. Upon MDP stimulaiton, relative induction (%) of cytokines (IL-1β) from PBMC was significantly increased in immunosuppressant naïve patients with inactive disease, and patients with active disease despite immunosuppressant treatment compared with HCs. Immunosuppressant usage was associated with a decreased basal production and MDP induced relative induction (%) of IL-10 in patients with inactive disease compared with immunosuppressant naïve patients and HCs.Bacterial exposure may increase the NOD2 expression in monocytes in immunosuppressant naïve SLE patients which can subsequently lead to aberrant activation of PBMCs to produce proinflammatory cytokines, implicating the innate immune response for extracellular pathogens in the immunopathological mechanisms in SLE. Immunosuppressant therapy may downregulate NOD2 expression in CD8+ T lymphocytes, monocytes, and DCs in SLE patients which subsequently IL-10 reduction, contributing towards the regulation of immunopathological mechanisms of SLE, at the expense of increasing risk of bacterial infection

    Sustainability in the face of institutional adversity : market turbulence, network embeddedness, and innovative orientation

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    International Alliance Strategies: A Case Study of the Indonesian Medical Device Industry

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    This study aims to investigate how the multinational corporations form alliance strategies with local businesses under the dynamic institutional environment in the Indonesian context. We used a qualitative approach with a case study of the medical device industry to examine how the institutional environment affects the choice of the strategic alliance. By collecting the qualitative data, including interviews, observations and archival data, the interpretive approach was adopted to understand social worlds from the point of view of participants. We identified five types of alliance strategies: the wholly owned subsidiary with contractual collaboration, the wholly owned subsidiary with the licence agreement, the international trade with the licence agreement, joint venture and outsourcing. There are also two main issues of the institutional environments that determine the choice of alliance strategic: the restriction for foreign companies to carry out direct selling and the new policy that introduces the electronic procurement system. This study provides evidence of the role of the institutional environment on collaboration strategies between the multinational enterprises from the developed countries and the local distributors from Indonesia. The results extend the concept of international business in the Asian context
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