73 research outputs found

    Natural star products on symplectic manifolds and quantum moment maps

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    We define a natural class of star products: those which are given by a series of bidifferential operators which at order kk in the deformation parameter have at most kk derivatives in each argument. We show that any such star product on a symplectic manifold defines a unique symplectic connection. We parametrise such star products, study their invariance and give necessary and sufficient conditions for them to yield a quantum moment map. We show that Kravchenko's sufficient condition for a moment map for a Fedosov star product is also necessary.Comment: Expanded bibliograph

    On Mpc-structures and Symplectic Dirac Operators

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    We prove that the kernels of the restrictions of symplectic Dirac or symplectic Dirac-Dolbeault operators on natural subspaces of polynomial valued spinor fields are finite dimensional on a compact symplectic manifold. We compute those kernels for the complex projective spaces. We construct injections of subgroups of the symplectic group (the pseudo-unitary group and the stabilizer of a Lagrangian subspace) in the group Mpc and classify G-invariant Mpc-structures on symplectic spaces with a G-action. We prove a variant of Parthasarathy's formula for the commutator of two symplectic Dirac-type operators on a symmetric symplectic space

    On the universal covering group of the real symplectic group

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    A model for the universal covering group of the symplectic group as a Lie group, and some calculations based on the model, as well as defining a similar model for the Lagrangian Grassmannian and relating our construction to the Maslov Index

    Traces for star products on symplectic manifolds

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    We give a direct elementary proof of the existence of traces for arbitrary star products on a symplectic manifold. We follow the approach we used in \cite{refs:GuttRaw}, solving first the local problem. A normalisation introduced by Karabegov \cite{refs:Karabegov} makes the local solutions unique and allows them to be pieced together to solve the global problem

    Lost conversations: finding new ways for black and white Australians to lead together

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    It\u27s time for a game-changer in how black and white Australians relate.   The difficulties we have in coming together—to talk, to work, to lead change—are core to our challenge to reconcile, as a country. But if we want to shift the status quo, if we want to lead change on entrenched Indigenous disadvantage, we don\u27t need another program, initiative or money to try and \u27fix\u27 the problem. We need to start having a different conversation.  The result of two years experience working together as part of a Social Leadership Australia initiative, Lost Conversations brings together the diverse perspectives and personal stories of five Aboriginal and four non-Indigenous authors, all with first-hand knowledge of what happens when black and white Australians come together to try and work on change.  Lost Conversations asks the questions and starts the conversations that we daren\u27t have in Australia ... until now:  What is \u27black\u27 power? What is \u27white\u27 power?  What qualifies someone to lead in this cross-cultural space?  Why is this so hard to talk about?  Can we start to name these things and try to shift the status quo?  Can we change?  Should we?  &nbsp

    On-farm pig dispatch methods employed in Brazil and stockpeople attitudes on their use

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    This study surveyed the on-farm dispatching methods used at pig farms, the characteristics of stockpeople operating them, in terms of training and management, and their opinions and attitudes about the efficiency and safety of the applied procedures. Independently of the pig type, the most used dispatching methods at the surveyed Brazilian farms were concussion (90%) and electrocution (5%). Both methods were reported as being efficient and safe for on-farm pig dispatching by most stockpeople (83%). However, 33% of all stockpeople reported they would prefer to use alternative methods, i.e., anesthetics (23%) or electrocution (32%). Only 7% of the stockpeople received training resulting in a more efficient application of the method (P < 0.05). Most stockpeople (96%) declared to feel uncomfortable with the dispatching procedure they use. This discomfort lasted for half a day or longer in 22% of them. The results of this survey suggest that the application of dispatching methods at pig farms may result in animal welfare issues related to the effectiveness of the methods and the attitudes of stockpeople

    TRAF2, an innate immune sensor, reciprocally regulates mitophagy and inflammation to maintain cardiac myocyte homeostasis

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    Mitochondria are essential for cardiac myocyte function, but damaged mitochondria trigger cardiac myocyte death. Although mitophagy, a lysosomal degradative pathway to remove damaged mitochondria, is robustly active in cardiac myocytes in the unstressed heart, its mechanisms and physiological role remain poorly defined. We discovered a critical role for TRAF2, an innate immunity effector protein with E3 ubiquitin ligase activity, in facilitating physiological cardiac myocyte mitophagy in the adult heart, to prevent inflammation and cell death, and maintain myocardial homeostasis

    Apolipoprotein M attenuates anthracycline cardiotoxicity and lysosomal injury

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    Apolipoprotein M (ApoM) binds sphingosine-1-phosphate (S1P) and is inversely associated with mortality in human heart failure (HF). Here, we show that anthracyclines such as doxorubicin (Dox) reduce circulating ApoM in mice and humans, that ApoM is inversely associated with mortality in patients with anthracycline-induced heart failure, and ApoM heterozygosity in mice increases Dox-induced mortality. In the setting of Dox stress, our studies suggest ApoM can help sustain myocardial autophagic flux in a post-transcriptional manner, attenuate Dox cardiotoxicity, and prevent lysosomal injury

    The Soft Power of Anglia: British Cold War Cultural Diplomacy in the USSR

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    This article contributes to the growing literature on the cultural Cold War through an exploration of the British national projection magazine Anglia, produced by the Foreign Office for distribution in the USSR from 1962 to 1992. As well as drawing attention to the significance of national magazines in general, the article sheds light on Britain's distinctive approach to propaganda and cultural diplomacy during the Cold War. It considers why the magazine was set up and endured for so long, despite considerable reservations about its value. It examines how Britain was projected in a manner that accorded with British understandings about the need for ‘subtle’ propaganda. Finally, it addresses the question of the magazine's impact in the USSR
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