10,323 research outputs found

    [Review of] Arjun Appadurai, Modernity at Large, Cultural Dimensions of Globalization

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    Modernity at Large is a collection of essays (most of which are reprinted from other sources, e.g., Public Culture) that link the themes of modernity and globalization to contemporary everyday social practice, and to group individual identity construction and expression. Appadurai takes up the conditions of modernity which for him include science as a dominant ideology, obsession with technological development, colonial social relations, and the primacy of national communities. Weaving these conditions with issues of globalization, which he defines as instantaneous worldwide telecommunications (phone, fax, and internet), increased international or transnational migration, the expanding scope and impact of mass media, and the surge in global tourism

    Flow cytometric detection of gamma interferon can effectively discriminate Mycobacterium bovis BCG-vaccinated cattle from M. bovis-infected cattle

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    Mycobacterium bovis is the causative agent of bovine tuberculosis, a disease that is increasing in incidence in United Kingdom cattle herds. In addition to increasing economic losses, the rise in bovine tuberculosis poses a human health risk. There is an urgent requirement for effective strategies for disease eradication; this will likely involve vaccination in conjunction with current test and slaughter policies. A policy involving vaccination would require an accurate diagnosis of M. bovis-infected animals and the potential to distinguish these animals from vaccinates. Currently used diagnostic tests, the skin test and gamma interferon (IFN-γ) blood test, have a sensitivity of up to 95%. A further complication is that M. bovis BCG-vaccinated animals are also scored positive by these tests. We tested the hypothesis that the quantification of IFN-γ-producing lymphocytes by flow cytometric analysis of intracellular IFN-γ expression would provide a more accurate discrimination of M. bovis-infected animals from BCG vaccinates. Significant numbers of IFN-γ-expressing CD4(+) T cells were detected following culture of heparinized blood from M. bovis-infected animals, but not from BCG vaccinates, with purified protein derived from M. bovis (PPD-B) or live mycobacteria. Only 1 of 17 BCG-vaccinated animals had a significant number of CD4(+) T lymphocytes expressing IFN-γ, compared with 21/22 M. bovis-infected animals. This assay could allow an accurate diagnosis of M. bovis and allow the discrimination of BCG-vaccinated cattle from infected cattle

    The Born and Markov approximations for atom lasers

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    We discuss the use of the Born and Markov approximations in describing the dynamics of an atom laser. In particular, we investigate the applicability of the quantum optical Born-Markov master equation for describing output coupling. We derive conditions based on the atomic reservoir, and atom dispersion relations for when the Born-Markov approximations are valid and discuss parameter regimes where these approximations fail in our atom laser model. Differences between the standard optical laser model and the atom laser are due to a combination of factors, including the parameter regimes in which a typical atom laser would operate, the different reservoir state which is appropriate for atoms, and the different dispersion relations between atoms and photons. We present results based on an exact method in the regimes in which the Born-Markov approximation fails. The exact solutions in some experimentally relavent parameter regimes give non-exponential loss of atoms from a cavity.Comment: 10 pages, 3 figures. (2 new figues). Exact solutions have been included in section II. Sections IV and V have been expanded. A new section discussing the effects of gravity has been include

    Stabilising entanglement by quantum jump-based feedback

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    We show that direct feedback based on quantum jump detection can be used to generate entangled steady states. We present a strategy that is insensitive to detection inefficiencies and robust against errors in the control Hamiltonian. This feedback procedure is also shown to overcome spontaneous emission effects by stabilising states with high degree of entanglement.Comment: 5 pages, 4 figure

    Best interests, dementia and the Mental Capacity Act (2005)

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    The Mental Capacity Act (2005) is an impressive piece of legislation that deserves serious ethical attention, but much of the commentary on the Act has focussed on its legal and practical implications rather than the underlying ethical concepts. This paper examines the approach that the Act takes to best interests. The Act does not provide an account of the underlying concept of best interests. Instead it lists factors that must be considered in determining best interests, and the Code of Practice to the Act states that this list is incomplete. This paper argues that this general approach is correct, contrary to some accounts of best interests. The checklist includes items that are unhelpful. Furthermore, neither the Act nor its Code of Practice provides sufficient guidance to carers faced with difficult decisions concerning best interests. This paper suggests ways in which the checklist can be developed and discusses cases that could be used in an updated Code of Practice

    Generating controllable atom-light entanglement with a Raman atom laser system

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    We introduce a scheme for creating continuous variable entanglement between an atomic beam and an optical field, by using squeezed light to outcouple atoms from a BEC via a Raman transition. We model the full multimode dynamics of the atom laser beam and the squeezed optical field, and show that with appropriate two-photon detuning and two-photon Rabi frequency, the transmitted light is entangled in amplitude and phase with the outcoupled atom laser beam. The degree of entanglement is controllable via changes in the two-photon Rabi frequency of the outcoupling process.Comment: 4 pages, 4 figure
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