89,934 research outputs found

    The impact of income shocks on health: evidence from cohort data

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    We study the effect of permanent income innovations on health for a prime-aged population. Using information on more than half a million individuals sampled over a twenty-five year period in three different cross-sectional surveys we aggregate data by date-of-birth cohort to construct a ’synthetic cohort’ dataset with details of income, expenditure, socio-demographic factors, health outcomes and selected risk factors. We then exploit structural and arguably exogenous changes in cohort incomes over the eighties and nineties to uncover causal effects of permanent income shocks on health. We find that such income innovations have little effects on health, but do affect health behaviour and mortality

    From life cycle talking to taking action

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    Introduction - The biannual Life Cycle Management conference series aims to create a platform for users and developers of Life Cycle Assessment (LCA) and related tools to share their experiences. A key concern of the LCM community has been to move beyond the production of LCA reports toward using the developed knowledge. This paper reports and evaluates some of the main outcomes of the 4th International Life Cycle Management Conference (LCM 2009). Results - Conference focus: While the focus of the conference was LCM, LCA remains a main analytical tool for supporting LCM. This is clearly shown by the overall program in which roughly half of the contributions focused on or used LCA. Some products and resources and environmental themes were markedly represented in the presentation subjects. Conference participation: The 180 delegates included 40 South Africans, 20 from other African countries, and 140 from as far afield as Brazil, Sweden, Japan, and Australia. The surveyable number of delegates and conference rooms, in combination with the well-balanced scientific and social program, facilitated optimal professional exchange and discussion. Conference structure: LCM 2009 featured some 140 contributions from 47 leading environmental practitioners, consultants, and academic researchers. The interactive conference format included three plenary sessions and training workshops. Conclusions - LCM 2009 successfully engaged with the critical questions of what it means to manage (not merely shift) the environmental and social impacts of global economic activity, what this entails for industry and public services in emerging economies, and how supply chains, networks, and partnerships can be stimulated and managed to deliver truly sustainable practic

    No-cloning theorem in thermofield dynamics

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    We discuss the relation between the no-cloning theorem from quantum information and the doubling procedure used in the formalism of thermofield dynamics (TFD). We also discuss how to apply the no-cloning theorem in the context of thermofield states defined in TFD. Consequences associated to mixed states, von Neumann entropy and thermofield vacuum are also addressed.Comment: 16 pages, 3 figure

    Dynamics of bubbles in a two-component Bose-Einstein condensate

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    The dynamics of a phase-separated two-component Bose-Einstein condensate are investigated, in which a bubble of one component moves through the other component. Numerical simulations of the Gross--Pitaevskii equation reveal a variety of dynamics associated with the creation of quantized vortices. In two dimensions, a circular bubble deforms into an ellipse and splits into fragments with vortices, which undergo the Magnus effect. The B\'enard--von K\'arm\'an vortex street is also generated. In three dimensions, a spherical bubble deforms into toruses with vortex rings. When two rings are formed, they exhibit leapfrogging dynamics.Comment: 6 pages, 7 figure

    Identities in the Superintegrable Chiral Potts Model

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    We present proofs for a number of identities that are needed to study the superintegrable chiral Potts model in the Q0Q\ne0 sector.Comment: LaTeX 2E document, using iopart.cls with iopams packages. 11 pages, uses eufb10 and eurm10 fonts. Typeset twice! vs2: Two equations added. vs3: Introduction adde

    General U(N) gauge transformations in the realm of covariant Hamiltonian field theory

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    A consistent, local coordinate formulation of covariant Hamiltonian field theory is presented. While the covariant canonical field equations are equivalent to the Euler-Lagrange field equations, the covariant canonical transformation theory offers more general means for defining mappings that preserve the action functional - and hence the form of the field equations - than the usual Lagrangian description. Similar to the well-known canonical transformation theory of point dynamics, the canonical transformation rules for fields are derived from generating functions. As an interesting example, we work out the generating function of type F_2 of a general local U(N) gauge transformation and thus derive the most general form of a Hamiltonian density that is form-invariant under local U(N) gauge transformations.Comment: 36 pages, Symposium on Exciting Physics: Quarks and gluons/atomic nuclei/biological systems/networks, Makutsi Safari Farm, South Africa, 13-20 November 2011; Exciting Interdisciplinary Physics, Walter Greiner, Ed., FIAS Interdisciplinary Science Series, Springer International Publishing Switzerland, 201

    Enhanced energy relaxation process of quantum memory coupled with a superconducting qubit

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    For quantum information processing, each physical system has different advantage for the implementation and so hybrid systems to benefit from several systems would be able to provide a promising approach. One of the common hybrid approach is to combine a superconducting qubit as a controllable qubit and the other quantum system with a long coherence time as a memory qubit. The superconducting qubit allows us to have an excellent controllability of the quantum states and the memory qubit is capable of storing the information for a long time. By tuning the energy splitting between the superconducting qubit and the memory qubit, it is believed that one can realize a selective coupling between them. However, we have shown that this approach has a fundamental drawback concerning energy leakage from the memory qubit. The detuned superconducting qubit is usually affected by severe decoherence, and this causes an incoherent energy relaxation from the memory qubit to the superconducting qubit via the imperfect decoupling. We have also found that this energy transport can be interpreted as an appearance of anti quantum Zeno effect induced by the fluctuation in the superconducting qubit. We also discuss a possible solution to avoid such energy relaxation process, which is feasible with existing technology

    Dynamical creation of entanglement by homodyne-mediated feedback

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    For two two-level atoms coupled to a single-mode cavity field that is driven and heavily damped, the steady-state can be entangled by shining an un-modulated driving laser on the system [S.Schneider, G. J. Milburn Phys. Rev A 65, 042107, 2002]. We present a scheme to significantly increase the steady-state entanglement by using homodyne-mediated feedback, in which the driving laser is modulated by the homodyne photocurrent derived from the cavity output. Such feedback can increase the nonlinear response to both the decoherence process of the two-qubit system and the coherent evolution of individual qubits. We present the properties of the entangled states using the SO(3) Q function.Comment: 8 page
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