585 research outputs found

    Building multidisciplinary, interdisciplinary, and transdisciplinary surveillance partnership

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    A discipline is a branch of knowledge. Examples are biology, chemistry and history. Real world problems are complex problems which do not respect artificial disciplinary boundaries. Public health surveillance is increasingly facing new challenges that require multiple disciplinary partnership to resolve. Partnership refers to two or more people or organizations that work together. The terms multidisciplinary, interdisciplinary and transdisciplinary are often used interchangeably but they have specific meanings. The objectives of this keynote presentation are to (1) define and compare the three multiple disciplinary approaches, using examples of several surveillance networks including the World Alliance for Risk Factor Surveillance (WARFS) and Americas' Network for Chronic Disease Surveillance (AMNET); (2) discuss a number of promotors of teamwork and partnership building; and (3) present a roadmap on where to find multiple disciplinary collaboration based on a review of the knowledge universe

    Ultrafast carrier relaxation in GaN, In_(0.05)Ga_(0.95)N and an In_(0.05)Ga_(0.95)/In_(0.15)Ga_(0.85)N Multiple Quantum Well

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    Room temperature, wavelength non-degenerate ultrafast pump/probe measurements were performed on GaN and InGaN epilayers and an InGaN multiple quantum well structure. Carrier relaxation dynamics were investigated as a function of excitation wavelength and intensity. Spectrally-resolved sub-picosecond relaxation due to carrier redistribution and QW capture was found to depend sensitively on the wavelength of pump excitation. Moreover, for pump intensities above a threshold of 100 microJ/cm2, all samples demonstrated an additional emission feature arising from stimulated emission (SE). SE is evidenced as accelerated relaxation (< 10 ps) in the pump-probe data, fundamentally altering the re-distribution of carriers. Once SE and carrier redistribution is completed, a slower relaxation of up to 1 ns for GaN and InGaN epilayers, and 660 ps for the MQW sample, indicates carrier recombination through spontaneous emission.Comment: submitted to Phys. Rev.

    Simulations of linear and nonlinear Rayleigh-Taylor instability under high Atwood numbers

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    Inertial confinement fusion (ICF) implosions, whether real or ideal, are subject to a variety of hydrodynamic instabilities that amplify small departures from spherical symmetry. Asymmetric implosions departing from spherical symmetry can lead to the breakup of the imploding shell or the creation of hydrodynamic turbulence. In an effort to understand the evolution of the asymmetries, perturbation seeds with both velocity and surface displacements have been introduced at the boundary of two different density media to model analytical Rayleigh-Taylor instability growth. Growth of perturbed amplitudes has been studied in linear and late-time nonlinear regimes. Simulated linear growth rates and nonlinear bubble velocities are in good agreement with theoretical values for Atwood numbers that are close to unity (relevant to ICF applications)

    Unique epidemiological patterns of human infections with H7N9 avian influenza virus discovered by combined risk factor surveillance and epidemiology

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    Background: An outbreak of a novel human avian influenza (H7N9) [h-H7N9 AI] took place in China from February 2013 to April 2015, with 628 reported cases. However, there were no exact answers on epidemiological patterns and its origin. Purpose: To examine the epidemiological patterns and its origin compared with other influenza outbreaks by combined analysis of risk factor surveillance and epidemiological characteristics, and to explore new surveillance methods for tracking infectious disease outbreaks

    Depression and health-adjusted life expectancy in the Canadian adult population: a descriptive study

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    Background: Few studies have evaluated the overall population health-related impact of depression in terms of losses to both premature mortality and health-related quality of life (HRQL). Purpose: To estimate health-adjusted life expectancy (HALE) for Canadian adults according to depression status

    Integral effect non-loca test results for the integral type reactor SMART-P using the VISTA facility

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    Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.The SMART-P a pilot plant of the integral type reactor SMART(System Integrated Modular Advanced Reactor) which has new innovative design features aimed at achieving a highly enhanced safety and improved economics. A test facility (VISTA) has been constructed to simulate the SMART-P which is a full height and 1/96 volume scaled test facility with respect to the SMART-P. The VISTA facility has been used to understand the thermal-hydraulic behavior including several operational transients and design basis accidents and finally it will contribute to verifying the system design of the SMART-P. During the past five years, several integral effect tests have been carried out and reported, including performance tests, MCP(Main Coolant Pump) transients, power transients and heatup or cooldown procedures. In the present study, the VISTA facility was subjected to the major safety related non-LOCA transient conditions in a primary and secondary system, including a power increase due to a CEDM (Control Element Drive Mechanism) withdrawal, a feedwater decrease and a steam flow increase in order to verify the safety analysis code for the SMART-P.cs201

    Coherent dynamics of Bose-Einstein condensates in high-finesse optical cavities

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    We study the mutual interaction of a Bose-Einstein condensed gas with a single mode of a high-finesse optical cavity. We show how the cavity transmission reflects condensate properties and calculate the self-consistent intra-cavity light field and condensate evolution. Solving the coupled condensate-cavity equations we find that while falling through the cavity, the condensate is adiabatically transfered into the ground state of the periodic optical potential. This allows time dependent non-destructive measurements on Bose-Einstein condensates with intriguing prospects for subsequent controlled manipulation.Comment: 5 pages, 5 figures; revised version: added reference

    Momentum state engineering and control in Bose-Einstein condensates

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    We demonstrate theoretically the use of genetic learning algorithms to coherently control the dynamics of a Bose-Einstein condensate. We consider specifically the situation of a condensate in an optical lattice formed by two counterpropagating laser beams. The frequency detuning between the lasers acts as a control parameter that can be used to precisely manipulate the condensate even in the presence of a significant mean-field energy. We illustrate this procedure in the coherent acceleration of a condensate and in the preparation of a superposition of prescribed relative phase.Comment: 9 pages incl. 6 PostScript figures (.eps), LaTeX using RevTeX, submitted to Phys. Rev. A, incl. small modifications, some references adde

    Many body physics from a quantum information perspective

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    The quantum information approach to many body physics has been very successful in giving new insight and novel numerical methods. In these lecture notes we take a vertical view of the subject, starting from general concepts and at each step delving into applications or consequences of a particular topic. We first review some general quantum information concepts like entanglement and entanglement measures, which leads us to entanglement area laws. We then continue with one of the most famous examples of area-law abiding states: matrix product states, and tensor product states in general. Of these, we choose one example (classical superposition states) to introduce recent developments on a novel quantum many body approach: quantum kinetic Ising models. We conclude with a brief outlook of the field.Comment: Lectures from the Les Houches School on "Modern theories of correlated electron systems". Improved version new references adde
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