1,052 research outputs found

    Exploring an Objective Weighting System for Travel & Tourism Pillars

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    AbstractThe World Economic Forum employs Travel & Tourism Competitiveness Indexes (TTCI) to measure the travel & tourism (T&T) global competitiveness of a country. The TTCI overall scores are calculated with an arithmetic mean aggregation from the scores of the fourteen composite pillars with a subjective assumption of all the pillars having the same weights. This paper attempts to release such a subjective assumption by proposing a new solution framework to explore an objective weighting system for the pillars. The proposed solution framework employs the Expectation Maximization (EM) clustering algorithm to group the 139 ranked countries into three classes and then performs the Artificial Neural Network (ANN) analysis to explore the objective weighting system for the fourteen pillars. The results show that tourism infrastructure, ground transport infrastructure, air transport infrastructure, cultural resources, health and hygiene, and ICT infrastructure are the six most critical pillars contributing to the TTCI overall scores. Accordingly, the policy makers should allocate limited resources with priority to improve these six pillars to frog leap the T&T global competitiveness

    PIN69 Cost Utility Analysis of 13-Valent Pneumococcal Conjugate Vaccine in Malaysia

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    Farrando Sicilia, Jordi; Lecea, Ignasi de; Fuente Fuente, Carlos; Ribas Seix, Anna; Masana Padrós, Judit; Delgado, José L

    A Co-axial Multi-tube Heat Exchanger Applicable for a Geothermal ORC Power Plant

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    AbstractThe study proposes a Co-axial multi-tube heat exchanger (CMTHE) applicable to geothermal heat extraction. The heat exchanger is integrated with a 50kW geothermal ORC power plant having a working fluid of R-245fa. Two field tests were performed to examine the system response of the ORC system subject to change of CMTHE. In case 1 where the flow rate in the shell-side of CMTHE is maintained, the pressure variation in the shell-side of CMTHE casts minor variations on heat extraction, ORC power generation, and ORC efficiency during the transient. Moreover, the effect of pressure has barely any influence of the final states of heat extraction, ORC power generation, and ORC efficiency. In case 2 where the pressure is preserved in the CMTHE, it is found that a decrease of flow rate in the CMTHE results in degradation of heat extraction, ORC power generation and ORC system efficiency. On the contrary, increasing the flow rate in the CMTHE leads to a rise of heat extraction, ORC power generation and ORC system efficiency. Unlike that in case 1, the effect of flow rate has a detectable effect on the final states of heat extraction, ORC power generation, and ORC efficiency

    Mesh update techniques for free-surface flow solvers using spectral element method

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    This paper presents a novel mesh-update technique for unsteady free-surface Newtonian flows using spectral element method and relying on the arbitrary Lagrangian--Eulerian kinematic description for moving the grid. Selected results showing compatibility of this mesh-update technique with spectral element method are given

    Charmed Exotics in Heavy Ion Collisions

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    Based on the color-spin interaction in diquarks, we argue that charmed multiquark hadrons are likely to exist. Because of the appreciable number of charm quarks produced in central nucleus-nucleus collisions at ultrarelativistic energies, production of charmed multiquark hadrons is expected to be enhanced in these collisions. Using both the quark coalescence model and the statistical hadronization model, we estimate the yield of charmed tetraquark meson TccT_{cc} and pentaquark baryon Θcs\Theta_{cs} in heavy ion collisions at RHIC and LHC. We further discuss the decay modes of these charmed exotic hadrons in order to facilitate their detections in experiments

    Thermodynamic and Tunneling Density of States of the Integer Quantum Hall Critical State

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    We examine the long wave length limit of the self-consistent Hartree-Fock approximation irreducible static density-density response function by evaluating the charge induced by an external charge. Our results are consistent with the compressibility sum rule and inconsistent with earlier work that did not account for consistency between the exchange-local-field and the disorder potential. We conclude that the thermodynamic density of states is finite, in spite of the vanishing tunneling density of states at the critical energy of the integer quantum Hall transition.Comment: 5 pages, 4 figures, minor revisions, published versio

    Skeletal muscle transcriptional coactivator PGC-1alpha mediates mitochondrial, but not metabolic, changes during calorie restriction

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    Calorie restriction (CR) is a dietary intervention that extends lifespan and healthspan in a variety of organisms. CR improves mitochondrial energy production, fuel oxidation, and reactive oxygen species (ROS) scavenging in skeletal muscle and other tissues, and these processes are thought to be critical to the benefits of CR. PGC-1alpha is a transcriptional coactivator that regulates mitochondrial function and is induced by CR. Consequently, many of the mitochondrial and metabolic benefits of CR are attributed to increased PGC-1alpha activity. To test this model, we examined the metabolic and mitochondrial response to CR in mice lacking skeletal muscle PGC-1alpha (MKO). Surprisingly, MKO mice demonstrated a normal improvement in glucose homeostasis in response to CR, indicating that skeletal muscle PGC-1alpha is dispensable for the whole-body benefits of CR. In contrast, gene expression profiling and electron microscopy (EM) demonstrated that PGC-1alpha is required for the full CR-induced increases in mitochondrial gene expression and mitochondrial density in skeletal muscle. These results demonstrate that PGC-1alpha is a major regulator of the mitochondrial response to CR in skeletal muscle, but surprisingly show that neither PGC-1alpha nor mitochondrial biogenesis in skeletal muscle are required for the whole-body metabolic benefits of CR

    A Farewell to Liouvillians

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    We examine the Liouvillian approach to the quantum Hall plateau transition, as introduced recently by Sinova, Meden, and Girvin [Phys. Rev. B {\bf 62}, 2008 (2000)] and developed by Moore, Sinova and Zee [Phys. Rev. Lett. {\bf 87}, 046801 (2001)]. We show that, despite appearances to the contrary, the Liouvillian approach is not specific to the quantum mechanics of particles moving in a single Landau level: we formulate it for a general disordered single-particle Hamiltonian. We next examine the relationship between Liouvillian perturbation theory and conventional calculations of disorder-averaged products of Green functions and show that each term in Liouvillian perturbation theory corresponds to a specific contribution to the two-particle Green function. As a consequence, any Liouvillian approximation scheme may be re-expressed in the language of Green functions. We illustrate these ideas by applying Liouvillian methods, including their extension to NL>1N_L > 1 Liouvillian flavors, to random matrix ensembles, using numerical calculations for small integer NLN_L and an analytic analysis for large NLN_L. We find that behavior at NL>1N_L > 1 is different in qualitative ways from that at NL=1N_L=1. In particular, the NL=N_L = \infty limit expressed using Green functions generates a pathological approximation, in which two-particle correlation functions fail to factorize correctly at large separations of their energy, and exhibit spurious singularities inside the band of random matrix energy levels. We also consider the large NLN_L treatment of the quantum Hall plateau transition, showing that the same undesirable features are present there, too
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