3,895 research outputs found

    Remarks on NonHamiltonian Statistical Mechanics: Lyapunov Exponents and Phase-Space Dimensionality Loss

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    The dissipation associated with nonequilibrium flow processes is reflected by the formation of strange attractor distributions in phase space. The information dimension of these attractors is less than that of the equilibrium phase space, corresponding to the extreme rarity of nonequilibrium states. Here we take advantage of a simple model for heat conduction to demonstrate that the nonequilibrium dimensionality loss can definitely exceed the number of phase-space dimensions required to thermostat an otherwise Hamiltonian system.Comment: 5 pages, 2 figures, minor typos correcte

    A Multicriteria Analysis on the Strategies to Open Taiwan's Mobile Virtual Network Operators Services

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    [[abstract]]This study investigates the trends followed by MVNOs (Mobile Virtual Network Operators) in the last three years and analyzes the strategies that can contribute to the success of Taiwan's telecommunications industry and marketing. We apply the method and concept of PATTERN (Planning Assistance Through Technical Evaluation of Relevance Number) to establish relevant systems for searching out the key successful factors of strategies to attract MVNOs. We also use the fuzzy Multi-Criteria Decision Making (MCDM) method for analyzing the different preference of a decision group in the criteria weights and for ranking the alternatives in a fuzzy environment in order to provide a strategy scheme. These results provide a reference to assist telecommunications operators, 3G license owners, potential MVNOs, and equipment manufacturers when working out business plans.[[incitationindex]]SCI[[booktype]]紙

    Suppression of core polarization in halo nuclei

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    We present a microscopic study of halo nuclei, starting from the Paris and Bonn potentials and employing a two-frequency shell model approach. It is found that the core-polarization effect is dramatically suppressed in such nuclei. Consequently the effective interaction for halo nucleons is almost entirely given by the bare G-matrix alone, which presently can be evaluated with a high degree of accuracy. The experimental pairing energies between the two halo neutrons in 6^6He and 11^{11}Li nuclei are satisfactorily reproduced by our calculation. It is suggested that the fundamental nucleon-nucleon interaction can be probed in a clearer and more direct way in halo nuclei than in ordinary nuclei.Comment: 11 pages, RevTex, 2 postscript figures; major revisions, matches version to appear in Phys. Rev. Letter

    Probabilistic Bisimulation: Naturally on Distributions

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    In contrast to the usual understanding of probabilistic systems as stochastic processes, recently these systems have also been regarded as transformers of probabilities. In this paper, we give a natural definition of strong bisimulation for probabilistic systems corresponding to this view that treats probability distributions as first-class citizens. Our definition applies in the same way to discrete systems as well as to systems with uncountable state and action spaces. Several examples demonstrate that our definition refines the understanding of behavioural equivalences of probabilistic systems. In particular, it solves a long-standing open problem concerning the representation of memoryless continuous time by memory-full continuous time. Finally, we give algorithms for computing this bisimulation not only for finite but also for classes of uncountably infinite systems

    Angular Dependences of Third Harmonic Generation from Microdroplets

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    We present experimental and theoretical results for the angular dependence of third harmonic generation (THG) of water droplets in the micrometer range (size parameter 62<ka<24862<ka<248). The THG signal in pp- and ss-polarization obtained with ultrashort laser pulses is compared with a recently developed nonlinear extension of classical Mie theory including multipoles of order l250l\leq250. Both theory and experiment yield over a wide range of size parameters remarkably stable intensity maxima close to the forward and backward direction at ``magic angles''. In contrast to linear Mie scattering, both are of comparable intensity.Comment: 4 pages, RevTeX, 3 figures available on request from [email protected], submitted to PR

    Two-frequency shell model for hypernuclei and meson-exchange hyperon-nucleon potentials

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    A two-frequency shell model is proposed for investigating the structure of hypernuclei starting with a hyperon-nucleon potential in free space. In a calculation using the folded-diagram method for Λ¹⁶O, the Λ single particle energy is found to have a saturation minimum at an oscillator frequency ħωΛ≈10MeV, for the Λ orbit, which is considerably smaller than ħωN=14MeV for the nucleon orbit. The spin-dependence parameters derived from the Nijmegen NSC89 and NSC97f potentials are similar, but both are rather different from those obtained with the Jülich-B potential. The ΛNN three-body interactions induced by ΛN-ΣN transitions are important for the spin parameters, but relatively unimportant for the low-lying states of Λ¹⁶O.Yiharn Tzeng, S. Y. Tsay Tzeng, T. T. S. Kuo, T.-S.H. Lee, and V. G. D. Stok

    DETC2011-48877 A SIMPLIFIED INTEGRATION SYSTEM FOR THE FABRICATION OF TOTAL SURFACE BEARING TRANSTIBIAL SOCKET BY EMPLOYING RAPID PROTOTYPING TECHNOLOGY

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    ABSTRACT This project is to validate the preliminary result of rapid prototyping (RP)-based transtibial socket that was reinforced by wrapping a layer of unsaturated polyester resin. By employing contemporary technologies including a scanner, computer-aided engineering systems, a rapid prototyping machine, together with the expertise of a prosthetist, RP-based prosthetic sockets with a comfortable fit to volunteer amputees can be fabricated. However, the expensive cost and complex procedure of using current commercial scanners and CAD systems will be barriers experienced by clinical professionals. As the existing service bureau infrastructure and cheaper RP technology are easily accessed, fabrication and technology cost barriers will be reduced. The remaining problems include the availability of easily-used CAD systems for designing prosthetic sockets, simple scanner and stump duplicating tool. This study therefore focuses on the integration of simplified systems including a vacuum forming tool, compact scanner and an interface system for designing prosthetic sockets. Although the type of PTB (patella tendon bearing) transtibial socket is widely adopted in plaster-based manual process, TSB (total surface bearing) sockets are more acceptable by amputees. Since the concept of TSB socket should obtain the stump mold of an amputee under appropriate pressure by using a specific stump forming tool, editing complex surfaces can be avoided when using a TSB-based stump model to design a socket. The quality of socket fit is expected to improve by a simplified design process in which an interface system based on grid-editing algorithms is utilized. Correspondence: L.H. Hsu, Department of Mechanical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan. E-mail: [email protected] In addition, cheaper RP technology, such as 3-D printing or droplet binding process, can be alternative means to fabricate RP-based prosthetic sockets. By combining TSB stump mold, simplified design process and a cheaper RP machine, this study proposes a simplified integrating system to manufacture RP stump mold. Using this RP stump mold together with the traditional lamination method of infiltrating resin into cotton layers, the RP-based transtibial sockets will then be fabricated easily. The expected result will demonstrate the feasibility of employing cheaper emerging technologies to assist an unskilled prosthetist who will be able to produce good quality of prosthetic socket

    CD40 signal rewires fatty acid and glutamine metabolism for stimulating macrophage anti-tumorigenic functions.

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    Exposure of lipopolysaccharide triggers macrophage pro-inflammatory polarization accompanied by metabolic reprogramming, characterized by elevated aerobic glycolysis and a broken tricarboxylic acid cycle. However, in contrast to lipopolysaccharide, CD40 signal is able to drive pro-inflammatory and anti-tumorigenic polarization by some yet undefined metabolic programming. Here we show that CD40 activation triggers fatty acid oxidation (FAO) and glutamine metabolism to promote ATP citrate lyase-dependent epigenetic reprogramming of pro-inflammatory genes and anti-tumorigenic phenotypes in macrophages. Mechanistically, glutamine usage reinforces FAO-induced pro-inflammatory and anti-tumorigenic activation by fine-tuning the NAD &lt;sup&gt;+&lt;/sup&gt; /NADH ratio via glutamine-to-lactate conversion. Genetic ablation of important metabolic enzymes involved in CD40-mediated metabolic reprogramming abolishes agonistic anti-CD40-induced antitumor responses and reeducation of tumor-associated macrophages. Together these data show that metabolic reprogramming, which includes FAO and glutamine metabolism, controls the activation of pro-inflammatory and anti-tumorigenic polarization, and highlight a therapeutic potential of metabolic preconditioning of tumor-associated macrophages before agonistic anti-CD40 treatments
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