521 research outputs found

    Can the frequency-dependent specific heat be measured by thermal effusion methods?

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    It has recently been shown that plane-plate heat effusion methods devised for wide-frequency specific-heat spectroscopy do not give the isobaric specific heat, but rather the so-called longitudinal specific heat. Here it is shown that heat effusion in a spherical symmetric geometry also involves the longitudinal specific heat.Comment: Paper presented at the Fifth International Workshop on Complex Systems (Sendai, September, 2007), to appear in AIP Conference Proceeding

    Langevin Equation for the Rayleigh model with finite-ranged interactions

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    Both linear and nonlinear Langevin equations are derived directly from the Liouville equation for an exactly solvable model consisting of a Brownian particle of mass MM interacting with ideal gas molecules of mass mm via a quadratic repulsive potential. Explicit microscopic expressions for all kinetic coefficients appearing in these equations are presented. It is shown that the range of applicability of the Langevin equation, as well as statistical properties of random force, may depend not only on the mass ratio m/Mm/M but also by the parameter Nm/MNm/M, involving the average number NN of molecules in the interaction zone around the particle. For the case of a short-ranged potential, when N1N\ll 1, analysis of the Langevin equations yields previously obtained results for a hard-wall potential in which only binary collisions are considered. For the finite-ranged potential, when multiple collisions are important (N1N\gg 1), the model describes nontrivial dynamics on time scales that are on the order of the collision time, a regime that is usually beyond the scope of more phenomenological models.Comment: 21 pages, 1 figure. To appear in Phys. Rev.

    Two-Dimensional Dynamic Fusion for Continuous Authentication

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    Continuous authentication has been widely studied to provide high security and usability for mobile devices by continuously monitoring and authenticating users. Recent studies adopt multibiometric fusion for continuous authentication to provide high accuracy even when some of captured biometric data are of a low quality. However, existing continuous fusion approaches are resource-heavy as they rely on all classifiers being activated all the time and may not be suitable for mobile devices. In this paper, we propose a new approach to multibiometric continuous authentication: two-dimensional dynamic fusion. Our key insight is that multibiometric continuous authentication calculates two-dimensional matching scores over classifiers and over time. Based on this, we dynamically select a set of classifiers based on the context in which authentication is taking place, and fuse matching scores by multi-classifier fusion and multi-sample fusion. Through experimental evaluation, we show that our approach provides a better balance between resource usage and accuracy than the existing fusion methods. In particular, we show that our approach provides higher accuracy than the existing methods with the same number of score calculations by adopting multi-sample fusion.Comment: Accepted to IJCB'2

    Diffusive Evolution of Stable and Metastable Phases II: Theory of Non-Equilibrium Behaviour in Colloid-Polymer Mixtures

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    By analytically solving some simple models of phase-ordering kinetics, we suggest a mechanism for the onset of non-equilibrium behaviour in colloid-polymer mixtures. These mixtures can function as models of atomic systems; their physics therefore impinges on many areas of thermodynamics and phase-ordering. An exact solution is found for the motion of a single, planar interface separating a growing phase of uniform high density from a supersaturated low density phase, whose diffusive depletion drives the interfacial motion. In addition, an approximate solution is found for the one-dimensional evolution of two interfaces, separated by a slab of a metastable phase at intermediate density. The theory predicts a critical supersaturation of the low-density phase, above which the two interfaces become unbound and the metastable phase grows ad infinitum. The growth of the stable phase is suppressed in this regime.Comment: 27 pages, Latex, eps

    Time-convolutionless reduced-density-operator theory of a noisy quantum channel: a two-bit quantum gate for quantum information processing

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    An exact reduced-density-operator for the output quantum states in time-convolutionless form was derived by solving the quantum Liouville equation which governs the dynamics of a noisy quantum channel by using a projection operator method and both advanced and retarded propagators in time. The formalism developed in this work is general enough to model a noisy quantum channel provided specific forms of the Hamiltonians for the system, reservoir, and the mutual interaction between the system and the reservoir are given. Then, we apply the formulation to model a two-bit quantum gate composed of coupled spin systems in which the Heisenberg coupling is controlled by the tunneling barrier between neighboring quantum dots. Gate Characteristics including the entropy, fidelity, and purity are calculated numerically for both mixed and entangled initial states

    Crystal constructions in Number Theory

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    Weyl group multiple Dirichlet series and metaplectic Whittaker functions can be described in terms of crystal graphs. We present crystals as parameterized by Littelmann patterns and we give a survey of purely combinatorial constructions of prime power coefficients of Weyl group multiple Dirichlet series and metaplectic Whittaker functions using the language of crystal graphs. We explore how the branching structure of crystals manifests in these constructions, and how it allows access to some intricate objects in number theory and related open questions using tools of algebraic combinatorics

    Effect of temperature on rheology behaviour of banana peel pectin extracted using hot compressed water

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    Banana peel pectin is extracted from banana peel waste using a hot compressed water extraction (140-160°C, 5 minutes, 1.18 mm particle size). Physicochemical contents of banana peel pectin were found to be in a similar range with commercial pectin, and is comprised of moisture (7.44-8.47%), ash (3.45-4.98%), protein (1.08-1.92%), fat (0.04-3.42), carbohydrate (83-86%), total sugar (1.77-3.41%), energy (353-369 kcal/100g) and specific heat (1.42-1.62 kJ/kg°C). These contents possibly related to their flow deformation of rheological behaviour. Regression analysis displayed good agreements in all models applied, apart from the Casson Model. Flow behaviour indices, n<1 and decreasing of apparent viscosity within increasing of shear rate indicates that banana peel pectin has excellent shear thinning behaviour with a presence of yield stress

    Circulating Levels of Resistin and Risk of Type 2 Diabetes in Men and Women: Results From Two Prospective Cohorts

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    OBJECTIVE—The purpose of this study was to investigate the role of circulating resistin levels in the development of type 2 diabetes using two prospective cohorts of well-characterized men and women

    The Order Calculation in the Engineering Company

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    Import 23/07/2015Diplomová práce je zpracovávána ve společnosti Hagemann a.s. Celá práce se zabývá kalkulací veřejné zakázky Ministerstva vnitra ČR na dodání speciálně upravených policejních vozidel pro monitoring reálných hrozeb. Diplomová práce je rozdělena na dvě základní části, a to teoretickou část a praktickou část. První z částí je popsána problematika veřejných zakázek a hospodářská činnost v podniku. V druhé části je proveden rozbor předmětu veřejné zakázky. Dále byl zpracován návrh postupu plnění zakázky v prostorách společnosti, na které navazuje cenová kalkulace. V závěru práce jsou výsledky práce vyhodnoceny.Master thesis is processed in the company Hagemann a.s. The thesis deals with the calculation of public procurement from Ministry of the Interior to supply police vehicles specially adapted for monitoring real threats. The thesis is divided into two parts, the theoretical and practical part. The first part describes the issue of public procurement and economic activities in the company. The second part is analyzing subject of the contract. Further was processed a proposal for the execution of the contract in the company's premises, which is followed by a calculation and types of costs. In conclusion, the results of the work are evaluated.345 - Katedra mechanické technologievýborn

    The DNA Glycosylases Ogg1 and Nth1 Do Not Contribute to Ig Class Switching in Activated Mouse Splenic B Cells

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    During activation of B cells to undergo class switching, B cell metabolism is increased, and levels of reactive oxygen species (ROS) are increased. ROS can oxidize DNA bases resulting in substrates for the DNA glycosylases Ogg1 and Nth1. Ogg1 and Nth1 excise oxidized bases, and nick the resulting abasic sites, forming single-strand DNA breaks (SSBs) as intermediates during the repair process. In this study, we asked whether splenic B cells from mice deficient in these two enzymes would show altered class switching and decreased DNA breaks in comparison with wild-type mice. As the c-myc gene frequently recombines with the IgH S region in B cells induced to undergo class switching, we also analyzed the effect of deletion of these two glycosylases on DSBs in the c-myc gene. We did not detect a reduction in S region or c-myc DSBs or in class switching in splenic B cells from Ogg1- or Nth1-deficient mice or from mice deficient in both enzymes
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