5,102 research outputs found

    Quantifying Spatiotemporal Chaos in Rayleigh-B\'enard Convection

    Full text link
    Using large-scale parallel numerical simulations we explore spatiotemporal chaos in Rayleigh-B\'enard convection in a cylindrical domain with experimentally relevant boundary conditions. We use the variation of the spectrum of Lyapunov exponents and the leading order Lyapunov vector with system parameters to quantify states of high-dimensional chaos in fluid convection. We explore the relationship between the time dynamics of the spectrum of Lyapunov exponents and the pattern dynamics. For chaotic dynamics we find that all of the Lyapunov exponents are positively correlated with the leading order Lyapunov exponent and we quantify the details of their response to the dynamics of defects. The leading order Lyapunov vector is used to identify topological features of the fluid patterns that contribute significantly to the chaotic dynamics. Our results show a transition from boundary dominated dynamics to bulk dominated dynamics as the system size is increased. The spectrum of Lyapunov exponents is used to compute the variation of the fractal dimension with system parameters to quantify how the underlying high-dimensional strange attractor accommodates a range of different chaotic dynamics

    LOCV calculations for polarized liquid 3He^3{He} with the spin-dependent correlation

    Full text link
    We have used the lowest order constrained variational (LOCV) method to calculate some ground state properties of polarized liquid 3He^{3}He at zero temperature with the spin-dependent correlation function employing the Lennard-Jones and Aziz pair potentials. We have seen that the total energy of polarized liquid 3He^{3}He increases by increasing polarization. For all polarizations, it is shown that the total energy in the spin-dependent case is lower than the spin-independent case. We have seen that the difference between the energies of spin-dependent and spin-independent cases decreases by increasing polarization. We have shown that the main contribution of the potential energy comes from the spin-triplet state.Comment: 14 pages, 5 figures. Int. J. Mod. Phys. B (2008) in pres

    Comparison of the effect of topical application of Eugenia caryophylata extract and topical diclofenac in primary knee osteoarthritis: a clinical trial study

    Get PDF
    Background and aims: osteoarthritis is one of the most common arthritis in elderly. we evaluated to compare the effect of topical application of Eugenia caryophylata extract and topical diclofenac in primary knee osteoarthritis. Methods: This randomized double-blind clinical trial study was carried out upon 105 patients with primary knee osteoarthritis. Patients were selected randomly and divided into three groups of 35(diclofenac) and 35 (Eugenia caryophylata) and 35(placebo).The first group was given three times diclofenac 1 of one mg, the second group was given topical caryophylata 10 of one mg three times daily and third group was given placebo 1 mg three times daily. For three groups, WOMAC questionnaire (overall pain, knee pain, morning stiffness, stiffness during day, physical activity ) were completed pretreatment, one week and three and four weeks post-treatment. Findings: The findings indicated that there is a significant decrease in overall pain (p=o.oo5), stiffness during day (p=0.001), morning stiffness (p=0.001) and knee pain (p=0.017) and physical activity (p=0.001) in four weeks after the initiation of treatment in three groups of topical Eugenia caryophylata, diclofenac and placebo . In all the three groups, mean overall score of womac questionnaire was significantly decreased .no side effects related to the intake of medication in three groups was observed. Conclusion: Extract of Eugenia caryophylata is effective in decreasing knee pain, morning stiffness, and stiffness during day and improvement of physical activity in patients with knee osteoarthritis and it can be used alongside of chemical medication to reduce symptoms of knee osteoarthritis

    Transverse spectral functions and Dzyaloshinskii-Moriya interactions in XXZ spin chains

    Full text link
    Recently much progress has been made in applying field theory methods, first developed to study X-ray edge singularities, to interacting one dimensional systems in order to include band curvature effects and study edge singularities at arbitrary momentum. Finding experimental confirmations of this theory remains an open challenge. Here we point out that spin chains with uniform Dzyaloshinskii-Moriya (DM) interactions provide an opportunity to test these theories since these interactions may be exactly eliminated by a gauge transformation which shifts the momentum. However, this requires an extension of these X-ray edge methods to the transverse spectral function of the xxz spin chain in a magnetic field, which we provide

    Polarization control of single photon quantum orbital angular momentum states

    Full text link
    The orbital angular momentum of photons, being defined in an infinitely dimensional discrete Hilbert space, offers a promising resource for high-dimensional quantum information protocols in quantum optics. The biggest obstacle to its wider use is presently represented by the limited set of tools available for its control and manipulation. Here, we introduce and test experimentally a series of simple optical schemes for the coherent transfer of quantum information from the polarization to the orbital angular momentum of single photons and vice versa. All our schemes exploit a newly developed optical device, the so-called "q-plate", which enables the manipulation of the photon orbital angular momentum driven by the polarization degree of freedom. By stacking several q-plates in a suitable sequence, one can also access to higher-order angular momentum subspaces. In particular, we demonstrate the control of the orbital angular momentum mm degree of freedom within the subspaces of m=2|m|=2 \hbar and m=4|m|=4\hbar per photon. Our experiments prove that these schemes are reliable, efficient and have a high fidelity.Comment: 9 pages, 8 figure

    Green Economy as an Environment-based Framework for Indonesias Economic Reposition Structure

    Get PDF
    Economic development should consider the negative effects it creates. This will help to achieve a sustainable economic development. The green economic conceptcan be a solution to development process that works on natural resources conservation. This paper proposes a discriminant analysis to describe the green economic development. It analyses a group of countries, classified by their income levels. The analysis result suggests that environment factors such asemissions and area of the forest are important variables

    Minimum Cost Homomorphisms to Locally Semicomplete and Quasi-Transitive Digraphs

    Full text link
    For digraphs GG and HH, a homomorphism of GG to HH is a mapping $f:\ V(G)\dom V(H)suchthat such that uv\in A(G)implies implies f(u)f(v)\in A(H).If,moreover,eachvertex. If, moreover, each vertex u \in V(G)isassociatedwithcosts is associated with costs c_i(u), i \in V(H),thenthecostofahomomorphism, then the cost of a homomorphism fis is \sum_{u\in V(G)}c_{f(u)}(u).Foreachfixeddigraph. For each fixed digraph H,theminimumcosthomomorphismproblemfor, the minimum cost homomorphism problem for H,denotedMinHOM(, denoted MinHOM(H),canbeformulatedasfollows:Givenaninputdigraph), can be formulated as follows: Given an input digraph G,togetherwithcosts, together with costs c_i(u),, u\in V(G),, i\in V(H),decidewhetherthereexistsahomomorphismof, decide whether there exists a homomorphism of Gto to H$ and, if one exists, to find one of minimum cost. Minimum cost homomorphism problems encompass (or are related to) many well studied optimization problems such as the minimum cost chromatic partition and repair analysis problems. We focus on the minimum cost homomorphism problem for locally semicomplete digraphs and quasi-transitive digraphs which are two well-known generalizations of tournaments. Using graph-theoretic characterization results for the two digraph classes, we obtain a full dichotomy classification of the complexity of minimum cost homomorphism problems for both classes
    corecore