36 research outputs found

    On the Applications of a New Technique to Solve Linear Differential Equations, with and without Source

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    A general method for solving linear differential equations of arbitrary order, is used to arrive at new representations for the solutions of the known differential equations, both without and with a source term. A new quasi-solvable potential has also been constructed taking recourse to the above method

    A novel realization of the Calogero-Moser scattering states as coherent states

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    A novel realization is provided for the scattering states of the NN-particle Calogero-Moser Hamiltonian. They are explicitly shown to be the coherent states of the singular oscillators of the Calogero-Sutherland model. Our algebraic treatment is straightforwardly extendable to a large number of few and many-body interacting systems in one and higher dimensions.Comment: 9 pages, REVTe

    Earthworm management in tropical agroecosystems

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    Collaborative research in the Macrofauna project has enabled development of some techniques that presently are at different stages of advancement, from promising pilot experiments (tomato production and inoculation in plant nursery bags at Yurimaguas and in India) to the fully developed technique of massive worm production and biofertilization of tea gardens in Tamil Nadu (India) (patent deposited). Failures have also helped to gain better insight into the potential feasibility of techniques that had been considered in the objectives of this project. Endogeic earthworms (#Pontoscolex corethrurus$) may be produced in large quantities, i.e.about 12000 worms (1.6-2.8 kg live wt)/m2/year in specific culture beds using either sawdust (Yurimaguas, Peru) or a mixture of high and low quality materials (Tamil Nadu, India) mixed into soil as substrates. Cost of production of 1 kg of earthworm biomass through bed culture is about 3.6 Euro, much lower than the cost of hand collection of worms from pastures/grasslands where these species are abundant (6-125 Euro depending on the cost of labour and earthworm density). The theorical value of an active earthworm community with an average biomass of 400 kg live wt has been estimated at 1400 Euro, the price that it would cost to reintroduce an equivalent biomass produced in our culture units, indicating the cost of land restoration. Direct inoculation of earthworms in the field to improve production may only affect plant growth positively if a large biomass (greater than 30 g live wt/m2) is inoculated from the beginning. An alternative may be to concentrate the inoculum in small areas regularly distributed across the field... (D'après résumé d'auteur

    Equivalence of the Calogero-Sutherland Model to Free Harmonic Oscillators

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    A similarity transformation is constructed through which a system of particles interacting with inverse-square two-body and harmonic potentials in one dimension, can be mapped identically, to a set of free harmonic oscillators. This equivalence provides a straightforward method to find the complete set of eigenfunctions, the exact constants of motion and a linear W1+W_{1+\infty} algebra associated with this model. It is also demonstrated that a large class of models with long-range interactions, both in one and higher dimensions can be made equivalent to decoupled oscillators.Comment: 9 pages, REVTeX, Completely revised, few new equations and references are adde

    An explicit realization of fractional statistics in one dimension

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    An explicit realization of anyons is provided, using the three-body Calogero model. The fact that in the coupling domain, 1/4<g<0-1/4<g<0, the angular spectrum can have a band structure, leads to the manifestation of the desired phase in the wave function, under the exchange of the paticles. Concurrently, the momentum corresponding to the angular variable is quantized, exactly akin to the relative angular momentum quantization in two dimensional anyonic systemComment: 12 page

    A Unified Algebraic Approach to Few and Many-Body Correlated Systems

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    The present article is an extended version of the paper {\it Phys. Rev.} {\bf B 59}, R2490 (1999), where, we have established the equivalence of the Calogero-Sutherland model to decoupled oscillators. Here, we first employ the same approach for finding the eigenstates of a large class of Hamiltonians, dealing with correlated systems. A number of few and many-body interacting models are studied and the relationship between their respective Hilbert spaces, with that of oscillators, is found. This connection is then used to obtain the spectrum generating algebras for these systems and make an algebraic statement about correlated systems. The procedure to generate new solvable interacting models is outlined. We then point out the inadequacies of the present technique and make use of a novel method for solving linear differential equations to diagonalize the Sutherland model and establish a precise connection between this correlated system's wave functions, with those of the free particles on a circle. In the process, we obtain a new expression for the Jack polynomials. In two dimensions, we analyze the Hamiltonian having Laughlin wave function as the ground-state and point out the natural emergence of the underlying linear W1+W_{1+\infty} symmetry in this approach.Comment: 18 pages, Revtex format, To appear in Physical Review

    Interferon and Ribavirin Combination Treatment Synergistically Inhibit HCV Internal Ribosome Entry Site Mediated Translation at the Level of Polyribosome Formation

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    Purpose:Although chronic hepatitis C virus (HCV) infection has been treated with the combination of interferon alpha (IFN-α) and ribavirin (RBV) for over a decade, the mechanism of antiviral synergy is not well understood. We aimed to determine the synergistic antiviral mechanisms of IFN-α and RBV combination treatment using HCV cell culture.Methods:The antiviral efficacy of IFN-α, RBV alone and in combination was quantitatively measured using HCV infected and replicon cell culture. Direct antiviral activity of these two drugs at the level of HCV internal ribosome entry site (IRES) mediated translation in Huh-7 cell culture was investigated. The synergistic antiviral effect of IFN-α and RBV combination treatment was verified using both the CalcuSyn Software and MacSynergy Software.Results:RBV combination with IFN-α efficiently inhibits HCV replication cell culture. Our results demonstrate that IFN-α, interferon lambda (IFN-λ) and RBV each inhibit the expression of HCV IRES-GFP and that they have a minimal effect on the expression of GFP in which the translation is not IRES dependent. The combination treatments of RBV along with IFN-α or IFN-λ were highly synergistic with combination indexes <1. We show that IFN-α treatment induce levels of PKR and eIF2α phosphorylation that prevented ribosome loading of the HCV IRES-GFP mRNA. Silencing of PKR expression in Huh-7 cells prevented the inhibitory effect of IFN-α on HCV IRES-GFP expression. RBV also blocked polyribosome loading of HCV-IRES mRNA through the inhibition of cellular IMPDH activity, and induced PKR and eIF2α phosphorylation. Knockdown of PKR or IMPDH prevented RBV induced HCV IRES-GFP translation.Conclusions:We demonstrated both IFN-α and RBV inhibit HCV IRES through prevention of polyribosome formation. The combination of IFN-α and RBV treatment synergistically inhibits HCV IRES translation via using two different mechanisms involving PKR activation and depletion of intracellular guanosine pool through inhibition of IMPDH

    Multi-robot path planning in a dynamic environment using improved gravitational search algorithm

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    This paper proposes a new methodology to optimize trajectory of the path for multi-robots using improved gravitational search algorithm (IGSA) in a dynamic environment. GSA is improved based on memory information, social, cognitive factor of PSO (particle swarm optimization) and then, population for next generation is decided by the greedy strategy. A path planning scheme has been developed using IGSA to optimally obtain the succeeding positions of the robots from the existing position. Finally, the analytical and experimental results of the multi-robot path planning have been compared with those obtained by IGSA, GSA and PSO in a similar environment. The simulation and the Khepera environmental results outperform IGSA as compared to GSA and PSO with respect to performance matrix

    Algebra for Fuzzy Object Oriented Database Language

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    An Efficient Algorithm for Mining Of frequent items using incremental model

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    Data mining is a part of know ledge Discovery in database process (KDD). As technology advances, floods of data can be produced and shared in many appliances such as wireless Sensor networks or Web click streams. This calls for extracting useful information and knowledge from streams of data. In this paper, We have proposed an efficient algorithm, where, at any time the current frequencies of all frequent item sets can be immediately produced. The current frequency of an item set in a stream is defined as its maximal frequency over all possible windows in the stream from any point in the past until the current state. The experimental result shows the proposed algorithm not only maintains a small summery of information for one item set but also consumes less memory then existing algorithms for mining frequent item sets over recent data streams
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