1,543 research outputs found

    Comments on the Equivalence between Chern-Simons Theory and Topological Massive Yang-Mills Theory in 3D

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    The classical formal equivalence upon a redefinition of the gauge connection between Chern-Simons theory and topological massive Yang-Mills theory in three-dimensional Euclidean space-time is analyzed at the quantum level within the BRST formulation of the Equivalence Theorem. The parameter controlling the change in the gauge connection is the inverse λ\lambda of the topological mass. The BRST differential associated with the gauge connection redefinition is derived and the corresponding Slavnov-Taylor (ST) identities are proven to be anomaly-free. The Green functions of local operators constructed only from the (λ\lambda-dependent) transformed gauge connection, as well as those of BRST invariant operators, are shown to be independent of the parameter λ\lambda, as a consequence of the validity of the ST identities. The relevance of the antighost-ghost fields, needed to take into account at the quantum level the Jacobian of the change in the gauge connection, is analyzed. Their role in the identification of the physical states of the model within conventional perturbative gauge theory is discussed.Comment: 19 pages, LATEX, to appear in Journal of High Energy Physic

    Delay Tolerant Networking over the Metropolitan Public Transportation

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    We discuss MDTN: a delay tolerant application platform built on top of the Public Transportation System (PTS) and able to provide service access while exploiting opportunistic connectivity. Our solution adopts a carrier-based approach where buses act as data collectors for user requests requiring Internet access. Simulations based on real maps and PTS routes with state-of-the-art routing protocols demonstrate that MDTN represents a viable solution for elastic nonreal-time service delivery. Nevertheless, performance indexes of the considered routing policies show that there is no golden rule for optimal performance and a tailored routing strategy is required for each specific case

    The Hierarchy Principle and the Large Mass Limit of the Linear Sigma Model

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    In perturbation theory we study the matching in four dimensions between the linear sigma model in the large mass limit and the renormalized nonlinear sigma model in the recently proposed flat connection formalism. We consider both the chiral limit and the strong coupling limit of the linear sigma model. Our formalism extends to Green functions with an arbitrary number of pion legs,at one loop level,on the basis of the hierarchy as an efficient unifying principle that governs both limits. While the chiral limit is straightforward, the matching in the strong coupling limit requires careful use of the normalization conditions of the linear theory, in order to exploit the functional equation and the complete set of local solutions of its linearized form.Comment: Latex, 41 pages, corrected typos, final version accepted by IJT

    A pedagogical introduction to the Slavnov formulation of quantum Yang-Mills theory

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    Over the last few years, Slavnov has proposed a formulation of quantum Yang-Mills theory in the Coulomb gauge which preserves simultaneously manifest Lorentz invariance and gauge invariance of the ghost field Lagrangian. This paper presents in detail some of the necessary calculations, i.e. those dealing with the functional integral for the S-matrix and its invariance under shifted gauge transformations. The extension of this formalism to quantum gravity in the Prentki gauge deserves consideration.Comment: 16 pages, review pape

    On a class of embeddings of massive Yang-Mills theory

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    A power-counting renormalizable model into which massive Yang-Mills theory is embedded is analyzed. The model is invariant under a nilpotent BRST differential s. The physical observables of the embedding theory, defined by the cohomology classes of s in the Faddeev-Popov neutral sector, are given by local gauge-invariant quantities constructed only from the field strength and its covariant derivatives.Comment: LATEX, 34 pages. One reference added. Version published in the journa

    Preference of farmers towards private and public extension services

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    The main purpose of this study was to know the preference of farmers for different services provided by private and public extension agencies. In recent times involvement of private extension agencies has been increased in agricultural sector and up to some extent it has sidelined the public extension agencies, but public extension agencies have potential to do better and to reach farmers at their best. In view of this, present study was undertaken to find out the farmers’ preference towards public and private extension services in Ambala, Kurukshetra, Karnal, Hisar and Fatehabad districts of Haryana state. From each district two blocks were selected randomly and from each block two villages were selected. A manageable size of 10 farmers was selected from each village thus making total sample size of 200 farmers. Various aspects related to agricultural services provided by both public and private agencies were identified and response were obtained by putting a tick mark as per farmers’ preference for private and public agencies. On the basis of statistical tools like rank and mean score, results showed that farmers had great preference for ‘Input supply’ in private extension as compared to public extension followed by ‘Infrastructure facilities’. While for ‘Consultancy and diagnosis services’, ‘Information’ and ‘Technical services’, public extension was preferred as over the private extension

    Disease and pest management in apple: Farmers' perception and adoption in J&K state

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    Diseases and pests are one of the limiting factors for low productivity of the fruit crops in Kashmir valley, India. A study on management of resources with respect to disease and pest management of apple and extent of adoption of recommended plant protection technology was undertaken for increasing apple production in Kashmir valley of J and K State. District Baramulla was selected purposively on the basis of maximum area and production under apple crop. A sample size of 200 apple growers 50 each from 4 villages were selected randomly. The study revealed that the perception index regarding attributes of technology recommended in two diseases viz. San Jose Scale and Apple Scab was 68.88% and 80.76% in respect of profitability (83.97%), simplicity-complexity each 63.57% and 54.27 % for practicability attributes of technology. The data further showed that the farmers adoption level under Chemical control was high at silver tip to green tip stage (80%) and fruit let pea size stage (78%) and medium adoption was observed at pink bloom (bud) stage (74%), petal fall stage (74%) walnut size apple stage (70%) on Apple Scab similarly, the extent of adoption was low (45%) for mechanical and no chemical control measures under clean cultivation. In case of San Jose Scale the farmers adoption level regarding name of chemical, its dose, quantity of water required per acre for preparing spray solution and time of spray at late dormant spray, (feb, March) was high (80%). The findings will help to improve the level of farmers’ knowledge to increase apple production in Kashmir valley

    Clustering of star-forming galaxies detected in mid-infrared with the Spitzer wide-area survey

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    We discuss the clustering properties of galaxies with signs of ongoing star formation detected by the Spitzer Space Telescope at 24mum band in the SWIRE Lockman Hole field. The sample of mid-IR-selected galaxies includes ~20,000 objects detected above a flux threshold of S24mum=310muJy. We adopt optical/near-IR color selection criteria to split the sample into the lower-redshift and higher-redshift galaxy populations. We measure the angular correlation function on scales of theta=0.01-3.5 deg, from which, using the Limber inversion along with the redshift distribution established for similarly selected source populations in the GOODS fields (Rodighiero et al. 2010), we obtain comoving correlation lengths of r0=4.98+-0.28 h^-1 Mpc and r0 =8.04+-0.69 h^-1 Mpc for the low-z (=0.7) and high-z (=1.7) subsamples, respectively. Comparing these measurements with the correlation functions of dark matter halos identified in the Bolshoi cosmological simulation (Klypin et al. 2011}, we find that the high-redshift objects reside in progressively more massive halos reaching Mtot>3e12 h^-1 Msun, compared to Mtot>7e11 h^-1 Msun for the low-redshift population. Approximate estimates of the IR luminosities based on the catalogs of 24mum sources in the GOODS fields show that our high-z subsample represents a population of "distant ULIRGs" with LIR>10^12Lsun, while the low-z subsample mainly consists of "LIRGs", LIR~10^11Lsun. The comparison of number density of the 24mum selected galaxies and of dark matter halos with derived minimum mass Mtot shows that only 20% of such halos may host star-forming galaxies.Comment: 15 pages, 12 figure

    Psychometric Properties and Validation of the Arabic Academic Performance Rating Scale

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    To validate the Arabic version of Academic Performance Rating Scale. Method. Translation and test-retest reliability were computed. Exploratory factor analysis and Rasch analysis were conducted to report on the validity. EFA factor structures were evaluated using a Scree plot and the standard multiple criteria included eigenvalue greater than 1. Average measures and step measures were ordered and themean-square outfit statistic for each category was also evaluated. Results. Cronbach’s Alpha value of 0.90 was obtained. No differences across category of educational levels were seen
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