1,502 research outputs found

    Coreference detection of low quality objects

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    The problem of record linkage is a widely studied problem that aims to identify coreferent (i.e. duplicate) data in a structured data source. As indicated by Winkler, a solution to the record linkage problem is only possible if the error rate is sufficiently low. In other words, in order to succesfully deduplicate a database, the objects in the database must be of sufficient quality. However, this assumption is not always feasible. In this paper, it is investigated how merging of low quality objects into one high quality object can improve the process of record linkage. This general idea is illustrated in the context of strings comparison, where strings of low quality (i.e. with a high typographical error rate) are merged into a string of high quality by using an n-dimensional Levenshtein distance matrix and compute the optimal alignment between the dirty strings. Results are presented and possible refinements are proposed

    Stable and Metastable vortex states and the first order transition across the peak effect region in weakly pinned 2H-NbSe_2

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    The peak effect in weakly pinned superconductors is accompanied by metastable vortex states. Each metastable vortex configuration is characterized by a different critical current density J_c, which mainly depends on the past thermomagnetic history of the superconductor. A recent model [G. Ravikumar, et al, Phys. Rev. B 61, R6479 (2000)] proposed to explain the history dependent J_c postulates a stable state of vortex lattice with a critical current density J_c^{st}, determined uniquely by the field and temperature. In this paper, we present evidence for the existence of the stable state of the vortex lattice in the peak effect region of 2H-NbSe_2. It is shown that this stable state can be reached from any metastable vortex state by cycling the applied field by a small amplitude. The minor magnetization loops obtained by repeated field cycling allow us to determine the pinning and "equilibrium" properties of the stable state of the vortex lattice at a given field and temperature unambiguously. The data imply the occurence of a first order phase transition from an ordered phase to a disordered vortex phase across the peak effect.Comment: 20 pages, 10 figures. Corresponding author: S. Ramakrishna

    Effect of sulphur, zinc and boron on the growth and yield enhancement of sunflower (Helianthus annuus L.)

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    Oilseed crops grown in different types of soil experience nutrient deficiency, especially sulphur, zinc and boron, which affect crop productivity. To tackle it, nutrient management practices must be streamlined to avoid improper fertilizations and deterioration of soil health. With this background, experimental trials were conducted to study the effect of sulphur, zinc and boron application on the growth, yield components and yield of hybrid sunflower at AyanAthur village, Ariyalur district (TN) during the summer seasons of 2016 and 2017. The experiments were laid out in Randomized Block Design (RBD) with three replications. The growth components of sunflower (plant height, leaf area index, dry matter production, leaf area duration (LAD) and growth analysis parameters such as crop growth rate (CGR), relative growth rate(RGR), net assimilation rate(NAR) and chlorophyll content, yield components and seed yield were significantly (level of significance P>0.05) influenced by foliar application of 0.5% Zn on bud initiation stage and seed formation stage and B @ 0.3% on bud initiation stage and ray floret formation stage along with S(sulphur) @ 40 kg ha-1 and RDF(recommended dose of fertilizers) as a soil application. Growth and yield parameters responded very little with the RDF alone. From both experimental results, we found that foliar application of Zn @ 0.5%and B @ 0.3% along with S @ 40 kg ha-1 and RDF recorded the highest percentage of dry matter production (44.4%), number of filled seeds (30.1%) and yield (32.4%) of hybrid sunflower

    Real-Time Vector Automata

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    We study the computational power of real-time finite automata that have been augmented with a vector of dimension k, and programmed to multiply this vector at each step by an appropriately selected kĂ—kk \times k matrix. Only one entry of the vector can be tested for equality to 1 at any time. Classes of languages recognized by deterministic, nondeterministic, and "blind" versions of these machines are studied and compared with each other, and the associated classes for multicounter automata, automata with multiplication, and generalized finite automata.Comment: 14 page

    Integrated nutrient management - promising way to reduce carbon dioxide and methane emission in flooded rice ecosystem: A review

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    Climate change is an inevitable ruling issue caused by the increasing concentration of greenhouse gases (GHG’s) in the atmosphere worldwide. It will have a considerable impact on agriculture and its related fields like live stocks and fisheries. In India, the main sectors contributing to these emissions are industry, agriculture and waste, with a total emission of 334 MT CO2 eq. Besides, the major sources in agriculture are enteric fermentation (63.4%), rice cultivation (20.9%), agricultural soils (13.0%), manure management (2.4%) and on-field burning is the crop residue (2.0%). Thus, the crop productivity sector (rice cultivation, soil and field burning of crop residues) contributes 35.9% to the total emission from agriculture. Therefore, reducing GHG emissions and enhancing the C sequestration in soil and biomass has become challenging. However, the total GHG’s emission from all sectors of the country has decreased from 33% in 1970 to 18% in 2010. Cutting off GHGs emission from agriculture can be achieved by sequestering C and reducing methane emissions(CH4) and carbon dioxide(CO2) through various soil and crop management strategies. Integrated nutrient management (INM) practice ensures the Soil –plant –atmospheric continuum (SPAC) in a  promising way, reducing the GHGs emission by sequestering more carbon to soil than emissions. A studious prominent INM solution can be identified to develop a mitigation strategy that helps in climate change adaptation and sustains soil health through soil carbon sequestration

    Green facile synthesis of Ag-doped ZnO nanoparticles from Gymnema sylvestre leaf extract and investigation of their Antibacterial activity

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    The unique characteristics of the green synthesis pathway have opened the way for a new field of scientific investigation. The current study used green chemistry methodologies to produce pure zinc oxide (ZnO) (G1) and silver doped zinc oxide (Ag doped ZnO) (G2) nanoparticles (NPs) using Gymnema sylvestre (G. sylvestre) leaf extract as a reducing as well as capping agent. XRD, FESEM, EDAX, and FT-IR investigations were used to investigate the structural characterization of G1 and G2 NPs. The UV–Vis and PL analyses were used to examine the optical characteristics. The results clearly reveal that the leaf extract is the best possible stabilizing agent for the manufacture of G1 and G2 NPs, and that the generated nanoparticles operate as potent microbial agents, inhibiting the growth of a variety of dangerous microbes. Due to their eco–friendly and non–toxic compatibility, the prepared G1 and G2 NPs can be employed for therapeutic and other purposes

    Investigation of the morphological, optical and antimicrobial properties of Nd-doped ZnO nanoparticles using Hemidesmus indicus (L.) R. Br. Root extracts

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    In the current study, we present a low-cost, novel, and straightforward method for the biopreparation of zinc oxide nanoparticles (ZnO NPs) and neodymium (Nd3+) doped ZnO NPs using extracts of Hemidesmus indicus (H. indicus) (L.) R. Br. root like a sustainable reducing as well as coating agent. Rietveld’s analysis of the XRD data showed that ZnO and Nd3+ doped ZnO NPs have a hexagonal wurtzite crystalline level. The morphological representation of synthesized NPs was analyzed by FESEM and chemical composition by EDAX. The different vibrational frequencies were assigned for the FT-IR spectra. The Optical behaviour of the prepared NPs be present studies by UV–visible spectroscopy. Moreover, this study concludes the antimicrobial efficiency of the synthesized NPs opposed to standard and clinical strains of Staphylococcus aureus (gram-positive) and Klebsiella pneumoniae (gram-negative) bacterial strains using the well diffusion method

    A study of supercooling of the disordered vortex phase via minor hysteresis loops in 2H-NbSe_2

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    We report on the observation of novel features in the minor hysteresis loops in a clean crystal of NbSe_2 which displays a peak effect. The observed behavior can be explained in terms of a supercooling of the disordered vortex phase while cooling the superconductor in a field. Also, the extent of spatial order in a flux line lattice formed in ascending fields is different from (and larger than) that in the descending fields below the peak position of the peak effect; this is attributed to unequal degree of annealing of the state induced by a change of field in the two cases.Comment: 5 pages of text + 6 figures, submitted to Phys. Rev.
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