1,202 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

    Effect of different phosphorus sources applied with phosphate solubilizing bacteria on bio-geochemical properties and phosphorus release pattern in vertisol

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    Various phosphorus (P) fertilizers are used for crop production in different types of soil. But there is a knowledge gap in choosing the right source and form of  P fertilizers to enhance the applied fertilizer use efficiency. An experiment was taken to identify the best phosphorus source and its effectiveness as a source of P in vertisol to unravel this problem of selecting suitable P fertilizer. With this background, an incubation experiment was conducted under laboratory condition to determine the phosphorus release pattern of different P sources [Single Super Phosphate (SSP), Rock Phosphate (RP), Diammonium Phosphate (DAP), Nano phosphate (Nano P), Phosphocompost (PC)] applied with phosphate solubilizing bacteria (PSB) and their influence on biogeochemical properties in vertisol.  Experimental results emphasized that P release from different sources was influenced by soil pH, electrical conductivity (EC), cation exchange capacity (CEC), soil organic carbon (SOC), and microbial population. Applied P sources significantly(p=0.05) influenced the CEC, SOC, and microbial population except for soil pH and Ec. The maximum release in available P was obtained at 30 and 60 days after incubation with SSP +PSB  (35.8 and 40.1 mg kg-1) and Nano P + PSB (33.9 and 38.6 mg kg-1) applied treatments, respectively.Whereas at 90 days after incubation Nano P + PSB (42.3 mg kg-1) and Phosphocompost + PSB (40.4 mg kg-1) treatments recorded the maximum P availability and minimum P (15.2, 13.9 and 11.8 mg kg -1) release was noticed in the control treatment throughout the period of incubation. It was evident that SSP or Nano P along with PSB application might be the best P source for Vertisol

    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

    Inorganic Water Repellent Coatings for Thermal Protection Insulation on an Aerospace Vehicle

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    The objective of this research was two-fold: first, to identify and test inorganic water-repellent materials that would be hydrophobic even after thermal cycling to temperatures above 600 C and, second, to develop a model that would link hydrophobicity of a material to the chemical properties of its constituent atoms. Four different materials were selected for detailed experimental study, namely, boron nitride, talc, molybdenite, and pyrophyllite, all of which have a layered structure made up of ionic/covalent bonds within the layers but with van der Waals bonds between the layers. The materials tested could be considered hydrophobic for a nonporous surface but none of the observed contact angles exceeded the necessary 90 degrees required for water repellency of porous materials. Boron nitride and talc were observed to retain their water-repellency when heated in air to temperatures that did not exceed 800 C, and molybdenite was found to be retain its hydrophobicity when heated to temperatures up to 600 C. For these three materials, oxidation and decomposition were identified to be the main cause for the breakdown of water repellency after repeated thermal cycling. Pyrophyllite shows the maximum promise as a potential water-repellent inorganic material, which, when treated initially at 900 C, retained its shape and remained hydrophobic for two thermal cycles where the maximum retreatment temperature is 900 C. A model was developed for predicting materials that might exhibit hydrophobicity by linking two chemical properties, namely, that the constituent ions of the compound belong to the soft acid-base category and that the fractional ionic character of the bonds be less than about 20 percent

    Preparation of water hyacinth-based phosphocompost and its evaluation against certain phosphorus fertilizers along with phosphate solubilizing bacteria on P availability, uptake and rice productivity

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    Phosphorus (P) deficiency in soil limits crop yields and can be managed by P fertilizers. But mere applying P fertilizers alone may not be effective in justifying its bioavailability. At present global P reserves are declining in an increasing way which urges us to find out alternatives. Thus, the present work was taken to prepare phosphocompost using water hyacinth (Eichhornia crassipes) as feedstock, termite, and normal soil as bulking agents cum decomposers and enriched with single super phosphate. The effect of phosphocompost on rice(var.ADT-43) productivity, P availability and uptake was evaluated by comparing various P fertilizers (single super phosphate, rock phosphate, di-ammonium phosphate, nano phosphate) combined with or without phosphate solubilizing bacteria (PSB). The experiment was laid out in a completely randomized design with seven treatments including absolute control and replicated thrice. Phosphocompost produced with water hyacinth and termite soil microbes come with superior quality and early maturity compared to normal soil. Pot culture study results revealed that rice growth, yield, P availability and uptake were significantly (p<0.05) higher with SSP + PSB, and Nano phosphate +PSB treated plants, followed by Phosphocompost + PSB. The cost of P fertilizer (Rs/ha) related to yield (kg/ha) was found to be significantly low with phosphocompost (Rs.1132/-) than SSP (Rs.1530/-) and Nano P (Rs.2518/-). Further, phosphocompost combined PSB helps in optimizing the P availability in a long run through P solubilization thus sustained the P uptake. The present investigation brings light to the valorization of water hyacinth as compost will be an effective and economically viable alternative for P fertilizers

    Context-dependent conformation of diethylglycine residues in peptides

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    Diethylglycine (Deg) residues incorporated into peptides can stabilize fully extended (C5) or helical conformations. The conformations of three tetrapeptides Boc-Xxx-Deg-Xxx-Deg-OMe (Xxx = Gly, GD4; Leu, LD4 and Pro, PD4) have been investigated by NMR. In the Gly and Leu peptides, NOE data suggest that the local conformations at the Deg residues are fully extended. Low temperature coefficients for the Deg(2) and Deg(4) NH groups are consistent with their inaccessibility to solvent, in a C5 conformation. NMR evidence supports a folded β-turn conformation involving Deg(2)-Gly(3), stabilized by a 4→1 intramolecular hydrogen bond between Pro(1) CO and Deg(4) NH in the proline containing peptide (PD4). The crystal structure of GD4 reveals a hydrated multiple turn conformation with Gly(1)-Deg(2) adopting a distorted type II/II′ conformation, while the Deg(2)-Pro(3) segment adopts a type III/III′ structure. A lone water molecule is inserted into the potential 4 → 1 hydrogen bond of the Gly(1)-Deg(2) β-turn

    Exact Solution of Return Hysteresis Loops in One Dimensional Random Field Ising Model at Zero Temperature

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    Minor hysteresis loops within the main loop are obtained analytically and exactly in the one-dimensional ferromagnetic random field Ising-model at zero temperature. Numerical simulations of the model show excellent agreement with the analytical results
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