2,317 research outputs found

    A Survey and Evaluation of Edge Detection Operators: Application to Text Recognition

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    Edge detection, especially in image processing occupies a special position. How to accurately extract the edge information of object in images has been the hot research. One of the main objectives of image analysis is to extract the dominating information. Segmentation of image is defined as being major step in image processing that extracts and describes the presence of significant object in a scene, often in the form of region or edges. This paper describes several edge detection operators like Sobel, Prewitt, Canny, Roberts, Zero threshold and emergence of combination of different spatial edge detection method, and its matlab simulation studies and comparative analysis

    Reaction of sulphate radical anion (SO<SUB>4</SUB><SUP>&#8226;-</SUP>) with hydroxy- and methyl-substituted pyrimidines: a pulse radiolysis study

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    Reactions of sulphate radical anion (SO4&#8226;-) with 4,6-dihydroxy-2-methyl pyrimidine (DHMP), 2,4-dimethyl-6-hydroxy pyrimidine (DMHP), 6-methyl uracil (MU) and 5,6-dimethyl uracil (DMU) have been studied by pulse radiolysis at pH 3 and at pH 10. The transient intermediate spectra were compared with those from the reaction of hydroxyl radical (&#8226;OH). It is proposed that SOSO4&#8226;- produces radical cations of these pyrimidines in the initial stage. These radical cations are short-lived except in the case of DMHP where a relatively longer lived radical cation is proposed to be formed. When there is a hydrogen atom attached to the N(1) or N(3) position, a deprotonation from these sites is highly favored. When there is no hydrogen attached to these sites, deprotonation from a substituted methyl group is favored. At acidic pH, deprotonation from nitrogen is observed for DHMP, MU and DMU. At basic pH, the radical cation reacts with OH- leading to the formation of OH adducts

    Reaction of oxide radical ion (O<SUP>&#8226;-</SUP>) with substituted pyrimidines

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    Pulse radiolysis technique has been used to investigate the reaction of oxide radical ion (O&#8226;-) with 4,6-dihydroxy-2-methyl pyrimidine (DHMP), 2,4-dimethyl-6-hydroxy pyrimidine (DMHP), 5,6-dimethyl uracil (DMU) and 6-methyl uracil (MU) in strongly alkaline medium. The second-order rate constants for the reaction of O&#8226;- with these compounds are in the range 2-5 &#215; 108 dm3 mol-1 s-1. The transient absorption spectra obtained with DHMP have two maxima at 290 and 370 nm and with DMHP have maxima at 310 and 470 nm. The transient spectrum from DMU is characterized by its absorption maxima at 310 and 520 nm and that of MU by its single maximum at 425 nm. The intermediate species were found to react with N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD) with high G(TMPD&#8226;+) values ranged between 3.9 &#215; 10-7 molJ-1 and 4.8 &#215; 10-7 molJ-1. These radicals undergo decay by second-order kinetics (2k/&#949; = 1.0-1.7 &#215; 106 s-1). The reaction of O&#8226;- with the selected pyrimidines is proposed to proceed through a hydrogen abstraction from the methyl group forming allyl type radicals. These are mainly oxidizing radicals and hence readily undergo electron transfer reactions with TMPD

    Moving To The Cloud: Transitioning From Client-Server To Service Architecture

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    This paper makes the case that the traditional three-tier client-server architecture requires a major overhaul to address the changing and rapidly increasing information processing and services needs of consumers. Revisions to the conventional architecture model are suggested and two examples of information systems applications are discussed to illustrate how the new information service architecture fits into the realm of future systems development

    Kinase profiling of liposarcomas using RNAi and drug screening assays identified druggable targets.

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    BackgroundLiposarcoma, the most common soft tissue tumor, is understudied cancer, and limited progress has been made in the treatment of metastatic disease. The Achilles heel of cancer often is their kinases that are excellent therapeutic targets. However, very limited knowledge exists of therapeutic critical kinase targets in liposarcoma that could be potentially used in disease management.MethodsLarge RNAi and small-molecule tyrosine kinase inhibitor screens were performed against the proliferative capacity of liposarcoma cell lines of different subtypes. Each small molecule inhibitor was either FDA approved or in a clinical trial.ResultsScreening assays identified several previously unrecognized targets including PTK2 and KIT in liposarcoma. We also observed that ponatinib, multi-targeted tyrosine kinase inhibitor, was the most effective drug with anti-growth effects against all cell lines. In vitro assays showed that ponatinib inhibited the clonogenic proliferation of liposarcoma, and this anti-growth effect was associated with apoptosis and cell cycle arrest at the G0/G1 phase as well as a decrease in the KIT signaling pathway. In addition, ponatinib inhibited in vivo growth of liposarcoma in a xenograft model.ConclusionsTwo large-scale kinase screenings identified novel liposarcoma targets and a FDA-approved inhibitor, ponatinib with clear anti-liposarcoma activity highlighting its potential therapy for treatment of this deadly tumor

    An evolved disk surrounding the massive main sequence star MWC 297?

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    We present the results of the interferometric observations of the circumstellar disk surrounding MWC 297 in the continuum at 230 GHz (1.3 mm) and in the (J=2-1) rotational transitions of 12^{12}CO,13^{13}CO and C18^{18}O using the Submillimeter Array. At a distance of 250 pc, MWC 297 is one of the closest, young massive stars (M⋆_{\star} ∼\sim10 M⊙_{\odot}) to us. Compact continuum emission is detected towards MWC 297 from which we estimate a disk mass (gas+dust) of 0.07 M⊙_{\odot} and a disk radius of ≤\le 80 AU. Our result demonstrates that circumstellar disks can survive around massive stars well into their main sequence phase even after they have become optically visible. Complementing our observations with the data compiled from the literature, we find the submm dust opacity index β\beta to be between 0.1 and 0.3. If the emission is optically thin, the low value of β\beta indicates the presence of relatively large grains in the disk, possibly because of grain growth. We do not detect any CO emission associated with the continuum source. We argue that the 13^{13}CO emission from the disk is likely optically thin, in which case, we derive an upper limit to the gas mass which implies significant depletion of molecular gas in the disk. The mass of this disk and the evolutionary trends observed are similar to those found for intermediate mass Herbig Ae stars and low mass T Tauri stars.Comment: 4 pages, 3 Figures, accepted for publication in ApJ

    On characteristic initial data for a star orbiting a black hole

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    We take further steps in the development of the characteristic approach to enable handling the physical problem of a compact self-gravitating object, such as a neutron star, in close orbit around a black hole. We examine different options for setting the initial data for this problem and, in order to shed light on their physical relevance, we carry out short time evolution of this data. To this end we express the matter part of the characteristic gravity code so that the hydrodynamics are in conservation form. The resulting gravity plus matter relativity code provides a starting point for more refined future efforts at longer term evolution. In the present work we find that, independently of the details of the initial gravitational data, the system quickly flushes out spurious gravitational radiation and relaxes to a quasi-equilibrium state with an approximate helical symmetry corresponding to the circular orbit of the star.Comment: 20 pages, 10 figure

    Evaluation of Solanum species and eggplant cultivated varieties for bacterial wilt resistance

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    Bacterial wilt caused by Ralstonia solanacearum is one of the major diseases in Solanum species including cultivated Eggplant (Solanum melongena L.). Bacterial wilt (BW) disease management in eggplant is difficult due to high survival rate of pathogen in soil and chemical application is not eco-friendly. The best way to avoid bacterial wilt in eggplant is using disease-resistant varieties. However, only a limited number of bacterial wilt resistant varieties are available and, there is a necessity to identify and/or develop new resistant varieties. In the current study, wild Solanum species, and eggplant cultivated varieties were evaluated against Ralstonia solanacearum, and disease incidence was recorded. The cultivated varieties IIHR-108, Pusa Purple Long and Rampur Local were identified as susceptible, whereas, IIHR-7 and CARI-1 were identified as resistant to bacterial wilt. These resistant wild and cultivated varieties can be used as a root-stock in bacterialwilt disease resistant breeding programmes

    Black Hole Data via a Kerr-Schild Approach

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    We present a new approach for setting initial Cauchy data for multiple black hole spacetimes. The method is based upon adopting an initially Kerr-Schild form of the metric. In the case of non-spinning holes, the constraint equations take a simple hierarchical form which is amenable to direct numerical integration. The feasibility of this approach is demonstrated by solving analytically the problem of initial data in a perturbed Schwarzschild geometry.Comment: 13 pages, RevTeX forma
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