1,622 research outputs found

    An efficient strategy for the collection and storage of large volumes of data for computation

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    In recent years, there has been an increasing amount of data being produced and stored, which is known as Big Data. The social networks, internet of things, scientific experiments and commercial services play a significant role in generating a vast amount of data. Three main factors are important in Big Data; Volume, Velocity and Variety. One needs to consider all three factors when designing a platform to support Big Data. The Large Hadron Collider (LHC) particle accelerator at CERN consists of a number of data-intensive experiments, which are estimated to produce a volume of about 30 PB of data, annually. The velocity of these data that are propagated will be extremely fast. Traditional methods of collecting, storing and analysing data have become insufficient in managing the rapidly growing volume of data. Therefore, it is essential to have an efficient strategy to capture these data as they are produced. In this paper, a number of models are explored to understand what should be the best approach for collecting and storing Big Data for analytics. An evaluation of the performance of full execution cycles of these approaches on the monitoring of the Worldwide LHC Computing Grid (WLCG) infrastructure for collecting, storing and analysing data is presented. Moreover, the models discussed are applied to a community driven software solution, Apache Flume, to show how they can be integrated, seamlessly

    Double-spiral magnetic structure of the Fe/Cr multilayer revealed by nuclear resonance scattering

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    We have studied the magnetization depth profiles in a [57Fe(dFe)/Cr(dCr)]x30 multilayer with ultrathin Fe layers and nominal thickness of the chromium spacers dCr 2.0 nm using nuclear resonance scattering of synchrotron radiation. The presence of a broad pure-magnetic half-order (1/2) Bragg reflection has been detected at zero external field. The joint fit of the reflectivity curves and Mossbauer spectra of reflectivity measured near the critical angle and at the "magnetic" peak reveals that the magnetic structure of the multilayer is formed by two spirals, one in the odd and another one in the even iron layers, with the opposite signs of rotation. The double-spiral structure starts from the surface with the almost antiferromagnetic alignment of the adjacent Fe layers. The rotation of the two spirals leads to nearly ferromagnetic alignment of the two magnetic subsystems at some depth, where the sudden turn of the magnetic vectors by ~180 deg (spin-flop) appears, and both spirals start to rotate in opposite directions. The observation of this unusual double-spiral magnetic structure suggests that the unique properties of giant magneto-resistance devices can be further tailored using ultrathin magnetic layers.Comment: 9 pages, 3 figure

    T134 Allelic imbalance and epigenetic changes as a marker of tumor spreading into the adjacent tissue

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    Non-small cell lung cancer (NSCLC) is characterized by multiple genetic alterations such as loss of heterozygosity (LOH), microsatellite instability (MSI), promoter hypermethylation and changes of miRNA expression. According to a field cancerization (FC) phenomenon the adjacent histologically normal tissue plays a role in tumor progression by triggering the transformation process.The aim of the study was the analysis of genetic alterations in tumor and adjacent tissue to determine the FC size and to reveal associations with clinico-morphological features of patients.The study group included 135 patients with NSCLC. From each patient 4 FFPE samples were analyzed: tumor, adjacent normal lung tissue at 2, 5, 10cm. LOH/MSI analysis was evaluated by PCR using 7 microsatellite loci. Promoter hypermethylation in genes RASSF1A FHIT, DAPK1, CDH1, CD44, TIMP3, MGMT was investigated by methyl-sensitive PCR. The expression levels of miRNAs let-7a, miR-155, miR-205 were measured by real-time PCR.Our results demonstrated that LOH/MSI occurs only in tumor while promoter hypermethylation occurs also in adjacent tissue at 2, 5cm, but not at 10cm. The downregulation of let-7a, miR-155 in adjacent tissue is lower than in tumor. The levels of investigated miRNAs in adjacent tissue vary depending on tumor differentiation – in patients with differentiated tumors it is higher than in the group with poorly differentiated tumors.We postulate that FC size in NSCLC is at least 5cm from tumor and includes only epigenetic but not structural (LOH/MSI) alterations. The evaluation of epigenetic changes in adjacent tissue (e.g., surgical margins) can potentially be used for postsurgical prognosis

    In situ FT-IR investigation of the reduction of NO with CO over Au/CeO2-Al2O3 catalyst in the presence and absence of H-2

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    Cataloged from PDF version of article.he NO + CO + H-2 reaction over CeO2, Au/CeO2 (3 wt% Au), Au/CeO2-Al2O3 (2.9 wt% Au, 20 wt% Al2O3) and CeO2-Al2O3 mixed support prepared by co-precipitation has been Studied by FT-IR spectroscopy at elevated temperatures. Formation of NCO species has been detected on all of the samples. The presence of metallic gold is not necessary for the generation of the isocyanates on ceria and the mixed ceria-alumina support. The NCO species are produced by a process involving the dissociation of NO on the oxygen vacancies of the support, followed by the reaction between N atoms lying oil the surface and CO molecules. Gold plays an important role in the modification of ceria leading to Ce3+ and oxygen vacancies formation, and causes significant lowering of the reduction temperature of CeO2 and CeO2-Al2O3 enhancing the reducibility of ceria surface layers. The role of H-2 is to keep the surface reduced during the course of the reaction. The onset temperature, at which the interaction between the surface isocyanates and No begins, is low (100 degrees C). This explains the high activity of the Au/CeO2-Al2O3 catalyst with 100% selectivity in the reduction of NO by CO at low temperature (200 degrees C) and in the presence of H-2 (C) 2008 Elsevier B.V. All rights reserve

    Clustering in light nuclei in fragmentation above 1 A GeV

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    The relativistic invariant approach is applied to analyzing the 3.3 A GeV 22^{22}Ne fragmentation in a nuclear track emulsion. New results on few-body dissociations have been obtained from the emulsion exposures to 2.1 A GeV 14^{14}N and 1.2 A GeV 9^{9}Be nuclei. It can be asserted that the use of the invariant approach is an effective means of obtaining conclusions about the behavior of systems involving a few He nuclei at a relative energy close to 1 MeV per nucleon. The first observations of fragmentation of 1.2 A GeV 8^{8}B and 9^{9}C nuclei in emulsion are described. The presented results allow one to justify the development of few-body aspects of nuclear astrophysics.Comment: 7 pages, 8 figures, 3 tables, Nuclear Physics in Astrophysics-2, 16-20 May, 2005 (ATOMKI), Debrecen, Hungar
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