Search results for "RAM"
showing 10 items of 35643 documents
Gaia -ESO Survey: Analysis of pre-main sequence stellar spectra
2015
This paper describes the analysis of UVES and GIRAFFE spectra acquired by the Gaia-ESO Public Spectroscopic Survey in the fields of young clusters whose population includes pre-main sequence (PMS) stars. Both methods that have been extensively used in the past and new ones developed in the contest of the Gaia-ESO survey enterprise are available and used. The internal precision of these quantities is estimated by inter-comparing the results obtained by such different methods, while the accuracy is estimated by comparison with independent external data, like effective temperature and surface gravity derived from angular diameter measurements, on a sample of benchmarks stars. Specific strategi…
Non-destructive automatic determination of aspect ratio and cross-sectional properties of fibres
2015
A novel method for computerised estimation of the aspect ratio distribution and various cross-sectional geometrical properties of fibres in short-fibre reinforced composites is proposed. The method, based on X-ray micro-computed tomography, is non-destructive and does not require user intervention. Based on results on specially fabricated model material, the accuracy and precision of the method seems adequate. The method is applied in analysing a manufacturing process of wood fibre reinforced thermoplastic composite. The results indicate a significant decrease of the aspect ratio of fibres during the processing steps. Finally, the feasibility of the method is assessed by estimating paramete…
Accurate estimation of retinal vessel width using bagged decision trees and an extended multiresolution Hermite model.
2012
We present an algorithm estimating the width of retinal vessels in fundus camera images. The algorithm uses a novel parametric surface model of the cross-sectional intensities of vessels, and ensembles of bagged decision trees to estimate the local width from the parameters of the best-fit surface. We report comparative tests with REVIEW, currently the public database of reference for retinal width estimation, containing 16 images with 193 annotated vessel segments and 5066 profile points annotated manually by three independent experts. Comparative tests are reported also with our own set of 378 vessel widths selected sparsely in 38 images from the Tayside Scotland diabetic retinopathy scre…
Optimised procedures for the reversed-phase liquid chromatographic analysis of formulations containing tricyclic antidepressants.
2003
The chromatographic behaviour (retention, selectivity, peak shape and resolution) of seven tricyclic antidepressants (TCAs), amitryptiline, clomipramine, doxepin, imipramine, maprotiline, nortryptiline and trimipramine, was examined. Conventional unendcapped Cs and C18 columns and an endcapped XTerra MS C18 column recommended for the analysis of basic compounds were used together with acetonitrile-water and micellar sodium dodecylsulfate (SDS)-pentanol mobile phases. The two best combinations were XTerra C18/acetonitrile, which yielded the largest efficiencies and resolution, and C8/SDS-pentanol, which eliminated the peak tails that were still observed with the XTerra C18 column. Both the s…
Thermal stability of transition alumina nanocrystals with different microstructures
2018
Abstract The preparation of well-crystallized boehmite nanoparticles with different morphologies, encompassing from aciculae or rods of 320, 150 and 70 nm of length to platelets of 50 nm in diameter, allowed a comparative study of their respective thermal evolutions as alumina precursors. Static thermal treatments of boehmite nanocrystals at 600, 1000 and 1200 °C and a dynamic, in situ synchrotron study between 100 and 1000 °C revealed that original boehmite microstructures, i.e. size and shape of the nanoparticles, were kept not only in γ-Al 2 O 3 but also in transitional aluminas up to 1000 °C. Specifically, at that temperature, acicular samples presented θ-Al 2 O 3 structure, while in pl…
Mechanism of crystallization of fast fired mullite-based glass–ceramic glazes for floor-tiles
2006
Abstract The mechanism of crystallization from a B 2 O 3 -containing glass, with composition based in the CaO–MgO–Al 2 O 3 –SiO 2 system, to a glass–ceramic glaze was studied by different techniques. Glass powder pellets were fast heated, simulating current industrial tile processing methods, at several temperatures from 700 to 1200 °C with a 5 min hold. Microstructural study by field emission scanning electron microscopy revealed that a phase separation phenomenon occurred in the glass, which promoted the onset of mullite crystallization at 900 °C. The amount of mullite in the glass heated between 1100 and 1200 °C was around 20 wt%, as determined by Rietveld refinement. The microstructure …
Effect of boron oxide on the microstructure of mullite-based glass-ceramic glazes for floor-tiles in the CaO–MgO–Al2O3–SiO2 system
2006
Abstract The effect of increasing replacement of Al2O3 by B2O3 in a parent glass on the sintering and further crystallization of mullite was investigated. The composition of the parent glass was chosen in the mullite primary phase field of the CaO–MgO–Al2O3–SiO2 quaternary system. Glass powder pellets were heated under standard (10 °C/min and 2 h of hold time) and fast heatings (25 °C/min and 5 min of hold time) at different temperatures from 700 to 1190 °C. Sintering of B2O3-containing glasses took place in the range between 850 and 1050 °C. X-ray diffraction results showed that mullite formed as unique crystalline phase for glasses containing amounts of B2O3 larger than 6 wt%. For lower a…
Drug resistance patterns of bacteria isolated from patients with nosocomial pneumonia at Tehran hospitals during 2009-2011
2013
Introduction: Nosocomial pneumonia remains an important cause of mortality and morbidity worldwide. Surveillance programs play an important role in the identification of common etiologic agents and local patterns of antimicrobial resistance. Methodology: In this study we determined the frequency and antimicrobial susceptibility of pathogens isolated from patients with nosocomial pneumonia during 2009 to 2011. Results: A total of 642 bacteria were isolated from 516 suspected samples. Acinetobacter baumannii (21.1%, n = 136), was the commonest isolated pathogen followed by Pseudomonas aeruginosa (17.4%, n = 112) , Staphylococcus aureus (15.8%, n = 102) and enterococci (8.4% n = 54). The most …
High susceptibility of MDR and XDR Gram-negative pathogens to biphenyl-diacetylene-based difluoromethyl-allo-threonyl-hydroxamate LpxC inhibitors
2016
International audience; Inhibitors of uridine diphosphate-3-O-(R-3-hydroxymyristoyl)-N-acetylglucosamine deacetylase (LpxC, which catalyses the first, irreversible step in lipid A biosynthesis) are a promising new class of antibiotics against Gram-negative bacteria. The objectives of the present study were to: (i) compare the antibiotic activities of three LpxC inhibitors (LPC-058, LPC-011 and LPC-087) and the reference inhibitor CHIR-090 against Gram-negative bacilli (including MDR and XDR isolates); and (ii) investigate the effect of combining these inhibitors with conventional antibiotics.MethodsMICs were determined for 369 clinical isolates (234 Enterobacteriaceae and 135 non-fermentati…
Acoustic characterization of the ancient theatre at Syracuse
2008
The ancient theatre at Syracuse, the largest open air theatre in Sicily, experienced many structural changes along its history. Today its very renowned drama festival attracts visitors from all the world that fill the entire cavea: customized seats accomodation and a prominent stage play an important role in the theatre acoustics. Because no data were available in literature on its acoustical perfomance a measurement session was carried out by our team in the framework of a wide research project on ancient theatres acoustics in the modern use. From data recorded "room criteria" parameters have been evaluated together with spectral analysis in order to gain a deeper information on the acoust…