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See detailImproved Finite Element Solvers for the Helmholtz Equation at High Frequencies
Geuzaine, Christophe ULg

Scientific conference (2012, March 29)

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See detailImproved first order moment method for determination of mass-loss rates
Hutsemekers, Damien ULg; Surdej, Jean ULg

in Bianchi, L.; Gilmozzi, R. (Eds.) Mass outflows from stars and galactic nuclei; Proceedings of the Second Torino Workshop (1988)

The first order moment of P Cygni line profiles has been computed for the case of doublets and subordinate line transitions. This improved method can be used for deriving more accurate mass-loss rates of ... [more ▼]

The first order moment of P Cygni line profiles has been computed for the case of doublets and subordinate line transitions. This improved method can be used for deriving more accurate mass-loss rates of planetary nebula nuclei, broad absorption line quasars, etc. [less ▲]

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See detailImproved Forwarding Architecture and Resource Management for Multi-Core Software Routers
Egi, Norbert; Greenhalgh, Adam; Handley, Mark et al

in NPC 2009 Proceedings (2009, October)

Recent technological advances in commodity server architectures, with multiple multi-core CPUs, integrated memory controllers, high-speed interconnects and enhanced network interface cards, provide ... [more ▼]

Recent technological advances in commodity server architectures, with multiple multi-core CPUs, integrated memory controllers, high-speed interconnects and enhanced network interface cards, provide substantial computational capacity and thus an attractive platform for packet forwarding. However, to exploit this available capacity, we need a suitable software platform that allows effective parallel packet processing and resource management. In this paper, we at first introduce an improved forwarding architecture for software routers that enhances parallelism by exploiting hardware classification and multi-queue support, already available in recent commodity network interface cards. After evaluating the original scheduling algorithm of the widely-used Click modular router, we propose solutions for extending this scheduler for improved fairness, throughput and more precise resource management. To illustrate the potential benefits of our proposal, we implement and evaluate a few key elements of our overall design. [less ▲]

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See detailImproved Four-Color Flow Cytometry Method Using Fluo-3 and Triple Immunofluorescence for Analysis of Intracellular Calcium Ion ([Ca2+]I) Fluxes among Mouse Lymph Node B- and T-Lymphocyte Subsets
Greimers, Roland ULg; Trebak, M.; Moutschen, Michel ULg et al

in Cytometry (1996), 23(3), 205-17

A visible-light, dual-laser, flow cytometric method was developed for the simultaneous analysis of intracellular ionized calcium concentration ([Ca2+]i) and three cell-surface markers (CD4, CD8, and Thy-1 ... [more ▼]

A visible-light, dual-laser, flow cytometric method was developed for the simultaneous analysis of intracellular ionized calcium concentration ([Ca2+]i) and three cell-surface markers (CD4, CD8, and Thy-1.2 antigens) by using the calcium probe fluo-3 and using R-phycoerythrin (PE), peridinin chlorophyll-alpha protein (PerCP), and allophycocyanin (APC) conjugated monoclonal antibodies (MoAbs). This improved method was used in the analysis of [Ca2+]i mobilization upon in vitro stimulation with mitogenic lectins [phytohaemagglutinin (PHA) or concanavalin A (ConA)], anti-CD3 MoAbs, or A23187 calcium ionophore in the heterogeneous lymph node cell populations from healthy C57BL/Ka mice. The present results show that the calcium responses were heterogeneous and dependent on the cellular immunophenotype, not only on lectins or anti-CD3 MoAbs stimulation, but also on the receptor-independent A23187 ionophore stimulation. An in situ fluo-3 calibration method (using A23187 and metabolic poisons in Ca2+ /EGTA buffers with known free calcium concentrations) indicated a resting [Ca2+]i in lymphocytes of 103 +/- 23 nM (mean +/- S.D.) but with significant differences between the [Ca2+]i in B cells and in all of the T-cell subsets (CD4+Thy-1+, CD4+Thy-1-, and CD8+T cells). Both the B cells and the T-cell subsets showed an increase of fluo-3 fluorescence upon in vitro stimulation with ConA or PHA, but the calcium mobilization following lectin stimulation was time delayed in all T-cell subsets. Only the T cells, including the CD4+Thy-1- subset, responded to anti-CD3 MoAbs. The percentage of responding cells upon stimulation with ConA was higher in T cells than in B cells. By contrast, PHA gave a higher response in B cells. After stimulation with different mitogens, [Ca2+]i increased in both CD4+ and CD8+ T-cell subsets. However, the percentage of responding cells was far higher in the CD4+Thy-1+ subset than in the CD4+Thy-1- or the CD8+T-cell subsets. The stimulation with A23187 ionophore induced a higher calcium response in B cells than in T cells. Interestingly, it also induced greater Ca2+ mobilization in CD4+ than in CD8+T cells. These results demonstrate the potential use of fluo-3 simultaneously with three fluorescein (FITC)-compatible fluorochromes. This technique may be useful for investigating the role of the CD4+Thy-1-T cells, a rare subset that is abnormally expanded in a murine acquired immunodeficiency syndrome (murine AIDS). [less ▲]

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See detailImproved head and neck FDG-PET imaging using segmented attenuation correction.
PAULUS, P.; HENRY, S.; HUSTINX, Roland ULg et al

in European Journal of Nuclear Medicine (1997), 24

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See detailAn improved HPLC-UV method for the simultaneous quantification of triterpenic glycosides and aglycones in leaves of Centella asiatica (L.) Urb (APIACEAE).
Rafamantanana, M. H.; Rozet, Eric ULg; Raoelison, G. E. et al

in Journal of Chromatography. B : Analytical Technologies in the Biomedical & Life Sciences (2009), 877(23), 2396-402

The simultaneous quantification of madecassoside, asiaticoside, madecassic acid and asiatic acid in Centella asiatica by HPLC-UV is proposed. Asiaticoside was used as reference for the quantification of ... [more ▼]

The simultaneous quantification of madecassoside, asiaticoside, madecassic acid and asiatic acid in Centella asiatica by HPLC-UV is proposed. Asiaticoside was used as reference for the quantification of heterosides and asiatic acid for aglycones. The evaluation of the extraction efficiency of the four molecules led to use Soxhlet extraction for 8 h. The method was validated and was found to be accurate in the concentration range of 1.0-3.0 mg/ml for asiaticoside and 0.5-2.0 mg/ml for asiatic acid with CV <3% for all investigated compounds. LOD and LOQ were, respectively, 0.0113 and 1.0 mg/ml for asiaticoside and 0.0023 and 0.5 mg/ml for asiatic acid. This method was shown to be convenient for routine analysis of samples of C. asiatica. [less ▲]

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See detailImproved IL-2 detection for determination of helper T lymphocyte precursor frequency in limiting dilution assay
Winandy, Marie ULg; Lewalle, Philippe; Deneys, Véronique et al

in Journal of Immunological Methods (1998), 215

In the context of allogeneic bone marrow transplantation, an accurate estimate of the risk of developing graft-versus-host disease GVHD. is of major interest. The pre-transplant frequency of donor’s ... [more ▼]

In the context of allogeneic bone marrow transplantation, an accurate estimate of the risk of developing graft-versus-host disease GVHD. is of major interest. The pre-transplant frequency of donor’s helper T-lymphocyte precursors HTLp. directed against host’s antigens may be helpful in predicting this risk. This technique relies on an indirect measurement of interleukin-2 IL-2. secreted by the HTLp, as assessed by the proliferation of an IL-2 dependent cell line. Many authors use the murine CTLL-2 cell line in this assay, but these cells do not respond to the presence of minute amounts of IL-2 in the culture medium, and thus do not discriminate between the absence or the presence of very low levels of IL-2. We therefore decided to compare CTLL-2 with another IL-2 dependent cell line, the murine A9.12 cell line. A comparison was made using serial dilutions of recombinant human IL-2, limiting dilutions of baby hamster kidney BHK. cells transfected with human IL-2 gene and in the context of clinical tests performed for the detection of pre-transplant HTLp. Both the sensitivity and reliability of the tests were better using A9.12. We conclude that the A9.12 cell line might be a more suitable tool for pre-transplant HTLp determinations before allogeneic bone marrow transplantation or whenever low IL-2 levels are to be measured. [less ▲]

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See detailImproved implementation and robustness study of the X-FEM for stress analysis around cracks
Béchet, Eric ULg; Minnebol, H.; Moes, N. et al

in International Journal for Numerical Methods in Engineering (2005), 64(8), 1033-1056

Numerical crack propagation schemes were augmented in an elegant manner by the X-FEM method. The use of special tip enrichment functions, as well as a discontinuous function along the sides of the crack ... [more ▼]

Numerical crack propagation schemes were augmented in an elegant manner by the X-FEM method. The use of special tip enrichment functions, as well as a discontinuous function along the sides of the crack allows one to do a complete crack analysis virtually without modifying the underlying mesh, which is of industrial interest, especially when a numerical model for crack propagation is desired. This paper improves the implementation of the X-FEM method for stress analysis around cracks in three ways. First, the enrichment strategy is revisited. The conventional approach uses a 'topological' enrichment (only the elements touching the front are enriched). We suggest a 'geometrical' enrichment in which a given domain size is enriched. The improvements obtained with this enrichment are discussed. Second, the conditioning of the X-FEM both for topological and geometrical enrichments is studied. A preconditioner is introduced so that 'off the shelf' iterative solver packages can be used and perform as well on X-FEM matrices as on standard FEM matrices. The preconditioner uses a local (nodal) Cholesky based decomposition. Third, the numerical integration scheme to build the X-FEM stiffness matrix is dramatically improved for tip enrichment functions by the use of an ad hoc integration scheme. A 2D benchmark problem is designed to show the improvements and the robustness. Copyright (c) 2005 John Wiley & Sons, Ltd. [less ▲]

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See detailImproved Implementation of the Harmonic Balance Method
Vio, Gareth Arthur; Dimitriadis, Grigorios ULg; Cooper, Jonathan Edward

in Proceedings of the 48th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference (2007, April)

Harmonic Balance (HB) methods have been applied to non-linear aeroelastic problems since the 1980s. As the computational power available to researchers has increased, so has the order of calculated HB ... [more ▼]

Harmonic Balance (HB) methods have been applied to non-linear aeroelastic problems since the 1980s. As the computational power available to researchers has increased, so has the order of calculated HB solutions. However, the computational cost of a HB solution increases with the square of the order. Additionally, the traditional Newton-Raphson, Broyden, Toeplitz Jacobian and other techniques used for the solution of the non-linear algebraic problem at the heart of the HB methodology rely on a good initial guess for the unknown coefficients. If there are many such coefficients the probability that a good guess will be available is very low and the HB scheme may well fail. In this paper a search procedure using Genetic Algorithms (GA) is introduced to evaluate the coefficients of a harmonic balance solution. It is shown that the GA can provide high quality initial guesses for the HB coefficients. The method is applied to an aeroelastic galloping-type problem. [less ▲]

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See detailImproved management practices to increase productivity of traditional cereal/pigeonpea intercropping systems in Eastern Africa.
Mergeai, Guy ULg; Silim, S. N.; Baudoin, Jean-Pierre ULg

in Status and potential of pigeonpea in eastern and southern Africa.Proceedings of a regional workshop, Nairobi, Kenya, 12-15 September 2000 (2001)

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See detailImproved mapping of Jupiter’s auroral features to magnetospheric sources
Vogt, Marissa. F.; Kivelson, Margaret. G.; Khurana, Krishan. K. et al

in Journal of Geophysical Research. Space Physics (2011), 116

The magnetospheric mapping of Jupiter's polar auroral emissions is highly uncertain because global Jovian field models are known to be inaccurate beyond ∼30 RJ. Furthermore, the boundary between open and ... [more ▼]

The magnetospheric mapping of Jupiter's polar auroral emissions is highly uncertain because global Jovian field models are known to be inaccurate beyond ∼30 RJ. Furthermore, the boundary between open and closed flux in the ionosphere is not well defined because, unlike the Earth, the main auroral oval emissions at Jupiter are likely associated with the breakdown of plasma corotation and not the open/closed flux boundary in the polar cap. We have mapped contours of constant radial distance from the magnetic equator to the ionosphere in order to understand how auroral features relate to magnetospheric sources. Instead of following model field lines, we map equatorial regions to the ionosphere by requiring that the magnetic flux in some specified region at the equator equals the magnetic flux in the area to which it maps in the ionosphere. Equating the fluxes in this way allows us to link a given position in the magnetosphere to a position in the ionosphere. We find that the polar auroral active region maps to field lines beyond the dayside magnetopause that can be interpreted as Jupiter's polar cusp; the swirl region maps to lobe field lines on the night side and can be interpreted as Jupiter's polar cap; the dark region spans both open and closed field lines and must be explained by multiple processes. Additionally, we conclude that the flux through most of the area inside the main oval matches the magnetic flux contained in the magnetotail lobes and is probably open to the solar wind. [less ▲]

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See detailAn Improved Method of Photometric Mode Identification: Applications to Slowly Pulsating B, beta Cephei, delta Scuti and gamma Doradus Stars
Dupret, Marc-Antoine ULg; Scuflaire, Richard ULg; Noels-Grötsch, Arlette ULg et al

in Astrophysics & Space Science (2003), 284

We present an improved version of the method of photometric mode identification based upon the inclusion of non-adiabatic eigenfunctions determined in the stellar atmosphere, according to the formalism ... [more ▼]

We present an improved version of the method of photometric mode identification based upon the inclusion of non-adiabatic eigenfunctions determined in the stellar atmosphere, according to the formalism recently proposed by Dupret et al. (2002). We apply our method to beta Cephei, Slowly Pulsating B, delta Scuti and gamma Doradus stars. Besides identifying the degree l of the pulsating stars, our method is also a tool for improving the knowledge of stellar interiors and atmospheres, by imposing constraints on the metallicity for beta Cephei and SPBs, the characteristics of the superficial convection zone for delta Scuti and gamma Doradus stars and the limb-darkening law. [less ▲]

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See detailAn Improved Methodology for Filling Missing Values in Spatiotemporal Climate Dataset: Application to Tanganyika Lake Dataset
Sorjamaa, Antti; Lendasse, Amaury; Cornet, Yves ULg et al

in Computational Geosciences (2010), 14(1), 55-64

In this paper, an improved methodology for the determination of missing values in a spatio-temporal database is presented. This methodology performs denoising projection in order to accurately fill the ... [more ▼]

In this paper, an improved methodology for the determination of missing values in a spatio-temporal database is presented. This methodology performs denoising projection in order to accurately fill the missing values in the database. The improved methodology is called EOF Pruning and it is based on an original linear projection method called Empirical Orthogo- nal Functions (EOF). The experiments demonstrate the performance of the improved methodology and present a comparison with the original EOF and with a widely-used Optimal Interpolation method called Objective Analysis. [less ▲]

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See detailImproved modelling of helium and tritium production for spallation targets
Leray, S.; Boudard, A.; Cugnon, Joseph ULg et al

in Nuclear Instruments & Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms (2010), 268(6), 581-586

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See detailImproved molecular diagnostics of idiopathic short stature and allied disorders: quantitative polymerase chain reaction-based copy number profiling of SHOX and pseudoautosomal region 1.
D'haene, Barbara; Hellemans, Jan; Craen, Margarita et al

in Journal of Clinical Endocrinology and Metabolism (2010), 95(6), 3010-8

CONTEXT: Short stature has an incidence of three in 100 in children. Reliable molecular genetic testing may be crucial in the context of beneficial disease management. Deletions spanning or surrounding ... [more ▼]

CONTEXT: Short stature has an incidence of three in 100 in children. Reliable molecular genetic testing may be crucial in the context of beneficial disease management. Deletions spanning or surrounding the SHOX gene account for a significant proportion of patients with idiopathic short stature (ISS) and allied disorders, such as Leri-Weill dyschondrosteosis. OBJECTIVE: Several shortcomings of current strategies for copy number profiling of the SHOX region prompted us to develop an improved test for molecular diagnostics of the SHOX region. DESIGN AND RESULTS: We introduced a quantitative PCR (qPCR)-based copy number profiling test, consisting of 11 amplicons targeting clinically relevant regions, i.e. the SHOX gene and regulatory regions. To ensure an optimal sensitivity and specificity, this test was validated in 32 controls and 18 probands with previously identified copy number changes. In addition, 152 probands with SHOX-associated phenotypes were screened, revealing 10 novel copy number changes. CONCLUSION: This highly validated qPCR test supersedes other approaches for copy number screening of the SHOX region in terms of reliability, accuracy, and cost efficiency. In addition, another strong point is the fact that it can be easily implemented in any standard equipped molecular laboratory. Our qPCR-based test is highly recommended for molecular diagnostics of idiopathic short stature and allied disorders. [less ▲]

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See detailImproved one-dimensional numerical simulation of transient mixed flow in water pipes network
Kerger, François ULg; Archambeau, Pierre ULg; Erpicum, Sébastien ULg et al

in Proceedings of the 2nd ENVITAM PhD Day (2008, January 29)

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See detailAN IMPROVED ONE-POINT INTEGRATION METHOD FOR LARGE-STRAIN ELASTOPLASTIC ANALYSIS
Stainier, Laurent ULg; Ponthot, Jean-Philippe ULg

in Computer Methods in Applied Mechanics & Engineering (1994), 118(1-2), 163-177

In this paper, we present a new one-point integration method generalizing Flanagan and Belytschko's method (Internat. J. Numer. Methods Engrg. 17 (1981) 679-706) and a modification of Belytschko and ... [more ▼]

In this paper, we present a new one-point integration method generalizing Flanagan and Belytschko's method (Internat. J. Numer. Methods Engrg. 17 (1981) 679-706) and a modification of Belytschko and Bindeman's method (Comput. Methods Appl. Mech. Engrg. 88 (1991) 311-340), both in the frame of large deformation elastoplastic analysis. These stabilization methods are combined with the radial return method used to integrate the constitutive law. Plane strain problems are first considered, and the method is then generalized to axisymmetrical situations. The explicit time integration scheme with its critical timestep is also considered. A few examples are presented that show the great time savings that can be obtained with reduced integration without any loss of accuracy, and even with a gain in the solution quality, since the underintegrated elements prove to be 'flexurally superconvergent'. [less ▲]

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