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See detailComparison of two drainage flow situations on a gentle forested slope
Heinesch, Bernard ULg; Yernaux, Michel ULg; Aubinet, Marc ULg

Poster (2010)

Drainage flows generated on a gentle slope in stable conditions were analysed at the forested site of Vielsalm (Belgium). Two distinct situations were encountered, one corresponding to vertical ... [more ▼]

Drainage flows generated on a gentle slope in stable conditions were analysed at the forested site of Vielsalm (Belgium). Two distinct situations were encountered, one corresponding to vertical convergence, characterised by a negative vertical velocity at the canopy top, the other corresponding to an equilibrium situation without any vertical movement. The causes of these two distinct flow patterns were analysed. Moreover, combined measurements of vertical velocity above the canopy and horizontal velocity divergence below the canopy were found to comply with the continuity equation: an acceleration of the horizontal flow was indeed observed in the trunk-space in convergence situations while not in equilibrium conditions. These measurements combined with those of the horizontal [CO2] gradient below the canopy were found to met the dilution hypothesis suggested by Aubinet et al.(2003): the horizontal [CO2] gradient was negative in convergence situations while slightly positive in equilibrium conditions. The existence of such patterns allows us to confirm the coherence of advection observations made at the site and help to better understand the mechanisms responsible of night flux exchanges at work in stable conditions in complex terrains. Nevertheless, difficulties were met when trying to obtain reliable estimates of the advection transport terms. The estimation of the vertical velocity in the trunk-space obtained by using the divergence measurements refuted the hypothesis of linearity of the vertical profile of vertical velocity, assumption usually used when computing vertical advection. This problem resulted in a great uncertainty on vertical advection which did not allowed to improve the night-flux estimation by adding advection terms to the turbulent flux and the storage. [less ▲]

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See detailComparison of two immunoassays for oxidized LDL determination
Le Goff, Caroline ULg; Haleng, Jeanine ULg; Denooz, André ULg et al

in Annales de Biologie Clinique (2009), 67(1),

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See detailComparison of two immunoassays for quantitative measurement of oxydized-LDL
Le Goff, Caroline ULg; Haleng, Jeanine ULg; Chapelle, Jean-Paul ULg

in Immuno-Analyse & Biologie Spécialisée [=IBS] (2009), 24

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See detailComparison of two inverse analysis techniques for learning deep excavation response
Hashash, Youssef; Levasseur, Séverine ULg; Osouli, Abdolreza et al

in Computers & Geotechnics (2010), 37

Performance observation is a necessary part of the design and construction process in geotechnical engineering. For deep urban excavations, empirical and numerical methods are used to predict potential ... [more ▼]

Performance observation is a necessary part of the design and construction process in geotechnical engineering. For deep urban excavations, empirical and numerical methods are used to predict potential deformations and their impacts on surrounding structures. Two inverse analysis approaches are described and compared for an excavation project in downtown Chicago. The first approach is a parameter optimization approach based on genetic algorithm (GA). GA is a stochastic global search technique for optimizing an objective function with linear or non-linear constraints. The second approach, self-learning simulations (SelfSim), is an inverse analysis technique that combines finite element method, continuously evolving material models, and field measurements. The optimization based on genetic algorithm approach identifies material properties of an existing soil model, and SelfSim approach extracts the underlying soil behavior unconstrained by a specific assumption on soil constitutive behavior. The two inverse analysis approaches capture well lateral wall deflections and maximum surface settlements. The GA optimization approach tends to overpredict surface settlements at some distance from the excavation as it is constrained by a specific form of the material constitutive model (i.e. hardening soil model); while the surface settlements computed using SelfSim approach match the observed ones due to its ability to learn small strain non-linearity of soil implied in the measured settlements. [less ▲]

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See detailComparison of two methods currently used to determine the interaction between cyclodextrins and drugs: phase solubility diagrams and NMR spectroscopy
Piel, Géraldine ULg; Moutard, Stephane; Perly, Bruno et al

in Journal of Drug Delivery Science and Technology (2004), 14(1, JAN-FEB), 87-91

Two methods usually used in the literature to determine stability constant values (Kc) of cyclodextrin complexes were compared: the phase solubility diagram and NMR spectroscopy. Two model drugs were used ... [more ▼]

Two methods usually used in the literature to determine stability constant values (Kc) of cyclodextrin complexes were compared: the phase solubility diagram and NMR spectroscopy. Two model drugs were used to determine limitations of both techniques: betamethasone and miconazole, with three cyclodextrins: beta-cyclodextrine (betaCD), dimethylated-betaCD (Dimeb) and trimethylated-betaCD (Trimeb). This study shows that both techniques can give the same Kc value if they are used in exactly the same conditions with well defined cyclodextrins. As a matter of fact, if the degree of substitution of cyclodextrin is not well defined (as it is often the case with Dimeb), results are biased. This study also shows that when interactions between both molecules are weak (< 1000 M-1), stability constants can not be determined by NMR due to low chemical shift variations. The limitations of the phase solubility diagram method are an oversimplification of the solubility data which can lead to large errors in the calculation of the stability constant values. Moreover, this method is time and material consuming. [less ▲]

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See detailA comparison of two methods for pulmonary function testing in horses with upper and lower airway obstruction
Van Erck, Emmanuelle; Duvivier, D. H.; Art, Tatiana ULg et al

Poster (1997, October 24)

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See detailComparison of Two Methods, UHPLC-UV and UHPLC-MS/MS, for the Quantification of Polyphenols in Cider Apple Juices
Verdu, Cindy ULg; Gatto, Julia; Freuze, Ingrid et al

in Molecules (2013), 18/9

Abstract: The aim of this study was to develop faster and more efficient phenotyping methods for in-depth genetic studies on cider apple progeny. The UHPLC chromatographic system was chosen to separate ... [more ▼]

Abstract: The aim of this study was to develop faster and more efficient phenotyping methods for in-depth genetic studies on cider apple progeny. The UHPLC chromatographic system was chosen to separate polyphenolic compounds, and quantifications were then simultaneously performed with a UV-PDA detector and an ESI-triple quadrupole mass analyzer (SRM mode). Both quantification methods were validated for 15 major compounds using two apple juice samples, on the basis of linearity, limits of detection and quantification, recovery and precision tests. The comparison between UV and SRM quantifications in 120 different samples of a cider apple progeny showed an excellent correlation for major compounds quantified with both methods. However, an overestimation was revealed for five compounds with the UV detector and the mass analyzer. Co-elution and matrix effects are discussed to explain this phenomenon. SRM methods should therefore be considered with restrictions in some cases for quantification measurements when several phenolic compounds are simultaneously quantified in complex matrices such as apple juices. For both methods, analyses were carried out over short periods of time while maintaining a high quality for the simultaneous quantification of phenolic compounds in apple juice. Each method is relevant for more in-depth genetic studies of the polyphenol content of apple juice. [less ▲]

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See detailA Comparison of Two Spelling Brain-Computer Interfaces Based on Visual P3 and SSVEP in Locked-In Syndrome
Combaz, Adrien; Chatelle, Camille ULg; Robben, Arne et al

in PLoS ONE (2013), 8(9), 73691

Objectives: We study the applicability of a visual P3-based and a Steady State Visually Evoked Potentials (SSVEP)-based Brain-Computer Interfaces (BCIs) for mental text spelling on a cohort of patients ... [more ▼]

Objectives: We study the applicability of a visual P3-based and a Steady State Visually Evoked Potentials (SSVEP)-based Brain-Computer Interfaces (BCIs) for mental text spelling on a cohort of patients with incomplete Locked-In Syndrome (LIS). Methods: Seven patients performed repeated sessions with each BCI. We assessed BCI performance, mental workload and overall satisfaction for both systems. We also investigated the effect of the quality of life and level of motor impairment on the performance. Results: All seven patients were able to achieve an accuracy of 70% or more with the SSVEP-based BCI, compared to 3 patients with the P3-based BCI, showing a better performance with the SSVEP BCI than with the P3 BCI in the studied cohort. Moreover, the better performance of the SSVEP-based BCI was accompanied by a lower mental workload and a higher overall satisfaction. No relationship was found between BCI performance and level of motor impairment or quality of life. Conclusion:Our results show a better usability of the SSVEP-based BCI than the P3-based one for the sessions performed by the tested population of locked-in patients with respect to all the criteria considered. The study shows the advantage of developing alternative BCIs with respect to the traditional matrix-based P3 speller using different designs and signal modalities such as SSVEPs to build a faster, more accurate, less mentally demanding and more satisfying BCI by testing both types of BCIs on a convenience sample of LIS patients. [less ▲]

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See detailComparison of Ultra capacitors and Batteries Technologies to Optimize Hybrid Electric Vehicle Efficiency
Nzisabira, Jonathan; Louvigny, Yannick ULg; Duysinx, Pierre ULg

in Proceedinbg of 3rd European Symposium on Supercapacitors and Application (ESSCAP08) (2008, November)

The acceptance of Electric and Hybrid Electric Vehicle is related to their eco-efficiency, i.e. their ability to both reduce environmental impact while also providing a sufficient user satisfaction. The ... [more ▼]

The acceptance of Electric and Hybrid Electric Vehicle is related to their eco-efficiency, i.e. their ability to both reduce environmental impact while also providing a sufficient user satisfaction. The objective of this study is to provide a rationale design tool based on a multidisciplinary optimization approach to support the design of hybrid electric powertrain to simultaneously maximize user satisfaction complex criteria and minimize the Eco-score. In order to carry out the optimization problem efficiently the approach makes use of metamodeling techniques in order to save computation time in the optimization process that is driven by a Genetic Algorithm. The approach is applied to highlight the effect of different energy storage systems (batteries v.s. ultra capacitors) upon the optimized HEV design taking care of both Eco-score and User satisfaction. In the selected application that is a heavy urban bus with a mild hydrid electric powertrain, the ultra capacitors are slightly superior to NiMH batteries when emphasizing the Ecoscore criterion. [less ▲]

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See detailComparison of Ultra Capacitors, Hydraulic Accumulators and Batteries Technologies to Optimize Hybrid Vehicle Ecoefficiency
Nzisabira, Jonathan; Louvigny, Yannick ULg; Duysinx, Pierre ULg

in Proceeding of 2nd IEEE Int. Conference of Power Engineering, Energy, and Electric Drives (2009, March)

The main objective of vehicle powertrain hybridization is to improve the fuel consumption and environment pollutants impact (Eco-score) without decreasing the vehicle performances and other user ... [more ▼]

The main objective of vehicle powertrain hybridization is to improve the fuel consumption and environment pollutants impact (Eco-score) without decreasing the vehicle performances and other user satisfaction criteria. The Eco efficiency is a global index which accounts for both environmental impacts and user satisfaction. The Hybrid vehicles ability to overcome these two requirements depends on the optimal choice of their key mechanical, electric or hydraulic components. Some energy storage systems like ultra capacitors and hydraulic system are environmentally friendly and meet some user satisfaction criteria like daily cost, security, short charge/discharge duration and long life service. On the contrary, others like batteries have some times a environmental impact mitigate. The objective of this study is to establish a comparison between HEV (hybrid electric vehicle) and HHV(hybrid hydraulic vehicle) configuration by highlighting the effect of different energy storage systems (batteries, ultra capacitors, hydraulic system), mechanical and electric components sizes (engine, motors) upon the optimized HEV design taking care of both Eco-score and User satisfaction for different driving scenarios. The approach is formulated as a multidisciplinary optimization problem. At first, the HEV and HHV are modeled and simulated using ADVISOR (advanced vehicle simulator) with respect to several driving situations. Then emissions can be determined and the Ecoscore indicator can be calculated. User Satisfaction can be evaluated based on performance criteria extracted from ADVISOR simulation and on simple evaluation tools relying on the state-of-the art of technological information for safety, reliability and daily cost. The design problem is stated as follows: select mechanical, electric or hydraulic components (e.g. engine, motor and energy storage system sizes) to minimize the Ecoscore indicator and to maximize user satisfaction criteria subject to catalogue constraints on the choice of the components. The approach is illustrated on applications dealing with mild parallel hybrid buses. Results show that the hybrid electric buses using ultra capacitors have almost the same performances as those using batteries. However, the preferred choice would go towards super capacities because they have other appreciable properties compared to the batteries: the very high lifetime, high efficiency of charge and discharge and no polluting recyclability. Despite a smaller fuel saving than a HEV, the HHV technology has a chance to compete with HEV because of the hydraulic components low cost (industrial maturity), no pollutants recyclability due to the possible using of water as motor/pump fluid. HHV technology is a possible alternative in niche markets such as urban buses; bin-lorries or heavy urban delivery vehicles. [less ▲]

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See detailComparison of ultrasonography and MRI in the evaluation of palmar foot pain
Van Thielen, B.; Murray, R.; De Ridder, F. et al

in ESVOT Proceedings (2008)

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See detailComparison of ultrasonography, bovine pregnancy specific B, and bovine pregnancy-associated glycoprotein 1 test for pregnancy detection in dairy cows
Szenci, Otto; Beckers, Jean-François ULg; Humblot, Patrice et al

in Theriogenology (1998), 50(1), 77-88

At Days 26 to 58 after AI, 138 Holstein-Friesian dairy cows were repeatedly examined by ultrasonography, using a 7.5 MHz linear-array rectal transducer. The total calving rate was 37.6% (52/138), and late ... [more ▼]

At Days 26 to 58 after AI, 138 Holstein-Friesian dairy cows were repeatedly examined by ultrasonography, using a 7.5 MHz linear-array rectal transducer. The total calving rate was 37.6% (52/138), and late embryonic mortality occurred 8.6% of the cows (12/138). On the days of ultrasound scanning, blood samples were drawn from the jugular vein for measuring the concentration of bovine pregnancy-specific protein B (bPSPB) and bovine pregnancy-associated glycoprotein 1 (bPAG 1). When compared with calving results, there were no significant differences in accurate diagnosis of pregnant cows were found between the 3 methods. However, when recognition of an embryo proper with a beating heart was used as the criterion for positive ultrasonographic diagnosis significantly fewer (P<0.001) pregnant cows were correctly identified than by the other 2 tests. When compared with the noncalving cows, significantly fewer (P<0.001) false positive diagnoses were made by the 2 ultrasonographic tests than by the PSPB and bPAG 1 tests, while significantly fewer (P<0.001) false positive diagnoses were made by the bPSPB test than by the bPAG 1 test. The accuracy of detecting nonpregnant animals by both protein tests was limited by the relatively long half-life of these proteins after calving and by early embryonic mortality. [less ▲]

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See detailComparison of ultrasound and pregnancy associated glycoproteins to diagnose and follow ongoing or failing pregnancy in pregnant heifers on the market
Prvanović, N; Beckers, Jean-François ULg; Sulon, J et al

in Slovenian veterinary research (2006), 43(10), 41-43

The objective of the present study was to compare transrectal ultrasonography and pregnancy associated glycoprotein (PAG) tests for determination of pregnancy in 72 Holstein-Friesian heifers imported from ... [more ▼]

The objective of the present study was to compare transrectal ultrasonography and pregnancy associated glycoprotein (PAG) tests for determination of pregnancy in 72 Holstein-Friesian heifers imported from Holland to Croatia. All heifers came to Croatia with written confirmation of pregnancy. During caranteen we preformed rectal and ultrasound exploration of heifers and simultaneously collected blood samples from each heifer. PAG concentrations were determined by a RIA immunoassay using bovine PAG 67 KDa as a tracer and standard. In our study 68 heifers were confirmed to be pregnant by both methods and 4 cows were confirmed for abortion by PAG test and nonpregnant according to ultrasound checking. Transrectal ultrasonography is accurate test for pregnancy diagnosis in pregnant heifers but it is impossible to say only on basis of ultrasound examination if heifers conceived and aborted or they failed to conceive in the first place. PAG RIA test is not only highly accurate and reliable method to distinguish between pregnant and nonpregnant heifers on the market. It is also useful to determine whether heifers were pregnant and embryo died and was absorbed during the transfer or heifers failed to conceive. It is possible because level of PAG persists in circulation after abortion or embrional death. In doubtful cases it can be used as a proof of pregnancy existence in heifers later confirmed to be nonpregnant. [less ▲]

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See detailA Comparison of Unawareness in Frontotemporal Dementia and Alzheimer's Disease
Salmon, Eric ULg; Perani, Daniela; Collette, Fabienne ULg et al

in Journal of Neurology, Neurosurgery & Psychiatry (2008), 79(2), 176-9

BACKGROUND: Loss of insight is a core diagnostic feature of frontotemporal dementia (FTD) and anosognosia is frequently reported in Alzheimer's disease (AD). AIM: To compare unawareness (anosognosia) for ... [more ▼]

BACKGROUND: Loss of insight is a core diagnostic feature of frontotemporal dementia (FTD) and anosognosia is frequently reported in Alzheimer's disease (AD). AIM: To compare unawareness (anosognosia) for different symptoms, measured with a discrepancy score between patient's and caregiver's assessment, in AD and FTD. METHOD: In a prospective, multi-centre study, 123 patients with probable AD, selected according to the NINCDS-ADRDA procedure, were matched for age, sex, education, disease duration and dementia severity to patients with FTD (n = 41), selected according to international consensus criteria. A research complaint questionnaire was used to obtained patient's and caregiver's assessment concerning neuropsychological and behavioural symptoms. Data were compared in each group and between groups. Unawareness (measured by discrepancy scores) was compared between patients with AD and FTD. RESULTS: The caregivers generally assessed symptoms more severely than did patients, but both patient groups reported changes in affect (depressive mood or irritability) as their caregivers did. Unawareness was greater in patients with FTD than in patients with AD for language and executive difficulties, and for changes in behaviour and daily activities. CONCLUSION: The main finding is that unawareness was observed in both patients with FTD and patients with AD for most clinical domains. However, qualitative and quantitative differences showed that lack of awareness was greater in patients with FTD. [less ▲]

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See detailComparison of urinary odor-induced glomerular activation in the main olfactory bulb of aromatase knock-out and wild type female mice
Martel, K. L.; Keller, Matthieu ULg; Douhard, Quentin ULg et al

in Neuroscience Letters (2007), 421(2), 101-105

Previously [D.W. Wesson, M. Keller, Q. Douhard, M.J. Baum, J. Bakker, Enhanced urinary odor discrimination in female aromatase knockout mice, Horm. Behav. 49 (2006) 580-586] female aromatase knock out ... [more ▼]

Previously [D.W. Wesson, M. Keller, Q. Douhard, M.J. Baum, J. Bakker, Enhanced urinary odor discrimination in female aromatase knockout mice, Horm. Behav. 49 (2006) 580-586] female aromatase knock out mice successfully learned to discriminate in a food-motivated go/no-go task between urinary volatiles from ovariectomized female mice treated with estradiol as opposed to estradiol plus progesterone whereas wild type females failed to learn this odor discrimination. We asked whether this behavioral difference is reflected in the ability of these two types of urinary volatiles to differentially stimulate Fos expression in juxtaglomerular cells (an index of glomerular activation) of the main olfactory bulb (MOB) in wild type versus ArKO female mice. Statistically significant differences in the profiles of MOB glomerular activation were seen in ovariectomized, estrogen-treated ArKO as well as WT female subjects following exposure to urinary volatiles from ovariectomized females given estradiol alone as opposed to estradiol plus progesterone. Therefore, previously observed differences between females of the two genotypes in their behavioral responses to these odors must reflect differential processing in more central segments of the olfactory pathway instead of in the MOB. (c) 2007 Elsevier Ireland Ltd. All rights reserved. [less ▲]

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See detailComparison of vegetation distributions and terrestrial carbon budgets reconstructed for the last glacial maximum with several biosphere models
François, Louis ULg; Kaplan, J.; Otto, D. et al

in Braconnot, P. (Ed.) PMIP, 2000: Paleoclimate Modelling Intercomparison Project (PMIP), Proceedings of the Third PMIP workshop (2000)

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See detailComparison of ventrodorsal and dorsoventral radiographic projections for hip dysplasia diagnosis
Saunders, J.; Godefroid, T.; Snaps, Frédéric ULg et al

in Veterinary Record : Journal of the British Veterinary Association (1999), (145), 109-110

Detailed reference viewed: 13 (2 ULg)