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See detailPerformance of Solmacs, a High PV Solar Concentrator With Efficient Optics
Thibert, Tanguy ULg; Hellin, Marie-Laure ULg; Loicq, Jerôme ULg et al

in AIP Conference Proceedings, , Volume 1477 (2012, October 05)

A new solar panel with high concentration photovoltaic technology (x700) has been designed, prototyped and tested in the SOLMACS project. The quality of concentrating optics is a key factor for high ... [more ▼]

A new solar panel with high concentration photovoltaic technology (x700) has been designed, prototyped and tested in the SOLMACS project. The quality of concentrating optics is a key factor for high module efficiency. Therefore new dedicated PMMA Fresnel lenses were studied and produced by injection molding. Lens design, material and production process were optimized to achieve a high optical yield of 86%. Thorough lens performance assessment in optical laboratory was completed with lifetime UV aging tests. Another important aspect is the thermal control of the hot spot created under the solar cell that receives the concentrated flux of 700 Suns. A dedicated heat spreader was developed to achieve passive thermal control with minimum mass and cost. This was supported by thermal models and tests at both cell and module level. 35% triple junction cells were implemented in the module. Micro-assembly technologies were used for the cell packaging and electrical connections. In support to the research, a continuous solar simulator was designed and built to assess the system performance, both at component and module level. The concentrator developments were integrated in a prototype and tested both indoor with the simulator and outdoor on the CSL solar test platform. The overall efficiency of the PV concentrator module is 28.5%. [less ▲]

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See detailPerformance of the IDS-iSYS 1,25-dihydroxy vitamin D assay
GADISSEUR, Romy ULg; LUKAS, Pierre ULg; CARLISI, Ignazia ULg et al

Poster (2013, July)

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See detailPerformance of the VERSANT (R) HIV-1 Resistance Assays (LiPA) for detecting drug resistance in therapy-naive patients infected with different HIV-1 subtypes
Derdelinckx, Inge; Van Laethem, Kristel; Maes, Baert et al

in FEMS Immunology & Medical Microbiology (2003), 39(2), 119-124

In this study we evaluated the performance of the VERSANT((R)) HIV-1 Resistance Assays (LiPA) in detecting drug resistance in therapy-naive HIV-infected patients diagnosed in Belgium in 2000. We compared ... [more ▼]

In this study we evaluated the performance of the VERSANT((R)) HIV-1 Resistance Assays (LiPA) in detecting drug resistance in therapy-naive HIV-infected patients diagnosed in Belgium in 2000. We compared the results with population sequencing and found concordance to be in line with previous studies in treatment-experienced patients (86.87% for reverse transcriptase (RT); 92.77% for protease (PRO)). Discordance was mainly due to indeterminate reactions on LiPA (8.45% for RT; 6.85% for PRO) and minor discordances (4.13% for RT; 0.25% for PRO). Major discordances were rare (0.46% for RT; 0.12% for PRO). Indeterminate reactions were significantly associated with strains belonging to non-B subtypes. (C) 2003 Federation of European Microbiological Societies. Published by Elsevier B.V.. All rights reserved. [less ▲]

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See detailPerformance of three HIV-1 DNA real-time PCRs for early diagnosis in infants and adults
Iserentant, G.; Masquelier, C.; Lambert, C. et al

Poster (2011, March)

Background Early pediatric HIV-1 diagnosis is a challenge in resource limited countries to identify HIV-infected newborns to provide early ART treatment. HIV DNA PCR testing is an accurate method for ... [more ▼]

Background Early pediatric HIV-1 diagnosis is a challenge in resource limited countries to identify HIV-infected newborns to provide early ART treatment. HIV DNA PCR testing is an accurate method for diagnosis in newborns and could be valuable for monitoring HIV infection in adults. We have evaluated the analytical, clinical performances and genotype inclusivity of 3 real-time Taqman PCRs targeting the ltr, int and env genes. Material and methods Total DNA was extracted from whole blood and Dried Blood Spots (DBS) using the NucleoSpin Blood kit (Macherey Nagel) and the Chelex resin. DNA amplification was performed using the Qiagen Multiplex PCR kit and detected on a 7300 Real time PCR system (Applied Biosystems). Method validation was realized as required by ISO 15189 standard. The accuracy profile methodology was applied. HIV-1 DNA of ACH2 cells (0, 25, 50, 100, 1000 and 5000 copies/PCR) mixed in whole blood were measured in 4 different series (2 PCR kits and 2 operators) of 5 independent DNA extraction of each standard. Linear and quadratic weighted and non weighted regression models were tested. Trueness, precision, limit of quantifications of the method and accuracy of the results were obtained for each model and compared. 93 whole blood samples of ART treated-patients with undetectable or low viraemia of 16 B and 77 non-B subtypes were assessed. Clinical evaluation of the assay was performed on 26 whole blood samples and 238 DBS from infants of Guinea Conakry determined HIV+ using the rapid Bioline HIV test Results The calibration model providing the most accurate results was the linear regression with an r² equal to 0.92 for ltr, 0.88 for int and 0.95 for env. Trueness, precision and accuracy were highly acceptable for the 3 sets of primers/probe not exceeding -0.23 log(copies/PCR) for bias and 0.5 log(copies) for intermediate precision standard deviation, respectively. The estimated lower limit of quantification was 41, 475 and 25 copies/PCR for ltr, int and env respectively. The accuracy profile of each gene showed that each future measurement using this assay has 80% probability to be within a limit of 0.5 log (copies/PCR) around the reference or true value of copies of each gene. 52/93 whole blood samples of ART-treated patients had 3 positive genes (Ct<40 cycles), 38/93 had two positive genes and 4/93 had only one positive gene (ltr). Among these patients, 3 were assigned as long term progressors and one was a subtype C strain. Clinical evaluation of the assay identified 1 HIV-1 infected newborn and 3 adults (at least 2 positive genes) for which HIV-1 infection was confirmed either by serology or viral load techniques as well as 96 HIV-1 infected infants using DBS. Conclusions This assay is suitable for detection of proviral HIV-1 DNA in infants and adults on whole blood and DBS samples. Despite an estimated lower limit of quantification higher than ltr and env, the int PCR was required to achieve a good genotype inclusivity. The method was fully validated as required by ISO 15189 and showed to provide sufficiently reliable results. [less ▲]

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See detailPerformance of vapor compression systems with compressor oil flooding and regeneration
Bell, Ian ULg; Groll, Eckhard; Braun, James

in International Journal of Refrigeration (2011), 34(1), 225233

Vapor compression refrigeration technology has seen great improvement over the last several decades in terms of cycle efficiency through a concerted effort of manufacturers, regulators, and research ... [more ▼]

Vapor compression refrigeration technology has seen great improvement over the last several decades in terms of cycle efficiency through a concerted effort of manufacturers, regulators, and research engineers. As the standard vapor compression systems approach practical limits, cycle modifications should be investigated to increase system efficiency and capacity. One possible means of increasing cycle efficiency is to flood the compressor with a large quantity of oil to achieve a quasi-isothermal compression process, in addition to using a regenerator to increase refrigerant subcooling. In theory, compressor flooding and regeneration can provide a significant increase in system efficiency over the standard vapor compression system. The effectiveness of compressor flooding and regeneration increases as the temperature lift of the system increases. Therefore, this technology is particularly well suited towards lower evaporating temperatures and high ambient temperatures as seen in supermarket refrigeration applications. While predicted increases in cycle efficiency are over 40% for supermarket refrigeration applications, this technology is still very beneficial for typical air-conditioning applications, for which improvements in cycle efficiency greater than 5% are predicted. It has to be noted though that the beneficial effects of compressor flooding can only be realized if a regenerator is used to exchange heat between the refrigerant vapor exiting the evaporator and the liquid exiting the condenser. [less ▲]

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See detailPerformance on a computerized shopping task significantly predicts real world functioning in persons diagnosed with bipolar disorder.
Laloyaux, Julien ULg; Pellegrini, Nadia; Mourad, Haitham et al

in Psychiatry Research (2013), 210(2), 465-471

Persons diagnosed with bipolar disorder often suffer from cognitive impairments. However, little is known concerning how these cognitive deficits impact their real world functioning. We developed a ... [more ▼]

Persons diagnosed with bipolar disorder often suffer from cognitive impairments. However, little is known concerning how these cognitive deficits impact their real world functioning. We developed a computerized real-life activity task, where participants are required to shop for a list of grocery store items. Twenty one individuals diagnosed with bipolar disorder and 21 matched healthy controls were administered the computerized shopping task. Moreover, the patient group was assessed with a battery of cognitive tests and clinical scales. Performance on the shopping task significantly differentiated patients and healthy controls for two variables: Total time to complete the shopping task and Mean time spent to consult the shopping list. Moreover, in the patient group, performance on these variables from the shopping task correlated significantly with cognitive functioning (i.e. processing speed, verbal episodic memory, planning, cognitive flexibility, and inhibition) and with clinical variables including duration of illness and real world functioning. Finally, variables from the shopping task were found to significantly explain 41% of real world functioning of patients diagnosed with bipolar disorder. These findings suggest that the shopping task provides a good indication of real world functioning and cognitive functioning of persons diagnosed with bipolar disorder. [less ▲]

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See detailPerformance on an everyday life activity in persons diagnosed with alcohol dependency compared to healthy controls: Relations between a computerized shopping task and cognitive and clinical variables.
Laloyaux, Julien ULg; Michel, Céline; Mourad, Haitham et al

in Alcohol & Alcoholism (2012), 47(3), 240-247

Aim: Persons diagnosed with alcohol dependency often suffer from cognitive impairments. Little is known, however, concerning how these cognitive deficits impact complex, everyday life activities. By this ... [more ▼]

Aim: Persons diagnosed with alcohol dependency often suffer from cognitive impairments. Little is known, however, concerning how these cognitive deficits impact complex, everyday life activities. By this experiment, we wished to contribute to a better characterization of the nature of everyday life difficulties in patients with alcohol dependency using a computerized shopping task. Methods: We developed a computerized real-life activity task (shopping task), where participants are required to shop for a list of 8 grocery store items. Twenty individuals diagnosed with alcohol dependency and 20 healthy controls were administered a battery of cognitive tests, clinical scales and the computerized shopping task. Results: Performance on the computerized shopping task significantly differentiated patients and healthy controls for several variables and in particular for Total time. Moreover, Total time to complete the task correlated significantly with several cognitive measures. In particular, poor performance on measures of processing speed, verbal episodic memory, cognitive flexibility and inhibition were significantly correlated with longer Total time. Finally, longer Total time was significantly correlated with poorer everyday life functioning and longer duration of illness. Conclusions: These findings suggest that the computerized task used in the present study is a good proxy measure of the level of everyday life and cognitive functioning of persons diagnosed with alcohol dependency. [less ▲]

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See detailPerformance relative des règles linéaire, quadratique et logistique en analyse discriminante
Glele Kakaï, R.; Palm, Rodolphe ULg

in XXXVIèmes Journées de Statistique (2004, May)

Monte Carlo study is achieved to compare linear, quadratic and logistic classification rules for two groups, in 480 situations related to the type of distribution, the overlap of the populations, the ... [more ▼]

Monte Carlo study is achieved to compare linear, quadratic and logistic classification rules for two groups, in 480 situations related to the type of distribution, the overlap of the populations, the number of variables, the sample size and the heteroscedasticity degree of the model, which is measured by a parameter gamma defined in the study. The results of this study show that the quadratic rule is the best only for severe heteroscedastic normal or moderate non-normal models with high overlap. The linear rule is the best for homoscedastic normal or moderate non-normal models with low overlap. The logistic rule is the best for severe non-normal models except when homoscedasticity occurs. In the order situations linear and logistic rules have almost the same performance. By considering the parameters computed on the data samples, the linear rule gives the best performance for high values of r whereas logistic rule performs is best for low or moderate values of the same parameter. [less ▲]

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See detailLa performance sociétale
Crutzen, Nathalie ULg

Article for general public (2010)

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See detailPerformance Study of an Overlay Approach to Active Routing in Ad Hoc Networks
Calomme, Sandrine; Leduc, Guy ULg

(2004, June)

We motivate the use of the active technology for routing in ad hoc networks. We present an active architecture where passive and active nodes can operate together, avoiding any change in the legacy muti ... [more ▼]

We motivate the use of the active technology for routing in ad hoc networks. We present an active architecture where passive and active nodes can operate together, avoiding any change in the legacy muti-hop routing protocol they use. We detail a basic reactive protocol which can be used to build any overlay on top of an ad hoc network. We model it as an active application called Re-Active Routing (RAR). RAR provides dynamic routing in dense and sparse active overlays. We investigate its performance in static and dynamic environments and show that it depends substantially on the active range, i.e. on the allowed maximal number of hops between two active nodes. For a well-chosen active range, RAR achieves good performance even if the mobility level is high and the overlay density is as low as 12.5 %. [less ▲]

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See detailPerformance study of ground-based infrared Bracewell interferometers. Application to the detection of exozodiacal dust disks with GENIE
Absil, Olivier ULg; den Hartog, R.; Gondoin, P. et al

in Astronomy and Astrophysics (2006), 448

Nulling interferometry, a powerful technique for high-resolution imaging of the close neighbourhood of bright astrophysical objets, is currently considered for future space missions such as Darwin or the ... [more ▼]

Nulling interferometry, a powerful technique for high-resolution imaging of the close neighbourhood of bright astrophysical objets, is currently considered for future space missions such as Darwin or the Terrestrial Planet Finder Interferometer (TPF-I), both aiming at Earth-like planet detection and characterization. Ground-based nulling interferometers are being studied for both technology demonstration and scientific preparation of the Darwin/TPF-I missions through a systematic survey of circumstellar dust disks around nearby stars. In this paper, we investigate the influence of atmospheric turbulence on the performance of ground-based nulling instruments, and deduce the major design guidelines for such instruments. End-to-end numerical simulations allow us to estimate the performance of the main subsystems and thereby the actual sensitivity of the nuller to faint exozodiacal disks. Particular attention is also given to the important question of stellar leakage calibration. This study is illustrated in the context of GENIE, the Ground-based European Nulling Interferometer Experiment, to be installed at the VLTI and working in the L' band. We estimate that this instrument will detect exozodiacal clouds as faint as about 50 times the Solar zodiacal cloud, thereby placing strong constraints on the acceptable targets for Darwin/TPF-I. [less ▲]

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See detailPerformance, slaughter characteristics and meat quality of young bulls from Belgian Blue, Limousin and Aberdeen Angus breeds fattened with a sugar-beet pulp or a cereal-based diet
Cuvelier, Christine ULg; Cabaraux, Jean-François ULg; Dufrasne, Isabelle ULg et al

in Animal Science (2006), 82(Part 1), 125-132

Thirty-six young fattening bulls from three breeds (Belgian Blue, Limousin and Aberdeen Angus) were fattened over 5 months with fattening diets based either on sugar-beet pulp or on cereals. Fattening ... [more ▼]

Thirty-six young fattening bulls from three breeds (Belgian Blue, Limousin and Aberdeen Angus) were fattened over 5 months with fattening diets based either on sugar-beet pulp or on cereals. Fattening performance as well as carcass and meat characteristics were measured. There were few relevant effects of the diets on the parameters. The breeds also showed similar fattening features. However, the BB had higher killing-out proportion and their carcasses presented better scores in terms of conformation and fattening. The meat quality of the breeds differed, especially in terms of luminosity, redness and cooking losses. There were also significant influences of breed on the chemical composition of meat; fat content was lowest in Belgian Blue and highest in Aberdeen Angus. Such specificities could help to allocate breeds in appropriate niches in Belgium. [less ▲]

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See detailPerformance-based Approaches for high strength Tubular columns and connections under Earthquake and fire Loadings (ATTEL) - D4
Sommariva, Manuel; Maio, Daniele; Demonceau, Jean-François ULg et al

Report (2012)

Fire test data

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See detailPerformances and limitations of the HRMS method for dioxins, furans and dioxin-like PCBs analysis in animal feedingstuffs Part I: Results of an inter-laboratory study
Eppe, Gauthier ULg; Cofino, W. P.; De Pauw, Edwin ULg

in Analytica Chimica Acta (2004), 519(2), 231-242

The European strategy for dioxin monitoring of the food chain has defined high-resolution gas chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS) method as the confirmatory method that ... [more ▼]

The European strategy for dioxin monitoring of the food chain has defined high-resolution gas chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS) method as the confirmatory method that can provide reliable and comparable results at sub-parts per trillion (ppt) level. This paper describes the first inter-laboratory study on dioxins, furans and dioxin-like PCBs by HRGC/HRMS method in animal feedingstuffs. Two different statistical approaches (ISO 5725 and Cofino's statistics) were used for the statistical evaluation. For this particular study, the performances of the HRGC/HRMS method seem to be congener-independent in repeatability and reproducibility conditions over a concentration range covering more than four orders of magnitude. Results clearly show the effect of precision loss below 0.1 ppt level per congener in repeatability conditions and below 0.2 ppt level per congener in reproducibility conditions. LODs reported by the laboratories give median values of 0.02 ng/kg for most of the toxic congeners. Relative standard deviation between the laboratories' mean values using upper-bound approach for TEQ calculation is 6.2%, more than twice the maximum level set at 0.75 ng TEQ/kg of product. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailPerformances and limitations of the HRMS method for dioxins, furans and dioxin-like PCBs analysis in animal feedingstuffs Part II: Does it comply with the European pro-active approach?
Eppe, Gauthier ULg; Maghuin-Rogister, Guy ULg; De Pauw, Edwin ULg

in Analytica Chimica Acta (2004), 519(2), 243-253

Based on the results obtained from the inter-laboratory study in Part 1, different approaches for detection and quantification limits are evaluated and discussed. An overview of the most commonly used ... [more ▼]

Based on the results obtained from the inter-laboratory study in Part 1, different approaches for detection and quantification limits are evaluated and discussed. An overview of the most commonly used concepts and terminologies in analytical chemistry is presented with the aim of establishing a link between them. Whatever the method used by laboratories for detection limit assessment, the median LOD value reported for the less chlorinated PCDD/Fs (i.e. 0.02 ng/kg) is in good agreement with the values recalculated using the inter-laboratory data. For LOQ the Eurachem approach based on a pre-established percentage of repeatability RSD appears to be. suitable. The study shows that a pre-established RSDr of 20% is recommended in order to achieve an acceptable LOQ of 0.05 ng/kg per congener. The 20% value seems to be sufficiently low to act tolerable RSD close to maximum limits. Furthermore, the repeatability and the reproducibility standard deviation against parts-per-trillion congener levels has been modeled by inverse first order functions. This congener precision model provides an interesting tool to subsequently assess the performances of the method in TEQ close to regulatory limits. Finally, the paper discusses two different ways of reporting and interpreting the results to assess compliance against statutory limits. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailPerformances de croissance et aptitudes bouchères du Poulet Kabyle
Moula, Nassim ULg; Antoine-Moussiaux, Nicolas ULg; Ait Kaki, Asma ULg et al

Poster (2012, May 27)

Face à la hausse rapide de la consommation mondiale de viande de volaille et afin de s’inscrire dans la perspective d’un développement durable, l’aviculture a connu et connaîtra encore de profondes ... [more ▼]

Face à la hausse rapide de la consommation mondiale de viande de volaille et afin de s’inscrire dans la perspective d’un développement durable, l’aviculture a connu et connaîtra encore de profondes mutations. L’expansion rapide de l’élevage intensif de souches hybrides, génétiquement uniformes, se réalise au détriment des races locales de poules. Ces dernières constituent pourtant un outil central du développement socio-économique rural dans diverses régions du monde. Le but de cette étude est d’étudier les performances de croissance du Poulet Kabyle en production intensive. L’expérimentation s’est déroulée dans la Région de Basse Kabylie et a consisté en deux essais consécutifs de mars à juin 2010 (n=150 poussins) et d’août à novembre 2010 (n=155 poussins). À l’éclosion, le poids moyen des poussins de la première répétition (mâles : 41,29 g, femelles : 36,26 g) n’était pas significativement différent (p>0,05) de celui de la deuxième répétition (mâles : 37,30 g, femelles : 31,94 g). A la fin de l’expérimentation, les poulets de la première répétition présentaient un poids significativement (p<0,05) supérieur à ceux de la deuxième répétition (mâles : 1978,93 g, femelles : 1448,57 g vs. mâles : 1803,30 g, femelles : 1234,48 g). L'étude des différents paramètres de la courbe de croissance (modèle de Gompertz) a révélé des valeurs différentes selon le sexe et la répétition. Aucune différence significative (p>0,05) n’a été observée entre les mortalités, les poids moyens à l’abattage, les rendements, les pH des muscles, des animaux des deux répétitions. Le poids moyen à l’abattage des mâles et leur rendement a été significativement (p<0,05) supérieur à celui des femelles. Les pH des muscles se stabilisent à une valeur appelée pH ultime variant de 5,68 à 5,81. [less ▲]

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See detailPerformances de production de la population de poules locales de la Wilaya de Bejaia
Ait Kaki, Asma ULg; Moula, Nassim ULg; Antoine-Moussiaux, Nicolas ULg et al

Poster (2013, November 30)

Cette étude a pour objectif d’évaluer le potentiel productif de la population de poules locales de la Wilaya de Bejaia, en caractérisant d’une part les performances de croissance, et d’autre part les ... [more ▼]

Cette étude a pour objectif d’évaluer le potentiel productif de la population de poules locales de la Wilaya de Bejaia, en caractérisant d’une part les performances de croissance, et d’autre part les performances de ponte. Le suivi de la croissance des poulets a été effectué sur 204 poussins durant 17 semaines d’élevage (de mars à juin 2011). A 12 semaines d’âge, le taux de mortalité était de 9,31 % et l’indice de consommation était de 4,03. La modélisation de la courbe de croissance au moyen des équations de Gompertz a permis d’obtenir les relations suivantes : pour les mâles : Y(g)=2409e^((-3,68)〖 e〗^((-0,0260 t) ) ) pour les femelles : Y(g)=1835e^((-3,71)〖 e〗^((-0,0294 t) ) ) avec y, le poids corporel en grammes et t, l’âge des animaux en jours. Les performances de ponte ont été étudiées chez 38 poules durant 52 semaines (d’août 2011 à août 2012). En moyenne, la ponte débute à l’âge de 166 jours à un poids corporel de 1334g. La poule pond en moyenne 173 œufs par an d’un poids moyen variant avec l’âge de la poule, de 44 à 53g. Au vu de ces résultats, il apparaît que les poules locales de Bejaia constituent un réservoir génétique prometteur tant pour leurs performances de croissance que de ponte. Les données obtenues dans cette étude permettent d'envisager un usage des poules locales dans le cadre d'une production de qualité différenciée, en élevage pur ou en croisement. La selection de ce réservoir génétique permettra de produire une véritable race sur base de la population locale, ayant fixés les caractères désirés et reconnus par les éleveurs comme étant propres à la poule locale. [less ▲]

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