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See detailAssessing variability of literature based methane indicator traits in a large dairy cow population
Kandel, Purna Bhadra ULg; Gengler, Nicolas ULg; Soyeurt, Hélène ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2015), 19(1), 11-19

Description du sujet. La production laitière est reconnue comme une des sources majeures d’émissions de méthane (CH4). Le recours à un programme de sélection spécifique pourrait être une bonne méthode ... [more ▼]

Description du sujet. La production laitière est reconnue comme une des sources majeures d’émissions de méthane (CH4). Le recours à un programme de sélection spécifique pourrait être une bonne méthode pour optimiser les émissions de méthane par les vaches laitières. Le développement d’un tel programme nécessiterait un nombre important d’enregistrements relatifs aux émissions de méthane. Malheureusement, aucune méthode pratique et bon marché n’existe actuellement pour créer une telle base de données. Cependant, quatre indicateurs CH4 basés sur les quantités en acides gras dans la matière grasse laitière ont été recensés dans la littérature. Objectifs. L’objectif de cette étude est d’utiliser ces indicateurs de la littérature afin d’apprécier la variabilité des émissions de méthane éructées par les vaches laitières. Méthode. Ces indicateurs utilisent les quantités en acides gras obtenues par chromatographie en phase gazeuse. Comme ce type de données n’est pas disponible pour toute la population laitière, un échantillon de 602 analyses chromatographiques a été créé dans cette étude afin de développer une équation de calibrage permettant de prédire les quantités de méthane émises à partir du spectre moyen infrarouge (MIR) du lait qui est disponible pour toutes les vaches étudiées. Ensuite, l’équation de calibrage ainsi obtenue a été appliquée sur 604 028 données spectrales enregistrées entre 2007 et 2011 auprès de 70 872 vaches au cours de leurs trois premières lactations afin de prédire les quantités de méthane émises. Les paramètres génétiques de ces nouveaux indicateurs méthane prédits par MIR ont également été estimés en utilisant un modèle animal de type jour de test avec régressions aléatoires. Résultats. Ces quantités prédites par MIR variaient selon une gamme attendue s’étalant entre 350 ± 40 et 449 ± 65 g par jour. L’émission prédite moyenne de CH4 en g par jour augmentait au début de la lactation, atteignait sa plus haute concentration au pic de lactation et ensuite diminuait jusqu’à la fin de la lactation. Les héritabilités journalières moyennes variaient entre 0,29-0,35 ; 0,26-0,40 et 0,22-0,37 pour les différents indicateurs méthane étudiés au cours des trois premières lactations. Les plus grandes différences entre les valeurs d’élevage estimées pour des taureaux ayant des filles en production émettant le plus et le moins de méthane étaient de 24,18 ; 29,33 et 27,77 kg par lactation pour les trois premières lactations. Des corrélations faiblement négatives ont été observées entre les indicateurs CH4 et la quantité de lait. À l’inverse, des corrélations positives ont été estimées entre ces mêmes indicateurs et les taux en matières grasses et en protéines. Conclusions. Cette étude montre la possibilité de prédire des indicateurs méthane issus de la littérature et utilisant les concentrations en acides gras dans la matière grasse laitière à partir de la spectrométrie MIR. De plus, cette étude suggère également à partir des paramètres génétiques obtenus l’existence d’une variabilité phénotypique et génétique des quantités de méthane éructées par les vaches laitières Holstein. [less ▲]

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See detailAssessing wind comfort in urban planning
Reiter, Sigrid ULg

in Environment & Planning B : Planning & Design (2010), 37(5), 857-873

There are increasing concerns regarding the quality of urban public spaces. Wind is one important environmental factor that influences pedestrians’ comfort and safety. In modern cities, there are more and ... [more ▼]

There are increasing concerns regarding the quality of urban public spaces. Wind is one important environmental factor that influences pedestrians’ comfort and safety. In modern cities, there are more and more high constructions and complex forms which can involve significant problems of wind discomfort around these buildings. Today, architects and town planners need guidelines and simple design tools to take account of wind in their projects. This paper addresses the progress made towards computational fluid dynamics (CFD) simulations for assessing wind comfort in urban planning. We validated Fluent software for wind studies in urban environments by comparing our simulations results with wind tunnel tests. This validation shows that wind mean velocities around buildings can be simulated numerically with a very high degree of accuracy. Based on the results of a great number of CFD simulations, we developed a methodology and simple graphical tools to quantify critical wind speeds around buildings. This article should thus help in practice architects and town planners to design our built environment. Moreover, this paper shows how numerical modeling is now a high-performance tool to work out useful guidelines and simple design tools for urban planners. [less ▲]

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See detailAssessment and detection of pain in noncommunicative severely brain-injured patients.
Schnakers, Caroline ULg; Chatelle, Camille ULg; Majerus, Steve ULg et al

in Expert Review of Neurotherapeutics (2010), 10(11), 1725-31

Detecting pain in severely brain-injured patients recovering from coma represents a real challenge. Patients with disorders of consciousness are unable to consistently or reliably communicate their ... [more ▼]

Detecting pain in severely brain-injured patients recovering from coma represents a real challenge. Patients with disorders of consciousness are unable to consistently or reliably communicate their feelings and potential perception of pain. However, recent studies suggest that patients in a minimally conscious state can experience pain to some extent. Pain monitoring in these patients is hence of medical and ethical importance. In this article, we will focus on the possible use of behavioral scales for the assessment and detection of pain in noncommunicative patients. [less ▲]

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See detailAssessment and management of aortic stenosis [Evaluation et traitement de la sténose aortique]
Pirlet, C.; Magne, Julien ULg; Lancellotti, Patrizio ULg et al

in Revue Medicale Suisse (2011), 7(306), 1606-1611

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See detailAssessment and mechanism of variations in pubertal timing in internationally adopted children: a developmental hypothesis
Domine, Françoise ULg; Parent, Anne-Simone ULg; Rasier, Gregory et al

in European Journal of Endocrinology (2006), 155(Suppl. 1), 17-25

During the past decades, children migrating for international adoption have increased in number, creating an original condition of dramatic environmental change during development. In several countries ... [more ▼]

During the past decades, children migrating for international adoption have increased in number, creating an original condition of dramatic environmental change during development. In several countries, cohorts of these subjects have been shown to experience a global advancement in age at the onset of puberty, and sexual precocity is seen more frequently than in other conditions. Such early or precocious development has been assessed in relatively small cohorts or individual patients using well-defined physical indicators in comparison with updated references in the foster country. Family and adolescent evaluation of pubertal timing could allow for the study of large series of internationally adopted subjects. Also, this type of assessment integrates the physical changes of puberty with the adolescent changes in psychological and social functioning. The pathophysiological mechanisms leading to advancement of puberty in migrating children are still unclear and possibly involve several factors. In the present paper, we hypothesize that the sexual precocity in children migrating for international adoption could represent a developmentally programmed disorder resulting from cumulative anomalies in early remodeling of the central nervous system by communicational, social, nutritional, and hormonal inputs. There is some evidence that the deviations in those inputs can result in altered brain structure, particularly in the limbic system. We discuss the possible association with further disorders of developmental functions, such as cognitive, psychosocial, and sexual maturation. Along this hypothesis, some forms of idiopathic sexual precocity could result from dysfunction of one or several of the environmental programming factors, while other forms may involve predominantly genetic or familial factors. [less ▲]

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See detailAssessment and monitoring of forest-game balance: an exclosure experiment
Lehaire, François ULg; Licoppe, Alain ULg; Lejeune, Philippe ULg

Poster (2013, August)

During the last decades, populations of large ungulates have largely increased, strengthening the pressure exerted by these species on forest vegetation. Therefore, monitoring this pressure has become ... [more ▼]

During the last decades, populations of large ungulates have largely increased, strengthening the pressure exerted by these species on forest vegetation. Therefore, monitoring this pressure has become unavoidable for sustainable forest management. Such monitoring requires a rigorous approach in order to evaluate objectively the balance between game population and forestry. The use of exclosure experiment offers an interesting solution to observe the effects of game populations on forest ecosystem. When objectives expected from forest management are clearly defined, exclosure experiments can effectively be used as a monitoring tool, to allow detecting unbalanced situations, for example, herbivore pressure threatening forest regeneration. The monitoring tool combines on one side an exclosure, defined as "the real environment", fully accessible to herbivores and, on the other side an enclosure, which is the "control treatment", fenced and therefore unavailable to any large ungulates. Our main aim was to compute a set of indicators characterizing the ecological changes due to large herbivores pressure on forest ecosystems. We identified 2 categories of ecological indicators: the short-term and the medium-term indicators. Short-term indicators require only two-year of monitoring to correctly quantify herbivore pressure whereas medium-term indicators require at least 4 years of monitoring. The study site is located in Southern Belgium (Wallonia), in mixed beech and oak forests. The predominant vegetation type is the "Luzulo-Fagetum", typically found in acidophileous beech forests. The ungulate species of interest are red deer, roe deer, wild boar and mouflon. In 2006, enclosures and exclosures (4 x 4 m) were installed in 17 sites scattered in two zones with contrasted deer densities to assess indicators efficiency. Between 2006 and 2012, we performed floristic surveys and we recorded the height, density and cover of the understory vegetation of every plot. [less ▲]

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See detailAssessment and monitoring of soil quality using indices based on near infrared reflectance (NIR) spectroscopy
Cécillon, Lauric; Barthès, Bernard; Gomez, Cécile et al

in European Journal of Soil Science (2009), 60(5), 770-784

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See detailAssessment and spatial characterization of pastoral resources in northern Morocco
Chebli, Youssef; Chentouf, Mouad; Cabaraux, Jean-François ULg

in Proceedings of the 1st FARAH Day, Faculty of Veterinary Medicine (2014)

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See detailAssessment Demands of the Second Language Curricula of Belgium’s French-Speaking Secondary Schools
Noiroux, Kevin ULg

Conference (2014, July)

The second language curricula of Belgium’s French-speaking community demand that secondary school teachers administer two yearly summative assessments of five skills, which forces them to overlook ... [more ▼]

The second language curricula of Belgium’s French-speaking community demand that secondary school teachers administer two yearly summative assessments of five skills, which forces them to overlook formative assessments. [less ▲]

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See detailASSESSMENT LAND DEGRADATION USING OPTICAL REMOTE SENSING AND GIS IN SALOUM ESTUARY, SENEGAL
Dieng, Ndeye Maguette ULg

Conference (2012, July)

The present study aims at assessing consequences of salinization during the last three decades in this estuary with regard to land, biodiversity and water degradation. In this respect, Landsat images ... [more ▼]

The present study aims at assessing consequences of salinization during the last three decades in this estuary with regard to land, biodiversity and water degradation. In this respect, Landsat images (1984, 1992, 1999 and 2010) were used to investigate regional time series land use/land cover. These were classified into six land-use/land-cover types: water bodies, high mangrove, low mangrove, denuded and salty soils (locally called “Tan”), savannah/rainfed agriculture and forestland. Change detection analysis of land and mangrove degradation was assessed using GIS techniques. Spectral analysis indicated that from 1984 to 2010, mangroves and savannah/rainfed agriculture are converted to “tan” (denuded and salty soils). In addition, these results showed that significant changes in land-use/land-cover occur within the whole estuary system and reflecting therefore environmental degradation, such as land desertification and salinization, and vegetation degradation which reflect the advanced of salinity [less ▲]

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See detailAssessment methodology of the intradermal tuberculosis skin test performed in cattle by field practitioners
Humblet, Marie-France ULg; Walravens, K.; Salandre, O. et al

Poster (2010)

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See detailAssessment of a 3S rotary atomizer
Ouled Taleb Salah, Sofiene ULg; Massinon, Mathieu ULg; Lebeau, Frédéric ULg

Poster (2013, May 23)

Spinning disc sprayers were first introduced to control cotton pests and diseases. These atomizers were recognized for their production of a uniform droplet size spectrum than conventional nozzles. They ... [more ▼]

Spinning disc sprayers were first introduced to control cotton pests and diseases. These atomizers were recognized for their production of a uniform droplet size spectrum than conventional nozzles. They have proved to be the most successful way of delivering pesticides in the form of Controlled Droplet Application (CDA) at very low volume application. But they were almost abandoned since the years of 1990 for high and medium volume application. Their use was found inefficient in arable crops such as cereals due to the use of inappropriate application rate and problem of penetration of spray in cereal canopies. However, these spray generators may be the best solution when the spray was to be targeted to a small weed with hydrophobic leaf surface where adhesion in the impact is essential for treatment efficiency while minimizing drift and splash thanks to reduced droplet span. In this study, aiming to maximize the control of black grass in cereals, characterization of the droplet size spectra was performed to predict the trajectory droplet and estimate the number that will hit the targeted surface. So, a CDA Micromax Ltd rotary atomizer 3S was operated at different rotation speeds (2000, 3500 and 5000 rpm), flow rates and pressures. A camera X stream -3S which allows the acquisition images in PIV mode, connected to a led lightening set at double mode exposure, were placed in front of the edge of the disc on a spray bench. Images were treated through a laboratory developed Matlab code for Particle Tracking Velocimetry Sizing. Droplets speeds according to diameters were extracted. Droplets cumulative volume according to diameters was also obtained. As the flow rate rose, the volume median diameter (VMD) increased. On the other hand, the VMD decreased as the rotation speed increased. Satellites droplets were observed when the atomizer was operating at a disc speed of 2000 rpm. For each flow rate corresponding to a drop size VMD, the number of droplets/cm2 that will affect pesticide coverage was calculated. Thus, the number of droplets that will effectively adhere depend on their impact at the moment of their arrival to the surface target. [less ▲]

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See detailAssessment of a bone biopsy technique for measuring tiludronate in horses: A preliminary study
Delguste, Catherine ULg; Doucet, Michèle; Gabriel, Annick ULg et al

in Canadian Journal of Veterinary Research = Revue Canadienne de Recherche Vétérinaire (2011), 75(2), 128-133

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See detailAssessment of a bone biopsy technique for tiludronic acid dosage in horses: a preliminary study
Delguste, Catherine ULg; Doucet, Michèle; Gabriel, Annick ULg et al

Poster (2006, September)

Introduction Tiludronic acid as a bisphosphonate has a strong affinity for bone, making difficult the assessment of its PK profile in this deep compartment on living animals. The invasive nature of sample ... [more ▼]

Introduction Tiludronic acid as a bisphosphonate has a strong affinity for bone, making difficult the assessment of its PK profile in this deep compartment on living animals. The invasive nature of sample collection remains a limiting factor. This study was carried out in order to assess a bone biopsy technique allowing the repetition of sampling over a long period of time to dose tiludronic acid in equine bone. Material and Methods Six healthy 4- to 8-year-old Standardbred geldings were treated with tiludronic acid 1 mg/kg in a saline infusion over 30 minutes. The horses were subjected to euthanasia on days 1, 43, 57, 92, 182 and 222 post-treatment, respectively. Bone samples (test samples and larger reference samples) were taken at 4 sites per side and per horse: the lateral aspect of the metacarpal bone III (MCIII) of the forelimb, the 13th rib, the tuber coxae and the cuboïd bone. Test samples were taken with a 5-mm diameter dental drill (Implanteo™, Anthogyr), while larger reference samples were taken around the drill sample sites with an osteotome. All samples were taken immediately after euthanasia. Tiludronic acid concentrations were measured by HPLC with UV detection. Results The tuber coxae was the easiest site to sample. The sample site of the MCIII was easily accessible but due to the extreme hardness of the bone, the drill sampling was technically difficult to perform. Drill samples obtained from the 13th rib were very small, and the access more limited. Finally, the access to the cuboïd bone required considerable dissection, not performable in vivo. Extraction and dosage of tiludronic acid from the MCIII was difficult for technical reasons in most cases, in drill samples as well as in reference samples, and most (96%) of the values obtained were considered unreliable. This was also true for some samples from the 13th rib and from the cuboïd bone, to a lesser extent (42% of unreliable values for both sites). Moreover, for these two sample sites, less technical problems were encountered for the extraction and dosage of tiludronic acid in drill samples than in reference samples. No extraction or dosage problem was encountered with the tuber coxae samples. The ratio of tiludronic acid concentrations in drill versus reference samples ranged from 73% to 185% (mean: 124%), 65% to 208% (mean: 118%), and 26% to 110% (mean: 62%) respectively in the tuber coxae, 13th rib and cuboïd bone. In all but one horse, the highest concentrations in tiludronic acid were found in the tuber coxae, while the lowest values tended to be in the cuboïd bone at any time post-treatment. Tiludronic acid was still found in all bone samples 7 months after treatment. Discussion As previously reported with other tools, the drill tested in this study should permit to conveniently perform bone biopsies in the equine tuber coxae. This biopsy site would be the most appropriate for repeated sampling to dose tiludronic acid over time. This would help to design appropriate PK/PD studies with tiludronic acid in horses. This study also further confirms the long persistence of tiludronic acid in equine bone. [less ▲]

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See detailAssessment of a multiscale fatigue damage model associated with stress gradient effects
Duchene, Laurent ULg; Marmi, Abdeljalil ULg; Habraken, Anne ULg

Poster (2014, September)

The aim of this research work is to develop a finite element numerical tool able to predict accurately the fatigue life of mechanical components. These components can have complex geometries, they can be ... [more ▼]

The aim of this research work is to develop a finite element numerical tool able to predict accurately the fatigue life of mechanical components. These components can have complex geometries, they can be submitted to a complex loading, leading to a specific stress field with possible stress concentration. Additionally, the successive cycles of loading are not necessarily identical. It is expected that the numerical tool can handle these demanding constraints. In this respect, a multiaxial fatigue damage model was implemented in our home-made finite element code Lagamine. The finite element method permits to account for the actual geometry of the mechanical part and the loading for the stress computation in the whole structure. The formulation of the multiaxial fatigue model is able to capture: - The non linear damage accumulation for multiblock and variable cyclic loading, - The effect of the mean (hydrostatic) stress, - The effect of the cycles below the fatigue limit if the damage was previously initiated. Finally, the occurrence of stress concentration will significantly reduce the life time of the studied piece. However, it is well-known that the subsequent local degradation of the material will be partly compensated by an enhanced load carrying contribution of the surrounding material, favourably leading to a reduction of the crack propagation. The stress gradients computed with different techniques are incorporated in the model so as to account for such beneficial influence. The physical roots of this model depart from the mesoscopic length scale, where the damage evolution is related to the mesoscopic accumulated plastic strain. Therefore, the variables of the model are defined at both macroscopic and mesoscopic scales and a specific scale transition method was implemented, based on the well-known simplified Zarka method but used at the multiscale level. The predictive capabilities of this multiscale multiaxial model are assessed by means of comparison with the classical Lemaitre-Chaboche model (implemented in the same FE code with stress gradient effects). For both models, the material parameters were identified from SN tests on smooth specimens of Ti-6Al-4V alloy, while the predictions of the models are validated thanks to comparison with experimental tests on notched samples, with stress gradient effects. [less ▲]

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See detailassessment of acid base imbalances in horses suffering from atypical myopathy
Van Galen, Gaby ULg; Cerri, Simona ULg; Porter, Sarah et al

in proceedings AAEP 2011 (2011, November 11)

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See detailAssessment of an anomaly detector for jet engine health monitoring
Borguet, Sébastien ULg; Léonard, Olivier ULg

in International Journal of Rotating Machinery (2011), 2011

The goal of module performance analysis is to reliably assess the health of the main components of an aircraft engine. A predictive maintenance strategy can leverage this information to increase ... [more ▼]

The goal of module performance analysis is to reliably assess the health of the main components of an aircraft engine. A predictive maintenance strategy can leverage this information to increase operability and safety as well as to reduce costs. Degradation undergone by an engine can be divided into gradual deterioration and accidental events. Kalman filters have proven very efficient at tracking progressive deterioration but are poor performers in the face of abrupt events. Adaptive estimation is considered as an appropriate solution to this deficiency. This paper reports the evaluation of the detection capability of an adaptive diagnosis tool on the basis of simulated scenarios that may be encountered during the operation of a commercial turbofan engine. The diagnosis tool combines a Kalman filter and a secondary system that monitors the residuals. This auxiliary component implements a generalised likelihood ratio test in order to detect abrupt events. [less ▲]

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