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See detailThe internet as a source of information used by women after childbirth to meet their need for information: A web-based survey.
Slomian, Justine ULg; Bruyère, Olivier ULg; Reginster, Jean-Yves ULg et al

in Midwifery (2017), 48

OBJECTIVE: the aims of this survey were: (a) to evaluate the need of information after childbirth and what questions do 'new' mothers ask themselves; (b) to assess why and how women use the Internet to ... [more ▼]

OBJECTIVE: the aims of this survey were: (a) to evaluate the need of information after childbirth and what questions do 'new' mothers ask themselves; (b) to assess why and how women use the Internet to meet their need of information; (c) to describe how the respondents evaluate the reliability of the information found; (d) to understand how the information found on the Internet affects women's decision-making; and (e) to appreciate how health professionals react to the information found by the women. DESIGN: this study used a large web-based survey that was widely broadcasted on various websites and social networks. SETTING AND PARTICIPANTS: belgian women who had a child under 2 years old and who agreed to participate were included in the study. FINDINGS: 349 questionnaires were valid for analyses. After childbirth, 90.5% of women admitted to using the Internet to seek information about themselves or about their baby, regardless of socioeconomic status or age. There were various reasons for seeking information on the Internet, but the most frequent reason the women expressed was to find information 'on their own' (88.1%). The most searched for topic was breastfeeding. The women believed that the information was quite useful (82.7%) but they assigned an average score of 5.3 out of 10 for the quality of the information they found on the Internet. Approximately 80% of the women felt that the Internet helped them control a decision that they made 'a little', 'often' or 'very often'. Professionals are not always willing to talk about information found on the Internet with mothers. Therefore, many women believed that health professionals should suggest reliable Internet websites for new mothers. CONCLUSIONS: the integration of the Internet and new technologies could be a useful tool during postpartum management. [less ▲]

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See detailAdvanced method optimization for volatile aroma profiling of beer using two-dimensional gas chromatography time-of-flight mass spectrometry
Stefanuto, Pierre-Hugues ULg; Perrault, Katelynn ULg; Dubois, Lena ULg et al

in Journal of Chromatography. A (2017)

The complex mixture of volatile organic compounds (VOCs) present in the headspace of Trappist and craft beers was studied to illustrate the efficiency of thermal desorption (TD) comprehensive two ... [more ▼]

The complex mixture of volatile organic compounds (VOCs) present in the headspace of Trappist and craft beers was studied to illustrate the efficiency of thermal desorption (TD) comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) for highlighting subtle differences between highly complex mixtures of VOCs. Headspace solid-phase microextraction (HS-SPME), multiple (and classical) stir bar sorptive extraction (mSBSE), static headspace (SHS), and dynamic headspace (DHS) were compared for the extraction of a set of 21 representative flavor compounds of beer aroma. A Box-Behnken surface response methodology experimental design optimization (DOE) was used for convex hull calculation (Delaunay’s triangulation algorithms) of peak dispersion in the chromatographic space. The predicted value of 0.5 for the ratio between the convex hull and the available space was 10% higher than the experimental value, demonstrating the usefulness of the approach to improve optimization of the GC × GC separation. Chemical variations amongst aligned chromatograms were studied by means of Fisher Ratio (FR) determination and F‐distribution threshold filtration at different significance levels (α = 0.05 and 0.01) and based on z‐score normalized area for data reduction. Statistically significant compounds were highlighted following principal component analysis (PCA) and hierarchical cluster analysis (HCA). The dendrogram structure not only provided clear visual information about similarities between products but also permitted direct identification of the chemicals and their relative weight in clustering. The effective coupling of DHS-TD-GC × GC-TOFMS with PCA and HCA was able to highlight the differences and common typical VOC patterns among 24 samples of different Trappist and selected Canadian craft beers. [less ▲]

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See detailExperimental and Numerical Study of Mini-UAV Propeller Performance in Oblique Flow
Theys, Bart; Dimitriadis, Grigorios ULg; Hendrick, Patrick et al

in Journal of Aircraft (2017), 54(3), 1076-1084

This paper presents the modelling of the performance of small propellers used for Vertical Take Off and Landing Micro Aerial Vehicles (VTOL MAVs) operating at low Reynolds numbers and in oblique flow ... [more ▼]

This paper presents the modelling of the performance of small propellers used for Vertical Take Off and Landing Micro Aerial Vehicles (VTOL MAVs) operating at low Reynolds numbers and in oblique flow. Blade Element Momentum Theory (BEMT), Vortex Lattice Method (VLM) and momentum theory for oblique flow are used to predict propeller performance. For validation, the predictions for a commonly used propeller for VTOL MAVs are compared to a set of wind tunnel experiments. Both BEMT and VLM succeed in predicting correct trends of the forces and moments acting upon the propeller shaft, although accuracy decreases significantly in oblique flow. For the dataset analysed here, combining the available data of the propeller in purely axial flow with momentum theory for oblique flow and applying a correction factor for the wake skew angle results in more accurate performance estimates at all elevation angles. [less ▲]

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See detailExperimental passive flutter suppression using a linear tuned vibration absorber
Verstraelen, Edouard ULg; Habib, Giuseppe ULg; Kerschen, Gaëtan ULg et al

in AIAA Journal (2017), 55(5), 1707-1722

The current drive for increased efficiency in aeronautic structures such as aircraft, wind turbine blades and helicopter blades often leads to weight reduction. A con- sequence of this tendency can be ... [more ▼]

The current drive for increased efficiency in aeronautic structures such as aircraft, wind turbine blades and helicopter blades often leads to weight reduction. A con- sequence of this tendency can be increased flexibility, which in turn can lead to un- favourable aeroelastic phenomena involving large amplitude oscillations and non- linear effects such as geometric hardening and stall flutter. Vibration mitigation is one of the approaches currently under study for avoiding these phenomena. In the present work, passive vibration mitigation is applied to a nonlinear experimental aeroelastic system by means of a linear tuned vibration absorber. The aeroelastic apparatus is a pitch and flap wing that features a continuously hardening restoring torque in pitch and a linear restoring torque in flap. Extensive analysis of the sys- tem with and without absorber at pre-critical and post-critical airspeeds showed an improvement in flutter speed of around 36%, a suppression of a jump due to stall flutter, and a reduction in LCO amplitude. Mathematical modelling of the exper- imental system is used to demonstrate that optimal flutter delay is achieved when two of the system modes flutter at the same flight condition. Nevertheless, even this optimal absorber quickly loses effectiveness as it is detuned. The wind tunnel mea- surements showed that the tested absorbers were much slower to lose effectiveness than those of the mathematical predictions. [less ▲]

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See detailLes épreuves multiples chez les jeunes. Réflexion sur un programme développemental à long terme.
Jidovtseff, Boris ULg

Learning material (2017)

Réflexion personnelle sur une proposition de modèle développemental à long terme spécifique aux épreuves multiples en athlétisme.

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See detailChallenges of CO2 capture as an application of fluid separation techniques
Léonard, Grégoire ULg

Conference (2017, May)

The presentation offers a review of CO2 capture technologies presented as an application of fluid separation. CO2 capture processes (Post-combustion, pre-combustion, oxyfuel combustion and industrial ... [more ▼]

The presentation offers a review of CO2 capture technologies presented as an application of fluid separation. CO2 capture processes (Post-combustion, pre-combustion, oxyfuel combustion and industrial processes) and CO2 capture methods (absorption, adsorption, membranes...) are described, and illustrated by industrial examples of these technologies. Techno-economic challenges faced by these technologies are also mentionned, and perspectives for future developments are discussed. [less ▲]

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See detailPerceived management commitment to safety and safety behaviors: the moderating role of trust and support
Laurent, Julie ULg; Chmiel, Nik; Hansez, Isabelle ULg

Conference (2017, May)

Instrumental processes, based on the idea that individual perceptions of safety climate inform behavior outcomes expectancies (Zohar, 2008), and reciprocation processes, based on social exchange theory ... [more ▼]

Instrumental processes, based on the idea that individual perceptions of safety climate inform behavior outcomes expectancies (Zohar, 2008), and reciprocation processes, based on social exchange theory (Blau, 1964), have been identified as important processes to take into account in order to understand safety behaviors (Chmiel & Hansez, 2016). The main aim of this study is to go further in the explanation of the processes linking perceived management commitment to safety (PMCS) to safety behaviors, by testing the moderating role of two variables reflecting the way workers perceive their supervisor: safety specific trust in the supervisor, illustrating instrumental processes and perceived supervisor support (PSS), illustrating reciprocation processes. In two samples, a survey methodology and Latent Moderated Structural (LMS) equation modelling were used to test our hypotheses. Overall, and although results were mixed and discussed, high PMCS, when combined with high trust or high PSS, resulted in safer behaviors. We did not find such significant effects as explaining routine violations. The patterns of results were similar in the two samples. The main limitations are the use of single-source and self-reported data may lead to common-method variance bias and the cross-sectional nature of the study. Future longitudinal research is needed to test causality. An important implication for companies is to be aware of the powerful role played by management: building trusting relationship (by behaving consistently regarding safety) and encouraging managers to show support to their employees in a context where safety is considered as important are keys to potentially achieve safe behaviors. [less ▲]

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See detailBasic Helix loop Helix transcription factor twist1a and twist1b and their involvement in the skeletal development of zebrafish.
Zappia, Jérémie ULg; Windhausen, Thomas ULg; Renn, Jörg ULg et al

Poster (2017, May)

1. Objective The twist1a and twist1b genes code for transcription factors involved during embryogenesis in the craniofacial development. The human ortholog of twist1a and twist1b, TWIST1 has been shown to ... [more ▼]

1. Objective The twist1a and twist1b genes code for transcription factors involved during embryogenesis in the craniofacial development. The human ortholog of twist1a and twist1b, TWIST1 has been shown to be mutated in cases of the Saethre–Chotzen syndrome (SCS). However, the roles of these genes in skeletal development in zebrafish remain to be clarified. The aim of our research is to characterize the effects of the knock-down of twist1a and twist1b in the zebrafish. 2. Methods Antisens morpholino are used for the knock-down of twist1a and twist1b (respectively MoTwist1a and MoTwist1b). The sox9a expression is investigated using whole amount in situ hybridization. 3. Results We show the spatio-temporal expression pattern of twist1a and twist1b during the first 6 days of zebrafish development and present the effects observed on cartilage and bone formation upon knock-down of these genes in zebrafish larvae. The results reveal a decrease of the cranial cartilage and bone formation in both MoTwist1a and MoTwist1b. Interestingly, when MoTwist1a and MoTwist1b are co-injected, the cranial cartilage formation is strongly reduced, while ectopic cartilage formation appeared in the front of the head. We also show an increase in expression of sox9a, a master regulator of chondrogenesis, in morphants. 4. Summary and Conclusions Even though it was shown that twist1a and twist1b maintain a pool of osteoprogenitor-like cells, we show that a knock-down of these genes induces a decrease of skeletal formation. Our hypothesis is that the morphants run out of progenitor cells to assure correct bone and cartilage formation. In the future, we plan to generate twist1a mutants in order to further characterize the effect of this mutation. The twist1a mutant will eventually serve for a rescue study using human TWIST1 mRNA, wild-type or mutant in order to have a better understanding of the human disorder SCS. [less ▲]

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See detailEtude expérimentale et numérique d'un échangeur destiné à la récupération de chaleur fatale sur bancs d'essais de moteurs aéronautiques
Gendebien, Samuel ULg; Guillaume, Ludovic ULg; Bellolio Domke, Sebastian Andres ULg et al

in Colloque Inter-universitaire Franco-Québécois (CIFQ 2017), 22-24 mai 2017, Saint-Lô, France (2017, May)

Aujourd’hui, d’importants efforts sont réalisés dans divers secteurs afin de diminuer la consommation en énergie. En ce qui concerne le secteur aéronautique, de nombreux tests sont réalisés sur les ... [more ▼]

Aujourd’hui, d’importants efforts sont réalisés dans divers secteurs afin de diminuer la consommation en énergie. En ce qui concerne le secteur aéronautique, de nombreux tests sont réalisés sur les moteurs afin d’assurer la sécurité du transport aérien. Dans ce contexte, il a été envisagé de récupérer, recycler et valoriser l’énergie produite par le moteur au moyen d’un échangeur placé dans la cheminée d’évacuation des gaz. Pour ce faire, un prototype de modèle réduit d’échangeur récupératif sur gaz de combustion (gaz/eau ou gaz/huile) a été conçu, fabriqué et testé. Ce papier présente les caractéristiques du modèle réduit de l’échangeur développé spécifiquement pour cette application. L’ensemble du banc d’essais et le système de mesure mis en place afin de caractériser les performances de l’échangeur sont décrits. Une analyse des résultats expérimentaux est présentée. Les tests sont notamment divisés en deux parties : établissement des performances en régime monophasique et diphasique. Notons également que les performances hydrauliques de l’échangeur ont été expérimentalement déterminées. Un modèle numérique de type semi-empirique est proposé pour prédire les performances de l’échangeur. Ce dernier nécessite un calibrage des paramètres au moyen des données expérimentales afin de prédire les performances de l’échangeur sous une grande plage de conditions opératoires. Une comparaison entre résultats numériques et expérimentaux est finalement présentée. [less ▲]

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See detailGérer le changement: une dynamique multidimensionnelle et participative
Lisein, Olivier ULg

Scientific conference (2017, May)

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See detailL'intrapreneuriat, vecteur de nouvelles formes de collaborations ?
Lisein, Olivier ULg

Conference (2017, May)

Intervention sur les enjeux, les challenges et les bénéfices potentiels de l'intrapreneuriat comme vecteur d'innovations et de collaborations pour et au sein des entreprises. Intervention réalisée lors de ... [more ▼]

Intervention sur les enjeux, les challenges et les bénéfices potentiels de l'intrapreneuriat comme vecteur d'innovations et de collaborations pour et au sein des entreprises. Intervention réalisée lors de la table ronde "Interview d’experts: Les nouvelles pratiques de management dans l’entreprise collaborative" dont le fil conducteur est résumé comme suit : "Face à un marché en pleine mutation, nous verrons lors de cette table ronde quelles actions de management les entreprises mettent en place pour valoriser les individus et développer leurs compétences, mais aussi pérenniser une relation empreinte d’autonomie". [less ▲]

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See detailIsotopic half-life and enrichment factor in two species of European freshwater fish larvae: an experimental approach
Latli, Adrien; Sturaro, Nicolas ULg; Dujardin, Nelson et al

in Rapid Communications in Mass Spectrometry (2017), 31(8), 685-692

RATIONALE: Stable isotope ratios of carbon and nitrogen are valuable tools for field ecologists to use to analyse animal diets. However, the application of these tools requires knowledge of the tissue ... [more ▼]

RATIONALE: Stable isotope ratios of carbon and nitrogen are valuable tools for field ecologists to use to analyse animal diets. However, the application of these tools requires knowledge of the tissue enrichment factor (TEF) and half-life (HL). We experimentally compared TEF and HL in two freshwater fish larvae. We hypothesised that chub had a better growth/tissue replacement ratio than roach, due to the use of a food closer to their natural diet. METHODS: We determined the isotopic HL, the TEF and the contribution of growth or metabolic tissue replacement to dynamic isotopic incorporation. After yolk sac resorption, larvae were fed for 5 weeks with prey similar to their natural diet (Artemia nauplii) up to the isotopic equilibrium followed by Chironomid larvae. Stable isotope measurements were carried out using a continuous flow isotope ratio mass spectrometer coupled to an elemental analyser. RESULTS: Changes in isotopic composition strongly followed the predictions of exponential growth and time-dependent models. The isotopic HL varied between 8.2 and 12.6 days and the TEF of nitrogen and carbon ranged from 1.7 to 2.1‰ and from –0.9 to 1.2 ‰, respectively. The incorporation of dietary 13C was due more to the production of new tissue (between 56 and 79%) than to the metabolic process. Chub allocated more energy to growth than roach and the Chironomidae diet contributed more to the consumers’ growth than the Artemia diet. CONCLUSIONS: Metabolic rates seemed lower for chub than for roach, especially when they were fed with Chironomidae. A Chironomidae-based diet would be more profitable to chub, and the high associated growth rate could increase the development of the fish larvae. The HL and TEF were in the range of those reported in the literature. These results will be helpful for field-based studies, because they can help to increase the accuracy of models. [less ▲]

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See detailL'enseignement-apprentissage du français dans le qualifiant : regards croisés
Scheepers, Caroline ULg; Outers, Pierre ULg; Werner, Anne-Catherine ULg

Poster (2017, April 29)

La présentation donne à voir les résultats partiels d'une recherche exploratoire qui a consisté à questionner les élèves et les professeurs de l'enseignement secondaire de transition et du qualifiant à ... [more ▼]

La présentation donne à voir les résultats partiels d'une recherche exploratoire qui a consisté à questionner les élèves et les professeurs de l'enseignement secondaire de transition et du qualifiant à propos de leurs représentations relatives à l'enseignement-apprentissage du français dans le qualifiant. Pour l'heure, nous disposons des réponses apportées par 30 enseignants et par 450 élèves. A terme, cinquante enseignants et 1000 élèves sont concernés. [less ▲]

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See detailDes preuves : où, quand, comment ?
Rigo, Michel ULg

Speech/Talk (2017)

Expliquer une démonstration, prouver un résultat, énoncer une conjecture sont des activités qui font partie intégrante du quotidien du mathématicien. Dans ce court exposé, je passerai en revue quelques ... [more ▼]

Expliquer une démonstration, prouver un résultat, énoncer une conjecture sont des activités qui font partie intégrante du quotidien du mathématicien. Dans ce court exposé, je passerai en revue quelques exemples de preuves. Certaines sont classiques ou historiques, d'autres sont peut-être moins connues : des preuves à la Ramanujan, des preuves sans mots, le théorème des quatre couleurs, la conjecture de Klepler sur l'empilement de sphères,... Le but est de partager mes réflexions comme chercheur « professionnel » et enseignant. [less ▲]

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See detailThe Prediction-Focused Approach: An opportunity for hydrogeophysical data integration and interpretation
Hermans, Thomas ULg; Nguyen, Frédéric ULg; Klepikova, Maria et al

Conference (2017, April 28)

Hydrogeophysics is an interdisciplinary field of sciences aiming at a better understanding of subsurface hydrological processes. If geophysical surveys have been successfully used to qualitatively ... [more ▼]

Hydrogeophysics is an interdisciplinary field of sciences aiming at a better understanding of subsurface hydrological processes. If geophysical surveys have been successfully used to qualitatively characterize the subsurface, two important challenges remain for a better quantification of hydrological processes: (1) the inversion of geophysical data and (2) their integration in hydrological subsurface models. The classical inversion approach using regularization suffers from spatially and temporally varying resolution and yields geologically unrealistic solutions without uncertainty quantification, making their utilization for hydrogeological calibration less consistent. More advanced techniques such as coupled inversion allow for a direct use of geophysical data for conditioning groundwater and solute transport model calibration. However, the technique is difficult to apply in complex cases and remains computationally demanding to estimate uncertainty. In a recent study, we investigate a prediction-focused approach (PFA) to directly estimate subsurface physical properties from geophysical data, circumventing the need for classic inversions. In PFA, we seek a direct relationship between the data and the subsurface variables we want to predict (the forecast). This relationship is obtained through a prior set of subsurface models for which both data and forecast are computed. A direct relationship can often be derived through dimension reduction techniques. PFA offers a framework for both hydrogeophysical “inversion” and hydrogeophysical data integration. For hydrogeophysical “inversion”, the considered forecast variable is the subsurface variable, such as the salinity. An ensemble of possible solutions is generated, allowing uncertainty quantification. For hydrogeophysical data integration, the forecast variable becomes the prediction we want to make with our subsurface models, such as the concentration of contaminant in a drinking water production well. Geophysical and hydrological data are combined to derive a direct relationship between data and forecast. We illustrate the process for the design of an aquifer thermal energy storage (ATES) system. An ATES system can theoretically recover in winter the heat stored in the aquifer during summer. In practice, the energy efficiency is often lower than expected due to spatial heterogeneity of hydraulic properties combined to a non-favorable hydrogeological gradient. A proper design of ATES systems should consider the uncertainty of the prediction related to those parameters. With a global sensitivity analysis, we identify sensitive parameters for heat storage prediction and validate the use of a short term heat tracing experiment monitored with geophysics to generate informative data. First, we illustrate how PFA can be used to successfully derive the distribution of temperature in the aquifer from ERT during the heat tracing experiment. Then, we successfully integrate the geophysical data to predict medium-term heat storage in the aquifer using PFA. The result is a full quantification of the posterior distribution of the prediction conditioned to observed data in a relatively limited time budget. [less ▲]

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See detailL’espace public comme tribune
Brahy, Rachel ULg

Conference given outside the academic context (2017)

L’espace public a de tous temps été une tribune, un lieu où débattre, haranguer la foule, partager des opinions ou rassembler des soutiens. Le chapiteau de cirque et l’art dans la rue occupent cet espace ... [more ▼]

L’espace public a de tous temps été une tribune, un lieu où débattre, haranguer la foule, partager des opinions ou rassembler des soutiens. Le chapiteau de cirque et l’art dans la rue occupent cet espace sans pour autant l’utiliser comme tribune. La présentation d’un spectacle à un public implique pourtant des questions de mise en scène qui sont déjà une forme d’engagement, celui de l’artiste au service de sa création. Il n’y a alors plus qu’un petit pas à franchir pour se poser la question de l’engagement de l’artiste dans le monde. Avec Didier Balsaux, Directeur artistique des Royales Marionnettes ; Alain Moreau, Directeur du Tof théâtre ; Sara Amari, Thank You for Coming ; Charles Culot, auteur de “Nourrir l’humanité” ; Rachel Brahy, Coordinatrice scientifique de la Maison des Sciences de l’Homme Ulg ; … Modérateur : Antoine Laubin, Co-directeur éditorial de la revue Alternatives théâtrales Rapporteuse: Laurence Bertels [less ▲]

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See detailStreamlining NCA independence in reforming Regulation 1/2003: time to take incongruent accountability realities (more) seriously?
Van Cleynenbreugel, Pieter ULg

Scientific conference (2017, April 28)

This presentation analyses argues that the Commission’s reform suggestions aimed at streamlining NCAs into independent administrative agencies appear to neglect this variety of accountability mechanisms ... [more ▼]

This presentation analyses argues that the Commission’s reform suggestions aimed at streamlining NCAs into independent administrative agencies appear to neglect this variety of accountability mechanisms underlying current NCA institutional organisation and functioning. Given that those mechanisms each harbour incongruent expectations regarding the organisation and functioning of independent NCAs, failure to acknowledge such incongruence may in practice lead to less effective competition law enforcement. Its purpose is therefore to uncover the different NCA independence perspectives underlying those accountability mechanisms and to look for legally sound ways to make them converge when designing or upgrading NCA independence in the context of the Regulation 1/2003 reform. [less ▲]

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