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See detailElastic damage to crack transition in a coupled non-local implicit discontinuous Galerkin/extrinsic cohesive law framework
Wu, Ling ULg; Becker, Gauthier ULg; Noels, Ludovic ULg

in Computer Methods in Applied Mechanics & Engineering (2014), 279

One current challenge related to computational fracture mechanics is the modeling of ductile fracture and in particular the damage to crack transition. On the one hand, continuum damage models, especially ... [more ▼]

One current challenge related to computational fracture mechanics is the modeling of ductile fracture and in particular the damage to crack transition. On the one hand, continuum damage models, especially in their non-local formulation which avoids the loss of solution uniqueness, can capture the material degradation process up to the localization of the damage, but are unable to represent a discontinuity in the structure. On the other hand cohesive zone methods can represent the process zone at the crack tip governing the crack propagation, but cannot account for the diffuse material damaging process. In this paper we propose to combine, in a small deformations setting, a non-local elastic damage model with a cohesive zone model. This combination is formulated within a discontinuous Galerkin nite element discretization. Indeed this DG weak formulation can easily be developed in a non-local implicit form and naturally embeds interface elements that can be used to integrate the traction separation law of the cohesive zone model. The method remains thus consistent and computationally e cient as compared to other cohesive element approaches. The effects of the damage to crack transition and of the mesh discretization are respectively studied on the compact tension specimen and on the double-notched specimen, demonstrating the efficiency and accuracy of the method. [less ▲]

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See detailTechnical variability in the Gravettian with tanged tools: new results from Belgium
Touzé, Olivier; Flas, Damien ULg; Pesesse, Damien

Conference (2014, September 01)

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See detailPredictive microbiology combined with metagenomic analysis targeted on the 16S rDNA : A new approach for food quality
Delhalle, Laurent ULg; Ellouze, Mariem; Taminiau, Bernard ULg et al

Poster (2014, September 01)

The food spoilage process is mainly caused by alteration micro-organisms and classical culture-based methods may not be relevant to understand the modifications of the microbial ecology in food products ... [more ▼]

The food spoilage process is mainly caused by alteration micro-organisms and classical culture-based methods may not be relevant to understand the modifications of the microbial ecology in food products. Metagenomic analysis targeted on 16S ribosomal DNA can elucidate microbial community structures at a muche higher resolution than was previously possible. Combined with predictive microbiological models, a new approach was investigated to take into account bacterial populations dynamics in perishable foods under different environmental conditions. White pudding samples, a typical Belgian pork meat product, were packed under food wrap (atmospheric air condition). Durability studies were conducted at 4°C, 12°C and a dynamic temperature profile according to the NF V01-003 standards (4°C (1/3 of the shelf life) - 8°C (2/3 of the shelf life)) during 15 days. The effect of organic acids was also investigated using a lactic acid (1.8% w/w) treatment. At each day of the trials, classical microbiological (total flora) and 16S rDNA metagenomic analysis were carried out on all these samples. For the metagenomic analysis, a sequencing library was generated, targeting the V1-V3 region of the 16S rDNA. The two major bacterial populations were thus identified (Psychrobacter sp and Brochotrix thermosphacta) and predictive microbiology models used to assess the growth parameters. Cardinal parameters for temperature were collected on the two main bacterial species. The model was validated using the data obtained at a dynamic temperature profile. The results of the simulations for Psychrobacter sp and Brochotrix thermosphacta show a good compliance between predicted and observed data. Compared to culture based methods on selective media and previous independent culture techniques, metagenomic analysis combined with predictive microbiology gives more valuable information, and could be considered as a technological breakthrough to control the quality or for accurately determining shelf life. [less ▲]

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See detailFraming and Political Discourse Analysis: Bush's Trip to Europe in 2005
Azpíroz Manero, María Luisa ULg

in Observatorio (OBS*) (2014), 8(3), 075-96

Framing empirical research analyzes the construction (frame building) and influence (frame effects) of the frames with which different social agents interpret and communicate reality. Based on Entman’s ... [more ▼]

Framing empirical research analyzes the construction (frame building) and influence (frame effects) of the frames with which different social agents interpret and communicate reality. Based on Entman’s (2004; 2008) and Kuypers’ (2008; 2009) contributions, this paper proposes and applies a qualitative methodology for the analysis of frame building in political discourse. It is located, therefore, on the strategic and methodological lines of framing research in political communication (Bartolomé; Rodríguez & Sádaba, 2012). As Kinder and Sanders state, frames are “invented and employed by political elites, often with an eye on advancing their own interests or ideologies, and intended to make favorable interpretations prevail” (Kinder & Sanders, 1990, p. 74). The paper includes a theoretical framework that reviews the evolution of framing literature in Communication, focusing especially on empirical studies. The contributions adopted for the elaboration of the methodology and the application process are explained in detail. The context of the case study, Bush’s discourse about the War on Terror on his trip to Europe in February 2005, is revised. Finally, the results obtained and the conclusions are detailed. [less ▲]

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See detailMultilocus sequence typing analysis and antibiotic resistance of Clostridium difficile strains isolated from retail meat and humans in Belgium
Rodriguez Diaz, Cristina ULg; Taminiau, Bernard ULg; Avesani, Véronique et al

in Food Microbiology (2014), 42

Clostridium difficile has been isolated from food animals and meat, specially ground pork and ground beef. The recovered isolates were closely related to C. difficile human strains, indicating that ... [more ▼]

Clostridium difficile has been isolated from food animals and meat, specially ground pork and ground beef. The recovered isolates were closely related to C. difficile human strains, indicating that animals and food are possible transmission routes of human C. difficile infection. The main objective of this study was to characterize C. difficile isolates from retail meat and to compare with human isolates recovered from hospital patients in Belgium. Raw meat (beef and pork) was obtained from the retail trade. C. difficile was recovered from 2.3% of the beef samples and from 4.7% of the pork samples. A total of 4 different PCR-ribotypes were identified with a large percentage of types 078 and 014. Resistance to moxifloxacin and erythromycin was detected. The multi-locus sequence typing (MLST) analysis showed that meat and human isolates cluster in the same lineage. This study reveals the presence of toxigenic C. difficile in retail meat in Belgium with predominance PCR-ribotypes 078 and 014, which are among the four most prevalent ribotypes of C. difficile isolated from humans in Europe. [less ▲]

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See detailUne frontière comme lieu de mémoire : l'espace frontalier belgo-allemand
Brüll, Christoph ULg

Article for general public (2014)

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See detailSelecting job candidates who have a propensity to exhibit change-oriented organizational citizenship behaviour.
Lothe, Benoit ULg; Hansez, Isabelle ULg

Conference (2014, September)

Purpose An abundant literature indicates that Organizational Citizenship Behaviours (OCBs) positively influence a number of important organizational outcomes. Furthermore, research is needed on the topic ... [more ▼]

Purpose An abundant literature indicates that Organizational Citizenship Behaviours (OCBs) positively influence a number of important organizational outcomes. Furthermore, research is needed on the topic of assessing and selecting applicants who have a propensity to exhibit OCB (Organ & al., 2010). Some of these behaviours are truly important to enable organization to adapt and “to make constructive changes in the work and task environment” (Choi, 2007, p.468). Examples include Voice, a challenging dimension of OCB (Dominguez & al., 2013), and Sportsmanship, that facilitate the change by reducing the diversion of resources in trivial matters (Organ & al., 2006). This exploratory study provides empirical evidence about using Situational Judgment Tests (SJTs) for identifying applicants who have a propensity to exhibit change oriented OCB. Method Two SJTs were developed to comply with OCBs assessment. The OCBs framework includes behaviours relating to organizational adaptation (sportsmanship) and change (voice). OCBs were concurrently collected using self-reported measurement scales. Data were collected from 220 white collars and 139 university students through an online survey. Results Significant correlations were found between the SJT scores and overall OCB ratings. More specifics findings provided substantial evidence for the concurrent validity of the SJTs to measure change-oriented sub-dimensions of OCBs. Conclusions Researches on techniques to predict OCBs are scarce and this study is the first to address the development and validation of a SJT for the assessment of affiliative and challenging dimensions of OCBs. [less ▲]

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See detailA Multiphysics model of neotissue growth in a perfu sion bioreactor
Guyot, Yann ULg; Papantoniou, Ioannis; Schrooten, Jan et al

Conference (2014, September)

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See detailL’impact de certains choix didactiques sur la performance en expression écrite et l’efficacité du feedback correctif
Noiroux, Kevin ULg; Simons, Germain ULg

in Babylonia (2014)

Many teachers use written corrective feedback, a teaching practice that consists in correcting the lexico-grammatical errors of the student’s written production. Due to its time-consuming nature for the ... [more ▼]

Many teachers use written corrective feedback, a teaching practice that consists in correcting the lexico-grammatical errors of the student’s written production. Due to its time-consuming nature for the teacher, it makes sense to strive to make corrective feedback as effective as possible. In this exploratory study, we collaborated with a high school teacher of Federation Wallonia-Brussels to create a didactic sequence that aimed at assessing the efficacy of corrective feedback in a fifth-year class. Students’ answers to a survey, as well as their written production performance, seem to point out that some pedagogical choices may have had a negative impact on the performance of corrective feedback. We underline (1) the lack of lexico-grammatical training exercises, (2) the absence of testing on lexico-grammatical knowledge, (3) the lack of work on ideas that can be transferred to the final production, (4) the lack of work on the text type and (5) the limits of formative assessment. The underlying assumption is that students’ written production performance, hence the efficacy of corrective feedback, can be improved through those didactic choices. [less ▲]

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See detailAutomatization of mirror - tracing skill in children with Developmental Coordination Disorder
Lejeune, Caroline ULg; Meulemans, Thierry ULg; Desmottes, Lise ULg et al

Poster (2014, September)

Aim: This study investigated the hypothesis of a skill automatization deficit in Developmental Coordination Disorder (DCD). Method: Thirty children (15 with DCD and 15 control children), aged between 7 ... [more ▼]

Aim: This study investigated the hypothesis of a skill automatization deficit in Developmental Coordination Disorder (DCD). Method: Thirty children (15 with DCD and 15 control children), aged between 7 and 12 years old, were administered the mirror-tracing task during two 10-trials sessions separated by one week. An auditory interference task was introduced at the end of the procedural learning phase to test skill automatization. Results: Interestingly, no between-group difference was revealed in learning and automatization measures except for a specific subgroup of DCD children (n=5) who experienced difficulties in skill automatization. Conclusion: The results of our preliminary study highlighted the heterogeneity of the deficit presented in DCD and they emphasized the importance to explore further the lack of automatization in DCD. [less ▲]

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See detailEmbargo russe sur les aliments européens : l'Europe doit montrer l'exemple
Habran, Maxime ULg

E-print/Working paper (2014)

Cette note a pour but d’apporter des éclaircissements sur les mesures en matière de politique agricole commune prises par l’Union européenne

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See detailReflexive Introduction to the Categorisation of the European Countryside
Schmitz, Serge ULg

in Siljkovic, Zeljka; Cuka, Anita; Pejdo, Ana (Eds.) Contempory development of European rural areas, Book of Abstracts (2014, September)

At the end of the 20th century, French rural geographers used a simple typology that encapsulates three categories of the countryside: Thirty years later, we should probably add new categories ... [more ▼]

At the end of the 20th century, French rural geographers used a simple typology that encapsulates three categories of the countryside: Thirty years later, we should probably add new categories: “agricultural countryside”, “recreational countryside”, “residential countryside”, “greying countryside”, “countryside supplying energy”, “new peasantry countryside”, “Biosphere reserves” and pay attention to other perspectives such as natural and cultural heritage, water resources protection and ecological transition. The paper discusses these old and new types of countryside and underlines main challenges that countryside faces; it shows how sensitive the categorisation could be according to the level of analysis, the period of observation and the perspectives. [less ▲]

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See detailImaging and understanding of iron ore granulation using X-ray mictrotomography
Evrard, Maxime ULg; Contreras, Rafael; Pirard, Eric ULg

Conference (2014, September)

Imaging and understanding of iron ore granulation using X-ray microtomography. Evrard M., Contreras R., Pirard E. Most iron ores cannot be directly fed into blast furnaces because their particle size ... [more ▼]

Imaging and understanding of iron ore granulation using X-ray microtomography. Evrard M., Contreras R., Pirard E. Most iron ores cannot be directly fed into blast furnaces because their particle size distribution will negatively impact the blast furnace permeability and hence the overall efficiency of the ore reduction process. The finest fraction (typ. < 6.3 mm) has to undergo a sintering process, wherein a mixture of iron ore, coke and flux (limestone, olivine,…) is heated, partially molten and transformed into pieces of sintered material with adequate size, porosity and strength characteristics to be fed into the blast furnace. The preparation of an adequate mixture involves a granulation process which is the subject of this study. Sintering and hence granulation of iron ores, is particularly important in Europe where iron ores show a downward trend in quality (finer particles, broader size range, lower grades with higher variability). In addition an increasing fraction of non-sintered material (return fines) is being added to the mix to optimize the resource efficiency while maintaining sinter quality. For most practitioners, microgranules (or micropellets) are considered as being composed of a nucleus (a particle in the range of 1 to 2 mm) surrounded by layers of the finest ore particles (typically the < 250 µm fraction). A series of experiments and 3D imaging tests have been performed in this study to better understand the granulation mechanisms. Microgranules are formed by mixing iron ore with water in a small rotating drum. Several parameters can be tuned during the granulation process: size and proportion of nucleating particles, size and proportion of fines, water addition, rotating speed, total duration,… Simple experiments using a single ore type (dominantly goethitic or hematitic) and water additions have been carried out systematically to better understand the kinetics of granulation. X-ray microtomography and subsequent 3D image analysis is used to identify and quantify the number of nuclei (when present), to measure the porosity and identify layering or cracks in the microgranule. Compared to previous studies on iron ore pellets (Farber et al. 2002; Shatokha et al. 2009; Shatokha et al. 2010), this work focuses on imaging prior to sintering. It also uses higher resolution micro-CT and definitely brings a better insight into granulation as compared to data from 2D imaging of polished blocks: less artefacts in apparent porosity due to sample preparation; good discrimination among components of the granule; clear identification of the nuclei; etc. This work is part of a larger European project (IMSIMI - Improved Sintering Mix) aiming at an optimal use of challenging input materials through carefully monitored preparation phases (mixing, granulation, etc.) and better understanding of their impact on the sintering process. Farber L., Tardos G., Michaels JN.,2002. Use of X-ray tomograzphy to study the porosity and morphology of granules. Powder Technology vol. 132, p 57-63. Shatokha V., Korobeynikov I., Maire E., Adrien J., 2009. Application of 3D X-ray tomography to investigation of structure of sinter mixture granules. Ironmaking and Steelmaking, vol. 36 (6), p 416-420. Shatokha V., Korobeynikov I., Maire E., Gremillard L., Adrien J.,2010. Iron ore sinter porosity characterisation with application of 3D X-ray tomography. Ironmaking and Steelmaking, vol. 37(5), p313-319. [less ▲]

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See detailComentário sobre o artigo de Pizzanelli
Jamoulle, Marc ULg

in Revista Brasileira de Medicina de Família e Comunidade (2014), 9(31),

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See detailCortical excitability dynamics of during sleep deprivation set PVT performance
Borsu, Chloé; Gaggioni, Giulia ULg; Ly, Julien ULg et al

Poster (2014, September)

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See detailApproche prothétique rationnelle et conservatrice d'usure dentaire avancée
Vanheusden, Alain ULg

in Revue d'Odonto-Stomatologie [=ROS] (2014), 43(3), 251-268

For several years, the number of young adults consulting for tooth tissue loss of non carious origin has been significantly increasing. However, many practitioners are still reluctant to treat these ... [more ▼]

For several years, the number of young adults consulting for tooth tissue loss of non carious origin has been significantly increasing. However, many practitioners are still reluctant to treat these lesions, especially when they are severe. Nevertheless, thanks to the constant improvement of the protocols of enamel and dentin bonding and a greater expertise in the field of prosthetic biomaterials, some rational, reliable and minimally invasive therapeutic approaches can often be proposed. The purpose of this article is to describe, stage by stage, a protocol of treatment based on bonded partial prosthetic restorations, both on anterior and posterior teeth. [less ▲]

Detailed reference viewed: 6 (3 ULg)