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See detailPhysical and chemical properties of pyropheophorbide)a-methyl ester in ethanol, phosphate buffer and aqueous dispersion of small unilamellar dimyristoyl-L-a-phosphatidylcholine vesicles
Delanaye, Lisiane; Bahri, Mohamed Ali ULg; Tfibel, Francis et al

in Photochemical & Photobiological Sciences (2006), 5

The aggregation process of pyropheophorbide-a methyl ester (PPME), a second generation hotosensitizer, was investigated in various solvents. Absorption and fluorescence spectra showed that the ... [more ▼]

The aggregation process of pyropheophorbide-a methyl ester (PPME), a second generation hotosensitizer, was investigated in various solvents. Absorption and fluorescence spectra showed that the photosensitizer was under a monomeric form in ethanol as well as in dimyristoyl-L-α-phosphatidylcholine liposomes while it was strongly aggregated in phosphate buffer. A quantitative determination of reactive oxygen species production by PPME in these solvents has been undertaken by electron spin resonance associated with spin trapping technique and absorption spectroscopy. In phosphate buffer, both electron spin resonance and absorption measurements led to the conclusion that singlet oxygen production was not detectable while hydroxyl radical production was very weak. In liposomes and ethanol, singlet oxygen and hydroxyl radical production increased highly; the singlet oxygen quantum yield was determined to be 0.2 in ethanol and 0.13 in liposomes. The hydroxyl radical production origin was also investigated. Singlet oxygen was formed from PPME triplet state deactivation in presence of oxygen. Indeed, the triplet state formation quantum yield of PPME was found to be about 0.23 in ethanol, 0.15 in liposomes (too small to be measured in PBS). [less ▲]

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See detailPhysical and mechanical properties of black locust (Robinia pseudoacacia) wood grown in Belgium
Pollet, Caroline; Verheyen, Cécile; Hebert, Jacques ULg et al

in Revue canadienne de recherche forestière (2012), 42(5), 831-840

The objective of this study was to characterize black locust (Robinia pseudoacacia L.) wood on the basis of its physical and mechanical properties. The results are compared with those reported in the ... [more ▼]

The objective of this study was to characterize black locust (Robinia pseudoacacia L.) wood on the basis of its physical and mechanical properties. The results are compared with those reported in the literature for English oak (Quercus robur L.), teak (Tectona grandis L. f.), and afzelia (Afzelia sp.), since black locust is likely to be used for the same purposes as the former species. The variations between sites, trees, and radial positions in the trunk were also studied. The physical and mechanical properties of black locust wood were evaluated on clear wood specimens taken from 27 trees distributed over five sites in Wallonia (Belgium) according to Belgian and French standards. Most of the black locust’s mechanical properties are higher than those of oak and teak. The black locust is classified as a “mid-heavy” (734 kg·m–3) and “half-hard” (5.22) wood type with very high resilience (17.2 J·cm–2), modulus of elasticity (15 700 MPa), and tensile strength in static bending (138 MPa). Its resilience is exceptional, higher than that of teak and afzelia, while its modulus of elasticity and bending strength, which surpass those of teak, are comparable with those of afzelia. Black locust shows high total volumetric shrinkage (16%), placing it in the “nervous” class, average tangential (8.8%) and radial shrinkage (5.5%) as well as average axial compressive (63 MPa) and splitting strength (17.8 N·mm–1). No technological incompatibilities would prevent the use of this wood for many value-added purposes (floor, deck, exterior woodwork, and furniture); however, significant shrinkage makes it necessary to condition the wood to its service moisture. [less ▲]

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See detailPhysical and numerical modeling of overbank flow with a groyne on the floodplain
Peltier, Yann ULg; Proust, S.; Bourdat, A. et al

in River Flow 2008: 4th Int. Conf. on Fluvial Hydraulics (2008)

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See detailPhysical and numerical modelling in low-head structures design
Dewals, Benjamin ULg; Archambeau, Pierre ULg; Rulot, François ULg et al

in Bung, Daniel; Pagliara, Stefano (Eds.) Proceedings of the International Workshop on Hydraulic Design of Low-Head Structures (2013, February)

Physical and numerical modelling may be combined within so-called composite or hybrid modelling. This enables to optimally take benefit of the respective strengths of each modelling approach, while ... [more ▼]

Physical and numerical modelling may be combined within so-called composite or hybrid modelling. This enables to optimally take benefit of the respective strengths of each modelling approach, while compensating for their specific drawbacks. Different types of composite modelling may be identified, such as embedding a detailed physical model within a broader scale numerical model, interconnecting different physical and numerical models focusing each on specific processes, or validating a numerical model from experimental data before exploiting the numerical model to generate more results than availa-ble from the experimental facility. Besides, specifically in more basic research, composite modelling may also be used to improve in-depth understanding of the relative importance of different processes which act simultaneously in the experimental test and may be artificially separated in numerical simulations. [less ▲]

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See detailPhysical and physiological impacts of different foam control strategies during a process involving hydrophobic substrate for the lipase production by Yarrowia lipolytica
Kar, Tambi ULg; Destain, Jacqueline ULg; Thonart, Philippe ULg et al

in Bioprocess and Biosystems Engineering (2012), 35(4), 483-492

The potentialities for the intensification of the process of lipase production by the yeast Yarrowia lipolytica on a renewable hydrophobic substrate (methyloleate) have been investigated. The key factor ... [more ▼]

The potentialities for the intensification of the process of lipase production by the yeast Yarrowia lipolytica on a renewable hydrophobic substrate (methyloleate) have been investigated. The key factor governing the lipase yield is the intensification of the oxygen transfer rate, considering the fact that Y. lipolytica is a strict aerobe. However, considering the nature of the substrate and the capacity for protein excretion and biosurfactant production of Y. lipolytica, intensification of oxygen transfer rate is accompanied by an excessive formation of foam. Two different foam control strategies have thus been implemented: a classical chemical foam control strategy (CFM) and a mechanical foam control (MFM) based on the Stirring As Foam Disruption (SAFD) principle. The second strategy allows foam control without any modifications of the physico-chemical properties of the broth. However, the MFM system design induced the formation of a persistent foam layer in the bioreactor. This phenomenon has led to the segregation of microbial cells between the foam phase and the liquid phase in the case of the bioreactors operated with MFM control, and induced a reduction at the level of the lipase yield. More interestingly, flow cytometry experiments have shown that residence time of microbial cells in the foam phase tends to induce a dimorphic transition which could potentially explain the reduction of lipase excretion. [less ▲]

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See detailPhysical and textural characteristics of hydrogenated low-erucic acid rapeseed oil and low-erucic acid rapeseed oil blends
Danthine, Sabine ULg; Deroanne, Claude ULg

in Journal of the American Oil Chemists' Society (2003), 80(2), 109-114

Low-erucic acid rapeseed oil (LERO) and hydrogenated low-erucic acid rapeseed oil (HLERO) were blended in binary systems. The blends were then studied for their physical properties such as solid fat ... [more ▼]

Low-erucic acid rapeseed oil (LERO) and hydrogenated low-erucic acid rapeseed oil (HLERO) were blended in binary systems. The blends were then studied for their physical properties such as solid fat content, melting curves by DSC, textural properties, and polymorphism. Phase behavior diagrams were constructed from the DSC and X-ray results, and isosolid diagrams were constructed from the NMR results. The mixture of HLERO and LERO displayed a monotectic behavior for all the storage time at 15degreesC. The aim of this work was to evaluate physical characteristics of binary blends of HLERO and nonhydrogenated LERO in order to use only LERO and hardened LERO in bakery shortenings. The mixture of 60% HLERO and 40% LERO is suitable to use as a plastic shortening, This blend is beta tending upon storage at 15degreesC. It could be used in pie crust applications. [less ▲]

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See detailPhysical characteristics of the back are not predictive of low back pain in healthy workers : a prospective study
Van Nieuwenhuyse, An; Crombez, Geert; Burdorf, Alex et al

in BMC Musculoskeletal Disorders (2009), 10(2), 1-9

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See detailPhysical Characterization Methods for Supplementary Cementitious Materials.
Arvaniti, Eleni; Juenger, Maria; Bernal, Susan et al

in Materials and Structures (2014)

The main supplementary cementitious materials (SCMs) that are used today are industrial by-products. In most cases the quality of these materials cannot be controlled during their production, resulting in ... [more ▼]

The main supplementary cementitious materials (SCMs) that are used today are industrial by-products. In most cases the quality of these materials cannot be controlled during their production, resulting in materials with varied characteristics. The adequate physical characterization of SCMs is important to better predict their performance and optimize their use in concretes production. There are standardized methods used to determine the particle characteristics for Portland cements that are usually adopted to characterize SCMs; however, these methods may not be as accurate when applied to SCMs. This paper is an overview of the techniques that are currently used for the determination of the density, particle size distribution, surface area and shape of SCMs. The main principles of each method are presented. The limitations that occur for the SCMs measurements are also discussed. This paper is an output from the work of the RILEM Technical Committee on Hydration and Microstructure of Concrete with Supplementary Cementitious Materials (TC-238-SCM). [less ▲]

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See detailThe physical chemistry of comets
Swings, Polydore ULg

in Popular Astronomy (1943), 51

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See detailPhysical constraints on color transformations
Manfroid, Jean ULg

in Astronomy and Astrophysics (1992), 260

Color-transformation procedures in photometry should ideally obey physical principles. A few of these rules, of particular interest in the study of reddened stars, of multiple stars, stellar clusters and ... [more ▼]

Color-transformation procedures in photometry should ideally obey physical principles. A few of these rules, of particular interest in the study of reddened stars, of multiple stars, stellar clusters and galaxies are discussed. Directions to minimize the transformation errors for these objects are given. [less ▲]

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See detailPhysical controls on the storage of methane in landfast sea ice
Zhou, Jiayun ULg; Tison, J.-L.; Carnat, G. et al

in The Cryosphere (2014), 8(3), 1019-1029

We report on methane (CH4) dynamics in landfast sea ice, brine and under-ice seawater at Barrow in 2009. The CH4 concentrations in under-ice water ranged between 25.9 and 116.4 nmol L-1sw, indicating a ... [more ▼]

We report on methane (CH4) dynamics in landfast sea ice, brine and under-ice seawater at Barrow in 2009. The CH4 concentrations in under-ice water ranged between 25.9 and 116.4 nmol L-1sw, indicating a supersaturation of 700 to 3100 % relative to the atmosphere. In comparison, the CH4 concentrations in sea ice, ranged between 3.4 and 17.2 nmol L-1ice, and the deduced CH4 concentrations in brine, between 13.2 and 677.7 nmol L-1brine. We investigated on the processes explaining the difference in CH4 concentrations between sea ice, brine and the under-ice water, and suggest that biological controls on the storage of CH4 in ice was minor in comparison to the physical controls. Two physical processes regulated the storage of CH4 in our landfast ice samples: bubble formation within the ice and sea ice permeability. Gas bubble formation from solubility changes had favoured the accumulation of CH4 in the ice at the beginning of ice growth. CH4 retention in sea ice was then twice as efficient as that of salt; this also explains the overall higher CH4 concentrations in brine than in the under-ice water. As sea ice thickened, gas bubble formation became less efficient, CH4 was then mainly trapped in the dissolved state. The increase of sea ice permeability during ice melt marked the end of CH4 storage. [less ▲]

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See detailPhysical Education Stimulating a Healthy Lifestyle and Critical Sports Consumption in Belgium
De Martelaer, Kristine; Seghers, Jan; Cardon, Greet et al

in Chin, Ming-Kai; Edginton, Christopher (Eds.) Physical Education and Health Global Perspectives and Best Practice (2014)

In this chapter, the authors describe the situation and challenges of Physical Education (PE) in Flanders and Wallonia in order to encourage young people to adopt a healthy lifestyle and to become ... [more ▼]

In this chapter, the authors describe the situation and challenges of Physical Education (PE) in Flanders and Wallonia in order to encourage young people to adopt a healthy lifestyle and to become critical sports consumers. In school-age children, about one out of six has problems with obesity/overweight. Compared with earlier measurements there is a trend of increasing sedentary time per day and not enough physical activity (PA) to reach international norms. Girls can be definitely considered as a public at risk regarding the physical activity component of their healthy lifestyle. In recent years, the emphasis has shifted from motor- and/or physical-testing towards the development of a positive attitude towards physical activity and being socially engaged. The main concern of the course-specific final attainment levels is teaching how to deal with the current movement culture of games, sports, fitness, and daily activity. In both regions, it is expected that children are taught to transfer movement and personally-related competencies learned in PE to other contexts. Initiatives to develop and enhance links between PE and other opportunities to be physically active in the wider community are receiving more attention during the last few years, but the situation is still far from ideal. Because of the complex role of promoting a healthy lifestyle during PE and in the whole school, there is a need to educate teachers during their teacher training and lifelong education on how to provide relevant choices, satisfying the need for autonomy. [less ▲]

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See detailThe physical education teacher as a physical activity promoter : Current developments
Cloes, Marc ULg

Conference (2014, May 24)

The current society needs to fight against the growing of sedentary lifestyles among the population all around the world. The school environment is identified as a pillar of the multisectorial approach ... [more ▼]

The current society needs to fight against the growing of sedentary lifestyles among the population all around the world. The school environment is identified as a pillar of the multisectorial approach that should be implemented to avoid that children who born today do not live less longer than their parents. The presentation will focus on four topics: (1) The role of school in physical activity (PA) promotion; (2) The dimensions of PA at school; (3) The action that physical education (PE) teacher can play; (4) The role of PE teacher educators in the improvement of the PE adaptation to the current needs. For one child, there are several opportunities to be physically active at school but the part of the school in youth PA is not well documented. Since recently, the only strong evidence of the effectiveness of interventions aiming to promote PA in youth was identified in adolescents when school and family/community environments are combined. However, some reviews have now revealed that school-based PA interventions can be effective for improvements in BMI, motor performance, physical activity, knowledge … In order to design one PA promotion project at school, five dimensions should be considered: (1) Physical education; (2) Sport at school (links to the community); (3) Active transportation; (4) Life environment (recesses, spaces); (5) Physical activity in the classroom. All these dimensions should be supported by a strong school policy that considers PA as a key aspect for the youth development. It means that packages of school-based strategies need to be developed. Nevertheless, PE seems to be a central aspect emphasizing the key role of the PE teachers who should become the PA promoters in every school. Unfortunately, since few decades, PE is facing a worldwide crisis raising questions about its quality and focusing on the teaching process, the inadequate school-community co-ordination, the focus on competition performance sport and the lack of interest on basic human movement and needs. Three concepts are now influencing some changes: (1) The physical literacy; (2) The accountability, and; (3) The Quality Physical Education (QPE). This means that, in PE, a special emphasis should now be set on the acquisition by the youth of knowledge, skills and attitude that will make them physically educated persons for their whole life, with the purpose to reach concrete improvements and to respect students’ needs and motivational characteristics. PE teachers have to show what they are doing in the promotion of an active lifestyle, using sports like a tool for general aims and not as a final objective. On the field, this means that new contents and teaching strategies have to be developed. The involvement of the students and the implementation of their learning into the real life should become a priority. Collaboration with other actors of the educational community (other teachers, parents) or the local community (sport clubs, sport administrations, private sector …) should be developed. PE teachers have to take these new roles. To achieve such change, they need to be supported by the PE teacher educators who have to emphasize the new educating strategies, develop concrete material and resources, contribute to create communities of practice, provide evidence based data supporting the effectiveness of the new approaches. The presentation will propose systematic ‘give and go’ between theory and practice in order to connect researchers and physical education teachers, underlining that PE can only grow with such collaboration and development of a networking. [less ▲]

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See detailThe physical education teacher as a physical activity promoter
Cloes, Marc ULg

Conference (2013, October 25)

Nowadays, physical education is more and more focused on the development of an active lifestyle among the students who are supposed to become physically educated citizen throughout life. The presentation ... [more ▼]

Nowadays, physical education is more and more focused on the development of an active lifestyle among the students who are supposed to become physically educated citizen throughout life. The presentation is divided in six parts: AIESEP Statement on Sport Pedagogy; From sport educator to PA promoter: The (r)evolution of PE teachers; What about ‘Quality Physical Education’?; How to be a PA promoter?; PETE for PA promoters; Conclusions. [less ▲]

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See detailThe physical education teacher as a physical activity promoter: Current developments
Cloes, Marc ULg

Conference (2014, November 19)

The physical education teacher is considered as a cornerstone of the physical activity promotion in the schools. This presentation proposes answers to three questions: (1) Why to promote physical activity ... [more ▼]

The physical education teacher is considered as a cornerstone of the physical activity promotion in the schools. This presentation proposes answers to three questions: (1) Why to promote physical activity at school? (2) Why the PE teacher should play a central role? (3) How the PE teacher could play such role? In conclusion, it is important to remember that (1) PE teachers should become the cornerstones of the PA promotion at school; (2) They have to be involved in PE as well as in the other dimension of PA at school; (3) They have to collaborate (they are not alone), and; (4) Pre service and inservice PETE has to be adapted to show the way and change the mentalities [less ▲]

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See detailPhysical education teachers as physical activity promoters: Examples of initial/continuous preparation processes
Cloes, Marc ULg

Conference (2010, November)

Literature emphasizes the increasing prevalence of obesity. This phenomenon is related to growing health problems and to their cost for the society in terms of health expenses as well as lack of human ... [more ▼]

Literature emphasizes the increasing prevalence of obesity. This phenomenon is related to growing health problems and to their cost for the society in terms of health expenses as well as lack of human well-being. Sedentary lifestyle is systematically pointed out as one of the determining factors at the origin of this situation. WHO (2001) underlined the need of a multifactorial action while Pate et al. (2006) highlighted the school’s central role. Within the school, it seems that the physical education (PE) teacher represents the corner stone of any process aiming to promote physical activity (PA) (USDHHS, 1996; Tappe & Burgeson, 2004). Nevertheless, when determining if PE teachers are ready to be the expected PA promoters, it appears that, in Wallonia (as it could be the case in other countries), several data show that the answer is not really positive. It seems that PE teachers need some support in order to make youths physically active, and adopting a healthy lifestyle. In fact, proposing traditional lessons focusing on sport would not be sufficient to reach these objectives. In this way, PE teacher educators should have two priorities: (1) to clarify the PE teachers’ representations of PA and (2) to identify and share strategies aiming to define their potential actions on the field. The presentation illustrated four approaches that were experimented at the University of Liege in pre- and in-service PE teacher education. The major goal of the speech was to involve the participants by stimulating reflexibility and content development. Four questions have been in the centre of the activity: (1) What is physical Activity? (2) What must be done, finally? (3) How to deal with arguments against practice? (4) What could do PE teachers to promote an active lifestyle? Each question was discussed through distinct approaches that could be used by the participants in their own practice. [less ▲]

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See detailPhysical education teachers’ perception of pupils’ motivation.
Cloes, Marc ULg; Ledent, Maryse; Delfosse, Catherine et al

in Chin, M. K.; Hensley, M. D.; Liu, Y. K. (Eds.) Innovation and application of physical education and sports science in the new millennium - An Asia-Pacific Perspective (2001)

Motivational aspects play a particularly important role in teaching. They are considered a powerful mediator between teacher action and teaching effects. Pupils’ motivation towards school and physical ... [more ▼]

Motivational aspects play a particularly important role in teaching. They are considered a powerful mediator between teacher action and teaching effects. Pupils’ motivation towards school and physical education has already been analysed from the pupils’ point of view (Piéron, Ledent, Almond, Airstone and Newsburry, 1996). On another side, its perception by teachers is less documented. This study focused on the identification by PE teachers of pupils’ behaviours indicating that they were motivated or not. Moreover, perception of reasons related to lack of motivation in pupils was also investigated. Twenty-nine teachers fulfilled a questionnaire during an inservice preparation seminar. Their answers were analysed and inductively classified in categories. Thirteen categories of criteria showing the presence or lack of motivation were identified. Motivation was predominantly perceived by (1) the quality of the working climate (16.8%); (2) the intend to be involved in the PE lesson (14%); (3) positive reactions towards the subject matter (11.2%) and an efficient time management (11.2%). The most important categories related to lack of motivation were: (1) absences or excuses (20.2%); (2) low time on task (14%) and (3) negative reactions towards the subject matter (14%). Concerning origins of the lack of motivation, teachers emphasised: (1) the large differences between pupils (13.7%); the lack of sport culture of youth (10.5%) and (3) the negative pupils’ attitude towards school. [less ▲]

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See detailPhysical Fitness and Mitochondrial Respiratory Capacity in Horse Skeletal Muscle
Votion, Dominique ULg; Gnaiger, Erich; Lemieux, Hélène et al

in PLoS ONE (2012), 7(4), 1-12

We applied high-resolution respirometry and multiple substrate-uncoupler-inhibitor titration protocols to study mitochondrial physiology in small (1.0–2.5 mg) permeabilized muscle fibres sampled from ... [more ▼]

We applied high-resolution respirometry and multiple substrate-uncoupler-inhibitor titration protocols to study mitochondrial physiology in small (1.0–2.5 mg) permeabilized muscle fibres sampled from triceps brachii of healthy horses. The present investigation on horse skeletal muscle has tested the methodology used to study mitochondrial function in muscle microbiopsies by high-resolution respirometry to define reference protocols for horses (from sampling procedure to data analysis). [less ▲]

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See detailPhysical forcing and physical/biochemical variability of the Mediterranean Sea: A review of unresolved issues and directions for future research
Malanotte-Rizzoli et al, Paula; Artale, V; Borzelli-Eusebi, G et al

in Ocean Science (2014), 10(3),

This paper is the outcome of a workshop held in Rome in November 2011 on the occasion of the 25th anniversary of the POEM (Physical Oceanography of the Eastern Mediterranean) program. In the workshop ... [more ▼]

This paper is the outcome of a workshop held in Rome in November 2011 on the occasion of the 25th anniversary of the POEM (Physical Oceanography of the Eastern Mediterranean) program. In the workshop discussions, a number of unresolved issues were identified for the physical and biogeochemical properties of the Mediterranean Sea as a whole, i.e., comprising the Western and Eastern sub-basins. Over the successive two years, the related ideas were discussed among the group of scientists who participated in the workshop and who have contributed to the writing of this paper. Three major topics were identified, each of them being the object of a section divided into a number of different sub-sections, each addressing a specific physical, chemical or biological issue: 1. Assessment of basin-wide physical/biochemical properties, of their variability and interactions. 2. Relative importance of external forcing functions (wind stress, heat/moisture fluxes, forcing through straits) vs. internal variability. 3. Shelf/deep sea interactions and exchanges of physical/biogeochemical properties and how they affect the sub-basin circulation and property distribution. Furthermore, a number of unresolved scientific/methodological issues were also identified and are reported in each sub-section after a short discussion of the present knowledge. They represent the collegial consensus of the scientists contributing to the paper. Naturally, the unresolved issues presented here constitute the choice of the authors and therefore they may not be exhaustive and/or complete. The overall goal is to stimulate a broader interdisciplinary discussion among the scientists of the Mediterranean oceanographic community, leading to enhanced collaborative efforts and exciting future discoveries [less ▲]

Detailed reference viewed: 11 (0 ULg)