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See detailTowards a better understanding of time-lapse electrical resistivity properties associated to organic contaminants and bioremediation processes in the subsurface
Caterina, David ULg

Doctoral thesis (2014)

Management of contaminated sites represents a major problem for our society. Geophysical methods arise progressively as non-conventional techniques that should allow decreasing the uncertainty linked to ... [more ▼]

Management of contaminated sites represents a major problem for our society. Geophysical methods arise progressively as non-conventional techniques that should allow decreasing the uncertainty linked to the local nature of punctual drilling/sampling measurements classically used to identify, characterize and monitor such sites. However, the use of geophysics for this purpose is relatively recent and still requires an improvement of geophysical imaging and a better understanding of the impact of contaminants and remediation processes on measured properties to be fully effective. The main objective of this thesis was thus to improve our knowledge on these two aspects. In order to assess the reliability of geophysical imaging, and electrical resistivity tomography (ERT) in particular, we first compare quantitatively different image appraisal indicators. The latter are developed to detect artefacts, estimate depth of investigation, address parameters resolution and appraise ERT-derived geometry. Numerical benchmarks are created representing different geological situations in terms of heterogeneity and scale. On the basis of this comparison, we propose a methodology and guidelines to appraise both qualitatively and quantitatively field ERT images. We show the successful applications on real data coming from the contaminated sites we investigated. It notably allows us to exclude from our interpretation zones of the electrical images that are not considered as sufficiently reliable. To enhance electrical imaging, we investigate three different approaches to incorporate prior information into the ERT inverse problem, namely reference model, structural constraint and regularized geostatistical inversion that we notably apply on real data coming from two contaminated sites. The results are benchmarked against the standard smoothness constraint inversion. Results with real data show that adding prior information in the inversion process always lead to a modification of the solution at least in zones of low sensitivity (allowing notably to better image contaminant plumes at depth). However, the choice of the constraint to apply is highly dependent on the type and amount of information available. Therefore, we provide guidelines that should help the practitioner to include their prior information directly into the inversion process through an appropriate way. To understand the temporal geoelectrical signature of organic contaminants and bioremediation processes, we monitor a site contaminated with hydrocarbons and subjected to stimulated bioremediation. We first show that the most contaminated areas above the groundwater table level are associated to very low resistivities. We then show that during biostimulation (promoting aerobic degradation) and natural attenuation, observed resistivity variations (up to 140%) are mostly located in the saturated zone of the contaminated area. They follow a seasonal trend suggesting a temperature dependence not observed in an uncontaminated zone of the site. However, in the contaminated area, changes largely exceed the expected variations due only to the temperature. We therefore investigate systematically different hypotheses that may explain such changes. Among those hypotheses, we show that microbial activity is a factor that may potentially influence the electrical signature of a contaminated soil and may contribute to the observed resistivity changes. In order to further study the electrical response associated to bacterial activity during bioremediation processes, we monitor a tank experiment that contains soils contaminated with hydrocarbons subjected first to biostimulation and then to bioaugmentation (with an inoculum of Rhodococcus erythropolis T902.1). Whereas no particular electrical signature is observed during the biostimulation phase, we observe a correlation between the evolution of bulk resistivity changes and the specific oil-degrading flora after bioaugmentation that cannot be attributed to fluid resistivity changes. This suggests a direct impact of microbial growth/activity on electrical properties through the modification of surface and/or local electrolytic conduction mechanisms. These latter results open up new perspectives for future experiments that should involve spectral induced polarization measurements allowing a better discrimination between the two conduction mechanisms. [less ▲]

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See detailCompeting One-Way Essential Complements : the Forgotten Side of the Net Neutrality Story
Broos, Sébastien ULg; Gautier, Axel ULg

Conference (2014, July 11)

We examine the incentives of an internet service provider (ISP) to break net neutrality by excluding internet applications competing with its own products, a typical example being the exclusion of VoIP ... [more ▼]

We examine the incentives of an internet service provider (ISP) to break net neutrality by excluding internet applications competing with its own products, a typical example being the exclusion of VoIP applications by a telecom company offering internet and voice services. We show that exclusion is not a concern when the ISP is a monopoly because it can extract the additional surplus created by the application through price rebalancing. By contrast, when ISP’s compete, in an attempt to differentiate, only one ISP will offer the app. Applying a no-exclusion rule in this case can lead to monopoly. [less ▲]

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See detailEffect of lignocellulose related compounds on microalgae growth and product biosynthesis: a review
Miazek, Krystian ULg; Remacle, Claire ULg; Richel, Aurore ULg et al

in Energies (2014), 7(2014), 4446-4481

Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates ... [more ▼]

Microalgae contain valuable compounds that can be harnessed for industrial applications. Lignocellulose biomass is a plant material containing in abundance organic substances such as carbohydrates, phenolics, organic acids and other secondary compounds. As growth of microalgae on organic substances was confirmed during heterotrophic and mixotrophic cultivation, lignocellulose derived compounds can become a feedstock to cultivate microalgae and produce target compounds. In this review, different treatment methods to hydrolyse lignocellulose into organic substrates are presented first. Secondly, the effect of lignocellulosic hydrolysates, organic substances typically present in lignocellulosic hydrolysates, as well as minor co-products, on growth and accumulation of target compounds in microalgae cultures is described. Finally, the possibilities of using lignocellulose hydrolysates as a common feedstock for microalgae cultures are evaluated. [less ▲]

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See detailA formulation on the special Euclidean group for dynamic analysis of multibody systems
Sonneville, Valentin ULg; Bruls, Olivier ULg

in Journal of Computational and Nonlinear Dynamics (2014), 9(4), 041002

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See detailDiversity of Bacterial Communities in a Profile of a Winter Wheat Field: Known and Unknown Members
Stroobants, Aurore ULg; Degrune, Florine ULg; Olivier, Claire et al

in Microbial Ecology (2014)

In soils, bacteria are very abundant and diverse. They are involved in various agro-ecosystem processes such as the nitrogen cycle, organic matter degradation, and soil formation. Yet, little is known ... [more ▼]

In soils, bacteria are very abundant and diverse. They are involved in various agro-ecosystem processes such as the nitrogen cycle, organic matter degradation, and soil formation. Yet, little is known about the distribution and composition of bacterial communities through the soil profile, particularly in agricultural soils, as most studies have focused only on topsoils or forest and grassland soils. In the present work, we have used bar-coded pyrosequencing analysis of the V3 region of the 16S rRNA gene to analyze bacterial diversity in a profile (depths 10, 25, and 45 cm) of a well-characterized field of winter wheat. Taxonomic assignment was carried out with the Ribosomal Database Project (RDP) Classifier program with three bootstrap scores: a main run at 0.80, a confirmation run at 0.99, and a run at 0 to gain information on the unknown bacteria. Our results show that biomass and bacterial quantity and diversity decreased greatly with depth. Depth also had an impact, in terms of relative sequence abundance, on 81 % of the most represented taxonomic ranks, notably the ranks Proteobacteria, Bacteroidetes, Actinobacteridae, and Acidobacteria. Bacterial community composition differed more strongly between the topsoil (10 and 25 cm) and subsoil (45 cm) than between levels in the topsoil, mainly because of shifts in the carbon, nitrogen, and potassium contents. The subsoil also contained more unknown bacteria, 53.96 % on the average, than did the topsoil, with 42.06 % at 10 cm and 45.59 % at 25 cm. Most of these unknown bacteria seem to belong to Deltaproteobacteria, Actinobacteria, Rhizobiales, and Acidobacteria. [less ▲]

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See detail(Wrong) representations of physical activity, from definition to recommandations
Cloes, Marc ULg

Conference (2014, July 10)

Faisant partie intégrante de notre vie quotidienne, l’activité physique et la sédentarité constituent deux notions qui s’opposent dans la conception d’un style de vie sain. Les recherches actuelles ... [more ▼]

Faisant partie intégrante de notre vie quotidienne, l’activité physique et la sédentarité constituent deux notions qui s’opposent dans la conception d’un style de vie sain. Les recherches actuelles montrent que chacune d’elles devrait faire l’objet d’une attention particulière. Toutefois, qu’ils fassent partie du grand public ou appartiennent à des professions liées à la santé, il apparait que les individus ne construisent pas toujours des représentations adéquates à propos des bonnes habitudes de vie. Dans la perspective d’influencer favorablement la culture des citoyens en matière d’activité physique, il s’avère donc nécessaire de rappeler régulièrement les informations clés qui devraient être retenues et appliquées dans la vie de tous les jours. Afin d’illustrer la manière avec laquelle les représentations peuvent constituer le fil rouge d’un processus amenant les gens à adopter un style de vie physiquement actif et peu sédentaire, nous passerons brièvement en revue la définition de l’activité physique, l’identification de ses effets et les recommandations proposées actuellement par les agences de santé publique. Nous utiliserons différentes approches ludiques originales, susceptibles de faire vivre aux participants des expériences visant à stimuler le traitement des informations et à privilégier leur rétention. Au niveau de la définition de l’activité physique, l’objectif consistera à faire ressortir les différentes dimensions de l’activité physique. Puisque les recherches les plus récentes en soulignent l’incidence de plus en plus marquée, nous insisterons également sur la distinction entre les différents niveaux d’intensité de la pratique. Ensuite, une classification des effets bénéfiques de l’activité physique sera proposée avant une révision des recommandations internationales. Les modalités de présentation originales qui seront mises en place stimuleront la prise de conscience de certaines mauvaises représentations, courantes dans le public. La dernière partie de l’exposé consistera à illustrer les contre-arguments à opposer à ceux qui ne sont pas encore convaincus qu’ils pourraient bouger davantage. [less ▲]

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See detailSelf broadening coefficients and improved line intensities for the n7 band of C2H4 near 10.5 mm, and impact on ethylene retrievals from Jungfraujoch solar spectra
Vander Auwera, Jean; Fayt, André; Tudorie, Marcela et al

Poster (2014, July 10)

Ethylene (ethene, C2H4) is a tropospheric pollutant on the Earth, also present as a by-product of methane photochemistry in the atmosphere of outer solar system bodies. Remote sensing of ethylene in the ... [more ▼]

Ethylene (ethene, C2H4) is a tropospheric pollutant on the Earth, also present as a by-product of methane photochemistry in the atmosphere of outer solar system bodies. Remote sensing of ethylene in the infrared range relies on the 10 mm region. This spectral range corresponds to the excitation of 7 modes of vibration of 12C2H4, 4 of which being infrared active (see Fig. 1 of [1]). The corresponding n10, n7, n4 and n12 bands are located near 826, 949, 1026 and 1442 cm-1, respectively [1]. Among these, the n7 band is the strongest, indeed used for remote sensing measurements of ethylene. Relying on high-resolution Fourier transform infrared (FTIR) spectra recorded in Brussels, the present work involved extensive measurements of individual line intensities and self broadening coefficients for the n7 band of 12C2H4. Compared to the corresponding information available in the latest edition of the HITRAN spectroscopic database (HITRAN 2012 [2]), the measured line intensities were found to be higher by about 10 % for high J lines in the P branch and lower by about 5 % for high J lines of the R branch, varying between these two limits roughly linearly with the line positions. Test calculations performed in this work indicated that these discrepancies could result from the relative values of the transition moments of the n10, n7 and n12 bands used when the information provided in HITRAN was generated (the transition moment of the n4 band was set to zero). The measured self broadening coefficients exhibit a dependence on both J and Ka, which was modeled empirically. The spectroscopic information for ethylene available in HITRAN 2012 was modified to match the present observations. The impact of these modifications on retrievals of atmospheric ethylene was then evaluated via FTIR retrievals in the 949.0 – 952.0 cm-1 microwindow, from a subset of ground-based high-resolution FTIR solar spectra recorded at the Jungfraujoch station. The new line intensities were found to lead to a reduction of the measured total columns of ethylene by -4.1±0.1 %, compared to the use of HITRAN 2012. [less ▲]

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See detailOutils d’étude pour caractériser l’impact de l’ hydrodynamique sur la culture de cellules animales adhérentes cultivées sur microporteurs en bioréacteurs à cuve agitée
Collignon, Marie-Laure ULg

Conference (2014, July 10)

Cette présentation montre l'importance du choix des conditions d'agitation lors de la culture de cellules animales adhérentes sur microporteurs en bioréacteurs à cuve agitée. Elle montre des exemples d ... [more ▼]

Cette présentation montre l'importance du choix des conditions d'agitation lors de la culture de cellules animales adhérentes sur microporteurs en bioréacteurs à cuve agitée. Elle montre des exemples d'outils pour caractériser à l'échelle locale l'hydrodynamique au sein de ces bioréacteurs et une approche Euler-Lagrange qui a terme permettra de faire le lien entre l'hydrodynamique et la réponse cellulaire grâce à l'établissement de l'historique de conditions rencontrées localement par les cellules. [less ▲]

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See detailLiterature through Technology. Depicting the Future of the Book from Verne to Barjavel
Stienon, Valérie ULg

Conference (2014, July 10)

French futuristic novels tend to develop a wide range of representations regarding the book of the future as it is impacted by technical inventions, from the phone to the digital paradigm through ... [more ▼]

French futuristic novels tend to develop a wide range of representations regarding the book of the future as it is impacted by technical inventions, from the phone to the digital paradigm through photography and film: Albert Robida’s “phono-livre” (La Vie électrique, 1890), Octave Uzanne’s “storyographe” powered by electricity from the human body, Henri Allorge’s “bibliophone” (Le grand cataclysme, 1922), Léon Daudet’s “cinébiblat” and “cinélivre” (Le Napus, 1927), Maurice Renard’s telepathic book (Un homme chez les microbes, 1928) or even René Barjavel’s “télélecture” (Ravage, 1943) among others. It is well known that the historical antagonism between Science and the Humanities deeply influenced the disciplinary boundaries and the respective values of the two fields. But it also appears that such a disciplinary discussion does involve the issue of the material and tangible forms of the book considered as an object. Futuristic novels put a specific emphasis on the acoustic, visual and tactile avatars of the book within a sociocultural context characterized by the rise of Applied Sciences and media communication. Do these new media and formats compete with or complement to the former book patterns? Are such representations of the book as an audiovisual item some response to the predicted decline of the Humanities? Or are they rather a means of asserting the faith in a new forthcoming kind of literature? Although science may badly affect literature so as to produce an impoverishing mechanization of literary style (Jules Verne, Paris au XXe siècle, 1863), it also gives a valuable opportunity to create more ergonomic formats for a wider distribution and a more easily handheld book. Since the late 19th century until WWII, many futuristic novels propose to consider the book as it is located at the junction of Science and the Humanities rather than in their dichotomous opposition. Regarded as a specific leitmotiv, such a topic of technological and transmedia conversions of the book leads to reconsider the evolution of the identity paradigm of France as a “literary nation”. It also gives the opportunity to investigate the discrepancies and coincidences between the conjectural scope of these futuristic novels and the factual history of technological advances. [less ▲]

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See detailCommentaire sur l'étude: « Belgique-Maroc, 50 années de migration »
Martiniello, Marco ULg

Scientific conference (2014, July 10)

Detailed reference viewed: 14 (1 ULg)
See detailSupercritical CO2, impregnation to prepare drug-loaded implants: inpregantion of anti-inflammatory drugs into sutures
Champeau, Mathilde; Tassaing, Thierry; Thomassin, Jean-Michel ULg et al

Conference (2014, July 10)

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See detailSynthesis of degradable polyphosphoester copolymers for templating calcium carbonate drug delivery carriers
Ergül, Zeynep ULg; Debuigne, Antoine ULg; Calvignac, Brice et al

Conference (2014, July 09)

Degradable acid bearing polyphosphoester (PPE) copolymers were prepared by combination of organocatalyzed ring opening polymerization and click chemistry. Their solution behavior and ability to complex ... [more ▼]

Degradable acid bearing polyphosphoester (PPE) copolymers were prepared by combination of organocatalyzed ring opening polymerization and click chemistry. Their solution behavior and ability to complex calcium ions were studied as well as their capacity to template CaCO3 particles dedicated to drug delivery. [less ▲]

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See detailWhich links exist between depression, engagement in activities’ level and several psychological processes?
Wagener, Aurélie ULg; Blairy, Sylvie ULg

Poster (2014, July 09)

In Europe, depression affects 33.4 millions of people every year. According to the World Health Organization, depression will be the leading cause of disabilities in 2030. This highlights the need for ... [more ▼]

In Europe, depression affects 33.4 millions of people every year. According to the World Health Organization, depression will be the leading cause of disabilities in 2030. This highlights the need for available, effective and efficient treatments of this psychopathology. In order to offer such treatments, there is a need for a deep understanding of depression’s mechanisms. Depression is characterized by a decrease of the level of engagement in activities: for instance, depressed patients stay in bed, don’t see friends, don’t go out anymore and can be on sick leave for a long period of time. Reciprocally, this decrease maintains depressive symptoms. This link between depression and level of engagement in activities is well-established in the scientific literature. However, no study has, until yet, determined which psychological processes are mediators of this link. Therefore, this study’s aim is to determine these psychological processes. In order to reach this aim, 500 subjects, suffering from psychopathology or not, will fulfill a set of questionnaires. These questionnaires will assess mood (anxiety and depression), level of engagement in activities and five categories of psychological processes that have been selected from different theoretical models of depression (self-image, environmental satisfaction, negative repetitive thoughts, experiential avoidance and emotional regulation). Statistical analysis will be performed in order to confirm a LISREL model. Data collection is ongoing and results will be presented and discussed during the congress. [less ▲]

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See detailApproximation algorithms for multi-dimensional vector assignment problems
Crama, Yves ULg

Conference (2014, July 09)

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See detailApplication of multiple-point geostatistics on groundwater flow and transport in media with complex geological heterogeneity: lessons learnt and remaining challenges
Huysmans, Marijke; Dassargues, Alain ULg

in Proceedings (2014, July 09)

Multiple-point geostatistics has been increasingly applied on groundwater problems in the last ten years. Several case studies have been published indicating simulating realistic geological heterogeneity ... [more ▼]

Multiple-point geostatistics has been increasingly applied on groundwater problems in the last ten years. Several case studies have been published indicating simulating realistic geological heterogeneity using multiple-point geostatistics can significantly improve groundwater flow and solute transport predictions. There are however several remaining challenges when applying multiple-point geostatistics to groundwater problems often suffering from data scarcity. These challenges might be the reason why multiple-point has been used to a much lesser extent by practitioners than by researchers. This paper gives an overview of the current challenges and discusses new advancements to overcome them. The following questions will be discussed: How to obtain 3D training images? Can the representativity of the used training image be validated ? How sensitive are groundwater calculations to the selection of the training image? Is it worth incorporating fine scale geological heterogeneity in groundwater problems or are other features (boundary conditions, data uncertainty/quality, …) more important for improving predictions? How can multiple-point geostatistics be used without suffering from very long computation times for the numerical models? Is overparametrization of groundwater models an issue ? What are the practical obstacles to apply multiple-point geostatistics by groundwater practitioners? [less ▲]

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See detailLarge-scale stochastic optimization using non-stationary geostatistics for uncertainty assessment of groundwater flow and solute transport, in the framework of a near surface radioactive waste disposal
Rogiers, Bart; Laloy, E.; Gedeon, Matej et al

Poster (2014, July 09)

Uncertainty quantification is very much needed to support decision making related to e.g. environmental impact assessment for waste disposal sites. A probabilistic result provides a much stronger basis ... [more ▼]

Uncertainty quantification is very much needed to support decision making related to e.g. environmental impact assessment for waste disposal sites. A probabilistic result provides a much stronger basis for decision making compared to a single deterministic outcome. Accurate posterior exploration of high-dimensional and CPU-intensive models, which are often used for environmental impact assessment, is however a challenging task. To quantify the uncertainty associated with solute transport in the framework of a near surface radioactive waste disposal in Mol/Dessel, Belgium, we investigate combining the adaptive Metropolis (AM) McMC algorithm for updating the global model parameters, and adaptive spatial resampling (ASR) for updating of the spatially distributed model parameters, by block sampling. The forward model used is a groundwater flow model conditioned on borehole and direct push data, that accounts for non-stationary heterogeneity in hydraulic conductivity. The obtained flow solutions are used for solute transport simulations, and the results are compared with a different groundwater flow model parameterization, that makes use of homogeneous hydrogeological layers. Moreover, a number of simulations is performed to assess the effect of realistic dispersivity, which is derived from outcrop investigations. The obtained results indicate that the combination of AM and ASR using block sampling seems not to be very efficient for McMC sampling with the forward model used in this study. However, using the algorithm in optimization mode seems to work fine, and provides an alternate way for exploring the parameter space and the prediction uncertainty. [less ▲]

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See detailEuropean Renal Best Practice Guideline on kidney donor and recipient evaluation and perioperative care
Abramowicz, Daniel; Cochat, Pierre; Claas, Frans H.J et al

in Nephrology Dialysis Transplantation (2014)

Detailed reference viewed: 30 (6 ULg)
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See detailA longitudinal perspective of alcohol use among adolescents: the predictive role of peers and internalizing factors.
Schmits, Emilie ULg; Glowacz, Fabienne ULg; Quertemont, Etienne ULg

Poster (2014, July 09)

Alcohol is the most commonly used psychoactive substance among teenagers. Consumption is influenced by environmental factors and personal characteristics, events or experiences. High use can lead to ... [more ▼]

Alcohol is the most commonly used psychoactive substance among teenagers. Consumption is influenced by environmental factors and personal characteristics, events or experiences. High use can lead to substantial problems, especially after an early consumption. Detecting and preventing an increase of alcohol use among teenagers, through the identification of risk and protective factors, seems essential in terms of public health. This study aimed to examine the progression of use in young teenagers, to identify protective and risk factors of alcohol use (including peers and internalizing factors) and to specifically focus on the influence of social anxiety. A questionnaire was administered twice to 877 teenagers (49.94% female, M=15.61) with one year interval (T1 and T2). Sex, age, alcohol use, number of friends, social comparison, trait-anxiety, social anxiety and depression were assessed through validated scales. T-test for paired sample and hierarchical regressions were performed. During the follow-up year, the average alcohol use significantly increased. A positive social comparison at T1 significantly predicted alcohol use at T2. The more teenagers positively compared themselves to their friends and felt popular, the more they consume alcohol. A similar significant effect was demonstrated for depression. The more young people manifested depressive affects at T1, the more they used alcohol at T2. However, social anxiety significantly protected from this substance use. More social anxiety at T1 was associated with less alcohol consumption at T2. The number of friends and trait-anxiety at T1 did not significantly influence alcohol use at T2. A positive social comparison and depressive affects could be considered as risk factors, whereas social anxiety could be defined as protective factor. At this developmental period, young people suffering from social anxiety symptoms subsequently use less alcohol, maybe due to the lack of contact with this substance usually socially consumed, whereas more popular and integrated teenagers are more at risk. The present results challenge the tension-reduction model according to which alcohol is consumed to reduce anxious affects and to facilitate social relationships. However, results suggest that alcohol might be used to reduce unpleasant depressive affects. [less ▲]

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See detailThe consumption of pornography and sexuality during adolescence : between exploratory behaviour and risks of deviant behaviour
Glowacz, Fabienne ULg; Puglia, Rosa ULg

Conference (2014, July 09)

Pornographic consumption or exposure to sexually explicit media (SEM) during adolescence raises many questions, in particular concerning its incidence on the level of a teenager's psychosexual development ... [more ▼]

Pornographic consumption or exposure to sexually explicit media (SEM) during adolescence raises many questions, in particular concerning its incidence on the level of a teenager's psychosexual development and sexual behaviour. Adolescence is a stage of identity formation, characterized by the adoption of risk taking and exploratory behaviours, of which the consumption of pornography is part. Whereas some studies noticed an impact of the exposure to sexually explicit media on the level of the subject's psychosexual development, attitudes towards sexuality and sexual behaviour, other studies do not highlight any significant links between the voluntary or involuntary exposure to pornography and risk taking sexual behaviours. Two researches will be presented to deal with this question. The first study, relating to a sample of 319 teenagers aged between 15 to 18 (52% boys), shows that 85% of the subjects have already seen pornographic material, the average age a child first views pornography being between 10 and 14. Our results indicate that the forms of exposure to SEM as well as the representations of pornography and the impact of pornographic material on their sexuality are different depending on the subject's gender. Our second study, relating to a sample of 47 juvenile sexual offenders, will make it possible to consider the forms of consumption of these young people and the possible links between their sexual offence and the consumption of pornography. [less ▲]

Detailed reference viewed: 35 (7 ULg)