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See detailDéfi climatique: l'état et le marché
Gautier, Axel ULg

Conference given outside the academic context (2016)

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See detailEcoNum, a research unit devoted to marine environment monitoring
Richir, Jonathan ULg; Batigny, Antoine; Georges, Nadège et al

Conference (2016, October 27)

The monitoring of coastal environments remains a research domain of great interest and concern. Coastal ecosystems are threatened by natural and human-induced stressors and are, as transitional ... [more ▼]

The monitoring of coastal environments remains a research domain of great interest and concern. Coastal ecosystems are threatened by natural and human-induced stressors and are, as transitional environments, particularly sensitive to disturbances. EcoNum first research thematic revolves around hermatypic corals, calcifying organisms, and their adaptation potentials to environmental changes including by using original and patented chemostats. The studied organisms are grown and maintained in artificial mesocosms that simulate environmental conditions of a natural system. This infrastructure allows to perform long-term experiments, giving time to organisms to adapt to the tested conditions (e.g., increased temperature or lowered pH). Longer-term studies have demonstrated that many organisms are more resistant to environmental stressors than previously observed on the short-term. EcoNum also studies coastal plankton abundance and diversity. Plankton is particularly sensitive to physicochemical changes of water bodies. The classification and the enumeration of planktonic organisms require specialized tools in order to analyse time series of multiple samples. EcoNum has developed a software for the semi-automatic classification of planktonic organisms called Zoo/PhytoImage. This software has been used to study a 10-year time series of coastal Mediterranean zooplankton samples. The concomitant analysis of environmental parameters registered at high frequency with specific statistical tools such as the R package pastecs allows to understand the processes governing the changes observed in plankton assemblages. The use and the development of statistical tools in R (e.g., Zoo/Phytoimage, pastecs) is a priority of EcoNum to favour open access knowledge and reproductive sciences. EcoNum research topics also focus on coastal ecotoxicology. Chemicals, including trace elements, remain contaminants of concern, mainly in coastal environments that are the final sink of inland pollution sources. The chemical integrity of coastal ecosystems thus has to be accurately monitored. The partitioning of chemicals between their dissolved, particulate and sedimentary phases does not provide information on their bioavailability. EcoNum thus monitors coastal waters using bioindicator species such as seagrasses, mussels or sand worms. A global map of the contamination of the Mediterranean by trace elements has been drawn using seagrasses has bioindicator species. EcoNum also studies trace element ecology and toxicology. For instance, it has demonstrated the toxicity of copper on the coral Seriatopora hystrix and it's symbiont's photosynthetic processes, or its bioaccumulation and basipetal translocation towards rhizomes in the seagrass Posidonia oceanica as reserve nutrient for subsequent leaf growth. Finally, coastal vegetated systems are potential carbon thinks (or sources) in the global carbon cycle. Therefore, EcoNum studies the primary productivity of seagrass meadows, from the individual to the community, with measuring techniques as diverse as PAM-fluorometry or biomass production determination. To conclude, EcoNum is a research unit devoted to marine environment monitoring. It develops research thematics on major coastal communities such as coral reefs, seagrass beds or plankton assemblages and studies their natural dynamics and the effects of stressors on their global functioning. [less ▲]

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See detailBollywood et les limites du soft power indien
Vlassis, Antonios ULg

in Telos (electronic journal) (2016)

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See detailCase report: Ovarian fibroma in a mare – Hormonal considerations
Ponthier, Jérôme ULg; Salciccia, Alexandra ULg; Parrilla Hernandez, Sonia ULg et al

in Reproduction in Domestic Animals (2016, October 27), 51(supplement 2), 132

This report shows that, as in humans, AMH as well as steroids productions are low in case of ovarian fibroma, thus preserving normal cyclicity.

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See detail6ème Cours de Mécanique Analytique II (2016-17), Bac3 phys, Master 1 Sc. Sp.
Surdej, Jean ULg

Learning material (2016)

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See detailLa vaisselle du Piano della Civita / Artena (Italie) : le témoignage du verre
Dienst, Simon ULg

Scientific conference (2016, October 27)

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See detailThe dynamics of market, credit and liquidity risk in the US corporate bond market
Heck, Stéphanie ULg

Doctoral thesis (2016)

Market, credit and liquidity constitute important risk factors in financial markets. Investors looking for optimal combinations of risk and return have to monitor their portfolios with regard to each of ... [more ▼]

Market, credit and liquidity constitute important risk factors in financial markets. Investors looking for optimal combinations of risk and return have to monitor their portfolios with regard to each of those factors. This work brings answers to some of the challenges presented by these three risk factors in the US corporate bond market. Market risk is the earliest and most widely acknowledged risk factor, affecting all financial securities. The risk that the issuer of the bond might go bankrupt introduces credit risk for corporate bonds. Finally, these securities are also characterized by a low trading frequency. Liquidity in this market has been severely affected by the recent global financial crisis as well as by the regulatory changes that followed the crisis. The first part of this dissertation studies the return premium investors require in compensation for undertaking credit risk. It is shown that distributional characteristics of individual assets and in particular the contribution of an asset’s return to the market portfolio’s skewness and kurtosis are important determinants of these premiums. The second part explores commonality in individual bond liquidity levels. It is shown that the pricing of liquidity in yield spreads is essentially due to this commonality. The final part of this dissertation designs a corporate bond market index based on the repeat-sales technique. The index adequately captures aggregate market dynamics and contributes to the explanation of the cross-section of individual corporate bond returns. [less ▲]

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See detailBounding surface plasticity model for natural clays
Ahayan, Sanae ULg; Yin, Zhen-Yu; Kotronis, Panagiotis et al

Conference (2016, October 26)

Natural soft clay exhibits a considerable degree of anisotropy as a result of its past sedimentation and consolidation history. It also tends to have significant inter-particle bonding, which affects its ... [more ▼]

Natural soft clay exhibits a considerable degree of anisotropy as a result of its past sedimentation and consolidation history. It also tends to have significant inter-particle bonding, which affects its mechanical behavior. The natural structure of in-situ soils makes their behavior different from that of a reconstituted material. In fact, most clays lose a proportion of their strength when remoulded. Various authors proposed anisotropic elastoplastic soil models allowing the yield surface to rotate with the stress history. These models have a “rotational hardening law" which relates the change of the inclination of the yield surface to the current soil state and to the increments of the plastic volumetric and/or shear strain, [Sekiguchi and Otha (1977)], [Hashiguchi and Chen (1998)], [Wheeller et al (2003)]… Other authors combine the plastic anisotropy with destructuration effects observed in soft sensitive soils by assuming that the size and /or the position of the center of the yield surface depends on the amount of the structural soil degradation. These models use an additional isotropic hardening law that relates the size and/or the position of the yield surface of the intact sample to that of the reconstituted one [Nova et al (2003)]. The previous models provide little or no flexibility when it comes to describe the change of the plastic modulus with the loading direction as they are unable to produce a smooth degradation of the stiffness, being single yield surface models. A way to improve this behavior is to introduce the “bounding surface plasticity” theory, initially developed by Dafalias [Dafalias and Herrmann 1986]. Unlike a single yield surface model, the bounding surface theory allows a smooth transition of stresses within and on the bounding surface. The mean feature of this concept is that the actual stress is mapped to the imaginary stress on the bounding surface. The distance between the real and imaginary stress, which is called the “ function distance ”, is used to specify the plastic modulus. This work presents a bounding surface plasticity model for natural and structured clays based on the critical state theory. A novel rotational hardening rule for clays is presented, and a hardening function distance is introduced to describe the evolution of the bounding surface. Validation of the model is provided by drained and undrained tests of Scottish and Finnish intact and reconstituted clays [Kastunnen 2008]. Finally, finite element simulations of a foundation considering the formulated constitutive law are presented. [less ▲]

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See detailCompetition between finite-size effects and dipole–dipole interactions in few-atom systems
Damanet, François ULg; Martin, John ULg

in Journal of Physics : B Atomic Molecular & Optical Physics (2016), 49

In this paper, we study the competition between finite-size effects (i.e. discernibility of particles) and dipole–dipole interactions in few-atom systems coupled to the electromagnetic field in vacuum. We ... [more ▼]

In this paper, we study the competition between finite-size effects (i.e. discernibility of particles) and dipole–dipole interactions in few-atom systems coupled to the electromagnetic field in vacuum. We consider two hallmarks of cooperative effects, superradiance and subradiance, and compute for each the rate of energy radiated by the atoms and the coherence of the atomic state during the time evolution. We adopt a statistical approach in order to extract the typical behaviour of the atomic dynamics and average over random atomic distributions in spherical containers with prescribed k0 R with k0 the radiation wavenumber and R the average interatomic distance. Our approach allows us to highlight the tradeoff between finite-size effects and dipole– dipole interactions in superradiance/subradiance. In particular, we show the existence of an optimal value of k0R for which the superradiant intensity and coherence pulses are the less affected by dephasing effects induced by dipole–dipole interactions and finite-size effects. [less ▲]

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See detailInterspecific variation of warning calls in piranhas: a comparative analysis
Melotte, Geoffrey ULg; Vigouroux, Régis; Michel, Christian ULg et al

in Scientific Reports (2016)

Fish sounds are known to be species-specific, possessing unique temporal and spectral features. We have recorded and compared sounds in eight piranha species to evaluate the potential role of acoustic ... [more ▼]

Fish sounds are known to be species-specific, possessing unique temporal and spectral features. We have recorded and compared sounds in eight piranha species to evaluate the potential role of acoustic communication as a driving force in clade diversification. All piranha species showed the same kind of sound-producing mechanism: sonic muscles originate on vertebrae and attach to a tendon surrounding the bladder ventrally. Contractions of the sound-producing muscles force swimbladder vibration and dictate the fundamental frequency. It results the calling features of the eight piranha species logically share many common characteristics. In all the species, the calls are harmonic sounds composed of multiple continuous cycles. However, the sounds of Serrasalmus elongatus (higher number of cycles and high fundamental frequency) and S. manueli (long cycle periods and low fundamental frequency) are clearly distinguishable from the other species. The sonic mechanism being largely conserved throughout piranha evolution, acoustic communication can hardly be considered as the main driving force in the diversification process. However, sounds of some species are clearly distinguishable despite the short space for variations supporting the need for specific communication. Behavioural studies are needed to clearly understand the eventual role of the calls during spawning events. [less ▲]

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See detailRedrawing as Reframing. Graphiation, Quotation and Comics History
Crucifix, Benoît ULg

Scientific conference (2016, October 26)

Coining the concept of ‘graphiation’ to theorize the narrative functions of drawing in comics, Philippe Marion’s Traces en cases has become a seminal text in comics studies due to its further ... [more ▼]

Coining the concept of ‘graphiation’ to theorize the narrative functions of drawing in comics, Philippe Marion’s Traces en cases has become a seminal text in comics studies due to its further theorizations by, among, others, Jan Baetens, Jared Gardner, and Simon Grennan. This presentation hopes to make an original contribution to these discussions by focusing on the issue of quotation and redrawing in graphic narratives, practices that interrogate how the ‘graphic trace’ relates to the drawing subject. I will compare and contrast two culture-specific terms: ‘case mémorable’ in the context of Franco-Belgian comics and ‘swiping’ in the context of American comic books. Both terms point at how comics images circulate across the borders of their original formats trough different technicalities of reproduction (mechanical or hand-crafted) that split them from both their immediate and larger contexts. While these terms are frequently used by creators, fans and readers alike, they have gained no currency in comics theory. My attempt, however, is not to argue for their inclusion within that vocabulary but rather to understand how these terms articulate, within the comics world, debates about quotation and redrawing. I will briefly retrace the genealogy of these terms in fan discourses to finally show how two contemporary cartoonists–Charles Burns and Olivier Josso Hamel–revisit them in ways that foreground the cultural and narrative stakes of reusing ‘old’ comics. Comparing these two terms will shed light on distinct conceptions of copying, originality and quotation, hopefully providing fresh perspectives on the theory of graphiation [less ▲]

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See detailEffect of rotational hardening rule on the behavior of clayey soils
Ahayan, Sanae ULg; Kotronis, Panagiotis; Collin, Frédéric ULg et al

Scientific conference (2016, October 26)

Induced anisotropy is a constitutive feature of clays that can be numerically introduced through a proper "Rotational Hardening Rule" allowing the rotation of the yield and the potential plastic surfaces ... [more ▼]

Induced anisotropy is a constitutive feature of clays that can be numerically introduced through a proper "Rotational Hardening Rule" allowing the rotation of the yield and the potential plastic surfaces in the stress space. In this presentation, rotational hardening rule of yield surface for clays are first reviewed. Then, two typical rotational hardening rules are selected and compared through simulating drained triaxial tests of two Finnish clays. Furthermore, finite element simulations of a strip rigid footing considering different rotational hardening rules together with the case of isotropic yield surface without rotation are carried out in order to study the consequences of the isotropy assumption and the influence of the rotational hardening rule on the behavior of shallow foundation. [less ▲]

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See detailIn-utero coxsackievirus B4 infection of the mouse thymus
Jaïdane, Hela; Halouani, Aymen; Jmii, H. et al

in Clinical & Experimental Immunology (2016), Sous presse

Type B coxsackievirus (CV-B) infections are involved frequently in the triggering of several autoimmune diseases such as myocarditis, dilated cardiomyopathy, pericarditis, pancreatitis, type 1 diabetes ... [more ▼]

Type B coxsackievirus (CV-B) infections are involved frequently in the triggering of several autoimmune diseases such as myocarditis, dilated cardiomyopathy, pericarditis, pancreatitis, type 1 diabetes, encephalitis, thyroiditis or Sjo€gren’s syndrome. Serological and virological evidence suggests that maternal infections during pregnancy can play a role in the appearance of these diseases in offspring. The current study aims to explore the effect of an in-utero CV-B infection on the fetal thymus, the central site for programming immunological self-tolerance. In this perspective, female Swiss albino mice were inoculated intraperitoneally or orally with the diabetogenic CV-B4 E2 strain at gestational days 10 or 17. Offspring were killed at different post-inoculation times, and their thymuses were analysed for evidence of infection and alterations in thymic T cell subsets. In-utero CV-B infection of the thymus was demonstrated during the course of vertical transmission, as attested by viral RNA and infectious virus detection in most analysed samples. No histopathological changes were evident. Thymic T cells were not depleted, despite being positive for viral RNA. As evidenced by flow cytometry analysis, CV-B infection of the fetal thymus induced significant changes of thymic T cell populations, particularly with maternal inoculation at gestational day 10. Altogether, these findings suggest that CV-B infection of the fetal thymus may play an important role in the genesis of autoimmune diseases. [less ▲]

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See detailA near-infrared interferometric survey of debris-disc stars. V. PIONIER search for variability
Ertel, S.; Defrere, Denis ULg; Absil, Olivier ULg et al

in Astronomy and Astrophysics (2016), 595

Context. Extended circumstellar emission has been detected within a few 100 milli-arcsec around ≳10% of nearby main sequence stars using near-infrared interferometry. Follow-up observations using other ... [more ▼]

Context. Extended circumstellar emission has been detected within a few 100 milli-arcsec around ≳10% of nearby main sequence stars using near-infrared interferometry. Follow-up observations using other techniques, should they yield similar results or non-detections, can provide strong constraints on the origin of the emission. They can also reveal the variability of the phenomenon. Aims: We aim to demonstrate the persistence of the phenomenon over the timescale of a few years and to search for variability of our previously detected excesses. Methods: Using Very Large Telescope Interferometer (VLTI)/Precision Integrated Optics Near Infrared ExpeRiment (PIONIER) in H band we have carried out multi-epoch observations of the stars for which a near-infrared excess was previously detected using the same observation technique and instrument. The detection rates and distribution of the excesses from our original survey and the follow-up observations are compared statistically. A search for variability of the excesses in our time series is carried out based on the level of the broadband excesses. Results: In 12 of 16 follow-up observations, an excess is re-detected with a significance of > 2σ, and in 7 of 16 follow-up observations significant excess (> 3σ) is re-detected. We statistically demonstrate with very high confidence that the phenomenon persists for the majority of the systems. We also present the first detection of potential variability in two sources. Conclusions: We conclude that the phenomenon responsible for the excesses persists over the timescale of a few years for the majority of the systems. However, we also find that variability intrinsic to a target can cause it to have no significant excess at the time of a specific observation. [less ▲]

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See detail1-D shallow water model for industrial practice: Application to the River Romanche
Goffin, Louis ULg; Dewals, Benjamin ULg; Erpicum, Sébastien ULg et al

Scientific conference (2016, October 25)

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See detailPlace de l'élevage bovin dans l'économie rurale des Peuls du Nord Bénin
Chabi Toko, Roukayath ULg

Doctoral thesis (2016)

Fulani belong to a socio-cultural group mainly encountered in West Africa and usually raises cattle. In Benin, Fulani are predominantly met in the two eastern departments of the North where they lead an ... [more ▼]

Fulani belong to a socio-cultural group mainly encountered in West Africa and usually raises cattle. In Benin, Fulani are predominantly met in the two eastern departments of the North where they lead an agro-pastoral way of life. In addition to livestock farming, they cultivate food and cash crops such as cotton. However, they hold majority of the country’s cattle population. The present study was initiated to understand to what extend cattle contributes to their rural economy. A stratified random sample of 150 heads of Fulani households, cattle farmers have been identified in Malanville, Banikoara and Kalalé districts in Borgou and Alibori departments. The criteria considered were: the agro-ecological zone, cattle population and the importance of Fulani population. The first series of surveys enable to characterize Fulani’s cattle farming system and their family farms. Among the 50 heads of households of Kalalé district (which has the more important Fulani community), 16 were selected and it is within their households that the study continued. The households selected were that with a better milk production. Surveys were then carried out during two years, both in dry season and rainy season to describe the Fulani’s household’s economy. The cattle stock composition showed a gender imbalance, with a preponderance of female stock (76%). Cattle herds which average size were 66 animals are made of 86% of Borgou breed. The herds have low breeding performance characterized by a high rate of calf mortality (10%) and low reproductive parameters: calving and fertility rates were 64%. The purchase of fodder in dry season, which concerns 17% of farmers, is a practice encountered in agroecological zones that register light rainfall. Fulani’s large households enable them to have enough family labor to carry out both livestock and agriculture activities. The land is mostly inherited and the average size for a household is about 10.5 ha. All Fulani households are crops producers of which majority (80%) is consumed. A significant part (45%) of them grow an average of 3.3 ha of cotton. In Fulani family farms, cattle represent 52% of the household livestock size; there is also small ruminants and poultry. This cattle permit to majority (76%) of Fulani households to have milk for sale. But milk is managed to favor household consumption and ensure the herd's reproduction. The organization around milk involves male and female. The profits from milk and cheese are distributed among the women of the household at various levels. Although the low (7%) cattle market rate, it contributes significantly (68%) to the household’s monetary income in rainy season and represents the second source (27%) of revenue in dry season. The 20% of food products are mainly sold in dry season and thus contribute to the majority (64%) of income sources. However, when rains started late and the delayed payment of cotton fees, the majority of Fulani households’ cash income in the rainy season, came from cotton (64%) and food products (23%). The growing involvement of Fulani cattle herders of northern Benin on the foodstuffs market and in cotton will lead to two types of farms with opposed production targets (those that will favor livestock and others agriculture). Fulani are a target population that should receive a little more support from authorities because enable them to value their resources would ensure availability and accessibility of food and pastoral products and contribute to the improvement of country’s agricultural production. [less ▲]

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See detailSpecific interests in Autism with versus without speech onset delay : the importance of perceptually versus thematically organized interests
Chiodo, Liliane ULg; Eusèbe, Sandrine; Majerus, Steve ULg et al

Poster (2016, October 25)

To explore whether autistic adults with versus without speech delay also differ in the perceptual vs thematic nature of their specific interests.

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See detailLes impacts socio-économiques des indications géographiques
Fassotte, Bérénice ULg; Aucuit, Natacha; Parmentier, Isabelle et al

Conference given outside the academic context (2016)

Monter un dossier en vue d’obtenir un label européen AOP ou IGP peut s’avérer fastidieux et long : cela implique un consensus entre producteurs, le cahier des charges comprend un volet technique mais ... [more ▼]

Monter un dossier en vue d’obtenir un label européen AOP ou IGP peut s’avérer fastidieux et long : cela implique un consensus entre producteurs, le cahier des charges comprend un volet technique mais aussi un volet socio-historique, et les étapes de la procédure s’étendent sur de nombreux mois. Les producteurs sont donc en droit de se demander quelles pourront être les retombées de cette labélisation. Cette présentation illustre les impacts socio-économiques des indications géographiques et démontre l’intérêt de ces labels pour les producteurs. [less ▲]

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