References of "Scientific congresses and symposiums"
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See detailRelation entre fatigue et travail chez des patients atteints de sclérose en plaques
DELRUE, Gaël ULg; Blavier, Adelaïde ULg; Hennen, Julie et al

Poster (2014, December 15)

Fatigue is one of the most frequent symptom in multiple sclerosis patients (MS patients). We showed significant correlations between fatigue levels and difficulties encountered by our patients at work ... [more ▼]

Fatigue is one of the most frequent symptom in multiple sclerosis patients (MS patients). We showed significant correlations between fatigue levels and difficulties encountered by our patients at work evaluated through a specific questionnaire we already validated . This complaint must be carefully managed by professionnals in order to help the patients cope with it in the best way for maintaining work situation. [less ▲]

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See detailPerception du bien-être chez les étudiants de l’Université de Liège
Cloes, Marc ULg; Etienne, Anne-Marie ULg; Maslah, Olfa et al

Conference (2014, December 15)

This study is focused on the analysis of the wellness perception of a representative sample of students of the University of Liege. Findings confirm those of the literature as males at students who ... [more ▼]

This study is focused on the analysis of the wellness perception of a representative sample of students of the University of Liege. Findings confirm those of the literature as males at students who consider to be physically active have higher scores of wellness. The study reveals also that students who are still leaving with their parents have higher scores of wellness. [less ▲]

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See detailLiquidity patterns on the US corporate bond market
Heck, Stéphanie ULg; Margaritis, Dimitri; Muller, Aline ULg

Conference (2014, December 13)

Liquidity commonality exists and empirical evidence (e.g. Lin et al., 2011) indicates that exposure to this common liquidity factor is priced in the cross-section of corporate bonds. The existence of ... [more ▼]

Liquidity commonality exists and empirical evidence (e.g. Lin et al., 2011) indicates that exposure to this common liquidity factor is priced in the cross-section of corporate bonds. The existence of commonality implies that part of a bond’s illiquidity is left as idiosyncratic. In this paper, we study how illiquidity components explain the cross-section of bond yields and how this relationship varies over time and across bond categories. We use a factor decomposition to break down total illiquidity into a common and an idiosyncratic component and analyze how yields relate differentially to each of these two components. We find that a bond’s idiosyncratic illiquidity is important, which might reflect informational asymmetries compounded by the lack of diversification in the institutional investors’ portfolios. Moreover, the relation between illiquidity and yield spreads appears to be negative during the recent crisis period. [less ▲]

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See detailMarty and the 4th Logical Investigation: What is the disagreement really about?
Seron, Denis ULg

Conference (2014, December 13)

Detailed reference viewed: 44 (1 ULg)
Peer Reviewed
See detailBelowground Chemical Ecology: The Case of Wireworms
Barsics, Fanny ULg; Delory, Benjamin ULg; Delaplace, Pierre ULg et al

Conference (2014, December 13)

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See detailDetection of rRNA synthesis sites within reptilian nucleoli
Bartholomé, Odile ULg; Thiry, Marc ULg; Franck, Claire

Poster (2014, December 13)

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See detailFirst monitoring results of three straw bale buildings in Belgium
Evrard, Arnaud; Dubois, Samuel ULg; Louis, Arnaud et al

Conference (2014, December 13)

Straw bale use in buildings may be an interesting way to decrease our energy needs and our impact on environment. The present paper describes an experimental set up to monitor three straw bale buildings ... [more ▼]

Straw bale use in buildings may be an interesting way to decrease our energy needs and our impact on environment. The present paper describes an experimental set up to monitor three straw bale buildings recently built in Belgium. For each building, results on temperature and relative humidity, inside and outside, are analyzed, as well as internal evolution of temperature and humidity distribution in the walls. The first building is an office building where two finishing are compared. Measurements also provide additional data on CO2 levels and electric consumption. The two other buildings are dwellings where live one single family. In the first one, a wall in the bedroom and a retaining wall are analyzed. In the second one, a wall in the bedroom and a wall in the bathroom are analyzed. Their hygrothermal behavior is discussed based on simulation results obtained with WUFI Pro and WUFI Plus software. The criterion for the validation of wall behavior is based on water content distribution through the walls. The paper confirms the great potential of this type of building technology and helps to identify how to assess and validate their effective hygrothermal behavior. [less ▲]

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See detailTuta absoluta (Lepidoptera: Gelechiidae) ability to localize and develop on wild and cultivated solanaceous plant species
Bawin, Thomas ULg; Dujeu, David ULg; Fagan, Maud ULg et al

Conference (2014, December 13)

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little ... [more ▼]

The tomato leafminer, Tuta absoluta (Lepidoptera: Gelechiidae), is a widespread invasive species damaging economically important cultivated solanaceous crop plants, including tomatoes and potatoes. Little is known about the ability of this microlepidoptera to encounter and develop on alternative wild and agricultural plant species. These plants could provide refuges and have to be identified for more efficient integrated management strategies. In the present study, we assessed the ability of T. absoluta to develop on wild (Solanum nigrum, Atropa belladonna, Datura stramonium) and cultivated (Solanum tuberosum) solanaceous plant species under laboratory conditions. Fitness tests were performed in Petri dishes by isolating single individuals with excised leaf from one of the host plants. We found that Solanum species allowed higher larval survivability and shorter development time (from egg to adult emergency) compared to the other plants. Two choice behavioral assays performed in flying tunnels (S. tuberosum versus another plant) revealed that adult distribution and female oviposition did not differ between Solanum species, which were preferred to the other tested plants. These results appeared to be consistent with survival rates and development times. Because larval survivability depends on the female’s oviposition choice, the hypothesis that host plant choice is influenced by plant volatile organic compounds has to be tested. It can be concluded that Solanum species remain the more suitable hosts for T. absoluta development among the tested plants. Other plant species could be opportunistically colonized with little incidence but care should be taken in these results as genetic variability in insects and plants, as well as plant physiological state, might have an impact on the pest survivabilty. [less ▲]

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See detailNew technologies in conservation: monitoring African wildlife with UAS
Linchant, Julie ULg; Semeki, Jean; Lejeune, Philippe ULg et al

Conference (2014, December 13)

In the vast protected areas of Africa, traditional wildlife surveys performed by plane or foot are logistically difficult to implement due to the lack of means and appropriate materials. Moreover, the ... [more ▼]

In the vast protected areas of Africa, traditional wildlife surveys performed by plane or foot are logistically difficult to implement due to the lack of means and appropriate materials. Moreover, the possibilities of encountering poachers in the field pose a serious risk to the monitoring teams. Over the last decade, civilian UAS (Unmanned Aerial Systems) boomed in natural resource monitoring. One of the biggest challenges of the UAS is to replace traditional wildlife censuses for the application of wildlife conservation. Parameters have to be approached in a different way than before. We performed test flights in the open savannah of the Garamba National Park during the wet season using the Falcon Unmanned UAS. Both photos (Sony Nex7, 24Mp) and videos, including thermal infrared videos (Tamarisk 640x480), have been used. Flight altitude ranged from 50 to 200m and pictures showed that animals can be effectively detected at 100m. We spotted elephants, hippopotamus and buffaloes as well as other smaller species such as hartebeests, kobs and warthogs. Thermal videos gave medium quality results during the day due to the heat but performed well during the night. The limited range and endurance of the UAS suggest a rethink of the usual census protocols. We therefore tested new flight plans in a rosette shape to take advantage of the higher points in the park, with transects having the length of the maximal range. Twelve transects of 10km can be covered in half a day with pictures covering a 15.6km² area. Human activities could also be detected. Pictures showed areas burned by poachers and the thermal infrared camera allows the detection of fires from a high altitude. Future developments need to be investigated such as automatic detection to review the huge amount of data collected and statistical methods must be adapted to those challenging situations. [less ▲]

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See detailBelgien- und Deutschlandbilder als Spiegel der ostbelgischen Nachkriegsgesellschaft
Brüll, Christoph ULg

Conference (2014, December 13)

Detailed reference viewed: 9 (0 ULg)
Peer Reviewed
See detailGenetic structure of fragmented southern populations of African Cape Buffalo (Syncerus caffer caffer) based on microsatellite analysis
Smitz, Nathalie ULg; Cornélis, Daniel; Chardonnet, Philippe et al

Poster (2014, December 12)

Detailed reference viewed: 9 (1 ULg)
See detailPolyplex based on polycarbonate polymers for an efficient delivery of HDAC5 and HDAC7 siRNA
Frère, Antoine ULg; Evrard, Brigitte ULg; Mespouille, Laetitia et al

Conference (2014, December 12)

Detailed reference viewed: 5 (0 ULg)
Peer Reviewed
See detailThe cerato-mandibular ligament: an innovation for sound production and feeding in damselfishes (Pomacentridae).
Olivier, Damien ULg; Frederich, Bruno ULg; Spanopoulos-Zarco, Milton et al

Conference (2014, December 12)

The success of a taxonomic group can be promoted by a key character that allows the group to interact with its environment in a different way and to potentially occupy new niches. The Pomacentridae ... [more ▼]

The success of a taxonomic group can be promoted by a key character that allows the group to interact with its environment in a different way and to potentially occupy new niches. The Pomacentridae possess a synapomorphic trait, the cerato-mandibular (c-md) ligament, which joins the hyoid bar to the inner part of the lower jaw. It has previously been shown that this ligament is a key trait in communication in damselfishes because it enables them to slam the oral jaws shut causing teeth collision and sound production. This specific behavior of mouth closing could, however, also be used for other tasks, such as feeding. Many territorial damselfishes are referred to as farmers, due to their ability to manage algal crops on which they feed. This study hypothesizes that the c-md ligament provides an advantage for grazing filamentous algae, and should thus be considered a key trait for farming behavior. The kinematic patterns associated with sound production and biting filamentous algae or attached animal prey are all based on the same mechanism and are associated with a slam of the oral jaws. We observed that transection of the c-md ligaments makes the fish unable to perform such actions. This study shows that the c-md ligament is a key trait both for sound production and for grazing activities in damselfishes. The buccal jaw slam enables the fish to perform accurate strikes on small filamentous algae. This kind of bite probably plays a major role in farming activity and allows grazing damselfishes to occupy distinct niches, possibly increasing their competitive evolutionary success. [less ▲]

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See detailAnalphabétisme secondaire, raison cynique et la culture pour tous.
Hamers, Jérémy ULg

Conference (2014, December 12)

Detailed reference viewed: 24 (2 ULg)
Peer Reviewed
See detailSpatial variation in the concentrations of mercury and persistent organic pollutants in free-ranging bottlenose dolphins (Tursiops truncatus) from South Florida.
Damseaux, France; Kiszka, Jeremy; Heithaus et al

Poster (2014, December 12)

The bottlenose dolphin (Tursiops truncatus) is an abundant apex predator found in nearshore waters of South Florida, especially in the Lower Florida Keys (Key West) and the coastal waters of Everglades ... [more ▼]

The bottlenose dolphin (Tursiops truncatus) is an abundant apex predator found in nearshore waters of South Florida, especially in the Lower Florida Keys (Key West) and the coastal waters of Everglades National Park (ENP). The objective of this study was to assess variation in contamination levels of total mercury (T-Hg) and persistent organic pollutants (NDL-PCBs, PBDEs, DDT, HCH, HCB, PCDD/Fs and DL-PCBs) in bottlenose dolphins found offshore of the densely populated Key West (n = 27) and from undeveloped ENP (n = 20). [less ▲]

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See detailOpen Access, dream or reality for scholars: The ULg experience
Thirion, Paul ULg

Conference (2014, December 12)

Since the “serial price crisis”, no institution in the world has been able anymore to provide to scholars with the scientific literature they need. Although it was the first reason why the scientific ... [more ▼]

Since the “serial price crisis”, no institution in the world has been able anymore to provide to scholars with the scientific literature they need. Although it was the first reason why the scientific community developed Open Access initiatives, it’s absolutely not the only one. Nowadays, the awareness has become so large that many research players have put OA on the agenda (NIH, WHO, H2020, Wellcome Trust, FRS-FNRS…). The two main existing complementary ways will be described (Green and Gold) and Fools’ Gold will be denounced (unfair gold, hybrid journals, predatory journals). The University of Liege is one of the world leaders in OA with Green and Gold initiatives. What benefits can scholars expect from OA as authors and as readers on the basis of that experience? [less ▲]

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Peer Reviewed
See detailA gammaherpesvirus infection protects against allergic asthma.
Machiels, Bénédicte ULg; Dourcy, Mickael ULg; Sabatel, Catherine ULg et al

Poster (2014, December 12)

The “hygiene hypothesis” proposes that the augmentation of allergic diseases in developed countries could be linked to a reduced exposure to infections during childhood. Surprisingly, the potential ... [more ▼]

The “hygiene hypothesis” proposes that the augmentation of allergic diseases in developed countries could be linked to a reduced exposure to infections during childhood. Surprisingly, the potential protective role of herpesvirus infections against allergy development has never been addressed directly. In this study, we used the Murid herpesvirus 4 (MuHV-4) to study the impact of a persistent gammaherpesvirus infection on the development of House Dust Mites (HDM)-induced allergic asthma. Our results revealed that MuHV-4 infection affects both the sensitization and the challenging phases of HDM-induced airway allergy. In particular, we highlighted that MuHV-4 infection strongly impacts the lung innate immune response. Indeed, while the dendritic cells remained competent to uptake antigens and to migrate to the draining lymph nodes, MuHV-4 infection impaired their ability to trigger HDM sensitization. In the future, these results could allow us to develop strategies to prevent the development of TH2-skewed responses against respiratory allergens. [less ▲]

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See detailSymptômes neurologiques du bord latéral du pied et de la cheville
WANG, François-Charles ULg

Conference (2014, December 12)

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See detailShedding light on two unstudied species of Lepilemur in Northwest Madagascar
Wilmet, Leslie ULg; Beudels-Jamar, Roseline C.; Schwitzer, Christoph et al

Poster (2014, December 12)

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See detailSeasonal sampling and stable isotopes use to delineate seagrass phytodetritus macrofauna trophic ecology: baseline variation or actual diet change?
Remy, François ULg; Mascart, Thibaud ULg; Dauby, Patrick ULg et al

Conference (2014, December 12)

In Mediterranean exported seagrass macrophytodetritus accumulations, a diverse (more than 130 species) and abundant (up to 4900 id.m-2) macrofauna assemblage is found alongside meiofauna, microalgae ... [more ▼]

In Mediterranean exported seagrass macrophytodetritus accumulations, a diverse (more than 130 species) and abundant (up to 4900 id.m-2) macrofauna assemblage is found alongside meiofauna, microalgae, fungi and bacteria. Macrophytodetritus are mainly composed of poorly digestible yet highly colonized material: the dead leaves of the very productive (300 to 2000 g dry wt m-2 yr-1) endemic seagrass Posidonia oceanica. A key role may be played by macrofauna, and more particularly by litter vagile macroinvertebrates (invertebrates > 500µm), in the degradation, enrichment and carbon transfer from P. oceanica to coastal food webs. Indeed, results of gut content observations of the most abundant species show that even if only a few of these species ingest a large proportion of P.oceanica dead leaves fragments, most of the others ingest a small but non-negligible part, suggesting a potential role of the whole community in the mechanical fragmentation of the dead leaves. Mediterranean exported macrophytodetritus accumulations are very dynamic habitats with very variable food availability, quality, and composition. Such an inconstant habitat may result in drastic modifications of the invertebrate community but also of its trophic structure and ecology. To test this hypothesis of influence of pulsed availability, quality and composition of food sources on the vagile macrofauna diet, we took seasonal samples in Calvi Bay (Corsica, 8°45’E; 42°35’N), at two sites between August 2011 and May 2012. Gut content observations and C/N/S stable isotope analysis of bulk tissues were conducted on both the macrofauna and their potential food sources. Significant seasonal and spatial differences of ingestion patterns of the most abundant species were emphasised as were differences of isotopic signatures. “SIAR” Bayesian mixing model and “SIBER” package were used to analyse isotopic data and determine if these differences were due to actual diet modifications or only to baselines isotopic composition variations. [less ▲]

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See detailStable isotope ratios reveal trophic niche partitioning among hermit crabs from tropical polyspecific seagrass meadows
Michel, Loïc ULg; Frederich, Bruno ULg; Lavitra, Thierry et al

Poster (2014, December 12)

Polyspecific seagrass meadows are ubiquitous features of tropical coastal zones. These ecosystems are of critical ecological importance, and provide a wide range of socio-economical services to local ... [more ▼]

Polyspecific seagrass meadows are ubiquitous features of tropical coastal zones. These ecosystems are of critical ecological importance, and provide a wide range of socio-economical services to local populations. Meadows however undergo multiple threats linked to human activities (increased nutrient input, overfishing, invertebrate overharvesting, etc.). It is currently hard to assess how seagrass meadows could respond to anthropogenic impacts due to poor knowledge of their functional ecology. In an effort to unravel trophic interactions ruling the food webs associated to seagrass beds of the Toliara Great Reef (SW Madagascar), we studied resource segregation between two common Diogenidae hermit crabs (Dardanus scutellatus and Ciliopagurus tricolor) using stable isotope ratios. Interspecific differences were noted in isotopic composition of carbon (δ13C = -12.22 ± 1.73 ‰ for D. scutellatus, δ13C = -14.55 ± 0.73 ‰ for C. tricolor), nitrogen (δ15N = 4.73 ± 0.53 ‰ for D. scutellatus, δ15N = 5.20 ± 0.61 ‰ for C. tricolor) and sulfur (δ34S = 14.08 ± 2.32 ‰ for D. scutellatus, δ34S = 16.73 ± 1.49 ‰ for C. tricolor), suggesting that the two species do not feed on the same items. In addition, SIBER (Stable Isotope Bayesian Ellipses in R) modeling based on C and N data clearly showed that no overlap was present in the core isotopic niches of the two species. It also indicated that the isotopic niche of D. scutellatus was greater than the one of C. tricolor, implying that the former feeds on a greater number of items than the latter. While hermit crabs are generally considered as omnivorous species, this study highlighted differences in the foraging ecology of D. scutellatus and C. tricolor. These differences could help to limit competition for food between these two species, and facilitate their coexistence in Malagasy seagrass beds. [less ▲]

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See detailUmbilical hernia under local anaesthesia: tips and tricks
DETRY, Olivier ULg

Conference (2014, December 12)

Despite many studies confirming the feasibility and the interest of local anaesthesia for umbilical repair, its use is not generalized amongst the abdominal surgeons. The advantages of local anaesthesia ... [more ▼]

Despite many studies confirming the feasibility and the interest of local anaesthesia for umbilical repair, its use is not generalized amongst the abdominal surgeons. The advantages of local anaesthesia are indeed clear, including reduced costs, reduced hospital stay and reduced post operative pain. The success of the procedure depends on the skills and the motivation of the surgeon, of the nursing teams, and of the patient him/herself. The Mayo repair is ideally performed under local anaesthesia, but should be proposed to patients suffering from limited umbilical hernia with small defects. Prosthetic repairs might also be proposed under local anaesthesia, but large defects with rectus diastasis might require a full Rives/Stoppa repair in which local anaesthesia could not be sufficient. In obese patients, laparoscopic repair might be beneficial despite higher cost and longer hospital stay. Practically local anaesthesia requires some patience and quiet in the operative room. Operators should be aware that the action of local anaesthesia is delayed after injection. Local anaesthetics should be buffered and at body temperature at time of injection. Local anaesthetics containing Adrenalin allow longer pain control, with limitation of bleeding and less toxicity. Large and brutal movements should be avoided. Ligature and section of parts of greater omentum are feasible under local anaesthesia without patient discomfort. Tension free repair should be favoured, and during Mayo repair, the only painful part of the repair is often the closure of the defect with the different stiches. The surgical and anaesthetic techniques for umbilical hernia repair should be tailored to the specific characteristics of the umbilical hernia and of the patient. There is no method of choice that might fit for every patient. [less ▲]

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See detailSound production in piranhas and relatives: preliminary results
Melotte, Geoffrey ULg; Michel, Christian ULg; Parmentier, Eric ULg

Poster (2014, December 12)

Acoustic communication plays an important role in the life of many teleost species where it is mainly involved in agonistic and/or courtship behaviour(s). Despite the large number of species in the family ... [more ▼]

Acoustic communication plays an important role in the life of many teleost species where it is mainly involved in agonistic and/or courtship behaviour(s). Despite the large number of species in the family Serrasalmidae (92 species), sound production has been described only in some of them, particularly in the genera Serrasalmus and Pygocentrus. The aim of this study is to investigate the sound producing abilities of different Serrasalmidae species and to understand the corresponding mechanisms. Two herbivorous species of Serrasalmidae, Piaractus brachypomus and Metynnis lippincottianus, produce sounds composed of a single pulse. The mechanism involved in these species is not yet understood. In contrast, the calls emitted by several species of Serrasalmus and Pygocentrus are harmonic sounds composed of several pulses without inter-pulse interval. Their mechanism results from the forced vibration of the swimbladder following the contraction of sonic muscles that are attached to tendons surrounding ventrally the bladder. Another species, Pygopristis denticulata, is able to produce two types of sounds. The first sound consists of several pulses with irregular pulse period and is likely produced by a sonic muscle inserting on the skull and on the rostral part of the swimbladder. The second sound is multi-pulsed and, contrary to all other sounds described here, possesses a high dominant frequency suggesting a mechanism that does not involve the swimbladder and that remains to be determined. According to these results, Serrasalmidae seems to contain many species able to produce sounds by means of different mechanisms. [less ▲]

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See detailColonization of a new habitat by copepods: An in situ experiment
Mascart, Thibaud ULg; Lepoint, Gilles ULg; Biondo, Renzo ULg et al

Conference (2014, December 12)

Colonization of new habitats by a biological community is conspicuous and this dynamic process is one of the architectural forces of the biogeographical distribution we know today. Within the meiofauna ... [more ▼]

Colonization of new habitats by a biological community is conspicuous and this dynamic process is one of the architectural forces of the biogeographical distribution we know today. Within the meiofauna (<1mm), copepods (Crustacea) have successfully adapted to nearly every ecosystem and heir colonization power of permanent habitats is therefore well-established. However, few studies tackled the colonization of new naturally occurring provisional habitats, which are of ecological interest since they are rich in organic material, structurally complex and devoted of native fauna. Hence, the present study investigated the copepod colonization of provisional macrophytodetritus (mainly composed of senescent leaves and drift macroalgae) accumulated on bare sand patches inside a Mediterranean Posidonia oceanica seagrass meadow. General motive of colonization such as food and shelter are well-defined. However, little is known regarding the mode of the colonization and source pool of the associated colonists. Here, an in situ experiment was deployed in order to understand the mode of copepod’s colonization to fauna deprived macrophytodetritus. The objectives were: (1) assessing the adjacent colonist’s source pool (i.e. sediment, water column or P. oceanica canopy), (2) investigating the speed of settlement and (3) quantifying the species composition of the colonizing copepods. In summary: (1) species from every source pool actively colonized the macrophytodetritus through the water column and through the sediment-macrophytodetritus interface. (2) The initial settlement occurred within the first 24 hours. (3) The species composition showed to be different than the source’s composition. After 24h, the composition was similar to 45% of the P. oceanica, 28% of the water column and 25% of the sediments. After 96h, the composition was similar to 24% of the P. oceanica, 13% of the water column and 10% of the sediments. Indicating an evolution towards a macrophytodetritus copepod specific community composed of a mixture of the adjacent habitats first colonizers. [less ▲]

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See detailA morphospace for the marine angelfishes (Pomacanthidae): patterns of diversity
Frederich, Bruno ULg

Poster (2014, December 12)

The Pomacanthidae (marine angelfishes) is an iconic reef fish family of about 88 species. They have a circum-global distribution on tropical to warm-temperate reefs. Marine angelfishes occupy a diverse ... [more ▼]

The Pomacanthidae (marine angelfishes) is an iconic reef fish family of about 88 species. They have a circum-global distribution on tropical to warm-temperate reefs. Marine angelfishes occupy a diverse range of trophic niches, ranging from spongivory and algivory to zooplanktivory. Previous morpho-functional analysis of this family mainly focused on the head region and gut morphology in a limited number of species. However a morphological study including a large sample of angelfish representatives is currently lacking. Here, I explore the diversity of body morphology in this reef fish group. I collected x-ray images of 228 museum specimens from 71 species and I used landmark-based geometric morphometrics to quantify the overall body shape variation within this family. In a test for interspecific allometry, the linear regression of shape variables onto size (LogTL; TL = total length) was significant (P < 0.001). However, the percentage of explained variance in this model (23%) showed no strong relation between size and body shape. Main shape variation across species was explored using a principal component analysis on shape variables. The two main axes (PC1 and PC2) explained 74% of the total variance of the dataset. Pomacanthus spp., which mainly feed on fixed invertebrates (sponges and tunicates), have deep body with high and angular cephalic profile (lowest values along PC1). Conversely, the zooplanktivorous Genicanthus spp., those have a more pelagic lifestyle, show a slender body with shorter anal fin (highest values along PC1). The pigmy angelfishes from the genus Centropyge, which group different diets (omnivory or algivory), show a more robust and rectangular body shape (high scores along PC2). This work provides the row data for future studies dealing with the mode of phenotypic diversification of Pomacanthidae during evolution. [less ▲]

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See detailCo-evolution of the parasitic fungi Pneumocystis and their Muridae rodent hosts in Southeast Asia
Latinne, Alice ULg; Bezé, François; Morand, Serge et al

Conference (2014, December 12)

Pneumocystis species are opportunistic and airborne-transmitted fungi that infect the lungs of numerous mammalian species. These highly diversified fungi are characterized by strong host specificity ... [more ▼]

Pneumocystis species are opportunistic and airborne-transmitted fungi that infect the lungs of numerous mammalian species. These highly diversified fungi are characterized by strong host specificity, probably associated with co-speciation. In this study, we investigate the Pneumocystis genetic diversity and infection rate in Muridae rodents of Southeast Asia in relation to environmental habitats. A total of 445 wild rodents belonging to 18 Southeast Asian Muridae species were tested for the presence of Pneumocystis in their lungs through PCR amplification of two Pneumocystis mitochondrial genes (mtLSU rRNA and mtSSU rRNA). Pneumocystis DNA was detected in 215 (48.3%) out of these 445 rodents. Eight highly divergent Pneumocystis lineages were retrieved in our phylogenetic tree. Three of these lineages correspond to the described species Pneumocystis murina (infecting Mus species), P. carinii (infecting Rattus species) and P. wakefieldiae (also infecting Rattus species). Three individuals belonging to Rattus norvegicus were found co-infected by both P. carinii and P. wakefieldiae. The five remaining lineages may correspond to several new undescribed Pneumocystis species and infect the lungs of Cannomys (lineage 1), Bandicota (lineage 2), Berylmys (lineage 3), Rattus (lineage 4) and Maxomys, Niviventer and Leopoldamys (lineage 5) Muridae genera. The congruence between phylogenies of Pneumocystis and their rodent hosts has been tested using co-phylogenetic analyses and the number of inferred co-speciation events is significantly greater than expected by chance. Rodent species, age and sex have no influence on the Pneumocystis infection rate among Muridae rodents but individuals trapped close to human settlements in patchy habitat were more likely infected by Pneumocystis parasites. [less ▲]

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See detailNegations in Late Egyptian: the general trends. A functional and typological perspective
Winand, Jean ULg

Conference (2014, December 12)

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See detailMaintaining the coexistence of forest species of different shade tolerances with close-to-nature forestry
Ligot, Gauthier ULg; Philippe, Balandier

Conference (2014, December 12)

Continuous-cover forestry has the goal of relying on natural regeneration, and maintaining irregular stand structure and tree species mixture. However, maintaining mixture of species with different shade ... [more ▼]

Continuous-cover forestry has the goal of relying on natural regeneration, and maintaining irregular stand structure and tree species mixture. However, maintaining mixture of species with different shade tolerances appears arduous with such a silvicultural system. Successfully managing irregular and mixed forests, relying on natural processes, requires a strong knowledge of the ecology of natural regeneration. In theory, regeneration dynamics depends upon the amount of transmitted radiation: shade-tolerant species dominate the regeneration under closed canopies whereas less shade-tolerant species dominate the regeneration under partially open canopies. Nevertheless, it explains hardly the difficulties faced by forest managers to maintain the coexistence of species of different shade tolerances. The purpose of this research is to define light requirements of two species with contrasting shade tolerances (Fagus sylvatica L. and Quercus petraea (Matt.) Liebl.) and, next, determining how understory light can be controlled by forest managers. We find that, contrary to our expectations, the shade-tolerant species outgrow the less shade-tolerant species in all light conditions. We next examine the effects of canopy structure and composition on understory light availability with a model of light interception by heterogeneous canopies. Various silvicultural treatments are tested in order to provide favorable understory light conditions for natural regeneration. The results underline that creating favorable understory light conditions for natural regeneration can be achieved with various regeneration treatments. However, the adequate reduction of stand density depends upon the chosen silvicultural strategies. The outcomes of this study highlight that the control of understory light can be insufficient to maintain the coexistence of species of contrasting shade tolerance, and provide guidelines for the management of understory light in heterogeneous forests. [less ▲]

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See detailImpact of goldfish on terrestrial and aquatic microhabitat use in the palmate newt
Darnet, Elodie; Winandy, Laurane ULg; Denoël, Mathieu ULg

Poster (2014, December 12)

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See detailWhen microplastic is not microplastic: ingestion of artificial cellulose fibers by macrofauna living in seagrass macrophytodetritus
Collard, France ULg; Remy, François ULg; Gilbert, Bernard ULg et al

Poster (2014, December 12)

Vagile macroinvertebrates associated with Posidonia oceanica exported litter were sampled in August 2011, November 2011 and March 2012 in the Calvi Bay (Corsica), near the STARESO oceanographic station ... [more ▼]

Vagile macroinvertebrates associated with Posidonia oceanica exported litter were sampled in August 2011, November 2011 and March 2012 in the Calvi Bay (Corsica), near the STARESO oceanographic station. Contents of digestive tracts were analyzed and fibers of various sizes and colors were found. Fibers were found in 27.6% of the digestive tracts in the nine dominant species. No correlation was found between number of fibers and taxonomic or trophic level. There were no seasonal or spatial preferences and thus we hypothesize that the organisms ingest these fibers randomly throughout the year. Analyses performed with a Raman spectroscope showed that these fibers were composed of cellulose associated with a coloring agent following the fiber color. Red fibers were dyed with the Direct Red 28, blue fibers were dyed with Direct Blue 22. Analyses by a scanning electron microscope (SEM) showed that cellulose fibers had the particular morphology of artificial cellulose fibers called: viscose. Our SEM analyses were compared to literature. This comparison assessed that fibers found in digestive tracts were made of viscose. In a first approach, viscose fibers looked like microplastic fibers because of their color and shape. However, it appeared that these fibers were made of artificial cellulose which is very different than plastic in terms of impacts and fate in the organisms. This study highlights the importance of physico-chemical analyses such as Raman spectroscopy and SEM to certainly identify the composition of particles ingested by organisms. From an ecological point of view, the red coloring agent is known to be carcinogenic in mammals and fish. Consequently, this pollution could provoke an environmental problem for the P. oceanica litter vagile macrofauna. [less ▲]

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See detailRapid morphological change of barbels (Cyprinidae) after the dry-up of Sahara
Brahimi, Amina; Tarai, Nacer; Libois, Roland ULg

Poster (2014, December 12)

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See detailImpact of Climate Change on “Aphid - Natural Enemies” Relationship
Boullis, Antoine ULg; Oostrom, Marjolein; Francis, Frédéric ULg et al

Poster (2014, December 12)

While the effects of global atmospheric changes on vegetation and associated insect populations (bottom-up interactions) are increasingly studied, how these gases affect the interactions between insects ... [more ▼]

While the effects of global atmospheric changes on vegetation and associated insect populations (bottom-up interactions) are increasingly studied, how these gases affect the interactions between insects and their natural enemies (top-down interactions) is less clear. As the efficacy of natural enemies is governed largely by behavioral mechanisms, changes in their prey-seeking behavior or the behavior of insect prey defenses can change the dynamics of insect populations. The impact of increases in atmospheric carbon dioxide concentrations on aphid population dynamic is well documented. However, nothing about their chemical ecology is reported in the literature. Aphids are using many chemical signals to communicate with each other or with their environment. For example aphids produce an alarm pheromone to signal the presence of a natural enemy (such as a predator or a parasitoid) in the colony. Moreover, this pheromone is used by natural enemies as a kairomone to locate aphid prey, and is thus at the center of aphid – natural enemies interactions. In this study, the impact of elevated CO2 concentration on the emission of the alarm pheromone in the aphid A. pisum is studied. Using a zNoseTM (Gas chromatograph enabling the fast analyze of the chemical composition of a sample), the kinetic of the EBF emission in real-time is set up for a single individual predated by a coccinellid predator Harmonia axyridis Pallas. This experimentation is done both for aphids reared under ambient atmospheric conditions and for individuals reared under elevated CO2 concentrations. We present the differences in terms of emission dynamic and discuss the potential of these results in terms of biological control. [less ▲]

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See detailImpact of net metering programs on optimal load management in US residential housing – a case study
Georges, Emeline ULg; Braun, J. E.; Groll, E. et al

in Proceedings of 9th International Conference on System Simulation in Buildings (2014, December 11)

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See detailLaïcité à la française : de la prétention universaliste à l'obsession identitaire
Jacquemain, Marc ULg

Conference (2014, December 11)

Le mot "laïcité" est revendiqué par des groupes d'extrême-droite ouvertement racistes et conspirationnistes comme "Riposte laïque". L'article montre que le même imaginaire conspirationniste, sous la même ... [more ▼]

Le mot "laïcité" est revendiqué par des groupes d'extrême-droite ouvertement racistes et conspirationnistes comme "Riposte laïque". L'article montre que le même imaginaire conspirationniste, sous la même structure narrative peut être retrouvé sous des formes débarrassée de leur racisme explicite dans des textes considérés comme "mainstream" au sein de la laïcité, en analysant un texte du Rappel. A partir de là, on tente de montrer que cette "dérivation conspirationniste" peut trouver des prises dans des formulations "progressistes" de la laîcité dès lors que ces formulations partent pour point de départ le point de vue à la fois holiste et idéaliste d'un "laos" toujours-dejà-là, comme chez Peña ruiz [less ▲]

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See detailPlaidoyer pour une recherche-compagne
Havelange, Carl ULg

Conference (2014, December 10)

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See detailLa communauté du ressentiment. Analyse d'une posture énonciative
Servais, Christine ULg

Conference (2014, December 10)

Cette communication propose de caractériser la posture énonciative des « nouveaux réactionnaires » en analysant la manière dont ils s’adressent à leurs destinataires en tant que communauté politique. Par ... [more ▼]

Cette communication propose de caractériser la posture énonciative des « nouveaux réactionnaires » en analysant la manière dont ils s’adressent à leurs destinataires en tant que communauté politique. Par conséquent, on n’y conduit pas une simple analyse des représentations, mais une analyse des postures énonciatives en termes d’adresse au récepteur, étant entendu que, en convoquant une référence, le discours convoque également le destinataire dans un monde, auquel et duquel celui-ci est appelé à répondre. C’est à caractériser cet « appel » au récepteur dans le discours des « nouveaux réactionnaires » que cette intervention est consacrée. [less ▲]

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See detailSur quelques conditions médiatiques de la posture néo-réactionnaire
Durand, Pascal ULg

Conference (2014, December 10)

Ceux qu'il est convenu de rassembler sous l'étiquette sans doute trop extensible de « Nouveaux Réactionnaires » appartiennent pour la plupart à un système inséparablement journalistique et éditorial, dans ... [more ▼]

Ceux qu'il est convenu de rassembler sous l'étiquette sans doute trop extensible de « Nouveaux Réactionnaires » appartiennent pour la plupart à un système inséparablement journalistique et éditorial, dans lequel c’est avec une grande symétrie que se répondent et se rencontrent, d’un coté, des « intellectuels médiatiques », auteurs d’essais à rotation rapide leur garantissant de fortes couvertures de presse et un fort taux de présence dans les émissions de radio et de télévision et, de l’autre côté, des journalistes prolongeant leur propre activité par des recueils de chroniques ou des ouvrages sur des questions de politique ou de société. L’intersection de plus en plus forte de l’univers des médias, de l’univers de l’édition et de l’univers intellectuel est d’autant moins étrangère à ce courant de pensée et de discours que certains de ses représentants les plus visibles apparaissent à l’évidence comme les produits de cette intersection même. Les logiques à l’œuvre dans cette intersection sont bien connues : elles vont de l’emprise croissante de la télévision sur le champ journalistique à l’emprise à son tour croissante de ce champ sur l’univers de la production éditoriale et intellectuelle (comme encore sur les formes du débat et de la représentation politiques). L'objet de la présente communication est de mettre en évidence que la nouvelle parole pamphlétaire semble bien avoir trouvé, dans ce nouvel écosystème discursif dominé par le médium télévisuel et notamment les dispositifs du talk show, les conditions idéales à sa propre montée en force et à la propagation de ses effets. [less ▲]

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See detailIntegrating phylogenetic and environmental niche models to explore speciation mechanisms in the Erythrophleum genus in tropical Africa
Gorel, Anaïs ULg; Fayolle, Adeline ULg; Doucet, Jean-Louis ULg et al

Conference (2014, December 10)

In the context of global climate change, it is of primary importance to understand the species response to climate (habitat tracking or adaptation). In this study we investigated the evolutionary history ... [more ▼]

In the context of global climate change, it is of primary importance to understand the species response to climate (habitat tracking or adaptation). In this study we investigated the evolutionary history of the climatic niche between and within closely related tropical tree species of the Erythrophleum genus (Fabaceae, Caesalpinioideae): E. ivorense, E. suaveolens and E. africanum. Two major hypotheses, the refuge theory and the ecological gradient hypothesis, have been developed to explain the current distribution of tree clades across tropical Africa. To identify the speciation mechanisms, we used a combination of geographic data and environmental factors to quantify the degree of niche conservatism (or divergence). We used two sets of distribution data for the purpose of this study. Species distribution data for the whole of tropical Africa were gathered from herbarium records. Distribution data of the two sister species E. ivorense and E. suaveolens assigned to genetic cluster were available for the lowland tropical forests of western and central Africa. Using a Species Distribution Model (SDM) approach based on MaxEnt algorithm, we tested for the environmental differences (BIOCLIM data) between species and genetic clusters within species. We developed SDMs for each of the three Erythrophleum species (over the whole range) and for each of the five genetic clusters. We quantified the niche overlap using new niche similarity metrics. At species level, the climatic niches differed significantly and overlapped only sligthly, suggesting a parapatric speciation along a climatic gradient. Within the two sister species, the niche of the parapatric central African clusters strongly overlapped, suggesting a secondary contact following the recolonization from different forest refugia. The west African cluster however showed contrasted climatic niches possibly due to either recent (< 100 yrs) climate change in west Africa, or ongoing differentiation on the dry part of the climatic gradient. [less ▲]

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See detailBias-variance decomposition in Random Forests
Louppe, Gilles ULg

Conference (2014, December 09)

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See detailDevelopment and validation of a 3D kinematic-based method for determining gait events during overground walking
Boutaayamou, Mohamed ULg; Schwartz, Cédric ULg; Denoël, Vincent ULg et al

in IEEE International Conference on 3D Imaging (IC3D) (2014, December 09)

A new signal processing algorithm is developed for quantifying heel strike (HS) and toe-off (TO) event times solely from measured heel and toe coordinates during overground walking. It is based on a rough ... [more ▼]

A new signal processing algorithm is developed for quantifying heel strike (HS) and toe-off (TO) event times solely from measured heel and toe coordinates during overground walking. It is based on a rough estimation of relevant local 3D position signals. An original piecewise linear fitting method is applied to these local signals to accurately identify HS and TO times without the need of using arbitrary experimental coefficients. We validated the proposed method with nine healthy subjects and a total of 322 trials. The extracted temporal gait events were compared to reference data obtained from a force plate. HS and TO times were identified with a temporal accuracy ± precision of 0.3 ms ± 7.1 ms, and –2.8 ms ± 7.2 ms in comparison with reference data defined with a force threshold of 10 N. This algorithm improves the accuracy of the HS and TO detection. Furthermore, it can be used to perform stride-by-stride analysis during overground walking with only recorded heel and toe coordinates. [less ▲]

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See detailIdentifying the best technical trading rule: a .632 bootstrap approach.
Hambuckers, julien ULg; Heuchenne, Cédric ULg

Conference (2014, December 07)

In this paper, we estimate the out-of-sample predictive ability of a set of trading rules. Usually, this ability is estimated using a rolling-window sample-splitting scheme, true out-of-sample data being ... [more ▼]

In this paper, we estimate the out-of-sample predictive ability of a set of trading rules. Usually, this ability is estimated using a rolling-window sample-splitting scheme, true out-of-sample data being rarely available. We argue that this method makes a poor use of the available information and creates data mining possibilities. Instead, we introduce an alternative bootstrap approach, based on the .632 bootstrap principle. This method enables to build in-sample and out-of-sample bootstrap data sets that do not overlap and exhibit the same time dependencies. We illustrate our methodology on IBM and Microsoft daily stock prices, where we compare 11 trading rules specifications. For the data sets considered, two different filter rule specifications have the highest out-of-sample mean excess returns. However, all tested rules cannot beat a simple buy-and-hold strategy when trading at a daily frequency. [less ▲]

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See detailL'Aurignacien de la grotte Yafteh et son contexte
Otte, Marcel ULg; Flas, Damien ULg; Zwyns, Nicolas et al

Poster (2014, December 06)

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See detailEvidence based medicine - Tendon and platelet-rich plasma (PRP)
Kaux, Jean-François ULg

in Annual Congress RSBPRM (2014, December 06)

Platelets have known roles in coagulation, inflammatory processes, and immunity modulation; they also have ‘‘restorative’’ properties. Indeed, during degranulation, platelets release different cytokines ... [more ▼]

Platelets have known roles in coagulation, inflammatory processes, and immunity modulation; they also have ‘‘restorative’’ properties. Indeed, during degranulation, platelets release different cytokines and growth factors (VEGF, PDGF, TGF-B, IGF-I, and HGF) that promote angiogenesis, tissue remodeling (bone, skin, muscle, tendon, etc.), and wound healing. PRP is obtained by centrifuging autologous blood to obtain a concentration of platelets, usually between 3 and 10 times that of whole blood, depending on the isolation method. For this reason, different PRP preparation techniques cannot provide a consistently identical final product, but there is currently no international consensus on this issue. Overall, PRP could be an attractive therapeutic option for treating chronic musculoskeletal conditions, such as tendinopathy or plantar fasciitis. Tendons do not have a high metabolic index. Growth factors released by platelets promote tenocyte proliferation, stimulate angiogenesis and have analgesic properties. Thus it could stimulate and accelerate tissue regeneration in animal models. In addition to PRP, optimal tissue quality requires the application of mechanical loads. PRP should be considered for chronic tendinopathies. Indeed, the goal is to initiate an acute inflammatory reaction that quickly moves on to the proliferative phase that involves collagen synthesis. The latter is necessary for appropriate tendon healing. PRP should therefore not be used for acute tendinitis or tenosynovitis. Even if most of the preclinical studies showed that PRP stimulates the tendon healing process, clinical series remain more controversial. Based on literature and our clinical experience, we suggest some ideas for improving this treatment. Optimization of the technique for collecting the PRP is paramount. Different risk factors must be corrected before infiltration, and chronic tendinopathies must be carefully selected. Finally, post-infiltration rehabilitation remains absolutely necessary. Standardisation of the use of PRP remains necessary in order to optimise the results. [less ▲]

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See detailLes ressources génétiques caprines en Algérie
Moula, Nassim ULg; Philippe, François-Xavier ULg; Ait Kaki, Asma et al

Poster (2014, December 06)

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See detailScience at the fringe of the French colonial world: the circulation of Jean-André Peyssonnel’s treatises on medicine and the natural history of Guadeloupe
Vandersmissen, Jan ULg

Conference (2014, December 05)

Jean-André Peyssonnel, born in Marseille in 1694, was a physician who in 1720-1721 earned his spurs in the fight against the plague that ravaged his hometown. Fascinated by the sea and the work of ... [more ▼]

Jean-André Peyssonnel, born in Marseille in 1694, was a physician who in 1720-1721 earned his spurs in the fight against the plague that ravaged his hometown. Fascinated by the sea and the work of fishermen, he turned in following years to the study of marine life. While conducting observational research along the coasts of the Provence and North Africa, he found evidence of the animal nature of coral. This controversial claim caused a heated debate with Réaumur, who blocked his career plans in France. Out of necessity Peyssonnel was forced to accept the post of “Médecin du Roi” in Guadeloupe. In this remote outpost of the French colonial empire, Peyssonnel continued his scientific activities. He received orders to fight a local outburst of leprosy, which resulted in a comprehensive study on the disease. In addition, he produced dozens of treatises on the natural history of the French Antilles, including volcanic, oceanographic, botanical and zoological studies. This contribution tells the story of these remarkable documents which, on their way to the learned world in Europe, passed through many hands. Spread over several intellectual centres – London, Paris, Marseille, Rouen, Bordeaux, Angers – these manuscripts shed a unique light on the circulation of knowledge in a Republic of Sciences turning global. [less ▲]

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See detailLa théorie des humeurs à l’aube de l’Europe vernaculaire
Valenti, Gianluca ULg

Conference (2014, December 05)

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See detailCan Electrical Resistivity Tomography offer us a dynamic view on what happens in the soil-plant continuum?
Garré, Sarah ULg

Conference (2014, December 05)

Root water and nutrient uptake and its relation to environmental factors is one of the least understood components in the terrestrial water balance and is of high importance for water resources management ... [more ▼]

Root water and nutrient uptake and its relation to environmental factors is one of the least understood components in the terrestrial water balance and is of high importance for water resources management, ecology and agriculture. As the processes in the soil-plant continuum are complex and inextricably intertwined, alternative, non-invasive measurement methods are necessary to unravel spatial and temporal dynamics of the system. Electrical resistivity tomography (ERT) has been proposed as a promising technique, since bulk resistivity maps and their temporal evolution may serve as a proxy for changes in soil moisture and pore water salinity, amongst others. However, the variables affecting the measured bulk electrical resistivity often change simultaneously in natural environments and not all influencing factors are yet well understood (e.g. influence of root biomass). Therefore, the method needs field-specific calibration. In addition to limitations due to signal-to-noise ratio and data inversion strategies, this implies that ERT still needs further development and research efforts for its use to characterize the soil-plant continuum. [less ▲]

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See detailRegistres de la langue en néo-égyptien: le cas des Tomb Robberies
Winand, Jean ULg

Conference (2014, December 05)

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See detailL’impact de la réserve cognitive sur le fonctionnement exécutif au cours du vieillissement normal
Simon, Jessica ULg; Gilsoul, Jessica ULg; Collette, Fabienne ULg

Conference (2014, December 05)

Le vieillissement normal s’accompagne d’un dysfonctionnement exécutif important. Or, on sait aujourd’hui qu’il existe une forte variabilité interindividuelle quant aux effets du vieillissement sur la ... [more ▼]

Le vieillissement normal s’accompagne d’un dysfonctionnement exécutif important. Or, on sait aujourd’hui qu’il existe une forte variabilité interindividuelle quant aux effets du vieillissement sur la cognition. Selon l’hypothèse de la réserve cognitive (Stern, 2009), les individus qui auraient développé un haut niveau de réserve résisteraient mieux aux effets du vieillissement que des individus de plus faible réserve cognitive. Dans cette étude, nous avons voulu mesurer l’impact des facteurs de réserve cognitive sur le fonctionnement exécutif au cours du vieillissement normal. Nous avons recruté 59 participants âgés de 60 à 80 ans, sans trouble cognitif ni neurologique. Nous leur avons proposé 8 tâches cognitives évaluant le fonctionnement exécutif : des épreuves d’inhibition (test de Stroop, test de Hayling, subtest Incompatibilité de la TAP), de flexibilité (subtest Flexibilité de la TAP, épreuve d’alternance arithmétique « plus-moins ») et de mise à jour (subtest Lettre-Chiffre de la MEM III, mise à jour de consonnes et tâche de 2-back). De plus, nous leur avons demandé de compléter différents questionnaires évaluant quatre facteurs de réserve cognitive (niveau d’études, parcours professionnel, activité physique et activités de loisir). Nous avons réparti nos participants en deux groupes en fonction de leur niveau de réserve cognitive (faible et haute). Des analyses de t de student (p<0.05) montrent que les participants avec une haute réserve cognitive ont de meilleures performances au subtest de mise à jour des consonnes (p=0,05) ainsi que des résultats quasi significatif pour le score composite de mise à jour (p=0,06) et le subtest de mise de consonnes (p=0,06). Nous avons aussi évalué l’impact spécifique de chaque facteur de réserve cognitive sur les performances au moyen de régressions simples (p<0.05). Les données montrent que le niveau d’étude explique une part significative de la variance du score composite de mise à jour et aux subtests Flexibilité et Lettre-Chiffre ainsi qu’une part quasi significative de la variance au score de mise à jour de consonnes. L’activité professionnelle au cours de la vie explique une part quasi-significative de la variance pour le score de mise à jour (p=0,07) et pour le test de mise à jour de consonnes (p=0,07). Enfin, les activités de loisir, quant à elles, expliquent une part significative de la variance des performances à la tâche du 2-back et une part quasi-significative de la variance des performances au test de Hayling (p=0.06). En conclusion, il apparait que les sujets âgés avec un haut niveau de réserve cognitive montrent de meilleures capacités à certains tests exécutifs uniquement. De plus, nos données suggèrent que tous les aspects du fonctionnement exécutif ne sont pas impactés de façon similaire par les différents facteurs de réserve cognitive. [less ▲]

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See detailOutline of ULg chemical sensors applications for IAQ evaluation
Romain, Anne-Claude ULg

Conference (2014, December 04)

The arrival of the European and National laws* concerning the official labelling of building materials (CE marking) and the respect of concentration values for some compounds regulations in public ... [more ▼]

The arrival of the European and National laws* concerning the official labelling of building materials (CE marking) and the respect of concentration values for some compounds regulations in public buildings as for instance schools, the emergence of the Environmental Assessments of buildings (Breeam, HQE,…) beside the energy performance, as well as the awareness increase of the impact of indoor air quality on the wellness and health (ie ENVIE and Healthvent projects [1]) lead inevitably to the development of new sensing technologies related to the IAQ evaluation. Among the numerous existing measurement devices, electrochemical cells, NDIR and PID ones are the most encountered sensors on the market. The major uses are real time monitoring (CO2) and “friendly” handheld devices. Other applications are also studied in several research labs. Few years ago, the ULg research team investigated the interest of MOS chemical sensors arrays for IAQ evaluation. This presentation aims to review some of the results of those projects. A first is the fast and simple diagnosis of moulds on building materials. The identification of contaminated materials among uncontaminated ones was successful [2-4]. However, the low concentration of the MVOC markers compounds (below 10 µg/m³) and the complexity of the background (material emissions, and VOC content of the indoor air) curbed the use of MOS sensors. Specific preconcentrations have to be developed to improve the diagnosis. Nowadays, with the emergence of new sensing materials and new measurement principles (eg IMS-ion mobility spectrometry [5]), perspectives are again opened. Another project (HEMICPD, Belgian project “Horizontal evaluation method for the implementation of the Construction Products Directive”-Emissions to indoor air [6]) concerned the marking of building materials and one of the tasks was to test the sensors array principle to monitor the compounds emanation from different building material, during 28 days, in emission test chambers. Another goal was to investigate a classification of the materials including their odour level. The results on the use of sensors to evaluate the efficiency of “masking” products pulverised in wallpapers and to manage their use are also explained. [less ▲]

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See detailAdvances in proteomics for the FP7 Venomics project
Degueldre, Michel ULg; Quinton, Loïc ULg; De Pauw, Edwin ULg

Conference (2014, December 03)

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See detailFirst principles study of the structural, electronic and thermoelectric properties of misfit cobaltite
Lemal, Sébastien ULg; Varignon, Julien ULg; Bilc, Daniel ULg et al

Poster (2014, December 03)

In the context of environmental issues that become more and more prevalent in our society, there has been recently an increase of interest for thermoelectric (TE) materials, which have the property to ... [more ▼]

In the context of environmental issues that become more and more prevalent in our society, there has been recently an increase of interest for thermoelectric (TE) materials, which have the property to convert heat into electricity, and vice-versa. Although they do not display exceptional thermopower (in comparison to best thermoelectric like bismuth telluride), oxide materials have attracted some attention for high-temperature TE applications, due to their high stability. Amongst them, CoO2-layered compounds were proposed as good p-type TE candidates. Still, these compounds have been only poorly characterized both theoretically and experimentally. In this work we report a first-principles study of misfit calcium cobaltite (Ca2CoO3)(CoO2)1.618 based on density functional theory and an hybrid functional. The computed structural, electronic and magnetic properties match well the avalaible experimental data. Then the thermoelectric properties can be deduced using the Boltzmann transport formalism within the constant relaxation time approximation and will be discussed. [less ▲]

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See detailDetecting microbial patterns in relation to soil agricultural practices and the plant development stage
Degrune, Florine ULg; Dufrêne, Marc ULg; Taminiau, Bernard ULg et al

Poster (2014, December 02)

Agricultural practices have a strong impact on soil bacteria and fungi. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these ... [more ▼]

Agricultural practices have a strong impact on soil bacteria and fungi. Furthermore, microbial community composition can change with the stage of plant development. We are interested in exploring these effects in relation to changes induced by agriculture and plant stage in soil conditions. Some bacteria are influenced only by the plant stage, which induces changes in soil humidity, pH, nitrates, and carbon. We would thus expect these bacteria to be highly sensitive to these parameters. Other bacteria are affected only by the tillage practice applied. Further study is needed to identify the soil parameters responsible for this effect. The plant stage also has a great impact on fungal community composition. [less ▲]

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See detailLa régulation du marché du travail par les intermédiaires privés
Gérard, Julie ULg

Conference (2014, December 02)

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See detailMid-winter freeze experiment in the Arctic Ocean: Norwegian Young sea ICE cruise (N-ICE2015)
Nomura, Daiki; Granskog, Mats A.; Fransson, Agneta et al

Poster (2014, December 02)

In mid-January 2015, RV Lance will freeze into the ice north of Svalbard, Arctic Ocean at around 83.25°N 30°E, and passively drift with the ice as part of the Norwegian Young sea ICE cruise (N-ICE2015 ... [more ▼]

In mid-January 2015, RV Lance will freeze into the ice north of Svalbard, Arctic Ocean at around 83.25°N 30°E, and passively drift with the ice as part of the Norwegian Young sea ICE cruise (N-ICE2015). Judging from historic sea ice drift trajectories, it is likely that RV Lance will drift in a SW direction and the ship will probably be freed from the ice in mid spring after about two to three months of drift. Thereafter, RV Lance will return to her starting position and start a new drift. Under all circumstances, the ice drift project will end in late June 2015. Throughout the cruise the focus will be on the interaction of the atmosphere-ice-ocean system and the response of the marine ecosystem to the thinner ice regime. The overall goal of the project team is to improve our understanding of the role of the younger ice pack in the Arctic on greenhouse gas fluxes and to ultimately assess whether the Arctic Ocean is a sink or source of greenhouse gases. We plan to conduct long-term synchronous observations of Arctic snow and sea ice biogeochemistry and physics and fluxes of carbon dioxide, methane, nitrous oxide and bromoform. This work targets at filling a crucial gap in our understanding of the role of Arctic sea ice in the climate system. This is done by conducting state of the art observations on Arctic sea ice in the polar night, when observations are basically non-existent. Further we are focusing on the new thinner ice regime, which is even less documented. We aim to understand how the thinner sea ice in the Arctic basin contributes (i) to important greenhouse gas exchange between the atmosphere and ocean and (ii) to aerosol formation, that contribute to the radiative balance of the planet. This work will increase direct collaboration between Japanese and European scientists in the Arctic, and combines complimentary expertise and experience from several international partners to carry out the interdisciplinary work proposed. [less ▲]

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See detailPhysisorbed poly(ethylene oxide) is a robust tether for AFM-based single-molecule force spectroscopy
Willet, Nicolas ULg; Lussis, Perrine ULg; Giamblanco, Nicoletta et al

Conference (2014, December 01)

Atomic force microscopy (AFM)-based single-molecule force spectroscopy is a prevalent tool for the exploration of individual (bio)molecules, providing exquisite information on many molecular-level ... [more ▼]

Atomic force microscopy (AFM)-based single-molecule force spectroscopy is a prevalent tool for the exploration of individual (bio)molecules, providing exquisite information on many molecular-level processes. For example, proteins, DNA, polysaccharides, supramolecular polymers and polyelectrolytes have been investigated, revealing details about the strength of intramolecular interactions, folding and unfolding pathways, mechanics, conformational changes, reactivity, kinetics, etc. For each particular system under investigation, the experimental design is a decisive phase that often involves a multistep chemical protocol, including grafting, derivatization, coupling, (de-)protection, and other functionalization reactions. Procedures of sample preparation are often complex and time-consuming. Hence, there is a need for new general platforms allowing for straightforward sample preparation adapted to single-molecule studies, i.e. a tight attachment to both the substrate and the tip, and a low density to favor single-molecule detection. We report here on the use of poly(ethylene oxide) (PEO) as a tether to probe various properties of individual molecules. The polymeric linker acts as a handle that stably binds to the AFM tip. The simple adsorption of poly(ethylene oxide) to the tip is versatile and provides an appropriate system configuration for the investigation of many different biological and synthetic molecular systems. To attest for this versatility and adequacy with advanced single-molecule investigation, we present different examples of PEO-mediated studies about the unfolding of a synthetic peptide, the mechanochemical behavior of a molecular machine and finally the stability of a metallo-supramolecular complexed polymer. All the requirements for the study of peptide conformation, tiny molecular machines or metallo-supramolecular interactions in solution are here fulfilled. More generally, this method based on non-covalent sorption of PEO on an AFM tip, can be implemented in a wide range of solvents, for the study of many intra- or intermolecular phenomena at the single-molecule level over orders of magnitude of force loading rates. Connecting PEO tethers to a very broad variety of (bio)molecules is a facile and versatile route. The commercial availability of many different functional PEOs makes this tethering strategy even more accessible. [less ▲]

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See detailL'âgisme
Marquet, Manon ULg; Schroyen, Sarah ULg

Conference (2014, December 01)

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See detailTree species diversity effects on soil microbial biomass, diversity and activity across European forest types
Carnol, Monique ULg; Baeten, Lander; Bosman, Bernard ULg et al

Conference (2014, December)

Increasing tree species diversity in forests might contribute to ecosystem-service maintenance, as well as to the reconciliation of regulating, provisioning and supporting services within the frame of ... [more ▼]

Increasing tree species diversity in forests might contribute to ecosystem-service maintenance, as well as to the reconciliation of regulating, provisioning and supporting services within the frame of multifunctional and sustainable forestry. Individual tree species influence biogeochemical cycling through element deposition (throughfall, litterfall), and through microbial activities in the soil. Yet, the influence of mixing tree species on these ecosystem processes is unclear, in particular concerning the microbial diversity and activity in soils. Here we synthesize results from the Exploratory Platform of the FunDivEUROPE project (http://www.fundiveurope.eu/). This network of 209 comparative plots covering a tree diversity gradient of 1 to 5 tree species was established in existing mature forests in 6 European regions. These six focal regions represent a gradient of major European forest types from boreal to Mediterranean forests. We analysed the impact of tree species diversity and the role of other controlling factors on the metabolic diversity of soil bacteria (BIOLOG Ecoplate), soil microbial biomass (fumigation-extraction) and potential nitrification (shaken soil slurry) in the forest floor and the upper organo-mineral soil horizon. Mean values of microbial biomass carbon ranged from 240 (Poland) to 1762 (Germany) mg kg-1 in the forest floor and from 4197 (Italy) to 11207 (Finland) mg kg-1 in the upper organo-mineral horizon. Tree diversity and soil water content were important controlling factors. Statistical models predict microbial biomass to increase in both horizons by 7-8% with each step increase in tree diversity. Metabolic diversity of soil bacteria (% of substrates used) showed high variability both within and between sites. Further results analysed with mixed linear models will be presented and discussed. [less ▲]

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See detailLes intervenants psycho-sociaux face à l’homoparentalité: quels besoins et quels défis?
Scali, Thérèse ULg; D'Amore, Salvatore ULg

Conference (2014, December)

Les intervenants psycho-sociaux sont confrontés à une société changeante qui leur pose de nouveaux défis tant dans leur clinique que vis-à-vis des concepts théoriques auxquels ils se réfèrent. En ... [more ▼]

Les intervenants psycho-sociaux sont confrontés à une société changeante qui leur pose de nouveaux défis tant dans leur clinique que vis-à-vis des concepts théoriques auxquels ils se réfèrent. En particulier depuis 2006 en Belgique, le cadre législatif permet aux couples homosexuels l’accès à la parentalité. Ainsi, les psychologues de la santé sont aujourd’hui face à une réalité qui les interpelle et qui leur demande d’intervenir. Ces interventions sont nombreuses : travail clinique, psychoéducation, sensibilisation dans les écoles, conférences… Mais qu’en est-il réellement du contenu de ces interventions ? La présente recherche a investigué les attitudes des intervenants psycho-sociaux dans les plannings familiaux face à la thématique de l’homoparentalité. Une méthodologie d’investigation groupale (les focus groups) a été utilisée (Kitzinger, Markova & Kalampalikis, 2004). A travers 6 focus groups composés de 4 à 8 participants, des psychologues, médecins, assistants sociaux et juristes ont été amenés à discuter cette question de santé publique à travers l’analyse de leurs pratiques quotidiennes. Les résultats ont mis en évidence trois niveaux : la réalité de terrain des intervenants avec leurs expériences et leurs ressentis, leurs questionnements concrets liés à la méconnaissance du vécu des familles homoparentales, et leurs besoins en termes d’outils. Ces résultats pourront aider à promouvoir la santé et la qualité de vie des personnes homosexuelles en favorisant la compréhension des réactions des professionnels hétérosexuels auxquels ils sont confrontés. [less ▲]

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See detailClub 35 Poster session 2: Thursday 4 December 2014, 08:30-18:00Location: Poster area.
Voilliot, D.; Magne, Jm; DULGHERU, Raluca Elena ULg et al

Poster (2014, December)

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See detailImpact of shading on meiofauna in a Posidonia oceanica meadow
Pete, Dorothée ULg; Gobert, Sylvie ULg

Poster (2014, December)

Posidonia oceanica meadow is an endemic ecosystem of the Mediterranean coasts. A known threat to this ecosystem is aquaculture. In zones of intensive fish production, P. oceanica meadow tends to be less ... [more ▼]

Posidonia oceanica meadow is an endemic ecosystem of the Mediterranean coasts. A known threat to this ecosystem is aquaculture. In zones of intensive fish production, P. oceanica meadow tends to be less healthy or to disappear .One of the reasons for this is a decrease in the light that reaches the leaves (direct shading, increase of water turbidity or of epiphytic algae density). Unfortunately, when the meadow begins to die, it is often too late to act. So, people are trying to find indicators that react early to this kind of perturbations. In this framework, this study focuses on the impact of shading (without nutrient enrichment) on the meiofauna living in the surface sediment of a P. oceanica meadow. An in situ shading experiment was led from the end of May to the end of August 2009, at a depth of 10 m, in a reference P. oceanica meadow. Three shading nets were put in the meadow to reach a light extinction of 50%. A control site was also defined. The first two centimetres of sampled sediment cores were studied. After three months of shading, the total abundance of meiofauna at the shading site was lower than at the beginning of the experiment, while it stayed around the same level at the control site. This difference is mainly due to a decrease in the total number of foraminiferans, nematods, gnathostomulids, copepods and bivalves. However, no significant difference in diversity was observed. At the end of this experiment, it appeared that, contrarily to what is mostly said in the literature, the direct organic enrichment that occurs at fish farms is not the only reason to the modification of the meiofauna communities of the ecosystem. The shading by itself has also an effect. [less ▲]

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See detailRecherche de sensations, sexualité et pornographie à l’adolescence
Puglia, Rosa ULg; Glowacz, Fabienne ULg

Poster (2014, December)

Introduction : L’adolescence est une période tumultueuse caractérisée par des transformations d’ordre physique, psychologique, cognitive et sociale ainsi que par des conduites exploratoires et de ... [more ▼]

Introduction : L’adolescence est une période tumultueuse caractérisée par des transformations d’ordre physique, psychologique, cognitive et sociale ainsi que par des conduites exploratoires et de recherche de sensations dans lesquelles la consommation de pornographie peut prendre part. L’exposition à la pornographie durant l’adolescence peut s’inscrire dans ce processus développemental avec le risque d’influencer les conduites sexuelles du jeune. Cette thématique peut, dès lors, susciter de nombreuses questions. Méthodologie : Notre recherche, réalisée sur une population d’adolescents âgé entre 15 et 19 ans (N=319), vise à analyser les conduites de consommation de pornographie (motivations, représentations et comportements) en lien avec la recherche de sensations, une dimension prégnante à l’adolescence. Plus particulièrement, nous avons analysé les motivations de ces jeunes à visionner des images et films à caractère pornographique et ce qui les amène à arrêter. Nous nous sommes, également, interrogés quant à l’influence de la consommation pornographique au niveau du développement psycho-sexuel et des pratiques sexuelles de ces jeunes. Pour ce faire, nous avons administré à ces jeunes un questionnaire comprenant, en plus des items se rapportant à la sexualité et la pornographie, plusieurs tests évaluant des dimensions du fonctionnement psychologique et social (test de solitude, recherche de sensation, relations aux pairs, délinquance auto-révélée,... ). Résultats : Nos résultats indiquent qu’une majorité des adolescents ont déjà visionné de la pornographie. L’intérêt pour ce média ainsi que son usage augmente avec l’âge, atteint son apogée vers 16-17 ans puis diminue. Cette tendance curvilinéaire se retrouve également dans les conduites exploratoires telles que les conduites déviantes et la recherche de sensations, ce qui nous amène à envisager une désistance spontanée de la consommation de pornographie en fin d’adolescence. Conclusions : Ces résultats montrent l’importance de comprendre la consommation de pornographie dans un processus développemental et nous amène à envisager une désistance spontanée de cette conduite en fin d’adolescence. [less ▲]

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See detail“Negotiating the law: judges, families and court hearings in inheritance cases in Cotonou”
Andreetta, Sophie ULg

Conference (2014, December)

On 14 June 2004, Benin ratified a new Code on Persons and Family – regulating, amongst other things, inheritance matters. Over the last couple of years, the number of inheritance cases handled by state ... [more ▼]

On 14 June 2004, Benin ratified a new Code on Persons and Family – regulating, amongst other things, inheritance matters. Over the last couple of years, the number of inheritance cases handled by state courts has drastically increased in the capital city. How do people understand and use the law? While modern courts, like other public services, have been analyzed as part of everyday governance and the local state in West Africa, I on the other hand will focus on the ways in which the judiciary interprets and implements law. Within that context, hearings are a key moment of legal proceedings. How do litigants argue their cases? How do judges manage to settle inheritance quarrels? Using case studies of inheritance disputes and their litigation under the 2004 ‘Code on Persons and Family’, I try to understand how state laws are understood, utilized, and/or questioned in Cotonou. [less ▲]

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See detailDiscontinuité des liens et souffrance psychique : quelles stratégies adaptatives en situation de précarité sociale ?
Glowacz, Fabienne ULg; Spitz, Jacqueline

Poster (2014, December)

Dans un contexte social en mutation prônant l’autonomie de l’individu, le passage à l’âge adulte pour les jeunes en situation de vulnérabilité économique sociale et relationnelle se révèle un véritable ... [more ▼]

Dans un contexte social en mutation prônant l’autonomie de l’individu, le passage à l’âge adulte pour les jeunes en situation de vulnérabilité économique sociale et relationnelle se révèle un véritable défi. L’objectif de l’étude est de comprendre les ressources et les conduites adaptatives de ces jeunes leur permettant de faire face à la souffrance psychique que génère la discontinuité des liens, et d’éviter la désaffiliation sociale et l’errance. Cette recherche clinique de terrain s’inscrit dans une approche ethno-psychologique par sa méthode. Elle s’appuie sur les récits de 6 jeunes adultes âgés entre 19 et 25 ans rencontrés dans le cadre d’un hébergement temporaire en maison d’accueil. Chaque récit est séquencé et analysé selon plusieurs niveaux : les indicateurs sociologiques du passage à l’âge adulte, les modes de relations des individus au niveau familial et social, les indicateurs de précarité. Le parcours de ces jeunes adultes en situation de précarité sociale, cumulant vulnérabilité relationnelle et vulnérabilité économique, les amène à développer des conduites qui leur permettent à la fois de préserver le lien avec autrui, de s’adapter à l’environnement et de préserver une maîtrise d’une affiliation anxiogène. Leur vécu expérientiel de rupture et de perte continue à s’actualiser dans une nécessaire oscillation entre rapprochement et distanciation, en résonnance avec leur style d’attachement primaire. Conclusion « Etablir le lien sur un mode discontinu » apparait comme un mode d’adaptation à l’environnement à la fois protecteur de leur intégrité psychique et fragilisant leur socialisation. [less ▲]

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See detailOral Abstract session: Stress echo in clinical practice: Friday 5 December 2014, 08:30-10:00Location: Agora.
Magne, J.; Donal, E.; Dulgheru, R. et al

Conference (2014, December)

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See detailPoster session 1: Wednesday 3 December 2014, 09:00-16:00Location: Poster area.
Romano, G.; D'ancona, G.; Pilato, G. et al

Poster (2014, December)

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See detailTrace element kinetics in caged Mytilus galloprovincialis
Richir, Jonathan ULg; Lepoint, Gilles ULg; Donnay, Annick et al

Poster (2014, December)

Trace elements (TEs) remain contaminants of concern because of their persistence, ability to concentrate in organisms and toxicity. The Mediterranean mussel Mytilus galloprovincialis Lamarck, 1819 is a ... [more ▼]

Trace elements (TEs) remain contaminants of concern because of their persistence, ability to concentrate in organisms and toxicity. The Mediterranean mussel Mytilus galloprovincialis Lamarck, 1819 is a relevant bioindicator of TE coastal contamination. However, little research has studied the combined influence of environmental condition changes and physiological processes on their kinetics in that species. Caged M. galloprovincialis were thus immerged in 2 contrasted pristine Corsican (France) coastal environments, the semi-enclosed Diane salty pond and the open Calvi Bay, from February to June 2011. Mussels were regularly sampled to study the kinetics of 19 TEs in their flesh; dissolved and particulate TEs were also monitored. The primary production and the water physico-chemical variables were measured, and meteorological data were purchased from Météo-France. TE kinetics in mussels differed between sites. Mussel spawning, a temperature and saline-induced physiological process that occurred about 10 days later in the Diane pond, was followed by a short time increase of TE levels in the mussel flesh. Mussel contamination also evolved according to changes of their respective environmental TE levels. Raining events temporary led, in the Diane pond, to the water enrichment with TEs, nutrients and detrital material, to peaks of primary production and to the increase of TE concentrations in the mussel flesh. This step by step evolution of TE levels in the environment and mussels was afterwards followed by a rapid return to initial conditions. In the open Calvi Bay, these fast and balanced kinetics were not so obvious, because of the rapid dilution of environmental constrain effects in the Bay. Mussels are often used as bioindicator in estuaries and coastal enclosed meadows with rapidly changing environmental conditions. In such conditions, the influence of the environment on TE kinetics in mussels must be considered, in addition to physiological processes, when monitoring the TE coastal contamination. [less ▲]

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See detailPoster session 6: Saturday 6 December 2014, 08:30-12:30Location: Poster area.
Henri, C.; DULGHERU, Raluca Elena ULg; Magne, J. et al

Poster (2014, December)

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See detailThe influence of bioavailable copper and zinc concentrations on metallothionein levels, DNA damage and gene expression in the polychaete Nereis (Alitta) virens (M. Sars, 1835)
Pini, Jennifer; Richir, Jonathan ULg; Watson, Gordon

Poster (2014, December)

Nereis (Alitta) virens is an ecologically and commercially important polychaete of intertidal soft sediment and an ideal species to investigate long term effects of metals. Using a spike approach, worms ... [more ▼]

Nereis (Alitta) virens is an ecologically and commercially important polychaete of intertidal soft sediment and an ideal species to investigate long term effects of metals. Using a spike approach, worms (1-3 g) were incubated for nine months in sediments spiked at environmentally relevant concentrations of copper, zinc and copper & zinc together: low (copper: 70 mg kg-1, zinc: 200 mg kg-1), medium (copper 120 mg kg-1, zinc: 270 mg kg-1) and high (copper 575 mg kg-1, zinc: 1160 mg kg-1) concentrations. These concentrations were based on an extensive sampling regime of sediment, pore water and worms from seven sites with different levels of contamination across the UK. Worms were fed and maintained under ambient conditions in a flow-through seawater system and sampled at 3, 6 and 9 months. Using BCR sequential extraction, bioavailable metal concentrations in the sediment were assessed in addition to pore water and tissues metal concentrations. The induction of metallothionein (MT) activity, especially at month 6, revealed the detoxification potential of N. virens under metal stress conditions. Significant correlations were obtained between copper bioavailable concentrations in the sediment and MT levels at month 3 and between zinc bioavailable concentrations in the sediment and MT levels at month 6. The highest DNA damage was recorded at month 3 for high copper & zinc combined treatment with 36.44%. Significant correlations were obtained between sediment bioavailable metal concentrations and DNA damage. In addition, the study of metal induced gene expression will reveal for the first time metal regulation process in the polychaete N. virens. This study showed that (1) not only high copper was toxic to N. virens but high copper & zinc combined treatment was the most toxic to the worms and (2) MT and DNA damage were sensitive and reliable endpoints used to evaluate copper and zinc toxicity. [less ▲]

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See detailComment finir, ou la prière faite au théâtre
Dubouclez, Olivier ULg

in Littérature (2014, December)

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See detailWhat can we learn from asteroseismology of β Cephei stars through forward approach modelling?
Salmon, Sébastien ULg; Montalban, J.; Miglio, A. et al

Poster (2014, December)

The beta Cephei pulsating stars present a unique opportunity to test and probe our knowledge on the interior of massive stars. The information we can obtain depends on the quality and number of ... [more ▼]

The beta Cephei pulsating stars present a unique opportunity to test and probe our knowledge on the interior of massive stars. The information we can obtain depends on the quality and number of observational constraints, both seismic and classical ones. The asteroseismology of beta Cephei stars proceeds by a forward approach, which often result in multiple solutions, without clear indication on the level of confidence. We seek a method to derive confidence intervals on stellar parameters obtained by forward approach and investigate how these latter behave depending the seismic data accessible to the observer. We realise forward modelling with help of a grid of pre-computed models and use Monte-Carlo simulations to build confidence intervals on the inferred stellar parameters. We apply and test this method in a series of hare and hound exercises on a subset of theoretical models simulating observed stars. Results show that a set of 5 frequencies (with knowledge of their associated angular degree) yields good seismic constraints. In particular, presence of mixed modes provides a strong diagnosis on the evolutionary state of the star. Significant errors on the determinination of the extent of the central mixed region appear when the theoretical models do not present the same chemical mixture as the observed star. [less ▲]

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