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

Conference (2014, December 12)

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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 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 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 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 detailMeasuring the Effect of Stochastic Perturbation Component in Cellular Automata Urban Growth Model
El Saeid Mustafa, Ahmed Mohamed ULg; Saadi, Ismaïl ULg; Cools, Mario ULg et al

in Procedia Environmental Sciences (2014), 22(Winter), 156168

Urban environments are complex dynamic systems whose prediction of the future states cannot exclusively rely on deterministic rules. Although several studies on urban growth were carried out using ... [more ▼]

Urban environments are complex dynamic systems whose prediction of the future states cannot exclusively rely on deterministic rules. Although several studies on urban growth were carried out using different modelling approaches, the measurement of uncertainties was commonly neglected in these studies. This paper investigates the effect of uncertainty in urban growth models by introducing a stochastic perturbation method. A cellular automaton is used to simulate predicted urban growth. The effect of stochastic perturbation is addressed by comparing series of urban growth simulations based on different degree of stochastic perturbation randomness with the original urban growth simulation, obtained with the sole cellular automata neighbouring effects. These simulations are evaluated using cell-to-cell location agreement and a number of spatial metrics. The model framework has been applied to the Ourthe river basin in Belgium. The results show that the accuracy of the model is increased by introducing a stochastic perturbation component with a limited degree of randomness, in the cellular automata urban growth model. [less ▲]

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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: 12 (3 ULg)
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See detailParticulate soils adherence and surface cleanability: influence of biomacromolecules at interfaces and of substrate hydrophobicity
Toure, Yetioman ULg

Doctoral thesis (2014)

Cleaning of particulate soils is an important issue in food and pharmaceutical production. Understanding the adherence of these soils is a fundamental requirement for improving surfaces cleanability. The ... [more ▼]

Cleaning of particulate soils is an important issue in food and pharmaceutical production. Understanding the adherence of these soils is a fundamental requirement for improving surfaces cleanability. The combination of particles and macromolecules substances appears in many processes. Adsorbed compounds from these mixtures may influence interactions at interfaces and thus fouling and cleaning. This thesis deals with a deeper understanding of the physico-chemical mechanisms affecting soiling and cleanability of open substrates in the presence of biomacromolecules (dextran, bovine serum albumin – BSA, beta-lactoglobulin – β-LGB). Model substrates were chosen according to their hydrophobicity. The influence of macromolecules was examined by introducing them in the quartz suspension taken as a model of hard hydrophilic soil used for soiling, or by conditioning the substrate prior to soiling. The substrates were pretreated with ethanol (-Eth.), piranha or UV-Ozone (-UVO); soiled by spraying the quartz suspensions, then dried, before cleaning assessment. The removal of the soiling particles was evaluated after exposure to water in a radial flow chamber (RFC). Auxiliary characterizations were surface tension and contact angle measurements, surface analysis of the substrate by X-ray photoelectron spectroscopy (XPS) and Scanning electron microscopy (SEM). The interpretation of XPS data allowed the complexity due to the ubiquitous presence of organic contaminants to be coped with, and the surface composition to be expressed in terms of both the amount of adlayer and the mass concentration of adlayer constituents. The contact of substrates with proteins led to their adsorption, which dominated the composition of the organic layer with respect to contaminants initially present, and was not markedly desorbed upon rinsing. Dextran was easily removed in presence of water, independently on the substrate nature. Surface hydrophobicity was shown to influence the morphology of the aggregates resulting from drying. The rounder aggregates formed on polystyrene when soiling was performed with suspension in pure water are more sensitive to wall shear stress than flatter ones formed on more hydrophilic substrate. This is the result of the competing processes of droplet rolling and coalescing, on the one hand, and droplet spreading, on the other hand. It affects the shape and compactness of the adhering aggregates, the efficiency of shear forces upon cleaning and finally, the adherence of soiling particles. The presence of proteins (either native or denatured) at the interface improved strongly the cleanability of more hydrophilic substrate (glass, StSteel-UVO). This is attributed to the lower surface tension. The dependence of cleanability on capillary forces, and in particular on the liquid surface tension, is predominant as compared with its dependence on the size and shape of the soiling aggregates, which influence the efficiency of shear forces exerted by the flowing water upon cleaning. The cleanability of less hydrophilic substrate (stainless steel only pre-cleaned with ethanol) did not change markedly in the presence of proteins; this may be due to a more complex interaction between surface tension and contact angle, on one hand, and a more complex interaction between proteins and contaminants, on the other hand. The presence of dextran did not affect the cleanability, as neither the liquid surface tension nor the contact angle was appreciably affected. [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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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 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 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 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 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 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 detailKracauer : Photographie et Wirklichkeit
Barbion, Sébastien ULg

Scientific conference (2014, December 12)

Detailed reference viewed: 9 (4 ULg)