Last 7 days
Bookmark and Share    
Full Text
See detailHealth Literacy: Eduquer pour mieux soigner
Bragard, Isabelle ULg

Scientific conference (2016, June 24)

Detailed reference viewed: 17 (0 ULg)
Full Text
See detailMarijan Molé à l'aude du nouveau comparatisme indo-iranien
Swennen, Philippe ULg

Conference (2016, June 24)

Detailed reference viewed: 15 (0 ULg)
Peer Reviewed
See detailEmerging Hybridities under Networked Agribusiness in Argentina
Delvenne, Pierre ULg

Conference (2016, June 24)

Science and Technology Studies (STS) are paying greater attention to the interactions between new technologies and politico-economic orders. Dynamics of promises and expectations with regard to ... [more ▼]

Science and Technology Studies (STS) are paying greater attention to the interactions between new technologies and politico-economic orders. Dynamics of promises and expectations with regard to technological developments, and their uptake, play a major role in shaping political-economic policies, institutional practices and wider societal mutations. Informed by the theoretical perspective of co-production (Jasanoff 2004), this paper addresses the political economy of GM soy agriculture in Argentina as both epistemic and social orders. We engage ‘micro’ perspectives looking at situated social experiments with farmers and their interrelations with ‘macro’ phenomena such as capital-labour relations and forms of ‘neoliberalism’. We find that the emerging hybridities in present time’s Argentina are caught between the promissory futures of agroindustrial innovation and the historical, political and material conditions of agricultural production that give rise to these presents in the first place. Looking at three of such hybridities (the blurring of boundaries between modern/national, agriculture/industry and leasing/ownership), we highlight the ways in which elements of political-economic structures and human agency got bound up with technoscientific advances (Jasanoff 2015). Our contribution reveals the importance of the concept of ‘network’ to make sense of the dominant logic of agribusiness and it amounts to ‘rugged’ approach to networks with due attention to the complex topographies of circulating power and morality. [less ▲]

Detailed reference viewed: 13 (1 ULg)
Full Text
Peer Reviewed
See detailLa joie qui vient après l'attente. Retour sur la parution de J.-M. Mouillie et J.-P. Narboux, Sartre. L'Être et le néant. Nouvelles lectures, Paris, Les Belles Lettres, 2015, 212 p.
Recchia, Fabio ULg

in Année Sartrienne (L') (2016)

Cette publication consiste en une recension des "Nouvelles lectures" de "L'Être et le Néant", publiées à l'occasion de la sélection de ce texte à l'agrégation externe de philosophie 2015. Il s'agit de ... [more ▼]

Cette publication consiste en une recension des "Nouvelles lectures" de "L'Être et le Néant", publiées à l'occasion de la sélection de ce texte à l'agrégation externe de philosophie 2015. Il s'agit de faire retour sur cet événement que constitue la parution d'un tel recueil proposant, selon nous, une "relecture franche" de l'Essai de 1943 - une texte longtemps tenu pour le parent pauvre de la philosophie de Sartre, dans la mesure où cet ouvrage compte peu de monographies spécialisées à son sujet. Identifiant par ailleurs que ces "Nouvelles lectures" renvoient à nouvelle génération de chercheurs, cette recension souligne de quelle manière ce recueil apporte un commentaire lumineux de l'appareillage ontologique de l'Essai de 1943, témoigne en outre d'une attention particulièrement vive à l'égard des thématiques de l'individuation ainsi que de l'intersubjectivité chez Sartre, et articule enfin un dialogue entre les champs des "Études sartriennes" et celui de la philosophie de l'esprit contemporaine. [less ▲]

Detailed reference viewed: 11 (1 ULg)
Full Text
Peer Reviewed
See detailReceding-Horizon Control of Distributed Generation to Correct Voltage or Thermal Violations and Track Desired Schedules
Soleimani Bidgoli, Hamid ULg; Glavic, Mevludin ULg; Van Cutsem, Thierry ULg

in Proceedings of the 19th PSCC (2016, June 23)

This paper presents a real-time, centralized control system acting on the active and reactive powers of distributed generators when the network experiences voltage and/or thermal limits violation. The ... [more ▼]

This paper presents a real-time, centralized control system acting on the active and reactive powers of distributed generators when the network experiences voltage and/or thermal limits violation. The control resorts on multi-step receding-horizon optimization. The objective is to minimize the deviations of Dispersed Generation Units (DGU) active and reactive powers from reference values. The reactive power corrections have priority over the active ones. Furthermore, the formulation is such that DGU powers are restored to their desired schedule as soon as operating conditions allow doing so. Three modes of operation of the proposed controller are presented, involving dispatchable units as well as DGUs operated to track maximum power output. The effectiveness of the proposed control is illustrated through detailed simulations of a 75-bus, 11-kV system hosting 22 DGUs. [less ▲]

Detailed reference viewed: 78 (25 ULg)
Full Text
Peer Reviewed
See detailPublic Education Expenditures, Growth and Income Inequality
Artige, Lionel ULg; Cavenaile, Laurent

Conference (2016, June 23)

Detailed reference viewed: 23 (1 ULg)
Full Text
See detailInfluence du conditionnement et de la déshydratation mécanique sur le séchage des boues d'épuration
Pambou, Yvon-Bert ULg

Doctoral thesis (2016)

Wastewater treatment plants generate a byproduct which is found in the form of a colloidal suspension, known under the generic term of sludge. At present time, its valorization after a treatment step is a ... [more ▼]

Wastewater treatment plants generate a byproduct which is found in the form of a colloidal suspension, known under the generic term of sludge. At present time, its valorization after a treatment step is a topical environmental issue. This work focuses on the study of the impact of the conditioning step, i.e., the addition of chemicals such as coagulants and flocculants, on the mechanical dewatering and thermal drying steps. The coagulant used (polyaluminum chloride) is combined with a cationic polymer type (flocculant), ranging from linear to complex structures (branched and cross-linked), two of the four flocculants tested with the coagulant are linear structures only differing by their molecular weight. Specifically, the study highlights the role of polyaluminum chloride (PAX-14) as a co-activating agent of the water release during the flocculation stage, when it is combined with the polymer. To better understand the link between this flocculation stage and mechanical dewatering and drying performances, many conditioning ways have been studied and the flocculated sludge obtained was dewatered under a constant pressure using a normalized filtration-expression cell. The dewatered cake obtained after the filtration stage was then characterized in terms of dry solids content, textural properties, desorption isotherms, and finally submitted to a convective drying post-treatment, after the sample was extruded through a circular diameter of 14 mm and cut at a height of a same length, yielding cylindrical samples with a mass of around 2.5 g. Results show that, dual conditioning by applying PAX-14 as a coagulant is an excellent way to improve the cake dryness after the mechanical dewatering step. The interaction between the liquid suspension with polyaluminum chloride and the flocculant offers more attractive yields compared with the use of single conditioning to flocculate the bio-material. Moreover, the efficiency of the two linear flocculants including the use of PAX-14, were shown to produce rather similar performances, while for the same coagulant coupled with trendy or branched macromolecules produce significant differences in terms of increase in dry solids content of the dewatered cake, differences for which the polymer having the highest degree of cross-linking appears to be more beneficial to remove more water contained in the floc after filtration. Sorption isotherms, curves reflecting the hygroscopicity of the product were carried out on the dewatered samples using the DVS equipment (Dynamic Vapor Sorption). Firstly, these experiments confirmed that, curves obtained for wastewater sludge exhibit a sigmoidal shape characteristic of type II, and secondly, an impact of dual PAX-14/polymer conditioning on hydro-textural properties remains difficult to assess. Based on the statistical parameters, GAB equation appears the best formulation to model the sludge sorption isotherms of the Grosses-battes wastewater treatment plant. By studying the texture evolution of sludge for different levels of cake dryness, this work has compared the sludge mechanical properties from the four conditioning types. Globally, results show a more pronounced firmness of the dewatered cake when using the couple PAX-14/polymer in the flocculation stage compared to the single conditioning one. However, from the determined sludge texture parameters it seems difficult to argue that the contribution of both coagulant and cross-linked polymers is better than the association involving aluminum polymerized salt and linear flocculants. Finally, it can be noted that the effects of under or overdosing of chemical can lead to the destruction of material and then, a decrease of sludge cohesion drying rate can be observed. In order to access at the effect of the dual PAX-14/polymer conditioners on drying behavior of sludge samples, some characteristics associated with drying kinetics were compared. According to the statistical analysis, the most significant results were obtained by the association involving PAX-14 and the use of cross-linked flocculants, for which, the polymer which has the highest degree of cross-linking provides a better propensity to remove water contained into flocs after filtration. Linear polymers were shown to produce the same performance. During drying, the texture of the material evolves, including shrinkage and voids development. By X-ray microtomography, this phenomenon has been characterized. The curves of shrinkage volume exhibited a linear decrease with two straight line periods, which the transition seems to be correlated to the sludge water behavior. On the first period, the shrinkage volume can be correlated to the quantity of evaporated water. The texture of the solid material does not hamper the shrinkage process. However, during the second period, the structure of solid stiffens and then influences the shrinkage phenomenon: water is replaced by air and porosity is created. This period corresponds to a phase of decreasing deformation rate (ε) marking the gradual rigidifying of the matrix until no further deformation was observed, the solid was totally rigidified. After drying, the final volume reduction was found to be close to 70% of the initial sample volume for linear and cross-linked flocculants combined with PAX-14, while it was around 75% of the sample initial volume in the case of branched flocculant co-conditioning with the sample coagulant. According to this result, shrinkage depends on both the nature of the sludge and the polyelectrolyte types or dosage. An impact was also found of chemical conditioners on the evolution of porosity. For sludge flocculated by single conditioning, it appears that the porosity was centered on the solid material while for dual conditioning a porosity structured in slats, was identified. This difference in internal structure of the porosity explains the difference in drying kinetics, including the modification of the exchange surfaces available and the average distance of transfer, allowing acceleration or a slow-down of the water removal. [less ▲]

Detailed reference viewed: 62 (5 ULg)
Full Text
See detailImpact of fire on resilience of tropical dry forests: miombo in Lubumbashi (Democratic Republic of Congo)
Hick, Aurélie ULg

Conference (2016, June 23)

Dry tropical forests are widespread in continental Africa where they account for 70-80% of forested area. Miombo is a dry forest characterized by the dominance of trees in the genera Brachystegia ... [more ▼]

Dry tropical forests are widespread in continental Africa where they account for 70-80% of forested area. Miombo is a dry forest characterized by the dominance of trees in the genera Brachystegia, Julbernardia and Isoberlinia. Dry-season fires are a characteristic feature of these forests. Fire is not a frequent natural disturbance but they originate from anthropic. The impact of fire on forest species depends on the intensity and timing in relation to plant phenology. Due to urban pressure, more than 85% of woodland forests were converted to savannahs given several degree of forest degradation in the landscape. After a disturbance, tropical forest ecosystem can return to a trajectory close to the original ecosystem. The time it takes for this ecosystem recover to its predisturbance ecological condition is termed resilience. Loss of resilience can trigger a shift to another ecological state with ecosystems that are different in species and/or that are different in their functional and structural aspects. The broad goal of our study was to examine impact of fire on resilience of miombo after human disturbances. Mosaic of the MODIS 500m burned area product from 2002 to 2012 were used to calculate return frequency of fires around Lubumbashi. Five degrees of miombo degradation have been established : no degraded forest/little disturbed (level 1), moderately degraded forest (level 2), degraded forest (level 3), severely degraded forest (level 4) et deforested (level 5). For each degree of degradation, 9 circular plots (18 m radius, 0.1ha) were established, excepted for level 4 where 8 plots were laid. Within each circular plot, all woody individuals >= 2 cm diameter at breast height (DBH) were tagged, measured (height and diameter) and identified. Tree seedlings < 2 cm DBH and of height > 20cm were also sampled and identified. Herbaceous biomass was measured. Floristic composition in level 4 corresponded to fire-tolerant species. In other degree of forest degradation, most abundant species in mature trees consisted to tolerant or semi-tolerant species. Floristic composition of regeneration in most degraded degree consisted to a mixte of miombo species and fire-tolerant species. Fire has an impact on resilience of miombo after human degradation. Level 4 corresponded to a typical floristic community of a chipya habitat, where all woody species are fire tolerant. Fire can lead degraded miombo toward an alternative stable degraded states. [less ▲]

Detailed reference viewed: 30 (3 ULg)
Full Text
See detail« Comment le réel a déjoué mes plans » : de quelques romans contemporains sur l’emprise par le récit
Claisse, Frédéric ULg; Huppe, Justine ULg

Conference (2016, June 23)

L’un des mérites paradoxaux des pratiques de storytelling, que C. Salmon a contribué à faire connaître au public francophone, réside dans le crédit dont bénéficie aujourd’hui l’idée de pouvoir du récit ... [more ▼]

L’un des mérites paradoxaux des pratiques de storytelling, que C. Salmon a contribué à faire connaître au public francophone, réside dans le crédit dont bénéficie aujourd’hui l’idée de pouvoir du récit. Cette idée place les producteurs littéraires dans une position ambivalente : perçu, d’un côté, comme une menace à leur autonomie et une atteinte au capital fictionnel dont ils sont les dépositaires légitimes, cet « art de raconter des histoires » est aussi une arme à détourner dans une entreprise de guérilla contre-narrative, voire un moyen pour la littérature de reconquérir ses pouvoirs premiers. Dans cette logique d’affrontement, on s’est cependant peu soucié, au fond, de ce que les fictions littéraires elles-mêmes avaient à dire sur le sujet : s’il est vrai que le récit est une prise sur le monde et un moyen d’emprise sur autrui, comment prennent-elles en charge ces situations ? La diffusion tant des pratiques de storytelling que de leur dénonciation ne pouvait rester sans effet sur la production littéraire. Or, le pouvoir du récit est aujourd’hui un thème régulièrement frayé par les romanciers, dans une série de textes qui présentent des convergences remarquables du point de vue des situations qu’ils décrivent. Dans Un Roman russe (2007), Emmanuel Carrère voit sa vie bouleversée pour avoir publié un récit érotique adressé à la femme qu’il aimait, décrivant les réactions de celle-ci à la lecture de son texte lors d’un voyage en train programmé par le narrateur. La même tentation démiurgique de (re)construction de la réalité par le récit habite le héros du triptyque d’Antoine Bello (Les Falsificateurs 2007 ; Les Éclaireurs 2009 ; Les Producteurs 2015), recruté par une organisation secrète, le Consortium de Falsification de la Réalité, pour laquelle il récrit littéralement l’histoire en falsifiant des archives sur la base de scénarios qui finiront par échapper à leurs créateurs, déclenchant une crise de conscience lorsque le héros découvre qu’Al-Qaïda est en réalité le produit d’une saga scénaristique qui a mal tourné. Dans La Revanche de Kevin (2015), Iegor Gran fait preuve de la même cruauté à l’égard de son protagoniste : pour dénoncer les faux-semblants du monde littéraire, Kevin H. fait lui-même œuvre d'imposture, et finit piégé par ses propres mystifications. Karoo de Steve Tesich (1998), devenu depuis sa traduction française en 2012 un véritable phénomène littéraire, participe des mêmes ressorts narratifs : écrivain raté, incapable de s’enivrer comme de montrer son affection à son fils, Saul « Doc » Karoo parachève sa propre destruction en appliquant à son existence les mêmes recettes qu’il inflige aux mauvais scénarios que Hollywood lui demande de récrire. Dans chacun de ces textes, le protagoniste peut faire siens les mots de Carrère au sujet de son récit censé « faire effraction dans le réel »: « le réel a déjoué mes plans ». Avec leurs personnages-scénaristes, mauvais démiurges châtiés par un réel plus résistant que leurs tentatives de le scripter, ces romans (d)énoncent cette modalité narrative du pouvoir que Citton appelle scénarisation, ou capacité d’agencer le comportement d’autrui à travers l’acte de narration. Mais il s’agit d’un savoir immanent à ces romans, une connaissance de la fiction sur elle-même, relevant de sa fonction cognitive. Récits conscients de l’emprise du récit, ils engagent une autre forme de réflexivité que celle des romans que la critique anglo-saxonne qualifie de « postmodernes », qui mettaient en scène leur propre fonctionnement romanesque : assumant pleinement leur statut fictionnel, ils ne jouent de la frontière entre réalité et fiction que pour mieux conforter l’idée que la réalité, bien que médiée et construite par les récits, « déborde » sans cesse. S'ils ne s'opposent pas frontalement au « Nouvel Ordre narratif », ces romans thématisent les effets perlocutoires des récits, mais surtout leur insuffisance face à la force de rappel du réel. Notre communication analysera ces dispositifs fictionnels d’un point de vue formel et socio-pragmatique. [less ▲]

Detailed reference viewed: 28 (2 ULg)
Full Text
Peer Reviewed
See detailDiaspore heteromorphism in the invasive Bromus tectorum L. (Poaceae): sterile fl orets increase dispersal propensity and distance
Monty, Arnaud ULg; Maebe, Laura ULg; Mahy, Grégory ULg et al

in Flora (2016)

Within a species, the distance travelled by a particular diaspore depends on its morphology. In Poaceae, the presence of terminal sterile florets can lead to diaspore heteromorphism, which may influence ... [more ▼]

Within a species, the distance travelled by a particular diaspore depends on its morphology. In Poaceae, the presence of terminal sterile florets can lead to diaspore heteromorphism, which may influence dispersal. We tested the hypothesis that the presence of sterile florets favored dispersal in Bromus tectorum L., an invasive grass in the Western US. We used field and controlled experiments to study the dispersal of caryopses with and without sterile florets attached (respectively complex and simple diaspores), as well as pieces of inflorescence that detached from the mother plants. We considered both primary and secondary dispersal, as well as abiotic and biotic dispersal agents. The distance travelled by the diaspores and their attachment to animal fur were related to the presence and number of sterile florets. Abiotic agents moved diaspores over relatively short distances, both in terms of primary and secondary dispersal. A significant proportion of diaspores attached to fur, suggesting a potential for dispersal over longdistances. Complex diaspores were better dispersers than simple ones (and pieces of inflorescence), and this pattern was consistent across the study. However, among complex diaspores, the number of sterile florets had little or no influence. Considering primary and secondary dispersal by abiotic and biotic agents provided a general picture of the dispersal ecology of B. tectorum. For all the dispersal steps and dispersal agents we studied, the presence of sterile florets favored dispersal. These results highlight the functional significance of diaspore heteromorphism induced by floret sterility in the dispersal of Poaceae. [less ▲]

Detailed reference viewed: 7 (2 ULg)
Full Text
See detailOn Generalized Hölder-Zygmund Spaces
Kreit, Damien ULg

Doctoral thesis (2016)

To study the regularity of functions, many functional spaces have been introduced during the 20th century. Among them, let us mention the Hölder-Zygmund spaces \Lambda^{\alpha}(\R^{d}) and the Besov ... [more ▼]

To study the regularity of functions, many functional spaces have been introduced during the 20th century. Among them, let us mention the Hölder-Zygmund spaces \Lambda^{\alpha}(\R^{d}) and the Besov spaces B_{p,q}^{\alpha}(\R^{d}) where \alpha>0 somehow indicates the regularity of their elements (p,q\in ]0,+\infty]). The Hölder-Zygmund spaces are particular cases of Besov spaces in the sense that \Lambda^{\alpha}(\R^{d})=B_{\infty,\infty}^{\alpha}(\R^{d}). A generalization of Besov spaces has been introduced in the middle of the seventies and is still studied nowadays. This new type of space allows a deepest study of the regularity of functions. In this thesis, we start from this generalization in order to introduce a generalization of Hölder-Zygmund spaces. The first aim of this thesis is to show that most classical properties of Hölder-Zygmund spaces can be transposed to their generalized version. Among others, a complete characterization of these spaces in terms of wavelet coefficients is proved, which opens their use in the context of the signal analysis. The second aim of this thesis is to introduce a generalized version of the pointwise Hölder spaces similarly to their global version. We then show that most properties of the global spaces can be transposed to their generalized pointwise version. Finally, we study the regularity of some financial stochastic processes. [less ▲]

Detailed reference viewed: 27 (8 ULg)
Full Text
See detailAssaying asparagine content in a complex matrix using a spectrophotometric method
Lecart, Brieuc ULg; Jacquet, Nicolas ULg; Anseeuw, Laurent et al

Poster (2016, June 23)

In this study we show, on 15 wheat varieties, the ability to assay the asparagine content in a complex matrix such as wheat flour by a simple spectrophotometric assay. This method is easier, faster and ... [more ▼]

In this study we show, on 15 wheat varieties, the ability to assay the asparagine content in a complex matrix such as wheat flour by a simple spectrophotometric assay. This method is easier, faster and cheaper than conventional chromatography analysis and allow to discriminate quickly which materials has high or low level of this amino acid. Asparagine is an amino acid present in free form in the food biomass and has the property of reacting with the free sugars during the Maillard reactions that occur during baking at temperatures above 120°C. The Acrylamide resulting from this reaction chain has been identified as reprotoxic, genotoxic and carcinogenic in animals since 1986. The present method allowed us to identify wheat varieties with significantly lower or higher asparagine contents (α=0.05). Therefore, this method can be used to identify wheat varieties or other plants with low asparagine content to use preferentially in products designed for food. [less ▲]

Detailed reference viewed: 15 (2 ULg)
Full Text
See detailDix ans de ``Maths à Modeler à Liège'' ou comment un enseignant/chercheur s'invite dans des classes du secondaire
Rigo, Michel ULg

Conference given outside the academic context (2016)

Les missions d'un professeur d'université sont multiples : recherche, enseignement mais aussi citoyenneté. Depuis une dizaine d'années, je réalise de multiples activités de sensibilisation aux ... [more ▼]

Les missions d'un professeur d'université sont multiples : recherche, enseignement mais aussi citoyenneté. Depuis une dizaine d'années, je réalise de multiples activités de sensibilisation aux mathématiques : exposés, activités ludiques en petits groupes, etc. En répondant modestement à la question : "les maths ça sert à quoi ?", le but recherché est de démontrer l'utilité souvent méconnue des mathématiques, et de la recherche dans ce domaine (Google, réseaux sociaux, jeux vidéos, magie, etc.). Dans cette présentation, je dresserai tout d'abord l'historique du projet et tenterai d'analyser les actions menées. Ensuite, l'auditoire assistera à un tour de mathémagie et participera, de façon interactive, à un jeu démontrant l'importance du concept de preuve en mathématique. Ces jeux sont tirés de "Situations-Recherche pour la classe" développées par des chercheurs grenoblois. Enfin, j'expliquerai comment des étudiants de l'ULg (bacheliers, masters, étudiants à l'agrégation) et des doctorants participent à cette action. [less ▲]

Detailed reference viewed: 19 (2 ULg)
Full Text
See detailInsect pathogenic Aspergillus species in mosquito (Diptera: Culicidae) control compared to Metarhizium anisopliae
Bawin, Thomas ULg

Doctoral thesis (2016)

Many mosquito (Diptera: Culicidae) species are vectors responsible for the transmission of infectious diseases of medical and veterinary importance. Risk for infection considerably increased during the ... [more ▼]

Many mosquito (Diptera: Culicidae) species are vectors responsible for the transmission of infectious diseases of medical and veterinary importance. Risk for infection considerably increased during the last decades due to climate changes and increasing global trade. Vector control is essential for public health management. Integrated pest management is now promoted due to harmful side effects of the chemical insecticides classically used for mosquito control and insect resistance development. This PhD thesis takes part in the selection process of insect pathogenic fungi. Three biological models (Aspergillus clavatus Desmazieres, Aspergillus flavus Link, and Metarhizium anisopliae (Metschnikoff) Sorokin) were selected and investigated regarding their spore insecticidal activity, mode of action, and selectivity. Throughout this scheme, the use of agricultural materials and derivatives in fermentation processes was emphasized. Production methods and insecticidal potential of the fungi were first investigated. On the one hand, the two Aspergillus species were compared to M. anisopliae regarding their spore production when cultured on agro-industrial substrates (white rice and wheat bran) and their insecticidal effect on larvae of the southern house mosquito, Culex quinquefasciatus Say. Our results showed that both substrates are suitable to culture the three insect pathogenic fungal species; but wheat bran-based media increased from 3 to 7-fold the spore yields in solid-state compared to white rice-based media. Also, insect pathogenic Aspergillus species were suggested to yield in similar spore levels in such conditions (in a range of 10^9 spores per g of substrate) and be as virulent against mosquito larvae compared to M. anisopliae. On the other hand, a bioreactor design intended to support large-scale production on agricultural materials by combining the technological advantages of submerged and solid-state fermentations was implemented using A. clavatus. This system allowed facility in recuperation and purification of spores (confined on a packed solid substrate) that retained virulence against mosquito larvae; but also metabolites (contained in a circulating liquid medium) that showed insecticidal effect. The mechanisms responsible for the insecticidal effects of the spores, and their selectivity were then investigated. On the one hand, the invasion routes of A. clavatus spores on mosquito larvae were investigated by light and electron microscopy. Histological observations suggest that toxins secreted by active germinating spores of A. clavatus in the digestive tract altered the larval tissues, leading to necrosis and causing larval death. Fungal proliferation and sporulation then occurred during a saprophytic phase. Such action mode also probably occurred in the case of the two other species. On the other hand, the insecticidal activity of the fungi was assessed against the pea aphid, Acyrthosiphon pisum Linnaeus. Adult A. pisum aphids were susceptible (increased mortality and decreased reproductive potential) to the three fungal species. As a consequence, these fungi would probably be able to infect a broad spectrum of insect hosts (whatever terrestrial or aquatic) once released in the environment. The implications of the results for mosquito control and application strategies are finally discussed, and perspectives for future works proposed. [less ▲]

Detailed reference viewed: 28 (9 ULg)
Full Text
Peer Reviewed
See detailUsing phytostabilisation as a way to conserve threatened endemic species from the Southeastern D.R. Congo
Boisson, Sylvain ULg; Le Stradic, Soizig ULg; Seleck, Maxime ULg et al

Conference (2016, June 22)

Metalliferous outcrops of the southeastern Democratic Republic of Congo are recognized as some of the largest copper-cobalt deposits of the world. They support unique vegetation with around 600 ... [more ▼]

Metalliferous outcrops of the southeastern Democratic Republic of Congo are recognized as some of the largest copper-cobalt deposits of the world. They support unique vegetation with around 600 metallophyte species including rare and endemic species. Since 1900s, the exploitation of the Cu-Co outcrops in D.R. Congo has considerably increased, impacting environment and putting public health at risk. Phytostabilisation is a suitable technology to decrease the bioavailability of heavy metals in highly polluted soils. This technic has been successfully implemented in the vicinity of Lubumbashi with the grass Microchloa altera. The long term maintenance of such technic requires a good understanding of the interspecific relationship like competition and facilitation. This study aims to test the success of establishment of four herbaceous species from the southeastern DRC presenting conservation priority and to assess the potential role of M. altera as nurse plant in this context. Two annual species and two perennial species were sown in experimental design with soil amendments crossed with vegetation cover. The emergence, the growth and the survival were followed during the vegetation season and the resprout was measured for perennial species. M. altera had a distinct effect on the emergence and the survival of the annual and perennial species but affected negatively the growth of individuals for all species. [less ▲]

Detailed reference viewed: 18 (1 ULg)