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See detailNos écosystèmes sont-ils des alliés pour lutter contre le changement climatique?
Heinesch, Bernard ULg

Conference given outside the academic context (2016)

Les écosystèmes terrestres jouent un rôle dans le changement climatique. Ils peuvent notamment échanger des gaz à effet de serre avec l’atmosphère. Ils peuvent par exemple émettre ou séquestrer du CO2, du ... [more ▼]

Les écosystèmes terrestres jouent un rôle dans le changement climatique. Ils peuvent notamment échanger des gaz à effet de serre avec l’atmosphère. Ils peuvent par exemple émettre ou séquestrer du CO2, du CH4 et du N2O en fonction du type d’écosystème, de la façon dont l’homme les exploite et des conditions climatiques. Dans cet exposé, des exemples concrets d’expériences menées sur des forêts, des cultures ou des prairies wallonnes seront utilisés pour illustrer les avancées scientifiques récentes dans le domaine et apporter des réponses à des questions du type: «Est-ce qu’une grande culture permet de stocker du carbone ? Et une prairie ? Que devient le bilan si la prairie est pâturée par du bétail ? Quelles pratiques d’exploitation pourraient améliorer le bilan ?» Des exemples de projets menés au sein des écoles secondaires et associant les élèves et des chercheurs seront aussi présentés. [less ▲]

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See detailSeasonal variation in human brain function
Vandewalle, Gilles ULg

Conference (2016, August 25)

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See detailEtude des rôles du produit d'expression du gène M138L du virus Myxoma dans la pathogénie de la myxomatose
Boutard, Bérengère ULg

Doctoral thesis (2016)

Myxoma virus belongs to the Poxviridae family and induces a severe and often lethal disease called myxomatosis in the European rabbit (Bertagnoli & Marchandeau, 2015). Numerous genes of the virus encode ... [more ▼]

Myxoma virus belongs to the Poxviridae family and induces a severe and often lethal disease called myxomatosis in the European rabbit (Bertagnoli & Marchandeau, 2015). Numerous genes of the virus encode for proteins with immunomodulatory functions (Spiesschaert et al., 2011; Zuniga, 2002). Among them, it has been demonstrated that the virus encodes for an α-2,3-sialyltransferase (Jackson et al., 1999; Markine-Goriaynoff et al., 2004b) that catalyzes the transfer of sialic acid to the N and O-glycans of glycoproteins and glycolipids (Varki & Schauer, 2009). Glycans, and especially sialic acids, are known to play significant roles in interactions and recognition between cells and between cells and viruses (Cohen & Varki, 2010; Raman et al., 2005; Vigerust & Shepherd, 2007). The aim of this thesis was to better understand the roles played by the viral α-2,3-sialyltransferase in the pathogenesis of myxomatosis. Using the Lausanne strain as parental strain, we have constructed strains deficient for the M138L gene encoding the α-2,3-sialyltransferase, and a revertant strain. Although no difference could be detected between the strains in vitro, the M138L knockout strains were highly attenuated in vivo. Especially, we observed more neutrophils at the beginning of infection and then an important mononuclear cells infiltrate in the dermis of the primary sites of infection for rabbits infected with the M138L knockout strains. We then wanted to determine which viral and / or cellular proteins were affected by the viral α-2,3-sialyltransferase, to check if their modification could explain the phenotype that we observed. We showed that the viral M-T7 protein was sialylated by the viral enzyme. M-T7 is a homologue of the interferon-γ receptor (Mossman et al., 1995) which is also able to bind and inhibit several chemokines, to block the chemokine gradient formation and to inhibit the inflammatory cells attraction towards the site of infection (Alcami, 2003; Lalani et al., 1997). However, we could not detect any effect of sialylation on the secretion or the activity of the M-T7 proteins purified from the four strains, either in vitro or in vivo. Altogether , these results show that the viral α-2,3-sialyltransferase is a virulence factor of the virus that could act directly or indirectly on several immunomodulatory viral proteins, and so on the immune cells attraction and adaptive immunity development. [less ▲]

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See detailEtude des sémiochimiques volatils impliqués dans le mutualisme fourmis-pucerons
Fischer, Christophe ULg

Doctoral thesis (2016)

For decades, the mutualistic relationship that ant and aphids may present has fascinated entomologists, as evidenced by the abundant literature on the subject. The principles of this interaction are ... [more ▼]

For decades, the mutualistic relationship that ant and aphids may present has fascinated entomologists, as evidenced by the abundant literature on the subject. The principles of this interaction are simple: as long as their colony remains, aphids provide ants with a stable and abundant source of sugars, honeydew. In exchange, ants tend aphid colonies and provide them cleaning and protection against various natural enemies. Nevertheless, some aspects of this relationship remain misunderstood. This is for example the case of the factors influencing the search and the discovery of a potential partner, first step to any potential mutualistic interaction. The role held by volatile chemical cues, called semiochemicals, in this relationship is also misunderstood. The objective of this thesis is to improve understanding of the role played by volatile semiochemicals in this mutualistic relationship, especially during the partner search stage, both from the perspective of the ant and of the aphid. The black garden ant, Lasius niger L., and the black bean aphid, Aphis fabae Scop., constitute our biological model. The impact of volatile compounds on the search behavior of the ant has first been investigated. These compounds are from multiple origins, either directly emitted by the aphid or induced by its presence. First, the ability of ants to perceive E-β-farnesene, the main component of many aphid alarm pheromone, and to use it to locate aphid colonies has been highlighted. This compound has indeed shown attractiveness to ants, even at low doses corresponding to the emissions of an unstressed aphid colony. Then, the roles played by honeydew volatile compounds in ant attraction have been demonstrated. These compounds also allow ants to remotely discriminate different aphid species and to direct their searches accordingly. These semiochemicals are produced by honeydew microflora, and a particularly attractive bacterial strain, Staphylococcus xylosus, has been isolated from A. fabae honeydew. Finally, the active role of winged aphids, which are aphid’s dispersal form, in the search for a mutualistic partner was also studied. Aphids do not appear to be preferentially attracted toward a host plant frequented by ants or close an ant nest. Nevertheless, once a potential host plant reached, they remain longer on it in case of ant presence. This thesis highlights the importance of volatile semiochemicals and honeydew microflora in ant-aphid mutualistic relationships, thus completing by a new aspect an already well documented biological model. [less ▲]

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See detailAgeism in Belgium and Burundi: A comparative analysis
Marquet, Manon ULg; Missotten, Pierre ULg; Schroyen, Sarah ULg et al

in Clinical Interventions in Aging (2016), 11

Background: Recent cross-cultural comparisons between Asian and Western cultures have shown that ageism arises more from the lack of availability of social and economic resources for older adults than ... [more ▼]

Background: Recent cross-cultural comparisons between Asian and Western cultures have shown that ageism arises more from the lack of availability of social and economic resources for older adults than from the culture itself. We tested this assumption by conducting a survey among people living in a least-developed country compared with a developed country. Methods: Twenty-seven Belgians living in Belgium, 29 Burundians living in Belgium and 32 Burundians living in Burundi were included in this study. Their attitudes toward older adults were assessed using several self-reported measures. Results: Statistical analyses confirmed that older people are more negatively perceived by Burundians living in Burundi than by Burundians and Belgians living in Belgium, whose attitudes did not differ from each other. Conclusion: Consistent with our hypothesis, our results suggest that the level of development of a country and more particularly the lack of government spending on older people (pension and healthcare systems) may contribute to their younger counterparts perceiving them more negatively. [less ▲]

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See detailMESURES INCITATIVES A LA PRODUCTION COTONNIERE ET PERSPECTIVES DE LA PRIVATISATION DES FILIALES CMDT AU MALI
Koné, Bouréma ULg

Doctoral thesis (2016)

Cotton is the first export crop in Mali with 84,370 billion Fcfa in 2010 (INSTAT, 2010), but the production of this crop has huge problems due to external factors (prices of inputs and seed cotton) and ... [more ▼]

Cotton is the first export crop in Mali with 84,370 billion Fcfa in 2010 (INSTAT, 2010), but the production of this crop has huge problems due to external factors (prices of inputs and seed cotton) and internal (within payment to producers, internal debts of cooperatives). To boost cotton production during the years 2010/11 and 2011/12, the government had maintained the level of fertilizer subsidy at 50% of normal price on the market. In addition to this level of subsidy, the incentive price of 255Fcfa / kg was fixed to the producer and the National Union of Cotton Producers Cooperative Societies (NU-CPCS) facilitated the clearance of the internal debts of cooperatives. Despite the fall in world prices after 2011/12, the price of cotton seed remains little changed. The price stayed at 255 CFA francs / kg in 2012/13 and got back to 250 CFA francs / kg in 2013/14. The objective of this work is to analyze the effects of incentives factors cotton production with a view to the privatization of CMDT subsidiaries Surveys were conducted with a sample of 240 farms selected from the four zones of the CMDT zones based on two villages subsidiary during the years of 2008/09, 2010/11 and 2011/12. The results showed a positive trend in production (mainly due to an increase in the area) and in the income of cotton producers with a higher reimbursement rate of input credits under cultivation. The analysis of the Domestic Resource Cost (DRC) the Nominal protection coefficients (NPC) and the Effective (CPE) showed an improvement in thèse variables in 2011/12 with the incentive policy. An analysis of the determinants of the supply of cotton showed that only two variables were significant: the price cottonseed and payment period. The incentive factors are influenced by fiber market in 2011/12 which took a downward trend from the campaign. This incentive policy being favored by the market of fiber which is very unstable, it would be necessary to create conditions in which the producer can benefit from the price obtained on the quality of fiber to maintain the incentive policy for producers. For the privatization of Cotton Company, an upgrade of this company is necessary with the support of the Malian state. But this upgrade should not affect too much the selling price of sale of cotton that can bring new companies in a situation of too long term recovery of capital invested (long period of investment recovery). The privatization scheme as presented makes major companies more competitive. In order to reduce the operating costs a form of collaborative relationships among delivery companies would be required. Keywords: fertilizer subsidy, incentive price, cotton sector in Mali, privatization subsidiary, competitiveness. [less ▲]

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See detailOverhanging Constraints in Addivitive Manufacturing Using Two Different Tools
Bauduin, Simon ULg; Collet, Maxime ULg; Duysinx, Pierre ULg

Poster (2016, August 23)

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount ... [more ▼]

Topology optimization is widely used as a design tool for advanced application in mechanical, aerospace and automotive industries. This technique offers an optimal distribution of a predetermined amount of material in a given design space. In the last years, a lot of efforts has been invested into the development of high performance methods such as homogenization, SIMP or BESO. However as the state of the art in manufacturing experiences evolution, a coupling between topology optimization and additive manufacturing is needed. Additive manufacturing has numerous advantages that fits the characteristics of topology optimized designs. It can manufacture highly complex design without high cost increase and furthermore continuous density material of the SIMP method could be manufactured by lattice structures. With all the opportunities given by the additive manufacturing the urge to bind the last one to topology optimization is heavily required. Specific constraints related to manufacturing issues have to be taken into account such as the need of supports structures to ensure a good heat evacuation during the manufacturing process, as well as to hold up overhanging section. Some researches have been done to try to include this constraint in the optimization problem such as Leary and al or Andrew T. Gaynor. However this work focuses on 2 different methods (projection scheme and mechanical approach) to tackle the overhanging problem and compare them . [less ▲]

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See detailGraphene-multiferroic interfaces for spintronics applications
Zanolli, Zeila ULg

in Scientific Reports (2016)

Graphene and magnetoelectric multiferroics are promising materials for spintronic devices with high performance and low energy consumption. A very long spin di usion length and high carrier mobility make ... [more ▼]

Graphene and magnetoelectric multiferroics are promising materials for spintronic devices with high performance and low energy consumption. A very long spin di usion length and high carrier mobility make graphene attractive for spintronics. The coupling between ferroelectricity and magnetism, which characterises magnetoelectrics, opens the way towards unique device architectures. In this work, we combine the features of both materials by investigating the interface between graphene and BaMnO3, a magnetoelectric multiferroic. We show that electron charge is transferred across the interface and magnetization is induced in the graphene sheet due to the strong interaction between C and Mn. Depending on the relative orientation of graphene and BaMnO3, a quasi-half-metal or a magnetic semiconductor can be obtained. A remarkably large proximity induced spin splitting of the Dirac cones (~300 meV) is achieved. We also show how doping with acceptors can make the high-mobility region of the electronic bands experimentally accessible. This suggests a series of possible applications in spintronics (e.g. spin filters, spin injectors) for hybrid organic-multiferroic materials and reveals hybrid organic-multiferroics as a new class of materials that may exhibit exotic phenomena such as the quantum anomalous Hall effect and a Rashba spin-orbit induced topological gap. [less ▲]

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See detailSO(10) models with flavour symmetries: Classification and examples
Ivanov, Igor ULg; Lavoura, Luis

in Journal of Physics : G Nuclear & Particle Physics (2016), 43(10), 105005

Renormalizable SO(10) grand unified theory (GUT) models equipped with flavour symmetries are a popular framework for addressing the flavour puzzle. Usually, the flavour symmetry group has been an ad hoc ... [more ▼]

Renormalizable SO(10) grand unified theory (GUT) models equipped with flavour symmetries are a popular framework for addressing the flavour puzzle. Usually, the flavour symmetry group has been an ad hoc choice, and no general arguments limiting this choice were known. In this paper, we establish the full list of flavour symmetry groups which may be enforced, without producing any further accidental symmetry, on the Yukawa-coupling matrices of an SO(10) GUT with arbitrary numbers of scalar multiplets in the ${\bf{10}}$, $\bar{{\bf{126}}}$, and ${\bf{120}}$ representations of SO(10). For each of the possible discrete non-Abelian symmetry groups, we present examples of minimal models which do not run into obvious contradiction with the phenomenological fermion masses and mixings. [less ▲]

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See detailLa santé psycho-sociale des adolescents à l’épreuve de l’immigration : le cas des jeunes d’origine marocaine et turque en Belgique.
Gavray, Claire ULg

Conference (2016, August 23)

Cette communication s’appuie sur les analyses effectuées au départ des données belges de l’enquête ‘International Study on Self-reported Delinquency’. Nous investiguons la question du mal-être ... [more ▼]

Cette communication s’appuie sur les analyses effectuées au départ des données belges de l’enquête ‘International Study on Self-reported Delinquency’. Nous investiguons la question du mal-être psychologique desadolescents autochtones et allochtones (via échelle réduite de dépression des adolescents de Moos) encomparaison et en lien avec leur contexte social, affectif et relationnel. Nous affinons l’analyse en ce qui concerne les jeunes d’origine turque et marocaine vivant en Belgique, sachant que si les deux sous-groupes nationaux partagent de nombreuses expériences dans leurs relations aux différentes sphères sociales, leur groupe d’origine se caractérise aussi par des stratégies économiques et d’insertion qui peuvent différer. Nous discutons le résultat selon lequel, malgré un contexte social et historique plus favorable, les jeunes d’origine belge manifestent une tendance dépressive plus prononcée que les autres et la conclusion selon laquelle ce n’est pas automatiquement et exactement les mêmes facteurs socio-relationnels qui expliquent le niveau de dépression dans chacun des groupes étudiés. [less ▲]

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See detailThe influence of background noise on vocal loading parameters in music theory teachers
Schiller, Isabel ULg; Morsomme, Dominique ULg; Sfez, Lou et al

Poster (2016, August 23)

Background: Music theory teachers, who teach rhythm, singing and other music-related skills and topics, depend greatly on a well-functioning voice. Unlike other schoolteachers, who primarily use their ... [more ▼]

Background: Music theory teachers, who teach rhythm, singing and other music-related skills and topics, depend greatly on a well-functioning voice. Unlike other schoolteachers, who primarily use their voice as a pedagogic tool, music theory teachers also use it as an instrument. Furthermore, they often engage in vocally demanding free-time activities requiring a singing voice. To date, few studies have specifically looked at the voice use of music theory teachers. This study aims (1) to measure the background noise level and the amount of vocal loading affecting this specific population, and (2) to describe the influence of background noise on vocal loading parameters. Methods: Thirteen French-speaking music theory teachers (9 females and 4 males) working in a music school were monitored for one workweek, using the VoxLog voice dosimeter (Sonvox). To investigate the professional and extra-professional environments, all subjects wore the dosimeter from early morning until the end of the day. The parameters analysed were background noise level, duration of phonation, sound pressure level (SPL) and fundamental frequency (F0) of voice. Results: Overall, the mean background noise level was 75.2 dB (SD=5.4). We measured higher background noise level at work (mean=78.2 dB, SD=5.8) than in the extra-professional environment (mean=72.2 dB, SD=5.2). As expected, a rise in background noise was accompanied by a significant rise in voice SPL in both males and females (r=.61, p<.001). A significant correlation between background noise and F0 was found in females (r=.41, p=.002), but not in males (r=.39, p=.055). Furthermore, our data exhibit a significant correlation between background noise and duration of phonation (r=.05, p<.001). Conclusion: Our data suggest, that in class, music theory teachers must cope with background noise levels that dramatically exceed the limit of 35 dB recommended by the WHO (Inserm, 2006). High background noise levels lead to an increase in voice SPL, a phenomenon known as the Lombard effect (Inserm, 2006). In female subjects, we also observed a rise in F0 further to high background noise. Like Ternström, Södersten, and Bohman’s (2002) study, our data indicate that high background noise levels increase the duration of phonation. In a noisy environment, subjects seem to prolong the voiced segments of speech to make themselves understood. In other words, high background noise levels result in higher vocal loading. In the long run, this may increase the risk of voice disorders such as hyperfunctional dysphonia or vocal fold pathologies consecutive to repeated microtrauma in music theory teachers. [less ▲]

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See detailLa gestion de la matière organique du sol, un enjeu important pour limiter la lixiviation du nitrate vers les eaux souterraines
Vandenberghe, Christophe ULg; Colinet, Gilles ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment (2016), 21

Description of the subject. The nitrate concentration in half of the groundwater bodies of the Walloon Region (Belgium) has justified their classification as vulnerable zones under the Nitrates Directive ... [more ▼]

Description of the subject. The nitrate concentration in half of the groundwater bodies of the Walloon Region (Belgium) has justified their classification as vulnerable zones under the Nitrates Directive (ND). This vulnerable area has a relatively high diversity of agro-soil environments. Thus, the nitrogen content of agricultural soils can vary locally by a factor 4. Objectives. This study aimed to establish whether the carbon content of a soil is a significant risk factor in nitrate leaching to groundwater. Method. The article is based on measurements of nitrate nitrogen residue (APL) and soil total organic carbon (TOC) at the beginning of the leaching period. The measurements were made in 2012 in 1,500 plots, during inspections organized by the Wallonia Public Service. This was as part of the application of the Program for the Sustainable Management of Nitrogen in Agriculture, the scheme for implementing the ND within the Walloon region. Results. Examination of the results showed both that the APL was positively correlated to the TOC and that plots with “noncompliant” APL results had a significantly higher average TOC than the other plots. Conclusions. Since APL is an environmental indicator of the risk of nitrate leaching, it appears that the TOC may constitute a risk of groundwater contamination by nitrate. It is therefore advisable to improve the inclusion of this parameter in advice regarding nitrogen fertilization and secondly, in the case of summer harvest, to better manage the sowing of catch crops. [less ▲]

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See detailOccurrence rates of invasive plants in limestone quarries (Southern Belgium)
Pitz, Carline ULg; Jorion, Alexis ULg; Mahy, Grégory ULg et al

Conference (2016, August 23)

In quarries, invasive plant species can slow down the installation of high conservation value vegetation. Successful management of invasive requires, at first, a quantitative assessment of invasion levels ... [more ▼]

In quarries, invasive plant species can slow down the installation of high conservation value vegetation. Successful management of invasive requires, at first, a quantitative assessment of invasion levels. Although European legislation has adopted an ambitious strategy against invasive species, there is still a lack of knowledge about their occurrence in quarries. The aim of this study was to evaluate occurrence rates of invasive plant species in limestone quarries throughout Wallonia (Southern Belgium) and identify high priority and emerging invasive plants for adapted management. During 2016 vegetation period, forty quarries were selected by stratified sampling, using abandoned and active quarries as strata. Within selected quarries, two-meter wide transects were established to cross all activity sectors. Transects were divided in 10x2m plots, resulting in 2% of total surface of each quarry being surveyed. Cover and number of individuals of invasive plants species were recorded in each plot. Species considered were those of Harmonia list (67 species), the reference at the Wallonia scale. More than 30 000 plots were surveyed. Results of our recent study are presented (occurrences rates by species, mean percentage cover per site). First results indicate that dominant invasive species originate from different introduction paths: (i) planted (Robinia pseudoacacia); (ii) ornamentals (Cotoneaster horizontalis) and (iii) spontaneous colonization (Senecio inaequidens) - and follow various invasion dynamics. We propose research and management methods to be directed towards limitation of top ten frequent species (e.g. Buddleia davidii, Senecio inaequidens), and to establish a detection system for the emerging invasive plants. [less ▲]

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See detailDevelopment of innovative and practical management tools to improve sustainability of milk production and quality of dairy products
Arnould, Valérie ULg

Doctoral thesis (2016)

In the current complex economical context, novel strategies are needed to help local dairy farmers to face the European dairy sector crisis. This thesis was initiated in the framework of ManageMilk ... [more ▼]

In the current complex economical context, novel strategies are needed to help local dairy farmers to face the European dairy sector crisis. This thesis was initiated in the framework of ManageMilk project and was globally aimed to investigate the possibility to develop some innovative and practical management tools helping dairy farmers in their daily decisions. To develop such management tools, several conditions must be fulfilled. Firstly, used data must be relevant. According to the literature, the milk composition, and in particular, the milk fatty acid (FA) profile, appears to be a suitable trait allowing useful information about the dairy cow’s health status or about the management system efficiency. These data must also be easily available at low cost from milk recording organization. Recently, the MIR spectrometry offers the possibility to build routinely cheaper and more important databases. To develop management tools, milk samples have to be collected using comparable sampling methods. Unfortunately, in order to decrease the milk quality control costs, the International Committee for Animal Recording allows alternative sampling schemes including the collection of samples from morning or evening only milkings. This alternative sampling scheme can interact with phenotypic and genetic parameters. Therefore, additionally to the development of conversion equations, this thesis is establishing if morning or evening only milkings are genetically different traits. Last condition concerns a useful phenotypic and genetic variability. Milk FA profile is, among others, altered by genetics. So, one paper of this thesis concerns the setup of a useful genetic evaluation model able to estimate accurately the genetic part of milk fat composition variations. Routine genetic evaluation of production traits in dairy cattle commonly uses random regression model (RRM). Recently, “splines” have been advocated as a good alternative to Legendre polynomials (LP) for analyzing test-day yields in RRM. Therefore, several models are compared. Obtained results show the possibility to propose a practical and robust method for estimating accurate daily major FA production from single milking, useful for a further development of practical management tools helping dairy farmers in their daily decisions. [less ▲]

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See detailO acontecimento enunciativo na semiótica da imagem
Dondero, Maria Giulia ULg; Colas-Blaise, Marion

in Mendes, Conrado; Muniz, Glaucia (Eds.) Em torno do acontecimento: uma homenagem a Claude Zilberberg (2016)

Dans cet article, nous visons à montrer que la sémiotique tensive développée par Zilberberg permet de revisiter utilement les notions barthésiennes de studium et de punctum et, de surcroît, de devenir un ... [more ▼]

Dans cet article, nous visons à montrer que la sémiotique tensive développée par Zilberberg permet de revisiter utilement les notions barthésiennes de studium et de punctum et, de surcroît, de devenir un outil pour l’analyse de l’image. Dans un premier temps, nous reprenons les notions de studium et de punctum dans le cadre d’une théorie de la photographie, en mettant également en valeur la manière dont Shairi & Fontanille (2001) enrichissent l’opposition entre studium et punctum à travers la gradualité des différentes positions énonciatives garanties par le tempo. Dans un deuxième temps, nous mettons la théorie barthésienne en regard avec la théorie zilberberghienne, ce qui nous amènera à l’analyse de quelques œuvres de Paul Klee et à considérer le punctum et l’événement de Zilberberg comme des effets de la composition énonciative au sein du médium pictural. [less ▲]

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See detailPassive Linearization of Nonlinear System Resonances
Habib, Giuseppe ULg; Grappasonni, Chiara ULg; Kerschen, Gaëtan ULg

Conference (2016, August 22)

In this work we demonstrate that the addition of properly-tuned nonlinearities to a nonlinear system can increase the range over which a specific resonance responds linearly. Specifically, we seek to ... [more ▼]

In this work we demonstrate that the addition of properly-tuned nonlinearities to a nonlinear system can increase the range over which a specific resonance responds linearly. Specifically, we seek to enforce two important properties of linear systems, namely the force-displacement proportionality and the invariance of resonance frequencies. Theoretical findings are validated through numerical simulations and experiments. [less ▲]

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See detailAIRE polymorphism, melanoma antigen-specific T cell immunity, and susceptibility to melanoma
Conteduca, Giuseppina ULg

in Oncotarget (2016)

AIRE is involved in susceptibility to melanoma perhaps regulating T cell immunity against melanoma antigens (MA). To address this issue, AIRE and MAGEB2 expressions were measured by real time PCR in ... [more ▼]

AIRE is involved in susceptibility to melanoma perhaps regulating T cell immunity against melanoma antigens (MA). To address this issue, AIRE and MAGEB2 expressions were measured by real time PCR in medullary thymic epithelial cells (mTECs) from two strains of C57BL/6 mice bearing either T or C allelic variant of the rs1800522 AIRE SNP. Moreover, the extent of apoptosis induced by mTECs in MAGEB2-specific T cells and the susceptibility to in vivo melanoma B16F10 cell challenge were compared in the two mouse strains. The C allelic variant, protective in humans against melanoma, induced lower AIRE and MAGEB2 expression in C57BL/6 mouse mTECs than the T allele. Moreover, mTECs expressing the C allelic variant induced lower extent of apoptosis in MAGEB2-specific syngeneic T cells than mTECs bearing the T allelic variant (p < 0.05). Vaccination against MAGEB2 induced higher frequency of MAGEB2-specific CTL and exerted higher protective effect against melanoma development in mice bearing the CC AIRE genotype than in those bearing the TT one (p < 0.05). These findings show that allelic variants of one AIRE SNP may differentially shape the MA-specific T cell repertoire potentially influencing susceptibility to melanoma. [less ▲]

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See detailNew role of osteopontin in DNA repair and impact on human glioblastoma radiosensitivity
Henry, Aurélie ULg; Nokin, Marie-Julie ULg; Leroi, Natacha ULg et al

in Oncotarget (2016)

Glioblastoma (GBM) represents the most aggressive and common solid human brain tumor. We have recently demonstrated the importance of osteopontin (OPN) in the acquisition/maintenance of stemness ... [more ▼]

Glioblastoma (GBM) represents the most aggressive and common solid human brain tumor. We have recently demonstrated the importance of osteopontin (OPN) in the acquisition/maintenance of stemness characters and tumorigenicity of glioma initiating cells. Consultation of publicly available TCGA database indicated that high OPN expression correlated with poor survival in GBM patients. In this study, we explored the role of OPN in GBM radioresistance using an OPN-depletion strategy in U87-MG, U87-MG vIII and U251-MG human GBM cell lines. Clonogenic experiments showed that OPN-depleted GBM cells were sensitized to irradiation. In comet assays, these cells displayed higher amounts of unrepaired DNA fragments post-irradiation when compared to control. We next evaluated the phosphorylation of key markers of DNA double-strand break repair pathway. Activating phosphorylation of H2AX, ATM and 53BP1 was signi cantly decreased in OPN-de cient cells. The addition of recombinant OPN prior to irradiation rescued phospho-H2AX foci formation thus establishing a new link between DNA repair and OPN expression in GBM cells. Finally, OPN knockdown improved mice survival and induced a signi cant reduction of heterotopic human GBM xenograft when combined with radiotherapy. This study reveals a new function of OPN in DNA damage repair process post-irradiation thus further con rming its major role in GBM aggressive disease. [less ▲]

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See detailANALYSE DE LA DEMANDE EN CHARBON DE BOIS PAR LES MÉNAGES URBAINS DE BUJUMBURA AU BURUNDI
Sabuhungu, Emery Gaspard ULg

Doctoral thesis (2016)

The objective of this study is to evaluate the demand for charcoal by urban households in Bujumbura in order to make recommendations ensuring the security of household energy and environmental protection ... [more ▼]

The objective of this study is to evaluate the demand for charcoal by urban households in Bujumbura in order to make recommendations ensuring the security of household energy and environmental protection. To achieve this objective, the analysis of the related documentation and collection of secondary data were carried out in order to formulate specific objectives, hypotheses and the methodology used in the course of this study. The specific objectives are: to analyze the structure, operation and market performance of the charcoal market in the city of Bujumbura and to compare this market to the cities of Lubumbashi and Kigali; to determine the charcoal consumption pattern by urban households in Bujumbura; to identify the factors which influence the demand for charcoal by urban households in Bujumbura; to evaluate the demand for charcoal by urban households in Bujumbura. The assumptions made in this study are: the charcoal market in the city of Bujumbura is a competitive and effective market; charcoal is the dominating cooking fuel used by urban households in Bujumbura and is consumed exclusively or in combination with others; an urban household’s demand for charcoal in Bujumbura is essentially based on household income, the size of household, eating habits (preparation of food that requires a long cooking time), the frequency of use of carbon and the possession or not of improved cooking stoves; the demand for charcoal by urban households in Bujumbura is high and this leads to significant annual deforestation. Three surveys were conducted to collect primary data. The first survey, with the specific objective of analysing the charcoal market in Bujumbura, was conducted among the key players of the charcoal value chain produced in the communes of Mugamba and Muramvya and consumed in the city of Bujumbura. The remaining two surveys, with the specific objective of analysing the consumption of charcoal by households, were conducted among households-users of charcoal of different standards of living in three areas of the city of Bujumbura (areas Buterere, Cibitoke and Rohero). The results indicate that the charcoal market is competitive. The production, the commercialisation and the consumption of charcoal allow the creation of positive value added all along the charcoal value chain. The use of cooking fuels by households in Bujumbura shows that they have not yet achieved an energy transition. In fact, 83% of those surveyed only use charcoal; 12% combine charcoal and electricity and 5% combine charcoal and firewood. The results revealed that the main factors influencing households demand for charcoal are: household income, the price of charcoal, household size, number of cooking sessions per day, frequency of preparation of cassava leaves and the possession or not of improved braziers. To solve the energy and environmental problem, a rehabilitation of woodland, an implementation of the best techniques of woodland planting with the most adaptable species on productive land, a greater penetration of substitutable energy to wood fuel such as gas or electricity, a growth in the use of improved cooking stoves in households and greater efficiency in wood carbonisation will help reduce the number of hectares of deforestation for wood energy needs. [less ▲]

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See detailDesign of microstructures using stress-based topology optimization
Collet, Maxime ULg; Bruggi, Matteo; Noël, Lise ULg et al

Conference (2016, August 22)

This paper aims at designing microstructures using stress-based topology optimization. Most of the developments so far have been made for compliance design in various field of applications as reflected in ... [more ▼]

This paper aims at designing microstructures using stress-based topology optimization. Most of the developments so far have been made for compliance design in various field of applications as reflected in the literature. The emergence of the new additive manufacturing techniques allows to consider porous material, such as lattice structures for instance, which ca be used for the design of structural components subject to various solicitations. Those components must account for the stress level to prevent failure everywhere in the microstructures and by extension the whole structure itself. This work proposes to design such microstructures using topology optimization with limitation on the stress level within the microstructures before printing the result. The homogenization technique is used to determine the equivalent material properties. The issues and perspectives are also discussed. [less ▲]

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