Publications ORBi OA     Results 201-220 of 32194.   6 7 8 9 10 11 12 13 14 15 16   Understanding variable importances in forests of randomized treesLouppe, Gilles ; Wehenkel, Louis ; Sutera, Antonio et alin Advances in Neural Information Processing Systems 26 (2013, December)Despite growing interest and practical use in various scientific areas, variable importances derived from tree-based ensemble methods are not well understood from a theoretical point of view. In this work ... [more ▼]Despite growing interest and practical use in various scientific areas, variable importances derived from tree-based ensemble methods are not well understood from a theoretical point of view. In this work we characterize the Mean Decrease Impurity (MDI) variable importances as measured by an ensemble of totally randomized trees in asymptotic sample and ensemble size conditions. We derive a three-level decomposition of the information jointly provided by all input variables about the output in terms of i) the MDI importance of each input variable, ii) the degree of interaction of a given input variable with the other input variables, iii) the different interaction terms of a given degree. We then show that this MDI importance of a variable is equal to zero if and only if the variable is irrelevant and that the MDI importance of a relevant variable is invariant with respect to the removal or the addition of irrelevant variables. We illustrate these properties on a simple example and discuss how they may change in the case of non-totally randomized trees such as Random Forests and Extra-Trees. [less ▲]Detailed reference viewed: 809 (88 ULg) Tgfbeta-Smad and MAPK signaling mediate scleraxis and proteoglycan expression in heart valves.Barnette, Damien; Hulin, Alexia; Ahmed, Ishtiaq et alin Journal of Molecular and Cellular Cardiology (2013), 65Detailed reference viewed: 9 (0 ULg) Study of the roles of Cyprinid herpesvirus 3 ORF134 in the biology of the infectionOuyang, Ping Doctoral thesis (2013)The common carp is one of the most important freshwater fish species in aquaculture, and its colourful subspecies koi is grown for personal pleasure and competitive exhibitions. Both two subspecies are ... [more ▼]The common carp is one of the most important freshwater fish species in aquaculture, and its colourful subspecies koi is grown for personal pleasure and competitive exhibitions. Both two subspecies are economically important. In the late 1990s, a highly contagious and lethal pathogen called koi herpesvirus (KHV) or cyprinid herpesvirus 3 (CyHV-3) began to cause severe financial losses in these two carp industries worldwide. In 2005, CyHV-3 has been classified in the Alloherpesviridae family of the order Herpesvirales. Because of its economic importance and its numerous original biological properties, CyHV 3 became rapidly an attractive subject for applied and fundamental research. However, to date, there is a little information on the roles of individual CyHV-3 genes in the biology of CyHV-3 infection or its pathogenesis. Moreover, there is a lack of safe and efficacious vaccine for the control of CyHV-3 disease. The goal of this thesis was to study the roles of CyHV-3 ORF134 encoding an IL-10 homologue in the biology of the infection. CyHV-3 ORF134 has been predicted to contain an 84 bp intron flanked by 2 exons encoding together a 179 amino acid product. Transcriptomic analyses reveal that ORF134 is expressed as a spliced early-late gene. The identification of the CyHV-3 secretome was achieved using 2D-LC MS/MS proteomic approach. This method led to the identification of 5 viral and 46 cellular proteins in concentrated infected cell culture supernatant. CyHV-3 ORF12 and ORF134 were amongst the most abundant proteins detected. To investigate the roles of ORF134 in the biological of the infection, a strain deleted for ORF134 and a derived revertant strain were produced by using BAC cloning and prokaryotic recombination technologies. Comparison of these strains demonstrated that CyHV-3 ORF134 does not contribute significantly to viral growth in vitro or to virulence in vivo in the present laboratory setting. The present study addressed for the first time the in vivo role of a vIL-10 encoded by a member of the family Alloherpesviridae. This study has been published in Veterinary Research. During the course of the first study, we obtained an unexpected recombination event while we were reconstituting infectious virus from mutated BAC plasmids. To generate a revertant ORF134 Del galK strain, CCB cells were co-transfected with the FL BAC ORF134 Del galK plasmid and the pGEMT-TK vector to remove the BAC cassette inserted in the ORF55 locus (encoding thymidine kinase). One of the clones obtained had an unexpected recombination leading to the deletion of ORF56 and ORF57 in addition to the expected deletion of ORF134. Unexpectedly, this triple deleted strain replicated efficiently in vitro, exhibited an attenuated phenotype in vivo and was proved to confer in a dose dependent manner an immune protection against a lethal challenge. The goal of the second experimental chapter was to investigate the role of the ORF56-57 and ORF134 deletions in the observed safety/efficacy profile of the triple deleted recombinant. To reach this goal, a collection of recombinant strains were produced using BAC cloning technologies, characterized and tested in vivo for their safety/efficacy profile. The results obtained demonstrated that the ORF56-57 deletion is responsible for the phenotype observed and that ORF134 deletion does not contribute to this phenotype significantly. Finally, the immune protection conferred by ORF56-57 deleted recombinant was investigated by challenging immunized fish with a wild type strain expressing luciferase as a reporter gene. In vivo imaging system (IVIS) analyses of immunized and challenged fish demonstrated that the immune response induced by the ORF56-57 deleted strain was able to prevent subclinical infection of the challenge strain. In conclusion, the present thesis addressed both fundamental and applied aspects of CyHV-3. For the first time, it investigated in vivo the roles of a viral IL-10 homologue encoded by a member of the family Alloherpesviridae. Importantly, it identified the ORF56-57 loci as target for production of safe and efficacious attenuated recombinant vaccines. [less ▲]Detailed reference viewed: 17 (7 ULg) Performances of Volume Phase Holographic grating for space applications: study of the radiation effectLoicq, Jerôme ; Georges, Marc ; Stockman, Yvan et alin Journal of Applied Physics (2013), 52(34), The special properties of volume phase holographic gratings make them promising candidates for spectrometry applications where high spectral resolution, low levels of straylight, and low polarization ... [more ▼]The special properties of volume phase holographic gratings make them promising candidates for spectrometry applications where high spectral resolution, low levels of straylight, and low polarization sensitivity are required. Therefore it is of interest to assess the maturity and suitability of volume phase holographic gratings as enabling technologies for future space missions, with demanding requirements for spectrometry. One of the main areas of research is related to grating ageing under space radiation. In the present paper, two volume grating technologies are analyzed and compared under gamma irradiation. The performances of both technologies, the photo–thermo–refractive glass and the Dichromated Gelatin, are tested on samples and assessed in the and near-infrared bands. The diffraction efficiency degradation under gamma irradiation is assessed. [less ▲]Detailed reference viewed: 12 (3 ULg) FROM SECRET AGENTS TO INTERAGENCYDespret, Vinciane in History and theory (2013), 52Some scientists who study animals have emphasized the need to focus on the “point of view” of the animals they are studying. This methodological shift has led to animals being credited with much more ... [more ▼]Some scientists who study animals have emphasized the need to focus on the “point of view” of the animals they are studying. This methodological shift has led to animals being credited with much more agency than is warranted. However, as critics suggest, on the one hand, the “perspective” of another being rests mostly upon “sympathetic projection,” and may be difficult to apply to unfamiliar beings, such as bees or even flowers. On the other hand, the very notion of agency still conveys its classic understanding as intentional, rational, and premeditated, and is still embedded in humanist and Christian conceptions of human exceptionalism. This paper seeks, in the first part, to investigate the practical link between these two notions and the problems they raise. In the second part, following the work of two historians of science who have revisited Darwin’s studies of orchids and their pollinators, it will observe a shift in the meaning of the concept of agency. Indeed, creatures may appear as “secret agents” as long as we adopt a conventional definition of agency based on subjective experience and autonomous intention. However, when reframed in the terms of “agencement”—an assemblage that produces “agentivity”— agency seems to be much more extensively shared in the living world. We will then explore some of the concrete situations in which these agencements are manifested, and through which creatures of different species become, one for another and one with another, companion-agents. [less ▲]Detailed reference viewed: 9 (0 ULg) Structural characterisation of polyglutamine-inserted BlaP beta-lactamase -- A model for Huntington’s disease and related neurological disordersKay, Jennifer Poster (2013, December)Detailed reference viewed: 9 (0 ULg) Quadratization of symmetric pseudo-Boolean functionsAnthony, Martin; Boros, Endre; Crama, Yves et alE-print/Working paper (2013)A pseudo-Boolean function is a real-valued function $f(x)=f(x_1,x_2,\ldots,x_n)$ of $n$ binary variables; that is, a mapping from $\{0,1\}^n$ to ${\bbr}$. For a pseudo-Boolean function $f(x)$ on $\{0,1 ... [more ▼]A pseudo-Boolean function is a real-valued function$f(x)=f(x_1,x_2,\ldots,x_n)$of$n$binary variables; that is, a mapping from$\{0,1\}^n$to${\bbr}$. For a pseudo-Boolean function$f(x)$on$\{0,1\}^n$, we say that$g(x,y)$is a quadratization of$f$if$g(x,y)$is a quadratic polynomial depending on$x$and on$m$auxiliary binary variables$y_1,y_2,\ldots,y_m$such that$f(x)= \min \{ g(x,y) : y \in \{0,1\}^m \} $for all$x \in \{0,1\}^n$. By means of quadratizations, minimization of$f$is reduced to minimization (over its extended set of variables) of the quadratic function$g(x,y)$. This is of some practical interest because minimization of quadratic functions has been thoroughly studied for the last few decades, and much progress has been made in solving such problems exactly or heuristically. A related paper initiated a systematic study of the minimum number of auxiliary$y$-variables required in a quadratization of an arbitrary function$f$(a natural question, since the complexity of minimizing the quadratic function$g(x,y)$depends, among other factors, on the number of binary variables). In this paper, we determine more precisely the number of auxiliary variables required by quadratizations of \emph{symmetric} pseudo-Boolean functions$f(x)$, those functions whose value depends only on the Hamming weight of the input$x\$ (the number of variables equal to 1). [less ▲]Detailed reference viewed: 11 (1 ULg) Developing a Global Food Security PolicyPaveliuc Olariu, Codrin in Advances in Agriculture & Botanics (2013), 5(3), 169-173The world agrifood system continues to be in a vulnerable state as we fast approach the 2015 deadline for the Millennium Development Goal of halving the proportion of people suffering from hunger ... [more ▼]The world agrifood system continues to be in a vulnerable state as we fast approach the 2015 deadline for the Millennium Development Goal of halving the proportion of people suffering from hunger. Although a number of countries have made important changes towards developing food related policies, at the level of the global community, the challenge of food (in)security has not been able push policy makers to develop a common solution to be applied, solution that could include the regional and national specificities registered around the world, while also integrating a global view of increasing agricultural productivity, higher farm competitiveness and without relinquishing the national or individual right for food governance. [less ▲]Detailed reference viewed: 8 (2 ULg) Food scarcity as a trigger for civil unrestPaveliuc Olariu, Codrin in Advances in Agriculture & Botanics (2013), 5(3), 174-178Throughout history, there have been periods of civil unrest. From religious wars to wars of conquest, historians believe that the causes of wars are closely related with religious, political or economic ... [more ▼]Throughout history, there have been periods of civil unrest. From religious wars to wars of conquest, historians believe that the causes of wars are closely related with religious, political or economic reasons. But when we discuss about civil unrest inside a country with the power of transforming it into a civil war and expanding at regional level, the triggering factors have yet to be discovered. From the period of the Qing Dinasty (1644-1911) in China to the Great Depression in the 1930s in the USA or the beginning of the second World War in France, these periods have two common points: civil unrest and food shortages. [less ▲]Detailed reference viewed: 10 (0 ULg) Model Predictive Control of Voltages in Active Distribution NetworksValverde Mora, Gustavo ; Van Cutsem, Thierry in IEEE Transactions on Smart Grid (2013), 4(4), 2152-2161This paper presents a centralized control scheme to regulate distribution network voltages in the presence of high penetration of distributed generation. The approach is inspired of Model Predictive ... [more ▼]This paper presents a centralized control scheme to regulate distribution network voltages in the presence of high penetration of distributed generation. The approach is inspired of Model Predictive Control in order to compensate for modeling inaccuracies and measurement noise. The control actions, calculated from a multi-step optimization, are updated and corrected by real-time measurements. The proposed controller uses a linear model to predict the behavior of the system and the optimization is solved using quadratic programming. The proposed corrective control has been tested in a 11-kV distribution network including 75 nodes and hosting 22 distributed generating units. [less ▲]Detailed reference viewed: 256 (59 ULg) The underestimation of seagrass biological cycle in the biomonitoring of coastal trace element pollutionRichir, Jonathan ; Sartoretto, Stéphane; Gobert, Sylvie Poster (2013, December)Previous monitoring surveys using the Mediterranean seagrass Posidonia oceanica (L.) Delile mostly studied coastal pollutions in Cr, Ni, Cu, Zn, Cd, Pb and/or Fe and the distribution of their ... [more ▼]Previous monitoring surveys using the Mediterranean seagrass Posidonia oceanica (L.) Delile mostly studied coastal pollutions in Cr, Ni, Cu, Zn, Cd, Pb and/or Fe and the distribution of their bioaccumulated levels between the seagrass compartments. In contrast, other trace elements (TEs) like As, V, Ag, Be, Al, Mn, Co, Se, Mo, Sn, Sb and Bi, many of them categorized as TEs of environmental emerging concern, have been subject to nearly no ecotoxicological survey with that species. Moreover, the understanding of the seasonal variation of TE levels according to the seagrass biological cycle, a prerequisite to the intercomparison of sites sampled at different periods of the year, has been little investigated. P. oceanica were thus seasonally collected for TE analyses from March 2008 to November 2010 in the Calvi Bay (Corsica, France), a reference site for the northwestern Mediterranean, and near the sewer outfall of Marseille city (France). Results showed that levels of the 19 studied TEs evolved seasonally according to the seagrass biological cycle. So, foliar levels of Cr, Pb, Mn or Bi, preferentially accumulated in older leaves, increased from spring to autumn, as the number of adult leaves. V, Se, As or Sb evolved similarly to the shoot foliar surface, reflecting the plant growth. Cu levels, an essential micronutrient, were lower when summer requirements for leaf growth were high. Al foliar levels evolved similarly to rhizome and root levels, resulting from its acropetal translocation. However, in the anthropized Marseille site, environmental variables non-intrinsic to the seagrass ecophysiology could perturb this seasonal variation. This survey allowed highlighting the proportionally equivalent roles played by both the seagrass biological cycle and its environment in the bioaccumulation process of TEs. This cyclic evolution should therefore be systematically quantified in regional reference sites in order to properly intercompare results from biomonitoring surveys. [less ▲]Detailed reference viewed: 5 (0 ULg) Transiting planets from WASP-South, Euler and TRAPPIST: WASP-68 b, WASP-73 b and WASP-88 b, three hot Jupiters transiting evolved solar-type starsDelrez, Laetitia ; Van Grootel, Valérie ; Anderson, D. R. et alE-print/Working paper (2013)We report the discovery by the WASP transit survey of three new hot Jupiters, WASP-68 b, WASP-73 b and WASP-88 b. WASP-68 b has a mass of 0.95+-0.03 M_Jup, a radius of 1.24-0.06+0.10 R_Jup, and orbits a V ... [more ▼]We report the discovery by the WASP transit survey of three new hot Jupiters, WASP-68 b, WASP-73 b and WASP-88 b. WASP-68 b has a mass of 0.95+-0.03 M_Jup, a radius of 1.24-0.06+0.10 R_Jup, and orbits a V=10.7 G0-type star (1.24+-0.03 M_sun, 1.69-0.06+0.11 R_sun, T_eff=5911+-60 K) with a period of 5.084298+-0.000015 days. Its size is typical of hot Jupiters with similar masses. WASP-73 b is significantly more massive (1.88-0.06+0.07 M_Jup) and slightly larger (1.16-0.08+0.12 R_Jup) than Jupiter. It orbits a V=10.5 F9-type star (1.34-0.04+0.05 M_sun, 2.07-0.08+0.19 R_sun, T_eff=6036+-120 K) every 4.08722+-0.00022 days. Despite its high irradiation (2.3 10^9 erg s^-1 cm^-2), WASP-73 b has a high mean density (1.20-0.30+0.26 \rho_Jup) that suggests an enrichment of the planet in heavy elements. WASP-88 b is a 0.56+-0.08 M_Jup planet orbiting a V=11.4 F6-type star (1.45+-0.05 M_sun, 2.08-0.06+0.12 R_sun, T_eff=6431+-130 K) with a period of 4.954000+-0.000019 days. With a radius of 1.70-0.07+0.13 R_Jup, it joins the handful of planets with super-inflated radii. The ranges of ages we determine through stellar evolution modeling are 4.2-8.3 Gyr for WASP-68, 2.7-6.4 Gyr for WASP-73 and 1.8-5.3 Gyr for WASP-88. WASP-73 appears to be a significantly evolved star, close to or already in the subgiant phase. WASP-68 and WASP-88 are less evolved, although in an advanced stage of core H-burning. [less ▲]Detailed reference viewed: 2 (0 ULg) Tiens ?? Une pièce en wallon au Théâtre de Liège...Baiwir, Esther Article for general public (2013)En décembre, le nouveau Théâtre de Liège propose à son public de découvrir une œuvre en wallon, Lès vwès dèl nut' , de Jean Rathmès. Si cet auteur mérite certainement l'hommage qui lui est ainsi rendu, c ... [more ▼]En décembre, le nouveau Théâtre de Liège propose à son public de découvrir une œuvre en wallon, Lès vwès dèl nut' , de Jean Rathmès. Si cet auteur mérite certainement l'hommage qui lui est ainsi rendu, c'est aussi l'occasion de s'interroger sur le sens de mettre en scène du théâtre dialectal aujourd'hui. [less ▲]Detailed reference viewed: 16 (2 ULg) Construction et stratégies identitaires de francophones en Flandre et de néerlandophones en Wallonie : Fondements théoriquesDassargues, Alix Conference (2013, November 29)Detailed reference viewed: 11 (0 ULg) l'amour à l'épreuve des sociétés - pourquoi l'amour fait mal ?Gavray, Claire Conference given outside the academic context (2013)analyse des évolutions en matière de relations amoureuses (sexualité- engagement-émotion) et des enjeux de genre par rapport à ces évolutions - référence à l'ouvrage de la sociologue E.IllouzDetailed reference viewed: 12 (1 ULg) Emissions d’ammoniac et de gaz à effet de serre associées à l’hébergement de porcs charcutiers et de truies gestantes sur caillebotis et sur litière pailléePhilippe, François-Xavier Doctoral thesis (2013)Detailed reference viewed: 5 (1 ULg) Le Parti Libertarien (PLIB), ou le manifeste du culte de la liberté et de la propriété de soi ?Piet, Grégory E-print/Working paper (2013)Detailed reference viewed: 7 (0 ULg) Bio-based paintsOlive, Gilles ; Richel, Aurore Poster (2013, November 27)Paints, at the coating meaning, are known since a long time. Typically, paint is a dispersion of one or more powders (pigments and fillers) in a macromolecular substance ("resin"), called film-forming ... [more ▼]Paints, at the coating meaning, are known since a long time. Typically, paint is a dispersion of one or more powders (pigments and fillers) in a macromolecular substance ("resin"), called film-forming material, diluted in solvents. [less ▲]Detailed reference viewed: 7 (3 ULg) Old inks: plant-based inksWymeersch, Noémie; Despy, Jessica; Bouchat, Isabelle et alPoster (2013, November 27)Thousands of years ago, natural pigments were discovered and they have been used ever since. Indeed, prehistoric people already used them to paint the walls of the caves in which they were living. A ... [more ▼]Thousands of years ago, natural pigments were discovered and they have been used ever since. Indeed, prehistoric people already used them to paint the walls of the caves in which they were living. A significant example of this is the Cosquer cave (-19,000 to -27,000 years) located near Marseilles (France). Pigments and dyes can be classified into two broad categories: natural pigments and dyes and those called artificial. These categories are then subdivided into five families. The first one of these five families includes the mineral pigments. Among these we can find the clays (yellow ochre, red ochre, green clay, brown clay) and the stones like lapis lazuli (blue) and malachite (green). The second and third families gather the organic dyes and pigments. Those that have vegetal origins like indigo (blue), weld (yellow) and madder (red) compose the family 2 and those that have animal origins like cochineal (red) and kermes dyers (carmine) form the family 3. One family includes pigments and dyes stemming from chemical reactions such as verdigris or red lead (family 4) and the other one is made of the miscellaneous inks such as iron-gall type who are vegetal and mineral one (family 5). All these pigments, although they have been used for centuries, have been replaced by synthetic dyes from the oil industry at the end of the 19th century. Indeed, they have the advantage of reproducibility of the properties unlike natural pigments. But the scarcity of oil causes a renewed interest in natural preparations. In such purpose, our laboratory in conjunction with the Abbey of Villers-la-Ville has decided to study natural derivatives for inks and focuses in particular on the extraction of pigments from plants. [less ▲]Detailed reference viewed: 10 (3 ULg) Introduction de la conférence inaugurale de J.-P. Bronckart "Dimensions praxéologiques et gnoséologiques de l'organisation des textes/discours" (27/11/2013) et aux deux journées d'études sur les "genres" en Langues et littératures modernes : didactique - linguistique, littérature, traduction (24 et 25 avril 2014)Simons, Germain ; Letawe, Céline Conference (2013, November 27)Cette introduction visait à présenter brièvement a) les objectifs de l'Entité de recherche structurelle du département, b) l'objet de recherche : les "genres", c) le programme des deux journées d'études ... [more ▼]Cette introduction visait à présenter brièvement a) les objectifs de l'Entité de recherche structurelle du département, b) l'objet de recherche : les "genres", c) le programme des deux journées d'études dans les quatre grands domaines de recherche : littérature, linguistique, didactique et traduction et d) l'orateur de cette conférence inaugurale : J.P. Bronckart (Université de Genève). [less ▲]Detailed reference viewed: 6 (0 ULg)