Last 7 days     Results 581-600 of 17297.   25 26 27 28 29 30 31 32 33 34 35   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: 803 (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) Herman Vander Linden (1868-1956). Professeur à l'ULg et historienGenin, Vincent in Académie Royale des Sciences d'Outre-Mer (Ed.) Dictionnaire Biographique des Belges d'Outre-Mer (2013)Detailed reference viewed: 19 (4 ULg) René Clémens (1911-1980). Professeur à l'ULg, juriste et sociologueGenin, Vincent in Académie Royale des Sciences d'Outre-Mer (Ed.) Dictionnaire Biographique des Belges d'Outre-Mer (2013)Detailed reference viewed: 18 (1 ULg) Ferdinand Campus (1894-1983). Professeur à l'ULg/Recteur et ingénieurGenin, Vincent in Académie Royale des Sciences d'Outre-Mer (Ed.) Dictionnaire Biographique des Belges d'Outre-Mer (2013)Detailed reference viewed: 20 (3 ULg) Effects of Parecoxib on The Prevention of Postoperative Peritoneal Adhesions in Rats.Arung, Willy; Jehaes, Francois; Cheramy, Jean-Paul et alin Journal of Investigative Surgery : The Official Journal of the Academy of Surgical Research (2013), 26(6), 340-346ABSTRACT Background: No systemic preventive therapy has been successful in inhibiting the development of postoperative peritoneal adhesions (PPAs). Objective: The aim of this study was to evaluate the ... [more ▼]ABSTRACT Background: No systemic preventive therapy has been successful in inhibiting the development of postoperative peritoneal adhesions (PPAs). Objective: The aim of this study was to evaluate the potential effects of 5 day administration of parecoxib, on PPA prevention and on suture or wound healing in rats. Methods: In a model of PPAs induced by peritoneal electrical burn, 30 rats were randomized into 3 groups according to parecoxib administration route (control; intraperitoneal (IP); intramuscular (IM)). Plasma and peritoneal levels of PAI-1 and tPA were measured at T0, after 90 min of surgery (T90), and on postoperative day 10 (D10). In a cecum resection model, 20 rats were randomized into two groups (control and IP parecoxib), and abdominal wound healing and suture leakage were assessed at D10. In both models, PPAs were evaluated quantitatively and qualitatively on D10. Results: Administration of parecoxib significantly decreased the quantity (p < .05) and the severity (p < .01) of PPAs in both models. In addition, parecoxib administration did not cause healing defects or infectious complications in the two models. In the peritoneal burn model, IP or IM parecoxib administration inhibited the increase of postoperative plasma and peritoneum PAI-1 levels, an increase that was observed in the control group (p < .01). No anastomosis leakage could be demonstrated in both groups in the cecum resection model. Conclusion: This study showed that, in these rat models, parecoxib might reduce PPA formation. Confirmation of the safety of parecoxib on intestinal anastomoses is required and should be investigated in further animal models. [less ▲]Detailed reference viewed: 16 (5 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) Pierre Legendres »dogmatische Anthropologie«. Subjektkonstitution im Medium des BlicksHackbarth, Sabine Book published by Turia + Kant (2013)Detailed reference viewed: 18 (2 ULg) Edible insects acceptance by belgian consumers: promising attitude for entomophagy developmentCaparros Megido, Rudy ; Sablon, Ludovic; Geuens, Mélodie et alin Journal of Sensory Studies (2013)Entomophagy is not well accepted in Western European populations but it is common in the world. In the future, populations from developed countries should adapt to other sources of animal proteins because ... [more ▼]Entomophagy is not well accepted in Western European populations but it is common in the world. In the future, populations from developed countries should adapt to other sources of animal proteins because traditional breeding of beef, poultry or pork will become unsustainable. This study was performed to assess the perception of entomophagy in the Belgian population. A slight neophobia was detected but people agreed to evaluate insect preparations. Various insect formulations (mealworms and house crickets) were prepared, and insects associated with known flavors and crispy textures were preferred. After a hedonic test, people seemed to be willing to eat and cook insects in the near future. The opportunity to introduce entomophagy in food habits of Western Euro- pean populations was positively concluded. Integration of edible insects in human food is a potential solution to replace other animal protein sources in a much more sustainable development and will deserve more attention in the future. [less ▲]Detailed reference viewed: 12 (4 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) Local head-loss coefficient at the rectangular transition from a free-surface channel to a conduitVan Nam, Nguyen; Archambeau, Pierre ; Dewals, Benjamin et alin Journal of Hydraulic Engineering (2013), 139(12), 1318-1323Experimental tests have been performed to observe and determine, in stationary flow conditions, the local head loss at the transition from a free surface channel to a conduit. These investigations ... [more ▼]Experimental tests have been performed to observe and determine, in stationary flow conditions, the local head loss at the transition from a free surface channel to a conduit. These investigations considered a wide range of discharge and varied dimensions and positions of a rectangular cross section conduit connected to the downstream extremity of a rectangular free surface channel. From the head loss evaluation results, simple analytical expressions to predict the local head loss coefficient value at the rectangular transition from a channel to a conduit are proposed and validated. [less ▲]Detailed reference viewed: 4 (1 ULg) How could the Io footprint disappear?Hess, Sébastien; Bonfond, Bertrand ; Delamere, Peterin Planetary and Space Science (2013), 89The interaction of Io with the Jovian magnetosphere is the best known – and the most intense – case of satellite-magnetosphere interaction. The interaction involves a power of more than a TeraWatt, a few ... [more ▼]The interaction of Io with the Jovian magnetosphere is the best known – and the most intense – case of satellite-magnetosphere interaction. The interaction involves a power of more than a TeraWatt, a few percent of which are transferred to electrons. These electrons precipitate in the Jovian ionosphere where they light-up bright auroral emissions (several 100's kR to a few 1000's kR). The brightness of the Io-controlled UV auroras is known to vary, due to the Jovian magnetic field tilt, which induces longitudinal variations, and due to the Io torus ever changing parameters (possibly due to Io's volcanic activity), which induce a temporal variation. As Io-controlled UV auroras have been monitored for a long time, the variation of their brightness is well-documented, and the typical amplitude of these variations has been established. However, on June, 7th 2012 an unusual event occurred in the plasma torus surrounding Io, which triggered its own UV emissions on Jupiter in a region mapping to Io's orbit. When Io reached that region, Io's auroral footprint disappeared, its brightness dimming by at least a factor of three to be below the background aurora brightness. Both the auroral event at such a low latitude and the Io footprint disappearance are events that have never been observed before and should be quite rare. However, the question of how the bright Io footprint becomes that weak remains. From a theoretical point-of-view, the Io-Jupiter interaction has been widely studied. In the 80's, it was shown that Alfvén waves are radiated from Io, carrying currents to Jupiter. In the late-2000's, studies showed that dispersive Alfvén waves were likely to cause the acceleration of the electrons powering the auroral emissions, although Io-scale Alfvén waves should be non-dispersive. More recently, a model was built which permits one to compute the ratio between dispersive and non-dispersive waves in the auroral region for satellite-magnetosphere interactions, and thus the brightness of the related aurorae. We use this model to investigate which variation of the interaction parameters could lead to the Io footprint disappearance. [less ▲]Detailed reference viewed: 14 (1 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) Diversité des races de poules locales dans trois régions du monde: Bejaia (Algérie), le Nord du Vietnam et le Bas-Congo (République Démocratique de Congo)Moula, Nassim ; Antoine-Moussiaux, Nicolas ; Philippe, François-Xavier et alConference (2013, November 30)La gestion des ressources génétiques animales est capitale pour le développement de filières de production durables. En production avicole, une érosion graduelle et régulière des ressources génétiques est ... [more ▼]La gestion des ressources génétiques animales est capitale pour le développement de filières de production durables. En production avicole, une érosion graduelle et régulière des ressources génétiques est observée à l'échelle mondiale. Parmi les causes de cette érosion, on retrouve principalement un abandon progressif, volontaire ou contraint, de ces races par les éleveurs. D'autres facteurs aggravant sont les épidémies, les catastrophes naturelles, les conflits et la dégradation de l’habitat de ces animaux. Néanmoins, les races de poules traditionnelles contribuent significativement à la production de viande et d’œufs. Les races indigènes représentent plus de 80 % de la population de volaille mondiale. Cependant, la majorité de ces races n’ont pas été décrites et sont mal connues. La gestion efficace des ressources génétiques animales en général et aviaires en particulier nécessite une identification précise des races concernées, la connaissance des effectifs (taille des populations) et leur distribution géographique, permettant la caractérisation de leur habitat. L’objectif de ce travail est par conséquent de caractériser les races de poules locales dans trois régions du monde : Bejaia (Algérie), le Nord du Vietnam et le Bas-Congo (République Démocratique de Congo) par une description phénotypique, une évaluation des performances zootechniques et une étude des différentes pratiques d’élevage. Une grande diversité phénotypique a été révélée dans chaque région d'étude. Les objectifs d'élevage sont multiples (alimentaire, financier et socioculturel) et variables d’un pays à un autre. Les femmes et les enfants jouent un rôle important dans l'aviculture familiale, quoique variable entre les régions d'étude. Ainsi, les solutions visant à la promotion des races de poules locales doivent être adaptées à la spécificité de chaque contexte. [less ▲]Detailed reference viewed: 13 (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)