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See detailTextes sur les signes: les sources latines
Nocchi Macedo, Gabriel ULg

in Nocchi Macedo, Gabriel; Scappaticcio, Maria Chiara (Eds.) Signes dans les textes, textes sur les signes. Actes du colloque international. Liège, 6-7 septembre 2013. (2017)

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See detailUse of complementary biophysical approaches to study the interactions of fatty acid hydroperoxides with biomimetic plant plasma membranes
Deboever, Estelle ULg; Nasir, Mehmet Nail ULg; Deleu, Magali ULg et al

Poster (2017, January 20)

In the actual context, biopesticides have emerged as a main alternative to conventional agriculture1. Hence, elicitors are metabolites naturally produced by microorganisms, pathogenic or not, and plants ... [more ▼]

In the actual context, biopesticides have emerged as a main alternative to conventional agriculture1. Hence, elicitors are metabolites naturally produced by microorganisms, pathogenic or not, and plants which are able to induce the natural resistance of plants. Also, they have proved to be excellent candidates for biological control. In this context, the lipoxygenase pathway leads to the formation of fatty acid degradation products, called oxylipins, which appear to be crucial agents in plant defence mechanisms2,3. Moreover, with their broad spectrum of action and their possible inducibility, oxylipins appear to be promising candidates for their use as elicitors4. This work focuses on two hydroperoxy-derived oxylipins, the 13(S)-hydroperoxy-octadecadienoic acid (13-HPOD) and the 13(S)-hydroperoxy-octadecatrienoic acid (13-HPOT). The study of the interaction of such compounds with representative plant plasma membrane lipids is essential to understand plant resistance mechanisms. Several in silico and experimental techniques of biophysics showed that acyl-hydroperoxides have significant adsorption capacity and a strong affinity for model membranes. They may also penetrate biological membrane but no permeabilisation effect was observed in this work. Slight conformational differences seem to have a significant impact on their ability to interact with plant plasma membranes. Based on these results, further investigation of the interactions of fatty acids hydroperoxides, even more on the 9-forms, with plant plasma membranes and eventually in the presence of phytopathogenic species, would allow a better understanding of the innate immunity and, on the longer term, could lead to the development of new elicitors with biological mechanisms potentially independent of membrane protein receptors. [less ▲]

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See detailÉtude du cytosquelette de microtubules et implication de la vimentine dans le développement postnatal de la cochlée chez les rongeurs
Renauld, Justine ULg

Doctoral thesis (2017)

According to the World Health Organization, nearly 5% of the population suffers from hearing impairments. These can lead to social isolation, depression, or a reduction in professional abilities. There ... [more ▼]

According to the World Health Organization, nearly 5% of the population suffers from hearing impairments. These can lead to social isolation, depression, or a reduction in professional abilities. There are two types of hearing impairments : conductive hearing impairment and sensorineural hearing impairment. The first results from a defect in sound conduction at the level of the outer or middle ear, the latter results from defects in the cochlea or auditory nerve. In recent years, most studies on the organ of hearing have focused on sensory cells, which are actual receptors of auditory information, whereas supporting cells have been little explored. However, the latter, surrounding the sensory cells, contain a highly developed cytoskeleton, essential to the architecture of the mature organ of Corti. During this thesis work, we first observed the setting up of microtubules within the supporting cells of the organ of Corti. Our morphological data revealed important changes in microtubular cytoskeleton of these cells during the first week of life. We identified an arrangement of microtubules into two distinct bundles. We then demonstrated a modification in the morphology of these microtubules, revealing an increase in the diameter and the number of protofilaments of these cells. We finally demonstrated that tubulin βV has a more specific spatiotemporal distribution than the other tubulins. This characteristic suggests that tubulin βV plays an important role in the maturation of the Corti organ. In the second part of this thesis, we analyzed the involvement of vimentin in cochlear development, and more particularly in the opening of the intercellular spaces and in the myelination of the spiral ganglion, which is the first relay of the auditory pathway. In order to study the role of vimentin in the development of the inner ear, we examined the cochlear morphology and auditory capacities of vimentin deficient mice. Our results indicated that the absence of vimentin does not seem to affect the architecture of the organ of Corti. We then showed a slight morphological difference in the nerve fibers between wildtype and vimentin-knockout mice. We finally checked the hearing physiology of these mice and concluded that vimentin does not play a major role in hearing. [less ▲]

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See detailUber-like Models for the Electrical Industry
Ernst, Damien ULg

Speech/Talk (2017)

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See detailLes codices miniatures grecs et latin d'Égypte : contenu, forme et fonction
Carlig, Nathan ULg

Scientific conference (2017, January 19)

Étude globale des codices miniatures grecs et latin provenant d’Égypte. L’examen de leur contenu, de leur forme et de leur mise en page, ainsi que de leur provenance, lorsqu’elle est connue, permettront ... [more ▼]

Étude globale des codices miniatures grecs et latin provenant d’Égypte. L’examen de leur contenu, de leur forme et de leur mise en page, ainsi que de leur provenance, lorsqu’elle est connue, permettront d’identifier des contextes de production et d’utilisation de ces livres de petit format. [less ▲]

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See detailGlobal Simulation of UV atmospheric Emissions
Gonzalez-Galindo; Lopez-Valverde; Forget et al

Poster (2017, January 19)

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See detailAvantages/inconvénients liés au maintien à domicile ou au placement en institution de la personne âgée
Adam, Stéphane ULg

Conference given outside the academic context (2017)

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See detailVers une société post-croissance : intégrer les défis écologiques, économiques et sociaux
Cassiers, Isabelle; Maréchal, Kevin ULg; Méda, Dominique

Book published by Editions de l'Aube (2017)

Le terme post-croissance désigne l’entrée dans une ère que nous ne parvenons pas encore à nommer, si ce n’est par référence à celle que nous quittons. Les symptômes qui signent la fin d’une époque sont ... [more ▼]

Le terme post-croissance désigne l’entrée dans une ère que nous ne parvenons pas encore à nommer, si ce n’est par référence à celle que nous quittons. Les symptômes qui signent la fin d’une époque sont clairs et sans appel : la poursuite de la croissance économique ne constitue plus un projet de société crédible. Toutefois, y renoncer pose aux économistes (théoriciens et praticiens) des défis majeurs qui exigent de reprendre à leur racine, sous un éclairage transdisciplinaire, les questions dont ils traitent couramment. Ensemble, les neuf chercheurs réunis dans cet ouvrage s’interrogent : quels sont les problèmes majeurs qui surgissent à l’esprit dès lors que l’on abandonne un objectif de croissance continue ? Par où passe la transition vers un autre horizon ? Quels sont les courants de pensée et les modes de gouvernance susceptibles d’articuler un projet cohérent ? Chacun des auteurs apporte un regard spécifique, une pièce au puzzle qu’il s’agirait à l'avenir d’assembler. [less ▲]

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See detailSous-arbres induits pleinement feuillus
Vandomme, Elise ULg

Scientific conference (2017, January 19)

In the last 60 years, polyominoes have been the object of many investigations. A central problem, that is still open, is to determine the number of polyominoes with n square cells. An approach to solve ... [more ▼]

In the last 60 years, polyominoes have been the object of many investigations. A central problem, that is still open, is to determine the number of polyominoes with n square cells. An approach to solve the problem is to use a combinatorial description of polyominoes and to try to describe particular families of polyominoes. Behind each polyomino there is a graph whose vertices are the cells, such that two vertices are adjacent if their cells share a common edge. In this framework, one can study the polyominoes with an acyclic graph, called tree-like polyominoes. In 2016, Blondin-Massé et al. determined the maximal number that can have a tree-like polyomino with n cells. In this talk, we generalize this problem to graphs in general and we show this problem is NP-complete. However, the problem becomes polynomial when we restrict ourselves to trees or to graphs with a constant tree-width. [less ▲]

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See detailGenetics of Pituitary Tumor Syndromes
Daly, Adrian ULg; BECKERS, Albert ULg

in Melmed, Shlomo (Ed.) The Pituitary (2017)

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See detailMoresnet-Neutre (1816-1919): Histoire et mémoire d'une curiosité géopolitique
Brüll, Christoph ULg

Conference given outside the academic context (2017)

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See detailIntegrated approach for ethics in research for young researchers at the University of Liege
Halleux, Isabelle ULg

E-print/Working paper (2017)

For ensuring good practices in research from the beginning and developing a culture of ethics, ULg developed an integrated approach focusing on young researchers. The objective is to instill, as soon as ... [more ▼]

For ensuring good practices in research from the beginning and developing a culture of ethics, ULg developed an integrated approach focusing on young researchers. The objective is to instill, as soon as possible, a good perception of what is quality in research, considering methodology, project management and ethics as norms and moral positioning for solving dilemma. Actions, coordinated by the Council for Ethics and Scientific Integrity (CEIS), are developed simultaneously through 5 axes. Young researchers are involved at all levels of the process, directly or as representative of the PhD Association. 1. Training: Sensitization and education to ethics; development of professional capacities, incl. data analysis & open data; seminaries with supervisors and PhDs ("duos") 2. Forum: ethics on the public space – Seminaries, conference, round tables, intervision, discussion and exchange on questions, dilemma, case-studies, with the help of external experts 3. Research appraisal: requirement for an ethics appraisal of each research project, with a special focus on human and social sciences, with the help of disciplinary ethics committees 4. Ethics analysis: Analysis of special questions, complains, problems, and decision making in case of violation of integrity 5. Regulation: Writing of procedures, dissemination of documents, recommendations and case-studies, link to the HR Strategy for researchers and the Charter and Code. In 2016, successful activities took place : - about 500 PhDs (25%) participated directly in the "Go2thesis training" (incl. 1 day on project management and ethics), dedicated trainings (introduction, special questions) and forum-debates - all the research projects, incl. PhD grants, supported by ULg were requested to provide an ethical issue check list, based on the H2020 standards. The R&D Office helped to explain about the issues and resources, and to orient the applicant to the ad hoc ethics committee - special requests were analyzed by the CEIS for several PhD's sensitive projects - Information was provided to PhDs regarding authorship, crowdfunding, privacy, open data and security while travelling New projects will be developed for (1) strengthening the relation between CEIS-ethics committee-doctoral school-supervisor-PhD (2) involving all the new PhDs in the training and forum, and (3) ensure the ethics appraisal during the whole duration of the PhD thesis (i.e. special chapter in the annual report). This presentation aims to exchange about what was done, the actual and expected impact of actions, what is going right and wrong, and how ULg is managing this dynamics as part of the HR Strategy for researchers project. A discussion with participants is expected on results and new projects. [less ▲]

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See detailA persistent meteoric layer in Mars' atmosphere
Crismani; Schneider; Plane et al

Poster (2017, January 18)

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See detailPresent-day central African forest is a legacy of the 19th century human history
Morin, Julie ULg; Fayolle, Adeline ULg; Favier, Charly et al

in eLife (2017)

The populations of light-demanding trees that dominate the canopy of central African forests are now aging. Here, we show that the lack of regeneration of these populations began ca. 165 ya (around 1850 ... [more ▼]

The populations of light-demanding trees that dominate the canopy of central African forests are now aging. Here, we show that the lack of regeneration of these populations began ca. 165 ya (around 1850) after major anthropogenic disturbances ceased. Since 1885, less itinerancy and disturbance in the forest has occurred because the colonial administrations concentrated people and villages along the primary communication axes. Local populations formerly gardened the forest by creating scattered openings, which were sufficiently large for the establishment of light-demanding trees. Currently, common logging operations do not create suitable openings for the regeneration of these species, whereas deforestation degrades landscapes. Using an interdisciplinary approach, which included paleoecological, archaeological, historical, and dendrological data, we highlight the long-term history of human activities across central African forests and assess the contribution of these activities to present-day forest structure and composition. The conclusions of this sobering analysis present challenges to current silvicultural practices and to those of the future. [less ▲]

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See detailFlexible Bayesian Models for Interval-Censored Survival Data
Cetinyürek, Aysun ULg

Doctoral thesis (2017)

Interval-censored time-to-event data arise frequently in clinical trials and longitudinal studies, where the event of interest is only known to have occurred between the two consecutive visits. Interval ... [more ▼]

Interval-censored time-to-event data arise frequently in clinical trials and longitudinal studies, where the event of interest is only known to have occurred between the two consecutive visits. Interval-censoring is a natural generalization of right censored time-to-event data. For right-censored data, extensive number of statistical techniques are available to tackle most research questions under a variety of assumptions. However, for interval-censored data, less well developed procedures are available. A sparse offer in statistical softwares to handle this type of censoring has driven many researchers to use imputation techniques, especially right-point or mid-point imputation. However such imputation strategies can lead to misleading inferences. Our thesis proposes and studies the properties of innovative methods to analyze such data. In the first part of the text, we have extended a Bayesian density estimation procedure for grouped data to estimate hazard ratios and survival functions from interval-censored data. If one further assumes proportionality of the hazards, the proposed strategy also provides estimates of global covariate effects. Clearly, the proposed method provides very good estimates for the regression coefficients and successfully approximates the baseline survival function when the mean interval width is smaller than some threshold defined from the data standard deviation. In a Cox proportional hazards model, the observations are assumed to be independent. However, this may not be true in certain situations where the observed units are clustered or subject to multiple measurements. A number of approaches generalizing Cox's PH model to handle correlated interval-censored data have been proposed in the literature. The shared frailty model is a popular tool to analyze correlated right-censored time-to-event data. Frailty models have also been adapted to handle interval-censored data. In the case of interval-censored time-to-event data, the inclusion of frailties results in complicated intractable likelihoods. In the second part of this thesis, we propose flexible frailty models for analyzing such data by assuming a smooth flexible form for the conditional time-to-event distribution and a parametric or a flexible form for the frailty distribution. It has been indicated in the literature in different contexts that the misspecification of the random effect distribution can influence the estimation of quantities of primary interest, like the fixed effects. To circumvent such misspecification, we have suggested modeling the distribution of the frailty in a flexible way using P-splines or a gamma shape mixture (GSM) distribution. The biggest advantage of using a flexible specification for the density of frailty arises when its shape is of specific interest. If it is considered as a nuisance, assuming a simpler lognormal or gamma frailty would be an adequate solution to draw conclusions related to other model parameters, such as regression coefficients and variance of frailties. Indeed, it was shown in the simulation study that the regression parameter estimates in a shared frailty PH model are robust to the misspecification of the frailty density. Moreover the use of a flexible form for the frailty does not cause any loss of precision in the estimation of regression parameters when compared to the simpler parametric frailty model. Both models provide the possibility to visualize the baseline density and survival functions. Given sufficiently large sample sizes, the flexible approach produces smooth and accurate posterior estimates for the baseline survival function and for the frailty density, and can correctly detect and identify unusual frailty density forms. [less ▲]

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See detailGlobal UV Imaging by MAVEN/IUVS: Diurnal Cloud Formation, Dust Storms and Atmospheric Scattering.
Schneider; Deighan; Jain et al

Conference (2017, January 17)

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See detailThree Types of Aurora observed by MAVEN/IUVS: Implications for Mars’ upper Atmosphere Energy Budget
Connour; Schneider; Jain et al

Poster (2017, January 17)

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See detailIs Büchi's theorem useful for you? (for an audience of logicians)
Rigo, Michel ULg

Conference (2017, January 17)

Almost a century ago, Presburger showed that the first order theory of the natural numbers with addition is decidable. Following the work of B\"uchi in 1960, this result still holds when adding a function ... [more ▼]

Almost a century ago, Presburger showed that the first order theory of the natural numbers with addition is decidable. Following the work of B\"uchi in 1960, this result still holds when adding a function $V_k$ to the structure, where $V_k(n)$ is the largest power of $k\ge 2$ diving $n$. In particular, this leads to a logical characterization of the $k$-automatic sequences. During the last few years, many applications of this result have been considered in combinatorics on words, mostly by J. Shallit and his coauthors. In this talk, we will present this theorem of B\"uchi where decidability relies on finite automata. Then we will review some results about automatic sequences or morphic words that can be proved automatically (i.e., the proof is carried on by an algorithm). Finally, we will sketch the limitation of this technique. With a single line formula, one can prove automatically that the Thue-Morse word has no overlap but, hopefully, not all the combinatorial properties of morphic words can be derived in this way. We will not assume any background in combinatorics on words from the audience. [less ▲]

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