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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 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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See detailLes institutions politiques belges
Grandjean, Geoffrey ULg

Learning material (2017)

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See detailLeidenfrost effect at its limits
Maquet, Laurent ULg

Doctoral thesis (2017)

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See detailNO Nightglow studies status
Stiepen, Arnaud ULg; Jain; Deighan et al

Conference (2017, January 16)

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See detailLa théorie du complot : un moyen pour expliquer le monde !
Debras, François ULg

Conference given outside the academic context (2017)

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See detailPrésentation de cas cliniques
WANG, François-Charles ULg

Scientific conference (2017, January 16)

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See detailCryopreservation of chicken primordial germ cells by vitrification and slow-freezing: a comparative study
Tonus, Céline ULg; Connan, Delphine ULg; Waroux, Olivier ULg et al

in Theriogenology (2017), 88

In the present study, we compare a classical slow freezing method and an aseptic vitrification technique to cryopreserve a stable Primordial Gem Cells (PGCs) line issued from the Ardennaise chicken breed ... [more ▼]

In the present study, we compare a classical slow freezing method and an aseptic vitrification technique to cryopreserve a stable Primordial Gem Cells (PGCs) line issued from the Ardennaise chicken breed. Viability immediately after warming was close to 80% and did not differ between the two cryopreservation methods. Proliferation tended to be slower for both cryopreservation methods compared to controls, but the difference was significant only for vitrification. No difference was found between the two methods after flow cytometry analysis of SSEA-1 expression and RT-PCR on several factors related to PGCs phenotype. After one week in culture, all cryopreserved cells reached controls main morphological and expanding (viability/proliferation) features. However, slow freezing generated more unwanted cells clusters than vitrification. After injection of the PGCs into recipient embryos, vitrified PGCs showed a clear, yet not significant, tendency to colonize the gonad at a higher rate than slow frozen PGCs. Slow freezing in cryovials remains simple, inexpensive and less technically demanding than vitrification. Nevertheless, the intrinsic advantages of our aseptic vitrification method and the present study suggest that this should be considered as safer than classical slow freezing for cryopreserving chicken PGCs. [less ▲]

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See detailBreaking Bad News: the TAKE five program
VAN CAUWENBERGE, Isabelle ULg; GILLET, Aline ULg; Bragard, Isabelle ULg et al

Conference (2017, January 14)

Introduction For years, bad news delivery’s impact on patients or their relatives, as well as physicians’ stress has been a major concern. Based on studies claiming the efficacy of training courses to ... [more ▼]

Introduction For years, bad news delivery’s impact on patients or their relatives, as well as physicians’ stress has been a major concern. Based on studies claiming the efficacy of training courses to help physicians delivering such news, many protocols, like SPIKES, BREAKS or SHARE, have emerged worldwide. However, training to such protocol might be time-consuming and not suitable with junior doctors or trainees’ turnover. We hypothesised that a standardized 5-hours training program could improve bad news delivery practice. Participants and methods This preliminary study was conducted in the ED of a tertiary care academic hospital accounting for 90000 ED census per year, 16 attending physicians, 10 junior residents, and 5 trainees per month. Data were collected between November 2015 and April 2016. The study included 3 phases over 4 weeks. Video recorded single role-playing sessions happened the 1st (T1) and the 4th (T3) weeks. A 3-hour theory lesson happened the second week (T2), introducing the basics of therapeutic communication and delivering bad news. Each role-playing session lasted almost 1 hour (10 minutes briefing and medical case reading, 10 minutes role-plays and 40 minutes group debriefing). Bad news delivery performance was evaluated by a 14-points retrospective assessment tool (1). We collected data about the status and impact of a stressful event at 3-days using the French version of the IES-R scale (2). We applied Student t-tests for statistical analysis. Results 14 volunteers (10 trainees and 4 junior emergency physicians) were included in the study. On average, bad-news delivery process took 9’45’’ at T1 and 10’20’’ at T3. From T1 to T3, bad-news delivery performance increased significantly for both junior emergency physicians and trainees (p=0.0003 and p=0.0006, respectively). Further analysis revealed that most relevant increases involved the “situation” (p<0.001), “presentation” (p=0.009), “knowledge” (p=0.037), “emotions” (p=0.01) and “summary” (p=0.001) steps. We also found a significant decrease of the impact of bad-news delivery on trainee physicians’ stress (p=0.006). Discussion and conclusion These preliminary results indicate some potential for this new standardized course of bad news delivery. Apart from allowing physicians increase their communications skills, we believe that this simple 5-hour simulation-training program could alleviate physicians’ stress when they happen to break bad news. References 1. Brunet, A. et al. (2003). Validation of a French version of the Impact of Event Scale-Revised. Can J Psychiatry, 48(1), 56-61. 2. Park, I. et al. (2010). Breaking bad news education for emergency medicine residents: A novel training module using simulation with the SPIKES protocol. J Emerg Trauma Shock, 3(4), 385-388. [less ▲]

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