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See detailRecent Northern Hemisphere stratospheric HCl increase due to atmospheric circulation changes
Mahieu, Emmanuel ULg; Chipperfield, M. P.; Notholt, J. et al

in Nature (2014), 515(7525), 104--107

The abundance of chlorine in the Earth’s atmosphere increased considerably during the 1970s to 1990s, following large emissions of anthropogenic long-lived chlorine-containing source gases, notably the ... [more ▼]

The abundance of chlorine in the Earth’s atmosphere increased considerably during the 1970s to 1990s, following large emissions of anthropogenic long-lived chlorine-containing source gases, notably the chlorofluorocarbons. The chemical inertness of chlorofluorocarbons allows their transport and mixing throughout the troposphere on a global scale[1], before they reach the stratosphere where they release chlorine atoms that cause ozone depletion[2]. The large ozone loss over Antarctica[3] was the key observation that stimulated the definition and signing in 1987 of the Montreal Protocol, an international treaty establishing a schedule to reduce the production of the major chlorine- and bromine-containing halocarbons. Owing to its implementation, the near-surface total chlorine concentration showed a maximum in 1993, followed by a decrease of half a per cent to one per cent per year[4], in line with expectations. Remote-sensing data have revealed a peak in stratospheric chlorine after 1996[5], then a decrease of close to one per cent per year[6,7], in agreement with the surface observations of the chlorine source gases and model calculations[7]. Here we present ground-based and satellite data that show a recent and significant increase, at the 2σ level, in hydrogen chloride (HCl), the main stratospheric chlorine reservoir, starting around 2007 in the lower stratosphere of the Northern Hemisphere, in contrast with the ongoing monotonic decrease of near-surface source gases. Using model simulations, we attribute this trend anomaly to a slowdown in the Northern Hemisphere atmospheric circulation, occurring over several consecutive years, transporting more aged air to the lower stratosphere, and characterized by a larger relative conversion of source gases to HCl. This short-term dynamical variability will also affect other stratospheric tracers and needs to be accounted for when studying the evolution of the stratospheric ozone layer. [less ▲]

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See detailThe Robust Economic Statistical Design of the Hotelling’s T^2 Chart
Faraz, Alireza ULg; Chalaki, Kamyar; Saniga, Erwin et al

in Communications in Statistics : Theory & Methods (2014)

Economic statistical designs aim at minimizing the cost of process monitoring when a specific scenario or a set of estimated process and cost parameters is given. However, in practical situations the ... [more ▼]

Economic statistical designs aim at minimizing the cost of process monitoring when a specific scenario or a set of estimated process and cost parameters is given. However, in practical situations the process may be affected by more than one scenario which may lead to severe cost penalties for upsetting the true scenario. This paper presents the robust economic statistical design (RESD) of the T^2 chart to reduce the monetary losses when there are multiple distinct scenarios. The genetic algorithm optimization method is employed here to minimize the total expected monitoring cost across all distinct scenarios. Through two numerical examples the proposed method is illustrated. Simulation studies indicate that the robust economic statistical designs should be encouraged in practice. [less ▲]

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See detailForest inventory with Terrestrial LiDAR: what about Hand-Held Mobile LiDAR?
Bauwens, Sébastien ULg; Bartholomeus, Harm; Piboule, Alexandre et al

Conference (2014, November 05)

For a decade, studies of the application of static Terrestrial Laser Scanner (TLS) in plotwise forest inventories are giving more and more effective results. In spite of the improvements occurring in ... [more ▼]

For a decade, studies of the application of static Terrestrial Laser Scanner (TLS) in plotwise forest inventories are giving more and more effective results. In spite of the improvements occurring in processing scan data to extract forest attributes, the occlusion effect is still limiting the processing efficiency. A multi-scan approach is recommended to reduce this effect. However, such approach needs pre-scan preparations (setting up the plot, targets positioning), it requires data registration and it comes at a higher data collection cost. In this study we explore the potential of a Hand-held mobile LiDAR System (HMLS) as new LiDAR tool to scan forest plots. HMLS data are compared to static TLS data (single and multi-scan) in terms of data acquisition, registration time and quality of automatic DBH extraction. The low weight, small size of the instrument and no targets requirements reduce the time of pre-scan preparations to the time needed for single scan which is 6 times less than scanning a plot with 5 scans. The registration time depends of the time spent to scan the plot and it is of the same magnitude than single scan. The resulting point cloud of the HMLS is noisier than TLS point clouds. Nevertheless, error on DBH estimations is similar to scanning a plot with a TLS positioned at 5 locations. RMSE is higher than multi-scan and close to single scan for trees detected by the both LiDAR technologies. This first study exhibits the high potential of HMLS by its simple use, which needs only one operator while presenting similar results in automatic DBH extraction than static TLS. Technology and registering method improvements of this type of mobile LiDAR will reduce the noise of the point cloud, which might reduce the DBH RMSE. [less ▲]

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See detailCarbon capture and storage at the University of Liège
Léonard, Grégoire ULg

Scientific conference (2014, November 05)

The objective of this presentation was to discuss the main technologies of CO2 capture, re-use and storage, with their respective characteristics (costs, challenges...), advantages and drawbacks. Then ... [more ▼]

The objective of this presentation was to discuss the main technologies of CO2 capture, re-use and storage, with their respective characteristics (costs, challenges...), advantages and drawbacks. Then, the second part of the presnetation highlights the main research results that have been achieved at the University of Liège in this field. [less ▲]

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See detailLa dépression chez l'adolescent: Mieux comprendre pour mieux agir
Boulard, Aurore ULg

Conference given outside the academic context (2014)

La dépression à l’adolescence fait depuis quelques années l’objet d’études épidémiologiques. Chez les adolescents, les taux de prévalence varient de 5 à 7% pour l’épisode dépressif majeur (EDM) et touche ... [more ▼]

La dépression à l’adolescence fait depuis quelques années l’objet d’études épidémiologiques. Chez les adolescents, les taux de prévalence varient de 5 à 7% pour l’épisode dépressif majeur (EDM) et touche deux fois plus de filles que de garçons. Selon une estimation, deux tiers d’entre eux ne seraient pas médicalement et/ou psychologiquement soignés. Pourtant les conséquences de ces épisodes dépressifs sont nombreuses et graves: troubles du caractère, échecs scolaires, conduites suicidaires. Un rapport récent de l’OMS montre qu’à l’heure actuelle, la dépression chez les adolescents âgés de 12 à 19 ans est la première cause de maladie et de handicap. Face à ce constat, il est de la plus haute importance de mieux comprendre cette maladie qui ne s’exprime pas de la même manière qu’à l’âge adulte et se confond régulièrement avec la « crise d’adolescence » afin de pouvoir prendre en charge ces adolescents et les aider. [less ▲]

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See detailPollution and Siltation of Rivers in the Western Highlands of Cameroon: a Consequence of Farmland Erosion by Runoff
Djoukeng, Henri Grisseur ULg; Tankou, Christopher Mubeteneh; Degré, Aurore ULg

Conference (2014, November 05)

In the western highlands agro-ecological zone of Cameroon, rivers are constantly silted and polluted with waste from cultivated plots. This study investigated on the characterization and quantification of ... [more ▼]

In the western highlands agro-ecological zone of Cameroon, rivers are constantly silted and polluted with waste from cultivated plots. This study investigated on the characterization and quantification of sediment from plots cultivated in the watershed Méloh; among these sediment we highlighted soil, plant residues, chemical packages and plastic casing used for irrigation. In a natural rocky bottom wells, we performed for a period of three years the collection, differentiation and measurement of trapped sediment in the cultivated part of river that runs through the watershed. The total cultivated area is about 7.5 ha; slopes are operated between 14% and 17%. During the years 2012 and 2013 where farmers practiced both flatbed and ridging along the steepest slope, two methods of land preparation that do not contribute positively to water conservation, we collected an average of 10.429 t.ha-1. During the 2013 crop year, with the participation of curious farmers we experimented tied ridging in a potato; this technique was adopted on 75% of plots in 2014 and we collected 3.586 t.ha-1, a decrease of 65.61% compared to the average of previous years. This study showed that traditional agricultural practices are a cause of siltation and pollution of the Méloh river, thus almost all rivers in the study area by what the topography is similar and agriculture the main activity. Tied ridging significantly reduced siltation of rivers; it is thus an effective technique to fight against water pollution in mountain agriculture. [less ▲]

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See detailBlackouts: des vérités qui dérangent
Ernst, Damien ULg

Speech (2014)

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See detailIncorporate agroecology within research : The on-going story of four young researchers
Hatt, Séverin ULg; Artru, Sidonie ULg; Boeraeve, Fanny ULg et al

in Broadening Scopes on Food, Squeezing Urban Hinterlands (2014, November 04)

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See detailÉmissions gazeuses en production porcine
Philippe, François-Xavier ULg

Conference (2014, November 04)

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See detailSouthern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection
Sana, H.; Le Bouquin, J.-B.; Lacour, S. et al

in Astrophysical Journal Supplement Series (2014), 215

Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at ... [more ▼]

Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at separations between 1 and 100 milliarcsec (mas) remain mostly unknown due to intrinsic observational limitations. At a typical distance of 2 kpc, this corresponds to projected ph [less ▲]

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See detailLa voix transgenre
Morsomme, Dominique ULg; Remacle, Angélique ULg

Scientific conference (2014, November 04)

Notre société admet deux sexes : féminin et masculin. Cependant, certaines personnes ne s’identifient pas au sexe et au genre qui leur ont été attribués à la naissance. La personne transsexuelle éprouve ... [more ▼]

Notre société admet deux sexes : féminin et masculin. Cependant, certaines personnes ne s’identifient pas au sexe et au genre qui leur ont été attribués à la naissance. La personne transsexuelle éprouve un désir profond de vivre comme une personne du sexe opposé à son sexe biologique. Lors du processus de transition où ont lieu les transformations nécessaires au changement de genre, la logopédie a pour but d’améliorer la cohérence entre l’apparence de la personne et sa voix. Dans cette conférence, nous présenterons des outils pour l’évaluation et la prise en charge permettant la féminisation vocale en cas de transsexualité homme vers femme. Une revue de la littérature scientifique récente nous amènera à discuter de l’efficacité des méthodes de féminisation vocale existantes. Ces techniques seront décrites et illustrées par des cas cliniques. [less ▲]

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See detailSupercritical Carbon Dioxide Assisted Impregnation to Prepare Drug-eluting Polymer Implants
Champeau, Mathilde ULg

Doctoral thesis (2014)

The scCO2 impregnation process is a promising alternative to other manufacturing process to prepare drug-eluting polymer implants. This work enabled to rationalize the influence of the key parameters ... [more ▼]

The scCO2 impregnation process is a promising alternative to other manufacturing process to prepare drug-eluting polymer implants. This work enabled to rationalize the influence of the key parameters governing this process and to determine in which extent this process can be used to prepare drug-eluting implants. We have combined the information obtained with traditional polymer characterization techniques and a newly characterization set-up we have developed that is based on in situ FTIR micro-spectroscopy. We have worked on the impregnation of sutures made of PLLA, PP and PET with two anti-inflammatory drugs namely ketoprofen and aspirin. Firstly, the thermodynamic behaviors of the systems drug/CO2 (solubility and speciation of the drug) and polymer/CO2 (CO2 sorption, polymer swelling, evolution of the polymer microstructure and of the tensile properties) were studied as a function of pressure and temperature. Then, the scCO2 impregnation process was investigated. The impact of the operational conditions on the drug loading (contact time, pressure, temperature and depressurization conditions) was explored and accounted regarding to the CO2 sorption, the swelling, the drug solubility as well as the changes in the polymer microstructure with the experimental conditions and the presence of the drug. The drug/polymer affinity was also explored. The tensile properties of the impregnated fibers were also evaluated. PLLA was more impregnated (up to 32%) than PP and PET (up to 5%) in the investigated conditions. Finally, we have shown that the drug release can be tuned from 3 days to 3 months by varying the impregnation and depressurization conditions on the system PLLA/Ketoprofen. [less ▲]

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See detailOrigin and immunoescape of uterine cervical cancer
Van hede, Dorien ULg; Langers, Inge ULg; DELVENNE, Philippe ULg et al

in Presse Médicale (2014)

Human papillomavirus associated uterine cervical cancer is an important public health problem since it is classified as the fourth most common cancer in women worldwide with more than 500 000 recorded ... [more ▼]

Human papillomavirus associated uterine cervical cancer is an important public health problem since it is classified as the fourth most common cancer in women worldwide with more than 500 000 recorded cases. This review is focused on where and why HPV infection induces cervical cancers and how this virus avoids the host immune response. Immunological therapeutic approaches are also addressed. [less ▲]

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See detailLe nouveau cadre d’action en matière de climat et d’énergie à l’horizon 2030
Habran, Maxime ULg

E-print/Working paper (2014)

Cette note a pour but de fournir un éclairage sur le nouveau cadre d'action européen en matière de climat et d'énergie

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See detailLes formations cambro-ordoviciennes du Massif de Stavelot et le conglomérat permien (Poudingue de Malmedy), sur les cartes Harzé- La Gleize et Stavelot - Malmedy.
Lamberty, Pauline ULg; Marion, Jean-Marc ULg

Diverse speeche and writing (2014)

Livret-guide de l'excursion réalisée dans le cadre du Programme* de Révision de la carte géologique de la Wallonie (*commandé par le SPW). La journée est dédiée aux formations cambriennes (Wanne, La Venne ... [more ▼]

Livret-guide de l'excursion réalisée dans le cadre du Programme* de Révision de la carte géologique de la Wallonie (*commandé par le SPW). La journée est dédiée aux formations cambriennes (Wanne, La Venne et La Gleize), ordoviciennes (Jalhay et Ottré), ainsi qu'aux dépôts conglomératiques permiens, connus sous le nom de "Poudingue de Malmedy" qui affleurent dans le Massif de Stavelot (localités de Trois-Ponts, Stavelot, Basse-Bodeux, Stoumont, ainsi que la vallée de la Lienne). [less ▲]

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See detailOccurence of Satellite RNAs associated with Cucumber mosaic virus isolated from banana (Musa sp.) in Ivory Coast
Kouadio, Kouakou Théodore; De Clerck, Caroline ULg; Agneroh, TA et al

in British Society for Plant Pathology - New Disease Reports (2014), 30

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See detailA Phylogenomic analysis of the origin of plastids
Cornet, Luc ULg; Javaux, Emmanuelle ULg; Wilmotte, Annick ULg et al

Conference (2014, November 03)

Cyanobacteria are a morphologically diverse phylum, with their first occurrence dating from the Precambrian. Oxygenic photosynthesis appeared in this group during the same geological period. Several ... [more ▼]

Cyanobacteria are a morphologically diverse phylum, with their first occurrence dating from the Precambrian. Oxygenic photosynthesis appeared in this group during the same geological period. Several publications have established, without any doubt, that plastids (both primary and complex) form a monophyletic ensemble emerging from Cyanobacteria. However, the exact position of plastids within Cyanobacteria is still uncertain, with several recent papers leading to very different hypotheses. Here we present a phylogenomic analysis of the origin of plastids. Our study takes advantage of all the available genomes and thus represents the best taxonomic sampling seen so far: 140 genomes of Cyanobacteria, 101 genomes of plastids and 27 outgroups taken in Melainabacteria and Chloroflexi. It esults in an analysis using state-of- the-art methods (e.g., orthology assessment using USEARCH and rthoMCL, phylogenetic inference using CAT and CAT-GTR models) based on more than 160 protein alignments totalizing over 20,000 unambiguously aligned amino acids. To confirm our results, we performed gene jackknife inferences and gene reconciliation analyses on the same dataset. We expect that out approach accounts for potential phylogenetic artefacts due to changes in the evolutionary process having occurred when the guest cyanobacterium became an endosymbiont and eventually a plastid. Meanwhile, we improve the phylogeny of Cyanobacteria per se, notably because of the presence of Melainabacteria in our dataset. [less ▲]

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See detailSearching for faint companions with VLTI/PIONIER. II. 92 main sequence stars from the Exozodi survey
Marion, Lindsay ULg; Absil, Olivier ULg; Ertel, S. et al

in Astronomy and Astrophysics (2014), 570

Context. The Exozodi survey aims to determine the occurrence rate of bright exozodiacal discs around nearby main sequence stars using infrared interferometry. Although the Exozodi survey targets have been ... [more ▼]

Context. The Exozodi survey aims to determine the occurrence rate of bright exozodiacal discs around nearby main sequence stars using infrared interferometry. Although the Exozodi survey targets have been carefully selected to avoid the presence of binary stars, the results of this survey can still be biased by the presence of unidentified stellar companions. <BR /> Aims: Using the PIONIER data set collected within the Exozodi survey in 2012, we aim to search for the signature of point-like companions around the Exozodi target stars. <BR /> Methods: We make use of both the closure phases and squared visibilities collected by PIONIER to search for companions within the ~100 mas interferometric field of view. The presence of a companion is assessed by computing the goodness of fit to the data for a series of binary models with various separations and contrasts. <BR /> Results: Five stellar companions are resolved for the first time around five A-type stars: HD 4150, HD 16555, HD 29388, HD 202730, and HD 224392 (although the companion to HD 16555 was independently resolved by speckle interferometry while we were carrying out the survey). In the most likely case of main sequence companions, their spectral types range from A5V to K4V. Three of these stars were already suspected to be binaries from Hipparcos astrometric measurements, although no information was available on the companions themselves so far. In addition to debiasing the statistics of the Exozodi survey, these results can also be used to revise the fraction of visual binaries among A-type stars, suggesting that an extra ~13% A-type stars are visual binaries in addition to the ones detected in previous direct imaging surveys. <BR /> Conclusions: We estimate that about half the population of nearby A-type stars could be resolved as visual binaries using a combination of state-of-the-art interferometry and single-aperture imaging, and we suggest that a significant fraction of these binaries remains undetected to date. [less ▲]

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See detailA near-infrared interferometric survey of debris-disk stars. IV. An unbiased sample of 92 southern stars observed in H band with VLTI/PIONIER
Ertel, S.; Absil, Olivier ULg; Defrere, D. et al

in Astronomy and Astrophysics (2014), 570

Context. Detecting and characterizing circumstellar dust is a way to study the architecture and evolution of planetary systems. Cold dust in debris disks only traces the outer regions. Warm and hot ... [more ▼]

Context. Detecting and characterizing circumstellar dust is a way to study the architecture and evolution of planetary systems. Cold dust in debris disks only traces the outer regions. Warm and hot exozodiacal dust needs to be studied in order to trace regions close to the habitable zone. <BR /> Aims: We aim to determine the prevalence and to constrain the properties of hot exozodiacal dust around nearby main-sequence stars. <BR /> Methods: We searched a magnitude-limited (H <= 5) sample of 92 stars for bright exozodiacal dust using our VLTI visitor instrument PIONIER in the H band. We derived statistics of the detection rate with respect to parameters, such as the stellar spectral type and age or the presence of a debris disk in the outer regions of the systems. We derived more robust statistics by combining our sample with the results from our CHARA/FLUOR survey in the K band. In addition, our spectrally dispersed data allowed us to put constraints on the emission mechanism and the dust properties in the detected systems. <BR /> Results: We find an overall detection rate of bright exozodiacal dust in the H band of 11% (9 out of 85 targets) and three tentative detections. The detection rate decreases from early type to late type stars and increases with the age of the host star. We do not confirm the tentative correlation between the presence of cold and hot dust found in our earlier analysis of the FLUOR sample alone. Our spectrally dispersed data suggest that either the dust is extremely hot or the emission is dominated by the scattered light in most cases. The implications of our results for the target selection of future terrestrial planet-finding missions using direct imaging are discussed. [less ▲]

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