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See detailUncertainty quantification of Antarctic contribution to sea-level rise using the fast Elementary Thermomechanical Ice Sheet (f.ETISh) model
Bulthuis, Kevin ULg; Arnst, Maarten ULg; Pattyn, Frank et al

Conference (2017, April)

Uncertainties in sea-level rise projections are mostly due to uncertainties in Antarctic ice-sheet predictions (IPCC AR5 report, 2013), because key parameters related to the current state of the Antarctic ... [more ▼]

Uncertainties in sea-level rise projections are mostly due to uncertainties in Antarctic ice-sheet predictions (IPCC AR5 report, 2013), because key parameters related to the current state of the Antarctic ice sheet (e.g. sub-ice- shelf melting) and future climate forcing are poorly constrained. Here, we propose to improve the predictions of Antarctic ice-sheet behaviour using new uncertainty quantification methods. As opposed to ensemble modelling (Bindschadler et al., 2013) which provides a rather limited view on input and output dispersion, new stochastic methods (Le Maître and Knio, 2010) can provide deeper insight into the impact of uncertainties on complex system behaviour. Such stochastic methods usually begin with deducing a probabilistic description of input parameter uncertainties from the available data. Then, the impact of these input parameter uncertainties on output quantities is assessed by estimating the probability distribution of the outputs by means of uncertainty propagation methods such as Monte Carlo methods or stochastic expansion methods. The use of such uncertainty propagation methods in glaciology may be computationally costly because of the high computational complexity of ice-sheet models. This challenge emphasises the importance of developing reliable and computationally efficient ice-sheet models such as the f.ETISh ice-sheet model (Pattyn, 2015), a new fast thermomechanical coupled ice sheet/ice shelf model capable of handling complex and critical processes such as the marine ice-sheet instability mechanism. Here, we apply these methods to investigate the role of uncertainties in sub-ice-shelf melting, calving rates and climate projections in assessing Antarctic contribution to sea-level rise for the next centuries using the f.ETISh model. We detail the methods and show results that provide nominal values and uncertainty bounds for future sea- level rise as a reflection of the impact of the input parameter uncertainties under consideration, as well as a ranking of the input parameter uncertainties in the order of the significance of their contribution to uncertainty in future sea-level rise. In addition, we discuss how limitations posed by the available information (poorly constrained data) pose challenges that motivate our current research. [less ▲]

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See detailBien raisonner en TSUM (Transition Secondaire-Université en Mathématiques)
Bair, Jacques ULg

E-print/Working paper (2017)

Bien raisonner est assurément une des compétences clés que doivent acquérir et développer les étudiants entrant à l’Université. Nous y consacrons entièrement ce travail illustré par de nombreux exemples ... [more ▼]

Bien raisonner est assurément une des compétences clés que doivent acquérir et développer les étudiants entrant à l’Université. Nous y consacrons entièrement ce travail illustré par de nombreux exemples construits à partir de notre expérience professionnelle. En premier lieu, nous distinguons, à la suite de G. Polya, les raisonnements plausibles des raisonnements démonstratifs. Ensuite, nous nous intéressons à certains éléments de logique qui nous paraissent importants au niveau d’une TSUM. Puis, nous analysons la nature de preuves mathématiques à ce stade de l’apprentissage. Enfin, nous dissertons quelque peu sur l’usage des démonstrations dans l’enseignement. Ce travail se termine par deux annexes techniques, relatives respectivement à différents types de syllogismes et à quelques éléments plus formels de logique mathématique. [less ▲]

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See detailMusique et plaisanterie. Ethnographie de trois groupes sociaux (coolooji, ñeeñɓe et mbiruuji) à Djéwol (Mauritanie)
Sow, Aboubakry ULg

Doctoral thesis (2017)

The village of Djéwol (Mauritania) is located on the right bank of the Sénégal river and its' population is estimated to approximately 9000 inhabitants that are split to two communities, the Haalpulaar ... [more ▼]

The village of Djéwol (Mauritania) is located on the right bank of the Sénégal river and its' population is estimated to approximately 9000 inhabitants that are split to two communities, the Haalpulaar and the Soninké who are organinized into hierarchies. Straddling on both communities are the ñeeñɓe (social mediators) and the riimayɓe (servants), who are the main producers and actors of music. Although sometimes they declare themselves to be Haalpulaar, other times, they call themselves Soninké, mainly because of bilingualism and versatility of their music. For this reason, the ñeeñɓe and riimayɓe are conveyed to all manifestations and festivities that punctuate the life of the village. On such occasions, other genres of music are also played by coolooji (social protesters) and the mbiruuji (fighters), both of these being marginal subclasses who are constantly in conflict with the ñeeñɓe. Based on my position of researcher/musian/haalpulaar/dimo (noble) originating from this village and on my personal journey, while using a reflexive method, I will question the rôle and the place in the society of the three actors previously mentioned : The coolooji, the ñeeñɓe and the mbiruuji. Starting with an ethnological description and an anthropological analysis of the different operating modes of yano (pleasantry procedure) – which allow the denɗiraagal (similar to pleasantry) to be set into motion or not – in their articulation of music, it will be a matter of asking ourselves in which way the the coolooji, the ñeeñɓe and the mbiruuji define themselves and contribute to defining others through yano and music. Thus, the first part of this thesis suggests, beyond the presentation of the historical and social context of the community and Djéwol village, adopting a synoptic perspective on the Haalpulaar and Soninké music of the region near the Sénégal river. The second part, however, will focus on the origin of the different types of relations in jiidugal (kin) and of denɗiraagal (related of pleasantry) which proceed by using the yano, as well as the musical art associated with the later. Finally, the last part will be dedicated to analyzing the interactions, conflicting or not, as well as the absence of interactions between the coolooji, the ñeeñɓe and the mbiruuji while highlighting the similarities and the differences between these three significant figures. In conclusion, the situation will be analyzed in the light of the contemporary reconfigurations and of the evolution of the bounds tied between the denɗiraagal and the surrounding social networks. Le village de Djéwol (Mauritanie) se situe sur la rive droite du fleuve Sénégal et compte aujourd’hui 9000 habitants se répartissant en deux communautés, haalpulaar et soninké, fortement hiérarchisées en leur sein. À cheval sur les deux communautés, se trouvent les ñeeñɓe (médiateurs sociaux) et les riimayɓe (serviteurs) qui sont les principaux producteurs et acteurs de musique. Ceux-ci se déclarent tantôt haalpulaar tantôt soninké, notamment en raison de leur bilinguisme et de la polyvalence de leurs musiques. À ce titre, les ñeeñɓe et les riimayɓe sont conviés à toutes les manifestations et festivités qui rythment la vie du village. En ces occasions, d’autres genres de musiques sont également pratiqués par les coolooji (contestataires sociaux) et les mbiruuji (lutteurs), deux « sous-groupes marginaux » qui sont constamment en conflit avec les ñeeñɓe. En m’appuyant, de manière réflexive, sur ma position de chercheur/musicien/haalpulaar/dimo (noble) originaire du village et sur mon parcours, j’interrogerai le rôle et la place dans la société de trois des acteurs mentionnés : les coolooji, les ñeeñɓe et les mbiruuji. À partir de la description ethnographique et de l’analyse anthropologique des divers modes opératoires du yano (procédé de plaisanterie) – qui permettent d’activer ou de désactiver le denɗiraagal, parenté à plaisanterie – dans leur articulation avec la musique, il s’agira de se demander de quelle manière les coolooji, les ñeeñɓe et les mbiruuji se définissent et contribuent à définir autrui à travers le yano et la musique. Ainsi, la première partie de cette thèse proposera, au-delà de la présentation du contexte historique et social de la commune et du village de Djéwol, un regard synoptique sur les musiques haalpulaar et soninké de la région du fleuve Sénégal. La deuxième partie s’intéressera quant à elle à l’origine des différents types de parenté jiidugal (parenté) et de denɗiraagal (parenté à plaisanterie) procédant par le yano, ainsi qu’à l’art musical associé à ce dernier. Enfin, la dernière partie, consacrée à l’analyse des interactions, conflictuelles ou non, et de l’absence d’interactions entre les coolooji, les ñeeñɓe, et les mbiruuji, mettra en évidence les similitudes et les différences entre ces trois figures. La situation sera finalement analysée à la lumière des reconfigurations contemporaines et de l’évolution des liens de denɗiraagal sur les réseaux sociaux. [less ▲]

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See detailModelling of organic Rankine cycle power systems in off-design conditions: an experimentally-validated comparative study
Dickes, Rémi ULg; Dumont, Olivier ULg; Daccord, Rémi et al

in Energy (2017), 123

Because of environmental issues and the depletion of fossil fuels, the world energy sector is undergoing many changes toward increased sustainability. Among the many fields of research and development ... [more ▼]

Because of environmental issues and the depletion of fossil fuels, the world energy sector is undergoing many changes toward increased sustainability. Among the many fields of research and development, power generation from low-grade heat sources is gaining interest and the organic Rankine cycle (ORC) is seen as one of the most promising technologies for such applications. In this paper, it is proposed to perform an experimentally-validated comparison of different modelling methods for the off-design simulation of ORC-based power systems. To this end, three types of modelling paradigms (namely a constant-efficiency method, a polynomial-based method and a semi-empirical method) are compared both in terms of their fitting and extrapolation capabilities. Post-processed measurements gathered on two experimental ORC facilities are used as reference for the models calibration and evaluation. The study is first applied at a component level (i.e. each component is analysed individually) and then extended to the characterization of the entire organic Rankine cycle power systems. Benefits and limi- tations of each modelling method are discussed. The results show that semi-empirical models are the most reliable for simulating the off-design working conditions of ORC systems, while constant-efficiency and polynomial-based models are both demonstrating lack of accuracy and/or robustness. [less ▲]

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See detailTrees and shrubs influence the behaviour of grazing cattle and rumen fermentation
Vandermeulen, Sophie ULg

Doctoral thesis (2017)

Hedgerows and woody strips have been used to enclose fields but declined due to the loss of a direct economic value, abandonment of traditional management techniques and agricultural intensification ... [more ▼]

Hedgerows and woody strips have been used to enclose fields but declined due to the loss of a direct economic value, abandonment of traditional management techniques and agricultural intensification. Nowadays, shrubs and trees on pastures are promoted again through environment-friendly policies and the interest in using them as forage for ruminant increases in both temperate and tropical ecosystems. Woody plants on farmland could yield a wide range of ecosystem services and provide benefits for farmers and their animals such as forage supply to livestock, animal protection against severe weather and reduced parasitic infestation. Moreover, shifts in digestive physiology can be observed that will in turn affect the welfare and the performances of the animal and the production system as a whole. Therefore, in order to contribute to the development of sustainable systems using shrubs and trees as a feed component in its full right, the aim of this work was to investigate the influence of trees and shrubs on the behaviour of grazing cattle and their selectivity towards woody species, and to determine the changes induced by temperate and tropical shrub and tree species on rumen fermentation. Firstly, the behaviour of grazing dairy heifers was recorded during the whole grazing season as well as their selectivity towards temperate woody species in a hedge. It was concluded that having access to a hedge influenced the behaviour of grazing cattle, as the animals ingested woody plants in each season but mostly when the available pasture biomass was lower. The most selected species were Carpinus betulus, Corylus avellana, Cornus sanguinea and Crataegus monogyna. Secondly, the chemical composition, in vitro rumen fermentation profile and protein precipitation capacity (PPC) of the temperate shrub and tree species were measured. The analyses showed that Fraxinus excelsior presented the most interesting profile in terms of chemical composition and in vitro fermentation production. Among the preferred species, C. monogyna and C. avellana produced lower CH4 and the latest had the highest PPC. Thirdly, three newly-developed cultivars of the tropical Desmanthus genus were studied for their effects on in vitro rumen fermentation including potential to reduce CH4. Desmanthus leptophyllus and D. bicornutus had the highest anti-methanogenic potential, and D. bicornutus was more digestible. In conclusion, both temperate and tropical shrub and tree fodder are promising to supplement cattle with good quality forage. Cattle can browse woody species voluntarily, however, further investigations are needed to provide relevant practical recommendations on how to manage this resource adequately in order to balance intake by the animal and regrowth capacity of the plant. The impact of management strategies relying on cutting and preservation should also be assessed. Moreover, benefits of shrubs and trees on pastures beyond the animal feeding and nutrition are still poorly characterized while, in an agroecological perspective, they can contribute to a significant improvement of the sustainability of ruminant production systems. [less ▲]

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See detailIncreased sea ice cover disrupts food web structure in coastal Antarctica
Michel, Loïc ULg; Dubois, Philippe; Eleaume, Marc et al

Conference (2017, March 03)

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice ... [more ▼]

Antarctica currently undergoes strong and contrasted impacts linked with climate change. While the West Antarctic Peninsula is one of the most rapidly warming regions in the world, resulting in sea ice cover decrease, the sea ice cover of East Antarctica unexpectedly tends to increase, possibly in relation with changes in atmospheric circulation. Sea ice is a major environmental driver in Antarctica, and changes in sea ice cover are likely to influence benthic food web structure through several processes (modifications of benthic-pelagic coupling, disruption of benthic production and/or modifications of benthic community structure and therefore resource availability for benthic consumers). To date, regions where sea ice cover is decreasing have received more attention than regions where it is increasing. Here, on the other hand, we studied shallow (0-20 m) benthic food web structure on the coasts of Petrels Island (Adélie Land, East Antarctica) during an event of unusually high spatial and temporal (two successive austral summers without seasonal break-up) sea ice cover. Using time-tested integrative trophic markers (stable isotope ratios of carbon, nitrogen and sulfur) and state-of-the-art data analysis tools (bayesian ecological models), we studied the structure of the food web associated to benthic macroinvertebrates communities. In total, 28 macroinvertebrate taxa spanning most present animal groups (sponges, sea anemones, nemerteans, nematods, sipunculids, sessile and mobile polychaetes, gastropods, bivalves, pycnogonids, crustaceans, sea stars, sea urchins, brittle stars and sea cucumbers) and functional guilds (grazers, deposit feeders, filter feeders, predators, scavengers) were investigated. Our results indicate that the absence of seasonal sea ice breakup deeply influences coastal benthic food webs in Antarctica. We recorded marked differences from literature data, both in terms of horizontal (i.e. primary producers and resources supporting animal populations) and vertical (i.e. trophic level of the studied consumers) structure of the food web. Overall, sympagic (sea-ice associated) algae dominated the diet of many important consumers, and the trophic levels of invertebrates were low, suggesting omnivore consumers relied less on predation and/or scavenging than in normal environmental conditions. Surprisingly, few animals seemed to feed on the extremely abundant benthic biofilm, whose exceptional development was also presumably linked with the peculiar sea ice conditions. Interpretation of data was complicated by the peculiar ecophysiological features of Antarctic invertebrates, whose very low metabolic rates could be associated to low tissue turnover. However, comparison of data obtained in the austral summers of 2013-2014 (first year without seasonal breakup) and 2014-2015 (second year without seasonal breakup) clearly showed that the observed trends were linked with actual temporal changes in invertebrate feeding habits rather than with other potential ecological drivers. Our results provide insights about how Antarctic benthic consumers, which have evolved in an extremely stable environment, might adapt their feeding habits in response to sudden man-driven changes in environmental conditions and trophic resource availability. They also show that local and/or global trends of sea ice increase in Antarctica could cause strong changes in food web structure and therefore impact zoobenthic communities. This reinforces the view that, no matter their overall direction (i.e. increase or decrease), fluctuations in sea ice cover are likely to influence Antarctic benthic ecosystems' structure and functioning. [less ▲]

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See detailWASP-South transiting exoplanets: WASP-130b, WASP-131b, WASP-132b, WASP-139b, WASP-140b, WASP-141b & WASP-142b
Hellier, Coel; Anderson, D. R.; Collier Cameron, A. et al

in Monthly Notices of the Royal Astronomical Society (2017), 465

We describe seven new exoplanets transiting stars of V = 10.1 to 12.4. WASP-130b is a "warm Jupiter" having an orbital period of 11.6 d, the longest yet found by WASP. It transits a V = 11.1, G6 star with ... [more ▼]

We describe seven new exoplanets transiting stars of V = 10.1 to 12.4. WASP-130b is a "warm Jupiter" having an orbital period of 11.6 d, the longest yet found by WASP. It transits a V = 11.1, G6 star with [Fe/H] = +0.26. Warm Jupiters tend to have smaller radii than hot Jupiters, and WASP-130b is in line with this trend (1.23 Mjup; 0.89 Rjup). WASP-131b is a bloated Saturn-mass planet (0.27 Mjup; 1.22 Rjup). Its large scale height coupled with the V = 10.1 brightness of its host star make the planet a good target for atmospheric characterisation. WASP-132b is among the least irradiated and coolest of WASP planets, being in a 7.1-d orbit around a K4 star. It has a low mass and a modest radius (0.41 Mjup; 0.87 Rjup). The V = 12.4, [Fe/H] = +0.22 star shows a possible rotational modulation at 33 d. WASP-139b is the lowest-mass planet yet found by WASP, at 0.12 Mjup and 0.80 Rjup. It is a "super-Neptune" akin to HATS-7b and HATS-8b. It orbits a V = 12.4, [Fe/H] = +0.20, K0 star. The star appears to be anomalously dense, akin to HAT-P-11. WASP-140b is a 2.4-Mjup planet in a 2.2-d orbit that is both eccentric (e = 0.047) and with a grazing transit (b = 0.93) The timescale for tidal circularisation is likely to be the lowest of all known eccentric hot Jupiters. The planet's radius is large (1.4 Rjup), but uncertain owing to the grazing transit. The host star is a V = 11.1, [Fe/H] = +0.12, K0 dwarf showing a prominent 10.4-d rotational modulation. The dynamics of this system are worthy of further investigation. WASP-141b is a typical hot Jupiter, being a 2.7 Mjup, 1.2 Rjup planet in a 3.3-d orbit around a V = 12.4, [Fe/H] = +0.29, F9 star. WASP-142b is a typical bloated hot Jupiter (0.84 Mjup, 1.53 Rjup) in a 2.1-d orbit around a V = 12.3, [Fe/H] = +0.26, F8 star. [less ▲]

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See detailINVESTIGATION DE LA QUALITE D’ANTIBIOTIQUES A BASE D'AMOXICILLINE DANS LE CADRE DE LA SURVEILLANCE DU MARCHE OFFICIEL ET PERIPHERIQUE DE QUELQUES VILLES DE LA R.D. CONGO
Kalenda Tshilombo, Nicodème ULg; Ciza Hamuli, Patient ULg; Mavungu Landu, Don Jethro ULg et al

Poster (2017, March)

Drug counterfeiting is a sad and worrisome reality, especially in developing countries where quality control is not effective and sometimes not existing at all despite political will of governments. The ... [more ▼]

Drug counterfeiting is a sad and worrisome reality, especially in developing countries where quality control is not effective and sometimes not existing at all despite political will of governments. The consequences are harmful in particular for substandard medicines that pose more threats to populations in those countries due to their direct negative impact on patients such as failure of medical treatment including development of drug resistance and even death. Socio-economic consequences and negative reputation concerning the pharmaceutical industry are also observed. Unfortunately accurate detailed data on such medicines are not easy to obtain. Most of the time available data are often estimated from case reports or studies carried out in a specific area and during a defined period.Health authorities’ in the Democratic Republic of Congo are trying to identify this scourge by set up several strategies to fight against. One of them is built on the best knowledge of drugs from several horizons through the assessment of their quality to allow appropriate measurement. In this context, we have focused our study towards amoxicillin alone and/or combined with potassium clavulanate since it is one the very used medicines in pediatric medications. The formulations are powder for suspension. Two analytical methods were developed based on the USP monography, applying isocratic liquid chromatography. Prior to their application in routine, we evaluated the suitability of these methods through validation applying the accuracy profile of total error. Since it was planned to transfer the methods to DRC, several operating factors were taken into account namely operator, day and equipment. Interesting results were obtained in terms of trueness (relative biases below than 2.3%), precision (RSD of Intermediate precision below 2.8%), accuracy (beta-expectation tolerance intervals between -6.0% and 3.8%) for the concentration levels of interest. The latter were able to allow monitoring the quality of the two active ingredients here above in the 65 samples from Congolese market. They were collected in Kinshasa, Lubumbashi, Matadi and Kolwezi at official and non-official medicines distributors, in peripheral area. The dramatic results obtained confirm that substandard and counterfeit medicines remain a crucial problem on public health in low-income countries. Appropriate measures are really needed to set up the drug quality improvement. [less ▲]

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See detailThe origin of CIMP or how to increase international contacts between Paleozoic palynologists during the second part of last century.
Streel, Maurice ULg

in Commission internationale de la microflore du Paléozoïque CIMP Newsletter (2017), 86

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See detailDevelopment of Specifications and Performance Criteria for Surface Preparation Based on Issues Related to Bond Strength
Bissonnette, Benoît; Courard, Luc ULg; Garbacz, Andrzej et al

Report (2017)

In addition to the development of a satisfactory test procedure and recommendations to improve the overall quality of concrete repair works, the authors of this proposal intend to collaborate with various ... [more ▼]

In addition to the development of a satisfactory test procedure and recommendations to improve the overall quality of concrete repair works, the authors of this proposal intend to collaborate with various representatives from public agencies and from the industry to facilitate technological transfer. Presentations will be made in conferences and workshops in North America and Europe. At the end of the project, the results shall include two MSc theses and at least two papers in major journals, such as Concrete International or ACI Materials Journal. Also, the project should provide the basis towards a standard procedure for the evaluation of superficial cohesion of concrete, in relation with surface preparation and concrete removal techniques. Finally, recommendations and specifications could be incorporated in future versions of the ACI-ICRI Manual of Concrete Repairs as well as in DOT’s specifications. [less ▲]

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See detailConstraining the efficiency of angular momentum transport with asteroseismology of red giants: the effect of stellar mass
Eggenberger, P.; Lagarde, N.; Miglio, A. et al

in Astronomy and Astrophysics (2017), 599

Context: Constraints on the internal rotation of red giants are now available thanks to asteroseismic observations. Preliminary comparisons with rotating stellar models indicate that an undetermined ... [more ▼]

Context: Constraints on the internal rotation of red giants are now available thanks to asteroseismic observations. Preliminary comparisons with rotating stellar models indicate that an undetermined additional process for the internal transport of angular momentum is required in addition to purely hydrodynamic processes. Aims: We investigate how asteroseismic measurements of red giants can help us characterize the additional transport mechanism. Methods: We first determine the efficiency of the missing transport mechanism for the low-mass red giant KIC 7341231 by computing rotating models that include an additional viscosity corresponding to this process. We then discuss the change in the efficiency of this transport of angular momentum with the mass, metallicity and evolutionary stage. Results: In the case of the low-mass red giant KIC 7341231, we find that the viscosity corresponding to the additional mechanism is constrained to the range 1 x 10^3 - 1.3 x 10^4 cm^2/s. This constraint on the efficiency of the unknown additional transport mechanism during the post-main sequence is obtained independently of any specific assumption about the modelling of rotational effects during the pre-main sequence and the main sequence (in particular, the braking of the surface by magnetized winds and the efficiency of the internal transport of angular momentum before the post-main-sequence phase). When we assume that the additional transport mechanism is at work during the whole evolution of the star together with a solar-calibrated braking of the surface by magnetized winds, the range of nu_add is reduced to 1 - 4 x 10^3 cm^2/s. In addition to being sensitive to the evolutionary stage of the star, we show that the efficiency of the unknown process for internal transport of angular momentum increases with the stellar mass. [less ▲]

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See detailLocal Identification of Voltage Instability from Load Tap Changer Response
Weckesser, Johannes ULg; Papangelis, Lampros ULg; Vournas, Costas et al

in Sustainable Energy, Grids and Networks (2017)

This paper presents a local long-term voltage instability monitoring method, which is suitable for on-line applications. The proposed extended-time Local Identification of Voltage Emergency Situations ... [more ▼]

This paper presents a local long-term voltage instability monitoring method, which is suitable for on-line applications. The proposed extended-time Local Identification of Voltage Emergency Situations (eLIVES) method is a significantly modified version of the previously presented LIVES method. The new method is not bound to assessing system response over a predefined LTC tapping period. This allows handling LTCs with variable delays, as well as events taking place during the tapping sequence impacting the distribution voltages. For that purpose, eLIVES applies recursive least square fitting to acquired distribution voltage measurements and a new set of rules to detect a voltage emergency situation. The effectiveness of the eLIVES method is presented on the IEEE Nordic test system for voltage stability and security assessment. [less ▲]

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See detailLiens entre mathématiques et jeux
Bair, Jacques ULg

E-print/Working paper (2017)

Le présent travail se compose de plusieurs parties. En premier lieu, nous définissons le concept général de jeu et présentons quelques mathématiciens célèbres, de toutes époques, qui étaient (ou sont ... [more ▼]

Le présent travail se compose de plusieurs parties. En premier lieu, nous définissons le concept général de jeu et présentons quelques mathématiciens célèbres, de toutes époques, qui étaient (ou sont encore) des adeptes de jeux mathématiques. Ensuite, nous établissons une typologie des jeux mathématiques. Une deuxième partie est consacrée à l’intervention des jeux dans l’enseignement des mathématiques. Nous donnons divers avantages des activités ludiques en classe, mais également des objections relatives à leur usage à des fins pédagogiques. Nous nous demandons aussi comment sélectionner un jeu pour des élèves et exhibons des exemples concrets de jeux exploitables en classe. Ce travail se termine par une bibliographie sur le sujet, ainsi que par une annexe composée de diapositives présentées lors d’un exposé réalisé à l’Université du Luxembourg dans le cadre de la Formation Pédagogique (FOPED) : nous y décrivons brièvement différentes épreuves ludiques proposées ces dernières années à des élèves de l’enseignement secondaire en France, Belgique et au Luxembourg. [less ▲]

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See detail"888" Tweets on the Art and Science of Internet-Based Investing
Choffray, Jean-Marie ULg

E-print/Working paper (2017)

Here we are! "888" Tweets on The Art and Science of Investing to “show you the way”, to share some observations on the evolution of the world, the behavior of the financial markets, and to illustrate the ... [more ▼]

Here we are! "888" Tweets on The Art and Science of Investing to “show you the way”, to share some observations on the evolution of the world, the behavior of the financial markets, and to illustrate the key heuristics that I learned over the last twenty years. As, without any doubt, I am no Warren Buffett, feel free to disagree and develop you own “theory” of investing. Painful and solitary work... Success is at that price! And, based on what I did - and did not! - achieve, it shouldn’t be hard to do much better... That’s my wish for you! [less ▲]

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See detailSeven temperate terrestrial planets around the nearby ultracool dwarf star
Gillon, Michaël ULg; Triaud, Amaury; Demory, Brice-Olivier et al

in Nature (2017), 542

One focus of modern astronomy is to detect temperate terrestrial exoplanets well-suited for atmospheric characterisation. A milestone was recently achieved with the detection of three Earth-sized planets ... [more ▼]

One focus of modern astronomy is to detect temperate terrestrial exoplanets well-suited for atmospheric characterisation. A milestone was recently achieved with the detection of three Earth-sized planets transiting (i.e. passing in front of) a star just 8% the mass of the Sun 12 parsecs away. Indeed, the transiting configuration of these planets combined with the Jupiter-like size of their host star - named TRAPPIST-1 - makes possible indepth studies of their atmospheric properties with current and future astronomical facilities. Here we report the results of an intensive photometric monitoring campaign of that star from the ground and with the Spitzer Space Telescope. Our observations reveal that at least seven planets with sizes and masses similar to the Earth revolve around TRAPPIST-1. The six inner planets form a near-resonant chain such that their orbital periods (1.51, 2.42, 4.04, 6.06, 9.21, 12.35 days) are near ratios of small integers. This architecture suggests that the planets formed farther from the star and migrated inward. The seven planets have equilibrium temperatures low enough to make possible liquid water on their surfaces. [less ▲]

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See detailComment le changement climatique influence-t-il la croissance du hêtre (Fagus sylvatica L.) le long du gradient bioclimatique de la Belgique ? Une approche dendroécologique.
Latte, Nicolas ULg

Doctoral thesis (2017)

Health anomalies (e.g., worsening crown conditions) on beech (Fagus sylvatica L.) observed throughout Europe since the 1990s have raised growing concerns among foresters, particularly about the future ... [more ▼]

Health anomalies (e.g., worsening crown conditions) on beech (Fagus sylvatica L.) observed throughout Europe since the 1990s have raised growing concerns among foresters, particularly about the future behavior of the species in the face of climate change. This PhD research examined the relationship between beech and its environment in the context of global changes using dendroecology, combination of dendrochronology and forest ecology. The radial growth was used to evaluate the effects of global changes, particularly climate change, on beech development and vitality over time along a bioclimatic gradient in Belgium. Various analyses were carried out using dendrochronological tools (pointer years, mean sensitivity, growth-climate correlation, etc.) and modeling approaches (linear and non-linear mixed models, partial least squares regression, etc.) considering several scales: tree, stand and region. Results show that climate predominantly influenced beech growth since the mid-20th century and did so rather uniformly across Belgium. Beech mean sensitivity increased mainly in response to the higher frequency and intensity of summer heat waves and spring droughts. Isolated but pronounced annual growth reductions induced a gradual diminution of mean growth. The increasing influence of climate progressively concealed the effect of local site growing conditions inducing strong between-sites synchronization along the bioclimatic gradient. Increasing mean sensitivity and decreasing mean growth were more pronounced in lowlands than in uplands, and for a given site, older trees are more affected than younger ones. Although mean sensitivity increases and mean growth decreases naturally with age, the climate change effect was much more important than the age effect. Furthermore, within a tree, along the main stem, climate sensitivity slightly decreased from breast height to crown base and strongly increased from crown base to tree top. These results were interpreted based on ecophysiological knowledge of beech. The influences of silviculture, soil compaction and nitrogen deposition (as part of atmospheric pollution) as well as the consequences of the past and future climate change on beech were discussed. Comparisons with other studies in Europe highlighted that beech is affected on a large part of its natural distribution range (except in high altitude and high latitude). Contrary to what one might think, beech is not only affected in the southern limit (Mediterranean). Although growing conditions are more favorable in Belgium, beech has also more to lose. Beech has coped with global change up to now. Although its climate sensitivity increased and its mean growth decreased, diebacks observed these last years in Belgium were scarce and generally scattered. However, considering the upcoming climate change, the phytosanitary risk will undeniable increased. Forest policy should now integrate that risk and prepare managers to anticipate and prevent it. [less ▲]

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See detailTroubles de la Régulation du Traitement sensoriel
SCHOLL, Jean-Marc ULg

Conference given outside the academic context (2017)

Actuellement, peu de médecins et de psychologues connaissent les « Troubles de la Régulation Sensorielle ». Or, chez le petit enfant, ils peuvent fortement influencer sa psychologie, ses comportements et ... [more ▼]

Actuellement, peu de médecins et de psychologues connaissent les « Troubles de la Régulation Sensorielle ». Or, chez le petit enfant, ils peuvent fortement influencer sa psychologie, ses comportements et altérer son fonctionnement. Ces difficultés peuvent demeurer chez l’adulte et interférer sur son fonctionnement quotidien. Ainsi, il est utile de former le réseau des professionnels, particulièrement le réseau de la santé mentale de l’enfance et le réseau des crèches et de l’enseignement maternel. Le diagnostic d'un Trouble de la Régulation du traitement Sensoriel est réalisé à partir de l'anamnèse et de la description de l'enfant dans ses différents milieux de vie. Afin de réaliser un dépistage, cette présentation donne une sémiologie précise permettant de reconnaître les signes et symptômes chez l'enfant et chez l'adulte. Il est également utile de systématiquement rechercher s'il n'y a pas d'autres difficultés et comorbidités s'ajoutant à ce premier diagnostic. Le module de formation ici présenté donne divers points de repères : I. Données générales : 1) Prévalence 2) Enjeu de santé publique 3) Vignette Clément 4) Vignette Aude 5) Voies d’entrée des stimuli sensoriels 6) Traitement central de l’information 7) Régulation sensorielle 8) Altération du développement de l’enfant II. Du dépistage au diagnostic : 1) Dépistage et diagnostic 2) Dépistage : hyper- /hypo-sensibilités 3) Dépistage : Exemples d’hypersensibilités 4) Dépistage : Exemples d’hyposensibilités [less ▲]

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See detailTre segnalazioni su Sciascia. Città, solitudini, saggismo e invenzione.
Curreri, Luciano ULg

Article for general public (2017)

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See detailEnergy Efficiency in the Romanian Residential Building Stock: A Literature Review
Muresan, Adina Ana; Attia, Shady ULg

in Renewable and Sustainable Energy Reviews (2017), 74

The building sector in Romania is dominated by residential buildings that are old and have poor thermal performance. As member of the European Union, Romania has to reach the objectives imposed by the ... [more ▼]

The building sector in Romania is dominated by residential buildings that are old and have poor thermal performance. As member of the European Union, Romania has to reach the objectives imposed by the Directive 2009/28/EC and to fulfill the requirements of the Energy Performance of Buildings Directive (EPBD) by year 2020. To reach the 2020 objectives, the old buildings from the Romanian building stock should be rehabilitated and the new buildings should be designed according to the latest thermal performance characteristics. The following paper presents the literature review of building energy performance in Romania. The purpose of the literature review analysis is to provide an overview on current building energy efficiency in Romania. The paper also presents future perspectives on implementation of high performance buildings such as the Passive House (PH), nearly Zero Energy Buildings (nZEB) and Net Zero Energy Buildings (NZEB). The reviewed publications and case studies are classified under three categories: policy and regulations, technology and feasibility. Finally, the paper presents a holistic perspective on the Strength, Weakness, Opportunities and Threats (SWOTs) of energy efficiency in Romania's residential building sector. [less ▲]

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