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See detailA meta-analysis of isotopic compositions of North Sea marine mammals
Damseaux, France ULg; Lepoint, Gilles ULg; Das, Krishna ULg

Conference (2017, March 03)

For over a decade, the North Sea has been undergoing significant changes due to global changes and overfishing. We conducted meta-analyses of previously published data on marine mammals sampled in the ... [more ▼]

For over a decade, the North Sea has been undergoing significant changes due to global changes and overfishing. We conducted meta-analyses of previously published data on marine mammals sampled in the North Sea to test the competition for food sources and spatial variations. The overall objective of this study was to assess the potential trophic changes of the grey seal, the harbour seal and the harbour porpoise. Data included δ13C and δ15N values measured in blood cells and muscles from the three species. SIBER, a trophic niche overlap quantification approach, highlighted potential competition between marine mammal species. The ellipse drawn for harbour seal data showed the highest δ15N values, reflecting its trophic position at the top of the food web. But the ellipse overlapping between the harbour seal and the grey seal of Germany was very important, showing a potential strong competition for food sources may be due to the overfishing. The harbour porpoise displayed a lower trophic position and a wide range of δ13C and δ15N values compared to harbour seal and grey seal as seen from its extended ellipse size. This may be due to a more opportunistic behaviour following the decline of some fish population in the North Sea. Surprisingly a group of grey seals sampled in Scotland present a very small ellipse size, presumably more selective in their prey choice, and showed the lowest δ15N values. Caution should be taken before comparing the trophic position of the groups of grey seals as the baseline differed between the two sampling areas. Low nitrates concentrations, higher latitudes, colder temperatures, deeper waters and rocky soils of the Scotland’s coasts of the North Sea cause a stratification phenomenon of the water column explaining the lower δ15N baseline in this area and so the spatial variation between these two groups of grey seals living in the North Sea. [less ▲]

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See detailExploiting random projections and sparsity with random forests and gradient boosting methods - Application to multi-label and multi-output learning, random forest model compression and leveraging input sparsity
Joly, Arnaud ULg

Doctoral thesis (2017)

Within machine learning, the supervised learning field aims at modeling the input-output relationship of a system, from past observations of its behavior. Decision trees characterize the input-output ... [more ▼]

Within machine learning, the supervised learning field aims at modeling the input-output relationship of a system, from past observations of its behavior. Decision trees characterize the input-output relationship through a series of nested ``if-then-else'' questions, the testing nodes, leading to a set of predictions, the leaf nodes. Several of such trees are often combined together for state-of-the-art performance: random forest ensembles average the predictions of randomized decision trees trained independently in parallel, while tree boosting ensembles train decision trees sequentially to refine the predictions made by the previous ones. The emergence of new applications requires scalable supervised learning algorithms in terms of computational power and memory space with respect to the number of inputs, outputs, and observations without sacrificing accuracy. In this thesis, we identify three main areas where decision tree methods could be improved for which we provide and evaluate original algorithmic solutions: (i) learning over high dimensional output spaces, (ii) learning with large sample datasets and stringent memory constraints at prediction time and (iii) learning over high dimensional sparse input spaces. A first approach to solve learning tasks with a high dimensional output space, called binary relevance or single target, is to train one decision tree ensemble per output. However, it completely neglects the potential correlations existing between the outputs. An alternative approach called multi-output decision trees fits a single decision tree ensemble targeting simultaneously all the outputs, assuming that all outputs are correlated. Nevertheless, both approaches have (i) exactly the same computational complexity and (ii) target extreme output correlation structures. In our first contribution, we show how to combine random projection of the output space, a dimensionality reduction method, with the random forest algorithm decreasing the learning time complexity. The accuracy is preserved, and may even be improved by reaching a different bias-variance tradeoff. In our second contribution, we first formally adapt the gradient boosting ensemble method to multi-output supervised learning tasks such as multi-output regression and multi-label classification. We then propose to combine single random projections of the output space with gradient boosting on such tasks to adapt automatically to the output correlation structure. The random forest algorithm often generates large ensembles of complex models thanks to the availability of a large number of observations. However, the space complexity of such models, proportional to their total number of nodes, is often prohibitive, and therefore these modes are not well suited under stringent memory constraints at prediction time. In our third contribution, we propose to compress these ensembles by solving a L1-based regularization problem over the set of indicator functions defined by all their nodes. Some supervised learning tasks have a high dimensional but sparse input space, where each observation has only a few of the input variables that have non zero values. Standard decision tree implementations are not well adapted to treat sparse input spaces, unlike other supervised learning techniques such as support vector machines or linear models. In our fourth contribution, we show how to exploit algorithmically the input space sparsity within decision tree methods. Our implementation yields a significant speed up both on synthetic and real datasets, while leading to exactly the same model. It also reduces the required memory to grow such models by exploiting sparse instead of dense memory storage for the input matrix. [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 detailLinking Forest Cover to Water Quality: A Multivariate Analysis of Large Monitoring Datasets
Brogna, Delphine; Michez, Adrien ULg; Jacobs, Sander et al

in Water (2017), 9(3), 176

Forested catchments are generally assumed to provide higher quality water. However, this hypothesis must be validated in various contexts as interactions between multiple land use and land cover (LULC ... [more ▼]

Forested catchments are generally assumed to provide higher quality water. However, this hypothesis must be validated in various contexts as interactions between multiple land use and land cover (LULC) types, ecological variables and water quality variables render this relationship highly complex. This paper applies a straightforward multivariate approach on a typical large monitoring dataset of a highly managed and densely populated area (Wallonia, Belgium; 10-year dataset), quantifying forest cover effects on nine physico-chemical water quality variables. Results show that forest cover explains about one third of the variability of water quality and is positively correlated with higher quality water. When controlling for spatial autocorrelation, forest cover still explains 9% of water quality. Unlike needle-leaved forest cover, broad-leaved forest cover presents an independent effect from ecological variables and explains independently 4.8% of water quality variability while it shares 5.8% with cropland cover. This study demonstrates clear independent effects of forest cover on water quality, and presents a method to tease out independent LULC effects from typical large multivariate monitoring datasets. Further research on explanatory variables, spatial distribution effects and water quality datasets could lead to effective strategies to mitigate pollution and reach legal targets. [less ▲]

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See detailUn regard comparatif sur les régionalismes africain et latino-américain
Santander, Sébastian ULg

in Interventions Economiques = Papers in Political Economy (2017)

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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 detailCorde à Corde - Le duo Philippe AERTS ( contrebasse) - Raphaëlle BROCHET (chant) - interview
Sacré, Robert ULg

E-print/Working paper (2017)

Interview des 2 musiciens sur leur carrière et sur la sortie de l'album KALAMAMBA chez Igloo Records ( IGL282)

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See detailCan science explain consciousness? Lessons from coma and related states
Martial, Charlotte ULg

Conference (2017, March)

Understanding consciousness remains one of the greatest mysteries for science to solve. How do our brains work? How can we know if some patients in coma have any consciousness left and how could we ... [more ▼]

Understanding consciousness remains one of the greatest mysteries for science to solve. How do our brains work? How can we know if some patients in coma have any consciousness left and how could we communicate with them? What are near-death experiences? What is brain death? What happens in our brains during dreaming, hypnosis or meditation? At present, nobody understands how matter (our trillions of neural connections) becomes perception and thought. We will here briefly review some neurological facts on consciousness and impaired consciousness. Thanks to recent advances in (neuroimaging) technology, the mapping of conscious perception and cognition in health (e.g., conscious waking, sleep, dreaming, hypnosis, meditation, sleepwalking and anesthesia) and in disease (e.g., coma, near-death, “vegetative” state, seizures, hallucinations etc) is providing exiting new insights into the functional neuroanatomy of human consciousness. Our perception of the outside world (sensory awareness; what we see, hear, etc.) and our awareness of an inner world (self-awareness; the little "voice" inside that "speaks" to ourselves) seemingly depend on two separate networks we could recently identify. Philosophers might argue that the subjective aspect of the mind will never be sufficiently accounted for by the objective methods of reductionistic science. We here prefer a more pragmatic approach and remain naively optimistic that technological advances might ultimately lead to an understanding of the neural substrate of human consciousness. [less ▲]

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See detailCouper et coller ? Une anecdote dans les manuscrits avestiques : l’exemple de K5 et K6
Ferrer-Losilla, Joan Josep ULg

in Estudios Iranios y Turanios. fәrā amәṣ̌ā spәṇtā gāθā̊ gə̄uruuāin Homenaje a Helmut Humbach en su 95º aniversario (2017), 3(1), 59-66

The present paper analyses an anecdotic case of “copy and paste” between two manuscripts belonging to two different lines of the Zoroastrian manuscript transmission: the Pahlavi exegetical (ms. K5) and ... [more ▼]

The present paper analyses an anecdotic case of “copy and paste” between two manuscripts belonging to two different lines of the Zoroastrian manuscript transmission: the Pahlavi exegetical (ms. K5) and the Sanskrit exegetical (ms. K6). I have found that a lost fragment of K5 is pasted, in fact, in K6 in a context hardly comprehensible. [less ▲]

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See detailMusic 4 A While - entretien avec deux des musiciens de ce projet
Sacré, Robert ULg

E-print/Working paper (2017)

Entretien avec Jean François Foliez ( clarinette) et Johan Dupont, pianiste, arrangeur et concepteur du projet Music 4 A While paru chez Igloo Records

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See detailInterview pour LARSEN, le magazine de l'actualité musicale en Fédération Wallonie-Bruxelles
Sacré, Robert ULg

in Jacques Prouvost (Ed.) LARSEN - Zoom Le Blues du Belge (2017)

Histoire du blues en Belgique

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See detailCreative Playground ( Jean François Foliez) - vidéo "Home" ( composition Johan Dupont)
Sacré, Robert ULg

E-print/Working paper (2017)

Spectacle "Creative Playground 2017" Théâtre de Liège, 4 mars 2017; en vidéo "Home" une composition du pianiste Johan Dupont

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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 detailSeasonal plasticity of auditory saccular sensitivity in “sneaker” type II male plainfin midshipman fish, Porichthys notatus
Bhandiwad, Ashwin A.; Whitchurch, Elizabeth A.; Colleye, Orphal ULg et al

in Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural and Behavioral Physiology (2017), 203(3), 211-222

Adult female and nesting (type I) male midshipman fish (Porichthys notatus) exhibit an adaptive form of auditory plasticity for the enhanced detection of social acoustic signals. Whether this adaptive ... [more ▼]

Adult female and nesting (type I) male midshipman fish (Porichthys notatus) exhibit an adaptive form of auditory plasticity for the enhanced detection of social acoustic signals. Whether this adaptive plasticity also occurs in “sneaker” type II males is unknown. Here, we characterize auditory-evoked potentials recorded from hair cells in the saccule of reproductive and non-reproductive “sneaker” type II male midshipman to determine whether this sexual phenotype exhibits seasonal, reproductive state-dependent changes in auditory sensitivity and frequency response to behaviorally relevant auditory stimuli. Saccular potentials were recorded from the middle and caudal region of the saccule while sound was presented via an underwater speaker. Our results indicate saccular hair cells from reproductive type II males had thresholds based on measures of sound pressure and acceleration (re. 1 μPa and 1 ms−2, respectively) that were ~8–21 dB lower than non-reproductive type II males across a broad range of frequencies, which include the dominant higher frequencies in type I male vocalizations. This increase in type II auditory sensitivity may potentially facilitate eavesdropping by sneaker males and their assessment of vocal type I males for the selection of cuckoldry sites during the breeding season. [less ▲]

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See detailPosidonies : Lire dans les prairies sous-marines
Abadie, Arnaud ULg; Gobert, Sylvie ULg; Pergent, Gérard

Article for general public (2017)

Les “feuilles” qui s’amoncèlent sur les plages de Méditerranée sont le souvenir échoué des luxuriantes prairies sous-marines qui tapissent les fonds. C’est un écosystème fragile dont dépend un grand ... [more ▼]

Les “feuilles” qui s’amoncèlent sur les plages de Méditerranée sont le souvenir échoué des luxuriantes prairies sous-marines qui tapissent les fonds. C’est un écosystème fragile dont dépend un grand nombre d’espèces : les chercheurs doivent apprendre à “lire” les fonds pour identifier les menaces qui pèsent sur la posidonie. [less ▲]

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See detailLaos, Demos, Ethnos. Le peuple a bon dos
Jacquemain, Marc ULg

Article for general public (2017)

Si le républicanisme français est si obsédé par le "visible" et "l'invisible" dans l'espace public, c'est parce qu'il confond l'universalisme idéal de sa devise et le particularisme de ses pratiques ... [more ▼]

Si le républicanisme français est si obsédé par le "visible" et "l'invisible" dans l'espace public, c'est parce qu'il confond l'universalisme idéal de sa devise et le particularisme de ses pratiques réelles. La critique s'inspire de celle de Cécile Laborde dans "Critical Republicanism". [less ▲]

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See detailEtude de la composition chimique et de l’activité antioxydante des différents extraits de la Lavande dentée (Lavandula dentata)
Bettaieb Rebey, I.; Bourgou, S.; Saidani Tounsi, M. et al

in Journal of New Sciences Agri & Biotech (2017), 39(2), 2096-2105

In this study, Lavandula dentata organs (roots, stems and leaves) were investigated for their essential oils, total phenolics, flavonoids contents and antioxidant activities. Essential oil yields were 0 ... [more ▼]

In this study, Lavandula dentata organs (roots, stems and leaves) were investigated for their essential oils, total phenolics, flavonoids contents and antioxidant activities. Essential oil yields were 0.22% in roots, 0.68 % in stems and 0.89 % in flowers. Major components of the oils were β-ocimene, limonene and 1,8 cineol in roots, stems and leaves and flowers, respectively. In all organs, total phenolics content ranged from 42.57 to 16.17 mg gallic acid equivalents per gram of dry weight (mg GAE/g DW).The antioxidant activities of Lavandula dentata extracts obtained from the three organs were assessed using two tests (DPPH and reducing power). The root extract was strongly effective as DPPH radical scavenger and reducing agent. Thus, the identification of individual target polyphenolic compounds of roots was performed by RP-HPLC. The major phenolic compound detected in roots was rosmarinic acid. This activity was high enough for the plant to be a new and natural source of strongly antioxidant substances for use as natural additives in food and pharmaceutical industry. [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 detailComment les vidéastes gagnent-ils leur vie sur Youtube ?
Krywicki, Boris ULg

in Culture, le Magazine Culturel de l'Université de Liège (2017)

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