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See detailMacroevolutionary patterns in sea breams, emperors and allies (Sparoidea, Acanthomorpha)
Santini, Francesco; Olivier, Damien ULg; Frederich, Bruno ULg

Poster (2017, January 07)

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See detailPollen nutrients better explain bumblebee colony development than pollen diversity
Moerman, Romain; Vanderplanck, Maryse ULg; Fournier, Denis et al

in Insect Conservation and Diversity (2017)

1. Bumblebees are valuable pollinators of numerous wild and cultivated plants. They can forage on variable pollen resources. As some pollen species lack particular nutrients or have global low nutritional ... [more ▼]

1. Bumblebees are valuable pollinators of numerous wild and cultivated plants. They can forage on variable pollen resources. As some pollen species lack particular nutrients or have global low nutritional quality, it has been suggested that bumblebees mix their pollen incomes to ensure a global balanced diet. The hypothesis that a mixed pollen diet better supports bumblebee colony development than a single pollen diet has been poorly explored. 2. We compared the impact of mono-, di- and trifloral diets on microcolony development of Bombus terrestris using three pollen resources with different nutrient contents (Cytisus scoparius, Erica sp. and Sorbus aucuparia) as well as their mixes. Nine parameters (e.g. pollen efficacy: total weight of larvae/total weight of pollen collection) were used to compare the microcolony performances. Moreover, we measured the influence of the pollen diversity and nutritional composition on relevant parameters. 3. We showed that microcolonies can potentially better develop on mixed pollen diets, but single pollen diet can also be as good as mixed pollen diet. Moreover, the sterol concentration appeared as a key factor to establish the impact of a pollen diet on the bumblebee colony development. 4. This study reveals that diverse pollen diet does not necessary equate with good colony development and supports the importance of selecting floral resources by considering their nutrient contents for bee conservation management. [less ▲]

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See detailPatterns of body size and shape diversification in marine angelfishes (Pomacanthidae)
Frederich, Bruno ULg; Santini, Francesco; Konow, Nicolai et al

Conference (2017, January 06)

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See detailCompte rendu de Lavocat (Françoise), Fait et fiction, Paris, Seuil, "Poétique", 2016, 618p.
Huppe, Justine ULg

in COnTEXTES : Revue de Sociologie de la Littérature (2017)

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See detailSegregation and pattern formation in dilute granular media under microgravity conditions
Opsomer, Eric ULg; Noirhomme, Martial ULg; Vandewalle, Nicolas ULg et al

in NPJ Microgravity (2017), 3

Space exploration and exploitation face a major challenge: the handling of granular materials in low-gravity environments. Indeed, grains behave quite differently in space than on Earth, and the ... [more ▼]

Space exploration and exploitation face a major challenge: the handling of granular materials in low-gravity environments. Indeed, grains behave quite differently in space than on Earth, and the dissipative nature of the collisions between solid particles leads to clustering. Within poly-disperse materials, the question of segregation is highly relevant but has not been addressed so far in microgravity. From parabolic flight experiments on dilute binary granular media, we show that clustering can trigger a segregation mechanism, and we observe, for the first time, the formation of layered structures in the bulk. [less ▲]

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See detailLes batteries vont bouleverser notre quotidien
Scharff, Christine; Ernst, Damien ULg

Article for general public (2017)

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See detailLe chez soi des animaux
Despret, Vinciane ULg

Book published by actes sud (2017)

Le livre raconte aux enfants des histoires sur le rapport des animaux à leur habitat et à leur identité. Pour comprendre qu’au-delà des ressemblances et des différences, “ainsi va la vie sur cette terre ... [more ▼]

Le livre raconte aux enfants des histoires sur le rapport des animaux à leur habitat et à leur identité. Pour comprendre qu’au-delà des ressemblances et des différences, “ainsi va la vie sur cette terre qui est, pour chacun et pour nous tous, notre chez-nous”. [less ▲]

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See detailOmbres de réalité
Choffray, Jean-Marie ULg

Book published by Amazon, Kindle Edition - Seconde édition (2017)

« Ombres de réalité » a pour objectif de partager avec vous nombre d’erreurs personnelles – factuelles et d’appréciation –, à la lumière de ce que d’autres ont eu l’élégance de nous transmettre. Le socle ... [more ▼]

« Ombres de réalité » a pour objectif de partager avec vous nombre d’erreurs personnelles – factuelles et d’appréciation –, à la lumière de ce que d’autres ont eu l’élégance de nous transmettre. Le socle de la réalité, lieu de convergence de ses ombres, et que décrit à merveille la comédie humaine, ne peut jamais être approché qu’au travers d’une recherche sincère et permanente. Apprendre à désapprendre résolument, apprendre à reconstruire patiemment, et apprendre à transmettre modestement, constituent le but ultime de la vie. Personnellement, je n’en vois pas d’autre aujourd’hui. Après une brève introduction, ou « Sortie de l’ombre », de courts chapitres couvrent un thème particulier, généralement à la lumière d’observations, d’expériences personnelles, ou de lectures qui m’ont touché. La sélection et l’ordre des sujets ne traduit aucun souci particulier, même si je ne crois plus beaucoup au hasard. Tous deux pourraient évoluer au fil des révisions que connaîtra ce texte dans les années à venir. Le choix actuel va de « Chacun pour soi » au « Secret du silence », en passant par « L’aventure à deux », « La foire aux illusions », « La tyrannie des marchés », « L’intérêt général », « Non ! merci », et « Une chance d’être ». Chaque thème peut être exploré isolément. A vous, donc, de constituer votre menu en fonction de votre curiosité et de votre appétit. [less ▲]

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See detailHow should proxies of Cognitive Reserve be evaluated in a population of healthy older adults?
Grotz, Catherine ULg; Seron, Xavier; Van Wissen, Marie et al

in International Psychogeriatrics (2017), 29(1), 123-136

Background: While some tools have been developed to estimate an individual’s cognitive reserve (CR), no study has assessed the adequacy of the method used for assessing these CR proxy indicators ... [more ▼]

Background: While some tools have been developed to estimate an individual’s cognitive reserve (CR), no study has assessed the adequacy of the method used for assessing these CR proxy indicators. Therefore, we aimed to determine the most appropriate method to estimate CR by comparing two approaches: 1) the common assessment of CR proxies in the literature (e.g., years of education) and 2) the calculation of a comprehensive index based on most significant parameters used in the estimation of CR. Methods: Data on CR proxies: (i.e., education, occupation and leisure activities) were obtained in a sample of 204 older adults. Regression analyses were used to develop the two indices of CR (i.e., ICR-standard and ICR-detailed) and to determine which index best represented the level of one’s CR. Results: The ICR-standard was calculated using a combination of the three most common measures of reserve in the literature: number of schooling years, complexity of the primary occupation and amount of current participation in stimulating activities. The ICR-detailed was calculated using the most significant parameters (established in initial analyses) of CR: highest level of education combined with the number of training courses, last occupation and amount of current participation in social and intellectual activities. The comparison of both indices showed that higher levels of ICR-standard and ICR-detailed were associated with a greater minimization of the effects of age on cognition. However, the ICR-detailed was more strongly associated to this minimization than the ICR-standard, suggesting that the ICR-detailed best reflect one’s CR. Conclusion: This study is the first to show that it is of great importance to question methods measuring CR proxies in order to develop a clinical tool allowing a comprehensive and accurate estimation of CR. [less ▲]

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See detailAux armes, professeurs de sciences !
du Jardin, Patrick ULg

Article for general public (2017)

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See detailHot-Melt Extrusion as a Continuous Manufacturing Process to Form Ternary Cyclodextrin Inclusion Complexes
Thiry, Justine ULg; Krier, Fabrice; Ratwatte, Shenelka et al

in European Journal of Pharmaceutical Sciences (2017), 96

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See detailFirst limits on the occurrence rate of short-period planets orbiting brown dwarfs
He, Matthias Y.; Triaud, Amaury H. M. J.; Gillon, Michaël ULg

in Monthly Notices of the Royal Astronomical Society (2017), 464

Planet formation theories predict a large but still undetected population of short-period terrestrial planets orbiting brown dwarfs. Should specimens of this population be discovered transiting relatively ... [more ▼]

Planet formation theories predict a large but still undetected population of short-period terrestrial planets orbiting brown dwarfs. Should specimens of this population be discovered transiting relatively bright and nearby brown dwarfs, the Jupiter-size and the low luminosity of their hosts would make them exquisite targets for detailed atmospheric characterisation with JWST and future ground-based facilities. The eventual discovery and detailed study of a significant sample of transiting terrestrial planets orbiting nearby brown dwarfs could prove to be useful not only for comparative exoplanetology but also for astrobiology, by bringing us key information on the physical requirements and timescale for the emergence of life. In this context, we present a search for transit-signals in archival time-series photometry acquired by the Spitzer Space Telescope for a sample of 44 nearby brown dwarfs. While these 44 targets were not particularly selected for their brightness, the high precision of their Spitzer light curves allows us to reach sensitivities below Earth-sized planets for 75% of the sample and down to Europa-sized planets on the brighter targets. We could not identify any unambiguous planetary signal. Instead, we could compute the first limits on the presence of planets on close-in orbits. We find that within a 1.28 day orbit, the occurrence rate of planets with a radius between 0.75 and 3.25 R$_\oplus$ is {\eta} < 67 $\pm$ 1%. For planets with radii between 0.75 and 1.25 R$_\oplus$, we place a 95% confident upper limit of {\eta} < 87 $\pm$ 3%. If we assume an occurrence rate of {\eta} = 27% for these planets with radii between 0.75 and 1.25 R$_\oplus$, as the discoveries of the Kepler-42b and TRAPPIST-1b systems would suggest, we estimate that 175 brown dwarfs need to be monitored in order to guarantee (95%) at least one detection. [less ▲]

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See detailWater loss from terrestrial planets orbiting ultracool dwarfs: implications for the planets of TRAPPIST-1
Bolmont, E.; Selsis, F.; Owen, J. E. et al

in Monthly Notices of the Royal Astronomical Society (2017), 464

Ultracool dwarfs (UCD; $T_{\rm eff}<\sim3000~$K) cool to settle on the main sequence after $\sim$1 Gyr. For brown dwarfs, this cooling never stops. Their habitable zone (HZ) thus sweeps inward at least ... [more ▼]

Ultracool dwarfs (UCD; $T_{\rm eff}<\sim3000~$K) cool to settle on the main sequence after $\sim$1 Gyr. For brown dwarfs, this cooling never stops. Their habitable zone (HZ) thus sweeps inward at least during the first Gyr of their lives. Assuming they possess water, planets found in the HZ of UCDs have experienced a runaway greenhouse phase too hot for liquid water prior to entering the HZ. It has been proposed that such planets are desiccated by this hot early phase and enter the HZ as dry worlds. Here we model the water loss during this pre-HZ hot phase taking into account recent upper limits on the XUV emission of UCDs and using 1D radiation-hydrodynamic simulations. We address the whole range of UCDs but also focus on the planets recently found around the $0.08~M_\odot$ dwarf TRAPPIST-1. Despite assumptions maximizing the FUV-photolysis of water and the XUV-driven escape of hydrogen, we find that planets can retain significant amounts of water in the HZ of UCDs, with a sweet spot in the $0.04$-$0.06~M_\odot$ range. We also studied the TRAPPIST-1 system using observed constraints on the XUV-flux. We find that TRAPPIST-1b and c may have lost as much as 15 Earth Oceans and planet d -- which might be inside the HZ -- may have lost less than 1 Earth Ocean. Depending on their initial water contents, they could have enough water to remain habitable. TRAPPIST-1 planets are key targets for atmospheric characterization and could provide strong constraints on the water erosion around UCDs. [less ▲]

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See detailRossiter-McLaughlin models and their effect on estimates of stellar rotation, illustrated using six WASP systems
Brown, D. J. A.; Triaud, A. H. M. J.; Doyle, A. P. et al

in Monthly Notices of the Royal Astronomical Society (2017), 464

We present new measurements of the projected spin--orbit angle $\lambda$ for six WASP hot Jupiters, four of which are new to the literature (WASP-61, -62, -76, and -78), and two of which are new analyses ... [more ▼]

We present new measurements of the projected spin--orbit angle $\lambda$ for six WASP hot Jupiters, four of which are new to the literature (WASP-61, -62, -76, and -78), and two of which are new analyses of previously measured systems using new data (WASP-71, and -79). We use three different models based on two different techniques: radial velocity measurements of the Rossiter--McLaughlin effect, and Doppler tomography. Our comparison of the different models reveals that they produce projected stellar rotation velocities ($v \sin I_{\rm s}$) measurements often in disagreement with each other and with estimates obtained from spectral line broadening. The Bou\'e model for the Rossiter--McLaughlin effect consistently underestimates the value of $v\sin I_{\rm s}$ compared to the Hirano model. Although $v \sin I_s$ differed, the effect on $\lambda$ was small for our sample, with all three methods producing values in agreement with each other. Using Doppler tomography, we find that WASP-61\,b ($\lambda=4^\circ.0^{+17.1}_{-18.4}$), WASP-71\,b ($\lambda=-1^\circ.9^{+7.1}_{-7.5}$), and WASP-78\,b ($\lambda=-6^\circ.4\pm5.9$) are aligned. WASP-62\,b ($\lambda=19^\circ.4^{+5.1}_{-4.9}$) is found to be slightly misaligned, while WASP-79\,b ($\lambda=-95^\circ.2^{+0.9}_{-1.0}$) is confirmed to be strongly misaligned and has a retrograde orbit. We explore a range of possibilities for the orbit of WASP-76\,b, finding that the orbit is likely to be strongly misaligned in the positive $\lambda$ direction. [less ▲]

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See detailTHE LACTOPEROXIDASE SYSTEM, A NATURAL BIOCHEMICAL BIOCONTROL AGENT FOR PRE- AND POST-HARVEST APPLICATIONS
Bafort, Françoise ULg; Parisi, Olivier ULg; Perraudin, Jean-Paul et al

in Journal of Phytopathology (2017), 165(1), 22-34

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See detailEnonciation et modes d'existence
Dondero, Maria Giulia ULg

in Nouveaux Actes Sémiotiques (2017)

Cet article aborde les relations entre sémiotique et philosophie latourienne à partir de la théorie de l’énonciation, cette dernière se situant tant aux fondements du projet disciplinaire de la sémiotique ... [more ▼]

Cet article aborde les relations entre sémiotique et philosophie latourienne à partir de la théorie de l’énonciation, cette dernière se situant tant aux fondements du projet disciplinaire de la sémiotique francophone contemporaine qu’à la base de la réflexion de Bruno Latour, des années 1970 jusqu’à présent . Notre propos se déploie en deux moments : dans un premier temps, nous revenons sur l’article "Petite Philosophie de l’énonciation" (1998), et nous en suivons le développement dans l’Enquête sur les modes d’existence (2012). Dans un second temps, nous réalisons une rapide archéologie de la théorie de l’énonciation dans la sémiotique contemporaine, afin de mettre en lumière les liens entre différentes traditions sémiotiques et la théorie latourienne. Plus précisément, nous nous attachons aux propositions récentes de Jacques Fontanille et de Claudio Paolucci, en prenant également en considération les contributions d’Umberto Eco et Patrizia Violi. Il s’agit de voir comment les sémioticiens peuvent tirer profit de la théorie latourienne des modes d’existence et vice versa. [less ▲]

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See detailImpact of food type on respiration, fractionation and turnover of carbon and nitrogen stable isotopes in the marine amphipod Gammarus aequicauda (Martynov, 1931).
Remy, François ULg; Darchambeau, François ULg; Melchior, Aurélie et al

in Journal of Experimental Marine Biology & Ecology (2017), 486

This study experimentally determined the impact of food source type on turnover rate and trophic enrichment factors (TEFs or ∆) of δ13C and δ15N, as well as on respiration rate, in captive populations of ... [more ▼]

This study experimentally determined the impact of food source type on turnover rate and trophic enrichment factors (TEFs or ∆) of δ13C and δ15N, as well as on respiration rate, in captive populations of the marine amphipod Gammarus aequicauda. Gammarus aequicauda (318 individuals) were fed ad libitum with three food sources animal, algae, and dead Posidonia oceanica leaves (also called “litter”), varying in palatability, digestibility, nutritional qualities and isotopic compositions, for between four and six weeks in a controlled feeding experiment. The resulting death rate was lower for the amphipods fed with animal treatment (30.9%) than for individuals fed with algal (65.9%) or litter treatment (64.4%), indicating a better fitness of the individuals fed with the animal food source. Respiration rates also differed highly among the treatments. Animal treatment showed higher respiration rates than algal and litter treatments, potentially due to the toxicity of the algae and the very low nutritional quality of the litter. Amphipods fed with these treatments might have entered in a “low activity state” to cope with these unsuitable food sources, inducing low respiration rates. Due to the very low assimilation and toxicity of the algae source, turnover rate for δ13C was impossible to determine. Turnover rate for δ13C was much faster (half-life = 12.55 days) for amphipods fed with the animal food source than for amphipods fed with litter (half-life = 51.62 days), showing the faster assimilation of the most nutritionally optimal food sources by G. aequicauda. Turnover for δ15N was impossible to determine because the amphipods were already at isotopic equilibrium at the beginning of the experiment. Despite the detritus feeder status of Gammarus aequicauda, TEFs for the animal treatments were in accordance with values generally found for carnivorous organisms (∆13C = 0.9 ± 0.7‰; ∆15N = 2.9 ± 0.6‰). TEFs for the litter treatment were in accordance with values generally corresponding to detritivorous organisms (∆13C = 1.2‰; ∆15N = 1.0 ± 0.4‰). SIAR mixing model outputs obtained with these new TEF values were more constrained and coherent than outputs obtained with general literature TEFs. This study thus demonstrated the non-negligible impact of the food source on Gammarus aequicauda physiological status, fitness and turnover rates, but also on TEFs—highlighting the importance of TEF experimental calculations for every potential food source of a given organism to ensure more robust isotopic data interpretation. [less ▲]

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See detailMethane balance of an intensively grazed pasture and estimation of the enteric methane emissions from cattle
Dumortier, Pierre ULg; Aubinet, Marc ULg; Beckers, Yves ULg et al

in Agricultural and Forest Meteorology (2017), 232

The methane turbulent fluxes of an intensively grazed pasture were measured continuously from June 2012 to December 2013 at the Dorinne Terrestrial Observatory (DTO) in Belgium. During grazing periods ... [more ▼]

The methane turbulent fluxes of an intensively grazed pasture were measured continuously from June 2012 to December 2013 at the Dorinne Terrestrial Observatory (DTO) in Belgium. During grazing periods, the fluxes were dominated by enteric fermentation and were found to be strongly related to cow stocking density. In 2013, total emission from the pasture was found between 9 and 11 g CH4 m−2, 97% of which being emitted during grazing periods. Emission per LU (livestock unit) was estimated in a non-invasive way by integrating eddy covariance fluxes over large periods and by assuming a homogeneous average cattle disposition on the pasture. This estimate was compared to the one obtained during confinement periods, where cows were confined in a small part of the pasture. The emission per LU varied between 104 and 134 g CH4 LU−1 day−1 (13 and 17 g CH4 kg DMI−1), depending on the dataset and the computation method used. Diel course was characterized by two emission peaks, one in the morning and a larger one in the afternoon. For rest periods (no cattle on the pasture), small emissions were observed (median and mean values of 0.5 and 1.5 mg CH4 m−2 day−1, respectively). [less ▲]

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See detailQuelques idées générales à propos de la compréhension en mathématiques
Bair, Jacques ULg

E-print/Working paper (2017)

Dans cet article, nous apportons des éléments de réponse à la question générale suivante : "Que signifie bien comprendre en mathématiques ?" Nous nous demandons pourquoi il est difficile d'y répondre et ... [more ▼]

Dans cet article, nous apportons des éléments de réponse à la question générale suivante : "Que signifie bien comprendre en mathématiques ?" Nous nous demandons pourquoi il est difficile d'y répondre et apportons une piste de solution en distinguant les activités de production de celles de reproduction. De plus, nous abordons le problème étudié d'un point de vue aussi bien local que global. Enfin, nous nous interrogeons sur l'incompréhension en mathématiques en proposant une typologie, en repérant des causes possibles d'incompréhension et en donnant quelques conseils pratiques. [less ▲]

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See detailRelevance of vitamin D in the pathogenesis and therapy of frailty.
Bruyère, Olivier ULg; Cavalier, Etienne ULg; Buckinx, Fanny ULg et al

in Current Opinion in Clinical Nutrition & Metabolic Care (2017), 20(1), 26-29

PURPOSE OF REVIEW: This article reviews recently published evidence regarding the role of vitamin D in the physiopathology of physical frailty in elderly populations and its role in the management of this ... [more ▼]

PURPOSE OF REVIEW: This article reviews recently published evidence regarding the role of vitamin D in the physiopathology of physical frailty in elderly populations and its role in the management of this geriatric condition. RECENT FINDINGS: Some recent studies have found a low level of 25-hydroxyvitamin D, considered the best marker of vitamin D status, in frail individuals. All prospective studies consistently report that low vitamin D status is associated with an increased risk of becoming frail. Recent studies also suggest that the relationship between vitamin D status and frailty is largely mediated by the development of sarcopenia. Very few well designed randomized controlled trials are available that assess the effectiveness of vitamin D supplementation in the prevention or management of frailty. In the absence of specific guidelines, a minimal serum 25-hydroxyvitamin D level of 75 nmol/l is proposed for frail elderly patients by some scientific societies. The doses necessary to reach this target are between 800 and 2000 IU/day. SUMMARY: Several studies suggest a potential effect of vitamin D on physical frailty but large clinical trials are lacking at this time to provide solid evidence of clinical benefit. [less ▲]

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