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See detailA phase-resolved XMM-Newton campaign on the colliding-wind binary HD 152248
Sana, H.; Stevens, I. R.; Gosset, Eric ULg et al

in Monthly Notices of the Royal Astronomical Society (2004), 350(3), 809-828

We report the first results of an XMM-Newton monitoring campaign of the open cluster NGC 6231 in the Sco OB 1 association. This first paper focuses on the massive colliding-wind binary HD 152248, which is ... [more ▼]

We report the first results of an XMM-Newton monitoring campaign of the open cluster NGC 6231 in the Sco OB 1 association. This first paper focuses on the massive colliding-wind binary HD 152248, which is the brightest X-ray source of the cluster. The campaign, with a total duration of 180 ks, was split into six separate observations, following the orbital motion of HD 152248. The X-ray flux from this system presents a clear, asymmetric modulation with the phase and ranges from 0.73 to 1.18 x 10(-12) erg s(-1) cm(-2) in the 0.5-10.0 keV energy band. The maximum of the emission is reached slightly after apastron. The EPIC spectra are quite soft, and peak around 0.8-0.9 keV. We characterize their shape using several combinations Of MEKAL models and power-law spectra and we detect significant spectral variability in the 0.5-2.5 keV energy band. We also perform 2D hydrodynamical simulations using different sets of parameters that closely reproduce the physical and orbital configuration of the HD 152248 system at the time of the six XMM-Newton pointings. This allows a direct confrontation of the model predictions with the constraints deduced from the X-ray observations of the system. We show that the observed variation of the flux can be explained by a variation of the X-ray emission from the colliding-wind zone, diluted by the softer X-ray contribution of the two O-type stars of the system. Our simulations also reveal that the interaction region of HD 152248 should be highly unstable, giving rise to shells of dense gas that are separated by low-density regions. Finally, we perform a search for short-term variability in the light curves of the system and we show that trends are present within several of the 30-ks exposures of our campaign. Further, most of these trends are in good agreement with the orbital motion and provide a direct constraint on the first-order derivative of the flux. In the same context, we also search for long-range correlations in the X-ray data of the system, but we only marginally detect them in the high-energy tail of the signal. [less ▲]

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See detailPhase-resolved XMM-Newton observations of the massive WR+O binary WR 22
Gosset, Eric ULg; Nazé, Yaël ULg; Sana, H. et al

in Astronomy and Astrophysics (2009), 508

Aims. To better understand the phenomenon of colliding winds in massive binary stars, we study the X-ray lightcurve of a WR+O system of the Carina region, a system well known for the high mass of its ... [more ▼]

Aims. To better understand the phenomenon of colliding winds in massive binary stars, we study the X-ray lightcurve of a WR+O system of the Carina region, a system well known for the high mass of its primary.<BR /> Methods: Phase-resolved X-ray observations of the massive WR+O binary system WR 22 were performed with the XMM-Newton facility. We observed the object at seven different phases from near apastron to near periastron.<BR /> Results: The X-ray spectrum can be represented by a two-component, optically thin, thermal plasma model with a first one at a typical temperature of 0.6 keV and a second hotter one in the range 2.0-4.5 keV. The hot component is indicative of a colliding wind phenomenon, but its flux is remarkably constant with time despite the high eccentricity of the orbit. Although surprising at first, this actually does not contradict the results of the hydrodynamical simulations of the wind collision that we performed. When the system goes from apastron to periastron, the soft part of the X-ray flux is progressively lowered by an increasing intervening absorbing column. This behaviour can be interpreted in terms of an X-ray emitting plasma located near the O star, but not fully intrinsic to it, and accompanying the star when it dives into the wind of the WR component. A model is presented that interprets most of the observational constraints. This model suggests that the mass-loss rate of dot{M}[SUB]WR[/SUB] 1.6 à 10[SUP]-5[/SUP] {M}[SUB]ȯ[/SUB] yr[SUP]-1[/SUP] assumed for the WR could still be slightly too high, whereas it is already lower than other published values. From the comparison of the observed and the expected absorptions at phases near periastron, we deduce that the hard X-ray emitting collision zone should at least have a typical size of 50-60 R[SUB]ȯ[/SUB], but that the size for the soft X-ray emitting region could reach 244 R[SUB]ȯ[/SUB] if the assumed mass-loss rate is correct. We also present an upper limit to the X-ray luminosity of the WR component that further questions the existence of intrinsic X-ray emission from single WN stars.<BR /> Based on observations with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA). Research Associate FNRS (Belgium). Postdoctoral Researcher FNRS (Belgium). [less ▲]

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See detailPhase-separated microstructures in "all-acrylic" thermoplastic elastomers
Leclère, Philippe; Rasmont, A.; Brédas, Jean-Luc et al

in Macromolecular Symposia (2001), 167

Atomic Force Microscopy (AFM) is used to study the phase separation process occurring in block copolymers in the solid state. Measuring simultaneously the amplitude and the phase of the oscillating ... [more ▼]

Atomic Force Microscopy (AFM) is used to study the phase separation process occurring in block copolymers in the solid state. Measuring simultaneously the amplitude and the phase of the oscillating cantilever in tapping-mode operation provides the surface topography along with the cartography of microdomains with different mechanical properties. This in turn allows to characterize the organization of the various components at the surface in terms of well-defined morphologies (e.g., spheres, cylinders, or lamellae). Here this approach is applied to a series of symmetric triblock copolymers made of a central elastomeric segment (polyalkylacrylate) surrounded by two thermoplastic sequences (polymethylmethacrylate). The occurrence of microphase separation in these materials and the resulting microscopic morphology are essential factors for determining their potential applications as a new class of thermoplastic elastomers. This paper describes how the surface morphology can be controlled by the molecular structure of the copolymers (volume ratio between the sequences, molecular weight, length of the alkyl side group) and by the experimental conditions used for the preparation of the films. The molecular structure of the chains is fully determined by the synthesis of the copolymers via living anionic polymerization while the parameters that can be modified when preparing the samples are the nature of the solvent and the thermal annealing of the films. Finally, we report on a systematic comparison between images and approach-retract curve data. We show that this experimental comparison allows the origin of the contrast that produces the image to be straightforwardly evaluated. The method provides an unambiguous quantitative measurement of the contribution of the local mechanical response to the image. We show that most of the contrast in the height and phase images is due to variations in local mechanical properties and not in topography. [less ▲]

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See detailPhase-shifting real time interferometry that uses bismut silicon oxide crystals
Georges, Marc ULg; Lemaire, Philippe

in Applied Optics (1995), 34(32), 7497-7506

A bismuth silicon oxide crystal is used in the diffusion regime as a dynamic recording medium in a real-time holographic interferometer based on anisotropic self-diffraction. This device is connected with ... [more ▼]

A bismuth silicon oxide crystal is used in the diffusion regime as a dynamic recording medium in a real-time holographic interferometer based on anisotropic self-diffraction. This device is connected with an interferogram-analysis method that uses the phase-shifting technique for quantitative measurement of diffusive-reflecting object deformations. In addition to the usual error sources in phase shifting, the temporal interferogram erasure is studied and is found weakly perturbative for the measured phase. Itis shown that quantitative measurements are possible for low-intensity object beams (8 μW/cm2) and a large observed area. Apractical situation of defect monitoring in a composite structure is presented. [less ▲]

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See detailPhase-transition regularities in critical constants, fusion temperatures and enthalpies of chemically similar chainlike structures
Balaban, A. T.; Klein, D. J.; March, N. H. et al

in Chemphyschem : A European Journal of Chemical Physics and Physical Chemistry (2005), 6(9), 1741-1745

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See detailPhaseolus lunatus L.
Baudoin, Jean-Pierre ULg

in Plant Resources of Tropical Africa (PROTA Foundation) (2006), 1

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See detailPhases of Polonium via Density Functional Theory
Verstraete, Matthieu ULg

in Physical Review Letters (2010), 104

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See detailLes phases successives de l'évolution de certains conduits vadoses.
Ek, Camille ULg

in Actes du troisième Congrès international de Spéléologie - Compte-rendu (1964)

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See detailPhD committe presentation - 3rd year
Serino, Gennaro ULg

Report (2014)

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See detailPhellinus caribaeo-quercicolus sp. nov., parasitic on Quercus cubana: taxonomy and preliminary phylogenetic relationships.
Decock, Cony; Herrera Figueroa, Sara; Robledo, Gerardo et al

in Mycologia (2006), 98(2), 265-74

Phellinus caribaeo-quercicolus sp. nov. is described from several collections made in western Cuba, so far exclusively on Quercus cubana. The species is characterized by a perennial, resupinate basidiomes ... [more ▼]

Phellinus caribaeo-quercicolus sp. nov. is described from several collections made in western Cuba, so far exclusively on Quercus cubana. The species is characterized by a perennial, resupinate basidiomes, cushion-shaped to nodulose and multi-layered when old, apically hooked to hamate hymenial setae, and ellipsoid to broadly ellipsoid, thin- to thick-walled, hyaline to faintly yellowish basidiospores, 4.5-5.5 x 3.5-4.5 microm. The species is compared to other Phellinus species with hooked setae, especially Phellinus undulatus, also recorded in Cuba. The preliminary phylogenetic relationships of Ph. caribaeo-quercicolus within the poroid Hymenochaetales complex of genera is presented and discussed here. [less ▲]

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See detailPhencyclidine inhibition of the acetylcholine receptor: measurement of cation flux in a sympathetic neuronal cell line using 22Na+ and spectroscopic detection of Cs+.
Sachs, A. B.; Leprince, Pierre ULg; Karpen, J. W. et al

in Archives of Biochemistry & Biophysics (1983), 225(2), 500-4

The site of action of phencyclidine, a powerful and increasingly abused drug, in sympathetic nerve cells has not previously been identified. Here it is demonstrated that phencyclidine is a powerful ... [more ▼]

The site of action of phencyclidine, a powerful and increasingly abused drug, in sympathetic nerve cells has not previously been identified. Here it is demonstrated that phencyclidine is a powerful, noncompetitive inhibitor of the nicotinic acetylcholine receptor in a sympathetic nerve cell line, PC-12. In the presence of 1 mM carbamoylcholine the rate of the receptor-controlled influx of 22Na+ is reduced by a factor of 2 by 0.7 microM phencyclidine. Increasing concentrations of carbamoylcholine cannot reverse the inhibitory effect of the drug. Both the transmission of electrical signals between nerve cells and the secretion of catecholamines in the PC-12 cell line depend on the receptor-controlled ion flux. Thus phencyclidine interferes with at least two specific, physiologically important functions of these nerve cells. A new spectroscopic method has been developed to measure cation flux in cells. It is shown that this method can replace measurements of tracer ion flux. [less ▲]

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See detailPhenolic acid-rich extract of sweet basil restores cholesterol and triglycerides metabolism in high fat diet-fed mice: A comparison with fenofibrate
Harnafi, H.; Ramchoun, M.; Tits, Monique ULg et al

in Biomedicine & Preventive Nutrition (2013), 3(4), 393-397

Many spices are often added to foods as additives to enhance organoleptic qualities, such as flavor, aroma and color. Sweet basil (Ocimum basilicum L.) family of Lamiaceae is widely used in cooking for ... [more ▼]

Many spices are often added to foods as additives to enhance organoleptic qualities, such as flavor, aroma and color. Sweet basil (Ocimum basilicum L.) family of Lamiaceae is widely used in cooking for its culinary attributes. In this study, we aimed at the investigation of the hypocholesterolemic and hypotriglyceridemic activities of the basil phenolic acid-rich extract in high fat diet-induced hyperlipemic mice. Hyperlipemia was developed by a high fat diet containing cholesterol, lard and cholic acid. At the beginning of the experiment, animals were divided into three groups, one of them served as normolipidemic control group (NCG), the second hyperlipidemic control group (HCG) and the third basil-treated group (BTG). After 5 weeks of treatment, basil phenolic acid-rich extract significantly decreased plasma total cholesterol, triglycerides and LDL-cholesterol (-42%,-42% and -86%, respectively, P < 0.001). However, HDL-cholesterol was increased (+79%, P < 0.001). The extract reduced the atherogenic index and LDL/HDL-C ratio (-88% and -94%, respectively, P < 0.001). The reductions of liver total cholesterol and triglycerides were of -50% (P < 0.01) and -58% (P < 0.01), respectively. The hypolipemic effect of the phenolic acid-rich extract is comparable to that exerted by fenofibrate. This drug significantly reduced plasma total cholesterol, triglycerides and LDL-cholesterol (-25.5%, -51%, and -83.5%, respectively, P < 0.001) and increased plasma HDL-cholesterol (+136%, P < 0.001). On the other hand, fenofibrate significantly decreased atherogenic index and LDL/HDL-cholesterol ratio (-91% and -93%, respectively, P < 0.001). The fenofibrate decreased hepatic total cholesterol by 59.5% and triglycerides by 72%, respectively (P < 0.01). HPLC analysis led to identify four major compounds: caftaric acid, cafeic acid, chicoric acid and rosmarinic acid. In conclusion, the Sweet basil contains phenolic products that are able to lower hyperlipidemia and prevent atherosclerosis. © 2013 Elsevier Masson SAS. All rights reserved. [less ▲]

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See detailPhenolic Compounds and Terpenoids from Hypericum lanceolatum
Wabo, H. K.; Kowa, T. K.; Lonfouo, A. H. et al

in Records of Natural Products (2012), 6(2), 94-100

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See detailPhenolic compounds in apple juices - Method of quantification by UHPLC-UV and UHPLC-MS/MS
Verdu, Cindy ULg; Gatto, Julia; Freuze, Ingrid et al

Poster (2012, July)

An UPHLC-UV/MS/MS method was developed for separation and quantification of major polyphenolic compounds present in apple juice. The main classes of polyphenols studied here are monomeric or polymeric ... [more ▼]

An UPHLC-UV/MS/MS method was developed for separation and quantification of major polyphenolic compounds present in apple juice. The main classes of polyphenols studied here are monomeric or polymeric flavan-3-ols, phenolic acids, flavonols and dihydrochalcones. compounds were quantified simultaneously with the two detection systems, i.e. with UV-PDA detection and ESI-triple quadrupole mass detection used in the selected reaction monitoring (SRM) mode. Each method (UHPLC-UV and UHPLC-SRM) was assessed with 2 different apple juice samples and linearity, limit of detection and quantification (LOD and LOQ), accuracy and precision tests were realized on the 15 major compounds. Despite the validation of the UHPLC-UV and UHPLC-SRM methods, significantly different results were obtained by comparing UHPLC-UV and UHPLC-SRM quantifications. Three groups of polyphenols were observed, the first one with equivalent results between the two quantification methods (in most cases), and the two others with overestimated or underestimated results when comparing UHPLC-UV and UHPLC-SRM quantifications. [less ▲]

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See detailPhenological patterns in a natural population of a tropical timber tree species, Milicia excelsa (Moraceae): evidence of Isolation By Time and its interaction with feeding strategies of dispersers
Daïnou, Kasso ULg; Laurenty, Eric; Mahy, Grégory ULg et al

in American Journal of Botany (2012), 99(9), 1-11

Population genetic structuring over limited timescales is commonly viewed as a consequence of spatial constraints. Indirect approaches have recently revealed existence of reproductive isolation due to ... [more ▼]

Population genetic structuring over limited timescales is commonly viewed as a consequence of spatial constraints. Indirect approaches have recently revealed existence of reproductive isolation due to flowering time (the so-called isolation by time, IBT). Since phenological processes can be subject to selection, the persistence of flowering asynchrony may be due to opposing selective pressures during mating, dispersal and regeneration phases. Our study aimed to investigate phenology, fruit-handling by animals and their interaction, in a timber tree species, Milicia excelsa. We analyzed phenological data collected over a 6-year period on 69 genotyped trees in a Cameroonian natural rainforest complemented by data from germination trials and field observations of dispersers. Initiation of flowering correlated with variation in temperature and relative humidity, but was also affected by genetic factors: pairwise differences in flowering time between nearby individuals correlated with kinship coefficient, and earliness of flowering remained stable over time. A decrease in mean seed production per fruit with increasing flowering time suggests selection against late bloomers. However, germination rate was not affected by seed collection date, and the main seed disperser, the bat Eidolon helvum, seemed to increase in abundance at the end of the reproductive season, and preferred trees in open habitats where early and late bloomers are expected. The pairwise approach performs well to detecting IBT. The persistence of different mating pools in such a case may result from a trade-off between selective forces during the mating and seed dispersal processes. [less ▲]

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See detailPhenologie des Basidiomycetes lignicoles de l'ile de Laing (Papouasie Nouvelle-Guinee)
Castillo Cabello, Gabriel ULg; Demoulin, Vincent ULg

in Belgian Journal of Botany (1998)

In the framework of a study of wood-inhabiting fungi on Laing Island, a small coral island located on the northern coast of Papua New Guinea, we have established a phenological table of the 96 taxa of ... [more ▼]

In the framework of a study of wood-inhabiting fungi on Laing Island, a small coral island located on the northern coast of Papua New Guinea, we have established a phenological table of the 96 taxa of encountered Basidiomycetes. Within six species presenting large phenological amplitude, two groups can be distinguished. On the one hand a group of species (Hexagonia tenuis, Polyporus philippinensis and Microporus xanthopus) with narrow ecological amplitude restricted to dense vegetation cover and thus growing in an environment buffered against desiccation and on the other hand a group of species (Pycnoporus sanguineus, Schizophyllum commune and Trametes scabrosa) with a very large ecological amplitude very resistant to desiccation. Furthermore, a large number of species are found too sporadically in order to draw some conclusions concerning their phenology. [less ▲]

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See detailPhénologie et diamètre de fructification du wengé, Millettia laurentii De Wild : implications pour la gestion
Menga, Pisco; Nasi, Robert; Bayol, Nicolas et al

in Bois et Forêts des Tropiques (2012), 312(2), 31-41

L'étude fait partie d'un effort de caractérisation de l'autoécologie du wengé, Millettia laurentii De Wild., une essence majeure de la filière bois en République démocratique du Congo (Rdc). Dans cet ... [more ▼]

L'étude fait partie d'un effort de caractérisation de l'autoécologie du wengé, Millettia laurentii De Wild., une essence majeure de la filière bois en République démocratique du Congo (Rdc). Dans cet article sont présentés les éléments relatifs à la phénologie foliaire et reproductrice de l'espèce et les implications de ces résultats pour la gestion. La phénologie de 774 arbres, répartis dans trois concessions d'exploitation forestière de la Société de développement forestier (SODEFOR) dans la région de Mai-Ndombe (258 arbres par site) a été suivie mensuellement pendant 15 mois. Millettia laurentii présente une phénologie foliaire et reproductrice fortement saisonnière. La chute des feuilles et l'apparition des nouvelles feuilles se produisent deux fois par an, respectivement pendant les saisons sèches et au début des saisons pluvieuses. La phénologie reproductrice (floraison et fructification) présente également une forte saisonnalité, avec cependant des différences entre sites. La floraison se produit au début des saisons pluvieuses en même temps que l'apparition des feuilles. La maturité complète avec possibilité de récolte des semences (éclatement de gousses) a lieu durant l'intersaison (fin de la saison sèche et début de la saison pluvieuse). Le type de floraison est majoritairement annuel. Les individus fleurissent par groupe, mais chaque groupe ne fleurit qu'une fois par an. Toutefois, en dehors des pics s'observent des événements de floraison et de fructification occasionnels, en particulier dans le site le plus arrosé et le moins saisonnier. Millettia laurentii est une espèce à fructification précoce. Le diamètre minimal de fertilité est inférieur ou égal à 10 cm mais l'efficacité de la fructification dépend néanmoins du diamètre et du statut social des arbres. Le diamètre minimum d'exploitation (Dme) en vigueur en Rdc (60 cm) est supérieur au diamètre de fructification régulière (Dfr) qui se situe entre 40-50 cm, ce qui est nécessaire pour le maintien de semenciers dans les peuplements après le passage en exploitation. [less ▲]

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See detailPhénologie et domaine vital de la salamandre terrestre Salamandra salamandra terrestris (Amphibia, Caudata) dans un bois du Pays de Herve (Belgique)
Denoël, Mathieu ULg

in Cahiers d'Ethologie (1996), 16

The aim of this study was to approach some aspects of the life-history of the fire salamander Salamandra s. terrestris in a small wood of the Vesdre Valley (Liege Province, Belgium). In 1996, 189 ... [more ▼]

The aim of this study was to approach some aspects of the life-history of the fire salamander Salamandra s. terrestris in a small wood of the Vesdre Valley (Liege Province, Belgium). In 1996, 189 salamanders were marked and 68 recaptured. Their cartographic position and the meteorological conditions were noted. Salamanders were active from March to October, mated from May to August and females gave birth to larvae in March-April. Only a small part of the population was active at the same moment. Salamanders were generally faithful to a home range, in spite of some erratic individuals, and are apparently non-territorial. They moved principally along a path. The population is important but strongly threatened by the perturbation of its environment: stream drying, clearing and forest fire. [less ▲]

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See detailPhénologie et intensité de la migration postnuptiale diurne en Ardenne du nord-est par le suivi migratoire (Ramecroix, 2006 à 2010)
Beckers, Arnaud ULg; Baron, André

in Aves (2014), 51(2), 87-106

We present the results of five years of monitoring postnuptial migration in the northeast Ardennes (the Ramecroix site) from 2006 to 2010. The timing and intensity of migration have been calculated for ... [more ▼]

We present the results of five years of monitoring postnuptial migration in the northeast Ardennes (the Ramecroix site) from 2006 to 2010. The timing and intensity of migration have been calculated for the 19 commonest species. Phenology for each species varied markedly from year to year. The passage of two particular species (Northern Lapwing and Song Trush) was extremely concentrated in time. Comparison with data from the Netherland and from Les Awirs (Liège, Belgium) show differences between locations, for which we propose some explanations. The full dataset constitute a useful benchmark for future studies on the spatial variability of migration flow. [less ▲]

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See detailPhenology of marine turtle nesting revealed by a statistical model of the nesting season
Girondot, Marc; Rivalan, Philippe; Wongsopawiro, Ronald et al

in BMC Ecology (2006)

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